JP2006248767A - Double-sided image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-sided image forming device such as a double sided printer for preventing a skew in a paper refeeding tray of paper printed on the other surface thereafter, in the paper printed on one surface. <P>SOLUTION: This double sided image forming device has the paper refeeding tray 45 for placing the paper 36 for forming an image on one surface, that is, the paper 36 for forming an image on the other surface thereafter, and a skew preventive means 151 for preventing the skew of the paper 36 on the paper refeeding tray 45 by engaging with the paper 36, and has skew preventive members 59a and 59b rotatable when the skew preventive means 151 engages with the side edge of the paper 36 and preventing the skew of the paper 36. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a stencil printing apparatus having a refeed tray and capable of forming an image on both sides of a sheet.

  Conventionally, various image forming apparatuses such as stencil printing apparatuses shown in, for example, [Patent Document 1] to [Patent Document 4] have been used. In recent years, paper consumption and documents, For the purpose of reducing file storage space, etc., double-sided image formation that forms images on both sides of a sheet tends to increase. Conventionally, the paper loaded in the paper feed tray is passed through the image forming unit, and after forming an image on one side, the paper is turned over and set in the paper feed tray, and again passed through the image forming unit to form an image on the other side. Double-sided image formation was performed by this, but it is necessary to align the paper that has been ejected once, set the paper that has been ejected once again to the paper feed tray, and print on one side of the stencil printing machine. After completion, it is necessary to perform plate making for printing on the other side, and there are problems that work is troublesome and time is lost, and in the case of stencil printing devices, the consumption of raw paper increases. There was also a problem of high costs.

Accordingly, various image forming apparatuses capable of forming images on both sides without performing manual refeeding with one apparatus have been proposed. For example, as such a duplex printing apparatus, [Patent Document 3], A double-sided printing apparatus described in [Patent Document 4] has been proposed.
The double-sided printing apparatus described in [Patent Document 3] and [Patent Document 4] is capable of printing on both sides in one pass, suppresses enlargement, and makes a masterless master for preventing ink transfer during single-sided printing. From the viewpoint of suppressing the waste of the master due to winding of the sheet, a single plate cylinder is used, and a divided plate-making master in which the first plate-making image and the second plate-making image are arranged in two directions in the rotation direction of the plate cylinder is used. A first print image corresponding to one plate-making image is printed on one side of the paper, and the paper is switched back, and then a second print image corresponding to the other plate-making image is printed on the other side of the paper. A double-sided printed material is obtained in the process.

  As described above, the image forming apparatus that performs double-sided image formation by switching back the paper includes a refeed tray that stacks the sheets when the paper is switched back, and refeeds from the refeed tray. In general, it is performed toward the image forming unit.

JP-A-6-48014 JP-A 64-24783 JP 2003-200355 A JP 2004-224479 A

However, if the paper to be switched back is in a skewed state, the paper is fed again in a skewed state, and the first side image and the second side image are formed at different positions. An image position shift called a resist or the like occurs.
The skew of the paper also occurs in an electrostatic development type image forming apparatus such as a copying machine or a printer. However, the paper is fed from a plate cylinder or the like such as a stencil printing apparatus described in [Patent Document 1] to [Patent Document 4]. It is particularly likely to occur in a printing apparatus that peels off. Even if this is a printing apparatus equipped with various means for peeling the paper from the plate cylinder or the like, the unevenness of the air flow for peeling the paper from the plate cylinder, for example, sprayed by a peeling fan or the like occurs. This is because there is a case where the paper is not uniformly peeled from the paper, and the paper is not uniformly peeled from the plate cylinder due to the size or deviation of the print image, the stiffness of the paper, etc. Because there is.

  If the paper to be re-fed is skewed, even if the degree of re-feeding is small, the degree of skew is increased in the re-feeding process. Deviation may occur greatly. Since image misregistration degrades the image quality when double-sided image formation is performed, in order to perform high-quality double-sided image formation, skew feeding of paper to be re-fed is prevented, and image misregistration is performed. Need to prevent.

  The present invention provides a double-sided image forming apparatus, such as a double-sided printing apparatus, that prevents a skew of a sheet printed on one side and then printed on the other side on a refeed tray. With the goal.

  In order to achieve the above object, the invention described in claim 1 is a sheet re-feeding tray on which an image is formed on one side, and a sheet on which an image is formed is placed on the other side, A skew prevention means for engaging the paper and preventing the skew of the paper on the refeed tray, and the skew prevention means is rotatable when engaged with the side edge of the paper. The double-sided image forming apparatus has a skew prevention member for preventing the skew of the sheet.

  According to a second aspect of the present invention, in the double-sided image forming apparatus according to the first aspect, the skew feeding preventing member is disposed and paired with each side edge of the paper.

  According to a third aspect of the present invention, in the double-sided image forming apparatus according to the first or second aspect, the skew prevention member is movable in the width direction of the paper.

  According to a fourth aspect of the present invention, there is provided the double-sided image forming apparatus according to the third aspect, wherein the double-sided image forming apparatus is dependent on the double-sided image forming apparatus according to the second aspect. When positioned between the members, the pair of skew prevention members occupy a position where the interval is substantially the same as the width of the sheet.

  According to a fifth aspect of the present invention, in the double-sided image forming apparatus according to the third or fourth aspect, the skew feeding preventing member is driven in the width direction, and the skew feeding preventing member is controlled by controlling the driving means. And a control means for displacing.

  According to a sixth aspect of the present invention, in the double-sided image forming apparatus according to the fifth aspect, when the control unit is located between the pair of skew feeding prevention members, the control unit prevents the skew feeding. The member is displaced between a first position where the member is engaged with the sheet to prevent skewing of the sheet and a second position which is separated from the sheet.

  According to a seventh aspect of the present invention, in the double-sided image forming apparatus according to the fifth or sixth aspect, the tray on which the sheets on which image formation is performed can be displaced in the width direction of the sheets stacked on the tray. A guide member for engaging the side edge of the paper to position the paper on the tray, and a detecting means for detecting the position of the guide member in the width direction of the paper, and the control means The skew prevention member is displaced based on the position of the guide member detected by the detection means.

  According to an eighth aspect of the present invention, in the double-sided image forming apparatus according to any one of the first to seventh aspects, the skew prevention member has a shape whose diameter decreases upward. And

  The invention according to claim 9 is the stencil printing apparatus in the double-sided image forming apparatus according to any one of claims 1 to 8.

  The present invention relates to a sheet having an image formed on one side thereof, on which a sheet to be imaged on the other side is placed, and a paper refeeding tray engaged with the sheet. A skew prevention means for preventing skew of the same sheet on the upper side, and the skew prevention means is rotatable when engaged with a side edge of the sheet and prevents the skew of the sheet. In the double-sided image forming apparatus having the skew feeding prevention member, the sheet on which the image is formed on one side and the sheet on which the image is formed on the other side is then skewed on the refeed tray. The skew prevention member is prevented by engaging with the side edge of the paper, and is not rotatable, so that the conveyance of the paper when engaged with the paper is not hindered. Double-sided image that can form high-quality double-sided images without any occurrence It is possible to provide the forming apparatus.

  If the skew prevention member has a pair of skew prevention members disposed on each side edge of the sheet, the sheet has an image formed on one side, and then the other side. The skew feeding of the paper on which the image is formed on the refeed tray is better prevented by the pair of skew feeding preventing members engaging each side edge of the paper, and the paper can be rotated. It is possible to provide a double-sided image forming apparatus capable of performing high-quality double-sided image formation without hindering the conveyance of the paper when engaged with the paper, and thus without causing an image position shift. .

  If the skew feeding prevention member is movable in the width direction of the paper, it is a paper on which an image is formed on one side, and then an image is formed on the other side in various sizes. When skewing of the paper on the refeed tray is satisfactorily prevented by the pair of skew prevention members engaging each side edge of the paper, and when the paper is engaged by being rotatable, Therefore, it is possible to provide a double-sided image forming apparatus capable of forming a high-quality double-sided image without causing a hindrance to the conveyance of the paper, and thus without causing an image position shift.

  When at least the paper is positioned between the pair of skew prevention members, the pair of skew prevention members occupies a position where the interval is substantially the same as the width of the paper. A pair of skew prevention members that form a pair of sheets of paper of various sizes, which are formed on one side and then formed on the other side, on the refeed tray. By engaging each side edge of the paper, it is better and reliably prevented, and by being rotatable, it does not hinder the conveyance of the paper when it is engaged with the paper, so that the image misalignment is prevented. It is possible to provide a double-sided image forming apparatus capable of forming a high-quality double-sided image without occurrence.

  If it has drive means for driving the skew prevention member in the width direction and control means for controlling the drive means to displace the skew prevention member, the sheet on which an image is formed on one side In this case, the skew feeding prevention member that makes a pair of skews on the refeed tray of various sizes of paper that is imaged on the other side is engaged with each side edge of the paper. Therefore, it is possible to prevent high-quality double-sided images easily without preventing the paper from being transported when engaged with the paper. It is possible to provide a double-sided image forming apparatus capable of forming.

  When the paper is positioned between the pair of skew feeding prevention members, the control means engages the pair of skew feeding prevention members with the paper to prevent the paper from skewing. If the displacement is made between the position 1 and the second position separated from the sheet, the sheet is image-formed on one side, and then the image is formed on the other side. By preventing the skew of the size of the paper on the paper re-feeding tray, a pair of skew prevention members are engaged with each side edge of the paper to better prevent the paper, and the paper can be rotated. Therefore, it is possible to provide a double-sided image forming apparatus that can easily form a high-quality double-sided image without causing an image position shift without hindering the conveyance of the paper when engaged with the paper. it can.

  A tray for stacking sheets on which images are to be formed, and a sheet that is displaceable in the width direction of the sheets stacked on the tray and for engaging the side edges of the sheets to position the sheets on the tray. A guide member and detection means for detecting the position of the guide member in the width direction of the paper, and the control means detects the skew feeding prevention member based on the position of the guide member detected by the detection means. If the paper is image-formed on one side and then the paper on which the image is formed on the other side, the skew on the refeed tray is shifted by the control means. The prevention member is prevented by being engaged with the side edge of the paper, and can be rotated so that the conveyance of the paper when engaged with the paper is not hindered. No, simple To provide a highly reliable double-sided image forming apparatus that can perform high-quality double-sided image formation and can reliably prevent problems such as jams caused by incorrect paper size settings. it can.

  Assuming that the skew prevention member has a shape whose diameter decreases upward, it is a sheet of paper on which an image is formed on one side, and then a sheet of paper on which an image is formed on the other side. The skew feeding on the refeed tray is prevented by engaging the skew prevention member with the side edge of the paper, and the rotation of the paper feeding tray prevents the paper from being transported when the paper is engaged. In addition, since the shape is configured such that the diameter decreases toward the upper side, the sheet can be received well and skewing can be prevented well. A double-sided image forming apparatus that can perform double-sided image formation can be provided.

  If the double-sided image forming apparatus is a stencil printing apparatus, in the stencil printing apparatus on the refeed tray of the paper printed on one side and then printed on the other side The skew that tends to occur is prevented, and the rotation of the skew prevention member does not hinder the conveyance of the paper when it is engaged with the paper. A double-sided image forming apparatus capable of performing quality double-sided printing can be provided.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention including examples will be described with reference to the drawings. In the present embodiment, components such as members and components having the same function, shape, and the like are described with the same reference numerals, and the description thereof will be omitted. In order to simplify the drawings and the description, even components that are to be represented in the drawings may be omitted as appropriate without being specifically described in the drawings.

  With reference to FIG. 1, the overall configuration of a double-sided stencil printing apparatus 200 as an example of a double-sided printing apparatus that is a double-sided image forming apparatus to which the present invention is applied will be described. As shown in FIG. 1, the double-sided stencil printing apparatus 200 is disposed at the upper left side of FIG. 1 and makes a master 8 wound in a roll shape, and is disposed at a substantially central portion in FIG. A plate cylinder 1 that winds a master 8 (hereinafter referred to as a “plate-making master 8”) around the outer peripheral surface, and an outer peripheral surface of the plate cylinder 1 can be freely contacted and separated. A printing unit 16 having a press roller 21 or the like as pressing means for pressing the paper 36, and a plate discharging unit that is disposed to face the plate making unit 15 with the plate cylinder 1 interposed therebetween, and peels and discharges the used master 8 on the plate cylinder 1. 17, and a sheet feeding unit 30 that is disposed below the plate discharging unit 17 and feeds a sheet 36 on a sheet feeding tray 35 serving as a sheet feeding table toward the printing unit 16. The printed paper 36 disposed below the plate making unit 15 is transferred to the plate cylinder 1. Peeling to have and a discharge portion 19 for discharging the sheet discharge tray 172 as a paper discharge tray.

  Further, the double-sided stencil printing apparatus 200 has a lower conveyance as a refeed storage unit that temporarily stores and stores the surface-printed paper 36 on which the printed image is formed on the surface that is one side of the printing unit 16. A sheet receiver 45 that is a refeed tray serving as an apparatus, a sheet holding unit 60 that conveys the surface-printed sheet 36 to the sheet receiver 45, and a peeling guide 46 as a guide unit that guides the surface-printed sheet to the sheet receiver 45. A sheet discharge conveyance unit 47 that constitutes a part of the sheet discharge unit 19 and a sheet refeed unit 49 that refeeds the surface-printed sheet 36 stored in the sheet receiver 45 toward the printing unit 16. ing.

  Further, as shown in FIG. 2, the double-sided stencil printing apparatus 200 includes a main body frame 130 as a printing apparatus main body in which a plate cylinder 1, a plate making unit 15, and a plate discharging unit 17 (both omitted in FIG. 2) are arranged. An image reading unit 18 that reads an image of a document 133 that is placed on the document tray 134 and is transported from a document receiving table 134 or an image such as a document (not shown) placed on a contact glass 135 as a reading unit, and a double-sided stencil printing apparatus FIG. 3 shows a control apparatus 100 as a control means shown in FIG. 3 that controls the overall operation of the apparatus 200 and a front surface of the double-sided stencil printing apparatus 200 for inputting predetermined information to the control apparatus 100. And an operation panel 173 as input means shown in FIG.

  The plate making unit 15 performs plate making on the master 8 and, as shown in FIG. 5, a first plate making image for surface printing along the rotation direction of the plate cylinder 1 (also the paper carrying direction X and the master carrying direction X1). A divided master-made master 8X having 8A (hereinafter referred to as “front-side plate-making image 8A”) and a second plate-making image 8B for back-side printing (hereinafter referred to as “back-side plate-making image 8B”), or the same figure As described above, the third plate-making image 8YA having an image amount area corresponding to two sides of the front-side plate-making image 8A and the back-side plate-making image 8B along the rotation direction of the plate cylinder 1 (hereinafter referred to as “one-side plate-making image 8YA”). Has a function and configuration for producing a pre-made master 8Y. The front plate-making image 8A is formed at a position corresponding to the surface region 1A shown in FIG. 1 when the divided plate-making master 8X is wound on the outer peripheral surface of the plate cylinder 1, and the back plate-making image 8B is the same as the back surface region 1B. And corresponding positions.

  In FIG. 1, FIG. 5, etc., the master-made master 8 </ b> Y is indicated with parentheses to distinguish it from the divided master-made master 8 </ b> X. In FIG. 5, the region range of the single-side plate-making image 8YA formed on the plate-making master 8Y is indicated by a two-dot chain line, and the boundary line of the same region range in the master transport direction X1 is the solid line of the front-side plate-making image 8A and the back-side plate-making image 8B. Because of the overlap, the area range is shown to be slightly larger. However, the area range of the single-side plate-making image 8YA is a front-side plate-making image 8A, a back-side plate-making image 8B, and an unfinished blank area that is located between them. This is the entire range including the plate making area 8C. In FIG. 5, the front plate making image 8A, the back plate making image 8B, the intermediate non-plate making region 8C, and the single-side plate making image 8YA are drawn out of scale, and in particular, the intermediate non-plate making region 8C is drawn in an exaggerated manner. It is.

  As illustrated in FIG. 1, the plate making unit 15 performs plate making by heating a master support member 8 c as a master support unit that supports the master 8 so that the master 8 can be fed out in the master transport direction X <b> 1, and according to image information. A thermal head 11, a platen roller 9 as a master conveying means for conveying the thermal head 11 while rotating the master 8 downstream in the master conveyance direction X 1 while pressing the master 8 against the thermal head 11, and a master conveyed by the platen roller 9 8 is applied between the platen roller 9 and the pair of conveying rollers 13 as a master conveying unit that conveys 8 to the downstream side in the master conveying direction X1 while applying an appropriate tension. The master plate 8 is conveyed by a cutter 12, a platen roller 9, and a conveying roller pair 13 that cut the master plate 8 to a predetermined length. The leading edge of the stencil 8 have; and a master guide plate 14 or the like for guiding the clamper 7 was expanded on the plate cylinder 1 as described below.

  The master 8 has a continuous sheet shape and is wound around a synthetic resin roll core 8b to form a master roll 8a. The roll core 8 b protrudes from both end faces of the master roll 8 a and is formed longer than the width of the master 8. In the master roll 8a, the roll cores 8b on both ends are rotatably supported by the master support member 8c in a counterclockwise direction, and are detachable from the master support member 8c. Both ends of the master support member 8c are attached and fixed to a pair of plate making side plates (not shown) disposed on the left and right sides of the plate making unit 15 along the master transport direction X1. Therefore, the master 8 is supported by the master support member 8c so that it can be fed out from the master roll 8a in the master transport direction X1.

  The master 8 has a laminated structure in which, for example, a thermoplastic resin film having a thickness of 1 to 5 μm and a porous support made of synthetic fiber or the like are bonded together. In addition, the master is not limited to this, and for example, a porous support made of Japanese paper fiber or a mixture of Japanese paper fiber and synthetic fiber and a thermoplastic resin film, or a so-called substantially thermoplastic material. A master made only of a resin film is also used.

  The thermal head 11 extends in parallel to the platen roller shaft of the platen roller 9 and the front side and the back side of the paper surface of FIG. 1, and is provided by a contact / separation mechanism including a cam and a spring member (not shown). The platen roller 9 can be contacted and separated via the master 8. The thermal head 11 is urged by the spring member so as to contact the platen roller 9. In the main scanning direction of the thermal head 11, a large number of heat generating elements (not shown) are disposed at portions that contact the platen roller 9 via the master 8. The thermal head 11 passes through an A / D conversion unit and an image signal processing unit (not shown) and the above-described heat generation based on a digital image signal processed and sent out by a plate making control device and a thermal head drive circuit (both not shown). By selectively heating the element, it has a well-known function as a plate making means for selectively heating, melting, punching and making the master 8.

  The platen roller 9 is formed integrally with the platen roller shaft through a metal cored bar. The platen roller 9 is rotatable clockwise because both end portions of the platen roller shaft are rotatably supported by the plate-making side plate pair. The platen roller 9 is connected to a master transport motor 10 as a master transport driving means via a rotation transmission member (not shown) such as a timing belt and a gear, and is thereby driven to rotate clockwise. The master transport motor 10 is composed of, for example, a stepping motor. As described above, when the platen roller 9 is driven to rotate clockwise by the master conveyance motor 10, the master 8 is pulled out from the master roll 8a.

  The conveying roller pair 13 is provided with an appropriate pressing force applied by an urging means such as a spring and pressed against each other, and both end portions of each roller shaft are rotatably supported by the plate making side plate pair. Thus, they can rotate in opposite directions. The conveyance roller pair 13 is set to rotate at a peripheral speed (conveyance speed) slightly faster than the peripheral speed (conveyance speed) of the platen roller 9 by the rotation transmission member including the master conveyance motor 10. Appropriate front tension is applied to the master 8 while sliding between the two. The drive system around the platen roller 9 and the conveyance roller pair 13 via the master conveyance motor 10 is substantially the same as the rotation transmission mechanism shown in FIG. 12 of Japanese Patent Laid-Open No. 11-77949 proposed by the applicant of the present application, for example. The mechanism is adopted.

The cutter 12 is a known guillotine type that includes a fixed blade 12b and a movable blade 12a. The cutter 12 is not limited to the guillotine type, and a rotary blade moving type in which the movable blade moves while rotating in the master width direction orthogonal to the master transport direction X1 may be used.
In the plate making section 15, the control target drive means of the plate making section 15 including the thermal head 11 driven by a thermal head drive circuit (not shown) and the master transport motor 10 is generally made as shown in FIG. Means 124 is used.

  The plate cylinder 1 has a two-layer structure of a porous and cylindrical support cylinder and a mesh screen (not shown) made of a resin or metal mesh wound around a plurality of layers so as to cover the outer periphery of the support cylinder. Consists of. The plate cylinder 1 is provided with a printable opening 1a (hereinafter sometimes referred to as an “image forming region”) in which a large number of ink-permeable holes are formed, a clamper 7 and the like, and is non-printable. Non-opening portions (hereinafter sometimes referred to as “non-image forming regions”) are formed along the rotation direction of the plate cylinder 1 indicated by arrows in FIG. The image forming area includes a first image area 1A (hereinafter referred to as “front surface area 1A”), an intermediate area 1C, and a second image area 1B (hereinafter referred to as “back surface area 1B”) in the plate cylinder 1 in FIG. ”) At least.

  The plate cylinder 1 is wound and fixed around an outer peripheral portion of an end plate flange (not shown), and is rotatably supported around a support shaft 5 that also serves as an ink pipe 5 described later. The size of the plate cylinder 1 is a size that can be printed on an A3 size paper 36 at the maximum during single-sided printing to obtain an A3 size printed matter, that is, a single master plate 8 of A3 size can be wound. The outer peripheral diameter is set to 180 mm (the outer peripheral length of the plate cylinder 1 is about 565 mm), and the width direction (rotation center axis direction) is set to 350 mm.

  The plate cylinder 1 is connected to a main motor 20 as a plate cylinder driving means via a drive transmission means such as a gear or a belt (not shown), and is driven to rotate in the direction of the arrow (clockwise) in FIG. The As the main motor 20, for example, a control DC motor is used. The output shaft of the main motor 20 is provided with an optical rotary encoder (not shown) and a plate cylinder sensor (not shown) that sandwiches the optical rotary encoder and generates a pulse by the cooperative action of the rotary encoder. Yes. This plate cylinder sensor is composed of a transmissive optical sensor, and is used for controlling the rotational speed (printing speed) of the plate cylinder 1 and determining the rotational position.

  Inside the plate cylinder 1 is rotatably supported by a side plate (not shown), and the rotational driving force of the main motor 20 is transmitted by a drive transmission means such as a gear (not shown) so as to be synchronized with the plate cylinder 1 in the figure. Between the ink roller 2 which is driven to rotate in the direction (clockwise) and contacts the inner peripheral surface of the plate cylinder 1 to supply ink, and the ink roller 2 which is arranged in parallel with the ink roller 2 with a slight gap. A doctor roller 3 for forming an ink reservoir 4 having a wedge-shaped cross section and an ink pipe 5 for supplying ink to the ink reservoir 4 are arranged. The ink roller 2, the doctor roller 3 and the ink pipe 5 constitute an ink supply means. In this embodiment, the ink supply means is a single one. The ink in the ink reservoir 4 is sucked by an ink pump (not shown) from an ink pack (not shown) provided outside the plate cylinder 1, supplied from the supply hole of the ink pipe 5, and kneaded. The ink in the ink reservoir 4 is supplied as a thin film on the outer peripheral surface of the ink roller 2 while being measured by the doctor roller 3, and further, the outer peripheral surface of the ink roller 2 comes into contact with the peripheral surface of the support cylinder in the plate cylinder 1. It is supplied to the opening 1 a portion of the plate cylinder 1.

  A part of the plate cylinder 1 on the outer peripheral surface of the non-opening portion includes a ferromagnetic stage 6 provided along one bus bar of the plate cylinder 1 and clamper shafts provided on both side ends of the stage 6. And a clamper 7 having a rubber magnet that is pivotably attached to the flat portion of the stage 6 and can be opened and closed. The clamper 7 is opened and closed at a predetermined position by an opening / closing device (not shown) provided on the main body frame side. The plate cylinder 1 is stopped in a state in which the clamper 7 is located almost directly as shown in FIG. The plate cylinder 1 is configured as a plate cylinder unit integrally formed with the ink pack, the ink pump, and the like, and is detachable in the axial direction of the ink pipe 5 with respect to the main body frame of the double-sided stencil printing apparatus 200. It has become.

  In FIG. 1, a sheet feed motor 37 and a registration motor of the sheet feeding unit 30 are detected by detecting the rotational position of the plate cylinder 1 on the end plate flange of the plate cylinder 1 on the back side of the paper surface and the main body frame side in the vicinity of the end plate flange. The component which gives the start (start) and trigger information to 41 is arranged. That is, on the outer wall of the end plate flange on the back side of the plate cylinder 1, a sheet feeding start light shielding plate and a resist start light shielding plate (not shown) are spaced apart from each other on the same circumference of the plate cylinder 1. Each is attached at a predetermined position, and a sheet feeding registration sensor (not shown) is attached to the main body frame side in the vicinity of the light shielding plates.

  In this embodiment, the home position (initial position) of the plate cylinder 1 receives the front end of the divided plate-making master 8X and the plate-making master 8Y conveyed from the plate-making unit 15 with the clamper 7 positioned substantially directly above. It is set to the same position as the plate feeding standby position, which is the holding position. A non-illustrated home position light shielding plate for detecting the home position of the plate cylinder 1 is attached to a predetermined position of the outer wall of the end plate flange on the back side of the plate cylinder 1. A home position sensor (not shown) is attached to the main body frame side in the vicinity of the home position light shielding plate so as to face the home position light shielding plate of the plate cylinder 1 and sandwich it. The home position sensor is a transmissive optical sensor. In FIG. 3, the plate cylinder sensor, the paper feed registration sensor, and the home position sensor are collectively referred to as a plate cylinder position detection sensor 29 as a plate cylinder position detection unit that detects the rotational position of the plate cylinder 1.

A single press roller 21 is disposed near the lower part of the outer peripheral surface of the plate cylinder 1 facing the ink roller 2. The press roller 21 is configured by integrally fixing an elastic body to a metal press roller shaft 21 a and is provided to extend in the axial direction of the plate cylinder 1. The press roller 21 is formed so that its lateral width is the same as that of the master 8 that covers the opening 1a of the plate cylinder 1 or a length that is slightly wider than that. The press roller 21 has a pair of printing pressure arms 22 (not shown on the front side of the paper surface) as pressing means support members disposed on the front side and the back side of the paper surface via both ends of the press roller shaft 21a. ) Is supported rotatably.
Each printing pressure arm 22 is integrated by an arm shaft 22a and a connection reinforcing member (not shown). The arm shaft 22a is supported between a pair of casing side plates (not shown) fixed on the main body frame 130 side via a bearing (not shown) so as to be rotatable by a predetermined angle.

  The press roller 21 is formed of an elastic material having oil resistance, such as nitrile rubber (NBR) or silicone rubber (Q), and at least the outer peripheral surface of the rubber is prevented from being stained with an offset printing device or the like. The glass beads used in the coating are uniformly arranged, or the outer peripheral surface of the press roller 21 is smooth with a film having ink repellency and oil resistance such as fluoro rubber (FKM) and polytetrafluoroethylene resin. It may be coated on the surface. As a result, the contamination due to swelling and ink adhesion caused by contact with the ink on the printed image surface side of the surface-printed paper 36 is minimized when contacting the divided master-making master 8X or the master-making master 8Y on the plate cylinder 1. It is made to become.

  The press roller 21 is printed on the unprinted paper 36 or the surface of the divided master-making master 8X or the master-making master 8Y on the plate cylinder 1 by a printing pressure range changing means 28 and each printing pressure arm 22 shown in FIG. 1 is configured to be displaceable between a printing position shown in FIG. 1 where the paper 36 is pressed and a non-printing position (which is also an initial position) shown in FIG. 6 away from the printing position.

  The press roller 21 is rotationally driven by a press roller rotation driving unit as a pressing unit driving unit (not shown). The press roller rotation drive means is a press roller drive motor 55 shown in FIG. 3 as drive means for driving the press roller 21 in a direction opposite to the rotation direction of the plate cylinder 1 at a circumferential speed substantially the same as the circumferential speed of the plate cylinder 1. And a driving force transmitting means for transmitting the rotational driving force of the press roller driving motor 55 to the press roller 21.

  The press roller 21 is a press roller drive motor in accordance with the timing when the unprinted paper 36, the front surface printed paper 36, or the single-side printed paper 36 is pressed against the divided master 8X or the master 8Y on the plate cylinder 1. 55 is rotationally driven. The operation of the press roller drive motor 55 is controlled by the control device 100 shown in FIG. Since the press roller 21 is rotationally driven by the press roller drive motor 55 at a substantially same peripheral speed as the peripheral speed of the plate cylinder 1, it is possible to obtain a good printed matter with no print image positional deviation.

  In addition to the press roller 21, a refeed resist roller 51 as a refeed resist member, a roller guide plate 50 as a feed guide member, and the like are disposed between the printing pressure arms 22. The re-feed resist roller 51 holds the front end of the surface-printed paper 36 stored in the paper receiver 45 between the press roller 21 and the press roller 21 when the press roller 21 contacts the plate cylinder 1. It has a function of transporting the front end of the surface-printed paper 36 to the plate cylinder 1 at a predetermined timing by rotation. The re-feeding registration roller 51 is composed of a plurality of rollers divided in a skewered manner, and is formed integrally with the shaft 51a. The re-feeding registration roller 51 is disposed on the lower side of the press roller 21 with its outer peripheral surface being in pressure contact with the outer peripheral surface of the press roller 21, and both end portions of the shaft 51 a are freely rotatable between the printing pressure arms 22. As a result, the rotational force of the press roller 21 is received and the driven roller rotates following the direction opposite to the rotational direction of the press roller 21.

The roller guide plate 50 has a function of guiding the surface-printed paper 36 conveyed by the rotational force of the press roller 21 toward the plate cylinder 1 while abutting on the outer peripheral surface of the press roller 21. The roller guide plate 50 has a curved partial cylindrical shape centered on the press roller shaft 21a in order to guide the surface-printed paper 36 along the outer peripheral surface of the press roller 21. Are fixed between the printing pressure arms 22. The guide surface side of the surface-printed paper 36 in the roller guide plate 50 is coated with a film having a low coefficient of friction with respect to the surface-printed paper 36 and having ink repellency and oil resistance such as polytetrafluoroethylene resin. ing.
The re-feeding means 49 holds the surface-printed paper 36 on its outer peripheral surface and rotates and conveys it to the plate cylinder 1, a re-feeding registration roller 51, a roller guide plate 50, and FIG. It is mainly composed of a re-feed sensor 52 as a surface printed paper detection means.

Next, the configuration around the printing pressure range varying means 28 that determines the printing pressure range of the press roller 21 will be described in detail. In this embodiment, as shown in FIGS. 1 and 5, as a first printing pressure range pattern that applies printing pressure only to the surface area 1 </ b> A corresponding to the surface plate-making image 8 </ b> A in the divided plate-making master 8 </ b> X on the plate cylinder 1. And a printing pressure range pattern II as a second printing pressure range pattern that applies printing pressure only to the back surface area 1B corresponding to the back plate making image 8B in the divided plate-making master 8X on the plate cylinder 1. And a printing pressure range pattern as a third printing pressure range pattern for applying a printing pressure from the front surface region 1A to the back surface region 1B corresponding to the single-side plate-making image 8YA in the plate-making master 8Y on the plate cylinder 1. One of at least three printing pressure range patterns with III can be selectively switched.
The printing pressure range variable means 28 has a configuration / function for displacing the press roller 21 between a printing position and a non-printing position, and selectively switches one of these three printing pressure range patterns. . The printing pressure range varying means 28 may also be called a press roller contacting / separating mechanism as pressing means contacting / separating means.

The printing pressure range varying means 28 includes an arm shaft 22a, printing arm pairs 22, 22, a pair of cam followers (not shown), a pair of printing springs (not shown), a plurality of sets of printing pressure cams (not shown), solenoids (not shown), and the like. This is a known configuration.
Each cam follower is rotatably held by each printing pressure arm 22. Each printing spring is locked between each printing arm 22 and a housing side plate (not shown), and always presses the press roller 21 in a direction in which it is pressed against the outer peripheral surface of the plate cylinder 1. Each printing pressure cam is rotatably supported on the casing side plate near each cam follower, and is connected to the main motor 20 via a drive transmission means such as a belt or a gear (not shown), and is synchronized with the rotation of the plate cylinder 1. And is designed to rotate. The cam follower is urged by a printing pressure spring 25 so as to always come into contact with the printing pressure cam.

  The printing cam is composed of, for example, a plate cam in which a small-diameter portion (concave portion) and a large-diameter portion (convex portion) are formed. The shape is different. The large diameter portion of the printing pressure cam is pressed against the cam follower against the urging force of the printing pressure spring, so that the printing pressure by the press roller 21 is turned off / released. A printing pressure cam that engages with the cam follower is switched by a solenoid or the like according to the three printing pressure range patterns.

  FIG. 5 is an expanded view of the printing pressure range of the press roller 21 for easy understanding. In FIG. 5, an area portion of the front plate-making image 8A and an area portion of the back-side plate-making image 8B are formed on the divided plate-making master 8X wound around the opening 1a on the plate cylinder 1 (not shown in FIG. 5). In addition, there is an unfinished blank intermediate unmade region 8C between them. Here, the leading side of the divided plate-making master 8X, which is also called the leading edge blank portion sandwiched and fixed by the clamper 7 of the plate cylinder 1 (not shown in FIG. 5), is the left end side.

  The printing pressure range pattern for normal printing including single-sided printing is as shown in III. That is, the printing pressure range pattern III is applied to one side of the prepressed master 8Y by applying a printing pressure from the area portion of the front plate making image 8A to the area portion of the back plate making image 8B through the intermediate non-plate making area 8C. The printing cam is rotated so that the small diameter portion of the predetermined printing cam faces the cam follower so that the paper 36 is continuously pressed against the plate-making image 8YA.

  At the time of surface printing, the printing pressure range pattern I is printed, and the printing is performed so that the small diameter portion of a predetermined printing pressure cam faces the cam follower so as to be printed corresponding to the area portion of the surface plate-making image 8A. The pressure cam is driven to rotate, and then the solenoid is controlled to be turned on / off so that the large diameter portion of the predetermined printing pressure cam abuts the cam follower so that the printing pressure is released in the intermediate unmade region 8C. .

  At the time of printing on the back side, the printing pressure range pattern II is obtained, and the large-diameter portion of a predetermined printing pressure cam abuts on the cam follower so that the printing pressure is released in the region of the first front plate-making image 8A. The solenoid is controlled to be turned on / off, and then the printing cam is rotationally driven so that the small diameter portion of the predetermined printing pressure cam faces the cam follower.

  The above can be summarized as follows. That is, a printing pressure range pattern I as a first printing pressure range pattern that applies printing pressure only to the surface region 1A corresponding to the surface plate-making image 8A in the divided plate-making master 8X on the plate cylinder 1, and on the plate cylinder 1 In the divided plate-making master 8X, a printing pressure range pattern II as a second printing pressure range pattern that applies a printing pressure only to the back surface area 1B corresponding to the back surface plate-making image 8B, and the back surface area 1B continuously from the front surface area 1A. One of at least three printing pressure range patterns and a printing pressure range pattern III as a third printing pressure range pattern for applying printing pressure can be selectively switched. The mechanism for selectively switching one of these three printing pressure range patterns is the printing pressure range variable means 28 described above.

  As shown in FIG. 1, the paper discharge conveying means 47 is disposed on the left side of the plate cylinder 1. The paper discharge conveying means 47 includes a paper discharge roller rear 84 as a drive roller integrally provided on a drive shaft 85 rotatably supported between a pair of casing side plates (not shown), and a paper more than the drive shaft 85. A discharge roller front 86 as a driven roller integrally provided on a driven shaft 87 disposed on the upstream side in the transport direction X and in the vicinity of the peeling guide 46, a discharge roller rear 84, and a discharge roller front 86. Paper 36 which has been surface-printed by being wound and stretched between the two, and paper 36 which has been printed on both sides which has been ejected and conveyed from a nip portion as an image forming unit which is a press-contact portion between the plate cylinder 1 and the press roller 21 A discharge belt 88 formed with a plurality of holes for air suction as an endless belt that holds and conveys any one of the finished sheets 36, and a driving force transmission means such as a gear or a belt on the drive shaft 85 Are connected via A belt driving motor 90 as a belt driving means for rotating the paper discharge belt 88 through the rotational drive of the rear 84, the surface printed paper 36 discharged and conveyed from the nip portion toward the paper discharge belt 88, both sides Mainly from a single suction fan 89 for sucking and holding either the printed paper 36 or the single-side printed paper 36 on the upper surface of the paper discharge belt 88 by sucking air from the plurality of holes 88. It is configured.

The paper discharge roller rear 84 and the paper discharge roller front 86 are divided into skewers and formed of toothed rollers, and are formed of a high friction material having oil resistance (ink corrosion resistance) such as nitrile rubber (NBR). However, a resin or the like may be used as long as the material has such properties. The paper discharge belt 88 is formed of a toothed belt, and is wound around and stretched between a paper discharge roller rear 84 and a paper discharge roller front 86 each of which is divided into a plurality of skewers. The discharge belt 88 is formed of, for example, nitrile rubber (NBR) or silicone rubber (Q), which is an oil-resistant elastic body, in order to be held and conveyed in contact with the printed image surface side of the surface-printed paper 36. At least the outer peripheral surface of the rubber is smoothly coated with a film having ink repellency and oil resistance such as fluoro rubber (FKM) and polytetrafluoroethylene resin. The suction fan 89 incorporates a fan drive motor as fan drive means. Hereinafter, for the sake of simplicity, the “fan driving motor” is sometimes simply referred to as “suction fan 89”.
The paper discharge belt 88 is rotated by the operation of a belt drive motor 90 based on a command signal from the control device 100.

  The peeling guide 46 is disposed on the upstream side in the paper transport direction X from the paper discharge belt 88, and rotates about a predetermined angle about a shaft 46a on the downstream side in the paper transport direction X. The peeling guide 46 has a thin plate shape with a sharp tip. The peeling guide 46 is rotated by driving means such as a solenoid and a stepping motor (not shown), and when the press roller 21 occupies the printing position, the tip rotates toward the plate cylinder 1 side. When the press roller 21 occupies the non-printing position, the tip rotates toward the press roller 21 side. The peeling guide 46 also serves as a peeling means for peeling the surface-printed paper 36 printed at the nip portion from the plate cylinder 1 when the tip rotates toward the plate cylinder 1 side.

  The plate removal unit 17 includes an upper plate removal member 160, a lower plate removal member 161, a plate removal box 162, a compression plate 163, and the like. The upper plate removal member 160 includes a driving roller 164, a driven roller 165, an endless belt 166, and the like. The drive roller 164 is rotationally driven in the clockwise direction of FIG. 1 by a plate discharge driving means 126 (see FIG. 3) including a plate discharge motor (not shown), whereby the endless belt 166 moves in the arrow direction in FIG. The lower plate removal member 161 includes a driving roller 167, a driven roller 168, an endless belt 169, and the like. The driving roller 167 is driven to rotate in the clockwise direction in FIG. 1 by transmitting the driving force of the above-mentioned plate discharging motor that rotates the driving roller 164 by driving force transmitting means (not shown) such as a gear or a belt. The endless belt 169 moves in the direction of the arrow in FIG. Further, the lower plate discharging member 161 is movably provided by a moving unit (not shown) included in the plate discharging driving unit 126, and an endless belt 169 positioned on the outer peripheral surface of the driven roller 168 and the position shown in the figure is the plate cylinder 1. And a position that abuts on the outer peripheral surface.

  The plate removal box 162 stores a used master therein and is detachably attached to the main body frame 130. The compression plate 163 is supported by the main body frame 130 so as to be movable up and down so that the used master carried by the upper plate removal member 160 and the lower plate removal member 161 is pushed into the plate release box 162. It is moved up and down by lifting means (not shown) including the lifting motor included. The plate removal unit 17 includes an upper plate removal member 160, a lower plate removal member 161, a plate removal box 162, a compression plate 163, and the like. The upper plate removal member 160 includes a driving roller 164, a driven roller 165, an endless belt 166, and the like. The drive roller 164 is driven to rotate counterclockwise in FIG. 1 by a plate discharge driving means 126 (see FIG. 3) including a plate discharge motor, whereby the endless belt 166 moves in the arrow direction in FIG. The lower plate removal member 161 includes a driving roller 167, a driven roller 168, an endless belt 169, and the like. The driving roller 167 is rotationally driven in the clockwise direction in FIG. 1 by transmitting the driving force of the above-described plate discharge driving means 126 that rotationally drives the driving roller 164 by driving force transmission means (not shown) such as a gear or a belt. As a result, the endless belt 169 moves in the direction of the arrow in FIG. Further, the lower plate discharging member 161 is movably provided by a moving unit (not shown) included in the plate discharging driving unit 126, and an endless belt 169 positioned on the outer peripheral surface of the driven roller 168 and the position shown in the figure is the plate cylinder 1. And a position that abuts on the outer peripheral surface.

  The plate removal box 162 stores a used master therein and is detachably attached to the main body frame 130 shown in FIG. The compression plate 163 is supported by the main body frame 130 so as to be movable up and down so that the used master carried by the upper plate removal member 160 and the lower plate removal member 161 is pushed into the plate release box 162. It is moved up and down by lifting means (not shown) including the lifting motor included. In FIG. 3, the control target driving means of the plate discharging unit 17 including the plate discharging motor 17, the moving unit, and the lifting motor is collectively referred to as a plate discharging driving unit 126.

  As shown in FIG. 1 or FIG. 7, the paper feed unit 30 includes a paper feed tray 35 as a tray that can be lifted up and down by stacking paper 36 on which image formation, that is, printing, can be lifted, and a plate cylinder 1. A registration roller pair 31 serving as registration means for feeding the paper 36 at a timing described later between the outer peripheral surface and the press roller 21, and a nip between the registration roller pair 31 in contact with the paper 36 on the paper feed tray 35. A sheet feeding roller 33 and a separating member 34 as sheet feeding means for separating and transporting the sheets 36 one by one toward the section; a sheet size detecting means 109 for detecting the sheet size of the sheet 36, and the like. .

  The paper feed tray 35 is provided with a drive device (not shown) including a paper feed tray lifting / lowering motor (not shown) as a lifting / lowering means (not shown) for moving the paper feeding tray 35 up and down. The upper level always comes into contact with the paper feed roller 33 with a predetermined pressing force (pressing force capable of transporting the paper 36), that is, in contact with the increase / decrease of the paper 36 with a pressing force within a range in which the paper 36 can be transported. It is moved up and down while maintaining the state. The paper feed tray 35 has a structure that can use many paper types and paper sizes, and a stencil printing apparatus capable of stacking 500 sheets or more of paper with a paper loading capacity of, for example, paper size A3 (vertical) or A4. It has a structure suitable for.

  The paper size detection means 109 is disposed so as to be displaceable in the paper width direction Y, and is a pair of side fences 110a and 110b as guide members for engaging and aligning with each side edge of the paper 36 according to the paper size. A pinion 116 rotatably attached to and supported by a non-illustrated immovable member disposed at the lower portion of the paper feed tray 35, and a rack portion 115 formed at the lower edge of the side fence 110a and meshing with the pinion 116. A rack portion 114 formed on the lower edge portion of the side fence 110b and meshing with the pinion 116 so as to face the rack portion 115; and a lower edge portion facing the rack portion 114 of the side fence 110b so as to protrude downward and bend appropriately. And a shielding portion 114a having a plurality of notches cut out at intervals of.

The paper size detection means 109 is also fixed to the stationary member of the paper feed tray 35 at an appropriate interval and is selectively engaged with the blocking portions 114a (two in this case), the horizontal size detection sensors 118a, 118b and a plurality of (here, three) vertical size detection sensors 119a, 119b, and 119c fixed at an appropriate interval in the paper feed direction X of the stationary member of the paper feed tray 35. Yes.
The paper size detection means 109 detects the paper size of the paper 36 in conjunction with the movement of the side fence pair 110a, 110b in the paper width direction Y.

  Each of the lateral size detection sensors 118a and 118b is a transmissive optical sensor having a light emitting portion and a light receiving portion, and selectively engages with the blocking portion 114a to thereby make the length in the paper width direction Y of the paper 36.・ Detect the size. Accordingly, each of the lateral size detection sensors 118a and 118b has a function as detection means for detecting the position of the side fences 110a and 110b in the paper width direction Y of the paper 36.

  The vertical size detection sensors 119a, 119b, and 119c are reflection type optical sensors. The vertical size detection sensors 119a, 119b, and 119c detect the length and size of the paper 36 in the paper feeding direction X. The horizontal size detection sensors 118a and 118b and the vertical size detection sensors 119a, 119b, and 119c are collectively referred to as a paper size detection sensor 117.

  The paper size detection sensor 117 is electrically connected to the control device 100 to be described later, and the CPU 101 of the control device 100 makes a determination by combining the size signal data detected by the paper size detection sensor 117, whereby the paper 36. This determines the paper size. Therefore, it can be said that the entire sheet size detection sensor 117 has a function as a detection unit that detects the positions of the side fences 110a and 110b in the sheet width direction Y of the sheet 36. The paper size detection sensor 117 has a function as a paper size detection unit that detects the paper size of the paper 36, and the vertical size detection sensor 119 a also has a function as a paper presence / absence detection unit that detects the presence / absence of the paper 36.

  For the sake of simplicity, two horizontal size detection sensors for detecting the length and size of the paper 36 in the paper width direction Y and two vertical size detection sensors for detecting the size of the paper 36 in the paper feeding direction X are respectively used for simplicity of explanation. However, it may be arranged more than this so that more sizes can be detected. The paper size detection method is not limited to the method described above, and other methods, for example, the slider slides in conjunction with a paper feed side plate (side fence) and is arranged according to the paper size. It may be one that detects by contacting / connecting with each terminal of the paper size detection plate, and these are used as detection means for detecting the position of the side fences 110a, 110b of the paper 36 in the paper width direction Y. Can do.

  The paper feed roller 33 is formed integrally with a metal paper feed roller shaft 33a, and one end of the paper feed roller shaft 33a is rotatably supported by the casing side plate. The surface of the paper feed roller 33 is formed of at least a high friction resistance member such as rubber. The paper feed roller shaft 33a rotates the paper feed roller 33 so as to transport the paper 36 only in the paper transport direction X, that is, through a one-way clutch (not shown) for rotating only in the clockwise direction. 37. The separation member 34 has a member called a separation pad that is made of rubber or resin having a high friction coefficient with respect to the paper 36 and that can contact the paper feed roller 33. This separation pad is urged in a direction to be pressed against the paper feed roller 33 by a compression spring (not shown) as urging means.

The paper feed motor 37 is composed of, for example, a stepping motor as a motor driven by pulse input.
A registration motor 41 is connected to the shaft 31 c of the lower roller constituting the registration roller pair 31. The registration motor 41 is composed of, for example, a stepping motor as a motor driven by pulse input.

  In FIG. 1, the leading and trailing ends of the sheet 36 fed from the registration roller pair 31 are detected in the sheet conveyance path XA from the nip portion between the plate cylinder 1 and the press roller 21 to the nip portion of the registration roller pair 31. A paper detection sensor 32 as a paper detection means is provided. In the paper detection sensor 32, the paper 36 stays in the paper transport path XA on the upstream side of the arrangement position of the paper detection sensor 32 (position where the leading edge of the paper 36 can be detected) (jamming or the like occurs). It also has a function to detect. The paper detection sensor 32 is a reflective optical sensor having a light emitting unit and a light receiving unit.

  The control target drive means of the paper feed unit 30 including the paper feed tray lifting / lowering motor, the paper feed motor 37, and the registration motor 41 of the paper feed unit 30 is generally shown as a paper feed drive means 125 in FIG. The paper feed driving means for rotationally driving the paper feed roller 33 is not limited to the paper feed motor 37 and the like, and the rotational driving force from the main motor 20 is supplied by a driving force transmitting means (not shown) such as a gear or a cam. It may be configured to be driven to rotate at a predetermined timing synchronized with the plate cylinder 1. Similarly, the registration driving means for rotationally driving the registration roller pair 31 is not limited to the registration motor 41 or the like, and the rotational driving force from the main motor 20 is transmitted by a driving force transmission means (not shown) such as a gear or a cam. The sheet 36 may be fed at a predetermined timing toward the nip portion between the plate cylinder 1 and the press roller 21.

  As shown in FIG. 1, the paper discharge unit 19 is provided so as to be close to the outer peripheral surface of the plate cylinder 1, and a peeling claw 170 for peeling the single-side printed paper 36 from the plate-making master 8 </ b> Y on the plate cylinder 1. A separation fan 171 for blowing air between the front end portion of the single-sided printed paper 36 separated by the claw 170 and the plate cylinder 1 to assist the separation action by the separation claw 170, a paper discharge conveying means 47, a paper discharge Mainly composed of a tray 172.

  The peeling claw 170 is provided in the vicinity of the downstream in the printing nip portion formed by the press roller 21 being pressed against the outer peripheral surface of the plate cylinder 1. The peeling claw 170 is placed on the plate cylinder 1 in the vicinity of the outer peripheral surface of the plate cylinder 1 by a peeling claw displacing means (not shown) having a cam and a spring that are driven to rotate in synchronization with the rotation of the plate cylinder 1. A separation position for forcibly separating the single-sided printed paper 36 from the pre-printed master 8Y, and a non-peeling position for avoiding contact with the clamper 7 arrangement portion protruding from the outer peripheral surface of the plate cylinder 1 apart from the separation position. It is configured to be freely displaceable between. The peeling fan 171 has a built-in fan drive motor that rotationally drives the peeling fan.

  As shown in FIG. 2, the image reading unit 18 includes the above-described document receiving plate 134 on which a plurality of documents 133 are stacked, a contact glass 135 as a reading unit on which the document 133 is placed, and a document that conveys the document 133. A pair of transport rollers 136 and a document transport roller 137, guide plates 138 and 139 for guiding the transported document 133, a plurality of document transport belts 140 that transport the document 133 along the contact glass 135, and the read document 133 A document tray 141, a pressure plate 142 that supports each member except the contact glass 135, and is provided so as to be able to contact / separate / open / close with respect to the contact glass 135, and scans and reads an image of the document 133 while illuminating it. Reflection mirrors 143 and 144 and a fluorescent lamp 145 for focusing the reflected light of the scanned and read image A lens 146, and a like image sensor 147 having a CCD (charge coupled device) or the like for processing the reflected light of the focused image.

  In the above configuration, the original 133 is placed on the contact glass 135 (reading unit) by the original receiving tray 134, the original conveying roller pair 136, the original conveying roller 137, the guide plates 138 and 139, the original conveying belt 140, and the original tray 141. An automatic document feeder (hereinafter referred to as “ADF”) 148 is configured as an automatic document feeder that feeds sheets one by one. Further, a scanner device 132 as a document reading unit that reads an image of the document 133 on the contact glass 135 (reading unit) by the contact glass 135, the reflecting mirrors 143 and 144, the fluorescent lamp 145, the lens 146, and the image sensor 147, Each of the reflecting mirrors 143 and 144, the fluorescent lamp 145, and the lens 146 constitutes a document scanning optical system. The document transport roller pair 136, the document transport roller 137, and the document transport belt 140 are driven by a document transport motor (not shown). The scanner device 132 is provided with a scanner motor (not shown) that drives the scanner device 132.

The image sensor 147 performs photoelectric conversion corresponding to the received reflected light, and inputs an image signal obtained thereby to the A / D conversion unit.
In the vicinity of the lower part of the contact glass 135, a document vertical size detection sensor 149a that detects the length of the document in the transport direction (left-right direction) in the view of the document 133 to be transported or the document not shown placed on the contact glass 135. 149b, and a document lateral size detection sensor (not shown) for detecting the length of the front side and the back side of the paper in the drawing of the document 133 (not shown) placed on the document 133 or the contact glass 135 to be conveyed. . The document vertical size detection sensors 149a and 149b and the document horizontal size detection sensor detect the sizes of the document 133 to be conveyed or the document (not shown) placed on the contact glass 135. These are hereinafter referred to as the document size detection sensor 149. Collectively. The original size detection sensors 149a and 149b of the original size detection sensor 149 and the original horizontal size detection sensor are both reflective optical sensors, and the outline and size of the original 133 and the original are determined depending on the amount of reflection on the contact glass 135. The presence or absence of 133 is detected. A signal from the document size detection sensor 149 is input to the control device 100. Based on the signal from the document size detection sensor 149, the control device 100 determines and recognizes the document size (when it is the same size, it is also the size of the plate-making image to be made / formed on the master 8). A document detection sensor 131 that detects the document 133 remaining on the document tray 134 is disposed below the document tray 134. The document detection sensor 131 outputs a signal to the control device 100 when the document 133 on the document tray 134 is exhausted. The control target drive unit of the paper discharge unit 19 including the scanner motor and the document transport motor of the image reading unit 18 is generally indicated as a read drive unit 128 in FIG.

As shown in FIG. 4, the operation panel 173 is for instructing the double-sided stencil printing apparatus 200 to perform a predetermined operation or the like, and is disposed in the vicinity of the image reading unit 18 shown in FIG. ing.
The operation panel 173 has a plate making start key 174, a printing start key 175, a test printing key 176, a continuous key 177, a clear / stop key 178, a numeric key 179, an enter key 180, a program key 181, a mode clear key 182 on the upper surface of the operation panel 173. Speed setting key 183, four-direction key 184, paper size setting key 185, double-sided printing key 187, single-sided printing key 188, display device 189 composed of 7-segment LED (light emitting diode), display device 190 composed of LCD (liquid crystal display device) Etc.

  The plate-making start key 174 is pressed when the double-sided stencil printing apparatus 200 performs a plate-making operation. When the plate-making start key 174 is pressed, a plate-making operation is performed after a plate-discharging operation and a document reading operation are performed. A printing operation is performed. After the printing operation, when the continuous mode to be described later is not set, the double-sided stencil printing apparatus 200 enters a print standby state. The print start key 175 is pressed when the double-sided stencil printing apparatus 200 performs a printing operation when the continuous mode is not set, and printing is performed after the double-sided stencil printing apparatus 200 enters a print standby state and various printing conditions are set. When the start key 175 is pressed, a printing operation is performed. The test printing key 176 is pressed when the double-sided stencil printing apparatus 200 performs a test printing. When various conditions are set and the test printing key 176 is pressed to set a test printing, that is, a test print, only one test print is made. Printing is to be performed. The continuous key 177 is pressed before pressing the plate making start key 174 when performing the plate making operation and the printing operation continuously. After pressing the continuous key 177, the printing plate start key 174 is pressed after the printing conditions are input. Then, the printing operation is performed following the plate discharging operation, the document reading operation, and the plate making operation.

  The clear / stop key 178 is pressed when the operation of the double-sided stencil printing apparatus 200 is stopped or when the number is cleared. The numeric keypad 179 is used for numerical input. The enter key 180 is pressed when setting a numerical value or the like during various settings, and the program key 181 is pressed when registering or calling a frequently performed operation. The mode clear key 182 clears various modes. Press to return to the initial state. The print speed setting key 183 is pressed when setting the print speed prior to the printing operation, and when it is desired to obtain a darker image or when the ambient temperature is low, the print speed is slow and a lighter image is desired. Or, when the ambient temperature is high, the printing speed is set fast. The four-way key 184 has an up key 184a, a down key 184b, a left key 184c, and a right key 184d. When adjusting the image position during image editing, or when selecting numerical values or items at various settings, etc. Pressed. The paper size setting key 185 is pressed when an arbitrary paper size is input, and the paper size input with the paper size setting key 185 has priority over the paper size detected by the paper size detection sensor 73.

  The double-sided printing key 187 is pressed before the plate making start key 174 is pressed when the double-sided stencil printing apparatus 200 performs the double-sided printing operation. When the double-sided printing key 187 is pressed, the LED 187a disposed in the vicinity thereof lights up. Is displayed indicating that the duplex printing mode is set. Similarly to the double-sided printing key 187, the single-sided printing key 188 is pressed before pressing the plate making start key 184 when the double-sided stencil printing apparatus 200 performs a single-sided printing operation. The arranged LED 188a is turned on to indicate that the single-sided printing mode is set. In the double-sided stencil printing apparatus 200, the LED 188a is lit in an initial state after turning on a power switch (not shown), and the single-sided printing mode is set.

  The display device 189 mainly displays numbers such as the number of printed sheets. The display device 190 has a hierarchical display structure. By selecting and pressing selection setting keys 190a, 190b, 190c, and 190d provided below the display device 190, various modes such as scaling and position adjustment can be entered. It can be changed and set in each mode. For example, it can be set whether or not to specify the continuous mode. When the continuous mode is set, the printing operation is started without entering the printing standby state after the printing operation. It is also possible to set whether or not to perform image position adjustment. When the image position adjustment is set, the test print is performed when the test print is set, and the four-way key 184 is pressed immediately after the start of the print operation when the test print is set not to be performed. The printing position can be adjusted by using this. The display device 190 displays the state of the double-sided stencil printing device 200 such as “can be made and printed” as shown in the figure, warnings such as plate-making or discharge jam, paper feed or paper discharge jam, paper, An instruction to supply a master, ink, etc. is also displayed.

Control according to each mode and each setting is performed by the control device 100 described later.
In addition to the operation panel 173, external input means such as a personal computer can be connected to the double-sided stencil printing apparatus 200 as input means for inputting predetermined information to the control apparatus 100. When such an input means is connected, it is possible to input all the information input through the operation panel 173 described above. Further, it is also possible to input image data to be formed, that is, image data to be printed by such input means. Note that the operation panel 173 is not necessarily required when such input means can be connected to the double-sided stencil printing apparatus 200.

  The main control configuration of the double-sided stencil printing apparatus 200 will be described with reference to FIG. The control device 100 has a function and configuration as a control unit that mainly controls a document reading operation, a plate making operation, a paper feeding operation, and a printing operation of the double-sided stencil printing apparatus 200. The control device 100 includes a CPU 101 (central processing unit), an I / O (input / output) port (not shown), a ROM 102 (read-only storage device), a RAM 103 (read / write storage device), a timer with a battery (not shown), and the like. And a microcomputer having a configuration in which they are connected by a signal bus (not shown).

  As shown in FIG. 1, the control device 100 is provided in a control board arrangement section in the main body frame 130 shown in FIG. 2. The CPU 101 of the control device 100 (hereinafter, sometimes simply referred to as “control device 100” for the sake of simplicity) receives various signals from the operation panel 173 and the above-described various sensors provided on the main body frame 130. Based on the detection signal and the operation program called from the ROM 102, the plate cylinder driving means 129 of the printing unit 16, the plate making unit 15, the paper feeding unit 30, the plate discharging unit 17, the paper discharge unit 19, and the image reading unit 18 are provided. The operation of the suction fan 89, the belt drive motor 90, and the swing motor 96 provided in each drive means, the press roller drive motor 55, and the paper discharge transport means 47 is controlled to control the operation of the entire duplex stencil printing apparatus 200. To do. The control device 100 also grasps the rotational position of the plate cylinder 1 based on various plate cylinder position signals from the plate cylinder position detection sensor 29 generally shown in FIG.

  The ROM 102 stores an operation program for the entire duplex stencil printing apparatus 200, necessary data, and the like, and this operation program is appropriately called by the CPU 101. The RAM 103 has a function of temporarily storing the calculation result of the CPU 101, a function of storing data signals and ON / OFF signals set and input from various keys and various sensors on the operation panel 173 as needed.

  As shown in FIG. 1, the paper receiver 45 is disposed below the paper discharge conveying means 47. The paper receiver 45 is disposed in the vicinity of the conveyance roller rear 154 integrally provided on the drive shaft 155 that is rotatably supported between the pair of casing side plates and the re-feeding registration roller 51. Further, a front roller 156 as a driven roller provided integrally with the driven shaft 157, and a rear roller 154 and a front roller 156 are wound and stretched so as to hold and convey the surface-printed paper 36. A conveying belt 158 formed with a plurality of holes (not shown) for sucking air as an endless belt, and connected to the drive shaft 155 via a driving force transmission means such as a gear or a belt, via the rotational drive of the rear 154 of the conveying roller. A belt driving motor 150 as a belt driving means for rotationally driving the conveying belt 158 and the surface-printed paper 36 by sucking air from a plurality of holes to convey the conveying belt 15. And a suction fan 159 for causing the suction-held on the upper surface.

  The sheet receiver 45 also engages with the surface-printed sheet 36 to prevent the skew of the surface-printed sheet 36 on the sheet receiver 45, and a part of the sheet re-feed unit 49 in FIG. The sheet receiving table 45 is moved to the drive shaft 155 so that the sheet re-feed sensor 52, the front conveyance roller 156, and the conveyance belt 158 wound around the re-feed sensor 52 are always positioned in the vicinity of the re-feed registration roller 51. 3, and a face plate (not shown) disposed inside the conveyor belt 158.

  The conveyance roller rear 154 and the conveyance roller front 156 are divided into skewers and formed of toothed rollers, and are formed of a high friction material having oil resistance (ink corrosion resistance) such as nitrile rubber (NBR). However, any material having such properties may be a resin or the like. The conveyance belt 158 is a toothed belt, and a plurality of belts are wound and stretched between a conveyance roller 154 and a conveyance roller front 156, which are divided into skewers. The conveyor belt 158 is formed of an elastic body having oil resistance, such as nitrile rubber (NBR) or silicone rubber (Q), and at least the outer peripheral surface of the rubber has fluorine rubber (FKM) or polytetrafluoroethylene. A film having ink repellency and oil resistance, such as resin, is smoothly coated. The suction fan 159 includes a fan drive motor as a fan drive means. Hereinafter, the “fan drive motor” is sometimes simply referred to as “suction fan 159” for the sake of simplicity.

The conveyor belt 158 is rotated in opposite directions by the belt drive motor 150 that is intermittently driven at a predetermined timing based on a command signal from the control device 100 when receiving the front surface printed paper 36 and when feeding it. It has become so.
The face plate has a shape that does not hinder the rotation of the conveyance roller rear 154 and the conveyance roller front 156 and the suction by the suction fan 159, and the width direction of the roller guides 59 a and 59 b and the movement plates 152 a and 152 b described later. A notch that allows displacement to Y is formed.

  The re-feed sensor 52 detects the front-side printed paper 36 when the front-side printed paper 36 is conveyed to the paper receiver 45 by the paper holding unit 60. The re-feed sensor 52 includes a reflective optical sensor and detects the front and rear edges of the front surface printed paper 36. The refeed sensor 52 is disposed in the vicinity of the refeed registration roller 51 on the sheet receiver 45.

  The displacing means 48 includes a rack (not shown) provided in the pair of housing side plates so as to form a fan shape centered on the drive shaft 155, a pinion (not shown) meshing with each of these racks, and connecting these pinions to the driven shaft. A shaft (not shown) fixed in parallel to the shaft 157, a worm wheel (not shown) fixed to the shaft, a worm (not shown) meshing with the worm wheel, and a swing shown in FIG. 3 as a displacement driving means for rotationally driving the worm. The motor 96 is mainly configured.

  The displacement means 48 is configured such that the pinion rotates when the peristaltic motor 96 is driven by the control device 100 in accordance with the vertical movement of the press roller 21, and the driven shaft 157 moves relative to the casing side plate pair. The stage 45 is swung around the drive shaft 155 so that the front of the transport roller 156 and the portion of the transport belt 158 wound around the transport roller 158 are always near the refeed resist roller 51 regardless of the vertical movement of the refeed resist roller 51. The paper tray 45 is driven so as to be positioned at the position.

  As shown in FIG. 8, the skew prevention means 151 is disposed on each side edge of the paper 36, and is used as a skew prevention member that engages and positions each side edge of the paper 36 to prevent skew. A pair of roller guides 59a and 59b in the paper width direction Y, movable plates 152a and 152b that are displaceable in the paper width direction Y according to the paper size and rotatably support the roller guides 59a and 59b, A rack portion 121 formed at the lower edge of the moving plate 152a and positioned below the face plate; a rack portion 122 formed at the lower edge of the moving plate 152b and facing the rack portion 121 and positioned below the face plate; A pinion 153 that is positioned below the face plate and meshes with the rack part 121 and the rack part 122, a stepping motor 123 as a driving means for driving the pinion 153 to rotate, and a moving plate 152a 152b and and a support means (not shown) and movably supported in the sheet width direction Y. Two roller guides 59a and 59b are provided in the sheet transport direction X, respectively.

  As shown in FIG. 9, the roller guides 59a and 59b are fixed to the movable plates 152a and 152b, and are rotatably fitted to and supported by the shaft portions 61a and 61b that are long in the substantially vertical direction, and the shaft portions 61a and 61b, respectively. It has roller parts 62a and 62b. Each of the roller portions 62a and 62b has a bell-shaped shape with a diameter decreasing upward, and has a circular cross section perpendicular to the longitudinal direction of the shaft portions 61a and 61b. The material of the rollers 62a and 62b is a lightweight plastic, and the side edges of the paper 36 are engaged so that the torque when rotating is reduced. Further, the outer surface is smooth, and the friction with the side edge of the paper 36 is reduced. The roller portions 62a and 62b are subjected to anti-friction processing in order to smooth the outer surface.

  As described above, each of the roller guides 59a and 59b is provided in two in the paper transport direction X. The number of roller guides 59a and 59b is equal to the skew of the front surface printed paper 36 and the front surface printed paper 36 as described later. As long as it can be reliably corrected without hindering the conveyance of the sheet, it may be one or three or more.

  The driving of the stepping motor 123 is controlled by the control device 100, and the interval between the maximum diameter portions of the roller portions 62 a and 62 b, that is, the portions closest to the moving plates 152 a and 152 b, in other words, the span is detected by the paper size detection sensor 117. The positions of the moving plates 152a and 152b are adjusted so as to coincide with the width of the paper 36 used for printing. In this embodiment, this adjustment is performed when the plate making start key 174 is pressed and the size of the paper 36 is detected by the paper size detection sensor 117 as will be described later. , 62b may be performed.

  Therefore, even if the front-side printed paper 36 is conveyed in a skewed state by the paper holding means 60, the roller guides 59a and 59b receive the front-side printed paper 36 with the roller portions 62a and 62b, and the front-side printed paper 36 Is controlled by the roller portions 62a and 62b whose diameter increases downward as it falls, and the rollers 62a and 62b are gradually corrected to a straight posture with respect to the traveling direction to eliminate skew. To do.

  At this time, since the outer surfaces of the roller portions 62a and 62b are smooth, the conveyance of the surface-printed paper 36 is prevented when the roller portions 62a and 62b abut on the surface-printed paper 36 and correct the posture. In addition, even if the surface-printed paper 36 comes into strong contact with the roller portions 62a and 62b and the friction with the roller portions 62a and 62b increases, the roller portions 62a and 62b rotate smoothly. The transport of the used paper 36 is not hindered.

  The sheet holding means 60 includes a sheet holding member 64 shown in FIG. 1 and a sheet holding position where the sheet holding member 64 is a first position shown in FIG. 1 and a standby position as a second position shown in FIG. And a support member (not shown) that is movably supported, and a drive means (not shown) that reciprocates the paper holding member 64 between the paper holding position and the standby position.

  The paper holding member 64 integrally has a paper front end holding member (not shown) that holds and holds the front end of the surface printed paper 36 at the paper holding position and opens the front end of the front surface printed paper 36 at the standby position. . The front-side-printed paper 36 is held and released by the paper front end holding member in a well-known configuration in conjunction with the paper holding member 64 being driven and displaced by the driving means. The home position of the sheet holding member 64 is a standby position, and normally occupies the standby position.

  The driving unit is controlled by the control device 100, and when the front surface printing is performed in the double-sided printing mode, when the press roller 21 occupies the printing position and the leading end of the peeling guide 46 rotates toward the plate cylinder 1 side, The holding member 64 is changed from the standby position to the sheet holding position, and then the surface-printed sheet 36 is moved from the standby position until the press roller 21 occupies the non-printing position and the leading end of the peeling guide 46 rotates toward the press roller 21 side. The sheet holding member 64 is displaced to the standby position at substantially the same speed as the speed fed from the nip portion between the cylinder 1 and the press roller 21.

  In order to eliminate the skew of the front surface printed paper 36 by the skew feeding prevention means 151, the paper front end clamping member opens the front end of the front surface printed paper 36, and the front surface printed paper 36 falls toward the paper receiver 45 and is conveyed. The sheet holding member 64 moves from the sheet holding position toward the standby position to transport the surface-printed sheet 36 depending on the strength of the holding force by the sheet leading end holding member. Done in the process of doing.

  In this embodiment, the skew of the front surface printed paper 36 is prevented in this way. However, as an operation for preventing the skew feeding, the front surface printed paper 36 is positioned between the roller portions 62a and 62b. The distance between the roller portions 62a and 62b is displaced between a first position that matches the width of the surface-printed paper 36 and a second position that is several millimeters larger than the width of the surface-printed paper 36, The skew cancellation operation may be performed by such displacement.

  Such a canceling operation may include at least one displacement from the second position to the first position. The timing of such displacement may be any time when at least a part of the surface-printed paper 36 is positioned between the roller portions 62a and 62b. However, the paper front end clamping member opens the front end of the surface printed paper 36 and It is preferable that the printed paper 36 falls toward the paper receiver 45 and is adsorbed by the conveyance belt 158. However, depending on the strength of the clamping force by the sheet leading edge clamping member, it may be until the sheet holding member 64 moves from the sheet holding position toward the standby position and transports the front surface printed sheet 36.

When such a canceling operation is performed, the roller portions 62a and 62b can be formed into a cylindrical shape by receiving the surface-printed paper 36 when the roller portions 62a and 62b occupy the second position.
These intervals when the roller portions 62a and 62b occupy the second position are about several millimeters larger than those when the roller portions 62a and 62b occupy the first position as described above. Assuming that the degree of skewing, i.e., the amount of rampage, is large, the difference in the size of the interval in the case of occupying the second position relative to the interval in the case of occupying the first position is It is preferable that the set value can be appropriately changed by inputting through the panel 173.

  As shown in FIG. 10, the positions of the roller portions 62 a and 62 b may be adjusted by detecting the positions of the roller portions 62 a and 62 b based on the phase of the pinion 116. In this case, the encoder 65 can be used as a detection means for detecting the phase of the pinion 116. The control device 100 receives a signal from the detection means such as the encoder, and the control device 100 adjusts the positions of the roller portions 62a and 62b according to the signal.

  According to such a configuration, the roller portions 62a and 62b are driven in conjunction with the side fences 110a and 110b so as to have the same interval as the interval between the side fences 110a and 110b. Therefore, the position of the rollers 62a and 62b can be adjusted accurately and easily in accordance with the width of the paper 36. Even if the paper 36 is a size other than the standard size, the positions of the roller portions 62a and 62b can be adjusted accurately and easily.

  Based on the above-described configuration, the operation including the operation procedure of the double-sided stencil printing apparatus 200 in this embodiment will be described. Since this operation is performed under the control of the control device 100, when describing detailed operations such as activation, operation, and stop of actuators (control target drive means) such as various motors and various solenoids, the control device 100 The expression based on the command or the command signal is omitted as much as possible.

  (Operation Example 1) First, an operation example 1 in which the single-sided printing mode is set and single-sided printing is performed will be described. The operation example 1 is substantially the same as the operation of performing single-sided printing with a conventional stencil printing apparatus, and the printing pressure range pattern III is used. In the first operation example, in order to facilitate understanding of each operation, the A3 size is used as the master size, and the A3 size is used as the document size and the paper size. Note that the continuous mode is not set and image position adjustment is not performed.

  The user loads A3 size paper 36 as a paper size used for printing on the paper feed tray 35, opens the pressure plate 142, and places an A3 size document to be printed on the contact glass 135, and then again. The pressure plate 142 is closed. Thereafter, after setting the plate making conditions using various keys on the operation panel 173, the single-sided printing key 188 is pressed to set the single-sided printing mode, and the plate-making start key 174 is pressed.

  The user confirms the single-sided printing mode by turning on the LED 188a, and then presses the plate making start key 174. When the plate making start key 174 is pressed, a paper size detection signal is sent from the paper size detection sensor 117 and a document size detection signal is sent from the document size detection sensor 149 to the control device 100. Compare each signal. At this time, if the paper size and the document size are the same, the image reading operation is immediately performed. If the paper size and the document size are different, the control device 100 displays the fact on the display device 190 and pays attention to the user. Prompt. When the paper size and the document size are different, enlargement / reduction scaling may be automatically performed in response to a command from the control device 100 to match the document size and the image size.

  When a plate making start key 174 is pressed to generate a start signal and is input to the control device 100, a series of operations from discharging to discharging are automatically performed. Prior to this, when the paper feed tray lifting / lowering motor is turned on, the paper feed tray 35 is raised, and the uppermost paper 36 comes into contact with the paper feed roller 33 to turn on a paper feed position detection sensor (not shown). When the control device 100 determines that the uppermost paper 36 is ready to be fed by detection, the paper feeding device 30 enters a paper feed standby state.

  First, in the plate removal unit 17, a plate removal operation for peeling the used master from the outer peripheral surface of the plate cylinder 1 is performed. When the plate making start key 174 is pressed, the plate cylinder 1 starts rotating. When the plate cylinder 1 reaches the home position at which the clamper 7 is substantially above, a home position signal is sent from the home position sensor to the control device 100. Sent. Receiving the home position signal, the control device 100 measures the number of pulses generated by the encoder (not shown) based on the home position, and the tip of the used master wound around the outer peripheral surface of the plate cylinder 1 is the driven roller 168. When it is determined that the predetermined plate discharging position corresponding to the endless belt 169 located on the outer peripheral surface of the main motor 20 has been reached, the operation of the main motor 20 is stopped.

  When the main motor 20 is stopped and the plate cylinder 1 is stopped at a predetermined plate discharging position, the main motor 20 and the plate discharging driving means 126 are operated to rotate the drive rollers 164 and 167 and the lower plate discharging member 161 is moved to the plate. The endless belt 169 that moves to the drum 1 side and is positioned on the outer peripheral surface of the driven roller 168 comes into contact with the used master. Then, the used master scooped up from the outer peripheral surface of the plate cylinder 1 by the rotation of the plate cylinder 1 and the movement of the endless belt 169 is nipped and conveyed by the lower plate discharging member 161 and the upper plate discharging member 160 to be outer periphery of the plate cylinder 1. It peels from the surface. The peeled used master is discarded in the discharge box 162 and then compressed by the compression plate 163. Even after all the used masters are peeled off from the outer peripheral surface, the plate cylinder 1 continues to rotate, and stops until the clamper 7 rotates to a predetermined plate feed standby position located substantially directly above. When the plate cylinder 1 stops at the plate feeding standby position, an opening / closing device (not shown) is operated to open the clamper 7, and the double-sided stencil printing apparatus 200 enters a plate feeding standby state.

  In parallel with the above plate removal operation, a document image reading operation is performed by the image reading unit 18. The original image is read by reflecting the reflected light illuminated by the fluorescent lamp 145 by the respective reflecting mirrors 143 and 144, and the reflected light related to the read original image is focused by the lens 146 and then image sensor 147. And is photoelectrically converted. The photoelectrically converted electrical signal is input to the A / D converter (not shown) in the main body frame 130, and then passes through a plate making control device (not shown) (which may be disposed in the control device 100). It is transmitted to a thermal head drive circuit (not shown).

  In parallel with the plate discharging operation and the image reading operation, the plate making unit 15 performs the plate making operation. That is, a digital image signal for controlling the heat generation of the heat generating elements of the thermal head 11 is transmitted to the thermal head 11 via a plate making control device and a thermal head driving circuit (not shown). As a result, the plurality of heating elements of the thermal head 11 are energized in a pulsed manner in the main scanning direction to selectively generate heat, and the master transport motor 10 is driven to rotate, whereby the platen roller 9 and the transport roller pair. 13 starts to rotate, and the thermoplastic resin film portion of the master 8 is selectively heated and punched according to image information while the master 8 is pulled out from the master roll 8a and is transported in the master transport direction X1.

  Then, the leading end of the master-made master 8Y is inserted between the clampers 7 that are guided by the master guide plate 14 and expanded with respect to the stage 6, and the number of steps of the master transport motor 10 reaches a certain set value, When it is determined that the front end of the master-making master 8Y has reached between the stage 6 and the clamper 7, the clamper 7 is closed by the opening / closing device, and the front-end of the master-making master 8Y is between the stage 6 and the clamper 7. Adsorbed and supported by

  After clamping the front end of the master 8Y, the plate cylinder 1 resumes rotating at a peripheral speed substantially the same as the master transport speed by the rotation of the main motor 20, and the master 8Y is subjected to the platen roller 9 and the transport roller pair 13. Is fed to be wound around the outer peripheral surface of the plate cylinder 1. When it is determined that the plate making to the master 8 and the carrying of the set amount of the plate-making master 8Y have been completed by the rotation driving of the master carrying motor 10 by a predetermined number of steps, the cutter 12 is operated to cut the plate-making master 8Y. At the same time, the rotation of the platen roller 9 and the conveyance roller pair 13 is stopped by stopping the rotation of the master conveyance motor 10.

  Then, when the rear end of the cut master 8Y is drawn out of the plate making section 15 by the rotation of the plate cylinder 1 and completely wound on the outer peripheral surface of the plate cylinder 1, the plate master 1 has been made. When the winding of the master 8Y is finished, the plate feeding operation is finished. When the winding of the plate-making master 8Y around the plate cylinder 1 is completed, the plate cylinder 1 starts to rotate at a predetermined peripheral speed in the direction of the arrow shown in FIG. Is done. Until the leading edge of the paper 36 crosses / passes the paper detection sensor 32, in other words, until the leading edge of the paper 36 is detected to be on by the paper detection sensor 32, the printing pressure range variable means 28 remains in an inoperative state. Thus, the press roller 21 is held at a non-printing position, that is, at an initial position separated from the outer peripheral surface of the plate cylinder 1.

  When the plate cylinder 1 rotates at a low speed in the direction of the arrow, first, the sheet feeding start shading plate is engaged with the sheet feeding registration sensor, so that the sheet feeding registration sensor is turned on to generate a sheet feeding start signal. The signal is a trigger to activate the paper feed motor 37 (start rotation driving). When the paper feed motor 37 is operated, the paper feed roller shaft 33a and the paper feed roller 33 rotate clockwise, so that the uppermost paper 36 on the paper feed tray 35 in contact with the paper feed roller 33 is While being conveyed, the sheet is separated into one sheet by the cooperative action with the separating member 34 and fed toward the nip portion of the registration roller pair 31 on the downstream side in the sheet conveying direction X.

  Next, the plate cylinder 1 further rotates in the direction of the arrow in FIG. 1 and the resist start light-shielding plate engages with the paper feed resist sensor, so that the paper feed resist sensor is turned on and a resist start signal is generated. The registration motor 41 is activated (starts rotational driving) with the signal as a trigger. The registration motor 41 is activated at a predetermined timing when the leading edge of the image area of the single-side plate-making image 8YA in the plate cylinder rotation direction of the plate-making master 8Y wound on the plate cylinder 1 reaches a position corresponding to the press roller 21. It is set to be the timing. When the registration motor 41 is operated, the shaft 31c rotates counterclockwise, so that the sheet 36 that is in contact with and waiting at the nip portion of the registration roller pair 31 is nipped between the plate cylinder 1 and the press roller 21. It is sent out to the department.

  Next, the leading edge of the paper 36 fed by the registration roller pair 31 is normally entered, that is, the leading edge of the paper 36 is within a predetermined time (or a predetermined power supplied to the registration motor 41) counted by the timer. This signal is input to the control device 100 when the paper detection sensor 32 detects the ON state within the number of pulses. Based on the detection signal of the leading edge of the sheet 36 from the sheet detection sensor 32 and the rotational position information of the plate cylinder 1 from the plate cylinder position detection sensor 29, the control device 100 operates the printing pressure range variable means 28.

  The press roller 21 has a sheet on the front end margin that is slightly to the left of the single-side plate-making image 8YA of the plate-making master 8Y whose outer peripheral surface is wound on the surface region 1A or the back surface region 1B of the plate cylinder 1 shown in FIG. 36 is pressed to be displaced to a printing position where printing pressure is applied. At the same time, the press roller drive motor 55 rotates the press roller 21 at a speed substantially equal to the peripheral speed of the plate cylinder 1, so that the press roller 21 rotates in the direction opposite to the rotation direction of the plate cylinder 1. By continuously pressing the sheet 36 against the plate-making master 8Y on the plate 1, the plate-making master 8Y is brought into close contact with the outer peripheral surface of the plate cylinder 1 and so-called printing is performed to fill the ink. In this printing, stencil printing is performed by the ink oozing from the opening portion of the opening 1a of the plate cylinder 1 to the punching portion of the master 8Y and transferred to the surface of the paper 36.

  At this time, the ink roller 2 also rotates in the same direction as the rotation direction of the plate cylinder 1. The ink in the ink reservoir 4 is attached to the surface of the ink roller 2 by the rotation of the ink roller 2, and the amount of the ink is regulated when passing through the gap between the ink roller 2 and the doctor roller 3. Supplied.

In this way, plate printing corresponding to the single-side plate-making image 8YA in the plate-making master 8Y on the plate cylinder 1 is performed, and the plate cylinder 1 is further rotated in the rear end margin portion slightly to the right of the rear end of the single-side plate-making image 8YA. The printing pressure application state by the press roller 21 is released.
When the plate cylinder 1 rotates in the direction of the arrow in FIG. 1 and the clamper 7 reaches the vicinity of the press roller 21 in pressure contact with the plate cylinder 1, the press roller 21 protrudes outward from the outer peripheral surface of the plate cylinder 1. It is separated from the clamper 7 and the interference between the press roller 21 and the clamper 7 is avoided.

  The single-sided printed paper 36 thus subjected to plate printing is further conveyed by the rotation of the plate cylinder 1 in the direction of the arrow in FIG. 1 while being pressed by the press roller 21, and the leading end of the single-sided printed paper 36 is the plate cylinder 1. The separation claw 170 and the separation fan 171 approaching the outer peripheral surface of the sheet are surely separated from the plate-making master 8Y on the plate cylinder 1 by the blowing air, and the separated single-side printed sheet 36 falls downward and is discharged and conveyed. The sheet 47 is conveyed to the downstream side in the sheet conveyance direction X while being attracted and held by the suction force of the suction fan 89 on the upper surface of the sheet discharge belt 88 rotated counterclockwise, and is transferred to the sheet discharge tray 172. Discharged.

  On the other hand, when the plate cylinder 1 makes approximately three quarters of a turn from the time when the press roller 21 contacts the outer peripheral surface of the plate cylinder 1, the press roller 21 returns to the non-printing position away from the outer peripheral surface of the plate cylinder 1. At the same time, the plate cylinder 1 is rotated to the home position again and stopped. After the plate-forming operation is finished, the double-sided stencil printing apparatus 200 enters a print standby state.

  Further, during paper feeding or plate-making, the platen roller 9 and the conveying roller pair 13 resume rotation, and the leading end of the cut master 8 is sent toward the nip portion of the conveying roller pair 13. If it is determined from the number of pulses of the master transport motor 10 that the tip of the cut master 8 has reached the nip portion of the transport roller pair 13 and has been sandwiched, the rotation of the platen roller 9 and the transport roller pair 13 stops, and the next It will be in the state of waiting for plate making in preparation for plate making.

  After the double-sided stencil printing apparatus 200 is in a print standby state, the test printing is performed when the test printing key 176 is pressed after inputting the printing conditions using the printing speed setting key 183 and various keys on the operation panel 173. When the trial printing key 176 is pressed, the plate cylinder 1 is driven to rotate at the set printing speed, and one sheet of paper 36 is fed from the paper feeding unit 30. The fed paper 36 is temporarily stopped by the registration roller pair 31 and then fed at the same timing as that at the time of printing. The press roller 21 is pressed against the plate-making master 8Y on the outer peripheral surface of the plate cylinder 1. The single-sided printed paper 36 on which the printed image is formed is reliably peeled off from the master-making master 8Y on the plate cylinder 1 by the peeling claw 170 and the peeling fan 171 as described above, and the peeled single-sided printed paper 36 is discharged. The paper is transported by the paper transport means 47 in the same manner as described above and discharged onto the paper discharge tray 172. It should be noted that according to the set printing speed, various motors such as the printing pressure range variable unit 28, the paper feeding unit 30, and the paper discharge conveying unit 47, and control target driving units such as various solenoids are at a speed and timing suitable for the printing speed. Each drive is controlled.

  When the position or density of the image is confirmed by trial printing, and the print start key 175 is pressed after the number of prints is input by the numeric keypad 179, the paper 36 is continuously fed from the paper supply unit 30, and the trial printing is performed. The printing operation is performed under the same conditions. When the set number of prints (predetermined number) has been consumed, the plate cylinder 1 stops at the home position, and the double-sided stencil printing apparatus 200 enters the print standby state again. Compared with the printing operation at the time of printing, the normal printing operation does not count the number of sheets 36 used for printing as described above as a normal normal printing number, and the setting desired by the user The main difference is that the operations of paper feeding, printing, and paper discharge at a speed corresponding to the printing speed are performed.

  When the leading edge of the paper 36 is not detected by the paper detection sensor 32 within a predetermined time counted by the timer of the control device 100, the control device 100 is located upstream of the registration roller pair 31 or the paper transport direction X. On the side, it is determined that the paper 36 is in a staying state due to a jam or the like, and the press roller 21 is held in the non-printing position. As a result, the press roller 21 occupies the printing position in spite of the absence of the paper 36, so that it comes into contact with the single-side plate-making image 8YA on the plate-making master 8Y on the plate cylinder 1 and the outer periphery of the press roller 21. The surface is prevented from being stained with ink. Such a control operation is the same in a continuous paper feeding operation in the double-sided printing mode, which will be described later, and will not be described below.

  Note that the reading operation in the image reading unit 18 may use an ADF 148 in addition to the above. The difference from the operation example 1 in this case is as follows. That is, when an A3-size document 133 is set on the document tray 134 of the ADF 148 by the user, the ADF 148 of the image reading unit 18 is operated in parallel with the plate discharging operation, so that one document 133 is read by the reading unit. The only difference is that it is delivered onto a certain contact glass 135. After that, as described above, the image of the original 133 is read as optical information by the operation of the scanner device 132.

  (Operation Example 2) Next, an operation example 2 in which the duplex printing mode is set and duplex printing is performed will be described. In this operation example 2, the printing pressure range pattern I and the printing pressure range pattern II are used. In operation example 2, in order to facilitate understanding of each operation, a master size of A3 is used, and a document size and a paper size of A4 are used. Hereinafter, the points different from the operation example 1 will be mainly described.

  The user stacks A4 size paper 36 as a paper size used for printing on the paper feed tray 35, opens the pressure plate 142, and places the first A4 size original for surface printing on the contact glass 135. After placing, the pressure plate 142 is closed again. Thereafter, after setting the platemaking conditions by using various keys on the operation panel 173, the duplex printing key 187 is pressed to set the duplex printing mode, and then the duplex printing mode is confirmed by turning on the LED 187a. Next, when the plate making start key 174 is pressed, a start signal is generated as in the single-sided printing mode, and this is input to the control device 100.

  Similarly to the first operation example, a paper size detection signal is sent from the paper size detection sensor 117 and a document size detection signal is sent from the document size detection sensor 149 to the control device 100. The control device 100 that receives these signals receives each signal. Compare signals. In this embodiment, since the maximum paper size that can be printed by the plate cylinder 1 during single-sided printing is A3 size, the paper size that can be used during double-sided printing is up to A4 landscape.

  As a result of comparing the document size and the paper size, if the two sizes are the same, the image reading operation is immediately performed. If the two sizes are different, the control device 100 displays a warning on the display device 190 as a warning. Call attention to the user. When the paper size and the document size are different from each other, an enlargement or reduction scaling is automatically performed by a command from the control device 100 to match the document size and the image size. It is good also as a structure which displays the procedure of rotation etc. and assists a user's operation. When the paper size exceeds A4 landscape orientation, the control device 100 causes the display device 190 to display a message to prohibit double-sided printing operation and prompt single-sided printing.

  When the plate making start key 174 is pressed, a series of operations from discharging to discharging are automatically performed as in the first operation example. Similarly to the first operation example, when the control device 100 determines that the uppermost sheet 36 in the sheet feeding tray 35 is ready to be fed, the sheet feeding unit 30 enters a sheet feeding standby state. After the plate removal operation similar to Operation Example 1 is performed, the plate cylinder 1 from which all used masters have been peeled off from the outer peripheral surface is stopped at the plate feed standby position as in Operation Example 1, and is opened and closed (not shown) The clamper 7 is opened by the device. In part in parallel with this plate discharging operation, the image reading unit 18 performs the reading operation of the first original image for front surface printing in the same manner as in Operation Example 1, and the image data signal passes through the plate making control device. It is transmitted to the thermal head drive circuit.

  In part in parallel with the plate discharging operation and the image reading operation, the plate making unit 15 performs plate making by the thermal head 11 as in the first operation example, and the master roll 8a to the master 8 are rotated by the rotation of the platen roller 9 and the conveying roller pair 13. The thermoplastic resin film portion of the master 8 is selectively heated and perforated according to image information while being transported in the master transport direction X1 while being pulled out, and a surface plate-making image 8A for surface printing is formed in the first half portion of the master 8. Is formed (see the divided master-making master 8X shown in FIG. 5).

  Then, the leading end of the divided prepress master 8X is inserted between the clampers 7 which are guided by the master guide plate 14 and expanded with respect to the stage 6, and the number of steps of the master transport motor 10 reaches a certain set value. When it is determined that the leading end of the divided plate-making master 8X has reached between the stage 6 and the clamper 7, the clamper 7 is closed by the opening / closing device, and the leading end of the divided plate-making master 8X is moved to the stage 6 and the clamper 7. Adsorbed and held between.

  After clamping the front end of the divided plate-making master 8X, the plate cylinder 1 resumes rotating at the same peripheral speed as the master conveyance speed by the rotation drive of the main motor 20, so that the divided plate-making master 8X becomes the platen roller 9 and the conveyance roller. The plate 13 is conveyed so as to be wound around the outer peripheral surface of the plate cylinder 1 and fed. If the controller 100 determines that the surface plate-making image 8A of the divided plate-making master 8X shown in FIG. 5 has been completed by the number of steps of the master conveyance motor 10, the platen roller 9, the conveyance roller pair 13, and the plate The rotation of the cylinder 1 is stopped, and the plate making standby state for making the back plate making image 8B for back printing in the next divided plate making master 8X is entered.

  Next, the user opens the pressure plate 142 again, places a second A4 size original for back side printing on the contact glass 135, and then closes the pressure plate 142 again. Thereafter, when the plate making start key 174 is pressed again, a start signal is generated and input to the control device 100. At this time, as in the case of the first document, the control device 100 compares the document size with the paper size and performs the same processing operation as described above. In the image reading unit 18, the reading operation of the second original image for back side printing is performed in the same manner as in the case of the first original, and the image data signal is driven by the thermal head via the plate making control device. Sent to the circuit. In the plate making unit 15, plate making is performed by the thermal head 11 as in the case of the first document, and the platen roller 9 and the carry roller pair 13 are rotated by the master carrying motor 10 being rotated again. While the master 8 is pulled out from the master roll 8a and transported in the master transport direction X1, the thermoplastic resin film portion of the master 8 is selectively heated and punched according to the image information, and the back surface of the master 8 is back. A reverse plate-making image 8B for printing is formed (see FIG. 5).

  At this time, the plate cylinder 1 resumes rotating at a circumferential speed substantially the same as the master conveyance speed, so that the latter half of the divided plate-making master 8X is wound around the outer circumferential surface of the plate cylinder 1 while being drawn out from the plate-making section 15. To go. Then, when the controller 100 determines that the last plate making image 8B of the divided plate making master 8X is completed by the number of steps of the master transport motor 10, the cutter 12 is operated and the divided plate making master is completed. The rear end portion of 8X is cut, the rotation of the platen roller 9 and the conveying roller pair 13 is stopped, and the rear end of the divided plate-making master 8X for one plate cut by the rotation of the plate cylinder 1 is the plate making section 15. The drawing and feeding operation of the divided plate-making master 8X to the plate cylinder 1 is completed.

  The document image reading operation and the image data input operation are not limited to the above-described example. For example, the document 133 is automatically transported onto the contact glass 135 using the ADF 148, or an image from an external device (not shown). It is good also as a structure which takes in data. Further, in the duplex printing mode, one original may be reversed and conveyed, and image data for two sheets may be acquired from the front and back surfaces. Further, in the duplex printing mode, one document for front and back printing may be reversed and conveyed, and image data for two sheets may be acquired from the front and back surfaces.

  In addition to the automatic conveyance operation of the original 133 by the ADF 148, or alone, an image memory (not shown) such as a bitmap memory for storing and storing image data related to the read original image is provided. The first and second image data may be stored and stored, and the plate making may be performed while sequentially calling the image data.

  On the other hand, when the winding of the divided plate-making master 8X to the plate cylinder 1 is completed, the plate cylinder 1 starts to rotate at a predetermined peripheral speed (usually, a low speed for printing) for printing. The paper feeding / printing process is started. Similar to the first operation example, the press roller 21 is held in the non-printing position until the leading edge of the paper 36 is detected to be on by the paper detection sensor 32.

  As the plate cylinder 1 rotates in the direction of the arrow, first, the paper feed motor 37 is activated in the same manner as in the operation example 1 by engaging the paper feed start shading plate with the paper feed registration sensor. When the paper feed motor 37 is operated, the uppermost first sheet 36 on the paper feed tray 35 in contact with the paper feed roller 33 is separated while being conveyed through the same operation as in the first operation example. The sheets are separated into a single sheet by the cooperative action with the member 34 and fed toward the nip portion of the registration roller pair 31. After the leading edge of the sheet 36 thus fed comes into contact with the nip portion of the registration roller pair 31, the sheet 36 is held in a state where a predetermined curved deflection is formed at the leading end portion of the sheet 36. Next, when the plate cylinder 1 further rotates in the direction of the arrow in FIG. 1 and the registration start light-shielding plate engages with the paper feeding registration sensor, the registration motor 41 is started in the same manner as in the first operation example. When the registration motor 41 is operated, the sheet 36 that has been waiting in contact with the nip portion of the registration roller pair 31 is directed between the plate cylinder 1 and the press roller 21 at a predetermined timing similar to that in the first operation example. Sent out. At this time, as in the operation example 1, the approach of the leading edge of the paper 36 fed by the registration roller pair 31 is normally detected by the paper detection sensor 32.

Next, based on the detection signal of the leading edge of the sheet 36 from the sheet detection sensor 32 and the rotational position information of the plate cylinder 1 from the plate cylinder position detection sensor 29, the control device 100 performs the printing pressure range variable means 28 as in the first operation example. Is activated.
As a result, as shown in FIG. 5, the press roller 21 has an outer peripheral surface slightly smaller than the surface plate-making image 8A of the divided plate-making master 8X wound on the surface region 1A of the plate cylinder 1 shown in FIG. The sheet 36 is pressed against the left end margin and displaced to a printing position where printing pressure is applied (see printing pressure ON timing by the press roller 21 in the printing pressure range pattern I shown in FIG. 5). At the same time, the press roller drive motor 55 rotates the press roller 21 at a speed substantially equal to the peripheral speed of the plate cylinder 1, so that the press roller 21 rotates in the direction opposite to the rotation direction of the plate cylinder 1. By continuously pressing the sheet 36 against the surface plate-making image 8A portion of the divided plate-making master 8X, the surface plate-making image 8A of the divided plate-making master 8X is brought into close contact with the outer peripheral surface of the plate cylinder 1 and filled with ink. So-called printing is performed. In this printing, ink oozes out from the opening portion of the opening 1a of the plate cylinder 1 to the perforated portion of the surface plate-making image 8A in the divided plate-making master 8X, and is transferred to the surface of the paper 36, thereby making stencil printing. Is done.

At this time, the ink roller 2 also rotates in the same direction as the rotation direction of the plate cylinder 1. The ink in the ink reservoir 4 is attached to the surface of the ink roller 2 by the rotation of the ink roller 2, and the amount of the ink is regulated when passing through the gap between the ink roller 2 and the doctor roller 3. Supplied.
Further, when the swing motor 96 of the displacement means 48 is driven, the sheet receiver 45 swings and displaces counterclockwise with the drive shaft 155 as a fulcrum, thereby occupying the position shown in FIG. At the same time, the paper holding member 64 is displaced to the paper holding position shown in FIG.

  Thus, plate printing corresponding to the surface plate-making image 8A in the divided plate-making master 8X on the plate cylinder 1 is performed, and in this process, the front end of the surface-printed paper 36 is held by the paper front end holding member, and in this state the paper The holding member 64 is displaced toward the standby position. When the paper holding member 64 occupies the standby position, the paper front end holding member opens the front end of the front surface paper 36, and the front surface printed paper 36 falls toward the conveyance belt 158 and is adsorbed. Is inclined to be substantially straight with respect to the traveling direction before being attracted to the conveyor belt 158, and the skew is corrected by the skew prevention means 151.

When the portion near the rear end of the surface plate-making image 8A reaches the rotation position corresponding to the printing nip portion 16a by the rotation of the plate cylinder 1, the control device 100 is based on the rotation position information of the plate cylinder 1 from the plate cylinder position detection sensor 29. Thus, the press roller 21 is held in a state where it is separated from the printing position and occupies a substantially non-printing position, and a paper feed standby state for the next paper feeding is entered.
At this time, when the swing motor 96 of the displacement means 48 is driven, the sheet receiver 45 swings and displaces clockwise with the drive shaft 155 as a fulcrum, thereby occupying the position shown in FIG.
The front end portion of the surface-printed paper 36 that has been subjected to plate printing corresponding to the surface plate-making image 8A in the divided plate-making master 8X on the plate cylinder 1 is blown by air from the peeling claw 170, the peeling guide 46, and the peeling fan 171. It is reliably peeled off from the divided plate-making master 8X on the plate cylinder 1.

  When the rear end of the front surface printed paper 36 passes the re-feed sensor 52, the rotational driving of the belt driving motor 150 is stopped once and then reversely driven for a predetermined time. As a result, the front end of the surface-printed paper 36 adsorbed and held on the conveyance belt 158 comes into contact with the nip portion between the press roller 21 and the re-feeding registration roller 51, and a predetermined curved deflection is printed on the surface. Formed at the leading end of the paper 36, the rotation of the conveyor belt 158 is temporarily stopped.

When it is determined that the plate cylinder 1 has reached the predetermined position, the belt drive motor 90 is driven again, and the conveyor belt 158 is rotated counterclockwise at a linear speed substantially the same as the peripheral speed of the plate cylinder 1.
At the same time, the press roller drive motor 55 is driven to rotate, so that the press roller 21 is rotated counterclockwise, so that the nip portion between the press roller 21 and the refeed resist roller 51 is placed. While the front end of the surface-printed paper 36 held in contact with the paper is sandwiched between the press roller 21 that rotates counterclockwise and the re-feeding registration roller 51 that rotates clockwise in accordance with this, The plate cylinder 1 and the press roller 21 are pressed against each other by being guided by the roller guide plate 50 so as to be conveyed along the outer peripheral surface of the press roller 21 at a substantially same peripheral speed as the plate cylinder 1. Then, the sheet is conveyed while being turned upside down toward the nip portion formed.

  In parallel with this conveyance, when the predetermined rotation position of the plate cylinder 1, that is, the vicinity of the front end of the back plate-making image 8B on the divided plate-making master 8X on the plate cylinder 1 reaches the rotation position corresponding to the nip portion, the press roller 21 Has a printing pressure by pressing the back surface of the surface-printed paper 36 against the leading edge portion slightly left of the back plate-making image 8B of the divided plate-making master 8X wound on the back surface region 1B of the plate cylinder 1. By shifting to the printing position to be applied, double-sided printing for printing is performed (see printing pressure ON timing by the press roller 21 in the printing pressure range pattern II shown in FIG. 5).

  In this way, the double-sided printed paper 36 for printing on which double-sided printing has been performed corresponding to the backside plate-making image 8B in the divided pre-made master 8X on the plate cylinder 1 is the same as the discharge operation of the single-sided printed paper 36. The double-sided printed paper 36 that has been peeled off from the divided master-making master 8X on the plate cylinder 1 by the air from the peeling claw 170 and the peeling fan 171 whose front end approaches the outer peripheral surface of the plate cylinder 1 is peeled off. The paper falls to the lower side and is sent to the paper discharge conveyance unit 47, and is conveyed to the downstream side in the paper conveyance direction X while being attracted and held by the suction force of the suction fan 89 on the upper surface of the paper discharge belt 88. To be discharged. Since the double-sided printed paper 36 printed by printing is always in a substantially straight posture on the paper receiver 45 with respect to the traveling direction, the position where the printing is performed by the front plate making image 8A and the back plate making. The position where printing is performed by the image 8B is exactly the same, and there is no image position shift.

  On the other hand, when the plate cylinder 1 makes approximately three quarters of a turn from when the press roller 21 contacts the outer peripheral surface of the plate cylinder 1, the press roller 21 returns to a non-printing position away from the outer peripheral surface of the plate cylinder 1. The plate cylinder 1 is again rotated to the home position and stopped. After the plate setting operation is completed, the duplex stencil printing apparatus 200 enters a printing standby state for the next regular duplex printing.

  After the double-sided stencil printing apparatus 200 is in a print standby state, the test printing is performed when the test printing key 176 is pressed after inputting the printing conditions using the printing speed setting key 183 and various keys on the operation panel 173. When the trial printing key 176 is pressed, the plate cylinder 1 is driven to rotate at the set printing speed, and one sheet 36 is fed from the paper supply unit 30 during the first rotation of the plate cylinder 1 during duplex printing. After feeding, printing corresponding to the surface plate-making image 8A in the divided plate-making master 8X on the plate cylinder 1 is performed, and after being guided and conveyed to the paper receiver 45 by the peeling guide 46, the double-side printing is performed. At the second rotation of the plate cylinder 1 at that time, the front-side printed paper 36 is re-fed by the re-feeding means 49 and printing corresponding to the back-side plate-making image 8B is performed on the back side, and the double-side printed paper 36 is discharged Guided and conveyed to the paper unit 19.

The double-sided printed paper 36 printed by the trial printing is always substantially straight with respect to the traveling direction on the paper receiver 45, similarly to the double-sided printed paper 36 printed by printing. The position where printing is performed with the front plate-making image 8A and the position where printing is performed with the back-side plate-making image 8B are exactly the same, and no image position deviation occurs.
In accordance with the set printing speed, the control target drive means such as various motors such as printing pressure range variable means 28, paper feed section 30, paper discharge conveying means 47, displacement means 48, refeed means 49, and various solenoids. Are driven and controlled at a speed and timing suitable for the printing speed.

  When the position or density of the image is confirmed by trial printing, and the print start key 175 is pressed after the number of prints is input by the numeric keypad 179, the paper 36 is continuously fed from the paper supply unit 30, and the trial printing is performed. The printing operation is performed under the same conditions. When the set number of prints (predetermined number) has been consumed, the plate cylinder 1 stops at the home position, and the double-sided stencil printing apparatus 200 enters the print standby state again. Compared with the double-sided printing operation at the time of printing, the normal regular double-sided printing operation does not count the number of sheets 36 used for printing as described above as the normal normal printing number, and the user However, the only difference is that operations such as paper feeding, refeeding, front surface printing, back surface printing, and paper discharge are performed at a speed corresponding to a desired set printing speed.

  As described above, in the normal regular double-sided printing operation, the set number of double-sided printings is performed every two rotations of the plate cylinder 1, and the surface plate-making image 8A of the divided plate-making master 8X in the odd-numbered rotations of the plate cylinder 1. The front side printing corresponding to the back side printing corresponding to the back side plate making image 8B of the divided plate making master 8X is performed in this order in the even rotation of the plate cylinder 1.

  The double-sided printed paper 36 printed by normal regular printing is always substantially straight with respect to the traveling direction on the paper receiver 45, similarly to the double-sided printed paper 36 printed by printing and trial printing. Since it is in the posture, the position printed by the front plate making image 8A and the position printed by the back plate making image 8B are exactly the same, and no image displacement occurs. Therefore, a high quality printed matter can be obtained.

  As described above, the stencil printing apparatus 200 as the image forming apparatus has been described as an embodiment for carrying out the present invention. However, the image forming apparatus to which the present invention is applied is not limited to the stencil printing apparatus but other types such as an offset printing apparatus. Any type of image forming apparatus such as a copying machine, a printer, or a facsimile machine may be used.

  The skew prevention member can be applied to only one side edge of the paper so long as it can eliminate the skew of the paper, such as an image forming apparatus in which the paper size is fixed or an image forming apparatus that forms an image on one side. It may be arranged. In addition, the skew prevention member may be fixed and not movable in the width direction of the paper as long as it can eliminate the skew of the paper, such as an image forming apparatus in which the paper size is fixed. As long as it does not hinder the conveyance of the sheet, it may be fixed and not rotatable.

The skew prevention member can be configured to be gripped and moved directly by hand, or can be configured to be moved by a user's instruction using an input unit such as an operation panel. In this case, the detection unit and the control unit are appropriately omitted. be able to.
The application of the present invention is not limited to the above-described embodiment unless particularly limited in the above description.

It is a partial cross section front view of the principal part of the double-sided stencil printing apparatus to which this invention is applied. It is a front view of the principal part of the image reading part of the double-sided stencil printing apparatus shown in FIG. It is a block diagram which shows the control structure of the principal part of the double-sided stencil printing apparatus shown in FIG. It is a top view of the principal part of the operation panel of the double-sided stencil printing apparatus shown in FIG. FIG. 2 is a diagram for developing and explaining three printing pressure range patterns applied corresponding to a divided master-making master on a plate cylinder used in the double-sided stencil printing apparatus shown in FIG. 1. It is a front view of another state of the double-sided stencil printing apparatus shown in FIG. FIG. 2 is a perspective view showing a tray of a paper feeding unit of the double-sided stencil printing apparatus shown in FIG. 1, a guide member for tray-shaped paper, and detection means for detecting the position of the guide member. FIG. 2 is a plan view showing a part of skew feeding preventing means of the double-sided stencil printing apparatus shown in FIG. 1. It is a front view of the skew prevention member with which the skew prevention means shown in FIG. 8 was equipped. It is the conceptual diagram which showed the skew prevention means of a different structure from the skew prevention means shown in FIG.

Explanation of symbols

35 tray 36 sheet 45 refeed tray 59a skew prevention member 59b skew prevention member 59a, 59b pair of skew prevention member 100 control means 110a, 110b guide member 117, 118a, 118b detection means 123 of skew prevention member Driving means 151 Skew prevention means 200 Double-sided image forming apparatus, stencil printing apparatus

Claims (9)

A paper re-feed tray on which an image is formed on one side and on which the paper on which the image is formed is placed on the other side;
A skew prevention means for engaging the paper and preventing the skew of the paper on the refeed tray;
A double-sided image forming apparatus comprising a skew prevention member that is rotatable when the skew prevention means is engaged with a side edge of the sheet and prevents the skew of the sheet.   2. The double-sided image forming apparatus according to claim 1, wherein the skew feeding preventing member is disposed and paired with each side edge of the paper.   3. The double-sided image forming apparatus according to claim 1, wherein the skew feeding preventing member is movable in the width direction of the paper.   4. The double-sided image forming apparatus according to claim 3, wherein the double-sided image forming apparatus is dependent on the double-sided image forming apparatus according to claim 2, and at least when the sheet is positioned between the pair of skew feeding preventing members. The double-sided image forming apparatus, wherein the pair of skew prevention members occupy a position where the interval is substantially the same as the width of the sheet.   5. The double-sided image forming apparatus according to claim 3, further comprising: a driving unit that drives the skew feeding preventing member in the width direction; and a control unit that controls the driving unit to displace the skew feeding preventing member. A double-sided image forming apparatus.   6. The double-sided image forming apparatus according to claim 5, wherein the control unit engages the pair of skew prevention members with the sheet when the sheet is positioned between the pair of skew prevention members. The double-sided image forming apparatus is characterized in that the double-sided image forming apparatus is displaced between a first position for preventing the skew of the sheet and a second position separated from the sheet.   7. The double-sided image forming apparatus according to claim 5, wherein a tray on which sheets on which image formation is performed is stacked, and is displaceable in a width direction of the sheets stacked on the tray and engages with a side edge of the sheets. A guide member for positioning the paper on the tray and a detecting means for detecting the position of the guide member in the width direction of the paper, and the control means detects the detection by the detecting means. A double-sided image forming apparatus, wherein the skew prevention member is displaced based on a position of a guide member.   8. The double-sided image forming apparatus according to claim 1, wherein the skew prevention member has a shape whose diameter decreases upward. 9. The double-sided image forming apparatus according to claim 1, wherein the double-sided image forming apparatus is a stencil printing apparatus.

Images