JPH0524171A - Semiconductor laser plate making apparatus - Google Patents

Abstract

PURPOSE:To manufacture a plate cylinder capable of performing finer multi- gradatin expression by changing the depth and area of a plate corresponding to the light and shade of image data at the time of manufacture of a gravure plate using semiconductor laser. CONSTITUTION:When cavities 15 are formed on a plate corresponding to the light and shade of image data 41 by semiconductor laser 10, the rotational speed of a plate cylinder 1 is changed corresponding to light and shade to obtain a plate 2 changed in depth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser plate making apparatus which uses a semiconductor laser to form a recessed plate corresponding to the density of image data.

[0002]

2. Description of the Related Art The applicant of the present invention has previously disclosed Japanese Patent Laid-Open No. 2-139238.
In the publication, a plate making apparatus was proposed in which a plate made of a thermoplastic resin was irradiated with a laser beam using a laser to obtain a plate cylinder of an intaglio plate in which a concave portion corresponding to the shade of an image was formed.

The outline of the configuration disclosed in the above publication will be described with reference to FIG. FIG. 6 is a conceptual diagram of an optical system showing a pattern forming method 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 mother screw drilled in the plate cylinder 1 with a flat head screw or the like. Any appropriate fixing method can be selected as the fixing method, and for example, the back surface of the plate 2 can be coated with an adhesive and fixed to the plate cylinder.

As a material for the plate 2, a thermoplastic resin having a relatively narrow melting point distribution range, having a hardness during curing, and a resin that scatters or sublimes at a low temperature during melting is preferable. For example, polyethylene resin, acrylic resin, polypropylene. A resin containing about 20% carbon is used.
The thickness of the plate 2 is selected to be about 200 μm.

The plate cylinder 1 is connected to a plate cylinder rotation motor which will be described later, and the plate cylinder 1 is rotated in the direction of arrow B.

FIG. 6 shows a conceptual diagram for forming the recess 15 in the plate 2 using the semiconductor laser 10 of about 1 W.

The video input signal 16 captured by an image scanner or the like is supplied to the semiconductor laser 10, and the drive current is directly turned on / off by the PCM video input signal 16. Therefore, the laser beam emitted from the semiconductor laser 10 blinks in synchronization with the video signal. The laser beam emitted from the semiconductor laser 10 is collimated by the collimating optical system 12 and is irradiated through the focusing lens 13 so as to focus on the surface position of the plate 2.

Semiconductor laser 10 and collimating optical system 1
2. The laser block 14 including the focusing lens 13 is initially focused on a predetermined position on the leftmost end side of the plate cylinder 1.
Since the plate cylinder 1 is rotated in the direction of the arrow B by a plate cylinder rotating motor described later, when the plate cylinder 1 is rotated once, the depression 15 for one track along the circumference is scattered by the laser beam. Then, the depression 15 for one predetermined track is formed. Next, the laser block 14 is moved in the axial direction of the plate cylinder 1 for one pixel, and the synthetic resin material is scattered to form a predetermined recess 15 in two tracks. When such scanning is sequentially performed over the entire surface of the plate cylinder 1, the synthetic resin material forms the depression 15 corresponding to the shade of the image input signal 16.

That is, the plate cylinder 1 is irradiated with a laser beam through a focusing lens 13 to focus on the surface of the synthetic resin plate 2 to melt the plate surface and scatter or sublime the synthetic resin.

The laser beam 11 emitted from the semiconductor laser 10 is emitted from the minute active layer region 10a as shown in FIG. 7, and the cross section of the light beam at a position near the light emitting point is substantially rectangular.
The size is about 200 μm in width × 1 μm in thickness, and the cross section of the laser beam spot 10b projected on the plate 2 through the collimating optical system 12 and the focusing lens 13 in the laser block 14 is substantially rectangular and its size is wide. 120 μm x
The thickness is about 1 μm.

The laser beam spot 10b having a rectangular cross section is moved in the thickness direction to form the depression 15 on the plate 2 according to the density of predetermined image data. That is, the plate cylinder 1 on which the plate 2 is wound is rotated at a constant speed by a plate cylinder rotation motor as shown in the characteristic diagram 48 of FIG. 8A,
As described above, the semiconductor laser 10 receives the video input signal 16
8B, a constant current I as shown in FIG. 8B is caused to flow based on the ON and OFF signals, and the duration of the ON periods t ₁ , t ₂ and t ₃ causes the plan view of FIG. 8C and the partial sectional view of FIG. 8D. As shown, the depression 15 corresponding to the image data on the plate 2
Is formed to have a predetermined area S and a predetermined depth d.

As can be seen from FIGS. 8A, 8B, 8C and 8D, the plate cylinder 1 is driven at a constant rotation speed, and the current supplied to the semiconductor laser 10 also has a constant current value I. The depth d of the depression 15 formed in the plate 2 at the time of turning on is constant depending on the drive current I, and the grayscale expression is mainly determined by the area S of the depression 15.

[0013]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Considering the life, the drive current I that flows when 0 is on is an appropriate current that can output about 70 to 90% of the full power of the semiconductor laser and does not flow at all when off, or a small amount of current for laser protection. It was about to run. Like this (Fig. 8
(See A, B, C, D) If the ON period is changed according to the contrast of the image data with a constant drive current and the plate cylinder 1 is rotated at a constant speed, the depressions 15 having different areas S corresponding to the image data are formed. It is possible to form a gradation by forming a pattern, but since the depth d of the depression 15 formed in the plate 2 is always constant, there is little change in the depth direction, and the characteristic of gravure printing There was a problem that gradation expression in the thickness direction could not be performed.

Further, when the depression 15 for one pixel having a large area S is formed on the plate 2, the depression 1 for one pixel having a small area S is formed.
It takes the same time to make 5, so a small dent 1
There was a problem that the waste of plate-making time was large when the No. 5 was produced.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to form a shade 15 of image data when forming a recess 15 in a plate cylinder 1 around which a plate 2 is wound. In accordance with the above, there is provided a semiconductor laser plate making apparatus in which the rotation speed of the plate cylinder is changed so that the depth of the depression 15 is changed according to the lightness and darkness.

[0016]

As shown in FIG. 1, a plate making apparatus of the present invention uses a semiconductor laser to form a depression in the plate according to the shade of image data. In the plate-making apparatus, the rotational speed of the plate cylinder 1 around which the plate 2 is wound is changed according to the shade of the 1-pixel data 41, so that multi-tone expression is performed.

[0017]

In the semiconductor laser plate making apparatus of the present invention, when the plate wound around the plate cylinder is irradiated with the laser beam from the semiconductor laser to form the depressions of the gravure plate on the plate surface, the plate cylinder is rotated. The rotation speed of the motor is changed according to the density of the image data, so that the pixels with high density are deep and the pixels with light density are shallow, so that it is possible to express in multiple gradations by changing the depth direction of the recess. Things are obtained.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor laser plate making apparatus of the present invention is shown in FIG.
5 to FIG. Prior to describing the present invention with reference to FIG. 1, the overall configuration of the laser plate making apparatus of this example will be described with reference to FIG.

FIG. 2 is a perspective view of a semiconductor laser plate making apparatus used in this embodiment. Reference numeral 11 denotes a base of the semiconductor laser plate making apparatus, in which a plate cylinder rotating portion 62 and a laser block moving portion 63 are provided on a substantially rectangular steel plate. It is provided. The plate cylinder rotating portion 62 is configured such that the substantially cylindrical plate cylinder 1 is rotatably pivoted between the left and right side walls 64L and 64R formed in a substantially V shape, and the plate cylinder rotating motor 7 disposed on the base 11 The laser block 14 is driven so as to include the semiconductor laser 10 and move along a guide portion 22 arranged along the axial direction of the plate cylinder 1.

A synthetic resin plate 2 is wound and fixed along the outer circumference of the cylindrical portion of the plate cylinder 1. Metal caps 3L and 3R are fitted to the left and right of the plate cylinder 1, and left and right caps 3L and 3R
Shafts 4L and 4R formed integrally with the left and right side walls 64L and 64
It is rotatably and pivotally attached to R. The shaft 4R is connected to a plate cylinder rotating motor 7 fixed on a base 11 via a plurality of pulleys 6 ... And a belt 5 ... And wound around the plate cylinder 1 via these pulleys 6 and a belt 5. Version 2 is arrow A or B
Rotate in the direction.

In the laser block moving portion 63, a substantially rectangular sub base 65 is mounted on a dogleg shaped step portion formed on the left and right side walls 64L and 64R of the base 11.
A guide part 22 is formed on the upper part 5.

Further, on the sub-base 65, the bearing portion 23L,
23R is planted, the ball screw 26 of the laser block moving unit 63 is bridged between these bearings 23L and 23R,
The ball screw 26 is rotationally driven by the laser block moving motor 24. That is, the ball screw 26 is the shaft of the laser block moving motor 24 and the shaft coupling 25 for coupling.
To drive the ball screw 26.

A mover 27 is screwed onto the ball screw 26, the mover 27 and a laser block mount 28 are fixed by an arm 29, and the laser block 14 is placed on the laser block mount 28. Laser block 14
Is moved along the guide portion 22 in the axial direction of the plate cylinder 1, so that the laser beam 11 emitted from the semiconductor laser 10 in the laser block 14 is moved along the X and Y axes of the plate 2 wound around the plate cylinder 1. The depressions 15 can be formed so as to face each other in all directions.

Using such a semiconductor laser plate making apparatus,
A method of forming the gravure plate 2 will be described with reference to the system diagram of FIG.

In FIG. 1, the input operation unit 30 sends a status signal 31 such as stop or reset to a microcomputer (hereinafter C
It is referred to as PU) 32. The CPU 32 supplies a forward rotation or reverse rotation pulse to the laser block moving motor driver 33 to drive the laser block moving motor 24 to rotate. Further, the CPU 32 supplies a pulse having a preset frequency to the plate cylinder rotating motor driver 35 via the pulse generator 44 so that the plate cylinder rotating motor 7 turns off the plate cylinder 1 (when no pixels are formed). ) Is specified.

When it comes to the pixel portion for plate making, the CPU 32
Reads the digital image data 41 captured by the image scanner or the like into the data RAM 38 from the data RAM 38 and sends it to the gray scale conversion circuit 42. The gray scale conversion circuit 42 has a frequency table for rotation of the plate 1 prepared in advance, and this frequency table is 2 k when the gradation value of the pixel data 41 is represented by 255, for example.
Similarly, the frequency corresponding to the image data is 4 kHz when it can be represented by 128, and the frequency corresponding to the image data is the storage means 4 such as ROM or RAM.
Stored in 5.

Similarly, the gray scale conversion circuit 42 has an irradiation time table for converting the irradiation time of the semiconductor laser 10 into short and short. This irradiation time table is 200 when the value of the image data 41 is represented by 255 in gradation. Similarly, the irradiation time value (pulse number = pulse width) when the semiconductor laser 10 is turned on according to the value of the image data 41 is 100 pulses or the like when represented by 128, and the ROM or RAM.
It is stored in the storage means 46 such as.

The gray scale conversion circuit 42 uses the frequency table 45 and the irradiation time table 46, for example, when the gradation value of the image data is 255, the plate cylinder rotation motor 7 is used.
Drive frequency is 2 kHz and the number of pulses when the semiconductor laser 10 is on is 200 pulses. Similarly, when the gradation value of the image data is 128, the drive frequency of the plate cylinder rotation motor 7 is 4 kHz.
The pulse when the semiconductor laser 10 is turned on at 100 Hz is 100 pulses or the like, and the irradiation time value and the frequency value are supplied to the pulse generator 44. The pulse generator 44 changes the frequency based on the frequency value and the irradiation time value and sends a control signal for the irradiation time of the semiconductor laser 10 to the plate cylinder rotating motor 7. After that, the frequency is returned to the preset frequency of the plateless portion.

Further, an ON / OFF signal is supplied to the laser driver 43 from the gray scale conversion circuit 42, and a predetermined current is supplied to the semiconductor laser 10 according to the ON / OFF signal to irradiate the laser beam on the plate 2. The plate cylinder 1 is rotated by the plate cylinder drive motor 7, and the recess 15 corresponding to the data of the image input signal 16 is formed on the plate surface by the semiconductor laser 10. When rotated, the laser block moving motor 24 is moved by one pixel data, and the CPU 32 controls so as to form the depression 15 corresponding to the shading of the screen along the circumference of the plate cylinder 1.

FIG. 3A is a graph in which the vertical axis represents the rotational speed of the plate cylinder 1 and the horizontal axis represents time. The current supplied to the semiconductor laser 10 is a constant current I as shown in FIG.
The rotation speed of the plate cylinder 1 during the ON period when a current is applied to 0 has a different value for each pixel. That is, the plan view of FIG.
As shown in the partial cross-sectional view of D, the rotation speed of the plate cylinder 1 is S
Slowly rotate slowly like ₁ to lengthen the irradiation time of the laser beam, to make the rotation speed of the plate cylinder 1 medium for the pixel 15B having a medium temperature like S ₂ , and to make the plate 15C with a light density the plate. The rotation speed of the body 1 is increased as in S ₃ to shorten the irradiation time of the laser beam. In this way, a deep depression d ₁ , a medium depression d ₂ , and a shallow depression d ₃ can be formed corresponding to the rotation speed (irradiation time).

In the present invention, since the depressions 15 can be changed in the depth direction, it is possible to express gradation by giving the printed matter a change in the ink thickness direction. In addition, it is possible to reduce the time wasted when making small depressions, and for example, the plate making time can be considerably shortened for a plate having many characters and light pixels.

In the above-described embodiment, while changing the irradiation time of the semiconductor laser 10, the rotation speed of the plate cylinder 1 is changed and the depression 15 is formed.
The example in which the depth of the recess 15 is changed has been described. However, as shown in FIGS. 4A, 4B, 4C, and 4D, the depth d ₁ of the depression 15 is changed by changing the irradiation time of the semiconductor laser 10 and the change amount of the rotation speed of the plate cylinder _1. , D ₂ ,
Both d ₃ and the area S of the pixels 15A to 15C can be changed.

Furthermore, as shown in FIGS. 5A, 5B, 5C and 5D, the current value of the semiconductor laser 10 is changed to I ₁ , I ₂ and I ₃ to change the power output of the semiconductor laser 10 and the rotational speed of the plate cylinder 1. It is also possible to form the depression 15 by changing S to S ₁ , S ₂ and S ₃ . For example, in one pixel 15A and 15B, the depth may be changed as d ₃ , d ₄ and d ₁ , d ₂ to express gradation.

According to the semiconductor laser plate making apparatus of this example, the plate 2
Since the area S can be varied in the depth direction of the depressions 15, the printed matter on which the gravure printing is performed using the plate manufactured in this example has a variation in the original ink thickness of the gravure printing. Both gradation expression and area gradation expression can be changed, finer multi-gradation printing can be performed, and plate making time can be shortened.

[0035]

According to the semiconductor laser plate making apparatus of the present invention, since it is possible to change both the depth and the area of the depression of the plate made by plate making, it is possible to change the thickness direction and the area of the printed matter. In addition, it is possible to obtain finer gradations and to shorten the plate making time with a plate having many light pixels.

[Brief description of drawings]

FIG. 1 is a system diagram of a semiconductor laser plate making apparatus according to the present invention.

FIG. 2 is a perspective view of a semiconductor laser plate making apparatus according to the present invention.

FIG. 3 is an explanatory diagram of changes in waveform and depression of the semiconductor laser plate making apparatus of the present invention.

FIG. 4 is another explanatory view showing changes in the waveform and the depression of the semiconductor laser plate making apparatus of the present invention.

FIG. 5 is still another explanatory view showing changes in the waveform and the depression of the semiconductor laser plate making apparatus of the present invention.

FIG. 6 is a conceptual diagram of an optical system showing a conventional laser scanning system.

FIG. 7 is a pattern explanatory diagram of a semiconductor laser used in a conventional semiconductor laser plate making apparatus.

FIG. 8 is a diagram illustrating a waveform and a depression of a semiconductor laser used in a conventional semiconductor laser plate making apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 plate cylinder 2 plate 10 semiconductor laser 43 laser driver 44 pulse generator 45 frequency table storage means 46 irradiation time table storage means

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[Procedure amendment]

[Submission date] March 24, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

The present invention relates to a semiconductor laser plate making apparatus which was set to form the Mino plate recess corresponding to the shade of image <br/> image data by using a semiconductor laser.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007] images input signal 16 taken in by an image scanner or the like is supplied to the semiconductor laser 10, on the drive current images input signal 16 has been turned into PCM, directly modulated off. Therefore the laser beam emitted from the semiconductor laser 10 flashes in synchronization with the images signals. The laser beam emitted from the semiconductor laser 10 is collimated by the collimating optical system 12 and is irradiated through the focusing lens 13 so as to focus on the surface position of the plate 2.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Semiconductor laser 10 and collimating optical system 1
2. The laser block 14 including the focusing lens 13 is initially focused on a predetermined position on the leftmost end side of the plate cylinder 1.
Since the plate cylinder 1 is rotated in the direction of the arrow B by a plate cylinder rotating motor described later, when the plate cylinder 1 is rotated once, the depression 15 for one track along the circumference is scattered by the laser beam. Then, the depression 15 for one predetermined track is formed. Next, the laser block 14 is moved in the axial direction of the plate cylinder 1 for one pixel, and the synthetic resin material is scattered to form a predetermined recess 15 in two tracks. By performing such a scanning sequentially across the entire surface of the plate cylinder 1 synthetic resin material to form a recess 15 corresponding to the shade of images input signal 16.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

The laser beam 11 emitted from the semiconductor laser 10 is emitted from the minute active layer region 10a as shown in FIG. 7, and the oscillation region is substantially rectangular, and its size is, for example, width 200 μm × thickness. Laser block 1 with a size of about 1 μm
The cross section of the laser beam spot 10b projected on the plate 2 via the collimating optical system 12 and the focusing lens 13 in 4 is substantially rectangular, and its size varies depending on the optical system.
For example, the width is about 120 μm and the thickness is about 1 μm.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

The laser beam spot 10b having a rectangular cross section is moved in the thickness direction to form the depression 15 on the plate 2 according to the density of predetermined image data. That is, the plate cylinder 1 on which the plate 2 is wound is rotated at a constant speed by a plate cylinder rotation motor as shown in the characteristic diagram 48 of FIG. 8A,
As described above in the semiconductor laser 10, images input signal 16
8B, a constant current I as shown in FIG. 8B is caused to flow based on the ON and OFF signals, and the duration of the ON periods t ₁ , t ₂ and t ₃ causes the plan view of FIG. 8C and the partial sectional view of FIG. 8D. As shown, the depression 15 corresponding to the image data on the plate 2
Is formed to have a predetermined area S and a predetermined depth d.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0019

[Correction method] Change

[Correction content]

FIG. 2 is a perspective view of a semiconductor laser plate making apparatus used in this embodiment. Reference numeral 11 is a base of the semiconductor laser plate making apparatus. A plate cylinder rotating part 62 and a laser block moving part 63 are provided on a substantially rectangular steel plate. Be done. The plate cylinder rotating portion 62 is configured such that the substantially cylindrical plate cylinder 1 is rotatably pivoted between the left and right side walls 64L and 64R formed in a substantially V shape, and is rotated by the plate cylinder rotation motor 7 disposed on the right side wall 64R . The laser block 14 includes the semiconductor laser 10 and is moved along a guide portion 22 arranged along the axial direction of the plate cylinder 1.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

A synthetic resin plate 2 is wound and fixed along the outer circumference of the cylindrical portion of the plate cylinder 1. Metal caps 3L and 3R are fitted to the left and right of the plate cylinder 1, and left and right caps 3L and 3R
Shafts 4L and 4R formed integrally with the left and right side walls 64L and 64
It is rotatably and pivotally attached to R. The shaft 4R is connected to a plate cylinder rotating motor 7 fixed on the right side wall 64R via a plurality of pulleys 6 ... And a belt 5 ..., and is wound around the plate cylinder 1 via these pulleys 6 and a belt 5. The printed plate 2 rotates in the direction of arrow A or B.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

When it comes to the pixel portion for plate making, the CPU 32
Reads the digital image data 41 captured by the image scanner or the like into the data RAM 38 from the data RAM 38 and sends it to the gray scale conversion circuit 42. Grayscale conversion circuit 42 has a frequency table of the manufacturing version times diverted prepared in advance, 2 kHz when the value of the gradation of the frequency table for example, the pixel data 41 is represented by 255
Similarly, when it can be represented by 128, the frequency corresponding to the image data such as 4 kHz is stored in the storage means 45 such as the ROM or the RAM.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

Similarly, the gray scale conversion circuit 42 has an irradiation time table for converting the irradiation time of the semiconductor laser 10 into short and long . This irradiation time table is, for example, 200 pulses when the value of the image data 41 is represented by a gradation of 255, 100 pulses when it is similarly represented by 128, and when the semiconductor laser 10 is turned on according to the value of the image data 41. Irradiation time value (number of pulses = pulse width) of ROM or RAM
It is stored in the storage means 46 such as. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 24, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 6

[Correction method] Change

[Correction content]

[Figure 6]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction content]

[Figure 7]

Claims (1)

Claim: What is claimed is: 1. A semiconductor laser plate making apparatus, wherein a semiconductor laser is used to form depressions in a plate in accordance with the density of image data, and the rotation of a plate cylinder around which the plate is wound. A semiconductor laser plate making apparatus characterized in that the speed is changed in accordance with the shading of the image data so that multi-gradation is expressed.