JP2014177001A - Stencil printer and stencil printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stencil printer which prevents a printing form from curling up when discharged and is also adaptive to high-speed printing.SOLUTION: A stencil printer includes first and second piston pumps 27, 36, and air discharge/feed systems AS1, AS2 which supply compressed air generated by the piston pumps 27, 36 together to a paper discharge claw member 19 by merging, and sets a normal printing mode in which one printing form 4 is fed for one rotation of a cylindrical printing cylinder to be printed, and a printing controlled mode including a double-speed printing mode in which two printing forms 4a, 4b are fed successively for one rotation of the cylindrical printing cylinder. In the normal printing mode, the first piston pump 27 is driven in timing corresponding to the position of a front end 4af of a first printing form 4a and in the double-speed printing mode, the second piston pump 36 is driven in timing corresponding to the position of a front end 4bf of a second printing form 4b in addition to an operation on the first printing form 4a, so that the printing forms are supplied from the air discharge/feed systems AS1, AS2 to the paper discharge claw member 19.

Description

  The present invention relates to a stencil printing apparatus and a stencil printing method, and more particularly to a stencil printing apparatus and a stencil printing method capable of double speed printing.

  Digital stencil printing apparatuses are used in multi-copy printing applications in educational markets and government offices. In the stencil printing apparatus, since one stencil stencil sheet (usually master stencil master) is wound around a cylindrical plate cylinder, printing is always performed once on one sheet by one rotation of the plate cylinder. Done. Since the size of the stencil sheet corresponds to A3 paper, A3 size printing is possible. If two A4 size images are arranged side by side on a stencil sheet (two side master making) and two A4 size sheets are fed continuously, one rotation of the plate cylinder makes two rotations for two sheets. Printing is possible. In this way, printing can be performed at a speed of 240 sheets / minute when the rotational speed of the plate cylinder is 120 rpm. This is double speed printing. Such a double-speed printing configuration is disclosed in, for example, JP-A-2002-29133 (Patent Document 1).

  Such a conventional stencil printing apparatus uses an air compression pump in which a piston reciprocates using a crank mechanism that rotates in synchronization with the rotation of a cylindrical plate cylinder, and compressed air generated by the air compression pump. The pipe is guided by a pipe and discharged from the tip of the paper discharge peeling claw, and the tip of the printed paper is peeled off from the outer peripheral surface of the cylindrical plate cylinder in a non-contact manner.

  In normal printing in which printing is performed once on one sheet of paper with one rotation of the plate cylinder, there has been no problem with the paper leading edge peeling method in which compressed air is discharged from such a paper discharge peeling claw. However, in the case of double speed printing, there is no problem in peeling the first sheet of paper with one rotation of the plate cylinder, but the printing paper cannot be peeled because the second sheet does not discharge compressed air. In addition, there is a case where a phenomenon referred to as paper discharge roll-up in which the paper is wound around the conveyance and is not peeled off may occur.

  On the other hand, for example, a technique described in JP-A-2006-212982 (Patent Document 2) is also known. The technique described in Patent Document 2 is to change the number of times of air ejection from the tip of the paper discharge claw for one rotation of the printing drum according to the image information on the paper and the paper thickness information. That is, with this technique, air can be discharged twice for one rotation of the printing drum.

  Further, in Japanese Patent Application Laid-Open No. 2005-212210 (Patent Document 3), a sheet peeling member has a first position corresponding to the leading edge of the sheet, and a second position located downstream of the first position in the sheet conveying direction. Discloses that air can be ejected from the ejection port of the peeling member. Also, having an air compression piston pump having a first cylinder and a piston, and a second cylinder and a piston, and operating only the first piston and operating the first and second pistons at different timings. It is described that there is. Furthermore, it has a 1st peeling member and a 2nd peeling member by double-sided printing, a 1st peeling member discharges air in the drum rotation direction 1st position, and a 2nd peeling member is a drum rotation direction 2nd position. It also describes discharging air.

  In response to the phenomenon of paper discharge roll-up, for example, the technique disclosed in Patent Document 2 can be used to change the number of times of air discharge from the front end of the paper discharge peeling claw for one rotation of the printing drum to correspond to double speed printing. it can. That is, when the number of times of air discharge is set to 2 per rotation of the plate cylinder, when the rotation speed of the plate cylinder is 120 rpm, it is necessary to rotate the crank mechanism at a high speed of 240 rpm and drive the air compression piston pump. Therefore, the required torque of the pump drive motor becomes abnormally large, and the time during which the compressed air is discharged from the discharge pawl tip is shortened. Also, there is no problem with the first compressed air discharge timing, but the second compressed air discharge timing does not exactly coincide with the leading edge of the second sheet, and the discharge of the second sheet is rolled up (with respect to the plate cylinder). The function of preventing wrapping at the time of paper discharge will be significantly reduced.

  Patent Document 3 discloses that the air compression piston pump has a first cylinder and a piston, and a second cylinder and a piston, and the first and second pistons are different from the case where only the first piston is operated. It is disclosed to operate at timing.

  Further, in the normal printing mode, when each of the two piston pumps for driving the piston pump has a dedicated motor, it is necessary to drive in synchronization with the rotation of the cylindrical plate cylinder. If the printing speed is up to about 120 sheets / min, the rotational drive of the motor can follow the synchronization, but if it becomes faster than that, a motor with a particularly large power will be required, and it will be a big problem when installing Space is required and, of course, costs increase.

  In recent years, since the printing speed has been accelerated from 150 sheets / minute to 180 sheets / minute and further 200 sheets / minute, the piston pump described in the cited document 3 cannot cope with such high speed.

  Therefore, the problem to be solved by the present invention is to make it possible to cope with the increase in speed of stencil printing while preventing the printing paper from being rolled up.

  In order to solve the above-mentioned problems, the present invention feeds one sheet of printing paper for one rotation of a cylindrical plate cylinder in which a normal stencil master in which one image is made on one stencil sheet is mounted. The normal printing mode for printing and the two printing papers continuously for one rotation of the cylindrical plate cylinder on which the two-side plate making master on which two images are made on one stencil sheet is mounted In the stencil printing apparatus in which the double-speed printing mode for feeding and printing on the two sheets is set as the printing control mode, in the normal printing mode, the printing paper and the printing paper are printed at a timing corresponding to the leading edge position of the first printing paper. Compressed air is supplied from the first compressed air supply means between the outer peripheral surface of the cylindrical plate cylinder and the printing paper is peeled off from the outer peripheral surface. In the double speed printing mode, compressed air in the normal printing mode is released. Like supply A second print sheet is peeled off from the outer peripheral surface, and a second sheet is formed between the second print sheet and the outer peripheral surface of the cylindrical plate cylinder at a timing corresponding to the tip position of the second print sheet. The apparatus includes a peeling unit that supplies compressed air from the compressed air generating unit and separates the second print sheet from the outer peripheral surface. Note that problems, configurations, and effects other than those described above will be clarified in the following description of embodiments.

  According to the present invention, it is possible to cope with an increase in the speed of stencil printing while preventing the printing paper from being rolled up.

It is a figure which shows schematic structure of the printing part of the stencil printing apparatus of Example 1 which concerns on embodiment of this invention. FIG. 3 is a diagram illustrating a schematic configuration of a printing unit of the stencil printing apparatus showing a state of completion of printing on the first sheet in the double speed mode according to the first exemplary embodiment. It is a figure which shows schematic structure of the compressed air discharge mechanism which discharges the peeling compressed air from the nozzle in Example 1. FIG. It is explanatory drawing which shows the relationship between the printing pressure and discharge pressure corresponding to the state which expand | deployed the cylindrical plate_cylinder | printing_drum in Example 1, and the preprinted base paper with which it is mounted | worn. FIG. 3 is an explanatory diagram illustrating a relationship between a printing pressure and a discharge pressure corresponding to a state in which a cylindrical plate cylinder and a pre-made base paper mounted thereon are developed in the double speed printing mode according to the first exemplary embodiment. 1 is a block diagram illustrating a control configuration of a stencil printing apparatus according to Embodiment 1. FIG. FIG. 6 is an explanatory diagram illustrating a relationship between a printing pressure and a discharge pressure corresponding to a state in which a cylindrical plate cylinder in a digital stencil printing apparatus according to a second embodiment and a stencil sheet that is mounted on the cylindrical plate cylinder are developed. FIG. 10 is an explanatory diagram illustrating a relationship between a printing pressure and a discharge pressure corresponding to a state in which a cylindrical plate cylinder in a digital stencil printing apparatus according to a third embodiment and a stencil sheet that is mounted on the cylindrical plate cylinder are developed. FIG. 10 is a diagram illustrating a schematic configuration of a printing unit of a digital stencil printing apparatus according to a fourth embodiment. FIG. 10 is a diagram illustrating a schematic configuration of a printing unit of a digital stencil printing apparatus showing a printing end state on the first printing paper 4a in the double speed mode in the fourth embodiment. FIG. 10 is an operation explanatory diagram illustrating an operation of a registration roller unit in the fourth embodiment. FIG. 10 is an explanatory diagram showing a relationship between a stencil sheet and an image when making an image on the stencil sheet in Example 4. FIG. 10 is an explanatory diagram showing a relationship between a stencil sheet and an image when making an image on the stencil sheet in Example 5. FIG. 10 is a diagram illustrating an effective image area for an A4 paper size according to Embodiment 6. FIG. 10 is a diagram showing a plate making state when there is a margin of A4 paper in Example 6. FIG. 10 is a block diagram illustrating a control configuration of a stencil printing apparatus according to a sixth embodiment. 10 is a timing chart illustrating sheet conveyance drive control timing of a sheet feeding and conveying apparatus according to a sixth embodiment.

  In the double-speed printing mode capable of high-speed printing, the present invention performs necessary and appropriate compressed air ejection not only when the first sheet of paper is rotated once but also when the second sheet is peeled. By this, the printing paper is surely peeled off.

  Embodiments of the present invention will be described below with reference to the drawings. In the description of each embodiment, the same reference numerals are given to the same or the same components, and duplicate descriptions are omitted as appropriate.

  FIG. 1 is a diagram illustrating a schematic configuration of a printing unit of the digital stencil printing apparatus according to the first embodiment.

  The digital stencil printing apparatus SPR includes a printing unit PRP including an ink supply device 2, a cylindrical plate cylinder 3, a press roller 5, a press roller support arm 12, and a fulcrum shaft 13. The digital stencil printing apparatus SPR is hereinafter simply referred to as a stencil printing apparatus SPR.

  When the stencil printing apparatus SPR performs printing with the printing unit PRP, first, the stencil sheet 1 punched and stenciled by a plate making apparatus (not shown) is fed and wound around the outer peripheral surface of the cylindrical plate cylinder 3. Next, the printing paper 4 is separated and fed one by one by a paper feeding device (not shown), and pressed against the stencil paper 1 on the outer periphery of the cylindrical plate cylinder 3 by pressing of the press roller 5. By this close contact operation, the ink is passed through the perforated portion of the stencil sheet 1, and the passed ink is transferred to the printing paper 4 to form a printed image. An ink supply device 2 is provided inside the cylindrical plate cylinder 3.

  In the plate making operation, a document image read by a scanner is stored in a memory, and punching and plate making is performed at a predetermined position of the stencil sheet 1 according to image information stored in the memory by a thermal head of a plate making apparatus 55 (see FIG. 6). Is done. In the case of the “normal printing mode”, in this embodiment, it is possible to print a maximum A3 size image. In this case, the maximum printing speed is, for example, 120 sheets / minute (the rotational speed of the cylindrical plate cylinder is 120 rpm). .

  When the “double speed printing mode” is selected by the operation unit, two sheets of images having a maximum A4 size are arranged side by side on a single stencil sheet 1. Thereby, it is possible to print an image having a maximum size of A4. In this case, the maximum printing speed is, for example, 240 sheets / minute (the rotational speed of the cylindrical plate cylinder 3 is 120 rpm). Note that both the normal printing mode and the double speed printing mode are printing control modes set by the main body central control device 52 described later.

  In the plate-making operation in the “double speed printing mode”, it is standard to take out one A4 image from the memory and make the two side-by-side plate making, but the two A4 images on the first and second pages are made side-by-side. It is also possible. In that case, if there are two pages, the printed matter is stacked on a paper discharge tray (not shown) in a form collated in page order.

  A registration roller unit 9 including a lower registration roller 6 and an upper registration roller 7 is provided on the upstream side of the printing unit PRP in the conveyance direction. In the registration roller unit 9, the lower registration roller 6 is a driving roller, and the upper registration roller 7 is a driven roller that rotates while being pressed against the lower registration roller 6. The lower registration roller 6 is driven by a dedicated stepping motor 25 via a timing belt 24.

  In the case of printing, the printing paper 4 is fed toward the printing unit PRP by controlling the driving timing of the lower registration roller 6 in synchronization with the rotation of the cylindrical plate cylinder 3, and the print image on the printing paper 4 is printed. Adjust the position. In addition, a fixed upper guide plate 10 and a fixed lower guide plate 11 are fixed to the registration roller unit 9 at a predetermined interval to guide the printing paper 4, and the printing paper 4 is fixed to the upper and lower registration rollers 6, 7. Is guided to the nip 6a and further guided to the printing unit PRP.

  Since the stencil sheet 1 made from the plate is clamped at its tip by a base paper clamper 8 provided at a part of the outer periphery of the cylindrical plate cylinder 3, the clamper portion protrudes outward from the cylindrical plate cylinder 3. ing. In order to avoid the collision with the convex portion, the press roller 5 swings in the vertical direction in the figure and reciprocates with the printing pressure ON and OFF. The printing pressure is turned ON / OFF by a cam mechanism (not shown). The press roller 5 is supported on the swing end side of the press roller support arm 12 that swings around the fulcrum shaft 13 and swings around the fulcrum shaft 13.

  The printing paper 4 on which an image is formed at the printing nip 5a formed between the cylindrical plate cylinder 3 and the press roller 5 of the printing unit PRP is peeled off from the cylindrical plate cylinder 3 and discharged by an air suction belt type. The paper is transported by a transport device 14 toward a paper discharge tray (not shown). The air suction belt type paper discharge conveyance device 14 includes two rollers 15, 16, a plurality of endless perforated belts 17 spanned between the rollers 15, 16, and the printing paper 4 through the holes of the belt 17. It comprises an air suction device 18 for sucking the back surface.

  FIG. 1 shows a state immediately after the front end of the printing paper 4 is pressed against the cylindrical plate cylinder 3 by the press roller 5 and printing is started. In this state, in order to peel the printing paper 4 that has passed through the printing pressure nip 5a from the cylindrical plate cylinder 3, the leading end of the paper discharge claw member 19 approaches the cylindrical plate cylinder 3, and the paper discharge claw member is further removed. The compressed air that has passed through the pipe 21 is discharged from the nozzle 20 in the vicinity of the tip 19. An air knife 22 is provided on the downstream side of the printing nip 5a in the transport direction in order to peel the printed printing paper 4 from the stencil sheet 1 and transport it. The air knife 22 generates a strong air pressure by the blower fan 23 and blows air toward the printing pressure nip portion 5a. The blowing air acts so as to peel the printing paper 4 from the stencil sheet 1, but the air knife 22 blows continuously during printing.

  FIG. 2 is a diagram showing a schematic configuration of a printing unit of the digital stencil printing apparatus showing a state where printing on the first sheet is completed (immediately before starting printing on the second sheet) in the double speed mode.

  In the figure, the second printing paper 4b is conveyed after the first printing paper 4a in the double speed mode printing. In this embodiment, the distance H between the rear end 4ae of the first printing paper 4a and the leading edge 4bf of the second printing paper 4b is about 20 to 30 mm. The first side plate-making image perforated on the stencil sheet 1 is printed on the first printing paper 4a, and the second side plate-making image is printed on the second printing paper 4b. The first side plate-making image and the second side plate-making image are made on one stencil sheet with the same interval of 20 to 30 mm corresponding to the interval of 20 to 30 mm of the printing paper 4a and 4b.

  2 shows that the discharge of compressed air for peeling onto the first printing paper 4a from the nozzle 20 of the paper discharge claw member 19 is completed, and the tip 4bf of the second printing paper 4b is connected to the cylindrical plate cylinder. 3 shows a state in which the discharge of compressed air for peeling from 3 has started. The press roller 5 continuously maintains the printing pressure ON state from the first printing paper 4a to the second printing paper 4b.

  Immediately downstream of the nip 6a between the lower registration roller 6 and the upper registration roller 7 on the downstream side in the paper conveyance direction, a print paper trailing edge detection sensor 26 is provided. The print paper trailing edge detection sensor 26 may be provided immediately upstream of the nip 6a in the paper conveyance direction. The motor 25 that drives the lower registration roller 6 continues to feed the first printing paper 4a, but when the sensor 26 detects the trailing edge 4ae of the first printing paper 4a, the rotation is stopped immediately and the second printing is performed. The front end 4bf of the paper 4b is received by the nip 6a. Then, when the second printing paper 4b forms a slight deflection, the second printing paper 4b is rotated again to start feeding the second printing paper 4b. At this time, the drive timing is controlled so that the distance H between the trailing edge 4ae of the first printing paper 4a and the leading edge 4bf of the second printing paper 4b becomes a predetermined value as described above.

  FIG. 3 is a diagram showing a schematic configuration of a compressed air discharge mechanism for discharging compressed air for peeling from the nozzle 20.

  The compressed air discharge mechanism basically includes a first air exhaust system AS1, a second air exhaust system AS2, and a common air exhaust pipe 47.

  The first air exhaust system AS1 includes a first piston pump 27, a first drive connecting link 32, a first crank large gear 33, a first small gear 34 that meshes with the first crank large gear 33, and a first crank large gear 33. Includes a first pump motor 35 and a first compressed air exhaust pipe 30. The first piston pump 27 further includes a first cylinder body 28, a first piston 29 that reciprocates therein, a first compressed air exhaust pipe 30, and a first one-way valve 31. The first compressed air exhaust pipe A first check valve 30 is provided at 30.

  The second air exhaust system AS2 includes a second piston pump 36, a second drive connecting link 41, a second crank large gear 42, a second small gear 43 that meshes with the second crank large gear 42, and a second crank large gear 42. Includes a second pump motor 44 and a second compressed air discharge pipe 39. The second piston pump 36 further includes a second cylinder body 37, a second piston 38 that reciprocates therein, a second compressed air exhaust pipe 39, and a second one-way valve 40, and the second compressed air exhaust pipe. A second check valve 46 is provided at 39.

  The common air exhaust pipe 47 is connected to first and second compressed air exhaust pipes 30 and 39 provided with first and second check valves 45 and 46, respectively.

  The state shown in FIG. 3 is a state in which the first crank large gear 33 and the second crank large gear 42 are rotationally driven in the direction of the arrow R1 in the figure. In this state, the first piston pump 27 moves the first piston 29 forward, and sends out compressed air from the first compressed air discharge pipe 30. On the other hand, the second piston pump 36 causes the second piston 38 to return and sucks air from the outside through the second one-way valve 40. As described above, a part of the first compressed air exhaust pipe 30 is provided with the first check valve 45, and a part of the second compressed air exhaust pipe 39 is provided with the second check valve 46. Is provided. The two check valves 45 and 46 prevent the compressed air from the first piston pump 27 from flowing to the second piston pump 36 as it is. The same applies to the reverse case.

  The compressed air sent from the first compressed air discharge pipe 30 and the compressed air sent from the second compressed air discharge pipe 39 are combined on the downstream side of the first and second check valves 45 and 46 to form common air. It is sent to the discharge pipe 47. Then, the ink is ejected from here through the nozzle 20 on the front end side of the paper discharge claw member 19 toward the printing nip portion 5a. The first and second one-way valves 31 and 40 can also be provided on the first and second pistons 29 and 38, respectively.

  The first and second crank large gears 33 and 42 are controlled to rotate in synchronization with the rotation of the cylindrical plate cylinder 3. For this purpose, the rotational speed is calculated and controlled in accordance with the rotational speed of the cylindrical plate cylinder 3. At that time, it is necessary to perform correction control for matching the rotation reference position every time. Therefore, in the present embodiment, the first sensor 49 detects the first protrusion 48 provided on the first crank large gear 33, and the second sensor 51 detects the second protrusion 50 provided on the second crank large gear 42. The rotation drive is corrected while detecting. A sensor (not shown) that detects the reference point of the cylindrical plate cylinder 3 is also provided. And the said control is performed based on the detection information detected by the said sensor.

  In the double speed printing mode, these two first and second piston pumps 27 and 36 are driven, but in normal printing, only the first piston pump 27 is driven. The compressed air discharge timing of the first piston pump 27 is set so as to be an optimal position for peeling the front end of the printing paper in normal printing. The compressed air discharge timing of the first piston pump 27 is the same in the double speed printing mode.

  In the example shown in FIG. 3, the air delivery of the first piston pump 27 and the second piston pump 36 is combined downstream of the first and second check valves 45, 46, and the nozzle of the common paper discharge claw member 19 is combined. 20 is discharged. On the other hand, separate delivery pipes may be provided and discharged from the two paper discharge claw members 19, respectively. Alternatively, one discharge claw member 19 may be provided, and two nozzles 20 may be provided and discharged separately from the two nozzles 20.

  FIG. 4 is an explanatory diagram showing the relationship between the printing pressure and the discharge pressure corresponding to the state where the cylindrical plate cylinder 3 and the pre-made base paper 1 (normal master making master: stencil base paper) mounted thereon are developed. In the figure, the position of the printing paper 4 in the normal printing mode in the case of A3 paper printing (the figure (a)), the printing pressure range of the press roller 5 (the figure (b)), and the discharge claw member 19 The relationship between the compressed air pressure level of the air discharged from the nozzle 20 ((c) of the figure) is shown.

  In the same figure, the printing pressure by the press roller 5 is controlled to be turned on at a position corresponding substantially to the front end 4 f of the printing paper 4 and to be turned off at a position substantially corresponding to the rear edge 4 e of the printing paper 4. The compressed air pressure of the air discharged from the nozzle 20 of the paper discharge claw member 19 peaks when the front end 4f of the printing paper 4 passes through the printing nip 5a by controlling the rotation timing of the first piston pump 27. The value comes to come. When the first piston 29 starts to push air by the crank operation, the air pressure in the piston cylinder gradually increases and discharge starts from the nozzle 20 at a predetermined value or more, and then the air pressure rises and air discharge from the nozzle 20 Power is also increased. When the rotation of the first crank large gear 33 changes from pushing (forward movement) of the first piston 29 to pulling (reverse movement), air inflow from the first one-way valve 31 starts and air discharge force from the nozzle 20. Becomes zero at a stretch. The graph of FIG. 4C shows the discharge state of the compressed air. In the normal printing mode, the second piston pump 36 is not driven. Note that the symbol AR indicates a plate making area for forming an image.

  FIG. 5 is a diagram illustrating the relationship between the printing pressure and the discharge pressure corresponding to the state in which the cylindrical plate cylinder 3 and the pre-made base paper 1 (two-side master making master: stencil base paper) mounted thereon are unfolded in the double speed printing mode. FIG. FIG. 5 shows a state in which the cylindrical plate cylinder 3 and the stencil sheet (stencil sheet) 1 mounted on the cylindrical plate cylinder 3 are developed as in the example of FIG. 4, but this time, two sheets are printed in the double speed printing mode. In the case of printing on A4 paper, the positions of the printing papers 4a and 4b (FIG. 1A), the printing pressure range of the press roller 5 (FIG. 2B), and the nozzle 20 of the paper discharge claw member 19 are discharged. The relationship with the compressed air pressure level of the air ((c) in the figure) is shown.

  Even in the double speed printing mode, the printing pressure by the press roller 5 is turned on at a position corresponding to substantially the front end 4af of the first printing paper 4a, and at a position corresponding to the rear end 4be of the second printing paper 4b. It becomes OFF. This is because the printing pressure range is designed to be the same as that in the normal printing mode. However, since there is an interval of about 20 to 30 mm between the first image plate-making area AR1 and the second image plate-making area AR2, in the normal printing mode, the printing pressure extends from the rear end 4e of the A3 sheet (see FIG. 4) to the rear. Will take.

  On the other hand, the compressed air pressure of the air discharged from the nozzle 20 of the paper discharge claw member 19 controls the rotation timing of the first piston pump 27, so that the front end 4af of the first printing paper 4a passes through the printing nip 5a. A peak value (FIG. 5: first peak PK1) comes to the extent that it passes. This is the same as in the normal print mode. Further, in the case of the double speed printing mode, by driving the second piston pump 36 and controlling the rotation timing, a peak value (approximately in the drawing) when the leading end 4bf of the second printing paper 4b passes through the printing pressure nip 5a. 5: Air is discharged from the nozzle 20 so that the second peak PK2) comes. In the double speed printing mode, the discharge of the discharge claw member 19 from the nozzle 20 is thus performed twice while the cylindrical plate cylinder 3 rotates once. FIG.5 (c) is a graph which shows the discharge state of this compressed air.

  FIG. 6 is a block diagram illustrating a control configuration of the stencil printing apparatus according to the present embodiment. The stencil printing apparatus SPR in this embodiment includes a main body central control device 52, which communicates with the operation panel 53, transmits a plate making control command to the plate making device 55, and supplies paper to the paper feeding / conveying device 56. Send a paper control command. Further, reading information is input from the document reading device 54 to the main body central control device 52, and rotation position information is input from the plate cylinder rotation position sensor 57. Furthermore, the main body central control device 52 transmits a conveyance control command to the belt suction conveyance device. Position information is input from the first sensor 49 and the second sensor 51 to the main body central control device 52, and the main body central control device 52 drives and controls the first pump motor 35 and the second pump motor 44.

  In the operation panel 53, the “normal printing mode” 53a is selected as a standard. When the print image size is A4 or less and high speed printing is desired in a short time, the “double speed printing mode” 53b is selected from the operation panel 53. As a result, the image read by the document reading device 54 is made by the plate making device 55 so as to be arranged in two on one stencil sheet 1 in accordance with an instruction from the main body central control device 52. Then, the stencil sheet 1 made of the plate is mounted on the outer periphery of the cylindrical plate cylinder 3. In FIG. 6, it is the normal plate making master that is made by one-side plate making with the plate making device 55, and the two-side plate making master is made by two-side plate making.

  When a printing start key (not shown) is pressed from the operation panel 53, in the double speed printing mode, the main body central control device 52 controls the paper feeding / conveying device 56 and the cylindrical plate cylinder 3, and 1 of the cylindrical plate cylinder 3 is controlled. Two sheets of printing paper 4 are continuously fed per rotation.

  On the other hand, the first pump motor 35 of the first piston pump 27 is driven and controlled, and the discharged paper peeling air of the first printing paper 4 a is discharged from the nozzle 20. At this time, the rotation position of the first crank large gear 33 is corrected with reference to the first sensor 49 based on the detection signal output from the plate cylinder rotation position detection sensor 57 that detects the rotation position of the cylindrical plate cylinder 3. To control the driving of the first pump motor 35. In the case of the double speed printing mode, the second pump motor 44 of the second piston pump 36 is driven and controlled, and the discharge air for discharging the second printing paper 4b is discharged from the nozzle 20. Also at this time, the second pump motor 44 is corrected by correcting the rotational position of the second crank large gear 42 with reference to the second sensor 51 with reference to the detection signal output from the rotational position detection sensor 57 of the cylindrical plate cylinder 3. Control the drive. The belt suction and conveyance device 14 sucks and conveys the print paper 4 peeled off by the paper discharge peeling air and the paper discharge claw member 19 at the nip 5a, and the main body central control device 52 rotates the perforated belt 17 at this time. The drive and the air suction operation of the air suction device 18 are controlled.

  The main body central control device 52 includes a CPU. The CPU includes a control unit and a calculation unit, the control unit controls the interpretation of instructions and the control flow of the program, and the calculation unit executes the calculation. The program is stored in a memory (not shown), an instruction to be executed (a certain numerical value or a sequence of numerical values) is taken out from the memory in which the program is placed, and the program is executed. That is, the control by the main body central controller 52 is substantially executed by the CPU.

  FIG. 7 shows a printing pressure and a discharge pressure corresponding to a state in which a cylindrical plate cylinder 3 and a stencil sheet (stencil sheet) 1 attached to the cylindrical plate cylinder 3 are developed in the stencil printing apparatus SPR according to the second embodiment. It is explanatory drawing which shows these relationships.

  In the “normal printing mode”, it is not necessary to operate the second piston pump 36 originally. However, even in normal printing, the printing paper 4 is thin and stiff, so there is a solid image at the top of the printing paper 4, or there is an upper curl in which the end side of the printing paper 4 is rolled up above the center side. In this case, a trouble that the printing paper 4 does not peel off while being wound around the cylindrical plate cylinder 3 is likely to occur. Therefore, in this embodiment, the second piston pump 36 is also operated to increase the total amount of compressed air discharged from the paper discharge claw member 19 and / or the discharge time.

  In the present embodiment, the main body central controller 52 also drives the second piston pump 36 when the “strong discharge mode” is further selected in the normal printing mode. At that time, the second piston pump 36 is driven at a timing slightly delayed from the first piston pump 27. As a result, the compressed air CA1 from the first piston pump 27 and the compressed air CA2 from the second piston pump 36 are combined as shown in FIG. As a result, the compressed air CA3 becomes stronger and the discharge time can be kept longer. In this case, the rotational drive is corrected while the second sensor 51 detects the second protrusion 50 provided on the second crank large gear 42 in FIG. At that time, the timing can be shifted by providing a reference time interval after the second protrusion 51 is detected by the second sensor 51.

  Note that when the “normal printing mode” 53a is selected as the “strong discharge mode”, a selection screen is further displayed on the operation panel 53, and the user selects from the screen. Other parts not specifically described are configured in the same manner as in the first embodiment and function in the same manner.

  FIG. 8 shows a printing pressure and a discharge pressure corresponding to a state in which a cylindrical plate cylinder 3 and a stencil sheet (stencil sheet) 1 mounted on the cylindrical plate cylinder 3 are developed in the stencil printing apparatus SPR according to the third embodiment. It is explanatory drawing which shows these relationships. In the figure, the positions of the first and second printing papers 4-1 and 2 in the case of A3 paper printing in the normal printing mode (the figure (a)) and the printing pressure range of the press roller 5 (the figure). (B)), the compressed air pressure level of air from the first piston pump 27 discharged from the nozzle 20 of the paper discharge claw member 19 (FIG. 5C), and the compressed air pressure of air from the second piston pump 36. The relationship between the levels ((d) in the figure) is shown.

  As described above, in the “normal printing mode”, it is not necessary to operate the second piston pump 36 originally. However, even in normal printing, if the printing speed becomes high, the driving speed of the first piston pump 27 may not be able to follow the rotational speed of the cylindrical plate cylinder 3 in some cases. Conventionally, if the printing speed is up to about 120 sheets / minute, it can be handled by a piston pump driving device having a relatively small dedicated motor.

  However, if the printing speed is 150 sheets / minute, 180 sheets / minute, or 200 sheets / minute, the current motor becomes impossible, and it is necessary to newly drive with a motor having a large power. When a motor with high power is used in this way, the motor size increases, so that it may be impossible to install in space, and power consumption also increases. In any case, the initial cost and running cost increase, and it is not possible to cope with the current situation where energy saving is required.

  In order to cope with this, in the present embodiment, in the normal printing mode, if the printing speed is 120 sheets or less, the first piston pump 27 is driven, and if a speed exceeding this is selected, This can be done by alternately driving the first piston pump 27 and the second piston pump 36. Specifically, the first piston pump 27 is driven during the first printing (FIG. 8C), and the second piston pump 36 is driven during the second printing (FIG. 8D). In printing, the first piston pump 27 is driven again (FIG. 8C). In this way, the first and second piston pumps 27 and 36 do not necessarily have to follow the speed of the cylindrical plate cylinder 3, respectively, and if the cylindrical plate cylinder 3 is rotated twice, the next timing can be met. It will be good.

  However, in this case, in order to match the air pressure peak timings CA1pk and CA2pk, it is necessary to switch the operation timing of the first and second piston pumps 27 and 36 in terms of control.

  Other parts not specifically described are configured in the same manner as in the first embodiment and function in the same manner.

  FIG. 9 is a diagram illustrating a schematic configuration of a printing unit of the digital stencil printing apparatus according to the fourth embodiment.

  In the present embodiment, a sheet feeding / conveying device 56 is illustrated with respect to the first embodiment. In FIG. 9, the illustration of the nozzle 20 near the tip of the paper discharge claw member 19 is omitted, but it is installed in the same manner as in the first embodiment. Since the other parts are configured in the same manner as the printing part of the digital stencil printing apparatus according to the first embodiment shown in FIG. 1, the same reference numerals are given to the parts that can be regarded as the same or the same, and the overlapping description is omitted. Omitted.

  The paper feeding / conveying device 56 conveys the printing paper 4 set in the paper feeding tray 56d by rotating the pickup roller 56a and the paper feeding / feeding roller 56b, and feeds the printing paper 4 one by one so as not to be double fed by the separation pad 56c. It is designed to be transported separately.

  The printing paper 4 thus transported is sent to the printing pressure nip 5a through the registration roller section 9 in the same manner as in the first embodiment, and printing is performed.

  FIG. 9 shows a state immediately after the front end 4f of the printing paper 4 is pressed against the cylindrical plate cylinder 3 by the press roller 5 and printing is started. In this state, in order to peel the printing paper 4 that has passed through the printing pressure nip 5a from the cylindrical plate cylinder 3, the leading end of the paper discharge claw member 19 approaches the cylindrical plate cylinder 3, and the paper discharge claw member is further removed. The compressed air is discharged from the nozzle 20 in the vicinity of the tip 19 as in the first embodiment.

  FIG. 10 shows a state in which printing on the first printing paper 4a is completed (immediately before starting printing on the second printing paper 4b) in the double speed mode. 2 is substantially the same as the printing unit PRP shown in FIG.

  FIG. 11 is an operation explanatory view showing the operation of the registration roller unit 9. In the registration roller unit 9, the front end of the printing paper 4 is abutted against the nip 6 a between the registration roller lower 6 and the upper 7 and waits for an instruction from the main body central controller 52. The main body central controller 52 drives the lower registration roller 6 at a timing so that the image leading edge of the stencil sheet 1 mounted on the cylindrical plate cylinder 3 and the printing start position of the printing paper 4 coincide.

  In FIG. 11A, the lower registration roller 6 and the upper registration roller 7 are in a rotation stop state, and the printing paper 4 is conveyed from the paper feeding / conveying device 56 side. It collides with the nip 6a in between, and further conveys a certain amount. As a result, a predetermined deflection 4t is formed, and is temporarily stopped at that time.

  From this state, the registration roller lower 6 is driven to rotate at the timing when the leading position of the image and the image printing start position of the printing paper 4 coincide with the rotation of the cylindrical plate cylinder 3, and the printing paper 4a is directed toward the printing unit PRP. Sent out. The upper registration roller 7 rotates following the rotation of the lower registration roller 6. The sent printing paper 4a is conveyed as it is, and eventually becomes in the state of FIG. When the trailing edge 4ae of the printing paper 4a passes through the nip 6a, the rotational driving of the lower registration roller 6 is immediately stopped and the next printing paper 4b is waited for.

  However, when stopping the upper upper and lower registration rollers 6 and 7 that are rotating at high speed, a predetermined time is required until the upper and lower resist rollers 6 and 7 are stopped. When the upper and lower registration rollers 6 and 7 completely stop, the front end 4bf of the printing paper 4b collides with the nip 6a. Thereafter, a predetermined amount is further conveyed to form a predetermined deflection 4t, and the state shown in FIG. Similarly, the lower registration roller 6 is driven to rotate, and the printing paper 4b is sent out toward the printing unit PRP.

  However, as shown in FIG. 11C, when the second printing paper 4b is sent out, the rear end 4ae of the first printing paper 4a has already been conveyed and moved forward. An interval H between the trailing edge 4ae of the second printing paper 4a and the second printing paper 4bf is increased. This interval H becomes larger as the sheet conveyance speed, that is, the rotational speed of the cylindrical plate cylinder 3 increases. Since this interval H is equal to the gap (image interval) between the two plate-making images G1 and G2 made on the stencil sheet 1, the plate cylinder size of the cylindrical plate cylinder 3 and the stencil sheet size of the stencil sheet 1 are determined. In consideration, it is desirable to set the interval H as small as possible.

  FIG. 12 is an explanatory diagram showing the relationship between the stencil sheet and the image when the image is made on the stencil sheet.

  FIG. 12A shows a state where the first side plate-making image G1 and the second side plate-making image G2 are made on the stencil sheet 1 side by side. In the figure, the outlines of the first and second printing papers 4a and 4b corresponding to the first and second side plate-making images G1 and G2 are indicated by dotted lines. Each paper size is A4, and the image size is also the size corresponding to A4. In other words, this is a case where the print image exists on almost the entire surface of the A4 paper size. Here, the sheet interval H1 between the first and second printing sheets 4aA4 and 4bA4 affects the speed correspondence of the upper and lower sheet feed rollers 6,7. Since the image size for the printing paper 4aA4 and 4bA has a margin part, the image interval H2 between the first side plate-making image G1 and the second side plate-making image G2 is more marginal than the sheet interval H1 between the printing sheets 4aA4 and 4bA4. It becomes larger by taking into account.

  On the other hand, there are various paper sizes used for printing. In the double speed printing mode, when the maximum allowable paper is A4 size, for example, B5 size paper smaller than A4 may be used. is there.

  FIG. 12B shows a case where the printing papers 4a and 4b are B5 size. In this case, the image interval H2 between the first side plate-making image G1 and the second side plate-making image G2 with respect to the stencil sheet size can be increased as compared with the case of A4 size paper. Judged from the figure. Therefore, when the paper size detection device detects the length of the print paper 4 set in the paper feed tray 56d in the transport direction, and the result is smaller than the length of the A4 paper in the transport direction, the image interval H2 is set accordingly. The plate-making image position is controlled by the plate-making device 55 so as to increase. This makes it possible to perform double speed mode printing at a higher speed than with A4 paper. At this time, the rotational drive control of the upper and lower registration rollers 6 and 7 of the second printing paper 4b is basically the same as in FIG. That is, also in this case, since the image size for the printing paper 4aB5 and 4bB5 has a margin, the image interval H2 between the first side plate-making image G1 and the second side plate-making image G2 is the paper interval between the printing sheets 4a and 4b. It becomes larger than H1 by taking the margin part into consideration.

  Other parts not specifically described are configured in the same manner as in the first embodiment and function in the same manner.

  In the fourth embodiment, when the maximum allowable sheet is A4 size in the double speed printing mode, for example, the B5 size printing sheet 4 smaller than A4 may be used. In this case, the common sense is as shown in FIG. 12 (b), but the position of the second side plate-making image G2 on the stencil sheet 1 can be moved further rearward. This is shown in FIG. FIG. 13 is an explanatory diagram showing the relationship between the stencil sheet 1 and the images G1 and G2 when an image is made on the stencil sheet 1 in the fifth embodiment. Example 5 is also a modification of the case of FIG.

  When the printing paper 4 is B5 size, the image interval H2 between the first side plate-making image G1 and the second side plate-making image G2 can be set larger than in the case of FIG. This is because the image-forming area of the second plate-making image G2 can be moved backward as the plate-making image area length becomes shorter. In this way, it is possible to increase the sheet interval H1 by delaying the delivery timing of the second B5 printing sheet 4bB5.

  Therefore, when the paper size detection device detects the length of the printing paper 4 set in the paper feed tray 56d in the transport direction, and the result is smaller than the length of the A4 paper in the transport direction, the second side plate-making image G2 is detected. The formation position is moved to the end of the stencil sheet 1 at the rear end of the stencil sheet. This movement is performed under the control of the plate making device 55. That is, the control device (not shown) of the plate making device 55 sets the plate making image position so that the image interval H2 is increased to the position of the plate making area rear end.

  Thus, by increasing the image interval H2, it is possible to perform the double speed mode printing at a higher speed than in the case of FIG. In this case, what is important is that the rotation driving of the upper and lower registration rollers 6 and 7 of the second printing paper 4bB5 of B5 is also controlled to be delayed in accordance with this, so that the paper interval H1 is also increased. is there.

  Other parts not specifically described are configured in the same manner as in the first or fourth embodiment and function in the same manner.

  For example, even in the case of A4 paper, which is the maximum paper that can be used in the double speed mode, the interval dimension H can be reduced depending on the image. In actual printing, the image size is generally smaller than the paper size, and in particular, margins are often provided at the edges. For an image on A4 size paper, for example, a binding margin is provided. This is a margin considering the case where the printed product is stapled on the left side or punched. In the sixth embodiment, the space dimension H is increased by using the margin.

  FIG. 14 is a diagram illustrating an effective image area for an A4 sheet size according to the sixth embodiment.

  14A shows a case where the effective image area VAR for the A4 paper size 4aA4 is small and a binding margin margin BL1 is provided. FIG. 14B shows that the image itself is smaller than the paper and the image-free margin BL2 on the right side. An example of each is shown below. In this way, when there are margins BL1, 2, the plate is made by rotating the image so that the side where the margins BL1, 2 are located is the rear side (downstream side) with respect to the sheet conveyance direction. Thus, by making full use of the effective plate making area VAR of the stencil sheet 1 and moving the image position backward, the sheet interval H1 can be made larger than the standard.

  FIG. 15 is a diagram showing a state of plate making when such A4 paper has such margins.

  In the case shown in FIG. 14A, if the image is made so that the binding margin BL1 is on the back side in making the stencil sheet 1, the corresponding position of the printing paper 4b on the second side corresponding to that amount. Can be moved rearward (downstream in the transport direction), and as a result, the dimension H1 can be increased.

  14B, the first image plate-making area GARS1 remains as it is as shown in FIG. 15, but the upstream side of the cylindrical plate cylinder 3 in the rotational direction, in other words, after the first sheet. The second image plate-making area GARS2 for printing on the second printing paper 4a to be printed is moved to the end of the effective plate-making area VARS of the stencil sheet 1. Thereby, the position of the second sheet 4bA4 with respect to the stencil sheet 1 can be moved backward. In this embodiment, the lengths of the first image plate-making area GARS1 and the second image plate-making area GARS2 are determined by the conveyance speed in the sub-scanning direction and a predetermined reference point of the plate-making area when the stencil sheet 1 is conveyed during platemaking. It is calculated from the transit time. In this case, the CPU of the plate making apparatus 55 calculates the width dimension in the transport direction by calculation from the transport speed of the stencil sheet 1 and the passage time. Therefore, the measuring means referred to in the claims corresponds to the CPU of the plate making apparatus 55.

  As a result, the sheet interval H1 can be made larger than the standard as a result, so that the feeding timing of the printing paper 4b on the second surface is delayed by a corresponding amount as in the fifth embodiment. Control to be.

  In this way, there is a margin between the sheets, so that stencil printing can be performed in the double speed printing mode even at a higher speed. In this case, the rear end 4be of the printing paper 4bA4 on the second surface may protrude from the stencil sheet 1, but no particular problem arises because the protruding portion becomes a blank portion.

  In the sixth embodiment, in the double speed printing mode, if the sheet interval H1 is a standard 20 to 30 mm, the maximum allowable rotational speed of the cylindrical plate cylinder 3 is 90 rpm (180 sheets / min). If the value is 40 mm, it is possible to 120 rpm (240 sheets / min), and if the sheet interval H1 is 50 mm, it is possible to 135 rpm (270 sheets / min).

  FIG. 16 is a block diagram showing a control configuration of the stencil printing apparatus in the present embodiment.

  In this embodiment, instead of the first and second pump motors 35 and 44 and the first and second sensors 49 and 51, an image processing (image margin measurement) device 58, for the control configuration shown in FIG. The printing pressure control device 59, the paper size detection device 60, and the paper trailing edge detection sensor 26 are provided. Other parts are the same as those in FIG.

  Although the description partially overlaps with FIG. 6, the “normal print mode” 53 a is selected by default on the operation panel 53. When the print image size is A4 or less and the print paper size is A4 or less, and high-speed printing is desired in a short time, the “double speed printing mode” 53b is selected. Then, the image data read by the document reading device 54 is sent to the plate making device 55 via the main body central control device 52, and the plate making device 55 makes the plate making control so that two sides are arranged on one stencil sheet 1. The stencil sheet 1 is mounted on the outer periphery of the cylindrical plate cylinder 3. When the print start key is pressed on the operation panel 53, in the double speed printing mode, the main body central control device 52 controls the paper feeding / conveying device 56 to make two print sheets 4a per one rotation of the cylindrical plate cylinder 3. , 4b are sent continuously.

  The document image read by the document reading device (scanner) 54 is obtained by the image processing device 58 for the length in the sheet conveying direction. When the obtained length is a predetermined value, for example, 190 mm or less, there is a margin of 20 mm or more with respect to the sheet length of 210 mm. Move to and make the plate. In this case, since the margin is 20 mm or more, the movement amount can also be moved by 20 mm or more correspondingly.

  The sheet feeding / conveying device 56 feeds the first printing sheet 4a, and when the sheet trailing edge detection sensor 26 detects the passage of the sheet 4a at the trailing edge of the sheet 4a (see FIG. 2), immediately below the registration roller upper 6 , 7 is stopped. Then, the leading end 4bf of the second (second side) printing paper 4b collides with the nip 6a, and the paper feeding is stopped when a predetermined deflection amount is formed. Next, the paper trailing edge detection sensor 26 detects the trailing edge 4be of the second printing paper 4b, and after the preset time T1, the lower registration roller 6 is rotated again to send out the second printing paper 4b.

  When the print paper size is B5, the main body central controller 52 controls the time after the paper trailing edge detection sensor 26 detects the trailing edge of the printing paper 4bB5 to be T2 which is larger than T1. . Further, when the A4 sheet is moved by the image margin BL2, a time T3 corresponding to the moving amount is determined.

  FIG. 17 is a timing chart showing the sheet conveyance drive control timing of the sheet conveying apparatus 56. The horizontal axis represents time, and the vertical axis represents the rotation speed of the registration roller and the rotation speed of the registration roller.

  In the paper feeding operation of the paper feeding / conveying device 56, first, the first (first side) printing paper 4 a is fed and conveyed together with the upper registration roller 7 by rotationally driving the lower registration roller 6. Before the leading edge 4af of the first printing paper 4a collides with the nip 6a of the upper and lower registration rollers 6, 7, the speed is once reduced and further conveyed. As a result, the leading edge 4af of the printing paper 4a collides with the nip 6a of the upper and lower registration rollers 6 and 7 at timing c.

  After the timing c, the lower registration roller 6 is accelerated and driven at a predetermined timing point d determined by the position of the cylindrical plate cylinder 3. Thereby, the printing paper 4a is sent toward the printing unit PRP. Thereafter, the first (first surface) printing paper 4a is transported at a speed matching the printing section speed. When the trailing edge detection sensor 26 detects the trailing edge 4ae of the printing sheet 4a (timing e), the rotational driving of the lower registration roller 6 is immediately stopped immediately.

  When the margin time T3 has passed from the timing f when the rotation of the lower registration roller 6 stops, the leading edge 4bf of the second (second surface) printing paper 4b collides with the nip 6a of the upper and lower registration rollers 6 and 7. Then, the lower registration roller 6 is driven to feed and convey the printing paper 4b. Thereafter, the printing paper 4b is further conveyed to form a deflection 4t, and stops at timing g.

  When the margin time T4 has passed from the timing g, the lower registration roller 6 is accelerated and driven to feed the second printing paper 4b toward the printing unit PRP. During this time, the first printing paper 4a advances without stopping, so there is necessarily a gap between the trailing edge 4ae of the first printing paper 4a and the leading edge 4bf of the second printing paper 4b. This sheet interval H1 coincides with the image interval H2 between the first-side image G1 and the second-side plate-making image G2 made on the stencil sheet 1.

  If an attempt is made to further increase the printing speed, it takes time to stop the first printing paper 4a, and the characteristics shown by the dotted line in FIG. 17 are obtained. Therefore, it is necessary to delay the start of conveyance of the second side printing paper 4b, and the image interval H2 between the first side plate-making image G1 and the second side plate-making image G2 to be made on the stencil sheet 1 is also increased. There is a need.

  However, if the margins BL1 and BL2 of the image area AR printed on the printing paper 4 can be utilized as in the present embodiment and the position of the printing paper 4b on the second side can be moved backward, FIG. As shown by the dotted line in FIG.

  Other parts not specifically described are configured in the same manner as in the first and fourth embodiments and function in the same manner.

  As described above, according to the present embodiment, the following effects can be obtained. In the following description of the effects in the embodiment, each component in the present embodiment is indicated by parentheses in each claim or attached with a reference symbol to clarify the correspondence between the two.

1) A stencil printing apparatus SPR (stencil printing apparatus) according to the present embodiment is basically a cylindrical plate cylinder 3 in which a normal stencil master in which one image is stenciled on one stencil sheet 1 is mounted. A normal printing mode in which one printing paper 4 is fed and printed with respect to rotation, and a cylindrical plate cylinder on which a two-side plate making master in which two images are made side by side on one stencil sheet 1 is mounted. A double-speed printing mode in which two printing papers 4a and 4b are continuously fed and printed on the two sheets for one rotation of 3 is set as a printing control mode. Compressed air is supplied from the first piston pump 27 (first compressed air supply means) between the printing paper 4 and the outer peripheral surface of the cylindrical plate cylinder 3 at a timing corresponding to the position of the front end 4f of the printing paper 4. The printing paper 4 is peeled from the outer peripheral surface, and the double speed In the printing mode, similarly to the supply of compressed air in the normal printing mode, the first printing paper 4a is peeled off from the outer peripheral surface, and at the timing corresponding to the position 4bf of the second printing paper 4b. Compressed air is supplied from the second piston pump 36 (second compressed air generating means) between the second printing paper 4b and the outer peripheral surface of the cylindrical plate cylinder 3, and the second printing paper 4b is removed from the second printing paper 4b. The paper discharge claw member 19 that peels from the outer peripheral surface is provided.

  As described above, the compressed air for peeling is supplied from the first and second piston pumps 27 and 36 in correspondence with the positions of the leading ends 4af and 4bf of the first printing paper 4a or the second printing paper 4b. It is possible to increase the speed of stencil printing while preventing the paper from being rolled up.

2) The stencil printing apparatus SPR (stencil printing apparatus) according to the present embodiment basically feeds the printing paper 4 to the cylindrical plate cylinder 3 on which the stencil base paper 1 is mounted, and the fed printing paper 4 Is pressed against the cylindrical plate cylinder 3 which is driven to rotate, and a printing part PRP (printing means) for forming an image, the printing paper 4 on which an image is formed by the printing part PRP (printing means), and the cylindrical plate cylinder 3 The paper discharge claw member 19 (peeling means) that peels the printing paper 4 from the outer peripheral surface by discharging compressed air between the paper discharge peripheral member and the paper discharge claw member 19 (peeling means). A cylindrical plate cylinder having an air suction belt type paper discharge conveying device 14 (conveying means) for conveying the printing paper 4 and a normal master making master in which one image is made on one stencil sheet 1 Normally, one sheet of printing paper 4 is fed and printed for each rotation of Two printing sheets 4a and 4b are continuously fed for one rotation of the cylindrical printing cylinder in which the printing mode and the two-side plate making master on which two images are made side by side are mounted on one sheet of paper. Then, the double speed printing mode for printing on the two sheets is set as the print control mode, and further, the first and second piston pumps 27 and 36 (compressed air generating means) for generating the compressed air, the first and the first First and second air exhaust systems AS1, AS2 (compressed air supply) that join compressed air generated by two piston pumps 27, 36 (compressed air generating means) and supply them to the paper discharge claw member 19 (peeling means). In the normal printing mode, the first piston pump 27 (first compressed air generating means) is driven at a timing corresponding to the position of the leading edge 4f of the first printing paper 4 in the normal printing mode, and the double speed printing In this mode, the first piston pump 27 (first compressed air generating means) is driven at a timing corresponding to the position of the leading edge 4f of the first printing paper 4, and the position of the leading edge 4f of the second printing paper 4 is set. The second piston pump 36 (second compressed air generating means) is driven at a timing corresponding to the above, and the paper discharge claw member 19 is supplied from the first and second air exhaust systems AS1, AS2 (compressed air supply means). It is comprised so that it may supply to (peeling means).

  With this configuration, it is possible to increase the speed of the stencil printing while preventing the printing paper from being rolled up.

  More specifically, even in the double speed printing mode in which printing is performed at a double speed, not only the first printing paper 4a but also the second printing paper 4b tip 4bf is peeled off, the amount required for paper discharge peeling. The compressed air can be discharged from the paper discharge claw member 19. As a result, it is possible to prevent the occurrence of a problem that the second printing paper 4b is rolled up. Since the second piston pump is not driven during normal printing, wasteful power consumption can be reduced. It has the effect.

With regard to the separation of the second sheet in the double speed printing mode, it is possible to optimally set the timing of discharging compressed air from the sheet discharge claw, and the cylindrical plate cylinder when the second printing sheet 4b is discharged. Thus, the occurrence of the so-called paper discharge roll-up phenomenon can be prevented.

3) Either the normal printing mode or the double speed printing mode can be selected from the operation panel 53 (mode selection unit) of the stencil printing apparatus SPR, and the normal panel is operated by the operation panel 53 (operation mode selection unit). When the printing mode is selected, the first piston pump 27 (first compressed air generating means) and the second piston pump (second compressed air generating means) for each rotation of the cylindrical plate cylinder 3. ) Are alternately driven, even in the case of a user with a high normal printing rate, excessive load is not applied only to the first piston pump 27, and the life of the first piston pump 27 can be extended.

4) When printing in the normal printing mode, when the printing speed is equal to or lower than a preset speed, the first piston pump 27 (first compressed air generating means) is provided for each rotation of the cylindrical plate cylinder 3. Is driven once, and when the printing speed exceeds the preset speed, the first piston pump 27 (first compressed air generating means) and the first piston cylinder 27 are rotated every time the cylindrical plate cylinder 3 rotates. Since the two-piston pump 36 (second compressed air generating means) is driven alternately, the first piston pump 27 is driven synchronously even when the rotational speed of the cylindrical plate cylinder 3 is increased due to high-speed printing. Therefore, it is not necessary to make the first pump motor 35 specially large, and space saving, cost reduction, and energy saving can be achieved. In addition, since this structure is equipped with the 2nd piston pump 36 for double speed printing mode, it can drive alternately by using this and can respond also to high speed.

5) In the case of printing in the normal printing mode, an operation panel 53 (function selection means) for selecting a strong discharge mode (strong discharge function) is further provided, and the strong discharge mode (function selection means) is selected from the operation panel 53 (function selection means). When the powerful exhaust function is selected, the second piston pump 36 (second compressed air generating means) is set in advance with respect to the first piston pump 27 (first compressed air generating means). The second piston pump is used even when the printing paper is thin and stiff even during normal printing, there is a solid image at the top of the printing paper, or there is an upper curl in the printing paper. 36 is also operated to increase the total amount of compressed air discharged from the paper discharge claw member 19 or the discharge time, thereby preventing the paper discharge roll-up phenomenon from occurring.

6) The first and second compressed air generating means drive the first and second piston pumps 27 and 36 and the first and second piston pumps 27 and 36, respectively. 35 and 44 (first and second pump drive motors), it is possible to generate and supply compressed air with a conventionally known configuration.

7) A plate cylinder rotation position sensor 57 for detecting the rotation position of the cylindrical plate cylinder 3 is provided, and the first and second pump motors 35 and 44 (first and second pump drive motors) are the plate cylinders. Since it is driven in synchronism with the rotation of the cylindrical plate cylinder 3 based on the position detection signal from the rotational position sensor 57, the discharge from the first piston pump 27 and the discharge from the second piston pump 36 are independently performed. Each can be set to drive. Thereby, the freedom degree of the supply timing of compressed air can be raised. Further, since the cylindrical plate cylinder 3 is synchronized with the rotation of the cylindrical plate cylinder 3, the compressed air can be supplied without shifting the discharge timing while the first and second pump motors 35 and 44 are driven independently.

8) having a first check valve 45, having a first compressed air delivery pipe 30 for delivering compressed air sent from the first piston pump 27, and a second check valve 46; A second compressed air delivery pipe 39 for discharging the compressed air sent out from the two-piston pump 36, and the compressed air from the first and second compressed air discharge pipes 30, 39 are joined together to form the discharge claw member 19 (exfoliation means) is provided with a common air exhaust pipe 47 (compressed air supply pipe), so two piston pumps are required, but the common air delivery pipe 47, the discharge claw member 19, and the nozzle 20 Can be completed with a common one. Thereby, cost reduction and space saving can be achieved. Further, since the first and second check valves 45 and 46 are provided in the first compressed air delivery pipe 30 and the second compressed air delivery pipe 39, respectively, the first check valves 45 and 46 provide the first check valve 45 and 46, respectively. It is possible to prevent the compressed air from the piston pump 27 from flowing as it is toward the second piston pump 36 or vice versa. Thereby, the air pressure of compressed air does not decrease.

9) In the stencil printing apparatus SPR having the basic configuration shown in the above 1) or 2), the feeding tray 56d that feeds the printing paper 4 and the transport direction of the printing paper 4 fed from the feeding tray 56d An image processing device 58 (detection means) for detecting the length, and when the transport direction length of the printing paper 4 is shorter than a preset length, the stencil paper 1 is placed in the double speed printing mode. The image interval between the first side plate-making image G1 and the second side plate-making image G2 of the two-side image to be made is made according to the conveyance direction length of the paper size detected by the image processing device 58 (detection means). Since the main image controller 52 sets the first image interval larger than a preset standard value, when the paper size is smaller than the allowable maximum size, the feeding timing of the printing paper 4b on the second side The standard value It becomes possible to delay Ri. As a result, there is a margin in the timing of paper feeding from the paper feeding / conveying device 56, and the paper feeding quality of the printing paper corresponding to the plate-making image G2 on the second surface is improved without increasing the length of the stencil paper 1. And stabilize. As a result, printing can be performed at a higher speed than in the case of the maximum paper size.

10) Since the image interval H2 is set to a second image interval that is larger than the first image interval, and the feeding timing of the second printing paper 4b is delayed from a preset standard value, the paper size Is smaller than the maximum allowable size, it is possible to move the plate-making image position of the plate-making image G2 on the second surface backward from the standard. Thereby, the sending-out timing of the printing paper 4b on the second surface can be further delayed than in the case of 9). As a result, there is a further margin in the timing of paper feeding from the paper feeding / conveying device 56, and printing can be performed at a higher speed than in the case of 9).

11) In the stencil printing apparatus SPR having the basic configuration shown in 1) or 2 above, at least the image on the downstream side in the rotational direction of the cylindrical plate cylinder 3 among the two-side images made on the stencil sheet 1 in the double speed printing mode. The main body central control device 52 (measurement means) for calculating (measuring) the effective image length in the rotation direction of the cylindrical plate cylinder 3 is calculated (measured) by the main body central control device 52 (measurement means). When the effective image length VAR is shorter than a preset length, image plate-making is performed such that the side where the margins BL1 and BL2 of the image area AR with respect to the print paper 4 are formed is on the upstream side in the paper transport direction. An image interval H2 between the first surface plate-making image G1 and the second surface plate-making image G2 of the surface image is set in advance according to the length calculated (measured) by the main body central control device 52 (measurement means). Since the first image interval larger than the standard value is set, even if the paper size is the same as the allowable maximum size, the effective image length VAR in the transport direction is equal to or less than a preset length. It is possible to increase the paper interval H1 between the first side printing paper 4a and the second side printing paper 4b. As a result, even if the length of the stencil sheet 1 is not increased, the feeding quality of the printing paper 4b corresponding to the second side plate-making image G2 is improved and stabilized. As a result, printing can be performed at a higher speed than in the case of the maximum paper size.

12) The image interval H2 is set to a second image interval that is larger than the first image interval, and the feeding timing of the second printing paper 4b is set in advance according to the second image interval. Therefore, when the paper size is smaller than the allowable maximum size, the plate-making image position of the plate-making image G2 on the second surface is moved backward from the standard according to the second image interval. Is possible. Thereby, the delivery timing of the printing paper 4b on the second surface can be further delayed than in the case of 11). As a result, there is a further margin in the timing of paper feeding from the paper feeding / conveying device 56, and printing can be performed at a higher speed than in the case of 11).

  Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention, and all the technical matters included in the technical idea described in the claims are all included. The subject of the present invention. The above-described embodiments show preferred examples, but those skilled in the art can realize various alternatives, modifications, variations, and improvements from the contents disclosed in the present specification. These are included in the technical scope described in the appended claims.

1 Stencil paper (normal master making, double master making)
DESCRIPTION OF SYMBOLS 3 Cylindrical plate cylinder 4,4a, 4b Printing paper 4f, 4af, 4bf Tip 14 Air suction belt type conveying apparatus 19 Paper discharge claw member 20 Nozzle 27 First piston pump 30 First compressed air discharge pipe 35 First pump motor 36 Second piston pump 39 Second compressed air discharge pipe 44 Second pump motor 45 First check valve 46 Second check valve 47 Common air delivery pipe 52 Main body central control unit 53 Operation panel 56d Paper feed tray 57 Plate cylinder Rotational position sensor 58 Image processing device AS1 First air exhaust system AS2 Second air exhaust system BL1, BL2 Blank G1 (First surface) Plate-making image G2 (Second surface) Plate-making image H1 Paper interval H2 Image interval PRP Printing unit SPR digital stencil printing machine (stencil printing machine)
VAR Effective image length

JP 2002-29133 A JP 2006-212982 A JP-A-2005-212210

Claims (13)

A normal printing mode in which one printing sheet is fed and printed for one rotation of a cylindrical plate cylinder in which a normal plate making master on which one image is made on one stencil sheet is mounted, and one sheet Double speed that feeds two sheets of paper continuously for one rotation of a cylindrical plate cylinder on which a two-side master making machine in which two images are made side by side on a stencil sheet is printed. In the stencil printing apparatus in which the printing mode is set as the printing control mode,
In the normal printing mode, compressed air is supplied from the first compressed air supply means between the printing paper and the outer peripheral surface of the cylindrical plate cylinder at a timing corresponding to the position of the leading edge of the first printing paper. Peeling the printing paper from the outer peripheral surface;
In the double-speed printing mode, the first printing paper is peeled from the outer peripheral surface in the same manner as the compressed air supply in the normal printing mode, and at the timing corresponding to the position of the leading edge of the second printing paper. Separating means for separating the second printing paper from the outer peripheral surface by supplying compressed air from the second compressed air generating means between the second printing paper and the outer peripheral surface of the cylindrical plate cylinder is provided. A stencil printing apparatus characterized by that. A printing unit that feeds printing paper to a cylindrical plate cylinder on which a stencil sheet is mounted, and presses the fed printing paper against the rotationally driven cylindrical plate cylinder to form an image; and
A peeling means for discharging compressed air from the outer peripheral surface by discharging compressed air between the printing paper image-formed by the printing means and the outer peripheral surface of the cylindrical plate cylinder;
Conveying means for conveying the printing paper peeled by the peeling means;
Have
A normal printing mode in which one printing sheet is fed and printed for one rotation of a cylindrical plate cylinder in which a normal plate making master on which one image is made on one stencil sheet is mounted, and one sheet Double speed that feeds two sheets of paper continuously for one rotation of a cylindrical plate cylinder on which a two-side master making machine in which two images are made side by side on a stencil sheet is printed. In the stencil printing apparatus in which the printing mode is set as the printing control mode,
First and second compressed air generating means for generating the compressed air;
Compressed air supply means for joining compressed air generated by the compressed air generating means and supplying the compressed air to the peeling means;
With
In the normal printing mode, the first compressed air generating means is driven at a timing corresponding to the position of the leading edge of the first printing paper,
In the double speed printing mode, the first compressed air generating means is driven at a timing corresponding to the position of the leading edge of the first printing paper, and the first timing at a timing corresponding to the position of the leading edge of the second printing paper. 2 compressed air generating means is driven,
A stencil printing apparatus, wherein the stencil printing apparatus is supplied from the compressed air supply means to the peeling means. In the stencil printing apparatus according to claim 1 or 2,
Comprising mode selection means for selecting one of the normal printing mode and the double speed printing mode;
When the normal printing mode is selected by the mode selection means, the first compressed air generating means and the second compressed air generating means are alternately driven every rotation of the cylindrical plate cylinder. A stencil printing apparatus characterized by that. In the stencil printing apparatus according to claim 1 or 2,
When printing in the normal printing mode, when the printing speed is equal to or lower than a preset speed, the first compressed air generating means is driven once for each rotation of the cylindrical plate cylinder, and the printing speed is When the preset speed is exceeded, the first compressed air generating means and the second compressed air generating means are alternately driven every rotation of the cylindrical plate cylinder. apparatus. In the stencil printing apparatus according to claim 1 or 2,
In the case of printing in the normal printing mode, further comprising a function selection means for selecting a powerful discharge function,
When the powerful discharge function is selected by the function selecting means, the second compressed air generating means is driven with a delay with respect to the first compressed air generating means by a preset phase difference. Stencil printing device. In the stencil printing apparatus according to any one of claims 1 to 5,
The first and second compressed air generating means include first and second piston pumps and first and second pump drive motors for driving the first and second piston pumps, respectively. Stencil printing device. In the stencil printing apparatus according to claim 6,
A plate cylinder rotation position sensor for detecting the rotation position of the cylindrical plate cylinder;
The stencil printing apparatus, wherein the first and second pump drive motors are driven in synchronization with rotation of the cylindrical plate cylinder based on a position detection signal from the plate cylinder rotation position sensor. In the stencil printing apparatus according to claim 6 or 7,
A first compressed air delivery pipe having a first check valve and delivering compressed air delivered from the first piston pump;
A second compressed air delivery pipe having a second check valve for discharging compressed air sent out from the second piston pump;
A compressed air supply pipe that joins compressed air from the first and second compressed air discharge pipes and supplies the compressed air to the peeling means;
A stencil printing apparatus comprising: In the stencil printing apparatus according to claim 1 or 2,
A paper feed tray for feeding the printing paper;
Detecting means for detecting a length in a conveying direction of printing paper fed from the paper feeding tray;
With
When the transport direction length of the printing paper is shorter than a preset length, a space between the first side plate-making image and the second side plate-making image of the two-side image to be made on the stencil sheet in the double speed printing mode. The stencil printing apparatus is characterized in that the image interval is set to a first image interval that is larger than a standard value set in advance in accordance with the transport direction length of the paper size detected by the detecting means. In the stencil printing apparatus according to claim 9,
The stencil printing apparatus, wherein the image interval is set to a second image interval that is larger than the first image interval, and the feeding timing of the second printing paper is delayed from a preset standard value . In the stencil printing apparatus according to claim 1 or 2,
A measuring means for measuring an effective image length in a rotation direction of the cylindrical plate cylinder of at least a second side plate-making image among the two-side images made on the stencil sheet in the double speed printing mode;
When the effective image length measured by the measuring unit is shorter than a preset length, image plate making is performed such that the side where the margin of the image area with respect to the printing paper is formed is upstream in the paper conveyance direction, The image interval between the first surface plate-making image and the second surface plate-making image of the two-surface image is set to a first image interval larger than a standard value set in advance according to the length measured by the measuring means. A stencil printing apparatus. In the stencil printing apparatus according to claim 11,
The image interval is set to a second image interval that is larger than the first image interval, and the second printing paper feed timing is set to a standard value set in advance according to the second image interval. A stencil printing apparatus characterized by being delayed further. A printing unit that feeds printing paper to a cylindrical plate cylinder on which a stencil sheet is mounted, and presses the fed printing paper against the rotationally driven cylindrical plate cylinder to form an image; and
A peeling means for discharging compressed air from the outer peripheral surface by discharging compressed air between the printing paper image-formed by the printing means and the outer peripheral surface of the cylindrical plate cylinder;
Conveying means for conveying the printing paper peeled by the peeling means;
First and second compressed air generating means for generating the compressed air;
Compressed air supply means for joining compressed air generated by the compressed air generating means and supplying the compressed air to the peeling means;
As a printing control mode, a stencil printing apparatus having
A normal printing mode in which one printing sheet is fed and printed for one rotation of a cylindrical plate cylinder in which a normal plate making master on which one image is made on one stencil sheet is mounted, and one sheet Double-speed printing mode in which two sheets of paper are continuously fed and printed on the two sheets per rotation of a cylindrical plate cylinder on which a two-side plate-making master with two images lined up on the base paper is mounted Is set,
A stencil printing method for stencil printing by the stencil printing apparatus,
Driving the first compressed air generating means at a timing corresponding to the position of the leading edge of the first printing paper in the normal printing mode;
In the double speed printing mode, the first compressed air generating means is driven at a timing corresponding to the position of the leading edge of the first printing paper, and the second timing is corresponding to the position of the leading edge of the second printing paper. Driving the compressed air generating means of
Supplying compressed air generated in each step from the compressed air supply means to the peeling means;
A stencil printing method comprising: