JP2593622B2 - Stencil printing machine - Google Patents

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, and more particularly to a printing density adjusting mechanism for a stencil printing apparatus capable of variably setting a printing density.

[0002]

2. Description of the Related Art A stencil printing apparatus for performing stencil printing in a pressing manner by pressing a printing sheet against a stencil sheet wound around the outer periphery of a cylindrical plate cylinder by a press roller is well known.

In the stencil printing apparatus as described above, the pressing force of the press roller against the plate cylinder is variably set in accordance with print density information set by print density information setting means such as a print density setting key provided on an operation panel. It has already been proposed to variably set the print density of an image to be printed on printing paper, and this is disclosed, for example, in Japanese Patent Application Laid-Open No. 62-127276.

[0004]

The printing ink used in a stencil printing machine is often a pigment, a resin, a solvent,
An emulsion ink containing a surfactant, water, or the like, which is known to have a temperature dependency with respect to ink viscosity. The ink viscosity affects the amount of ink transferred to printing paper in stencil printing, which changes the print density including the quality of a printed image (such as the uniformity of a solid image).

That is, in the stencil printing apparatus, one of the factors affecting the printing density is the temperature of the printing ink. When the temperature of the printing ink changes due to a change in the use environment temperature, the printing density changes and becomes constant. The printed matter of the density cannot be obtained.

SUMMARY OF THE INVENTION In view of the above problems, the present invention is configured to automatically compensate for printing density with respect to the temperature of printing ink, and to improve stencil printing at a desired density irrespective of a change in printing ink temperature. The purpose is to provide.

[0007]

In order to achieve the above-mentioned object, a stencil printing apparatus according to the present invention provides a stencil printing machine by pressing a printing paper against a stencil wrapped around the outer periphery of a cylindrical plate cylinder by a press roller. Temperature detecting means for detecting the temperature of the printing ink, and a pressing force for variably setting a pressing force of the press roller to the plate cylinder according to the temperature of the printing ink detected by the temperature detecting means. And a variable setting unit.

[0008]

According to the above construction, the pressing force of the press roller against the plate cylinder is variably set according to the temperature of the printing ink detected by the temperature detecting means.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 is an external view of a stencil printing apparatus 1 according to the present invention.

In FIG. 1, a case 1 of a stencil printing machine 1 is shown.
a on one side of the upper part by a hinge 2a (see FIG. 3).
The cover 2 is opened and the stencil sheet S, which has been made, is set at a predetermined position on the cover 2 during printing.

An operation panel 5 such as a flat keyboard is provided on the case 1a as shown in FIG. The operation panel 5 includes a numeric keypad 5a for setting the number of prints, a print start key 5b, a print stop key 5c,
L for displaying the print density setting key 5d, the printing speed (printing speed) setting key 5e, and the set number of prints
It has a display unit 5f such as a CD display.

FIG. 3 shows the internal mechanism of the stencil printing apparatus 1 according to the present invention.

In FIG. 1, a cylindrical plate cylinder 20 is supported by a machine frame (not shown) so as to be rotatable around its own central axis. The plate cylinder 20 is configured to have a porous structure, and has a clamp mechanism 21 on an outer peripheral portion for detachably engaging one end of the stencil sheet S with respect to the plate cylinder 20.

One end of the stencil sheet S is locked to the plate cylinder 20 by a clamp mechanism 21 and wound around the outer peripheral surface of the plate cylinder 20 to be mounted.

That is, the clamping mechanism 21
And a movable clamp piece 24 pivotally supported by the plate cylinder 20 by a shaft 23 extending along the axial direction of the belt-like permanent magnet 22 fixed to the outer circumferential surface of the plate cylinder and extending along one generatrix.
And A gear 25 is attached to one end of the shaft 23. The gear 25 has a drive gear 27 supported by one end of a lever 26 when the plate cylinder 20 is at an initial rotation position (the position shown in FIG. 3). Engage appropriately.

The lever 26 is pivotally supported by a machine frame (not shown) by a pivot 28, is urged in the counterclockwise direction in the figure by the spring force of a spring 30, and when the solenoid 29 is not energized, the drive gear 27 is located at a pivoting position to separate the gear 27 from the gear 25. On the other hand, when the solenoid 29 is energized, the lever 26
Rotates clockwise in the figure against the spring force of the spring 30, and moves to a rotation position where the drive gear 27 meshes with the gear 25 of the plate cylinder 20 at the initial rotation position. The driving gear 27 is rotationally driven by an electric motor 31 attached to a lever 26, whereby the gear 25 is rotated and the clamp piece 2 is rotated.
4 is driven to rotate between a clamp position attracted to the permanent magnet 22 and an unclamping position which is rotated substantially 180 ° counterclockwise in the figure from the clamp position.

The plate cylinder 20 is drivingly connected to a sprocket 34a provided coaxially with the center shaft 20c.
4a is drivingly connected to a driving sprocket 34b of a motor 33 by an endless chain 32. With this power transmission device, the plate cylinder 20 is intermittently or continuously rotated by a motor 33 in a counterclockwise direction in the figure.

A printing ink supply means 35 is provided inside the plate cylinder 20. The printing ink supply means 35 is provided so as to contact the inner peripheral surface of the plate cylinder 20 at the outer peripheral surface, and is rotatable about its own central axis 37.
6 and a doctor rod 38 extending along the roller generatrix direction with a predetermined minute gap from the outer peripheral surface of the squeegee roller 36. The squeegee roller 36 The printing ink in the ink reservoir A is rotated by being driven to rotate in the same
To the inner peripheral surface of

The printing ink in the ink fountain A passes through a minute gap between the squeegee roller 36 and the doctor rod 38 with the rotation of the squeegee roller 36. At this time, the amount of ink is measured and the outer peripheral surface of the squeegee roller 36 is measured. Then, a printing ink layer having a uniform thickness is formed, and the printing ink layer is carried to the inner peripheral surface of the plate cylinder 20 with the rotation of the squeegee roller 36 and used for printing.

The stencil printing apparatus 1 is provided with a paper feed table 4 that can move up and down. A pinion 48 that is driven to rotate by a motor (not shown) is attached to the paper feed table 4.
A rack 49 having a series of rack teeth 49a with which a pinion 48 meshes is fixedly mounted in the vertical direction on a machine frame (not shown). The rotation of the pinion 48 causes the paper feed table 4 to move up and down in accordance with the load amount of the printing paper P. Driven.

The paper feeding mechanism 60 has rollers 61, 62, 63 made of rubber or the like, takes out the printing paper P one by one from the paper feeding table 4, and presses the printing paper P with the plate cylinder 20 at a predetermined timing. The paper is fed between the rollers 40.

The stencil printing machine 1 is provided with a printed paper peeling claw 80. The paper peeling claw 80 is for peeling the printed paper from the plate cylinder 20, and the peeled printing paper flies to the lower right side in the figure by the inertia force given by the rotation of the plate cylinder 20, Sequentially stacked on the paper output table 3,
The paper is ejected.

A stencil setting plate 10 for setting a stencil sheet S
0, an optical sensor 101 for detecting the presence or absence of the stencil sheet S
Is provided, and the stencil sheet S is
0 is detected, the feed roller 10 is set.
The stencil sheet S is guided to the conveyance path 107 by 2 and 103 and is conveyed toward the clamp mechanism 21 of the plate cylinder 20.

The stencil printing machine 1 has a used stencil sheet S
Is provided from the plate cylinder.

In the stencil printing apparatus 1, the printing paper P is transferred to the plate cylinder 20.
Roller 40 and press roller 40 pressed against
Is provided with a press roller driving device 400 that drives the roller in synchronization with the rotation of the plate cylinder 20.

FIG. 4 is a detailed embodiment diagram of the press roller driving device 400.

A cam 41 that rotates integrally with the plate cylinder 20 is attached to the center shaft 20c of the plate cylinder 20.
A cam follower lever 42 which is pivotally supported at one end by a shaft (not shown) by a machine frame (not shown) is engaged.
The cam follower lever 42 is biased downward in FIG. 4 by a spring (not shown), and the other end is pivotally connected to the lever element 43 by a shaft 42b.

The lever element 43 includes a first lever element 44 directly connected to the cam follower lever 42 by a shaft 42b, and a second lever element 45 provided with a pulse motor 50 and a speed reduction mechanism 51. .

The first lever element 44 is provided with a sliding groove 44b having a U-shaped cross section in which the second lever element 45 slides, and guided by the sliding groove 44b, the two lever elements 44,
Numeral 45 is extendable with respect to each other in the lever length direction. A long hole 46a is formed in the lever element 45, and the lever element 4
Since the engagement terminal 46 attached to 4 engages with the elongated hole 46a, the maximum amount of expansion and contraction of both lever elements 44 and 45 is defined.

The first lever element 44 is provided with a long hole 44a for releasing the central shaft 20c so that the entire lever element 43 can move up and down by the rotation of the press cam 41.

A support plate 47 is bent at the lower end of the second lever element 45, and a pulse motor 50 and a reduction mechanism 51 for reducing the output of the pulse motor 50 are provided on the support plate 47. Have been.

The output shaft of the pulse motor 50 has a gear 50a.
The gear 50a is engaged with a large-diameter gear 52 that constitutes a reduction mechanism 51 together with the gear 50a. At the center of the large-diameter gear 52, a through-hole 52a into which a threaded control rod 53 is screwed is provided. The rotation of the pulse motor 50 is reduced by the engagement between the gear 50a and the large-diameter gear 52, By the screw engagement, the control rod 53 is converted into the axial movement.

A tension coil spring 54 is provided at one end of the control rod 53.
Is locked at one end, and the tension coil spring 54 is locked at the other end to a pin 55 fixed to the first lever element 44,
The second lever element 45 is urged upward with respect to the first lever element 44 in the figure.

The second lever element 45 has a pin 55
A long hole 55a through which a hole is inserted is formed.

One end of a swing lever 56 is connected to the second lever element 45 by a shaft 56b, and the swing lever 56 is pivotally supported at an intermediate portion by a shaft 56a from a machine frame (not shown). I have. A connecting plate 57 and one end of a connecting lever 93 are coaxially fixed to the shaft 56a, and a bracket 59 that supports the press roller 40 so as to be rotatable by a rotating shaft 59a is attached to the connecting plate 57 by a connecting member 58.

A damper 96 for damping vibration is fixed to a machine frame (not shown) by a screw 97. A plunger 91 of the damper 96 has an intermediate portion of a hook lever 92 and the other end of a connecting lever 93 by a shaft 91a. Are rotatably mounted.

An engaging portion 92a bent in an L-shape is provided at the lower end of the hook lever 92, and a projection 56c which is detachably engaged with the engaging portion 92a is provided at the end of the swing lever 56. Is provided. As a result, the swing lever 56 and the connection lever 93 are selectively driven and connected with respect to the rotation of the swing lever 56 in the counterclockwise direction in the drawing.

In the drawing of the connecting lever 93, the maximum amount of rotation in the clockwise direction, in other words, the maximum separation position of the press roller 40 is determined by the adjusting screw 7 screwed to the support member 72.
1 is set to be adjustable.

The hook lever 92 is urged by a spring (not shown) in a clockwise direction in the drawing, that is, in a direction away from the engagement with the swing lever 56.

A plunger lever 94 is rotatably attached to a machine frame (not shown) by a pivot 94a. The plunger lever 94 is selectively rotated clockwise in FIG. The hook lever 92 is turned counterclockwise in the drawing, that is, the swing lever 56.
In the direction of engagement with.

Thus, the swing lever 56 and the connecting lever 93 are driven and connected by the ON operation of the solenoid 98.

In FIG. 4, reference numeral 95 denotes a monitoring sensor for monitoring the position of the press roller 40.

When the cam 41 is in the rotation position shown in FIG. 4, the lever element 43 is in the lower position as a whole,
The press roller 40 is, as shown in FIG.
It is at a remote position away from 0.

In this state, when the center shaft 20c is rotated by 180 degrees counterclockwise in the figure by driving the motor 33, the cam 41 also becomes one as shown in FIG.
By rotating by 80 degrees, the lever element 43 is moved upward as a whole, and the swing lever 56 is rotated counterclockwise in the figure around the shaft 56a.

At this time, the solenoid 98 is pulled, and the engaging portion 92a of the hook lever 92 and the projection 56c of the lever 56 are moved.
Is engaged, the rotation of the swing lever 56 is transmitted to the connection lever 93 via the hook lever 92, whereby the shaft 56a is rotated counterclockwise in the figure,
The press roller 40 moves to the direction of pressing against the outer peripheral surface of the plate cylinder 20, that is, the pressing position, and presses the fed printing paper against the outer peripheral surface of the plate cylinder 20 to perform stencil printing in a pressing manner.

At this time, the movement of the press roller 40 to the pressing action position is performed by raising the first lever element 44 and applying the pulling force to the tension coil spring 54 by the second lever element 44.
Is transmitted to the lever element 45 of the
This is performed by rotating counterclockwise in FIG. 4 around a. The press roller 40 is pressed against the outer peripheral surface of the plate cylinder 20 with the printing paper P interposed therebetween, so that rotation of the swing lever 56 in the counterclockwise direction in FIG. Even when the first lever element 44 is still pulled up, the first lever element 44 is displaced with respect to the second lever element 45, and the tension coil spring 54 expands. As a result, the press roller 4 is pressed by the spring force of the extension of the extension coil spring 54.
0 is pressed against the outer peripheral surface of the plate cylinder 37 across the printing paper P, whereby the pressing pressure, that is, the pressing force is determined by this spring force.

In adjusting the press pressure (pressing force), the large-diameter gear 52 is rotated by driving the pulse motor 50 to change the axial position of the control rod 53 on the second lever element 45. As a result, the mounting length of the tension coil spring 54 changes, and the mounting load of the tension coil spring 54 changes accordingly.

Due to the change in the mounting load of the tension coil spring 54, the pressure for pressing the press roller 40 against the outer peripheral surface of the plate cylinder 20 under the above-described action, that is, the press pressure changes.

The pulse motor 50 is driven in accordance with the temperature of the printing ink detected by a temperature sensor 104, which will be described later, to adjust the pressing force of the press roller 40, and automatically controls the pressing pressure in accordance with the temperature of the printing ink. To correct.

When the motor 33 is driven, the center shaft 20c is moved further counterclockwise by 180 degrees than the state shown in FIG.
When rotated, the plate cylinder 20 returns to the state shown in FIG.
The pressing / separating operation of the press roller 40 with respect to the plate cylinder 20 is repeated in synchronization with the rotation of.

When the printing paper P is not fed, the ON operation of the solenoid 98 is released, the hook lever 92 is disengaged from the swing lever 56, and the swing lever 56 and the connecting lever 93 are disengaged. By breaking the connection with
The press roller 40 always keeps the plate cylinder 2 regardless of the rotation of the cam 41.
It is held at a remote position away from zero.

FIG. 6 shows the electrical components of the stencil printing apparatus 1 as described above.

In the figure, reference numeral 200 denotes a CPU 200 constituted by a microprocessor or the like. The CPU 200 has a ROM 210 storing a program for controlling each mechanism in the apparatus, an operation panel 5, Temperature sensor 104 for detecting the temperature of printing ink
A use state detection mechanism 105 for detecting the use state of the apparatus, such as immediately after the start of printing or a leaving period (non-use period) since the last use, a monitoring sensor 95, a solenoid 98, and a stencil sheet. Optical sensor 10 for detecting the presence or absence of S
1, an optical sensor 90 for detecting that the stencil sheet S has been conveyed to a position where it can be clamped, a plate cylinder driving motor 33 constituting a plate cylinder driving unit for rotating the plate cylinder 20 in a divided or continuous manner. A feed roller driving motor 60M,
Transport roller driving motor 102M for transporting stencil sheet S
An electric driving unit of the clamp mechanism 21, an electric driving unit of the stencil discharging mechanism (stencil sheet removing mechanism) 70, a pulse motor 50, and a pulse for supplying the pulse motor 50 with a number of pulses corresponding to the print density information. A generator 50A and temporarily store the operation result of the microprocessor, or print number setting information input from the ten key 5a of the operation panel 5,
The print speed information set by the print speed setting key 5d, the ink temperature information detected by the temperature sensor 104, the use state information such as the non-use period detected by the use state detection mechanism 105, and the print density setting key 5e are set. RAM 220 for storing print density information as needed.

Next, the essential parts of the present invention will be described with reference to the flowchart shown in FIG.

The stencil sheet S (original) is a stencil sheet set plate 1
When it is set to “00”, the effect is detected by the optical sensor 101 (Yes at step 501), and the print number setting information by the ten keys 5 a of the operation panel 5, the printing speed by the printing speed setting key 5 d and the printing speed by the printing density setting key 5 e respectively. When the print density information is input and set, the respective set information is stored in each area of the RAM 220 (steps 502, 503, and 504), and is set as one of the conditions for the print processing.

When the predetermined print processing information is set in this way, the current temperature of the printing ink and the non-use period since the last time the stencil printing apparatus 1 was used, or the stencil printing The use state information of the stencil printing apparatus 1 including discrimination information as to whether the printing apparatus 1 is about to be used or whether some printing has already been performed is stored in each area of the RAM 220 ( Step 505).

Next, when the print start key 5b is depressed (Yes at step 506), the clamp mechanism 21 is operated based on a command from the CPU 200, used for the previous printing, and wound around the outer circumference of the plate cylinder 20. Stencil sheet S
Is released from the clamped state, and thereafter, is stripped from the outer peripheral surface of the plate cylinder 20 by the plate discharge mechanism 70 and discarded in a plate discharge box (not shown) (step 507).

Next, the transport roller driving motor 102M is driven by the command of the CPU 200, so that the feed roller 102 is rotated and the stencil sheet S is transported to the clamp mechanism 21. When the leading end of the stencil sheet S reaches the clamp mechanism 21, the optical sensor 90 detects that fact, and when a detection signal is transmitted to the CPU 200, the
U200 sends a command to clamp the leading end of the stencil sheet S to the clamp mechanism 21. This makes the stencil sheet S
Is clamped by the clamp mechanism 21.

Then, in response to a command from the CPU 200, the plate cylinder driving motor 33 is driven, the plate cylinder 20 is rotated one turn in the counterclockwise direction in the figure, and the stencil sheet S
Is wound and mounted (step 508).

In the next step 509, the RAM 2
The printing process is performed based on the print ink temperature information and the use state information of the stencil printing apparatus 1 together with the print number setting information, print speed setting information, and print density setting information stored in the printer 20.

That is, in this printing process, the plate cylinder driving motor 33 for driving the plate cylinder 20 to rotate is controlled by the RAM
The printing press is controlled based on the printing speed setting information stored in the printer 220, and the printing process is performed with the printing density set according to the printing speed, the printing ink temperature, and the use state of the stencil printing apparatus 1. Roller 4
A pressure contact force (press pressure) of 0 is controlled.

That is, the CPU 200 comprehensively determines the printing speed, the printing ink temperature, and the use state of the stencil printing apparatus 1 in order to satisfy the printing density of the printing density setting information stored in the RAM 220, thereby generating a pulse. The number of pulses to be supplied to the pulse motor 50 is determined by controlling the device 50A.

Accordingly, the print density setting key 5d shown in FIG.
When the print density is set in the dark direction, the number of pulses supplied to the pulse motor 50 increases correspondingly, and as a result, the pressing force of the press roller 40 against the plate cylinder 20 increases and the print density increases. Becomes larger.

On the other hand, when the print density is set to be lower, the number of pulses supplied to the pulse motor 50 decreases, and as a result, the pressing force of the press roller 40 against the plate cylinder 20 decreases.

Based on the information stored in the RAM 220 as described above, the plate cylinder 20 and the press roller 40 are driven, and the paper feed mechanism 60 and the squeegee roller 36 are operated to perform printing (step 509).

In this case, the ink circulation differs between the first printing and after several sheets have been printed, and the use state of the stencil printing apparatus 1 is different. Therefore, during printing, the number of pulses supplied to the pulse motor 50 is appropriately controlled so as to satisfy the set print density while sequentially taking in information input from the use state detection mechanism 105.

Next, the CPU 220 determines whether or not the number of prints has reached the set number of prints. Here, when the number of prints reaches the set number of prints (step 510).
Yes), the printing process ends. On the other hand, if the number of prints has not reached the set number of prints (step 510)
No), the CPU 200 first identifies whether or not the print density has been changed by operating the print density setting key 5d of the operation panel 5, and if the print density has not been changed (No in step 511), the previous printing is performed. The next print processing is executed under the conditions (step 509).

On the other hand, if the print density has been changed (Yes at step 511), the print density setting information stored in the RAM 220 is changed to the changed print density setting information (step 512). Accordingly, in the subsequent printing process, when the press roller 40 is driven and pressed against the plate cylinder 20, the pulse generator 50 </ b> A
The number of pulses supplied to is changed in accordance with the changed print density setting information.

Thereafter, each time the print density is changed by operating the print density setting key 5d, the above processing is performed, and the number of pulses supplied to the pulse motor 50 is changed. Is changed.

That is, the printing density on the printing paper P is changed by changing the pressing force of the press roller 40 against the plate cylinder 20.

In this embodiment, as described above, not only the printing ink temperature but also the printing speed and the stencil
The printing process is performed at a desired print density in consideration of the usage state information. For this reason, fine density control according to the printing speed, the outside air temperature, and the use state of the stencil printing apparatus 1 is automatically performed.

In this embodiment, the printing ink temperature and the use state information of the stencil printing apparatus 1 are configured to be automatically input to the apparatus side by microcomputer control. Can be input by operating the ten key 5a.

In this embodiment, the driving device 400 for the press roller 40 is constituted by a cam and a link mechanism. However, a motor other than the plate cylinder driving motor 33 or a solenoid is used as a driving source. In this case, the hook lever 92 and the like are not required, and the configuration can be simplified.

Further, in this embodiment, a cylindrical press roller is used, but it is of course possible to apply the present invention to a deformed press roller proposed in Japanese Patent Application Laid-Open No. 62-73987.

[0076]

As is apparent from the above description, in the stencil printing apparatus according to the present invention, the pressing force of the press roller against the plate cylinder is automatically adjusted according to the temperature of the printing ink detected by the temperature detecting means such as a temperature sensor. Since the printing ink temperature is variably set, the printing density is automatically compensated for the printing ink temperature, and stencil printing with a desired density can be easily performed regardless of the change in the printing ink temperature.

[Brief description of the drawings]

FIG. 1 is an external view of a stencil printing apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing an operation panel of the stencil printing apparatus according to the present invention.

FIG. 3 is an overall schematic diagram showing an internal mechanism of the stencil printing apparatus according to the present invention.

FIG. 4 is a front view showing a detailed example of a press roller driving device used in the stencil printing apparatus according to the present invention.

FIG. 5 is a schematic diagram showing a state where a press roller is located at a press operation position.

FIG. 6 is a block diagram showing an electrical configuration of the stencil printing apparatus according to the present invention.

FIG. 7 is a flowchart showing the overall operation of the stencil printing apparatus according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 stencil printing machine 5 operation panel 5d print density setting key 20 plate cylinder 40 press roller S stencil sheet 104 temperature sensor 105 use state detecting mechanism 400 press roller driving device

Claims (1)

(57) [Claims] 1. A stencil printing apparatus for performing printing by pressing a printing paper against a stencil wrapped around an outer periphery of a cylindrical printing drum by a press roller to perform printing, wherein a temperature detecting means for detecting a temperature of a printing ink; Stencil printing apparatus, comprising: pressing force variable setting means for variably setting the pressing force of the press roller against the plate cylinder in accordance with the temperature of the printing ink detected by the detecting means.