JP2942290B2 - Information writing position control device for laser plate making machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a laser plate making machine, which determines information to start writing from a leading end in a feeding direction of information to be written by a laser beam on a charged plate. The present invention relates to a writing position control device.

(Prior Art) In recent years, a laser plate making machine that forms an original plate for printing using an aluminum photosensitive plate material having an organic optical semiconductor layer formed thereon is known.

As shown in FIG. 5, this type of laser plate making machine employs a plate 1
A plate feeding roller 4 for conveying the plate 1 set in the set unit 2 in the downstream direction along the conveying path 3, a charging unit 5 for uniformly charging the surface of the plate 1, A laser irradiation unit 6 for irradiating the plate 1 with a laser beam 6a modulated by an image signal to form an electrostatic latent image, and immersing the plate 1 in a developer containing toner and developing the electrostatic latent image with toner Developing unit 7, a squeeze roller unit 8A for removing excess developer adhering to the plate 1, a cleaning unit 8B for removing dirt from the squeeze roller, a drying unit 9 for drying the plate 1, and a transfer unit. And a fixing unit 10 for fixing the formed toner image.

In such a laser plate making machine, when image information or the like is written on the plate 1 after being charged by the charging unit 5 with the laser beam 6a from the laser irradiation unit 6, the scanning for writing is started by transferring the plate. This is performed from a position separated by a predetermined distance from the front end in the direction.

Conventionally, as a writing position control method for determining such a writing start position of a laser beam, one photoelectric sensor for detecting the leading edge of the plate 1 in the feeding direction is provided before the irradiation position of the laser beam 6a. , This sensor is version 1
A counter measures the time (distance) from the time when the leading edge is detected to the writing start position, and sends a writing command to the laser irradiation unit 6 when the counted value reaches a set value.

(Problems to be Solved by the Invention) By the way, when the plate 1 is formed into a predetermined size, the plate 1 is mechanically cut by shearing or the like.
The cut surface has irregularities of 0.1 mm or more.

Therefore, in the conventional method in which the leading edge having such unevenness is detected by one sensor, the unevenness of the leading edge of the plate directly reflects on the detection operation of the sensor, and this causes variation in the distance from the leading edge of the plate to the writing position. If it is increased, the writing position accuracy of the laser beam is reduced.

When printing multi-colored posters by setting multiple printing plates whose printing positions vary widely on each plate cylinder of the printing press and printing multicolored posters, etc., the relative position of each printing plate is marked with a registration mark so that color misregistration does not occur. Attempting to adjust them together has a problem that the amount of adjustment is large and it takes much time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides an information writing position control device for a laser plate making machine capable of greatly reducing the variation in the writing position on a plate by a laser beam and improving the writing position accuracy. The purpose is to:

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a charging unit, a laser irradiation unit, a developing unit, and a fixing unit along a transport path, and transports a plate on the transport path. In the laser plate making machine for plate making, the plate is disposed at the position of the conveyance path on the upstream side of the laser irradiating section, is disposed at a linear interval in a direction orthogonal to the plate transfer direction, and the plate is transferred. A plurality of sensors that perform a detecting operation corresponding to the uneven shape of the leading edge by detecting that the leading edge on the front side in the transport direction of the plate at a different position in the direction orthogonal to the direction passes through the conveyance path location, A counter for counting the transport distance of the plate,
Average value calculation means for capturing the count value of the counter at the time of detection each time at least one of the sensors detects the leading edge of the plate, and calculating an average value of the respective count values captured corresponding to each sensor. And a write position calculating means for calculating a write position based on the average value from the average value calculating means.

(Function) A plurality of sensors arranged linearly at intervals in a direction perpendicular to the plate transport direction are provided with front end edges at different positions in the direction perpendicular to the plate transport direction. Detects that the vehicle passes through the transport path, the counter value at the time of detection is extracted in the order in which the leading edge is detected, and is sent to the average value calculating means. Then, the average value calculating means taking in these count values calculates the average value of each count value and sends it to the writing position calculating means. The writing position calculating means outputs a writing command based on the average value, and thereby determines a constant distance from the leading edge of the plate to the writing position.

Therefore, even if the leading edge of the plate is uneven, the variation in the writing start position due to this is reduced, and the accuracy of the writing start position can be improved.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIGS. 1 to 4 show an embodiment of an information writing position control apparatus for a laser plate making plate according to the present invention. FIG. 1 is an overall configuration diagram, and FIG. FIG. 3 is a plan view showing the positional relationship, FIG. 3 is a side view thereof, and FIG.

First, in FIG. 2 and FIG.
Are provided with plate feed rollers 4A and 4B separated by a predetermined distance.

A plate press roller 11 is disposed near the front side of the plate feed roller 4B, and a laser beam 6a for writing information is scanned between the plate press roller 11 and the plate feed roller 4B in a direction parallel to the roller axis. Is configured.

In the vicinity of the front side of the plate pressing roller 11, along a direction parallel to the axis thereof, that is, along a direction orthogonal to the transport direction of the plate 1 conveyed by the plate pressing roller 11, a plurality of photoelectric type Sensors (three in the embodiment) 12a to 12c are arranged in a straight line. The sensors 12a to 12c detect that the leading edge on the front side in the transport direction of the plate 1 passes at a plurality of points at different positions in the width direction (positions in the direction orthogonal to the transport direction of the plate 1). .

 Next, the configuration of FIG. 1 will be described.

In the figure, a counter 13 counts the feed distance of the plate 1 to the laser beam irradiation position side, and starts counting from the time when the plate 1 starts to be transferred by a predetermined amount to the sensors 12a to 12c by the plate feed roller 4A. I do.

When each of the sensors 12a to 12c detects the leading edge of the plate 1, the count value capturing circuit 14 counts the counter 13 at each detection time.
The counting content captured by the counting value capturing circuit 14 is output to the average value calculating circuit 15.

The average value calculation circuit 15 calculates the average value of the count values taken in every detection operation of each of the sensors 12a to 12c, and sets a reference point for determining the information writing position of the plate 1.

The writing position calculation circuit 16 calculates and determines the distance from the reference point obtained by the average value calculation circuit 15 to the information writing position on the plate 1.
The count value of the counter 13 and the writing position setting circuit 17
The setting value from is input.

 Next, the operation will be described.

First, when the plate 1 starts to be conveyed in the transfer direction A shown in FIGS. 2 and 3 by the rotation of the plate feed rollers 4A and 4B, the counter 13 starts the counting operation.

The leading edge of the plate 1 where the irregularities 1a are generated as the sheet is successively transported in the transport direction A by the plate feed roller 4A is detected by the sensor.
When approaching 12a to 12c, the sensor 12a which first detects the leading edge operates as shown in FIG. 4, and sends the detection signal to the count value acquisition circuit 14.

Accordingly count latching circuit 14 takes in the count value of the counter 13 at the present time t ₁ that is counting, and sends this to the average value calculation circuit 15.

Similarly, at times t ₂ and t ₃ at which the sensors 12 b and 12 c detect the leading edge of the plate 1, the detection signals are sequentially sent to the count value acquisition circuit 14.
, The count value of the counter 13 is taken into the count value taking circuit 14 and sent to the average value calculating circuit 15.

The average value calculating circuit 15 calculates an average value Sa by adding all the counted values and dividing by the number of sensors. This average value Sa is output to the writing operation circuit 16 as a reference point for determining the information writing position of the plate 1.

On the other hand, the write operation circuit 16 fetches the set value Sb from the write position setting circuit 17 and calculates the set value Sb and the average value.
The count value is determined by comparing Sa with a value obtained by subtracting the current count value Sc of the counter 13 from the current count value Sc. Then, when the counting is completed, a write command is output.

This write command is transmitted to the laser irradiating unit 6 for writing information.
By operating the laser irradiation unit 6 to output the laser beam 6a, the information is written on the plate 1 from the position set by the set value Sb.

In this embodiment, the plate 1 is disposed at a linear interval in the direction perpendicular to the direction of transport of the plate 1 and at a different position in the direction perpendicular to the direction of transport of the plate 1 in the forward direction of the plate. Sensors that detect when the leading edge of the side passes
A detection operation corresponding to the uneven shape of the leading edge of the plate 1 is performed by 12a to 12c. The average position of the leading edge of the plate 1 having the irregular shape is obtained from the average value of the counter values obtained by the detection operations of the plurality of sensors 12a to 12c, and the information writing position for the plate 1 is determined from this position. Therefore, even if the leading edge of the plate 1 has irregularities, the variation of the information writing position of the plate 1 can be reduced, the accuracy of the information writing position can be improved accordingly, and each of the information after setting on the plate cylinder of the printing press can be improved. The amount of plate alignment adjustment is reduced,
The adjustment work can be performed easily and in a short time.

In the above embodiment, the case where the counter 13 performs the count operation at the same time as the start of the feeding of the plate 1 has been described, but the present invention is not limited to this.

For example, the counting operation of the counter 13 may be started from the time when any of the sensors 12a to 12c first detects the leading edge of the plate 1. In this case, version 1
Each time the sensor for detecting the leading edge of the plate 1 detects the leading edge of the plate 1, the count value of the counter 13 is taken in. More specifically, for example, if the sensor 12a first detects the leading edge of the plate 1, this causes the counter 13 to start operating, and then the sensors 12b and 12c detect the leading edge of the plate 1, respectively. Then, the arithmetic circuit 15 calculates the average value of the count value captured during the detection operation of the sensor 12b and the count value captured during the detection operation of the sensor 12c.

Further, in the above-described embodiment, the case where the number of sensors for detecting the leading edge of the plate 1 is three has been described, but the number may be three or more. In this case, as the number of sensors increases, the variation in the writing start position can be further reduced.

Further, in the above-described embodiment, the case where the writing position control device is configured by hardware has been described. However, the capture circuit 14, the arithmetic circuits 15, 16 and the like illustrated in FIG. 1 may be configured by a microcomputer.

Further, the calculation method for obtaining the write start position is not limited to the method in the above embodiment.

(Effects of the Invention) As described above, according to the present invention, a plurality of sensors arranged linearly at intervals in a direction perpendicular to the direction in which the plate is transported are arranged in a direction perpendicular to the direction in which the plate is transported. By detecting that the leading edge on the front side in the transport direction of the plate passes through the transport path at different positions, a detecting operation corresponding to the uneven shape of the leading edge on the forward side in the transport direction of the plate is performed. The average position of the leading edge of the plate is obtained from the average value of the obtained counter values, and the information writing position for the plate is determined from this position. Variations in the printing position of the plate are greatly reduced, and the writing position accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, FIG. 2 is a plan view showing the positional relationship between the plate, sensor and laser beam in this embodiment, FIG. FIG. 5 is an explanatory diagram of the operation in this embodiment, and FIG. 5 is a schematic configuration diagram of a laser plate making machine. In the drawing, 1 is a plate, 4, 4A and 4B are plate feed rollers, 5 is a charging unit, 6 is a laser irradiation unit, 7 is a developing unit, 11 is a pressing roller,
12a to 12c are sensors, 13 is a counter, 14 is a capture circuit, 15 is an average value calculation circuit, 16 is a writing position calculation circuit, and 17 is a writing position setting circuit.

Continuation of the front page (72) Inventor Hideyuki Morita 2-36-9 Maeno-cho, Itabashi-ku, Tokyo Asahi Optical Industry Co., Ltd. (56) References JP-A-63-20961 (JP, A) JP-A-1 JP-A-248165 (JP, A) JP-A-62-74853 (JP, A) JP-A-1-248162 (JP, A) JP-A-59-64450 (JP, A) JP-A-60-55332 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) G03G 15/04-15/04 120 G03G 15/00 510-534 B65H 7/00-7/20 G03G 21/00 370-520 G03G 21 / 14 G03G 13/26

Claims (4)

(57) [Claims] 1. A laser plate making machine in which a charging section, a laser irradiation section, a developing section and a fixing section are arranged along a transport path, and a plate is made by transferring a plate on the transport path. Are arranged at intervals in a straight line in the direction orthogonal to the transport direction of the plate at the location of the transport path on the side, and the leading edge of the forward side in the transport direction of the plate at a different position in the direction orthogonal to the transport direction of the plate. A plurality of sensors that perform a detection operation corresponding to the uneven shape of the leading edge by detecting passage through the transport path location; a counter that counts the transport distance of the plate; and one or more of the sensors Each time the leading edge of the plate is detected, the count value of the counter at the time of detection is fetched, and an average value calculating means for obtaining an average value of the fetched count values corresponding to each sensor, and an average from the average value calculating means value And a writing position calculating means for calculating a writing position based on the information. 3. An information writing position control device for a laser plate making machine, comprising: 2. The writing position calculating means calculates a difference between an average value from the average value calculating means and a current count value of the counter, and calculates a count value by subtracting the difference from a writing position setting value. 2. The information writing position control device for a laser plate making machine according to claim 1, wherein a writing start command is output when the count value ends. 3. An information writing position control device for a laser plate making machine according to claim 1, wherein said counter starts counting from a point in time when any of said sensors first detects the leading edge of said plate. 4. The average value calculating means calculates the count value of a counter at the time of detection each time a sensor that detects the leading edge of the plate after the second one of the sensors detects the leading edge of the plate. 4. The information writing position control device for a laser plate making machine according to claim 3, wherein the information writing position control device is configured to take in the information.