JP2006167956A - Recorder and recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer in which head shading correction is realized with high speed and high precision. <P>SOLUTION: The recorder having a function for detecting unevenness in density of a recording pattern formed by a recording head arranged with a plurality of recording elements and correcting the density data of each recording element comprises a means for printing an uneven density detection pattern by using the plurality of recording elements, a reader for reading density data from the uneven density detection pattern, a memory for storing the density data thus read out, measuring point data, and positional information data of each recording element, a means for operating the density data at the same position as that being taken in by a different pixel of a sensor arranged in a reading means, and a means for making the density data correspond to the positional information of each element. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an image forming apparatus that corrects density unevenness caused by variations in the discharge amount and the like for each nozzle in a recording head. In particular, the present invention is effective for an image forming apparatus using an inkjet recording head in which a plurality of nozzles are arranged, and a color image recording apparatus using a plurality of recording heads.

  With the widespread use of information processing equipment such as copying machines, word processors, computers, and communication equipment, digital image recording is performed using a recording head using an ink jet method, a thermal transfer method, or the like as an image forming device (recording device) for such devices. Devices that perform the above are rapidly spreading.

  In such a recording apparatus, in order to improve the recording speed, a recording head in which a plurality of recording elements are integrated is generally used.

  For example, in an inkjet recording head, a so-called multi-nozzle head in which a plurality of ink discharge ports and liquid paths are integrated is generally used, and a plurality of heaters are integrated in a thermal transfer type and thermal type thermal head, and mechanical energy is also increased. Even in the -type piezo head, a plurality of ejection mechanisms are generally integrated.

  In such a recording head, it is difficult to uniformly manufacture the characteristics of the plurality of recording elements due to variations in characteristics due to the manufacturing process, characteristics variations in the head constituent materials, and the like. As a result, in such a recording head, the characteristics of the respective recording elements vary to some extent. For example, the ink jet recording head has variations in the shapes of the discharge ports and the liquid paths, and the thermal head has variations in the shape and resistance of the heater.

  Further, in addition to the cause of the limitation of the manufacturing technique, the characteristics between the recording elements of the recording head also vary due to aging.

  Such non-uniformity of characteristics between the recording elements in the recording head appears as non-uniformity in the size and density of dots recorded by each recording element, resulting in uneven density in the recorded image.

  Such a variation in characteristics of each recording element in the recording head (for example, uneven ink discharge amount in an ink jet recording head) significantly impairs the quality of a recorded image. Conventionally, attempts have been made to correct such a variation in characteristics. Has been made.

  As such an attempt, a recording apparatus having the following configuration has been proposed. That is, a recording apparatus has been proposed in which a recording pattern reading unit is provided in a recording apparatus, density unevenness in a recording element array range is periodically read, and density unevenness correction data is created based on the read density unevenness data. Yes.

  In a recording apparatus for recording using a recording head having a plurality of recording elements, the density of the pattern recorded by the recording head is read in correspondence with the recording elements, and image data according to the density obtained corresponding to each recording element A technique for reducing density unevenness by correcting the above is known (see, for example, Patent Document 1). A technique for correcting this density unevenness is generally called head shading.

  Such a method for correcting density unevenness will be described by taking an ink jet recording apparatus as an example of the recording apparatus and correcting the density unevenness.

  Here, a so-called BJ-type head that ejects ink droplets with bubble generation pressure will be described, but the same can be applied to a so-called piezo-type head that ejects droplets with mechanical vibration energy. is there.

  The recording head of this ink jet recording apparatus, for example, forms bubbles in the ink in the discharge ports by the heat generated by the thermoelectric conversion elements mounted inside the plurality of discharge ports, and discharges ink droplets with this bubble generation pressure. In the case of a so-called BJ type head, the head is configured to be able to scan, for example, a range corresponding to the short side length (297 mm) of an A3 size recording medium. This head has 128 ejection openings arranged at a density of 400 dpi (dots per inch) in a direction perpendicular to the scanning direction. In the case of color, four heads having this configuration are used, and these four heads are a cyan head, a magenta head, a yellow head, and a black head.

  FIG. 12 is a diagram illustrating an example in which detection patterns with different conditions are arranged on a recording medium for each head of a plurality of colors.

  In order to correct the discharge unevenness (density unevenness) for each ink discharge port of the recording head, for each ink discharge port, each ink discharge port and the recording density data read by the reading system are correctly set. It is a premise that they are associated.

  In the conventional example, first, each ejection port of the recording head is driven by a predetermined uniform recording signal, and a test pattern 2 for detecting density unevenness is formed on the recording medium 1 as shown in FIG.

  The test pattern 2 is formed for each color, for example, as shown in FIG.

  FIG. 13 is an explanatory diagram of a conventional example.

  When forming the test pattern 2, as shown on the left side of FIG. 13, the printing direction is from left to right by the head in which a plurality of discharge ports are arranged in a line, and the three lines of the upper stage 2a, the middle stage 2b, and the lower stage 2c Is printed to form a test pattern 2.

  The formation method of the pattern 2 is called irregular three-line printing. For example, when there are 128 discharge ports, first, the ink is discharged from the 96th to the final 128th discharge ports, so that the first. 1 line 2a is printed. Next, the second line 2b is printed by ejecting ink from all the first to 128th ejection openings. The last third line 2c is printed by causing ink to be ejected from the 32nd ejection port from the most advanced 1st ejection port.

  FIG. 14 is a schematic diagram illustrating a configuration and operation of a detection pattern, a reading unit, and a scanning unit thereof in a conventional example.

  A reading mechanism (charge coupled device, reading sensor) 210 is configured on a carriage or the like that moves the head 20 in the main scanning direction, and the reading mechanism 210 is arranged in a direction orthogonal to the head nozzle row direction. Detection is performed by moving on the detection pattern in the sub-scanning direction.

  At this time, the movement in the sub-scanning direction is driven by a mechanism that moves the reading mechanism in the sub-scanning direction, as indicated by A. Alternatively, as indicated by B, the reading mechanism 210 may be stopped at an arbitrary position, and the recording medium 1 may be moved in the sub-scanning direction by the recording medium transport mechanism.

  FIG. 15 is a diagram showing an outline of the reading mechanism 210.

  In FIG. 15, the reading mechanism 210 includes a light source 61 for illuminating a recording medium, and a lens 62 that forms an image on a photoelectric conversion element 63 such as a CCD or CMOS sensor. The row information of the image that goes straight in the main scanning direction is read with the number of pixels corresponding to the CCD or the like.

  After the image is read by a predetermined width, it is driven in the main scanning reverse direction. As a result, the reading mechanism 210 returns to the initial position. Next, the carriage is driven in the main scanning direction, the reading mechanism 210 is moved to the next pattern, and the entire image is read by repeating the above measurement procedure.

  Next, as shown in FIG. 13, a reading method will be described by taking a test pattern of a certain color formed as described above as an example.

  As shown on the left side of FIG. 13, the test pattern 2 of a certain color is read by the image reading system in the arrow Y direction from the reading start position S to the reading end position F, and the read density distribution data is read in the order of reading. It is temporarily stored in the memory in the device.

  In the conventional recording apparatus, the recording density of the ink jet recording system and the resolution of the image reading mechanism 210 are the same, for example, 400 dpi (dot per inch). Therefore, a dot of ink discharged from each ink discharge port corresponds to one pixel of the reading system.

  Further, if the density data on the memory is expressed by 256 gradations, one discharge port can be associated with one byte area on the memory, and the print density by the discharge port can be expressed. This is because, as is well known, one byte is composed of binary 8 bits, and the number of combinations is 28 = 256. Accordingly, if the threshold value DTH is appropriately set, the section (number of bytes) of density data exceeding the threshold value coincides with the ejection section in the test pattern reading direction.

  The section of X1 to X2 in the upper graph shown in FIG. 13 is the section of the test pattern. Since X1 and X2 are obtained as address information on the memory, the storage addresses of the density data of the first discharge port to the 128th discharge port are obtained by address calculation, and the density unevenness correction amount is calculated from this density data. can do.

  By the way, the reading sensor has been proposed in the center of the line-shaped configuration, but in order to measure a plurality of discharge amounts with high accuracy by the discharge amount measuring method using this sensor, the measurement time is measured, Alternatively, it is necessary to configure a detection pattern width corresponding to the movement width of the sensor for measuring the discharge amount data necessary for the measurement.

Therefore, in the above conventional example, a method of measuring at a low scanning speed or increasing the number of times of measurement is used, and there is a concern that the time required for detection may be prolonged.
JP-A-3-295675

  In recent years, with the progress of high-definition due to smaller ink droplets that meet the demand for higher image quality, discharge amount correction to maintain high image quality is increasingly important. In addition, in order to cope with high-speed printing, a printer having a plurality of heads for the same color has also been proposed, and the number of heads configured in one printer is increased. There is a concern that the time for detecting this may be further prolonged.

The present invention provides an efficient density detection method when a two-dimensional matrix sensor is used for the density reading mechanism, and a method for detecting the density of each printing element and the occurrence of non-ejection by using a pattern configuration necessary for this. Accordingly, an object of the present invention is to provide a printing apparatus that can realize head shading correction at high speed and high accuracy.

The present invention provides a recording apparatus having a recording density unevenness correction function for detecting density unevenness of a recording pattern formed by a recording head in which a plurality of recording elements are arranged and correcting density data of each recording element. A means for printing a detection pattern using the plurality of recording elements, a density reading device for reading density data from the density unevenness detection pattern, the read density data, measurement position data, and each recording element Correspondence between memory for storing positional information data, arithmetic processing means for arithmetically processing density data at the same position captured by different pixels of the sensor configured in the reading means, and the density data and positional information of each element It is a recording apparatus characterized by having the correspondence means which takes.

According to the present invention, even when the number of print heads increases, the density detection or non-discharge state of each recording element of the head can be detected with high accuracy, and measurement can be performed at high speed. The position can be accurately and quickly executed. Therefore, there is an effect that high-speed printing can be realized while maintaining the head shading correction performance.

  The best mode for carrying out the invention is the following embodiment.

  FIG. 1 is a diagram illustrating a configuration example of an inkjet head cartridge 21 in an inkjet recording apparatus P1 that is Embodiment 1 of the present invention.

  The ink jet head cartridge 21 in the ink jet recording apparatus P <b> 1 includes an ink tank 10 and a recording head 20.

  The recording head 20 is an ink jet head (recording head) that uses air bubbles generated by thermal energy and discharges ink onto recording paper, or a head that discharges by mechanical energy, and is integrally attached to the ink tank 10. Yes.

  The integrated recording head 20 and ink tank 10 constitute an ink jet head cartridge 21, and this cartridge 21 is detachably attached to the recording apparatus P1.

  In the inkjet head cartridge 21, the tip of the inkjet recording head 20 slightly protrudes from the front surface of the ink tank 10.

  This cartridge 21 is of a replaceable type, and is mounted on a carriage 16 mounted on an ink jet recording apparatus main body driving mechanism (a driving mechanism including a driving motor 17, a driving belt 18, and guide shafts 19A and 19B) described later. Removably fixed and supported.

  The ink tank 10 stores ink to be supplied to the ink jet recording head 20, and includes an ink absorber, a container into which the ink absorber is inserted, and a lid member (all not shown) for sealing the ink absorber. ing. The ink tank 10 is filled with ink, and the ink is sequentially supplied to the recording head 20 side in accordance with the ejection of ink from the recording head 20.

  The ink jet head cartridge 21 is detachably mounted on a carriage of the ink jet recording apparatus driving mechanism by a predetermined method, and controls the relative movement between the carriage and the recording member by inputting a predetermined recording signal. The recorded image is formed.

  FIG. 2 is an external perspective view showing an example of an ink jet recording apparatus P1 provided with a mechanism for the head shading process.

  The ink jet recording apparatus P1 includes a carriage 16, a drive motor 17, a drive belt 18, guide shafts 19A and 19B, a motor 22, a reading mechanism 210, a transmission mechanism 23, a head recovery device 26, and a cap portion 26A. And a blade 31 and a blade holding member 31A.

  The carriage 16 is a carriage 16 that holds the recording head 20, and is connected to a part of a driving belt 18 that transmits a driving force of the driving motor 17, and two guide shafts 19 </ b> A and 19 </ b> B that are arranged in parallel to each other. Is slidably attached. As a result, the recording head 20 can freely reciprocate over the entire width of the recording paper, and an image corresponding to the received data is recorded on the recording paper during the reciprocating movement. Each time one scan (main scan) for recording by the recording head 20 is completed, the recording paper is conveyed by a predetermined amount in the direction orthogonal to the main scan (sub-scan is performed).

  Adjacent to the carriage 16, a reading mechanism 210 by the two-dimensional matrix sensor 1004 shown in FIG. Similar to the head, the reading mechanism 210 can be driven in the main scanning direction. As an example, in FIG. 2, the head is adjacent to the head in the main scanning direction, but the position is not limited to the position in FIG.

  The head recovery device 26 is disposed at one end of the moving path of the recording head 20, for example, at a position facing the home position. The head recovery device 26 is driven by the motor 22 via the transmission mechanism 23 to perform capping of the recording head 20.

  The head recovery device 26 has a cap portion 26A, and the cap portion 26A is fitted to the recording head 20, and suction operation (for example, a suction pump) provided in the head recovery device 26 is performed (a suction operation). (Suction recovery). By this suction operation, the ink is forcibly discharged from each ejection port of the recording head 20, whereby thickened ink existing in each ejection port of the recording head 20, dust around each ejection port, etc. Deposits can be removed, and a discharge recovery process is realized.

  Further, when the recording operation is not performed for a relatively long period of time such as after the recording is finished, the recording head 20 is protected from drying, dust adhesion, and the like by capping the recording head 20 using the cap portion 26A. can do. Such a discharge recovery process is executed when the power is turned on, when the recording head is replaced, or when the recording operation is not performed for a certain period of time.

  The blade 31 is a blade as a wiping member that is disposed on the side surface of the head recovery device 26 and is formed of silicon rubber. The blade 31 is held in the form of a cantilever by the blade holding member 31 </ b> A and is operated by the motor 22 and the transmission mechanism 23 in the same manner as the head recovery device 26, and slidably contacts the ejection surface of the recording head 20. Therefore, the blade 31 is moved by projecting the blade 31 into the moving path of the recording head 20 at an appropriate timing during the recording operation of the recording head 20 or after the ejection recovery process using the head recovery device 26. By rubbing the ejection surface of the recording head 20 in the inside, it is possible to wipe off deposits such as condensation, wetting, or dust adhering to the ejection surface.

  For the sake of simplicity, FIG. 1 shows a single-color recording apparatus with one inkjet head cartridge 21 attached. However, in the case of a multi-color recording apparatus, cyan, magenta, and yellow are provided on the carriage 16. Basically, the structure is the same except that four inkjet head cartridges of black and black are attached.

  FIG. 11 is a diagram illustrating a block configuration example of the reading system and the recording system of the inkjet recording apparatus P1.

  FIG. 11 mainly shows the image processing unit 200. The recording head 20, the head driver 110, and the print / temperature adjustment control unit 120 in FIG. 11 are the recording unit 100.

  The head driver 110 supplies a signal for heating and adjusting the recording head 20 to a constant temperature and an ejection pulse for ejecting ink to the heating medium in each ejection port.

  The print / temperature adjustment control unit 120 obtains temperature information from a temperature sensor (not shown) in the recording head 20 and outputs a temperature adjustment signal output by the head driver 110 so as to maintain the recording head 20 at a predetermined temperature. And the pulse width of the ejection pulse are adjusted.

  The control unit 120 controls the printing section for each printing color.

  The image data input to the recording unit 100 is a binary signal indicating whether or not ink is ejected to each ink ejection port. When binarized image data is input to the head driver 110 controlled by the printing / temperature adjustment control unit 120, ink is ejected from each ejection port of the corresponding recording head 20.

  Further, it is possible to eject ink from the ejection port without inputting image data, and the control unit 120 applies a heating pulse used for temperature adjustment from the head driver 110 to a specific ejection port at a normal temperature. By applying for a longer time than at the time of adjustment, ink is ejected from the ejection port.

  The ejection port position detection test pattern (hereinafter referred to as “chart”) is printed using this ejection method. That is, ink is ejected only from a specific ejection port of the recording head 20 by the drive signal of the printing / temperature adjustment control unit 120 of the recording unit 100, and is shown on the right side of each density unevenness detection pattern A as shown in FIG. A linear discharge port position detection chart B is printed.

  In FIG. 11, the configuration excluding the recording unit 100 particularly shows the image processing unit 200.

  By inputting a fixed value (80H) 250 of cyan, magenta, yellow, and black to the γ conversion unit 270 of the image processing unit 200 shown in FIG. 11, the density unevenness detection pattern A is printed, and is used as a halftone pattern. Record.

  Next, a density detection method using a two-dimensional matrix sensor for detecting density unevenness will be described.

  FIG. 3 is an explanatory diagram of a density detection method using a two-dimensional matrix sensor for detecting density unevenness.

  The other parts relating to the head shading process other than the correspondence to the density detection are not the main part of the present invention but are also known techniques, and thus the description thereof is omitted.

  The recording medium 1 is conveyed in the sub scanning direction 1006. In the recording head 20, the array of recording elements is arranged in parallel with the sub-scanning direction 1006. The recording head 20 is supported by the head driving carriage 16 and is driven in the main scanning direction 1005. The head during conveyance of the carriage 16 prints the head recording element based on the image data while synchronizing with the head position signal being driven.

  The measurement pattern 101 constitutes a range (interval) 1112 in which the density of each recording element 1 can be determined in accordance with the sensor resolution that has been confirmed in advance. A position detection pattern 1001 is formed around the measurement pattern 101. A two-dimensional matrix sensor 1004 configured on the carriage 16 adjacent to the recording head 20 is driven in the main scanning direction 1005 to perform pattern measurement.

  At the time of pattern measurement, the recording medium 1 is driven in the sub-scanning direction 1006 to a position where the position detection pattern 1001 and the measurement pattern 101 can be simultaneously measured in the effective pixel range of the two-dimensional matrix sensor 1004 according to predetermined conditions. deep. The two-dimensional sensor 1004 arbitrarily transports the recording medium 1 in the sub-scanning direction 1006 after measurement while driving the main scanning line in both directions. The above operation is repeated according to the measurement conditions.

  Next, the measurement state of the two-dimensional matrix sensor will be described.

  FIG. 4 is an enlarged view showing a measurement state of the two-dimensional matrix sensor.

  A certain measurement pattern 101 is measured by the two-dimensional matrix sensor 1004 while moving in the main scanning direction 1005. Here, paying attention to the pattern row A1116 at a certain measurement position on the measurement pattern 101, measurement is started from the measurement start position as shown in FIG. 4 (1), and scanning is started as shown in FIG. 4 (2). At the measurement point of the later arbitrary measurement time T, the measurement pattern A 1116 is detected in the pixel column (N−1) 0 column of the two-dimensional matrix sensor 1004.

  Further, by the subsequent scanning, the measurement pattern A 1116 is detected by the sensor pixel array 20 at the measurement point of the measurement time T + n. At this time, the position detection pattern is simultaneously detected in 00 rows of the two-dimensional matrix sensor effective pixels, the position detection pattern 1123 at the position of the pattern A 1116 is detected, and the pixel column determines the pixel at the detection position at each measurement time. can do. From this, measurement is performed in a shorter measurement time, and data of a plurality of different pixels in the two-dimensional sensor pixel is acquired. From this data, a data string in which the pattern positions of the measurement pattern 101 are combined is subjected to arithmetic processing, whereby the discharge amount measurement of the pattern A 1116 can acquire measurement accuracy data similar to the conventional one.

  FIG. 5 is an enlarged view showing the measurement state of the two-dimensional matrix sensor.

  In addition, the position detection pattern 1001 shown in FIG. 5 has an interval 1134 periods greater than or equal to the measurement effective pixel width 1135 of the two-dimensional matrix sensor 1004, and a pattern in which each position can be recognized independently within this range.

  As shown in FIG. 5B, the position detection pattern is read when the scanning position of the sensor moves to position A1130, position B1131, and position C1132 on the position detection pattern. Since the position detection pattern is a pattern that can independently recognize the position within a predetermined range as described above, the sensor position information obtained by reading the position detection pattern at each of the positions A, B, and C is: The positions A, B, and C are not the same. Therefore, for example, even if data is acquired irregularly, the position of the measurement data can be determined, and therefore the entire position can be recognized.

  Further, since it is sufficient to form a pattern by repeating the period of effective pixels, for example, even if the density detection width is increased, the position detection pattern is not complicated.

  Next, an outline of the head shading sequence will be described.

  FIG. 6 is a flowchart showing an outline of the head shading sequence.

  In S1, the detection sensor (two-dimensional matrix sensor) 1004 is calibrated. A calibration pattern is measured in advance, and variations between pixels are corrected from this data. However, step S1 is executed at the initial stage of the detection sensor 1004 (charge coupled device 210 shown in FIG. 11, read sensor 210 shown in FIG. 13, read mechanism 210 shown in FIG. You may or may not go.

  In S2, the pattern configuration is printed. In S3, the printed pattern is read, the density data is calculated, and the density data is associated with the discharge port by the correspondence and calculation between each measurement point and the density data.

  In S4, unevenness correction data (HS data) is calculated, and the head shading process ends. Thereafter, the image information drive signal is corrected based on the calculated HS data, and an image without density unevenness is recorded.

  Next, details of the head shading process will be described.

  FIG. 7 is a flowchart showing the calibration operation of the detection sensor.

  In S11, a reference pattern is selected, and each pixel resolution of the sensor and a pattern corresponding to the print pattern are prepared. In S12, the same pattern is designated one or more times and a plurality of measurement times are designated.

  In S13, the reference pattern is measured by a detection sensor, and detection sensitivity of each pixel, light amount adjustment, and density variation between pixels are detected. In S14, a detection result is determined and it is determined whether or not remeasurement is performed. From the measurement results obtained a plurality of times, a measurement condition and a correction value for each pixel are calculated.

  In S15, if the discharge pattern for each printing element cannot be detected as a result of performing re-measurement for an arbitrary upper limit number of times, the conditions of the density unevenness measurement reference pattern are optimized. After changing the measurement conditions, re-concentration detection is performed.

  In S16, the detection pattern conditions obtained from the above results are set as HS detection pattern printing conditions and stored in the memory. In S <b> 17, the above process is repeated in the same manner for the types of colors to be evaluated constituting the head, and the conditions for each color are set. In the above embodiment, there are four colors.

  FIG. 8 is a flowchart showing the detection pattern printing operation (S2).

  In S21, a detection pattern is printed based on the acquired detection pattern condition. At this time, the density pattern is adjacent to each recording element, and a positioning pattern is printed. In S22, printing is performed a plurality of times in order to take into account fluctuations in the discharge conditions. In S23, printing is performed for the number of colors that are configured.

  FIG. 9 is a flowchart showing the reading operation (S3).

  In S31, the measurement start position is detected, and the pattern number and pattern position at this time are recorded in the memory. In S32, the position detection pattern and the measurement pattern arranged on the designated main scanning line are measured under the conditions acquired by the calibration in Step S1 and stored in the memory.

  In S33, after the measurement on one scanning line is completed, the sheet is conveyed in the sub-scanning direction. In S34, the designated number of patterns are detected in the same manner as described above. In S35, the above sequence is repeated in the same manner as described above for four colors.

  FIG. 10 is a flowchart showing the operation (S4) of the HS data calculation routine.

  In S41 and S42, the pattern position and the nozzle position are first detected from the data stored in the memory in S31 to S34, the density data of the same pattern is calculated according to the conditions, and the density data is associated with each ejection term.

  In S43, the variation amount of the ejection amount of each printing element is calculated using the density data of the density unevenness detection pattern. In S44, HS data is calculated. In S45, the above processing is performed for a plurality of detection patterns. Process in the same manner as above. In S46, the four color classification is repeated and the calculation routine is terminated.

  Here, HS data for a plurality of detection patterns is calculated for each color, but these may be averaged as HS data used for density unevenness correction, and the mode value may be used. May be.

  According to the head shading process, since the correspondence between the density data of the density unevenness detection pattern and each ejection port is accurately performed, appropriate density unevenness correction data (HS data) can be calculated. As a result, an image having no density unevenness can be recorded.

  The above embodiments are not limited to ink jet recording, but can be applied to thermal transfer recording, thermal recording, and the like.

  In the above-described embodiment, in a method for detecting density unevenness of a print pattern formed by a recording head in which a plurality of recording elements are arranged, a discharge amount detection method in which a two-dimensional matrix sensor is configured in a reading mechanism and driven in the sensor main scanning direction In FIG. 5, a print pattern position detection pattern is formed adjacent to the detection print pattern. The measurement position of each pattern can be detected by this measurement position detection pattern. Furthermore, the measurement position detection pattern constitutes a pattern that is repeated with a period equal to or less than the effective pixel width of the two-dimensional matrix sensor. Further, a non-repetitive pattern is formed in the range of the effective pixel range. The sensor is configured as a carriage that drives the head, and reads the measurement position detection pattern and the density detection pattern at arbitrary intervals while scanning the sensor in the main scanning direction. At this time, the read data is data read by pixels at different positions at which the two-dimensional matrix sensor is moving.

  However, from the measurement position pattern information, different read pixels can be specified by the respective two-dimensional sensors for the pattern data at the same position.

  Accordingly, it is possible to measure a plurality of different pixel data in a short measurement time, and to calculate the measurement pattern data at the same position from this result, and obtain a result with high accuracy equivalent to the conventional measurement method.

  Further, since the measurement can be performed at high speed, the scanning speed can be improved, the detection pattern width can be reduced, and the detection time can be shortened.

  Further, in the recording density unevenness correction method according to the embodiment, in the step of printing the recording pattern of each recording element using all the recording elements of the recording head in which a plurality of recording elements are arranged, the detected density data is: There is a step of associating the print position information of the carriage driving mechanism with the print position of the recording element, and associating the nozzle position of the recording element with the detected density data stored in the memory.

  Furthermore, the recording density unevenness correction data creation method according to the above embodiment includes a step of storing the position information of the recording element of the recording head on the memory, and a density unevenness detection created using all the recording elements of the recording head. From the step of reading the pattern and the step of storing the density unevenness detection pattern density data in the memory, the positional information of the printing element on the memory and the density data are correlated to create correction data for each printing element. The process of carrying out.

  Further, density unevenness of a recording pattern formed by a recording head in which a plurality of recording elements are arranged is detected, and density data of each recording element is corrected. In the printing density unevenness correction method according to the embodiment, the printing process of printing the pattern detectable by the resolution ability of the pattern detection reading sensor in the process of printing the density unevenness detection pattern using the plurality of recording elements. And a step of printing a position detection pattern of a recording element in association with the density unevenness detection pattern using at least one specific recording element selected from the plurality of recording elements, and the printed above A step of detecting the density of the density unevenness detection pattern; and a process of corresponding the density data of the density unevenness detection pattern and the recording elements.

  Here, the recording apparatus may further include means for creating density correction data based on the density data corresponding to each recording element by the corresponding means.

  Furthermore, the recording apparatus may further include means for correcting an image recorded by the recording head in accordance with the correction data created by the creating means.

  The recording head may be a head that performs recording with different colors. The recording head may be a head that ejects ink, or may be a form that ejects ink with thermal energy or mechanical energy.

Further, the recording head may be a head that performs recording by serial scanning. Further, the density unevenness detection pattern may be formed by being scanned a plurality of times by the recording head. The recording head may have a width equal to the width of the recording medium.

1 is a diagram illustrating a configuration example of an inkjet head cartridge 21 in an inkjet recording apparatus P1 that is Embodiment 1 of the present invention. FIG. It is an external appearance perspective view which shows an example of the inkjet recording device P1 provided with the mechanism for the said head shading process. It is explanatory drawing of the density | concentration detection method using the two-dimensional matrix sensor for density | concentration unevenness detection. It is a figure which expands and shows the measurement state of a two-dimensional matrix sensor. It is a figure which expands and shows the measurement state of a two-dimensional matrix sensor. It is a flowchart which shows the sequence outline | summary of head shading. It is a flowchart which shows the calibration operation | movement of a detection sensor. It is a flowchart which shows the operation | movement (S2) of detection pattern printing. It is a flowchart which shows reading operation | movement (S3). It is a flowchart which shows operation | movement (S4) of HS data calculation routine. 2 is a block diagram showing an image processing unit 200. FIG. It is a figure which shows the example which has arrange | positioned the detection pattern which changed conditions for every head of multiple colors on the recording medium. It is explanatory drawing of a prior art example. It is the schematic which shows the structure of a detection pattern of the prior art example, a reading unit, its scanning part, and operation | movement. 2 is a diagram showing an outline of a reading mechanism 210. FIG.

Explanation of symbols

P1 ... inkjet recording apparatus,
10 ... ink tank,
20: Recording head,
21 ... cartridge,
101 ... measurement pattern,
1116 ... Pattern A,
200: Image processing unit,
210: Reading mechanism.

Claims (12)

In a recording apparatus having a recording density unevenness correcting function for detecting density unevenness of a recording pattern formed by a recording head in which a plurality of recording elements are arranged and correcting density data of each recording element.
Means for printing a density unevenness detection pattern using the plurality of recording elements;
A density reading device that reads density data from the density unevenness detection pattern;
A memory for storing the read density data, measurement position data, and position information data of each recording element;
Arithmetic processing means for arithmetically processing density data at the same position captured by different pixels of the sensor configured in the reading means;
Means for taking correspondence between the density data and position information of each element;
A recording apparatus comprising: In claim 1,
The density reading apparatus is a sensor having a two-dimensional matrix configuration. In claim 1,
A measurement position detection pattern is configured adjacent to the density detection pattern,
The recording apparatus is characterized in that the same pattern is repeated with a width equal to or smaller than the effective pixel width of the reading sensor, and each pattern is arranged under a condition having no periodicity in the repeated pattern. In claim 1,
A recording apparatus comprising: a creation unit that creates density correction data based on density data corresponding to each recording element by the correspondence unit. In claim 4,
A recording apparatus comprising: means for correcting an image recorded by the recording head according to density correction data created by the creating means. In claim 1,
The recording apparatus, wherein the recording head is a head that ejects ink by thermal energy or a head that ejects by mechanical energy. In a recording method having a recording density unevenness correction function for detecting density unevenness of a recording pattern formed by a recording head in which a plurality of recording elements are arranged and correcting density data of each recording element,
Printing a density unevenness detection pattern using the plurality of recording elements;
A storage step of storing density data, measurement position data, and position information data of each recording element obtained from the density unevenness detection pattern in a memory;
And processing the plurality of data captured by different pixels of the sensor configured as the reading means, and taking the correspondence between the density data and the position information of each element, the density data at the same position is obtained. A recording method characterized by being obtained. In claim 7,
The density reading is performed by a sensor having a two-dimensional matrix configuration. In claim 7,
The measurement position detection pattern is configured adjacent to the density detection pattern, and the same pattern is repeated with a width equal to or smaller than the effective pixel width of the reading sensor. In addition, each pattern has a non-periodic condition. A recording method characterized by being arranged in the above. In claim 7,
A recording method comprising: a creation step of creating density correction data based on density data corresponding to each recording element by the correspondence. In claim 10,
A recording method comprising: correcting an image recorded by the recording head according to density correction data created by the creating step. In claim 7,
A recording method, wherein the recording head ejects ink with thermal energy or mechanical energy.

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