JPH0340619Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an ink ribbon cassette for a thermal printer.

[Prior art]

In a conventional ink ribbon cassette, as shown in FIGS. 5A and 5B, the ink ribbon 4 is wrapped around the original winding core 2 and the winding core 3 in the cassette body 1, and the ink ribbon 4 is placed in a recess 5 provided on one side of the cassette body 1. Guide rollers 6 and 7 are provided on both sides of the concave portion 5 to be exposed to the outside.
In addition, two tension rollers 8 and 9 are provided between the downstream guide roller 7 and the winding core 3.
has been established. Therefore, when the amount of winding of the ink ribbon 4 on the winding core 3 is small, the angle θ between the tension roller 9 on the downstream side and the winding core 3 becomes an acute angle as shown in FIG. As the amount of winding of the winding core 3 increases, the angle gradually becomes obtuse as shown in FIG. For this reason, since the tension of the ink ribbon changes when it runs, the ink ribbon wound around the take-up core may wind unevenly, and the relative speed between the ink ribbon and the recording paper cannot be maintained at 0''. The ink ribbon sometimes rubbed against the recording paper and stained the recording paper, causing a reduction in print quality.

[Purpose of invention]

This invention is intended to solve the above problem, and aims to provide an ink ribbon cassette in which the winding tension is always constant regardless of the amount of ink ribbon wound around the winding core. .

[Structure of the idea]

In order to achieve the above object, this invention is designed to expose the ink ribbon, which is stretched between the original winding core and the take-up core in the cassette body, to the outside through a recess on one side of the cassette main body. In an ink ribbon cassette in which a guide roller is provided, a sliding member is pivotally supported at a portion corresponding to the apex of an isosceles triangle whose base is between the axes of the guide roller, and has one end in sliding contact with the back surface of the ink ribbon on the original winding side. The contact member is rotatably provided with a rotary spring plate each having an insertion member at the other end through which the ink ribbon on the winding side is inserted.

〔Example〕

Next, this invention will be explained based on the embodiments shown in FIGS. 1 to 4.

In the figure, reference numeral 10 denotes a flat box-shaped cassette body containing an ink ribbon a;
0 is a carriage 2 equipped with a thermal head 20
It is designed to be attached by fitting the recesses 11, 11' at the center of the front and rear surfaces into the locking protrusions 22, 22' on the front and rear surfaces. The ink ribbon a has a source core 12 and a take-up core 13 in the cassette body 10.
Both ends are wound around the recess 11 on the front edge side and exposed to the outside via guide rollers 14 and 15 provided on both sides thereof. The thermal head 20 is fitted between the recess 11 and the exposed portion of the ink ribbon a, and its tilting presses the ink ribbon a onto recording paper (not shown) to print. .

Reference numeral 16 denotes a rotating spring plate supported by a shaft 17 erected at a portion P corresponding to the apex of an isosceles triangle (indicated by a two-dot chain line) whose base is between the axes of the guide rollers 14 and 15; The rotating spring plate 16 is provided at one end with a sliding member 18 that slides into contact with the back surface of the ink ribbon a on the source side, and at the other end is provided with an insertion member through which the ink ribbon a on the take-up side is inserted. 19 are provided. The rotating spring plate 16 is made of an elastic material such as resin or metal and is formed into an arcuate shape. As shown in FIG. 3B, the sliding contact member 18 is formed into a block shape of a slippery material such as felt or Teflon impregnated with silicone oil. Also,
The insertion member 19 is formed to have a U-shaped cross section as shown in FIG.

In the figure, reference numeral 23 denotes a winding shaft protruding above the carriage 21 so as to fit into the winding core 13 in the cassette main body 10;
When the motor is moored to a timing belt 31 driven by a drive motor 30 and travels along a guide shaft 32, a drive gear rotates in conjunction with a rack 33, a pinion 34, and an intermediate gear 35 arranged in parallel on the travel path. Provided integrally with 36 shafts,
The thermal head 20 rotates in the winding direction only when performing a printing operation.

In the above embodiment, when the cassette main body 10 is set on the carriage 21, the ink ribbon a
Since the original winding core 12 is fully wound, the rotary spring plate 16 is at its maximum tilt downward to the left as shown in FIG. 4A, but as the printing operation progresses, the winding shaft 23 The take-up core 13 is rotated to take up the ink ribbon a, and as the take-up diameter gradually increases, the inclination angle decreases, and when the winding amounts of the original winding and the winding core become equal (at the point 1), the inclination is downward to the right, and when the ink ribbon a of the original core 12 is finished, the inclination is maximum downward to the right as shown in FIG. 4B. That is, the ink ribbon has the rotating spring plate 1 attached to its original winding core from the time of full winding to the end of winding.
Due to the slope of 6, the same tension is always applied.

[Effect of idea]

As described above, this invention has guide rollers on both sides of the recess in order to expose the ink ribbon stretched between the source core and take-up core in the cassette main body through the recess in one side of the cassette main body. In the provided ink ribbon cassette, a sliding member is rotatably supported at a portion corresponding to the apex of an isosceles triangle whose base is between the axes of the guide rollers, and has a sliding contact member at one end that is in sliding contact with the back surface of the ink ribbon on the original roll side. , the rotational spring plate is rotatably provided with an insertion member at the other end through which the ink ribbon on the winding side is inserted, so that the tension during winding of the ink ribbon is controlled by the rotational spring plate. Due to this effect, the winding amount is always the same regardless of the winding amount of the winding core. Therefore, as long as the ink ribbon is not wound unevenly due to tension unevenness when it is wound around the take-up core, and the relative speed between the ink ribbon and the recording paper is set to 0''. , the relative speed will not go out of order after that,
This has the excellent effect that the ink ribbon does not rub against the recording paper and a high quality printing surface can be obtained.

[Brief explanation of drawings]

1 to 4 show an embodiment of this invention, in which FIG. 1 is a plan sectional view of the cassette body,
The figure is a perspective view showing the state before the cassette body is attached to the carriage, Figures 3A and B are enlarged perspective views of the ends of the rotating spring plate, and Figures 4A and B are views showing the action of the rotating spring plate. FIGS. 5A and 5B are plan sectional views explaining the operation of the conventional example. 10...Cassette body, 12...Main volume core, 1
3... Winding core, 14, 15... Guide roller,
16... Rotating spring plate, 18... Sliding member, 19...
...insertion member, a...ink ribbon.

Claims (1)

[Scope of utility model registration request] In an ink ribbon cassette in which guide rollers are provided on both sides of a recess in one side of the cassette main body to expose the ink ribbon stretched between a source core and a take-up core in the cassette main body to the outside from the recess in the one side of the cassette main body. , a sliding contact member is supported at one end corresponding to the apex of an isosceles triangle whose base is between the axes of the guide rollers, and is in sliding contact with the back surface of the ink ribbon on the source winding side at one end, and a sliding member at the other end on the winding side. An ink ribbon cassette, characterized in that it is rotatably provided with rotatable spring plates each having an insertion member through which the ink ribbon is inserted.