JP2000085229A - Stencil printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid an offset of a printing sheet in a size of a shorter length for a thermal stencil base sheet of a small size by lengthening a distance from a press releasing position to a trailing end of the base sheet of the sheet of a small size longer than that of the case of a thermal stencil base sheet of a large size. SOLUTION: A dam element 91 is disposed on an area between a trailing end P1 of an engraving area A and a press releasing position P2. Since the area is pressed to the position P2 after the element 91, ink stored between a master 2 and a mesh screen 27 is wiped by a plate cylinder at the time of printing, dammed up by the element 91, and returned into a printing drum 1 via a mesh screen 2 before the ink is extended from a rear end of the master 2 to an exterior. Accordingly, when the cylinder is released at its pressing at the position P2, an excess amount of the ink of the degree of extending to an exterior is not existed between the master 2 and the screen 27. Therefore, an offset of a printing sheet does not take place in this aspect.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As a prior art disclosed in Japanese Patent Application Laid-Open No. Hei 9-169154, a plate making section for making a roll-shaped heat-sensitive stencil sheet, a cutting section for cutting the heat-sensitive stencil sheet, and a heat-sensitive stencil sheet are disclosed. , A printing drum for supplying ink by wrapping the heat-sensitive stencil sheet around its outer circumference, a printing paper storage section capable of storing printing paper of different sizes, and a printing paper storage section. A paper feed unit for feeding the print paper stored in the print drum unit toward the print drum unit, and a roller-shaped rotating body at the printing pressure unit through the print paper sent by the paper feed unit to form a print drum. Pressing means for pressing the outer peripheral surface in a range covering the plate making area and then releasing the pressure, size detecting means for detecting the size of the printing paper housed in the printing paper housing section, and heat-sensing in the cutting section A control unit for setting at least a cutting timing of the printing plate; and a switching unit for switching a pressing length of the printing paper by the pressing unit in the printing pressure unit, wherein the heat-sensitive stencil is provided in accordance with a size of the printing paper. A screen area capable of cutting the base paper and setting the pressing length of the printing paper, wherein the printing drum allows the ink inside to ooze out through fine openings, and a weir element that does not ooze the ink. And a large-sized heat-sensitive stencil in which the weir element is located between the rear end position of the stencil making area and the pressure release position on the rear end side of the heat-sensitive stencil wrapped around the printing drum. In the case of a stencil sheet, a small sieve in which the weir element is located at a position deviated from the area between the rear end position of the stencil making area and the position for releasing the press And a case of the heat-sensitive stencil sheet is possible stencil printing device.

In such a stencil printing apparatus, a large-sized printing sheet is used because the heat-sensitive stencil sheet is cut in accordance with the size of the printing sheet and the length of pressing of the printing sheet by the pressing means in the printing pressure unit is set. When printing, large-sized heat-sensitive stencil paper is used, and when printing with small-size printing paper, small-sized heat-sensitive stencil paper is used. The heat-sensitive stencil sheet is not wastefully consumed as compared with the case where a fixed large-size heat-sensitive stencil sheet is used regardless of the size of the printing paper.

[0004] Regardless of whether a large-size heat-sensitive stencil sheet is used when performing control with large-size printing paper, or when a small-size heat-sensitive stencil sheet is used when printing with small-size printing paper, Using the same printing drum,
Since the pressing length of the printing paper is switched by the switching means, a printing drum having a different punching range according to the size of the printing paper is prepared as in the related art, and printing is performed according to the size of the printing paper. Compared to replacing the drum, there is an advantage that the operation is not complicated and the burden on the user is reduced in cost.

[0005] On the other hand, in the case of a small-sized heat-sensitive stencil sheet having such advantages, the weir element is located at a rear position outside a region between the rear end position of the plate making region and the position where the pressing means releases the pressing. Therefore, the ink squeezed by the pressing means overflows onto the printing drum behind the heat-sensitive stencil sheet, and the overflowed ink is transferred to the impression cylinder, so-called so-called printing paper to be printed next. There is a problem that back stains occur.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a stencil printing apparatus capable of eliminating the above-mentioned back stain on printing paper.

[0007]

The present invention has the following configuration to achieve the above object. (1). A stencil making section for making a stencil sheet in roll form, a cutting section for cutting the stencil sheet, a stencil feeding section for transporting the stencil sheet, and an ink by wrapping the stencil sheet around its outer periphery. And a printing drum that supplies
A printing paper storage section capable of storing printing papers of different sizes, a paper feeding section for feeding the printing paper stored in the printing paper storage section toward the printing drum section, and a paper feeding section. Pressing means for pressing the roller-shaped rotating body on the outer peripheral surface of the printing drum to the outer peripheral surface of the printing drum in a range covering the plate making area via the sent printing paper, and then releasing the pressing; and the heat-sensitive stencil sheet in the cutting section Control means for setting at least the cutting timing of the printing paper, and switching means for switching a pressing length of the printing paper by the pressing means in the printing pressure unit, and the heat-sensitive stencil sheet according to the size of the printing paper. A screen capable of cutting and setting the pressing length of the printing paper, wherein the printing drum allows the ink inside to ooze out through fine openings. And a weir element that does not allow ink to ooze out, and the rear end side of the heat-sensitive stencil wrapped around the printing drum, between the rear end position of the stencil making area and the pressure release position. And a small-sized heat-sensitive stencil sheet in which the weir element is located at a position outside the area between the rear end position of the stencil making area and the pressure release position. In a stencil printing machine that may be a stencil sheet, the distance from the press release position to the rear end of the stencil sheet is longer than that of the large-size stencil sheet for the small-sized heat-sensitive stencil sheet. Item 1).

(2). A stencil making section for making a stencil sheet in roll form, a cutting section for cutting the stencil sheet,
A stencil feeding section for transporting the heat-sensitive stencil sheet, a printing drum for supplying the ink by winding the heat-sensitive stencil sheet around its outer peripheral surface, a printing paper storage section capable of storing printing paper of different sizes, A paper feed unit that feeds the print paper stored in the print paper storage unit toward the print drum unit, and a roller-like rotating body is driven by the printing pressure unit via the print paper sent by the paper feed unit. Pressing means for pressing the outer peripheral surface of the printing drum in a range covering the plate making area and then releasing the pressing; control means for setting at least a cutting timing of the heat-sensitive stencil sheet in the cutting section; and pressing in the printing pressure section Means for switching the pressing length of the printing paper by means for cutting the heat-sensitive stencil sheet according to the size of the printing paper and pressing the printing paper. The have been made to set of,
The printing drum has a screen area that allows the inside ink to ooze out through a fine opening, and a weir element that does not ooze the ink, and the rear end side of the heat-sensitive stencil paper wound around the printing drum. In the case of a large-sized heat-sensitive stencil sheet in which the weir element is located between the rear end position of the plate making area and the position of the pressure release, and from the rear end position of the plate making area to the pressure release position. In a stencil printing apparatus, which may be a small-size heat-sensitive stencil sheet in which the weir element is located at a position deviated from the area between the stencil elements, the small-size heat-sensitive stencil sheet may be moved from the position where the pressure is released to the position after the base sheet. The distance to the end is 60mm-10
The size was set to be 0 mm (claim 2).

(3). A stencil making section for making a stencil sheet in roll form, a cutting section for cutting the stencil sheet,
A stencil feeding section for transporting the heat-sensitive stencil sheet, a printing drum for supplying the ink by winding the heat-sensitive stencil sheet around its outer peripheral surface, a printing paper storage section capable of storing printing paper of different sizes, A paper feed unit that feeds the print paper stored in the print paper storage unit toward the print drum unit, and a roller-like rotating body is driven by the printing pressure unit via the print paper sent by the paper feed unit. Pressing means for pressing the outer peripheral surface of the printing drum in a range covering the plate making area and then releasing the pressing; control means for setting at least a cutting timing of the heat-sensitive stencil sheet in the cutting section; and pressing in the printing pressure section Means for switching the pressing length of the printing paper by means for cutting the heat-sensitive stencil sheet according to the size of the printing paper and pressing the printing paper. The have been made to set of,
The printing drum has a screen area that allows the inside ink to ooze out through a fine opening, and a weir element that does not ooze the ink, and the rear end side of the heat-sensitive stencil paper wound around the printing drum. In the case of a large-sized heat-sensitive stencil sheet in which the weir element is located between the rear end position of the plate making area and the position of the pressure release, and from the rear end position of the plate making area to the pressure release position. In a stencil printing apparatus that may be a small-sized heat-sensitive stencil sheet such that the weir element is located at a position deviating from the area between the small-sized heat-sensitive stencil sheets, when the number of printed sheets is 250 or less, Alternatively, when the heat-sensitive stencil sheet is replaced every 250 prints, the distance from the position where the pressure is released to the rear end of the sheet is 30 mm to 40 mm. ).

(4). A stencil making section for making a stencil sheet in roll form, a cutting section for cutting the stencil sheet,
A stencil feeding section for transporting the heat-sensitive stencil sheet, a printing drum for supplying the ink by winding the heat-sensitive stencil sheet around its outer peripheral surface, a printing paper storage section capable of storing printing paper of different sizes, A paper feed unit that feeds the print paper stored in the print paper storage unit toward the print drum unit, and a roller-like rotating body is driven by the printing pressure unit via the print paper sent by the paper feed unit. Pressing means for pressing the outer peripheral surface of the printing drum in a range covering the plate making area and then releasing the pressing; control means for setting at least a cutting timing of the heat-sensitive stencil sheet in the cutting section; and pressing in the printing pressure section Means for switching the pressing length of the printing paper by means for cutting the heat-sensitive stencil sheet according to the size of the printing paper and pressing the printing paper. The have been made to set of,
The printing drum has a screen area that allows the inside ink to ooze out through a fine opening, and a weir element that does not ooze the ink, and the rear end side of the heat-sensitive stencil paper wound around the printing drum. In the case of a large-sized heat-sensitive stencil sheet in which the weir element is located between the rear end position of the plate making area and the position of the pressure release, and from the rear end position of the plate making area to the pressure release position. In a stencil printing apparatus, which may be a small-sized heat-sensitive stencil sheet such that the weir element is located at a position deviating from a region between the stencil elements, the control means, in addition to the size of the printing paper,
The timing of cutting the heat-sensitive stencil sheet is set in consideration of at least the information on the number of printed sheets.

(5). (4) The stencil printing machine according to (4), wherein the small-sized heat-sensitive stencil sheet has a printing number of 10
When the number is greater than or equal to 00, the distance from the press release position to the rear end of the base paper is 60 mm to 100 mm. When replacing the paper, the distance from the position where the pressure is released to the rear end of the base paper is 30 m.
The cutting timing for obtaining a base paper size of m to 40 mm is set, and in the case of the large-size heat-sensitive stencil base paper, the distance from the pressing release position to the rear end of the base paper is 15 mm to 20 mm.
mm is set as the cutting timing for obtaining a base paper size of mm.

(6). A stencil making section for making a stencil sheet in roll form, a cutting section for cutting the stencil sheet,
A stencil feeding section for transporting the heat-sensitive stencil sheet, a printing drum for supplying the ink by winding the heat-sensitive stencil sheet around its outer peripheral surface, a printing paper storage section capable of storing printing paper of different sizes, A paper feed unit that feeds the print paper stored in the print paper storage unit toward the print drum unit, and a roller-like rotating body is driven by the printing pressure unit via the print paper sent by the paper feed unit. Pressing means for pressing the outer peripheral surface of the printing drum in a range covering the plate making area and then releasing the pressing; control means for setting at least a cutting timing of the heat-sensitive stencil sheet in the cutting section; and pressing in the printing pressure section Means for switching the pressing length of the printing paper by means for cutting the heat-sensitive stencil sheet according to the size of the printing paper and pressing the printing paper. The have been made to set of,
The printing drum has a screen area that allows the inside ink to ooze out through a fine opening, and a weir element that does not ooze the ink, and the rear end side of the heat-sensitive stencil paper wound around the printing drum. In the case of a large-sized heat-sensitive stencil sheet in which the weir element is located between the rear end position of the plate making area and the position of the pressure release, and from the rear end position of the plate making area to the pressure release position. In a stencil printing apparatus that may be a small-sized heat-sensitive stencil sheet in which the weir element is located at a position deviating from a region between the stencil elements, the rear end of the base sheet from the pressing release position for the small-size heat-sensitive stencil sheet When the distance from the press release position, which is normally set for the large-size heat-sensitive stencil base paper, to the rear end of the base paper is applied to the small-size heat-sensitive stencil base paper, That was predetermined value capable of covering the buttocks leakage area of the ink (claim 6).

(7). (6) In the stencil printing apparatus described in (6), the predetermined value is set to be at least twice the distance from the pressing release position normally set for the large-sized heat-sensitive stencil sheet to the rear end of the stencil sheet.

(8). (6) In the stencil printing machine described in (6), the distance from the pressing release position normally set for the large-sized thermosensitive stencil sheet to the rear end of the stencil sheet is 15 mm
と す る 20 mm, the predetermined value is 1000
When the number of sheets is equal to or greater than 60 mm to 100 mm, and when the number of printed sheets is equal to or less than 250 or when the heat-sensitive stencil sheet is replaced every 250 sheets, the thickness is set to 30 mm to 40 mm.

[0015]

Embodiments of the present invention will be described below. one. Stencil Printing Apparatus Suitable for Implementing the Invention (1) Overall Schematic of Stencil Printing Apparatus FIG. 1 shows an overall schematic of a stencil printing apparatus to which the present invention is applied. In FIG. 1, a printing drum 1 has a cylindrical body having a porous structure, and is configured by winding a mesh screen around the outer periphery of the cylindrical body.

On the outer peripheral portion of the printing drum 1, there is provided a master clamper 12 which is rotatable in parallel with the axis of the printing drum 1. The master clamper 12 is opened and closed at a predetermined position by transmitting a driving force by an opening / closing device (not shown). One end of a heat-sensitive stencil sheet (hereinafter, referred to as a master) 2 is sandwiched by the master clamper 12, and the other end is wound around the outer peripheral surface of the plate cylinder 1.

The master 2 is perforated based on the information of the original in the plate making section 19 located on the right side of the printing drum 1 in FIG. 1, and is conveyed by the base paper feeding section to reach the printing drum 1.
The printing drum 1 is wound around the outer peripheral surface.

A master roll 10 wound in a roll shape is rotatably held in the plate making section 19. The master 2 unwound from the master roll 10 is a thermal head 17
The plate is perforated by being conveyed while being pressed by the platen roller 9 against the heat generating element portion.

Here, the thermal head 17 selectively heats the heating element portion based on an image signal sent from a scanner (not shown) to perform perforation plate making. The rear end side of the master 2 is cut by a cutter 4 as a cutting unit, and is conveyed toward a master clamper 12 of the printing drum 1 by a plate feeding roller 5 as a base paper feeding unit. Eventually,
The master 2 reaches the master clamper 12. The master clamper 12 captures and clamps the tip of the master 2.

After the master clamper 12 clamps the front end of the master 2, the rear end of the master 2 is wound around the outer periphery of the print drum 1 by the rotation of the print drum 1. During this time, perforation by the thermal head 17 is performed as needed. The feed amount of the master 2 is controlled by a platen roller drive pulse motor 6 for driving a platen roller 9, and if a predetermined fixed amount of feed is completed based on a command from a control device (described later with reference to FIG. 5). A cutter drive motor 7 for driving the cutter 4 rotates the eccentric cam 8 to move the cutter 4 and cut the master 2. In this way, the printing drum 1 completes the winding of the master 2 around its outer periphery, thereby completing the plate making and feeding.

A plate discharging device 18 is provided on the left side of the printing drum 1 in FIG. After printing, print drum 1
Used master 2 wound around the printing drum 1
And is stored in the plate discharging device 18.

The printing drum 1 is adapted to be rotated clockwise by a driving device (not shown). Inside the printing drum 1, an ink roller 13 that rotates in synchronization with the printing drum 1 in the same direction,
3 and a doctor roller 15 provided with a slight gap.

A wedge-shaped opposing space formed between the ink roller 13 and the doctor roller 15 forms an ink reservoir 1.
6 is made. The shaft pipe 1 is supplied to the ink reservoir 16.
The ink 14 is supplied from one hole. By the rotation of the ink roller 13 and the doctor roller 15, the ink 14 in the ink pool 16 is supplied to the outer peripheral surface of the ink roller 13. Further, the ink supplied to the outer peripheral surface of the ink roller 13 is supplied to the inner peripheral surface of the printing drum 1 because there is a slight gap between the inner peripheral surface of the printing drum 1 and the outer peripheral surface of the ink roller 13. .

Below the printing drum 1, an ink roller 1 is provided.
Opposite to 3, an impression cylinder 20 composed of a roller-shaped rotating body is located. The impression cylinder 20 has a function of pressing the printing paper 3 against the master 2 on the printing drum 1 at a printing pressure portion which is a position on the outer peripheral surface of the printing drum 1 facing the ink roller 13. Consists of Impression cylinder 20
Instead, a so-called press roller may be used. In the following example, an example of the impression cylinder 20 will be described.

In order to avoid collision with the master clamper 12 on the printing drum 1, the impression cylinder 20 has a part of the outer periphery of the impression cylinder 20 formed with a flat portion.
It has the shape of a shape. A gripper 21 for holding the leading end of the printing paper 3 is provided on the flat portion so as to be freely opened and closed by rotation.

The gripper 21 is opened at a predetermined timing by a cam (not shown), and after the tip of the printing paper 3 is gripped, closed and holds the printing paper 3 on the impression cylinder 20. Discharge claw 2 provided in the vicinity of the outer periphery of 20
At 9, the front end of the printing paper 3 is opened in order to send out the front end of the printing paper 3 to the paper discharging / conveying device 35 through the paper discharging claw 29.

The impression cylinder 20 presses the printing paper 3 in accordance with the size of the printing paper 3.
One end side is supported by a fulcrum shaft 24 as means for controlling the timing of pressing and separating the impression cylinder 20 so that the printing paper 3 is not pressed at a portion where the printing paper 3 is not present. 24, and the impression cylinder 20 is rotatably supported on the free end side of the swing arm 25.
The oscillating arm 25 is oscillated at predetermined timing by cams 54 and 54 ′ (described later with reference to FIGS. 2 and 4) which rotate in synchronization with the printing drum 1 to press the impression cylinder 20 against the printing drum 1 The printing paper 3 is pressed only when necessary.

The means for pressing the impression cylinder 20 against the printing paper 3 at the printing pressure section and separating the impression paper 20 from each other is referred to as pressing means. The pressing means is constituted by a swing arm 25, a pressing spring 26 which is an elastic spring, the cam, the impression cylinder 20, and the like. The swing arm 25, the pressing spring 26, and the cam are not shown in FIG.
The same member is provided on the opposite side of FIG.

Further, when a transport error occurs, the impression cylinder 20 is not pressed against the printing drum 1 and is released by a printing pressure release device (not shown). The cam 5
4, 54 'have a number of cam surfaces corresponding to the type of pressing length of the printing paper by the impression cylinder 20. This cam surface is switched according to the size of the printing paper. This switching means will be described later.

In FIG. 1, on the lower left side of the printing drum 1, a paper ejection claw 29 for peeling the printing paper 3 after printing (after ink application) from the impression cylinder 20 is provided near the outer peripheral surface of the impression cylinder 20.
And a paper discharge transport device 35 that transports the separated printing paper 3
And a paper discharge table 36 for storing the printing paper 3 conveyed by the paper discharge conveyance device 35.

In FIG. 1, a printing paper storage section is provided at the lower right of the printing drum 1 and includes an elevator type paper feeding table 31 capable of storing printing papers of different sizes. The paper feed table 31 has an optical sensor 4 serving as a size detecting means for detecting the size of the stored printing paper.
0, an optical sensor 41 is provided.

The optical sensor 40 is arranged at a position where the leading end of the printing paper can be detected, and the optical sensor 41 is arranged at a predetermined interval behind the optical sensor 40 in the transport direction. Thereby, the size of the stored printing paper can be identified by the case where only the optical sensor 40 detects the presence of the printing paper and the case where the optical sensor 40 and the optical sensor 41 detect the presence of the printing paper. .

The paper feed table 31 is moved up and down by a driving device (not shown) while the top of the loaded print papers 3 is always held by the call roller 30 so as to be given an appropriate pressing force capable of being conveyed. It is supposed to be.

The paper feed unit has a paper feed roller 32 rotatably supported and a call roller 30, and these rollers are connected by an endless belt (not shown). Below the paper feed roller 32, a separation roller 34 for preventing double feeding of the printing paper 3 is pressed. Further, a pair of feed rollers 33 rotatably supported and a pair of guide plates 38 for guiding the print paper 3 to the feed roller nip are provided in front of the print paper transport direction.

The paper feed roller 32 is rotated clockwise by a cam (not shown) rotating in synchronization with the print drum 1, a sector gear having a cam follower engaged with the cam, and a paper feed roller gear incorporating a one-way clutch. Is rotated. Similarly, the feed roller 33 has a cam roller (not shown) rotating in synchronization with the print drum 1, a sector gear having a cam follower engaged with the cam, a feed roller gear incorporating a one-way clutch, and the like. Rotated clockwise. The feed speed of the printing paper 3 by the feed roller 33 is set to be equal to the peripheral speed of the printing drum 1.

(2) Procedure for transporting print paper The print paper 3 sent out by the rotation of the paper feed roller 32 and the call roller 30 is fed to the paper feed roller 32 and the separation roller 34.
The double feed is prevented at the portion, and only the uppermost sheet is fed to the feed roller 33. When the leading end of the printing paper 3 collides with the nip portion between the feed rollers 33 and the paper is further fed from behind, a predetermined amount of slack is formed upward. At the time when the curved slack is formed, the feed roller 32 and the call roller 30 stop rotating.

Thereafter, the feed roller 33 is rotated at a predetermined timing at which the master 2 on the printing drum 1 and the printing paper 3 can be matched by the cam to eliminate the slack of the printing paper 3. Further, the paper feed roller 32 and the retrieving roller 30 which incorporate a one-way clutch and are rotatable in the paper transport direction are also driven to rotate by the transport of the print paper 3, and the print paper 3 is transported toward the impression cylinder 20. . In accordance with this timing, the gripper 21 in the impression cylinder 20 is opened, and after the printing paper 3 is gripped, the gripper 21 is closed and the impression cylinder 2 is held while the printing paper 3 is held by the impression cylinder 20.
0 rotates, and the printing paper 3 is fed to the nip portion between the printing drum 1 and the impression cylinder 20, that is, the printing pressure portion.

When the printing paper 3 is sent to the printing pressure section in this manner, the impression cylinder 20 is pressurized by the force of the compressive pressing spring 26, and the printing paper 3 is transferred via the master 2 to the outer periphery of the printing drum 1. Pressed against the surface. During this pressing,
The ink that has passed through the fine opening formed in the outer peripheral surface of the printing drum 1 and the perforated portion of the master 2 attached to the outer peripheral surface is transferred to the printing paper 3 by the ink roller 13 and printing is performed.

The printing paper 3 on which the ink has been transferred is held by the gripper 2 before the discharge nail 29 after the impression cylinder 20 is further rotated.
When the sheet 1 is opened, the sheet 1 is peeled off from the leading end by the sheet discharge claw 29, is conveyed to the sheet discharge table 36 by the sheet discharge conveyance device 35, is stacked on the sheet discharge table 36, and printing is completed.

(3) Master cutting length setting means, printing paper pressing length switching means This will be described with reference to FIGS. 1 to 6. The impression cylinder 20 is formed integrally with its central axis 23 and central axis 23 '. These central shafts 23, 23 'protrude on both sides in the axial direction of the impression cylinder 20, and the protruding portions are supported at intermediate positions of the swing arms 25, 25' via bearings 50, 50 '. . Thereby, the impression cylinder 20 is moved to the swing arms 25 and 25 '.
It is rotatable with respect to.

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

Each fulcrum shaft 24 of the swing arm 25, 25 '
On one side opposite to 24 ', that is, on the free end side, one end of each of the pressing springs 26 and 26' made of an elastic spring is hung, and the other end is hung on a stationary member. Therefore, due to the elasticity of the pressing springs 26, 26 ', the swinging arms 25, 25' rotate the impression cylinder 20 in the direction toward the front side perpendicular to the plane of the drawing about the fulcrum shafts 24, 24 'in FIG. A rotational force in the direction in which it is caused is given. That is, the pressing springs 26 and 26 ′ apply the rotational moment in the direction of pressing the impression cylinder 20 to the printing drum 1 by the swing arms 25 and 2.
5 '.

A fulcrum shaft 24 'penetrating the swing arm 25'
A gear 57 is integrally attached to one end of the gear shaft. The gear 57 is meshed with a gear 58 integrally attached to the central shaft 23 '. The fulcrum shaft 24 'penetrating the rear plate 52' is connected to a support frame 80 provided outside the rear plate 52 '.
Of the bearing 55 '. These bearings 55, 5
A pulley 56 is fixed to the fulcrum shaft 24 'between the shafts 5'. A belt stretched between the pulley 56 and a drive source (not shown) rotates the impression cylinder 20 at the same linear speed as the printing drum 1. It is supposed to be.

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

The cams 54, 54 'are both fixed to a shaft 60. The cam 54 has an integral structure having cam plates 54a and 54b having different cam surfaces.
, The cam plate 54b is located to the right of the cam plate 54a. Similarly, the cam 54 'includes cam plates 54a' and 54b '.
And the cam plate 54b 'is located to the right of the cam plate 54a'. The cam plate 54a and the cam plate 54a 'have the same size and shape. Also, the cam plate 54b and the cam plate 54b '
And have the same size and shape.

The cam plate 54a and the cam plate 54a 'are "A4
Impression cylinder 2 for printing paper up to "landscape" size (see FIG. 6)
Compatible with zero pressure control. Also, the cam plates 54b, 54b '
Is suitable for controlling the pressure of the impression cylinder 20 on the printing paper exceeding the “A4 horizontal” size to the “A3 vertical” size (see FIG. 6).

The shaft 60 integrally formed with the cams 54 and 54 'is connected to the front side plate 52 via a bearing 65,
Also, the rear side plate 52 'is rotatable via a bearing 65', and
It is slidably supported in the longitudinal direction of the shaft. Bearing 65, 6
5 'is fixed to each side plate 52, 52' with a screw 85 so that the shaft 60 does not shift even if it slides.

A gear 66 is fixed to a portion of the shaft 60 protruding from the bearing 65 '. This gear 66 has a gear 6
The gear 66 'is connected to a drive system (not shown), and the shaft 60 is rotated in synchronization with the rotation of the printing drum 1 by power transmission from the drive system. .

The shaft 60 is slidable in the longitudinal direction of the shaft as described above, and the cam followers 53, 5
The state in which the cam plates 54a, 54a 'abut against the 3' and the cam plates 54b,
54b 'can be switched to the state in which it abuts.

FIG. 2 shows a state in which the cam plates 54a and 54a 'are in contact with the cam followers 53 and 53'. The movement stroke of the shaft 60 is equal to the distance between the cam plates 54a and 54b, and the switching between the cam plates 54a and 54a 'and the cam plates 54b and 54b' may be performed by this stroke. In order to ensure rotation of the shaft 60 even when the shaft 60 slides, the thickness of the gear 66 is set to a size corresponding to the movement stroke.

As shown in FIG. 2 and FIG.
A bearing cover 67 is mounted on a shaft end protruding from 5 through a bearing 68. The bearing 68 rotatably supports the shaft 60, and abuts against the shaft end of the shaft 60 so that the shaft 60 can rotate.
Can be slid in the longitudinal direction of the shaft.

One end of the swing arm 63 is pivotally connected to the bearing cover 67 by a shaft 70. An intermediate portion of the swing arm 63 is supported by a support member 8 integrated with the front side plate 52 via a shaft 64.
It is pivoted to 1. The other end of the swing arm 63 is pivotally attached to a plunger of a solenoid 82 fixed to a stationary member. An extensible spring 69 is provided between the bearing 65 and the bearing 68 so as to loosely wind the shaft 60.
A stopper 71 is fixed on the shaft 60 between the front side plate 52 and the swing arm 25.

When the solenoid 82 is turned off, the shaft 60 is urged leftward in FIG. The movement of the shaft 60 due to this bias is performed by the stopper 71.
Abuts against the bearing 65 or is blocked by the bearing cover 67. When the solenoid 82 is turned on, the shaft 60
2 to the right as shown in FIG. 2 against the elasticity of the spring 69, and the cam plates 54a and 54a '
3 ′.

On the other hand, when the solenoid 82 is turned off, it is possible to make the plunger of the solenoid 82 project by the force of the spring 69. Therefore, when the solenoid 82 is turned off, the shaft 60 moves leftward from the position shown in FIG. 2 and stops at the position where the stopper 71 contacts the bearing 65. In this stop position, the cam plates 54b and 54b 'come into contact with the cam followers 53 and 53'.

Therefore, in this configuration, the cam plates 54a, 54a 'are brought into contact with the cam followers 53, 53' in accordance with the on / off control of the solenoid 82, or the cam plates 54b, 54b,
54b 'can be switched to abut.
The solenoid 82 constitutes switching means for switching the length of pressing of the printing paper by the pressing means.

On the other hand, the method of switching the cutting length of the master is as follows.
By controlling the start and stop of the platen roller drive pulse motor 6 and the cutter drive motor 7, the length of the master 2 can be cut in accordance with the length of the printing paper.

The start / stop control of the platen roller drive pulse motor 6 and the cutter drive motor 7 and the ON / OFF control of the solenoid 82 are performed by controlling the outputs from the optical sensors 40 and 41 as shown in FIG. This is performed according to a command based on a predetermined program of the control means 84 which is input. Thus, the arrangement of the optical sensors 40 and 41 for detecting the size of the printing paper, which is the basis for such control, will be described.

(4) Arrangement of Optical Sensors in Paper Feeding Table In FIG. 6, the storage of the printing paper on the paper feeding board 31 is performed by aligning the edge of the printing paper with the left end of the paper feeding board 31 and It is assumed that the printing paper is stored on a so-called center reference where the center of the printing paper is aligned with the center of the base 31, and the transport direction of the printing paper is indicated by a white arrow. On this paper feed table 31, printing paper of A6 size to A3 size can be placed.

In FIG. 6, the “A6 portrait” size is an arrangement mode when the A6 size printing paper is arranged so that the longitudinal direction and the transport direction are matched, and the “A4 landscape” size is the size of the A4 size. This is an arrangement mode when the printing paper is arranged with its short side direction and the conveying direction matched.

According to such a display direction, the sheet feeding table 3
1, "A6 portrait", "A4 landscape", "B5 portrait", "A
It is possible to arrange the printing papers of six sizes of “4 portraits”, “B4 portraits” and “A3 portraits”. In this example, the optical sensor 40 is provided near the left end of the paper feed table 31. Also, the optical sensor 41 is set to A4, which is a dimension A4 horizontal from the left end of the sheet feeding table 31.
It is located outside the position h and inside the position B5v, which is the vertical dimension of B5 from the left end of the paper feed table 31.

By arranging the optical sensors 40 and 41 in this manner, only the optical sensor 40 detects the presence of the printing paper regardless of whether the size of the printing paper is "A6 portrait" or "A4 landscape". At this time, it is determined that the printer is in the “A4 landscape” size storage state, and the printing paper is “B5 portrait”, “A4 portrait”,
Regardless of the size of “B4 portrait” or “A3 portrait”, when both the optical sensor 40 and the optical sensor 41 detect the presence of the printing paper, it is determined that the “A3 portrait” size is stored. Thus, the cutting length of the master and the pressing length of the impression cylinder can be controlled.

In this embodiment, the cutting length of the master and the pressing length of the impression cylinder are controlled in two stages, and the cams 54, 5
4 'has two cam plates 54a and 54b and two cam plates 54a' and 54b '. The pressing length is controlled by the pair of cam plates 54a and 54a' and the pair of cam plates 54b and 54b '. It is possible to control the controlled pressing length in two stages.

That is, the cam plates 54a and 54a 'have a cam surface which enables a uniform pressing length when the printing paper is of "A6 portrait" and "A4 landscape".
b, 54b 'indicate that the printing paper is "B5 portrait", "A4 portrait",
It has a cam surface that enables a uniform pressing length for each of the “B4 portrait” and “A3 portrait” sizes.

In this example, the cutting length of the master and the pressing length of the impression cylinder are divided into two stages. However, by increasing the number of locations where the optical sensors are arranged and providing a cam corresponding thereto, the size of the printing paper can be finer. It is possible to set the cutting length of the master and the pressing length of the impression cylinder in accordance with the conditions. In addition to the method of automatically setting the cutting length of the master and the pressing length of the impression cylinder based on the information from the optical sensor as described above, the operator operates keys provided on the operation panel 96 shown in FIG. It is also possible to set the cutting length of the master or the pressing length of the impression cylinder by inputting a large size or a small size.

(5) Structure of the Printing Drum Peripheral Surface The printing drum 1 has a cylindrical shape, the circumferential surface of which is made of a thin metal plate, and a certain range excluding the portion where the master clamper 12 is provided. 0.5m for transmission
An opening is formed in which countless small holes having a diameter of m are formed. A mesh screen 27 as indicated by reference numeral 27 in FIG. 7 is provided so as to cover the opening.

As shown in FIG. 7A, the mesh screen 27 has a back screen 27a and a front screen 27b.
Of two screens. As shown in FIG. 8, one end of the front screen 27b is connected to the front stay 9
0 is wound once, and is adhered to each other by an adhesive at an adhesive portion 91 'sandwiching one end of the back screen 27a. The front stay 90 is formed in a ring shape. In the shape. Also, the other end of the front screen 27b is formed into a ring shape by winding the rear stay 92 once and then being bonded to each other with an adhesive at the bonding portion 91, and the rear stay 92 penetrates the ring-shaped portion. are doing.

In FIGS. 7B and 7C, for convenience of explanation,
The front stay 90 and the rear stay 92 are shown in an enlarged state in a state where they are pulled out from the respective ring-shaped portions. As shown in FIG. 7B, a mounting hole 90a is formed at one end in the longitudinal direction of the front stay 90, and the other end of the front stay 90 is similarly formed as shown in FIG. Mounting hole 90
a 'is formed.

Similarly, as shown in FIG. 7C, one end of the rear stay 92 in the longitudinal direction is provided with a mounting recess 92a.
A notch 92a 'for attachment is formed at the other end of the stay 92 (not shown).

As shown in FIGS. 9 (a), 9 (b) and 9 (c), the front stay 90 and the rear stay 92 are provided with mounting holes 90a and 90a 'and mounting recesses 92a and 92a. ', The screws 93, 94, 9 for mounting on the mounting seat (not shown) of the printing drum 1.
5, 96 are fixed. Thus, the mesh screen 27 is configured so as to cover the outer peripheral surface of the printing drum 1 in close contact therewith.

Here, the portions of the bonding portions 91 and 91 'are in a state where the mesh of the mesh screen 27 is crushed by the adhesive and the ink does not pass therethrough. Bonding parts 91 and 9
1 ', the ink that has been squeezed by the impression cylinder 20 during printing is particularly upstream of the adhesive portion 91, which is located on the downstream side (also referred to as the rear end side) in the rotation direction of the printing drum 1. The adhesive portion 91 is hereinafter referred to as a weir element 91 because it is blocked at the end on the side.

(6) Examples of Claims 1 to 8 FIGS. 10A and 10B show a state in which a part of the printing drum 1 is partially developed in the winding direction of the printing paper. FIG.
3A and 3B show a state where the master 2 and the master 2 ′ are mounted on the mesh screen 27. The tip of master 2 or master 2 'is the master clamper 1.
2. The length of the opening portion of the printing drum 1 is indicated by reference symbol C.

FIG. 10A shows the maximum size of A3 size paper that can be printed by the print drum 1 as “A3 size”.
FIG. 9 illustrates the relationship between the cutting length of the master and the pressing length of the impression cylinder, which are executed when the sheets are stored in the “vertical” size arrangement mode. The entire length of the master 2 is indicated by a symbol D, and the length is cut so that printing is performed properly in conformity with “A3 portrait” printing paper. The cut end of the master 2 is held by the master clamper 12, and the rear end of the master 2 is located on the weir element 91.

The master making area A (410 mm in length in this example) of the master 2 has an opening C and a mesh screen 27.
Is set so as to overlap the position. Further, margins G and H are provided before and after the plate making area A so that the entire area of the plate making area A is surely pressed, and the impression cylinder 20 presses including these areas of the margins G and H. The pressing length B (430 mm in this example) is set as described above. Margin G
Is an arbitrary value in the range of 5 to 6 mm (5 m in this example).
m) and the allowance H are set to arbitrary values (15 mm in this example) within the range of 10 to 20 mm.

Further, regarding the master 2, the printing drum 1
In the rotation direction, the portion on the upstream side of the region of the pressing length B is a front margin E (80 mm in this example), and the portion on the downstream side of the region of the pressing length B is a rear margin F = 15 to 20 mm (book). 20 mm in the example). Here, the rear end P1 of the plate making area A is a position in front of the weir element 91 and in the area of the mesh screen 27, and the pressing release position P2 by the impression cylinder 20 and the rear end P3 of the master 2 are respectively the weir element 91 Located on top. Therefore, the weir element 91 is located in a region between the rear end P1 of the plate making region A and the pressure release position P2.

Since the ink is pressed to the pressing release position P2 after the weir element 91, the ink that has been squeezed by the impression cylinder 20 and accumulated between the master 2 and the mesh screen 27 during printing is blocked by the weir element 91. Then, the printing paper 1 returns to the inside of the printing drum 1 through the mesh screen 27 before protruding from the rear end of the master 2 to the outside. Therefore, when the impression cylinder 20 releases the pressing at the pressing release position P2, there is no excess amount of ink between the master 2 and the mesh screen 27 that protrudes outside. Therefore,
In this case, no back stain on the printing paper occurs.

In the case shown in FIG. 10A, the optical sensors 40 and 41 described in FIG. 6 read the size and arrangement of the printing paper set on the paper feed table 31 by the operator according to the size and arrangement of the original. The reading means outputs the platen roller driving pulse motor 6 and the cutter driving motor 7 so that the control means 84 shown in FIG. 5 can obtain a master size suitable for the size of the printing paper.
To control the master to cut the master total length D
Master 2 is obtained.

The total length D of the master 2 is the pressing length B = 43.
0mm at the front margin E = 80mm and the rear margin F = 20mm
And about 530 mm. At the time of printing, the control means 84 controls the solenoid 82 so that the cam plate 54
b, 54b 'are brought into contact with the cam followers 53, 53' so that the impression cylinder 20 presses the front margin E = 80 mm, the pressing length B = 430 mm, and the rear margin F = 20 mm.

On the other hand, in the case shown in FIG. 10B, the printing paper is small-size paper and the A4 size is changed to “A”.
4 illustrates the relationship between the cutting length of the master and the pressing length of the impression cylinder, which are executed when the sheets are stored in the "4 landscape" mode. FIG.
In (b), the master 2 'has a full length D' cut so as to be compatible with "A4 landscape" printing paper. The master 2 'mounted on the printing drum 1 is held at its leading end by the master clamper 12, and has a plate making area A' (200 m long in this example).
m) is set so as to be located at a position overlapping with the opening C and the mesh screen 27. Further, the same margin G (5 mm in this example) and H (15 m in this example) as in FIG. 10A before and after so as to cover the plate making area A ′.
m), the pressing length B ′ (220 mm in this example) is set. In addition, in the portion of the master 2 'in the rotation direction of the printing drum 1 and upstream of the region of the pressing length B', the leading end margin E (in this example, the same value as the master 2 in FIG. 80 mm).

Here, assuming that the value of the rear end margin F ', which is a section downstream of the pressing length B' and from the pressing release position P2 'to the rear end P3' of the master 2 ', is the value shown in FIG. Assuming that 20 mm is taken in the same manner as in the case shown in FIG. 7, the rear end P3 'of the master 2' is located at a position in front of the weir element 91 and at a position separated from the weir element 91. When there is no dam element 91 in the release position P2, the ink is not dammed and the ink cannot be returned into the print drum 1, and when the impression cylinder 20 presses the master 2 'within the pressing length B', FIG. As shown in the enlarged view of FIG. 3C, the ink is changed to the mesh screen 27 while printing is repeatedly performed.
In the end, the ink leaks to the rear end side from the pressure release position P2 ', and as shown by reference numeral 94, so-called bottom leakage occurs due to the ink.

The relationship of the trailing end side of the master 2 ′ covers the area of the trailing edge 94, that is, if the trailing margin F ′ is larger than the trailing edge 94, the trailing edge 94 does not protrude from the master 2 ′. However, if the trailing margin F 'is smaller than the trailing edge 94, the trailing edge 94 protrudes to the rear side of the master 2'. FIG. 11 shows a state in which the trailing edge 94 protrudes to the rear side of the master 2 '.

As shown in FIG. 11, when the trailing edge 94 protrudes outside the master 2 ', it is transferred to the surface of the impression cylinder 20 in the next printing step, and the surface of the impression cylinder 20 is stained with ink. The stain 20 is transferred to the back surface of the printing paper thereafter, causing the stain on the back side. This must be avoided. The following experiment was performed in order to obtain a guideline for setting the trailing margin F 'so that the trailing edge 94 would not be outside the master 2'. [Experiment conditions] Number of continuous prints 10, 100, 250
Sheets, 500 sheets, 1000 sheets, and 5000 sheets, the temperature of the environment where the stencil printing machine was placed was 30 ° C., 2
Press release position P2 'for each of 3 ° C and 5 ° C
The length K (see FIGS. 10 (a) and 11) from the bottom to the rear end 94 was measured. In addition, the flow value of the ink at each temperature was measured according to JIS-K-5701. Table 1
In addition, the measured value (unit:
mm). The flow value is a value obtained by measuring the diameter of the ink one minute after pressurization using a spreadmeter. Various dimensions of printing drum 1, masters 2 and 2 ', impression cylinder 20
The pressing conditions and the like depend on the conditions described with reference to FIGS. 10 (a) and 10 (b). The environmental temperature covers 5 to 30 ° C., which is considered to cover almost the normal environmental temperature throughout the four seasons.

[0082]

[Table 1]

(I) Claim 1 As can be seen from Table 1, the length of the buttocks leakage K is at most 53 mm.
As shown in FIG. 10B, a small-sized master 2 'such as "A4" in which the weir element 91 is not located between the rear end P3' of the master 2 'and the pressing release position P2' as shown in FIG.
In the case of “landscape” size, if the rear end margin F ′ is set to an arbitrary value exceeding 53 mm, the number of printed sheets is 5,000 and the environmental temperature is 5
Even under the worst condition in the range of the experiment of ° C, no back stain occurs.

Here, the value of the trailing margin F 'exceeding 53 mm is defined as the trailing edge P of the master 2 as shown in FIG.
3 has a weir element 91 between the pressure release position P2 and the large-size master 2, for example, the rear end margin F = 15 to 20 mm in the case of “A3 portrait” size (20 m in this example).
clearly larger than in case m).

Also, the rear end margin F 'is 1 which is a limit value when the rear end margin F of the large size is larger than 15 mm.
Even at 6 mm, as can be seen from Table 1, up to 5000 sheets at an ambient temperature of 30 ° C. and 5 at an ambient temperature of 23 ° C.
Under the conditions of up to 00 sheets and up to 100 sheets at an environmental temperature of 5 ° C., the trailing margin F ′ = 16 mm can sufficiently cover the area of the trailing edge, so that the back side of the printing paper can be covered. Does not generate dirt.

This is not limited to the case where the master 2 ′ has the “A4 landscape” size, and the weir element is located at a position outside the area from the rear end position of the plate making area to the pressure release position. It can be empirically said that it is suitable for small masters in general.

(Ii) Regarding Claim 2 Assuming conditions slightly more severe than the environmental temperature of 5 ° C. to 30 ° C. under the experimental conditions in Table 1, or variations in the trailing edge length K during actual printing, etc. In consideration of the above, a margin value is added to the maximum value 53 mm of the length K of the buttocks in Table 1,
An example in which the rear end margin F 'is set to about 60 to 100 mm can be adopted. Within this range, back stains do not occur on the printing paper empirically under all use conditions.

This means that “A4 side” is used as the master 2 ′.
It can be empirically found that the present invention is applicable not only to the case where the damper element is used but also to a small-sized master in which the weir element is located at a position outside the region between the rear end position of the plate making region and the position where the pressure is released. .

(Iii) Claim 3 According to Table 1, the ambient temperature is 5 ° C. and the number of printed sheets is 250.
When the number of printed sheets is 250 sheets or less, or when the master 2 'is replaced every 250 printed sheets, the margin is appropriately determined in consideration of the above-mentioned 21 mm variation since the length of the trailing edge K is 21 mm. , And add a trailing margin F ′ of 30 to 40.
mm, it is possible to avoid back stains on the printing paper.

This means that “A4 side” is used as the master 2 ′.
It can be empirically found that the present invention is applicable not only to the case where the damper element is used but also to a small-sized master in which the weir element is located at a position outside the region between the rear end position of the plate making region and the position where the pressure is released. . (Claim 3).

(Iv) Claims 6 and 7 For the master 2 ′, a predetermined value of the trailing margin F ′ that can cover the length K of the trailing edge (tail trailing area) is set based on Table 1. And As the predetermined value, 20 mm out of 15 to 20 mm, which is a normally set rear end margin for a large-size master 2 in which a weir element is located between the rear end position of the plate making area and the position where the pressure is released, is set. When adopted, the value is set to be at least twice this value, that is, at least 40 mm, so that up to 500 sheets can be printed at all environmental temperatures (30 ° C., 23 ° C., and 50 ° C.). Can be avoided.

Further, from Table 1, the rear end margin normally set for a large-size master 2 in which the weir element is located between the rear end position of the plate making area and the position where the pressing is released is F =
When the value is 15 to 20 mm, the predetermined value is 60 to 100 mm and the number of prints is 250 when the number of prints is 1000 or more.
When the master 2 ′ is replaced when the number of printed sheets is equal to or less than 250 or when the number of printed sheets is 250, if the predetermined value is 30 to 40 mm,
As a result, the trailing edge of the master 2 'covers the trailing area,
It is possible to avoid back stains on the printing paper.

The above description means that the large-size master is the “A3 vertical” master 2 and the small-size master is the “A4 vertical” master.
Not only in the case of the “master” 2 ′, but also in the large master where the weir element is located in the area from the rear end position of the plate making area to the position where the pressing is released, and the position where the pressing is released from the rear end position of the plate making area It can be empirically shown that the present invention can be applied to a small-sized master in which the weir element is located at a position deviating from the region between the two.

(V) Claims 4 and 5 In the case shown in FIG. 10A, the size (A3 portrait) of the printing paper set on the paper feed table 31 by the operator in accordance with the original has been described with reference to FIG. The optical sensors 40 and 41 read. The read output is input to the control means 84 shown in FIG. 5, and the control means 84 controls the platen roller drive pulse motor 6 and the cutter drive motor 7 so that the size of the master is adjusted to the size of the printing paper. Is cut to obtain a master 2 having a total length D. Further, the control means 84 controls the pressing length B = 430 m by the impression cylinder 20.
m, the solenoid 82 is controlled to move the cam plates 54 b and 54 b ′ to a position where the cam plates 54 b and 54 b ′ abut on the cam follower 53 in order to perform pressing with the front margin E = 80 mm and the rear margin F = 20 mm. Thus, the timing of pressing the impression cylinder 20 against the master 2 is set by the cam plates 54b and 54b '.

In the case shown in FIG. 10B, the size (A4 width) of the printing paper set on the paper feed tray 31 by the operator according to the original is determined by the optical sensor 4 described in FIG.
0 and 41 are read. This read output is input to the control means 84 shown in FIG. Also, as shown in FIG.
The number-of-printed-sheets information input to the operation panel 96 by the operator during printing is input to the control means 84.

The control means 84 determines the size of the printing paper (A4
From the width) and the number of prints, the minimum rear margin F that can cover the trailing edge area that may occur under given conditions according to a predetermined procedure based on the experimental results in Table 1 above. And the total length D 'of the master 2' is calculated, and in order to obtain the master 2 'of this length, the platen roller drive pulse motor 6 and the cutter drive motor 7 are controlled to cut the master and the master 2' Get '. Further control means 84
Controls the solenoid 82 to perform the pressing by the impression cylinder 20 at an appropriate value that can cover the trailing edge area as the pressing length B ′ = 220 mm, the front margin E = 80 mm, and the rear margin F ′. , 54a 'to the cam followers 53, 5
Move to the position where it contacts 3 '. Thus, the cam plate 54
The timing of pressing the impression cylinder 20 against the master 2 'is set by a and 54a'. As a result, the ink does not leak out of the master 2 ', and the back stain on the printing paper due to the trailing edge does not occur.

For a small-sized master in which the weir element is located at a position outside the area between the rear end position of the plate making area and the position where the pressure is released, the value of the rear end margin F 'according to the number of prints is set. To illustrate, based on Table 1 above, for example,
In the case of the “A4 landscape” size master 2 ′,
For more than 000 sheets, the trailing margin F 'is 60 to 100 m
m, when the number of prints is 250 or less or when the master 2 'is replaced every 250 prints, the trailing margin F' is 30
The total length D ′ is determined so as to be ４０40 mm, and the cutting timing of the cutter 4 is set. Further, in the case of a large-size master in which the weir element is located between the rear end position of the plate making area and the position where the pressing is released, for example, in the case of the master 2 of “A3 portrait” size, the rear end margin F is The cutting timing of the cutter 4 is controlled so as to obtain a master full length D of 15 to 20 mm.

[0098]

According to the first and second aspects of the present invention, a small-sized heat-sensitive stencil in which the weir element is located at a position outside the region between the rear end position of the plate-making region and the position where the pressure is released. With regard to the base paper, it is possible to avoid back stains on the printing paper due to so-called trailing edges with a shorter length.

According to the third, fourth, and fifth aspects of the present invention, a small-sized heat-sensitive stencil in which the weir element is located at a position outside the region between the rear end position of the plate-making region and the position where the pressure is released. In accordance with the predetermined number of printed sheets of the base paper, it is possible to avoid back stains on the printing paper due to so-called trailing edges with a shorter length.

According to the sixth and seventh aspects of the invention, a so-called heat-sensitive stencil sheet having a large size in which the weir element is located in a region between the rear end position of the plate making region and the position where the pressure is released is referred to. By setting the trailing margin, it is possible to avoid the back stain on the printing paper due to the so-called trailing edge with a shorter length.

According to the present invention, an appropriate so-called trailing edge margin is set according to the number of prints, and a shorter length is used to avoid back stains on the printing paper due to so-called trailing edge. Can be.

[Brief description of the drawings]

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

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

FIG. 3 is a perspective view of a bearing cover and a peripheral portion thereof.

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

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

FIG. 6 is a diagram illustrating the state of various types of printing paper placed on a paper feeding table and the arrangement of sensors.

7A is a perspective view illustrating a configuration of a mesh screen, FIG. 7B is a partial perspective view of a front stay, FIG.
(C) is a partial perspective view of the rear stay.

FIG. 8 is a partial cross-sectional front view of the mesh screen.

FIG. 9A is an exploded perspective view illustrating a manner of attaching a mesh screen to a printing drum, and FIG.
FIG. 9B is a partial perspective view illustrating the manner of attaching the mesh screen to the printing drum by the front stay, and FIG.
FIG. 3C is a partial perspective view illustrating the manner in which the mesh screen is attached to the printing drum by the rear stay.

10A is a development view of a printing drum around which a large-size master is wound, FIG. 10B is a development view of a printing drum around which a small-size master is wound, and FIG. )
FIG. 4 is a partial development view of a rear end portion of a small-sized master wound around a printing drum.

FIG. 11 is a perspective view of the print drum showing a state in which ink has leaked to the peripheral surface of the print drum outside the rear end of the master.

[Explanation of symbols]

 2 Large-size master (thermosensitive stencil) 2 'Small-size master (thermosensitive stencil) 84 Control means P3, P3' Back end of base paper P2, P2 'Press release position F, F' Rear margin

Claims (8)

[Claims] 1. A stencil making section for making a stencil sheet in roll form, a cutting section for cutting the stencil sheet, a stencil feeding section for conveying the stencil sheet, and an outer periphery of the stencil sheet. A printing drum for supplying ink by wrapping around a surface, a printing paper storage unit capable of storing printing paper of different sizes, and supplying the printing paper stored in the printing paper storage unit to the printing drum unit. The roller-type rotating body is pressed by the printing pressure unit to the outer peripheral surface of the printing drum in a range covering the plate making area via the paper feeding unit to be fed and the printing paper sent by the paper feeding unit, and then the pressing is released. Pressing means, control means for setting at least the timing of cutting the heat-sensitive stencil sheet in the cutting section, and switching means for switching the pressing length of the printing paper by the pressing means in the printing pressure section. It has to cut the thermosensitive stencil sheet according to the size of the printing paper and to set the pressing length of the printing paper, the printing drum passes the ink inside through a fine opening A screen region capable of oozing outward, and a weir element that does not ooze ink, and a rear end side of the heat-sensitive stencil wound around the printing drum, from a rear end position of the stencil making region to a position where the pressing is released. In the case of a large-sized heat-sensitive stencil sheet in which the weir element is located between the stencil element and the weir element is located at a position deviated from the area between the rear end position of the stencil making area and the pressure release position. In such a stencil printing apparatus, which may be a small-sized heat-sensitive stencil sheet, the distance from the press release position to the rear end of the base sheet for the small-size heat-sensitive stencil sheet is set to the large value. Stencil printing machine is characterized in that longer than in size stencil sheet of. 2. A stencil making section for making a stencil sheet in roll form, a cutting section for cutting the stencil sheet, a stencil feeding section for transporting the stencil sheet, and an outer periphery of the stencil sheet. A printing drum for supplying ink by wrapping around a surface, a printing paper storage unit capable of storing printing paper of different sizes, and supplying the printing paper stored in the printing paper storage unit to the printing drum unit. The roller-type rotating body is pressed by the printing pressure unit to the outer peripheral surface of the printing drum in a range covering the plate making area via the paper feeding unit to be fed and the printing paper sent by the paper feeding unit, and then the pressing is released. Pressing means, control means for setting at least the timing of cutting the heat-sensitive stencil sheet in the cutting section, and switching means for switching the pressing length of the printing paper by the pressing means in the printing pressure section. It has to cut the thermosensitive stencil sheet according to the size of the printing paper and to set the pressing length of the printing paper, the printing drum passes the ink inside through a fine opening A screen region capable of oozing outward, and a weir element that does not ooze ink, and a rear end side of the heat-sensitive stencil wound around the printing drum, from a rear end position of the stencil making region to a position where the pressing is released. In the case of a large-sized heat-sensitive stencil sheet in which the weir element is located between the stencil element and the weir element is located at a position deviated from the area between the rear end position of the stencil making area and the pressure release position. In such a stencil printing apparatus, which may be a small-sized heat-sensitive stencil sheet, the distance from the position where the pressure is released to the rear end of the base sheet is 60 for the small-sized heat-sensitive stencil sheet. m~100mm
A stencil printing apparatus characterized in that the size is as follows. 3. A stencil making section for making a stencil sheet in roll form, a cutting section for cutting said stencil sheet, a stencil feeding section for conveying said stencil sheet, and an outer periphery of said stencil sheet. A printing drum for supplying ink by wrapping around a surface, a printing paper storage unit capable of storing printing paper of different sizes, and supplying the printing paper stored in the printing paper storage unit to the printing drum unit. The roller-type rotating body is pressed by the printing pressure unit to the outer peripheral surface of the printing drum in a range covering the plate making area via the paper feeding unit to be fed and the printing paper sent by the paper feeding unit, and then the pressing is released. Pressing means, control means for setting at least the timing of cutting the heat-sensitive stencil sheet in the cutting section, and switching means for switching the pressing length of the printing paper by the pressing means in the printing pressure section. It has to cut the thermosensitive stencil sheet according to the size of the printing paper and to set the pressing length of the printing paper, the printing drum passes the ink inside through a fine opening A screen region capable of oozing outward, and a weir element that does not ooze ink, and a rear end side of the heat-sensitive stencil wound around the printing drum, from a rear end position of the stencil making region to a position where the pressing is released. In the case of a large-sized heat-sensitive stencil sheet in which the weir element is located between the stencil element and the weir element is located at a position deviated from the area between the rear end position of the stencil making area and the pressure release position. In such a stencil printing apparatus, which may be a small-sized heat-sensitive stencil sheet, the number of printed sheets is 250
A stencil printing apparatus characterized in that the distance from the pressure release position to the rear end of the stencil is 30 mm to 40 mm when the thermosensitive stencil sheet is replaced when the number of sheets is equal to or less than 250 or the number of printed sheets is 250. . 4. A stencil making section for making a stencil sheet in roll form, a cutting section for cutting the stencil sheet, a stencil feeding section for conveying the stencil sheet, and an outer periphery of the stencil sheet. A printing drum for supplying ink by wrapping around a surface, a printing paper storage unit capable of storing printing paper of different sizes, and supplying the printing paper stored in the printing paper storage unit to the printing drum unit. The roller-type rotating body is pressed by the printing pressure unit to the outer peripheral surface of the printing drum in a range covering the plate making area via the paper feeding unit to be fed and the printing paper sent by the paper feeding unit, and then the pressing is released. Pressing means, control means for setting at least the timing of cutting the heat-sensitive stencil sheet in the cutting section, and switching means for switching the pressing length of the printing paper by the pressing means in the printing pressure section. It has to cut the thermosensitive stencil sheet according to the size of the printing paper and to set the pressing length of the printing paper, the printing drum passes the ink inside through a fine opening A screen region capable of oozing outward, and a weir element that does not ooze ink, and a rear end side of the heat-sensitive stencil wound around the printing drum, from a rear end position of the stencil making region to a position where the pressing is released. In the case of a large-sized heat-sensitive stencil sheet in which the weir element is located between the stencil element and the weir element is located at a position deviated from the area between the rear end position of the stencil making area and the pressure release position. In a stencil printing apparatus which may be a small-sized heat-sensitive stencil sheet, the control means may include at least information on the number of printed sheets in addition to the size of the printing paper. Stencil printing apparatus characterized by setting the cutting timing of the thermal stencil sheet. 5. The stencil printing machine according to claim 4, wherein when the heat-sensitive stencil sheet of the small size is 1000 sheets or more, the distance from the release position to the rear end of the stencil sheet is 60 mm to 100 mm. When the heat-sensitive stencil sheet is a small-sized heat-sensitive stencil sheet and the number of printed sheets is 250 or less, or when the heat-sensitive stencil sheet is replaced every 250 print sheets, the distance from the pressure release position to the rear end of the base sheet is 30 mm to 4 mm.
The cutting timing to obtain a base paper size of 0 mm; and in the case of the large-size heat-sensitive stencil base paper, the cutting timing to obtain a base paper size in which the distance from the press release position to the rear end of the base paper is 15 mm to 20 mm. A stencil printing machine characterized by the following. 6. A stencil making section for making a roll of heat-sensitive stencil paper, a cutting section for cutting said heat-sensitive stencil paper, a stencil feeding section for transporting said heat-sensitive stencil paper, and an outer periphery of said heat-sensitive stencil paper. A printing drum for supplying ink by wrapping around a surface, a printing paper storage unit capable of storing printing paper of different sizes, and supplying the printing paper stored in the printing paper storage unit to the printing drum unit. The roller-type rotating body is pressed by the printing pressure unit to the outer peripheral surface of the printing drum in a range covering the plate making area via the paper feeding unit to be fed and the printing paper sent by the paper feeding unit, and then the pressing is released. Pressing means, control means for setting at least the timing of cutting the heat-sensitive stencil sheet in the cutting section, and switching means for switching the pressing length of the printing paper by the pressing means in the printing pressure section. It has to cut the thermosensitive stencil sheet according to the size of the printing paper and to set the pressing length of the printing paper, the printing drum passes the ink inside through a fine opening A screen area that can be oozed outward, and a weir element that does not ooze ink, and the rear end side of the heat-sensitive stencil wrapped around the printing drum, from the rear end position of the stencil making area to the pressure release position. In the case of a large-sized heat-sensitive stencil sheet in which the weir element is located between the stencil element and the weir element is located at a position deviated from the area between the rear end position of the stencil making area and the pressure release position. In a stencil printing apparatus that may be such a small-sized heat-sensitive stencil sheet, the distance from the pressing release position of the small-size heat-sensitive stencil sheet to the rear end of the stencil sheet may be the large stencil sheet. The distance from the pressing release position normally set for the heat-sensitive stencil sheet of the size to the rear end of the heat-sensitive stencil sheet is set to a predetermined value capable of covering the trailing area of the ink generated when the small-size heat-sensitive stencil sheet is applied to the small-size heat-sensitive stencil sheet. A stencil printing apparatus characterized by the above-mentioned. 7. A stencil printing apparatus according to claim 6, wherein said predetermined value is set to 2 of a distance from said pressing release position normally set for said large-sized heat-sensitive stencil sheet to a trailing edge of said sheet.
A stencil printing machine characterized by at least twice as large. 8. The stencil printing apparatus according to claim 6, wherein a distance from the pressing release position normally set for the large-size heat-sensitive stencil sheet to a rear end of the stencil sheet is 15 mm to 20 mm.
mm, the predetermined value is 60 mm to 100 mm when the number of printed sheets is 1000 or more, and 30 mm to 40 mm when the heat sensitive stencil sheet is replaced when the number of printed sheets is 250 sheets or less or every 250 printed sheets. Stencil printing machine.