JPWO2017169507A1 - Image reading apparatus, image recording apparatus, and control method of image reading apparatus - Google Patents

Abstract

Provided are an image reading apparatus, an image recording apparatus, and an image reading apparatus control method capable of generating imaging data of a more appropriate reference member. The image reading apparatus includes: a reading unit that detects reflected light on the surface of the reading target using an image sensor; and a reading control unit that causes the reading unit to perform a recording medium reading operation and a reference member reading operation; Imaging data generating means for generating reference member imaging data used for calibration of the means, and moving means for performing a moving operation for moving at least one of the reading means and the reference member in the direction of the incident axis of light to the imaging element. In the reading control means, in the reference member reading operation, the distance in the incident axis direction between the surface of the reference member and the light incident surface of the reading means is preset as the distance when the recording medium reading operation is performed. The moving operation is performed so as to be the standard distance, and the reference member at the position where the distance from the light incident surface is the standard distance is read by the reading unit.

Description

  The present invention relates to an image reading apparatus, an image recording apparatus, and a control method for the image reading apparatus.

  2. Description of the Related Art Conventionally, an image reading apparatus that emits light from a light source to a recording medium on which an image is recorded, reads an image on the recording medium by a reading unit such as a line sensor in which a plurality of imaging elements are arranged, and generates imaging data. is there. In such an image reading apparatus, the reading unit is calibrated in order to correct variations in sensitivity of the image pickup elements and uneven illuminance on the recording medium due to the light source. In the calibration of the reading means, a reference member such as a white plate whose reflectance is uniform and known is read by the reading means, and a correction value for matching the pixel value of the obtained imaging data with a value corresponding to the reflectance of the reference member is set. calculate.

  In order to enable the calibration of the reading means using such a reference member, the image reading apparatus is provided with a mechanism for installing the reference member in the reading range of the reading means. For example, Patent Document 1 includes means for moving a white plate as a reference member between a reading unit and a placement surface on which a recording medium to be read is placed when the reading unit is calibrated. An image reading apparatus is disclosed.

Japanese Patent Laying-Open No. 2015-76748

  However, in the above conventional technique, the distance from the reading unit to the recording medium when reading the recording medium is different from the distance from the reading unit to the reference member when reading the reference member. Optical conditions for reading are different. For this reason, even if the reading means is calibrated based on the imaging data of the reference member, an error due to the difference in the optical conditions occurs in the reading result of the recording medium. As described above, the conventional technique has a problem that the reading unit cannot be properly calibrated because appropriate imaging data of the reference member cannot be generated.

  An object of the present invention is to provide an image reading apparatus, an image recording apparatus, and an image reading apparatus control method capable of generating imaging data of a more appropriate reference member.

In order to achieve the above object, the invention of the image reading apparatus according to claim 1 comprises:
A reading means for detecting reflected light on the surface of the reading target by an image sensor and reading the surface of the reading target;
A reading control means for causing the reading means to perform a recording medium reading operation for reading the surface of the recording medium and a reference member reading operation for reading the surface of a predetermined reference member;
Imaging data generating means for generating reference member imaging data used for calibration of the reading means related to the detection value of the imaging element based on the detection value of the imaging element in the reference member reading operation;
A moving unit that performs a moving operation of moving at least one of the reading unit and the reference member along an incident axis direction of light incident on the imaging element from the surface of the reading target;
With
In the reference member reading operation, the reading control unit is configured such that a distance in the incident axis direction between the surface of the reference member and the light incident surface of the reading unit is a recording medium when the recording medium reading operation is performed. The moving means performs the moving operation so as to be a standard distance set in advance as a distance in the incident axis direction between the surface and the light incident surface, and the distance from the light incident surface is the standard distance. The reference member at the position is read by the reading means.

The invention according to claim 2 is the image reading apparatus according to claim 1,
The moving means has a reading means moving section for moving the reading means in the incident axis direction.

The invention according to claim 3 is the image reading apparatus according to claim 2,
The moving means includes a reference member moving unit that moves the reference member between a facing position facing the light incident surface and a retracted position deviating from the facing position.
The reading control unit moves the reference member to the facing position by the reference member moving unit when the reference member reading operation is performed by the reading unit.

According to a fourth aspect of the present invention, in the image reading apparatus according to the third aspect,
The reading unit moving unit and the reference member moving unit are configured so that the movement of the reading unit by the reading unit moving unit and the movement of the reference member by the reference member moving unit can be interlocked. It is characterized by.

According to a fifth aspect of the present invention, in the image reading device according to the fourth aspect,
The reading means moving unit moves the reading means between a recording medium reading position when the recording medium reading operation is performed and a reference member reading position when the reference member reading operation is performed,
The reference member moving unit is configured such that when the reading unit is at the recording medium reading position, the reference member is disposed at a predetermined retracted position with respect to the reading unit, and when the reading unit is at the reference member reading position. The reference member is moved so that the reference member is disposed at a predetermined read position with respect to the reading means that faces the light incident surface and the distance between the light incident surface and the reference member is the standard distance. It is characterized by that.

The invention according to claim 6 is the image reading apparatus according to any one of claims 3 to 5,
The reading unit has a line sensor that outputs a one-dimensional image, and reads the reading range extending in a predetermined direction on the surface of the reference member by the line sensor,
The imaging data generation unit is configured to read the reference member from a plurality of reading ranges obtained by reading the plurality of reading ranges according to the movement of the reference member by the reference member moving unit on the surface of the reference member. It is characterized by generating imaging data.

The invention according to claim 7 is the image reading apparatus according to any one of claims 2 to 6,
A mounting member having a mounting surface on which the recording medium is mounted;
In the recording medium reading operation, the reading control unit performs the reading so that a distance between the surface of the recording medium placed on the mounting surface and the light incident surface in the incident axis direction becomes the standard distance. The reading means is moved by a means moving section, and the recording medium at a position where the distance from the light incident surface is the standard distance is read by the reading means.

The invention according to claim 8 is the image reading apparatus according to claim 7,
Thickness information acquisition means for acquiring information related to the thickness of the recording medium,
In the recording medium reading operation, the reading control unit is configured to determine a distance in the incident axis direction between the surface of the recording medium placed on the mounting surface and the light incident surface based on the acquired information. The reading unit is moved by the reading unit moving unit so as to be the standard distance.

The invention according to claim 9 is the image reading apparatus according to claim 7,
Comprising a detecting means for detecting a position of the surface of the recording medium placed on the placing surface in the incident axis direction;
In the recording medium reading operation, the reading control unit is configured to determine a distance in the incident axis direction between the surface of the recording medium placed on the mounting surface and the light incident surface based on the detected position. The reading unit is moved by the reading unit moving unit so as to be the standard distance.

According to a tenth aspect of the present invention, in the image reading apparatus according to any one of the seventh to ninth aspects,
A transport means for transporting the recording medium placed on the placement surface by moving the placement member;
In the recording medium reading operation, the reading control unit causes the reading unit to read the recording medium conveyed by the conveying unit.

According to an eleventh aspect of the present invention, in the image reading apparatus according to the tenth aspect,
The mounting member is a drum,
The transport means transports the recording medium by rotating the drum along a cylindrical axis of the drum in a state where the recording medium is placed on the outer peripheral curved surface of the drum.

The invention according to claim 12 is the image reading apparatus according to any one of claims 1 to 11,
Calibration means for performing the calibration based on the reference member imaging data is provided.

In order to achieve the above object, the invention of the image recording apparatus according to claim 13
Recording means for recording an image on a recording medium;
The image reading apparatus according to any one of claims 1 to 12, wherein an image recorded on the recording medium is read by the recording unit;
It is characterized by having.

In order to achieve the above object, an invention of a control method for an image reading apparatus according to claim 14 comprises:
Reading means for detecting reflected light on the surface of the reading target by the image sensor and reading the surface of the reading target, and light that enters at least one of the reading means and the predetermined reference member from the surface of the reading target to the imaging element A moving unit that performs a moving operation of moving along the incident axis direction of the image reading apparatus,
A recording medium reading step for reading the surface of the recording medium by the reading means;
A reference member reading step for causing the reading means to read the surface of the reference member;
An imaging data generation step for generating reference member imaging data used for calibration of the reading unit related to the detection value of the imaging element based on the detection value of the imaging element in the reference member reading step;
Including
In the reference member reading step, the distance in the incident axis direction between the surface of the reference member and the light incident surface of the reading means is the surface of the recording medium and the light incident surface when the recording medium reading step is performed. The moving means performs the moving operation so that a standard distance set in advance as a distance in the incident axis direction with respect to the incident axis direction, and the reference is located at a position where the distance from the light incident surface is the standard distance. The member is read by the reading means.

  According to the present invention, there is an effect that imaging data of a more appropriate reference member can be generated.

It is a figure which shows schematic structure of an inkjet recording device. 2 is a schematic cross-sectional view illustrating a configuration of an image reading unit. FIG. It is a block diagram which shows the main function structures of an inkjet recording device. It is a figure which shows the example of the normal image recorded on a recording medium, and a test chart. It is a figure explaining the reading operation | movement of the standard white board by an image reading part. It is a figure explaining the reading operation | movement of the standard white board by an image reading part. It is a flowchart which shows the control procedure of an image recording process. It is a flowchart which shows the control procedure of an image reading part calibration process. It is a figure explaining operation | movement of the moving mechanism of the standard white board concerning 2nd Embodiment. It is a figure explaining operation | movement of the moving mechanism of the standard white board concerning 2nd Embodiment. It is a figure explaining operation | movement of the moving mechanism of the standard white board concerning 2nd Embodiment. It is a figure explaining operation | movement of the white board parallel displacement mechanism which concerns on the modification 1. FIG. It is a figure explaining operation | movement of the white board parallel displacement mechanism which concerns on the modification 1. FIG. It is a schematic diagram explaining the operation | movement of the white board moving part which concerns on the modification 2. It is a schematic diagram explaining the operation | movement of the white board moving part which concerns on the modification 2. It is a schematic diagram explaining the operation | movement of the white board moving part which concerns on the modification 2.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of an image reading apparatus, an image recording apparatus, and an image reading apparatus control method according to the invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of an ink jet recording apparatus 1 (image recording apparatus) according to an embodiment of the present invention.
The ink jet recording apparatus 1 includes a paper feeding unit 10, an image recording unit 20, a paper discharge unit 30, and a control unit 40 (FIG. 3). Under the control of the control unit 40, the inkjet recording apparatus 1 conveys the recording medium P stored in the paper feeding unit 10 to the image recording unit 20, and the image recording unit 20 records an image on the recording medium P. The recorded recording medium P is conveyed to the paper discharge unit 30. As the recording medium P, in addition to paper such as plain paper and coated paper, various media capable of fixing ink landed on the surface, such as cloth or sheet-like resin, can be used.

  The paper supply unit 10 includes a paper supply tray 11 that stores the recording medium P, and a medium supply unit 12 that conveys and supplies the recording medium P from the paper supply tray 11 to the image recording unit 20. The medium supply unit 12 includes a ring-shaped belt supported on the inside by two rollers, and the recording medium P is removed from the paper feed tray 11 by rotating the roller while the recording medium P is placed on the belt. It is conveyed to the image recording unit 20.

  The image recording unit 20 includes a conveying unit 21 (conveying unit), a delivery unit 22, a heating unit 23, a head unit 24 (recording unit), a fixing unit 25, an image reading unit 26 (reading unit), and a delivery. Part 28 and the like.

  The transport unit 21 holds a recording medium P placed on a transport surface 211a (mounting surface) of a cylindrical transport drum 211 (mounting member), and the transport drum 211 is perpendicular to the drawing in FIG. A transport operation for transporting the transport drum 211 and the recording medium P on the transport drum 211 in the transport direction is performed by rotating around the rotation shaft (cylindrical shaft) extending in the direction (X direction). The transport drum 211 includes a claw portion and a suction portion (not shown) for holding the recording medium P on the transport surface 211a. The recording medium P is held on the conveyance surface 211a by the end being pressed by the claw portion and sucked to the conveyance surface 211a by the intake portion. The transport unit 21 is connected to a transport drum motor (not shown) for rotating the transport drum 211, and the transport drum 211 rotates by an angle proportional to the rotation amount of the transport drum motor.

  The delivery unit 22 delivers the recording medium P conveyed by the medium supply unit 12 of the paper supply unit 10 to the conveyance unit 21. The delivery unit 22 is provided at a position between the medium supply unit 12 and the conveyance unit 21 of the paper supply unit 10, and picks up one end of the recording medium P conveyed from the medium supply unit 12 by the swing arm unit 221. Then, it is delivered to the transport unit 21 via the delivery drum 222.

  The heating unit 23 is provided between the arrangement position of the delivery drum 222 and the arrangement position of the head unit 24, and the recording medium P conveyed by the conveyance unit 21 has a temperature within a predetermined temperature range. Heat P. The heating unit 23 includes, for example, an infrared heater and energizes the infrared heater based on a control signal supplied from the CPU 41 (FIG. 3) to cause the infrared heater to generate heat.

  The head unit 24 moves from the nozzle opening provided on the ink ejection surface facing the conveyance surface 211a of the conveyance drum 211 to the recording medium P at an appropriate timing according to the rotation of the conveyance drum 211 holding the recording medium P. In contrast, ink is ejected to record an image. The head unit 24 is disposed such that the ink discharge surface and the transport surface 211a are separated by a predetermined distance. In the ink jet recording apparatus 1 of the present embodiment, four head units 24 respectively corresponding to four color inks of yellow (Y), magenta (M), cyan (C), and black (K) are transported in the recording medium P. They are arranged so as to be arranged at predetermined intervals in the order of Y, M, C, and K colors from the upstream side.

Each head unit 24 has a plurality of (for example, four) recordings in which a plurality of recording elements are arranged in a direction intersecting the transport direction of the recording medium P (in this embodiment, a direction orthogonal to the transport direction, that is, the X direction). A head 242 (FIG. 3) and a recording head drive unit 241 (FIG. 3) for driving the recording head 242 are provided.
Each of the recording elements provided in the recording head 242 includes a pressure chamber for storing ink, a piezoelectric element provided on a wall surface of the pressure chamber, and a nozzle. When a drive signal for deforming the piezoelectric element is input to the recording element, the pressure chamber is deformed by the deformation of the piezoelectric element, the pressure in the pressure chamber is changed, and ink is ejected from a nozzle communicating with the pressure chamber. In the recording head 242, when a nozzle with defective ink ejection (defective nozzle) occurs due to processing variations at the time of nozzle formation, piezoelectric element characteristic variations, nozzle clogging, or clogging due to foreign matter adhering to the nozzle openings. There is.

  The arrangement range of the recording elements included in the head unit 24 in the X direction covers the width in the X direction of the area where the image is recorded in the recording medium P transported by the transport drum 211. The position is fixed with respect to the transport drum 211 during image recording. That is, the inkjet recording apparatus 1 is an inkjet recording apparatus that performs single-pass image recording using a line head.

As the ink ejected from the nozzles of the recording element, ink that has a property of changing in a gel or sol state depending on the temperature and being cured by irradiating energy rays such as ultraviolet rays is used.
In this embodiment, ink that is gel-like at room temperature and becomes sol-like when heated is used. The head unit 24 includes an ink heating unit (not shown) that heats the ink stored in the head unit 24, and the ink heating unit operates under the control of the CPU 41 and heats the ink to a sol-like temperature. . The recording head 242 discharges ink that has been heated to form a sol. When the sol-like ink is ejected onto the recording medium P, the ink droplets land on the recording medium P and then spontaneously cool, so that the ink quickly becomes a gel and solidifies on the recording medium P.

  The fixing unit 25 has an energy beam irradiation unit arranged over the width of the conveyance unit 21 in the X direction, and the recording medium P placed on the conveyance unit 21 receives ultraviolet rays or the like from the energy beam irradiation unit. The ink ejected on the recording medium P is cured and fixed by irradiating energy rays. The energy beam irradiation unit of the fixing unit 25 is arranged to face the conveyance surface 211a between the arrangement position of the head unit 24 and the arrangement position of the delivery drum 281 of the delivery unit 28 in the conveyance direction.

The image reading unit 26 is arranged to be able to read the conveyance surface 211a and the surface of the recording medium P on the conveyance surface 211a at a position between the fixing position of the ink by the fixing unit 25 and the arrangement position of the transfer drum 281 in the conveyance direction. Is done. In the present embodiment, the image reading unit 26 reads the surface of the recording medium P conveyed by the conveying unit 21 and the surface of a predetermined standard white plate (reference member) whose reflectance is uniform and known. A white plate reading operation (reference member reading operation) is performed. The image reading unit 26 outputs imaging data of the surface of the reading target (recording medium and standard white plate) to the control unit 40 in the recording medium reading operation and the white plate reading operation.
Further, the image reading unit 26 is used after being calibrated so that the pixel values in the imaging data when the standard white plate is read are uniform with a predetermined value. A method for calibrating the image reading unit 26 will be described later.

FIG. 2 is a schematic cross-sectional view illustrating the configuration of the image reading unit 26. FIG. 2 schematically illustrates the configuration of the image reading unit 26 in a cross section perpendicular to the X direction.
The image reading unit 26 includes a housing 261, a pair of light sources 262 housed inside the housing 261, mirrors 2631 and 2632, an optical system 264, and a line sensor 265.

  The housing 261 is a rectangular parallelepiped member disposed so that one surface faces the transport surface 211a. The surface of the housing 261 that faces the transport surface 211a is a light transmission surface 261a (light incident surface) that is configured using a light-transmitting member such as glass. Hereinafter, the transport direction of the recording medium P at the position facing the light transmission surface 261a is defined as the Y direction, and the direction perpendicular to the XY plane is defined as the Z direction.

  Each of the pair of light sources 262 is a linear light source having a plurality of LEDs 262a (Light Emitting Diodes) arranged in a range including an image recordable range by the head unit 24 in the X direction. The pair of light sources 262 is disposed at a position opposite to a predetermined reference plane A perpendicular to the transport direction, and emits light to the recording medium P on the transport surface 211a through the light transmission surface 261a of the housing 261. Further, the angle of each light source 262 is on a line intersecting the reference plane A of the recording medium P when the distance between the light transmission surface 261a and the recording medium P on the transport surface 211a is a predetermined standard distance d. It is adjusted so that light is irradiated at the same incident angle.

  The mirror 2631 has a length corresponding to the arrangement range of the light source 262 in the X direction, and reflects light traveling on the reference plane A out of light emitted from the light source 262 and reflected by the recording medium P in the direction of the mirror 2632. . The mirror 2632 is provided at a position closer to the light transmission surface 261 a than the mirror 2631, and reflects the light reflected by the mirror 2631 toward the optical system 264. By providing the mirrors 2631 and 2632 in this manner, an appropriate optical path length is secured in the housing 261.

  The optical system 264 condenses incident light from the mirror 2632 at the position of the image sensor 265 a of the line sensor 265. The optical system 264 forms an image at the position of the image sensor 265a of the line sensor 265 when the distance between the light transmission surface 261a and the recording medium P on the transport surface 211a is a predetermined standard distance d. That is, it is adjusted so that the surface of the recording medium P is in focus. As the optical system 264, for example, an optical system in which a large number of refractive index distribution type lenses that collect incident light at a predetermined position by a refractive index distribution in a direction perpendicular to the optical axis can be used.

The line sensor 265 outputs a one-dimensional image using a plurality of image sensors 265a arranged in the X direction that output signals corresponding to the intensity of incident light. Specifically, in the line sensor 265, three rows of image pickup devices 265a are provided in the X direction, and R (red), G (green), and B (blue) wavelength components of incident light are detected by the image pickup devices 265a of each row. A signal corresponding to the intensity is output. The image sensor 265a corresponding to each of R, G, and B includes, for example, a light receiving portion of a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor that includes a photodiode as a photoelectric conversion element. A filter in which a color filter that transmits light having a wavelength component of B is disposed can be used. In the image reading unit 26, an area sensor may be used instead of the line sensor 265.
The signal output from the line sensor 265 is subjected to current-voltage conversion, amplification, noise removal, analog-digital conversion, and the like in an analog front end (not shown), and is output to the control unit 40 as imaging data indicating the luminance value of the read image. . In the present embodiment, the pixel value of the imaging data indicates the detection intensity of light by the imaging element 265a in 256 gradations from 0 to 255.

  The image reading unit 26 is attached to a reading position adjusting unit 27 (FIG. 3) (moving unit, reading unit moving unit). Based on a control signal from the CPU 41, the reading position adjustment unit 27 causes the image reading unit 26 to enter the image pickup element 265a from the surface of the recording medium P and the standard white plate (in this embodiment, the + Z direction and − Z direction). For example, the reading position adjustment unit 27 adjusts the height of the image reading unit 26 so that the distance between the light transmission surface 261a and the recording medium P becomes a predetermined standard distance d when the above-described recording medium reading operation is performed. To do. The configuration of the reading position adjusting unit 27 is not particularly limited. For example, a column portion extending in the Z direction and a housing 261 of the image reading unit 26 are fixed, and the rotation of the stepping motor causes the + Z direction and − It can be set as the structure provided with the moving part which can move to a Z direction.

  The delivery unit 28 includes a belt loop 282 having a ring-shaped belt supported on the inside by two rollers, and a cylindrical transfer drum 281 that transfers the recording medium P from the transport unit 21 to the belt loop 282. The recording medium P transferred from the transport unit 21 onto the belt loop 282 by the transfer drum 281 is transported by the belt loop 282 and sent to the paper discharge unit 30.

  The paper discharge unit 30 includes a plate-shaped paper discharge tray 31 on which the recording medium P sent out from the image recording unit 20 by the delivery unit 28 is placed.

FIG. 3 is a block diagram showing the main functional configuration of the inkjet recording apparatus 1.
The ink jet recording apparatus 1 includes a heating unit 23, a recording head driving unit 241, a recording head 242, a fixing unit 25, an image reading unit 26, a reading position adjusting unit 27, and a white plate moving unit 29 (moving means, reference). A member moving unit), a control unit 40, a conveyance driving unit 51, an operation display unit 52, a detection unit 53, an input / output interface 54, a bus 55, and the like.
In the present embodiment, the image recording unit 1 excludes the heating unit 23, the head unit 24 (the recording head driving unit 241 and the recording head 242), and the fixing unit 25 in the inkjet recording apparatus 1. A reader is configured.

  The recording head driving unit 241 supplies pixel signals of image data from the nozzles of the recording head 242 by supplying a driving signal for deforming the piezoelectric element according to the image data at an appropriate timing to the recording elements of the recording head 242. An amount of ink corresponding to the ink is discharged.

  The white plate moving unit 29 moves the standard white plate in the Y direction between a facing position facing the light transmitting surface 261a and a retracted position not facing the light transmitting surface 261a. Further, the white plate moving unit 29 moves the standard white plate to the facing position when the image reading unit 26 performs the above-described white plate reading operation. The configuration of the white plate moving unit 29 is not particularly limited. For example, a support unit that extends in the Y direction and a standard white plate are fixed, and the support unit can be moved in the + Y direction and the -Y direction by rotating the stepping motor. It can be set as the structure provided with the part. The white plate moving unit 29 operates based on a control signal from the control unit 40.

  The control unit 40 includes a CPU 41 (Central Processing Unit) (reading control unit, imaging data generation unit, thickness information acquisition unit, calibration unit), a RAM 42 (Random Access Memory), a ROM 43 (Read Only Memory), and a storage unit 44. .

  The CPU 41 reads various control programs and setting data stored in the ROM 43, stores them in the RAM 42, executes the programs, and performs various arithmetic processes. The CPU 41 controls the overall operation of the inkjet recording apparatus 1.

  The RAM 42 provides a working memory space to the CPU 41 and stores temporary data. The RAM 42 may include a nonvolatile memory.

  The ROM 43 stores various control programs executed by the CPU 41, setting data, and the like. In place of the ROM 43, a rewritable nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used.

  In the storage unit 44, a print job (image recording command) input from the external device 2 via the input / output interface 54, image data related to the print job, test image data which is image data of a test chart described later, and Data captured by the image reading unit 26 is stored. Among these, the print job includes information related to the type of the recording medium P on which the image is recorded (for example, the size and thickness of the recording medium P) in addition to the information specifying the image data related to the image to be recorded. The storage unit 44 stores image reading unit calibration data 44 a related to the calibration result of the image reading unit 26. As the storage unit 44, for example, an HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may be used in combination.

  The transport drive unit 51 supplies a drive signal to the transport drum motor of the transport drum 211 based on a control signal supplied from the CPU 41 to rotate the transport drum 211 at a predetermined speed and timing. Further, the transport driving unit 51 supplies a drive signal to a motor for operating the medium supply unit 12, the delivery unit 22, and the delivery unit 28 based on a control signal supplied from the CPU 41, so that the recording medium P is transported. Supply to the unit 21 and discharge from the transport unit 21 are performed.

  The operation display unit 52 includes a display device such as a liquid crystal display and an organic EL display, and operation keys and an input device such as a touch panel disposed on the screen of the display device. The operation display unit 52 displays various information on the display device, converts a user input operation to the input device into an operation signal, and outputs the operation signal to the control unit 40.

  The detection unit 53 includes a light detection unit (not shown) that detects the luminance of the LED 262 a of the image reading unit 26, and outputs a detection result of the luminance to the control unit 40.

  The input / output interface 54 mediates data transmission / reception between the external device 2 and the control unit 40. The input / output interface 54 is configured by, for example, one of various serial interfaces, various parallel interfaces, or a combination thereof.

  The bus 55 is a path for transmitting and receiving signals between the control unit 40 and other components.

  The external device 2 is, for example, a personal computer, and supplies a print job, image data, and the like to the control unit 40 via the input / output interface 54.

Next, an ink ejection defect inspection in the inkjet recording apparatus 1 of the present embodiment will be described.
In the ink jet recording apparatus 1 of the present embodiment, a test chart for detecting the presence or absence of ink ejection failure is recorded on the recording medium P together with a normal image related to a print job, and the reading result of the test chart by the image reading unit 26 is recorded. Based on this, the presence or absence of an ink ejection defect, that is, the presence or absence of a defective nozzle is detected.

FIG. 4 is a diagram illustrating an example of a normal image 60 and a test chart 61 recorded on the recording medium P.
The test chart 61 is composed of four strip-shaped halftone images that are recorded on the upstream side in the transport direction of the normal image 60 when the recording medium P is transported, and each recorded with each color ink of YMCK. The test chart 61 is recorded in an image recordable range by the head unit 24 in the width direction. If there is a defective nozzle in any of the head units 24, color unevenness E occurs in the test chart 61 due to defective ink ejection by the defective nozzle.
In the inkjet recording apparatus 1, when the test chart 61 is read by the image reading unit 26 and color unevenness E is detected in the obtained imaging data, it is determined that there is a defective nozzle.

When it is determined that there is a defective nozzle, a predetermined coping operation is performed to suppress deterioration in the image quality of the recorded image due to the defective nozzle.
In this coping operation, for example, a defective nozzle specifying chart including a line pattern for specifying a defective nozzle is recorded on the recording medium P, and the defective nozzle is specified based on the reading result by the image reading unit 26 of the defective nozzle specifying chart. Is done. Then, after the image data related to the normal image is corrected so that the ink ejection by the defective nozzle is not performed and the non-ejection of the ink is complemented by the increase in the ink ejection amount from the peripheral nozzles. A normal image is recorded. Further, when the supplement cannot be performed, maintenance operations such as wiping the ink ejection surface of the recording head 242 and pressurizing purge for forcibly ejecting ink from the nozzles by pressurizing the ink in the recording head 242 are performed. Thus, the defective nozzle is restored to a normal state.

As described above, in the ink jet recording apparatus 1 of the present embodiment, the ink ejection defect inspection is performed based on the reading result of the test chart 61 by the image reading unit 26. For this reason, in the inkjet recording apparatus 1, when the predetermined image reading unit calibration start condition is satisfied so that the test chart 61 is appropriately read by the image reading unit 26, the image reading unit related to the detection values by the plurality of imaging elements 265a. A calibration operation is performed to perform 26 calibrations. Here, in this embodiment, the image reading unit calibration start condition may be that the detection result of the detection unit 53 indicates that the luminance of the LED 262a has changed by a predetermined value or more after the most recent calibration operation. . Note that the image reading unit calibration start condition is not limited to this. For example, the temperature near the LED 262a that changes in response to the luminance change of the LED 262a, the elapsed time after the light source 262 starts lighting, and the inkjet recording apparatus 1 record an image. It can be determined based on the number of recording media P. In addition, when the image reading unit 26 performs reading for the first time after the ink jet recording apparatus 1 is turned on or after the light source 262 is turned on, the image reading unit 26 is calibrated prior to the reading.
Hereinafter, the calibration operation of the image reading unit 26 will be described.

  In the calibration operation of the image reading unit 26 in the present embodiment, first, the image reading unit 26 reads a plurality of different line-shaped reading ranges (hereinafter also simply referred to as “lines”) on the surface of the standard white plate, White plate imaging data composed of line imaging data is generated. Here, the standard white plate is a plate-like member having a reading surface larger than the range that can be read by the line sensor 265. In the calibration operation of the image reading unit 26, the reading surface faces the light transmission surface 261a. Placed in. The reading surface of the standard white plate is made of a white member having a uniform reflectance such as YUPO or PET (polyethylene terephthalate). The reading surface is preferably made of a material that can easily remove foreign matters such as dust attached to the surface by cleaning the surface.

FIG. 5 is a diagram for explaining the reading operation of the standard white plate 70 by the image reading unit 26. 5A is a diagram showing the position of the image reading unit 26 (hereinafter referred to as a recording medium reading position) when the recording medium P is read by the image reading unit 26, and FIG. It is a figure which shows the position of the image reading part 26 in the case of reading the white board 70 (it is hereafter described as a white board reading position (reference member reading position)).
The recording medium reading position shown in FIG. 5A is a position where the distance in the Z direction between the light transmission surface 261a and the surface of the recording medium P is the standard distance d. The recording medium reading position is adjusted by changing the position of the image reading unit 26 in the Z direction by the reading position adjusting unit 27 based on the information relating to the thickness of the recording medium P included in the print job data.

  When the image reading unit 26 reads the standard white plate 70 and the image reading unit 26 is in the recording medium reading position, the reading position adjusting unit 27 causes the image reading unit 26 to reach the predetermined white plate reading position in the + Z direction. Moved. Here, the white plate reading position is a standard white color between the light transmitting surface 261a and the transport drum 211 in a positional relationship where the distance between the light transmitting surface 261a of the image reading unit 26 and the standard white plate 70 is the standard distance d. The position where the plate 70 can be arranged is set to a position close to the conveying drum 211 among the positions satisfying such conditions, so that the moving distance of the image reading unit 26 in the calibration operation can be shortened.

After the image reading unit 26 has moved to the white plate reading position, as shown in FIG. 5B, the white plate moving unit 29 causes the Z direction between the image reading unit 26 and the transport drum 211 and the light transmission surface 261 a to move in the Z direction. The standard white plate 70 is disposed at a position where the distance becomes the standard distance d (opposing position, read position), and the standard white plate 70 is moved in the Y direction. A direction intersecting with the Y direction on the surface of the standard white plate 70 by the image reading unit 26 at an appropriate timing according to the movement of the standard white plate 70 (in this embodiment, a direction orthogonal to the Y direction, that is, the X direction). ) Are repeatedly read to generate white plate imaging data.
Here, the reading range and the number of readings of the standard white plate 70 in the Y direction by the image reading unit 26 are not particularly limited, but in the present embodiment, 512 readings are performed within a range of 2 mm in the Y direction. . Therefore, in the inkjet recording apparatus 1, the moving speed of the standard white plate 70 by the white plate moving unit 29 is set according to the reading frequency by the image reading unit 26 so that the image reading unit 26 can perform such reading. ing.
The moving direction of the standard white plate 70 by the white plate moving unit 29 does not necessarily have to be orthogonal to the moving direction of the image reading unit 26 by the reading position adjusting unit 27.
In the present embodiment, the operation of the reading position adjustment unit 27 that moves the image reading unit 26 to the white plate reading position, and the standard white plate 70 so that the distance between the standard white plate 70 and the light transmission surface 261a is the standard distance d. The operation of the white plate moving unit 29 for arranging the images corresponds to the moving operation.

  Thus, in this embodiment, reading is performed in a state where the distance between the surface to be read and the light transmission surface 261a is the standard distance d in both the recording medium reading operation and the white plate reading operation. Further, since the relative position between the light source 262 and the light transmission surface 261a is fixed, the distance between the surface to be read and the light source 262 in each of the recording medium reading operation and the white plate reading operation is also the same. Therefore, the recording medium P and the standard white plate 70 are read under the same optical conditions.

  When the white plate imaging data is generated, an average value of pixel values of a plurality of pixels corresponding to the same imaging element 265a is calculated from the white plate imaging data, and the average value is used as the pixel value. Calibration image data including the same number of pixels as 265a is generated. Note that, among a plurality of pixels corresponding to the same image sensor 265a, a pixel having an abnormal pixel value due to a foreign substance such as dust (for example, a value lower than the pixel value of surrounding pixels) is excluded, The pixel values of the remaining pixels may be averaged.

When the calibration image data is generated, a correction value that matches each pixel value of the calibration image data with a value corresponding to the reflectance of the standard white plate is calculated. That is, among the pixels of the calibration image data, the correction value for correcting the pixel value I (i) of the pixel corresponding to the i-th image sensor 265a (i is a natural number indicating the array element number of the image sensor 265a) in the X direction. C (i) is calculated for all i by the following formula (1).
C (i) = Ia / I (i) (1)
Here, Ia is a constant corresponding to the reflectance of the standard white plate 70, and is set to a value (240 in the present embodiment) that is lower than the maximum pixel value 255 by a predetermined value. This is to avoid saturation (exceeding 255) of a value obtained by multiplying the pixel value I (i) by the correction value C (i) when a reading target having a reflectance higher than that of the standard white plate 70 is read. It is.
The correction value C (i) is calculated for each of the columns of the image sensor 265a corresponding to R, G, and B in the line sensor 265, and is stored in the storage unit 44 as the image reading unit calibration data 44a.
When the image reading unit calibration data 44a is stored in the storage unit 44, the calibration operation of the image reading unit 26 is finished.

When the test chart 61 is read by the image reading unit 26 after the calibration operation of the image reading unit 26 is performed, a correction value for the pixel value corresponding to the i-th imaging element 265a in the imaging data. The corrected imaging data (image data) obtained by multiplying C (i) is stored in the storage unit 44 as a read result.
In this way, by multiplying the pixel value of the imaging data by the correction value C (i), the pixel resulting from the sensitivity variation for each imaging element 265a and the illuminance unevenness of the light source 262 near the end in the X direction. The decrease in value is corrected, and the test chart 61 is read appropriately.

  Subsequently, a control procedure by the CPU 41 of an image recording process related to an image recording operation by the inkjet recording apparatus 1 and an image reading unit calibration process related to a calibration operation of the image reading unit 26 will be described.

FIG. 6 is a flowchart showing a control procedure by the CPU 41 of the image recording process.
This image recording process is executed when a print job and image data are input from the external apparatus 2 to the control unit 40 via the input / output interface 54.
Prior to the start of the image recording process, the CPU 41 causes the conveyance driving unit 51 to output a drive signal to the conveyance drum motor of the conveyance drum 211 to start the rotation operation of the conveyance drum 211. When the light source 262 is not lit, the CPU 41 outputs a control signal to the light source 262 to turn on the light source 262.

  When the image recording process is started, the CPU 41 determines whether or not an image reading unit calibration process start condition is satisfied (step S101). That is, the CPU 41 determines that the image reading unit calibration processing start condition is satisfied when the luminance of the LED 262a by the light detection unit of the detection unit 53 has fluctuated by a predetermined value or more from the time point related to the latest image reading unit calibration processing. . Further, the CPU 41 satisfies the condition for starting the image reading unit calibration process when the image recording process being executed is the image recording process that is executed first after the inkjet recording apparatus 1 is turned on or after the light source 262 is turned on. Is determined.

  When it is determined that the image reading unit calibration process start condition is satisfied (“Yes” in step S101), the CPU 41 executes an image reading unit calibration process to be described later (step S102).

  When the image reading unit calibration process is completed, or when it is determined in the process of step S101 that the image reading unit calibration process start condition is not satisfied (“No” in step S101), the CPU 41 causes the reading position adjustment unit 27 to In response to this, a control signal is output, and the reading position adjustment unit 27 moves the image reading unit 26 to the recording medium reading position shown in FIG. 5A (step S103). That is, the CPU 41 acquires information related to the thickness of the recording medium P on which an image is recorded in the image recording process from print job data, and the distance between the light transmission surface 261a of the image reading unit 26 and the surface of the recording medium P. The image reading unit 26 is moved in the Z direction or the −Z direction by the reading position adjusting unit 27 such that the standard distance d is reached.

  The CPU 41 causes the head unit 24 to record the normal image 60 and the test chart 61 on the recording medium P (step S104). That is, the CPU 41 supplies the image data of the normal image 60 and the test image data of the test chart 61 stored in the storage unit 44 from the recording head driving unit 241 to the recording head 242 at an appropriate timing according to the rotation of the transport drum 211. As a result, the head unit 24 causes the ink to be ejected onto the recording medium P to record the normal image 60 and the test chart 61 on the recording medium P. In addition, the CPU 41 fixes the ink to the recording medium P by irradiating the ink with a predetermined energy beam at the timing when the recording medium P to which the ink has been applied has moved to the position of the fixing unit 25.

  The CPU 41 causes the image reading unit 26 to image the test chart 61 on the recording medium P (step S105: recording medium reading step). That is, the CPU 41 repeatedly reads the test chart 61 on the recording medium P by the image reading unit 26 at an appropriate timing according to the rotation of the transport drum 211, acquires the imaging data, and stores it in the storage unit 44. Then, the CPU 41 refers to the image reading unit calibration data 44a stored in the storage unit 44 in step S102, and corrects the pixel value of the pixel corresponding to the i-th imaging element 265a in the imaging data of the test chart 61. The corrected image data (image data) obtained by multiplying the value C (i) is stored in the storage unit 44.

  Based on the imaging data of the test chart 61, the CPU 41 determines whether or not the test chart 61 has color unevenness E indicating an ink ejection failure, that is, whether any of the head units 24 has a defective nozzle ( Step S106).

If it is determined that there is no defective nozzle (“No” in step S106), the CPU 41 determines whether or not there is a new print job execution command (obtained) (step S107). If it is determined that it has been acquired (“Yes” in step S107), the CPU 41 shifts the processing to step S101.
If it is determined that there is no execution command for a new print job (“No” in step S107), the CPU 41 ends the image recording process.

  If it is determined that there is a defective nozzle (“Yes” in step S106), the CPU 41 ends the image recording process. When the image recording process is completed from the process of step S106, the above-described predetermined coping process is executed.

FIG. 7 is a flowchart showing a control procedure by the CPU 41 of the image reading unit calibration process.
When the image reading unit calibration process is started, the CPU 41 outputs a control signal to the reading position adjusting unit 27, and the reading position adjusting unit 27 moves the image reading unit 26 to the white plate reading position shown in FIG. 5B. Move (step S201).

  The CPU 41 causes the image reading unit 26 to image a plurality of lines on the standard white plate 70 (step S202: reference member reading step, imaging data generation step). That is, the CPU 41 outputs a control signal to the white plate moving unit 29, and the white plate moving unit 29 causes the standard white plate 70 to face the light transmitting surface 261a shown in FIG. The standard white plate 70 is moved in the Y direction at a predetermined speed by disposing it at a position where the distance to the standard distance d is 261a. Further, the CPU 41 causes the image reading unit 26 to repeatedly read the standard white plate 70 at appropriate intervals, obtains white plate imaging data, and stores it in the storage unit 44. Further, the CPU 41 averages the pixel values of a plurality of pixels corresponding to the same image sensor 265 a in the white plate imaging data, generates calibration image data, and stores the calibration image data in the storage unit 44.

The CPU 41 generates image reading unit calibration data 44a based on the calibration image data and stores it in the storage unit 44 (step S203). That is, the CPU 41 calculates the correction value C (i) from the calibration image data based on the above-described algorithm, and stores it in the storage unit 44 as the image reading unit calibration data 44a.
When the process of step S203 ends, the CPU 41 ends the image reading unit calibration process.

  As described above, the image reading apparatus according to the present embodiment detects the reflected light on the surface of the reading target by the image sensor 265a and reads the surface of the reading target, the image reading unit 26, and the standard white plate. A reading position adjusting unit 27 and a white plate moving unit 29 as moving means for performing a moving operation of moving at least one of 70 along the incident axis direction (Z direction) of light incident on the image sensor 265a from the surface of the reading target; The CPU 41 causes the image reading unit 26 to perform a recording medium reading operation for reading the surface of the recording medium P and a white plate reading operation for reading the surface of the standard white plate 70 (reading control unit). Based on the detection value of the image sensor 265a in the white plate reading operation, the white plate imaging data used for calibration of the image reading unit 26 related to the detection value of the image sensor 265a. (Imaging data generation means), and in the white plate reading operation, the distance between the surface of the standard white plate 70 and the light transmission surface 261a of the image reading unit 26 in the Z direction is the time when the recording medium reading operation is performed. The reading position adjusting unit 27 and the white plate moving unit 29 perform a moving operation so that the distance between the surface of the recording medium P and the light transmitting surface 261a is a preset standard distance d as the distance in the Z direction. The standard white plate 70 at a position where the distance from the surface 261a is the standard distance d is read by the image reading unit 26 (reading control means). According to such a configuration, the distance from the light transmission surface 261a to the recording medium P when the recording medium P is read by the image reading unit 26, and the distance from the light transmission surface 261a to the white plate when the standard white plate 70 is read. The distance can be made equal. Therefore, the recording medium P and the standard white plate 70 can be read under the same optical conditions. Therefore, according to the above configuration, it is possible to generate appropriate white plate imaging data of the standard white plate 70, and to perform appropriate calibration of the image reading unit 26 by using the white plate imaging data.

  Further, since the moving means includes the reading position adjusting unit 27 that moves the image reading unit 26 in the Z direction, the distance between the image reading unit 26 and the standard white plate 70 in the Z direction can be easily adjusted. .

  The moving means includes a white plate moving unit 29 that moves the standard white plate 70 between a facing position facing the light transmission surface 261a and a retracted position deviating from the facing position, and the CPU 41 includes the image reading unit 26. When the white plate reading operation is performed, the white plate moving unit 29 moves the standard white plate 70 to the facing position (reading control means). Accordingly, the standard white plate 70 and the recording medium P can be read by the image reading unit 26 without moving the image reading unit 26 in the Y direction.

  The image reading unit 26 includes a line sensor 265 that outputs a one-dimensional image. The line sensor 265 reads a reading range extending in the X direction on the surface of the standard white plate 70, and the CPU 41 detects the surface of the standard white plate 70. The white plate imaging data is generated from the reading results obtained by the image reading unit 26 reading a plurality of different reading ranges according to the movement of the standard white plate 70 in the Y direction by the white plate moving unit 29 (imaging data). Generating means). Accordingly, a wide range of the surface of the standard white plate 70 can be read by the image reading unit 26 having a simple configuration. As a result, it is possible to extract pixel values and process pixel values of the obtained white plate image data, and to generate white plate image data of the standard white plate 70 with fewer errors.

  Further, the image reading apparatus includes a transport drum 211 having a transport surface 211a on which the recording medium P is placed, and the CPU 41 performs light and light on the surface of the recording medium P placed on the transport surface 211a in the recording medium reading operation. The image reading unit 26 is moved by the reading position adjusting unit 27 so that the distance in the Z direction with respect to the transmission surface 261a is the standard distance d, and the recording medium is located at a position where the distance from the light transmission surface 261a is the standard distance d P is read by the image reading unit 26 (reading control means). Thereby, since the recording medium P can be read under the same optical conditions as when the standard white plate 70 is read, the recording medium P can be appropriately read by the image reading unit 26.

  Further, the CPU 41 acquires information related to the thickness of the recording medium P (thickness information acquisition means), and in the recording medium reading operation, the recording medium P placed on the transport surface 211a based on the acquired information. The image reading unit 26 is moved by the reading position adjusting unit 27 so that the distance in the Z direction between the surface and the light transmission surface 261a becomes the standard distance d (reading control unit). According to this, regardless of the thickness of the recording medium P, it is possible to appropriately read the recording medium P under the same optical conditions as when the standard white plate 70 is read.

  Further, the image reading apparatus includes a transport unit 21 that transports the recording medium P placed on the transport surface 211a by rotating the transport drum 211, and the CPU 41 transports the recording medium P by the transport unit 21 in the recording medium reading operation. The recording medium P to be read is read by the image reading unit 26 (reading control means). Thereby, each position in the transport direction on the recording medium P can be properly read under the same optical conditions as when reading the standard white plate 70 without moving the image reading unit 26.

  Further, the transport unit 21 transports the recording medium P by rotating the transport drum 211 along the cylindrical axis of the transport drum 211 in a state where the recording medium P is placed on the outer peripheral curved surface of the transport drum 211. According to such a configuration, since the transport operation by the transport unit 21 can be performed without deforming the transport member (transport drum 211), the recording medium P can be transported on the transport surface regardless of the position of the transport drum 211. It can be held on 211a. For this reason, on the conveyance surface 211a of the conveyance drum 211, the position where the recording medium P is supplied, the position where the recording medium P is discharged, the position where the image is recorded on the recording medium P, and the surface of the recording medium P The degree of freedom of the position where reading is performed can be increased.

  Further, the CPU 41 performs calibration based on the white plate imaging data generated as described above (calibration means). Thereby, the image reading unit 26 can be appropriately calibrated.

  The ink jet recording apparatus 1 of the present embodiment includes the head unit 24 that records an image on the recording medium P, and the above-described image reading apparatus that reads the image recorded on the recording medium P by the head unit 24. . According to such an ink jet recording apparatus 1, it is possible to record an image on the recording medium P and appropriately read the image.

  Further, the control method of the image reading apparatus of the present embodiment is a reading in which the image reading unit 26 performs a recording medium reading operation for reading the surface of the recording medium P and a white plate reading operation for reading the surface of the standard white plate 70. An imaging data generation step for generating white plate imaging data used for calibration of the image reading unit 26 related to the detection value of the imaging element 265a based on the detection value of the imaging element 265a in the white plate reading operation, In the step, in the white plate reading operation, the distance between the surface of the standard white plate 70 and the light transmission surface 261a of the image reading unit 26 in the Z direction is the surface and light of the recording medium P when the recording medium reading operation is performed. The reading position adjusting unit 27 and the white plate moving unit 29 shift the standard surface to a standard distance d set in advance in the Z direction with respect to the transmission surface 261a. To perform the operation, the distance from the light transmitting surface 261a causes read by the image reading unit 26 a standard white plate 70 at the position where the standard distance d. According to such a method, the recording medium P and the standard white plate 70 can be read by the image reading unit 26 under the same optical conditions. Therefore, according to the above method, it is possible to generate appropriate white plate imaging data of the standard white plate 70, and to perform appropriate calibration of the image reading unit 26 by using the white plate imaging data.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. This embodiment is different from the above embodiment in that the standard white plate 70 moves in conjunction with the movement of the image reading unit 26. Hereinafter, differences from the above embodiment will be described.

  FIG. 8 is a diagram for explaining the operation of the moving mechanism of the standard white plate 70 according to this embodiment. 8A is a diagram illustrating a state in which the image reading unit 26 is at the recording medium reading position, and FIG. 8B is a diagram illustrating a state in which the image reading unit 26 is between the recording medium reading position and the white plate reading position. FIG. 8C is a diagram illustrating a state in which the image reading unit 26 is at the white plate reading position. A white plate moving unit 29 having an arm 291, a rotating shaft 292, and a fixing pin 293 is attached to the image reading unit 26 of the present embodiment.

  A plate-like arm 291 is attached to each of two surfaces perpendicular to the X direction in the casing 261 of the image reading unit 26 so as to be rotatable about a rotation shaft 292. Each arm 291 is attached to a frame of the inkjet recording apparatus 1 (not shown) via a fixing pin 293 that is passed through an opening 294 having a rounded rectangular shape provided on the arm 291. Here, the position of the fixing pin 293 with respect to the rotation axis of the transport drum 211 is fixed. The positional relationship between the housing 261 and the fixed pin 293 is such that when the image reading unit 26 is at the recording medium reading position, the rotation shaft 292 is on the −Z direction side with respect to the fixed pin 293, and the image reading unit 26 is white. When in the plate reading position, the rotation shaft 292 is adjusted to be on the + Z direction side with respect to the fixed pin 293. A pair of short side portions of a rectangular standard white plate 70 are fixed to ends of the pair of arms 291 opposite to the rotation shaft 292, respectively.

  With such a configuration, as the image reading unit 26 is moved from the recording medium reading position (FIG. 8A) to the white plate reading position (FIG. 8C) by the reading position adjusting unit 27 in the + Z direction, the arm 291 is moved. 8, while rotating the fixing pin 293 in the opening 294, the fixing pin 293 rotates clockwise in FIG. 8 around the fixing pin 293, and clockwise in FIG. 8 with respect to the casing 261 around the rotating shaft 292. To turn. Further, as the arm 291 is rotated, the arm 291 is disposed at a predetermined retracted position in the state shown in FIG. 8A, that is, at the −Y direction side of the housing 261 and at the + Z direction side of the light transmission surface 261a. In the state shown in FIG. 8C, the standard white plate 70 wraps around the −Z direction side of the housing 261, and the standard white plate 70 has a predetermined distance to be read, that is, a distance in the Z direction from the light transmission surface 261 a as the standard distance. It is d and is arranged at a position facing the light transmission surface 261a. In other words, the standard white plate 70 is disposed at the retracted position when the image reading unit 26 is at the recording medium reading position, and is disposed at the read position when the image reading unit 26 is at the white plate reading position. As shown in FIG.

Thus, in this embodiment, the standard white plate 70 is retracted by the white plate moving unit 29 in conjunction with the movement of the image reading unit 26 from the recording medium reading position to the white plate reading position by the reading position adjusting unit 27. To the read position. Then, the image reading unit 26 reads the surface of the standard white plate 70 arranged at the read position.
8C, an arm moving mechanism that translates the arm 291 in the Y direction relative to the housing 261, or the standard white plate 70 that is parallel to the Y direction in the state shown in FIG. 8C. By providing the white plate moving unit 29 in the white plate moving unit 29 to be moved, the image reading unit 26 can read a plurality of different positions on the standard white plate 70 while moving the standard white plate 70 in the Y direction. .

  Instead of the above configuration, the image reading unit 26 may be moved by the reading position adjusting unit 27 in conjunction with the movement of the standard white plate 70 by the white plate moving unit 29. Further, it is possible to switch between interlocking and non-interlocking between the movement of the image reading unit 26 by the reading position adjusting unit 27 and the movement of the standard white plate 70 by the white plate moving unit 29.

  As described above, in the image reading apparatus according to the present embodiment, the moving unit includes the white plate moving unit 29 that moves the standard white plate 70, and the reading position adjusting unit 27 and the white plate moving unit 29 are configured to adjust the reading position. The movement of the image reading unit 26 by the unit 27 and the movement of the standard white plate 70 by the white plate moving unit 29 can be linked. Thereby, since the mechanism and control for moving the image reading unit 26 and the standard white plate 70 can be simplified, the ink jet recording apparatus 1 can be reduced in size and cost.

  The reading position adjusting unit 27 moves the image reading unit 26 between a recording medium reading position when the recording medium reading operation is performed and a white plate reading position when the white plate reading operation is performed, The white plate moving unit 29 is configured such that when the image reading unit 26 is at the recording medium reading position, the standard white plate 70 is disposed at a predetermined retracted position with respect to the image reading unit 26 and when the image reading unit 26 is at the white plate reading position. In addition, the standard white plate 70 is disposed at a predetermined read position with respect to the image reading unit 26 facing the light transmission surface 261a and having a standard distance d between the light transmission surface 261a and the standard white plate 70. The standard white plate 70 is moved. According to such a configuration, the standard white plate 70 can be easily disposed at an appropriate position in each of the recording medium reading operation and the white plate reading operation.

(Modification 1)
Next, Modification 1 according to the second embodiment will be described.
The inkjet recording apparatus 1 according to this modification is different from the second embodiment in that it includes a white plate parallel movement mechanism that moves the standard white plate 70 in the Y direction as the image reading unit 26 moves in the Z direction. Different. Hereinafter, differences from the second embodiment will be described.

FIG. 9 is a diagram for explaining the operation of the white plate translation mechanism according to this modification.
FIG. 9A is a diagram illustrating a state in which the image reading unit 26 is at the white plate reading position. The state of FIG. 9A corresponds to the state of FIG. 8C in the second embodiment.

  In the white plate moving portion 29 of this modification, a plate-like white plate holding member 295 is attached to each end of the pair of arms 291 opposite to the rotation shaft 292. A standard white plate 70 is sandwiched between the pair of white plate holding members 295 so as to extend in the X direction. The white plate holding member 295 is attached to the arm 291 by two fixing pins 296 that are respectively passed through two opening portions 297 formed in a rounded rectangle provided in the arm 291, and the fixing pin 296 is located in the opening portion 297. Can be moved relative to the arm 291 in the Y direction in FIG. 9A.

  Moreover, the opening part 294 provided in the arm 291 is provided in the shape of a dogleg. Thereby, the arm 291 and the housing | casing 261 are further movable to a Z direction from the state of FIG. 9A to the state of FIG. 9B.

On the opposite side (+ Y direction side in FIG. 9) of the white plate holding member 295 to the arm 291 is attached a roller 298 that rotates about a rotation axis parallel to the X direction. When the image reading unit 26 is in the white plate reading position shown in FIG. 9A, the roller 298 is biased in the Y direction by the weight of the white plate holding member 295 or by an unillustrated elastic member, and moves in the Z direction. The surface of the extending guide member 299 comes into contact with the surface.
The guide member 299 has two parallel surfaces 299a parallel to the XZ plane, and an inclined surface 299b provided between the two parallel surfaces 299a and inclined with respect to the XZ plane. It moves while abutting on the two parallel surfaces 299a and the inclined surface 299b. More specifically, while the housing 261 moves from the position of FIG. 9A to the position of FIG. 9B, the roller 298 moves from one end side to the other end side of the inclined surface 299b. As the roller 298 moves, the white plate holding member 295 and the standard white plate 70 move in the Y direction while maintaining the distance from the light transmission surface 261a at the standard distance d.

  Thus, in the present modification, the standard white plate 70 moves in the + Y direction in conjunction with the movement of the image reading unit 26 in the + Z direction. By causing the image reading unit 26 to perform the reading operation a plurality of times while the standard white plate 70 is moving in the Y direction, a plurality of different positions on the standard white plate 70 can be read. Further, since the distance between the standard white plate 70 and the light transmission surface 261a is maintained at the standard distance d in the plurality of readings, the standard white plate 70 can be appropriately read under the same optical conditions. .

(Modification 2)
Next, Modification 2 according to the second embodiment will be described.
In the present modification, the configuration of the white plate moving unit 29 is different from that of the second embodiment. Hereinafter, differences from the second embodiment will be described.

FIG. 10 is a schematic diagram for explaining the operation of the white plate moving unit 29 according to this modification. FIG. 10A shows the white plate moving unit 29 in a state where the image reading unit 26 is at the recording medium reading position.
As shown in FIG. 10A, the white plate moving unit 29 according to this modification includes a white plate holding member 81 to which the standard white plate 70 is fixed. The white plate holding member 81 includes a first member 81a extending in the Z direction and a second member 81b extending in the + Y direction from the end of the first member on the + Z direction side. Among these, the first member 81a is attached to the end portion on the −Z direction side. The white plate moving unit 29 has a pair of rod-like connection members 82, one end of which is rotatably attached to the first member 81a of the white plate holding member 81 by a fixing pin 83, and a pair of connections. A support member 85 rotatably attached to the end portion of the member 82 opposite to the white plate holding member 81 via a fixing pin 84, and an elastic member 86 connected to one of the pair of connection members 82. Prepare. Among these, the support member 85 has a fixed position relative to the rotation axis of the transport drum 211.

  The white plate holding member 81 is configured such that the second member 81b contacts the image reading unit 26 when the image reading unit 26 moves in the + Z direction from the predetermined position shown in FIG. 10B. In the white plate holding member 81, the distance between the light transmission surface 261a of the image reading unit 26 and the standard white plate 70 in the Z direction is the standard distance d in a state where the second member 81b is in contact with the image reading unit 26. The length of the first member 81a in the Z direction is determined so that

  When the image reading unit 26 further moves in the + Z direction as shown in FIG. 10C from the state shown in FIG. 10B, the white plate holding member 81 moves in the + Z direction along with the movement. At this time, as the first member 81a moves in the + Z direction, the connection member 82 rotates around the fixing pin 84 in the clockwise direction against the restoring force of the elastic member 86. Then, the end of the connection member 82 is moved in the + Y direction by the rotation, so that the entire white plate holding member 81 and the standard white plate 70 are moved in the + Y direction with respect to the image reading unit 26. That is, in conjunction with the movement of the image reading unit 26 in the + Z direction, the standard white plate 70 moves in the + Y direction while maintaining the distance from the light transmission surface 261a at the standard distance d.

  As described above, when the standard white plate 70 is moved in the Y direction, the image reading unit 26 performs the reading operation a plurality of times, whereby a plurality of different positions on the standard white plate 70 can be read. Further, since the distance between the standard white plate 70 and the light transmission surface 261a is maintained at the standard distance d in the plurality of readings, the standard white plate 70 can be appropriately read under the same optical conditions. .

(Modification 3)
Next, a third modification of the above embodiments will be described. This modification can be applied to both the first embodiment and the second embodiment.
This modification is different from the above embodiment in that the position of the surface of the recording medium P placed on the conveyance surface 211a of the conveyance drum 211 is detected and the position of the image reading unit 26 is adjusted based on the detection result. Different. Hereinafter, differences from the above embodiment will be described.

  The detection unit 53 of this modification includes a position detection unit that detects the position in the Z direction of the surface of the recording medium P placed on the transport surface 211a. The position detection unit includes a distance sensor such as a coaxial confocal sensor that measures the distance to the surface of the recording medium P that is attached to the housing 261 of the image reading unit 26 and faces the light transmission surface 261a. Can do.

  In the present modification, the position of the surface of the recording medium P in the Z direction is detected by the position detection unit of the detection unit 53 in step S103 of the image recording process shown in FIG. 6, and the CPU 41 is based on the detection result. Then, the image reading unit 26 is moved to the recording medium reading position. That is, based on the detection result of the surface position of the recording medium P, the CPU 41 controls the image reading unit 26 by the reading position adjustment unit 27 so that the distance between the light transmission surface 261a and the surface of the recording medium P becomes the standard distance d. Move.

  As described above, the image reading apparatus according to the present modification includes the detection unit 53 that detects the position of the surface of the recording medium P placed on the conveyance surface 211a in the Z direction, and the CPU 41 performs the recording medium reading operation. Based on the detected position, the image reading unit is adjusted by the reading position adjusting unit 27 so that the distance in the Z direction between the surface of the recording medium P placed on the conveyance surface 211a and the light transmission surface 261a becomes the standard distance d. 26 is moved (reading control means). According to this, regardless of the thickness of the recording medium P, it is possible to appropriately read the recording medium P under the same optical conditions as when the standard white plate 70 is read.

Note that the present invention is not limited to the above-described embodiments and modifications, and various modifications can be made.
For example, in each of the above-described embodiments and modifications, an example in which the standard white plate 70 is disposed at a position facing the light transmission surface 261a by the operation of the white plate moving unit 29 when the image reading unit 26 is calibrated will be described. However, the standard white plate 70 may be disposed by a white plate moving device separately provided outside the ink jet recording apparatus 1 or by a human hand.

Further, in each of the above embodiments and modifications, in the white plate reading operation, the image reading unit 26 moves the standard white plate 70 in the Y direction and the plurality of lines having different positions in the Y direction on the surface of the standard white plate 70. However, the present invention is not limited to this example. For example, while moving the standard white plate 70 in the X direction, that is, in a direction parallel to the arrangement direction of the imaging elements 265a in the line sensor 265, a plurality of lines having different ranges in the X direction on the surface of the standard white plate 70 are read. May be. When reading is performed in this way, when foreign matter such as dust adheres to the surface of the standard white plate 70, the pixel values of the pixels corresponding to the different imaging elements 265a are obtained in each of the reading results of the plurality of lines. Since the abnormality due to the foreign matter occurs, the adhesion of the foreign matter to the standard white plate 70 can be easily detected.
In the white plate reading operation, the standard white plate 70 may be fixed and the image reading unit 26 may be moved.
Further, in the white plate reading operation, the image reading unit 26 and the standard white plate 70 are not moved relative to each other, and the image reading unit 26 reads only one line on the surface of the standard white plate 70 to generate white plate imaging data. Also good.

  In each of the above-described embodiments and modifications, the surface of the standard white plate 70 moved by the white plate moving unit 29 has been described by using the image reading unit 26. However, the present invention is not limited to this. The reading of the standard white plate 70 by the image reading unit 26 may be performed in a state where the movement operation of the standard white plate 70 by the white plate moving unit 29 is temporarily stopped.

  In each of the above-described embodiments and modifications, the white plate moving unit 29 is used to move the standard white plate 70 in the Y direction, but instead, for example, on the transport surface 211a of the transport drum 211. The standard white plate 70 may be moved in the Y direction by placing the standard white plate 70 and rotating the transport drum 211. In this case, the height of the image reading unit 26 may be adjusted by the reading position adjusting unit 27 so that the distance between the surface of the standard white plate 70 on the conveyance surface 211a and the light transmission surface 261a becomes the standard distance d. .

  In the first embodiment and the modified example, when the surface of the standard white plate 70 is read by the image reading unit 26, the image is set such that the distance between the light transmission surface 261a and the standard white plate 70 is the standard distance d. The example of adjusting the position of the reading unit 26 in the Z direction has been described, but instead, the image reading unit 26 may be fixed and the position of the standard white plate 70 in the Z direction may be adjusted. For example, the position of the standard white plate 70 in the Z direction may be adjusted by moving the transport drum 211 in the Z direction after placing the standard white plate 70 on the transport surface 211a of the transport drum 211.

  In each of the above-described embodiments and modified examples, the recording medium P is transported by the transport drum 211. For example, the recording medium P may be transported by a transport belt (transport member) that is supported by two rollers and moves according to the rotation of the rollers. Further, the recording medium P may be transported by a transport member that reciprocates on the same plane. In these cases, a standard white plate may be placed on the transport member and transported, and a plurality of different lines on the transported standard white plate may be read by the image reading unit 26.

  In each of the above embodiments and modifications, the light incident surface of the image reading unit 26 is described as an example of the light transmitting surface 261a. However, the light incident surface does not necessarily have to be a flat surface. What is necessary is just a part with the fixed area in which the reflected light in the surface injects. Accordingly, the light incident surface may have a shape other than a flat surface such as a curved surface.

  In each of the above-described embodiments and modifications, the test chart 61 has been described as an example of an image on the recording medium P read by the image reading unit 26. However, the image reading unit 26 is not limited to this. The normal image 60 and other test images may be read.

  Further, in each of the above embodiments and modifications, the description has been given using the example in which the control unit 40 generates the calibration image data based on the white plate imaging data and calculates the correction value C (i). At least one may be performed by an information processing apparatus (for example, the external apparatus 2) provided outside the inkjet recording apparatus 1.

  In each of the above-described embodiments and modifications, the example in which the portion corresponding to the image reading device of the inkjet recording apparatus 1 includes the transport unit 21 has been described. However, the image reading device does not include the transport unit 21. May be. For example, in an aspect in which the ink jet recording apparatus and the image reading apparatus are configured separately and the surface of the recording medium P conveyed by the conveyance unit of the ink jet recording apparatus is read by the image reading apparatus, the present invention is applied to the image reading apparatus. May be.

  In each of the above embodiments and modifications, the single-pass inkjet recording apparatus 1 has been described as an example. However, the present invention may be applied to an inkjet recording apparatus that records an image while scanning a head unit. good. Further, the present invention may be applied to an ink jet recording apparatus in which a single nozzle is provided in the head unit.

  In each of the above-described embodiments, the ink jet recording apparatus 1 that heats and discharges ink that is gel-like at room temperature and becomes sol-like when heated is described as an example. Alternatively, various known inks including ink that is sol or liquid at normal temperature may be used.

  In each of the above embodiments and modifications, the piezoelectric inkjet recording apparatus 1 using a piezoelectric element as an image recording apparatus has been described as an example. However, the present invention is not limited to this. For example, a thermal ink jet recording apparatus that discharges ink by generating bubbles in the ink by heating, a dry electrophotographic image recording apparatus that forms an image of toner particles on a photosensitive drum and transfers the image to a recording medium, toner The present invention can be applied to various types of image recording apparatuses such as wet electrophotographic image recording apparatuses that use liquid toner instead of particles.

  Although several embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, and includes the scope of the invention described in the claims and equivalents thereof. .

  The present invention can be used for an image reading apparatus, an image recording apparatus, and a method for controlling the image reading apparatus.

DESCRIPTION OF SYMBOLS 1 Inkjet recording apparatus 2 External apparatus 10 Paper feed part 11 Paper feed tray 12 Medium supply part 20 Image recording part 21 Conveyance part 211 Conveyance drum 211a Conveyance surface 22 Delivery unit 23 Heating part 24 Head unit 241 Recording head drive part 242 Recording head 25 Fixing unit 26 Image reading unit 261 Case 261a Light transmission surface 262 Light source 2631, 2632 Mirror 264 Optical system 265 Line sensor 265a Image sensor 27 Reading position adjustment unit 28 Delivery unit 29 White plate moving unit 291 Arm 292 Rotating shaft 293 Fixed pin 294 Opening 295 White plate holding member 296 Fixing pin 297 Opening 298 Roller 299 Guide member 30 Paper discharge part 31 Paper discharge tray 40 Control part 41 CPU
42 RAM
43 ROM
44 Storage unit 44a Image reading unit calibration data 51 Transport drive unit 52 Operation display unit 53 Detection unit 54 Input / output interface 55 Bus 60 Normal image 61 Test chart 70 Standard white plate 81 White plate holding member 81a First member 81b Second member 82 Connection members 83 and 84 Fixing pin 85 Support member 86 Elastic member P Recording medium

Claims (14)

A reading means for detecting reflected light on the surface of the reading target by an image sensor and reading the surface of the reading target;
A reading control means for causing the reading means to perform a recording medium reading operation for reading the surface of the recording medium and a reference member reading operation for reading the surface of a predetermined reference member;
Imaging data generating means for generating reference member imaging data used for calibration of the reading means related to the detection value of the imaging element based on the detection value of the imaging element in the reference member reading operation;
A moving unit that performs a moving operation of moving at least one of the reading unit and the reference member along an incident axis direction of light incident on the imaging element from the surface of the reading target;
With
In the reference member reading operation, the reading control unit is configured such that a distance in the incident axis direction between the surface of the reference member and the light incident surface of the reading unit is a recording medium when the recording medium reading operation is performed. The moving means performs the moving operation so as to be a standard distance set in advance as a distance in the incident axis direction between the surface and the light incident surface, and the distance from the light incident surface is the standard distance. An image reading apparatus, wherein the reading member is caused to read the reference member at a position.   The image reading apparatus according to claim 1, wherein the moving unit includes a reading unit moving unit that moves the reading unit in the incident axis direction. The moving means includes a reference member moving unit that moves the reference member between a facing position facing the light incident surface and a retracted position deviating from the facing position.
3. The image reading according to claim 2, wherein the reading control unit moves the reference member to the opposed position by the reference member moving unit when the reference member reading operation is performed by the reading unit. apparatus.   The reading unit moving unit and the reference member moving unit are configured so that the movement of the reading unit by the reading unit moving unit and the movement of the reference member by the reference member moving unit can be interlocked. The image reading apparatus according to claim 3. The reading means moving unit moves the reading means between a recording medium reading position when the recording medium reading operation is performed and a reference member reading position when the reference member reading operation is performed,
The reference member moving unit is configured such that when the reading unit is at the recording medium reading position, the reference member is disposed at a predetermined retracted position with respect to the reading unit, and when the reading unit is at the reference member reading position. The reference member is moved so that the reference member is disposed at a predetermined read position with respect to the reading means that faces the light incident surface and the distance between the light incident surface and the reference member is the standard distance. The image reading apparatus according to claim 4, wherein: The reading unit has a line sensor that outputs a one-dimensional image, and reads the reading range extending in a predetermined direction on the surface of the reference member by the line sensor,
The imaging data generation unit is configured to read the reference member from a plurality of reading ranges obtained by reading the plurality of reading ranges according to the movement of the reference member by the reference member moving unit on the surface of the reference member. Imaging data is produced | generated. The image reading apparatus as described in any one of Claims 3-5 characterized by the above-mentioned. A mounting member having a mounting surface on which the recording medium is mounted;
In the recording medium reading operation, the reading control unit performs the reading so that a distance between the surface of the recording medium placed on the mounting surface and the light incident surface in the incident axis direction becomes the standard distance. The reading means is moved by means moving means, and the recording medium at a position where the distance from the light incident surface is the standard distance is read by the reading means. The image reading apparatus according to one item. Thickness information acquisition means for acquiring information related to the thickness of the recording medium,
In the recording medium reading operation, the reading control unit is configured to determine a distance in the incident axis direction between the surface of the recording medium placed on the mounting surface and the light incident surface based on the acquired information. The image reading apparatus according to claim 7, wherein the reading unit is moved by the reading unit moving unit so as to be the standard distance. Comprising a detecting means for detecting a position of the surface of the recording medium placed on the placing surface in the incident axis direction;
In the recording medium reading operation, the reading control unit is configured to determine a distance in the incident axis direction between the surface of the recording medium placed on the mounting surface and the light incident surface based on the detected position. The image reading apparatus according to claim 7, wherein the reading unit is moved by the reading unit moving unit so as to be the standard distance. A transport means for transporting the recording medium placed on the placement surface by moving the placement member;
The image reading apparatus according to claim 7, wherein the reading control unit causes the reading unit to read a recording medium conveyed by the conveying unit in the recording medium reading operation. . The mounting member is a drum,
The transporting means transports the recording medium by rotating the drum along a cylindrical axis of the drum in a state where the recording medium is placed on an outer peripheral curved surface of the drum. The image reading apparatus according to 10.   The image reading apparatus according to claim 1, further comprising a calibration unit configured to perform the calibration based on the reference member imaging data. Recording means for recording an image on a recording medium;
The image reading apparatus according to any one of claims 1 to 12, wherein an image recorded on the recording medium is read by the recording unit;
An image recording apparatus comprising: Reading means for detecting reflected light on the surface of the reading target by the image sensor and reading the surface of the reading target, and light that enters at least one of the reading means and the predetermined reference member from the surface of the reading target to the imaging element A moving unit that performs a moving operation of moving along the incident axis direction of the image reading apparatus,
A recording medium reading step for reading the surface of the recording medium by the reading means;
A reference member reading step for causing the reading means to read the surface of the reference member;
An imaging data generation step for generating reference member imaging data used for calibration of the reading unit related to the detection value of the imaging element based on the detection value of the imaging element in the reference member reading step;
Including
In the reference member reading step, the distance in the incident axis direction between the surface of the reference member and the light incident surface of the reading means is the surface of the recording medium and the light incident surface when the recording medium reading step is performed. The moving means performs the moving operation so that a standard distance set in advance as a distance in the incident axis direction with respect to the incident axis direction, and the reference is located at a position where the distance from the light incident surface is the standard distance. A method for controlling an image reading apparatus, comprising: reading a member by the reading unit.

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