JPH1158914A - Stencil printing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform double-faced printing in one paper insertion, and single- faced printing without increasing cost by providing a pressing member with respect to the outer peripheral surface of each form cylinder capable of moving to and away therefrom between the counterposed form cylinders. SOLUTION: A printing part 6 and a printing part 9 are formed for their most part of a plate cylinder 49 and a plate cylinder 75 respectively. A press roller 48 is interposed between the printing part 6 and the printing part 9. During double-faced printing, printing images are transferred to the first face at a contact part between the form cylinder 49 and the press roller 48, and thereafter the swaying direction of the press roller 48 is changed for transferring printing images to the second face by transporting paper P in a contact part between the form cylinder 75 and the press roller 48. Following this, the form cylinders 49, 75 are positioned at the home position, and the press roller 48 is at the intermediate position respectively. During single-faced printing, printing images are transferred to the second face in a contact position between the press cylinder 75 and the press roller 48. Subsequently, the form cylinder 75 is positioned to the home position, and the press roller 48 is to the intermediate position respectively.

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 for performing double-sided printing or single-sided printing by winding a perforated master.

[0002]

2. Description of the Related Art A rotatable plate cylinder having a structure in which a plurality of mesh screens of a resin or metal mesh are wound around a porous support cylinder, and a thermoplastic resin film (thickness of 1 to 3 .mu.m).
And a thermoplastic resin film of the master using a laminated master in which a porous support made of Japanese paper fiber, synthetic fiber, or a mixture of Japanese paper fiber and synthetic fiber is attached to the same. After the plate is heated and perforated with a thermal head, the plate is wound around a plate cylinder, ink is supplied to the inner peripheral surface of the plate cylinder by ink supply means provided inside the plate cylinder, and printing paper is pressed by a pressing member such as an impression cylinder. Digital thermal stencil printing, in which ink is oozed from a plate cylinder opening portion and a master perforation portion is transferred to printing paper by pressing the printing plate onto a printing drum to perform printing, is well known.

In stencil printing, in recent years, there has been a tendency to increase double-sided printing in which printing is performed on both sides of printing paper for reasons such as saving printing paper or preventing files from increasing. When performing this two-sided printing using a normal printing device, the printing paper loaded in the paper feeding unit is fed to the printing unit, and after printing on one side, the printing paper is turned over and fed back to the printing unit again. However, printing on the other side can produce a two-sided printed material.However, it is troublesome to set the printed paper once discharged in the paper feeder or to align the printed paper after single-sided printing. There was a problem that it is.

[0004] In addition, the printed matter after printing is not sufficiently dried with ink, and if the printing is to be performed immediately on the back side, the conveying roller and the pressing member are pressed against the image area, and the printed image becomes dirty or disturbed. Therefore, in most cases, printing on the back side is performed after several hours or more, especially if there is a solid image part, drying for a long time is necessary, and printing on the back side is performed the next day. I was

As described above, in double-sided printing, the printing paper must be dried for a long time before printing on the back side of the printing paper, and the paper feeding operation is performed twice, which takes too much time. was there.

Therefore, a technique in which a pair of plate cylinders are arranged to face each other and the plate cylinders are pressed against each other to transfer a print image to both sides of printing paper in one process is disclosed in, for example, Japanese Patent Laid-Open Publication No.
No. 71996, JP-A-6-135111,
Japanese Patent Application Laid-Open No. 8-90893 discloses a technique in which two sets of a plate cylinder and a pressing member are provided and a print image is transferred to both sides of a printing sheet in one pass.

[0007]

However, Japanese Patent Laid-Open No. 6-7 / 1994
In the technology disclosed in JP-A-1996-135111 and JP-A-6-135111, the image transfer is performed by pressing the plate cylinders against each other, so that the image is almost the same as the image formed by pressing the normal plate cylinder and the pressing member. It is difficult to obtain the master, and it is necessary to wind an unmade master on one of the plate cylinders at the time of single-sided printing, resulting in an increase in cost due to waste of the master. In addition, even in the technique disclosed in Japanese Patent Application Laid-Open No. 8-90893, it is necessary to wind a blank master on one of the plate cylinders during single-side printing, resulting in an increase in cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a stencil printing apparatus which solves the above-mentioned problems and can perform double-sided printing with one pass of paper, and can perform single-sided printing without increasing costs.

[0009]

According to the first aspect of the present invention,
A first plate cylinder, a second plate cylinder opposed to the first plate cylinder, and a contact between the first plate cylinder and the second plate cylinder with respect to the outer peripheral surface of each plate cylinder; And a pressing member provided so as to be detachable.

According to a second aspect of the present invention, a first plate cylinder, a second plate cylinder opposed to the first plate cylinder, and a first plate cylinder and a second plate cylinder are provided between the first plate cylinder and the second plate cylinder. A pressing member provided so as to be able to freely contact and separate from the outer peripheral surface of each plate cylinder, a paper feeding unit for feeding printing paper, and a first surface of the printing paper fed from the paper feeding unit. A first paper transport path for transporting the printing paper between the outer peripheral surface of the first plate cylinder and the pressing member so as to face the outer peripheral surface of the first plate cylinder; A second plate for transporting the printing paper between the outer peripheral surface of the second plate cylinder and the pressing member such that the second surface of the paper faces the outer peripheral surface of the second plate cylinder; A sheet conveying path, and conveying path switching means for selectively switching the conveying path of the printing paper to one of a first sheet conveying path and a second sheet conveying path.

According to a third aspect of the present invention, there is provided a first plate cylinder, a second plate cylinder opposed to the first plate cylinder, and a space between the first plate cylinder and the second plate cylinder. A pressing member provided so as to be able to freely contact and separate from the outer peripheral surface of each plate cylinder, a paper feeding unit for feeding printing paper, and a first surface of the printing paper fed from the paper feeding unit. A first paper transport path for transporting the printing paper between the outer peripheral surface of the first plate cylinder and the pressing member so as to face the outer peripheral surface of the first plate cylinder; A second plate for transporting the printing paper between the outer peripheral surface of the second plate cylinder and the pressing member such that the second surface of the paper faces the outer peripheral surface of the second plate cylinder; A paper transport path, transport path switching means for selectively switching the transport path of the printing paper to one of a first paper transport path and a second paper transport path, and printing on both sides of the print paper. And a mode switching means for switching the printing mode to one of a single-sided printing mode for printing only on the second side of the printing paper, and the duplex printing mode is selected by the mode switching means. In this case, the transport path of the printing paper is switched to the first paper transport path by the transport path switching means, and a first plate cylinder is provided on the first surface of the print paper fed from the paper feeding means. The printing path is switched to the second paper transport path by the transport path switching means, and printing is performed on the second surface of the printing paper by a second plate cylinder, and the mode switching is performed. When the one-sided printing mode is selected by the means, the transport path of the printing paper is switched to the second paper transport path by the transport path switching means, and the second of the printing paper fed from the paper feeding means is switched. With a second plate cylinder And performing printing.

According to a fourth aspect of the present invention, there is provided a first plate cylinder, a second plate cylinder opposed to the first plate cylinder, and a space between the first plate cylinder and the second plate cylinder. A pressing member provided so as to be able to freely contact and separate from the outer peripheral surface of each plate cylinder, a paper feeding unit for feeding printing paper, and a first surface of the printing paper fed from the paper feeding unit. A first paper transport path for transporting the printing paper between the outer peripheral surface of the first plate cylinder and the pressing member so as to face the outer peripheral surface of the first plate cylinder; A second plate for transporting the printing paper between the outer peripheral surface of the second plate cylinder and the pressing member such that the second surface of the paper faces the outer peripheral surface of the second plate cylinder; A paper transport path, transport path switching means for selectively switching the transport path of the printing paper to one of a first paper transport path and a second paper transport path, and printing on both sides of the print paper. And a mode switching unit for switching a printing mode to one of a single-sided printing mode for printing only on the first side of the printing paper, and a duplex printing mode is selected by the mode switching unit. In this case, the transport path of the printing paper is switched to the first paper transport path by the transport path switching means, and a first plate cylinder is provided on the first surface of the print paper fed from the paper feeding means. The printing path is switched to the second paper transport path by the transport path switching means, and printing is performed on the second surface of the printing paper by a second plate cylinder, and the mode switching is performed. When the one-sided printing mode is selected by the means, the transport path of the printing paper is switched to the first paper transport path by the transport path switching means, and the first of the print paper fed from the paper feeding means is switched. With the first plate cylinder And performing printing.

According to a fifth aspect of the present invention, in the stencil printing apparatus according to the third or fourth aspect, further, in the double-sided printing mode, the reproduction of the image from the printing paper printed by the first plate cylinder is performed. It is characterized by having retransfer prevention means for preventing transfer.

According to a sixth aspect of the present invention, there is provided a first plate cylinder, a second plate cylinder opposed to the first plate cylinder, and a gap between the first plate cylinder and the second plate cylinder. A pressing member provided to be able to freely contact and separate from the outer peripheral surface of each plate cylinder, a first paper feeding means for feeding printing paper toward the first plate cylinder, and a pressing member for the second plate cylinder. A second sheet feeding means for feeding the printing paper, and a downstream side in the sheet conveying direction of the first plate cylinder, and provided between the second sheet feeding means and the second plate cylinder. Paper transport means capable of transporting the printing paper in a first direction and a second direction, a double-sided printing mode for printing on both sides of the printing paper, and single-sided printing for printing on only one side of the printing paper Mode switching means for switching the printing mode to any one of the modes, and when the duplex mode is selected by the mode switching means, the first paper feeding means After printing on one side of the fed printing paper with the first plate cylinder, the printing paper is sent to the paper feeding means for feeding the printing paper in a first direction, and the printing paper is fed to the paper feeding means. When the sheet reaches the upper predetermined position, the sheet conveying direction of the sheet conveying means is reversed in the second direction to convey the printing sheet to the second plate cylinder, and the second side of the printing sheet is When printing is performed by the plate cylinder and the single-sided printing mode is selected by the mode switching means, the printing paper fed from the second paper feeding means is fed to the paper transport means for transporting the printing paper in the second direction. The printing is performed by the second plate cylinder.

According to a seventh aspect of the present invention, there is provided the stencil printing apparatus according to any one of the first to sixth aspects, further comprising cleaning means for cleaning a surface of the pressing member. And

[0016]

FIG. 1 is a schematic side view of a stencil printing apparatus employing a first embodiment of the present invention. In FIG. 1, a stencil printing apparatus 1 includes an image reading unit 2, a sheet feeding unit 3 as a sheet feeding unit, a first plate making unit 4, a first plate discharging unit 5, a first printing unit 6, and a second printing unit 6.
Plate making section 7, second plate discharging section 8, second printing section 9, press roller 48 as a pressing member, sheet conveying section 10, sheet discharging section 1
1, mainly comprising a control unit 12 and the like.

An image reading section 2 is provided on an upper portion of a housing 13 of the stencil printing apparatus 1. The image reading unit 2 includes the original 1
Document tray 16 on which documents 14 and 15 are loaded, contact glass 17 on which documents 14 and 15 are placed, document transport roller pair 18 for transporting documents 14 and 15, and document transport roller 1
9. Guide plate 2 for guiding originals 14 and 15 to be conveyed
0, 21; a document transport belt 22 for transporting the documents 14, 15 along the contact glass 17;
A switching plate 23 for switching the discharge directions of the scanners 4, 15; reflection mirrors 24, 25 and a fluorescent lamp 26 for scanning and reading an original image; a lens 27 for focusing the scanned image; a CCD for processing the focused image; Mainly composed of an image sensor 28.

The paper feed unit 3 is disposed below the inside of the housing 13. The paper feed unit 3 stacks the printing paper P, and
The paper tray 29 provided for front loading by opening a door (not shown) of FIG.
It is mainly composed of a sheet feeding roller 30 for feeding sheets one by one.

A first plate-making section 4 is provided in the middle of the left side of the housing 13. The first plate making section 4 includes a master roll 32 formed by winding the master 31 in a roll shape, a thermal head 33 for heating and perforating the master 31, and a platen roller 3 for conveying the master 31 while pressing the master 31 against the thermal head 33.
4. It mainly comprises cutting means 35 for cutting the master 31, a pair of master transport rollers 36 and 37 for transporting the master 31, and the like.

The master roll 32 has its core 32a rotatably supported by supporting means (not shown). The platen roller 34 is driven to rotate by a stepping motor (not shown). The cutting means 35 includes a movable blade 35a.
Rotates or moves up and down with respect to the fixed blade 35b.

A first plate discharging section 5 is provided at the lower center of the housing 13. The first plate discharging section 5 mainly includes an upper plate discharging member 38, a lower plate discharging member 39, a plate discharging box 40, a compression plate 41, and the like.

The upper plate discharging member 38 is composed of a driving roller 42, a driven roller 43, and an endless belt 44. The endless belt 44 moves in the direction of the arrow in FIG. 1 when the driving roller 42 rotates clockwise in FIG. . Similarly to the upper plate discharging member 38, the lower plate discharging member 39 is also provided with the driving roller 4
5, the driven roller 46 and the endless belt 47. When the drive roller 45 rotates counterclockwise in FIG. 1, the endless belt 47 moves in the direction of the arrow in the figure. The lower plate discharging member 39 is movably provided by a moving means (not shown), and is selectively provided at a position shown in FIG. 1 and a position at which the outer peripheral surface of the drive roller 45 contacts an outer peripheral surface of a plate cylinder 49 described later. Positioned. The plate discharging box 40 for storing the printed master is provided detachably with respect to the housing 13. The compression plate 41 for pushing the printed master into the plate discharge box 40 is vertically movably supported by elevating means (not shown).

A first printing unit 6 is provided above the first plate discharging unit 5. The first printing section 6 mainly includes a plate cylinder 49 serving as a first plate cylinder. Inside the plate cylinder 49, an ink supply means 50 for supplying ink to the inner peripheral surface of the plate cylinder 49 is provided. Have been.

The plate cylinder 49 having a large number of apertures on the outer peripheral surface is
It is rotationally driven in the counterclockwise direction in the figure by plate cylinder driving means (not shown). On the outer peripheral surface of the plate cylinder 49, a stage section 51 and a clamper 52 for holding the master 31 made by the first plate making section 4 are arranged. The clamper 52 is pivotally mounted on the outer peripheral surface of the plate cylinder 49 by a shaft 52a, and is opened and closed by opening and closing means (not shown).

The ink supply means 50 mainly includes an ink supply pipe 53 also serving as a support shaft of the plate cylinder 49, an ink supply pipe 54 connected to the ink supply pipe 53, an ink roller 55, and a doctor roller 56. . The ink roller 55 is rotatably supported on a side plate (not shown) in the plate cylinder 49 by a support shaft 55a so that the outer peripheral surface of the ink roller 55 maintains a slight gap with the inner peripheral surface of the plate cylinder 49. The driving force from a rotationally driven plate cylinder driving unit (not shown) is transmitted by a driving force transmitting unit (not shown) such as a gear or a belt, so that the plate cylinder 49 is rotationally driven in the same direction as the plate cylinder 49. The doctor roller 56 has an outer peripheral surface and the ink roller 5.
5 so that a slight gap is formed between the plate cylinder 4 and the outer peripheral surface of the plate cylinder 5.
9 is rotatably supported by a not-shown side plate, and is driven to rotate in the opposite direction to the ink roller 55 by a driving force from a not-shown driving force transmitting means. When ink is supplied from an ink supply pipe 53 via an ink supply pipe 54 to a portion near the ink roller 55 and the doctor roller 56, a wedge-shaped ink pool 57 is formed. After a thin layer of ink is formed on the outer peripheral surface of the plate, the ink is supplied to the inner peripheral surface of the plate cylinder 49 by rotation of the plate cylinder 49 and the ink roller 55.

On the upper right side of the housing 13, a second plate making section 7 having the same structure as the first plate making section 4 is provided. The second plate making section 7 includes a master roll 59 formed by winding a master 58 in a roll shape, a thermal head 60, and a platen roller 6.
1. Cutting means 6 having movable blade 62a and fixed blade 62b
2. It is mainly composed of master transport roller pairs 63, 64 and the like.

On the upper left side of the housing 13, a second plate discharging section 8 configured similarly to the first plate discharging section 5 is provided. The second plate discharging section 8 includes an upper plate discharging member 65 having a driving roller 66, a driven roller 67, and an endless belt 68, and a driving roller 7.
0, a driven roller 71, and an endless belt 72, a lower plate discharging member 69, a plate discharging box 73, a compression plate 74, and the like. Thereby, the position shown in FIG. 1 and the position where the outer peripheral surface of the drive roller 70 contacts the outer peripheral surface of the plate cylinder 75 described later are selectively positioned.

A second printing unit 9 is provided between the second plate making unit 7 and the second plate discharging unit 8. The second printing unit 9 mainly includes a plate cylinder 75 as a second plate cylinder having a stage unit 76 and a clamper 77 on the outer peripheral surface.
5 has the same configuration as the ink supply means 50,
An ink supply means 78 having an ink supply pipe 79, an ink supply pipe 80, an ink roller 81, and a doctor roller 82 is provided. In the vicinity of the ink roller 81 and the doctor roller 82, a wedge-shaped ink reservoir 8 is provided.
3 is formed.

Between the first printing section 6 and the second printing section 9,
A press roller 48 is provided. The press roller 48 includes a pair of arm members 84 and 8 as shown in FIG.
A support shaft 48a is rotatably supported at one end of the support member 4, and a support shaft 85 rotatably supported by the housing 13 is fixed to the other end of each of the arm members 84, 84. A gear 86 is attached to one end of the support shaft 85, and a gear 88 attached to an output shaft of a forward / reversely rotating stepping motor 87 fixed to the housing 13 meshes with the gear 86. I have. On the outside of one arm member 84, four sensors 89a, 89b, 89 fixed to the housing 13 are provided.
c and 89 d are provided, and signals from each sensor are output to the control unit 12.

The operation of the stepping motor 87 is controlled by the control unit 12, and the press roller 48
As shown in FIG. 3A, the outer peripheral surface of each of the plate cylinders 49, 75
3 and a neutral position where it does not contact any of the outer peripheral surfaces.
A first pressing position where the outer peripheral surface presses the outer peripheral surface of the plate cylinder 49 as shown in FIG. 3B, and a second pressing position where the outer peripheral surface of the plate cylinder 75 is pressed with the outer peripheral surface as shown in FIG. It is selectively positioned at the pressing position. Positioning at each position is confirmed by signals from the sensors 89a, 89b, 89c, 89d. Further, when being positioned at the first pressing position and the second pressing position and being pressed against the outer peripheral surfaces of the plate cylinders 49 and 75, they are temporarily retracted to the neutral position with the rotation of the plate cylinders 49 and 75. Then, control is performed such that contact with each of the clampers 52 and 77 is prevented.

A sheet transport section 10 is provided so as to surround the first plate making section 4, the first plate discharging section 5, the first printing section 6, and the press roller 48. The paper transport unit 10 includes guide plates 90, 91, 92, 93, 94, 95, 96, 97,
98, 99, 100, 101, 102, 103, paper transport roller pairs 104, 105, 106, 107, 10
8, 109, 110, 111, 112, 113, pairs of registration rollers 114, 115, back conveying means 116, vertical conveying means 117, switching claw 11 as conveying path switching means.
8, a first peeling unit 119, a drying promoting unit 129 as a retransfer preventing unit, and the like.

The guide plate 90 and the guide plate 91 are vertically fixed to the right of the housing 13, and a guide plate 92 is fixedly provided so as to keep a predetermined distance from each of the guide plates 90 and 91. The downstream end of the guide plate 91 in the sheet transport direction is bent at substantially a right angle to form a bent portion 91a. Each guide plate 90, 9
The vertical transport path X is formed by 1,92
Paper transport roller pairs 104, 105, 10
6 are provided.

The guide plate 93 is arranged corresponding to the bent portion 91a, and each guide plate 94, 95 receives the printing paper P sent from the bent portion 91a and the guide plate 93, and horizontally moves so as to send it to the first printing portion 6. Are located. Bent section 91
a, a horizontal transport path Y as a first paper transport path is formed by each of the guide plates 93, 94, and 95, and a pair of paper transport rollers 107 is provided upstream of the horizontal transport path Y in the paper transport direction. A pair of registration rollers 114 are arranged on the downstream side.

In the vicinity of the plate cylinder 49, a first peeling means 119 for peeling the printing paper P from the outer peripheral surface of the plate cylinder 49 is provided. The first peeling unit 119 mainly includes a peeling claw 130 and a blower fan 131. Peeling nail 1
The tip of the plate 30 is provided so as to be freely movable toward and away from the outer peripheral surface of the plate cylinder 49, and is rocked by rocking means (not shown). The blower fan 131 is provided with the plate cylinder 4
In order to assist the peeling of the printing paper P from the outer peripheral surface of 9, air is blown toward a position close to the separating claw 130 and the plate cylinder 49.

On the downstream side of the first printing unit 6 in the paper transport direction, a rear transport unit 116 is provided. Back transfer means 11
Reference numeral 6 mainly includes a driving roller 120, a driven roller 121, an endless belt 122, and a suction fan 123. The suction force of the suction fan 123 is applied to the endless belt 122 which moves in the direction of the arrow in FIG. The printing paper P is conveyed while being sucked.

A guide plate 96 which is bent at a substantially right angle is disposed on the downstream side of the back conveying means 116 in the sheet conveying direction. The guide plate 96 sends the printing paper P sent from the back conveyance means 116 to the vertical conveyance means 117.

The vertical transport means 117 includes the drive roller 12
4, mainly composed of a driven roller 125, an endless belt 126, a suction fan 127, and a blower fan 128. The endless belt 126, which moves in the direction of the arrow in FIG. The printing paper P is blown by blowing air from the blowing fan 128.
And transporting it.

On the downstream side of the vertical transport means 117 in the paper transport direction, there is disposed a guide plate 97 which is bent at a substantially right angle. The guide plate 97 sends the printing paper P sent from the vertical conveyance means 117 to the horizontal conveyance path Y1.

On the downstream side of the guide plate 97 in the sheet transport direction,
Guide plates 98 and 99 are horizontally arranged at a predetermined interval. The horizontal transport path Y is formed by the guide plates 98 and 99.
In the horizontal transport path Y1, drying promoting means 129, each pair of paper transport rollers 108, 109, 110, and 111, and the paper detection sensor 1 are provided from the upstream side in the paper transport direction.
32 are provided. The printing paper P sent from the paper transport roller pair 111 is delivered to the paper transport roller pair 104 and sent to the vertical transport path X.

The drying promoting means 129 includes a heating roller 129a which has a heater inside and is driven to rotate by a driving means (not shown), and a pressing roller 129b which is disposed in pressure contact with the heating roller 129a and rotates together with the heating roller 129a. It is composed of When the printed printing paper P passes through the drying promoting means 129,
The printing surface is heated by the heating roller 129a, and excess ink is removed. In addition, as drying promotion means,
In addition to the heating roller 129a and the pressing roller 129b, a method of sucking ink on the paper surface with a blotting paper or the like, a method of removing the ink on the paper surface by pressing the roller and cleaning it with a liquid compatible with the ink. And a method of spraying a coating such as varnish on the printed image surface, and the like.

The paper detection sensor 132, which is a well-known proximity sensor, detects whether the printing paper P has passed through the horizontal transport path Y1, and when the printing paper P has passed, the control unit 1
Send a signal to 2.

Above the guide plates 91 and 92, there are disposed guide plates 100 and 101 corresponding to the respective guide plates 91 and 92 for receiving the printing paper P. Each guide plate 1
00 and 101 are each formed at a substantially right angle.
A paper transport roller pair 112 is provided in the path.

On the downstream side of the guide plates 100 and 101 in the sheet transport direction, guide plates 102 and 103 for relaying the printing paper P transported by the guide plates 100 and 101 and sending them to the second printing unit 9. Are arranged. A pair of sheet transport rollers 113 is disposed upstream of each of the guide plates 102 and 103 in the sheet transport direction, and a pair of registration rollers 115 is disposed downstream of the guide plates 102 and 103 in the sheet transport direction.

Each of the guide plates 100, 101, 10 described above
2, 103 form a right-angle transport path Z as a second paper transport path.

The guide plate 92 and the guide plate 1 which are branch points between the vertical transport path X and the horizontal transport path Y or the right-angle transport path Z.
A swingable switching claw 118 is provided between the switching claw 118 and the switching lever 118. The switching claw 118 is rocked by a rocking means (not shown) such as a solenoid or a motor, and is selectively positioned at a solid line position and a two-dot chain line position in the figure.

In the middle of the left side of the housing 13, below the second plate discharging unit 8 and to the left of the second printing unit 9,
Are arranged. The paper discharge unit 11 includes a second peeling unit 13
3, mainly composed of a paper discharge conveying means 134 and a paper discharge tray 135.

As in the case of the first peeling means 119, the second peeling means 133 disposed near the plate cylinder 75 has its tip provided so as to be close to and away from the outer peripheral surface of the plate cylinder 75. It mainly includes a peeling claw 136 that is rocked by a rocking means that does not rotate, and a blower fan 137 that blows air toward a position near the peeling claw 136 and the plate cylinder 75.

The paper discharging and conveying means 134 is
8, the printing paper P mainly composed of the driven roller 139, the endless belt 140, and the suction fan 141, and the printing paper P peeled off from the outer peripheral surface of the plate cylinder 75 by the second peeling means 133 by the suction force of the suction fan 141. While being sucked onto 140, the sheet is conveyed in the direction of the arrow by the driving force of the driving roller 138.

The paper discharge tray 135 on which the printing paper P conveyed by the paper discharge conveying means 134 is stacked is a pair of paper trays movable in the width direction of the printing paper P (a direction orthogonal to the conveying direction of the printing paper P). And an end fence 143, and can be stored inside the housing 13 by folding.

The control unit 1 disposed at the lower right side of the housing 13
Reference numeral 2 denotes a well-known microcomputer, which controls the operation of the stencil printing apparatus 1.

An operation panel 144 is provided on the upper front surface of the housing 13.
Are arranged. As shown in FIG. 4, the operation panel 144 includes a plate making start key 145 and a printing start key 14.
6. Trial printing key 147, stop key 148, numeric keypad 149, clear key 150, enlargement / reduction key 151, printing speed setting key 152, continuous shooting key 153, display device 154 including 7-segment LED, display device 155 including LCD, etc. , A mode switching key 156 as mode switching means for switching a printing mode between a duplex printing mode and a single-sided printing mode, and two LEDs for displaying the printing mode as "double-sided" and "single-sided". Mode display means 157 is provided.

The operation of double-sided printing using the stencil printing apparatus 1 based on the above configuration will be described. Two manuscripts 14, 15
When the mode switch key 156 is pressed by the operator to select the double-sided printing mode, the LED of the printing mode display means 157 is turned on “double-sided” and a signal is sent from the control unit 12. Then, the switching claw 118 is positioned at the position indicated by the solid line in FIG.

Thereafter, when the plate making start key 145 is pressed, the plate cylinder 49 rotates clockwise in FIG.
The printed master wound on the outer peripheral surface of the plate cylinder 49 is peeled off by the upper plate discharging member 38 and the lower plate discharging member 39,
After the printed master is stored in the plate discharge box 40, it is compressed by the compression plate 41.

Similarly, the plate cylinder 75 also rotates counterclockwise in FIG. 1, and the printed master wound on the outer peripheral surface of the plate cylinder 75 is separated by the upper plate discharging member 65 and the lower plate discharging member 69. The sheet is conveyed into the plate discharge box 73 and is compressed by the compression plate 74.

At the time of the above-mentioned plate discharging, the press roller 4
8 is positioned at the neutral position, and each plate cylinder 49, 75
Contact with has been avoided. Thereafter, each plate cylinder 49, 75
Is rotated to a predetermined plate feeding standby position and stopped, and a moving means (not shown) is operated to position the lower plate discharging members 39 and 69 at the positions shown in FIG. 1 to complete the plate discharging operation.

Next, the original conveying roller pair 18 of the image reading section 2 rotates, and the upper one of the two originals 14 and 15 is moved.
The original 14 which is a sheet is conveyed on the contact glass 17 and read. The image of the document 14 read at this time is printed on the back side of the printing paper P.

In the reading operation, the reflected light from the surface of the document 14 exposed by the fluorescent lamp 26 is reflected by the reflection mirrors 24 and 25.
The read original image is condensed by a lens 27, is incident on an image sensor 28, and is photoelectrically converted, and the photoelectrically converted electric signal is transmitted to an A / D (not shown) in the housing 13. Input to the converter. The document 14 from which the image has been read is discharged by a document transport belt 22 and a document transport roller 19 to a document tray (not shown) disposed above the document transport belt 22.

In parallel with the original reading operation, the first plate making section 4 performs a plate making operation. After the plate discharging operation is completed, the platen roller 34 and the master transport roller pairs 36 and 37 start rotating, respectively, and the master 31 is pulled out from the master roll 32. The drawn-out master 31 is subjected to plate making when passing through the thermal head 33. The plurality of heating elements arranged and arranged on the surface of the thermal head 33 are selectively provided in accordance with digital image signals sent after being subjected to various processes by an A / D converter and other plate making boards (not shown). Heat is generated, and the thermoplastic resin film of the master 31 is melt-punched.

According to the number of steps of a stepping motor (not shown) that rotationally drives the platen roller 34, the leading end of the master 31 is moved to the stage 51 and the clamper 5
When it is determined that the master 31 has reached the predetermined position between the two, the opening / closing means (not shown) is operated to rotate the clamper 52, and the stage section 51 and the clamper 52 hold the leading end of the master 31.

Thereafter, the plate cylinder 49 rotates counterclockwise in FIG. 1 at the same peripheral speed as the transport speed of the master 31,
The operation of winding the master 31 around the plate cylinder 49 is performed. When it is determined from the number of steps of a stepping motor (not shown) that plate making for one plate is completed, the rotation of the platen roller 34 and the master transport roller pair 36, 37 is stopped, and the movable blade 35a is rotated. The master 31 is disconnected. The cut master 31 is pulled out by the rotation of the plate cylinder 49, and the plate cylinder 49 is again positioned at the home position.

After the positioning of the plate cylinder 49, the original conveying roller pair 18 rotates again, and the remaining original 15 is conveyed on the contact glass 17 and read in the same manner as described above.
The image of the document 15 read at this time is printed on the front side of the printing paper P. The document 15 from which the image has been read is discharged to a document tray (not shown).

In this embodiment, the image is read from the two originals 14 and 15, respectively. However, when reading the image from both sides of one original, the original conveying belt 22 is read after the reading of one side is completed. At the same time as the document transport roller 19 is rotated, the switching plate 23 is rotated counterclockwise in FIG. 1 by a mechanism (not shown), so that the traveling direction of the document is changed and guided again onto the contact glass 17. Is configured to be read.

In parallel with the original reading operation, the second plate making section 7 performs a plate making operation in the same manner as the first plate making section 4. After the plate discharging operation is completed, the platen roller 61 and the master transport roller pairs 63 and 64 start rotating, and the master roll 59 is rotated.
Is pulled out of the master 58. Master 5 withdrawn
8 is a thermal head 6 similar to the master 31 described above.
The plate is made when passing through zero.

When it is determined from the number of steps of a stepping motor (not shown) that rotates the platen roller 61 that the leading end of the master 58 has reached a predetermined position, the opening / closing means (not shown) operates to operate the clamper 77.
Rotates, and the leading end of the master 58 is held between the stage section 76 and the clamper 77.

Thereafter, the plate cylinder 75 rotates clockwise in FIG. 1 at the same peripheral speed as the transfer speed of the master 58, and the operation of winding the master 58 around the plate cylinder 75 is performed. And
From the number of steps of a stepping motor not shown, 1
When it is determined that the plate making for the plate has been completed, the rotation of the platen roller 61 and the master transport roller pairs 63 and 64 is stopped, and the movable blade 62a is rotated and the master 58 is cut. The cut master 58 is pulled out by the rotation of the plate cylinder 75, and the plate cylinder 75 is again positioned at the home position.

At the time of the above-described plate feeding, the press roller 48 is positioned at the neutral position, as at the time of plate discharging.
Contact with the plate cylinders 49 and 75 is avoided.

At the same time when the plate feeding operation to each of the plate cylinders 49 and 75 is completed, the paper feed roller 30 is rotated, and the uppermost one of the printing papers P stacked on the paper feed tray 29 is moved to the vertical transport path X.
And the plate cylinders 49 and 75 rotate synchronously at a low speed.

The paper is separated and fed from the paper feeding unit 3 and is
Is sent to the horizontal transport path Y while being guided by the switching claw 118, and the leading end thereof is gripped by the registration roller pair 114. Thereafter, the printing paper P is fed between the outer peripheral surface of the plate cylinder 49 and the press roller 48 swinging to the first pressing position by rotating the registration roller pair 114 at a predetermined timing. .

The printing paper P fed by the registration roller pair 114 has its print image transferred to its first surface (the back surface in a double-sided printed matter) at the contact portion between the plate cylinder 49 and the press roller 48, and While being peeled off from the outer peripheral surface of the plate cylinder 49 by the peeling means 119,
Sent to 6. Suction fan 123 of back conveyance means 116
The printing paper P whose non-printing surface has been sucked onto the endless belt 122 by this is sent to the guide plate 96.

The printing paper P whose traveling direction has been changed downward when passing through the guide plate 96 is directed downward while the non-printing surface is sucked onto the endless belt 126 by the suction fan 127 of the vertical transport means 117. Conveyed, guide plate 9
7

The printing paper P sent to the guide plate 97 is transported to the horizontal transport path Y1 with the traveling direction changed to the right. The printing paper P conveyed to the horizontal conveyance path Y1 is conveyed rightward while drying the printing surface by the drying promotion means 129. When the printing paper P passes through the paper detection sensor 132 during this conveyance, this signal is sent to the control unit 12.
The control unit 12 that has received this signal
8 is switched to the position indicated by the two-dot chain line in FIG. At the same time, the rotation direction of the stepping motor 87 is switched, and the swing direction of the press roller 48 is switched.

The printing paper P transported from the horizontal transport path Y1
Is sent to the vertical transport path X again by the rotational force of the sheet transport roller pair 111. Then, the paper transport roller pair 1
06, the printing paper P sent out from the vertical transport path X
Is guided by the switching claw 118 to the right-angled conveyance path Z, and the leading end thereof is added to the registration roller pair 115. When the registration roller pair 115 rotates at a predetermined timing, the printing paper P is pressed by the press roller 48 swinging to the outer peripheral surface of the plate cylinder 75 and the second pressing position.
It is fed to between.

The printing paper P fed by the pair of registration rollers 115 is transferred to the second surface (the surface in a double-sided printed material) of the printing paper P at the contact portion between the plate cylinder 75 and the press roller 48, and the peeling nail is formed. The sheet 136 is sent to the sheet discharging and conveying means 134 while being separated from the outer peripheral surface of the plate cylinder 75 by 136.

The printing paper P sent to the paper discharging / conveying means 134
Is conveyed while being suctioned onto the endless belt 140 by the suction fan 141, and is discharged onto the paper discharge tray 135. At this time, the printing paper P is discharged such that the image on the second surface side (the image of the second document 15) faces upward.

Thereafter, the plate cylinders 49 and 75 rotate to the home position and stop, and the press roller 48 is positioned at the neutral position to complete the plate attaching operation.

Thereafter, when the operator presses the test print key 147, the uppermost sheet of printing paper P on the paper feed tray 29 is pulled out by the paper feed roller 30 in the same manner as in the plate attaching operation, and the vertical transport path is set. The tip of the registration roller pair 114 is held through the X and horizontal transport paths Y. The plate cylinders 49 and 75 are also rotationally driven at high speed in synchronization.

When the printing paper P is fed between the printing drum 49 and the press roller 48 where the registration roller pair 114 rotates at a high speed at the same timing as the printing operation, the printing paper P
Is transferred to the first surface, and is conveyed while being separated from the outer peripheral surface of the plate cylinder 49 by the separation claw 130.

Thereafter, the printing paper P having its leading edge added to the pair of registration rollers 115 through the right-angled conveying path Z along the same path as the printing plate operation is rotated by the rotation of the registration roller pair 115 to perform the printing operation. At the same timing as above, it is fed between the plate cylinder 75 rotating at a high speed and the press roller 48, and the print image is transferred to the second surface.

Printing paper P on which print images are transferred on both sides
Is transported by the paper discharging and transporting means 134 while being peeled from the outer peripheral surface of the plate cylinder 75 by the peeling claw 136, and is discharged onto the paper discharging tray 135 to complete the test printing.

The density and position of the printed image are confirmed by the above-described test printing, and these are adjusted with various keys on the operation panel 144, and the test printing is performed again. Then, the number of prints is displayed on the display device 154 using the ten keys 149. By pressing the print start key 146 a number of times, the printing paper P is continuously sent from the paper feeding unit 3 and the printing operation is performed.

Next, the operation during single-sided printing using the stencil printing apparatus 1 will be described. When one document (for example, the document 14) is set on the document receiving tray 16, and the mode switching key 156 is pressed by the operator to select the one-sided printing mode, the LED of the printing mode display means 157 is turned on in "one-sided". At the same time, a signal is sent from the control unit 12 and the switching claw 1
18 is positioned at the position indicated by the two-dot chain line in FIG.

Thereafter, when the plate making start key 145 is pressed, the plate cylinder 75 rotates counterclockwise in FIG. 1, and the printed master wound on the outer peripheral surface of the plate cylinder 75 is moved to the upper plate discharging member 65. , And are conveyed into the plate discharge box 73 and compressed by the compression plate 74.

At the time of the above-mentioned plate discharging, the press roller 4
8 is positioned at the neutral position, and each plate cylinder 49, 75
Contact with has been avoided. The printed master wound on the outer peripheral surface of the plate cylinder 49 is wound as it is without discharging the plate.

Next, the original conveying roller pair 18 of the image reading section 2 rotates, the original 14 is conveyed on the contact glass 17, and the reading operation is performed in the same manner as in double-sided printing. In parallel with the document reading operation, a plate making operation for the master 58 is performed in the second plate making section 7 in the same manner as described above. Prepressed master 58
Is clamped between the stage section 76 and the clamper 77 and wound around the outer peripheral surface of the plate cylinder 75. Master 58
Is again positioned at the home position.

At the same time when the plate cylinder 75 is positioned, the paper feed roller 30 is rotated, the printing paper P on the paper feed tray 29 is separated and fed toward the vertical transport path X, and the plate cylinder 75 is moved at a low speed. Rotate.

The sheet is separated and fed from the sheet feeding unit 3 and is
Is sent to the right-angled conveyance path Z by being guided by the switching claw 118, and the leading end thereof is added to the registration roller pair 115. Thereafter, the printing paper P is fed between the outer peripheral surface of the plate cylinder 75 and the press roller 48 swinging to the second pressing position by rotating the registration roller pair 115 at a predetermined timing. .

The printing paper P fed by the pair of registration rollers 115 has a printing image transferred to the second surface of the printing paper P at a contact portion between the printing cylinder 75 and the press roller 48. While being peeled off from the outer peripheral surface, the sheet is sent to the sheet discharge conveyance means 134 and discharged to the sheet discharge tray 135. Thereafter, the plate cylinder 75 is positioned at the home position and the press roller 48 is positioned at the neutral position, and the plate attaching operation is completed.

After the printing operation is completed, test printing is performed, and after adjusting the density and position of the print image with various keys on the operation panel 144, the print start key 146 is pressed. P is continuously sent to perform a printing operation.

As described above, during the duplex printing, the back conveyance means 116 and the vertical conveyance means 117 convey the printing paper P while sucking the non-printing surface. Thus, a good double-sided printed material can be obtained by preventing the above.
By using only 5, a single-sided printed material can be obtained without wasteful use of a blank master. Further, since both the double-sided printing and the single-sided printing can be covered by one sheet feeding tray 29 and one sheet discharging tray 135, cost reduction and installation space reduction can be achieved at the same time.

FIG. 7 is a schematic side view of a stencil printing apparatus 212 adopting a modification of the first embodiment of the present invention. This stencil printing apparatus 212 is different from the stencil printing apparatus 1 in that
A control unit 213 composed of a microcomputer storing a program different from the control unit 12 is used; a guide plate 214 is used instead of the guide plate 96;
Is different only in that the other components are used, and the other configurations are the same. The same portions as those already described in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The guide plate 214 is disposed on the downstream side in the sheet conveying direction of the rear conveying means 116, and the casing 13 is arranged substantially linearly with the guide plate 94 and the rear conveying means 116.
It is stuck to.

A swingable switching claw 215 is disposed on the downstream side of the guide plate 214 in the sheet transport direction. The switching claw 215 is oscillated by oscillating means (not shown) such as a solenoid or a motor, and is selectively positioned at a solid line position and a two-dot chain line position in the figure.

The operation during double-sided printing using the stencil printing apparatus 212 will be described below. When the two originals 14 and 15 are set on the original receiving table 16 and the mode switch key 156 is pressed by the operator to select the double-sided printing mode, the LED of the printing mode display means 157 is turned on in "double-sided". 7, a signal is sent from the control unit 213, and the switching claws 118 and 215 are positioned at the solid line positions in FIG.

Thereafter, when the plate making start key 145 is pressed, the printed master is peeled off from the outer peripheral surfaces of the plate cylinders 49 and 75, as in the first embodiment.
Discarded in 0,73. After the plate discharging operation is completed, a reading operation is performed, and then a plate making operation is performed. Each plate cylinder 49, 75
Is wound at the home position after the stencil masters 31 and 58 are wound on its outer peripheral surface, and the stencil feeding operation is completed.

At the same time when the plate feeding operation to each of the plate cylinders 49 and 75 is completed, the paper feed roller 30 is rotated, and the uppermost one of the printing papers P stacked on the paper feed tray 29 is moved to the vertical transport path X.
And the plate cylinders 49 and 75 rotate synchronously at a low speed.

Separated and fed from the paper feed unit 3, the vertical conveying path X
Is sent to the horizontal transport path Y while being guided by the switching claw 118, and the leading end thereof is gripped by the registration roller pair 114. Thereafter, the printing paper P is fed between the outer peripheral surface of the plate cylinder 49 and the press roller 48 swinging to the first pressing position by rotating the registration roller pair 114 at a predetermined timing. .

The printing paper P fed by the registration roller pair 114 is transferred with a print image on its first surface (the back surface in a double-sided printed material) at the contact portion between the plate cylinder 49 and the press roller 48, and While being peeled off from the outer peripheral surface of the plate cylinder 49 by the peeling means 119,
Sent to 6. Suction fan 123 of back conveyance means 116
The printing paper P whose non-printing surface has been suctioned onto the endless belt 122 by the guide plate 214 is guided by the switching plate 215.
Sent to.

The printing paper P whose traveling direction has been changed downward by the switching claw 215 is conveyed downward while the non-printing surface is sucked onto the endless belt 126 by the suction fan 127 of the vertical conveying means 117, and is guided. It is sent to the plate 97.

The printing paper P sent to the guide plate 97 is transported to the horizontal transport path Y1 with its traveling direction changed to the right. The printing paper P conveyed to the horizontal conveyance path Y1 is conveyed rightward while drying the printing surface by the drying promotion means 129. When the printing paper P passes through the paper detection sensor 132 during this conveyance, this signal is sent to the control unit 21.
The controller 213 receives this signal and switches the switching claw 118 to the position indicated by the two-dot chain line in FIG. At the same time, the rotation direction of the stepping motor 87 is switched, and the swing direction of the press roller 48 is switched.

Printing paper P transported from horizontal transport path Y1
Is sent to the vertical transport path X again by the rotational force of the sheet transport roller pair 111. Then, the paper transport roller pair 1
06, the printing paper P sent out from the vertical transport path X
Is guided by the switching claw 118 to the right-angled conveyance path Z, and the leading end thereof is added to the registration roller pair 115. When the registration roller pair 115 rotates at a predetermined timing, the printing paper P is pressed by the press roller 48 swinging to the outer peripheral surface of the plate cylinder 75 and the second pressing position.
It is fed to between.

The printing paper P fed by the registration roller pair 115 is transferred to the second surface (the surface in a double-sided printed material) of the printing paper P at the contact portion between the plate cylinder 75 and the press roller 48, and the peeling nail is formed. The sheet 136 is sent to the sheet discharging and conveying means 134 while being separated from the outer peripheral surface of the plate cylinder 75 by 136.

The printing paper P sent to the paper discharging / conveying means 134
Is conveyed while being suctioned onto the endless belt 140 by the suction fan 141, and is discharged onto the paper discharge tray 135. At this time, the printing paper P is discharged such that the image on the second surface side (the image of the second document 15) faces upward.

Thereafter, the plate cylinders 49 and 75 rotate to the home position and stop, and the press roller 48 is positioned at the neutral position to complete the plate attaching operation.

Thereafter, when the test print key 147 is pressed by the operator, the print paper is fed in the same manner as described above, and the test print is performed in the same manner as in the first embodiment. Is adjusted, the number of prints is set on the display device 154 using the numeric keypad 149, and the print start key 146 is pressed, whereby the print paper P is continuously sent from the paper supply unit 3 to perform a print operation.

Next, the operation at the time of single-sided printing using the stencil printing apparatus 212 will be described. One manuscript (eg manuscript 14)
Is set on the document receiving table 16, and when the mode switching key 156 is pressed by the operator to select the one-sided printing mode, the LED of the printing mode display means 157 is turned on "one-sided" and a signal is sent from the control unit 213. Then, the switching claw 118 is positioned at the solid line position in FIG. 7, and the switching claw 215 is positioned at the two-dot chain line position in FIG.

Thereafter, when the plate making start key 145 is pressed, the plate discharging operation, the reading operation, the plate making operation, and the plate feeding operation for the plate cylinder 49 are sequentially performed, and the plate cylinder 49 is positioned at the home position. At this time, the printed master wound around the outer peripheral surface of the plate cylinder 75 is wound as it is without discharging the plate, and the plate cylinder 75 is positioned at the home position.

At the same time as the plate cylinder 49 is positioned, the paper feed roller 30 rotates, and the printing paper P on the paper feed tray 29 is separated and fed toward the vertical transport path X, and the plate cylinder 49 is moved at a low speed. Rotate.

The sheet is separated and fed from the sheet feeding unit 3 and is
Is sent to the horizontal transport path Y while being guided by the switching claw 118, and the leading end thereof is gripped by the registration roller pair 114. Thereafter, the printing paper P is fed between the outer peripheral surface of the plate cylinder 49 and the press roller 48 swinging to the first pressing position by rotating the registration roller pair 114 at a predetermined timing. .

The printing paper P fed by the registration roller pair 114 is transferred with a print image on the first surface thereof at the contact portion between the plate cylinder 49 and the press roller 48, and is released by the peeling claw 130. While being separated from the outer peripheral surface, the sheet is sent to the rear conveying means 116, guided by the guide plate 214 and the switching claw 215, and discharged to the sheet discharge tray 135. Thereafter, the plate cylinder 49 is positioned at the home position and the press roller 48 is positioned at the neutral position, and the printing operation is completed.

After the printing operation is completed, test printing is performed, and after adjusting the density and position of the print image with various keys on the operation panel 144, the print start key 146 is pressed. P is continuously sent to perform a printing operation.

FIG. 5 is a schematic side view of a stencil printing apparatus 158 employing the second embodiment of the present invention. The stencil printing apparatus 158 is different from the stencil printing apparatus 1 in that a sheet transport unit 159 is used instead of the sheet transport unit 10,
1 in that a paper discharge unit 160 is used, a control unit 161 including a microcomputer storing a program different from the control unit 12 is used, and a second paper supply unit 162 as a second paper supply unit is provided. And a sheet transport means 163, and the other configuration is the same. The same portions as those already described in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The paper transport section 159 includes guide plates 164, 1
65,166,167, paper transport roller pair 168,1
69, 170, 171, a pair of registration rollers 172, a paper conveyor 173, and the like.

The guide plate 164 and the guide plate 165 are fixed vertically to the right of the housing 13 at a predetermined interval. The downstream ends of the guide plates 164 and 165 in the sheet transport direction are bent at substantially right angles to form bent portions 164a and 165a. A vertical transport path X1 is formed by each of the guide plates 164 and 165, and each pair of paper transport rollers 168, 169, and 170 is disposed in the vertical transport path X1.

The print paper P sent from the vertical transport path X1 and having its transport direction changed to the left at the bent section is directed to the first printing section 6 downstream of the bent sections 164a and 165a in the sheet transport direction. And guide plates 166 and 167 for carrying the sheet. A horizontal transport path Y2 is formed by the guide plates 166 and 167, and a pair of paper transport rollers 171 and a pair of registration rollers 172 are disposed in the horizontal transport path Y2.

A paper conveyor 173 is provided downstream of the first printing unit 6 in the paper transport direction. Paper conveyor 17
Reference numeral 3 denotes a drive roller 174, driven rollers 175 and 176, an endless belt 177 stretched between the rollers, a drive roller 174 and a driven roller 1 arranged in a triangle.
75, and the driving roller 174 and the driven roller 1
76 and two suction fans 17 respectively disposed between
8, 179 and a guide claw 180.

Each of the driven rollers 175 and 176 is disposed near the left of the contact portion between the press roller 48 and each of the plate cylinders 49 and 75, and has an axis passing through the center of each of the driven rollers 175 and 176 as a base. A drive roller 174 is provided at a position forming an isosceles triangle. Guide claw 180
Means that the printing paper P from the first printing unit 6 is
3 so that the printing paper P from the paper transporting means 163 is transported toward the second printing unit 9 so as to have a substantially triangular shape.

The paper discharge unit 1 disposed in the middle right section of the housing 13
Reference numeral 60 mainly includes a guide plate 181, a second peeling unit 182, a sheet discharging and conveying unit 183, a sheet discharging tray 184, and the like. The guide plate 181 is disposed downstream of the second printing unit 9 in the sheet transport direction, and includes a plate cylinder 75 and a press roller 48.
Guides the printing paper P sent out from the contact portion with the printing paper P.
The second peeling unit 182 is similar to the second peeling unit 133,
The printing paper P is peeled off from the outer peripheral surface of the plate cylinder 75 and includes a peeling claw 185 and a blower fan 186. The paper discharging and conveying means 183 includes a driving roller 187, a driven roller 188,
It mainly includes an endless belt 189 and a suction fan 190, and transports the printing paper P while holding it on the surface of the endless belt 189. The paper discharge tray 184 has a pair of side fences 191 and 191 and an end fence 192, and the print paper P conveyed by the paper discharge conveyance unit 183.
Loading.

In the middle section on the left side of the housing 13, the second paper feeding section 16
2 are provided. The second paper feed unit 162 mainly includes a paper feed tray 193, a paper feed roller 194, guide plates 195 and 196, and a pair of paper transport rollers 197 and 198. The printing paper P1 stacked on a vertically movable paper feed tray 193 is separated and fed by a paper feed roller 194, passes between guide plates 195 and 196 fixed to the housing 13, and passes through a pair of paper transport rollers 197 and 197. It is conveyed by the rotation force of 198. Further, a well-known paper size detection sensor (not shown) is provided in the paper feed tray 193, and a signal from this sensor is sent to the control unit 161.

A sheet conveying means 163 is provided downstream of the second sheet feeding section 162 in the sheet conveying direction. The paper transport unit 163 includes a drive roller 199 that can be rotated forward and backward, a driven roller 200, an endless belt 201, a suction fan 202,
Blower fan 203, first sheet detection sensor 216, second
The printing apparatus mainly includes a sheet detection sensor 204, and conveys the printing sheet P1 while holding it on the endless belt 201 by the suction force of the suction fan 202 and the blowing force from the blower fan 203. Signals from the first sheet detection sensor 216 and the second sheet detection sensor 204 are output to the control unit 161, and the drive roller 199 rotates forward and reverse according to the signal from the control unit 161.

Based on the above configuration, the stencil printing device 15
The operation at the time of double-sided printing using No. 8 will be described. Two originals 1
When the operator presses the mode switching key 156 to select the double-sided printing mode, the LEDs of the printing mode display means 157 are turned on “double-sided”, and the controller 161 is turned on. And the endless belt 201 is moved in the direction of arrow A in FIG.

Thereafter, when the plate making start key 145 is pressed, the plate cylinder 49 rotates clockwise in FIG.
The printed master on the outer peripheral surface of the plate cylinder 49 is peeled off by the first plate discharging unit 5. Similarly, the plate cylinder 75 rotates counterclockwise in FIG. 5, and the printed master on the outer peripheral surface of the plate cylinder 75 is peeled off by the second plate discharging unit 8.

At the time of the above-mentioned plate discharging, the press roller 4
8 is positioned at the neutral position, and each plate cylinder 49, 75
Contact with has been avoided. Thereafter, each plate cylinder 49, 75
Rotates to a predetermined plate-supply standby position and stops, and a moving means (not shown) operates to position the lower plate discharging members 39 and 69 at the positions shown in FIG. 5, thereby completing the plate discharging operation.

Next, the original conveying roller pair 18 of the image reading section 2 rotates, and the upper one of the two originals 14 and 15 is moved.
The original 14 which is a sheet is conveyed on the contact glass 17 and read. The image of the document 14 read at this time is printed on the back side of the printing paper P. The reading operation is the first
The document 14 is read in the same manner as in the embodiment of FIG.
Is discharged to a document tray (not shown) on the document conveying belt 22.

In parallel with the original reading operation, the first plate making section 4 performs a plate making operation in the same manner as in the first embodiment. After the plate discharging operation is completed, the master 31 pulled out from the master roll 32 by the rotation of the platen roller 34 and the pair of master transport rollers 36 and 37 passes through the thermal head 33, and the surface of the thermoplastic resin film is melt-punched to form a plate. You. When it is determined from the number of steps of a stepping motor (not shown) that rotationally drives the platen roller 34 that the leading end of the master 31 has reached a predetermined position between the stage 51 and the clamper 52, the clamper 52
Is rotated to hold the leading end of the master 31 with the stage section 51. Thereafter, the plate cylinder 49 rotates counterclockwise in FIG. The master 31 is wound on the outer peripheral surface.

If it is determined from the number of steps of a stepping motor (not shown) that plate making for one plate has been completed, the platen roller 34 and the master transport roller pair 3
The rotation of the movable blades 35a is stopped and the movable blade 35a is rotated to cut the master 31. Master 31 disconnected
Is pulled out by the rotation of the plate cylinder 49, and the plate cylinder 49 is again positioned at the home position.

After the positioning of the plate cylinder 49, the original conveying roller pair 18 rotates again, and the remaining original 15 is conveyed on the contact glass 17, and is read in the same manner as described above.
The image of the document 15 read at this time is printed on the front side of the printing paper P. The document 15 from which the image has been read is discharged to a document tray (not shown).

In parallel with the original reading operation, the second plate making section 7 performs a plate making operation in the same manner as the first plate making section 4. After the plate discharging operation is completed, the platen roller 61 and the master transport roller pairs 63 and 64 start rotating, and the master roll 59 is rotated.
The master 58 drawn out of the printer is subjected to plate making when passing through the thermal head 60. And the platen roller 6
When it is determined from the number of steps of a stepping motor (not shown) that drives the motor 1 that the leading end of the master 58 has reached a predetermined position, the opening / closing means (not shown) operates to rotate the clamper 77, and the stage section 76 and the clamper 77
With this, the tip of the master 58 is clamped.

Thereafter, the plate cylinder 75 rotates clockwise in FIG. 5 at the same peripheral speed as the transfer speed of the master 58, and the operation of winding the master 58 around the plate cylinder 75 is performed. And
From the number of steps of a stepping motor not shown, 1
When it is determined that the plate making for the plate has been completed, the rotation of the platen roller 61 and the master transport roller pairs 63 and 64 is stopped, and the movable blade 62a is rotated and the master 58 is cut. The cut master 58 is pulled out by the rotation of the plate cylinder 75, and the plate cylinder 75 is again positioned at the home position.

At the time of the above-described plate feeding, the press roller 48 is positioned at the neutral position, as at the time of plate discharging.
Contact with the plate cylinders 49 and 75 is avoided.

At the same time when the plate feeding operation to each of the plate cylinders 49 and 75 is completed, the paper feed roller 30 is rotated, and the uppermost one of the printing papers P stacked on the paper feed tray 29 is moved to the vertical transport path X.
1 and the plate cylinders 49 and 75 rotate synchronously at low speed.

The paper is separately fed from the paper supply unit 3 and is
1 is sent to each of the bent portions 164a and 164a.
The sheet is guided to the horizontal conveying path Y2 by the guide 5a, and the leading end thereof is added to the pair of registration rollers 172. Thereafter, the printing paper P is fed between the outer peripheral surface of the plate cylinder 49 and the press roller 48 swinging to the first pressing position by rotating the registration roller pair 172 at a predetermined timing. .

The printing paper P fed by the pair of registration rollers 172 has its print image transferred to its first surface (the back surface in a double-sided printed matter) at the contact portion between the plate cylinder 49 and the press roller 48, and The paper conveyor 17 is peeled off from the outer peripheral surface of the plate cylinder 49 by the peeling means 119.
Sent to 3. Suction fan 178 of paper conveyor 173
The printing paper P whose non-printing surface has been sucked on the endless belt 177 by the
It is sent to 63.

The leading end of the printing paper P transported in the direction of arrow A while being held on the endless belt 201 by the suction force of the suction fan 202 and the blowing force of the blower fan 203 is sent to the paper transport means 163. 1 paper detection sensor 2
When the signal 16 is detected, this signal is sent to the control unit 161.

The controller 161 places the entire surface of the printing paper P on the endless belt 201 based on the signal from the paper size detection sensor provided on the paper feed tray 193 and the signal from the first paper detection sensor 216. When it is determined that the driving roller 199 is rotated, an operation signal is sent to a driving unit (not shown) that rotationally drives the driving roller 199. After the driving roller 199 is temporarily stopped, the driving roller 199 is rotated in the opposite direction, and the printing paper P is transported in the direction of arrow B. The reverse operation of the drive roller 199 is performed based on a signal from a sensor (not shown) provided near the outer peripheral surface of the plate cylinder 75, based on the position of the back image of the printing paper P to be sent and the position of the plate cylinder 7.
5 is performed at a timing when the image position of the master 58 wound on the outer peripheral surface of the master 5 matches. At the same time, the rotation direction of the stepping motor 87 is switched, and the swing direction of the press roller 48 is switched.

The second paper detection sensor 204 is a sensor for detecting a jam, and the first paper detection sensor 21
6, after the sheet is detected, the second sheet detection sensor 204
If the sheet cannot be detected in step (1), it is determined that a paper jam has occurred, and a command to that effect is sent from the control unit 161 and the stencil printing machine 158 stops in an emergency.

The printing paper P transported in the direction of arrow B by the paper transporting means 163 is guided by the guide claws 180 and sent again to the paper conveyor 173, and is sucked onto the endless belt 177 by the suction force of the suction fan 179. While the plate cylinder 75
Press roller 4 which swings to the outer peripheral surface of the member and the second pressing position
8 is conveyed.

The printing paper P, on which the print image has been transferred to the second surface (the surface of the double-sided printed material) at the contact portion between the plate cylinder 75 and the press roller 48, is removed by the second peeling means 182.
Thus, the sheet is separated from the outer peripheral surface of the plate cylinder 75 and sent to the sheet discharging and conveying means 183. The printing paper P sent to the paper discharging / conveying means 183 is moved by the suction fan 190 to the endless belt 18.
The sheet is conveyed while being sucked onto the sheet 9, and is discharged to a sheet discharge tray 184. At this time, the printing paper P is discharged such that the image on the second surface side (the image of the second document 15) faces upward. Thereafter, the plate cylinders 49 and 75 rotate to the home position and stop, and the press roller 48 is positioned at the neutral position to complete the plate attaching operation.

Thereafter, test printing is performed in the same manner as in the above embodiment to check the density and position of the printed image.
After various settings are made using the various keys on
When the number of prints is set on the display device 154 at 49 and the print start key 146 is pressed, the printing paper P is continuously sent from the paper supply unit 3 and the printing operation is performed.

Next, the operation at the time of single-sided printing using the stencil printing apparatus 158 will be described. One manuscript (eg manuscript 14)
Is set on the document receiving table 16, and when the mode switching key 156 is pressed by the operator to select the one-sided printing mode, the LED of the printing mode display means 157 is turned on "one-sided" and a signal is sent from the control unit 161. Then, the endless belt 201 is moved in the direction of arrow B in FIG.

Thereafter, when the plate making start key 145 is pressed, the plate cylinder 75 rotates counterclockwise in FIG. 5, and the printed master wound on the outer peripheral surface of the plate cylinder 75 is moved to the second plate discharging section. 8 peeled off.

At the time of the above-mentioned plate discharging, the press roller 4
8 is positioned at the neutral position, and each plate cylinder 49, 75
Contact with has been avoided. The printed master wound on the outer peripheral surface of the plate cylinder 49 is wound as it is without discharging the plate.

Next, the reading operation is performed in the image reading section 2 in the same manner as in the double-side printing, and the master 58 is read by the second plate making section 7.
Plate making operation is performed. The master 58 that has been made is sandwiched between the stage portion 76 and the clamper 77 at the tip thereof, wound around the outer peripheral surface of the plate cylinder 75, and the plate cylinder 75 is again positioned at the home position.

At the same time when the plate cylinder 75 is positioned, the paper feed roller 194 rotates, and the printing paper P1 on the paper feed tray 193 is rotated.
Are guided by the guide plates 195 and 196 to be separated and fed toward the sheet conveying means 163, and the plate cylinder 75 rotates at a low speed.

The leading edge of the printing paper P1 separated and fed from the second paper feeding unit 162 and sent to the paper transporting means 163 is the first paper.
When detected by the paper detection sensor 216, this signal is sent to the control unit 161.

The control unit 161 having received the signal sends an operation signal to a driving means (not shown) for driving the driving roller 199 to rotate, and after temporarily stopping the driving roller 199, rotates the driving roller 199 again to rotate the printing paper P in the direction of arrow B. To be transported. The rotation operation of the drive roller 199 after the temporary stop is performed based on a signal from a sensor (not shown) provided near the outer peripheral surface of the plate cylinder 75, based on the image forming position of the printing paper P1 to be sent and the outer peripheral surface of the plate cylinder 75 This is performed at a timing when the image position of the master 58 wound on the upper side matches.

The printing paper P1 fed by the paper conveying means 163 between the outer peripheral surface of the plate cylinder 75 and the press roller 48 swinging to the second pressing position is fed to the plate cylinder 75, the press roller 48, The printed image is transferred to the second surface at the contact portion of
The sheet 5 is sent to the sheet discharge conveyance means 183 while being peeled from the outer peripheral surface of the sheet 5, and is discharged to the sheet discharge tray 184. Thereafter, the plate cylinder 75 is positioned at the home position and the press roller 48 is positioned at the neutral position, and the plate attaching operation is completed.

After the printing operation is completed, test printing is performed, and after adjusting the density and position of the print image with various keys on the operation panel 144, the print start key 146 is pressed. The printing operation is performed by continuously feeding the printing paper P1.

As described above, the printing time can be shortened by rotating the sheet conveying means 163 forward and reverse during double-sided printing, and unprinted masters are wasted by using only one plate cylinder 75 during single-sided printing. A single-sided printed matter can be obtained without performing.

As another modified example of each of the above embodiments and modified examples, a press roller 205 shown in FIG. Press roller 205
The support shaft 20 is attached to one end of the pair of arm members 206, 206.
5a is rotatably supported, and each arm member 20
A support shaft 207 rotatably supported by the housing 13 is fixed to the other end of each of the shafts 6 and 206. The support shaft 207 is rotated by a stepping motor (not shown) fixed to the housing 13, and outside the one arm member 206, the position of the press roller 205 is detected similarly to the press roller 48 to control the signal thereof. Case 1 that outputs to units 12 and 161
Four sensors (not shown) fixed to 3 are provided. Between each arm member 206, a shaft member 208 that is driven to rotate, a shaft member 209 that can be driven and rotated, and cleaning as a cleaning unit that is rotatable with the outer peripheral surface pressed against the outer peripheral surface of the press roller 205. A roller 210 is provided, and a shaft member 208 includes
The shaft member 2 via the outer peripheral surface of the cleaning roller 210
One end of a smooth nonwoven fabric 211 wound around a roll 09 is wound. The shaft member 208 is rotated by receiving a driving force from a stepping motor (not shown) that rotates the support shaft 207, and is rotated little by little according to the number of prints when the press roller 205 is at the neutral position. Is configured to be wound up. With this configuration, the ink adhered to the peripheral surface of the press roller 205 is transferred to the nonwoven fabric 211 by the pressure contact of the cleaning roller 210, and the outer peripheral surface of the press roller 205 is cleaned. Further, as the cleaning roller 210, a cleaner is supplied to the inside of the support shaft 210a, and the cleaning roller 21 is removed from the surface of the support shaft 210a.
The structure may be such that the cleaner gradually oozes to the surface of the nonwoven fabric 211 and the cleaner is supplied to the surface of the nonwoven fabric 211.

By using the press roller 205, the ink adhered to the surface of the press roller when the printing paper on which the ink was transferred is pressed against the plate cylinder during double-sided printing, or the conveyance failure occurred, and the surface of the press roller was damaged. The adhering matter on the printing paper P,
Retransfer to P1 can be prevented, and the occurrence of printing failure can be prevented.

In each of the above-described embodiments and modified examples, at the time of double-sided printing, the original reading operation is performed from the upper original 14 on the original receiving table 16, and plate making is performed corresponding to the image of the first original 14. The master 31 is wound around the outer peripheral surface of the plate cylinder 49,
A master 58 made in accordance with the image of the next second document 15 is wound around the outer peripheral surface of the plate cylinder 75, and the reverse side of the printing paper P is printed by the plate cylinder 49, and the printing paper P is printed by the plate cylinder 75. Are printed on each surface. However, the present invention is not limited to this.
May be upward or downward, and may be read from either side of the originals 14 and 15 on the original support 16.

[0152]

According to the first and second aspects of the present invention, printing can be performed by selectively using the first plate cylinder and the second plate cylinder.

According to the third aspect of the invention, the transport path switching means switches the transport path of the printing paper to the first paper transport path during double-side printing, and the first plate cylinder is provided on the first surface of the printing paper. After the printing is performed by the pressing member and the pressing member, the conveying path switching unit switches the conveying path of the printing paper to the second paper conveying path, and a second plate cylinder and the pressing member are provided on a second surface of the printing paper. Since printing is performed with the members, printing can be performed on both sides of the printing paper in one pass by using two plate cylinders and one pressing member, and the cost can be reduced and the printing time can be reduced. To perform double-sided printing. Further, at the time of single-sided printing, the transport path switching means is switched to the second paper transport path, and printing is performed on the second surface of the printing paper by the second plate cylinder and the pressing member. A single-sided printed matter can be obtained without consuming it.

According to the fourth aspect of the present invention, at the time of double-sided printing, the transport path switching means switches the transport path of the printing paper to the first paper transport path, and the first plate cylinder is provided on the first surface of the printing paper. After the printing is performed by the pressing member and the pressing member, the conveying path switching unit switches the conveying path of the printing paper to the second paper conveying path, and a second plate cylinder and the pressing member are provided on a second surface of the printing paper. Since printing is performed with the members, printing can be performed on both sides of the printing paper in one pass by using two plate cylinders and one pressing member, and the cost can be reduced and the printing time can be reduced. To perform double-sided printing. Further, at the time of single-sided printing, the transport path switching means is switched to the first paper transport path, and printing is performed on the first surface of the printing paper by the first plate cylinder and the pressing member. A single-sided printed matter can be obtained without consuming it.

According to the fifth aspect of the present invention, excess ink on the printing paper can be removed, thereby preventing retransfer of the ink from the printing paper to the paper conveying means, the pressing member and the like. Thus, it is possible to prevent ink from adhering to the next printing paper, thereby preventing printing failure.

According to the sixth aspect of the present invention, at the time of double-sided printing, after the printing is performed on one surface of the printing paper by the first plate cylinder and the pressing member, the paper transported by transferring the printing paper is performed. The means reverses the conveying direction and conveys the printing paper toward the second plate cylinder, and printing is performed on the other surface of the printing paper by the second plate cylinder and the pressing member. By using one plate cylinder and one pressing member, printing can be performed on both sides of the printing paper in a single pass, and both-side printing can be performed in a short time while suppressing an increase in cost. By using the paper transport means that can be rotated forward and backward, the transport path of the printing paper can be shortened, and double-sided printing can be performed in a shorter time. Further, at the time of one-sided printing, the paper transport means transports the printing paper toward the second plate cylinder, so that printing is performed on the other surface of the printing paper by the second plate cylinder and the pressing member, and the unprinted master is printed. Can be obtained without wasting paper.

According to the seventh aspect of the invention, the ink retransferred from the printing paper to the pressing member can be cleaned, so that the adhesion of the ink from the pressing member to the next printing paper can be prevented, and the printing failure can be prevented. Can be prevented from occurring.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a stencil printing apparatus employing a first embodiment of the present invention.

FIG. 2 is a perspective view illustrating a press roller used in first and second embodiments of the present invention.

FIG. 3 is a diagram for explaining an operation position of a press roller used in the first and second embodiments of the present invention.

FIG. 4 is a diagram showing an operation panel used in the first and second embodiments of the present invention.

FIG. 5 is a schematic side view of a stencil printing machine employing a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a press roller used in another modification of the first and second embodiments of the present invention.

FIG. 7 is a schematic side view of a stencil printing apparatus that employs a modification of the first embodiment of the present invention.

[Explanation of symbols]

 1,158,212 Stencil printing apparatus 3 (First) sheet feeding means 48,205 Pressing member (press roller) 49 First plate cylinder 75 Second plate cylinder 118 Transport path switching means (switching claw) 129 Retransfer Prevention means (drying promotion means) 134, 183 Discharge and conveyance means 156 Mode switching means (mode switching key) 162 Second paper supply means (second paper supply section) 163 Paper conveyance means 210 Cleaning means (cleaning roller) Y 1st paper transport path (horizontal transport path) Z 2nd paper transport path (right angle transport path)

Claims (7)

[Claims] A first plate cylinder, a second plate cylinder opposed to the first plate cylinder, and an outer periphery of each plate cylinder between the first plate cylinder and the second plate cylinder. A stencil printing device, comprising: a pressing member provided to be able to freely contact and separate from the surface. 2. A first plate cylinder, a second plate cylinder opposed to the first plate cylinder, and an outer periphery of each plate cylinder between the first plate cylinder and the second plate cylinder. A pressing member provided so as to be capable of coming and going with respect to a surface; a paper feeding means for feeding printing paper; and a first surface of the printing paper fed from the paper feeding means being a first plate cylinder. A first paper transport path for transporting the printing paper between the outer peripheral surface of the first plate cylinder and the pressing member so as to face the outer peripheral surface; and a second surface of the printing paper. A second sheet transport path for transporting the printing paper between the outer peripheral surface of the second plate cylinder and the pressing member so that the outer surface of the second plate cylinder faces the outer peripheral surface of the second plate cylinder; A stencil printing apparatus comprising: a conveyance path switching unit that selectively switches a conveyance path of a printing sheet to one of a first paper conveyance path and a second paper conveyance path. 3. A first plate cylinder, a second plate cylinder opposed to the first plate cylinder, and an outer periphery of each plate cylinder between the first plate cylinder and the second plate cylinder. A pressing member provided so as to be capable of coming and going with respect to a surface; a paper feeding means for feeding printing paper; and a first surface of the printing paper fed from the paper feeding means being a first plate cylinder. A first paper transport path for transporting the printing paper between the outer peripheral surface of the first plate cylinder and the pressing member so as to face the outer peripheral surface; and a second surface of the printing paper. A second sheet transport path for transporting the printing paper between the outer peripheral surface of the second plate cylinder and the pressing member so that the outer surface of the second plate cylinder faces the outer peripheral surface of the second plate cylinder; Conveyance path switching means for selectively switching the conveyance path of the printing paper to either the first paper conveyance path or the second paper conveyance path; and a duplex printing mode for performing printing on both sides of the printing paper. And a mode switching unit for switching a printing mode to one of a single-sided printing mode for printing only on the second side of the printing paper, wherein a double-sided printing mode is selected by the mode switching unit. Switches the transport path of the printing paper to a first paper transport path by the transport path switching means, and prints on a first surface of the printing paper fed from the paper feeding means by a first plate cylinder. After the printing, the transport path of the printing paper is switched to the second paper transport path by the transport path switching means, and printing is performed on a second surface of the printing paper by a second plate cylinder. When the print mode is selected, the transport path of the printing paper is switched to the second paper transport path by the transport path switching means, and the print paper is fed to the second surface of the print paper fed from the paper feed means. Printing on the second plate cylinder Stencil printing apparatus according to symptoms. 4. A first plate cylinder, a second plate cylinder opposed to the first plate cylinder, and an outer periphery of each plate cylinder between the first plate cylinder and the second plate cylinder. A pressing member provided so as to be capable of coming and going with respect to a surface; a paper feeding means for feeding printing paper; and a first surface of the printing paper fed from the paper feeding means being a first plate cylinder. A first paper transport path for transporting the printing paper between the outer peripheral surface of the first plate cylinder and the pressing member so as to face the outer peripheral surface; and a second surface of the printing paper. A second sheet transport path for transporting the printing paper between the outer peripheral surface of the second plate cylinder and the pressing member so that the outer surface of the second plate cylinder faces the outer peripheral surface of the second plate cylinder; Conveyance path switching means for selectively switching the conveyance path of the printing paper to either the first paper conveyance path or the second paper conveyance path; and a duplex printing mode for performing printing on both sides of the printing paper. And a mode switching unit for switching a printing mode to one of a single-sided printing mode for performing printing on only the first side of the printing paper, wherein a double-sided printing mode is selected by the mode switching unit. Switches the transport path of the printing paper to a first paper transport path by the transport path switching means, and prints on a first surface of the printing paper fed from the paper feeding means by a first plate cylinder. After the printing, the transport path of the printing paper is switched to the second paper transport path by the transport path switching means, and printing is performed on a second surface of the printing paper by a second plate cylinder. When the print mode is selected, the transport path of the printing paper is switched to the first paper transport path by the transport path switching unit, and the first path of the printing paper fed from the paper feeding unit is switched to the first paper transport path. Printing on the first plate cylinder Stencil printing apparatus according to symptoms. 5. A re-transfer prevention means for preventing re-transfer of an image from said printing paper printed by said first plate cylinder in a double-sided printing mode. A stencil printing apparatus as described in the above. 6. A first plate cylinder, a second plate cylinder opposed to the first plate cylinder, and an outer periphery of each plate cylinder between the first plate cylinder and the second plate cylinder. A pressing member provided to be able to freely contact and separate from the surface; a first paper feeding means for feeding printing paper toward the first plate cylinder; and a feeding paper for printing paper toward the second plate cylinder A second sheet feeding means, and a printing sheet provided downstream of the first plate cylinder in the sheet conveying direction and provided between the second sheet feeding means and the second plate cylinder. Paper transport means capable of transporting in the first direction and the second direction, printing in one of a two-sided printing mode in which printing is performed on both sides of the printing paper, and a one-sided printing mode in which printing is performed only on one side of the printing paper And a mode switching means for switching a mode, wherein when the duplex printing mode is selected by the mode switching means, the paper fed from the first paper feeding means is provided. After printing on one surface of the printing paper by the first plate cylinder, the printing paper is sent to the paper transporting means for transporting the printing paper in the first direction, and the printing paper reaches a predetermined position on the paper transporting means. Then, the paper transport direction of the paper transport means is reversed in the second direction to transport the printing paper to the second plate cylinder, and printing is performed on the other surface of the printing paper by the second plate cylinder. When the single-sided printing mode is selected by the mode switching means, the printing paper fed from the second paper feeding means is sent to the paper feeding means for feeding in a second direction,
A stencil printing apparatus, which performs printing with a plate cylinder. 7. The stencil printing apparatus according to claim 1, further comprising cleaning means for cleaning a surface of said pressing member.