JP3355631B2 - Laser plate making apparatus and plate making method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate making apparatus and a plate making method for obtaining a plate of a plate cylinder by a laser beam from a laser source.

[0002]

2. Description of the Related Art The present applicant has previously described Japanese Patent Application Laid-Open No. 2-139238.
Japanese Patent Application Laid-Open Publication No. H11-216, proposes an intaglio plate cylinder in which a plate made of a thermoplastic resin is irradiated with a laser beam using a laser source to form a concave portion corresponding to the density of an image.

An outline of the configuration disclosed in the above publication will be described with reference to FIG. FIG. 12 is a conceptual diagram of an optical system showing a method of forming a pattern of the plate 2 wound around the plate cylinder 1. The plate cylinder 1 is a metal cylinder, and a synthetic resin is formed along the outer diameter of the plate cylinder 1. The plate 2 is wound and fixed to a main screw formed in the plate cylinder 1 with a flathead screw or the like. This fixing method can be appropriately selected. For example, an adhesive layer can be formed on the back surface of the plate and fixed to the plate cylinder 1.

The material of the plate 2 is preferably a thermoplastic resin having a relatively narrow melting point distribution range, being hard when cured, and being scattered or sublimated at a low temperature when melted, such as polyethylene resin, acrylic resin, and polypropylene. What contains about 20% carbon in resin is used. or,
The thickness of the plate 2 is selected to be about 200 microns.

[0005] The plate cylinder 1 is connected to a plate cylinder rotation motor described later, and the plate cylinder 1 is rotated in the direction of arrow B.

FIG. 12 is a conceptual diagram for forming a depression 4 in a plate 2 using a semiconductor laser 3 of about 1 W.

A video input signal 5 captured by an image scanner or the like is supplied to a semiconductor laser 3 and a drive current or P
It is turned on and off by the video input signal 5 converted into a CM, and is directly modulated. Therefore, the laser beam emitted from the semiconductor laser 3 blinks in synchronization with the video input signal 5. The laser beam emitted from the semiconductor laser 3 is converted into parallel light by a collimating lens 6 and is irradiated via a focusing lens 7 so as to focus on the surface position of the plate 2.

The laser block 8 including the semiconductor laser 3, the collimator lens 6, and the focus lens 7 is initially focused on a predetermined position on the leftmost side of the plate cylinder 1. Since the plate cylinder 1 is rotated in the direction of arrow B by a plate cylinder rotation motor, which will be described later, when the plate cylinder 1 is rotated once, the depression 4 for one track along the circumference is scattered by the laser beam. Thus, a depression 4 for a predetermined track is formed. Next, the laser block 8
Is moved in the axial direction of the plate cylinder 1 by one pixel to scatter the synthetic resin, thereby forming a predetermined depression 4 for two tracks. If such scanning is sequentially performed over the entire surface of the plate cylinder 1, the synthetic resin material forms a pattern of depressions 4 corresponding to the density of the video input signal 5.

That is, the plate cylinder 1 is irradiated with a laser beam through the focus lens 7, focuses on the surface of the synthetic resin plate 2, melts the plate surface, and scatters or sublimates the synthetic resin. In this case, by modulating the laser or changing the laser irradiation time for one dent 4, the dent amount and size of the plate material scattering or sublimating are adjusted to obtain a dent 4 having a volume corresponding to the gradation. That is, as shown in FIG. 12, the amount of the plate material scattered by the laser beam has a depth d depending on the density of the image input signal.
Or the area S is changed.

FIGS. 13A to 13D show the gradation and signal change state of the depression 4 formed on the gravure plate 2 by the laser beam, and 9 in FIGS.
~ 3/4, 3/4 ~ 1/2, 1/2 ~ 1/4, 1/4 ~
The area S of the depression 4 made by the laser beam when the gradation is divided into four levels such as 0 is shown, and 10 shows an example of the waveform in the on / off state.

As can be seen from this waveform, the recess 4 is formed only while the semiconductor laser 3 irradiates the plate 2 with the laser beam.
Is formed, it is understood that the depressions 4 having different areas S can be obtained by controlling the ratio of the on / off time of the laser beam, and the area gradation can be expressed.

[0012]

In the conventional configuration described above, for example, when the dot area ratio in FIG. 13D is considered to be in the range of 1/4 to 0, the ON period of the laser beam is the same as the ON period of the laser beam in FIG. 13A. Since it is 1/4 to 0, gradation is expressed by a waveform in an off period of 3/4 to 1.

For this reason, when the waveform 10 of the laser beam is off, the depression 4 of the pattern is not formed and the area 9 is as shown in FIG.
It becomes small like D, and when we look at the plate making time during this time,
Waste time will increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a laser plate making apparatus and a plate making method capable of shortening a plate making time.

[0015]

According to the first aspect of the present invention, a plate 2 is irradiated with a laser beam 11 from a laser source 3 to form a gravure plate having a pattern corresponding to an image to be printed on the plate 2. In the laser plate making apparatus, scanning deflecting means 12 and 13 for high-speed fine scanning of the laser beam 11 in a direction tangential to the outer periphery of the plate cylinder 1 around which the plate 2 is wound or in a direction of a rotation axis;
The pattern is represented by m × n (m and n are arbitrary natural numbers, where n = m
+1) a plurality of blocks 45 of pixels 4 (45a to 45d,
A pattern geometric transformation image processing means for dividing into 50a to 50i) and a block 45 (45a to 45d, 50a to 50d)
i) block 4 based on the gradation corresponding to the area ratio of each pixel 4
And control means for controlling the scanning method of the scanning deflecting means 12 and 13 so that the laser beam 11 is continuously scanned on each pixel 4 of 45 (45a to 45d, 50a to 50i). This is a laser plate making device that performs One block 45 of the m × n pixels 4 according to the present invention is characterized in that the arrangement in the tangential direction of the outer periphery of the plate cylinder 1 is aligned and the rotation axis direction is shifted by 1 / n. A laser plate making apparatus according to claim 1.
According to a third aspect of the present invention, the prepress image data input to the system controller is converted into a plurality of blocks 45 (4) of m × n (m and n are arbitrary natural numbers, where n = m + 1) pixels 4.
5A～45d, a process ST ₂ for processing pattern geometric transform image into 50a~50i), block 45 (45A
45d, a process ST ₃ for detecting the highest gray level in the plurality of pixels 4 in 50A～50i), depending on the stage of the detected detection process tone, reorder data in response to the scanning in the block a process ST _4, the block 45 on the basis of the rearranged data (45a~45d, 50a~5
A process ST ₄ which generates a scanning signal 0i) in the block 45 (45a to 45d, the pattern block 45 which forms the plate 2 turned based plate cylinder 1 wound on the scanning signal in 50a~50i) (45a~ 45d, is obtained by a plate-making method characterized by comprising more the processes ST ₅ to perform plate making by scanning the inside 50a~50i).

[0016]

According to the laser plate making apparatus and the plate making method of the present invention, when a predetermined pattern of depressions is formed on a plate using a laser beam, a scanning method is performed in accordance with the gradation of each block divided into a plurality of blocks. Is controlled so that the pattern making time can be reduced in the case of making a pattern within a predetermined area.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a laser plate making apparatus and a plate making method according to the present invention will be described in detail with reference to FIGS.

FIG. 1 is a schematic diagram showing the configuration of a laser plate making apparatus according to the present embodiment, wherein 1 is a plate cylinder, and the outer peripheral surface of the plate cylinder 1 is made of the same synthetic resin as that described in FIG. Plate 2 is stuck and fixed. Reference numeral 15 denotes a rotation axis of the plate cylinder 1,
A motor shaft of the plate cylinder rotating motor 16 is coupled to the motor shaft via a pulley, which will be described later. An encoder 17 is attached to the motor shaft, and the rotation speed and the like of the plate cylinder 1 are detected. Is supplied with an output from the encoder 17.

The ball screw 18 is disposed parallel to the axial direction of the plate cylinder 1, and a laser block moving motor 19 is coupled to the ball screw 18 via a coupling or the like. A moving element 20 is screwed into the ball screw 18, and the laser block 8 moves in the axial direction of the ball screw 18 by the moving element 20, and forms a depression 4 on the plate 2 of the plate cylinder 1 by the laser beam 11.

From the system controller 14, the above-described plate cylinder rotation motor 16 and laser block moving motor 19 are provided.
Is supplied to rotate the plate cylinder 1 in the radial direction and move the laser block 8 in the axial direction of the plate cylinder 1 to form a predetermined depression 4 on the entire surface of the plate 2, Is formed.

As shown in FIG. 2, an X-axis and Y-axis drive motors 24 and 25 for driving the semiconductor laser 3, a collimator lens 6, and polarizing elements 12 and 13 such as galvanometer mirrors, and a focusing lens 7 are provided in the laser block 8. Is built-in.

That is, the semiconductor laser 3 is turned on and off by a laser driver 23 controlled by a system controller 14, and the laser beam 11 emitted from the semiconductor laser 3 is converted into parallel light by a collimating lens 6. , And irradiates the carbal mirror 12. First
Is swung in the Y-axis (circumferential direction of the plate cylinder 1) by the Y-axis drive motor 25, and the second galvano-mirror 13
Is reflected by the X-axis driving motor 24 in the X-axis (the axial direction of the plate cylinder 1), and focused on a predetermined position of the plate wound around the plate cylinder 1 by the focus lens 7 to form the plate 2. A depression 4 is formed.

The first and second galvano mirrors 12, 1
3 is supplied from the system controller 14. Of course, the system controller 14
Is supplied from an image data source 26 for forming the plate 2 previously stored in a ROM or a RAM.
Further, in the above-described configuration, the galvano mirror 12 is used as the polarizing element, but an acousto-optic polarizing element (AO
D), an electro-optic polarizing element (EOD) or the like may be used,
Any deflecting means that can deflect the laser beam in the X and Y-axis directions of the plate cylinder 1 at high speed may be used.

FIG. 3 shows a specific configuration example of the laser plate making apparatus described in the above conceptual diagram. In FIG. 3, reference numeral 30 denotes a plate making machine rotating base 31 on a substantially rectangular steel plate.
And a laser block moving unit 32. The plate cylinder rotating part 31 has left and right side walls 33L, 33R formed in a substantially U shape.
A substantially cylindrical plate cylinder 1 is rotatably pivoted between the base and a base 30.
The laser block 8 includes a semiconductor laser 3 and is driven by a plate cylinder rotation motor 16 disposed thereon, and moves along a guide portion 34 disposed along the axial direction of the plate cylinder 1. It is made to do.

A synthetic resin plate 2 is wound and fixed along the outer periphery of the cylindrical portion of the plate cylinder 1. Metal caps 35L and 35R are fitted on the left and right sides of the plate cylinder 1, respectively.
Shafts 36L, 36R formed integrally with L, 35R are pivotally attached to left and right side walls 33L, 33R. Shaft 36
R is a plurality of pulleys 37, 37 ‥‥ and belts 38, 38 ‥
Plate cylinder rotation motor 1 fixed on base 30 through ‥
6, the plate 2 wound around the plate cylinder 1 via the pulley 37 and the belt 38 rotates in the arrow A or B direction.

In the laser block moving section 32, a substantially rectangular sub-base 39 is placed on a rectangular step formed on the left and right side walls 33L and 33R of the base 30.
The guide part 34 is formed on the upper part 9. Sub-base 3
The bearings 40L and 40R are planted on the bearing 9, and the ball screw 18 of the laser block moving unit 32 is bridged between the bearings 40L and 40R.
At 9, the ball screw 18 is driven to rotate. That is, the ball screw 18 is engaged with the shaft of the laser block moving motor 19 by the coupling shaft coupling 41 to drive the ball screw 18.

A movable member 20 is screwed into the ball screw 18, the movable member 20 and a laser block mounting base 42 are fixed by an arm 43, and the laser block 8 is mounted on the laser block mounting base 42. As the laser block 8 moves in the axial direction of the plate cylinder 1 along the guide portion 34, the laser beam 11 emitted from the semiconductor laser 3 in the laser block 8 emits X and The depression 4 can be formed so as to face in all directions of the Y axis.

A method for forming a gravure plate 2 using such a laser plate making apparatus will be described with reference to the pattern forming method shown in FIG.

FIG. 4 shows a pattern of the depressions 4 formed on the sheet-like plate 2. A predetermined number of blocks 45 a, 45 b, 45 are formed on the plate 2.
c, 45d}. One of these blocks
The block 45 is configured by, for example, setting the number of dots in the X-axis direction (the axial direction of the plate cylinder 1) and the Y-axis direction (the circumferential direction of the plate cylinder 1) in units of 3 × 4 pixels (hereinafter referred to as dots). I have. The size of one dot is, for example, about 125 μm × 125 μm.

In the Y-axis direction, dot depressions 4, 4,
‥‥ are aligned and arranged in the X-axis direction.
Are displaced by １ ／ L of the length L = 125 μm in the Y-axis direction on the stairs. That is, the blocks 45a and 45c are arranged in the X-axis direction in units of one block 45 of 3 × 4 dots as described above, and the blocks 4a are arranged in the Y-axis direction.
The plate 2 on which a predetermined image is formed by arranging in a matrix as 5a, 45b # is produced.

In the above example, 3 × 4 dots are divided into 4 blocks.
However, if m and n are arbitrary natural numbers, m
× n dots (provided that (n = m + 1), where n is the number of gradations, and that they can be arranged in the X-axis direction) in one block 45
It is obvious that the pattern can be configured as follows.

The scanning in the block thus formed is performed by a galvanomirror 1 which is a polarizing means of a high-speed micro-scanning optical system.
Performed in steps 2 and 13. The movement from the block 45a to the block 45c (X-axis direction) is performed by the laser block moving motor 19, and the movement from the block 45a to the block 4c is performed.
The movement in the direction 5b (Y-axis direction) is performed by the plate cylinder rotation motor 16.

FIGS. 5 to 8 schematically show a scanning method for changing the scanning of the carbanomirrors 12 and 13 in the block 45 in accordance with the gradation in the block.

FIG. 5 shows that the dot area ratio shown in FIG.
Galvano mirror 1 that corresponds to the gradations of up to 3/4
Using 2 and 13, four scans are performed in the Y-axis and X-axis directions.
That is, in the first scan shown by the solid line,
The inside of the block is continuously scanned in the axial direction during the on-period of the laser beam 11, and then the galvanomirror 13 for the X-axis is shaken by one dot in order to similarly perform the second scanning indicated by the broken line.
Scanning in the Y-axis direction is performed by the galvanometer mirror 12 for three dots. Similarly, the third and fourth scans are performed as indicated by the one-dot and two-dot chain lines. The time reduction efficiency in this case is 1, as in the conventional case.

Next, in the case where the dot area ratio corresponds to the gradation of 3/4 to 1/2 corresponding to FIG. 12B shown in FIG. 6, the laser beam 11 is turned on, and the depression 46a is drawn in the galvano mirror in the Y-axis direction. 12 is formed by shaking. Next, at the moment of the off period of the laser beam 11, the galvano mirror 13 is polarized by three dots in the X-axis direction, and at the next moment, the laser beam 11 is turned on to polarize the galvano mirror 12 in the Y-axis direction to form the depression 46b. . In this way, the conventional laser beam off period t can be used effectively. Furthermore, laser beam 1
The galvano mirror 13 is polarized by one dot in the minus X-axis direction at the moment of the off period of 1 and the laser beam 11 at the next moment is changed.
Is turned on, and the galvanomirror 12 is polarized in the Y-axis direction to form a depression 46c. Similarly, the instantaneous galvano mirror 13 is polarized by one dot in the minus X-axis direction during the off period of the laser beam 11, the next instantaneous laser beam 11 is turned on, and the galvano mirror 12 is swung in the Y-axis direction to form a depression 46d. By doing so, the depressions 46a, 46
b, 46c and 46d are formed.

Next, if the second scanning indicated by the broken line is performed based on the same principle as described above, the depressions 46e, 46f, 46
g, 46h are formed.

Further, if the third scan indicated by the alternate long and short dash line is performed based on the same principle as described above, the depressions 46i, 46j, 4
6k, 46L are obtained. In this case, 12
The scanning of all the dots requires only three scannings, and the efficiency of time reduction is 3/4 of that in FIG.

FIG. 7 corresponds to the gradation in which the dot area ratio corresponding to FIG. 12c is 1/2 to 1/4.
The depressions 47a, 47b, 47c, 47d,
As shown by solid lines 47e and 47f, galvanomila 12
And 13 and then scanning with a galvano mirror as shown by the dashed line to form the depressions 47g and 47g.
h, 47i, 47j, 47k, and 47L are formed. In this case, scanning of one block 45 requires only two scans, and the efficiency of time reduction is half that of the case of FIG.

FIG. 8 corresponds to FIG. 12D, and corresponds to a gray scale in which the dot area ratio is ４ to 0.
The depressions 48a, 48b, 48c, 48 are operated in the same manner as in FIG.
d, 48e, 48f, 48g, 48h, 48i, 48
By scanning the j, 48k, and 48L with the galvanomirrors 12 and 13 as indicated by solid lines, one block can be scanned at a stroke. For this reason, the efficiency of time reduction is reduced to 1/4 as compared with FIG.

An operation for making a gravure plate as shown in FIG. 9 by the pattern forming method of the above-described method will be described with reference to a flowchart of FIG.

FIG. 9 shows, for example, blocks 50a to 50i.
Block 50a in which each gradation has a dot area ratio of 1 to 3/4 shown in FIG. 5 and a gradation in which the dot area ratio is 3/4 to 1/2 shown in FIG. Blocks 50b, 50d, and 50e, and blocks 50c, 50f, and 50b of which the dot area ratio shown in FIG.
50g, 50h and the dot area ratio shown in FIG.
It is assumed that it is composed of blocks 50i of up to gradation.

FIG. 10 is a flow chart of the deflecting means of the system controller 14 at the time of high-speed micro-deflection described with reference to FIG.
Plate making image data such as cyan C, magenta M, yellow Y, and black K read from storage means such as AM is input to the system controller 14 (first step S).
T ₁ ).

Next, in the system controller 14, geometric conversion image processing is performed on the block-based patterns 50a to 50i as shown in FIG. 9 based on the plate making image data (second step ST ₂ ).

Next, in a third step ST ₃ , the system controller 14 sets each block 5
Read data of one block from 0a to 50i,
The one with the highest gradation in one block is detected, and if it is not detected, it is returned to its original state.
It proceeds to step ST _4.

[0045] In the fourth step ST ₄ block 50a~
The data in the block is rearranged according to each stage in 50i. For example, the one shown by the block 50a corresponds to FIG. 5, and four scans are sequentially performed in the Y-axis direction, so that data rearrangement is not necessary. However, the block 50b corresponds to FIG. Next to plate making of 46a, dent 4
Next to 6b, it is necessary to rearrange the data in accordance with the scanning from 46c to 46d. In the same scan, 46e ~
The data is arranged in the order of 46h and 46L, and the data is arranged in the order of 46i to 46L. Similar rearrangement is performed for each of the blocks 50c to 50i.

In accordance with the rearranged plate making data, data for deflecting the X and Y axis galvanomirrors 12 and 13 is generated, and a Y axis drive motor 25 for driving the galvanomirrors 12 and 13 in the laser block 8 is provided. It is supplied to the X-axis drive motor 24.

The fast fine scanning within the block 50a~50i is performed by the fifth step ST ₅ in this manner.
The movement between the blocks in the direction from the block 50a to the block 50b is performed by the system controller 14
Is controlled by the system controller 14, and the inter-block movement in the direction from the block 50a to the block 50d is performed by controlling the motor 19 for moving the laser block by the system controller 14.

The last block 50 in the sixth step ST ₆
determines whether or not i, which proceeds to a seventh step ST ₇ by the rotation of the last block is unless as stated above motor 16 or the motor 19 back to the beginning of the third step ST ₃ performs movement between the blocks . In this case, plate making may be performed for each block from either the X-axis direction or the Y-axis direction of the plate cylinder 1. Further, if the last block 50i leads to step ST ₈ end the plate-making ends.

Since the plate making apparatus of this embodiment is constructed and operated as described above, the shorter the image data density (lower gradation) as shown in FIG. In contrast to conventional plate making, which required four scans (see FIG. 5),
Only one scan is required. This becomes natural considering that the plate making time is proportional to the total amount of energy given to the plate material by the laser. In addition, high-density (high-gradation) noisy image data and the like can be effectively shortened in plate making time by performing smoothing.

In the above example, the block configuration of m × n (m + 1) has been described. However, more simply, the galvanomirror of the high-speed micro-deflecting means of the laser block 8 is set only in the axial direction of the plate cylinder 1 and m × (number of column data) Note that m corresponds to the number of dots and is an arbitrary natural number. ｝ Can be one block.

In the above-described example, the case where dots (recesses) having the same gradation are formed between the blocks has been described. However, the scanning method for the case where the gradation to be made in the blocks is different will be described with reference to FIG.

In FIG. 11, one block is composed of 3 × 4 pixels (dots) 51a to 51L, and the area ratio of each dot is distributed at a gradation of 3/4 to 1/2. I do. Here, a depression 51k where the area ratio of one dot is 3/4
Is the highest gradation (maximum area ratio dot).

In the scanning in this case, the semiconductor laser 3 is turned on by forming the first depression 51a, and even after the semiconductor laser 3 is turned off, the Y-axis galvano mirror 12 is moved to the position where the head 52 of the depression 51b comes. X after slightly deflected in the Y-axis direction of
In order to deflect the shaft galvanomirror 13 by shaking it in the X-axis direction of the plate cylinder 1 and to turn on the semiconductor laser 3 in the Y-axis direction again in order to make the second depression 51b, a dot having a predetermined area ratio is formed. Then, scanning is performed in the Y-axis direction with the semiconductor laser 3 turned off, and when the head comes to the position of the head 53 of the third recess 51c, the galvanomirror 13 is deflected in the negative X-axis direction. Thereafter, after the third dent 51c is made by the same scanning,
The plate 51d may be made in the same manner.

Similarly, the scanning indicated by the dashed line and the scanning indicated by the dashed line may be performed in the same manner as in FIG.

According to the present invention, a micro-deflection is performed in a predetermined direction by effectively utilizing the off-time during which the semiconductor laser does not form a plate, so that a plate-making apparatus and a plate-making method capable of shortening the plate-making time can be obtained.

[0056]

According to the laser plate making apparatus and the plate making method of the present invention, it is possible to obtain a plate making time that can be shortened in accordance with the gradation of the plate to be made.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a laser plate making apparatus of the present invention.

FIG. 2 is a configuration diagram of a laser block used in the laser plate making apparatus of the present invention.

FIG. 3 is a perspective view showing a specific configuration of the laser plate making apparatus of the present invention.

FIG. 4 is a pattern configuration diagram of a block used in the laser plate making apparatus of the present invention.

FIG. 5 is an explanatory diagram of a first scan in a block used in the laser plate making apparatus of the present invention.

FIG. 6 is an explanatory view of a second scan in a block used in the laser plate making apparatus of the present invention.

FIG. 7 is an explanatory view of a third scan in a block used in the laser plate making apparatus of the present invention.

FIG. 8 is an explanatory view of a fourth scan in a block used in the laser plate making apparatus of the present invention.

FIG. 9 is a pattern of a plate showing an example of a laser scanning method by the laser plate making apparatus of the present invention.

FIG. 10 is a flowchart for explaining the operation of the laser plate making apparatus of the present invention.

FIG. 11 is another pattern showing a scanning method in a block of the laser plate making apparatus of the present invention.

FIG. 12 is an optical system conceptual diagram showing a conventional laser scanning method.

FIG. 13 is an explanatory diagram showing a change of a signal according to a gradation at the time of plate making and four-stage division according to the gradation.

[Explanation of symbols]

 Reference Signs List 1 plate cylinder 2 plate 3 semiconductor laser 8 laser block 12, 13 galvanomira

Claims (3)

(57) [Claims] 1. A laser plate making apparatus for irradiating a plate with a laser beam from a laser source and making a gravure plate having a pattern corresponding to an image to be printed on the plate, wherein a plate cylinder 1 on which the plate is wound is provided. Scanning deflecting means for performing high-speed micro-scanning of the laser beam in the outer peripheral tangential direction or the rotation axis direction, and mxn (m and n are arbitrary natural numbers, n
= M + 1) pattern geometric conversion image processing means for dividing into a plurality of blocks of pixels, and the laser beam is continuously applied to each pixel in the block based on a gradation corresponding to an area ratio of the pixel in each block. Control means for controlling a scanning method of the scanning deflecting means so as to perform scanning. 2. The block of m × n pixels is aligned in the tangential direction of the outer periphery of the plate cylinder, and the rotation axis direction is 1 unit.
2. The laser plate making apparatus according to claim 1, wherein the arrangement is shifted by / n. 3. The plate making image data input to the system controller is represented by m × n (m and n are arbitrary natural numbers, where n = n).
(m + 1) a process of performing pattern geometric transformation image processing on a plurality of blocks of pixels, a process of detecting the highest gradation in the plurality of pixels in the block, and a step of the gradation detected in the detection process. ,
A process of rearranging data corresponding to the scanning in the block, a process of generating a scanning signal in the block based on the rearranged data, and a process of winding around a plate cylinder based on the scanning signal in the block. A plate making method by scanning the inside of the block of the pattern to be formed on the formed plate.