JP2018154077A - Conveying apparatus, conveying system and processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of a processing position by a head unit. SOLUTION: A transport device having a head unit and processing a transported object by the head unit is installed for each head unit, and a position, a moving speed, and a moving amount of the transported object are installed. Alternatively, a detection unit that outputs a detection result indicating a combination of these, a statistical value calculation unit that calculates a statistical value of the position based on a plurality of the detection results, and a detection unit that calculates the statistical value based on the statistical value. The above problem is solved by providing a setting unit for setting a detection range for performing the above. [Selection diagram] Fig. 1

Description

  The present invention relates to a transport apparatus, a transport system, and a processing method.

  Conventionally, methods for performing various processes using a head unit are known. For example, a method of forming an image by a so-called ink jet method in which ink is ejected from a print head is known. A method for improving the print quality of an image printed on a print medium by this image formation is known.

  For example, a method of adjusting the position of the print head is known in order to improve print quality. Specifically, first, a position change in the lateral direction of a web that is a printing medium passing through a continuous paper printing system is detected by a sensor. A method of adjusting the position of the print head in the lateral direction so as to compensate for the position variation detected by this sensor is known (see, for example, Patent Document 1).

  However, for example, when improving the image quality of an image to be formed, it may be required to improve the liquid landing position. On the other hand, in the conventional technique, since the accuracy of the processing position where the processing is performed by the head unit is poor, there is a problem that the accuracy of the processing position such as the liquid landing position may be deteriorated.

  An object of one aspect of the present invention is to provide an apparatus that can improve the accuracy of a processing position of an apparatus that performs processing on an object to be conveyed using a head unit, such as an apparatus that discharges liquid.

In order to solve the above-described problem, a transport apparatus that includes a head unit and performs processing on a transported object by the head unit, which is an aspect of the present invention,
A detection unit that is installed for each head unit and outputs a detection result indicating the position, moving speed, moving amount, or a combination of the objects to be conveyed;
A statistical value calculation unit for calculating a statistical value of the position based on a plurality of the detection results;
And a setting unit configured to set a detection range in which the detection unit performs detection based on the statistical value.

  An apparatus capable of improving the accuracy of the processing position by the head unit can be provided.

It is the schematic which shows an example of the apparatus which discharges the liquid which concerns on one Embodiment of this invention. It is the schematic which shows the example of whole structure of the apparatus which discharges the liquid which concerns on one Embodiment of this invention. It is a figure which shows an example of the external shape of the liquid discharge head unit which concerns on one Embodiment of this invention. It is a block diagram which shows the hardware structural example which implement | achieves the detection part which concerns on one Embodiment of this invention. It is an external view which shows an example of the detection apparatus which concerns on one Embodiment of this invention. It is a functional block diagram which shows an example of functional structures, such as a detection part which concerns on one Embodiment of this invention. It is a block diagram which shows an example of the hardware constitutions of the control part which concerns on one Embodiment of this invention. It is a block diagram which shows an example of the hardware constitutions of the data management apparatus which the control part which concerns on one Embodiment of this invention has. It is a block diagram which shows an example of the hardware constitutions of the image output apparatus which the control part which concerns on one Embodiment of this invention has. It is a block diagram which shows an example of the correlation calculation method which concerns on one Embodiment of this invention. It is a figure which shows an example of the search method of the peak position in the correlation calculation which concerns on one Embodiment of this invention. It is a figure which shows the example of a calculation result of the correlation calculation which concerns on one Embodiment of this invention. It is a flowchart which shows the example of the whole process which concerns on one Embodiment of this invention. It is a figure which shows the example of a process result by the whole process which concerns on one Embodiment of this invention. It is a schematic diagram which shows the example of a setting of the detection range which concerns on one Embodiment of this invention. It is a timing chart and a conceptual diagram showing an example of detection by a sensor concerning one embodiment of the present invention. It is a functional block diagram which shows the function structural example of the apparatus which discharges the liquid which concerns on one Embodiment of this invention. It is a figure which shows the example from which the position of a recording medium fluctuates in an orthogonal direction. It is a figure which shows an example of the cause which color misregistration arises. It is the schematic which shows the example of whole structure of the apparatus which concerns on a comparative example. It is a figure which shows an example of the shift | offset | difference of the landing position in the apparatus which concerns on a comparative example. It is a figure which shows an example of the influence which eccentricity etc. of a roller have on the shift | offset | difference of a landing position. It is a figure which shows the example of a process result by the whole process which concerns on a comparative example. It is a figure which shows an example of the position where the sensor in the apparatus which discharges the liquid which concerns on one Embodiment of this invention is installed. It is a schematic diagram which shows the example of arrangement | positioning of the sensor in the apparatus which discharges the liquid which concerns on one Embodiment of this invention. It is a block diagram which shows an example of the moving mechanism for moving the liquid discharge head unit which the apparatus which discharges the liquid which concerns on one Embodiment of this invention has. It is the schematic which shows the modification of the apparatus which discharges the liquid which concerns on one Embodiment of this invention.

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

<Example of overall configuration>
Hereinafter, a case where the head unit included in the transport apparatus is a liquid discharge head unit that discharges liquid will be described as an example.

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

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

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

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

  Each liquid discharge head unit performs a process of discharging each liquid of each color on the web 120 conveyed in the conveyance direction 10. The web 120 is transported by two pairs of nip rollers, a roller 230, and the like. Hereinafter, of the two pairs of nip rollers, the nip roller installed on the upstream side of each liquid ejection head unit is referred to as a “first nip roller NR1”. On the other hand, a nip roller installed on the downstream side of the first nip roller NR1 and each liquid discharge head unit is referred to as a “second nip roller NR2”. Each nip roller rotates with a conveyed object such as the web 120 interposed therebetween, as shown in the figure. Thus, each nip roller and roller 230 is a mechanism or the like that conveys the web 120 and the like in a predetermined direction.

  The recording medium of the web 120 is preferably long. Specifically, the length of the recording medium is preferably longer than the distance between the first nip roller NR1 and the second nip roller NR2. Furthermore, the recording medium is not limited to the web. That is, the recording medium may be a sheet that is folded and stored, so-called “Z paper” or the like.

  Hereinafter, in the illustrated overall configuration example, each liquid discharge head unit is installed in the order of black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side toward the downstream side. To do. That is, the liquid discharge head unit installed on the most upstream side (hereinafter referred to as “black liquid discharge head unit 210K”) is used for black (K). A liquid discharge head unit (hereinafter referred to as “cyan liquid discharge head unit 210C”) installed next to the black liquid discharge head unit 210K is used for cyan (C). Further, a liquid discharge head unit (hereinafter referred to as “magenta liquid discharge head unit 210M”) installed next to the cyan liquid discharge head unit 210C is used for magenta (M). Subsequently, the liquid discharge head unit (hereinafter referred to as “yellow liquid discharge head unit 210Y”) installed on the most downstream side is used for yellow (Y).

  Each liquid discharge head unit discharges each color ink to a predetermined portion of the web 120 based on image data or the like. The position where the ejected ink lands on the web 120 (hereinafter referred to as “landing position”) is almost directly below the liquid ejection head unit. Hereinafter, an example in which the processing position where the processing is performed by the liquid discharge head unit is the landing position will be described.

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

  Specifically, each timing at which each liquid ejection head unit ejects ink is controlled by, for example, the controller 520 connected to each liquid ejection head unit.

  In addition, it is desirable that a plurality of rollers be installed for each liquid discharge head unit. Specifically, as illustrated, the plurality of rollers are installed, for example, on the upstream side and the downstream side, with each liquid discharge head unit interposed therebetween. In the illustrated example, for each liquid discharge head unit, a roller (hereinafter referred to as a “first roller”) used to convey the web 120 to each landing position is installed on the upstream side of each liquid discharge head unit. The In addition, rollers (hereinafter referred to as “second rollers”) used to convey the web 120 downstream from each landing position are installed on the downstream side of each liquid discharge head unit.

  In this way, when the first roller and the second roller are installed, so-called “flapping” is reduced at each landing position. The first roller and the second roller are used to transport the recording medium, and are, for example, driven rollers. Further, the first roller and the second roller may be rollers that are rotationally driven by a motor or the like.

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

  Specifically, a black first roller CR1K used for transporting the web 120 to the black landing position PK is installed at a predetermined portion of the web 120 in order to land black ink with high accuracy. On the other hand, a second black roller CR2K used for transporting the web 120 downstream from the black landing position PK is installed.

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

  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. 3A is a schematic plan view illustrating an example of four liquid discharge head units 210K to 210Y included in the image forming apparatus 110. As illustrated in FIG.

  As shown in FIG. 3A, each liquid discharge head unit is a line-type head unit in this example. In other words, the image forming apparatus 110 includes four liquid ejection head units 210K, 210C, 210M corresponding to black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side in the transport direction 10; 210Y is arranged.

  In this example, the black (K) liquid discharge head unit 210K has four heads 210K-1, 210K-2, 210K-3, and 210K-4 arranged in a staggered manner in the orthogonal direction. Thereby, the image forming apparatus 110 can form an image in the entire region in the width direction (orthogonal direction) in the region (print region) where the image is formed on the web 120. The configurations of the other liquid discharge head units 210C, 210M, and 210Y are the same as the configuration of the black (K) liquid discharge head unit 210K, and thus the description thereof is omitted.

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

<Example of detection unit>
For example, as illustrated in FIG. 2, the image forming apparatus 110 includes a sensor serving as an example of a detection unit for each liquid ejection head unit. In addition to the illustrated sensor, the image forming apparatus 110 may further include a sensor. For example, a sensor may further be provided upstream of the illustrated sensor. Hereinafter, the image forming apparatus 110 includes four sensors as illustrated. The sensor is not limited to being installed at the illustrated configuration and illustrated position.

  In the following description, a device such as a detection device installed for the black liquid discharge head unit 210K is referred to as a “black sensor SENK”. Similarly, a device such as a detection device installed for the cyan liquid discharge head unit 210C is referred to as “cyan sensor SENC”. Further, a device such as a detection device installed for the magenta liquid ejection head unit 210M is referred to as a “magenta sensor SENM”. Furthermore, a device such as a detection device installed for the yellow liquid discharge head unit 210Y is referred to as a “yellow sensor SENY”. In the following description, the black sensor SENK, the cyan sensor SENC, the magenta sensor SENM, and the yellow sensor SENY may be simply referred to as “sensor”.

  In the following description, “position where the sensor is installed” refers to a position where detection or the like is performed. Therefore, it is not necessary to install all the devices such as the detection device at the “position where the sensor is installed”, and devices other than the sensor may be installed at other positions connected by a cable or the like. The black sensor SENK, the cyan sensor SENC, the magenta sensor SENM, and the yellow sensor SENY are examples of positions where the sensors are installed.

  As the sensor, an optical sensor using light such as infrared rays, a sensor using laser, air pressure, photoelectric, or ultrasonic waves, or the like is used. The optical sensor may be, for example, a CCD (Charge Coupled Device) camera or a CMOS (Complementary Metal Oxide Semiconductor) camera.

  Furthermore, the optical sensor is preferably a global shutter. With the global shutter, even if the moving speed is high, the optical sensor can reduce the so-called image shift that occurs due to the shift of the shutter release timing, as compared with a rolling shutter or the like. In addition, the sensor preferably has a configuration described below, for example. That is, the sensor for realizing the detection unit is, for example, a sensor that can detect the surface of the recording medium. The sensors may be the same type or different types. In the following description, all the sensors are of the same type. Moreover, a sensor is implement | achieved by the structure etc. which are demonstrated below, for example.

  FIG. 4 is a block diagram illustrating an example of a hardware configuration that implements a detection unit according to an embodiment of the present invention. For example, the detection unit is realized by hardware such as a detection device 50, a control device 52, a storage device 53, and an arithmetic device 54 as illustrated.

  First, the detection device 50 is, for example, the following device.

  FIG. 5 is an external view showing an example of a detection apparatus according to an embodiment of the present invention.

  The detection apparatus shown in the figure is configured to image a speckle pattern or the like that is formed when light is applied from a light source to an object to be conveyed such as a web. Specifically, the detection apparatus first has an optical system such as a semiconductor laser light source (LD) and a collimating optical system (CL). The detection apparatus includes a CMOS image sensor for capturing an image in which a speckle pattern or the like is captured, and a telecentric imaging optical system (OL) for condensing and forming the speckle pattern on the CMOS image sensor.

  In the example of the configuration shown in the figure, the CMOS image sensor captures an image showing a speckle pattern a plurality of times, for example, at each of time “TM1” and time “TM2”. Then, based on the image picked up at time “TM1” and the image picked up at time “TM2”, an arithmetic unit such as a field-programmable gate array (FPGA) circuit performs processing such as cross-correlation calculation. . Next, based on the movement of the correlation peak position calculated by the correlation calculation or the like, the detection device or the like outputs the amount of movement or the like that the conveyed object has moved from time “TM1” to time “TM2”. In the example shown in the figure, the size of the detection device is set to width W × depth D × height H of 15 × 60 × 32 [mm]. Details of the correlation calculation will be described later.

  The CMOS image sensor is an example of hardware that realizes an imaging unit, and the FPGA circuit is an example of an arithmetic device.

  Returning to FIG. 4, the control device 52 controls the detection device 50 and the like. Specifically, for example, the control device 52 outputs a trigger signal to the detection device 50 to control the timing at which the CMOS image sensor releases the shutter. In addition, the control device 52 performs control so that a two-dimensional image can be acquired from the detection device 50. Then, the control device 52 captures an image from the detection device 50 and sends the generated two-dimensional image to the storage device 53 and the like.

  The storage device 53 is a so-called memory or the like. It is desirable that the two-dimensional image sent from the control device 52 or the like can be divided and stored in different storage areas.

  The arithmetic device 54 is a microcomputer or the like. That is, the computing device 54 performs computations for realizing various processes using image data stored in the storage device 53.

  The control device 52 and the arithmetic device 54 are, for example, a CPU (Central Processing Unit) or an electronic circuit. Note that the control device 52, the storage device 53, and the arithmetic device 54 may not be different devices. For example, the control device 52 and the calculation device 54 may be one CPU or the like.

<Functional configuration example of detection unit etc.>
FIG. 6 is a functional block diagram illustrating an example of a functional configuration of a detection unit and the like according to an embodiment of the present invention. Hereinafter, as illustrated, a combination of a black liquid discharge head unit 210K and a cyan liquid discharge head unit 210C among detection units installed for each head unit will be described as an example.

  Further, as shown in the figure, the detection unit 52A for the black liquid ejection head unit 210K outputs the detection result related to the “A position”, and the detection unit 52B for the cyan liquid ejection head unit 210C detects the detection related to the “B position”. An example of outputting the result will be described. First, the detection unit 52A for the black liquid ejection head unit 210K includes, for example, an imaging unit 16A, an imaging control unit 14A, an image storage unit 15A, and the like. In this example, the detection unit 52B for the cyan liquid ejection head unit 210C has, for example, the same configuration as the detection unit 52A, and includes an imaging unit 16B, an imaging control unit 14B, an image storage unit 15B, and the like. Hereinafter, the detection unit 52A will be described as an example.

  The imaging unit 16A images the web 120 conveyed in the conveyance direction 10 as illustrated. Note that the imaging unit 16A is realized by, for example, the detection device 50 or the like (FIG. 4 or the like).

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

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

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

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

  The calculation unit 53F can calculate the position of the pattern that the web 120 has, the movement speed at which the web 120 is conveyed, and the movement amount at which the web 120 is conveyed based on the images stored in the image storage units 15A and 15B. . Further, the calculation unit 53F outputs data of the time difference Δt indicating the timing of releasing the shutter to the shutter control unit 141A. That is, the calculation unit 53F indicates to the shutter control unit 141A the timing to release the shutter so that the image indicating the “A position” and the image indicating the “B position” are respectively captured with a time difference Δt. Further, the calculation unit 53F may control a motor or the like that conveys the web 120 so that the calculated moving speed is achieved. Note that the calculation unit 53F is realized by, for example, the controller 520 or the like (FIG. 2).

  The web 120 is a member having scattering properties on the surface or inside thereof. Therefore, when the web 120 is irradiated with laser light, the reflected light is diffusely reflected. A pattern is formed on the web 120 by the diffuse reflection. That is, the pattern is a so-called speckle pattern called “speckle”. Therefore, when the web 120 is imaged, an image showing a speckle pattern is obtained. Since the position where the speckle pattern is present is known from this image, it is possible to detect where the predetermined position of the web 120 is. This speckle pattern is generated because the irradiated laser beam interferes with the uneven shape formed on the surface or inside of the web 120.

  Further, the light source is not limited to an apparatus using laser light. For example, the light source may be an LED (Light Emitting Diode) or an organic EL (Electro-Luminescence). The pattern may not be a speckle pattern depending on the type of light source. Hereinafter, an example in which the pattern is a speckle pattern will be described.

  Therefore, when the web 120 is conveyed, the speckle pattern of the web 120 is also conveyed. Therefore, when the same speckle pattern is detected at different times, the amount of movement in the transport direction is obtained. That is, when the same speckle pattern is detected and the movement amount of the pattern is obtained, the calculation unit 53F can obtain the movement amount of the web 120 in the conveyance direction. When the obtained movement amount is converted per unit time, the calculation unit 53F can obtain the movement speed at which the web 120 is conveyed in the conveyance direction.

  As shown in the figure, the imaging units are installed at a constant interval in the transport direction 10. Then, the web 120 is imaged at each position by each imaging unit.

Assuming that the time difference is Δt, the shutter control unit 141A causes the imaging unit 16A to image the web 120 at intervals of the time difference Δt. Based on the speckle pattern indicated by the image generated by the imaging, the calculation unit 53F obtains the movement amount of the web 120. Specifically, when the moving speed V [mm / s] and the relative distance L [mm] that is the interval at which the sensors are installed in the transport direction 10, the time difference Δt is expressed by the following equation (1). Can be shown.

Δt = L / V (1)

In the above equation (1), the relative distance L [mm] is an interval between the “A position” and the “B position” and can be obtained in advance. Therefore, when the time difference Δt is determined, the calculation unit 53F can obtain the moving speed V [mm / s] based on the above equation (1). As described above, based on the speckle pattern, the image forming apparatus can accurately obtain the position, the moving amount and the moving speed in the transport direction, or a combination thereof. Note that the image forming apparatus may output a combination of any of the position, movement amount, and movement speed in the transport direction.

  The sensor may detect the position in the orthogonal direction and the like. That is, the sensor may also be used to detect the respective positions in the transport direction and the orthogonal direction. If the sensor is also used in this way, the cost for installing the device in each direction can be reduced. In addition, since the number of sensors can be reduced, space can be saved.

  Furthermore, the calculation unit 53F performs a cross-correlation operation on the image data D1 (n) and D2 (n) captured by the detection units 52A and 52B. Hereinafter, an image generated by the cross correlation calculation is referred to as a “correlation image”. For example, the calculation unit 53F calculates the shift amount ΔD (n) based on the correlation image.

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

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

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

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

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

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

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

  In this way, the calculation unit 53F can calculate the shift amount ΔD (n) based on the correlation image even with a broad luminance distribution.

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

  Based on the timing calculated by such calculation, the black liquid discharge head unit 210K and the cyan liquid discharge head unit 210C each discharge liquid. The liquid discharge timing is controlled by the first signal SIG1 for the black liquid discharge head unit 210K and the second signal SIG2 for the cyan liquid discharge head unit 210C output from the control unit 110F30.

  Further, the position where the sensor is installed is preferably a position close to each landing position. If a sensor is installed at a position close to each landing position, the distance between each landing position and the sensor becomes short. And if the distance between each landing position and the sensor is shortened, errors in detection can be reduced. Therefore, the image forming apparatus can detect the position of the conveyed object with high accuracy by the sensor.

  Specifically, the position close to each landing position is, for example, between each first roller and each second roller, as shown in FIG. In other words, in the illustrated example, the position where the black sensor SENK is installed is desirably the inter-black roller INTK1 as illustrated. Similarly, the position where the cyan sensor SENC is installed is preferably between the cyan rollers INTC1, as shown. Further, the position where the magenta sensor SENM is installed is preferably the magenta roller INTM1 as shown. Furthermore, it is desirable that the position where the yellow sensor SENY is installed is the inter-yellow roller INTY 1 as illustrated.

  Thus, when a sensor is installed between the rollers, the sensor can detect the position of the recording medium at a position close to each landing position. In many cases, the moving speed is relatively stable between the rollers. Therefore, the image forming apparatus can accurately detect the position of the conveyed object.

  Furthermore, the position where the sensor is installed is preferably a position closer to the first roller than the landing position between the rollers. That is, the position where the sensor is installed is desirably upstream of each landing position.

  Specifically, the position where the black sensor SENK is installed is from the black landing position PK to the position where the first black roller CR1K is installed upstream (hereinafter referred to as “black upstream section INTK2”). .) Is desirable. Similarly, the position where the cyan sensor SENC is installed is from the cyan landing position PC to the position where the first cyan roller CR1C is installed upstream (hereinafter referred to as “cyan upstream section INTC2”). It is desirable that Further, the position where the magenta sensor SENM is installed is from the magenta landing position PM to the position where the first magenta roller CR1M is installed upstream (hereinafter referred to as “magenta upstream section INTM2”). It is desirable. Furthermore, the position where the yellow sensor SENY is installed is from the yellow landing position PY to the position where the first yellow roller CR1Y is installed toward the upstream side (hereinafter referred to as “yellow upstream section INTY2”). It is desirable that

  When sensors are installed in the black upstream section INTK2, the cyan upstream section INTC2, the magenta upstream section INTM2, and the yellow upstream section INTY2, the image forming apparatus can accurately detect the position of the conveyed object.

  When the sensor is installed at such a position, the sensor is installed upstream from each landing position. Therefore, first, the image forming apparatus can accurately detect the position of the recording medium in the orthogonal direction, the transport direction, or both directions by the sensor on the upstream side. Therefore, the image forming apparatus can calculate the timing at which each liquid ejection head unit ejects liquid, the amount of movement of the head unit, or both. That is, when the web 120 is conveyed to the landing position after the position is detected on the upstream side, the timing is calculated or the head unit is moved during that time, so the image forming apparatus changes the landing position with high accuracy. be able to.

  If the position immediately below each liquid discharge head unit is the position where the sensor is installed, color misregistration may occur due to a delay for the control operation. Therefore, when the position where the sensor is installed is upstream from each landing position, the image forming apparatus can reduce color misregistration and improve image quality. In addition, there are cases where the vicinity of each landing position or the like is set as a position where a sensor or the like is installed. Therefore, the position where the sensor is installed is desirably closer to each first roller than each landing position.

  Further, the position of the sensor may be, for example, directly below each liquid discharge head unit. In the following description, an example in which the sensor is directly below each liquid discharge head unit will be described. As in this example, when the sensor is directly below, the accurate movement amount immediately below can be detected by the sensor. Therefore, if the control operation or the like can be performed quickly, it is desirable that the sensor is located closer to the position immediately below each liquid discharge head unit. On the other hand, the sensor does not have to be directly under each liquid discharge head unit, and the same calculation is performed even when the sensor is not directly under.

  If the error is acceptable, the position of the sensor is directly below each liquid discharge head unit or between each first roller and each second roller, and downstream of each liquid discharge head unit. Or the like.

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

  FIG. 7 is a block diagram illustrating an example of a hardware configuration of a control unit according to an embodiment of the present invention. For example, the controller 520 includes a host device 71 that is an information processing device and the like, and a printer device 72. In the illustrated example, the controller 520 causes the printer device 72 to form an image on the recording medium based on the image data and control data input from the host device 71.

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

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

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

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

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

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

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

  FIG. 8 is a block diagram illustrating an example of a hardware configuration of a data management apparatus included in the control unit according to the embodiment of the present invention. For example, the plurality of data management devices have the same configuration. Hereinafter, an example in which each data management device has the same configuration will be described, and the data management device 72EC will be described as an example. Therefore, the overlapping description is omitted.

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

  The logic circuit 72ECl stores the image data input from the host device 71 in the storage device 72ECm based on the control signal input from the printer controller 72C (FIG. 7).

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

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

  FIG. 9 is a block diagram illustrating an example of a hardware configuration of the image output apparatus 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 that are liquid discharge head units for each color. Control unit 210Y.

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

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

  The printer device 72 is an example in which a route for inputting image data from the host device 71 and a route used for transmission / reception between the host device 71 and the printer device 72 based on the control data are different from each other.

  The printer device 72 may be configured to form an image with one black color, for example. In order to increase the speed of image formation when performing image formation with one black color, for example, a configuration including one data management device and four black liquid discharge head units may be used. In this way, black ink is ejected by each of the plurality of black liquid ejection head units. Therefore, it is possible to perform faster image formation as compared with a configuration in which one black liquid discharge head unit is used.

  The conveyance control device 72Ec is a motor or the like that conveys the web 120. For example, the conveyance control device 72Ec controls a motor or the like connected to each roller or the like to convey the web 120.

<Example of correlation calculation>
Further, the correlation calculation may be calculated as follows, for example.

  FIG. 10 is a configuration diagram illustrating an example of a correlation calculation method according to an embodiment of the present invention. For example, the detection unit can output a detection result indicating the relative position of the web, the movement amount, the movement speed, or a combination of these at the position of the sensor when performing the correlation calculation with the configuration shown in the figure.

  Specifically, as illustrated, the detection unit 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 a calculation unit CAL. And a conversion result storage unit MEM.

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

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

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

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

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

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

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

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

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

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

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

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

  FIG. 11 is a diagram illustrating an example of a peak position search method in correlation calculation according to an embodiment of the present invention. In the figure, the horizontal axis indicates the position in the transport direction in the image indicated by the correlation image data. On the other hand, the vertical axis indicates the luminance of the image indicated by the correlation image data.

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

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

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

  FIG. 12 is a diagram illustrating a calculation result example of the correlation calculation according to the embodiment of the present invention. The figure shows the correlation strength distribution of the cross-correlation function. In the figure, the X axis and the Y axis indicate pixel serial numbers. A peak position such as a “correlation peak” shown in the figure is searched by the peak position search unit SR.

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

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

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

  First, a detection part binarizes each brightness | luminance of 1st image data and 2nd image data. That is, the detection unit sets “0” if the luminance is equal to or lower than a preset threshold value, and sets “1” if the luminance is larger than the threshold value. The detection unit may detect the relative position by comparing the binarized first image data and second image data.

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

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

<Example of overall processing>
FIG. 13 is a flowchart showing an example of overall processing according to an embodiment of the present invention. For example, the image forming apparatus performs the following overall processing.

  In step S10, the image forming apparatus detects the position of the web 120 by a sensor. In step S10, the image forming apparatus may further detect a moving speed or the like. Step S10 may be performed during image formation.

  In step S11, the image forming apparatus calculates a statistical value of the position. For example, after a plurality of positions can be detected in step S10, in step S11, the image forming apparatus performs statistical processing on the plurality of positions and calculates a statistical value such as an average value.

  The statistical value is not limited to the average value. For example, the statistical value may be a median value or a moving average value. Specifically, the image forming apparatus calculates a moving average value by statistical processing that averages a predetermined number of positions detected most recently. In addition, the image forming apparatus calculates the median value by statistical processing for extracting the median value from the detected plurality of positions. Hereinafter, an example in which the statistical value is an average value will be described.

  In addition, in step S11, the image forming apparatus calculates a statistical value such as a standard deviation σ and an integral multiple of the standard deviation σ (for example, 3σ or 6σ) after detecting a plurality of positions. May be. Further, in step S11, the image forming apparatus may calculate a statistical value by extracting a maximum value and a minimum value from a plurality of positions.

  In step S12, the image forming apparatus sets a detection range based on the statistical value. Details of the detection range setting will be described later.

  In step S13, the image forming apparatus performs processing such as image formation. Then, the image forming apparatus obtains a detection result indicating the position and the like of the web 120 from the sensor within the detection range set in step S12 during the image forming process. Further, the image forming apparatus adjusts the timing for ejecting the liquid, moves the liquid ejection head unit in the orthogonal direction, or a combination thereof during processing such as image formation.

<Example of overall processing results>
FIG. 14 is a diagram showing a processing result example by the overall processing according to the embodiment of the present invention. Hereinafter, a case where detection results of two types of webs 120 are obtained will be described as an example. Specifically, it is assumed that one type of web 120 is a transported object that fluctuates as indicated by the detection result POS1. Similarly, it is assumed that the other type of web 120 is a transported object that fluctuates as indicated by the detection result POS2.

  That is, each data constituting the detection result POS1 and the detection result POS2 shown in the figure is the detection result obtained in step S10. For example, when the web 120 expands and contracts, or when the roller 230 (FIG. 2) that conveys the web 120 thermally expands, fluctuations as illustrated are likely to occur. Specifically, the web 120 expands and contracts by about 400 μm (micrometer) to 500 μm. The amount of expansion / contraction varies depending on the type of the object to be conveyed.

  In the illustrated example, the detection result POS1 varies more than the detection result POS2. That is, the web 120 detected by the detection result POS1 is more easily expanded and contracted than the detection result POS2.

  In the illustrated example, a range in which the sensor can detect a position and the like is referred to as “detection range RA”. As shown in the drawing, even if the position of the web 120 varies, the sensor can detect the position of the web 120 and the like as long as the position is within the detection range RA.

  Hereinafter, the detection result POS1 will be described using an example in which the entire process illustrated in FIG. 13 is performed.

  First, when statistical processing is performed on the detection result POS1, the image forming apparatus can calculate an average value PAVE (step S11). In the illustrated example, the image forming apparatus sets the center of the detection range RA in accordance with the average value PAVE (step S12). In this way, as shown in the figure, the image forming apparatus can output the detection result within the detection range RA even if there is a variation due to thermal expansion or the like. In particular, the image forming apparatus can detect the position and the like of the web 120 without deviating from the detection range RA even if the object to be conveyed is the easily-extensible web 120 like the detection result POS1.

  In the example shown in the figure, the calculation and setting of the statistical value are performed for each cycle in which the detection result POS1 varies (hereinafter referred to as “variation cycle CYC”). For example, the fluctuation cycle CYC is a cycle of tension generated in the web 120. Specifically, the variation period CYC is, for example, a period synchronized with the rotation period of the roller 230 in the example illustrated in FIG. Note that the calculation and setting of statistical values need not always be performed in each cycle, and may be performed every several cycles, for example.

  Further, it is desirable that the image forming apparatus calculates a statistical value such as a maximum value MAX, a minimum value MIN, a standard deviation σ, an integral multiple of the standard deviation σ, or a combination thereof. The detection range is set as follows based on the statistical value, for example.

<Setting example of detection range>
FIG. 15 is a schematic diagram illustrating a setting example of a detection range according to an embodiment of the present invention. For example, in step S12, the image forming apparatus sets the detection range as follows.

  First, in the illustrated example, as shown in FIG. 15A, it is assumed that the black sensor SENK can detect the maximum black detection range SEK. For example, it is assumed that the black sensor SENK is set to detect the black initial detection range SRK1 in the initial state.

  Similarly, the cyan sensor SENC is set to detect the cyan initial detection range SRC1 in the initial state in the cyan detectable range SEC. Further, it is assumed that the magenta sensor SENM is set to detect the magenta initial detection range SRM1 in the initial state in the magenta detectable range SEM. Furthermore, it is assumed that the yellow sensor SENY is set to detect the yellow initial detection range SRY1 in the initial state in the yellow detectable range SEY.

  Next, in step S12, the image forming apparatus sets a detection range, for example, as shown in FIG. In the illustrated example, the second detection range for black SRK2, the second detection range for cyan SRC2, the second detection range for magenta SRM2, and the second detection range for yellow SRY2 are set. If it does in this way, each detection range will become a downstream rather than the case shown to FIG. 15 (A). Therefore, even if the web 120 expands and contracts in the transport direction 10, the image forming apparatus can detect the position of the web 120 with high accuracy.

  The setting is not limited to moving the detection range in the transport direction 10. For example, the image forming apparatus may set the detection range like a third black detection range SRK3 illustrated in FIG. Specifically, the third black detection range SRK3 is an example in which the detection range is set wider in the transport direction 10 than the second black detection range SRK2. As described above, the image forming apparatus may perform setting for enlarging or reducing the detection range.

  For example, the image forming apparatus first calculates the amplitude due to expansion and contraction of the conveyed object. If the fluctuation is large, for example, if the amplitude is 0.75 times or more the width of the detection range in which the amplitude is set, the image forming apparatus expands the width of the detection range to 1.25 times. On the other hand, when the fluctuation is small, for example, when the amplitude is 0.25 times or less the width of the detection range in which the amplitude is set, the image forming apparatus reduces the width of the detection range to 0.75 times. Note that other values may be used for the threshold, the enlargement magnification, and the reduction magnification.

  In this way, the image forming apparatus can set a detection range that is neither too wide nor too narrow.

  In addition, for example, the setting may be performed in the orthogonal direction 20. For example, the image forming apparatus may set the detection range like a fourth black detection range SRK4 shown in FIG. Specifically, the image forming apparatus is an example in which the third black detection range SRK3 is moved in the orthogonal direction 20. The image forming apparatus may set the detection range in the orthogonal direction 20 like the black fourth detection range SRK4 shown in the drawing. Further, as in FIG. 15C, the image forming apparatus may perform setting for enlarging or reducing the detection range in the orthogonal direction 20.

  In the illustrated example, the detection range of each color is set in the same manner. However, the setting may be different based on the detection result of the sensor corresponding to each color. That is, the detection ranges may be the same or different.

  Then, for example, as shown in FIG. 15C, the image forming apparatus shows an example of 3σ that is an integral multiple of the maximum value MAX, the minimum value MIN, or the standard deviation σ (in the figure, three times the standard deviation σ). It is desirable to make settings such as enlargement, reduction, or movement of the detection range so that.

  As described above, the image forming apparatus detects, for example, as follows according to the set detection range.

<Detection example>
FIG. 16 is a timing chart and a conceptual diagram showing an example of detection by a sensor according to an embodiment of the present invention.

  In the illustrated example, the first timing T1 is a timing at which black liquid is discharged, and the second timing T2 is a timing at which cyan liquid is discharged. In this example, the detection timing at which the cyan sensor SENC installed between the black liquid discharge head unit 210K and the cyan liquid discharge head unit 210C performs detection is defined as a third timing T3.

  In this example, the position where the cyan sensor SENC detects is hereinafter referred to as “detection position PSEN”. As shown in the figure, the detection position PSEN is assumed to be a position “installation distance D” from the landing position of the cyan liquid ejection head unit 210C. In the following example, it is assumed that the interval at which each sensor is installed is the same as the installation interval (relative distance L) of each liquid ejection head unit.

  First, at the first timing T1, the image forming apparatus turns on the first signal SIG1 so as to cause the black liquid ejection head unit 210K to eject liquid. Then, the image forming apparatus acquires image data at a detection timing at which the first signal SIG1 is “ON”. In the illustrated example, the image acquired at the first timing T1 is indicated by the first image signal PA, and the image data corresponds to the image data D1 (n) at “position A” shown in FIG.

  When the image data D1 is acquired, the image forming apparatus can detect the position of a predetermined location, the moving speed V at which the web 120 is conveyed, and the like. If the moving speed can be detected, the image forming apparatus divides the relative distance L by the moving speed V (L ÷ V), and calculates the time required for a predetermined location to be conveyed to the next landing position. Can be calculated.

  Next, at the third timing T3, the image forming apparatus acquires image data. In the illustrated example, the image acquired at the third timing T3 is indicated by the second image signal PB, and the image data corresponds to the image data D2 (n) at the “B position” shown in FIG. Next, the image forming apparatus performs a cross-correlation operation on the image data D1 (n) and D2 (n). In this way, the image forming apparatus can calculate the shift amount ΔD (0).

  In a state where there is no thermal expansion of the roller and no slip between the roller and the web 120, that is, in a so-called ideal state, the image forming apparatus moves a relative distance L in a predetermined portion of the web 120. It takes time “L ÷ V” to transport at the speed V.

  Accordingly, the “imaging cycle T” illustrated in FIG. 10 is set to, for example, “imaging cycle T = imaging time difference = relative distance L / movement speed V”. In the example shown in the drawing, the black sensor SENK and the cyan sensor SENC are installed at an interval of a relative distance L. If it is in the ideal state, the predetermined portion of the web 120 detected by the black sensor SENK is conveyed to the detection position PSEN after “L ÷ V” time.

  On the other hand, actually, in many cases, thermal expansion occurs in the roller or slip occurs between the roller and the web 120. In the correlation calculation method shown in FIG. 10, when “imaging cycle T = relative distance L / moving speed V” is set, the timing at which image data D1 (n) is imaged by the black sensor SENK, and the cyan sensor SENC Thus, the time difference from the timing at which the image data D2 (n) is imaged is “L ÷ V”. In this way, the image forming apparatus may calculate the deviation amount ΔD (0) by setting “L ÷ V” as “imaging cycle T”. Hereinafter, an example of the third timing illustrated will be described.

  At the third timing T3, the image forming apparatus calculates a deviation amount ΔD (0), which is an example of the second distance. Then, the image forming apparatus changes the timing at which the cyan liquid ejection head unit 210C ejects the liquid, that is, the second timing T2, based on the installation distance D, the shift amount ΔD (0), and the moving speed V.

  In an ideal state where the roller has no thermal expansion, the image forming apparatus takes time “D ÷ V” to convey the installation distance D at the moving speed V. Therefore, the time “D ÷ V” is calculated based on “L ÷ V”, and the second timing T2 is determined. On the other hand, in reality, the position where the liquid is to be discharged is at a position of a deviation amount ΔD (0) from the position where the cyan liquid discharge head unit 210C discharges the liquid due to thermal expansion of the roller. Therefore, it takes time of “ΔD (0) ÷ V” for the predetermined portion to be transported to the position where the cyan liquid discharge head unit 210C discharges the liquid. Therefore, the image forming apparatus changes the timing so that the liquid can be discharged at the position where the deviation amount ΔD (0) is obtained.

  Specifically, the timing change amount is “(ΔD (0) −D) / V”. In this way, the image forming apparatus changes the second timing T2 to be shifted by “(ΔD (0) −D) / V”. In this way, even if the roller has thermal expansion or the like, the image forming apparatus changes the timing based on the shift amount ΔD (0), the installation distance D, and the moving speed V. The accuracy of the landing position can be improved.

  In addition, the ideal moving speed may be set in advance for each mode in the image forming apparatus. The ideal moving speed is a moving speed in a state where there is no thermal expansion or the like.

  Although the example in which the timing is changed is described above, the image forming apparatus directly calculates and determines the timing at which the liquid ejection head unit ejects the liquid based on the deviation amounts, “V” and “D”. You may do it.

<Functional configuration example>
FIG. 17 is a functional block diagram illustrating a functional configuration example of an apparatus for ejecting liquid according to an embodiment of the present invention. For example, the image forming apparatus 110 has a functional configuration including a detection unit 110F10 for each head unit as illustrated. Further, as illustrated, the image forming apparatus 110 includes a setting unit 110F40 and a statistical value calculation unit 110F50. The image forming apparatus 110 preferably has a functional configuration further including a measurement unit 110F20 and a control unit 110F30 as illustrated.

  As shown in the figure, the detection unit 110F10 is installed for each liquid ejection head unit. Specifically, in the example illustrated in FIG. 2, the number of detection units 110F10 is four as illustrated. In addition, the detection unit 110F10 performs a detection procedure for outputting a detection result indicating the position, moving speed, moving amount, or a combination thereof of the web 120. In this manner, the image forming apparatus 110 can output a detection result indicating the position, moving speed, moving amount, or combination thereof of the object to be conveyed during processing by the detection unit 110F10.

  The detection unit 110F10 is realized by, for example, the hardware configuration illustrated in FIG. Further, the detection unit 110F10 corresponds to the detection units 52A and 52B in FIG.

  The statistical value calculation unit 110F50 performs a statistical value calculation procedure for calculating a statistical value of the position of the web 120 based on a plurality of detection results. For example, the statistical value calculation unit 110F50 is realized by the controller 520 (FIG. 2) or the like.

  The setting unit 110F40 performs a setting procedure for setting a detection range in which the detection unit 110F10 performs detection based on the statistical value calculated by the statistical value calculation unit 110F50. For example, the setting unit 110F40 is realized by the controller 520 (FIG. 2) or the like.

  The controller 110F30 causes each of the plurality of liquid ejection head units to eject liquid at a timing determined based on the detection result by the detection unit 110F10. The control unit 110F30 is realized by, for example, the hardware configuration illustrated in FIG.

  Further, when the measurement unit 110F20 is provided, the image forming apparatus 110 can detect the position of the recording medium and the like more reliably. For example, it is assumed that a measuring device such as an encoder is installed on the rotating shaft of the roller 230. Then, the measurement unit 110F20 measures the amount of movement of the recording medium using an encoder or the like. As described above, when the measurement result measured by the measurement unit 110F20 is further input, the image forming apparatus 110 can more reliably detect the position of the recording medium in the transport direction.

  With the configuration as described above, the image forming apparatus 110 uses the setting unit 110F40 to set the detection range set as the black initial detection range SRK1 in the initial state as the black second detection range SRK2, the black third detection range, for example. The detection range SRK3 or the fourth detection range SRK4 for black can be set.

  For example, as shown in FIG. 14, the web 120 may fluctuate. Therefore, the image forming apparatus 110 performs statistical processing on the plurality of positions detected by the setting unit 110F40 by the statistical value calculation unit 110F50 and calculates a statistical value. In this way, the image forming apparatus 110 can calculate a statistical value such as an average value, a median value, a moving average value, a maximum value MAX, a minimum value MIN, a standard deviation σ, an integer multiple of the standard deviation σ, or a combination thereof. .

  Then, the image forming apparatus 110 sets the detection range so that the statistical value is included by the setting unit 110F40. If the detection range is too wide, unnecessary detection is likely to be performed, and wasteful processing is likely to occur. On the other hand, if the detection range is too narrow, the position may be outside the detection range when the transfer target fluctuates due to expansion / contraction of the transfer target, “meandering”, thermal expansion of the roller 230, or a combination thereof. There is. “Meandering” is, for example, the following phenomenon.

  FIG. 18 is a diagram illustrating an example in which the position of the recording medium varies in the orthogonal direction. Hereinafter, an example in which the web 120 is conveyed in the conveyance direction 10 as illustrated in FIG. As shown in this example, the web 120 is conveyed by a roller or the like. Thus, when the web 120 is conveyed, the position of the web 120 may fluctuate in the orthogonal direction as shown in FIG. 18B, for example. That is, the web 120 may “meander” as shown.

  In the example shown in the figure, the rollers are arranged obliquely. In the figure, the state of being “oblique” is described in an easy-to-understand manner, and the inclination of the roller or the like may be less than in the illustrated example.

  The variation in the position of the web 120 in the orthogonal direction, that is, “meandering” occurs due to, for example, eccentricity of a roller related to conveyance, misalignment, or cutting of the web 120 by a blade. In addition, when the web 120 is narrow in the orthogonal direction, the thermal expansion of the roller may affect the variation in the position of the web 120 in the orthogonal direction.

  For example, when vibrations occur due to roller eccentricity or blade cutting, the web 120 may “meander” as shown. In addition, the blade 120 may not be evenly cut, and the web 120 may “meander” as illustrated depending on the physical characteristics of the web 120, that is, the shape after the web 120 is cut. is there.

  FIG. 19 is a diagram illustrating an example of a cause of color misregistration. As described with reference to FIG. 18, when the position of the recording medium fluctuates in the orthogonal direction, that is, “meandering” occurs, the following color misregistration is likely to occur.

  Specifically, when an image is formed on a recording medium using a plurality of colors, that is, when a color image is formed, the image forming apparatus discharges each liquid discharge head unit as illustrated. A color image by a so-called color plane is formed on the web 120 by superimposing the inks of the respective colors.

  On the other hand, there is a position variation as described in FIG. For example, “meandering” may occur based on the reference line 320. In this case, when each liquid discharge head unit discharges ink to the same position, the position of the web 120 fluctuates in the orthogonal direction due to “meandering” between the liquid discharge head units. May occur. In other words, the color misalignment 330 occurs when the position of a line or the like formed by the ink ejected by each liquid ejection head unit deviates in the orthogonal direction. As described above, when the color misregistration 330 occurs, the image quality of the image formed on the web 120 may deteriorate.

  If there is such “meandering” as described above, the position of the conveyed object may be affected and fluctuate.

  Therefore, the image forming apparatus 110 sets a detection range by the setting unit 110F40, for example, as shown in FIG. In this way, the image forming apparatus 110 can detect the position of the conveyed object in a detection range that is not too wide and not too narrow even if the position of the conveyed object varies.

  Note that the image forming apparatus 110 may change the detection range when there is a change greater than or equal to a predetermined value compared to a predetermined value set in advance. For example, the position of the conveyed object may change temporarily due to disturbance. Therefore, for example, when the average value changes to a predetermined value or more, the image forming apparatus 110 changes the detection range. On the other hand, if the change in the average value is less than the predetermined value, the image forming apparatus 110 maintains the detection range. In some cases, the image forming apparatus 110 can detect the position and the like more accurately when the detection range is set more stably than when the detection range is changed many times in a short time.

  Therefore, when the predetermined value is set in advance and there is a change greater than or equal to the predetermined value, if the detection range is changed, the image forming apparatus 110 can use a stable detection range.

  Note that the statistical value is preferably calculated based on a long distance. For example, in the configuration shown in FIG. 2, the statistical value is preferably calculated based on the interval between the position where the black sensor SENK detects and the position where the yellow sensor SENY detects. That is, the detection result POS1 and the like shown in FIG. 14 are desirably values obtained by detecting the interval between the position where the black sensor SENK detects and the position where the yellow sensor SENY detects. When such a long distance is used, the interval between the “A position” and the “B position” shown in FIG. 6 can be increased. As described above, when a long distance is used, the image forming apparatus 110 can calculate the statistical value with high accuracy.

  In addition, the apparatus for ejecting liquid according to the embodiment obtains a detection result such as a position, a moving speed, or a moving amount in the transport direction, the orthogonal direction, or both directions for each liquid discharge head unit.

  Therefore, the apparatus for ejecting liquid according to the embodiment can determine the timing of ejecting liquid for each liquid ejection head unit based on the detection result and the like. Therefore, as compared with the above-described comparative example or the like, the apparatus for ejecting liquid according to the embodiment can accurately compensate for the deviation generated at the liquid landing position in the transport direction.

  Further, in the apparatus for ejecting liquid according to the embodiment, each liquid ejection head unit is less required to be disposed at a position obtained by multiplying the circumferential length of the roller by an integral number as compared with the comparative example described above. There are fewer restrictions on the installation.

  Further, in the apparatus for ejecting liquid according to the embodiment, the movement amount is not calculated based on the rotation amount of the roller as in the above comparative example, but the position of the web can be directly detected. Effects such as expansion can be canceled with high accuracy. In addition, in the apparatus for ejecting liquid according to an embodiment of the present invention, if detection is performed at a position close to the liquid ejection head unit, the influence of web expansion and contraction can be canceled with high accuracy.

  Thus, when the influence of roller eccentricity, roller thermal expansion, slip generated between the web and the roller, expansion / contraction of the recording medium, and combinations thereof can be reduced, the device for discharging liquid is discharged. The accuracy of the liquid landing position can be further improved.

  In addition, when an image is formed on a recording medium by ejecting a liquid, the apparatus for ejecting the liquid according to the embodiment reduces the color misregistration when the landing positions of the ejected liquids of the respective colors are improved. The quality of the image to be displayed can be improved.

  Further, each detection unit detects the position, moving speed, amount of movement, or a combination of these for each liquid discharge head unit based on the patterns of the conveyed object at two or more different timings. . In this way, since the timing at which each liquid ejection head unit ejects the liquid is controlled based on the respective detection results, the device that ejects the liquid can more accurately shift the liquid landing position. Can compensate.

<Comparative example>
FIG. 20 is a schematic diagram illustrating an overall configuration example of an apparatus according to a comparative example. The illustrated image forming apparatus 110A is different in that the sensor is not installed, that is, the detection unit is not provided. In this comparative example, the roller 220 and the roller 230 convey the web 120. Note that the encoder ENC is installed with respect to the rotation shaft of the roller 230.

  In the image forming apparatus 110A, each liquid discharge head unit is arranged at a position obtained by multiplying the circumferential length of the roller 230 by an integer. In this way, the deviation due to the eccentricity of the roller synchronized with the rotation period of the roller is cancelled. Further, the displacement of the position where each liquid discharge head unit is installed may be canceled by correcting the timing at which each liquid discharge head unit discharges the liquid by a test print or the like.

  In the image forming apparatus 110A, each liquid discharge head unit discharges liquid based on the encoder pulse output from the encoder ENC.

  FIG. 21 is a diagram illustrating an example of a landing position shift in the apparatus according to the comparative example. FIG. 10 shows an example of the deviation of the position where the liquid ejected from each liquid ejection head unit has landed in the image forming apparatus 110A shown in FIG.

  The first graph G1 shows the actual web position. On the other hand, the second graph G2 is the position of the web calculated based on the encoder pulse from the encoder ENC. That is, if there is a difference between the first graph G1 and the second graph G2, the actual web position in the transport direction is different from the calculated web position, so that the landing position is likely to be misaligned. .

  For example, in the liquid discharge by the black liquid discharge head unit 210K, a deviation amount ΔK is generated. Further, the amount of deviation may be different for each liquid ejection head unit. That is, in the ejection other than black, each misalignment amount is often different from the misalignment amount ΔK.

  The amount of misalignment is caused by, for example, roller eccentricity, thermal expansion of the roller, slip generated between the web and the roller, expansion / contraction of the recording medium, and combinations thereof.

  FIG. 22 is a diagram illustrating an example of the influence of the eccentricity of the roller or the like on the deviation of the landing position. The illustrated graph shows an example of the influence of slippage between the roller and the web, thermal expansion and eccentricity of the roller, and the like. That is, each graph shows the difference between the web position calculated based on the encoder signal from the encoder ENC and the actual position by the “deviation amount” on the vertical axis. The illustrated example shows an example in which the roller has an outer diameter of “φ60” and the roller material is aluminum.

  The third graph G3 shows the amount of deviation when the roller has an eccentric amount “0.01 mm”. As shown by the third graph G3, the amount of deviation due to eccentricity often becomes a period synchronized with the rotation period of the roller. Further, the amount of deviation due to eccentricity is often proportional to the amount of eccentricity, but is often not accumulated.

  The fourth graph G4 shows the amount of deviation when the roller has eccentricity and thermal expansion. The thermal expansion is an example when there is a temperature change of “−10 ° C.”.

  The fifth graph G5 shows the amount of deviation when the roller has eccentricity and slippage generated between the web and the roller. Note that the slip generated between the web and the roller is an example of “0.1%”.

  Further, in order to reduce the meandering of the web, a so-called tension may be applied to pull the web in the conveyance direction. Depending on the tension, the web may stretch or shrink. Further, the expansion and contraction of the web may vary depending on the thickness, width, coating amount, etc. of the web.

  FIG. 23 is a diagram illustrating a processing result example by the overall processing according to the comparative example. The illustrated comparative example is an example in which the position variation shown in FIG. 14 is present, and the detection range RA is fixed by default. In the example shown in the figure, when the detection range RA is fixed, a position that does not fall within the detection range RA appears in the second and subsequent fluctuation cycles CYC. As described above, it is difficult for the sensor to detect a position outside the detection range RA.

<Example of sensor location>
Desirably, the position where the detection unit 110F10 performs detection, that is, the position where the sensor is installed, is preferably a position close to the landing position such as the black landing position PK, such as the inter-black roller INTK1. That is, when the detection is performed by the inter-black roller INTK1 or the like, the image forming apparatus 110 can detect the position of the conveyed object with high accuracy.

  Further, preferably, the position where the detection unit 110F10 performs detection, that is, the position where the sensor is installed is the position upstream of the landing position among the rollers as in the black upstream section INTK2. good. That is, when detection is performed in the black upstream section INTK2 or the like, the image forming apparatus 110 can accurately detect the position or the like of the conveyed object.

  As shown in the figure, the first roller is provided for each liquid ejection head unit. Specifically, in the example illustrated in FIG. 2, the number of first rollers is four, which is the same number as the liquid discharge head unit. The first roller is a roller used to transport the recording medium to a landing position where the liquid ejection head unit can eject the liquid to a predetermined portion of the recording medium. That is, the first roller is a roller installed on the upstream side from each landing position. For example, in the case of black, the first roller is the first black roller CR1K (FIG. 2).

  As shown in the figure, the second roller is provided for each liquid ejection head unit. Specifically, in the example illustrated in FIG. 2, the number of second rollers is four, which is the same number as the liquid discharge head unit. The second roller is a roller used to transport the recording medium from the landing position to another position. That is, a 2nd roller is a roller installed downstream from each landing position. For example, in the case of black, the second roller is a black second roller CR2K (FIG. 2).

  For example, for black, the position where the sensor is installed is as follows.

  FIG. 24 is a diagram illustrating an example of a position where a sensor is installed in the apparatus for ejecting liquid according to an embodiment of the present invention. Hereinafter, description will be made by taking black in the configuration shown in FIG. 2 as an example.

  In this example, the black sensor SENK is preferably installed between the first black roller CR1K and the second black roller CR2K and closer to the first black roller CR1K than the black landing position PK. . The distance approaching the first black roller CR1K is determined based on the time required for the control operation. For example, the distance approaching the first black roller CR1K is “20 mm”. In this case, the position where the black sensor SENK is installed is an example of “20 mm” upstream from the black landing position PK.

  In this example, the black sensor SENK detects the position POS of the web 120 in the orthogonal direction. For example, the position POS is the position of an edge portion on the web 120. The position POS is not limited to the position of the edge part, and may be the position of another part. As shown in the drawing, the position where the black sensor SENK is installed is upstream of the black landing position PK and is a different position. In such a case, a detection error E1 occurs between the position POS at the black landing position PK and the position POS at the position where the black sensor SENK is installed. The detection error E1 becomes smaller as the distance between the position where the black sensor SENK is installed and the black landing position PK is shorter.

  Thus, when the position where the first sensor is installed is close to the landing position, the detection error E1 becomes small. Further, when the detection error E1 is small, the image forming apparatus can land each color liquid with high accuracy. For this reason, when image formation is performed, the image forming apparatus landes each color liquid with high accuracy, so that color misregistration can be reduced and the image quality of the formed image can be improved.

  FIG. 25 is a schematic diagram illustrating an example of arrangement of sensors in a device for ejecting liquid according to an embodiment of the present invention. For example, each sensor is arranged at a position where the end of the web 120 as shown in the figure can be detected.

  First, each sensor is provided at a position or the like facing each liquid ejection head unit with the web 120 interposed therebetween. Each sensor includes, for example, a light emitting element that irradiates the web 120 with laser light or the like, and an imaging element that images a region irradiated with light by the light emitting element.

  Since the laser light emitted from the light emitting element interferes with the scattered waves scattered on the surface of the web 120, a speckle pattern or the like is generated. And the image pick-up element which each sensor has images such a speckle pattern etc., and produces | generates an image. Thus, based on the change in the position of the pattern imaged by the imaging element, for example, the image forming apparatus can determine the amount of movement to move each liquid ejection head unit.

  Further, in the illustrated configuration, each liquid ejection head unit and each sensor includes at least a part of each image formation area where each liquid ejection head unit forms an image and each detection area where each sensor detects. It is desirable that the positions overlap each other.

<Modification>
Note that the detection unit 110F10 captures images twice with one sensor, compares the images generated by the respective image captures, and outputs detection results such as the position of the web 120, the amount of movement, the movement speed, or a combination thereof. May be.

  For example, in the embodiment according to the present invention, the transport device may move the head unit in the orthogonal direction based on the detection result. First, the transport apparatus may have, for example, the following moving mechanism.

  FIG. 26 is a block diagram illustrating an example of a moving mechanism for moving a liquid discharge head unit included in a liquid discharge apparatus according to an embodiment of the present invention. For example, the moving mechanism is realized by hardware as illustrated. The illustrated example is an example of a moving mechanism that moves the cyan liquid discharge head unit 210C.

  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. A control device CTRL 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 detection result is input to the control device CTRL. Then, the control device CTRL moves the cyan liquid ejection head unit 210C by the actuator ACT so as to compensate for the variation in the position of the web 120 indicated by the detection result.

  In the illustrated example, the detection result is, for example, a fluctuation Δ. Therefore, in this example, the control device CTRL moves the cyan liquid ejection head unit 210C in the orthogonal direction 20 so as to compensate for the variation Δ.

  If there is a moving part realized by such a moving mechanism or the like, each liquid discharge head unit can be moved during the process. Therefore, the conveying device can be moved by “meandering” or the like during the process. Even if fluctuates in the orthogonal direction 20, processing can be performed with high accuracy.

  The embodiment according to the present invention may be realized by a transport system such as a system that ejects liquid having one or more devices. For example, the black liquid discharge head unit 210K and the cyan liquid discharge head unit 210C are apparatuses in the same casing, and the magenta liquid discharge head unit 210M and the yellow liquid discharge head unit 210Y are apparatuses in the same casing, both of which are included. You may implement | achieve by the system which discharges a liquid.

  Further, in the apparatus for ejecting liquid and the system for ejecting liquid according to the present invention, the liquid is not limited to ink, and may be another type of recording liquid or fixing processing liquid. In other words, the apparatus for ejecting liquid and the system for ejecting liquid according to the present invention may be applied to an apparatus for ejecting a liquid of a type other than ink.

  Therefore, the apparatus for ejecting liquid and the system for ejecting liquid according to the present invention are not limited to forming an image. For example, the formed object may be a three-dimensional structure.

  Note that the first support member and the second support member may be combined. For example, the first support member and the second support member may have the following configurations.

  FIG. 27 is a schematic view showing a modification of the apparatus for ejecting liquid according to an embodiment of the present invention. Compared to FIG. 2, the arrangement of the first support member and the second support member is different in the illustrated configuration. As illustrated, the first support member and the second support member may be realized by, for example, the first member RL1, the second member RL2, the third member RL3, the fourth member RL4, and the fifth member RL5. . That is, the second support member provided on the upstream side of each liquid discharge head unit and the first support member provided on the downstream side of each liquid discharge head unit may be combined. Note that the first support member and the second support member may be combined with a roller or a curved plate.

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

  The present invention can also be applied to an apparatus that performs some processing on a transported object using line-shaped head units arranged in a direction orthogonal to the transport direction.

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

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

  In the embodiment according to the present invention, the present invention may be realized by a program for causing a computer to execute a part or all of a processing method such as causing a computer to discharge a liquid, such as a transport device, an information processing device, or a combination thereof. Good.

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

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

Japanese Patent Laying-Open No. 2015-13476

Claims (18)

A transport device that has a head unit and performs processing on the transported object by the head unit,
A detection unit that is installed for each head unit and outputs a detection result indicating the position, moving speed, moving amount, or a combination of the objects to be conveyed;
A statistical value calculation unit for calculating a statistical value of the position based on a plurality of the detection results;
A conveyance device comprising: a setting unit that sets a detection range in which the detection unit performs detection based on the statistical value. The transport apparatus according to claim 1, wherein the statistical value includes an average value, a median value, or a moving average value of the positions. The said setting part sets the said detection range so that the value based on the maximum value of the said position, the minimum value, the standard deviation, or the value based on the integral multiple of the said standard deviation may be included. The conveying apparatus as described in. The said setting part changes the said detection range, if the said statistical value changes more than predetermined value, The conveying apparatus of any one of Claim 1 thru | or 3 characterized by the above-mentioned. The transport apparatus according to claim 1, wherein the statistical value calculation unit calculates the statistical value for each fluctuation period of the position. A first support member provided on an upstream side in a transport direction in which the transported object is transported from a processing position where the head unit performs the processing on a predetermined portion of the transported object;
A second support member provided downstream of the processing position in the transport direction;
With
The transport apparatus according to claim 1, wherein the detection unit is provided between the first support member and the second support member. The transport apparatus according to claim 6, wherein the detection unit is installed at a position closer to the first support member than the processing position. The transport device according to claim 1, wherein the detection unit uses an optical sensor. The transport device according to claim 1, wherein the detection unit obtains the detection result based on a pattern of the transported object. Each of the detecting units detects the position, the moving speed, the moving amount, or a combination thereof for each head unit based on the patterns detected at two or more different timings. The transport apparatus according to claim 9. The pattern is generated by interference of light applied to the uneven shape formed on the transported object,
The transport device according to claim 9, wherein the detection unit obtains the detection result based on an image obtained by capturing the pattern. The transport apparatus according to claim 1, wherein when the processing is performed, an image is formed on the transported object. The transport apparatus according to claim 1, wherein the object to be transported is a sheet that is continuously long along a transport direction. Based on the detection result, further comprising a control unit for causing the head unit to perform the processing,
14. The transport according to claim 1, wherein the control unit generates each timing at which the head unit performs the processing for each head unit based on the detection result. apparatus. The control unit generates the timing by calculating a time required for the transported object to be transported to a processing position where the head unit performs processing based on the detection result. Item 15. The transport device according to Item 14. A measuring unit for measuring the amount of movement of the object to be conveyed;
The transport device according to claim 14 or 15, wherein the control unit performs the processing based on a movement amount measured by the measurement unit and the detection result. A transport system having a head unit and having one or more devices that perform processing on the transported object by the head unit,
A detection unit that is installed for each head unit and outputs a detection result indicating the position, moving speed, moving amount, or a combination of the objects to be conveyed;
A statistical value calculation unit for calculating a statistical value of the position based on a plurality of the detection results;
A conveyance system comprising: a setting unit that sets a detection range in which the detection unit performs detection based on the statistical value. A processing method performed by an apparatus that has a head unit and performs processing on a transported object by the head unit,
A detection procedure in which the apparatus is installed for each head unit and outputs a detection result indicating a position, a moving speed, a moving amount, or a combination of the transferred object;
A statistical value calculation procedure in which the apparatus calculates a statistical value of the position based on a plurality of the detection results;
And a setting procedure for setting a detection range in which detection is performed in the detection procedure based on the statistical value.

Images