JP2016124257A - Recording device and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording device that can detect exactly non-discharge using non-discharge detection patterns when recording a pattern for detecting conveyance amounts and the non-discharge detection patterns.SOLUTION: Timing at which a pattern 420 for detecting conveyance amounts is controlled so that the pattern for detecting the conveyance amounts does not overlap with non-discharge detection patterns 410.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a recording apparatus and a recording method.

  In order to print on the conveyed media with high quality, the accuracy of the image print position is important. For example, when printing with a plurality of colors, it is necessary to realize printing with less color misregistration by accurately matching the print positions of the respective colors. Further, in the case of a dot printer, it is required to accurately align the print position within the same color to reduce dot deviation and to realize a monochromatic character quality with a sharp outline.

  In a printer of a type in which printing is performed by an ink jet print head fixed on a medium that is transported at a constant speed, if a transport error occurs, the print position is shifted. For this reason, it is necessary to provide means for detecting the transport amount (movement amount) of the medium and correcting the print position in accordance with the transport error.

  In the apparatus disclosed in Patent Document 1, in order to detect the amount of movement of the media, the surface of the media is imaged twice at different timings by the image sensor, and the image data obtained by capturing the first time is used. Extract a specific template image. The location of the template image in the second captured image is detected by a pattern matching technique, and the amount of media movement is calculated from the result.

  Patent Document 2 discloses a method for recording a detection pattern for detecting the position of a recording sheet in the margin of the recording sheet.

JP 2011-95162 A JP-A-3-42264

  According to the method of Patent Document 1, there is no feature point in the template image extracted from the first captured image depending on the type of media, and it is impossible to detect where the template image exists in the second image data by the pattern matching technique. There is drowning.

  The method of Patent Document 2 records a detection pattern separately from an actual image. However, in this method, a detection pattern is recorded in the margin. When there is no margin in the recording medium, it is necessary to record a pattern for detecting the conveyance amount of the recording medium in the recording area of the actual image. Since the deviation of the conveyance amount of the recording medium increases as the conveyance proceeds, it is necessary to detect the recording medium as frequently as possible and to correct the recording position as needed. Therefore, it is desirable to continue recording the detection pattern for the conveyance amount of the recording medium at regular intervals in the conveyance direction of the recording medium.

  On the other hand, in order to maintain the quality of recording, a method of detecting non-ejection of an ink ejection nozzle at a predetermined timing while recording an actual image on a recording medium is known. When this method is used, a discharge failure detection pattern is recorded during recording of an actual image, and this pattern is read by an image sensor such as a scanner to detect discharge failure.

  Here, if the non-discharge detection pattern and the pattern for detecting the conveyance amount of the recording medium overlap and are recorded, even if there is actually no ejection and no ink dots are recorded, that portion It will be recognized as if it were recorded. In such a case, non-ejection cannot be detected accurately.

  The present invention has been made in view of the above, and it is an object of the present invention to accurately detect non-ejection while recording a pattern for detecting a deviation in conveyance amount in association with image recording. To do.

The present invention relates to a first recording head for image recording comprising a nozzle array in which a plurality of nozzles for ejecting ink for recording an image on a recording medium, and the recording medium to the plurality of nozzles. The first recording head for recording on the recording medium a conveying means for conveying in a conveying direction that intersects the arrangement direction of the recording medium, and a conveying pattern for detecting the conveying amount of the recording medium by the conveying means. A second recording head, and a recording apparatus comprising:
The recording medium being transported by the transport means to the first recording head is read by a reading means, and a non-ejection state of the nozzle row is brought into a non-image area of the recording medium. A non-discharge detection pattern for detecting the nozzles being recorded, and causing the second recording head to record the transport pattern at predetermined intervals in an image area and a non-image area of the recording medium; and A recording apparatus comprising: control means for controlling timing for recording the conveyance pattern and the non-discharge detection pattern so that the conveyance pattern and the non-discharge detection pattern do not overlap.

  According to the present invention, it is possible to accurately detect a non-ejection while recording a pattern for suppressing detection of a deviation in the conveyance amount accompanying image recording.

1 is an overall external view of a printing apparatus according to an embodiment. It is a figure which shows the structure inside the printing part which concerns on embodiment. It is a block diagram of the sensor unit which concerns on embodiment. It is a figure for demonstrating a mode that the moving amount | distance of the medium which concerns on embodiment is detected. It is a figure which shows the state with which the undischarge detection pattern and the marking pattern have overlapped. It is a figure which shows the state of the recording of the undischarge detection pattern and marking pattern based on embodiment. FIG. 2 is a partial electrical configuration diagram of the printing apparatus according to the embodiment. It is a figure which shows the timing of the recording of the marking pattern and undischarge detection pattern which concern on embodiment. It is a figure which shows the mode of the recording of the marking pattern which concerns on embodiment. It is a figure which shows the timing of the recording of the marking pattern and undischarge detection pattern which concern on embodiment. FIG. 2 is a block diagram illustrating a control system for a printing apparatus.

(First embodiment)
Hereinafter, as an embodiment of the present invention, an embodiment of a printing apparatus (recording apparatus) using an inkjet method will be described. The printing apparatus according to this embodiment is a high-speed line printer that uses long and continuous sheets as media. For example, it is suitable for the field of printing a large number of sheets in a print laboratory or the like.

  FIG. 1 is an overall external view of a printing apparatus according to an embodiment. The printing apparatus 1000 includes a printing unit 1, a sheet supply unit 2, and a sheet winding unit 3. The sheet supply unit 2 holds the roll sheet 4 wound in a roll shape, and feeds the continuous sheet in the A direction (arrow) while pulling the continuous sheet from the roll, and supplies the continuous sheet to the print unit 1. The printing unit 1 sequentially prints a plurality of images on a continuous sheet. The printed continuous sheet is wound up as a roll sheet 5 by the sheet winding unit 3.

  FIG. 2 is a schematic diagram showing the internal configuration of the printing unit 1. 2A is a top view and FIG. 2B is a side view. The recording medium 8 is a continuous sheet, and the continuous sheet-like medium 8 supplied from the sheet supply unit 2 to the printing unit 1 is conveyed in the direction of arrow A in the printing unit. As a sheet conveyance mechanism in the printing unit, a main conveyance roller pair including a conveyance roller 11 and a pinch roller 12 that rotates following the conveyance roller 11 controls conveyance accuracy. On the downstream side of the print heads 17 to 20 for each color, four pairs of sub-conveying roller pairs including a conveying roller 13 and a pinch roller 14 that is driven to rotate are provided. Reference numerals 17 to 20 denote inkjet image recording print heads, which are a black color print head 17, a cyan color print head 18, a magenta color print head 19, and a yellow color print head 20. is there. Each head is a line type print head having a nozzle row in which inkjet nozzles are arranged over a range that covers the maximum width (in the B direction) of the medium that is assumed to be used. The nozzles for ink ejection are formed so as to cover the entire arrangement direction (B direction) of the nozzles. The B direction intersects with the A direction and is substantially orthogonal. These image recording heads record images in accordance with image data desired by the user. As the inkjet method, a method using a heating element, a method using a piezo element, a method using an electrostatic element, a method using a MEMS element, or the like can be adopted. The number of colors and the number of print heads are not limited to four, and may be larger or smaller. An ink tube is connected to each print head, and ink is supplied from an ink tank (not shown). Each print head may be a unit integrated with an ink tank for storing the corresponding color ink. Each print head is integrally held by the head holder 10. A sensor unit 201 images a marking pattern as a transport pattern for detecting the moving amount or moving speed of the medium 8 recorded by the marking head 100. Based on the image data obtained by this, it is used for detecting the moving amount or moving speed of the medium 8 by pattern matching. The marking head 100 is an ink jet print head and has a marking nozzle portion 101 for discharging ink. Further, the marking head 100 and the sensor unit 201 are arranged upstream of each color print head for recording an actual image and substantially at the center in the media width direction. With this arrangement, it is possible to cope with borderless full-surface printing with no margins, hardly affected by the mist of each color ink-jet head, and an average conveyance amount can be detected with respect to minute meandering and minute skew of the medium. In such a transport pass, one-pass printing is performed from a head fixed in the order of black, cyan, magenta, and yellow on a recording medium that moves relative to the head by being transported in the A direction. go. Reference numeral 40 denotes an image sensor that reads undischarge detection patterns recorded by the heads 17 to 20 when non-discharge detection is performed. Reference numeral 50 denotes an encoder fixed to the shaft of the conveyance roller, and is used for generating a print drive timing described later. The marking head 100 is also fixed to the head holder 7.

  3A and 3B are configuration diagrams of the sensor unit 201. FIG. 3A is a view seen from above, and FIG. 3B is a cross-sectional view seen from the side. The sensor unit 201 mainly includes a light emitting unit, a light receiving unit, and an image processing unit, and these are integrated as a unit. The light source 203 is a light emitting element such as an LED. Light emitted from the light source 203 is guided to the light guide 202 and illuminates the surface of the medium 8 from an oblique direction. The image of the illumination area on the medium 8 is formed on the image sensor 205 by the lens 206. The transparent protective cover 204 prevents dirt from adhering to the lens 206 due to ink mist or the like entering from the medium 8 side. An image of the media including the marking pattern recorded by the marking head 100 is acquired by the image sensor 205. The imaging signal of the image sensor 205 is A / D converted and sent to the image processing unit 207. The image processing unit 207 detects a moving amount (carrying amount) of the media by comparing a plurality of image data obtained by performing imaging a plurality of times with the movement of the media by image processing including a pattern matching process. To do. The media movement information thus obtained is fed back to the control unit 6 described later.

  FIG. 11 is a block diagram illustrating a detailed configuration of a control system of the printing apparatus 1000. A control unit 6 (range surrounded by a broken line) provided in the printing apparatus includes a CPU 105, a ROM 106, a RAM 107, an engine control unit 111, an individual unit control unit 112, and an image processing unit 113. The CPU 105 (central processing unit) controls the operation of each unit of the recording apparatus in an integrated manner. The ROM 106 stores programs to be executed by the CPU 105 and fixed data necessary for various operations of the recording apparatus. The RAM 107 is used as a work area for the CPU 105, used as a temporary storage area for various received data, and stores various setting data. The operation unit 110 is an input / output interface with a user.

  A dedicated processing unit is provided for units that require relatively high-speed data processing. The image processing unit 113 performs image processing of recording data handled by the recording apparatus. The color space (for example, YCbCr) of the input image data is converted into a standard RGB color space (for example, sRGB). Further, color separation processing is performed for converting the RGB image data into C, M, Y, and K ink data used in the printer of this embodiment. Further, various image processing such as resolution conversion, image analysis, and image correction is performed on the ink color image data as necessary. Then, quantization (binarization) is performed on multi-value (for example, 256 values) image data of each of the C, M, Y, and K inks obtained as described above, and C, M, Y, Print data (binary data) for each of the K inks is generated.

  The recording data obtained by the above image processing is stored in the RAM 107. This recording data is sent from the print heads 17 to 20. Further, the image processing unit 113 performs processing such as analysis of photographing data obtained from the image sensor 40 and feedback of the analysis result to the engine control unit 111.

  The engine control unit 111 performs drive control of the print head 17-20 and the marking recording drive unit 505 of the print unit 1 according to the recording data based on a control command received from the CPU 105 or the like. The engine control unit 111 further controls the transport mechanism of each unit in the recording apparatus. The individual unit control unit 112 is a sub-controller for individually controlling each unit of the sheet supply unit 2 and the sheet winding unit 3.

  The individual unit control unit 112 controls the operation of each unit based on a command from the CPU 105. The external interface 109 is an interface (I / F) for connecting the control unit 6 to the host device 108, and is a local I / F or a network I / F. The above components are connected by a system bus.

  The host device 108 is a device serving as a supply source of image data for causing the recording device to perform recording. The host device 108 may be a general purpose or dedicated computer.

  Control for detecting the amount of movement of the medium from the image data obtained by the imaging of the sensor unit 201 will be described with reference to FIG. The medium 8 is conveyed in the direction A of FIG. 4A, FIG. 4A is a state before the medium is moved, FIG. 4B is a state after a predetermined time from the medium, and after the medium is moved. It is. In FIG. 4A, 100 is a marking head for printing a marking pattern, and 311 is a nozzle that records a marking pattern for detecting the amount of movement in the marking head 100. Reference numerals 301, 312, 313, 314, and 315 are marking patterns recorded by the nozzle 311 of the marking head. An area 302 indicated by diagonal lines represents an image area captured by the sensor unit 201. Ink corresponding to the marking patterns 301, 312, 313, 314, and 315 is ejected from the nozzles of the marking head at regular intervals. Although the marking pattern is schematically represented by one dot, this marking pattern is a pattern of a specific pattern recorded by a predetermined number of nozzles in addition to one recorded by one dot. It may be.

  At this time, an area 300 surrounded by a square in FIG. 4A represents a template image area extracted from the imaging area 302 by the image sensor. In FIG. 4B, 305 represents a state after the marking pattern 301 has been moved until the second imaging, and an area 407 indicated by hatching in FIG. 4B is the same as FIG. 4A. Similarly, it represents an image area imaged by the image sensor. An area 308 surrounded by a square in FIG. 4B represents a search area for detecting the template image area 300 extracted in the first imaging in the second imaging area 307. The search area 308 is wider than the template image area, and it is detected by pattern matching at which pixel position in the search area the same image as the template image exists. From the result, the image processing unit 207 calculates the moving amount of the medium. For example, if a detection pattern should originally exist at the position 309 in FIG. 4B but it can be detected by pattern matching that a detection pattern exists at the position 305, the difference in distance is detected. This is the amount of media movement. Reference numeral 306 is a template image for calculating the next movement amount, and the movement amount of the media is calculated in real time by repeating the same processing. The calculated movement amount is fed back to the control unit 6 each time, and the control unit 6 uses the engine control unit 111 based on the movement amount to determine the individual ejection timings of the print heads 17-20 and between the print heads. Control relative discharge timing.

  Here, consider a case where the non-discharge detection pattern for detecting non-discharge of the nozzles of the print head 17-20 overlaps with the marking pattern. In FIG. 5, the medium 8 is conveyed in the direction A and ink is ejected from the marking head 100 to form dot images of the marking patterns 420 and 430. Further, the non-discharge detection pattern 410 is recorded by the black print head 17 of the four color print heads. The undischarge detection pattern 410 is recorded by discharging ink from the nozzles 401 of the black color head 17. The recording location is a non-image area where the actual image is not formed, which is different from the image forming area where the actual image of the medium 8 is formed. Here, it is assumed that some of the nozzles 402 of the black color head 17 are in a non-ejection state. In the undischarge detection pattern 410, no recording should be made at a position that coincides with the position of the nozzle 402 in the B direction. Even in the image data picked up by the image sensor 40, the image is missing. Non-ejection should be detected. However, since the marking pattern 430 overlaps the discharge failure detection pattern 410, the detection by the image sensor 40 detects as if the nozzles 402 are performing normal ejection.

  FIG. 6 is a diagram illustrating a state in which the timing for recording the marking pattern is controlled so that the discharge failure detection pattern and the marking pattern do not overlap with each other according to the present embodiment. The medium 8 is transported in the transport direction A. In the same manner as described with reference to FIG. 5, the discharge failure detection pattern 410 is formed in the non-image area. On the other hand, the marking pattern 420 is recorded in both the image forming area and the non-image area.

  In order to avoid the marking pattern 450 in FIG. 6 from overlapping the discharge failure detection pattern 410, the discharge is performed with a delay of time T. Thereby, the image omission 440 of the discharge failure detection pattern 410 is recognized by the image sensor, and it becomes possible to detect the discharge failure state of the nozzle 402. Based on this detection result, the image processing unit 113 performs processing for complementing an image such as allocating data used for recording of the nozzle 402 to another nozzle, for example, an adjacent nozzle.

  Next, with reference to FIG. 7 and FIG. 8, the control for recording the marking pattern as described in FIG. 6 will be described. FIG. 7 is a schematic diagram for explaining details of the electrical configuration of the recording head controller 501 that forms part of the engine control unit 111. The recording head controller 501 includes an image recording timing generation unit 502, an image recording driving unit 503 for actual image recording, and a marking recording driving unit 505 for marking pattern recording. The output side of the image recording drive unit 503 is connected to the corresponding color print head 17-20. The image recording timing generation unit 502 is a module that manages image information to be recorded and position information on the medium 8 on which the image is recorded.

  FIG. 8 shows a timing chart of signals output from the recording head controller 501. The image recording drive unit 503 indicates the image recording timing to each print head based on the position information of the image recorded on the medium from the image recording timing generation unit 502 and the position information of the medium being conveyed from the encoder unit 50. Send a signal. This image recording timing is a timing adjusted by a delay from a reference position in accordance with image position information and media position information. In addition, the image recording timing generation unit 502 outputs a signal indicating the timing corresponding to the recording at the position of the discharge failure detection pattern for determining whether or not the marking pattern overlaps the discharge failure detection pattern. To the unit 505. Since the king head is on the upstream side of the print head, the delay of this signal from the reference position is less than the delay of the signal transmitted to each print head in accordance with the ejection timing of the marking head.

  The marking recording drive unit 505 uniquely generates a signal indicating the recording timing of the marking pattern based on the data dedicated to the marking pattern, and outputs a discharge timing signal to the marking head. Also, a signal indicating position information of the discharge failure detection pattern is received from the image recording timing generation unit 502, and whether or not the timing corresponding to the discharge failure detection pattern indicated by this signal overlaps with the discharge timing of the marking print pattern. to decide. When the timing signal corresponding to the undischarge detection pattern and the discharge timing of the marking print pattern overlap, the printing timing of the marking pattern delayed by time T is generated. As for the deviation of the time T, it is sufficient to shift the deviation corresponding to the width of the undischarge detection pattern. Therefore, it is preferable to make the deviation as short as possible in order to shorten the detection interval of the movement amount of the medium. As a result, the ejection timing of the marking pattern is corrected so as to shift, the overlap between the ejection failure detection pattern and the signal for recording the corrected marking pattern is avoided, and the ejection failure detection can be performed accurately. .

(Second Embodiment)
The second embodiment will be described with reference to FIG. FIG. 9 shows a state where control is performed so that the discharge failure detection pattern and the marking pattern do not overlap. The medium 8 is transported in the transport direction A. As shown in FIG. 9, image information indicating an image whose position is determined so that the marking pattern 460 does not overlap with the position W corresponding to the undischarge detection pattern 410 is generated. It becomes possible to detect the undischarge part 470.

  The recording head controller 501 is the same as that of the first embodiment, but the marking information is included in the position information in the image recording timing generation unit 502, and the marking (job) and the undischarge detection pattern do not overlap. Control as follows.

  FIG. 10 shows a timing chart of signals output from the recording head controller 501 of the ink jet recording apparatus according to this embodiment. In the present embodiment, the image recording timing generation unit 502 generates print position information including information on the discharge failure detection pattern and the marking pattern. The marking recording drive unit 505 and the image recording drive unit 503 transmit drive timings according to the print image information from the image recording timing generation unit and the position information from the encoder. Therefore, the discharge failure detection pattern and the marking pattern do not overlap on the recording medium, and the discharge failure nozzle of the print head can be detected.

(Other embodiments)
Further, in the first embodiment described above, the form in which the timing of generating the printing timing of the marking pattern is delayed is shown. However, in the image recording timing generation unit 502, it is possible to detect the marking pattern printing timing and take control to delay the recording timing of the undischarge detection pattern 4 so that the undischarge detection pattern and the marking pattern do not overlap. It is.

Claims (10)

A first recording head for image recording comprising a nozzle array in which a plurality of nozzles for ejecting ink for recording an image on a recording medium are arranged; and an arrangement direction of the plurality of nozzles in the recording medium A conveying unit that conveys in the intersecting conveying direction, and a first recording head different from the first recording head for recording on the recording medium a conveyance pattern for detecting the conveyance amount of the recording medium by the conveying unit. A recording apparatus having two recording heads,
The recording medium being transported by the transport means to the first recording head is read by a reading means, and a non-ejection state of the nozzle row is brought into a non-image area of the recording medium. A non-discharge detection pattern for detecting the nozzles being recorded, and causing the second recording head to record the transport pattern at predetermined intervals in an image area and a non-image area of the recording medium; and A recording apparatus comprising: control means for controlling timing for recording the transport pattern and the undischarge detection pattern so that the transport pattern and the undischarge detection pattern do not overlap.   The control means acquires a signal indicating a position where the discharge failure detection pattern is recorded on a recording medium, and controls the timing at which the second recording head records the transport pattern based on the acquired signal. The recording apparatus according to claim 1.   The control unit generates a first signal indicating a timing for recording the conveyance pattern, and records the conveyance pattern when a recording timing of the discharge failure detection pattern coincides with a timing for recording the conveyance pattern. The recording apparatus according to claim 2, wherein the second signal is generated by shifting the timing of the recording. Generating means for generating position information indicating the position of the undischarge detection pattern and the image recorded on the recording medium;
The control unit controls the timing at which the first recording head records the image and the undischarge detection pattern based on the position information generated by the generation unit, and the position generated by the generation unit The timing at which the second recording head records the transport pattern is controlled based on a signal indicating a position where the undischarge detection pattern is recorded on a recording medium based on information. 3. The recording device according to 3.   The recording apparatus according to claim 4, wherein the position information generated by the generation unit does not include information indicating the position of the transport pattern on the recording medium.   The position information generated by the generation unit includes information indicating the position of the transport pattern on the recording medium, and the position information does not overlap the position where the discharge failure detection pattern is recorded and the transport pattern. The recording apparatus according to claim 4, wherein positions of the discharge failure detection pattern and the conveyance pattern are determined.   The recording apparatus according to claim 1, wherein the second recording head is provided upstream of the first recording head in the transport direction.   8. The apparatus according to claim 1, further comprising: a reading unit that reads the transport pattern; and an adjusting unit that adjusts a position where the recording head records the image based on a reading result of the reading unit. The recording apparatus according to any one of the above.   The recording apparatus according to claim 1, wherein the reading unit that reads the conveyance pattern is provided upstream of the first recording head in the conveyance direction. An array of the plurality of nozzles is formed by using the first recording head for image recording including a nozzle row in which a plurality of nozzles for ejecting ink are arranged to record an image on the recording medium. Recording is performed while transporting in a transport direction that intersects the direction, and the first recording head is used to perform a non-ejection state in the nozzle row in the non-image area of the transported recording medium. In a recording method for recording a discharge failure detection pattern for detecting a nozzle,
A conveyance pattern for detecting a conveyance amount of the recording medium by a second recording head different from the first recording head is recorded in an image area and a non-image area of the recording medium at a predetermined interval; and The first recording head records the undischarge detection pattern and the second recording head records the transport pattern so that the undischarge detection pattern and the transport pattern do not overlap. Recording method.

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