JP6096505B2 - Printing device - Google Patents

Description

  The present invention relates to a printing apparatus capable of automatically correcting a shift between ink transfer positions in a plurality of plate cylinders.

  Conventionally, for example, a printing apparatus disclosed in Patent Document 1 includes a plurality of plate cylinders, a drive motor that is drivingly connected to each plate cylinder, and a sensor that is disposed to face an ink transfer surface of a printing material. The sensor detects two registration marks transferred to the printing material by the upstream plate cylinder and the downstream plate cylinder among the plate cylinders. A control unit is connected to the sensor and the drive motor, and the control unit transfers the transfer position of the downstream plate cylinder with respect to the transfer position of the upstream plate cylinder based on the two registration marks detected by the sensor. A correction angle θ for matching the two is also calculated, and the phase of the downstream plate cylinder is shifted by the correction angle θ to match the transfer positions of the upstream and downstream plate cylinders.

  By the way, in the printing apparatus as described above, when the transfer positions of the plate cylinders are automatically matched, in order to cope with the control delay (dead time), the printing cylinder is subjected to primary advance correction so that the response is accelerated. In addition to the primary advance correction, a plurality of factors such as high-speed conveyance of the printing material and heat shrinkage are combined, so that the downstream printing plate is transferred to the upstream printing cylinder transfer position. The transfer position of the cylinder may cause so-called hunting, in which the transfer position is largely shifted alternately before and after the plate cylinder rotation direction. As a general method for suppressing this hunting amplification, it is known to lower the control gain.

JP-A-10-86343 (paragraphs 0019-0027, FIGS. 1 and 2)

  However, in a printing apparatus such as that disclosed in Patent Document 1, if the control gain is lowered in order to suppress hunting amplification, both plate cylinders may be used when the transfer positions of the upstream and downstream plate cylinders are automatically matched. Therefore, it takes a long time for the transfer position to coincide with each other after the shift of the transfer position is detected by the sensor, and the defect rate of the printing material increases.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a printing apparatus that can achieve both suppression of amplification of hunting and reduction of a defective rate of a printing material.

  In order to achieve the above object, the present invention changes the transfer position of the downstream plate cylinder while suppressing the hunting amplification when the transfer positions of the upstream and downstream plate cylinders are automatically matched. It is characterized by devised to go.

Specifically, a plurality of plate cylinders that transfer ink to a printing material by a rotating operation, and an upstream plate cylinder and a downstream plate cylinder among the plate cylinders 2 are respectively transferred to the printing material. Mark detection means for detecting two registration marks, transfer position changing means for changing the transfer position of ink to the printing material of the downstream plate cylinder relative to the upstream plate cylinder, the mark detection means and the transfer Control means connected to the position change means and operating the transfer position change means, the control means based on the two registration marks detected by the mark detection means, the downstream plate cylinder with respect to the upstream plate cylinder The downstream plate is used as a calculation unit that calculates a displacement amount Y of the transfer position to the printing material every time each plate cylinder makes one rotation, and a proportional component correction P, a differential component correction D, and a Laplace operator s. The transfer position Z of the cylinder is Formula of (1)
Z (s) = (P + D · s) · Y (s) (1)
Based on the above, the following solution was taken for a printing apparatus having a correction unit that operates the transfer position changing means to coincide with the transfer position of the upstream plate cylinder.

That is, in the first aspect of the invention, when the correction unit performs correction, the transfer position Z of the downstream plate cylinder is alternated before and after the plate cylinder rotation direction with respect to the transfer position of the upstream plate cylinder. A waveform calculation unit that calculates a waveform y = f (t) representing a state of shifting, and a determination unit that determines whether hunting has occurred based on the shape of the waveform y = f (t). When the determination unit determines that hunting has not occurred, the correction unit operates the transfer position changing unit to match the transfer position based on the formula (1), while the determination unit If it is determined that hunting has occurred, the change of the transfer position Z of the downstream plate cylinder based on the above equation (1) is stopped, or the transfer position Z of the downstream plate cylinder is The following formula (2)
Z (s) = P · Y (s) (2)
The transfer position changing means is operated so as to be changed based on the above.

In the second invention, in the first invention, the determining unit, after the transfer position Z of the downstream plate cylinder from the time of detecting the mark the two register t ₀ is changed by the mark detection means, The range of the waveform y = f (t) that goes back from the time t ₀ to the past by the time T, where T is the time of control delay required until the two registration marks are detected again by the mark detection means. hunting if there is no extreme value is determined not to be generated, hunting when the extreme value is in the range of the waveform back only past time T from the time t ₀ y = f (t) is generated in the It is characterized by determining that it is.

  In a third invention, in the first or second invention, the correction unit stops the change of the transfer position Z of the downstream plate cylinder according to the determination by the determination unit, or based on the equation (2). Then, while the plate cylinder rotates a predetermined number of times, the change of the transfer position of the downstream plate cylinder is stopped or changed based on the formula (2). It is characterized by.

  According to a fourth invention, in any one of the first to third inventions, a driving motor is drivingly connected to each plate cylinder, the transfer position changing means is connected to the control means, and The drive motor is drivingly connected to the downstream plate cylinder, and the calculation unit matches the transfer position Z of the downstream plate cylinder with the transfer position of the upstream plate cylinder based on the shift amount Y. A correction angle θ of the downstream plate cylinder for calculating the upstream side and the correction unit, when the transfer positions of the upstream and downstream plate cylinders coincide with each other, the drive motor is driven to increase the upstream angle by the correction angle θ. The downstream plate cylinder is configured to change the phase of the downstream plate cylinder with respect to the side plate cylinder.

  According to a fifth invention, in any one of the first to third inventions, a drive motor is drivingly connected to at least one of the plate cylinders, and the transfer position changing means is provided between the plate cylinders. A compensator roller that is capable of changing the distance L between the transfer positions of the upstream plate cylinder and the downstream plate cylinder by moving by itself and contacting one of the surfaces of the printing material. The unit calculates a correction amount S of the transfer position distance L for making the transfer position Z of the downstream plate cylinder coincide with the transfer position of the upstream plate cylinder based on the shift amount Y, and the correction The unit is configured to change the distance L between the transfer positions by the correction amount S by moving the compensator roller when matching the transfer positions of the upstream and downstream plate cylinders. .

  According to a sixth invention, in any one of the first to fifth inventions, the waveform calculation unit is configured to detect the registration mark of the upstream plate cylinder detected by the mark detection unit a plurality of times in succession. The waveform y = f (t) is calculated by setting the position of the register mark on the downstream plate cylinder as y.

  In a seventh invention, in any one of the first to fourth inventions, the waveform calculation unit sets the waveform y = f ( It is configured to calculate t).

  According to an eighth aspect, in the fifth aspect, the waveform calculation unit is configured to calculate the waveform y = f (t), where y is the correction amount S that has been calculated a plurality of times in succession by the calculation unit. It is characterized by being.

  In the first invention, when changing the transfer position of each plate cylinder, when the hunting occurs, the differential component correction of the primary advance correction that greatly contributes to the hunting amplification is not performed, so that the hunting amplification is prevented. be able to. In addition, when hunting has not occurred, the transfer position of each plate cylinder is sequentially changed, and since it is not necessary to lower the control gain, the time required to match the transfer positions of the respective plate cylinders is minimized. The increase in the defective rate of the printing material can be suppressed by shortening the length.

  In the second invention, when changing the transfer position of each plate cylinder, the timing of the hunting amplification caused by the control delay can be determined based on the past data, so the hunting amplification is surely suppressed. can do.

  In the third invention, since the correction of the transfer position of each plate cylinder is stopped without performing the determination by the determination unit at the timing when the hunting is amplified, the time required for the calculation process of the calculation unit and the waveform calculation process of the waveform calculation unit is reduced. It can be omitted, and the control load of the control means can be reduced.

  In the fourth aspect of the invention, since the transfer position of each plate cylinder can be matched by using a drive motor that rotationally drives each plate cylinder, equipment for matching the transfer position of each plate cylinder is added to the equipment. There is no need, and it can be an inexpensive printing device.

  In the fifth invention, it is not necessary to perform complicated control such as changing the phase of the plate cylinder as in the fourth invention in order to make the transfer positions of the respective plate cylinders coincide with each other.

  In the sixth aspect of the invention, the waveform y = f (t) is calculated using the position data of the registration mark X detected by the mark detection means as it is, so that it is possible to reduce the processing load on the waveform calculation unit. .

  In the seventh and eighth inventions, since the waveform y = f (t) is calculated based on the correction angle θ and the correction amount S that have already been calculated by the calculation unit, the waveform calculation unit in the waveform calculation unit further than the fifth invention. The processing load can be reduced.

1 is a schematic configuration diagram of a printing apparatus according to a first embodiment. A waveform representing a state in which the transfer position of the downstream plate cylinder is alternately shifted before and after the plate cylinder rotation direction with respect to the transfer position of the upstream plate cylinder when the transfer positions of the upstream and downstream plate cylinders are matched. It is a graph which shows y = f (t). FIG. 3 is a diagram corresponding to FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiment is merely exemplary in nature.
Embodiment 1 of the Invention
FIG. 1 shows a printing apparatus 1 according to Embodiment 1 of the present invention. The printing apparatus 1 performs gravure printing on a printing material W such as a plastic film, and includes three plate cylinders 2 arranged in parallel. On the outer peripheral surface of each plate cylinder 2, printing patterns, printing characters, etc. A registration mark X for aligning the two is formed.

  A feeding roll 10a for feeding out the printing material W is provided on the upper left side of FIG. 1, and a winding roll 10b for winding up the printing material W is provided on the upper right side of the paper of FIG. And a plurality of guide rolls 10c are provided between the winding rolls 10b.

  Above each plate cylinder 2, a pressure drum 3 for press-bonding the printing material W to the plate cylinder 2 is disposed, and the printing material W is wound around each guide roll 10c and fed. Is transferred between the plate cylinder 2 and the impression cylinder 3, and ink is transferred to the printing material W while the printing material W is moved by the rotation of the plate cylinders 2.

  A drive motor 4 is drivingly connected to each plate cylinder 2, and an encoder 4 a capable of detecting the rotation angle of the plate cylinder 2 is connected to each drive motor 4.

  The drive motor 4 that rotationally drives each plate cylinder 2 constitutes the transfer position changing means of the present invention, and the drive motor that rotationally drives the downstream plate cylinder 2 in the adjacent upstream and downstream plate cylinders 2. No. 4 changes the transfer position Z of the ink onto the printing material W of the downstream plate cylinder 2 with respect to the transfer position of the upstream plate cylinder 2.

  A scanning sensor 5 (mark detecting means) is opposed to the transfer surface of the printing material W between the plate cylinder 2 and the winding roll 10b located on the most downstream side in the feeding direction of the printing material W. The scanning sensor 5 is arranged so that the registration mark X transferred to the printing material W by the plate cylinders 2 can be detected.

  A control device 6 (control means) is connected to each drive motor 4, the encoder 4 a, and the scanning sensor 5, and the control device 6 outputs an operation signal to each drive motor 4. .

The control device 6 controls the printing material W of the downstream plate cylinder 2 with respect to the upstream plate cylinder 2 based on the registration marks X detected by the scanning sensor 5 in the adjacent upstream and downstream plate cylinders 2. A calculating unit 6a for calculating the amount of transfer position deviation Y to the plate cylinder 2 each time the plate cylinder 2 makes one rotation, and the calculation unit 6a determines the transfer position of the upstream plate cylinder 2 based on the amount of deviation Y. On the other hand, correction angles θ ₁ and θ ₂ for making the transfer position Z of the downstream plate cylinder 2 coincide with each other are calculated.

Further, the control device 6 determines that the transfer position Z of the downstream plate cylinder 2 is expressed by the following equation (1) as the proportional component correction P, the differential component correction D, and the Laplace operator s.
Z (s) = (P + D · s) · Y (s) (1)
And a correction portion 6b for driving the drive motor 4 so as to coincide with the transfer position of the upstream plate cylinder 2.

That is, the correction unit 6b drives the drive motor 4 corresponding to the downstream plate cylinder 2 upstream by the correction angles θ ₁ and θ ₂ when matching the transfer positions in the adjacent upstream and downstream plate cylinders 2. The phase of the downstream plate cylinder 2 with respect to the side plate cylinder 2 is changed.

  Further, when the correction unit 6b corrects the control device 6, the transfer position Z of the downstream plate cylinder 2 is alternately shifted before and after the transfer direction of the plate cylinder with respect to the transfer position of the upstream plate cylinder 2. A waveform calculation unit 6c that calculates a waveform y = f (t) (t is an elapsed time) representing a state, and the waveform calculation unit 6c is detected by the scanning sensor 5 a plurality of times in succession. The waveform y = f (t) is calculated with the position of the register mark X of the downstream plate cylinder 2 relative to the register mark X of the upstream plate cylinder 2 as y (see FIG. 2).

In addition, the control device 6 includes a determination unit 6d that determines whether hunting has occurred based on the shape of the waveform y = f (t), and the determination unit 6d After the transfer position Z of the downstream plate cylinder 2 is changed from the time t _{0 when} each of the registration marks X is detected by the scanning sensor 5 in the side and downstream plate cylinders 2, the scanning sensor 5 again performs the above steps. When the control delay time taken until each register mark X is detected is T, when there is no extreme value C in the range of the waveform y = f (t) retroactive from the time t ₀ by the time T. It is determined that hunting has not occurred, and it is determined that hunting has occurred when there is an extreme value C in the range of the waveform y = f (t) retroactive from time t ₀ by time T. It is configured.

When the determination unit 6d determines that the extreme value C is not present, the correction unit 6b is arranged on the downstream side so that the transfer positions of the upstream and downstream plate cylinders 2 coincide with each other based on the formula (1). When the drive motor 4 corresponding to the plate cylinder 2 is driven and the determination unit 6d determines that the extreme value C is present, the transfer position Z of the downstream plate cylinder 2 is expressed by the following equation (2).
Z (s) = P · Y (s) (2)
The drive motor 4 corresponding to the downstream plate cylinder 2 is driven so as to be changed based on the above.

That is, when there is no extreme value C in the range of time t ₀ from the time T by retroactively waveform y = f (t), in the range of just elapsed waveform y = f (t) the time T from the time t ₀ Since there is no extreme value C, even if the control is delayed by the time T, the direction of shifting the transfer position of the downstream plate cylinder 2 does not become the direction of increasing the hunting amplitude. Therefore, no problem arises even when the correction unit 6b performs control to match the transfer positions. However, if there is an extreme value C in the range of the waveform y = f (t) that goes back from the time t ₀ by the time T, the waveform y = f (t) that has passed the time T from the time t _{0 also} has the range C. Since the extreme value C exists, if the control is delayed by the time T, the direction in which the transfer position Z of the downstream plate cylinder 2 is shifted becomes the direction in which the amplitude of hunting is increased. Therefore, the correction unit 6b does not perform the differential component correction of the primary advance correction that greatly contributes to the hunting amplification when the transfer position Z of the downstream plate cylinder 2 is changed so as not to amplify the hunting. Yes.

When the determination unit 6d determines that the extreme value C is present, the correction unit 6b is configured so that the transfer position Z of the downstream plate cylinder 2 is changed based on the equation (2). When the drive motor 4 corresponding to the side plate cylinder 2 is driven, but the determination unit 6d determines that there is an extreme value C, the transfer position Z of the downstream side plate cylinder 2 based on the above equation (1). The change may be stopped.

  Then, when the transfer position Z of the downstream plate cylinder 2 is changed based on the above formula (2) by the determination by the determination unit 6d, the downstream plate is then rotated while each plate cylinder 2 rotates twice. The transfer position Z of the cylinder 2 is changed based on the above formula (2).

  When the transfer position of the downstream plate cylinder 2 is changed based on the above formula (2), the number of rotations of each plate cylinder 2 is not limited to two rotations as described above, but one rotation. That is all you need.

  Further, the change of the transfer position Z of the downstream plate cylinder 2 based on the above equation (1) may be stopped while each plate cylinder 2 rotates twice.

  As described above, according to the first embodiment of the present invention, when the transfer position of each plate cylinder 2 is changed, the differential component correction of the primary advance correction that greatly contributes to the amplification of hunting is not performed when hunting occurs. Therefore, amplification of hunting can be prevented. If hunting has not occurred, the transfer positions of the plate cylinders 2 are sequentially changed, and it is not necessary to lower the control gain. Therefore, the time required for matching the transfer positions of the plate cylinders 2 Can be made as short as possible to suppress an increase in the defect rate of the printing material W.

  Further, when changing the transfer position of each plate cylinder 2, the timing of hunting amplification due to control delay can be determined based on past data, so that hunting can be reliably suppressed.

  In addition, when the change of the transfer position of the downstream plate cylinder 2 is stopped by the determination by the determination unit 6d, the transfer position of the downstream plate cylinder 2 is changed while the plate cylinder 2 rotates twice thereafter. Since the stop is performed, the correction of the transfer position of each plate cylinder 2 can be stopped without performing the determination by the determination unit 6d at the timing when the hunting is amplified, and the calculation processing of the calculation unit 6a and the waveform calculation of the waveform calculation unit 6c are performed. The control load of the control device 6 can be reduced by omitting processing time.

  Furthermore, since the transfer position of each plate cylinder 2 can be matched by using a drive motor 4 that rotationally drives each plate cylinder 2, a device for matching the transfer position of each plate cylinder 2 is added to the equipment. There is no need, and the printing apparatus 1 can be inexpensive.

  In addition, since the waveform y = f (t) is calculated by using the position data of the registration mark X detected by the scanning sensor 5 as it is, it is possible to reduce the processing load on the waveform calculation unit 6c.

According to the first embodiment of the present invention, the registration mark of the downstream plate cylinder 2 with respect to the registration mark X of the upstream plate cylinder 2 detected by the scanning sensor 5 a plurality of times in the immediate vicinity is detected by the waveform sensor 6c. While the position of the X and calculates the waveform y = f (t) as y, the present invention is not limited thereto, a plurality of times the calculated corrected angle theta ₁ consecutive most recently by the calculation unit _6a, theta ₂ as y The waveform y = f (t) may be calculated. In this way, since the waveform y = f (t) is calculated based on the correction angles θ ₁ and θ ₂ already calculated by the calculation unit 6a, both the upstream and downstream plate cylinders 2 as described above are registered. The calculation processing load in the waveform calculation unit 6c can be further reduced as compared with the calculation by the waveform calculation unit 6c from the mark X.
<< Embodiment 2 of the Invention >>
FIG. 3 shows a printing apparatus 1 according to Embodiment 2 of the present invention. The second embodiment is the same as the first embodiment except that the transfer position of each plate cylinder 2 to the printing material W is not changed by the drive motor 4, and the rest is the same as the first embodiment. Only parts different from the first embodiment will be described.

  The drive motor 4 according to the second embodiment is drivingly connected only to the plate cylinder 2 located on the most upstream side in the feeding direction of the printing material W, and the other two plate cylinders 2 are located on the most upstream side. 2 is connected by a conduction shaft (not shown) and is rotated in synchronization with the rotation of the plate cylinder 2 located on the most upstream side.

Further, a compensator roller 7 that comes into contact with the transfer surface of the printing material W is provided between the plate cylinders 2 in the second embodiment so as to be movable up and down, and the compensator roller 7 constitutes the transfer position changing means of the present invention. The distances L ₁ and L ₂ between the transfer positions of the adjacent upstream and downstream plate cylinders 2 to the printing material W are changed by moving up and down by themselves.

The calculation unit 6a sets the distances L ₁ and L ₂ between the transfer positions for matching the transfer position Z of the downstream plate cylinder 2 with the transfer position of the upstream plate cylinder 2 based on the shift amount Y. The correction amounts S ₁ and S ₂ are calculated.

Further, the waveform calculation unit 6c is configured to calculate the waveform y = f (t), where y is the correction amounts S ₁ and S ₂ that have been calculated a plurality of times in succession by the calculation unit 6a.

When the transfer position of the upstream plate cylinder 2 and that of the downstream plate cylinder 2 coincide with each other, the correction unit 6b moves the compensator roller 7 up and down to the upstream and downstream sides by the correction amounts S ₁ and S _2. The distances L ₁ and L ₂ between the transfer positions of the plate cylinder 2 to the printing material W are changed.

  As described above, according to the second embodiment of the present invention, it is not necessary to perform complicated control such as changing the phase of each plate cylinder 2 as in the first embodiment in order to match the transfer position of each plate cylinder 2. Does not take much time.

Further, since the waveform y = f (t) is calculated based on the correction amounts S ₁ and S ₂ already calculated by the calculation unit 6a, the load of calculation processing in the waveform calculation unit 6c is further reduced than in the first embodiment. be able to.

  In the first and second embodiments of the present invention, in the adjacent upstream and downstream plate cylinders 2, the transfer position of the downstream plate cylinder 2 is made to coincide with the upstream plate cylinder 2. In the upstream and downstream plate cylinders 2 that do not match, the transfer position of the downstream plate cylinder 2 may coincide with the upstream plate cylinder 2.

  In the first and second embodiments of the present invention, the printing apparatus 1 having three plate cylinders 2 arranged side by side has been described. However, the number of the plate cylinders 2 is not limited to three, and any two or more plate cylinders may be arranged. The invention can be applied.

  Furthermore, in Embodiment 2 of the present invention, the drive motor 4 is drive-coupled only to the plate cylinder 2 located on the most upstream side, but the drive motor 4 is drive-coupled to at least one of the plate cylinders 2, The other plate cylinders 2 may be rotated in synchronization with the rotation of the plate cylinder 2 drivingly connected to the drive motor 4.

  In addition, in Embodiments 1 and 2 of the present invention, when the determination unit 6d determines that hunting has occurred and changes the transfer position Z of the downstream plate cylinder 2 based on the above equation (2), Thereafter, while each plate cylinder 2 rotates twice, the transfer position Z of the downstream plate cylinder 2 is changed based on the above formula (2), but the transfer position Z of the downstream plate cylinder 2 is changed. It is not essential to change the transfer position Z of the downstream plate cylinder 2 based on the above formula (2) while each plate cylinder 2 rotates twice after the above is changed based on the above formula (2).

  In the second embodiment of the present invention, the compensator roller 7 moves up and down, but moves in the horizontal direction to change the distance L between the transfer positions of the plate cylinders 2 to the printing material W. There may be.

  Furthermore, in the second embodiment of the present invention, the compensator roller 7 is in contact with the transfer surface of the printing material W, but the compensator roller 7 may be in contact with the non-transfer surface of the printing material W. .

  The present invention is suitable for a printing apparatus capable of automatically correcting a shift between ink transfer positions in a plurality of plate cylinders.

DESCRIPTION OF SYMBOLS 1 Printing apparatus 2 Plate cylinder 4 Drive motor (transfer position change means)
5 Scanning sensor (mark detection means)
6 Control device (control means)
6a calculation unit 6b correction unit 6c waveform calculation unit 6d determination unit 7 compensator roller (transfer position changing means)
X Register mark C extreme value W Material to be printed

Claims (8)

A plurality of plate cylinders for transferring ink to a printing material by rotating operation;
Mark detecting means for detecting two registration marks respectively transferred to the printing material by the upstream plate cylinder and the downstream plate cylinder of the plate cylinders;
Transfer position changing means for changing the transfer position of the ink to the printing material of the downstream plate cylinder with respect to the upstream plate cylinder;
A control unit connected to the mark detection unit and the transfer position changing unit and operating the transfer position changing unit;
The control means determines the amount of shift Y of the transfer position of the downstream plate cylinder to the printing material with respect to the upstream plate cylinder based on the two registration marks detected by the mark detection means. As the calculation unit, the proportional component correction P, the differential component correction D, and the Laplace operator s, the transfer position Z of the downstream plate cylinder is expressed by the following equation (1).
Z (s) = (P + D · s) · Y (s) (1)
A printing apparatus having a correction unit for operating the transfer position changing means to coincide with the transfer position of the upstream plate cylinder,
The control means has a waveform y representing a state in which the transfer position Z of the downstream plate cylinder is alternately shifted before and after the plate cylinder rotation direction with respect to the transfer position of the upstream plate cylinder during correction by the correction unit. = A waveform calculation unit that calculates f (t), and a determination unit that determines whether hunting has occurred based on the shape of the waveform y = f (t),
When the determination unit determines that hunting has not occurred, the correction unit operates the transfer position changing unit to match the transfer position based on the equation (1), while the determination unit When it is determined that hunting has occurred, the change of the transfer position Z of the downstream plate cylinder based on the above formula (1) is stopped, or the transfer position Z of the downstream plate cylinder is Equation (2)
Z (s) = P · Y (s) (2)
A printing apparatus, wherein the transfer position changing means is operated so as to be changed based on The printing apparatus according to claim 1,
After the transfer position Z of the downstream plate cylinder has been changed from the time t _{0 when the} two mark detection means have detected the two register marks, the determination unit again performs the two register marks by the mark detector. Assuming that the time of the control delay until the detection of T is T, hunting has occurred when there is no extreme value in the range of the waveform y = f (t) that goes back from the time t ₀ by the time T. It is determined that hunting has occurred when there is an extreme value in the range of the waveform y = f (t) that goes back from the time t ₀ by the time T to the past. Characteristic printing device. The printing apparatus according to claim 1 or 2,
The correction unit stops the change of the transfer position Z of the downstream plate cylinder according to the determination by the determination unit, or when the correction unit is changed based on the formula (2), then the plate cylinder rotates a predetermined number of times. In the printing apparatus, the change of the transfer position of the downstream plate cylinder is stopped or changed based on the above formula (2). The printing apparatus according to any one of claims 1 to 3,
A drive motor is connected to each plate cylinder,
The transfer position changing means is the drive motor connected to the control means and drivingly coupled to the downstream plate cylinder;
The calculation unit calculates a correction angle θ of the downstream plate cylinder for matching the transfer position Z of the downstream plate cylinder with the transfer position of the upstream plate cylinder based on the shift amount Y,
The correction unit drives the drive motor to change the phase of the downstream plate cylinder relative to the upstream plate cylinder by the correction angle θ when aligning the transfer positions of the upstream and downstream plate cylinders. A printing apparatus characterized by being configured. The printing apparatus according to any one of claims 1 to 3,
A drive motor is drivingly connected to at least one of the plate cylinders,
The transfer position changing means is provided between the plate cylinders, and is in contact with any one surface of the printing material and moves by itself to move between the transfer positions of the upstream plate cylinder and the downstream plate cylinder. A compensator roller capable of changing the distance L,
The calculation unit calculates a correction amount S of the transfer position distance L for making the transfer position Z of the downstream plate cylinder coincide with the transfer position of the upstream plate cylinder based on the deviation amount Y,
The correction unit is configured to change the distance L between the transfer positions by the correction amount S by moving the compensator roller when matching the transfer positions of the upstream and downstream plate cylinders. A printing device. The printing apparatus according to any one of claims 1 to 5,
The waveform calculation unit sets the position of the registration mark on the downstream plate cylinder to the registration mark on the upstream plate cylinder detected by the mark detection unit a plurality of times in succession, and sets the waveform y = f ( A printing device configured to calculate t). The printing apparatus according to any one of claims 1 to 4,
The printing apparatus, wherein the waveform calculation unit is configured to calculate the waveform y = f (t), where y is a correction angle θ that has been calculated a plurality of times in succession by the calculation unit. The printing apparatus according to claim 5, wherein
The printing apparatus, wherein the waveform calculation unit is configured to calculate the waveform y = f (t), where y is the correction amount S that has been calculated a plurality of times in succession by the calculation unit.

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