JPH0259453B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for registering an offset printing press.

Conventionally, among the registration methods for offset printing presses, there have been various attempts to automatically correct registration errors by reading the register marks from the printing plate or printed matter on the printing press, but all of them have been based on the relative position of the register mark and the pattern. Inconsistency caused problems, and automatic correction was practically impossible.

In view of this, the present invention relates to a registration method for an offset printing press that eliminates the discrepancy between the relative positions of the registration mark and the pattern, and enables automatic correction of the registration between multiple colors of the offset printing press.

An embodiment of the present invention will be described below with reference to the drawings.

In the method of the present invention, a register mark is written in a scribing process so that the relative position of the register mark and the pattern match, which enables automatic correction of the register between multiple colors in an offset printing machine. In order to make the relative position accurate, a means for writing a marking line and a means for writing a register mark are incorporated into the same device.

FIG. 1 is a schematic diagram of a fiducial mark writing device _M1 for writing a fiducial mark consisting of a scribe line and a register mark on a printing plate material, for carrying out this method. This device has a machine base 1 equipped with legs 1a, 1a, guide rails 2, 2 are provided along the front and rear ends of this machine base 1, and a slide rod 3 is mounted on the guide rails 2, 2.
The front and rear ends of the slide rod 3 are slidably engaged with each other, and the slide rod 3 is prevented from coming off upward by guide plates 2a, 2a. A marking line and register mark writing section 4 is slidably supported on the slide rod 3. An operation panel P for operating a microcomputer (not shown) is provided on one side of the guide plate 2. By operating the operation panel P, the slide rod 3 is moved along the guide rail 2, and the reference mark writing section 4 is moved along the slide rod. 3, each slides automatically. The reference mark writing section 4 is constructed like a plotter of an automatic drafting machine. To specify the writing position of marking lines and register marks on a microcomputer,
In the case of marking lines, this is done by inputting the marking conditions according to the imposition to be printed, and in the case of register marks, this is done by inputting the paper width and color of the paper used for printing. Also, if you want to register and save input data, register the memory number and use known storage means such as a magnetic disk, magnetic tape, magnetic card, or paper tape to store the input data for one day. After that, you can easily call it up using just the memory number. When using this apparatus _M1 , a printing plate material for printing a film original created in the plate-making process is placed on the machine stand 1, and writing conditions for marking lines and register marks are input into the microcomputer. Based on the input data, a scribing line is first written at the specified position using the scribing line writing head, and then a register mark is written using the register mark writing head.

As described above, the present invention provides a method for marking lines and subsequent registration in the marking process in which marking lines are written on the printing plate material, which are necessary for positioning when printing the original film plate created in the plate-making process onto the printing plate material. A register mark is written at the same time, and registration is performed using this register mark as a reference in subsequent steps. In this manner, by writing the register mark in the scribing process, the relative positional deviation between the register mark and the pattern printed on the number of printing plate materials corresponding to the number of colors is eliminated.

After the printing process is completed, the printing plate is sent to the plate bending process. In this plate bending process, the formation of pin holes as a reference for attaching the printing plate to the plate cylinder and the plate bending in which both sides of the plate are bent are based on the image standard. This work is performed while accurately positioning by reading the register marks written by the device _M1 with optical means.

FIGS. 2 to 5 illustrate the steps for carrying out the method.
Plate bending machine _M2 that bends both ends of the printing plate in the vertical direction
The plate bending machine _M2 has a machine stand 5, and plate bending stands 6, 6 are attached to both sides of this machine stand 5,
Form bending dies 6a, 6a are formed at the upper end thereof. Clamping bodies 7, 7 are provided on the plate bending die 6a to move up and down to clamp the printing plate.
This tightening body 7 is supported by spiral shafts 8, 8, 8 so as to be movable in the vertical direction. Handles 8a, 8a, 8a are attached to the upper end of the spiral shaft 8,
By rotating this handle 8a, the tightening body 7 moves up and down. Note that the tightening body 7 may be moved automatically.

Bending bodies 10, 10 are rotatably supported on the outer surface of the clamping body 7 by shafts 9, 9, and the bending bodies 10 are rotated downward to bend the leading edge of the printing plate P. Bending of the plate is performed by pressing it onto the mold 6a. A positioning moving table 11 is provided flush with the upper surface between the two plate bending tables 6, 6 and is movable in all horizontal directions, and slits 12 are formed in a grid pattern on this moving table 11. The slit 12 is connected to a vacuum source, and the printing plate placed on the moving table 11 is inserted through the slit 12 in the left-right direction in FIG. 2 from between the plate bending die 6a and the clamping body 7. vacuum adsorbed.

The movable table 11 is horizontally supported by a support 13 that holds rotatable balls 13a, 13a, 13a on its upper part, and side walls 11a, 11a attached to two sides of the support 13 have drive pins 14, 14... Spring 15, 15...1 at the tip of 14
5, and this drive pin 14 is supported by a support plate 16 so as to be horizontally movable. and,
The drive pins 14 are each connected to a drive motor (not shown), and are moved horizontally by the drive of the drive motors to move the moving table 11 placed on the ball 13a of the support 13 in any direction within the horizontal plane. let

On the front and rear ends of the moving table 11, there is a machine stand 5.
The sixth
Registration marks written on the printing plate as shown in the figure
Register mark detection sensors 18 and 18 are provided to detect the positions of m ₁ and m ₂ .

In order to match the position of the register mark _m1 , it is convenient to move the register mark detection sensor to an arbitrary position as shown in FIGS. 7 to 9.

That is, the plate bending machine shown in FIGS. 7 to 9
_M3 has a box-shaped casing 21, a machine base 22 is provided inside this casing 21, and this machine base 22
On top are supports 23, 23 similar to the support 13 above.
A movable table 24 is supported by this support body 23 so as to be movable to any position on a horizontal plane, and this movable table 24 is movable by drive pins 25, 25...25 similar to the drive pin 11 described above. be done. Bending mechanisms 26, 26 similar to those described above are formed on both left and right sides of the movable table 24.

Guide rails 21b, 21b are formed at the upper ends of the front and rear side walls of the casing 21, and the front and rear ends of a slide rod 27 are slidably engaged with the guide rails 21b. The portions 28, 28 are slidably supported, and a sensor head 28a is formed at the lower end of the detection portion 28, which accommodates a detection sensor for detecting the register mark.

When the detection unit 28 is provided movably in the horizontal plane in this way, the position of any register mark on the printing plate can be detected.

A printing plate entrance/exit 29 is formed in the front wall 21a of the casing 21, and the printing plate is taken in and out through this entrance/exit 29.

As shown in FIG. 10, the printing plate P has bent portions p ₀ and P ₀ formed at both ends in the vertical direction, and at the same time, pin holes 19, 19,
A pin hole 19 is punched out, and this pin hole 19 is formed by a pin hole puncher 20 attached to the lower end of the clamping body 7.

Next, the operation of the plate bending machine _M2 will be explained.

In FIG. 2, the printing plate is connected to a plate bending die 6a and a clamping body 10 as shown by an arrow A from the right to the left of the figure.
It is inserted through the gap between them and placed on the moving table 11. When the printing plate is placed on the approximate position, a vacuum source is applied to fix the printing plate on the moving table 11 by suction. At this time, before the plate bending process, the horizontal direction (direction other than the vertical direction) of the printing plate
Register marks m ₁ and m ₂ (sixth mark) formed near both ends
) is located almost below the register mark detection sensor 18.

This detection sensor 18 is an optical sensor, and register marks m ₁ and m ₂ formed on both sides of the printing plate.
is a hook-shaped mark, and two sensors 18a, 1 are required to detect the thin lines l ₀ , l ₁ at the intersection of one mark m ₁ .
8b is provided, and a sensor 18c is provided to detect the thin line l ₂ of the other hook-shaped mark m ₂ (11th
figure). The moving table 11 is moved so that the lines l ₀ , l ₁ , l ₂ of the register marks are at the center position of each sensor 18a, 18b, 18c, but this operation is performed by detecting the deviation from each detection sensor. A drive motor (not shown) is actuated by the signal to horizontally move the drive pin 14, thereby automatically performing feedback control.

First, the moving table 11 is moved as shown in FIG.
The left and right thin lines l ₁ and l ₂ of the printing plate P are moved in the left and right direction in FIG _.
the second line so that the thin line _l0 is in the center of the sensor 18a
Moved in the front and back direction of the figure.

As the light source of the detection sensor, any known illumination light source or a light emitting diode is used, and as the light receiving element, a semiconductor light receiving element, a phototube, a photomultiplier tube, or the like is used. That is, as shown in FIG. 12a, the light from the light source 30 is reflected from the surface of the printing plate P and detected by the light receiving element 31. In this case, when the light from the light source hits the thin line l of the register mark, the reflected light Since the voltage of the light-receiving element that receives the light changes in a peak manner, that position is detected as a regular reference position. In addition, as shown in FIG. 12b, the light source 3
Lenses 32, 32 may be provided between the light receiving element 31 and the reflective surface, and between the reflective surface and the light receiving element 31. Further, as shown in FIG. 13a, two light-receiving surfaces 33 and 34 are arranged in parallel, and a mark on the printing plate illuminated using a lens system is imaged onto the light-receiving surfaces 33 and 34.
The (thin) line of the register mark from the light intensity balance of 34
Detecting the position of will improve accuracy. That is,
As shown in FIG. 13c, the output power corresponding to the position of the (thin) line l on the light receiving surface 33 is as shown in the solid line graph _g1 , and the output voltage corresponding to the position of the (thin) line l on the light receiving surface 34 becomes like a chain line graph g ₂ , and the intersection C of both graphs g ₁ and g ₂ corresponds to the center position of the (thin) line l. As the light-receiving surface used for this purpose, the end face of a light guide made of a bundle of optical fibers, a semiconductor light-receiving element manufactured by arranging a plurality of light-receiving surfaces, and phototubes are used. Note that the light receiving surfaces may be round light receiving surfaces 35 and 36 as shown in FIG. 13b. The register mark used for reading can be detected on a printing machine if it is 1/100 mm or more, preferably 5/100 mm or more, but this register mark is also read when the printing press rotates, so it is 0.2 mm. It is preferable to have a thickness of the above thickness. It is also possible to increase the contrast by applying special ink. In this way, by moving the moving table 7, the printing plate is placed at the reference position.

The hook-shaped register mark detected by the sensor described above is written simultaneously with the marking line by the marking device of the present invention, but instead of detecting this register mark, the register mark detected by the conventional printing plate is used. Positioning may be performed by detecting a reference fine line such as a register mark for printing or a register mark for pasting in a plate-making process. In this case, unlike the hook-shaped mark, the thickness of the reference thin line may be 1/100 mm or more, preferably 5/100 mm or more. Of course, in this case as well, a hook-shaped mark for automatic registration on the printing press is included.

Next, a plate bending operation is performed to bend both ends of the printing plate in the vertical direction. This is done by lowering the clamping body 7 by rotating the handle 8a and pressing both ends of the printing plate onto the plate bending die 6a. , by rotating the folding body 10 downward. As the tightening body 7 descends, the pin hole puncher 2
0 also descends, so the pin hole 19 is bent at the same time as the plate is bent.
(Fig. 10) is formed. This pin hole 19 is
When attaching the printing plate P to the plate cylinder 40 shown in FIG. 14, positioning pins 41 formed at both ends of the plate cylinder,
41 and 42. This pin hole 19 is provided for positioning the printing plate P in the left-right direction when it is attached to the plate cylinder. Namely. The printing plate P is positioned in the vertical direction by bending both ends of the printing plate, but since displacement in the horizontal direction cannot be controlled, it is necessary to engage the positioning pin 41 with the pin hole 19. It is. Since the pin holes 19 are drilled at positions that are positioned based on the pattern reference, the accuracy is considerably improved compared to the pin holes that are drilled in advance during printing.

When the plate bending process is completed, Fig. 15 and Fig. 1
As shown in Figure 6, the printing plate P is attached to the plate cylinder 40. First, one of the bent portions _P0 (cusp) is inserted into the cusp 40a of the plate cylinder 40 (Figure a).
After wrapping the printing plate P around the circumferential surface of the printing plate P while rotating, the other side (buttock) of the bent part P ₀ is attached to the buttock 4 of the plate cylinder.
It is inserted into the opening 43a of the winding shaft 43 through the screw 0b (Figure B), and is tightened by rotating it (Figure C).

In the plate bending machine _M3 shown in FIGS. 7 to 9, the detection writing section 28 is moved on the printing plate by moving the slide rod 27 along the guide rail 21b in accordance with the position of the register mark. Its operation is the same as that of the plate bending machine _M2 described above, except that it moves in the vertical direction and the detection writing section 28 is moved directly on the slide rod 27 in the lateral direction of the printing plate.

In this way, this plate bending machine performs plate bending and pin hole drilling on the number of printing plates according to the number of colors, based on the register mark burned into the printing plate. The bending positions, etc. are exactly the same, and the accuracy of each is much better than the conventional method. According to this method, even if mechanical errors in the set printing plate, plate bending device, and mounting to the plate cylinder are taken into consideration, the deviation can be kept within ±0.3 mm, which can be automatically corrected by the printing press. can.

Register mark reading is divided into two types: reading from the plate cylinder and reading from the printed material.

When reading from a plate cylinder, optical sensors 50, 50 are provided at positions where the printing surface of each plate cylinder is desired, as shown in FIG. It will be installed in the department.

A reference point setting section 51 is provided on the rotation shaft 40a of the plate cylinder 40, and the reference point setting section 51 is connected to a setting ring 52 formed on the rotation shaft 40a, and when the setting ring 52 reaches a preset reference position. It consists of a sensor 53 that sometimes detects this. This sensor 53 is connected to a reference point signal generator 63.

As shown in FIG. 18, the left and right optical sensors 50, 50 have a reference point S set by a reference point setting unit 51, a horizontal thin line 54 of the register mark _m2 , and an inclined thin line forming an angle θ with this horizontal thin line 54. Find the distance to 55. When the registration is correct, the distances from the reference point S of each mark on each plate cylinder to each thin line 54, 55 are equal. At this time, the state of the register marks on each plate cylinder is as shown in FIG. 18a.

Between one plate cylinder and another plate cylinder, with respect to the distance from the reference point S, only in the vertical direction, as shown in Fig. 18b.
If an error of E ₁ is detected, the signal passes through the mark detection circuits 56 and 56 and is input to the vertical error amount detection circuit 57, and the output signal from this circuit 57 is used to control the plate cylinder phase correction motor drive circuit. 58
is activated, and the rotational phases of each plate cylinder are matched by known means.

Also, the register marks m ₁ on both the left and right sides of a certain plate cylinder,
When m ₂ is equally displaced in both the vertical and horizontal directions as shown in Fig. 18c, the vertical displacement E ₁ is corrected as described above, and the horizontal displacement E ₂ ( l ₂ ″−l ₂ ″=l ₂ ″−l ₂ −E ₁ =l ₃ tan
(90° θ)) is detected by the left-right direction error amount detection circuit 59, and this detection signal is sent to the left-right direction plate motion drive circuit 60.
is input, and the plate cylinder itself is moved and corrected in the left and right direction by known means.

Registration marks on either the left or right side of one plate cylinder
m ₁ is in the standard state (Fig. 18a) and the other is 18c
In the state shown in the figure, the printing plate P is attached to the plate cylinder in a twisted state, so the twist error (combination of E ₁ and E ₂ ) is detected by the twist amount detection circuit 61. The signal from this detection circuit 61 is input to a motor drive circuit 62 for correcting the twist.

The amount of twisting is corrected by a known twisting device 70 as shown in FIG. That is,
The operation side of the plate cylinder 40 is movable back and forth with respect to the driving side (gear side), and this movement is achieved by a rotation bearing 71 mounted eccentrically upward on the rotation shaft 40a of the plate cylinder, by the circuit 62. Rotating drive shaft 72
This is done by slightly rotating the
A threaded portion 71a is formed at the lower part of the rotation bearing 71, and this threaded portion 71a is connected to the threaded portion 7 of the drive shaft 72.
2a, and as the drive shaft 72 rotates, the rotation bearing 71 rotates about its center O, causing the plate cylinder to move slightly in the left-right direction in the figure. This correction causes the contact point between the plate cylinder and the blanket cylinder to shift, which is undesirable in terms of mechanical structure, so the amount of correction is usually ±
Pressed within 0.3mm.

After the plate cylinder is corrected, the register marks m ₁ and m ₂ are further read, and if the amount of correction is inappropriate, a correction signal is issued again, and thus feedback control is performed.

When reading register marks from a printed book, a total of four sensors are provided on the front and back sides of one plate cylinder in the web path section. In this case, if the register marks overlap, it will be inconvenient to read, so the register marks are printed in multiple colors at regular intervals.

Since the registration mark is written on the printing plate before exposure, any material that can mask the light during exposure can be used on a positive PS plate, and is printed using water-based oil-based ink, for example. Alternatively, printing may be performed using a material that can directly serve as a printing area, such as an oil-based lacquer. In addition, in the case of a negative PS plate, it is best to form only the registration mark by attaching a light-transmissible film to the plate and printing it.

With this configuration, it is possible to write the register mark for automatic registration on the printing press at a relative position that matches the pattern,
Furthermore, since the plate is bent and the plate mounting pin holes are drilled based on this register mark, the accuracy of mounting on the plate cylinder is dramatically improved, and it is now possible to automatically correct registration errors in twisting, which were difficult to correct in the past. This makes it possible to preset and automatically correct the register for starting printing. In addition, since the work of writing marking lines on conventional printing plates is automated, there is no need for a huge number of marking pads, and the marking accuracy is significantly improved compared to the conventional manual method.

[Brief explanation of drawings]

FIG. 1 shows a reference mark writing device according to the present invention,
Fig. 2 is a perspective view of a plate bending machine for carrying out the method of the present invention, Fig. 3 is a view taken along the X arrow in Fig. 2, Fig. 4 is a partial sectional view of the plate bending machine, and Fig. 4 is a cross-sectional view, FIG. 6 is a plan view of the printing plate, FIG. 7 is a perspective view of another plate bending machine, FIG. 8 is a cross-sectional view of the plate bending machine shown in FIG. A vertical cross-sectional view of a plate bending machine, FIG. 10 is a perspective view of a printing plate after bending the plate, FIG. 11 is an explanatory diagram of the relationship between the register mark and the sensor, and FIGS. 12 a and b are schematic configuration diagrams of the sensor. Fig. 13 is an explanatory diagram of the detection principle of the sensor, Fig. 14 is a perspective view of the plate cylinder, Fig. 15 and Figs. 16a, b, and c are diagrams of the process of attaching the printing plate to the plate cylinder, and Fig. 17 is the amount of registration error. A modified block diagram, FIG. 18 is an explanatory diagram of its principle, and FIG. 19 is a perspective view of the lifting device. DESCRIPTION OF SYMBOLS 1... Machine stand, 2... Guide rail, 3... Slide rod, 4... Reference mark writing part, 6... Plate bending table, 7... Tightening body, 10... Bending body, 11...
...Moving table, 13...Support, 15...Spring, 18...Detection sensor, 19...Pin hole, 20
...Pin hole puncher, 21 ...Casing, 2
4...Moving table, 25...Bending mechanism, 27
...Slide rod, 40...Plate cylinder, 41, 42...
Positioning pin, 50... optical sensor, 51... reference point setting section.

Claims (1)

[Scope of Claims] 1. A number of printing plate materials corresponding to the number of colors are prepared, and marking lines necessary for positioning when printing a film original created in the plate-making process onto each drawing plate material are drawn on the printing plates. After marking lines and register marks for automatic registration on the printing press are written on the printing plate material by means of writing on the material, the printing plate created by baking the printing plate material is attached to the plate cylinder, and the above-mentioned A registration method for an offset printing press, characterized in that the registration mark is read by an optical means using the registration mark as a reference, and automatic registration of vertical, horizontal, and twist amounts is performed.