JP2012056125A - Recording apparatus and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mitigate degradation of image quality associated with inclination shifting when recording element arrays are arranged and shifted in a main scan direction.SOLUTION: A plurality of recording elements of a recording head is divided into a plurality of groups proximate to each other. One recording element is selected from each group. A plurality of blocks comprising the selected recording elements are driven in a time sharing manner. Inclination information in relation to a scan direction of the recording head of the recording element arrays is stored in a memory at the driving time. First, image data used by the recording element arrays among image data used for recording by a plurality of recording elements is stored for every array in a transfer buffer. On the basis of the inclination information stored in the memory, a sequence of offsetting a reading position of the image data read out from the transfer buffer is determined according to a driving sequence of blocks by time sharing driving and numbers of recording elements. The image data is read out from the determined offset reading position of the transfer buffer and transferred to the recording head.

Description

  The present invention relates to a recording apparatus that records an image on a recording medium by ejecting ink droplets from ink ejection ports provided in a recording head based on image data, and a control method therefor. More specifically, the present invention relates to a printing apparatus and a control method thereof capable of obtaining a good image by correcting the deviation of dot positions caused by the inclination of the printing head.

  A general ink jet recording apparatus includes a recording head in which ink discharge ports and recording elements which are energy generating means for discharging ink droplets, such as heaters and piezoelectric elements, are arranged in correspondence with each other. The ink jet recording apparatus moves the recording head in the scanning direction (main scanning direction) and ejects ink droplets on the recording area, and the recording medium in the direction intersecting the main scanning direction (sub scanning direction). The conveyance is repeated and an image is recorded on the recording medium.

Now, in each ink discharge port array (recording element array) of the recording head, the ink jet recording apparatus has a power capacity for discharging ink droplets simultaneously from all the ink discharge ports because of the cost increase of the power supply and the like. Have difficulty. Therefore, in order to avoid the above problem, each recording element is driven in a time-sharing manner. Here, the time-division driving will be described. In each ink discharge port array, the printing elements are divided into a plurality of groups, and the printing elements are assigned to different blocks in each group. Then, the recording elements of each block are sequentially driven at intervals, and all the recording elements are driven by making a round. This is repeated in the main scanning direction, and recording is performed in a recording area for one main scanning. Furthermore, it is known to change the time-division driving method depending on the nozzle arrangement and ejection characteristics. For example, in Patent Document 1, the accuracy of the position where ink droplets adhere to a recording medium is improved by dividing the order of time-division driving within a group into those driven by the nozzle in the first half and those driven in the second half. .
Further, in the ink jet recording apparatus, the recording head may be attached to the ink jet recording apparatus in an inclined manner due to an attachment error of the recording head with respect to the ink jet recording apparatus or an assembly error of the recording head. For this reason, a deviation in dot formation position corresponding to this inclination, so-called inclination deviation, may occur.

  When the tilt shift occurs, dots may be formed at positions deviating from the column where they should be originally arranged, leading to degradation of image quality. A method for correcting the inclination is proposed in Patent Document 2, for example. Patent Document 2 discloses a recording apparatus including a recording head that drives a recording element in a time-sharing manner. Patent Document 2 proposes a configuration that offsets the print data reading positions assigned to the number of printing elements designated by the correction value in order from the printing elements with the earlier ejection order in each group, in particular, according to the tilt deviation. Yes.

JP 2008-143066 A JP 2009-6676 A

  However, for example, when the arrangement of the nozzles of the recording head is not arranged in a line, but is arranged in a staggered manner with respect to the nozzle arrangement direction of the recording head, the method proposed in Patent Document 2 correctly corrects the inclination. I can't.

  FIG. 25 is a diagram showing the nozzle arrangement of the recording head in which the nozzles are arranged in a staggered manner in the nozzle arrangement direction and the dot positions recorded by the recording head. As shown in FIG. 25, since the recording head 11 has a staggered arrangement, two nozzle rows are arranged, and the discharge ports 13 are arranged with a gap of M between the nozzle rows. Here, the discharge ports are arranged for 128 nozzles.

  In the following, as shown in FIG. 25, a case will be described in which correction is performed by the method proposed in Patent Document 1 when the recording head 11 is tilted with respect to the scanning direction (main scanning direction) of the recording head.

  FIG. 26 is a diagram showing the dot arrangement, block number, and nozzle number formed on the recording medium 12 when the recording head is ideally attached to the recording apparatus and there is no tilt deviation. In FIG. 26, the recording head 11 is mounted on the recording apparatus in parallel with the conveyance direction (sub-scanning direction) of the recording medium 12 indicated by the arrow B, and the recording medium 12 is moved from left to right along the main scanning direction on the recording medium 12 by the arrow A. Go to and record. Further, the recording medium is conveyed from the top to the bottom in the figure in the direction of arrow B, with the lower side being the downstream side in the sub-scanning direction and the upper side being the upstream side in the sub-scanning direction. Black dots in the figure are dot arrangements actually formed on the recording medium. The white circles are dot arrangements with even nozzle numbers when the nozzle arrangement is arranged in a line, and the dot arrangements with odd nozzle numbers are the same as the black circles. The black circles with the same nozzle number with respect to the white circles are displaced in the dot arrangement by M (half pixel) in the opposite direction to the main scanning direction because the nozzle arrangement is displaced.

  At this time, the recording elements (not shown) arranged corresponding to the 128 ink discharge ports 13 of the recording head 11 are changed from group 0 (G0) to group 7 (G7) each consisting of 16 recording elements. Divide into 8 groups. Then, the recording elements are assigned to different blocks in each group, and driving is performed for each recording element of the same block. Here, the recording elements are divided into groups 16 to 7 in order from the recording elements upstream in the sub-scanning direction. In addition, as described in Patent Document 1, the order of the drive blocks is such that the odd nozzle number set that is M shifted from the even nozzle number set is driven in the first half and the even nozzle number set is driven in the second half. Yes. Specifically, the block numbers of 8 → 0 → 9 → 1 → 10 → 3 → 11 → 4 → 12 → 5 → 13 → 6 → 14 → 7 → 15 are assigned in order from the nozzle on the upstream side in the sub-scanning direction. Is driven in one cycle in the drive order of block numbers 0 → 1 → 2 →.

  FIG. 27 is a diagram showing the arrangement of dots when an inclination shift occurs when an image is recorded by a recording head having the same configuration as in FIG. It is assumed that the recording head 11 is attached to the recording medium 12 in a clockwise direction. As shown in FIG. 27, dots formed by printing elements assigned to the same block are formed shifted in the main scanning direction on the upstream side and the downstream side. Further, dots formed at positions deviating from the column that should be originally arranged are generated. For example, in group 1, for example, two dots of block numbers 0 and 8 are formed at positions that are out of the column where they should originally be arranged.

  According to Japanese Patent Application Laid-Open No. 2004-133620, the reading of recording data is changed in the driving order for the number of recording elements determined here.

  FIG. 28 is a diagram showing nozzle numbers, block numbers, print data (DATA), and corrected dot arrangements assigned to print elements in groups 0 to 7. Note that the dot arrangement shown in FIG. 28 schematically shows the arrangement of dots formed on the recording medium 12 when there is no tilt deviation. Here, the white squares indicate the dot arrangement of even-numbered nozzle numbers when the nozzle arrangement is arranged in one row, and only the first column of group 0. When the recording data reading position is changed by a correction value that specifies the number of recording data reading changes in each group, the dot arrangement is as shown in FIG. However, the actual dot formation position is shifted in the main scanning direction due to the tilt shift. The nozzle number is virtually assigned to each printing element, and 0 to 127 are assigned in order from the printing element on the downstream side in the sub-scanning direction.

  According to Japanese Patent Laid-Open No. 2004-260628, the print data reading positions assigned to the number of print elements designated by the correction value are offset in order from the print element having the earlier ejection order in each group in accordance with the tilt shift.

  Specifically, the correction value 2 is set for the group 1, and the read position of the recording data of the block 0 and the block 1 is changed at the timing of the original first to third columns to the second to fourth columns. . Similarly, the read position of the recording data up to block 3 in group 2, up to block 5 in group 3, and up to block 7 in group 4 is offset by one column and changed to the second to fourth columns. Similarly, the reading position of the recording data up to block 9 in group 5, up to block 11 in group 6, and up to block 13 in group 7 is offset by one column and changed to the second to fourth columns. However, in the groups 1 to 4, the dots of the block numbers 8 to 15 on the upstream side in the main scanning direction are not offset although the print data reading position is changed. For this reason, the dots are not missed as a whole. In the group 1, the most upstream nozzles in the main scanning direction have block numbers 8 and 0, but the offset nozzles are the block numbers 0 and 1, so the nozzle 8 upstream in the main scanning direction from the block number 1 Will remain.

  FIG. 29 is a diagram showing the dot arrangement actually formed on the recording medium by changing the reading position of the recording data as described in FIG. In FIG. 29, the white circles indicate dots that are formed when the recording data of the first column is assigned as it is without correction. In Patent Document 1, since the reading position of the recording data is changed in the driving order, there may be a dot that deviates from the column that should be originally arranged. For example, when attention is paid to the nozzle number 16 of group 1, the recording data is not moved although it deviates from the original column due to the inclination of the recording head 11. On the other hand, when attention is paid to the nozzle number 19 of group 1, there is a dot in the original column before the movement, but the recording data has been moved by the correction. The recorded data in the third column has also moved to a position outside the column.

  As described above, the correction method disclosed in Patent Document 1 has a problem in that when the nozzle arrangement is shifted in the main scanning direction and the order of the dot positions in the driving and main scanning directions is different, correction cannot be performed correctly.

  The present invention has been made in view of the above-described conventional example, and a recording apparatus capable of reducing deterioration in image quality due to an inclination shift when the recording element arrays are arranged shifted in the scanning direction of the recording head, and the recording apparatus The purpose is to provide a control method.

  In order to achieve the above object, the recording apparatus of the present invention has the following configuration.

  That is, a recording head in which a plurality of recording elements constituting a recording element array is shifted according to a predetermined pattern in a direction crossing the arrangement direction of the plurality of recording elements based on image data is arranged in the plurality of recording elements. The plurality of recording elements are divided into a plurality of groups adjacent to each other while scanning in a direction intersecting the arrangement direction of the plurality of groups, one recording element is selected from each of the plurality of groups, and the selected recording element is selected from each group A recording apparatus that performs recording by time-division driving a plurality of blocks configured by elements, and a recording buffer that stores the image data used when recording is performed by one scan of the recording head; Storage means for acquiring inclination information of the recording element array in the scanning direction of the recording head and storing the inclination information; and the plurality of recordings Of the image data used for recording by the child, the transfer buffer that stores the image data used in the recording element array for each column, and the image data that is read from the transfer buffer based on the tilt information stored in the storage means The order of offsetting the reading position of the block is determined according to the drive order of each block by time-division driving and the number of the printing element, and from the offset reading position of the transfer buffer determined by the determining means Transfer means for reading out image data and transferring it to the recording head.

  According to another aspect of the present invention, a plurality of recording elements constituting a recording element array are shifted and arranged according to a predetermined pattern in a direction intersecting the arrangement direction of the plurality of recording elements based on image data. The plurality of recording elements are divided into a plurality of groups adjacent to each other while the recording head is scanned in a direction intersecting the arrangement direction of the plurality of recording elements, and one recording element is selected from each of the plurality of groups. A method of controlling a recording apparatus that performs recording by time-division driving a plurality of blocks constituted by the selected recording elements from each group, wherein the recording element array is inclined with respect to the scanning direction of the recording head A step of acquiring information and storing the tilt information in a memory, and the image data used when recording is performed by one scan of the recording head. A step of storing in a recording buffer; a step of storing image data used in the recording element array among the image data used for recording by the plurality of recording elements in a transfer buffer; and a step of storing in the memory A step of determining the order of offsetting the reading position of the image data read from the transfer buffer based on the tilt information according to the driving order of each block by time-division driving and the number of the printing element; and the determined offset And a step of reading the image data from the reading position of the transfer buffer and transferring it to the recording head, and a step of recording by the recording head based on the transferred image data. Provide a method.

  Therefore, according to the present invention, there is an effect that it is possible to reduce deterioration in image quality due to a tilt shift when the print element arrays are arranged shifted in the scan direction of the print head.

1 is an external perspective view showing a schematic configuration of an ink jet recording apparatus which is a typical embodiment of the present invention. FIG. 3 is an ejection port array diagram of a recording head. FIG. 3 is a block diagram illustrating a configuration of a control circuit in the recording apparatus of the present invention. FIG. 6 is an arrangement diagram of data in a recording buffer. It is a figure explaining the operation | movement of HV conversion. 3 is a schematic diagram illustrating an internal configuration of a nozzle buffer 211. FIG. It is a block diagram which shows the structure inside ASIC. FIG. 6 is a schematic diagram illustrating an arrangement of print data held in a nozzle buffer. 3 is a diagram illustrating a configuration of a transfer buffer 213. FIG. It is a figure which shows the example of data in a block drive order data memory. FIG. 3 is a block diagram illustrating a recording head drive circuit. It is a drive timing diagram of a block drive signal. It is a figure which shows the correction value information (tilt information) hold | maintained in the table format in the correction amount memory | storage memory 217 which stores inclination information. FIG. 6 is a diagram illustrating a nozzle number, a block number, an offset number, print data, and a corrected dot arrangement after inclination correction in the first embodiment. FIG. 5 is a diagram illustrating a dot arrangement after correction with respect to an inclination shift according to the first embodiment. FIG. 10 is a diagram illustrating nozzle arrays, block numbers, corrected dot arrangements, and offset numbers of the recording heads 11b, 11c, and 11d according to the second embodiment. FIG. 10 is a diagram illustrating a dot arrangement after correction for an inclination shift in the recording head 11b according to the second embodiment. FIG. 10 is a diagram illustrating a dot arrangement after correction for a tilt shift in the recording head 11c according to the second embodiment. FIG. 10 is a diagram illustrating a dot arrangement after correction for a gap in a recording head 11d according to a second embodiment. It is a figure which shows the nozzle number after the inclination correction according to Example 3, a block number, an offset number, recording data, and dot arrangement. FIG. 10 is a diagram illustrating a corrected dot arrangement with respect to an inclination shift according to a third embodiment. It is a block diagram which shows the internal structure of ASIC206 according to Example 4. FIG. The correction information is set in the correction amount storage memory 217A according to the fourth embodiment. FIG. 10 is a diagram showing nozzle numbers, block numbers, print data, and dot arrangement in print head inclination correction according to a fourth embodiment. It is a figure which shows the nozzle number, block number, recording data, and dot arrangement in the inclination correction of the recording head according to a conventional example. FIG. 4 is a diagram illustrating dot arrangement, block numbers, and nozzle numbers when a recording head is ideally mounted and there is no tilt deviation. FIG. 5 is a diagram showing a dot arrangement and a block number when the recording head is mounted with an inclination. FIG. 6 is a diagram illustrating a nozzle number, a block number, print data, and a corrected dot arrangement of a print head. FIG. 4 is a diagram illustrating dot arrangement by correction of a tilt deviation of a recording head.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification, “record” (hereinafter also referred to as “print”) forms significant information such as characters and figures. Not only the case, but also a case where an image, a pattern, a pattern, or the like is widely formed on a recording medium or a medium is processed regardless of significance. It does not matter whether it has been made obvious so that humans can perceive it visually.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

The term “ink” should be broadly interpreted in the same way as the definition of “recording”. When applied to a recording medium, it forms an image, a pattern, a pattern, etc., or processes the recording medium. It represents a liquid that can be subjected to the treatment. Examples of the ink treatment include solidification or insolubilization of the colorant in the ink applied to the recording medium.
Further, the “recording element” (sometimes referred to as “nozzle”) is a general term for an ink discharge port, a liquid path communicating with this, and an element that generates energy used for ink discharge unless otherwise specified. Say it.

[Configuration of recording device]
FIG. 1 is an external perspective view showing a schematic configuration of an ink jet recording apparatus to which the present invention can be applied. The ink jet recording apparatus 100 includes an automatic feeding unit 101 that automatically feeds a recording medium such as paper into the apparatus main body. In addition, a transport unit 103 is provided that guides the recording medium sent one by one from the automatic feeding unit 101 to a predetermined recording position and guides the recording medium from the recording position to the discharge unit 102. Further, a recording unit that performs desired recording on the recording medium conveyed to the recording position, and a recovery unit 108 that performs recovery processing on the recording unit are provided.

  The recording unit includes a carriage 105 supported by a carriage shaft 104 so as to be movable in the main scanning direction indicated by an arrow X, and a recording head (inkjet recording head) 11 (not shown) that is detachably mounted on the carriage 105. . The recording head 11 has a recording element array in which a plurality of recording elements are arranged, and the main scanning direction of the arrow X corresponds to a direction intersecting with the arrangement direction of the recording elements. The present invention is premised on correcting the tilt error in the recording apparatus when the recording head 11 is mounted so that the main scanning direction of the arrow X and the arrangement direction of the recording elements cross obliquely.

  The carriage 105 is provided with a carriage cover 106 that engages with the carriage 105 and guides the recording head 11 to a predetermined mounting position on the carriage 105. Further, a head set lever 107 is provided that presses to engage the tank holder 113 of the recording head 11 to set the recording head 11 at a predetermined mounting position.

  A head set plate (not shown) is provided at the upper part of the carriage 105 so as to be rotatable with respect to the head set lever shaft, and is engaged with the recording head 11 by a spring. The head set lever 107 is configured to be mounted on the carriage 105 while pressing the recording head 11 by the spring force.

[Nozzle arrangement of recording head]
FIG. 2 is a diagram showing the nozzle arrangement of the recording head 11.

2A shows the arrangement (staggered pattern) of the ink discharge ports 13 on the ink discharge port surface 140 of the recording head 11. Each of the ink discharge port arrays 141, 142, 143, and 144 in which a plurality of ink discharge ports 13 are arranged includes 128 ink discharge ports 13 that discharge black, cyan, magenta, and yellow ink droplets.
The configuration of the recording head 11 may be, for example, a configuration in which the ink discharge port arrays 141, 142, 143, and 144 for each color include two rows in which the ink discharge ports 13 are alternately arranged in the sub-scanning direction. . Further, the black ink ejection port array 141 may have a larger number of ink ejection ports 13 than the other color ink ejection port arrays 142, 143, and 144.

  In the following description, the description will be given focusing on one ink discharge port array (for example, the black ink discharge port array 141), but the tilt deviation correction is similarly performed for the other ink discharge port arrays. Is possible.

  (B) shows the recording head 11 having an ink discharge port array 141 composed of 128 ink discharge ports 13. The upper ink discharge port 13 of the ink discharge port array 141 is downstream in the sub-scanning direction, and nozzle numbers 0 to 127 are virtually assigned in order from the ink discharge port 13 toward the upstream side. Nozzle number 0 and nozzle number 1 are shifted by ½ pixel in the main scanning direction. Further, 16 of these ink discharge ports 13 are divided into groups 0 to 7 in order from the smaller nozzle number, and blocks 0 to 15 are sequentially arranged from the recording elements corresponding to the ink discharge ports having the smaller nozzle numbers in each group. Shall be assigned. That is, the 16 ink discharge ports that are physically adjacent to each other of the 128 ink discharge ports (recording elements) are grouped into one group. In this way, recording elements to which block numbers are assigned are selected in a time-sharing manner, and images are recorded by driving the selected recording elements. In the following description, an example will be described in which an image is recorded by forming dots for three columns from the first column to the third column using all the ink ejection ports 13 of the recording head 11. .

[Outline of control configuration of recording device]
FIG. 3 is a block diagram illustrating a configuration of a control circuit in the inkjet recording apparatus 100. In the inkjet recording apparatus 100, 201 is a CPU, and 202 is a ROM that stores a control program executed by the CPU 201. The raster unit image data received from the host 200 is first stored in the reception buffer 203. The image data stored in the reception buffer 203 is compressed to reduce the amount of transmission data from the host 200. Therefore, the image data is decompressed by the CPU 201 or a compressed data decompression circuit (not shown) and stored in the recording buffer 204 as the first image data storage means. The recording buffer 204 is, for example, a DRAM. The format of data stored in the recording buffer 204 is raster format data. The recording buffer 204 has a capacity capable of storing data of the number of rasters corresponding to the width to be recorded in one scan.

  The image data stored in the recording buffer 204 is subjected to HV conversion processing by the HV conversion circuit 205 and stored in the nozzle buffer 211 provided in the ASIC 206. In other words, column format data is stored in the nozzle buffer 211. The format of this data corresponds to the nozzle arrangement. The nozzle buffer 211 is, for example, an SRAM.

  FIG. 4 is a diagram schematically showing the arrangement of image data in the recording buffer 204.

  The storage positions in the recording buffer 204 are addresses 000 to 0fe corresponding to 128 recording elements in the vertical direction, and memory areas having addresses corresponding to the product of the resolution and the size of the recording medium in the horizontal direction. This address is displayed in hexadecimal notation as indicated by “h” in the figure. Here, if the resolution is 1200 dpi and the recording medium size is 8 inches (inch), the memory area can store 9600 dots of data.

  Print data corresponding to the print element with nozzle number 0 is held at b0 of address 000 in FIG. Record data to be recorded in the next column of nozzle number 0 is held in b1 next to b0 at address 000, and similarly, record data to be recorded in the next column is held as it moves in the horizontal direction. It is a configuration. Similarly, the recording data of the recording element with the nozzle number 127 is held at the address 0fe.

  In this way, print data corresponding to print elements having the same nozzle number is held at each address of the print buffer 204. However, in practice, the first column is recorded based on b0 recording data from addresses 000 to 0fe, and then the second column is recorded based on b1 recording data from addresses 000 to 0fe. Therefore, the HV conversion circuit 205 converts the recording data stored in the recording buffer 204 in the raster direction into HV and stores it in the nozzle buffer 211 in the column direction.

  FIG. 5 is a diagram showing the operation of HV conversion. The HV conversion is performed in a data unit of 16 bits × 16 bits. Data b0 from address N + 0 to N + 1E from the recording buffer 204 is written to address M + 0 in the nozzle buffer 211. Next, the data b1 from the recording buffer 204 to addresses N + 0 to N + 1E is written to the address M + 2 of the nozzle buffer 211. Thereafter, the same processing is performed. Thus, the read operation and the write operation are repeated 16 times. Thereby, one HV conversion is performed. The HV conversion is performed on a group basis, and is performed in order from group 0 (G0) to group 7 (G7).

  FIG. 6 is a diagram showing the internal configuration of the nozzle buffer. Since HV conversion is performed during the recording operation, two banks are provided as shown in FIG. 6 so that the writing operation to the nozzle buffer and the reading operation are exclusive operations. One bank has an area that can store 16 columns. When this writing is performed to bank 0, reading is performed from bank 1, and when writing is performed to bank 1, reading is performed from bank 0.

  Next, a configuration for sequentially driving the time-divided recording elements will be described with reference to an internal block diagram of the ASIC 206 shown in FIG.

  FIG. 8 is a schematic diagram showing the arrangement of print data held in the nozzle buffer 211. As shown in FIG. 8, the data rearrangement circuit 212 arranges the recording data held in the nozzle buffer 211 into recording data for each block number to be recorded at the same time and writes it in the transfer buffer 213. It is a replacement circuit. As data stored in the transfer buffer 213, data corresponding to nozzles having the same block number is stored at the same address. Note that the transfer buffer is configured by, for example, an SRAM.

  FIG. 9 is a diagram illustrating the configuration of the transfer buffer 213. At addresses 0 to f, recording data of blocks 0 to 15 are held in order. Block 0 holds b0 recording data from group 0 (G0) to group 7 (G7). Similarly, block 1 holds b1 recording data from group 0 to group 7. .

  As shown in FIG. 9, the transfer buffer 213 is composed of three banks with 16 blocks of recording data as one bank so that the writing operation and the reading operation are exclusive operations. When writing is performed to bank 0, reading is performed from bank 1 and bank 2. When writing is performed to bank 1, reading is performed from bank 2 and bank 0. When writing is performed to bank 2, reading is performed from bank 0 and bank 1. Each bank holds recording data corresponding to one row of recording element rows, and the transfer buffer 213 holds recording data for three rows of recording element rows. Then, using two banks at the time of reading, the recording data for two columns of the recording element column is read. The reason for this will be explained later.

  Returning to the description of FIG. 7, the transfer number counter 216 is a counter circuit that counts the number of recording timing signals, and is incremented for each recording timing signal. The transfer counter counts from 0 to 15 and returns to 0. Further, the transfer number counter 216 counts the bank value of the transfer buffer 213, and when the transfer number counter is counted 16 times, the bank value is incremented by +1.

  In the block drive order data memory 214, the order in the case of sequentially driving the recording elements of the block numbers 0 to 15 divided into 16 is recorded at addresses 0 to 15. When driving sequentially from 0, they are stored in the order of 0 → 1 → 2.

  For example, the recording data transfer circuit 219 increments the transfer number counter 216 using a recording timing signal generated based on an optical linear encoder as a trigger. The output timing of the recording timing signal is synchronized with the output timing of the latch signal. The data selection circuit 215 reads the value in the block drive order data memory 214 and the recording data corresponding to the bank value from the transfer buffer 213 with the recording timing signal as a starting point. The recording data corrected according to the correction amount held in the correction amount storage unit 217 is transferred to the recording head 11 in synchronization with the data transfer CLK signal (HD_CLK) generated by the data transfer CLK generation unit 218. Forward. For this transfer, the recording data transfer circuit 219 includes a shift register that operates in synchronization with HD_CLK.

  FIG. 10 is a diagram illustrating an example of block drive order data written in addresses 0 to 15 of the block drive order data memory 214. In FIG. 10, block data indicating block 0 and block 1 are stored at address 0 and address 1 of the block drive order data memory 214, respectively. Similarly, block data indicating blocks 2 to 15 are sequentially stored at addresses 2 to 15.

  The data selection circuit 215 uses the recording timing signal as a trigger to read block data 0000 (here, a numerical value indicating block 0) as a block enable signal from address 0 of the block drive order data memory 214. Then, the recording data corresponding to the block data 0000 is read from the transfer buffer 213, and the recording data is transferred to the recording head 11 via the recording data transfer circuit 219.

  Similarly, block data 0001 (here, a numerical value indicating block 1) is read as a block enable signal from address 1 of the block drive order data memory 214 at the next recording timing signal. Then, the recording data corresponding to the block data 0001 is read from the transfer buffer 213 and transferred to the recording head 11.

  Similarly, block data is sequentially read from address 2 to address 15 of the block drive order data memory 214 using the next recording timing signal as a trigger. Then, the recording data corresponding to each block data is read from the transfer buffer 213 and transferred to the recording head 11.

  In this way, the recording data transfer circuit 219 reads block data set at addresses 0 to 15 in the block drive order data memory 214. Then, recording data corresponding to each block data is read from the transfer buffer 213 and transferred to the recording head 11 to perform recording for one column. That is, when 16 recording timing signals are output, block data for one column is read from the transfer buffer 213.

  FIG. 11 shows a drive circuit provided in the recording head 11. The drive circuit divides and drives the 128 recording elements 114 into 16 blocks, and drives the 16 recording elements assigned to the same block. Data and signals to the drive circuit are sent from the recording data transfer circuit 219 shown in FIG. The recording data signal 313 is sent by serial transfer to the recording head 11 by the HD_CLK signal 314. The recording data signal 313 is received by the 16-bit shift register 301 and then latched at the rising edge of the latch signal 312 by the 16-bit latch 302. The block is designated by the block enable signal 310 of 4 bits, and the recording element 114 of the block designated by the decoder 303 is selected.

  Only the recording element 114 specified by both the block enable signal 310 and the recording data signal 313 is driven by the heater driving pulse signal 311 output from the AND gate 305, and recording is performed by ejecting ink droplets.

  FIG. 12 is a diagram showing the drive timing of the block enable signal 310. In the divided block selection circuit, the block enable signal 310 can be generated based on the block drive order data stored in the block drive order data memory 214. Therefore, as shown by the block enable signal 310 in FIG. 12, the divided block selection circuit sequentially designates the block drive order generated by the block drive order data memory 214 as 16 blocks from the block 0 to the block 15. Is set to Therefore, in the forward recording at the time of unidirectional recording and bidirectional recording, the block enable signal 310 indicating the drive timing is represented by block 0 → 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → 10 → 11. Drive in the order of drive of 12 → 13 → 14 → 15. The block enable signal 310 is generated so that each block is designated at equal intervals in one cycle.

  A test patch is recorded on a recording medium, and the optical characteristics of the test patch are measured using an optical sensor. The occurrence of tilt deviation can be detected from the measurement result.

  Next, several embodiments of a recording control method using the recording apparatus and the recording head having the above-described configuration will be described.

  Here, by measuring the image formed by the recording head using an optical sensor, the displacement amount of the dot arrangement with respect to the main scanning direction is obtained from the positions of the dots formed by the recording elements at both ends of the recording element array. To do. Then, the recording element whose storage position is changed when the recording data is stored in the recording buffer 204 is determined so that the dot formation position is offset by one column in the main scanning direction according to the deviation amount. Information about the recording element whose storage position is changed is set in the correction amount storage memory 217 as correction information. Here, the correction information may be information for specifying the recording element whose storage position is changed. However, the correction information in this embodiment is the correction information based on the number of recording elements of the recording data for each group. Yes.

  FIG. 13 is a diagram showing correction value information (tilt information) held in a table format in the correction amount storage memory 217 for storing tilt information. Here, information (inclination correction amount) indicating how many recording timing signals are corrected in the 16-division drive is held. Here, 0 for group 0, 2 for group 1, 4 for group 2, 6 for group 3, 8 for group 4, 10 for group 5, and for group 6 12 and 14 for group 7 are set as correction information.

  In this table, the reference group 0 has no recording element whose recording data storage position is changed, and 0 is set. For group 1 and later, the number of recording elements whose recording data storage position is changed is determined for each group as a correction value. As a method for determining such correction information, there is a method in which the recording apparatus holds a plurality of table information in advance so that the correction information can be changed in accordance with the information regarding the above-described tilt deviation. Alternatively, the number of recording elements for the group 7 is determined from the information on the tilt shift, and the number of recording elements for the group located in the middle is derived by simple calculation from the number of recording elements for the group 0 and the number of recording elements for the group 7. May be.

  In the first embodiment, the correction value is 0 based on the group 0. However, the reference group may be any group. For example, if group 4 is used as a reference, -8 is set for group 0, -6 is set for group 1, -4 is set for group 2, -2 is set for group 3, and 0 is set for group 4. To do. Further, 2 for group 5, 4 for group 6, and 6 for group 7 can be set as correction information.

  In this way, an image is recorded on the recording medium by the recording data stored in the nozzle buffer 211 based on the correction information set in the correction amount storage memory 217.

  FIG. 14 is a diagram showing nozzle numbers, block numbers, offset numbers, print data, and dot arrangements assigned to print elements of groups 0 to 7 of the print head 11. In FIG. 14, the print data is print data stored in the nozzle buffer 211, and the dot arrangement is formed on the print medium when printing is performed based on the print data stored in the nozzle buffer 211 when there is no tilt deviation. The dots are schematically shown.

  In FIG. 14, the white squares indicate the dot arrangement of even nozzle numbers when the nozzle arrangement is arranged in one row, and only the first column of group 0. When the print data read position is changed, the correction value for designating the number of print data read changes in each group is the dot arrangement shown in FIG. 14 if there is no tilt deviation, but the actual dot formation position is tilted. The position is shifted in the main scanning direction by the shift. The nozzle number is virtually assigned to each printing element, and 0 to 127 are assigned in order from the printing element on the downstream side in the sub-scanning direction.

  The drive order in this recording head is such that an odd nozzle number set that is shifted by 1/2 pixel is driven earlier than an even nozzle number set. Then, block numbers of 8 → 0 → 9 → 1 → 10 → 3 → 11 → 4 → 12 → 5 → 13 → 6 → 14 → 7 → 15 are assigned in order from the nozzle on the upstream side in the sub-scanning direction. Paying attention to the dot arrangement of the first column of group 0, by driving the nozzle assigned by the block number in the nozzle arrangement of the first embodiment, the dot arrangement biased to 1/2 pixel as shown by the square It becomes. Specifically, the dots corresponding to the even nozzle numbers that should have been driven in the latter half are arranged at the same position in the main scanning direction as the dots corresponding to the odd nozzle numbers by the nozzle arrangement. Therefore, the order of driving and the order of dot arrangement in the main scanning direction are different.

  For this reason, in this embodiment, the order in which the print data reading position is offset according to the tilt deviation is determined according to the block number assignment (drive order) and the nozzle arrangement. The offset of the recording data is performed from dots arranged on the upstream side in the main scanning direction. For this reason, in this embodiment, the offset numbers in the order of 8 → 0 → 9 → 1 → 10 → 2 → 11 → 3 → 12 → 4 → 13 → 5 → 14 → 6 → 15 → 7 from the upstream nozzle in the sub-scanning direction. Is assigned. Then, the nozzle to which the recording data is offset is selected in the order of offset number 0 → 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → 10 → 11 → 12 → 13 → 14 → 15. The

  Specifically, as shown in FIG. 13, the correction value 2 is set for the group 1, and the recording data of the block 8 with the offset number 0 and the block 0 with the offset number 1 are from the original first to third columns. The read position is changed at the timing of the second to fourth columns. Similarly, in group 2, the recording data read positions of block 8 with offset number 0, block 0 with offset number 1, block 9 with offset number 2 and block 1 with offset number 3 are offset by one column and 2-4. Changed to column. Further, in the group 3, the read position of the recording data is offset by one column in the block 8, the block 0, the block 9, the block 1, the block 10, and the block 3, and is changed to the second to fourth columns. Similarly, the recording data of group 4 to group 7 are offset in the order in which the reading position is offset by the number of correction values.

  FIG. 15 is a diagram showing the arrangement of dots formed on the recording medium 12 by inclination deviation correction according to this embodiment. In FIG. 15, white dots indicate dots formed when the inclination deviation correction according to this embodiment is not performed.

  When an inclination shift occurs, dots are formed at positions deviating from the column area that should be originally arranged. The dots are sequentially removed from the upstream side in the main scanning direction, and increase with the group 0 as a reference, such that the group 0 is 0, the group 1 is 2, and the group 2 is 4. In the inclination deviation correction according to this embodiment, the recording data can be offset from the dot on the upstream side in the main scanning direction with respect to the position of the ink droplet attached to the recording medium by making the order of offset different from the driving order. Thereby, it can fit in the column area which should be arranged originally.

  Therefore, it is possible to suppress the deterioration of the recorded image quality by performing the inclination shift correction according to the embodiment described above.

  In this embodiment, an inclination correction method in a recording head having various patterns of nozzle arrays will be described.

  FIG. 16 is a diagram showing a nozzle arrangement, a block number, a dot arrangement, and an offset number according to the second embodiment. First, the nozzle arrangement will be described.

  In the “three rows” nozzle row of the recording head 11 b, the nozzles are arranged with a shift of 1/3 pixels in order of one nozzle at three locations upstream, midstream, and downstream with respect to the main scanning direction A. In the “2-nozzle staggered” of the recording head 11c, the nozzles are alternately arranged by ½ pixel every two nozzles. The “head” of the recording head 11d is arranged in the upstream, middle, and downstream locations in the main scanning direction A, and the nozzles are arranged with a shift of 1/3 pixel in the order of upstream → middle flow → downstream → middle flow → upstream. Yes. All the nozzle arrangements are shown with only 16 nozzles, but 128 nozzles are arranged in a similar pattern.

  Next, block number assignment will be described. Each nozzle arrangement illustrates the assignment of block numbers to nozzle numbers. Since the driving is performed in the order of the block numbers, each nozzle is driven in the order of the assigned block numbers.

  Next, the dot arrangement when driven in the driving order will be described. Here, every nozzle array shows recording data for two columns. The white circles are dot arrangements with even nozzle numbers when the nozzle arrangement is arranged in a line, and the dot arrangements with odd nozzle numbers are the same as the black circles. The positions of the dots are displaced due to the displacement of the nozzle array in the main scanning direction. The final dot arrangement is placed within 1/3 pixel in the “3” nozzle row of the recording head 11b, and in the “2 nozzle staggered” nozzle row of the recording head 11c and the “bow” nozzle row of the recording head 11d. It is placed within 1/2 pixel.

  Next, the order in which recording data is offset according to the inclination will be described. FIG. 16 shows an offset number for each nozzle number. When the inclination is corrected, the recording data is moved in the order of the offset numbers assigned to the nozzles. The order is in order from the upstream side in the main scanning direction A of the dot arrangement.

  17, 18, and 19 are diagrams illustrating dot arrangements when the print heads of the nozzle array of “3 rows”, “2-dot zigzag”, and “Koji” are tilted and corrected accordingly. In FIG. 17, it is assumed that an inclination deviation occurs such that the deviation (L) in the main scanning direction between the most upstream nozzle and the most downstream nozzle of the recording head 11 b is L = 1/3 pixel. Further, in FIGS. 18 and 19, an inclination deviation occurs such that the deviation (L) in the main scanning direction between the most upstream nozzle and the most downstream nozzle of the recording heads 11 c and 11 d is L = 1/2 pixel. Shall.

  The correction value is the same as that shown in FIG. 13 described in the first embodiment. In these FIG. 17 to FIG. 19, white circles are dot arrangements when the recording data is not moved. (A) is a dot arrangement in the case where correction is performed according to the method of Patent Document 2, and movement of recording data with respect to the correction value is performed in the order of driving. (B) is a dot arrangement when correction is performed according to the method of this embodiment, and the print data is moved with respect to the correction values in the order of the offset numbers assigned to the nozzles.

  In each of FIGS. 17 to 19, when (A) and (B) are compared, in (A), the dots formed out of the column originally arranged due to the inclination of the nozzle cannot be corrected correctly, and the original arrangement is made. Dot is recorded outside the column. On the other hand, in (B), dots formed out of the column where they are originally arranged due to the inclination of the nozzle can be corrected in order from the upstream side in the main scanning direction A. As a result, it is possible to record with dots stored in the originally arranged columns.

  Therefore, according to the embodiment described above, it is possible to reduce the deterioration of image quality due to the tilt deviation in various nozzle arrangements arranged in the main scanning direction.

  In the first and second embodiments, distributed driving is performed in which time-division driving is performed in such an order that ink droplets are not ejected continuously from adjacent nozzles. In the third embodiment, a tilt correction method in the case where sequential driving is performed in which the nozzles are sequentially driven from the upstream side nozzle in the sub-scanning direction will be described.

  The recording head of this embodiment is the same as that of Embodiment 1, has the same arrangement as the nozzle arrangement of the recording head 11, and the displacement amount M of the nozzle in the main scanning direction is 1/2 pixel.

  Similarly to the first embodiment, the correction values in this embodiment are as shown in FIG.

  FIG. 20 is a diagram showing nozzle numbers, block numbers, print data, and dot arrangements assigned to printing elements in groups 0 to 7. In FIG. 20, the white squares indicate the dot arrangement of even-numbered nozzle numbers only in the first column of group 0 when the nozzle arrangement is not staggered but arranged in one row. The correction value for designating the number of print data read changes in each group is the dot arrangement shown in FIG. 20 if there is no tilt deviation when the print data read position is changed. The nozzle number is virtually assigned to each printing element, and 0 to 127 are assigned in order from the printing element on the downstream side in the sub-scanning direction.

  In this embodiment, the block numbers are assigned in order from the nozzles on the upstream side in the sub-scanning direction of the nozzles for sequential driving. Specifically, block numbers are assigned in the order of 0 → 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → 10 → 11 → 12 → 13 → 14 → 15 from the nozzle on the upstream side in the sub-scanning direction. It has been. The offset number assigned to each nozzle in the group is 0 → 5 → 1 → 7 → 2 → 9 → 3 → 11 → 4 → 12 → 6 → 13 → 8 → 14 → 10 → 15 from the upstream nozzle in the sub-scanning direction. is there.

  Specifically, the correction value 2 is set for the group 1, and the read position of the recording data of the block 0 and the block 2 from the original column is changed. Similarly, group 2 includes block 0, block 2, block 4, and block 6, and group 3 includes block 0 to block 2, block 4, block 6, and block 8, and the recording data read position is offset by one column. Changed to the fourth column. Similarly, the recording data of group 4 to group 7 are offset in the order of the offset number.

  FIG. 21 is a diagram illustrating the arrangement of dots formed on the recording medium 12 by the inclination shift correction according to the third embodiment. In FIG. 21, white dots indicate dots formed when the inclination deviation correction according to this embodiment is not performed.

  When an inclination shift occurs, dots are formed at positions deviating from the column area that should be originally arranged. However, by moving the recording data by the number determined for each group in the order of the above-mentioned offset number for each group, it fits within the column to be originally arranged.

  Therefore, according to the embodiment described above, it is possible to reduce the deterioration in the recording image quality due to the tilt shift even when the nozzle array is sequentially driven by being shifted in the main scanning direction.

  In the first to third embodiments, the displacement of the nozzle arrangement in the main scanning direction is less than one pixel. In the fourth embodiment, a case where the displacement is one pixel or more will be described.

  The recording head used in this embodiment has the same arrangement as the nozzle arrangement of the recording head 11, and the displacement amount (M) of the nozzle in the main scanning direction is 3/2 pixels.

  FIG. 22 is a block diagram showing an internal configuration of the ASIC 206 according to the fourth embodiment. The difference from the configuration of the ASIC 206 shown in FIG. 6 is that a correction amount storage memory 217A is added, and the other configurations are the same. In this embodiment, the data selection circuit 215 performs correction according to the correction values held in the two correction amount storage memories 217 and 217A. Then, the corrected recording data is transferred to the recording head 11 in synchronization with the data transfer CLK signal (HD_CLK) generated by the data transfer CLK generation unit 218. The setting of the correction amount storage memory 217A changes depending on the arrangement of the nozzles, and there is one setting in the recording apparatus on which one recording head is mounted.

  FIG. 23 is a diagram showing correction information set in the correction amount storage memory 217A. As shown in FIG. 23, the number of columns in which the recording data is offset with respect to the nozzle number is set. When the number of offset columns as the correction value is positive, the print data is offset downstream in the main scanning direction, and when it is negative, the recording data is offset upstream in the main scanning direction. In this embodiment, 1 is set for the even nozzles based on the odd nozzle number, but the even nozzle number may be used as a reference, and a number other than 1 may be set according to the displacement amount of the nozzle row. There is also.

  FIG. 24 is a diagram showing nozzle numbers, block numbers, print data, and corrected dot arrangements assigned to print elements in groups 0 to 7.

  When attention is paid to the first and second columns of group 0 (G0) shown in FIG. 24, the nozzle array is driven by the block number in a row without performing correction based on the correction information stored in the correction amount storage memory 217A. In this case, the dot arrangement in the second column is a white circle. However, when correction is performed using the correction information, the print data is offset by one column upstream in the main scanning direction, and therefore, instead of the dot recorded at the position of the white circle, the print data is placed at the position indicated by the arrow in the first column. Dots based on the recording data are recorded. Considering the shift in the main scanning direction of the nozzle arrangement from there, the dot arrangement is shifted to the upstream side in the 3/2 pixel main scanning direction, so that the dot arrangement represented by a square is obtained.

  In the group 1 (G1) to the group 7 (G7), the recording data is shifted based on the inclination information. The method for shifting the recording data based on the tilt information is the same as in the first embodiment. Then, the final dot recording position becomes the same as that in the first embodiment, and the effect on the tilt can be obtained as in the first embodiment.

  Therefore, according to the embodiment described above, it is possible to reduce deterioration in image quality due to a tilt shift in a nozzle array that is shifted by one pixel or more in the main scanning direction.

Claims (8)

An array of the plurality of recording elements, in which a plurality of recording elements constituting the recording element array are shifted in accordance with a predetermined pattern in a direction intersecting the array direction of the plurality of recording elements based on image data While scanning in a direction crossing the direction, the plurality of recording elements are divided into a plurality of groups adjacent to each other, one recording element is selected from each of the plurality of groups, and the selected recording element is selected from each group A recording apparatus that performs recording by time-sharing driving a plurality of configured blocks,
A recording buffer for storing the image data used when recording is performed by one scan of the recording head;
Storage means for acquiring inclination information of the recording element array in the scanning direction of the recording head, and storing the inclination information;
Among the image data used for recording by the plurality of recording elements, a transfer buffer for storing image data used in the recording element array for each column;
Determination that determines the order in which the reading position of the image data read from the transfer buffer is offset based on the tilt information stored in the storage means in accordance with the driving order of each block by time-division driving and the number of printing elements Means,
A recording apparatus comprising: transfer means for reading out image data from the offset reading position of the transfer buffer determined by the determining means and transferring the read image data to the recording head.   The recording apparatus according to claim 1, wherein the predetermined pattern is a staggered pattern, a three-row pattern, a two-nozzle staggered pattern, or a cross-shaped pattern.   The recording apparatus according to claim 1, wherein time-division driving is performed in order from recording elements at end portions of a plurality of recording elements included in each of the plurality of groups.   The recording apparatus according to claim 1, wherein a displacement of the recording element in the scanning direction of the recording head is less than one pixel of a recorded pixel.   The recording apparatus according to claim 1, wherein the displacement of the recording element in the scanning direction of the recording head is one pixel or more of pixels to be recorded.   The recording apparatus according to claim 1, wherein the tilt information is acquired from an image formed by recording elements at both ends of the recording element array by an optical sensor.   The recording apparatus according to claim 1, wherein the recording head is an ink jet recording head. An array of the plurality of recording elements, in which a plurality of recording elements constituting the recording element array are shifted in accordance with a predetermined pattern in a direction intersecting the array direction of the plurality of recording elements based on image data While scanning in a direction crossing the direction, the plurality of recording elements are divided into a plurality of groups adjacent to each other, one recording element is selected from each of the plurality of groups, and the selected recording element is selected from each group A method of controlling a recording apparatus that performs recording by driving a plurality of configured blocks in a time-sharing manner,
Obtaining tilt information of the print element array in the scan direction of the print head, and storing the tilt information in a memory;
Storing the image data used in recording in one scan of the recording head in a recording buffer;
Of the image data used for recording by the plurality of recording elements, storing image data used in the recording element array in a transfer buffer for each array;
Determining the order of offsetting the reading position of the image data read from the transfer buffer based on the tilt information stored in the memory according to the driving order of each block by time-division driving and the number of printing elements;
Reading image data from the determined read position of the transfer buffer and transferring it to the recording head;
And recording with the recording head based on the transferred image data.

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