JP2010253885A - Offset printing method and offset printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an offset printing method and an offset printing device which can perform high precision printing. <P>SOLUTION: A plate table 14 and a table for printing object 16 are set movably on a guide rail 12 of a trestle 11. A transfer mechanism section 19 is prepared in an intermediate part of the guide rail 12. A laser sensor 27 is prepared at the point of an upstream side of table travelling direction a at the time of printing relative to a blanket roll 20 of the transfer mechanism section 19. The surface height positions of the plate 13 on the plate table 14 and of the printing object 15 on the table for printing object 16 which approach under the blanket roll 20 are identified in advance by the laser sensor 27, and when the blanket roll 20 touches the plate 13 and the printing object 15, the apparent radius from the center of rotation of the blanket roll 20 to the parts which are in contact with the plate 13 and the printing object 15 is searched for from the difference between the height position e of the center of rotation of the blanket roll 20 and the predetermined surface height positions j of the plate 13 and the printing object 15, and the circumference movement amount drawn from the apparent radius and the angular velocity is synchronized to the movement amount of the plate 13 and the printing object 15. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an offset printing method and apparatus used for performing a fine print pattern on a print target with high printing accuracy as in the case of forming an electrode pattern on a substrate by printing.

  In recent years, as a method of forming an electrode pattern (conductive pattern) such as a liquid crystal display on a required substrate, a printing technique using a conductive paste as a printing ink instead of fine processing such as etching of a metal vapor deposition film, for example, A technique for printing and forming an electrode pattern on a substrate using an intaglio offset printing technique has been proposed (see, for example, Patent Document 1 and Patent Document 2).

  When the electrode pattern of the liquid crystal display or the like is formed on the substrate, an electrode width as fine as about 10 μm may be required, for example. Furthermore, a plurality of electrode patterns may be formed on the substrate in a superimposed manner. In this case, the electrode pattern is overprinted by replacing the plate, but the electrode pattern may be destroyed if the printing position is shifted. Therefore, although the required accuracy differs somewhat depending on the object, it may be necessary to suppress the overlay deviation to several μm in a fine electrode pattern in which the electrode width is about 10 μm.

  For this reason, printing of electrode patterns on the substrate requires extremely high printing accuracy compared to conventional general offset printing that prints characters and images on paper or the like. As an offset printing apparatus for printing, it is advantageous to use a flat plate printing apparatus of a type that uses a flat plate similar to a printing target as a plate.

  FIG. 8 shows a conventionally proposed offset printing apparatus using a flat plate. A guide rail 2 is provided on a base 1 and is driven by a servo motor 4 in parallel with the guide rail 2. A moving table 7 provided with a ball screw mechanism 3 so that a flat plate (master plate) 5 and a printing object (work plate) 6 can be fixed at a fixed interval is slidably attached to the guide rail 2. At the same time, the ball screw mechanism 3 can reciprocate.

  Furthermore, a blanket roll 9 extending in a direction orthogonal to the linear guide rail 2 and a servo motor 10 for driving the roll connected to one end of the blanket roll 9 in the axial direction are provided at a required portion of the base 1. As a configuration in which the transfer device 8 is provided, the blanket roll 9 is rotated at a required speed by the operation of the servo motor 10 in the transfer device 8, the peripheral speed (circumferential movement amount) of the rotating blanket roll 9, and the plate 5 and when the plate 5 and the printing object 6 on the moving table 7 are passed under the rotating blanket roll 9 while synchronizing the moving speed (movement amount) of the moving table 7 holding the printing object 6 and the moving table 7. The blanket roll 9 is sequentially brought into contact with the surface of the plate 5 and the printing object 6 at a required contact pressure (printing pressure), so that Transfer to emissions socket roll 9 and (acceptance), and to perform the re-transferred (printed) from the blanket roll 9 to the print object 6 are also available implement offset printing (e.g., see Patent Document 3).

  The blanket roll 9 is usually formed with an elastic material having a required elasticity on the surface portion of the peripheral wall, such as rubber, so that the blanket roll 9 can be provided with respect to the surface of the plate 5 or the printing object 6. When contact is made by pressing with a contact pressure, the surface portion of the peripheral wall of the contact portion bends along the surface of the plate 5 or the print target 6 so that the plate 5 or the print target 6 can be in close contact. is there.

  The peripheral speed of the rotating blanket roll 9 is calculated as the product of the angular speed and the rotational radius of the peripheral position. In order to obtain the angular speed of the blanket roll 9, the rotational angle of the blanket roll 9 is detected. Is needed.

  Therefore, conventionally, the rotation angle of the blanket roll 9 is detected based on a detection signal of the rotation amount of the servo motor 10 by an encoder (not shown) attached (built in) to the servo motor 10 that drives the blanket roll 9. Therefore, it is widely and generally performed to derive the peripheral speed of the blanket roll 9.

  Further, in a printing apparatus using a blanket roll, when the blanket roll is driven by a motor via a reduction gear (reduction gear), an encoder (rotary encoder) is attached to the driving motor. (For example, refer to Patent Document 4) When the rotation angle of the blanket roll is detected based on a detection signal of the rotation amount of the motor by the encoder, the reduction ratio of the reduction gear provided between the motor and the blanket roll Depending on the resolution, the resolution is improved.

  The rotational radius of the peripheral position of the blanket roll 9 in contact with the plate 5 or the printing object 6 is determined by the radial size of the blanket roll 9 and the contact pressure required for the blanket roll 9 to be applied to the plate 5 or the printing object 6. The amount of bending that will occur on the peripheral wall of the blanket roll 9 when it is brought into contact with the surface of the blanket roll 9 is calculated using the dimensions obtained in advance from the characteristics of the elastic material on the surface of the peripheral wall of the blanket roll 9. It is generally done.

Japanese Patent No. 2797567 Japanese Patent No. 3904433 JP 2000-272079 A JP 2006-243181 A

  However, in order to achieve very high printing accuracy required when printing a fine print pattern such as the electrode pattern described above by offset printing, a print pattern transferred from a plate to a blanket roll, and It is necessary to further improve the reproducibility of both printing patterns to be retransferred from the blanket roll to the printing target. For this purpose, the amount of circumferential movement of the plate or the part in contact with the printing target on the peripheral wall of the rotating blanket roll It is necessary to precisely synchronize the (circumferential speed) and the amount of movement of the plate or printing target that contacts the blanket roll.

  However, the detection of the rotation angle of the blanket roll based on the detection signal of the encoder (not shown) attached to the servo motor 10 for driving the blanket roll 9 shown in Patent Document 3 above, or the blanket roll shown in Patent Document 4 In the detection of the rotation angle of the blanket roll based on the detection signal of the encoder attached to the motor for driving the motor via the speed reducer, there is a concern that the detection accuracy may be insufficient.

  That is, when the rotation angle of the blanket roll is detected based on the detection signal of the encoder built in the servo motor that drives the blanket roll or the detection signal of the encoder attached to the motor connected to the blanket roll via a speed reducer The detection result includes an error due to torsional deformation of mechanical parts in the servo motor and the speed reducer, and an error due to gear backlash in the power transmission mechanism using the gear.

  For this reason, when printing with very high accuracy that is required to suppress the positional deviation of the printing position to several μm, as described above included in the detection result of the rotation angle of the blanket roll. The effects of errors caused by torsional deformation of mechanical parts and gear backlash cannot be ignored.

  However, even if there are errors due to torsional deformation of the machine parts and gear backlash as described above, it is possible to detect the blanket roll rotation angle to the extent required for conventional general offset printing. Since the accuracy was sufficient, in order to detect more accurately the rotation angle of the blanket roll driven by the motor, the idea of separately providing a new angle measuring device other than the encoder attached to the motor has been proposed. That is not the case.

  The blanket roll rotation radius required to calculate the amount of circumferential movement of the blanket roll is determined by the amount of eccentricity of the blanket roll due to manufacturing accuracy and the surface of the peripheral wall of the blanket roll. Change in the amount of deflection of the surface of the peripheral wall when the blanket roll is brought into contact with the plate or the printing object at a required contact pressure, and the thickness dimension of the plate or the printing object. From the center of rotation of the blanket roll due to various factors such as fluctuations in the plate height and surface height of the printing object due to fluctuations (non-uniformity) of the printing and the surface of the table itself holding the printing object and printing plate In fact, the apparent radius of the peripheral wall of the blanket roll up to the portion that contacts the printing plate or the printing object changes.

  However, with respect to the blanket roll, means for accurately and in real time measuring the apparent radius from the center of rotation to the portion of the peripheral wall of the blanket roll that is actually in contact with the plate or printing object has been proposed. The fact is that there is no.

  Therefore, in the past, it has been difficult to achieve precise synchronization between the circumferential movement amount (circumferential speed) of the blanket roll and the movement amount of the plate or the printing object. For this reason, the positional deviation of the printing position is several μm. There is a problem that it is difficult to perform very high-precision printing that is required to be suppressed.

  Therefore, the present invention can measure the rotation angle of the blanket roll with higher accuracy and apparently extends from the rotation center of the blanket roll to the portion of the peripheral wall of the blanket roll that comes into contact with the plate or the printing object. The radius can be measured accurately and in real time, so that the circumferential movement of the blanket roll and the movement of the plate or printing object can be precisely synchronized, and the number of misalignment of the printing position can be achieved. It is an object of the present invention to provide an offset printing method and apparatus capable of performing printing with very high accuracy that is required to be suppressed to μm.

  In order to solve the above-mentioned problems, the present invention corresponds to claim 1 and travels on a guide rail on a gantry in a state where a blanket roll that is moved up and down by a lift drive mechanism is rotated by a drive motor for rotation. The plate held on the plate table is brought into contact from above, and then the blanket roll is brought into contact with the printing object held on the printing object table running on the guide rail from above, so that the plate In the offset printing method that allows transfer from the blanket roll to the blanket roll and retransfer from the blanket roll to the printing target, the plate on the plate table and the printing target on the printing target table enter the position directly below the blanket roll. Before the printing, the height position of the plate on the plate table or the surface of the printing target on the printing target table on the gantry is previously determined. Then, when the blanket roll is brought into contact with the plate on the plate table or the printing target on the printing target table, the plate on the plate table is moved from the height position on the frame at the rotation center of the blanket roll. And the plate of the blanket roll from the center of rotation of the blanket roll by pulling the height position on the pedestal that is measured in advance at the portion of the surface to be printed on the printing target table that is in contact with the blanket roll. Or the apparent radius of the blanket roll up to the portion that is in contact with the object to be printed, and the amount of circumferential movement of the blanket roll derived from the product of the obtained apparent radius of the blanket roll and the angular velocity of the rotating blanket roll And the amount of movement of the plate due to the travel of the plate table, and the shift of the print target accompanying the travel of the print target table. An offset printing method and the amount to be synchronized respectively.

  Further, in the above configuration, the angular velocity of the rotating blanket roll is detected by an encoder directly connected to the end surface of the rotating shaft opposite to the rotating shaft connected to the rotation driving motor among the rotating shafts at both ends of the blanket roll. It is determined based on the rotation angle of the blanket roll.

  Further, according to claim 3, a plate table and a printing target table that run on the guide rail on the gantry, the plate held on the plate table, and the printing target held on the printing target table, The blanket roll that is moved up and down by the lift drive mechanism is sequentially contacted from above in the state of being rotated by the drive motor for rotation, so that the transfer from the plate to the blanket roll and the retransfer from the blanket roll to the printing object are performed In the offset printing apparatus, a distance sensor for measuring a distance from the plate on the plate table and the printing target on the printing target table is provided at a position upstream of the blanket roll in the printing table traveling direction. A height sensor for detecting the height position of the blanket roll on the gantry at the rotation center; An encoder for detecting the rotation angle of the rotating blanket roll, and based on the signals input from the distance sensor and the height sensor, the plate on the plate table and the surface of the printing target on the printing target table The function of measuring and storing the height position on the gantry of the portion located directly below the height sensor, and when the portion advances directly below the blanket roll and contacts the blanket roll, The blanket is obtained by subtracting the pre-measured height position on the gantry from the height position on the gantry at the center of rotation from the plate on the plate table or the surface to be printed on the printing target table. A function for obtaining an apparent radius from the center of rotation of the roll to a portion of the blanket roll that is in contact with the plate or the printing object; A function of obtaining a circumferential movement amount of the blanket roll by a product of an apparent radius of the blanket roll and an angular velocity of the rotating blanket roll obtained based on a signal input from the encoder, and the obtained blanket roll An offset having a configuration including a controller having a function of synchronizing the amount of circumferential movement of the plate, the amount of movement of the plate due to traveling of the plate table, and the amount of movement of the printing target accompanying traveling of the printing target table. Let it be a printing device.

  Further, in the above configuration, an encoder for detecting the rotation angle of the rotating blanket roll is provided on the end surface of the rotation shaft opposite to the rotation shaft connected to the rotation drive motor among the rotation shafts at both ends of the blanket roll. The structure is such that it is directly connected.

According to the present invention, the following excellent effects are exhibited.
(1) A blanket roll that is moved up and down by a lift drive mechanism is rotated by a drive motor for rotation, and is brought into contact with a plate held on a plate table that runs on a guide rail on a gantry from above, and then The blanket roll is brought into contact with the printing target held on the printing target table running on the guide rail from above, so that the transfer from the plate to the blanket roll and the retransfer from the blanket roll to the printing target are performed. In the offset printing method, the printing on the plate table and the printing target table is performed before the printing plate on the printing table and the printing target on the printing target table enter a position directly below the blanket roll. The height position of the target surface on the gantry is measured in advance, and then the plate on the plate table and the print target table are measured. When the blanket roll is brought into contact with the printing object on the printing plate, the blanket roll on the surface of the printing plate on the printing plate or the printing object table from the height position on the gantry at the rotation center of the blanket roll. By pulling the pre-measured height position of the part in contact with the base, the apparent position from the center of rotation of the blanket roll to the part in contact with the plate or printing object of the blanket roll A radius, a circumferential movement amount of the blanket roll guided by a product of the obtained apparent radius of the blanket roll and an angular velocity of the rotating blanket roll, a movement amount of the plate by running the plate table, and , Offset printing that synchronizes the amount of movement of the print target as the print target table travels Since there is an eccentricity in the blanket roll, there is waviness on the upper surface of the table due to the design accuracy of the plate table or printing target table, the thickness dimension of the plate or printing target. If the height position of the plate held on the plate table or the printing target table or the surface of the printing target fluctuates due to a cause such as non-constant, the printing work is continued and the peripheral wall of the blanket roll is continued. When a change occurs in the elastic performance of the elastic material constituting the surface portion, and the peripheral wall of the blanket roll is brought into contact with the plate on the plate table or the printing target on the printing target table with a required contact pressure. Even if the amount of deformation of the plate changes, from the rotation center of the blanket roll, on the plate table on the peripheral wall of the blanket roll It is possible to detect the apparent radius to the part that is actually in contact with the printing target on the printing plate or the printing target table. Therefore, the amount of circumferential movement of the blanket roll is synchronized by synchronizing the amount of circumferential movement of the blanket roll determined by the product of the detected apparent radius and the blanket roll angular velocity, and the amount of movement of the plate or printing object. It is possible to precisely synchronize the movement amount of the plate and the printing object.
(2) A blanket in which the angular velocity of the rotating blanket roll is detected by an encoder directly connected to the end face of the rotating shaft opposite to the rotating shaft connected to the rotation driving motor among the rotating shafts at both ends of the blanket roll. By determining based on the rotation angle of the roll, the rotation angle of the blanket roll can be accurately measured in a state that does not include errors due to torsional deformation of machine parts and errors due to gear backlash. Therefore, the angular velocity of the rotating blanket roll can be detected with high accuracy based on the signal of the encoder.
(3) According to the above (1) and (2), the apparent radius from the center of rotation of the blanket roll to the portion of the peripheral wall of the blanket roll that contacts the plate on the plate table or the printing target on the printing target table; By synchronizing the blanket roll circumferential movement obtained by the product of the blanket roll angular velocity and the movement of the plate or printing object, the circumferential movement of the blanket roll and the movement of the plate or printing object are more precise. Can be synchronized.

It is a schematic side view which shows one Embodiment of the offset printing method and apparatus of this invention. FIG. 2 is a partially cut side view showing an enlarged transfer mechanism portion in the offset printing apparatus of FIG. 1. It is an AA direction arrow line view of FIG. It is a BB direction arrow line view of FIG. It is a schematic diagram which shows the control structure of the controller with which the offset printing apparatus of FIG. 1 is equipped. FIG. 2 shows a processing procedure by a controller when performing offset printing by the offset printing apparatus of FIG. 1. (A) shows a state in which a plate held on the plate table has reached a position directly below the laser sensor by moving the plate table. (B) is a schematic diagram showing the state in which the plate held on the plate table has reached a position directly below the blanket roll. It is a figure corresponding to FIG. 2 which shows the other form of implementation of this invention. It is a perspective view which shows the outline | summary of the offset printing apparatus using the flat plate conventionally proposed.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIGS. 1 to 6 (a) and 6 (b) show an embodiment of the offset printing method and apparatus of the present invention in which the blanket roll is controlled to have a constant height when it is brought into contact with a plate or a printing object. The following shows an application example in the case of:

  That is, FIGS. 1 to 4 show the offset printing apparatus of the present invention used in the offset printing method of the present invention, and a guide rail 12 extending in one direction (X-axis direction) on the upper side of the horizontal base 11, for example, A set of two guide rails 12 is provided, and a printing table 14 on which a plate 13 such as an intaglio is attached and held on the upper surface and a printing object 15 such as a substrate is attached and held on the upper surface. The target table 16 is slidably attached via individual guide blocks 12a in a state where the target table 16 is arranged in order from one end side (left side in FIG. 1) in the longitudinal direction of the guide rail 12.

  Further, the plate table 14 and the printing target table 16 are allowed to move (run) independently along the guide rail 12 by an individual table driving device 17 such as a linear motor. A linear scale 18 parallel to the guide rail 12 is provided on the gantry 1, and the position along the longitudinal direction of the guide rail 12 of the plate table 14 and the printing target table 16 by the linear scale 18, that is, X An absolute position in the X-axis direction with reference to a required point in the axial direction can be detected together.

  At a position corresponding to the longitudinal direction intermediate portion of the guide rail 12 on the gantry 11, it is arranged above the guide rail 12 so as to extend in a direction perpendicular to the longitudinal direction of the guide rail 12 (Y-axis direction). A blanket roll 20, a roll support frame 22 that rotatably holds the rotation shafts 21 a and 21 b at both left and right ends of the blanket roll 20, and one rotation shaft 21 a of the blanket roll 20 for rotationally driving the blanket roll 20. A rotation drive motor 23 connected to the blanket roll 20, an encoder 24 directly connected to the other rotary shaft 21b of the blanket roll 20 for detecting the rotation angle of the blanket roll 20, and the blanket roll 20 integrally with the roll support frame 22. Elevating drive mechanism 25 for elevating and lowering drive, and elevating drive mechanism It is lowered by 5 providing a transfer mechanism 19 which includes a height sensor 26 for detecting the height position of the blanket roll 20.

  Further, in the roll support frame 22, the transfer from the plate 13 held on the plate table 14 by the transfer mechanism unit 19 to the blanket roll 20 (reception), and the blanket roll 20 is held on the printing target table 16. Further, on the upstream side of the travel direction of each of the tables 14 and 16 (represented by arrows a in the figure, hereinafter simply referred to as the table travel direction during transfer) when retransfer (printing) to the printing object 15 is performed. As a distance sensor for measuring the distance to the surface of the plate 13 held on the plate table 14 passing below and the printing target 15 held on the printing target table 16 at a required portion on the side of the frame facing The laser sensor 27 is provided.

  Furthermore, on the basis of signals inputted from the linear scale 18, the encoder 24, and the laser sensor 27, the individual driving devices 17 for the plate table 14 and the printing target table 16, and the blanket roll 20 are rotated. A controller 28 for giving a command to the drive motor 23 is provided to constitute the offset printing apparatus of the present invention.

  More specifically, as shown in FIGS. 2 to 4, the transfer mechanism 19 is required in the longitudinal direction (X-axis direction) of the guide rail 12 on both the left and right outer sides of the middle portion in the longitudinal direction of the guide rail 12. Two columns 30 having a required height dimension provided at intervals, and the tops of the columns 30 are integrally formed so as to cross over the required dimension of the intermediate portion in the longitudinal direction of the guide rail 12. A gate-shaped frame 29 including a beam member 31 to be connected is provided.

  Furthermore, the roll support frame 22 is configured such that a pair of left and right bearing housings 32a and 32b are integrally connected by a connecting member 33 extending in the left and right direction, and the left and right bearing housings 32a and 32b are connected to the blanket roll 20. The rotary shafts 21a and 21b at both ends of the frame 29 are rotatably held via bearings 34, and the left and right bearing housings 32a and 32b are respectively positioned at the left and right outer positions of the guide rail 12 in the frame 29. It is arranged between two columns 30 arranged along the axial direction, and is attached to each column 30 via a linear guide 35 in the vertical direction so as to be movable in the vertical direction.

  Furthermore, the roll support frame 22 is moved to a position directly above the left and right bearing housings 31a and 31b of the roll support frame 22 in the beam member 31 of the frame 29 through the raising and lowering drive of the bearing housings 31a and 31b. As a lifting drive mechanism 25 for raising and lowering the blanket roll 20 integrally, for example, a ball screw mechanism 25 having the following configuration (for the sake of convenience, the same reference numeral as that of the lifting drive mechanism 25 is provided) is provided. is there.

  The specific configuration of each of the ball screw mechanisms 25 is such that the upper end portion of the screw shaft 36 extending in the vertical direction at a position directly above the left and right bearing housings 32a and 32b of the roll support frame 22 in the beam member 31. The offset portion is rotatably attached via a bearing 37. Each bearing 37 can be supported by receiving a thrust load acting on each screw shaft 36 from a roll support frame 22 to which each nut member 38 screwed to the lower portion of each screw shaft 36 is attached as will be described later. It shall be like that.

  A gear box 40 connected to an elevating drive motor 39 such as a servo motor is disposed at a position above the bearings 37 above the beam member 31, and a support member 41 is placed on the beam member 31. A projecting end portion projecting upward from each bearing 37 of each screw shaft 36 is connected to the output side of each gear box 40.

  Further, nut members 38 that are individually screwed into the lower portions of the respective screw shafts 36 are attached to the upper side of the respective bearing housings 32a and 32b of the roll support frame 22 via the required attachment members 42, so that each of the above-mentioned lifting drive units A ball screw mechanism 25 including a motor 39, each screw shaft 36 that is rotationally driven through the gear box 40 by the operation of each lifting drive motor 39, and each nut member 38 is configured. Thus, in each ball screw mechanism 25, each screw shaft 36 is rotationally driven via each gear box 40 by the operation of each lifting drive motor 39, so that each nut member 38 is integrated with each other. The roll support frame 22 holding the blanket roll 20 can be moved up and down.

  In addition, the raising / lowering range of the blanket roll 20 via the roll support frame 22 by each of the ball screw mechanisms 25 is such that the lower end portion of the outer peripheral surface of the blanket roll 20 runs along the guide rail 12 on the gantry 11. The outer peripheral surface of the blanket roll 20 from the retreat height position where the plate 13 held on the plate table 14 to be held and the surface of the printing target 15 held on the printing target table 16 are separated from the surface by a required dimension. The lower end of the plate is in a range up to a height position slightly below the position at which the plate 13 held on the plate table 14 and the surface of the print target 15 held on the print target table 16 are in contact with each other. It is assumed that it is set to.

  Further, a height sensor 26 for measuring the height of the blanket roll 20 is, for example, an encoder 26 individually attached to each lifting drive motor 39 (for convenience, the same reference numerals as those of the height sensor 26 are attached. Is). Thereby, the rotation amount of each screw shaft 36 via each gear box 40 can be calculated based on the rotation amount signal of each rotation drive motor 23 detected by each encoder 26, and each screw shaft can be calculated. According to the amount of rotation of 36, the position along the longitudinal direction of screw shaft 36 of each nut member 38 screwed to each screw shaft 36 can be detected. At this time, each screw shaft 36 is supported in a state where the relative position to the beam member 31 of the frame 29 is fixed. Therefore, each nut member 38 along the longitudinal direction of each screw shaft 36. Detecting the position of each of the nut members 38 relative to a required position of the frame 29 installed on the frame 11, for example, the position of the beam member 31 of the frame 29 on the frame 11. With reference to the height position b, the vertical distance c from the beam member 31 (height position b) to each nut member 38 can be detected. Further, each nut member 38 is attached to the roll support frame 22 via an attachment member 42, and the rotation shafts 21 a and 21 b of the blanket roll 20 held by the roll support frame 22. Since the relative position is fixed, the vertical distance d from each nut member 38 to the center of rotation of the blanket roll 20 is a known fixed value.

  Therefore, based on the signals input from the encoders 26 of the elevating drive motors 39 by the controller 28, as described above, from the height position b of the beam member 31 of the frame 29, the balls By pulling the distance c of each screw mechanism 25 to each nut member 38 and the known distance d from each nut member 38 to the center of rotation of the blanket roll 20, the controller 28 causes the The height e of the center of rotation of the blanket roll 20 can be detected in real time.

  A reduction gear 43 connected to the rotation drive motor 23 is attached to the outside of one bearing housing 32a of the roll support frame 22, and an output shaft (not shown) of the reduction gear 43 is connected to the one bearing housing 32a. One rotating shaft 21a of the held blanket roll 20 is connected.

  Further, the encoder 24 is attached to the outside of the other bearing housing 32b of the roll support frame 22, and an unillustrated input shaft of the encoder 24 is held by the other bearing housing 32b. 20 is directly connected to the end axial position of the other rotating shaft 21b. Accordingly, the blanket roll 20 can be driven to rotate at a required rotational speed via the speed reducer 43 by the operation of the rotation drive motor 23. At this time, the encoder 24 causes the blanket roll 20 to rotate. The rotation angle with respect to a certain position in the circumferential direction can be accurately measured in a state that does not include errors due to torsional deformation of mechanical parts and errors due to gear backlash. Therefore, the angular velocity of the rotating blanket roll 20 can be detected with high accuracy based on the signal from the encoder 24.

  The width side ends of the plate 13 held on the plate table 14 and the printing target 15 held on the printing target table 16 are arranged on the side of the frame facing the upstream side of the table travel direction a during printing of the roll support frame 22. Laser sensors 27 are attached downward at two locations in the width direction, which are directly above the portion near the section. Thereby, the plate table 14 holding the plate 13 traveling along the table travel direction a during printing and the printing target table 16 holding the printing target 15 are supported by the roll support frame 22 by the laser sensors 27. The surface of the plate 13 or the printing target 15 held on the printing plate table 14 or the printing target table 16 located immediately below the laser sensor 27 at the stage immediately before entering immediately below the blanket roll 20 that has been placed. The vertical distance f can be measured. At this time, since the relative positions of the laser sensors 27 attached to the roll support frame 22 and the rotation shafts 21a and 21b of the blanket roll 20 held by the roll support frame 22 are fixed, For example, the vertical deviation (deviation amount) g from the height position of the rotation center of the blanket roll 20 of the position that becomes the reference for distance measurement in each laser sensor 27 such as the lower end position of each laser sensor 27 is , Some known fixed value. The vertical deviation g is assumed to be a positive value when the distance measurement reference position of each laser sensor 27 is lower than the height position of the rotation center of the blanket roll 20.

  Therefore, the controller 28 sets the distance f from each laser sensor 27 to the surface of the plate 13 or the printing object 15 held on the tables 14 and 16 from the distance measurement reference position of each laser sensor 27. When the detection signal is input, the controller 28 adds the deviation g in the vertical direction from the rotation center of the blanket roll 20 of each laser sensor 27 to the distance f as described above. The vertical distance h from the rotation center of the blanket roll 20 to the surface of the plate 13 or the printing object 15 held on the tables 14 and 16 positioned directly below the laser sensors 27 can be detected in real time. It is like that.

  Further, as shown in FIG. 5, the controller 28 is based on individual table position detection signals of the plate table 14 and the printing target table 16 input from the linear scale 18 provided on the gantry 11. A table that gives commands to the individual driving devices 17 of the plate table 14 and the printing target table 16 so that the position, moving direction (traveling direction) and moving speed (traveling speed) of each of the tables 14 and 16 can be controlled. Based on the detection signal of the rotation angle of the blanket roll 20 input from the travel control unit 28a and the encoder 24 directly connected to the other rotary shaft 21b of the blanket roll 20, a command is sent to the drive motor 23 for rotation of the blanket roll 20. And a roll rotation control unit 28 that can control the angular velocity (rotational speed) and the angular attitude of the blanket roll 20. Includes the door, is a structure in which to be controlled synchronously above, the table travel control unit 28a and the roll rotation controller 28b.

  Further, as described above, the controller 28 determines the height of the rotation center of the blanket roll 20 on the gantry 11 that is detected in real time on the basis of the signals input from the encoders 26 of the lifting drive motors 39. It is held by the tables 14 and 16 positioned immediately below the laser sensors 27 from the rotation center of the blanket roll 20 detected in real time based on the information on the position e and the signals input from the laser sensors 27. On the basis of the information on the vertical distance h to the surface of the printing plate 13 and the printing object 15, a function for correcting the synchronous control of the table travel control unit 28 a and the roll rotation control unit 28 b is provided.

  The offset printing apparatus according to the present invention requires one end in the longitudinal direction of the guide rail 12 at a position corresponding to one end in the longitudinal direction of the guide rail 12 on the mount 11 as shown in FIG. A plate table standby area 44 is provided, which allows the plate table 14 to be moved to a standby position and waits, and the plate 13 held on the plate table 14 to be exchanged, and the plate table standby on the gantry 11 is provided. An inking device 45 for inking the plate 13 held on the plate table 14 is provided between the area 44 and the transfer mechanism unit 19, and the guide rail on the mount 11 is further provided. The table to be printed 16 is moved to the other end in the longitudinal direction of the guide rail 12 at a position corresponding to the other end in the longitudinal direction of the guide 12 and waits. In the state, it is assumed that a constitution comprising a printed installation area 46 for performing the removal of printed 15 after printing and mounting of a new printing target 15 relative to the print target table 16.

  Here, the offset printing method of the present invention will be described in detail in accordance with the specific control contents by the controller 28 described above.

  That is, when offset printing is performed using the offset printing apparatus of the present invention having the above-described configuration, the plate 13 held on the plate table 14 in the plate table standby area 44 in advance is stored in the plate table 14. The plate table 14 holding the inked plate 13 is moved up to the retracted height position by the ball screw mechanisms 25 in the transfer mechanism unit 19 so as to be inked by traveling to the inking device 45. The sheet is moved below the blanket roll 20 in a state to a predetermined position upstream of the transfer mechanism 19 in the table running direction a during printing. The print target table 16 holds the print target 15 to be newly printed in the print target installation area 46.

  In this state, the controller 28 causes the transfer mechanism unit 19 to start the rotation of the blanket roll 20 by the rotation drive motor 23 by the function of the roll rotation control unit 28b, and the function of the table running control unit 28a. The plate table 14 holding the inked plate 13 starts to travel in the table travel direction a during printing. At this time, as described above, the offset printing apparatus according to the present invention sets the height of the blanket roll 20 at a predetermined contact height position when the blanket roll 20 is brought into contact with the plate 13 or the printing object 15. Since it is configured to perform constant height control, the design assumes that the blanket roll 20 is disposed at the predetermined contact height position and is brought into contact with the plate 13 on the plate table 14 traveling on the guide rail. The dimension from the rotation center of the rotation shafts 21a, 21b of the blanket roll 20 to the surface height position of the plate 13 held on the plate table 14 is initially set to the apparent radius of the blanket roll 20. The blanket roll 20 is detected on the basis of a signal input from the encoder 24 directly connected to the other rotary shaft of the blanket roll 20. Based on the circumferential movement amount (peripheral speed) of the blanket roll 20 obtained by the product of the speed and the initial setting value of the apparent radius, and a signal input from the linear scale 18 provided on the gantry 11 The detected traveling speed of the plate table 14 is synchronized.

  Thereafter, as schematically shown in FIG. 6 (a), the plate 13 on the plate table 14 that moves in accordance with the movement of the plate table 14 in the table travel direction a during printing is directly below each laser sensor 27. Then, the distance f from each laser sensor 27 to the surface of the plate 13 on the plate table 14 is measured by each laser sensor 27, and when this signal is input to the controller 28, the controller 28 Then, from the distance f and the vertical deviation g of the distance detection reference position of each laser sensor 27 from the rotation center of the blanket roll 20, from the rotation center of the blanket roll 20, directly below each laser sensor 27. A vertical distance h to the surface of the plate 13 on the plate table 14 located at is detected. At the same time, the controller 28 detects the height position e of the rotation center of the blanket roll 20 on the gantry 11 at that time based on the signal input from each encoder 26 of each lifting drive motor 39. From the height position e of the rotation center of the blanket roll 20 on the gantry 11 to the surface of the plate 13 on the plate table 14 positioned just below each laser sensor 27 from the rotation center of the blanket roll 20 By subtracting the directional distance h, the height position j on the gantry 11 of the portion i located directly below each laser sensor 27 is calculated, and the value is detected based on the signal input from the linear guide 35. The plate 13 on the plate table 14 is temporarily stored in association with the information of the portion i located immediately below each laser sensor of the plate 13, and this processing is performed by the plate 13. While passing under the respective laser sensor 27 along with the traveling of the Le 14, so as continuously.

  As will be described later, when the blanket roll 20 is lowered from the retracted position so as to come into contact with the plate 13 held on the plate table 14, the controller 28 is controlled by the encoders 26 of the lifting drive motors 39. Based on the input signal, a change in the height position e of the rotation center of the blanket roll 20 on the gantry 11 is continuously detected, and the rotation center of the blanket roll 20 on the gantry 11 continuously changing is detected. Vertical distance from each laser sensor 27 continuously detected by each laser sensor 27 from a height position e to a portion located directly below each laser sensor 27 of the plate 13 on the traveling plate table 14 By gradually subtracting the value of h, it passes under each laser sensor 27 in the plate 13 that moves as the plate table 14 travels. The height position j on the mount 11 of the portion i to be calculated continuously, it is assumed you have to be temporarily stored.

  As described above, the height position j on the gantry 11 of the portion i passing the position just below the laser sensor 27 of the plate 13 that moves as the plate table 14 travels is calculated and temporarily stored. Thereafter, as shown in FIG. 6B, when the plate 13 held on the plate table 14 reaches below the blanket roll 20 as the plate table 14 travels, By the operation of the drive motor 39, the blanket roll 20 is lowered from the retracted position to a predetermined height position where the blanket roll 20 contacts the plate 13 on the plate table 14 and a predetermined contact pressure acts, and the plate Transfer (acceptance) from the plate 13 on the table 14 to the blanket roll 20 is started. At this time, the controller 28 calculates the traveling speed of the plate table 14 based on a signal input from the encoder 24 directly connected to the other rotating shaft 21b of the blanket roll 20, and the calculated traveling of the plate table 14 is calculated. From the speed, until the portion of the plate 13 held on the plate table 14 located immediately below each laser sensor 27 is positioned directly below the blanket roll 20 and comes into contact with the blanket roll 20 A time lag is obtained, and the value temporarily stored as the height position j on the gantry 11 of the portion located immediately below the laser sensor 27 at the time point that corresponds to the time lag is the blanket roll 20 at the present time. Is called as the value of the height position j on the gantry 11 of the portion located directly below the height position j, The height of the rotation center of the blanket roll 20 on the gantry 11 calculated based on a signal input from the encoder 26 of the lifting drive motor 39 in a state where the height is controlled to be in contact with the plate 13. The difference from the position e is obtained as an apparent radius r from the rotation center of the blanket roll 20 to the position where the plate 13 on the plate table 14 is actually in contact with the position e. The device 28 detects the apparent radius r of the portion actually contacting the plate 13 of the blanket roll 20 obtained as described above and the encoder 24 directly connected to the other rotary shaft 21b of the blanket roll 20. The amount of circumferential movement (circumferential speed) of the blanket roll is obtained as the product of the angular velocities of the blanket roll 20 to be obtained. A command is given to one or both of the rotation drive motor 23 of the blanket roll 20 and the drive device 17 of the plate table 14 so that the movement amount of the plate 13 accompanying the travel of the held plate table 14 is synchronized. It is.

  Therefore, as described above, the undulation of the upper surface of the plate due to the design accuracy of the plate table 14 and the thickness dimension of the plate 13 are not constant, so that the surface of the plate 13 held on the plate table 14 is not constant. When the height position fluctuates, the apparent radius from the center of rotation of the blanket roll 20 that is controlled to be constant to the portion of the blanket roll 20 in contact with the plate 13 on the plate table 14. As the size of r changes and the apparent radius r changes, the amount of circumferential movement (peripheral speed) of the blanket roll 20 varies even under the condition that the angular velocity of the blanket roll 20 is constant. Although there is a change, the blanket roll is moved from the plate 13 in a state in which the changing circumferential movement amount and the movement amount of the plate 13 on the plate table 14 are always precisely synchronized. Transfer to 0 is performed.

  After the transfer from the plate 13 on the plate table 14 to the blanket roll 20 is completed as described above, the blanket roll 20 is once raised to the retracted height position, and then the print target 15 on the print target table 16 is printed. On the other hand, by performing the same processing as the plate 13 on the plate table 14, the blanket roll 20 performs retransfer (printing) on the printing target 15. As a result, the undulation of the upper surface of the table due to the design accuracy of the print target table 16 and the thickness of the print target 15 are not constant, so that the height of the surface of the print target 15 held on the print target table 16 is high. When the height position fluctuates, the apparent height from the rotation center of the blanket roll 20 that is controlled to have a constant height to the portion of the blanket roll 20 that is actually in contact with the printing object 15 on the printing object table 16. The dimension of the upper radius r changes, and with the apparent change of the dimension of the radius r, the circumferential movement amount (circumference) of the blanket roll 20 even under the condition that the angular velocity of the blanket roll 20 is constant. (Speed) changes, but the circumferential movement amount thus changed and the movement amount of the printing object 15 on the printing object table 16 are always precisely synchronized. In, retransfer to the printing target 15 from the blanket roll 20 is carried out.

  Thus, according to the offset printing method and apparatus of the present invention, the encoder 24 directly connected to the other rotating shaft of the blanket roll 20 is used to adjust the rotation angle of the blanket roll 20 to torsional deformation of machine parts and the gears. It is possible to measure with high accuracy in a state in which an error due to backlash is eliminated, and apparently from the center of rotation of the blanket roll 20 to the portion of the blanket roll 20 that is actually in contact with the plate 13 or the printing object 15. Is measured accurately and in real time, and the amount of circumferential movement (circumferential speed) of the blanket roll 20 is synchronized with the amount of movement of the plate 13 and the printing target 15 due to the travel of the plate table 14 and the printing target table 16. By correcting so that the amount of movement of the blanket roll 20 in the circumference and the amount of movement of the plate 13 and the printing object 15 are precise. It is possible to achieve the period. Therefore, it is possible to print a fine print pattern such as an electrode pattern that requires a positional deviation of the print position to be several μm with very high accuracy.

  Next, as another embodiment of the present invention, FIG. 7 shows an application in which the contact pressure is controlled constant between the blanket roll and the plate or printing object when the blanket roll is brought into contact with the plate or printing object. An example is shown as follows.

  That is, the offset printing apparatus according to the present embodiment has the same configuration as that shown in FIGS. 1 to 6 (A) and (B), and each nut member 38 of each ball screw mechanism 25 as the lifting drive mechanism of the blanket roll 20 is Instead of the structure directly connected to the mounting members 42 attached to the upper sides of the bearing housings 32 a and 32 b of the roll support frame 22, the nut members 38 of the ball screw mechanisms 25 are connected to the roll support frames 22. For example, a ring-shaped load cell 47 loosely fitted on the screw shaft 36 is connected to the mounting member 42 attached to the upper side of the bearing housings 32a and 32b as the load cell 47, for example. Accordingly, the roll support frame 22 and the roll support frame 22 are held together with the nut members 38 screwed to the screw shafts 36 by the operation of the lifting drive motors 39 of the ball screw mechanisms 25. The blanket roll 20 is lowered from the retracted height position so as to press against the plate 13 held on the plate table 14 or the printing target 15 held on the printing target table 16 from above with a required contact pressure. In this case, the reaction force of the contact pressure acting on the blanket roll 20 from the plate 13 or the printing object 15 can be detected by the load cells 47.

  Therefore, the blanket roll is controlled by feedback-controlling each elevating drive motor 39 of each ball screw mechanism 25 so that the reaction force of the contact pressure detected by each load cell 47 becomes constant at a predetermined value. The contact pressure when 20 is brought into contact with the plate 13 or the printing object 15 can be controlled to be constant.

  Other configurations are the same as those shown in FIGS. 1 to 6 (A) and 6 (B), and the same components are denoted by the same reference numerals.

  When using the offset printing apparatus according to the present embodiment, the inking device 45 is used to ink the plate 13 previously held on the plate table 14 as in the offset printing apparatus according to the above embodiment. Thereafter, the plate table 14 holding the inked plate 13 and the print target table 16 holding the print target 15 are both kept on the upstream side of the transfer table travel direction a from the transfer mechanism 19. Then, the roll rotation control unit 28b of the controller 28 causes the transfer mechanism unit 19 to start the rotation of the blanket roll 20 at a predetermined rotation speed by the rotation drive motor 23, and the function of the table running control unit 28a The plate table 14 holding the inked plate 13 is started to travel at a predetermined traveling speed in the table traveling direction a during printing.

  Further, as shown in FIG. 6 (a), as the plate table 14 moves, the plate 13 on the plate table 14 reaches directly below each laser sensor 27, and the plate table is moved from each laser sensor 27 to the plate table. When the measurement signal of the distance f to the surface of the plate 13 on the plate 14 is input, the controller 28 on the platform 11 of the portion i located directly below the laser sensors 27 of the plate 13 on the plate table 14. The height position j of the plate 13 on the plate table 14 detected on the basis of the signal input from the linear guide 35 is calculated and the value of the portion i located immediately below each laser sensor is calculated. The process of temporarily storing the information in association with is continuously performed.

  Thereafter, after the above process is started, as shown in FIG. 6B, when the plate 13 held on the plate table 14 reaches below the blanket roll 20 as the plate table 14 travels. The blanket roll 20 is lowered from the retracted position to a height position where the blanket roll 20 comes into contact with the plate 13 on the plate table 14 by the operation of the up / down drive motors 39, and is further detected by the load cells 47. Control of each raising / lowering drive motor 39 of each said ball screw mechanism 25 is started so that the reaction force of the contact pressure when making the blanket roll 20 contact the said board | substrate 13 becomes fixed.

  At this time, when the contact pressure constant control is started, the height position of the blanket roll 20 is the undulation of the upper surface of the table due to the design accuracy of the plate table 14, the thickness dimension of the plate 13 is not constant, etc. Thus, the elastic position of the elastic material forming the surface portion of the peripheral wall of the blanket roll 20 by changing the height position of the surface of the plate 13 held on the plate table 14 or repeating the printing operation. When the change occurs, the height position of the blanket roll 20 is constantly fluctuated in order to keep the contact pressure constant. Even in this case, the controller 28 controls the ball screws. The height position e on the gantry 11 at the center of rotation of the blanket roll 20 can always be detected based on the signals input from the elevating drive motors 39 of the mechanism 25.

  Therefore, also in this embodiment, the position where the height position on the gantry 11 is detected in advance and temporarily stored in the controller 28 when passing the position directly below the laser sensor 27 is the plate. When the controller 28 reaches just below the blanket roll 20 with a required time lag according to the traveling speed of the table 14, the controller 28 calls information on the height position j on the gantry 11 at the location, and the blanket roll 20 By taking the difference from the height position e on the gantry 11 of the rotation center of the plate, the apparent distance from the rotation center of the blanket roll 20 to the portion where the blanket roll 20 is actually in contact with the plate 13 is apparent. The radius r is obtained, and the obtained apparent radius r and the encoder directly connected to the other rotary shaft 21b of the blanket roll 20 are obtained. A circumferential movement amount (peripheral speed) of the blanket roll is obtained as a product of the angular velocity of the blanket roll 20 detected by the plate 24, and this circumferential movement amount and the plate table 14 accompanying the travel of the plate table 14 are obtained. A command is given to one or both of the rotation drive motor 23 of the blanket roll 20 and the drive device 17 of the plate table 14 so that the movement amount of the upper plate is synchronized.

  Therefore, the apparent radius r changes from the center of rotation of the blanket roll 20 that is controlled to have a constant contact pressure to the portion of the blanket roll 20 in contact with the plate 13 on the plate table 14. As the apparent radius r changes, even if the blanket roll 20 has a constant angular velocity, the change in the amount of circumferential movement of the blanket roll 20 changes. The transfer from the plate 13 to the blanket roll 20 is performed in a state in which precise synchronization between the circumferential movement amount to be performed and the movement amount of the plate 13 on the plate table 14 is always achieved.

  After the transfer from the plate 13 on the plate table 14 to the blanket roll 20 is completed as described above, the blanket roll 20 is once raised to the retracted height position, and then the print target 15 on the print target table 16 is printed. On the other hand, while performing the same process as the plate 13 on the plate table 14, the blanket roll 20 performs retransfer (printing) on the printing target 15 under the constant contact pressure control. As a result, the apparent radius r changes from the center of rotation of the blanket roll 20 to the portion of the blanket roll 20 that is actually in contact with the print target 15 on the print target table 16. This change occurs when the circumferential movement amount (peripheral speed) of the blanket roll 20 changes even when the angular velocity of the blanket roll 20 is constant under the condition that the apparent radius r changes. The re-transfer from the blanket roll 20 to the printing object 15 is performed in a state where precise synchronization of the circumferential movement amount to be performed and the movement amount of the printing object 15 on the printing object table 16 is always achieved.

  Therefore, the same effects as those of the above-described embodiment can be obtained also by the offset printing method and apparatus of this embodiment.

  The present invention is not limited only to the above-described embodiment. For example, as a lifting drive mechanism for the blanket roll 20, the blanket roll 20 is integrated with the roll support frame 22 from a predetermined retreat height position. Range up to a height position at which the blanket roll 20 can be brought into contact with the plate 13 on the plate table 14 and the printing target 15 on the printing target table 16 from above with a required contact pressure applied. Any type of lift drive mechanism other than the ball screw mechanism 25 may be employed as long as it can be moved up and down.

  If the height sensor can detect the height position of the blanket roll 20 that is moved up and down integrally with the roll support frame 22 in the gantry 11, the column 30 of the frame 29 of the transfer mechanism unit 19, and each of the roll support frames 22 will be described. A linear scale is provided in the vertical direction between the bearing housings 32 a and 32 b, or the beam members 31 of the frame 29 are positioned above the bearing housings 32 a and 32 b of the roll support frame 22 in the beam members 31 of the frame 29. Any type of height sensor other than the encoder 26 attached to the lifting drive motor 39 may be used, such as a distance meter that measures the distance between the bearing housing 32a and the bearing housing 32b.

  If the distance between the plate 13 on the plate table 14 and the printing target 15 on the printing target table 16 that is installed at a required portion of the roll support frame 22 can be measured, a displacement meter with high resolution, for example, Any type of distance sensor other than the laser sensor 27, such as a capacitance displacement meter, may be used. Further, the distance sensor moves the plate table 14 holding the plate 13 or the printing target table 16 holding the printing target 15 in the vicinity of the upstream side of the printing table traveling direction a with respect to the blanket roll 20 and the blanket. If it can be installed so as not to interfere with the up-and-down movement of the roll 20 and the roll support frame 22, it may be attached to a required fixing portion on the gantry 11. In this case, the blanket roll which raises / lowers the height position on the mount 11 of the upper surface of the printing target 15 held on the plate 13 or the printing target table 16 held on the printing table 14 by the distance sensor. It becomes possible to directly measure without depending on the height position of 20.

  The inking device 45 may be any type of inking device 45 as long as appropriate inking can be performed on the plate 13 held on the plate table 14.

  The offset printing apparatus of the present invention may be applied to perform printing on any print target 15 other than the substrate.

  Of course, various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 11 Base 12 Guide rail 13 Plate 14 Plate table 15 Print target 16 Print target table 20 Blanket roll 21a, 21b Rotating shaft 23 Rotation drive motor 24 Encoder 25 Ball screw mechanism (elevation drive mechanism)
26 Encoder (Height sensor)
27 Laser sensor (distance sensor)
28 Controller r Apparent radius

Claims (4)

  A blanket roll that is moved up and down by a lifting drive mechanism is rotated by a drive motor for rotation, and is brought into contact with a plate held on a plate table that runs on a guide rail on a gantry from above, and then the blanket roll Is brought into contact with the printing object held on the printing object table running on the guide rail from above, so that the transfer from the plate to the blanket roll and the retransfer from the blanket roll to the printing object are performed. In the offset printing method, before the plate on the plate table or the print target on the print target table enters the position directly below the blanket roll, the plate on the plate table or the surface of the print target on the print target table The height position on the gantry is measured in advance, and then the plate on the plate table or the table to be printed When the blanket roll is brought into contact with the printing target, the blanket roll contacts the plate on the plate table or the surface of the printing target table from the height position on the gantry at the rotation center of the blanket roll. The apparent radius from the center of rotation of the blanket roll to the portion of the blanket roll in contact with the plate or the printing object is obtained by subtracting the height position on the gantry that has been measured in advance. A circumferential movement amount of the blanket roll guided by a product of the obtained apparent radius of the blanket roll and an angular velocity of the rotating blanket roll, a movement amount of the plate by running of the plate table, and the printing Off, characterized in that the amount of movement of the print target accompanying the travel of the target table is synchronized with each other Tsu door printing method.   The angular velocity of the rotating blanket roll is detected by an encoder directly connected to the end face of the rotating shaft on the opposite side of the rotating shaft connected to the rotation driving motor among the rotating shafts at both ends of the blanket roll. 2. The offset printing method according to claim 1, wherein the offset printing is performed based on an angle.   A plate table and a printing target table that run on the guide rails on the gantry are provided, and a plate held on the plate table and a blanket roll that is lifted and lowered by a lifting drive mechanism are rotated on the printing target held on the printing table. In the offset printing apparatus in which the transfer from the plate to the blanket roll and the retransfer from the blanket roll to the printing object are performed by sequentially contacting from above while being rotated by the drive motor for the blanket. A distance sensor for measuring the distance between the plate on the plate table and the printing target on the printing target table is provided upstream of the roll in the table running direction during printing, and on the base of rotation of the blanket roll. A height sensor for detecting the height position in the And an encoder for detecting the rotation angle of the screen, and further, the height sensor of the plate on the plate table and the surface of the printing target on the printing target table based on the distance sensor and a signal input from the height sensor. The function of measuring and storing the height position on the gantry of the portion located directly below the base plate, and the point of rotation of the blanket roll when the portion advances directly below the blanket roll and contacts the blanket roll. The center of rotation of the blanket roll is obtained by subtracting the pre-measured height position on the gantry from the height position on the gantry from the plate on the plate table or the surface to be printed on the printing target table. A function of obtaining an apparent radius from the blanket roll to a portion in contact with the plate or the printing target, and the obtained blanket roll A function for obtaining the circumferential movement amount of the blanket roll by the product of the radius on the hook and the angular velocity of the rotating blanket roll obtained based on the signal inputted from the encoder, and the obtained circumferential movement amount of the blanket roll And an offset having a controller having a function of synchronizing the amount of movement of the plate due to travel of the plate table and the amount of movement of the print target accompanying travel of the print target table. Printing device.   The encoder for detecting the rotation angle of the rotating blanket roll is directly connected to the end surface of the rotation shaft opposite to the rotation shaft connected to the rotation drive motor among the rotation shafts at both ends of the blanket roll. The offset printing apparatus according to claim 3.

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