JP2017228955A - Ink jet recording device and image reading method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording device and an image reading method therefor, capable of securely reading an image in an appropriate range of a recording medium.SOLUTION: The ink jet recording device includes: transfer means which loads a recording medium on a predetermined position of a transfer member which moves circularly, to perform transfer operation to transfer the recording medium; recording means which ejects ink to the recording medium which moves by the transfer operation to record an image; reading means which performs reading operation to read the image recorded on the recording medium by the recording means; position association information acquisition means which acquires position association information associated with the position based on the circular movement of the transfer member; and reading control means which controls the start timing of the reading operation by the reading means on the basis of the position association information acquired by the position association information acquisition means.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an ink jet recording apparatus and an image reading method of the ink jet recording apparatus.

  2. Related Art There is an ink jet recording apparatus that records an image on a recording medium by ejecting ink from a recording element of a recording head in accordance with image data with respect to the recording medium that is mounted on the conveying surface of the conveying unit and conveyed. . Some inkjet recording apparatuses include a reading unit that reads an image recorded on a recording medium placed on a conveyance surface. In such an ink jet recording apparatus, based on the reading result by the reading means of the test image recorded by the ink discharge from the recording element, the defective recording element is specified or the ink discharging operation from the recording element is adjusted. Can be.

  Conventionally, when an image on a recording medium is read by a reading unit, an image reading operation by the reading unit is started based on the timing at which the leading end is detected by a sensor that detects contact with the leading end of the conveyed recording medium. There is a technique for adjusting the timing (for example, Patent Document 1). Here, the method for detecting the leading edge of the recording medium is not limited to the method for detecting physical contact with the recording medium, and the method for detecting based on the difference in reflectance between the conveyance surface and the recording medium surface, depends on the recording medium. A method for detecting blocking of predetermined reference light, a method for detecting a change in the conveyance surface and a distance to the recording medium on the conveyance surface, and the like can be used.

JP 2010-252250 A

  However, in the above conventional technology, depending on the combination of the detection method of the tip of the recording medium and the type of the recording medium, an error may occur in the detection position of the tip or the tip may not be detected correctly. There is a problem that an image in an appropriate range on the medium may not be read.

  An object of the present invention is to provide an ink jet recording apparatus and an image reading method of the ink jet recording apparatus that can read an image in an appropriate range on a recording medium more reliably.

In order to achieve the above object, the invention of the ink jet recording apparatus according to claim 1 comprises:
A conveying means for performing a conveying operation of placing the recording medium at a predetermined placement position on the conveying member that moves around and conveying the recording medium;
Recording means for recording an image by ejecting ink to a recording medium that moves by the conveying operation;
Reading means for performing a reading operation of reading an image recorded on the recording medium by the recording means;
Position correspondence information acquisition means for acquiring position correspondence information corresponding to a position corresponding to the circular movement of the transport member;
Reading control means for controlling the start timing of the reading operation by the reading means based on the position correspondence information acquired by the position correspondence information acquisition means;
It is characterized by having.

According to a second aspect of the present invention, in the ink jet recording apparatus of the first aspect,
The start timing is determined as a timing at which the position of the conveying member coincides with a reading operation start position set in advance according to the placement position.

The invention according to claim 3 is the ink jet recording apparatus according to claim 2,
The reading operation start position is the conveying member when the leading end of the recording medium placed at the setting position and the position where reading by the reading unit is performed have a predetermined positional relationship in the direction of the circular movement It is characterized by the position.

The invention according to claim 4 is the ink jet recording apparatus according to claim 2 or 3,
Comprising storage means for storing reading operation start position information indicating the reading operation start position;
The start timing is defined as a timing at which the position of the transport member coincides with the reading operation start position indicated by the reading operation start position information.

The invention according to claim 5 is the ink jet recording apparatus according to claim 4,
Detecting means for detecting the leading edge of the recording medium placed and conveyed at the placement position;
The reading operation start position information is set based on the position correspondence information acquired by the position correspondence information acquisition unit when the leading end of the recording medium is detected by the detection unit, and the reading operation start position information is stored in the memory. Reading operation start position setting means stored in the means;
It is characterized by having.

The invention according to claim 6 is the ink jet recording apparatus according to any one of claims 2 to 5,
A plurality of the above-described placement positions are set on the conveying member.

The invention according to claim 7 is the ink jet recording apparatus according to any one of claims 2 to 5,
Reversing means for reversing the front and back of the recording medium placed on the conveying member and placing the recording medium at the placement position;
After the image is recorded on one surface of the recording medium by the recording means, the front and back of the recording medium are reversed by the reversing means, and the image is recorded by the recording means on the other surface of the recording medium. Recording control means;
With
The reading operation start position is set in advance for each of the case where the surface of the recording medium on which the image read by the reading operation is recorded is the one surface and the other surface.

The invention according to claim 8 is the ink jet recording apparatus according to claim 6,
Reversing means for reversing the front and back of the recording medium placed on the conveying member and placing it on any of the plurality of placement positions;
After the image is recorded on one surface of the recording medium by the recording means, the front and back of the recording medium are reversed by the reversing means, and the image is recorded by the recording means on the other surface of the recording medium. Recording control means;
With
The reading operation start position is preset in each case where the surface of the recording medium on which the image read by the reading operation is recorded at each of the plurality of mounting positions is the one surface and the other surface. It is characterized by being set.

The invention according to claim 9 is the ink jet recording apparatus according to any one of claims 1 to 8,
The position correspondence information acquisition unit acquires the position correspondence information indicating a movement amount of the transport member from a predetermined reference position in the transport operation.

The invention according to claim 10 is the ink jet recording apparatus according to claim 9,
The position correspondence information acquisition unit includes a movement detection unit that outputs a predetermined detection signal for each movement of the conveyance member by a predetermined amount, and acquires the position correspondence information from the output detection signal. Yes.

The invention according to claim 11 is the ink jet recording apparatus according to any one of claims 1 to 10,
The position correspondence information acquisition means has a rotary encoder.

The invention according to claim 12 is the inkjet recording apparatus according to any one of claims 1 to 11,
The transport means has a position defining portion that prescribes the mounting position on the transport member,
The recording medium is characterized in that at least one of the front end and the rear end of the recording medium is placed and transported by the position defining portion at the pre-determined mounting position.

The invention according to claim 13 is the ink jet recording apparatus according to claim 12,
The transporting unit includes a sandwiching unit that sandwiches the end of the recording medium, at least one of the leading end and the trailing end being stopped by the position defining unit, with the transporting member.

The invention according to claim 14 is the ink jet recording apparatus according to any one of claims 1 to 13,
The conveying means has a cylindrical drum, the recording medium is placed on an outer peripheral curved surface of the drum, and the conveying operation is performed by rotating the drum around a cylindrical axis. .

In order to achieve the above object, an invention of an image reading method of an ink jet recording apparatus according to claim 15 comprises:
A transport unit that performs a transport operation for transporting the recording medium by placing the recording medium on a predetermined mounting position on a transport member that circulates; and ejects ink to the recording medium that is moved by the transport operation. Recording means for recording an image; reading means for performing a reading operation for reading an image recorded on the recording medium by the recording means; and position correspondence information corresponding to a position corresponding to the circular movement of the conveying member An image reading method of an ink jet recording apparatus comprising:
A reading control step of controlling the start timing of the reading operation by the reading unit based on the position correspondence information acquired by the position correspondence information acquisition unit is included.

The invention according to claim 16 is the image reading method according to claim 15,
The start timing is determined as a timing at which the position of the transport member coincides with a reading operation start position set in advance according to the above-described placement position,
The image reading method is:
A detection step of detecting a tip of the recording medium that is placed and transported at the placement position;
A reading operation start position setting step for setting the reading operation start position based on the position correspondence information acquired by the position correspondence information acquisition means when the leading edge of the recording medium is detected in the detection step;
Including
The detection step and the reading operation start position setting step are performed before the reading control step.

  According to the present invention, there is an effect that an image in an appropriate range on a recording medium can be read more reliably.

It is a figure which shows schematic structure of an inkjet recording device. It is a perspective view of a conveyance part. It is a block diagram which shows the main function structures of an inkjet recording device. It is a figure explaining the area | region where reading by an image reading part is performed. 6 is a flowchart illustrating a control procedure of reading operation start position setting processing. It is a flowchart which shows the control procedure of an image reading process. 10 is a flowchart illustrating a control procedure of a reading operation start position setting process according to the second embodiment. 10 is a flowchart illustrating a control procedure of image reading processing according to the second embodiment.

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

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

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

  The image recording unit 20 includes a conveyance unit 21 (conveyance unit), a delivery unit 22, a heating unit 23, a head unit 24 (recording unit), a fixing unit 25, a detection unit 26 (detection unit), and an image reading unit. It has a unit 27 (reading unit), a delivery unit 28, a reversing unit 29 (reversing unit), and the like.

FIG. 2 is a perspective view of the transport unit 21.
The transport unit 21 places and holds the recording medium P at a predetermined mounting position on the transport surface 211a (outer peripheral curved surface) of the cylindrical transport drum 211 (transport member), and the transport drum 211 is the drawing in FIG. The recording medium P rotates in the direction of the rotation of the conveyance drum 211 (hereinafter referred to as the conveyance direction) by rotating around the rotation axis (cylindrical axis) extending in the direction perpendicular to the width (cylinder direction). Carrying the carrying operation. The transport drum 211 includes a claw portion 212 and an intake portion 213 for holding the recording medium P on the transport surface 211a.

  The claw portion 212 includes a position defining portion 212a that defines a placement position on the transport drum 211, and an end portion of the recording medium P whose position (the downstream end in the transport direction) is defined by the position defining portion 212a. And a holding portion 212b that holds the toner between the transfer drum 211 and the transfer drum 211. The recording medium P is placed at a predetermined placement position whose tip is defined by the position defining unit 212a. In addition, since the end portion of the recording medium P is sandwiched between the sandwiching portion 212b and the surface of the transport drum 211, occurrence of a problem that the recording medium P is displaced from the mounting position is suppressed. With such a configuration, the error in the mounting position of the recording medium P is suppressed to about several tens of μm. Further, as shown in FIG. 1, the claw portions 212 are provided at three places where the intervals in the conveyance direction are equal in the conveyance drum 211. Accordingly, the transport unit 21 can place and transport the recording medium P on three different predetermined placement positions on the transport drum 211.

  The suction unit 213 sucks gas into the transport drum 211 through the plurality of suction holes provided in the transport surface 211a of the transport drum 211 along which the recording medium P held by the claw unit 212 is aligned. Has a suction force generator (not shown) (for example, an air pump or a fan) that generates a suction force. That is, the suction unit 213 sucks the recording medium P so as to be along the transport surface 211 a of the transport drum 211 by the suction force generated by the suction from the suction holes.

  The transport unit 21 includes a transport drum motor (not shown) for rotating the transport drum 211, and rotates by an angle proportional to the rotation amount of the transport drum motor. In FIG. 2, a part of the recording medium P is turned up from the conveying surface 211 a of the conveying drum 211, but this is for the purpose of illustrating the intake holes. During the conveyance, the entire recording medium P is held along the conveyance surface 211 a of the conveyance drum 211.

Further, the transport unit 21 includes a rotary encoder 52 (movement detection unit) attached to the transport drum 211. The rotary encoder 52 outputs a pulse signal (detection signal) to the control unit 40 every time the transport drum 211 rotates by a predetermined angle. The configuration of the rotary encoder 52 is not particularly limited. For example, a code wheel that is provided with a plurality of slits arranged on a predetermined circumference and rotates with the transport drum 211, and light is applied to the slits of the code wheel. And a light receiving unit that detects light emitted from the light emitting unit and passed through the slit, and outputs a pulse signal based on the detection result of the light by the light receiving unit to the control unit 40. Here, for example, the pulse signal is output at the rising and falling timings in each of two rectangular groups (A phase and B phase) having the same period as the light receiving period of the light passing through the slit and having a phase difference of 90 degrees from each other. Can be. In such a configuration, the rotation direction of the transport drum 211 can also be detected from the phases of the A phase and the B phase.
In addition, the rotary encoder 52 outputs a reference pulse signal to the control unit 40 once for each rotation of the transport drum 211. The controller 40 can acquire the position of the transport drum 211 based on the count value of the number of pulse signals input after the reference pulse signal is input. In the present embodiment, the count value forms position correspondence information corresponding to the position of the transport drum 211 corresponding to the transport operation of the transport unit 21.

  The delivery unit 22 delivers the recording medium P conveyed by the medium supply unit 12 of the paper feeding unit 10 to the conveyance drum 211. The delivery unit 22 is provided at a position between the medium supply unit 12 and the conveyance drum 211 of the paper supply unit 10, and picks up one end of the recording medium P conveyed from the medium supply unit 12 by the swing arm unit 221. Then, it is delivered to the transport drum 211 via the delivery drum 222.

  The heating unit 23 is provided between the arrangement position of the transfer drum 222 and the arrangement position of the head unit 24, and the recording medium P conveyed by the conveyance drum 211 has a temperature within a predetermined temperature range. Heat P. The heating unit 23 includes, for example, an infrared heater and energizes the infrared heater based on a control signal supplied from the CPU 41 (FIG. 3) to cause the infrared heater to generate heat.

  The head unit 24 performs a recording operation for recording an image by ejecting ink on the recording medium P conveyed by the conveying drum 211 in accordance with image data. The head unit 24 is arranged at a predetermined distance with respect to the transport surface 211a with the ink discharge surface facing the transport surface 211a of the transport drum 211. In the ink jet recording apparatus 1 of the present embodiment, four head units 24 respectively corresponding to four color inks of yellow (Y), magenta (M), cyan (C), and black (K) are transported in the recording medium P. They are arranged so as to be arranged at predetermined intervals in the order of Y, M, C, and K colors from the upstream side.

Each head unit 24 has a plurality of (for example, four) recordings in which a plurality of recording elements are arranged in a direction intersecting the conveyance direction of the recording medium P (in this embodiment, a direction orthogonal to the conveyance direction, ie, the width direction). A head 242 (FIG. 3) and a recording head drive unit 241 (FIG. 3) for driving the recording head 242 are provided.
Each of the recording elements provided in the recording head 242 includes a pressure chamber for storing ink, a piezoelectric element provided on a wall surface of the pressure chamber, and a nozzle. In this recording element, when a drive signal for deforming the piezoelectric element is input, the pressure chamber is deformed by the deformation of the piezoelectric element and the pressure in the pressure chamber changes, and the ink ejects ink from the nozzles communicating with the pressure chamber. Discharge operation is performed. The amount of ink ejected from the recording element can be adjusted by changing the amplitude of the voltage of the drive signal.
In each head unit 24, the arrangement ranges in the width direction are partially overlapped with each other in such a positional relationship that a plurality of recording heads 242 are continuously connected in the width direction so that ink can be ejected from the recording elements. The line head is configured in a staggered pattern. Here, the arrangement range of the recording elements included in the head unit 24 in the width direction covers the width in the width direction of the area in which the image can be recorded in the recording medium P conveyed by the conveyance unit 21. The head unit 24 is used at a fixed position during image recording, and sequentially ejects ink at different intervals (conveyance direction intervals) to different positions in the conveyance direction according to the conveyance of the recording medium P. Record an image using the single pass method.

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

  The fixing unit 25 includes a light emitting unit disposed across the width of the conveyance drum 211 and irradiates the recording medium P placed on the conveyance drum 211 with energy rays such as ultraviolet rays from the light emission unit. Then, a fixing operation is performed in which the ink discharged on the recording medium P is cured and fixed. The light emitting unit of the fixing unit 25 is arranged to face the conveyance surface 211a on the downstream side of the arrangement position of the head unit 24 and the upstream side of the arrangement position of the delivery drum 281 of the delivery unit 28 in the conveyance direction.

  The detection unit 26 is provided at a position between the ink fixing position by the fixing unit 25 and the position where the transfer drum 281 is disposed, and detects the leading end of the recording medium P conveyed by the conveyance drum 211 and outputs a predetermined detection signal. Output to the control unit 40. The detection unit 26 according to the present embodiment includes a light detection element that detects the intensity of light reflected at a position facing the detection unit 26 in the transport surface 211a, and when the leading edge of the recording medium P reaches the facing position. What detects the front-end | tip of the recording medium P by the change of received light intensity can be used. The configuration of the detection unit 26 and the detection method are not limited to this. For example, the detection unit 26 detects the tip of the recording medium P by another optical method, or physically contacts the tip of the recording medium P. A detection method may be used.

The image reading unit 27 is arranged so as to be able to read the conveyance surface 211a and the surface of the recording medium P on the conveyance surface 211a at a position between the detection position by the detection unit 26 and the arrangement position of the transfer drum 281 in the conveyance direction. Then, a reading operation for reading an image recorded on the recording medium P conveyed by the conveying drum 211 in a predetermined reading area is performed, and imaging data of the image is output to the control unit 40. The reading operation by the image reading unit 27 is started at the timing when the transport drum 211 moves to the reading operation start position corresponding to each of the three placement positions of the recording medium P.
In the present embodiment, the image reading unit 27 has a light source that emits light to the recording medium P conveyed by the conveying drum 211 and an image sensor that detects the intensity of reflected light of the light incident on the recording medium P. Line sensors arranged in a direction. Specifically, in the line sensor, three rows of image pickup devices each including image pickup devices arranged in the width direction are provided, and R (red), G (green), and B of the incident light are provided by the image pickup devices of each image pickup device row. A signal corresponding to the intensity of the wavelength component of (blue) is output. Imaging elements corresponding to R, G, and B are, for example, R, G, or B in a light receiving portion of a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor that includes a photodiode as a photoelectric conversion element. A filter in which a color filter that transmits light having a wavelength component of is arranged can be used.
The signal output from the line sensor is subjected to current-voltage conversion, amplification, noise removal, analog-digital conversion, and the like in an analog front end (not shown), and is output to the control unit 40 as imaging data indicating the luminance value of the read image.
Note that the configuration of the image reading unit 27 is not limited to this. For example, an area sensor may be used instead of the line sensor.

  The delivery unit 28 includes a belt loop 282 having a ring-shaped belt supported on the inside by two rollers, and a cylindrical transfer drum 281 that transfers the recording medium P from the transport drum 211 to the belt loop 282. The recording medium P transferred from the transfer drum 211 onto the belt loop 282 by the transfer drum 281 is transferred by the belt loop 282 and sent to the paper discharge unit 30.

The reversing unit 29 operates under the control of the CPU 41 when reversing the front and back of the recording medium P. The reversing unit 29 reverses the front and back of the recording medium P delivered from the transfer drum 281 and delivers it to the transport unit 21, and then on the transport drum 211. Place on any of the three placement positions. The reversing unit 29 includes a first drum 291, a second drum 292, and a belt loop 293.
In the reversing unit 29, the recording medium P is transferred from the transfer drum 281 rotating in the clockwise direction in FIG. 1 to the first drum 291 rotating in the counterclockwise direction in FIG. 1, and then rotated in the clockwise direction in FIG. It is sequentially delivered to the second drum 292 and the belt loop 293 that rotates counterclockwise. When the rear end of the recording medium P reaches the vicinity of the nip portion between the second drum 292 and the belt loop 293, the rotation direction of the belt loop 293 is changed to the clockwise direction in FIG. It is placed on one of the three placement positions on the transport drum 211 on the upstream side. The recording medium P placed on the conveyance drum 211 by the reversing unit 29 is held again on the conveyance drum 211 in a state where the surface on which the image is formed is in contact with the conveyance surface 211a.
Note that the configuration of the reversing unit 29 is not limited to the above, and can be appropriately selected from various configurations that can be transferred to the transport unit 21 by inverting the front and back of the recording medium P.

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

FIG. 3 is a block diagram showing the main functional configuration of the inkjet recording apparatus 1.
The inkjet recording apparatus 1 includes a control unit 40, a heating unit 23, a head unit 24 having a recording head driving unit 241 and a recording head 242, a fixing unit 25, a detection unit 26, an image reading unit 27, and a conveyance drive. The conveyance part 21 which has the part 51 and the rotary encoder 52, the operation display part 53, the input-output interface 54, the bus | bath 55, etc. are provided.

  The control unit 40 includes a CPU 41 (Central Processing Unit) (reading control unit, recording control unit, reading operation start position setting unit), a RAM 42 (Random Access Memory), a ROM 43 (Read Only Memory), and a storage unit 44 (storage unit). Have.

  The CPU 41 reads various control programs and setting data stored in the ROM 43, stores them in the RAM 42, executes the programs, and performs various arithmetic processes. The CPU 41 controls the overall operation of the inkjet recording apparatus 1. For example, the CPU 41 operates each unit of the image recording unit 20 based on the image data stored in the storage unit 44 to record an image on the recording medium P. Further, the CPU 41 acquires the position of the transport drum 211 based on the number of pulse signals output from the rotary encoder 52. In the present embodiment, the rotary encoder 52 and the CPU 41 constitute position correspondence information acquisition means.

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

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

The storage unit 44 includes a print job (image recording command) input from the external apparatus 2 via the input / output interface 54 and image data of the print job, test image data, and image reading unit 27. Imaging data is stored. Further, the storage unit 44 stores reading operation start position data 44a (reading operation start position information) indicating the above-described reading operation start position where the reading operation by the image reading unit 27 is started. As the storage unit 44, for example, an HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may be used in combination.
In the reading operation start position data 44 a described above, the position of the conveyance drum 211 when the reading operation by the image reading unit 27 is started is output from the rotary encoder 52 for each of the three placement positions of the conveyance drum 211. This is indicated by the aforementioned count value of the number of pulse signals.

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

  The transport drive unit 51 supplies a drive signal to the transport drum motor of the transport drum 211 based on a control signal supplied from the CPU 41 to rotate the transport drum 211 at a predetermined speed and timing. Further, the transport driving unit 51 supplies a drive signal to a motor for operating the medium supply unit 12, the delivery unit 22, and the delivery unit 28 based on a control signal supplied from the CPU 41, so that the recording medium P is transported. Supply to the drum 211 and discharge from the transport drum 211 are performed. Further, the transport driving unit 51 operates the first drum 291, the second drum 292, and the belt loop 293 of the reversing unit 29 based on the control signal supplied from the CPU 41, and the reversing unit 29 controls the front and back of the recording medium P. Invert.

  The operation display unit 53 includes a display device such as a liquid crystal display or an organic EL display, and an input device such as an operation key or a touch panel arranged on the screen of the display device. The operation display unit 53 displays various information on the display device, converts a user input operation to the input device into an operation signal, and outputs the operation signal to the control unit 40.

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

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

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

Next, an image reading operation in the inkjet recording apparatus 1 will be described.
In the ink jet recording apparatus 1 of the present embodiment, detection of ink ejection defects of the recording elements and adjustment of the ink ejection operation on the recording medium P at a predetermined recording frequency or in response to an input operation to the operation display unit 53 by the user. A test image for recording is recorded. The test image recorded on the recording medium P is read by the image reading unit 27, and ink discharge failure is detected and ink discharge operation is adjusted based on the obtained imaging data.
Examples of the test image recorded on the recording medium P include a missing position specifying chart including lines extending in the transport direction recorded by each of the plurality of recording elements included in the head unit 24, and a plurality of recording heads in the head unit 24. For example, there is a gray chart (FIG. 4) composed of gradation images for detecting the variation in the ink discharge amount between 242.

In the imaging data obtained by reading the missing position specifying chart as the test image by the image reading unit 27, when there is a missing line or a line that is not recorded at an appropriate position corresponding to the recording element, The corresponding recording element can be identified as a defective recording element. When a defective recording element is identified, for example, the ink from the defective recording element is not ejected, and the ink that should be ejected by the defective recording element is ejected from recording elements around the defective recording element. Complementary processing is set for complementation by increasing the ink amount.
In addition, in the imaging data obtained by reading the gray chart as the test image by the image reading unit 27, when a density difference is detected in the gradation images recorded by the plurality of recording heads 242, the density difference is determined. Accordingly, by adjusting the amplitude of the voltage of the drive signal supplied to the recording element of each recording head 242, density variation in the recorded image is suppressed.

The test image reading operation by the image reading unit 27 is performed as follows.
In the inkjet recording apparatus 1 of the present embodiment, as described above, the recording medium P is placed on any of the three placement positions on the transport drum 211, and a maximum of three recording media P are on the transport drum 211. It is placed at three placement positions and conveyed. When the recording medium P is delivered from the delivery unit 22 onto the transport drum 211 and placed at the placement position on the transport drum 211, placement position data indicating the placement position is transferred from the transport drive unit 51 to the control unit 40. Is output. Then, when the placement position data indicates that the recording medium P is placed at any placement position and a test image is recorded on the recording medium P, the placement position data is previously set according to the placement position. When the conveyance drum 211 moves to the set reading operation start position, the reading operation by the image reading unit 27 is started, whereby a predetermined relative position (reading start position) with respect to the leading end of the recording medium P in the conveyance direction. The reading operation is started.
That is, when the recording medium P is held and conveyed at any of the three placement positions on the conveyance drum 211 and a test image is recorded by the head unit 24, the reading operation start position data stored in the storage unit 44 is stored. 44a, the reading operation start position corresponding to the mounting position on which the recording medium P is mounted is referred to, and is output from the rotary encoder 52 when the transport drum 211 moves to the reading operation start position. When the count value of the number of pulse signals coincides with the number indicated by the data of the reading operation start position, the image reading operation by the image reading unit 27 is started.

FIG. 4 is a diagram for explaining an area where reading by the image reading unit 27 is performed.
FIG. 4 shows a recording medium P placed at a predetermined placement position on the transport drum 211 and having a test image 60 recorded in a rectangular image recording area Ra. Here, it is assumed that the end of the image recording area Ra on the downstream side in the transport direction is located at a distance D2 with respect to the front end of the recording medium P.
4 shows a reading start position S on the conveyance surface 211a where reading by the image reading unit 27 is started, and a reading region Rb where reading by the image reading unit 27 is performed. The reading area Rb is a rectangular area including the image recording area Ra with the reading start position S as an end on the downstream side in the transport direction.
When the conveyance drum 211 rotates, the image reading unit 27 reaches the reading position where the reading start position S on the conveyance surface 211 a faces the line sensor of the image reading unit 27 and is read by the image reading unit 27. The reading operation is started. Therefore, the reading operation start position corresponding to each placement position in the reading operation start position data 44 a described above is the position of the transport drum 211 when the reading start position S coincides with the reading position by the image reading unit 27. After the start of the reading operation, the image reading unit 27 repeats imaging by the line sensor at an appropriate timing according to the rotation of the transport drum 211 to read the range of the reading region Rb and output the imaging data to the control unit 40. To do.

Here, in the inkjet recording apparatus 1, the recording medium P is placed at the placement position in a state where the position of the tip is defined by the claw portion 212, so that the conveyance between the tip of the recording medium P and the reading start position S is performed. The relative positional relationship with respect to the direction is constant as long as the recording medium P is properly placed. Specifically, in FIG. 4, the reading start position S is a position of a distance D1 from the leading end of the recording medium P to the upstream side in the conveyance direction, and the interval Δ in the conveyance direction between the reading start position S and the image recording area Ra is , D2-D1. These distances D1, D2 and the interval Δ have the same value for the recording medium P placed at the same placement position. The reading start position S is set as upstream as possible in the transport direction within a range that does not overlap the image recording area Ra when the downstream end position of the image recording area Ra varies.
As described above, in the inkjet recording apparatus 1 of the present embodiment, when the reading start position S coincides with the reading position of the image reading unit 27, that is, when the transport drum 211 moves to the reading operation start position, the image reading unit 27 By starting the reading operation, reading is started from a position of a predetermined relative distance D1 with respect to the leading end of the recording medium P.

Next, a method for setting the reading operation start position will be described.
In the ink jet recording apparatus 1, the position of the claw portion 212 at the three placement positions, that is, the position of the tip of the recording medium P placed at the placement position is the transport direction on the transport surface 211 a of the transport drum 211, etc. Designed to be spaced. Therefore, if the attachment positions of the claw portions 212 at the three placement positions are as designed, the reading operation starts for each position where the transport drum 211 rotates 120 degrees corresponding to the design attachment positions of the claw portions 212. By setting the position, the reading operation can be started from an appropriate position.

  However, when the inkjet recording apparatus 1 is produced, the attachment position of the claw portion 212 may deviate from the designed position. When the attachment position of the claw portion 212 is shifted, the recording medium P is placed at the placement position in a state where the position of the leading edge is shifted in the transport direction every time according to the displacement, and thus the claw portion 212. If the reading operation start position is determined based on the designed mounting position, the distance between the leading end of the recording medium P and the reading start position S is deviated from a predetermined value every time. That is, when reading the recording medium P placed at the placement position where the attachment position of the claw portion 212 is shifted, the distance D1 and the interval Δ in FIG. 4 are different from those at the time of reading related to other placement positions. Become. Depending on the size of the positional deviation of the claw 212, the interval Δ cannot be secured, and the reading start position S may overlap the image recording area Ra.

  Therefore, in the present embodiment, when the inkjet recording apparatus 1 is produced or shipped, the position of the front end of the recording medium P that is placed with the position defined by the claw portion 212 is detected at each placement position. Based on the detection result, a reading operation start position corresponding to the placement position is set. The setting of the reading operation start position is performed by a reading operation start position setting operation by the inkjet recording apparatus 1. Hereinafter, the reading operation start position setting operation will be described.

In the reading operation start position setting operation, first, the recording medium P is placed at one placement position of the transport drum 211 and transported toward the detection position by the detection unit 26. When the position of the front end of the recording medium P reaches the detection position by the detection unit 26, the front end is detected by the detection unit 26, and the position of the transport drum 211 at the time of detection (hereinafter referred to as the front end detection position). To be acquired.
Then, based on the acquired tip detection position, the reading operation start position related to the setting target placement position is set. That is, the position of the transport drum 211 when rotated by a predetermined angle from the front end detection position, specifically, the angle corresponding to the interval from the detection position by the detection unit 26 to the reading position of the image reading unit 27 is detected. The position of the transport drum 211 when rotated from the tip detection position by the sum of the angle corresponding to the distance D1 shown in FIG. 4 is set as the reading operation start position corresponding to the setting target mounting position.

  In this way, even when the attachment position of the claw part 212 is deviated from the design position by detecting the front end of the recording medium P whose position is defined in the claw part 212 and setting the reading operation start position, Reading can be started from a desired relative position with respect to the front end of the recording medium P.

  Next, a control procedure by the CPU 41 of the reading operation start position setting process related to the reading operation start position setting operation will be described.

FIG. 5 is a flowchart showing a control procedure of the reading operation start position setting process.
Prior to the start of the reading operation start position setting process, the CPU 41 outputs a drive signal from the conveyance drive unit 51 to the conveyance drum motor of the conveyance drum 211 to start the rotation operation of the conveyance drum 211, and from the rotary encoder 52 to the control unit. The count of the number of pulse signals input to 40 is started. The count value is reset every time a reference pulse signal is input from the rotary encoder 52 to the control unit 40.

  When the reading operation start position setting process is started, the CPU 41 causes the motor that drives the medium supply unit 12 and the delivery unit 22 to output a drive signal from the transport drive unit 51 to carry out the recording medium P from the paper feed tray. It is placed at one placement position on the conveyance surface 211a of the conveyance drum 211 and is held by the claw portion 212 (step S101).

  The CPU 41 causes the detection unit 26 to detect the front end of the recording medium P, and acquires the position (front end detection position) of the transport drum 211 at the time of detection (step S102: detection step). That is, the CPU 41 first outputs a control signal to the detection unit 26 and starts the leading edge detection operation of the recording medium P by the detection unit 26. When the detection signal of the leading end of the recording medium P is output from the detection unit 26, the position of the transport drum 211 (the count value of the pulse signal input from the rotary encoder 52) at the timing when the detection signal is detected is the leading end. Obtained as a detection position and stored in the RAM 42.

  The CPU 41 sets the reading operation start position related to the setting target placement position based on the acquired tip detection position (step S103: reading operation start position setting step). That is, the CPU 41 detects the tip of the conveyance drum 211 by the sum of the angle corresponding to the interval from the detection position of the detection unit 26 to the reading position of the image reading unit 27 and the angle corresponding to the distance D1 shown in FIG. The position of the transport drum 211 when rotated from the position is set as a reading operation start position related to the setting target mounting position, and is stored in the storage unit 44 as reading operation start position data 44a.

When the processing in step S103 is completed, the CPU 41 causes the motor that drives the delivery unit 28 to output a driving signal from the transport driving unit 51 to discharge the recording medium P to the paper discharge unit 30 (step S104), and starts the reading operation. The position setting process is terminated.
The above reading operation start position setting process is performed for each of the three placement positions on the transport drum 211.

  Next, a control procedure performed by the CPU 41 for image reading processing related to recording and reading of a test image in the inkjet recording apparatus 1 will be described.

FIG. 6 is a flowchart showing the control procedure of the image reading process.
This image reading process is executed when a test image is recorded on the recording medium P, for example, at a preset frequency or in response to an input operation performed on the operation display unit 53 by the user. Prior to the start of the image reading process, the CPU 41 outputs a drive signal from the conveyance driving unit 51 to the conveyance drum motor of the conveyance drum 211 to start the rotation operation of the conveyance drum 211, and from the rotary encoder 52 to the control unit 40. The counting of the number of pulse signals input to is started. The count value is reset every time a reference pulse signal is input from the rotary encoder 52 to the control unit 40.

  When the image reading process is started, the CPU 41 causes the motor that drives the medium supply unit 12 and the delivery unit 22 to output a driving signal from the conveyance driving unit 51 to carry out the recording medium P from the paper feed tray 11 and convey the drum. It is placed at any placement position on 211 and held by the claw portion 212 of the transport drum 211 (step S201).

  The CPU 41 starts a recording operation by the head unit 24 when the transport drum 211 moves to an appropriate position according to the placement position, and records a test image on the recording medium P (step S202). Here, the CPU 41 supplies the image data of the test image stored in the storage unit 44 to the recording head driving unit 241, and the recording head driving unit 241 generates a drive waveform at an appropriate timing according to the rotation of the transport drum 211. A test image is recorded by outputting a voltage signal to the recording head 242. Further, the CPU 41 causes the transport unit 21 to transport the recording medium P to the position of the fixing unit 25 and causes the fixing unit 25 to fix the ink ejected onto the recording medium P.

  The CPU 41 causes the image reading unit 27 to start the reading operation at the start timing based on the reading operation start position corresponding to the placement position of the recording medium P and read the test image on the recording medium P (step S203: reading control step). ). That is, the CPU 41 refers to the reading operation start position data 44a stored in the storage unit 44, and acquires the reading operation start position corresponding to the mounting position on which the recording medium P is mounted. Then, the CPU 41 starts the reading operation by the image reading unit 27 at the timing when the conveyance drum 211 moves to the acquired reading operation start position, and the recording medium P is moved by a distance corresponding to the size of the reading region Rb in the conveyance direction. The reading operation is continued while being conveyed. In addition, the CPU 41 causes the image reading unit 27 to output imaging data of a test image.

  The CPU 41 causes the motor that drives the delivery unit 28 to output a drive signal from the transport drive unit 51 to discharge the recording medium P to the paper discharge unit 30 (step S204), and ends the image reading process.

As described above, the ink jet recording apparatus 1 according to the present embodiment has a transport unit that performs a transport operation of transporting the recording medium P by placing the recording medium P on a predetermined mounting position on the transporting drum 211 that moves around. 21, a head unit 24 that records an image by ejecting ink onto a recording medium P that is moved by a conveying operation, and an image reading unit that performs a reading operation of reading an image recorded on the recording medium P by the head unit 24 27 and a CPU 41, and the CPU 41 acquires a count value (position correspondence information) of the number of pulse signals output from the rotary encoder 52 corresponding to the position corresponding to the circular movement of the transport drum 211 (position correspondence information). Corresponding information acquisition unit), the start timing of the reading operation by the image reading unit 27 based on the count value acquired by the position corresponding information acquisition unit Please be (read control means).
Thereby, the reading operation by the image reading unit 27 can be started without detecting the leading end of the recording medium P placed and conveyed at a predetermined placement position. Therefore, there is no deviation in the reading start timing due to the fact that the leading edge of the recording medium P cannot be detected properly, so that the reading operation can be started stably at an appropriate start timing. That is, an image in an appropriate range on the recording medium P can be read from a desired relative position with respect to the leading end of the recording medium P more reliably. Further, it is possible to determine the start timing of the reading operation using the position correspondence information (the count value in the present embodiment) corresponding to the position of the transport drum 211, and in the determination of the start timing of the reading operation, Since processing related to leading edge detection is not necessary, the reading operation by the image reading unit 27 can be started at an appropriate timing by simple processing.

  In addition, the read operation start timing is determined as a timing at which the position of the transport drum 211 coincides with a read operation start position set in advance according to the placement position, and thus the recording medium P placed at the placement position. The reading operation by the image reading unit 27 can be started stably every time from a predetermined relative position with respect to the tip.

  The reading operation start position is the position of the transport drum 211 when the leading end of the recording medium P placed at the placement position and the position where the image reading unit 27 performs reading has a predetermined positional relationship in the transport direction. Position. In this way, the reading operation start position is set based on the positional relationship with the leading end of the recording medium P placed at the placement position, so that the placement position is provided on any position on the transport drum 211. (For example, even when the placement position deviates from the design value), the reading operation by the image reading unit 27 is stably performed from a predetermined relative position with respect to the front end of the recording medium P each time. Can be started. As a result, the image recording area Ra in which the image to be read is recorded and the reading start position S are not shifted due to an error from the design value of the mounting position. An interval Δ between the region Ra and the reading start position S can be determined, and the interval Δ can be set smaller. Thereby, the size of the imaging data related to the reading result by the image reading unit 27 can be further reduced.

  In addition, the inkjet recording apparatus 1 includes a storage unit 44 that stores reading operation start position data 44a indicating a reading operation start position, and the start timing of the reading operation is indicated by the position of the transport drum 211 indicated by the reading operation start position data 44a. The timing coincides with the reading operation start position. According to such a configuration, by referring to the reading operation start position data 44a, the reading operation can be started at an appropriate start timing by an easy process.

  In addition, the inkjet recording apparatus 1 includes a detection unit 26 that detects the leading end of the recording medium P that is placed and conveyed at the mounting position, and the CPU 41 detects when the leading end of the recording medium P is detected by the detection unit 26. The reading operation start position is set based on the count value of the number of pulse signals output from the rotary encoder 52, and the reading operation start position data 44a is stored in the storage unit 44 (reading operation start position setting means). According to such a configuration, the reading operation start position can be set in the inkjet recording apparatus 1.

  A plurality of placement positions are set on the transport drum 211. Thereby, even when the recording medium P is placed at any of the plurality of placement positions, the image can be easily read from a desired relative position with respect to the leading end of the recording medium P.

  Further, the rotary encoder 52 and the CPU 41 as position correspondence information acquisition means acquire the count value of the number of the pulse signals indicating the amount of movement of the transport drum 211 from the predetermined reference position in the transport operation. According to such a configuration, it is possible to easily read an image from a desired relative position with respect to the front end of the recording medium P based on the position correspondence information indicating the movement amount of the transport drum 211 that can be acquired by simple processing. .

  Further, of the rotary encoder 52 and the CPU 41 serving as position correspondence information acquisition means, the rotary encoder 52 outputs a pulse signal for every movement of the transport drum 211 by a predetermined angle, and the CPU 41 outputs the pulse signal from the output pulse signal. Get the count value. Thereby, the position correspondence information can be easily acquired and the position of the transport drum 211 can be specified by a simple process of counting the number of pulse signals.

  Further, since the position correspondence information acquisition means includes the rotary encoder 52, the position correspondence information is easily obtained by a simple process of counting the number of pulse signals output from the rotary encoder 52. Can be specified.

  Further, the transport unit 21 has a position defining unit 212a of a claw unit 212 that defines a placement position on the transport drum 211, and the recording medium P has at least one of the front end and the rear end of the recording medium P defined by the position. It is placed and transported at the placement position defined by the section 212a. Thereby, the recording medium P can be easily placed at a predetermined placement position on the transport drum 211.

  In addition, the transport unit 21 includes a clamping unit 212 b of the claw unit 212 that clamps the end of the recording medium P, at least one of the leading end and the trailing end of which is stopped by the position defining unit 212 a, with the transport drum 211. Thereby, it is possible to suppress the occurrence of a problem that the position of the recording medium P placed at the placement position is shifted during the transport operation.

  The transport unit 21 includes a cylindrical transport drum 211. The recording medium P is placed on the outer peripheral curved surface of the transport drum 211, and the transport operation is performed by rotating the transport drum 211 around the cylindrical shaft. Do. According to such a configuration, since the transport operation by the transport unit 21 can be performed without deforming the transport drum 211, the recording medium P is held at the mounting position regardless of the position of the transport drum 211. I can keep it. For this reason, the degree of freedom of the position where the recording medium P is placed on or discharged from the transport drum 211 can be increased.

  Further, the image reading method of the present embodiment includes a transport unit 21 that performs a transport operation of transporting the recording medium P by placing the recording medium P on a predetermined mounting position on the transporting drum 211 that moves around, A head unit 24 that records an image by ejecting ink onto the recording medium P that is moved by the operation; an image reading unit 27 that performs a reading operation of reading an image recorded on the recording medium P by the head unit 24; Inkjet recording comprising: a CPU 41 (position correspondence information acquisition means) that obtains a count value (position correspondence information) of the number of pulse signals output from the rotary encoder 52 corresponding to a position according to the conveying operation of the drum 211 In the image reading method of the apparatus, the start timing of the reading operation by the image reading unit 27 is determined by the number of the pulse signals acquired by the CPU 41. Controlled based on the count value comprising the reading control step. According to such a method, an image in an appropriate range on the recording medium P can be read from a desired relative position with respect to the front end of the recording medium P more reliably.

  In the image reading method of the present embodiment, the start timing is determined as a timing at which the position of the transport drum 211 coincides with a reading operation start position set in advance according to the placement position. A detection step for detecting the leading end of the recording medium P placed and conveyed at the mounting position, and a count value of the number of pulse signals output from the rotary encoder 52 when the leading end of the recording medium P is detected in the detection step. A reading operation start position setting step for setting a reading operation start position based on the detection operation, and the detection step and the reading operation start position setting step are performed before the reading control step. Accordingly, the reading operation by the image reading unit 27 can be started from a predetermined relative position with respect to the leading end of the recording medium P stably each time.

(Second Embodiment)
Next, a second embodiment of the ink jet recording apparatus of the present invention will be described. The present embodiment is different from the above-described embodiment in that a reading operation start position is set for each of the placement positions with respect to each of the front surface and the back surface of the recording medium P. Below, it demonstrates centering on difference with the said embodiment.

  In the present embodiment, when the reading operation start position data 44a stored in the storage unit 44 performs a reading operation on the surface (one surface) of the recording medium P at the three placement positions of the transport drum 211. And the reading operation start position data when the reading operation is performed on the back surface (the other surface) of the recording medium P, respectively. In other words, the reading operation start position data 44a includes data for a total of six reading operation start positions, two for every three placement positions. Hereinafter, the surface on which the image is first recorded out of the two surfaces of the recording medium P is referred to as a surface.

  In the present embodiment, when a test image to be read is recorded on the surface of the recording medium P, the surface of the two reading operation start positions related to the mounting position on which the recording medium P is mounted is applied to the surface. A reading operation start position corresponding to the reading operation is referred to, and when the transport drum 211 moves to the reading operation start position, the reading operation by the image reading unit 27 is started. Further, when the test image to be read is recorded on the back surface of the recording medium P, the reading operation for the back surface of the two reading operation start positions related to the mounting position on which the recording medium P is mounted is performed. The corresponding reading operation start position is referred to, and when the transport drum 211 moves to the reading operation start position, the reading operation by the image reading unit 27 is started.

As described above, as an example of the case where it is desirable to set the reading operation start position separately for the front and back of the recording medium P, between the time of reading the image on the front surface of the recording medium P and the time of reading the image on the back surface, The recording medium P contracts or expands due to the influence of the ink discharged on the front and back of the recording medium P into the recording medium P and the heat applied when the ink is fixed. The case where the distance with the edge part of the conveyance direction downstream side of area | region Ra differs in front and back is mentioned.
Hereinafter, a method for setting the reading operation start position in such a case will be described.

  In the setting of the reading operation start position in this case, first, a test image is recorded by the head unit 24 on the recording medium P placed at the placement position. Here, the test image to be recorded has a width direction indicating the end position so that the end position on the downstream side in the transport direction of the image recording area Ra can be easily determined from the image data of the test image. Preferably a line is included. When the test image is recorded, the leading end detection position of the transport drum 211 when the leading end of the recording medium P placed at the placement position is detected by the detection unit 26 is acquired as in the above embodiment. The reading operation by the image reading unit 27 is started when the transport drum 211 moves to the temporary reading operation start position set corresponding to the mounting position of the recording medium P, and the recording medium P and the recording medium The test image recorded in P is read by the image reading unit 27. Here, the provisional reading operation start position is set to a position where the leading edge of the recording medium P and the test image can be read with a margin even if there is an error in the attachment position of the claw portion 212.

  Then, by analyzing the imaging data of the obtained test image, a distance D2 from the front end of the recording medium P to the downstream end of the image recording area Ra where the test image is recorded on the recording medium P is calculated. The reading operation start position is set based on the calculated distance D2 and the tip detection position. That is, the distance D1 is calculated by subtracting the predetermined distance Δ from the distance D2, and the conveyance drum 211 corresponds to the angle corresponding to the distance from the detection position by the detection unit 26 to the reading position of the image reading unit 27 and the distance D1. The position of the transport drum 211 when it is rotated from the tip detection position by the sum of the angle to be set is set as the reading operation start position related to the surface corresponding to the placement position.

  Subsequently, the front and back of the recording medium P are reversed by the reversing unit 29, and the reading operation start position is set on the back surface of the recording medium P by the same method as the front surface. Here, when the test image recorded on the back surface is read by the image reading unit 27, the recording medium P is deformed from the time of reading the test image on the front surface. For this reason, the distance D2 between the front end of the recording medium P and the downstream end of the image recording area Ra on the back surface is different from the distance D2 related to the front surface. Based on the distance D2 related to the back surface, a distance D1 (= D2−Δ) is calculated, and a reading operation start position is set. The relative position from the front end of the medium P is adjusted, and reading can be performed from a position downstream of the image recording area Ra by a predetermined distance Δ from the downstream side as well.

  The amount of deformation due to the shrinkage or expansion of the recording medium P described above may vary depending on the recorded test image. For this reason, the reading operation start position relating to the front and back of the recording medium P for each placement position may be set for each test image to be recorded.

Next, a control procedure by the CPU 41 of the reading operation start position setting process according to the present embodiment will be described.
FIG. 7 is a flowchart illustrating a control procedure of the reading operation start position setting process according to the present embodiment.

  When the reading operation start position setting process is started, the CPU 41 operates each part of the paper feeding unit 10 and the image recording unit 20 to place the recording medium P at any placement position on the transport surface 211 a of the transport drum 211. It is placed and held by the claw portion 212 (step S301).

  The CPU 41 starts a recording operation by the head unit 24 when the transport drum 211 moves to an appropriate position according to the placement position, and records a test image on the surface of the recording medium P (step S302). Further, the CPU 41 causes the transport unit 21 to transport the recording medium P to the position of the fixing unit 25 and causes the fixing unit 25 to fix the ink ejected onto the recording medium P.

  The CPU 41 causes the detection unit 26 to detect the front end of the recording medium P, and acquires the position (front end detection position) of the transport drum 211 at the time of detection (step S303: detection step).

  The CPU 41 starts the reading operation by the image reading unit 27 when the transport drum 211 moves to the temporary reading operation start position, and the test recorded on the leading end of the recording medium P and the recording medium P by the image reading unit 27. The image is read, and the imaging data is stored in the storage unit 44 (step S304).

  The CPU 41 sets the reading operation start position related to the surface by the above-described method based on the reading result by the image reading unit 27 and the leading edge detection position acquired in step S303, and stores it in the storage unit 44 as reading operation start position data 44a. Store (step S305: reading operation start position setting step).

  The CPU 41 outputs a control signal from the transport driving unit 51 to the reversing unit 29, reverses the front and back of the recording medium P by the reversing unit 29, and places them on the same mounting position on the transport drum 211. (Step S306).

  The CPU 41 causes the head unit 24 to record a test image on the recording medium P whose front and back sides are reversed (step S307), acquires the leading edge detection position (step S308: detection step), and the image reading unit 27 causes the recording medium P to be recorded. The leading edge and the test image of the image data are read and the imaging data is stored in the storage unit 44 (step S309). Based on the imaging data and the leading edge detection position, the reading operation start position related to the back surface is set and the reading operation start position data 44a. Is stored in the storage unit 44 (step S310: reading operation start position setting step). Since the processing from step S307 to step S310 is the same as the processing from step S302 to step S305 except that the processing is performed on the back surface of the recording medium P, description thereof is omitted.

When the processing in step S310 is completed, the CPU 41 causes the motor that drives the delivery unit 28 to output a drive signal from the transport driving unit 51 to discharge the recording medium P to the paper discharge unit 30 (step S311), and the reading operation start position. The setting process is terminated.
The above reading operation start position setting process is performed for each of the three placement positions on the transport drum 211.

FIG. 8 is a flowchart showing the control procedure of the image reading process of this embodiment.
This image reading process is executed when test images are recorded on the front and back surfaces of the recording medium P, for example, at a preset frequency or in response to an input operation on the operation display unit 53 by the user.

  When the image reading process is started, the CPU 41 operates each part of the paper feeding unit 10 and the image recording unit 20 to place the recording medium P on any placement position on the conveyance surface 211 a of the conveyance drum 211. And held by the claw portion 212 (step S401). Further, the CPU 41 causes the head unit 24 to eject ink, records a test image on the surface of the recording medium P, and fixes the ejected ink to the fixing unit 25 (step S402).

  The CPU 41 starts the reading operation by the image reading unit 27 at the start timing based on the reading operation start position corresponding to the placement position of the recording medium P, and reads the test image recorded on the surface of the recording medium P (step S403). : Reading control step). That is, the CPU 41 refers to the reading operation start position data 44a stored in the storage unit 44, and acquires the reading operation start position related to the surface corresponding to the mounting position on which the recording medium P is mounted. Then, the CPU 41 starts the reading operation by the image reading unit 27 at the timing when the conveyance drum 211 moves to the acquired reading operation start position, and the recording medium P is moved by a distance corresponding to the size of the reading region Rb in the conveyance direction. The reading operation is continued while being conveyed. In addition, the CPU 41 causes the image reading unit 27 to output imaging data of a test image.

  The CPU 41 outputs a control signal from the transport driving unit 51 to the reversing unit 29, reverses the front and back of the recording medium P by the reversing unit 29, and places them on the same mounting position on the transport drum 211. (Step S404). Further, the CPU 41 causes the head unit 24 to eject ink to record a test image on the back surface of the recording medium P, and fixes the ejected ink to the fixing unit 25 (step S405).

  The CPU 41 starts the reading operation by the image reading unit 27 at the start timing based on the reading operation start position corresponding to the placement position of the recording medium P, and reads the test image recorded on the back surface of the recording medium P (step S406). : Reading control step). That is, the CPU 41 refers to the reading operation start position data 44a stored in the storage unit 44, and acquires the reading operation start position related to the back surface corresponding to the mounting position on which the recording medium P is mounted. Then, the CPU 41 starts the reading operation by the image reading unit 27 at the timing when the conveyance drum 211 moves to the acquired reading operation start position, and the recording medium P is moved by a distance corresponding to the size of the reading region Rb in the conveyance direction. The reading operation is continued while being conveyed. In addition, the CPU 41 causes the image reading unit 27 to output imaging data of a test image.

  The CPU 41 outputs a drive signal from the transport drive unit 51 to the motor that drives the delivery unit 28 to discharge the recording medium P to the paper discharge unit 30 (step S407), and ends the image reading process.

As described above, the inkjet recording apparatus 1 according to the second embodiment includes the reversing unit 29 that reverses the front and back of the recording medium P placed on the transport drum 211 and places the recording medium P on the placement position. After the image is recorded by the head unit 24 on one surface of the recording medium P, the front and back of the recording medium P are reversed by the reversing unit 29, and the head unit 24 is reversed on the other surface of the recording medium P. The image is recorded (recording control means), and the reading operation start position is preset for each of the case where the surface of the recording medium P on which the image read by the reading operation is recorded is the front surface and the back surface.
Thus, even when the recording medium P when the reading of the image on the back surface is started is deformed as compared with when the reading of the image on the front surface is started, the recording medium P is adjusted to the contraction or expansion. The reading operation for reading the front and back images can be started at an appropriate start timing. For example, the distance from the leading end of the recording medium P to the image recording area Ra varies due to the deformation by starting reading from the reading start position S in accordance with the contraction or expansion of the leading end of the recording medium P. In addition, it is possible to start reading an image from a position at a predetermined interval Δ with respect to the image recording area Ra.

  Further, the inkjet recording apparatus 1 of the second embodiment includes a reversing unit that reverses the front and back of the recording medium P placed on the transport drum 211 and places the recording medium P on any of a plurality of placement positions. , An image is recorded on one surface of the recording medium P by the head unit 24, and then the front and back of the recording medium P are reversed by the reversing unit 29. The image is recorded by (recording control means), and the reading operation start position is the case where the surface of the recording medium P on which the image read by the reading operation is recorded at each of the plurality of mounting positions is the front surface and the back surface Is preset in advance. According to such a configuration, even when the recording medium P is placed at any of the plurality of placement positions, the image recorded on either the front surface or the back surface of the recording medium P at each placement position is read. Even when the operation is performed, the reading operation can be started at an appropriate start timing based on the reading operation start position set separately for each case.

The present invention is not limited to the above-described embodiments, and various modifications can be made.
For example, in each of the above-described embodiments, the conveyance drum 211 on which the recording medium P can be placed at three predetermined placement positions has been described as an example, but the number of placement positions is not limited to three. Two, or four or more may be used.

  In the image reading process of each of the above embodiments, the case where the image reading unit 27 reads a test image has been described as an example. However, the present invention is not limited to this, and the image to be read is an image other than the test image. Also good.

  In each of the above embodiments, the description has been given using the example in which the image reading unit 27 starts the reading operation at the timing when the position of the transport drum 211 coincides with the preset reading operation start position. However, the present invention is not limited to this. The reading operation may be started at a start timing corresponding to the timing at which the transport drum 211 moves to the reading operation start position. For example, a mode in which the reading operation by the image reading unit 27 is started at a start timing after a predetermined time lag after the transport drum 211 moves to the reading operation start position may be employed. In this case, it suffices to set the position closer to the reading operation start position by the rotation amount corresponding to the time lag from the optimum position of the transport drum 211 when the reading operation is started.

  In each of the above embodiments, the reading area Rb is set inside the recording medium P (inside the rectangle formed by the outer shape of the recording medium P). It may be set in a range from the inside to the outside. For example, the reading operation start position of the conveyance drum 211 may be set so that the reading start position S in FIG. 4 is on the downstream side in the conveyance direction with respect to the leading end of the recording medium P. Accordingly, the length of the reading region Rb in the transport direction may be set to be larger than the length of the recording medium P. Further, the width in the width direction of the reading region Rb may be set larger than the width of the recording medium P.

  In the second embodiment, the example in which the reading operation start positions related to the reading operation on the front surface and the back surface of the recording medium P are separately set has been described. However, the present invention is not limited to this. In the case where it is not necessary to consider the expansion, the reading operation start timing may be determined based on the same reading operation start position for each of the front and back surfaces of the recording medium P.

  In each of the above embodiments, the count value of the number of pulse signals output from the rotary encoder 52 is described as an example of the position correspondence information corresponding to the position of the transport drum 211. However, the present invention is not limited to this. The start timing of the reading operation may be controlled using other position correspondence information indicating the amount of movement of the transport member from the predetermined reference position.

  Further, in each of the above-described embodiments, the description has been given using the example in which the leading end of the recording medium P is detected by the detection unit 26 provided in the inkjet recording apparatus 1 in the reading operation start position setting operation. You may detect the front-end | tip of the recording medium P with the separate detection apparatus provided in the exterior of the apparatus 1. FIG.

  In each of the above embodiments, the reading operation start position is set based on the detection position of the leading end of the transport drum 211 when the detection unit 26 detects the leading end of the recording medium P. The method for setting the start position is not limited to this. For example, the image reading unit 27 starts the reading operation at the timing when the transport drum 211 moves to the temporary reading operation start position, reads an image on the recording medium P, and an imaging range of the obtained imaging data and a desired imaging range The reading operation start position may be set by correcting the provisional reading operation start position based on the difference between the reading operation start position and the reading operation start position. Specifically, the provisional reading operation start position is set so that reading starts from a position at a predetermined distance in the transport direction with respect to the front end of the recording medium P (for example, a position 1 cm downstream from the front end in the transport direction). When the distance between the leading end of the imaging range and the leading end of the recording medium P in the obtained imaging data is deviated from the predetermined distance, the temporary reading is performed according to the amount of misalignment. The reading operation start position may be set by correcting the reading operation start position. In this case, the detection unit 26 may not be provided in the inkjet recording apparatus 1.

Further, in each of the above embodiments, the example in which the claw portion 212 of the transport drum 211 defines the position of the leading end (downstream in the transport direction) of the recording medium P has been described. However, the present invention is not limited to this. The portion 212 may define the position of the rear end (upstream in the transport direction) of the recording medium P, or may define the positions of both the front end and the rear end.
Further, in each of the above embodiments, the claw portion 212 includes the position defining portion 212 a that defines the placement position of the recording medium P, and the clamping portion 212 b that clamps the end portion of the recording medium P between the conveyance drum 211. Although described using an example having both, the position defining portion and the sandwiching portion may be provided as separate components.

  In addition, the position of the transport drum 211 (fixing operation start position) when starting the fixing operation by the fixing unit 25 with respect to the recording medium P placed at each placement position is set in advance for each placement position. The fixing operation by the fixing unit 25 may be started at the timing when the conveyance drum 211 moves to the set fixing operation start position.

  In each of the above embodiments, the example in which the recording medium P is transported by the transport drum 211 has been described. However, the present invention is not limited to this. For example, the present invention may be applied to an ink jet recording apparatus that transports the recording medium P by a transport belt that is supported by two rollers and moves according to the rotation of the rollers.

  In each of the above-described embodiments, the inkjet recording apparatus 1 that forms an image with the line head in which the nozzle group is arranged over the image forming range in the width direction on the recording medium P has been described as an example. The present invention may be applied to an ink jet recording apparatus that records an image while scanning.

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

DESCRIPTION OF SYMBOLS 1 Inkjet recording apparatus 2 External apparatus 10 Paper feed part 11 Paper feed tray 12 Medium supply part 20 Image recording part 21 Conveyance part 211 Conveyance drum 211a Conveyance surface 212 Claw part 212a Position regulation part 212b Nipping part 213 Intake part 22 Delivery unit 23 Heating Unit 24 head unit 241 recording head drive unit 242 recording head 25 fixing unit 26 detection unit 27 image reading unit 28 delivery unit 29 reversing unit 30 paper discharge unit 31 paper discharge tray 40 control unit 41 CPU
42 RAM
43 ROM
44 Storage Unit 44a Reading Operation Start Position Data 51 Transport Drive Unit 52 Rotary Encoder 53 Operation Display Unit 54 Input / Output Interface 55 Bus 60 Test Image P Recording Medium Ra Image Recording Area Rb Reading Area

Claims (16)

A conveying means for performing a conveying operation of placing the recording medium at a predetermined placement position on the conveying member that moves around and conveying the recording medium;
Recording means for recording an image by ejecting ink to a recording medium that moves by the conveying operation;
Reading means for performing a reading operation of reading an image recorded on the recording medium by the recording means;
Position correspondence information acquisition means for acquiring position correspondence information corresponding to a position corresponding to the circular movement of the transport member;
Reading control means for controlling the start timing of the reading operation by the reading means based on the position correspondence information acquired by the position correspondence information acquisition means;
An ink jet recording apparatus comprising:   The inkjet recording apparatus according to claim 1, wherein the start timing is determined as a timing at which the position of the conveying member coincides with a reading operation start position set in advance according to the placement position.   The reading operation start position is the conveying member when the leading end of the recording medium placed at the setting position and the position where reading by the reading unit is performed have a predetermined positional relationship in the direction of the circular movement The ink jet recording apparatus according to claim 2, wherein Comprising storage means for storing reading operation start position information indicating the reading operation start position;
The ink jet recording apparatus according to claim 2, wherein the start timing is determined as a timing at which the position of the conveying member coincides with the reading operation start position indicated by the reading operation start position information. Detecting means for detecting the leading edge of the recording medium placed and conveyed at the placement position;
The reading operation start position information is set based on the position correspondence information acquired by the position correspondence information acquisition unit when the leading end of the recording medium is detected by the detection unit, and the reading operation start position information is stored in the memory. Reading operation start position setting means stored in the means;
The inkjet recording apparatus according to claim 4, comprising:   The inkjet recording apparatus according to claim 2, wherein a plurality of the installation positions are set on the conveying member. Reversing means for reversing the front and back of the recording medium placed on the conveying member and placing the recording medium at the placement position;
After the image is recorded on one surface of the recording medium by the recording means, the front and back of the recording medium are reversed by the reversing means, and the image is recorded by the recording means on the other surface of the recording medium. Recording control means;
With
The reading operation start position is preset for each of a case where the surface of the recording medium on which an image read by the reading operation is recorded is the one surface and the other surface. Item 6. The inkjet recording apparatus according to any one of Items 2 to 5. Reversing means for reversing the front and back of the recording medium placed on the conveying member and placing it on any of the plurality of placement positions;
After the image is recorded on one surface of the recording medium by the recording means, the front and back of the recording medium are reversed by the reversing means, and the image is recorded by the recording means on the other surface of the recording medium. Recording control means;
With
The reading operation start position is preset in each case where the surface of the recording medium on which the image read by the reading operation is recorded at each of the plurality of mounting positions is the one surface and the other surface. The inkjet recording apparatus according to claim 6, wherein the inkjet recording apparatus is set.   9. The position correspondence information acquisition unit acquires the position correspondence information indicating a movement amount of the transport member from a predetermined reference position in the transport operation. Inkjet recording apparatus.   The position correspondence information acquisition unit includes a movement detection unit that outputs a predetermined detection signal for each movement of the transport member by a predetermined amount, and acquires the position correspondence information from the output detection signal. The ink jet recording apparatus according to claim 9.   The inkjet recording apparatus according to claim 1, wherein the position correspondence information acquisition unit includes a rotary encoder. The transport means has a position defining portion that prescribes the mounting position on the transport member,
12. The recording medium according to claim 1, wherein at least one of a front end and a rear end of the recording medium is transported by being placed at the specified mounting position by the position specifying unit. An ink jet recording apparatus according to claim 1.   13. The conveyance unit according to claim 12, further comprising: a clamping unit that clamps an end portion of the recording medium, at least one of a leading end and a trailing end being stopped by the position defining unit, with the conveyance member. The ink jet recording apparatus described.   The conveying means includes a cylindrical drum, the recording medium is placed on an outer peripheral curved surface of the drum, and the conveying operation is performed by rotating the drum around a cylindrical axis. The ink jet recording apparatus according to claim 1. A transport unit that performs a transport operation for transporting the recording medium by placing the recording medium on a predetermined mounting position on a transport member that circulates; and ejects ink to the recording medium that is moved by the transport operation. Recording means for recording an image; reading means for performing a reading operation for reading an image recorded on the recording medium by the recording means; and position correspondence information corresponding to a position corresponding to the circular movement of the conveying member An image reading method of an ink jet recording apparatus comprising:
An image reading method for an ink jet recording apparatus, comprising: a reading control step of controlling a start timing of the reading operation by the reading unit based on the position correspondence information acquired by the position correspondence information acquisition unit. The start timing is determined as a timing at which the position of the transport member coincides with a reading operation start position set in advance according to the above-described placement position,
The image reading method is:
A detection step of detecting a tip of the recording medium that is placed and transported at the placement position;
A reading operation start position setting step for setting the reading operation start position based on the position correspondence information acquired by the position correspondence information acquisition means when the leading edge of the recording medium is detected in the detection step;
Including
The image reading method of the ink jet recording apparatus according to claim 15, wherein the detection step and the reading operation start position setting step are performed before the reading control step.