JP2756218B2 - Stencil printing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing machine for performing printing by winding a master perforated by a heating element such as a thermal head.

[0002]

2. Description of the Related Art A conventionally used master is a laminate obtained by laminating a thin thermoplastic resin film (about 2 to 8 μm thick) with a porous support made of Japanese paper, synthetic fibers, or a mixture of Japanese paper and synthetic fibers. It has a structure. The master film is heated and perforated by a heating element such as a thermal head, wound around a plate cylinder, supplied with ink from the inside of the plate cylinder, and pressed by a pressing member such as a press roller to form an opening in the plate cylinder and the master perforated. Printing is performed by exuding ink from the section and transferring it to printing paper. Since the ink passes through the fibers of the paper, such as Japanese paper, which is the porous support of the master, there are portions where the fibers are intertwined in a complicated manner (damaged portions), or the fibers traverse the perforated portions. In such a case, there is a problem that the permeation is hindered and a fibrous pattern appears on a solid portion, a thin line is cut or faded, that is, a so-called fibrous grain is generated.

[0003] Therefore, an attempt is made to reduce the problems caused by the fibrous grain by reducing the thickness of the porous support such as Japanese paper, which causes the generation of the fibrous grain, or by printing only with the thermoplastic resin film without using the porous support. Has been made. However, the apparent strength of the conventional master is borne by the porous support, and in the case of a thinner porous support or a master consisting of only a thermoplastic resin film, the strength of the master (lower ) Is greatly reduced.

A lock member for holding the leading end of the master is provided on the outer peripheral surface of the plate cylinder of the conventional stencil printing apparatus, and is composed of a stage portion parallel to the plate cylinder axis and a clamper member. Then, each time a new master is wound, the opening / closing member opens and closes the clamper member, and clamps the master tip.

In general, a master is transported to a locking member by a platen roller or a feed roller provided downstream of the master in the direction of transport of the master. Since the guide plate for guiding the master and the feed roller cannot be provided very close to the plate cylinder, there is no problem if the master has a stiffness like a master with a porous support. In a master having a thin body or a thermoplastic resin film alone, a slight waving phenomenon occurs due to shrinkage at the time of perforation, a habit of the film, or the like before reaching the locking member from the feed roller. If clamping is performed in this state, there is a problem that wrinkles are generated on the plate cylinder due to the undulation, resulting in poor printing. Therefore,
Japanese Patent Publication No. Sho 62-29 describes a technology in which the master is pressed onto the plate cylinder by wind pressure, and the master without a waist is clamped without generating wrinkles.
No. 97 is disclosed.

A substantially horizontal base paper support plate extending along the tangent plane of the top of the plate cylinder is provided in the vicinity of the plate cylinder, and the base paper support plate is formed of a rubber elastic body and has an edge on the base paper entry side. Attach an elastic member inclined from the center in the width direction toward both ends from the center in the width direction, clamp the base paper between the elastic member and the holding plate, pull the master when attaching the master to the plate cylinder, and wrinkle the master. Paper pulling device to take
No. -20297.

[0007] Further, at least two rollers rotatably provided at positions corresponding to both axial end regions of the plate cylinder,
An elastic member extending to a position closer to the plate cylinder than the roller, and a pressing member that contacts the roller and the elastic member, respectively, wherein the rollers are respectively arranged around axes inclined with respect to the axis of the plate cylinder. After the master is passed between the roller and the elastic member and the pressing member, the master is attached to the plate cylinder, and tension is applied to the master in a direction along the axial direction of the plate cylinder to allow the master to rotate. A base paper mounting apparatus for removing wrinkles is disclosed in Japanese Utility Model Publication No. 60-21243.

[0008]

[Problems to be solved by the invention]
The technique disclosed in Japanese Patent No. 2997 has a problem that the leading end of the master is unsteady at the time of blowing, and if it is clamped as it is, wrinkles are further promoted.

In the technique disclosed in Japanese Utility Model Publication No. 62-20297, the inclination of the edge is not effectively used to press the master with a flat surface.
The difference between the center and both ends causes variations in the pulling force of the master, causing wavy slack in the longitudinal direction of the master, which is the cause of the wrinkle and causes the master to wrinkle when winding the plate cylinder. There is a problem that it is. This is more noticeable as the master becomes thinner.

In the technique disclosed in Japanese Utility Model Publication No. Sho 60-21243, an elastic member for applying tension to the master and a roller are divided, and the arrangement distance from each plate cylinder is different. It is difficult to make the tension uniform, and a low-strength thin master has a problem in that a wavy slack occurs in the vertical direction due to a variation in tension, which causes wrinkles.

[0011]

According to the first aspect of the present invention,
A porous cylindrical rotatable plate cylinder, locking means provided on the outer peripheral surface of the plate cylinder for holding the tip of the master, and a thermal head for selectively heating and perforating the master according to image information A stencil printing machine comprising: a platen roller constituting a plate making means with the thermal head; and a conveying means for conveying the master around the outer peripheral surface of the plate cylinder. In the vicinity of the plate cylinder between the means and the plate cylinder, is provided so as to be accessible to the plate cylinder, and after the locking means clamps the tip of the master,
An extension member that contacts the master immediately before being wound around the plate cylinder, moves the contact portion in a direction approaching the plate cylinder, and applies tension to the master by the locking means. Features.

According to a second aspect of the present invention, in the stencil printing apparatus according to the first aspect, the extension member is further constituted by a rotatable roller.

According to a third aspect of the present invention, in the stencil printing machine according to the first aspect, the extension member further moves from a central portion thereof as a leading end portion in contact with the master advances in a conveying direction of the master. It is characterized in that it is inclined so as to expand toward each end.

[0014]

According to the first aspect of the present invention, at the time of winding the master around the plate cylinder, the extending member applies tension to the master from the direction in which the master is pressed against the plate cylinder.

According to the second aspect of the present invention, the frictional force between the extension member and the master is reduced.

According to the third aspect of the present invention, when the extension member applies tension to the master, both end portions of the master are moved outward.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 showing one embodiment of the present invention, a plate cylinder 1, which is driven to rotate clockwise by a motor (not shown), receives the leading end of a master in parallel with its own axis on its outer periphery. It has a stage 2. A clamper 3 provided in parallel with the stage 2 is pivotally mounted on the outer peripheral surface of the plate cylinder 1 by a shaft 4 and is rotatable by transmitting a driving force by an opening / closing member (not shown). Inside the plate cylinder 1, the plate cylinder 1
An ink roller 5 that rotates in synchronization with the roller and supplies ink to the plate cylinder 1 is provided so as to contact the inner peripheral surface of the plate cylinder, and the doctor roller 6 is formed in a wedge shape between the ink roller 5 and the doctor roller 6. Ink pool formed in space 7
Is uniformly supplied to the surface of the ink roller 5.
The ink is supplied to the ink reservoir 7 through an ink pipe 8 by an external ink supply device.

At the upper right of the plate cylinder 1, a master 9 made of a roll-shaped thermoplastic resin film is rotatably supported by a support shaft 10. In the vicinity of the master 9, a plate making means 70 including a platen roller 11 and a thermal head 12, which are driven to rotate counterclockwise by a stepping motor (not shown), is provided. A guide plate 13, a feed roller pair 14, and a bending guide plate 15 are arranged downstream of the platen roller 11 in the master transport direction, and form a master transport path.

Below the master transport path, link to the tip
A solenoid 16 having 17 is provided. Link 17
Is provided with a long hole 17a at the tip of the
23 is fitted and pin 23 is a substantially L-shaped drive arm
18 is fixed to one end. At the bent portion of the drive arm 18, a drive arm shaft 19 is provided integrally with the drive arm 18, and the drive arm shaft 19 is rotatably supported by a bearing (not shown) provided on the printing apparatus main body. . A pressure spring 22 composed of a tension spring is provided at an intermediate position between the pin 23 fixing position of the drive arm 18 and the insertion position of the drive arm shaft 19.
Is attached, and the other end is fixed to the link 17. As shown in FIG.
One end of an extension plate 21 for applying tension to the master 9 is attached to the distal end of the extension member 50, and the other end is attached to a driven arm 20 integrally attached to a drive arm shaft 19. Is composed. The width of the extension plate 21 is set to be larger than the width of the master 9.

The master 9 is subjected to plate making by being pressed against a platen roller 11 by a thermal head 12, guided by a guide plate 13, and then conveyed downward by a rotationally driven feed roller pair 14 and a bending guide plate 15. Reaches the vicinity of the outer peripheral surface of the plate cylinder 1. After the plate cylinder 1 rotates to position the locking means 60 composed of the stage section 2 and the clamper 3 at a predetermined position when the master is wound, the positioning stops. The clamper 3 rotates clockwise and separates from the stage unit 2, rotates to a predetermined angle, and stops.

The platen roller 11 and the feed roller pair 14 are rotated by a plate-making command, and the master 9 is conveyed while being heated and perforated by the thermal head 12 according to image information. When it is determined that it has reached the clamper 3, an opening / closing member (not shown) rotates the clamper 3, and clamps the leading end of the master 9 with the stage 2. At the same time when the clamper 3 is closed, the plate cylinder 1 also starts to rotate clockwise, and winding is started.

At the same time as the plate cylinder 1 starts rotating, the solenoid
16 is turned on, the linked link 17 is pulled, and the drive arm
18 is rotated clockwise about the drive arm shaft 19. Then, as shown in FIG. 2, the extension plate 21 rotates clockwise to bring its tip into line contact with the master 9, and the master 9 is wound around the plate cylinder 1 while removing wrinkles of the master 9. At this time, if the reaction force of the extension plate 21 exceeds the set value of the pressure spring 22, it overcomes the pressure spring 22 and rotates the drive arm 18 in the counterclockwise direction, so that excessive tension is not applied to the master 9. It has become.

When it is determined that the plate making is completed by reaching the set number of steps of the stepping motor (not shown), the heater wire 25 supported by the insulating holder 24 is energized, and the heater wire 25 is turned on. , And the insulating holder 24 and the heater wire 25 descend to melt the master 9. Platen roller 11 upon completion of fusing
Stops, the feed roller pair 14 stops after the master 9 has passed, the solenoid 16 is also turned off, the link 17 is returned by the return spring 26 composed of a compression spring, and the drive arm 18 contacts the stopper 27. Then, the prepress winding is completed.

After the winding is completed, the printing paper
29 is separated and fed by a paper feed roller 30 and a separation roller 31, guided by a paper guide plate 32, timed by a registration roller 33, and then inserted between a press roller 34 and the plate cylinder 1, and pressed. The master 9 is pressed by the roller 34 and comes into close contact with the plate cylinder 1 to complete printing.

In the above embodiment, the material of the extension plate 21 may be metal or resin, and the tip of the extension plate 21 that contacts the master 9 is
It is desirable to have a round shape so as not to damage the surface.

As shown in FIG. 4, the extension member 50 has a shaft 36 supported by the drive arm 18 and the driven arm 20, and has a roller 37 rotatable about the axis 36 instead of the extension plate 21. May be used.

As shown in FIG. 5, as the extension member 50, as the distal end portion 21a advances in the direction of transport of the master 9, the extension plates 21b are divergently inclined from the center to both ends. May be used in place of the extension plate 21.

As another embodiment of this embodiment, as shown in FIG. 6, a low friction resistance member 35 such as a fluororesin is smoothly coated or applied to the tip of the extension plate 21 to form a smooth surface layer. Alternatively, as shown in FIG. 7, a stretched plate 21c having a rounded end portion may be used, and a low frictional resistance member 35 may be smoothly coated or coated on the end portion. Good. Normally, a thin polyester film is used as the master 9, and an extension plate
If the frictional resistance is large when the contact is made, the perforated portion of the master 9 may be elongated or cut, resulting in an image defect.
When the extension plate 21 is configured as in the above-described embodiment, the frictional resistance at the time of contact with the master 9 is reduced, and the above-described problem can be solved.

As still another embodiment, as shown in FIG.
The fixing member 38 used in place of Shin-clad board 21, parts in contact with the master 9 by arranging the contact member 39, may be used that are linked to each other by an elastic member 40, the fixing member 3
8 shape, rather than limitations on the material, may be used any material as long as the material having a certain degree of rigidity. Abutment member 39, and the master 9 and which curved contact as shown in FIG. 8 as the shape, there are those such that line contact as shown by reference numeral 39 a in FIG. 9, as a material low friction A material equivalent to the resistance member 35 is preferable. The elastic member 40 is made of a material such as rubber or a leaf spring, and when the contact member 39 comes into contact with the master 9, a pressure is applied to the master 9 to such an extent that the master 9 is not deformed. In such a case, it is desired that the master 9 be elastically deformed and not apply excessive pressure to the master 9. With this configuration, the pressure spring 22 can be omitted, and the structure can be simplified.

In the above embodiment, if the surface of the heater wire 25 for fusing the master 9 is coated with a fluororesin or the like, the melted master adheres to the heater wire 25 when fusing and the cutting of the master becomes unstable. And the problem that irregularities are formed on the cut surface and transporting and nipping become unstable.

[0031]

According to the first aspect of the present invention, the extension member which can be approached to the plate cylinder at the time of winding the master around the plate cylinder after the locking means clamps the leading end of the master is provided. By contacting the master and moving the contact part in the direction of approaching the plate cylinder to apply tension to the master, the master is wound around the plate cylinder while eliminating the waving phenomenon that occurs on the master,
It is possible to prevent wrinkles from being generated on the master during winding on the plate cylinder.

According to the second aspect of the present invention, by using a roller as the stretching member, the frictional force between the stretching member and the master is reduced. The occurrence of wrinkles can be prevented.

According to the third aspect of the present invention, when the stretching member applies tension to the master, both side ends of the master move outward, so that wrinkles on the master when the plate cylinder is wound can be reduced. Can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a schematic side view of a main part of a stencil printing apparatus employing one embodiment of the present invention.

FIG. 3 is a partial perspective view illustrating an embodiment of the present invention.

FIG. 4 is a partial perspective view illustrating another embodiment of the present invention.

FIG. 5 is a partial perspective view illustrating another embodiment of the present invention.

FIG. 6 is a view showing a part of an extension member adopting another embodiment of the present invention.

FIG. 7 is a diagram showing a part of an extension member adopting another embodiment of the present invention.

FIG. 8 is a diagram showing a part of an extension member adopting another embodiment of the present invention.

FIG. 9 is a view showing a part of an extension member adopting another embodiment of the present invention.

[Explanation of symbols]

 1 Plate Cylinder 9 Master 11 Platen Roller 12 Thermal Head 21a Tip 37 Roller 50 Extension Member 60 Locking Means 70 Plate Making Means

Claims (3)

(57) [Claims] 1. A porous cylindrical and rotatable plate cylinder, locking means provided on an outer peripheral surface of the plate cylinder for holding a leading end of a master, and selectively selecting the master according to image information. A stencil printing machine, comprising: a thermal head that heats and perforates the plate; a platen roller that constitutes plate making means with the thermal head; and a conveying unit that conveys the master around the outer peripheral surface of the plate cylinder. In the vicinity of the plate cylinder between the locking means and the transport means, the plate cylinder is provided so as to be accessible to the plate cylinder, and after the locking means clamps the leading end of the master, it is wound around the plate cylinder. Stencil printing, comprising: an extension member that comes into contact with the master immediately before being mounted, moves the contact portion in a direction approaching the plate cylinder, and applies tension to the master by the locking means. apparatus. 2. The stencil printing apparatus according to claim 1, wherein said extending member is constituted by a rotatable roller. 3. The device according to claim 1, wherein the extension member is inclined in such a manner as to extend from a central portion to both ends as the tip portion in contact with the master advances in the conveying direction of the master. The stencil printing apparatus according to claim 1.