JP2006281457A - Liquid ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid ejector which can perform data transfer to a proper head at a high speed without a scale of hardware enlarged while positional control based on an arrangement position of nozzle arrays at the head is taken into account. <P>SOLUTION: The liquid ejector has a head part equipped with a plurality of the nozzle arrays, a storing means which stores ejection data for each nozzle array, a buffering means for each nozzle array which holds the ejection data before outputting the data to the head part, and a transferring means which transfers the ejection data to the buffering means. Adjustment of the ejection data based on the arrangement position of the nozzle arrays is carried out by a reading position at the buffering means of each nozzle array when the data is outputted to the head part. A transfer order of the ejection data to each buffering means is determined on the basis of an operation mode. The ejection data of each nozzle array is stored in the storing means by an order according to the transfer order. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid ejecting apparatus such as an ink jet printer, and more particularly, to a liquid ejecting apparatus capable of efficiently performing a process of properly transferring ejection data for a plurality of nozzle arrays ejecting liquid to a head.

  In an ink jet printer that is one of liquid ejecting apparatuses, a nozzle array including a plurality of nozzles that eject ink is usually moved relative to a print medium, and is arranged by ink ejected (ejected) from each nozzle. A dot is formed for each pixel. In a color ink jet printer, the nozzle row is provided for each color of ink, and they are installed at a predetermined interval in the movement direction.

  In addition, in the ink jet printer, ejection data (print data) indicating on / off of ejection from each nozzle is created, and in a portion where this data is transferred to the head including the nozzle row, the data is transferred in a predetermined order. For the reason, the created data is buffered once, and then a predetermined amount of data is transferred to the head at a predetermined timing.

  Further, as described above, since the installation positions of the nozzle arrays differ in the movement direction, it is necessary to correct the position of the ejection data for the nozzle arrays in accordance with the installation positions. This was performed before the data buffering described above. In other words, the data transfer unit to the head has only to buffer a predetermined amount of data and output it in a predetermined order without regard to the position correction.

Such a conventional apparatus is described in, for example, Patent Document 1 below.
JP 2000-33738 A

  However, in the above-described position correction between nozzle rows, it is necessary to shift ejection data in bit units. In the conventional apparatus, such processing is performed by a shift operation by software (CPU), and this shift operation in bit units is performed. Has a heavy CPU load, which hinders improvement in printing speed and throughput.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid ejecting apparatus capable of performing data transfer to an appropriate head in consideration of position control based on the arrangement position of nozzle rows in the head without increasing the scale of hardware. Is to provide.

  In order to achieve the above object, one aspect of the present invention includes a plurality of nozzle rows arranged in the main scanning direction, and is relative to the medium in the main scanning direction based on the received ejection data. A head unit that discharges liquid while moving, a storage unit that stores the discharge data for each nozzle column, and each nozzle row that holds the discharge data stored in the storage unit before being output to the head unit In the liquid ejecting apparatus, the head unit based on the arrangement position of the nozzle row in a liquid ejecting apparatus, comprising: a buffering unit provided for each of the units; and a transfer unit that transfers ejection data stored in the storage unit to the buffering unit. The adjustment of the ejection data to be output to the position at the reading position in the buffering means for each nozzle row when outputting from the buffering means to the head unit The transfer order of the ejection data from the storage means to each of the buffering means is determined based on the set operation mode, and the respective orders are determined in accordance with the determined transfer order. The ejection data of the nozzle array is stored in the storage means.

  Furthermore, in the above-described invention, a preferable aspect is that the adjustment of the ejection data output to the head unit according to the read position is the first in the buffering means of each nozzle row for the ejection data for one scan of the head unit. The reading position is determined based on the operation mode.

  Furthermore, in the above invention, a preferred aspect further includes a register that holds the determined transfer order, and the ejection data is transferred from the storage means to the buffering means according to the transfer order held in the register. It is performed.

  Furthermore, in the above invention, a preferred aspect is that when a transfer request to the buffering unit is made in an order different from the determined transfer order, the discharge data from the storage unit to the buffering unit is transferred. The transfer is not performed.

  In the above invention, according to one aspect, each of the buffering units includes two buffers of the same size, and while the ejection data is output from the one buffer to the head unit, The ejection data is transferred from the storage means to the other buffer.

  Further objects and features of the present invention will become apparent from the embodiments of the invention described below.

  Embodiments of the present invention will be described below with reference to the drawings. However, such an embodiment does not limit the technical scope of the present invention. In the drawings, the same or similar elements are denoted by the same reference numerals or reference symbols.

  FIG. 1 is a configuration diagram according to an embodiment of a liquid ejecting apparatus to which the present invention is applied. The printer 1 in FIG. 1 is a liquid ejecting apparatus to which the present invention is applied, and each color that is held before the print data (discharge data) of each color (nozzle array) stored in the memory 10 (storage means) is output to the head 13. Each buffer, and based on the print mode (operation mode), the data read start position in each buffer when data is output from the buffer to the head 13 and the order in which the data is transferred from the memory 10 to each buffer. By deciding and storing the print data of each color in the memory 10 in accordance with the order, an appropriate data transfer is attempted efficiently and efficiently even with the 1-channel DMA method.

  A printer 1 according to the present embodiment is an ink jet printer as an example, and as shown in FIG. 1, an I / F 2, a CPU 3, an image processing unit 4, a memory 10, a local bus 11, a DSP 12, a head 13, and the like. It consists of A print request and print data transmitted from the outside such as a host computer are stored in the memory 10 via the I / F 2. Thereafter, the received compressed print data is subjected to decompression processing, color conversion processing, halftone processing, pass separation processing, and data rearrangement processing by the image processing unit 4, DSP 12, etc. The subsequent data is output to the head 13 in an appropriate order. The head 13 sequentially ejects ink based on the transferred print data and executes printing on the print medium.

  The I / F 2 is a part that controls an interface with the outside of the printer 1 such as a host computer, and the CPU 3 is a part that controls the various image processes. The memory 10 is an external memory provided outside the image processing unit 4 and stores each print data in a predetermined area in a state received from the outside and a state after the processing of each image processing described above. Accordingly, data after halftone processing, data after pass decomposition, data after rearrangement processing, and the like are stored in the memory 10, respectively.

  Next, as shown in FIG. 1, the image processing unit 4 includes a path control unit 5, a decompression unit 6, a path decomposition unit 7, a rearrangement processing unit 8, a head output unit 9, and the like. ASIC. The path control unit 5 is a part that performs transfer control of data input to the printer 1 via the I / F 2, and the decompression unit 6 is a part that performs the decompression process of the compressed print data.

  The pass separation unit 7 is a part that performs a process of dividing the print data after the halftone process for each scan (pass) of the head 13. The head 13 has a nozzle row 131 having a plurality of nozzles 132 for ejecting ink for each color in the sub-scanning direction, and sequentially ejects ink while moving in the main scanning direction. Since one line in the main scanning direction is printed by a plurality of scans (passes), it is necessary to distribute the print data of one raster for each scan (pass), and such pass separation processing is performed.

  Next, the rearrangement processing unit 8 is a part that performs processing for rearranging the print data after the pass decomposition for each unit data.

  The head output unit 9 is a part that reads the print data rearranged by the rearrangement processing unit 8 and outputs the print data to the head 13 in an appropriate order. The print data of each color that stores the read print data therein. A buffer 94 (buffering means) is provided. The printer 1 is characterized by transfer of print data using the print data buffer 94, and the specific contents will be described later.

  Next, the DSP 12 is a processor (Digital Signal Processor) that performs the color conversion process and the halftone process described above, reads predetermined print data stored in the memory 10, executes the process, and processes the processed data. Write back to the memory 10 again.

  As shown in FIG. 1, each processing unit of the image processing unit 4 and the memory 10 are connected by a local bus 11 for performing high-speed data communication with the memory 10 necessary for each processing unit. The local bus 11 is a so-called data bus, and a CPU bus that connects each processing unit in the image processing unit 4 and the CPU 3 is not shown in the image processing unit 4.

  Finally, the head 13 has the nozzle row 131 for each ink color as described above, and sequentially ejects ink according to the print data transferred from the head output unit 9 while moving in the main scanning direction to the print medium. This is the part that performs printing. The nozzle 132 provided in the head 13 is provided with an epizo element (drive device). When a predetermined drive voltage (drive waveform) is applied from a control circuit (not shown), the epizo element Is distorted and ink is ejected.

  FIG. 2 is a diagram illustrating a configuration of a portion that transfers print data, which is a characteristic portion of the printer 1. As shown in FIG. 2, the memory 10 stores print data of each color to be output to the head 13 in a predetermined order. In the printer 1, printing is performed with four color inks of CMYK (cyan, magenta, yellow, and black), and C, Y, M, and K shown in the drawing indicate print data for each color. Each print data is stored in the order corresponding to the print mode as described above, and the order shown in the figure is, for example, the case of the print mode in which printing is performed at a resolution of 720 DPI. The size of the print data for each color is the same size as each print data buffer 94 described later.

  Next, the DMA controller 14 (transfer means) is a part that manages processing for transferring the print data of each color from the memory 10 to each print data buffer 94 when the print data is output from the memory 10 to the head 13. . The printer 1 employs a one-channel DMA system for such data transfer.

  The DMA order setting register 91 shown in FIG. 2 is a register for setting the order in which data is transferred from the memory 10 to the print data buffer 94 for each color, and is suitable for the print mode by the CPU 3 when the print mode is designated. Order is set. In the DMA order setting register 91, as shown in FIG. 2, there are a current color register, a next color register, a third color register, and a fourth color register. In order from the color of data stored in the current color register, This indicates that data transfer is performed to the print data buffer 94. As will be described later, when one data transfer is completed, the color data of each register is changed. FIG. 2 shows an initial state when the 720 DPI print mode is set.

  The DMA order management unit 92 operates in conjunction with the DMA order setting register 91 to arbitrate between an internal transfer request from a buffer management unit 93 described later and an external DMA function (DMA controller 14).

  The buffer management unit 93 is provided for each print data buffer 94, and is a part that manages a read start position from each print data buffer 94 when data is output to the head 13 described above. The buffer management unit 93 grasps that the print data stored in the buffer has been used when the read position (pointer) in the corresponding print data buffer 94 has reached the buffer boundary, and At this time, an internal transfer request for requesting data transfer from the memory 10 is generated.

  The print data buffer 94 is a buffer provided for each color that temporarily holds the print data of the color shown in the figure. The print data stored in the memory 10 is temporarily buffered here. After that, it is output to the head 13. In the printer 1, as described above, a data read start position is set for each print data buffer 94 according to the print mode. Although specifically described later, the above-described position correction based on the arrangement position of the nozzle row 131 of each color is achieved by setting the reading start position for each color.

  The DMA order setting register 91, the DMA order management unit 92, the buffer management unit 93, and the print data buffer 94 shown in FIG. 2 are provided in the head output unit 9 in this embodiment.

  As described above, the printer 1 having the above-described configuration is characterized in the process of transferring the print data from the memory 10 to the print data buffer 94 and outputting the data to the head 13 from there. Specific contents of the processing will be described.

  First, processing when the print mode of the printer 1 is set will be described. The print mode is set when the default mode is automatically set when the printer 1 is activated, or when the print mode is switched by a user operation. When the print mode is set, the CPU 3 first determines the reading start position in the print data buffer 94 for each color described above, and determines it in the buffer management unit 93 described above when outputting the print data to the head 13. Each start position is indicated. This read start position means a position where data is read out from each print data buffer 94 when data is output from the print data buffer 94 to the head 13 at the start of the printing process of one scan of the head 13.

  Next, the CPU 3 determines the data transfer order to the print data buffer 94 of each color suitable for the set print mode, and writes the order in the DMA order setting register 91 described above. That is, the color data is written in each of the current color register, the next color register, the third color register, and the fourth color register described with reference to FIG.

  In addition, since the above-described data transfer order is determined and data transfer is actually performed according to the order, in the printer 1 which is a one-channel DMA system, the data in the memory 10 is arranged in the transfer order. The CPU 3 determines such an arrangement order, and instructs the arrangement order when the print data to be output to the head 13 is generated and stored in the memory 10.

  FIG. 3 is a diagram for explaining the above-described read start position and data transfer order. FIG. 3A is a diagram illustrating an arrangement position of the nozzle row 131 of each color provided in the head 13 of the printer 1. In this example, the nozzle rows 131 are arranged at intervals of 24/360 inches in the order of CMYK. Each nozzle row 131 is provided with a plurality of nozzles 132 in the sub-scanning direction as shown on the right side of the drawing. The head 13 performs printing while moving in the main scanning direction.

  FIG. 3B is a diagram illustrating a read start position (transfer start position) in the 360 DPI print mode. The print data buffer 94 for each color stores print data for each color with a 32-bit width, data in the main scanning direction is arranged in the width direction, and data corresponding to each nozzle 132 in each nozzle row 131 in the vertical direction. Lined up.

  In the case of the arrangement shown in FIG. 3A, if the printing data for one dot of each color is 1 bit, it is necessary to shift the data for 24 bits between the colors, and the left side of FIG. By using the transfer start position shown, the position adjustment based on the arrangement position of the nozzle row 131 can be performed. The position adjustment (shift) in units of 32 bits, that is, in units of one line of the print data buffer 94 is performed by the CPU 3 before being transferred to the head output unit 9.

  When data transfer from such a position to the head 13 is started and data transfer proceeds sequentially, the pointer indicating the data read position of each color sequentially moves to the right, as shown on the right side of FIG. First, the reading position for C reaches the boundary (end in the width direction) of the print data buffer 94. Here, since data transfer from the memory 10 is necessary for the color C, in this case, C is the first in the data transfer order determined by the CPU 3 described above. Thereafter, as the processing proceeds, data transfer from the memory 10 is required in the order of M, Y, and K as is apparent from the figure. In this 360 DPI print mode, the order of CMYK is the DMA order setting described above. It is set in the register 91.

  If the shift in units of bits has already been completed when the print data is stored in the memory 10 as in the conventional apparatus, reading of each color is started from the left end in the print data buffer 94. For each color, data transfer from the memory 10 is required at the same time. Therefore, the setting of the reading start position for each color as described above and the determination of the data transfer order are not performed.

  FIG. 3C shows the 720 DPI print mode. In 720DPI, a 48-bit data shift is required between the nozzle arrays 131, which is the transfer start position shown on the left side of FIG. That is, C and Y are positions shifted by 16 bits from the end of the print data buffer 94, and M and K are the left ends. In this case, as the process proceeds, as shown on the right side of FIG. 3C, data transfer is first required for C and Y, and then data transfer is required for M and K at the same time. Become. Accordingly, the CYMK order is set in the DMA order setting register 91.

  Next, processing when print data is actually transferred from the memory 10 will be described. FIG. 4 is a flowchart illustrating a data transfer process from the memory 10 to the print data buffer 94. When the data output process to the head 13 is being performed, the DMA order management unit 92 receives the internal transfer request from the color buffer management 93 set in the current color register of the DMA order setting register 91. It is checked whether it has occurred (step S1).

  If such an internal transfer request has occurred (Yes in step S1), the DMA order management unit 92 sends a DMA request to the DMA controller 14 to transfer the print data of the color from the memory 10. (DREQ in FIG. 2) is issued (step S2). On the other hand, when the above-described internal transfer request has not occurred (No in step S1), the process waits until there is a corresponding internal transfer request.

  When the DMA request is issued, the DMA controller 14 reads the data from the memory 10 in the order arranged, and transfers the data to the DMA order management unit 92 (step S3). The transferred print data is stored in the corresponding print data buffer 94 from the buffer management unit 93 that issued the internal transfer request (step S4). For example, in the state shown in FIG. 2, if an internal transfer request is generated from the C buffer management unit 93, the color matches the color set in the current color register of the DMA order setting register 91. The DMA request is issued, and the data is stored in the C print data buffer 94.

  As described above, when the data transfer is performed and the corresponding print data buffer 94 is filled with new data, the buffer management unit 93 cancels the generated internal transfer request (step S5). In response, the DMA order management unit 92 outputs a color switching signal to the DMA order setting register 91 (step S6). Note that the DMA order management unit 92 may issue the color switching signal on the assumption that one data transfer is completed by canceling the internal transfer request, or counts the amount of data transferred from the memory 10 to 1 The color switching signal may be issued upon sensing that the data transfer has been completed.

  In response to the color switching signal, the DMA order setting register 91 rotates the value (color data) in each register (step S7). Specifically, the values of the current color register, the next color register, the third color register, and the fourth color register described above are shifted one by one. In the state shown in FIG. 2, as described above, when the data transfer for C is completed and a color switching signal is output, the values of the current color register, the next color register, the third color register, and the fourth color register are as follows. , Are changed (rotated) to Y, M, K, and C, respectively.

  In this way, when one transfer process from the memory 10 is completed, the process returns to step S1 described above and waits for the next internal transfer request. Such processing is repeatedly executed, and print data necessary for printing processing for the scan (pass) is transferred.

  In step S1 described above, if there is an internal transfer request from the buffer management unit 93 of a color different from the color set in the current color register, if a DMA request is issued, the memory 10 performs the same as described above. Since the data is stored in the same order as the DMA order setting register 91, data of a color different from that of the buffer management unit 93 that has issued the internal transfer request is transferred, and proper data transfer cannot be performed. Can not. Accordingly, the processing as described above is performed. As described with reference to FIG. 3, in the 720 DPI print mode, internal transfer requests are generated almost simultaneously in C and Y and M and K, respectively. In some cases, requests are issued in the reverse order.

  In other words, there may be a case where requests are generated in the order of YCMK and CYKM when they are set in the order of CYMK. In such a case, even if the above-described processing is performed and the data transfer is made to wait for the color for which the request has been generated earlier, the DMA transfer from the memory 10 to the print data buffer 94 is performed from the print data buffer 94 to the head. Compared with the data reading to 13, the problem is not caused because it is performed at a sufficiently high speed.

  Although the print data buffer 94 has been described as being provided for each color one by one, a double buffer configuration in which two buffers of the same size are provided for each color may be employed. In such a configuration, two buffers are alternately used, and data is transferred from the memory 10 to the other side while data is being read from one side.

  With such a configuration, even if the order in which data is used for one buffer and an internal transfer request is generated is slightly different from the order in which the DMA order setting register 91 is set in advance, there is a further problem. You will never get In general, in a printer, the print position may be corrected due to a difference in mechanical characteristics between the nozzle rows 131. In such position correction, the print data is shifted by about 1 bit for each nozzle row 131. When such correction is performed, this position correction is performed in a mode in which data transfer is requested for two colors at the same time, such as 720 DPI. As a result, the above-described order of data transfer is changed.

  In consideration of the change in the data transfer order due to the position correction, the data transfer order may be changed for each content of the position correction, but as described above, by using a double buffer, Since there is no problem even if data transfer is waited for the color for which a transfer request has been issued earlier, the fixed data transfer order can be changed depending on the print mode without considering the change of the data transfer order for this position correction. Also good.

  In the DMA order setting register 91 described above, the value stored in the internal register is rotated, but the value stored in each register is fixed, and the value stored in one of the registers is stored. A circuit that selects and outputs to the DMA order management unit 92 may be provided. In such a case, the circuit selects an appropriate color register in accordance with the data transfer order described above, and outputs a current color signal to the DMA order management unit 92 from the value stored therein.

  In the printer 1, four colors of ink are used. However, the four colors are merely examples, and the number of colors may be different. The number of registers in the DMA order setting register 91, the number of buffer managers 93, and the number of print data buffers 94 may be adjusted to the number of colors.

  As described above, in the printer 1 according to the present embodiment, the print data shift based on the nozzle row arrangement position is shifted by the CPU 3 in units of 32 bits and the print data buffer 94 starts reading for each color. This is done properly by determining the position. Further, in order to cope with the difference in the data transfer timing in each print data buffer 94 caused by the determination of the reading start position for each color, an order suitable for the timing is set, and data transfer is performed according to the order. . Further, in order to perform data transfer from the memory 10 to the print data buffer 94 according to the order by the 1-channel DMA method, processing for arranging data in the memory 10 in advance in the order is performed.

  Therefore, the data transfer process to the appropriate head 13 without waiting for the process in the head 13 in consideration of the arrangement position of each nozzle row, without increasing the hardware scale, and the CPU 3 It is possible to execute without increasing the load on the. As a result, the CPU 3 is freed from the conventional shift processing in bit units, and can remove one obstacle to improving the throughput of the printer.

  The protection scope of the present invention is not limited to the above-described embodiment, but covers the invention described in the claims and equivalents thereof.

1 is a configuration diagram according to an embodiment of a liquid ejecting apparatus to which the present invention is applied. FIG. 5 is a diagram illustrating a configuration of a portion that transfers print data. It is a figure for demonstrating a read start position and a data transfer order. 5 is a flowchart illustrating an example of data transfer processing to a print data buffer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer, 2 I / F, 3 CPU, 4 Image processing unit, 5 Pass control part, 6 Decompression part, 7 Pass decomposition | disassembly part, 8 Rearrangement process part, 9 Head output part, 10 Memory (storage means), 11 Local Bus, 12 DSP, 13 heads, 14 DMA controller (transfer means), 91 DMA order setting register, 92 DMA order management section, 93 buffer management section, 94 print data buffer (buffering means), 131 nozzle row, 132 nozzles

Claims (5)

A head unit that includes a plurality of nozzle rows arranged in the main scanning direction and discharges liquid while moving relative to the medium in the main scanning direction based on the received discharge data;
Storage means for storing the discharge data for each nozzle row;
Buffering means provided for each nozzle row, holding the ejection data stored in the storage means before outputting to the head unit;
Transfer means for transferring the ejection data stored in the storage means to the buffering means,
The adjustment of the ejection data to be output to the head unit based on the arrangement position of the nozzle row is performed according to the reading position in the buffering unit for each nozzle row when output from the buffering unit to the head unit. And
Based on the set operation mode, the transfer order of the discharge data from the storage means to the buffering means is determined, and the discharge data of the nozzle rows is determined in the order according to the determined transfer order. Is stored in the storage means. In claim 1,
Adjustment of ejection data to be output to the head unit by the readout position is as follows:
The liquid ejecting apparatus according to claim 1, wherein the first reading position in the buffering unit of each nozzle row with respect to ejection data for one scan of the head unit is determined based on the operation mode. In claim 1 or claim 2,
And a register for holding the determined transfer order.
The liquid ejecting apparatus according to claim 1, wherein ejection data is transferred from the storage unit to the buffering unit in accordance with a transfer order held in the register. In any one of Claim 1 thru | or 3,
When the transfer request to the buffering means is made in an order different from the determined transfer order, the ejection data is not transferred from the storage means to the buffering means. apparatus. In any one of Claims 1 thru | or 4,
Each of the buffering means includes two buffers of the same size, and while the ejection data is being output from the one buffer to the head unit, the ejection data is transferred from the storage means to the other buffer. Is transferred. A liquid ejecting apparatus, wherein:

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