JP2002137519A - Stencil printing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide printing equipment, which has a simple structure and from which a paper can be delivered with neither damaging the surface of an impression cylinder and the surface of an image nor developing the jamming of the paper. SOLUTION: At a position, which locates nearly a middle part in the axis line direction of a printing impression cylinder 8 and just after a downstream side from a printing pressure nip part B to the rotating direction of the printing impression cylinder 8, when a printing paper is thin, the thin paper is carried under the state being held down with a disc body 14, which is rotatably supported at a state approaching to the surface of the printing impression cylinder and the outer peripheral part of which has an uneven shape. When a printing paper is thick, the disc body is evacuated to a position, which does not interfere with the thick paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing drum (hereinafter, referred to as a master) carrying a printing drum which is opposed to a printing drum carrying a printing plate (hereinafter referred to as a master). The present invention relates to a stencil printing apparatus for performing printing on paper and a printing method.

[0002]

2. Description of the Related Art In a stencil printing machine, a perforated stencil sheet (master) is wound around the outer periphery of a printing drum composed of a plate cylinder or the like having a porous opening, and the printing drum is rotated. While the paper is pressed against the outer peripheral surface of the printing drum by the printing pressure means, ink is supplied in a layer to one surface of the master, a pressing force is applied to this ink layer, and the ink is applied to the other side of the master through the perforated portion of the master. This is a printing apparatus which realizes a printing method in which ink transferred through a master perforated portion is transferred to a surface to be printed and adhered to a printing surface pressed against the other surface of the master, and is already well known.

Conventionally, in this type of stencil printing apparatus, there has been a problem referred to as "paper ejection curling jam". In this "paper ejection curling jam", the paper pressed against the outer periphery of the print drum is stuck to the outer peripheral surface of the print drum due to the adhesive force of the ink, and cannot be peeled from the outer peripheral surface of the print drum. Trouble
The paper is thin and stiff, the printed image has many solid images,
It is likely to occur when the transfer amount of ink becomes large at high temperature and low speed.

As a method of preventing the "paper discharge curling jam" and peeling the paper from the outer periphery of the printing drum, roughly three methods have been proposed and commercialized.

[1]. As shown in FIG. 10, a paper discharge peeling claw 61 having a sharp tip is provided close to the outer circumference of the printing drum 50, and further, “air claw” that discharges strong air from the front end of the paper discharge peeling claw 61. Method ". This is disclosed, for example, in Japanese Utility Model Publication No. 4-15509.

In this technique, air is discharged only at the leading end of an image.
When the image is rubbed on the paper discharge peeling nail 61, or when the image area becomes large, the adhesion to the print drum 50 becomes strong and the winding is promoted, and the nail is stabbed at the portion where the paper discharge peeling nail 61 is in contact. May occur.

As a countermeasure, it is conceivable to constantly discharge air. In that case, however, a large air compressor is required so that the pressure does not change much, which increases the cost of the machine. In addition, there is a possibility that air flows into a paper feed unit or the like, and the leading end of the paper does not enter the paper clamper 52 properly, causing a problem such as a jam.

[2]. As shown in FIG. 10, a printing cylinder 50 having substantially the same diameter as the printing drum 50 is used as a printing pressure means by a technique referred to as “paper tip clamping impression cylinder method”. A concave portion 51a is provided in a part of the outer peripheral surface of the impression cylinder 51, and a paper clamper 52 is disposed in the concave portion 51a, and the paper clamper 52 is provided between the nail contact member 51a1 provided in the concave portion 51a and the paper clamper 52. Hold the tip. If a certain area where the printing drum 50 and the impression cylinder 51 are pressed against each other is defined as a printing pressure nip portion B,
An image is formed on the paper 53 at the printing pressure nip B while the paper 53 is sandwiched by the paper clamper 52, and the rotational position A of the impression cylinder 51 on the downstream side of the printing pressure nip B in the rotation direction of the impression cylinder 51. To open the paper clamper 52 to convey and discharge the paper 53 toward the paper discharge unit. The technique of this method is disclosed in Japanese Patent Application Laid-Open No. 8-183166.

In this technique, as shown in FIG. 10, the leading end of the paper 53 is conveyed while being clamped by the paper clamper 52, so that the leading end of the paper can be reliably separated from the printing drum 50. . However, in order to transfer the sheet 53 to the suction / discharge / conveyance device 54, the sheet clamper 52 must be opened at the rotation position A of the impression cylinder. At this time, if a solid image is printed in the print nip portion B, the ink Paper 53 by adhesive force
May be lifted as shown by the broken line in FIG. 10, and may not be properly sent to the suction / discharge / conveyance device 54, and may cause a paper ejection curling jam. Further, at the rotation position A of the impression cylinder, the leading end of the sheet may be caught on the scraper 55, which may cause a scraper jam. For example, when a solid image exists as shown in FIG. 11, it is considered that this trouble is particularly likely to occur.

In order to prevent the paper 53 from winding up at the printing pressure nip portion B shown in FIG. 10, there is a technique disclosed in Japanese Patent No. 2547366. However, in this technique, as shown in FIG.
3 at both ends, a paper ejection press roller 57a whose outer periphery is made of rubber.
By 57b, it is intended to press firmly against the outer surface of the impression cylinder 51 to prevent winding up,
The following problems may occur.

A discharge holding roller 57a is provided on the image side of the printed matter.
That is, the trace of the roller of 57b is clearly attached.
The ink on the image surface adheres to the outer circumferences of the paper discharge press rollers 57a and 57b, which in turn transfer to the surface of the paper 53 and become streak-like stains as indicated by reference numeral C.

[0012] The paper ejection pressing rollers 57a are arranged so as to be properly positioned at both ends of the paper according to the paper size.
Positioning 57b is cumbersome. Automatically and automatically detects the paper size and automatically discharges the rollers 57a, 57
Although there is a method of positioning b, the mechanism becomes complicated and the cost increases.

Although there is no problem when the surface of the impression cylinder 51 is a rigid body, an elastic body is generally used to ensure uniformity of the image and to reduce stress on the master. When the outer surface of the impression cylinder 51 is an elastic body, if the paper ejection pressing rollers 57a and 57b are strongly pressed, the paper 53 will have a fold mark, and the dent mark will also be formed on the outer surface of the impression cylinder.

[3]. This is a technique known as "unknown roller" in which a disc body is provided on the ejection claw in an uneven shape to approach the surface of the impression cylinder. As shown in FIG. Is rotated together with the impression cylinder 51 while the paper clamper 11 is clamped, and the paper clamper 11 is changed from "closed" to "open" in a portion A by a clamper opening / closing mechanism (not shown).
At this time, the printed paper 12 is located between the outer surface of the impression cylinder 51 and the guide roller 64 for preventing the ejection of the paper, and is conveyed by the impression cylinder 51 which is lightly sandwiched therebetween and rotates. Is applied, the printed paper 12 is prevented from sticking to the outer periphery of the plate cylinder 50, and the occurrence of paper ejection curling jam is prevented.

According to the technique relating to the guide roller system for preventing the paper ejection from being lifted, the above-described paper ejection roller system eliminates line stains, has no dent mark even with an impression cylinder having an elastic outer surface, and prevents winding-up jam at low cost. be able to.

As described above, in FIG. 13, the guide roller 64 for preventing the sheet from being lifted up has an uneven surface and a thickness of 0.1.
It is made of a sheet metal of about 0.3 mm, and has a clearance of 0.5 to 3 mm from the surface of the impression cylinder and the outer periphery of the guide roller 64 for preventing the ejection of paper. The sheet 53 is lightly sandwiched between both the guide port 64 for preventing the ejection of the sheet and the impression cylinder 51, and the conveying force is applied to the sheet 53 by the rotating impression cylinder 51. The purpose is to prevent a roll-up jam that sticks to the outer peripheral surface.

However, the following problems are also a concern in this technique. That is, as shown in FIG. 13, the guide roller 64 for preventing the ejection of the paper from being discharged is located below the printing pressure nip position B between the printing drum 50 and the impression cylinder 51. Guide roller 64
, There is a danger that even solid images may have nail marks. In the case of thin paper, there is no stiffness of the paper, so that there is a gap between the guide roller 64 for preventing the ejection of the paper and the impression cylinder 51, and thus, in the case of an image that is not solid, the above-mentioned claw mark does not occur.

When the thick paper jams at the portion of the guide roller 64 for preventing double-feeding or ejection, the paper 12 collides with the ejection roller 64 and the ejection roller 64 is pressed. Even if the surface of the impression cylinder dents and presses due to collision with
There is a possibility that the image will not appear on the dent scratched portion 4 and, if the thick paper is jammed by the double feed or the guide roller 64 for preventing the discharge rising, the guide roller 64 for preventing the discharge discharge rising may be damaged.

[0019]

SUMMARY OF THE INVENTION The present invention is directed to a stencil printing apparatus of the paper tip clamp impression cylinder type which solves the above-mentioned problems in the prior art and can prevent the occurrence of paper curling jam regardless of thin paper or thick paper. It is an object of the present invention to provide an inexpensive stencil printing apparatus.

[0020]

The present invention has the following configuration to achieve the above object. (1). A porous cylindrical printing drum, which is formed by winding a perforated plate-making master around an outer peripheral surface and rotating; and a printing pressure as a pressing means which is provided so as to be able to contact and separate from the printing drum and has substantially the same diameter as the printing drum. A cylinder, and the printing cylinder has a clamper for holding the leading end of the paper supplied from the paper feeding unit to the printing cylinder, and presses the printing cylinder against the printing drum via the paper. In a stencil printing apparatus that performs printing by moving ink from the master perforated portion to the paper from within the printing drum, the stencil printing machine is disposed at a substantially central portion in the axial direction of the impression cylinder, and rotates in the rotation direction of the impression cylinder. An outer periphery which is movably held at a first position very close to the surface of the printing cylinder at a position immediately after the printing pressure nip portion and at a second position which does not interfere with the rotation locus of the master clamper of the printing drum; Disc body with irregularities It was to have (claim 1). (2). (1) The stencil printing machine according to (1), further comprising a disk body having an outer peripheral portion formed with irregularities, rotatably held at a third position very close to a rotation locus of the clamper immediately after the printing pressure nip portion. (Claim 2). (3). (2) The stencil printing machine according to (2), wherein the third
The disk body having an irregular outer peripheral portion rotatably held at the position (1) is provided in a part of the duct of the air knife fan (Claim 3). (4). (1) The stencil printing machine according to (1), further comprising a switching unit that automatically switches between the first position and the third position by inputting a sheet thickness, and a control unit that controls the switching unit. Item 4). (5). (1) In the stencil printing apparatus described in (1), a sheet detecting means for detecting the thickness of the sheet is provided, and the first position and the third position are automatically switched according to the sheet thickness. ). (6). (1) In the stencil printing apparatus according to any one of (1) to (5), the outer peripheral portion of the disk body having irregularities has an outer diameter dimension of 15 mm or less, and the first position is located at the center of the printing drum. An angle formed by a line segment passing through the center of the disk body with respect to a line connecting the axis of the printing cylinder with the center of the axis of the printing cylinder on the downstream side of the printing pressure nip portion ( θ) is within 30 degrees, and the third position of the printing pressure nip portion is centered on the axis of the printing drum with respect to a line connecting the axis of the printing drum 1 and the axis of the printing cylinder. An angle opened to the downstream side, an angle (β) formed by a line segment passing through the center of the disk body being within 45 degrees, and a lower portion of the disk body provided at a position higher than the printing pressure nip portion ( Claim 6). (7). As a porous cylindrical printing drum which is wound around a perforated plate (master) around its outer peripheral surface and is rotatable with respect to the printing drum, a pressing means having substantially the same diameter as the printing drum is provided. The printing pressure cylinder has a clamper for holding the leading end of the paper supplied from the paper feeding means to the printing pressure cylinder, and the printing pressure is applied to the printing drum via the paper. In a stencil printing apparatus for performing printing by pressing the cylinder and moving ink from the master perforated portion to the paper from within the printing drum, the outer peripheral portion has a disc body having irregularities, and the disc body has an outer diameter dimension. 15 mm or less, an angle opened to the downstream side of the printing pressure nip portion with respect to a line connecting the axis of the printing drum and the axis of the printing pressure cylinder with respect to the axis of the printing pressure cylinder, The angle (θ) formed by the line segment passing through the center of the disk is within 30 degrees, The top of the serial disk body is provided at a position lower than the printing pressure nip portion (claim 7). (8). (1) In the stencil printing apparatus according to any one of (1) to (7), a pair of discs having an outer peripheral portion with irregularities are provided, and the distance between the pair is determined by central distribution in the axial direction of the impression cylinder. It was 20 to 150 mm (claim 8). (9). In the stencil printing apparatus according to any one of (1) to (8), an auxiliary roller made of an elastic body is brought into contact with the disk body having an uneven outer peripheral portion (claim 9). (10). In the stencil printing machine according to any one of (1) to (9), an elastic auxiliary roller is brought into contact with the disk having an outer peripheral portion having irregularities, and a foam is used for the auxiliary roller. (Claim 10). (11). (1) In the stencil printing apparatus according to any one of (1) to (10), an auxiliary roller made of an elastic material is brought into contact with the disk body having an outer peripheral portion having irregularities, and the outer diameter of the auxiliary roller is set to the disk. The diameter is set to 1 to 3 times the outer diameter of the body (claim 11). (12). (1) The stencil printing machine according to any one of (1) to (11), further comprising adjusting means for adjusting a distance between the disk and the impression cylinder (Claim 12). A porous cylindrical printing drum, which is formed by winding a perforated plate-making master around an outer peripheral surface and rotating; and a printing pressure as a pressing means which is provided so as to be able to contact and separate from the printing drum and has substantially the same diameter as the printing drum. A cylinder, and the printing cylinder has a clamper for holding the leading end of the paper supplied from the paper feeding unit to the printing cylinder, and presses the printing cylinder against the printing drum via the paper. In a printing method in which ink is transferred from the master perforated portion to the paper from within the printing drum and printing is performed, when a predetermined thin paper is used as the printing paper, the printing pressure nip portion is disposed in the rotation direction of the printing pressure cylinder. The thin paper is conveyed while being pressed against the impression cylinder side by a disk body having an outer peripheral portion having irregularities at a position immediately after the above, and when using a predetermined thick paper as a printing paper, the disk body is in a non-interference state with the thick paper. Or the printing pressure nip It was decided to transport while supporting the cardboard from the bottom of the disk body at a position immediately after the section by positioning between the printing pressure cylinder and said cardboard (claim 13).

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Three embodiments will be described below. [First Embodiment] FIG. 1 illustrating a part of a stencil printing apparatus.
In the figure, reference numeral 1 denotes a printing drum capable of carrying a master for printing on a peripheral surface. A printing cylinder 8 is arranged to face the printing drum 1. The impression cylinder 8 has a paper clamper 11 having substantially the same diameter as the printing drum 1 and holding the leading end of the paper 12, and is driven to rotate in the opposite direction to the printing drum 1.

When the printing drum 1 rotates clockwise as indicated by an arrow 600, the impression cylinder 8 is driven to rotate counterclockwise as indicated by an arrow 610. The printing drum 1 has a porous and cylindrical plate cylinder 2, and a master clamper 4 is provided on the outer periphery of the plate cylinder 2. The master is wound around the plate cylinder 2 in a state where the master clamper 4 holds the leading end of the master 3 having been made.

Inside the printing drum 1, there are provided an ink roller 5 as an ink supply device, a doctor porter 6, an ink reservoir 7, and the like. The plate cylinder 2, the ink roller 5, and the doctor roller 6 are each driven to rotate in the direction of the arrow shown in FIG.

An elastic layer 9 made of a foam is provided on the outer peripheral surface of the impression cylinder 8, and the impression cylinder 8 is rotated by a mechanism (not shown) in the direction of arrow 610 in FIG. 2 and at a predetermined timing with a predetermined pressing force.

The impression cylinder 8 has a recess 10 formed in a part of the outer peripheral surface thereof in the axial direction. A claw contact member 10a made of resin is provided inside the concave portion 10 and on a slope portion on the upstream side in the rotation direction so as to cover the elastic layer 9.
The concave portion 10 is provided with the paper clamper 11 so that the leading end of the paper 12 can be sandwiched between the nail contact member 10a.
Is provided.

Sheets stacked on a sheet feeding table (not shown) are separated by a sheet feeding device (not shown) and conveyed toward a pair of registration rollers 13.
If the separated sheet is indicated by reference numeral 12, the sheet 12 is sent out by the registration roller 13 at a specific timing, and the printing pressure nip portion B, which is a press contact portion between the printing drum 1 and the printing pressure cylinder 8, is moved from the printing pressure cylinder. 8 which is the upstream position in the rotation direction
When the paper clamper 11 is changed from the “open” state to the “closed” state by a clamper opening / closing mechanism (not shown) in the section, the leading end portion is nipped, and the printing pressure
, Where printing is performed.

The paper 12 rotates together with the impression cylinder 8 with its leading end portion clamped by the paper clamper 11, and is closer to the outer periphery of the impression cylinder 8 than the impression nip B in the direction of arrow 610. It reaches part E which is a downstream position. An immovable scraper 15 is located in this E section. In addition, a sheet conveying device 16 including an endless belt-shaped suction type conveying unit is provided adjacent to the scraper 15. The transporting device 16 has a function of transporting the paper 12 to a discharge tray (not shown) outside the printing pressure cylinder 8 at the printing pressure nip portion B.

The position near the outer peripheral surface of the printing cylinder 8 and between the printing nip B and the scraper 15, or, in other words, the position immediately after the printing nip B in the rotational direction of the printing cylinder 8 At a first position very close to the surface of the printing cylinder, a guide roller 1 for preventing the ejection of paper from rising, which is formed as a disk body.
4 are located.

The paper clamper 11 is changed from "closed" to "open" by a clamper opening / closing mechanism (not shown) in the section E. At this time, the printed portion of the paper 12 includes the outer surface 9a of the impression cylinder 8 and the guide roller 14
, And is lightly sandwiched between the two, and is conveyed while being imparted with a conveying force by the rotating printing pressure cylinder 8. For this reason, the paper 12 does not stick to the outer periphery of the cylindrical plate cylinder 2, and
The occurrence of the paper ejection curling jam is prevented.

After the paper clamper 11 is in the "open" state at the portion E, if the paper 12 is thin paper or the printed image is a solid image, the paper 12 is wound around the outer circumference of the plate cylinder 2. When the ink sticks to the surface of the master 3 due to the adhesive force of the ink, a slight curling occurs as shown by a broken line in FIG. However, the amount of this winding does not become larger than a certain amount, and it does not cause a jam, and is guided by the scraper 15 to be transported by the transfer device 16.
You will be correctly guided up.

As shown in FIG. 2, the guide roller 14 for preventing the ejection of paper from rising comprises a disk 14a made of a metal having irregularities on its outer periphery, for example, jagged teeth, and a holder 14b made of a resin for holding the disk 14a. In other words, two are provided so as to face substantially the center of the printing cylinder 8 in the axial direction. The disk 14a is rotatably held around an axis 17. The shaft 17 has a holding arm 18 at its longitudinal center.
It is fixed to. The holding arm 18 is inserted through the support shaft 19 at the base end thereof, and is prevented from rotating with respect to the support shaft 19 by interposing a key (not shown). The holding arm 18 is substantially integrated with the support shaft 19. To rotate.
Therefore, the shaft 17 can hold the holding arm 18 at a fixed position, for example, the first position, with holding the fixed position.

As described above, the guide roller for preventing the paper ejection lifting is moved to the first position, that is, immediately after the printing pressure nip portion B in the rotation direction of the printing pressure cylinder 8 and on the surface of the printing pressure cylinder. Since the disk body having an uneven surface is rotatably held and arranged at a very close position, even when printing a solid image on thin paper, the paper 12 adheres to the printing drum 1 after the paper clamper 11 is opened. Even if the paper 12 is to be wound up by force, the sheet 12 will not be pulled back to the print drum 1 side because the paper ejection lifting prevention guide roller 14 is pressed from above. Therefore, it is possible to prevent the occurrence of a paper ejection curling jam regardless of a solid image or a character image.

Further, the holding arm 18 is swung to move the rotation locus 4 of the master clamper 4 of the printing drum 1 from the first position.
When switching to the second position which does not interfere with a, printing can be performed on thick paper without the trace of the roller formed by the disk body l. With a simple and inexpensive configuration, both thin paper and thick paper can be handled.

1 and 2, a pair of auxiliary rollers as auxiliary rollers for sucking ink from the guide roller 14 for preventing the lifting of the sheet so as to be in contact with the outer periphery of the guide roller 14 for preventing the rising of the sheet at the first position. Is rotatably mounted on a shaft 32. The shaft 32 is also fixed to the holding arm 18. From the results of the experiment, it was found that if the diameter of the ink suction roller 31 is set to be 1 to 3 times the outer diameter of the guide roller 14 for preventing the rising of the discharged paper, the ink absorption is good.

Since the outer diameter of the pair of ink suction ports 31 as auxiliary rollers is set to be one to three times the diameter of the outer peripheral portion of the guide roller 14 for preventing the rising of the paper discharge as a disk, the ink suction ports 31 are provided. The ink absorbing area of the sheet is large, the state in which no ink adheres to the guide roller 14 for preventing the discharge of paper from floating can be maintained for a long time, and the stain on the image surface of the sheet can be prevented for a long time.

An elastic body is used as the ink suction roller 31. Specifically, urethane foams, especially microcells such as PORON [trade name of INOAC CORPORATION] and silicone rubber, nitrile rubber, urethane rubber, and other elastic materials are good for absorbing ink.

As described above, by contacting the ink suction roller 31 made of an elastic material with the outer periphery of the paper ejection prevention guide roller 14 having an uneven outer peripheral portion, the ink attached to the outer periphery of the paper ejection prevention guide roller 14 is removed. Absorb,
It can be wiped off, and thereby, it is possible to prevent roller trace contamination on the image surface of the sheet 12 via the guide roller 14 for preventing the sheet from being lifted up.

The ink sucking roller 31 is made of an elastic material, and the ink sucking roller 31 made of the elastic material is brought into contact with the guide roller 14 for preventing the rising of the discharged paper. The guide roller 14 can be removed by suction from the guide roller 14 for preventing the sheet from being lifted, and the roller track stains that further transfer to the image surface of the sheet from the sheet roller for preventing the sheet from being lifted 14 can be prevented.

Further, since the ink suction roller 31 is made of an elastic material and made of a foam, the ink can be sucked into the air portion of the foam, and the guide roller 14 for preventing the floating of the discharged paper does not adhere. Can be maintained for a long time, and the dirt and stains on the image surface of the paper can be prevented for a long time.

As described above, it is possible to prevent the paper from winding up when the paper is thin. Next, the case of thick paper will be described. When the paper is a thick paper, the stiffness of the paper is larger than that of the thin paper. If the sheet is left as it is, it is inevitably conveyed by being pressed against the guide roller 14 for preventing the rising of the discharged sheet, so that there is a problem that a roller mark is easily generated on thick paper compared to thin paper. Further, when the paper is thick paper, the impact at the time of jamming is large, and there is a concern that the guide roller 14 for preventing the raised paper ejection from sticking to the outer surface of the printing pressure cylinder 8.

In order to solve the above problem, a support shaft 19 is provided in parallel with the axial direction, and the base end of the holding arm 18 is pivotally connected to the support shaft 19. Thereby, the holding arm 1
Numeral 8 is rotatable about the support shaft 19 while holding the guide rollers for preventing the ejection of paper and the ink suction roller 31.

When thick paper is used as the paper, the holding arm 18 interferes with the printing drum 1 when passing the guide roller 14 for preventing the rising of the discharged paper. Therefore, in order to avoid this interference, the printing drum 1 is pulled out in advance in the axial direction. Then, the guide roller 14 for preventing the ejection of the paper is lifted, and the holding arm 18 is manually moved by the operator around the support shaft 19 as shown in FIG.
Is rotated counterclockwise. Thus, the holding arm 18 and the guide roller 1 for preventing the sheet from being lifted up
4. The second showing the ink suction roller 31 and the like with a two-dot chain line
Can be moved to the position. Thereafter, the printing drum 1 is mounted again on the stencil printing apparatus main body.

In both the second position and the first position,
Printing pressure nip B in the rotation direction of printing drum 1 and printing cylinder 8
And the guide roller 14 for preventing the ejection of the paper does not interfere with the master clamper 4 provided on the printing drum 1 nor with the rotation locus of the paper clamper 11.

The guide roller 14 for preventing the sheet from being lifted up
The means for holding the first position and the second position will be described later with reference to FIG. In FIG. 2, the duct 102 is provided so as not to be obstructed when the paper ejection lifting prevention guide roller 14 is retracted to the second position shown by a two-dot chain line in FIG.
Are provided.

When thick paper is used as the paper, the guide roller 14 for preventing the rising of the discharged paper is moved to the second position in advance. Accordingly, since the sheet is not at the first position, the thick sheet in FIG.
However, on the downstream side of the printing pressure nip portion B, the sheet is located at a spatial position raised from the outer surface 9a by the waist of the sheet, as indicated by reference numeral 12 '.

That is, the sheet 12 'passes through a space position slightly below a horizontal line KK (actually a horizontal plane, the same applies hereinafter) passing through the printing pressure nip portion B. The paper ejection lifting prevention guide roller 14 is retracted to a second position indicated by a two-dot chain line above the paper 12 '. For this reason, there is no occurrence of a roller trace that is likely to occur when the guide roller 14 for preventing the ejection rising of the sheet comes into contact with the sheet, and there is no guide roller 14 for preventing the ejection of the sheet even during a jam.
Guide roller 1 for preventing paper ejection from rising on surface 9a of printing cylinder 8
4 can be conveyed without being stuck.

Reference numeral 12 'indicates that the paper is thick paper.
Since the paper itself has a stiffness as shown by, even in the case of a locally solid image having a large amount of ink, it is located below the horizontal line KK, and a so-called curling phenomenon in which a locally upwardly convex shape is exhibited. Does not occur. Therefore, in principle, a thick paper lifting prevention roller 103 described later is not required. Also, in the case where the entire surface of the paper is an image close to solid, or when the amount of ink transfer becomes large at a high temperature and a low speed, the thick paper is lifted considerably above the horizontal line KK. In order to prevent such lifting, a duct 102 is provided integrally with the air knife fan 101 so as to guide air toward the printing pressure nip portion B.

From the outlet of the air from the duct 102 (indicated by reference numeral 102b in FIG. 2), as shown by the arrow Q in FIG.
The air is blown toward the position immediately after the downstream side, that is, the position of the drum 1 at 7 to 8 o'clock when expressed on a clock face. This air travels along the peripheral surface of the plate cylinder 2 toward the printing pressure nip portion B, and removes the thick paper 12 ′ from the outer surface 9 a of the printing cylinder 8.
Acts to press. As a result, even when thick paper on which an image almost solid on the entire surface is printed, an abnormal upward lifting such as contact with the printing drum 1 is avoided.

By utilizing the tip of the duct 102 on the side of the air outlet, a guide roller 103 for preventing the floating of the thick paper having the same shape as the guide roller 14 for preventing the floating of the sheet as a disk is provided. In other words, as shown in FIG. 2, the guide roller 103 for preventing the rising of the thick paper is provided with a disk 103a made of metal having irregularities on its outer periphery, for example, a metal having jagged teeth, and a holder 103 made of a resin for holding the disk 103a.
b, and is rotatable while being supported by the shaft 104;
A pair facing the substantially central portion in the axial direction of the impression cylinder 8 is provided.
That is, two are provided.

The appropriate position of the guide roller 103 for preventing the rise of the thick paper is determined by the guide roller 1 for preventing the thick paper from rising.
03 is a space position above the horizontal line KK and downstream of the printing nip B in the rotational direction of the printing drum 1, the printing cylinder 8 and the like, and the separation angle β is 45 degrees. , And this position was set as a third position. Here, the separation angle β is the axis O1 of the printing drum 1 in FIG.
With respect to a line connecting the axis O8 of the printing pressure cylinder 8 and the downstream side of the printing pressure nip portion B about the axis O1,
This is an angle formed by a line segment passing through the center of the thick paper lifting prevention guide roller 103.

By satisfying this condition, even when thick paper is used as the paper, the guide roller 1 for preventing the floating of the thick paper is used.
It has been confirmed by experiments that the contact pressure on the cardboard is low due to No.03, so that the roll-up of the cardboard can be prevented while the stain on the roller is reduced. Even when a jam or double feed occurs, the gap between the outer surface 9a and the thick paper lifting prevention guide roller 103 is wide, so that the jammed paper or the double feed paper pushes down the thick paper lifting prevention guide roller 103 and pushes the printing roller 8 down. Collision and damage to the impression cylinder 8 are avoided.

At a position where the separation angle β exceeds 45 degrees, the guide roller 103 for preventing the lifting of the thick paper does not function. Even if the separation angle β is less than 45 degrees, the thick paper lifting prevention guide roller 103 must not interfere with the rotation locus 4a of the master clamper 4, and the lower part of the outer diameter of the thick paper lifting prevention guide roller 103 has a horizontal line KK. Satisfying the condition of being above is sufficient to prevent the lifting of the cardboard.

By providing the guide roller 103 for preventing the rising of the thick paper at the third position, the lifting of the thick paper to be lifted can be efficiently suppressed beforehand. Further, even when the heavy paper is fed or the paper is jammed by the guide roller 103 for preventing the rising of the discharged paper, the gap between the guide roller 103 for preventing the rising of the thick paper and the impression cylinder 8 is large, so that the jammed paper or the like is prevented from rising. When the guide roller 103 rides on the guide roller 103 and collides with the printing cylinder 8 to prevent the thick paper lifting, the surface of the printing cylinder 8 is depressed.

A mechanism for holding the holding arm 18 shown in FIG. 1 so that the paper ejection lifting prevention guide roller 14 can take the first position and the second position will be described. In FIG. 3 in which the configuration around the holding arm 18 in FIG. 1 is enlarged and shown, the interval F between the tooth tip of the serrated teeth of the lift prevention guide roller 14 and the outer surface 9a of the printing pressure cylinder 8 is determined by the printing pressure cylinder 8. 0 to 0 when pressed toward the printing drum 1
It is set to be 3 mm.

Here, the guide roller 1 for preventing the ejection of paper from being lifted up
4 can be revolved around the support shaft 19 together with the auxiliary arm 18 so as to be retracted to a position where the passage of the sheet is not hindered, and the distance F between the guide roller 14 and the impression cylinder 8 can be adjusted. The following configuration is used to make it possible.

2 and 3, the support shaft 19 is rotatably supported by the side plates 501 and 502 of the stencil printing machine. A fan-shaped sheet metal cam 20 is fixed to one end of the support shaft 19. I have. Semicircular grooves 20a and 20b into which roller-shaped cam followers 21 can be fitted are formed near both ends of the arc-shaped portion of the sheet metal cam 20, respectively.

The cam follower 21 is rotatably supported by a shaft 22 fixed to an elongated plate-like adjustment link 23. In the state shown in FIG. 3, the cam follower 21 is
a. The adjustment link 23 is located at the left end 23b.
Are pivotally attached to a shaft 25 provided on the adjustment arm 27. The right end 23a1 of the adjustment link 23 is hung on one end side of a contractible spring 24 for pressing the cam follower 21 against the cam 20. The other end of the spring 24 is hung on a stationary member.

The adjustment arm 27 is a triangular plate-shaped member, and the upper part thereof is pivotally connected to the fulcrum shaft 26. The fulcrum shaft 26 is fixed to the side plate 502. Adjusting arm 2
An arc-shaped long hole 27a centering on the fulcrum shaft 26 is formed at the lower end of the screw 7, and the adjusting screw 28 is screwed into the side plate 502 through the long hole 27a. Adjustment screw 2
8, the adjustment arm 27 is moved to the side plate 50.
2 and cannot rotate around the fulcrum shaft 26 due to the frictional force, and the position is fixed.

In order to adjust the interval F between the guide roller 14 and the printing cylinder 8, the adjusting screw 28 is loosened in advance, and the adjusting arm 27 is centered on the fulcrum shaft 26 in the direction of arrow L in FIG. It is rotated clockwise or counterclockwise about the fulcrum shaft 26. In response to this rotation, the adjustment link 23 connected to the adjustment arm 27 is perpendicular to the axis O8 of the impression cylinder 8 and in the horizontal thrust direction M,
Move right or left. Accordingly, the cam follower 21 engaged with the groove 20a also moves rightward or leftward, and this operation is transmitted to the cam 20, and the cam 20 rotates around the fulcrum shaft 19. For example, if the adjusting arm 27 is moved rightward, the cam 20 rotates in the counterclockwise direction N, and the interval F is widened.
If the adjustment arm 27 is moved to the left, the interval F can be reduced by the reverse operation. After adjusting the interval F,
The adjusted interval F is maintained by tightening the adjusting screw 28.

Here, an adjusting link 23, a spring 24, an adjusting arm 27 and an adjusting screw 28 provided as a mechanism for rotating the cam 20 and a cam follower 21 serving as a connecting means of the adjusting link 23 and the sheet metal cam 20 are provided. The groove 20 a and the like constitute adjusting means for adjusting the distance F between the outer surface 9 a of the printing pressure cylinder 8 by moving the guide roller 14 for preventing the sheet from being lifted.

Both ends of the arc-shaped portion of the cam 20 are formed with grooves 20a.
The stoppers 20d1 and 20d2 are formed to have a height higher than the arc-shaped portion between the groove 20b and the groove 20b. These stoppers 20d1 and 20d2 have a function of preventing the cam follower 21 from coming off the circular cam surface of the cam 20.

For example, when a jam occurs, even if the jammed paper rides on the holding arm 18 and tries to push down the holding arm 18, since the stopper 20d2 is effective, the rotation of the sheet metal cam 20 is prevented, and the paper is ejected. The paper lifting prevention guide roller 14 can be prevented from hitting the printing cylinder 8.

Also, in the event that jammed paper enters between the guide roller 14 for preventing the ejection of the paper and the outer surface 9a of the impression cylinder 8, the cam 20 may not rotate counterclockwise. Since the guide roller 14 is not restricted, the guide roller 14 for preventing the ejection of the paper from rising can escape upward, thereby preventing the guide roller 14 for preventing the ejection of the paper from rising and the outer surface 9a of the printing cylinder 8 from being damaged.

When retracting the guide roller 14 for preventing the sheet ejection from rising and positioning the guide roller 14 at the second position, the plate cylinder 2 is previously moved from the stencil printing apparatus so that the sheet roller 2 for preventing the sheet ejection from rising will not hit the cylinder 2. After the extraction, the following operation is performed. That is, in FIG.
Lift and rotate counterclockwise. Accordingly, the cam 20 fixed to the support shaft 19 also rotates in the counterclockwise direction N. Thereby, the cam follower 2
1 enters the groove 20b, and the guide roller 1
4 is held in the third position. During this operation, the stopper 20d1 functions as a stopper for preventing the cam follower 21 from overrunning from the cam surface.

As shown in FIG. 2, if the clearance H between the two guide rollers 14 for preventing the ejection of the paper is too large, they are too far from each other. As a result, the paper is easily rolled up, and the ability to prevent the paper from being rolled up is reduced, which is not preferable. On the other hand, if the interval dimension H is too small, the function of holding down the sheet within a certain range with the two sheet ejection prevention guide rollers 14 is not sufficient, which is not preferable.

As a result of the experiment, the dimension H was 20 to 150.
mm was found to be optimal. The optimum dimension of the interval H changes depending on the size G of the sheet to be passed, but it can be generally adjusted to 20 to 150 mm.
Needless to say, these two guide rollers 14 for preventing the ejection of the paper from being lifted up.
It is effective that they are arranged at positions equally distributed to the left and right with respect to the center of the sheet in the drum axis direction.

As described above, the interval between the pair of guide rollers 14 for preventing the rising of the discharged paper is set to an appropriate value. If the interval is too large, it is easy to stick to the print drum at the center in the axial direction of the print drum and wind up. The ability to prevent the paper ejection curl phenomenon does not decrease,
An appropriate roll-up preventing function can be achieved without losing the effect of stably pressing the paper because the respective guide rollers 14 for preventing the lift of the discharged paper are too close to each other.

In order to dispose the discharge lifting guide roller 14 as close to the printing pressure nip B as possible, it is necessary to reduce the outer diameter J of the discharge lifting guide roller 14. Specifically, diameter 15mm
By setting the following, the angle of separation about the axis O8 from the contact point where the paper ejection lifting prevention guide roller 14 contacts the outer surface 9a of the impression cylinder 8 to the impression nip B,
That is, it can be achieved by setting the separation angle θ in FIG. 1 within 30 degrees. More preferably, the outer diameter J is 10 mm.
The separation angle θ is set to 25 degrees or less.

The experimental results show that the smaller the separation angle, that is, θ in FIG. 1, the smaller the solid winding degree α (the winding amount indicated by the broken line in FIG. 1) after the paper clamper 11 is opened. .

As described above, by setting the outer diameter of the guide roller 14 for preventing the ejection of the sheet from rising to 15 mm or less, the guide roller 1 for preventing the ejection of the sheet from rising at the first position.
4 can be provided as close to the printing pressure nip portion B as possible, so that the angle of separation θ of the discharge roller floating prevention guide roller 14 from the printing pressure nip portion B on the printing pressure cylinder is 3 °.
0 degrees, and even when a solid image of thin paper is used, the solid winding degree α (the winding amount indicated by the broken line in FIG. 1) after the paper clamper 11 is opened can be reduced, so that the discharge paper winding prevention ability is high and the ink The amount of metastasis does not increase.

The guide roller 14 for preventing the rising of the discharged paper is composed of a disk 14a having a large number of knurled teeth made of a thin metal sheet, and the ink is transferred to the surface of the printed image by the guide roller 14 for preventing the rising of the discharged sheet. Dirt can be reduced. Specifically, the thickness is 0.1 to 0.1.
A 3 mm stainless plate is used. It is preferable to perform heat treatment from the viewpoint of improving durability. Since only this thin stainless steel plate has insufficient strength, holder members 14b made of synthetic resin or the like are provided on both sides thereof, and are sandwiched between them.

The shape of the guide roller 103 for preventing the rising of the thick paper will be described. As shown in FIG. 2, the spacing dimension P of the two thick paper lifting prevention guide rollers 103 is too large, they are too far apart, so that the paper sticks to the printing drum 1 at the center of the printing drum 1 in the axial direction. It is easy to wind up, and the discharge winding prevention ability is undesirably reduced.

On the other hand, if the interval P is too small, it is not preferable because the effect of holding the paper in a certain range by the two discharge lifting prevention guide rollers 14 cannot be sufficiently exhibited. As a result of the experiment, the interval dimension P is set to 20 to 20 in the same manner as the interval dimension H of the guide roller 14 for preventing the sheet from being lifted.
It turned out that about 150 mm is optimal.

Although the optimum dimension of P changes depending on the size G of the sheet to be passed, it can generally be handled by setting it to 20 to 150 mm. Of course, it is effective that the two thick paper lifting prevention guide rollers 14 are respectively disposed at positions equally distributed to the left and right with respect to the center of the paper in the printing drum 1 in the axial direction.

The outer diameter of the thick paper lifting prevention guide roller 103 is desirably 15 mm or less, which is the same as the outer diameter J, since it has the same shape as the discharged paper lifting prevention guide roller 14. The position is 45 degrees apart angle β as defined above.
Experiments have confirmed that the effect of reducing roller stains on thick paper can be reduced by setting the air knife fan and the duct 102 in a position where the separation angle β is within 45 degrees in this example. A guide roller 103 for preventing the rising of the thick paper is attached to a part of the duct 102.

The third position occupied by the cardboard lifting prevention guide roller 103 is the cardboard lifting prevention guide roller 103.
Is located above the horizontal line KK,
In addition, the lower part of the outer diameter of the guide roller 103 for preventing the rising of the thick paper is provided at a position lower than the bottom of the duct 102 so that the upper surface of the thick paper does not rub against the bottom surface of the duct 102 and rub against the image surface. From the results of the experiment, it was found that it was possible to prevent the lifting of thick paper. The guide roller 103 for preventing the rising of the thick paper is required to be arranged at a position where the separation angle β is within 45 degrees.

The guide roller 103 for preventing the rising of the thick paper is
The same roller as the guide roller 14 for preventing the rising of the discharged paper is used, and by using the disk 103a having a large number of concave and convex teeth having a sharp tip made of a thin metal sheet, the guiding roller for preventing the rising of the thick paper on the printed image surface is used. The transfer stain of the ink 103 can be reduced. Specifically, a stainless steel plate having a thickness of 0.1 to 0.3 mm is used.
It is preferable to perform heat treatment from the viewpoint of improving durability. Since the thin stainless plate alone is insufficient in strength, holder members 103b made of synthetic resin or the like are provided on both sides thereof and sandwiched between them.

The guide roller 103 for preventing the rising of the thick paper rotatably held at the third position is connected to the air knife fan 1.
Since it is provided using the duct 102 of No. 01, it is not necessary to increase the number of parts as compared with a case where a support member is newly provided, and a simple configuration can be realized.

In the first embodiment, the guide roller 14 for preventing the paper ejection from being lifted can be retracted,
By providing a guide roller 103 for preventing the rising of the thick paper in a part of the first duct 102, the ink transfer stain at the time of the thick paper is eliminated, and the guide roller 14 for preventing the rising of the discharged paper at the time of the jam is retracted to the third position. Outer surface 9a of impression cylinder 8
However, it is necessary to judge the difference between thick paper and thin paper at the user's discretion and manually switch the ejection floating prevention guide roller 14 between thick paper and thin paper. There is an inconvenience that the guide roller 14 for preventing the rising of the discharged paper must be reset to an appropriate position, and there is a possibility that a setting error such as setting of a thick paper at the time of thin paper may occur. The second embodiment described below solves this problem.

[Second Embodiment] In the second embodiment described below, the position of the guide roller 14 for preventing the lifting of the sheet discharged when thick paper and thin paper are automatically set to an appropriate position. It is a means that can be set without
This will be described with reference to FIGS.

In these figures, the printing method and the paper conveying method are the same as those in the first embodiment, and the same members as those in FIGS. 1 to 3 are shown in FIGS. , The same reference numerals are given, and the description will not be repeated unless it is particularly important.

FIG. 4 is a view of the printing drum 1 as viewed from its axial direction, and FIG. 5 corresponds to a plan view of FIG. 4 and 5
In FIG.
As shown in FIG. 3, a disk 14a made of a thin metal plate having uneven jagged teeth on the outer periphery and a resin holder 14b holding the disk 14a are provided.
7 rotatably held.

The shaft 17 is fixed integrally with the guide roller holding arm 110 by penetrating a bifurcated portion at one end of the guide roller holding arm 110 having a substantially rectangular parallelepiped shape. A rack 110a is integrally formed below the guide roller holding arm 110.
The pinion 119 meshes with 0a. Pinion 11
9 is fixed to the shaft 118. Both ends of the shaft 118 are supported by side plates (not shown).

A worm wheel 129 is fixed to one side of the shaft 118. The worm wheel 129 meshes with the worm 120. The worm 120 is fixed to a rotation shaft of the stepping motor 121. When the stepping motor 121 rotates, the worm 120 rotates in accordance with the rotation direction, and this rotation is transmitted to the pinion 119, and the guide roller holding arm 110 can reciprocate in the direction of the arrow 503.

The guide roller holding arm 110 has a rectangular parallelepiped shape as described above, and has an end face 110 in the sheet width direction.
b can be guided and slid by the arm holder 111 having a housing shape, is held by the arm holder 111, and the guide roller holding arm 110 slides along the longitudinal direction of the arm holder 111. The left end of the arm holder 111 is fixed to a shaft 112.
Both ends of the shaft 112 are supported by side plates (not shown). The rotation of the shaft 112 is regulated by means described later, so that the guide roller holding arm 110 is held at a fixed position together with the arm holder 111 as long as the shaft 112 does not rotate.

An arm home position sensor 122 for positioning a predetermined home position of the guide roller holding arm 110 in the direction of the arrow 503 is mounted on the upper surface of the arm holder 111. The arm home position sensor 122 is used for the guide roller holding arm 1.
10 for detecting the rear end portion, and outputs detection information to the control device 128 as shown in FIG.

In this embodiment, when the arm home position sensor 122 detects the rear end of the guide roller holding arm 110, the position of the guide roller holding arm 110 occupies in the thin paper mode in which thin paper is used as paper. This is the home position of the arm 110. At this time, the disk body 14 is located at a position indicated by a symbol R described later, that is, at the first position described in the first embodiment.

As shown in FIG. 7, the operation panel 124 of the stencil printing apparatus has a paper selection key 125 that can be selected by the operator according to the thickness of the paper, a numeric key 126 for inputting the number of prints, and a printing operation. A display unit 127 for displaying the number of prints by an LED. Here, paper selection key 1
Reference numeral 25 includes a thin paper key 125a for selecting thin paper and a thick paper key 125b for selecting thick paper. A. When Using Thin Paper as Paper When using thin paper as paper, when the thin paper key 125a of the paper selection key 125 in the operation panel 124 is pressed, a signal from the operation panel 124 is input to the control device 128, and the guide roller in FIG. When the rear end of the holding arm 110 is positioned diagonally above and to the left of the arm position sensor 122, a drive command signal is output to the stepping motor 121 shown in FIG. 4 and 5, the stepping motor 121 is driven to move the guide roller holding arm 110 along the arm holder 111.
2 and stops at the position of the detection.

This stop position is the position where the discharge roller lifting prevention guide roller 14 is indicated by the symbol R in FIG. 4, and this position R corresponds to the first position in the first embodiment. This is an angle at which the prevention guide roller 14 is opened at a position downstream of the printing pressure nip portion B with the axis O8 of the printing pressure cylinder 8 as a center, and the separation angle θ from the printing pressure nip portion B is within 30 degrees. .

The printed paper 12 is rotated by the printing pressure drum 8 with the leading end portion clamped by the paper clamper 11 to reach the portion E due to the presence of the guide roller 14 for preventing the rising of the discharged paper at the position R.

In the section E, the paper clamper 11 is changed from "closed" to "open" by a clamper opening / closing mechanism (not shown). The paper 12 already printed at that time is located between the outer surface 9a of the printing pressure cylinder 8 and the guide roller 14 for preventing the ejection of the paper, and the printing pressure cylinder which rotates while being slightly sandwiched between the two. Since the conveying force is applied by the sheet 8, it is possible to prevent a paper discharge winding jam in which the sheet 12 sticks to the outer periphery of the plate cylinder 2.

When the guide roller 14 for preventing the paper ejection rising is in the position R, that is, the first position, the interval F between the tooth tip of the paper ejection rising prevention guide roller 14 and the outer surface 9a is determined by the printing drum 8 It is set to be 0 to 3 mm in a state pressed toward 1.

A mechanism for adjusting the interval F will be described. A shaft 112 is fixed to an end of the arm holder 111 opposite to the printing cylinder 8. Both ends of the shaft 112 are pivotally attached to side plates (not shown). One end of the arm 113 is fixed to one end of the shaft 112. The other end of the arm 113 is urged upward by an elastic spring SP1. Due to the contracting force of the spring SP1,
The arm 113 tries to rotate by receiving a clockwise moment about the shaft 112, but the adjusting screw shaft 1
The rotation thereof is prevented by abutting on.

The adjusting screw shaft 114 is screwed to a fixed bracket 116 integral with the immovable member.
By rotating the arm 113, the arm 113 can be rotated about the shaft 112 to adjust the interval F.

Here, the shaft 112, the arm 113, the adjusting screw shaft 114, the fixed bracket 116, the spring SP1 and the like move the guide roller 14 for preventing the ejection of the paper and lift the gap F between the shaft and the outer surface 9a of the printing cylinder 8. An adjusting means for adjusting is constituted.

The adjusting screw shaft 114 with the arm 113 in between
A stopper 117 is fixed to a non-illustrated immovable member at a portion opposite to the above. The stopper 117 is the adjusting screw shaft 1
The guide roller 14 is provided to prevent the paper ejection lifting prevention guide roller 14 from hitting the print drum 1 on the contrary by excessively pressing the paper roller 14. When the interval F is adjusted to an appropriate value of 0 to 3 mm, a gap γ is secured between the arm 113 and the stopper 117.

Since the gap γ is provided in this manner, the guide roller 14 for preventing the ejection of the paper from being lifted and the outer surface 9a of the printing cylinder are required.
When the jammed paper enters between them, the guide roller 14 for preventing the discharge rising rises to escape upward to prevent damage to the guide roller 14 for preventing the discharge rising and the outer surface 9a of the printing cylinder 8. The stopper 11 is moved from the shaft 112 as a swing fulcrum.
Since the distance from the shaft 112 to the guide roller 14 for preventing the paper ejection from rising is increased with respect to the distance up to 7, the clearance F is increased even if the size of the gap γ is small. Can be.

In the second embodiment, FIG.
As shown in FIG.
The dimensions H, the outer diameter J, the thickness of the disk 14a, and the like are all the same as those in the above-described first embodiment, and a description thereof will be omitted. B. When using thick paper as paper When using thick paper as paper, the thick paper key 125 among the paper selection keys 125 in the operation panel 124 shown in FIG.
Press b. Then, from the control device 128 shown in FIG.
A drive command is output to the stepping motor 121, and the stepping motor 121 rotates in a direction opposite to the rotation direction when the guide roller holding arm 110 is lowered obliquely to the lower left as in the case of using the thin paper.
The amount of rotation at this time follows control information stored in the control device 128 in advance.

For example, by driving the stepping motor 121 by a predetermined number of steps starting from the R position which is the home position in FIGS. 4 and 5, the guide roller holding arm 110 moves diagonally to the upper left along the arm holder 111. And stop. This stop position corresponds to the third position occupied by the guide roller 103 for preventing the lifting of the thick paper in the first embodiment, and is the position indicated by the symbol S in FIGS. In this position S, the discharge roller lifting prevention guide roller 14 has a lower portion of its outer diameter portion located above the horizontal line KK and downstream of the printing pressure nip portion B in the rotation direction of the printing drum 1, the printing pressure cylinder 8 and the like. This is a position where the separation angle β is within 45 degrees in the space position on the side. FIG.
In this case, even when the thick paper floats above the position indicated by reference numeral 12 ', the paper ejection lifting prevention guide rollers 14 at the S position (third position) press and transport the paper.

In this embodiment, the thin paper key 12 of the paper selection key 125 on the operation panel 124 shown in FIGS. 6 and 7 is used in accordance with the thickness of the paper used for printing.
By pressing 5a or the thin paper key 125b according to the thickness of the paper, as described in the first embodiment,
The guide roller 14 can be easily positioned at the first position for thin paper and at the third position for thick paper.

In this case, in the case where thick paper is used, in the first embodiment, after removing the printing drum 1 in advance, the holding arm 18 is rotated to move the ejection floating prevention guide roller 14 to the second position. Had to be evacuated,
In the second embodiment, operability is improved because only a switch operation is required.

As a guide for switching between thick paper and thin paper, when the paper basis weight is 110 kg or less, the paper is processed as a predetermined thin paper and the thin paper key 125a is pressed. When the paper weighing is 135 kg or more, it is processed as a predetermined thick paper, and the thick paper key 125b
push. In addition, the cardboard key 125b is pressed also for small-sized cardboard special paper such as postcards, envelopes, and beer tickets.

In this way, the guide roller 14 for preventing the ejection of the paper from being lifted up is supported by the guide roller holding arm 110 which is a switching means driven by the stepping motor 121, combined with the arm home position sensor 122, and discharged by using the control device 128. Since the position of the guide roller 14 for preventing the paper lifting is controlled, it is possible to easily handle both thick paper and thin paper with only a switch.

Further, in FIG.
A sheet thickness detection sensor 130, which is a transmission type sensor, is provided at a position near the upstream side of the registration roller 13 as a sheet detection unit for detecting the thickness of the sheet.

The control device 128 previously shown in FIG. 6 uses the transmission voltage detected by the paper thickness detection sensor 124 as the reference voltage when the paper weighing 110 kg, which is the range of thin paper, is passed.
The guide roller 1 for preventing the rising of the discharged paper is determined based on the reference voltage.
Set the position of 4.

Thus, even if the operator does not select and operate the sheet selection key 125 each time, the switching means described above is operated according to the judgment of the control device 128 as the control means, and the discharge roller floating prevention guide roller 14 is operated. Can be positioned at any one of the first position suitable for thin paper and the third position suitable for thick paper.

For example, if the transmission voltage of the sheet passing through the portion of the sheet thickness detecting sensor 130 is equal to or less than the reference voltage,
The control device 128 outputs a control signal to the arm stepping motor 121, and drives the arm stepping motor 121 so that the ejection floating prevention guide roller 14 moves to the first position, that is, the R position for thin paper.

If the transmission voltage of the sheet passing through the portion of the sheet thickness detecting sensor 130 exceeds the reference voltage, the control device 128 controls the arm stepping motor 121.
Control signal is output to the
4 drives the arm stepping motor 121 so as to move to the third position, the S position for thick paper.

Without operating the paper selection key 125,
It is possible to automatically select the thickness of the paper and to move the guide roller 14 for preventing the rising of the discharged paper to an appropriate position, thereby preventing the user from making mistakes in entering the guide roller and preventing the rising of the guided roller for preventing the rising of the discharged paper when a thick paper jam occurs. It is possible to prevent a phenomenon in which the piercing member 14 pierces the surface 9a of the printing cylinder 8 beforehand.

In the second embodiment, there is no need to rotate the holding arm 18 as in the first embodiment. The pawl 61 is used to hold the guide roller
It is possible to be installed at an upper position along the 0 or the arm holder 111. [Third Embodiment] FIG. 8 illustrates another embodiment different from the above-described two embodiments. 8, the same members as those in FIGS. 1 and 4 are denoted by the same reference numerals as in FIGS.

In the first embodiment described above, the guide roller 103 for preventing the floating of the thick paper is set to the horizontal line KK when the thick paper is passed.
And the separation angle β is within 45 degrees. In the second embodiment, when the thick paper is passed, the ejection floating prevention guide roller 14 is positioned above the horizontal line KK and the separation angle β. This is an example in which the guide roller is moved together with the guide roller holding arm 110 so that β is located within 45 degrees.

On the other hand, in the present embodiment, the guide roller 154 for preventing the ejection of paper from being lifted is disposed substantially at the center of the printing cylinder 8 in the axial direction.
At the position immediately after the printing pressure nip portion B, the surface 9 of the printing cylinder 8
When the sheet to be used is a thin sheet, the sheet is passed below the ejection floating prevention guide roller 154, and the printing pressure cylinder 8 and the ejection lifting prevention guide roller 154 are moved to the first position. The thin paper is conveyed in a state sandwiched between them, and when the paper to be used is thick paper, the thin paper passes above the guide roller 154 for preventing the rising of the discharged paper.

Since the thick paper has a stiffness as indicated by reference numeral 12 ', it is lifted considerably above the horizontal line KK especially in the case of a solid image or at a high temperature and a low speed. A duct 102 is provided integrally with the air knife fan 101 in accordance with the configuration shown in FIG. 1 so as to guide the air toward the printing pressure nip portion B in order to prevent such a thick paper 12 ′ from being lifted.

From the outlet of the air from the duct 102, as indicated by the arrow Q, air is blown toward the position of 8 o'clock just after the printing pressure nip B on the rotation direction of the plate cylinder 2. You. This air travels along the peripheral surface of the plate cylinder 2 toward the printing nip B, and acts as a result to press the thick paper 12 ′ against the outer surface 9 a of the printing cylinder 8.

The guide roller 154 for preventing the ejection of the paper from being lifted is
As in the case of the first and second embodiments, as shown in FIG. 8, a disk made of a thin metal plate having uneven jagged teeth on the outer periphery and a resin holder holding the disk as shown in FIG. As in the case of the guide roller 14 for preventing the rising of the sheet shown in FIG. 2, two rollers facing the width direction of the sheet perpendicular to the sheet conveyance direction are provided as a pair, and rotate around the shaft 17 '. It is kept possible.

The shaft 17 'is fixed to one end of the guide roller holding arm 152. Guide roller holding arm 152
Is fixed to a support shaft 153, and the support shaft 15
Reference numeral 3 is supported by a side plate (not shown), and holds the guide roller 154 for preventing the ejection of the paper at a predetermined position (first position). In addition, the guide roller 15 for preventing the ejection of the paper
The distance F 'between the outer surface 4a and the outer surface 9a of the printing cylinder 8 can be adjusted by adjusting means (not shown) or adjusting means similar to the adjusting means described above with reference to FIGS. .

The guide roller 154 for preventing the ejection of the paper from being lifted up
The outer diameter is set so that when the paper is thin paper, the thin paper passes under the discharge lifting prevention guide rollers 154, and when the paper is thick paper, the thick paper can pass over the discharge lifting prevention guide rollers 154. The size is 15 mm or less in diameter. Further, the separation angle of the guide roller 154 for preventing the ejection of the paper from the printing pressure nip portion B around the axis O8 of the printing pressure cylinder 8, that is, θ in FIG. 8 is within 30 degrees, and the horizontal line KK It has been confirmed by experiment that it is better to be located below.

A paper thickness detecting sensor 130 is arranged at an upstream position of the registration roller 13. Further, a stepping motor 150 is provided as a means for driving the pair of upper and lower registration rollers 13, and a roller below the pair of registration rollers 13 is provided with a registration roller stepping motor 150.
And an endless belt 151 is connected between them.

In the present embodiment, FIG.
The conveyance of the sheet is controlled using the control system shown in FIG. In the control system shown in FIG. 9, the control device 128 ′ receives input of information from the operation panel having the same configuration as the operation panel 124 shown in FIG. 7 and the sheet thickness detection sensor 130 and controls the registration roller stepping motor 150. It outputs a signal. A. When thin paper is used as the paper The thin paper key 12 of the paper selection key 125 on the operation panel 124
If the controller 128 ′ selects 5a or the controller 128 ′ determines that the sheet is thin according to the detection information from the sheet thickness detection sensor 130, the controller 128 ′ rotates the stepping motor 150 at a specific timing in the thin sheet mode. Then, the sheet 12 is sent out from the registration roller 13. Paper 12 made of thin paper sent from registration roller 13
Is locked at the upstream position D by the paper clamper 11 and sent to the printing pressure nip B as it is, where a print image is formed.

The paper 12 rotates together with the impression cylinder 1 while the leading end of the paper 12 is clamped by the paper clamper 11, and in the E section, the paper leading end clamper 11 is changed from "closed" to "open" by a clamper opening / closing mechanism (not shown). Is done. At this time, the printed paper 12 is located between the outer surface 9a of the impression cylinder 8 and the guide roller 154 for preventing the ejection of the paper, and is lightly sandwiched between the outer surface 9a and the guide roller 154 for preventing the ejection of the paper. Impression cylinder 8 which rotates in the state
As a result, the printed paper 12 made of thin paper is prevented from sticking to the outer periphery of the cylindrical plate cylinder 2, thereby preventing the occurrence of a paper discharge winding jam.

After the paper clamper 11 is in the “open” state at the portion E, if the printed paper 12 is thin paper or the printed image is a solid image, it is wound around the outer periphery of the cylindrical plate cylinder 2. It is stuck on the surface of the stencil sheet 3 with ink adhesive force and slightly rolls up as shown by the broken line in FIG. 1, but still does not roll up more than a certain amount and does not become a jam. It is guided by the scraper 15 and is guided correctly on the suction-type transport unit 16. B. When using thick paper as the paper: the thick paper key 12 of the paper selection key 125 on the operation panel 124
5b, or when the control device 128 'determines that the paper is thick paper based on the detection information from the paper thickness detection sensor 130, the control device 128' rotates the stepping motor 150 at a specific timing in the thick paper mode. Then, the thick paper 12 ′ is sent out from the registration roller 13. Paper 12 ′ sent from registration roller 13
The leading end is not locked by the paper clamper 11 at the upstream position D, and is sent to the printing pressure nip B as it is, where a print image is formed.

A portion indicated by reference numeral 12 ', which is a printed thick paper, is not clamped by the paper clamper 11, but has a stiffness in the paper. The sheet is conveyed above the roller 154 and guided, and is correctly guided on the suction-type conveying unit 16 via the scraper 15.

In the configuration shown in FIGS. 1 and 4, a registration roller stepping motor 150 may be provided as a driving means of the registration roller 13 as in FIG.

In these examples, by providing the registration roller stepping motor 150, the opening / closing timing of the paper clamper 11, for example, the closing position in the section D is set in accordance with the driving timing of the stepping motor 150, so that the control can be accurately performed. Can be rolled.

[0125]

According to the first aspect of the present invention, when thin paper is used as printing paper, the disc is placed at the first position to prevent the thin paper from winding up and to use thick paper as printing paper. By disposing the disk body at the second position at the time of printing, roller trace contamination on the thick paper is avoided.

According to the second aspect of the present invention, by positioning the disk at the third position, even when the disk is jammed, the gap between the disk and the impression cylinder is large. It is possible to prevent the disk body from colliding with the impression cylinder and damaging the surface of the impression cylinder, or the image surface being lost due to the depression of the surface of the impression cylinder.

According to the third aspect of the present invention, since the disk body rotatably held at the third position is provided by using the duct of the air knife fan, a member dedicated to supporting the disk body is provided. It is not necessary to increase the number of parts as compared with the case of providing a simple configuration.

According to the fourth aspect of the present invention, it is possible to easily handle both thick paper and thin paper simply by operating the switch, and the operator can position the disk body without entering a dangerous printing apparatus. Can be switched safely and easily for both thick and thin paper.

According to the fifth aspect of the present invention, since the thickness of the sheet is automatically detected and the position of the disk body is made variable, it is possible to eliminate an operator's setting error and improve the reliability of the printing apparatus. I do.

According to the sixth aspect of the present invention, by setting the outer diameter of the disk to 15 mm or less, the disk can be provided at the first position as close to the printing pressure nip as possible. This makes it possible to keep the angle θ of the disk body from the printing pressure nip portion on the printing pressure cylinder within 30 degrees, and even during the solid image of thin paper, the solid winding degree α after opening the paper clamper α ( 1 can be reduced, the discharge paper curling prevention ability is high, and the ink transfer amount does not increase.

Also, by switching to the second position, the separation angle β of the disc on the print drum is set to 45 degrees or less and the lower part of the disc is positioned higher than the printing pressure nip when the thick paper is passed. By doing so, the pressure in contact with the rollers can be considerably reduced, and contamination of the roller traces in the character image can be prevented. Further, even when the disc is jammed, the gap between the disc and the impression cylinder is large, so that the disc does not collide with the impression cylinder and the dent does not occur on the surface of the impression cylinder. Disappears.

According to the seventh aspect of the invention, by setting the outer diameter of the disk body to 15 mm or less, the disk body can be provided as close to the printing pressure nip as possible. The angle of separation θ of the disk body from the printing pressure nip portion can be made within 30 degrees, and even during the solid image of thin paper, the solid winding degree α after opening the paper clamp (the winding line indicated by the broken line in FIG. 8) Amount) can be reduced, so that the paper ejection curling prevention ability is high and the ink transfer amount does not increase. In addition, by providing only one disk body, there is no need to provide a means for changing the position of the disk body for each paper thickness such as thick paper or thin paper, and when printing with a thin paper solid image at a fixed position, winding up occurs. In the case of thick paper, the disc body comes into contact with the back side of the printing surface and feeds the paper, so that the roller surface is not stained on the image surface.

According to the eighth aspect of the present invention, since the interval between the paired disk bodies is set to an appropriate value, the disk is adhered to the print drum at the central portion in the axial direction of the print drum by making the interval too large. An appropriate curling prevention function without preventing the ability to prevent the curling phenomenon of discharged paper from being easily rolled up and without losing the effect of pressing the paper stably because the discs are too close to each other. Can be fulfilled.

According to the ninth aspect of the present invention, by contacting the elastic roller with the outer peripheral portion of the disk, ink attached to the disk can be transferred and adsorbed and removed from the disk. Regardless of the thickness, it is possible to prevent roller trace stains that further transfer from the disk to the image surface of the sheet.

According to the tenth aspect of the present invention, since the material of the auxiliary roller in contact with the disk is made of foam, ink can be sucked into the air portion of the foam, and no ink adheres to the disk. Can be maintained for a long time, and the dirt and stains on the image surface of the paper can be prevented for a long time.

According to the eleventh aspect of the present invention, since the outer diameter of the auxiliary roller is one to three times the outer peripheral portion of the disk, the area of ink absorption by the auxiliary opening is large, and the ink adheres to the disk. It is possible to maintain the state of no paper for a long time, and to prevent the roller trace stain on the image surface of the paper for a long time.

According to the twelfth aspect of the invention, it is possible to adjust the distance between the disk and the impression cylinder appropriately according to the type and thickness of the printing paper.

According to the thirteenth aspect of the present invention, the roll-up jam is prevented by the pressing action of the disc only when the printing paper is thin paper, and when the printing paper is thick paper, the disc is moved to a position where it does not interfere with the thick paper. By retreating, it is possible to prevent damage to the disk and the printing cylinder due to dirt on the roller trace due to the disk and jam.

[Brief description of the drawings]

FIG. 1 is a front view of an essential part of a stencil printing apparatus according to a first embodiment, in which a disk body having an uneven outer peripheral portion is provided near a nip portion formed by pressing a printing drum and a printing cylinder.

FIG. 2 is a plan view illustrating a disk body and a supporting portion thereof in FIG.

FIG. 3 is a front view showing an example of a means for adjusting an interval F in the configuration shown in FIG. 1;

FIG. 4 is a front view of a main part of a stencil printing apparatus according to a second embodiment, in which a disk body having an uneven outer peripheral portion is provided near a nip portion formed by pressing a printing drum and a printing cylinder.

FIG. 5 is a plan view illustrating a disk body and its supporting portion in FIG.

FIG. 6 is a block diagram of a control system for controlling switching between a first position and a second position according to the thickness of printing paper in the second embodiment.

FIG. 7 is a plan view of an operation panel.

FIG. 8 is a front view of a main part of a stencil printing apparatus in which a disk body having an uneven outer periphery is provided in the vicinity of a nip portion formed by press contact between a printing drum and a printing cylinder according to a third embodiment.

FIG. 9 is a block diagram of a control system for controlling opening and closing of a paper clamper according to a thickness of a printing paper in the third embodiment.

FIG. 10 is a diagram illustrating a state of printing paper in the vicinity of a pressure contact portion between a printing drum and a printing cylinder.

FIG. 11 is a plan view illustrating the state of a solid image on printing paper.

FIG. 12 is an explanatory view of a related art regarding a means for preventing a printing paper from winding up in a printing pressure nip portion.

FIG. 13 is a view for explaining a conventional proposal technique relating to a guide roller system for preventing a paper ejection rising.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Print drum 12, 12 'Printing paper 14 Guide roller for preventing ejection of paper ejection 103 Guide roller for preventing ejection of thick paper 154 Guide roller for preventing ejection of paper ejection

Claims (13)

[Claims] 1. A porous cylindrical printing drum, which is formed by winding a perforated plate-making plate (master) around an outer peripheral surface thereof, and is provided so as to be able to freely contact and separate from the printing drum. A printing pressure cylinder as a diameter pressing means, the printing pressure cylinder having a clamper for holding the leading end of the paper supplied from the paper feeding means to the printing pressure cylinder, and placing the paper on the printing drum. A stencil printing apparatus that presses the printing impression cylinder through, and moves ink from the master perforated portion to the paper from within the printing drum to perform printing, wherein the printing press is disposed at a substantially central portion in the axial direction of the printing impression cylinder. ,
In the direction of rotation of the printing cylinder, move to a first position very close to the surface of the printing cylinder at a position immediately after the printing pressure nip portion and to a second position not interfering with the rotation locus of the master clamper of the printing drum. A stencil printing apparatus characterized by having a disc body whose outer peripheral portion is made of irregularities and held as possible. 2. The stencil printing apparatus according to claim 1, wherein the stencil printing apparatus is rotatably held at a third position very close to a rotation locus of the clamper immediately after the printing pressure nip.
A stencil printing machine characterized in that the outer peripheral portion has a disk body having irregularities. 3. The stencil printing apparatus according to claim 2, wherein the disk body having an uneven outer peripheral portion rotatably held at the third position is provided in a part of a duct of an air knife fan. A stencil printing apparatus characterized by the above-mentioned. 4. A stencil printing apparatus according to claim 1, wherein said switching means automatically switches between said first position and said third position by inputting a sheet thickness, and said control means controls said switching means. A stencil printing device, comprising: 5. A stencil printing apparatus according to claim 1, further comprising a sheet detecting means for detecting the thickness of the sheet, and automatically switching between the first position and the third position according to the sheet thickness. A stencil printing machine characterized by the following. 6. The stencil printing machine according to claim 1, wherein the outer peripheral portion of the disk body having irregularities has an outer diameter of 15 mm.
Hereinafter, the first position is an angle opened to the downstream side of the printing pressure nip portion about the axis of the printing cylinder with respect to a line connecting the axis of the printing drum and the axis of the printing cylinder. An angle (θ) formed by a line segment passing through the center of the disk body is within 30 degrees, and the third position is relative to a line connecting the axis of the printing drum 1 and the axis of the impression cylinder. An angle (β) formed by a line segment passing through the center of the disk body, which is an angle opened to the downstream side of the printing pressure nip portion about the axis of the printing drum, is 4
A stencil printing machine wherein the lower portion of the disk body is provided at a position higher than the printing pressure nip portion within 5 degrees. 7. A porous cylindrical printing drum which is formed by winding a perforated plate (master) around an outer peripheral surface thereof, and is provided so as to be able to freely contact with and separate from the printing drum. A printing pressure cylinder as a diameter pressing means, the printing pressure cylinder having a clamper for holding the leading end of the paper supplied from the paper feeding means to the printing pressure cylinder, and placing the paper on the printing drum. A stencil printing apparatus that presses the printing pressure cylinder through the printing drum to move ink from the master perforated portion to the paper from within the printing drum to perform printing, comprising: Has an outer diameter of 15 mm or less, and opens to the downstream side of the printing pressure nip portion about the axis of the printing cylinder with respect to a line connecting the axis of the printing drum and the axis of the printing cylinder. The angle (θ) formed by a line segment passing through the center of the disk body is 3 Within degrees, stencil printing machine upper portion of the disk body and being provided at a position lower than the printing pressure nip. 8. The stencil printing apparatus according to claim 1, wherein a pair of discs each having an outer peripheral portion having irregularities are provided,
A stencil printing machine characterized in that the distance between the pair of stencils is 20 to 150 mm at the center of the printing cylinder in the axial direction. 9. The stencil printing apparatus according to claim 1, wherein an auxiliary roller made of an elastic material is brought into contact with said disk having an outer peripheral portion having irregularities. apparatus. 10. The stencil printing apparatus according to claim 1, wherein an elastic auxiliary roller is brought into contact with said disk having an outer peripheral portion having irregularities, and said auxiliary roller is provided with a foam. A stencil printing apparatus, characterized by using: 11. The stencil printing apparatus according to claim 1, wherein an elastic auxiliary roller is brought into contact with said disk body having an outer peripheral portion having irregularities, and an outer diameter of said auxiliary roller. Stencil printing machine characterized in that the diameter of the stencil is 1 to 3 times the outer diameter of the disk. 12. The stencil printing machine according to claim 1, further comprising adjusting means for adjusting a distance between said disk and said impression cylinder. Printing device. 13. A porous cylindrical printing drum which is wound around a perforated plate-making plate (master) around its outer peripheral surface, and is provided so as to be able to freely contact and separate from said printing drum, and is substantially the same as said printing drum. A printing pressure cylinder as a diameter pressing means, the printing pressure cylinder having a clamper for holding the leading end of the paper supplied from the paper feeding means to the printing pressure cylinder, and placing the paper on the printing drum. In the printing method in which the printing cylinder is pressed through the printing drum and ink is transferred from the master perforated portion to the paper from within the printing drum to perform printing, the printing cylinder is rotated when predetermined thin paper is used as printing paper. In the direction, at the position immediately after the printing pressure nip portion, the thin paper is conveyed by pressing the thin paper toward the printing pressure cylinder side by a disk body having irregularities at the outer peripheral portion, and when using a predetermined thick paper as printing paper, the disk body Is in a non-interference state with the cardboard Or a printing method, wherein the disc is positioned between the cardboard and the printing cylinder at a position immediately after the printing pressure nip, and the cardboard is transported while supporting the cardboard from below.