JP2000052606A - Image-forming apparatus and its control method, and memory control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speed up an image formation process by reducing a quantity of data written to a memory for every recording scan at the execution of multipath recording. SOLUTION: A recording head 112 has nozzles corresponding to (h) pixels in a shuttle direction and can record an image of h×m pixels in one recording scan. Each memory block has at least a data capacity corresponding to image data of m×h/4 pixels. A head controller part 111 sequentially accesses four memory units among the memory blocks, reads out data by every h/4 pixels from each memory unit, thereby obtaining a sub scan directional data of (h) pixels. This is repeated by (m) times, whereby a data necessary for one recording scan is obtained. The read operation is carried out by changing an access order to the memory units for every recording scan. An image process part 103 writes in accordance with the access order new image data to memory units from which data are not read out yet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus and a control method thereof.

[0002]

2. Description of the Related Art Conventionally, there has been known an ink jet recording apparatus having a plurality of discharge holes and performing image recording by discharging ink droplets onto a recording material. In this ink jet recording apparatus, an image having a predetermined recording width is formed by reciprocating a recording head having a plurality of ink ejection holes relative to recording paper in a main scanning direction (recording scan). The whole image is formed by moving the recording material in the sub-scanning direction in synchronization.

In a general ink jet recording apparatus, print data input from a host computer is developed into an image, and the image is written into a buffer memory having a capacity for one recording scan. When the storage of the image data in the buffer memory is completed, the stored image data is sequentially read out, supplied to the print head, and the print scan is performed. When one print scan is completed, the contents of the buffer memory are updated with image data for the next print scan.

[0004]

However, in the above-described control procedure, writing and reading of image data to and from the buffer memory are performed in a time-division manner. For this reason, the sum of the print cycle by the print head (the time required for one print scan) and the write cycle for writing the image data for one print scan to the buffer memory is the actual print time for one print scan. . As described above, since the recording scan and the writing to the memory cannot be performed at the same time, the recording time becomes longer.

[0005] In the case of performing multi-pass printing in which image formation for one printing line is performed by a plurality of printing scans, the effect on printing time is particularly large. That is, in the case of multi-pass printing, for example, when printing is performed in four passes (four-pass mode), the paper is fed by a height of 1/4 of the height of the print head in the sub-scanning direction to perform print scanning. Do. Therefore, the data update in the buffer memory is performed four times as frequently as in the case of one pass, which significantly lowers the recording speed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made to reduce the amount of data written to a memory for each print scan and to speed up image forming processing when performing multi-pass printing. Aim.

[0007]

An image forming apparatus according to one embodiment of the present invention for achieving the above object has, for example, the following configuration. That is, a recording unit including a recording head capable of recording an image of m pixels in a scanning direction and h pixels in a sub-scanning direction orthogonal to the scanning direction in one recording scan. And at least mxh
Storage means including at least n memory units having a data capacity corresponding to image data of / n pixels;
The memory units are sequentially accessed, and data is read out by h / n pixels at a time from each memory unit to obtain data of h pixels in the sub-scanning direction, and this is repeated m times to provide data necessary for print scanning to the printing means. A reading unit, a control unit that repeats the reading unit while changing an access order to the memory unit in the storage unit for each recording scan, and a unit of the memory unit according to the access order controlled by the control unit. And writing means for writing new image data.

According to another aspect of the present invention, there is provided a method of controlling an image forming apparatus realized in the above-described image forming apparatus. According to still another aspect of the present invention, there is provided a memory control method suitable for use in the image forming apparatus. According to still another aspect of the present invention, there is provided a storage medium for storing a control program for causing a computer to execute the method for controlling the image forming apparatus.

[0009]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 18 is an external perspective view showing the outline of the configuration of the ink jet printer IJRA according to the present embodiment. In FIG. 18, the carriage HC that engages with the spiral groove 5004 of the lead screw 5005 that rotates through the driving force transmission gears 5009 to 5011 in conjunction with the forward and reverse rotation of the drive motor 5013 has a pin (not shown). And
It is reciprocated in the directions of arrows a and b supported by the guide rail 5003. On the carriage HC, an integrated type ink jet cartridge IJC containing a recording head IJH and an ink tank IT is mounted. A paper pressing plate 5002 presses the recording paper P against the platen 5000 in the moving direction of the carriage HC. 5007,5
Reference numeral 008 denotes a photocoupler, which is a lever 5006 of the carriage.
Is a home position detector for confirming the existence in this region and switching the rotation direction of the motor 5013. Reference numeral 5016 denotes a member that supports a cap member 5022 that caps the front surface of the recording head IJH. Reference numeral 5015 denotes a suction device that suctions the inside of the cap.
The suction recovery of the recording head is performed via 23. Reference numeral 5017 denotes a cleaning blade, and 5019, a member which allows the blade to move in the front-rear direction.
8, these are supported. It goes without saying that the blade is not limited to this form and a known cleaning blade can be applied to this example. Reference numeral 5021 denotes a lever for starting suction for recovery of suction. The lever 5021 moves with the movement of the cam 5020 that engages with the carriage, and the driving force from the driving motor is controlled by a known transmission mechanism such as clutch switching. Is done.

The capping, cleaning, and suction recovery are configured so that desired operations can be performed at the corresponding positions by the action of the lead screw 5005 when the carriage comes to the area on the home position side. If a desired operation is performed at the timing, any of the embodiments can be applied.

As described above, the ink tank IT and the recording head IJH may be integrally formed to constitute a replaceable ink cartridge IJC. However, the ink tank IT and the recording head IJH are separated. It may be configured so that only the ink tank IT can be replaced when the ink runs out.

FIG. 19 is an external perspective view showing the structure of an ink cartridge IJC in which an ink tank and a head can be separated. In the ink cartridge IJC, as shown at 23, the ink tank IT and the recording head IJH can be separated at the position of the boundary line K. Ink cartridge IJC
Is provided with an electrode (not shown) for receiving an electric signal supplied from the carriage HC side when this is mounted on the carriage HC, and the electric signal drives the recording head IJH as described above. Ink is ejected.

In FIG. 19, reference numeral 500 denotes an ink ejection port array. The ink tank IT is provided with a fibrous or porous ink absorber for holding ink, and the ink is held by the ink absorber.

In the above description, the droplets ejected from the recording head are described as ink, and the liquid contained in the ink tank is described as ink. However, the contained material is limited to ink. is not. For example, an ink tank may contain a processing liquid discharged to a recording medium in order to improve the fixability and water resistance of the recorded image or to improve the image quality.

FIG. 1 is a diagram showing an outline of a control configuration of the ink jet printer according to the present embodiment. In FIG. 1, reference numeral 101 denotes a system control unit that controls the overall operation of the printer, 102 denotes a host i / f unit that receives image data from a host PC (not shown), and 103 denotes a host PC.
An image processing unit 104 for converting image data from the image data into image data suitable for printing, and a DMAC 104 for controlling writing and reading addresses of the image data in a memory block
Unit, 105 to 110 are memory blocks for temporarily storing image data, 111 is a head controller unit for converting image data into a data format for sending to a print head,
Reference numeral 112 denotes a print head unit (including the above-described print head IJH); 113, a motor control unit that controls the operations of the motors 114 and 115; 114, a scan motor (corresponding to the above-described drive motor 5013) for performing a scan operation of the print head; And 115, a paper feed motor for feeding the recording paper.

First, a brief description will be given of multi-pass printing used in the present ink jet printer.

The recording head used in the present ink jet printer is provided with 256 ink ejection holes at intervals of 600 dpi so as to be able to process a plurality of dots simultaneously. The image data received from the host PC is multi-value data of 300 dpi, and the recording head prints one pixel with four dots. Each dot is 2
Since the value is a value, printing of 5 gradations is performed with 4 dots. The conversion from the multi-valued data to four dots and five gradations is performed by the head controller 111. In the present embodiment, ink ejection (recording) from each ejection hole can be executed in the following three modes.

That is, (1) one printing scan of the printing head is performed to print all data having a width of 256 dots (128 pixels).
Pass mode, (2) 1 in the first print scan of the print head
A two-pass mode in which a total of 256 dots are printed in a total of two printing scans, such as printing 28 dots (64 pixels) and printing the remaining 128 dots in the second printing scan; (3) first printing 64 dots (32 pixels) are recorded in the recording scan of the recording head, and 64 different dots are recorded in the second recording scan, and different 64 dots are recorded in the third and fourth recordings. 2 times in the recording scan
This is a 4-pass mode in which printing is performed with a width of 56 dots.

The two-pass mode and the four-pass mode are processes performed to absorb print density unevenness caused by variations in the output characteristics of the discharge nozzles. The principle thereof is known, and a detailed description thereof will be omitted here. .

Next, an outline of the flow of image data of the ink jet printer according to the present embodiment will be described with reference to FIG.

300 generated by the host PC (not shown)
The image data of dpi is first transferred to the image processing unit 103 via the host i / f unit 102. Image processing unit 103
Converts the data format of the image data from the host PC into an image format suitable for the characteristics of the ink colors used in the inkjet printer.

The image data converted by the image processing unit 103 is stored in the 0th memory block 105 to the 5th memory block 1
10 sequentially. Each memory block 105-11
0 stores image data of 32 lines each corresponding to a 64 dot width. Then, the 0th memory block 1
05 → first memory block 106 →... → fifth memory block 110 → 0th memory block 105 →... Used as a ring buffer type data buffer, and image data of up to 192 lines (32 lines × 6) To accumulate.

The head controller 111 reads out image data corresponding to 128 lines corresponding to a 256-dot recording width to be recorded in one recording scan by the recording head 112 from the corresponding memory block. For example, data of 1 to 32 lines is read from the 0th memory block 105,
33-64 lines of data are read from the first memory block 106, and 65-9 are read from the second memory block 107.
Six lines of data are read out, and the third memory block 10 is read.
Data of 8 to 97 to 128 lines are read.

In the case of the one-pass mode, the head controller 111 sends the read image data for 128 lines to the recording head 112 as it is, and records all the image data having a width of 256 dots.

In the case of the two-pass mode, the head controller unit 111 adds 1/1 to the read data of 128 lines.
The image data with the mask 2 (to be described later with reference to FIG. 7) is sent to the recording head 112. As a result, in one printing scan, pixels having half the total number of dots are printed.

In the case of the 4-pass mode, the head controller unit 111 converts the read data of 128 lines by 1 /.
The image data with the mask of No. 4 (to be described later with reference to FIG. 8) is sent to the recording head 112. As a result, in one print scan, pixels having a dot number of 1/4 of the total dot number are printed.

The motor controller 113 controls the operation of the scan motor 114 in order to scan the recording head 112 in synchronization with the image data read timing of the head controller 111. Also, the motor control unit 113
Controls the operation of the paper feed motor 115 in order to feed the recording paper every time the scan of the recording head 112 is completed.

The system controller 101 controls the host I / F 102, the image processor 103, the DMAC 104, the head controller 111, and the motor controller 113 described above.

FIG. 2 is a block diagram showing the configuration of the host i / f unit. Hereinafter, with reference to FIG.
2 will be described in detail.

The host i / f 102 includes a selector 201,
Command FIFO 202, status FIFO 203,
It has a data FIFO 204. The FIFO means a first-in first-out memory.

A command FIFO 202 is a FIFO port for receiving a control command from the host PC to the inkjet printer. The received control command is read by the system control unit 101. Here, the control command includes a transfer start notification and a transfer end notification of image data,
This is operation control of the entire printer operation, such as the size of image data.

A status FIFO 203 is a FIFO port for transmitting a control status from the inkjet printer to the host PC. The control status is written by the system control unit 101. Here, the control status is a notification of completion of reception of image data, a notification of a recording status, an error notification, and the like.

A data FIFO 203 is a FIFO port for receiving image data sent from the host PC.
The received image data is transferred to the image processing unit 103.
This image data is to be recorded by the inkjet printer.

The selector 201 is controlled by the host PC, and switches the connection between each FIFO and the host PC.
That is, the selector 201 connects the data path (data path) to the command FIFO 202 when the host PC writes the control command, and connects the data path to the status FIFO 2 when the host PC reads the control status.
When the host PC writes image data, the data path is connected to the data FIFO 204.

FIG. 3 is a block diagram showing the configuration of the image processing unit in the ink jet printer of the present embodiment.
Hereinafter, the configuration of the image processing unit 103 will be described with reference to FIG.

The image processing unit 103 includes a color conversion unit 301, L
It comprises a UT (Look Up Table) 302, an ED processing unit 303, and a path switching unit (304 to 307).

The color conversion unit 301 converts the format of the image data sent from the host PC into a format that matches the ink characteristics of the inkjet printer. Data conversion is realized by referring to the LUT 302. The LUT 302 can be rewritten by the system control unit 101, and is configured so that the LUT can be rewritten according to a control command issued from the host PC.

The ED processing unit 303 performs an error diffusion process on the image data received from the host PC. In the present embodiment, the image data from the host PC is 300 dpi-25
6 gradations (8 bits), and the resolution of the printhead is 6
The description will be made assuming that the resolution is 00 dpi-2 gradation (1 bit). Since the recording head has two gradations (1 bit), the 300 dpi image data received from the host PC is the same as that shown in FIG.
As shown in FIG. 6, each pixel corresponds to an ink droplet of 4 dots. Since a maximum of five gradations can be expressed by a four-dot ink droplet, the original 256-gradation data loses gradation information as it is. The ED processing unit 303 performs a process of diffusing the error due to the gradation lowering to the peripheral pixels and storing the gradation in the entire image. The data output from the ED processing unit is 3 bits (5 gradations).

The path switching 304 and the path switching 305 are
It is determined whether to bypass the color conversion unit 301. This path switching is performed according to a control command received by the system control unit 101 from the host PC. The path switching 306 and the path switching 307 are provided by the ED processing unit 303.
Is to be bypassed. This path switching also
The processing is performed by the system control unit 101 according to the control command received from the host PC.

Next, the configuration of the memory block will be described. FIG. 4 is a block diagram illustrating a configuration of a memory block of the inkjet printer according to the present embodiment. In the following, the 0th memory block 105 will be described, but the first to fifth memory blocks 106 to 110 have the same configuration.

The 0th memory block 105 includes the DRAM 4
01, data bus gates 402 and 403, address bus gates 404 and 405, and an AND gate 406.

The DRAM 401 has a 4 × 1 Mbits configuration, and has a 10-bit address bus input [A9-
A0], 4-bit data bus input / output [D3-D
0], write enable signal input WE, read enable signal OE, row address input signal RA
S and a column address input signal CAS.

When writing to the DRAM 401, WR-
Since enable 415 becomes valid, the address bus
Gate 404 and data bus gate 402 become active. Therefore, the address of WR-ADR 414 is DR
While being input to the AM 401, the data of Din 410 is input to the DRAM 401, and the data is written.

On the other hand, when reading from the DRAM 401, the RD-enable 413 becomes valid, so that the address bus gate 405 becomes active. Therefore, R
According to the address of the D-ADR 412, the DRAM 401
Is output to the data bus 419. In this state, when the RD-sel signal 418 becomes valid, AND
The output of the gate 406 becomes valid, the data bus gate 403 becomes active, and the data output to the data bus 419 is output to the data bus 411. That is, according to the RD-sel signal (418), D
The read data is output to out411.

FIG. 5 is a diagram showing the connection state between the DMAC unit 104 and each memory block in detail. Image data 501 from the image processing unit 103 is connected to a Din input of each memory block via a bus. An address output from the DMAC unit 104 is connected to each WR-ADR and each RD-ADR via a bus. D from each memory block
The out output is connected to the bus and the head controller 11
1 is image data 502. The WR-enable signal, RD-enable signal, RAS signal, CAS signal, and RD-sel signal of each memory block are independent for each memory block.
04, and is controlled to realize the control described with reference to the attached flowchart.

FIG. 6 is a block diagram for explaining the structure of the head controller 111. As shown in FIG. 6, the head controller unit 111 includes a mask pattern generation unit 60.
1 and a mask gate 602 and a binarization unit 605.

The mask pattern generator 601 is controlled by the system controller 101. System control unit 1
01 indicates that the inkjet printer is in one-pass mode, two-pass mode,
It determines which of the four-pass modes to operate, and controls the mask pattern generator 601 according to the determined mode. Further, the mask gate 602 stores the image data 502 (601) from the memory block and the mask pattern generation unit 6
The signal is ANDed with the signal from No. 01, and the result is output to the binarization unit 605. The binarizing unit 605 converts the 300 dpi 5-value data from the memory block into 600 dpi 2-value dot data and outputs the dot data to the ejection head.

The outline of the operation of the mask pattern generation unit 601 in each of the one-pass mode, the two-pass mode, and the four-pass mode is as follows.

In the one-pass mode, the signal from the mask pattern generator 601 to the mask gate 602 is always valid, and the mask gate 602 is always on. All the image data 603 from the memory block
05.

In the two-pass mode, the mask gate 60
2 is turned on at 50% duty, and the image data 603 from the memory block is thinned out to 1/2 and sent to the binarizing unit 605.

In the 4-pass mode, the mask gate 60
2 is turned on at 25% duty, and the image data 603 from the memory block is thinned out to 1/4 and sent to the binarization unit 605.

Here, the mask processing in the head controller 111 will be described in more detail. 7 to 10
A detailed description will be given with reference to FIG. FIG. 7 is a diagram showing an example of a mask pattern in the two-pass mode. FIG. 8 is a diagram showing an example of a mask pattern in the 4-pass mode. FIG. 9 is a view for explaining the arrangement of print pixels in each printing pass when printing is performed in the two-pass mode using the mask pattern shown in FIG. FIG. 10 is a diagram illustrating the arrangement of print pixels in each print pass when printing is performed in the 4-pass mode. 9 and 10 are views showing a part of the recording area. In practice, this pattern is repeated in the number of pixels corresponding to the recording width in the horizontal direction and 128 pixels in the vertical direction. Further, n is an integer.

In the above-described two-pass mode, １ ／ thinning is performed.
The 4 × 4 matrix shown in FIGS. 7 and 8 is used for 1/4 thinning in the 4-pass mode. This matrix represents 4 × 4 pixels in units of recording pixels, and masks the data of the pixels painted black.

In the two-pass mode, first, in the (2n + 1) -th scan, the head controller 111 masks the image data read from the memory block using the mask pattern shown in FIG. Value conversion unit 6
The recording data is sent to the recording head 112 via the recording head 05. (A) of FIG. 9 shows a state where recording was performed in the (2n + 1) -th scan. Here, the recording data corresponding to the pixel described with the number “1” is recorded. No recording is performed for the other pixels. Note that one pixel is recorded with ink droplets of a maximum of four dots.

Next, in the (2n + 2) -th scan, the image data read from the memory block is masked using the mask pattern shown in FIG.
The recording data is sent to the recording head (112) through the recording head (05). (B) of FIG. 9 illustrates a state where recording is performed in the (2n + 2) -th scan. The recording data corresponding to the pixel described with the number “2” is recorded.

The (2n + 1) -th scan and the (2n + 1) -th scan
During the (n + 2) -th scan, paper feeding of 64 pixels (128 dots) corresponding to a half shuttle is performed, so that printing is performed with the number of lines shifted by a half shuttle. In the (2n + 1) -th scan and the (2n + 2) -th scan, the shift of each half shuttle is repeated, so that all pixels are recorded as a whole.

In the case of the 4-pass mode, (4n + 1)
In the second scan, the head controller 111
The image data read from the memory block is masked using the mask pattern shown in FIG. 8A, and the print data is sent to the print head 112 via the binarization unit 605. (A) of FIG. 10 shows a state where recording is performed in the (4n + 1) -th scan. Recording data corresponding to the pixel described with the number “1” is recorded. No recording is performed on the other pixels.

Similarly, in the (4n + 2) -th scan, the image data read from the memory block is masked using the mask pattern shown in FIG. 8B, and is applied to the recording head 112 via the binarization unit 605. Send recorded data.
FIG. 10B shows a state where recording is performed in the (4n + 2) -th scan. In this scan, recording data corresponding to the pixel described with the number “2” is recorded.

In the (4n + 3) -th scan, the image data read from the memory block is masked using the mask pattern shown in FIG.
The recording data is sent to the recording head 112 via the. FIG.
(C) shows the state recorded in the (4n + 3) -th scan. In this scan, recording data corresponding to the pixel described with the number “3” is recorded.

Further, in the (4n + 4) -th scan,
The image data read from the memory block is masked using the mask pattern shown in FIG. 8D, and the print data is sent to the print head 112 via the binarization unit 605.
(D) of FIG. 10 shows a state where recording was performed in the (4n + 4) -th scan. The recording data corresponding to the pixel described with the number “3” is recorded.

In the case of the 4-pass mode, a paper feed of 32 pixels (64 dots) corresponding to a 1/4 shuttle is performed between each scan, so that the number of lines is shifted by 1/4 shuttle. Recording is performed in the state. Since each scan is repeatedly shifted by 1/4 shuttle, all pixels are recorded as a whole.

The recording head 112 has 256 ejection holes at a density of 600 / inch. By scanning the head in the raster direction, the recording head 112 has a density of 600 dpi.
Pixels of up to 128 lines per recording scan (300 dp
i) Recording is possible. Hereinafter, the direction in which the ejection holes of the recording head 112 are arranged is referred to as a shuttle direction.

In this ink jet printer, the host P
In the image data from C, 300 dpi pixel data is transferred line by line in the raster order. On the other hand, 128 pixels arranged in the shuttle direction are transferred from the image data of 128 lines output from the image processing unit 103 to the head controller unit 111. That is, in the 0th memory block 105 to the fifth memory block 110,
A function of converting the order of image data is realized. Hereinafter, the memory block according to the present embodiment will be described in more detail.

First, the memory block 105 of the present embodiment
To 110 will be described. FIG. 11 is a diagram for explaining the address space of each memory block. FIG. 12 is a diagram illustrating address assignment to memory blocks according to the present embodiment.

DRAM 401 in each memory block
Has an address space of a total of 20 bits with a row address of 10 bits and a column address of 10 bits. The address space of 19 bits is first divided into A18 to A5 of upper 13 bits and A18 of lower 5 bits.
4 to A0 to form a two-dimensional address space as shown in FIG. The most significant address bit is fixed to 0.

Next, the numbers of the respective memory blocks are represented by A21 to A21.
A configuration is made as shown in FIG. 12 corresponding to the value represented by 3 bits of A19. Note that the number of pixels represented by [A4-A0] is the number of pixels in the shuttle direction in the single memory block (hereinafter, the first number of pixels n), and [A18-A0].
A5] is the number of pixels in the scanning direction (hereinafter, the second number of pixels N). With this configuration, three address counters, [A21-A19],
With [A18-A5] and [A4-A0], the address space of each memory block can be uniquely managed and generated.

In the address space shown in FIGS. 11 and 12, the address axes A18 to A5 correspond to the scan direction of the print head, that is, the raster direction of the print image, and A2 to A5.
1-A19 and A4-A0 correspond to the shuttle direction of the print head, that is, the paper feed direction of the print image.

In FIG. 11, the address in the shuttle direction is composed of 5 bits of A4-A0 because the number of pixels to be recorded by the recording head 112 is 2 or 4 in the recording mode.
Divided by 4 which is the least common multiple of, that is, 32 (= 12
This is for dividing one memory block in the shuttle direction by the number of pixels of 8/4). In the case of the present embodiment, the number of pixels in the shuttle direction of the recording head (hereinafter, the third number of pixels m) is 128 for four blocks.

The address space allocation described above will be further described.

Assuming that the number of pixels recorded by the recording head is h, in the case of recording in the two-pass mode, h
The paper is advanced by / 2 pixels. Similarly, when printing in the 4-pass mode, paper is fed by h / 4 pixels for each scan. Therefore, the value of h needs to be a value divisible by “4” which is the least common multiple of “2” and “4” in the recording mode.

The “value obtained by dividing h by the least common multiple” is j, and the memory space in the shuttle direction for each memory block is j ′. When j is a power of 2, the memory space in the shuttle direction of the memory block is j (j ′ =
j). When j is not a power of 2, j is a power of 2 and a value larger than j is j '. In this case, the memory space corresponding to (j'-j) is unused. Therefore, j 'is preferably selected to be the smallest of the applicable powers of two.

To explain in a concrete example, when the number of ejection holes of the recording head is 256, since the number of pixels to be recorded is 128, j
= 32. Since 32 is 2 to the fifth power, j ′ = 32. On the other hand, when the number of ejection holes of the recording head is 240, j = 30. Because 30 is not a power of 2,
j ′ = 32.

The number of memory blocks is as follows. When writing and reading to the memory block are sequentially performed at different timings, the address space in the shuttle direction of the memory block is set to a value that satisfies the number of pixels recorded by the recording head. In the above example, a value obtained by multiplying the maximum and least common multiple “4” by j ′ may be used. On the other hand, when writing and reading to and from the memory block are performed simultaneously in parallel, a space corresponding to the number of pixels to be fed in one scan is added to the memory space in the shuttle direction. For example, if you want to implement simultaneous reading and writing in 4-pass mode,
A memory space of (128/4) × N (N is the number of pixels in the scan direction) is added in the shuttle direction. Specifically, one memory block is added. In addition, if simultaneous read / write processing is performed in the two-pass mode, it is necessary to add (128/2) × N memory space in the shuttle direction. Specifically, two memory blocks must be added. become. Further, if simultaneous read / write processing is performed even in the one-pass mode, it is necessary to add four memory blocks.

In the case of the present embodiment, it is configured to enable simultaneous processing in the 4-pass mode and the 2-pass mode. A memory space for 64 pixels, which is the larger of the number of paper feed pixels (128/2) in the two-pass mode and the number of paper feed pixels (128/4) in the four passes, is added in the shuttle direction. Therefore, a memory space for 192 pixels obtained by adding 64 to 128 for the number of recording pixels of the recording head, that is, six memory blocks are arranged in the shuttle direction, and configured as shown in FIG.

As described above, if the address space in the shuttle direction is a power of 2, the address space in the raster direction of the image and the address space in the shuttle direction can be managed by different address bits.

In the case of this embodiment, the address of the shuttle direction of each memory block is managed by 5 bits of [A4-A0] and the raster direction is managed by 14 bits of [A18-A5].
6 memory blocks are divided into 3 bits of [A21-A19].
Manage with s.

The DMAC 104 independently performs [A21-A19] and [A18] for writing and reading, respectively.
-A5] and [A4-A0]. When writing the image data to the memory block, since the data from the host PC is sent in the order of the image data in the raster direction, [A18-
A5] is accessed by counting up the address counter.

On the other hand, when the image data is read from the memory block, since the ejection holes of the recording head are arranged in the shuttle direction, the address counters [A4-A0] and [A21-A19] are counted up. to access.

The operation of the ink jet printer according to the present embodiment, mainly for memory access, will be described.

FIG. 13 is a flowchart for explaining a procedure for controlling access to the memory block during the image recording operation of the ink jet printer according to the present embodiment.

First, the ink jet printer first sets a mode (step S1). In the mode setting,
According to the control information from the host PC written in the command FIFO 202 of the host i / f 102, setting of a recording mode (one of a one-pass mode, two-pass mode, and four-pass mode) and setting of path switching of the image processing unit 103 , L
The UT 302 is rewritten.

Next, the memory block is initialized (step S2). In the initialization of the memory block, in the 2-pass mode or the 4-pass mode, in order to avoid shortage of the recording duty near the top line of the recording page,
Dummy data is written in the first two blocks in the pass mode and in the first three blocks in the four-pass mode.

FIG. 14 is a flowchart for explaining the memory block initialization processing. In the initialization of the memory block, it is first determined whether or not the recording mode is the 4-pass mode (step S11). Initialization (step S12). In the initialization of data, dummy data in which nothing is recorded, usually a data value corresponding to white, is written in the corresponding memory block. When the initialization of the memory block is completed, 3 is set to the value of the parameter “WRStartBlock”, and the process ends (step S13). The parameter “WRStartBlock” is a parameter indicating which memory block to write data transferred from the host PC (described later with reference to the flowchart of FIG. 15).

If the printing mode is not the 4-pass mode, it is determined whether the printing mode is the 2-pass mode (step S1).
4) In the case of the two-pass mode, the 0th memory block 105
And the first memory block 106 are initialized in the same manner as described above (step S15). After the initialization of the memory block (step S15), the parameter “WRStartBlock”
Is set to 2 (step S16), and this processing ends.

When the recording mode is not the two-pass mode, it is determined that the mode is the one-pass mode, and the parameter "WRStar" is set.
“0” is set to “tBlock” (step S17), and this processing ends.

When the initialization of the memory block is completed (step S2) as described above, the transfer of image data is permitted to the host PC, and the transfer of image data from the host PC is started (step S3). ). That is, the system control unit 101 sets the status FIFO 203
The host PC notifies the host PC of transfer permission as status information via the host PC, and the host PC starts transfer of image data according to the status information.

When the image data is transferred from the host, the state of the data FIFO 204 becomes the noempty state. This n
In response to the oempty state, the DMAC 104 is activated, and a process of writing image data to a memory block via the image processing unit 103 is started (step S4). Image data write processing is performed in parallel with other processing until image data transfer from the host PC ends. The process of writing image data to the memory block will be described later with reference to FIG.

Next, the image data from the host PC is transmitted to the third
When the transfer to the memory block 108 is completed, it is determined that the transfer of the image data for one band necessary for the recording scan has been completed (step S5), and subsequently, the reading process of the image data from the memory block is started (step S6).
Image data read processing is also performed in parallel with other processing until the read processing from the memory block is completed. The process of reading image data from the memory block will be described later with reference to FIG.

As described above, the processing of writing image data into the memory block started in step S4 and the processing of reading image data started in step S6 are performed in parallel. When the transfer of the image data from the host PC is completed (step S7), "WRData
By setting the "End" flag, the writing process to the memory block is completed (step S8), and the dummy data is written to the memory block instead of the image data (step S9). It is the same value as the data value written in the conversion (step S2).

When the reading of the image data from the memory block is completed (step S10), the recording operation of the ink jet printer is completed.

Next, the process of writing image data to a memory block will be described. FIG. 15 is a flowchart illustrating a process of writing image data to a memory block.

First, the write address of the DMAC unit 104 is initialized (step S21). The write address is an address corresponding to the WR-ADR signal in FIG. As described above, the address is [WA21-W
A0], three counters are prepared to represent this address, and [WA21-WA19],
[WA18-WA9] and [WA8-WA0]. Then, [WA18-WA9] is output as a row address at the RAS timing, and [WA8-WA9] is output at the CAS timing.
-WA0] as a column address. [WA
21-WA0], the pixel data in the memory space indicated by the value of
The same pixel data is shown in the memory space of [A21-A0] in FIGS. The initialization value is [WA21-
[WA19] is set to the value of the parameter "WRStartBlock", and [WA18-WA5] and [WA4-WA0] are set to 0.

Next, a process of writing image data in the raster direction (steps S22 to S26) is executed. The process of writing image data in the raster direction
The process is repeatedly executed until the data transfer for one line is completed (step S27).

In the process of writing image data in the raster direction, first, image data from the host PC is written in the memory space indicated by the write address [WA21-WA0] (step S22). Here, when the image data from the host PC is lost and the transfer of the image data from the host is completed (step S23), writing of dummy data is set instead of the image data (step S24).
The "WRDataEnd" flag is set (step S25). This dummy data write setting (step S2
4) corresponds to the above-described dummy data write processing (step S9).

Then, the write address [WA18-W
A5] is incremented by one (step S26). When the data transfer for one line in the raster direction is completed (step S27), the write address [WA1
8-WA5] is reset to 0 (step S28),
[WA4-WA0] is counted up by +1 (step S
29)

The above processing (steps S22 to S22)
29) is repeated the number of times indicated by j above. When the value of j matches the number of repetitions, it is determined that the transfer in one memory block has been completed (step S30).

When one memory block transfer is completed (step S30), the write address [WA21-WA]
19] is incremented by +1 and the next memory block is selected (step S31).

Here, as a result of counting up, [WA
21-WA19] = 6h (step S32),
Since this memory block is a ring buffer of 0-5,
The value of [WA21-WA19] is reset to 0 (step S33).

When the next memory block is selected, it is checked whether or not the selected memory block is being read by the image data reading process started in step S6.
If the reading is being performed, the process waits until the reading is completed (step S34).

When the reading is completed, "WRDataEn
The "d" flag is checked (step S35), and if the "WRDataEnd" flag is not set, the write processing of the memory block (steps S22 to S33) is repeated, and if the "WRDataEnd" flag is detected, this processing ends.

Next, a process of reading image data from a memory block will be described. FIG. 16 is a flowchart illustrating the procedure of the image data reading process according to the present embodiment.

First, a read address of the DMAC unit 104 is initialized (step S41). The read address is an address corresponding to the RD-ADR signal in FIG. This read address [RA21-RA0]
Are prepared and [RA21-RA19], [RA18-RA9], and [R
A8-RA0]. Then, [RA18-RA9] is output as a row address at the RAS timing,
At the CAS timing, [RA8-RA0] is output as a column address. The pixel data in the memory space indicated by the value of [RA21-RA0] is [A2 in FIG. 11 and FIG.
1-A0]. In this initialization process, [RA21-RA19], [R21
A18-RA5] and [RA4-RA0] respectively.
Is set.

Subsequently, 0 is set in the parameter “RDStartBlock”.
Is set, and 3 is set in “RDEndBlock” to perform initialization (step S42). RDStartBlock = 0, RDEndBlo
When ck = 3, data is read from the 0th memory block to the third memory block.

Next, a process of reading image data for one memory block in the shuttle direction (steps S43 to S45) is performed. First, one pixel is read (step S4
3) is executed, and the read address [RA4-RA0] is incremented by +1 (46). [RA4-RA0]
When the result of counting up by 1 is equal to the value of j (step S45), it is determined that the shuttle direction reading of one memory block has been completed, and [RA4-RA0] is set to 0.
(Step S46) and DMAC
104 read address [RA21-RA19]
One is counted up (step S47) and the next memory block is selected.

Here, as a result of counting up, [RA
21-RA19] = 6h (step S4
In 8), since the memory block of this embodiment is a ring buffer of 0 to 5, the value of [RA21-RA19] is reset to 0 (step S49).

The above-described image data reading process in the shuttle direction (steps S43 to S49) is performed by setting the read address [RA21-RA19] to the parameter “RDEndB”.
The process is repeated until the value matches the value of "lock" (step S50), and image data for the recording width of the recording head is read.

Read address [RA21-RA19]
Matches the value of the parameter “RDEndBlock” (step S5
0), the read address [RA21-RA1] is read in order to read the next one row of image data in the shuttle direction.
9] is set to the value of the parameter “RDStartBlock” (step S51), and the read address [RA18-
RA5] is incremented by one (step S52).
I do.

The above processing (steps S43 to S52) is repeated until the result of incrementing the read address [RA18-RA5] by +1 reaches the line end in the raster direction (step S53).

When the result of incrementing the read address [RA18-RA5] by +1 reaches the line end in the raster direction (step S53), the 0th to the 3rd is executed.
This means that reading in the memory block has been completed. Therefore, in order to perform reading for the next memory block group, the read address [RA18-RA
5] is reset to 0 (step S54), and the next read memory block is selected (step S55).

Here, the process of selecting the next memory block (step S55) will be described in detail. FIG. 17 is a flowchart illustrating the procedure of the next memory block selection process.

First, it is determined whether or not the recording mode is the 4-pass mode. If the recording mode is the 4-pass mode (step S61), the values of the parameters “RDStartBlock” and “RDEndBlock” are set to 1 if 0, and 1 if 1, respectively. The number is set to 2, 2 to 3, 3 to 4, 4 to 5, 5 to 0, and advances by one memory block (step S63). Therefore, in the 4-pass mode, for example, when the reading process of the 0th memory block to the 3rd memory block is completed, the next memory block is the 1st memory block to the 4th memory block.

If the recording mode is the two-pass mode (step S62), the parameter "RDStartBlock"
And the value of “RDEndBlock” are set to 2 for 0, 4 for 2 and 4
If this is the case, it is set to 0 and the processing is advanced by two memory blocks (step S64). Therefore, in the two-pass mode, for example,
When the reading process of the memory block to the third memory block is completed, the next memory block is changed to the second memory block to the third memory block.
This is the fifth memory block.

When the mode is neither the 4-pass mode nor the 2-pass mode, the mode is the 1-pass mode.
k ”and“ RDEndBlock ”values are 4 for 0, 0 for 2
On the other hand, if the number is 4, the number is set to 2 and the processing advances by 4 memory blocks (step S65). Therefore, in the one-pass mode, for example, when the read processing of the 0th memory block to the 3rd memory block is completed, the next memory blocks are the 4th, 5th, 0th, and 1st memory blocks.

After the above-described next memory block selection processing (step S55), it is checked whether or not the selected memory block is being written (step S55).
56). If the writing is being performed, the process waits until the writing is completed.

The above processing (from step S43 to step S43)
56) is repeated until all the image data transferred from the host PC is read out, and when all the image data are read out (step S57), the process of reading out the image data from the present memory block ends.

As described above, according to this embodiment, a memory space corresponding to the amount of feed in the shuttle direction for each print scan in multi-pass mode printing is allocated to a single memory block, and Data can be read and written independently. Therefore, even in printing in the multi-pass mode, it is not necessary to rewrite the memory space for one printing scan, and the printing time is shortened.

Further, by having a memory block extra than the memory space for one recording scan, data writing to the memory and data reading from the memory can be processed in parallel, so that the processing time can be further reduced. .

In the above embodiment, the case where the recording color is one color has been described. However, the present invention can also be applied to a color ink jet recording apparatus that performs color recording with a plurality of colors. In the case of a color inkjet recording apparatus, the DMAC 104 and the 0th memory block 105 shown in the above embodiment are used.
The configuration of the fifth to fifth memory blocks 110 may be configured in parallel for a required number of colors.

In the above embodiment, the two-pass mode and the four-pass mode
Although the description has been given of the case of the ink jet printing apparatus corresponding to the pass mode, in the case where only the two-pass mode is supported, the memory block may be composed of three blocks. However, one memory block is a memory space having an address space width of 64 pixels in the shuttle direction.

Further, when corresponding to three types of multi-pass modes, that is, a 2-pass mode, a 4-pass mode, and an 8-pass mode, it is sufficient to configure the memory block with 12 memory blocks. However, in this case, 256 dots (128
When a recording head of (pixels) is used, one memory block becomes a memory space having a data width of 128/8 = 16 pixels in the shuttle direction.

The memory in the memory block may be constituted not only by one DRAM but also by a plurality of DRAMs, and may be constituted by an SRAM.

In the above embodiment, each address is 4
Since a memory having a bit depth is used, not only 3-bit quinary image data but also 4-bit multi-value image data can be stored. Further, if binary data is received from the host PC without performing the ED process, 4-bit data read from one address may directly correspond to four dots forming one pixel. Good. However, in this case, the binarization unit 605 of the head controller unit 111 is bypassed.

In the above embodiment, an example was described in which an ink jet printer having a plurality of ejection holes and performing image recording by ejecting ink droplets on a recording material was applied.
It goes without saying that the present invention can be applied to other printers such as a thermal recording system.

The above-described embodiment is particularly provided with a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for performing ink ejection even in an ink jet recording system. By using a method in which a change in the state of the ink is caused by energy, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method can be applied to both the so-called on-demand type and the continuous type.
By applying at least one drive signal corresponding to the recorded information and providing a rapid temperature rise exceeding the film boiling to the electrothermal transducer arranged corresponding to the sheet or the liquid path holding the Since thermal energy is generated in the electrothermal transducer and film boiling occurs on the heat-acting surface of the recording head, bubbles in the liquid (ink) corresponding to this drive signal on a one-to-one basis can be formed. It is valid. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of the liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable.

As the pulse-shaped driving signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angle liquid flow path) as disclosed in the above-mentioned respective specifications, A configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600, which discloses a configuration in which a heat acting surface is arranged in a bent region, is also included in the present invention. In addition, for multiple electrothermal transducers,
JP-A-59-123670 which discloses a configuration in which a common slot is used as a discharge part of an electrothermal transducer, and JP-A-59-123670 which discloses a configuration in which an opening for absorbing a pressure wave of thermal energy corresponds to a discharge part. A configuration based on 138461 may be adopted.

Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length is determined by a combination of a plurality of recording heads as disclosed in the above specification. This may be either a configuration satisfying the above requirements or a configuration as a single recording head formed integrally.

In addition to the cartridge type recording head in which an ink tank is provided integrally with the recording head itself described in the above embodiment, the recording head is electrically connected to the apparatus main body by being mounted on the apparatus main body. A replaceable chip-type recording head, which enables a simple connection and supply of ink from the apparatus main body, may be used.

It is preferable to add recovery means for the printhead, preliminary auxiliary means, and the like to the configuration of the printing apparatus described above, since the printing operation can be further stabilized. Specific examples thereof include capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer or another heating element or a combination thereof. It is also effective to provide a preliminary ejection mode for performing ejection that is different from printing, in order to perform stable printing.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, and may be a single recording head or a combination of plural recording heads. Alternatively, the apparatus may be provided with at least one of full colors by color mixture.

In the embodiment described above, the description is made on the assumption that the ink is a liquid. However, even if the ink solidifies at room temperature or lower, it is possible to use an ink that softens or liquefies at room temperature. Or, in the ink jet method, generally, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range.
It is sufficient that the ink is in a liquid state when the use recording signal is applied.

In addition, in order to positively prevent temperature rise due to thermal energy as energy for changing the state of the ink from the solid state to the liquid state, the temperature is positively prevented.
Alternatively, in order to prevent evaporation of the ink, an ink which solidifies in a standing state and liquefies by heating may be used. In any case, the application of heat energy causes the ink to be liquefied by application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start to solidify when reaching the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, as described in JP-A-54-56847 or JP-A-60-71260, the ink is held in a liquid state or a solid state in the concave portion or through hole of the porous sheet. It is good also as a form which opposes an electrothermal transducer. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition to the above, the recording apparatus according to the present invention may be provided not only as an image output terminal of an information processing apparatus such as a computer but also integrally or separately, a copying apparatus combined with a reader, etc. It may take the form of a facsimile machine having functions.

Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine, a facsimile, etc.) comprising one device Device).

Further, an object of the present invention is to provide a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (or CPU) of the system or apparatus.
And MPU) read and execute the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided on a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instructions of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0142]

As described above, according to the present invention,
When performing multi-pass printing, the amount of data written to the memory for each printing scan is reduced, so that the speed of image forming processing is increased.

[0143]

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an outline of a control configuration of an inkjet printer according to an embodiment.

FIG. 2 is a block diagram illustrating a configuration of a host i / f unit.

FIG. 3 is a block diagram illustrating a configuration of an image processing unit in the inkjet printer according to the embodiment.

FIG. 4 is a block diagram illustrating a configuration of an ink jet printer memory block according to the present embodiment.

FIG. 5 is a diagram showing in detail a connection state between a DMAC unit 104 and each memory block.

FIG. 6 is a block diagram illustrating a configuration of a head controller unit 111.

FIG. 7 is a diagram illustrating an example of a mask pattern in a two-pass mode.

FIG. 8 is a diagram illustrating an example of a mask pattern in a 4-pass mode.

9 is a diagram illustrating the arrangement of dots used in each printing pass when printing is performed in the two-pass mode using the mask pattern shown in FIG. 7;

FIG. 10 is a diagram illustrating the arrangement of used dots in each printing pass when printing is performed in the 4-pass mode.

FIG. 11 is a diagram illustrating an address space of each memory block.

FIG. 12 is a diagram illustrating address assignment to a memory block according to the present embodiment.

FIG. 13 is a flowchart illustrating a procedure for controlling access to a memory block during an image recording operation of the inkjet printer according to the present embodiment.

FIG. 14 is a flowchart illustrating a memory block initialization process.

FIG. 15 is a flowchart illustrating a process of writing image data to a memory block.

FIG. 16 is a flowchart showing a procedure of image data read processing according to the present embodiment.

FIG. 17 is a flowchart illustrating a procedure of a next memory block selection process.

FIG. 18 is an inkjet printer I according to the present embodiment.
It is an external appearance perspective view which shows the outline of a structure of JRA.

FIG. 19 is an external perspective view illustrating a configuration of an ink cartridge IJC in which an ink tank and a head are separable.

FIG. 20 is a diagram illustrating the relationship between multi-valued pixels and print dots.

Claims (21)

[Claims] 1. A recording head capable of recording an image of m pixels in a scanning direction and h pixels in a sub-scanning direction orthogonal to the scanning direction in one recording scan, wherein pixels are formed by one or a plurality of dots. Recording means provided; storage means including at least n memory units having a data capacity equivalent to image data of at least m × h / n pixels; and n memory units sequentially accessed, and Reading means for reading out data by n pixels at a time and sub-scanning direction data of h pixels, and repeating this for m times to provide data necessary for printing scan to the printing means; A control unit that repeats the reading unit while changing an access order to the memory unit; and a unit of the memory unit according to the access order controlled by the control unit. And a writing unit for writing new image data. 2. An n-pass mode in which printing is performed by shifting the printing position by h / n pixels in the sub-scanning direction in the sub-scanning direction for each printing scan, so that printing is completed by n printing scans of the print head. The image forming apparatus according to claim 1, further comprising a recording control unit that controls the recording unit to perform the recording of the image. 3. The printing control unit according to claim 1, wherein the printing control unit performs printing scanning while shifting a printing position by h / (n ÷ a) pixels in the sub-scanning direction for each printing scan, so that the printing head performs n / a times. 3. An apparatus according to claim 2, wherein printing can be performed in an n / a pass mode in which printing is completed by the printing scan of (a), and the control unit changes the access order in units of a memory units. Image forming device. 4. The storage unit includes more than n memory units, and writes new image data by the writing unit to a memory unit that has not been read by the reading unit. 4. The image forming apparatus according to claim 3, wherein access to the storage unit by a reading unit and a writing unit is performed in parallel. 5. The storage device according to claim 4, wherein the storage unit has n + p memory units when a maximum value of a that can be taken by the recording control unit is p in a range of a <n. The image forming apparatus as described in the above. 6. The reading means and the writing means combine a first bit string capable of expressing h / n addresses and a second bit string capable of expressing m addresses to obtain an access address to a memory unit. 2. The method according to claim 1, wherein
An image forming apparatus according to claim 1. 7. When executing recording in the n / a pass mode, the writing means writes dummy data indicating no recording into na memory blocks at the time of writing head data of an image. 4. The image forming apparatus according to claim 3, wherein writing of data starting from the head data is performed from a memory block located in the access order of the image forming apparatus. 8. The writing means according to claim 3, wherein after writing of all image data is completed, dummy data indicating no recording is written in at least n / a-1 memory blocks. An image forming apparatus according to claim 1. 9. The image forming apparatus according to claim 1, wherein the recording head is an inkjet recording head that performs recording by discharging ink. 10. The recording head according to claim 1, wherein the recording head ejects ink using thermal energy, and is an inkjet recording head including a thermal energy converter for generating thermal energy to be applied to the ink. The image forming apparatus according to claim 9, wherein: 11. The recording head according to claim 1, wherein a state change is caused in the ink by thermal energy applied by the thermal energy converter, and the ink is ejected from an ejection port based on the state change. The image forming apparatus according to claim 10. 12. A recording head comprising a pixel composed of one or a plurality of dots and capable of recording an image of m pixels in a scanning direction and h pixels in a sub-scanning direction orthogonal to the scanning direction in one recording scan. A storage unit including at least n memory units having a data capacity corresponding to image data of at least m × h / n pixels, comprising: A reading unit for sequentially accessing the units and reading data by h / n pixels at a time from each memory unit to obtain data in the sub-scanning direction of h pixels, and repeating this m times to provide data necessary for print scanning to the printing unit; A control step of repeating the reading step while changing an access order to the memory unit in the storage step for each recording scan; A writing step of writing new image data in units of memory units in accordance with the access order. 13. Each time a recording scan is performed, h / n is set in the sub-scanning direction.
A printing control step of controlling the printing unit to perform printing in an n-pass mode in which printing is performed while shifting the printing position by the number of pixels to complete printing by n printing scans of the print head. 13. The control method for an image forming apparatus according to claim 12, wherein: 14. The print control step, wherein the print scan is performed n / a times by shifting the print position by h / (n / a) pixels in the sub-scanning direction for each print scan. N / a that completes printing by printing scanning
14. The method according to claim 13, wherein printing in a pass mode is executable, and the control step changes the access order in units of a memory units. 15. The storage unit includes more than n memory units, and writes new image data in the writing step to a memory unit that has not been read in the reading step. 15. The method according to claim 14, wherein access to the storage unit in a reading step and a writing step is performed in parallel. 16. The storage device according to claim 15, wherein in a range of a <n, when a maximum value of a that can be taken by the recording control step is p, the storage means has n + p memory units. The control method of the image forming apparatus described in the above. 17. The method according to claim 17, wherein the reading step and the writing step include h / n
13. The method according to claim 12, wherein a first bit string capable of expressing a plurality of addresses and a second bit string capable of expressing m addresses are combined to form an access address to a memory unit. . 18. The writing step, in the case of executing recording in the n / a pass mode, writes dummy data indicating non-recording into na memory blocks when writing head data of an image. 15. The method according to claim 14, wherein writing of data starting from the head data is performed from a memory block located in the access order of (1). 19. The writing step, wherein after writing of all image data is completed, dummy data indicating no recording is written into at least n / a-1 memory blocks. 3. The method for controlling an image forming apparatus according to claim 1. 20. A recording head which forms a pixel by one or a plurality of dots and is capable of recording an image of m pixels in a scanning direction and h pixels in a sub-scanning direction orthogonal to the scanning direction in one recording scan. A memory control method in an image forming apparatus, comprising: a recording unit having at least n memory units having a data capacity corresponding to image data of at least m × h / n pixels. A reading step of sequentially accessing the memory units and reading data by h / n pixels from each memory unit to obtain data in the sub-scanning direction of h pixels, and repeating this m times to read data necessary for print scanning; A control step of repeating the reading step while changing an access order to the memory unit in the storage step every time, and an access controlled by the control step. Depending on the scan order, a memory control method characterized by comprising a write step of writing new image data memory unit as a unit. 21. A recording head which forms a pixel by one or a plurality of dots and is capable of recording an image of m pixels in a scanning direction and h pixels in a sub-scanning direction orthogonal to the scanning direction in one recording scan. A control program for causing a computer to control an image forming apparatus comprising: a recording unit having at least n recording units having at least n memory units having a data capacity corresponding to image data of at least m × h / n pixels. The control program sequentially accesses n memory units, reads out data from each memory unit h / n pixels at a time, and sets the data as sub-scanning direction data for h pixels, and repeats this for m times. A code of a reading step for providing data necessary for a printing scan to the printing means, and an access order to a memory unit in the storage step for each printing scan And a code for a writing step of writing new image data in units of memory units according to an access order controlled by the control step. Storage medium.