GB2294908A

GB2294908A - Ink feeding device for a printer

Info

Publication number: GB2294908A
Application number: GB9523114A
Authority: GB
Inventors: Kiyoshi Suzuki
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 1994-11-11
Filing date: 1995-11-10
Publication date: 1996-05-15
Anticipated expiration: 2015-11-10
Also published as: GB9523114D0; JPH08132717A; KR0158043B1; KR960017166A; DE19542027A1; GB2294908B

Description

INK FEEDING DEVICE FOR A PRINTER 2294908

BACKGROUND OF THE INVENTION

The present invention relates to an ink feeding device for a printer and, more particularly, to a device for feeding ink to an ink ribbon used with a dot impact printer or similar printer.

An ink feeding device for the above application has an ink retainer impregnated with ink, a container accommodating the ink retainer, a wick held in contact with the ink retainer, and an ink transfer roller for transferring the ink fed from the wick to an ink ribbon. The ink stored in the retainer infiltrates into the wick due to its own infiltration ability. The ink is fed from the wick to the ribbon by way of the transfer roller and a drive roller. This kind of configuration, however, has a drawback that the ink impregnated in the 1 5 retainer, but remote from the wick, cannot be easily fed to the ribbon with the infiltration ability alone, although the ink around the wick can be efficiently fed to the ribbon. Hence, it is impracticable for the ink stored in the retainer to be sufficiently used.

SUMMARY OF THE I1,1VEMION

It is, therefore, an object of at least the preferred embodiments of the present invention to provide an ink feeding device for a printer and capable of efficiently using ink impregnated in an ink retainer.

A device for feeding ink to an ink ribbon of the present invention has an ink retainer adapted to be impregnated with ink, a container accommodating the ink retainer, a wick for feeding the ink to the ink ribbon, and a pressing means for reducing the volume of the ink retainer.

The pressing means may act directly upon the ink retainer, or indirectly by acting upon a displaceable wall of the container.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken with the accompanying drawings, in which:

FIG. 1 is a section showing a first embodiment of the ink feeding device in accordance with the present invention and in a condition before the operation of a pressing member; FIG. 2 is a fragmentary enlarged section showing the embodiment in a condition after the operation of the pressing member; FIGS. 3A and 3B each shows a particular configuration of a rack included in the first embodiment; FIGS. 4, 5 and 6 are sections respectively showing a second, a third and a fourth embodiment of the present invention; and FIG. 7 is a section showing a conventional ink feeding device.

In the figures, the same reference numerals designate the same constituent Parts.

1 5 DESCRIPTION OF THE PREFERRED EMBODIMENTS

To better understand the present invention, a brief reference will be made to a conventional ink feeding device, shown in FIG. 7. As shown, the device, generally 56, has an ink retainer or supply body 58 impregnated with ink, a container 57 accommodating the retainer 58, a wick 59 held in contact with the retainer 58, and an ink transfer roller 66 for transferring the ink fed from the wick 59 to an ink ribbon 52. The entire device 56 is accommodated in a ribbon case 51. Also disposed in the ribbon case 51 are a drive roller 67 contacting the ink transfer roller 66, a driven roller 68 driven by the drive roller 67, a holder 69 holding the driven roller 68, and a spring 70 constantly biasing the roller 68 toward the roller 67. The case 51 has a ribbon passage 53 thereinside, and an opening 55 constituting a portion 54 for inserting a print head 71.

In operation, the ink stored in the ink retainer 58 infiltrates into the wick 59 due to its own infiltration ability. The ink is fed from the wick 59 to the ink ribbon 52 by way of the ink transfer roller 66 and drive roller 67. This kind of configuration, however, has a drawback that the ink impregnated in the retainer 58, but remote from the wick 59, cannot be easily fed to the ribbon 52 with the infiltration ability alone, although the ink around the wick 59 can be efficiently fed to the ribbon 52. Hence, it is impracticable for the ink stored in the retainer 58 to be sufficiently used.

Preferred embodiments of the ink feeding device in accordance with the present invention will be described hereinafter.

lst Embodiment 1 5 Referring to FIG. 1, an ink feeding device embodying the present invention is shown and generally designated by the reference numeral 6. As shown, the device 6 is accommodated in a ribbon case 1. An ink ribbon 2 is implemented as an endless loop which is about several meters long. The excessive portion of the ribbon 2 is received in the case 1 in a folded position, as illustrated. A part of the case 1 is provided with a generally loop-like -configuration, so that it will surround a print head 21 (indicated by a phantom line in FIG. 1) when the case 1 is mounted to a printer, not shown.

This loop-shaped portion of the case I has a ribbon passage 3 1 5 the ink to the ribbon 2 thereinside so as to allow the ribbon 2 to run therethrough.

C- The passage 3 is partly cut off to form a portion 4 for inserting the head 21. The ribbon 3 is partly exposed to the outside through an opening 5 formed in the case 1.

The ribbon 2 is nipped between a drive roller 17 and a driven roller 18 at a single point thereof. The drive roller 17 and driven roller 18 extend parallel to each other. The driven roller 18 is held by a holder 19 and constantly biased by a spring 20 toward the drive roller 17. Hence, a predetermined 1 0 pressure constantly acts between the two rollers 17 and 18.

The device 6 has an ink retainer 8 impregnated with ink.

A container 7 accommodates the retainer 8 therein for protection while preventing ink from leaking to the outside.

0 A wick 9 is held in contact with the retainer 8 so as to f e e d A lever 10 is also held in contact with the retainer 8 and rotatable about a center of rotation The lever 10 is used to press a part of the retainer 8 remote from the wick 9, as will be described specifically later. A rack 14 is formed on the outer periphery of the case 1 in order to lock the presser lever 10 in position. The reference numeral 16 designates an ink transfer roller.

The lever 10 is implemented as a rod or a bar. The container 7, fixed in place in the case 1, has a slot 12 in one side wall thereof. The lever IQ is received in and movable along the slot 12 when rotated about the center of rotation 2 5 11. A rubber seal 13 is fitted on the inner periphery of the container 7 around the slot 12 in order to prevent the ink from leaking through the slot 12. The case 1 also has a slot in one side wall thereof facing the side wall of the container 7 where the slot 12 is present. The slots 12 and 15 are aligned with each other to allow the lever 10 to move therethrough about the center of rotation 11. The rack 14 is located in close proximity to the slot 15.

As shown in FIG. 3A, the rack 14 for locking the lever 10 is implemented by a plurality of lugs extending perpendicular to the slot 15. Alternatively, as shown in FIG. 3B, the rack 14 may be implemented by a plurality of grooves formed in the wall of the case 1 and communicated to the slot 15.

In operation, when a torque is applied to the drive roller 1 5 17 from the outside of the case 1, the roller 17 is rotated while nipping the ribbon 2 between it and the driven roller 19.

As a result, the ribbon 2 is moved along the ribbon passage 3 due to friction. Because the ribbon 2 is exposed to the outside at the portion 4, the head 21 is capable of printing o u t data in contact with the part of the ribbon 2 facing the portion 4. Initially, a sufficient amount of ink exists in the retainer 8. Hence, during the course of printing, the ink sequentially infiltrates into the wick 9 due to its own infiltration ability. The ink transferred to the wick 9 is delivered to the drive roller 17 via the ink transfer roller 16.

Because the ribbon 2 is nipped between the rollers 17 and 18, the ink is adequately fed from the roller 17 to the ribbon 2.

During the course of printing, although the part of the ink adjoining the wick 9 is consumed soon, the part of the ink around the wick 9 is immediately replenished to the wick 9 due to the infiltration ability particular to the ink. However, when the total amount of ink existing in the retainer 8 decreases, the ink remote from the wick 9 fails to infiltrate into the wick 9 with its own infiltration ability alone. This would result in defective images. In the illustrative embodiment, as shown in FIG. 2, the lever 10 contacting the part of the absorbent 8 remote from the wick 9 is moved upward by hand about the center or rotation 11 such that the volume of the retainer 8 decreases. Subsequently, the lever 1 5 10 is locked in position by the rack 14. As a result, the ink density in the absorbent 8 is increased while the ink remote from the wick 9 is moved toward the wick 9. This promotes the infiltration of the ink into the wick 9 and thereby insures adequate ink supply to the ribbon 2, so that the resulting images are free from defects.

In the above embodiment, the lever 10 directly contacts the ink retainer 8. Alternatively, the container 7 may be formed of rubber, resin or similar soft material and pressed by the lever 10. Such a soft case scheme will obviate the leakage of ink and other troubles despite the use of the lever 10.

2nd Embodiment FIG. 2 shows an alternative embodiment of the present invention which reduces the volume of the ink retainer 8 by use of a screw. As shown, this embodiment is different from the first embodiment in that a screw 22 is substituted for the lever 10. Specifically, the screw 22 is formed with a screw-thread on the periphery thereof and inserted into a threaded hole 23 formed in the ribbon case 1. The end of the screw 22 positioned in the case 1 is held in abutment against the container 7.

Assume that the print quality has lowered due to the repeated printing operation. Then, the screw 22 is driven deeper into the case 1 by hand, so that the end of the screw 22 presses the container 7. As a result, the volume of the retainer 8 is reduced, as in the first embodiment While the screw 22 has been shown and described a s pressing the retainer 7, it may directly press the retainer 8, if desired.

3rd Embodiment FIG. 5 shows another alternative embodiment of the present invention which uses an eccentric roller to reduce the volume of the ink retainer 8. As shown, an eccentric roller 2 4 is formed with a through axial bore at a position deviated from the axis of the roller 24. A shaft 25 is received in the through bore and affixed to the roller 24. The shaft 25 is journalled to the ribbon case 1. Initially, the the roller 24 is simply held in contact with the container 7. When the print quality falls due to the consumption of the ink, the shaft 25 is rotated by hand such that the roller 24 presses the container 7. As a result, the volume of the retainer 8 is reduced in the same manner as in the previous embodiments.

Again, the roller 24 may directly press the retainer 8, 1 0 instead of pressing the container 7.

4th Embodiment FIG. 4 shows still another alternative embodiment of the present invention which uses a push-button mechanism t o reduce the volume of the ink retainer 8. As shown, a push 1 5 button 26 is inserted into the ribbon case 1 via a through hole 28 formed in the case 1. A presser member 27 is affixed to the end of the push button 26 disposed in the case 1. When the print quality is lowered due to the repeated printing operation, the push button 26 is inserted deeper into the case 1 by hand. As a result, the presser member 27 presses the container 7 and thereby reduces the volume of the retainer 8.

The push button 26 is locked to the case 1 due to friction acting between the push button 26 and the wall of the through hole 28.

1 0- 1 5 If desired, the presser member 27 may directly press the ink retainer 8, instead of pressing the container 7.

In summary, in accordance with the present invention, an ink feeding device has an ink retainer which can be pressed from the outside. When the retainer is pressed, the volume thereof is reduced to, in turn, increase ink density within the retainer. This promotes the infiltration of ink into a wick and, in addition, allows ink remote from the wick to move toward the wick, thereby enhancing the efficient use of the

1 0 ink. The device of the invention is, therefore, operable over a longer period of time with high print quality than a conventional device for a given amount of ink. Further, the ink retainer can be pressed by a simple and inexpensive arrangement.

Various modifications will become possible for those skilled in the art after receiving the teachings of the present disclosure without departing from the scope thereof.

Each feature disclosed in this specification (which term includes the claims) and/or shown in the drawings may be incorporated In the invention independently of other disclosed and/or illustrated features.

The text of the abstract filed herewith is hereby deemed to be repeated here in full as part of the specification.

1 -1 l_

Claims

CLAINIS

1. A device for feeding ink to an ink ribbon, comprising:

an ink retainer adapted to be impregnated with ink; a container accommodating said ink retainer; a wick for feeding the ink to the ink ribbon; and pressing means for reducing the volume of said ink retainer.

2. A device as claimed in claim 1, wherein said pressing means comprises a lever.

3. A device as claimed in claim 1, wherein said pressing 1 0 means comprises a screw.

4. A device as claimed in claim 1, wherein said pressing member comprises a push-button mechanism.

5. A device as claimed in claim 1, wherein said pressing member comprises an eccentric roller.

6. A printer ribbon cartridge comprising a device as claimed In any preceding claim.

7. A device for feeding Ink to an Ink ribbon, or a cartridge comprising such a device substantially as herein described with reference to Figures 1 to 6 of the accompanying drawings.

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