JP2005066900A - Stencil process printing device and printing paper conveying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent paper from being fouled by ink retransfer of a conveying member or the like under a simple structure in a stencil printing device and a printing paper conveying device. <P>SOLUTION: The stencil process printing device comprises a rotatable plate cylinder 39 to which a stencil is fitted: an ink supply mechanism for supplying an ink to the plate cylinder 39; and pressurizing rollers 40 and 42 for transferring the ink to printing paper by nipping the printing paper between the pressurizing roller 42 and the plate cylinder 39 and conveying the same. In the neighborhood of an imaging part formed between the plate cylinder 39 and the pressurizing roller 42, a timing roller 35 for nipping/feeding the printing paper to the imaging part by driving in synchronization with drive timing of the plate cylinder 39 and a guide roller 37, are arranged opposite to each other. The timing roller 35 has an outer peripheral layer consisting of a fine particle or an outer peripheral layer consisting of an ink repellent solid material formed on the roller 35. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a stencil printing apparatus and a printing paper transport apparatus, and more particularly to a technique suitable for a stencil double-side printing apparatus that includes two sets of plate cylinders and can print both sides of a printing paper.

  A plate cylinder and a pressure roller that can be pressed against the plate cylinder are disposed in a paper conveyance path from the paper feeding device to the paper discharge device of the stencil printing apparatus, and for moving the printing paper in contact with the printing paper. Various conveying or paper feeding members are arranged. For example, FIG. 15 shows a conventional stencil duplex printing apparatus, in which a paper transport path from the paper feeding device 202 to the paper discharge device 203 is formed in the printing apparatus main body 201. One plate cylinder 205, a first pressing roller 206 that can be pressed against the plate cylinder, a second plate cylinder 210 that is positioned closer to the paper discharge device than the first plate cylinder 205, and a second plate cylinder that can be pressed against the second plate cylinder. A pressing roller 211 is disposed. In the vicinity of the sheet forming side of the image forming units A1 and A2 formed between the plate cylinders 205 and 210 and the pressure rollers 206 and 211, paper is placed in the image forming unit in synchronization with the drive timing of the plate cylinders 205 and 210. The timing rollers 207 and 217 are arranged to be fed to the first and second image forming units A1 and A2, and the one-side printed paper is conveyed from the first image forming unit A1 to the second image forming unit A2. A refeeding / conveying belt 220 is disposed.

  When a large number of printing sheets are continuously printed by such a stencil duplex printing apparatus, the sheet on which one side is printed by the first image forming unit A1 is conveyed to the second image forming unit A2 before the ink is dried. Since the other side is to be printed, the printed one-sided ink is transferred to each sheet transporting member disposed on the downstream side of the first image forming unit A1, and this transferred ink is transferred to the rear side. There was a problem that the paper was re-transferred to the printing paper conveyed from the printer and soiled.

  As countermeasures for preventing the paper from being smeared due to the retransfer, for example, there is a method in which minute irregularities are provided on the outer peripheral surface of the second pressing roller 211 or a liquid agent for preventing ink transfer is applied (see Patent Document 1, etc.). ).

Further, the paper processing apparatus after printing is provided with means for removing excess ink on the printing surface of the printing paper with an ink removing liquid on the surface of the contact roller in contact therewith, and means for cleaning the ink removed on the surface of the contact roller. In order to remove excess ink and prevent retransfer of ink from the contact roller to the opposing roller, the opposing roller is formed of an ink repellent material.
JP 2002-219849 A. JP-A-8-132593.

  In the stencil duplex printing apparatus of FIG. 15, the conveyance belt 220 is in contact with the non-printing surface during the conveyance from the first image forming unit A1 to the second image forming unit A2. For this purpose, the vertical relationship between the second plate cylinder 210 and the second pressing roller 211 must be reversed to the vertical relationship between the first plate cylinder 205 and the first pressing roller 206, and the second plate The ink supply mechanism 221 inside the cylinder 210 has to be disposed at the upper end of the second plate cylinder 210, which causes a problem in the compactness of the entire printing apparatus in the vertical direction, and the ink supply mechanism has a space. And the stability of ink supply to the second image forming unit A2 may be impaired. Further, the second timing roller 217 contacts the printing surface immediately after printing by the first image forming unit A1, and the belt of the paper discharge device 203 is just after printing by the second image forming unit A2. There is a high possibility that the printing surface will contact and the ink will be transferred. In addition, when applying the transfer prevention liquid to the second timing roller 217 or the like in the same manner as applying the transfer prevention liquid to the second pressing roller 216, the liquid may run out after a certain period of time after application. Yes, it takes time for maintenance.

  Furthermore, as in Patent Document 2, the structure in which the ink on the printing surface is positively removed by the ink removing liquid is complicated and requires a lot of maintenance.

  In order to solve the above-described problems, the present invention is directed to a rotatable printing cylinder on which a stencil sheet is mounted, an ink supply mechanism for supplying ink to the printing cylinder, and a printing paper sandwiched between the printing cylinder and transported. In the stencil printing apparatus provided with a pressing member for transferring ink to the printing paper, the following features are provided for each member used for feeding the paper to the image forming unit, feeding paper, particularly refeeding and transporting It has.

(1) Timing roller In the vicinity of the image forming unit formed between the plate cylinder and the pressing member, a timing roller and a guide roller that are driven in synchronization with the driving timing of the plate cylinder to sandwich the printing paper and feed it to the image forming unit. An outer peripheral layer made of a fine granular material or an outer peripheral layer made of a solid material having ink repellency is formed on the outer peripheral surface of the timing roller.

(2) Paper feed belt, comprising: a stacking base on which paper on which one side is printed; and a paper feeding belt that feeds out the single-side printed paper stacked on the stacking base in the order of stacking. On the contact surface, an outer peripheral layer coated with fine particles or an outer peripheral layer made of a solid material having ink repellency and having an uneven surface is formed.

(3) Printing paper transport device used inside or outside the stencil printing device In a printing paper transport device that transports paper printed by the printing unit of the stencil printing device to another location, the printing paper is nipped and transported. A pair of rotatable conveyance rollers is provided, and at least an outer peripheral layer that makes point contact with the paper at a plurality of points is formed on the outer peripheral surface of the conveyance roller that contacts at least the paper surface on which the printing ink is transferred.

  As a specific configuration of the outer peripheral layer that makes point contact, an outer peripheral layer made of a fine granular material is formed on the outer peripheral surface of the transport roller that contacts the surface on which the printing ink is transferred. As another configuration, an outer peripheral layer subjected to knurling is formed on the outer peripheral surface of the transport roller that is in contact with the surface on which the printing ink is transferred.

(4) Pressing roller In the stencil printing apparatus, a solid material having an ink repellency, including a timing roller having an outer peripheral layer made of a fine granular material or an outer peripheral layer made of a solid material having ink repellency as described above. And a pressing roller having an outer peripheral layer.

  Further preferably, in the stencil printing apparatus, the timing roller having an outer peripheral layer made of a fine granular material or an outer peripheral layer made of a solid material having ink repellency, and an outer periphery which makes point contact with a printing paper at a number of points. The transport roller having a layer and an outer peripheral layer coated with a fine granular material, or a paper feeding belt made of a solid material having ink repellency and having an outer peripheral layer having an uneven surface, and having ink repellency A pressing roller having an outer peripheral layer made of a solid material is provided.

  An outer peripheral layer of a solid material having ink repellency is formed on an outer peripheral surface of a timing roller, a paper feeding belt, or a conveying roller for feeding, feeding or conveying paper on which at least one side is printed, or a fine granular material By forming the outer peripheral layer, it is possible to prevent the printing surface or the printing paper itself from being stained due to retransfer of the ink in the process of paper feeding or conveyance, and the printing quality can be improved with a simple configuration.

  By forming a layer of fine granular material on the outer peripheral surfaces of the timing roller, the paper feed belt, and the transport roller, it is possible to prevent slippage with the print paper, and to reliably feed or transport the print paper.

  In particular, in a stencil double-sided printing device that has two plate cylinders and prints the front and back surfaces of paper continuously, it occurs at the time of refeeding, transporting, and refeeding to the second plate cylinder after surface printing. Easy ink transfer can be effectively prevented and the utility value is increased.

[Overall structure of stencil duplex printing device]
1 to 4 show a stencil duplex printing apparatus including a timing roller, a refeed belt (feed belt), a transport roller, and a pressing roller according to the present invention. For convenience of explanation, as shown in FIG. 1 which is a schematic front view, the arrangement side of the paper feeding device 2 is referred to as “rear side”, and the arrangement side of the paper discharge device 3 is referred to as “front side”. To do.

  1, the printing apparatus main body 1 is provided with an image reading device 4 on the upper side, an operation panel 5 and a control device 6 on the front side, in addition to the paper discharge device 3 and the paper supply device 2.

  A first printing unit 11 is provided in the latter half of the printing apparatus main body 1, and a second printing unit 12 is provided in the first half in parallel with the first printing unit 11. Are provided with a first and second plate making section 13 and a first and second plate discharging section 14, respectively.

  On the front side of the first printing unit 11, a carry-out belt 28 is provided for carrying the single-side printed paper N printed and discharged by the first printing unit 11 forward.

  Below the first printing unit 11, there is disposed a paper stacking table 30 for refeeding that is inclined forwardly, and between the front end of the paper stacking table 30 and the front end of the carry-out belt 28. , A reverse conveyance device 36 is provided, and a refeeding device 31 with a belt-type suction mechanism inclined at substantially the same angle as the paper stacking table 30 is disposed at the front end of the paper stacking table 30. An intermediate transport device 33 extending in the front upper direction is disposed at the front end of 31, and the intermediate transport device 33 reaches the second timing roller 35 of the second printing unit 12.

[Paper Feeder]
The sheet feeding device 2 includes a sheet feeding table 18, a sheet feeding roller 20, a first timing roller 21, a guide roller 22 that presses against the first timing roller 21, and the like. The printed printing paper N is fed out one by one from the top by the paper feed roller 20 and sent to the timing roller 21. The first timing roller 21 is rotated at an appropriate timing in synchronism with the driving of the first printing unit 11, and sends the printing paper N to the first printing unit 11 in cooperation with the guide roller 22.

[Paper delivery device]
The paper discharge device 3 includes a paper discharge belt 25 having a suction mechanism 26 such as a suction fan, and a paper tray 27 on which double-side printed paper is stacked. The paper discharge belt 25 has a number of through holes. The sheet N on the paper discharge belt 25 is attracted to the paper discharge belt 25 by the suction mechanism 26 disposed below.

[First and second printing sections]
FIG. 2 is a front view of the inside of the printing apparatus main body 1. The first printing unit 11 includes a first plate cylinder 39 in which an ink roller 41 is inscribed and rotated in the direction of arrow R, and the plate cylinder. The first press roller 40 and the like are opposed to the lower surface 39 so as to be capable of being pressed from below, and a plurality of holes are formed in the peripheral wall of the plate cylinder 39, and a stencil sheet which has been made is mounted. ing. An ink supply unit including a squeegee 42 is provided on the outer peripheral surface of the ink roller 41, and ink from an ink tank (not shown) is supplied to the ink supply unit from an ink supply pipe 43. The second printing unit 12 is also composed of a second plate cylinder 39, a second pressing roller 42 and the like that face the plate cylinder 39 so that they can be pressed from below. The corresponding parts are denoted by the same reference numerals and description thereof is omitted.

[Reverse conveying device]
The reverse conveying device 36 includes a belt guide tube 45 that also serves as a suction duct, a rubber reverse conveying belt 46, and the like. The belt guide tube 45 is formed, for example, in a cylindrical box shape using a stainless steel plate, and its upper end is positioned at substantially the same height as the carry-out belt 28 of the first printing unit 11, and the upper half of the front wall surface is a semicircle. It protrudes forward in shape, and its lower half extends linearly downward and rearward at substantially the same inclination angle as the intermediate paper stacking base 30. Rotating rollers 48 and 49 are disposed in the vicinity of the upper and lower ends of the rear wall of the belt guide tube 45. A tension roller 50 is disposed between the rotating rollers 48 and 49. The rollers 48, 49 and 50 and the belt guide The reverse conveying belt 46 is wound around the front wall surface of the tube 45.

  The reverse conveyance path M is formed along the outer periphery of the reverse conveyance belt 46. That is, the reverse conveyance path M protrudes forward from the vicinity of the front end portion (exit end portion) of the carry-out belt 28, wraps around the rear lower side, extends rearward and lower, and extends near the upper front end portion of the intermediate sheet stacking base 30. Is formed. The belt guide cylinder 45 is connected to a suction port of a suction fan (suction mechanism) 52, and the suction fan 52 generates a negative pressure in the belt guide cylinder 45.

  The reversing and conveying device 36 is provided with a reversing and conveying guide 47, which is arranged at a predetermined interval with respect to the front wall of the belt guide tube 45 and along the reversing and conveying path M. Is formed.

  3 is a plan view of a range III portion of FIG. 2. The reverse conveying belt 46 has a large number of suction holes 53 and is divided into, for example, three sheets at intervals in the left-right direction. A plurality of suction ports 54 are formed on the peripheral wall at positions corresponding to the reversal conveyance belts 46, and the paper on the reversal conveyance belt 46 is sucked from the suction ports 54. The suction port 54 is formed in a strip shape along the reverse conveyance path.

  The reverse conveyance guide 47 is made of, for example, a thin rod-shaped member made of stainless steel, and a total of five are arranged.

[Paper stack for refeeding]
In FIG. 2, the paper stacking base 30 includes a bottom plate 58, a rear plate 59 erected on the upper surface of the bottom plate 58 so that the front and rear positions can be adjusted, and a pair of left and right side plates 60 erected so that the left and right positions can be adjusted. It is configured. A guide plate 61 made of a flexible resin band plate is disposed above the paper stacking table 30, and the front upper end portion of the guide plate 61 is fixed to the upper part of the exit of the reverse conveyance path M, As it goes rearward, it inclines so as to approach the bottom plate 58 of the paper stacking table 30, and the rear end portion can contact the bottom plate 58 at a position near the rear plate 59.

[Refeeder and blower]
In FIG. 4, the paper refeed device 31 includes a pair of front and rear rollers 65, a paper feed belt 66 wound around the rollers 65, and a suction duct / belt guide cylinder 67. Is linked to a drive motor 88.

  As an example, the paper feed belt 66 is divided and arranged in five rows or seven rows at intervals in the left-right direction. The belt guide cylinder 67 communicates with the suction fan 69, and suction ports 68 are formed at positions corresponding to the left and right sides of each refeed belt 66, so that the sheet can be adsorbed to the refeed belt 66. Yes. Each suction port 68 is formed in a rectangular shape that is long in the front-rear direction.

  A blower 71 is disposed on the front side of the paper re-feed device 31 in order to separate the lowermost paper and the second or more paper and to dry them at the time of paper feeding. The blower 71 includes a duct 72 communicating with the blower fan 73 and a blower guide plate 74 that opens rearward from the rear surface of the duct 72, and faces the lower end portion of the front edge of the stacked sheets N. It comes to blow.

  As shown in FIG. 2, an auxiliary air blower (blower fan) 64 is also arranged behind the paper stacking base 30, and is attached to the rear end of the stacked paper N on the stacking base 30 through a hole formed in the rear plate 59. It is designed to send the wind.

[Intermediate transfer device]
In FIG. 2, the intermediate transport device 33 is composed of a plurality of transport guide plates 81 and a plurality of pairs of transport rollers 80 and the like that are disposed to face each other so as to sandwich the transport guide plate 81. The conveyance guide plate 81 is divided into a plurality from the front end of the refeed device 31 to the second timing roller 35 of the second printing unit 12, and each pair of the conveyance rollers 80 is spaced from the conveyance path. It is placed and placed.

  In FIG. 3 showing a plan view, the conveyance guide plate 81 is made of a resin band plate, and is divided and arranged in a plurality of examples at intervals in the left-right direction, for example. The conveyance roller 80 is formed in a portion between the conveyance guide plates 81 of the roller shaft 81a.

[Pressure roller structure]
FIG. 5 is an enlarged perspective view of the second printing unit 12, and the second pressing roller 42 disposed below the plate cylinder 39 is rotatably supported by a swing arm 100 that can swing up and down. The roller shaft 101 has a rubber (for example, NBR) cylindrical roller portion (main body) 103 fixed to the outer periphery of the roller shaft 101, and the outer peripheral surface of the roller portion 103 is in accordance with the present invention. An outer peripheral layer 104 made of a solid material having ink repellency is formed. The ink repellency is basically oil repellency since it is based on the use of water-in-oil emulsion type ink. The ink used in the stencil printing apparatus is an emulsion type. For example, the water-in-oil type has a configuration in which the oil 111 wraps around the outer periphery of the water 110 and the pigment is dispersed in the oil 111 as shown in FIG. In contrast, in the case of the oil-in-water type, ink repellency means water repellency, and it is necessary to correspond to the ink used.

  As the solid material forming the outer peripheral layer 104 of the second pressing roller 42, polyester resin, fluorine resin, or silicon rubber is used, and none of the materials has affinity for ink. It has ink repellency.

  As a method for forming the outer peripheral layer 104 of the second pressing roller 42, a resin material for forming an outer peripheral layer in the form of a tape or a film can be coated.

[Second Timing Roller Structure]
FIG. 7 is a perspective view of the second timing roller 35 of the second printing unit 12. A plurality of roller units 121 are fixed to the outer periphery of the roller shaft 120 at intervals in the axial center direction. 121 is formed of a metal such as nitrile rubber (NBR) or aluminum, and the outer peripheral layer 122 formed on the outer periphery of the roller portion 121 has one of the following structures according to the present invention.

(1) The outer peripheral layer 122 made of a solid material having ink repellency is formed. For example, the outer peripheral layer 122 is formed of a fluorine-based resin having ink repellency.

(2) The outer peripheral layer 122 made of fine particles is formed. For example, the outer peripheral layer 122 is formed by coating the outer peripheral surface of the roller portion 121 with powder ceramic (# 240 or # 600). As the coating method, there are a method in which the powder ceramic of the paint is dispersed and sprayed, a method in which an adhesive is applied to the outer peripheral surface and the powder ceramic is adhered, or a method in which the powder ceramic is sprayed on the outer peripheral surface. Applicable. In this case, the roller part 121 is made of metal such as aluminum.

(3) As described above, it is possible to form the outer peripheral layer 122 with fine particles and to apply an ink repellent material.

  As shown in FIG. 8, the guide roller 37 arranged to face the second timing roller 35 can swing around the support shaft 131, and is synchronized with the second plate cylinder 39 to be the second timing roller. The printing paper N is held between It is possible to form an outer peripheral layer similar to the second timing roller 35 on the outer peripheral surface of the guide roller 37.

[Structure of paper feed belt]
FIG. 11 is a partially enlarged perspective view of the paper feed belt 66 of the refeed device 31. The main body portion of the paper feed belt 66 is formed of ethylene propylene rubber (EPDM), and the outer peripheral layer formed on the outer periphery of the main body portion. 126 has one of the following structures according to the present invention.

(1) The outer peripheral layer 126 coated with fine particles is formed. For example, the outer peripheral layer 126 is formed so that the surface roughness is about # 400 of sandpaper.

(2) The outer peripheral layer 126 made of a solid material having ink repellency is formed. For example, the outer peripheral layer 126 equivalent to the surface of the high-quality crepe paper having irregularities on the surface and ink repellency is formed.

[Conveyor roller structure]
FIG. 9 is a perspective view of the conveying roller 80 of the intermediate conveying device 33. A plurality of roller portions 132 are fixed to the outer periphery of the upper and lower roller shafts 80a at intervals in the axial direction. The main body portion is formed of a metal such as nitrile rubber (NBR) or aluminum, but as shown in FIG. 10, the lower roller portion 132 that contacts the printing surface of the single-side printed paper is made of a metal such as aluminum. According to the present invention, the outer peripheral layer 133 is in contact with the paper at a number of point contacts. The specific structure of the outer peripheral layer is one of the following.

(1) By performing knurling on the outer peripheral surface, for example, the outer peripheral layer 133 having a knurled surface with an iris pattern (M = 0.2) is formed.

(2) The outer peripheral layer 133 made of fine particles is formed. For example, the outer peripheral layer 133 is formed by coating the outer peripheral surface with powder ceramic (# 240, # 600 or the like). As the coating method, as in the case of the timing roller 35, the powder ceramic of the paint is dispersed and spray-coated, the method of applying the adhesive to the outer peripheral surface and bonding the powder ceramic, or the powder ceramic on the outer periphery. A method of spraying on the surface can be applied.

(3) As described above, it is possible to form the outer peripheral layer 133 with fine particles and to apply an ink repellent material.

[Printing process]
(1) In FIG. 1, the image reading device 4 reads the front and back surfaces of the document, respectively, makes the plates by the first and second plate making sections 13, and makes the stencil sheet (master) after the plate making each plate cylinder. Attach to 39.

(2) When printing is started, the printing paper on the paper feed tray 18 is continuously fed out one by one by the paper feed roller 20, and the first timing roller 21 rotates the plate cylinder 39 of the first printing unit 11. Synchronously, it is fed into the lower end image forming portion of the plate cylinder 39, and one side (upper surface) of the paper is printed.

(3) In FIG. 2, the paper on which one side is printed by the first printing unit 11 is sent to the reverse conveying device 36 via the carry-out belt 28, and due to the negative pressure in the belt guide cylinder 45 that also serves as a suction duct, The unprinted surface (lower surface) is attracted to the outer peripheral surface of the reverse conveying belt 46. Then, in the adsorbed state, the sheet is conveyed in the curved reversal conveyance path M and discharged from the rear lower end exit of the reversal conveyance path M onto the paper stacking table 30.

(4) When a certain number of single-sided printing sheets are stacked on the sheet stacking table 30, the paper refeed device 31, the intermediate transport device 33, the second printing unit 12, and the paper discharge device 3 are started, and the sheet stacking table is started. The 30 single-sided printed sheets are re-feeded in the stacking order, conveyed, supplied to the second printing unit 12, and the other side is printed.

(5) In the paper refeed process by the paper refeed device 31, the lowermost sheet of the paper stacking base 30 is sent out to the front upper side with its print surface (lower surface) adsorbed by the paper feed belt 66. As shown in FIG. 11, an outer peripheral layer 126 coated with a concavo-convex surface having ink repellency or a fine granular material is formed on the outer peripheral surface of the paper belt. It is prevented. Also, slipping of the printing paper can be prevented.

(6) In FIG. 2, the single-side printed paper fed out by the refeed device 31 is sandwiched between the upper and lower transport rollers 80, and transported forward and upward on the guide plate 81 by the rotation of the transport rollers 80. The In the conveyance process by the conveyance roller 80, the printing surface (lower surface) of the sheet comes into contact with the lower conveyance roller 80 and is conveyed to the front and upper. The roller portion of the lower conveyance roller 80 as shown in FIG. Since the outer peripheral surface 133 is formed with the knurled or powder ceramic coating on the outer peripheral surface 132 as described above, the transfer of ink to the transport roller 80 is prevented.

  In FIG. 2, the single-sided printed paper conveyed to the second timing roller 35 by the intermediate conveying device 33 is sandwiched between the guide roller 37 and the second timing roller 35 as shown in FIG. In synchronization with the plate cylinder 39 of the section 12, the sheet is fed to the lower end image forming portion of the plate cylinder 39, and the other side of the sheet is printed. At this time, the second timing roller 35 comes into contact with the printing surface of the single-side printed paper, but the outer peripheral surface of the second timing roller 35 is the outer peripheral layer 122 or the powder having ink repellency as described above. Since the outer peripheral layer 122 is coated with a body ceramic or the like, the transfer of ink to the second timing roller 35 is reduced.

(7) In FIG. 2, the paper on which the other surface is printed by the second printing unit 12 is in a double-sided printing state, and is discharged to the paper receiving tray 27 via the discharge belt 25 with the suction mechanism 26. At this time, the printing surface immediately after printing by the second printing unit 12 is located on the upper side, and the lower surface side where the ink has already dried is adsorbed to the carry-out belt 25, so that the ink is transferred to the discharge belt 25. There is nothing.

  In this embodiment, the outer periphery of the first timing roller 21 and the first pressing roller 40 of the first printing unit 11 is similar to the second timing roller 35 and the second pressing roller 42, respectively. It is also possible to form the outer peripheral layers 122 and 104.

  FIG. 12 shows a printing result obtained by examining the retransfer state by the paper feeding belt 66 of the paper feeding device 31. Four types (test Nos. 1-1 to 1-4) of the paper feeding belts 66 having different outer peripheral surface structures are shown. 2 are sequentially applied to the refeeding device 31 of the stencil duplex printing apparatus shown in FIG. 2, and the single-sided printed paper immediately after being fed again from the paper stacking base 30 by the paper feeding belt 66 is extracted, and the degree of contamination of the printing paper Was examined visually. That is, surface printing → reversal → stacking on an intermediate stacking board → refeeding → sampling confirmation. The test conditions are as follows.

[Test conditions]
Printing paper: Three types of paper were used: high-quality paper, extra-thin high-quality paper, and rough paper.

  Ink: Black was used as the ink for the first printing section and green was used as the ink for the second printing section so that the distinction between the front and back sides became clear.

  Buffering time: 30 sheets of paper were allowed to stay for 20 seconds on the intermediate paper stacking table 30.

  Printing speed: Both the first and second printing sections were printed at a third speed (plate cylinder rotation speed, approximately 78 to 82 rpm).

  Printing density and plate making density: Both the first and second printing sections were printed at standard density.

  Number of printed sheets: The standard was printed 100 sheets.

  Sampling interval and state confirmation method: Single-sided printed paper immediately after being re-fed from the paper feeding belt 66 was taken out every ten sheets from the first, and the transfer state was visually confirmed.

[Configuration and test results of paper feed belt]
Test no. 1-1, in the refeed device 31 provided with seven (or five) paper feed belts 66 in parallel at intervals, all the paper feed belts 66 are made from only the main body portion of ethylene propylene rubber. The configuration. That is, the re-feeding device 31 does not take any transfer prevention measures according to the present invention. This test No. In 1-1, in any case of high-quality paper, extra-thin high-quality paper, and rough paper, irregular rubbing stains and belt-like pattern stains were confirmed.

  Test No. 1-2 is a refeed device 31 having seven paper feed belts 66 arranged in parallel at intervals, and a drafting tape is attached to the outer peripheral surface of one central paper feed belt 66, and the remaining six are It was set as the structure which consists only of the main-body part of ethylene propylene rubber. That is, the paper re-feeding device 31 is in a state in which almost no transfer prevention measures according to the present invention are taken. This test No. In 1-2, parts other than the part corresponding to the paper feeding belt to which the drafting tape is attached are the same as those in Test No. 1 above. The same dirt as 1-1 was confirmed.

  Test No. 1-3 is a refeed device 31 having seven paper feed belts 66 arranged in parallel at intervals, and a drafting tape is stuck on the outer peripheral surface of the middle five paper feed belts 66, and the remaining two ends 2 The book consisted of only ethylene propylene rubber body. In other words, the sheet feeding device is substantially in a state where the measures for preventing transfer according to the present invention have been substantially taken. This test No. In 1-3, the above test No. Dirts such as 1-1 and 1-2 were substantially eliminated.

  Test No. 1-4 shows a paper refeed device 31 having five paper feed belts 66 parallel to each other at intervals as shown in FIG. 400), and the remaining two ends are composed of only ethylene propylene rubber main body. In other words, the paper re-feeding apparatus is substantially in a state in which the measures for preventing transfer according to the present invention are taken. This test No. In 1-4, no contamination was observed.

  From the above, as the paper feeding belt 66, the sandpaper is pasted on the surface to form the outer peripheral layer 126 coated with the fine granular material, or the drafting tape is pasted to make the ink repellency. It has been found that the best results can be obtained by forming an outer peripheral layer having a concavo-convex surface and made of a solid material having a surface.

  FIG. 13 is a print result of examining the retransfer state by the transport roller 80 of the intermediate transport device 33, and shows five types (test Nos. 2-1 to 2-5) of the transport roller 80 having different outer peripheral surface structures. 2 is sequentially applied to the intermediate conveyance device 33 of the stencil duplex printing apparatus shown in FIG. 2, and the single-sided printed paper immediately after the conveyance by the intermediate conveyance device 33 is extracted, and the degree of contamination of the printing paper is visually examined. That is, surface printing → reversal → stacking on an intermediate stacking board → refeeding → intermediate transport → sampling confirmation. However, the paper feeding belt 66 of the paper re-feeding device 31 was tested No. The configuration of 1-4, that is, the one in which sandpaper was stuck to three of the five paper feeding belts 66 was used. Other test conditions are the same as those in Example 1.

[Conveyor roller configuration and test results]
Test No. 1 in FIG. In Example 2-1, the outer peripheral surface of the aluminum roller portion 132 of the lower conveying roller 80 was wrapped with a polyolefin heat shrinkable tube. That is, the transport roller is in a state in which the transfer prevention measure according to the present invention is not taken. This test No. In 2-1, rubbing stains were confirmed in any of high-quality paper, extra-thin high-quality paper, and rough paper.

  Test No. In 2-2, the outer peripheral surface of the aluminum roller portion 132 of the lower conveying roller 80 was wrapped with a fluorine-based heat-shrinkable tube. That is, the transport roller is in a state in which the transfer prevention measure according to the present invention is not taken. This test No. Also in 2-2, rubbing stains were confirmed in all cases of high-quality paper, extra-thin high-quality paper, and rough paper.

  Test No. 2-3 is a configuration in which an outer peripheral layer 133 having a module M = 0.2 and a knurled surface of an iris pattern is formed on the outer peripheral surface of the aluminum roller portion 132 of the lower conveying roller 80. That is, the conveyance roller is provided with a transfer prevention measure according to the present invention. This test No. In 2-3, no stain was observed in any of the high-quality paper, extra-thin high-quality paper, and rough paper.

  Test No. In 2-4, the outer peripheral surface of the aluminum roller portion 132 of the lower conveying roller 80 is coated with powder ceramic (# 240). That is, the conveyance roller is provided with a transfer prevention measure according to the present invention. This test No. In 2-4, no stain was observed in any of the high-quality paper, extra-thin high-quality paper, and rough paper.

  Test No. 2-5 is a configuration in which the outer peripheral surface of the aluminum roller portion 132 of the lower conveying roller 80 is coated (# 640) with a powder ceramic having a particle diameter different from that of the test No. 2-4. 2 is a conveying roller to which a transfer prevention measure according to the present invention is applied. Test No. in this table. In 2-5, no stain was observed in any of the high-quality paper, extra-thin high-quality paper, and rough paper.

  FIG. 14 is a printing result of examining the retransfer state by the second timing roller 35 and the second pressing roller 42 in the second printing unit 12 of FIG. 2, and four types of second types having different outer peripheral surface structures. Various combinations of the timing roller 35 and five types of second pressure rollers 42 having different outer peripheral surface structures, and a total of nine combinations (test Nos. 3-1 to 3-9), are shown in FIG. 1 and FIG. The paper is applied to the printing unit 12 and the second timing roller 35 in sequence, the double-sided printed paper immediately after the end of the other side printing is extracted, and the degree of contamination of the printing paper is visually examined. That is, surface printing → reversal → stacking on the intermediate stacking board → refeeding → intermediate transport → feeding by the second timing roller → other surface printing → sampling confirmation. However, for the paper feeding belt 66 of the refeeding device 31, the configuration of Test No. 1-4, in which no contamination was observed in the first embodiment, was used, and the conveying roller 80 of the intermediate conveying device 33 was used. Test No. in which no contamination was observed in Example 2 above. The configuration 2-5 was used. Other test conditions are the same as those in Example 1.

[Configuration and test results of second timing roller and second pressing roller]
Test No. in FIG. 3-1, the second timing roller 35 and the second pressing roller 42 are both configured by only NBR roller parts 121 and 103. That is, the second timing roller 35 and the second pressing roller 42 in a state in which the transfer prevention measure according to the present invention is not taken. This test No. In 3-1, many rubbing stains were confirmed in all cases of high-quality paper, extra-thin high-quality paper, and rough paper.

  Test No. In 3-2, the outer peripheral surface of the roller portion 121 of the second timing roller 35 is wrapped with a fluorine-based heat-shrinkable tube, while the second pressing roller 42 has only the NBR roller portion 103. That is, the second timing roller 35 is subjected to the transfer prevention measure according to the present invention, and the second pressure roller 42 is not subjected to the transfer prevention measure according to the present invention. This test No. In No. 3-2, rubbing stains were present in any of the fine paper, extra-thin fine paper, and rough paper. The dirt was slightly eliminated as compared with the case of 3-1. That is, by enclosing the roller portion 121 of the second timing roller 35 with a fluorine heat shrinkable tube, the test No. Compared to 3-1, it is presumed that the re-transfer by the second timing roller 35 is eliminated, and thereby the dirt is somewhat eliminated.

  Test No. In 3-3, the second timing roller 35 has only the NBR roller portion 121, and the second pressing roller 42 has a configuration in which a polyester tape 104a is wound around the outer periphery of the roller portion 103 as shown in FIG. That is, the second timing roller 35 is not subjected to the transfer prevention measure according to the present invention, and the second pressing roller 42 is in the state where the transfer prevention measure according to the present invention is applied. This test No. In No. 3-3, rubbing stains were present in any of the high-quality paper, extra-thin high-quality paper, and rough paper. The dirt was slightly eliminated as compared with the case of 3-1. That is, by winding a polyester tape around the second pressing roller 42, the test No. Compared to 3-1, it is presumed that the re-transfer by the second pressing roller 42 is eliminated, and the dirt is somewhat eliminated.

  Test No. 3-4 to 3-9 are states in which the outer peripheral surfaces of the roller portions 121 and 103 of the second timing roller 35 and the second pressing roller 42 are subjected to the transfer prevention measures according to the present invention. Test No. In 3-4 to 3-9, no stain was observed in any of the high-quality paper, extra-thin high-quality paper, and rough paper.

  That is, test no. 3-4 is a configuration in which the outer peripheral surface of the second timing roller 35 is wrapped with a fluorine-based heat-shrinkable tube, and a polyester tape is wound around the outer peripheral surface of the roller portion 103 of the second pressing roller 42. Test No. 3-5, the roller portion 121 of the second timing roller 35 is made of aluminum, the outer peripheral surface of the roller portion 121 is coated with powder ceramic (# 240), and the roller portion 103 of the second pressure roller 35 is coated. It is the structure which wound the polyester tape around the outer peripheral surface. Test No. Reference numeral 3-6 denotes a configuration in which the outer peripheral surface of the second timing roller 35 is wrapped with a fluorine heat shrinkable tube, and a PET (polyethylene terephthalate) film is wound around the outer peripheral surface of the roller portion 103 of the second pressing roller 35. Test No. 3-7, the roller portion 121 of the second timing roller 35 is made of aluminum, the outer peripheral surface of the roller portion 121 is coated with powder ceramic (# 600), and the roller portion 103 of the second pressure roller 42 is coated. It is the structure which wound PET film around the outer peripheral surface. Test No. 3-8, the roller portion 121 of the second timing roller 35 is made of aluminum, and the outer peripheral surface of the roller portion 121 is coated with powder ceramic (# 240), and the roller portion 103 of the second pressing roller 42 The outer peripheral surface of is wrapped with a fluorine-based heat-shrinkable tube. Test No. 3-9, the roller portion 121 of the second timing roller 35 is made of aluminum, the outer peripheral surface of the roller portion 121 is coated with powder ceramic (# 640), and the outer peripheral surface of the roller portion 103 of the pressing roller 42 Is wound with an offset master for offset printing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic front view showing a stencil double-sided printing apparatus to which the present invention is applied, seeing through the inside. It is an enlarged front view which shows the structure of the principal part in the stencil duplex printing apparatus of FIG. FIG. 3 is a plan view corresponding to the range III-III in FIG. 2. FIG. 4 is a plan view of a paper stacking base and an intermediate paper feeding device. It is an expansion perspective view of a printing part. It is a front view which shows an example of the surface processing method of a press roller. It is a perspective view of a timing roller. It is a front enlarged view of a timing roller. It is a perspective view of a conveyance roller. It is a front view of a conveyance roller. FIG. 4 is a partially enlarged perspective view of a paper feeding belt. 7 is a result table of a paper smear test by retransfer of a paper feed belt, which is Embodiment 1 of the present invention. FIG. 10 is a table showing a result of a paper smearing test by retransfer of a conveyance roller, which is Example 2 of the present invention. It is Example 3 of this invention, and is a result table | surface of the paper stain test by retransfer of a pressure roller or a timing roller. It is the longitudinal cross-section schematic of a prior art example. It is a structure schematic diagram of the ink used for printing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 1st printing part 12 2nd printing part 21 1st timing roller 30 Intermediate paper stacking base 31 Refeed device 33 Intermediate conveyance device 35 Second timing roller 36 Reverse conveyance device 80 Conveyance roller 81 Conveyance guide plate 104 Outer peripheral layer 122 of the pressing roller Outer peripheral layer 126 of the second timing roller Outer peripheral layer 133 of the sheet feeding belt Outer peripheral layer of the conveying roller

Claims (10)

A rotatable plate cylinder on which a stencil sheet is mounted, an ink supply mechanism for supplying ink to the plate cylinder, and a pressure for transferring the ink to the printing paper by sandwiching and transporting the printing paper between the plate cylinder In a stencil printing apparatus provided with a member,
In the vicinity of the image forming unit formed between the plate cylinder and the pressing member, a timing roller and a guide roller that are driven synchronously with the driving timing of the plate cylinder and sandwich the printing paper and are sent to the image forming unit are opposed to each other,
A stencil printing apparatus, wherein an outer peripheral layer made of a fine granular material is formed on the timing roller. A rotatable plate cylinder on which a stencil sheet is mounted, an ink supply mechanism for supplying ink to the plate cylinder, and a pressure for transferring the ink to the printing paper by sandwiching and transporting the printing paper between the plate cylinder In a stencil printing apparatus provided with a member,
In the vicinity of the image forming unit formed between the plate cylinder and the pressing member, a timing roller and a guide roller that are driven synchronously with the driving timing of the plate cylinder and sandwich the printing paper and are sent to the image forming unit are opposed to each other,
A stencil printing apparatus, wherein an outer peripheral layer made of a solid material having ink repellency is formed on the timing roller. A rotatable plate cylinder on which a stencil sheet is mounted, an ink supply mechanism for supplying ink to the plate cylinder, and a pressure for transferring the ink to the printing paper by sandwiching and transporting the printing paper between the plate cylinder In a stencil printing apparatus provided with a member,
A stacking base for stacking sheets on which one side is printed, and a paper feeding belt for feeding out the single-sided printed sheets stacked on the stacking base in the stacking order;
A stencil printing apparatus, wherein an outer peripheral layer coated with a fine granular material is formed on a paper contact surface of the paper feed belt. A rotatable plate cylinder on which a stencil sheet is mounted, an ink supply mechanism for supplying ink to the plate cylinder, and a pressure for transferring the ink to the printing paper by sandwiching and transporting the printing paper between the plate cylinder In a stencil printing apparatus provided with a member,
A stacking base for stacking sheets on which one side is printed, and a paper feeding belt for feeding out the single-sided printed sheets stacked on the stacking base in the stacking order;
A stencil printing apparatus, wherein an outer peripheral layer made of a solid material having ink repellency and having an uneven surface is formed on a paper contact surface of the paper feed belt. In a printing paper transport device that transports paper printed by the printing unit of a stencil printing device to another location,
Provided with a pair of rotatable transport rollers that sandwich and transport printing paper,
Printing is characterized in that an outer peripheral layer that makes point contact with the printing paper at a number of points is formed on the outer peripheral surface of the conveying roller that contacts at least the paper surface to which the printing ink is transferred. Paper transport device. In the printing paper conveyance apparatus of Claim 5,
A printing paper transport apparatus, wherein an outer peripheral layer made of a fine granular material is formed on an outer peripheral surface of a transport roller contacting a paper surface to which printing ink is transferred. In the printing paper conveyance apparatus of Claim 5,
An apparatus for conveying a printing paper, wherein a knurled outer circumferential layer is formed on an outer circumferential surface of a conveying roller that contacts a paper surface to which printing ink is transferred. In the stencil printing apparatus according to claim 1 or 2,
A stencil printing apparatus, wherein an outer peripheral layer made of a solid material having ink repellency is formed on the pressing member. The stencil printing apparatus according to claim 8,
A stacking table on which sheets on which one side is printed are stacked, a sheet feeding belt that sucks out one-side printed sheets stacked on the stacking table in the stacking order, and a pair of rotatable transport rollers that sandwich and transport the printing sheets. With
On the paper contact surface of the paper feed belt, an outer peripheral layer coated with a fine granular material is formed,
A stencil printing apparatus, wherein at least an outer peripheral surface of a conveying roller that contacts a paper surface to which printing ink is transferred is formed with an outer peripheral layer that makes point contact with the paper at a plurality of points. The stencil printing apparatus according to claim 8,
A stacking table on which sheets on which one side is printed are stacked, a sheet feeding belt that sucks out one-side printed sheets stacked on the stacking table in the stacking order, and a pair of rotatable transport rollers that sandwich and transport the printing sheets. With
On the paper contact surface of the paper feed belt, a layer made of a solid material having ink repellency and having an uneven surface is formed,
An stencil printing apparatus, wherein an outer peripheral layer that makes point contact with a plurality of points is formed on at least an outer peripheral surface of a conveying roller that contacts a paper surface to which printing ink is transferred.

Images