JP2017047644A - Inkjet recording device and recording control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording device that can perform complementary processing at high speed by moving image data to be recorded by a malfunctioning nozzle to an adjacent pixel.SOLUTION: An inkjet recording device, which allows image data corresponding to one ink color to be separately recorded in two nozzle rows, if nozzles constituting a first nozzle row 210 are found to malfunction on the basis of information about the nozzles determined to have malfunctioned, moves pixel data 600 to be recorded by the malfunctioning nozzles to a pixel 610 to be recorded by an adjacent nozzle, in a range of a first pixel group to be recorded by the first nozzle row 210; and if nozzles constituting a second nozzle row 217 are found to have malfunctioned, moves pixel data 601 to be recorded by the malfunctioning nozzles to a pixel to be recorded by an adjacent nozzle, in a range of a second pixel group to be recorded by the second nozzle row 217.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a method of complementing a malfunctioning nozzle in an inkjet recording apparatus with an adjacent nozzle.

  Conventionally, when an ink jet recording apparatus forms an image at a high speed with few recording operations, it has a configuration in which one ink color can be recorded by a plurality of recording nozzle arrays arranged in parallel in the same recording area, and input image data is stored. There is known a method of recording an image by distributing to a plurality of recording nozzle arrays. In an ink jet recording apparatus having such a recording nozzle array configuration, when one or more malfunctioning nozzles are identified, the pixel data recorded by the malfunctioning nozzles can be recorded in the same position. A method of compensating by moving to pixel data of a recording nozzle row is known (Patent Document 1).

Japanese Patent Laid-Open No. 10-6488

  However, in Patent Document 1, after the image data divided for every recording nozzle row is held, the image data recorded by the malfunctioning nozzle is moved to the image data of another recording nozzle row. Since the image data for the recording nozzle array is larger than the image data, the storage area for holding the image data is increased. Moreover, since it is necessary to perform calculation processing for moving pixel data between the image data of two divided nozzle rows, there is a problem that processing time increases.

In order to solve the above problems, an ink jet recording apparatus according to the present invention includes:
In an ink jet recording apparatus that records image data corresponding to one ink color using a plurality of nozzle rows, the plurality of nozzle rows are arranged apart by a distance in a direction perpendicular to the direction in which the nozzles are arranged, and The same region of the image data is recorded by the plurality of nozzle rows by the recording operation, and means for detecting the discharge state of each nozzle for the plurality of nozzle rows and the detection result of the discharge state Means for storing nozzle information determined to be malfunctioning from the first pixel group recorded in the first nozzle row of the plurality of nozzle rows, or the plurality of the target pixels of the input image data, Means for determining one of the second pixel groups recorded by the second nozzle row of the nozzle row of the nozzle row, and malfunctioning nozzles in the nozzles constituting the first nozzle row based on the nozzle information In the first pixel group, the pixel data recorded by the malfunctioning nozzle is moved to the pixel recorded by the nozzle adjacent to the malfunctioning nozzle of the first nozzle row, and the nozzle When there is a malfunctioning nozzle in the second nozzle row based on the information, the pixel data recorded by the malfunctioning nozzle in the second pixel group is stored in the second nozzle row. And a means for moving recording data to a pixel recorded by a nozzle adjacent to the malfunctioning nozzle, and a means for recording an image on a recording medium based on the image data after the recording data movement processing. .

  According to the ink jet recording apparatus of the present invention, in the ink jet recording apparatus that records an image by dividing the input image data corresponding to one ink color into a plurality of nozzle rows, the image data recorded by the malfunctioning nozzle is used as the ink. By moving to the adjacent pixels in the decomposed image data and performing the complementing process, the calculation process can be executed at high speed with a simple configuration.

1 is a block diagram illustrating a schematic configuration of a recording control system of an inkjet recording apparatus. FIG. 3 is a perspective view illustrating a configuration around a recording head. FIG. 3 is a diagram illustrating a nozzle array configuration of a recording head. It is a figure which shows the block configuration of a recording control part. It is a figure explaining the method of dividing | segmenting input image data into a some nozzle row. It is a figure which shows the priority of the image data movement destination of a malfunctioning nozzle. It is a figure explaining the result of having corrected pixel data recorded with a malfunctioning nozzle. It is a complementation processing flowchart of input pixel data. It is a flowchart which complements the pixel data recorded by a malfunctioning nozzle. It is a figure explaining the method of dividing | segmenting input image data into a some nozzle row. It is a figure which shows the priority of the image data movement destination of a malfunctioning nozzle. It is a figure explaining the result of having corrected pixel data recorded with a malfunctioning nozzle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the present invention according to the claims, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the present invention. . The same constituent elements are denoted by the same reference numerals, and the description thereof is omitted.

[First Embodiment]
FIG. 1 is a block diagram showing a schematic configuration of a recording control system of an ink jet recording apparatus.

  The inkjet recording apparatus 100 is connected to an external host computer (host PC) 108 via an interface 107 so as to be able to communicate with each other. The host PC 108 is a data supply device and transmits image data to be recorded, control commands, and the like to the inkjet recording device 100. Various data and control commands transmitted from the host PC 108 are input to the recording control unit 101 of the inkjet recording apparatus 100. The recording control unit 101 controls a recording unit (printer engine) such as the recording head 111 so as to perform recording based on the input image data.

  The recording control unit 101 performs various image processing (color space conversion, resolution conversion, binarization processing, etc.) for converting the image data transmitted from the host PC 108 into recording data. The recording control unit 101 includes a memory 110, a CPU 109 (which may be an ASIC), a ROM, and a RAM. The CPU 109 comprehensively controls each unit of the ink jet recording apparatus 100 and controls the motor drivers 102 to 103 and the recording head driver 106 in accordance with a control command input via the interface 107, for example.

  The conveyance motor 104 is a conveyance motor for rotating a conveyance roller 202 that conveys a recording medium 201 such as printing paper. The carriage motor 105 is a carriage motor for reciprocating the carriage 205 on which the recording head 111 is mounted in the main scanning direction. Here, the main scanning direction is a direction that intersects the conveyance direction of the recording medium 201. Motor drivers 102 and 103 are drivers for driving the transport motor 104 and the carriage motor 105, respectively. The recording head driver 106 is a driver for driving the recording head 111, and a plurality of recording head drivers 106 may be provided corresponding to the number of recording heads. The recording head driver 106 includes various control circuits such as a selector and a decoder for controlling the supply voltage to the heater provided in the nozzle. The recording control unit 101 and the recording head driver 106 are connected by, for example, a flexible cable.

  FIG. 2 is a perspective view showing a configuration around the recording head 111 of the inkjet recording apparatus 100.

  The recording head 111 in this embodiment is a so-called serial type recording head that performs recording by ejecting ink droplets from nozzles while scanning in a direction X that intersects the conveyance direction Y of the recording medium 201. In the present embodiment, for example, the ink tanks 206 to 209 store four colors of ink (black, cyan, magenta, yellow: CMYK), respectively, and these four colors of ink are stored in the recording heads 210 to 217. It can be supplied. The recording heads 210 to 217 are provided so as to correspond to the four color ink tanks 206 to 209 and are configured to be able to discharge ink supplied from the ink tanks 206 to 209 from nozzles (discharge ports). The recording heads 210 to 217 correspond to the recording head 111 in FIG. Hereinafter, the recording heads 210 to 217 may be collectively referred to as the recording head 111.

  The conveying roller 202 rotates while sandwiching the recording medium 201 together with the auxiliary roller 203 to convey the recording medium 201 and also has a role of holding the recording medium 201. The carriage 205 can mount ink tanks 206 to 209 and recording heads 210 to 217, and these recording heads and ink tanks are mounted so as to be reciprocally movable along the main scanning direction X. An image is recorded on the recording medium 201 by ejecting ink droplets from the nozzles of the recording heads 210 to 217 during the reciprocating movement of the carriage 205. During a non-recording operation such as a recovery operation of the recording heads 210 to 217, the carriage 205 is controlled to stand by at a home position h indicated by a dotted line in the drawing.

  When the recording heads 210 to 217 standing by at the home position h shown in FIG. 2 receive the recording start command, the recording heads 210 to 217 move in the main scanning direction X together with the carriage 205 to eject ink droplets to form an image on the recording medium 201. Record. By one movement (scanning) of the recording heads 210 to 217, recording is performed on an area having a width corresponding to the nozzle arrangement range (arranged in the direction intersecting the main scanning direction X) of the recording heads 210 to 217. Is called. When the recording associated with one scan of the carriage 205 in the main scanning direction X is completed, the carriage 205 returns to the home position h and performs recording by the recording heads 210 to 217 while scanning in the main scanning direction X again.

  The conveyance roller 202 rotates and the recording medium 201 is conveyed in the sub-scanning direction Y intersecting with the main scanning direction X from the end of the previous recording scan to the start of the subsequent recording scan. In this way, an image is recorded on the entire surface of the recording medium 201 by repeating the recording scanning of the recording heads 210 to 217 and the conveyance of the recording medium 201. The ejection operation for ejecting ink droplets from the nozzles of the recording heads 210 to 217 is performed under the control of the recording head driver 106 by the recording control unit 101.

  In the above description, the case where so-called one-way recording is performed, in which the recording operation is performed only when the recording head 111 scans in the forward direction, has been described. However, the recording head 111 may perform so-called bidirectional recording in which recording is performed both when scanning in the forward direction and when scanning in the backward direction. In the above description, the ink tanks 206 to 209 and the recording heads 210 to 217 are mounted on the carriage 205 in a separable manner. However, a cartridge in which the ink tanks 206 to 209 and the recording heads 210 to 217 are integrated may be mounted on the carriage 205.

  Furthermore, a configuration in which a recording head of a plurality of color integrated types capable of discharging a plurality of colors of ink from one recording head is mounted on the carriage 205 may be employed. Further, the configuration in which the ink is supplied from one ink tank to the recording heads that record the same ink among the recording heads 210 to 217 is shown, but the ink is supplied from individual ink tanks. There may be.

  FIG. 3 is a diagram illustrating an example of a nozzle array configuration of the recording heads 210 to 217.

  A nozzle 301 indicates an ink droplet ejection port, and each recording head has 16 nozzles arranged in a row. In the present embodiment, the number of nozzles and the number of nozzle rows are determined as shown in FIG. 3, but the number of nozzles and the number of nozzle rows shown in FIG. Further, the order of the ink colors arranged in the recording heads 210 to 217 is an example, and the combination shown in FIG. 3 is not necessary.

  FIG. 4 is a diagram showing a block configuration relating to print mask control of the recording control unit 101.

  The CPU 109 and the memory 110 are connected via the bus 403. The memory 110 stores image data 401 to be recorded and malfunctioning nozzle data 402 described later. The CPU 109 reads each data from the memory 110 and corrects the image data 401 according to the malfunctioning nozzle. The ROM 404 stores a program executed by the CPU 109 and the like. The RAM 405 is used as a working memory for the CPU 109. The CPU 109 reads out and executes the program stored in the ROM 404, thereby realizing the operation of each embodiment.

  FIG. 5 is a diagram showing image data 410 recorded by the recording heads 210 and 217 including the nozzle rows that discharge cyan ink among the recording heads 210 to 217.

  In this embodiment, the image data 410 is binarized data, and an example in which the presence / absence of recording of each pixel is represented by 0 and 1 is shown. The image data is recorded for the length of the nozzle array by one scan of the recording head, and the case where the image is recorded by one-pass recording in which the recording medium for the length of the nozzle array is conveyed after the recording scan is shown. .

  At this time, among the recording heads that discharge cyan ink, the nozzle row of the recording head 210 is A, the nozzle row of the recording head 217 is B, and among the cyan ink recording image data 410, the even column 420 (the image of FIG. 5). Data E column E, pixels painted with diagonal lines) are assigned to nozzle row A, and odd number column 421 (image data 410 O row, white pixels in FIG. 5) is assigned to nozzle row B for recording. To do.

  FIG. 6 is a diagram showing which pixel is prioritized when data is moved to an adjacent pixel and complemented with respect to pixel data assigned to a malfunctioning nozzle.

  As indicated by the crosses in FIG. 6, when image data is assigned to nozzles in even-odd column units, only one of the even column or odd column is assigned to a certain malfunctioning nozzle. In the example illustrated in FIG. 6, it is assumed that the pixels 500 recorded in the second seg of the nozzle row A and the pixels 501 recorded in the thirteenth seg of the nozzle row B are assigned to the malfunctioning nozzles. In order to move the data of these pixels to the adjacent normally operating nozzles, it is only necessary to move to the vertically adjacent pixels in the same column of the target pixel.

  However, if the movement is biased to either one, the raster recorded by the malfunctioning nozzle becomes blank and the density decreases, and the density increases as the raster data recording dot increases. This makes the stripes stand out. For this reason, the pixels are evenly allocated to the upper and lower pixels of the malfunctioning nozzle, and the uniformity of density is improved as compared with the case of moving to only one of them, and the streak caused by the data correction is less noticeable. Further, since the deviation of the nozzles to be operated is reduced, it is possible to prevent a decrease in nozzle life.

  Therefore, in this embodiment, the data movement priority 510 is alternately switched for every even column or odd column. In FIG. 6, pixels adjacent to each column in the direction indicated by the arrow are set as the first priority pixels for data movement, the 2n-th (n = 0, 1, 2,...) Column is upper for each even-odd column, and the 2n + 1st column is First, it is determined whether data movement is possible. If the destination pixel is a non-recording pixel, it is corrected to a recording pixel, and if it is already a recording pixel, it is determined whether or not it can be moved to the pixel on the opposite side of the malfunctioning nozzle, which is the second priority. If the second priority pixel is already a recording pixel, the data is not moved.

  FIG. 7 is a diagram for explaining the result of correcting the image data recorded by the malfunctioning nozzle by the above method.

  The example of FIG. 7 shows a case where the second seg of the nozzle row A and the thirteenth seg of the nozzle row B are malfunctioning. Since the nozzle row A records even columns of the image data 410, image data 600 (pixels indicated by crosses in FIG. 7) in the even columns among the rasters to which the second segment is assigned cannot be recorded. Further, since the nozzle row B records the odd columns of the image data 410, the image data 601 in the odd columns among the rasters to which the 13th segment is assigned cannot be recorded.

  When the image data determined to be unrecordable is corrected based on the priority order of the movement destination shown in FIG. 6, the image data becomes 411, and the image recorded in the second seg of the nozzle array A The data 600 moves to the pixel 610 painted with halftone dots, and the image data 601 recorded in the 13th segment of the nozzle row B moves to the pixel 611 painted with diagonal lines.

  In this example, image data recorded with cyan ink is shown as an example. However, the same processing is applied to image data recorded with magenta, yellow, and black inks to compensate for malfunctioning nozzles. It can be carried out.

  By the above method, the binary image data input to each ink is corrected in pixel data assigned to the malfunctioning nozzle with respect to the raster corresponding to the length of the nozzle row when the recording head is scanned. In the corrected image data, the data for the columns allocated to the respective nozzle rows is transferred to the print buffer, and based on this, the image is recorded from each nozzle row.

  FIG. 8 shows a data flow of complementary processing of input image data, and FIG. 9 is a flowchart showing a processing flow of moving pixel data recorded by the above-mentioned malfunctioning nozzles to adjacent pixels and complementing them.

  In this embodiment, the operation of complementing the malfunctioning nozzle is started in step S1100 before the start of each recording operation. In steps S1101 and S1102, the input image data 401 and the malfunctioning nozzle information 402 are acquired from the memory 109, and then malfunctioning nozzle supplement processing is executed in step S1103.

  In the malfunction nozzle complementing process, first, in step S1201, it is determined based on the malfunction nozzle information 402 whether there is an unprocessed pixel data to be recorded with the malfunction nozzle for the target ink color to be subjected to the complement process. To do. If there is unprocessed data, pixel data to be recorded by the malfunctioning nozzle to be processed is selected in step S1202, and candidate pixels to which the image data is to be moved are selected based on the movement priority as shown in FIG. decide. In step S1203, it is determined whether the movement candidate pixel is a recording pixel or a non-recording pixel.

  In the case of a recording pixel, it is determined in step S1204 whether or not there is a next movement candidate destination. If there is an undetermined movement candidate destination, in step S1206, the target pixel is moved to the next higher priority candidate destination pixel. If all the movement candidates are recording pixels, the pixel recorded by the malfunctioning nozzle that was the processing target in step S1207 is set as a non-recording pixel, and the process proceeds to the next processing target pixel. If it is determined in step S1203 that the movement candidate pixel is not recorded, the movement candidate destination pixel is changed to a recording pixel, and the process proceeds to the next processing target pixel.

  In step S1201, if processing has been completed for all pixels recorded by the malfunctioning nozzle of the target ink color, it is determined in step S1208 whether processing has been completed for all ink colors, and unprocessed ink colors are determined. If there is, the process target color is changed to the next ink color in step S1209, and the defective nozzle complement process is executed in step S1201 and subsequent steps. If the process has been completed for all ink colors in step S1208, this process ends.

  The image data processed in the above-described malfunction nozzle complementing process S1103 is stored in the memory 109 as recorded image data of each color in step S1104. In addition, since the recording image data is read and divided for each nozzle row by reading only even or odd columns, it is not necessary to hold the recording image data in a divided state for each nozzle row.

  As described above, according to the present embodiment, in the recording operation in which one ink color is divided and recorded by a plurality of nozzle rows, the interpolation processing of the pixel data recorded by the malfunctioning nozzle is performed using the ink color. It is possible to process on unit image data. As a result, the number of processing calculations is reduced as compared to the case where image data is held for each nozzle row and complement processing is performed, and a decrease in recording speed due to calculation processing is prevented in a high-speed recording operation mode such as one-pass recording. be able to. Further, the memory capacity can be reduced as compared with the case where image data is held for each nozzle row. In addition, by selectively processing only the pixels recorded by the malfunctioning nozzles, the pixels recorded by the normal nozzles are not unnecessarily complemented, and image quality deterioration can be suppressed.

[Second Embodiment]
In the present embodiment, in a method of dividing image data of one ink color into a plurality of nozzle rows and recording an image of a recording area by one scan of the recording head, the image data is based on the driving order of time-division driving. A description will be given of a complementary processing method for malfunctioning nozzles when dividing into a plurality of nozzle rows.

  FIG. 12 is a diagram showing a method of dividing cyan image data into nozzle row A and nozzle row B in the order of time division driving.

  In the example shown in FIG. 10, it is assumed that the number of nozzles that can be driven by the recording head during scanning in each column is 8 out of 16 nozzles, and half of them can be driven. For example, if the nozzle row A is driven in the following order: 0, 4, 8, 12, 1, 5, 9, 13, 2, 6, 10, 14, 3, 7, 11, 15 The first 8 nozzles are driven by even columns, and the latter 8 nozzles are driven by odd columns. On the other hand, the nozzle row B is driven in the order of 2, 6, 10, 14, 3, 7, 11, 15, 0, 4, 8, 12, 1, 5, 9, 13, for example, Image data can be recorded so as to complement the pixels recorded by the column A.

  When the image data is divided by time-division driving in this way, the nozzle row A records the pixels 430 painted with diagonal lines in FIG. 10, and the nozzle row B records the white pixels 431.

  However, in the image data divided by the above-described method, if the interpolation process is performed by moving the pixel data recorded by the malfunctioning nozzle to an adjacent pixel, the pixels adjacent to the pixel to be complemented are not necessarily the same. It is not always recorded with the nozzle row. In the division pattern of the image data shown in FIG. 10, the upper and lower adjacent pixels of the pixel recorded by the malfunctioning nozzle are recorded by the same nozzle row as the malfunctioning nozzle, but the other neighboring pixel is different Recorded by nozzle row. Therefore, in order to move the data to the pixels recorded by the same nozzle row and complement the data, it is necessary to move to the adjacent column.

  FIG. 11 is a diagram showing the priority order 530 of the data movement candidate pixels in consideration of the case where the image data recorded by the malfunctioning nozzle cannot be moved to the vertically adjacent pixels. The pixels in the first priority order are pixels that are vertically adjacent to the complementary processing target pixel 520 and are recorded by the same nozzle row. Since the other upper and lower adjacent pixels are not recorded by the same nozzle, the second priority order candidate pixel is adjacent to the first priority order candidate pixel in the upside down direction, and is further adjacent to the left and right columns. .

  In this case, either the left or right is given the second priority, and the other is given the third priority. In this embodiment, the left side is the second priority order, and the right side is the third priority order. When there is no adjacent column such as an image edge, only the direction opposite to the edge is set as a movement candidate. Depending on the driving order of time-division driving, there may occur a case where both the upper and lower adjacent pixels are not recorded by the same nozzle row. In that case, the pixels adjacent to each other in the upper and lower directions are not subject to movement, and the pixels that are obliquely adjacent are given priority according to a certain rule.

  FIG. 12 is a diagram showing a result of correcting the image data by moving the pixel data recorded by the malfunctioning nozzle to the pixels recorded by the same nozzle row by the complementary processing of the present embodiment.

  Here, it is assumed that the second and 13th nozzles in the nozzle array A are malfunctioning. In that case, the pixel 600 recorded in the second segment and the pixel 601 recorded in the thirteenth segment move to the pixel 610 and the pixel 611 in the corrected image data 411 after the complement processing, respectively. Note that pixel data in which the movement candidate destinations are all recording pixels is not recorded.

  By the above method, the binary image data input to each ink is corrected in pixel data assigned to the malfunctioning nozzle with respect to the raster corresponding to the length of the nozzle row when the recording head is scanned. The corrected image data is transferred to the print buffer of each nozzle row, and an image is recorded from each nozzle row based on the image data and block driving.

  As described above, according to the present embodiment, the same effect as that of the first embodiment can be obtained even in a recording operation in which one ink color is divided and recorded based on block driving with a plurality of nozzle rows. be able to.

100 inkjet recording apparatus, 101 recording control unit, 109 CPU,
110 memory, 404 ROM, 405 RAM

Claims (6)

  In an ink jet recording apparatus that records image data corresponding to one ink color using a plurality of nozzle rows, the plurality of nozzle rows are arranged apart by a distance in a direction perpendicular to the direction in which the nozzles are arranged, and The same region of the image data is recorded by the plurality of nozzle rows by the recording operation, and means for detecting the discharge state of each nozzle for the plurality of nozzle rows and the detection result of the discharge state Means for storing nozzle information determined to be malfunctioning from the first pixel group recorded in the first nozzle row of the plurality of nozzle rows, or the plurality of the target pixels of the input image data, Means for determining one of the second pixel groups recorded by the second nozzle row of the nozzle row of the nozzle row, and malfunctioning nozzles in the nozzles constituting the first nozzle row based on the nozzle information In the first pixel group, the pixel data recorded by the malfunctioning nozzle is moved to the pixel recorded by the nozzle adjacent to the malfunctioning nozzle of the first nozzle row, and the nozzle When there is a malfunctioning nozzle in the second nozzle row based on the information, the pixel data recorded by the malfunctioning nozzle in the second pixel group is stored in the second nozzle row. And a means for moving recording data to a pixel recorded by a nozzle adjacent to the malfunctioning nozzle, and a means for recording an image on a recording medium based on the image data after the recording data movement processing. Inkjet recording device.   2. The ink jet recording apparatus according to claim 1, wherein the image data is divided into even columns and odd columns in a column unit, and is divided into a first pixel group and a second pixel group.   3. The ink jet recording apparatus according to claim 2, wherein the pixel data recorded by the malfunctioning nozzle is alternately distributed to an upstream adjacent pixel and a downstream adjacent pixel.   4. The pixel data recorded by the malfunctioning nozzle distributes pixel data to adjacent pixels on the opposite side when adjacent pixels to be moved are already recorded pixels. 5. Inkjet recording device.   2. The image data is allocated to a first pixel group recorded by a first nozzle row and a second pixel group recorded by a second nozzle row in a time division drive order. 2. An ink jet recording apparatus according to 1. In the pixel data recorded by the malfunctioning nozzle, when the adjacent pixel to be moved is a pixel recorded by another nozzle row, the image data is moved to the pixel in the column adjacent to the moving target pixel. The inkjet recording apparatus according to claim 5.