JP2014091304A - Ink jet recorder, and correction method of recording position deviation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly correct a recording position deviation between chips or a recording position deviation between recording heads in an ink jet recorder of a full line type, which is constituted by arraying a plurality of chips having a plurality of nozzle rows.SOLUTION: Provided is an ink jet recorder for recording an image by using a recording head at which a plurality of chips are arranged having a plurality of nozzle rows in which nozzles discharging ink are disposed, in a direction orthogonal to an arrangement direction of the nozzle rows. The ink jet recorder includes: means for recording a pattern for detecting a recording position deviation between the chips for each nozzle row; means for reading the recorded pattern; means for analyzing a reading result of the pattern; and means for obtaining a respective amount of recording position deviation between the chips for each nozzle row, from the analysis result of the pattern, in order to determine a correction value for correcting the recording position deviation between the chips.

Description

  The present invention relates to an ink jet recording apparatus and a recording position shift correction method. In particular, the present invention relates to a method for correcting a recording position shift of an ink jet recording apparatus that records a plurality of nozzle arrays extending in the width direction of a sheet in parallel and records an image on the sheet.

  The full-line type ink jet recording apparatus includes a full-line head in which nozzles are arranged over the entire width direction of the paper, and images are recorded on the paper by conveying the paper to the full-line head. When a plurality of inks such as color image output are used, the full line head is further arranged in parallel in the paper transport direction.

  In such a full-line type ink jet recording apparatus, a recording position shift due to an attachment error between full-line heads may occur. In Patent Document 1, in order to correct the recording position deviation between a plurality of recording heads, the recording position deviation between the recording heads is recorded in two stages of coarse adjustment and fine adjustment while recording a test pattern unrelated to the image. A method of correcting is disclosed.

  On the other hand, in order to improve the manufacturing yield, the full line head is often configured by arranging a plurality of small chips in which a plurality of nozzles are arranged. In this case, in each individual full line head, a recording position shift may occur between chips, and it is necessary to correct the recording position shift between chips.

  In recent years, there has also been provided a printing apparatus that includes a plurality of nozzle arrays that eject the same ink on a single chip, and that is intended to achieve higher speed and higher resolution.

JP 2004-181697 A

  However, in a chip in which a large number of nozzles are arranged at a high density, an air flow may be generated during ejection, resulting in a recording position shift. According to the study by the present inventors, when there are a plurality of such nozzle rows on the same chip, it was confirmed that the amount of the recording position deviation differs depending on the position of the nozzle row.

  In this case, even if the recording position deviation between the chips and the recording position deviation between the recording heads are corrected using only one nozzle row of each chip, a situation occurs in which the recording position deviation is not corrected in the other nozzle rows. However, in the past, the recording position deviation between the chips and the recording position deviation between the recording heads were not acquired after considering all the nozzle rows of all the chips. It was not possible to correct appropriately.

  The present invention has been made to solve the above problems. Therefore, the purpose is to appropriately correct the recording position deviation between chips and the recording position deviation between recording heads in a full-line type ink jet recording apparatus configured by arranging a plurality of chips having a plurality of nozzle rows. It is to be.

  In order to solve the above problems, an inkjet recording apparatus according to the present invention is a recording in which a plurality of chips each having a plurality of nozzle rows in which nozzles for ejecting ink are arranged in a direction intersecting the arrangement direction of the nozzle rows are arranged. An ink jet recording apparatus for recording an image using a head, wherein a unit for recording a pattern for detecting a shift in a recording position between the chips for each nozzle row, and a unit for reading the recorded pattern A means for analyzing the reading result of the pattern, and a correction for correcting the deviation of the recording position between the chips by obtaining the amount of deviation of the recording position between the chips for each nozzle array from the analysis result of the pattern. Means for determining a value.

  According to the above configuration, by obtaining the recording position deviation amount between the chips for each nozzle row, it is possible to appropriately correct the recording position deviation between the chips and the recording position deviation between the recording heads.

It is sectional drawing which shows the internal structure of an inkjet recording device. It is sectional drawing which shows the internal structure of the recording device for demonstrating the operation | movement at the time of single-sided recording. It is sectional drawing which shows the internal structure of the recording device for demonstrating the operation | movement at the time of double-sided recording. It is a schematic diagram which shows a recording head. It is a block diagram which shows a control part. (A)-(c) is a schematic diagram which shows a pattern. It is a schematic diagram which shows a tile pattern. It is a schematic diagram for demonstrating the analysis method of a tile pattern. It is a schematic diagram for demonstrating the analysis method of a tile pattern. It is a schematic diagram which shows the overlap area | region of a chip | tip. It is a schematic diagram for demonstrating the correction method. It is a schematic diagram for demonstrating the correction method. (A) And (b) is a schematic diagram which shows the pattern of 2nd Embodiment.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view showing the internal configuration of the inkjet recording apparatus 20. As shown in the figure, the ink jet recording apparatus 20 (hereinafter referred to as “recording apparatus 20”) is connected to an external device 16. The external device 16 supplies image data to the recording device 20. In the present embodiment, the recording device 20 records an image on a roll-shaped recording medium based on the image data received from the external device 16.

  The recording device 20 includes a supply unit 1, a decurling unit 2, a skew correction unit 3, a recording unit 4, an inspection unit 5, a cutting unit 6, an information recording unit 7, a drying unit 8, a winding unit 9, a discharge conveying unit 10, A sorter unit 11, a discharge tray 12, and a control unit 13 are provided. The control unit 13 includes a controller unit 15 and a power supply unit (not shown). The control unit 13 controls each unit in the recording apparatus 20. The controller unit 15 receives image data from the external device 16. The power supply unit supplies a voltage to each component in the recording apparatus 20.

  The recording apparatus 20 is provided with a conveyance mechanism having a plurality of roller pairs 17 and a belt, and the recording medium is conveyed along the conveyance path 18 by the conveyance mechanism.

  The supply unit 1 accommodates a roll-shaped recording medium wound around the roll R1 and the roll R2, pulls out the recording medium from the roll R1 or the roll R2, and supplies the recording medium to the decurling unit 2. In the present embodiment, the supply unit 1 accommodates two rolls, that is, a roll R1 and a roll R2, but the number of rolls to be accommodated is not limited to this, and may be one, or two or more. There may be.

  The decurling unit 2 reduces curling (warping) of the recording medium supplied from the supply unit 1. The skew correction unit 3 corrects the skew (tilt with respect to the original traveling direction) of the recording medium that has passed through the decurling unit 2. The recording medium whose skew has been corrected by the skew correction unit 3 is conveyed to the recording unit 4.

  The recording unit 4 forms an image on a recording medium and performs recording. Further, in the present embodiment, the recording unit 4 records a pattern for detecting a recording position shift described later with reference to FIG. 6 and the like, a cut mark pattern for confirming a cutting position of the recording medium, and the like. The recording unit 4 is provided with a plurality of inkjet recording heads 14 (hereinafter referred to as “recording heads 14”). Each recording head 14 is a full-line type recording head, and has a length corresponding to the width of the recording medium of the maximum size expected to be used.

  The inspection unit 5 has a scanner, and the scanner records images and various patterns recorded by the recording unit 4. The inspection unit 5 includes a CPU (not shown) for analyzing the reading result. The inspection unit 5 analyzes the read information by the CPU to determine the ejection state of the nozzles of the recording head, the conveyance state of the recording medium, the recording position, and the like.

  The scanner includes a light emitting unit (not shown) and an image sensor. The light emitting unit is disposed at a position that emits light toward the reading direction of the image sensor, or at a position that emits light toward the image sensor with a recording medium interposed between the light emitting unit and the image sensor. In the former case, the imaging element receives reflected light of the light emitted from the light emitting unit, and in the latter case, the imaging element receives light transmitted through the recording medium out of the light emitted from the light emitting unit. The image sensor converts the received light into an electrical signal and outputs the electrical signal.

  In the present embodiment, a Charge Coupled Devices (CCD) image sensor is used as the image sensor. In this embodiment, a case where a line sensor provided with a CCD sensor is used along a direction intersecting the conveyance direction of the recording medium (that is, the nozzle arrangement direction of the recording head 14) will be described. A sensor may be used.

  The cutting unit 6 cuts the recording medium on which the image is recorded by the recording unit 4 into a predetermined length. The information recording unit 7 records information such as a serial number and date on the recording medium cut to a predetermined length by the cutting unit 6 as necessary. The drying unit 8 heats the recording medium and dries the ink or the like applied to the recording medium. When performing double-sided recording on the recording medium, the winding unit 9 temporarily winds the recording medium on which recording has been completed on one side. The wound recording medium is conveyed again to the recording unit 4 so that ink is applied to a surface different from the surface on which recording is completed. Details of single-sided recording and double-sided recording will be described later.

  The discharge conveyance unit 10 conveys the recording medium dried by the drying unit 8 to the sorter unit 11. The sorter unit 11 discharges the recording medium to the discharge tray 12. The sorter unit 11 sorts the recording media as necessary, and sorts the recording media into different trays 12 and discharges them. The discharge tray 12 has a plurality of trays, and the recording medium sorted and discharged from the sorter unit 11 is placed on the tray.

  FIG. 2 is a cross-sectional view showing the internal configuration of the recording apparatus 20 for explaining the operation during single-sided recording. The recording medium 19 supplied from the supply unit 1 passes through the decurling unit 2 and the skew correction unit 3, and the recording unit 4 records an image on the surface facing the surface on which the nozzles of the recording head 14 are provided. . The recording medium 19 on which the image is recorded is cut into a predetermined length by the cutting unit 6 after passing through the inspection unit 5. Information is recorded on the back surface of the recording surface of the cut recording medium 19 by the information recording unit 7 as necessary. Then, the recording medium 19 is dried by the drying unit 8, and discharged to the discharge tray 12 through the discharge conveyance unit 10 and the sorter unit 11.

  FIG. 3 is a cross-sectional view showing the internal configuration of the recording apparatus 20 for explaining the operation during double-sided recording. The operation when the recording medium 19 is transported from the supply unit 1 to the inspection unit 5 is the same as that in the single-side recording described above. In the double-sided recording, the recording medium 19 is not cut by the cutting unit 6 until all the recording on the first recording side is completed.

  The recording medium 19 is conveyed to the drying unit 8 without recording information in the information recording unit 7. The recording medium 19 dried by the drying unit 8 is wound up by the winding drum of the winding unit 9. When all the recording on the first recording surface is completed, the recording medium 19 is cut by the cutting unit 6. All of the recording medium 19 on the downstream side in the conveyance direction of the recording medium from the cutting position is taken up by the winding unit 9, and the recording medium 19 on the upstream side in the conveyance direction from the cutting position is taken up by the supply unit 1.

  When the above operation is completed, the back side of the next recorded surface is recorded. The recording medium 19 is supplied to the decurling unit 2 by rotating the winding drum of the winding unit 9 in the direction opposite to the rotation direction at the time of winding.

  The recording medium 19 is supplied to the recording unit 4 through the decurling unit 2 and the skew correction unit 3, and an image is recorded on the back side of the first recorded surface by the recording unit 4. The recording medium 19 on which the image is recorded is conveyed to the cutting unit 6 through the inspection unit 5, and is cut into a predetermined length by the cutting unit 6. Since the recording medium 19 cut to a predetermined length is recorded on both sides, information is not recorded in the information recording unit 7 but is dried in the drying unit 8, and is ejected and transported unit 10 and sorter unit. 11 and then discharged to a discharge tray 12.

  In the present embodiment, the recording unit 4 uses four recording heads. An ink tank (not shown) is connected to each of the four recording heads so that the corresponding ink can be supplied. Corresponding ink is supplied from the ink tank to each recording head via an ink tube (not shown). In the present embodiment, the ink tank contains cyan (C), magenta (M), yellow (Y), and black (K) inks, respectively.

  FIG. 4 is a schematic diagram showing the configuration of the recording head 14. In the drawing, one of the four recording heads is shown, but the other three recording heads have the same configuration.

  In the present embodiment, a configuration including a recording head that supplies ink of four colors of K, C, M, and Y will be described. However, the type of ink color in the present invention is not limited to this. For example, a recording head that supplies ink such as light cyan ink, light magenta ink, red ink, and green ink may be provided. In this embodiment, the case where four recording heads are used will be described, but the number of recording heads is not limited to this.

  Each recording head is provided with a plurality of chips each having a plurality of nozzle rows in which nozzles are arranged in a direction crossing the recording medium conveyance direction (X direction shown in the drawing). The four recording heads are arranged in parallel so as to be substantially parallel to each other in the X direction.

  The recording head 14 includes electrode portions (not shown) at both ends in the nozzle array arrangement direction (Y direction shown in the drawing). This electrode part and the flexible wiring board (not shown) on the recording apparatus 20 side are electrically connected.

  As shown in FIG. 4, eight chips 101 to 108 are arranged on the recording head 14 in a staggered pattern so that the nozzles continue in the Y direction. The chips 101 to 108 are bonded and arranged on a base substrate 114 which is a support member in the recording head 14.

  In the chips 101 to 108, the nozzle rows A to G including a plurality of nozzles arranged in the Y direction cross the transport direction (the Y direction shown in the drawing), from the upstream side to the downstream side in the transport direction. They are arranged sequentially (in the X direction).

  The tips are arranged so that a predetermined number of nozzles overlap each other in the transport direction at the ends of the individual nozzle rows A to G in each tip.

  That is, the predetermined number of nozzles of the chip 105 and the predetermined number of nozzles of the chip 101 are the predetermined number of nozzles of the chip 101 and the predetermined number of nozzles of the chip 106 are the predetermined number of nozzles of the chip 106 and the predetermined number of chips 102. The nozzles are arranged so as to overlap each other.

  Similarly, the predetermined number of nozzles of the chip 102 and the predetermined number of nozzles of the chip 107 are the predetermined number of nozzles of the chip 107 and the predetermined number of nozzles of the chip 103 are the predetermined number of nozzles of the chip 103 and the predetermined number of chips 108. These nozzles are arranged so as to overlap each other. The predetermined number of nozzles of the chip 108 and the predetermined number of nozzles of the chip 104 are also arranged so as to overlap.

  A temperature sensor for measuring the temperature of the chip is attached to the chip (not shown). Each nozzle is provided with a drive element for ejecting ink according to the recording data.

  In the present embodiment, a heating resistor element (heater) is used as the drive element. The heat generating resistor element generates heat when energized, causes the liquid (ink) to foam by the generated heat, and discharges the liquid (ink) from the discharge port by the foaming energy. The ejected ink droplets are applied to the recording medium to form dots on the recording medium, and the dots form an image, thereby recording on the recording medium. As the driving element, a piezo element, an electrostatic element, a Micro-Electro-Mechanical Systems (MEMS) element, or the like can also be used. The voltage is supplied to each drive element from the power supply unit.

  Further, as shown in FIG. 4, the effective discharge width in the Y direction in the chips 101 to 108 is about 1 inch. Therefore, the recording head 14 in which the chips 101 to 108 are arranged in the Y direction has an effective ejection width of about 8 inches, and the length (width) of the A4 size recording medium in the short side direction is as follows. The length is almost the same.

  Therefore, when an A4 size recording medium is conveyed in the X direction in a portrait orientation, an image is completed by passing the paper once. In the present embodiment, the four recording heads 14 that respectively eject four colors of ink are the same liquid ejecting head, and these constitute a liquid ejecting recording apparatus capable of full color recording.

  FIG. 5 is a block diagram showing the concept of the control unit 13. The control unit 13 includes a controller unit 15 (range surrounded by a broken line), an image processing unit 207, an engine control unit 208, an individual unit control unit 209, and an operation unit 211.

  The controller unit 15 includes a CPU 201, ROM 202, RAM 203, HDD 204, and various I / O interfaces (I / F) 205.

  A CPU 201 (central processing unit) controls the operation of each unit of the printing apparatus in an integrated manner. The ROM 202 stores programs executed by the CPU 201 and fixed data necessary for various operations of the printing apparatus. A test pattern for correcting a recording position shift described later is also stored in the ROM 202.

  The RAM 203 is used as a work area for the CPU 201, used as a temporary storage area for various received data, and stores various setting data. The HDD 204 (hard disk) can store and read programs to be executed by the CPU 201, recording data, and setting information necessary for various operations of the recording apparatus 20.

  The interface 205 is an interface (I / F) for connecting the controller unit 15 to the external device 16 and is a local I / F or a network I / F.

  A dedicated processing unit is provided for units that require high-speed data processing. The image processing unit 207 performs image processing of recording data handled by the recording apparatus 20. The color space (for example, YCbCr) of the input image data is converted into a standard RGB color space (for example, sRGB). Various image processing such as resolution conversion, image analysis, and image correction is performed on the image data as necessary. The recording data obtained by these image processes is stored in the RAM 203 or HDD 204.

  The engine control unit 208 performs drive control of the recording head 14 of the recording unit 4 according to the recording data based on the control command received from the CPU 201 or the like. The engine control unit 208 further controls the transport mechanism of each unit in the recording apparatus 20.

  The individual unit control unit 209 includes a supply unit 1, a decurling unit 2, a skew correction unit 3, an inspection unit 5, a cutting unit 6, an information recording unit 7, a drying unit 8, a winding unit 9, a discharge conveyance unit 10, and a sorter unit. 11 is a sub-controller for controlling each unit of the discharge tray 12 individually. The individual unit control unit 209 controls the operation of each unit based on a command from the CPU 201. The above components are connected by the system bus 210.

  The operation unit 211 is an input / output interface with a user, and includes an input unit such as a hard key and a touch panel, and an output unit such as a display for presenting information and a sound generator.

  The external device 16 is a device that is a supply source of image data for causing the recording device 20 to perform recording. The external device 16 may be a general-purpose or dedicated computer, or may be a dedicated image device such as an image capture having an image reader unit, a digital camera, or a photo storage. When the external device 16 is a computer, an OS, application software for generating image data, and a printer driver for the printing apparatus are installed in a storage device included in the computer. Note that it is not essential to implement all of the above processing by software, and a part or all of the processing may be realized by hardware.

  6A to 6C are schematic diagrams showing patterns for correcting the recording position deviation. FIG. 4A shows a layout of a pattern for measuring misalignment of various recording positions, FIG. 4B is an enlarged view of the pattern 501 in FIG. 4A, and FIG. It is an enlarged view of the pattern 505 in (a). The alphabets in the white squares (squares in this embodiment) in FIGS. 4A to 4C correspond to the nozzle rows A to H shown in FIG. 4, and these squares constitute the corresponding nozzle rows. A pattern recorded by a nozzle is shown.

  6A shows the arrangement of the chips 101 to 108 in one recording head 14, and the lower part shows the arrangement of patterns to be recorded by the nozzles of the chips 101 to 108 in the four recording heads. It is shown.

  Patterns 501 to 504 are patterns for measuring the shift of the recording position between chips in each recording head. The patterns 501 to 504 are recorded by the nozzles of the chips 101 to 108 of the recording heads 14 (K) to (Y).

  The pattern 501 is the recording head 14 (K) that discharges black ink, the pattern 502 is the recording head 14 (C) that discharges cyan ink, and the pattern 503 is the recording head 14 (M) that discharges magenta ink. , The patterns to be recorded are shown. A pattern 504 indicates a pattern to be recorded by the recording head 14 (Y) that discharges yellow ink. A pattern 505 is a pattern for measuring the relative displacement of the recording position between the recording heads.

  FIG. 6B shows an enlarged view of the area recorded by the chips 104 and 108 in the pattern 501. In addition, in the same figure, although the structure of the pattern of the pattern 501 is demonstrated, the other patterns 502-504 are also the same structure.

  As shown in FIG. 5B, the pattern 501 is composed of a detection pattern 506, a reference pattern 507, and a tile pattern 508. The recording head 14 records the detection pattern 506, the reference pattern 507, and the tile pattern 508 in this order. For this reason, in the recording medium, the detection pattern 506, the reference pattern 507, and the tile pattern 508 are arranged in this order from the downstream side in the transport direction (X direction shown in the figure) as shown in FIG.

  The detection pattern 506 is a pattern for detecting which ink color (recording head) is used for recording. The ink color is analyzed by reading and analyzing the detection pattern 506 by the inspection unit 5. For example, if the R channel value is less than 10 in the RGB image, it is specified as a black ink pattern, and if it is 10 or more and 60 or less, it is specified as a cyan ink pattern. If the value of the G channel is 10 or more and 60 or less, the magenta ink pattern is specified. If the value of the B channel is 10 or more and 60 or less, the pattern is specified as yellow ink.

  The reference pattern 507 is used as a reference when detecting the tile pattern 508 recorded at a position separated from the reference pattern 507 by a predetermined pixel. The tile pattern 508 is used for pattern matching, and the shift amount of the recording position between chips is obtained from the tile pattern. Each of the tile patterns is the same dot pattern, and is recorded by any one of the nozzle arrays A to H in the same chip.

  In the present embodiment, 23 tile patterns are recorded by one chip. In the present embodiment, three patterns are recorded by the nozzles of the nozzle rows A to G, and two patterns are recorded by the nozzles of the nozzle row H.

  FIG. 6C is an enlarged view of the pattern 505. The pattern 505 is the same as the above-described pattern 501 except for the tile pattern configuration. That is, as shown in FIG. 5C, the pattern 505 is composed of a detection pattern 506, a reference pattern 507, and tile patterns 509 to 513. A detection pattern 506, a reference pattern 507, and a tile pattern are recorded in order from the downstream side in the transport direction. The detection pattern 506 may be recorded by any recording head as long as it can be seen that the pattern is a pattern for measuring the recording position deviation between the recording heads.

  Five tile patterns in the pattern 505 are recorded along the direction intersecting the conveyance direction of the recording medium. In order to obtain the displacement of the recording position between the recording heads, the tile patterns 509 to 513 are recorded by the nozzle row H of each recording head.

  That is, the tile pattern 509 is the recording head 14 (K), the tile pattern 510 is the recording head 14 (C), the tile pattern 511 is the recording head 14 (M), and the tile pattern 512 is the recording head 14 (Y). ) Shows patterns recorded respectively. Further, the tile pattern 513 is recorded by the nozzle array H of the recording head 14 (K) and in a region different from the region where the tile pattern 509 is recorded.

  As described above, the tile patterns 509 to 513 are recorded by the same nozzle row (nozzle row H in this embodiment) of the chip (chip 104 in this embodiment) arranged at the same position in each recording head. In the present embodiment, the case where the pattern 505 is recorded using only the chips 104 of the recording heads 14 (K) to (Y) has been described as an example. However, if the positions of the chips in the Y direction are aligned, each recording is performed. Recording may be performed using nozzles of other chips in the heads 14 (K) to (Y).

  FIG. 7 is a schematic diagram showing a tile pattern. As shown in the figure, the tile pattern is a pattern in which dots are randomly arranged. In the present embodiment, the tile pattern for obtaining the displacement of the recording position is randomly arranged. However, the tile pattern is not limited to this, and may be arranged regularly. Good. In this embodiment, since the recording position deviation is measured by pattern matching, the content and size are not limited as long as the same dot pattern is recorded in all patches so that pattern matching is possible.

  FIG. 8 is a schematic diagram for explaining the analysis method of the pattern 501 shown in FIGS. 6A and 6B, and is a diagram for explaining a method for obtaining the deviation amount of the recording position in one recording head. is there. In the figure, a method for obtaining the recording position deviation amount in the recording head 14 (K) will be described. However, the recording position deviation amounts in the other recording heads 14 (C, M, Y) can be obtained by the same method. it can.

  In FIG. 8, (1) displacement between nozzle rows in the recording medium conveyance direction (X direction shown in the drawing), (2) tip inclination, (3) displacement between chips in the X direction, and (4) X A method for analyzing the displacement between chips in the direction crossing the direction (Y direction shown in the figure) will be described.

  In the present embodiment, the amount of deviation of a desired item is calculated by performing pattern matching between tile patterns. Specifically, the vicinity of each pattern is read by a scanner, and the pixel position having the highest correlation with the template pattern shown in FIG. 7 stored in advance in a ROM or the like is detected. Then, various recording position shifts are acquired from the shift between the relative position of the pixel position of each pattern and the designed relative position. This will be described in detail below.

  In this embodiment, the shift amount of the recording position between the nozzle rows in the X direction is obtained from the shift of the printing position of the tile pattern recorded by the nozzle rows A to G with respect to the tile pattern recorded by the nozzle row H.

  In FIG. 8, tile patterns 701A, 702A, and 709A indicate patterns recorded by the nozzles of the nozzle array A, and tile patterns 701B, 703B, and 709B indicate patterns recorded by the nozzles of the nozzle array B, respectively. ing. Tile patterns 701C, 704C, and 709C indicate patterns recorded by the nozzles of the nozzle array C, and tile patterns 701D, 705D, and 709D indicate patterns recorded by the nozzles of the nozzle array D, respectively.

  Similarly, tile patterns 701E, 706E, and 709E indicate patterns recorded by the nozzles in the nozzle array E, and tile patterns 701F, 707F, and 709F indicate patterns recorded by the nozzles in the nozzle array F, respectively. Yes. Tile patterns 701G, 708G, and 709G indicate patterns recorded by the nozzles of the nozzle row G. Similarly, tile patterns 701H and 709H indicate patterns recorded by the nozzles of the nozzle row H.

  The tile patterns 701 to 709 (A to H) are patterns recorded by the nozzle rows (A to H) in the chip 104, and the tile patterns 710A to 710H are the nozzle rows (A to H) of the adjacent chips 108. H) is a pattern recorded. The area for recording the tile patterns 710A to 710H on the chip 108 and the area for recording the tile patterns 709A to 709H on the chip 104 are all included in the overlapping area indicated by the oblique lines in FIG.

  As shown in FIG. 8, tile patterns 701H and 709H are connected by a straight line 711 (in the drawing, a dotted line 711), and a perpendicular line is drawn from the tile pattern 702A to the straight line 711. By comparing the length of this perpendicular with the length of the perpendicular of the design value (when there is no deviation in the recording position), the inter-row deviation amount of the nozzle row A with respect to the nozzle row H is obtained. Similarly, the inter-row deviation amount of the other nozzle rows B to G with respect to the nozzle row H is obtained.

  In this way, by determining the relative positions of the tile patterns 702 to 708 of the other nozzle rows with reference to the straight line connecting the tile patterns 701H and 709H recorded at both ends of the nozzle row H, an error during paper conveyance can be obtained. The recording position deviation can be acquired in the removed state.

  In this embodiment, the inclination of the chip is obtained from the inclination of the straight line 711 read by the inspection unit 5 after pattern recording with respect to the Y axis (CCD sensor arrangement direction).

  The amount of shift in the recording position between the chips in the X direction is such that the straight line 711 is further extended from the tile pattern 709H and a perpendicular line is drawn from the tile pattern 710H recorded by the nozzle of the adjacent chip to the straight line 711. It is obtained by comparing with the length of the vertical line.

  The amount of shift in the recording position between chips in the Y direction is such that a line 712 perpendicular to the straight line 711 is drawn in the tile pattern 709H, and a vertical line is drawn from the tile pattern 710H to the line 712. By comparing with

  The displacement between chips differs for each nozzle array depending on the distance between the recording medium and the surface of the recording head on which the nozzle array is provided, the distance between the nozzle arrays, and the arrangement of the nozzle arrays. Therefore, the recording positions between chips are also measured in the other nozzle arrays A to G by measuring the relative positions of the tile patterns 701A to 701G, the tile patterns 709H to 709G, and the tile patterns 710A to 710G by the same method as described above. Find the deviation.

  The displacement amount (chipX) between the chips in the X direction is a value obtained by averaging the displacement amounts between the chips in the nozzle arrays A to H in the X direction.

  The amounts of displacement between the chips in the nozzle arrays A to H in the X direction are assumed to be chipX_A to chipX_H, respectively.

  Then, chipX = (chipX_A + chipX_B + chipX_C + chipX_D + chipX_E + chipX_F + chipX_G + chipX_H) / 8.

  Further, the shift amount (chipY) between the chips in the Y direction is a value obtained by averaging the shift amounts between the chips of the nozzle arrays A to H in the Y direction.

  The shift amounts of the recording positions between the chips in the nozzle rows A to H in the Y direction are respectively chipY_A to chipY_H.

  Then, chipY = (chipY_A + chipY_B + chipY_C + chipY_D + chipY_E + chipY_F + chipY_G + chipY_H) / 8.

  Thus, by obtaining the average value of the deviation amount between the chips for each nozzle row, even if the deviation amount of the printing position between the chips varies for each nozzle row, the total printing position between the chips. The deviation can be obtained with a value close to the central value of the variation of the plurality of nozzle rows. In the present embodiment, the shift amount between the chips of the eight nozzle rows is averaged to obtain the shift amount between the chips. Of the eight nozzle rows, the shift amount between the chips of some of the nozzle rows. May be averaged to determine the amount of deviation between chips.

  Further, the deviation between the chips may be corrected according to the deviation amount obtained by averaging, or may be corrected according to the deviation amount obtained for each nozzle row without averaging.

  In this embodiment, the recording position deviation between chips is obtained for each of a plurality of nozzle rows arranged on the chip. By doing so, it is possible to obtain an appropriate recording position deviation amount for each nozzle row even when the deviation amount of the recording position between chips differs for each nozzle row. Therefore, in the present embodiment, the print position deviation between the chips for each nozzle array can be appropriately corrected by obtaining the print position deviation amount for each nozzle array and correcting the print position accordingly.

  FIG. 9 is a schematic diagram for explaining a method for analyzing the pattern 505 shown in FIGS. 6A and 6C, and is a diagram for explaining a method for obtaining a deviation amount of a print position between print heads.

  In FIG. 9, (1) deviation between heads in the recording medium conveyance direction (X direction shown in the figure), (2) deviation between heads in the direction intersecting the X direction (Y direction shown in the figure), The method of analyzing is described.

  In the present embodiment, the shift amount of the recording position between the recording heads is obtained with reference to the tile pattern recorded by the nozzles of the recording head 14 (K). A line 806 connecting the tile pattern 801K recorded at the left end portion of the nozzle row H of the recording head 14 (K) and the tile pattern 805K recorded at the right end portion is drawn, and the nozzle row H of the recording head 14 (C) is drawn. A perpendicular line is drawn from the recorded tile pattern 802C to the line 806.

  The length of the perpendicular and the length of the desired perpendicular, that is, the design distance between the recording head (K) and the recording head (C) are compared, and the recording medium is conveyed in the conveyance direction (X direction in the figure). A deviation amount of the recording position of the recording head 14 (C) with respect to the recording head 14 (K) is obtained.

  A line 807 perpendicular to the line 806 is drawn from the tile pattern 801K, and a perpendicular line is drawn from the tile pattern 802C to the line 807. The length of the perpendicular and the length of the designed perpendicular are compared, and the deviation of the recording position of the recording head 14 (C) with respect to the recording head 14 (K) in the direction (Y direction in the figure) intersecting the transport direction is calculated. Ask.

  Similarly, for the recording heads 14 (M) and (Y), the amount of displacement of the recording position with respect to the recording head 14 (K) is obtained.

  Here, as shown in FIG. 6C, each tile pattern is recorded along a direction intersecting with the conveyance direction of the recording medium. The inspection unit 5 uses a CCD line sensor in which sensors are arranged along the Y direction that intersects the transport direction. Therefore, each tile pattern and the CCD line sensor that reads the tile pattern are arranged along the same direction.

  With such an arrangement, even when the size of an image to be read changes due to a conveyance error of the recording medium, the influence appears only in the conveyance direction, and a plurality of images arranged in the width direction of the recording medium. The size in the width direction hardly varies between the patterns. Therefore, the distance between tile patterns can be measured with high accuracy.

  Further, by arranging such tile patterns, the length of the tile pattern in the transport direction, that is, the length of the entire test pattern can be made relatively short.

  As described above, in this embodiment, the inspection unit 5 reads and analyzes the pattern. Then, the analysis result information is sent to the control unit 13. The control unit 13 obtains the recording position deviation amount from the information of the analysis result, determines a correction value for correcting the recording position deviation, and corrects the recording position according to the correction value. Control of each component for correcting the recording position deviation is performed by the control unit 13.

  Next, a method for correcting the recording position deviation will be described. The deviation of the recording position between the nozzle rows in the conveyance direction (X direction) of the recording medium is corrected by adjusting the ink ejection timing for each nozzle row in accordance with the deviation amount of the printing position with respect to the nozzle row H. The reference nozzle row is not limited to the nozzle row H, and any of the other nozzle rows A to G may be used as a reference.

  The tilt of the chip is corrected by shifting the recording data storage position of each nozzle in the transport direction in accordance with the tilt of the chip. More specifically, for example, when the reference head is a recording head (K), the individual head positions are set so that the inclinations of the recording heads (C), (M), and (Y) are matched with the inclination of the recording head (K). Accordingly, the timing for ejecting the recording data is shifted.

  As for the deviation between chips in the conveyance direction (X direction) of the recording medium, the recording position deviation amount of a chip having a portion overlapping with the chip with respect to one chip is obtained for each of a plurality of nozzle arrays, All nozzle rows in the chip are uniformly corrected according to the amount of deviation.

  Here, since the chips 101 to 108 in one recording head 14 are arranged in a staggered pattern so as to overlap, a deviation amount between a certain chip and a chip having a portion overlapping with the chip is It affects other chips. Therefore, the chip 106 shown in FIG. 4 performs correction by adding the correction amount for the chip 105 of the chip 101 to the correction amount for the shift amount with respect to the chip 101. The other chips are corrected similarly.

  The deviation between the chips in the direction (Y direction) intersecting with the conveyance direction is obtained by obtaining the recording position deviation amount of the chip having a portion overlapping with the chip with respect to one chip, and intersecting the conveyance direction according to this deviation amount. Correction is performed by adjusting the use area of the nozzle of each chip in the direction.

  FIG. 10 to FIG. 10 show a method for correcting the recording position deviation between chips when the chips are arranged in the direction that intersects the transport direction (Y direction / width direction of the recording medium) with an error in the design position. This will be described with reference to FIG.

  FIG. 10 is a schematic diagram showing a chip overlap area 900, and is an enlarged view of the chip 101 and the chip 105 in FIG. As described with reference to FIG. 4, the nozzles A to H are provided in the chips 101 and 105. The array resolution in the Y direction of each nozzle row is 1200 dpi (dot / inch), and the nozzle rows A, C, E, and G and the nozzle rows B, D, F, and H are a half pitch in the Y direction, that is, 2400 dpi. They are arranged shifted by one pixel.

  With such a configuration, an image having a resolution of 2400 dpi is recorded on the recording medium. In this embodiment, a case where the arrangement resolution of each nozzle row is 1200 dpi and the recording resolution is 2400 dpi will be described, but the resolution is not limited to this.

  FIG. 10 shows a state in which the chip 101 is arranged with respect to the chip 105 with no error in the design position. As shown in the figure, in the X direction, the nozzle arrays A, C, E, and G of the chip 101 and the nozzle arrays A, C, E, and G of the chip 105 are arranged on the same line in the X direction. As shown in the figure, in the X direction, the nozzle rows B, D, F, and H of the chip 101 and the nozzle rows B, D, F, and H of the chip 105 are also arranged on the same line in the X direction.

  In the figure, the filled nozzles 903 indicate nozzles that can record recording data common to the nozzle rows A, C, E, and G, and the nozzles 904 that are hatched indicate nozzle rows B, D, and F. , H represents nozzles capable of recording common print data.

  Of the overlapping area 900 between chips, the nozzles arranged in the area 901 in the chip 105 and the nozzles arranged in the area 902 in the chip 101 are used as adjustment nozzles for adjusting the recording position. In the present embodiment, as shown in FIG. 10, each row 4 nozzle located on the + side in the Y direction of the chip 101 and each row 4 nozzle located on the − side in the Y direction of the chip 105 in the overlapping region 900. Is used as an adjustment nozzle. As shown in FIG. 10, when there is no deviation in the Y direction between the chips, the region 901 and the region 902 are regions of 8 nozzles of 2400 dpi in the Y direction, respectively.

  FIG. 11 is a diagram for explaining a correction method, and shows a state in which the chip 101 is displaced by one pixel of 2400 dpi on the negative side in the Y direction with respect to the chip 105.

  Compared with the state of FIG. 10, when the chip 101 is displaced by 1400 dpi by 2400 dpi with respect to the chip 105, the same line extending in the X direction in the nozzle row of the chip 101 and the nozzle row of the chip 105 is the same as FIG. Recording is not possible with the combined nozzle. That is, in the X direction, the nozzle rows A, C, E, G of the chip 105 and the nozzle rows B, D, F, H of the chip 101 are arranged on the same line, and the nozzle rows B, D, F, H of the chip 105 are arranged. And nozzle rows A, C, E, and G of the chip 101 are arranged on the same line.

  In the case where they are shifted in this way, in order to correct this shift amount, the recording data of all the nozzle arrays A to H of the chip 101 are shifted by one nozzle (1200 dpi) in the Y direction + side. In the chip 101, the recording data for the nozzle arrays A, C, E, and G and the recording data for the nozzle arrays B, D, F, and H are exchanged.

  By doing so, as shown in FIG. 11, the nozzle 903 of the chip 105 and the nozzle 903 of the chip 101 are arranged on the same line in the X direction, and the nozzle 904 of the chip 105 and the nozzle 904 of the chip 101 are also arranged on the same line. To do. By this method, it is possible to correct a deviation between chips when the pixel is shifted by one pixel of 2400 dpi on the negative side in the Y direction.

  In FIG. 11, since the print data of the nozzle row is shifted by one nozzle in the Y direction + side, the corrected nozzle area 902a of the chip 101 is a 7-pixel area in the Y direction. Compared to the case shown in FIG.

  FIG. 12 is a diagram for explaining another example of the correction method, and shows a state in which the chip 101 is shifted by one pixel of 1200 dpi (that is, two pixels of 2400 dpi) with respect to the chip 105. When the chip 101 is shifted by two pixels with respect to the chip 105, the recording data for all the nozzle rows A to H of the chip 101 is shifted in the Y direction + side by the two pixels (one nozzle) where the shift occurs. To shift. By doing so, deviation between chips can be corrected.

  As described above, when the shift between chips in the Y direction is shifted by an odd number of pixels of 2400 dpi, the print data is shifted by the number of pixels in which the shift occurs, and the nozzle rows A, C, E, and G are shifted. The recording data and the recording data for the nozzle rows B, D, F, and H are exchanged. If there is a shift by an even number of pixels, the recording data is shifted by the nozzle for which the shift has occurred.

  The above-described displacement between chips in the Y direction is corrected by shifting the recording data for each nozzle in the Y direction. That is, as described above, the deviation between the chips in the Y direction can be corrected by adjusting the use area of the nozzles in the Y direction.

  As described above, the amount of deviation between a certain chip and a chip having a portion overlapping with the chip also affects other chips. Therefore, the chip 106 shown in FIG. 4 performs correction by adding the correction amount for the chip 105 of the chip 101 to the correction amount for the shift amount with respect to the chip 101. The other chips are corrected similarly.

  In the description of the correction method, the amount of deviation of the chip 101 is obtained with the chip 105 as a reference, but the amount of deviation of the chip 105 may be obtained with the chip 101 as a reference. That is, there is no particular limitation as to which chip is used as a reference as long as the deviation amount between chips having overlapping portions can be obtained.

  The recording position shift amount in the X direction between the recording heads is obtained with reference to the recording head 14 (K). The ejection timing from the nozzles of each recording head 14 (C, M, Y) is adjusted according to the amount of deviation. The amount of deviation of the recording position in the Y direction between the recording heads is also obtained with reference to the recording head 14 (K). The storage position of the recording data of the nozzles of each recording head 14 (C, M, Y) is shifted in the Y direction according to the amount of deviation.

  Each recording head is provided with the adjustment nozzles described in the correction method for inter-chip deviation in the Y direction at both ends thereof. Therefore, by using this adjustment nozzle, the recording position shift in the Y direction between the recording heads is corrected in the same manner as when correcting the shift between chips.

  Note that the deviation amount of the recording position between the recording heads may be obtained with reference to any one of the recording heads 14 (C, M, Y) other than the recording head 14 (K).

  As described above, in the present embodiment, the recording position deviation within one recording head and the recording position deviation between the recording heads are respectively obtained. In the present embodiment, from a series of test patterns shown in FIG. 6A, the displacement between nozzle rows, the inclination of the chip, the displacement between chips, and the recording position between the recording heads in one recording head. The deviation is analyzed, and the deviation of the recording position is corrected based on the analysis result.

  At this time, the recording position deviation between the chips is obtained with reference to the plurality of nozzle arrays arranged in each chip, and the average value of the recording position deviation between the chips obtained by each of the plurality of nozzle arrays is calculated as the chip. The total recording position deviation is between. By doing so, even if the recording position shift amount between chips differs for each nozzle row, an appropriate recording position shift amount can be obtained. Therefore, in the present embodiment, it is possible to correct the recording position deviation according to an appropriate recording position deviation amount.

(Second Embodiment)
The second embodiment will be described below. In the present embodiment, the arrangement of tile patterns is different from that in the first embodiment. Others are the same as those in the first embodiment, and the description thereof is omitted.

  FIGS. 13A and 13B are schematic views showing examples of test pattern recording in the present embodiment. FIG. 13A shows a pattern layout for measuring the deviation of the recording position. b) is an enlarged view of the pattern 501 in FIG. As shown in FIGS. 4A and 4B, in the present embodiment, the tile pattern at the right end of each nozzle row is recorded while being shifted in the Y direction in the overlapping region 905.

  In the overlapping area 905 of the chip 104 and the chip 108 in FIG. 5A, the tile pattern recorded by the right side of the nozzle arrays A to H of the chip 104 is moved in the Y direction as it goes from the downstream side in the X direction to the upstream side. It is recorded while shifting. In the overlapping area 905 of the chip 108 and the chip 103, the tile pattern recorded by the right side of the nozzle arrays A to H of the chip 108 is recorded while shifting in the Y direction from the downstream side in the X direction toward the upstream side. . Similarly, tile patterns are recorded between other chips.

  The recording position associated with the air flow during ejection as described above is particularly unstable near the end of the nozzle row (ie, the overlapping region), and changes depending on the position in the nozzle row (distance from the end). To do. Therefore, in this embodiment, in order to improve the accuracy of the recording position deviation amount by acquiring the recording position deviation information uniformly from the end region where the recording position deviation is unstable, a plurality of stages shifted in the Y direction step by step. Prepare the pattern.

  The amount of deviation between the chips is comprehensively determined from the amount of deviation between the chips for each nozzle row, as in the example of the first embodiment. However, in the present embodiment, the total recording position deviation between chips is obtained by performing weighted averaging on a plurality of recording position deviations obtained from each nozzle row.

  The displacement amount (chipX) between the chips in the X direction is a value obtained by weighted averaging the displacement amounts between the chips of the nozzle arrays A to H in the X direction as follows.

  The shift amounts between the chips of the nozzle arrays A to H in the X direction are respectively chipX_A to chipX_H, and the weighting coefficients for the shift amounts are a to h.

  Then, chipX = a * chipX_A + b * chipX_B + c * chipX_C + d * chipX_D + e * chipX_E + f * chipX_F + g * chipX_G + h * chipX_H.

  Here, it is assumed that a + b + c + d + e + f + g + h = 1 and g <d.

  Further, the displacement amount (chipY) between the chips in the Y direction is a value obtained by weighted averaging the displacement amounts between the chips of the nozzle arrays A to H in the Y direction.

  The shift amounts of the recording positions between the chips of the nozzle arrays A to H in the Y direction are respectively chipY_A to chipY_H, and the weighting coefficients for the shift amounts are a ′ to h ′.

  Then, chipY = a ′ · chipY_A + b ′ · chipY_B + c ′ · chipY_C + d ′ · chipY_D + e ′ · chipY_E + f ′ · chipY_F + g ′ · chipY_G + h ′ · chipY_H.

  Here, it is assumed that a ′ + b ′ + c ′ + d ′ + e ′ + f ′ + g ′ + h ′ = 1 and g ′ <d ′.

  The weighting coefficients g and g ′ for the pattern G recorded at the extreme end of the nozzle row are kept relatively lower than the weighting coefficients d and d ′ of the pattern recorded at the center.

  By the way, in a recording head in which a plurality of chips are arranged while providing an overlapping area with each other, gradation is gradually applied from one chip to the other chip in the overlapping area with the frequency of use of nozzles included in each nozzle row. It is common to move to That is, the frequency of use of the nozzle located at the endmost part in the same overlapping region is lower than the frequency of use of the nozzle located relatively at the center.

  Therefore, in the present embodiment, the weighting coefficients g and g ′ for the pattern G recorded at the endmost part of the nozzle row are kept lower than the weighting coefficients d and d ′ of the pattern recorded at the relatively central part. The information obtained from the high frequency area is relatively emphasized.

  As described above, in this embodiment, the recording position deviation amount of each chip is set to the weighted average of the recording position deviations corresponding to the plurality of nozzle arrays obtained from the plurality of tile patterns recorded at different positions in the Y direction. Calculated by

  In this embodiment as well, the amount of deviation between chips in the eight nozzle rows is obtained by weighted average of the amounts of deviation between the chips in the eight nozzle rows. The amount of deviation between chips may be obtained by weighted averaging of the amounts.

5 Inspection Unit 13 Control Unit 14 Recording Head 20 Recording Device 101-108 Chip 501-504 Pattern

Claims (8)

An inkjet recording apparatus that records an image using a recording head in which a plurality of chips each having a plurality of nozzle arrays in which nozzles for ejecting ink are arrayed intersects with the direction in which the nozzle arrays are arrayed.
Means for recording a pattern for detecting a shift in the recording position between the chips for each nozzle row;
Means for reading the recorded pattern;
Means for analyzing the read result of the pattern;
Means for determining a recording position shift amount between the chips for each nozzle row from the analysis result of the pattern, and determining a correction value for correcting the recording position shift between the chips;
An ink jet recording apparatus comprising:   2. The ink jet recording apparatus according to claim 1, wherein the correction value is a value obtained by averaging at least a part of a recording position shift amount between the chips for each nozzle row.   The ink jet recording apparatus according to claim 1, wherein the correction value is determined for each nozzle row in accordance with a recording position shift amount between the chips for each nozzle row. A plurality of recording heads that are arranged in parallel in a direction intersecting with the arrangement direction of the nozzle rows and that respectively record different color inks,
Means for recording a pattern for detecting a shift in recording position between the plurality of recording heads;
Means for reading the recorded pattern;
Means for analyzing the read result of the pattern;
Means for determining a recording position deviation amount between the plurality of recording heads from the analysis result of the pattern, and determining a correction value for correcting the recording position deviation;
The inkjet recording apparatus according to any one of claims 1 to 3, further comprising: The chip is arranged so as to have an overlapping region overlapping with other chips in a direction intersecting the arrangement direction of the nozzle row,
In the overlapping area, the pattern recorded by the nozzles of one chip is recorded while shifting the position in the direction intersecting the transport direction as it goes from the upstream side to the downstream side in the transport direction of the recording medium on which the pattern is recorded. The inkjet recording apparatus according to claim 1, wherein:   6. The correction value is a value obtained by weighting and averaging a recording position shift amount between the chips for each nozzle row in accordance with a printing position for recording the pattern for each nozzle row. 2. An ink jet recording apparatus according to 1.   In the overlapping region, the weighting coefficient for the shift amount of the recording position of the nozzle row that records the pattern recorded by using the nozzle at the end in the arrangement direction in the one chip is the weighting coefficient in the one chip. The inkjet recording apparatus according to claim 6, wherein the weighting coefficient is smaller than a weighting coefficient with respect to the recording position deviation amount of the nozzle row that records the pattern recorded using the nozzles in the relatively central portion in the arrangement direction. Using a recording head in which a plurality of chips having a plurality of nozzle arrays in which nozzles for ejecting ink are arrayed in a direction intersecting the array direction of the nozzle arrays are used, the recording position shift of an inkjet recording apparatus that records an image A correction method,
Recording a pattern for detecting a shift in the recording position between the chips for each nozzle row;
Reading the recorded pattern;
Analyzing the read result of the pattern;
Obtaining a recording position shift amount between the chips for each nozzle array from the pattern analysis result, and determining a correction value for correcting the recording position shift between the chips;
Correcting the recording position according to the correction value;
A method of correcting a recording position deviation, comprising: