JPH10100528A - Stencil printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a stencil printer. SOLUTION: A mechanism wherein an ink feed roller 24 gives force for pushing a peripheral wall 16 of a plate cylinder 10 and a mechanism adjusting the pushing force are provided inside the plate cylinder 10, and an inner space of the plate cylinder 10 is effectively used. The mechanism which gives the pushing force is composed of a lever 28 wherein an ink feed roller 24 is supported at its one end, and a spring is fitted to the other end. Then, pushing force is generated with energizing force of the spring 40. Further, a mechanism adjusting the pushing force is a pushing force adjusting mechanism 42 wherein a supporting point 46a at an end part on an opposed side to the end fitted to the lever 28 of the spring 40 is transferred. By transfer of the supporting point 46a, an elongated amount of the spring 40 is varied, and the pushing force can be adjusted. Further, when the ink feed roller 24 is separated from the peripheral wall 16 of the plate cylinder, a load applied to a lever support shaft 32 or the like can be reduced by decreasing elongation of the spring 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention A stencil sheet perforated according to the content of printing is wound around the outer peripheral surface of a plate cylinder, ink is supplied from the inside of the plate cylinder, and the ink passed through the plate cylinder and the stencil sheet is applied to the stencil sheet. The present invention relates to a stencil printing machine that performs printing on a contacting recording medium.

[0002]

2. Description of the Related Art A stencil printing machine is known as a kind of a printing machine which has been widely used at present. The stencil printing machine includes a plate cylinder having a cylindrical peripheral wall having ink passage properties, and an ink supply roller for supplying ink from the inside of the plate cylinder to the peripheral wall. At the time of actual printing, a stencil sheet perforated according to the content of printing is wound around the outer circumference of the plate cylinder, and a recording medium such as paper is placed between the plate cylinder around which the stencil sheet is wound and a platen roller opposed thereto. (Hereinafter simply referred to as paper) to perform printing. The ink supplied to the inner surface of the peripheral wall by the ink supply roller passes through the plate cylinder and the perforation of the stencil sheet and adheres to the sheet, thereby performing printing.

In order to cause the ink supplied to the inner surface of the peripheral wall of the plate cylinder to seep out to the outer surface of the peripheral wall of the plate cylinder, the ink supply roller and the platen roller hold the sheet with a predetermined force. This pinching force needs to be adjustable in order to adjust the print density. Japanese Patent Laying-Open No. 4-148975 discloses a printing machine in which a platen roller is moved in the direction of a plate cylinder by a cam, and a sheet is pinched together with an ink supply roller. In this printing machine, the force for pinching the paper can be adjusted by adjusting the pressing force generated by the platen roller. Japanese Patent Application Laid-Open No. 61-188180 discloses a printing machine capable of moving a platen roller to pinch a sheet together with an ink supply roller, and displacing the ink supply roller to adjust a pinching force of the sheet. It has been disclosed.

[0004]

In the printing machine disclosed in the above-mentioned publication, a mechanism for driving the platen roller is required, and the entire apparatus becomes large in size to secure a space for disposing this mechanism. There was a problem. Also,
There must be no space inside the plate cylinder because a mechanism to supply paper or to wrap stencil paper around the plate cylinder or remove used stencil paper from the plate cylinder cannot be provided inside the plate cylinder. It was a space with a low utilization rate as a whole.

The present invention has been made to solve the above-mentioned problems, and has as its object to provide a small-sized printing machine in which the arrangement of internal mechanisms is optimized.

[0006]

In order to achieve the above-mentioned object, a stencil printing machine according to the present invention comprises a plate cylinder on which a stencil sheet is wound around an outer peripheral surface of an ink-permeable cylindrical peripheral wall; An ink supply roller that is in contact with the inner periphery of the peripheral wall and supplies ink to the inner peripheral surface of the peripheral wall, and is provided inside the plate cylinder;
An elastic member for applying a pressing force by which the ink supply roller presses the peripheral wall of the plate cylinder; and a pressing force of the elastic member provided inside the plate cylinder for moving a supporting point of the elastic member on a printing machine main body side. And a pressing force adjusting mechanism for adjusting the pressure.

According to this structure, since the mechanism for pressing the ink supply roller against the peripheral wall of the plate cylinder and the mechanism for adjusting the pressing force are provided inside the plate cylinder, the number of mechanisms provided outside the plate cylinder can be reduced. In addition, the size of the device can be reduced.

Further, in the stencil device, the pressing force adjusting mechanism includes a frame fixed to a printing press main body side;
The arm may be provided with a support point that is movable with respect to the frame and supports the elastic member, and an arm driving mechanism that drives the arm.

According to this, by moving the position of the support point of the elastic member, even if the ink supply roller is at the same position, the biasing force of the elastic member applied thereto can be changed. Therefore, the force for pinching the sheet, the peripheral wall of the plate cylinder, and the stencil sheet can be adjusted.

Further, the stencil device includes a lever for transmitting the elastic force of the elastic member to the ink supply roller, and a cam for driving the lever to separate the ink supply roller from the inner peripheral surface of the plate cylinder. When the lever is driven by the cam, the pressing force adjusting mechanism may control to move the support point in a direction in which the urging force of the elastic member is reduced.

When the ink supply roller is separated from the plate cylinder by the cam, this movement is a movement in the direction of increasing the urging force on the elastic member. Therefore, the fulcrum of the lever,
A large force is applied to a support point, a cam shaft, etc., at which the elastic member is supported by the device. According to the present invention, the force acting on each part can be reduced by moving the support point of the elastic member in a direction in which the urging force of the elastic member is reduced.

Further, in the stencil printing machine, the pressing force adjusting mechanism includes a contact member that moves together with the arm, and when the ink supply roller is separated by the cam, the contact member is connected to a lever. The ink supply roller may be in direct or indirect contact with the ink supply roller and held at the separated position.

According to this, it is not necessary to hold the ink supply roller at the separated position by the cam. Therefore, there is no need to supply a holding current for fixing the cam, and power consumption can be reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments (hereinafter referred to as embodiments) of a stencil printing machine according to the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show a plate cylinder of a stencil printing machine according to the present embodiment and the internal structure thereof. Plate cylinder 10
Are instructed to be rotatable about a plate cylinder shaft 14 fixedly supported on the frame 12. The plate cylinder 10 has a substantially cylindrical plate cylinder peripheral wall 16, and the plate cylinder peripheral wall 16 is provided with a large number of ink holes 16 a that allow ink to pass from inside to outside of the plate cylinder 10. A stencil sheet 18 is wound around the outer peripheral surface of the plate cylinder 10. The stencil master 18 is created by piercing according to the print content, and is replaced every time the print content changes. Further, the plate cylinder 10 is provided with a clamp mechanism 20 for holding a leading portion of the stencil sheet 18.

A platen roller 22 is provided on the outer periphery of the plate cylinder 10 so as to be in contact therewith. In the plate cylinder 10, an ink supply roller is located at a position where the plate cylinder peripheral wall 16 can be held together with the platen roller 22. 24 are arranged. The paper 26 is supplied between the platen roller 22 and the ink supply roller 24 and is sandwiched between the two rollers together with the plate cylinder peripheral wall 16 and the stencil sheet 18, so that ink adheres to the paper 26 and printing is performed. .

The ink supply roller 24 is rotatably supported by a lever 28. The lever 28 is rotatably supported by a lever support shaft 32 provided on an inner frame 30 fixed to the plate cylinder shaft 14. A doctor roller 34 is rotatably supported on the lever support shaft 32.
The outer periphery of the doctor roller 34 is close to the outer periphery of the ink supply roller 24, and ink is supplied from an ink supply pipe 36 to a portion sandwiched between the two rollers.
8 are formed. The ink supply pipe 36 is provided in parallel with the ink supply roller 24 and the doctor roller 34 and substantially above an ink reservoir 38 formed between these rollers. The ink is supplied to the ink supply pipe 36 from the outside of the plate cylinder 10 through the inside of the plate cylinder shaft 14. The ink in the ink reservoir 38 adheres to the outer periphery of the ink supply roller 24 and is supplied to the inner peripheral surface of the plate cylinder peripheral wall 16 with the rotation of the roller 24. Then, the ink reaches the paper 26 through the ink holes 16 a in the peripheral wall and the perforations of the stencil sheet 18.

One end of a spring 40 as an elastic member is attached to the end of the lever 28 opposite to the end on which the ink supply roller 24 is supported. If the elastic force is transmitted to the lever 28, the spring 40 may be connected to the lever 28 via another component. The other end of the spring 40 is connected to a part of the pressing force adjusting mechanism 42,
It is attached in a state where it is extended from the free length of the spring 40. Therefore, by the urging force corresponding to this growth,
A moment is generated to rotate the lever 28 clockwise in the drawing. Therefore, a pressing force for pressing the ink supply roller 24 against the plate cylinder peripheral wall 16 is applied by the urging force.

The pressing force adjusting mechanism 42 is provided in the inner frame 30.
, And an arm 46 that is movable with respect to the frame in a direction substantially coincident with the direction in which the springs 40 are arranged. The spring 40 is connected to the arm 46.
At one end of the support point 46a. Arm 4
6 is provided with a slit 46b that engages with two T-shaped protrusions 44a provided on the base frame 44, whereby the arm 46 is movably supported by the base frame 44. The base frame 44 includes a gear 4
An adjustment nut 54 is provided, which is rotated by an adjustment motor 52 via 8, 50. The adjustment nut 54 is screwed with an adjustment screw rod 56, and the adjustment screw rod 56 is fixedly supported on the arm 46 via an adjustment screw rod fixing member 58. Therefore, when the adjustment nut 54 is rotated by the adjustment motor 52, the adjustment screw rod 56 and the arm 46 move substantially in the tensioning direction of the spring 40. By this movement, the amount of extension of the spring 40 can be adjusted, and the force with which the ink supply roller 24 presses the plate cylinder 10 and the sheet 26 against the platen roller 22 can be adjusted.

In the plate cylinder 10, there is provided a lift mechanism for moving the ink supply roller 24 toward the center of the plate cylinder 10 when printing is not being performed and separating the ink supply roller 24 from the peripheral wall of the plate cylinder. The lift mechanism 60 is provided on the lever support shaft 3 of the lever 28.
2 has a cam follower 62 provided at the end supporting the ink supply roller 24 and a lift cam 64 that comes into contact with the cam follower 62. further,
The lift mechanism 60 includes a camshaft 6 supporting a lift cam 64.
6, a gear 70 that meshes with the gear 68, and a lift motor 72 that drives the gear 70.

When the printing operation is not being performed, the lever 28 is rotated counterclockwise in the figure by the lift cam 64 driven by the lift motor 72, and moves to the position shown by the two-dot chain line in the figure. Accordingly, the ink supply roller 24
Also moves to a position separated from the plate cylinder peripheral wall 16. The rotation of the lever 28 functions to further extend the spring 40, and therefore, the pressing force adjusting mechanism 42 and the lever support shaft 3
2 and the load applied to the lift mechanism 60 increase. In order to reduce this load, the pressing force adjustment mechanism 42
6 is moved in the lower left direction in FIG. 1 to, for example, a position indicated by a two-dot chain line in the figure. Thereby, the support point 46
a moves, the extension of the spring 40 is reduced, and the urging force of the spring 40 is reduced.

FIG. 3 shows the configuration of the control circuit of this embodiment. The paper sensor 74 detects that the paper is stored in the paper holder, and sends it to the central processing unit (CPU) 76 as a detection signal. The CPU 76 does not perform the printing operation when the paper is not in the holder. Further, a plate cylinder position sensor 78 for detecting the rotational position of the plate cylinder 10 is provided, and a position signal is sent to the CPU 76. CPU76
Control means for controlling the printing drum rotation driving means 80 for rotating the printing drum 10 based on the position signal, controlling the paper feeding means 82 for supplying paper between the printing drum 10 and the platen roller 22 and discharging the paper therefrom. I do. Further, the CPU 76 also controls the adjustment motor 52 and the lift motor 72 via the drivers 52a and 72a.

Next, the operation at the time of printing will be described. Before the printing operation is started, the ink supply roller 24 is held at a position separated from the plate cylinder peripheral wall 16 by the lift mechanism 60. The pressing force adjusting mechanism 42 also moves to the position where the urging force of the spring 40 is reduced, that is, the position indicated by the two-dot chain line in FIG.

When printing is instructed, the CPU 76 instructs the plate cylinder rotation driving means 80 to rotate the plate cylinder 10. When the plate cylinder position sensor 78 detects that the plate cylinder 10 has rotated to a predetermined position, the CPU 76 instructs the sheet conveying means 82 to supply a sheet. And C
The PU 76 controls the lift motor 72 so that the ink supply roller 24 is in contact with the plate cylinder peripheral wall 16 when the paper 26 reaches the platen roller 22, and rotates the lift cam 64. Further, in synchronization with this, when the paper 26 reaches the platen roller 22, the CPU 76 controls the adjustment motor 52 so that the ink supply roller 24 generates a predetermined pressing force, and moves the arm 46.

When the ink supply roller 24 is moved to the separated position after printing is completed, the CPU 76 controls the lift motor 72 to rotate the lift cam 64, and moves the lever 28 to the position indicated by the two-dot chain line in FIG. By rotating, the ink supply roller 24 is separated from the plate cylinder peripheral wall 16. Also, in synchronization with this, the adjustment motor 52 is controlled, and the arm 46 is moved to the position shown in FIG.
By rotating the spring 40 to the position indicated by the two-dot chain line, the urging force of the spring 40 is reduced, and the load applied to the lever support shaft 32 and the like is reduced.

The density adjustment of printing is performed as follows. To increase the print density, the arm 46 is moved in the direction in which the spring 40 extends further, and the ink supply roller 24 is moved.
Increase the pressing force. When it is desired to reduce the print density, the arm 46 is moved in the direction in which the extension of the spring 40 is reduced, and the pressing force of the ink supply roller 24 is reduced. Since the adjusting nut 52 and the adjusting screw bar 56 of the pressing force adjusting mechanism 42 have a self-holding function,
After the position is determined by the rotation of the adjustment motor 52, the position does not change even if the arm 46 receives an external force.

The adjusting motor 52 and the lift motor 72
Rotation does not need to be perfectly synchronized,
4 reaches the position of the platen roller 22, the ink supply roller 24 can generate a predetermined pressing force.
Is located at the separated position, and may be at a position where the extension of the spring 40 is reduced. In other words, there is no problem even if the rotation of the adjustment motor 52 and the lift motor 72 is performed before and after the above condition is achieved.

As described above, according to the present embodiment, the plate cylinder peripheral wall 1
6. A mechanism for applying a force for clamping the stencil sheet 18 and the sheet 26 and a mechanism for adjusting the clamping force
0, it is not necessary to provide these mechanisms outside the plate cylinder 10. by this,
The size of the entire device can be reduced. In addition, since the spring 40 can be contracted except during printing, the load applied to the lever support shaft 32 and the like can be reduced.
The weight of each member can be reduced.

FIG. 4 shows another embodiment according to the present invention. In the description of the present embodiment, the same components as those of the embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof will be omitted. The feature of this embodiment is that the arm 46 of the pressing force adjusting mechanism 42
The point is that a contact rod 84 that moves in synchronization with the contact rod 84 is provided. The contact rod 84 can be formed integrally with the arm 46 or the adjusting screw rod fixing member 58. The ink supply roller 24 is located at a position distant from the peripheral wall 16 of the plate cylinder.
When 6 moves, it contacts a part of lever 28. By the self-holding function of the pressing force adjusting mechanism 42 described above, even if the lift cam 64 is separated from the cam follower 62, the position of the lever 28 is held so that the ink supply roller 24 is at the separated position. Therefore, the contact rod 8
4 functions as a contact member that comes into contact with the lever 28 when the ink supply roller 24 is separated by the lift cam 64 and holds the ink supply roller 24 at the separated position. If the position of the lever 28 is maintained, the contact rod 84 may be configured to be indirectly contacted with the lever 28 via another component.

As described above, according to this embodiment, the same effects as those of the embodiment shown in FIGS.
Further, the following effects can be obtained. That is, the contact rod 84 can reliably hold the ink supply roller 24 at the separated position by the pressing force adjusting mechanism 42 having a self-holding function. Therefore, even when it is necessary to reliably hold the ink supply roller 24 at the separated position, it is not necessary to provide the lift mechanism 60 with a holding function. When the lift mechanism 60 has a holding function, for example, a holding current may be supplied to the lift motor 72, but this is not preferable because power is consumed. In the case of the present embodiment, since energy such as electric power is not consumed to hold the ink supply roller 24 at the separated position, running costs can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a preferred embodiment of a stencil printing machine according to the present invention, as viewed from a plate cylinder axis direction.

FIG. 2 is a schematic configuration diagram of the embodiment, and shows a state viewed from a direction orthogonal to a plate cylinder axis.

FIG. 3 is a control block diagram schematically illustrating a control circuit according to the present embodiment.

FIG. 4 is a schematic configuration diagram of another embodiment of the present invention.

[Explanation of symbols]

10 plate cylinder, 12 frame, 16 plate cylinder peripheral wall, 18
Stencil sheet, 22 platen roller, 24 ink supply roller, 26 sheets, 28 lever, 32 lever support shaft, 40 spring, 42 pressing force adjustment mechanism, 46 arm, 46a support point, 52 adjustment motor, 60 lift mechanism, 64 lift cam, 72 lift motor, 84
Contact rod.

Claims (4)

[Claims] 1. A plate cylinder on which a stencil sheet is wound around an outer peripheral surface of an ink-permeable cylindrical peripheral wall; an ink supply roller which is in contact with the inner peripheral surface of the plate cylinder and supplies ink to the inner peripheral surface of the peripheral wall; An elastic member provided inside the plate cylinder and applying a pressing force for the ink supply roller to press the peripheral wall of the plate cylinder; and a printing machine main body side support point of the elastic member provided inside the plate cylinder and moving the elastic member. And a pressing force adjusting mechanism for adjusting the pressing force of the elastic member. 2. The stencil printing machine according to claim 1, wherein the pressing force adjusting mechanism is a frame fixed to a printing press main body, and a support that is movable with respect to the frame and supports the elastic member. A stencil printing machine including an arm provided with dots and an arm driving mechanism for driving the arm. 3. The stencil printing machine according to claim 2, further comprising: a lever for transmitting the elastic force of the elastic member to the ink supply roller; and driving the lever to move the ink supply roller to the inner periphery of the plate cylinder. A stencil printing press, wherein the pressing force adjusting mechanism moves the support point in a direction in which the urging force of the elastic member is reduced when the lever is driven by the cam. 4. The stencil printing machine according to claim 3, wherein the pressing force adjusting mechanism includes a contact member that moves together with the arm, and the pressing unit adjusts the pressing force when the ink supply roller is separated by the cam. A stencil printing machine, wherein the contact member directly or indirectly contacts the lever and holds the ink supply roller at a separated position.