JPH04294886A - Method for controlling engraving - Google Patents

Abstract

PURPOSE:To improve the precision of the engraving of enlargement and reduction by deciding the positioning of the engraving pattern with the standard clock pulse number generated with the frequency higher than the standard pulse. CONSTITUTION:The standard clock pulse of the frequency higher than the standard pulse is generated, the positioning of the engraving pattern is decided with the standard clock pulse number. Because the standard clock pulse is synchronized with every generation of the standard pulse, even if it is on the way during one rotation, both are corresponded without the slipping state. Therefore, if the encorder of high percussion is not presented, the enlargement and reduction or the fine adjustment of the length to be worked, etc., can be executed beyond the range of resolution of the pulse encorder.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the engraving position of a plate-making material while enlarging or contracting it based on a document pattern in a laser plate-making apparatus that uses a laser beam to create irregularities on a plate-making material.

0002

2. Description of the Related Art For example, Japanese Patent Publication No. 55-17702 and Japanese Patent Application Laid-open No. 58-3795 disclose engraving methods using laser processing. When the document pattern is reduced or expanded in the circumferential direction during the laser engraving process, or when the outer diameter of the engraving roller and the printing roller are different during the printing process, the engraving roller is different from the outer diameter of the printing roller. Sometimes, the position data of the original pattern becomes the data of the engraving pattern after being adjusted by the adjustment coefficient.

[0003] Therefore, in the field of image transmission systems, the adjustment coefficient corresponds to a cooperation coefficient to make the original image and the received image similar. It can be defined as including a coefficient that adjusts for differences in diameter.

At the plate-making stage, the circumferential position of the document pattern on the reading roller and the circumferential engraving position on the engraving roller are detected by a rotary pulse encoder under a rotation scanning system. Therefore, machining accuracy is determined by the resolution of these pulse encoders.

For example, when positioning a machining pattern in units of 0.1%, a pulse train of 1000 pulses or more per pulse is required on the pulse encoder side of the engraving roller. Since manufacturing such a high-resolution pulse encoder is technically difficult, a simple positioning control method for engraving is desired.

[0006]

OBJECTS OF THE INVENTION Therefore, it is an object of the present invention to enable engraving control with the precision necessary for enlarging and reducing, without using a high-resolution pulse encoder, in a rotary scanning laser engraving process.

[0007]

In view of the above object, the present invention generates a reference clock pulse having a higher frequency than the reference pulse of the engraving roller, and determines the positioning of the engraving pattern by the number of reference clock pulses. .

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the overall configuration of a laser engraving processing apparatus 100. The controller 1 is connected to a laser oscillator 2 in order to control the output of the laser beam 9 based on the engraving control method of the present invention, and is also connected to the engraving roller 3.
are connected to motors 5, 8, and 13, respectively, to control the rotation of the common head 6, the feed of the common head 6, and the rotation of the reading roller 11.

The engraving roller 3 and the reading roller 11 are
They are arranged parallel to each other around the central axis, and are controlled by the controller 1 to always rotate in a synchronous state. The rotation amount of the engraving roller 3 and the reading roller 11 and the rotation speed of the motor 8 are detected by rotary type pulse encoders 4, 7, and 12 connected to them, and sent to the controller 1 as a pulse train.

Here, the circumferential length of the reading roller 11 corresponding to the pulse interval of the pulse encoder 12 and the circumferential length of the engraving roller 4 corresponding to the pulse interval of the pulse encoder 4 are set to be the same. There is.

By rotating the feed screw shaft 14, the motor 8 moves the common head 6, which is integrated with the feed nut 15, between the parallel engraving roller 3 and the reading roller 11 into the scanner fixed to the common head 6. 10 and mirror 16 in the reading direction.

Note that the scanner 10 has a reading roller 1
Original pattern 1 of original 17 attached to the circumferential surface of 1
8 is optically read, converted into electrical original data (read output signal), and sent to the controller 1. Further, the mirror 16 guides the laser beam 9 to the circumferential surface of the engraving roller 3, and performs plate-making processing to create necessary irregularities on the plate-making material 19 attached to the circumferential surface of the engraving roller 3 based on the engraving pattern 20.

The controller 1 also includes a clock oscillation circuit 21, a clock counter 22, and a counter 23 for engraving positioning. FIG. 3 shows an example.

The clock oscillation circuit 21 generates a reference clock pulse of a frequency set by the frequency setter 24 and sends it to the input terminal of the clock counter 22 and one input terminal of the AND gate 27. The AND gate 27 receives the output of the clock counter 22 at its other input terminal and sends it to the input terminal of a counter 23 for engraving positioning. Note that the count values of the clock counter 22 and the counter 23 are set by setters 24 and 25, respectively, based on the adjustment coefficient.

Next, FIG. 3 shows the order in which the original pattern 18 is enlarged and a corrected engraving pattern 20 is obtained based on the engraving control method of the present invention in relation to a pulse train.

During machining, the controller 1 controls the motor 5,
By controlling the rotational speed of the engraving roller 3
and the reading rollers 11 are rotated in a synchronous state. At this time, the pulse encoder 4 generates a reference pulse that equally divides one rotation with the rotation scan start position of the engraving roller 3 as the origin position, and sends it to one input terminal of the clock counter 22 inside the controller 1.

On the other hand, the clock oscillation circuit 21 continuously generates a reference clock pulse at a frequency sufficiently higher than that of the reference pulse. Here, when enlarging the original pattern 18 in units of 0.1 [%], the necessary frequency of the reference clock pulse must be set to a value that delivers 1000 pulses or more per one reference pulse. After the start of operation, when the motors 5, 8, and 13 reach steady rotation, the controller 1 gives a count start command to the clock counter 22 and the counter 23.

Then, the clock counter 22 starts counting the reference clock pulses and generates an "H" level output during counting, but when a predetermined count value, for example "100" is generated, the clock counter 22 starts counting reference clock pulses.
At the point when only "0" has been counted, the counting operation is stopped and an "L" level output is generated and sent to one side of the AND gate 27. Note that the predetermined count value is set in advance by the setting device 25. After this, when the next reference pulse is input to the clock counter 22, the clock counter 22
starts the counting operation again and reaches the predetermined count value "100".
0'', stop the counting operation, and wait for the next reference pulse to arrive.

In this manner, the clock counter 22 counts the reference clock pulses in the interval between two reference pulses, counts a predetermined count value before the arrival of the next reference pulse, and then stops. The counting operation is performed in synchronization with the reference pulse.

On the other hand, since the clock counter 22 generates an "H" level output until it reaches a predetermined count value, the reference clock pulse is generated by the AND gate 2.
Counter 2 for engraving positioning enters from the other input of 7.
It also serves as the input for 3. Counter 2 for engraving positioning
3 performs a reference clock pulse counting operation only during the counting operation of the clock counter 22, and when a predetermined count value set by the setting device 25 is reached, one engraving reference pulse is generated, and this engraving is performed. It self-resets with the reference pulse and prepares for the next count. Here, the predetermined count value of the counter 23 is obtained by [predetermined count value "1000" x adjustment coefficient] of the clock counter 22,
For example, it is set as "1015" for enlargement. Therefore, the engraving reference pulse is sent out every 1015 reference clock pulses in synchronization with the generation of the reference pulse, and in the process of elapsed time in the circumferential direction from the origin position of the rotation scan, the engraving reference pulse is sent out by the adjustment coefficient. It is occurring on a proportional basis. Of course, this amount of shift corresponds to the increment for expansion.

[0021] Therefore, the controller 1 controls the scanner 10.
The reference pulse corresponding to the change point of the original pattern 18 read by the rotational scanning is read as the number of pulses from the origin position, the engraving reference pulse corresponding to this number of pulses is specified, and the laser is The output of the oscillator 2 is adjusted, and the processing depth of the plate-making material 19 is changed by the energy of the laser beam 9, thereby forming an uneven surface on the surface of the plate-making material 19. Therefore, the modified engraving pattern 20 is gradually enlarged and shifted in proportion to the original pattern 18 from the original position.

The original data can also be imported from the image scanner 28, external storage device 29, CAD 30, or the like. Note that the convex portion is formed with a shoulder portion (slope portion) around the periphery to prevent deformation due to printing pressure. In order to form this shoulder part, the controller 1 reads in advance a count number corresponding to the width of the shoulder part.

[0023]

In the above embodiment, the position of the original pattern 18 is read at the generation position of the reference pulse, and the positioning for engraving is determined from the generation position of the engraving reference pulse. Therefore, there is no position reading between two reference pulses or positioning between two engraving reference pulses.

However, for positioning for reading or engraving, changing points of the original pattern 18 are determined by using the AND gate 2.
The reference clock pulse number of the counter 23 can also be read as the output of the AND gate 27 corresponding to the value obtained by multiplying the reference clock pulse number by the adjustment coefficient for positioning for engraving. It can also be determined by the number of pulses. In this case,
The reference clock pulses as the output of the AND gate 27 are all in a synchronized state every time the reference pulse is generated, so compared to the synchronized state of each rotation of the engraving roller 3 and the reading roller 11, there is a difference in synchronization. The amount is small.

Further, in the above embodiment, the means for generating the engraving reference pulse is explained as a counter for convenience of explanation, but the same function can also be realized in the field of a software program.

[0027]

According to the present invention, even if a highly accurate encoder is not available, scaling and fine adjustment of machining length can be performed beyond the resolution range of a pulse encoder. In particular, since the reference clock pulse with a higher frequency than the reference pulse is converted into a pulse in synchronization every time the reference pulse is generated, there is no accumulation of errors during one rotation, and within the generation interval of the two reference pulses. The amount of error is minimized.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a laser engraving apparatus.

FIG. 2 is a block diagram of a pulse conversion section.

FIG. 3 is a time chart of pulse trains corresponding to a document pattern and an adjusted engraving pattern.

[Explanation of symbols]

1 Controller 2 Laser oscillator 3 Engraving roller 6 Common head 9 Laser light 10 Scanner 11 Reading roller 14 Feed screw shaft 18 Manuscript pattern 19 Plate making materials 20 Engraving pattern 21 Clock oscillation circuit 22 Clock counter 23 Counter for engraving positioning 100 Laser engraving processing equipment

Claims (1)

[Claims] Claim 1: In a laser engraving processing device that engraves a engraving material on the peripheral surface of an engraving roller with a laser beam based on original data, a reference clock pulse having a higher frequency than a reference pulse synchronized with the rotation of the engraving roller is generated. ,
While synchronizing with the above reference pulse, engraving reference pulses are created for each adjustment factor times the number of reference clock pulses, and engraving is performed at a position from the origin on the circumference of the engraving roller that corresponds to the number of pulses of this engraving reference pulse. An engraving control method characterized by engraving a plate-making material on a roller with a laser beam.