JPH0333478Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field This invention is applicable to an ink sheet cassette used in a recording device such as a line printer using a thermal head or the like, particularly an ink sheet cassette having a supply roll shaft and a take-up roll shaft. , relates to a back tension mechanism that applies back tension to an ink sheet on the supply side in order to tension the ink sheet and remove slack from the ink sheet.

Prior Art In order to reduce the storage space for the ink sheet cassette and to prevent the intrusion of dust, etc., the applicant separated the cassette body into a supply side case and a take-up side case, and connected them with an extendable connecting member. We have already proposed a system in which a back tension mechanism is installed inside the supply case, and have previously filed a patent application (Japanese Patent Application No. 60-6797). FIGS. 4 and 5 schematically show the supply side case 1 and the winding side case 2. The supply side case 1 and the winding side case 2 are connected at both outer left and right ends by a connecting member (not shown) which is extendable and retractable. Inside the supply side case 1, there is a supply side shaft 4 that supports the ink sheet roll 3, and inside the winding side case 2, there is a winding side shaft 6 for winding up the ink sheet 5. supported. An ink sheet outlet 7 is formed in the supply side case 1, and an ink sheet inlet 8 is formed in the winding side case 2, and a static elimination brush 9 is attached to each of these openings.

On the supply side axis 4, there is a tension arm 1 consisting of a rod portion 10a and arm portions 10b at both left and right ends of the rod portion 10a.
0 is rotatably supported. This tension arm 10 is connected to a spring 12 via a wire 11 that is wound around the shaft core 4, and is biased in the direction of the arrow in FIG. 4 to apply back tension to the ink sheet 5 by means of a rod portion 10a.

However, in this case, tension arm 1
Since the rod part 10a of 0 and the left and right arm parts 10b are integrated, or the left and right arm parts 10b are fixed to both ends of the rod part 10a, and the axis 4 is constructed as a whole, the left and right arm parts 10b are Since the distance is shorter than the length of the shaft 4, it is necessary to attach the tension arm 10 to the shaft 4 with a space between the left and right arm portions 10b. There was a problem that the arm 10 did not operate properly.

Japanese Unexamined Patent Publication No. 59-230941 discloses a configuration in which the rod portion of a tension arm and the left and right arm portions can be separated. However, in the case of this thigh, when attaching the arm to the rod,
Similarly, there was a problem in that the tension arm did not operate normally due to a deviation in parallelism between the rod portion and the axis.

Purpose The purpose of this invention is to solve such problems and
The objective is to ensure the normal operation of the tension arm, prevent the occurrence of wrinkles on the ink sheet, obtain good images, and facilitate the attachment of the tension arm to the axis. .

Configuration In order to achieve this objective, the present invention includes a rod portion 3, as shown in the illustrated embodiment below, for example.
3, 40, 43 and arm portions 34a, 34 at both ends thereof
b, 41a, 41b, 45a, 45b is rotatably supported on the axis 35 of the ink sheet roll 20 on the supply side. In the back tension mechanism of the ink sheet cassette that applies tension, the shaft core 35 is divided into a core tube 36 and a head that fits into both ends of the core tube 36, and the arm portions 3 at both ends of the rod portions 33, 40, 43
4a, 34b, 41a, 41b, 45a, 45b
The length between them is approximately the same as the length of the core tube 36 in the axial direction.

Hereinafter, embodiments of this invention will be described based on the drawings.

FIG. 1 shows an embodiment of this invention, in which the supply side shaft core 35 supporting the ink sheet roll 20 is
Although not shown, it is rotatably supported within the supply side case of the ink sheet cassette, similar to those shown in FIGS. 4 and 5. The tension arm 32 has a rod portion 33 and left and right arm portions 34.
a, 34b are provided integrally, but the shaft center 35
consists of a core tube 36 long enough to fit between the left and right arms 34a, 34b, and left and right heads 37a, 37b. That is, the axis 35 connects the small diameter portions 38 of the left and right heads 37a, 37b to the left and right arm portions 34.
It is assembled by press-fitting it into both ends of the core tube 36 through the bearing holes 39 of a and 34b, and at the same time, the tension arm 32 is attached to the left and right heads 3.
It is rotatably supported by 7a and 37b. The tension arm 32 is biased in a predetermined direction by a coil spring 30 that is wound around one end of the shaft core 35.
The rod portion 33 applies back tension to the ink sheet.

The tension arm includes a rod portion 40 and left and right arm portions 41a, 41 as shown in FIG.
b and C-shaped left and right bearing portions 42a, 4 at their tips.
2b are integrally provided with a flexible wire material such as a wire, and the left and right arm portions 41a, 41b have spring properties, or as shown in FIG. 3, the rod portion 43
and left and right arm portions 45 each having a bearing hole 44.
a, 45b may be integrally provided with synthetic resin, and the rod portion 43 may have rigidity, and the left and right arm portions 45a, 45b may have spring properties.

Effects According to this invention, the tension arm can be pivoted around the axis without deforming the arm portions at both ends of the tension arm, so stable operation can be ensured, and wrinkles on the ink sheet can be avoided. can be prevented and good images can be obtained. Furthermore, attachment of the tension arm to the shaft center becomes easy.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing one embodiment of this invention, and FIGS. 2 and 3 are perspective views showing other examples of the tension arm. FIGS. 4 and 5 are cross-sectional views showing conventional examples. 20... Ink sheet roll, 32... Tension arm, 33... Rod portion, 34a, 34b
...Left and right arms, 35... Axis core, 36... Core tube,
37a, 37b... Left and right heads, 40... Rod portion, 41a, 41b... Left and right arm portions, 43...
Rod parts, 45a, 45b... left and right arm parts.

Claims (1)

[Scope of utility model registration request] A tension arm consisting of a rod part and arm parts at both ends is rotatably supported on the axis of the ink sheet roll on the supply side, and the tension arm applies back tension to the ink sheet. In the back tension mechanism of the seat cassette, the shaft core is divided into a core tube and a head that fits into both ends of the core tube, and the length between the arms at both ends of the rod portion is equal to the length of the core tube in the axial direction. A back tension mechanism for an ink sheet cassette, which is substantially the same as the back tension mechanism of an ink sheet cassette.