JPH04238081A - Ink ribbon cassette - Google Patents

Abstract

PURPOSE:To prevent an ink ribbon from meandering or a recording sheet from becoming contaminated by minimizing the variation of tension given to the ink ribbon, even if the ribbon pressing force of a tension application member varies. CONSTITUTION:A cassette case 4 consists of guide members 5, 6 which guide an ink ribbon 1 and tension application members 7, 8 with ribbon pressing parts 7a, 8a which press the ink ribbon 1 against the guide members 5, 6 for applying tension to the ink ribbon 1. The dynamic friction factor of ribbon contact parts 7a, 8a with the ink ribbon 1 is set to 0.25max. and the dynamic friction factor with the ink ribbon is set to 0.15max.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink ribbon cassette, and more particularly to an ink ribbon cassette that can suppress variations in tension even if the ribbon pressing force of a tension applying member that applies tension to the ink ribbon varies. .

0002

[Prior Art] An ink ribbon cassette includes a guide member for guiding an ink ribbon in a cassette case;
It is known that the guide member is provided with a ribbon pressing portion that presses the ink ribbon and a tension applying member that applies tension to the ink ribbon.

The tension applying member prevents the ink ribbon from meandering in the head portion, and is usually made by pasting felt or the like as a ribbon contact portion to the free end of a thin plate-shaped tension spring. It is something.

0004

[Problems to be Solved by the Invention] However, the above-mentioned ink ribbon cassette is difficult to avoid due to slight errors in manufacturing the above-mentioned tension applying member, such as the bending angle of the tension spring, the degree of warping, the thickness of the plate, or the thickness of the felt. If there is an error, the ribbon pressing force of the tension applying member that presses the ink ribbon toward the guide member will vary greatly, and as a result, the tension applied to the ink ribbon will fluctuate.
For example, if the tension becomes too weak, the ink ribbon may meander in the head, or if the tension becomes too strong, the speed at which the ink ribbon passes through the head becomes slow.
There are drawbacks such as the occurrence of so-called background stains that stain the recording paper.

Therefore, it is an object of the present invention to suppress fluctuations in the tension applied to the ink ribbon to a small level even if the ribbon pressing force of the tension applying member changes, thereby preventing the ink ribbon from meandering or staining the recording paper. To provide an ink ribbon cassette free from the risk of damage.

[0006]

[Means for Solving the Problems] As a result of intensive research in order to solve the above problems, the present inventors have focused on the coefficient of kinetic friction between the tension applying member and the guide member and the ink ribbon, and have set the coefficient of kinetic friction below a specific value. It has been found that by doing so, even if the ribbon pressing force of the tension applying member fluctuates greatly, fluctuations in the tension applied to the ink ribbon can be suppressed to a small level.

The present invention has been made based on the above knowledge, and includes a cassette case that includes a guide member that guides the ink ribbon and a ribbon pressing portion that presses the ink ribbon against the guide member, and applies tension to the ink ribbon. In the ink ribbon cassette, the coefficient of dynamic friction between the ribbon contact portion and the ink ribbon is set to 0.25 or less, and the coefficient of dynamic friction between the guide member and the ink ribbon is set to 0. To provide an ink ribbon cassette characterized in that the ink ribbon is .15 or less.

[0008]

[Operation] According to the ink ribbon cassette of the present invention, the coefficient of dynamic friction between the ribbon contact portion and the ink ribbon is set to 0.25 or less, and the coefficient of dynamic friction between the guide member and the ink ribbon is set to 0.15 or less. Even if the ribbon pressing force of the tension applying member fluctuates greatly due to manufacturing errors or the like, fluctuations in the tension applied to the ink ribbon can be suppressed to a small level.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the ink ribbon cassette of the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment of the ink ribbon cassette of the present invention, FIG. 1 is a plan view showing the inside of the cassette, FIG. 2 is an enlarged plan view of the main parts, and FIG. 3 is a diagram showing the ribbon pressing force and It is a graph showing the relationship with tension.

The ink ribbon cassette of this embodiment is shown in FIG.
As shown in the figure, a cylindrical guide for guiding the ink ribbon 1 is located at the left and right positions on the front side of the cassette case 4, which rotatably houses a pair of take-up/supply hubs 2 and 3 on which the ink ribbon 1 is wound. members 5 and 6, and thin plate-like tension springs 7 and 8 as tension applying members that press the ink ribbon 1 and apply tension to the ink ribbon 1 on the guide members 5 and 6 side, and At a central position on the front side of the cassette 4, there is an arc-shaped guide member 9 that guides the ink ribbon 1, and a thin plate-like slack remover that presses the ink ribbon 1 against the guide member 9 side. It is configured by arranging a spring 10.

[0012] Here, the tension springs 7, 8
A ribbon contact portion 7a made of felt or the like that presses the ink ribbon 1 toward the guide members 5 and 6 is provided at the free end of the ribbon contact portion 7a.
, 8a are attached. Further, a ribbon abutting portion 10a made of felt or the like is also attached to the free end of the slack removing spring 10.

[0013] It should be noted that near one end of the front surface of the cassette 4 (
The print head (thermal head) 1
A recess 4a facing the ink ribbon 1 is formed, and at one end of the recess 4a (on the right side in FIG. 1) there is an outlet 4 through which the ink ribbon 1 temporarily exits the cassette 4 and enters the recess 4a.
b is formed, and the other end side of the recess 4a (left side in FIG. 1)
An entrance portion 4c is formed in the cassette 4 for the ink ribbon 1 to enter the cassette 4 again from the recess 4a. Further, the ribbon contacting portion 10a is located on the guide portion 9 side when not printing, but is separated from the guide portion 9 as shown in FIG. 1 during printing when the ink ribbon 1 runs. Further, a protrusion 4d is provided on the inner surface of the cassette 4 at a central position on the front side to stop the swinging caused by the slack removing spring 10 pressing the ink ribbon 1 while it is running.

The above structure is almost the same as that of the conventional ink ribbon cassette, but the ink ribbon cassette of this embodiment can maintain the above-described pressure force even if the ribbon pressing force of the tension springs 7 and 8 varies greatly due to manufacturing errors or the like. The present invention is characterized in that fluctuations in the tension applied to the ink ribbon 1 can be suppressed to a small level, and there is no risk of the ink ribbon 1 meandering or staining the recording paper.

That is, the coefficient of dynamic friction at the contact surface between the ribbon contact portions 7a, 8a and the ink layer 1a of the ink ribbon 1 is set to 0.25 or less, preferably 0.15 to 0.21.
The dynamic friction coefficient at the contact surface between the guide members 5, 6 and the back coat layer 1b of the ink ribbon 1 is set to 0.15 or less, preferably 0.06 to 0.12.

Here, the coefficient of dynamic friction at the contact surface between the ribbon abutting portions 7a, 8a and the ink layer 1a of the ink ribbon 1 is set to 0.25 or less, and the guide members 5, 6 and the ink ribbon The reason why the coefficient of dynamic friction at the contact surface with the back coat layer 1b of No. 1 is set to 0.15 or less is that when these coefficients of dynamic friction become larger than the above numerical values, the above-mentioned This is because the tension applied to the ink ribbon 1 varies greatly.

According to the ink ribbon cassette of this embodiment constructed as described above, even if the ribbon pressing force of the tension springs 7 and 8 varies greatly due to manufacturing errors, the variation in the tension applied to the ink ribbon 1 can be suppressed. As a result, there is no risk of the ink ribbon 1 meandering or staining the recording paper.

FIG. 3 is a graph showing the relationship between the tension of the ink ribbon 1 (ribbon draw-out tension gf) and the ribbon pressing force (gf) of the tension springs 7 and 8. In the graph of FIG. 3, the dynamic friction coefficient at the contact surface between the ribbon contact parts 7a, 8a and the ink layer 1a of the ink ribbon 1 is set to 0.18, and the back of the guide members 5, 6 and the ink ribbon 1 is shown. The dynamic friction coefficient of the embodiment of the present invention (see solid line A in the same graph) in which the coefficient of dynamic friction at the contact surface with the coating layer 1b is set to 0.09 and the contact surface between the ribbon contact portion and the ink layer of the ink ribbon. coefficient is 0.29
Also shown is a conventional commercially available product (see solid line B in the same graph) in which the coefficient of dynamic friction at the contact surface between the guide member and the back coat layer of the ink ribbon is 0.17.

In the graph of FIG. 3, the ribbon pull-out tension (gf) of the ink ribbon 1 is plotted on the vertical axis, and the ribbon pressing force (gf) of the tension springs 7 and 8 is plotted on the horizontal axis.

Further, in the embodiment of the present invention, as the ink ribbon 1, on one side of a PET film having a thickness of 3.5 μm,
After applying oxidized polyethylene wax, polyether resin, carbon, and ethylene-vinyl acetate copolymer are applied thereon to form an ink layer 1a, and on the other side, silicone acrylic resin and amino-terminated silicone oil are applied. Back coat layer 1 is coated with
The one formed by b was used. Further, the tension springs 7 and 8 were made of stainless steel (SUS304) with a thickness of 0.07 mm. Furthermore, the ribbon contact parts 7a and 8a were made of wool. Furthermore, the guide members 5 and 6 were made of ABS resin.

In the case of the product according to the present invention, the ink ribbon 1
Ribbon drawer tension and tension spring 7
, 8, the slope of the solid line A showing the relationship with the ribbon pressing force was small. That is, even if the ribbon pressing force of the tension springs 7 and 8 varied greatly, the variation in the ribbon pulling tension of the ink ribbon 1 was suppressed to a small level. For example, even if the ribbon pressing force of the tension springs 7 and 8 varies by 9 gf, the tension of the ink ribbon 1 varies by 5 gf.
It was suppressed within the range of 10 gf, that is, within the range in which the ink ribbon 1 did not meander and so-called scumming did not occur, allowing good printing. Note that when the tension of the ink ribbon 1 is less than 5 gf, meandering of the ink ribbon 1 occurs, and when the tension of the ink ribbon 1 is more than 10 gf, so-called scumming occurs.

On the other hand, in the case of the conventional commercially available ink ribbon cassette as a comparative example, the slope of the solid line B indicating the relationship between the ribbon pull-out tension of the ink ribbon and the ribbon pressing force of the tension spring was large. That is, even if the ribbon pressing force of the tension spring varied slightly, the ribbon pull-out tension of the ink ribbon 1 varied greatly. For example, when the ribbon pressing force of the tension spring fluctuated more than 3.5 gf, the ink ribbon tension fluctuated beyond the range of 5 gf to 10 gf.

The ink ribbon cassette of the present invention is not limited to that shown in the above embodiments, but the important point is that the coefficient of dynamic friction between the ribbon contact portion and the ink ribbon is 0.25 or less, and the guide member and the ink ribbon are It is sufficient if the coefficient of dynamic friction with the ribbon is 0.15 or less.

[0024]

As explained above, the ink ribbon cassette of the present invention can suppress fluctuations in the tension applied to the ink ribbon to a small extent even if the ribbon pressing force of the tension applying member varies greatly, and the ink ribbon can be prevented from meandering. There is no risk of staining or staining the recording paper.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the inside of the cassette.

FIG. 2 is an enlarged plan view of main parts.

FIG. 3 is a graph showing the relationship between ribbon pressing force and tension.

[Explanation of symbols]

1 Ink ribbon 1a Ink layer 1b Back coat layer 4 Cassettes 5, 6 Guide members 7, 8 Tension applying members (tension springs) 7a, 8a Ribbon contact portion

Claims (1)

[Claims] 1. A cassette case is provided with a guide member that guides the ink ribbon, and a tension applying member that has a ribbon pressing portion that presses the ink ribbon on the guide member and applies tension to the ink ribbon. In the ink ribbon cassette, the coefficient of dynamic friction between the ribbon contact portion and the ink ribbon is set to 0.25 or less, and the coefficient of dynamic friction between the guide member and the ink ribbon is set to 0.25 or less.
An ink ribbon cassette characterized in that it is 15 or less.