JP2014193561A - Stencil printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stencil printer which can recover dust, adhering to stencil base paper, by a simple configuration, and which prevents defective perforation caused by a thermal head.SOLUTION: Characteristically, a stencil printer includes a stretch roller which is provided on an upstream side in a carrying direction of stencil base paper and which stretches the stencil base paper by coming into contact with a surface, on the opposite side of the side coming into contact with a thermal head, of the stencil base paper, and a dust removal member that comes into contact with a surface, on the side coming into contact with the thermal head, of the stencil base paper stretched by the stretch roller, in a position facing the stretch roller.

Description

The present invention relates to a stencil printing apparatus using a thermal head, and relates to a cleaning mechanism that removes dust accumulated in the thermal head.

The heat-sensitive stencil sheet used in the stencil printing device has a structure in which a very thin thermoplastic synthetic resin film such as polyester and a synthetic fiber or Japanese paper are bonded as a porous flexible support, On the film surface of the stencil paper, an overcoat layer composed of an antistatic agent such as a silicone release agent and a surfactant is usually formed to prevent welding with a heating element provided in a thermal head or the like. ing.

In the stencil printing apparatus, the film portion of this stencil sheet is heated and punched by a heating element such as a thermal head, the stencil sheet is conveyed and wound around the outer peripheral surface of a porous cylindrical plate cylinder, and a press roller is applied to the stencil sheet. The pressing means presses the printing paper continuously, and ink is oozed out from the opening portion provided in the plate cylinder and the punching portion of the base paper to perform printing.

In such a stencil printing apparatus, when the film portion of the stencil sheet is heated and punched by a heating element such as a thermal head, the dust adhering to the stencil sheet enters the heating element and its film, resulting in poor punching. Could occur. For this problem, various methods for preventing dust from adhering to the stencil sheet have been considered.

For example, the plate making apparatus of the stencil printing apparatus disclosed in Patent Document 1 discloses storage means including at least a master storage means and a lower cover that covers the plate making means and an upper cover that can be opened and closed with respect to the lower cover.

JP-A-6-293174

However, since the plate making apparatus of the stencil printing apparatus of Patent Document 1 is configured to cover the plate making apparatus itself with the upper cover and the lower cover, there is a problem that the apparatus becomes large. Even if the stencil sheet is covered with a cover, the stencil sheet is always in contact with air, so that dust in the air cannot be completely removed, and may adhere to the stencil sheet. Further, the dust mixed during the manufacture of the stencil sheet is not taken into consideration, and there is a possibility that the stencil sheet is made with the dust adhered.

If the stencil sheet is made with a thermal head in this state, the heat perforation becomes unstable due to dust adhering to the upper surface of the film at the time of manufacture, or dust adhering to the upper surface of the film while being left in the stencil printing device, resulting in image defects Problem still remains.

Accordingly, an object of the present invention is to provide a stencil printing apparatus in which dust does not enter between a thermal head and a stencil sheet during plate making using a thermal head.

  In order to achieve the above object, the first feature of the present invention is that a stencil sheet drawn from a base paper roll is heated and punched while being nipped and conveyed by a thermal head and a platen roller, and a predetermined length is obtained by a cutting member. In the stencil printing apparatus provided with a control unit that controls to create a stencil sheet that has been perforated by cutting, the side that is provided upstream of the stencil sheet in the transport direction and contacts the thermal head of the stencil sheet A tensioning roller that stretches the stencil sheet in contact with the opposite side of the stencil sheet, and a side of the stencil sheet that is stretched by the tensioning roller at a position facing the tensioning roller on the side that contacts the thermal head. A dust removing member in contact therewith.

The second feature of the present invention is that the dust removing member is provided so as to be able to contact with and separate from the stencil sheet, and the control unit cuts the dust removing member after being cut by the cutting member. The dust removing member is controlled to move to a position in contact with the stencil sheet after the stencil sheet is moved to a position away from the stencil sheet and conveyed reversely by a predetermined distance.

According to the first feature of the stencil printing apparatus of the present invention, since the dust removing member is in contact with the stencil sheet upstream of the thermal head in the stencil sheet transport direction, the dust adhering to the stencil sheet is being transported in the middle. Since the dust removing member collects and does not remain attached to the stencil sheet transported downstream from the dust removing member, poor perforation of the stencil sheet by the thermal head is prevented.

According to the second feature of the stencil printing apparatus of the present invention, after cutting by the cutting means, the dust removing member is separated, and the stencil sheet to which dust adheres therebetween is located upstream of the dust removing member in the stencil sheet conveying direction. Then, the dust removal member is moved again to a position where it comes into contact with the stencil sheet, so that dust adhering between the thermal head and the dust removal member can also be collected by the dust removal member. Therefore, the perforation failure of the stencil sheet by the thermal head is further prevented.

Schematic configuration diagram of a stencil printing apparatus in the present embodiment Control block configuration diagram of stencil printing apparatus in this embodiment Partial enlarged view of the plate making part of the stencil printing apparatus in this embodiment Timing chart related to the plate making operation of the stencil printing apparatus in this embodiment

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a stencil printing apparatus 1 according to an embodiment of the present invention.

[Overall configuration of stencil printing machine]
As shown in FIG. 1, the stencil printing apparatus 1 includes a document reading unit 10 that reads a document, a plate making unit 20 that performs a plate making process on the stencil sheet M based on image information read by the document reading unit 10, and a plate making unit 20. A printing unit 30 that prints on printing paper using the stencil sheet M that has been made, a paper feeding unit 40 that feeds the printing paper to the printing unit 30, a paper discharge unit 50 that discharges the printed printing paper, and a used stencil A plate discharging unit 60 to which the base paper M ′ is fed, a display unit 70 for displaying predetermined items and receiving input of predetermined printing conditions, and a control unit 80 for controlling each unit are provided. Note that the stencil printing apparatus 1 may be configured to directly receive image information from a personal computer or the like without including the original reading unit 10.

  The document reading unit 10 includes a document table 11 on which a document is placed, a pressing plate 12 that presses the document placed on the document table 11, a line image sensor 13 that photoelectrically reads image information of the document, and a line And a sensor transport unit 14 that transports the image sensor 13 in the sub-scanning direction (the direction of arrow A in FIG. 1). The sensor transport unit 14 includes a transport belt 14a to which the line image sensor 13 is attached, and a transport roller 14b that transports the transport belt 14a.

  The plate making unit 20 includes a base paper roll unit 21, a plate making unit 22 having a thermal head in which a plurality of heating elements are arranged in a row, a platen roller 23 that sends out the stencil sheet M fed from the base paper roll unit 21, and A base paper transport roller 24 for transporting the stencil sheet after the plate making, a transport motor 25 for driving the rotation of the platen roller 23 and the base paper transport roller 24, and the stencil paper M sent out by the platen roller 23 are cut to a predetermined length. A base paper cutter 26 is provided.

  The printing unit 30 is an ink-permeable cylindrical printing drum 31, a squeegee roller 32 disposed so as to be substantially inscribed in the printing drum 31, and a squeegee roller 32. A doctor roller 33 that forms an ink receiving portion R that extends in a direction perpendicular to the paper surface, an ink supply means 34 that supplies ink to the ink receiving portion R, and presses the paper P toward the printing drum 31. A press roller 35, an ink drive rod 36 disposed between the ink supply means 34 and the ink receiving portion R, and a print drum drive means 37 for rotating the print drum 31. A stencil sheet M is wound around the outer periphery of the printing drum 31. Ink from the ink supply means 34 is stored in the ink receiving portion R to form an ink reservoir AI.

  The paper feed unit 40 has a paper feed table 41 on which the print paper P is placed, and a primary paper feed roller 42 that takes out the print paper P one by one from the paper feed table 41 and sends it to the secondary paper feed roller 43. The leading end of the printing paper P that is disposed downstream of the primary paper feeding roller 42 in the carrying direction is temporarily stopped, and the printing paper P is pressed against the printing drum 31 at a predetermined timing. A secondary paper feed roller 43 is provided between the roller 35 and the roller 35.

  The paper discharge unit 50 peels off the printed printing paper P ′ from the printing drum 31, and the paper discharge tray described later on the printed printing paper P ′ peeled off from the printing drum 31 by the peeling claw 51. A paper discharge feeding belt unit 52 that conveys the printed printing paper P ′ conveyed by the paper discharge feeding belt unit 52 is provided.

  The plate discharging unit 60 is provided on one side of the printing unit 30 and pulls the used stencil sheet M ′ from the printing drum 31 and the plate discharging box 61 into which the used stencil sheet M ′ peeled off from the printing drum 31 is fed. A plate discharging roller 62 that peels off and feeds it into the plate discharging box 61 is provided.

  The display unit 70 is configured by a known display panel such as a liquid crystal panel or an LED panel. The display panel displays a message for prompting the operation state of the apparatus and replacement of the ink container, and also relates to a printing density such as a printing pressure at which the press roller 35 presses the printing drum 31 and a size of perforation at the time of plate making. The setting contents related to the setting contents and the printing speed (rotation speed of the printing drum) are displayed. In addition, the display unit 70 is configured to accept input by the operator regarding the setting contents regarding the print density and the printing speed, and to change these setting contents. The display unit 70 is configured to accept an input of a desired number of printed sheets and the number of printed copies by an operator and set them.

As shown in FIG. 2, the control unit 80 is connected to the document reading unit 10, the plate making unit 20, the printing unit 30, the paper feeding unit 40, the paper discharging unit 50, the plate discharging unit 60, and the display unit 70, and controls each unit. Each part is controlled by outputting a signal.

[Configuration of plate making section]
Next, the configuration of the plate making unit 20 will be described with reference to FIG. FIG. 3 is a partially enlarged view of the plate making unit of the stencil printing apparatus according to the present embodiment.

  The plate making unit 20 is provided with a stretching roller 27 between the base paper roll unit 21 and the plate making unit 22 for stretching the stencil paper M fed from the base paper roll unit 21. The tension roller 27 is positioned above the tangent line of the base paper roll unit 21 and the platen roller 23 in FIG. 3. When the stencil sheet M is conveyed by the platen roller 23, the tension roller 27 is placed on the surface of the tension roller 27. It will be stretched by contact.

  A dust removal brush 28 is provided at a position facing the tension roller 27. The dust removing brush 28 is provided with a brush portion 28 a at the tip of the dust removing brush main body 28 c, and the brush portion 28 a is in contact with the tension roller 27. The dust removing brush body 28c is provided so as to be rotatable about a shaft 28b. The shaft 28b is provided with a biasing means such as a coil spring (not shown). It is energized around.

  The dust removing brush 28 is normally biased by the tension roller 27 as shown in FIG. 3 by this biasing force. The dust D adhering to the surface of the stencil sheet M fed out from the base paper roll unit 21 is collected and prevented from reaching the thermal head 22.

  The thermal head 22 is fixed to the thermal head support member 235. The thermal head support member 235 is provided so as to be rotatable about the central axis 235a by the rotation of the plate making pressure adjusting cam 230 provided above the thermal head support member 235. By rotating the thermal head support member 235, the contact pressure between the thermal head 22 and the platen roller 23, that is, the pressure during plate making (plate making pressure) is adjusted. When the plate-making pressure adjusting cam 230 is located at the strong position, the plate-making pressure is strong. When the plate-making pressure adjusting cam 230 is located at the standard position, the plate-making pressure is standard, and when it is located at the weak position, the thermal head 22 and the platen. It will be in the separated state which does not contact with the roller 23, and the plate-making pressure will be released.

  Further, the tip 235b of the thermal head support member 235 is moved most clockwise when the plate making pressure adjusting cam 230 moves to the strong position, and comes into contact with the dust removing brush body 28c. As a result, the dust removal brush 28 rotates clockwise around the shaft 28 b against the urging force of the urging means, and the brush portion 28 a moves to a position away from the tension roller 27. . When the plate making pressure adjusting cam 230 is located at the standard position and the weak position, the dust removing brush 28 is in contact with the tension roller 27.

  In the present embodiment, the dust removal brush 28 is moved by the plate making pressure adjustment cam 230 via the thermal head support member 235, and the plate making pressure adjustment cam 230 also serves to drive the dust removal brush 28. However, a driving member may be provided separately.

[Effect of plate making part]
Next, the operation of the plate making unit 20 will be described with reference to FIG. FIG. 4 is a timing chart relating to the plate making operation of the stencil printing apparatus in the present embodiment.

  When a user makes a plate making start instruction from the display unit 70, the control unit 80 reads the document data by the document reading unit 10 and issues a plate making instruction to the plate making unit 20.

  The plate making unit 20 receives a plate making instruction, starts nipping and conveying the stencil sheet M by the thermal head 22 and the platen roller 23, and heat-pierces the stencil sheet M by each heating element of the thermal head 22 based on the document data (plate making operation). ). At this time, the plate-making pressure adjusting cam 230 is located at the standard position and applies a plate-making pressure necessary for heating drilling.

  Next, when the plate making operation by the thermal head 22 is completed and the stencil sheet M is conveyed by a predetermined distance by the platen roller 23, the stencil sheet cutter 26 is driven to cut the stencil sheet M into a predetermined length. The stencil sheet M cut to a predetermined length is supplied to the printing unit 30 separately.

  When the operation of the base paper cutter 26 is finished, the plate making pressure adjusting cam 230 moves to the strong position, and the thermal head support member 235 rotates clockwise in FIG. Then, the tip 235 b of the thermal head support member 235 comes into contact with the dust removal brush 28, and the dust removal brush 28 moves to a position away from the tension roller 27.

  At the same time, the platen roller 23 is driven in reverse and the stencil sheet M fed from the base paper roll unit 21 is conveyed in reverse while the plate making pressure is strong. At this time, since the base paper roll unit 21 is not driven, the stencil base paper M is held between the tension roller 27 and the base paper roll unit 21 so as to form a slack.

  When the platen roller 23 is transported in the reverse direction for T1 time, the driving of the platen roller 23 is stopped, the plate making pressure adjusting cam 230 is moved to the weak position, and the thermal head support member 235 is rotated counterclockwise. Then, the tip 235 b of the thermal head support member 235 moves away from the dust removing brush 28, and the dust removing brush 28 moves to a position where it abuts against the tension roller 27.

  Thereafter, the platen roller 23 is driven to rotate forward for the time T2 while the plate making pressure adjusting cam 230 is moved to the standard position, conveys the leading edge of the stencil sheet M to a predetermined position, and waits for the next plate making instruction. Become. At this time, since the dust removing brush 28 is in contact with the tension roller 27, the dust D can be collected.

  As described above, since the dust removing brush 28 is in contact with the tension roller 27 in normal times, the dust D adhering to the stencil sheet M fed from the base paper roll unit 21 reaches the thermal head 22. Therefore, it is possible to prevent a perforation failure caused by the thermal head 22.

Further, after the plate making operation is completed, the platen roller 23 is reversely conveyed, so that the dust D adhering to the platen roller 23 and the thermal head 22 can be rewound and collected by the dust removing brush 28. The perforation failure due to 22 can be prevented.

Further, when the platen roller 23 is transported in the reverse direction, since the plate making pressure between the thermal head 22 and the platen roller 23 is increased, dust D and the like adhering to the surface of the thermal head 22 can be scraped off. There is no need for separate cleaning.

Furthermore, since the operation for adjusting the plate making pressure and the operation for bringing the dust removal brush 28 into and out of contact with the tension roller 27 can be performed simultaneously by driving the plate making pressure adjusting cam 230, it is not necessary to provide a separate brush drive unit. And cost reduction can be realized.

DESCRIPTION OF SYMBOLS 1 Stencil printing apparatus 20 Plate making part 21 Base paper roll part 22 Plate making unit (thermal head)
23 Platen roller 26 Base paper cutter 27 Tension roller 28 Dust removal brush D Dust M Stencil paper

Claims (2)

A control unit that controls the stencil sheet drawn out from the stencil roll unit to be heated and punched while being nipped and conveyed by a thermal head and a platen roller, and cut to a predetermined length by a cutting member, thereby controlling the stencil sheet to be punched. In a stencil printing machine comprising:
A tensioning roller that is provided on the upstream side in the stencil sheet conveying direction with respect to the thermal head, and that stretches the stencil sheet in contact with the opposite side of the stencil sheet that contacts the thermal head;
A dust removing member that is in contact with the thermal head of the stencil sheet stretched by the tension roller at a position facing the tension roller;
A stencil printing apparatus comprising: The dust removing member is provided so as to be able to contact with and separate from the stencil sheet,
The controller is
After being cut by the cutting member, the dust removing member is moved to a position away from the stencil sheet,
2. The stencil printing apparatus according to claim 1, wherein the dust removing member is controlled to move to a position in contact with the stencil sheet after the stencil sheet is reversely conveyed by a predetermined distance. 3.