JPH09141817A - Plate making apparatus - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a plate making apparatus that corrects the deviation of the plate making concave portion and improves the quality of the plate sheet of the plate making. A plate making apparatus includes a rotary encoder 8 that generates an encoder clock 100 in synchronization with rotation of a plate sheet 2, a dot before delay start signal (plate making timing signal) 104, and a line before delay start position from the encoder clock 100. A plate-making position detection circuit 11 that generates a signal 102, a correction amount calculation circuit 14 that sets a correction amount that corrects the dot start position of each line, and a pre-delay dot start signal (plate-making timing signal) 104 based on the correction amount. The digital delay circuit 12 delays the pre-delay line start position signal 102 and outputs the post-delay platemaking timing signal 108 and the post-delay line start position signal 106.

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 suitable for use in electronic gravure printing, for example.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No.
There was an electronic gravure printing system for performing intaglio printing, as described in Japanese Patent No. 38. This electronic gravure printing system uses a sheet-shaped plate material (hereinafter, referred to as “plate sheet”) having a thickness of about 200 μm and formed of a thermoplastic resin such as polyethylene resin.

In an electronic gravure printing system, first, in a plate making process by a plate making apparatus, a laser beam of a semiconductor laser is reciprocated in the axial direction of the plate cylinder while the plate sheet is wound around the outer periphery of the plate cylinder and rotated at high speed. By engraving with the image data, plate image data is formed on the surface of the plate sheet due to unevenness such as photographs.

Next, in the printing process by the printing device, the plate sheet made in the previous plate making process is rewound around the outer periphery of the plate cylinder of the printing device. Then, while rotating the plate cylinder at a high speed, ink is applied to the image data due to the unevenness of the plate sheet by an ink roll, and at the same time, the recording paper, which is the material to be printed, is pressed against the surface of the plate sheet by a driven impression cylinder. An image such as a photograph is printed at high speed on the surface of the recording paper as it is fed.

At this time, in the case of color printing, in addition to the three primary colors of cyan (C), magenta (M) and yellow (Y), black (K) and the like are used for multi-colored overprinting. I do.

Further, according to the electronic gravure printing system, image data due to unevenness can be engraved on the surface of the plate sheet with high accuracy with a submicron order by a laser beam emitted from a semiconductor laser. It is possible to print with extremely high accuracy.

FIG. 14 is a block diagram of a conventional intaglio plate making apparatus previously filed by the applicant of the present invention. First, the structure of this intaglio plate making apparatus will be described. This intaglio plate making apparatus includes a plate cylinder 140, a plate cylinder rotation motor 142, a plate sheet 141, a semiconductor laser 144, and a ball screw 1.
43, a laser block moving motor 145, a rotary encoder 148, and a plate making position detection circuit 145.
The CPU 146, the data RAM 147, the image data register 148, the gamma conversion circuit 149, and the laser driver 150.

Next, the connection relationship will be described. The large cylinder plate cylinder 140 and the small cylinder ball screw 143 are rotatably supported horizontally and in parallel by a support member (not shown) on a base (not shown). A plate cylinder rotating motor 142 is provided at one end of the plate cylinder 140 so as to be able to transmit a rotational force to the plate cylinder 140. A rotary encoder 148 is provided at the other end of the plate cylinder 140 so as to output a rotation signal of the plate cylinder 140. A laser block moving motor 145 is provided at one end of the ball screw 143 so as to be able to transmit a rotational force to the ball screw 143. Ball screw 143
A semiconductor laser 144 is provided on the top of the semiconductor laser 144 so as to be movable in the laser block moving direction 147 by the rotation of the ball screw 143.

The rotary encoder 148 is connected to the plate making position detection circuit 145. Plate making position detection circuit 14
5 is connected to the CPU 146. Further, the plate making position detection circuit 145 is connected to the image data register 148. The data RAM 147 is connected to the CPU 146. The CPU 146 is connected to the image data register 148. The image data register 148 is connected to the gamma conversion circuit 149. The gamma conversion circuit 149 is connected to the laser driver 150. The laser driver 150 is connected to the semiconductor laser 144.

The operation of the conventional intaglio plate making apparatus having the above structure will be described below. A plate sheet 1 made of a thermoplastic resin such as polyethylene resin is provided on the outer peripheral surface of the plate cylinder 140.
41 is wrapped around. Plate cylinder rotating motor 142
When the plate cylinder 140 is rotationally driven by, the plate sheet 141 wound around the outer peripheral surface of the plate cylinder 140 rotates.

When the plate cylinder 140 is driven to rotate, the rotary encoder 148 outputs a reference pulse a and an absolute position signal b as rotation signals. The reference pulse a is “100,000” pulses per one rotation of the plate cylinder 140. The absolute position signal b is 1 for each rotation of the plate cylinder 140.
Individual pulses.

The reference pulse a and the absolute position signal b are supplied to the plate making position detection circuit 145. Plate making position detection circuit 1
45 generates a plate making timing signal q and a reference position signal c based on the reference pulse a and the absolute position signal b. The plate-making timing signal q is generated by counting up the reference pulse a. The reference position signal c is a signal for using a predetermined absolute position as the reference position of the plate cylinder, and is generated from the absolute position signal b.

The plate-making timing signal q is supplied to the CPU 146 and the image data register 148. Reference position signal c
Is used as a rotational position signal of the plate cylinder 140 in the CPU 146. C at the timing of plate-making timing signal q
Image data is read from the data RAM 147 by an instruction from the PU 146. The image data is written in the image data register 148 by the instruction of the CPU 146 at the timing of the plate-making timing signal q.

Then, the image data is supplied from the image data register 148 to the gamma conversion circuit 149 at the timing of the next plate-making timing signal q. Gamma conversion circuit 14
Reference numeral 9 corrects the deviation between the image density characteristic and the print density characteristic. The gamma-converted plate-making data is the laser driver 1
50. The laser driver 150 generates a laser drive signal based on the plate making data. The laser drive signal is supplied to the semiconductor laser 144. The semiconductor laser 144 is driven according to the contrast of the image. The density of the image can be expressed by changing the size of the plate-making depression 151 formed by the laser or changing the depth of the plate-making depression 151.

With the plate sheet 141 rotated at a constant speed,
By irradiating the surface of the plate sheet 141 with laser light from the semiconductor laser 144, a plate-making recess corresponding to an image is formed. By performing such laser irradiation over the entire surface of the plate sheet 141 in synchronization with the image,
The plate sheet 141 is formed with unevenness including shades corresponding to an image. The density of the image is represented by whether the size of the plate-making recess formed by laser beam irradiation is changed or the depth of the recess is changed.

FIG. 15 shows the relationship between a conventional plate making pattern and a plate making timing signal. On the plate sheet 141, the laser head moving direction 146 corresponds to the plate cylinder rotating direction, and the laser block moving direction 147 corresponds to the plate cylinder axial direction.

The time when the reference position signal c formed based on the absolute position signal b is obtained is the plate making start reference point for the plate sheet 141. The position advanced by a predetermined number of pulses from this is the plate-making start position 154 in the even-numbered columns. The plate making interval W is a constant interval. The plate-making depressions 153 in the odd-numbered rows are shifted from the plate-making depressions 152 in the even-numbered rows by a half of the plate-making distance W, and the plate-making depressions 156 are horizontally fed.

The reason why the odd-numbered plate-making depressions 153 are shifted from the plate-making depressions 152 in the even-numbered row by ½ of the plate-making interval W is to improve moire. Further, as another measure for improving moire, the plate making pattern is a parallelogram in this example. FIG. 16 is a diagram showing a plate making pattern. In FIG. 16, one plate making recess 160 is formed from the plate making start position 162 of the plate making center 161 to the plate making section 16
Plated over 3 times. In this case, the plate making is performed so that the plate making pattern becomes a parallelogram when viewed from the plane.

[0019]

However, in such a conventional plate making apparatus, since the entire apparatus is large, it is difficult to make the plate cylinder 140 and the ball screw 143 parallel to each other. As a result, there is a problem in that the maximum deviation of about 50 microns occurs from the start position to the end position of the plate making concave portion on the plate sheet in the laser block moving direction, and due to this deviation, the quality of the plate sheet for plate making deteriorates.

The present invention has been made in view of the above points, and an object thereof is to provide a plate making apparatus which corrects the deviation of the plate making concave portion and improves the quality of the plate sheet of the plate making.

[0021]

The plate making apparatus of the present invention comprises:
A dot forming means for forming dots with unevenness corresponding to plate-making data while moving in a sub-scanning direction orthogonal to the main scanning direction on a plate sheet rotating in the main scanning direction, and a predetermined number of pulses in synchronization with rotation of the plate sheet. A rotary encoder for generating an encoder clock consisting of, a plate-making timing signal for starting the formation of each dot on the plate sheet from the encoder clock, and a plate-making position detecting means for generating a line start position signal for each line in the main scanning direction, A correction amount setting means for setting a correction amount for correcting the dot start position of each line, and a plate making timing signal and a line start position signal are delayed based on the correction amount, and a delayed plate making timing signal and a delayed line start position signal are output. And a delay means for performing delay based on the delay plate-making timing signal and the delay line start position signal. Performs No. process, in which the cut start position of each plate making line based on the correction amount so that the variable.

Further, the plate making apparatus of another invention comprises a dot forming means for forming dots with unevenness corresponding to the plate making data on the plate sheet rotating in the main scanning direction while moving in the sub scanning direction orthogonal to the main scanning direction. , A rotary encoder that generates an encoder clock consisting of a predetermined number of pulses in synchronization with the rotation of the plate sheet, a plate-making timing signal that starts the formation of each dot on the plate sheet from the encoder clock, and each line in the main scanning direction. Plate making position detection means for generating a line start position signal, correction amount setting means for setting a correction amount for stepwise correcting the dot start position for each of a plurality of lines, and signal processing is performed based on the encoder clock. The plate making start position for each of the plurality of plate making lines is made variable in a plurality of steps based on the correction amount.

The plate making apparatus of the present invention has the following functions. A plate sheet is wrapped around the outer peripheral surface of the plate cylinder. When the plate cylinder is driven to rotate, the plate sheet wound around the outer peripheral surface of the plate cylinder rotates. When the plate cylinder is driven to rotate, the rotary encoder outputs an encoder clock as a rotation signal.

The encoder clock is supplied to the plate making position detecting means. The plate-making position detecting means is a line reference signal based on the encoder Z-phase signal and the encoder pulse signal,
A pre-delay line start position signal, a pre-delay dot start signal, and a pre-delay line end signal are generated.

The line reference signal is supplied to the CPU. The line reference signal is used as a rotational position signal of the plate cylinder in the CPU. The pre-delay line start position signal, the pre-delay line end signal and the pre-delay dot start signal are supplied to the delay means. The correction amount calculated by the correction amount setting means is the CPU
Supplied to The CPU sets the digital delay amount based on the correction amount. The set digital delay amount is supplied to the delay means. Here, the correction amount is calculated for each line, and this digital delay amount is set for each line.
A gamma conversion clock is supplied to the delay means as a clock for performing digital delay. The gamma conversion clock is supplied from the D / A conversion circuit.

A pre-delay line start position signal, a pre-delay line end signal and a pre-delay dot start signal are supplied as input signals to the input terminals of the delay means. The delay amount selection terminal sets the delay amount based on the set digital delay amount. The gamma conversion clock is supplied to the clock terminal.

The delay means delays the input signal by a delay amount corresponding to the gamma conversion clock and outputs the output signal from the output terminal. The output signals are a delayed line start position signal, a delayed line end signal and a delayed plate making timing signal (delayed dot start signal). The post-delay line start position signal falls after a delay time from the fall of the pre-delay line start position signal. The post-delay platemaking timing signal (post-delay dot start signal) falls after a delay time from the fall of the pre-delay dot start signal. The delayed dot start signal is the first dot, the second dot, and the third dot.
The second dot, the signal up to the final Mth dot are included, and each dot is delayed by the delay time. The post-delay line end signal falls after a delay time from the fall of the pre-delay line end signal.

The delayed line start position signal and the delayed line end signal are supplied to the CPU. The delayed plate-making timing signal (delayed dot start signal) is supplied to the subsequent data processing circuit. The gamma conversion circuit in the data processing circuit gamma-converts the conversion upper address and the conversion lower address based on the gamma conversion clock. Here, the gamma conversion changes the tone density of a portion in one dot of the plate-making data. The gradation density can be changed by changing the dot length and the dot depth.

The gamma conversion circuit corrects the deviation between the density characteristic of the image of the platemaking data and the density characteristic of printing. The gamma conversion circuit gamma-converts the plate-making data using a look-up table in which the conversion data is stored in a table in advance. The converted data is output as a laser drive signal.

The laser drive signal is supplied to the D / A converter. The D / A converter converts a laser drive signal of a digital signal into a laser drive signal of an analog signal. The laser drive signal is supplied to the plate-making laser driver. The plate-making laser driver generates a laser drive current based on the laser drive signal. The laser drive current is supplied to the dot forming means. The dot forming means irradiates the plate sheet with laser light to form a plate-making depression on the plate sheet.

The post-delay plate making section of each dot starts from the trailing edge of the post-delay plate making timing signal (post-delay dot start signal). The delay time of the plate-making section of each dot after the delay is smaller than the delay time of the plate-making section of each dot before the delay. Therefore, a fine start position can be set.

The dot arrangement pattern includes several encoder clocks from the start line to the end line in the sub-scanning direction, and from the main scan start position of the start line in the main scan direction to the main scan start position of the end line. When the misalignment occurs, the dots in each line in the sub-scanning direction are arranged so as to be sequentially deviated in the main scanning direction. The dot correction amount for each line at this time is calculated by the correction amount setting means of the CPU based on the number of lines and the shift amount.

In this way, the start position signal of each dot is digitally delayed by the gamma conversion clock. Thereafter, the post-stage processing proceeds with reference to the digitally delayed delayed dot start signal, and as a result, the digital delay delays the laser drive current as it is to perform plate making, so that the entire line can be shifted. The minimum unit for shifting is determined by the frequency f of the gamma conversion clock and the rotation speed N of the plate cylinder, and the gamma clock width can be set at intervals of a predetermined number of times the encoder clock width.

At this time, the main scanning start position of each line is
Since the setting is made finer than the cycle of the encoder clock, the quality of plate making is improved, and thus the quality of printing can be improved.

Further, according to the plate making apparatus of another invention, the following effects are obtained. In synchronization with the encoder clock, a line reference signal, a line start position signal, a plate making timing signal (dot start signal), and a line end signal are generated by the plate making position detecting means.

The dot start signal is supplied to the data transfer control circuit and the gamma conversion section, which are the data processing circuits in the subsequent stage. The data transfer control circuit generates a preload signal for writing the next plate-making data from the image memory to the preload register of the gamma conversion unit by using the dot start signal as a trigger. The gamma conversion unit transfers the value of the preload register to the conversion upper address register by using the dot start signal as a trigger. In the gamma conversion circuit, the signal synchronized with the encoder clock until then is resampled using the high-speed gamma conversion clock, and gamma conversion is performed.

Since the dot start signal is synchronized with the encoder clock, the minimum unit of the pulse width of the encoder clock is the line start position and dot interval.
In the dot arrangement pattern, a shift of several encoder clocks occurs between the start line in the sub-scanning direction and the end line, and between the main scanning start position of the start line in the main scanning direction and the main scanning start position of the end line. At this time, the dots on each line in the sub-scanning direction are arranged so as to be divided into a plurality of steps from the start line to the end line in the main scanning direction, and are provided with stepwise boundaries. The amount of dot correction at each stage at this time is calculated by the correction amount setting means of the CPU based on the number of lines and the amount of deviation.

As described above, when there is a shift of several clocks, the line is divided into several lines in the sub-scanning direction to correct the dot position in the main-scanning direction in a plurality of steps, so that simple dot correction can be performed. it can.

[0039]

1 is a block diagram showing the configuration of an intaglio plate making apparatus of this embodiment. First, the configuration of the plate making apparatus of this embodiment will be described. This plate making apparatus includes a plate cylinder 1 and
Plate cylinder rotating motor 3, plate sheet 2, high-power semiconductor laser 5, ball screw 4, laser block moving motor 6, rotary encoder 8, plate making position detection circuit 11, and digital delay circuit 12. , CPU1
3, a data transfer control circuit 15, an image memory 16,
It has a gamma conversion section 17, a D / A conversion section 22, and a plate-making laser driver 23.

Here, the CPU 13 uses the correction amount calculation circuit 14
And the gamma conversion unit 17 has a preload register 18
The conversion upper address register 19, the conversion lower address generation unit 21, and the gamma conversion circuit 20. Further, the high-power semiconductor laser 5 is a dot forming means, the correction amount calculation circuit 14 is a correction amount setting means, and the plate making position detection circuit 11 is provided.
Is a plate making position detecting means, and the digital delay circuit 12 is a delay means.

Next, the connection relationship will be described. The large cylinder plate cylinder 1 and the small cylinder ball screw 4 are rotatably supported horizontally and in parallel by a support member (not shown) on a base (not shown). A plate cylinder rotating motor 3 is provided at one end of the plate cylinder 1 so as to transmit a rotational force to the plate cylinder 1.
A rotary encoder 8 is provided at the other end of the plate cylinder 1 so as to output a rotation signal of the plate cylinder 1. A laser block moving motor 6 is provided at one end of the ball screw 4 so as to transmit a rotational force to the ball screw 4. A semiconductor laser 5 is provided on the ball screw 4 so as to be movable in the laser block moving direction 10 by the rotation of the ball screw 4.

The rotary encoder 8 is connected to the plate making position detection circuit 11. The plate-making position detection circuit 11 is CP
It is connected to U13. Further, the plate making position detection circuit 11
Is connected to the digital delay circuit 12. further,
The digital delay circuit 12 is connected to the CPU 13. The correction amount calculation circuit 14 is provided inside the CPU 13. The digital delay circuit 12 is connected to the data transfer control circuit 15.

The data transfer control circuit 15 includes an image memory 16
Is connected to The image memory 16 is connected to the D input terminal of the preload register 18. The Q output terminal of the preload register 18 is the conversion upper address register 19
It is connected to the D input terminal of. The Q output terminal of the conversion upper address register 19 is connected to the gamma conversion circuit 20. The conversion lower address generator 21 is connected to the gamma conversion circuit 20.

The gamma conversion circuit 20 is connected to the D / A conversion section 22. The D / A converter 22 is connected to the plate-making laser driver 23. Plate-making laser driver 23
Is connected to a high power semiconductor laser 5. here,
The clock output terminal of the D / A converter 22 is connected to the clock terminal of the digital delay circuit 12. Also, D /
The clock output terminal of the A conversion unit 22 is connected to the clock terminal of the conversion lower address generation unit 21. Furthermore, D
The clock output terminal of the / A conversion unit 22 is the gamma conversion circuit 2
It is connected to the 0 clock terminal.

The delayed preload output terminal of the data transfer control circuit 15 is connected to the clock terminal CK of the preload register 18. The digital delay circuit 12 is connected to the clock terminal CK of the conversion upper address register 19. The digital delay circuit 12 is connected to the conversion lower address generator 21. Further, FIG. 4 shows an internal configuration block diagram of the plate making position detection circuit of this embodiment. First, the configuration of this plate making position detection circuit will be described. This plate making position detection circuit includes a plate cylinder rotation position counter 40, a comparator 41, an operation control circuit 42, and a plate making interval detection circuit 43.
And a plate making dot number counting circuit 44.

Next, the connection relation of this plate making position detection circuit will be shown. In the rotary encoder 8, the encoder Z-phase signal 100a and the encoder pulse signal 100b of the encoder clock 100 are used as the plate cylinder rotation position counter 4
It is connected to the plate cylinder rotation position counter 40 so as to be supplied to 0. The encoder Z-phase signal 100a is an absolute position signal output every time the rotary encoder 8 makes one rotation. Plate cylinder rotation position counter 40 Comparator 41
Connected to The comparator 41 is connected to the plate making interval detection circuit 43 so that the pre-delay line start position signal 102 of the comparator 41 becomes the operation start trigger signal 49.

Further, the rotary encoder 8 uses the encoder pulse signal 10 of the encoder clock 100.
0b is supplied to the operation control circuit 42 so that it is connected to the operation control circuit 42. The operation control circuit 42 is connected to the plate making interval detection circuit 43. The plate-making interval detection circuit 43 is connected to the plate-making dot number counting circuit 44. The plate-making dot number counting circuit 44 is connected to the operation control circuit 42.

FIG. 6 is a diagram showing the configuration of the digital delay circuit of this embodiment. This digital delay circuit is one IC, and has an input terminal D, an output terminal Q, and
It has a delay amount selection terminal 60 for "S ₀ " to "S ₅ ", and a clock terminal CK. The gamma conversion circuit 20 is composed of a RAM having a look-up table that stores gamma conversion data.

The operation of the plate making apparatus of this embodiment having the above-described structure will be described below. FIG. 2 shows a timing chart of the start operation of the plate making line of this embodiment. A plate sheet 2 made of a thermoplastic resin such as polyethylene resin is wound around the outer peripheral surface of the plate cylinder 1. When the plate cylinder 1 is rotated by the plate cylinder rotation motor 3, the plate sheet 2 wound around the outer peripheral surface of the plate cylinder 1 rotates.

When the plate cylinder 1 is driven to rotate, the rotary encoder 8 outputs a rotation signal as an encoder clock 100.
Is output. In the embodiment, the rotation speed of the plate cylinder 1 is 5 [rp
s]. As shown in FIG. 2A, the distance 24 on the plate cylinder corresponding to the period of the encoder clock 100 is 5.3.
[Μm], which corresponds to 2 [μsec], and the encoder clock 100 is a pulse having a frequency of 500 [KHz].

The encoder clock 100 is supplied to the plate making position detection circuit 11. The plate-making position detection circuit 11 includes an encoder Z-phase signal 100a and an encoder pulse signal 10
Based on 0b, the line reference signal 101 shown in FIG. 2B, the pre-delay line start position signal 102 shown in FIG. 2C, the pre-delay dot start signal 104 shown in FIG. 2D, and the pre-delay line end signal 103 shown in FIG. 2E are generated. The before-delay dot start signal 104 includes signals up to the first dot 104a, the second dot 104b, the third dot 104c, and the final Mth dot 104d.

The operation of the plate making position detecting circuit will be briefly described with reference to the timing chart showing the operation of the plate making position detecting circuit of the present embodiment shown in FIG. In FIG. 5, the plate cylinder 1 rotates,
The start position of plate making is 10 of the encoder pulse signal 100b.
An example in which the number of pulses, the plate making interval is 5 pulses, and the number of plate making is 10 is shown. Encoder Z-phase signal 100 shown in FIG. 5A
a has a width of several pulses of the encoder pulse signal 100b shown in FIG. 5B. This encoder Z-phase signal 100a
The plate cylinder rotation position counter 40 is reset to "0" by the first one pulse width of. The plate cylinder rotation position counter 40 has a value of 100 from “0” to “99,999” shown in FIG. 5C.
The output value 45 of 000 plate cylinder counters is output. The plate cylinder counter output value 45 is supplied to the comparator 41. The comparator 41 compares the plate cylinder counter output value 45 with a predetermined reference value, and when the plate cylinder counter output value 45 is "0", outputs the line reference signal 101 shown in FIG. Is “10”, the pre-delay line start position signal 102 shown in FIG. 5E is output.

Further, the encoder pulse signal 100b is
The synchronous operation clock 46 is supplied to the operation control circuit 42. The operation control circuit 42 outputs an operation start / stop control signal 47 based on the synchronous operation clock 46. The operation start / stop control signal 47 is supplied to the plate making interval detection circuit 43. The pre-delay line start position signal 102 is supplied to the plate making interval detection circuit 43 as an operation start trigger signal 49. Based on the operation start / stop control signal 47 and the operation start trigger signal 49, the plate making interval detection circuit 43 operates as shown in FIG.
The dot before-delay start signal 104 shown in is output. The before-delay dot start signal 104 is the plate making dot number counting circuit 4
4 is supplied. The plate-making dot number counting circuit 44 counts 10 dots of the pre-delay dot start signal 104 and
The pre-delay line end signal 103 shown in G is output. The pre-delay line end signal 103 is supplied to the operation control circuit 42 as the count value coincidence signal 48. The operation control circuit 42 exchanges a CPU control signal with the CPU 13.

The line reference signal 101 is supplied to the CPU 13. The line reference signal 101 is used by the CPU 13 as a rotational position signal of the plate cylinder. The pre-delay line start position signal 102, the pre-delay line end signal 103, and the pre-delay dot start signal 104 are supplied to the digital delay circuit 12. The correction amount calculated by the correction amount calculation circuit 14 is supplied to the CPU 13. The CPU 13 sets the digital delay amount setting 105 based on the correction amount. The set digital delay amount 105 is supplied to the digital delay circuit 12. Here, the correction amount is calculated for each line, and the digital delay amount 105 is set for each line. The gamma conversion clock 115 is supplied to the digital delay circuit 12 as a clock for performing digital delay. The gamma conversion clock 115 shown in FIG. 2F is a D / A described later.
It is supplied from the conversion circuit 22. Gamma conversion clock 11
Reference numeral 5 is a signal having a frequency of 20 [MHz].

FIG. 6 shows the digital delay circuit of this embodiment.
FIG. 3 is a diagram illustrating a configuration. Input to input terminal D in FIG.
Pre-delay line start position signal 102, delay as signal D0
Previous line end signal 103 and delayed before dot start signal 1
04 is supplied. The delay amount selection terminal 60 is set
The delay amount is set based on the digital delay amount 105.
You. The gamma conversion clock 115 is applied to the clock terminal CK.
Supplied. In this embodiment, the gamma conversion clock is set to 20.
 [MHz], 100,000 encoder pulses, version
Since the body rotation speed is 5 [rps], the encoder
Clock width = 1 / (100,000 × 5) = 2 [μse
c], gamma clock width = 1 / (20 × 10⁶) = 50
 [nsec] is set, and the encoder clock is set with the gamma clock width.
The lock width can be divided into 40. Therefore, the amount of digital delay
Must be set to 1 to 39.
On the other hand, the digital operation is 2ⁿBecause it is convenient to be
2⁶= 64. Then, it is larger than the delay amount in this example.
It can support up to 65 divisions. 2⁶= 64, the delay amount
The setting uses 6 bits and the delay amount = 2 as shown in FIG.
⁰× S₀+2¹× S₁+2^Two× S_Two+2^Three× S_Three+2^Four
× S_Four+2^Five× S_FiveBecomes

The digital delay circuit 12 receives the input signal D0.
The output signal Dn is output from the output terminal Q with a delay corresponding to the gamma conversion clock 115.
The output signal Dn is the delayed line start position signal 106 shown in FIG. 2G, the delayed line end signal 107 shown in FIG. 2I, and the delayed plate-making timing signal (delayed dot start signal) 108 shown in FIG. 2H. Here, as shown in FIG. 2G, the post-delay line start position signal 106 is 2. after the fall of the pre-delay line start position signal 102 shown in FIG. 2C.
It falls after a delay distance 25 of 65 [μm]. The post-delay platemaking timing signal (post-delay dot start signal) 108 shown in FIG. 2H is the pre-delay dot start signal 10 shown in FIG. 2D.
It falls after a delay distance 26 of 2.65 [μm] from the fall of 4. The post-delay dot start signal 108 has signals up to the first dot 108a, the second dot 108b, the third dot 108c, and the final Mth dot 108d, and each dot is 2.65 [μm]. Delay distance 2
Delay by 6. Post-delay line end signal 1 shown in FIG. 2I
07 falls after a delay distance 27 of 2.65 [μm] from the fall of the pre-delay line end signal 103 shown in FIG. 2E. The delay distances 25, 26 and 27 are 5.
It can be set up to 3/40 [μm]. The delay distance is set to 2.65 [μm] because the gamma conversion clock is 2
This is because it is delayed by 0 clock, and is 50 [nsec].
This is because x20 = 1 [μsec], which is half the encoder clock width.

Here, the pre-delay line start position signal 102 and the pre-delay line end signal 1 are used as the input signal D0.
Although only one digital delay circuit 12 is shown for explanation of the three signals of 03 and the pre-delayed dot start signal 104, three digital delay circuits 12 are provided for each of the three signals. Then, the delayed line start position signal 106, the delayed line end signal 107, and the delayed plate-making timing signal (post-delayed dot start signal) 108 are output as output signals Dn from the three digital delay circuits 12, respectively. In this way, the gamma conversion clock 115
To digitally delay the three signals.

The delayed line start position signal 106 and the delayed line end signal 107 are supplied to the CPU 13.
Platemaking timing signal after delay (dot start signal after delay) 1
08 is supplied to the data transfer control circuit 15. The data transfer control circuit 15 reads the read control signal 11 based on the delayed plate-making timing signal (delayed dot start signal) 108.
Generate 0 and a delayed preload signal 109. The read control signal 110 is supplied to the image memory 16. The read control signal 110 performs arbitration (arbitration) for writing and reading plate-making data in the image memory 16.

Plate making data is transferred to the image memory 16 from an external interface section (not shown). The plate-making data transferred from the interface unit is 500 kilobytes each. The image memory 16 has a storage capacity of 1 megabyte so that it can store plate-making data for ten or more lines. Here, the capacity of plate-making data corresponding to one image is 40 megabytes. The image memory 16 outputs the next plate-making data 111 for 1 byte and 1 dot.

The next plate-making data 111 is supplied to the preload register 18. Here, the delayed preload signal 109 shown in FIG. 2J is supplied to the preload register 18. The preload register 18 delays the preload signal 1
The next plate-making data 111 for 1 byte and 1 dot is loaded based on 09, and output at the next clock, and this is repeated. The preload register 18 functions as a buffer. As shown in FIG. 2J, the delayed preload signal 109
Is 300 to 800 from the trailing edge of the delayed plate-making timing signal (delayed dot start signal) 108 shown in FIG. 2H.
It will fall after a delay of [nsec].

The reason why the delayed preload signal 109 is delayed in this way is shown in FIG. 2K in the preload register 18 when the delayed plate-making timing signal (delayed dot start signal) 108 shown in FIG. 2H falls. Of the delayed values of the preload register 18, Data1 (Ad
This is for determining dress1). Therefore, after this determination, the delayed preload signal 109 falls and Data2 (Address2) is preloaded, and the next delayed preload signal 109 sequentially falls and D
ata3 (Address3) is preloaded. That is, the preload register 18 operates as if the plate-making data for the next plate-making is written before the delayed plate-making timing signal (delayed dot start signal) 108 shown in FIG. 2H falls.

Next, the next plate-making data 111 for 1 byte and 1 dot is supplied to the conversion upper address register 19. Here, the delayed plate-making timing signal (delayed dot start signal) 108 shown in FIG. 2H is supplied to the conversion upper address register 19. The post-delay platemaking timing signal (post-delay dot start signal) 1
Based on 08, the next plate-making data 111 for 1 byte and 1 dot is loaded, the conversion upper address is output at the next clock, and this is repeated. As shown in FIG. 2L, the post-conversion upper address register 19 post-delay value is the delayed plate-making timing signal (delayed dot start signal) 1 shown in FIG. 2H.
At the time of the fall of 08, the immediately preceding Data (Add
output), and Data1 (Address1)
Load and repeat this in sequence.

Next, the next plate-making data 111 for 1 byte and 1 dot is supplied to the gamma conversion circuit 20. The post-delay platemaking timing signal (post-delay dot start signal) 108 is supplied to the conversion lower address generation unit 21. The gamma conversion clock 115 is supplied to the conversion lower address generation unit 21 and the gamma conversion circuit 20. The conversion lower address generator 21 outputs the conversion lower address at the next clock based on the delayed plate-making timing signal (delayed dot start signal) 108 and the gamma conversion clock 115. The gamma conversion circuit 20 performs gamma conversion on the conversion upper address and the conversion lower address based on the gamma conversion clock 115. Here, the gamma conversion changes the tone density of a portion in one dot of the plate-making data. The gradation density can be changed by changing the dot length and the dot depth. Hereinafter, the operation will be described.

FIG. 8 is a diagram showing changes in the dot length direction in the gamma conversion operation of this embodiment. In FIG.
The plan view of the 255 gradation dots 80 is the maximum parallelogram, and the sectional view at the center has the maximum length 255 gradation dot length 81. A plan view of an n-gradation (halftone) dot 82 is a parallelogram with an intermediate size, and a cross-sectional view at the center is an intermediate-length n-gradation dot length 83.
There is no plan view of the 0 gradation dot, and the sectional view at the center is a plane.

FIG. 9 is a diagram showing changes in the dot depth direction in the gamma conversion operation of this embodiment. In FIG. 9, the cross-sectional view at the center of the dot 90 is a plane when the depth level value is “0”, and the laser power [W]
Is "0". When the depth level value is "1", the depth 91 is a relatively shallow depth level value "1", and the laser power [W] is "0.5". When the depth level value is "2", the depth 92 of the intermediate depth level value "2"
And the laser power [W] is "1". When the depth level value is "3", the depth 93 is a relatively deep depth level value "3", and the laser power [W] is "1.5".

In this way, the gamma conversion circuit 20 corrects the deviation between the image density characteristic of the platemaking data and the print density characteristic. The gamma conversion circuit 20 gamma-converts the plate-making data according to a look-up table in which conversion data is stored in a table in advance. The converted data is output as the laser drive signal 112.

The laser drive signal 112 is supplied to the D / A converter 22. The D / A converter 22 converts the digital laser drive signal 112 into an analog laser drive signal 113. The laser drive signal 113 is supplied to the plate-making laser driver 23. The plate-making laser driver 23 generates a laser drive current 114 based on the laser drive signal 113. The laser drive current 114 is supplied to the high power semiconductor laser 5. The high-power semiconductor laser 5 irradiates the plate sheet 2 with a laser beam to form a plate-making recess 7 on the plate sheet 2.
Is formed.

As shown in FIG. 2M, the plate-making section of each post-delay dot starts from the trailing edge of the post-delay plate-making timing signal (post-delay dot start signal) 108 shown in FIG. 2H. Since the plate making section of each dot before delay shown in FIG. 2N was started from the trailing edge of the dot before start signal 104 before delay, the delay distance 29 indicating the difference is smaller than the encoder clock interval. Therefore, a fine start position can be set.

FIG. 3 shows an enlarged view of the dot arrangement pattern according to this embodiment. In FIG. 3, the dots 34 are arranged from the start line “1” in the sub-scanning direction 32 to the end line “37”, from the main scan start position 36 of the start line in the main scan direction 33 to the main scan start position 35 of the end line. Up to the above, when the encoder clock 100 is deviated by four clocks, the dots in each line in the sub-scanning direction 32 are arranged so as to be sequentially deviated in the main scanning direction 33. At this time, the dot correction amount for each line is calculated by the correction amount calculation circuit 14 of the CPU 13 based on the number of lines and the amount of deviation.

In this way, the start position signal of each dot is digitally delayed by the gamma conversion clock 115. Thereafter, the delayed dot start signal 108 which is digitally delayed
As a result, the subsequent processing proceeds, and as a result, the digital delay delays the laser drive current 114 as it is to perform plate making, so that the entire line can be shifted. The minimum unit for shifting is determined by the frequency f of the gamma conversion clock 115 and the rotation speed N of the plate cylinder 1, and the gamma clock width 1 / f [sec] with respect to the encoder clock width 1 / (100,000 × N) [sec]. ] Interval can be set. In this example, f is 20 [MHz] and N is 5 [rp]
s] is 2 [μsec] without delay, whereas it can be divided into 40 with a delay time of 50 [nsec].

At this time, the main scanning start position of each line is
Since the distance 24 corresponding to the period of the encoder clock 100 shown in FIG. 2A is set to be smaller than 5.3 [μm], the quality of plate making is improved, and thus the quality of printing can be improved. .

In addition to the dot start signal, the line start position signal and the line end signal are digitally delayed by the same amount. This is because, for example, the CPU 13 performs the digital delay amount setting 105 for the next line in response to the line end signal, and is for preventing the occurrence of a shift before and after the processing timing. Further, the processing time required for the digital delay amount setting 105 is extremely short, and even if this processing is added, the CPU
The burden of 13 hardly increases. That is, there is almost no burden of changing the software.

Further, here, the resampling by the gamma conversion clock is accelerated, but since the same signal source is used, the sampling error is the same as the conventional one. Moreover, since the clock is distributed from the downstream side to the upstream side of the processing, the clock timing in the preceding stage does not advance the clock timing in the succeeding stage, so that a data shift error does not occur.

Here, the plate sheet 2 is provided for each color. In this example, two plate making devices are provided, C (cyan) and K (black) plate sheets are made by the first plate making device, and M (magenta) and Y (yellow) plate sheets are made by the second plate making device. Plate-making is done with a plate-making device. Here, the formation of dots for each color will be described. FIG. 10 is a diagram showing the inclinations of the dots of the respective colors and the distances between the centers in the present embodiment.
In FIG. 10, a C (cyan) dot has a parallelogram angle of 40 degrees that descends to the right, the arrangement between dots is C1, C2, and C3, and the distance between the centers is C3 and C1. Is d1, the space between C1 and C2 is d2, and the space between C2 and C3 is d3. Here, d1 and d3 have the same distance. The K (black) dots have a parallelogram angle of 40 degrees that descends to the right, and the positions between the dots are K1, K2, and K.
The distance between the centers is d4 between K1 and K2, d5 between K2 and K3, and d between K3 and K4.
6, d7 is between K4 and K1. Where d4 and d6
And d5 and d7 have the same distance.

An M (magenta) dot has a parallelogram angle of 40 degrees, which is a left downward slope, and the arrangement between dots is M.
1, M2, M3, and the distance between the centers is M3 and M
Between 1 is d8, between M1 and M2 is d9, and between M2 and M3 is d10. Here, d8 and d10 have the same distance. The Y (yellow) dots have a parallelogram angle of 40 degrees to the left, and the arrangement between the dots is Y1, Y.
2, Y3, Y4, and the distance between the centers is Y1 and Y
2 is d11, Y2 and Y3 are d12, Y3 and Y4
The distance between them is d13, and the distance between Y4 and Y1 is d14. Here, d11 and d13 and d12 and d14 have the same distance.

As described above, since the inclinations of the dots of the respective colors and the distances between the centers are different from each other, moire does not occur even when the plate sheets of the respective colors are superposed at the printing stage and the dots of the respective colors are superposed. Thus, according to the above example, in the intaglio plate making apparatus, by digitally delaying the timing of the main scanning start position synchronized with the encoder clock with the high-speed gamma conversion clock,
It is possible to control the plate making with timing finer than the encoder clock width. As a result, high-quality printing can be performed with accurate position accuracy, and high-quality printed matter can be obtained.

Further, according to the above example, the plate making position detecting device 1
1 before delay line start position signal 102, before delay dot start signal 104, before delay line end signal 10
3 is digitally delayed by a digital delay circuit corresponding to a shift register. As a result, all the subsequent processing such as plate-making data transfer, gamma conversion, light output laser emission, etc. can be digitally delayed, and the entire one line can be shifted more finely than the encoder pulse unit.

Further, according to the above example, since the gamma conversion clock used in the subsequent stage is used as the shift clock used in the digital delay circuit 12, the sampling timing error can be suppressed. Further, since the gamma conversion clock has a speed capable of counting several hundred dots between dots, it counts several tens of encoder pulses, that is, the main scanning of each line is fine with a unit of several tenths of the encoder pulse. You can set the starting position.

According to the above example, the CPU 13 processes the digital delay amount of the delayed line start position signal 106, the delayed dot start signal 108, the delayed line end signal 107, etc. of each line by the digital delay circuit 12. However, the processing time required for this is extremely short and therefore does not burden the CPU 13. That is, there is almost no burden required for changing the software.

In the above example, only the example in which the plate-making start position of each plate-making line is delayed based on the correction amount is shown, but the plate-making start position of each plate-making line is advanced based on the correction amount according to the dot misalignment mode. You may do it. In this case, the line reference signal 1 is previously set in units of the pulse width of the encoder clock.
01, line start position signal 102, dot start signal 10
4. Advance the line end signal 103 and then delay it by using the digital delay circuit 12 so that the overall processing apparently proceeds.

In the above example, the digital delay circuit 12
Although only the example in which the plate making start position of each plate making line is delayed based on the delay correction amount using
Instead of 2, a delay circuit that can set the same delay amount may be used.

Next, another embodiment will be described. FIG.
FIG. 1 is a block diagram showing a configuration of a plate making apparatus according to another embodiment. The configuration of the plate making apparatus of this example is different from the previous example shown in FIG. 1 in that the digital delay circuit 12 is not provided. Other configurations are similar to those of the previous example shown in FIG. Further, the operation of this example is different from the previous example shown in FIG. 1 in that the correction amount calculation circuit 14 calculates the correction amount in units of a plurality of lines, and the dots are formed stepwise in a unit of a plurality of lines in the main scanning direction. The point is to shift.

The operation will be briefly described below. As shown in FIG. 12A, the distance 120 on the plate cylinder corresponding to the cycle of the encoder clock 100 is 5.3 [μm], and the encoder clock 100 is a pulse having a frequency of 500 [KHz]. In synchronization with the encoder clock 100, the line reference signal 101 shown in FIG. 12A, the line start position signal 102 shown in FIG. 12C, the plate making timing signal (dot start signal) 116 shown in FIG. 12D, and the line end signal 103 shown in FIG. 12E. Is generated by the plate making position detection circuit 11. The dot start signal 116 is the first dot 11
6a, second dot 116b, third dot 116
It has a c, Mth dot 116d. The delay time 122 of the line end signal 103 is the same as in the previous embodiment.

The dot start signal 116 is supplied to the data transfer control circuit 15 and the gamma conversion section 17. The data transfer control circuit 15 uses the dot start signal 116 as a trigger to generate a preload signal 117 for writing the next plate-making data 111 from the image memory 16 to the preload register 18 of the gamma conversion unit 17. The preload signal 117 is shown in FIG.
Shown on 2F. The gamma converter 17 uses the dot start signal 116.
Is used as a trigger to transfer the value of the preload register 18 to the conversion upper address register 19. Gamma conversion circuit 2
At 0, the signal synchronized with the encoder clock until then is resampled using the high-speed gamma conversion clock 115 of 20 [MHz], and gamma conversion is performed.

Since the dot start signal 116 is synchronized with the encoder clock 100, the minimum unit of the line start position and the dot interval is 5.3 [μm]. Therefore, the plate making section of each dot shown in FIG. 12J starts from the dot start signal, and the line start delay distance 124 shown in FIG. 12K becomes [5.3 μm]. FIG. 13 shows an enlarged view of the dot arrangement pattern according to this example. In FIG. 13, the dots 134 are arranged in the main scanning direction 1 from the start line “1” to the end line “37” in the sub scanning direction 132.
When a deviation of 4 encoder clocks 100 occurs between the main scanning start position 136 of the start line 33 and the main scanning start position 135 of the end line, the dots in each line in the sub-scanning direction 132 are main-scanned. Direction 1
33, start lines “1” to “5”, “6” to “14”,
"15" ~ "23", "24" ~ "32", "33" ~
The line up to the end line "37" is divided into four, and the lines are shifted in five steps so that a step-like boundary 137 is provided. At this time, the dot correction amount for each step is calculated by the correction amount calculation circuit 14 of the CPU 13 based on the number of lines and the amount of deviation.

As described above, according to the above example, when there is a shift of 4 clocks, the line is divided into 4 in the sub-scanning direction in units of the pulse width of the encoder clock, and the dot position in the main scanning direction is divided into 5 steps. Is corrected, so that simple dot correction can be performed.

In the above example, when there is a shift of 4 clocks, the line is divided into four in the sub-scanning direction and the line is divided in the sub-scanning direction 132.
The start line "1" to the end line "37" are shifted in five steps. For example, if all lines are 5000 lines and the start position of each dot is shifted by 9 clocks in the main scanning direction, then It is possible to divide each line into 9 parts and shift them in 10 steps.

[0088]

According to the plate making apparatus of the present invention, dot forming means for forming dots with unevenness corresponding to plate making data while moving in a sub scanning direction orthogonal to the main scanning direction on a plate sheet rotating in the main scanning direction, A rotary encoder that generates an encoder clock consisting of a specified number of pulses in synchronization with the rotation of the plate sheet, a plate-making timing signal that starts the formation of dots on the plate sheet from the encoder clock, and a line of each line in the main scanning direction. A plate-making position detection unit that generates a start position signal, a correction amount setting unit that sets a correction amount that corrects the dot start position of each line, and a plate-making timing signal and a line start position signal are delayed based on the correction amount, A delay plate-making timing signal and a delay means for outputting a delay line start position signal are provided. The signal processing is performed based on the delay line start position signal and the delay line start position signal, and the plate making start position of each plate making line is made variable based on the correction amount.Therefore, it is possible to control the plate making at a timing finer than the encoder clock width. it can. As a result, high-quality printing can be performed with accurate position accuracy, and high-quality printed matter can be obtained. Further, according to the present invention, the line start position signal and the plate making timing signal (dot start signal) output from the plate making position detecting means are digitally delayed by the delay means. It is possible to digitally delay all processing and each processing such as light output laser emission by the dot forming means.
The entire line can be shifted more finely than the encoder pulse unit. Further, according to the present invention, the digital delay amount of the delayed line start position signal, the delayed dot start signal, etc. by the delay means is set before the processing of each line is started by the delay amount setting means, Since the processing time required for this is extremely short, it does not burden the CPU. That is, the load required for changing the software can be reduced.

Further, in the plate making apparatus of the present invention, in the above description, the delay means delays by using the clock for sampling the plate making data to be supplied to the dot forming means. The plate making can be controlled at timing. As a result, high-quality printing can be performed with accurate position accuracy, and high-quality printed matter can be obtained.

In the plate making apparatus of the present invention, the gamma conversion is performed on the basis of the delayed plate making timing signal, and the delay means delays by using the clock for gamma conversion. Since the gamma conversion clock used in the subsequent stage is used as the shift clock, the sampling timing error can be suppressed. Further, since the gamma conversion clock has a speed capable of counting several hundred dots between dots, it counts several tens of encoder pulses, that is, the main scanning of each line is fine with a unit of several tenths of the encoder pulse. You can set the starting position.

Further, the plate making apparatus according to the present invention comprises dot forming means for forming dots with unevenness corresponding to the plate making data while moving in the sub scanning direction orthogonal to the main scanning direction on the plate sheet rotating in the main scanning direction, A rotary encoder that generates an encoder clock consisting of a specified number of pulses in synchronization with the rotation of the plate sheet, a plate-making timing signal that starts the formation of dots on the plate sheet from the encoder clock, and a line of each line in the main scanning direction. A plate making position detecting means for generating a start position signal, a correction amount setting means for setting a correction amount for stepwise correcting the dot start position for each of a plurality of lines in the sub-scanning direction, and performing signal processing based on an encoder clock, The plate-making start position for each plate-making line is made variable in multiple steps based on the correction amount. Dividing the line in the main scanning direction to correct the position of the dot in the pulse width unit of the encoder clock, it can be corrected with a simple dot.

Further, in the plate making apparatus of the present invention, in the above description, the correction amount is set in a plurality of stages based on the number of encoder clocks with respect to the deviation of the dot start position in the sub-scanning direction. If there is, the line is divided into n in the sub-scanning direction and the position of the dot is corrected in the main scanning direction in n + 1 steps in units of the pulse width of the encoder clock, so that simple dot correction can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a plate making apparatus according to an embodiment of the present invention.

FIG. 2 is a timing chart showing the starting operation of the plate making line of the plate making apparatus according to the embodiment of the present invention.

FIG. 3 is an enlarged view showing a dot arrangement pattern of the plate making apparatus according to the embodiment of the present invention.

FIG. 4 is a block diagram showing an internal configuration of a plate making position detection circuit of the plate making apparatus according to the embodiment of the present invention.

FIG. 5 is a timing chart showing the operation of the plate making position detection circuit of the plate making apparatus according to the embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a digital delay circuit of the plate making apparatus according to an embodiment of the present invention.

FIG. 7 is a diagram showing an operation of the digital delay circuit of the plate making apparatus according to the embodiment of the present invention.

FIG. 8 is a diagram showing changes in the dot length direction in the gamma conversion operation of the plate making apparatus according to the embodiment of the present invention.

FIG. 9 is a diagram showing changes in the depth direction of dots in the gamma conversion operation of the plate making apparatus according to the embodiment of the present invention.

FIG. 10 is a diagram showing the inclination of dots of each color and the distance between the centers of the plate making apparatus according to the embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration of a plate making apparatus according to another embodiment of the present invention.

FIG. 12 is a timing chart showing the starting operation of the plate making line of the plate making apparatus of another embodiment of the present invention.

FIG. 13 is an enlarged view showing a dot arrangement pattern of a plate making apparatus according to another embodiment of the present invention.

FIG. 14 is a block diagram showing a configuration of a conventional intaglio plate making apparatus.

FIG. 15 is a diagram showing a relationship between a conventional plate making pattern and a plate making timing signal.

FIG. 16 is a diagram showing a conventional plate making pattern.

[Explanation of symbols]

1 plate cylinder 2 plate sheet 3 plate cylinder rotating motor 4 ball screw 5 high power semiconductor laser 6 laser block moving motor 7 plate making recess 8 rotary encoder 9 plate cylinder rotating direction 10 laser block moving direction 11 plate making position detection circuit 12 digital delay Circuit 13 CPU 14 Correction amount calculation circuit 15 Data transfer control circuit 16 Image memory 17 Gamma conversion unit 18 Preload register 19 Conversion upper address register 20 Gamma conversion circuit 21 Conversion lower address unit 22 D / A conversion unit 23 Plate-making laser driver 100 Encoder clock 101 line reference signal 102 line start position signal 103 line end signal 104 plate making timing signal (dot start signal) 106 delayed line start position signal 107 delayed line end signal 108 delayed Post plate making timing signal (delayed dot start signal) 109 Delayed pre load signal 110 Read control signal 111 Next plate making data 112 Laser drive signal 113 Laser drive signal 114 Laser drive current 115 Gamma conversion clock 116 Plate making timing signal (dot start signal) 24 Distance on plate cylinder corresponding to 25 cycles 25 Delay distance 26 Delay distance 27 Delay distance 29 Delay distance 30 Start line 31 End line 32 Sub-scanning direction 33 Main scanning direction 34 Dots 35 Start line main scanning direction start position 36 Start line Main scanning direction start position 60 Delay selection terminal

Claims (5)

[Claims] 1. A dot forming means for forming dots with unevenness corresponding to plate-making data on a plate sheet rotating in the main scanning direction while moving in a sub-scanning direction orthogonal to the main scanning direction, and for rotating the plate sheet. A rotary encoder that synchronously generates an encoder clock having a predetermined number of pulses, a plate-making timing signal that starts the formation of each dot on the plate sheet from the encoder clock, and a line start position of each line in the main scanning direction. Plate making position detecting means for generating a signal, correction amount setting means for setting a correction amount for correcting the dot start position of each line, and delaying the plate making timing signal and the line start position signal based on the correction amount. A delay plate making timing signal and a delay line start position signal are output. Performs signal processing on the basis of the timing signal and the delay line start position signal, the plate making apparatus characterized in that the cut start position of each plate making line based on the correction amount so that the variable. 2. The plate making apparatus according to claim 1, wherein the delay means delays by using a clock for sampling the plate making data supplied to the dot forming means. 3. The plate making apparatus according to claim 1, wherein the gamma conversion is performed based on the delayed plate making timing signal, and the delay means delays by using a clock for performing the gamma conversion. And plate making equipment. 4. A dot forming means for forming dots with unevenness corresponding to plate-making data while moving in a sub-scanning direction orthogonal to the main scanning direction on a plate sheet rotating in the main scanning direction, and rotating the plate sheet. A rotary encoder that synchronously generates an encoder clock having a predetermined number of pulses, a plate-making timing signal that starts the formation of each dot on the plate sheet from the encoder clock, and a line start position of each line in the main scanning direction. Plate-making position detecting means for generating a signal, correction amount setting means for setting a correction amount for stepwise correcting the dot start position for each of a plurality of lines in the sub-scanning direction, signal processing based on the encoder clock, and The feature is that the plate making start position for each plate making line is made variable in multiple stages based on the correction amount. That plate making apparatus. 5. The plate making apparatus according to claim 4, wherein the correction amount is set in a plurality of steps based on the number of encoder clocks with respect to the deviation of the dot start position in the sub-scanning direction. And plate making equipment.