JP2636984B2 - Image connection method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image connecting method and apparatus for drawing and recording a large-size image by connecting small-size divided images in a flat-scanning image recording apparatus.

[0002]

2. Description of the Related Art As is well known, a plane scanning type image recording apparatus performs a main scanning of a light beam modulated by an image signal by a light beam deflector such as a polygon mirror.
A desired image is printed by irradiating the photosensitive material placed on the table which is fed in the sub-scanning direction.

In the case of drawing and recording an image using such a flat-scanning image recording apparatus, if the recorded image is too large, both sides of the recorded image are affected by the so-called tilting of the polygon mirror and aberration of the optical system. In this case, the main scanning of the light beam is not performed at the same pitch, and the light beam cannot be sufficiently stopped down.

Accordingly, for example, Japanese Patent Application Laid-Open No. 63-129620
As disclosed in Japanese Unexamined Patent Application Publication No. H10-115, a method of dividing a large-sized image into a plurality of small-sized images and printing each divided image intermittently in a main scanning direction on a photosensitive material intermittently is used. Have been.

[0005]

However, in connecting divided images, it is unavoidable that slight overlap or deviation of images occurs at the boundary between adjacent divided images due to limitations in accuracy of the image recording apparatus. . If the recorded image is a pattern used in the manufacture of electronic components such as printed wiring, there is no inconvenience if the amount of deviation is within the specified value, but if the recorded image is used for printing, especially when the divided image is used. When the boundary is in the halftone area of the halftone dot,
Even if the deviation amount is small, the boundary between the divided images becomes conspicuous as unevenness on the printed matter, which causes a disadvantage that the quality of the printed matter is reduced.

The present invention has been made in view of such circumstances, and when drawing a large-sized image by connecting small-sized divided images, the boundary between adjacent divided images is made inconspicuous. It is another object of the present invention to provide an image connection method and apparatus capable of improving the quality of a printed matter.

[0007]

The present invention has the following configuration in order to achieve the above object. That is, according to the first aspect of the present invention, a large-size image is divided into small-size images, and each divided image is connected at least in the main scanning direction to print a large-size image on a photosensitive material. In the image connection method in the image recording apparatus of the first aspect, an edge of the first main scanning for drawing one of the divided images on the same scanning line is provided so that the divided images adjacent in the main scanning direction each have an overlapping area. Scanning is performed so that the end of the second main scan for drawing the other divided image overlaps, and in the first main scan in the overlap region, the second main scan is appropriately selected from the image data of the overlap region. One image element group, and the second
In the main scanning, the second image element group not selected in the first main scanning is drawn, and the two image element groups are drawn so as to be mixed in the overlapping area.

According to a second aspect of the present invention, a large-sized image is divided into small-sized images, and each divided image is connected at least in the main scanning direction, and the large-sized image is printed on a photosensitive material. In an image connection device in a plane scanning type image recording apparatus, a first storage means for storing image data of an original, and a second storage means for storing mask data of an overlapping area between divided images adjacent in the main scanning direction. And light for scanning such that an end of a first main scan for drawing one divided image and an end of a second main scan for drawing the other divided image on the same scanning line overlap with each other. When drawing an overlapping area by the beam scanning means and the first main scanning, the logical product of the image data read from the first storage means and the mask data read from the second storage means is taken. The overlap area is selectively drawn by giving data obtained based on the light beam scanning means to the light beam scanning means, and when the overlap area is drawn by the second main scanning, the image read out from the first storage means is used. Data obtained based on the logical product of the inverted mask data obtained by inverting the mask data read from the second storage means is given to the light beam scanning means to selectively overlap regions. Image data masking means for drawing.

[0009]

The operation of the present invention is as follows. That is,
According to the method of the first aspect, in the overlapping area of the divided image, the first main scan draws the first image element group appropriately selected from the image data of the overlapping area,
In the second main scan, the second not selected in the first main scan
And the two image element groups are mixed so that even if there is some deviation between the first main scan and the second main scan, the joint of the divided images Becomes less noticeable.

According to the second aspect of the present invention, in the overlapping area of the divided images, in the first main scan, the image data read from the first storage means and the image data read from the second storage means. AND with the mask data
The overlapping area is selectively drawn. Also, in the second main scan, the image data and the inverted mask data obtained by inverting the mask data are logically ANDed, so that the image data not selected in the first main scan is drawn in the overlapping area.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. A. Principle of the Method of the Present Invention Before describing the specific embodiment apparatus, the principle of the method of the present invention will first be described with reference to FIGS. In FIG. 1, reference symbol P denotes a photosensitive material, A and B denote adjacent divided images in the main scanning direction, and C denotes a region where both divided images A and B are positively overlapped. The divided image A is along the main scanning line MS1, and the divided image B is the main scanning line MS2.
Are drawn line-sequentially. Ideally, the main scanning lines MS1 and MS2 are originally on the same scanning line. However, it is assumed that the main scanning lines MS1 and MS2 have a slight deviation in the sub-scanning direction or the main scanning direction due to the limit of the accuracy of the apparatus.

The main scanning line MS1 in the overlapping area C
Then, the first image element group appropriately selected from the image data of the overlapping area C is drawn, and the second main scanning line MS2 in the overlapping area C is used for the main scanning line MS1.
The second image element group which is not selected is drawn, and the two image element groups are drawn so as to be mixed in the overlapping area C.

The manner in which the two image element groups are mixed in the overlapping area C is not particularly limited. However, when the main scanning lines MS1 and MS2 are shifted in the sub-scanning direction, for example, as shown in FIG. Main scan lines MS1 and MS2
May be configured such that each of the image element groups of both main scanning lines MS1 and MS2 is randomly mixed as shown in FIG. The image element groups may be composed in a stepwise manner, as shown in FIG.

In FIGS. 2A to 2C, the mixed pattern of the image element groups is the same for each main scanning line. However, the mixed pattern may be changed for each main scanning line.
When a color image is drawn, the mixed pattern of the image element groups of the yellow (Y), magenta (M), cyan (C), and black (K) planes is changed to change the boundary of the divided image. It is possible for the parts to be less noticeable.
The image elements of the divided images to be mixed may be in units of dots or in units of halftone dots. When the main scanning lines MS1 and MS2 are shifted in the main scanning direction, as shown in FIG.
By changing the selection boundary position of each image element of MS2, for example, at random, both scan lines MS1, MS2
May be configured so that each of the image element groups is mixed.

B. First Embodiment Next, an embodiment of an image connecting apparatus using the method of the present invention will be described. FIG. 3 is an external perspective view showing an example of a flat-scanning image recording apparatus. In the figure, reference numeral 1 denotes a movable table on which the photosensitive material P is placed. The movable table 1 is slidably mounted on a pair of guide rails 3 arranged side by side on the fixed table 2, and a ball screw 4 screwed to the movable table 1 is driven by a Y-axis drive motor 5, Y
Sub-scan feed is performed in the axial direction. An exposure head 6 is provided above the movable table 1. The exposure head 6 is provided with an optical system for scanning a laser beam in the main scanning direction along the X axis, as described later. A gate-shaped frame 7 is erected on the fixed table 2.
The exposure head 6 is slidably mounted on a pair of guide rails 8 juxtaposed on the upper surface of the exposure head. Exposure head 6
, The ball screw 9 screwed to the X-axis drive motor 1
By driving at 0, it is configured to move in the X-axis direction.

In the present invention, the table 1 on which the photosensitive material is placed and the exposure head 6 are relatively positioned on the X axis and the Y axis.
Since it is only necessary to be able to move along the axis, the exposure head 6 may be fixed, and the table 1 may be configured to be movable along the X axis and the Y axis. Conversely, the table 1 may be fixed and the exposure head 6 may be configured to be movable along the X axis and the Y axis.

Next, the configuration of the optical scanning system provided in the exposure head 6 of this embodiment will be described with reference to FIG. In the figure, reference numeral 11 denotes He-Ne for irradiating the laser beam LB.
It is a gas laser light source such as a laser. The laser beam LB emitted from the laser light source 11 is applied to an acousto-optic light modulator (AO
M). The AOM 12 turns on the laser beam LB via the AOM driver 13 based on serial image data provided from an image processing unit 20 described later.
/ OFF modulation. The modulated laser beam LB is main-scanned in the X direction by the polygon mirror 14 that is driven to rotate, and is irradiated on the photosensitive material P via the fθ lens 15. Reference numeral 16 in the figure denotes a synchronization sensor for detecting the main scanning start timing when the laser beam LB is incident. The synchronization signal output from the synchronization sensor 16 is given to the image processing unit 20.

The optical scanning system applied to the present invention is not limited to the one described above. For example, when a semiconductor laser is used as a laser light source, a separate light beam modulator such as AOM is not required. Further, as a means for main scanning with the laser beam LB, a galvanomirror or an acousto-optic light deflector can be used.

Next, the configuration of the above-described image processing section 20 will be described with reference to FIG. In the figure, reference numeral 21 denotes a RAM as first storage means for storing image data of a document developed into a bit map. The RAM 21 includes an address area for storing a plurality of bits (for example, 8 bits or 16 bits) of image data as one unit (hereinafter, referred to as a word). Each address area is specified by specifying an address in the X direction and the Y direction. Be called. Reference numeral 22 denotes a ROM as second storage means in which mask data of the overlapping area C of the divided images A and B has been written in advance. The mask data is obtained by converting the image data of the overlapping area C into one on the same scanning line.
This is bit data for selecting so as to be complementary in the first main scan and the second main scan. This mask data is also stored in word units similarly to the above-described image data, and is read out by specifying each address in the X and Y directions.

The counter 23X includes a RAM 21 and an RO.
When addressing the M22 in the X direction, the counter 23Y
For addressing the AM 21 and the ROM 22 in the Y direction,
Used respectively. The subtracter 24 is used to specify an address in the X direction unique to the ROM 22. The address setting units 25a to 25d sequentially output the drawing end address in the X direction (X _{EA in} FIG. 4), the end address of the overlap area C (O _{EA in} FIG. 4), and the start address of the overlap area C (FIG. 4).
O _SA), drawing end address in the Y-axis direction (in FIG. 4 of Y in
_EA ), for example, a digital switch.

Each of the comparators 26a to 26d has a counter 23
X or the count value of the counter 23Y is the address setter 2
Each of the detection signals is provided to the controller 27 for detecting whether or not the values match the set values of 5a to 25d. The controller 27 controls the counters 23X and 23Y based on the detection signals of the comparators 26a to 26d,
The control of the AM 21 and the ROM 22 is performed.

In addition to the components described above, the image processing unit 20
Are registers 28a and 28b for converting word-based parallel image data read from the RAM 21 or the ROM 22 into serial image data, and gate circuits G1 to G3.
And a latch circuit 29. The synchronization signal of the synchronization sensor 16 shown in FIG. 4 is given to the controller 27, and the serial image data output from the latch circuit 29 is
Are provided to the AOM driver 13 shown in FIG.

The operation of the first embodiment will now be described. Writing of image data to the RAM 21 is performed as follows. First, R is controlled by the controller 27.
After setting the AM 21 to the writable state, the counter 23X is sequentially incremented from “0”, and RA
Image data is written in the X direction on line 0 of M21. When the count value of the counter 23X reaches drawing end address X _EA in the X direction, on the basis of the coincidence detection signal of the comparator 26a, together with the controller 27 clears the counters 23X, the counter 23Y from "0" to "1" Increment. Then, similarly to the above, the counter 23X is sequentially incremented, and the image data is written in the first row of the RAM 21. The above write operation is performed when the count value of the counter 23Y is the drawing end address Y _{EA in the} Y direction, and the count value of the counter 23X is the drawing end address X _{EA in the} X direction.
, The writing of all the image data to the RAM 21 is completed. After writing the image data, each of the counters 23X and 23Y is cleared.

Next, the reading of each data from the RAM 21 and the ROM 22 and the drawing operation will be described. In the present embodiment, the divided image A and the overlap area C are selected on the photosensitive material P by the first main scan in a line-sequential manner over a required number of main scan lines (hereinafter simply referred to as “first main scan”). The printed dot group is printed.
As described above, the main scanning of the light beam is performed by rotating the polygon mirror 14 shown in FIG. 4, and the sub-scanning is performed by feeding the movable table 1 in the Y direction shown in FIG. When the first main scan is completed, the movable table 1 is returned to the original position and the exposure head 6
Are step-advanced in the X direction, and a line-sequential second main scan (hereinafter simply referred to as “2”) over the required number of main scan lines
A second main scan ”) prints the divided image B and the remaining dot group in the overlapping area C on the photosensitive material P.

The first data reading is performed as follows. First, the controller 27 determines whether the RAM 21 and the R
After setting the OM 22 to the readable state, the value of the counter 23X is incremented in order from “0” based on the synchronization signal from the synchronization sensor 16. As a result, the image data of the 0th row in the RAM 21 is read out in word units and serially converted by the register 28a.
It is sequentially applied to the gate circuit G3.

At the time of the first data read, the controller 27 applies "H" to the gate circuits G1 and G2.
A level selection (SEL) signal is output. Further, the count value of the counter 23X overlaps the start address O of the overlap area C.
Until _SA is reached, the controller 27 controls the gate circuit G
1 and G2, enable at “L” level (EN
B) A signal is issued. As a result, the gate circuits G1, G
2 output "H" level, so that gate circuit G3
Is released, the serial image data output from the register 28a is supplied to the AOM driver 13 via the gate circuit G3 and the latch circuit 29, and the image in the 0th row of the divided area A is printed on the photosensitive material.

[0027] count value of the counter 23X reaches the start address O _SA overlap area C, on the basis of the coincidence detection signal from the comparator 26c, the controller 27 outputs the ENB signal of "H" level. On the other hand, a subtractor 24 for subtracting an address O _SA from the count value of the counter 23X, by the output value incrementing sequentially from "0" from that point, the mask data in the ROM22 is read in words To go. As an example of the address specification of the ROM 22, the drawing start address in the X direction is “0000” in hexadecimal and the drawing end address is “FFFF”.
"7F00" the start address O _SA region C overlap, when the end address O _EA overlap area C is "80FF",
9-bit addresses up to "1FF" (80FF-7F00) are given to the ROM 22 as lower addresses (X-direction addresses). As the upper address (Y direction address), the value of the counter 23Y is input. RO
It is not always necessary to write data in M22 in all directions in the Y direction. For example, data specified by an upper address of 8 bits may be written, and mask data of the same pattern may be repeatedly read every 256 lines.

The mask data in word units read from the ROM 22 is serial-converted by the register 28b and then applied to the gate circuits G1 and G2. Each of these gate circuits G1 and G2 has a SEL of “H” level.
Since the signal and the ENB signal are input, the register 28b
Is output to the gate circuit G3 via the gate circuit G1. Now, assuming that the read word-unit mask data is “10101010”, the logical product of this mask data and the image data of the 0th row in the overlapping area C is obtained, and as a result, the first, third, and fifth data are obtained. , The seventh image (dot) data passes through the gate circuit G3 and is supplied to the AOM driver 13 via the latch circuit 29, so that one dot-unit image is displayed in the overlapping area C.
It is baked every other.

When the count value of the counter 23X reaches the end address O _EA of the overlap area C, the controller 27 returns the ENB signal to "L" level and clears the counter 23X based on the coincidence detection signal of the comparator 26c. Then, the count value of the counter 23Y is incremented from "0" to "1". Thereafter, the counter 23 is operated in the same manner as described above.
By sequentially incrementing X, the image data of the first row of the divided area A and the overlapping area C is stored in the RAM 2
1, the printing of the dots in the first row of the divided area A and the selective printing of the dots in the first row of the overlapping area C are performed.

The above operation is performed until the count value of the counter 23Y reaches the drawing end address Y _{EA in the} Y direction and the address of the counter 23X reaches the end address O _EA of the overlapping area C, thereby _achieving the first main scanning. Baking is completed.

[0031] When the first main scanning is completed, the controller 27 switches the SEL signal to the "L" level, the start address O _SA region C overlaps with the counter 23X
Is set as an initial value, and the counter 23Y is cleared.
By the count value of the counter 23X is gradually incremented in order from the "O _SA", the image data of the 0 line of the region C overlaps the RAM21 is read out in units of words, the gate circuit G3 via the register 28a Given. In parallel with the reading of the image data from the RAM 21, the mask data in the 0th row is read from the ROM 22 in word units. Since the ENB signal is at the “H” level and the SEL signal is at the “L” level during the reading of the image data of the overlap area C, the gate circuit G1 outputs the “H” level, and the gate circuit G2 Outputs data (inverted mask data) obtained by inverting the mask data supplied from the register 28b. For example, register 2
8b is "1010101"
0 ", the gate circuit G3 takes the logical product of the inverted mask data" 01010101 "and the image data in the 0th row of the overlapping area C, and as a result, the second, fourth, sixth, and
The eighth image data passes through the gate circuit G3 and is supplied to the AOM driver 13 via the latch circuit 29, so that one dot-unit image of the overlapping area C not selected in the first main scan is output. It will be burned everywhere.

When the count value of the counter 23X reaches the end address O _EA of the overlapping area C, the ENB signal is switched to the "L" level, and thereafter the image data of the divided area B of the RAM 21 is not masked without being masked. Circuit G3
And to the AOM driver 13 via the latch circuit 29.

[0033] When the count value of the counter 23X has reached the drawing end address X _EA in the X direction in the second main scan, based on the coincidence detection signal of the comparator 26a, the controller 27
Clears the counter 23X,
Y is incremented from “0” to “1”. And
In the same manner as described above, the first row of the overlapping area C and the divided area B is printed. The above operation is performed by setting the count value of the counter 23Y to the drawing end address Y _{EA in the} Y direction,
_Are repeated until the _count value reaches the drawing end address _XEA in the X direction, thereby completing the printing by the second main scan.

C. Second Example Apparatus The second example apparatus is an image connecting apparatus for synthesizing divided images in halftone units. FIG. 6 is a block diagram showing a schematic configuration of the image processing unit of the second embodiment. The basic configuration is the same as that of the image processing unit of the first embodiment shown in FIG. The difference from the first embodiment is that the pixels for forming the halftone dot are gradation data having a bit width of n bits (for example, 8 bits), and this is one unit, so that the RAM 21 The n-bit gradation data read from the latch circuit 30 is latched in the latch circuit 30 without performing parallel-to-serial conversion as in the first embodiment. In the present embodiment, since the image of the overlapping area is synthesized in halftone units, the mask data written in the ROM 22 may have a 1-bit width for one pixel (one gradation data).

At the time of the first main scanning, the SEL signal is "H".
Level, and since While drawing divided regions A ENB signal is "L" level, the result of the gate circuit G4, G5 outputs together "H" level, the gate circuit G6 ₁
And opened to 6 _n, the parallel gradation data of n bits are applied to the halftone generating circuit 40 as it is through the latch circuit 30. When the overlapping area C is drawn in the first main scan, the ENB signal goes to “H” level,
Mask data read from the 22 through the gate circuit G5, given to each gate circuit G6 ₁ ~G6n, taken gradation data and the logical product of n bits. That is, only when the mask data is “1”, the gradation data is supplied to the halftone dot generating circuit 40 via the latch circuit 30.

At the time of the second main scanning, the SEL signal becomes "L" level. While drawing the overlapping area C,
Since the ENB signal goes to the “H” level, the mask data read from the ROM 22 passes through the gate circuit G4.
It is given to the gate circuit G6 ₁ ~G6n, taken gradation data and the logical product of n bits. At this time, since the mask data is inverted by the gate circuit G4, the gradation data is supplied to the halftone generation circuit 40 via the latch circuit 30 only when the mask data is "0". While drawing divided region B, since the gate circuit G6 ₁ ～G6n is opened, when the gradation data is directly latched to the latch circuit 30 is to draw the divided region A in the first main scanning Is the same as

As described above, in the first main scan, the overlapping area C is drawn by the halftone dots selected according to the mask data. In the second main scan, the halftone dots not selected in the first main scan. By drawing the overlapping area C at points, an image of the overlapping area C is synthesized in halftone units.

FIG. 7 is a block diagram showing a schematic configuration of the halftone dot generating circuit 40. The halftone generation circuit 40 includes a reference table memory 41 storing a group of thresholds for determining the size of halftone dots in accordance with the level of the grayscale data. As shown in FIG. 8, the threshold value group of the reference table memory 41 has a distribution such that the value increases as going outside the halftone dot. Each threshold value of the reference table memory 41 has an address in the X and Y directions. An address in the X direction is specified by the counter 43X, and an address in the Y direction is specified by the counter 43Y. The comparator 42 compares the n-bit grayscale data output from the latch circuit 30 of FIG. 6 with each threshold value read from the reference table memory 41, so that the magnitude corresponding to the level of the grayscale data is obtained. The halftone dots are printed. FIG. 8 schematically shows a process in a case where a pixel having a gradation level of “25” is converted to a halftone dot.

By the way, since the gradation data and the mask data in pixel units read from the RAM 21 have a one-to-one relationship, when one halftone dot is composed of one pixel, one pixel is included in the overlapping area C. The halftone dots printed in the second main scan are different from the halftone dots printed in the second main scan. However, when one halftone dot is composed of a plurality of pixels, in the overlapping area C, as shown in FIG. 9, in the first main scan, a part of the halftone dot is printed as shown by the hatched area in FIG. As a result, the printing phase of the halftone dots is shifted, such that the remaining halftone dots are printed in the second main scan. In this case, the overlap may be set to the start address O _SA region C in advance in the address setting unit 44 in FIG. 7, a second address O _SA set in the address setting unit 44 when the main scanning counter 43X Is set as an initial value, and the count value is sequentially incremented from this initial value, so that the remaining halftone dots that were not printed in the first main scan in the second main scan can be printed.

D. Third Embodiment In the first and second embodiments, the divided images are sequentially printed using one optical scanning system. In the third embodiment, two divided images are printed using two optical scanning systems. Can be printed simultaneously. According to this device,
Since only one feed (sub-scan feed) in the Y-axis direction of the movable table 1 shown in FIG. 3 is required, the printing process efficiency is improved, and the two optical scanning systems are simultaneously sub-scan fed. The accuracy of the scanning feed is improved, and the deviation of the main scanning lines by both scanning systems is reduced. In the apparatus of the present embodiment, similarly to the apparatus of the first embodiment, the image of the overlapping area is formed in dot units.

FIG. 10 is a schematic view of the optical scanning system of the present embodiment. This apparatus includes a laser light source 11a, an AOM 12a, an AOM driver 13a, a polygon mirror 14a, and an fθ lens 15a as a first optical scanning system,
As a second optical scanning system, a laser light source 11b, AOM1
2b, AOM driver 13b, polygon mirror 14b,
Lens 15b.

FIG. 11 is a block diagram showing a schematic configuration of the image processing section of the apparatus of this embodiment. In this embodiment, the X addresses of the RAM 21 and the ROM 22 are alternately switched using the multiplexer (MPX) 31 because the photosensitive material P is simultaneously scanned by the two optical scanning systems described above. For example, when drawing by the first optical scanning system located on the left side of FIG. 10, addressing in the X direction is performed by the count value of the counter 23X, and when drawing by the second optical scanning system on the right side, the adder 32 is used. in performing X-direction address specified by the count value obtained by adding the start address O _SA region C overlaps the count value of the counter 23X. The ROM 22 of the present embodiment has an X-direction address area similar to the RAM 21. The switching of the multiplexer 31 is controlled based on the SEL signal from the controller 27.

The register 33a converts the image data to be given to the first optical scanning system from parallel to serial. The serial image data output from the register 33a is supplied to the gate circuit G9 and the latch circuit 35.
A is supplied to the AOM driver 13a shown in FIG. The register 33b converts the image data to be supplied to the second optical scanning system from parallel to serial. The serial image data output from the register 33b is stored in the gate circuit G10 and the latch circuit 35.
b, it is given to the AOM driver 13a shown in FIG. The gate circuits G7 and G8 are for controlling the mask data read from the ROM 22. The registers 33a, 33b and 34 are loaded with image data or mask data in word units by load signals LD1 to LD3 from the controller 27. Further, in synchronization with the shift clock SCK from the controller 27, data is serially output from each of the registers 33a, 33b, and 34, and the latch circuit 3
Data is latched at 5a and 35b.

Next, the operation of this embodiment will be described. As shown in FIG. 10, at the same time the laser beam LB1 by the first optical scanning system starts scanning the writing start position X _SA in the X direction to the right, area laser beam LB2 overlap the second scanning optical system Scanning starts rightward from the start position of C (address _OSA ). At this time, the controller 27 alternately switches the multiplexers 31 to alternately load the word-based image data of the RAM 21 into the registers 33a and 33b. That is, the count value of the counter 23X is set to R through the multiplexer 31.
By being supplied to the AM 21, image data in word units is read out sequentially from the X-direction drawing start address in the RAM 21 and loaded into the register 33a. Alternating with the reading of the image data described above, by the sum of the adder 32 is supplied to the RAM21 via the multiplexer 31, the image data of word units sequentially from the start address O _SA in the X direction of the overlapping region C in RAM21 Is read and loaded into the register 33b.

The laser beam L by the first optical scanning system
While B1 is scanning divided regions A, i.e., to the start address O _SA and consistent with the comparator 26c counted values overlapping region C of the counter 23X supplied through the multiplexer 31 issues a coincidence detection signal During the controller 2
7 outputs the “L” level ENB1 signal, so that the output of the gate circuit G7 becomes “H” level, and the gate circuit G9 is opened. As a result, the image data in the register 33a is transferred to the gate circuit G9 and the latch circuit 35a.
Through the AOM driver 13a. Also,
While the laser beam LB1 scans the overlapping area C,
That is, the start address O _SA counted values overlapping region C of the counter 23X supplied through a multiplexer 31
While the value is larger than the end address O _EA (corresponding to a period from when the comparator 26c outputs the match detection signal to when the comparator 26b outputs the match detection signal), the controller 27 sets the “H” level. Output the ENB1 signal.
As a result, the mask data in the ROM 22 is stored in the register 3
4 and the gate circuit G7, and the logical product of the image data and the mask data is obtained. As a result, the selected image data in the overlapping area C is sent to the AOM driver 13a via the latch circuit 35a. Given.

When the count value of the counter 23X reaches the end address O _EA of the overlap area C, the controller 27 clears the counter 23X and increments the counter 23Y based on the coincidence detection signal of the comparator 26b, and the next counter 23Y is incremented. Read and print the image data of the line.

In parallel with the above-described printing with the laser beam LB1, the laser beam LB2 of the second optical scanning system is used.
Is performed as follows. The laser beam LB2 scans the overlapping area C at the same time as the start of the main scanning. The laser beam LB2 is located in the region C overlap, the start address O _SA to the comparator 26c the match detection signal matches the region C overlap count of adder 32 supplied through a multiplexer 31 Is detected. As a result, the controller 27 outputs the “H” level ENB2 signal until the comparator 26b next outputs the coincidence detection signal. As a result, the mask data in the ROM 22 is inverted by the gate circuit G8 and supplied to the gate circuit G10, and the logical product of the image data and the inverted mask data is obtained. Thereby, the laser beam LB1
The image data of the dots in the overlapping area C that cannot be printed by the AOM driver 13b is transmitted via the latch circuit 35b.
And the image (dots) of the overlapping area C is selectively printed.

[0048] While the laser beam LB2 is scanning the divided region B, that, consistent with the end address O _SE region C overlap count of adder 32 supplied through the multiplexer 31, comparator 26b Outputs a match detection signal, the controller 27 outputs the “L” level ENB2
Output a signal. As a result, the gate circuit G8 outputs the “H” level, thereby opening the gate circuit G10. Thus, the image data of the divided area B in the RAM 21 is given to the AOM driver 13b of FIG. 10 via the register 33b, the gate circuit G10, and the latch circuit 35b, and the image of the divided area B is printed. As described above, the image data of the next line is read based on the coincidence detection signal of the comparator 26b.
Clears the counter 23X,
This is performed by incrementing Y.

As described above, the laser beams LB1 and LB
2 is repeated until the comparator 26d outputs the coincidence detection signal, whereby the printing of the image on the photosensitive material P is completed.

In the apparatus of the third embodiment, an example has been described in which the overlapping area is synthesized in units of dots by using two laser beams. However, the overlapping area is formed by using two laser beams to form a halftone dot. It is also possible to compose in a unit.

[0051]

As is apparent from the above description, according to the method of the present invention, the first main scanning is performed so that an overlapping area of the image is formed at the boundary of the divided image and one of the divided images is drawn. In the second main scanning for drawing the first image element group appropriately selected in the overlapping area and drawing the other divided image, the second main scanning in the overlapping area not selected in the first main scanning is performed. And the two image element groups are mixed so that even if some deviation occurs between the first main scanning and the second main scanning, the boundary between the divided images is not changed. It becomes less noticeable, and the quality of printed matter can be improved.

Further, according to the apparatus of the present invention, in the first main scan, the overlapping area is selectively drawn with the image data obtained by taking the logical product of the image data of the overlapping area and the mask data. In the second main scanning, the overlapping area is selectively drawn with the image data obtained by taking the logical product of the image data of the overlapping area and the inverted mask data. Therefore, the first main scanning is performed according to the pattern of the mask data. The image element group of the overlapping area selected in the above and the image element group of the overlapping area selected in the second main scan are mixed and drawn.
As a result, the boundary between the divided images becomes less noticeable, and the quality of the printed matter can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of an image connection method according to the present invention.

FIG. 2 is a diagram illustrating an aspect of overlapping image element groups in an overlapping area.

FIG. 3 is a perspective view showing an example of a flat-scanning image recording apparatus according to the embodiment.

FIG. 4 is a diagram showing a schematic configuration of an optical scanning system of the first and second embodiments.

FIG. 5 is a block diagram illustrating a schematic configuration of an image processing unit of the first embodiment device.

FIG. 6 is a block diagram illustrating a schematic configuration of an image processing unit of the second embodiment device.

FIG. 7 is a block diagram showing details of a halftone dot generating circuit of the device of the second embodiment.

FIG. 8 is an explanatory diagram showing a halftone dot forming process in the apparatus of the second embodiment.

FIG. 9 is an explanatory diagram of a halftone dot combining process in an overlapping area.

FIG. 10 is a diagram showing a schematic configuration of an optical scanning system of the third embodiment.

FIG. 11 is a block diagram illustrating a schematic configuration of an image processing unit of the third embodiment device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 movable table 6 exposure head (light beam scanning means) 21 RAM (first storage means) 22 ROM (second storage means) 23X, 23Y counters 25a to 25d address setting units 26a to 26d Comparator 27: Controller G1 to G10: Gate circuit P: Photosensitive material A, B: Split area C: Overlap area

Continuation of the front page (72) Inventor Takashi Kakihara One of 465 Kuze Tsukiyama-cho, Minami-ku, Kyoto, Japan The inside of the Kuze Plant of Nippon Screen Manufacturing Co., Ltd. (56) References JP-A-58-130672 (JP, A) 2-236688 (JP, A)

Claims (2)

(57) [Claims] An image in a flat-scanning image recording apparatus for dividing a large-sized image into small-sized images, connecting the divided images at least in a main scanning direction, and printing a large-sized image on a photosensitive material. In the connection method, an end of a first main scan for drawing one divided image on the same scanning line and the other divided image are arranged such that divided images adjacent to each other in the main scanning direction have overlapping regions. Scanning is performed so that the end of the second main scan for drawing overlaps, and in the first main scan in the overlap area, the first image element group appropriately selected from the image data of the overlap area is scanned. Drawing, in the second main scan in the overlap area, drawing a second image element group not selected in the first main scan,
And drawing in such a way that the two image element groups are mixed in the overlapping area. 2. A flat-scan image recording apparatus which divides a large-sized image into small-sized images, connects the divided images at least in the main scanning direction, and prints the large-sized image on a photosensitive material. In the connection device, a first storage unit that stores image data of an original plate, a second storage unit that stores mask data of an overlapping area between divided images adjacent to each other in the main scanning direction, and one division unit on the same scanning line. An end of the first main scan for drawing an image and a second end for drawing the other divided image
A light beam scanning unit that scans so that an end of the main scanning overlaps with the first scanning unit; and an image data read from the first storage unit and the second image data when the overlapping area is drawn by the first main scanning.
Selectively drawing an overlapping area by giving the data obtained based on the logical product with the mask data read from the storage means to the light beam scanning means,
When drawing the overlapping area by the second main scanning, the image data read from the first storage means and the second
Image data masking for selectively drawing an overlapping area by giving data obtained based on the logical product of inverted mask data obtained by inverting the mask data read from the storage means to the light beam scanning means. Means, and an image connecting device.