JPH0224669B2 - - 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 about the method.

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 of the printing plate (the end of the grip). .

In this case, if the punch holes provided in the printing plate are always formed at a constant position with respect to the pattern, 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. Register marks for registration are formed with a scriber needle, and a pattern is formed on the printing plate based on the registration mark.The 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 method for confirming the mounting position of a printing plate, which can easily and quickly confirm the mounting position of a printing plate, has a simple configuration, and can be easily applied to an existing printing machine.

The present invention, which has been made to achieve the above object, is a method for confirming the mounting position of printing plates in order to align the printing plates mounted on the plate cylinders of each printing unit of a multicolor printing press with each other. Registration marks are formed at predetermined positions on the surface of the printing plate, and registration marks that do not fall off during the printing and development process are provided on the margins on both sides of the printing plate surface, so that the pattern and registration marks after the printing and development process are formed. The printing plates of each color on which the marks have been formed are attached to the plate cylinders of each printing unit, the register marks of the printing plates attached to each printing unit are photographed, and the images of the register marks output from each printing unit are displayed on the CRT display device. The image of the register mark from one randomly selected printing unit and the image of the reference mark are combined and displayed, and the images of the register mark output from each printing unit and displayed on the CRT display device are switched and sequentially displayed. This is a method for confirming the mounting position of a printing plate in a multicolor printing machine, in which the mounting position of the printing plate is confirmed by comparing the image of each register mark with the reference mark and checking the overlapping state of the image of each register mark and the image of the reference mark.

Hereinafter, the present invention will be explained in detail based on embodiments of the drawings.

First, as shown in FIG. 1, register marks are drawn on the photosensitive layer surface of an offset printing plate, for example, a flat printing plate commonly called a PS plate.
The register mark is a register mark M3 for aligning the register with the film original plate when printing a pattern to be formed on the printing plate P, and a register mark _M3 for aligning the register between the printing plates used in the present invention. ₁ , _M2 .

The registration mark _M3 corresponds to the registration mark formed on the film original plate, and is used to determine the position of pasting the film original plate on the surface of the printing plate P, and is suitable for multicolor printing machines. In this case, all the printing plates corresponding to the number of colors are formed in the same positional relationship.

Registration marks M ₁ and M ₂ are used to align the printing plates with each other after they are attached to the plate cylinder of each printing unit of a multicolor printing machine, and are used to correct misalignment in the left-right direction and vertical direction. It must be possible to check for deviations and twists.

Therefore, in this embodiment, a "+"-shaped register mark _M1 and a "-"-shaped register mark _M2 are formed in the margins on both sides of the printing plate.

Register mark M ₁ with the position and shape as above,
According to M ₂ , as is clear from Fig. 2, compared to the reference marks M' ₁ and M' ₂ , there is a positional deviation in the left and right direction as shown in Fig. 2A, and a vertical position deviation as shown in Fig. 2B. All positional deviations, such as directional positional deviations, twists as shown in Figure C, or combinations thereof as shown in Figure D, can be confirmed.

Note that the shapes of the register marks M ₁ and M ₂ are not limited to this example, and may have other shapes, such as "〓".
"∠", "〓" etc. are also acceptable.

Furthermore, the register marks M ₁ and M ₂ must not fall off during printing plate preparation processes such as pattern printing and development, which will be described later. For this reason, it is preferable to make the register mark by, for example, scribing or the like.

The register marks M ₁ and M ₂ as described above must be formed at a constant position with respect to the register mark M ₃ on all printing plates installed on the same printing press.

To form the register marks M ₁ , M ₂ and registration mark M ₃ in such a relationship, an automatic register mark drawing apparatus such as that shown in FIG. 3 may be used, for example. This register mark automatic drawing device 20
0 has a drawing table 207 on which a printing plate P is placed,
An X-axis rail 205 is provided in front and behind the X-axis rail 205, a Y-axis rail 204 spans over this X-axis rail 205, and a head 203 is provided on the Y-axis rail 204.
is attached, and the Y-axis rail 204 is moved in the X-axis direction by an X-axis drive motor (not shown), and the head 203 is moved in the Y-axis direction by a Y-axis drive motor (not shown), so that the head 203
It can move freely on 7 planes. 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. Further, the head 203 is equipped with, for example, a scribing device, in which a registration mark M ₁ for printing a desired pattern according to a command from the arithmetic control unit 202 and a registration mark M placed at a predetermined position with respect to the registration mark M ₁ are provided. ₂ , _M3 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.

Thereafter, each printing plate is closely printed with the image of the film original plate, and is subjected to development, washing, gumming, etc., and each color separation image is formed on each printing plate.

The printing plate thus produced is mounted on the plate cylinder of the printing press. The printing press 1 shown in FIG. 4 is a model diagram of a sheet-fed four-color offset printing press, and its outline will first be explained.

A large number of sheets of printing paper 9 are stacked on the paper stacking table of the feeder 2, and each sheet is sent to the feeder board 3 one by one.
sent upwards. The feeder board 3 transports the printing paper forward, adjusts the registration of the printing paper in the front-rear direction and the left-right direction at the front end thereof, and feeds the printing paper to the printing section at a constant timing.

The printing department has four printing units 10, 20, 3.
For example, printing is performed in cyan in printing unit 10, magenta in printing unit 20, yellow in printing unit 30, and black in printing unit 40.

The configuration of the printing unit is the same for all printing units. Taking the printing unit 10 as an example, the printing unit includes a printing cylinder 11 on which a printing plate is wound and fixed, and a printing plate provided in contact with the printing cylinder 11. It consists of a blanket cylinder 13 that receives ink from the cylinder 11 and transfers the ink to the printing paper, and an impression cylinder 12 that grips the printing paper with its claws and winds and conveys it.Although not shown, the plate cylinder 11 It is equipped with an inking device and a dampening device that supply ink and water to the printing plate fixed to the printing plate.

In order to transfer printing paper between such printing units, transfer cylinders 7, 7, 7 are connected to each impression cylinder 1.
It is provided between 2, 22, 32, and 42. Note that the catch cylinder 8 is provided to deliver the printed paper 9' discharged from the final printing unit 40 to the delivery section 4.

Further, the gripping devices for the printing plates of the plate cylinders 11, 21, 31, and 41 are provided with their phases shifted by a certain angle in the circumferential direction due to the structure of the printing press. , 31, 41, a phase difference occurs in the circumferential direction by a value corresponding to the displacement angle.

The printed paper 9' discharged from the final printing unit 40 is mounted on a chain 5' extending over guide wheels 5, 5 in the delivery section 4 provided adjacent to the printing unit 40. The paper sheets are held in the claws of the holding rod, are conveyed to the paper stacking table 6 by the movement of the chain 5', are released from the holding rod, and are successively stacked on the paper stacking table 6.

The above is the basic configuration of a printing press, and in addition to this configuration, the printing press according to the present invention further includes the following configuration.

That is, as shown in FIGS. 4 and 5, each printing unit 10, 20, 30, 40 has a printing plate P wound and fixed around the circumferential surface of a plate cylinder 11, 21, 31, 41. Registration marks formed in the margins on both sides
Imaging devices 14a and 14b, 24a and 24b, 34a and 34 are placed at positions where M ₁ and M ₂ can be read.
b, 44a and 44b are attached. Since the register marks M ₁ and M ₂ are formed at both ends of the printing plate P, two of these imaging devices, for example 14a and 14b, are provided in one printing unit.

Note that a TV camera using a CCD image sensor, an image pickup tube, etc. can be used as the imaging device.

With such an imaging device, the register marks M ₁ and M ₂ of each printing plate are displayed on the CRT display device one by one, and at the same time, the reference marks are separately displayed.
The mounting position of each printing plate is confirmed by checking the extent to which the register mark of each printing plate overlaps with the reference mark. In other words, if the register marks of each printing plate completely overlap with the reference mark, the printing plates are in register with each other, and on the other hand, if there is a register mark that does not completely overlap, then the It can be determined that the printing plate corresponding to the register mark is not in register.

In order to sequentially display and compare the fiducial mark and the register mark of each printing plate on the CRT display device as described above, it is necessary that the imaging device can always capture images at a fixed position on the printing plate, and that the position of each printing plate is There are problems such as being able to capture images that take phase difference into consideration and how to generate reference marks.

Various methods can be considered to solve this problem, but here we mainly use the methods shown in Figures 4 to 6.
The block diagram shown in the figure will be explained.

That is, in the embodiment shown in FIGS. 4 and 6, the imaging devices in each printing unit are all attached to fixed positions with respect to each plate cylinder, and the image signals from each imaging device are taken in from the printing plate. This is done with a timing shift corresponding to the phase shift of . Further, the image of the reference mark displayed on the CRT display device is printed by the printing units 10, 20, 3.
The image of the registration mark of one printing unit arbitrarily selected from among 0.0 and 40 is used, and the images of the registration marks of other printing units are sequentially synthesized and displayed on this reference mark to confirm the mounting positions of the printing plates. I will do it.

As shown in FIGS. 4 to 6, 51 is a rotary encoder as a pulse generating means that generates pulses according to the operating conditions of the printing press, and is used to capture image information taken by the above-mentioned imaging device. It is provided to determine the timing.
In this embodiment, the rotary encoder 51 is provided on the impression cylinder 12 of the printing unit 10.
Not limited to this position in particular, other impression cylinders,
It can be provided at a position such as the plate cylinder where it 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.

Image signals from each imaging device, pulse signals from the rotary encoder 51, and timing signals from the reference sensor are input to the processing circuit 100.
As shown in FIG. 6, image signals from imaging devices 14a and 14b provided in the printing unit 10 are converted into digital signals by A/D conversion circuits 101a and 101b, respectively, and are further converted into digital signals by a compression circuit 101b.
At 02a and 102b, the signal from the A/D conversion circuit 101a is compressed so that it exists only in the left half area of the CRT screen, which will be described later, while the signal from the A/D conversion circuit 101b corresponds to the right half of the screen. The signal is compressed so that it exists only in the area where the 2
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. Exclusive OR circuit 1
04 is responsible for inverting positive and negative images,
When the switch 105 connected to the other terminal is opened, 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, 1
The image signal from 4b is outputted only for one vertical blanking period at a predetermined timing as will be described later.

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 a counter 107, and since this count corresponds to the rotation angle of the plate cylinder, it is adjusted to a predetermined angle by the image signal capture timing setting switch 109. A value is set, and the comparator 108 compares the count from the counter 107 with the value of the image signal capture timing setting switch 109. When the two match, the comparator 108 outputs a signal for capturing one pulse image signal. is output. Note that the counter 107 uses the signal from the reference sensor 61 as a clear signal, and therefore the counter 107 is cleared by one rotation 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 1.. generation circuit 11
Since the output signal from 3 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 contents of the CRT are displayed. will be changed from time to time. In this invention,
Since the rotation of the plate cylinder is fast and there is no necessity to refresh the displayed image every time the plate cylinder rotates, the output signal from the comparator 108 is not input directly to the generation circuit 113, and the plate cylinder rotates several times. counter 1 in order to open gate 106 once in
10, a comparator 111 and a sampling interval switch 112 are interposed.

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. When they match, the comparator 111 A pulse signal is output from the 1.. generation circuit 113, and by inputting this pulse signal to the 1.. generation circuit 113, the 1.. generation circuit 113 gives a command to the gate 106 to open the gate 106 for only one vertical blanking period.

The image signal output from the gate 106 receives the clock from the clock generation circuit 152 from the counter 1.
The data are sequentially stored in the address of the storage device 153 specified by counting in 51.

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, 44a and 44b are connected to A/D conversion circuits 101a and 101b of 100M, 100Y and 100BK, respectively, and the output of the counter 107 is connected to 100M and 100BK respectively.
It is connected to the comparator 108 of Y, 100BK.

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 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, is adjusted to match the phase difference unique to the printing press. It is necessary to make it different.

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 number of pulses counted 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 the number of pulses counted 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. , 30, 40, printing unit 10
The timing for capturing the image signal is determined by adding or subtracting the number of pulses corresponding to each phase difference from the number set in the timing setting switch 109 of the printing unit 10. This synchronizes the capture of image signals from the imaging devices of each printing unit, and if the printing plates are registered with each other, the images of the registration marks on the CRT screen (described later) will all overlap completely. There will be.

Furthermore, the image signals output from 100M, 100Y, and 100BK are input to a switching circuit 170, and only one of these image signals is selectively output. This switching circuit 170 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 sequentially stored in the storage device 163 by counting the clock generated by the clock generating circuit 162 by the counter 161 and using the counted number as an address signal.

190 is a mixing circuit to which the storage device 153 and the storage device 163 described above are connected, two image signals are input from these storage devices, and a synchronization signal generation circuit is connected to generate a vertical blanking signal and a horizontal blanking signal. is input, the two image signals are combined in this mixing circuit 190, and each CRT 15, 25, 35, 4
The screen of No. 5 is divided left and right, and two images are displayed on one screen.

As seen in FIG. 7, in this embodiment, the image of the register mark based on the image signal from the printing unit 10 is constantly projected as the reference mark m ₁ ', m ₂ ', and the other printing units 20, 30, By projecting the image of the register mark based on the image signal selected by the switching circuit 170 from among the image signals from 40 as adjustment marks m ₁ and m ₂ , when both marks are completely overlapped, the printing plate If the register is correct, and if it is out of alignment, it can be confirmed that the register is not correct.

At this time, if the switch 105 is used to display either the reference mark or the register mark image in positive/negative inversion, confirmation becomes easier.

This check is performed sequentially on all other printing units with one printing unit as a reference (printing unit 10 in this example), and if the printing unit is out of register each time,
The registration of each printing plate can be adjusted by moving the plate cylinder on the adjustment mark side using a conventionally known remote control while looking at the CRT display screen and overlapping the adjustment mark with the reference mark.

A CRT display device for checking this kind of register is
Since many of the current printing presses have register adjustment buttons integrated into each printing unit, in this embodiment, each printing unit has a CRT display device 15,
25, 35, and 45 are shown, but if it is a centralized remote control system, it is sufficient to have one CRT display device near the console.

Also, in this embodiment, a compression circuit and an OR circuit are provided to display two register marks on one CRT screen.
Although a configuration is shown in which the images of M ₁ and M ₂ are displayed in a composite manner, it is possible to display the images of the two register marks M ₁ and M ₂ separately.
It may also be configured to display on a CRT. In this case, the compression circuit and OR circuit are not required, but the number of exclusive OR circuits, gates, and CRTs, and the memory storage capacity are required to be twice as large as in this embodiment.

Furthermore, in this embodiment, the phase shift of the printing plate is electrically corrected and the image signal is captured at a fixed position, but the mounting position of the imaging device is changed in each printing unit according to the phase shift. It is also possible to correct the mechanical structural phase shift by attaching them with different positions.

Further, the means for displaying the fiducial mark and the register mark on the CRT display device is not limited to that of the above embodiment, and the following method may also be used.

For example, a fiducial mark is electrically generated and always displayed on a CRT display, and images of the fiducial mark from the imaging devices of each printing unit 10, 20, 30, 40 are sequentially synthesized onto this fiducial mark. It is also possible to confirm the position of the printing plate by displaying it.

In addition, reference marks are electrically generated and displayed on the CRT display at all times, and the plate cylinders are sequentially stopped at predetermined positions. position), a method may be used in which the image signals are sequentially taken in from the imaging device one plate at a time at those stop positions, and the images are compositely displayed on the CRT display device for confirmation without storing them in memory.

Further, in this description, a sheet-fed four-color printing press is taken as an example, but this method can be similarly applied to other offset multi-color printing presses, such as rotary printing presses.

As described above, if the fiducial mark image and the register mark image are displayed on the CRT display device,
The operator checks the degree of overlap, and if they are completely overlapped, the printing plate of that printing unit is assumed to be installed in the correct position. Using known adjustment means, the position of the printing plate is corrected so that the register mark completely overlaps the fiducial mark.

By carrying out such confirmation and correction for each printing plate, it is possible to align the printing plates with each other, and therefore, it is possible to obtain printed matter that is in the correct register from the time printing is started.

As stated above, according to this invention,
The image displayed on the CRT display allows you to check whether each printing plate is installed in the correct position.
By using this to move the position of each printing plate so that the register mark of each printing plate completely overlaps the constantly displayed reference mark, it is possible to align the printing plates with each other. ,
Since registration is performed without actually printing on printing paper, the time and effort required for registration are greatly reduced, and printing paper for registration is also not required.

Further, according to the present invention, the registration of printing plates can be easily performed as described above without making any major changes to existing equipment, including printing machines, and it is possible to effectively utilize existing equipment. It is extremely practical and has excellent effects.

[Brief explanation of drawings]

The drawings show one embodiment of the invention,
FIG. 1 is a plan view of an offset printing plate on which register marks are formed, and FIG. 2 is an explanatory diagram showing the state of the register marks when the printing plate is not in register.
Figure 3 is an explanatory diagram of the register mark automatic drawing device, Figure 4 is an explanatory diagram of the offset four-color printing machine, Figure 5 is an explanatory diagram showing the relationship between the printing machine and the electric circuit, and Figure 6 is the block diagram of the electric circuit. The diagram, FIG. 7, is an explanatory diagram showing images of a reference mark and a register mark displayed on a CRT display device. 200...Register mark automatic drawing device, 1
4a, 14b, 24a, 24b, 34a, 34
b, 44a, 44b...imaging device, 51...rotary encoder, 61...reference sensor, 15,
25, 35, 45...CRT display device, 100...
...processing circuit, M ₁ , M ₂ ... register mark, M ₃ ...
Dragonfly mark, P...Printed version.

Claims (1)

[Scope of Claims] 1. In a method for checking the installation positions of printing plates attached to the plate cylinders of each printing unit of a multicolor printing machine to align them with each other, Register marks are formed on the surface at a predetermined position and do not fall off during the printing and developing process of the printing plate, and are provided in the margins on both sides of the printing plate surface, and each color printing plate has the pattern and the register marks formed after the printing and developing process. is attached to the plate cylinder of each printing unit, the register mark of the printing plate attached to each printing unit is photographed, and one arbitrarily selected image of the register mark outputted from each printing unit is displayed on the CRT display device. The image of the register mark from the printing unit and the image of the reference mark are combined and displayed, the images of the register mark outputted from each printing unit and displayed on the CRT display device are switched, and they are sequentially compared with the reference mark. A method for confirming the mounting position of a printing plate in a multicolor printing machine, in which the mounting position of the printing plate is confirmed by the overlapping state of an image of each register mark and an image of a reference mark. 2 The image of the reference mark is an image obtained by photographing the register mark of the printing plate attached to one printing unit arbitrarily selected from each printing unit, and the image of the register mark from the other printing unit is 2. The method for confirming the mounting position of a printing plate in a multicolor printing press according to claim 1, characterized in that the images are sequentially switched and compared with the images of the reference marks. 3. Claims characterized in that an image of the fiducial mark is electrically generated and displayed on a CRT display, and images of the register mark from each printing unit are sequentially switched and compared with the fiducial mark. A method for confirming the mounting position of a printing plate in a multicolor printing machine according to item 1.