JP6996184B2 - Liquid discharge device and liquid discharge method - Google Patents

Description

The present invention relates to a device for discharging a liquid and a method for discharging the liquid.

A serial inkjet printer, which is one of the recording devices, includes a carriage equipped with a recording head that can be reciprocated in the main scanning direction orthogonal to the transport direction of the paper as a recording medium on the platen. In such an inkjet printer, the carriage is reciprocated while transporting the paper on the platen, and ink droplets are ejected from the recording head to record on the paper. Therefore, the gap between the ink ejection surface of the recording head and the paper transport surface of the platen greatly affects the recording accuracy.

For example, Patent Document 1 discloses a configuration in which the gap is detected and the ink ejection timing is set (corrected) based on the detection result.

However, there is a problem that sufficient image quality cannot be provided only by setting the ejection timing based on the gap.

It is an object of the present invention to provide a device for discharging a liquid and a liquid discharging method capable of providing sufficient image quality.

In order to solve the above-mentioned problems and achieve the object, the present invention relatively moves the carriage equipped with the head for discharging the liquid to the ejected object, the carriage, and the ejected object. It was obtained by the measurement unit that measures the distance between the drive unit, the carriage, and the ejected object, the image pickup unit that images the ejected object, the measurement results of the measurement unit, and the image pickup by the image pickup unit. A setting unit for setting the discharge performance of the liquid from the head based on the captured image is provided , and the setting unit includes the discharge timing of the liquid from the head based on the measurement result of the measurement unit. Based on the pattern captured image showing the captured image obtained by imaging the pattern image formed on the ejected object after the setting by the first setting unit and the first setting unit. A second setting unit for resetting the discharge timing of the liquid from the head or setting the size of the droplet is included .

According to the present invention, sufficient image quality can be provided.

FIG. 1 is a diagram showing an overall configuration of an inkjet recording device according to an embodiment. FIG. 2 is a top view of the carriage. FIG. 3 is a perspective view showing the appearance of the image pickup apparatus. FIG. 4 is an exploded perspective view of the image pickup apparatus. FIG. 5 is a vertical cross-sectional view of the image pickup apparatus viewed from the X1 direction in FIG. FIG. 6 is a vertical cross-sectional view of the image pickup apparatus viewed from the X2 direction in FIG. FIG. 7 is a diagram showing a specific example of the reference chart. FIG. 8 is a block diagram showing a configuration example of a control mechanism of an inkjet recording device. FIG. 9 is a diagram showing an example of the function of the control FPGA. FIG. 10 is a diagram for explaining a setting method by the first setting unit. FIG. 11 is a diagram for explaining a setting method by the second setting unit. FIG. 12 is a flowchart showing an example of control of the embodiment. FIG. 13 is a diagram showing an example of a pattern image. FIG. 14 is a block diagram showing an example of the function of the image pickup device of the modified example. FIG. 15 is a diagram showing an example of an image captured by the sensor unit. FIG. 16 is a diagram showing an example of an image captured by the sensor unit. FIG. 17 is a diagram showing an example of an image captured by the sensor unit. FIG. 18 is a diagram illustrating a method of calculating a distance based on the ratio of the size of the low-luminance region to the size of the high-luminance region. FIG. 19 is a diagram illustrating a method of calculating a distance based on the ratio of the size of the low-luminance region to the size of the high-luminance region. FIG. 20 is a diagram illustrating a method of calculating a distance based on the ratio of the size of the low-luminance region to the size of the high-luminance region. FIG. 21 is a flowchart showing a procedure of distance measurement by an image pickup device of a modified example.

Hereinafter, embodiments of a liquid discharge device and a liquid discharge method according to the present invention will be described in detail with reference to the accompanying drawings. In the present application, the "device for discharging a liquid" is a device including a head for discharging a liquid and driving the head to discharge the liquid. The "device for discharging a liquid" includes not only a device capable of discharging a liquid to an object to be discharged, but also a device for discharging the liquid into the air or into the liquid. For example, an image forming apparatus, a three-dimensional modeling apparatus, a processing liquid coating apparatus, an injection granulation apparatus, and the like are applicable. In the following, as an example of the “device for ejecting liquid”, an example of application of the image forming device to one inkjet recording device will be shown. In the following description of the inkjet recording apparatus, "ink (ink droplet)" which is an example of a recording liquid is an example of the above "liquid", and "recording head" is an example of the above "head", which is an example of a recording medium. "Paper" is shown as an example of the above-mentioned "ejected object".

FIG. 1 is a diagram showing the overall configuration of the inkjet recording apparatus 1 according to the embodiment. The inkjet recording apparatus 1 forms an image while scanning a carriage 15 on which a recording head 16 (described in FIG. 2) is mounted in the width direction of a sheet (paper), and after one or a plurality of scans are completed, the sheet is formed. It is a so-called serial type inkjet recording device that transports the next recording line and forms the next recording line.

As shown in FIG. 1, the inkjet recording apparatus 1 includes an image forming unit 2, a sheet conveying unit 3, and a roll paper storage unit 4, and each of these units is arranged inside the apparatus main body 1a. There is. In the image forming portion 2, the guide rod 13 and the guide rail 14 are hung on both side plates (not shown), and the carriage 15 is slidably held by the guide rod 13 and the guide rail 14 in the direction of the arrow A. The carriage 15 is equipped with a recording head 16 (see FIG. 2) that ejects ink droplets of each color of black (K), yellow (Y), magenta (M), and cyan (C).

The main scanning mechanism 10 includes a carriage drive motor 210 arranged on one side in the width direction of the seat, a drive pulley 220 rotationally driven by the carriage drive motor 210, and a driven pulley 230 arranged on the other side in the width direction of the seat. And a belt member 240 hung between the drive pulley 220 and the driven pulley 230. Tension is applied to the driven pulley 230 outward by a tension spring or the like, that is, in a direction away from the drive pulley 220.

A part of the belt member 240 is fixedly held by the belt fixing portion provided on the back surface side of the carriage 15, so that the carriage 15 is pulled in the seat width direction. Further, in order to detect the main scanning position of the carriage 15, the encoder sheet is arranged along the sheet width direction of the carriage 15.

The main scanning position of the carriage 15 is detected by reading the encoder sheet by the encoder sensor provided on the carriage 15. In the recording area of the main scanning area of the carriage 15, the roll paper 300 is intermittently conveyed by the sheet conveying section 3 in the direction orthogonal to the sheet width direction, that is, in the sheet conveying direction (direction indicated by arrow B in the drawing). Will be done. Further, in the area outside the carriage movement area in the seat width direction or in one end side area of the main scanning area, a main cartridge 18 containing ink of each color supplied to the sub tank of the recording head 16 is provided with respect to the apparatus main body 1a. It is attached detachably. Further, although not shown, ink droplets that do not contribute to image recording because the thickened ink is discharged on one end side of the carriage movement region, that is, the empty ejection position side (left side in the figure). An empty ejection receiver is provided to receive ink droplets when performing an empty ejection operation.

Each recording head 16 is adapted to perform empty ejection at the empty ejection position in order to maintain and recover the ejection performance when a predetermined condition is satisfied. Further, a maintenance / recovery mechanism 19 for maintaining / recovering the recording head 16 is arranged on the other end side of the carriage movement region, that is, on the carriage home position side (right side in the drawing). The maintenance / recovery mechanism 19 includes caps for capping each nozzle surface of the recording head 16, a wiper blade which is a blade member for wiping the nozzle surface, and the like.

Depending on the specifications of the device, for example, an empty discharge receiver may be provided on the carriage home position side and included in the maintenance / recovery mechanism 19 like the cap and the wiper blade, or the carriage home position side and the empty discharge position side. There may be a configuration in which an empty discharge receiver is provided in both of the above.

The roll paper storage unit 4 is a paper feeding means, and the roll paper 300 is set as a sheet for image recording. Roll papers having different sizes in the sheet width direction can be set in the roll paper storage unit 4.

The roll paper 300 is accommodated in the roll paper storage unit 4 by mounting flanges 310 on the paper shaft from both sides and placing the flange 310 on the flange receiver 320. A support roller (not shown) is provided inside the flange receiver 320, and when the support roller comes into contact with the outer circumference of the flange 310, the flange 310 rotates and the roll paper 300 is sent out to the sheet transport path. However, the device configuration is not limited to the above, and can be applied to a serial type inkjet printer that supports only a small cut sheet.

FIG. 2 is a top view of the carriage 15. In FIG. 2, reference numeral 41 denotes a measuring unit (hereinafter, may be referred to as a gap measuring unit 41) for measuring the distance between the carriage 15 and the sheet (discharged object), such as an optical sensor type displacement meter, for recording. The distance to the seat is measured at the same height as the discharge port surface of the head 16.

As shown in FIG. 2, the carriage 15 has a recording head 16y for ejecting yellow (Y) ink, a recording head 16m for ejecting magenta (M) ink, and a recording for ejecting cyan (C) ink. A head 16c and a recording head 16k for ejecting black (K) ink are mounted. These are collectively referred to as a recording head 16.

Further, as shown in FIG. 2, an image pickup device (an example of an image pickup unit) 42 for capturing a pattern image P printed on a sheet is supported by the carriage 15. As will be described in detail later, the ink ejection timing of the recording head 16 is set according to the gap measured by the gap measuring unit 41, and the printing result after the setting is captured by the image pickup device 42. If it is determined that sufficient quality can be ensured based on the captured image obtained by the imaging, the adjustment of the ejection performance of the recording head 16 ends there. On the contrary, if it is determined that it is not sufficient, further setting (adjustment) is carried out. The image pickup by the image pickup apparatus 42 is not limited to the order as described above. For example, the image pickup is performed before the correction of the ink ejection timing according to the gap is performed, and the quality is confirmed. Is also good. Further, the arrangement of the gap measuring unit 41 and the image pickup device 42 with respect to the carriage 15 is not limited to the example of FIG.

Next, a mechanical configuration example of the image pickup apparatus 42 of the present embodiment will be described with reference to FIGS. 3 to 6. 3 is a perspective view showing the appearance of the image pickup device 42, FIG. 4 is an exploded perspective view of the image pickup device 42, FIG. 5 is a vertical sectional view of the image pickup device 42 as seen from the X1 direction in FIG. 3, and FIG. It is a vertical sectional view of the image pickup apparatus 42 seen from the X2 direction in FIG.

As shown in FIGS. 3 and 4, the image pickup apparatus 42 includes a housing 21 in which a mounting piece 22 is integrally formed. The housing 21 has, for example, bottom plate portions 21a and top plate portions 21b facing each other at predetermined intervals, and side wall portions 21c, 21d, 21e, 21f connecting these bottom plate portions 21a and the top plate portion 21b. The bottom plate portion 21a and the side wall portions 21d, 21e, 21f of the housing 21 are integrally formed together with the mounting piece 22 by, for example, molding, whereas the top plate portion 21b and the side wall portion 21c are detachable. To. FIG. 4 shows a state in which the top plate portion 21b and the side wall portion 21c are removed.

The image pickup device 42 is, for example, fastened to the side surface portion of the carriage 15 by using a fastening member such as a screw in a state where the side wall portion 21e of the housing 21 and the mounting piece 22 are abutted against the side surface portion of the carriage 15. , Attached to the carriage 15. At this time, as shown in FIGS. 5 and 6, the image pickup apparatus 42 is attached to the carriage 15 so that the bottom plate portion 21a of the housing 21 faces the seat in a substantially parallel state via the gap d. The size of the gap d corresponds to the distance between the subject and the housing 21 imaged by the sensor unit 25 described later. This distance varies, for example, due to the difference in the thickness of the sheet and the influence of the unevenness of the platen surface that supports the sheet.

On the bottom plate portion 21a of the housing 21 facing the sheet, a subject outside the housing 21 (when measuring the color of the pattern image P, the pattern image P formed on the sheet) is imaged from the inside of the housing 21. An opening 23 is provided to enable this. Further, a reference chart 40 is arranged on the inner surface side of the bottom plate portion 21a of the housing 21 so as to be adjacent to the opening 23 via the support member 33. The reference chart 40 is imaged together with the pattern image P by the sensor unit 25 described later when the color measurement of the pattern image P and the acquisition of the RGB value are performed. The details of the reference chart 40 will be described later.

On the other hand, the circuit board 24 is arranged on the top plate portion 21b side inside the housing 21. Further, a sensor unit 25 for capturing an image is arranged between the top plate portion 21b of the housing 21 and the circuit board 24. As shown in FIG. 5, the sensor unit 25 connects a two-dimensional image sensor 25a such as a CCD sensor or a CMOS sensor and an optical image of the imaging range of the sensor unit 25 to the light receiving surface (imaging region) of the two-dimensional image sensor 25a. It is provided with a lens 25b for imagery.

The sensor unit 25 is held by, for example, a sensor holder 26 integrally formed with the side wall portion 21e of the housing 21. The sensor holder 26 is provided with a ring portion 26a at a position facing the through hole 24a formed in the circuit board 24. The ring portion 26a has a through hole having a size that follows the outer shape of the protruding portion of the sensor unit 25 on the lens 25b side. The sensor unit 25 inserts the protruding portion on the lens 25b side into the ring portion 26a of the sensor holder 26 so that the lens 25b faces the bottom plate portion 21a side of the housing 21 via the through hole 24a of the circuit board 24. , Held by the sensor holder 26.

At this time, in the sensor unit 25, the optical axis shown by the alternate long and short dash line in FIG. 5 is substantially perpendicular to the bottom plate portion 21a of the housing 21, and the opening 23 and the reference chart 40 described later are included in the imaging range. It is held in a positioned state by the sensor holder 26 so as to be. As a result, the sensor unit 25 captures a subject (pattern image P formed on the sheet) outside the housing 21 in a part of the imaging region of the two-dimensional image sensor 25a through the opening 23, and at the same time, the sensor unit 25 images the subject (pattern image P formed on the sheet). The reference chart 40 arranged inside the housing 21 can be imaged in another part of the image pickup area of the two-dimensional image sensor 25a.

The sensor unit 25 is electrically connected to the circuit board 24 on which various electronic components are mounted, for example, via a flexible cable. Further, the circuit board 24 is provided with an external connection connector 27 to which a connection cable for connecting the image pickup device 42 to the main control board 100 (see FIG. 8 described later) of the inkjet recording device 1 described later is attached. ing.

Further, inside the housing 21, a light source 28 for illuminating the imaging range substantially uniformly at the time of imaging by the sensor unit 25 is provided. As the light source 28, for example, an LED (Light Emitting Diode) is used. In the present embodiment, as shown in FIG. 6, two LEDs are used as light sources evenly arranged in a direction orthogonal to the direction in which the opening 23 and the reference chart 40 are arranged with the center of the lens 25b of the sensor unit 25 as a reference. It is used as 28.

The two LEDs used as the light source 28 are mounted, for example, on the surface of the circuit board 24 on the bottom plate portion 21a side. However, the light source 28 may be arranged at a position where the imaging range of the sensor unit 25 can be illuminated substantially uniformly by diffused light, and may not necessarily be directly mounted on the circuit board 24. Further, in the present embodiment, the LED is used as the light source 28, but the type of the light source 28 is not limited to the LED. For example, an organic EL or the like may be used as the light source 28. When the organic EL is used as the light source 28, illumination light close to the spectral distribution of sunlight can be obtained, so that improvement in color measurement accuracy can be expected.

Further, inside the housing 21, an optical path between the sensor unit 25 and a subject (pattern image P formed on the sheet) outside the housing 21 imaged through the opening 23 by the sensor unit 25. An optical path length changing member 29 is arranged inside. The optical path length changing member 29 is an optical element having a refractive index n having sufficient transmittance for the light of the light source 28. The optical path length changing member 29 has a function of bringing the image plane of the optical image of the subject outside the housing 21 closer to the image plane of the optical image of the reference chart 40 inside the housing 21. That is, in the image pickup apparatus 42 of the present embodiment, the optical path length is changed by arranging the optical path length changing member 29 in the optical path between the sensor unit 25 and the subject outside the housing 21, and the subject outside the housing 21 is used. The image plane of the optical image of the pattern image P and the image plane of the reference chart 40 inside the housing 21 are both aligned with the light receiving surface of the two-dimensional image sensor 25a of the sensor unit 25. As a result, the sensor unit 25 can capture an image in which both the subject outside the housing 21 and the reference chart 40 inside the housing 21 are in focus.

As shown in FIG. 5, for example, in the optical path length changing member 29, both ends of the surface on the bottom plate portion 21a side are supported by a pair of ribs 30 and 31. Further, by arranging the pressing member 32 between the surface of the optical path length changing member 29 on the top plate portion 21b side and the circuit board 24, the optical path length changing member 29 does not move inside the housing 21. There is. Since the optical path length changing member 29 is arranged so as to close the opening 23 provided in the bottom plate portion 21a of the housing 21, the ink mist that enters the inside of the housing 21 from the outside of the housing 21 via the opening 23. It also has a function of preventing impurities such as dust and dirt from adhering to the sensor unit 25, the light source 28, the reference chart 40, and the like.

When the image pickup device 42 of the present embodiment measures the color of the pattern image P, the light source 28 provided inside the housing 21 is turned on, and the light of the light source 28 is emitted onto the sheet outside the housing 21. An image is taken by the sensor unit 25 while the formed pattern image P is irradiated.

The mechanical configuration of the image pickup apparatus 42 described above is merely an example, and is not limited to this. In the image pickup apparatus 42 of the present embodiment, at least while the light source 28 provided inside the housing 21 is lit, the sensor unit 25 provided inside the housing 21 causes the outside of the housing 21 to be connected. Any configuration may be used as long as the subject is imaged through the opening 23, and various modifications and changes can be made to the above configuration. For example, in the image pickup apparatus 42 described above, the reference chart 40 is arranged on the inner surface side of the bottom plate portion 21a of the housing 21, but the opening 23 is located at the position where the reference chart 40 of the bottom plate portion 21a of the housing 21 is arranged. In addition to providing an opening different from that of the housing 21, the reference chart 40 may be attached to the position where the opening is provided from the outside of the housing 21. In this case, the sensor unit 25 captures the pattern image P formed on the sheet through the opening 23, and is outside the bottom plate portion 21a of the housing 21 via an opening different from the opening 23. The reference chart 40 attached from is imaged. In this example, there is an advantage that the reference chart 40 can be easily replaced when a defect such as dirt occurs.

Next, a specific example of the reference chart 40 arranged in the housing 21 of the image pickup apparatus 42 will be described with reference to FIG. 7. FIG. 7 is a diagram showing a specific example of the reference chart 40.

The reference chart 40 shown in FIG. 7 has a plurality of reference patch rows 410 to 440 in which reference patches for color measurement are arranged, a pattern row 460 for dot diameter measurement, a distance measurement line 450, and a chart position specifying marker 470. ..

The reference patch rows 410 to 440 include a reference patch row 410 in which the YMCK primary color reference patches are arranged in gradation order, a reference patch row 420 in which RGB secondary color reference patches are arranged in gradation order, and a gray scale. Includes a reference patch sequence (achromatic gradation pattern) 430 in which the reference patches of the above are arranged in the order of gradation, and a reference patch sequence 440 in which the reference patches of the tertiary color are arranged. The dot diameter measurement pattern sequence 460 is a pattern sequence for geometric shape measurement in which circular patterns of different sizes are arranged in order of size, and can be used for measuring the dot diameter of an image printed on a sheet.

The distance measurement line 450 is formed as a rectangular frame surrounding a plurality of reference patch rows 410 to 440 and a dot diameter measurement pattern row 460. The chart position specifying marker 470 is provided at the positions of the four corners of the distance measurement line 450, and functions as a marker for specifying the position of each reference patch. By specifying the distance measurement line 450 and the chart position specifying markers 470 at the four corners from the image of the reference chart 40 captured by the sensor unit 25, the position of the reference chart 40 and the position of each reference patch or pattern can be specified. can do.

Each reference patch constituting the reference patch rows 410 to 440 for color measurement is used as a reference for color tones reflecting the imaging conditions of the image pickup apparatus 42. The configuration of the reference patch rows 410 to 440 for color measurement arranged on the reference chart 40 is not limited to the example shown in FIG. 7, and any reference patch row can be applied. .. For example, a reference patch that can specify a wide color range as much as possible may be used, and the YMCK primary color reference patch row 410 and the grayscale reference patch row 430 are used in the inkjet recording apparatus 1. It may consist of a patch of color measurement values of the ink. Further, the RGB secondary color reference patch row 420 may be composed of a patch having a color measurement value capable of developing a color with the ink used in the inkjet recording apparatus 1, and further, a color measurement value such as Japan Color may be used. A defined standard color chart may be used.

In the present embodiment, the reference chart 40 having the reference patch rows 410 to 440 in the shape of a general patch (color chart) is used, but the reference chart 40 does not necessarily have such a reference patch row 410 to 440. It does not have to be in the form of. The reference chart 40 may have a configuration in which a plurality of colors that can be used for color measurement are arranged so that their respective positions can be specified.

As described above, the reference chart 40 is arranged on the inner surface side of the bottom plate portion 21a of the housing 21 so as to be adjacent to the opening 23, so that the sensor unit 25 simultaneously captures an image of the subject outside the housing 21. can do. Note that simultaneous imaging here means acquiring image data of one frame including a subject outside the housing 21 and the reference chart 40. That is, even if there is a time lag in data acquisition for each pixel, if the image data in which the subject outside the housing 21 and the reference chart 40 are included in one frame is acquired, the subject outside the housing 21 and the reference chart can be acquired. It means that 40 and 40 were imaged at the same time.

Next, with reference to FIG. 8, a schematic configuration of the control mechanism of the inkjet recording apparatus 1 of the present embodiment will be described. FIG. 8 is a block diagram showing a configuration example of the control mechanism of the inkjet recording device 1.

As shown in FIG. 8, the inkjet recording device 1 of the present embodiment includes a CPU 101, a ROM 102, a RAM 103, a recording head driver 104, a main scanning driver 105, a sub-scanning driver 106, a control FPGA (Field-Programmable Gate Array) 110, and the like. It includes a recording head 16, a gap measuring unit 41, an image pickup device 42, an encoder sensor 130, a main scanning motor 8, and a sub-scanning motor 12. The CPU 101, ROM 102, RAM 103, recording head driver 104, main scan driver 105, sub scan driver 106, and control FPGA 110 are mounted on the main control board 100. The recording head 16, the encoder sensor 130, and the image pickup device 42 are mounted on the carriage 15.

The CPU 101 controls the entire inkjet recording device 1. For example, the CPU 101 uses the RAM 103 as a work area to execute various control programs stored in the ROM 102, and outputs control commands for controlling various operations in the inkjet recording device 1.

The recording head driver 104, the main scanning driver 105, and the sub-scanning driver 106 are drivers for driving the recording head 16, the main scanning motor 8, and the sub-scanning motor 12, respectively.

The control FPGA 110 controls various operations in the inkjet recording device 1 in cooperation with the CPU 101. FIG. 9 is a diagram showing an example of the function of the control FPGA 110. As shown in FIG. 9, the control FPGA 110 includes a CPU control unit 111, a memory control unit 112, a setting unit 120, an ink ejection control unit 113, a sensor control unit 114, and a motor control unit 115. For convenience of explanation, the example of FIG. 9 illustrates only the functions related to the present invention, but the functions of the control FPGA 110 are not limited to these.

The CPU control unit 111 communicates with the CPU 101, conveys various information acquired by the control FPGA 110 to the CPU 101, and inputs a control command output from the CPU 101.

The memory control unit 112 performs memory control for the CPU 101 to access the ROM 102 and the RAM 103.

The setting unit 120 sets the ink ejection performance from the recording head 16 based on the measurement result of the gap measuring unit 41 and the captured image obtained by the imaging by the imaging device 42. The setting of ink ejection performance is a concept including setting of ink ejection timing from the recording head 16 and setting of ink droplet size. In this example, the setting unit 120 includes a first setting unit 121 and a second setting unit 122. The first setting unit 121 sets the ink ejection timing from the recording head 16 based on the measurement result of the gap measuring unit 41. The second setting unit 122 is from the recording head 16 based on the pattern captured image showing the captured image obtained by capturing the pattern image P formed on the sheet after the setting by the first setting unit 121. Reset the ink ejection timing or set the ink droplet size. For example, the pattern image P is an image of a specific color in which the density of each pixel is set to the same value, and the second setting unit 122 is a maximum value and a minimum value of the density of the pattern image P reflected in the pattern captured image. If the difference between the two and the ink is equal to or greater than the threshold value, the timing of ejecting ink from the recording head 16 is reset or the size of the ink droplet is set. More specific contents will be described later. Further, in this example, the setting unit 120 operates in response to a control command from the CPU 101.

The ink ejection control unit 113 controls the operation of the recording head driver 104 in response to a control command from the CPU 101 to control the ink ejection timing from the recording head 16 driven by the recording head driver 104.

The sensor control unit 114 controls various sensors in response to a control command from the CPU 101. For example, the sensor control unit 114 processes a sensor signal such as an encoder value output from the encoder sensor 130. Further, the sensor control unit 114 can also control the gap measurement unit 41 and acquire the measurement result by the gap measurement unit 41. Further, the sensor control unit 114 can also control the image pickup device 42 and acquire the captured image obtained by the image pickup by the image pickup device 42.

The motor control unit 115 controls the operation of the main scanning driver 105 in response to a control command from the CPU 101 to control the main scanning motor 8 driven by the main scanning driver 105 in the main scanning direction of the carriage 15. Control the movement of. Further, the motor control unit 115 controls the operation of the sub-scanning driver 106 in response to a control command from the CPU 101 to control the sub-scanning motor 12 driven by the sub-scanning driver 106, and controls the sub-scanning direction of the sheet. Control the movement to. In this example, the motor control unit 115 can be considered to function as a drive unit for relatively moving the carriage 15 and the seat, or the main scanning motor 8 or the sub-scanning motor 12 can be considered to function as the drive unit. can.

It should be noted that each of the above parts is an example of the control function realized by the control FPGA 110, and various control functions other than these may be configured to be realized by the control FPGA 110. Further, all or a part of the above control functions may be realized by a program executed by the CPU 101 or another general-purpose CPU. Further, a part of the above control function may be realized by dedicated hardware such as another FPGA or ASIC (Application Specific Integrated Circuit) different from the control FPGA 110.

The explanation will be continued by returning to FIG. The recording head 16 is driven by the recording head driver 104 whose operation is controlled by the CPU 101 and the control FPGA 110, and ejects ink to the sheet to form an image.

The encoder sensor 130 outputs the encoder value obtained by detecting the mark on the encoder sheet to the control FPGA 110. This encoder value is sent from the control FPGA 110 to the CPU 101 and is used, for example, to calculate the position and speed of the carriage 15. The CPU 101 generates and outputs a control command for controlling the main scanning motor 8 based on the position and speed of the carriage 15 calculated from the encoder value.

As described above, the gap measuring unit 41 is composed of an optical sensor type displacement meter or the like, and measures the distance between the carriage 15 and the seat. The measurement result by the gap measuring unit 41 is sent to the CPU 101 via the control FPGA 110.

The image pickup device 42 captures the pattern image P formed on the sheet by the sensor unit 25 together with the reference chart 40 when adjusting the ink ejection performance of the inkjet recording device 1, and the image pickup device 42 captures the pattern image P obtained from the captured image. Based on the RGB value and the RGB value of each reference patch of the reference chart 40, the color measurement value of the pattern image P (the color value in the standard color space, for example, L * a * in the L * a * b * color space). b * value) is calculated. The color measurement value of the pattern image P calculated by the image pickup apparatus 42 is sent to the CPU 101 via the control FPGA 110. As a specific method for calculating the colorimetric value of the pattern image P, for example, the method disclosed in Japanese Patent Application Laid-Open No. 2013-051671 can be used.

FIG. 10 is a diagram for explaining a setting method by the first setting unit 121. In the example of FIG. 10, when the ink ejection speed is 10 m / s and the target gap is 1.0 mm, how much the ejection timing is corrected according to the gap measured by the gap measuring unit 41 is shown (). The values in the rightmost column of the table are the correction values). By setting (correcting) the ejection timing in this way, it is possible to control the landing position of the ink on the sheet to the target position even if the gap fluctuates.

FIG. 11 is a diagram for explaining a setting method by the second setting unit 122. The upper image of each of (A) and (B) of FIG. 11 shows the pattern image P (solid image) printed on the sheet. These pattern images P are imaged by the image pickup apparatus 42, and the color between X0 and X1 in the X direction in the drawing is measured. The lower graph is a comparison of the result (image density) with the upper pattern image P. In the graph, the concentration is represented in 256 steps from 0 (light) to 255 (dark). In FIG. 11A, the concentration is always "255", which is a stable quality. Therefore, the setting (additional correction) by the second setting unit 122 is not necessary, and the adjustment ends here. On the other hand, in FIG. 11B, there is a portion where the density is reduced to "230", and it is determined that the setting by the second setting unit 122 is necessary. As described above, the setting method by the second setting unit 122 is carried out by changing (increasing) the size of the ink droplet or correcting the ejection timing again. After the setting by the second setting unit 122 is completed, the image pickup and the color measurement by the image pickup apparatus 42 are performed again, and the above-mentioned determination is performed. The above process is repeated until the quality becomes stable. As the determination at this time, the difference between the maximum value and the minimum value of the image density may be acquired, and the determination may be made based on whether or not the difference is equal to or greater than the threshold value, or the threshold value is exceeded (in the X direction). It may be determined by the combination with the width.

FIG. 12 is a flowchart showing an example of the control of the present embodiment. As shown in FIG. 12, when the adjustment of the ink ejection performance is started, the gap measuring unit 41 measures the gap between the carriage 15 and the seat (step S1). Next, the first setting unit 121 sets the ink ejection timing from the recording head 16 based on the measurement result in step S1 (step S2). Next, the CPU 101 controls the control FPGA 110 so that the pattern image P is formed on the sheet (step S3). Next, the CPU 101 controls the image pickup apparatus 42 and the control FPGA 110 so as to capture the pattern image P formed on the sheet (step S4). In the following description, the captured image obtained by capturing the pattern image P formed on the sheet after the setting in step S2 may be referred to as a “pattern captured image”.

Next, the second setting unit 122 determines whether or not the difference between the maximum value and the minimum value of the density of the pattern image P reflected in the pattern captured image is equal to or greater than the threshold value (step S5). If the result of step S5 is negative (step S5: No), the process ends. On the other hand, when the result of step S5 is affirmative (step S5: Yes), the second setting unit 122 of the ink from the recording head 16 so as to eliminate the difference in image density (difference in the determination target in step S5). Reset the ejection timing or set the size of the ink droplet (step S6). After step S6, the CPU 101 controls the control FPGA 110 so as to form the pattern image P on the sheet again (step S7), and repeats the processes after step S4.

FIG. 13 is a diagram showing an example of the pattern image P. In FIG. 13, the pattern image P has a configuration in which two types of a solid image and a halftone image are mixed as an adjustment pattern. By taking images of these two types of images and acquiring image information, more optimal settings can be performed. For example, even if there is no particular quality problem in a solid image, there may be a case where uneven density occurs because the composition of drops is different in a halftone image. Even in such a case, if this pattern is used, it is determined that the setting by the second setting unit 122 is necessary, and stable quality can be ensured.

As described above, in the present embodiment, from the recording head 16 based on the measurement result (gap between the carriage 15 and the sheet) of the gap measuring unit 41 and the captured image obtained by the imaging by the imaging device 42. Since the ink ejection performance of the above is set, sufficient image quality can be provided as compared with the conventional configuration in which the ink ejection performance is set based only on the gap.

Although the embodiments according to the present invention have been described above, the present invention is not limited to the above-described embodiments as they are, and at the implementation stage, the components can be modified and embodied within a range that does not deviate from the gist thereof. In addition, various inventions can be formed by an appropriate combination of the plurality of components disclosed in the above-described embodiment. For example, some components may be removed from all the components shown in the embodiments.

For example, the image pickup apparatus 42 may have the function of the gap measuring unit 41. In short, the measuring unit (imaging device 42 in this example) that measures the distance (gap) between the carriage 15 and the seat may be in the form of measuring the distance between the carriage 15 and the seat based on the captured image. ..

The function of the image pickup apparatus 42 of this modification will be described with reference to FIG. FIG. 14 is a block diagram showing an example of the function of the image pickup apparatus 42 of the present modification.

As shown in FIG. 14, in addition to the sensor unit 25 and the light source 28 described above, the image pickup apparatus 42 includes a light source drive control unit 51, a timing signal generation unit 52, a frame memory 53, an averaging processing unit 54, and a color measurement calculation unit 56. , Non-volatile memory 57 and distance calculation unit 58. Each of these parts is realized by using, for example, a computer system including a processor and a memory, or dedicated hardware such as FPGA or ASIC. The hardware that realizes the functions of each of these parts is mounted on, for example, a circuit board 24 arranged inside the housing 21 of the image pickup apparatus 42.

The sensor unit 25 converts the light incident through the lens 25b into an electric signal by the two-dimensional image sensor 25a, and outputs the image data of the imaging range illuminated by the light source 28. The sensor unit 25 AD-converts the analog signal obtained by the photoelectric conversion of the two-dimensional image sensor 25a into digital image data, and shading correction, white balance correction, γ correction, and image data format conversion for the image data. It has a built-in function to output after performing various image processing such as. Various operating conditions of the two-dimensional image sensor 25a are set according to various setting signals from the CPU 101. It should be noted that various image processes for the image data may be partially or wholly performed outside the sensor unit 25.

The light source drive control unit 51 generates a light source drive signal for lighting the light source 28 when the sensor unit 25 captures an image, and supplies the light source drive signal to the light source 28.

The timing signal generation unit 52 generates a timing signal for controlling the timing of starting imaging by the sensor unit 25, and supplies the timing signal to the sensor unit 25. In this example, the timing signal generation unit 52 operates under the control of the sensor control unit 114 (CPU101).

The frame memory 53 temporarily stores the image output from the sensor unit 25.

When the averaging processing unit 54 measures the color of the pattern image P, the image area separated by the opening 23 of the housing 21 from the image output from the sensor unit 25 and temporarily stored in the frame memory 53. (Hereinafter, this image area is referred to as a "subject image area") and an image area on which the reference chart 40 is projected (hereinafter, this image area is referred to as a "reference chart image area"). Then, the averaging processing unit 54 averages the image data in a region having a predetermined size in the center of the subject image region, and outputs the obtained value as the RGB value of the pattern image P. Further, the averaging processing unit 54 averages the image data in the area of each reference patch in the reference chart image area, and outputs the obtained value as the RGB value of each reference patch. The RGB value of the pattern image P is passed to the color measurement calculation unit 56. Similar to Japanese Patent Application No. 2016-083877, the RGB value of the pattern image P may be corrected according to the distance calculated by the distance calculation unit 58 and then passed to the color measurement calculation unit 56. In this case, the RGB values of each reference patch on the reference chart 40 are passed to the color measurement calculation unit 56 without being corrected according to the distance calculated by the distance calculation unit 58.

The color measurement calculation unit 56 calculates the color measurement value of the pattern image P based on the RGB value of the pattern image P and the RGB value of each reference patch of the reference chart 40. The color measurement value of the pattern image P calculated by the color measurement calculation unit 56 is sent to the CPU 101 on the main control board 100. Since the color measurement calculation unit 56 can calculate the color measurement value of the pattern image P by, for example, the method disclosed in Japanese Patent Application Laid-Open No. 2013-051671, detailed description of the processing of the color measurement calculation unit 56 is omitted here. do.

The non-volatile memory 57 stores various data and the like necessary for the color measurement calculation unit 56 to calculate the color measurement value of the pattern image P.

The distance calculation unit 58 analyzes an image captured by the sensor unit 25 and temporarily stored in the frame memory 53 to obtain a distance between the housing 21 and a subject outside the housing 21, more specifically, the distance calculation unit 58. The distance (the size of the gap d shown in FIGS. 5 and 6) between the bottom plate portion 21a of the housing 21 and the sheet on which the pattern image P is formed is calculated. Here, the arrangement of the image pickup apparatus 42 is designed so that this interval d corresponds to the gap between the carriage 15 and the seat.

In this example, the light source 28, the sensor unit 25, the light source drive control unit 51, the frame memory 53, and the distance calculation unit 58 have the functions of the gap measurement unit 411 (similar to the above-mentioned gap measurement unit 41). That is, the portion surrounded by the dotted line in FIG. 14 has the function of the gap measuring unit 411. It should be noted that a part of the functions of the gap measuring unit 411 may be mounted on the CPU 101. For example, a part of the processing by the "distance calculation unit 58" may be performed by the CPU 101.

15 to 17 are diagrams showing an example of an image captured by the sensor unit 25. It should be noted that FIGS. 15 to 17 show an example of an image when the sensor unit 25 takes an image of the paper surface of the sheet in which the pattern image P is not formed as a subject.

As shown in FIGS. 15 to 17, the image Im captured by the sensor unit 25 includes a reference chart image area RC, which is an image area reflecting the reference chart 40 inside the housing 21, and an opening portion of the housing 21. An image region in which a subject outside the housing 21 is projected via the housing 21, that is, a subject image region RO which is an image region separated by an opening 23 of the housing 21 is included. The subject image region RO is the outside of the high-luminance region RO_h showing high luminance (the outside of the direction orthogonal to the direction in which the reference chart 40 and the opening 23 are arranged, and in the examples of FIGS. 15 to 17, the high-luminance region RO. In the image above and below RO_h, a low-luminance region RO_l showing low luminance appears in a band shape.

In the image Im captured by the sensor unit 25, the low-luminance region RO_l appears outside the high-luminance region RO_h of the subject image region RO at the positions of the sensor unit 25 and the light source 28 with respect to the opening 23 of the housing 21. This is because, due to the difference in the relationship, a region where the light from one of the two light sources 28 is not irradiated is generated in the outer portion of the image pickup range of the subject outside the housing 21 imaged by the sensor unit 25. Here, since the sensor unit 25 and the light source 28 are fixedly provided in the housing 21 having the opening 23, the size of the subject image region RO in the image Im captured by the sensor unit 25 does not change. However, the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h of the subject image region RO varies depending on the distance between the housing 21 and the subject outside the housing 21.

The image Im shown in FIG. 16 is an example of an image captured by the sensor unit 25 in a state where the distance between the housing 21 and the subject (paper surface of the sheet) outside the housing 21 is smaller than the image Im shown in FIG. Is shown. As can be seen by comparing the image Im shown in FIG. 15 with the image Im shown in FIG. 16, when the distance between the housing 21 and the subject outside the housing 21 becomes smaller, the high-luminance region RO_h of the subject image region RO becomes The ratio of the size of the low-luminance region RO_l to the size becomes small.

The image Im shown in FIG. 17 is an example of an image captured by the sensor unit 25 in a state where the distance between the housing 21 and the subject (paper surface of the sheet) outside the housing 21 is larger than the image Im shown in FIG. Is shown. As can be seen by comparing the image Im shown in FIG. 17 with the image Im shown in FIG. 15, when the distance between the housing 21 and the subject outside the housing 21 becomes large, the high-luminance region RO_h of the subject image region RO becomes large. The ratio of the size of the low-luminance region RO_l to the size increases.

As described above, in the image Im captured by the sensor unit 25, the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h of the subject image region RO is the ratio between the housing 21 and the subject outside the housing 21. It is a value that depends on the distance between and. Therefore, the distance between the housing 21 and the subject outside the housing 21 can be calculated by obtaining the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h of the subject image region RO. ..

The distance calculation unit 58 calculates the distance between the housing 21 and the subject outside the housing 21 by, for example, the following method. That is, the distance calculation unit 58 first extracts the subject image area RO from the image Im imaged by the sensor unit 25 and temporarily stored in the frame memory 53. Then, for example, the distance calculation unit 58 performs binarization processing using a predetermined threshold value on the extracted subject image region RO, and sets the high-luminance region RO_h in the subject image region RO as white pixels and the low-luminance region. A binarized image with RO_l as a black pixel is generated.

Next, the distance calculation unit 58 determines the number of white pixels and the number of black pixels in the direction orthogonal to the direction in which the reference chart image area RC and the subject image area RO are arranged in the image Im with respect to the generated binarized image. The number is counted, and the ratio of the number of pixels of the black pixel to the number of pixels of the white pixel is calculated as the ratio of the size of the low brightness region RO_l to the size of the high brightness region RO_h. In the image pickup apparatus 42 of the present embodiment, as described above, the two light sources 28 are evenly distributed in the direction orthogonal to the direction in which the opening 23 and the reference chart 40 are arranged with respect to the center of the lens 25b of the sensor unit 25. It is placed in. Therefore, there is no relative inclination between the housing 21 and the subject, more specifically, the bottom plate portion 21a of the housing 21 and the paper surface of the sheet on which the pattern image P is formed are parallel to each other. Assuming that it is maintained, the low-brightness region RO_l in the subject image region RO is on both sides of the high-brightness region RO_h in the direction orthogonal to the direction in which the reference chart image region RC and the subject image region RO are aligned in the image Im. Appears in even size. Therefore, the number of white pixels and the number of black pixels need to be counted only in the half size of the subject image region RO, that is, in the direction from the center of the subject image region RO toward one low-luminance region RO_l. ..

The distance calculation unit 58 calculates the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h of the subject image region RO as described above, and based on the obtained ratio, the housing 21 and the housing. 21 Calculate the distance to an external subject. The method of calculating the distance between the housing 21 and the subject outside the housing 21 from the ratio of the size of the low-brightness region RO_l to the size of the high-brightness region RO_h is the method for calculating the distance between the housing 21 and the opening 23 of the housing 21. There are three possible ways depending on the positional relationship of the light source 28. Hereinafter, these three calculation methods will be described individually.

<Distance calculation method 1>
FIG. 18 is a diagram illustrating a method of calculating the distance between the housing 21 and the subject outside the housing 21 from the ratio of the size of the low-luminance region RO_l to the size of the high-brightness region RO_h, and is a light source. This is an example of the case where 28 is mounted on the circuit board 24 so as to be located directly above the edge portion of the opening 23.

As shown in FIG. 18, the position of the light source 28 is M, the center position of the lens 25b of the sensor unit 25 is A, the lower edge position of the opening 23 is B, and the intersection of the extension line of the line segment AB and the subject is C. D, a line segment at the intersection of a straight line perpendicular to the subject from the center position A of the lens 25b (optical axis of the sensor unit 25) and a straight line parallel to the subject passing through the lower edge position B of the opening 23. Let E be the intersection of the extension line of the minute AD and the subject, and let F be the intersection of the straight line passing through the lower edge position B of the opening 23 from the position M of the light source 28 and the subject. At this time, assuming that the length of the line segment AD is L1 and the length of the line segment DE is L2, L2 is the distance between the housing 21 and the subject, which is the desired length. Further, assuming that the length of the line segment CF is X and the length of the line segment FE is Y, X / Y corresponds to the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h.

As can be seen from FIG. 18, even if the value of L2, which is the distance between the housing 21 and the subject, changes, the value of Y does not change, and the value is equal to the length of the line segment BD. On the other hand, the value of X becomes smaller as the value of L2 becomes smaller, and becomes larger as the value of L2 becomes larger. Therefore, if X / Y, which is the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h, is known, the value of L2, which is the distance between the housing 21 and the subject, can be known.

In FIG. 18, since the right triangle BCF and the right triangle ABD have similar figures, X: L2 = Y: L1. Therefore, X · L1 = L2 · Y, and when this is modified, X / Y = L2 / L1. Here, since the value of L1 is a fixed value determined by the mounting position of the sensor unit 25, if X / Y, which is the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h, is known, the housing 21 The value of L2, which is the distance between the subject and the subject, can be found.

<Distance calculation method 2>
FIG. 19 is a diagram illustrating a method of calculating the distance between the housing 21 and the subject outside the housing 21 from the ratio of the size of the low-luminance region RO_l to the size of the high-brightness region RO_h, and is a light source. This is an example of the case where the 28 is mounted on the circuit board 24 so as to be located closer to the lens 25b of the sensor unit 25 than directly above the edge portion of the opening 23.

As shown in FIG. 19, the position of the light source 28 is M, the center position of the lens 25b of the sensor unit 25 is A, the lower edge position of the opening 23 is B, and the intersection of the extension line of the line line AB and the subject is C. D, a line at the intersection of a straight line perpendicular to the subject from the center position A of the lens 25b (optical axis of the sensor unit 25) and a straight line parallel to the subject passing through the lower edge position B of the opening 23. The intersection of the extension line of the minute AD and the subject is E, the intersection of the straight line perpendicular to the subject from the lower edge position B of the opening 23 and the subject is F, and the lower edge of the opening 23 from the light source 28. The intersection of the straight line passing through the position B and the subject is G, the intersection of the straight line and the line BD perpendicular to the line BD from the position M of the light source 28 is I, and the extension of the line MI and the line FE. Let J be the intersection with J, and let K be the intersection of the straight line passing through the center position A of the lens 25b and parallel to the line BD and the extension line of the line IM. At this time, assuming that the length of the line segment AD is L1, the length of the line segment DE is L2, and the length of the line segment KM is L3, L2 is the distance between the housing 21 and the subject, and the desired length is obtained. It becomes. Further, assuming that the length of the line segment CG is X'and the length of the line segment GE is Y', X'/ Y'corresponds to the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h. do.

As can be seen from FIG. 19, when the value of L2, which is the distance between the housing 21 and the subject, is 0, the value of X'is 0, and the value of Y'is equal to the length of the line segment BD. It becomes Y. Then, as the value of L2 increases, the value of X'increases at a predetermined ratio, and the value of Y'also increases at a predetermined ratio. Therefore, if X'/ Y', which is the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h, is known, the value of L2, which is the distance between the housing 21 and the subject, can be known.

In FIG. 19, the length of the line segment GF is set to k. At this time, since the right triangle BCF and the right triangle ABD have similar figures, (X'+ k): L2 = Y: L1. Therefore, it can be expressed as X'= (Y · L2 / L1) −k. Further, Y'= Y + k.

Here, I want to find the value of k. Let the length of the line segment BI be m. At this time, since the right triangle MBI and the right triangle BGF have similar figures, m: L1-L3 = k: L2. Therefore, it can be expressed as k = L2 · m / (L1-L3). Here, m / (L1-L3) is a constant uniquely determined by the layout. If this m / (L1-L3) is α, it can be expressed as k = α · L2.

Therefore, X'= (Y · L2 / L1) −α · L2 and Y ′ = Y + α · L2. Further, by transforming X'= (Y · L2 / L1) −α · L2, it can be expressed as X ′ = L2 ((Y / L1) −α). Here, since Y / L1 is also a constant uniquely determined by the layout, if Y / L1 is β, it can be expressed as X'= L2 (β-α).

From the above, X'/ Y'= L2 (β-α) / Y + α · L2. Since α = m / (L1-L3) and β = Y / L1 are constants uniquely determined by the layout as described above, the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h. If X'/ Y'is known, the value of L2, which is the distance between the housing 21 and the subject, can be known.

<Distance calculation method 3>
FIG. 20 is a diagram illustrating a method of calculating the distance between the housing 21 and the subject outside the housing 21 from the ratio of the size of the low-luminance region RO_l to the size of the high-brightness region RO_h, and is a light source. This is an example of the case where the 28 is mounted on the circuit board 24 so as to be located closer to the side wall portion 21c than directly above the edge portion of the opening 23.

As shown in FIG. 20, the position of the light source 28 is M, the center position of the lens 25b of the sensor unit 25 is A, the lower edge position of the opening 23 is B, the upper edge position of the opening 23 is H, and the line segment AB. C, a straight line perpendicular to the subject from the center position A of the lens 25b (optical axis of the sensor unit 25), and the subject passing through the lower edge position B of the opening 23. The intersection of the parallel straight lines is D, the intersection of the extension of the line AD and the subject is E, and the intersection of the straight line perpendicular to the subject from the lower edge position B of the opening 23 is F. The intersection of the straight line passing through the upper edge position H of the opening 23 from the position M of the light source 28 and the subject is G', and the intersection of the line HG'and the line BD is lowered from I and I perpendicularly to the subject. The intersection of the straight line and the subject is J, the intersection of the straight line and the bottom plate 21a perpendicular to the bottom plate 21a of the housing 21 from the position M of the light source 28 is O, and the line passes through the center position A of the lens 25b. Let K be the intersection of a straight line parallel to the minute BD and an extension of the line OM. At this time, assuming that the length of the line segment AD is L1 and the length of the line segment DE is L2, L2 is the distance between the housing 21 and the subject, which is the desired length. Further, if the length of the line segment BI is x, the length of the line segment ID is y, the length of the line segment CG'is X'', and the length of the line segment G'E is Y'', then X' '/ Y'' corresponds to the ratio of the size of the low brightness region RO_l to the size of the high brightness region RO_h.

As can be seen from FIG. 20, when the value of L2, which is the distance between the housing 21 and the subject, is 0, the value of X ″ is x and the value of Y ″ is y. Then, as the value of L2 increases, the value of X ″ increases from x at a predetermined ratio, and the value of Y ″ decreases at a predetermined ratio from y. Therefore, if X ″ / Y ″, which is the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h, is known, the value of L2, which is the distance between the housing 21 and the subject, can be known.

First, I would like to find the size of x. In FIG. 20, the length of the line segment HB (thickness of the bottom plate portion 21a) is a, the length of the line segment MO is b, and the length of the line segment OH is c. At this time, since the right triangle MOH and the right triangle HBI have similar figures, L1-L3-a: a = c: x. Therefore, it can be expressed as x = a · c / (L1-L3-a). Here, when L2 = 0, X'' = x and Y'' = y, so if the length of the line segment BD is d, then X'' / Y''= x / y = {a. -C / (L1-L3-a)} / {d-a · c / (L1-L3-a)}. Here, since the values of L1, L3, a, b, c, and d are all values determined by the layout, {a · c / (L1-L3-a)} / {d-a · c / (L1). -L3-a)} is a fixed value. Therefore, if X ″ / Y ″, which is the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h, is this value, it can be seen that L2 = 0.

Next, I would like to obtain the size of the line segment CF and the size of the line segment FG'. In FIG. 20, the length of the line segment CF is e, and the length of the line segment FG'is f. At this time, since the right triangle ABD and the right triangle BCF have similar figures, L1: d = L2: e. Therefore, it can be expressed as e = d · L2 / L1. Further, since the right triangle HBI and the right triangle IJG'are similar figures, a: x = L2: fx. Therefore, it can be expressed as f = x · (a + L2) / a.

Here, since CG'= CF + FG', it can be expressed as X ″ = d · L2 / L1 + x · (a + L2) / a = L2 · (d / L1 + x / a) + x. Here, d / L1 + x / a is a constant uniquely determined by the layout. If this d / L1 + x / a is α, it can be expressed as X ″ = L2 · α + x.

Further, when the value of X ″ + Y ″ is obtained, since the right triangle ABD and the right triangle ACE have similar figures, d: L1 = (X ″ + Y ″) :( L1 + L2). Therefore, it can be expressed as X ″ + Y ″ = d · (L1 + L2) / L1 = L2 · d / L1 + d. Here, d / L1 is a constant uniquely determined by the layout. If this d / L1 is β, it can be expressed as X ″ + Y ″ = L2 · β + d. Therefore, it can be expressed as Y ″ = L2 · β + d−X ″ = L2 · β + d− (L2 · α + x).

From the above, X ″ / Y ″ = (L2 ・ α + x) / {L2 ・ β + d− (L2 ・ α + x)}. Here, α = d / L1 + x / a and β = d / L1 are constants uniquely determined by the layout, respectively, as described above. Further, both the value of x and the value of d are values uniquely determined by the layout. Therefore, if X ″ / Y ″, which is the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h, is known, the value of L2, which is the distance between the housing 21 and the subject, can be known.

<Other methods>
In the above description, the distance between the housing 21 and the subject outside the housing 21 is calculated based on the ratio of the size of the low-luminance region RO_l to the size of the high-luminance region RO_h of the subject image region RO. It is supposed to be done. However, the size of the low-luminance region RO_l and the size of the high-luminance region RO_h (only the size of the low-luminance region RO_l in the example of FIG. 18) depend on the distance between the housing 21 and the subject, as described above. It changes linearly. Therefore, a correspondence table showing the correspondence relationship between the size of the low-luminance region RO_l or the high-luminance region RO_h and the distance between the housing 21 and the subject is prepared in advance, and the housing 21 is used using this correspondence table. The distance between the subject and the subject may be calculated.

In this case, in the above-mentioned correspondence table, the image is taken by the sensor unit 25 while sequentially changing the distance between the housing 21 and the subject, and the obtained image is analyzed and acquired in the low-luminance region RO_l or the high-luminance region. It is created by associating the size of RO_h with the distance between the housing 21 and the subject when the image is captured, and is stored in a non-volatile memory 57 (an example of a first table holding unit) or the like. Then, the distance calculation unit 58 analyzes the image captured by the sensor unit 25 when calculating the distance between the housing 21 and the subject, and acquires the size of the low-luminance region RO_l or the high-luminance region RO_h. Then, with reference to the corresponding table held by the non-volatile memory 57, the distance between the housing 21 and the subject corresponding to the acquired size of the low-luminance region RO_l or the high-luminance region RO_h is calculated.

The distance between the housing 21 and the subject calculated by the distance calculation unit 58 (corresponding to the gap between the carriage 15 and the seat in this example) is passed to the CPU 101 and is passed to the CPU 101 to be the first setting unit 121 described above. Will be used for setting by.

<Operation>
Next, the distance measurement operation by the image pickup apparatus 42 of this modification will be briefly described. FIG. 21 is a flowchart showing a procedure of distance measurement by the image pickup apparatus 42 of this modified example.

When measuring the distance between the housing 21 and the subject outside the housing 21, the image pickup device 42 of this modification first turns on the light source 28 by the light source drive control unit 51 (step S101). Then, with the light source 28 lit, image pickup is performed by the sensor unit 25 (step S102). The image Im imaged by the sensor unit 25 and output from the sensor unit 25 is stored in the frame memory 53.

Next, the distance calculation unit 58 extracts the subject image area RO from the image Im captured by the sensor unit 25 and stored in the frame memory 53 (step S103). Then, the distance calculation unit 58 performs, for example, binarization processing for the extracted subject image region RO, processing for counting the number of pixels of black pixels and white pixels, and the like, and low-luminance region RO_l with respect to the size of the high-luminance region RO_h. The ratio of the sizes of is calculated (step S104). Then, the distance calculation unit 58 calculates the distance between the housing 21 and the subject based on the calculated ratio (step S105), and passes the calculated distance to the CPU 101. As a result, the distance measurement operation by the image pickup apparatus 42 of this modification is completed.

<Ink (liquid)>
Next, the ink (liquid) used in the inkjet recording apparatus 1 according to the embodiment will be described. The ink used for the inkjet recording apparatus 1 according to the embodiment can be used without particular limitation. In particular, when an ink containing water, an organic solvent, a coloring material, a surfactant and resin particles is used, the solid wettability is good, so that image density unevenness can be effectively suppressed.

<Water>
The content of water in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but from the viewpoint of ink drying property and ejection reliability, it is preferably 10% by mass or more and 90% by mass or less, and 20% by mass. % To 60% by mass is more preferable.

<Organic solvent>
The organic solvent is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds.

Specific examples of the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-Pentanediol, 1,5-Pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Polyhydric alcohols such as 1,3-pentanediol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl Polyhydric alcohol alkyl ethers such as ethers, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone. , 1,3-Dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone and other nitrogen-containing heterocyclic compounds, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N- Amidos such as dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate, carbonic acid. Examples include ethylene.

As the water-soluble organic solvent, it is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because it not only functions as a wetting agent but also has good drying properties. As a specific example of the water-soluble organic solvent, a polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.

Specific examples of the glycol ether compound include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers; Examples thereof include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve the permeability of ink when paper is used as a recording medium.

The content of the organic solvent in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass or more and 60% by mass or less from the viewpoint of ink drying property and ejection reliability. More preferably, it is 20% by mass or more and 60% by mass or less.

<Color material>
The coloring material is not particularly limited, and pigments and dyes can be used.

As the pigment, an inorganic pigment or an organic pigment can be used. These may be used alone or in combination of two or more. Further, a mixed crystal may be used.

As the pigment, for example, black pigment, yellow pigment, magenta pigment, cyan pigment, white pigment, green pigment, orange pigment, glossy color pigment such as gold or silver, metallic pigment and the like can be used.

Inorganic pigments include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, as well as carbon produced by known methods such as the contact method, furnace method, and thermal method. Black can be used.

Examples of organic pigments include azo pigments and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.). , Dye chelate (for example, basic dye type chelate, acid dye type chelate, etc.), nitro pigment, nitroso pigment, aniline black and the like can be used. Among these pigments, those having a good affinity with a solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.

Specific examples of the pigment for black include carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, or copper and iron (CI pigment black 11). Examples thereof include metals such as titanium oxide and organic pigments such as aniline black (CI pigment black 1).

Further, as a specific example of the pigment for color, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 1, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmin 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Mengara), 104, 105, 106, 108 ( Cadmium Red), 112, 114, 122 (Quinacridone Magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment Violet 1 (Rhodamine Lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15: 1, 15: 2, 15: 3, 15: 4 (phthalocyanine blue), 16, 17: 1, 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, and the like.

The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used, and one type may be used alone or two or more types may be used in combination.

Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9, 45, 249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. I. Direct Red 1, 4, 9, 80, 81, 225, 227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Direct Black 19, 38, 51, 71, 154, 168, 171 and 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive Blacks 3, 4, and 35 can be mentioned.

The content of the coloring material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass, from the viewpoint of improving the image density, good fixing property and ejection stability. It is as follows.

In order to disperse the pigment to obtain an ink, a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersing pigment, a method of coating the surface of the pigment with a resin and dispersing it, and a method of dispersing using a dispersant are used. The method, etc. can be mentioned.

As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment, for example, a method of adding a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon) so that the pigment can be dispersed in water. Can be mentioned.

Examples of the method of coating the surface of the pigment with a resin and dispersing the pigment include a method of encapsulating the pigment in microcapsules so that the pigment can be dispersed in water. This can be rephrased as a resin-coated pigment. In this case, it is not necessary that all the pigments blended in the ink are coated with the resin, and the uncoated pigments and the partially coated pigments are dispersed in the ink as long as the effect of the present invention is not impaired. May be.

Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular-weight dispersant and high-molecular-weight dispersant represented by a surfactant.

As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant and the like can be used depending on the pigment.

As the dispersant, RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fat Co., Ltd. and a naphthalene sulfonic acid Na formalin condensate can also be preferably used. The dispersant may be used alone or in combination of two or more.

<Pigment dispersion>
It is possible to obtain an ink by mixing a material such as water or an organic solvent with a pigment. It is also possible to produce an ink by mixing a material such as water or an organic solvent with a pigment dispersion obtained by mixing a pigment and other water or a dispersant.

The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. It is good to use a disperser for dispersion.

The particle size of the pigment in the pigment dispersion is not particularly limited, but the maximum frequency is 20 nm or more in terms of the maximum number because the dispersion stability of the pigment is good and the image quality such as ejection stability and image density is also high. It is preferably 500 nm or less, and more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the intended purpose, but is 0.1% by mass from the viewpoint of obtaining good ejection stability and increasing the image density. 50% by mass or more is preferable, and 0.1% by mass or more and 30% by mass or less is more preferable.

It is preferable that the pigment dispersion is degassed by filtering coarse particles with a filter, a centrifuge, or the like, if necessary.

<Surfactant>
The surfactant is not particularly limited, but a siloxane compound is preferable from the viewpoint of solid wettability. Further, as the surfactant, the total amount of the surfactant added in the ink is preferably 10% by mass or less from the viewpoint of fixability. By adding the siloxane compound to the ink, the affinity between various recording media and the ink is improved, and the ink spreads immediately after adhering to the recording medium and expands the surface area. As a result, the solid wettability of the ink to the recording medium becomes good, and a high-quality image can be obtained.

<siloxane compound>
The siloxane compound is generally a side chain of a compound having a polysiloxane portion (silicone-based compound) such as polydimethylsiloxane, and / or a compound having a hydrophilic group or a hydrophilic polymer chain at the terminal. Examples of hydrophilic groups and hydrophilic polymer chains include polyether bonds (polyethylene oxide, polypropylene oxide and copolymers thereof, etc.), polyglycerin (C3Η6O (CH2CH (OH) CH2O) n-H, etc.), pyrrolidone, and the like. Betain (C3Η6N + Me2-CH2COO-, etc.), sulfate (C3H6O (C2H4O) n-SO3Na, etc.), phosphate (C3Η6O (C2H4O) n-P (= O) OHONa, etc.), quaternary salt (C3H6N + Me3Cl-, etc.) Can be mentioned. In the above chemical formula, n represents an integer of 1 or more.

Further, as the siloxane compound, other monomers copolymerizable with polydimethylsiloxane having a polymerizable vinyl group at the terminal (at least a part of the monomer is a hydrophilic monomer such as (meth) acrylic acid or a salt thereof). A vinyl-based copolymer having a silicone-based compound chain such as polydimethylsiloxane in the side chain obtained by copolymerization with (preferably used) can also be mentioned.

Among these, as the siloxane compound, a compound having a hydrophilic polymer chain in a compound having a polysiloxane portion is preferable. As the hydrophilic polymer chain, one containing a polyether bond is particularly preferable.

Further, the siloxane compound is particularly preferably a nonionic surfactant having a structure of methylpolysiloxane as a hydrophobic group and polyoxyethylene as a hydrophilic group.

The HLB of the above siloxane compound is preferably 8.0 or less. When the HLB is 8.0 or less, excellent ink drying property can be ensured at the time of inkjet printing on various impermeable recording media.

Here, the HLB (hydrophilic / hydrophobic group balance "Hydrophile-Lipophile Balance") is defined by the following formula (Griffin method).
HLB = 20 × (total formula weight of hydrophilic part / molecular weight)

Suitable siloxane compounds include Silface SAG005 (manufactured by Nisshin Chemical Industry Co., Ltd .; HLB = 7.0) and Silface SAG008 (manufactured by Nisshin Chemical Industry Co., Ltd .; HLB = 7.0). , Silface SAG002 (manufactured by Shin-Etsu Chemical Co., Ltd .; HLB = 12.0), FZ2110 (manufactured by Toray Dow Co., Ltd .; HLB = 1.0), FZ2166 (manufactured by Toray Dow Co., Ltd.) HLB = 5.8), SH-3772M (manufactured by Toray Dow Co., Ltd., HLB = 6.0), L7001 (manufactured by Toray Dow Co., Ltd .; HLB = 7.4), SH-3773M ( Toray Dow Co., Ltd .; HLB = 8.0), KF-945 (Shin-Etsu Chemical Co., Ltd .; HLB = 4.0), KF-6017 (Shin-Etsu Chemical Co., Ltd .; HLB) = 4.5), FormBan MS-575 (manufactured by Ultra Addives Inc.; HLB = 5.0) and the like.

The above-mentioned siloxane compound may be used alone or in combination of two or more. The total amount of the above siloxane compound in the ink is preferably 0.4% by mass to 4.0% by mass, more preferably 1.0% by mass to 2.0% by mass. When the content is 1.0% by mass to 2.0% by mass, ink fixability to various impermeable recording media can be ensured, and image quality such as gloss is also good.

<Resin particles>
The resin particles are not particularly limited, but for example, polyester resin particles; polyurethane resin particles; epoxy resin particles; polyamide resin particles; polyether resin particles; acrylic resin particles; acrylic-silicone resin particles; condensation of fluororesins and the like. Synthetic resin particles; Additive synthetic resin particles such as polyolefin resin particles, polystyrene resin particles, polyvinyl alcohol resin particles, polyvinyl ester resin particles, unsaturated carboxylic acid resin, etc .; celluloses, rosins, natural rubbers, etc. Examples include natural polymers. Among these resin particles, polyurethane resin particles are preferable from the viewpoint of ink fixability to a non-permeable recording medium. The polyurethane resin particles have good dispersibility compatibility with the siloxane compound, and since the film-forming property is enhanced, good drying properties can be obtained, and color bleeding can be effectively suppressed.

<Additives>
If necessary, an antifoaming agent, an antiseptic / antifungal agent, a rust preventive agent, a pH adjuster and the like may be added to the ink.

[Example]
<Ink preparation>
Hereinafter, the present invention will be described in more detail with reference to some examples of ink preparation, but the present invention is not limited to these examples. In the example, "part" is "part by mass", and "%" is "% by mass" except for those in the evaluation criteria.

<Preparation of pigment dispersion>
<Preparation example of black pigment dispersion liquid>
After premixing the following formulation mixture, circulate and disperse the black pigment dispersion for 7 hours with a disc-type bead mill (manufactured by Simmal Enterprises Co., Ltd .: KDL type, media: using zirconia balls with a diameter of 0.3 mm). Obtained.
Carbon black pigment (trade name: Monarch800, manufactured by Cabot Corporation), 15 parts Anionic surfactant (Pionin A-51-B, manufactured by Takemoto Oil & Fat Co., Ltd.) ... 2 parts Ion-exchanged water ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 83 copies

<Preparation example of cyan pigment dispersion liquid>
The carbon black pigment was added to C.I. I. A cyan pigment dispersion was obtained in the same manner as in Preparation Example 1 of the black pigment dispersion except that the pigment blue was changed to Pigment Blue 15: 3 (trade name: LIONOL BLUE FG-7351, manufactured by Toyo Ink Co., Ltd.).

<Preparation example of magenta pigment dispersion liquid>
The carbon black pigment was added to C.I. I. A magenta pigment dispersion was obtained in the same manner as in Preparation Example 1 of the black pigment dispersion except that it was changed to Pigment Red 122 (trade name: Toner Magenta EO02, manufactured by Clariant Japan Co., Ltd.).

<Preparation example of yellow pigment dispersion liquid>
The carbon black pigment was added to C.I. I. A yellow pigment dispersion was obtained in the same manner as in Preparation Example 1 of the black pigment dispersion except that it was changed to Pigment Yellow 74 (trade name: First Yellow 531 and manufactured by Dainichi Seika Kogyo Co., Ltd.).

(Example 1)
<Preparation of ink for Example 1>
Black pigment dispersion 20%, Megafuck F-470 (fluorosurfactant, manufactured by Dainippon Ink and Chemicals Co., Ltd.) 0.4%, 3-methoxy-N, N-dimethylpropionamide (trade name:) Equamid M-100, manufactured by Idemitsu Kosan Co., Ltd.) 15%, 1,2-propanediol 4%, 1,3-butanediol 4%, dipropylene glycol monomethyl ether 15%, trade name as preservative: Proxel LV Ink 1 was prepared by mixing and stirring 0.1% (manufactured by Abyssia Co., Ltd.) and high pure water and filtering with a 0.2 μm polypropylene filter.

(Examples 2 to 6)
In Examples 2 to 6, inks were prepared in the same manner as in Example 1 except that the composition and content of the inks shown in Table 1 were changed.

<Image formation method>
Using the pattern image shown in FIG. 13, the image was formed according to the control shown in the flowchart of FIG. 12 in the inkjet recording apparatus 1 shown in FIG.

<Evaluation method>
(1) Solid wettability The solid part of the obtained image was observed at 20 times using a microscope (VHX-200 manufactured by KEYENCE CORPORATION), and the ink excluding the area where the ink did not adhere in the observed image. The adhesion area was measured and evaluated according to the following criteria.
⊚: Ink adhesion area 100%
◯: Ink adhesion area 98% or more and less than 100% Δ: Ink adhesion area 95% or more and less than 98% ×: Ink adhesion area less than 95%

(2) Image density unevenness For the solid part of the obtained image, a grid is created so that the vertical and horizontal directions are divided into four equal parts, and the density of the intersections of the nine grids is measured by a colorimeter (X-Rite eXact manufactured by X-Rite). ), And evaluated according to the following criteria.
⊚: The difference between the largest concentration and the smallest concentration is less than 0.1 ○: The difference between the largest concentration and the smallest concentration is 0.1 or more and less than 0.15 △: The largest concentration and the most The difference between the small concentrations is 0.15 or more and less than 0.2. ×: The difference between the largest concentration and the smallest concentration is 0.2 or more.

(3) Fixability For the solid part of the obtained image, the number of remaining cells of 100 test cells is counted by a grid peeling test using a cloth adhesive tape (123LW-50 manufactured by Nichiban Co., Ltd.). It was evaluated by.
⊚: Number of remaining cells is 98 or more ○: Number of remaining cells is 90 or more and less than 98 Δ: Number of remaining cells is 70 or more and less than 90 ×: Number of remaining cells is less than 70

1 Inkjet recording device 2 Image forming unit 3 Sheet transport unit 8 Main scanning motor 12 Sub-scanning motor 15 Carriage 16 Recording head 25 Sensor unit 28 Light source 41 Gap measurement unit 42 Image pickup device 51 Light source drive control unit 52 Timing signal generation unit 53 Frame memory 54 Average processing unit 56 Color measurement unit 57 Non-volatile memory 58 Distance calculation unit 101 CPU
102 ROM
103 RAM
104 Recording head driver 105 Main scan driver 106 Sub scan driver 110 Control FPGA
111 CPU control unit 112 Memory control unit 113 Ink ejection control unit 114 Sensor control unit 115 Motor control unit 120 Setting unit 121 First setting unit 122 Second setting unit 130 Encoder sensor

Japanese Unexamined Patent Publication No. 2014-004751

Claims (8)

A carriage equipped with a head that discharges liquid to the object to be discharged,
A drive unit that relatively moves the carriage and the ejected object,
A measuring unit that measures the distance between the carriage and the ejected object,
An image pickup unit that captures an image of the ejected object, and
A setting unit for setting the discharge performance of the liquid from the head based on the measurement result of the measurement unit and the image captured by the image pickup by the image pickup unit is provided .
The setting unit is
A first setting unit that sets the discharge timing of the liquid from the head based on the measurement result of the measurement unit, and
The timing of discharging the liquid from the head is based on the pattern captured image showing the captured image obtained by imaging the pattern image formed on the ejected object after the setting by the first setting unit. Including a second setting unit for resetting or setting the size of the droplet,
A device that discharges liquid. The measuring unit measures the distance between the carriage and the ejected object based on the captured image.
The device for discharging the liquid according to claim 1. The pattern image is an image of a specific color in which the density of each pixel is set to the same value.
When the difference between the maximum value and the minimum value of the density of the pattern image reflected in the pattern captured image is equal to or more than the threshold value, the second setting unit resets the timing of discharging the liquid from the head. Or, set the size of the droplet,
The device for discharging the liquid according to claim 1 . The liquid is ink
The ink contains water, an organic solvent, a coloring material, a surfactant and resin particles.
The device for discharging the liquid according to any one of claims 1 to 3 . The surfactant is a siloxane compound,
The device for discharging the liquid according to claim 4 . The HLB value of the siloxane compound is 8.0 or less, and is
The total amount of the siloxane compound added is 0.4% by mass or more in the ink.
The device for discharging the liquid according to claim 5 . The resin particles are urethane resins.
The device for discharging the liquid according to any one of claims 4 to 6 . A carriage equipped with a head that discharges liquid to the object to be discharged,
A drive unit that relatively moves the carriage and the ejected object,
A measuring unit that measures the distance between the carriage and the ejected object,
An image pickup unit that captures an image of the ejected object, and
A setting unit that sets the discharge performance of the liquid from the head based on the measurement result of the measurement unit and the image captured by the image pickup by the image pickup unit.
It is a liquid discharge method in a device for discharging a liquid provided with the above.
As the liquid, an ink containing water, an organic solvent, a coloring material, a surfactant and resin particles was used .
In the setting section,
A first setting step of setting the discharge timing of the liquid from the head based on the measurement result of the measurement unit, and
The timing of ejection of the liquid from the head is based on the pattern captured image showing the captured image obtained by imaging the pattern image formed on the ejected object after the setting by the first setting step. A second setting step of resetting or setting the size of the droplet, and the like.
Liquid discharge method.

Images