JP2011088391A - Recorder, and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recorder which can suppress the deterioration of image quality by reducing the deviation of tilting, and a control method for the same. <P>SOLUTION: Two column data are read, and the column data of either column is chosen corresponding to a recording element activated by time sharing based on inclination information corresponding to each group of a recording head and a block number at the time of activating the recording head by time sharing. A recording data signal is formed from the chosen column data and transmitted to the recording head, and then the recording head is activated by time sharing. <P>COPYRIGHT: (C)2011,JPO&INPIT

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 recording apparatus capable of obtaining a good image by correcting the deviation of the dot formation position caused by the inclination of the recording head and the like, and a control method thereof.

  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. An ink jet recording apparatus repeats a recording scan for ejecting ink droplets on a recording area while moving a recording head in the main scanning direction, and a conveyance of the recording medium in a sub-scanning direction intersecting the main scanning direction. Record an image on

  In each ink discharge port array of the recording head, it is difficult for the ink jet recording apparatus to have a power supply capacity for discharging ink droplets simultaneously from all the ink discharge ports for reasons such as an increase in power supply cost. Therefore, each recording element is time-division driven. This time-division driving will be described. The printing elements are divided into a plurality of groups in each ink discharge port array, and different blocks are assigned to the printing elements in the group in each group. Then, the recording elements are sequentially driven for each block, and all the recording elements are driven by one cycle. By repeating such time-division driving at the time of recording scanning in the main scanning direction, recording is performed in a recording area for one scanning.

  In addition, in an ink jet recording apparatus, the recording head may be inclined with respect to the ink jet recording apparatus due to a mounting error when mounting the recording head on the ink jet recording apparatus or an error when assembling the recording head. For this reason, a deviation in dot formation position corresponding to this inclination, so-called inclination deviation, may occur.

  The tilt deviation will be described with reference to FIGS.

  FIG. 22 shows an arrangement of dots formed on the recording medium 12 when the recording head is ideally mounted on the ink jet recording apparatus and there is no tilt deviation. In FIG. 22, the recording head 11 is mounted on the ink jet recording apparatus so that the sub-scanning direction of the arrow B and the ink ejection port array are parallel to each other, and the recording medium 11 is moved from left to right along the main scanning direction indicated by the arrow A on the recording medium 12. Go to and record. The recording medium 12 is conveyed in the direction of arrow B, and the upper side in the figure is the upstream side in the sub-scanning direction, and the lower side is the downstream side in the sub-scanning direction.

  Further, the recording elements corresponding to the 128 ink discharge ports 13 of the recording head 11 are divided into 8 groups, group 0 to group 7, each consisting of 16 adjacent recording elements. In each group, a different block is assigned to each recording element in the group, and the recording elements in the same block are sequentially driven. Here, the recording elements are divided into groups 0 to 7 in order of 16 from the upstream side in the sub-scanning direction. In each group, blocks 0 to 15 are assigned in order from the recording element on the upstream side in the sub-scanning direction. In this way, the recording element is driven in one cycle in the drive order of block 0 → 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → 10 → 11 → 12 → 13 → 14 → 15. Is done.

  If there is no tilt shift, dots formed by one cycle of driving by the printing elements in blocks 0 to 15 are formed in the same column (one pixel width) region. FIG. 33 shows the dots formed on the recording medium when the recording element is driven in the order of blocks 0 to 15 and image data for three columns from the first column to the third column is assigned to the recording element. The arrangement is shown. In this way, dots formed by one cycle of driving by the printing elements of each group are arranged in a predetermined area (same column), and an image with high printing quality can be obtained.

  On the other hand, FIG. 23 shows the arrangement of dots when the recording head is mounted to be inclined with respect to the ink jet recording apparatus and an inclination shift occurs when an image similar to FIG. 22 is recorded. The dots formed by the recording elements of groups 4 to 7 in the figure are shown for four columns, but here, the dots for only the left three columns in the figure are formed by the recording elements of each group. Will be described. As shown in FIG. 23, dots formed by printing elements assigned to the same block are formed shifted in the main scanning direction between the upstream side and the downstream side. Furthermore, dots formed at positions deviating from the columns that should be originally arranged are formed. For example, in group 2, the four dots from block 0 to block 3 are formed at positions outside the column area that should be originally arranged. As described above, when an inclination shift occurs, dots are formed at positions deviating from the region where they should originally be arranged, and the image quality is degraded.

  In view of this, a technique has been proposed in which the ink jet recording apparatus is provided with means for detecting information on tilt deviation, and the tilt deviation is corrected by changing the ejection timing of the recording head based on the detected information on tilt deviation.

  Japanese Patent Application Laid-Open No. 2004-26883 discloses an ink jet recording apparatus that ejects ink droplets by time-division driving a recording element by changing the position of image data read from a recording buffer for each group according to an inclination shift, and ejecting timing of a recording head. The contents to change are described.

Japanese Patent Application Laid-Open No. 2004-09489

  As described above, in the correction method of Patent Document 1, the amount of deviation in the dot arrangement in the main scanning direction can be reduced, but the dots arranged in the area to be originally arranged are arranged at positions deviating from the area to be originally arranged. In some cases, the tilt deviation is not sufficiently reduced.

  SUMMARY An advantage of some aspects of the invention is to provide a recording apparatus and a control method thereof that can improve the problems associated with the above-described correction method, reduce the tilt deviation, and suppress deterioration in image quality.

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

  That is, a recording apparatus that performs recording by scanning a recording head having a recording element array in which a plurality of recording elements are arranged based on image data, and is used when recording is performed by scanning the recording head And a recording buffer that stores a predetermined number of recording elements so that adjacent recording elements are included in different blocks among the plurality of recording elements, and driving means that performs time-division driving for each block A first memory that holds inclination information corresponding to a group in the scanning direction of the recording head of the recording element array, and a second memory that stores a block number indicating a block driving order for the time-division driving A third memory for storing, as column data, recording data for a plurality of columns among the image data stored in the recording buffer; Based on the tilt information held in the first memory and the block number stored in the second memory, the column data for two consecutive columns is read from the third memory, and the read column data A generating unit that selects column data of any column corresponding to the recording elements that are time-division driven by the driving unit, and generates a recording data signal used for recording by the recording head; and the generating unit And a transfer means for transferring the recording data signal generated by the above to the recording head.

  According to another invention, a control method applied to the apparatus having the above-described configuration is provided.

  Therefore, according to the present invention, since the print data can be selected and changed with respect to the column direction corresponding to the print elements that are driven in a time-sharing manner, it is possible to suppress deterioration in image quality due to a tilt shift in the scan direction of the print head. There is an effect that can be done.

1 is an external perspective view showing an outline of a configuration of an ink jet recording apparatus that is a typical embodiment of the present invention. FIG. 2 is a diagram illustrating a nozzle configuration of the recording head. It is a flowchart which shows the outline of a dot inclination shift value detection. It is a figure which shows the test pattern formed in the recording medium. It is a figure which shows the test patch for inclination detection. It is a figure which shows dot arrangement | positioning at the time of inclination shift | offset | difference generation | occurrence | production. It is a figure which shows the test patch for inclination detection. It is a figure which shows the example of a setting of the inclination correction amount in a correction amount memory | storage means. It is a figure which shows the dot arrangement | positioning according to the Example of this invention. FIG. 6 is a diagram illustrating an arrangement of dots formed on a recording medium by inclination deviation correction according to an embodiment of the present invention. FIG. 3 is a block diagram illustrating a control configuration of a recording apparatus. It is a figure which shows typically the image data stored in the recording buffer. It is a figure explaining the operation | movement of HV conversion. It is a time chart of the signal which a recording timing generation part generates. It is a figure which shows the structure of SRAM912 for column data storage. FIG. 3 is a block diagram illustrating a detailed configuration of a block order data conversion unit and a recording head control unit. It is a time chart of the signal which a read timing control part generates. It is a figure which shows the structure of SRAM918 for block order data storage. It is a figure which shows an example of the block drive order data written in the address 0 to the address 15 of the block drive order data memory 211. 2 is a diagram illustrating a configuration of a drive circuit provided in the recording head 11. FIG. It is a time chart which shows the drive timing by a block enable signal. It is a figure explaining inclination shift. It is a figure explaining inclination shift.

  Hereinafter, preferred embodiments of the present invention will be described more specifically and in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the already demonstrated part and duplication description is abbreviate | omitted.

  In this specification, “recording” (sometimes referred to as “printing”) is not limited to the case of forming significant information such as characters and graphics, but may be significant. Furthermore, it also represents 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 whether or not it is manifested so that a human 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.

  Further, “ink” (sometimes referred to as “liquid”) should be interpreted widely as in the definition of “recording (printing)”. Therefore, by being applied on the recording medium, it is used for formation of images, patterns, patterns, etc., processing of the recording medium, or ink processing (for example, solidification or insolubilization of the colorant in the ink applied to the recording medium). It shall represent a liquid that can be made.

  Furthermore, unless otherwise specified, the “recording element” collectively refers to an ejection port or a liquid path communicating with the ejection port and an element that generates energy used for ink ejection.

<Description of Inkjet Recording Apparatus (FIG. 1)>
FIG. 1 is an external perspective view showing an outline of the configuration of an ink jet recording apparatus which is a typical embodiment of the present invention. An ink jet recording apparatus (hereinafter referred to as a 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 that is supported by a carriage shaft 104 so as to be movable in the main scanning direction of an arrow X, and a 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.

<Description of recording head (FIG. 2)>
FIG. 2 is a diagram illustrating the nozzle configuration of the recording head. FIG. 2A shows the arrangement of the ink discharge ports 13 on the ink discharge port surface of the recording head 11. The ink discharge port arrays 141, 142, 143, and 144, in which a plurality of ink discharge ports 13 are arranged to form a printing element array, are formed by arranging 128 ink discharge ports 13 respectively, and black, cyan, magenta, and yellow inks. Discharge drops.

  In the present invention, the configuration of the recording head 11 is not characteristic. For example, the ink discharge port arrays 141, 142, 143, and 144 of each color are from two columns in which the ink discharge ports 13 are alternately arranged in the sub-scanning direction. The structure which consists of may be sufficient. Further, the number of the ink ejection ports 13 in the black ink ejection port array 141 may be larger than the number of the ink ejection ports 13 in the other color ink ejection port arrays 142, 143, and 144.

  In the description of this embodiment, the following description will be given focusing on one ink discharge port array (black ink discharge port array 141). The same applies to the other ink discharge port arrays 142, 143, and 144. Inclination deviation correction can be performed.

  FIG. 2B shows an ink ejection surface of the recording head 11 having an ink ejection port array 141 composed of 128 ink ejection ports 13. In FIG. 6A, the upper side of the ink discharge port array 141 corresponds to the upstream side in the sub-scanning direction. The 128 ink discharge ports 13 are set as ink discharge ports of nozzle numbers 0 to 127 in order from the upstream side in the sub-scanning direction toward the downstream side. Further, 16 ink discharge ports 13 that are adjacent to each other from the smaller nozzle number are divided into groups 0 to 7, and the recording elements corresponding to the ink discharge ports having the smaller nozzle numbers in each group are sequentially ordered from block 0 to block 0. 15 is assigned. 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 (time-division driving). In the description of the present embodiment, dots are formed in an area corresponding to three columns from the position of the first column to the position of the third column of the recording medium using all the ink ejection ports 13 of the recording head 11. The case where an image is recorded will be described as an example.

<Creation of test pattern (FIGS. 3 to 4)>
Next, an outline of tilt deviation correction in the ink jet recording apparatus of this embodiment will be described. The ink jet recording apparatus of the present embodiment is characterized in that it corrects the tilt deviation of dots. Although any method may be used to detect the information on the inclination deviation (inclination information), an example in which information on the inclination deviation is acquired using an optical sensor will be described.

  FIG. 3 is a flowchart showing an outline of dot inclination shift value detection.

  First, in step S110, a test pattern is created. The test pattern is created by recording a plurality of test patches on a recording medium at different ejection timings. Next, in step S120, the optical characteristics of each test patch are measured using an optical sensor, and information on tilt deviation is detected. In this embodiment, the reflection optical density of the test patch is measured as an optical characteristic measurement. In step S130, correction information is determined from information regarding the detected tilt deviation, and is set in a correction amount memory (first memory) 205 (described later).

  Next, the creation of the test pattern in step S110 and the detection of information relating to the tilt deviation by the optical characteristic measurement in step S120 will be described. Here, the amount of deviation of the dots formed by the three ink ejection ports 13 on the upstream side and the downstream side in the sub-scanning direction, which are both ends of the ink ejection port array 141, is detected as the information about the tilt deviation with respect to the main scanning direction. To do.

  FIG. 4 shows a test pattern formed on the recording medium 12 in step S110, and the test pattern includes seven test patches 401 to 407. Each test patch is formed as follows. First, using the three upstream ink discharge ports 13 in the sub-scanning direction, a plurality of images composed of dots for four consecutive columns are recorded with an interval of four columns. Next, the recording medium 12 is conveyed, and an image composed of dots for four consecutive columns is recorded using three downstream ink ejection openings at intervals of the four columns. Here, ink is ejected from three ink ejection ports on the upstream and downstream sides in the sub-scanning direction of the recording head, and recording is performed while moving the recording head from left to right in FIG. (One-way recording).

  With respect to the test patch 404, the test patch is formed by ejecting ink from the three downstream ink ejection ports at the timing assumed to just fill the interval of the four columns. On the other hand, for the test patches 405, 406, and 407, the drive timing of the downstream ink discharge ports 13 is delayed, and the images from the downstream ink discharge ports are respectively shifted in the right direction in FIG. It is created so as to be shifted by 1/2 pixel, 1 pixel, and 3/2 pixels. For the test patches 403, 402, 401, the drive timing of the downstream ink ejection port 13 is advanced, and the images from the downstream ink ejection ports are each 1 in the left direction in the figure from the interval of the four columns. / 2 pixels, 1 pixel, 3/2 pixels so as to be shifted.

<Detection of inclination (deviation) using test pattern (FIGS. 5 to 7)>
A method for detecting a deviation amount in the main scanning direction of dots formed from the three ink ejection ports 13 on the upstream side and the downstream side from the created test pattern will be described. FIGS. 5A and 5B are diagrams showing an image 408 of the test patch 404 when there is a tilt shift and a dot arrangement at that time. In the image 408 of the test patch 404, a dot overlapped portion and a dotless portion, which become a black stripe 409 and a white stripe 410 according to the inclination shift, are generated. When there is a tilt shift, as shown in FIG. 6, there is a shift L in the main scanning direction between the upstream dot 411 in the sub-scanning direction and the downstream dot 412 in the sub-scanning direction. The test patch 404 records an image from the downstream ink discharge port 13 at a timing assumed to just fill the interval of the four columns when an image is recorded at the upstream ink discharge port 13. Therefore, as shown in the overlapping portion 413 and the blank portion 414 in FIG. 5B, an overlapping portion or a blank portion due to the upstream side dot 411 and the downstream side dot 412 is generated, and FIG. An image 408 having such black stripes 409 and white stripes 410 is obtained. In this way, it is possible to detect the occurrence of a tilt deviation from the image 408 of the test patch 404.

  The detection of the shift amount in the main scanning direction when there is such a tilt shift will be described. In this description, it is assumed that among the seven test patches, the test patch 406 is an image 415 having a uniform recording density without black lines and white lines as shown in FIG. FIG. 7B shows details of the dot arrangement of the image 415.

  The test patch 406 forms a downstream dot 412 by delaying the drive timing of the downstream ink ejection port and shifting one pixel in the main scanning direction from the interval of the four columns. Therefore, if there is no tilt deviation, black stripes and white stripes should appear at intervals of the four columns. However, since a deviation L in the main scanning direction between the upstream dot 411 and the downstream dot 412 as shown in FIG. 6 has occurred, when this deviation delays the drive timing of the downstream ink ejection port 13. The misalignment that should be possible is offset. Therefore, the test patch 406 is an image 415 having a uniform recording density. In this way, it is possible to detect that a tilt deviation in the clockwise direction in which the dot deviation amount in the main scanning direction between the upstream dot 411 and the downstream dot 412 is one pixel has occurred.

  In this way, by selecting an image with a uniform recording density from the test patches created by varying the drive timing of the downstream ink discharge ports, dot displacement in the main scanning direction as information regarding inclination displacement is selected. The amount can be detected.

  In step S120, the reflected optical density of these seven test patches is measured using an optical sensor. By selecting a test patch having a high reflection optical density from this measurement result, it is possible to detect a test patch having no black stripes and white stripes and a uniform dot arrangement.

  Hereinafter, when the test patch 406 is detected as a uniform image, that is, in a clockwise direction in which dots formed by the upstream recording element and the downstream recording element are shifted by one pixel in the main scanning direction. A description will be given of a method for correcting inclination deviation in the case where inclination deviation occurs.

<Correction of tilt (deviation) (FIGS. 8 to 10)>
FIG. 8 shows correction value information (tilt information) held in the correction amount memory (first memory) 205, and information on how many recording timing signals are corrected during 16-division driving ( Tilt correction amount) is held. That is, the correction amount memory (first memory) 205 holds information (correction information) related to the tilt corresponding to the group. In this example, the set value 0 is set so that no correction is performed for the group 0. Group 1 has a setting value 2 for correcting two recording timing signals, group 2 has a setting value 4 for correcting four recording timings, and group 3 has six recording timings. The set value 6 is set to correct the above. Set values 8, 10, 12, and 14 are set for group 4, group 5, group 6, and group 7, respectively.

  In the present embodiment, the correction value 0 is set based on the group 0, but the reference group may be any group. For example, with group 7 as a reference, setting value 2 for group 6, setting value 4 for group 5, group 4, group 3, group 2, group 1, group 0 for setting value 6, Settings such as 8, 10, 12, and 14 are made. In contrast to the correction based on the group 0, the recording timing signal may be corrected so as to be advanced in accordance with the number of set values.

  FIG. 9A shows the nozzle numbers, selection blocks, and print data assigned to the print elements of group 0 to group 7. FIG. 9B is a diagram showing the arrangement of dots recorded on the recording medium corresponding to FIG. This recording data indicates data at the time when it is transferred to the recording head. FIG. 9A is based on the premise that there is no inclination of the nozzle row in order to make the explanation of correction easy to understand. “◯” indicates dots recorded by the recording data. The recording data in FIG. 9 is based on the recording data stored in the transfer buffer 213 (described later), and is selected according to the inclination and transferred to the recording head. The dot arrangement schematically shows dots formed on the recording medium when recording is performed based on the recording data stored in the transfer buffer 213 when there is no tilt deviation.

  In FIG. 9, the recording positions corresponding to the number specified by the correction information are shifted from the recording elements whose ejection order is early in each group. This point will be described with reference to FIG. For example, the correction information value of group 0 is 0. Accordingly, in the dot arrangement corresponding to the nozzles belonging to group 0, all dots are described in the first column, and further, dots are arranged in the first to third columns. The correction information value of group 1 is 2. Accordingly, in the dot arrangement corresponding to the nozzles belonging to the group 1, the positions corresponding to the nozzle number 16 (selected block 0) and the nozzle number 17 (selected block 1) are blank. It is from nozzle number 18 that the dot is described. In the fourth column, dots are written at positions corresponding to nozzle number 16 and nozzle number 17. The correction information value of group 2 is 4. Accordingly, in the dot arrangement corresponding to the nozzles belonging to the group 2, the positions corresponding to the nozzle numbers 32 to 35 are blank. It is from nozzle number 36 that a dot is described. In the fourth column, dots are written at positions corresponding to the nozzle numbers 32 to 35. As described above, the recording timing is delayed by the correction information.

  FIG. 10 shows the arrangement of dots formed on the recording medium by the tilt deviation correction of this embodiment. White dots in the figure indicate dots formed when the tilt deviation correction of the present embodiment is not performed.

  When an inclination shift occurs, dots are formed at positions outside the column area that should be originally arranged, but the number of dots varies from group to group. In the description of the present embodiment, the number of dots formed at positions out of the inclination shift is 0 for group 0, 2 for group 1, 4 for group 2, and 6 for group 3 on the basis of group 0. It increases in order.

  Therefore, in the tilt deviation correction of the present embodiment, the recording data assigned to the corresponding recording element is changed for the dots formed at a position outside the column region that should be originally arranged. Specifically, when generating the recording data assigned to the corresponding recording element, the storage position of the image data assigned to the recording element can be changed in the main scanning direction of the recording head for each recording element. With this configuration, even if the number of dots formed at a position outside the column area to be originally arranged differs for each group, the storage position of the image data assigned to the corresponding recording element for the dot at the outside position is different. Can be changed.

  In this way, when there are dots arranged in the column area that should originally be arranged in the group and dots arranged outside the area, the dots outside the area are arranged. Are offset in the main scanning direction. In this way, it can correct | amend so that it may fit in the area | region of the same column.

<Circuit Configuration for Performing Inclination (Displacement) Correction (FIGS. 11 to 21)>
Here, the configuration of a control circuit provided in the ink jet recording apparatus 1 for executing tilt deviation correction will be described.

  FIG. 11 is a block diagram illustrating a control configuration of the recording apparatus. As shown in FIG. 11, the raster unit image data received from the host (PC) 901 is received by the interface 903 of the ASIC 902 and stored in the reception buffer 905 of the SRAM 904. The image data stored in the reception buffer 905 is compressed to reduce the amount of data transferred from the host (PC) 901. Therefore, the reception data control unit 906 reads the compressed data, the recording data expansion unit 907 executes compression expansion and data rearrangement, and stores the expanded data in the recording buffer 908 as recording data.

  FIG. 12 is a diagram schematically showing recording data stored in the recording buffer.

  As shown in FIG. 12A, the storage addresses of the recording data in the recording buffer 908 are addresses N + 000h to N + 0FEh in the column direction corresponding to 128 recording elements constituting the recording head 11. Yes. Here, h indicates that the address is in hexadecimal notation. In the raster direction, there is a memory area corresponding to recording resolution × size of the recording medium. Here, when the recording resolution is 1200 dpi and the size of the recording medium in the raster direction (main scanning direction, which is the moving direction of the recording head) is 8 inches, the memory area can store 9600 dots of image data.

  FIG. 12B shows a detailed configuration of addresses N + 000h to N + 01eh of the recording buffer 908. Each address corresponds to the nozzle number of the recording head 11. Accordingly, the N + 0h address holds the recording data of the nozzle number 0, and the N + 2h address holds the recording data of the nozzle number 1. In addition, bit 0 of each address holds the record data of column 0, bit 1 holds the record data of column 1, and the record buffer holds the record data to be recorded in the next column in the bit raster direction. It has a configuration. As described above, the print data of the same nozzle number is held in the address of the print buffer 908.

  However, actually, the record data of bit 0 from address 000h to 0FEh is recorded as the first column, and then the record data of bit 1 from address 000h to 0FEh is recorded as the second column. Must be sorted in the order of recording. Therefore, the HV conversion unit 909 performs HV conversion on the recording data stored in the raster direction in the recording buffer 908, and records the data in the column data storage SRAM (third memory) 912 in the recording order, that is, in the column direction. Store data.

  FIG. 13 is a diagram for explaining the operation of HV conversion. The HV conversion is performed in units of 16 × 16 bits, and the data of bit 0 from the address N + 0h to N + 1Eh read from the recording buffer 908 is written to the address M + 0h of the column data storage SRAM 912. This operation is repeated 16 times. HV conversion is performed in groups of 16 nozzles, and is performed in order from group 0 to group 7.

  Next, the operation of the recording timing generation unit 911 that generates the recording data signal and the recording timing will be described with reference to a signal time chart shown in FIG.

  The recording timing generation unit 911 receives an encoder signal ENC generated from an optical linear encoder (not shown) for detecting a recording position in the recording head movement direction (main scanning direction) of the recording apparatus. Based on the encoder signal ENC, a column data generation section signal, a block data generation section signal, a recording section signal, a head trigger signal, and a head heat trigger signal are generated.

  The head trigger signal generates a trigger in units of one column, and the head heat trigger signal generates a trigger in units of recording, that is, block drive units. Since the recording head 11 of this embodiment is time-distributed by 16 blocks, 16 head heat trigger signals are generated in one column. The column data generation interval signal is input to the HV conversion unit 909, and the HV conversion unit 909 performs HV conversion in units of 16 columns by counting the number of column data generation interval signals and head trigger signals. The block order data conversion unit 913 counts the number of block data generation interval signals and head heat trigger signals, and performs data conversion in units of one column. The recording head controller 919 transfers the block data to the recording head 11 for each head heat trigger signal in the recording section signal, and performs recording control.

  FIG. 15 is a diagram showing the configuration of the SRAM 912 for storing column data. As can be seen from FIG. 15, the SRAM 912 includes 33 columns of memory area for each group of nozzles. Since the HV conversion by the HV conversion unit 909 is performed during the recording operation and needs to be processed at high speed, the memory configuration is such that the writing operation and the reading operation to the SRAM 912 can be performed simultaneously. . In the HV conversion, since conversion is performed in units of 16 columns as described above, memory for 16 columns is required for writing, memory for 16 columns is required for reading, and memory for 32 columns is required in total. It is. In addition, since the column data immediately before the currently driven column is used in the inclination shift correction, a memory of one column or more is required. Therefore, in this embodiment, a description will be given of a configuration in which memory for one column, which is the minimum configuration, is used for tilt deviation correction, and a configuration for storing data for 33 columns. However, a configuration with more columns than that may be used. Absent.

  Next, a detailed description will be given of the configuration and processing of a circuit that executes tilt deviation correction in the present embodiment.

  FIG. 16 is a block diagram showing detailed configurations of the block order data conversion unit and the printhead control unit. These two control circuits mainly execute the inclination correction processing in this embodiment.

  When the read timing control unit 201 receives the block data generation section signal from the recording timing generation unit 911, the read timing control unit 201 generates a read timing signal to the column data reading unit 202. As shown in FIG. 17, the read timing signal is a block data generation logic that is a logical sum of a block data generation signal 501 from the recording timing generation unit 911 and a block data generation shift signal 502 obtained by delaying the input signal by one column. The sum signal 503 is obtained. Thus, the reason why the read signal is input to the column data read unit 202 as the logical sum of these two signals is as follows. That is, in the tilt deviation correction in this embodiment, since the recording data is shifted by a maximum of one column (16 blocks in terms of block driving unit), the read signal is extended to generate the shifted data. Because it is necessary to do.

  When the column data read unit 202 receives the read signal, the column data read unit 202 starts reading column data from the SRAM 912 based on the information from the column number management unit 203. The number-of-columns management unit 203 manages the current read column numbers such as 0, 1, 2,..., 32, 33, 0, 1, 2,. In response to a read completion signal from the column data reading unit 202, the read column number is counted up. The column data read by the column data reading unit 202 is data of the current read column number indicated by the column number management unit 203 and the previous read column number. The read column data is subjected to inclination deviation correction in the data selection unit 206, and the data obtained as a result is held in the column data holding unit 207.

  The data selection unit 206 reads out the block data generation signal 501 from the recording timing generation unit 911 shown in FIG. 17 and the block data generation shift signal 502 obtained by delaying the input signal by one column in order to correct the tilt deviation. Received from the timing control unit 201. Then, it is determined whether the current read data is the data of the first column, the data of the last column (the fourth column in this embodiment), or other data. That is, in the case of the first column data, the previous column read data output from the column data reading unit 202 is replaced with “0” (or discarded), and in the case of the last column data, the currently read column data Is replaced with “0” (or discarded). In the other columns, tilt deviation correction data is generated using the two read column data.

  This generation is executed based on the comparison result by comparing information in the block drive order memory (second memory) 204 and the correction amount memory (first memory) 205. That is, when the correction amount from the correction amount memory (first memory) 205 is CORR and the block number from the block drive order memory (second memory) 204 is BLKn, if CORR ≦ BLKn, Select the data for the read column. On the other hand, if CORR> BLKn, data of the previous read column is selected, data for one column is generated, and then output to the column data holding unit 207.

  Here, the inclination deviation correction will be described with a specific example. As shown with reference to FIG. 8, here, group 0 is recorded with a set value of 0 and no correction is performed, group 1 is recorded with a set value of 2 and two recording timing signals are corrected, and group 2 is recorded with a set value of 4. Correction for four timings, and correction for six recording timings with a set value 6 for group 3 are performed. Further, group 4, group 5, group 6, and group 7 are set to 8, 10, 12, and 14, respectively, and recording control of 1 to 4 columns is performed.

  That is, when generating the data of the first column, the data of the column 0 and the column 32 which is the previous column are read from the SRAM 912. Since the correction amount is 0 in group 0, column 0, which is the current column, is selected as the data for all blocks. Since the correction amount in group 1 is 2, blocks 0 and 1 are the data in column 32, which is the previous column (in the first column, the previous column data is converted to 0 and corrected in the tilt deviation correction). Block 2-15 selects the data in column 0. The same control is performed for the groups 2 to 7 to correct the tilt deviation of the first column.

  For the second and third columns, the current column and the previous column data are read from the SRAM 912, the correction amount and the block drive order are compared from the two column data, and data is selected for each bit. In the fourth column, which is the last column, the data of column 3 that is the current column and the data of column 2 that is the previous column are read from the SRAM 912, the current column data is converted to 0, and data is selected according to the above procedure. I do. In this way, recording data subjected to tilt deviation correction is generated.

  Then, the column data held by the column data holding unit 207 is converted into block drive data by the block order data conversion unit 208 and written to the SRAM 918 for storing block order data. The SRAM 918 has a two-bank configuration in which data for 16 blocks is one bank as shown in FIG. 18 so that the write operation and the read operation are exclusive operations. When bank 0 is written, reading is performed from bank 1, and when bank 1 is written, reading is performed from bank 0.

  The transfer count management unit 212 is a counter circuit that counts the number of block driving times of the recording signal, and is incremented every time the block data reading unit 210 reads data. In this embodiment, since the number of block driving operations per recording operation of the recording head 11 is 16, the transfer number management unit 212 repeats the control of counting from 0 to 15 and returning to 0. The transfer count management unit 212 counts the bank value of the SRAM 918, and performs control to switch the bank when the transfer count counter circuit counts 16 times.

  In the block drive order memory 211, 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 →. In this embodiment, the drive order is read from the block drive order memory 211 based on the transfer count counted by the transfer count management unit 212. In forward recording, addresses 0 → 1 → 2 →..., Reverse direction In recording, reading is performed in the order of addresses 15 → 14 → 13 →.

  The block data reading unit 210 reads the recording data from the SRAM 918 based on the timing signal from the drive timing control unit 209, the block number information from the block drive order memory 211, and the bank information. The block data holding unit 213 holds the recorded data. The held recording data is transferred to the recording head 11 by the recording data transfer unit 214 in synchronization with the data transfer clock signal generated by the data transfer clock generation unit 215.

  FIG. 19 shows an example of block drive order data written in addresses 0 to 15 of the block drive order data memory 211. In FIG. 19, block data indicating block 0 and block 1 are stored at address 0 and address 1 of the block drive order data memory 211, respectively. Similarly, block data indicating blocks 2 to 15 are sequentially stored at addresses 2 to 15.

  In this way, the recording data transfer unit 214 reads the block data set at addresses 0 to 15 in the block drive order data memory 211. Then, image data corresponding to each block data is read from the SRAM 912 for storing block order data and transferred to the recording head 11 to perform recording for one column.

  FIG. 20 shows a drive circuit provided in the recording head 11. The drive circuit divides and drives 128 printing elements 114 into 16 blocks, and drives 8 printing elements assigned to the same block. Data and signals to the drive circuit are sent from the recording data transfer unit 214 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 4-bit block enable signal 310, 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. 21 is a time chart 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 211. Therefore, as shown by the block enable signal 310 in FIG. 21, the divided block selection circuit sequentially designates the 16 blocks from the block 0 to the block 15 as the block drive order generated by the block drive order data memory 211. 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.

  Therefore, according to the embodiment described above, with respect to dots formed at positions deviating from the region of the column to be originally arranged, when the image data assigned to the corresponding recording element is generated, the recording data of the current column and one column are generated. It is possible to select from the two recording data of the previous recording data. In this way, tilt correction can be realized, and as a result, deterioration of image quality can be suppressed.

  Note that the data reading method may be such that data for two columns is always read and the data for one column is discarded in the first column and the last column. Further, only the recording data of the current column is read in the first column, and only the recording data of the previous column is read out in the fourth column, so that only the recording data for one column is read out in the first column and the last column. It may be a configuration.

Claims (5)

A recording apparatus that performs recording by scanning a recording head having a recording element array in which a plurality of recording elements are arranged based on image data,
A recording buffer for storing recording data used for recording by scanning of the recording head;
A drive unit configured to form a group of a predetermined number of recording elements so that adjacent recording elements are included in different blocks among the plurality of recording elements, and performing time-division driving for each block;
A first memory that holds tilt information corresponding to a group in the scanning direction of the recording head of the recording element array;
A second memory for storing a block number indicating a block driving order for the time-division driving;
A third memory for storing, as column data, recording data for a plurality of columns among the image data stored in the recording buffer;
Based on the inclination information held in the first memory and the block number stored in the second memory, column data for two consecutive columns is read from the third memory, and the read column Generation means for selecting column data of any column corresponding to recording elements driven in time division by the driving means among the data, and generating a recording data signal used for recording by the recording head;
A recording apparatus comprising: a transfer means for transferring the recording data signal generated by the generating means to a recording head.   The recording apparatus according to claim 1, further comprising a reception buffer for storing image data received from the host.   The recording apparatus according to claim 1, wherein the tilt information is held for each group. The generating means includes
A comparing means for comparing the inclination information with the block number;
4. The apparatus according to claim 1, further comprising a selection unit that selects any one of the column data for the two consecutive columns based on a result of the comparison performed by the comparison unit. Recording device. A recording head having a recording element array in which a plurality of recording elements are arranged and having a predetermined number of recording elements so that adjacent recording elements are included in different blocks with respect to the plurality of recording elements is scanned. A method for controlling a recording apparatus that performs time-division driving for each block while performing recording based on image data,
Holding the tilt information corresponding to the group in the first memory in the scanning direction of the recording head of the recording element array;
Storing a block number indicating a block driving order for the time-division driving in a second memory;
Storing recording data used in recording by scanning of the recording head in a recording buffer;
Of the image data stored in the recording buffer, storing a plurality of columns of recording data as column data in a third memory;
Based on the inclination information held in the first memory and the block number stored in the second memory, column data for two consecutive columns is read from the third memory, and the read column A step of selecting column data of any column corresponding to the time-division driven recording element, and generating a recording data signal used for recording by the recording head;
Transferring the generated recording data signal to the recording head;
And a step of time-division driving the recording head for each block based on the transferred recording data signal.