JP4921752B2 - Image writing apparatus and image forming apparatus - Google Patents

Description

The present invention relates to an image writing apparatus and an image forming apparatus using a light emitting element array such as an LED array used in an image forming apparatus such as a printer, a digital copying machine, and a multifunction peripheral.

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. If this is a 1-dot lattice image (image with an interval of 5 mm), it appears 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.
Japanese Patent Application No. 2003-412065 Japanese Patent Application No. 2005-36620

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.

Accordingly, a first object of the present invention is to provide a digital light-emitting element writing device capable of developing image patterns in the main and sub-scanning directions by providing a storage function for a plurality of lines in the image data transfer control means. That is.
A second object of the present invention is to accurately recognize a line image in units of one pixel by simultaneously extracting main and sub-scanning pixels surrounding the target pixel from the storage function and identifying the data of the target pixel. It is an object of the present invention to provide a digital light emitting device writing device that can be used.
A third object of the present invention is to provide a digital light-emitting element writing device capable of increasing / decreasing a data pattern by enabling operation setting of a matrix of main / sub-scanning pixels surrounding a target pixel.
A fourth object of the present invention is to provide a digital light-emitting element writing device capable of subdividing data in units of one pixel by converting binary data into quaternary encoding.
A fifth object of the present invention is to provide a digital light emitting element writing device capable of subdividing data in units of one pixel by recognizing a predetermined pattern for identifying pixels to be encoded.
A sixth object of the present invention is to provide a digital light-emitting element writing device capable of emphasizing fine lines that meet the needs of the user by allowing the determined main / sub-scan patterns to be arbitrarily set. .
A seventh object of the present invention is that any pattern can be obtained by individually converting coded pixels from four-valued coding to binary data by the number of times of read and transfer between one line. It is an object of the present invention to provide a digital light emitting element writing device capable of faithfully reproducing a thin line.
An eighth object of the present invention is to provide a digital light-emitting element writing device capable of maintaining image quality by switching the processing of pixels coded according to the output mode of the copy mode and the printer mode.

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 one line. the and a picture data transfer control means you send 2 rotates in the light - emitting element array units, each light emitting element of the light emitting element array unit in accordance with the image data transferred to the image data transfer control means drives the has been photoconductor an image writing device you main scanning, further comprising a storage means for storing image data of at least three lines, the image data transfer control means, the image data stored in said storage means from at least three pixels in the main scanning direction about the predetermined target pixel, it reads the matrix of data containing at least three pixels in the sub-scanning direction, of the matrix Depending on the chromatography data, whether the predetermined two transfer sac Chi one target pixel transferring white data, once more as a black data when the predetermined target pixel is black data, or Either the two transfers of the predetermined pixel of interest are transferred as black data , and the predetermined pixel of interest in the matrix data is black data. In the case of an isolated point in which all the pixels are white data, one of the two transfers of the predetermined pixel of interest is transferred as white data and the other is transferred as black data. An image writing device is provided.
In the second aspect of the present invention, when the image data transfer control unit determines that the predetermined pixel of interest is black data and the predetermined pixel of interest is a part of a diagonal line , 2. The image writing apparatus according to claim 1 , wherein black data is transferred in both transfers.
In the invention of claim 3, wherein said image data transfer control means is data predetermined target pixel is black, if the predetermined target pixel is part of a sub-scanning direction thin line, the predetermined target 3. The image writing apparatus according to claim 1, wherein one of the two pixel transfers is transferred as white data, and the other is transferred as black data.
In the invention of claim 4, wherein said image data transfer control means is data predetermined target pixel is black, if the predetermined target pixel is part of the primary scanning direction of the thin line, the predetermined target providing an image writing apparatus according to any one of claims 1 to 3, characterized in that to transfer both the black data in two transfer pixel.
According to a fifth aspect of the present invention, there is provided the image writing apparatus according to any one of the first to fourth aspects, further comprising setting means for setting the size of the matrix.
In the invention of claim 6, wherein said image data transfer control means in accordance with the data in the matrix, any claim 1 to 5, wherein the encoding of the 4 values of image data of the binary An image writing apparatus according to claim 1 is provided.
In the invention of claim 7, wherein, data after the encoding, to the data in the matrix, according to claim 6, characterized in that it is determined by recognizing a predetermined pattern An image writing apparatus is provided.
According to an eighth aspect of the present invention, there is provided the image writing apparatus according to the seventh aspect, wherein the predetermined pattern can be arbitrarily set.
According to a ninth aspect of the present invention, the coded pixel is converted into a binary image from four-value coded data every number of times by several times of read transfer between one line by the image data transfer control means. It is converted into the data individually, to provide an image writing apparatus according to any one of claims 6-7, characterized in that to transfer to the light emitting element array units.
In the invention of claim 1 0, wherein a plurality of the light emitting element array, the plurality of light emitting element array, the axial direction of the photosensitive body a predetermined amount shifted in the sub-scanning direction as a main scanning direction, Tokoro in the main scanning direction providing an image writing apparatus according to any one of claims 1 to 9, characterized in that it is arranged in a zigzag manner in a state overlapping quantitative.
In the invention of claim 1 1, wherein the image data transfer control means, any one of claims 1 to 1 0, characterized in that for transferring the image data so as to vary the lighting time of each light emitting element The image writing apparatus described in 1. is provided.
According to a second 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 eleventh aspects.

  According to the present invention, in the digital light emitting device writing 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 pattern, the line width of the output image can be improved.

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. The system control device 302 executes and controls a series of processes, and an operation unit 400 as operation means for performing 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. An A / D (analog / digital) conversion circuit 103 converts the analog image signal amplified by the image amplification circuit 102 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. The corrected digital image information is converted into digital recording image information by the image processing circuit 105 and then 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. The light emitting element array unit (LED head) 6 arranges LEDs in an array and irradiates the photosensitive drum 5 through an SLA (selfoc 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.
Regarding the flow of the image signal, binary image data of even pixels (EVEN) and odd pixels (ODD) is simultaneously sent from the image memory unit 301 to the LED writing control circuit 502 at a transfer rate of 16 MHz. The image signals sent in two-pixel parallel are temporarily combined into one line in the LED writing control circuit 502, assigned to three divisions, and simultaneously transferred to the LED heads 503_1, 503_2, and 503_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. The binary image signal, that is, even pixel (EVEN), odd pixel (ODD), and timing signal are converted from parallel to serial from the image memory unit 301 using the low voltage operation signal element LVDS receiver, and the LED write control circuit 502 Is sent at 16MHz. The LED write control circuit 502 also uses an LVDS receiver to convert a serial signal into a parallel signal, and inputs the converted signal to the IC 510 as PKDE, PKDO, CLKA, 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 SRAMs 1 to 3, and while the fourth line is being transferred to the SRAM 4, the data of the other SRAMs 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. Further, in the data processing for the second line, while the fifth line is being transferred to the SRAM 5, the data in the SRAMs 6, 1, 2, 3 and 4 are sequentially read and the attention data on the second line is compared with the main and sub. Then, it is coded from 2 values to 4 values 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.

Next, the SRAMs 514A_1 to 514A_3 and 514B_1 to 514B_3 of the image data RAM unit 2 will be described.
In 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 SRAM address signal ADRA [10] is set as SRAMDI [7: 0]. : 0] and ADRB [10: 0], the data is stored in 3 group A SRAMs (514A_1 to 514A_3) and 3 group B SRAMs (514B_1 to 514B_3) at a transfer rate of 8 MHz.
Since 501_1 to 503_3 have a total number of dots 23040 dots (A3 width 7680 dots × 3) and the image signal transfer is divided into three, the image signals for one main scanning line are transferred to the A group of SRAMs 514A_1 and the image signals of the LED heads 1 and 503_1. The image signals of the LED heads 2 and 503_2 are stored in the SRAM 514A_2, and the image signals of the LED heads 3 and 503_3 are stored in the SRAM 514A_3.
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 bits) are latched with 4 pixels of the next address, and 4 even pixels are extracted from the 8 pixels and transferred to the field memories 515_1 to 515_3 of the image data delay unit at a transfer rate of 8 MHz. 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 the readout control from the SRAM of the first line is being performed, the image signal is stored in the three lines of the B group SRAMs 514B_1 to 514B_3 in the same manner as in the A group.
This read / write operation is performed by toggling the three A group SRAMs 514A_1 to 514A_3 and the three B group SRAMs 514B_1 to 514B_3, thereby connecting the lines.

Next, the field memories 515_1 to 515_3 of the image data delay unit will be described.
(1) Since three of the field memories 515_1 and 515_2 and the A3 width LED heads 505_1 to 505_3 of the image data delay unit of the LED heads 2 and 503_2 are arranged in a staggered manner, the LED head 2 is based on the LED heads 1 and 503_1. 503_2 is mounted with a shift of 17.5 mm in the sub-scanning direction due to the mechanical layout.
For this reason, if the image signals output from the three A-group SRAMs (514A_1 to 514A_3) and the three B-group SRAMs (514B_1 to 514B_3) are simultaneously processed and transferred to the LED heads 2 and 503_2, The LED head 2 · 503_2 prints with a shift of 17.5 mm (17.5 mm / 42.3 μm (600 dots per dot) = 416 lines) in the sub-scanning direction.

  In order to correct this mechanical shift, the image signals of the LED heads 2 and 503_2 output from the A group SRAM 514A_2 and the B group SRAM 514B_2 at 4 MHz are set to 8 pixel units and transferred to the field memory 515_1 in 180 MHz at 2 MHz in the order of transfer lines (fixed). Write. 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 part system and assembly variation of the LED heads 2 and 503_2, and thus can be controlled in units of one line (42.3 um).

(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 heads 1, 503_1 are used as a reference. It is attached with a shift of 0.5 mm in the sub-scanning direction.
Therefore, when the image signals output from the three A-group SRAMs 514A_1 to 514A_3 and the three B-group SRAMs (514B_1 to 514B_3) are simultaneously processed and transferred to the LED heads 3 and 503_3, the LED heads 3 and 503_1 are connected to the LED heads 3 and 503_1. 503_3 is printed with a shift of 0.5 mm (0.5 mm / 42.3 μm (1 dot at 600 dpi) = 12 lines) in the sub-scanning direction.

In order to correct this mechanical shift, the image signals of the LED heads 3 and 503_3 output from the A group SRAM 514A_3 and the B group SRAMs 3 and 514B_3 at 4 MHz are written in 12 pixels at 2 MHz in the order of transfer lines in the field memory 515_3 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 and the image data L2DFMO [7: 0] and L3DFMO [7: 0] of the LED heads 2 and 3 from the image data delay unit are IC510. Are stored in the SRAM groups 514A_1 to 514A_1 to 514B_1 to 3 at the transfer rate of 2 MHz, respectively.
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. Image data read in units of 8 pixels is converted into units of 4 pixels in the IC 510 and transferred to the image data output unit 519.
Further, while the SRAM groups 550A_1 to 550A_3 are being read, the SRAM group 550B_1 to 550_3 writes the next line data, and alternately performs line writing and reading.

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 transferred to the LED heads 503_1 to 503_3 at a speed of 8 MHz via the driver (L1). (L3CLK is determined at the rising and falling edges of 4 MHz).

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 amount correction data of the LED head 503_1 is first read by the CPLD control of the IC 510, serial / parallel converted, and stored in the light amount correction RAM unit 516 by the address as 8-bit unit correction data HOSEID [7: 0]. 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. RLSYNC is an interval of one line in the main scanning, and transfers image data 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. Since the number of pixels is 3840 dots, which is half of the total number of pixels of the LED head 7680 dots, and 4 dots are simultaneously transferred, 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.
The lighting signal: STRB is LOW active, and even pixel data (1) is printed with LOW5 when the odd pixel data is transferred (2), and LED emission is performed when odd pixel data is printed (2) ( At the time of even-numbered pixel data transfer of 3), the LED is made to emit LOW6.
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. As the machine condition, STRB lighting / printing of about 10% of the main scanning 1 line interval is appropriate. 10% is calculated from the relationship between the copy linear velocity and the pixel density. In this case, the main scanning interval is 705.6 usec, and 10% is 70.56 usec lighting period.
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, the data transfer is twice {first time at (1) (2), second time at (3) (4)}, and the STRB signal is duty 10% at 5, 7, and duty 10% at 6, 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. The pixel 100 of the target pixel (main scanning 1) is black and the data is 1. Here, when viewed from a matrix of main and sub 3 pixels × 3 pixels surrounding the pixel 100, it can be determined that the pixel 100 is an oblique line.
In the determination only in the main scanning direction, this pixel 100 is determined to be a 1-dot isolated point. However, in the main / sub matrix pattern, if it is an oblique pattern, it matches a predetermined pattern. In the value encoding, 11b is obtained. As a result, the diagonal lines can clear the image by not thinning out the data.

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, the pixel 102 is determined to be an odd number of horizontal lines and becomes an 11b code, the pixel 103 is determined to be an odd number of 0 data and 00b code, the pixel 104 is determined to be an even number of 1 dot isolated points, and the 10b code and the pixel 105 are inclined lines. It is determined as an even number of 11b code.
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.
Furthermore, in the third embodiment, the pixels of the surrounding matrix can be changed from 3 pixels × 3 pixels to 5 pixels × 5 pixels, and the pattern variations can be further 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. In FIG. 4, the data transfer order of (1) to (4) has been described.
(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 in (3), 00b → 0 and 11b → 1, but 10b → 0.
The data values of LPHCLK1 · 107 and LPHCLK2 · 108 in (1) and (3) are the same, but in LPHCLK3 · 109, (1) is 1010 and (3) is 1000 and the data is 0. It will be. 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.

Also, (2) and (4) are odd data, and if only the odd number of the coded pixel of the target line 106 is selected and the coding is converted into 1-bit data, the 01b code is set 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, the even pixel data 9 is printed with a duty of 7.5%, and then the odd data 10 is printed with a duty of 2.5%. 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, odd pixel data 12 is printed with a duty of 7.5%.
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%. On the other hand, the density becomes 7.5% and the density becomes light and the line becomes faint. Therefore, according to this case, the main / sub-scanning pattern is printed twice by recognizing the oblique line, and the density is 10% with the lighting time of 10%. Will be similar to copying, and will be able to faithfully represent lines in various patterns.

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).

Explanation of symbols

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

Claims (12)

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;
The image data of one line and a picture data transfer control means you send 2 rotates in the light - emitting element array units, wherein the light-emitting element array unit in accordance with the image data transferred to the image data transfer control means photoreceptor each light emitting element is driven in a an image writing device you main scanning,
Storage means for storing image data for at least three lines;
The image data transfer control means, from the stored image data in the storage unit, at least three pixels in the main scanning direction about the predetermined target pixel, a matrix of data containing at least three pixels in the sub scanning direction read transfer, in accordance with the data of the matrix, two transfer sac Chi once white data of the predetermined target pixel when the predetermined target pixel is black data, once more as a black data Or performing two transfers of the predetermined pixel of interest both as black data , and the predetermined pixel of interest is black data among the data of the matrix, In the case of an isolated point that is all white data around the predetermined pixel of interest, one of the two transfers of the predetermined pixel of interest is white data and the other is black data. Forward Image writing device, characterized in that. The image data transfer control means is data predetermined target pixel is black and the predetermined target pixel is determined to be part of a diagonal line, either in the two transfer of the predetermined target pixel black The image writing apparatus according to claim 1 , wherein the data is transferred. The image data transfer control means is data predetermined target pixel is black, if the predetermined target pixel is part of a sub-scanning direction of the thin line, of the two transfer of the predetermined pixel of interest 3. The image writing apparatus according to claim 1, wherein one time is transferred as white data and the other is transferred as black data. 4. When the predetermined pixel of interest is black data and the predetermined pixel of interest is a part of a thin line in the main scanning direction, the image data transfer control unit determines which of the two pixels of the predetermined pixel of interest is transferred twice. image writing apparatus according to any one of claims 1 to 3 characterized in that it also transfers the black data. Image writing apparatus according to any one of claims 1 to 4, further comprising a setting means for setting the size of said matrix. The image data transfer control means in accordance with the data in the matrix, the image writing according to any one of claims 1 to 5, wherein the encoding of the 4 values of image data of the binary apparatus. 7. The image writing apparatus according to claim 6 , wherein the data after the encoding is determined by recognizing a predetermined pattern with respect to the data in the matrix. The image writing apparatus according to claim 7, wherein the predetermined pattern can be arbitrarily set. The coded pixels are individually converted from quaternary coded data to binary image data for each number of times by read and transfer several times between one line by the image data transfer control means, image writing apparatus according to any one of claims 6-7, characterized in that for transferring the light-emitting element array units. A plurality of the light emitting element arrays are provided, and the plurality of light emitting element arrays are 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 a predetermined amount overlapping in the main scanning direction. image writing apparatus according to any one of claims 1 to 9, wherein Rukoto. The image data transfer control means, an image writing apparatus according to any one of claims 1 to 1 0, characterized in that for transferring the image data so as to vary the lighting time of each light emitting element. An image forming apparatus comprising the image writing apparatus according to any one of claims 1 to 1 1.

Images