JPH0576433B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a stencil printing apparatus, and more particularly to an ink supply system of a single-cylinder rotary stencil printing apparatus.

BACKGROUND TECHNOLOGY A mono-barrel rotary stencil printing device generally includes a cylindrical plate cylinder with a porous structure that rotates around its central axis and has a stencil printing paper wrapped around its outer circumferential surface, and a cylindrical plate cylinder that rotates around its central axis. An ink supply generally referred to as a squeegee roller, which is disposed in contact with the inner circumferential surface of the cylindrical plate cylinder and rotates around its own central axis to supply printing ink to the inner circumferential surface of the cylindrical plate cylinder. A stencil printing apparatus of this type is disclosed in, for example, Japanese Patent Laid-Open No. 55889/1989.

Problems to be Solved by the Invention When the above-mentioned stencil printing apparatus is not in use, it is left with the stencil printing paper wrapped around the outer circumferential surface of the cylindrical plate cylinder. Although covered with base paper, the inner peripheral surface of the cylindrical plate cylinder is exposed to the atmosphere, so if it is left for a long time, the cylindrical plate cylinder will become trapped inside the pores of its porous structure. The printing ink contained therein will harden, making it difficult for the printing ink to pass through the cylindrical plate cylinder, and there is a risk that printing will be impaired during reuse. When printing ink hardens and the flow of printing ink in the cylindrical plate cylinder deteriorates, the amount of printing ink supplied to the stencil printing paper attached to the outer circumferential surface of the cylindrical plate cylinder decreases, causing the stencil printing paper to deteriorate. The printing ink becomes less compatible with the paper, and in order to obtain printed matter with the appropriate density, it becomes necessary to perform several trial printings beforehand. This phenomenon becomes more pronounced the longer the stencil printing apparatus is left unused.

In view of the above-mentioned problems with conventional stencil printing devices, the present invention provides an improved stencil printing device that quickly resumes normal printing operation when restarted even if left unused for a long time. The purpose is to provide equipment.

Means for Solving the Problems According to the present invention, the above-mentioned object is to provide a cylindrical plate cylinder having a porous structure and having a stencil printing paper wrapped around its outer peripheral surface and rotating around its central axis; an ink supply roller disposed in contact with the inner circumferential surface of the cylindrical plate cylinder at its outer circumferential surface and rotating around its own central axis to supply printing ink to the inner circumferential surface of the cylindrical plate cylinder; In a stencil printing apparatus having a control means for controlling a contact pressure for bringing an ink supply roller into contact with the inner circumferential surface of the cylindrical plate cylinder, the control means is configured to control the control means when the stencil printing apparatus is turned on and when a test printing is performed. This is achieved by a stencil printing apparatus characterized in that it is configured to temporarily increase the contact pressure during at least one of the processes.

Effects and Effects of the Invention According to the configuration as described above, the contact pressure of the ink supply roller against the inner peripheral surface of the cylindrical plate cylinder is selectively increased by the control means, so that the cylindrical plate cylinder contains If the pressure applied to the printing ink in the direction from the inner circumferential surface of the drum toward the outer circumferential surface of the drum increases, and the cylindrical plate cylinder is rotated while this contact pressure increases, printing on the cylindrical plate cylinder The ink runs better throughout. Therefore, even if the printing ink contained in the cylindrical plate cylinder hardens and the printing ink in the cylindrical plate cylinder is difficult to pass through, the ink supply roller does not come into contact with the inner peripheral surface of the cylindrical plate cylinder as described above. By increasing the pressure, this problem is quickly resolved, and printed matter with the proper density can be obtained quickly without having to make many test prints.

The effect of increasing the contact pressure of the ink supply roller against the inner circumferential surface of the cylindrical plate cylinder, that is, the contact pressure increasing effect, occurs when the power is turned on when using the stencil printing device, and when printing with new stencil printing paper is started, that is, when printing starts with new stencil printing paper, It would be better if it was done at the time of printing. The contact pressure increasing effect when the power is turned on may be performed in a non-printing state, that is, without paper feeding and without operating the press roller, and the contact pressure increasing effect at the start of printing can be performed in a normal paper feeding state. In other words, the press roller may be pressed against the outer peripheral surface of the cylindrical plate cylinder while holding the printing paper between them. The effect of increasing the contact pressure under normal paper feeding conditions is so remarkable that normal stencil printing with proper density can be performed next time by just one trial printing using this printing paper.

Note that the amount of increase in contact pressure when the stencil printing device is powered on may be different from the amount of increase in contact pressure during plate placement, and the amount of increase in contact pressure during plate placement may be different from the amount of increase in contact pressure when the stencil printing device is turned on. It's nice and small compared to that.

Further, the driving means for driving the ink supply roller in a direction in which the contact pressure against the inner circumferential surface of the cylindrical plate cylinder increases may be configured such that its driving amount can be variably controlled. The contact pressure of the ink supply roller against the inner circumferential surface of the cylindrical plate cylinder is variably set depending on the amount of drive, thereby making it possible to adjust the printing density of ordinary printed matter.

EXAMPLES The present invention will now be described in detail by way of examples with reference to the accompanying drawings.

FIG. 1 shows one embodiment of a stencil printing apparatus according to the present invention. The stencil printing apparatus shown in FIG. 1 includes a plate-making device, and includes a cylindrical plate cylinder 2, a press roller 3, a paper feed table 4, a paper feed roller 5, and a paper feed roller 6. A paper device 7, a belt conveyor-type paper discharge device 8, a paper discharge table 9, a roll storage unit 10 that rotatably and replaceably accommodates a roll R of stencil printing paper, and a thermal plate-making device 11. , a base paper cutter 12 , a document mounting table 13 ,
It has a document discharge passage 14.

The cylindrical plate cylinder 2 is composed of, for example, a metal cylinder with a porous structure and a laminated body of screen mesh wrapped around the outer circumferential surface of the cylinder. It has a clamping means 15 for selectively locking, has a stencil printing paper S wrapped around its outer peripheral surface, and is rotated by an electric motor 20 around its own central axis in the counterclockwise direction as shown in the figure. It is becoming more and more common.

An ink supply device 19 having a squeegee roller 16, a doctor rod 17, and an ink supply pipe 18 is provided in the cylindrical plate cylinder 2, and the ink supply device 19 supplies the ink tube 21 according to the rotation of the cylindrical plate cylinder 2. The printing ink is supplied to the inner peripheral surface of the cylindrical plate cylinder 2.

The plate making device 11 includes a light source box 24 having a light source device 22 and a transparent glass light transmitting plate 23 attached to an upper opening thereof, and a presser box 24 fixedly arranged above the light source box 24 and facing the light transmitting plate 23. Board 2
5, the light source box 2 is moved between the release position where the light transmitting plate 22 is separated from the press plate 25 and the press position where the light transmitting plate 22 is pressed against the press plate 25.
A drive device 26 that reciprocates 4 in the vertical direction as shown in the figure.
It has

In the stencil printing apparatus constructed as described above, the stencil printing paper S of the roll R is transferred to the stencil printing apparatus 11.
The stencil sheet S for stencil printing is made into a plate by a thermosensitive method, and the stencil paper S thus made is fixed to the cylindrical plate cylinder 2 by the clamping means 15, and then wrapped around the outer circumferential surface of the cylindrical plate cylinder 2 and mounted. Then, in synchronization with the rotation of the cylindrical plate cylinder 2, the printing paper P is fed one by one from the paper feed table 4 toward the outer circumferential surface of the cylindrical plate cylinder 2, and is transferred to the cylindrical plate cylinder by the press roller 3. 2, the printing paper P is moved while being pressed against the stencil printing base paper S attached to the outer peripheral surface of the printing paper P. At this time, a printed image is formed on the printing paper P using printing ink, and then the printing paper is transferred to the paper ejection device 8. The paper is ejected onto the paper ejection table 9.

If a more detailed explanation of this stencil printing device equipped with a plate-making device is required, please refer to Japanese Patent Application No. 1983-96983, filed by the same applicant as the present applicant. sea bream.

FIGS. 2 and 3 show an enlarged view of the ink supply device, which is a main part of the stencil printing apparatus according to the present invention.

The ink supply device 19 has side plates 30 at both ends of the squeegee roller 16, and each of the side plates pivotally supports one end of a squeegee roller support lever 32 by a pivot 31. Each of the squeegee roller support levers 32 supports a squeegee roller support shaft 33 at its intermediate portion, and the squeegee roller support shaft 33 supports the squeegee roller 16 rotatably around its own central axis.

The side plate 30 supports the doctor rod 17,
The doctor rod 17 engages with elongated holes 35 provided in the side plate 30 at protrusions 34 provided at both ends thereof. A stay rod 36 passes through the protrusion 34, and one end of the stay rod 36 is screwed to the squeegee roller support shaft 33.
A compression coil spring 37 is provided between the protrusion 34 and the squeegee roller support shaft 33 so as to surround the stay rod 36. The compression coil spring 37 biases the doctor rod 17 in the direction of separating it from the squeegee roller 16, and by adjusting the screwing amount of the stay rod 36 into the squeegee roller support shaft 33, the squeegee roller 16 and the doctor rod 1 are separated.
The size of the ink metering gap 38 between the ink metering hole 7 and the ink metering gap 38 is determined.

The squeegee roller 16 contacts the inner circumferential surface of the cylindrical plate cylinder 2 with its outer circumferential surface, and rotates counterclockwise in FIG. 2 around its own central axis in synchronization with the rotation of the cylindrical plate cylinder 2. It is supposed to rotate. As the squeegee roller 16 rotates, printing ink A is supplied from the ink supply pipe 18 and is formed in the wedge-shaped space between the squeegee roller 16 and the doctor rod 17. It is deposited in a layer on the outer circumferential surface of the cylinder 16 with a thickness determined by the size of the gap 38, and is sent to the inner circumferential surface of the cylindrical plate cylinder 2.

An eccentric cam 40 for contact pressure adjustment is attached to the side plate 30 by a mounting screw 39. The eccentric cam 40 engages the squeegee roller support lever 32 on its outer peripheral surface and pushes the support lever clockwise in FIG. By adjusting the mounting phase, the pressure can be set to an appropriate value under normal printing conditions.

The side plate 30 has a long hole 41 and a rod 4 for increasing contact pressure.
I support 2. The contact pressure increasing rod 42 is spanned between the side plates 30 and engaged with the free end of the squeegee roller support lever 32. Further, a contact pressure increasing electric motor 43 is attached to the side plate 30.
An eccentric cam 45 is attached to the output shaft 44 of the electric motor. The eccentric cam 45 engages with the contact pressure increasing rod 42 and is rotationally driven by the electric motor 43 in the counterclockwise direction as viewed in FIG. 3, thereby pushing the contact pressure increasing rod 42 downward. As seen in FIG. 2, the squeegee roller support lever 32 is driven in a counterclockwise direction.

Under normal conditions, the position of the squeegee roller support lever 32 is determined by the eccentric cam 40, and the contact pressure of the squeegee roller 16 against the inner peripheral surface of the cylindrical plate cylinder 2 is maintained at a contact pressure suitable for normal printing. The rotational position of the eccentric cam 45 is adjusted so that the contact pressure increasing motor 4 is tilted so that the contact pressure increasing rod 42 does not apply pressure to the squeegee roller support lever 32.
On the other hand, when the power is turned on or when the contact pressure increases during printing, the eccentric cam 45 is rotated by the electric motor 43 in the counterclockwise direction as seen in FIG. As a result, the contact pressure increasing rod 42 is pushed downward in the figure, and the contact pressure increasing rod 42 drives the squeegee roller support lever 32 clockwise as viewed in FIG. 2. As a result, the contact pressure of the squeegee roller 16 against the inner circumferential surface of the cylindrical plate cylinder 2 increases in accordance with the amount of rotation of the eccentric cam 45 compared to under the above-mentioned normal state.

The operation of the contact pressure increasing electric motor 43 is controlled by a control system as shown in FIG. 4, for example.

This control system has an electric control device 50 that includes a microcomputer, and this control device controls all the plate making and printing operations in addition to controlling the energization of the contact pressure increasing electric motor 43. ing. The control device 50 receives information regarding opening/closing from a power switch 51, information regarding opening/closing from a first print switch 52, information regarding opening/closing from a print start switch 53, and information regarding the number of prints from a print number setting device 54. Various types of information are given from various switches and sensors 55 for plate-making and printing operations, and the electric motor 20 for driving the plate cylinder is activated according to this information.
The contact pressure increasing motor 43 and other various motors and actuators 56 for plate making and printing (not shown) are controlled.

Regarding contact pressure increase control, the control device 50
When the power switch 51 is closed and the stencil printing device is powered on, the contact pressure increasing electric motor 43 is turned on.
outputs a signal to rotate by a predetermined amount in the direction of increasing contact pressure and a signal to rotate the electric motor 20 for driving the plate cylinder by a predetermined number of rotations, and when the first print switch 52 is closed, plate making is performed. After a new stencil printing base paper S is wound around the outer circumferential surface of the cylindrical plate cylinder 2, a signal is generated to drive the contact pressure increasing electric motor 43 by a predetermined amount in the direction of increasing the contact pressure, and the cylindrical plate cylinder 2 rotates once. It outputs a signal to rotate the plate cylinder driving electric motor 20 by a predetermined number of rotations so as to rotate it, and at the same time outputs a control signal to various printing electric motors and actuator 56 so that printing is performed on one sheet of printing paper. I'm starting to do that.

Therefore, when the power of the stencil printing apparatus is turned on, the press roller 3 is in the retracted position as shown by the solid line in FIG. The contact pressure against the inner peripheral surface of the plate cylinder 2 is increased, and in this state the cylindrical plate cylinder 2 rotates a predetermined number of times. As a result, the printing ink contained in the cylindrical plate cylinder 2, which has hardened when the stencil printing apparatus is left unused, is discharged onto the outer circumferential surface of the cylindrical plate cylinder 2. When the stencil printing paper S for the previous printing, which is attached to the outer peripheral surface of the cylinder 2, is removed, it adheres to the stencil printing paper S and is removed.

When the first print switch 52 is closed, that is, at the time of plate making and printing, the cylindrical plate cylinder 2 of the squeegee roller 16 is activated by the contact pressure increasing electric motor 43 when a test print is made on a sheet of printing paper P.
The contact pressure against the inner circumferential surface of the stencil sheet S is increased, and as a result, the printing ink is reliably adapted to the new stencil printing base paper S by making only one test print. As a result, printing at the appropriate density can be started immediately after this without wasting printing paper or time.

Note that when the cylindrical plate cylinder 2 rotates a predetermined number of times when the power is turned on and during first printing, the contact pressure increasing motor 43 is driven in the reverse direction to eliminate the contact pressure increasing effect, and after this, the squeegee roller 1
The contact pressure against the inner circumferential surface of the cylindrical plate cylinder 2 of 6 is maintained at an appropriate value under normal printing conditions determined by the eccentric cam 40.

As mentioned above, the action of increasing the contact pressure of the squeegee roller 16 against the inner circumferential surface of the cylindrical plate cylinder 2 occurs when the stencil printing apparatus is left unused for a predetermined period of time, for example, 10 hours or more. Further, the contact pressure increase amount or the rotation speed of the cylindrical plate cylinder 2 in the contact pressure increase state may be variably controlled depending on the continuous standing time. You can leave it there.

The contact pressure control means of the stencil printing apparatus according to the present invention is not limited to an electric motor, but may be a solenoid device, a fluid pressure actuator, or other actuator.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto, and various embodiments are possible within the scope of the present invention. It will be clear to those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing one embodiment of a stencil printing apparatus according to the present invention, FIG. Figure 3 shows the line in Figure 2 -
FIG. 4 is a block diagram showing a control system for a stencil printing apparatus according to the present invention. 2... Cylindrical plate cylinder, 3... Press roller, 4... Paper feed stand, 5... Paper feed roller, 6... Paper feed roller, 7... Paper feed device, 8... Paper discharge device, 9... Paper discharge base, 10... Roll storage unit, 11... plate making device, 12... base paper cutter,
13...Document placement table, 14...Document ejection path, 15...
Clamping means, 16... Squeegee roller, 17...
Doctor rod, 18... Ink supply pipe, 19...
Ink supply device, 20... Electric motor, 21... Ink tube, 22... Light source device, 23... Light transmission plate, 24
...Light source box, 25...Press plate, 26...Drive device, 30...Side plate, 31...Pivot, 32...Squeegee roller support lever, 33...Squeegee roller support shaft, 34...Protrusion part, 35...Long hole, 36...Stay rod, 37... Compression coil spring, 38... Gap, 39
...Mounting screw, 40...Eccentric cam for adjusting contact pressure, 41
...Elongated hole, 42...Rod for increasing contact pressure, 43...Electric motor for increasing contact pressure, 44...Output shaft, 45...Eccentric cam for increasing contact pressure, 50...Control device, 51...Power switch, 52...First print switch , 53
...Print start switch, 54...Print number setting device, 55...Various switches and sensors, 56...Various motors and actuators for plate making and printing.

Claims (1)

[Scope of Claims] 1. A cylindrical plate cylinder with a porous structure that rotates around its own central axis and has a stencil printing base paper wrapped around it on its outer circumferential surface, and an inner circumferential surface of the cylindrical plate cylinder on its outer circumferential surface. an ink supply roller that is arranged in contact with and rotates around its own central axis to supply printing ink to the inner circumferential surface of the cylindrical plate cylinder; In the stencil printing apparatus, the control means temporarily controls the contact pressure at least one of when the stencil printing apparatus is turned on and when making a test print. A stencil printing device characterized in that the stencil printing device is configured to increase the number of digits. 2. In the stencil printing apparatus according to claim 1, the control means temporarily increases the contact pressure when the stencil printing apparatus is continuously unused for a predetermined period of time or more. A stencil printing device characterized in that the stencil printing device is used later when the stencil printing device is turned on or when a test printing is performed.