JP2019001046A - Transport device, liquid discharge device, and posture detection method - Google Patents

Abstract

To detect a posture of a transported object in a processing position.SOLUTION: The above object is achieved by a transport device including: a transport part which transports a transported object; a head unit which performs processing to the transported object; a first support member which is provided at the upstream of a processing position where the head unit performs the processing in a transport path and supports the transported object; a second support member which is provided at the downstream of the processing position and supports the transported object; a first detection part which is installed between the first support member and the second support member and detects a first detection result that is information of a transported object surface; a second detection part which is installed between the first support member and the second support member and at the downstream of the first detection part and detects a second detection result that is information of the transported object surface; and a posture detection part which detects a posture of the transported object on the basis of the first detection result and the second detection result.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transport device, a liquid ejection device, and a posture detection method.

  Conventionally, methods for performing various processes using a head unit are known. For example, a method of forming an image by a so-called ink jet method in which ink is ejected from a print head is known. As described above, in a device that performs processing on a transported object, if a shift occurs in the processing timing at which the process is performed or the position where the transported object is transported, a shift also occurs in the processing result.

  In order to improve the image quality of the image formed by the head unit, a method for detecting the shift amount of the recording medium is known. Specifically, a method is known in which a positional variation in the lateral direction of a web that is a recording medium used by the continuous paper printing system is detected by a sensor (see, for example, Patent Document 1).

  However, the conventional method has a problem that the posture of the conveyed object may not be detected at a position where the head unit performs processing (hereinafter referred to as “processing position”).

  An object of one aspect of the present invention is to detect the posture of a conveyed object at a processing position.

In order to solve the above-described problem, a transport apparatus according to one embodiment of the present invention includes:
A transport unit for transporting the object to be transported;
A head unit for processing the conveyed object;
A first support member that is provided upstream of a processing position at which the head unit performs the processing in a transport path, and supports the object to be transported;
A second support member provided downstream of the processing position and supporting the object to be conveyed;
A first detection unit that is installed between the first support member and the second support member and detects a first detection result that is surface information of the conveyed object;
A second detection unit that is installed between the first support member and the second support member and downstream of the first detection unit, and detects a second detection result that is surface information of the conveyed object;
A posture detection unit configured to detect a posture of the conveyed object based on the first detection result and the second detection result.

  It is possible to detect the posture of the conveyed object at the processing position.

It is the schematic which shows an example of the conveying apparatus which concerns on one Embodiment of this invention. It is the schematic which shows the example of whole structure of the conveying apparatus which concerns on one Embodiment of this invention. It is a figure which shows an example of the external shape of the liquid discharge head unit which concerns on one Embodiment of this invention. It is a block diagram which shows the hardware structural example which implement | achieves the attitude | position detection apparatus which concerns on one Embodiment of this invention. It is an external view which shows an example of the sensor device which concerns on one Embodiment of this invention. It is a functional block diagram which shows an example of a function structure of the attitude | position detection apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows an example of the correlation calculation method which concerns on one Embodiment of this invention. It is a figure which shows an example of the search method of the peak position in the correlation calculation which concerns on one Embodiment of this invention. It is a figure which shows the example of a calculation result of the correlation calculation which concerns on one Embodiment of this invention. It is the schematic which shows the structural example for detecting the attitude | position of the to-be-conveyed object which concerns on one Embodiment of this invention. It is a figure which shows the example of the deviation | shift amount in the orthogonal direction which concerns on one Embodiment of this invention. It is a flowchart which shows the example of an attitude | position detection process by the conveying apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows an example of the hardware constitutions of the control part which concerns on one Embodiment of this invention. It is a block diagram which shows an example of the hardware constitutions of the data management apparatus which the control part which concerns on one Embodiment of this invention has. It is a block diagram which shows an example of the hardware constitutions of the image output apparatus which the control part which concerns on one Embodiment of this invention has. It is a functional block diagram which shows an example of a function structure of the conveying apparatus which concerns on one Embodiment of the 1st modification of this invention. It is a timing chart which shows the example of detection of the position etc. of the to-be-conveyed object by the conveying apparatus which concerns on one Embodiment of this invention. It is the schematic which shows the hardware structural example for implement | achieving the moving part which concerns on one Embodiment of this invention. It is a conceptual diagram which shows the example which controls rotation of the head unit by the conveying apparatus which concerns on one Embodiment of 2nd Embodiment of this invention. It is a figure which shows an example of the hardware constitutions in a 1st comparative example. It is a functional block diagram which shows an example of a function structure of the conveying apparatus which concerns on one Embodiment of 2nd Embodiment of this invention. It is the schematic which shows the example of whole structure of the conveying apparatus which concerns on one Embodiment of 3rd Embodiment of this invention. It is the schematic which shows the example of rotation control of the supporting member by the conveying apparatus which concerns on one Embodiment of 3rd Embodiment of this invention. It is a flowchart which shows the skew correction process example by the conveying apparatus which concerns on one Embodiment of 3rd Embodiment of this invention. It is a functional block diagram which shows an example of a function structure of the conveying apparatus which concerns on one Embodiment of 3rd Embodiment of this invention. It is the schematic which shows the modification of the whole structure of the conveying apparatus which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that, in the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

<First Embodiment>
<Example of overall configuration>
Hereinafter, an example will be described in which the transport device includes a liquid discharge device, and the head unit included in the liquid discharge device is a liquid discharge head unit that performs a process of discharging liquid onto an object to be transported.

  FIG. 1 is a schematic diagram illustrating an example of a transport device according to an embodiment of the present invention. For example, a liquid ejection apparatus that is an example of a transport apparatus is an image forming apparatus as illustrated. In such an image forming apparatus, the discharged liquid is a recording liquid such as aqueous or oil-based ink. Hereinafter, an example in which the liquid ejecting apparatus is the image forming apparatus 110 will be described.

  The conveyed object is, for example, a recording medium. In the illustrated example, the image forming apparatus 110 forms an image by ejecting liquid onto a web 120 that is an example of a recording medium conveyed by a roller 130 or the like. The web 120 is a so-called continuous paper printing medium or the like. That is, the web 120 is roll-shaped paper or the like that can be wound. Hereinafter, an example in which the conveyed object is the web 120 will be described.

  As described above, the image forming apparatus 110 is a so-called production printer. In the following description, an example will be described in which the roller 130 adjusts the tension of the web 120 and the web 120 is conveyed in the illustrated direction (hereinafter referred to as “conveying direction 10”). Further, in the figure, the direction orthogonal to the transport direction 10 is an example of the orthogonal direction 20. In this example, the image forming apparatus 110 is an ink jet printer that forms an image on the web 120 by ejecting four colors of black (K), cyan (C), magenta (M), and yellow (Y). is there.

  In the following description, as shown in the drawing, the rotation around the vertical axis with respect to the transport direction 10 is referred to as “yaw rotation (Yaw) RY”. Further, the rotation around the traveling axis with respect to the transport direction 10 is referred to as “roll rotation (Roll) RR”. Furthermore, the rotation around the traveling axis with respect to the orthogonal direction 20 is referred to as “pitch rotation (Pitch) RP”.

  FIG. 2 is a schematic diagram illustrating an example of the overall configuration of a transport apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram of an example in which an image forming apparatus is used as an example of a transport device. As shown in the figure, the image forming apparatus 110 includes four liquid discharge head units for discharging each of the four ink colors.

  Each liquid discharge head unit discharges each liquid of each color to the web 120 conveyed in the conveyance direction 10. The web 120 is transported by two pairs of nip rollers, a roller 230, and the like. The roller 230 is a roller that is driven by a driving motor and drives the web 120, and is an example of a conveyance unit. Hereinafter, of the two pairs of nip rollers, a nip roller installed upstream of each liquid discharge head unit is referred to as a “first nip roller NR1”. On the other hand, a nip roller installed downstream from the first nip roller NR1 and each liquid discharge head unit is referred to as a “second nip roller NR2”.

  Each nip roller rotates with the web 120 interposed therebetween, as shown. Thus, each nip roller and roller 230 are a mechanism or the like that transports the web 120 in a predetermined direction.

  The web 120 is preferably long. Specifically, the length of the web 120 is preferably longer than the distance between the first nip roller NR1 and the second nip roller NR2. Further, the conveyed object is not limited to the web 120. In other words, the transported object may be paper that is folded and stored, so-called “Z paper” or the like.

  Hereinafter, in the illustrated overall configuration example, each liquid discharge head unit is installed in the order of black (K), cyan (C), magenta (M), and yellow (Y) from upstream to downstream. Specifically, the liquid discharge head unit (hereinafter referred to as “black liquid discharge head unit 210K”) installed at the most upstream is used for black (K).

  A liquid discharge head unit (hereinafter referred to as “cyan liquid discharge head unit 210C”) installed next to the black liquid discharge head unit 210K is used for cyan (C). Further, a liquid discharge head unit (hereinafter referred to as “magenta liquid discharge head unit 210M”) installed next to the cyan liquid discharge head unit 210C is used for magenta (M). Subsequently, the liquid discharge head unit (hereinafter referred to as “yellow liquid discharge head unit 210Y”) installed on the most downstream side is used for yellow (Y). The order of colors may be other than that shown in the figure.

  Each liquid ejection head unit performs a process of ejecting ink of each color onto a predetermined portion of the web 120 based on image data or the like. Further, the processing position (hereinafter referred to as “ejection position”) at which each liquid ejection head unit ejects ink is substantially equal to the position at which the liquid ejected from the liquid ejection head lands on the web 120, that is, the liquid For example, directly below the discharge head.

  In the illustrated example, the black ink is ejected to the ejection position of the black liquid ejection head unit 210K (hereinafter referred to as “black ejection position PK”). Similarly, cyan ink is ejected to the ejection position of the cyan liquid ejection head unit 210C (hereinafter referred to as “cyan ejection position PC”). Further, the magenta ink is ejected to the ejection position of the magenta liquid ejection head unit 210M (hereinafter referred to as “magenta ejection position PM”). The yellow ink is ejected to the ejection position of the yellow liquid ejection head unit 210Y (hereinafter referred to as “yellow ejection position PY”).

  The processing timing at which each liquid discharge head unit discharges ink is controlled by the controller 520 connected to each liquid discharge head unit.

  Hereinafter, an example in which the processing position by the liquid discharge head unit is the discharge position will be described.

  In the illustrated example, a plurality of rollers are installed for the liquid ejection head unit. As illustrated, the plurality of rollers are installed, for example, upstream and downstream with each liquid ejection head unit interposed therebetween.

  Specifically, a roller (hereinafter referred to as a “first roller”) that supports the web 120 is installed on the upstream side of each ejection position in the transport path of the web 120 for each liquid ejection head unit. In addition, a roller (hereinafter referred to as “second roller”) that supports the web 120 downstream from each discharge position is installed. Thus, when the first roller and the second roller are installed, so-called “flapping” can be reduced at each discharge position. The first roller and the second roller are, for example, driven rollers. The first roller and the second roller may be rollers that are rotated by a motor or the like.

  Note that the first roller that is an example of the first support member and the second roller that is an example of the second support member may not be a rotating body such as a driven roller. That is, the first support member and the second support member may be members that support the object. For example, the first support member and the second support member may be pipes or shafts having a circular cross section. In addition, the first support member and the second support member may be a curved plate or the like in which a portion in contact with the object has an arc shape. Hereinafter, an example in which the first support member is the first roller and the second support member is the second roller will be described.

  Specifically, the first black roller CR1K is installed on the upstream side in the conveyance direction of the web 120 at the black discharge position PK. On the other hand, the second black roller CR2K is installed on the downstream side in the conveyance direction of the web 120 from the black discharge position PK.

  Similarly, a cyan first roller CR1C and a cyan second roller CR2C are installed for the cyan liquid discharge head unit 210C. Further, a first magenta roller CR1M and a second magenta roller CR2M are installed for the magenta liquid ejection head unit 210M. Further, a yellow first roller CR1Y and a yellow second roller CR2Y are installed for the yellow liquid discharge head unit 210Y.

  In FIG. 2, for example, two or more sensor devices for detecting the web position in the transport direction, the orthogonal direction, or both directions are installed for each liquid ejection head unit. The sensor device includes a sensor that uses air pressure or ultrasonic waves. Alternatively, the sensor device includes an optical sensor that uses light such as visible light, laser, or infrared light. The optical sensor may be, for example, a CCD (Charge Coupled Device) camera or a CMOS (Complementary Metal Oxide Semiconductor) camera. That is, the sensor device includes, for example, a sensor that can detect the surface information of the web 100. Then, the image forming apparatus can detect the surface information of the web 120 by the sensor, and can detect a relative position, a moving speed, a moving amount, or a combination thereof among a plurality of detection results.

  FIG. 3 is a diagram showing an example of the outer shape of the liquid discharge head unit according to the embodiment of the present invention. FIG. 3A is a schematic plan view showing an example of each liquid discharge head unit.

  As illustrated, the liquid ejection head unit is, for example, a line type head unit.

  For example, the black liquid discharge head unit 210K has four heads 210K-1, 210K-2, 210K-3, and 210K-4 arranged in a staggered pattern in the orthogonal direction 20. For example, the head 210K-1 has a shape as shown in FIG. As a result, the black liquid discharge head unit 210K forms an image with black ink in the width direction (that is, the orthogonal direction 20) of an area where an image is formed on the web 120 (so-called printing area). can do. The other liquid discharge head units 210C, 210M, and 210Y have the same configuration as the black liquid discharge head unit 210K, for example, and will not be described.

  In the above description, the example in which the liquid discharge head unit is configured by four heads has been described. However, the liquid discharge head unit may be configured by a single head.

<Example of posture detection device>
FIG. 4 is a block diagram illustrating a hardware configuration example that realizes the attitude detection device according to the embodiment of the present invention. For example, the posture detection device is realized by hardware such as the sensor device SEN, the control circuit 52, the storage device 53, and the controller 520 as illustrated.

  First, the sensor device SEN is, for example, the following apparatus.

  FIG. 5 is an external view showing an example of a sensor device according to an embodiment of the present invention. The illustrated sensor device SEN is configured to image a pattern or the like formed on a transported object when light is emitted from the light source to the transported object. A pattern is an example of surface information of a conveyed object. Specifically, the sensor device SEN first includes a laser light source LD as a light source. Moreover, it has optical systems, such as a collimating optical system (CL). Further, the sensor device SEN includes an optical sensor OS as a sensor in order to capture a pattern. The optical sensor OS in FIG. 5 is a CMOS image sensor. The sensor device SEN has a telecentric imaging optical system (TO) for focusing and forming an image on a CMOS image sensor.

  For example, the optical sensor OS images a pattern or the like formed on the conveyed object. Then, the controller 520 performs processing such as correlation calculation based on the captured pattern and the pattern captured by the optical sensor OS included in the other sensor device SEN. Next, based on the movement of the correlation peak position calculated by correlation calculation or the like, the controller 520 calculates a relative position or the like between one optical sensor OS and the other optical sensor. In the illustrated example, the size of the sensor device SEN is an example in which width W × depth D × height H is 15 × 60 × 32 [mm]. Details of the correlation calculation will be described later.

  The CMOS image sensor is an example of hardware that realizes an imaging unit. In this example, the hardware for performing the correlation calculation is described as the controller 520. However, the correlation calculation may be executed by an FPGA circuit mounted on any sensor device.

  The control circuit 52 controls an optical sensor and the like inside the sensor device SEN. Specifically, for example, the control circuit 52 outputs a trigger signal to the optical sensor OS to control the timing at which the optical sensor OS releases the shutter. Further, the control circuit 52 performs control so that two-dimensional image data can be acquired from the sensor device SEN. Then, the control circuit 52 sends the two-dimensional image data generated by imaging by the sensor device SEN to the storage device 53 or the like.

  The storage device 53 is a so-called memory or the like. The storage device 53 preferably has a configuration capable of dividing the two-dimensional image data sent from the control circuit 52 and storing it in different storage areas.

  The controller 520 is a microcomputer or the like. The controller 520 performs calculations using image data and the like stored in the storage device 53.

  The storage device 55 is a device that stores calculation results of the controller 520 and the like.

  The control circuit 52 and the controller 520 are, for example, a CPU (Central Processing Unit) or an electronic circuit. Note that the control circuit 52, the storage device 53, the storage device 55, and the controller 520 need not be different devices. For example, the control circuit 52 and the controller 520 may be one CPU or the like. Further, the storage device 53 and the storage device 55 may be the same memory.

  FIG. 6 is a functional block diagram illustrating an example of a functional configuration of the posture detection apparatus according to an embodiment of the present invention. Hereinafter, as illustrated, a combination of a sensor device SENK1 and a sensor device SENK2 arranged in the black liquid discharge head unit 210K among two or more sensor devices installed for each liquid discharge head unit will be described as an example.

  The detection unit 52A includes, for example, an imaging unit 16A, an imaging control unit 14A, an image storage unit 15A, and the like. In this example, the detection unit 52B has the same configuration as the detection unit 52A, for example, and includes an imaging unit 16B, an imaging control unit 14B, an image storage unit 15B, and the like. For example, the detection unit 52A corresponds to the sensor device SENK1 and the like, and the detection unit 52B corresponds to the sensor device SENK2 and the like. Hereinafter, the detection unit 52A will be described as an example.

  The imaging unit 16A images the web 120 conveyed in the conveyance direction 10 as illustrated. Note that the imaging unit 16A is realized by, for example, the optical sensor OS (FIG. 4).

  The imaging control unit 14A includes a shutter control unit 141A and an image capturing unit 142A. The imaging control unit 14A is realized by, for example, the control circuit 52 or the like (FIG. 4).

  The image capturing unit 142A acquires image data captured by the imaging unit 16A.

  The shutter control unit 141A controls the timing at which the imaging unit 16A captures an image.

  The image storage unit 15A stores the image data captured by the imaging control unit 14A. The image storage unit 15A is realized by, for example, the storage device 53 or the like (FIG. 4).

  The calculation unit 53F can calculate the position of the pattern of the web 120, the moving speed of the web 120, and the amount of movement of the web 120 based on the image data stored in the image storage units 15A and 15B.

  Further, the calculation unit 53F outputs data of the time difference Δt indicating the timing of releasing the shutter to the shutter control unit 141A. That is, the calculation unit 53F indicates to the shutter control unit 141A the timing to release the shutter so that the image data indicating the “A position” and the image data indicating the “B position” are captured with a time difference Δt. Note that the calculation unit 53F is realized by, for example, the controller 520 (FIG. 2) or the like.

  The web 120 is a member having scattering properties on the surface or inside thereof. Therefore, when the web 120 is irradiated with laser light, the reflected light is diffusely reflected. A pattern is formed on the web 120 by the diffuse reflection. That is, the pattern is a spot called “speckle”, a so-called speckle pattern or the like. The pattern is an example of surface information on the web 120. Therefore, when the web 120 is imaged, image data indicating a pattern is obtained. Since the position of the pattern is known from the image data, the image forming apparatus 110 can detect where the predetermined position of the web 120 is. The pattern is generated because the irradiated laser beam interferes with the uneven shape formed on the surface or inside of the web 120.

  Therefore, when the web 120 is conveyed, the pattern of the web 120 is also conveyed. Therefore, when the same pattern is detected at different times, the image forming apparatus can calculate the movement amount of the web 120 based on the detection result. That is, when the same pattern as the pattern detected on the upstream side is detected on the downstream side, the image forming apparatus 110 can calculate the relative position or the movement amount of the web 120. The transport device can calculate the movement amount by calculating the movement amount per unit time.

  As illustrated, the imaging unit 16A and the imaging unit 16B are installed at regular intervals in the transport direction 10. And the web 120 is imaged in each position via the imaging part 16A and the imaging part 16B.

Then, the shutter control unit 141A causes the imaging unit 16A and the imaging unit 16B to image the web 120 at intervals of the time difference Δt. Based on the pattern indicated by the image data generated in this way, the calculation unit 53F calculates the movement amount of the web 120 and the like. Specifically, when the ideal transport speed is “V” and the relative distance, which is the distance between the imaging unit 16A and the imaging unit 16B installed in the transport direction 10, is “L”, the time difference Δt is expressed by the following (1). It can be shown as an expression.

Δt = L / V (1)

In the above equation (1), the relative distance L is the interval between the sensor device SENK1 and the sensor device SENK2, and therefore can be specified by measuring the interval between the sensor device SENK1 and the sensor device SENK2 in advance.

  Further, the image forming apparatus performs a cross-correlation operation on the image data “D1 (n)” and “D2 (n)” indicating the images captured by the detection unit 52A and the detection unit 52B. Hereinafter, the image data generated by the cross-correlation calculation is referred to as “correlation image”. For example, the image forming apparatus calculates at least one of the relative position in the orthogonal direction and the relative position in the transport direction between the two image data based on the correlation image.

For example, the cross-correlation calculation is a calculation represented by the following equation (2).

D1 * D2 * = F-1 [F [D1] · F [D2] *] (2)

In the above equation (2), image data “D1 (n)”, that is, image data indicating an image captured at “position A” is “D1”. Similarly, in the above equation (2), image data “D2 (n)”, that is, image data indicating an image picked up at “B position” is “D2”. Furthermore, in the above equation (2), the Fourier transform is indicated by “F []”, and the inverse Fourier transform is indicated by “F-1 []”. Furthermore, in the above equation (2), the complex conjugate is indicated by “*” and the cross-correlation operation is indicated by “★”.

  As shown in the above equation (2), when the cross-correlation calculation “D1 * D2” is performed on the image data D1 and D2, image data indicating a correlation image is obtained. If the image data D1 and D2 are two-dimensional image data, the image data indicating the correlation image is two-dimensional image data. When the image data D1 and D2 are one-dimensional image data, the image data indicating the correlation image is one-dimensional image data.

In the correlation image, for example, when a broad luminance distribution becomes a problem, the phase only correlation method may be used. The phase only correlation method is, for example, a calculation represented by the following equation (3).

D1 * D2 * = F-1 [P [F [D1]] · P [F [D2] *]] (3)

In the above equation (3), “P []” indicates that only the phase is extracted from the complex amplitude. The amplitudes are all “1”.

  In this way, the image forming apparatus can calculate the shift amount ΔD (n) based on the correlation image even with a broad luminance distribution.

  The correlation image indicates the correlation between the image data D1 and D2. Specifically, as the degree of coincidence between the image data D1 and D2 increases, a sharp peak, that is, a so-called correlation peak luminance is output at a position closer to the center of the correlation image. When the image data D1 and D2 match, the center and peak position of the correlation image overlap.

  Based on the result of the correlation calculation, information such as a position difference, a movement amount, or a movement speed between the image data D1 imaged with the time difference Δt and the image data D2 is output. For example, the calculation unit 53F can calculate how much the web 120 has moved in the orthogonal direction between the image data D1 and the image data D2 in the orthogonal direction. Note that the calculation unit 53F may calculate the movement speed instead of the movement amount.

  Furthermore, the calculation unit 53F can determine how much the web movement amount is deviated from the relative distance L in the transport direction based on the result of the correlation calculation. That is, from the two-dimensional image data captured by the imaging units 16A and 16B, the calculation unit 53F may also be used to detect the respective positions in the transport direction and the orthogonal direction.

  The deviation amount storage unit 55F stores the deviation amount in the orthogonal direction calculated by the calculation unit 53F. The deviation amount storage unit 55F is realized by the storage device 55 or the like.

  The posture detection unit 56F is a function that detects the posture of the web 120 based on the deviation amount stored in the deviation amount storage unit 55F. For example, the posture detection unit 56F is realized by the controller 520 or the like.

  The correlation calculation may be calculated as follows, for example.

  FIG. 7 is a block diagram showing an example of a correlation calculation method according to an embodiment of the present invention. For example, the image forming apparatus 110 can output a detection result indicating the relative position of the web, the moving amount, the moving speed, or a combination thereof when performing the correlation calculation with the configuration as illustrated. .

  Specifically, as illustrated, the image forming apparatus 110 includes a first two-dimensional Fourier transform unit FT1, a second two-dimensional Fourier transform unit FT2, a correlation image data generation unit DMK, a peak position search unit SR, an arithmetic operation. This is a configuration having a part CAL and a conversion result storage part MEM.

  The first two-dimensional Fourier transform unit FT1 transforms the first image data D1. Specifically, the first two-dimensional Fourier transform unit FT1 includes a Fourier transform unit FT1a for the orthogonal direction and a Fourier transform unit FT1b for the transport direction.

  The orthogonal direction Fourier transform unit FT1a performs one-dimensional Fourier transform on the first image data D1 in the orthogonal direction. Then, the Fourier transform unit FT1b for the transport direction performs one-dimensional Fourier transform on the first image data D1 in the transport direction based on the conversion result by the Fourier transform unit FT1a for the orthogonal direction. In this way, the Fourier transform unit FT1a for the orthogonal direction and the Fourier transform unit FT1b for the transport direction perform one-dimensional Fourier transform in the orthogonal direction and the transport direction, respectively. The first two-dimensional Fourier transform unit FT1 outputs the conversion result thus converted to the correlation image data generation unit DMK.

  Similarly, the second two-dimensional Fourier transform unit FT2 transforms the second image data D2. Specifically, the second two-dimensional Fourier transform unit FT2 includes a Fourier transform unit FT2a for orthogonal directions, a Fourier transform unit FT2b for transport directions, and a complex conjugate unit FT2c.

  The orthogonal direction Fourier transform unit FT2a performs one-dimensional Fourier transform on the second image data D2 in the orthogonal direction. Then, the Fourier transform unit FT2b for the transport direction performs one-dimensional Fourier transform on the second image data D2 in the transport direction based on the conversion result by the Fourier transform unit FT2a for the orthogonal direction. In this way, the Fourier transform unit FT2a for the orthogonal direction and the Fourier transform unit FT2b for the transport direction perform one-dimensional Fourier transform in the orthogonal direction and the transport direction, respectively.

  Next, the complex conjugate unit FT2c calculates the complex conjugate of the conversion result obtained by the Fourier transform unit FT2a for the orthogonal direction and the Fourier transform unit FT2b for the transport direction. Then, the second two-dimensional Fourier transform unit FT2 outputs the complex conjugate calculated by the complex conjugate unit FT2c to the correlation image data generation unit DMK.

  Subsequently, the correlation image data generation unit DMK outputs the conversion result of the first image data D1 output from the first two-dimensional Fourier transform unit FT1 and the second image output from the second two-dimensional Fourier transform unit FT2. Correlation image data is generated based on the conversion result of the data D2.

  The correlation image data generation unit DMK includes an integration unit DMKa and a two-dimensional inverse Fourier transform unit DMKb.

  The integrating unit DMKa integrates the conversion result of the first image data D1 and the conversion result of the second image data D2. Then, the integration unit DMKa outputs the integration result to the two-dimensional inverse Fourier transform unit DMKb.

  The two-dimensional inverse Fourier transform unit DMKb performs a two-dimensional inverse Fourier transform on the integration result obtained by the integration unit DMKa. In this way, when the two-dimensional inverse Fourier transform is performed, correlation image data is generated. Then, the two-dimensional inverse Fourier transform unit DMKb outputs the correlation image data to the peak position search unit SR.

  In the generated correlation image data, the peak position search unit SR searches for a peak position having a peak luminance (peak value) that is the steepest (that is, the rising edge is steep). First, the correlation image data is input with a value indicating the intensity of light, that is, the luminance. The luminance is input in a matrix.

  In the correlation image data, the luminance is arranged at the pixel pitch interval of the area sensor, that is, at the pixel size interval. Therefore, it is desirable that the search for the peak position is performed after performing so-called subpixel processing. Thus, when the subpixel processing is performed, the peak position can be searched with high accuracy. Therefore, the image forming apparatus 110 can output the position, the moving amount, the moving speed, and the like with high accuracy.

  For example, the search by the peak position search unit SR is performed as follows.

  FIG. 8 is a diagram illustrating an example of a peak position search method in correlation calculation according to an embodiment of the present invention. In the figure, the horizontal axis indicates the position in the conveyance direction in the correlation image data. On the other hand, the vertical axis indicates the luminance of the pixel indicated by the correlation image data.

  Hereinafter, three data of the first data value q1, the second data value q2, and the third data value q3 in the luminance indicated by the correlation image data will be described as an example. That is, in this example, the peak position search unit SR searches for the peak position P in the curve k connecting the first data value q1, the second data value q2, and the third data value q3.

  First, the peak position search unit SR calculates each luminance difference for each pixel indicated by the correlation image data. And the peak position search part SR extracts the combination of the data value from which the difference value becomes the largest among the calculated differences. Next, the peak position search unit SR extracts a combination adjacent to a combination of data values having the largest difference value. In this way, the peak position search unit SR can extract three pieces of data as shown in the first data value q1, the second data value q2, and the third data value q3. When the curve k is calculated by connecting the three extracted data, the peak position search unit SR can search for the peak position P. In this way, the peak position search unit SR can search for the peak position P at a higher speed by reducing the amount of calculation such as subpixel processing. Note that the position of the combination of data values with the largest difference value is the steepest position. The subpixel processing may be processing other than the above processing.

  As described above, when the peak position search unit SR searches for a peak position, for example, the following calculation result is obtained.

  FIG. 9 is a diagram illustrating a calculation result example of the correlation calculation according to the embodiment of the present invention. The figure shows the correlation strength distribution of the cross-correlation function. In the figure, the X axis and the Y axis indicate pixel serial numbers. A peak position such as a “correlation peak” shown in the figure is searched by the peak position search unit SR.

  The calculation unit CAL calculates a relative position, a moving amount, a moving speed, or the like of the web. For example, the calculation unit CAL can calculate the relative position and the movement amount by calculating the difference between the center position of the correlation image data and the peak position searched by the peak position search unit SR.

  Further, the calculation unit CAL can calculate the movement speed by dividing the movement amount by time, for example.

  As described above, the image forming apparatus 110 can detect the relative position, the moving amount, the moving speed, and the like by the correlation calculation. Note that the detection method of the relative position, the movement amount, the movement speed, and the like is not limited to this. For example, the image forming apparatus 110 may detect a relative position, a movement amount, a movement speed, or the like as follows.

  First, the image forming apparatus 110 binarizes the luminances of the first image data and the second image data. That is, the image forming apparatus 110 sets “0” if the luminance is equal to or less than a preset threshold value, and “1” if the luminance is larger than the threshold value. The image forming apparatus 110 may detect the relative position by comparing the binarized first image data and second image data.

  In addition, although the figure demonstrated the example which has a fluctuation | variation in a Y direction, when there exists a fluctuation | variation in a X direction, a peak position generate | occur | produces in the position shifted | deviated also to the X direction.

  Further, the image forming apparatus 110 may detect the relative position, the movement amount, the movement speed, and the like by a detection method other than this. For example, the image forming apparatus 110 may detect the relative position from each pattern appearing in each image data by so-called pattern matching processing or the like.

  When the correlation calculation is performed as described above, the image forming apparatus 110 can grasp a deviation amount indicating how much the conveyed object has deviated from a predetermined position in the conveyance direction, the orthogonal direction, or both directions.

<Example of posture detection and configuration>
FIG. 10 is a schematic diagram illustrating a configuration example for detecting the posture of a conveyed object according to an embodiment of the present invention. Hereinafter, the configuration of the black liquid discharge head unit 210K will be described as an example. That is, FIG. 10 is a top perspective view of the first black roller CR1K, the sensor device SENK1, the sensor device SENK2, and the second black roller CR2K corresponding to the black liquid discharge head unit in FIG.

  For example, the sensor device SENK2 is set between the first black roller CR1K and the second black roller CR2K and downstream of the sensor device SENK1. The sensor device SENK2 performs detection at a timing at which at least a part of the same pattern as that detected by the sensor device SENK1 can be detected. Then, based on the detection result of the sensor device SENK1 and the detection result of the sensor device SENK2, the controller 520 can detect the shift amount of the web 120 in the orthogonal direction 20 between the two detection positions. That is, the drawing shows an example in which the sensor device SENK1 realizes the first detection unit and the sensor device SENK2 realizes the second detection unit. For example, the image forming apparatus 110 detects the shift amount a plurality of times and stores it in the storage device 55 of FIG.

  FIG. 11 is a diagram illustrating an example of the shift amount in the orthogonal direction according to the embodiment of the present invention. The figure is an example of the result of plotting the detected deviation amount by the configuration shown in FIG. For example, it is assumed that the image forming apparatus 110 performs the process of detecting the deviation amount 100 times consecutively 10 times and acquires the deviation amounts for 1000 times in total. Then, by plotting the deviation amount for 1000 times in time series, data as shown in the figure can be generated.

  As shown in the figure, the deviation amount is a component that is substantially constant with respect to time (hereinafter referred to as “skew component ER1”) and a component whose amount varies periodically with respect to time (hereinafter referred to as “meandering component ER2”). ")") In many cases.

  In the example shown in FIG. 10, the skew component ER <b> 1 is generated due to a so-called skew state 120 </ b> A in which the web 120 is transported obliquely with respect to the transport direction 10.

  On the other hand, the meandering component ER2 is generated due to a so-called meandering state 120B in which the position of the web 120 varies in the orthogonal direction 20 in the example shown in FIG.

  For example, the skew state 120A occurs when the second black roller CR2K is inclined with respect to the first black roller CR1K.

  Furthermore, the meandering state 120B occurs, for example, due to eccentricity of a roller 230 (FIG. 2) used for conveyance, misalignment, or cutting of the web 120 by a blade. In particular, when the width of the web 120 is narrow with respect to the orthogonal direction, the thermal expansion of the roller or the like may affect the variation in the position of the web 120 in the orthogonal direction 20.

  Therefore, the meandering state 120B often becomes a periodic phenomenon based on the rotation period of the roller 230 or the like. Therefore, the meandering component ER2 often has periodicity. Therefore, the image forming apparatus acquires a sufficient number of deviations as shown in FIG. 11 and stores it in the storage device 55 of FIG. Then, the controller 520 can calculate the skew component ER <b> 1 by calculating the average value of the stored deviation amounts and removing the meandering component ER <b> 2 from the deviation amount. The skew component ER1 calculated in this way is the skew amount. The image forming apparatus 110 can detect the posture such as whether or not the web 120 is in the skew state 120A by calculating the skew amount.

  FIG. 12 is a flowchart illustrating an example of posture detection processing by the transport device according to the embodiment of the present invention. For example, when processing as shown in the figure is performed, the transport apparatus can perform the posture detection method in the configuration shown in FIG.

  In step SP01, the transport device detects the surface information of the transported object upstream. Specifically, in the example illustrated in FIG. 10, the transport device captures the pattern of the transported object and outputs first image data in the optical sensor OS of the sensor device SENK1.

  In step SP02, the transport device detects the surface information of the transported object downstream. Specifically, in the example illustrated in FIG. 10, the transport device captures the pattern of the transported object and outputs the second image data in the optical sensor OS of the sensor device SENK2.

  In step SP03, the controller 520 performs a correlation operation based on the detection result detected by the sensor device SENK1 and the detection result detected by the sensor device SENK2. As a result, the controller 520 calculates the shift amount of the conveyed object that occurs between the position of the sensor device SENK1 and the position of the sensor device SENK2.

  As shown in the figure, when steps SP01 to SP03 are repeated, the transport apparatus can acquire a plurality of deviation amounts.

  In step SP04, the transport device detects the posture of the transported object. For example, when the conveying device calculates the skew component ER1 and the meandering component ER2 as shown in FIG. 11 by averaging a plurality of deviation amounts, the object to be conveyed is in the skew state 120A, the meandering state 120B, or both. Whether or not the posture is included can be detected.

  Note that the processing as shown in the figure may be performed while the transport device performs processing on the object to be transported by the head unit. That is, each process of the posture detection method as shown in the figure may be performed during image formation on the conveyed object.

<Configuration example of control unit>
The controller 520 (FIG. 2), which is an example of the control unit, has a configuration described below, for example.

  FIG. 13 is a block diagram illustrating an example of a hardware configuration of a control unit according to an embodiment of the present invention. For example, the controller 520 includes a host device 71 that is an information processing device and the like, and a main body side control device 72. In the example shown in the figure, the controller 520 controls to form an image on the object to be conveyed under the control of the main body side control device 72 based on the image data and control data input from the host device 71.

  The host device 71 is, for example, a PC (Personal Computer). The main body side control device 72 includes a printer controller 72C and a printer engine 72E.

  The printer controller 72C controls the operation of the printer engine 72E. First, the printer controller 72C transmits / receives control data to / from the host device 71 via the control line 70LC. Further, the printer controller 72C transmits / receives control data to / from the printer engine 72E via the control line 72LC. When the control data is received, the printing conditions and the like indicated by the control data are input to the printer controller 72C, and the printer controller 72C stores the printing conditions and the like using a register or the like. Next, the printer controller 72C controls the printer engine 72E based on the control data, and forms an image according to the print job data, that is, the control data.

  The printer controller 72C includes a CPU 72Cp, a print control device 72Cc, and a storage device 72Cm. The CPU 72Cp and the print control device 72Cc are connected by a bus 72Cb and communicate with each other. The bus 72Cb is connected to the control line 70LC via a communication I / F (interface) or the like.

  The CPU 72Cp controls the operation of the entire main body side control device 72 by a control program or the like. That is, the CPU 72Cp is an arithmetic device and a control device.

  Based on the control data transmitted from the host device 71, the print control device 72Cc transmits / receives data indicating a command or status to the printer engine 72E. Thereby, the print control device 72Cc controls the printer engine 72E.

  Data lines 70LD-C, 70LD-M, 70LD-Y and 70LD-K, that is, a plurality of data lines are connected to the printer engine 72E. Then, the printer engine 72E receives image data from the upper apparatus 71 via a plurality of data lines. Next, the printer engine 72E performs image formation for each color based on control by the printer controller 72C.

  The printer engine 72E includes data management devices 72EC, 72EM, 72EY, and 72EK, that is, a plurality of data management devices. The printer engine 72E includes an image output device 72Ei and a conveyance control device 72Ec.

  FIG. 14 is a block diagram illustrating an example of a hardware configuration of a data management apparatus included in a control unit according to an embodiment of the present invention. For example, the plurality of data management devices have the same configuration. Hereinafter, an example in which each data management device has the same configuration will be described, and the data management device 72EC will be described as an example. Therefore, the overlapping description is omitted.

  The data management device 72EC includes a logic circuit 72ECl and a storage device 72ECm. As shown in the figure, the logic circuit 72ECl is connected to the host device 71 via the data line 70LD-C. Further, the logic circuit 72ECl is connected to the print control device 72Cc via the control line 72LC. The logic circuit 72ECl is realized by an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or the like.

  The logic circuit 72ECl stores the image data input from the host device 71 in the storage device 72ECm based on the control signal input from the printer controller 72C.

  The logic circuit 72ECl reads cyan image data Ic from the storage device 72ECm based on a control signal input from the printer controller 72C. Next, the logic circuit 72ECl sends the read cyan image data Ic to the image output device 72Ei.

  Note that the storage device 72ECm desirably has a capacity capable of storing image data of about three pages. When image data of about three pages can be stored, the storage device 72ECm can store image data input from the host device 71, image data during image formation, and image data for next image formation.

  FIG. 15 is a block diagram illustrating an example of a hardware configuration of an image output apparatus included in a control unit according to an embodiment of the present invention. As shown in the figure, the image output device 72Ei includes an output control device 72Eic, a black liquid discharge head unit 210K, a cyan liquid discharge head unit 210C, a magenta liquid discharge head unit 210M, and a yellow liquid discharge head that are liquid discharge head units for each color. Unit 210Y.

  The output control device 72Eic outputs the image data of each color to the liquid ejection head unit of each color. In other words, the output control device 72Eic controls the liquid discharge head unit of each color based on the input image data.

  The output control device 72Eic controls a plurality of liquid ejection head units simultaneously or individually. That is, the output control device 72Eic performs control to change the timing at which each liquid ejection head unit ejects liquid in response to timing input. The output control device 72Eic may control any of the liquid ejection head units based on a control signal input from the printer controller 72C. Further, the output control device 72Eic may control any of the liquid ejection head units based on an operation by the user.

  The main body side control device 72 uses different paths for inputting image data from the higher order device 71 and different paths for transmission / reception between the higher order device 71 and the main body side control device 72 based on the control data. It is an example.

  As described above, the posture of the conveyed object can be detected by performing the processing as shown in FIGS.

<First Modification>
FIG. 16 is a functional block diagram illustrating an example of a functional configuration of a transport apparatus according to an embodiment of the first modified example of the present invention. Hereinafter, a functional configuration of the cyan liquid ejection head unit 210C will be described as an example. As illustrated, the image forming apparatus 110 has a functional configuration including, for example, a first detection unit 52A, a third detection unit 52C, a fourth detection unit 52D, an attitude detection unit 56F, and a calculation unit 53F. . The image forming apparatus 110 preferably has a functional configuration further including a moving unit 110F3 and a control unit 54F, as illustrated. Hereinafter, the functional configuration shown in the figure will be described as an example.

  First, the image forming apparatus 110 includes a cyan first roller CR1C upstream of the cyan discharge position PC. On the other hand, the image forming apparatus 110 includes a second cyan roller CR2C downstream of the cyan discharge position PC.

  For example, the first detection unit 52A detects the surface information of the web 120 using the inter-black roller INTK1 between the first black roller CR1K and the second black roller CR2K. The first detection unit is realized by the sensor device SENK1 illustrated in FIG. The description of the detection unit is the same as in FIG. The first detection unit 52A does not need to be the sensor device SENK1, and may be realized by the sensor device SEN disposed upstream of the sensor device SENC1 disposed between the cyan rollers.

  The third detection unit 52C detects the surface information of the web 120 at the inter-cyan roller INTC1 between the first cyan roller CR1CK and the second cyan roller CR1C2. The third detection unit 52C is a function realized by the sensor device SENC1 shown in FIG.

  The fourth detection unit 52D detects the surface information of the web 120 downstream of the third detection unit, which is the inter-cyan roller INTC1 between the first cyan roller CR1C and the second cyan roller CR2C. The fourth detection unit 52D is realized by the sensor device SENC2.

  The calculation unit 53F is realized by the controller 520 shown in FIG. The calculation unit 53F performs a correlation operation on the detection results of the third detection unit and the fourth detection unit, and calculates a deviation amount in the orthogonal direction. The functions of the deviation amount storage unit 55F and the posture detection unit 56F are the same as those in FIG.

  Further, the calculation unit 53F performs a correlation calculation on the detection results of the first detection unit 52A and the third detection unit 52C. As described with reference to FIG. 6, the calculation unit 53 </ b> F can calculate how much the web has moved in the orthogonal direction. The calculation unit 53F can calculate the amount of movement of the cyan liquid ejection head unit 210C in the orthogonal direction from the calculation result based on the detection results of the first detection unit 52A and the third detection unit 52C.

  Further, as described with reference to FIG. 6, the calculation unit 53 </ b> F can calculate how much the movement amount of the web in the conveyance direction has deviated from the ideal movement amount L <b> 2. That is, the calculation unit 53F can calculate the discharge timing of the cyan liquid discharge head unit 210C from the calculation result based on the detection results of the first detection unit 52A and the third detection unit 52C.

  Based on the calculation result of the calculation unit 53F, the moving unit 110F3 controls an actuator ACT described later to control the landing position of the cyan liquid. The moving unit 57F is configured by an actuator controller CTL described later, for example. The function of the moving unit 57F may be configured with the controller 520 as well as the actuator controller CTL. The controller 520 may also be used.

  The controller 54F controls the ejection timing of the cyan liquid ejection head unit 210C.

  FIG. 17 is a timing chart illustrating an example of detection of the position and the like of the object to be transported by the transport device according to the embodiment of the present invention.

  The image forming apparatus 110 calculates a variation amount of the position of the conveyed object based on the plurality of sensor data. Specifically, based on the first sensor data S1 and the second sensor data S2, the image forming apparatus outputs a calculation result indicating the variation amount. In the illustrated detection, sensor data indicating the first detection result, that is, the detection result output by the upstream detection unit is the first sensor data S1. On the other hand, the sensor data indicating the third detection result, that is, the detection result output by the detection unit downstream from the first detection result is the second sensor data S2.

  The fluctuation amount is calculated for each liquid discharge head unit, for example. Hereinafter, an example of calculating the fluctuation amount for the cyan liquid ejection head unit 210C will be described. In this example, the sensor device SENK1 outputs first sensor data S1 indicating the first detection result, while the sensor device SENC1 outputs second sensor data S2 indicating the second detection result.

  Hereinafter, it is assumed that the distance between the sensor device SENK1 and the sensor installed in the sensor device SENC1, that is, the distance between the sensors is “L2”. Further, it is assumed that the moving speed detected based on the sensor data is “V”. Furthermore, it is assumed that the movement time that elapses while the conveyed object is conveyed from the sensor device SENK1 to the sensor device SENC2 is “T2”. In this case, the travel time is calculated as “T2 = L2 / V”.

  The sampling interval by the sensor is “A”. Furthermore, the number of samplings between sensors is “n”. In this case, the sampling count is calculated as “n = T2 / A”.

  The calculation result shown in the drawing, that is, the fluctuation amount is “ΔX”. For example, as shown in the figure, when the detection cycle is “0”, the fluctuation amount is calculated by using the first sensor data S1 before the movement time “T2” and the second sensor data S2 of the detection cycle “0”. Calculated by comparison. Specifically, the fluctuation amount is calculated as “ΔX = X2 (0) −X1 (n)”.

  Next, the image forming apparatus 110 controls the actuator so as to compensate for the fluctuation amount “ΔX”, and moves the cyan liquid ejection head unit 210C in the orthogonal direction. In this way, even if the position of the transported object fluctuates, the image forming apparatus 110 can perform processing on the transported object with high accuracy. Further, if the fluctuation amount is calculated based on sensor data between two points with the most upstream sensor, the fluctuation amount can be calculated without integrating the position information of each sensor. Therefore, if this is done, the accumulation of detection errors by each sensor can be reduced.

  The sensor data is not limited to a detection result detected by a sensor installed one upstream from the liquid discharge head unit to be moved. In other words, the sensor may be a sensor installed on the upstream side of the liquid discharge head unit to be moved.

  The second sensor data S2 is preferably a detection result by a sensor installed at a position closest to the liquid discharge head unit to be moved.

  Further, the fluctuation amount or the like may be calculated based on three or more detection results.

  As described above, based on the fluctuation amount calculated from the plurality of sensor data, the image forming apparatus 110 performs control for moving the liquid ejection head unit and performs processing on the web 120.

  Among the sensor devices used for controlling the discharge timing of the liquid discharge head unit or controlling the position of the liquid discharge head unit in the orthogonal direction, the detection position of the sensor device that outputs the second sensor data S2 is set to each discharge It is desirable that the position is close to the position. If detection can be performed at a position close to each discharge position, the distance between the processing position and the sensor is shortened. When the distance between the processing position and the sensor is shortened, the detection error is reduced. Therefore, the image forming apparatus 110 can accurately detect the position, the moving amount, the moving speed, or a combination thereof in the transport direction, the orthogonal direction, or both directions.

  Of the sensor devices used for controlling the discharge timing or the position of the liquid discharge head unit in the orthogonal direction, the detection position of the sensor device that outputs the second sensor data S2 is set between the rollers. It is more desirable that the position is closer to the first roller than the position. That is, it is more desirable that the position where the sensor is installed is upstream from each discharge position.

  For example, the sensor device SENC1 is preferably between the cyan discharge position PC and the position where the first cyan roller CR1C is installed upstream (hereinafter referred to as “cyan upstream section INTC2”). The same applies to other liquid discharge head units.

  When the sensor is installed at such a position, the correlation calculation is performed based on the detection result of the sensor device upstream from each discharge position. Therefore, the image forming apparatus 110 first calculates the position of the object to be conveyed in the orthogonal direction, the conveyance direction, or both directions by a sensor upstream. Therefore, the image forming apparatus 110 can calculate the processing timing at which each liquid discharge head unit discharges liquid, the amount by which the head unit is moved, or both.

  That is, since the web 120 is transported to the discharge position after the position of the transported object is detected upstream, the image forming apparatus 110 calculates the processing timing or the web 120 while the web 120 is transported to the discharge position. The head unit can be moved. Therefore, the image forming apparatus 110 can change the processing position with high accuracy.

  On the other hand, if the position where the sensor device that outputs the second sensor data is installed is directly below each liquid discharge head unit, the position where the processing is performed may be shifted due to a delay in the control operation or the like. . Therefore, when the position where the sensor device that outputs the second sensor data is installed is upstream of each ejection position, the image forming apparatus 110 can reduce the deviation and perform processing with high accuracy. In addition, the vicinity of each discharge position may be restricted to a position where a sensor or the like is installed. Therefore, the position where the sensor is installed is preferably closer to the first roller than each discharge position.

  However, the position where the sensor device that outputs the second sensor data is installed may be directly below each liquid ejection head unit. When the sensor is directly underneath, there is an effect that an accurate movement amount immediately under the sensor can be detected by the sensor. For example, if the control operation or the like can be performed quickly, it may be desirable that the sensor is located closer to the position immediately below each liquid ejection head unit. In addition, if the error can be tolerated, the position of the sensor is directly below each liquid discharge head unit or between each first roller and each second roller, from directly below each liquid discharge head unit. It may be a downstream position or the like.

  FIG. 18 is a schematic diagram illustrating a hardware configuration example for realizing a moving unit according to an embodiment of the present invention. For example, the moving unit 110F3 is realized by hardware as illustrated. Hereinafter, a hardware configuration example for moving the cyan liquid discharge head unit 210 </ b> C will be described as shown in the drawing.

  First, in the illustrated example, an actuator ACT such as a linear actuator that moves the cyan liquid discharge head unit 210C is installed in the cyan liquid discharge head unit 210C. The actuator ACT is connected to an actuator controller CTL that controls the actuator ACT.

  The actuator ACT is, for example, a linear actuator or a motor. Further, the actuator ACT may include a control circuit, a power supply circuit, a mechanical component, and the like.

  The actuator controller CTL is, for example, a driver circuit. The actuator controller CTL controls the position of the cyan liquid ejection head unit 210C.

  The actuator controller CTL receives the fluctuation amount calculated as shown in FIG. Then, the actuator controller CTL moves the cyan liquid discharge head unit 210 </ b> C by the actuator ACT so as to compensate for the variation in the position of the web 120. Specifically, in the illustrated example, the variation amount based on the plurality of detection results is the variation “Δ”. Therefore, in this example, the actuator controller CTL moves the cyan liquid ejection head unit 210C in the orthogonal direction 20 so as to compensate for the variation Δ.

  Note that hardware for realizing the moving unit may be integrated with hardware such as the controller 520 or may be separate.

  As described above, when there is the moving unit 110F3, the image forming apparatus 110 calculates the amount of change in the position of the conveyed object in the orthogonal direction, that is, the amount of deviation calculated based on the first detection result and the third detection result. It is possible to compensate and accurately process the conveyed object. In particular, the image forming apparatus 110 can compensate for the shift amount during image formation by the moving unit 110F3.

  Further, by using the third detection unit also as a detection unit that detects a detection result used in the posture detection unit, it is possible to efficiently compensate for the shift amount.

Second Embodiment
In the second embodiment, in addition to the configuration of the first embodiment, a head unit rotation control unit that yaw-rotates the head unit is further provided. In the following, the description will focus on the differences from the first embodiment, and a duplicate description will be omitted.

  FIG. 19 is a conceptual diagram illustrating an example of controlling the rotation of the head unit by the transport device according to one embodiment of the second embodiment of the present invention. Hereinafter, the black liquid discharge head unit 210K will be described as an example. In the drawing, the black liquid discharge head unit 210K before rotation control is performed (assuming that there is no skew before rotation control is performed) is indicated as “head unit HU1 before control”. . On the other hand, in the drawing, the black liquid discharge head unit 210K after the rotation control is performed is indicated as “post-control head unit HU2”.

  The position where black ink is ejected by the pre-control head unit HU1 and the liquid lands on the transported object is referred to as “pre-control landing position PK1”. On the other hand, a position where black ink is ejected by the post-control head unit HU2 and the liquid lands on the transported object is referred to as a “post-control landing position PK2.”

  Further, the coordinates of the position indicated by the detection result in the sensor device SENK1 are (x1, y1), and the coordinates of the position indicated by the detection result in the sensor device SENK2 are (x2, y2). Further, the inter-sensor distance between the sensor device SENK1 and the sensor device SENK2 is referred to as “ΔLx”. The inter-sensor distance ΔLx can be specified by measuring the distance between the sensors in advance.

  In the following description, it is assumed that the web 120 is in the skew state 120A as illustrated. The black liquid discharge head unit 210K is controlled to rotate around the end portion P0 (hereinafter, simply referred to as “end portion P0”) of the web 120 in the skew state 120A.

  First, when processing as shown in FIG. 12 is performed, the position (P0x, P0y) of the end portion P0 can be calculated from the detection result of the posture. Specifically, “P0y” can be specified from the skew amount or the like.

Further, when the difference between “y2” and “y1” is “yd”, “yd” can be specified by calculation as shown in the following equation (4).

yd = y2-y1 (4)

Note that “yd” can also be specified by a calculation such as the following equation (5), where “θ” is an angle formed between the web edge in a state where there is no skew and the web edge in the skew state 120A.

yd = ΔLx × tan θ (5)

Further, “θ” can be specified by calculating the following equation (6), for example.

θ = tan ⁻¹ (yd / ΔLx) (6)

“P0y” can be expressed by the following equation (7).

P0y = yd × (P0x / ΔLx)
= (Y2−y1) × (P0x / ΔLx)
= (ΔLx × tan θ) × (P0x / ΔLx)
= P0x × tan θ (7)

In order to accurately process the web in the skewed state 120A, the image forming apparatus 110 causes the black liquid discharge head unit 210K to yaw RY as illustrated.

  Therefore, in the second embodiment, the image forming apparatus 110 includes an actuator having a degree of freedom to rotate each head unit by yaw rotation RY. Then, the image forming apparatus 110 rotates the pre-control head unit HU1 by yaw RY by “θ” calculated by the above formula to obtain the post-control head unit HU2.

  When the head unit is rotated in this manner, the image forming apparatus 110 can perform processing at the pre-control landing position PK2. As shown in the drawing, the pre-control landing position PK2 is substantially orthogonal to the web end in the skew state 120A. Therefore, as shown in the drawing, the image forming apparatus 110 can perform processing with high accuracy even if skewing occurs if rotation control is performed.

  Note that the rotation control as illustrated is preferably performed while the processing is not performed by the head unit, for example, before the processing is performed by the head unit or while the processing by the head unit is stopped. On the other hand, posture detection or the like may be performed while processing is performed by the head unit.

  In addition to the rotation control, control for moving the head unit in the orthogonal direction as shown in FIG. 18 may be performed.

<Comparative example>
FIG. 20 is a diagram illustrating an example of a hardware configuration in the first comparative example. The first comparative example shown in the figure detects the position of the web 120 before each liquid discharge head unit is transported to the discharge position. In this comparative example, the position where the sensor is installed is a position that is “200 mm” from directly under the liquid discharge head unit. Based on the detection result in this case, the image forming apparatus according to the first comparative example moves the liquid ejection head unit to compensate for the variation in the position of the web 120.

  In the first comparative example, the variation is compensated based on the detection result detected 200 mm upstream from the liquid ejection head unit, so that the detection error is large and color misregistration or the like is likely to occur. Further, in the configuration as in the first comparative example, since there is no degree of freedom in the yaw rotation RY, it is difficult to perform the rotation control as shown in FIG. 19 in the first comparative example.

<Functional configuration example>
FIG. 21 is a functional block diagram illustrating an example of a functional configuration of a transport apparatus according to an embodiment of the second embodiment of the present invention. Compared to the first embodiment, the second embodiment is different in that there is a head unit rotation control unit 110F4. In the following, the description will focus on the differences from the first embodiment, and a duplicate description will be omitted.

  The head unit rotation control unit 110F4 rotates the black liquid discharge head unit 210K about the vertical axis with respect to the transport direction 10 (that is, the yaw rotation RY) based on the skew amount detected by the posture detection unit 56F. Let For example, the head unit rotation control unit 110F4 is realized by an actuator having a degree of freedom of yaw rotation RY. The function of the posture detection unit 56F is the same as that described with reference to FIG.

  Based on the skew amount detected by the posture detection unit 56F, the image forming apparatus 110, for example, rotates the head unit yaw RY. In this way, the image forming apparatus 110 can accurately process the object to be conveyed even when skewing occurs.

<Third Embodiment>
FIG. 22 is a schematic diagram illustrating an example of the overall configuration of a transport apparatus according to an embodiment of the third embodiment of the present invention. The third embodiment is different from the first embodiment in that an actuator for tilting the second roller is added. In the following, the description will focus on the differences from the first embodiment, and a duplicate description will be omitted.

  For example, as shown in the figure, the black actuator RAK is installed on the second black roller CR2K. Similarly, the cyan actuator RAC is installed in the second cyan roller CR2C. Further, a magenta actuator RAM is installed on the second magenta roller CR2M. Furthermore, a yellow actuator RAY is installed on the second yellow roller CR2Y. Each actuator is controlled by the adjusting device 521 or the like.

  The adjustment device 521 is an information processing device. Further, the adjusting device 521 may be integrated with the controller 520 or the like. On the other hand, the adjustment device 521 may be a plurality of devices.

  Each actuator is controlled as follows by the adjusting device 521, for example.

  FIG. 23 is a schematic diagram illustrating an example of rotation control of the support member by the transport device according to an embodiment of the third embodiment of the present invention. Hereinafter, the black second roller CR2K will be described as an example.

  For example, the black actuator RAK has a degree of freedom to raise and lower one end of the second black roller CR2K in the vertical direction 30. As shown in the figure, when the black actuator RAK moves one end of the second black roller CR2K up and down, the second black roller CR2K rotates RR around the other end. Therefore, the image forming apparatus 110 can adjust the inclination of the second black roller CR2K by the black actuator RAK.

  When the inclination of the second black roller CR2K changes, the skew amount often changes. Therefore, the image forming apparatus 110 uses the adjustment device 521 to change the inclination of the second black roller CR2K so that the skew amount becomes a value smaller than the predetermined amount.

  The predetermined amount is a value set in advance. Further, the skew amount is detected by, for example, a detection method as shown in FIG.

  Note that the image forming apparatus 110 may perform control to move a portion other than one end of the roller. That is, the image forming apparatus 110 may move any part of the roller as long as the support member can be rotated RR.

  The image forming apparatus 110 is not limited to the second support member, and may perform control to rotate the first support member or both support members.

  For example, when the web 120 is replaced, the posture of the web 120 is likely to change. Therefore, it is desirable for the image forming apparatus 110 to perform the following overall processing when the web 120 is replaced.

  FIG. 24 is a flowchart illustrating an example of skew correction processing by the transport device according to an embodiment of the third embodiment of the present invention. In the following, the same processes as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. Compared with the first embodiment, the third embodiment is different in that the processing of step SP31 to step SP36 is added.

  In step SP31, the image forming apparatus 110 determines whether or not to perform adjustment. For example, when the web 120 is switched, the image forming apparatus 110 conveys the web 120 as the adjustment mode. Therefore, in this example, when the adjustment mode is set, the image forming apparatus 110 determines to perform adjustment (YES in step SP31), and proceeds to step SP32. On the other hand, if the adjustment mode is not set, the image forming apparatus 110 determines that no adjustment is performed (NO in step SP31), and ends the process.

  In step SP32, the image forming apparatus 110 starts a timer. That is, the image forming apparatus 110 starts measuring the time that has elapsed since entering the adjustment mode (hereinafter simply referred to as “elapsed time”).

  When step SP01 to step SP04 are performed, the posture of the web 120, the skew amount, and the like are detected by the processing shown in FIG.

  In step SP33, the image forming apparatus 110 determines whether the skew feeding amount is equal to or less than a predetermined amount. Next, when the skew feeding amount is equal to or less than the predetermined amount (YES in step SP33), the image forming apparatus 110 ends the process. In this case, since the skew amount is sufficiently small, adjustment is not necessary. On the other hand, if the skew amount is not less than the predetermined amount (NO in step SP33), the image forming apparatus 110 proceeds to step SP34.

  In step SP34, the image forming apparatus 110 determines whether the elapsed time is within a predetermined time. The predetermined time is a preset time. For example, the predetermined time is set to “5 minutes” or the like. The image forming apparatus 110 compares the elapsed time with the predetermined time. If the elapsed time is within the predetermined time (YES in step SP34), the image forming apparatus 110 proceeds to step SP35. On the other hand, if the image forming apparatus 110 determines that the elapsed time is not within the predetermined time (NO in step SP34), the process proceeds to step SP36.

  In step S35, the image forming apparatus 110 performs control to tilt the support member. That is, the image forming apparatus 110 performs control for tilting the support member as shown in FIG. 27, for example, based on the skew amount detected in step SP04. In this way, the image forming apparatus 110 performs control to tilt the support member so that the skew amount becomes a small value.

  In step S36, the image forming apparatus 110 performs error processing. For example, the image forming apparatus 110 notifies the user that an error has occurred by transmitting an error message to the user. Step S36 is a process performed when a so-called time-over occurs.

  When the above processing is performed, the skew amount becomes a small value. Therefore, the image forming apparatus 110 can perform processing such as image formation with less skew. Therefore, the image forming apparatus 110 can perform processing on the transported object with high accuracy.

<Functional configuration example>
FIG. 25 is a functional block diagram illustrating an example of a functional configuration of a transport apparatus according to an embodiment of the third embodiment of the present invention. Compared with the first embodiment, the third embodiment is different in that there is a support member rotation control unit 110F5. In the following, the description will focus on the differences from the first embodiment, and a duplicate description will be omitted.

The support member rotation control unit 110F5 rotates the black liquid ejection head unit 210K about the traveling axis with respect to the transport direction 10 (that is, the roll rotation RR) based on the skew amount detected by the posture detection unit 56F. Let For example, the support member rotation control unit 110F5 is realized by an actuator having a degree of freedom of roll rotation RR as shown in FIG. The function of the posture detection unit 56F is the same as that described with reference to FIG.
Based on the skew amount detected by the posture detection unit 56F, the image forming apparatus 110, for example, rotates the second support member or the like by roll rotation RR. In this way, the image forming apparatus 110 can process the conveyed object with high accuracy by setting the skew amount to a small value.

<Modification>
FIG. 26 is a schematic diagram illustrating a modification of the overall configuration of the transport apparatus according to an embodiment of the present invention. Compared to FIG. 2, the arrangement of the first support member and the second support member is different in the illustrated configuration. As illustrated, the first support member and the second support member may be realized by, for example, the first member RL1, the second member RL2, the third member RL3, the fourth member RL4, and the fifth member RL5. . That is, the second support member provided on the upstream side of each liquid discharge head unit and the first support member provided on the downstream side of each liquid discharge head unit may be combined. Note that the first support member and the second support member may be combined with a roller or a curved plate.

  The present invention is also applicable to an apparatus that performs some processing using line-shaped head units arranged in an orthogonal direction.

  For example, the embodiment according to the present invention may be a transport device that performs patterning processing on a substrate, which is a transported object, using a laser emitted from a head unit. Specifically, the transport device first has laser heads arranged in a line in the orthogonal direction. The transfer device detects the position of the substrate and moves the head unit based on the detection result. In this example, the processing position is the processing position at which the laser is irradiated on the substrate.

  In addition, in the embodiment according to the present invention, the head unit may perform a reading process of reading an image formed on the conveyed object. That is, when the head unit is a so-called scanner or the like, the head unit can read an image formed on the transported object and generate image data. In this example, the position where the head unit reads the image formed on the conveyed object is the processing position.

  Further, the transport device does not have to have a plurality of head units. That is, the present invention can be applied to a case where processing is continued at a reference position with respect to an object to be conveyed.

<Other embodiments>
The light source is not limited to one using laser light. For example, the light source may be an LED (Light Emitting Diode) or an organic EL (Electro-Luminescence). Depending on the light source, the pattern may not be a speckle pattern.

  The light source may be a light source having a single wavelength or a light source having a broad wavelength.

  In the above embodiment, the image forming apparatus that performs image formation using the liquid discharge head units of four colors of black, cyan, magenta, and yellow has been described as an example. However, the image forming apparatus may include a plurality of black liquid discharge head units, for example, and perform image formation.

  Further, the conveyed object is not limited to a recording medium such as paper. The material to be conveyed may be a material to which a liquid can adhere. For example, the material to which the liquid can be attached is not limited as long as the liquid such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, or a combination thereof can be attached temporarily.

  The embodiment may be realized by a transport system having one or more devices. For example, the black liquid discharge head unit 210K and the cyan liquid discharge head unit 210C are apparatuses in the same casing, and the magenta liquid discharge head unit 210M and the yellow liquid discharge head unit 210Y are apparatuses in the same casing, both of which are included. It may be realized by a transport system.

  Each process may be performed in parallel, redundantly, or distributedly by a plurality of information processing apparatuses included in the transport system.

  Further, in the transport device, the liquid discharge device including the transport device, and the transport system according to the present invention, the liquid is not limited to ink, but may be another type of recording liquid or fixing processing liquid. In other words, the transport device, the liquid discharge device including the transport device, and the transport system according to the present invention may be applied to a device that discharges a type of liquid other than ink.

  Accordingly, the transport device, the liquid discharge device including the transport device, and the transport system according to the present invention are not limited to performing the process of forming an image. For example, the formed object may be a three-dimensional structure.

  Further, in the embodiment according to the present invention, the present invention may be realized by a program for causing a computer such as a transport apparatus, a liquid ejection apparatus including the transport apparatus, and a transport system to execute the attitude detection method. Therefore, when the attitude detection method is executed based on the program, the calculation device and the control device included in the computer perform calculation and control based on the program in order to execute each process. In addition, a storage device included in the computer stores data used for processing based on a program in order to execute each processing.

  The program can be recorded and distributed on a computer-readable recording medium. The recording medium is a medium such as a magnetic tape, a flash memory, an optical disk, a magneto-optical disk, or a magnetic disk. Furthermore, the program can be distributed through a telecommunication line.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Or it can be changed.

110 Image forming apparatus 120 Web 210K Black liquid discharge head unit 210C Cyan liquid discharge head unit 210M Magenta liquid discharge head unit 210Y Yellow liquid discharge head unit 520 Controller

Japanese Patent Laying-Open No. 2015-13476

Claims (11)

A transport unit for transporting the object to be transported;
A head unit for processing the conveyed object;
A first support member that is provided upstream of a processing position at which the head unit performs the processing in a transport path, and supports the object to be transported;
A second support member provided downstream of the processing position and supporting the object to be conveyed;
A first detection unit that is installed between the first support member and the second support member and detects a first detection result that is surface information of the conveyed object;
A second detection unit that is installed between the first support member and the second support member and downstream of the first detection unit and detects a second detection result that is surface information of the conveyed object. When,
A conveyance apparatus comprising: an attitude detection unit that detects an attitude of the object to be conveyed based on the first detection result and the second detection result. The posture detection unit detects a skew amount when the object to be conveyed is conveyed obliquely with respect to the conveyance direction,
The transport apparatus according to claim 1, further comprising a head unit rotation control unit configured to rotate the head unit around a vertical axis with respect to the transport direction based on the skew amount. The posture detection unit detects a skew amount when the object to be conveyed is conveyed obliquely with respect to the conveyance direction,
3. The support member rotation control unit according to claim 1, further comprising a support member rotation control unit that tilts the first support member or the second support member around a travel axis with respect to the transport direction based on the skew amount. Conveying device. A third detection unit that is installed at least one upstream of the first detection unit and detects a third detection result that is surface information of the conveyed object;
4. The transport device according to claim 1, further comprising a moving unit that moves the head unit in an orthogonal direction based on the first detection result and the third detection result. 5. The surface information is a pattern that the conveyed object has,
5. The transport device according to claim 1, wherein the first detection unit and the second detection unit detect the first detection result and the second detection result based on the pattern. 6. The pattern is generated by interference of light applied to the uneven shape formed on the transported object,
The transport apparatus according to claim 5, wherein the first detection unit and the second detection unit detect the first detection result and the second detection result based on an image obtained by capturing the pattern.   The transport apparatus according to claim 5 or 6, wherein the first detection unit and the second detection unit detect a position of the transported object based on a result of detecting the pattern at two or more different timings.   The transport device according to claim 1, wherein the first detection unit is installed at a position closer to the first support member than the processing position.   The transport apparatus according to claim 1, wherein the object to be transported is long.   A liquid ejecting apparatus comprising the transport device according to claim 1. A transport unit for transporting the transported object, a head unit for processing the transported object,
A first support member that is provided upstream of the processing position where the head unit performs the processing in the transport path, supports the transported object, and is provided downstream of the processing position and supports the transported object. A posture detection method performed by a transfer device having a second support member
A first detection procedure for detecting a first detection result which is surface information of the object to be transported by a first detection unit disposed between the first support member and the second support member;
A second detection result that is surface information of the object to be transported by a second detection unit disposed between the first support member and the second support member and downstream of the first detection procedure. A second detection procedure for detecting
An attitude detection method including an attitude detection procedure for detecting an attitude of the conveyed object based on the first detection result and the second detection result.

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