JP2002137363A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer not liable to be damaged at a distal end of a sheet in a sheet conveying clamping operation for holding the end of the sheet by a holding member of an impression cylinder. SOLUTION: Like the case of a double-side printing or the like, even when same sheet is passed twice, stoppers 2a of a sheet clamper 2 are disposed asymmetrically to a center O of a sheet conveying direction when the sheet is collision-contacted with the stoppers 2a of the clamper 2 and clamped. Accordingly, same part of a distal end of the sheet collision-contacted with the stopper 2a by first time passing is not again collision contacted with the stopper 2a so that an end damage of the sheet due to the collision contact does not become apparent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus such as a stencil printing apparatus using an impression cylinder.

[0002]

2. Description of the Related Art In a stencil printing apparatus as an example of a printing apparatus, a stencil printing apparatus is rotatable around a rotation center axis, and a plate cylinder for winding a master made on an outer peripheral surface; A press drum which is rotatable in a direction opposite to the rotation direction of the drum, has a paper clamper (holding member) for holding the leading end of the fed paper, and has an impression drum having substantially the same diameter as the outer diameter of the plate drum. Are known (see, for example, JP-A-5-201115 and JP-A-8-183166). The above-mentioned impression cylinder has a concave portion provided on a part of its outer peripheral portion in order to avoid interference with a master clamper which holds the tip of a master provided on the outer periphery of the plate cylinder, so that a mark on the plate cylinder is formed. Since the amount of movement when the pressure is turned on / off can be reduced, the noise of the printing pressure can be reduced, and the noise of the stencil printing apparatus can be reduced.

The above-mentioned paper clamper is disposed in a concave portion of the impression cylinder and can be freely opened and closed. Such a paper clamper is also called a “holding claw”, and has a function of holding and holding the leading end of the fed sheet (hereinafter, may be referred to as “holding” or “clamping”). have. The leading end of the fed sheet is conveyed by a rotating impression cylinder while holding the sheet by a paper clamper, and the sheet can be pressed against the plate cylinder to perform printing. Prevents the so-called "paper discharge (paper) roll-up" that can not be peeled off by the paper discharge nail or peeling nail while sticking to the paper, or improves the positional accuracy (registration accuracy) of the printed image in the paper transport direction of the paper Can be planned.

Referring to FIGS. 12 to 21, in a paper holding device of an impression cylinder provided with a paper clamper, each operation of paper clamping at the time of paper feeding, clamping, and paper discharging and paper transporting operation at that time. Will be described.

[0005] For example, in a stencil printing apparatus as shown in FIG.
For the purpose of improving the registration accuracy and the like, an impression cylinder 20 provided with a paper clamper 30 as a pressing means, that is, a so-called “paper holding impression cylinder method” is used.

As shown in FIG. 12, the impression cylinder 20 has an outer diameter D (diameter) equal to the outer diameter D (diameter) of the plate cylinder 22. When the plate cylinder 22 makes one rotation, as shown in FIG. Impression cylinder 2
Zero also makes one revolution. For this reason, as shown in the figure, the paper clamper 3 clamps the leading end of the fed paper P.
0 can be disposed on the impression cylinder 20, and the paper P is fed while the leading end of the paper P is abutted against the paper clamper 30, so that the registration accuracy of the paper P can be improved. In FIG. 12, the paper ejecting claws 44 also called the paper clamper 30 and the scraper are schematically and simplified.

As shown in FIGS. 13 to 15, a clamp device 28 includes an openable and closable paper clamper 30 for clamping the leading end of the fed paper P, and a paper clamper 3.
0 is fixed with a screw, and a shaft 36 extending in the direction of one generatrix of the outer periphery of the impression cylinder 20 and a cam (not shown) fixedly provided on the apparatus main body side to open and close the paper clamper 30 are driven. )
A cam follower 37 that engages with the cam; an arm 39 fixed between the shaft 36 and the cam follower 37 to transmit the movement of the cam to the paper clamper 30; A base 35 for rotatably supporting both ends of the paper clamper 36 by a predetermined angle, a magnet 34 for holding the paper clamper 30 at its closing position by its magnetic force, and a tension spring 38 for urging the paper clamper 30 in a closing direction. It is configured.

The paper clamper 30 lifts the printed paper P from the impression cylinder 20 when the paper claw 31 is clamped by the paper claw 31 and comes to the position of the paper discharge claw 44. And a stopper claw 33 which abuts on the leading end of the fed sheet P to position the leading end of the sheet P. As described above, the paper clamper 30 is formed substantially integrally with the paper pawl 31, the kick-up pawl 32, and the stopper pawl 33 by cutting and bending a sheet metal.

The magnet 34 is fixed to the upper portion of the base 35, and holds the leading end of the sheet P clamped by the sheet claw 31 in the closed position by its magnetic force. The base 35 is formed with a plurality of cutout portions 34a so that the paper claws 31, the stopper claws 33, and the kick-up claws 32 of the paper clamper 30 that swings open and close do not interfere with each other. The tension spring 38 is provided between the portion of the arm 39 near the cam follower 37 and the pin 20 implanted in the end plate 20 a of the impression cylinder 20.
b. The paper clamper 30 opens and closes according to the cam curve of the cam described above, but is closed by the urging force of the tension spring 38 when closing.

With the structure of the clamp device 28 described above,
The paper clamper 30 opens and closes while swinging about the shaft 36 in accordance with the movement of the cam described above. At this time, the sheet clamper 30 rotates the sheet claw 31 and the kick-up claw 32 at a predetermined angle around the one shaft 36 as a fulcrum, in other words, swings, so that when the sheet clamper 30 clamps the sheet P, Is opened to the extent that the tip of the riser claw 32 does not protrude from the outer peripheral surface of the impression cylinder 20 (see FIG. 17). Then, the paper clamper 30
Is a pair of registration rollers 25a, 25b
Open at a predetermined timing, for example, the rotation position of the paper clamper 30 in the impression cylinder 20 shown in FIG. 12 (hereinafter sometimes referred to as “paper clamp position”) to clamp the leading end of the paper P sent from After the leading end of the paper P is abutted against the stopper claw 33 of the paper clamper 30, FIG.
The paper P is clamped by the paper claw 31 of the paper clamper 30 while the paper P is conveyed at a paper conveyance speed such that a predetermined flexure PA as shown by a two-dot chain line is formed. The sheet clamper 30 is closed at a predetermined timing after exiting the downstream ends of the pair of upper and lower guide plates 40 and 41 shown in FIG.

The paper clamper 30 is laid out with the leading edge of the paper pawl 31 as close as possible to the pressing point C in order to minimize the paper leading edge margin length AL shown in FIG. A few mm (approximately 2 to 5 mm)
It is designed to clamp the middle part.

Next, the paper clamper 30 rotates in a state where the leading end of the paper P is clamped, that is, the impression cylinder 20 rotates while holding the paper P on its outer peripheral surface, and near the rotational position shown in FIGS. As shown in FIG. 14, the leading end of the sheet P is positioned between the outer peripheral surface of the plate cylinder 22 and the impression cylinder 20 as shown in FIG.
And the leading edge of the paper P is
The stencil printing is performed in a nip portion N formed by pressing the outer peripheral surface of the plate cylinder 22 and the outer peripheral surface of the impression cylinder 20 via the paper P.

The paper clamper 30 passes through the nip portion N as shown in FIG. 20 and immediately before reaching a paper discharge claw 44 at a rotational position (hereinafter sometimes referred to as a “paper discharge position”) shown in FIG. Is opened again in the vicinity of the position C, whereby the leading end of the printed paper P is released from the paper claw 31 of the paper clamper 30 and then the paper clamper 30 is further opened, so that the printing is performed by the kick-up claw 32 as shown in FIG. The leading end of the sheet P thus picked up is picked up, the leading end of the sheet P is transferred to the sheet ejection claw 44, and the sheet ejecting / conveying device 49 (see FIGS. 13 and 14) including a belt for rotating the sheet P thus ejected and a suction fan. Reference).

As described above, the rotational position of the paper clamper 30 on the impression cylinder 20 sequentially changes from → to →,
Since the leading end of the sheet P is discharged at a position beyond the rotation position where the ink is transferred to the sheet P, the sheet P does not wind up on the plate cylinder 22 due to the adhesive force of the ink. The opening / closing timing position of the sheet clamp position of the sheet clamper 30 at the rotation position of the impression cylinder 20 prevents the leading end of the sheet P from being erroneously clamped by the sheet clamper 30 and prevents the plate cylinder 22 from being moved near the nip portion N. In order to prevent interference with the outer peripheral surface or the like, the guide plates are set so as to be as close to the downstream ends of the pair of guide plates 40 and 41 as possible.

Incidentally, in the case of the paper clamper 30 in which the paper clamper 30 clamps a part of the leading end of the paper P about several mm (approximately 2 to 5 mm), the leading end of the paper P is a stopper of the paper clamper 30. When the paper conveyance speed at the time of colliding with the claw 33 is lower than the peripheral speed of the impression cylinder 20, the leading end of the paper P to be clamped by the paper clamper 30 is positioned between the outer peripheral surface of the plate cylinder 22 and the outer periphery of the impression cylinder 20. The paper P may come off from the paper clamper 30 before the surface is pressed, or a gap may be formed between the stopper claw 33 and the leading end of the paper P, and the leading end position of the paper P with respect to the stopper claw 33 may be shifted. As described above, the leading end of the sheet P has the sheet clamper 3.
When the paper P is not completely clamped since the paper P is not clamped because the leading end of the paper P is stuck to the outer peripheral surface of the plate cylinder 22 and cannot be peeled off by the paper discharge claw 44 or the kick-up claw 32, the above-described jam called paper discharge curl occurs. Even if the leading edge of the paper P does not completely come out of the paper clamper 30, the stopper claw 3
When the leading end position of the sheet P with respect to the sheet 3 is shifted, the print image G in the sheet transport direction X of the printed sheet P is
Or the positional accuracy (resist accuracy) of the device may be deteriorated.

In order to solve such a problem, in practice, as described above, the leading end of the sheet P is
By setting the paper transport speed at the time of contact with the zero stopper claw 33 to be higher than the peripheral speed of the impression cylinder 20, a predetermined bending PA is caused near the holding portion of the leading end of the paper P by the paper clamper 30. In this case, a paper transport speed control method is employed in which no force acts such that the leading end of the paper P comes off from the paper clamper 30.

In the case of adopting such a paper transport speed control method, before the bending PA forming portion near the leading end portion of the paper P is pressed by the nip portion N, the master having made the plate on the outer peripheral surface of the plate cylinder 22 is finished. 23 may be in contact with the nip portion N since the portion of the sheet P where the flexure PA is formed becomes stained with ink oozing out of the master 23 that has been made and forms a double image. A guide member 160a serving as a paper guide means for guiding the paper P on the paper transport path so that the bent portion PA of the paper P before reaching the nip portion N does not come into contact with the stencil master 23 on the plate cylinder 22.
(Shown only in FIG. 13). Reference numeral 161 denotes a flexible member provided at a downstream end of the guide member 160a in the sheet transport direction X.

On the other hand, when trying to reduce the leading edge margin length AL of the sheet, the leading end D of the sheet pawl 31 projects outward from the outer diameter D of the impression cylinder 20 to cause the master 2 on the plate cylinder 22 to complete the plate making operation.
3 and the leading end D of the paper nail 31 hits the master 23 on the same part every rotation, so that the master 23 on the same part is torn. When the master 23 after plate making is torn in this way, the ink supplied to the outer peripheral surface of the plate cylinder 22 will protrude from the torn portion, and the protruding ink stains the paper claw 31 to form the paper P. In order to prevent the front end D of the paper pawl 31 of the paper clamper 30 from hitting the master 23 on the plate cylinder 22, the paper clamp 3
Numeral 0 is inclined and disposed on the center side of the impression cylinder 20 so that the leading end D of the paper claw 31 falls within the outer diameter dimension D. It has a layout structure in which it is bent slightly to the side and clamped.

[0019]

However, in the case of the conventional structure around the paper clamper 30, the following inconveniences and problems occur.

(1) Raising claw 32 of paper clamper 30
21, the paper nail 31 is opened more than necessary as shown in FIG. 21, and the paper nail 31 interferes with the tip of the paper ejection nail 44. To avoid this, as shown in FIG. An escape 31a is formed in the paper nail 3
1 has a comb-like shape whose free end is open. On the other hand, when the leading end of the sheet P is clamped by the sheet clamper 30, the sheet clamper 30 is used to increase the positioning accuracy.
The stopper claw 33 is also formed in a comb-like shape, that is, intermittently in the sheet width direction corresponding to the above-described sheet claw 31, and the leading end of the sheet P is It will partially hit the portion where the nail 33 exists. However, it is also common knowledge in this type of technical field that it is easier to obtain positional accuracy when the leading end of the sheet is not in full surface contact but in partial contact with the stopper claw before that. At this time, it is common design knowledge in this technical field to form and dispose the stopper claws 33 symmetrically with respect to the center in the sheet conveyance direction in consideration of the balance of the right and left centers of gravity and the like.

However, as described above, the paper transport speed when the leading end of the paper P comes into contact with the stopper claw 33 of the paper clamper 30 is set to be higher than the peripheral speed of the impression cylinder 20. (See FIG. 22... 50 is a flaw portion). Such a flaw 50 is not so conspicuous in one pass of paper, but the same portion of the leading end of the paper P is applied to the stopper claw 33 by two times, for example, in the case of performing double-sided printing in which the same paper is passed twice. It becomes noticeable when hit. This is also not very noticeable when only one sheet is used. However, since many types of stencil printing apparatuses are often used to perform printing, a double-sided printing is performed as shown in FIG. As a result, stripe-shaped flaws 50 become conspicuous, which impairs the printing finish.

(2) The paper P is a resist roller 25a,
The roller 25 is conveyed by a pair of upper and lower parallel guide plates 40 and 41 to a position where the impression cylinder 20 is clamped by the paper clamper 30 by the registration rollers 25a and 25b.
Separation of paper at the upstream side and the registration roller 25
The wrinkles (waves, curls, and the like) of the paper P generated during the feeding by a and 25b head toward the clamp position as they are. As a result, if the wrinkles (waves, curls, etc.) are large, the leading edge of the paper P does not reliably enter the clamp portion depending on the opening amount of the paper clamper 30.
Since the paper is not clamped properly, it may be stuck to the leading edge of the paper or cause a jam.

(3) As shown in FIG. 24, the stopper claw 33 and the paper claw 31 of the paper clamper 30 are formed in a substantially rectangular shape when viewed from the side.
The paper P sent from the sides a and 25b is
Then, the paper P moves to the paper claw 31 side following the stopper claw 33, and is finally pressed and held by the paper claw 31 that performs the clamping operation. In this case, as shown in FIG. 24A, a joint 51 between the stopper nail 33 and the paper nail 31 is formed.
The paper P advances toward the free end side of the paper pawl 31 without passing through the portion, and is clamped by the paper pawl 31 in this state, so that as shown in FIG.
Etc. may occur. As a result, the paper P
The resist accuracy is also lowered.

After all, in these cases, there is a problem that a flaw is generated at the leading end of the sheet during the clamping operation by the sheet clamper 30.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a printing apparatus in which a front end of a sheet is hardly flawed in a sheet conveying clamp operation for holding the front end of a sheet by a holding member in an impression cylinder.

[0026]

According to the first aspect of the present invention,
A printing cylinder including a plate cylinder for winding a master made on an outer peripheral surface, and an impression cylinder having an openable and closable holding member for holding a leading end of a conveyed sheet and having an impression cylinder opposed to and in contact with the plate cylinder; The holding member has a stopper portion that is formed intermittently in the paper width direction and abuts and positions the leading end of the paper that is fed and conveyed, and a clamp portion that clamps the leading end of the paper, The stopper portion is disposed asymmetrically with respect to the center in the sheet transport direction.

Therefore, even when the same sheet is passed twice, such as in the case of double-sided printing, when the stopper is brought into contact with the stopper of the holding member and clamped, the stopper is positioned at the center in the sheet transport direction. Are arranged asymmetrically with respect to the left and right sides, so that the same portion of the leading end that has hit the stopper portion in the first sheet passing does not hit the stopper portion again, so that the tip flaw caused by the hitting is inconspicuous.

According to a second aspect of the present invention, there is provided a plate cylinder for winding a master made on a peripheral surface, and a holding member which can be opened and closed to hold the leading end of the conveyed sheet, and is in contact with the plate cylinder. An upper guide plate for applying a specific contact pressure to the upper surface of the paper at a paper outlet of a transport path of the impression cylinder toward the holding member.

Therefore, the sheet heading toward the holding member is subjected to specific contact pressure by the upper guide plate and is squeezed, so that there is a wrinkle (wave, curl, etc.) of the sheet caused when the sheet is separated or fed by the registration rollers. Also, the wrinkles are directed to the holding member side in a state where the wrinkles are alleviated, and the wrinkles are normally held, so that it is possible to prevent a flaw at the leading end of the sheet and to avoid a jam.

According to a third aspect of the present invention, there is provided a plate cylinder for winding a master formed on an outer peripheral surface, and an openable and closable holding member for holding a leading end of a conveyed sheet, so as to oppose the plate cylinder. In the printing apparatus having an impression cylinder to perform, the holding member has a stopper portion for abutting and positioning the leading end of the paper conveyed and conveyed, and a clamp portion for clamping the leading end of the paper, The joint between the stopper and the clamp is formed so that the leading end of the sheet abutting on the stopper is slid to a position deeper than the extended line of the stopper.

Therefore, when the leading end of the sheet is held by the holding member, the leading end of the sheet is abutted against the stopper portion.
After the leading edge of the sheet abuts against the stopper, the sheet moves to the clamp side. At this time, at the joint between the stopper and the clamp, the sheet slides to a position deeper than the extended line of the stopper. As a result, the leading end of the sheet is reliably located at the joint, and is securely clamped without bending.

According to a fourth aspect of the present invention, there is provided a plate cylinder for winding a master made on an outer peripheral surface, and an openable and closable holding member for holding a leading end of a conveyed sheet, so as to face the plate cylinder. In the printing apparatus having an impression cylinder to perform, the holding member has a stopper portion for abutting and positioning the leading end of the paper conveyed and conveyed, and a clamp portion for clamping the leading end of the paper, A pocket portion which is deeper than an extension line of the stopper portion is formed at a joint portion of the stopper portion with the clamp portion.

Therefore, when the leading end of the sheet is held by the holding member, the leading end of the sheet is abutted against the stopper portion.
After the leading edge of the paper strikes the stopper, it moves to the clamp side.In this case, at the joint between the stopper and the clamp, make sure that the paper enters the pocket deeper than the extension line of the stopper. As a result, since the paper is moved, the leading edge of the sheet is securely located at the joint portion, and is securely clamped without bending.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. In the above-described conventional example, the present embodiment, and the like, members, components, and the like having the same function, shape, and the like are denoted by the same reference numerals, and description thereof will be omitted as much as possible. In addition, in order to simplify the drawings and the description, members and components that do not need to be specifically described in the drawings are omitted as appropriate, even if the members and the components are to be shown in the drawings.

First, in a stencil printing apparatus having a plate cylinder and an impression cylinder as an example of a printing apparatus to which the present invention is applied, components not described in the conventional example will be supplementarily described.

As shown in FIG. 1, FIG. 12 to FIG. 14, etc., the plate cylinder 22 has a support cylinder having an ink-permeable porous structure and a mesh screen of a plurality of ink-permeable layers wound around the outer peripheral surface thereof. (Not shown), and is rotatably supported around the support shaft 22A. 1 through a drive system of the plate cylinder 22 including a main motor 29 so that the rotation speed can be changed corresponding to a plurality of printing speeds.
Is rotated clockwise. A master clamper 2 for holding the leading end of a master 23 having a plate made and perforated and formed by a plate making portion (not shown) on the outer peripheral surface of the plate cylinder 22.
4 are arranged. The master clamper 24 is opposed to a ferromagnetic stage (not shown) provided along a generatrix on the outer peripheral surface of the support cylinder, and has a master clamper shaft 24a.
, And is rotatably supported via a magnet. The magnet is attached to a surface facing the above-described stage. When the plate cylinder 22 occupies a predetermined rotation position, the master clamper 24 is opened and closed by transmitting a driving force by an opening / closing device (not shown).

As shown in FIG. 12, an ink supply device 45 is provided inside the plate cylinder 22. An ink roller 46 that rotates in synchronization with the plate cylinder 22 in the same direction and supplies ink to the inner peripheral surface of the plate cylinder 22;
A doctor roller 47 which is arranged in parallel with the ink roller 46 with a slight gap therebetween and forms an ink reservoir 48 with the ink roller 46, and a pipe-shaped support shaft 22A which supplies ink to the ink reservoir 48. I have it. The ink roller 46 and the doctor roller 47 are rotatably supported on the front and rear sides of the side plate fixed to the support shaft 22A. The ink supplied from the ink reservoir 48 to the outer peripheral surface of the ink roller 46 is supplied to the inner peripheral surface of the plate cylinder 22 because a slight gap is provided between the plate cylinder 22 and the outer peripheral surface of the ink roller 46. . The ink is pumped by an ink pump from an ink pack disposed at an appropriate position, and is supplied to a spindle 22.
The ink is supplied to the ink reservoir 48 through the supply hole A.

The drive system of the plate cylinder 22 is connected to the drive system of the impression cylinder 20, and the main motor 29 also serves as a drive unit for driving the impression cylinder 20 to rotate. The impression cylinder 20 is driven to rotate counterclockwise at a peripheral speed equal to the rotational peripheral speed of the plate cylinder 1 in FIG. Z)
The outer peripheral surface of the plate cylinder 22 is freely movable toward and away from the plate cylinder 22. The outer peripheral portion of the impression cylinder 20 is formed with a cylindrical portion that contacts the outer peripheral surface of the plate cylinder 22 and the above-described recess 21.

Hereinafter, an example of a stencil printing apparatus proposed in Japanese Patent Application Laid-Open No. 2000-238400 will be described with reference to FIGS. 1 to 7.

In FIG. 1, reference numeral 1 denotes Japanese Patent Laid-Open No. 2000-2
38 shows a paper holding device in an image printing apparatus disclosed in Japanese Patent No. 38400. The sheet holding device 1 is openable and closable to lock the leading end of the sheet P at the time of sheet feeding, instead of the sheet clamper 30 of the clamping device 28, as compared with the conventional clamping device 28 shown in FIGS. A paper clamper 2 as a holding member, and a paper ejection kick-up claw 10 as a floating member that floats the leading end of the paper P from the outer peripheral surface of the impression cylinder 20 when the paper clamper 2 is opened during paper ejection. And an opening / closing mechanism 19 for selectively opening and closing the paper clamper 2 and a paper ejection kick-up claw 10 instead of one clamping mechanism having the above-described cam in the clamping device 28. The main difference is that a levitation mechanism 27 for selectively performing a levitation operation is separately provided.

Further, the paper holding device 1 includes a clamping device 2
Compared with the configuration and operation of FIG. 8, the above configuration allows the paper clamper 2 to be driven independently by the paper clamper cam 8 and the paper ejection kick-up claws 10 by the kick-up pawl cam 17, respectively. The opening angle θ1 of the paper clamper 2 at the time of paper feeding shown in FIG.
(C) is set to be larger than the opening angle θ2 at the time of paper ejection, and the paper clamper 2 and the paper ejection kick-up claw 10 are driven substantially simultaneously at the time of paper ejection. The main difference is that the leading end 10e of the sheet P, which is biased to the upstream side in the sheet transport direction X from the free end of the sheet clamper 2 opened at the time of sheet ejection, floats.

The paper clamper 2 and the paper ejection kick-up claw 10 constitute a holding means for holding the leading end of the fed paper P. The locking member driving means for driving the paper clamper 2 mainly includes a main motor 29, a driving system of the impression cylinder 20, and the paper clamper cam 8. The floating member driving means for driving the ejection kicker 10 includes a main motor 29 and an impression cylinder 20.
And a lifter cam 17.

The opening / closing mechanism 19 is shown in FIGS. 1, 2, 3, and 5.
As shown in FIG. 6 and FIG.
A clamper cam follower 5 consisting of a roller which is always engaged with a paper clamper cam 8, a clamper arm 4 having the clamper cam follower 5 mounted on one end thereof with a shaft, and a predetermined angle of rotation on both side walls of the clamper base 6. The clamper arm 3 is movably supported, the other end of the clamper arm 4 is fixed via a screw, and the base end of the paper clamper 2 is fixedly attached thereto, and the base end is fixed to the clamper shaft 3. The paper clamper 2 is openable and closable so that its free end occupies three positions to be described later. The paper clamper 2 is urged so as to always open the paper clamper 2, and the clamper cam follower 5 is always pressed against the paper clamper cam 8. It is mainly composed of a torsion spring 7 for urging.

As shown in FIG. 1, the paper damper cam 8 is integrally formed of a suitable synthetic resin or metal, and is disposed near the outside of the end plate 20a of the impression cylinder 20 on the main body side of the stencil printing apparatus. It is provided fixed to a main body side plate (not shown). The paper damper cam 8 has a configuration and function as a locking member cam that converts the rotational movement of the impression cylinder 20 into the opening and closing operation of the paper damper 2 at a predetermined timing and transmits the same. The cam 8 for the paper clamper has a cam shape for opening and closing the paper clamper 2. That is, the paper clamper cam 8 engages with the clamper cam follower 5 provided on the paper clamper 2 side during paper feeding,
A small-diameter concave portion 8a for controlling the paper clamper 2 to open at the opening angle θ1 is located before the nip portion N and
It is formed at a predetermined position near the upstream side in the rotation direction of 0. Further, the paper clamper cam 8 engages with the clamper cam follower 5 when the paper is discharged, and
Small-diameter concave portion 8 for controlling the opening to open at the opening angle θ2
b is formed at a predetermined position near the downstream side in the rotation direction of the impression cylinder 20 after passing through the nip portion N. The cam 8 for the paper clamper except for the small-diameter concave portions 8a and 8b has the impression cylinder 2 attached thereto.
A uniform circumferential surface portion 8c formed with the same diameter around the zero impression cylinder shaft 26 is integrally formed.

The small diameter recess 8a of the paper clamp cam 8 is
In order to set the opening angle θ1 of the paper clamper 2 at the time of paper feeding to be larger than the opening angle θ2 at the time of paper discharging, the small diameter recess 8b is formed deeper than the depth of the recess. Due to such a relationship between the paper clamper 2 and the paper clamper cam 8 in the opening / closing mechanism 19, the paper clamper 2 is moved to the position shown in FIG.
And at the time of paper feeding shown in FIG.
The sheet P is opened at a minimum angle such that the leading end of the sheet P is released and freed at the opening angle θ2 when the sheet is discharged as shown in FIGS. 1 and 2C.

As shown in FIGS. 1, 2, 3 and 6, etc., the clamper base 6 has a substantially housing shape and is integrally formed of, for example, a synthetic resin or a metal such as aluminum. . A paper receiving surface 6a for receiving the leading end of the sheet P when clamping the leading end of the sheet P between the clamper base 6 and the clamp portion 2c of the sheet clamper 2 is provided above the upstream end of the clamper base 6 in the sheet conveying direction X. A plurality of escape portions 6b, which are cut out in a rectangular shape so as to occupy the leading end of the kick-up claw arm 12 at the paper floating position when paper is formed, are alternately formed in a comb-teeth shape in the paper width direction Y. As shown in FIG. 7, a spring hook 6 c for locking one end of the tension spring 16 is formed integrally with the bottom wall of the clamper base 6 so as to protrude downstream in the sheet conveying direction X. Clamper base 6
Each of the guided portions 10c protruding from both ends of the paper ejection kick-up claw 10 is loosely fitted into both side walls of the paper ejection kick-up claw 10.
In FIG. 7, kick-up claw guide windows 6d, 6d are formed to slidably guide in the sheet transport direction X. In the portion of the paper receiving surface 6a of the clamper base 6, there is no component for holding the paper claw 31 in the paper clamping state, such as the magnet 34 provided in the conventional clamping device 28, and the paper receiving surface 6a Clamp section 2 of paper clamper 2
c, the leading end of the sheet P is clamped.

The clamper arm 4 converts a part of the rotational driving force of the impression cylinder 20 and transmits the transmitted driving force to the clamper shaft 3 by engaging the paper clamper cam 8 and the clamper cam follower 5, ie, to the clamper shaft 3. This is a driving force transmitting member that transmits the sheet to the paper clamper 2.

The paper clamper 2 is formed of a thin stainless steel plate as an elastic member having a predetermined elasticity enough to absorb errors in accuracy of the paper clamper 2 itself and the paper clamper cam 8 and the like. The paper clamper 2 is made of, for example, a stainless steel plate having a thickness of 0.3 to 0.5 mm, and is formed in a crank shape so as to form a substantially Z-shape in cross section as shown in FIGS. It is bent and provided with the above-mentioned predetermined elasticity. The base end of the paper clamper 2 is fixed to a clamper shaft 3 via a screw (not shown). 2, 3, 5, and 6 are provided on the paper clamper 2.
As shown in FIG. 2, a stopper portion 2 for abutting the leading end of the sheet P fed from the pair of registration rollers 25a and 25b to determine its position and to form a predetermined flexure.
a, a notch 2b for avoiding interference of the leading end of the paper ejection kick-up claw 10 and allowing its movement, and 2-3 mm of the leading end of the paper P.
And a clamp portion 2c that clamps the portion are integrally formed.

As shown in FIGS. 3 (d) and 6, the clamp portion 2c of the paper clamper 2 is opened in the paper transport direction X at the free end of the conventional paper claw 31 shown in FIG. There is no comb-shaped relief 31a, and the free end of the paper clamper 2 is formed so as to extend substantially linearly in the paper width direction Y and has a predetermined width in the paper transport direction X. It has a shaped part. Therefore, even when the printing pressure is applied from the top end of the clamp portion 2c, which is the free end of the paper clamper 2, the printing pressure is not uniform on the portion of the plate-making master 23 on the plate cylinder 22 corresponding to this portion. The ink does not hang in the state, so that the ink does not accumulate.
Therefore, the plate cylinder 2 can be used without durable ink leakage.
The printing pressure can be applied immediately after the clamp mark to produce a print image, and the paper front margin length AL shown in FIG.
It has an advantage that it can be suppressed to a range of up to 5 mm.

As shown in FIG. 6, the torsion spring 7 is wound around the clamper shaft 3, and has one end on the back surface of the paper clamper 2 and the other end on the upper surface of the side wall on the front side of the clamper base 6. The sheet clamper 2 is always urged to open. The paper clamper 2 is set to have such a shape and dimensions as to generate an appropriate elastic restoring force when in a paper clamp state as shown in FIG. 2B. A predetermined range of necessary clamping force is generated between the paper clamper 2 and the paper receiving surface 6a by the predetermined elasticity of the paper clamper 2 itself and the cam shape of the uniform peripheral surface portion 8c of the paper clamper cam 8. I have. In other words, it can be said that the clamping and locking of the leading end of the sheet P by the sheet clamper 2 is performed based on the cam shape of the sheet clamper cam 8 and the predetermined elasticity. As described above, the paper clamper 2 is provided with a predetermined elasticity, and the paper clamper 2, the paper receiving surface 6a of the clamper base 6, and the paper clamper cam 8 are each formed in a relatively simple shape, so that the torsion spring is provided. 7 can be suppressed as small as possible, and it is not necessary to provide the magnet 34 on the base 35 as in the related art and to use the magnetic absorption force of the magnet 34.
There is also an advantage that the number of components can be reduced.

As described above, the sheet clamper 2 opens the sheet P at an opening angle θ1 to abut and clamp the leading end of the sheet P at the time of sheet feeding. The paper discharge position shown in FIG. 1 includes a paper clamp position (see FIG. 1) in which the paper P is clamped and closed, and a paper discharge position shown in FIG. It is configured to be displaceable between and can occupy three positions each.

FIGS. 1 to 4 and FIG.
As shown in FIG. 7, the above-described cam 17 for the kick-up pawl, a kick-up pawl cam follower 13 composed of rolling rollers which always engage with the cam 17 for the pick-up pawl, and a lift pawl cam follower 13
Arm 12 mounted on one end thereof with a shaft
And a riser claw shaft 11 rotatably supported on both side walls of the clamper base 6 by fixing the other end of the riser claw arm 12 via a screw, and a base end of the riser claw shaft 11. , The free end of which is in contact with the bent end 10b of the paper ejection kick-up claw 10 and is rotatable by a predetermined angle, and the above-mentioned kick-up claw guide windows 6d, 6d. A paper ejection rising claw 10 occupying a paper floating position for floating the front end of the paper P whose upstream end 10e is biased upstream in the paper transport direction X from the free end of the paper clamper 2 opened at the time of paper discharge; It is mainly composed of a tension spring 16 which urges the tip of the kick-up claw 10 from the floating position to a position occupying a non-floating position which is recessed inside the outer peripheral surface of the plate cylinder 22.

As shown in FIGS. 1 and 4, the kick-up pawl cam 17 is integrally formed of a suitable synthetic resin or metal, and is located near the impression cylinder 20, near the end plate 20a and the paper clamper cam 8. Are fixedly provided on the main body side plate. The kick-up pawl cam 17 has a configuration and function as a floating member cam for converting the counterclockwise rotational movement of the impression cylinder 20 into a floating operation of the discharge kick-up pawl 10 at a predetermined timing and transmitting the same. Cam 17 for kick nail
Is formed with a cam shape for driving the paper ejection kick-up claw 10 only at the time of paper ejection. That is, the cam 1 for the kick-up claw
Reference numeral 7 denotes a paper feeder which engages only with the riser cam follower 13 provided on the side of the paper discharge riser claw 10 at the time of paper discharge, and is higher than the free end of the paper clamper 2 opened at the time of paper discharge as described above. A mountain-shaped large-diameter convex portion 17a for controlling the leading end of the sheet P deviated to the upstream side in the direction X to be lifted up is formed. Cam 17 for kick nail
The large-diameter convex portion 17a is formed near the position where the small-diameter concave portion 8b of the paper damper cam 8 is disposed, near the upstream side in the rotation direction of the impression cylinder 20.

The rising claw arm 12 is provided with the rising claw cam 1.
7 and the riser claw cam follower 13 engage with the impression cylinder 2.
A driving force transmitting member that transmits the driving force that is converted by transmitting a part of the rotational driving force of 0 to the kick-up claw shaft 11, that is, to the discharge kick-up claw 10. 7, one of the lift-up pawl drive guides 14 is shown, but a plurality of lift-up pawl drive guides 14 are fixed to the lift-up pawl shaft 11 with screws in the same posture. Raising claw drive guide 14
Is the bent end 10b of the ejection kick-up claw 10.
, And is always in contact engagement with the urging force of the tension spring 16, and operates so as to move the entire paper ejection kick-up claw 10 by the rotation driving force transmitted from the kick-up claw cam follower 13 to the kick-up claw shaft 11.

The ejection kicker 10 is made of a thin stainless steel plate having a thickness of, for example, 0.8 to 1.0 mm. As shown in FIG. 2 and FIG. The leading end and the base end including the leading end 10e are lifted claw guide windows 6d, 6d via both guided portions 10c.
Are movable integrally within the range of formation. As shown in FIGS. 2, 3 and 7, etc., the paper ejection kick-up claw 10 has a plurality of notches 10a formed to avoid interference with the paper clamper 2 and the paper ejection claw 44 at the time of movement. The end portion 10b, the guided portions 10c, 10c, a spring hook portion 10d for locking the other end of the tension spring 16, and the tip end 10e are integrally formed. Paper ejection kick claw 1
The distal end portion including the zero distal end 10e is formed in a substantially comb-like shape so that the portion of each distal end 10e can be inserted into the escape portion 6b of the clamper base 6. The movement of the paper ejection kick-up claw 10 in the paper width direction Y is regulated by stoppers 18, 18 respectively fixed on the guided portions 10c, 10c with screws.

One end of the tension spring 16 is locked by the spring hook 6c of the clamper base 6, and the other end is
7, one of them is shown in FIG. 7, but the other is symmetrical with respect to the center of the ejection kick-up claw 10 in the sheet width direction Y. It is located at the location as described above. As described above, the ejection kick-up claw 10 is driven only by the above-described floating member driving means at the time of ejection, and is located upstream of the free end of the sheet clamper 2 opened at the time of ejection in the sheet transport direction X. The tip of the biased sheet P is caused to float, and is movable between a sheet floating position and a non-sheet floating position.

Next, the operation will be described. In this stencil printing apparatus, the transport operation of the paper P is performed with a specific feeding control. That is, a paper feeding means such as a paper feeding roller which is driven to rotate by a paper feeding motor (not shown) including a stepping motor (not shown) provided in the paper feeding unit is provided with an end plate 20 a of the impression cylinder 20.
The trigger of the paper feed motor is triggered by the point of engagement of the paper feed arm mounted on the side of the plate cylinder arm (not shown) that rotatably supports the paper supply light-shielding piece and the impression cylinder 20. Startup is controlled. Similarly, a pair of registration rollers 25a and 25b rotationally driven by a registration motor (not shown) formed of a stepping motor can rotate the resist light-shielding piece attached to the end plate 20a of the impression cylinder 20 and the impression cylinder 20 freely. The start of the registration motor is controlled by a trigger at the time of engagement with a transmission-type resist photosensor attached to a plate cylinder arm (not shown) supported by the printer. Since this feed control is not related to the present invention, further description is omitted.

In FIG. 1, the main motor 29
When the impression cylinder 20 rotates counterclockwise in FIG. 1 and the light-shielding sheet passes through the above-described sheet-feeding photosensor, the sheet-feeding motor is driven to rotate, whereby the sheet-feeding roller (not shown) of the sheet-feeding unit is driven. ), The double feeding of the sheet P is prevented, and one sheet P is fed. At this time, the clamper cam follower 5 of the impression cylinder 20
Is engaged with the uniform peripheral surface portion 8c of the paper clamper cam 8, so that the paper clamper 2 occupies the paper clamp position without clamping the leading end of the paper P. Further, at this time, since the kick-up pawl cam follower 13 of the impression cylinder 20 is not engaged with the kick-up pawl cam 17, as shown in FIG. 1 and FIG. 7 are held, and the ejection kick-up claw 10 occupies the non-sheet floating position by the urging force of each tension spring 16. On the other hand, when the leading edge of the fed sheet of paper P collides with the nip portion of the pair of registration rollers 25a and 25b, and is further conveyed by the sheet feeding motor, a predetermined amount of curved deflection is formed. Then, the rotation of the paper feed roller stops. Impression cylinder 2
1 further rotates counterclockwise in FIG. 1, and when the resist light-shielding piece passes through the above-described resist photosensor at a predetermined timing, the resist motor is driven to rotate.

The clamper cam follower 5 of the impression cylinder 20 is moved to the paper clamper cam
1 and FIG. 6, the clamper shaft 3 rotates counterclockwise together with the clamper arm 4 in FIGS. 1 and 6, thereby causing the paper clamper 2 to rotate in FIG. 1 and FIG. As shown in (a), the sheet is widely opened at the opening angle θ1, and the sheet clamper 2 occupies the sheet supply opening position. At this time, the paper clamper 2 is moved to the open angle θ1.
The biasing force of the torsion spring 7 acts in the opening direction.

The registration roller pair 25a, 25b is rotated by the rotation of the registration motor, so that the leading end of the sheet P is conveyed toward the stopper 2a of the sheet clamper 2 occupying the sheet supply opening position. It collides with 2a. In this manner, a predetermined curved deflection is formed at the leading end of the sheet P, as indicated by a virtual line in FIG.

When the impression cylinder 20 further rotates counterclockwise and the clamper cam follower 5 passes through the small-diameter concave portion 8a of the paper clamper cam 8 and engages with the uniform circumferential surface portion 8c at a predetermined timing, the clamper arm in FIG. 4, the clamper shaft 3 rotates clockwise against the urging force of the torsion spring 7, whereby the paper clamper 2 securely clamps the leading end of the paper P as shown in FIG. ,
The paper clamper 2 is closed. Thus, the paper clamper 2
Occupies the paper clamp position as shown in FIG.
The impression cylinder 20 rotates while holding the sheet P on the outer peripheral surface of the impression cylinder 20, and the leading end of the sheet P contacts the outer peripheral surface of the plate cylinder 22 with the impression cylinder 20.
Conveyed to the outer peripheral surface of the sheet.

A pair of left and right printing pressure springs (not shown) provided in the above-mentioned contacting / separating means is provided for the sheet P conveyed between the outer peripheral surface of the plate cylinder 22 and the outer peripheral surface of the impression cylinder 20. ), The nip portion N is formed by the upward rotation of the impression cylinder 20 pressing against the outer peripheral surface of the plate cylinder 22, and the outer peripheral surface of the impression cylinder 20 moves the sheet P to the outer peripheral surface of the plate cylinder 22. On the other hand, it is pressed via a master 23 (not shown in FIG. 1) which has been made. At this time, the printing pressure is applied from the top end of the clamp portion 2c, which is the free end portion of the paper clamper 2. However, even under such pressed state, the printing pressure is applied to the top end portion of the top surface of the clamp portion 2c for the reason described above. The printing pressure is not applied uniformly to the portion of the master plate 23 (not shown in FIG. 1) on the corresponding plate cylinder 22 so that the ink does not accumulate. A printing image can be obtained by applying the printing pressure to the plate cylinder 22 immediately after the clamp mark without causing leakage, and the length AL of the paper leading end margin shown in FIG. 12 can be suppressed to the range of 4 to 5 mm. .

In this way, the sheet P is continuously pressed by the master 23 wound around the outer peripheral surface of the rotating plate cylinder 22 by the pressing of the outer peripheral surface of the impression cylinder 20.
The prepressed master 23 comes into close contact with the outer peripheral surface of the plate cylinder 22, and ink leaks from the opening of the plate cylinder 22 to the perforated portion of the prepressed master 23, and is transferred to the surface of the sheet P, and the stencil printing is performed. Printing is performed. At this time, referring to FIG. 8, the ink roller 46 shown in FIG. 8 also rotates in the same direction as the rotation direction of the plate cylinder 22. The ink in the ink pool 48 is attached to the surface of the ink roller 46 by the rotation of the ink roller 46, and the ink roller 46 and the doctor roller 4 are rotated.
7 when passing through the gap between the plate cylinder 22 and the plate cylinder 22.
Is supplied to the inner peripheral surface.

When the impression cylinder 20 further rotates in the counterclockwise direction and reaches a position near the sheet discharge position before the sheet ejection claw 44, the impression cylinder 20
1 (c) and FIG. 4 of FIG. 1 when the kick-up pawl cam follower 13 starts engaging with the kick-up pawl cam 17.
As shown in FIG.
1 rotates counterclockwise against the urging force of each tension spring 16, whereby the lower free end of each kick-up pawl drive guide 14 moves the bent end 10 b of the paper discharge kick-up pawl 10 counterclockwise. Press while swinging in the direction. In this way, the tip 10e of the ejection kick-up claw 10 is
b, the ejection kicker 10 occupies the sheet floating position.

On the other hand, the opening operation of the paper clamper 2 is performed almost simultaneously with the operation of the paper ejecting claw 10 occupying the paper floating position. That is, when the impression cylinder 20 further rotates in the counterclockwise direction and reaches near the sheet discharge position before the sheet ejection claw 44, the clamper cam follower 5 of the impression cylinder 20 moves from the uniform circumferential surface portion 8 c of the sheet clamper cam 8 to the small-diameter concave portion. 8b at a predetermined timing, as shown in FIG.
4 and 6, the clamper shaft 3 rotates counterclockwise together with the clamper arm 4, thereby causing the paper clamper 2 to release the opening angle θ2 as shown in FIGS. 1 and 2C.
And the paper clamper 2 occupies the paper discharge position.

As described above, at the time of paper ejection, the paper clamper 2 and the paper ejection kick-up claw 10 operate almost simultaneously, and the tip 10e of the paper ejection kick-up claw 10 is opened at the time of paper ejection.
Occupying the sheet floating position for floating the leading end of the sheet P deviated to the upstream side in the sheet conveying direction X from the free end of the sheet P, makes it difficult to cause the ejection of paper to be wound up, and at the time of the lifting / raising operation as in the conventional apparatus. The leading end of the sheet P can be reliably lifted up without being detached from the leading end of the sheet P, and can be discharged toward the sheet discharge claw 44 and transferred, so that a jam or the like does not occur.

The printed paper P is peeled and guided by the paper discharge claw 44, and, when described with reference to FIG. 13, is conveyed by the paper discharge conveyance device 49 shown in FIG. 13 and is discharged and stacked on a paper discharge table (not shown). You. In this way, so-called plate printing, in which ink is filled in the master 23 having been made, is performed, and the plate cylinder 22 is separated from the impression cylinder 20 and returns to the initial state, and enters a printing standby state. After the printing is completed, the operator visually checks the discharged printed matter, checks the print image quality, checks the print image position, and the like. When these are OK, the paper feed, print, and discharge processes are set. This process is repeated for the number of prints, and the entire stencil printing process is completed.

FIG. 8 shows a characteristic configuration example of the present embodiment relating to the vicinity of the paper clamper 2 under a configuration example utilizing such a proposal example of JP-A-2000-238400.
This will be described with reference to FIG.

First, the stopper 2a of the paper clamper 2 will be described with reference to FIG. This stopper portion 2a
Is intermittently formed in the paper width direction as described above,
Although the leading end of the sheet P is partially received, in the present embodiment, the stopper 2a is disposed so as to be asymmetrical with respect to the center O in the sheet transport direction.
In this case, regardless of whether the stopper portion 2a itself is formed symmetrically or asymmetrically in the paper clamper 2,
In a use state in which the paper clamper 2 is attached to the shaft 3 of the clamper base 6, it suffices that the paper clamper 2 be asymmetrical with respect to the center O in the paper transport direction. As for the degree of asymmetry, as shown in the illustrated example, it is desirable that the stopper portions 2a be arranged in such a manner that the stopper portions 2a do not overlap at all when folded around the center O in the paper transport direction.

As a result, even when the same sheet P is passed twice while changing the front and back sides, as in the case of double-sided printing, for example, when the sheet P is clamped against the stopper 2a of the sheet clamper 2 Since the stopper portion 2a is disposed so as to be asymmetrical with respect to the center O in the paper transport direction, the same portion of the leading end that has hit the stopper portion 2a in the first sheet passing again hits the stopper portion 2a. Is eliminated, and the other portions strike, so that light scratches are sufficient and no noticeable tip scratches are caused by hitting twice.

Next, a pair of guide plates 40 and 41 located at the paper exit of the transport path toward the paper clamper 2 will be described with reference to FIG. These guide plates 40, 41
As shown in FIG. 14 and FIG. 1, generally, the guide plate is formed in parallel (see the broken line in FIG. 9), but in the present embodiment, the guide plate which is the upper guide plate By lowering the portion 40a on the leading end side (paper exit side) of the paper 40 so as to approach the guide plate 41 side and make it non-parallel, the upper surface of the paper P to be passed is always contacted and pressed to apply a load. It is configured. The portion 40a is formed of a flexible member separate from the guide plate 40 itself, but may be a hard member.

As a result, the registration rollers 25a, 25b
The sheet P conveyed toward the sheet clamper 2 is always subjected to a load due to a specific contact pressure by the portion 40a of the guide plate 40, and thus is squeezed. Therefore, sheet separation in the sheet feeding section and registration rollers 25a and 25b Even if there is a wrinkle (wave, curl, etc.) of the sheet generated during the feeding, the paper is directed toward the paper clamper 2 in a state where the wrinkle is alleviated due to the forced ironing at the portion 40a.
Therefore, the leading end of the sheet P is reliably inserted into the open sheet clamper 2 and is normally held, so that it is possible to prevent the leading end of the sheet P from being flawed due to a clamping error and to avoid a jam.

The lateral shape of the stopper 2a of the paper clamper 2 will be described with reference to FIGS. The angle θ between the stopper 2a and the clamp 2c in the paper clamper 2 is an acute angle, more preferably 8 °.
The angle is set to about 0 ° to 45 °. Further, a concave pocket portion 2e deeper than the extension line L of the stopper portion 2a is formed at a joint 2d of the stopper portion 2a with the clamp portion 2c.

Therefore, when the leading end of the sheet P is held by the sheet clamper 2, the leading end of the sheet P is
11A, the leading end of the sheet P strikes the stopper 2a as shown in FIG. 11A, and then moves toward the clamp 2c. At this time, the stopper 2a and the clamp 2c are aligned. The eye 2d slides and moves so as to enter the pocket portion 2e which is deeper than the extended line L of the stopper portion 2a. In other words, since the dimension d corresponding to the depth of the pocket portion 2e on the lower surface of the clamp portion 2c has a sliding effect in which the leading end of the paper P hitting the clamp portion 2c escapes farther than the joint 2d portion, the paper P FIG.
1 (b), the paper P bends in the opposite direction, and as a result, the leading edge of the paper P is reliably located at the joint 2d and is clamped by the clamp 2c. As shown in ()), the tip is securely clamped without being bent.

The stencil printing method described above is described as “paper P
And presses the impression cylinder 20 relatively to the plate cylinder 22 to perform printing on the paper P ", and presses the impression cylinder 20 against the plate cylinder 22 to perform printing. , Impression cylinder 20
There is a plate cylinder contact / separation method in which printing is performed by pressing the plate cylinder 22 against the plate cylinder, and a combined method thereof. Specific examples of the impression cylinder contact / separation method include the impression cylinder 20 and the contact / separation means in the above-described embodiment. On the other hand, as the plate cylinder contact / separation method, there is a well-known type in which the plate cylinder 22 moves toward the impression cylinder 20 (including a type in which the ink roller 46 inside the plate cylinder 22 projects toward the impression cylinder 20) to perform printing. No.

Further, the present embodiment has been described as an application example based on Japanese Patent Application Laid-Open No. 2000-238400 in which the kicking method is particularly improved. However, the present embodiment is applied to the conventional method as shown in FIGS. It is clear that it is still effective.

[0077]

According to the first aspect of the present invention, even when the same sheet is passed twice, as in the case of double-sided printing, etc., the sheet is clamped against the stopper of the holding member. Since the stopper portion is disposed asymmetrically with respect to the center in the sheet conveyance direction, the same portion of the leading end that abutted the stopper portion in the first sheet passing does not strike the stopper portion again. The scratches can be made inconspicuous.

According to the second aspect of the present invention, since the upper guide plate for applying a specific contact pressure to the upper surface of the sheet is provided at the sheet exit of the conveying path toward the holding member of the impression cylinder, the sheet facing the holding member is provided. Is wrinkled by a specific contact pressure from the upper guide plate, so that even if there are wrinkles (waves, curls, etc.) of the paper generated during paper separation or feeding by the registration rollers, the wrinkles were alleviated by the wrinkles. In this state, the sheet is directed toward the holding member, and is normally held. Thus, it is possible to prevent a flaw at the leading end of the sheet and to avoid a jam.

According to the third aspect of the present invention, the joint between the stopper and the clamp is formed so that the leading end of the sheet abutting on the stopper is slid to a position deeper than the extension line of the stopper. Therefore, when the leading edge of the paper abuts against the stopper portion when the leading edge of the paper is held by the holding member, the leading edge of the paper abuts against the stopper portion, and then moves toward the clamp portion. At the joint part with the clamp part, it slides to the position deeper than the extension line trajectory of the stopper part, so that the leading edge of the paper is securely located at the joint part, and the paper is securely clamped without bending Can be done.

According to the fourth aspect of the present invention, since the pocket portion which is deeper than the extended line of the stopper portion is formed at the joint portion of the stopper portion with the clamp portion, the leading end of the sheet is held by the holding member. When the leading edge of the sheet abuts against the stopper portion, the leading edge of the sheet abuts against the stopper portion and then moves toward the clamp portion. At this time, at the joint portion between the stopper portion and the clamp portion, the stopper portion is Since the paper is moved so as to enter into the pocket portion which is deeper than the extended line trajectory, as a result, the leading end of the sheet is securely located at the joint, and can be securely clamped without bending.

[Brief description of the drawings]

FIG. 1 is a front view of a main part showing a configuration and an operation of a sheet holding device in a stencil printing apparatus to which an embodiment of the present invention is applied;

FIGS. 2A and 2B are diagrams showing the operation of the main part of the paper holding device in FIG. 1 by changing the rotational position of the impression cylinder to the same state, and FIG.
Shows the operating state of the paper clamper and the paper ejection kick-up claw at the time of paper feeding, (b) shows the paper clamp state of the paper clamper,
(C) is an enlarged front sectional view showing the operation state of the paper clamper and the paper ejection kicker at the time of paper ejection.

3A is a diagram showing an operation state of a paper clamper and a paper ejection kicker, FIG. 3B is a diagram showing only a clamper base of FIG. 2A, and FIG. FIG. 2A is a diagram illustrating only the paper ejection kick-up claw, and FIG. 2D is a diagram illustrating only the paper clamper of FIG.

FIG. 4 is a front view of a main part showing an operation state of a paper clamper and a paper discharge kick-up claw when the paper holding device in FIG. 1 discharges paper.

FIG. 5 is a sectional view taken along line VV of the paper clamper.

FIG. 6 is a perspective view showing a structure of a main part around an opening / closing mechanism and a floating mechanism of the sheet holding device in FIG. 1;

FIG. 7 is a perspective view showing a structure of a main part around a floating mechanism of the sheet holding device in FIG. 1;

FIG. 8 is a side view showing an example of a characteristic paper clamper arrangement according to the embodiment of the present invention.

FIG. 9 is an enlarged front view showing the vicinity of another characteristic paper clamper according to the embodiment of the present invention.

FIG. 10 is an enlarged front view showing still another characteristic paper clamper according to the embodiment of the present invention.

FIG. 11 is an enlarged front view showing the sheet abutting operation.

FIG. 12 is a schematic front view showing a rotation position of a paper clamper and a paper conveyance operation accompanying a rotation operation of an impression cylinder in a conventional stencil printing apparatus.

FIG. 13 is a sectional front view showing a part of a main part around a plate cylinder and an impression cylinder of a conventional stencil printing apparatus.

FIG. 14 is a sectional front view showing a part of a main part around a plate cylinder and an impression cylinder of a conventional stencil printing machine.

FIG. 15 is an exploded perspective view showing a part of a main part around a plate cylinder and an impression cylinder in FIG.

FIG. 16 is a plan view for explaining a leading edge margin length of a printed sheet.

FIG. 17 is a schematic front view of a main part showing an operation at the time of paper feeding by a clamp device in a conventional stencil printing apparatus.

FIG. 18 is a schematic front view of a main part showing a sheet clamping operation by a sheet clamper of a conventional clamping device.

FIG. 19 is a schematic front view of a main part showing an operation at the time of printing pressure after paper clamping by a paper clamper of a conventional clamping device.

FIG. 20 is a schematic front view of a main part showing an initial operation of discharging a sheet when a sheet is clamped by a sheet clamper of a conventional clamp device.

FIG. 21 is a schematic front view of a main part showing an operation during sheet ejection by a sheet clamper of a conventional clamp device during sheet ejection.

FIG. 22 is a plan view of a sheet showing a front flaw caused by hitting a stopper claw.

FIG. 23 is a perspective view showing sheets in a stacked state at the time of double-sided printing in which a front end flaw has occurred.

FIG. 24 is a diagram for explaining occurrence of a bent tip in a clamping operation.

[Explanation of symbols]

 2 Holding member 2a Stopper portion 2c Clamp portion 2d Seam 2e Pocket portion 20 Impression cylinder 22 Plate cylinder 23 Master 40a Upper guide plate L Extension line locus O Center in paper transport direction P Paper

Claims (4)

[Claims] 1. A plate cylinder for winding a master made on an outer peripheral surface, and an impression cylinder having an openable and closable holding member for holding a leading end of a conveyed sheet and coming into contact with the plate cylinder. In the printing device, the holding member is formed intermittently in a sheet width direction, a stopper portion that abuts and positions a leading end of the sheet that is fed and conveyed, and a clamp portion that clamps the leading end of the sheet. Wherein the stopper portion is disposed asymmetrically with respect to the center in the sheet transport direction. 2. A plate cylinder for winding a master made on an outer peripheral surface, and an impression cylinder having an openable and closable holding member for holding a leading end of a conveyed sheet and coming in contact with the plate cylinder. In the printing apparatus, an upper guide plate for applying a specific contact pressure to the upper surface of the paper at an outlet of the paper in a conveyance path toward the holding member of the impression cylinder is provided. 3. A plate cylinder for winding a master made on an outer peripheral surface, and an impression cylinder having an openable and closable holding member for holding a leading end of a conveyed sheet and coming into contact with the plate cylinder. In the printing apparatus, the holding member has a stopper for abutting and positioning the leading end of the paper conveyed and conveyed, and a clamp for clamping the leading end of the paper, and the stopper and the clamp. A printing apparatus characterized in that a joint of the sheet and the leading end of the sheet abutting on the stopper is slid to a position deeper than a locus of an extension of the stopper. 4. A plate cylinder for winding a master made on an outer peripheral surface, and an impression cylinder having an openable and closable holding member for holding a leading end of a conveyed sheet and coming into contact with said plate cylinder. In the printing apparatus, the holding member has a stopper for abutting and positioning a leading end of the paper conveyed and conveyed, and a clamp for clamping the leading end of the paper, and a clamp for the stopper. A pocket portion which is deeper than an extension line of the stopper portion is formed at a joint portion of the printing device.