GB2033872A - Reinking of endless ink ribbon cartridges - Google Patents

Abstract

To reink the endless ribbon 7 of an endless ink ribbon cartridge there is provided a re-inking device 23 comprising a housing from which extends an inking wick 29, a pressure element 25 and means 30,31 for attaching the device 23 to the cartridge. The combination of cartridge and device is such that when the device is attached, the inking wick 29 engages an inking roller 12 of the cartridge and the pressure element 25 urges and maintains the ribbon 7 into engagement with the inking roller 12 and such that a limited relative angular rotation is permitted between the cartridge and device 23 so that in use variations in ribbon tension are sensed by the pressure element 25 to vary the contact pressure of inking wick 29 on the inking roller 12. <IMAGE>

Description

SPECIFICATION Reinking of endless ink ribbon cartridges This invention relates to the reinking of endless ink ribbon cartridges such as used in typewriters, teleprinters and high speed printers for data processing systems. An example of an endless ink ribbon cartridge is to be found in the specification of our British Patent No. 1502760.

According to the present invention, there is provided the combination of an endless ink ribbon cartridge comprising a housing, an endless ink ribbon located mainly within said housing with a portion extending externally thereof, a ribbon driving roller within said housing and an inking roll engaging the ribbon upstream of said roller; and a re-inking device comprising a housing from which extends an inking wick, a pressure element and connection means for permitting the attachment of the device to the cartridge, the combinaton being such that when the device is attached to the cartridge the inking wick engages the inking roll and the pressure element urges the ribbon into engagement with the inking roll, and such that a limited relative angular rotation is permitted between the cartridge and the device so that in use variations in ribbon tension are sensed by the pressure element to vary the contact pressure of the inking wick on the inking roll.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure lisa perspective view of the combination according to the invention of an ink ribbon cartridge minus its cover, and an inking device for attachment thereto, Figure 2 is a top view of a portion of the ink ribbon cartridge of Figure 1, Figure 3 is a top view of the same portion of the ink cartridge of Figure 2 and an inking device lying under the same portion of cartridge and attached thereto, and Figure 4 is a top view of the same portion on the ink ribbon cartridge of Figure 2 and an inking device lying under this portion and placed in work position.

Referring to the drawings, the ink ribbon cartridge 1 comprises a plastics body which has a flat bottom wall 2 and side walls 3,4,5 and 6 forming a nearly rectangular housing or reservoir in which an ink ribbon 7 is randomly stored. The flat bottom wall 2 and the side walls 4, 5 and 6 extend upwardly from the bottom wall and combine to form two arms 8 and 9 having an external side walls 5A and 6A respectively and an internal side walls 4A and 4B respectively. The internal and external side walls are nearly parallel to each other and form two slots or recesses 10, 11 which communicate with the interior of the housing.

The path of the ribbon is such that it extends externally of the cartridge from slot 10to slot 11 where it re-enters the cartridge for engagement by an idler inking roll 12 rotatable about pin 17 and a drive roller 13 associated with a pressure spring 14.

Atension or ribbon brake spring 15 located in arm 8 ensures that the portion of the ribbon between the drive 13 and spring 15 is held under tension.

A printing head, shown as block 16, acts on the ribbon 7 in the zone comprised between the two arms 8 and 9, compressing it against a printing support, not shown, to which the ribbon ink is transferred, hence leaving a mark with the configuration determined by the printing head (of the dot printing type or of the solid font selection type or of the type having a printing hammer reciprocating against an opposed platen having type fonts in abutement thereon). The cartridge bottom wall 12 is provided with suitable openings 18 and 20 near the ink roll 12 to allow the attachment onto the cartridge of an external re-inking device 23. Opening 18 comprises portion 18A extending generallytrans- verse of the ribbon direction entering arm 9, and portion 1 8B extending perpendicularly to portion 18A toward roll 12.

Referring to Figure 2, the opening portion 18A has a greater length in the X direction and opens on the right of the path of the ink ribbon 7 which enters the arm 9 through two guides 21,22 (constituting the ends of the walls 4B and 6A) and which extends diagonally towards and over the roll 12. Opening portion 18B extends along the Y direction from the portion 18A and is mainly located on the left hand side of the ribbon. The roll 12 projects partly over the end region of opening portion 18B as seen in Figure 2. The opening 20 extends in the Y direction and is aligned with the opening portion 18B; opening 20 has a variable width section varying from a maximum in zone 20A to a minimum in zone 20B with communicates with a circular zone 20C.

Reconsidering Figure 1, the reinking device consists of parallelepiped form container, hollow inside and containing reinking ink. This container can be easily obtained by plastic molding of two half shells.

When attached to the cartridge 1, the left hand portion (identified by the dashed rectangle 24) of device 23 engages and mates with the lower face or bottom of arm 9. Both faces are suitably flat.

Extending upwardly from the upper face of the device is a retaining tooth 25, intended for insertion into the opening 18. The under surface 26 of tooth 25 is spaced a distance from the device top face which is slightly greater than the thickness of the bottom wall of arm 9 to enable easy insertion of the tooth into opening 18. Also extending upwardly from the upper face of the device is a pressure compensation tube 27 (which communicates with the internal cavity of the device), a retaining element 28 for a felt cylindrical inking wick 29 and a retaining pin 30. The retaining element 28 in the form of a part-cylindrical tube segment has the function of containing and holding the wick 29, which penetrates into the interior of device 23 and draws by capillary action the ink upto the exposed part of the wick, and which in use is in pressure contact with the inking roll 12.

The diameter of element 28 is smaller by some millimeters than the width of opening portion 18B and the retaining pin 30 has a diameter somewhat less than the width of the wider portion 20A of opening 20 so as to be easily inserted therein.

Moreover, the pin 30 has an undercut circular groove, whose height is equal to the thickness of the bottom wall of arm 9 and whose internal diameter is equal or a little less than the diameter of circular zone 20C.

The relative positions of tooth 25, element 28 and pin 30 are such as to allow the simultaneous insertion of these eiements into corresponding ones of opening portions 18A, 18B and opening 20.

The Figure 3 represents in plan the reinking device underlying the ribbon cartridge arm 9 and presented thereto with tooth 25 located in opening portion 18A, element 28 located in portion 18B and pin 30 located in zone 20A of opening 20. In this position, the ink ribbon is interposed between tooth 25 and element 28, an adequate clearance is provided between tooth 25 and wick 29 to allow insertion of the ribbon there between without risk of relative interference.

To bring the cartridge 23 into operative position (shown in Figure 4), the cartridge 23 is shifted in the Y-axis negative direction, so that the groove 31 of pin 30 is positioned in the circular zone 20C of opening 30, the pin head preventing the pin's axial withdrawing from the opening. Likewise under surface 26 of the tooth 25 is brought into engagement with the bottom surface of the ribbon cartridge and the tooth comes into contact with the ink ribbon tending to deflect it as indicated in Figure 4. At the same time the wick 29 moves against the inking roller 12. It is evident that the ink ribbon in tension exerts a pressure on side 32 of tooth 25 which pressure tends to shift laterally the tooth 25 and hence cartridge 23 around the pivot formed by the pin 30.Slight angular rotation is allowed by the clearance existing between the dimensions of the tooth 25 and the element 28 and those of the opening 18. Because of ribbon pressure, the wick 29 comes to contact with inking roll 12 with a contact force proportional and opposite to the torque exerted by the ribbon on the cartridge 23.

It will be apparent that when, during use of ribbon 7, a decline in the cartridge impression quality is detected, it is possible to insert easily the rein king cartridge 23 onto the ribbon cartridge 1 to restore the required quantity of ink on ribbon 7. As the ink ribbon 7 moves into its cartridge, the inking roll 12 is turned by the ribbon and the wick 29 of device 23 contacts the roll 12 to moisten it with an ink film which is subsequently transferred to the ribbon.

It has been experimentally verified that, if certain pressure limits are not exceeded, the ink quantity transferred to the roll 12 from wick 29 is about proportional to the contact pressure between wick 29 and roll 12. It has also been verified that the ink ribbon tension changes approximately proportionally to the degree of ink on tape 7. In other words, an inkless ribbon exerts a greater friction than an inked ribbon and hence imposes a greater ribbon tension on the ribbon upstream of the driving roller 13.

Therefore, in use, the above described reinking device will supply a quantity of ink to the ribbon approximately proportional to that required by the ribbon to be correctly inked. This is because as the ribbon tension increases so that the torque exerted by the same on the reinking cartridge is increased and this torque determines a greater contact pressure between wick and inking roll, causing a greater ink transfer.

Figures 2,3 and 4 shows the presence of a third elongated opening 33 in the bottom wall of arm 9, parallel and proximate to an opening 20. This opening 33 is not strictly necessary but is provided to increase the elasticity of the plastics material near the zone 20B thus allowing the insertion of pin 30 into the circular zone 20C of opening 20 without too much effort.

Claims (3)

1. The combination of an endless ink ribbon cartridge comprising a housing, an endless ink ribbon located mainly within said housing with a portion extending externally thereof, a ribbon driving roller within said housing and an inking roll engaging the ribbon upstream of said rolier; and a re-inking device comprising a housing from which extends an inking wick, a pressure element and connection means for permitting the attachment of the device to the cartridge, the combination being such that when the device is attached to the cartridge the inking wick engages the inking roll and the pressure element urges the ribbon into engagement with the inking roll, and such that a limited relative angular rotation is permitted between the cartridge and the device so that in use variations in ribbon tension are sensed by the pressure element to vary the contact pressure of the inking wick on the inking roll.

2. The combination of Claim 1, wherein the re-inking device includes an ink reservoir, the inking wick obtaining ink therefrom by capillary action, and a pressure compensation opening.

3. The combination of Claim 1 or 2, wherein the connection means includes two openings formed in a wall of the cartridge and two suitably shaped locating members extending from the housing of the device for insertion into the openings, one of said members being provided by the pressure element.