JP6717042B2 - Position detection device, droplet discharge device - Google Patents

Description

The present invention relates to a position detection device and a droplet discharge device.

2. Description of the Related Art A printer is known that conveys a sheet and ejects ink or the like at the timing when the sheet reaches an image forming position to form an image. On the other hand, with the downsizing of notebook PCs and the widespread use of smart devices such as smartphones, there is an increasing need for downsizing and portability of printer devices. Therefore, a printer downsized by removing the paper transport system from the printer device (hereinafter, referred to as HMP: handy mobile printer) is being put to practical use. Since the HMP is not equipped with a paper transport system, it can be moved manually by a person to scan the paper and eject ink.

The HMP detects its own position on the paper surface and ejects ink for forming an image corresponding to the position. As a mechanism for detecting this position, an HMP in which two navigation sensors are arranged on the bottom surface is conventionally known (for example, refer to Patent Document 1). The navigation sensor is a sensor that optically detects a minute edge on the paper surface to detect the amount of movement for each cycle time.

However, the conventional HMP has a problem that an accurate position cannot be detected if even one of the two navigation sensors has an abnormal output. For example, if the navigation sensor is protruding from the print medium or is floating from the print medium, the amount of movement output by the navigation sensor is not accurate. The HMP may detect that the amount of movement is abnormal and stop printing to prevent deterioration of print quality, which may cause an unfavorable situation for the user that the entire image data cannot be printed.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a position detection device capable of detecting a position even if an output of at least one navigation sensor is abnormal.

The present invention is a position detecting device for detecting a position of a mounted object on which a position detecting device is mounted on a moving surface, wherein N (N>2) moving amount detecting means for detecting a moving amount on the moving surface. And a first position calculating means for calculating the position using the movement amounts detected by the n (2≦n<N) movement amount detecting means selected based on the output of the movement amount detecting means. A second position calculation means for calculating a plurality of detection means positions of the movement amount detection means for one movement amount detection means using the movement amount detected by the movement amount detection means; Selection means for selecting n of the movement amount detection means based on a result of comparing the plurality of detection means positions of the amount detection means, and the first position calculation means includes the selection means. The position is calculated using the movement amounts detected by the arbitrary two movement amount detecting means out of the selected n pieces.

It is possible to provide a position detection device that can detect a position even if the output of at least one navigation sensor is abnormal.

It is an example of a diagram showing a navigation sensor included in the handy mobile printer. It is an example of a diagram schematically showing image formation by HMP. It is an example of a hardware configuration diagram of HMP. It is an example of a diagram illustrating a configuration of a control unit. It is an example of a configuration diagram of an image reading unit. It is a figure which shows the structural example of the hardware constitutions of a navigation sensor. It is an example of the figure explaining the detection method of the amount of movement by a navigation sensor. FIG. 3 is an example of a configuration diagram of an IJ recording head drive circuit. FIG. 6 is an example of a diagram illustrating nozzle positions and the like in an IJ recording head. It is an example of a diagram illustrating a method of calculating the coordinate system and position of the HMP. FIG. 6 is an example of a diagram for explaining how to determine a change amount dθ of a rotation angle of HMP that occurs during image formation. It is an example of a diagram for explaining the calculation of the position of the nozzle. It is a figure which shows the example of arrangement|positioning of the navigation sensor in HMP. It is an example of a functional block diagram of HMP20. It is an example of a flow chart explaining the operation procedure of the image data output device and HMP. It is an example of a diagram showing the position of the navigation sensor S ₀ calculated from the position of the navigation sensors S ₂ and S ₃ and the rotation angle θ.

Embodiments for carrying out the present invention will be described below with reference to the drawings.

<About the number of navigation sensors>
FIG. 1 is an example of a diagram showing a navigation sensor included in the handy mobile printer of this embodiment. The handy mobile printer (hereinafter referred to as HMP) in the figure has four navigation sensors S _{0 to} S ₃ . Note that the number and arrangement of navigation sensors are merely examples. The navigation sensors S _{0 to} S ₃ are sensors that output the movement amount for each sampling cycle. The amount of movement can be detected with one navigation sensor, but the outputs (movement amounts) of at least two navigation sensors are required to detect the posture of the HMP. The HMP detects the position on the print medium 12 from the movement amount and the posture.

In FIG. 1A, the four navigation sensors S _{0 to} S ₃ scan the print medium 12. In this case, the HMP may use the outputs of any two navigation sensors (eg, S ₀ and S ₁ , S ₂ and S ₃ ) to detect the position. On the other hand, in FIG. 1B, the two navigation sensors S ₂ and S ₃ protrude from the paper surface. In this case, the HMP 20 detects that the navigation sensors S ₂ and S ₃ have protruded from the print medium 12, and detects the position on the print medium from the movement amounts and the postures of the navigation sensors S ₀ and S ₁ .

In FIG. 1B, it is clear that the navigation sensors S ₂ and S ₃ protrude from the print medium 12, but it is often difficult to identify the navigation sensors S ₂ and S ₃ that the HMP protrudes from. Therefore, HMP calculates a plurality of positions for one of the navigation sensors _S 0 to S _3, a reliable position is determined to be the position of the navigation sensor _S 0 to S _3. By doing so, even when the navigation sensor that the HMP protrudes cannot be specified, it is possible to determine the highly reliable navigation sensor and its position and continue printing.

Therefore, by having three or more navigation sensors (N (N>2)), as long as there are two or more navigation sensors on the print medium (even if one or more navigation sensors extend beyond the print medium 12). The HMP can continue printing by suppressing deterioration of print quality.

<About terms>
The mounted object is an object on which the position detecting device is mounted. It may be an object whose position can be detected on the moving surface. For example, the HMP 20 is an example of the mounted object. Further, since the position detecting device can detect the distance moved, the distance measuring device can be an example of the mounted object.

The moving surface may be a surface on which the HMP 20 can move, and includes a curved surface as well as a flat surface. Specifically, the print medium 12 is exemplified, but the present invention is not limited to this.

The output of the movement amount detection means (navigation sensor) is information by which the reliability of the movement amount detection means or the movement amount can be evaluated. In the present embodiment, a description will be given by taking sensor reliability information described later and a plurality of positions of one navigation sensor calculated from the movement amount as an example.

Calculating the position means obtaining information about the position by performing calculation on some data, and detecting the position means obtaining information about the position regardless of the process. However, both are the same in that information about the position is obtained, and in the present embodiment, the calculation of the position and the detection of the position are not strictly distinguished.

Further, in the present embodiment, image formation, recording, printing, printing, printing, modeling, etc. are synonymous.

<Image formation by HMP20>
FIG. 2 is an example of a diagram schematically showing image formation by the HMP 20. Image data is transmitted to the HMP 20 from the image data output device 11 such as a smartphone or a PC (Personal Computer). The user holds the HMP 20 and scans it in a freehand manner so as not to lift it up from the print medium 12 (for example, fixed-size paper or notebook).

The HMP 20 detects the position by any two of the navigation sensors S _{0 to} S ₃ as described later, and when the HMP 20 moves to the target ejection position, it ejects the ink of the color to be ejected at the target ejection position. Since the place where ink has already been ejected is masked (since it is not the subject of ink ejection), the user can form an image by scanning the HMP 20 on the print medium 12 in any direction.

The reason why the HMP 20 does not float from the print medium 12 is that the navigation sensors S _{0 to} S ₃ detect the movement amount by using the reflected light from the print medium 12. When the HMP 20 floats up from the print medium 12, the reflected light cannot be detected and the movement amount cannot be detected. Further, even when the navigation sensors S _{0 to} S ₃ are projected from the print medium 12, the reflected light may not be detected depending on the thickness of the print medium 12, or the position may be displaced even if the reflected light can be detected.

Therefore, in the present embodiment, it is preferable that at least two navigation sensors (two of S _{0 to} S ₃ ) are scanned on the print medium 12.

<Structure example>
FIG. 3 shows an example of a hardware configuration diagram of the HMP 20. The HMP 20 is an example of an image forming apparatus that forms an image on the print medium 12. The entire operation of the HMP 20 is controlled by the control unit 25, and the control unit 25 controls the communication I/F 27, the IJ recording head drive circuit 23, the OPU 26, the ROM 28, the DRAM 29, and the four navigation sensors 30 (S distinguish them to distinguish them from each other). _{0 to} S ₃ ) are electrically connected. Since the HMP 20 is driven by electric power, it has a power supply 22 and a power supply circuit 21. The electric power generated by the power supply circuit 21 is, for example, by wiring indicated by a dotted line 22a, 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 four navigation sensors. It is supplied to 30. The number of navigation sensors 30 may be three or more.

The power source 22 is mainly a battery. A solar cell, a commercial power supply (AC power supply), a fuel cell, or the like may be used. The power supply circuit 21 distributes the power supplied by the power supply 22 to each unit of the HMP 20. Further, the voltage of the power supply 22 is stepped down or boosted to a voltage suitable for each part. When the power supply 22 is chargeable by a battery, the power supply circuit 21 detects the connection of the AC power supply and connects it to the battery charging circuit to charge the power supply 22.

The communication I/F 27 receives image data from the image data output device 11 such as a smartphone or a PC (Personal Computer). The communication I/F 27 is a communication device compatible with a communication standard such as wireless LAN, Bluetooth (registered trademark), NFC (Near Field Communication), infrared ray, 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 controls hardware of the HMP 20, drive waveform data of the IJ recording head 24 (data that defines a voltage change for ejecting droplets), initial setting data of the HMP 20, and the like.

The DRAM 29 is used to store the image data received by the communication I/F 27 and to store the firmware expanded from the ROM 28. Therefore, it is used as a work memory when the CPU 33 executes the firmware.

The navigation sensor 30 is a sensor that detects the amount of movement of the HMP 20 every predetermined cycle time. Although the four navigation sensors 30 have the same function, it is assumed that there is no problem in the description of the present embodiment even if there are differences. The navigation 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 12. When the HMP 20 is scanned over the print medium 12, minute edges of the print medium 12 are detected one after another (imaged) and the distance between the edges is analyzed to obtain the movement amount. In this embodiment, four navigation sensors 30 are mounted on the bottom surface of the HMP 20. A multi-axis acceleration sensor may be used as the navigation sensor 30, and the HMP 20 may detect the position of the HMP 20 using only the acceleration sensor. A gyro sensor may be provided to detect the rotation angle with respect to the axis perpendicular to the print medium.

The OPU (Operation panel Unit) 26 has an LED for displaying the state of the HMP 20, a switch for the user to instruct the HMP 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 uses the above driving waveform data to generate a driving waveform (voltage) for driving the IJ recording head 24. A drive waveform can be generated according to the size of ink droplets and the like.

The IJ recording head 24 is a head for ejecting ink. Although four colors of CMYK ink can be ejected in the figure, it is also possible to eject a single color or five or more colors. A plurality of nozzles 61 for ejecting ink are arranged in one row (two or more rows may be arranged) for each color. Further, the ink ejection method may be a piezo method, a thermal method, or another method such as an electrostatic method.

The IJ recording head 24 is a functional component that ejects and ejects liquid from the nozzle 61. The ejected liquid may have any viscosity or surface tension that can be ejected from the IJ recording head 24, and is not particularly limited, but the viscosity becomes 30 mPa·s or less at room temperature and normal pressure, or by heating and cooling. It is preferably one. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional compounds such as polymerizable compounds, resins and surfactants, biocompatible materials such as DNA, amino acids, proteins and calcium. , Solutions, suspensions, emulsions, etc. containing edible materials such as natural pigments, etc., such as ink-jet inks, surface treatment solutions, components of electronic devices and light-emitting devices, and formation of electronic circuit resist patterns. It can be used for applications such as a working fluid and a three-dimensional modeling material fluid.

The control unit 25 has a CPU 33 and controls the entire HMP 20. Based on the movement amount and the rotation angle detected by the navigation sensor 30, the control unit 25 determines the position of each nozzle of the IJ recording head 24, the determination of the image to be formed in accordance with the position, the ejection nozzle feasibility determination described below, and the like. To do. 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 has a SoC 50 and an ASIC/FPGA 40. The SoC 50 and the ASIC/FPGA 40 communicate with each other via the buses 46 and 47. This means that the ASIC/FPGA 40 may be designed by any mounting technology, and may be configured by another mounting technology other than the ASIC/FPGA 40. Further, the SoC 50 and the ASIC/FPGA 40 may be configured by one chip or substrate without using different chips. Alternatively, it may be mounted with three or more chips or substrates.

The SoC 50 has functions such as a CPU 33, a position calculation circuit 34, a memory CTL (controller) 35, and a ROM CTL (controller) 36, which are connected via a bus 47. The components included in the SoC 50 are not limited to these.

The ASIC/FPGA 40 has an image reading unit 38, an interrupt controller 41, a navigation sensor I/F 42, a print/sensor timing generation unit 43, and an IJ recording head control unit 44, which are connected via a bus 46. ing. The components included in the ASIC/FPGA 40 are not limited to these.

The CPU 33 executes the firmware (program) expanded from the ROM 28 to the DRAM 29 and controls the operations of the position calculation circuit 34, the memory CTL 35, and the ROM CTL 36 in the SoC 50. It also controls the operations of the image reading unit 38, the interrupt controller 41, the navigation sensor I/F 42, the print/sensor timing generation unit 43, the IJ recording head control unit 44, etc. in the ASIC/FPGA 40.

The position calculation circuit 34 calculates the position (coordinate information) of the HMP 20. Specifically, the position calculation circuit 34, four using at least one moving amount of the navigation sensors S ₀ to S _3, based on two moving amount of the four navigation sensor S ₀ to S ₃ position ( The position of the HMP 20 is calculated based on the rotation angle). Strictly speaking, the position of the HMP 20 is the position of the nozzle 61, but if the position of the navigation sensor 30 is known, the HMP 20 can calculate the position of the nozzle 61. The position calculation circuit 34 also calculates a target ejection position. The position calculation circuit 34 may be implemented by the CPU 33 as software.

The position of the navigation sensor 30 is calculated based on, for example, a predetermined origin (the initial position of the HMP 20 when image formation is started), as described later. Further, the position calculation circuit 34 estimates the acceleration and the moving direction based on the difference between the past position and the newest position, and predicts the position at the next ink ejection timing, for example. By doing so, ink can be ejected while suppressing the delay with respect to the 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 33, and sends the acquired image data to the ASIC/FPGA 40.

The ROM CTL 36 is an interface with the ROM 28, requests the ROM 28 for data, and sends the acquired data to the CPU 33 and the ASIC/FPGA 40.

The CPU inputs the position of the navigation sensor 30 calculated by the position calculation circuit 34 to the image reading unit 38. The image reading unit 38 calculates the position of each nozzle based on the relative position between the navigation sensor 30 and the nozzle 61. Then, the image data corresponding to the position of the nozzle is read from the DRAM, and the image data is arranged and transmitted in the arrangement order requested by the IJ recording head 24.

The print/sensor timing generation unit 43 notifies the navigation sensor I/F of the timing at which the navigation sensor I/F 42 reads information, and notifies the IJ recording head control unit 44 of the drive timing. The cycle of information reading timing is longer than the cycle of ink ejection timing.

The IJ recording head controller 44 ejects ink based on the image data at the timing notified by the print/sensor timing generator 43. The IJ recording head drive circuit 23 uses the drive waveform data corresponding to the control signal as described above to generate a drive waveform (voltage). The IJ recording head control unit 44 determines whether or not the ejection nozzle is possible, and determines that the ink is ejected if there is a target ejection position at which the ink should be ejected and that it is not ejected if there is no target ejection position.

The navigation sensor I/F 42 communicates with the navigation sensor 30, receives the movement amounts ΔX′ and ΔY′ (these will be described later) as information from the navigation sensor 30, and stores the values in a register. The information from the navigation sensor 30 also has a status notification function (including sensor reliability information described later) indicating whether or not the reading of reflected light is good.

The interrupt controller 41 detects that the navigation sensor I/F 42 has completed communication with the navigation sensor 30, and outputs an interrupt signal for notifying the SoC 50 of the completion. The CPU 33 acquires ΔX′ and ΔY′ stored in the register by the navigation sensor I/F 42 by this interrupt.

FIG. 5 shows an example of a configuration diagram of the image reading unit 38. The image reading unit 38 has a CPU I/F 381, a nozzle position generation unit 382, an address generation unit 383, an output I/F 384, a data storage unit 385, and a table management unit 386. The CPU I/F 381 is a circuit that serves as an interface with the CPU 33. The CPU I/F 381 receives various settings such as the resolution of the image in the width direction and the resolution of the image in the vertical direction from the CPU 33. Further, the ejection timing is acquired from the IJ recording head controller 44, and the position of the navigation sensor 30 at the ejection timing is received from the CPU 33.

The nozzle position generator 382 generates the position of each nozzle from the position of the navigation sensor 30. Each time the position of the navigation sensor 30 is received, positions corresponding to the number of nozzles are generated and output to the address generation unit 383. In addition, the nozzle position generation unit 382 outputs the valid/invalid flag of each nozzle in accordance with the print mode, the number of ejection nozzles limitation, and the like.

The address generating unit 383 generates a memory address in which the data is stored, based on the position of each nozzle obtained by the nozzle position generating unit 382.

The data storage unit 385 stores the image data acquired from the memory CTL35. In addition, the data to be written in the DRAM 29 is temporarily stored.

The table management unit 386 associates the address generated by the address generation unit 383 with the data stored in the data storage unit 385. The table management unit 386 outputs the data associated with the address generated by the address generation unit 383 to the address generation unit 383.

The output I/F 384 converts the image data acquired from the table management unit 386 into a format required by the IJ recording head control unit 44. Further, the image data is buffered, and the image data is output to the IJ recording head controller 44 in response to a request.

<About navigation sensors>
FIG. 6 is a diagram illustrating a configuration example of the hardware configuration of the navigation sensor. The navigation sensors S _{0 to} S ₃ have the same structure. The navigation sensor 30 has a host I/F 301, an image processor 302, an LED driver 303, two lenses 304 and 306, and an image array 305. The LED driver 303 has an LED and a control circuit integrated with each other, and emits LED light according to a command from the image processor 302. The image array 305 receives the reflected light of the LED light from the print medium 12 via the lens 304. The two lenses 304 and 306 are installed so as to be optically focused on the surface of the print medium 12.

The image array 305 includes a photodiode having sensitivity to the wavelength of LED light, and generates image data from the received LED light. The image processor 302 acquires the image data and calculates the moving distance (ΔX′, ΔY′) of the navigation sensor from the image data. The image processor 302 outputs the calculated moving distance to the control unit 25 via the host I/F 301.

Light emitting diodes (LEDs) used as light sources are useful when using a print medium 12 having a rough surface, such as paper. This is because when the surface is rough, a shadow is generated, and it is possible to accurately calculate the movement distances in the X-axis direction and the Y-axis direction using the shadow as a characteristic portion. On the other hand, for the print medium 12 having a smooth or transparent surface, a semiconductor laser (LD) that generates a laser beam can be used as a light source. This is because a characteristic portion can be formed by forming, for example, a striped pattern on the print medium 12 with the semiconductor laser, and the movement distance can be accurately calculated based on the characteristic portion.

Next, the operation of the navigation sensor 30 will be described with reference to FIG. FIG. 7 is a diagram illustrating a method of detecting the amount of movement by the navigation sensor 30. The light emitted by the LED driver 303 is emitted to the surface of the print medium 12 via the lens 306. The surface of the print medium 12 has minute irregularities of various shapes as shown in FIG. Therefore, various shapes of shadows are generated.

The image processor 302 receives the reflected light via the lens 304 and the image array 305 at every predetermined sampling timing, and acquires the image data 310. The image processor 302 converts the image data 310 generated as shown in FIG. 7B into a matrix in a prescribed resolution unit. That is, the image data 310 is divided into a plurality of rectangular areas. Then, the image processor 302 compares the image data 310 obtained at the previous sampling timing with the image data 310 obtained at the current sampling timing to detect the number of rectangular areas to which the image data 310 has moved, It is calculated as the moving distance. It is assumed that the HMP 20 moves in the ΔX direction shown in FIG. 7B. Comparing the image data 310 at t=0 and t=1, the shape at the right end matches the shape at the center. Therefore, since the shape moves in the −X direction, it can be seen that the HMP 20 has moved by one square in the X direction. The same applies to the times t=1 and t=2.

<IJ recording head drive circuit>
FIG. 8 is an example of a configuration diagram of the IJ recording head drive circuit 23. First, the IJ recording head 24 includes a plurality of nozzles 61, and each nozzle 61 is provided with an actuator. The actuator may be either a thermal type or a piezo type. In the thermal system, heat is applied to the ink in the nozzle to expand the ink, and the expansion causes ink droplets to be ejected from the nozzle 61. The piezo method is a method in which an ink droplet is ejected by pushing the nozzle wall by a piezoelectric element and pushing out the ink inside.

The IJ recording head drive circuit 23 includes an analog switch 231, a level shifter 232, a gradation decoder 233, a latch 234, and a shift register 235. The IJ print head control unit 44 sends to the IJ print head drive circuit 23 the image data SD, which is serial data for the number of nozzles 61 of the IJ print head 24 (the same number of actuators), by the image data transfer clock SCK. Transfer to the shift register 235.

When the transfer is completed, the IJ recording head control unit 44 stores each image data SD in the latch 234 provided for each nozzle according to the image data latch signal SLn.

After latching the image data SD, the IJ recording head controller 44 outputs a head drive waveform Vcom for ejecting ink droplets of each gradation value from each nozzle to the analog switch 231. At this time, the IJ recording head control unit 44 gives the head drive mask pattern MN as a gradation control signal to the gradation decoder 233, and selects the head drive mask pattern MN according to the timing of the drive waveform. Make a transition.

The gradation decoder 233 logically operates the gradation control signal and the latched image data, and the level shifter 232 boosts the logical level voltage signal obtained by the logical operation to a voltage level capable of driving the analog switch 231.

The analog switch 231 receives the boosted voltage signal and turns it on/off, so that the drive waveform VoutN supplied to the actuator of the IJ recording head becomes different for each nozzle. The IJ recording head 24 ejects ink droplets based on this drive waveform to form an image on the print medium 12.

It should be noted that the configuration and the description thereof in FIG. 8 are configurations generally adopted in an inkjet printer. As long as the ink droplets can be ejected, the configuration is not limited to that shown in FIG.

<Regarding the nozzle position in the IJ recording head>
Next, the nozzle position and the like in the IJ recording head 24 will be described with reference to FIG. FIG. 9A is an example of a plan view of the HMP 20. FIG. 9B is an example of a diagram for explaining only the IJ recording head 24. The surface shown is the surface facing the print medium 12.

The HMP 20 of this embodiment has two navigation sensors S ₀ . The length between the two navigation sensors S ₀ , S ₁ is the distance L. The longer the distance L, the better. This is because the longer the distance L is, the smaller the minimum rotation angle θ that can be detected becomes, and the error in the position of the HMP 20 becomes smaller.

The distances from the navigation sensor 30 to the IJ recording head 24 are distances a and b, respectively. The distance a and the distance b may be equal to each other or may be zero (in contact with the IJ recording head 24). Further, when there is only one navigation sensor 30, the navigation sensor S ₀ is arranged at an arbitrary position around the IJ recording head 24. Therefore, the positions of the navigation sensors S ₀ and S ₁ shown are examples. However, since the distance between the IJ recording head 24 and the navigation sensors S ₀ and S ₁ is short, it is easy to reduce the size of the bottom surface of the HMP 20.

As shown in FIG. 9B, the distance from the end of the IJ recording head 24 to the first nozzle 61 is the distance d, and the distance between adjacent nozzles is the distance e. The values of a to e are stored in the ROM 28 or the like in advance.

If the position calculation circuit 34 or the like calculates the position of the navigation sensor S ₀ , the position calculation circuit 34 can calculate the position of the nozzle 61 using the distance a (distance b), the distance d, and the distance e.

<Regarding the position of the HMP 20 on the print medium 12>
FIG. 10 is an example of a diagram for explaining a method of calculating the coordinate system and the position of the HMP 20. In this embodiment, the horizontal direction of the print medium 12 is set to the X axis, and the vertical direction is set to the Y axis. The origin is the position of the navigation sensor S ₀ when the image formation is started. These coordinates will be referred to as print medium coordinates. On the other hand, the navigation sensor S ₀ outputs the movement amount on the coordinate axes (X′ axis, Y′ axis) of FIG. 11. That is, the movement amount is output with the arrangement direction of the nozzles 61 as the Y′ axis and the direction orthogonal to the Y′ axis as the X′ axis.

As shown in FIG. 9A, a case where the HMP 20 rotates clockwise θ with respect to the print medium 12 will be described as an example. It is considered difficult for the user to scan the HMP 20 with respect to the coordinates of the print medium, and it is considered that a non-zero θ occurs. If it is not rotating at all, X=X' and Y=Y'. However, when the HMP 20 rotates by the rotation angle θ with respect to the print medium 12, the output of the navigation sensor S ₀ and the actual position of the HMP 20 on the print medium 12 do not match. The rotation angle θ is positive in the clockwise direction, X and X′ are positive in the right direction, and Y and Y′ are upward in the positive direction.

FIG. 10A is an example of a diagram illustrating the X coordinate of the HMP 20. FIG. 10A shows the correspondence between the movement amounts ΔX′, ΔY′ and X, Y detected by the navigation sensor S ₀ when the HMP 20 having the rotation angle θ moves in the same rotation angle θ only in the X direction. .. Since the relative positions of the two navigation sensors S ₀ and S ₁ are fixed, the outputs (movement amounts) of the two navigation sensors S ₀ and S ₁ are the same. The X coordinate of the navigation sensor S ₀ is X1+X2, and X1+X2 is obtained from ΔX′, ΔY′ and the rotation angle θ.

FIG. 10B shows the correspondence between the movement amounts ΔX′, ΔY′ and X, Y detected by the navigation sensor S ₀ when the HMP 20 having the rotation angle θ moves only in the Y direction with the same rotation angle θ. .. The Y coordinate of the navigation sensor S ₀ is Y1+Y2, and Y1+Y2 is obtained from −ΔX′, ΔY′ and the rotation angle θ.

Therefore, when the HMP 20 moves in the X direction and the Y direction with the rotation angle θ, ΔX′ and ΔY′ output by the navigation sensor S ₀ can be converted into X and Y of the print medium coordinates as follows.
X=ΔX′ cos θ+ΔY′ sin θ (1)
Y=-ΔX'sinθ+ΔY'cosθ (2)
<<Detection of rotation angle θ>>
A method of calculating the rotation angle θ using the movement amounts output by the navigation sensors S ₀ and S ₁ will be described with reference to FIG. 11. FIG. 11 is an example of a diagram illustrating how to determine the amount of change dθ in the rotation angle of the HMP 20 that occurs during image formation. The rotation angle change amount dθ is calculated using the movement amount ΔX′ detected by the two navigation sensors S ₀ and S ₁ (ΔY′ may be used). The movement amount ΔX′ ₀ detected by the navigation sensor S _{0 on} the upper side of the print medium 12 and the movement amount ΔX′ ₁ detected by the navigation sensor S ₁ are set. Note that in FIG. 11, the already obtained rotation angle is θ.

When the HMP 20 rotates dθ while moving in parallel, the movement amounts ΔX′0 and ΔX′1 do not match. However, since both outputs are movement amounts in the direction perpendicular to the straight line connecting the two navigation sensors S ₀ and S ₁ , the difference between the movement amounts ΔX′0 and ΔX′1 is obtained as “ΔX′0−ΔX′1”. be able to. This difference is a value caused by the HMP 20 rotating by dθ. Further, since “ΔX′0−ΔX′1”, L, and dθ have the relationship shown in FIG. 11, dθ can be expressed as follows.
dθ=arcsin{(ΔX'0-ΔX'1)/L} (3)
The rotation angle θ can be obtained by the position calculation circuit 34 integrating the dθ. As shown in equations (1) and (2), the HMP 20 can detect the position using the rotation angle θ. Further, as can be seen from the equation (3), it is preferable to increase the distance L in order to detect a smaller dθ.

<Nozzle position>
FIG. 12A is an example of a diagram for explaining the calculation of the nozzle position. If even one position of the navigation sensor is known and the rotation angle θ is known, the nozzle position generation unit 382 can calculate the position of each nozzle 61. The nozzle 61-1 of FIG. 12A will be described as an example. The navigation sensors S ₂ and S ₃ are omitted in FIG. The distance between the navigation sensor S ₀ and the IJ recording head 24 is a, and the distance from the end of the IJ recording head 24 to the nozzle 61-1 is d. The rotation angle with respect to the axis perpendicular to the print medium 12 is θ. From these, the coordinates (X, Y) of the nozzle 61-1 can be obtained.

X=X0-(a+d)×sin θ
Y=Y0-(a+d)×cos θ
Further, FIG. 12B is a diagram for explaining the position of the nozzle 61 which is not on the straight line connecting the two navigation sensors S ₀ and S ₁ . In the present embodiment, since the four navigation sensors S _{0 to} S ₃ are arranged in the HMP 20, the nozzle rows Y and C are not on the straight line connecting the _two navigation sensors S ₀ and S ₁ or S ₂ and S _3. There is. Further, in the case of the HMP 20 that forms a color image, depending on the nozzle rows Y and C, it may not be on the straight line connecting the _two navigation sensors S ₀ and S ₁ or S ₂ and S ₃ .

When the distance between the nozzle row Y and the nozzle row C is f, the coordinates of the nozzle 61-1c of the nozzle row C in FIG. 12B can be obtained as follows.

X=X0-(a+d)×sin θ+ f×cos θ
Y=Y0-(a+d)×cos θ- f×sin θ
<Example of arrangement of four navigation sensors>
FIG. 13 is a diagram showing an arrangement example of the navigation sensors S _{0 to} S ₁ in the HMP 20 of this embodiment. The HMP 20 includes the number of navigation sensors required for calculating the nozzle position or more, and calculates the nozzle position using the output from any number of the navigation sensors among the plurality of navigation sensors.

Since the number of navigation sensors required for position calculation is two, the HMP20 is equipped with three or more navigation sensors. The HMP 20 adopts two highly reliable navigation sensors from among them, and calculates the rotation angle θ using the movement amounts of these two navigation sensors. Thereby, even if there is an abnormality in the output of some navigation sensors, it is possible to select an appropriate navigation sensor and calculate the nozzle position.

The HMP of FIG. 13 is equipped with four navigation sensors and is arranged at four corners of the IJ recording head 24. The positions of the navigation sensors S _{0 to} S ₃ are not limited to those shown in the figure. However, the navigation sensors S ₀ , S ₁ , S ₂ , S ₃ are preferably adjacent to the IJ recording head 24. Since the distance between the IJ recording head 24 and the navigation sensors S ₀ , S ₁ , S ₂ , S ₃ is short, the printable range of the print medium 12 is wide. This is because the nozzle 61 and the two navigation sensors (there are six ways as described later) need to be present on the print medium 12.

In addition, it is preferable that the distance between the two navigation sensors (there are 6 ways) is long. This is because the interval (L in FIG. 11) between the two navigation sensors (there are 6 types) influences the resolution of the rotation angle θ (a smaller rotation angle change amount dθ can be detected).

Therefore, as shown in the drawing, the navigation sensors S ₀ , S ₁ and S ₂ , S ₃ are arranged at intervals of the same length as the IJ recording head 24, and the direction perpendicular to the nozzle row is the width of the IJ recording head 24. It is preferable that the navigation sensors S ₀ and S ₁ and S ₂ and S ₃ are arranged at intervals of approximately the same length.

<About HMP function>
FIG. 14 shows an example of a functional block diagram of the HMP 20. The HMP 20 has an abnormality detection unit 51, a sensor position determination unit 52, and a sensor position correction unit 53. These are functions or means obtained by the CPU 33 shown in FIG. 4 expanding the firmware (program) stored in the ROM 28 in the DRAM 29 and executing it.

The abnormality detection unit 51 is realized by the CPU 33 and the like, and excludes the navigation sensor, which may include an abnormal value in the movement amount, from the target of position calculation based on the sensor reliability information. The sensor reliability information is information regarding the reliability of the movement amount output by the navigation sensors S _{0 to} S ₃ , and the navigation sensor I/F 42 can acquire the movement amount together with the navigation sensors S _{0 to} S ₃ . For example, the sensor reliability information includes the intensity of reflected light received by the image array 305, the number of edges (feature points) detected by the image processor 302, and the shutter time of the image array 305. The values of these deteriorate when the HMP 20 floats from the print medium 12. The intensity of reflected light decreases, the number of edges (feature points) decreases, and the shutter time increases. When the range of the appropriate value is determined and is not included in the appropriate value, the abnormality detection unit 51 excludes the navigation sensor that is not suitable. Since such information relates to the surface quality of the print medium, it may be called a surface quality value. Furthermore, the abnormality detection unit 51 may exclude navigation sensors whose movement amount is equal to or greater than a threshold value. This is because when the movement amount exceeds the threshold value at the general scanning speed of the user, the navigation sensors S _{0 to} S ₃ may stick out from the print medium 12 or float.

The sensor position determination unit 52 is realized by the CPU 33 and the like. The position of one navigation sensor 30 is calculated by the movement amount of one set of navigation sensors, but when there are four navigation sensors S _{0 to} S ₃ , the same position of one navigation sensor is calculated in a plurality of sets. .. The sensor position determination unit 52 determines the median value of a plurality of positions of one navigation sensor or the average value excluding the maximum value and the minimum value as the position of the navigation sensor. Further, the count values of the two navigation sensors used to calculate the position of the navigation sensor are increased, and the two navigation sensors are determined based on the count values. This makes it possible to determine two highly reliable navigation sensors and calculate the rotation angle.

The sensor position correction unit 53 is realized by the CPU 33 and the like, and uses the positions of the sensors (two) adopted for position calculation to correct the positions of the navigation sensors (two) not adopted for position calculation. ..

<Operation procedure>
FIG. 15 is an example of a flowchart explaining the operation procedure of the image data output device 11 and the HMP 20. First, the user presses the power button of the image data output device 11 (U101). The image data output device 11 accepts it, and is activated by being supplied with power from a battery or the like.

The user selects an image to be output by the image data output device 11 (U102). The image data output device 11 receives selection of an image. Document data of software such as a word processing application may be selected as an image, or image data such as JPEG may be selected. If necessary, the printer driver may change data other than the image data into an image.

The user performs an operation of printing the selected image with the HMP 20 (U103). The HMP 20 receives a request to execute a print job. Image data is transmitted to the HMP 20 in response to a print job request.

The user holds the HMP 20 and determines the initial position on the print medium 12 (for example, a notebook) (U104).

Then, the user presses the print start button of the HMP 20 (U105). The HMP 20 receives the press of the print start button.

The user freely scans the HMP 20 for sliding on the print medium 12 (U106).

Next, the operation of the HMP 20 will be described. The following operation is performed by the CPU 33 executing the firmware.

The HMP20 is also activated when the power is turned on. The CPU 33 of the HMP 20 initializes the hardware elements of FIGS. 3 and 4 built in the HMP 20 (S101). For example, the register of the navigation sensor I/F 42 is initialized, or the timing value is set in the print/sensor timing generation unit 43. Also, communication between the HMP 20 and the image data output device 11 is established.

The CPU 33 of the HMP 20 determines whether or not the initialization is completed, and if it is not completed, this determination is repeated (S102).

When the initialization is completed (Yes in S102), the CPU 33 of the HMP 20 informs the user that printing is possible, for example, by turning on the LED of the OPU 26 (S103). As a result, the user recognizes that the printing is possible and requests execution of the print job as described above.

In response to the print job execution request, the communication I/F 27 of the HMP 20 receives the input of the image data from the image data output device 11, and notifies the user that the image is input by blinking the LED of the OPU 26 (S104). ).

When the user determines the initial position of the HMP 20 on the print medium 12 and presses the print start button, the OPU 26 of the HMP 20 accepts this operation, and the CPU 33 causes the navigation sensor I/F 42 to read the position (S105). Thus, the navigation sensor I / F 42 communicates with the navigation sensors _S 0 to S _3, storing etc. obtains the amount of movement navigation sensors _S 0 to S ₃ detects register (S1001). The CPU 33 reads the amount of movement from the navigation sensor I/F 42.

Even if the movement amount acquired immediately after the user presses the print start button is zero, but is not zero, the CPU 33 stores it in the register of the DRAM 29 or the CPU 33, for example, as the initial position of the coordinate (0,0) (S106). ..

Further, when the initial position is acquired, the print/sensor timing generation unit 43 starts timing generation (S107). The print/sensor timing generation unit 43 instructs the navigation sensor I/F 42 of the timing when the acquisition timing of the movement amount of the navigation sensor S ₀ set in the initialization is reached. This is periodically performed, and becomes the above sampling period.

The CPU 33 of the HMP 20 determines whether or not it is time to acquire the movement amount and the angular velocity information (S108). This determination is performed by the notification from the interrupt controller 41, but it may be determined by the CPU 33 counting the same timing as the print/sensor timing generation unit 43.

At the timing of acquiring the movement amount and the angular velocity information, the CPU 33 of the HMP 20 acquires the movement amounts of the four navigation sensors S _{0 to} S ₃ from the navigation sensor I/F 42 (S109). As described above, the navigation sensor I/F 42 acquires the movement amount from the navigation sensors S _{0 to} S ₃ at the timing generated by the print/sensor timing generation unit 43.

Next, the abnormality detection unit 51 excludes the navigation sensor having an abnormal output from the position calculation target (S109-2). As described above, the navigation sensors S _{0 to} S ₃ whose sensor reliability information and movement amount are less than the threshold value are excluded. At this time, if the number of unexcluded navigations is 1 or less, an error or the like is displayed on the OPU 26 and the process ends. Alternatively, the number of navigation sensors excluded by the abnormality detection unit 51 may be limited so that the number of navigations not excluded is 2 or more.

Next, the position calculation circuit calculates the current position from the position (X, Y) calculated in the previous sampling cycle and the movement amount (ΔX′, ΔY′) acquired in the current sampling cycle, and the storage unit 59. To be stored (S109-3). In the present embodiment, the maximum number of navigation sensors is four. Therefore, the number of combinations of the navigation sensors S _{0 to} S ₃ used for calculating the position is the number when selecting two from four (that is, six ways).
Calculated from the movement amount of navigation sensors S ₀ and S ₁ Calculated from the movement amount of navigation sensors S ₀ and S ₂ Calculated from the movement amount of navigation sensors S ₀ and S ₃ Calculated from the movement amount of navigation sensors S ₁ and S ₂ Navigation sensor Calculated from the movement amount of S ₁ and S ₃ Calculated from the movement amount of the navigation sensors S ₂ and S ₃ The position calculation circuit 34 calculates the position with two combinations of all the navigation sensors S _{0 to} S ₃ that are not excluded. To do. The position stored in the storage unit 59 is stored in association with the combination of navigation sensors.

Next, the sensor position determination unit 52 determines two navigation sensors used to calculate the position of the nozzle (S110). For example, when the positions of the navigation sensors S _{0 to} S ₃ are calculated in 6 ways as described above, 6 positions are calculated for each navigation sensor. The navigation sensor S ₀ will be described as an example. First, the position of the navigation sensor _{S 0} is navigation sensors _{S 0} and _S 1, _{S 0} and _S 2, _{S 0} and _{S 3,} are calculated in the three combinations of.

Further, the positions of S ₁ and S ₂ are calculated from the movement amounts of the navigation sensors S ₁ and S ₂ that do not include the navigation sensor S ₀ in the combination. Here, since the relative position of the navigation sensors S ₁ or S ₂ and S ₀ are known, the position of the navigation sensor S ₁ and S ₂ of the navigation sensors are calculated from the movement amount S ₁ or S ₂ by the rotation angle θ The position of the navigation sensor S ₀ can be estimated. Similarly, the position of the navigation sensor S ₀ can be estimated from the position and the rotation angle of the navigation sensor S ₁ or S ₃ calculated from the movement amount of the navigation sensors S ₁ and S ₃ . The position of the navigation sensor S ₀ can be estimated from the position and the rotation angle of the navigation sensor S ₂ or S ₃ calculated from the movement amount of the navigation sensors S ₂ and S ₃ .

FIG. 16 shows the positions of the navigation sensors S ₂ and S _{3 and} the position of the navigation sensor S ₀ calculated from the rotation angle θ. When the distance between the navigation sensors S ₀ and S ₂ is Lw, the navigation sensors S ₀ and S ₂ are separated by Lw cos θ in the print medium coordinates. Therefore, when the coordinates of S ₂ are (X2, Y2), the coordinates (X0, Y0) of the navigation sensor S ₀ can be obtained as X0=X2-Lwcosθ, Y0=Y2+Lwsinθ.

In this way, the same six positions as the number of the above combinations are calculated or estimated for one navigation sensor S ₀ . Six position candidates are estimated for the navigation sensors S _{1 to} S ₃ .

However, it is not preferable to determine the position of the navigation sensor by simple averaging because there is a possibility that an abnormal value is included in the six positions. This is not excluded in step S109-2 because it has returned to normal in the current sampling cycle, but if it was abnormal in the previous sampling cycle, an abnormal value is mixed in this position because the previous position is abnormal. This is because there is a risk.

As shown in FIG. 13, the navigation sensors S _{0 to} S ₃ are arranged, and the movement amounts of the navigation sensors S ₂ and S ₃ were abnormal in the previous sampling cycle (for example, they protruded from the paper surface), but this sampling cycle. Then, let's say it was not abnormal. In this case, the sensor position determining unit 52 should determine the navigation sensors S ₀ and S ₁ to be the navigation sensors. The positions calculated by the navigation sensors S ₂ and S ₃ may be inaccurate because the previous time is abnormal. Since the position of the navigation sensors S ₀ and S navigation sensors S ₀ calculated by the combination of ₂ was also S ₂ abnormality is likely to be inaccurate. The position of S ₁ calculated by the combination of the navigation sensors S ₁ and S ₃ is also likely to be incorrect because S ₃ was abnormal. On the other hand, the positions of the navigation sensors S ₀ and S ₁ calculated by the combination of the navigation sensors S ₀ and S ₁ are highly likely to be accurate because they were calculated based on the movement amount that is not abnormal both last time and this time.

Similarly, the positions of the navigation sensors S ₂ and S ₃ estimated based on the relative positions to the positions of the navigation sensors S ₀ and S ₁ are also likely to be accurate.

Therefore, the sensor position determination unit 52 extracts a position with high reliability from the six positions, and statistically determines the two navigation sensors used for calculating or estimating this position. Specifically, the sensor position determination unit 52 determines a position with high reliability, for example, the median value or the average value excluding the maximum value and the minimum value.

(i) Positions (X, Y), which are the calculation results determined by the median value, are arranged in descending order of X and Y, and when the number of calculated positions is odd, the middle value is determined as the position of the navigation sensor. .. When the calculated number of positions is an even number, the average of two values near the middle is determined as the position of the navigation sensor.

For example, the navigation sensors _{S 0,} the position of the moving amount in three combinations of navigation sensors _{S 0} and _S 1, _{S 0} and _S 2, _{S 0} and _{S 3} are calculated. Further, based on the relative position of the navigation sensors _S 0 to S _3, the navigation sensors _{S 1} and _{S 0} are estimated from the position of _{S 2, S 0,} which is estimated from the position of the navigation sensor _{S 2} and _{S 3,} the navigation sensor There are three combinations of S ₀ that are estimated from the positions of S ₁ and S ₃ . If the X coordinate of S ₀ is six in the ascending order of X1, X2, X3, X4, X5, and X6, the average of X3 and X4 is selected. Since the position calculated from the normal movement amount has the same value or is similar, the position calculated from the normal movement amount can be selected by selecting the median value.

When this X3 is, for example, a combination of S ₀ and S ₁ , the sensor position determination unit 52 increments the count value by 1 for the navigation sensors S ₀ and S ₁ . In addition, when X4 is estimated from the positions of S ₁ and S ₂ , for example, the sensor position determination unit 52 increments the count value by 1 for S ₁ and S ₂ .

Similarly, with respect to the Y coordinate, if the Y coordinate of S ₀ is six in the ascending order of Y1, Y2, Y3, Y4, Y5, and Y6, Y3 and Y4 are selected. The average of Y3 and Y4 is selected.

When this Y3 is, for example, a combination of the navigation sensors S ₀ and S ₂ , the sensor position determination unit 52 increments the count value by 1 for the navigation sensors S ₀ and S ₂ . Further, when it is estimated from Y4, for example the position of the navigation sensor S ₂ and S _3, the sensor position determination unit 52 is increased by one count for navigation sensors S ₂ and S _3.

Therefore, the count values of S ₀ is 2, S ₁ is 2, S ₂ is 3, and S ₃ is 1. Thus, the count value of each navigation sensor in the set used to calculate the position of the navigation sensor with high reliability because it is in the center, and the estimation of the position of the navigation sensor with high reliability because it is in the center The count value of each navigation sensor in the set used is increased. Therefore, the count value is a value evaluated for reliability.

Similar processing is performed for S _{1 to} S ₃ . Thereby, for example, when the movement amounts of the navigation sensors S ₂ and S ₃ are abnormal in the previous sampling cycle, it is expected that the count values of the navigation sensors S ₀ and S ₁ will increase.

In this way, the count value is calculated for the navigation sensors S _{0 to} S ₃ . The sensor position determination unit 52 employs the top two navigation sensors in order of increasing count value as the navigation sensors used to calculate the position of the nozzle. The positions of the top two navigation sensors are calculated as median values, and the two navigation sensors are selected because the sensor position determination unit 52 calculates the rotation angle.

(ii) Determining the average value excluding the maximum and minimum values Separate X and Y obtained for each sensor, exclude the maximum and minimum values, and leave the remaining X and Y that have not been excluded. Calculate the average value of. Since the position calculated from the normal movement amount has the same value or is similar, the position calculated from the normal movement amount can be determined by excluding the maximum value and the minimum value and calculating the average value.

Similar to the case of the median value, it is assumed that the X coordinate of the navigation sensor S ₀ is X1, X2, X3, X4, X5, X6 in ascending order. X1 and X6 are deleted, and the average value of X2 to X5 is calculated. When this X2 is a combination of the navigation sensors S ₀ and S ₁ , the sensor position determination unit 52 increments the count value of the navigation sensors S ₀ and S ₁ by one. Further, X3 may due to a combination of navigation sensors _{S 0} and _{S 2,} to increase the count value one for a navigation sensor _{S 0} and _{S 2.} X4 is when it is estimated from the position of _{S 1} and _{S 2,} to increase by one count value for _{S 1} and _{S 2.} X5 is when it is estimated from the position of _{S 1} and _{S 3,} is increased by one count value for _{S 1} and _{S 3.}

Next, it is assumed that the Y coordinate of the navigation sensor S ₀ is six in the ascending order of Y1, Y2, Y3, Y4, Y5, and Y6. Y1 and Y6 are deleted, and the average value of Y2 to Y5 is calculated. When Y2 is a combination of the navigation sensors S ₀ and S ₁ , the sensor position determining unit 52 increments the count value of the navigation sensors S ₀ and S ₁ by one. Moreover, Y3 is a case with a combination of navigation sensors _{S 0} and _{S 2,} to increase the count value one for a navigation sensor _{S 0} and _{S 2.} Y4 is when it is estimated from the position of _{S 1} and _{S 2,} to increase by one count value for _{S 1} and _{S 2.} Y5 is when it is estimated from the position of _{S 1} and _{S 3,} is increased by one count value for _{S 1} and _{S 3.}

Therefore, the count value of the navigation sensor S ₀ is 4, the count value of S ₁ is 6, the count value of S ₂ is 4, and the count value of S ₃ is 2. Similar processing is performed for S _{1 to} S ₃ . Therefore, the count value is calculated for the navigation sensors S _{0 to} S ₃ . The sensor position determination unit 52 employs the top two navigation sensors in order of increasing count value as the navigation sensors used to calculate the position of the nozzle. The positions of the top two navigation sensors are calculated as average values, and the two navigation sensors are selected because the sensor position determination unit 52 calculates the rotation angle.

In this way, rather than simply calculating a plurality of positions for one navigation sensor and simply calculating the average value, a highly reliable navigation sensor can be selected based on the count value of the navigation sensor used for the median value or the average value. .. Therefore, there is a high possibility that a navigation sensor that does not extend from the four navigation sensors S _{0 to} S ₃ will be selected, and print formation can be continued without lowering print quality.

In addition, in (i), the number of navigation sensors not adopted as the median value may be counted. In addition, in (ii), the number of navigation sensors excluded because of the maximum and minimum values may be counted. In this case, the top two navigation sensors are selected in ascending order of count value.

In either case of (i) or (ii), n navigation sensors (2≦n<N) may be selected instead of the top two. For example, if there are six navigation sensors and two of them protrude from the print medium 12, the positions of the four navigation sensors are considered to be highly reliable. Therefore, even if the top four navigation sensors are selected and any two of them are selected, the print quality should not be significantly affected. That is, if the navigation sensors that may have protruded can be estimated by some method, the number of navigation sensors that are estimated not to protrude may be selected. However, it is considered that there is a high possibility that the two navigation sensors on the print medium 12 can be selected by selecting the top two, which is preferable.

As described above, the two navigation sensors are determined by the method (i) or (ii). The positions of the two navigation sensors are calculated as the median or the average, but the rotation angle is unknown. Since the rotation angle is required to calculate the position of the nozzle 61, the sensor position determination unit 52 notifies the position calculation circuit 34 of the two determined navigation sensors. Accordingly, the position calculation circuit 34 calculates the amount of change in the rotation angle (that is, the rotation angle) using the movement amounts of the two navigation sensors determined by the sensor position determination unit 52. Therefore, the position of the nozzle 61 can be calculated using the positions of the two navigation sensors (whichever one is sufficient) and the rotation angle.

The sensor position correction unit 53 corrects the positions of the navigation sensors (two) that have not been adopted, based on the relationship between the positions of the two adopted navigation sensors and the relative positions of the navigation sensors S _{0 to} S _3. You can That is, the positions of the navigation sensors (two) that are not adopted are replaced with the positions estimated by the relative position. Alternatively, the average value of the positions of the navigation sensors (2) not adopted and the positions estimated by the relative positions is set as the positions of the navigation sensors (2) not adopted.

Further, the necessity of correction may be determined. In this case, it is determined whether or not an abnormal value is mixed at 6 positions of one navigation sensor. The sensor position correction unit 53 obtains, for example, the standard deviation of the position of one navigation sensor, and when the standard deviation is equal to or larger than the threshold value, determines that an abnormal value is mixed. Then, the position is corrected only when the abnormal values are not mixed. Variance may be used instead of standard deviation.

Next, the position calculation circuit 34 calculates the current position of each nozzle 61 using the current position of the navigation sensor determined in step S110 (S111).

Next, the CPU 33 causes the image reading unit 38 to read the image. The image reading unit 38 reads the image data of the peripheral image of each nozzle 61 from the DRAM 29 based on the calculated position of each nozzle 61 (S112).

Next, the IJ recording head control unit 44 compares the position coordinates of each image element forming the peripheral image with the position coordinates of each nozzle 61 (S113). The position calculation circuit 34 calculates the acceleration of the nozzle 61 using the past position and the current position of the nozzle 61. As a result, the position calculation circuit 34 calculates the position of the nozzle 61 for each ink ejection cycle of the IJ recording head 24 that is shorter than the cycle in which the navigation sensor I/F 42 acquires the movement amount. The IJ recording head control unit 44 determines whether the position coordinates of the image element are included in a predetermined range from the position of the nozzle 61 calculated by the position calculation circuit 34 (ejection nozzle availability determination).

If the ejection conditions are not satisfied, the process returns to step S108. If the ejection condition is satisfied, the IJ print head controller 44 outputs the data of the image element for each nozzle 61 to the IJ print head drive circuit 23 (S115). As a result, ink is ejected onto the print medium 12.

Next, the CPU 33 determines whether all the image data has been output (S116). If not output, the processes from steps S108 to S115 are repeated.

When all the image data has been output, the CPU 33 lights up the LED of the OPU 26, for example, and notifies the user that the printing is completed (S117).

If the user determines that the output is sufficient without outputting all the image data, the user may press the print completion button, the OPU 26 accepts it, and the printing may be terminated. The user may turn off the power after printing is completed, or the power may be automatically turned off when printing is completed.

As described above, since there are three or more navigation sensors, the HMP can continue the calculation of the position of the nozzle 61 by using two or more navigation sensors, suppress printing quality deterioration, and continue printing.

<Other application examples>
The best mode for carrying out the present invention has been described above with reference to the embodiments, but the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. And substitutions can be added.

For example, the constituent elements of the SoC 50 and the ASIC/FPGA 40 described above may be included in either one depending on the CPU performance, the circuit scale of the ASIC/FPGA 40, and the like.

Further, although it has been described in the present embodiment that the image is formed by ejecting ink, the image may be formed by irradiating visible light, ultraviolet rays, infrared rays, laser, or the like. In this case, as the print medium 12, for example, one that responds to heat or light is used. Alternatively, a transparent liquid may be ejected. In this case, visible information is obtained when light of a specific wavelength range is irradiated. Alternatively, a metal paste or resin may be discharged.

The navigation sensor 30 is an example of the movement amount detecting unit, the position calculating circuit 34 is an example of the second position calculating unit, the image reading unit 38 is an example of the first position calculating unit,
The sensor position determination unit 52 is an example of a selection unit, the abnormality detection unit 51 is an example of an exclusion unit, and the sensor position correction unit 53 is an example of a correction unit. The position of the navigation sensor 30 is an example of the detecting means position. The IJ recording head control unit 44 and the like are an example of a droplet discharge device, and the HMP 20 is an example of a droplet discharge device.

11 image data output device 12 print medium 30 navigation sensor 33 CPU
34 position calculation circuit 51 abnormality detection unit 52 sensor position determination unit 53 sensor position correction unit 61 nozzle

Japanese Patent Publication No. 2010-522650

Claims (9)

A position detecting device for detecting a position on a moving surface of a mounted object equipped with the position detecting device,
N (N>2) movement amount detecting means for detecting the movement amount on the moving surface,
First position calculation means for calculating the position using the movement amounts detected by the n (2≦n<N) movement amount detection means selected based on the output of the movement amount detection means,
Second position calculation means for calculating a plurality of detection means positions of the movement amount detection means for one movement amount detection means using the movement amount detected by the movement amount detection means,
Selection means for selecting the n movement amount detection means based on a result of comparing the plurality of detection means positions of one movement amount detection means,
The position detecting device, wherein the first position calculating means calculates the position by using the movement amount detected by any two movement amount detecting means selected from the n pieces selected by the selecting means . The movement amount detection means outputs reliability information of the movement amount,
The exclusion unit that excludes the movement amount of the movement amount detection unit that has detected the movement amount whose reliability information is less than a threshold value from the target whose position is calculated by the first position calculation unit. The position detection device described. The second position calculation means calculates one detection means position by using the movement amounts detected by the two movement amount detection means, and one detection means position is different from the two movements. Calculated for each combination of quantity detection means,
The selection means sets the detection means position of the movement amount detection means from the detection means positions of other movement amount detection means based on the calculated detection means position and the relative positions of the N movement amount detection means. Estimate,
The median value of the plurality of detection means positions of the one movement amount detection means is determined as the detection means position of the movement amount detection means,
The first position calculating means, wherein for calculating the position using the movement amount of any two of said moving amount detecting means of the n selected with the detection means the position where the selecting means has determined that the detected The position detection device according to item 1 . The selection means increases the count value of the set of movement amount detection means used for calculation or estimation of the detection means position determined to the median value,
The position detecting device according to claim 3 , wherein the upper n movement amount detecting means are selected in descending order of the count value. The second position calculation means calculates one detection means position by using the movement amounts detected by the two movement amount detection means, and one detection means position is different from the two movements. Calculated for each combination of quantity detection means,
The selection means sets the detection means position of the movement amount detection means from the detection means positions of other movement amount detection means based on the calculated detection means position and the relative positions of the N movement amount detection means. Estimate,
The maximum value and the minimum value of the plurality of detection means positions of the one movement amount detection means are excluded, and the average value of the remaining detection means positions is determined as the detection means position of the movement amount detection means,
The first position calculating means, wherein for calculating the position using the movement amount of any two of said moving amount detecting means of the n selected with the detection means the position where the selecting means has determined that the detected The position detection device according to item 1 . The selection means increases the count value of the set of movement amount detection means used for calculation or estimation of the detection means position used for calculation of the average value,
The position detecting device according to claim 5 , wherein the upper n movement amount detecting means are selected in descending order of the count value. Based on the relative position of at least one of the n moving amount detecting units selected by the selecting unit and the relative position of the N moving amount detecting units, the moving amount detection not selected by the selecting unit is performed. The position detection device according to claim 1 , further comprising a correction unit that corrects the position of the unit. Said correction means, if it contains an abnormal value in a plurality of detecting means position calculated for one of said moving amount detecting means, claim does not correct the position of the displacement detection means for said selecting means does not select 7 The position detection device according to. A position detecting device according to any one of claims 1 to 8 ;
Droplet discharge means for discharging droplets for forming an image at the position of the mounted object,
A droplet discharge device having a.

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