JPH09169154A - Screen printing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screen printing machine capable of economically using stencil paper. SOLUTION: Cams 54, 54' having cam surfaces of which the number corresponds to the changeover kinds of pressing length are provided to a shaft 60 movable in its axial longitudinal direction as a press means pressing the stencil paper wound around a printing drum by predetermined pressing length through printing paper and the shaft 60 is moved in the axial longitudinal direction thereof to rapidly change over the pressing length of the printing paper. Data for changeover is based on the size of printing paper and the cutting length of the stencil paper is set on the basis of the data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing machine having a plate making function.

[0002]

2. Description of the Related Art A roll-shaped heat-sensitive stencil sheet is made into a plate, which is cut and automatically wound around the outer peripheral surface of a printing drum, and the fed printing paper is pressed onto the outer peripheral surface of the printing drum. A stencil printing apparatus is known which performs printing by pressing with a roller. In this stencil printing apparatus, for example, a plate-making unit for making a plate on a roll-shaped heat-sensitive stencil sheet, a cutting unit for cutting the heat-sensitive stencil sheet, a base paper feeding unit for conveying the heat-sensitive stencil sheet, the heat-sensitive stencil sheet. A print drum that wraps around its outer peripheral surface to supply ink, and a print sheet storage unit that can store print sheets of different sizes,
A paper feed unit that feeds the print paper stored in the print paper storage unit toward the print drum unit, and the print paper sent by the paper feed unit in a printing unit by a roller-shaped rotating body. The outer peripheral surface of the printing drum is provided with a pressing unit for pressing and releasing the pressure, and the cutting length of the base paper by the cutting unit and the pressing length of the printing paper by the pressing unit are the size of the original document to be used and the printing. It is always fixed to a fixed size regardless of the size of the paper.

On the other hand, when printing a small number of copies using such a stencil printing machine, the cost of the base paper has the greatest effect on the printing cost per sheet. Therefore, the length of the base paper used for one plate-making is required to be as short as possible. However, in the conventional stencil printing machine, even when performing small-sized plate making printing such as A6 size and A4 size, which is a postcard size, use a large size stencil such as A3 size based on the specifications of the stencil printing machine. However, it has a problem that the base paper is very wasteful.

There are the following two known techniques as means for solving such a problem. . The size of the printing paper stored in the printing paper storage is detected by the size detecting means, and the cutting timing of the heat-sensitive stencil sheet is set by the control means based on this detection information, and the heat-sensitive stencil sheet is cut according to the size of the printing sheet. At the same time, the pressing length of the printing paper by the pressing means for pressing and releasing the printing paper on the outer peripheral surface of the printing drum by the roller-shaped rotating body at the printing pressure part is also switched by the switching means (special feature). (See Japanese Unexamined Patent Publication No. 64-24783).

In the technique disclosed in this publication, when the size of the printing paper set in the stencil printing machine changes, the cutting size of the base paper is automatically switched according to the size of the set printing paper, and the pressing is performed. Since the pressing length of the printing paper by the means is also switched, and the unused portion of the base paper is greatly reduced, the printing cost per printing paper becomes low.

[0006] A stencil printing apparatus that selects and uses two types of printing drums having different printing areas, and a detection unit detects which of the two types of printing drums is mounted on the stencil printing apparatus. Based on the detected information, the control means sets the cutting timing of the heat-sensitive stencil sheet, cuts the heat-sensitive stencil sheet according to the size of the print sheet, and prints the print sheet with the roller-like rotary member at the printing pressure section. A stencil printing apparatus in which the pressing length of the printing paper by the pressing means for pressing and releasing the outer peripheral surface of the drum is also switched by the switching means (Japanese Patent Laid-Open No. Sho 64).
-18683 gazette). In this technique as well, as in the technique of (1), the unused portion of the base paper is significantly reduced, so that the printing cost per printing sheet can be low.

When comparing these techniques, in the above technique, the information for switching the cutting size of the base paper and the pressing length of the printing paper by the pressing means is based on the size of the printing paper. This technique is different in that it is based on the size of the printing drum set in the stencil printing machine.

Further, in any of these techniques, control of pressing and releasing the press of the printing paper on the outer peripheral surface of the print drum is performed by the roller-shaped rotating body at the printing portion on the outer peripheral surface of the print drum. Although it is common in that the cam has a pressing means using a cam, in the technology of, the cam forming the pressing means is composed of two cams that are coaxially overlapped and provided.
The total length of the cam surfaces of these cams is changed to change the pressing length of the printing paper, and the switching means for this switching rotates one cam with respect to the other cam. According to the technique of the shift means, the cam forming the pressing means is an integral cam sharing different cam surfaces, and the length of the cam surface is switched by relative rotation of the cams. The switching means for this switching is different in that it is composed of a screw and nut combination mechanism driven by a motor.

[0009]

In the above technique, when the size of the printing paper is changed from A3 to A6, for example, the shift amount due to the rotation of the cam increases, so that the time required for this shift also increases. For this reason, the so-called first print time from the start of plate making until the first print sheet comes out to the delivery tray becomes long. The above-described technique is premised on having two types of printing drums having different printing areas, and thus is expensive, and it takes time to replace the drums, which is complicated.

An object of the present invention is to provide a stencil printing machine which can economically use a base paper without causing these problems.

[0011]

The present invention provides (1). A plate-making section for making a plate on a roll-shaped heat-sensitive stencil sheet, a cutting section for cutting the heat-sensitive stencil sheet, a base paper feeding section for conveying the heat-sensitive stencil sheet, and an ink by winding the heat-sensitive stencil sheet around its outer peripheral surface. Supply a printing drum,
A printing paper storage unit that can store printing paper of different sizes, a paper feed unit that feeds the printing paper stored in the printing paper storage unit toward the printing drum unit, and a paper feeding unit Detecting the size of the printing paper stored in the printing paper storage unit, and a pressing unit that presses the roller-shaped rotator against the outer peripheral surface of the printing drum by the printing unit with the sent printing paper and the pressing release. The size detecting means, the control means for setting at least the cutting timing of the heat sensitive stencil sheet in the cutting section, and the switching means for switching the pressing length of the printing paper by the pressing means in the printing section. In the stencil printing apparatus configured to cut the heat-sensitive stencil sheet according to the size of the printing sheet and set the pressing length of the printing sheet, the pressing unit is There is a cam for controlling the pressing and the pressing release by the roller-shaped rotating body, and the cam has as many types of cam surfaces as there are types of the pressing length of the printing paper, and the detection information of the size detecting means is provided. Based on this, the pressing length of the printing paper is switched by switching the cutting length of the heat-sensitive stencil sheet and the cam surface by the switching means (claim 1).

(2). (1) In the stencil printing machine according to (1), the cam is integrally provided with a rotary shaft that is rotationally driven in synchronization with the printing drum, and the cam surfaces are arranged in the axial longitudinal direction of the rotary shaft. (Claim 2).

(3). In the stencil printing machine according to (1) or (2), the switching unit includes a switching position setting unit that restricts a movement of the rotary shaft in the axial longitudinal direction to a position where the cam surface is switched, and the switching position setting unit. The holding means holds the rotary shaft at the position set by the position setting means (claim 3).

(4). In the stencil printing machine according to (2) or (3), the switching unit biases the rotary shaft in a longitudinal direction of the rotary shaft, and the rotary shaft against the biasing force of the biasing unit. And a pushing means for pushing (claim 4).

(5). In the stencil printing machine according to (4), the movement of the rotary shaft by the switching means is performed manually or by a drive device. When the drive device is used, the pushing means is operated by the output of the control means. (Claim 5).

(6). (1), (2), (3), (4)
Alternatively, in the stencil printing machine according to (5), the number of types of the cam surface and the type of pressing length of the printing paper is set to 2 (claim 6). In this way, by setting the number of types of cam surfaces and types of pressing length of printing paper to two, it is possible to perform a switching operation of the rotary shaft by a single reciprocating operation based on the original position.

(7). In the stencil printing machine according to (4), the pushing means has a swing arm that pushes the rotary shaft in response to the swing, and a solenoid that swings the swing arm (claim 9). 7).

[0018]

Embodiments of the present invention will be described below. one. Stencil printing apparatus suitable for carrying out the invention (1) Overall outline of stencil printing apparatus An overall outline of a stencil printing apparatus to which the present invention is applied is shown in FIG. In FIG. 1, the printing drum 1 has a cylindrical body having a porous structure, and a mesh screen is wound around the outer circumference of the cylindrical body. A master clamper 12 which is rotatable in parallel with the axis of the printing drum 1 is provided on the outer peripheral portion of the printing drum 1. The master clamper 12 is opened and closed at a predetermined position by transmitting a driving force by an opening / closing device (not shown). One end of a master 2, which is a heat-sensitive stencil sheet, is held by the master clamper 12, and the other end side is wound around the outer peripheral surface of the plate cylinder 1.

The master 2 is perforated by the plate making section 19 located on the right side of the printing drum 1 in FIG. 1 based on the information of the original, and is conveyed by the base paper feeding section to reach the printing drum 1 and the printing drum 1 is conveyed. It is wrapped around the outer peripheral surface. The master 2 is cut to the required length. The master roll 10 wound in a roll shape is rotatably held on the plate making unit 19. The master 2 unrolled from the master roll 10 is punched and perforated by being conveyed while being pressed by the platen roller 9 against the heating element portion of the thermal head 17. Here, the thermal head 17 selectively heats the heating element portion based on an image signal sent from a scanner (not shown) to perform perforation plate making. The plate-made master 2 is cut by a cutter 4 as a cutting unit, and is conveyed toward a clamper 12 of the printing drum 1 by a plate feeding roller 5 as a raw paper feeding unit. Eventually, the master 2 reaches the clamper 12, and the clamper 12 catches and clamps the tip of the master 2.

After the clamper 12 clamps the tip of the master 2, the master 2 is wound around the outer circumference of the print drum 1 by the rotation of the print drum 1. During this time, punching by the thermal head 17 is performed if necessary. Master 2
Is controlled by the platen roller drive pulse motor 6 that drives the platen roller 9, and if the required fixed amount of feed is completed based on a command from the control device (described later with reference to FIG. 5), the cutter 4 is driven. The cutter drive motor 7 for driving the eccentric cam rotates the eccentric cam 8 to move the cutter 4 to cut the master 2. In this way, the printing drum 1 completely winds the master 2 around the outer periphery thereof, thereby completing the plate making and plate supply.

A plate discharging device 18 is provided on the left side of the printing drum 1 in FIG. After printing, print drum 1
The used master 2 wound around the printing drum 1 is
It is peeled off and stored in the plate discharging device 18.

The printing drum 1 is rotated in the clockwise direction by a driving device (not shown). Inside the print drum 1,
An ink roller 13 that rotates in synchronization with the same direction as the printing drum 1 and a doctor roller 15 are provided with a slight clearance from the outer peripheral surface of the ink roller 13. A wedge-shaped facing space formed between the ink roller 13 and the doctor roller 15 forms an ink reservoir 16. To the ink reservoir 16, ink 1 is fed from the hole of the shaft pipe 11.
4 are supplied. The ink 14 in the ink reservoir 16 is supplied to the outer peripheral surface of the ink roller 13 by the rotation of the ink roller 13 and the doctor roller 15. Further, the ink supplied to the outer peripheral surface of the ink roller 13 is supplied to the inner peripheral surface of the print drum 1 because there is a slight gap between the inner peripheral surface of the print drum 1 and the outer peripheral surface of the ink roller 13. .

Below the printing drum 1, an ink roller 1 is provided.
An impression cylinder 20 formed of a roller-shaped rotating body is located opposite to the pressure roller 3. The impression cylinder 20 presses the printing paper 3 superposed on the master 2 on the printing drum 1 onto the printing drum 1 at a printing portion which is a position on the outer peripheral surface of the printing drum 1 facing the ink roller 13. , A roller-shaped rotating body. A so-called press roller may be used instead of the impression cylinder 20. In the following example, the case of the impression cylinder 20 will be described.

The impression cylinder 20 is a clamper 12 on the printing drum 1.
In order to avoid a collision with, a part of the outer periphery of the impression cylinder 20 is configured with a flat portion, and has a D shape when viewed in the axial direction. A gripper 21 for holding the leading end of the printing paper 3 is provided on the flat portion so as to be opened and closed by turning. The gripper 21 opens at a predetermined timing by a cam (not shown), grips the front end of the printing paper 3, and then closes to hold the printing paper 3 on the impression cylinder 20. When printing is completed, the outer circumference of the impression cylinder 20 is stopped. It is opened again at the paper ejection pawl 29 provided in the vicinity of the portion, and the paper ejection conveyance device 35 is opened via the paper ejection pawl 29.
The leading end of the printing paper 3 is opened in order to feed the leading end of the printing paper 3 to the sheet.

The pressure drum 20 presses the printing paper 3 in accordance with the size of the printing paper 3, and the printing drum 1
One end of the fulcrum shaft 24 is supported by a fulcrum shaft 24 as a means for controlling the timing of pressing and separating the impression cylinder 20 so that the printing paper is not pressed at a portion where the printing paper 3 is not present. The cams 54, 54 which are swingable about the center of the swing drum 25, and rotatably support the impression cylinder 20 on the free end side of the swing arm 25, and rotate the swing arm 25 in synchronization with the printing drum 1. '(Described later with reference to FIGS. 2 and 4) to swing the impression cylinder 20 against the printing drum 1 at a predetermined timing or separate it from the printing drum 1 only when necessary.
Is pressed.

The means for pressing the impression cylinder 20 against the printing paper at the printing section and separating them from each other is called pressing means.
The pressing means is composed of a swing arm 25, a pressing spring 26 which is an elastic spring, the cam, the impression cylinder 20, and the like. The swing arm 25 and the pressing spring 2
6. Regarding the cam, in addition to that shown in FIG. 1, the same member is provided on the opposite side of the impression cylinder 20 that penetrates the plane of FIG. Further, the impression cylinder 20 is not pressed by the printing drum 1 when a conveyance error occurs, and is released by a printing pressure release device (not shown). The cams 54, 54 ′ have a number of cam surfaces corresponding to the type of pressing length of the printing paper by the impression cylinder 20. The cam surface is switched according to the size of the printing paper. This switching means will be described later.

In FIG. 1, a paper ejection claw 29 for peeling the printing paper 3 after printing (after application of ink) from the impression cylinder 20 and a paper 3 which has been peeled off near the lower left outer peripheral surface of the printing drum 1. Paper discharge transport device 35 for transporting paper, and paper discharge transport device 35
A paper discharge table 36 for accumulating the printing paper 3 conveyed by is provided.

In FIG. 1, on the lower right side of the printing drum 1, there is provided a printing paper storage unit consisting of an elevator type paper feed tray 31 capable of storing printing papers of different sizes. A sensor 4 as a size detecting means for detecting the size of the printing paper stored in the paper feeding table 31.
0, a sensor 41 is provided. The sensor 40 is arranged at a position where the front end side of the printing paper can be detected, and the sensor 41 is arranged behind the sensor 40 in the transport direction with a predetermined interval. As a result, when the sensor 40 alone detects the presence of the printing paper,
The size of the stored printing paper can be identified depending on the case where the presence of the printing paper is detected. This paper feed table 31
Is a stack of printing papers 3 loaded by a driving device (not shown).
The uppermost part of the above is always lifted while being held by the calling roller 30 so as to be applied with an appropriate pressing force that enables conveyance.

The paper feeding unit has a rotatably supported paper feeding roller 32 and a calling roller 30, and these rollers are connected by an endless belt (not shown). Below the paper feed roller 32, a separation roller 34, which prevents double feeding of printing paper, is in pressure contact. Further, a pair of feed rollers 33, which are rotatably supported, and a pair of guide plates 38, which guide the print sheet 3 to the feed roller nip portion, are provided on the front side of the print sheet conveyance direction.

The paper feed roller 32 is rotated clockwise by a cam (not shown) that rotates in synchronization with the printing drum 1, a fan-shaped gear having a cam follower engaging with the cam, and a paper feed roller gear incorporating a one-way clutch. To be rotated. Similarly, the feed roller 33 has a cam (not shown) that rotates in synchronization with the print drum 1, a fan-shaped gear having a cam follower engaged with the cam, a feed roller gear having a one-way clutch incorporated therein, and the like. It is rotated clockwise. The feeding speed of the printing paper by the feed roller 33 is set to be the same as the peripheral speed of the printing drum 1.

(2) Printing Paper Conveying Procedure The printing paper 3 delivered by the rotation of the paper feeding roller 32 and the calling roller 30 is the paper feeding roller 32 and the separating roller 34.
Double feeding is prevented at a portion, and only the uppermost one sheet is fed to the feed roller 33. When the leading edge of the printing paper 3 collides with the nip portion between the feed rollers 33 and is fed from the rear side, a predetermined amount of sag is formed upward. At the time when this sagging slack is formed, the feed roller 32 and the calling roller 30 stop rotating.

After that, the feed roller 33 is rotated at a predetermined timing by which the master 2 on the printing drum 1 and the printing paper 3 can be matched with each other by the cam to eliminate the sagging of the printing paper 3. Further, the printing paper 3 is carried toward the impression cylinder 20 while the paper feed roller 32 and the calling roller 30 which are incorporated with a one-way clutch and are rotatable in the paper carrying direction are also driven and rotated by the carrying of the printing paper 3. . In accordance with this timing, the gripper 21 in the impression cylinder 20 is opened, after gripping the printing paper 3, the gripper 21 is closed, and the printing cylinder 3 is held by the impression cylinder 20.
0 rotates, and the printing paper 3 is fed to the nip portion between the printing drum 1 and the impression cylinder 20, that is, the printing portion.

At this time, the impression cylinder 20 is pressed by the force of the elastic pressing spring 26, and the printing paper 3 is pressed against the outer peripheral surface of the printing drum 1. At the time of this pressing, the ink roller 13 transfers the ink that has passed through the perforated portion of the master 2 attached to the outer peripheral surface of the printing drum 1 to perform printing. The printing paper 3 on which the ink has been transferred is further rotated by the impression cylinder 20 so that the gripper jaws 21 are opened in front of the paper ejection pawls 29 and are peeled off by the paper ejection pawls 29. The sheet is conveyed to the sheet 36, stacked on the sheet discharge tray 36, and printing is completed.

(3) Master cutting length setting means, printing paper pressing length switching means This will be described with reference to FIGS. 1 to 6. The impression cylinder 20 is integrally formed with the central shaft 23 and the central shaft 23 '. The central shafts 23, 23 'project to both sides in the axial direction of the impression cylinder 20, and the projecting parts are supported at intermediate positions of the swing arms 25, 25' via bearings 50, 50 '. . As a result, the impression cylinder 20 moves the swing arms 25, 25 '.
It is rotatable with respect to.

The fulcrum shafts 24, 24 'are mounted on the respective one ends of the swing arms 25, 25' via bearings 51, 51 '. The end of the fulcrum shaft 24 is fixed to the front plate 52. The fulcrum shaft 24 'penetrates the swing arm 25' and the bearing 5
It penetrates through the rear side plate 52 'through 5. With this configuration, the impression cylinder 20 is supported by the swing arms 25 and 25 'swinging around the fulcrum shafts 24 and 24'.
Thus, the reason why the impression cylinder 20 is supported by the pair of swing arms 25 and 25 'is to uniformly press the impression cylinder 20 against the printing drum 1 in the axial direction.

The fulcrum shafts 24 of the swing arms 25, 25 ',
On the side opposite to 24 ', that is, on the free end side, one end sides of pressing springs 26, 26' made of elastic springs are hooked, and the other end side is hooked on a stationary member. Therefore, due to the elasticity of these pressing springs 26, 26 ', the swinging arms 25, 25' are rotated about the fulcrum shafts 24, 24 'in FIG. Rotational force is applied in the direction to be made. In other words, the pressing springs 26, 26 ′ generate the rotational moment in the direction of pressing the impression cylinder 20 against the printing drum 1 by the swing arms 25, 2.
5'acts.

A fulcrum shaft 24 'penetrating the swing arm 25'
A gear 57 is integrally attached to one end side of the gear 57, and the gear 57 is meshed with a gear 58 integrally attached to the central shaft 23 '. In addition, the fulcrum shaft 24 'penetrating the rear side plate 52' has a support frame 80 provided outside the rear side plate 52 '.
Is supported by a bearing 55 '. These bearings 55, 5
A pulley 56 is fixed to the fulcrum shaft 24 'between the 5'and the belt wound around the pulley 56 and a drive source (not shown) causes the impression cylinder 20 to rotate at the same linear velocity as the printing drum 1. It is supposed to be done.

The impression cylinder 20 must be pressed against the printing drum 1 every time printing is performed, and the swing arms 25 and 25 'must be repeatedly swung about the fulcrum shafts 24 and 24'. Therefore, cam followers 53, 53 'are pivotally attached to the respective free ends of the swing arms 25, 25', and these cam followers 53, 53 'are attached to the cam surfaces of the cams 54, 54' by pressing springs 26, 26 '. The contact is made by elasticity.

Both the cams 54 and 54 'are fixed to the shaft 60. The cam 54 has an integral structure including cam plates 54a and 54b having different cam surfaces.
In, the cam plate 54b is located to the right of the cam plate 54a. Similarly, a cam plate 54b 'is provided on the right side of the cam plate 54a'.
Is located. The cam plate 54a and the cam plate 54a 'have the same size and shape. Also, the cam plate 54b and the cam plate 5
4b 'has the same size and shape. Cam plate 54a,
The cam plate 54a 'is suitable for the pressing control of the impression cylinder 20 on the printing paper up to A4 size. Also, the cam plates 54b, 54
b'is suitable for the pressure control of the impression cylinder 20 against the printing paper of A3 size to A3 size.

A shaft 60 integrally formed with these cams 54, 54 'has a bearing 65 with respect to the front plate 52,
Further, the rear side plate 52 'is rotatable via a bearing 65', and
It is slidably supported in the longitudinal direction of the shaft. A gear 66 is fixed to a portion of the shaft 60 protruding from the bearing 65 '. A gear 66 'is meshed with the gear 66, and the gear 66' is connected to a drive system (not shown).
The shaft 60 is connected to the printing drum 1 by the power transmission from this drive system.
It is designed to rotate in synchronism with the rotation of.

The shaft 60 is slidable in the longitudinal direction of the shaft as described above, and the cam followers 53, 5 are moved in response to the sliding.
3 ', the cam plates 54a and 54a' are in contact with each other, and the cam followers 53 and 53 'are cam plates 54b and 54a.
The state in which 54b 'abuts can be switched. FIG. 2 shows a state where the cam plates 54a and 54a 'are in contact with the cam followers 53 and 53'. Therefore, the movement stroke of the shaft 60 is equal to the distance between the cam plates 54a and 54b, and the cam plates 54a, 54b
To switch between a'and the cam plates 54b, 54b ', it is sufficient to move with this stroke. In order to ensure the rotation of the shaft 60 even when the shaft 60 slides, the thickness of the gear 66 is
The size is set to correspond to the moving stroke.

As shown in FIGS. 2 and 3, the bearing 6 of the shaft 60
A bearing cover 67 is attached to the shaft end projecting from No. 5 via a bearing 68. The bearing cover 68 rotatably supports the shaft 60, and can abut the shaft end portion of the shaft 60 to push the shaft 60 in the axial direction. One end of the swing arm 63 is pivotally attached to the bearing cover 67 by a shaft 70. An intermediate portion of the swing arm 63 is pivotally attached to a support member 81 integrated with the front side plate 52 via a shaft 64. The other end of the swing arm 63 is pivotally attached to a plunger of a solenoid 82 fixed to a stationary member. Bearing 65
An extensible spring 69 is provided between the shaft and the bearing 68 so as to wind the shaft 60 loosely. A stopper 71 is fixed on the shaft 60 between the front plate 52 and the swing arm 25.

When the solenoid 82 is turned off, the elasticity of the spring 69 urges the shaft 60 to the left in FIG. The movement of the shaft 60 due to this bias is prevented by the stopper 71.
Abut the bearing 65 or are blocked by the bearing cover 67. When the solenoid 82 is turned on, the shaft 60
2 to the right against the elasticity of the spring 69, and the cam plates 54a, 54a 'move to the cam followers 53, 5'.
3'is brought into contact with the positional relationship.

On the other hand, when the solenoid 82 is turned off, the force of the spring 69 allows the plunger of the solenoid 82 to be in a protruding state. Therefore, when the solenoid 82 is turned off, the shaft 60 moves leftward from the position shown in FIG. 2 and stops at the position where the stopper 71 contacts the bearing 65. At this stop position, the cam plates 54b and 54b 'come into contact with the cam followers 53 and 53'. Therefore, in this configuration, the cam followers 53 and 53 'are attached to the cam plates 54a and 54a in accordance with the on / off control of the solenoid 82.
It is possible to switch between contacting a'or contacting the cam plates 54b, 54b '.

As described above, the length of the master 2 can be cut according to the length of the printing paper by controlling the start and stop of the platen roller driving pulse motor 6 and the cutter driving motor 7, and the solenoid 82 can be cut. The pressing length of the printing paper can be switched by the on / off control. The control of starting and stopping the platen roller drive pulse motor 6 and the cutter drive motor 7 and the on / off control of the solenoid 82 are performed by inputting the outputs from the optical sensors 40 and 41 as shown in FIG. This is done by an instruction based on a predetermined program of the means 84. Therefore, the optical sensor 4 for detecting the size of the printing paper which is the basis for such control
The arrangement of 0 and 41 will be described.

(4) Arrangement of Optical Sensors on the Paper Feeding Table In FIG. 6, the printing paper is stored on the paper feeding base 31 by aligning the left end of the paper feeding base 31 with the end of the printing paper. It is assumed that the printing paper is housed on the basis of what is called a central standard in which the center of the printing paper is aligned with the center of the base 31, and the direction in which the printing paper is conveyed is indicated by a white arrow. Printing papers of A6 size to A3 size can be placed on the paper feed table 31. In the figure, “A6 portrait” means that A6 size printing paper is arranged with its longitudinal direction and conveyance direction aligned, and “A4 landscape” means that A4 size printing paper is its transverse direction. This is a case where they are arranged so as to match the transport direction. According to such a display direction, “A6
"Vertical", "A4 landscape", "B5 portrait", "A4 landscape", "B4"
Six types of printing paper types, “vertical” and “A3 vertical”, and arrangement modes are possible. In this example, the optical sensor 40 is provided near the left end of the paper feed table 31. Further, the optical sensor 41 is arranged outside the position of A4h, which is the lateral dimension of A4, from the left end of the paper feed tray 31, and inside the position of B5v, which is the vertical dimension of B5 from the left end of the paper feed tray 31. doing.

By arranging the optical sensors in this way, no matter whether the printing paper is "A6 portrait" or "A4 landscape", when only the optical sensor 40 detects the presence of the print paper, "A4 landscape" is displayed. It is determined that the optical sensor 40 and the optical sensor 41 are in any of the cases of "B5 portrait", "A4 portrait", "B4 portrait", and "A3 portrait". When both of them detect the presence of printing paper, it is determined that they are in the "A3 portrait" storage state, and the cutting length of the master and the pressing length of the impression cylinder can be controlled. Thus, the cutting length of the master and the pressing length of the impression cylinder are controlled in two stages. Each of the cams 54, 54 'has two cam plates 54a,
The structure having 54b and the cam plates 54a 'and 54b' corresponds to the division into these two stages.

That is, the cam plates 54a, 54a 'have cam surfaces that allow a uniform pressing length when the printing paper is "A6 portrait" or "A4 landscape", and the cam plates 54b, 5a.
4b 'has printing paper of "B5 portrait", "A4 portrait", "B4 portrait"
In the case of "vertical" and "A3 vertical", it has a cam surface that allows a uniform pressing length.

In this example, the cutting length of the master and the pressing length of the impression cylinder are divided into two stages. However, by increasing the number of locations of the optical sensor and providing a cam corresponding thereto, the size of the printing paper can be made more detailed. It is possible to set the cutting length of the master or the pressing length of the impression cylinder according to the above.

(5) Relationship between cutting length of master and pressing length of impression cylinder FIGS. 7A and 7B show a state in which a part of the printing drum 1 is partially developed in the winding direction of printing paper. These Figure 7
In (a) and (b), the cylindrical printing drum 1 is made of a thin metal plate, and has a specific area of 0.
Countless small holes with a diameter of 5 mm are made. A mesh screen 27 is provided so as to cover the opening, and the master 2 is mounted on the mesh screen 27. The tip of the master 2 is held by the clamper 12. In this example, the opening length C, which is the length of the opening of the printing drum 1, is about 430 mm.
It is.

FIG. 7A illustrates the relationship between the cutting length of the master and the pressing length of the impression cylinder, which is executed when the printing paper is stored in "A3 portrait". In this case, the plate making length A of the master 2 is 410 mm. The pressing length B, which is the size of the section where the impression cylinder 20 presses the printing paper, is set to about 430 mm, which is slightly larger than the plate-making length A. Therefore, the control means 8
4 controls the solenoid 82 so that the cam plates 54a, 5
The control is performed so as to select 4a '. Master length D
For the above, the pressing length B is obtained by adding the leading end margin E and the trailing end margin F, and the leading end margin E needs to be about 80 mm and the trailing end margin F to be about 20 mm. Therefore, the master length D is about 530 mm. Become. This master length D is set by the outputs from the optical sensors 40 and 41 described with reference to FIG. 6, and the control means 84 shown in FIG. 5 controls the platen roller drive pulse motor 6 and the cutter drive motor 7. Is.

On the other hand, in FIG. 7B, the printing paper is "A4 landscape".
The relationship between the cutting length of the master and the pressing length of the impression cylinder executed when the master cylinder is stored in FIG. In this case, the plate making length A ′ of the master 2 is 200 mm. The pressing length B'is about 220 mm, which is slightly larger than the plate making length A '. Therefore, the control means 84 controls the solenoid 82 to control the cam plate 5
The control is performed so as to select 4b and 54b '. Regarding the master length D ′, the front end margin E is about 80 mm, which is the same as in the case of FIG. 7A, but the rear end margin F ′ is about 30 mm, which is slightly longer in this case. In the case of this example, the rear end margin F ′ is made slightly longer in the case where the rear end margin of the master 2 is located within the range of the opening of the printing drum 1, and the rear end of the master 2 is This is for avoiding the possibility that the rear end of the printing paper may directly touch the mesh screen 27 because it is located in the opening.
The rear end margin F ′ of the master 2 is made slightly longer in order to prevent the rear end of the printing paper from directly touching the mesh screen 27 and being contaminated with ink. This allows
Eventually, the master length D'is 330 mm. With respect to this master length D ', the control means 84 shown in FIG. 5 controls the platen roller drive pulse motor 6 and the cutter drive motor 7 by the outputs from the optical sensors 40 and 41 described in FIG.

As described above, even in the stencil printing apparatus which can store the "A3 portrait" in the paper feed table 31, the "A3 portrait" is uniformly used.
Rather than setting the master cutting length and impression cylinder pressing length to match the "vertical" size, the master cutting length and impression cylinder pressing length are switched for "A4 landscape" and smaller, so per plate Master length D (530 mm) -Master length D '(3
Since 30 mm) = 200 mm, masters of 200 mm or more can be saved.

Two. Relationship with Claim (1) Relationship between Embodiment and Claim 1 The pressing means is required to press the impression cylinder 20 against the printing drum 1 or separate them from each other in FIGS. 1, 2, and 4. It is a means for pressing the printing paper 3 only in such a case, and includes a swing arm 25, a pressing spring 26 which is a compression spring, cams 54 and 54 ′, a shaft 60 supporting these cams, and a pressure. It is composed of a body 20 and the like. The cam 54 is integral with cam plates 54a and 54b having cam surfaces,
The cam 54 'is a cam plate 54a', 54b 'having a cam surface.
Is integral with. In this example, the number of types of the pressing length of the printing paper is two, and the case of two cam surfaces is illustrated. However, the present invention is not limited to this, and when controlling for each printing paper size. Sets the number of types of cam surfaces in accordance with the number of types of printing paper that are expected to be used. The size detection means is shown in FIG.
The sensors 40 and 41 shown in FIGS. 5 and 6 are specific examples. Based on the information from these sensors 40 and 41, the platen roller drive pulse motor 6 and the cutter drive motor 7
Etc. are controlled to disconnect the master 2. The support member 81, the solenoid 82, the spring 83, the swing arm 63, the bearing cover 67, the bearing 68, the spring 69, etc. in FIG. 2 reciprocally move the shaft 60 provided with the cams 54, 54 ′ to switch the cam surface. Constitutes an example. in this way,
The information that is the basis for switching the cutting length of the heat-sensitive stencil sheet and the pressing length of the printing paper is the sensors 40, 4 that detect the size of the printing paper stored in the paper feeding unit 31, which is the printing paper storage unit.
Since it is required for the output of the size detecting means such as 1, and is not premised on the replacement of the print drum as in the prior art, the cost for preparing the print drum is high, and the print drum is replaced. It eliminates the complexity and time loss. Further, since the cam has as many types of cam surfaces as there are types of pressing length of the printing paper, it is possible to quickly deal with the switching of the pressing length by switching the cam surface.

(2) Relationship between the embodiment and claim 2 The cams 54, 54 'are provided integrally with the shaft 60 which is a rotary shaft, and the cam 54 has cam plates 54a, 54 having a cam surface.
Since b is arranged in the axial direction of the shaft 60, and cams 54a ′ and 54b ′ having cam surfaces are arranged in the longitudinal direction of the shaft 60 as well, different types of cams are provided. The surfaces are arranged in the axial direction of the shaft 60. With this configuration, the cam surface can be switched by simply moving the shaft 60 in the axial direction of the shaft, and the switching operation can be performed quickly.

(3) Relationship between the embodiment and claims 3 and 6 The shaft 60 provided with the cams 54 and 54 'is moved in the longitudinal direction of the shaft in accordance with turning on and off of the solenoid 82 constituting the switching means. Along with this movement, the cam plates 54a, 54a 'and the cam plates 54b, 54 relative to the cam followers 53, 53'.
The position of b'is determined. Therefore, the bearing cover 67, the solenoid 82, the swing arm 63, the support member 81, the stopper 7
1 and the like constitute switching position setting means for restricting movement of the shaft 60 in the axial direction. Also, these bearing covers 6
7, solenoid 82, swing arm 63, support member 81,
The configuration in which the spring 69 is added to the stopper 71 constitutes a holding unit that holds the shaft 60, whose movement in the axial direction is restricted by the switching position setting unit, at the restricted position.
In this way, the switching position of the cam surface is regulated by the switching position setting means, and is held at the switching position by the holding means, so that the switching operation becomes reliable. Further, in the example in which the number of types of the cam surface and the type of the pressing length of the printing paper is 2, it is possible to cope with the switching by two operations of pushing and returning the shaft 60, and the device configuration is simple. Is.

(4) Relationship between the embodiment and claims 4 and 7 The spring 69, which constitutes the switching means, biases the shaft 60 in the axial longitudinal direction, and constitutes the biasing means. Bearing cover 67, solenoid 82, swing arm 63, support member 81
The shaft 60 against the urging force of the spring 69 as the urging means.
Since it can be moved, it constitutes an example of the pushing means. In this way, since the biasing means is provided, the switching shaft can be pushed against the biasing direction of the biasing means to achieve the switching positioning, and the biasing means returns to the original position. It can be restored and the switching operation becomes easy. Further, as described above, in the example in which the number of types of the cam surface and the type of the pressing length of the printing paper is two, the switching operation of the cam surface can be performed by a simple means such as a solenoid.

(5) Relationship between the embodiment and claim 5 When the shaft 60 is moved by a drive device including a solenoid 82 as switching means, the solenoid 82 is controlled by the output of the control means 84. However, in addition to this, it can also be manually performed by a configuration in which the solenoid 82 is removed from the configuration shown in FIG. In the case of manual operation, the swing arm 63 is manually swung. In that case, in order to fix the position of the swing arm 63, an appropriate locking means for holding the position where the free end side of the swing arm 63 is pulled against the force of the spring 69 as shown in FIG. Will be collocated. In this way, the rotation shaft can be moved manually. It can also be automatically performed by the output of the control means.

[0059]

According to the first aspect of the present invention, the heat-sensitive stencil sheet is cut according to the size of the print sheet, so that the heat-sensitive stencil sheet can be economically used, and the printing paper and the heat-sensitive stencil sheet can be changed by switching the cam surface. Since the pressing length is quickly switched to, the first print time is shortened. In the invention according to claim 2, the cam surface can be switched only by moving the rotary shaft in the axial direction thereof.
The switching operation can be performed quickly. In the invention according to claim 3, since the switching position of the cam surface is regulated by the switching position setting means and is held by the holding means at the switching position, the switching operation becomes reliable. In the invention according to claim 4, the rotation shaft is pushed against the urging direction of the urging means, so that the switching can be positioned and the urging means can return to the original position. Switching operation becomes easy. In the invention according to claim 5, the rotation shaft can be moved manually. It can also be automatically performed by the output of the control means. Claim 6
In the described invention, when the number of types of the cam surface and the type of the pressing length of the printing paper is 2, it is possible to cope with the switching by two movements of the forward and backward movements of the shaft 60. Can be done easily. According to the invention described in claim 7, the switching operation of the cam surface can be quickly performed by a simple means such as a solenoid.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall outline of a stencil printing apparatus to which the present invention is applied.

FIG. 2 is a sectional view taken along the line [I]-[I] in FIG.

FIG. 3 is a perspective view of a bearing cover 67 portion.

FIG. 4 is a right side view of the impression cylinder and its peripheral members in FIG.

FIG. 5 is a control block diagram illustrating a control system for executing control according to the present invention.

FIG. 6 is a diagram illustrating the states of various printing sheets placed on a sheet feed table and the arrangement of sensors.

FIG. 7 is a development view of a printing drum.

[Explanation of symbols]

 20 Impression cylinder 25 Swing arm 26 Pressing spring 40 Optical sensor 41 Optical sensor 60 Shaft 63 Swing arm 67 Bearing cover 68 Bearing 69 Spring 54 Cam 54a Cam plate 54b Cam plate 54 'Cam 54a Cam plate 54b Cam plate 81 Support member 82 Solenoid 83 spring

Claims (7)

[Claims] 1. A plate-making section for making a plate on a roll-shaped heat-sensitive stencil sheet, a cutting section for cutting the heat-sensitive stencil sheet, a base paper feeding section for conveying the heat-sensitive stencil sheet, and the heat-sensitive stencil sheet on the outer periphery thereof. A print drum that wraps around a surface to supply ink, a print paper storage unit that can store print paper of different sizes, and the print paper stored in the print paper storage unit is supplied toward the print drum unit. A paper feeding unit for feeding, a pressing unit for pressing and releasing the roller-shaped rotating body against the outer peripheral surface of the printing drum by a printing unit via the printing paper sent by the paper feeding unit; Size detection means for detecting the size of the printing paper stored in the storage portion, control means for setting at least the cutting timing of the heat-sensitive stencil sheet in the cutting portion, and pressing means in the printing portion. According to the size of the printing paper, the thermal stencil sheet is cut according to the size of the printing paper, and the pressing length of the printing paper is set. In the above, the pressing unit has a cam that controls the pressing and the pressing release by the roller-shaped rotating body, and this cam has as many types of cam surfaces as there are types of the pressing length of the printing paper, A stencil printing apparatus, characterized in that the pressing length of the printing paper is switched by switching the cutting length of the heat-sensitive stencil sheet and the cam surface by the switching means based on the detection information of the size detecting means. 2. The stencil printing apparatus according to claim 1, wherein the cam is provided integrally with a rotary shaft that is rotationally driven in synchronization with the printing drum, and is arranged in a longitudinal direction of the rotary shaft. A stencil printing machine characterized in that the cam surfaces are arranged. 3. The stencil printing apparatus according to claim 1 or 2, wherein the switching means sets a switching position for restricting movement of the rotary shaft in a longitudinal direction of the shaft to a position where the cam surface is switched. A stencil printing machine comprising: means and a holding means for holding the rotating shaft at a position set by the switching position setting means. 4. The stencil printing apparatus according to claim 2, wherein the switching means biases the rotating shaft in a longitudinal direction of the rotation shaft, and the biasing means resists the biasing force of the biasing means. A stencil printing machine comprising: a pushing means for pushing a rotating shaft. 5. The stencil printing apparatus according to claim 4, wherein the rotation shaft is moved by the switching means manually or by a driving device. A stencil printing machine characterized by operating a pushing means. 6. Claim 1, claim 2, claim 3, claim 4
Alternatively, in the stencil printing apparatus according to claim 5, the number of types of the cam surface and the type of pressing length of the printing paper is set to two. 7. The stencil printing apparatus according to claim 4, wherein the pushing means includes a swing arm that pushes the rotary shaft in response to swing, and a solenoid that swings the swing arm. A stencil printing machine characterized by.