JPH09441U - Stencil printing machine - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an automated method at the time of starting a stencil printing machine. A stencil printing machine including at least a thermal head (3) for perforating a master (1), a platen roller (2) facing the thermal head (3), and a cutter (4) for cutting the master into a predetermined length, the tip of the master being gripped. Then, it is sandwiched between the platen roller and the thermal head, and after the sandwiching, the transport system of the stencil printing machine is driven to transport the master to the rear of the cutter, stop at that position, and operate the cutter to cut the master. Then, the stencil printing machine is configured to drive the transport system again to transport the master to a predetermined position, wait at that position, and perform initial setting.

Description

[Detailed description of the device]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a stencil printing machine having a thermal head.

[0002]

[Prior art]

 An elastic rubber roller is used as a platen roller in a stencil printing machine having a thermal head.

[0003]

[Problems to be solved by the device]

 In a stencil printing machine having a thermal head, there was a problem that the master surface was charged during plate making and transportation, resulting in poor transportation. In order to solve this problem, many proposals have been made to provide an antistatic layer on the surface of the master so that the master itself is less likely to be charged. However, in a low temperature and low humidity environment, the master's antistatic layer did not work sufficiently, and the problem of conveyance failure could not be solved. Under these conditions, if the resistance of the antistatic layer on the master is too low in order to suppress the generation of static electricity, the thermal head will be galvanically corroded and platemaking will become impossible. It was impossible.

FIG. 1 shows a plate making portion of a general stencil printing machine, and a roll-shaped master is mainly used as a master. To set the master, first set the master roll 1 at a predetermined position, and sandwich the tip of the master between the platen roller 2 and the thermal head 3. Next, when a master cut button (not shown) is pressed to align the tips of the masters, the driving force is transmitted to the platen roller 2 and the relay rollers 5 and 6 by the motors, etc., and the individual rollers rotate to reverse the masters. 7, the master is cut by the cutter unit 4, and then the master is again conveyed to a predetermined position (a position slightly beyond the relay roller 5) to complete the master setting. According to the master set method of the present invention, the master set operation can be automated, the work can be rationalized, and accurate positioning can always be performed. When a plate making start key (not shown) on the operation panel is pressed in this state, the platen roller 2, the relay rollers 5, 6 and the reversing rollers 7, 8 are rotated to convey the master to the master clamper 9. Here, the master clamper 9 is closed to sandwich the master, and the master is wound around the print drum. The master is cut by the cutter unit 4 after being conveyed for a predetermined length, and the tip is always stopped at a predetermined position (a position slightly out of the relay roller 5). At the same time when the master key is pressed to convey the master, the master, which transmits the image information of the original document to the thermal head 3, is punched to perform the master plate. The material of each roller is usually a rubber-like elastic body for the platen roller 2, a relay roller 5, 6 and a high hardness material such as a metal roller for the reversing rollers 7, 8 and an elastic roller. Used in Ra pair.

[0005] Here, a problem that is usually caused is a conveyance failure of the master due to static electricity. Particularly under low temperature and low humidity, the master is rubbed between the platen roller 2 and the thermal head 3, or between the relay rollers 5 and 6, and the reversing rollers 7 and 8, and the master, the relay roller 5, and the reversing roller Static electricity is generated on the roller 7. Here, static electricity generated between the platen roller 2 and the thermal head 3 is the biggest problem. In such a situation, an electrostatic force is generated between the master and the platen roller, and the master tip is rolled up on the platen roller and the master tip cannot be conveyed. In addition, when the master is set in the plate making part, the master may stick to the platen roller, which may cause a state in which the master cannot be set. This is because the platen roller generally has high resistance and is easily charged.

Therefore, the present invention solves the above-mentioned drawbacks and provides a stencil printing machine having a thermal head that does not cause a master transfer failure due to static electricity even in a low temperature and low humidity environment.

[0007]

[Means for Solving the Problems]

The above object is achieved by the present invention described below. That is, the platen roller is an elastic platen roller, and this platen roller has the property of releasing the electrostatic charge of the master, or the platen roller itself is treated so that it is hard to be charged by contact with the master. The problem can be solved by a stencil printing machine having a thermal head. When the surface specific resistance of the platen roller was 10 ⁹ Ω, a remarkable effect was observed, and no conveyance failure was observed even when the relative humidity was about 15%. Further, if it was 10 ⁷ Ω or less, no conveyance failure occurred even if the relative humidity was 10% or less.

In the platen roller of the present invention, the platen roller itself is not charged even if friction occurs with the master, and the charged charge of the master can be leaked. We were able to solve the problem of transport failure due to electrostatic air, such as being wrapped around the sheet and being unable to transport. Furthermore, when the master was set, the problem that the master stuck to the platen roller and could not be set could be solved. The surface resistivity was measured at 20 ° C. and 65%.

[0009]

【Example】

Example 1 A heat sensitive stencil printer was manufactured using a platen roller using a conductive silicone rubber having a surface resistivity of 8 × 10 ⁷ .

Example 2 A heat sensitive stencil printer using a platen roller using a conductive silicone rubber having a surface resistivity of 8 × 10 ⁹ was manufactured.

Comparative Example A heat-sensitive stencil printing machine using a platen roller using silicon rubber having a surface resistivity of 10 ¹⁴ was manufactured.

The performances of the platen rollers of Examples 1 and 2 and Comparative Example above are shown below. Operating environment (relative humidity) 20% 15% 10% 5% Example 1 ○ ○ ○ ○ 〃 2 ○ ○ △ × Comparative example △ × × × ○… Transfer failure / wrapping does not occur △… Transfer failure after continuous plate making・ May cause wrapping × ... Master cannot stick and set

[0013]

[Effect of the invention]

 As described above, according to the present invention, it is possible to provide a stencil printing machine having a stable thermal head that does not cause transfer failure or sticking of the master due to electrostatic discharge even in a very low humidity environment. .

[Brief description of drawings]

FIG. 1 is a view showing a plate making portion of a general stencil printing machine.

[Explanation of symbols]

 1 ... Master roll 2 ... Platen roller 3 ... Thermal head 4 ... Cutter unit 5 ... On relay roller 6 ... On relay roller 7 ... On reversing roller 8 ... On reversing roller 9 ... Master clamper 10 ... Drum 11-14 ... Guide plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Tateishi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (1)

[Utility model registration claims] 1. A stencil printing machine comprising at least a thermal head (3) for perforating a master (1), a platen roller (2) facing the thermal head, and a cutter (4) for cutting the master to a predetermined length. Grasp and pinch it between the platen roller and the thermal head, and after pinching, drive the transport system of the stencil printer to transport the master to the rear of the cutter, stop it at that position, and operate the cutter to operate the master. The stencil printing machine that cuts, drives the transport system again, transports the master to a predetermined position, waits at that position, and performs initial setting.