JPH0224670B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention checks whether the printing plates attached to the plate cylinder of each printing unit of a multicolor printing press are attached to the correct positions and whether the respective color printing plates are in mutual registration. It is related to the device.

Generally, in offset printing, when attaching a printing plate to the plate cylinder of each printing unit, positioning is achieved by fitting a punch hole provided in the printing plate to a pin protruding from the plate cylinder and using a plate vise. The printing plate is attached by fixing one end (the grip), wrapping the printing plate around the plate cylinder in this state, and finally fixing the opposite end (the end of the grip) of the printing plate.

In this case, if the punch holes provided in the printing plate are always formed at a constant position relative to the image, in principle, the relative position of the printing plate of each printing unit can be determined by positioning using the punch holes and pins. However, in reality, it is difficult to always place punch holes in the same position relative to the pattern, and there are also problems with the accuracy of the printing position of the pattern on the printing plate, and the mounting position of the vise on the plate cylinder. Due to various factors such as accuracy and the tightness of the printing plates in a vise on the plate cylinder, the printing plates often do not register with each other when positioned using punch holes and pins.

Therefore, with current multicolor printing machines, adjustment printing is always performed to align the registration when the printing plate is installed, and while checking the registration of the printed matter, any misregistration in the left/right and vertical directions can be corrected using a remote control. In addition, it is essential to correct misregistration that has become distorted by remote control or by stopping the printing press and adjusting the plate vise, and then printing and checking the corrected results on printed matter. .

In this way, with conventional multi-color printing machines, the registration of each printing plate is checked on the printed matter, so it takes a lot of time to adjust the registration, and also requires a lot of paper for adjustment. There are problems such as.

Recently, as a way to solve such problems, as disclosed in Japanese Patent Application Laid-open No. 126537/1983, an automatic drawing machine has been used to print register marks for printing patterns on printing plates and markings for marking the printing plates on each other. After forming registration marks for registration with a scriber needle and forming a pattern on the printing plate based on the registration mark, this printing plate is attached to each plate cylinder in the same manner as before, and the printing machine is operated in this state. Detect the position of the marking mark formed on each printing plate from a preset reference point, calculate the vertical and horizontal deviation of the detected value from the reference value, and calculate only the deviation amount. A device has been proposed that automatically drives the plate cylinders independently to bring each printing plate into register.

Although such a device can solve the above-mentioned problems, its configuration involves a major change in the drive system of the printing press itself, making it quite complex. It is not possible to modify and install the device, so if the user wants the effect provided by the device, he will have to purchase a new printing press with the device, which is very expensive. .

This invention was made in view of the prior art as described above, and its purpose is to eliminate the need to actually print on printing paper in order to align the printing plates of each printing unit with each other. figure,
To provide a printing plate attachment position confirmation device which can easily and quickly confirm the attachment position of a printing plate, has a simple device configuration, and can be easily attached to an existing printing machine.

To summarize the present invention, which has been made to achieve the above object, the printing of each color, in which registration marks for mounting position alignment are formed in the margins on both sides, is attached to the plate cylinders of a plurality of printing units, and the plate cylinders are rotated. The device also includes an imaging device installed in each printing unit to read the registration mark on the printing plate attached to the plate cylinder, and an imaging device installed in each printing unit to read the registration mark on the printing plate attached to the plate cylinder. A timing control means for capturing at a predetermined timing an image signal from the imaging device when photographing the register mark, and a switching circuit for outputting any one image signal from among the image signals captured from the imaging device of each printing unit. , a storage means for storing an image signal output from the switching circuit, a reference mark generation circuit for electrically generating an image signal of a reference mark for comparison with the image signal, and an image signal from the storage means. and a reference mark image signal from the reference mark generation circuit, and a display device for displaying the combined image signal from the mixing circuit.

The present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 1 is an explanatory diagram of the most common sheet-fed four-color printing plate as an offset multicolor printing machine equipped with the device according to the present invention, and FIG. 2 is an explanatory diagram of the confirmation device according to the present invention. , FIG. 3 is a block diagram of each processing circuit, FIG. 4 is a block diagram of the reference mark generation circuit, FIG. 5 is an explanatory diagram of reference mark generation, and FIG. 6 is a diagram of the register mark drawing device. FIG. 7 is an explanatory diagram of a printing plate on which register marks are formed, and FIG. 8 is an explanatory diagram showing the state of reference marks and register marks displayed on a CRT.

In FIG. 1, reference numeral 1 indicates an offset sheet-fed four-color printing machine, in which a large number of sheets of printing paper 9 are stacked on a feeder section 2, and the printing paper 9 is held together by a known structure such as vacuum suction. feeder board 3.
At the top, the position of the printing paper is regulated and the feeding timing is determined, and the printing paper is sent to a printing section consisting of four printing units for each color arranged in series.

In the printing department, each printing unit 10, 20, 30,
40, printing of each color of cyan, magenta, yellow, and black is performed on each plate cylinder 11, 21, 31,
41 to each blanket cylinder 13, 23, 33, 4
The ink transferred to 3 is transferred to each impression cylinder 12, 22, 3.
By being retransferred to the printing paper 9 which is wound around the paper sheets 2 and 42 and conveyed, the printing paper 9 is sequentially overprinted.

The printed printing paper 9' discharged from the final printing unit 40 is delivered to the delivery section 4 via the jaw cylinder 8, where it is delivered to a claw rod mounted on a chain 5' which is passed over the guide wheels 5, 5. The sheets are held in the claws and conveyed onto the paper stacking table 6 by the movement of the chain 5', and then released from the claw rod and stacked on the paper stacking table 6 one after another.

Note that 7 in the figure is a transfer cylinder, which is responsible for transferring printing paper between impression cylinders.

Further, as shown in FIGS. 1 and 2, each printing unit 10, 20, 30, 40 includes a plate cylinder 1.
Registration marks formed on the margins on both sides of the printing plate P which is wound and fixed on the circumferential surface of 1, 21, 31, 41
The TV cameras 14a and 14b, 24a and 24 are equipped with imaging devices, such as CCD imaging elements and imaging tubes, in positions where they can read M ₁ and M ₂ (see FIG. 7).
b, 34a and 34b, 44a and 44b are each plate cylinder 1
1, 21, 31, and 41 at the same position. This imaging device has a registration mark
Since M ₁ and M ₂ are formed in the margins on both sides of the printing plate P, one printing unit has, for example, 14a.
Two units will be installed, such as 14b and 14b.

Furthermore, 51 is a rotary encoder as a pulse generating means for generating pulses according to the operating conditions of the printing press, and is provided to determine the timing of capturing image information photographed by the above-mentioned imaging device. In this embodiment, the rotary encoder 51 is connected to the impression cylinder 12 of the printing unit 10.
However, it is not limited to this position, and may be provided at any other position such as an impression cylinder, plate cylinder, etc., which can generate pulses corresponding to the operating speed of the printing press.

Reference numeral 61 is a reference sensor that emits a signal that serves as a reference timing for capturing image information from an imaging device.
It detects rotation and emits one pulse signal each time. Therefore, in this embodiment the reference sensor 61 is connected to the printing unit 1 as shown in FIG.
It is attached to an impression cylinder 12 having the same circumferential length as the plate cylinder of No. A light emitting/receiving element 63 is provided to detect the reference hole 64, and after the light emitting/receiving element 63 detects the reference hole 64 and emits one pulse, the pressure cylinder rotates once and the pulse is emitted again. The reference hole 64 reaches the installation position of the light emitting/receiving element 63 and a pulse is generated.
It is capable of detecting rotation.

Note that this reference sensor 61 has its mounting position,
The configuration is not limited to the above embodiment, and any structure that can generate a signal capable of detecting one rotation or several rotations of the plate cylinder may be used.

As shown in FIG.
0, 20, 30, 40 imaging devices 14a and 14
b, image signals from 24a and 24b, 34a and 34b, 44a and 44b, rotary encoder 5
The pulse signal from 1 and the plate cylinder one rotation detection signal from the reference sensor 61 are each input to the processing circuit 100, and the image signal from the processing circuit 100 is input to the processing circuit 100.
The image is input to the CRT display devices 15, 25, 35, and 45, and the image is displayed on the CRT screen.

On the other hand, as described above, the printing plates P attached to each plate cylinder of the printing press have register marks M ₁ and M ₂ formed in the margins on both sides thereof.

As shown in FIG. 7, the register marks M ₁ and M ₂ are all in constant positions relative to the register mark M ₃ for printing the pattern on each color printing plate.
In addition, it must not fall off during the pattern formation process (baking, development, burning, etc.) on the printing plate.

In this way, in order to form the register marks M ₁ , M ₂ and register marks M ₃ on the surface of the printing plate P, it is sufficient to use, for example, the automatic register mark drawing apparatus 200 shown in FIG. 6.

This register mark automatic drawing device 200 has a drawing table 207 on which a printing plate P is placed, and an X-axis rail 205 is provided in front and behind the drawing table 207.
A Y-axis rail 204 spans the axis rail 205, a head 203 is attached to the Y-axis rail 204, and the Y-axis is driven by an X-axis drive motor (not shown).
The head 203 is movable on the plane of the drawing table 207 by moving the shaft rail 204 in the X-axis direction and moving the head 203 in the Y-axis direction by a Y-axis drive motor (not shown).

Reference numeral 206 denotes a punch block, which holds a punched hole in a portion corresponding to the grip of the printing plate placed on the drawing table, so that the printing plate P is fixed on the drawing table. Ru. In addition, the head 203
is equipped with a scribing device, for example, and in response to instructions from the arithmetic and control unit 202, register marks M ₁ for printing a desired pattern and register marks M ₂ and M ₃ are placed at predetermined positions relative to the register mark M ₁ .
can be formed automatically.

Such a register mark automatic drawing device 20
Register mark M ₃ and register mark M ₁ , M ₂ at 0
If you form a
The mutual positions among M ₁ , M ₂ and M ₃ can be constant.

Next, the processing circuit 100 will be explained based on FIG.

Imaging device 1 provided in printing unit 10
The output signals of 4a and 14b are sent to the A/D conversion circuit 101.
a and 101b, and further converted into digital signals by compression circuits 102a and 102b.
The signal from the D conversion circuit 101a is transmitted to a CRT (described later).
The signal from the A/D conversion circuit 101b is compressed so that it exists only in the area corresponding to the right half of the screen.

The image signals from the two compression circuits 102a and 102b are combined in an OR circuit 103, and the combined image signal is then input to one terminal of an exclusive OR circuit 104. The exclusive OR circuit 104 is responsible for inverting positive and negative images, and the switch 105 connected to the other terminal
When it is open, a negative image signal is output in response to the input image signal, and when it is closed, a positive image signal is output.

106 is a gate circuit, and the imaging device 14a,
The image signal from 14b is subjected to 1 vertical blanking (1.
B.) It outputs only the period.

The timing at which the gate circuit 106 opens is determined by the following configuration. That is, the pulse signal emitted from the rotary encoder 51 is counted by the counter 107, and since this count corresponds to the rotation angle of the plate cylinder, the image signal capture timing setting switch 109 is used to set the predetermined rotation of the plate cylinder. The angle, that is, the numerical value corresponding to the angle at the time when the register mark is photographed is set, and the comparator 10
8, the count number from the counter 107 and the value of the image signal capture timing setting switch 109 are compared, and when the two match, the comparator 10
8 outputs a signal for capturing one pulse image signal. Note that the counter 107 is the reference sensor 61.
The signal from the plate cylinder is used as a clear signal, so that the counter 107 is cleared by one revolution of the plate cylinder.

If the pulse signal from the comparator 108 is directly input to the 1 vertical blanking signal (1..) generation circuit 113, the output signal from the 1.. generation circuit 113 becomes the gate signal responsible for opening and closing the gate 106. An image signal is output from the gate 106 every time the plate cylinder rotates, and the contents of the storage device 153 are rewritten each time, and the display on the CRT is also changed each time.

In this invention, the output signal from the comparator 108 is not directly input to the generation circuit 113 because the plate cylinder rotates quickly and there is no necessity to refresh the displayed image every time the plate cylinder rotates. A counter 110 and a comparator 11 are used to open the gate 106 once every several revolutions of the plate cylinder.
1 and a sampling interval switch 112.

That is, a desired number of sampling intervals is set by the sampling interval switch 112, and the set number is compared with the number counted by the counter 110 (equal to the number of rotations of the plate cylinder) by the comparator 111, and when they match, the comparator 111 outputs a pulse signal, and by inputting this pulse signal to the 1.. generation circuit 113, the 1.. generation circuit 113 issues a command to open the gate 106 for one vertical blanking period at a desired sampling interval. 106, and an image signal is output.

Note that the counter 110 is cleared by the output signal from the comparator 111.

Although omitted in Fig. 3, the number 10
Circuits completely similar to the circuits existing in the block indicated by 0C are arranged in the blocks indicated by numbers 100M, 100Y, and 100BK corresponding to each printing unit 20, 30, and 40, and
a and 24b, 34a and 34b, and 44a and 44b are connected to A/D conversion circuits of 100M, 100Y, and 100BK, respectively, and the output of the counter 107 is connected to comparators of 100M, 100Y, and 100BK, respectively. .

Here, 100C, 100M, 100Y, 10
The values of each image signal capture timing setting switch 109 present in 0BK are determined as follows.

That is, each printing unit 10, 20, 30, 40
In the image pickup device, the plate cylinders 11, 21, 31, 41
It is installed in a certain positional relationship with respect to the
In addition, in a normal printing press, the phases of the printing plates attached to each plate cylinder are different, so the timing of capturing the image signal from the imaging device, that is, the timing of opening each gate 106, depends on the plate cylinder position unique to the printing machine. It is necessary to make them different according to the phase difference.

On the other hand, as a matter of course, it is necessary to capture image information during the period when the register mark is in the field of view of the imaging device. The count number of the pulse signal from the rotary encoder 51 at a certain moment while the registration mark of the plate is in the field of view of the imaging device is set as the number set in the image signal capture timing setting switch 109 of the printing unit 10, and is set in the image signal capture timing setting switch 109 of the printing unit 10. 20, 30, and 40, the timing setting switch 1 of the printing unit 10 is set by the number of pulses corresponding to each phase difference from the printing unit 10.
By adding or subtracting from the set number of 09 and setting the value, the timing to capture the image signal is determined.

As a result, the capture of image signals from the imaging devices of each printing unit is synchronized, and if the printing plates are registered with each other, the registration marks on the CRT display screen (described later) will completely overlap. There will be.

Such circuits 100Y, 100M, 100
The output image signal of C, 100BK is the switching circuit 160.
The switching circuit 160 selectively outputs one of these image signals.
This switching circuit 160 may be of a type in which an operator manually switches the connection terminal to select the image signal to be output.

The image signal output from the switching circuit 170 is
A counter 172 counts clocks generated from a clock generation circuit 173, and the counted number is sequentially stored in a storage device 171 as an address signal.

Further, the reference mark generation circuit 120 electrically generates a reference mark that is always displayed on the CRT display device.

If I explain this, now the register mark
M ₁ and M ₂ are "+" and "-" respectively, and this image
If the reference marks are to be displayed on the left and right sides of one CRT screen, the reference marks should also be displayed in the same shape and size.

To generate such a reference mark, for example, a circuit as shown in FIG. 4 may be used, and its configuration and operation will be explained with reference to a schematic diagram of a CRT screen shown in FIG. 5.

Incidentally, im in FIG. 5 indicates the number, and jm indicates the number of clocks.

First, in order to generate the vertical line VL that is part of the "+" mark, the horizontal blanking signal (..
The clock signal CK from the synchronization signal generation circuit 121 is counted by the vertical line counter 122, which uses the vertical line counter ₁₂₂ as a clear signal. The count number from the counter 122 and the set value _j2 from the switch 138 are compared, and when the count number matches the set value _j2 , a match signal is output from the comparator 130. By performing this operation for each signal,
It is possible to obtain an image signal that can display a vertical line with a thickness of one clock from the top to the bottom on a CRT screen. If you want to give this vertical line a certain thickness, use the vertical line counter 1.
A plurality of switches may be provided for 22, and a plurality of consecutive clock numbers may be set for each of them.

Since the vertical line obtained in this manner extends over the entire length of the screen in the vertical direction, in this embodiment, unnecessary portions at the top and bottom are electrically masked. That is, the upper limit counter 123 which uses the vertical blanking signal (..) as a clear signal outputs the horizontal blanking signal (.., scanning line) for one vertical blanking period.
The comparator 131 compares the count from the upper limit counter 123 with the switch 1.
The number _i1 of horizontal blanking signals from the top io on the screen to the position where no vertical line is required is compared with the number i1 set to 39, and when the two match, the comparator 131
By outputting a signal that becomes "1" from , it is possible to specify the boundary line i ₁ of the unnecessary portion of the vertical line at the top of the screen. In a similar way, the lower limit counter 12
4. By combining the comparator 132 and the switch 140, it is possible to specify the boundary line _i3 of the part where the vertical line at the bottom of the screen is unnecessary.

The output terminal of the comparator 131 is connected to the J terminal of the JK flip-flop 146, and the output terminal of the comparator 132 is connected to the K terminal of the JK flip-flop 146, respectively. Therefore, the output terminal of the JK flip-flop 146 is connected to the upper (i ₀ - i ₁ ) and lower part of the screen. (i ₃
The masking signal becomes "0" at the center portion (i ₄ ) and "1" at the central portion (i ₁ -i ₃ ). Note that .. is input to the reset terminal of the JK flip-flop 146 and is reset every vertical blanking period. By using the masking signal from the JK flip-flop as a gate signal and inputting the image signal for displaying a vertical line from the comparator 130 to the gate circuit 149, as shown in _{FIG .} A vertical line VL can be displayed only in the range of ~ _i3 .

Next, to display the horizontal line HL at the "+" mark and the "-" mark, the horizontal line counter 125 uses .. as a clear signal to count the number of .. at 1. The count number from 125 is compared with the number _i2 set by the switch 141, and when the two match, the comparator 133 outputs that number.
Outputs a signal to display an image (horizontal line) at HB. This horizontal line has a thickness of 1. If you want to give it a certain thickness, use the horizontal line counter 12.
It is sufficient to provide a plurality of switches for 5 and set the number of consecutive .. to each of them.

Since the horizontal line obtained in this manner spans the entire length of the screen in the horizontal direction, in this embodiment, unnecessary portions on the left, right and center are electrically masked.
That is, the left limit counter 126, center left counter 127, center right counter 128, and right limit counter 129 are cleared by 1.
B. Count the clock signal CK in period,
These counts and switches 142, 143,
Number of clocks set in 144,144
j ₁ , j ₃ , j ₄ , j ₅ and comparators 134 and 13, respectively
5 and 136, and when they match, a matching signal is output from each of the comparators 134, 135, 136, and 137.

The output terminals of comparators 134 and 135 are
The JK flip-flop 147 is connected to the J and K terminals of the JK flip-flop 147.
The output signal changes from "0" to "1" when a match signal is input to the J terminal, and the masking signal changes from "1" to "0" when a match signal is input to the K terminal. can get. Also, comparator 1
The output terminals of 36 and 137 are connected to the J and K terminals of the JK flip-flop 148, respectively, and therefore the output signal of the JK flip-flop 148 changes from "0" to "1" at the moment a match signal is input to the J terminal. However, when a match signal is input to the K terminal, the masking signal returns from "1" to "0" again. Therefore, the image signal displaying the horizontal line from the comparator 133 is sent to the JK flip-flop 1.
By inputting the masking signal from 47 to the gate circuit 150, which uses the masking signal as a gate signal, the gate circuit 150 outputs an image signal in which only the area from clock number j ₁ to j ₃ is not masked, as shown in FIG. On the other hand, by inputting the image signal displaying the horizontal line from the comparator 133 to the gate circuit 151 which uses the masking signal from the JK flip-flop 148 as the gate signal, the gate circuit 151 outputs the image signal from the clock number j ₄ to j ₅ . An image signal that is not masked is output only in this case. In addition, JK flip-flop 147,
.. is input to the reset terminal of 148, and 1.
B. It is reset every time.

Such gate circuits 149, 150, 151
The image signal from is input to the OR circuit 152, and the OR circuit outputs an image signal of the "+" and "-" reference marks as shown in FIG. In addition, the display position of the fiducial mark on the screen of the CRT display device is
When the printing plate is normally attached to the plate cylinder, it is preferable to set the position at which the registration mark appears most frequently on the screen of the CRT display device, and to achieve this, adjust the setting values of each switch as appropriate. Good. The shape and size of the generated fiducial mark can be changed to a predetermined shape by changing the setting values of each switch. Can be matched to shape.

The aforementioned storage device 171 and reference mark generation circuit 120 are each connected to a mixing circuit 180 , and the mixing circuit 180 receives horizontal and vertical blanking signals from the synchronization signal generation circuit 121 and generates registration marks on the printing plate from the storage device 171 . The image signal of the reference mark and the image signal of the reference mark from the reference mark generation circuit 120 are combined.

In this embodiment, a CRT display device 15 for register confirmation is provided for each printing unit, since many current printing presses have a register adjustment operation section for each printing unit. 25, 35,
45, and for this purpose, the composite image signal from the mixing circuit 180 is sent to the video amplification circuit 18.
1 and then input to each CRT display device.
It should be noted that if the printing machine is one in which register adjustment can be performed by central remote control, then the operating section may have only one CRT display device, and of course, in this case, an image amplification circuit is not required.

Next, using the confirmation device as described above, confirmation of the attachment position of each color printing plate attached to the printing machine and correction of the position after confirmation will be explained.

First, as already mentioned, on the offset printing plate, as shown in Figure 6, register mark M ₃ is placed on the printer using the register mark automatic drawing device to regulate the printing position of the image and on the margins on both sides of the printing plate. Register marks M ₁ and M ₂ used to align the printing plates with each other are formed so that there is no deviation in position between the printing plates. (See Figure 7) Patterns of each color are formed on each of these printing plates,
After that, each printing unit 10, 20, 3 of the printing press
It is attached and fixed to the 0.40 plate cylinder using the usual method.

After that, the printing press is idled without passing the printing paper through it, and the register marks M ₁ and M ₂ of each printing plate are photographed by the imaging device attached to each printing unit. Capture image signals from. This image signal includes register marks M ₁ ,
Both of M ₂ have been compressed so that they can be displayed on one screen of a CRT display device, and in this example,
The screen of the CRT display device is divided into left and right halves, and the format is such that register marks _M1 and _M2 can be displayed on each side.

On the other hand, the reference mark generation circuit 1 of the processing circuit 100
An image signal capable of displaying an image of a reference mark having the same shape and size as the display image of the register marks M ₁ and M ₂ on the CRT display device is emitted from 20, and the reference mark and the captured image are displayed on the screen of the CRT display device. The register marks M ₁ and M ₂ taken in from the device are displayed in a composite manner. This state is shown in FIG. In Fig. 8, m ₁ ′ and m ₂ ′ are reference marks;
m ₁ and m ₂ indicate register marks photographed by an imaging device of one printing unit. Since the register marks m ₁ ′ and m ₂ ′ are out of position with respect to the reference marks m ₁ ′ and m ₂ ′, the plate cylinder or printing plate is moved by operating the plate register adjustment device of the printing press. The register marks m ₁ ′, m ₂ ′ are completely overlapped with the reference marks m ₁ ′, m ₂ ′.

Next, the switching circuit 180 switches the image to be displayed on the CRT display device, and displays the register marks m ₁ and m ₂ of the printing plate in another printing unit. The reference marks m ₁ ′ and m ₂ ′ are always displayed.
The two are compared, and if they are misaligned, the printing plate or plate cylinder of the printing unit is corrected so that the two completely overlap as described above.

By performing these operations on the printing plates of all four printing units, you can confirm the mounting position of the printing plates, and also check the reference marks that are always displayed while looking at the CRT display.
By sequentially correcting the images of the register marks of each printing unit on m ₁ ′ and m ₂ ′ so that they completely overlap, it is possible to align the printing plates with each other.

Note that the above confirmation can be made more easily if either the reference mark or the register mark displayed on the CRT display device is displayed in positive/negative inversion.

The above is a description of one embodiment of the present invention, and the present invention is not limited to the above embodiment in any way.

That is, although an offset sheet-fed four-color printing press has been described as an example of a printing machine, other offset multi-color printing machines, such as an offset rotary printing press, may be used.

In addition, the shape of the register mark provided on the printing plate is not limited to "+" and "-", but also "∠" and "〓".
Any mark that can detect the vertical direction, horizontal direction, and twist, such as "〓", may be used.

Furthermore, in this embodiment, the screen of the CRT display device is divided into left and right halves, and both the register marks M ₁ and M ₂ are displayed on one screen, but each is divided into left and right parts.
It may be displayed on a display device. Therefore, in this case, a compression circuit or the like is not required.

This invention is as described in detail above, and when registering printing plates of an offset multicolor printing machine, a reference mark and a register mark are sequentially synthesized and projected on a CRT screen, and these marks are Depending on the overlap, you can easily check the mounting position of the printing plate to be adjusted relative to the reference printing plate, and if the printing plate is not in the correct position, use this CRT.
The register can be easily adjusted by remotely controlling the printing plate to be adjusted so that the register mark overlaps the reference mark while looking at the screen.

Therefore, compared to the conventional method, the time required for registering the printing plate is greatly shortened, and printing paper for registering is also no longer necessary.

Furthermore, the confirmation device according to the present invention can be installed in an existing printing press without changing its basic structure, making it possible to effectively utilize the existing printing press, resulting in extremely practical and excellent effects. It is something that plays.

[Brief explanation of drawings]

The drawings show one embodiment of the invention,
FIG. 1 is an explanatory diagram of an offset sheet-fed four-color printing press equipped with a device according to the present invention;
The figure is an explanatory diagram of the device according to the present invention, and the third
4 is a block diagram of a processing circuit, FIG. 4 is a block diagram of a reference mark generation circuit, FIG. 5 is an explanatory diagram of reference mark generation, and FIG. 6 is an explanatory diagram of a register mark drawing device. , FIG. 7 is an explanatory diagram of a printing plate on which register marks are formed, and FIG. 8 is an explanatory diagram showing the state of reference marks and register marks displayed on a CRT. 11... plate cylinder, 14a, 14b... imaging device,
15...CRT, 51...Rotary encoder,
61...Reference sensor, 100...Processing circuit, _M1 ,
_M2 ...Register mark, _m1 , _m2 ...Register mark displayed on the CRT screen, m1 _' , _m2 '...Reference mark displayed on the CRT screen, P...Printed version.

Claims (1)

[Claims] 1 Attach each color printing plate with registration marks formed in the margins on both sides for mounting position alignment to the plate cylinders of multiple printing units, and check the installation position of each printing plate based on the registration marks while rotating the plate cylinders. In a device that performs printing, an imaging device is provided in each printing unit to read the register mark on the printing plate attached to the plate cylinder, and a timing control is provided in each printing unit to capture image signals from the imaging device at a predetermined timing. means, a switching circuit for outputting any one image signal among the image signals taken in from the imaging device of each printing unit;
a storage means for storing the image signal output from the switching circuit; a reference mark generation circuit for electrically generating an image signal of a reference mark for comparison with the image signal; and an image signal from the storage means. A printing plate attachment position confirmation device for a multicolor printing press, comprising: a mixing circuit that combines the reference mark image signal from the reference mark generation circuit; and a display device that displays the composite image from the mixing circuit. .