JP7120348B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus .

2. Description of the Related Art A printer is known that forms an image by ejecting ink or the like when a sheet of paper is conveyed and reaches an image forming position. On the other hand, due to the miniaturization of notebook PCs and the spread of smart devices, there is an increasing need for miniaturization and portability of printers. Therefore, printers (hereinafter referred to as HMPs: handy mobile printers) that are miniaturized by removing the paper transport system from printers are being put to practical use. Since the HMP is not equipped with a paper transport system, a person moves the paper surface to scan the paper surface and eject ink.

The HMP detects its own position on the paper surface and ejects ink for forming an image according 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 (see, for example, Patent Document 1). A navigation sensor is a sensor that optically detects minute edges of a paper surface to detect the amount of movement for each cycle time. With two navigation sensors, the HMP can detect the rotation angle in the direction horizontal to the plane of the paper.

However, the conventional HMP has a problem that it is difficult to reduce the size of the bottom surface. First, it is possible to detect the position even if there is only one navigation sensor. The reason why two are necessary is to calculate the rotation angle of the HMP with respect to the paper surface and to calculate the position based on the rotation angle. Further, it is preferable that the distance between the two navigation sensors is long to some extent in order to improve the detection accuracy of the rotation angle. For these reasons, it has been difficult to reduce the size of the bottom portion of the conventional HMP.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a position detection device capable of reducing the size of the bottom portion.

The present invention relates to an image forming apparatus that is moved on a medium and forms an image in accordance with the movement on the medium, comprising movement amount detection means for detecting the amount of movement of the image forming apparatus in movement on the medium. an attitude detection means for detecting an amount of change in the attitude of the image forming apparatus according to movement on the medium; and an image forming means for forming an image on the medium , wherein the amount of movement and the change in the attitude are provided. calculating the position of the image forming means on the medium based on the amount, forming an image if there is an image element corresponding to the calculated position, and forming the image on the position where the image has already been formed ; , and the movement amount detection means and the attitude detection means are implemented by sensors different from each other, and in the calculation of the position, the movement amount on the medium output by the movement amount detection means is It is characterized in that the acquired amount of change in posture is used for conversion into coordinates on the medium.

It is possible to provide an image forming apparatus capable of reducing the size of the bottom portion.

It is an example of the figure which shows the outline of a structure of HMP of this embodiment. It is an example of the figure which shows image formation by HMP typically. It is an example of the hardware block diagram of HMP. It is an example of the figure explaining the structure of a control part. It is an example of the figure explaining the principle by which a gyro sensor detects an angular velocity. 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 moving amount|distance by a navigation sensor. 1 is an example of a configuration diagram of an IJ recording head driving circuit; FIG. It is an example of the top view of HMP. It is an example of the figure explaining the calculation method of the coordinate system of HMP, and a position. FIG. 10 is an example of a diagram illustrating how to obtain the rotation angle dθ of the HMP that occurs during image formation; It is an example of the figure explaining the relationship between a target ejection position and the position of a nozzle. It is an example of the flowchart figure explaining the operation|movement procedure of an image data output device and HMP. FIG. 10 is an example of a diagram illustrating an image formable range when two navigation sensors are shown for comparison; FIG. 10 is an example of a diagram illustrating an image formable range when there is one navigation sensor; It is an example of the figure explaining the example of arrangement|positioning of a navigation sensor. It is an example of a diagram showing an example of the arrangement of gyro sensors. It is an example of the figure explaining the attitude|position of HMP which a gyro sensor detects. FIG. 10 is an example of a diagram showing changes in the resolution of the distance between sensor papers and the amount of movement; It is an example of the figure explaining the attachment position of a navigation sensor. FIG. 10 is an example of a diagram illustrating the floating amount of the navigation sensor from the printing medium; FIG. 10 is an example of a flowchart for explaining an operation procedure of an image data output device and an HMP (Embodiment 2);

EMBODIMENT OF THE INVENTION Hereinafter, it demonstrates, referring drawings for the form for implementing this invention.

First, general features of the handy mobile printer (hereinafter referred to as HMP) of the present embodiment will be described with reference to FIG. FIG. 1 is a diagram showing the outline of the configuration of the HMP 20 of this embodiment. FIG. 1(a) shows a block diagram of a conventional HMP 20 shown for comparison. A conventional HMP 20 has one IJ recording head 24 and two navigation sensors 30 (hereinafter referred to as navigation sensors S ₀ and S ₁ for distinction).

FIG. 1(b) shows an image formable range 501 of the conventional HMP 20. FIG. The HMP 20 of FIG. 1A has an IJ recording head 24 on the left side and two navigation sensors S ₀ and S ₁ arranged vertically on the right side. The distance between the navigation sensor S1 and the lower end of the nozzle 61 is _A [mm], and the distance from the nozzle 61 to the navigation sensors _S0 and S1 is B [ _mm ]. Since the navigation sensors S ₀ and S ₁ protrude from the print medium 12 , the HMP 20 cannot move more than B [mm] to the right from the left edge of the print medium 12 . Further, since the distance between the navigation sensor S1 and the lower end of the nozzle 61 is _A [mm], the HMP 20 cannot move below the lower end of the print medium 12 by A [mm]. Therefore, as shown in the figure, there are places where printing is not possible under and on the sides of the print medium 12 .

FIG.1(c) shows the block diagram of HMP20 of this embodiment. The HMP 20 of this embodiment has one IJ recording head 24 , one navigation sensor S ₀ , and one gyro sensor 31 . FIG. 1D shows an image formable range 501 of the HMP 20 of this embodiment. Let A [mm] be the distance between the lower end of the nozzle 61 and the navigation sensor _S0 . The HMP 20 cannot move below A [mm] from the bottom edge of the print medium 12 because the navigation sensor _S0 protrudes from the print medium 12 . On the other hand, the horizontal spacing between nozzle 61 and navigation sensor S0 is _zero , allowing HMP 20 to move from the left edge of print medium 12 to the right edge. Therefore, as shown in the figure, there are places where printing is not possible only on the lower side.

As is clear from comparing FIG. 1(b) and FIG. 1(d), the number of navigation sensors can be reduced to one by mounting the gyro sensor 31, and the size of the bottom surface can be reduced. As a result, the image formable range 501 can be enlarged.

<Terms>
The size of the bottom surface is the size of the area surrounding the navigation sensor and the nozzle 61, or the size of the bottom surface of the HMP 20 that cannot be made smaller due to the limitations of this area. The actual size of the bottom surface of the HMP 20 may be larger than the area surrounding the navigation sensor and the nozzle 61, and may be determined in consideration of operability, design, and the like.

A mounted object is an object on which a position detection device is mounted. It may be an object whose position can be detected on a moving plane. For example, the HMP 20 is an example of the mounted object. In addition, since the position detection device can detect the moved distance, the distance measuring device can also be an example of the mounted object.

The moving surface may be any surface on which the HMP 20 can move, and includes curved surfaces as well as flat surfaces. A specific example is the print medium 12, but the present invention is not limited to this.

Also, the posture of an object refers to degrees of freedom representing rotation angles (rotation angles about three axes passing through the center of gravity of the rigid body and orthogonal to each other) among the six degrees of freedom of the rigid body. Of these, the posture of an object on a plane is represented by a rotation angle about an axis perpendicular to the plane.

Calculating a position means obtaining information about the position by performing an operation 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 can be obtained, and in this embodiment, there is no strict distinction between the calculation of the position and the detection of the position.

<Image formation by HMP20>
FIG. 2 is an example of a diagram schematically showing image formation by the HMP 20. As shown in FIG. Image data is transmitted to the HMP 20 from an image data output device 11 such as a smartphone or a PC (Personal Computer). The user grips the HMP 20 and scans the print medium 12 (for example, standard paper, notebook, etc.) freehand without floating.

The HMP 20 detects its position with the navigation sensor _S0 and the gyro sensor 31 as will be 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 locations where ink has already been ejected are masked (because they are not subject to ink ejection), the user can form an image by scanning the HMP 20 in any direction on the print medium 12 .

The reason why it is preferable that the HMP 20 does not rise above the print medium 12 is that the navigation sensor _S0 uses reflected light from the print medium 12 to detect the amount of movement. When the HMP 20 floats up from the print medium 12, reflected light cannot be detected, and the amount of movement cannot be detected. Even if the navigation sensor _S0 protrudes from the print medium 12, the reflected light may not be detected due to the thickness of the print medium 12, or the position may be shifted even if it can be detected. For this reason, the navigation sensor _S0 is preferably scanned over the print medium 12, and preferably the nozzle 61 and the navigation sensor _S0 are both present above the print medium 12 as described above.

<Configuration example>
FIG. 3 shows an example of a hardware configuration diagram of the HMP 20. As shown in FIG. The HMP 20 is an example of a droplet ejection device or image forming device that forms an image on the print medium 12 . The entire operation of the HMP 20 is controlled by a control unit 25, to which a communication I/F 27, an IJ recording head drive circuit 23, an OPU 26, a ROM 28, a DRAM 29, a navigation sensor 30, and a gyro sensor 31 are electrically connected. It is Further, since the HMP 20 is driven by electric power, it has a power supply 22 and a power supply circuit 21 . 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, the navigation sensor 30, and the like through the wiring indicated by the dotted line 22a. It is supplied to the gyro sensor 31 .

A battery is mainly used as the power source 22 . A solar battery, 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 part of the HMP 20 . Also, the voltage of the power supply 22 is stepped down or stepped up to a voltage suitable for each part. When the power supply 22 is a rechargeable battery, the power supply circuit 21 detects the connection of the AC power supply and connects to the battery charging circuit to enable the power supply 22 to be charged.

The communication I/F 27 receives image data from an 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 communication standards such as wireless LAN, Bluetooth (registered trademark), NFC (Near Field Communication), infrared rays, 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 also be used.

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

The DRAM 29 is used to store image data received by the communication I/F 27 and store firmware developed 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 for each predetermined cycle time. The navigation sensor 30 has, for example, a light source such as a light emitting diode (LED) or a laser, and an imaging 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 (imaged) one after another and the distance between the edges is analyzed to obtain the amount of movement. In this embodiment, only one navigation sensor 30 is mounted on the bottom surface of the HMP 20 . Conventionally, there were two. However, for explanation purposes, the HMP 20 having two navigation sensors 30 may be explained. A multi-axis acceleration sensor may be used as the navigation sensor 30, and the HMP 20 may detect the amount of movement of the HMP 20 only with the acceleration sensor.

The gyro sensor 31 is a sensor that detects the angular velocity when the HMP 20 rotates around an axis perpendicular to the print medium 12 . Details will be described later.

An 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, it is not limited to this, and may have a liquid crystal display and may further have a touch panel. Also, it may have a voice input function.

The IJ printhead drive circuit 23 uses the drive waveform data to generate a drive waveform (voltage) for driving the IJ printhead 24 . A driving waveform can be generated according to the size of ink droplets.

The IJ recording head 24 is a head for ejecting ink. In the drawing, four colors of CMYK ink can be ejected, but a single color may be used, and five or more colors may be ejected. A plurality of nozzles 61 (ejection portions) for ejecting ink are arranged in a row (or two or more rows) for each color. Further, the ink ejection method may be a piezo method, a thermal method, or other methods. The IJ recording head 24 is a functional component that discharges/sprays liquid from the nozzles 61 . The liquid to be ejected is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the IJ recording head 24, but the viscosity is 30 [mPa·s] at room temperature and pressure, or by heating or cooling. It is preferable to be as follows. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional-imparting materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium. , edible materials such as natural pigments, solutions, suspensions, emulsions, etc. These are, for example, inkjet inks, surface treatment liquids, components of electronic elements and light emitting elements, and formation of electronic circuit resist patterns It can be used for applications such as liquids for liquids and material liquids for three-dimensional modeling.

The control unit 25 has a CPU 33 and controls the entire HMP 20 . Based on the movement amount detected by the navigation sensor 30 and the angular velocity detected by the gyro sensor 31, the control unit 25 determines the position of each nozzle of the IJ recording head 24 and the image to be formed according to the position. Judgment on whether ejection nozzles are possible or not is performed. Details of the control unit 25 will be described below.

FIG. 4 is an example of a diagram for explaining the configuration of the control unit 25. As shown in FIG. The control unit 25 has SoC 50 and ASIC/FPGA 40 . SoC 50 and ASIC/FPGA 40 communicate via buses 46 and 47 . This means that the ASIC/FPGA 40 may be designed with either implementation technology, and may be configured with implementation technologies other than the ASIC/FPGA 40 . Also, the SoC 50 and the ASIC/FPGA 40 may be configured as one chip or substrate without using separate 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, a ROM CTL (controller) 36, and the like, which are connected via a bus 47. FIG. Note that the components of the SoC 50 are not limited to these.

The ASIC/FPGA 40 also includes an Image RAM 37, a DMAC 38, a rotator 39, an interrupt controller 41, a navigation sensor I/F 42, a print/sensor timing generator 43, an IJ recording head controller 44 and a gyro, which are connected via a bus 46. It has sensor I/F45. Note that the components of the ASIC/FPGA 40 are not limited to these.

The CPU 33 executes firmware (programs) 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. FIG. In addition, the operations of Image RAM 37, DMAC 38, rotator 39, interrupt controller 41, navigation sensor I/F 42, print/sensor timing generation unit 43, IJ recording head control unit 44, gyro sensor I/F 45, etc. in ASIC/FPGA 40 Control.

The position calculation circuit 34 calculates the position (coordinate information) of the HMP 20 based on the amount of movement in each sampling period detected by the navigation sensor 30 and the angular velocity in each sampling period detected by the gyro sensor 31 . The position of the HMP 20 is strictly the position of the nozzle 61, but the position of the nozzle 61 can be calculated if the position of the navigation sensor 30 is known. In this embodiment, unless otherwise specified, the position of the navigation sensor 30 refers to the position of the navigation sensor _S0 . Also, the position calculation circuit 34 calculates the target ejection position. Note that 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 will be described later. Further, the position calculation circuit 34 estimates the moving direction and acceleration based on the difference between the past position and the latest position, and predicts the position of the navigation sensor 30 at the next ejection timing, for example. In this way, ink can be ejected while suppressing a delay in scanning by the user.

The memory CTL 35 is an interface with the DRAM 29 , requests data from the DRAM 29 , sends acquired firmware to the CPU 33 , and sends acquired image data to the ASIC/FPGA 40 .

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

The rotator 39 rotates the image data acquired by the DMAC 38 according to the head that ejects ink, the position of the nozzles in the head, and the tilt of the head caused by an installation error or the like. The DMAC 38 outputs the rotated image data to the IJ recording head controller 44 .

Image RAM 37 temporarily stores the image data acquired by DMAC 38 . That is, a certain amount of image data is buffered and read according to the position of the HMP 20 .

The IJ recording head control unit 44 converts the image data (bitmap data) into a set of points representing an image in terms of size and density by applying dithering or the like to the image data (bitmap data). As a result, the image data becomes data of the ejection position and the dot size. The IJ printhead control unit 44 outputs a control signal corresponding to the dot size to the IJ printhead drive circuit 23 . The IJ recording head driving circuit 23 generates a driving waveform (voltage) using the driving waveform data corresponding to the control signal as described above.

The navigation sensor I/F 42 communicates with the navigation sensor 30, receives movement amounts ΔX′ and ΔY′ (these will be described later) as information from the navigation sensor 30, and stores the values in an internal register.

The print/sensor timing generator 43 notifies the navigation sensor I/F 42 and the gyro sensor I/F 45 of the timing for reading information, and notifies the IJ recording head controller 44 of the driving timing. The cycle of timing for reading information is longer than the cycle of ink ejection timing. The IJ recording head control unit 44 determines whether or not ink is to be ejected, and determines that ink is ejected if there is a target ejection position to which ink should be ejected, and that ink is not ejected if there is no target ejection position.

The gyro sensor I/F 45 acquires the angular velocity detected by the gyro sensor 31 at the timing generated by the print/sensor timing generator 43 and stores the value in a register.

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 to notify the SoC 50 of this. By this interrupt, the CPU 33 acquires ΔX′ and ΔY′ stored in the internal register by the navigation sensor I/F 42 . In addition, it also has a status notification function such as an error. Similarly, regarding the gyro sensor I/F 45, the interrupt controller 41 outputs an interrupt signal to the SoC 50 to notify that communication with the gyro sensor 31 has ended.

<Gyro sensor>
FIG. 5 is an example of a diagram for explaining the principle by which the gyro sensor 31 detects angular velocity. When a moving object is rotated, a Coriolis force is generated in a direction perpendicular to both the direction of movement of the object and the axis of rotation.

In order to move the object, the gyro sensor 31 generates a velocity v (vector) by vibrating a MEMS (Micro Electro Mechanical Systems) element. When a rotating MEMS element having a mass m that is vibrating is externally rotated with an angular velocity ω (vector), a Coriolis force is applied to the MEMS element. The Coriolis force F can be expressed as follows.
F=-2mΩ×v
Note that "x" represents the outer product of vectors, and the direction of the Coriolis force F is the direction orthogonal to the moving direction of the object and the rotation axis as described above. The MEMS element has, for example, comb-shaped electrodes, and the gyro sensor 31 detects displacement caused by the Coriolis force F as a change in capacitance. A signal of the Coriolis force F is amplified and filtered in the gyro sensor 31, then calculated into an angular velocity and output. That is, since F, m, and v are known, the angular velocity ω can be extracted.

<About the navigation sensor>
FIG. 6 is a diagram showing a configuration example of the hardware configuration of the navigation sensor. Navigation sensor 30 has host I/F 301 , image processor 302 , LED driver 303 , two lenses 304 and 306 and image array 305 . The LED driver 303 integrates an LED and a control circuit, and emits LED light according to a command from the image processor 302 . Image array 305 receives the reflected light of the LED light from print medium 12 via lens 304 . Two lenses 304 and 306 are placed in optical focus with respect to the surface of print medium 12 .

The image array 305 has photodiodes or the like that are sensitive to the wavelength of the 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' above) of the navigation sensor from the image data. Image processor 302 outputs the calculated moving distance to control unit 25 via host I/F 301 .

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

Next, operation of the navigation sensor 30 will be described with reference to FIG. FIG. 7 is a diagram for explaining how the navigation sensor 30 detects the amount of movement. The light emitted by the LED driver 303 is applied to the surface of the print medium 12 through the lens 306 . The surface of the print medium 12 has minute irregularities of various shapes, as shown in FIG. 7(a). For this reason, shadows of various shapes are generated.

The image processor 302 receives reflected light via the lens 304 and the image array 305 at each predetermined sampling timing, and acquires image data 310 . The image processor 302 matrixes the image data 310 generated as shown in FIG. 7(b) 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, detects the number of rectangular regions in which the image data 310 has moved, It is calculated as the moving distance. Assume that the HMP 20 moves in the ΔX direction shown in FIG. 7(b). Comparing the image data 310 at t=0 and t=1, the shape on the right end matches the shape in the center. Therefore, since the shape has moved in the -X direction, it can be seen that the HMP 20 has moved by one mass in the X direction. The same is true for 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. As shown in FIG. First, the IJ recording head 24 has a plurality of nozzles 61 and each nozzle 61 is provided with an actuator. The actuator may be of either thermal type or piezo type. The thermal method applies heat to the ink in the nozzle to expand it, and the ink droplet is ejected from the nozzle 61 by this expansion. In the piezo system, a piezoelectric element pushes a nozzle wall to push out the ink inside, thereby ejecting an ink droplet.

The IJ recording head drive circuit 23 comprises 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 image data SD, which is serial data for the number of nozzles 61 (the same number of actuators) of the IJ print head 24, to the IJ print head drive circuit 23 using the image data transfer clock SCK. Transfer to shift register 235 .

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

After latching the image data SD, the IJ recording head control unit 44 outputs to the analog switch 231 a head driving waveform Vcom for ejecting ink droplets of each gradation value from each nozzle. At this time, the IJ recording head control unit 44 supplies the head drive mask pattern MN as a gradation control signal to the gradation decoder 233. The head drive mask pattern MN is selected in accordance with the timing of the drive waveform. 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 print head has a different waveform 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 .

The configuration of FIG. 8 and its description are those generally employed in inkjet printers. As long as it can eject ink droplets, it may be installed in the HMP 20 without being limited to the configuration shown in FIG.

<Nozzle Position in IJ Print Head>
Next, nozzle positions 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. FIG. 9B is an example of a diagram illustrating only the IJ recording head 24. FIG. The illustrated surface is the surface facing the print medium 12 .

The HMP 20 of this embodiment has one navigation sensor _S0 . S1 in FIG. 9(a) indicates the installation position when there are _two navigation sensors for convenience of explanation. The length between the two navigation sensors S ₀ and S ₁ is the distance L when there are two navigation sensors 30 . The longer the distance L, the better. This is because the longer the distance L, the smaller the detectable minimum rotation angle θ, and the smaller the positional error of the HMP 20 .

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 or zero (in contact with the IJ recording head 24). Also, if there is only one navigation sensor 30 , the navigation sensor S ₀ is placed anywhere around the IJ recording head 24 . Accordingly, the illustrated position of navigation sensor _S0 is an example. However, since the distance between the _IJ recording head 24 and the navigation sensor S0 is short, the size of the bottom surface of the HMP 20 can be easily reduced.

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

If the position calculation circuit 34 or the like calculates the position of the navigation sensor _S0 , 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 illustrating a coordinate system of the HMP 20 and a method of calculating the position. In this embodiment, the horizontal direction to the print medium 12 is set to the X axis, and the vertical direction to the printing medium 12 is set to the Y axis. The origin is the position of navigation sensor _S0 when imaging begins. These coordinates will be referred to as print media coordinates. On the other hand, the navigation sensor S0 outputs the amount of movement on the coordinate axes ( _X' -axis, Y'-axis) in FIG. 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, the case where the HMP 20 rotates θ clockwise with respect to the print medium 12 will be described as an example. It is believed that it would be difficult for the user to scan the HMP 20 without tilting it at all relative to the print media coordinates, resulting in a non-zero θ. If not rotated at all, then X=X' and Y=Y'. However, when the HMP 20 is rotated by a rotation angle θ with respect to the print medium 12, the output of the navigation sensor _S0 and the actual position of the HMP 20 on the print medium 12 do not match. The clockwise direction of the rotation angle θ is positive, the right direction of X and X′ is positive, and the upward direction of Y and Y′ is positive.

FIG. 10A is an example of a diagram explaining the X coordinate of the HMP 20. FIG. FIG. 10(a) shows the correspondence between movement amounts ΔX′ and ΔY′ detected by the navigation sensor _S0 and X and Y when the HMP 20 with the rotation angle θ moves only in the X direction with the same rotation angle θ. . Note that when there are two navigation sensors 30, since the relative positions are fixed, the outputs (movement amounts) of the two navigation sensors 30 are the same. The X coordinate of the navigation sensor _S0 is X1+X2, and X1+X2 is determined from .DELTA.X', .DELTA.Y' and the rotation angle .theta.

FIG. 10(b) shows the correspondence between the movement amounts ΔX′ and ΔY′ detected by the navigation sensor _S0 and X and Y when the HMP 20 with the rotation angle θ moves only in the Y direction with the same rotation angle θ. . The Y coordinate of the navigation sensor _S0 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 and Y directions with the rotation angle .theta., .DELTA.X' and .DELTA.Y' output from the navigation sensor _S0 can be converted into X and Y coordinates of the print medium as follows.
X = ΔX'cos θ + ΔY'sin θ (1)
Y=-ΔX'sinθ+ΔY'cosθ (2)
<<Detection of rotation angle θ>>
In this embodiment, the position calculation circuit 34 obtains the rotation angle θ from the output of the gyro sensor 31 . However, in order to show that the longer the distance L, the position can be obtained with higher accuracy, the method of obtaining the rotation angle θ when there are two navigation sensors 30 will be described.

FIG. 11 is an example of a diagram illustrating how to obtain the rotation angle dθ of the HMP 20 that occurs during image formation. The rotation angle dθ is calculated using the movement amount ΔX′ detected by the two navigation sensors S ₀ and S ₁ . Let _ΔX'0 be the amount of movement detected by the navigation sensor S0 on the upper side of the printing medium 12, and _ΔX'1 be the amount of movement detected by the navigation sensor S1. In FIG. 11, the already obtained rotation angle is θ.

When the HMP 20 rotates by dθ while moving in parallel, the amounts of movement ΔX'0 and ΔX'1 do not match. However, since both outputs are the amount of movement in the direction perpendicular to the straight line connecting the two navigation sensors S ₀ and S ₁ , the difference between the amounts of movement ΔX'0 and ΔX'1 is calculated as "ΔX'0 - ΔX'1". be able to. This difference is a value caused by the dθ rotation of the HMP 20 . Also, 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 position calculation circuit 34 can obtain the rotation angle θ by integrating the dθ. As shown in equations (1) and (2), the rotation angle θ is used to calculate the position, so the rotation angle θ affects the accuracy of the position. Also, as can be seen from the equation (3), it is preferable to increase the distance L in order to detect a smaller dθ. Therefore, although the distance L affects the accuracy of the position, the larger the distance L, the larger the base area of the HMP 20 and the smaller the image formable range 501 .

Next, a method of calculating the rotation angle θ using the output of the gyro sensor 31 will be described. The output of the gyro sensor 31 is the angular velocity ω.
ω=dθ/dt
Therefore, if dt is the sampling period, the rotation angle dθ can be expressed as follows.
dθ=ω×dt
Therefore, the current rotation angle θ (time t=0 to N) is as follows.

このように、ジャイロセンサ３１でも回転角θを求めることができる。式（１）（２）に示すように、回転角θを用いて位置を算出できる。ナビゲーションセンサＳ_０の位置を算出できれば、図９（ｂ）に示したａ～ｅの値により、位置算出回路３４は各ノズル６１の座標を算出することができる。なお、式（１）のＸ、式（２）のＹはそれぞれサンプリング周期における変化量なのでこのＸ，Ｙを累積することで現在の位置が求められる。

Thus, the gyro sensor 31 can also obtain the rotation angle θ. As shown in equations (1) and (2), the position can be calculated using the rotation angle θ. If the position of the navigation sensor _S0 can be calculated, the position calculation circuit 34 can calculate the coordinates of each nozzle 61 from the values a to e shown in FIG. 9(b). Since X in Equation (1) and Y in Equation (2) are the amount of change in each sampling period, the current position can be obtained by accumulating X and Y.

<Target discharge position>
Next, the target ejection position will be described with reference to FIG. 12 . FIG. 12 is an example of a diagram illustrating the relationship between the target ejection position and the position of the nozzle 61. As shown in FIG. The target ejection positions G1 to G9 are target positions (pixel formation destinations) where the HMP 20 makes ink land from the nozzles 61 . The target ejection positions G1 to G9 can be obtained from the initial position of the HMP 20 and the resolution (Xdpi, Ydpi) of the HMP 20 in the X-axis/Y-axis directions.

For example, when the resolution is 300 dpi, target ejection positions are set at intervals of about 0.084 [mm] in the longitudinal direction of the IJ print head 24 and in the direction perpendicular thereto. If there are pixels to be ejected at these target ejection positions G1 to G9, the HMP 20 ejects ink.

However, in practice, it is difficult to capture the timing at which the nozzles 61 and the target ejection positions completely match, so the HMP 20 provides an allowable error 62 between the target ejection position and the current position of the nozzles 61 . Then, when the current position of the nozzle 61 is within the range of the allowable error 62 from the target ejection position, the ink is ejected from the nozzle 61 (providing such an allowable range is called "ejection nozzle propriety determination").

Also, as indicated by an arrow 63, the HMP 20 monitors the moving direction and acceleration of the nozzle 61, and predicts the position of the nozzle 61 at the next ejection timing. Therefore, it is possible to prepare for ink ejection by comparing the predicted position with the tolerance 62 .

<Operation procedure>
FIG. 13 is an example of a flowchart for explaining the operation procedure of the image data output device 11 and the HMP 20. As shown in FIG. 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 powered by a battery or the like to start up.

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

The user performs an operation to print the selected image on the HMP 20 (U103). The HMP 20 accepts a print job execution request. Image data is sent to the HMP 20 by a print job request.

The user holds the HMP 20 and determines its initial position on the print medium 12 (eg notebook) (U104).

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

The user freely scans the HMP 20 by sliding it over the print medium 12 (U106).

Next, the operation of the HMP 20 will be explained. The following operations are performed by the CPU 33 executing the firmware.

The HMP 20 is also started when the power is turned on. The CPU 33 of the HMP 20 initializes the hardware elements of FIGS. 3 and 4 incorporated in the HMP 20 (S101). For example, it initializes the registers of the navigation sensor I/F 42 and the gyro sensor I/F 45 and sets the timing value in the print/sensor timing generator 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 the initialization is completed, and repeats this determination if not completed (S102).

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

In response to a print job execution request, the communication I/F 27 of the HMP 20 receives input of image data from the image data output device 11, and notifies the user that the image has been 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 (movement amount) (S105). As a result, the navigation sensor I/F 42 communicates with the navigation sensor _S0 , acquires the movement amount detected by the navigation sensor _S0 , and stores it in a register or the like (S1001). The CPU 33 reads the movement amount from the navigation sensor I/F 42 .

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

Further, when the initial position is acquired, the print/sensor timing generation unit 43 starts generation of timing (S107). The print/sensor timing generator 43 instructs the timing to the navigation sensor I/F 42 and the timing to the gyro sensor I/F 45 when the timing for acquiring the amount of movement of the navigation sensor _S0 set in the initialization is reached. This is performed periodically 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 angular velocity information (S108). This determination is made based on a notification from the interrupt controller 41 , but may be determined by the CPU 33 counting the same timing as the print/sensor timing generator 43 .

When it is time to acquire the movement amount and the angular velocity information, the CPU 33 of the HMP 20 acquires the movement amount from the navigation sensor I/F 42 and acquires the angular velocity information from the gyro sensor I/F 45 (S109). As described above, the gyro sensor I/F 45 acquires the angular velocity information from the gyro sensor 31 at the timing generated by the print/sensor timing generation unit 43, and the navigation sensor I/F 42 is generated by the print/sensor timing generation unit 43. The amount of movement is acquired from the navigation sensor _S0 at the timing.

Next, the position calculation circuit 34 calculates the current position of the navigation sensor _S0 using the angular velocity information and the amount of movement (S110). Specifically, the position calculation circuit 34 adds the position (X, Y) calculated in the previous cycle to the movement amount (ΔX′, ΔY′) acquired this time and the movement distance calculated from the angular velocity information, and obtains the current , the position of the navigation sensor _S0 is calculated. If there is only the initial position and there is no position calculated last time, the current position of the navigation sensor S0 is calculated by adding the movement amount ( _ΔX ', ΔY') acquired this time and the movement distance calculated from the angular velocity information to the initial position. calculate.

Next, the position calculation circuit 34 calculates the current position of each nozzle 61 using the current position of the navigation sensor _S0 (S111).

In this way, since the angular velocity information and the movement amount are obtained at the same time or substantially at the same time by the print/sensor timing generation unit 43, the position of the nozzle 61 is calculated based on the rotation angle and the movement amount obtained at the timing when the rotation angle is detected. can. Therefore, even if the position of the nozzle 61 is calculated using information from sensors of different types, the accuracy of the position of the nozzle 61 is less likely to decrease.

Next, the CPU 33 controls the DMAC 38 to transmit the image data of the peripheral image of each nozzle 61 from the DRAM 29 to the image RAM 37 based on the calculated position of each nozzle 61 (S112). Note that the rotator 39 rotates the image according to the head position (how to hold the HMP 20, etc.) and the inclination of the IJ recording head 24 designated by the user.

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 current position of the nozzle 61 . Accordingly, the position calculation circuit 34 calculates the position of the nozzle 61 for each ink ejection cycle of the IJ recording head 24, which is shorter than the cycle in which the navigation sensor I/F 42 acquires the movement amount and the gyro sensor I/F 45 acquires the angular velocity information. Calculated.

The IJ recording head control unit 44 determines whether or not the position coordinates of the image element are included within a predetermined range from the position of the nozzle 61 calculated by the position calculation circuit 34 (S114).

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

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

When all the image data have been output, the CPU 33, for example, turns on the LED of the OPU 26 to inform the user that the printing has been completed (S117).

If the user determines that it is sufficient even if all the image data is not output, the user may press the print completion button, the OPU 26 may accept it, and the printing may end. After printing, the power can be turned off by the user, or the power can be turned off automatically when printing is finished.

<Image Formable Range with One Navigation Sensor>
An image formable range 501 when there is one navigation sensor will be described with reference to FIGS. FIG. 14 is an example of a diagram illustrating an image formable range 501 when two navigation sensors 30 are shown for comparison.

In FIG. 14(a), two navigation sensors 30 are arranged in parallel with the nozzle. FIG. 14(a) is a top view of the HMP 20. FIG. FIG. 14(b) shows a polygon 502 formed by the components (navigation sensors, nozzles) that must be on the print medium 12 in the arrangement of FIG. 14(a). Polygon 502 is an example of the size of the base. Let A [mm] be the distance from the nozzle 61 forming the polygon 502 to the right navigation sensors S ₀ and S ₁ , and B [mm] be the distance between the lower end of the nozzle 61 and the lower navigation sensor S ₁ .

FIG. 14(c) shows an image formable range 501 in the arrangement of FIG. 14(a). Since nozzle 61 is at the left and top end of polygon 502 , image formation is possible from the left top end of print medium 12 . On the other hand, since the distance from the nozzle 61 to the navigation sensors S ₀ and S ₁ on the right side is A [mm], the nozzle 61 cannot move further right than A [mm] from the right edge of the print medium 12 (image formation cannot be performed). ). Therefore, the right end of the image formable range 501 is located at a length A [mm] from the right end of the print medium 12 . Similarly, since the distance from the nozzle 61 to the lower navigation sensor S1 is B [ _mm ], the nozzle 61 cannot move below B [mm] from the bottom of the print medium 12 (image formation cannot be performed). Therefore, the lower end of the image formable range 501 is located at a length B [mm] from the lower end of the print medium 12 .

In FIG. 14(d), two navigation sensors S ₀ and S ₁ are arranged in series above and below the nozzle 61 . FIG. 14(e) shows a polygon 502 formed by the components (navigation sensors, nozzles) that must be on the print medium 12 in the arrangement of FIG. 14(d). Let _A [mm] be the length from the navigation sensor _S0 to S1 forming the polygon 502 .

FIG. 14(f) shows an image formable range 501 in the arrangement of FIG. 14(d). Since the vertical length of the print medium 12 is shorter than the length A [mm], the HMP 20 cannot form an image on the print medium 12 . Even if the HMP 20 is rotated by 90 degrees and arranged parallel to the horizontal direction of the print medium 12, the horizontal length of the print medium 12 is shorter than the length A [mm], so the HMP 20 does not transfer the image to the print medium 12. cannot be formed. Therefore, the image formable range 501 does not exist in FIG. 14(f).

In this way, if any one of the two navigation sensors 30 protrudes from the print medium 12, the HMP 20 cannot detect the position (the position becomes inaccurate). This causes the inconvenience of limiting the image formable range 501 on the medium 12 . Also, of course, even if the two navigation sensors 30 are above the print medium 12 , the HMP 20 cannot form an image if the IJ recording head 24 protrudes from the print medium 12 . Therefore, the two navigation sensors 30 and the IJ recording head 24 must be inside the print medium 12, limiting the image formable range 501. FIG. For this reason, in the conventional HMP 20, it was sometimes difficult for the user to use a large amount of paper space to form an image.

FIG. 15 is an example of a diagram illustrating an image formable range 501 when there is one navigation sensor 30 . In FIG. 15( a ), one navigation sensor S ₀ is arranged in series with the nozzle 61 . That is, the navigation sensor _S0 is arranged adjacently under the nozzle 61 and as close as possible. 15A is a top view of the HMP 20. FIG. FIG. 15(b) shows a polygon 502 formed by the components (navigation sensors, nozzles) that must be on the print medium 12 in the arrangement of FIG. 15(a). Let A [mm] be the distance between the lower end of the nozzle 61 forming the polygon 502 and the navigation sensor _S0 .

FIG. 15(c) shows an image formable range 501 in the arrangement of FIG. 15(a). Since the polygon 502 is substantially linear, the image can be formed from the upper left edge of the print medium 12 to the upper right edge of the print medium 12 . However, since the distance from the nozzle 61 to the lower navigation sensor _S0 is A [mm], the nozzle 61 cannot move downward from the lower side of the print medium 12 by more than A [mm] (image formation cannot be performed). Therefore, the lower end of the image formable range 501 is located at a length A [mm] from the lower end of the print medium 12 .

As is clear from a comparison of FIGS. 14(c) and 14(f) with FIG. 15(c), the use of one navigation sensor 30 greatly expands the image formable range 501 . In particular, since the upper half or more of the print medium 12 is the image formable range 501, the lower half of the print medium 12 becomes the image formable range 501 when the HMP 20 is inverted 180 degrees. Therefore, substantially the entire print medium 12 can be used as the image formable range 501 . The navigation sensor _S0 may be arranged above the IJ recording head 24 in FIG. 15(a). In this case, the image formable range 501 is from the lower end to the upper end of the print medium 12, leaving A [mm] (the image formable range 501 in FIG. 15C is vertically inverted).

In FIG. 15(d), one navigation sensor _S0 is arranged in a direction perpendicular to the direction in which the nozzles 61 are arranged. That is, the navigation sensor _S0 is placed adjacent to the right side of the nozzle 61 and as close as possible. FIG. 15(e) shows a polygon 502 formed by the components (navigation sensors, nozzles) that must be on the print medium 12 in the arrangement of FIG. 15(d). Let A [mm] be the distance between the nozzle forming the polygon 502 and the navigation sensor _S0 .

FIG. 15(f) shows an image formable range 501 in the arrangement of FIG. 15(d). Since the nozzles are located at the upper and left ends of the polygon 502 and there is no navigation sensor _S0 below the nozzles 61, it is possible to form an image from the upper end to the lower end of the left end of the print medium 12. FIG. However, since the distance from the nozzle 61 to the navigation sensor _S0 on the right side is A [mm], the nozzle 61 cannot be moved to the right by more than A [mm] from the right edge of the print medium 12 (image formation cannot be performed). Therefore, the right end of the image formable range 501 is located at a length A [mm] from the right end of the print medium 12 .

As is clear from a comparison of FIGS. 14(c) and 14(f) with FIG. 15(f), the use of one navigation sensor 30 greatly expands the image formable range 501 . In particular, since the left half or more of the print medium 12 is the image formable range 501, the right half of the print medium 12 becomes the image formable range 501 when the HMP 20 is inverted 180 degrees. Therefore, substantially the entire print medium 12 can be used as the image formable range 501 . Note that the navigation sensor _S0 may be arranged on the left side of the IJ recording head 24 in FIG. 15(d). In this case, the image formable range 501 extends from the right end of the print medium 12 to the left end, leaving A [mm] (the image formable range 501 in FIG. 15F is horizontally reversed).

Further, as shown in FIG. 16, the IJ recording head 24 may be provided with a navigation sensor _S0 . FIG. 16 is an example of a diagram for explaining an arrangement example of the navigation sensor _S0 . The navigation sensor S ₀ is arranged, for example, in a hole provided in a bracket (holding member) surrounding the nozzle 61 . Alternatively, if the navigation sensor _S0 does not have to be near the bottom surface, the navigation sensor _S0 may be installed inside the housing rather than the bottom surface. In this case, since the navigation sensor _S0 and the nozzle 61 do not have to be arranged on the same plane, the distance between the navigation sensor _S0 and the nozzle 61 can be shortened.

<Gyro sensor placement example>
It is known that the gyro sensor 31 is preferably arranged closer to the center of rotation. However, the center of rotation of the HMP 20 is often near the user's elbow rather than the center of the HMP 20 or the center of gravity. This is because the user causes the HMP 20 to scan around the elbow. Therefore, the gyro sensor 31 is preferably arranged as shown in FIG.

FIG. 17A is an example of a diagram showing an arrangement example of the gyro sensor 31. FIG. The gyro sensor 31 is arranged on the front side of the housing of the HMP 20 and substantially in the center in the width direction. This is because it is closest to the user's elbow. With such an arrangement, the gyro sensor 31 is arranged near the center of rotation, so it is expected that the accuracy of the detected angular velocity will be improved. In some cases, the user rotates the HMP 20 by 90 degrees or 180 degrees for scanning. Considering this point, it is preferable that one or more gyro sensors 31 are installed at the end of the HMP 20 when viewed from above the HMP 20 .

On the other hand, when the HMP 20 is a rigid body, it is necessary to place it on the front side of the housing in order to obtain the required accuracy. However, the vicinity of the portion of the HMP 20 that the user can touch may deform due to the weight applied when the user scans the HMP 20 . If such deformation is transmitted to the gyro sensor 31, there is a risk that noise will enter the angular velocity.

Therefore, it is preferable that the gyro sensor 31 is arranged in a state that the user cannot touch inside the housing of the HMP 20 and that the gyro sensor 31 is difficult to deform. Specifically, it is arranged on the printed circuit board 70 near the bottom surface of the HMP 20 . The printed circuit board 70 is a plate-like component made of resin or the like, and is a component on which electronic components, integrated circuits (ICs), and metal wiring that connects them are mounted at high density. Printed circuit boards are sometimes called PWBs or electronic boards. By arranging in this way, even if the HMP 20 is deformed by a general human force, it is difficult for it to be transmitted to the gyro sensor 31, so that it is possible to suppress noise from entering the angular velocity.

Moreover, it is known that the angular velocity of the gyro sensor 31 is affected by temperature changes, and it is preferable that the gyro sensor 31 be arranged in a place where temperature changes are small within the housing. Circuits through which a large amount of current flows, such as SoCs, LSIs such as ASICs/FPGAs, and power supplies, are heating elements that generate heat during operation. Therefore, temperature changes are large in the vicinity of these circuits. For this reason, it is preferable that the gyro sensor 31 is arranged as far away as possible from the SoC 50 and the ASIC/FPGA 40 as shown in FIG. 17(b). In FIG. 17B, the gyro sensor 31 is arranged on a printed circuit board 70 different from at least SoC and ASIC/FPGA.

Since the human hand is also a heat source, the gyro sensor 31 is preferably arranged near the bottom surface from this point of view as well.

If the temperature characteristic is linear or can be investigated in advance, the temperature may be measured with a temperature sensor and the angular velocity may be corrected according to the temperature characteristic.

It is also effective to mount the navigation sensor _S0 and the gyro sensor 31 on the same printed circuit board 70 . In FIG. 17(c), the gyro sensor 31 on the front side of the HMP 20 and the navigation sensor _S0 are arranged on one printed circuit board 70. In FIG. Even if the positions of the gyro sensor 31 and the navigation sensor _S0 are close to each other, it does not particularly contribute to reducing the size of the bottom surface of the HMP 20 . However, when the gyro sensor 31 has three axes, it is possible to detect changes in posture other than the rotation angle with respect to the axis perpendicular to the print medium 12, so there are advantages as follows.

FIG. 18 is an example of a diagram illustrating the posture of the HMP 20 detected by the gyro sensor 31. As shown in FIG. If the gyro sensor 31 has three axes, it can detect angular velocities in the yaw direction, roll direction, and pitch direction. Of these, the angular velocity in the yaw direction is used to calculate the position of the navigation sensor. If roll and pitch angular velocities are detected during imaging, the navigation sensor S ₀ may have moved away from the print media 12 . When the navigation sensor _S0 and the gyro sensor 31 are arranged on the same printed circuit board 70, it is assumed that the same angular velocity as the angular velocity in the roll direction and the pitch direction detected by the gyro sensor 31 acts on the navigation sensor _S0 . Therefore, it is easy to detect that an angular velocity in the roll direction or the pitch direction has occurred that causes the navigation sensor _S0 to move away from the print medium 12 .

Therefore, when the navigation sensor _S0 and the gyro sensor 31 are arranged on the same printed circuit board 70, it becomes easier to detect whether the navigation sensor _S0 is separated from the print medium 12 by using the triaxial gyro sensor 31. .

<Processing when installing the gyro sensor 31>
Also, if the gyro sensor 31 can detect three-axis angular velocities, the HMP 20 and the like can detect the mounting accuracy when the gyro sensor 31 is mounted on the HMP 20 . The gyro sensor 31 is preferably assembled horizontally to the HMP 20 as much as possible. By doing so, all changes in the attitude of the HMP 20 in the yaw direction can be detected as angular velocities. However, in actual assembly, slight deviations from the horizontal may occur, and in this case, even if the user rotates the HMP 20 only horizontally, the angular velocity in the roll or pitch direction may be detected.

Thus, the user operates the HMP 20, for example, in a test mode, causing the HMP 20 to scan horizontally. The HMP 20 detects the angular velocity in the roll or pitch direction, and determines how much the gyro sensor 31 is tilted with respect to the HMP 20 . If the degree of inclination is known, the angular velocity in the yaw direction can be corrected.

Also, when the gyro sensor 31 detects angular velocity in only one axis (yaw direction), a jig that can be moved in the range of 0 degrees→90 degrees→0 degrees is prepared. The HMP 20 detects angles when the user is moving the jig in the range of 0 degrees→90 degrees→0 degrees. If the detected angle is not 90 degrees, a correction coefficient is calculated so that the angle becomes 90 degrees and stored inside the device. Therefore, the angular velocity can be corrected during actual image formation.

When the user scans the HMP 20 over the print medium 12 , the bottom surface may be slightly lifted from the print medium 12 . Since the navigation sensor 30 also floats, the position detected by the navigation sensor 30 also becomes inaccurate. The positional error due to this floating can be ignored, but the resolution of the moving amount changes greatly.

The resolution of the optical navigation sensor 30 is expressed in CPI (Count Per Inch). This means the number counted while the navigation sensor 30 is moved one inch, the higher the number the higher the resolution.

As shown in FIG. 19, the navigation sensor 30 changes the resolution of the amount of movement depending on the distance between the paper surface and the navigation sensor 30 . FIG. 19 is an example of a diagram showing changes in the resolution between the sensor inter-paper distance and the amount of movement. It can be seen that the resolution decreases as the distance between sensor papers increases. This is because the navigation sensor 30 optically detects the edge of the print medium 12, and the closer the sensor-to-paper distance is, the more advantageous it is to detect the edge (it is easier to detect a minute edge).

Since the navigation sensor 30 has such properties, the manufacturer of the HMP 20 detects the amount of movement in X and Y at a fixed resolution (CPI) in accordance with the mounting position of the navigation sensor 30 in the HMP 20 .

Therefore, if the HMP 20 floats above the printing medium 12, the amount of movement will also deviate (only the amount of movement smaller than the actual amount of movement can be detected), so some kind of correction is preferably performed. In this embodiment, the HMP 20 that suppresses the resolution of the moving amount due to the floating of the HMP 20 from the print medium 12 will be described.

FIG. 20(a) is a view showing the mounting position of the navigation sensor 30 from above the HMP 20, and FIG. 20(b) is a view for explaining the rotation of the navigation sensor 30 about three axes.

As shown in FIG. 20B, the print medium 12 is placed on the XY plane, and the direction perpendicular to the print medium 12 is the Z axis. As described in the first embodiment, the position of the nozzle 61 is calculated from the rotation angle about the Z-axis. On the other hand, how far the navigation sensor 30 is above the print medium 12 is affected by at least one of the rotation angle about the X-axis and the rotation angle about the Y-axis. It should be noted that it is not necessary to consider that the entire navigation sensor 30 is translated in the Z-axis direction. This is because, in general, users do not use the navigation sensor 30 in such a manner, and an error occurs when the entire navigation sensor 30 floats significantly.

Assuming that the rotation angle about the X-axis and the rotation angle about the Y-axis at the start of printing are zero, the gyro sensor 31 detects the rotation angle about the X-axis (YZ plane) and the rotation angle about the Y-axis (ZZ plane). By detecting , the position calculation circuit 34 can detect floating during print scanning.

Next, a method of calculating the floating amount will be described with reference to FIG. FIG. 21 is an example of a diagram for explaining the floating amount of the navigation sensor 30 from the print medium 12. FIG. FIG. 21(a) is a side view of the navigation sensor 30 as seen from the Y-axis direction of FIG. 20(a). FIG. 21(b) shows the floating amount when the navigation sensor 30 rotates (floats) around the left end, and FIG. 21(c) shows the floating amount when the navigation sensor 30 rotates (floats) around the right end. shows the amount of floating.

Let L1 be the distance from the left end of the housing of the HMP 20 of the navigation sensor 30, and L2 be the distance from the right end. Since the direction of rotation about the Y-axis is opposite depending on whether the rotation is about the left end or the right end, the position calculation circuit 34 determines the direction of rotation (left end axis rotation and right end rotation) depending on whether the rotation angle is positive or negative. axis rotation) can be determined. In the case of left-end shaft rotation, the floating amount is calculated as shown in FIG. 21(b), and in the case of right-end shaft rotation, the floating amount is calculated as shown in FIG. 21(c).

Let α be the rotation angle detected by the gyro sensor 31 . After the direction of rotation is determined, α may be an absolute value. From FIG. 21(b), the floating amount in the case of left end shaft rotation is as follows.
L1 sinα
Similarly, from FIG. 21(c), the floating amount in the case of left end shaft rotation is as follows.
L2 sinα
21(a) and 21(b) are caused by rotation about the Y-axis, but the HMP 20 also rotates about the X-axis. Therefore, the position calculation circuit 34 also calculates the floating amount caused by rotation about the X axis. From the above, the final floating amount is calculated as the total (sum) of the floating amount due to the X-axis center rotation and the floating amount due to the Y-axis center rotation.

Floating amount of navigation sensor 30
= Floating amount (X-axis center rotation) + Floating amount (Y-axis center rotation)
Since the navigation sensor 30 floats, the navigation sensor 30 moves not only in the height direction but also in the lateral direction. The amount of movement is "L1-L1cosα" and "L2-L2cosα". However, in the actual scanning of the HMP 20, the floating amount is small and can be ignored.

However, the difference in the resolution of the moving amount due to the change in the distance between the printing medium 12 and the navigation sensor 30 caused by the floating cannot be ignored. When the navigation sensor 30 is slightly lifted during scanning, the resolution of the movement amount output by the navigation sensor 30 changes greatly (becomes smaller). becomes smaller.

Therefore, the position calculation circuit 34 utilizes the proportional relationship between the distance between the sensor papers and the resolution of the moving amount shown in FIG. 19 to convert the floating amount into a change in resolution, thereby correcting the moving amount. A specific example will be used for explanation.

For example, assume that the relationship between the distance between the sensor sheets of the navigation sensor 30 and the resolution of the movement amount is as follows.
Equivalent to 4000cpi when the distance between the print medium and the sensor is 2 mm. Equivalent to 3500 cpi when the distance between the print medium and the sensor is 2.1 mm. When the distance between the print medium and the sensor is 2 mm, the amount of movement output by the navigation sensor 30 when the navigation sensor 30 moves by 1 mm is 157 counts. This means that the amount of movement output by the navigation sensor 30 drops to 137 counts when the navigation sensor 30 moves 1 mm. Therefore, the amount of movement of the navigation sensor 30 is calculated to be smaller than the actual amount of movement, and the position of the navigation sensor 30 is shifted.

However, as shown in FIG. 19, the HMP 20 holds the proportional relationship between the distance between the sensor papers and the resolution of the movement amount, so that the position calculation circuit 34 can estimate the resolution of the movement amount from the floating amount. be possible.

For example, the relationship between the distance between the sensor papers and the resolution of the movement amount as shown in FIG. 19 is represented by the formula y=ax+b. y is the resolution of the movement amount, x is the inter-sensor paper distance, and a and b are coefficients. Since x can be obtained from the amount of floating, the resolution of the amount of movement can be obtained. The movement amount (count number) detected when the navigation sensor 30 is floating is multiplied by the value obtained by dividing the resolution of the movement amount when the floating amount is zero by the obtained movement amount resolution. As a result, even if the navigation sensor 30 floats, it can be corrected to the amount of movement when the amount of float is zero.

Note that since the proportional relationship between the sensor inter-paper distance and the resolution of the movement amount may change depending on the paper type, it is preferable to maintain the proportional relationship between the sensor inter-paper distance and the resolution of the movement amount according to the paper type.

FIG. 22 is an example of a flowchart for explaining the operation procedure of the image data output device 11 and the HMP 20. As shown in FIG. In the explanation of FIG. 22, mainly the difference from FIG. 13 will be explained.

First, in step S106, the CPU 33 stores, for example, the initial position of coordinates (0, 0) and the initial angle (X, Y axes) of the gyro sensor 31 in the DRAM 29 or a register of the CPU 33 (S106). That is, the CPU 33 reads angular velocity information from the gyro sensor 31 .

In step S110, the position calculation circuit 34 uses the angular velocity information and the amount of movement to calculate the current position of the navigation sensor _S0 . Based on this, the floating amount is calculated and the position of the navigation sensor 30 is corrected.

As described above, according to this embodiment, the position of the navigation sensor 30 can be corrected even if the resolution of the movement amount changes due to the floating of the navigation sensor 30 .

<Other application examples>
Although the best mode for carrying out the present invention has been described above using examples, the present invention is by no means limited to such examples, and various modifications can be made without departing from the scope of the present invention. and substitutions can be added.

For example, the components 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, in the present embodiment, an image is formed by ejecting ink, but an image may be formed by irradiating visible light, ultraviolet light, infrared light, laser light, or the like. In this case, the print medium 12 is, for example, one that reacts to heat or light. Alternatively, a transparent liquid may be discharged. In this case, visible information is obtained when light in a specific wavelength range is irradiated. Alternatively, metal paste, resin, or the like may be discharged.

Further, in this embodiment, the orientation of the print medium 12 is detected by the gyro sensor 31, but the horizontal orientation (orientation) can also be detected by the geomagnetic sensor.

Also, the number of gyro sensors 31 is not limited to one, and two or more may be installed.

The navigation sensor _S0 is an example of movement amount detection means, the gyro sensor 31 is an example of attitude detection means, and the position calculation circuit 34 is an example of position calculation means. The print/sensor timing generation unit 43 is an example of timing notification means, the IJ recording head control unit 44 and the like are an example of droplet ejection means, and the HMP 20 is an example of a droplet ejection device. The CPU 33, the position calculation circuit 34, and the gyro sensor 31 are examples of floating amount calculation means.

Further, the position detection device is a device of the HMP 20 that has at least the functions necessary for position calculation. For example, it has a navigation sensor S ₀ , a gyro sensor 31 , a position calculation circuit 34 and a CPU 33 . In other words, the HMP 20, which does not have the functions required for image formation, is the position detection device. Also, a device on which the position detection device is mounted is a mounted object, and the HMP 20 is an example of the mounted object.

REFERENCE SIGNS LIST 11 image data output device 12 print medium 25 controller 30 navigation sensor 31 gyro sensor 33 CPU
34 position calculation circuit 42 navigation sensor I/F
43 sensor timing generator 45 gyro sensor I/F
61 nozzle 70 printed circuit board

Japanese Patent Publication No. 2010-522650

Claims (6)

An image forming apparatus that is moved on a medium and forms an image in accordance with the movement on the medium,
a movement amount detection means for detecting a movement amount of the image forming apparatus in movement on the medium;
attitude detection means for detecting an amount of change in attitude of the image forming apparatus according to movement on the medium;
and image forming means for forming an image on the medium ,
calculating the position of the image forming means on the medium based on the amount of movement and the amount of change in posture, forming an image if there is an image element corresponding to the calculated position, and forming the image if the image has already been formed; making the position not to form the image,
The movement amount detection means and the attitude detection means are realized by different sensors,
In the calculation of the position, the amount of movement on the medium output by the amount-of-movement detection means is converted into coordinates on the medium using the amount of change in attitude obtained by the attitude detection means. Image forming device. the image forming means for forming an image on the medium;
Based on whether the position of the image forming means on the medium based on the amount of movement and the amount of change in the attitude is within an allowable range including a target position indicating a formation destination on the medium of pixels constituting the image. 2. The image forming apparatus according to claim 1, further comprising control means for controlling formation of said image by said image forming means. The control means is
3. The image forming apparatus according to claim 2, wherein when the position of said image forming means is within an allowable range from said target position, said image forming means is controlled to form said image. position calculation means for calculating a position of the image forming means based on the amount of movement and the amount of change in posture;
The position calculation means can predict the position of the image forming means on the medium at the next image forming timing,
The control means prepares for forming the image by the image forming means based on the relationship between the position of the image forming means predicted by the position calculating means and an allowable range including the target position. 4. The image forming apparatus according to claim 2 or 3. The movement amount detection means is a navigation sensor that detects the movement amount of the image forming apparatus by irradiating the surface of the medium with light at predetermined timings and receiving reflected light from the medium,
5. The image forming apparatus according to claim 1, wherein said posture detecting means is a gyro sensor for detecting angular velocity when said image forming apparatus rotates about an axis perpendicular to said medium. Device. 6. The image forming apparatus according to claim 1, wherein the image forming apparatus is a handy mobile printer that forms an image by allowing a user to scan the medium.

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