JPH02110424A - Laser exposing method for picture scanning and recording device - Google Patents

Abstract

PURPOSE:To attain exposure and recording with an optimum exposing method in correspondence to picture quality, which is requested to a pattern to be drawn, by arbitrarily selecting the exposing method to execute the exposure and recording with overlapping one part of a multibeam and the exposing method to execute the exposure and recording without overlapping the multibeam. CONSTITUTION:To a cross point data processing circuit 21 and a memory controller 22, a mode designating signal to designate a recording mode is given as a control signal from a picture data preparing part 10. As the recording mode, there are a mode (overlap presence mode) to execute the exposure and recording with overlapping one part of an adjacent beam spot and a mode (overlap absence mode) to execute the exposure and recording with making the respective beam spots adjacent. These exposing methods are switched and selected in correspondence to the picture quality, which is requested to the picture to be recorded, and the exposure and recording is executed. Thus, when the high picture quality is desired to be obtained, the overlap presence mode can be selected and on the other hand, a drawing speed is desired to be preferential rather than the picture quality, the overlap absence mode can be selected.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applicable to a laser exposure method applied to an image scanning recording device such as a laser plotter for manufacturing printed wiring boards, a color scanner for plate making, or a laser printer. In particular, multiple laser recording beams (multibeam)
This invention relates to a laser exposure method for scanning an image recording surface in parallel.

<Prior Art> FIG. 17 is a schematic block diagram of a laser plotter as an example using a conventional laser exposure method.

The laser plotter can be roughly divided into an image data creation section 10;
It is composed of a data converting section 70 and an image recording section 80. The image data creation unit io creates contour side vector data of a figure from CAD data, and includes a minicomputer 11 and a CRT 1 for calculating the vector data.
2, a keyboard 13, and a magnetic tape 14 and a magnetic disk 15 for storing CAD data. The data conversion section 70 converts vector data given from the image data creation section 10 into don't data. The image recording section 80 prints a binary image by scanning the photosensitive material in a band shape while individually controlling the multi-beams 0N10FF based on the plurality of dont data given from the data converting section 70. It is composed of a laser unit 81, a recording cylinder (or a table driven in a plane) 82 which is rotatably driven with a photosensitive material F (image recording surface) pasted thereon, and the like.

In an apparatus that performs simultaneous recording using such multi-beams, the beam spots BS are usually placed adjacent to each other in the axial direction (sub-scanning direction) of the recording cylinder 82, as shown in FIG. array and recording cylinder 82
By rotating the beam spot array, the beam spot array is relatively displaced in the circumferential direction (main scanning direction) of the recording cylinder 82 to perform recording.

By the way, the light intensity distribution of the laser recording beam is not uniform, but has a Gaussian distribution in which the light intensity is extremely reduced at the periphery. When main scanning is performed, the exposure amount is insufficient in adjacent portions of each beam spot, and 412 in that portion is likely to be low, which is a so-called scanning line crack. Further, as shown in FIG. 19, a deterioration in image quality is unavoidable, such as wobbling occurring at the boundary line in the sub-scanning direction of the recorded image.

Therefore, in order to improve the quality of images recorded by multi-beams, adjacent laser recording beams are made to form pairs of orthogonal polarization, as shown in FIG. There is a method in which multiple beam spots BS are scanned by arranging them in a so-called staggered pattern as shown in FIG. A laser exposure method has been proposed. With such overprint exposure, as shown in FIG. 22, there is no scanning line cracking in the recorded image, and smooth border lines can be obtained.

<Problem to be Solved by the Invention> However, according to the laser exposure method described above in which beam spot rows are recorded by superimposing them, for example, when half of the adjacent beam spots BS are overlapped, the beam spot row Compared to a method of recording without overlapping, the image width of the sub-scanning method, which is recorded during one rotation of the recording cylinder, is halved, in other words, the drawing speed is reduced by half.

However, in reality, high image quality is not required for all images to be recorded, and there is also a desire to increase the drawing speed even if some image quality is sacrificed. Considering these requirements, it is inconvenient to expose and record every drawing target using overlapping beam spot arrays.

The present invention has been made in view of the above circumstances, and provides a laser exposure method for an image scanning recording device that allows selecting a laser exposure method according to the image quality required for an image to be recorded. It is intended for deep-frying.

<Means for Solving the Problems> In order to achieve the above object, the present invention has the following configuration.

Particularly, the present invention irradiates an image recording surface with independently controlled multi-beams to form a serial beam spot array, and directs the multi-beams toward the image recording surface in a direction intersecting the spot arrangement direction. In a laser exposure method of an image scanning recording device that performs exposure recording on a recording medium by relative scanning (main scanning) in the direction of spot arrangement and relative scanning (sub-scanning) in the spot arrangement direction, in successive main scanning, A first exposure method in which the multi-beams are sub-scanned so that the latter half of the beam spot row that is main-scanned later fills the space between the beam spots of the first half of the beam spot row that is main-scanned first; In scanning, a second exposure method of sub-scanning the multi-beams so that the last beam spot of the beam spot row to be main-scanned later is adjacent to the first beam spot of the beam spot row to be main-scanned first; The exposure recording is performed by switching and selecting depending on the image quality required for the image to be recorded.

Specifically, there are cases where the multi-beam is composed of an odd number of laser recording beams and cases where it is composed of an even number of laser recording beams. do.

Note that in this specification, the first half of a beam spot row refers to the leading front half of the beam group in the sub-scanning direction in which the beam spots are arranged, and the second half of the beam spot row refers to the rear half of the beam group. beam group.

Effects> According to the present invention, the first exposure method is selected when high image quality is desired, and the second exposure method is selected when priority is given to drawing speed over image quality.

According to the first exposure method, in successive main scans, multiple beam spots are scanned so that the latter half of the beam spot row that is scanned later fills the space between the beam spots of the first half of the beam spot row that is scanned first. Since the beam is sub-scanned, cracks in the scanning line do not occur, and wobbling on the boundary line in the sub-scanning direction is reduced.

According to the second exposure method, in successive main scans, multiple beam spots are scanned so that the last beam spot of the beam spot row that is scanned later is adjacent to the first beam spot of the beam spot row that is scanned first. Since the beam is sub-scanned, a high drawing speed can be obtained.

<Example> Embodiments of the present invention will be described below with reference to the drawings.

Male FF 1 Example The laser exposure method according to this embodiment is a method of exposure recording using a multi-beam consisting of an odd number of laser recording beams, and when the array pitch of the beam spots is P and the number of beam spots is N, When performing exposure recording with high image quality, the multi-beam is sub-scanned at a pitch of approximately (P x N)/2, and when priority is given to writing speed, the multi-beam is sub-scanned at a pitch of approximately P x N. It is something to do.

An example in which the multi-beam is composed of nine laser recording beams will be described below.

FIG. 1 is a schematic diagram of a laser plotter as an example of an image recording apparatus using the exposure method according to the present embodiment.

This laser plotter is composed of an image data creation section 10, a data conversion section 20, and an image recording section 30. Of these, the image data creation section 10 has the same configuration as the conventional device explained in FIG. Therefore, the explanation here will be omitted.

The data converter 20 is configured as follows.

The vector data created by the image data creation unit IO is
The intersection data processing circuit 21 converts the data into intersection data indicating the intersections between the drawing background and each scanning line, and then provides the data to the memory controller 22 . The memory controller 22 is
This is for controlling writing/reading of intersection data to/from the buffer memory circuit 23.

Intersection data processing circuit 21 and memory controller 22
A mode designation signal for designating the recording mode is given as a control signal from the image data creation section 1O.

The recording modes include a mode in which adjacent beam spots are partially overlapped for exposure recording (hereinafter referred to as ``overlapping mode A''), and a mode in which each beam spot is exposed and recorded in a manner that they are adjacent to each other (hereinafter referred to as ``non-overlapping mode A''). (referred to as "mode")
There is.

As shown in FIG. 2, the buffer memory circuit 23 is composed of three buffer memories 23A, 23B, and 23C that are individually controlled by the memory controller 22. Each buffer memory 23A, 23B, 23C
is equipped with nine line memories 1 to 9 corresponding to each laser recording beam of the multi-beam. Each line memory is provided with an area large enough to store the same number of bit data (intersection data) as the number of pixels included in the -scanning line.

The dot data creation circuit 24 includes a buffer memory circuit 23
This is a circuit for converting the intersection point data read from the line memories 1 to 9 into dot data (AND games corresponding to line memories 1 to 9) C1, G2 . . . , C9 and the JK flimp float FF1 . . . connected to each AND gate. FF2.・・・
・It is composed of FF9.

The modulator control circuit 25 individually performs 0N10FF control of the 9-channel acousto-optic modulator provided in the image recording section 30, which will be described later, based on the 9 lines of dot data given from the data creation circuit 24. Outputs a signal for

The image recording section 30 is configured as follows.

As shown in FIG. 3(a), the exposure head 31 provided in the image recording unit 30 includes a frame number beam splitter 33 that splits the laser beam irradiated from the laser light source 32 into nine laser recording beams; Each laser recording beam is individually controlled by the bit data given from the modulator control circuit 25.
It is comprised of a 9-channel acousto-optic modulator (AOM) 34 controlled by N10FF, a reflecting mirror 35, an optical system 36 that focuses a modulated multi-beam and irradiates it onto an image recording surface.

Figures 3 and 3) show a beam spot array of multiple beams obtained by the above-mentioned optical means. The beam spot arrangement pitch P is set to be approximately equal to the beam spot diameter.

Here, in the case of a laser recording beam with a Gaussian distribution, the beam spot diameter is defined as a beam diameter corresponding to a light intensity distribution of 1/e" (approximately 13.5%) with respect to the light intensity at the center of the beam, for example. In other words, the array pitch P of the beam spots is set to a distance at which adjacent laser recording beams do not interfere with each other, and this also applies to the second embodiment described later.

The exposure head 31 is attached to the screw holder 37, and the screw 13
By rotationally driving 7 with a motor 38, the exposing rod 31 is pitch-fed intermittently or continuously in the axial direction of the recording cylinder 40. motor 38
The rotational speed of the motor is controlled by a motor control circuit 39 which receives a speed command pulse from the memory controller 22.

The recording cylinder 40 is driven by a drive mechanism (not shown).
It is rotated at a constant speed, and the rotational speed is detected by a low-return encoder 41. The detection signal of the rotary encoder 41 is given to a timing generation circuit 42. The timing generation circuit 42 creates an output timing signal based on this detection signal and outputs it to the memory controller 22.

Next, the operation of this embodiment will be explained.

First, the writing/reading operation of intersection data to the panzer memory circuit 23 common to each recording mode will be explained, and then the specific operation in the overlap mode and the non-overlap mode will be explained.

Please refer to FIG. The same figure (al is a diagram schematically showing the calculation process of intersection point data, and the same figure (b) is a diagram schematically showing the line memory in the buffer memory 23 in which the calculated intersection data is stored. be.

The intersection data processing circuit 21, which is given the vector data of the drawing pattern from the image data creation unit 10, processes the scanning line (1
), (2), (31,...) and the drawing pattern indicated by the hypotenuse area in the figure. Calculate the Y address of the intersection (white/black change point) and output this as intersection data to the memory controller 22. .Scanning line (1), (21, (3)
The intervals between... are varied depending on the designated recording mode. In this embodiment, the interval between scanning lines in the overlapping mode is set to half that in the non-overlapping mode.

The memory controller 22 (see FIG. 2) takes in the intersection data based on the data request signal (DReq) transmitted from the intersection data processing circuit 21, and stores the data at the corresponding address on the corresponding line memory of the panzer memory circuit 23. The bit data of rll is written to , and a data request acknowledge signal (DReqAck) is output to the intersection data processing circuit 21 . DRe
The intersection data processing circuit 21 that received the qAck signal,
The next intersection data is output together with the DReq signal.

When 1547 minutes of intersection data is output from the intersection data processing circuit 21, the intersection data processing circuit 21 outputs an end signal (
END). The memory controller 22 that received this END13 line feeds the line in the panzer memory circuit 23 and writes to the next line memory. End acknowledge signal (ENDA)
ck) is output.

By receiving this E N D Ack signal, the intersection data processing circuit 21 starts outputting the intersection data of the next line.

Reading of the intersection data from the panzer memory circuit 23 is performed at the following timing. The following description will be made mainly with reference to the fifth leap.

The memory controller 22 receives an output timing signal as shown in FIG. 5(a) from the timing generation circuit 42. One cycle of this output timing signal corresponds to a pixel pitch. The memory controller 22 uses a C3 signal (second
(see figure), and also specifies the line memory address in synchronization with the output timing signal (5th
(See figure (b)).

Then, when the R/W signal shown in FIG. 5(C) is at the rl (J level), the intersection data are read out in order according to the respective designated addresses (see FIG. 5(d)). Reading is performed in parallel for each line memory 1 to 9 within the designated buffer memory.

Each read intersection data is sent to the dot data creation circuit 2.
It is given as one input of the AND gate G (C; 1-G9) of 4. AND gate G is memory controller 2
As a result of opening according to the timing pulse given from 2 (FIG. 5(e)), the next stage JK flip-flop F
Intersection data as shown in FIG. 5(f) is input to F (FFI to FF9).

As a result, the level of the output Q of the JK flip-flop FF switches at each data change point, as shown in FIG. 5 (chain).

That is, the first bit data r13 shown in FIG. 5(d)
However, there is a change point where the drawing pattern changes from white to black,
Next bit data r1. Assuming that a is the point of change from black to white, the rH3 level head range of the Q output of the JK flimp flop FF shown in FIG. ) corresponding to the period. The output Q of each JK flip-flop FF obtained in this way is used as dot data for the next stage's transformer 111W.
s control circuit 25.

While the intersection data is being read from each line memory of the buffer memory circuit 23, the memory controller 22
r□J is input to the line memory as shown in FIG. 5(h). As a result, after the intersection data is read out, the data in that address is rewritten to rQ3 during the rLj level period of the R/W signal shown in FIG. 5(C).

Next, the operation of each recording mode will be specifically explained.

(1) Overlapping mode Hereinafter, with reference to FIG. 6, the operation when the overlapping mode is designated by the operator operating the keyboard 13 of the image data creation unit 10 will be described.

FIG. 6 is an explanatory diagram schematically showing the input/output of line data to the buffer memories 23A, 23B, and 23C.

Here, line data is a general term for intersection data for l scans, and in the figure, ■, ■, ■.

...is shown.

When writing data to the buffer memory circuit 23,
As shown in the first Q(a), first, the buffer memory 23
The contents of line memories 1 to 4 of A are initially cleared to "rO". Among the line data from ■ to ■ sequentially obtained from the intersection data processing circuit 21, odd numbered line data ■ and ■9■.

Write ■, ■ to each line memory of 5.6, 7.8°9 of buffer 1 memory 23A, even numbered line data ■,
■, ■, ■ are written in each line memory of 1°2.3.4 of the buffer memory 23B.

By writing the data as described above, the drawing ratios 6 are completed, and the next line data is written at the same time as the line data is read out and drawn.

That is, as shown in i 6 < (b), while the contents of the line memories 1 to 9 of the buffer memory 23A are being read, the line data [phase], 0 is stored in the line memories 5 to 9 of the buffer memory 23B. .0. ■, ■ are line data ■, 0. in line memories 1 to 4 of the buffer memory 23C.
■ and ■ are written respectively.

When the first main scan is completed, the buffer memory 2 is opened for the second main scan as shown in FIG. 6(C).
Line data ■, ■, ..., @ are read from 3B, and the buffer memories 23C and 23
The next line data is written to A. Thereafter, reading and writing of line data to the buffer memories 23A, 23B, and 23C are similarly performed in parallel (.

Note that each main scan corresponds to one rotation of the recording cylinder 40, and during one rotation of the recording cylinder 40, the exposure head 31 moves approximately 4.5XP (P is the beam spot arrangement In other words, the memory controller 22 outputs a speed command pulse to the motor control circuit 39 so that the multi-beam is sub-scanned at a pitch of approximately 4.5XP.

As a result, as shown in FIG. 7(a), in successive main scans, the latter part of the beam spot row to be main scanned later is located between the beam spots of the first half of the beam spot row to be main scanned first. Exposure recording is performed so as to fill in the area (see FIG. 22). However, in FIG. 7 (al), for ease of understanding, the multi-beams corresponding to each main scan are drawn shifted vertically.

Further, the numbers in FIG. 7 correspond to the line data shown in FIG. 6.

(II) No-overlap mode When the no-overlap mode is specified, the buffer memory 2
3A and 23B are used. First, line data t of ■ to ■ output from the intersection data processing circuit 21 are stored in line memories 1 to 9 of the buffer memory 23A. While drawing is started and the line data ■ to ■ in the buffer memory 23A are being read out in parallel, the next line data [phase] to [phase] are stored in the line memories 1 to 9 of the buffer memory 23B. written. Then, while line data [phase] to {circle around (2)} are being read out from the buffer memory 23B, line data necessary for the next main scan is written into the buffer memory 23A. Thereafter, writing and reading of line data to and from the buffer memories 23A and 23B are performed simultaneously (.

On the other hand, the memory controller 22 includes a motor control circuit 39
The number of speed command pulses given per unit time to the recording cylinder 40 is doubled as compared to the non-overlap mode.
Control is performed so that the exposure radar 31 advances by about 9XP during one rotation of the multi-beam, in other words, the multi-beam is sub-scanned at a pitch of about 9XP.

As a result, as shown in FIG. 7(b), in successive main scans, the last beam spot of the beam spot row to be main scanned later is the first beam spot of the beam spot row to be main scanned first. Exposures are recorded next to each other (
(See FIG. 19), the drawing speed at this time is twice that of the overlapping mode.

The laser exposure method according to this embodiment is a method of exposure recording using a multi-beam consisting of an even number of recording beams, and the array pitch of the beam spots is set to P1, the number of beam spots is N. In this case, in the overlapping mode, the distance between the centers of adjacent beam spots in the divided portion is approximately 1.5XP.
The multi-beam is divided into a first half and a second half each consisting of the same number of beam groups, and these beam groups are sub-scanned at a pitch of approximately (P×N)/2. In the non-overlapping mode, the front Sub-scanning is performed at a pitch of approximately P×N with the beam spot rows of the latter beam group being arranged adjacent to each other in series.

Hereinafter, a case will be described using as an example a case where the multi-beam is composed of 10 laser recording beams.

Since the schematic structure of the device is almost the same as that of the first embodiment shown in FIG. 1, illustration is omitted, and only the parts different from the first embodiment will be explained here.

In this embodiment, since 10 laser recording beams are used, the buffer memories 23A, 23B, 23C
are each equipped with 10 line memories, and correspondingly, the dot data creation circuit 24 is equipped with 10 AND gates and 10 JK flip-flops.

In addition, in the overlapping mode, each multi-beam is
In order to divide the beam into individual beam groups, the exposure head 31 is constructed as shown in FIG.

A laser beam Bl emitted from a laser light source 32 is split into two laser beams B2 and B3 by a beam splitter 51. One laser beam B2 is reflected by a reflection mirror 52 and then divided into five laser recording beams by a plurality of beam division H53. The divided beam group B4 is individually 0N10FFIII by the acousto-optic modulator 54.
be controlled. Beam group B emitted from the acousto-optic modulator 54
5 is reflected by a reflecting mirror 55 and incident on a polarizing beam splitter 56.

On the other hand, the other laser beam B3 split by the beam splitter 51 is reflected by reflection mirrors 57 and 58, so that the plane of polarization is displaced by 90 degrees, and then the multiple beam splitter 59 records five laser beams. divided into beams. The divided beam group B6 is individually 0N10FFi! by the acousto-optic modulator 60. il + controlled. The beam group B7 emitted from the acousto-optic modulator 60 is reflected by a reflecting mirror 61, and then enters the polarizing beam splitter 56 via a beam shifter 62.

The beam shifter 62 is composed of a transparent parallel plane plate as shown in FIG. The emitted light can be shifted parallel to the incident light by a distance L (in this case, P/2).

L = m ・ (1-cos θ /, r--
〒i-hoo-s-ding)71r下子r)-sin θwhere, t is the thickness of the parallel plane plate, and n is its refractive index.

Therefore, as shown in No. 101M, by rotating the beam shifter 62 by a predetermined angle θ using a rotatable actuator 63 such as a rotary solenoid or a pulse motor (see FIG. 8), the incident beam group B7 is
It can be emitted as a beam group B7' displaced by /2.

FIG. 11 (al) shows the arrangement of beam spot arrays of multi-beams obtained when the rotation angle θ of the beam shifter 62 is set to approximately zero degrees. This multi-beam is used in the non-overlap mode, which will be described later.

On the other hand, in FIG. 11(b), the beam shifter 2 is set at a predetermined angle θ.
This shows the arrangement of the multi-beam beam spot rows obtained when the setting is set to . This multi-beam is used in the overlapping mode, which will be described later. As shown in FIG. 11(b), by displacing the incident beam group B7 by P/2 in the sub-scanning direction, adjacent beam groups B5. B
The distance between the centers of the nearest beam spots of 7' is approximately 1.
It becomes 5XP.

Note that in the eighth session, two beam groups 85. By making each polarization plane of B7 orthogonal,
The light amount loss in the polarizing beam splitter 56 is reduced. However, if the loss of light ff1tJ4 is acceptable, a normal beam splitter may be used.
In this case, there is no need to provide a reflecting mirror 57 or the like for orthogonally displacing the plane of polarization.

FIG. 12 is a perspective view showing the main parts of another configuration example of the exposure head 31.

In FIG. 8, one beam group B7 is shifted by half a pitch by changing the angle of the beam shifter 62, but in this example, the reflecting mirror 55 is moved to the guide rail 64.
The reflective mirror 55 is configured to be slidable along the reflecting mirror 55, and is configured to be driven by an actuator 65 capable of reciprocating, such as a push-pull solenoid. According to this example, by moving the reflecting mirror 55 by a half pitch of the beam spot row, the beam group B5 can be displaced by a half pitch.

Next, referring to FIG. 2, each buffer memory 23A, 2
The input/output of line data to 3B and 23C will be explained.

(1) When the overlap mode is specified, the mode designation signal is transmitted to the intersection data processing circuit 21 and the memory controller 2.
2 and the exposure radar 31, the beam shifter 62 explained in FIG.
(Or the reflecting mirror 55 explained in No. 121m)
) is driven, and the array state of the beam spot row is the 11th
The state shown in Figure (b) is reached.

In the overlapping mode, buffer memories 23A, 23B, and 23C are used as in the first embodiment. The procedure for writing/reading line data into each buffer memory is performed in the same manner as in the first embodiment, so the order is shown in FIG. 13 and the explanation here will be omitted. In addition, Fig. 13(a)
indicates the initial data acquisition, and Figure 13), (C
) and (d) schematically show the read and write states of line data in the first, second, and third main scans.

In addition, in the overlapping mode, the memory controller 22 controls the movement amount of the exposure head 31 per one revolution of the recording cylinder 40, that is, the sub-scanning pitch, to be approximately 5XP.
A speed command pulse is output from the motor control circuit 39 to the motor control circuit 39.

As a result, as shown in FIG. 14(a), in successive main scans, the latter half of the beam spot row that is scanned later is replaced by the beam spot of the first half of the beam spot row that is scanned first. Exposure recording is performed to fill in the gaps (see Figure 22). In Figure 14 (a), for ease of understanding, the multi-beams corresponding to each main scan are mounted vertically shifted. The numbers in the figure correspond to the line data shown in FIG.

(II) Operation in non-overlapping mode When the non-overlapping mode is specified, the beam shifter 62 (
Alternatively, the reflecting mirror 55) is driven to return to its original position. As a result, the beam spot row is
As shown in Figure 1 (al), the divided beam group B5.
B7 are placed next to each other in series.

Then, as in the non-overlap mode of the first embodiment, the line data of ■~[phase] are written to the buffer memory 23A, and while these line data are being read, the line data of ■~[phase] are written to the buffer memory 23B. After that, line data is written to and read from the buffer memories 23A and 23B at the same time.

Further, as described in the first embodiment, the number of speed command pulses is set to twice that in the overlapping mode, so that the sub-scanning pitch of the multi-beam becomes approximately 10XP.

As a result, as shown in FIG. 14(b), in successive main scans, the last beam spot of the beam spot row to be main scanned later is the first beam spot of the beam spot row to be main scanned first. Exposure recording is performed so that they are adjacent to each other (see FIG. 19), and the drawing speed at this time is twice that of the overlapping mode.

Note that the present invention can also be modified as follows.

(1) In the first embodiment, a multi-beam consisting of nine laser recording beams is used, and in the second embodiment, a multi-beam consisting of ten laser recording beams is used to perform exposure recording. It goes without saying that the number of laser recording beams constituting a multi-beam in the present invention is not limited.

(2) In each of the above-described embodiments, the number of laser recording beams constituting the multi-beam in the non-overlapping mode, that is, the number of beam spots, was set to be the same as that in the overlapping mode, but this is not necessarily the case in the present invention. but not limited to.

That is, in the case of the first embodiment, if the number of beam spots in the overlapping mode is an odd number, the number of beam spots in the non-overlapping mode is arbitrary, and the number of beam spots in the non-overlapping mode is The number of beam spots may be set to an odd number different from the number of beam spots in the presence mode, or may be set to an even number. For example, the first embodiment can be modified as follows.

Commercially available multiple beam splitters and acousto-optic modulators (A
OM) is typically an even number of channels (eg, 10 channels). In this case, in the overlapping mode, it is necessary to record with an odd number of laser recording beams, so the AOM
9 with one of the channels at the end always in the OFF state.
If you record with one laser recording beam, and on the other hand, in non-overlap mode, use all channels of the AOM and record with 10 laser recording beams, the recording speed in non-overlap mode can be reduced by the first implementation described above. It can be made faster than the example. In this case, the number of speed designation pulses given to the sub-scan feed motor control circuit 39 shown in FIG.
)/2 and PXIO in non-overlapping mode. In addition, the buffer memory 23 etc. each have 10
Needless to say, use one from Channel.

Similarly, regarding the second embodiment, if the number of beam spots in the overlapping mode is an even number, the number of beam spots in the non-overlapping mode is arbitrary, and the number of beam spots in the non-overlapping mode is , may be set to an even number different from the number of beam spots in the overlapping mode, or may be set to an odd number. For example, if the configuration is configured so that recording can be performed with a maximum of 11 laser recording beams, recording will be performed with 10 laser recording beams in overlapping mode, and recording will be performed with 11 laser recording beams in non-overlapping mode. You can also do this.

(3) In addition, the number of laser recording beams that make up a multi-beam does not necessarily need to be constant; the number (number of channels) can be specified arbitrarily depending on the complexity of the pattern to be drawn. may be configured. If you do this, for example, the pattern to be drawn is complex and it takes a long time to calculate vector data.
In cases where there is a possibility that data cannot be transmitted in real time from the image data creation section 10 to the data change section 20, the time required for data creation and the writing time can be reduced by reducing the number of laser recording beams and slowing down the writing speed. You can take munching with.

Specifically, when applied to the first embodiment, in the overlapping mode, the number of channels can be switched and specified to any of 9.7.5.3 (or some number of these). , in non-overlapping mode, increase the number of channels from 9 to
It is also possible to configure it so that it can be switched to any number up to 2 (or some of these numbers). In this case, the number of speed designation pulses given to the motor control circuit 39 may be varied in conjunction with switching the number of channels.

On the other hand, in the case of the second embodiment, the number of channels can be changed as follows. For example, in overlapping mode,
The number of channels can be switched to 10.8, 6, 4°2 (or some number of these). In this case, depending on the number of channels, the same number of beam spots may be selected from the center of the two beam groups, as indicated by diagonal lines in Fig. 15 (al to (e)). The configuration is such that the number can be switched to any number from 10 to 2 (or some of these numbers), and the front and rear beam groups are placed next to each other. The number of speed designation pulses given to the motor control circuit 39 may be varied in conjunction with switching the number of channels.

However, the maximum number of channels is 10 channels,
When recording in the non-overlapping mode with 5 channels or less, one beam group is shifted by displacing the beam shifter 62 shown in Part 8 or the reflecting mirror 55 shown in Fig. 12, so that the front and rear halves are It is not necessarily necessary to adopt the method of arranging the beam spot groups of 2 adjacent to each other. For example, when performing the non-overlap mode with 4 channels, the 16th
As shown in the figure, recording may be performed using adjacent beam spots B5l-B54 in one beam group.

(4) As can be understood from the above explanation, the number of channels of the laser recording beam that makes up the multi-beam is set appropriately depending on the complexity of the image to be exposed, and there are two modes: overlap mode and non-overlap mode. The mode is appropriately set depending on the required image quality. Therefore, whether or not the beam spots overlap is completely unrelated to the number of beam spots, and can be set independently.

For example, the first method records the overlapping mode using an odd number of laser recording beams as in the first embodiment, and the overlapping mode uses an even number of laser recording beams as in the second embodiment. If the method is the second method, these methods can be used depending on the complexity of the image to be drawn and the required quality, for example, as shown in the table below.
CH) can be switched. In this example, it is assumed that the number of channels can be arbitrarily selected up to a maximum of 10 channels.

(Hereinafter, blank space) (5) Furthermore, in the above embodiment, a laser plotter was used as an example, but the present invention can also be applied to other image scanning and recording devices such as a color scanner for plate making and a laser printer. can.

(6) Furthermore, in the above embodiment, the recording cylinder 40 is used to make the image recording surface a curved surface, but a table driven in a plane may be used to make the image recording surface a flat surface.

<Effects of the Invention> As is clear from the above description, according to the present invention, it is possible to arbitrarily select an exposure method in which a portion of the multi-beams are overlapped for exposure recording and an exposure method in which exposure recording is performed without overlapping. Since the present invention is constructed in such a manner that exposure recording can be performed using the optimum exposure method according to the image quality required for the pattern to be drawn, it is extremely practical.

[Brief explanation of drawings]

1 to 7 are explanatory diagrams of the first embodiment of the present invention,
Figure 1 is a schematic block diagram of the laser plotter, Figure 2 is a detailed block diagram around the buffer memory circuit, and Figure 3 (a).
3 is a perspective view showing an example of the configuration of an exposure head, FIG. 3 is an explanatory diagram of the arrangement state of beam spots, FIG. 4 is an explanatory diagram of the operation of writing intersection data to the line memory, and FIG. 6 is an explanatory diagram of the writing/reading operation of line data to the buffer memory in the overlapping mode. FIG. 7 is an explanatory diagram of the multi-beam scanning state. , FIG. 7(a) shows the overlapping mode, and FIG. 7(b) shows the non-overlapping mode. FIGS. 8 to 14 are explanatory diagrams of the second embodiment of the present invention. The figure is a perspective view showing an example of the configuration of the exposure head, FIG. 9 and FIG. 1O are explanatory diagrams of the beam shifter, FIG. The figure is a perspective view of main parts of another configuration example of the exposure head, and FIG.
FIG. 14 is an explanatory diagram of the readout operation, and FIG. 14 is an explanatory diagram of the scanning state of the multi-beams. FIG. 14(a) shows the overlapping mode, and FIG. 14(b) shows the non-overlapping mode. Figures 15 and 16 are explanatory diagrams of a modification of the second embodiment. Figure 15 is an explanatory diagram of switching the number of channels in overlapping mode, and Figure 16 is an explanatory diagram of channel settings in non-overlapping mode. It is an explanatory diagram. 17 to 22 are explanatory diagrams of a conventional example, and FIG. 17 is a schematic block diagram of a laser plotter according to the conventional example.
Figure 8 is an explanatory diagram of a general array of non-overlapping beam spot arrays, Figure 19 is an explanatory diagram of an example of a recorded image exposed by non-overlapping beam spots, and Figure 20 is an explanatory diagram of an array of overlapping beam spot arrays. FIG. 21 is an explanatory diagram of a beam spot array arranged in a staggered manner, and FIG. 22 shows an example of a recorded image exposed by an overlapping beam spot array. lO...Image data creation unit 20...Data changing unit 21...Intersection data processing circuit 22...Memory controller 23...Banofa memory circuits 23A, 23B, 23C...Buffer memory 24...
・Dot data creation circuit 25...Modulator control circuit 30...Image recording unit 31...Exposure head 40...Recording cylinder Applicant Dainippon Screen Mfg. Co., Ltd. Agent Patent attorney Tsutomu Sugitani η Figure 1゜Figure 1] Figure 15 Figure 16 Figure 18 Figure 19

Claims (9)

[Claims] (1) Multiple independently controlled laser recording beams (hereinafter referred to as multi-beams) are irradiated onto the image recording surface to form a series of beam spots, and the multi-beam beams are directed onto the image recording surface. An image that is exposed and recorded on a recording medium by performing relative scanning (hereinafter referred to as main scanning) in a direction crossing the spot arrangement direction and relative scanning (hereinafter referred to as sub-scanning) in the spot arrangement direction. In a laser exposure method for a scanning recording device, in successive main scans, the latter part of the beam spot row that is main scanned later fills the space between the beam spots of the first half of the beam spot row that is main scanned first. A first exposure method in which multi-beams are sub-scanned, and in successive main scans, the last beam spot of the beam spot row that is main-scanned later is adjacent to the first beam spot of the beam spot row that is main-scanned first. A laser exposure method for an image scanning and recording apparatus that performs exposure recording by switching and selecting a second exposure method of sub-scanning a multi-beam according to the image quality required for the image to be recorded. (2) In the laser exposure method for an image scanning recording device according to claim (1), in the first exposure method, the multibeam is an odd number of laser recording beams, and the arrangement pitch of the beam spots of the multibeam is P, When the number of beam spots is N, approximately (
The second exposure method sub-scans the multi-beam at a pitch of P x N)/2, and the second exposure method is approximately P x A laser exposure method for an image scanning recording device that performs sub-scanning with a multi-beam at a pitch of M. (3) In the laser exposure method for an image scanning recording device according to claim (2), the number M of beam spots in the second exposure method is the same as the number N of beam spots in the first exposure method. Laser exposure method for recording equipment. (4) In the laser exposure method for an image scanning recording device according to claim (2), the number M of beam spots in the second exposure method is an odd number different from the number N of beam spots in the first exposure method. Laser exposure method for image scanning recording device. (5) The laser exposure method for an image scanning and recording apparatus according to claim (2), wherein the number M of beam spots in the second exposure method is an even number. (6) In the laser exposure method for an image scanning recording device according to claim (1), in the first exposure method, the multi-beam is an even number of laser recording beams, and the array pitch of the beam spots of the multi-beam is P, When the number of beam spots is N, the distance between the centers of adjacent beam spots in the divided portion is approximately 1.5×
The multi-beam is divided into a first half and a second half each consisting of the same number of beam groups so that P, and these beam groups are sub-scanned at a pitch of approximately (P×N)/2. The second exposure method is to perform sub-scanning at a pitch of approximately P×N with the beam spot array pitch of the multi-beam being P and the number of beam spots being M, with the beam spot arrays being arranged next to each other in series. Laser exposure method for image scanning recording device. (7) In the laser exposure method for an image scanning recording device according to claim (6), the number M of beam spots in the second exposure method is the same as the number N of beam spots in the first exposure method. Laser exposure method for recording equipment. (8) In the laser exposure method for an image scanning recording device according to claim (6), the number M of beam spots in the second exposure method is an even number different from the number N of beam spots in the first exposure method. Laser exposure method for image scanning recording device. (9) The laser exposure method for an image scanning and recording apparatus according to claim (6), wherein the number M of beam spots in the second exposure method is an odd number.