JP2002103768A - Printing equipment - Google Patents

Abstract

(57) [Problem] To prevent the formation of wavy deformation of a print medium when a print medium is conveyed by a belt from an upstream print section to a downstream print section, thereby preventing paper wrinkles. SOLUTION: Plate cylinders 40 and 50, and plate cylinders 40 and 50 are provided.
Printing units 4 and 5 having pressing rolls 46 and 56 for pressing
And a belt 62 disposed between the discharge side of the upstream printing unit 4 and the paper feeding side of the downstream printing unit 5 and the conveying surface side of the printing paper 45 of the belt 62 are sucked. An upstream belt transport mechanism 7 having a suction fan 64 is provided.
A conveyance guide member 78 having substantially the same height as the second conveyance surface is provided, and a large number of ribs 78a extending along the conveyance direction P1 are provided on the upper surface of the conveyance guide member 78.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus having a plurality of printing units for performing printing by pressing and transporting a printing medium between a plate cylinder on which a stencil sheet is mounted and a pressing rotary member pressing the plate cylinder. .

[0002]

2. Description of the Related Art Conventionally, various printing apparatuses having a plurality of printing units and capable of performing multicolor printing and double-sided printing have been proposed. FIG. 10 shows the overall schematic configuration of such a conventional stencil printing apparatus for double-sided printing. The figure is shown.

[0003] In FIG. 10, a stencil printing apparatus 100 includes:
Upstream and downstream stencils 104 and 105 for thermally perforating each stencil sheet 101 with thermal heads 102 and 103 based on respective image data, and the upstream stencil 1
The stencil sheet 101 made in step 04 is transferred to the plate cylinder 106 on the upstream side.
The printing paper 107 wound around and mounted on the printing cylinder 107 is fed to the plate cylinder 1.
06 and a pressing roll 108, an upstream printing unit 109 for transferring ink to the upper surface (one surface) of the printing paper 107 in the pressing and conveying process, and an upstream printing unit 109.
Feeder 110 that feeds print paper 107 to the printer, and upstream belt transport mechanism 11 that is disposed on the discharge side of print paper 107 of upstream print unit 109 and transports print paper 107 downstream.
1 and the stencil sheet 101 made by the downstream plate making section 105
Is wound around and mounted on the downstream printing drum 112, and the printing paper 107 fed by the upstream belt transport mechanism 111 is pressed and transported between the printing drum 112 and the pressing roll 114. In this pressing and transporting process, the printing paper 107 is And a downstream belt transport mechanism 117 that is disposed on the discharge side of the printing paper 107 of the downstream printing unit 115 and that transports the printing paper 107 to the downstream paper discharge tray 116.
And

The upstream and downstream belt transport mechanisms 111,
Reference numeral 117 denotes a belt that is hung between a plurality of belt hanging members 120 and has a plurality of small holes 121a (shown in FIG. 12), and a belt 121 for sucking the printing paper 105 transport surface side of the belt 121. It has a suction box 122 and a suction fan 123, and conveys the printing paper 107 by moving the belt 121 while sucking the printing paper 107 with the side opposite to the printing surface immediately before the printing paper 107 as a contact surface.

Next, the double-sided printing operation will be briefly described. Each of the plate cylinders 106 and 112 is rotated, and the printing paper 107 is fed from the sheet feeding unit 110 to the plate cylinder 106 on the upstream side in synchronization with the rotation. The fed printing paper 107 is pressed against the stencil sheet 101 of the printing drum 106 by a pressing roll 108 to transfer an ink image onto the upper surface of the printing paper 107. It is separated from the outer peripheral surface and guided to the upstream belt transport mechanism 111. The upstream belt transport mechanism 111 transports the printing paper 107 by moving the belt 121 with the lower surface of the printing paper 107 as a contact surface, and the plate cylinder 1 downstream from the most downstream of the belt 121.
12 is fed. The fed printing paper 107 is pressed against the stencil sheet 101 of the plate cylinder 112 by a pressing roll 114 to transfer an ink image to the lower surface of the printing paper 107.
And is guided to the downstream belt transport mechanism 117. The downstream-side belt transport mechanism 117 is provided for the printing paper 1
07 as the contact surface and the printing paper 107
1 and the discharge tray 1 from the most downstream of the belt 121.
It is discharged to 16. The printing paper 107 discharged to the discharge tray 116 is placed in a stacked state here.

[0006] A similar technique relating to the stencil printing apparatus 100 is disclosed in Japanese Patent Application Laid-Open No. Hei 8-90893.

Next, the configuration of the above-mentioned conventional upstream belt transport mechanism 111 will be described in detail. As shown in FIGS. 11 to 13, the plurality of belt hanging members 120 are provided with a straight shaft 12 arranged at a position close to the upstream plate cylinder 106.
0a, a shaft 120b with a pulley 130 disposed at a position close to the downstream plate cylinder 112, and these shafts 120b.
a, 120c and a shaft 120c with a pulley 130 disposed at a position close to the shaft 120a on the upstream side. The belt 121 includes a plurality of belts,
b and 120c are arranged in parallel at an interval by being hung on the position of the pulley 130. Each belt 121 is provided with a large number of small holes 121a, and also provided with a large number of small holes 122a at positions corresponding to the belt of the suction box 122. The suction force of the suction fan 123 is provided through these small holes 121a and 122a. It acts on the printing paper 107.

[0008]

However, in the conventional upstream belt transport mechanism 111, the suction box 1
The belt 12 protrudes from the upper surface 122 a of the belt 22.
1 is located, the portion where the belt 121 does not exist, including between the belt 121 and the belt 121,
1 is lower than the transfer surface. In particular, in the conventional example described above, the step becomes larger toward the downstream side of the conveyance, and there is a step at the most downstream by the height difference h of the pulley 130 with respect to the shaft 120b. When the printing paper 107 is conveyed on the belt 121 while receiving the suction force of the suction fan 123 in a state where there is such a step, as shown in FIG. Can be. That is, a wavy deformation occurs in the direction perpendicular to the transport direction of the printing paper 107. In particular, undulating paper such as thin paper is likely to have wavy deformation. If the paper is fed to the downstream plate cylinder 112 in a state where there is a wavy deformation, the paper may be pressed and conveyed in a state where the wave is not corrected. Will do.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and when a printing medium is conveyed from an upstream printing section to a downstream printing section by a belt, the printing medium is perpendicular to the conveyance direction. It is an object of the present invention to provide a printing apparatus capable of preventing the occurrence of a wavy deformation in the direction and preventing the occurrence of paper wrinkles.

[0010]

According to a first aspect of the present invention, there is provided a printing unit for performing printing by pressing and transporting a printing medium between a plate cylinder on which a stencil sheet is mounted and a pressing rotary member pressing the plate cylinder. A plurality of belts are provided between a paper discharge side of the upstream printing unit and a paper supply side of the downstream printing unit, and a suction fan that suctions the belt on the conveyance surface side of the printing medium. ,
In a printing apparatus provided with a belt transport mechanism that transports the print medium by moving the belt while sucking the print medium onto the belt, the belt transport mechanism may be configured such that a portion other than the belt is substantially flush with a transport surface of the belt. The present invention is characterized in that a step eliminating portion is provided.

In this printing apparatus, even when the print medium receives the suction force of the suction fan or the like, the portion of the print medium that does not contact the belt is not deformed by the step difference canceller.

According to a second aspect of the present invention, in the printing apparatus according to the first aspect, a plurality of the belts of the belt transport mechanism are arranged at intervals, and the step eliminating portion is provided at a location other than the belt. It is a transport guide member having a plurality of ribs arranged and extending along the transport direction of the print medium.

[0013] In this printing apparatus, in addition to the function of the first aspect, the print medium and the step elimination portion are in contact only through the rib.

According to a third aspect of the present invention, in the printing apparatus according to the second aspect, the step elimination portion is a belt hanging member on the most downstream side of the conveyance on which the belt is hanged, and It is characterized in that it is also provided at a place where the belt is not hung.

In this printing apparatus, claim 1 or claim 2
In addition to the effect of the invention, the print medium is prevented from being deformed in a wavy manner also at the position of the belt hanging member on the most downstream side.

According to a fourth aspect of the present invention, a plurality of printing units for performing printing by pressing and transporting a printing medium between a plate cylinder for mounting a stencil sheet and a pressing rotary member for pressing the plate cylinder are provided. A belt disposed between the paper discharge side of the printing unit and the paper supply side of the downstream printing unit, and a suction fan that suctions a side of the belt on which the printing medium is conveyed; and In a printing apparatus provided with a belt transport mechanism that transports the belt by moving the belt while sucking the belt, the belt of the belt transport mechanism is a wide belt having at least a full width in a direction orthogonal to a transport direction of the print medium. There is a feature.

In this printing apparatus, the belt is wide and the entire area of the printing medium is conveyed in a state of being placed on the belt, and the printing medium does not undergo wavy deformation in a direction perpendicular to the conveying direction.

The invention according to claim 5 is the printing apparatus according to claim 4, wherein the belt has a mesh structure over the entire area.

In this printing apparatus, in addition to the function of the fourth aspect of the present invention, the printing medium is sucked uniformly over the entire area of the belt.

According to a sixth aspect of the present invention, a plurality of printing units are provided for performing printing by pressing and conveying a printing medium between a plate cylinder for mounting a stencil sheet and a pressing rotating member for pressing the plate cylinder. A belt disposed between the paper discharge side of the printing unit and the paper supply side of the downstream printing unit, and a suction fan that suctions a side of the belt on which the printing medium is conveyed; and In a printing apparatus provided with a belt transport mechanism that transports the belt by moving the belt while sucking the belt, a transport surface of the belt is a curved surface that is curved in a transport direction of the print medium.

In this printing apparatus, the printing medium is conveyed in a shape curved in the conveying direction along the conveying surface of the belt, and has a shape that is very strong against deformation in the direction perpendicular to the conveying direction. Is not deformed in a wave-like manner even if the portion of the print medium positioned at the position receives the suction force of the suction fan.

According to a seventh aspect of the present invention, a plurality of printing units for performing printing by pressing and transporting a printing medium between a plate cylinder for mounting a stencil sheet and a pressing and rotating member for pressing the plate cylinder are provided. A belt disposed between the paper discharge side of the printing unit and the paper supply side of the downstream printing unit, and a suction fan that suctions a side of the belt on which the printing medium is conveyed; and In a printing apparatus provided with a belt transport mechanism that transports the belt by moving the belt while sucking the belt, the belt is curved in the transport direction of the print medium between a most downstream end of the belt transport mechanism and a downstream printing unit. A posture forcing guide member having a curved guide surface is provided.

In this printing apparatus, even if a portion of the printing medium other than the position of the belt is deformed into a wave shape by the suction force of the suction fan or the like, the wave-like deformation is conveyed by the posture correction guide member at the most downstream position. It is corrected from being curved and deformed in the direction.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show a first embodiment of the present invention. In the first embodiment, a case where the present invention is applied to a stencil printing apparatus (printing apparatus) capable of performing double-sided printing is shown.
FIG. 1 is an overall schematic configuration diagram of a stencil printing apparatus. FIG. 2A is an enlarged configuration diagram of main parts of two printing units, upstream and downstream, and an upstream belt conveying mechanism disposed therebetween. )
FIG. 2C is a plan view of the upstream belt transport mechanism, and FIG.
FIG. 3B is a cross-sectional view along the line AA, and FIG. 3 is a front view of the upstream belt transport mechanism.

As shown in FIG. 1, a digital stencil printing apparatus 1 includes a document reading unit (not shown), an upstream plate making unit 2 and a downstream plate making unit 3, an upstream printing unit 4 and a downstream printing unit 5 (not shown). , A paper feed unit 6, an upstream belt transport mechanism 7 and a downstream belt transport mechanism 8, a paper discharge unit 9, an upstream plate discharge unit 10, and a downstream plate discharge unit 11.

The document reading section has, for example, an automatic document feed reading section and a document placement reading section. The automatic document feed scanning unit
An obliquely inclined document plate on which the document is placed, a pair of document transport rolls for transporting the document placed on the document inclined plate, and a line image sensor that converts the content of the transported document into an electric signal and reads the signal. It is configured. This line image sensor is also used as that of the document placing and reading section.

The original placing / reading section includes a horizontal original placing glass table on which an original is placed, a pressure plate openably and closably provided on the original placing glass table, and a lower part of the original placing glass table. A guide belt that is moved by the driving force of the read pulse motor; and a line image sensor that is moved below the document placing glass table by the guide of the guide belt.

Then, the line image sensor reads the original conveyed by the original conveying rolls from the automatic original feeding and reading section. The document in the document placing and reading section moves by the line image sensor guided by the guide belt, and reads the document content.

The upstream-side stencil unit 2 includes a stencil container 21 for accommodating a rolled stencil sheet 20 and a writing head disposed downstream of the stencil sheet 20 in the transport direction of the stencil sheet 20. A thermal head 22, a platen roll 23 disposed at a position facing the thermal head 22, and rotated by a driving force of a not-shown write pulse motor, a platen roll 23 and the thermal head 22.
And a pair of stencil feed rolls 24, 24 disposed downstream of the stencil paper 20 in the transport direction of the stencil paper 20 and rotated by the driving force of the light pulse motor.
4 and a pair of stencil feed rolls 2 arranged further downstream
5, 25, and a base paper cutter 26 disposed downstream of the pair of base paper feed rolls 25, 25. The thermal head 22 has a plurality of dot heating elements arranged in a direction perpendicular to the direction of conveyance of the stencil sheet 20. In this embodiment, since the maximum printing paper is A3, the point heating elements extend over the range of A3 width. Is arranged.

Then, the stencil sheet 20 is conveyed by the rotation of the platen roll 23 and the stencil feed roll 24, and based on the image data corresponding to the upper surface (one surface) read by the line image sensor, each point heating element of the thermal head 22 is formed. Selectively heat-generates, heat-sensitive perforation is performed on the stencil sheet 20 to form a stencil, and a stencil cutter 26 cuts a downstream portion of the stencil sheet 20 to form a stencil sheet 20 having a predetermined length.

The downstream stencil unit 3 includes a stencil storage unit 31 for storing the rolled long stencil paper 20 and a writing head disposed downstream of the stencil storage unit 31 in the transport direction of the stencil paper 20. A platen roll 33 disposed at a position facing the thermal head 32 and rotated by a driving force of a write pulse motor;
A pair of stencil feed rolls 3 arranged downstream of the platen roll 33 and the thermal head 32 in the transport direction of the stencil sheet 20 and rotated by the driving force of a light pulse motor.
, 34 and a pair of base paper feed rolls 35, 35 arranged further downstream of the pair of base paper feed rolls 34, 34.
And a base paper cutter 36 disposed downstream of the pair of base paper feed rolls 35, 35. The thermal head 32 has a plurality of dot heating elements arranged in a direction perpendicular to the direction of conveyance of the stencil sheet 20. In this embodiment, since the maximum printing paper is A3, the point heating elements extend over the range of A3 width. Is arranged.

The stencil sheet 20 is conveyed by the rotation of the platen roll 33 and the stencil feed roll 34, and each point heating element of the thermal head 32 is read based on image data corresponding to the lower surface (the other surface) read by the line image sensor. Selectively heat-generates heat to form a stencil by heat-perforating the stencil 20 and cut the downstream portion of the stencil 20 by the stencil cutter 36 to produce the stencil 20 of a predetermined length.

The upstream printing section 4 has an outer peripheral portion made of an ink-permeable member having a porous structure. The upstream printing cylinder 40 is rotated in the direction of arrow A in FIG. 1 by the driving force of a main motor (not shown). A stencil sheet 20 is provided on the outer peripheral surface of the plate cylinder 40 and has a clamp portion 41 for clamping the leading end of the stencil sheet 20.

The upstream printing unit 4 includes a squeegee roll 42 and a doctor roll 43 arranged inside the plate cylinder 40, an ink supply unit 44 for supplying ink between the two rolls 42, 43, A pressing roller 46 as a pressing and rotating member for pressing a printing paper 45 as a printing medium conveyed in synchronization with the rotation of the printing drum 40 against the stencil sheet 20 of the printing drum 40, There is a pressing means (not shown) for moving to a pressing position for pressing the surface (solid line position in FIG. 1) and a separating position (virtual line position in FIG. 1) for separating from the outer peripheral surface of the plate cylinder 40.

Then, the leading end of the stencil sheet 20 conveyed from the upstream stencil unit 2 is clamped by the clamp unit 41, and the plate cylinder 40 is rotated in this clamped state, and the stencil sheet 20 is rotated.
Is wrapped around the outer peripheral surface of the plate cylinder 40, and the printing paper 45 conveyed in synchronization with the rotation of the plate cylinder 40 is pressed against the stencil sheet 20 of the plate cylinder 40 by the pressing rolls 46 to form the printing paper 45. The ink is transferred from the perforated portion of the stencil sheet 20 to the upper surface (one surface) to print an image.

The downstream printing section 5 has an outer peripheral portion formed of a porous ink-permeable member, and the downstream printing drum 5 is rotated in the direction of arrow B in FIG. 1 by the driving force of the main motor.
0, provided on the outer peripheral surface of the plate cylinder 50,
And a clamp part 51 for clamping the tip of the head.

The downstream printing section 5 includes a squeegee roll 52 and a doctor roll 53 disposed inside the plate cylinder 50, an ink supply section 54 for supplying ink between these two rolls 52 and 53, A pressing roller 56, which is a pressing and rotating member that presses the printing paper 45, which is a printing medium conveyed in synchronization with the rotation of the plate cylinder 50, onto the stencil sheet 20 of the plate cylinder 50; There is a pressing means (not shown) for moving to a pressing position (solid line position in FIG. 1) pressing against the surface and a separating position (virtual line position in FIG. 1) separating from the outer peripheral surface of the plate cylinder 50.

The leading end of the stencil sheet 20 conveyed from the downstream stencil unit 3 is clamped by a clamp unit 51. In this clamped state, the plate cylinder 50 is rotated to rotate the stencil sheet 20.
Is wrapped around the outer peripheral surface of the plate cylinder 50, and the printing paper 45 conveyed in synchronization with the rotation of the plate cylinder 50 is pressed against the stencil sheet 20 of the plate cylinder 50 by a pressing roll 56 to form the printing paper 45. The ink is transferred from the perforated portion of the stencil sheet 20 to the lower surface (the other surface) to print an image.

The paper feed unit 6 is a printing paper 45 serving as a printing medium.
And a primary paper feed roll 58 for moving only the uppermost printing paper 45 from the paper supply table 57
And a pair of secondary paper feed rolls 5 that convey the printing paper 45 moved by the primary paper feed roll 58 between the plate cylinder 40 and the pressing roller 46 in synchronization with the rotation of the plate cylinder 40 on the upstream side.
9, 59. The rotation of a main motor (both not shown) is selectively transmitted to the primary paper supply roll 58 and the secondary paper supply roller 59 via each paper supply clutch.

The upstream belt transport mechanism 7, which is a belt transport mechanism, receives the printing paper 45 discharged from the upstream printing unit 4, conveys the received printing paper 45 to a position before the downstream printing unit 5, and sends it to the downstream printing unit 5. The paper is fed to the side printing unit 5. The upstream side belt transport mechanism 7 includes three belt hanging members 60, 61, 76 arranged at intervals, a belt 62 wound between the plurality of belt hanging members 60, 61, 76, A suction box 63 and a suction fan 6 for sucking the transport surface side of the printing paper 45 of 62
4 and a belt driving means (not shown) for driving the belt 62 to rotate via the belt hanging member 76. The upstream belt transport mechanism 7 transports the printing paper 45 by its own movement while the belt 62 sucks the printing paper 45 with the contact surface on the side opposite to the immediately preceding printing surface of the printing paper 45.

The downstream belt transport mechanism 8 receives the printing paper 45 discharged from the downstream printing section 5 and transports the received printing paper 45 to the paper discharging section 9.
A pair of pulleys 66, 66 arranged at an interval, and a belt 67 hung between the pair of pulleys 66, 66
A suction box 68 and a suction fan 69 for sucking the transfer surface side of the printing paper 45 of the belt 67, and a belt driving means for rotating the belt 67 via the pulley 66. Then, the downstream belt transport mechanism 8
The belt 67 conveys the printing paper 45 by its own movement while sucking the printing paper 45 with the opposite side of the printing paper 45 from the immediately preceding printing surface as the contact surface.

The paper discharge section 9 has a paper discharge board 71 disposed at a position where the printed printing paper 45 conveyed by the downstream belt conveyance mechanism 8 is dropped. 45 are placed in a stacked state.

The leading end of the stencil sheet 20 wound around and mounted on the upstream plate cylinder 40 is released from the upstream stencil sheet 20.
A pair of stencil discharge rolls 72, 72 for transporting the stencil sheet 20 while being peeled off, and a pair of stencil discharge rolls 72, 7;
And a stencil discharge box 73 for accommodating the stencil sheet 20 conveyed by the stencil 2.

The leading end of the stencil sheet 20 wound around and mounted on the downstream plate cylinder 50 is released from the stencil sheet 20 on the downstream side.
A pair of stencil discharge rolls 74, 74 for transporting the stencil sheet 20 while being peeled off;
And a stencil discharge box 75 for accommodating the stencil sheet 20 conveyed by the stencil 4.

Next, the configuration of the upstream belt transport mechanism 7 will be described. As shown in FIGS. 2 (A) to 2 (C) and FIG. 3, the plurality of belt hanging members 60, 61, 76 are connected to the upstream plate cylinder 40.
A straight shaft 60a disposed at a position close to
Consisting of a substantially straight shaft 61a arranged at a position close to the downstream plate cylinder 50, and a shaft 76a with a pulley 77 arranged below the shafts 60a and 61a and near the upstream shaft 60a. Have been. The belt 62 is composed of a plurality of belts, and is arranged in parallel at intervals by being hung on the position of a pulley 77 on the shaft 76a. Each belt 62 is provided with a large number of small holes 62a, and a large number of small holes 63a are provided at positions corresponding to the belt of the suction box 63. The suction force of the suction fan 64 is provided through these small holes 62a and 63a. It acts on the printing paper 45.

The belt 6 is placed on the upper surface of the suction box 63.
At positions other than the belt 62, including between the belt 2 and the belt 62, there are provided conveyance guide members 78, each of which is a step eliminating portion. The transport guide member 78 is provided on its upper surface with a number of ribs 78a extending along the transport direction P1, and the upper surface height of the ribs 78a is set to be substantially the same as the transport surface of the belt 62. . Transport guide member 78
Is preferably made of a material having as little frictional resistance as possible. Further, the step eliminating portion is also provided at the position of the shaft 61a on the most downstream side of the conveyance where the belt 62 is hung, and in this embodiment, the portion where the belt 62 is hung is reduced to the small diameter portion 61b.
To the large diameter portion 61c
, The portion of the large diameter portion 61c, that is, the portion where the belt 62 is not hung, is set at the same height as the conveying surface of the belt 62. It is preferable that the large-diameter portion 61c of the shaft 61a is also made of a material having as little frictional resistance as possible.

Next, the stencil making and double-sided printing operations of the stencil printing apparatus 1 will be described. When the plate making operation is selected, each plate cylinder 4
It is checked whether or not the stencil sheet 20 is wound around 0, 50. If so, the stencil sheet 20 is removed from each of the plate cylinders 40, 50, and the stencil discharge boxes 73, 75 are mounted.
Discard each.

When the stencil discharging process is completed, the thermal head 22 pierces the stencil sheet 20 with the thermal head 22 based on the image data corresponding to the upper surface side read by the original reading operation. Then, a stencil printing process is performed in which the stencil sheet 20 having the stencil made is wound and mounted around the plate cylinder 40 on the upstream side, and the stencil making operation on the upstream side is completed. Further, the thermal head 32 performs thermal perforation on the stencil sheet 20 based on the read image data corresponding to the lower surface side. Then, a stencil printing process is performed in which the stencil sheet 20 having been stencil wound around and mounted on the downstream plate cylinder 50, and the stencil making operation on the downstream side is completed.

Next, when the printing operation is selected, the sheet feeder 5
It is checked whether or not there is a print sheet 45 on the print sheet 7, and if there is no print sheet 45, an out-of-paper error process is performed. Also, it is checked whether or not the stencil sheet 20 has been set on each of the plate cylinders 40 and 50, and if the stencil sheet 20 has not been set, a no-plate error process is performed. Also, it is checked whether or not there is ink in the ink pool between the squeegee rolls 42 and 52 and the doctor rolls 43 and 53, and if there is no ink, an error process for no ink is performed.

When all of these checks are passed,
Each of the plate cylinders 40 and 50 is rotated, and the printing paper 45 is fed from the paper feed unit 6 to the upstream plate cylinder 40 in synchronization with the rotation. The fed printing paper 45 is pressed against the stencil sheet 20 of the plate cylinder 40 by the pressing roll 46 to transfer the ink image onto the upper surface of the printing paper 45. It is separated from the outer peripheral surface and guided to the upstream belt transport mechanism 7. Upstream belt transport mechanism 7
The printing paper 45 is conveyed by the movement of the belt 62 with the lower surface of the printing paper 45 as a contact surface, and is fed to the plate cylinder 50 downstream of the lowermost stream of the belt 62. The fed printing paper 45 is pressed by the pressing roll 56 onto the stencil sheet 20 of the plate cylinder 50 via the belt 67, whereby the ink image is transferred to the lower surface of the printing paper 45, and the printing paper 45 printed on the lower surface is printed. Is separated from the outer peripheral surface of the plate cylinder 50 and guided to the downstream belt transport mechanism 8. The downstream belt transport mechanism 8 transfers the printing paper 45 to the belt 6 with the upper surface of the printing paper 45 as a contact surface.
7 and the discharge tray 71 from the lowermost stream of the belt 67.
Is discharged. The printing paper 45 discharged on the paper discharge table 71 is placed in a stacked state here.

The upstream belt transport mechanism 7 during the above operation process
In the transport operation of the printing paper 45 by the
Is attracted downward by the suction force of the suction fan 64 from the small holes 62 a of the belt 62, and the printing paper 45 contacts the belt 62 at a position where the belt 62 is present, and contacts the conveyance guide member 78 at a position where the belt 62 is not present. Conveyed while in contact. Therefore, as shown in FIG. 2C, even if a portion of the printing paper 45 that does not contact the belt 62 receives the suction force of the suction fan 64 or the like, the portion is not deformed by the conveyance guide member 78 in a wave shape. As described above, when the printing paper 45 is transported by the belt from the upstream printing unit 4 to the downstream printing unit 5, it is possible to prevent the printing paper 45 from being deformed in a wavy manner in the direction P2 orthogonal to the transport direction P1 and to prevent paper wrinkles. Can be prevented.

In the first embodiment, the transport guide member 7
8, a large number of ribs 78a extending along the transport direction P1 are provided, so that the printing paper 45 and the transport guide member 78 contact only through the rib 78a. Transport resistance can be reduced.

In the first embodiment, the portion of the belt hooking member 61a where the belt 62 is not hooked is the large diameter portion 61c with respect to the belt hooking member 61a on the most downstream side of the conveyance where the belt 62 is hooked. Therefore, it is possible to prevent the printing paper 45 from being deformed in a wavy shape even at the position of the belt hanging member 61a at the most downstream side.
It is possible to effectively prevent the occurrence of wavy deformation in the first orthogonal direction P2, and to more reliably prevent the occurrence of paper wrinkles.

4 to 6 show a second embodiment of the present invention. FIG. 4 is a plan view of the upstream belt transport mechanism, FIG. 5 is a front view of the upstream belt transport mechanism, and FIG. It is sectional drawing which follows the -B line. In the second embodiment, the first
The difference from the embodiment is that the upstream belt transport mechanism 7
Since only the configuration of A is the same and the other configuration is the same, the description of the same configuration will be omitted. Hereinafter, portions of the upstream transport mechanism 7A that are different from those of the first embodiment will be described.

In FIGS. 4 to 6, the belt 62A of the upstream belt transport mechanism 7A is configured as a single belt instead of a plurality of belts as in the first embodiment. The belt 62A has a width that is at least equal to the entire width of the printing paper 45 in the direction P2 orthogonal to the transport direction P1. Therefore, unlike the first embodiment, the transport guide member provided on the transport surface side of the belt other than the belt is not provided. In the second embodiment, the printing paper 45 that can be used is up to A3, so the belt 62
The width of A is set to be equal to or larger than the width of A3 paper. In the belt 62A, an area provided with a large number of small holes 62a and an area not provided with the small holes 62a are alternately arranged, and a suction box 63 corresponding to the area provided with the small holes 62a is provided.
Are provided with a large number of small holes 63a, and the suction force of the suction fan 64 acts on the printing paper 45 through the small holes 62a and 63a.

In the second embodiment, when the printing paper 45 is transported by the upstream belt transport mechanism 7A, the printing paper 45 is transported in a state where the belt 62A is wide and the entire area of the printing paper 45 is placed on the belt 62A. Therefore, even when the printing paper 45 is conveyed while being attracted downward by the suction force of the suction fan 64 or the like, the printing paper 45 does not undergo wavy deformation in the direction P2 orthogonal to the conveyance direction P1. Therefore, when the printing paper 45 is conveyed by belt from the upstream printing unit 4 to the downstream printing unit 5, the printing paper 45 is transported in the orthogonal direction P1 to the conveyance direction P1.
2 can be prevented from being deformed in a wavy manner, and the occurrence of paper wrinkles can be prevented.

In comparison between the second embodiment and the first embodiment, the second embodiment does not require the provision of a step elimination section (such as the transport guide member 78) as in the first embodiment.

FIG. 7 shows a third embodiment of the present invention.
FIG. 3 is a plan view of an upstream belt transport mechanism. The only difference between the third embodiment and the second embodiment is the configuration of the belt 62B of the upstream belt transport mechanism 7B.
That is, as shown in FIG. 7, the belt 62B according to the third embodiment is wide like the second embodiment, but has a mesh structure over the entire area. Further, the small holes 63a of the suction box 63 are also provided over the entire area. Since the other configuration of the upstream belt transport mechanism 7B is the same, the description of the same components will be omitted to avoid redundant description.

In the third embodiment, for the same reason as in the second embodiment, when the printing paper 45 is conveyed from the upstream printing unit 4 to the downstream printing unit 5 by a belt, the printing paper 45
In this way, it is possible to prevent the occurrence of paper-like wrinkles by preventing wave-like deformation in the direction P2 orthogonal to the transport direction P1. In addition, in the operation of transporting the printing paper 45, the printing paper 45 is suctioned uniformly over the entire area of the belt 62B, so that more stable transport is performed.

Comparing the third embodiment with the first embodiment, the third embodiment does not require the provision of a step eliminating portion (such as the transport guide member 78) as in the first embodiment.

FIG. 8 shows a fourth embodiment of the present invention.
FIG. 2 is an enlarged configuration diagram of two printing units, upstream and downstream, and a main part of an upstream belt transport mechanism disposed therebetween. The fourth embodiment differs from the first embodiment only in the configuration of the upstream belt transport mechanism 7C, and the other configurations are the same. Therefore, description of the same components will be omitted. I do. Hereinafter, portions of the upstream transport mechanism 7C that are different from those of the first embodiment will be described.

In FIG. 8, a plurality of belts 62C are arranged at intervals as in the first embodiment, but no transport guide member is provided at a position other than the belt 62C. Instead, the upper surface of the suction box 63 has a curved surface 7 that curves upward in the transport direction P1 of the printing paper 45.
9, so that the transport surface 80 of the belt 62C is curved in the transport direction P1 of the printing paper 45. Since the configuration of the other upstream belt transport mechanism 7C is the same as that of the first embodiment, the description is omitted to avoid redundant description.

In the fourth embodiment, when the printing paper 45 is transported by the upstream belt transport mechanism 7C, the printing paper 45 is transported along the transport surface 80 of the belt 62C in a curved shape in the transport direction. The orthogonal direction P of the transport direction P1
The belt 6 has a very strong waist shape against the deformation of the belt 2.
The position of the printing paper 45 where the 2C is not located is the suction fan 64
Does not deform wavy in the direction P2 orthogonal to the transport direction P1. Note that there is a possibility that the printing paper 45 is fed to the downstream printing unit 5 in a state where the printing paper 45 is curved in the conveyance direction P1. No paper wrinkles occur. As described above, when the printing paper 45 is transported by the belt from the upstream printing unit 4 to the downstream printing unit 5, it is possible to prevent the printing paper 45 from being deformed in a wavy manner in the direction P2 orthogonal to the transport direction P1 and to prevent paper wrinkles. Can be prevented.

In comparison between the fourth embodiment and the first embodiment, the fourth embodiment does not require the provision of a step elimination section (such as the transport guide member 78) as in the first embodiment.

In the fourth embodiment, the conveying surface of the belt 62C is formed as a curved surface curving upward, but may be formed as a curved surface curving downward. However, a curved surface that curves upward is easier to create.

FIG. 9 shows a fifth embodiment of the present invention.
FIG. 2 is an enlarged configuration diagram of two printing units, upstream and downstream, and a main part of an upstream belt transport mechanism disposed therebetween. The fifth embodiment differs from the first embodiment only in the configuration of the upstream belt transport mechanism 7D, and the other configurations are the same. Therefore, the description of the same components will be omitted. I do. Hereinafter, portions of the upstream transport mechanism 7D that are different from those of the first embodiment will be described.

In FIG. 9, a plurality of belts 62D are arranged at intervals as in the first embodiment, but no transport guide member is provided at a position other than the belt 62D. Instead, a posture forcing guide member 81 having a curved guide surface 81a curved downward in the transport direction P1 of the printing paper 45 is provided between the most downstream end of the belt transport mechanism 62D and the downstream printing section 5. Is provided. The other configuration of the belt transport mechanism 7D is the same as that of the first embodiment, and the description is omitted to avoid redundant description.

In the fifth embodiment, in the operation of transporting the printing paper 45 by the upstream belt transport mechanism 7D, the portion of the printing paper 45 where the belt 62D is not located receives the suction force of the suction fan 64 or the like to form a wave. Even if it is deformed, the wavy deformation is corrected because the printing paper 45 is curved and deformed in the transport direction P1 by the posture correction guide member 81 at the most downstream position.
As described in the fourth embodiment, the printing paper 45 may be fed to the downstream printing unit 5 in a state where the printing paper 45 is curved in the transport direction P1, but the printing paper 45 may be fed in the transport direction P1.
Even if the printing paper 107 is pressed and conveyed in a curved state, no wrinkles are generated on the printing paper 107. As described above, when the printing paper 45 is transported by the belt from the upstream printing unit 4 to the downstream printing unit 5, it is possible to prevent the printing paper 45 from being deformed in a wavy manner in the direction P2 orthogonal to the transport direction P1 and to prevent paper wrinkles. Can be prevented.

In the fifth embodiment, by adding a posture forcing guide member 81 to a conventional belt transport mechanism,
Paper wrinkles of the printing paper 45 can be prevented.

In the fifth embodiment, the curved guide surface 81a of the posture forcing guide member 81 is formed as a curved surface that curves downward. However, if the printing paper 45 can be forcibly conveyed along the curved surface. It may be formed as a curved surface that curves upward.

Further, according to the above embodiments, the case where the pressing and rotating member is constituted by the pressing rolls 46 and 56 has been described, but the pressing and rotating member reduces the printing pressure between the plate cylinders 40 and 50. Any member can be used as long as it can be applied, for example, plate cylinders 40 and 5
It may be a case in which it is constituted by an impression cylinder having substantially the same diameter as 0.

In the above embodiments, the plate cylinders 40, 50
A case has been shown in which the present invention is applied to a stencil printing machine 1 having two printing sections 4 and 5 of a printing roll and pressing rolls 46 and 56 as pressing rotating members. The present invention can be applied to a printing apparatus in which the transfer is performed by a belt transfer mechanism.

According to each of the above embodiments, the case where the present invention is applied to a stencil printing apparatus capable of performing double-sided printing has been described.
The present invention can be applied to a stencil printing machine having a plurality of printing units of a plate cylinder and a pressing and rotating member and capable of performing multicolor printing.

[0075]

As described above, according to the first aspect of the present invention, since the belt conveying mechanism is provided with the step eliminating portion for making the portion other than the belt substantially the same height as the belt conveying surface,
Even when the printing medium receives the suction force of the suction fan or the like, the portion of the printing medium that does not contact the belt is not deformed in a wave shape by the step eliminating portion. For this reason, when the printing medium is conveyed from the upstream printing section to the downstream printing section by a belt, it is possible to prevent the print medium from being deformed in a wavy shape in a direction orthogonal to the conveyance direction, thereby preventing the occurrence of paper wrinkles.

According to the second aspect of the present invention, since the printing medium and the step preventing portion contact only via the ribs, the conveyance resistance of the printing medium can be reduced.

According to the third aspect of the present invention, since the print medium is prevented from being deformed in a wavy manner even at the position of the belt hanging member at the most downstream side, the print medium can be deformed in a wavy manner in a direction orthogonal to the transport direction. Can be effectively prevented, and the occurrence of paper wrinkles can be more reliably prevented.

According to the fourth aspect of the present invention, since the belt of the belt transport mechanism has a width at least equal to the entire width in the direction orthogonal to the transport direction of the print medium, the belt is wide and the entire area of the print medium is the belt. The print medium is conveyed while being placed on the upper side, and the print medium does not undergo wavy deformation in a direction perpendicular to the conveyance direction. For this reason, when the printing medium is conveyed from the upstream printing section to the downstream printing section by a belt, it is possible to prevent the print medium from being deformed in a wavy shape in a direction orthogonal to the conveyance direction, thereby preventing the occurrence of paper wrinkles.

According to the fifth aspect of the present invention, since the printing medium is uniformly sucked over the entire area of the belt, more stable conveyance is performed.

According to the sixth aspect of the present invention, since the conveying surface of the belt is a curved surface curved in the conveying direction of the printing medium, the printing medium is curved in the conveying direction along the conveying surface of the belt. The printing medium has a very strong shape with respect to deformation in the direction perpendicular to the conveying direction, and does not deform in a wavy shape even when a portion of the printing medium other than the position of the belt receives the suction force of the suction fan or the like. For this reason, when the printing medium is conveyed from the upstream printing section to the downstream printing section by a belt, it is possible to prevent the print medium from being deformed in a wavy shape in a direction orthogonal to the conveyance direction, thereby preventing the occurrence of paper wrinkles.

According to the seventh aspect of the present invention, between the most downstream end of the belt transport mechanism and the downstream printing section, the posture forcing guide member having a curved guide surface curved in the transport direction of the print medium is provided. Even if a portion of the print medium other than the position of the belt is deformed in a wavy shape by receiving the suction force of the suction fan, the wavy deformation causes the print medium to bend in the transport direction by the posture correction guide member at the most downstream position. It is corrected from being done.
For this reason, when the printing medium is conveyed from the upstream printing section to the downstream printing section by a belt, it is possible to prevent the print medium from being deformed in a wavy shape in a direction orthogonal to the conveyance direction, thereby preventing the occurrence of paper wrinkles.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention and is a schematic configuration diagram of an entire stencil printing apparatus.

FIGS. 2A and 2B show a first embodiment of the present invention, in which FIG. 2A is an enlarged configuration diagram of two printing sections, upstream and downstream, and a main part of an upstream belt transport mechanism disposed therebetween; FIG. Is a plan view of the upstream side belt transport mechanism, and FIG.
It is sectional drawing which follows the A line.

FIG. 3 shows the first embodiment of the present invention, and is a front view of an upstream belt transport mechanism.

FIG. 4 is a plan view illustrating an upstream side belt transport mechanism according to a second embodiment of the present invention.

FIG. 5 shows a second embodiment of the present invention, and is a front view of an upstream belt transport mechanism.

6 shows a second embodiment of the present invention, and is a cross-sectional view taken along line BB of FIG.

FIG. 7 shows a third embodiment of the present invention, and is a plan view of an upstream belt transport mechanism.

FIG. 8 shows the fourth embodiment of the present invention, and is an enlarged configuration diagram of two printing sections, upstream and downstream, and a main part of an upstream belt transport mechanism disposed therebetween.

FIG. 9 shows the fifth embodiment of the present invention, and is an enlarged configuration diagram of two printing sections, upstream and downstream, and a main part of an upstream belt transport mechanism disposed therebetween.

FIG. 10 shows a conventional example, and is a schematic configuration diagram of the entire stencil printing apparatus.

FIG. 11 shows a conventional example, and is a cross-sectional view of an upstream belt transport mechanism.

FIG. 12 is a plan view of an upstream belt transport mechanism, showing a conventional example.

FIG. 13 is a front view of an upstream side belt transport mechanism, showing a conventional example.

14 shows a conventional example, and is a cross-sectional view taken along line CC of FIG.

[Explanation of symbols]

Reference Signs List 1 stencil printing device (printing device) 2 Upstream stencil making unit 3 Downstream stencil making unit 4 Upstream printing unit 5 Downstream printing unit 6 Feeding unit 7, 7A, 7B, 7C, 7D Upstream belt transport mechanism (belt transport mechanism) 8) downstream belt transport mechanism 9 paper discharge unit 10 upstream plate discharge unit 11 downstream plate making unit 20 stencil paper 40 upstream plate cylinder 45 print paper (print medium) 46 press roll (press rotating member) 50 downstream plate Body 56 Pressing roll (pressing rotating member) 60, 61, 76 Belt hanging member 62, 62A, 62B, 62C, 67 Belt 64 Suction fan 78 Transport guide member (step difference eliminating portion) 78a Rib P1 Transport direction P2 Direction perpendicular to the transport direction

Claims (7)

[Claims] A plurality of printing units for performing printing by pressing and transporting a printing medium between a plate cylinder on which a stencil sheet is mounted and a pressing rotary member for pressing the plate cylinder, and discharging the upstream printing unit. A belt disposed between the paper side and a paper supply side of the downstream printing unit, and a suction fan for suctioning the belt on the conveyance surface side of the printing medium, and sucking the printing medium onto the belt; In the printing apparatus provided with a belt transport mechanism that transports the belt by moving the belt, the belt transport mechanism is provided with a step eliminating unit that makes a portion other than the belt have substantially the same height as a transport surface of the belt. Printing device. 2. The printing apparatus according to claim 1, wherein a plurality of the belts of the belt transport mechanism are arranged at intervals, and the step eliminating unit is arranged at a location other than the belt. A printing apparatus comprising: a conveyance guide member having a plurality of ribs extending along a sheet conveyance direction. 3. The printing apparatus according to claim 2, wherein the step eliminating unit is a belt hanging member on the most downstream side of the conveyance on which the belt is hung, and the belt of the belt hung member is hung. A printing device characterized in that it is provided even in a place where it does not exist. 4. A printing unit for performing printing by pressing and transporting a printing medium between a plate cylinder on which a stencil sheet is mounted and a pressing rotating member pressing the plate cylinder, and discharging the upstream printing unit. A belt disposed between the paper side and a paper supply side of the downstream printing unit, and a suction fan for suctioning the belt on the conveyance surface side of the printing medium, and sucking the printing medium onto the belt; In the printing apparatus provided with a belt transport mechanism that transports the belt by moving the belt, the belt of the belt transport mechanism is wide at least having a total width in a direction orthogonal to a transport direction of the print medium. Printing device. 5. The printing apparatus according to claim 4, wherein the belt has a mesh structure over the entire area. 6. A plurality of printing units for performing printing by pressing and transporting a printing medium between a plate cylinder on which a stencil sheet is mounted and a pressing rotary member for pressing the plate cylinder, and discharging the upstream printing unit. A belt disposed between the paper side and a paper supply side of the downstream printing unit, and a suction fan for suctioning the belt on the conveyance surface side of the printing medium, and sucking the printing medium onto the belt; A printing apparatus provided with a belt transport mechanism that transports the belt by moving the belt, wherein a transport surface of the belt is a curved surface that is curved in a transport direction of the print medium. 7. A plurality of printing units for performing printing by pressing and conveying a printing medium between a plate cylinder for mounting a stencil sheet and a pressing rotary member for pressing the plate cylinder, and discharging the upstream printing unit. A belt disposed between the paper side and a paper supply side of the downstream printing unit, and a suction fan for suctioning the belt on the conveyance surface side of the printing medium, and sucking the printing medium onto the belt; In a printing apparatus provided with a belt transport mechanism that transports the belt by moving the belt, a curved guide surface curved between a most downstream end of the belt transport mechanism and a downstream printing unit with respect to a transport direction of the print medium. A printing device comprising a posture forcing guide member having