JPH089097Y2 - Roll paper curl removal mechanism - Google Patents

Description

[Detailed Description of the Invention] [Outline] The present invention is a mechanism for removing a curl by bending a roll paper in the direction opposite to the curl, and for a portion having a large winding diameter and a weak curl, bending in the opposite direction. It is intended to provide a mechanism for uniformly removing the curl of roll paper by increasing the bending angle for bending a portion having a small angle, a small winding diameter, and a strong curl in the opposite direction.

[Industrial application field]

The present invention relates to a small thermal printer used as an output device of various electronic devices, and more particularly to a mechanism for removing the curl of roll paper.

2. Description of the Related Art A small thermal printer that presses a thermal head against a platen to feed a print sheet to a portion where the two are in contact with each other for printing generally uses a sheet (referred to as a roll sheet) wound in a cylindrical shape as the print sheet.

However, if the roll paper has a curl and characters or symbols are printed and pushed out of the device, the curl will immediately curl into a cylindrical shape. There is a problem that you have to spread it out with.

Therefore, a mechanism for removing the curl of the roll paper is added to the apparatus, but the curl of the roll paper is weak at the portion where the roll diameter is large and becomes stronger as the roll diameter approaches the inner peripheral portion and the roll diameter becomes smaller. Therefore, the curl removal mechanism that applies a uniform force regardless of the roll diameter of the roll paper applies the curl in the opposite direction to the roll paper in the weak curl and removes the curl in the strong curl. I can't do it. Therefore, in order to uniformly remove the curl, it is desirable that the force applied can be adjusted according to the roll diameter of the roll paper.

[Conventional technology]

FIG. 2 is a schematic sectional view showing an example of a conventional roll paper curl removing mechanism.

In the figure, as a mechanism for removing the curl of the roll paper 2 wound around the roll paper support shaft 1, a plate or a shaft 3 is fixed to a frame body of an apparatus (not shown). The roll paper 2 that has passed through while rubbing against the side surface and further rubbing against the guide portion 4 of the frame body of the apparatus is bent by the plate or the shaft 3 in the direction opposite to the curl, and the curl is weakened. The larger the angle θ bent by the plate or shaft 3 and the guide portion 4 of the frame is, the larger the force acting to remove the curl of the roll paper 2 can be.

[Problems to be solved by the invention]

However, in the roll paper curl removing mechanism, the bending angle θ ₁ is large and the force for removing the curl of the roll paper 2 is strong in the portion where the roll diameter is large and the curl is small. There is a problem that the bending angle θ ₂ becomes small in the strong portion, and the force acting to remove the curl of the roll paper 2 becomes weak.

[Means for solving problems]

FIG. 1 is a perspective view showing a roll paper curl removing mechanism of the present invention. Note that the same object is denoted by the same symbol throughout the drawings.

The above-mentioned problem is that the pressing shaft 51 for contacting the cylindrical surface of the roll 22 formed by winding the belt-shaped paper 21 shown in FIG.
A pair of support arms 52, one end of which is rotatably pivoted to the frame and the other end of which is fitted and inserted into the end of a shaft 51, and one end of which is rotatably pivoted to the frame and the other end side face is restrained. A pair of tension coil springs 61 having a pair of holding arms 62 that abut against the end of the shaft 51 and biasing the holding shaft 51 against the roll 22 are provided between the middle of the holding arms 62 and the frame body. This is solved by the roll paper curl removing mechanism of the present invention mounted on the.

[Action]

In FIG. 1, the pressing shaft 51 is constantly pressed against the cylindrical surface of the roll 22 by a tension coil spring 61 regardless of the diameter of the roll 22, and the pressing shaft 51 rubs against the side surface of the pressing shaft 51 and further guides the guide portion 4 of the device frame. Roll paper that passed while rubbing against each other
21 is bent in the direction opposite to the curl by the restraining shaft 51 and the guide portion 4, and the curl is weakened.

The roll 22 has a large diameter and a weak curl, and the angle bent by the restraining shaft 51 and the guide portion 4 is small.
As the diameter of becomes smaller and the winding tendency becomes stronger, the pressing shaft 51
The angle bent by the guide portion 4 becomes large.

That is, the bending angle is small in the portion with a weak curl and the force acting to remove the curl of the roll paper 21 is weak, while the bending angle is large in the portion with a strong curl and acts to remove the curl of the roll paper 21. The power to do it becomes stronger. Therefore, it is possible to realize a roll paper curl removal mechanism that uniformly removes curl by adjusting the force applied according to the roll diameter of the roll paper.

〔Example〕

 An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, the roll paper curl removing mechanism is a roll formed by winding the roll paper 21 into a cylindrical shape as a mechanism for removing the curl of the roll paper 21 wound around the roll paper support shaft 1.
The pressing shaft 51 that abuts against the cylindrical surface of 22 and one end of which is rotatably fixed to the frame body 7 (only one side is shown to explain the inside) by the shaft 53 and the other end of which is the pressing shaft 51. Support arm to support
52 and a tension coil spring 61, one end of which is rotatably fixed to the frame body 7 by a shaft 63 and the other end side surface thereof abuts on the restraining shaft 51, and one end of which is hooked on a pin 64 and the other end of which is hooked on the frame body 61. And hold down axis
A restraining arm biased in the direction of pressing 51 against the roll 22
62 and. The distance from the position of the restraining arm 62, which comes into contact with the restraining shaft 51, to the center of the shaft 63, which is secured to the frame body 7, is
The roll 22 is configured to be long in a large diameter portion and short in a small diameter portion of the roll 22, so that the biasing force of the tension coil spring 61 applied to the restraining shaft 51 is increased in a large diameter portion of the roll 22. It weakens and increases as the diameter of roll 22 decreases.

In such a roll paper curl removing mechanism, the bending angle becomes smaller and the biasing force of the tension coil spring 61 acting on the roll paper becomes weaker in a portion where the roll 22 has a large diameter and the curl is weak. The force acting to remove the curl of the paper 21 becomes weaker. On the contrary, in the portion where the diameter of the roll 22 is small and the winding tendency is strong, the bending angle becomes large and the biasing force of the tension coil spring 61 acting on the roll sheet becomes strong. The force acting on the removal becomes stronger. Therefore, it is possible to realize a roll paper curl removal mechanism that uniformly removes curl by adjusting the force applied according to the roll diameter of the roll paper.

[Effect of device]

As described above, according to the present invention, it is possible to provide a roll paper curl removing mechanism that uniformly removes curl by adjusting the force applied according to the roll diameter of the roll paper.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a schematic sectional view showing a conventional example. In the figure, 1 is a roll paper support shaft, 4 is a guide part, 7 is a frame, 21 is roll paper, 22 is roll, 51 is a holding shaft, 52 is a support arm, 53, 63
Is a shaft, 64 is a pin, 61 is a tension coil spring, and 62 is a holding arm.

Claims (1)

[Scope of utility model registration request] 1. A holding shaft (51) for contacting a cylindrical surface of a roll (22) formed by winding a belt-shaped paper (21) in a cylindrical shape, and one end rotatably fixed to a frame body. A pair of support arms (52) whose other ends are fitted and inserted into the ends of the holding shaft (51), and one end of which is rotatably fixed to the frame body and whose other end side surface is the end of the holding shaft (51). And a pair of restraining arms (62) that come into contact with the section, and the restraining shaft (51)
A pair of tension coil springs (61) for urging the roller in the direction of pressing the roll (22) are mounted between the middle of the restraining arm (62) and the frame body. Removal mechanism.