US3370546A - Selective printing machine employing magnetic fields - Google Patents

Description

Feb. 27, 1968 R. MULLER 7 3,370,545

SELECTIVE PRINTING MACHINE EMPLOYING MAGNETIC FIELDS Filed May 26, 1965 '7 Sheets-Sheet l INVENTOR.

RUDOLF MULLER Feb. 27, 1968 R, MULLER 3,370,546

SELECTIVE PRINTING MACHINE EMPLOYING MAGNETIC FIELDS Filed May 26, 1965 7 Sheets-Sheet 2 45 32d 32e 32f a 7 36 78 36b 38c 78c IN V EN TOR.

' RUDOLF MULLER BY R. MULLER Feb. 27, 1968 SELECTIVE PRINTING MACHINE EMPLOYING MAGNETIC FIELDS 7 Sheets-Sheet 5 Filed May 26, 1965 INVENTOR.

RUDOLF MULLER Feb. 27, 1968 R. MULLER 3,370,546

SELECTIVE PRINTING MACHINE EMFLOYING MAGNETIC FIELDS Filed May 26, 1965 '7 Sheets-Sheet 4 a v F/g.3a I

INVENTOR.

RUDOLF MULLER BY Feb. 27,1968 R. MULLER 3,370,546

SELECTIVE PRINTING MACHINE EMPLOYING MAGNETIC FIELDS I Filed May 26, 1965 7 Sheets-Sheet 5 96 22/ Q 5 7/ r2 r3 2 lzoa 19% T 20c -21 9/ 2 i 79c IN V EN TOR.

RUDOLF MULLER BY R. MULLER Feb. 27, 1968 SELECTIVE PRINTING MACHINE EMPLOYING MAGNETIC FIELDS Filed May 26, 1965 7 Sheets-Sheet 6 INVENTOR.

RUDOLF MULLER R. MULLER Feb. 27, 1968 SELECTIVE PRINTING MACHINE. E

MPLOYING MAGNETIC FIELDS Filed May 26, 1965 Y 7 Sheets-Sheet 7 INVENTOR.

RUDOLF MULLER United States Patent 3 370,546 SELECTIVE PRINTIN G MACHINE EMPLOYING MAGNETIC FIELDS Rudolf Muller, Grunwald, near Munich, Germany, assignor to Agfa Aktieugeseilschaft, Leverkusen, German y Filed May 26, 1965, Ser. No. 458,928 Claims priority, appiication Germany, June 5, 1964, A 4,229 24 Claims. (Cl. 10191) ABSTRACT OF THE DISCLOSURE Selected text sections formed of magnetizable ink on a first surface are transferred by the magnetic fields of electromagnets to a second surface, while non-selected text sections remain on the first surface so that copy sheets having different selected text sections can be produced from the one printing form having all text sections.

The present invention relates to a selective printing machine, and to a method of selective printing, and more particularly to an apparatus and method for printing only selected sections of a printing form which is inked with a magnetic ink.

Known printing machines for printing selected sections of a printing form use pressure rollers which are moved between a printing position for printing a selected section, and an inoperative position for omitting an undesired section. Due to the substantial masses involved in rapidly shifting the pressure roller, the speed of the machine is limited, and the operation is comparatively noisy.

It is one object of the invention to overcome this disadvantage of known machines for printing selected sections of a text, and to provide a selective printing machine in which only ink is transferred from selected sections of a first surface to corresponding sections of a second surface by a magnetic field.

Another object of the invention is toprovide a selective printing machine in which no heavy masses are moved, and which operates at high speed without producing 'a substantial noise.

Another object of the invention is to provide a selective printing machine in which the imprints of selected text sections which are spaced on the printing form, appear in adjacent positions on the surface to which they are transferred.

Another object of the invention is to provide a selective printing machine in which a first surface inked with magnetic ink moves in synchronism with a second surface to which the ink is transferred by a magnetic field, while both surfaces are stopped while the magnetic field is actually effective to transfer the ink.

The magnetic ink which is used in the printing machine and in the method of the present invention, is known, and not an object of the present invention. The ink contains the conventional materials of an offset printing ink and contains between 50 and 70% by weight highly permeable magnetic pigment particles. In accordance with one method of the invention, a magnetic field is produced in a limited area, a magnetic ink is applied to a first surface, and the first surface and a second surface forming a gap with the first surface are moved through the magnetic field which may be produced by direct current or by an alternating current so that the magnetic ink is transferred by the magnetic force from a limited area of the first surface to a corresponding area of the second surface. In one embodiment of the invention, the magnetic ink is transferred from an inking roller only to selective sections of the printing form. In another embodiment of the invention the magnetic ink is transferred 3,376,546 Patented Feb. 27, 1968 from selected sections of the printing form to a copy. In another embodiment, the magnetic ink is transferred from selected sections of the printing form to the blanket of an offset cylinder, and in another embodiment of the invention the magnetic ink is transferred from selected sections of the surface of the blanket of an offset roller to a copy sheet.

In the arrangement of the present invention, no mechanical parts are accelerated, and only the magnetic ink is moved. The starting and stopping of selective printing operations can be consequently carried out at extremely high operational speeds, and the printing cylinder-can rotate at a speed equal to the speed of continuously operating printing machines, whereas conventional selective printing machines require a far lower speed of the printing roller carrying the printing form.

The method of the present invention can be applied to any known printing process. Particularly, electro-photographic and similar printing forms may be used, which produce an adhesive force varying on different image portions and acting on a die powder containing magnetizable particles. i I

In a preferred embodiment of the invention, the ink image is transferred to the rubber blanket of an offset roller, or a magnetic printing form is used. It is advantageous to moisten the printing form so that the electromagnetic means producing the magnetic field can be small while the film of moisture permits a close approach of the surfaces between which the ink in transferred without transfer of magnetic ink by adhesion while the electromagnetic means is not energized.

Magnetic printing foils, standard ofiset foils, or plain carrier sheets may be used. Magnetic printing foils consist of a carrier coated with a layer consisting of a permanently magnetic material and a substance forming a film. The text is produced either by a magnetic stylus, or by irradiation with ultra-red light using the Currie point of the magnetic layer. A standard offset foil is produced in a conventional manner by a typewriter, or by an optical process. Plain carrier sheets receive a text consisting of a highly magnetically permeable, temporarily magnetizalbled ink or die which is manually or by typewriter appie According to the preferred embodiment of the inventron, a printing foil which carries a magnetic image of the text is inked from a spaced inking roller without touching the same by the magnetic field produced by the magnetic image, while the transfer of the magnetic 111k to a foil having a text consisting of a highly permeable, tightly adhering substance, is carried out without engagement of the surfaces by means of a magnetic field produced by an electromagnetic means.

The energization of the electromagnetic means and the control of the magnetic field is obtained by control and selector mean which permit the selection of sections, such as lines or columns, of the text for printing or transfer. A selector key is associated with each section of the text. In a preferred embodiment of the invention, several sets of keys are provided, each set of keys being associated with a column, and the keys of each set respectively associated with lines so that by each key, the part of a line corresponding to a column is controlled.

It will be understood that the term line and column are used interchangeably, and that sets of selector keys can be respectively associated with lines, while each selector key of the set is associated with a column. Selective printing operations of this type have the advantage that invoices can be reproduced with prices and discounts for wholesale dealers, without discounts for retail customers, without prices as delivery notice, and without prices and addresses as warehouse receipts.

The selector means of the machine of the present invention may be controlled by mechanical or electronic program storing devices which store all possible selections, and the number of desired prints for each selection, and then automatically control the machine to print different combinations of text sections in succession while producing for each combination of text sections the desired number of copies.

In accordance with one embodiment of the invention, the control signals of the selector means simultaneously control the advance of the copy sheet. Consequently, the copy sheet is only transported while a selected section of the text is printed thereon, whereas it is at a standstill when undesired sections of the text pass the printing area. As a result, the imprints of the selected sections appear adjacent each other on the copy sheet, although they are spaced on the printing form. For example, the head sec tion of the text, and the few selected lines of work specifications can be printed on a small slip for use as warehouse vouchers, work operations control cards, piecework job cards and similar purposes.

The term magnetic ink is used in this application to describe an ink which will be attracted or repelled by a magnetic force when located in a magnetic field.

The magnetic printing ink used in the machine of the present invention contains the highest possible proportion of magnetic pigment which is bound with a binder material similar to an offset oil which is quickly absorbed by the copy sheet on which the image of the text is to be formed by magnetic transfer and without contact of the ink carrying surface and the imprint receiving surface. The transferred ink will be drawn into the paper of the copy sheet together with the binder material.

The greatest forces act on the magnetic ink when highly permeable magnetic substances are contained in the ink. In order to avoid disturbances of the operation by undesired premagnetization of the ink, its coercive force should be low. However, under certain circumstances it may be advantageous to use pigments which have an average coercive force and residual magnetism. In an alternating magnetic field, the magnetism of these particles is continuously reversed, but the particles retain a substantial residual part of the first magnetization. Consequently, the pigment particles carry out an oscillating movement in the alternating magnetic field which reduces the viscosity of the ink and facilitates transfer by the magnetic field.

A selective printing machine according to one embodiment of the invention comprises electromagnetic means for producing a magnetic field which has a predetermined Width corresponding to a section of a text. Means are provided which have first and second surfaces forming a gap. For example, the surface of the blanket of an offset roller forms a gap with the copy sheet, or an inking roller forms a gap with the surface of the printing form, or the surface of the printing form on a printing cylinder forms a gap with the surface of the blanket of an offset cylinder. Drive means move the first and second surfaces in synchronism through the magnetic field of the electromagnetic means. Selector means control the energization of the electromagnetic means, and preferably include selector keys and selector switches and a rotary contact which rotates in synchronism with the movement of the surfaces.

Moistening means are advantageously provided for moistening the printing form before ink is transferred to the same. In accordance with the invention, the core of the electromagnetic means has a narrow elongated end face of a shape corresponding to the shape of a line of the printing form. Preferably, the core is subdivided into core sections, each of which has a rectangular end face whose shape corresponds to the shape of a line section within a column of the printing form.

In one embodiment of the invention, the printing form is inked, preferably only at selected text sections, and transfers the inked text in the form of a mirror image to the blanket of an offset roller. The inked image of the offset roller is then transferred to the surface of a copy sheet by the magnetic field of an electromagnetic means which is energized only when a selected section of the text on the offset blanket passes the printing area and the electromagnetic means.

In one embodiment of the invention, the printing formv has an inner elastic layer covered by a magnetizable foil. When the printing roller and the offset roller are spaced by a small air gap or hardly touch each other, the magnetic force deforms the printing form so that an actual engagement under pressure takes place between the printing form and the offset blanket which improves the transfer of ink under the action of the magnetic field. Such a deformable printing form permits the transfer of ink even if the same is very little magnetic, or even nonmagnetic.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompariying drawings, in which:

FIG. 1 is a fragmentary cross sectional view illustrating one embodiment of the invention;

FIG. 2 is a' fragmentary axial view illustrating a detail of FIG. 1 on an enlarged scale, and including an electric diagram;

FIG. 3 is a fragmentary cross sectional View illustrating a second embodiment of the invention;

FIG. 3a is a diagram of a modified electric circuit of the embodiment of FIG. 3;

FIG. 4 is a fragmentary cross sectional view illustrating an inking arrangement according to the invention;

FIG. 5 is a fragmentary cross sectional view illustrat ing a modification of the embodiment of FIG. 1, the selector circuit being omitted for the sake of simplicity;.

FIG. 6 is a fragmentary cross sectional view illustrat ing another embodiment of the invention, the selector circuit being omitted for the sake of simplicity; and

FIG. 7 is a cross sectional view illustrating another embodiment parts of which correspond to the construction of FIGS. 1 and 2 and provided with means for stopping the movable parts during the transfer of ink.

Referring now to the drawings, and more particularly to FIGS. 1 and 2 which illustrate a first embodiment of the invention, a printing roller 1 is mounted on a shaft 1a and carries on its peripheral surface a printing form in the form of a thin printing foil which is clamped to the surface of printing roller 1 by a clamping device 2. The printing form may carry a text divided into sections, for example line sections and column sections. The printing form may be attached to the printing roller in such a position that the line sections extend in axial direction, and the column sections extend in circumferential direction of the printing roller.

An inking roll 4 is in rolling engagement with the surfaceof printing form 3, and receives a magnetic ink from a container 6 by means of a doctor roll 5, and a transfer roll 7 which is operated between a position engaging the surface of doctor roll 5 and a position engaging the surface of inking roll 4. Doctor roll 5 may be operated to turn in an intermittent movement.

A moistening roll 8 is partly immersed into a moistening liquid in a container 9 and cooperates with inking roller 4 to apply a moistening liquid in the form of a thin film onto the layer of magnetic ink onroll 4.

This inking arrangement is known, and not an object of the invention. However, in accordance with the present invention, a magnetic ink is used.

An' offset roller 10 is mounted on a shaft 10a, and carries on its peripheral surface, a rubber blanket 12 which is held by a clamping device 11. Rollers 1 and 10 are connected to each other for synchronous rotation by a pair of meshing gears, not shown, and a pulley 13 is fixed to roller and connected by a belt or chain to another pulley 15 which is secured to a control shaft 40.

A supporting table 30 is located below roller 10, and adapted to support copy sheets 192 transported by pairs of transporting rollers 26, 27 and 28, 29. A stack 24 of copy sheets rests on a support 23 which has an inclined guide face leading to transporting rollers 26, 27. An automatic sheet feeding device, not shown, includes a feeding roller 25 resting on the top sheet of the stack and performing a reciprocating motion. During move? ment toward transporting rollers 26,27, roller 25 is blocked so that a sheet is transported, and during the return stroke, roller 25 turns so that the respective upperm'ost sheet is not displaced. A one-Way clutch, not shown, is provided for this purpose.

A box 31 is provided for receiving printed copy sheets after the same are released by transporting rollers 26, 27, and are transported only by transporting rollers 28, 29. Transporting rollers 26 to 29 are connected by a trans.- mission, not shown, with roller 10 so as to be driven in synchronism with the same, and are dimensioned to transport copy sheets 16?. at a speed which is the same as the peripheral speed of the blanket 12 on roller 19. The surface of table Sit, and thereby the copy sheet thereon, are spaced from the surface of the blanket so that a copy sheet transported by the transporting rollers will not be in contact with the surface of the blanket 12.

Support table 30 has a slot or cutout 38a in which core parts 320 to 32 of a core 32 of an electromagnetic means are located. Each core section has a rectangular surface elongated in axial direction, and narrow in circumferential direction of roller 10, and all core sections 32c to 32f extend in axial direction substantially for the entire axial length of blanket 12. In circumferential direction of the roller 10, which is also the direction in which copy sheet 102 is transported, the core 370 to 32d has a predetermined width corresponding to a line section of the printing form 3 and to a corresponding line section of a copy sheet 102, The axial width of each core section 32c to 32 corresponds to the width of a column of printing form 3, and to a corresponding column of a copy sheet 182.

If a printing form is attached to printing roller 1 in the position in which its columns extend in axial direction and its lines extend in circumferential direction, the circumferential width and the axial length of core sections 320 to 32 must be corresponding designed. However, it is preferred to arrange the narrower line sections in the direction of the movement of the copy sheet indicated by an arrow in FIG. 1. I I

The core 32c to 32f is connected by a pair of yoke portions 32a, 32b to the hollow shaft 10a which is secured to stationary frame walls 34. Roller 10 is freely rotatable on shaft 10a, and connected by gears 41, 42 with printing roller 1, as best seen in FIG. 2.

The stationary shaft 10a carries a series of core sections 35:; to 35h which have axial lengths corresponding to the axial lengths of core sections 320 to 32 and a narrow circumferential extension, which, however, may be slightly greater than the circumferential extension of core sections 32c to 32 Windings 33a to 33d respectively surround core sections 320 to 32f, and windings 36a to 36d respectively surround core sections 35e to 35h. Screws 37a to 37d secure annular portions 35a to 35d of core sections 35e to 35] to the stationary shaft 1%.

Each winding 33a to 33d has one end connected by a line 38a to 38d to four lines 18a to 1811', and each winding 36a to 36a has one end connected by lines 39a, 39b, 39c, 39d to lines 18a to 18d. The other ends of each Winding are connected to a main line 22 which together with the other main line 21, is connected to a voltage source.

The direction of the flow of current in windings 33a to 33d, and 36a to 36d, is selected so that the core sections 320 to 32 are south poles, and coresections 35e to 35h are north poles, the magnetic field closing through yoke portions 32a, 32b, shaft 10a, the peripheral wall of the hollow roller 10, blanket 12, and the air gap between a copy sheet Hi2 and the outer surface of'blanket 12, which air gap has a thickness a.

The wall of roller 10 and blanket 12 are made of materials which are highly permeable for the magnetic flux so that a substantially homogeneous magnetic field prevails in the gap between core sections 320 to 32 and blanket 12, and through a copy sheet 102 located in the gap.

Lines 18a to 18d are respectively connected to four rotary contact arms 16a to 16d which are mounted on control shaft 40 to rotate in synchronisrn with roller 10 and transporting rollers 26, 27. Each contact arm is thus correlated with a pair of core sections, for example, contact arm 16a is correlated with a pair of core sections 32c and 352, and consequently also correlated with a column section of a copy sheet 102.

Each rotary contact arm passes successively over a plurality of stationary contacts of which only three contacts 17a, 17b, are shown. The number of stationary contacts in each of the four sets corresponds to the number of line sections of the printing form. Each set of contacts 17a to 170 is connected by conductors 19a to to a set of selector switches 20a, 20b, 20c which are controlled by a set of keys T1, T2, T3.

Consequently, four sets of keys T1 to T3 are provided, each set being correlated with a pair of cooperating yoke sections and with a corresponding column section of the printing form and of the copy sheet. The number of keys in each set corresponds to the number of line sections of the printing form and of the copy sheet, only three keys being shown for the sake of simplicity.

When the machine is started, and drive shaft 1a r0,- tates printing roller 1 with printing form 3 so that roller 10 is driven by gears 41, 42 and transfers its rotary motion through pulleys 13, 15, and belt 14 to the four contact arms 16a to 16d, the same successively and simultaneously engage the correlated stationary contacts of the four sets of contacts 17a to 170. Transporting rollers 26 to 29 rotate, and feeding means 25 starts to operate.

Water repellent portions of printing foil 3 are inked by inking roller 4 in the usual manner, The ink is transferred to the blanket 12 on roller 10 as a mirror image, but cannot form an imprint on a copy sheet 102 because the blanket and copy sheet are not pressed against each other, and are actually spaced the thickness a of the air gap between the copy sheet and blanket 12.

Before the operation was started, selected keys T were depressed, and the corresponding contacts 20 closed.

Assuming first that each key T2 of all four sets of keys was depressed, all windings will be energized when the four contact arms 16a to 16d engage stationary contacts 17b. The arrangement is such that at this moment, a line section of the printing form transferred from the printing form and located on blanket 12, will be located in the gap between core sections 320 to 32 and core sections 35c to 3511.

When the four contact arms engage the four stationary contacts 1% and energize all windings, an electromagnetic field develops in the gap and effects transfer of the magnetic ink from the respective narrow section of blanket 12 to a corresponding line section of copy sheet 102. The preceding inked section and the following inked section of blanket 12 is not printed on copy sheet 102, since the corresponding keys T1, T3 were not depressed, and the corresponding selector switches 20a to 200 remain open.

Assuming that the fourth keys would have been depressed, and corresponding selector switches closed, then ink would be transferred from the respective section of blanket 12 to the fourth line section of the copy sheet.

In the preceding example, it was assumed that all keys T2 of the four sets of keys were operated so that an entire line of the printing form was printed on the copy sheet.

Assuming, however, that only keys of one set of keys were selected and depressed, for example keys connected with stationary contacts 17 engaged by contact arm 16:: then only the pair of core sections 35c, 32c would produce an electromagnetic field since only windings 36a and 33a would have been energized. Consequently, in each selected line section, only one column section would have been printed.

It is evident that by selection and operating of selected and different keys T of the four sets of keys, one or several selected column sections of one or several selected line sections can be imprinted on the copy sheet.

In order to accomplish this result, it is necessary that the magnetic field produced by the electromagnetic means has in the direction of movement of copy sheet 102 a predetermined Width corresponding to a text section, preferably a line section, of the printing form and of the desired imprint, and in a direction transverse to the direction of movement, a length which may correspond to the entire length of a line, or only to the width of a column of the text.

Referring now to the embodiment of the invention illustrated in FIG. 3, a printing cylinder 1 is mounted on a shaft 1a and carries a printing form 3 which is inked by an inking device 4 to 9 as described with reference to FIG. 1. An offset roller 10 has a blanket 12 to which a mirror image of the text of the printing form consisting of magnetic ink is transferred. Transporting rollers 26, 27 receive copy sheet blanks from a stack 24 when the feeding device is operated to reciprocate roller 25, as described with reference to FIG. 1. The copy sheet 102 is gripped by a gripping means 46 on a magnetizable roller 47 which is mounted on a shaft 48. A stationary cam, not shown, controls gripper means 46 in a conventional manner to cause gripper means 46 to grip the leading edge of copy sheet 102 at the proper moment, and to release the same again when the leading edge approaches a transporting roller 51 cooperating with a slanted guide plate 50 so that a printed copy sheet is discharged along guide plate 50 and drops onto a support 31. An eccentric member 49 is secured to magnetizable roller 47 and to shaft 48, and reciprocates the feeding device 125 together with roller 25.

At the beginning of rotation of roller 47, a copy sheet 102 is transported into the open gripper means 46 which close to further transport the copy sheet until the same is delivered to discharge roller 51.

Rollers 1 and 10 are connected by a gear transmission, not shown, for rotation in synchronism. Rollers 10 and 47 are driven by common drive means 52 from which also the drive of rollers 1 and 10 is derived. In the position illustrated in FIG. 3, rollers 10 and 47 are disconnected from drive means 52.

Drive means 52 includes a friction wheel 52a cooperating with friction wheels 54 and 56. Friction wheel 54 is connected with roller 47 by pulley and belt means 53, while friction wheel 56 is connected with roller 10 by pulley and belt means 55.

Friction wheel 54 is turnably mounted on a pivot means provided on a lever 57 which is mounted on shaft 48 for angular displacement, and friction wheel 56 is turnably mounted on a pivot means provided on a lever 58 which is mounted on shaft 10a for angular displacement. A spring 61 acts on lever 57 to press brake wheel 54 against a brake block 63, and a spring 62 acts on lever 58 to move friction wheel 56 away from a friction block 64 and into engagement with a blocking lever 66 which is mounted on a pivot means 65 and urged against portion 58a by a spring 67. A release lever 68 is mounted on a pivot 69 and biased by a spring 70 to abut a fixed stop 71a.

Electromagnetic means 59 and 60 have movable armatures respectively articulated to levers 57 and 58 so that upon energization of electromagnetic means 59 lever 57 is turned in counterclockwise direction to a position in which friction roller 54 no longer engages brake block 63 but is coupled with friction wheel 52a of drive means 52 so that the roller 47 is rotated by pulley and belt means 53. When release lever 68 is manually operated, blocking lever 66 releases engaging portion 58a, as Spring 62 moves friction wheel 56 into coupling engagement with friction wheel 52a so that roller 10 is rotated by pulley and belt means 55. Energization of electromagnetic means 60 will move lever 55 from this position to a position in which friction wheel 56 is braked by brake block 64 while blocking lever 66 snaps under engaging projection, 58a which is facilitated by slanted engaging faces on portion 58a and on blocking lever 66. Roller 10 can only rotate after manual operation of release lever 68.

Blanket 12 is separated from copy sheet 102 and from roller 47 by an air gap having the thickness a so that the surface of the copy sheet is not engaged by the surface of the blanket.

Roller 47 has a series of peripheral cores 47 spaced in circumferential direction by narrow gaps. Each core section 47 may extend for the entire axial length of roller 47 corresponding to the length of a line of the printing form and of the copy sheet, and be surrounded by a single winding 47a, or each core 47 may be divided into a plurality of axially adjacent core sections, each surrounded by a winding and having an axial length corresponding to the width of a column, substantially as described with reference to the stationary cores 320 to 32] of the embodiment of FIGS. 1 and 2.

A pulley and belt drive 14, 15 connects roller 10 with four contact arms 16a to 16d which are respectively associated with four axial magnet core sections of the cores 47. Each contact arm cooperates with a set of stationary contacts, of which only one set comprising three contacts 17a, 17b, 170 is shown in FIG. 3. Conductors 19a, 19b, 19c connect each set of stationary contacts 17a, 17b, 170 with selector switches 20a, 20b, 20c which are controlled by keys T1, T2, T3. The number of sets of keys T1, T2, T3 corresponds to the number of axial core sections of cores 47', and the number of selector switches and stationary contacts corresponds to the number of lines of the printing form and of the copy sheet.

The four windings on the four axial core sections of each core 47" are wound so that alternating cores 47' are energized in opposite directions whereby north poles and south poles of cores 47' alternately pass through the printing line.

Each winding 47a is connected by a conductor 72, a slide contact 76, and a contact ring on shaft 48 engaged by slide contact 76 with a corresponding set of selector switches 20a, 20b, 20c and by the same to the corresponding stationary contacts 17a, 17b, 17c, and also by a conductor 77 to one end of the winding of electromagnetic means 59. The other ends of windings 47a to 471 are connected to the insulated peripheral contact sections of a commutator. The contact sections of the commutator are again divided into four contact parts which are respectively engaged by four slide contacts which are connected to a main line 22 which, together with main line 21, is connected to a source of voltage.

Due to the provision of the commutator, only adjacent cores 47' located in the region of the gap between roller 47 and roller 10 with blanket 12, are energized and produce a magnetic field with lines of flux flowing through the gap from core 47 magnetized to be a north pole to the adjacent core 47 magnetized to be a south pole. In this manner, a magnetic field is produced in the gap and causes transfer of magnetic ink from blanket 12 to copy sheet 102. If all four sections of two adjacent cores 47 are magnetized in opposite sense, an entire axially extending line will be transferred to the copy sheet, but if only one or several pairs of core sections are energized due to corresponding selections of keys from several sets, the transferred text sections will have an axial extension corresponding to the axial extension of the respective core sections, and parts of lines'located in selected columns will be printed.

Before printing of a copy sheet takes place, the operator selects certain sections of the printing form for printing by depressing selected keys T and closing the corresponding selector switches 29. It will be understood that either selected switches of each of the four sets of switches, or the same switch in all four sets may be actuated. In the latter case, all four keys T2, for example, are depressed so that the entire second line is printed in all four columns.

Electromagnetic means 59 is connected by line 77 not only to lines '72 and the four slide contacts 76, but also to the four sets of selector switches 20, and to line 87' leading to a first switch contact 83. The second switch contact 84 is connected by a line 88 to one end of winding 60. The respective other ends of windings 59 and 60 are connected to main line 22 to which slide contact 75 is connected.

Keys T and selector switches 20 are again associated with sections of the printing form, and corresponding contacts 17 will be engaged by a contact 79 when the respective section on blanket 12 passes through the gap between the blanket and to adjacent cores 47' of roller 47.

A contact 79 is connected by line 81 to a contact cooperating with switch contact 84, and a second contact 80 is connected by a line 82 to another contact cooperating with switch contact 83. Switch contacts 83 and 84 are operated by a cam follower 85 cooperating with a cam projection 86 of a cam rotating in synchronism with roller 47. Contacts 79, 80 are connected by contact arm 16.

During the operation, the entire text of a printing form 3 on roller 1 is transferred to blanket 12 in the form of a mirror image. The operation is started by operating release lever 68 so that spring 62 couples friction wheel 56 with drive wheel 52a. Electromagnetic means 60 is not energized when switch contacts 83, S4 interrupt the connection. Electromagnetic means 59 is energized and moves lever 57 to a position in which friction wheel 54 is coupled with the drive wheel 52:: so that roller 47 rotates in synchronism with roller whereby the copy sheet is moved by gripper 46 at the same speed as blanket 12. Whenever a contact arm 16 passes over a contact 17 selected by actuation of the respective key and selector switch 20, the respective windings are energized to attract the ink of a section of blanket 12 and to transfer the ink to a corresponding section of copy sheet 102. When contact means 16, 17 interrupts the circuit, electromagnetic means 59 is de-energized, the friction coupling 52a, 54a is interrupted, spring 61 presses friction wheel 54 against brake block 63, and roller 47 is momentarily stopped while roller 1%) with blanket 12 continues to rotate with those sections of the printed text which are not selected for being imprinted on the copy sheet. When a contact arm 16 again engages a stationary contact 17 selected by closing of the respective selector switch 20, electromagnetic means 59 is again energized so that coupling 52a, 54 is again engaged, roller 47 rotates, and gripper 47 moves the copy sheet at the same speed as the blanket, while a magnetic field is produced in the gap to transfer another selected section of the text from blanket 12 to copy sheet 102 where an imprint will appear directly adjacent the preceding imprint since roller 47 was at a standstill while roller 10 and blanket 12 turned from the first selected section to the second selected section.

When rollers 1 and 10 have performed one complete revolution, contacts 79, 80 are connected by contact arm 16. Switch contacts 83, 84 are in the closed position so that electromagnetic means 60 is energized and moves lever 86 with friction wheel 56 away from drive wheel 52a so that friction wheel 56 is braked by brake block 64 and rolier 10 and printing roller 1 are stopped. At the same time, electromagnetic means 59 is energized, and

friction wheel 54 is drawn into engagement with drive wheel 52 whereby roller 47 is rotated. Since feeding device 125 and discharge roller 51 are driven from roller 47, the printed copy sheet is transported until engaged by roller 51 and deposited on support 31. At the same time, a new copy sheet is inserted into the open gripper 46 which closes to hold the new copy sheet.

At the moment in which a second copy sheet is ready to be printed, follower roller of switch contacts 83, 84 is engaged by cam portion 86 which moves in synchronism with roller 47, so that the circuit of electromagnetic means 59, 60 is interrupted. Spring 61 pulls friction wheel 54 against brake block 63 and stops roller 47 until electromagnetic means 59 is energized again when a contact 17 is engaged by the contact arm. Movement of lever 58 under the action of spring 62 is blocked by blocking lever 66 until release lever 68 is again operated which starts the next operational cycle in which the same selected sections are printed. However, before the next actuation of release lever 68, a new series of sections of the printing form can be selected by clearing selector switches 29, and operation of other keys T.

The diagram of FIG. 3a shows substantially the circuit of the embodiment of FIG. 3, modified by the addition of a relay 138 controlling electromagnetic means 59 by operating switch 131 in a line 130. Relay 133 is energized by a slide contact 134 in line 132 when one of the circuits 76a to 76d is closed. Since relay 133 responds even if contacts 16a, 79 are closed, switch contact 83 can be omitted.

In the embodiment of FIG. 4, a printing roller 92 is mounted on a shaft and carries a magnetic printing form 91 which is in rolling contact with a moistening roll 8 partly immersed into a liquid in a container 9. A magnetiza'ble roller 93 is mounted on a shaft 96 and has a peripheral surface defining a gap with printing form 91. Roller 93 serves as an inking roller and is in contact with an amount of magnetic ink 95 accumulated between the peripheral surface of roller 93 and an applicator plate 94 whose position can be adjusted by an adjusting screw 101 screwed into the support of applicator plate 94. During rotation of roller 93, a thin film of ink forms on its peripheral surface. Roller 93 is connected by transmission means with printing roller 92 so that printing form 91 and the peripheral sunface of roller 93 move at the same speed. The periphery of roller 93 is formed by cores 9311 which are separated by gaps 93a, and surrounded by windings 930. The construction of roller 93 corresponds to the construction of roller 47 of FIG. 3, and the cores 93b may the divided into axial sections. Assuming that each core 93b extends over the entire axial length of roller 93 corresponding to the axial length of printing form 91, the windings 93c of adjacent cores 93b are energized in opposite directions so that adjacent cores 93b form north poles and south poles, respectively on the periphery of roller 93 whereby a magnetic field is formed in a narrow region of the gap substantially in a printing plane passing through the axes of shafts 90 and 96.

Shaft 96 of roller 93 is connected by the slide contact and conductor 98 with the main line 22 of a source of direct current. The windings 930 respectively have one end connected to mass and to shaft 96 and main line 22, and other ends respectively connected to the contacts of a commutator 99 rotating with roller 93 and in sliding engagement with a slide contact 100 connected by a line 18 to a rotary contact arm 16 which rotates in synchronism with printing roller 92, and is connected to the same by transmission means, not shown, substantially as described with reference to FIG. 1. Contact arm 16 successively engages stationary contacts 17a, 17b, which are associated with circumferentially adjacent axially extending elongated line sections of printing form 91, only three stationary contacts being shown to represent a far greater number of stationary contacts correlated to line section.

Each stationary contact is connected by conductors 19a, 19b, 190 to selector switches 20a, 20b, 200 which are selectively operated by keys T1, T2, T3. The selector switches are also connected to the second main line 21 and thereby to the voltage source.

During operation, rollers 93 and 92 are rotated. When a selected section of the printing form 91 is located in the printing plane and in the gap, contact arm 16 either engages a contact 17 whose switch 20 is not closed, or a contact 17 whose switch 20 is closed since the operator depressed the respective key T to select the respective section of the printing form for inking.

If the selector switch 20 associated with the respective section of the printing form located in the printing plane is open, the respective windings are not energized, and no magnetic field is produced in the gap.

However, if a selector switch 20 is closed when the corresponding section of the printing form 91 passes through the printing plane, then the circuit of the responsive winding which at this moment approaches the gap and the printing plane is closed by engagement of contact arm 16 with the respective contact 17, so that a magnetic field is produced in the gap.

During rotation of rollers 92 and 93, the thin film of magnetic ink on the peripheral surface of roller 93 is attracted by the magnetic printing form 91 and transferred to the same. However, the ink can only adhere to those portions of the magnetic printing form 91 which were made permanently magnetic while the image of the text was produced on printing form 91. Consequently, the text portions of the printing form are continuously inked. However, when the rotary contact arm 16 engages a contact 17 whose selector switch 20 was closed by operation of the respective selector key T, the winding 930 of a core 93b approaching the printing plane is energized so that a magnetic field is produced in the gap. The windings and cores are designed so that the magnetic field is opposed to the field produced by the magnetic printing form 91 and compensates the same. Consequently, the ink on the peripheral surface of roller 93 is not attracted to the printing form, and since the same has a thin film of liquid, no ink at all adheres to the printing form in the respective text section which is narrow in circumferential direction corresponding to a narrow magnetic field produced by the respective cores 93b.

Only selected sections of a printing form 91 are inked in this manner, while non-selected sections are not inked. It is evident that the printing form inked in this manner can be used in conventional printing apparatus for printing on a copy sheet only the selected and inked sections.

However, a printing apparatus substantially corresponding to the embodiments of FIGS. 1 or 3 may also be used, in which event the printing form would be attached to printing roller 1, or directly to the periphery of roller 10, and a corresponding selection is carried out by operation of the selector keys so that the ink is transferred from the inked sections of the printing form by magnetic attraction across an air gap and onto a copy sheet, whereby a smudging of the copy sheet between selected and printed sections is reliably prevented, since no pressure has to be applied by the printing form on the copy sheet. Also, a deposit of superfluous ink on lines which are not to be printed can be reliably avoided by transferring the ink from selected sections of the printing form by a magnetic field in accordance with the invention.

In the embodiment of FIG. 5, a printing cylinder 1 carries a printing form 3 which is inked with magnetic ink by a printing device 4 to 9. A roller rotates in synchronism with printing roller 1 and carries a blanket 12 to which a mirror image of the text of the inked printing form is transferred. Transporting rollers are provided for transporting a copy sheet 102, as described with reference to FIG. 1.

A narrow magnetic field is produced by a horse-show magnet 103 whose north and south poles are located directly below a transported copy sheet 102 and are closely spaced from each other to form a narrow air gap 103a. Air gap 103a extends over the axial length of the blanket 12 and over a narrow section in the direction of movement of the copy sheet. The shape of air gap 103a is such that the flux lines pass through the gap between copy sheet 102 and blanket 12, permeating the latter which is made of a rubber material which has a high magnetic permeability.

The magnetic field consists of two substantially homogeneous halves which causes transfer of ink from a narrow section of the blanket corresponding to a text section of the printing form to a corresponding section of the copy sheet 102. Rotary contact means and selector switches as described with reference to FIG. 1 are connected to the winding of electromagnetic means 103, but not shown for the sake of simplicity.

In the embodiment of FIG. 6, a printing roller 1 carries a printing form 107 inked by an inking device 4 to 9 and spaced by a gap from a roller 10 carrying a blanket 12. A stationary electromagnetic means 104 is mounted in the interior of printing roller 1, and a corresponding stationary electromagnetic means 35' is mounted in offset roller 10. The arrangement corresponds to the construction of electromagnetic means 32 and 35 described with reference to FIG. 1, and corresponding rotary contact means and selector switches are provided, although not shown in FIG. 6. It is evident that cooperating electro magnetic means 35 and 104 will produce a magnetic field whenever energized whereby the ink forming the text on printing form 108 is transferred to the surface of blanket 12.

A stack of copy sheets 24 is provided on a support, and the copy sheets are successively fed by a feeding roller 25 to transporting rollers and to an automatically opening and closing gripper 105 on a roller 106, substantially as described with reference to roller 47 of the embodiment of FIG. 3. Roller 106, however, is not a magnetizable roller and has no magnetic windings.

Roller 105 serves as a conventional counterpressure roller exerting pressure against the copy sheet and the blanket 12 of offset roller 10.

Printing form 107 which is secured by a clamping means 2, has an inner layer 10% consisting of an elasticsheet, which may consist of foam material. Printing form 107 is made of a magnetizable material, which may be a magnetizable metal, or a synthetic plastic material in which highly permeable magnetizable particles are embedded.

When electromagnetic means 104 and 35' are energized, a magnetic field is produced in the gap between the printing form and the blanket, exerting a magnetic force on the magnetizable foil 107 producing a deformation of the elastic layer 108 and a bulge in the printing form. In the illustrated construction, magnets 35' and 104 have substantially the same distance from printing foil 107. In order to draw a portion of the printing foil 107 in a direction toward blanket 12 for reducing the air gap a between the blanket and the printing form, the permeability of the rubber blanket 12 and of roller 10 should be greater than the permeability of printing cylinder 1. When the bulge of the printing form is pressed by the magnetic force against the surface of the blanket, an imprint is made even if the ink is not magnetic.

A magnetic cleaning device is provided for removing the inked image from blanket 12 after each revolution of the same so that a new image can be transferred from the printing form 107 in accordance with another selection carried out by operation of keys and closing of selector switches, as described with reference to FIG. 1.

The cleaning device includes a permanently magnetic roll 128 which is driven to rotate in synchronism with roller 10 by transmission means, not shown. The periph eral surface of cleaning roller 128 is spaced by an air gap having a thickness b from the surface of blanket 12. The

13 permanent magnet poles of cleaning roller 128 are schematically indicated by the letters N and S representing north pole and south pole, respectively. It is preferred to construct cleaning roller 28 of thin magnetized discs of which alternating discs have north poles and south poles, respectively. The ink on blanket .12 is attracted by cleaning roller 128, scraped off by a scraper 12-9 and deposited in a container 130.

During operation of the printing machine shown in FIG. 6, ink is transferred from selected sections of the printing form 107 whenever electromagnetic means 35, 104 are energized in accordance with a selection carried out by the operator as described with reference to FIGQ 1. Only selected text sections appear circumferentially spaced from each other on blanket 12, and are imprinted on the copy sheet due to the printing pressure applied by counter-pressure roller 106. When the surface of the blanket is cleaned by cleaning roller 128 by magnetic attraction of the ink thereon, the next selection is made by the operator, and other text sections are transferred to the blanket surface and then printed on a copy sheet.

Referring now to the embodiment of FIG. 7, a printing cylinder 1 carrying a printing form with axially extending elongated line sections is mounted on a shaft 1a and is connected by gears, not shown, to an offset roller which is turnable about a stationary shaft 10a and carries a blanket 12. An inking device 4 to 2, as described with reference to FIG. 1, inks the printing form with magnetic ink so that during rotation of rollers 1 and 10, a mirror image of the text of the printing form is transferred to blanket 12. A support table and an electromagnet 32 in a slot of the same, form a supporting surface along which a copy sheet is transported by pairs of transporting rollers 26, 27 and 28, 29' from a table 124 to a box 31.

The copy sheets are manually placed on table 24 held against a movable stop member 125 which is mounted for pivotal movement and has a cam follower portion 125a cooperating with a cam-126 on roller 10 so that when the text on blanket 12 is so positioned that a new copy sheet has to be fed, stop member 125 is pivoted against the action of a spring to a position permitting manual shifting of copy sheet 102 into the bight between transporting rollers 26, 27 which further transport the copy sheet into the gap between the core of electromagnet 32 and blanket 12.

The construction of electromagnets 32 and 35 is as described with reference to FIGS. 1 and 2. The cores of electromagnets 32 and 35 may be subdivided in axial direction corresponding to the columnsof the text, but for the sake of simplicity it may be assumed that the cores of electromagnets 32 and 35 have anarrow elongated shape corresponding to a line section of the printing form and of the transferred image on blanket 12.

Pulley and belt means 14' connect printing roller 1 with a rotary contact arm 16 so that the same turns in synchronism'with rollers 1 and 10 and successively passes over a plurality of stationary contacts 17 whose number and positions correspond to the number and positions of the line sections of the printing form, only three stationary contacts 17a, 17b, 170 being shown for the sake of simplicity. Contacts 17a, 17b, 170 are respectively connected by selector- switches 20a, 20b, 200 to the main line 21 which, together with main line 22, is connected to 9. voltage sourcefSelector keys T, of which only selector keys T1, T2, T3 are shown for the sake of simplicity, can be operated to selectively and individually close selector switches '20.

The arrangement is such that when contact arm 16 engages a stationary contact 17, the transferred image of a corresponding line section of the printing form is located in the narrow gap between blanket 12 and the end face of the core of electromagnet 32.

Contact arm 16 is also connected to a lever arm 118 pivotally mounted on a journal 117 and normally urged by a spring 119 toa position abutting a stop 120. A contact 122 on lever arm 118 cooperates with a stationary contact 121 which is connected to one end of the winding of an electromagnetic means 127, and to one end of the winding of electromagnet 32.

Contact arm 16 is also connected to one end of the winding of an electromagnetic means 115. The second ends of electromagnetic means 127, 32, and 115 are all connected to the second main line 22.

Consequently, electromagnetic means 115 will be energized when contact arm 16 engages any one of stationary contacts 17 whose correlated selector switch 24 is closed.

On the other hand, electromagnetic means 127 and 32 will also require closing of contacts 121, 122 for ener gization.

Drive means 52 include a friction wheel 52: which cooperates with a friction wheel 56 mounted on a lever 58. and connected by pulley and belt means 55 with roller 10 so that the same is rotated in the position of FIG. 7 and drives through gears, not shown, printing roller 1 from which the rotation of contact arm 16 is derived.

A spring 62 urges lever 58 to the position in which the rotary elements rotate. A control lever 110 has an engaging portion cooperating with portion 169 of lever 58 while abutting a stop 114 under the action of a spring 113. Lever 110 is articulated to the armature of electromagnetic means 127 by a lost motion connection.

Electromagnetic means 115 has an armature connected to a. lever which is mounted on a stationary pivot 111 and articulated to lever 114 Lever 118 which carries contact 122 has a brake block 116 adapted to cooperate with friction wheel 56. In the normal position illustrated in FIG. 7, friction wheel 56 is spaced from brake block 116 and rotated by drive wheel 52a.

An adjusting screw 123 in a stationary frame part can be used for adjusting the exact distance between contacts 121 and 122 since contact 121 is mounted on a resilient arm.

When a printing operation is to be started, the operator selects desired line sections of the printing form for printing. All other line sections are omitted. The selection is carried out by depressing selected keys T, each key being associated, for example by indica, with a line section of the printing form. For example, key T1 may be associated with the head section of the printing form, key T2 with the first line, key T3 with the second line, and so forth. It may be assumed that keys T1 and T2 are depressed, and key T3 is left open.

When drive means 52 of the machine are started, for example by. switching on a motor, not shown, friction Wheel rotates and transmission 55 transmits the rotation to roller 10 which drives printing roller 1 through a transmission, not shown, so that contact arm 16 is rotated by transmission 14', The printing form is inked by inking roller 4, and the text thereon transferred to blanket 12. When the portion of blanket 12 carrying the transferred image of the head section of the printing form approaches the gap between the blanket and electromagnetic means 32, contact arm 16 approaches contact 17a. When contact arm 16 engages contact 17a, electromagnetic means 115 is connected to the voltage source 21, 22 since selector switch 20a is closed. The armature of electromagnetic means 115 turns lever 112 and moves control lever downward as viewed in FIG. 7 which is possible due to a pin and slot connection between control lever 110 and the armature of electromagnetic means 127.

The transverse projection of control lever 11%) moves engaging portion 101 of lever 58 downward so that friction wheel 56 is separated from drive friction wheel 52a and moved into engagement with brake block 116 whereupon lever 58 is further moved while turning about shaft 10a until lever 118 has been turned againset the action of spring 119 to a position in which contact 122 engages contact 121. I 1

At the moment of engagement between friction wheel 56 and brake block 116, rotary members 10, 1 and 16 are braked, and the position of contact 121 was adjusted by adjusting screw 123 so that the rotary elements stop when contacts 122, 121 engage each other and close the circuit of electromagnetic means 32 and 35, the winding of electromagnetic means 35 being connected in parallel with the winding of electromagnetic means 32 as described with reference to FIG. 2.

At this moment, roller 10 is stopped with the portion of blanket 12 carrying the desired head section of the text located directly opposite the axially elongated narrow end face of the core of electromagnetic means 32, and between the same and the correspondingly shaped end face of the core of electromagnetic means 35.

Since the circuit of electromagnetic means 32, 35 is closed by contacts 121, 122, a magnetic field is produced in the gap permeating the blanket and the wall of roller 10, and magnetically attracting the magnetic printing ink so that the same is transferred from the blanket to the 'copy sheet covering the end face of the core of electromagnetic means 32. Due to the narrow and elongated shape of the cores of the electromagnetic means 32 and 35, only ink representing the text of the respective selected line section is transferred to the copy sheet. Since roller 10 is stopped, the outline of the section is precisely maintained.

At the same time, electromagnetic means 127 was connected to the voltage source by the closed contacts 121, 122 and the armature of electromagnetic means 127 turns lever 110 from the position holding friction wheel -6 on the surface of the brake block 116 in clockwise direction to a position in which the transverse projection of control lever 110 releases engaging portion 109 of lever 58 so that spring 62 turns lever 58 back in counterclockwise direction. Friction wheel 56 is first disengaged from brake block 116 so that spring 119 returns lever arm 118 to the position abutting stop 120 in which contacts 121, 122 are separated causing de-energization of electromagnetic means 32, 35 and 127 so that spring 113 can return control lever 110 to the normal illustrated position. Thereupon friction wheel 56 moves further under the action of spring 62 into engagement with drive 'wheel 52a.

Rotation of the rotary members is again started, and since transporting rollers 26, 27 are also connected by transmission means, not shown, with roller 10, the copy sheet is transported to a position in which its first line section is located in the gap. At this moment, contact arm 16 engages stationary contact 17b so that the circuit of electromagnetic means 115 is completed through the closed selector switch 20b. The operations described with reference to the head section of the text are repeated, and the first line of the text is printed adjacent the head section while roller 19 is at a standstill. Thereupon the rotary part start again to turn after engagement between friction wheel 56 and drive friction wheel 52a and since contact 170 is not connected to the voltage source 21 since selector switch 20c is open, roller is not stopped, and the inked image of the second line of the text passes electromagnetic means 32, 35 without being printed.

From the above descriptions of several embodiments of the invention, it will become apparent that in all embodiments of the invention, two surfaces forming a gap :move at the same speed, including zero speed correspond .ing to standstill of the surfaces while magnetic ink is transferred from one surface to the other surface by a magnetic field. Selector means, preferably including selector keys and selector switches associated with sections of the printing form, which may be line sections or column sections, cause energization of the electromagnetic means producing the magnetic field whenever a desired section of the text passes the printing line where the electromagnetic means producing the magnetic field is located. The selec- .tion may also be carried out by magnetically compensating a constant magnetic field which transfers ink from one surface to the other surface except when compensated at selected points by a selectively produced opposing magnetic field.

It will be understood that each of the elements de scribed above, or two or more together, may also find a useful application in other types of printing machines differing from the types described above.

While theinvention has been illustrated and described as embodied in a method and apparatus for selective printing in which magnetic is transferred by a magnetic field to produce imprints only of selected sections of the printing form on a copy sheet, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to'be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A selective printing machine comprising, in combination, a set of electroma-gnets disposed in a row for producing, when energized, narrow magnetic field sections having in a direction transverse to said row the same narrow predetermined width corresponding to the Width of a line, and having in the direction of said row a length corresponding to the width of a column of a text to be printed; first means having a first surface; second means having a second surface forming a gap with said first surface; means for applying a 'magnetizable ink to said first surface so that said ink forms text sections having said predetermined width on corresponding surface sections; drive means for driving said first and second means for moving said surfaces in said transverse direction in synchronism through said magnetic field; means for energizing selected electromagnets only when selected sections of said surfaces pass through said magnetic field so that the same control the transfer of ink from a section of said first surface having a length corresponding to the length of at least one magnetic field section and said predeter-. mined width, to a corresponding section of said second surface whereby only text sections selected by energization of .said electromagnetics and having said predetermined Width corresponding to a line, and a length corresponding to the width of a column are transferred; and electric circuit means for connecting said electromagnets with a voltage source, and including a set of first and second cooperating contact means of which said first contact means is driven in synchronisrn with said first and second means and With said surface, each second contact means including a plurality of stationary contacts connected with each said electromagnet, respectively; and a set of pluralities of selector switches respectively correlated with line sections, said sets of pluralities of selector switches being respectively connected with said sets of first and second contact means, said selector switches of each set being respectively connected with said stationary contacts and selectively operable for causing energization of selected electromagnets only when line sections selected by operation of selected selector switches pass through magnetic field sections selected by operation of selector switches so that said electromagnets transfer ink from at least one selected line and column area of said first surface to a corresponding area of said second surface.

2. A printing machine as set forth in claim 1 including a printing roller for carrying a printing form; and wherein said first means include an offset roller and a blanket on the same cooperating with said printing form and having said first surface; and wherein said second means include transporting means and supporting means for a copy sheet having said second surface.

3. A printing machine as set forth in claim 1 including a printing roller for carrying a printing form; and wherein said first means include an offset roller and a blanket on the same cooperating with said printing form and having said first surface; and wherein said second means includes a roller carrying said electromagnetic means and including means for gripping and transporting a copy sheet having said second surface.

4. A selective printing machine comprising, in combination, electromagnetic means for producing, when energized, a magnetic field having in a given direction a predetermined Width corresponding to a section of text to be printed; first means including a roller having a first surface; second means having a second surface forming a gap with ,said first surface; means for applying a magnetizable ink to said first surface so that said ink forms text sections having said predetermined width on corresponding surface sections; drive means for driving said first and second means for moving said surfaces in said given direction in synchronism through said magnetic field; means for energizing said electromagnetic means only when selected text sections pass through said magnetic field, and for deenergizing said electromagnetic means when non-selected text sections pass the same so that the same controls the transfer of ink of each selected text section on a section of said first surface having said predetermined width to a corresponding section of said second surface whereby only text sections selected by,

energization of said electromagnetic means and having said predetermined width are transferred; said electromagnetic means comprising a first electromagnetic means including a first core having an end face forming said gap with said first surface of said roller and being narrow in said given direction, and a second electromagnetic means located in said roller and having a second core with an end face narrow in said given direction and confronting said end face of said first core, said first and second electromagnetic means being stationary so that said first and second surfaces move between said end faces.

5. A selective printing machine as set forth in claim 4 wherein said first and second cores each comprise a plurality of core sections, and including a winding around each of said core sections, and means for selectively en ergizing the winding of pairs of core sections of said first and second cores.

6. A selective printing machine comprising, in combination, electromagnetic means for producing, when energized, a magnetic field having in a given direction a predetermined 'wid th corresponding to a section of text to be printed; first means having a first surface; second means having a second surface forming a gap with. said first surface; means for applying a magnetizable ink to said first surface so that said ink forms text sections having said predetermined width on corresponding surface sections; drive means for driving said first and second means for moving said surfaces in said .givendirection in synchronism through said magnetic field; means for energizing said electromagnetic means only when selected text sections pass through said magnetic field, and for deenergizing said electromagnetic means when nonselected text sections pass the same so that the same controls the transfer of ink of each selected text section on a section of said first surface having said predetermined width to a corresponding section of said second surface whereby only text sections selected by energization of said electromagnetic means and having'said predeter mined width are transferred; said electromagnetic means comprising a horse shoe magnet having closely spaced north pole and south pole end portions forming in the region of said gap a narrow magnetic field passing through said surfaces.

7. A selective printing machine comprising, in combination, electromagnetic means for producing, when energized, a magnetic field having in a given direction a predetermined width corresponding to a section of text to be printed; first means having a first surface; second means having a second surface forming a gap with said first surface; means for applying a magnetizable ink to said first surface so that said ink forms text sections having said predetermined width on corresponding surface sections; drive means for driving said first and second means for moving said surfaces in said given direction in synchronism through said magnetic field; means for energizing said electromagnetic means only when selected text sections pass through said magnetic field, and for deenergizing said electromagnetic means when nonselected text sections pass the same so that the same controls the transfer of ink of each selected text section on a section of said first surface having said predetermined width to a corresponding section of said second surface whereby only text sections selected by energization of said electromagnetic means and having said predetermined width are transferred and comprising means for stopping movement of said first means; and control means controlling said stopping means and said means for energizing said electromagnetic means so that said first surface is at a standstill when said electromagnetic means are energized and ink is transferred from said first surface to said second surface.

8. A selective printing machine comprising, in combination, electromagnetic means for producing, when energized, a magnetic field having in a given direction a predetermined width corresponding to a section of text to be printed; first means including a roller having a first surface; second means having a second surface forming a gap with said first surface; means for applying a magnetiza ble ink to said first surface so that said ink forms text sections having said predetermined width on corresponding surface sections; drive means for driving said first and second means for moving said surfaces in said given direction in synchronism through said magnetic field; means for energizing said electromagnetic means only when selected text sections pass through said magnetic field, and for deenergizing said electromagnetic means when non-selected text sections pass the same so that the same controls the transfer of ink of each selected text section on a section of said first surface having said predetermined width to a corresponding section of said second surface whereby only text sections selected by energization of said electromagnetic means and having said predetermined width are transferred; wherein said second means is a copy sheet; comprising transporting means for said copy sheet; wherein said drive means include a drive shaft and a coupling between said drive shaft and said roller, spring means for holding said coupling in an engaged position, transmission means con necting said roller with said transporting means; means for braking said roller in the disengaged position of said coupling; means for shifting said coupling from said engaged position to said disengaged position when a selected section of the text on said first surface passes through said magnetic field so that the roller and said first surface are braked and stopped during the transfer of ink from said first surface to said second surface; and switch means in the circuit of said electromagnetic means closed in said disengaged position of said coupling for energizing said electromagnetic means only when said roller is stopped.

9. A selective printing machine comprising, in combination, a roller having a first peripheral surface; means for applying a magnetic ink to said first surface in the form of an inked mirror image of a text having sections; drive means including a rotary friction wheel; a control switch having a movable arm; a brake block on said movable arm; a spring urging said movable arm and said brake block to a normal position of rest in which said control switch is open; a movable coupling member having a rotary friction wheel located between said drive wheel and said brake block, and being shiftable between a position in which said friction wheel is driven, and a position in which said friction wheel is braked and stopped by said brake block; transmission means connecting said friction wheel with said roller for rotating the latter; transporting means for transporting a copy sheet having a second surface in a given direction along a path so that said first and second surfaces form a gap; means connecting said transporting means with said roller for synchronous rotation so that said first and second surfaces move in synchronism; electromagnetic means located along said gap and having core means narrow in said direction for producing, when energized, a magnetic field having in said direction a predetermined width corresponding to a section of the text; first and second cooperating contact means of which one contact means is driven from said roller in synchronism with the same, said first contact means including a contact arm, and said second contact means including a plurality of contacts successively engaged by said contact arm during rotation of said one contact means; a plurality of selector switches respectively connected with said contacts; a contact on said movable arm of said control switch being connected with said contact arm, and another contact of said control switch being connected with said electromagnetic means; a first control magnet connected with said control arm to be energized in positions of said first and second contact means determined by selected closed selector switches, said first control magnet being operatively connected with said member carrying said friction wheel for moving the latter into engagement with said brake block whereby said movable arm of said control switch is displaced and the contacts of the control switch engage each other whereby said electromagnetic means is energized; and a second control magnet in the circuit of said control switch and operatively connected with said member carrying said friction wheel for returning the latter to the position driven by said drive means whereby ink is transferred from said first surface to the second surface while said roller and said copy sheet are at a standstill.

'10. A selective printing machine as set forth in claim 9 and including means for adjusting the distance between said contacts of said control switch.

11. A selective printing machine as set forth in claim 9 wherein each of said selector switches is associated with one of said sections of said text; and including a plurality of manually operated keys respectively connected with said selector switches whereby the latter are closed by selective operation of said selector keys.

12. A selective printing machine as set forth in claim 9 wherein said electromagnetic means includes a winding connected with said control switch, and a core having a narrow elongated end face having a width corresponding to the Width of a section of said text, and a length corresponding to the length of the text section.

13. A selective printing machine as set forth in claim 9 wherein said electromagnetic means includes a first electromagnetic means having a first core located opposite said first surface of said roller so that said copy sheet is located between said first code and said first surface of said roller, and second electromagnetic means located within said roller and including a second core located opposite said first core and having a polarity opposite to the polarity of said first core so that the magnetic field is produced between said first and second cores.

14. A selective printing machine comprising, in combination, a rotary printing roller having a peripheral surface; an elastic magnetizable printing form having a first surface with a text having text sections mounted on said peripheral surface; inking means for inking said first surface of said printing form; a roller having a second surface forming a gap with said first surface; means for rotating said rollers in synchronism so that said surfaces move in synchronism in a given direction; electromagnetic means located in at least one of said rollers and being energizable for producing in said gap a magnetic field narrow in said given direction corresponding to the circumferential extension of a text section on said printing form; means for energizing said electromagnetic means only when selected sections of said printing form pass through said gap, and for deenergizing said electromagnetic means when non-selected text sections pass the same so that the magnetic field deforms a section of said printing form into a buldge in contact with said second surface for transferring the ink of one text section from a section of said first surface of said printing form to a corresponding section of said second surface of said blanket whereby images of only selected sections are transferred.

15. A selective printing machine as set forth in claim 8 and including a rotary magnetic cleaning roll cooperating with one of said surfaces and being spaced from the same by a gap, said rotary magnetic roll being positioned so that the inked text sections on said one surface ar rive at said magnetic cleaning roll after having engaged a copy sheet, said magnetic cleaning roll producing a magnetic force attracting magnetic ink on said one surface so that the latter is cleaned, and means for removing ink from said magnetic cleaning roll.

16. In a selective printing machine, in combination, a printing roller having a peripheral surface for carrying a magnetic printing form permanently magnetized in accordance with a text having text sections; an inking roller having a peripheral surface forming a gap with the surface of the printing form; means for applying a magnetic ink to said peripheral surface of said inking roller; means for rotating said printing roller and said inking roller in synchronism; said inking roller having a plurality of circumferentially adjacent magnetizable sections narrow in circumferential direction corresponding to the circumferential extension of a text section on said printing form, and a winding about each of said magnetizable sections; commutator means connected with said inking roller for rotation and having circumferentially adjacent contacts respectively electrically connected with said windings; slide contact means cooperating with said commutator contacts; and selector means for energizing selected windings when selected text sections of said printing form are located at said gap whereby ink is transferred from said peripheral surface to said surface of Said printing form by the magnetic force exerted by said magnetic printing form when a winding passing said gap is not energized, whereas when an energized winding is located at said gap, the magnetic force of said magnetic printing form is compensated so that no ink is transferred from said inking roller to the respective text section of said printing form.

17. Inking apparatus as set forth in claim 16 and including moistening means for moistening said surface of said printing form.

18. Inking apparatus as set forth in claim 16 wherein said means for energizing said windings include contact means rotating in synchronism with said inking roller; and a plurality of selector switches connected by said contact means with said windings so that only selected windings are energized when located at said gap.

19. A selective printing apparatus comprising, in combination, a first roller having a first surface; means for applying ink to said first surface in the form of atext having sections adjacent in circumferential direction of said first roller; a second roller including a plurality of magnetizable circurnferentially adjacent core sections, and a winding about each of said core sections, said second roller having gripper means for gripping and transporting copy sheets having a second surface so that said first and second surfaces for a gap, said windings and cores, when energized, producing a magnetic field in said gap having a predetermined width in circumferential direction of said first and second roller corresponding to a section of the text inked on said first surface; drive means; first transmission means including a coupling having a coupled position for connecting said drive means with said first roller and a disengaged position; second transmission means including a second coupling having a coupled position for connecting said second roller with said drive means and a disengaged position; brake means for braking said first and second coupling means and thereby said first and second rollers in said disengaged positions; a first spring urging said first coupling means to said coupling position; a second spring urging said second coupling means to said disengaged position; a first control magnet connected with said first coupling means for moving the same to said disengaged position against the action of said first spring; a second control magnet connected to the second coupling means for moving the same to said coupling position; a rotary control contact means driven in synchronism with said first and second rollers; a plurality of selector switches respectively associated with said text sections and electrically connected with said rotary contact means, said selector switches being respectively connected with said windings of said second roller so that selected windings are energized when the respective core section is located at said gap and the respective selector switch is closed; manually operable means for normally blocking said first coupling means in said disengaged position in which said first roller is blocked so that upon manual operation of said blocking means said first coupling means is released to be moved by said first spring to said coupled position whereby said first roller is driven; and circuit means connecting said rotary contact means with said second control magnet and including a control switch which is normally closed so that said second control magnet is energized and moves said second coupling means to said coupled position whereby said second roller rotates in synchronism with said first roller while a selected winding is energized, said second control magnet being deenergized when said rotary contact means connects an open selector switch into the circuit so that second spring moves said second coupling means to said disengaged position whereby said second roller is braked and stopped while an undesired section of the text moves with the rotating first roller through said gap; and a cam rotating with said second roller and cooperating with said control switch for shifting the same to an open position whereby said first control magnet moves said first coupling means to said disengaged position, and said second spring moves said second coupling means to said disengaged position so that said first and second rollers are braked and stopped.

20. A selective printing machine as set forth in claim 19 wherein said first and second coupling means respectively include first and second coupling levers and first and second friction Wheels rotatably mounted on said first and second coupling levers; wherein said drive means include a friction drive wheel; and wherein said first and second friction wheels engage said drive wheel when said first and second coupling means are in said coupled position, and engage said brake members when said first and second coupling means are in said disengaged positions; and wherein said first and second control magnets and said first and second springs are respectively connected with said first and second coupling levers.

21. A selective printing machine as set forth in claim 19 and including a commutator rotating in synchronism with said second roller and having commutator contacts connected With said windings; and including slide contact means engaging said commutator contacts and electrically connected with said selector switches.

22. A selective printing machine as set forth in claim 19 and including a plurality of stationary contacts respectively associated with text sections and respectively connected with said selector switches, said stationary contacts being successively engaged by said rotary contact means; and including a pair of stationary contacts respectively connected to the contacts of said control switch, and being closed by said rotary contact arm after each revolution of said first roller.

23. A selective printing machine comprising, in combination, electromagnetic means for producing, when energized, a magnetic field having in a given direction a predetermined Width corresponding to a section of a text to be printed; first means having a first surface; second means having a second surface forming a gap with said first surface; means for applying a magnetic ink to said first surface so that said ink forms text sections having said predetermined width on corresponding surface sections; drive means; first and second coupling means for connecting the drive means with said first and second means, respectively, and having a coupled position for moving said surfaces in said given direction through said magnetic field, and a disengaged position; brake means controlled by said coupling means in said disengaged position for braking and stopping said first and second means with said first and second surfaces; selector means for energizing said electromagnetic means only when selected sections pass through said magnetic field, and for deenergizing said electromagnetic means when non-selected text sections pass the same so that the same controls the transfer of magnetic ink of each selected test section on a section of said first surface having said predetermined width to a corresponding section of said second surface whereby only text sections selected by energization of the electromagnetic means and having said predetermined width are printed; and means controlled by said selector means and controlling said first and second coupling means so that the same are moved to said disengaged positions and said first and second means are braked and stopped while said electromagnetic means is energized and ink is transferred from said first surface to said second surface.

24. A selective printing machine comprising, in combination, an electromagnetic means for producing, when energized, a magnetic field having in a given direction a predetermined Width corresponding to a section of a text; first means having a first surface; second means having a second surface forming a gap with said first surface; means for applying a magnetic ink to said first surface so that said ink forms text sections having said predetermined width on corresponding surface sections; drive means for driving said first means for moving said first surface in a given direction through said magnetic field; coupling means connecting said drive means with said second means for moving said second surface in synchronism with said first surface through said magnetic field; selector means for energizing said electromagnetic means only with selected text sections pass through said magnetic field, and for deenergizing said electromagnetic means when non-selected text sections pass the same so that the same controls the transfer of magnetic ink of each selected text section on a section of said first surface having said predetermined width to a corresponding section of said second surface whereby only text sections selected by energization of the electromagnetic means and having said predetermined width are transferred; and means controlled by said selector means for moving said coupling means to a disengaged position, and for braking and stopping said second means when non-selected sections of said first surface pass said electromagnetic means in de-energized condition whereby transferred imprints of text sections spaced on said first surface are made adjacent each other on said second surface.

References Cited UNITED STATES PATENTS (Other references on following page) 23 UNITED STATES PATENTS Huebner 101181 Huebner 101-426 Huebner 101--426 Wellcome 101-149.2 Sims 17823 Sims 1786.6

Berry 101401.1

24 Kuleska 117-17.5 Ritzerfeld et a1. 101132.5 Ritzerfeld et a1 101--91 Ritzerfeld et a1 101--142 Berry 101-426 Schwartz 10192 WILLIAM B. PENN, Primary Examiner.

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