JP2002264459A - Stencil printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the size of a plate cylinder and to reduce a noise or a vibration due to a printing operation. SOLUTION: A stencil printer comprises the plate cylinder 24 rotatable around an axis (central axis 27) of itself by forming an ink passable peripheral wall 26 in a cylindrical shape. In this printer, a charge is imparted to the outer peripheral surface of the plate 24, and stencil paper M is attracted to and held on the peripheral surface of the plate 24 by this charge. Thus, a clamping mechanism or the like for holding the distal end of the paper M is eliminated. The outer peripheral area of the cylinder 24 is reduced, and hence the cylinder can be reduced in size. Since a movement of avoiding a collision of a press roller 33 with the clamping mechanism or the like can be dispensed at a printing time, the noise or the vibration due to the printing operation can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing apparatus for printing on printing paper by rotating a cylindrical plate cylinder around which a stencil sheet is wound. The present invention relates to a stencil printing apparatus to be mounted.

[0002]

2. Description of the Related Art Generally, a stencil printing apparatus is provided with a cylindrical plate cylinder which is driven by rotating a stencil sheet on the outer peripheral surface thereof. Then, with the rotation of the plate cylinder, the ink supplied to the inside of the plate cylinder is supplied to the stencil sheet on the outer peripheral surface of the plate cylinder, and the ink that has passed through the perforated portion of the stencil sheet is transferred to the printing paper to perform printing one after another. .

FIG. 3 is a side view showing a conventional stencil printing apparatus. As shown in FIG. 3, the plate cylinder 80 has a plate mounting seat 8 along an outer peripheral ridge line and an axis of rotation of the plate cylinder 80.
1 is provided. The plate mounting seat 81 is provided with a magnet plate 82. A metal plate 83 is detachable from the magnet plate 82. Then, the magnet plate 82 and the metal plate 83
After sandwiching the leading end of the stencil sheet M, the stencil sheet M is rotated, and the stencil sheet M is wound around the outer peripheral surface of the stencil sheet M to perform plate-making. The metal plate 83 rotates about a hinge 84 along the outer peripheral ridge of the plate cylinder 80. The metal plate 83 is at a fixed position attracted to the magnet plate 82 when the stencil sheet M is stenciled. When the stencil sheet M is discharged, the metal plate 83 is opposite to the fixed position about the hinge 84 as shown by a dashed line in the figure. It rotates so as to be attracted to the magnet plate 82 at the position.

[0004]

However, in the above-described conventional stencil printing apparatus, a range in which the metal plate 83 rotates on the outer peripheral surface of the plate cylinder 80, that is, as shown in FIG. It was necessary to secure an area twice the width L. For this reason, the outer peripheral length of the plate cylinder 80 is increased, which hinders downsizing of the plate cylinder 80.

In the stencil printing apparatus, the printing cylinder 80 is rotated during printing, and the printing paper P and the stencil sheet M are pressed against each other by the press roller 85 urged toward the printing drum 80. When the plate cylinder 80 rotates during this printing, the metal plate 8
3 and the hinge 84, etc., to avoid contact with the press roller 85, each time the metal plate 83 or the like passes, the plate cylinder 80
Control for retracting the press roller 85 from the side is required. Since the press roller 85 presses the printing paper P against the stencil sheet M with a predetermined pressing force during printing, a mechanism for retracting the press roller 85 against the pressing force at a predetermined timing is complicated. This hinders miniaturization of the entire apparatus. Further, after the press roller 85 is retracted from the plate cylinder 80 side, the operation sound of contacting the plate cylinder 80 again is generated.
It was generated continuously during the rotation of 0, and was considered as one of the causes of noise and vibration.

Therefore, in order to solve the above-mentioned problems, the present invention can reduce the size of the plate cylinder by reducing the area required for forming a stencil sheet, and reduce noise and vibration caused by the printing operation. It is an object to provide a stencil printing apparatus.

[0007]

According to the present invention, there is provided a stencil printing apparatus according to the first aspect of the present invention, wherein the peripheral wall of the ink-permeable plate has a cylindrical shape and is rotatable about its own axis. A stencil printing apparatus for wrapping a stencil sheet made on the outer peripheral surface of the plate cylinder, comprising a charge applying means for applying a charge to the outer peripheral surface of the plate cylinder; Characterized in that it is adsorbed and held on the outer peripheral surface.

The stencil printing apparatus according to the second aspect is the first aspect.
In the stencil printing machine described above, the stencil sheet is defined to be longer than the outer peripheral length of the plate cylinder, and the ends thereof overlap and are fixed and held to the plate cylinder.

According to a third aspect of the present invention, there is provided a stencil printing apparatus.
Alternatively, in the stencil printing apparatus according to claim 2, the plate cylinder is electrically insulated by its own axis.

[0010]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a side view showing a stencil printing apparatus of the present invention.

As shown in FIG. 1, the stencil printing apparatus has an original reading unit 1, a stencil making unit 2, a printing unit 3, a paper feeding unit 4, a paper discharging unit 5, and a stencil discharging unit 6. ing.

The document reading section 1 is arranged above the stencil printing apparatus, and can read a book-bound document (hereinafter referred to as a book document) and a sheet-shaped document (hereinafter referred to as a sheet document). It is configured.

A configuration for reading a book document and a sheet document for each sheet is, for example, an endless belt 9 attached to a pair of rollers 8.
1, a line image sensor 10 that moves in the left-right direction in FIG. 1, a document mounting glass table 11 on which each document is mounted, and an openable and closable mounted on the document mounting glass table 11. Pressure plate 12.

When reading each original, the surface to be read of a book original or a sheet original is placed on the original mounting glass table 1.
1 is placed downward, and pressed from above by the pressure plate 12. Then, the line image sensor 10 is moved. The line image sensor 10 scans at a predetermined speed between the home position A and the scan end position B shown in FIG. As a result, the image of the original on the original placing glass table 11 is read.

The stencil printing apparatus includes an automatic document feeder 13 for sequentially reading a plurality of sheet documents. The automatic document feeder 13 has a document set tray 14 on which a plurality of sheet documents are stacked.
Sheet documents on the document set tray 14 are fed into the automatic document feeder 13 one by one by the respective transport rollers 15. The line image sensor 10 is moved to the position C (shown in FIG. 1) directly below the automatic document feeder 13 by the moving mechanism and fixedly arranged. As a result, the image of the scanned sheet document is read. After completion of the reading, the sheet document is sent out to the pressure plate 12 outside the automatic document feeder 13.

Next, the stencil making section 2 is composed of a stencil paper roll section 17 in which a heat-sensitive stencil sheet M made of a continuous sheet is stored in a roll form, and a plurality of point heating elements arranged in a horizontal line. The thermal head 18, a platen roller 19 disposed opposite to the thermal head 18, each stencil feed roller 20, a stencil guide roller 21, and the stencil cutter 2.
And 2. The stencil sheet M stored in the stencil roll section 17 is formed by laminating polyester gauze on a polyester film, for example.

The stencil making section 2 feeds the stencil sheet M pulled out from the stencil roll section 17 by sandwiching the stencil sheet M between the thermal head 18 and the platen roller 19 by the rotation of the platen roller 19. Image information on an image of a document read by the document reading unit 1 is input to the thermal head 18. The thermal head 18 selectively heats each of the point heating elements individually in accordance with the image information, and performs dot matrix heat-sensitive perforation on the stencil sheet M. The document guide roller 21 is provided with a silicon damper or the like serving as a tension applying mechanism at a shaft portion thereof, and appropriately applies tension to the stencil sheet M sent between the thermal head 18 and the platen roller 19. The stencil feed roller 20 sends the stencil sheet M, which has been made, to the plate cylinder 6 side. The stencil sheet M that has been made is cut by the stencil cutter 22 into one plate.

Next, the printing section 3 has a plate cylinder 24. The plate cylinder 24 is composed of two opposing side plates 2 formed in a disk shape.
A peripheral wall 26 is wound around the outer periphery of 5 to form a cylindrical shape. Peripheral wall 26
Has a rectangular shape at the center where the ink-permeable printing area is developed by a porous structure. Around the print area,
It has a non-printing area through which ink does not pass.

The cylindrical plate cylinder 24 is driven to rotate about its own axis about a central axis 27 supporting each side plate 25. The bearing member 28 interposed between the side plate 25 and the center shaft 27 for rotating the plate cylinder 24 is made of an insulating material. Therefore, the rotating plate cylinder 24 is placed on its own axis and is electrically insulated from other components.

The plate cylinder 24 is provided with charge applying means 29. As shown in FIG.
Is mainly composed of a power supply unit 29a and a switch 29b,
When the switch 29a is turned on, a charge is applied to the plate cylinder 24. The peripheral wall 26 of the plate cylinder 24 to which an electric charge is applied is formed by arranging a mesh-shaped dielectric 26b on the outer peripheral surface of a metal drum 26a having a porous structure. In the present embodiment, charge is applied to the metal drum 26a by the charge applying means 29. The volume resistivity of the dielectric 26b is 1011Ω.
cm or more. A switch 29c is grounded at one end in order to release the charge applied to the plate cylinder 24.

Inside the plate cylinder 24, an ink supply means for supplying ink to the inner peripheral surface of the peripheral wall 26 is provided. The ink supply means mainly includes a squeegee roller 30 and a doctor roller 31. The squeegee roller 30 is provided along the axis of the plate cylinder 24 so as to contact the inner peripheral surface of the peripheral wall 26 (metal drum 26a). The doctor roller 31 is provided at a predetermined interval on the squeegee roller 30 in parallel with the squeegee roller 30. The ink supply means forms a wedge-shaped ink reservoir portion 32 at a predetermined interval between the squeegee roller 30 and the doctor roller 31, and measures the ink at the predetermined interval while forming the wedge-shaped ink reservoir 32 through the outer peripheral surface of the squeegee roller 30. Supply ink to the inner peripheral surface. The squeegee roller 30 is attached to the peripheral wall 26 (the metal drum 26
The inner peripheral surface shown in FIG.

The printing section 3 has a press roller 33 parallel to the axis of the plate cylinder 24. Press roller 33
Are supported by a driving device (not shown) via a rotating shaft 34. The press roller 33 can be moved substantially vertically between a retracted position separated from the outer peripheral surface of the plate cylinder 24 by the driving device and a pressure contact position pressed against the outer peripheral surface of the plate cylinder 24. . The press roller 33 presses the printing paper P against the stencil sheet M on the outer peripheral surface of the plate cylinder 24 when in the pressing position. Thereby, the ink supplied to the inner peripheral surface of the peripheral wall 26 by the ink supply means passes through the perforated portion of the stencil sheet M from the ink-permeable portion of the peripheral wall 26, and transfers a desired image to the printing paper P.

Next, the paper supply section 4 has a paper supply table 36 on which the printing paper P is loaded. Printing paper P on paper feed table 36
Are taken out one by one by a paper feed roller 37 and a paper separating roller 38. The taken out printing paper P is sent to the timing roller pair 4 via the upper and lower paper guide members 39.
It is transported to the nip portion of 0. Timing roller pair 40
Sends out the printing paper P between the plate cylinder 24 and the press roller 33 at a predetermined timing.

Next, the paper discharging section 5 is provided with a peeling claw 42 for peeling the printing paper P printed by the printing section 3 from the plate cylinder 24.
have. Printing paper P peeled off from plate cylinder 24
Is conveyed to a paper discharge table 44 by a belt conveyor type paper discharge conveyance device 43. The paper discharging and conveying device 43 is configured to
43a for transporting the sheet toward the sheet discharge table 44, and the plate cylinder 2
And a suction unit 43b for adsorbing the printing paper P peeled off from the belt 4 onto the belt 43a. As a result, the printing papers P that have been sequentially printed are stacked on the paper discharge tray 44 with the print image surface facing upward.

Next, the plate discharge section 6 has a plate discharge separation claw 46 for peeling the used stencil sheet M wound around the outer peripheral surface of the plate cylinder 24 from the plate cylinder 24. The stencil sheet M is transferred to the plate cylinder
4, the edge of the stencil sheet M is hooked by the stencil separation claw 46 as the plate cylinder 24 rotates. The stencil sheet M caught on the plate discharging separation claw 46 is peeled off from the outer peripheral surface of the plate cylinder 24 by further rotation of the plate cylinder 24. Further, the stencil sheet M peeled off by the plate discharging separation claw 46 is conveyed by a plate discharging roller pair 47 and stored in a plate discharging box 48.

In the above-described stencil printing apparatus, a stencil printing operation for winding the stencil sheet M on the outer peripheral surface of the plate cylinder 24 will be described below.

First, in the plate making operation, plate making on the stencil sheet M is performed in the plate making section 2. The stencil making of the stencil sheet M is as described above, and the stencil sheet M that has been made stencil is put on standby with its leading end nipped by the stencil feed rollers 20 on the plate cylinder 24 side. Next, switch 2 of charge applying means 29
9b is turned on, and a charge is applied to the plate cylinder 24. At this time, since the bearing member 28 on the center shaft 27 for rotating the plate cylinder 24 is made of an insulating material, the electric charge by the charge applying means 29 does not involve other parts than the plate cylinder 24. Next, the leading end of the stencil sheet M is sent out toward the plate cylinder 24 by the stencil feed roller 20. The leading end of the stencil sheet M sent out is a plate cylinder 2
4 is attracted to the outer peripheral surface of the peripheral wall 26. Next, while the stencil sheet M is fed by the stencil feed roller 20, the plate cylinder 24 is rotated counterclockwise in FIG. As a result, the stencil sheet M is wound in the circumferential direction of the peripheral wall 26 while the stencil sheet M is attracted to the outer peripheral surface of the peripheral wall 26.

In the plate making operation, the stencil sheet M cut by the stencil cutter 22 is cut into one plate in the plate making section 2. In the present stencil printing apparatus, the cut stencil sheet M is defined to be longer than the outer peripheral length of the stencil sheet M in the rotation direction of the plate cylinder 24. As a result, the stencil sheet M wound around the plate cylinder 24 is held on the outer peripheral surface of the peripheral wall 26 with the rear end overlapping the front end.

After the printing, printing is performed. When printing,
One print sheet P on the sheet supply table 36 is taken out and transported to the nip portion of the timing roller pair 40. Next, plate cylinder 2
4 rotates counterclockwise in FIG. 1, the timing roller pair 40 causes the printing paper P to be
4 and between the press roller 33. At the same time, the press roller 33 moves to the pressing position, and presses the printing paper P against the stencil sheet M on the outer peripheral surface of the plate cylinder 24. Thus, the ink supplied to the inner peripheral surface of the peripheral wall 26 by the ink supply means passes through the perforated portion of the stencil sheet M via the ink-permeable portion of the peripheral wall 26, and a desired image is transferred to the printing paper P. Then, printing is performed. Subsequently, the printed printing paper P is peeled off from the plate cylinder 24 by the peeling claw 42 and is discharged to the discharge tray 44 via the discharge conveyance device 43.

After the printing is completed, the printed stencil sheet M
Is held on the plate cylinder 24 in a state where the plate is applied. By wrapping the printed stencil sheet M around the printing drum 24 in this manner, the ink inside the printing drum 24 and the ink held on the peripheral wall 26 are prevented from drying out. This printed stencil sheet M
Is discharged when the stencil sheet M for the next printing is applied.

In the plate discharging operation, the switch 29b of the charge applying means 29 is turned off, and the switch 29c on the ground side is turned on (energized) to release the charge to the plate cylinder 24. Thereby, the stencil sheet M is formed on the outer peripheral surface of the peripheral wall 26.
Is released, and the rear end of the stencil sheet M becomes free.
Next, the plate cylinder 24 is rotated in the clockwise direction in FIG. Then, the stencil sheet M is peeled off from the plate cylinder 24 so that the trailing end of the stencil sheet M which has been freed is caught by the stencil separation claw 46, and stored in the stencil discharge box 48 by the stencil discharge roller pair 47. During this plate discharging operation, the press roller 33 is set to the retracted position, and the squeegee roller 30 is moved to the peripheral wall 26 (metal drum 26).
The supply of ink to the inner peripheral surface of the peripheral wall 26 is stopped by separating from the inner peripheral surface of a).

The rotation of the plate cylinder 24 in each of the above-described operations such as plate-making, printing, and plate discharging is controlled by a pulse motor or the like based on the rotation angle of the plate cylinder 24 detected by a detector (not shown). The positions of the leading end and the trailing end of the stencil sheet M at the time of stencil detection are detected by a detector 50 arranged near the plate cylinder 24, and are used for rotation control of the plate cylinder 24.

Therefore, in the stencil printing apparatus thus configured, the stencil sheet M is attracted and held by the charge applied to the plate cylinder 24 to perform stencil printing. This eliminates the need for a clamp mechanism or the like that clamps the leading end of the stencil sheet M, so that the outer peripheral area of the plate cylinder 24 can be reduced and the size of the plate cylinder 24 can be reduced.

Further, during printing, since the press roller 33 does not move to avoid the unnecessary collision with the clamp mechanism or the like, noise and vibration due to the printing operation can be reduced. Further, since a complicated mechanism for retracting the press roller 33 for pressing the printing paper P against the stencil sheet M with a predetermined pressing force at the time of printing is not required at a predetermined timing, it is possible to reduce the size and weight of the entire apparatus. Becomes Further, since the press roller 33 does not move during printing, the pressing force of the press roller 33 against the plate cylinder 24 becomes uniform, so that the image density on the printing paper P can be stabilized.
The press roller 33 can be moved to a retracted position separated from the outer peripheral surface of the peripheral wall 26.
The movement of the sheet No. 3 to the retreat position is performed at the time of plate discharge other than the time of printing or at the time of conveyance failure (jam) of the printing paper P.

In the stencil printing apparatus, the length of the stencil sheet M cut into one plate is defined to be longer than the outer peripheral length of the plate cylinder 24, and the stencil sheet M wound around the plate cylinder 24 is defined. The rear end overlaps the front end. As a result, the entire outer periphery of the stencil sheet 24 is covered with the stencil sheet M.
There is no risk of ink leakage from between the (peripheral wall 26).
If the entire outer periphery of the plate cylinder 24 is covered with the stencil sheet M as described above, the ink-permeable printing area of the peripheral wall 26 can be formed over the entire periphery of the plate cylinder 24.
It is not necessary to define the position for holding the leading end of the stencil sheet M with respect to the outer circumference of the stencil sheet. That is, it is possible to control the rotation of the plate cylinder 24 only at the leading end position of the stencil sheet M without positioning the rotational position of the plate cylinder 24 and the leading end position of the stencil sheet M.

[0036]

As described above, in the stencil printing machine according to the first aspect of the present invention, electric charges are applied to the outer peripheral surface of the plate cylinder, and the electric charges cause the stencil sheet to be sucked and held on the outer peripheral surface of the plate cylinder. This eliminates the need for a configuration such as a clamp mechanism for holding the leading end of the stencil sheet, and makes it possible to reduce the outer peripheral area of the plate cylinder and reduce the size of the plate cylinder.

In addition, the configuration in which the printing paper is pressed against the stencil sheet with a predetermined pressing force at the time of printing eliminates a complicated mechanism for avoiding the unnecessary clamping mechanism or the like at a predetermined timing, so that the entire apparatus can be reduced in size and weight. And noise and vibration during printing can be reduced.

In the stencil printing machine according to the second aspect, the stencil sheet is defined to be longer than the outer peripheral length of the plate cylinder, and the edges thereof overlap and are fixed and held on the plate cylinder. Accordingly, the entire outer periphery of the stencil sheet is covered with the stencil sheet, so that ink leakage from between the stencil sheet and the plate cylinder (peripheral wall) can be prevented.

In the stencil printing machine according to the third aspect, the plate cylinder is electrically insulated around its own axis. For this reason,
The charge by the charge applying means does not involve other than the plate cylinder, preventing the stencil paper or printing paper from being charged at the time of stencil making, and preventing poor transport of the stencil paper or printing paper.

[Brief description of the drawings]

FIG. 1 is a side view showing a stencil printing apparatus of the present invention.

FIG. 2 is a side view showing a charge applying unit and a peripheral wall.

FIG. 3 is a side view showing a conventional stencil printing apparatus.

[Explanation of symbols]

24: plate cylinder, 26: peripheral wall, 29: charge applying means, M: stencil sheet.

Claims (3)

[Claims] 1. A stencil printing machine having a plate cylinder having an ink-permeable peripheral wall formed in a cylindrical shape and rotatable around its own axis, and winding a stencil sheet made on the outer peripheral surface of the plate cylinder. A stencil printing apparatus, comprising: charge applying means for applying a charge to an outer peripheral surface of the plate cylinder, wherein the stencil sheet is sucked and held on the outer peripheral surface of the plate cylinder by the electric charge. 2. The stencil printing machine according to claim 1, wherein the stencil sheet is defined to be longer than the outer peripheral length of the plate cylinder, and the ends thereof overlap and are fixedly held on the plate cylinder. . 3. The stencil printing apparatus according to claim 1, wherein the plate cylinder is electrically insulated by its own axis.