JP6582873B2 - Image forming apparatus, program, and method - Google Patents

Description

  The present invention relates to an image forming apparatus, a program, and a method.

  A handheld printer (hereinafter referred to as HHP (Hand Held Printer)) that forms an image on paper by ejecting ink from the device when the user grips the device, scans the device, and reaches the image forming position is put into practical use. It is being done. Since the HHP does not have a paper transport unit, it is a size that can be carried by the user.

  FIG. 1 is an example of a diagram schematically illustrating image formation by the HHP 1. The HHP 1 receives image data from an image data output device 9 such as a smartphone or a PC (Personal Computer). The user grips HHP1 and scans HHP1 freehand. The HHP 1 includes a sensor for detecting a position on a bottom surface in contact with the paper surface and an IJ (Ink Jet) recording head. The HHP 1 detects the position on the paper by a sensor, and ejects ink from the IJ recording head when the IJ recording head reaches the ejection position. Since the portion where ink has already been ejected is masked, the HHP 1 does not eject ink even if it reaches the once ejected portion again.

  The HHP calculates the current position information based on the output value from the sensor, but an error may occur in the calculated position information. Therefore, there is a technique for measuring an error in position information obtained by the HHP and correcting the position information in accordance with the error.

  For example, a method is known in which a scale factor is generated based on a difference between a movement path detected from a navigation measurement value and an actual movement path, and an error in position data detected by the apparatus is corrected using the scale factor. (For example, refer to Patent Document 1).

  However, the conventional technique cannot correct the error of the position information generated due to the displacement of the position of the sensor with respect to the HHP. For example, the position of the sensor may deviate from the position where it should originally be placed between HHPs due to individual differences in HHP that occur during manufacturing. In addition, due to aging of HHP, the position of the sensor may deviate from the position where it should be originally placed as compared to when HHP is used. As a result, there is a problem that an error occurs in the position information obtained from the sensor and the printing position is shifted.

  Therefore, in view of the above problems, the present embodiment aims to determine an appropriate print position based on position information detected by a sensor.

  In one proposal, an image forming apparatus for forming an image on a medium, the detection means for reading the medium and acquiring surface information, and the movement amount calculation for calculating the movement amount of the image forming apparatus based on the acquired surface information An image forming apparatus is provided that includes a correction unit that corrects the amount of movement based on basic surface information acquired by the detection unit reading a predetermined pattern.

  An appropriate printing position can be determined based on the position information detected by the sensor.

It is an example of the figure which shows the image formation by HHP typically. It is a figure for demonstrating the detection of the height and inclination | tilt angle of a sensor. It is a figure which shows the hardware constitutions of HHP. It is an example of the figure explaining the structure of a control part. It is a block diagram of a sensor. It is a figure for demonstrating the detection of the movement component of the linear direction by a sensor. It is a figure for demonstrating the detection of the rotation component by a sensor. It is a figure which shows the apparatus used when performing calibration. It is explanatory drawing in the case of measuring the shift | offset | difference of a height direction. It is a figure which shows the original image and acquired image in the 1st example which measures the shift | offset | difference of the height direction of a sensor. It is a figure which shows an example of the relationship table of the size and resolution of a captured image. It is a figure which shows the relationship between the resolution and the height of the sensor. It is a figure which shows the original image and acquired image in the 2nd example which measures the shift | offset | difference of the height direction of a sensor. It is a figure which shows the screen and the acquired image in the 3rd example which measures the shift | offset | difference of the height direction of a sensor. It is a figure which shows the original image and acquired image in the 4th example which measures the shift | offset | difference of the height direction of a sensor. It is a figure which shows the example which measures the inclination of the XZ direction of a sensor. It is a figure which shows the positional relationship of each site | part of the bottom face of HHP. It is a figure which shows the influence by the inclination of a XY direction of a sensor. It is a 1st figure which shows the example of a pattern of the figure used for a calibration. It is a 2nd figure which shows the example of the pattern of the figure used for calibration. It is a figure which shows the whole flow of a calibration process. It is a figure for demonstrating the position calculation method of a sensor. It is a 1st figure for demonstrating calculation of the head nozzle position. It is a 2nd figure for demonstrating calculation of the head nozzle position. It is a 1st figure for demonstrating calculation of the position of the nozzle in the middle of a head and a tail nozzle. It is a 2nd figure for demonstrating calculation of the position of the nozzle in the middle of a head and a tail nozzle.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has substantially the same function structure, the duplicate description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[Embodiment 1]
<Outline of calibration process>
FIG. 2 is a diagram for explaining detection of sensor height and tilt angle. Calibration is performed in order to measure the deviation of the sensor height and the tilt angle with respect to the paper when the HHP 20 is placed on the paper. The calibration is executed, for example, in a test process at the time of manufacturing the HHP 20 and before the user uses the HHP 20. The display device 10 may be a device such as a smartphone or a tablet terminal.

  When executing the calibration, the user places the HHP 20 on the screen 11 of the display device 10 and presses the calibration button 5 as shown in FIG. When the calibration button 5 is pressed, the LED 6 is turned on. The LED 6 is lit until the calibration process is completed. Subsequently, the HHP 20 starts a calibration process.

  The left side of FIG. 2B shows the screen 11 of the display device 10 when the HHP 20 is placed. For example, the display device 10 displays a bar-shaped figure 12 on the screen 11. When the surface of the screen 11 is the XY plane, at the start of calibration, for example, the bar-shaped figure 12 is displayed at a position on the left side of the screen 11 parallel to the Y axis. Subsequently, the display device 10 moves the bar-shaped figure 12 to the right side parallel to the X axis.

  The right side of FIG. 2B shows the bottom surface of the HHP 20. On the bottom surface of the HHP 20, sensors 30 a and 30 b are arranged above and below the IJ recording head 24. When calibration is started, the sensor 30a and the sensor 30b each detect the position of the bar-shaped figure 12 and measure the movement amount ΔX of the bar-shaped figure 12. Note that the display device 10 may further move the bar-shaped figure 12 parallel to the X axis in parallel to the Y axis direction, and cause the sensor 30a and the sensor 30b to measure the movement amount ΔY.

  FIG. 2C shows the screen 11 when the position where the HHP 20 is placed is displayed. The guide 13 displayed with a dotted line has the same shape as the bottom surface of the HHP 20. The user can place the HHP 20 at an accurate position by placing the bottom surface of the HHP 20 in accordance with the guide 13.

  The left side of FIG. 2D shows the amount of movement measured when the sensor 30b is correctly arranged. A line passing through the sensors 30a and 30b is assumed to be perpendicular to the X axis and parallel to the Y axis. When the sensor 30b is arranged at a correct position without tilting, the sensor 30b correctly measures the movement amount ΔX of the HHP 20 in the X-axis direction and the movement amount ΔY in the Y-axis direction.

  The right side of FIG. 2D shows the amount of movement measured when the sensor 30b is tilted in the XY direction. It is assumed that the sensor 30b is disposed at an angle θ in the XY direction and the counterclockwise direction. Compared with the case where the sensor 30b is correctly arranged, the sensor 30b has a larger measured value of ΔX, a smaller measured value of ΔY, and an error occurs in the measured movement amount. Further, errors in ΔX and ΔY also occur due to the height deviation of the sensor 30b and the inclination in the XZ direction and the YZ direction.

  For example, in the case of the right side of FIG. 2D, the HHP 20 uses the correction coefficient calculated in advance by the calibration process so that the movement amount ΔX is the same as when the sensor 30b is correctly arranged. And ΔY are corrected. Thereby, even if the displacement of the sensor 30 occurs due to individual differences of the HHP 20 and aging, etc., the movement amount of the HHP 20 can be correctly measured and the accurate position of the apparatus can be detected.

<Hardware configuration>
FIG. 3 is a diagram illustrating a hardware configuration of the HHP 20. The HHP 20 is an example of an image forming apparatus that forms an image on a print medium. The overall operation of the HHP 20 is controlled by the control unit 25. The control unit 25 includes a communication I / F (Interface) 27, an IJ recording head drive circuit 23, an OPU (Operation Unit) 26, a ROM (Read Only Memory) 28, A DRAM (Dynamic Random Memory) 29 and a sensor 30 are electrically connected. Further, since the HHP 20 is driven by electric power, it has a power source 22 and a power source circuit 21. The electric power generated by the power supply circuit 21 is supplied to the communication I / F 27, the IJ recording head drive circuit 23, the OPU 26, the ROM 28, the DRAM 29, the IJ recording head 24, the control unit 25, and the sensor 30 by wiring shown by dotted lines. Yes.

  The power source 22 is mainly a battery. A solar cell, a commercial power source (AC power source), a fuel cell, or the like may be used. The power supply circuit 21 distributes the power supplied from the power supply 22 to each part of the HHP 20. Further, the voltage of the power supply 22 is stepped down or boosted to a voltage suitable for each part. In addition, when the power source 22 can be charged by a battery, the power source circuit 21 detects the connection of the AC power source and connects it to the battery charging circuit so that the power source 22 can be charged.

  The communication I / F 27 receives image data from the image data output device 9 such as a smartphone or a PC. The communication I / F 27 is a communication device corresponding to a communication standard such as a wireless LAN, Bluetooth (registered trademark), NFC (Near Field Communication), infrared, 3G (mobile phone), or LTE (Long Term Evolution). In addition to such wireless communication, a communication device that supports wired communication using a wired LAN, a USB cable, or the like may be used.

  The ROM 28 stores firmware that performs hardware control of the HHP 20, drive waveform data of the IJ recording head 24 (data that defines voltage changes for ejecting droplets), initial setting data of the HHP 20, and the like.

  The DRAM 29 is used for storing image data received by the communication I / F 27 and storing firmware developed from the ROM 28. Therefore, it is used as a work memory when the CPU 31 executes the firmware.

  The sensor 30 is a sensor that detects the position of the HHP 20. The sensor 30 includes, for example, a light source such as a light emitting diode (LED) or a laser and an image sensor that images the print medium 2 or a sensor that images interference fringes of incident / reflected light. When the HHP 20 is scanned over the print medium 2, minute edges of the print medium 2 are detected one after another (imaged), and the amount of movement is obtained by analyzing the distance between the edges. The sensors 30 are mounted on at least two places of the HHP 20. When distinguishing both, it is called sensors 30a and 30b. In addition, as the sensor 30, a multi-axis acceleration sensor, a gyro sensor, or the like may be used, or the position of the HHP 20 may be detected only by the acceleration sensor or the gyro sensor.

  The OPU 26 includes an LED 6 that displays the state of the HHP 20, a switch (for example, a calibration button 5) for the user to instruct the HHP 20 to form an image, and the like. However, the present invention is not limited to this, and may have a liquid crystal display and may further have a touch panel. Further, it may have a voice input function.

  The IJ recording head driving circuit 23 generates a driving waveform for driving the IJ recording head 24 using the above-described driving waveform data. A drive waveform corresponding to the ink droplet size can be generated.

  The IJ recording head 24 is a head for ejecting ink. In the figure, four colors of CMYK ink can be ejected, but it may be a single color or ejecting five or more colors. A plurality of nozzles for ink ejection (described later) arranged in one row (may be two or more rows) for each color are arranged. Further, the ink ejection method may be a piezo method or a thermal method, or any other method.

  Based on the amount of movement detected by the sensor 30, the control unit 25 determines the position of each nozzle of the IJ recording head 24, determines the image to be formed according to the position, determines whether or not the discharge nozzle is available (the position of the nozzle from the target discharge position). Etc.). Details of the control unit 25 will be described below.

  FIG. 4 is an example of a diagram illustrating the configuration of the control unit 25. The control unit 25 includes a SoC (System On a Chip) 50 and an ASIC (Application Specific Integrated Circuit) / FPGA (Field Programmable Gate Array) 40. The SoC 50 and the ASIC / FPGA 40 communicate via a bus 47 and a bus 48. It means that the ASIC / FPGA 40 may be designed by any mounting technology, and may be configured by other mounting technology other than the ASIC / FPGA 40. Further, the SoC 50 and the ASIC / FPGA 40 may be configured as a single chip or substrate without using separate chips. Alternatively, it may be implemented with three or more chips or substrates.

  The SoC 50 has functions such as a CPU 31, a position calculation circuit 32, a memory CTL (controller) 35, and a ROMCTL (controller) 36 connected via a bus 48. In addition, the component which SoC50 has is not restricted to these.

  The ASIC / FPGA 40 includes an image RAM (Image Random Access Memory) 37, a DMAC (Direct Memory Access Controller) 38, a rotator 39, an interrupt controller 41, a sensor I / F 42, and print / sensor timing connected via a bus 47. A generation unit 43 and an IJ recording head control unit 44 are provided. In addition, the component which ASIC / FPGA40 has is not restricted to these.

  The CPU 31 executes firmware (program) or the like developed from the ROM 28 to the DRAM 29, and controls operations of the position calculation circuit 32, the memory CTL (Controller) 35, and the ROMCTL 36 in the SoC 50. Further, it controls the operations of the ImageRAM 37, DMAC 38, rotator 39, interrupt controller 41, sensor I / F 42, print / sensor timing generation unit 43, and IJ recording head control unit 44 in the ASIC / FPGA 40.

  The position calculation circuit 32 calculates the position (coordinate information) of the HHP 20 based on the movement amount for each sampling period detected by the sensor 30. Strictly speaking, the position of the HHP 20 is the position of the nozzle, but if the position of the sensor 30 is known, the position of the nozzle can be calculated. In the present embodiment, when referring to either the sensor 30a or the sensor 30b, the sensor 30 may be indicated. The position calculation circuit 32 calculates a target discharge position.

  The position of the sensor 30 is calculated based on, for example, a predetermined origin (for example, printing paper or the upper left corner of the image data 7). Further, the position calculation circuit 32 estimates the moving speed and the moving direction based on the difference between the past position and the newest position, and predicts the position at the next calculation timing, for example. In this way, it is possible to discharge ink while suppressing a delay with respect to scanning by the user.

  The memory CTL 35 is an interface with the DRAM 29, requests data from the DRAM 29, sends the acquired firmware to the CPU 31, and sends the acquired image data 7 to the ASIC / FPGA 40.

  The ROMCTL 36 is an interface with the ROM 28, requests data from the ROM 28, and sends the acquired data to the CPU 31 and the ASIC / FPGA 40.

  The DMAC 38 acquires the image data 7 around each nozzle of the IJ recording head 24 via the memory CTL 35 based on the position information calculated by the position calculation circuit 32. That is, the image data 7 around the position where the HHP 20 exists with respect to the print medium 2 is acquired.

  The rotator 39 rotates the image data acquired by the DMAC 38 in accordance with the head that ejects ink and the nozzle position in the head. The DMAC 38 outputs the rotated image data to the IJ recording head control unit 44. For example, the rotator 39 can acquire the rotation angle θ calculated when the position calculation circuit 32 calculates the position, and can rotate the image using the rotation angle θ.

  The ImageRAM 37 temporarily stores the image data 7 acquired by the DMAC 38. That is, a certain amount of image data 7 is buffered and read according to the position of the HHP 20.

  The IJ recording head control unit 44 performs dither processing on the image data 7 (bitmap data) to convert the image data 7 into a set of points representing an image with size and density. As a result, the image data 7 becomes data of the ejection position and the dot size. The IJ recording head control unit 44 outputs a control signal corresponding to the dot size to the IJ recording head drive circuit 23. The IJ recording head drive circuit 23 generates a drive waveform using the drive waveform data corresponding to the control signal as described above.

  The sensor I / F 42 communicates with the sensor 30, receives the movement amounts ΔX and ΔY as information from the sensor 30, and stores the values in an internal register. ΔX and ΔY indicate the amount of movement in the X-axis direction and the Y-axis direction of the image displayed on the screen 11 with the screen 11 of the display device 10 shown in FIG.

  The print / sensor timing generation unit 43 notifies the sensor I / F 42 of the timing for reading the information of the sensor 30, and notifies the IJ recording head control unit 44 of the drive timing. The IJ recording head control unit 44 determines whether or not the ejection nozzle is available, and determines that ink is ejected if there is a target ejection position where ink should be ejected, and that ejection is not performed if there is no target ejection position.

  The interrupt controller 41 detects that the sensor I / F 42 has completed communication with the sensor 30, and outputs an interrupt signal for notifying the SoC 50 of the completion. The CPU 31 acquires ΔX and ΔY stored in the internal register by the sensor I / F 42 by this interruption. In addition, it has a status notification function for errors and the like.

  FIG. 5 is a block diagram of the sensor 30. The sensor 30 includes a Host I / F 55, an image processor 51, an LED / LASERDrive 52, a lens 53 a, a lens 53 b, and an image array 54.

  The LED / LASERDrive 52 controls the irradiation of the laser light from the LED. The LED / LASERDrive 52 converts the laser light received from the LED / LASERDrive 52 by the lens 53a into parallel light, and irradiates a predetermined range of the print medium 2 with the parallel laser light. The image array 54 receives the reflected light from the print medium 2 via the lens 53b and transmits it to the image processor 51 as image data. The image processor 51 calculates the movement amounts ΔX and ΔY based on the received image data. The image processor 51 transmits data relating to the movement amounts ΔX and ΔY to an external terminal via the Host I / F 55.

  FIG. 6 is a diagram for explaining the detection of the moving component in the linear direction by the sensor 30. FIG. 6A shows a case where the print medium 2 is irradiated with an LED laser from the sensor 30. The LED / LASERDrive 52 converts the laser light from the LED / LASERDrive 52 into parallel light by the lens 53 a and irradiates the laser light to a predetermined range of the print medium 2. The image array 54 receives the reflected light from the print medium 2 via the lens 53b and transmits it to the image processor 51 as image data.

  FIG. 6B shows image data generated by the image array 54. Samp1, Samp2, and Samp3 are image data received by the image array 54 and matrixed by the image processor 51 with a predetermined resolution. For example, in the case of a printer, the matrix is formed with a resolution of about 1200 dpi. Samp1, Samp2, and Samp3 are image data acquired at each time when the HHP 20 is moved in parallel to the X-axis direction at a predetermined speed, and start from Samp1 in the order of Samp2, Samp3. It is the acquired image data.

  Compared to Samp1, Samp2 has the image moved to the left by one square. Compared to Samp1, Samp3 has the image moved to the left by 2 squares. Therefore, the movement amount of the HHP 20 from Samp1 to Samp2 is (ΔX, ΔY) = (1,0), and the movement amount of the HHP20 from Samp1 to Samp3 is (ΔX, ΔY) = (2,0). Become. When the HHP 20 is moved in the Y axis direction, the image moves in the vertical direction, and the value of ΔY changes.

  Further, if image data is acquired with a higher resolution by the image array 54, a more detailed movement amount can be measured.

  FIG. 7 is a diagram for explaining the detection of the rotation component by the sensor 30. FIG. 7A shows the bottom surface of the HHP 20. FIG. 7B shows the IJ recording head 24 and the nozzles 24a to 24f.

  The HHP 20 of this embodiment has two or more sensors 30. Since the HHP 20 includes two or more sensors 30, the rotation angle θ can be detected even if the sensors 30 rotate on the print medium. For example, in FIG. 7A, two sensors 30a and 30b are arranged apart from each other in the arrangement direction of the nozzles 24a to 24f. The length between the two sensors 30a and 30b is a distance L. The rotation angle θ can be calculated using the difference in the amount of movement of the sensors 30a and 30b in the X-axis direction or the Y-axis direction and the distance L.

  Also, the longer the distance L, the smaller the minimum rotation angle θ that can be detected, and the smaller the position error of the HHP 20, so the longer the distance L, the better.

  The distances from the sensor 30a to the IJ recording head 24 are distances a and b, respectively. The distance a is equal to the distance b. As shown in FIG. 7B, the distance from the tip of the IJ recording head 24 to the first nozzle is a distance d, and the distance between adjacent nozzles is a distance e. The values of the distances a to e are stored in advance in the ROM 28 or the like.

  The position calculation circuit 32 can calculate the position of each nozzle from the positional relationship with the sensor 30 by calculating the position of the sensor 30.

  In this embodiment, the horizontal direction to the print medium 2 is set as the X axis, and the vertical direction is set as the Y axis. On the other hand, the sensor 30 outputs a position on the following coordinate axes (X ′ axis, Y ′ axis). That is, the direction in which the nozzles 24a to 24f are arranged (the direction parallel to the line passing through the two sensors 30a and 30b) is the Y ′ axis, and the direction orthogonal to the Y ′ axis is the X ′ axis.

<Three types of measurements performed by calibration>
FIG. 8 is a diagram illustrating an apparatus used when executing calibration. As shown in FIG. 8A, the HHP 20 may be placed on the display device 10 and calibration may be executed. Note that the operation method for performing calibration by placing the HHP 20 on the display device 10 has been described with reference to FIG.

  Further, as shown in FIG. 8B, the calibration may be executed by bringing the HHP 20 into close contact with the paper 3 on which the image is printed. In the case of FIG. 8B, calibration is executed using an apparatus that moves the sheet 3 in the X-axis direction and the Y-axis direction with the HHP 20 fixed at the same position.

  The HHP 20 detects the displacement in the height direction and the displacement in the tilt direction of the sensors 30a and 30b by executing calibration.

  For example, when the screen 11 of the display device 10 is the XY plane and the Z axis is in the vertical direction of the XY plane, the deviation in the height direction indicates a deviation in the Z axis direction. Further, the displacement in the tilt direction is classified into two types, one is the tilt of the sensor 30 in the XZ direction and the YZ direction, and the other is the sensor 30 in the clockwise direction or the counterclockwise direction with respect to the XY plane. Is the inclination in the X and Y directions.

  The HHP 20 performs calibration by detecting an image displayed on the screen 11 of the display device 10, and includes deviations in the height direction (Z-axis direction), inclinations in the XZ direction and the YZ direction, and inclinations in the XY direction. Three are measured individually.

  Hereinafter, three measurements of the deviation in the height direction (Z-axis direction), the inclination in the XZ direction and the YZ direction, and the inclination in the XY direction at the time of performing calibration will be described.

<Measurement of displacement in the height direction (Z-axis direction)>
For example, the HHP 20 measures the deviation in the height direction by the following four methods.

  FIG. 9 is an explanatory diagram in the case of measuring the deviation in the height direction. A first example of measuring the deviation in the height direction will be described with reference to FIGS. 9 to 13. (A) shows the case where the sensor 30 is arranged at a normal height, and (b) shows the case where the sensor 30 is arranged higher than the left side by a distance h in the Z-axis direction.

  As shown in FIG. 9A, the LED / LASERDrive 52 uses a lens 53a to convert the laser light from the LED / LASERDrive 52 into parallel light, and irradiates the laser beam with the parallel light onto a predetermined range of the print medium 2. The image array 54 acquires the reflected light from the print medium 2 via the lens 53b and transmits it to the image processor 51 as image data. The image processor 51 generates image data in a matrix form with a predetermined resolution.

  Comparing the cases of (a) and (b) of FIG. 9, the resolution of the image acquired by the image array 54 from the reflected light is higher than that of (a) due to the fact that it is arranged higher by the distance h in the Z axis direction. (B) becomes lower.

  FIG. 10 is a diagram illustrating the original image and the acquired image in the first example in which the displacement of the sensor 30 in the height direction is measured. FIG. 10A shows an original image represented on the print medium 2. 10B and 10C show images acquired by the image array 54 corresponding to FIGS. 9A and 9B, respectively. One cell in FIGS. 10B and 10C corresponds to 1000 dpi × 1000 dpi.

  FIG. 10B shows an image acquired by the image array 54 in the case of FIG. 9A, and the size of the image is 2 cells in the X-axis direction and 2 cells in the Y-axis direction. Yes. Therefore, one side of the square image in FIG. 10B is 50.8 μm (= 25.4 / 1000 × 2).

  FIG. 10C shows an image acquired by the image array 54 in the case of FIG. 9B, and the size of the image is one cell in the X-axis direction and one cell in the Y-axis direction. Yes. Therefore, one side of the square image in FIG. 10C is 25.4 μm (= 25.4 / 1000 × 1), and the resolution is lower than that in the case of FIG.

  As described above, the size of the image data changes depending on the height of the sensor 30. The lower the height of the sensor 30, the higher the resolution of the image, and the higher the height of the sensor 30, the lower the resolution of the image. That is, the height of the sensor 30 and the resolution of the image are related, and the height of the sensor 30 can be obtained from the resolution of the image. It is also possible to obtain the image resolution from the height of the sensor 30.

  Therefore, the height detection unit 45 can detect the height of the sensor 30 based on the resolution of the image acquired from the sensor 30.

  FIG. 11 is a diagram illustrating an example of a relationship table between the size and resolution of a captured image. The relationship table of FIG. 11 shows the relationship between the number of cells per side of the captured image, the height (mm) of the sensor 30, and the resolution (dpi) of the sensor. The number of cells corresponding to one side of the graphic 12 displayed on the screen 11 is counted, and the resolution (dpi) corresponding to the current height (mm) of the sensor 30 is obtained by comparing with the relation table of FIG. Can do.

  For example, the relationship table of FIG. 11 shows the relationship between the number of cells and the sensor resolution when the length of one side of the figure 12 is 254 μm, the standard height of the sensor 30 is 2.5 mm, and the set resolution is 1000 dpi. ing.

  For example, the relationship table according to FIG. 11 may be held in the ROM 28, and the position calculation circuit 32 may be used when correcting the movement amounts ΔX and ΔY of the sensor 30. Further, a coefficient used in a mathematical expression indicating the relationship between the number of cells measured by the sensor 30 and the resolution is held in the ROM 28 as a correction coefficient, and the position calculation circuit 32 corrects the movement amounts ΔX and ΔY of the sensor 30. It may be used in some cases. For example, the correction coefficient may be a value obtained by dividing the actual movement amount of the HHP 20 (the movement amount of the graphic 12 at the time of calibration) by the movement amount detected by the sensor 30.

  FIG. 12 is a diagram illustrating the relationship between the resolution and the height of the sensor 30. The vertical axis of the graph shown in FIG. 12 indicates resolution (dpi), and the horizontal axis indicates height (mm). The graph is almost a straight line in the height range of 2.0 mm to 3.0 mm, and it can be seen that a proportional relationship is established between the height and the resolution. That is, the higher the height of the sensor 30, the lower the resolution, and the lower the height of the sensor 30, the higher the resolution.

  In addition, there is a height range in which the movement amount of the HHP 20 can be stably measured by the sensor 30. For example, in the example of FIG. 12, the height at which the movement amount of the HHP 20 can be stably measured by the sensor 30 is 2.0 mm to 3.0 mm.

  The height detection unit 45 obtains the height of the sensor 30 based on the measured resolution of the sensor 30. For example, the height detection unit 45 determines that the height of the sensor 30 is 2.0 mm when the measured resolution is 800 dpi. Moreover, the height detection part 45 determines with the height of the sensor 30 being 2.5 mm, when the measured resolution is 1000 dpi. Moreover, the height detection part 45 determines with the height of the sensor 30 being 3.0 mm, when the measured resolution is 1200 dpi. There is a correlation between the resolution (height of the sensor 30) and the amount of movement of the HHP 20. The lower the resolution, the higher the height of the sensor 30, and the amount of movement of the HHP 20 is detected to be larger than the actual amount of movement of the HHP 20. The Therefore, the movement amount of the HHP 20 can be corrected by detecting the height of the sensor 30 based on the resolution.

  FIG. 13 is a diagram illustrating the original image and the acquired image in the second example in which the displacement in the height direction of the sensor 30 is measured. A method for measuring the deviation in the second height direction will be described. (A) shows an original image on which a plurality of figures having different particle sizes printed on the print medium 2 are displayed. (B), (C), and (D) are images acquired by the image processor 51. (B) is an image acquired when the height of the sensor 30 is the lowest, and is an image acquired when the height of the sensor 30 is high in the order of (C) and (D). As shown in (A), four figures with different granularities are displayed in the original image. When the height of the sensor 30 is the lowest (B), all four figures displayed in the original image are displayed. Next, when the height of the sensor 30 is low (C), among the four figures displayed in the original image, three figures are displayed, and the leftmost figure with the smallest granularity cannot be read. When the height of the sensor 30 is the highest (D), two figures are displayed out of the four figures displayed in the original image, and the first figure and the second figure from the left cannot be read. . Further, in the case of (D), the boundary line of the rightmost graphic is unclear, and the original image is a square shape, whereas the original image is a square shape.

  Thus, since the resolution is high when the height of the sensor 30 is relatively low, a figure with a small particle size can be detected, and when the height of the sensor 30 is relatively high, the resolution is low, so the particle size is small. Only large figures can be detected.

  Therefore, the height detection unit 45 can acquire an image of a graphic with a different granularity from the sensor 30 and obtain the resolution based on the detected graphic with the smallest granularity.

  FIG. 14 is a diagram illustrating a screen and the acquired image in the third example of measuring the displacement in the height direction of the sensor 30. A method for measuring the deviation in the third height direction will be described. The diagram on the left side of FIG. 14 shows the screen 11 of the display device 10 when the HHP 20 is placed. For example, the display device 10 displays a bar-shaped figure 12 on the screen 11. When the plane of the screen 11 is the XY plane, at the start of calibration, for example, a bar-shaped figure is displayed at a position on the left side of the screen 11 parallel to the Y axis. Subsequently, the display device 10 gradually moves the bar-shaped figure 12 to the right in parallel with the X axis.

  14A, 14B, and 14C show images acquired by the image array 54 when the height of the sensor 30 is lower than the standard, and FIGS. 14A, 14B, and 14C. These show images acquired by the image array 54 when the height of the sensor 30 is higher than the standard. When the height of the sensor 30 is lower than the standard, the resolution is higher than the standard, and when the height of the sensor 30 is higher than the standard, the resolution is lower than the standard.

  (A) and (a) show images acquired by the image array 54 when the bar-shaped figure 12 is displayed at the initial position of the screen 11. (B) and (b) show images acquired by the image array 54 when the bar-shaped figure 12 is moved a predetermined distance parallel to the X axis on the screen 11. (C) and (c) show images acquired by the image array 54 when the bar-shaped figure 12 is moved to the end position parallel to the X axis on the screen 11.

  When the bar-shaped figure 12 moves from the position (A) to the position (B), the height detection unit 45 detects ΔX = 5 and moves from the position (B) to the position (C). The height detector 45 detects ΔX = 5. Therefore, the height detection unit 45 detects ΔX = 10 when the bar-shaped figure 12 moves from the initial position to the end position.

  On the other hand, when the bar-shaped figure 12 moves from the position (a) to the position (b), the height detector 45 detects ΔX = 2 and moves from the position (b) to the position (c). In this case, the height detection unit 45 detects ΔX = 2. Therefore, the height detection unit 45 detects ΔX = 4 when the bar-shaped figure 12 moves from the initial position to the end position.

  Thus, when the height of the sensor 30 is high (when the resolution is low), the amount of movement of the graphic 12 detected by the sensor 30 is large, and when the height of the sensor 30 is low (when the resolution is high), The moving amount of the figure detected by 30 becomes small. That is, the amount of movement of the figure and the height (resolution) of the sensor 30 are related, and when the figure is moved a certain distance, the height of the sensor 30 is obtained from the amount of movement of the figure detected by the sensor 30. be able to.

  Therefore, the height detection unit 45 obtains the height (resolution) of the sensor based on the movement amount of the graphic detected by the sensor 30 when the graphic is moved by a certain distance.

  FIG. 15 is a diagram illustrating the original image and the acquired image in the fourth example in which the displacement in the height direction of the sensor 30 is measured. A method for measuring a deviation in the fourth height direction will be described. (A) shows the original image printed on the print medium 2. (B), (C) and (D) are images acquired by the image array 54, (B) is an image acquired with the shortest exposure time, and (C) and (D) It is an image acquired by increasing the exposure time in order.

  When the exposure time is the shortest (B), two images are displayed among the four images displayed in the original image, and the first image and the second image from the left cannot be read. Further, the border line of the rightmost image becomes unclear, and the original image is a square shape, whereas the original image is a square shape. Next, when the exposure time is short (C), three images among the four images displayed in the original image are displayed, and the leftmost image cannot be read. When the exposure time is the longest (D), all four images displayed in the original image are displayed.

  When the height of the sensor 30 is high and the resolution is low, the exposure time until a clear image is acquired by the image array 54 becomes long. When the height of the sensor 30 is low and the resolution is high, the image array 54 This shortens the exposure time until a clear image is obtained.

  That is, the height detection unit 45 can obtain the height of the sensor 30 by measuring the exposure time until a clear image is acquired by the image array 54. For example, the height detection unit 45 holds in the ROM 28 a formula that shows the relationship between the exposure time and the height of the sensor 30, or a table that associates the exposure time for each height of the sensor 30, and from the measured exposure time. You may use when calculating | requiring the height of the sensor 30. FIG.

<Measurement of tilt in XZ direction and YZ direction>
FIG. 16 is a diagram illustrating an example of measuring the tilt of the sensor 30 in the XZ direction. Two methods for measuring the tilt in the XZ direction and the YZ direction will be described below by way of example.

  2A shows two cross-sectional views of the HHP 20 parallel to the XZ direction, with the plane of the screen 11 taken as the XY direction, the axis perpendicular to the plane of the screen 11 taken as the Z axis.

  In the figure on the left side of (a), when the bottom surface of the HHP 20 is parallel to the XY plane, the surface of the sensor 30 is parallel to the XY plane. On the other hand, in the figure on the right side of (a), when the bottom surface of the HHP 20 is parallel to the XY plane, the surface of the sensor 30 is inclined with respect to the XY plane.

  (B) shows a case where the LED laser is irradiated from the sensor 30 to the print medium 2. The left diagram in (b) corresponds to the diagram in the left diagram in (a), and shows a case where the print medium 2 is irradiated with an LED laser in a state where the sensor 30 is parallel to the XY plane. Further, the right diagram of (b) corresponds to the diagram of the right diagram of (a), and shows a case where the print medium 2 is irradiated with the LED laser in a state where the sensor 30 is inclined with respect to the XY plane.

  (C) is the figure which expanded a part of printing medium 2 with which the LED laser was irradiated. The striped line represents the irradiation direction of the LED laser. The left figure of (c) corresponds to the left figure of (b), and the LED laser is irradiated to the print medium 2 from a slightly upper left direction, and a shadow is shadowed on the right part of the protrusion on the print medium 2. Has occurred. The right side view of (c) corresponds to the right side view of (b), and the LED laser is irradiated to the print medium 2 from the left side direction than the left side view of (c). In the right side of (c), the LED laser is irradiated from the left side of the left side of (c), and therefore a slightly longer shadow is generated in the right direction of the protrusion (in the positive direction of the X axis).

  (D) shows an image acquired by the image array 54. The two diagrams on the left side of (d) correspond to the diagram on the left side of (c), the left side is an image when the figure 12 is in the initial position, and the right side is the end position when the figure 12 moves. It is an image in some cases. Similarly, the two diagrams on the right side of (d) correspond to the diagram on the right side of (c), the left side is an image when the figure 12 is in the initial position, and the right side is the figure 12 moved. It is an image when in the end position.

  The vertical length of the figure 12 at the initial position in the left side diagram of (d) is 3 cells, the horizontal length is 3 cells, and the aspect ratio is 1: 1. On the other hand, the vertical length of the figure 12 at the initial position in the right side diagram of (d) is 3 cells, the horizontal length is 4 cells, and the aspect ratio is 3: 4. . That is, in the figure on the right side of (d), the shape of the figure 12 is extended by one cell in the X-axis direction because the sensor 30 is inclined in the XZ direction. As described above, the inclination detection unit 46 can detect the inclination of the sensor 30 in the XZ direction based on the shape of the image (for example, the aspect ratio) compared to the image when the sensor 30 is parallel to the XY plane.

  The inclination detector 46 calculates a correction coefficient based on the ratio of the length of the figure in the X-axis direction (horizontal direction) and the length of the figure in the Y-axis direction (vertical direction).

  Further, the tilt of the sensor 30 in the XZ direction can also be detected by the amount of image movement when the print medium 2 is moved by a predetermined distance.

  An example will be described in which the print medium 2 is moved by 6 cells (ΔX = 6) in the X-axis direction. When the sensor 30 is moved by 6 cells in the X-axis direction in a state of being parallel to the XY plane, the inclination detecting unit 46 detects 6 cells from the initial position to the end position of the figure 12 as shown on the left side of FIG. Minute movement (dx = 6) is detected. On the other hand, when the sensor 30 is moved by 6 cells in the X-axis direction in a state where there is an inclination with respect to the XY plane, the inclination detecting unit 46 detects the initial state of the figure 12 as shown in the right side of FIG. A movement of 8 cells from the position to the end position (dx = 8) is detected. As described above, the inclination detection unit 46 can detect the inclination of the sensor 30 in the XZ direction based on the movement amount when the figure is moved at a constant distance in the X-axis direction.

  The inclination detection unit 46 calculates a correction coefficient based on the ratio of the measured movement amount in the X-axis direction and the measured movement amount in the Y-axis direction.

  As described above, the inclination detection unit 46 can detect the inclination of the sensor 30 in the XZ direction by comparing the aspect ratio or the movement amount of the image when the sensor 30 is parallel to the XY plane.

  Further, the inclination detection unit 46 obtains a correction coefficient related to the inclination in the YZ direction by the same method as described above.

<Measurement of tilt in XY direction>
FIG. 17 is a diagram illustrating the positional relationship between the respective parts on the bottom surface of the HHP 20. FIG. 17 is the bottom surface of the HHP 20. An axis parallel to the vertical and horizontal sides of the HHP 20 is defined as an X axis and a Y axis. The X axis is perpendicular to the nozzle arrangement direction of the IJ recording head 24, and the Y axis is parallel to the nozzle arrangement direction of the IJ recording head 24. Moreover, the shape of the sensor 30a and the sensor 30b is, for example, a rectangle, the short side is parallel to the X axis, and the long side is parallel to the Y axis. In the case shown in FIG. 17, it is assumed that the sensor 30a and the sensor 30b are attached without inclination in the XY directions. The shape of the IJ recording head 24 is not limited to a rectangle.

  FIG. 18 is a diagram illustrating the influence of the tilt of the sensor 30 in the XY direction. (A) shows the positional relationship of each site | part of the bottom face of HHP20. As for the positional relationship between the IJ recording head 24 and the sensor 30a, each side is parallel to the X axis and the Y axis, as in FIG. On the other hand, the short side of the sensor 30b is inclined counterclockwise by an angle θ with respect to the X axis.

  (B) shows the amount of movement in the X-axis direction and Y-axis direction measured by each sensor when the HHP 20 is moved ΔX in the X-axis direction and ΔY in the Y-axis direction. (I) is ΔX and ΔY measured by the sensor 30a, which coincides with the actual movement amount of the HHP 20. On the other hand, (ii) is ΔX and ΔY measured by the sensor 30b. ΔX is longer than the actual movement amount of the HHP 20, and ΔY is shorter.

  (C) is a figure for comparing the movement amount which the sensor 30a and the sensor 30b measured. When the axis of ΔX in (ii) is aligned with the axis of ΔX in (i), an error occurs in the measured movement amounts ΔX and ΔY even if the actual movement amounts of the sensor 30a and the sensor 30b are the same. I understand that.

  The inclination detection unit 46 calculates the inclination θ in the XY direction of the other sensor 30 with respect to one sensor 30. For example, assuming that the axis parallel to the short side of the sensor 30a is the X axis and the axis parallel to the long side is the Y axis, the inclination θ in the XY direction of the sensor 30b can be calculated based on the following equation. That is, the inclination θ is an angle difference between the sensors 30a and 30b in the XY directions.

Further, the position calculation circuit 32 can calculate the actual movement amounts ΔX and ΔY by the following formula based on the inclination θ in the XY direction calculated by the formula (1).

ΔX = dx × cos θ + dy × sin θ
ΔY = dx × sin θ−dy × cos θ (1)
As described above, by correcting the error in the movement amount generated between the sensor 30a and the sensor 30b, the error due to the tilt of the sensor 30 in the XY direction can be reduced.

  In addition, the inclination detection unit 46 may record sin θ and cos θ as correction coefficients in the memory 29 and use them when calculating the actual movement amounts ΔX and ΔY.

<Examples of graphic patterns used for calibration>
FIG. 19 is a first diagram illustrating a pattern example of a figure used for calibration. (A) is an image when a plurality of square figures are arranged at equal intervals. By moving the figure (a) in the X-axis direction and the Y-axis direction and obtaining the movement amounts ΔX and ΔY, it is possible to calculate the deviation in the height direction, the inclination in the XZ direction and the YZ direction, and the inclination in the XY direction. . (B) is an image when a plurality of linear figures parallel to the Y-axis direction are arranged. The figure in (b) is used when ΔY is obtained by moving in the Y-axis direction. Further, by using a linear figure parallel to the X-axis direction, the height detection unit 45 and the inclination detection unit 46 can also obtain ΔX by moving the figure in the X-axis direction.

  FIG. 20 is a second diagram illustrating a pattern example of a figure used for calibration. FIGS. 20A and 20B are figures having the same pattern as FIGS. 19A and 19B. However, the mounting position of the HHP 20 is inclined by 45 ° compared to FIG. Compared with 19, the figure is inclined 45 ° in the XY direction.

  The height detection unit 45 and the inclination detection unit 46 may measure the movement amount of the graphic in units of cells and obtain the movement amounts ΔX and ΔY based on the average value of the movement amount of the graphic in units of cells. Thereby, even if the position where the HHP 20 is placed on the screen 11 is shifted, the influence on the calibration can be reduced.

<Calibration process flow>
FIG. 21 is a diagram showing an overall flow of the calibration process. The left side of FIG. 21 shows the operation of the user or the operation of the display device 10, and the right side shows the operation of the HHP 20.

  When the user presses the power button of the HHP 20 (step S10), the measured values of the displacement of the HHP 20 in the height direction (Z-axis direction), the tilt in the XZ direction and the YZ direction, and the tilt in the XY direction are initialized ( Step S20). Subsequently, calibration processing is started (step S11), and the display device 10 is installed under the HHP 20 by the user. Subsequently, the display device 10 displays a fixed pattern image (step S13). For example, the display device 10 displays a bar-shaped figure as shown in FIG. 2B as a fixed pattern image. Subsequently, the user presses the calibration button 5 of the HHP 20 (step S14). The HHP 20 shifts to the ready state when the calibration button 5 is pressed.

  The HHP 20 determines whether it is in a ready state (step S21). If the HHP 20 has shifted to the ready state (step S21 Yes), the HHP 20 turns on the LED 6 (step S22). On the other hand, if the HHP 20 has not transitioned to the ready state (No at Step S21), the HHP 20 executes Step S21 again after a predetermined time.

  Subsequently, the HHP 20 captures a captured image on the sensor 30 (step S23). Subsequently, the HHP 20 counts the number of cells on one side of the captured image (step S24).

  Subsequently, the height detection unit 45 obtains the height (distance h in the Z-axis direction) from the current screen 11 from the number of cells on one side of the captured image (step S25). For example, the height detection unit 45 may obtain the height of the sensor 30 using the relationship table shown in FIG. Subsequently, the height detection unit 45 stores a correction coefficient corresponding to the resolution corresponding to the height in the memory 29 (step S26). The height detector 45 may store the relationship table shown in FIG. 11 in the memory 29 and use it instead of the correction coefficient.

  Subsequently, the inclination detection unit 46 calculates the current inclination in the XZ direction from the number of cells on one side of the captured image (step S27).

  The tilt in the XZ direction may be calculated using a method other than the method for calculating the current tilt in the XZ direction from the number of cells on one side of the captured image. For example, the inclination detection unit 46 may calculate the inclination in the XZ direction based on the amount of movement of the graphic 12 displayed on the screen 11 as in the example illustrated in FIG.

  Subsequently, the inclination detection unit 46 stores a correction coefficient corresponding to the inclination in the XZ direction in the memory 29 (step S28).

  Subsequently, the inclination detection unit 46 calculates the current inclination in the YZ direction from the number of cells on one side of the captured image (step S29). Subsequently, the inclination detecting unit 46 stores a correction coefficient corresponding to the inclination in the YZ direction in the memory 29 (step S30).

  Subsequently, the display device 10 moves the fixed pattern image after a predetermined time has elapsed since the calibration button 5 was pressed (step S15).

  Subsequently, the inclination detection unit 46 calculates the current inclination XY in the XY direction based on the movement amounts ΔX and ΔY of the fixed pattern image measured by the two sensors 30a and 30b (step S31). For example, the inclination detection unit 46 calculates the inclination θ in the XY directions based on the mathematical expression of Equation 1.

  The inclination detection unit 46 stores a correction coefficient corresponding to the calculated inclination θ in the XY direction in the memory 29 (step S32). For example, the inclination detection unit 46 may store sin θ and cos θ used in the mathematical expression (1) in the memory as correction coefficients.

  Subsequently, the HHP 20 turns off the LED 6 (step S33). Subsequently, when the HHP 20 is moved onto the print medium by the user, the HHP 20 performs print processing while referring to the accurate current position calculated by the position calculation circuit 32 using each correction coefficient stored in the memory 29. Is started (step S16).

  It should be noted that the height (Z) direction correction in steps S25 and S26, the tilt (XZ, YZ) direction correction in steps S27 to S30, and the plane (XY direction) correction in steps S31 and 32 are corrected. Among them, only correction of the deviation in the height (Z) direction may be performed. Further, only correction of the deviation in the inclination (XZ, YZ) direction in steps S27 to S30 may be performed. Only correction of displacement on the plane (XY direction) in steps S31 and S32 may be performed. However, it is preferable that all the three corrections are performed. Further, the order in which the above three corrections are performed is not limited to the order shown in FIG. 21 and may be any order.

<Calculation of movement component of sensor after movement>
FIG. 22 is a diagram for explaining a sensor position calculation method. In FIG. 22, the IJ recording head 24 before movement is shown on the left side, and the IJ recording head 24 after movement is shown on the right side. Sensors 30 a and 30 b are arranged at both ends of the IJ recording head 24. The IJ recording head 24 moves in the upper right direction, and the axis passing through the sensor 30a and the sensor 30b rotates dθ in the clockwise direction.

The initial position of the sensor 30a is (X ₀ , Y ₀ ), the initial position of the sensor 30b is (X ₁ , Y ₁ ), and the distance from the sensor 30a to the sensor 30b is L. Further, the rotational component of the axis passing through the sensor 30a and the sensor 30b before and after the movement is dθ, and the parallel movement component in the X-axis direction of the sensor 30a before and after the movement is ΔX ₀ , the parallel in the Y-axis direction. Let the moving component be ΔY ₀ . Further, the movement component in the X-axis direction detected by the sensor 30a before and after movement is referred to as dx _S0 , and the movement component in the Y-axis direction is defined as dy _S0 . Note that the movement components detected by the sensor 30a include dx _S0 and dy _S0 that include rotational components of the axis passing through the sensors 30a and 30b.

The position calculation circuit 32 calculates a rotation component and a parallel movement component from dx _S0 . The position calculation circuit 32 calculates the rotation component dθ based on the following mathematical formula.

The position calculation circuit 32 calculates the parallel movement components dX ₀ and dY ₀ based on the following mathematical formula.

dX ₀ = dx _{S 0} × cos θ + dy _{S 0} × sin θ
dY ₀ = −dx _{S 0} × sin θ + dy _{S 0} × cos θ (2)
<Correction of sensor position after movement>
Subsequently, the position calculation circuit 32 corrects dX ₀ and dY ₀ based on the correction coefficient calculated from the resolution of the sensor 30a. Specifically, a correction coefficient corresponding to the height of the sensor 30 is calculated in advance by the height detection unit 45 and stored in the memory 29. The position calculation circuit 32 corrects the parallel movement components dX ₀ and dY ₀ based on the correction coefficient stored in the memory 29.

For instance, the correction coefficient C _T is the actual amount of movement of HHP20, if the sensor 30 is a value obtained by dividing the movement amount detected, it corrects the parallel movement component dX ₀ and dY ₀ using the following equation. The corrected dX ₀ and dY ₀ are dX ₀ ′ and dY ₀ ′.

dX ₀ '= C _T × dX ₀
dY ₀ ′ = C _T × dY ₀ (3)
Subsequently, the position calculation circuit 32 corrects the moving components dX ₀ and dY ₀ based on the correction coefficient related to the XZ direction inclination calculated by the inclination detection unit 46 and the correction coefficient related to the YZ direction inclination. For example, when the coefficient of the amount of movement in the X-axis direction C _X, the coefficient of the amount of movement in the Y-axis direction and C _Y, corrects the parallel movement component dX ₀ and dY ₀ using the following equation.

dX ₀ '= C _X × dX ₀
dY ₀ ′ = C _Y × dY ₀ (4)
Subsequently, the position calculation circuit 32 corrects the moving components dX ₀ and dY ₀ by using correction coefficients (for example, sin θ and cos θ of the sensor 30a and the sensor 30b) related to the inclination in the XY direction in the equation (2). To do.

Subsequently, the position calculation circuit 32 adds the movement amounts dX ₀ and dY ₀ to the initial position (X ₀ , Y ₀ ) of the sensor 30 a (X ₀ + dX ₀ , Y ₀ + dY ₀ ), thereby moving the sensor 30 a. The subsequent position (X ₀ ′, Y ₀ ′) is calculated.

Subsequently, the position calculation circuit 32 substitutes the position (X ₀ ′, Y ₀ ′) after the movement of the sensor 30a and the angle θ between the line passing through the sensor 30a and the sensor 30b and the Y axis into the following equation. Then, the position (X ₁ ′, Y ₁ ′) after the movement of the sensor 30b is calculated.

X ₁ ′ = X ₀ ′ −L × sin θ
Y ₁ ′ = Y ₀ ′ −L × cos θ (5)
Note that the position calculation circuit 32 may calculate the position after the movement of the sensor 30b in the same manner as the sensor 30a.

<Calculation of the position of each nozzle>
FIG. 23 is a first diagram for explaining the calculation of the leading nozzle position. Nozzles 24a to 24f are arranged on a line segment connecting the sensor 30a and the sensor 30b. The position calculation circuit 32 calculates the exact position of each nozzle from the positional relationship between the sensors 30a and 30b corrected by the above processing and each nozzle.

When the distance from the sensor 30a to the IJ recording head 24 is a, the distance from the sensor 30a side end of the IJ recording head 24 to the head nozzle 24a is d, and the distance between the nozzles is e, the position calculation circuit 32 Finds the position (NZL ₁ _X, NZL ₁ _Y) of the _first nozzle 24a in the array by the following equation. Further, the position calculation circuit 32 obtains the rear nozzle 24f in the same manner as the nozzle 24a.

NZL ₁ _X = X ₀ − (a + d) × sin θ
NZL ₁ _Y = Y ₀ − (a + d) × cos θ (6)
FIG. 24 is a second diagram for explaining the calculation of the leading nozzle position. The nozzles 24A to 24F are not arranged on the line segment that connects the sensor 30a and the sensor 30b. When the arrangement of the nozzles 24a to 24f is n, the arrangement of the nozzles 24a to 24f is c, and the distance between the n and c is f, the position calculation circuit 32 determines the position of the first nozzle 24A in the arrangement c. (NZL ₁ _X, NZL ₁ _Y) is obtained by the following formula. Further, the position calculation circuit 32 obtains the rear nozzle 24F of the array c in the same manner as the nozzle 24A.

NZL _c-1 _X = X ₀ − (a + d) × sin θ + f × cos θ
NZL _c-1 — Y = Y ₀ − (a + d) × cos θ + f × sin θ (7)
FIG. 25 is a first diagram for explaining the calculation of the position of a nozzle located between the head and tail nozzles. The position calculation circuit 32 obtains the position of the Nth nozzle 24N (24b to f) from the head that is between the head and tail nozzles based on the positional relationship with the head and tail nozzles using the following formula.

NZL _{N_X} = XS + {(XE-XS) / (E-1)} * N
NZL _{N —} X = YS + {(YE−YS) / (E−1)} × N (8)
FIG. 26 is a second diagram for explaining the calculation of the position of the nozzle in the middle of the leading and trailing nozzles. For example, the position calculation circuit 32 can obtain the positions of the nozzles after the first nozzle based on the positions of the virtual nozzles existing on the extension line of the nozzle array. The position calculation circuit 32 previously calculates virtual nozzle positions (NZL_XE, NZL_YE) based on the distance e between the nozzles and the inclination θ of the nozzle arrangement with respect to the X-axis direction.

For example, 192 nozzles in the nozzle array has been arranged, the 257-th nozzle and the virtual nozzle, the position of the first nozzle _{24_1 (NZL_ XS, NZL_ YS)} , the position of the virtual nozzle 24_257 (NZL_ _XE, when the NZL_ _YE), the position of the N-th nozzle 24_N from the beginning in the middle of the head and tail nozzle by the following equation _{(NZL NX,} seek NZL _NY).

_{NZL NX = {NZL_ XS × (} 257-N) + NZL_ XE × (N-1)} ÷ 256
_{NZL NY = {NZL_ YS × (} 257-N) + NZL_ YE × (N-1)} ÷ 256 ··· (9)
[Embodiment 2]
In the first embodiment, it has been described that the calibration is performed before the user starts the printing process. However, the present invention is not limited to this, and the calibration may be performed in the manufacturing process of the HHP 20.

  The result of calibration executed in the manufacturing process of the HHP 20 may be held in the ROM 28, for example. For example, the correction coefficient related to the height of the sensor 30 measured by the height detection unit 45, the correction coefficient related to the inclination in the XZ direction and the YZ direction measured by the inclination detection unit 46, and the XY measured by the inclination detection unit 46 A correction coefficient related to the direction inclination is calculated and stored in the ROM 28.

  Thereby, the calibration process by the user can be omitted or simplified at the initial stage when the HHP 20 is started to operate, and the convenience for the user can be improved.

  Further, the height of the sensor 30 is measured, and when the height is such that the movement amount of the HHP 20 cannot be measured stably, the sensor 30 may be reattached or the sensor 30 may be replaced. That is, the calibration process may be executed in the test process of the HHP 20.

  For example, in the example illustrated in FIG. 12, the movement amount of the HHP 20 can be stably measured when the height of the sensor 30 is in the range of 2.0 mm to 3.0 mm. If it is out of the range of 3.0 mm, the sensor 30 may be reattached or the sensor 30 may be replaced.

  The HHP 20 is an example of an image forming apparatus. The sensor 30 is an example of a detection unit. The sensor I / F 42 is an example of a movement amount calculation unit. The height detection unit 45 and the inclination detection unit 46 are an example of an acquisition unit. The screen 11 is an example of surface information. Samp1 to 3 in FIG. 6B are examples of basic surface information. The position calculation circuit 32 is an example of a correction unit. Information regarding the height of the sensor 30 is an example of height information. The information about the tilt in the XZ direction and the YZ direction and the tilt in the XY direction is an example of the tilt information. Further, the height information (information about the height of the sensor 30) and the inclination information (information about the inclination in the XY directions) are examples of correction information.

  The figure 12 is an example of a predetermined pattern. A cell is an example of a unit image. The inclination in the XY direction is an example of an assembly angle. The ROM 28 is an example of a storage area. Further, the first direction is, for example, the X-axis direction, and the second direction is, for example, the Y-axis direction. The movement distance in the first direction is an example of the movement amount ΔX in the X-axis direction measured by the sensor 30. The movement distance in the second direction is an example of the movement amount ΔY in the Y-axis direction measured by the sensor 30.

DESCRIPTION OF SYMBOLS 10 Display device 23 IJ recording head drive circuit 25 Control part 26 OPU
28 ROM
29 Memory (DRAM)
30a, 30b Sensor 31 CPU
32 position calculation circuit 35 memory CTL
36 ROMCTL
37 ImageRAM
38 DMAC (CACHE)
39 Rotator 40 ASIC / FPGA
41 Interrupt controller 42 Sensor I / F
43 Print / Sensor Timing Generation Unit 44 IJ Recording Head Control Unit 45 Height Detection Unit 46 Inclination Detection Units 47 and 48 Bus

Special table 2010-535118 gazette

Claims (10)

An image forming apparatus for forming an image on a medium,
Detection means for reading the medium and acquiring surface information;
A movement amount calculation unit that calculates a movement amount of the image forming apparatus based on the acquired surface information;
An image forming apparatus comprising: a correcting unit that corrects the amount of movement based on basic surface information acquired by the detection unit reading a predetermined pattern. Further comprising an acquisition means for acquiring at least one of height information and inclination information of the detection means based on the basic surface information;
The image forming apparatus according to claim 1, wherein the correction unit corrects the movement amount based on at least one of the acquired height information and inclination information.   The acquisition unit acquires the gradient information of the detection unit based on a ratio between a length in the first direction and a length in a second direction of the predetermined pattern represented in the basic surface information. The image forming apparatus described.   The acquisition unit is based on a ratio of a movement distance in the first direction and a movement distance in the second direction of the predetermined pattern represented in the basic surface information when the image forming apparatus is scanned on the surface. The image forming apparatus according to claim 2, wherein inclination information of the detection unit is acquired.   The acquisition unit acquires the height information of the detection unit based on the granularity information of the predetermined pattern represented in the basic surface information or the resolution with respect to the movement amount detected by the detection unit. The image forming apparatus according to any one of the above.   The image forming apparatus according to claim 5, wherein the acquisition unit calculates and acquires height information of the detection unit based on the number of unit images corresponding to the predetermined pattern detected by the detection unit.   The image formation according to claim 5 or 6, wherein the acquisition unit acquires height information of the detection unit based on a pattern detected by the detection unit among a plurality of patterns having different granularities in the predetermined pattern. apparatus.   The said acquisition means acquires the height information of the said detection means based on the time from the detection start of the said predetermined pattern by the said detection means until the detection is completed. The image forming apparatus described in 1. A program executed by an image forming apparatus that forms an image on a medium,
Reading the medium by the detection means to obtain surface information;
Calculating a movement amount of the image forming apparatus based on the acquired surface information;
A program that causes the image forming apparatus to execute the step of correcting the amount of movement based on basic surface information acquired by the detection unit reading a predetermined pattern. A method of manufacturing an image forming apparatus for forming an image on a medium,
Calculating correction information used for correcting the movement amount of the image forming apparatus based on basic surface information acquired by a detection unit reading a predetermined pattern on a medium; and
Storing the correction information acquired in the calculating step in a storage area.