JP2010162744A - Printing pressure regulating apparatus and printing pressure regulating method, and offset printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To always keep a dot gain optimal according to a change in the diameter of a blanket cylinder. <P>SOLUTION: This printing pressure regulating apparatus 20 applied to a printing section which makes an ink fed to the printing plate P of a plate cylinder 8 transferred to the blanket B of the blanket cylinder 9 as a printed image, and regulates printing pressure between the printing plate P and the blanket B includes: a plate cylinder moving means 21 which moves the plate cylinder 8 in a configuration that the inter-axial distance D1 between the plate cylinder 8 and the blanket cylinder 9 is changed; and a controlling means 23 which controls the plate cylinder moving means 21 according to the relationship of the change in the diameter of the blanket cylinder 9 accompanied by the progress of printing which has been stored in advance. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing pressure adjusting device, a printing pressure adjusting method, and an offset printing machine that can always maintain an optimum dot gain.

  An offset sheet-fed printing machine serving as an offset printing machine prints on a sheet as printing paper, and includes a paper feeding unit, a printing unit, and a paper discharge unit. The sheets are stacked on the paper feed tray in the paper feed unit and sent to the printing unit. Subsequently, the sheet sent out by the paper feeding unit is subjected to predetermined printing in the printing unit. Subsequently, the sheets printed by the printing unit are stacked on the paper discharge tray while being conveyed by the chain gripper mechanism in the paper discharge unit, and are discharged.

  An offset rotary printing press as an offset printing press performs printing on a web that is printing paper, and includes a paper feeding unit, a printing unit, a turn bar device, and a folding machine. The web is provided as a winding paper in the paper feeding unit, pulled out from the winding paper, and continuously sent out to the printing unit. Subsequently, the web sent out by the paper feeding unit is subjected to predetermined printing in the printing unit. Subsequently, the web printed by the printing unit is overlapped in a predetermined order after the travel route is changed in plural in the turn bar device. Subsequently, the web overlapped by the turn bar device is vertically folded by a folding machine and then laterally cut by a predetermined length, and further folded to form a fold and is discharged.

  In the printing section of such an offset printing machine, ink is supplied from the ink application roller of the ink supply device to the printing plate mounted on the outer periphery of the plate cylinder, and this ink is applied to the outer periphery of the blanket cylinder by the image line portion of the printing plate. While being transferred as a printed image to the rolled blanket, it is transferred as a pattern from the blanket cylinder to the printing paper.

  In such an offset printing machine, the quality of printing performed on the printing paper is determined by the printing pressure between the printing plate of the plate cylinder and the blanket of the blanket cylinder. This printing pressure affects the dot gain (the amount of dot thickening) when dots (halftone dots) forming an image are transferred from the printing plate to the blanket.

  In conventional offset printing machines, the characteristics of dot gain due to differences in material properties such as the hardness of the blanket, the hardness of the ink, and the paper thickness of the printing paper are found, and the plate cylinder and the blanket cylinder are determined according to the physical properties of the material. Is set so that the printing pressure between the plate cylinder and the blanket cylinder is always kept optimal (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 4-327941

  However, since the outermost diameter of the blanket cylinder (hereinafter referred to as the blanket cylinder diameter) decreases with time as printing is performed, the printing pressure is set according to the physical properties of the above materials. Even if this is done, the reproducibility of the dots is impaired as the printing progresses. For this reason, it is desired to always keep the dot gain optimal in accordance with the change in the diameter of the blanket cylinder.

  The present invention solves the above-described problems, and provides a printing pressure adjustment device, a printing pressure adjustment method, and an offset printing machine that can always maintain an optimum dot gain according to a change in the diameter of a blanket cylinder. Objective.

  In the printing pressure adjusting apparatus of the present invention for achieving the above object, the ink supplied to the printing plate of the plate cylinder is applied to a printing unit for transferring the printing image to the blanket of the blanket cylinder as a printing image, In a printing pressure adjusting device that adjusts the printing pressure between the blanket cylinder and a blanket, a plate cylinder moving means for moving the plate cylinder in a manner that changes an inter-axis distance between the plate cylinder and the blanket cylinder; Control means for controlling the plate cylinder moving means based on the relationship of the change in the diameter of the blanket cylinder with the progress of the stored printing.

  According to this printing pressure adjusting device, even if the diameter of the blanket cylinder decreases with the progress of printing, the printing pressure at which the printing plate and the blanket come into contact is properly maintained, so that the dot gain can always be kept optimal. . That is, it is not necessary to tailor each time the diameter of the blanket cylinder decreases. Furthermore, even if the printing plate is used in another printing apparatus, it is possible to set an appropriate printing pressure by utilizing the relationship of the change in the diameter of the blanket cylinder as the printing progresses. Can print with the same color depth.

  In the printing pressure adjusting apparatus according to the present invention, the plate cylinder moving means moves an eccentric bearing that supports a rotating shaft of the plate cylinder.

  According to this printing pressure adjusting device, the plate cylinder can be moved so that the distance between the axes of the plate cylinder and the blanket cylinder changes.

  In the printing pressure adjusting apparatus of the present invention, the plate cylinder moving means forms a contact surface of a plate cylinder bearer disposed on the plate cylinder as an inclined surface inclined with respect to the axis of the plate cylinder, and the blanket The contact surface of the blanket cylinder bearer disposed on the cylinder is formed as an inclined surface inclined with respect to the axis of the blanket cylinder, and the inclined surfaces are in contact with each other. It is characterized by being moved along the axis.

  According to this printing pressure adjusting device, the plate cylinder can be moved so that the distance between the axes of the plate cylinder and the blanket cylinder changes.

  In the printing pressure adjustment method of the present invention for achieving the above object, the ink supplied to the printing plate of the plate cylinder is applied to a printing unit for transferring the printing image to the blanket of the blanket cylinder as a printing image, In the printing pressure adjustment method for adjusting the printing pressure between the blanket cylinder and the blanket, a step of acquiring a change amount of the diameter of the blanket cylinder with the progress of printing, and then, based on the acquired change amount And a step of changing an inter-axis distance between the plate cylinder and the blanket cylinder.

  According to this printing pressure adjustment method, even if the diameter of the blanket cylinder decreases with the progress of printing, the printing pressure at which the printing plate and the blanket come into contact is properly maintained, so that the dot gain can always be kept optimal. .

  In the offset printing machine of the present invention for achieving the above object, in the offset printing machine comprising a printing unit for transferring the ink supplied to the printing plate of the plate cylinder to the blanket of the blanket cylinder as a printed image, the printing unit And any one of the above-mentioned printing pressure adjusting devices is applied.

  According to this offset printing machine, since the dot gain is always kept optimal by applying the printing pressure adjusting device, high-quality printing can be maintained.

  According to the present invention, even when the diameter of the blanket cylinder decreases with the progress of printing, the printing pressure at which the printing plate and the blanket come into contact with each other is properly maintained, so that the dot gain can always be kept optimal.

FIG. 1 is a schematic configuration diagram of an offset printing machine according to a first embodiment of the present invention. FIG. 2 is a schematic configuration diagram of the printing pressure adjustment apparatus according to the first embodiment of the present invention. FIG. 3 is a schematic configuration diagram of a printing pressure adjusting apparatus according to the second embodiment of the present invention.

  Embodiments of a printing pressure adjusting device, a printing pressure adjusting method, and an offset printing machine according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

[Embodiment 1]
FIG. 1 is a schematic configuration diagram of an offset printing press according to an embodiment of the present invention.

  As shown in FIG. 1, the offset printing machine according to the present embodiment performs printing on a sheet S such as a film, art paper, or coated paper in addition to paper for normal use. 1 is a so-called offset sheet-fed printing press 1 provided with an impression cylinder 10.

  The offset sheet-fed printing press 1 includes a paper feeding unit 2 that feeds out and feeds printing sheets S one by one, a printing unit 3 that performs printing on the sheet S conveyed along the traveling direction R, and printing. And a sheet discharge unit 4 that discharges the sheet S subjected to.

  The paper feed unit 2 includes a paper feed stand 5 and a paper feed mechanism 6. The paper feed table 5 is used for stacking and placing sheets S. The paper feed mechanism 6 picks up and supplies the sheets S stacked on the paper feed tray 5 one by one in order from the top, and uses a separator (paper suction), a cam, a swing gripper, etc., which are not explicitly shown in the figure. It is configured. The sheet feeding stand 5 is controlled to move upward in the vertical direction corresponding to the supply of the sheet S so that the sheet feeding mechanism 6 maintains a substantially constant positional relationship with the sheet S.

  The printing unit 3 includes a plurality of printing units 7 that print different colors to realize color printing. A plurality of printing units 7 are provided along the traveling direction R of the sheet S for each color to be printed. In the offset sheet-fed printing press 1, for example, four printing units 7 respectively corresponding to four different colors such as cyan, magenta, yellow, and black are provided.

  Each printing unit 7 includes a plate cylinder 8, a blanket cylinder 9, and an impression cylinder 10. The plate cylinder 8, the blanket cylinder 9 and the impression cylinder 10 are formed in a cylindrical shape, and each axis is horizontal and is provided so as to intersect the traveling direction R. The plate cylinder 8, the blanket cylinder 9 and the impression cylinder 10 are arranged in this order from the upper side to the lower side in the vertical direction, and the outer peripheral surfaces of the plate cylinder 8 and the blanket cylinder 9 are in contact with each other. The outer peripheral surface of the body 10 is provided so as to be in contact with each other. The plate cylinder 8, the blanket cylinder 9, and the impression cylinder 10 are provided so as to be rotatable about their respective axis centers.

  The plate cylinder 8 is provided with a printing plate P (see FIGS. 2 and 3) for forming a printed image on the peripheral surface thereof. In each printing unit 7, an ink supply device (not shown) including a group of rollers for supplying ink to the image line portion of the printing plate P and a dampening solution to supply a non-image line portion of the printing plate P A dampening device (not shown) comprising a group of water rollers is provided around the plate cylinder 8. A blanket B (see FIGS. 2 and 3) formed of an elastic material is attached to the peripheral surface of the blanket cylinder 9. The ink supplied to the image line portion of the plate cylinder 8 is transferred to the blanket B. Then, the blanket cylinder 9 transfers ink to the sheet S using the print image of the printing plate P as a pattern. The impression cylinder 10 applies a predetermined printing pressure to the sheet S in cooperation with the blanket cylinder 9. The impression cylinder 10 is a so-called double cylinder having a diameter twice as large as that of the plate cylinder 8 and the blanket cylinder 9, and a clamping mechanism 101 (see FIG. 2) that holds the front end of the sheet S around the circumference. It is provided at two locations on the circumferential surface at substantially symmetrical positions with respect to the axial center of the impression cylinder 10.

  Each printing unit 7 further includes an intermediate cylinder 11. The intermediate cylinder 11 is formed in a cylindrical shape like the plate cylinder 8, the blanket cylinder 9 and the impression cylinder 10, and its axis is horizontal and intersects with the traveling direction R. It is rotatably provided as a center. The intermediate cylinder 11 is disposed on the upstream side of the impression cylinder 10 with respect to the traveling direction R of the sheet S, and is provided so as to contact the outer peripheral surface of the impression cylinder 10. Similarly to the impression cylinder 10, the intermediate cylinder 11 is a double cylinder having a diameter twice that of the plate cylinder 8 and the blanket cylinder 9, and a clamping mechanism (not shown) that holds the leading end of the sheet S around the intermediate cylinder 11. Are provided at two locations on the circumferential surface at substantially symmetrical positions with respect to the axis of the intermediate cylinder 11.

  In each printing unit 7, the intermediate cylinder 11 is disposed so as to be in contact with the impression cylinder 10 of the printing unit 7 adjacent to the upstream side in the traveling direction R of the sheet S. In this embodiment, as shown in FIG. 1, only the printing unit 7 located on the most upstream side in the traveling direction R does not have the double cylinder size intermediate cylinder 11 on the upstream side of paper conveyance. The structure in which the impression cylinder 10 conveys the paper from the paper feeding unit 2 through a single cylinder type intermediate cylinder is adopted. The sheet S supplied from the paper supply unit 2 is first supplied between the blanket cylinder 9 and the impression cylinder 10 of the printing unit 7 located on the most upstream side, and then the downstream printing unit 7. By being replaced by the respective clamping mechanisms from the intermediate cylinder 11 to the impression cylinder 10, it is conveyed through each printing unit 7, and ink is transferred one after another on the way. The type and arrangement of the impression cylinder 10 and the intermediate cylinder 11 are not limited to this, and can be appropriately changed according to the required transport path design.

  The paper discharge unit 4 conveys and stacks the sheets S printed by the printing unit 3 in an aligned state. The paper discharge unit 4 includes a chain gripper 12 that conveys the sheet S, a paper discharge tray 13 on which the printed sheets S are stacked, a fan device 14 that forms a downward airflow in the vicinity of the paper discharge tray 13, and a paper pad 16 And a vacuum suction wheel device 17, a rear paper aligning device 18, and a width direction paper aligning device 19.

  The chain gripper 12 constitutes a sheet conveying apparatus of the present invention that receives the sheet S from the impression cylinder 10 of the most downstream printing unit 7 and conveys the sheet S to a predetermined position above the sheet discharge table 13. The chain gripper 12 has an endless chain 121 facing the endless chain 121 that moves in a circulation path between a position adjacent to the impression cylinder 10 of the most downstream printing unit 7 and an upper position of the paper discharge tray 13. A gripper 122 having a claw portion (not shown) for clamping and releasing the sheet S is supported between the holding rod 121 and the holding rod.

  The paper discharge table 13 is suspended from a chain and configured to be movable in the vertical direction. The sheet discharge table 13 stacks and places the sheets S discharged from the chain gripper 12. When the top surface height of the uppermost stage rises as the sheets S are stacked, the discharge table 13 is continuously or stepwise vertically so that the falling distance of the sheets S becomes substantially constant. It is controlled to move downward in the direction.

  The fan device 14 has a plurality of fans arranged in a substantially rectangular shape, and moves the sheet S discharged from the chain gripper 12 above the discharge table 13 downward in the vertical direction by airflow control. The vacuum suction wheel device 17 reduces the traveling speed when the sheet S is dropped and controls the dropping posture. The vacuum suction wheel device 17 brakes the sheet S by applying a suction force to the upstream (rear) end in the traveling direction R of the sheet S.

  The paper pad 16, the rear paper aligning device 18, and the width direction paper aligning device 19 are provided below the chain gripper 12 and above the paper discharge table 13, that is, between the chain gripper 12 and the paper discharge table 13. . The paper pad 16 regulates the downstream (front) position in the traveling direction R of the sheet S, and a plurality of the paper pads 16 are provided along the width direction of the sheet S. The rear paper aligning device 18 regulates the upstream (rear) position in the traveling direction R of the sheet S, and is composed of a plurality of plate-like members extending in the vertical direction, and is attached to the vacuum suction wheel device 17 respectively. It is done. The width direction paper aligning device 19 aligns the positions of the sheets S in the width direction.

  In the offset sheet-fed printing press 1 having the above-described configuration, the sheets S stacked on the paper feed tray 5 of the paper feed unit 2 are picked up one by one from the top by the paper feed mechanism 6, and the printing unit 7 of the print unit 3 is picked up. To be supplied. The sheets S supplied to the printing units 7 are sequentially transferred by the clamping mechanisms of the impression cylinders 10 and the intermediate cylinders 11 of the respective printing units 7, thereby being conveyed through the respective printing units 7. Transcribed. In each printing unit 7, water is supplied from the dampening device to the non-image area of the printing plate P attached to the peripheral surface of the plate cylinder 8, and then ink is supplied from the ink supply device to the image area of the printing plate P. Is done. The printed image on the printing plate P obtained in this way is transferred to the blanket cylinder 9. The printed image transferred to the blanket cylinder 9 is transferred to the sheet S conveyed by the impression cylinder 10 and printing of one color is performed. This is repeated in each printing unit 7 for color printing. The color-printed sheet S is replaced with the gripper 122 of the chain gripper 12 from the impression cylinder 10 of the last (most downstream side) printing unit 7. The sheet S conveyed by the chain gripper 12 is removed from above the paper discharge tray 13 and dropped, and is stacked on the paper discharge tray 13. At this time, in order to prevent undried ink from appearing on the back side of the upper sheet S, powder is sprayed on the sheet S in advance when it is conveyed by the chain gripper 12. Further, the sheets S stacked on the paper discharge tray 13 are aligned by the fan device 14, the vacuum suction wheel device 17, the paper pad 16, the rear paper alignment device 18, and the width direction paper alignment device 19 on the paper discharge tray 13. Laminated.

  FIG. 2 is a schematic configuration diagram of the printing pressure adjustment apparatus according to the first embodiment of the present invention. As shown in FIG. 2, the printing pressure adjusting apparatus 20 according to the first embodiment includes a plate cylinder moving unit 21, a blanket cylinder moving unit 22, and a control unit 23.

  The plate cylinder moving means 21 has an eccentric bearing 211, a link 212, a rotating disk 213, and a motor M1 as a drive source. The eccentric bearing 211 rotatably supports a rotating shaft 8b disposed around the axis 8a of the plate cylinder 8, and can rotate around an axis 211a that is eccentric with respect to the axis 8a of the plate cylinder 8. Is provided. One end of the link 212 is connected to the eccentric bearing 211 via the shaft 212a, and the other end is connected to a position away from the shaft center of the rotating disk 213 via the shaft 212b. The turntable 213 is provided to be rotatable around its own axis. The motor M1 is connected to the turntable 213 via a speed reduction mechanism (not shown), and drives the turntable 213 to rotate. The plate cylinder moving means 21 is provided on both ends of the rotary shaft 8b of the plate cylinder 8, respectively.

  In other words, the plate cylinder moving means 21 is driven by the motor M1 to rotate the rotating disk 213. As the rotating disk 213 rotates, the eccentric bearing 211 rotates about the axis 211a via the link 212. To do. As a result, the axis 8a of the plate cylinder 8 moves in parallel, and the distance between the axes of the plate cylinder 8 and the blanket cylinder 9 (the distance between the axes 8a and 9a of the plate cylinder 8 and the blanket cylinder 9) D1 changes. To do.

  The blanket cylinder moving means 22 includes an eccentric bearing 221, a link 222, a rotating disk 223, and a motor M2 as a drive source. The eccentric bearing 221 rotatably supports the rotation shaft 9b disposed around the shaft center 9a of the blanket cylinder 9, and is rotatable about an axis 221a that is eccentric with respect to the shaft center 9a of the blanket cylinder 9. Is provided. One end of the link 222 is connected to the eccentric bearing 221 via a shaft 222a, and the other end is connected to a position away from the shaft center of the rotating disk 223 via a shaft 222b. The turntable 223 is provided to be rotatable around its own axis. The motor M2 is connected to the rotating disk 223 via a speed reduction mechanism (not shown) and rotationally drives the rotating disk 223. The blanket cylinder moving means 22 is provided at both ends of the rotation shaft 9b of the blanket cylinder 9, respectively.

  That is, in the blanket cylinder moving means 22, the rotating disk 223 rotates when the motor M2 is driven, and the eccentric bearing 221 rotates around the shaft center 221a via the link 222 as the rotating disk 223 rotates. To do. As a result, the axis 9a of the blanket cylinder 9 moves in parallel, and the distance between the blanket cylinder 9 and the impression cylinder 10 (the distance between the axis 9a, 10a between the blanket cylinder 9 and the impression cylinder 10) D2 changes. To do.

  The control means 23 is composed of a microcomputer or the like. The control unit 23 includes a storage unit 231, a plate cylinder movement driving unit 232, and a blanket cylinder movement driving unit 233. The storage unit 231 includes a RAM, a ROM, and the like, and stores programs and data. The plate cylinder movement driving unit 232 drives the motor M1 of the plate cylinder moving means 21. For example, when a pulse motor is applied to the motor M1, the plate cylinder movement driving unit 232 outputs the number of pulses necessary for moving the plate cylinder 8 to the motor M1. The blanket cylinder movement drive unit 233 drives the motor M <b> 2 of the blanket cylinder movement means 22. For example, when a pulse motor is applied to the motor M2, the blanket cylinder movement drive unit 233 outputs the number of pulses necessary for moving the blanket cylinder 9 to the motor M2. Then, the control unit 23 controls the plate cylinder moving unit 21 and the blanket cylinder moving unit 22 in accordance with programs and data stored in the storage unit 231 in advance.

  The programs and data stored in the storage unit 231 are for driving the plate cylinder moving means 21 and the blanket cylinder moving means 22. The storage unit 231 stores data indicating that the diameter of the blanket cylinder 9 decreases with time according to the relationship of the change in the diameter of the blanket cylinder 9 with the progress of printing, that is, the number of sheets S printed. Further, in the storage unit 231, data on the number of pulses of the motor M <b> 1 that moves the plate cylinder 8 in order to properly maintain the printing pressure at which the printing plate P and the blanket B are in contact with the decrease in the diameter of the blanket cylinder 9. Is remembered.

  Here, the diameter of the blanket cylinder 9 refers to the outermost diameter including the blanket B when the blanket B is wound around the blanket cylinder 9. That is, the change in the diameter of the blanket cylinder 9 refers to the change in the surface diameter of the blanket B wound around the blanket cylinder 9.

  In addition, as a factor that the diameter of the blanket cylinder 9 decreases with time, in addition to the number of printed sheets S, the change of the blanket B itself with time, the frequency of the cleaning solvent when cleaning the blanket B, or the amount of cleaning solvent And there are differences in printing materials (type of blanket B, ink, etc.). That is, in the time-dependent change of the blanket B itself, the amount of change in the diameter of the blanket cylinder 9 can be defined according to the time elapsed since the blanket B was wound around the blanket cylinder 9. In addition, the frequency or amount of the cleaning solvent applied when cleaning the blanket B is such that the blanket B hurts the more the cleaning solvent is applied to the blanket B. Therefore, the blanket cylinder 9 depends on the frequency or amount of the cleaning solvent applied. The amount of change in diameter can be defined. In addition, as for the difference in printing materials, the amount of change in the diameter of the blanket cylinder 9 over time according to the difference in the type of the blanket B and the change in diameter of the blanket cylinder 9 over time according to the difference in ink that touches the blanket B. You can define the quantity.

  Then, the control means 23 acquires the necessary number of pulses for moving the plate cylinder 8 closer to the blanket cylinder 9 from the storage unit 231 in accordance with the number of printed sheets S, and the plate cylinder movement driving unit 232 acquires the number of pulses. Output to the motor M1. Then, the motor M1 is driven with the output number of pulses, and the plate cylinder 8 is moved closer to the blanket cylinder 9. As a result, even if the diameter of the blanket cylinder 9 decreases as the printing progresses, the printing pressure at which the printing plate P and the blanket B are in contact with each other is properly maintained, so that the dot gain is always kept optimal. become.

  In the storage unit 231, the change in the interaxial distance D <b> 1 associated with the movement of the blanket cylinder 9, i.e., data in which the interaxial distance D <b> 1 between the plate cylinder 8 and the blanket cylinder 9 changes due to the movement of the blanket cylinder 9. Is remembered. Further, in the storage unit 231, the plate cylinder 8 is moved in order to properly maintain the printing pressure at which the printing plate P and the blanket B are in contact with the change in the inter-axis distance D 1 according to the movement of the blanket cylinder 9. Data on the number of pulses of the motor M1 is stored. Furthermore, in order to press the sheet S properly between the blanket cylinder 9 and the impression cylinder 10 against the paper thickness of the sheet S, the hardness of the blanket B, the hardness of the ink, etc., the storage unit 231 has a blanket. Data on the number of pulses of the motor M2 that moves the cylinder 9 is stored.

  Then, when the paper thickness of the sheet S, the hardness of the blanket B, the hardness of the ink, or the like changes, the control means 23 moves the blanket cylinder 9 closer to the impression cylinder 10 in response to these changes. The number of pulses necessary for the separation movement is acquired from the storage unit 231 and is output to the motor M2 by the blanket cylinder movement driving unit 233. Then, the motor M2 is driven with the output number of pulses, and the blanket cylinder 9 is moved toward or away from the impression cylinder 10. As a result, even if the paper thickness of the sheet S, the hardness of the blanket B, the hardness of the ink, and the like change, the sheet S is always pressed properly between the blanket cylinder 9 and the impression cylinder 10.

  By the way, when the blanket cylinder 9 is moved in response to changes in the paper thickness of the sheet S, the hardness of the blanket B, the hardness of the ink, etc., the inter-axis distance D1 between the plate cylinder 8 and the blanket cylinder 9 changes. For this reason, the dot gain may be inappropriate. Therefore, when the blanket cylinder 9 is moved, the control means 23 stores the necessary number of pulses for moving the plate cylinder 8 toward or away from the blanket cylinder 9 from the storage unit 231 in response to the movement. Obtained and output to the motor M1 by the plate cylinder movement drive unit 232. Then, the motor M1 is driven with the output number of pulses, and the plate cylinder 8 is moved toward or away from the blanket cylinder 9. As a result, even if the blanket cylinder 9 moves, the printing pressure at which the printing plate P and the blanket B are in contact with each other is properly maintained, so that the dot gain is always kept optimal.

  As described above, according to the printing pressure adjusting apparatus 20 of the first embodiment, the printing plate P and the blanket B are brought into contact with each other based on the relationship of the change in the diameter of the blanket cylinder 9 with the progress of printing stored in advance. The movement of the plate cylinder 8 is controlled so as to maintain the printing pressure appropriately, and the inter-axis distance D1 with the blanket cylinder 9 is changed. As a result, even if the diameter of the blanket cylinder 9 decreases with the progress of printing, the printing pressure at which the printing plate P and the blanket B are in contact with each other is properly maintained, so that the dot gain can always be kept optimal. become. That is, it is not necessary to tailor the blanket cylinder 9 each time the diameter decreases. Furthermore, even if the printing plate P is used in another printing apparatus, it is possible to set an appropriate printing pressure by using the relationship of the change in the diameter of the blanket cylinder 9 as the printing progresses. It becomes possible to print with the same color intensity.

  Further, according to the printing pressure adjusting device 20 of the first embodiment, the printing plate P and the blanket B are moved in accordance with the change in the inter-axis distance D1 between the plate cylinder 8 and the blanket cylinder 9 as the blanket cylinder 9 moves. The inter-axis distance D1 is changed by controlling the movement of the plate cylinder 8 so that the printing pressure in contact is properly maintained. As a result, even if the inter-axis distance D1 changes as the blanket cylinder 9 moves, the dot gain can always be kept optimal.

  In the case where bearers (not shown) are provided in the plate cylinder 8 and the blanket cylinder 9, when the plate cylinder 8 is moved and the inter-axis distance D1 between the blanket cylinder 9 is reduced, the bearers come into contact with each other. It is conceivable that the movement of the plate cylinder 8 is hindered. In this case, the movement of the plate cylinder 8 can be allowed by changing the material so that the bearers can be deformed by pressing each bearer. In addition, the platen 8 is moved by reducing the load between the bearers so that the platen cylinder 8 can move the change in the diameter of the blanket drum 9 from the new time to the replacement of the blanket B (for example, 0.1 mm to 0.2 mm). The movement of the cylinder 8 can be allowed.

  In addition, according to the printing pressure adjustment method of the first embodiment, based on the step of acquiring the change amount of the diameter of the blanket cylinder 9 as the printing progresses, and then the acquired change amount of the diameter of the blanket cylinder 9. And a step of changing the inter-axis distance D1 between the plate cylinder 8 and the blanket cylinder 9 so that the printing plate P and the blanket B are brought into contact with each other with an appropriate printing pressure. As a result, even if the diameter of the blanket cylinder 9 decreases with the progress of printing, the printing pressure at which the printing plate P and the blanket B are in contact with each other is properly maintained, so that the dot gain can always be kept optimal. become.

  Further, according to the printing pressure adjustment method of the first embodiment, the step of acquiring the change amount of the inter-axis distance D1 accompanying the movement of the blanket cylinder 9, and then the acquired change amount of the inter-axis distance D1. And a step of changing the inter-axis distance D1 between the plate cylinder 8 and the blanket cylinder 9 so that the printing pressure at which the printing plate P and the blanket B are in contact with each other according to the movement of the blanket cylinder 9 is properly maintained. . As a result, even if the inter-axis distance D1 changes as the blanket cylinder 9 moves, the dot gain can always be kept optimal.

  Further, according to the offset printing machine of the first embodiment, since the dot gain is always kept optimal by applying the printing pressure adjusting device 20, high-quality printing can be maintained. .

[Embodiment 2]
FIG. 3 is a schematic configuration diagram of a printing pressure adjusting apparatus according to the second embodiment of the present invention.
As shown in FIG. 3, the printing pressure adjusting device 30 according to the first embodiment includes a plate cylinder moving unit 31, a blanket cylinder moving unit 32, and a control unit 33.

  The plate cylinder moving means 31 has a plate cylinder bearer 311, a link 312, a rotating disk 313, and a motor M 3 as a drive source. The plate cylinder bearer 311 is attached to a rotation shaft 8b arranged around the axis 8a of the plate cylinder 8 and is configured to rotate together with the plate cylinder 8, and moves along the extending direction of the axis 8a. It is provided as possible. The contact surface of the plate cylinder bearer 311 is formed as an inclined surface 311a inclined with respect to the axis 8a. One end of the link 312 is connected to the plate cylinder bearer 311, and the other end is connected to a position away from the axis of the rotating disk 313 via the shaft 312 b. One end of the link 312 is, for example, centered on the axis 8a so that the plate cylinder 8 does not rotate with the plate cylinder 8 via the plate cylinder bearer 311 when the plate cylinder 8 rotates about the axis 8a. It is connected to a plate cylinder bearer 311 via a bearing (not shown). The turntable 313 is provided to be rotatable around its own axis. The motor M3 is connected to the turntable 313 via a speed reduction mechanism (not shown), and rotates the turntable 313.

  In other words, the plate cylinder moving means 31 is driven by the motor M3 to rotate the rotating disk 313, and the rotation of the rotating disk 313 causes the plate cylinder bearer 311 to extend the axis 8a through the link 312. Move along the current direction. An inclined surface 311a of the plate cylinder bearer 311 is in contact with an inclined surface 321a formed on a contact surface of a blanket cylinder bearer 321 described later. As a result, along with the movement of the plate cylinder bearer 311, the axis 8 a of the plate cylinder 8 moves in parallel, and the distance between the axes of the plate cylinder 8 and the blanket cylinder 9 (the axis 8 a between the plate cylinder 8 and the blanket cylinder 9). , 9a) D1 changes. The plate cylinder bearers 311 are provided on both sides of the plate cylinder 8, and the plate cylinder moving means 31 is configured to move the plate cylinder bearers 311 at an equal distance.

  The blanket cylinder moving means 32 has a blanket cylinder bearer 321, a link 322, a rotating disk 323, and a motor M4 as a drive source. The blanket cylinder bearer 321 is attached to a rotation shaft 9b arranged around the axis 9a of the blanket cylinder 9 and is configured to rotate together with the blanket cylinder 9, and moves along the extending direction of the axis 9a. It is provided as possible. The contact surface of the blanket cylinder bearer 321 is formed as an inclined surface 321a inclined with respect to the axis 9a. The inclined surface 321 a is in contact with the inclined surface 311 a of the plate cylinder bearer 311. One end of the link 322 is connected to the blanket cylinder bearer 321 and the other end is connected to a position away from the axis of the rotating disk 323 via the shaft 322b. One end of the link 322 is, for example, centered on the axis 9a so that the blanket cylinder 9 does not rotate with the blanket cylinder 9 via the blanket cylinder bearer 321 when the blanket cylinder 9 rotates around the axis 9a. It is connected to a blanket cylinder bearer 321 via a bearing (not shown). The turntable 323 is provided to be rotatable around its own axis. The motor M4 is connected to the turntable 323 via a speed reduction mechanism (not shown), and drives the turntable 323 to rotate.

  That is, in the blanket cylinder moving means 32, the rotating disk 323 rotates when the motor M4 is driven, and the blanket cylinder bearer 321 extends through the link 322 along with the rotation of the rotating disk 323. Move along the current direction. The slope 321 a of the blanket cylinder bearer 321 is in contact with the slope 311 a of the contact surface of the plate cylinder bearer 311. As a result, the axial center 9a of the blanket cylinder 9 moves in parallel with the movement of the blanket cylinder bearer 321, and the distance between the axes of the blanket cylinder 9 and the impression cylinder 10 (the axis 9a between the blanket cylinder 9 and the impression cylinder 10). , 10a) D2 changes. The blanket cylinder bearer 321 is provided on both sides of the blanket cylinder 9, and the blanket cylinder moving means 32 is configured to move each blanket cylinder bearer 321 at an equal distance.

  The control means 33 is constituted by a microcomputer or the like. The control means 33 is provided with a storage unit 331, a plate cylinder movement driving unit 332, and a blanket cylinder movement driving unit 333. The storage unit 331 includes a RAM, a ROM, and the like, and stores programs and data. The plate cylinder movement drive unit 332 drives the motor M3 of the plate cylinder movement means 31. For example, when a pulse motor is applied to the motor M3, the plate cylinder movement driving unit 332 outputs the number of pulses necessary for moving the plate cylinder 8 to the motor M3. The blanket cylinder movement drive unit 333 drives the motor M4 of the blanket cylinder movement means 32. For example, when a pulse motor is applied to the motor M4, the blanket cylinder movement drive unit 333 outputs the number of pulses necessary for moving the blanket cylinder 9 to the motor M4. Then, the control means 33 comprehensively controls the plate cylinder moving means 31 and the blanket cylinder moving means 32 in accordance with programs and data stored in the storage unit 331 in advance.

  The programs and data stored in the storage unit 331 are for driving the plate cylinder moving means 31 and the blanket cylinder moving means 32. The storage unit 331 stores data indicating that the diameter of the blanket cylinder 9 decreases with time according to the relationship of the change in the diameter of the blanket cylinder 9 with the progress of printing, that is, the number of printed sheets S. Further, the storage unit 331 stores data on the number of pulses of the motor M3 that moves the plate cylinder 8 in order to properly maintain the printing pressure at which the printing plate P and the blanket B are in contact with the decrease in the diameter of the blanket cylinder 9. Is remembered.

  Here, the diameter of the blanket cylinder 9 refers to the outermost diameter including the blanket B when the blanket B is wound around the blanket cylinder 9. That is, the change in the diameter of the blanket cylinder 9 refers to the change in the surface diameter of the blanket B wound around the blanket cylinder 9.

  In addition, as a factor that the diameter of the blanket cylinder 9 decreases with time, in addition to the number of printed sheets S, the change of the blanket B itself with time, the frequency of the cleaning solvent when cleaning the blanket B, or the amount of cleaning solvent And there are differences in printing materials (type of blanket B, ink, etc.). That is, in the time-dependent change of the blanket B itself, the amount of change in the diameter of the blanket cylinder 9 can be defined according to the time elapsed since the blanket B was wound around the blanket cylinder 9. In addition, the frequency or amount of the cleaning solvent applied when cleaning the blanket B is such that the blanket B hurts the more the cleaning solvent is applied to the blanket B. Therefore, the blanket cylinder 9 depends on the frequency or amount of the cleaning solvent applied. The amount of change in diameter can be defined. In addition, as for the difference in printing materials, the amount of change in the diameter of the blanket cylinder 9 over time according to the difference in the type of the blanket B and the change in diameter of the blanket cylinder 9 over time according to the difference in ink that touches the blanket B. You can define the quantity.

  Then, the control means 33 acquires the necessary number of pulses for moving the plate cylinder 8 closer to the blanket cylinder 9 from the storage unit 331 according to the number of printed sheets S, and the plate cylinder movement drive unit 332 Output to the motor M3. Then, the motor M3 is driven with the output number of pulses, and the plate cylinder 8 is moved closer to the blanket cylinder 9. As a result, even if the diameter of the blanket cylinder 9 decreases as the printing progresses, the printing pressure at which the printing plate P and the blanket B are in contact with each other is properly maintained, so that the dot gain is always kept optimal. become.

  Further, the storage unit 331 stores the relationship of the change in the inter-axis distance D1 accompanying the movement of the blanket cylinder 9, that is, the data in which the inter-axis distance D1 between the plate cylinder 8 and the blanket cylinder 9 changes due to the movement of the blanket cylinder 9. Is remembered. Further, the storage cylinder 331 moves the plate cylinder 8 in order to properly maintain the printing pressure at which the printing plate P and the blanket B are in contact with the change in the inter-axis distance D1 according to the movement of the blanket cylinder 9. Data on the number of pulses of the motor M3 is stored. Furthermore, the storage unit 331 has a blanket for properly pressing the sheet S between the blanket cylinder 9 and the impression cylinder 10 against the paper thickness of the sheet S, the hardness of the blanket B, the hardness of the ink, and the like. Data on the number of pulses of the motor M4 that moves the cylinder 9 is stored.

  Then, when the paper thickness of the sheet S, the hardness of the blanket B, the hardness of the ink, or the like changes, the control means 33 moves the blanket cylinder 9 closer to the impression cylinder 10 in response to these changes. The number of pulses necessary for the separation movement is acquired from the storage unit 331, and is output to the motor M4 by the blanket cylinder movement driving unit 333. Then, the motor M4 is driven with the output number of pulses, and the blanket cylinder 9 is moved toward or away from the impression cylinder 10. As a result, even if the paper thickness of the sheet S, the hardness of the blanket B, the hardness of the ink, and the like change, the sheet S is always pressed properly between the blanket cylinder 9 and the impression cylinder 10.

  By the way, when the blanket cylinder 9 is moved in response to changes in the paper thickness of the sheet S, the hardness of the blanket B, the hardness of the ink, etc., the inter-axis distance D1 between the plate cylinder 8 and the blanket cylinder 9 changes. For this reason, the dot gain may be inappropriate. Therefore, when the control unit 33 moves the blanket cylinder 9, the number of pulses necessary for moving the plate cylinder 8 toward or away from the blanket cylinder 9 is stored in the storage unit 331 in response to the movement. Obtained and output to the motor M3 by the plate cylinder movement drive unit 332. Then, the motor M3 is driven with the output number of pulses, and the plate cylinder 8 is moved toward or away from the blanket cylinder 9. As a result, even if the blanket cylinder 9 moves, the printing pressure at which the printing plate P and the blanket B are in contact with each other is properly maintained, so that the dot gain is always kept optimal.

  As described above, according to the printing pressure adjusting device 30 of the second embodiment, the printing plate P and the blanket B are brought into contact with each other based on the relationship of the change in the diameter of the blanket cylinder 9 with the progress of printing stored in advance. The movement of the plate cylinder 8 is controlled so as to maintain the printing pressure appropriately, and the inter-axis distance D1 with the blanket cylinder 9 is changed. As a result, even if the diameter of the blanket cylinder 9 decreases with the progress of printing, the printing pressure at which the printing plate P and the blanket B are in contact with each other is properly maintained, so that the dot gain can always be kept optimal. become. That is, it is not necessary to tailor the blanket cylinder 9 each time the diameter decreases. Furthermore, even if the printing plate P is used in another printing apparatus, it is possible to set an appropriate printing pressure by using the relationship of the change in the diameter of the blanket cylinder 9 as the printing progresses. It becomes possible to print with the same color intensity.

  Further, according to the printing pressure adjusting device 30 of the second embodiment, the printing plate P and the blanket B are moved in accordance with the change in the inter-axis distance D1 between the plate cylinder 8 and the blanket cylinder 9 as the blanket cylinder 9 moves. The inter-axis distance D1 is changed by controlling the movement of the plate cylinder 8 so that the printing pressure in contact is properly maintained. As a result, even if the inter-axis distance D1 changes as the blanket cylinder 9 moves, the dot gain can always be kept optimal.

  Further, according to the printing pressure adjustment method of the second embodiment, the step of acquiring the amount of change in the diameter of the blanket cylinder 9 as the printing progresses, and the next step based on the acquired amount of change in the diameter of the blanket cylinder 9. And a step of changing the inter-axis distance D1 between the plate cylinder 8 and the blanket cylinder 9 so that the printing plate P and the blanket B are brought into contact with each other with an appropriate printing pressure according to the progress of printing. As a result, even if the diameter of the blanket cylinder 9 decreases with the progress of printing, the printing pressure at which the printing plate P and the blanket B are in contact with each other is properly maintained, so that the dot gain can always be kept optimal. become.

  Further, according to the printing pressure adjustment method of the second embodiment, the step of acquiring the change amount of the inter-axis distance D1 accompanying the movement of the blanket cylinder 9, and then the acquired change amount of the inter-axis distance D1. And a step of changing the inter-axis distance D1 between the plate cylinder 8 and the blanket cylinder 9 so that the printing pressure at which the printing plate P and the blanket B are in contact with each other according to the movement of the blanket cylinder 9 is properly maintained. . As a result, even if the inter-axis distance D1 changes as the blanket cylinder 9 moves, the dot gain can always be kept optimal.

  Further, according to the offset printing machine of the second embodiment, since the dot gain is always kept optimal by applying the printing pressure adjusting device 30, it is possible to maintain high quality printing. .

  In the first and second embodiments described above, the offset sheet-fed printing press that performs printing on one side of the sheet S as an offset printing press has been illustrated and described, but the present invention is not limited to this. For example, although not shown in the figure, the printing unit has a back side printing unit and a front side printing unit, and these printing units are arranged in series along the sheet traveling direction to print on the front and back sides of the printing paper. Even in a double-sided offset sheet-fed printing machine that performs printing, by applying the printing pressure adjustment devices 20 and 30, the dot gain is always kept optimal, so that high-quality printing can be maintained. .

  Also, for example, although not shown in the figure, a web that has been taken up by a paper feeder is sent out, printed on this web, and overlapped in a predetermined order after the travel routes of many webs are changed by a turn bar device. After that, the same applies to an offset rotary printing press in which a web is vertically folded by a folding machine and then horizontally cut by a predetermined length, and then folded to form a fold. In addition, the printing pressure adjusting devices 20 and 30 can be applied. In the case of an offset rotary printing press, the storage units 231 and 331 of the control means 23 and 33 store the blanket cylinder 9 according to the conveyance length of the printed web as the relationship of the change in the diameter of the blanket cylinder 9 with the progress of printing. Data for decreasing the diameter of the blanket cylinder 9 is stored. In this way, by applying the printing pressure adjusting devices 20 and 30 to the offset rotary printing press, the dot gain is always kept optimal, so that high quality printing can be maintained. Further, the offset rotary printing press includes a single-sided offset rotary printing press and a double-sided offset rotary printing press. In the case of a single-sided offset rotary printing press, a printing cylinder, a blanket cylinder, and an impression cylinder are provided. The adjusting devices 20 and 30 can be easily applied. On the other hand, a double-sided offset rotary printing press includes a plate cylinder and a blanket cylinder, and prints on the front and back surfaces with a web sandwiched between a pair of blanket cylinders. Therefore, in the double-sided offset rotary printing press, the blanket cylinder moving means is configured to move either one of the blanket cylinders. Further, even in a newspaper rotary offset printing press, similarly, by applying the printing pressure adjusting devices 20 and 30, the dot gain is always kept optimal, so that high quality printing can be maintained. It becomes possible.

  As described above, the printing pressure adjustment device and the printing pressure adjustment method according to the present invention are suitable for keeping the dot gain optimal at all times, and the offset gain to which this printing pressure adjustment device is applied is always optimal in dot gain. It is applied to sustain high-quality printing by being maintained at

1 Offset sheet-fed printing press (offset printing press)
DESCRIPTION OF SYMBOLS 2 Paper feed part 3 Printing part 4 Paper discharge part 5 Paper feed stand 6 Paper feed mechanism 7 Printing unit 8 Plate cylinder 8a Axis 8b Rotating shaft 9 Blanket cylinder 9a Axis 9b Rotating axis 10 Impression cylinder 10a Axis 10b Rotating axis 101 Clamping mechanism 20 Printing pressure adjusting device 21 Plate cylinder moving means 211 Eccentric bearing 211a Shaft center 212 Link 212a, 212b Shaft 213 Rotating disk 22 Blanket cylinder moving means 221 Eccentric bearing 221a Shaft center 222 Link 222a, 222b Shaft 223 Rotating disk 23 Control means 231 Storage unit 232 Plate cylinder movement drive unit 233 Blanket cylinder movement drive unit M1, M2 Motor P Printing plate B Blanket S Sheet R Traveling direction D1 Axis distance between plate cylinder and blanket cylinder D2 Between axes of blanket cylinder and impression cylinder Distance 30 Printing pressure adjusting device 31 Plate cylinder moving means 311 Plate cylinder bearer 31 a slope 312 link 312b shaft 313 rotating disk 32 blanket cylinder moving means 321 blanket cylinder bearers 321a slopes 322 link 322b shaft 323 rotating disk 33 the control unit 331 storage unit 332 print drum transfer drive unit 333 blanket cylinder transfer drive unit M3, M4 motor

Claims (5)

A printing pressure adjustment that adjusts the printing pressure between the printing plate of the plate cylinder and the blanket of the blanket cylinder, applied to a printing section that transfers the ink supplied to the printing plate of the printing cylinder to the blanket of the blanket cylinder as a printed image. In the device
A plate cylinder moving means for moving the plate cylinder in a manner of changing an inter-axis distance between the plate cylinder and the blanket cylinder;
Control means for controlling the plate cylinder moving means based on the relationship of changes in the diameter of the blanket cylinder with the progress of printing stored in advance;
A printing pressure adjusting device comprising:   2. The printing pressure adjusting apparatus according to claim 1, wherein the plate cylinder moving means moves an eccentric bearing that supports a rotation shaft of the plate cylinder.   The plate cylinder moving means forms a contact surface of a plate cylinder bearer arranged on the plate cylinder as an inclined surface inclined with respect to an axis of the plate cylinder, and a contact surface of a blanket cylinder bearer arranged on the blanket cylinder Is formed as an inclined surface inclined with respect to the axis of the blanket cylinder, and the inclined surfaces are in contact with each other, and the bearer of the plate cylinder is moved along the axis of the plate cylinder. The printing pressure adjusting device according to claim 1. A printing pressure adjustment that adjusts the printing pressure between the printing plate of the plate cylinder and the blanket of the blanket cylinder, applied to a printing section that transfers the ink supplied to the printing plate of the printing cylinder to the blanket of the blanket cylinder as a printed image. In the method
Obtaining the amount of change in the diameter of the blanket cylinder as the printing progresses;
Next, a step of changing an inter-axis distance between the plate cylinder and the blanket cylinder based on the obtained change amount;
The printing pressure adjustment method characterized by including. In an offset printing machine equipped with a printing unit that transfers the ink supplied to the printing plate of the plate cylinder to the blanket of the blanket cylinder as a printed image,
An offset printing machine, wherein the printing pressure adjusting device according to any one of claims 1 to 3 is applied to the printing unit.

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