JPS59194880A - Back tension generator for ink ribbon - Google Patents

Abstract

PURPOSE:To make constant a back tension irrespective of variations in the residual amount of an ink ribbon and without requiring any fitting operation for the ink ribbon, by a method wherein the shaft of an ink ribbon drawing-back wheel is connected through a spiral spring to a sliding wheel against which a friction member is pressed by a spring. CONSTITUTION:The shaft 24 of the ink ribbon drawing-back wheel 22 against which a rotary wheel is pressed is connected through the spiral spring 17 to the sliding wheel 18 against which the friction member 19 is elastically pressed by the spring 15. When the ink ribbon is drawn out, the sheel 22 is rotated, the rotation of the shaft 24 is transmitted by a rotation-transmitting plate 16, and the spring 17 is wound up. Therefore, when the ink ribbon is sagged, a recoil force of the spring 17 is transmitted, the wheel 22 is rotated in the opposite direction, and the sag of the ribbon is absorbed. As a result, the back tension on the ink ribbon remains constant irrespectively of the residual amount of the ink ribbon. In addition, there is no tension roller or the like, and fitting of the ink ribbon or the like is unnecessitated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to impact type printers that use an ink ribbon and print characters by mechanically moving the ink ribbon, or thermal transfer printers that print using thermal means. This invention relates to a back tension generating device for an ink ribbon.

Structure of the conventional example and its problems Figure 1 shows the vicinity of the ink ribbon supply section of a conventional printer. 4).[!!Ik roller (4)
The position of the tension roller (3) is fixed, but the tension roller (3) is attached to a tension arm (6) that rotates around the axis (5) of the supply ink ribbon reel (1), and the tension arm spring (7 From this state, when the ink ribbon (illustration) is pulled out in the direction of arrow B, the friction of the shaft (5) is set to be large, so the tension arm (7) The extension tension arm (6) rotates in the direction of arrow C.

That is, the tension roller (3) comes to the 1st N: position indicated by the dotted chain line. If an attempt is made to pull out the ink ribbon (2) any further, the shaft (5) rotates over four strokes and the ink ribbon (2) is pulled out. Ink ribbon (2
) is the back tension of the tension arm (7).
) is generated due to the tensile force of To obtain such a configuration, the ink ribbon (2) must be hung on a tension roller (3) and a rotating roller (4).

Also, since the tension roller (3) needs to be moved,
The equipment was also getting bigger. In order to solve these problems, devices as shown in FIGS. 2 and 8 can be considered. In FIGS. 2 and 8, the ink ribbon is wound around the supply ink ribbon reel on the upper substrate (2), and the reel (2) is fitted onto the reel shaft C141. A rotation transmission plate C1l on the lower substrate (G) is combined with the lower part of the reel axis α◆. Here, a square hole is formed in each of the reel hole and the rotation transmission plate Q, and is adapted to fit with the reel shaft α4. Rotation transmission plate (II
A spiral spring ση is provided on the outside of the spiral spring ση, and one end of the spring α force is connected to the rotation transmitting plate α, and the other end is connected to the slide wheel. Further, on the outside of the sliding wheel (G), a friction arm 4 holding a friction material a1 is pivotally supported on the lower substrate OQ with a shaft (20a), and the friction arm 4 is attached to the sliding wheel (G) by a coil spring e. C) It is pushed to the side. The back tension is generated because when the ink ribbon 0υ is pulled out, the reel shaft α rotates in the direction of the arrow in FIG. 8, and this rotation is stored in the swirl aη. When the spiral spring αη is pulled out to a certain extent, it winds around the rotation transmission plate Of9. Then the reel axis σ◆
The rotation of is transmitted to the sliding wheel (G), and when the rotational force overcomes the frictional force generated between the friction material α, the sliding wheel (G)
rotates. That is, the ink ribbon Qυ is pulled out. As described above, the apparatus shown in FIGS. 2 and 8 has the advantage of being able to be configured very small, but since the back tension generated by this apparatus is of a constant rotational moment, it is possible to prevent the ink ribbon from remaining. There was a drawback that the tension value generated in the ink ribbon itself varied depending on the winding diameter of the ink ribbon.

Purpose of the Invention The present invention has been made to address the above-mentioned conventional problems.
The work of hanging the ink ribbon fet, r<shi.

Another object of the present invention is to provide an ink ribbon tension generating device that maintains a constant tension value even if the remaining amount of the ink ribbon changes.

Structure of the Invention In order to achieve the above object, the ink ribbon back tension generating device of the present invention is provided with a pull-back wheel at an ink ribbon outlet in a printing device.

The shaft of this pull-back wheel is connected via a spiral spring to a sliding wheel against which the roofing material is pressed by a spring.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, a first embodiment will be explained based on FIGS. 4 to 6.

The device of this first embodiment is almost the same as the conventional example shown in FIGS. 2 and 8, and the difference is that in the conventional example, a rotational moment that generates back tension acts on the reel axis, but in this example, In the apparatus of the invention, the pull-back wheel (a) at the outlet of the supplied ink ribbon acts. In the figure, the ink ribbon east is wrapped around the outer periphery of the pull-back wheel 4, and the crimping rotary wheel (2) has a spring (not shown) that presses the crimping rotary wheel 4 in the direction of the pull-back wheel (A). It suppresses συ. In the drawings, the same reference numerals as those shown in FIGS. 2 and 8 indicate the same members, and detailed explanation thereof will be omitted. The mechanism of back tension generation is as follows.

When trying to pull out the ink ribbon αp wound on the reel μs, the pull-back force (A) rotates in the direction of arrow E in FIG. Then, this rotation is transmitted to the pull-back force 1llI□□□1 rotation transmission plate aQ, and winds the spiral spring αη.

After this state is reached, when the ink ribbon (b) is bent due to movement of the print head (not shown), the restoring force of the spiral spring is transmitted to the pullback J@(a).

The pullback wheel (support) rotates in the opposite direction to arrow E in FIG. Then, the deflection of the ink ribbon 0υ will be absorbed. Further, the pack tension value at this time has no relation to the remaining amount of the ink ribbon 0υ wound on the reel Q3, and the pack tension value does not change between the beginning and end of supply of the ink ribbon aυ.

FIGS. 7 and 8 show a second embodiment, which eliminates the parts on the left side of the pull-back arm of the first embodiment. That is, the rotation of the pullback wheel (A) is transmitted from the pullback gear (A) to the toothed part of the back tension shaft (A) via the intermediate gear (E), and the above-mentioned spiral spring α force is applied to this back tension shaft. A friction arm (4) with a sliding wheel (c) and a friction material part.

A pack tension generating means composed of a coil spring Cv is combined. In the first embodiment, the parts protruded considerably to the left side of the pull-back wheel (A), but in the second embodiment, these parts can be moved under the pull-back wheel (A) and under the ink ribbon reel. Therefore, effective use of space can be measured.

FIG. 9 and FIG. 1θ show the eighth embodiment, and in FIG. 1, () is a rotary arm that can rotate once around the arm axis (). An intermediate gear shaft 0◇ and a retraction axle ■ are pivotally supported on the rotating arm quadruple; ) are provided for each. Further, the back tension shaft is rotatable around the rotary arm shaft (7).

A rotating arm spring is connected to the rotating arm 4, and the pull-back force acts to constantly press the ink ribbon reel periphery above the reel. This rotating arm spring (
Due to the action of (a), when the remaining amount of the ink ribbon cI◇ becomes small, the pullback wheel (a) comes to the position indicated by the 9th N: dotted chain line. The mechanism for generating back tension on the ink ribbon (b) is the same as in the second embodiment. The third above
The advantage of the embodiment is the above-mentioned 1. In the second embodiment, the crimping rotary wheel (2) is required, whereas the plowing can be done by oneself, which means that the number of parts can be reduced.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

l) Conventionally, since the tension value of the ink ribbon itself fluctuates slightly due to changes in the remaining amount of the ink ribbon, it is necessary to set the force for winding up the used ink ribbon at the highest pack tension value.

It was necessary to increase the winding force, but in the present invention, the pack tension value does not change depending on the remaining amount of ink ribbon, so by setting the pack tension value to the minimum necessary value, the winding force can be reduced compared to the conventional method. Can be made smaller.

2) Since a spiral spring is used, the amount of displacement of the spring can be increased, and even when the ink ribbon is deflected to a large degree, the pack tension value can be kept less fluctuated.

8) There is no need to hang the ink ribbon.

Moreover, it can be stored in a relatively small space.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a first conventional example, FIGS. 2 and 8 are longitudinal sectional views and back views showing a second conventional example, and FIGS. 4 to 6 are a first embodiment of the present invention. Give an example. Figure 4 is a plan view, Figure 5 is a vertical sectional view, Figure 6 is a back view,
7 and 8 are a vertical sectional view and a back view showing a second embodiment of the invention, and FIGS. 9 and 10 are a plan view and a vertical sectional view showing a third embodiment of the invention. 0℃...Ink ribbon, 03...Ink ribbon reel. a4...Reel shaft, cIQ...Rotation transmission plate, α force...Spiral spring, (to)...Sliding wheel, CI...
・Friction material, (E)...Friction arm, e])...Coil spring, (2)...Retraction wheel, (C)...Crimping rotary wheel. (Foundation)...Retraction axle, (C) -...Retraction gear, (
e)...Intermediate gear. (A)...Pack tension shaft, (E)...Gear,
翰...rotating arm, ni)...rotating arm axis, 6υ・
...Intermediate gear shaft, etc.)...Rotating arm spring agent Yoshihiro Morimoto Figure 1 Figure 2 Figure 4 Figure 7 Figure 1 Figure β Figure q

Claims (1)

[Claims] 1. In the printing ha, a pull-back wheel is provided at the outlet of the ink ribbon, and the shaft of the pull-back wheel is connected via a spiral spring to a slide wheel to which a friction material is pressed by a spring. Back tension generator. 2. The ink ribbon back tension generating device according to claim 1, wherein a sliding wheel and a spiral spring are arranged coaxially with the axis of the retracting wheel. 8. Claim 1, in which a slide wheel and a spiral spring are provided on a shaft different from the shaft of the pull-back wheel, and the shaft supporting the spiral spring and the shaft of the pull-back wheel are interlocked and connected via gears. 2. The ink ribbon back tension generating device described in 2. 4. The ink ribbon back tension generating device according to claim 1, wherein the pull-back wheel is brought into pressure contact with the outer periphery of the ink ribbon on the supply ink ribbon reel and is movable according to the remaining diameter of the ink ribbon.