JP7066985B2 - Transport device, liquid discharge device and attitude detection method - Google Patents

Description

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

Conventionally, there are known methods of performing various processes using a head unit. For example, a method of forming an image by a so-called inkjet method of ejecting ink from a print head is known. As described above, in the apparatus for processing the transported object, if the processing timing at which the processing is performed or the position where the transported object is transported is deviated, the processing result is also deviated.

Therefore, in order to improve the image quality of the image formed by the head unit, a method of detecting the amount of deviation of the recording medium is known. Specifically, there is known a method of detecting a lateral position change of a web (web), which is a recording medium used in a continuous paper printing system, by a sensor (see, for example, Patent Document 1).

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

One aspect of the present invention is to detect the posture of the object to be transported at the processing position.

In order to solve the above-mentioned problems, the transport device according to one aspect of the present invention is
A transport unit that transports the object to be transported and
A head unit that processes the object to be transported and
A first support member that is provided upstream of the processing position where the head unit performs the processing in the transport path and supports the object to be transported, and
A second support member provided downstream from the processing position and supporting the object to be transported, and a second support member.
A first detection unit installed between the first support member and the second support member to detect a first detection result which is surface information of the transported object, and a first detection unit.
A second detection unit installed between the first support member and the second support member and downstream of the first detection unit to detect a second detection result which is surface information of the object to be transported. When,
A posture detecting unit for detecting the posture of the object to be transported based on the first detection result and the second detection result is provided.
The posture detecting unit detects the amount of skew when the object to be transported is transported diagonally with respect to the transport direction.
A support member rotation control unit that tilts the first support member or the second support member is further provided around the traveling axis with respect to the transport direction based on the skew amount, and the transported object has a length. It is a scale ,
A third detection unit installed upstream of the first detection unit and detecting a third detection result which is surface information of the transported object, and a third detection unit.
Based on the first detection result and the third detection result, a moving unit for moving the head unit in an orthogonal direction is further provided .

The posture of the object to be transported at the processing position can be detected.

It is a schematic diagram which shows an example of the transfer apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows the whole structure example of the transfer 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 configuration example which realizes the posture 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 the functional structure of the posture 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 calculation result example of the correlation calculation which concerns on one Embodiment of this invention. It is a schematic diagram which shows the structural example for detecting the posture of the conveyed object which concerns on one Embodiment of this invention. It is a figure which shows the example of the deviation amount in the orthogonal direction which concerns on one Embodiment of this invention. It is a flowchart which shows the posture detection processing example by the transfer apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows an example of the hardware composition of the control part which concerns on one Embodiment of this invention. It is a block diagram which shows an example of the hardware composition 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 composition 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 the functional structure of the transport device which concerns on one Embodiment of 1st modification of this invention. It is a timing chart which shows the detection example of the position of the object to be conveyed by the transfer apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows the hardware configuration example for realizing the moving part which concerns on one Embodiment of this invention. It is a conceptual diagram which shows the example of rotating the head unit by the transport device which concerns on one Embodiment of 2nd Embodiment of this invention. It is a figure which shows an example of the hardware configuration in the 1st comparative example. It is a functional block diagram which shows an example of the functional structure of the transport device which concerns on one Embodiment of 2nd Embodiment of this invention. It is a schematic diagram which shows the whole structure example of the transfer apparatus which concerns on one Embodiment of 3rd Embodiment of this invention. It is a schematic diagram which shows the rotation control example of the support member by the transport device which concerns on one Embodiment of 3rd Embodiment of this invention. It is a flowchart which shows the skew correction processing example by the transport device which concerns on one Embodiment of 3rd Embodiment of this invention. It is a functional block diagram which shows an example of the functional structure of the transport device which concerns on one Embodiment of 3rd Embodiment of this invention. It is a schematic diagram which shows the modification of the whole structure of the transfer apparatus which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the present specification and the drawings, the components having substantially the same functional configuration are designated by the same reference numerals, and duplicate description will be omitted.

<First Embodiment>
<Overall configuration example>
Hereinafter, a case where the transport device is provided with a liquid discharge device and the head unit of the liquid discharge device is a liquid discharge head unit that performs a process of discharging liquid to a transported object will be described as an example.

FIG. 1 is a schematic view showing an example of a transport device according to an embodiment of the present invention. For example, the liquid discharge device, which is an example of the transfer device, is an image forming device as shown in the figure. In such an image forming apparatus, the discharged liquid is a recording liquid such as water-based or oil-based ink. Hereinafter, an example in which the liquid discharge device is the image forming device 110 will be described.

The object to be transported is, for example, a recording medium or the like. In the illustrated example, the image forming apparatus 110 ejects a liquid to the web 120, which is an example of a recording medium conveyed by a roller 130 or the like, to form an image. Further, the web 120 is a so-called continuous paper printing medium or the like. That is, the web 120 is a roll-shaped paper or the like that can be rolled up. Hereinafter, an example in which the transported 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 direction shown in the drawing (hereinafter referred to as “transport direction 10”). Further, in the figure, the direction orthogonal to the transport direction 10 is an example in which the orthogonal direction 20 is used. Further, in this example, the image forming apparatus 110 is an inkjet printer that ejects four colors of inks of black (K), cyan (C), magenta (M), and yellow (Y) to form an image on the web 120. be.

Further, in the following description, as shown in the figure, the rotation around the axis perpendicular 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 called "pitch rotation (Pitch) RP".

FIG. 2 is a schematic view showing an overall configuration example of a transport device according to an embodiment of the present invention. FIG. 2 is a schematic view of an example in which an image forming apparatus is used as an example of a conveying apparatus. As shown in the figure, the image forming apparatus 110 has four liquid ejection head units for ejecting inks of four colors.

Each liquid discharge head unit discharges each liquid of each color to the web 120 transported in the transport direction 10. Further, it is assumed that the web 120 is conveyed by two pairs of nip rollers, rollers 230 and the like. The roller 230 is a roller that is given a driving force by a driving motor to drive the web 120, and is an example of a transport unit. Hereinafter, of the two pairs of nip rollers, the nip roller installed upstream of each liquid discharge head unit is referred to as "first nip roller NR1". On the other hand, the nip roller installed downstream from the first nip roller NR1 and each liquid discharge head unit is referred to as "second nip roller NR2".

Each nip roller rotates across the web 120, as shown. As described above, each nip roller and roller 230 is a mechanism or the like that conveys the web 120 in a predetermined direction.

Further, it is desirable that the web 120 is long. Specifically, it is desirable that the length of the web 120 is longer than the distance between the first nip roller NR1 and the second nip roller NR2. Furthermore, the object to be transported is not limited to the web 120. That is, the transported object may be a paper that is folded and stored, so-called "Z paper" or the like.

In the overall configuration example shown below, it is assumed that 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).

The 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, the 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 the 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 those shown in the figure.

Each liquid ejection head unit performs a process of ejecting ink of each color to a predetermined portion of the web 120 based on image data or the like. Further, the processing position (hereinafter referred to as “discharge position”) in which each liquid ejection head unit performs the processing of ejecting ink is substantially equal to the position where the liquid ejected from the liquid ejection head lands on the web 120, that is, the liquid. It is directly under 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, the 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”). Further, 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 controller 520 connected to each liquid ejection head unit controls the processing timing of each liquid ejection head unit to eject ink.

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

Further, in the illustrated example, a plurality of rollers are installed for the liquid discharge head unit. As shown in the figure, a plurality of rollers are installed, for example, upstream and downstream with each liquid discharge head unit interposed therebetween.

Specifically, in the transport path of the web 120, a roller (hereinafter referred to as “first roller”) for supporting the web 120 is installed on the upstream side of each discharge position for each liquid discharge head unit. Further, a roller (hereinafter referred to as "second roller") for supporting the web 120 is installed on the downstream side from each discharge position. When the first roller and the second roller are installed in this way, so-called "fluttering" can be reduced at each discharge position. The first roller and the second roller are, for example, driven rollers. Further, the first roller and the second roller may be rollers rotated by a motor or the like.

The first roller, which is an example of the first support member, and the second roller, which is an example of the second support member, do not have to be rotating bodies such as driven rollers. 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 a pipe or a shaft having a circular cross section. In addition, the first support member and the second support member may be a curved plate or the like whose portion in contact with the object is arcuate. Hereinafter, an example will be described in which the first support member is the first roller and the second support member is the second roller.

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

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

In FIG. 2, for example, two or more sensor devices for detecting the position of the web in the transport direction, the orthogonal direction, or both directions are installed in each liquid discharge head unit. The sensor device includes a sensor that utilizes pneumatic pressure, ultrasonic waves, or the like. Alternatively, the sensor device includes an optical sensor or the like that utilizes light such as visible light, laser, or infrared light. The optical sensor may be, for example, a CCD (Charge Coupled Device) camera, a CMOS (Complementary Metal Oxide Sensor) camera, or the like. That is, the sensor device includes, for example, a sensor capable of detecting 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 the relative position, the moving speed, the moving amount, or a combination thereof among the 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 shown in the figure, the liquid discharge head unit is, for example, a line type head unit.

For example, in the black liquid discharge head unit 210K, four heads 210K-1, 210K-2, 210K-3 and 210K-4 are arranged in a staggered manner in the orthogonal direction 20. For example, the head 210K-1 has a shape as shown in FIG. 3 (B). As a result, the black liquid ejection head unit 210K forms an image with black ink in the width direction (that is, the orthogonal direction 20) of the region (so-called printing region) where the image is formed on the web 120. can do. The configurations of the other liquid discharge head units 210C, 210M and 210Y are the same as those of the black liquid discharge head unit 210K, and the description thereof will be omitted.

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

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

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

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 has a configuration in which a pattern or the like formed on the transported object is imaged when the transported object is irradiated with light from a light source. The pattern is an example of surface information of the object to be transported. Specifically, the sensor device SEN first includes a laser light source LD as a light source. It also has an optical system 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 of FIG. 5 is a CMOS image sensor. Further, the sensor device SEN has a telecentric imaging optical system (TO) for forming a focused image on the CMOS image sensor.

For example, the optical sensor OS captures a pattern or the like formed on the object to be transported. 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, the controller 520 calculates the relative position and the like between one optical sensor OS and the other optical sensor based on the movement of the correlation peak position calculated by the correlation calculation or the like. In the illustrated example, the size of the sensor device SEN is 15 × 60 × 32 [mm] in width W × depth D × height H. The details of the correlation calculation will be described later.

The CMOS image sensor is an example of hardware that realizes an image pickup unit. In this example, the hardware that performs the correlation calculation is described as the controller 520, but the correlation calculation may be executed by the FPGA circuit mounted on any of the sensor devices.

The control circuit 52 controls an optical sensor or the like inside the sensor device SEN. Specifically, the control circuit 52 outputs, for example, 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 controls so that the two-dimensional image data can be acquired from the sensor device SEN. Then, the control circuit 52 sends the two-dimensional image data imaged and generated 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. It is desirable that the storage device 53 has a configuration in which the two-dimensional image data sent from the control circuit 52 can be divided and stored in different storage areas.

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

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

The control circuit 52 and the controller 520 are, for example, a CPU (Central Processing Unit), an electronic circuit, or the like. The control circuit 52, the storage device 53, the storage device 55, and the controller 520 do not have to 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 have the same memory.

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

The detection unit 52A is composed of, for example, an image pickup unit 16A, an image pickup 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, and is composed of an image pickup unit 16B, an image pickup 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.

As shown in the figure, the image pickup unit 16A images the web 120 transported in the transport direction 10. The image pickup unit 16A is realized by, for example, an optical sensor OS (FIG. 4).

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

The image capture unit 142A acquires image data captured by the image pickup unit 16A.

The shutter control unit 141A controls the timing at which the image pickup unit 16A takes an image.

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

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

Further, the calculation unit 53F outputs data of a 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 at which the shutter is released so that the image data indicating the “A position” and the image data indicating the “B position” are imaged with a time difference Δt. The calculation unit 53F is realized by, for example, a controller 520 (FIG. 2) or the like.

The web 120 is a member having a scattering property on the surface or inside. Therefore, when the web 120 is irradiated with the laser beam, the reflected light is diffusely reflected. Due to this diffuse reflection, a pattern is formed on the web 120. That is, the pattern is a spot called "speckle", a so-called speckle pattern or the like. The pattern is an example of the surface information of the web 120. Therefore, when the web 120 is imaged, image data showing the pattern can be obtained. Since the position of the pattern can be known from this 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 the 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 amount of movement of the web 120. Then, the transport device can calculate the movement amount by calculating the movement amount per unit time.

As shown in the figure, the image pickup unit 16A and the image pickup unit 16B are installed at regular intervals in the transport direction 10. Then, the web 120 is imaged at each position via the image pickup unit 16A and the image pickup unit 16B.

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

Δt = L / V (1)

In the above equation (1), since the relative distance L is the distance between the sensor device SENK1 and the sensor device SENK2, it can be specified by measuring the distance 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 respective images captured by the detection unit 52A and the detection unit 52B. Hereinafter, the image data generated by the cross-correlation operation is referred to as a “correlation image”. For example, the image forming apparatus calculates at least one of a relative position in the orthogonal direction and a relative position in the transport direction between the two image data based on the correlated image.

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

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

In the above equation (2), the image data "D1 (n)", that is, the image data indicating the image captured at the "A position" is referred to as "D1". Similarly, in the above equation (2), the image data “D2 (n)”, that is, the image data indicating the image captured at the “B position” is referred to as “D2”. Further, 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, the image data showing the correlated image is obtained. When the image data D1 and D2 are two-dimensional image data, the image data showing the correlated image is the two-dimensional image data. Further, when the image data D1 and D2 are one-dimensional image data, the image data showing the correlated image is one-dimensional image data.

In the correlated image, for example, when a broad luminance distribution becomes a problem, a phase-limited correlation method may be used. The phase-limited correlation method is, for example, a calculation shown 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 in the complex amplitude. Further, all the amplitudes are set to "1".

In this way, the image forming apparatus can calculate the deviation amount ΔD (n) based on the correlated image even if the luminance distribution is broad.

The correlation image shows the correlation between the image data D1 and D2. Specifically, the higher the degree of coincidence of the image data D1 and D2, the steeper the peak, that is, the brightness that becomes the so-called correlation peak is output at the position closer to the center of the correlation image. Then, when the image data D1 and D2 match, the positions of the center and the peak of the correlated 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 captured 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. The calculation unit 53F may calculate the movement speed instead of the movement amount.

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

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 a storage device 55 or the like.

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

Further, 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 at the position of the sensor, the amount of movement, the moving speed, a combination thereof, or the like when the correlation calculation is performed according to the configuration as shown in the figure. ..

Specifically, as shown in the figure, 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, and an operation. It is configured to have a unit CAL and a conversion result storage unit MEM.

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

The Fourier transform unit FT1a for the orthogonal direction performs a 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 of 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 converted in this way 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 has a configuration including a Fourier transform unit FT2a for the orthogonal direction, a Fourier transform unit FT2b for the transport direction, and a complex conjugate unit FT2c.

The Fourier transform unit FT2a for the orthogonal direction performs a 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 of 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 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 correlated image data generation unit DMK has 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. Correlated image data is generated based on the conversion result of the data D2.

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

The integration 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 by the integration unit DMKa. When the two-dimensional inverse Fourier transform is performed in this way, the correlated 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.

The peak position search unit SR searches for a peak position having a peak brightness (peak value) having the steepest (that is, a steep rise) in the generated correlated image data. First, a value indicating the intensity of light, that is, the magnitude of brightness is input to the correlated image data. The brightness is input in a matrix.

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

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

FIG. 8 is a diagram showing an example of a method for searching for a peak position in a correlation calculation according to an embodiment of the present invention. In the figure, the horizontal axis indicates the position in the transport direction in the correlated image data. On the other hand, the vertical axis indicates the brightness of the pixels indicated by the correlated image data.

Hereinafter, among the brightnesses indicated by the correlated image data, three data of the first data value q1, the second data value q2, and the third data value q3 will be described as an example. That is, in this example, the peak position search unit SR searches for the peak position P on 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 difference in the luminance for each pixel indicated by the correlated image data. Then, the peak position search unit SR extracts a combination of data values having the largest difference value among the calculated differences. Next, the peak position search unit SR extracts a combination adjacent to the combination of data values having the largest difference value. In this way, the peak position search unit SR can extract three data as shown in the illustrated first data value q1, second data value q2, and third data value q3. Then, 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. By doing so, 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 sub-pixel processing. The position of the combination of data values having the largest difference value is the steepest position. Further, the sub-pixel processing may be processing other than the above processing.

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

FIG. 9 is a diagram showing an example of a calculation result of a correlation calculation according to an embodiment of the present invention. The figure shows the correlation intensity distribution of the cross-correlation function. In the figure, the X-axis and the Y-axis indicate the serial numbers of the pixels. A peak position such as the illustrated "correlation peak" is searched by the peak position search unit SR.

The calculation unit CAL calculates the relative position, movement amount, movement speed, etc. 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 correlated 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. The detection method of relative position, movement amount, movement speed, etc. is not limited to this. For example, the image forming apparatus 110 may detect a relative position, a moving amount, a moving speed, or the like as follows.

First, the image forming apparatus 110 binarizes the brightness of each of the first image data and the second image data. That is, the image forming apparatus 110 is set to "0" if the brightness is equal to or less than a preset threshold value, and is set to "1" if the brightness is larger than the threshold value. The image forming apparatus 110 may detect the relative position by comparing the first image data and the second image data binarized in this way.

In the figure, an example in which there is a fluctuation in the Y direction has been described, but when there is a fluctuation in the X direction, the peak position is generated at a position shifted in the X direction as well.

Further, the image forming apparatus 110 may detect a relative position, a moving amount, a moving speed, or the like by another detection method. For example, the image forming apparatus 110 may detect a relative position from each pattern reflected in each image data by so-called pattern matching processing or the like.

By performing the correlation calculation as described above, the image forming apparatus 110 can grasp the amount of deviation indicating how much the object to be conveyed deviates from a predetermined position in the transport direction, the orthogonal direction, or both directions.

<Posture detection example and configuration example>
FIG. 10 is a schematic diagram showing a configuration example for detecting the posture of the object to be transported according to the 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 roller CR1K for black, the sensor device SENK1, the sensor device SENK2, and the second roller CR2K for black corresponding to the black liquid discharge head unit in FIG. 2.

For example, the sensor device SENK2 is set between the black first roller CR1K and the black second roller CR2K and downstream of the sensor device SENK1. Further, the sensor device SENK2 detects at least a part of the same pattern as the pattern detected by the sensor device SENK1 at a timing. 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 amount of deviation of the web 120 in the orthogonal direction 20 between the two detection positions. That is, the figure 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 amount of deviation a plurality of times and stores it in the storage apparatus 55 of FIG.

FIG. 11 is a diagram showing an example of the amount of deviation in the orthogonal direction according to the embodiment of the present invention. The figure is an example of the result of plotting the amount of deviation detected 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 in succession 10 times, and acquires the deviation amount for 1000 times in total. Then, by plotting the amount of deviation for 1000 times in chronological order, the data as shown in the figure can be generated.

As shown in the figure, the amount of deviation is a component that is almost constant with respect to time (hereinafter referred to as "diagonal component ER1") and a component whose amount varies periodically with respect to time (hereinafter referred to as "meandering component ER2"). ") Is often included.

In the example shown in FIG. 10, the skew component ER1 is generated due to the so-called skew state 120A or the like in which the web 120 is transported diagonally with respect to the transport direction 10.

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

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

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

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

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

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

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

In step SP03, the controller 520 performs a correlation calculation 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 amount of displacement of the transported object generated 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 transfer device can acquire a plurality of deviation amounts.

In step SP04, the transport device detects the posture of the object to be transported. For example, when the transport device calculates the skew component ER1 and the meander component ER2 as shown in FIG. 11 by averaging a plurality of deviation amounts, the conveyed object is in the skew state 120A, the meander state 120B, or both. It is possible to detect whether or not the posture includes the posture.

The process as shown in the figure may be performed while the transfer device is performing the process 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 on the object to be transported during image formation.

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

FIG. 13 is a block diagram showing an example of the hardware configuration of the control unit according to the embodiment of the present invention. For example, the controller 520 is composed of a host device 71 such as an information processing device and a main body side control device 72. In the illustrated example, the controller 520 controls the transported object to form an image under the control of the main body side control device 72 based on the image data and the control data input from the host device 71.

The host device 71 is, for example, a PC (Personal Computer) or the like. Further, the main body side control device 72 has 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. Then, when the control data is received, the print conditions and the like indicated by the control data are input to the printer controller 72C, and the printer controller 72C stores the print conditions and the like by the registers and the like. Next, the printer controller 72C controls the printer engine 72E based on the control data, and performs image formation according to the print job data, that is, the control data.

The printer controller 72C has 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. Further, 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 unit and a control unit.

The print control device 72Cc transmits / receives data indicating a command, status, or the like to / from the printer engine 72E based on the control data transmitted from the host device 71. As a result, 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 the image data from the host device 71 via the plurality of data lines. Next, the printer engine 72E forms an image of each color based on the control by the printer controller 72C.

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

FIG. 14 is a block diagram showing an example of the hardware configuration of the data management device included in the control unit according to the embodiment of the present invention. For example, a 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, duplicate description will be omitted.

The data management device 72EC has 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.

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

It is desirable that the storage device 72ECm has a capacity of storing about 3 pages of image data. When the image data of about 3 pages can be stored, the storage device 72ECm can store the image data input from the host device 71, the image data during image formation, and the image data for next image formation.

FIG. 15 is a block diagram showing an example of the hardware configuration of the image output device included in the control unit according to the 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, which are liquid discharge head units of each color. It has a unit 210Y.

The output control device 72Eic outputs image data of each color to the liquid discharge head unit of each color. That is, 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 discharge head units simultaneously or individually. That is, the output control device 72Eic receives the input of the timing and controls to change the timing of discharging the liquid to each liquid discharge head unit. The output control device 72Eic may control any of the liquid discharge head units based on the control signal input from the printer controller 72C. Further, the output control device 72Eic may control any of the liquid discharge head units based on an operation by the user or the like.

The main body side control device 72 has different routes for inputting image data from the host device 71 and a route used for transmission / reception between the host device 71 and the main body side control device 72 based on the control data. This is an example.

As described above, the posture of the transported object can be detected by performing the processing as shown in FIGS. 4 to 12.

<First modification>
FIG. 16 is a functional block diagram showing an example of the functional configuration of the transport device according to the first embodiment of the present invention. Hereinafter, the functional configuration of the cyan liquid discharge head unit 210C will be described as an example. As shown in the figure, the image forming apparatus 110 has, for example, a functional configuration including a first detection unit 52A, a third detection unit 52C, a fourth detection unit 52D, a posture detection unit 56F, and a calculation unit 53F. .. Further, as shown in the figure, it is desirable that the image forming apparatus 110 has a functional configuration further including a moving unit 110F3 and a control unit 54F. Hereinafter, the illustrated functional configuration will be described as an example.

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

The first detection unit 52A detects the surface information of the web 120 by, for example, the black roller-to-roller INTK1 between the black first roller CR1K and the black second roller CR2K. The first detection unit is realized by the sensor device SENK1 shown in FIG. Since the description of the detection unit is the same as that in FIG. 6, the description thereof will be omitted. The first detection unit 52A does not have to be the sensor device SENK1, and may be realized by the sensor device SEN arranged upstream of the sensor device SENC1 arranged between the cyan rollers.

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

The fourth detection unit 52D is an inter-cyan roller INTC1 between the first roller CR1C for cyan and the second roller CR2C for cyan, and detects the surface information of the web 120 downstream from the third detection unit. 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 calculation on the detection results of the third detection unit and the fourth detection unit, and calculates the deviation amount in the orthogonal direction. Since the functions of the deviation amount storage unit 55F and the posture detection unit 56F are the same as those in FIG. 6, the description thereof will be omitted.

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 53F 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 discharge head unit 210C in the orthogonal direction from the calculation results 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 53F can calculate how much the movement amount of the web in the transport direction deviates from the ideal movement amount L2. That is, the calculation unit 53F can calculate the discharge timing of the cyan liquid discharge head unit 210C from the calculation results 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 the actuator ACT described later and controls the landing position of the cyan liquid. The moving unit 57F is configured by, for example, an actuator controller CTL described later. The function of the moving unit 57F may be configured not only by the actuator controller CTL but also by the controller 520. Further, it may be configured by the controller 520.

The control unit 54F controls the discharge timing by the cyan liquid discharge head unit 210C.

FIG. 17 is a timing chart showing an example of detecting the position of the object to be transported by the transport device according to the embodiment of the present invention.

The image forming apparatus 110 calculates the amount of variation in the position of the object to be transported, etc., based on the plurality of sensor data. Specifically, the image forming apparatus outputs a calculation result indicating the amount of fluctuation based on the first sensor data S1 and the second sensor data S2. In the detection shown in the figure, the first detection result, that is, the sensor data indicating the detection result output by the detection unit upstream is the first sensor data S1. On the other hand, the third detection result, that is, the sensor data indicating 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 discharge head unit 210C will be described. In this example, the sensor device SENK1 outputs the first sensor data S1 indicating the first detection result, while the sensor device SENC1 outputs the 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". Further, it is assumed that the moving time elapsed for the conveyed object to be 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".

Further, the sampling interval by the sensor is set to "A". Further, the number of samplings between the sensors is set to "n". In this case, the number of samplings is calculated as "n = T2 / A".

The illustrated calculation result, that is, the fluctuation amount is defined as "ΔX". For example, as shown in the figure, when the detection cycle is "0", the fluctuation amount includes the first sensor data S1 before the travel time "T2" and the second sensor data S2 having 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 discharge head unit 210C in the orthogonal direction. By doing so, even if the position of the transported object fluctuates, the image forming apparatus 110 can accurately process the transported object. Further, if the fluctuation amount is calculated based on the sensor data between the two points with the most upstream sensor, the fluctuation amount can be calculated without integrating the position information of each sensor. Therefore, by doing so, the accumulation of detection errors by each sensor can be reduced.

Further, the sensor data is not limited to the detection result detected by the sensor installed on the upstream side of the moving liquid discharge head unit. That is, the sensor may be a sensor installed on the upstream side of the liquid discharge head unit to be moved.

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

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

In this way, the image forming apparatus 110 controls the movement of the liquid discharge head unit based on the fluctuation amount calculated from the plurality of sensor data, 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 each discharge. It is desirable that the position is close to the position. If the detection can be performed at a position close to each discharge position, the distance between the processing position and the sensor becomes short. Then, when the distance between the processing position and the sensor becomes short, the error in detection becomes small. 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.

Further, among the sensor devices used for controlling the discharge timing 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 the discharge 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, it is desirable that the sensor device SENC1 is between the cyan discharge position PC and the position where the first cyan roller CR1C for cyan is installed (hereinafter referred to as "upstream section for cyan 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 transported in the orthogonal direction, the transport direction, or both directions by the sensor upstream. Therefore, the image forming apparatus 110 can calculate the processing timing at which each liquid discharge head unit discharges the liquid, the amount of movement of the head unit, or both.

That is, since the web 120 is conveyed to the ejection position after the position of the object to be conveyed is detected upstream, the image forming apparatus 110 calculates the processing timing or calculates the processing timing while the web 120 is conveyed to the ejection position. The head unit can be moved and the like. 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 under each liquid discharge head unit, the position where the processing is performed may shift due to the delay of the control operation or the like. .. Therefore, if the position where the sensor device for outputting the second sensor data is installed is upstream from each discharge position, the image forming apparatus 110 can reduce the deviation and perform the processing with high accuracy. Further, the vicinity of each discharge position may be restricted to the position where the sensor or the like is installed. Therefore, it is desirable that the position where the sensor is installed is 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 under each of the liquid discharge head units. When the sensor is directly underneath, there is an effect that the accurate movement amount underneath can be detected by the sensor. For example, if the control operation can be performed quickly, it may be desirable that the sensor is located closer to the position directly under each liquid discharge head unit. In addition, if the error is acceptable, the position of the sensor is directly under each liquid discharge head unit or between each first roller and each second roller, and from directly under each liquid discharge head unit. It may be a downstream position or the like.

FIG. 18 is a schematic view showing a hardware configuration example for realizing a moving portion according to an embodiment of the present invention. For example, the moving unit 110F3 is realized by hardware as shown in the figure. Hereinafter, as illustrated, a hardware configuration example for moving the cyan liquid discharge head unit 210C will be described.

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. Then, the actuator controller CTL that controls the actuator ACT is connected to 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 or the like. Then, the actuator controller CTL position-controls the cyan liquid discharge head unit 210C.

The fluctuation amount calculated as shown in FIG. 17 is input to the actuator controller CTL. Then, the actuator controller CTL moves the cyan liquid discharge head unit 210C by the actuator ACT so as to compensate for the fluctuation of the position of the web 120. Specifically, in the illustrated example, the fluctuation amount based on the plurality of detection results is the fluctuation “Δ”. Therefore, in this example, the actuator controller CTL moves the cyan liquid discharge head unit 210C in the orthogonal direction 20 so as to compensate for the fluctuation Δ.

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

As described above, when the moving unit 110F3 is present, the image forming apparatus 110 determines the amount of change in the position of the object to be transported in the orthogonal direction, that is, the amount of deviation, which is calculated based on the first detection result and the third detection result. It is possible to compensate and process the transported object with high accuracy. In particular, the image forming apparatus 110 can compensate for the amount of deviation during image forming by the moving unit 110F3.

Further, by using the third detection unit as a detection unit for detecting the detection result used in the posture detection unit, it is possible to efficiently compensate for the deviation amount.

<Second Embodiment>
The second embodiment is configured to further include a head unit rotation control unit that rotates the head unit in a yaw manner, in addition to the configuration of the first embodiment. Hereinafter, the points different from those of the first embodiment will be mainly described, and duplicate description will be omitted.

FIG. 19 is a conceptual diagram showing an example of controlling the rotation of the head unit by the transport device according to the second embodiment of the present invention. Hereinafter, the black liquid discharge head unit 210K will be described as an example. In the figure, the black liquid discharge head unit 210K before the rotation control is performed (before the rotation control is performed, it is assumed that the state is adjusted to the state where there is no skew) is shown as "pre-control head unit HU1". .. On the other hand, in the figure, the black liquid discharge head unit 210K after the rotation control is performed is shown as "the controlled head unit HU2".

Further, the position where the black ink is ejected by the pre-control head unit HU1 and the liquid lands on the object to be transported is referred to as "pre-control landing position PK1". On the other hand, the position where the black ink is ejected by the controlled post-head unit HU2 and the liquid lands on the object to be transported is referred to as "controlled post-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 distance between the sensors of the sensor device SENK1 and the sensor device SENK2 is referred to as "ΔLx". The distance between sensors ΔLx can be specified by measuring the distance between sensors in advance.

Further, in the following description, it is assumed that the web 120 is in an oblique state 120A as shown in the figure. Then, it is assumed that the rotation control of the black liquid discharge head unit 210K is performed centering on the end portion P0 (hereinafter, simply referred to as “end portion P0”) of the web 120 in the oblique state 120A.

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

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

yd = y2-y1 (4)

Assuming that the angle formed by the web edge in the slanted state and the web edge in the slanted state 120A is "θ", "yd" can be specified by the calculation as shown in the following equation (5).

yd = ΔLx × tanθ (5)

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

θ = tan ^-1 (yd / ΔLx) (6)

Then, "P0y" can be expressed as the following equation (7).

P0y = yd × (P0x / ΔLx)
= (Y2-y1) × (P0x / ΔLx)
= (ΔLx × tanθ) × (P0x / ΔLx)
= P0x × tanθ (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-rotate RY as shown in the figure.

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

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

It is desirable that the rotation control as shown in the figure is 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, the posture detection and the like may be performed while the processing is being performed by the head unit.

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

<Comparison example>
FIG. 20 is a diagram showing an example of the hardware configuration in the first comparative example. In the illustrated first comparative example, the position of the web 120 is detected before each liquid discharge head unit is conveyed to the discharge position. In this comparative example, the position where the sensor is installed is a position that is "200 mm" from directly below the liquid discharge head unit to the upstream. Based on the detection result in this case, the image forming apparatus according to the first comparative example moves the liquid discharge head unit to compensate for the fluctuation of the position of the web 120.

In the first comparative example, since the fluctuation is compensated based on the detection result detected 200 mm upstream from the liquid discharge head unit, the detection error is large and color shift 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, the rotation control in the first comparative example is difficult as shown in FIG.

<Function configuration example>
FIG. 21 is a functional block diagram showing an example of the functional configuration of the transport device according to the second embodiment of the present invention. Compared with the first embodiment, the second embodiment is different in that the head unit rotation control unit 110F4 is provided. Hereinafter, the points different from those of the first embodiment will be mainly described, and duplicate description will be omitted.

The head unit rotation control unit 110F4 rotates the black liquid discharge head unit 210K about the axis perpendicular to the transport direction 10 (that is, yaw rotation RY) based on the skew amount detected by the attitude detection unit 56F. Let me. For example, the head unit rotation control unit 110F4 is realized by an actuator or the like having a degree of freedom in yaw rotation RY. The function of the posture detection unit 56F is the same as that described with reference to FIG. 6, and is therefore omitted.

Based on the amount of skew detected by the attitude detection unit 56F, the image forming apparatus 110 causes, for example, the head unit to rotate in yaw. In this way, the image forming apparatus 110 can accurately process the transported object even if skewing or the like occurs.

<Third Embodiment>
FIG. 22 is a schematic view showing an overall configuration example of the transport device according to the third embodiment of the present invention. The third embodiment is different in that an actuator for tilting the second roller is added to the configuration of the first embodiment. Hereinafter, the points different from those of the first embodiment will be mainly described, and duplicate description will be omitted.

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

The adjusting 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 adjusting device 521 may be a plurality of devices.

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

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

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

When the inclination of the second roller CR2K for black changes, the amount of skewing often changes. Therefore, the image forming apparatus 110 changes the inclination of the second roller CR2K for black by the adjusting apparatus 521 so that the amount of skew is adjusted to be smaller than a predetermined amount.

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

The image forming apparatus 110 may control the movement of 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 rolled and rotated RR.

Further, the image forming apparatus 110 is not limited to the second support member, and may control the rotation of 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 that the image forming apparatus 110 performs the following overall processing when the web 120 is replaced or the like.

FIG. 24 is a flowchart showing an example of skew correction processing by the transport device according to the third embodiment of the present invention. Hereinafter, the same processing as in the first embodiment is designated by the same reference numerals and duplicated description will be omitted. Compared with the first embodiment, the third embodiment is different in that the processing of steps SP31 to 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 replaced, the image forming apparatus 110 conveys the web 120 as an adjustment mode. Therefore, in this example, when the adjustment mode is set, the image forming apparatus 110 determines that the adjustment is to be performed (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 the adjustment is not 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 elapsed since the adjustment mode is set (hereinafter, simply referred to as “elapsed time”).

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

In step SP33, the image forming apparatus 110 determines whether or not the skew amount is equal to or less than a predetermined amount. Next, when the skew amount is equal to or less than a predetermined amount (YES in step SP33), the image forming apparatus 110 ends the process. In this case, since the amount of skew is sufficiently small, adjustment is not necessary. On the other hand, if the amount of skew is not equal to or less than a 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 or not 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. Then, the image forming apparatus 110 compares the elapsed time with the predetermined time, and 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 image forming apparatus 110 proceeds to step SP36.

In step S35, the image forming apparatus 110 controls the tilting of the support member. That is, the image forming apparatus 110 controls to tilt the support member, for example, as shown in FIG. 27, based on the amount of skew detected in step SP04. In this way, the image forming apparatus 110 controls the support member to be tilted so that the amount of skew is small.

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, such as by sending 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 amount of skew becomes a small value. Therefore, the image forming apparatus 110 can perform processing such as image forming with less skewing. Therefore, the image forming apparatus 110 can accurately process the object to be conveyed.

<Function configuration example>
FIG. 25 is a functional block diagram showing an example of the functional configuration of the transport device according to the third embodiment of the present invention. Compared with the first embodiment, the third embodiment is different in that the support member rotation control unit 110F5 is provided. Hereinafter, the points different from those of the first embodiment will be mainly described, and duplicate description will be omitted.

The support member rotation control unit 110F5 rotates the black liquid discharge head unit 210K around the traveling axis (that is, roll rotation RR) with respect to the transport direction 10 based on the skew amount detected by the attitude detection unit 56F. Let me. For example, the support member rotation control unit 110F5 is realized by an actuator or the like having a degree of freedom in roll rotation RR as shown in FIG. 23. The function of the posture detection unit 56F is the same as that described with reference to FIG. 6, and is therefore omitted.
Based on the amount of skew detected by the posture detection unit 56F, the image forming apparatus 110 causes, for example, a second support member or the like to rotate RR. In this way, the image forming apparatus 110 can reduce the skew amount to a small value and perform processing on the transported object with high accuracy.

<Modification example>
FIG. 26 is a schematic view showing a modified example of the overall configuration of the transport device according to the embodiment of the present invention. Compared with FIG. 2, in the illustrated configuration, the arrangement of the first support member and the second support member is different. As shown in the figure, 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 shared. The first support member and the second support member may be combined with a roller or a curved plate.

Further, the present invention can be applied to an apparatus that performs some processing by using line-shaped head units arranged in an orthogonal direction.

For example, the embodiment according to the present invention may be a transfer device or the like in which a head unit emits a laser and the substrate to be transported is subjected to patterning processing by the laser. Specifically, the transport device first has laser heads arranged in a line in an orthogonal direction. Then, the transport device detects the position of the substrate and the like, and moves the head unit or the like based on the detection result. Further, in this example, the processing position is the position where the laser irradiates the substrate.

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

Further, the transport device does not have to have a plurality of head units. That is, the present invention is applicable when the processing is continuously performed at the reference position with respect to the transported object.

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

Further, the light source may be a light source having a single wavelength or a light source having a broad wavelength.

In the above embodiment, an image forming apparatus for forming an image using a liquid ejection head unit having four colors of black, cyan, magenta, and yellow has been described as an example. However, the image forming apparatus may be configured to include, for example, a plurality of black liquid ejection head units to form an image.

Further, the object to be transported is not limited to a recording medium such as paper. The material to be transported may be any material to which liquid can adhere. For example, the material to which the liquid can be attached may be paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, or a combination thereof, as long as the liquid can be attached even 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 devices having the same housing, and the magenta liquid discharge head unit 210M and the yellow liquid discharge head unit 210Y are devices having the same housing, both of which are included. It may be realized by a transport system.

Further, each process may be performed in parallel, redundantly or distributed by a plurality of information processing devices included in the transport system.

Further, in the transfer device, the liquid discharge device and the transfer system provided with the transfer device according to the present invention, the liquid is not limited to ink, but may be another type of recording liquid, fixing treatment liquid, or the like. That is, the transfer device, the liquid discharge device and the transfer system including the transfer device according to the present invention may be applied to a device that discharges a type of liquid other than ink.

Therefore, the transfer device, the liquid discharge device and the transfer system including the transfer device according to the present invention are not limited to the process of forming an image. For example, the formed object may be a three-dimensional model or the like.

Further, in the embodiment of the present invention, it may be realized by a program for causing a computer such as a transfer device, a liquid discharge device provided with the transfer device, and a transfer system to execute a posture detection method. Therefore, when the posture detection method is executed based on the program, the arithmetic unit and the control unit of the computer perform the arithmetic and control based on the program in order to execute each process. In addition, the storage device of the computer stores the data used for the processing based on the program in order to execute each processing.

The program can also 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. In addition, the program can be distributed over telecommunications lines.

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

110 Image Forming Device 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 Unexamined Patent Publication No. 2015-13476

Claims (8)

A transport unit that transports the object to be transported and
A head unit that processes the object to be transported and
A first support member that is provided upstream of the processing position where the head unit performs the processing in the transport path and supports the object to be transported, and
A second support member provided downstream from the processing position and supporting the object to be transported, and a second support member.
A first detection unit installed between the first support member and the second support member to detect a first detection result which is surface information of the transported object, and a first detection unit.
A second detection unit installed between the first support member and the second support member and downstream of the first detection unit to detect a second detection result which is surface information of the object to be transported. When,
A posture detecting unit for detecting the posture of the object to be transported based on the first detection result and the second detection result is provided.
The posture detecting unit detects the amount of skew when the object to be transported is transported diagonally with respect to the transport direction.
A support member rotation control unit that tilts the first support member or the second support member is further provided around the traveling axis with respect to the transport direction based on the skew amount.
The object to be transported is long and has a long length .
A third detection unit installed upstream of the first detection unit and detecting a third detection result which is surface information of the transported object, and a third detection unit.
A transport device further including a moving unit for moving the head unit in an orthogonal direction based on the first detection result and the third detection result . A transport unit that transports the object to be transported and
A head unit that processes the object to be transported and
A first support member that is provided upstream of the processing position where the head unit performs the processing in the transport path and supports the object to be transported, and
A second support member provided downstream from the processing position and supporting the object to be transported, and a second support member.
A first detection unit installed between the first support member and the second support member to detect a first detection result which is surface information of the transported object, and a first detection unit.
A second detection unit installed between the first support member and the second support member and downstream of the first detection unit to detect a second detection result which is surface information of the object to be transported. When,
A posture detecting unit for detecting the posture of the object to be transported based on the first detection result and the second detection result is provided.
The posture detecting unit detects the amount of skew when the object to be transported is transported diagonally with respect to the transport direction.
A support member rotation control unit that tilts the first support member or the second support member is further provided around the traveling axis with respect to the transport direction based on the skew amount.
The object to be transported is long and has a long length .
The surface information is a pattern possessed by the transported object.
The first detection unit and the second detection unit are transfer devices that detect the first detection result and the second detection result based on the pattern . The posture detecting unit detects the amount of skew when the object to be transported is transported diagonally with respect to the transport direction.
The transport device according to claim 1 or 2 , further comprising a head unit rotation control unit that rotates the head unit around an axis perpendicular to the transport direction based on the skew amount. The pattern is generated by the interference of light applied to the uneven shape formed on the object to be transported.
The transport device according to claim 2 , 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 device according to claim 4 , wherein the first detection unit and the second detection unit detect the position of the object to be transported based on the results of detecting the pattern at two or more different timings. The transport device according to any one of claims 1 to 5 , wherein the first detection unit is installed at a position closer to the first support member than the processing position. A liquid discharge device including the transport device according to any one of claims 1 to 6 . A transport unit that transports the object to be transported, a head unit that processes the object to be transported, and a head unit.
In the transport path, the head unit is provided upstream from the processing position where the processing is performed, and is provided with a first support member for supporting the transported object and downstream from the processing position to support the transported object. This is a posture detection method performed by a transport 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 arranged between the first support member and the second support member.
A second detection result, which is surface information of the object to be transported, in a second detection unit located between the first support member and the second support member and located downstream of the first detection procedure. The second detection procedure to detect
A posture detection procedure for detecting the posture of the object to be transported based on the first detection result and the second detection result is included.
In the posture detection procedure, the amount of skew when the object to be transported is transported diagonally with respect to the transport direction is detected.
Further provided with a support member rotation control procedure for tilting the first support member or the second support member around the traveling axis with respect to the transport direction based on the skew amount.
The object to be transported is long and has a long length .
The surface information is a pattern possessed by the transported object.
The first detection procedure and the second detection procedure are posture detection methods for detecting the first detection result and the second detection result based on the pattern .

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