JP2003305933A - Stencil printing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stencil printing apparatus in which generation of erroneous detection of a paper detecting member caused by paper powder and the like can be decreased and efficiency of a printing operation can be prevented from being lowered. <P>SOLUTION: In the stencil printing apparatus 1 equipped with a printing part 2 provided with a plate cylinder 5 on which a master 21 is wound, and a paper feeding part 4 having a paper feeding roller 24 for feeding stored papers P and a resist roller 25, the paper detecting member 26 for detecting the papers P fed by the paper feeding roller 24 is provided at a position between the paper feeding roller 24 and the resist roller 25, and a cleaning member 27 for cleaning the paper detecting member 26 is provided by bringing it into slide contact with the paper detecting member 26. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing apparatus which obtains a printed matter by pressing a sheet against a master wound around a plate cylinder, and more specifically, a sheet feeding apparatus for feeding a sheet to a printing unit. Regarding the structure of the department.

[0002]

2. Description of the Related Art A rotatable plate cylinder formed by winding a plurality of layers of mesh screens of resin or metal mesh on a peripheral surface of a porous support plate which is a porous support cylinder, and a thermoplastic resin film (thickness). A thermoplastic resin film of a master using a master having a laminated structure in which Washi fibers or synthetic fibers or a mixture of Washi fibers and synthetic fibers are pasted together. A sheet that is heated and perforated by a thermal head or the like, and then wound around a plate cylinder and fed from a paper feed unit by a pressing unit such as a press roller while supplying ink from an ink supply unit provided inside the plate cylinder. Continuously pressing the master on the outer peripheral surface of the plate cylinder causes the ink to seep through the plate cylinder openings and master holes and transfer it to the paper. Digital stencil printing apparatus is generally known.

Since the paper feed section mounted on this stencil printing machine normally needs to favorably separate and feed a large number of papers stacked on the paper feed tray one by one, both have a high friction resistance. When a sheet of paper is pulled out from a paper feed tray by passing a sheet through the separating and feeding mechanism, which has a pair of rollers or a roller and a member having high frictional resistance. By using the fact that the frictional resistance between each sheet is smaller than the frictional resistance between the sheet and the roller or between the sheet and the member, it is possible to prevent the feeding of two or more sheets (hereinafter referred to as double feeding). There is.

[0004]

In the above-mentioned stencil printing machine, by pressing the sheet by the pressing means against the master which has been plate-formed on the outer peripheral surface of the plate cylinder, the plate cylinder opening portion and the master punching portion. Printing is performed by bleeding out more ink, and as the paper used for this stencil printing, inexpensive paper that is not suitable for offset printing, for example, waste paper made from the remaining lot of newspaper, etc. It also includes low-grade paper such as recycled paper, paper with a fluffy surface, and fibers that easily peel off.

Further, in the stencil printing machine, the position of the image printed on the paper in the paper transport direction is adjusted by changing the paper feed timing of the paper fed from the paper feed section. This timing change is performed by temporarily stopping the paper separated and fed from the paper feed tray and then changing the operation timing of the registration roller pair that is fed toward the printing unit at a predetermined timing, The operation timing of the registration roller pair is determined by a signal from the encoder for grasping the position of the plate cylinder in the rotation direction and the paper detection member (sensor) that detects that the paper is fed from the paper feed tray to the registration roller pair. It is controlled based on. The encoder is arranged near the plate cylinder, and the paper detection member is arranged downstream of the separation / feed mechanism in the paper conveyance direction.

As described above, in the stencil printing machine, since inexpensive papers that are not suitable for offset printing are used in some cases, if these papers are rubbed with a high friction resistance in the separating and feeding mechanism, the fibers or papers may be rubbed. Dust is easily generated, and the generated fibers and paper dust are easily attached to the surface of the paper detection member by the action of electrostatic force or the like. In particular, in a paper detection member having a resin cover or the like, the adhesion is remarkable due to the influence of electrostatic force or the like. For this reason, when printing a large amount using inexpensive paper, a large amount of fibers and paper dust generated from the paper adhere to the surface of the paper detection member, causing the paper detection member to erroneously detect and print normally. However, there is a possibility that the printing operation may be interrupted due to the detection of the remaining paper, the paper conveyance jam, and the like, even though the printing is performed.

Further, recently, the frequency of double-sided printing and multicolor printing has become high, and there is an increasing chance of re-passing paper with ink adhered on the front surface or the back surface. When a large amount of such paper is passed, peeling pieces or the like generated by peeling the ink attached to the paper or the dried ink may be attached to the paper detection member to cause the same problem as described above. There is. Further, the inexpensive paper that is not suitable for the offset printing described above has a difficult paper feed condition, and tends to cause a paper transport jam in the paper transport path. Since powder is likely to occur, problems caused by these are also likely to occur.

In order to prevent the occurrence of these problems, it is necessary to regularly clean the paper detection member, but the work is very troublesome and printing cannot be performed during cleaning. There is a problem in that the efficiency of is reduced. Also, depending on the device, it may be necessary to call a service person on the manufacturer side because the user cannot clean it.
In this case, the printing work must be stopped for several hours or days, which causes a problem that the efficiency of the printing work is extremely reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a stencil printing apparatus capable of preventing erroneous detection of a paper detection member due to paper dust or the like and preventing a reduction in efficiency of printing work. .

[0010]

The invention according to claim 1 is
A printing unit having a plate cylinder around which the master is wound, a paper feed roller for feeding the stored paper, and a registration roller for feeding the paper fed by the paper feed roller to the printing unit at a predetermined timing. In the stencil printing apparatus, the paper feed unit includes a paper detection member for detecting the paper fed by the paper feed roller at a position between the paper feed roller and the registration roller. And a cleaning member for slidingly contacting the paper detection member to clean the paper detection member.

According to a second aspect of the present invention, in the stencil printing apparatus according to the first aspect, the paper feed unit further includes a vertically movable paper feed tray on which the paper is stacked, and the paper detection member by the cleaning member. Cleaning is performed in conjunction with the raising / lowering operation of the paper feed tray.

According to a third aspect of the present invention, in the stencil printing apparatus according to the first aspect, the plate cylinder is detachable from the apparatus main body, and the cleaning of the sheet detecting member by the cleaning member is performed on the plate cylinder. It is characterized in that it is carried out in conjunction with the attaching / detaching operation of the apparatus main body.

According to a fourth aspect of the present invention, in the stencil printing apparatus according to the first aspect, there is further provided a cover that can be opened and closed with respect to the apparatus main body, and the cleaning of the sheet detection member by the cleaning member is performed by the cover. It is characterized in that it is performed in conjunction with the opening / closing operation with respect to the apparatus main body.

According to a fifth aspect of the present invention, in the stencil printing apparatus according to any one of the first to fourth aspects, the cleaning member moving further moves the cleaning member with respect to the paper detection member. It is characterized by having means.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic front view of the essential parts of a stencil printing machine adopting the first embodiment of the present invention. In the figure, the stencil printing apparatus 1 has a printing unit 2, a plate making unit 3, and a paper feeding unit 4.

The printing unit 2 is located substantially at the center of the apparatus main body (not shown) and is rotated by the plate cylinder driving means (not shown) in the direction of the arrow in FIG. The press roller 6 is provided so that it can come into contact with and separate from the press roller 6. An encoder is provided in the plate cylinder driving means (not shown) so that the position of the plate cylinder 5 in the rotation direction can be grasped.

The plate cylinder 5 has a porous support plate 5a whose both side edges are attached to respective peripheral surfaces of a pair of flanges (not shown), and a plurality of layers wound around the outer periphery of the porous support plate 5a (not shown). The porous support plate 5a is formed with an opening having a plurality of openings 5b. The plate cylinder 5 is attached to the non-opening portion of the porous support plate 5a.
A stage portion 7 that is a plane along one generatrix is provided, and a clamper 8 that is rotatably supported by a support shaft 8a is disposed on the stage portion 7. Clamper 8
Is opened and closed by an opening and closing means (not shown) when the plate cylinder 5 occupies a predetermined position.

Ink supply means 9 is arranged inside the plate cylinder 5. The ink supply means 9 has an ink supply pipe 10, which also serves as a spindle of the plate cylinder 5, an ink roller 11, a doctor roller 12, and the like. The ink supply pipe 10 is provided between a pair of flanges (not shown), and rotatably supports each flange via a bearing (not shown). An ink pump and an ink pack (not shown) are connected to the ink supply pipe 10, and the ink in the ink pack (not shown) is actuated by an ink pump (not shown) from the ink supply holes 10a provided in the ink supply pipe 10 to the plate cylinder. 5 is supplied inside.

The ink roller 11 is disposed between a pair of flanges (not shown) and is rotatably supported between a pair of side plates (not shown) fixed to the ink supply pipe 10, respectively. It is driven to rotate in the same direction in synchronization with the body 5. The ink roller 11 is arranged at a position where a slight gap is formed between the peripheral surface of the ink roller 11 and the inner peripheral surface of the plate cylinder 5.

A doctor roller 12 is arranged near the ink roller 11. The doctor roller 12 is also rotatably supported between the same side plates (not shown) as the ink roller 11, and is rotationally driven in the opposite direction in synchronization with the ink roller 11 by a rotational driving means (not shown). The doctor roller 12 is arranged at a position where a slight gap is created between the peripheral surface of the doctor roller 12 and the peripheral surface of the ink roller 11.

A space having a wedge-shaped cross section is formed in the vicinity of the ink roller 11 and the doctor roller 12, and an ink reservoir 13 is formed by accumulating the ink supplied from the ink supply hole 10a in this space. Ink fountain 1
The ink of No. 3 is the ink roller 11 and the doctor roller 12
It is supplied in a thin layer on the peripheral surface of the ink roller 11 when passing through the vicinity of the ink roller 11, and when the plate cylinder 5 is pressed by the press roller 6 described later, the peripheral surface of the ink roller 11 and the plate cylinder 5 are pressed.
It is supplied to the inner peripheral surface of the plate cylinder 5 by making contact with the inner peripheral surface of the plate cylinder 5.

A press roller 6 is arranged below the plate cylinder 5. It has almost the same length as the axial length of the plate cylinder 5,
The press roller 6 in which an elastic body such as rubber is wound around the core 6a is rotatably supported at both ends of the core 6a between one ends of a pair of press roller arms 14.
The pair of press roller arms 14, which are plate-shaped members, have their other ends fixed to a press roller shaft 15 rotatably supported by a device body (not shown), and are integrally formed by a press roller swinging device (not shown). Is oscillated. Due to this swinging, the press roller 6 separates its peripheral surface from the outer peripheral surface of the plate cylinder 5 as shown in FIG. 1, and the pressing position where the peripheral surface of the press roller 6 is pressed against the outer peripheral surface of the plate cylinder 5 with a predetermined pressing force. And occupy selectively.

A plate making section 3 is arranged on the upper right side of the printing section 2. The plate making unit 3 includes a master container member (not shown), a platen roller 16, a thermal head 17, a cutting means 18,
It has a master conveyance roller pair 19, a master guide plate 20, and the like.

Master storage members (not shown) are respectively provided on a pair of side plates (not shown) of the plate making section 3, and a master 21 formed by laminating a thermoplastic resin film and a porous support is wound into a roll. The core portion 21b of the roll 21a is rotatably and detachably supported.

A platen roller 16 is arranged to the left of the position where the master roll 21a is arranged. Platen roller 1
6 has an axial length substantially equal to the width of the master 21, and is rotatably supported between side plates (not shown) of the apparatus body. The platen roller 16 receives the driving force from the stepping motor 22 and is rotationally driven in the clockwise direction in FIG.

A thermal head 17 is arranged below the platen roller 16. The thermal head 17 is formed such that its width is larger than the axial length of the platen roller 16, and a plurality of heating elements are arranged on the upper surface thereof. The thermal head 17 is biased by a biasing means (not shown) so that the heating element surface is brought into pressure contact with the platen roller 16, and the operation of each heating element is individually controlled by a thermal head driver (not shown).

Platen roller 16 and thermal head 1
A cutting means 18 is arranged on the left side of the device 7. The cutting means 18 is fixed to an apparatus main body (not shown) and has a lower blade holder having a lower blade 18a whose width is formed larger than the width of the master 21, and is rotatable to move on the lower blade 18a in the width direction of the master 21. This is a well-known configuration including an upper blade holder having a large upper blade 18b.

A master conveying roller pair 19 is arranged on the left side of the cutting means 18. The master transport roller pair 19 is
Both have a driving roller 19a and a driven roller 19b which are rotatably supported between side plates (not shown). The driving roller 19a is driven to rotate by a master transport driving means (not shown) and the driven roller 19b pressed against the driving roller 19a. The master 21 is nipped and conveyed.

A master guide plate 20 for guiding the master 21 conveyed by the master conveying roller pair 19 to the plate cylinder 5 is arranged on the left side of the master conveying roller pair 19. The master guide plate 20 is fixed between side plates (not shown).

A sheet feeding section 4 is arranged on the lower right side of the plate cylinder 5. The paper feed unit 4 includes a paper feed tray 23, a paper feed roller 24,
It has a pair of registration rollers 25, a sheet detection sensor 26 as a sheet detection member, a cleaning member 27, and the like. The paper feed tray 23, on which a large amount of paper P is loaded, is supported by an apparatus body (not shown) so as to be able to move up and down, and is moved up and down by the operation of a tray elevating means (not shown).

A paper feed roller 24 is disposed above the paper feed tray 23 and at a portion corresponding to the leading end of the paper P in the conveying direction. The paper feed roller 24 formed by winding a high friction resistance member around the support shaft 24a is rotatably supported by the support shaft 24a via a bearing (not shown) between side plates (not shown) of the apparatus body, and is not shown. The urging means presses the uppermost sheet P on the sheet feed tray 23 with a predetermined pressing force.
The paper feed roller 24 is driven by a paper feed motor (not shown).
Is driven to rotate in the clockwise direction.

Below the paper feed roller 24, a paper separating member 28 made of a high frictional resistance member is arranged at a position downstream of the leading end of the paper P on the paper feed tray 23 in the paper carrying direction. It is set up. The sheet separating member 28 is pressed against the peripheral surface of the sheet feeding roller 24 with a predetermined pressing force.

The registration roller pair 2 is provided at a position downstream of the paper feed roller 24 and the paper separating member 28 in the paper carrying direction.
5 are provided. A registration roller pair 25 having a driving roller 25a and a driven roller 25b, both of which are rotatably supported between side plates (not shown) of the apparatus main body, includes a driving roller 25a which rotates by receiving a driving force transmitted from a registration driving means (not shown). The driven roller 25b pressed against the sheet P temporarily suspends the sheet P drawn from the sheet feed tray 23 by the sheet feed roller 24, and then feeds the sheet P between the plate cylinder 5 and the press roller 6 at a predetermined timing. To send.

A sheet guide plate 29 is provided between the sheet feeding roller 24 and the driving roller 25a, and a driven roller 25b is provided.
The paper guide plate 30 is provided at a position downstream of the paper conveyance direction.
Are arranged respectively. Each paper guide plate 29, 30
Are fixed between side plates (not shown) of the apparatus main body, and the paper guide plate 29 is provided with an opening (not shown) through which the detection light from the paper detection sensor 26 passes.

Between the paper feed roller 24 and the drive roller 25a, a portion located above the paper guide plate 29 is
A paper detection sensor 26 is provided. The paper detection sensor 26, which is a reflective sensor, has a light emitting portion and a light receiving portion on the surface facing the paper guide plate 29, and the light emitted from the light emitting portion is reflected by the paper P and returned to the light receiving portion. By this, it is detected that the paper P is fed by the paper feed roller 24.

In the vicinity of the lower part of the paper detection sensor 26, FIG.
As shown in FIG. 2, the brush portion 27a and the plate-like cleaning member main body 2
A cleaning member 27 having 7b is provided. The brush portion 27a, which is in sliding contact with the surface of the paper detection sensor 26 having the light emitting portion and the light receiving portion, is attached to one end of the cleaning member main body 27b, and the cleaning member main body 27b has substantially the same width as the paper detection sensor 26. ing. The cleaning member 27 is supported by a guide member (not shown) so as to be movable in the left-right direction in FIG. 2, and the other end thereof extends through the main body side plate 31 of the paper feeding unit 4 to the outside of the apparatus.

A cleaning member moving means 32 for moving the cleaning member 27 in the left-right direction in FIG. 2 is provided outside the apparatus on the main body side plate 31 and near the other end of the cleaning member main body 27b.
Is provided. The cleaning member moving means 32 includes a moving arm 33, a swing lever 34, a tension spring 35, and a stopper 3.
6, the projection 39 and the like.

The moving arm 33 is rotatably supported at its substantially central portion by a pin 38 provided on the body side plate 31 via a bracket 37. One end of the moving arm 33 is provided at the other end of the cleaning member body 27b. An engaging portion 33a that engages with a hole (not shown) is provided. One end of a swing lever 34 is attached to the other end of the moving arm 33 by a pin 34a. The swing lever 34 is attached to the moving arm 33 in such a manner that it can rotate in the clockwise direction and cannot rotate in the counterclockwise direction in FIG. 2, and the other end is attached to the body side plate 31. And extends to the inside of the device. Further, the other end of a tension spring 35 having one end fixed to the apparatus main body is attached near one end of the moving arm 33, and the moving arm by the biasing force of the tension spring 35 is near the other end of the moving arm 33. A stopper 36 for restricting the clockwise rotation of 33 around the pin 38 in FIG. 2 is provided. The stopper 36 is attached to the main body side plate 31 via a bracket (not shown).

A protrusion 39 for operating the cleaning member moving means 32 is provided at a portion of the main body side plate 31 inside the apparatus and corresponding to the other end of the swing lever 34.
The protrusion 39 is integrally attached to a rack member 40 that is integrally provided with the paper feed tray 23 and that moves up and down by meshing with a gear provided in a tray elevating means (not shown).

The operation of the stencil printing machine 1 in the first embodiment will be described below based on the above-mentioned configuration. When the plate making start key on the operation panel (not shown) is pressed after the document to be printed is set on the image reading unit (not shown),
A document image reading operation is performed in an image reading unit (not shown). The read image is stored in an image memory (not shown) as an image data signal. At the same time as the reading operation, the plate cylinder 5 starts to rotate, and a plate discharge unit (not shown) performs a plate discharge operation for separating the used master from the outer peripheral surface of the plate cylinder 5. The used master peeled off from the outer peripheral surface of the plate cylinder 5 is discarded in a plate discharge box (not shown) provided in the plate discharge section. When the plate discharge operation is completed, the plate cylinder 5 starts to rotate again, and the plate cylinder 5 stops at the plate supply standby position where the clamper 8 is located almost right beside. When the plate cylinder 5 stops at the plate supply standby position, the opening / closing means (not shown) is activated, the clamper 8 is opened, and the stencil printing apparatus 1 is in the plate supply standby state.

When the stencil printing machine 1 is in the plate feeding standby state,
Subsequently, the plate making operation is performed. When the clamper 8 is opened, the stepping motor 22 and a driving unit (not shown) are operated to rotate and drive the platen roller 16 and the driving roller 19a, and the master 21 is pulled out from the master roll 21a. Each of the heating elements of the thermal head 17 of the pulled-out master 21 generates heat based on the image data signal stored in the image memory, so that a plate-making image is formed on the surface of the thermoplastic resin film.

The master 21 is conveyed by the platen roller 16 and the master conveying roller pair 19 while being plate-formed by the thermal head 17, and is guided by the master guide plate 20 and sent to the opened clamper 8. When it is determined that the tip of the master 21 has reached a predetermined position where the master 21 is clamped by the clamper 8 based on the number of steps of the stepping motor 22, the opening / closing means (not shown) is actuated to close the clamper 8 and the outer periphery of the plate cylinder 5. The front end of the master 21 made on the surface is held.

After that, the plate cylinder 5 is rotationally driven in the clockwise direction in FIG. 1 at the same peripheral speed as the plate making and conveying speed of the master 21, so that the master 21 is wound around the plate cylinder 5. When it is determined from the number of steps of the stepping motor 22 that one plate has been completed, the platen roller 16
Also, the rotation of the master conveying roller pair 19 is stopped and the upper blade 18b is rotationally moved to cut the master 21. The cut master 21 is pulled out from the plate making unit 3 by the rotation of the plate cylinder 5, and when all the masters 21 are wound on the plate cylinder 5 and the plate cylinder 5 is stopped at the home position, the winding operation is completed.

In parallel with the above-described winding operation, the tray elevating means (not shown) is actuated to raise the paper feed tray 23 occupying the retreat position located below and to stack the paper on the paper feed tray 23. When the uppermost sheet P is brought into pressure contact with the paper feed roller 24 with a predetermined pressure contact force, the operation of the tray elevating means (not shown) is stopped. When the paper feed tray 23 is raised, the protrusion 39 attached to the rack member 40 that moves up together with the paper feed tray 23 abuts the swing lever 34. At the time of this abutment, the swing lever 34 moves the pin 34a. 2 is rotated in the clockwise direction about the
Do not move from the position shown in.

When the winding operation and the raising operation of the paper feed tray 23 are completed, the plate cylinder 5 is rotationally driven in the clockwise direction in FIG. 1 at a low speed, and the plate cylinder 5 is fed with a predetermined paper by the information from the encoder (not shown). When it is determined that the sheet has rotated to the feeding position, the sheet feeding motor (not shown) is activated and the sheet feeding roller 24
Is driven to rotate. By this rotation, the uppermost sheet P is pulled out from the sheet feed tray 23, and the pulled sheet P is separated in the sheet transport direction when passing between the sheet feed roller 24 and the sheet separating member 28. Separately fed paper P
Is fed toward the registration roller pair 25, and when the paper detection sensor 26 detects the paper P, it is determined that the leading edge of the paper P has reached the nip portion of the registration roller pair 25, and the operation of a paper feed motor (not shown) is activated. Is stopped.

Thereafter, based on information from an encoder (not shown), the registration roller pair 25 is set at a predetermined timing when the leading end of the image area of the master 21 which has been plate-formed on the plate cylinder 5 reaches a position corresponding to the press roller 6. The sheet P is fed between the plate cylinder 5 and the press roller 6 by being driven to rotate.

Almost at the same time as the rotation of the registration roller pair 25, the press roller oscillating means is operated to press the outer peripheral surface of the press roller 6 against the outer peripheral surface of the plate cylinder 5, and the paper P fed by the registration roller pair 25. Is pressed by the master 21 wound around the plate cylinder 5. Due to this pressing operation, the press roller 6, the sheet P, the master 21, and the plate cylinder 5 are brought into pressure contact with each other, and the ink supplied to the inner peripheral surface of the plate cylinder 5 by the ink roller 11 oozes out from the opening of the plate cylinder 5. After being filled in the porous support plate 5a, a mesh screen (not shown), and the porous support of the master 21, it is transferred to the paper P through the perforated portion of the master 21, and so-called plate making is performed.

The paper P on which the image is transferred by printing is
It is peeled from the outer peripheral surface of the plate cylinder 5 by a peeling member (not shown) arranged in the vicinity of the outer peripheral surface of the plate cylinder 5, and is conveyed by a paper discharge conveying member (not shown) arranged downstream of the plate cylinder 5 in the sheet conveying direction. Then, the sheet is discharged onto a sheet discharge tray (not shown). After that, the plate cylinder 5 is again rotated to the home position and stopped, and the stencil printing apparatus 1 is brought into a printing standby state after the plate mounting operation is completed.

After the printing operation is completed, the printing conditions are set, and then the test printing key on the operation panel (not shown) is pressed to perform the test printing. When the test printing key is pressed, the plate cylinder 5 is rotationally driven at the peripheral speed corresponding to the set printing speed, and the paper feed roller 24 is rotationally driven at the same timing as that at the time of printing. More paper P
Will be delivered. The fed paper P is separated in the paper conveyance direction when passing between the paper feed roller 24 and the paper separating member 28, and the leading end thereof is brought into contact with the nip portion of the registration roller pair 25. When the paper detection sensor 26 detects that the paper P is in contact with the registration roller pair 25, the rotation of the paper feed roller 24 is stopped.

The plate cylinder 5 continues to rotate during the above-described operation, and the registration roller pair 25 is rotationally driven at a predetermined timing similar to that at the time of printing, so that the plate cylinder 5 and the press roller 6 are separated from each other. The paper P is fed toward. The sheet P fed by the pair of registration rollers 25 is transferred to the image by being pressed against the outer peripheral surface of the plate cylinder 5 by the press roller 6. The sheet P after the image transfer is peeled off from the outer peripheral surface of the plate cylinder 5 by a peeling member (not shown), and is discharged onto a discharge tray (not shown) through a discharge conveying member (not shown) as in the case of printing.

When the image position, the image density, etc. are determined by the test printing, the operator presses the print start key (not shown) after setting these printing conditions and the number of prints, and the paper is fed from the paper feeding unit 4. P is continuously fed and printing is performed. This printing operation is performed in the same manner as the test printing operation. At the same timing as the test printing, a paper feed motor (not shown) is activated to rotationally drive the paper feed roller 24, and the paper P is fed to the paper feed roller 24 and the paper separating member 28.
The sheet is fed toward the registration roller pair 25 while being separated in the sheet conveying direction by. When the paper detection sensor 26 detects that the leading edge of the paper P is in contact with the registration roller pair 25, the rotation of the paper feed roller 24 is stopped.

After the rotation of the paper feed roller 24 is stopped, when the plate cylinder 5 is rotated to a predetermined position, the registration roller pair 25 is rotated to feed the paper P, and the fed paper P is pressed by the press roller 6 to the plate cylinder. The image is transferred by being pressed against the outer peripheral surface of 5. The sheet P to which the image is transferred is peeled from the outer peripheral surface of the plate cylinder 5 by a peeling member (not shown), and then discharged onto a paper discharge tray (not shown) via a paper discharge conveying member (not shown).

When the set number of prints is exhausted, the rotation of the plate cylinder 5 is stopped and the tray elevating means (not shown) is operated to occupy the paper feed position.
When 3 is lowered and the paper feed tray 23 occupies the retracted position, the operation of the tray elevating means (not shown) is stopped. When the paper feed tray 23 descends, the protrusion 39 attached to the rack member 40 that descends together with the paper feed tray 23 abuts the swing lever 34.

At the time of abutment with the projection 39, the swing lever 34 tries to rotate counterclockwise around the pin 34a, but rotation in the counterclockwise direction is restricted. As shown in FIG. 3, the swing lever 34 has a protrusion 39
You can get on. When the swing lever 34 rides up, the moving arm 33 rotates about the pin 38 in the counterclockwise direction in FIG. 2, and the cleaning member 27 moves leftward as shown in FIG. The brush portion 27 a provided on the sheet slides on the sheet detection sensor 26.

When the rack member 40 is further lowered, the projection 39 is lowered and the abutting state with the swing lever 34 is released, so that the movable arm 33 is pulled by the tension spring 35.
3 is rotated clockwise about the pin 38 by the urging force of the moving arm 33, and the moving arm 33 contacts the stopper 36 and returns to the initial state shown in FIG. At this time, the cleaning member 27 is moved to the right, and the brush portion 27a that was in contact with the sheet detection sensor 26 is returned to the initial position shown in FIG. 2 again.

By the reciprocating movement of the cleaning member 27 slidingly contacting the paper detection sensor 26, the fibers 27 and paper dust adhered to one surface of the paper detection sensor 26 are removed by the brush portion 27a, so that the paper detection sensor 26 is cleaned. As a result, the occurrence rate of erroneous detection of the paper detection sensor 26 is reduced.

In the above embodiment, the number of the protrusions 39 provided on the rack member 40 is one, and the cleaning member 27 for the paper detection sensor 26 when the paper feed tray 23 is lowered.
Although the example in which the number of reciprocating motions of the rack member is 1 is shown, the rack member 4
It is possible to make the cleaning member 27 reciprocate a plurality of times with respect to the sheet detection sensor 26 by providing a plurality of protrusions 39 on the sheet No. 0, thereby more reliably cleaning the sheet detection sensor 26 by the cleaning member 27. Is possible,
The occurrence rate of erroneous detection of the paper detection sensor 26 can be further reduced.

FIG. 4 shows a cleaning member moving means 41 used in the second embodiment of the present invention. The cleaning member moving means 41 is different from the cleaning member moving means 32 shown in the first embodiment only in that a solenoid 42 is used in place of the swing lever 34 and the protrusion 39, and the other parts. The configuration is the same.

With the above-described structure, the brush portion 27a which is in sliding contact with the sheet detection sensor 26 can be reciprocated by operating the solenoid 42 when the power is turned on or when the sheet is not fed, which is the same as in the first embodiment. The effect can be obtained. As a modification of the second embodiment, the cleaning member main body 27 is configured so that the brush portion 27a reciprocates like a piston of an internal combustion engine using a motor and a crank or the like.
A configuration in which a is extended to the outside of the apparatus body and the brass portion 27a is manually moved may be adopted.

FIG. 5 shows a third embodiment of the present invention. Compared with the first embodiment, this third embodiment has
In place of the plate cylinder 5, a plate cylinder 43 configured to be attachable to and detachable from an apparatus main body (not shown) is used, and the cleaning member moving means 3
The only difference is that the cleaning member moving means 44 is used instead of 2, and the other configurations are the same.

Like the plate cylinder 5, the plate cylinder 43 has a pair of flanges (not shown) and a porous support plate (not shown), and the plate cylinder 43 is shown on the outer end surface of one of the flanges. A shaft member 47 is integrally provided for fitting the positioning member 46 provided on the main body side plate 45 to position the plate cylinder 43 when it is mounted on the apparatus main body. Plate cylinder 43
Is provided with a handle (not shown), and by gripping the handle and pushing the plate cylinder 43 in the direction of the arrow in FIG. 5, the shaft member 47 is fitted to the positioning member 46 and the plate cylinder 43 is inserted.
Is attached to the apparatus main body (not shown), and the plate cylinder 43 is pulled out in the direction opposite to the arrow in FIG.

At a position on the rear side of the apparatus with respect to the main body side plate 45, and at a position corresponding to the position where the shaft member 47 is mounted,
A cleaning member moving means 44 is provided. The cleaning member moving means 44 has a moving arm 48, a tension spring 49, a stopper 50 and the like.

The moving arm 48 is rotatably supported by a pin 52 provided on the body side plate 45 via a bracket 51 near one end thereof, and at the other end by the cleaning member body 2.
An engaging portion 48a that engages with a hole (not shown) provided at the other end of 7b is provided. The disposing position of the moving arm 48 is located on the moving path of the shaft member 47 when the plate cylinder 43 is mounted on the apparatus body (not shown), and the shaft member 47 is fitted to the positioning member 46 to position the plate cylinder 43. It is set to a position where it can collide with the shaft member 47 when it is pressed.

To one end of the moving arm 48, the other end of a tension spring 49 having one end fixed to the main body of the apparatus is attached, and the moving arm 48 moves clockwise around the pin 52 in FIG. A rotational biasing force is applied. Near the other end of the moving arm 48, a stopper 50 that restricts the rotation of the moving arm 48 by the urging force of the tension spring 49 is provided. The stopper 50 is attached to the main body side plate 45 via a bracket (not shown).

With the above-described structure, when the plate cylinder 43 is mounted on the apparatus main body (not shown), the sheet detection sensor 26 is mediated by the moving arm 48 that abuts the shaft member 47 and rotates counterclockwise in FIG. The brush portion 27a can be brought into sliding contact with the one surface, and the same effect as that of the first embodiment can be obtained. According to this configuration, when the plate cylinder 43 is attached or detached when cleaning the inside of the apparatus main body, or when the plate cylinders 43 of different colors are attached and printing is performed, the paper detection sensor 26
Can be cleaned.

FIG. 6 shows a fourth embodiment of the present invention. Compared to the first embodiment, this fourth embodiment has
The other configurations are the same, except that the cleaning member main body 27c is used instead of the cleaning member main body 27b, and the cleaning member moving means 53 is used instead of the cleaning member moving means 32.

The plate-shaped cleaning member main body 27c has substantially the same width as the cleaning member main body 27b, and the other end facing the one end to which the brush portion 27a is attached is bent upward. A tension spring 54 is stretched between the other end of the cleaning member main body 27c and the main body side plate 31. Further, near the other end of the cleaning member main body 27c, a hole portion (not shown) for fitting the engaging portion 33a of the moving arm 33 is provided.

A cleaning member moving means 53 is provided outside the apparatus on the main body side plate 31 and near the other end of the cleaning member main body 27c. The cleaning member moving means 53 is a tension spring 5.
4, the moving arm 33, the main body cover 55 and the like.

The main body cover 55 is arranged on the front or side of the main body of the apparatus (not shown), and when the plate cylinder is replaced, the jammed paper is taken out, the plate discharge box is taken out, the paper is replenished, the inside of the apparatus main body is cleaned, etc. It is opened and closed. The body cover 55 is rotatably supported at its base end by a support shaft 56 provided on the apparatus body (not shown). The disposing position of the moving arm 33 is located on the moving path of the main body cover 55 at the time of opening and closing, and is set to a position where it can collide with the main body cover 55 when the main body cover 55 is closed.

With the above-mentioned structure, when closing the main body cover 55 with respect to the apparatus main body (not shown), the main body cover 55
The brush portion 2 is attached to one surface of the paper detection sensor 26 via a moving arm 33 that rotates in a clockwise direction in FIG.
7a can be brought into sliding contact with each other, and the same effect as that of the first embodiment can be obtained. According to this configuration, the paper detection sensor 26 can be cleaned when the above-mentioned main body cover 55 is opened and closed.

In each of the above embodiments, the cleaning member moving means 3
Although the brush portion 27a is slid with respect to the fixed sheet detection sensor 26 by 2, 41, 44 and 53, the brush portion 27a may be fixed and the sheet detection sensor 26 may be slid.

[0072]

According to the present invention, the cleaning member for slidingly contacting the paper detection member to clean the paper detection member is used for raising and lowering the paper feed tray.
Since the paper detection member is cleaned in conjunction with the operation of attaching / detaching the plate cylinder to / from the main body of the device and the opening / closing operation of the cover to the main body of the device, the cleaning member removes the fibers and paper dust attached to one surface of the paper detection member. As a result, the paper detection member is cleaned, and the occurrence rate of erroneous detection of the paper detection member is reduced, so that it is possible to prevent a reduction in the efficiency of printing work.

[Brief description of drawings]

FIG. 1 is a schematic front view of a main portion of a stencil printing apparatus adopting a first embodiment of the present invention.

FIG. 2 is a schematic view illustrating a cleaning member and a cleaning member moving means used in the first embodiment of the present invention.

FIG. 3 is a schematic view illustrating a cleaning member and a cleaning member moving means used in the first embodiment of the present invention.

FIG. 4 is a schematic view illustrating a cleaning member and a cleaning member moving means used in the second embodiment of the present invention.

FIG. 5 is a cleaning member used in the third embodiment of the present invention,
It is a schematic diagram explaining a cleaning member moving means and a plate cylinder.

FIG. 6 is a cleaning member used in a fourth embodiment of the present invention,
It is a schematic diagram explaining a cleaning member moving means and a body cover.

[Explanation of symbols]

1 Stencil printer 2 Printing department 4 Paper feeder 5,43 plate cylinder 21 Master 23 Paper tray 24 paper feed rollers 25 Registration roller pair 26 Paper detection member (paper detection sensor) 27 Cleaning member 32, 41, 44, 53 Cleaning member moving means 55 Body cover P paper

Claims (5)

[Claims] 1. A printing unit having a plate cylinder around which a master is wound,
In a stencil printing apparatus comprising: a paper feed roller for feeding the stored paper and a paper feed unit having a registration roller for feeding the paper fed by the paper feed roller to the printing unit at a predetermined timing, The paper feed unit has a paper detection member for detecting the paper fed by the paper feed roller at a position between the paper feed roller and the registration roller, and is in sliding contact with the paper detection member. A stencil printing machine having a cleaning member for cleaning the detection member. 2. The paper feed unit has a paper feed tray that can move up and down for stacking the paper, and the cleaning of the paper detection member by the cleaning member is performed in conjunction with the lifting operation of the paper feed tray. The stencil printing machine according to claim 1, wherein 3. The plate cylinder is attachable to and detachable from the apparatus main body, and the cleaning of the sheet detection member by the cleaning member is performed in conjunction with the operation of attaching and detaching the plate cylinder to the apparatus main body. The stencil printing machine according to claim 1. 4. A cover which can be opened and closed with respect to an apparatus main body, wherein cleaning of the sheet detection member by the cleaning member is performed in conjunction with opening and closing operation of the cover with respect to the apparatus main body. Item 1. The stencil printing apparatus according to item 1. 5. The stencil printing machine according to claim 1, further comprising a cleaning member moving unit that moves the cleaning member with respect to the paper detection member.