JPH09201986A - Image recording device - Google Patents

Abstract

(57) Abstract: By distributing data processing for a plurality of print heads, a printing speed is increased and a circuit configuration is simplified. SOLUTION: Different inks are ejected based on print data stored in a print buffer.
A plurality of (4) print heads arranged in the main scanning direction,
After temporarily storing the print data in the print buffer,
A 2-bit shift register unit 54 and a 2-bit shared shift register unit 56 that sequentially supply the print data to each print head in dot units, and a plurality of print heads are divided into two groups, and the print heads of the divisions are supported. And buffer control means for transferring the print data from the print buffer to the register units 54 and 56 while shifting the timing. 2-bit shared shift register unit 5
6 is shared by the 2-bit shift register unit 54, and the two registers 54a and 54b or 54 of the 2-bit shift register unit 54 are switched by switching the selector circuit 55a.
The print data is sequentially shifted in dot units to either c or 54d.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus for printing in band units by main scanning a print head.

[0002]

2. Description of the Related Art An information recording apparatus such as a personal computer is usually connected to an image recording apparatus capable of recording data such as characters and figures as visual information and recording such data on a sheet. (See Figure 4). This recording device has an impact method, a thermal method,
Although various printing methods such as an inkjet method are adopted, a normal recording apparatus performs main scanning with a print head provided with a plurality of recording elements of these methods (for example, 64 channels) and prints one band on a sheet. After this, the printing process of sub-scanning the paper by one band width is repeated to print on the entire surface of the paper.

That is, the conventional recording apparatus, as shown in FIG. 11, does not show a print buffer 61 capable of storing print data for at least one band and a recording operation of each recording element of the print head. A print head drive unit and a print control unit 64 including a DMA controller 62 for outputting print data to the print head drive unit in dot units so as to correspond to channels of respective recording elements, a 4-bit shift register unit 63, and the like are provided. doing.

The operation for printing will now be described while paying attention to the 0-channel register 63a and the 1-channel register 63b of the 4-bit shift register section 63, as shown in FIG. Minute print data (○ 0-3, ● 0-3)
After being transferred to the 4-bit shift register section 63 by the DMA controller 62 (S1), the print data (○
0 to 3, 0 to 3) are output from the first bit to each recording element of the print head 65 in 1-bit units at the input timing of the print clock to perform printing (S2 to S4). After this, when the final print data (○ 3, ● 3) is output from the 4-bit shift register section 63, the next 4-bit print data (○ 4-7, ● 4-7) is printed.
Transfer from 1 to 4 bit shift register 63 (S
5) The subsequent printing is performed at the print clock input timing (S6 to S8). Then, by repeating such transfer and printing of print data, printing for one band is performed.

[0005]

However, as in the prior art described above, for example, in S5 and S9, after the final print data is output from the 4-bit shift register unit 63, the next print clock is input. Within the period,
Print data of 4 bits from print buffer 61 to 4
In the configuration of transferring 64 channels to the bit shift register unit 63, it is difficult to shorten the transfer time required for one channel due to restrictions such as the reading speed of the print buffer 61, so the following transfer is completed until transfer of all channels is completed. There is a problem that the printing speed must be reduced so that the printing clock is not input. In addition, since the shift registers for all channels have a 4-bit configuration,
There is also a problem that the circuit configuration is complicated. And
These problems become more serious when the color printing or the like is performed by a plurality of print heads because the number of channels further increases.

Therefore, the present invention intends to provide an image recording apparatus capable of increasing the printing speed by distributing the data processing for a plurality of print heads and simplifying the circuit configuration. Is.

[0007]

In order to solve the above-mentioned problems, the invention of claim 1 is based on a print buffer for storing print data received from an information processing device and a print data stored in the print buffer. After printing the print data in the print buffer and a plurality of print heads arranged in the main scanning direction,
Storage means for sequentially supplying the print data to the print heads in dot units, and buffer control means for transferring print data corresponding to the print heads from the print buffer to the storage means while shifting the timing. The storage means is commonly used by the first shift register unit and the first shift register unit that sequentially supplies the print data to the print heads in dot units, and the print data is dot-printed in the first shift register unit. It is characterized in that it has a second shift register portion which is sequentially supplied in units. As a result, the print data corresponding to the print heads is transferred from the print buffer to the storage means while shifting the timing, so that the transfer can be completed in a shorter time than when the print data of all print heads are transferred at the same time. As a result, the printing speed can be increased. Furthermore, by sharing the second shift register unit with the first shift register unit,
Since the number of shift registers in the shift register section can be reduced, the circuit configuration can be simplified.

According to a second aspect of the present invention, in the image recording apparatus according to the first aspect, the buffer control means divides the plurality of print heads into at least two groups, and each print head belonging to each division. The print data corresponding to each print head is transferred from the print buffer to the storage means at different timings. As a result, print data corresponding to a plurality of print heads belonging to the same section can be simultaneously transferred at one transfer timing, which is particularly suitable for a head having a relatively small number of print elements, and timing Can be easily switched.

According to a third aspect of the present invention, in the image recording apparatus according to the first aspect, the buffer control means prints the print data corresponding to each print head at different timings for each of the plurality of print heads. It is characterized in that the data is transferred from the buffer to the storage means. As a result, print data can be transferred at different timings for each of a plurality of print heads, which is particularly suitable for a head having a relatively large number of print elements, and printing can be performed at a higher speed. .

The invention of claim 4 is the image recording apparatus according to any one of claims 1 to 3, characterized in that the print heads perform printing in different colors. As a result, color printing of a plurality of colors can be performed at high speed with a simple circuit configuration.

According to a fifth aspect of the present invention, in the image recording apparatus according to any one of the first to third aspects, the print heads perform single-color printing at different positions on the printing paper. Is characterized by. As a result, printing of a single color such as black and white printing can be performed at extremely high speed with a simple circuit configuration.

The invention according to claim 6 is the image recording apparatus according to any one of claims 1 to 5, characterized in that the print heads are arranged at intervals of an integral multiple of a print pitch. . As a result, the transfer control of the print data corresponding to each of the plurality of print heads can be easily performed according to the print pitch.

The invention according to claim 7 is the image recording apparatus according to any one of claims 1 to 6, characterized in that the print head is an ink jet head for printing by ejecting ink. . As a result, inkjet printing can be performed at high speed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. The image recording apparatus according to the present embodiment is connected to an information processing apparatus 1 such as a personal computer as shown in FIG. The information processing device 1 is used for inputting and instructing data, a processing device main body 2 having a built-in auxiliary storage device such as a magnetic disk device and a central processing unit, a CRT (cathode-ray tube) 3 for displaying data and the like on a screen. It has a keyboard 4 and a mouse 5 and is connected to an ink jet printer 7 which is an image recording device via a printer cable 6 of Centronics specification, for example.

As shown in FIG. 5, the processing apparatus main body 2 includes, for example, a window system 8 as an operating system (OS). The window system 8 includes an application 9 such as a document creation program, a font driver 10 for managing fonts, a CRT driver 11 for managing the CRT 3, a keyboard driver 12 for managing the keyboard 4, and a mouse driver 13 for managing the mouse 5. , One or a plurality of applications 9 can be simultaneously executed in cooperation with various functional groups such as the printer driver 14 that manages the printer 7.

The printer driver 14 is capable of forming dot image data in the color print mode and the monochrome print mode. For example, in the color print mode, halftone image data to be printed is generated. Based on the binarization processing such as the dither method or the error diffusion method, dot image data of four colors of yellow color (Y), magenta color (M), cyan color (C), and black color (K) is formed. The data is output from the interface (I / F) unit 15 as 8-bit print data while raster-scanning these data in the horizontal direction.

The print data output in the raster scan format as described above is input to the I / F (interface) unit 16 of the printer 7. The printer 7 includes a printer controller 17, print buffers 18a to 18d for storing print data for yellow (Y), magenta (M), cyan (C), and black (K), and a print head. It has a drive unit 19 and a CR motor drive unit 20. CR motor drive unit 20
Is connected to the CR motor 22 and
It is designed to rotate forward and backward. on the other hand,
The print head drive unit 19 is connected to the print heads 21a to 21d for yellow color (Y), magenta color (M), cyan color (C), and black color (K). In each of these print heads 21a to 21d, nozzles (printing elements) (not shown) that eject ink by displacement of the piezoelectric elements are arranged in the sub-scanning direction for, for example, 64 channels, and the piezoelectric elements of these nozzles are A drive voltage from the print head drive unit 19 is applied so as to displace the piezoelectric element.

The print head drive unit 19 will be described in detail. As shown in FIG.
Buffer units 33a to 33d including buffer circuits provided corresponding to the nozzles of the print heads 21a to 21d.
And gate units 32a to 3 formed of 2-input AND circuits connected to the respective buffer circuits of the buffer units 33a to 33d.
2d and a serial-parallel conversion circuit 31 connected to one input side of each AND circuit of the gate units 32a to 32d.
And The serial-parallel conversion circuit 31
From the print buffers 18a to 18d shown in FIG.
The dot-unit print data serially output via the controller 17 is taken in at the input timing of the transfer clock and is output in parallel. Further, the gate units 32a to 32d are configured to output the print data output in parallel to the buffer units 33a to 33d, respectively, when the high-level print clock is input, and the buffer units 33a to 33d are input. Drive voltage (Y, M,
C and K) are respectively output to the print heads 21a to 21d.

In this way, the print heads 21a to 21d to which the drive voltage is supplied from the print head drive unit 19 are arranged in the main scanning direction X as shown in FIG. The arrangement interval between the adjacent print heads 21a to 21d is as shown in FIG.
, The print pitch is an integer multiple (print head 21a
・ 4 dots between 21b, 6 dots between print heads 21b and 21c, and 4 dots between print heads 21c and 21d
The dot image data (print data) is stored in the print buffers 18a to 18d at equal intervals of 4 bits, as will be described in detail later. It is designed to let you.

Further, these print heads 21a to 21d
As shown in FIG. 7, is fixed to the carriage 23 such that the ink ejection direction is at a predetermined angle with respect to the printing paper 25. A guide shaft 24 horizontally provided in the main scanning direction is movably inserted into the carriage 23, and a scanning belt 26 driven by the CR motor 22 is connected to the carriage 23. The motor 22 moves the carriage 23 forward and backward along the guide shaft 24 in the main scanning direction to maintain a constant distance between the print head 21 and the paper 25, and the print head 21.
The main scanning is performed.

On the lower surface of the carriage 23, an encoder element 2 including a non-contact type sensor such as an optical type or a magnetic type is provided.
7 are provided. In the detection direction of the encoder element 27, a timing slit 28 having a large number of slit portions 28a at equal intervals is provided in parallel with the guide shaft 24.
At the same time, when it moves in the main scanning direction, the slit portion 28a of the timing slit 28 is detected and output as an encoder signal.

The above encoder signal is input to the printer controller 17, as shown in FIG. The printer controller 17 has a print timing generation section 34, a buffer control section 35, a CPU section 38, and an I / I so as to function as the buffer control means of the present invention.
It has an F control unit 42 and a print control unit 43. The print timing generator 34, the buffer controller 35, the I / F controller 42, and the print controller 43 are integrally formed by a hard logic circuit such as an ASIC (Application Specific Integrated Circuit). The ASIC section 39 is configured.

The print timing generating section 34 constituting the ASIC section 39 forms a print timing signal as a print clock based on the encoder signal described above, and the print timing signal is supplied to the buffer control section 35 and the print control section. It is designed to output to 43. The buffer control unit 35 includes a DMA controller, an address generator, and the like, and stores the print data input via the I / F unit 16 in the print buffers 18a to 18d and the print buffers 18a to 18d. A read process of reading the selected print data and outputting it to the print control unit 43 is executed.

That is, the write processing and the read processing will be specifically described. Each of the print buffers 18a to 18a.
As shown in FIGS. 9A and 9B, d has a matrix shape of, for example, 6 in a horizontal direction (raster direction) corresponding to the main scanning direction X and a vertical direction corresponding to the sub scanning direction.
A data table for four rasters is formed. This data table is divided into 8-bit data areas, which are the transmission units of print data, and when write processing is performed, print data is sequentially output in the same raster scan format as that output from the information processing apparatus 1. It is designed to be stored in each data area. On the other hand, when the reading process is performed, the print data in the vertical direction, which is the sub-scanning direction, is sequentially read in the horizontal direction from the left end in the drawing.

The print data read by the above-mentioned reading process is output to the print control unit 43 as shown in FIG. Then, the print controller 43
After the print data in the print buffer 18 is temporarily stored, the print data is dot by dot in the print head drive unit 1.
9 are sequentially transmitted.

More specifically, as shown in FIG. 10, the print control unit 43 includes a parallel-serial conversion unit 51 for serially transferring print data in dot units to the print head drive unit 19 at the input timing of the transfer clock, and a parallel-serial conversion unit 51. For black (K), magenta (M), cyan (C), and yellow (Y) so that the print data of all channels (64 channels x 4 colors) is output in dot units to the serial conversion unit 51. 2 bit shift register unit 54 having (2 × 4) 2 bit shift registers in this order
And

Further, the print control section 43 controls the selector circuits 55a ... 57a ...
2) a first selector unit 55 and a second selector unit 57 which are provided, a 2-bit shared shift register unit 56 which has (64 × 2) 2-bit shift registers, a data selector 53, a selector circuit 55a ... .K / M, C / Y head switching circuit 58 for switching the connection direction of 57a ...
And

The output terminal of the selector circuit 55a provided in the first selector section 55 is connected to the shift registers of adjacent channels in the 2-bit shift register section 54 (for example, K0 channel register 54a and M0 channel register 54b). ing. On the other hand, the shift register of the 2-bit shared shift register unit 56 (for example, the K0 / M0 channel shared register 56a) is connected to the input terminal of the selector circuit 55a. As a result, the first selector unit 55 switches the output direction of the selector circuit 55a so that the shift register (K0 / M0 channel shared register 56a) of the 2-bit shared shift register unit 56 is changed to the 2-bit shift register unit 5.
4 adjacent channel shift registers (eg K0
The channel register 54a and the M0 channel register 54b) are commonly used.

On the other hand, the output terminal of the selector circuit 57a provided in the second selector section 57 is connected to the shift registers of adjacent channels in the 2-bit shift register section 54 (for example, the K0 channel register 54a and the M0 channel register 54b). ing. As a result, the second selector unit 57 causes the lower 2 bits of the print data in units of 4 bits to shift from the data selector 53 to the shift register of the 2-bit shared shift register unit 56 (for example, K0 /
At the same time as it is directly stored in the M0 channel shared register 56a), the upper 2 bits of the print data are switched to the output direction of the selector circuit 57a so that one shift register (for example, the K0 channel register 54a or the M0 channel register 54a or M0). Channel register 54
It is designed to be stored in b).

The operation of the image recording apparatus having the above structure will be described. First, as shown in FIG. 4, when instruction data is input by the keyboard 4 or mouse 5 to start printing, the window system 8 in FIG. 5 operates the printer driver 14. When the instruction content is the color print mode, R is printed based on the color print data (halftone RGB image signal) to be printed.
The color signal is converted from the GB image signal into the CMY signal, and the black amount (K value) is determined based on the CMY signal. After this, CMY based on the black ink amount (K value)
The signal is corrected (referred to as under color removal (UCR)), and the dot image data of each color is created by the binarization process using the dither method, the error diffusion method, or the like.

Next, by transmitting a color print mode setting command to the printer 7, a data area for the print buffers 18a to 18d is formed so that the printer controller 17 can perform color printing. become. After that, the dot image data of yellow color (Y), magenta color (M), cyan color (C), and black color (K) is transmitted as print data and stored in the print buffers 18a to 18d, respectively. .

When the print data for one band is stored in the print buffers 18a to 18d, as shown in FIGS.
As shown in, the CR motor 22 is rotationally driven in the positive direction, and the forward movement of the print heads 21a to 21d in the main scanning direction X is started. After this, the print heads 21a-2
When 1d reaches the print start position when moving to the right, the buffer control unit 3 instructed to perform the reading process by the CPU unit 38.
5, each of the print buffers 18a ...
The print data of yellow color (Y), magenta color (M), cyan color (C), and black color (K) are read out from 18d by the following procedure and transferred to the print control unit 43.

That is, as shown in FIGS. 1 and 2, the operation of the read processing is performed by K0 of the 2-bit shift register unit 54.
~ Y0 channel registers 54a to 54d and the K0 / M0 channel sharing register 56a and the C0 / Y0 channel sharing register 56b of the 2-bit shared shift register unit 56 will be described. First, a predetermined print clock, for example, 1 pulse. M at the eye input timing
4-bit print data (M0 to M3, Y0 to Y3) corresponding to channels 0 and Y0 is print buffer 1 for magenta (M) and yellow (Y).
The print data (M0 · M1, Y0 · Y1) of the upper 2 bits read out from 8b · 18a is stored in the 2-bit shift register unit 54.
Is transferred to the M0 channel register 54b and the Y0 channel register 54d, and at the same time, the lower 2 bits of the print data (M2.M3, Y2.Y3) are transferred to the K0 / M0 channel sharing register 5 of the 2-bit shared shift register unit 56.
6a and the C0 / Y0 channel shared register 56b, and selector circuits 55a and 57a in the first selector section 55 and the second selector section 57 of FIG.
Output direction of M0 channel register 54b and Y0
It is switched to the channel register 54d (S1).

At this time, the 2-bit shift register section 54
Outputs the data stored in the head register (the rightmost register in FIG. 1) of each channel to the parallel-serial conversion unit 51. Therefore, the K0 to Y0 channel registers 54a to 54d are connected to the print head drive unit 19 via the parallel / serial conversion unit 51 until the next second pulse of the print clock is input (between S1 and S2). The data in the top register will be transferred, but M0
Only 2-bit print data (M0, M1, Y0.
Since Y1) is stored, the print data (M0, Y0) of the first bit stored in the head register among these print data is transferred in 1-bit units.

When the second pulse of the print clock is input, the 2-bit shared shift register section 56 and the 2-bit shift register section 54 are arranged in the K0 / M0 channel shared register 56a and the M0 channel register 54b by the selector circuit 55a. Are connected and the selector circuit 55a connects the C0 / Y0 channel shared register 56b and the Y0 channel register 54d, so that the shared registers 56a.
The print data (M2 · M3, Y2 · Y3) of 6b is transferred (shifted) to the M0 channel register 54b and the Y0 channel register 54d in 1-bit units, and
The first print data (M0, Y0) is print head 21b ・ 2
It is printed by 1a (S2).

Next, when the print pulse of the third pulse is input, the print data (M1, Y1) of the second bit transferred to the print head drive unit 19 immediately before that is printed and K0 4-bit print data (K0 to K3, C0 to C3) corresponding to channels C0 and C0 is read from the print buffers 18d and 18c, and the upper 2 bits of print data (K0 to K1, C0 to C1) is 2 The transfer data is transferred to the K0 channel register 54a and the C0 channel register 54c of the bit shift register unit 54, and the lower 2 bits of print data (K2 · K3, C2 · C3) are shared by the K0 / M0 channel of the 2-bit shared shift register unit 56. It is transferred to the register 56a and the C0 / Y0 channel shared register 56b, respectively. Further, the print data stored in the K0 / M0 channel shared register 56a and the M0 channel register 54b, and the C0 / Y0 channel shared register 56b and the Y0 channel register 54d which are connected until just before the input of the print clock,
After being shifted in 1-bit units, the first of FIG.
The output directions of the selector circuits 55a and 57a in the selector unit 55 and the second selector unit 57 are switched to the K0 channel register 54a and the C0 channel register 54c, respectively (S3).

After that, when the next fourth pulse of the print clock is input, the print data (K0, C0, M2, M2, K0, M0, M2, etc.) transferred from the K0 to Y0 channel registers 54a to 54d to the print data driving unit 19 immediately before that is input. Y2) will be printed (S4). Then, such adjacent channel registers 54a to 54d and the channel sharing register 5
Inputting the print clock from each of the channel registers 54a to 54d is repeated from the print data drive unit 1 while the storage of the print data in units of 4 bits for each 2 bits for 6a and 56b is alternately repeated for every 2 pulses of the print clock.
9 by transferring the print data (S5 to S1
0) Color printing for one band will be performed.

As described above, the image recording apparatus according to the present embodiment has the M0 channel registers 54b and Y0.
Storing print data in the magenta color (M) and yellow (Y) channel registers such as the channel register 54d and the K0 channel registers 54a and C0
Storage of print data in the channel registers for the black (K) and cyan colors (C) of the channel register 54c and the like is alternately repeated every two pulses of the print clock. That is, the print heads 21a to 21
d is divided into two groups, and the print data corresponding to the print heads 21a and 21b of one group and the print data corresponding to the print heads 21c and 21d of the other group are different in timing, that is, the print clock The 2-bit shift register section 54 and the 2-bit shared shift register section 56 are alternately shifted by shifting the timing every two pulses.
To be forwarded to. Therefore, in one cycle of the print clock, the print data is read from the print buffers 18a to 18d and the 2-bit shift register unit 54
The number of channels stored in etc. is half of the total number of channels. As a result, the print data can be stored in a shorter time than in the case where the print data is stored in the shift registers of all channels. Therefore, it is possible to shorten the cycle of the print clock and increase the printing speed of the image recording apparatus. It is possible.

Further, in the present embodiment, (64
× 4) 2-bit shift register section 54 composed of 2 2-bit shift registers and 2-bit shared shift register section 56 composed of (64 × 2) 2-bit shift registers
Since a 4-bit shift register for 64 channels × 4 colors is configured by and, the circuit configuration can be simplified as compared with the case where all channels are configured by 4-bit shift registers. That is, since the shift register requires an extremely large number of gate components as compared with the selector or the like, when these are configured by ASIC, for example, a gate array or the like, they can be manufactured relatively inexpensively.

The print head 21 according to the present embodiment.
The arrangement intervals of a to 21d are the same as the print heads 21a and 21d.
The distance between b is 4 dots, the distance between print heads 21b and 21c is 6 dots, and the distance between print heads 21c and 21d is 4 dots. Therefore, FIG.
As is clear from the above, the print data (M4) of the fifth bit of the magenta color (M) is printed at the position where the print data (Y0) of the first bit of the yellow color (Y) is printed. At the same time, the print data (C0) of the fifth bit of the cyan color (C) is printed at the position where the print data (M0) of the first bit of the magenta color (M) is printed. C) 1st bit print data (C
The print data (K0) of the fifth bit of black (K) is printed at the position where 0) is printed. That is, if the dot-matrix image data is stored as it is in the print buffers 18a to 18d for the respective colors, a 4-bit shift will occur between the respective colors.

Therefore, in order to eliminate such a shift, it is necessary to store dot image data (print data) in which the shifts of 4 bits are made between the print buffers 18a to 18d for the respective colors. . When such a correction process is performed on the information processing apparatus 1 side, for example, the dot image data may be created in consideration of a 4-bit shift when the dot image data is created by the printer driver 14. Alternatively, at the stage of transferring the dot image data to the printer 7, the dot image data may be corrected in consideration of the shift of 4 bits. Further, when the correction is performed on the printer 7 side, the dot image data shifted by 4 bits may be stored at the stage of storing the dot image data received from the information processing device 1 in the print buffers 18a to 18d of the respective colors. good.

Further, the print buffers 18a to 18d are provided.
The dot image data (print data) may be read out from the dot image data (print data) and stored in the 2-bit shift register unit 54 and the 2-bit shared shift register unit 56 by shifting the dot image data by 4 bits. The dot image data (print data) considering the 4-bit shift is converted into 2-bit shift register section 54.
And the 2-bit shared shift register unit 56 may be stored in units of 4 bits.

In the case of performing the correction processing as described above, in the present embodiment, since it is sufficient to eliminate the deviation of equal intervals of 4 bits between the respective colors, the correction processing is extremely easy. For example, as shown as a modification in FIG. 3, the print head 21a is not limited to the above.
The arrangement intervals of ˜21d may be set to be equidistant for 4 dots.

In this case, as is apparent from FIG. 3, the print data of the fifth bit of magenta color (M) is printed at the position where the print data (Y0) of the first bit of yellow color (Y) is printed. (M4) is printed, and the print data (C2) of the third bit of cyan color (C) is printed at the position where the print data (M0) of the first bit of magenta color (M) is printed. Further, the print data (K4) of the fifth bit of black (K) is printed at the position where the print data (C0) of the first bit of cyan (C) is printed. That is, assuming that the dot-matrix image data is stored in the print buffers 18a to 18d for each color as they are, a shift of 4 bits or 2 bits will occur between the colors. However, such a shift can be corrected by performing the above-described correction process, and for example, the print buffers 18a to 18d of the respective colors can be obtained.
Can be solved by storing dot image data (print data) which is shifted by 4 bits or 2 bits between the respective colors.

By the way, in the above embodiment, the four print heads 21a to 21d are divided into two groups, and the print heads 21a and 21b for yellow (Y) and magenta (M) which belong to one of the groups. And the print data corresponding to the cyan (C) and black (K) print heads 21c and 21d belonging to the other group are alternately arranged with a timing shift for every two pulses of the print clock. Although the transfer is performed to the 2-bit shift register unit 54 and the 2-bit shared shift register unit 56, the present invention is not limited to this, and for example, the transfer may be performed at different timings for each print head 21a to 21d. good.

That is, in the above-described embodiment shown in FIG. 1, at the input timing of the print pulse of the first pulse (S1), the print buffers 18a to 18d for the magenta color (M) and the yellow color (Y) respectively output 4 pulses. The print data for bits (M0 to M3, Y0 to Y3) is read out and stored in the channel sharing registers 56a and 56b and the channel registers 54b and 54d, 2 bits each, and the input timing of the print pulse of the third pulse ( S
In 3), print data (K0 to K3, C0 to C3) of 4 bits is read from the print buffers 18d and 18c for black (K) and cyan (C) respectively, and the channel shared registers 56a and 56b and the channels are read. Register 54a ・ 5
Although 2 bits are stored in each of 4c and 4c, this may be changed as follows.

First, at the input timing (S1) of the first pulse of the print clock, the 4-bit print data (Y0 to Y3) is read from the yellow (Y) print buffer 18a, and the channel shared register 56b is read. Stores 2 bits each in the channel register 54d and
Input timing of the second pulse print clock (S2)
Then, the print data (M0 to M3) for 4 bits is read from the print buffer 18b for magenta color (M), and the channel sharing register 56a and the channel register 54b are read.
Store 2 bits each in and. Next, at the input timing (S3) of the print pulse of the third pulse, the 4-bit print data (C0 to C3) is read from the cyan (C) print buffer 18c, and the channel sharing register 56 is read.
b and the channel register 54c, 2 bits each are stored, and at the input timing (S4) of the print pulse of the fourth pulse, the print buffer 18d for black (K) is output.
Read the 4-bit print data (K0 to K3) from
Channel shared register 56a and channel register 5
Two bits are stored in each of 4a and 4a.

After that, at the input timing (S5) of the fifth pulse of the print clock, 4-bit print data (Y4 to Y7) from the yellow (Y) print buffer 18a.
Is read out and stored in the channel sharing register 56b and the channel register 54d in units of 2 bits, in order of yellow color (Y), magenta color (M), cyan color (C), and black color (K). The read operation of print data in units of 4 bits is repeated.

According to such an embodiment, the print buffers 18a to 18d in one cycle of the print clock.
The number of channels for reading the print data from the printer and storing it in the 2-bit shift register unit 54, etc.
This is one-third, and the storage of print data can be completed in a shorter time than in the case of the above-described embodiment, and higher speed printing is possible. Moreover, since the first half 2-bit shift register can be shared, the circuit configuration can be simplified. Even in such an embodiment, the arrangement interval of the print heads 21a to 21d is not limited, and it is needless to say that the print misregistration can be eliminated by appropriately performing the correction process described above. However, for example, the print heads 21a-2
When the arrangement interval of 1d is set to be equidistant for 5 dots, it suffices to eliminate the deviation of equidistant intervals of 4 bits for each color, so that the correction process is easy.

Although the present invention is designed to perform color printing by ejecting inks of different colors from a plurality of print heads, for example, printing with a single color ink such as monochrome printing. Even in an image recording apparatus that performs the above, it is applied to a recording apparatus in which a plurality of print heads in which the array positions of the nozzles are displaced in the sub-scanning direction perform printing of several bands at one time in one main scan. It is possible. Further, the present invention is not limited to the ink jet type printer, but can be applied to, for example, a wire dot type printer equipped with a plurality of print heads.

[0051]

According to the first aspect of the present invention, a print buffer for storing print data received from an information processing apparatus and an array in the main scanning direction for printing based on the print data stored in the print buffer are arranged. Storage means for temporarily storing the print data of the plurality of print heads and the print data in the print buffer, and sequentially supplying the print data to the print heads in dot units; and print data corresponding to the print heads. And a buffer control means for transferring the print data from the print buffer to the storage means while shifting the timing, the storage means sequentially supplying the print data in dot units to the print heads, and A second system which is shared by the first shift register section and which sequentially supplies the print data in dot units to the first shift register section. A Configurations of and a Torejisuta portion.

As a result, the print data corresponding to the print heads is transferred from the print buffer to the storage means while shifting the timing, so that the transfer is completed in a shorter time than when the print data of all the print heads are transferred at the same time. As a result, the printing speed can be increased. Furthermore, the second shift register unit is connected to the first
Since the number of shift registers in the second shift register unit can be reduced by sharing the shift register unit with the shift register unit, the circuit configuration can be simplified.

According to a second aspect of the present invention, in the image recording apparatus according to the first aspect, the buffer control means divides the plurality of print heads into at least two groups, and each print head belonging to each division. The print data corresponding to each print head is transferred from the print buffer to the storage means at different timings. This allows
The print data corresponding to a plurality of print heads belonging to the same section can be simultaneously transferred at one transfer timing. For example, it is particularly suitable for a head having a relatively small number of print elements, and the timing can be switched. It will be easy.

According to a third aspect of the present invention, in the image recording apparatus according to the first aspect, the buffer control means prints the print data corresponding to each print head at different timings for each of the plurality of print heads. The configuration is such that the data is transferred from the buffer to the storage means. As a result, print data can be transferred at different timings for each of a plurality of print heads, which is particularly suitable for a head having a relatively large number of print elements, and printing can be performed at a higher speed. .

The invention according to claim 4 is the image recording apparatus according to any one of claims 1 to 3, wherein the print heads print in different colors. As a result, color printing of a plurality of colors can be performed at high speed with a simple circuit configuration.

The fifth aspect of the present invention is the image recording apparatus according to any one of the first to third aspects, wherein each of the print heads prints a single color at different positions on the print paper. As a result, printing of a single color such as black and white printing can be performed at extremely high speed with a simple circuit configuration.

The invention according to claim 6 is the image recording apparatus according to any one of claims 1 to 5, wherein the print heads are arranged at intervals of an integral multiple of a print pitch. As a result, the transfer control of the print data corresponding to each of the plurality of print heads can be easily performed according to the print pitch.

According to a seventh aspect of the invention, there is provided the image recording apparatus according to any one of the first to sixth aspects, wherein the print head is an ink jet head which prints by ejecting ink. As a result, inkjet printing can be performed at high speed.

[Brief description of drawings]

FIG. 1 illustrates an embodiment of the present invention and is an explanatory diagram illustrating data processing in a print control unit.

FIG. 2 is an explanatory diagram showing a state in which each print head prints.

3 is an explanatory view corresponding to FIG. 2, showing an example in which a print head array interval is changed.

FIG. 4 is a perspective view of an image recording device to which an information processing device is connected.

FIG. 5 is a block diagram of an information processing device and an image recording device.

FIG. 6 is a circuit diagram of a head drive unit.

FIG. 7 is a perspective view of a main part of the image recording apparatus.

FIG. 8 is a block diagram including an ASIC unit.

9A and 9B are explanatory diagrams showing a data area of a print buffer, FIG. 9A is a diagram showing a bit state, and FIG. 9B is a diagram showing a dot state.

FIG. 10 is a block diagram of a print control unit.

FIG. 11 is a block diagram of a conventional print control unit.

FIG. 12 is an explanatory diagram showing data processing in a conventional print control unit.

[Explanation of symbols]

16 I / F unit 17 Printer controller 18a to 18d Print buffer 19 Print head drive unit 20 CR motor drive unit 21a to 21d Print head 22 CR motor 23 Carriage 24 Guide shaft 25 Paper 26 Scan belt 27 Encoder element 28 Timing slit 35 Buffer Control unit 38 CPU unit 43 Print control unit 51 Parallel-to-serial conversion unit 53 Data selector 54 2-bit shift register unit (first shift register unit) 55 First selector unit 56 2-bit shared shift register unit (second shift register unit) 57 Second selector section

Claims (7)

[Claims] 1. A print buffer for storing print data received from an information processing device, and a plurality of print heads arranged in the main scanning direction so as to print based on the print data stored in the print buffer. Storing the print data in the print buffer temporarily, and sequentially storing the print data in dot units to the print heads; and printing the print data corresponding to the print heads while shifting the timing. A buffer control means for transferring the data from the buffer to the storage means, wherein the storage means includes a first shift register section for sequentially supplying the print data in dot units to the print heads, and a first shift register section. A second shift register unit that is commonly used and sequentially supplies the print data to the first shift register unit in dot units. Image recording apparatus characterized by having. 2. The buffer control means divides the plurality of print heads into at least two groups, and print data corresponding to each print head from the print buffer at different timings for each print head belonging to each division. The image recording apparatus according to claim 1, wherein the image recording apparatus transfers the image data to the storage unit. 3. The buffer control means transfers the print data corresponding to each print head from the print buffer to the storage means at different timings for each of the plurality of print heads. Image recording device. 4. The image recording apparatus according to claim 1, wherein the print heads print different colors. 5. The image recording apparatus according to claim 1, wherein each of the print heads prints a single color at different positions on a print sheet. 6. The image recording apparatus according to claim 1, wherein the print heads are arranged at intervals of an integral multiple of a print pitch. 7. The image recording apparatus according to claim 1, wherein the print head is an ink jet head that prints by ejecting ink.