JP2018176445A - Ink jet recording apparatus and failure detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording apparatus and a failure detection method, enabling an ink curing failure to be detected more securely.SOLUTION: The ink jet recording apparatus comprises: an ink ejection part that ejects, from a nozzle, ink which cures by predetermined energy line; an energy-line irradiation part that performs an irradiation operation in which the ink ejected by the ink ejection part and arrived at a recording medium is cured by being irradiated with the energy line; reading control means that causes reading means to perform a first reading operation in which the surface of the recording medium is read after the ink is ejected on the recording medium by the ink ejection part and before the irradiation operation for the ink on the recording medium, and a second reading operation in which the surface of the recording medium after the irradiation operation is read; and curing-failure detection means detecting curing failure of the ink on the recording medium on the basis of a result of reading through the first reading operation and a result of reading through the second reading operation.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an inkjet recording apparatus and a defect detection method.

  2. Description of the Related Art Conventionally, there is an inkjet recording apparatus that records an image on a recording medium by discharging ink from the nozzles onto the recording medium and causing the ink to land in a desired pattern. In the ink jet recording apparatus, the ink which is cured by a predetermined energy beam is discharged from a nozzle, and the ink on the recording medium which has been discharged is irradiated with the predetermined energy beam to cure the ink, thereby causing the ink on the recording medium. There is something to fix.

  In such an inkjet recording apparatus, when the irradiation amount of energy rays is insufficient, curing failure in which the curing of the ink is insufficient occurs and fixing failure of the ink accompanying the curing failure occurs. Poor fixing of the ink causes an abnormality in the gloss and color of the recorded image by the ink jet recording apparatus, leading to the deterioration of the image quality of the recorded image. The presence or absence of image quality deterioration in the recorded image can be detected by providing a reading means for reading the surface of the recording medium after the ink is cured (for example, Patent Document 1) and analyzing the reading result by this reading means .

JP, 2015-016627, A

  However, the image quality defect of the recorded image can be caused not only by the curing defect of the ink but also by the ink discharge defect such as the abnormality of the ejected ink amount from the nozzle and the abnormality of the landing position of the ink. For this reason, in the above-described conventional technology, there is a problem that it is not possible to reliably detect whether or not curing failure of the ink occurs in the recorded image based on the reading result of the recorded image.

  An object of the present invention is to provide an ink jet recording apparatus and a defect detection method capable of more reliably detecting the curing failure of the ink.

In order to achieve the above object, the invention of an ink jet recording apparatus according to claim 1 is:
An ink discharge unit that discharges an ink which is cured by a predetermined energy beam from a nozzle;
An energy ray irradiation unit performing an irradiation operation of curing the ink by irradiating the ink on the recording medium discharged by the ink discharge unit with the predetermined energy ray;
Reading means for reading the surface of the recording medium;
A first reading operation for reading the surface of the recording medium after the ink is ejected by the ink discharge unit onto the recording medium and before the irradiation operation for the ink on the recording medium is performed, and the ink for the ink Reading control means for causing the reading means to perform a second reading operation for reading the surface of the recording medium after the irradiation operation has been performed;
Curing failure detecting means for detecting curing failure of the ink on the recording medium based on the reading result by the first reading operation and the reading result by the second reading operation;
It is characterized by having.

The invention according to claim 2 is the inkjet recording apparatus according to claim 1,
It further comprises conveying means for conveying the recording medium along a path passing through the landing range of the ink ejected by the ink ejection unit, the irradiation range of the predetermined energy beam by the energy ray irradiation unit, and the reading range by the reading unit. It is characterized.

The invention described in claim 3 is the ink jet recording apparatus according to claim 2.
The reading means is
The surface of the recording medium conveyed by the conveyance means is a first side of the ink impacting area downstream of the ink impacting area in the conveyance direction of the recording medium by the conveyance means and upstream of the predetermined energy beam irradiation area. A first imaging unit for imaging in the imaging range of
A second imaging unit configured to image the surface of the recording medium conveyed by the conveyance means in a predetermined second imaging range on the downstream side of the irradiation range of the predetermined energy beam in the conveyance direction;
Have
The reading control means reads the first reading operation to read by imaging the surface of the recording medium by the first imaging unit, and reads the image by imaging the surface of the recording medium by the second imaging unit. It is characterized in that the second reading operation is performed by the reading means.

The invention according to a fourth aspect is the inkjet recording apparatus according to the third aspect, wherein
The transport means is
Moving the recording medium in the conveyance direction by moving the conveyance members while transferring the recording medium to be conveyed between the plurality of conveyance members on which the recording medium is placed;
The recording medium placed on the first transport member of the plurality of transport members is moved along a path passing through the landing area of the ink by the movement operation of the first transport member.
The recording medium moved by the first conveyance member is placed on the second conveyance member of the plurality of conveyance members, and irradiation of the predetermined energy beam is performed by the movement operation of the second conveyance member. It is characterized by moving along a route passing through the range.

The invention described in claim 5 is the ink jet recording apparatus according to claim 4.
The transport means moves the recording medium placed on the first transport member along a path sequentially passing through the landing range of the ink and the first imaging range by the movement operation of the first transport member. It is characterized by

The invention according to claim 6 is the inkjet recording apparatus according to claim 4 or 5.
The transport means places the recording medium moved by the second transport member on a third transport member of the plurality of transport members, and the moving operation of the third transport member It is characterized in that it is moved along a path passing through the two imaging ranges.

The invention according to claim 7 is the ink jet recording apparatus according to any one of claims 1 to 6.
Recording control means for causing the ink discharge unit to discharge the ink from the nozzle to the recording medium and recording a test image including a defect detection pattern of a predetermined density on the recording medium;
The reading control means causes the reading means to perform the first reading operation and the second reading operation on the recording medium on which the test image is recorded.
The curing failure detection means is a first reference range in which the intensity of incident light from each position of the failure detection pattern relates to the detection of the ink discharge failure from the nozzle based on the reading result by the first reading operation. A second reference range in which the intensity of incident light from at least a part of the defect detection pattern is based on the detection result of the ink based on the reading result by the second reading operation. It is characterized in that, when it is judged that the inside is not inside, it is judged that there is the curing failure.

According to an eighth aspect of the present invention, in the inkjet recording apparatus according to any one of the first to sixth aspects,
A test image including a defect detection pattern for causing the ink ejection unit to eject ink onto the recording medium from the nozzle and detecting an ink ejection failure from the nozzle of the ink ejection unit is recorded on the recording medium. Recording control means to
The reading control means causes the reading means to perform the first reading operation and the second reading operation on the recording medium on which the test image is recorded.
The curing failure detection unit detects the ink discharge failure based on the reading result by the first reading operation, and the curing failure is based on the detection result of the ink discharging failure and the reading result by the second reading operation. It is characterized by detecting

The invention according to claim 9 is the inkjet recording apparatus according to any one of claims 3 to 6,
A test image including a defect detection pattern for causing the ink ejection unit to eject ink onto the recording medium from the nozzle and detecting an ink ejection failure from the nozzle of the ink ejection unit is recorded on the recording medium. Recording control means to
The imaging characteristic of the first imaging unit and the imaging characteristic of the second imaging unit are different from each other
The reading control means causes the reading means to perform the first reading operation and the second reading operation on the recording medium on which the test image is recorded.
The curing failure detection unit detects the ink discharge failure based on the reading result by the first reading operation, and the curing failure is based on the detection result of the ink discharging failure and the reading result by the second reading operation. It is characterized by detecting

The invention according to claim 10 is the inkjet recording apparatus according to claim 9.
The imaging resolution by the first imaging unit is characterized by being higher than the imaging resolution by the second imaging unit.

The invention according to claim 11 is the inkjet recording apparatus according to claim 9 or 10, wherein
The first imaging unit detects incident light from the surface of the recording medium with one spectral sensitivity characteristic to image the surface of the recording medium, and the second imaging unit has a plurality of different spectral sensitivity characteristics. The present invention is characterized in that the incident light from the surface of the recording medium is detected to pick up an image of the surface of the recording medium.

The invention according to claim 12 is the inkjet recording apparatus according to any one of claims 9 to 11,
The recording control unit causes the ink discharge unit to perform the discharge operation of discharging the ink from the nozzles a plurality of times at predetermined discharge time intervals with respect to the recording medium being conveyed at a predetermined speed by the conveyance unit. Record the test image with
The reading control means causes the first imaging unit to image the surface of the recording medium being conveyed at the predetermined speed by the conveying means a plurality of times at the same time interval as the ejection time interval, and the plurality of times Each of the imaging operations is characterized in that the first imaging unit causes the first imaging unit to image a range in which the ink ejected onto the recording medium has landed in the one ejection operation.

In order to achieve the above object, the invention of the defect detection method according to claim 13 is:
An ink ejection unit that ejects an ink that is cured by a predetermined energy beam from a nozzle, and an irradiation that cures the ink by irradiating the ink on the recording medium ejected by the ink ejection unit with the predetermined energy beam An ink jet recording apparatus comprising: an energy beam irradiating unit for performing operation; and a reading unit for reading a surface of the recording medium, wherein the method is a defect detection method for detecting a curing failure of ink on the recording medium,
A first reading operation for reading the surface of the recording medium after the ink is ejected by the ink discharge unit onto the recording medium and before the irradiation operation for the ink on the recording medium is performed, and the ink for the ink A reading step of causing the reading means to perform a second reading operation for reading the surface of the recording medium after the irradiation operation has been performed;
A curing failure detection step of detecting curing failure of the ink on the recording medium based on the reading result by the first reading operation and the reading result by the second reading operation;
It is characterized by including.

  According to the present invention, there is an effect that the curing failure of the ink can be detected more reliably.

FIG. 1 is a view showing a schematic configuration of an inkjet recording apparatus. It is a schematic diagram which shows the structure of a head unit. FIG. 2 is a block diagram showing the main functional configuration of the inkjet recording apparatus. It is a figure explaining the influence which the curing defect of an ink gives to an image quality. It is a flowchart which shows the control procedure of a hardening defect detection process. It is a figure which shows the example of the discharge defect detection pattern contained in a test image. It is a flowchart which shows the control procedure of the hardening defect detection process which concerns on 2nd Embodiment. It is a figure which shows schematic structure of the inkjet recording device which concerns on 3rd Embodiment.

  Hereinafter, embodiments of the inkjet recording apparatus and the defect detection method of the present invention will be described based on the drawings.

First Embodiment
FIG. 1 is a view showing a schematic configuration of an inkjet recording apparatus 1 according to a first embodiment of the present invention.
The inkjet recording apparatus 1 includes a recording medium supply unit 10, a recording medium heating unit 20, an image recording and reading unit 30, a fixing unit 40, an image reading unit 50, a recording medium discharge unit 60, and a control unit 70 (recording unit Control means, reading control means, curing failure detection means) (FIG. 3) and the like are provided.

The recording medium supply unit 10 includes a placement tray 11, a medium delivery roller 12, and the like.
The placement tray 11 is a plate-like member on which various individual recording media P such as sheet, cardboard, corrugated board material and resin plate can be stacked and placed, and from the recording medium P placed at the top, It is sent to the recording medium heating unit 20 in order. The placement tray 11 is movable in the vertical direction, and is held at a position where the uppermost recording medium P is delivered to the recording medium heating unit 20 according to the total weight of the placed recording medium P and the like.
The medium delivery roller 12 is a rotatable roller that holds the recording medium P from above and below, and delivers the recording medium P placed on the top of the placement tray 11 in the horizontal direction here. The medium delivery roller 12 is attached with a guide member for aligning the recording medium P at a predetermined position in the width direction perpendicular to the conveyance direction (left direction in FIG. 1) of the recording medium P. The recording medium P is sent to the recording medium heating unit 20 in a state in which the direction alignment is performed.

  The recording medium heating unit 20 includes a plurality of heating rollers 21. The plurality of heating rollers 21 heats while conveying the recording medium P by rotating in a state where the recording medium P is sandwiched from both sides. The plurality of heating rollers 21 is provided with a core-shaped heater 811 (FIG. 3), and the surface of the heating roller 21 is heated by the heaters 811 to transfer heat to the recording medium P, thereby the recording medium P is obtained. Heat up.

The image recording and reading unit 30 is provided on the downstream side of the recording medium heating unit 20 with respect to the conveyance direction of the recording medium P. The image recording / reading unit 30 ejects ink on the recording medium P delivered from the recording medium heating unit 20 to record an image, and picks up an image of the surface of the recording medium P after the ink is ejected (read ) The imaging data (reading result) is output to the control unit 70. Further, the image recording and reading unit 30 sends the recording medium P having the ink ejected from the head unit 34 to the fixing unit 40.
The image recording / reading unit 30 includes one or more of a conveyance unit 31 having a conveyance belt 311 (first conveyance member), a drive roller 312 and a driven roller 313, a support suction unit 32, a pressure roller 33, and ink. (Here, four) head units 34 (ink discharge units), a first imaging unit 35, and the like.

  The conveyance belt 311 of the conveyance unit 31 is an endless (annular) belt-like member that is stretched around the driving roller 312 and the driven roller 313, and a steel belt is used here. In the conveyance belt 311, the drive roller 312 is driven by the conveyance motor 861 (FIG. 3) attached to the drive roller 312 to rotate, thereby rotating the drive roller 312 and the driven roller 313 according to the rotation operation. Travel around the circuit. The conveyance unit 31 moves the recording medium P placed on the conveyance belt 311 by the circulation movement operation of the conveyance belt 311, so that the ink impact range by the head unit 34 and the first imaging unit 35 by the first imaging unit 35. The imaging range (reading range) is sequentially passed at a predetermined transport speed.

  The support suction unit 32 is provided along the inner circumferential surface of the conveyance belt 311, and supports the conveyance belt 311 which slides on the support suction unit 32 and circulates in a plane. In addition, the support suction unit 32 sucks air by a suction fan 821 (FIG. 3) from the side opposite to the mounting surface side of the conveyance belt 311, that is, the inner circumferential surface side via a hole provided in the conveyance belt 311. By doing this, the recording medium P on the conveyance belt 311 is adsorbed onto the outer peripheral surface (the mounting surface of the recording medium P) of the conveyance belt 311.

  The pressure roller 33 is a roller rotatably provided at a position facing the driven roller 313 with the conveyance belt 311 interposed therebetween, and from the mounting surface of the conveyance belt 311 of the recording medium P delivered from the recording medium heating unit 20 In particular, the sheet is pressed (pressed) against the conveying belt 311 with an appropriate pressure to suppress the curling (rolling up) of the front end portion and the like, and guided along the conveying belt 311 Do.

  The head unit 34 receives the recording medium from the nozzle opening provided on the ink ejection surface facing the placement surface of the conveyance belt 311 at an appropriate timing according to the circumferential movement of the conveyance belt 311 on which the recording medium P is placed. An image is recorded by performing a recording operation for discharging ink to P. The head unit 34 is disposed such that the ink ejection surface and the placement surface are separated by a predetermined distance. In the inkjet recording apparatus 1 of the present embodiment, four head units 34 respectively corresponding to four color inks of yellow (Y), magenta (M), cyan (C), and black (K) are in the conveyance direction of the recording medium P. From the upstream side, they are arranged in the order of Y, M, C, and K in a predetermined interval. Alternatively, the image recording / reading unit 30 may be equipped with a head unit 34 for discharging ink other than these four colors, for example, ink of each color such as orange, green, violet, red, blue, white, transparent ink, etc. .

FIG. 2 is a schematic view showing the configuration of the head unit 34. As shown in FIG. FIG. 2 is a plan view of the entire head unit 34 as viewed from the side facing the mounting surface of the transport belt 311.
In the present embodiment, the head unit 34 includes sixteen recording heads 341 in which a plurality of recording elements that eject ink are arranged in the width direction. The recording element communicates with a pressure chamber (channel) for storing ink, a piezoelectric element provided on the wall of the pressure chamber, an electrode for applying a voltage to the piezoelectric element to generate an electric field, and the pressure chamber. And a nozzle 343 for discharging the ink in the pressure chamber. When a voltage signal of a drive waveform that causes the piezoelectric element to deform is applied to the electrode of the recording element, the pressure chamber is deformed according to the voltage signal, the pressure in the pressure chamber changes, and the pressure changes according to the change in the pressure Ink is discharged from a nozzle 343 communicating with the pressure chamber. The nozzle 343 discharges an amount of ink according to the opening area of the nozzle 343 and the drive signal.
The arrangement direction of the recording elements in each recording head 341 is not limited to the width direction, and may be a direction intersecting the transport direction at an angle other than right angle.

In the head unit 34, two recording heads 341 are combined two by two, and eight head modules 342 configured by the combination of the recording heads 341 are provided. In each head module 342, the recording heads 341 are arranged in such a positional relationship that the nozzles 343 of the recording elements of the two recording heads 341 are alternately arranged in the width direction. The eight head modules 342 are arranged in a staggered pattern so that the arrangement ranges of the recording elements in the width direction partially overlap with each other to configure a line head.
The arrangement range of the recording elements included in the head unit 34 in the width direction covers the recordable width of the image in the width direction of the recording medium P conveyed by the conveyance unit 31. The position of the head unit 34 is fixed at the time of recording an image, and the ink is discharged at predetermined intervals (intervals in the transport direction) at different positions in the transport direction according to the transport of the recording medium P. Record images by single pass method. More specifically, in the image recording operation on the recording medium P by the head unit 34, the transport position of the recording medium P has reached a predetermined image recording start position by a pulse signal from a rotary encoder (not shown) attached to the drive roller 312 It is started at the timing indicated. Further, after the start of the recording operation, the ink discharge by the recording element at each position in the transport direction on the recording medium P is an ejection start pulse generated for each predetermined count number of clock pulses by the head control unit 83 (FIG. 3). It is performed at the timing when it is input to the recording head 341. That is, in the head unit 34, an image is recorded by repeatedly performing the discharge operation of discharging the ink from the nozzles 343 at a predetermined discharge time interval on the recording medium P conveyed at a predetermined conveyance speed. .
The configuration of the head unit 34 is not limited to the above. For example, instead of the head module 342, the recording heads 341 may be arranged in a staggered pattern, and the head unit 34 may be a single recording head 341. It may be set as having composition.

  In the head unit 34, an ink discharge failure may occur which is at least one of a failure in the amount of ink discharged from the nozzle 343 and a failure in the landing position on the recording medium P of the ink discharged from the nozzle 343. An ink discharge failure may occur due to a nozzle failure such as a processing variation at the time of forming a nozzle, a characteristic variation of the piezoelectric element, a clogging of the nozzle 343, or an obstruction caused by adhesion of foreign matter to the opening of the nozzle 343. In addition to the above-mentioned nozzle failure, the ink ejection failure related to the landing position of the ink can also occur due to an error in the mounting position of the head module 342 or the recording head 341 in the head unit 34. When the recording operation is performed by the head unit 34 when there is an ink discharge failure, gloss unevenness and color unevenness (density unevenness) occur in the recorded image, which leads to the deterioration of the image quality.

As the ink ejected from the nozzle 343 of the recording element, one having a property of being phase-changed into gel or sol depending on temperature and being cured by irradiation of energy rays such as ultraviolet rays is used. As the ink, those containing a photopolymerizable compound (monomer), a photopolymerization initiator, a gelling agent and a colorant are used. Among these, the photopolymerizable compound is a compound which is polymerized by the progress of a polymerization reaction when irradiated with ultraviolet light. The polymerization of the monomer cures the ink.
In the present embodiment, an ink which is gelled at normal temperature and which becomes sol when heated is used. The head unit 34 includes an ink heating unit (not shown) that heats the ink stored in the head unit 34. The ink heating unit operates under the control of the control unit 70, and the ink is heated to a sol temperature Heat up. The recording head 341 discharges the ink which has been heated to form a sol. When the sol-like ink is discharged onto the recording medium P, the ink droplets land on the recording medium P and then naturally cooled, whereby the ink becomes gelled quickly and solidifies on the recording medium P.

  The first imaging unit 35 is provided on the downstream side of the head unit 34 in the transport direction, and is arranged to be capable of imaging the surface of the recording medium P on the placement surface of the transport belt 311. The imaging unit 35 includes a line sensor having a plurality of imaging elements arranged in the width direction, and pixel data of imaging pixels arranged one-dimensionally in the imaging range across the recordable width in the width direction by the line sensor. The one-dimensional imaging data consisting of the above are acquired and output to the control unit 70. The detection value in the pixel data of the imaging pixel represents the intensity of the incident light reflected on the surface of the recording medium P. Therefore, the intensity distribution of incident light on the surface of the recording medium P can be acquired from the imaging data generated by the first imaging unit 35.

The line sensor of the first imaging unit 35 outputs a one-dimensional image using a plurality of imaging elements arranged in the width direction, each outputting a signal corresponding to the intensity of incident light. Each imaging device has three sub imaging devices each for detecting the spectral intensity of incident light with spectral sensitivity characteristics respectively corresponding to R (red), G (green) and B (blue). Thus, the first imaging unit performs imaging (imaging in a plurality of colors) for the three color components of R, G, and B. Each sub-imaging element transmits, for example, light of R, G, or B wavelength component to the light receiving portion of a charge coupled device (CCD) sensor or a complementary metal oxide semiconductor (CMOS) sensor including a photodiode as a photoelectric conversion element. It is possible to use one in which a color filter is disposed. Alternatively, each secondary imaging device uses a sensor whose spectral sensitivity characteristic corresponds to R, G or B, and the spectral intensity of incident light with a spectral sensitivity characteristic corresponding to R, G or B without passing through a color filter May be detected. The signal output from the line sensor is subjected to current-voltage conversion, amplification, noise removal, analog-to-digital conversion, etc. in an analog front end (not shown), and output to the control unit 70 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 device in 256 gradations from 0 to 255.
One-dimensional imaging with respect to each position in the transport direction on the recording medium P by the first imaging unit 35 is performed at timing according to the imaging start pulse synchronized with the above-described ejection start pulse. That is, the imaging by the first imaging unit 35 is performed at timing synchronized with the ink ejection timing from the nozzle 343 by the head unit 34. More specifically, in the first imaging unit 35, one-dimensional imaging is repeatedly performed a plurality of times at the same imaging time interval as the above-described ejection time interval in which the head unit 34 performs the plurality of ink ejection operations. In each of the plurality of imaging operations, the range in which the ink ejected onto the recording medium P has landed in one ejection operation of the head unit 34 is imaged.

The fixing unit 40 is provided on the downstream side of the image recording and reading unit 30 in the transport direction of the recording medium P, and cures and fixes the ink on the recording medium P delivered from the image recording and reading unit 30. The fixing unit 40 includes a conveyance unit 41 having a conveyance belt 411 (second conveyance member), a driving roller 412, and a driven roller 413, a support suction unit 42, a pressing roller 43, and an ultraviolet irradiation unit 44 (energy ray irradiation unit ) Etc. The conveyance unit 41, the support suction unit 42, and the pressure roller 43 can have the same configuration as the conveyance unit 31, the support suction unit 32, and the pressure roller 33 of the image recording and reading unit 30, respectively. In the fixing unit 40, the conveyance unit 41 moves the recording medium P by the circulation movement operation of the conveyance belt 411 to pass the irradiation range of the ultraviolet light by the ultraviolet irradiation unit 44.
The ultraviolet irradiation unit 44 irradiates the recording medium P, which is adsorbed on the mounting surface of the conveyance belt 411 by the support suction unit 42 and conveyed, in a range covering the width of the recording medium P in the width direction. Perform the curing operation. The ink on the recording medium P is cured by this irradiation operation and fixed on the recording medium P.

The image reading unit 50 is provided downstream of the fixing unit 40 in the conveyance direction of the recording medium P, and picks up (reads) image data (reading result) by imaging (reading) the surface of the recording medium P delivered from the fixing unit 40. It outputs to the control unit 70. The image reading unit 50 includes a conveyance unit 51 having a conveyance belt 511 (third conveyance member), a driving roller 512, and a driven roller 513, a support suction unit 52, a pressing roller 53, a second imaging unit 55, and the like. Prepare. The conveyance unit 51, the support suction unit 52, and the pressure roller 53 can have the same configuration as the conveyance unit 31, the support suction unit 32, and the pressure roller 33 of the image recording and reading unit 30, respectively. Further, in the present embodiment, as the second imaging unit 55, one having the same configuration as that of the first imaging unit 35 is used. In the image reading unit 50, the conveyance unit 51 moves the recording medium P by the circulation movement operation of the conveyance belt 511 to pass the second imaging range (reading range) by the second imaging unit 55. In the present embodiment, the first imaging unit 35 and the second imaging unit 55 constitute a reading unit. Further, the transport units 31, 41 and 51 constitute a transport means.
The second imaging unit 55 images the recording medium P on the surface of which the ink is fixed by the fixing unit 40.

  The recording medium discharge unit 60 holds and holds the recording medium P delivered from the image reading unit 50 until it is taken out by the user. The recording medium discharge unit 60 includes a discharge tray 61 and a guide roller 62, holds the recording medium P sent from the image reading unit 50 from above and below by the guide roller 62, conveys the recording medium P, and places the recording medium P on the discharge tray 61.

FIG. 3 is a block diagram showing the main functional configuration of the inkjet recording apparatus 1.
The inkjet recording apparatus 1 includes a control unit 70, a medium heating control unit 81, a heater 811, support suction units 32, 42 and 52 each having a suction control unit 82 and a suction fan 821, a head control unit 83 and a recording head 341. The head unit 34 having the above-described structure, the ultraviolet irradiation control unit 84, the ultraviolet irradiation unit 44, the reading control unit 85, the first imaging unit 35, the second imaging unit 55, the conveyance control unit 86, and the conveyance motor 86, an input / output interface 87, a bus 88 and the like. Among the components, the medium heating control unit 81, the suction control unit 82, the head control unit 83, the ultraviolet irradiation control unit 84, the reading control unit 85, and the transport control unit 86 may use the hardware configurations of the control unit 70 together. A dedicated CPU, memory, logic circuit, etc. may be prepared separately.

  The control unit 70 includes a CPU 71 (Central Processing Unit), a RAM 72 (Random Access Memory), a ROM 73 (Read Only Memory), and a storage unit 74.

  The CPU 71 reads various control programs and setting data stored in the ROM 73, stores them in the RAM 72, and executes the programs to perform various arithmetic processing. Further, the CPU 71 generally controls the overall operation of the inkjet recording apparatus 1.

  The RAM 72 provides the CPU 71 with a working memory space, and stores temporary data. The RAM 72 may include non-volatile memory.

  The ROM 73 stores various control programs executed by the CPU 71, setting data, and the like. Note that instead of the ROM 73, a rewritable non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used.

  The storage unit 74 includes a print job (image recording instruction) input from the external device 2 through the input / output interface 87 and image data of an image to be recorded according to the print job, and the first image pickup unit 35 The second imaging data by the second imaging unit 55 and the like are stored. For example, a hard disk drive (HDD) may be used as the storage unit 74, and a dynamic random access memory (DRAM) may be used in combination.

  The medium heating control unit 81 operates the heater 811 according to the control signal from the control unit 70, and the heater 811 causes the recording medium P to pass through the surface of the heating roller 21 so that the temperature of the recording medium P becomes appropriate. Heat P.

  The suction control unit 82 rotates the suction fan 821 of the support suction units 32, 42 and 52 at a rotation speed according to the control signal from the control unit 70.

  The head control unit 83 outputs the above-described discharge start pulse and image data to the head drive unit in the recording head 341 according to a control signal from the control unit 70, so that the discharge start pulse from the nozzle 343 of the recording head 341 The ink is ejected at an appropriate timing according to.

  The ultraviolet irradiation control unit 84 causes the ultraviolet irradiation unit 44 to emit ultraviolet light in accordance with the control signal from the control unit 70 to perform the above-described irradiation operation.

  The reading control unit 85 controls the operations of the first imaging unit 35 and the second imaging unit 55 to perform imaging of an appropriate position according to the transport timing and speed of the recording medium P. Further, the reading control unit outputs an imaging start pulse synchronized with the above-described ejection start pulse to the first imaging unit 35, thereby synchronizing the ink ejection timing in the head unit 34 with the recording medium P. One-dimensional imaging is performed for each position in the transport direction of.

  The transport control unit 86 operates the transport motor 861 attached to the medium delivery roller 12, the drive rollers 312, 412, 512, the heating roller 21, and the guide roller 62 based on the control signal supplied from the control unit 70. Separately, each roller is rotated to convey the recording medium P at an appropriate speed.

  The input / output interface 87 mediates transmission and reception of data between the external device 2 and the control unit 70. The input / output interface 87 is composed of, for example, various serial interfaces, any of various parallel interfaces, or a combination thereof.

  The bus 88 is a path for transmitting and receiving signals between the control unit 70 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 70 via the input / output interface 87.

Next, the operation of detecting the curing failure of the ink in the inkjet recording apparatus 1 will be described.
In the inkjet recording apparatus 1, when the irradiation amount of the ultraviolet light by the ultraviolet irradiation unit 44 is insufficient in a part of the irradiation range or over the entire irradiation range, the curing of the ink is partially or entirely insufficient. Poor curing occurs, and this leads to poor fixing of the ink. Where there is curing failure of the ink, the surface shape of the ink is different from the location where curing was properly performed. Where there is curing failure of the ink, the surface shape of the ink is different from the location where curing was properly performed. For this reason, the curing failure of the ink causes an abnormality such as unevenness in the gloss and color (density) of the recorded image by the ink jet recording apparatus, leading to the deterioration of the image quality of the recorded image.
On the other hand, in the inkjet recording apparatus 1 according to the present embodiment, the ink of the image recorded on the recording medium P by the head unit 34 is picked up based on the imaging data by the first imaging unit 35 and the second imaging unit 55. Poor curing can be detected.

First, a mechanism for causing image quality defects due to poor curing of the ink will be described.
FIG. 4 is a view for explaining the influence of the poor curing of the ink on the image quality.
FIG. 4A is a view showing a cross section of the ink Ia before curing which has landed on the recording medium P from the nozzle 343. As shown in FIG. As shown in FIG. 4A, the ink Ia before curing has a contact angle determined by the surface tension of each of the ink Ia and the recording medium P, and has a raised shape on the recording medium P. In this state, light incident on the surface of the ink Ia is reflected and diffused in a wide angle range according to the angle of the ink surface at the incident position.
When ultraviolet light is irradiated to the ink Ia by the ultraviolet light irradiation unit 44 and curing proceeds, curing shrinkage occurs due to a change in chemical bonding distance and the like, and the volume of the ink decreases as shown in FIG. Flatten. The light incident on the surface of such a flat ink Ib is reflected at a narrower angle range than the reflected light in the ink Ia, and diffusion is relatively less. For this reason, the recorded image after curing of the ink has a higher gloss than before curing of the ink.

If there is curing failure of the ink, since the ink Ia in the state of FIG. 4A and the ink Ib in the state of FIG. 4B are mixed in the recording medium P, it is visually recognized as gloss unevenness in the recorded image. Ru. In addition, even if the ink is the same, it is recognized as a different color by changing the ratio of the specularly reflected light of the incident light and the diffused light of the ink surface if the diffusion state of the incident light on the surface is different. Therefore, it is visually recognized as color unevenness (density unevenness). In addition, if there is curing failure of the ink throughout the entire recorded image, the gloss and color will be abnormal across the entire recorded image.
The gloss of the ink on the recording medium P is determined by irradiating light from a direction inclined at a predetermined incident angle (for example, 45 degrees) with respect to the direction perpendicular to the recording medium P, and reflecting light (incident light) on the ink surface. The intensity can be measured from the detection value detected in the direction perpendicular to the recording medium P. In such detection, the smaller the gloss (that is, the larger the diffusion on the ink surface), the larger the detected value.

In the inkjet recording apparatus 1 according to the present embodiment, the recording medium P is irradiated with light by the first imaging unit 35 and the second imaging unit 55 at an incident angle of 45 degrees, and imaging in a direction perpendicular to the recording medium P is performed. To be done. Thus, the gloss of the ink on the recording medium P can be detected based on the imaging data of each of the first imaging unit 35 and the second imaging unit 55.
Among them, the first imaging unit 35 is a recording medium after the ink is ejected by the head unit 34 onto the recording medium P and before the irradiation operation by the ultraviolet irradiation unit 44 on the ink on the recording medium P is performed. A first imaging operation (first reading operation) for imaging the surface of P is performed. Therefore, the gloss of the ink before curing can be detected based on the imaging data by the first imaging operation.
Further, the second imaging unit 55 performs a second imaging operation (second operation) for imaging the surface of the recording medium P after the irradiation operation by the ultraviolet irradiation unit 44 is performed on the ink on the recording medium P. Perform reading operation). Therefore, the gloss of the ink after curing can be detected based on the imaging data by the second imaging operation.

  When the ink jet recording apparatus 1 according to the present embodiment detects a curing failure of ink, a predetermined test image is recorded by the head unit 34, and a test image before ink curing is imaged by the first imaging unit 35. After the imaging data (reading result) of 1 is acquired, the test image after ink curing is imaged by the second imaging unit 55, and the second imaging data (reading result) is acquired. Here, the test image is an image in which color unevenness can be easily determined, and in this case, an image including a solid pattern (defect detection pattern) of mid-gradation of a predetermined density.

When the first and second imaging data of the test image are acquired, whether or not the detection value (pixel value) of each pixel data of the second imaging data is a value within a predetermined second reference range Is determined. Here, the second reference range is the imaging data when the second imaging unit 55 captures a test image recorded by the proper ink ejection by the head unit 34 and the proper irradiation operation by the ultraviolet irradiation unit 44. Within the range of detection values in the above, it is as wide as possible. Therefore, when the detected value of the second imaging data is within the second reference range, it is indicated that there are no various defects including curing failure and ink discharge failure.
When at least a part of the detection value in the second imaging data is not within the second reference range, it is determined that uneven gloss or uneven color occurs in the test image after ink curing. Therefore, it is determined that there is a possibility that the curing failure of the ink has occurred on the recording medium P.

  As described above, when at least part of the detection value in the second imaging data is not within the second reference range, the detection value (pixel value) of each pixel data of the first imaging data of the test image is further predetermined. It is determined whether the value is within the first reference range of Here, the first reference range can be within the range of detection values in imaging data when the first imaging unit 35 captures a test image before ink curing that is recorded by the proper ink ejection by the head unit 34. It is as wide as possible. Therefore, when the detection value of the first imaging data is within the first reference range, it is indicated that the image before curing of the ink is free from various recording failures such as ink discharge failure.

When each detected value of the first imaging data falls within the first reference range, unevenness in gloss or color does not occur in the test image before ink curing, that is, ink ejection in recording of the test image It is determined that it was appropriate. Therefore, in this case, the uneven gloss or uneven color after curing of the ink determined based on the second imaging data is caused in the process of curing the ink and is due to the curing failure of the ink. It is determined that
On the other hand, when at least a part of the detection value in the first imaging data is not within the first reference range, it is indicated that gloss unevenness and color unevenness occur in the test image before ink curing. Such gloss unevenness and color unevenness before ink curing may occur due to recording defects such as defects in the amount of ejected ink by the head unit 34 and the landing position of the ink, and abnormalities in the temperature of the ejected ink and the recording medium P. That is, in this case, uneven gloss or uneven color after curing of the ink determined based on the second imaging data may be caused by the recording failure before curing of the ink. . Therefore, in this case, a predetermined recording failure handling operation for the recording failure is performed.
As the recording failure coping operation, for example, detection of ink discharge failure using a predetermined test chart, adjustment of the operation of the recording element according to the detection result, position adjustment of the recording head 341, ink temperature in the head unit 34 Adjustment of the heating temperature of the recording medium P is performed.

  As described above, in the present embodiment, based on the intensity distribution of incident light before and after ink curing indicated by the imaging data of the test image by the first imaging unit 35 and the second imaging unit 55, the image quality of the recorded image is reduced. Since it is possible to distinguish whether the cause is the curing failure of the ink or the printing failure such as the ink discharge failure, the curing failure of the ink can be detected with certainty.

  Subsequently, a control procedure by the control unit 70 of the curing failure detection process executed by the inkjet recording apparatus 1 will be described.

FIG. 5 is a flowchart showing a control procedure of the curing failure detection process.
Prior to the start of the curing failure detection process, the control unit 70 causes the conveyance control unit 86 to output a control signal to the conveyance motor 861 to cause the conveyance belts 311, 411, and 511 to rotate in conveyance units 31, 41 and 51, and The operation for delivering the recording medium P is started between the transport units 31, 41 and 51. Further, the control unit 70 causes the medium heating control unit 81 to output a control signal to the heater 811 to start the heating operation by the heating roller 21.

  When the curing failure detection process is started, the control unit 70 causes the head unit 34 to record a test image on the recording medium P (step S101). That is, the control unit 70 operates the medium delivery roller 12 to start conveyance of the recording medium P. Further, the control unit 70 causes the head unit 34 to start the test image recording operation at the timing when the recording medium P moves to the predetermined position facing the ink ejection surface of the head unit 34 according to the circumferential movement of the transport belt 311. . That is, the ink is discharged from the nozzle 343 to the recording medium P by supplying the control signal such as the discharge start pulse and the image data of the test image at appropriate timing from the head control unit 83 to the recording head 341. A test image containing a solid pattern of mid-tones is recorded.

  The control unit 70 causes the first imaging unit 35 to capture a test image on the recording medium P, and acquires first imaging data of the test image (step S102: reading step). That is, the control unit 70 causes the reading control unit 85 to send the first imaging unit 35 at a timing when the recording medium P moves to the first imaging range of the first imaging unit 35 according to the circumferential movement of the conveyance belt 311. A control signal is output and imaging of a test image by the first imaging unit 35 is started. Here, the reading control unit 85 outputs an imaging start pulse synchronized with the ejection start pulse to the first imaging unit 35, thereby performing one-dimensional imaging on each position in the transport direction on the recording medium P.

  The control unit 70 controls the ultraviolet irradiation control unit 84 to send a control signal to the ultraviolet irradiation unit 44 at the timing when the recording medium P to which the ink is applied moves to the ultraviolet irradiation range of the ultraviolet irradiation unit 44 according to the circumferential movement of the transport belt 411. , And starts the irradiation of ultraviolet light by the ultraviolet irradiation unit 44, that is, the irradiation operation. Thus, the ink on the recording medium P is cured and fixed on the recording medium P (step S103).

  The control unit 70 causes the second imaging unit 55 to capture a test image on the recording medium P, and acquires second imaging data of the test image (step S104: reading step). That is, the control unit 70 causes the reading control unit 85 to send the second imaging unit 55 at a timing when the recording medium P moves to the second imaging range of the second imaging unit 55 according to the circumferential movement of the conveyance belt 511. A control signal is output and imaging of a test image by the second imaging unit 55 is started.

  The control unit 70 determines whether the detection value of each pixel data in the second imaging data is within the above-described second reference range (step S105).

  When it is determined that at least a part of the detection value in the second imaging data is not within the second reference range (“NO” in step S105), the control unit 70 determines each pixel in the first imaging data. It is determined whether the detected value of the data is within the first reference range described above (step S106).

  When it is determined that the detection value of each pixel data in the first imaging data is within the first reference range ("YES" in step S106), the control unit 70 determines that the curing failure of the ink has occurred. An operation is performed to generate curing failure information indicating the predetermined operation in this case, in this case the presence or absence of curing failure of the ink, the range of occurrence of curing failure on the recording medium P, and the like, and store the information in the storage unit 74 (step S107). The control unit 70 may also perform an operation of displaying the content of the curing failure information on a predetermined display unit and an operation of causing the predetermined notification unit to perform a notification operation indicating that a curing failure has occurred. The process from step S105 to step S107 described above corresponds to a curing failure detection step.

  When it is determined that at least a part of the detection value in the first imaging data is not within the first reference range ("NO" in step S106), the control unit 70 performs the above-described recording failure handling operation. A recording failure handling process is executed (step S108).

  When the processing of step S107 or step S108 ends, or when it is determined that the detection value of each pixel data in the second imaging data is within the second reference range in the processing of step S105 (“in step S105 YES “), the control unit 70 ends the curing failure detection process.

(Modification)
Subsequently, a modification of the first embodiment will be described. The present modification is different from the above embodiment in the method of determining the presence or absence of curing failure based on the first imaging data and the second imaging data. Below, the difference with the said embodiment is demonstrated.

In the present modification, a normal image relating to a print job input from the external device 2 can be used for detection of curing failure of ink. When the curing failure of the ink is detected, the first imaging unit 35 captures the normal image before curing the ink to acquire the first imaging data, and the second imaging unit 55 captures the ink after curing the ink. A normal image is captured and second imaging data is acquired.
Then, by comparing the detection values of the pixel data of the first imaging data and the second imaging data, the plane distribution of the rate of change of gloss before and after curing of the ink in the recording range of the normal image on the recording medium P Is acquired. The rate of change of the gloss can be obtained from the ratio of the detection value of the second imaging data to the detection value of the first imaging data corresponding to the same position of the normal image.

In this modification, it is determined that the curing of the ink is properly performed at the position where the change rate of the gloss of the recording medium P is within the predetermined third reference range. On the other hand, at a position where the change rate of gloss of the recording medium P is not within the predetermined third reference range, it is determined that the curing failure of the ink occurs.
Here, the third reference range is the third predetermined test image (for example, a solid pattern of middle gradation) recorded in advance by the proper ink ejection by the head unit 34 and the proper irradiation operation by the ultraviolet irradiation unit 44. The change rate is set based on the comparison result of the imaging data by the first imaging unit 35 and the second imaging unit 55, and is the range of the change rate when there are no various defects including a curing failure and an ink discharge failure.

  Thus, according to the method using the rate of change in gloss before and after curing of the ink as an index, the color and density of the ink (that is, the magnitude of the detection value of pixel data in the imaging data) differ depending on the position in the image Also in the normal image, it can be determined whether the ink is properly cured at each position in the image. For this reason, in the present modification, the curing failure of the ink can be detected using an arbitrary print image. Also in the present modification, a curing failure of the ink may be detected using a test image such as a solid pattern of middle gradation.

As described above, in the inkjet recording apparatus 1 according to the first embodiment, the head unit 34 that discharges the ink cured by the ultraviolet light from the nozzle 343 and the ultraviolet light to the ink on the recording medium P discharged by the head unit 34 And a first imaging unit 35 and a second imaging unit 55 as a reading unit that reads the surface of the recording medium P, and a control unit 70. The control unit 70 images the surface of the recording medium P after the ink is ejected by the head unit 34 onto the recording medium P and before the irradiation operation on the ink on the recording medium P is performed. The first imaging unit 35 and the second imaging operation for imaging the surface of the recording medium P after the first imaging operation and the irradiation operation for the ink are performed, respectively. Of the ink on the recording medium P based on the first imaging data by the first imaging operation and the second imaging data by the second imaging operation. Detect (curing defect detection means).
According to such a configuration, whether the cause of the gloss unevenness or the color unevenness of the recorded image indicated by the second imaging data occurs before the start of curing of the ink or after the start of curing of the ink is the first It can be specified by referring to the imaging data. Therefore, when it is indicated that the above cause has occurred after the start of curing of the ink, it is possible to reliably detect the curing failure of the ink by determining that the curing failure of the ink is present. As a result, it is possible to easily take appropriate measures for the deterioration of the image quality of the recorded image. That is, when the cause of the deterioration of the image quality is the curing failure of the ink, the curing failure is surely specified, and appropriate measures are taken for the cause of the deterioration of the image quality such as repair or replacement of the ultraviolet irradiation part 44. it can. Thereby, it is possible to reliably suppress the image quality deterioration of the recorded image to be recorded later.

  In addition, the inkjet recording apparatus 1 includes a landing range of ink ejected by the head unit 34, an irradiation range of ultraviolet light by the ultraviolet light irradiation unit 44, and a path passing through an imaging range by the first imaging unit 35 and the second imaging unit 55. Transport units 31, 41, and 51 for transporting the recording medium P. According to such a configuration, the curing failure of the ink can be efficiently detected for the plurality of recording media P.

  The inkjet recording apparatus 1 also functions as a reading unit on the surface of the recording medium P conveyed by the conveyance unit 31 downstream of the landing range of the ink with respect to the conveyance direction of the recording medium P and upstream of the irradiation range of ultraviolet light. The first imaging unit 35 imaging in the first imaging range and the surface of the recording medium P transported by the transport unit 51 are imaged in the second imaging range on the downstream side of the ultraviolet radiation range in the transport direction A second imaging unit 55, and the control unit 70 performs a first imaging operation to read the surface of the recording medium P by imaging the surface of the recording medium P by the first imaging unit 35; The second imaging operation to be read by imaging by the imaging unit 55 is performed. According to such a configuration, the recording medium P is transported by the transport units 31, 41, 51, the landing range of the ink by the head unit 34, the first imaging range by the first imaging unit 35, and the ultraviolet radiation by the ultraviolet radiation unit 44. The irradiation range can be passed in the order of the second imaging range by the second imaging unit 55. Therefore, simple control is performed such that ink discharge from the head unit 34, imaging by the first imaging unit 35, ultraviolet irradiation by the ultraviolet irradiation unit 44, and imaging by the second imaging unit 55 in accordance with the passage of the recording medium P. The first imaging data and the second imaging data used to detect the curing failure of the ink can be acquired.

The transport units 31, 41 and 51 move the transport belts 311, 411 and 511 while delivering the recording medium P to be transported between the plurality of transport belts 311, 411 and 511 on which the recording media P are placed. The recording medium P is moved in the conveyance direction by the operation, and the recording medium P placed on the conveyance belt 311 is moved along the path passing the ink impact area by the head unit 34 by the circulation movement operation of the conveyance belt 311. The recording medium P moved by the conveyance belt 311 is placed on the conveyance belt 411, and is moved along the path passing the irradiation range of the ultraviolet light by the ultraviolet irradiation unit 44 by the circulation movement operation of the conveyance belt 411.
As described above, the head unit 34 is configured to perform the ink discharge by the head unit 34 and the ultraviolet irradiation by the ultraviolet irradiation unit 44 on the recording medium P in a state of being placed on the separate conveyance belts 311 and 411, respectively. It is possible to suppress the occurrence of the problem that the ink attached to the conveyance belt 311 is cured due to the erroneous ejection of the ink from the above, and the conveyance belt 311 is soiled.
Further, it is possible to suppress that the heat generated at the time of curing of the ink is transmitted to the recording medium P as the ink discharge target via the conveyance belt, and the temperature of the recording medium P at the time of ink landing becomes inappropriate. As a result, it is possible to suppress the occurrence of the problem that the image quality of the recorded image is degraded due to the temperature of the recording medium P at the time of ink landing.
In addition, since the sections where the recording medium P is placed on the transport belts 311, 411 and 511 in the transport units 31, 41 and 51 can be shortened, the expansion, extension, and movement speed of the transport belts 311, 411 and 511 can be reduced. It is possible to suppress the occurrence of the problem that the conveyance position accuracy of the recording medium P is lowered due to the non-uniformity or the like. Thus, for example, the image recording and reading unit 30 can discharge the ink to a desired position on the recording medium P.

  Further, the conveyance units 41 and 51 place the recording medium P moved by the conveyance belt 411 on the conveyance belt 511, and the second imaging unit 55 performs the second imaging by the circulation movement operation of the conveyance belt 511. Move along the route through the range. According to such a configuration, the ultraviolet irradiation by the ultraviolet irradiation unit 44 and the imaging by the second imaging unit 55 are performed on the recording medium P in a state of being placed on the separate conveyance belts 411 and 511, respectively. Can. As a result, it is possible to suppress the occurrence of the problem that the heat generated at the time of curing of the ink is transmitted to the second imaging unit 55 through the transport belt and the imaging characteristics of the second imaging unit 55 fluctuate.

  Also, the control unit 70 causes the head unit 34 to eject the ink from the nozzle 343 to the recording medium P, and causes the recording medium P to record a test image including a solid pattern (defect detection pattern) of a predetermined density (recording Control means) causing the first imaging unit 35 and the second imaging unit 55 to perform the first imaging operation and the second imaging operation on the recording medium P having the test image recorded thereon (reading control unit); Based on the first imaging data from the first imaging operation, the intensity of incident light from each position of the solid pattern is determined to be within the first reference range related to the detection of the ink ejection failure from the nozzle 343, and If the intensity of the incident light from at least a part of the solid pattern is not within the second reference range for detecting the curing failure of the ink based on the second imaging data by the second imaging operation If another has been, judges that there is a defective curing (curing failure detecting means). This makes it possible to easily identify whether the cause of uneven gloss or uneven color after ink curing has occurred either before the start of curing of the ink or after the start of curing of the ink. Therefore, based on the said specific result, the presence or absence of curing defect of ink can be discriminate | determined reliably.

  In the defect detection method of the present embodiment, the surface of the recording medium P after the ink is ejected by the head unit 34 onto the recording medium P and before the irradiation operation on the ink on the recording medium P is performed The first imaging unit 35 and the second imaging unit 55 perform the first imaging operation for imaging and the second imaging operation for imaging the surface of the recording medium P after the irradiation operation for ink is performed. An imaging step includes a curing failure detection step of detecting a curing failure of the ink on the recording medium P based on the first imaging data by the first imaging operation and the second imaging data by the second imaging operation. According to such a method, whether the cause of uneven gloss or uneven color of the recorded image indicated by the second imaging data occurs before the start of curing of the ink or after the start of curing of the ink is It can be specified by referring to the imaging data. Therefore, when it is indicated that the above cause has occurred after the start of curing of the ink, it is possible to reliably detect the curing failure of the ink by determining that the curing failure of the ink is present.

Second Embodiment
Subsequently, a second embodiment of the present invention will be described. The present embodiment is different from the first embodiment in that the curing failure of the ink is detected using the detection result of the ink discharge failure. The differences from the first embodiment will be described below.

  In the present embodiment, when detecting the curing failure of the ink, the recording medium P includes a solid pattern of middle gradation and a test image including a discharge failure detection pattern for detecting the ink discharge failure as a failure detection pattern. The test image before and after curing of the ink is captured by the first imaging unit 35 and the second imaging unit 55, respectively.

FIG. 6 is a view showing an example of the ejection failure detection pattern PT included in the test image.
When detecting an ink landing position (ejection direction) abnormality or an ink ejection amount abnormality in the width direction from each nozzle 343, for example, as shown in FIG. 6A, it extends in the transport direction A discharge failure detection pattern PT in which a plurality of lines L are formed is recorded. The line L in FIG. 6A is recorded by discharging ink at regular discharge intervals from the nozzles 343 every three nozzles on the recording medium P conveyed in the conveyance direction. Each line L is formed of ink ejected from a single nozzle 343. Therefore, the ink landing position from the nozzle 343 is detected by detecting the position in the width direction of the line L from the imaging result of the test image. It is possible to detect the presence or absence of an abnormality in (ejection direction). Also, the nozzle 343 corresponding to the missing line L can be identified as a defective nozzle (missing nozzle) that does not eject ink. Further, based on the density of the line L (the detected value in the imaging data), it is possible to detect the presence or absence of abnormality of the ink ejection amount from the nozzle 343. Further, when the landing positions of the ink from the nozzles 343 belonging to the recording head 341 and the head module 342 are shifted to the whole, it is possible to detect an error in the mounting positions of the recording head 341 and the head module 342.
Further, as shown in FIG. 6B, by using the ejection failure detection pattern PT in which a plurality of dots D recorded by each nozzle 343 are formed, the ink landing position in the transport direction from the nozzle 343 is further reduced. Abnormality (abnormality of ejection direction and ejection speed) can be detected.
These ejection failure detection patterns PT are preferably formed separately for each of the CMYK colors.

  The detection of the ink ejection defect based on the imaging data of such an ejection defect detection pattern can be more accurately performed by using the imaging data by the first imaging unit 35. This is because the placement angle of the recording medium P on the transport belt 311 does not change between the time of ink ejection by the head unit 34 and the time of imaging by the first imaging unit 35, so the line L and the nozzles 343 and It is because the correspondence of can be performed correctly. In addition, by using the first imaging unit 35, the head units are respectively output to the recording medium P transported on the same transport belt 311 in accordance with the discharge start pulse and the imaging start pulse output at the timing synchronized with each other. Since one-dimensional imaging can be performed by the ink 34 and the first imaging unit 35, imaging can be performed accurately at an ink ejection position interval in the transport direction by the head unit 34. As a result, generation of a pseudo signal (moire) generated in the imaging data due to the deviation of the spatial frequency related to the ink ejection position interval and the imaging position interval in the transport direction can be suppressed. The position can be specified with high accuracy and the ink discharge failure can be detected accurately.

As described above, since the first imaging unit 35 in the present embodiment is used to detect the position of the line L or the dot D in the ejection failure detection pattern PT, the nozzle 343 used for recording the line L or the dot D is specified. Possible high resolution ones are used. On the other hand, it is sufficient for the second imaging unit 35 to be able to detect the luminance value in the area across the arrangement range of the plurality of nozzles 343, and therefore, one having a resolution lower than that of the first imaging unit 35 can be used. Therefore, as the line sensor of the first imaging unit 35, one in which the arrangement pitch of the imaging elements in the width direction is smaller than the arrangement pitch in the second imaging unit 55 is used.
In addition, since it is sufficient that the first imaging unit 35 can detect the position of the line L or the dot D from the imaging data, only an imaging element that detects the spectral intensity of incident light with the same spectral sensitivity characteristic is arranged as a line sensor. Alternatively, one that performs imaging (imaging in a single color) for one color component may be used. In addition, when it is not necessary to detect a defect related to the amount of ejected ink with high accuracy (for example, when only a missing nozzle is detected), an imaging element with low luminance detection resolution (for example, 1 bit 2 gradations) You may use the line sensor by which the imaging element which outputs a detected value was arranged.

In the method for detecting the curing failure of the ink according to the present embodiment, when the first imaging data of the test image by the first imaging unit 35 and the second imaging data of the test image by the second imaging unit 55 are acquired, First, as in the first embodiment, it is determined based on the second imaging data whether uneven gloss or uneven color occurs in the test image after ink curing.
When uneven gloss or color unevenness occurs, that is, when at least a part of the detected value in the second imaging data is not within the second reference range, the ejection failure detection pattern in the first imaging data is supported. The portion to be analyzed is analyzed by the above-described method to detect an ink discharge failure. Here, the reason why the first imaging data is used is that the ink ejection failure can be more accurately detected as described above. When no ink discharge failure is detected from the first imaging data, uneven gloss or color after curing of the ink determined based on the second imaging data occurs in the process of curing the ink. And is determined to be due to curing failure of the ink.
On the other hand, when an ink ejection failure is detected from the first imaging data, gloss unevenness or color unevenness after ink curing determined based on the second imaging data may be caused by the ink ejection failure. It will be sex. For this reason, in this case, a predetermined ink discharge failure handling operation for the ink discharge failure is performed.

  For example, the following operation is performed as the ink discharge failure handling operation. That is, when a defective nozzle that does not eject ink or a defective nozzle with an ink landing position abnormality in the width direction is detected, for example, the ink from the defective nozzle is not ejected and is ejected by the defective nozzle. The ink discharge operation from the nozzle 343 by the head unit 34 is adjusted such that the ink which should be compensated for is complemented by increasing the amount of ink discharged from the nozzle 343 around the defective nozzle. In addition, when a defective nozzle with an ink landing position abnormality in the transport direction is detected, the ink landing position is corrected by performing setting for adjusting the ink discharge timing. Further, when it is indicated from the detection result of the ink ejection failure that an error occurs in the mounting position of the recording head 341 and the head module 342, the position adjustment of the recording head 341 and the head module 342 is performed.

Subsequently, a control procedure by the control unit 70 of the curing failure detection process in the present embodiment will be described.
FIG. 7 is a flowchart showing the control procedure of the curing failure detection process according to the present embodiment.
This flowchart is obtained by changing step S101 of the flowchart (FIG. 5) of the defective curing detection process in the first embodiment to step S101a, deleting step S106 from step S106, and adding step S109 to step S112. . Hereinafter, differences from the flowchart of FIG. 5 will be described.

  When the curing failure detection process is started, the control unit 70 causes the head unit 34 to record a test image on the recording medium P (step S101a). Here, the control unit 70 records a test image including the ejection failure detection pattern PT and a solid pattern of middle gradation. The process in step S101a is the same as step S101 in FIG. 5 except for the content of the test image.

  The control unit 70 determines whether the detection value of each pixel data of the portion corresponding to the solid pattern in the second imaging data is within the above-described second reference range (step S105), and at least the detection value is detected. If it is determined that a part is not within the second reference range ("NO" in step S105), the ink ejection failure is detected by the above-described method based on the first imaging data (step S109).

  The control unit 70 determines whether there is an ink discharge failure (step S110). If it is determined that there is no ink discharge failure ("NO" in step S110), it is determined that there is an ink curing failure. Then, a predetermined operation when the curing failure of the ink occurs, in this case, an operation of generating the curing failure information related to the curing failure of the ink and storing it in the storage unit 74 (step S111). The control unit 70 may also perform an operation of displaying the content of the curing failure information on a predetermined display unit and an operation of causing the predetermined notification unit to perform a notification operation indicating that a curing failure has occurred. The processes from step S105 and step S109 to step S111 correspond to the curing failure detection step. When it is determined that there is an ink discharge failure (“YES” in step S110), the control unit 70 executes the ink discharge failure handling process for performing the above-described ink discharge failure handling operation (step S112). ).

  When the process of step S111 or step S112 ends, or when it is determined that the detection value of each pixel data in the second imaging data is within the second reference range in the process of step S105 (“in step S105 YES “), the control unit 70 ends the curing failure detection process.

  As described above, in the inkjet recording apparatus 1 according to the second embodiment, the conveyance unit 31 causes the recording medium P placed on the conveyance belt 311 to move by the movement of the conveyance belt 311 so that the head unit 34 The landing range and the first imaging range by the first imaging unit 35 are moved along a path that sequentially passes through. As described above, by performing the ink discharge by the head unit 34 and the imaging by the first imaging unit 35 on the recording medium P conveyed on the same conveyance belt 311, the ink discharge by the head unit 34 and The placement angle of the recording medium P on the conveyance belt 311 can be prevented from changing between when the first imaging unit 35 captures an image. As a result, the detection target image (for example, the line L) in the discharge failure detection pattern can be accurately associated with the nozzle 343 used for printing the detection target image, so that the ink discharge failure can be performed more accurately. It can be detected.

In addition, the control unit 70 causes the head unit 34 to eject ink onto the recording medium P, and records a test image including an ejection failure detection pattern for detecting an ink ejection failure from the nozzles 343 of the head unit 34. The recording is performed on the medium P (recording control means), and the first imaging unit 35 and the second imaging unit 55 perform the first imaging operation and the second imaging operation on the recording medium P on which the test image is recorded. (Reading control means) detects an ink discharge failure based on the first imaging data by the first imaging operation, and cures based on the detection result of the ink discharge failure and the second imaging data by the second imaging operation A defect is detected (curing defect detection means).
According to this, it is possible to determine whether there is a possibility that the gloss unevenness or color unevenness of the recorded image indicated by the second imaging data may be due to the ink ejection failure from the head unit 34. Therefore, when it is determined that the above cause is not due to the ink discharge failure, it is possible to reliably detect the curing failure of the ink by determining that there is the curing failure of the ink.
Further, detection of uneven gloss or uneven color may be performed based on the second imaging data by the second imaging unit 55, and the first imaging data by the first imaging unit 35 is used to detect an ink ejection failure. As it is used, the detection accuracy of the ink discharge failure and the curing failure can be improved by optimizing the configuration of the first imaging unit 35 and the second imaging unit 55 for each purpose, and the inkjet An increase in the manufacturing cost of the recording apparatus 1 can be suppressed.

  Further, by making the imaging characteristics of the first imaging unit 35 and the characteristics of imaging by the second imaging unit 55 different from each other, the configurations of the first imaging unit 35 and the second imaging unit 55 can be obtained. Can be optimized for the purpose of

  For example, by setting the imaging resolution by the first imaging unit 35 higher than the imaging resolution by the second imaging unit 35, the detection target image (for example, line L) in the ejection failure detection pattern and the recording of the detection target image Since the correspondence with the used nozzle 343 can be made accurately, it is possible to detect the ink discharge failure more accurately. Further, by relatively reducing the imaging resolution of the second imaging unit 55, the configuration of the second imaging unit can be simplified, and an increase in the manufacturing cost of the inkjet recording apparatus 1 can be suppressed.

  In addition, the first imaging unit 35 detects incident light from the surface of the recording medium P with one spectral sensitivity characteristic to image the surface of the recording medium P, and the second imaging unit 55 detects a plurality of different images. Incident light from the surface of the recording medium P is detected with spectral sensitivity characteristics, and the surface of the recording medium P is imaged. As a result, the first imaging unit 35 can be simplified to such an extent that acquisition of imaging data used to detect an ink ejection failure is possible, and an increase in the manufacturing cost of the inkjet recording apparatus 1 can be suppressed. In addition, since the second imaging unit 55 can perform imaging in a plurality of colors and acquire second imaging data capable of detecting uneven gloss and uneven color, it is possible to more accurately detect the curing failure of the ink. .

  In addition, the control unit 70 causes the head unit 34 to perform the discharge operation of discharging the ink from the nozzles 343 plural times at predetermined discharge time intervals with respect to the recording medium P conveyed by the conveyance unit 31 at a predetermined speed. Thus, the test image is recorded (recording control means), and the surface of the recording medium P being conveyed by the conveyance unit 31 at the above-mentioned predetermined speed is plural times by the first imaging unit 35 at the same time intervals as the ejection time intervals. The first imaging unit 35 causes the first imaging unit 35 to image a range where the ink ejected onto the recording medium P has landed in one ejection operation in each of the plurality of imaging operations (reading control means). As a result, in the transport direction, the first imaging unit 35 can accurately perform imaging with respect to each landing range of the ink by the head unit 34. As a result, it is possible to suppress generation of a pseudo signal (moire) generated in the imaging data due to the deviation of the spatial frequency relating to the ink ejection position interval and the imaging position interval in the transport direction. The position can be specified with high accuracy and the ink discharge failure can be detected accurately.

Third Embodiment
Subsequently, a third embodiment of the present invention will be described. The present embodiment differs from the first and second embodiments in the method of transporting the recording medium P, the number of imaging units, and the method of imaging a test image. Hereinafter, differences from the first and second embodiments will be described.

FIG. 8 is a view showing a schematic configuration of the ink jet recording apparatus 1 according to the third embodiment.
The inkjet recording apparatus 1 of the present embodiment includes a recording medium supply unit 10, an image recording and reading unit 30, and a recording medium discharge unit 60.

  The recording medium supply unit 10 has a mounting tray 11 for storing the recording medium P, and a medium supply belt 13 for conveying the recording medium P from the mounting tray 11 to the image recording and reading unit 30 and supplying the recording medium P. The medium supply belt 13 includes a ring-shaped belt supported by two rollers on the inside, and the recording medium P is placed on the belt by rotating the roller from the placement tray 11 from the placement tray 11 The sheet is conveyed to the image recording and reading unit 30.

  The image recording and reading unit 30 includes a transport unit 31 (transport unit), a head unit 34 (ink discharge unit), a first imaging unit 35 (reading unit), a delivery unit 36, a heating unit 37, and a delivery unit. And a UV irradiation unit 44 and the like.

  The conveyance unit 31 holds the recording medium P placed on the placement surface (outer peripheral surface) of the cylindrical conveyance drum 314 (conveyance member), and the conveyance drum 314 has a width direction perpendicular to the drawing in FIG. The recording medium P on the transport drum 314 is transported in the transport direction by rotating and rotating around a rotation axis (cylindrical axis) extending in the direction. The transport drum 314 includes claws and an intake portion (not shown) for holding the recording medium P on the mounting surface. The recording medium P is held on the placement surface by the end thereof being held down by the claws and being attracted to the placement surface by the intake unit. The transport unit 31 has a transport motor 861 for rotating the transport drum 314, and the transport drum 314 rotates by an angle proportional to the amount of rotation of the transport motor 861.

  The delivery unit 36 delivers the recording medium P conveyed by the medium supply belt 13 of the recording medium supply unit 10 to the conveyance unit 31. The delivery unit 36 is provided at a position between the medium supply belt 13 of the recording medium supply unit 10 and the conveyance unit 31 and holds one end of the recording medium P conveyed from the medium supply belt 13 by the swing arm unit 361. It picks up and delivers to the conveyance part 31 via the delivery drum 362.

  The heating unit 37 is provided between the arrangement position of the delivery drum 362 and the arrangement position of the head unit 34, and the recording medium P conveyed by the conveyance unit 31 has a temperature within a predetermined temperature range. Heat P. The heating unit 37 includes, for example, a heater 811, and based on a control signal supplied from the medium heating control unit 81, the heater 811 is energized to cause the heater 811 to generate heat.

  The delivery unit 38 includes a belt loop 382 having an annular belt supported by two rollers on the inside, and a cylindrical delivery drum 381 for delivering the recording medium P from the transport unit 31 to the belt loop 382. The recording medium P delivered from the transport unit 31 onto the belt loop 382 by the delivery drum 381 is transported by the belt loop 382 and delivered to the recording medium discharge unit 60.

  In the image recording / reading unit 30 of the present embodiment, the head unit 34 has a predetermined distance from the upstream side in the conveyance direction of the recording medium P such that the ink ejection surface and the placement surface of the conveyance drum 314 are separated by a predetermined distance. Four are arranged to line up at intervals. The configuration of the head unit 34 is the same as that of the first embodiment, so the description will be omitted.

  Further, in the image recording and reading unit 30 of the present embodiment, the ultraviolet irradiation unit 44 faces the placement surface in the transport direction from the arrangement position of the head unit 34 to the arrangement position of the delivery drum 381 of the delivery unit 38. Be placed. Therefore, in the present embodiment, curing and fixing of the ink are performed in the image recording and reading unit 30.

  In the first imaging unit 35, the surface of the recording medium P on the mounting surface of the conveyance drum 314 at a position between the fixing position of the ink by the ultraviolet irradiation unit 44 and the arrangement position of the delivery drum 38 in the conveyance direction. Are arranged to be capable of imaging. The configuration of the first imaging unit 35 is the same as that of the first embodiment, and thus the detailed description is omitted.

In the inkjet recording apparatus 1 of this embodiment having such a configuration, the recording medium P is conveyed by the conveyance drum 314, and the recording medium P is ejected by discharging the ink from the head unit 34 at an appropriate timing according to the conveyance position. Images can be recorded on top. In addition, the recording medium P conveyed by causing the ultraviolet irradiation unit 44 to start ultraviolet irradiation at the timing when the recording medium P from which the ink is discharged passes the ultraviolet irradiation range of the ultraviolet irradiation unit 44 by the rotation of the conveyance drum 314. The above ink can be cured. Further, by causing the first imaging unit 35 to perform imaging at the timing when the recording medium P passes through the first imaging range of the first imaging unit 35 by the rotation of the conveyance drum 314, the surface of the recording medium P is obtained. Imaging data can be acquired.
Here, the transport drum 314 can rotate once while the recording medium P is placed. For this reason, the transport drum 314 is rotated two or more turns in the state where the same recording medium P is mounted, and the imaging by the first imaging unit 35 is performed in each rotation, so that the surface of the recording medium P is different. It can be imaged multiple times.

Next, the detection operation of the curing failure of the ink in the ink jet recording apparatus 1 of the present embodiment will be described.
In order to detect the curing failure of the ink in the inkjet recording apparatus 1 of the present embodiment, first, a test image including a solid pattern of predetermined middle gradation is recorded by discharging the ink from the head unit 34. Then, the recording medium P from which the ink has been discharged is transported in a state where the ultraviolet light irradiation unit 44 does not irradiate ultraviolet light, and passes the ultraviolet light irradiation range of the ultraviolet light irradiation unit 44. A test image is captured to acquire first imaging data. After that, the recording medium P is circulated by the rotation of the conveyance drum 314, and the ultraviolet irradiation by the ultraviolet irradiation unit 44 is performed at the timing when the recording medium P moves to the irradiation range of the ultraviolet irradiation unit 44 again. Cure the above ink. In addition, after the ink is cured, the test image is captured at timing when the recording medium P passes through the first imaging range of the first imaging unit again, and the second imaging data of the test image after ink curing is acquired Do.
The following method of detecting the curing failure of the ink based on the first and second imaging data is the same as that of the first embodiment.

  In the present embodiment, the curing failure of the ink can also be detected by the method of the second embodiment described above by using a test image including the ejection failure detection pattern and the solid pattern instead of the above. In this case, the first imaging unit 35 has an imaging resolution capable of detecting an ink ejection defect based on the imaging data of the ejection failure detection pattern, and the ink curing failure based on the imaging data of the solid pattern What can detect the intensity | strength of incident light with the gradation number which can detect H is used.

  As described above, in the present embodiment, both the first imaging data before ink curing and the second imaging data after ink curing are acquired by the single imaging unit (first imaging unit 35), and the ink It is used to detect curing failure. Thus, the number of imaging units can be reduced, so that the inkjet recording apparatus 1 can be miniaturized, and the manufacturing cost can be suppressed.

The present invention is not limited to the above embodiment and each modification, and various modifications are possible.
For example, the second imaging unit 55 in the first and second embodiments may be provided in the fixing unit 40 when the influence of heat at the time of ink curing is negligible or slight.
In addition, the head unit 34, the first imaging unit 35, the ultraviolet irradiation unit 44, and the second imaging unit 35 may be provided at a position facing the mounting surface of the same conveyance belt.

  Further, in the conveyance units 31, 41 and 51 in the first and second embodiments, the recording medium P is conveyed by circulating the conveyance belts 311, 411 and 511 as conveyance members. For example, a transport drum as shown in the third embodiment may be used as a transport member, and the recording medium P may be delivered and transported among a plurality of transport drums.

  In the third embodiment, the second imaging unit 55 may be provided on the side opposite to the first imaging unit 35 side with respect to the ultraviolet irradiation unit 44 with respect to the rotation direction of the mounting surface of the conveyance drum 314 .

  In each of the above embodiments, the single-pass type inkjet recording apparatus 1 has been described as an example, but the present invention may be applied to an inkjet recording apparatus that performs recording of an image while scanning a recording head.

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

Reference Signs List 1 inkjet recording apparatus 2 external apparatus 10 recording medium supply unit 11 placement tray 12 medium delivery roller 13 medium supply belt 20 recording medium heating unit 21 heating roller 30 image recording and reading unit 31, 41, 51 conveyance unit 311, 411, 511 conveyance Belts 312, 412, 512 Drive rollers 313, 413, 513 Followed rollers 314 Transport drums 32, 42, 52 Support suction units 33, 43, 53 Pressure rollers 34 Head unit 341 Recording head 342 Head module 343 Nozzle 35 First imaging unit 36 delivery unit 37 heating unit 38 delivery unit 40 fixing unit 44 ultraviolet irradiation unit 50 image reading unit 55 second imaging unit 60 recording medium discharge unit 61 discharge tray 62 guide roller 70 control unit 71 CPU
72 RAM
73 ROM
74 storage unit 81 medium heating control unit 82 suction control unit 83 head control unit 84 ultraviolet irradiation control unit 85 reading control unit 86 transport control unit 87 input / output interface 88 bus P recording medium PT discharge failure detection pattern

Claims (13)

An ink discharge unit that discharges an ink which is cured by a predetermined energy beam from a nozzle;
An energy ray irradiation unit performing an irradiation operation of curing the ink by irradiating the ink on the recording medium discharged by the ink discharge unit with the predetermined energy ray;
Reading means for reading the surface of the recording medium;
A first reading operation for reading the surface of the recording medium after the ink is ejected by the ink discharge unit onto the recording medium and before the irradiation operation for the ink on the recording medium is performed, and the ink for the ink Reading control means for causing the reading means to perform a second reading operation for reading the surface of the recording medium after the irradiation operation has been performed;
Curing failure detecting means for detecting curing failure of the ink on the recording medium based on the reading result by the first reading operation and the reading result by the second reading operation;
An inkjet recording apparatus comprising:   It further comprises conveying means for conveying the recording medium along a path passing through the landing range of the ink ejected by the ink ejection unit, the irradiation range of the predetermined energy beam by the energy ray irradiation unit, and the reading range by the reading unit. The ink jet recording apparatus according to claim 1, characterized in that The reading means is
The surface of the recording medium conveyed by the conveyance means is a first side of the ink impacting area downstream of the ink impacting area in the conveyance direction of the recording medium by the conveyance means and upstream of the predetermined energy beam irradiation area. A first imaging unit for imaging in the imaging range of
A second imaging unit configured to image the surface of the recording medium conveyed by the conveyance means in a predetermined second imaging range on the downstream side of the irradiation range of the predetermined energy beam in the conveyance direction;
Have
The reading control means reads the first reading operation to read by imaging the surface of the recording medium by the first imaging unit, and reads the image by imaging the surface of the recording medium by the second imaging unit. The inkjet recording apparatus according to claim 2, wherein the second reading operation is performed by the reading unit. The transport means is
Moving the recording medium in the conveyance direction by moving the conveyance members while transferring the recording medium to be conveyed between the plurality of conveyance members on which the recording medium is placed;
The recording medium placed on the first transport member of the plurality of transport members is moved along a path passing through the landing area of the ink by the movement operation of the first transport member.
The recording medium moved by the first conveyance member is placed on the second conveyance member of the plurality of conveyance members, and irradiation of the predetermined energy beam is performed by the movement operation of the second conveyance member. The ink jet recording apparatus according to claim 3, wherein the ink jet recording apparatus is moved along a path passing through a range.   The transport means moves the recording medium placed on the first transport member along a path sequentially passing through the landing range of the ink and the first imaging range by the movement operation of the first transport member. The ink jet recording apparatus according to claim 4,   The transport means places the recording medium moved by the second transport member on a third transport member of the plurality of transport members, and the moving operation of the third transport member The ink jet recording apparatus according to claim 4 or 5, wherein the ink jet recording apparatus is moved along a path passing through two imaging ranges. Recording control means for causing the ink discharge unit to discharge the ink from the nozzle to the recording medium and recording a test image including a defect detection pattern of a predetermined density on the recording medium;
The reading control means causes the reading means to perform the first reading operation and the second reading operation on the recording medium on which the test image is recorded.
The curing failure detection means is a first reference range in which the intensity of incident light from each position of the failure detection pattern relates to the detection of the ink discharge failure from the nozzle based on the reading result by the first reading operation. A second reference range in which the intensity of incident light from at least a part of the defect detection pattern is based on the detection result of the ink based on the reading result by the second reading operation. The ink jet recording apparatus according to any one of claims 1 to 6, wherein it is determined that the curing failure is present when it is determined that the inside is not the inside. A test image including a defect detection pattern for causing the ink ejection unit to eject ink onto the recording medium from the nozzle and detecting an ink ejection failure from the nozzle of the ink ejection unit is recorded on the recording medium. Recording control means to
The reading control means causes the reading means to perform the first reading operation and the second reading operation on the recording medium on which the test image is recorded.
The curing failure detection unit detects the ink discharge failure based on the reading result by the first reading operation, and the curing failure is based on the detection result of the ink discharging failure and the reading result by the second reading operation. The ink jet recording apparatus according to any one of claims 1 to 6, which detects A test image including a defect detection pattern for causing the ink ejection unit to eject ink onto the recording medium from the nozzle and detecting an ink ejection failure from the nozzle of the ink ejection unit is recorded on the recording medium. Recording control means to
The imaging characteristic of the first imaging unit and the imaging characteristic of the second imaging unit are different from each other
The reading control means causes the reading means to perform the first reading operation and the second reading operation on the recording medium on which the test image is recorded.
The curing failure detection unit detects the ink discharge failure based on the reading result by the first reading operation, and the curing failure is based on the detection result of the ink discharging failure and the reading result by the second reading operation. The ink jet recording apparatus according to any one of claims 3 to 6, which detects   10. The inkjet recording apparatus according to claim 9, wherein an imaging resolution by the first imaging unit is higher than an imaging resolution by the second imaging unit.   The first imaging unit detects incident light from the surface of the recording medium with one spectral sensitivity characteristic to image the surface of the recording medium, and the second imaging unit has a plurality of different spectral sensitivity characteristics. The ink jet recording apparatus according to claim 9 or 10, wherein incident light from the surface of the recording medium is detected to pick up an image of the surface of the recording medium. The recording control unit causes the ink discharge unit to perform the discharge operation of discharging the ink from the nozzles a plurality of times at predetermined discharge time intervals with respect to the recording medium being conveyed at a predetermined speed by the conveyance unit. Record the test image with
The reading control means causes the first imaging unit to image the surface of the recording medium being conveyed at the predetermined speed by the conveying means a plurality of times at the same time interval as the ejection time interval, and the plurality of times The imaging unit according to any one of claims 9 to 11, wherein, in each of the imaging operations, the first imaging unit captures an area where the ink ejected onto the recording medium has landed in one ejection operation. The inkjet recording device as described in a term. An ink ejection unit that ejects an ink that is cured by a predetermined energy beam from a nozzle, and an irradiation that cures the ink by irradiating the ink on the recording medium ejected by the ink ejection unit with the predetermined energy beam An ink jet recording apparatus comprising: an energy beam irradiating unit for performing operation; and a reading unit for reading a surface of the recording medium, wherein the method is a defect detection method for detecting a curing failure of ink on the recording medium,
A first reading operation for reading the surface of the recording medium after the ink is ejected by the ink discharge unit onto the recording medium and before the irradiation operation for the ink on the recording medium is performed, and the ink for the ink A reading step of causing the reading means to perform a second reading operation for reading the surface of the recording medium after the irradiation operation has been performed;
A curing failure detection step of detecting curing failure of the ink on the recording medium based on the reading result by the first reading operation and the reading result by the second reading operation;
A defect detection method comprising:

Images