JPS6356480A - Ink ribbon cassette - Google Patents

Abstract

PURPOSE:To prevent defective take-up of an ink ribbon or runaway motions of the ribbon from occurring, by providing at least one of cassette cover plates with a projected part for making contact with a side part of the roll of the ink ribbon on a payout core, on the surface of the cover plate opposed to the ink ribbon. CONSTITUTION:At the beginning stage of take-up of an ink ribbon 7, a side part 7a of the roll of an ink ribbon makes contact with a projected part 6g, and a back tension is applied to the ink ribbon 7 due to a frictional force acting between the ink ribbon and the projected part 6g, so that the ribbon 7 is gradually taken up around a take-up core 9 without runaway motion. When the roll diameter of the ribbon on the payout core is reduced to or below l, the side part 7a of the roll of the ribbon does not make contact with the projected part 6g. At this time, however, an appropriate back tension is applied to the ribbon because of an increase in the take-up load, so that runaway motions of the ribbon do not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ink ribbon cassette used in a printing device that prints on a printing medium using ink using heat or pressure.

(Prior Art) Printing devices using cassette-type ink ribbons have recently become popular.

Figure 2 shows this type of conventional printing device (thermal blink)
In the figure, 1 is a platen, and 2 is a print head provided opposite the platen 1. Printing head 2
is a recording paper 4 supported by a presser roller 3 on a platen L.
It is mounted on a carriage 5 that moves in a direction (horizontal direction) perpendicular to the feeding direction (vertical direction). 6 is an ink ribbon cassette attached to the carriage 5, and this cassette 6
Inside, the ink ribbon 7 has its both ends hooked up between the original winding core 8 and the winding core 9, and is placed on both sides of the exposed part 6a for inserting the pad 2 into the printing provided on one side of the cassette 6. It is exposed to the outside through an exit 6b and a re-entrance 6c provided in the. The print head 2 fitted into the exposed part 6a of the cassette 6 is normally located away from the ink ribbon 7, but when it receives a print signal, it tilts toward the platen 1, presses the ink ribbon 7 onto the recording paper 4, and moves the carriage. 5, the heating element formed on the pressure bonding surface of the printing pad 2 generates heat while traveling in the lateral direction to perform printing.

In this type of device, in the early stage of winding the ink ribbon, the ink ribbon 7 tends to swing up and down, causing ribbon turbulence. When this ribbon turbulence occurs, it can cause missing characters and uneven print density. Print quality deteriorates.

Therefore, in order to prevent the ribbon from running wild, a conventional method has been adopted in which an appropriate pack tension (tension in the opposite direction to the running direction) is applied to the original winding core side of the ink ribbon. Back tension is applied by installing a coil spring, plate spring, etc. inside the ink ribbon cassette, and pressing the original winding core and the ink ribbon.

However, in such a conventional ink ribbon cassette, as the ink ribbon is wound up, a larger load is gradually applied to the winding core side. Therefore, there is a problem in that winding defects tend to occur in the latter stages of winding.

(Objects and Structure of the Invention) The present invention has been made in view of the above points, and an object of the present invention is to prevent the ribbon from rolling loosely without causing a winding failure of the ink ribbon. A protrusion is provided on the surface facing the ink ribbon to be in contact with the side of the ink ribbon wound around the original winding core.

(Example) The present invention will be explained below based on the drawings.

Figure 1 (a) is a partially cutaway plan view of an embodiment of an ink ribbon cassette with unreleased tl, and (b) is a sectional view taken along line A-A of (a), showing the same components as in Figure 2. are given the same reference numbers.

In the figure, 6d is a cassette bottom cover plate, 6e is a main winding shaft formed integrally with the cassette bottom cover plate 6d and into which the main winding core 8 is inserted, 6f is a cassette top cover plate, and 6g is a cassette top cover plate 6f.
This is a protrusion formed integrally with the cassette top cover plate 6f on the surface facing the ink ribbon 7. The protrusion 6g is the original winding core 8
The side portion 7a of the ink ribbon is in contact with the side portion 7a of the ink ribbon, which is further away than seen from the side portion 7a of the ink ribbon. The value of the radius is determined to be a value that does not cause the ribbon to run wild when the ribbon radius is less than this value.

Generally, ribbon unruliness occurs at the beginning of the ink ribbon winding, but it does not occur after the ink ribbon has been wound to a certain extent.This is because as the ink ribbon is wound, the ribbon radius on the source core side becomes smaller. This is because as the winding load increases, the back tension applied to the ink ribbon also increases accordingly.In this embodiment, when the ribbon radius on the winding core side is below the stationery, ribbon undulation does not occur.

Now, with the above configuration, in the initial stage of winding the ink ribbon 7, the side portion 7a of the ink ribbon is
comes into contact with the protrusion W66g. Its protrusion 6g
) 9! Since back tension is applied to the ink ribbon 7 by the frictional force, the ink ribbon 7 is wound around the winding core 9 without causing the ribbon to run wild.

Next, when the ribbon radius on the source core side is below the stationery, the side part 7a of the ink ribbon no longer comes into contact with the protrusion 6g (as shown by the chain line in FIG. 1(a)), but at this point the winding load is An appropriate amount of back tension is provided by the increase in , so that the ribbon does not run wild.

Further, the ink ribbon 7 is wound up.

The ribbon radius on the original winding core side becomes smaller, but because the original winding core side is not equipped with conventional pack tension members such as coil springs and leaf springs, an excessive winding load is applied. The ink ribbon 7 is wound up on the winding core 9 until the end.

As described above, according to this embodiment, the ink ribbon is wound without causing the ribbon to run wild in the early stage of winding, and without causing winding defects in the latter stage of winding. Since the protrusion is provided integrally with the cassette top cover plate, it is possible to provide a low-cost ink ribbon cassette with a small number of parts.

In the above embodiment, the protrusion was provided integrally with the cassette top cover plate; however, the present invention is not limited thereto, and the protrusion member may be attached to the cassette top cover plate, and the protrusion member may be a rigid body. If an elastic body (spring material, rubber material, foam material, etc.) is used, it is easy to make contact with the side part of the ink ribbon.

In the above embodiment, the protrusion 6g is provided on the cassette top cover plate 6f, because in this embodiment the ink ribbon cassette is loaded into the carriage with the cassette bottom cover plate 6d facing down. Therefore, when the ink ribbon cassette is loaded with the cassette top cover plate 6f facing down, the protrusion 6g may be provided on the cassette bottom cover plate 6d.
Further, when the ink ribbon cassette is loaded vertically, a protrusion 6g may be provided on one or both of the cassette cover plates.

Further, in the above embodiment, the protrusion is provided at a location more than an intersection away from the center of the original core, but the protrusion is not limited to this, and the protrusion may be provided from the outermost periphery of the ink ribbon to the center of the original core. Even in such a case, it is possible to prevent the ribbon from rolling wildly at the beginning of the 5th winding, and since the contact surface between the protrusion and the side of the ink ribbon becomes smaller as the ribbon is wound, the winding caused by this can be prevented. The winding load is also reduced, and problems such as poor winding in the latter stages of winding do not occur.

(Effects of the Invention) As explained above, in the present invention, at least one surface of the cassette lid plate facing the ink ribbon is provided with a protrusion that contacts the side of the ink ribbon wound around the original winding core. Therefore, it is possible to prevent the ribbon from running wild without causing a winding failure of the ink ribbon. Furthermore, according to the embodiment, since the protrusion is provided integrally with the cassette cover plate, it is possible to provide a low-cost ink ribbon cassette with a small number of parts.

[Brief explanation of the drawing]

FIG. 1(A) is a partially cutaway sectional view of an embodiment of the ink ribbon cassette according to the present invention, FIG. 1(B) is a sectional view taken along line A-A of FIG. FIG. DESCRIPTION OF SYMBOLS 1...Platen, 2...Print head, 5...Carriage, 6...Cassette, 6f...Cassette top cover plate, 6g...Protrusion, 7...Ink ribbon, 7a.・
・Ink ribbon side part, 8... Original winding core, 9... Winding core Patent applicant: Roku Konishi Photo Industry Co., Ltd. Agent Patent attorney: Hiroshi Suzuki (M) Figure 1 (A) t Figure 2 (R) 8 5

Claims (1)

[Claims] In an ink ribbon cassette in which an ink ribbon cassette wound around a source core is wound around a take-up core between two cassette cover plates, the source core is placed on at least one surface of the cassette cover plate facing the ink ribbon. An ink ribbon cassette characterized by being provided with a protrusion that comes into contact with a part of the ink ribbon wound on the ink ribbon.