JP5078185B2 - Image writing apparatus and image forming apparatus - Google Patents

Description

The present invention is, a printer, a digital copying machine, an image writing viewed apparatus and an image forming apparatus using a light-emitting element array such as an LED array used in the image forming apparatus such as MFP.

As an image writing apparatus for irradiating a photosensitive member with light and writing a latent image, a laser scanning LD scanning method and a method using a light emitting element array in which LED light emitting elements are arranged in an array are used. In this light emitting element array system, when a binary image is output from the image forming apparatus, one dot is printed in a horizontally thick elliptical system depending on the process conditions. This is a 1-dot grid image (5m
m-interval images) appear more clearly, and the vertical lines are printed thicker than the horizontal lines, and the aspect ratio becomes a problem.
In order to solve the problem of the aspect ratio, there is a method of controlling using balance correction data of the LED. For multi-value data, the gradation data for each LED and the data for correcting the output variation in units of blocks composed of a plurality of LEDs are added to the data for correcting the output variation with respect to the average value of the block. The variation of the LED is suppressed by the data.
As a binary method, there is a control that faithfully reproduces gradation by adding binary image data and individual correction data of LEDs, but the dot printing power (printing drive current control) is adjusted. Although the line drawing was improved, the actual situation was that the vertical and horizontal line widths were not improved.
Some LED light-emitting element arrays are not a method of adding correction data and print image data.

In the technique described in Patent Document 1, the number of lightings is controlled by performing several times. However, after image data is transferred even-numbered pixel data, the light-emitting element array unit that performs odd-numbered pixel data transfer is performed twice for each image transfer. Is lit.
In the technique described in Patent Document 2, even numbered data and odd numbered data are transferred several times (twice each), and even numbered data is subjected to pattern recognition in the main scanning direction at the time of the second data transfer, and 1 dot is isolated. If it is a point, the data is processed from “1” to “0”, while the odd-numbered data is processed by the first data, and the vertical line width is narrowed by controlling the lighting time. The width of the vertical and horizontal lines has been improved.
However, in the conventional technique, control for an oblique line image has not been considered.

The present onset bright object is provided with the storage function of the plurality of lines in the image data transfer control unit provides an image writing device and an image forming apparatus capable of deploying main and sub-scanning direction of the image pattern That is.
The present onset bright object retrieves simultaneously the main and sub-scanning of the pixels surrounding the pixel of interest from the storage function, the ability to data identifying the target pixel, can be faithfully recognized the line drawings in one pixel unit An image writing apparatus and an image forming apparatus are provided.
The present onset bright object comprises a matrix of main and sub-scanning of the pixels surrounding the pixel of interest, by allowing the operation setting, is to provide an image writing device and an image forming apparatus can increase or decrease the data pattern .
The present onset bright object, by binary data coded in 4 values, is to provide an image writing device and an image forming apparatus can be subdivided data of one pixel.
The present onset Ming purpose is to identify the pixels to be coded, by recognizing-determined pattern is to provide an image writing device and an image forming apparatus can be subdivided data of one pixel.
The present onset bright object, by the main and sub-scanning pattern is determined to arbitrarily set, to provide an image writing device and an image forming apparatus which can emphasize fine lines that meet the needs of the user It is.
The present onset Ming purpose, the coded pixel, the number of times of read transfer between one line, by converting individually from the code of 4 values into binary data for each count, any pattern An object of the present invention is to provide an image writing apparatus and an image forming apparatus capable of faithfully reproducing fine lines.
The present onset bright object is to provide copy mode, by switching the processing of coded pixel by the printer mode output mode, the image writing device and an image forming apparatus capable of maintaining the image quality.

According to the first aspect of the present invention, a light emitting element array unit including a light emitting element array in which a plurality of light emitting elements whose light emission is controlled according to binary image data is arranged in one direction, and image data for a plurality of lines. And a matrix of three pixels in the main scanning direction and at least three pixels in the sub-scanning direction centered on at least a predetermined target pixel from the image data stored in the storage unit, and the matrix Determining means for determining whether or not the predetermined pixel of interest is an oblique line based on the data, and the determining means determines that the predetermined pixel of interest is black data and part of the diagonal line when the both the two transfer predetermined pixel of interest and a picture data transfer control means for transferring the black data, transferred to the image data transfer control means and said Providing an image writing device, characterized in that each light emitting element of the light emitting element array units to the main scanning of the photosensitive member is driven in accordance with image data.
According to a second aspect of the present invention, a light emitting element array unit including a light emitting element array in which a plurality of light emitting elements whose light emission is controlled according to binary image data is arranged in one direction, and image data for a plurality of lines. And a matrix of three pixels in the main scanning direction and at least three pixels in the sub-scanning direction centered on at least a predetermined target pixel from the image data stored in the storage unit, and the matrix And determining means for determining whether the predetermined pixel of interest is black data and a part of a thin line in the sub-scanning direction based on the data, and the determining means is the data of the predetermined pixel of interest being black In addition, when it is determined that it is a part of a thin line in the sub-scanning direction, image data that transfers one of the two transfers of the predetermined pixel of interest as white data and the other as black data And a transfer control means, characterized in that each light emitting element of the light emitting element array units to the main scanning of the photosensitive member is driven in accordance with the image data transferred to the image data transfer control unit image An image writing apparatus is provided.
According to claim 3 of the present invention, the determining means, further comprising a predetermined function target pixel to determine whether it is part of the black is the data and the main scanning direction of the thin line, the determination unit before Symbol predetermined of the pixel of interest is black data and the main scanning direction is determined to be part was case of fine line, the image data transfer control unit, the black data both in the two transfer of the predetermined pixel of interest The image writing apparatus according to claim 1 is provided.
According to claim 4 of the present invention, provides an image writing instrumentation according to any one of claims 1 to 3, further comprising a setting means for setting in advance the size of the matrix as a pattern To do.
According to a fifth aspect of the present invention, there is provided the image writing apparatus according to the fourth aspect, wherein the coding is performed on the data in the matrix based on the pattern preset by the setting means. .
According to a sixth aspect of the present invention, there is provided the image writing apparatus according to the fourth or fifth aspect, wherein the setting means can arbitrarily set the pattern in advance.
According to claim 7 of the present invention, the determining means, in response to data in said matrix, of claims 1 to 6, wherein the encoding of the code 4 values of image data of the binary An image writing apparatus according to any one of the above items is provided.
According to an eighth aspect of the present invention, there are provided a plurality of the light emitting element arrays arranged in a staggered manner with a predetermined amount shifted in the sub scanning direction with the axial direction of the photoconductor as the main scanning direction and overlapping by a predetermined amount in the main scanning direction. An image writing apparatus according to any one of claims 1 to 7 is provided.
According to a ninth aspect of the present invention, there is provided an image forming apparatus comprising the image writing apparatus according to any one of the first to eighth aspects.

According to the present invention, in the image writing apparatus and the image forming apparatus , the image data transfer control means is provided with a storage function for a plurality of lines, so that image patterns in the main and sub scanning directions can be developed. By controlling the image pattern, the line width of the output image can be improved.

1 is a diagram showing an outline of a copying machine as an embodiment of the present invention. FIG. 3 is a diagram showing a process of a copying machine as an embodiment of the present invention. It is a figure explaining each block of the LED writing control circuit. It is the figure which showed the data transfer to a LED head. It is the figure which showed the method of data processing. It is the figure which showed the dot diameter and the image (1 dot lattice). It is the figure which showed the dot diameter and the image (1 dot diagonal).

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 1 is a block diagram showing an outline of a copying machine according to the present embodiment. The copying machine includes a reading unit 100 as a reading unit that reads a document, an image information storage unit 300 as a storage unit that stores the read document information, and a writing unit 500 for copying the stored information onto a transfer sheet. ,
Further, the system control device 302 is configured to execute and control a series of processes, and an operation unit 400 serving as an operation unit that performs key input to the system control device.

Next, the configuration of the reading unit 100 will be described with reference to FIGS. 1 and 2. FIG. 2 is a side view showing the configuration of the copying machine according to the present embodiment.
First, when the operator inserts a document from the insertion slot, the document is conveyed between the contact sensor 2 and the white roller 3 according to the rotation of the roller 1. The document being conveyed is irradiated by the LED attached to the contact sensor 2, and the reflected light is imaged on the contact sensor 2, and the document image information is read.
The document image formed on the sensor 101 in FIG. 1 is converted into an electrical signal, and this analog signal is amplified by the image amplification circuit 102. The A / D (analog / digital) conversion circuit 103 is
The analog image signal amplified by the image amplification circuit 102 is converted into a multi-value digital image signal for each pixel.

The converted digital image signal is output in synchronization with the clock output from the synchronization control circuit 106, and the shading correction circuit 104 corrects distortion due to unevenness in light amount, contact glass contamination, sensor sensitivity unevenness, and the like. This corrected digital image information is
After being converted into digitally recorded image information by the image processing circuit 105, it is written in the image memory unit 301.

Next, configurations of the system controller 302 and the writing unit 500 that control a series of processes for forming an image signal written in the image memory unit 301 on a transfer sheet will be described.
The system control device 302 has a function of performing overall control. The image data transfer in the reading control circuit 107, the synchronization control circuit 106, the image memory unit 301, and the LED writing control circuit 502 and the drive control circuit 504 make the scanner drive device 108. Then, a motor or the like is driven via the printer driving device 505 to smoothly control the reading document and transfer paper.
In the writing unit 500, the image signal transferred from the image memory unit 301 by the synchronization signal clock is converted into bits by one pixel by the LED writing control circuit 502, and converted into infrared light by the LPH 503.

Next, the process up to recording paper will be described with reference to FIG.
The charging device 4 is called a scorotron charger with a grid that uniformly charges the photosensitive drum 5 to -1200V. Light emitting element array unit (LED head) 6
, The LEDs are arranged in an array and irradiated onto the photosensitive drum 5 through an SLA (Selfoc (registered trademark) lens array). The LED head of the light emitting element array unit 6 corresponds to the LPH 503 in FIG.
When the photoconductor drum 5 is irradiated with LED light based on digital image information, the charge on the surface of the photoconductor flows to the ground of the photoconductor drum 5 due to a photoconductive phenomenon and disappears. Here, the portion where the document density is low does not emit the LED, and the portion where the document density is high emits the LED. As a result, an electrostatic latent image corresponding to the density of the image is formed on the LED light non-irradiated portion of the photosensitive drum 5.

The electrostatic latent image is developed by the developing unit 7. Since the toner in the developing unit 7 is negatively charged by stirring and a bias is applied to −700 V, the toner adheres only to the LED light irradiation portion.
On the other hand, the transfer paper is selected from three paper feed stands and manual feed, and passes through the lower part of the photosensitive drum 5 at a predetermined timing by the registration roller 8, and at this time, the toner image is transferred onto the recording paper by the transfer charger 9. The recording paper is then separated from the photosensitive drum 5 by the separation charger 10, transported by the transport tank 11, and sent to the fixing unit 12. Then, the toner is fixed on the recording paper. The recording paper on which the toner is fixed is sent to the front and back of the apparatus by a paper discharge tray 14 or 13 and discharged.

Next, the flow of image signals from the image memory unit 301 to the writing unit 500 will be described.
The image signal flows from the image memory unit 301 into even pixels (EVEN) and odd pixels (ODD).
) Binary image data is simultaneously sent to the LED writing control circuit 502 at a transfer rate of 16 MHz. The image signals sent in parallel by two pixels are once combined into one line in the LED writing control circuit 502, then assigned to three divisions, and LED heads 503_1, 503_2, 5
Four pixels are simultaneously transferred to 03_3.

Next, each block of the LED write control circuit 502 will be described with reference to FIG.
First, the image data input unit 512 will be described. Binary image signal, ie even pixel (
EVEN), odd pixel (ODD), and timing signal are converted from parallel to serial from the image memory unit 301 using a low voltage operation signal element LVDS receiver and sent to the LED write control circuit 502 at 16 MHz. The LED write control circuit 502 also uses LVDS.
Using receiver, convert serial signal to parallel signal, PKDE / PKDO / CL
Input to the IC 510 as KA, LSYNC_N, LGATE_N, and FGATEIPU_N.

Next, the SRAMs 550_1 to 6 of the image data RAM unit 1 will be described.
The DEOI [1: 0] data output from the IC 510 in units of two pixels is sequentially stored from the SRAM 1 line by line in synchronization with CLKA. Then, three lines of data are stored in the SRAM 1 to 3, while the fourth line is being transferred to the SRAM 4, while another SRAM is being transferred.
Data of 5, 6, 1, 2, and 3 are read in the order of addresses and transferred to the IC 510.
Of the transferred data, pay attention to the data on the first line of the SRAM 1, compare with the main and sub data surrounding the data, encode from 2 values to 4 values, and transfer to the next stage. In addition, 2
The processing of the data on the line is performed while the SRAM 6, while the fifth line is being transferred to the SRAM 5,
The data of 1, 2, 3, 4 are read in order, the data of interest on the second line is compared with the main and sub, encoded from binary to quaternary, and transferred to the next stage.
As described above, the SRAMs 1 to 6 are sequentially toggled to store one line of data, while the other five unstored SRAMs are simultaneously read in the order of addresses, and are used as main / sub matrix patterns for the target line. Code from 2 to 4 values.

Subsequently, the SRAMs 514A_1 to 514A_3 and 514B_1 of the image data RAM unit 2 are used.
˜514B_3 will be described.
Within the IC 510, image signals of even pixels (EVEN 2 bits) and odd pixels (ODD 2 bits) encoded into four values are made into four pixel units, and SRAMDI [7: 0] is set as S
A group SRA is generated by the RAM address signals ADRA [10: 0] and ADRB [10: 0].
M3 (514A_1 to 514A_3), B group SRAM 3 (514B_1 to 514B_
3) is stored at a transfer rate of 8 MHz.
501_1 to 503_3 are the total number of dots 23040 dots (A3 width 7680 dots × 3
Since the image signal transfer is divided into three in this), the image signal for one main scanning line is transferred to the SRAM of the A group.
The image signals of the LED heads 1 and 503_1 are stored in 514A_1, and the LE signals are stored in the SRAM 514A_2.
The image signal of the D head 2 · 503_2 is transferred to the SRAM 514A_3 and the LED head 3 · 503.
_3 image signal is stored.
The image signals sequentially stored in the three A group SRAMs 514A_1 to 514A_3 at 8 MHz are simultaneously read out from the three A group SRAMs (514A_1 to 514A_3) at 16 MHz on the next second line, and are input to the IC 510 again to obtain the image signals. 4 pixels (2 bits * 4 pixels = 8
Bit) is latched with 4 pixels of the next address, and 4 even pixels are extracted from 8 pixels, and the transfer speed is 8 MHz to field memories 515_1 to 515_3 of the image data delay unit.
Sent by. At this time, the LED heads 1 and 503_1 do not perform a delay operation because of the sub-scanning reference.

The image signals of the LED heads 2 and 503_2 are transferred to the field memory 515_1, and the LED heads 3 and 503_3 are transferred to the field memory 515_3. Reading from the SRAM group is performed four times during one line, and even-numbered pixels, odd-numbered pixels, and the second even-numbered pixels and odd-numbered pixels are controlled in units of four pixels.
While performing read control from the SRAM of the first line, the next line is moved to the SR of the B group.
The image signals are stored in the three AMs 514B_1 to 514B_3 in the same manner as the group A.
This read / write operation is performed by three A group SRAMs 514A_1 to 514A_3 and B group SRA.
By connecting the M3 pieces 514B_1 to 514B_3, the lines are connected.

Next, the field memories 515_1 to 515_3 of the image data delay unit will be described.
(1) Field memory 515_1 of the image data delay unit of the LED head 2 · 503_2
515_2, A3 width LED heads 505_1 to 505_3 are arranged in a staggered manner, so LED heads 2 and 503_2 are mounted with a shift of 17.5 mm in the sub-scanning direction on the mechanical layout. ing.
For this reason, three A group SRAMs (514A_1 to 514A_3) and three B group SRAMs (5
14B_1 to 514B_3) simultaneously processing image signals output from the LED head 2.
When transferred to 503_2, LED heads 2 and 503 are connected to LED heads 1 and 503_1.
_2 is 17.5 mm (17.5 mm / 42.3 μm (600 dpi 1d in the sub-scanning direction)
ot) = 416 lines).

In order to correct this mechanical shift, the A group SRAM 514A_2 and the B group SRA at 4 MHz.
The image signals of the LED heads 2 and 503_2 outputted from the M514B_2 are written in 180 pixels (fixed) at 2 MHz in the order of transfer lines in the field memory 515_1 in units of 8 pixels. Next, image signals are read from the field memory 515_1 at 2 MHz in the order of writing, and at the same time, 236 lines (variable) are written to the cascade-connected field memory 515_2.

Next, an image signal is read from the field memory 515_2 at 8 MHz in the order of writing, and is input to the IC 510 again as L2DFMO [7: 0]. As a result, the image signals of the LED heads 2 and 503_2 are delayed by 416 lines. The number of lines to be delayed varies depending on the LED head 2,503_2 component system and assembly variations.
Control in units of one line (42.3 um) is possible.

(2) LED head 3, 503_3 image data delay unit Since three A3 width LED heads (503_1 to 503_3) are arranged in a staggered manner, LED
The LED heads 3 and 503_3 are attached with a shift of 0.5 mm in the sub-scanning direction on the mechanical layout with the heads 1 and 503_1 as a reference.
For this reason, three A group SRAMs 514A_1 to 514A_3 and three B group SRAMs (514
B_1 to 514B_3) simultaneously processing image signals output from the LED heads 3 and 50
When transferred to 3_3, the LED head 3 · 503_3 is 0.5 mm (0.5 mm / 42.3 μm (1 dot at 600 dpi) = 1 in the sub scanning direction with respect to the LED head 1 · 503_1.
2 lines) Printing is shifted.

In order to correct this mechanical shift, the A group SRAM 514A_3 and the B group SRA at 4 MHz.
The image signals of the LED heads 3 and 503_3 output from the M3 and 514B_3 are written into the field memory 515_3 with 12 lines in the order of transfer lines at 8 MHz in units of 8 pixels.
Next, an image signal is read from the field memory 515_3 at 2 MHz in the order of writing, and is input again to the IC 510 as L3DFMO [7: 0]. As a result, the image signals of the LED heads 3 and 503_3 are delayed by 12 lines.
Since the number of lines to be delayed varies depending on the parts system of LED heads 3 and 503_3 and the variation in assembly, control in units of one line (42.3 um) is possible.

Next, the SRAM groups 514A_1 to 514B_1 to 514B_1 to 3 in the image data RAM unit 2 will be described.
The image data L1DI [7: 0] of the LED head 1 from the image data RAM unit 1, the image data L2DFMO [7: 0] of the LED heads 2 and 3 from the image data delay unit, L3DFM
O [7: 0] is stored in the SRAM group 514A_1 of the image data RAM unit 2 via the IC 510.
3, 514B_1 to 3 at a transfer rate of 2 MHz.
The stored image data is read out four times at the transfer rate of 8 MHz between the next lines. Since the address is the LED head 7680 dots and the unit is 8 pixels, it corresponds to 960 addresses.
This 960 address is repeated four times. The image data read in units of 8 pixels is the IC 51
Data is converted into units of 4 pixels within 0 and transferred to the image data output unit 519.
Further, the SRAM groups 550B_1 to 550B_1 are read while being read by the SRAM groups 550A_1 to 550A_1.
In step 3, the next line data is written, and lines are written and read alternately.

Next, the image data output unit 519 will be described.
The 4-bit unit image data of the LED heads 1 to 3 processed by the image data RAM unit 2 is output together with the LPH control signal, and the LED heads 503_1 to 50 through the driver.
3_3 is transferred at a speed of 8 MHz (L1 to L3CLK are rising at 4 MHz,
Data is confirmed at the falling edge).

Next, the light quantity correction RAM unit 516 will be described.
The LED heads 503_1 to 503_3 are equipped with a light amount correction ROM in each LED head for correction data for each LED element and correction data for each LED array chip in order to correct variation in light amount of each LED element.
When the power is turned on, the light quantity correction data of the LED head 503_1 is first read out by CPLD control of the IC 510, serial / parallel converted, and correction data HOSEID [
7: 0] is stored in the light amount correction RAM unit 516 by the address. After storing all the correction data, this time, it is read from the light amount correction data SRAM and transferred again to the LED head 503_1. This operation is sequentially performed with the LED heads 2 and 3.
The transferred light quantity correction data is configured such that the correction data is held inside the LED heads 503_1 to 503_3 unless the LED heads 503_1 to 503_3 are turned off.

Next, the system controller 302 will be described.
The write condition setting to the LED write control circuit 502 is performed by setting the control signal input data bus LDATA [7: 0], the address bus LADR [5: 0], the latch signal VDBCS, and the P sensor pattern signal SGATE_N from the system controller 302. Control is performed by inputting to the IC 510.

The overall configuration of the machine, the image data transfer control to the specific LED head of this embodiment configured by the LED writing control circuit 502, the lighting time, the print dot diameter, and the image described above will be described below. .
First, in order to capture the overall control, a data transfer method to the LED head will be described.
FIG. 4 shows the timing for data transfer to the LED head. RLS
YNC is an interval of one line in the main scanning, and image data is transferred at the rising and falling edges of the clock. DATA is image data in units of 4 pixels.
As the transfer image data, first, (1) even pixel data: EVEN DATA of the LED head 7680 pixels (3840 pixels * 2) is transferred. The number of pixels is the LED head total pixel 7680
Since 4 dots are transferred at 3840 dots, which is half of the dots, 3840/4 = 960 counts. After the transfer, the data is latched by the LOAD signal.

Next, (2) odd pixel data: ODD DATA is transferred and latched again by the LOAD signal. Again, (3) even data, (4) odd data transfer, latch, printing, and data transfer are repeated twice.
Lighting signal: STRB is LOW active, and even pixel data printing in (1)
When the odd pixel data is transferred (2), the LED is emitted with LOW5. When the odd pixel data is printed with (2), the LED is emitted with LOW6 when the even pixel data is transferred (3).
Again, the even pixel data of (3) is printed as LOW7 when the odd pixel data of (4) is transferred, and the odd pixel data of (4) is then printed at LOW8.
At this time, the STRB signal is LOW and LED is emitted, and by controlling the LOW period, the image printing time can be adjusted, the dot power can be controlled, and the image density can be made uniform. The image density is regulated by process conditions and the like, and the machine condition is 10% of the main scanning 1 line interval.
Front and rear STRB lighting / printing is appropriate. 10% is calculated from the relationship between the copy linear velocity and the pixel density, and in this case, the main scanning interval is 705.6 usec.
. The lighting period is 56 usec.
Further, in the copier mode, the data transfer is controlled once and the lighting signal is controlled once, that is, data transfer (1) → (2) and STRBs 5 and 6 in FIG. . In this case, data transfer is twice {first time in (1) (2), second time in (3) (4)}, and STR
The B signal is also 10% duty at 5 and 7 and 10% duty at 6 and 8. This 10% is distributed and transferred at a ratio control of 3: 1. Therefore, they are 7.5% and 2.5%.

Next, data processing in this case up to the DATA transfer will be described with reference to FIG.
The main scans 0 to 23,... Are one line data, and the sub scans 1 to 5 are the number of lines, which is a storage function unit for a plurality of lines. By this storage, main / sub matrix patterns can be determined.
As an example, the line-of-interest sub-scan 3 is raised from the stored data for each line. Pixel of interest (
The pixel 100 in the main scanning 1) is black and the data is 1. Here, the main surrounding pixels 100
When viewed from a matrix of sub 3 pixels × 3 pixels, it can be determined that the pixel 100 is an oblique line.
In the determination only in the main scanning direction, the pixel 100 is determined as a 1-dot isolated point.
In the main / sub matrix pattern, if it is an oblique pattern, it fits a predetermined pattern, so that it becomes 11b in the quaternary coding. As a result, the diagonal line is
By not thinning out the data, the image can be made clear.

When the pixels in the sub-scanning third line of the target line are sequentially determined in a matrix by the above method, the pixel 101 in the main scanning 5 can be determined as a vertical line from the matrix. Here, when converting from binary data to quaternary encoding, it is determined whether the pixel is an even pixel or an odd pixel, and if it is determined that the vertical pattern is an odd pixel, the pixel 101 becomes a 01b code.
Further, in the pixel 102, it is determined that the horizontal line is an odd number, and the 11b code is obtained.
The odd number of data is 00b code, and the pixel 104 is determined to be an even number of 1 dot isolated points.
In the code / pixel 105, it is determined that the diagonal line is an even number and the 11b code is obtained.
As described above, in the second embodiment, the main and sub pixels surrounding the target pixel are simultaneously extracted from the storage function, whereby the data of the target pixel can be recognized, and the line drawing can be faithfully expressed in units of one pixel.
Further, in the third embodiment, the pixels of the surrounding matrix are changed from 3 pixels × 3 pixels to 5 pixels ×
The number of pixels can be increased to 5 pixels, and the pattern variations can be increased. As described above, in the third embodiment, the matrix of the main and scanning pixels surrounding the target pixel is set to be operable, so that the data pattern can be increased or decreased, and the line drawing can be reproduced more faithfully.

In the fourth embodiment, the pixel of interest is coded from binary to quaternary so that image data conversion to the LED head can be performed. Therefore, in the fourth embodiment, data in units of one pixel can be subdivided by encoding binary data into four values.
In the fifth embodiment, in the fourth embodiment, identification of pixels to be coded is determined by recognizing a predetermined pattern. For this reason, the data for each pixel can be subdivided, and the ratio of the vertical, horizontal, and diagonal line widths can be improved.
In the sixth embodiment, the main and sub-scanning patterns determined in the fifth embodiment can be set arbitrarily. Therefore, it is possible to emphasize thin lines that meet the needs of the user.

FIG. 5 shows the code of the pixel whose pattern is recognized in the sub-scan 3 of the target line 106. The pixel of interest is the pixel of interest 101 and the pixel of interest 104. This is because the coded pixels are read in units of 4 pixels, read out from the image data RAM unit of FIG. 3, and latched to 8 units, and from here, even pixels and odd pixels are converted into units of 4 pixels. Select. Although the data transfer order of (1) to (4) has been described with reference to FIG. 4, FIG. 5 (1) to (4) are suitable for this.
(1) and (3) in FIG. 5 are even data. Only even numbers are selected from the coded pixels of the target line 106, and the coding is converted into 1-bit data. In (1), 00b → 0, 10
→ 1, 11 → 1, and (3) is the same as 00b → 0 and 11b → 1, but 10b → 0.
The data values of LPHCLK1 and 107 and LPHCLK2 and 108 in (1) and (3) are the same, but in LPHCLK3 and 109, (1) is 1010 and (3) is 1000.
Thus, the data is set to 0. Then, even if the lighting signal is turned ON, the data is 0 and printing is not performed, so that only the time of the first lighting signal is required and the line width can be reduced.

In addition, (2) and (4) are odd data. When only the odd number of coded pixels of the target line 106 is selected and the coding is converted into 1-bit data, the 01b code is changed to 0 in (2).
In (4), the data is converted by setting it to 1. Therefore, LPHCLK1 · 107 (
2) is 0001 and (4) is 0101.
As described above, according to the seventh embodiment, a pixel of interest can be coded from the main / sub-scan pattern, read out several times between one line and transferred, and the line can be narrowed from data conversion and lighting time. . In this seventh embodiment, the coded pixels are individually converted from four-value coding to binary data every number of times by several times of read-out transfer between one line, so any pattern can be used. Fine lines can be faithfully reproduced.
In the eighth embodiment, the output mode, that is, the copier mode and the printer mode can be separated, so that the gradation in the image processing in the copier mode and the data processing in the printer mode is achieved. , Line drawings can be faithfully reproduced. This control is control in the printer mode.

Next, the print dot diameter and image of a one-dot cross will be described with reference to FIG.
First, even pixel data 9 is printed with a duty of 7.5%, then odd data 10 is printed with a duty 2
. Print at 5%. Since the duty is 2.5%, the lighting time is short, so the density becomes light.
Next, the even-numbered pixel data 11 is printed again with a duty of 2.5%. When a pattern of 1 dot isolated point is recognized, data 0 is not printed. Finally, the odd pixel data 12 is dut
Printing at y7.5%.
Therefore, the dot diameter is printed only with a duty of 7.5% by the data processing control in the vertical line, and the horizontal line is printed with 10% of duty 2.5% + 7.5%, and the density is enhanced by the edge effect. . With the above printing format, the ratio of the vertical line width 13 to the horizontal line width 14 of the image is improved.

Further, with reference to FIG. 7, an oblique line print dot and an image will be described. Conventionally, in the case of an oblique line for control at an isolated point of 1 dot in the main scanning direction, it is recognized as a vertical line in the same manner as in FIG. 6, and if it is even pixel data, the first printing is performed and the second printing is not performed, and the duty is 10%. For du
ty 7.5%, the density becomes lighter and the line becomes faint, so this case makes it possible to print both times by recognizing diagonal lines with the main / sub scanning pattern, and the density is the same as the copy with a lighting time of 10%. It will be possible to faithfully represent lines with various patterns.

DESCRIPTION OF SYMBOLS 100 Reading part 101 Sensor 102 Image amplification circuit 103 AD conversion circuit 104 Shading correction circuit 105 Image processing circuit 106 Synchronization control circuit 107 Reading control circuit 108 Scanner drive device 300 Image information storage part 301 Image memory part 302 System control apparatus 400 Operation part 500 Writing unit 502 LED writing control circuit 503 LED heads 1 to 3
504 Drive control circuit 505 Printer drive device 510 IC
512 Image data input unit 516 Light amount correction RAM unit 514A SRAM 1 to 3
514B SRAM 1-3
519 Image data output unit 550 SRAM1 to SRAM6

Japanese Patent Application No. 2003-412065 Japanese Patent Application No. 2005-36620

Claims (9)

A light emitting element array unit including a light emitting element array in which a plurality of light emitting elements whose light emission is controlled according to binary image data are arranged in one direction;
Storage means for storing image data for a plurality of lines;
From the image data stored in the storage means, data of a matrix of at least three pixels in the main scanning direction and three pixels in the sub-scanning direction centering on a predetermined target pixel is read, and the predetermined data is based on the matrix data. A determination means for determining whether the target pixel is a diagonal line;
When the determination unit determines that the predetermined pixel of interest is black data and is a part of an oblique line, an image in which black data is transferred in two transfers of the predetermined pixel of interest Data transfer control means;
With
An image writing apparatus, wherein each light emitting element of the light emitting element array unit is driven in accordance with the image data transferred to the image data transfer control means to perform main scanning on the photosensitive member. A light emitting element array unit including a light emitting element array in which a plurality of light emitting elements whose light emission is controlled according to binary image data are arranged in one direction;
Storage means for storing image data for a plurality of lines;
From the image data stored in the storage means, data of a matrix of at least three pixels in the main scanning direction and three pixels in the sub-scanning direction centering on a predetermined target pixel is read, and the predetermined data is based on the matrix data. Determining means for determining whether the pixel of interest is black data and part of a thin line in the sub-scanning direction;
When the determination unit determines that the predetermined pixel of interest is black data and is a part of a thin line in the sub-scanning direction, one of the two transfers of the predetermined pixel of interest is white. Image data transfer control means for transferring the data and the other data as black data ,
Wherein the image data transfer control unit images writing device the light-emitting elements are you, characterized in that the main scanning of the photosensitive member is driven in the light-emitting element array unit in accordance with the image data transferred to. The determination unit further includes a function of determining whether the predetermined pixel of interest is black data and part of a thin line in the main scanning direction,
The determination means before Symbol predetermined target pixel is a black data and the main scanning direction of the determined if as part of fine line, the image data transfer control means of two of the predetermined pixel of interest image writing apparatus according to claim 1 or claim 2, characterized in that to transfer any black data in the transfer. Image writing apparatus according to any one of claims 1 to 3, further comprising a setting means for setting in advance the size of the matrix as a pattern. 5. The image writing apparatus according to claim 4 , wherein the coding is performed on the data in the matrix based on the pattern preset by the setting unit. The setting means, the image writing apparatus according to claim 4 or claim 5, characterized in that the pattern in advance can be set arbitrarily. The image according to any one of claims 1 to 6 , wherein the determination unit encodes the binary image data into a quaternary code in accordance with data in the matrix. Writing device. 2. A plurality of the light emitting element arrays arranged in a staggered manner with a predetermined amount shifted in the sub-scanning direction with the axial direction of the photoconductor as the main scanning direction and overlapping by a predetermined amount in the main scanning direction. The image writing device according to claim 7 . An image forming apparatus comprising the image writing apparatus according to any one of claims 1 to 8.

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