JP2000033756A - Ink ribbon cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink ribbon cassette which can stably run a ribbon used in a thermal printer or the like, thereby maintaining a high print quality. SOLUTION: This ink ribbon cassette has ribbon slack prevention ribs 28. When the ink ribbon cassette is mounted to a thermal printer and printing is carried out, a ribbon is supplied from a ribbon pan cake 22 to a printing head 3. When each line is finished to be printed, the ribbon pan cake 22 having an inertia at the print time is braked by a resistance to the ribbon slack prevention ribs 28, so that a slack of the ribbon is restricted. A ridge of the ribbon slack prevention rib 28 in a radial direction of the ribbon pan cake 22 is chamfered and therefore a damage to an end face of the ribbon can be limited. Moreover, the ribbon slack prevention ribs 28 are disposed not to overlap with a ribbon take-out path of the ribbon pan cake 22, thus preventing a take-out tension from varying.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thinning mechanism for an ink ribbon cassette used in a thermal printer or the like.

[0002]

2. Description of the Related Art In a thermal printer which performs printing using an ink ribbon (hereinafter referred to as a ribbon) mounted in a cassette, an ink ribbon pancake (hereinafter referred to as a ribbon pancake) is obtained when a carriage stops at the end of a printing line during printing. May rotate more than necessary due to inertia, and the ribbon may become loose. This slack is suddenly absorbed at the start of the printing operation of the next line, so that the load for pulling out the ribbon increases instantaneously, causing ribbon sticking, printing dirt, and misalignment of ruled lines. Driving and printing quality are hindered.

In order to prevent the ribbon from being loosened due to excessive rotation of the ribbon pancake, a load is always applied to the rotation axis of the ribbon pancake using a spring or the like. However, in this method, the ribbon is unwound and the winding diameter of the ribbon pancake is reduced, so that the load of pulling out the ribbon is increased and a running defect such as a ribbon stick may occur. That is, in a ribbon pancake whose winding diameter varies, it is difficult to prevent slack or poor running only by the strength of the spring pressure that applies a constant load to the rotating shaft. In addition, 2-228
In the ink ribbon cartridge disclosed in Japanese Patent Publication No. 57, a separate spring is provided to prevent the ribbon from being slackened. However, when the printing speed is increased, the effect of removing the slack of the ribbon is limited due to the inertia of the ribbon pancake. In addition, there is a problem that the cost is increased due to disposing another part.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an ink ribbon cassette in which a ribbon used for a thermal printer or the like can be stably moved and high print quality can be maintained. Aim.

[0005]

According to a first aspect of the present invention, there is provided an ink ribbon pancake which can be mounted on a carriage of a printer, and has an ink ribbon wound around a core, and which responds to the carriage moving operation of the printer. The ink ribbon from the ink ribbon pancake to allow the printer to print by running the print head of the printer. By providing a rib having an abutting surface for abutting and providing frictional resistance, it is possible to prevent the ink ribbon from being unnecessarily loosened during operation of the printer.

According to a second aspect of the present invention, in the first aspect of the present invention, the rib is provided so as to contact the ribbon pancake.

According to a third aspect of the present invention, in the first or second aspect, the rib is formed integrally with the cassette housing.

A fourth aspect of the present invention is characterized in that, in the second or third aspect of the invention, the contact between the ink ribbon pancake and the rib is obtained by the weight of the ink ribbon pancake. Things.

According to a fifth aspect of the present invention, in the invention of any one of the second to fourth aspects, the maximum allowable slack amount of the ink ribbon at the end of printing of each line is determined based on the running length of the head in each printing line. And, based on the amount of slack of the ribbon at the end of printing, which varies depending on the winding diameter of the ink ribbon pancake wound on the core, the ink in the ribs so as not to exceed the maximum allowable slack at least. The present invention is characterized in that a contact area with a ribbon pancake is set.

According to a sixth aspect of the present invention, in any one of the second to fifth aspects of the present invention, the surface of the rib that abuts on the ink ribbon extends further outside the maximum diameter of the ink ribbon pancake. It is characterized by having been configured as described above.

According to a seventh aspect of the present invention, in any one of the second to sixth aspects, a contact surface of the rib with the ink ribbon pancake is higher in a height direction than a support surface on which the core is supported. It is characterized by being set at the position.

According to an eighth aspect of the present invention, in the invention of any one of the first to seventh aspects, at least a part of a ridge line of the rib is chamfered.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects of the present invention, the rib has a slope whose height gradually decreases in a radial direction of the ink ribbon pancake. is there.

According to a tenth aspect of the present invention, in any one of the second to ninth aspects of the present invention, the rib is disposed so as not to come into contact with the ink ribbon running away from the ink ribbon pancake. It is characterized by the following.

The invention of claim 11 is the invention of claims 1 to 10
Any one of the inventions is characterized in that the contact surface of the rib is selectively subjected to a surface treatment to adjust a frictional resistance with the ink ribbon pancake.

The twelfth aspect of the present invention provides the first to eleventh aspects.
In any one of the inventions, the rib is provided radially with respect to a rotation axis of the core.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a thermal printer which performs printing using an ink ribbon mounted in a cassette. When a carriage stops at the end of a printing line during printing, a ribbon pancake rotates by inertia. In order to prevent the slack of the ribbon caused by too much, the inertia of the ribbon pancake should be adjusted so that the ribbon slack amount at the end of printing of at least one line is smaller than the head running amount (running amount) before printing of the next line. By providing a rib having a function of stopping in the ribbon cassette, the ribbon stick, the printing dirt, and the displacement of the ruled line are prevented, so that the ribbon can be satisfactorily run.

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. Note that in all the drawings for describing the embodiments, the same elements and portions having similar functions are denoted by the same reference numerals, and repeated description thereof will be omitted. FIG. 1 is a configuration diagram of an example of a printer device to which the present invention is applied. In the drawing, 1 is a ribbon cassette, 2 is a ribbon take-up mechanism, 3 is a print head for performing printing,
Reference numeral 10 denotes a printer unit for performing printing, 11 denotes a carriage unit to which the ribbon cassette 1 can be attached and detached, 13 denotes a carriage motor, 14 denotes a timing belt, 15 denotes a platen roller for feeding print paper, 16 denotes a platen,
26 is a winding core. Carriage unit 11
Is provided so as to be movable in parallel to the platen 16 by driving the timing belt 14 by the rotation of the carriage motor 13. The print head 3 and the ribbon winding mechanism 2 are provided in the carriage unit 11.

Next, the details of the present invention will be described with reference to FIGS. FIG. 2 is a plan view for explaining an embodiment of the ink ribbon cassette according to the present invention. In the drawing, reference numeral 21 denotes a core (unwinding core), reference numeral 22 denotes a ribbon pancake, and reference numeral 23 denotes a tip with a felt attached. Leaf spring, 24
Is a guide roller, 27 is a slack removing spring, and 28 is a ribbon slack preventing rib. FIG. 3 is a side view of the ink ribbon cassette shown in FIG. 2, in which 22e is the outer diameter of the ribbon pancake, 22i is the pancake diameter at which the slack of the ribbon is smaller than the amount of the next run, and 28e is the ribbon pancake. The contact surface outer end, 28i is the ribbon pancake contact surface inner end,
28s is a gradient, and f is a core support surface. FIG. 4 is a side view of a main part for explaining a configuration example of a ribbon slack preventing rib according to the present invention. FIGS. 4A and 4B show a structural example of a ribbon slack preventing rib having a different chamfered shape. ).

In the ink ribbon cassette shown in FIG. 2, an unused ribbon pancake 22 wound on a core 21 is used.
The print head 3 is provided with an appropriate back tension by a leaf spring 23 having a felt attached to the tip thereof, and via a guide roller 24 provided rotatably with respect to a pin formed integrally with the ribbon cassette case. It travels along and is taken up by the take-up core 26. Further, a slack removing spring 27 is provided to remove the slack of the ribbon when the print head 3 finishes printing and the print head 3 heads up due to an operation such as carriage return.

The ribbon slack preventing rib 28 is formed integrally with the ribbon cassette in the following state. (1) Arranged so as not to overlap the ribbon pull-out path from the ribbon pancake (see FIG. 2). (2) The unwinding core 21 is set higher than the support surface f supported in the height direction in the cassette, and the ribbon pancake 2
2 comes into contact with the ribbon slack preventing rib by its own weight (see FIG. 3). (3) After the printing of at least one line is completed, the position of the inner end portion 28i of the ribbon slack prevention rib 28 on the ribbon pancake contact surface is adjusted so that the ribbon slack amount is smaller than the head running amount before the start of printing of the next line. After the determination, the outer end 28e of the ribbon pancake contact surface is set at least outside the ribbon pancake having the outer diameter 22e (see FIG. 3). (4) The ribbon pancake contact surface inner end 28
A slope 28s is provided so that the height of the ribbon slack preventing rib 28 gradually decreases toward the inside from i (see FIG. 3). (5) Chamfer the ridge line of the ribbon slack prevention rib 28 corresponding to the radial direction of the ribbon pancake 22 (see FIG. 4).

When the ribbon cassette is mounted on a thermal printer and printing is performed, the ribbon pancake 22 supplies the ribbon to the thermal head in synchronization with the printing length. At the end of printing, the ribbon pancake 22 having inertia at the time of printing is braked by resistance against the ribbon slack preventing rib 28, and the ribbon slack is suppressed. At this time, the ribbon slack prevention rib 28 is attached to the ribbon pancake 2.
Since the radial ridge line 2 is chamfered, damage to the end face of the ribbon can be suppressed. In addition, since the ribbon slack preventing rib 28 is arranged so as not to overlap with the ribbon drawing path of the ribbon pancake 22, the tension of the drawing does not vary.

Using the ribbon cassette according to the present invention and the conventional ribbon cassette, the amount of slack of the ribbon with / without the ribbon slack preventing rib was measured while changing the diameter of the ribbon pancake in the ribbon cassette. Table 1 shows the results.
FIG. 5 is a graph showing the evaluation results shown in Table 1.

[0024]

[Table 1]

Three ribbon slack preventing ribs 28 are arranged radially from the core of the core 21 around which the ribbon pancake 22 is wound, and the distance from the core to the outer end 28e of the ribbon pancake contact surface is 21. 5 mm, and the distance from the core to the inner end 28i of the ribbon pancake contact surface was set to 15 mm. The outer diameter 22e of the ribbon pancake 22 was 32 mm. The printing speed in the evaluation is 100 cp
s (equivalent to 400 DPI 56 DOTS / character, 356 m
m / sec). As shown in FIG. 5, when the outer diameter of the ribbon pancake 22 exceeds 30 mm, it can be seen that the slack of the ribbon after the printing of the present invention is reduced by half compared to the related art. In the printer used in this experiment, the approach distance before printing was set to 8 mm, and it was possible to start printing after sufficiently removing the slack of the ribbon.

Therefore, when the ribbon slack preventing rib 28 is not provided, the ribbon slack exceeds the run-ahead amount before printing on the printer (ie, the run-up portion cannot absorb all the ribbon slack), which corresponds to the winding diameter of the ribbon pancake 22. It is preferable to provide the ribbon pancake contact surface of the ribbon slack prevention rib 28 only at the portion where the ribbon slack is prevented, and at the portion further inward from the ribbon pancake contact surface inner end 28i, the height of the rib is reduced. A slope 28s is provided by gradually decreasing the slope.

Further, by performing etching and surface treatment on the ribbon slack preventing rib 28, the frictional resistance to the ribbon can be adjusted, and the slack amount of the ribbon can be optimized.

[0028]

According to the first aspect of the present invention, by providing the ribbon slack preventing rib in the ribbon cassette, the running of the ribbon is stabilized, and a good print quality can be obtained without causing ribbon sticking, printing dirt, and printing misalignment. Obtainable.

According to the second aspect of the present invention, in addition to the effect of the first aspect, the ribbon running is further stabilized by contacting the ribbon slack preventing rib with the ink ribbon against the ribbon pancake. Can be.

Effect of Claim 3 In addition to the effect of Claim 1 or 2, by providing the ribbon slack preventing rib integrally with the ribbon cassette housing, the ribbon cassette can be constructed at low cost, and the present invention can be rationally implemented. Can be implemented.

Effect of Claim 4 In addition to the effect of Claim 2 or 3, in addition to the structure in which the inertia is stopped by utilizing the own weight of the ribbon pancake, the ribbon cassette can be constructed at a low cost and can be rationally implemented. The invention can be implemented.

According to the fifth aspect of the present invention, in addition to the effect of any one of the second to fourth aspects, by optimizing the contact position of the ribbon slack preventing rib with the ribbon pancake based on the head running amount of the next line. When the ribbon diameter of the ribbon pancake becomes small near the end of the ribbon, it is possible to prevent an excessive increase in the pull-out load, stabilize the running of the ribbon, and perform good printing without causing ribbon sticking and printing dirt. Quality can be obtained.

Effect of Claim 6: In addition to the effect of any one of Claims 2 to 5, in addition to the fact that the contact surface of the rib for preventing slack is further extended outside the outer diameter of the ribbon pancake, printing is performed. Even when the core is displaced in the radial direction in the cassette case, the stability of the load between the ribbon pancake and the ribs can be maintained, there is no ribbon sticking or printing dirt, the running of the ribbon is stable, and good Print quality is obtained.

According to a seventh aspect of the present invention, in addition to the effect of any one of the second to sixth aspects, the height of the ribbon slack preventing rib is made higher than the supporting surface of the core in the cassette case, so that the ribbon pancake and the rib are prevented. Can be reliably brought into contact with each other, and the running of the ribbon can be stabilized.

Effect of Claim 8 In addition to the effect of any one of Claims 1 to 7, by chamfering the ribs of the slack preventing ribbon, it is possible to prevent the end face of the ribbon from being damaged. And good print quality can be obtained.

Effect of Claim 9 In addition to the effect of any one of Claims 1 to 8, in addition to the effect of the diameter of the ribbon pancake, a gradient in which the height of the slack preventing rib gradually decreases as the diameter decreases becomes smaller. By providing the ribbon, it is possible to obtain a good print quality without damaging the ribbon on the side surface of the rib, stabilizing the load, and without causing the ribbon sticking and the printing stain.

Effect of Claim 10 In addition to the effect of any one of Claims 2 to 9, the running of the ribbon is prevented by preventing the ribbon drawing path from the ribbon pancake from being overlapped with the arrangement position of the rib. Good print quality can be obtained stably without causing ribbon sticking or printing stains.

Effect of Claim 11: In addition to the effect of any one of Claims 1 to 10, the surface of the rib for preventing slack is partially subjected to surface treatment to adjust the frictional resistance between the ribbon pancake and the rib. As a result, a desired pulling load can be obtained, the running of the ribbon is stabilized, and good print quality can be obtained without the occurrence of ribbon sticking and printing stains.

Effect of Claim 12 In addition to the effect of any one of Claims 1 to 11, a reasonable arrangement of the slack preventing ribs is provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an example of a printer device to which the present invention is applied.

FIG. 2 is a plan view illustrating an embodiment of an ink ribbon cassette according to the present invention.

3 is a side view of the ink ribbon cassette shown in FIG. 2;

FIG. 4 is a side view of a main part for describing a configuration example of a ribbon slack prevention rib according to the present invention.

FIG. 5 is a graph showing the evaluation results of the ink ribbon cassette of the present invention mounted on a thermal printer, together with the evaluation results of a conventional ribbon cassette.

[Explanation of symbols]

1. Ribbon cassette, 2. Ribbon winding mechanism, 3.
Print head, 10 printer unit, 11 carriage unit, 13 carriage motor, 14 timing belt, 15 platen roller, 16 platen, 2
1 ... core (unwinding core), 22 ... ribbon pancake,
22e: Ribbon pancake outer diameter, 22i: Ribbon pancake diameter, in which the slack of the ribbon is smaller than the next running amount, 23
... A leaf spring with a felt attached to the tip, 24... A guide roller, 26... A take-up core, 27.
... Ribbon slack preventing ribs, 28e ... Ribbon pancake contact surface outer end, 28i ... Ribbon pancake contact surface inner end, 28s ... Slope, f ... Core support surface.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shunichi Hayashiyama 22-22, Nagaike-cho, Abeno-ku, Osaka-shi, Osaka F-term (reference) 2C068 AA01 AA05 AA15 EE03 EE98 FF01 FF07 FF12 FF13 HH00 HH04 HH12 HH20

Claims (12)

[Claims] 1. An ink ribbon pancake which can be mounted on a carriage of a printer and has an ink ribbon wound around a core, and sends out the ink ribbon from the ink ribbon pancake in accordance with the carriage moving operation of the printer. An ink ribbon cassette that enables printing by the printer by running a print head unit of the printer, and a contact surface that applies frictional resistance by contacting the ink ribbon at a position before reaching the head unit. An ink ribbon cassette provided with a rib having the following so as to prevent the ink ribbon from being unnecessarily loosened during operation of the printer. 2. The ink ribbon cassette according to claim 1, wherein said rib is provided so as to contact said ribbon pancake. 3. The ink ribbon cassette according to claim 1, wherein said rib is formed integrally with a cassette housing. 4. The ink ribbon cassette according to claim 2, wherein the ink ribbon pancake and the rib come into contact with each other by the weight of the ink ribbon pancake. 5. The ink ribbon cassette according to claim 2, wherein a maximum allowable slack amount of the ink ribbon at the end of printing of each line is determined based on a running length of the head in each printing line. The ink ribbon pancake in the ribs is controlled so as not to exceed the maximum allowable slack amount at least based on the ribbon slack amount at the end of the printing which varies depending on the winding diameter of the ink ribbon pancake wound on the core. An ink ribbon cassette for setting an abutting area with the ink ribbon cassette. 6. The ink ribbon cassette according to claim 2, wherein a surface of the rib that abuts on the ink ribbon extends further outside a maximum diameter of the ink ribbon pancake. An ink ribbon cassette characterized by comprising: 7. The ink ribbon cassette according to claim 2, wherein a contact surface of the rib with respect to the ink ribbon pancake is set at a position higher in a height direction than a support surface on which the core is supported. An ink ribbon cassette, comprising: 8. The ink ribbon cassette according to claim 1, wherein at least a part of a ridge line of the rib is chamfered. 9. The ink ribbon cassette according to claim 1, wherein the rib has a slope whose height gradually decreases in a radial direction of the ink ribbon pancake. 10. The ink ribbon cassette according to claim 2, wherein the rib is arranged so as not to come into contact with the ink ribbon running away from the ink ribbon pancake. Ink ribbon cassette. 11. The ink ribbon cassette according to claim 1, wherein a surface treatment is selectively performed on the contact surface of the rib to adjust a frictional resistance with the ink ribbon pancake. Ink ribbon cassette. 12. The ink ribbon cassette according to claim 1, wherein the ribs are provided radially with respect to a rotation axis of the core.