JP4376363B2 - Printing device - Google Patents

Description

[0001]
The present invention relates to a printing apparatus that performs printing by pressing a printing pressure member against an outer peripheral surface of a plate cylinder via a sheet, and more particularly to adjustment of pressure of the printing pressure member.
[0002]
[Prior art]
In a printing apparatus typified by a stencil printing apparatus, a printing pressure member such as a press roller is provided on the outer peripheral surface of the plate cylinder so as to be able to come into contact with and separate from the plate cylinder on which the master made by punching is wound on the outer peripheral surface. ing. In such a printing apparatus, ink is supplied to the inner peripheral surface of the plate cylinder by the ink supply means arranged inside the plate cylinder, and the paper is continuously pressed by the printing pressure member against the master on the outer peripheral surface of the plate cylinder. Thus, ink is oozed out from the perforated portion of the plate cylinder and the perforated portion of the master for printing. The printing pressure member is supported by one end of a swingable support member and can be brought into and out of contact with the outer peripheral surface of the plate cylinder, and by the spring force of a tension spring locked to the support member, It is provided so as to be pressed against the outer peripheral surface of the plate cylinder.
[0003]
In the printing apparatus, a plurality of plate cylinders and printing pressure members facing each other are arranged in parallel from the upstream side to the downstream side in the paper conveyance direction, and multicolor printing can be performed by supplying different color inks to each plate cylinder. Things have been proposed.
[0004]
[Problems to be solved by the invention]
In a conventional printing apparatus, a printing pressure member such as a press roller is pressed against the outer peripheral surface of the plate cylinder at once due to the swinging motion of the support member and the spring force of the tension spring. In some cases, a high impact noise is generated or the printing pressure member bounces when it comes into pressure contact with the outer peripheral surface of the plate cylinder. When the printing pressure member bounces, the pressing force on the outer peripheral surface of the paper and the plate cylinder changes, so that a white portion extending in the longitudinal direction of the printing pressure member is generated in the print image and the printing quality is deteriorated or the printing quality is reduced. As the running resistance changes, the paper penetration into the printing section formed between the outer peripheral surface of the plate cylinder and the printing pressure member becomes unstable, and the printing pressure position shifts, and the conveyance force for the paper decreases. There is a problem that it will. In particular, these problems tend to increase when the printing apparatus is printing at high speed and the printing member is in contact and separation speed.
[0005]
Even in a printing apparatus capable of multicolor printing, the rapid contact between the outer peripheral surface of the plate cylinder and the printing pressure member leads to the generation of a high collision noise, and the printing pressure member is in contact with the outer peripheral surface of the plate cylinder. May bounce. In a printing apparatus capable of multicolor printing, when the printing pressure member bounces from the outer peripheral surface of the plate cylinder and the conveyance force decreases, the paper feeding timing of the paper conveyed from the upstream side to the downstream side is particularly shifted, and the upstream side Printing on the upstream side and the downstream side of the image, or the ink transferred to the paper printed on the upstream side adheres to the downstream master and is then transported upstream When the image is re-transferred to the paper that has been finished, the re-transfer position may be shifted, and a so-called ghost image may be generated.
[0006]
The present invention has been made to solve the above-described problems, and provides a printing apparatus that is excellent in quietness, has very few white spots and image position deviation, and can obtain a high-quality printed image. For the purpose.
An object of the present invention is to provide a printing apparatus capable of multi-color printing, which is excellent in quietness, hardly generates ghost images due to white spots or mistransfer of ink, and can obtain a high-quality printed image. .
[0007]
[Means for Solving the Problems]
In order to achieve the above-described object, the invention described in claim 1 includes a plate cylinder, It can be displaced between a printing pressure position that is pressed against the outer peripheral surface of the plate cylinder and a spaced position that is separated from the outer peripheral surface of the plate cylinder. In a printing apparatus that performs printing by pressing a printing pressure member against an outer peripheral surface of a plate cylinder through a sheet, the pressing force of the printing pressure member against the outer peripheral surface of the plate cylinder is provided. adjust Driving means for displacing the printing pressure member from the separated position to the printing pressure position It has composition which has. The pressing force of the printing member against the outer peripheral surface of the plate cylinder is By displacing the printing pressure member from the separated position to the printing pressure position by the drive means As a result of the adjustment, the collision force between the printing pressure member and the plate cylinder is alleviated, the impact sound between the outer peripheral surface of the plate cylinder and the printing pressure member, the bounce of the printing pressure member is reduced, the pressing force against the paper and the running resistance Fluctuations can be suppressed.
[0009]
The invention of claim 1 The displacement of the printing pressure member from the separation position to the printing pressure position is stopped at a proximity position where the printing pressure member is close to the outer peripheral surface of the plate cylinder, and the printing pressure member stopped at this proximity position is moved to the printing pressure position. Control means for controlling the drive of the drive means is arranged so as to be displaced and held at the same printing pressure position. Since the printing member is controlled by the control unit, the printing unit stops at a position close to the outer peripheral surface of the plate cylinder when displaced from the separation position to the printing pressure position. , The impact sound between the outer peripheral surface of the plate cylinder and the printing pressure member and the bounce of the printing pressure member are reduced, and fluctuations in the pressing force and running resistance against the paper can be suppressed.
[0011]
Claim 2 The invention described is A printing cylinder, a printing pressure position in pressure contact with the outer circumferential surface of the printing cylinder, and a printing pressure member that is displaceable to a separated position away from the outer circumferential surface of the printing cylinder, and is disposed opposite to the printing drum, In a printing apparatus that performs printing by pressing the printing pressure member against the outer peripheral surface of the plate cylinder via a sheet, the pressing force of the printing pressure member against the outer peripheral surface of the plate cylinder is adjusted, and the printing pressure position is changed from the separated position. Has a cam for displacing the printing pressure member. A first cam portion that holds the printing pressure member in a proximity position close to the outer peripheral surface of the plate cylinder when the printing pressure member is displaced from the separation position to the printing pressure position; and the printing pressure member from the proximity position to the printing pressure position. A second cam portion that displaces the printing pressure member, and a third cam portion that holds the printing pressure member in the printing pressure position. Have It is configured to do. When the printing pressure member is displaced from the separated position to the printing pressure position, the first cam portion holds the printing pressure member in a close position, so that the collision force between the printing pressure member and the plate cylinder is reduced, and the printing cylinder is in contact with the outer peripheral surface of the printing cylinder. Impact noise with the pressure member and bounce of the printing pressure member are reduced, and fluctuations in the pressing force and running resistance against the paper can be suppressed. The printing pressure member held at the close position is displaced to the printing pressure position by the second cam portion, and is held at the printing pressure position by the third cam portion. It can be suppressed.
[0012]
Claim 3 The described invention is claimed. 2 In the printing apparatus described above, a cam follower provided with a cam follower that contacts the first cam portion, the second cam portion, and the third cam portion at one end and a printing pressure member supported at the other end, and a cam follower The first cam portion is configured to have a guide member that is movably guided along the third cam portion. Since the cam follower provided on the support member is guided by the guide member along the third cam portion from the first cam portion, the contact state between the cam follower and the cam is well maintained and supported by the other end of the support member. The displacement operation of the printing pressure member from the separated position to the printing pressure position is stabilized, and the bounce of the printing pressure member is suppressed, and fluctuations in the pressing force against the paper and the running resistance are reduced.
[0013]
Claim 4 The invention described in claims 1 to 3 In the printing apparatus according to any one of the above, a plurality of plate cylinders and printing pressure members are arranged in parallel from the upstream side to the downstream side in the paper transport direction. Printing is performed on the sheet moving from the upstream side to the downstream side by each plate cylinder and each printing pressure member. The pressing force of each printing pressure member on the outer peripheral surface of each plate cylinder is a driving means, a cam, etc. Therefore, the impact force between each printing member and each plate cylinder is alleviated, and the impact sound between the outer peripheral surface of each plate cylinder and each printing member and the bounce of the printing member are generated. And the fluctuation of the pressing force against the paper and the running resistance can be suppressed. In addition, since fluctuations in the pressing force and running resistance against the paper can be suppressed, deviations in paper feed timing from the upstream side to the downstream side can be reduced.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, several embodiments according to the present invention will be described with reference to the drawings. In the respective embodiments, components having the same function and shape are denoted by the same reference numerals, and description thereof is omitted as much as possible. In the figure, components that are configured as a pair and do not need to be specifically distinguished and described are distinguished by adding A and B after the same numerical symbol, and one of them is appropriately selected for the sake of simplification of description. The description shall be replaced with the description.
(First embodiment)
FIG. 1 shows a main part of a stencil printing apparatus which is an embodiment of a printing apparatus. In FIG. 1, reference numeral 1 denotes a plate cylinder, and a press roller 2 is disposed opposite to the plate cylinder 1 as a printing pressure member. The press roller 2 is pressed against the sheet 3 between the outer peripheral surface of the plate cylinder 1 (hereinafter referred to as “plate cylinder outer peripheral surface 1a”) and the outer peripheral surface 2a of the press roller 2 (hereinafter referred to as “roller outer peripheral surface 2a”). The printing unit 4 is configured to perform printing. A transport path 32 formed by a pair of upper and lower guide plates 30 and 31 that guides the paper 3 fed from a paper feeding unit (not shown) to the printing unit 4 upstream of the printing unit 4 in the paper transport direction X. Has been placed. On the downstream side of the printing unit 4 in the paper transport direction X, a separation claw 33 for separating the paper 3 adhering to the plate cylinder outer peripheral surface 1a due to the viscosity of the ink is close to the plate cylinder outer peripheral surface 1a indicated by a virtual line. And a stand-by position separated from the plate cylinder outer peripheral surface 1a indicated by a solid line so as to be swingable. The position of the separation claw 33 is controlled by a drive mechanism (not shown) so that it occupies a standby position when the clamper 15 passes the vicinity thereof, and occupies a separation position when the clamper 15 passes the vicinity thereof.
[0015]
The paper feed unit in this embodiment is a paper feed tray for stacking and storing unprinted paper, a paper refeed tray for storing single-sided printed paper when performing double-sided printing, and paper having a similar function Refers to the storage section.
[0016]
As shown in FIG. 1, the plate cylinder 1 is rotatably supported around a hollow support shaft 19, and is rotated in the clockwise direction during printing in FIG. 1 by a drive motor 25 as a plate cylinder driving means. . The plate cylinder 1 is configured by superposing a porous support cylinder 13 and a mesh screen (not shown). The support cylindrical body 13 is formed with an opening region portion 16 through which ink can pass and a non-opening region portion 17 that blocks the passage of ink. The plate cylinder 1 is a clamper 15 serving as a master locking means provided on the plate cylinder outer peripheral surface 1a side of the non-opening region portion 17 and locks the leading end of the master 14 (hereinafter referred to as “master 14”). And it is wound around the plate cylinder outer peripheral surface 1a. The clamper 15 is provided along the generatrix of the outer peripheral surface of the support cylindrical body 13, and opens and closes when the plate is wound around the master 14 and when the rolled master 14 is discarded. It is configured as follows.
[0017]
Inside the plate cylinder 1, ink supply means 20 for supplying ink to the inner peripheral surface of the plate cylinder 1 is disposed. The ink supply means 20 is arranged in parallel with an ink roller 21 for supplying ink to the inner peripheral surface of the plate cylinder 1 and a small gap with the ink roller 21, and a wedge-shaped ink reservoir 23 between the ink roller 21 and the ink roller 21. And a support shaft 19 provided with an ink supply port 18 for supplying ink to the ink reservoir 23 and functioning also as an ink pipe. The ink roller 21 and the doctor roller 22 are rotatably supported by side plates (not shown) fixed to the support shaft 19. The ink roller 21 is rotated in the same direction in synchronization with the rotation of the plate cylinder 1 by a driving force transmission means such as a gear or a belt. The ink is pumped by an ink pump from an ink pack (not shown) arranged at an appropriate position, and is supplied to the ink reservoir 23 from the ink supply port 18 of the support shaft 19.
[0018]
As shown in FIGS. 1 and 2, the press roller 2 is located between a separation position away from the plate cylinder outer circumferential surface 1a and a printing pressure position where the roller outer circumferential surface 2a is in pressure contact with the plate cylinder outer circumferential surface 1a shown in FIG. It is provided to be displaceable.
[0019]
The stencil printing apparatus in this embodiment uses a cam 5 as pressure adjusting means for adjusting the pressing force of the press roller 2 against the plate cylinder outer peripheral surface 1a. An arm member 8 as a support member is disposed between the plate cylinder 1 and the cam 5 so as to be swingable about a support shaft 7 that is rotatably supported by an apparatus main body (not shown). At one end 8a of the arm member 8, a roller 9 as a cam follower that contacts the outer peripheral contour surface of the cam 5 is rotatably supported. The press roller 2 is rotatably supported by the shaft 10 at the other end 8 b of the arm member 8. A torsion coil spring 12 having one end locked to a fixed spring hook portion 11 and the other end locked to the other end 8b side of the arm member 8 is wound around the support shaft 7, as shown in FIG. Is provided with a habit of turning counterclockwise about the support shaft 7. The counterclockwise direction is a separation direction in which the press roller 2 is moved away from the plate cylinder outer peripheral surface 1 a and is also a direction in which the roller 9 is pressed against the cam 5. That is, the press roller 2 is biased in a direction away from the plate cylinder outer peripheral surface 1a.
[0020]
The cam 5 displaces the press roller 2 stepwise between the separation position and the printing pressure position, and is fixed to a drive shaft 6 that is rotated counterclockwise in FIG. 1 by a driving force transmission means (not shown). And is rotated at the same peripheral speed as the peripheral speed of the plate cylinder 1. As shown in FIG. 3, when the press roller 2 is displaced from the separation position to the printing pressure position, the cam 5 temporarily places the press roller 2 at a close position where the roller outer peripheral surface 2a contacts the plate cylinder outer peripheral surface 1a. The first cam portion 5a to be held, the second cam portion 5b for displacing the press roller 2 from the proximity position shown in FIG. 3 to the printing pressure position shown in FIG. 4, and the press roller 2 in a predetermined range are shown in FIG. The third cam portion 5c that holds the printing roller at the printing pressure position, the fourth cam portion 5d that holds the press roller 2 at the separation position shown in FIG. 1, and the separation of the pressing roller 2 shown in FIG. 1 from the printing pressure position shown in FIG. The fifth cam portion 5e that guides to the position and the sixth cam portion 5f that guides the press roller 2 placed at the separated position to the close position shown in FIG. It has a concave shape. The predetermined range in which the press roller 2 is held at the printing pressure position is a range in which at least the printing area of the sheet 3 is in pressure contact with the plate cylinder outer peripheral surface 1 a via the master 14.
[0021]
When each cam surface is based on the fourth cam portion 5d, the sixth cam portion 5f, the first cam portion 5a, the second cam portion 5b, the third cam portion 5c, and the fifth cam portion 5e are rotated clockwise. It is formed continuously in order. The first cam portion 5a, the third cam portion 5c, and the fourth cam portion 5d are each formed on an arc surface centered on the drive shaft 6, and when the roller 9 is in contact with each portion, the press roller 2 Are held at positions corresponding to the respective cam portions. The first cam portion 5a holds the press roller 2 in the close position, the third cam portion 5c holds the press roller 2 in the printing pressure position, and the fourth cam portion 5d holds the press roller 2 in the separated position. That is, the first cam portion 5d is placed at a position closest to the drive shaft 6, the third cam portion 5c is placed at a position farthest from the drive shaft 6, and the first cam portion 5a is connected to the fourth cam portion 5d and the fourth cam portion 5d. It is placed in the middle of the three cam portions 5c. In the present embodiment, the clamper 15 is configured to pass through the printing unit 4 when the roller 9 is located in the range from the fifth cam portion 5e to the sixth cam portion 5f.
[0022]
The pressing force applied to the outer peripheral surface 1a of the plate cylinder by the press roller 2 occupying the close position is such that ink does not ooze out from the inside of the plate cylinder 1, and an extremely weak pressing force that does not generate a collision sound with the outer peripheral surface 1a of the plate cylinder. It is. The pressing force applied to the plate cylinder outer peripheral surface 1a by the press roller 2 occupying the printing pressure position is a complete printing pressure that allows ink to ooze out from the inside of the plate cylinder 1 to obtain a high-quality printed image. In this embodiment, the proximity position is a state in which the plate cylinder outer peripheral surface 1a and the roller outer peripheral surface 2a are in contact with each other via the master 14, but the two are slightly separated from each other. 1a and the roller outer peripheral surface 2a may not be in contact with each other, or the plate cylinder outer peripheral surface 1a and the roller outer peripheral surface 2a may be in contact with each other without the master 14. The point is that the gap setting and the pressing force should be such that no collision noise or bounce of the press roller 2 occurs when the plate cylinder outer peripheral surface 1a and the roller outer peripheral surface 2a come into contact or pressure contact.
[0023]
The stencil printing apparatus according to the present embodiment includes a well-known plate making / plate feeding device (not shown) for making a plate-making master by making a plate-making signal with a plate-making signal and feeding the plate to the plate cylinder 1, and a used master as a plate-cylinder outer peripheral surface. It is equipped with a well-known unillustrated plate discharging device that is peeled off from 1a and can be mechanically performed from the plate making to the plate discharging, but the plate making / plate feeding device and the plate discharging device are individually provided. Of course, a stencil printing apparatus of the type that manually performs plate feeding and discharging is acceptable.
[0024]
The operation of the stencil printing apparatus configured as described above will be described.
In the present embodiment, as shown in FIG. 1, it is assumed that the master 14 is wound on the outer peripheral surface 1a of the plate cylinder and the so-called plate printing operation is completed. FIG. 5 shows a printing pressure timing chart of the press roller 2.
[0025]
After setting the number of prints with a numeric keypad provided on an operation panel (not shown), when a start key (not shown) is pressed, the drive motor 25 is driven to rotate the plate cylinder 1 in the clockwise direction and the cam. 5 rotates counterclockwise. In synchronization with the rotation of the plate cylinder 1, the paper 3 is fed in the paper transport direction X from a paper feed unit (not shown).
[0026]
Since the press roller 2 is urged in the separation direction (downward in FIG. 1) by the spring force of the torsion coil spring 12, as shown in FIG. 2, the roller 9 is positioned on the fourth cam portion 5d. It is held at the separated position (section A in FIG. 5). When the rotation of the cam 5 advances and the sixth cam portion 5f is positioned at the portion facing the roller 9, the roller 9 is pushed up by the sixth cam portion 5f as shown in FIG. As a result, the arm member 8 rotates in the clockwise direction around the support shaft 7 against the spring force of the torsion coil spring 12, and moves the press roller 2 toward the plate cylinder outer peripheral surface 1a (section 5 in FIG. 5). B).
[0027]
When the cam 5 rotates and the roller 9 reaches the first cam portion 5a, the press roller 2 is placed in a proximity position where the roller outer peripheral surface 2a contacts the plate cylinder outer peripheral surface 1a. This proximity position is maintained while the roller 9 is positioned on the first cam portion 5a even if the cam 5 rotates (section C in FIG. 5). At this time, the leading edge 3a of the sheet 3 does not reach the printing unit 4, but the unopened region 17 is located in the printing unit 4 and the pressing force by the press roller 2 does not cause ink to ooze out. Therefore, even if the press roller 2 is in contact with the outer peripheral surface 1a of the plate cylinder, the ink does not bleed out, and the ink stain on the press roller 2 is prevented.
[0028]
When the rotation of the cam 5 further proceeds, the roller 9 reaches the second cam portion 5b, and the roller 9 is further pushed up by the second cam portion 5b as shown in FIG. As a result, the arm member 8 further rotates clockwise around the support shaft 7 against the spring force of the torsion coil spring 12 to displace the press roller 2 from the proximity position to the printing pressure position (FIG. 5). Section D). At this time, the sheet 3 is conveyed to the printing unit 4, and the opening cylinder 16 is positioned in the printing unit 4 with the rotation of the plate cylinder 1, so that the roller outer peripheral surface 2a is moved by the upward displacement of the press roller 2. When the roller 9 is pressed against the outer peripheral surface 1a of the plate cylinder via the paper 3 and the roller 9 is positioned on the third cam portion 5c, a complete printing pressure state is obtained. This complete printing state is maintained only while the roller 9 is in pressure contact with the third cam portion 5c (section E in FIG. 5).
[0029]
The sheet 3 fed to the printing unit 4 is held and held by the plate cylinder outer peripheral surface 1a and the roller outer peripheral surface 2a, and is continuously pressed by the master 14 wound around the plate cylinder outer peripheral surface 1a. Printing is performed by transferring ink from the perforated portion of the master 14 to the surface of the paper 3.
[0030]
In this way, the pressing force of the press roller 2 against the outer peripheral surface 1a of the plate cylinder is adjusted by displacing the position of the press roller 2 stepwise from the separation position to the printing pressure position with the cam 5. The collision force at the time of contact between the surface 1a and the press roller 2 is alleviated, impact noise and bounce of the press roller 2 are reduced, and fluctuations in running resistance with respect to the paper 3 are suppressed. For this reason, the quietness of the apparatus is improved, and white spots and image position deviation caused by the bounce are extremely reduced, and a high-quality printed image can be obtained. Further, since the press roller 2 is pushed up by the cam 5 and displaced from the separation position to the printing pressure position, the displacement operation can be performed more reliably than in the conventional case where the pressing force is performed by a spring force.
[0031]
When the rotation of the cam 5 advances and the roller 9 reaches the fifth cam portion 5e from the third cam portion 5c, the pressing action by the third cam portion 5c is reduced. As a result, the arm member 8 is rotated counterclockwise around the support shaft 7 by the spring force of the torsion coil spring 12, and the press roller 2 moves from the printing pressure position shown in FIG. 4 to the separation position shown in FIG. (Section F in FIG. 5).
[0032]
Such contact / separation operation of the press roller 2 is sequentially executed until the set number of prints is completed, and when the printing corresponding to the number of prints is completed, the drive motor 25 and the paper feeding operation are stopped and the press roller 2 is The printing operation is ended by being held in the separated position and entering a standby state.
(Second Embodiment)
As shown in FIG. 6, this embodiment is provided with a guide member 35 that guides a roller 9 as a cam follower so as to be movable from the first cam portion 5a along the third cam portion 5c. Is different. The other configuration is the same as that of the first embodiment.
[0033]
The guide member 35 is formed in a U-shaped cross section so that the roller 9 is sandwiched from above and below with respect to the movement, and the roller 9 is movable in the inside. The guide member 35 has a shape similar to the cam shape from the sixth cam portion 5f to the third cam portion 5c located downstream of the first cam portion 5a in the rotation direction of the cam 5, and is attached to the cam 5. ing.
[0034]
When the guide member 35 having such a configuration is provided, the roller 9 is forcibly moved along the cam 5 by the guide member 35 in the range from the sixth cam portion 5f to the third cam portion 5c. Thus, the roller 9 is prevented from being lifted. For this reason, the contact state between the roller 9 and the cam 5 is well maintained, the displacement operation of the press roller 2 from the separated position to the printing pressure position is stabilized, the quietness of the apparatus is improved, and it occurs due to bounce. It is possible to surely reduce white spots and image position shifts, and to obtain a high-quality printed image.
(Third embodiment)
In this embodiment, as shown in FIG. 7, one end 8 a side of the arm member 8 that supports the roller 9 is pulled by the tension spring 70, and the press roller 2 is pressed against the outer peripheral surface 1 a of the plate cylinder using the spring force of the tension spring 70. To do. For this reason, although the cam 50 different from the cam 5 in the first embodiment is used as the pressure adjusting means, other basic configurations are substantially the same as those in the first embodiment.
[0035]
The cam 50 forms a convex cam with respect to the concave cam 5 and is fixed to the drive shaft 6. In this embodiment, the cam 50 rotates in the clockwise direction in synchronization with the rotation of the plate cylinder 1. It is configured to rotate at the same peripheral speed as the speed.
[0036]
As shown in FIG. 7, when the press roller 2 is displaced from the separation position to the printing pressure position, the cam 50 temporarily moves the press roller 2 to a close position where the roller outer peripheral surface 2a contacts the plate cylinder outer peripheral surface 1a. The first cam portion 50a to be held, the second cam portion 50b for displacing the press roller 2 from the proximity position to the printing pressure position shown in FIG. 4, and the press roller 2 at a printing pressure position shown in FIG. The third cam portion 50c to be held, the fourth cam portion 50d to hold the press roller 2 in the separated position shown in FIG. 1, and the press roller 2 are guided from the printing pressure position shown in FIG. 4 to the separated position shown in FIG. The fifth cam portion 50e and the sixth cam portion 50f for guiding the press roller 2 placed in the separated position to the close position shown in FIG. 7 have a specific shape formed on the outer peripheral contour surface thereof. Yes. Here, the predetermined range is a range in which at least the printing area of the sheet 3 is in pressure contact with the plate cylinder outer peripheral surface 1 a via the master 14.
[0037]
When each cam surface is based on the fourth cam portion 50d, the sixth cam portion 50f, the first cam portion 50a, the second cam portion 50b, the third cam portion 50c, and the fifth cam portion 50e are counterclockwise. Are formed continuously in this order. The first cam portion 50a, the third cam portion 50c, and the fourth cam portion 50d are each formed on an arc surface centered on the drive shaft 6, and when the roller 9 is in contact with each portion, the press roller 2 Are held at positions corresponding to the respective cam portions. The first cam portion 50a holds the press roller 2 in the close position, the third cam portion 50c holds the press roller 2 in the printing pressure position, and the fourth cam portion 50d holds the press roller 2 in the separated position. That is, the fourth cam portion 50d is placed at the position farthest from the drive shaft 6, the third cam portion 50c is placed at the position closest to the drive shaft 6, and the first cam portion 50a is connected to the fourth cam portion 50d and the fourth cam portion 50d. It is placed in the middle of the three cam portions 50c. In the present embodiment, the clamper 15 is configured to pass through the printing unit 4 when the roller 9 is located in the range from the fifth cam portion 50e to the sixth cam portion 50f.
[0038]
Also in this embodiment, the pressing force applied to the plate cylinder outer peripheral surface 1a by the press roller 2 occupying the close position is such that the ink does not ooze out from the inside of the plate cylinder 1, and a collision sound is generated when contacting the plate cylinder outer peripheral surface 1a. It is said that it is extremely weak that does not occur. The pressing force applied to the plate cylinder outer peripheral surface 1a by the press roller 2 occupying the printing pressure position, that is, the urging force of the tension spring 70 allows the ink to ooze out from the inside of the plate cylinder 1 to obtain a high-quality printed image. It is printing pressure.
[0039]
According to the stencil printing apparatus provided with such a cam 50, the press roller 2 is urged in the printing pressure direction (upward in FIG. 7) by the spring force of the tension spring 70. While 9 is positioned, it is held at the separated position as shown in FIG. 2 (section A in FIG. 5). When the rotation of the cam 50 progresses and the sixth cam portion 50f is positioned at the portion facing the roller 9, the arm member 8 is moved around the support shaft 7 by the spring force of the tension spring 70 as shown in FIG. It rotates in the turning direction, and the press roller 2 is displaced toward the plate cylinder outer peripheral surface 1a (section B in FIG. 5).
[0040]
When the cam 50 rotates and the roller 9 reaches the first cam portion 50a, the press roller 2 is placed in the proximity position shown in FIG. 7 where the roller outer peripheral surface 2a contacts the plate cylinder outer peripheral surface 1a. This proximity position is maintained while the roller 9 is positioned on the first cam portion 50a even if the cam 50 rotates (section C in FIG. 5). At this time, the leading edge 3a of the sheet 3 does not reach the printing unit 4, but the unopened region 17 is located in the printing unit 4 and the pressing force by the press roller 2 does not cause ink to ooze out. Therefore, even if the press roller 2 comes into contact with the outer peripheral surface 1a of the plate cylinder, the ink does not bleed out, and the ink stain on the press roller 2 is prevented.
[0041]
When the rotation of the cam 50 further proceeds, the roller 9 reaches the second cam portion 50b, and the arm member 8 further rotates clockwise around the support shaft 7 by the spring force of the tension spring 70, and the press roller 2 Is displaced from the proximity position to the printing pressure position (section D in FIG. 5). At this time, the sheet 3 is conveyed to the printing unit 4, and the opening cylinder 16 is positioned in the printing unit 4 with the rotation of the plate cylinder 1, so that the roller outer peripheral surface 2a is moved by the upward displacement of the press roller 2. When the roller 9 is pressed against the outer peripheral surface 1a of the plate cylinder via the sheet 3 and the roller 9 is positioned on the third cam portion 50c, a complete printing pressure state is obtained. This complete printing state is maintained only while the roller 9 is in contact with the third cam portion 50c (section E in FIG. 5).
[0042]
The sheet 3 fed to the printing unit 4 is held and held by the plate cylinder outer peripheral surface 1a and the roller outer peripheral surface 2a, and is continuously pressed by the master 14 wound around the plate cylinder outer peripheral surface 1a. Printing is performed by transferring ink from the perforated portion of the master 14 to the surface of the paper 3.
[0043]
As described above, the pressing force of the press roller 2 against the outer peripheral surface 1a of the plate cylinder is adjusted by displacing the position of the press roller 2 stepwise from the separation position to the printing pressure position by the cam 50. The collision force at the time of contact between the surface 1a and the press roller 2 is alleviated, impact noise and bounce of the press roller 2 are reduced, and fluctuations in running resistance with respect to the paper 3 are suppressed. For this reason, the quietness of the apparatus is improved, and white spots and image position deviation caused by the bounce are extremely reduced, and a high-quality printed image can be obtained.
[0044]
When the rotation of the cam 50 advances and the roller 9 reaches the fifth cam portion 50e from the third cam portion 50c, the roller 9 is pushed by the fifth cam portion 50e. For this reason, the arm member 8 is rotated counterclockwise around the support shaft 7 against the spring force, the pressing action is reduced, and the press roller 2 moves from the printing pressure position to the separation position ( FIG. 5, section F).
(Fourth embodiment)
In this embodiment, as shown in FIG. 8, two plate cylinders 1A and 1B and two press rollers 2A and 2B as printing pressure members are arranged in parallel from the upstream side to the downstream side in the paper transport direction X. In the stencil printing apparatus capable of multicolor printing, the pressing force of the press rollers 2A and 2B is controlled.
[0045]
The plate cylinder 1A and the press roller 2A are arranged immediately after the conveyance path 32, and the plate cylinder 1B and the press roller 2B are arranged further downstream via the intermediate conveyance device 40, that is, downstream in the paper conveyance direction X. Yes. The configurations of the plate cylinders 1A and 1B and the press rollers 2A and 2B are substantially the same as the above-described embodiments. The difference from each embodiment is that the master 14A wound on the outer peripheral surface 1Aa of the plate cylinder is subjected to plate making corresponding to the color of the first color, and the second color is applied to the master 14B wound on the outer surface 1Ba of the plate cylinder. The plate making according to is performed. The first color ink is supplied to the ink reservoir 23A formed inside the plate cylinder 1A, and the second color ink is supplied to the ink reservoir 23B formed inside the plate cylinder 1B. The first color ink is black and the second color ink is red. The colors of the first and second inks may be different from each other, and which color is supplied to which plate cylinder may be appropriately selected.
[0046]
The plate cylinder 1A and the plate cylinder 1B are configured to be rotated by the drive motor 25 in the clockwise direction at the same peripheral speed. The phases of the plate cylinder 1A and the plate cylinder 1B are shifted so that the leading edge of the image printed through the printing unit 4A and the leading edge of the image printed by the printing unit 4B coincide. When the plate cylinder 1A and the plate cylinder 1B are not rotated by the same drive motor 25 but are rotated by individual drive motors, the phases of the plate cylinder 1A and the plate cylinder 1B may be the same.
[0047]
The intermediate conveying device 40 is an endless conveying belt 43 wound around a driving roller 41 and a driven roller 42, and a conveying surface 43 </ b> A of the conveying belt 43 disposed below the conveying belt 43. A fan 44 that applies a suction force to the motor, a fan drive motor 45 as a driving means thereof, and a transport drive motor 47 that rotates the drive roller 41 are provided. The drive roller 41 is rotated by the conveyance drive motor 47 so that the conveyance belt 43 rotates counterclockwise in FIG. The intermediate conveying device 40 is disposed between a printing unit 4A formed between the plate cylinder 1A and the press roller 2A and a printing unit 4B formed between the plate cylinder 1B and the press roller 2B. The sheet 3 that has passed through the section 4A is conveyed to the printing section 4B. A guide plate 46 is disposed between the drive roller 41 and the printing unit 4B, that is, upstream of the printing unit 4B in the paper transport direction X, and downstream of the printing unit 4B in the paper transport direction X. A separation claw 33B for separating the paper 3 attached to the outer peripheral surface 1Ba due to the viscosity of the ink is disposed. The operations of the separation claws 33A and 33B are the same as those of the separation claws 33.
[0048]
The stencil printing apparatus according to the present embodiment has pressure driving motors 63A and 63B serving as driving means and pressure driving motors 63A and 63B as pressure adjusting means for adjusting the pressing force of the press rollers 2A and 2B against the outer peripheral surfaces 1Aa and 1Ba of the plate cylinder. And a control means 60 for controlling the driving. Stepping motors are used as the pressing drive motors 63A and 63B.
[0049]
The press rollers 2A and 2B are rotatably supported at one ends of arm members 80A and 80B as support members that are swingably supported by the support shafts 7A and 7B, respectively. The support shafts 7A and 7B are rotatably supported by an apparatus main body (not shown). As shown in FIG. 8, the press rollers 2A and 2B are separated from the plate cylinder outer peripheral surfaces 1Aa and 1Ba, and the roller outer peripheral surfaces 2Aa and 2Ba are pressed against the plate cylinder outer peripheral surfaces 1Aa and 1Ba as shown in FIG. It is provided so that it can be displaced between the printing pressure positions. 9 and 10 show only the upstream plate cylinder 1Aa and the press roller 2Aa side.
[0050]
As shown in FIG. 8, gears 62A and 62B are mounted and fixed to the support shafts 7A and 7B, respectively. Drive gears 61A and 61B rotated by press drive motors 63A and 63B mesh with the gears 62A and 62B, respectively.
[0051]
The main part of the control means 60 is composed of a well-known microcomputer equipped with a CPU and a memory, and controls the drive timing, rotation direction, and drive time of the press drive motors 63A, 63B to control the press rollers 2A, 2B. The position is controlled. The control means 60 is a pressing drive motor so that the press rollers 2A and 2B occupy the separated positions when the clampers 15A and 15B pass the printing units 4A and 4B, when printing and printing are finished, or when the apparatus is stopped. The drive timing, rotation direction, and drive time of 63A and 63B are controlled. Immediately after the clampers 15A and 15B have passed the printing sections 4A and 4B during printing and printing, the control means 60 causes the press rollers 2A and 2B to transfer the roller outer peripheral surfaces 2Aa and 2Ba to the plate cylinder outer peripheral surface 1Aa, The drive timing, rotation direction, and drive time of the press drive motors 63A and 63B are controlled so that the press drive motors 63A and 63B are stopped at a close position that contacts the 1Ba via the paper 3. The press rollers 2A and 2B stopped at the close position The drive timing, rotation direction, and drive time of the press drive motors 63A and 63B are controlled so as to move to the position and hold the printing pressure position for a predetermined time. That is, the control means 60 controls the driving of the press drive motors 63A and 63B so that the press rollers 2A and 2B are displaced stepwise from the separated position to the printing pressure position.
[0052]
The predetermined time during which the press rollers 2A and 2B are held at the printing pressure position is a time during which at least the printing area of the sheet 3 is pressed against the plate cylinder outer peripheral surfaces 1Aa and 1Ba via the masters 14A and 14B. In this embodiment, the phases of the plate cylinders 1A and 1B are detected by angle detection means such as a rotation angle detection sensor (not shown), and the control means 60 determines the positions of the clampers 15A and 15B based on the detection information.
[0053]
When the paper 3 has passed through the printing sections 4A and 4B, that is, every time printing on one paper 3 is finished, the control means 60 shows the press rollers 2A and 2B occupying the printing pressure positions in FIG. The driving of the pressing drive motors 63A and 63B is controlled so as to be displaced to the illustrated separation position.
[0054]
According to the stencil printing apparatus configured as described above, the press drive motor 63A is driven and the drive gear 61A rotates counterclockwise in FIG. 8 immediately after the clamper 15A passes the printing unit 4A during printing. The arm member 80A pivots upward about the support shaft 7A, and the press roller 2A occupies the close position and stops. Then, when the pressing drive motor 63A is driven again and the drive gear 61A rotates counterclockwise in FIG. 9, the arm member 80A further pivots about the support shaft 7A, and the press roller 2A moves to FIG. It moves from the proximity position shown to the printing pressure position shown in FIG. The sheet 3 fed from a sheet feeding unit (not shown) to the printing unit 4A is sandwiched and held by the plate cylinder outer peripheral surface 1Aa and the roller outer peripheral surface 2Aa, and continuously on the master 14A wound around the plate cylinder outer peripheral surface 1Aa. By being pressed, ink is transferred from the perforated portion of the master 14A to the surface of the paper 3, and printing of the first color is performed.
[0055]
The sheet 3 that has passed through the printing unit 4A is adsorbed to the conveyance surface 43A by the action of the conveyance belt 43 and the adsorption fan 44 that are driven by the fan drive motor 45 and the conveyance drive motor 47 shown in FIG. It is conveyed toward the printing unit 4B. After the contact / separation operation of the press roller 2B is temporarily stopped at the proximity position by controlling the drive of the pressing drive motor 63B by the control means 60 in the same manner as the operation of the press roller 2A shown in FIGS. Then, it is displaced to the printing pressure position and held for a predetermined time. For this reason, the paper 3 that has reached the printing unit 4B is held and held by the plate cylinder outer peripheral surface 1Ba and the roller outer peripheral surface 2Ba, and is continuously pressed by the master 14B wound around the plate cylinder outer peripheral surface 1Ba. Then, the ink is transferred from the perforated portion of the master 14B to the surface of the paper 3, and the second color printing is performed.
[0056]
When printing in each of the printing units 4A and 4B is completed, the press rollers 2A and 2B occupying the printing pressure positions are displaced to the separation positions shown in FIG. 8, and when the separation positions are occupied, the drive of the press drive motors 63A and 63B is driven. Stop.
[0057]
Such pressing / separating operation of the press rollers 2A and 2B is executed until the set number of prints is finished, and when the printing corresponding to the number of prints is finished, the drive motor 25, the fan drive motor 45, and the transport drive motor 47 are stopped. Then, the printing operation ends.
[0058]
In this way, the pressing force of the press rollers 2A and 2B against the plate cylinder outer peripheral surfaces 1Aa and 1Ba is adjusted by gradually displacing the press rollers 2A and 2B from the separation position to the printing pressure position. The collision force at the time of contact between the outer peripheral surfaces 1Aa, 1Ba and the press rollers 2A, 2B is alleviated, impact noise and bounce of the press rollers 2A, 2B are reduced, and fluctuations in running resistance with respect to the paper 3 are suppressed. For this reason, the quietness of the apparatus is improved, and white spots and image position deviation caused by the bounce are extremely reduced, and a high-quality printed image can be obtained. Further, when the bounce of the press roller 2A is reduced, the deviation of the feeding timing from the upstream printing unit 4A to the downstream printing unit 4B is reduced, and the deviation of the image position between the first color and the second color is reduced. Can be reduced. For this reason, the ink of the paper 3 that adheres to the master 14B wound around the outer peripheral surface 1B of the plate cylinder by the first printing is retransferred to the paper 3 when the next paper 3 is printed. Deviation from the print image printed by the section 4A is reduced, so-called ghost image generation is suppressed, and an image with high print quality can be obtained.
[0059]
In the fourth embodiment, the press rollers 2A and 2B are oscillated and displaced using the pressure drive motors 63A and 63B as pressure adjusting means. However, the cam 5 and the cam 5 described in the first to third embodiments The cam 50 may be used as pressure adjusting means, and the guide member 35 may be disposed together with the cam 5.
[0060]
In the first to third embodiments, the cams 5 and 50 are used as the pressure adjusting means. However, the press roller 2 is moved by the arm member 80 using the pressing drive motors 63A and 63B in the fourth embodiment. You may make it support rotatably.
[0063]
【The invention's effect】
Claim 1 According to the described invention, the driving means for performing the displacement operation of the printing pressure member to the separation position and the printing pressure position is controlled by the control means, and contacts the outer peripheral surface of the plate cylinder when displaced from the separation position to the printing pressure position. Since the collision force between the printing pressure member and the plate cylinder is alleviated by stopping the printing pressure member at the close position where the pressure is applied, the impact sound between the outer peripheral surface of the plate cylinder and the printing pressure member and the bounce of the printing pressure member are reduced. In addition, fluctuations in the running resistance with respect to the paper are suppressed, the quietness of the apparatus is improved, and white spots and image position deviation caused by bounce are extremely reduced, and a high-quality printed image can be obtained.
[0065]
Claim 2 According to the described invention, when the printing pressure member is displaced from the separated position to the printing pressure position, Cam Since the collision force between the printing pressure member and the plate cylinder is eased by being held at the close position by the first cam portion, impact noise between the printing cylinder outer peripheral surface and the printing pressure member and bounce of the printing pressure member are reduced. In addition, fluctuations in the running resistance with respect to the paper are suppressed, the quietness of the apparatus is improved, and white spots and image position deviation caused by the bounce are extremely reduced, and a high-quality printed image can be obtained. Further, the printing pressure member held in the proximity position is guided to the printing pressure position by the second cam portion, and is held in the printing pressure position by the third cam portion for a predetermined range. Since pressure is applied to the outer peripheral surface of the plate cylinder, better printing is performed on the paper, and a high-quality printed image can be obtained.
[0066]
Claim 3 According to the described invention, since the cam follower provided on the support member is guided by the guide member so as to be movable along the third cam portion from the first cam portion, the contact state between the cam follower and the cam is excellent. The displacement operation of the printing pressure member held and supported by the other end of the support member from the separated position to the printing pressure position is stabilized, and the whiteness and image position deviation are extremely reduced while improving the quietness of the apparatus. Thus, a higher quality print image can be obtained.
[0067]
Claim 4 According to the described invention, when printing is performed by the plate cylinders and the printing pressure members on the paper moving from the upstream side to the downstream side, the pressing force of the printing pressure members on the outer peripheral surfaces of the plate cylinders. However, since the collision force between each printing pressure member and each plate cylinder is alleviated by being adjusted by the pressure adjusting means such as the driving means and the cam, respectively, each plate cylinder outer peripheral surface and each printing pressure member Impact noise and the bounce of the printing pressure member are reduced, and fluctuations in running resistance with respect to the paper can be suppressed. For this reason, while improving the quietness of the apparatus, white spots and image position deviations are extremely reduced, and deviations in the feeding timing from the upstream side to the downstream side are reduced, so that the ghost image of the ghost image due to the retransfer deviation is reduced. The generation is extremely reduced, and a high-quality printed image can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a main part of a printing apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a state of a cam, a plate cylinder, and a sheet as pressure adjusting means when a printing pressure member occupies a separated position.
FIG. 3 is a diagram illustrating a state of a cam, a plate cylinder, and a sheet when a printing pressure member occupies a close position.
FIG. 4 is a diagram illustrating a state of a cam, a plate cylinder, and a sheet when a printing pressure member occupies a printing pressure position.
FIG. 5 is a chart of printing pressure timing accompanying the contact and separation operation of the printing pressure member.
FIG. 6 is a diagram illustrating a configuration of a main part of a printing apparatus provided with a guide member according to a second embodiment of the present invention.
FIG. 7 is a diagram illustrating a configuration of a main part of a printing apparatus having a different cam shape according to a third embodiment of the present invention.
FIG. 8 is a diagram illustrating a configuration of a main part of a printing apparatus capable of multicolor printing according to a fourth embodiment of the present invention.
FIG. 9 is a diagram illustrating a state in the vicinity of a printing unit when a printing pressure member occupies a proximity position according to a fourth embodiment.
FIG. 10 is a diagram illustrating a state in the vicinity of a printing unit when a printing pressure member occupies a printing pressure position in the fourth embodiment.
[Explanation of symbols]
1,1A, 1B Plate cylinder
1a, 1Aa, 1Ba Outer surface of plate cylinder
2,2A, 2B Printing pressure member
3 paper
5,50 Pressure adjusting means (cam)
5a, 50a 1st cam part
5b, 50b 2nd cam part
5c, 50c 3rd cam part
8 Support members
8a one end
8b The other end
9 Cam Follower
35 Guide members
60 Control means
63A, 63B Pressure adjusting means (driving means)
X Paper transport direction

Claims (4)

A printing cylinder, a printing pressure position that is pressed against the outer peripheral surface of the printing cylinder, and a printing pressure member that is displaceable to a separation position that is separated from the outer circumferential surface of the printing cylinder and that is disposed opposite to the printing cylinder. In a printing apparatus that performs printing by pressing the printing pressure member against the outer peripheral surface of the plate cylinder via a sheet,
A driving means for adjusting the pressing force of the printing pressure member against the outer peripheral surface of the plate cylinder, and for displacing the printing pressure member from the separation position to the printing pressure position;
The displacement of the printing pressure member from the separation position to the printing pressure position is stopped at a proximity position where the printing pressure member is close to the outer peripheral surface of the plate cylinder, and the printing pressure member stopped at the proximity position is And a control means for controlling the drive of the drive means so as to be displaced to the printing pressure position and held at the printing pressure position . A printing cylinder, a printing pressure position that is pressed against the outer peripheral surface of the printing cylinder, and a printing pressure member that is displaceable to a separation position that is separated from the outer circumferential surface of the printing cylinder and that is disposed opposite to the printing cylinder. In a printing apparatus that performs printing by pressing the printing pressure member against the outer peripheral surface of the plate cylinder via a sheet,
Adjusting the pressing force of the printing pressure member against the outer peripheral surface of the plate cylinder, comprising a cam for displacing the printing pressure member from the separation position to the printing pressure position;
The cam includes a first cam portion that holds the printing pressure member in a proximity position close to the outer peripheral surface of the plate cylinder when the printing pressure member is displaced from the separation position to the printing pressure position, and the printing cam. A printing apparatus comprising: a second cam portion that displaces the pressure member from the proximity position to the printing pressure position; and a third cam portion that holds the printing pressure member at the printing pressure position . The printing apparatus according to claim 2, wherein
A swingable support member provided with a cam follower in contact with the first cam portion, the second cam portion, and the third cam portion at one end, and the printing pressure member supported at the other end ;
A printing apparatus comprising: a guide member that guides the cam follower so as to be movable along the third cam portion from the first cam portion . The printing apparatus according to any one of claims 1 to 3 ,
A printing apparatus, wherein a plurality of the plate cylinders and the printing pressure members are arranged in parallel from the upstream side to the downstream side in the paper transport direction .

Images