JP2017167130A - Conveyance target object detection device, conveying device, and conveyance target object detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect the position of a conveyance target object.SOLUTION: A conveyance target object detection device comprises an optical sensor that receives light reflected on a conveyance target object, outputs, by using the optical sensor, a detection result indicating the position, speed of travel, and amount of travel, or combination of these of the conveyance target object in at least either one of a conveyance direction in which the conveyance target object is conveyed or a direction orthogonal to the conveyance direction, and sets an f number and exposure time related to the optical sensor on the basis of the detection result.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transported object detection device, a transport device, and a transported object detection method.

  Conventionally, methods for performing various processes using a head unit are known. For example, a method of forming an image by a so-called ink jet method in which ink is ejected from a print head is known. 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, in order to further improve the image quality of an image to be formed, it may be required to detect the landing position of the discharged liquid with high accuracy. For example, when the landing position shift occurs, the image quality deteriorates. On the other hand, in the conventional technology, there is a problem that the position or the like of the conveyed object may not be detected with high accuracy.

  An object of one aspect of the present invention is to provide a transported object detection device that accurately detects the position of a transported object.

In order to solve the above-described problem, a transported object detection device according to one aspect of the present invention includes an optical sensor that receives light reflected by a transported object,
Using the optical sensor, a detection result indicating a position, a moving speed, a moving amount, or a combination of these objects in at least one of a conveying direction in which the object is conveyed or a direction orthogonal to the conveying direction A detector that outputs
A setting unit configured to set an aperture value and an exposure time related to the optical sensor based on the detection result.

  The position of the object to be conveyed can be detected with high accuracy.

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 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 functional block diagram which shows an example of a function structure using the detection part which concerns on one Embodiment of this invention. FIG. 6 is a diagram illustrating an example in which the position of a recording medium varies in an orthogonal direction. It is a figure which shows an example of the cause which color misregistration occurs. 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 flowchart which shows an example of the whole process by the apparatus which discharges the liquid which concerns on one Embodiment of this invention. It is a figure which shows an example of the aperture stop which the apparatus which discharges the liquid which concerns on one Embodiment of this invention has. It is a figure which shows an example of the test pattern which the apparatus which discharges the liquid which concerns on one Embodiment of this invention uses. It is a figure which shows the example of a process result of the whole process by the apparatus which discharges the liquid which concerns on one Embodiment of this invention. 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 figure which shows an example of the hardware constitutions in a 1st comparative example. It is a figure which shows the example of a process result of the whole process by the apparatus which discharges the liquid which concerns on a 1st comparative example. It is a figure which shows the example of a process result of the whole process by the apparatus which discharges the liquid which concerns on a 2nd comparative example. It is a figure which shows an example of the position in which the sensor in the apparatus which discharges the liquid which concerns on a comparative example is installed. It is a functional block diagram which shows an example of a function structure of the apparatus which discharges the liquid which concerns on one Embodiment of this invention. 1 is a block diagram illustrating an example of a hardware configuration for moving a liquid discharge head unit included in a liquid discharge apparatus according to an embodiment of the present invention. It is the schematic which shows the 1st modification of the hardware constitutions which implement | achieve the detection part which concerns on one Embodiment of this invention. It is the schematic which shows the 2nd modification of the hardware constitutions which implement | achieve the detection part which concerns on one Embodiment of this invention. It is the schematic which shows the 3rd modification of the hardware constitutions which implement | achieve the detection part which concerns on one Embodiment of this invention. It is the schematic which shows an example of the some imaging lens used for the detection part which concerns on one Embodiment of this invention. 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 an example of the orthogonal direction 20. Further, in this example, the image forming apparatus 110 ejects each of the four colors of ink in the order of black (K), cyan (C), magenta (M), and yellow (Y), and a predetermined portion of the web 120. Inkjet printer for forming an image on

  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 discharges each liquid of each color to the web 120 conveyed in the conveyance direction 10. The web 120 is transported by two pairs of nip rollers, a roller 230, and the like. 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. As described above, the position at which ink is ejected (hereinafter referred to as “landing position”) is substantially equal to the position at which the liquid ejected from the liquid ejecting head lands on the recording medium, that is, immediately below the liquid ejecting head. . 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, black ink is ejected to the landing position (hereinafter referred to as “black landing position PK”) of the black liquid discharge head unit 210K. Similarly, cyan ink is ejected to the landing position of the cyan liquid ejection head unit 210C (hereinafter referred to as “cyan landing position PC”). Further, the magenta ink is ejected to the landing position of the magenta liquid ejection head unit 210M (hereinafter referred to as “magenta landing position PM”). The yellow ink is ejected to the landing position (hereinafter referred to as “yellow landing position PY”) of the yellow liquid ejection head unit 210Y. Each timing at which each liquid ejection head unit ejects ink is controlled by a 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. As shown in the drawing, the plurality of rollers are installed, for example, on the upstream side in the transport direction and on the downstream side in the transport direction with each liquid ejection 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” can be 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 a curved plate or the like having a circular arc at a portion in contact with the conveyed object. 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 eject black ink. 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.

  An example of the outer shape of the liquid discharge head unit will be described with reference to FIG. First, FIG. 3A is a schematic plan view showing an example of four liquid discharge head units 210K to 210Y of the image forming apparatus 110 according to the embodiment of the present invention.

  As shown in FIG. 3A, the liquid ejection head unit is, for example, a line type head unit. That is, the image forming apparatus 110 includes four liquid discharge 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 embodiment, the black (K) liquid discharge head unit 210K staggers the four heads 210K-1, 210K-2, 210K-3, and 210K-4 in the direction orthogonal to the conveyance direction 10 of the web 120. Arrange in a shape. Thereby, the image forming apparatus 110 can form an image in the entire width direction (direction perpendicular to the transport direction) of the image forming area (printing area) of 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 each liquid discharge head unit, the position of the recording medium in the transport direction or the orthogonal direction is detected, and a sensor which is an example of a detection unit is installed. As this sensor, an optical sensor using light such as laser, air pressure, photoelectric, ultrasonic wave or infrared ray 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. That is, the detection device is, for example, a sensor that can detect the edge of the recording medium. In addition, the detection unit is realized by, for example, the following hardware configuration.

  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. Further, the detection unit may be realized with a configuration as illustrated.

  The illustrated sensor has a configuration in which an object such as a web is illuminated to form a speckle pattern. Specifically, the sensor has a semiconductor laser light source (LD) and a collimating optical system (CL). The sensor includes a CMOS image sensor for capturing an image of a speckle pattern, and a telecentric imaging optical system (OL) for condensing and focusing the speckle pattern on the CMOS image sensor.

  In the example of the configuration shown in the figure, the CMOS image sensor captures speckle pattern images at different times T1 and T2. Further, the cross correlation calculation is performed by the FPGA circuit using the speckle pattern image captured at time T1 and the speckle pattern image captured at time T2. Based on the movement of the correlation peak position calculated by the cross-correlation calculation, the CMOS image sensor outputs the movement amount of the object from time T1 to time T2 in the imaged range. In the example shown in the figure, the size of the sensor is W × D × H = 15 × 60 × 32 [mm].

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

  The correlation calculation is calculated as follows, for example.

<Example of correlation calculation>
FIG. 6 is a block diagram showing an example of a correlation calculation method according to an embodiment of the present invention. For example, the detection unit can calculate the relative position of the web, the moving amount, the moving speed, or a combination of these at the position of the sensor by 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. 7 is a diagram showing 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 (FIG. 6) 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. 8 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 the “correlation peak” shown in the figure is searched for by the peak position search unit SR (FIG. 6).

  Returning to FIG. 6, 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.

  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.

  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 also shifted | deviated also to the X direction.

  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.

  FIG. 9 is a functional block diagram showing an example of a functional configuration using the detection unit according to the embodiment of the present invention. Hereinafter, as illustrated, a combination of the black liquid discharge head unit 210K and the cyan liquid discharge head unit 210C among the detection units installed for each liquid discharge 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 of the web 120, the moving speed at which the web 120 is conveyed, and the amount of movement 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 movement amount 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. 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.

  Specifically, when the moving speed is V [mm / s] and the relative distance L [mm] is an interval set in the transport direction 10, it can be expressed by the following equation (1).

Δt = L / V (1)

In the above equation (1), the relative distance L [mm] is an interval between “A position” and “B position” shown in FIG. 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.

  As shown in FIG. 9, the positions where imaging is performed by the imaging unit are constant intervals in the transport direction 10. Then, the web 120 is imaged at each position by each imaging unit. Thus, based on the speckle pattern, the image forming apparatus can obtain a detection result indicating the position of the web 120 with high accuracy in the transport direction or the orthogonal direction.

  Further, the detection result may indicate a relative position. Specifically, the relative position indicates a difference between a position detected by one of the sensors and a position detected by a different sensor. In addition, the relative position may be a difference between positions in a plurality of images obtained by any one of the sensors. That is, for example, the relative position may be a difference between the position detected in the previous frame and the position detected in the next frame. Thus, the relative position indicates the amount of deviation from the position detected by the previous frame or other sensor.

  The sensor may detect the position in the orthogonal direction and the like. The sensor may also be used to detect the respective positions in the transport direction and the orthogonal direction. When used in this manner, the cost can be reduced in each direction. And since the number of sensors can be reduced, it can also save space.

  Further, the calculation unit 53F performs a cross-correlation operation on the image data D1 (n) and D2 (n) indicating the images 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 output from the controller 520, the second signal SIG2 for the cyan liquid discharge head unit 210C, and the like. As shown in the drawing, based on the result of calculation by the calculation unit 53F, the control unit 54F outputs a signal to control the timing. Note that the control unit 54F is realized by, for example, the controller 520 or the like.

  Further, the calculation unit 53F outputs the moving speed V calculated based on the detection result to the setting unit 55F. Then, the setting unit 55F calculates the aperture value, the exposure time, or both based on the moving speed V received from the outside such as the calculation unit 53F. Further, the moving speed V may be input to the setting unit 55F based on the operation mode such as the resolution of the output image of the image forming apparatus. The setting unit 55F is realized by, for example, the control device 52 (FIG. 4).

  If the moving speed V is high, the setting unit 55F shortens the exposure time and decreases the aperture value. On the other hand, when the moving speed V is low, the setting unit 55F lengthens the exposure time and increases the aperture value.

  Then, the aperture controllers 143A and 143B control the aperture so that the aperture value set by the setting unit 55F is obtained. The aperture controllers 143A and 143B are realized by, for example, the control device 52 (FIG. 4) and the actuator ACA (FIG. 16).

  Similarly, the shutter control units 141A and 141B control the shutter speed and the like so that the exposure time set by the setting unit 55F is reached.

  In this way, the detection unit can capture an image based on the exposure time and the aperture value corresponding to the moving speed V. The calculation and setting may be performed by the controller 520 or the like.

  Returning to FIG. 2, in the following description, a sensor installed for the black liquid discharge head unit 210K is referred to as a “black sensor SENK”. Similarly, a sensor installed for the cyan liquid ejection head unit 210C is referred to as “cyan sensor SENC”. Further, a sensor installed for the magenta liquid ejection head unit 210M is referred to as “magenta sensor SENM”. Furthermore, a sensor installed for the yellow liquid discharge head unit 210Y is referred to as “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 devices used for detection or the like at the “position where the sensor is installed”, and devices other than the sensor may be installed at other positions that are connected by a cable or the like. Note that the black sensor SENK, cyan sensor SENC, magenta sensor SENM, and yellow sensor SENY shown in FIG. 2 are examples of positions where the sensors are installed.

  Thus, the position where the sensor is installed is desirably 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. As the distance between each landing position and the sensor becomes shorter, the error in detection can be reduced. Therefore, the image forming apparatus can accurately detect the position of the recording medium in the transport direction or the orthogonal direction by the sensor.

  The position close to each landing position is specifically between each first roller and each second roller. 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 recording medium in the transport direction or the orthogonal direction.

  Desirably, the position where the sensor is installed is preferably 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 accurately positions the recording medium in the transport direction or the orthogonal direction. It can be detected. Furthermore, when a sensor is installed at such a position, the sensor is installed upstream from each landing position. Therefore, the image forming apparatus can first detect the position of the recording medium with high accuracy in the transport direction or the orthogonal direction by the sensor on the upstream side, and calculate the ejection timing of each liquid ejection head unit. That is, when the web 120 is conveyed downstream while this calculation is performed, each liquid discharge head unit can discharge ink at the calculated timing.

  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, it may be restricted to set the vicinity of each landing position or the like 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.

  The image forming apparatus may further include a measurement unit such as an encoder. Hereinafter, an example in which the measurement unit is realized by an encoder will be described. Specifically, the encoder is installed with respect to the rotation shaft of the roller 230, for example. In this way, the movement amount in the transport direction can be measured based on the rotation amount of the roller 230. When this measurement result is used together with the detection result by the sensor, the image forming apparatus can discharge the liquid onto the web 120 with higher accuracy.

  FIG. 10 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. 10A will be described (in the figure, the web 120 is conveyed from the bottom to the top). 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. 10B, for example. That is, the web 120 may “meander” as shown in FIG.

  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.

  FIG. 11 is a diagram illustrating an example of a cause of color misregistration. As described with reference to FIG. 10, when the position of the recording medium fluctuates in the orthogonal direction, that is, “meandering” occurs, color misregistration is likely to occur due to the cause shown in FIG.

  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. That is, the color misalignment 330 occurs because the line formed by the ink ejected by each liquid ejection head unit is misaligned 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.

<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. 12 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. Further, the storage unit 110F3 illustrated in FIG. 8 is realized by, for example, the storage device 72Cm. Furthermore, the speed calculation unit 110F4 illustrated in FIG. 8 is realized by, for example, the CPU 72Cp. Note that the storage unit 110F3 and the speed calculation unit 110F4 may be realized by other calculation devices and storage devices.

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

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

  The logic circuit 72ECl stores the image data input from the host device 71 in the storage device 72ECm based on the control signal input from the printer controller 72C (FIG. 12).

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

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

  The output control device 72Eic controls a plurality of liquid ejection head units simultaneously or individually. That is, the output control device 72Eic performs control to change the timing at which each liquid ejection head unit ejects liquid in response to timing input. Note that 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 (FIG. 12). Further, the output control device 72Eic may control any of the liquid ejection head units based on an operation by the user.

  Note that the printer device 72 shown in FIG. 12 has different routes for inputting image data from the host device 71 and routes used for transmission / reception between the host device 71 and the printer device 72 based on the control data. It is an example.

  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 (FIG. 12) is an actuator, a mechanism, a driver device, 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 overall processing>
FIG. 15 is a flowchart illustrating an example of the entire process performed by the apparatus for ejecting liquid according to an embodiment of the present invention. Further, the entire process shown in the figure is an example of a transported object detection method performed by the transported object detection device included in the image forming apparatus 110.

  For example, it is assumed that image data indicating an image formed in advance on the web 120 (FIG. 1) is input to the image forming apparatus 110. Next, the image forming apparatus 110 performs the entire process shown in FIG. 15 based on the image data, and forms an image indicated by the image data on the web 120.

  In step S01, the image forming apparatus detects the moving speed in the transport direction or the orthogonal direction. That is, in step S01, the image forming apparatus detects the moving speed at which the web 120 is conveyed in at least one of the conveyance direction and the orthogonal direction by the sensor.

  In step S02, the image forming apparatus determines whether the moving speed has been changed based on the moving speed detected in step S01. Next, when it is determined that the moving speed has been changed (YES in step S02), the image forming apparatus proceeds to step S03. On the other hand, if it is determined that the moving speed has not been changed (NO in step S02), the image forming apparatus ends the process.

  In step S03, the image forming apparatus calculates an aperture value and an exposure time. For example, the aperture value and the exposure time are calculated based on the following equation (4).

  In step S04, the image forming apparatus sets the shutter speed and the like so as to be the exposure time calculated in step S03.

  In step S05, the image forming apparatus sets the aperture value calculated in step S03.

  FIG. 16 is a diagram illustrating an example of a diaphragm included in an apparatus for ejecting liquid according to an embodiment of the present invention. When the processing shown in FIG. 15 is performed, for example, the aperture is as illustrated.

  Hereinafter, an example in which an electric iris diaphragm (iris) as illustrated is used will be described. As shown in the drawing, the aperture range of the aperture DIA is changed based on the set aperture value. When the moving speed is fast, the image is likely to be blurred. In particular, shaking is likely to occur in the transport direction. In order to reduce the influence of such blurring, the influence of blurring can be reduced by increasing the shutter speed, that is, shortening the exposure time.

  When the exposure time is shortened, the exposure amount tends to decrease. As described above, when the exposure time is shortened, the captured image tends to be dark. When the image is dark, the calculation accuracy due to the image correlation tends to decrease. Therefore, the detection accuracy such as the position, the moving speed, or the moving amount detected by the detecting unit is likely to be lowered.

  Therefore, when the moving speed V is high, the image forming apparatus opens the aperture so that a large amount of light is received. In this way, the image forming apparatus can capture a bright image. When the image is bright, the image forming apparatus can improve the S / N ratio of the image, and the image forming apparatus can improve the accuracy of detecting the position and the like.

  Moreover, in order to make it bright, the method of strengthening illumination light can be considered. On the other hand, it is desirable that the illumination light is weak in view of energy or safety. In order to improve the position detection accuracy, it is desirable to increase the resolution per pixel by increasing the number of pixels used in the calculation or increasing the optical magnification. Therefore, when an aperture value or the like is set as in the embodiment according to the present invention, illumination light or the like can be weakened.

  The aperture value may be a continuous set value or a discrete set value.

  Further, when there is a light source variation or CMOS sensor sensitivity variation, the image forming apparatus may adjust the amount of received light based on the variation.

  In step S03 shown in FIG. 15, the aperture value is calculated so that the received light amount is inversely proportional to the exposure time determined by the moving speed V. For example, the aperture value is calculated by the following equation (4).

I = Io × (NA × Mo) ²
Depth of focus = ± k × wavelength / {2 × (numerical aperture) ² } (4)

In the above formula (4), “I” indicates the brightness of the image. “Io” indicates the brightness of the sample surface. Further, in the above equation (4), “NA” indicates a numerical aperture that is an example of an aperture value. In the above formula (4), “Mo” indicates the magnification of the objective lens. In other words, the numerical aperture is set for the stop. In the case expressed by the above equation (4), the amount of received light is proportional to the square of the numerical aperture. Therefore, when the exposure time is "1/2" times, the numerical aperture is "√2" times. The

  Note that the image forming apparatus may store the exposure time and the aperture value corresponding to the moving speed in a lookup table or the like by experiments or evaluations performed in advance. Then, the setting unit 55F may specify an exposure time and an aperture value corresponding to the moving speed from a lookup table or the like, and set the exposure time and the aperture value.

  FIG. 17 is a diagram illustrating an example of a test pattern used by an apparatus for ejecting liquid according to an embodiment of the present invention. First, as shown in the drawing, the image forming apparatus performs test printing so that a straight line is formed in the transport direction 10 with black as an example of the first color. The distance Lk from the edge is obtained from the result of this test printing. In this manner, when the distance Lk from the edge is adjusted manually or by an apparatus in the orthogonal direction, the position at which the first color, that is, the black ink serving as the reference is ejected is determined. Note that the method for determining the position at which the black ink is ejected is not limited to this method.

  FIG. 18 is a diagram illustrating an example of a processing result of the overall processing by the apparatus for ejecting liquid according to an embodiment of the present invention. For example, as shown in FIG. 18A, it is assumed that image formation is performed in the order of black, cyan, magenta, and yellow. FIG. 18B is a plan view of FIG. 18A viewed from above, a so-called plan view. Hereinafter, an example in which the roller 230 is eccentric will be described. Specifically, it is assumed that there is an eccentric EC as shown in FIG. As described above, when there is an eccentric EC, a shaking OS is generated in the roller 230 when the web 120 is conveyed. As described above, when the shaking OS occurs, the position POS of the web 120 changes. That is, “meandering” is generated by the shaking OS.

  In order to reduce the color misregistration with respect to black, the image forming apparatus subtracts the current position of the recording medium detected by the sensor and the position of the recording medium one cycle before, thereby changing the position of the recording medium. calculate. Specifically, first, the difference between the position of the web 120 detected by the black sensor SENK and the position of the web 120 under the black liquid discharge head unit 210K is defined as “Pk”. Similarly, the difference between the position of the web 120 detected by the cyan sensor SENC and the position of the web 120 under the cyan liquid discharge head unit 210C is defined as “Pc”. Further, the difference between the position of the web 120 detected by the magenta sensor SENM and the position of the web 120 under the magenta liquid ejection head unit 210M is defined as “Pm”. Furthermore, the difference between the position of the web 120 detected by the yellow sensor SENY and the position of the web 120 under the yellow liquid discharge head unit 210Y is defined as “Py”.

Subsequently, the position where the liquid is landed by each liquid discharge head unit and the distance from the edge of the web 120, that is, the edge of the web 120, for each color, “Lk3”, “Lc3”, “Lm3”, and “Ly3”. " In such a case, since the position of the web 120 is detected by the sensor, “Pk = 0”, “Pc = 0”, “Pm = 0”, and “Py = 0”. From this relationship, the following relationship (5) can be shown.

Lc3 = Lk3-Pc = Lk3
Lm3 = Lk3
Ly3 = Lk3-Py = Lk3 (5)

Therefore, from the above equation (5), “Lk3 = Lm3 = Lc3 = Ly3”. In this manner, the image forming apparatus can further improve the accuracy of the landing position of the discharged liquid in the orthogonal direction by moving each liquid discharge head unit to change the position of the web 120. Further, when image formation is performed, each color liquid is landed with high accuracy, so that color misregistration can be reduced and the image quality of the formed image can be improved.

  The sensor is preferably installed at a position closer to the first roller than the landing position.

  FIG. 19 is a diagram illustrating an example of a position where a sensor is installed in a device for ejecting liquid according to an embodiment of the present invention. Hereinafter, black will be described 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.

  Thus, when the position where the 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.

  Further, with such a configuration, for example, there is no restriction that the distance between the liquid discharge head units must be an integral multiple of the circular length d (FIG. 18) of the roller, so the liquid discharge head unit is installed. The position can be freely set. That is, the image forming apparatus can land each color liquid with high accuracy even when the distance between the liquid discharge head units is a non-integer multiple of the circular length d of the roller.

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

  FIG. 21 is a diagram illustrating a processing result example of the overall processing by the apparatus for ejecting liquid according to the first comparative example. In this comparative example, the liquid discharge head units are installed so that the distance between the liquid discharge head units is an integral multiple of the circular length d of the roller. In this case, the difference between the web position detected by each sensor and the web position immediately below the liquid discharge head unit is “0”. Therefore, in this comparative example, if the landing positions of the liquid on the ink webs of the respective colors are the distances “Lk1”, “Lc1”, “Lm1” and “Ly1” from the web edge, “Lk1 = Lc1 = Lm1 = Ly1” " In this way, the positional deviation is corrected.

  FIG. 22 is a diagram illustrating a processing result example of the entire processing by the apparatus for ejecting liquid according to the second comparative example. Note that the second comparative example has the same hardware configuration as the first comparative example. Compared to the first comparative example, the second comparative example is different in that the distance between the black and cyan liquid ejection head units and the distance between the magenta and yellow liquid ejection head units are “1.75d”, respectively. That is, the second comparative example is an example in which the distance between the black and cyan liquid discharge head units and the distance between the magenta and yellow liquid discharge head units are each a non-integer multiple of the circle length d of the roller.

In this second comparative example, the difference between the web position detected by the black sensor SENK and the web position under the black liquid discharge head unit 210K is defined as “Pk”. Similarly, the difference between the web position detected by the cyan sensor SENC and the web position under the cyan liquid discharge head unit 210C is defined as “Pc”. Further, the difference between the position of the web detected by the magenta sensor SENM and the position of the web 120 under the magenta liquid ejection head unit 210M is defined as “Pm”. Furthermore, the difference between the position of the web detected by the yellow sensor SENY and the position of the web 120 under the yellow liquid discharge head unit 210Y is defined as “Py”. Further, in the second comparative example, when the landing positions of the liquid on the ink webs of the respective colors are the distances “Lk2,” “Lc2,” “Lm2,” and “Ly2” from the web edge, the following equation (6) is obtained. Can show the relationship.

Lc2 = Lk2-Pc
Lm2 = Lk2
Ly2 = Lk2-Py (6)

Therefore, “Lk2 = Lm2 ≠ Lc2 = Ly2”. Thus, when the distance between the liquid discharge head units is a non-integer multiple of the circular length d of the roller, in this comparative example, the position of the web immediately below the cyan liquid discharge head unit 210C and the magenta liquid discharge head unit 210M. Is different by “Pc” and “Py”. For this reason, web position fluctuations are not compensated, and color misregistration or the like is likely to occur.

  FIG. 23 is a diagram illustrating an example of a position where a sensor is installed in the apparatus for ejecting liquid according to the comparative example. As shown in the figure, in the comparative example, the sensor is installed at a position far from the landing position. Therefore, the detection error E2 in the comparative example often becomes large.

<Functional configuration example>
FIG. 24 is a functional block diagram showing an example of a functional configuration of a device for ejecting liquid according to an embodiment of the present invention. As illustrated, the image forming apparatus 110 includes a plurality of liquid ejection head units and a detection unit 110F10 for each liquid ejection head unit. In addition, the image forming apparatus 110 includes a control unit 54F as illustrated. The conveyed object detection device 60 included in the image forming apparatus 110 includes a detection unit 110F10 and a setting unit 55F.

  As shown in the drawing, the detection unit 110F10 is provided for each liquid ejection head unit. Specifically, in the example illustrated in FIG. 2, the number of detection units 110F10 is four as illustrated. The detection unit 110F10 detects the position or movement amount of the recording medium in the conveyance direction or the orthogonal direction of the web 120. The detection unit 110F10 is realized by, for example, the hardware configuration illustrated in FIG. 4 or FIG. And the detection part 110F10 outputs the detection result which shows the moving speed of the to-be-conveyed object in at least one of the conveyance direction in which a to-be-conveyed object is conveyed, or an orthogonal direction using an optical sensor. The detection unit 110F10 is the detection units 52A and 52B and the like in FIG.

  As shown in the figure, the first support member is provided for each liquid ejection head unit. Specifically, in the example illustrated in FIG. 2, the number of first support members is four, which is the same number as the liquid discharge head unit. The first support member is a roller or the like used to transport the recording medium to a landing position where the liquid ejection head unit can eject the liquid to a predetermined location of the recording medium. That is, the first support member is a first roller or the like 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 drawing, the second support member is provided for each liquid ejection head unit. Specifically, in the example illustrated in FIG. 2, the number of second support members is four, which is the same number as the liquid discharge head unit. The second support member is a roller or the like used to transport the recording medium from the landing position to another position. That is, the second support member is a second roller or the like installed on the downstream side from each landing position. For example, in the case of black, the second roller is a black second roller CR2K (FIG. 2).

  The setting unit 55F sets an aperture value and an exposure time related to the optical sensor used by the detection unit 110F10 based on the moving speed.

  As shown in the figure, it is desirable that the image forming apparatus 110 has a functional configuration further including a moving unit 110F20 that moves each of the liquid discharge head units based on the detection result. For example, the moving unit 110F20 is realized by the following hardware configuration.

  FIG. 25 is a block diagram illustrating an example of a hardware configuration for moving a liquid discharge head unit included in a liquid discharge apparatus according to an embodiment of the present invention. Hereinafter, a hardware configuration example for moving the cyan liquid discharge head unit 210 </ b> C will be described as shown in the drawing.

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

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

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

  The detection result by the detection unit 110F10 (FIG. 24) is input to the actuator controller CTL. Then, the actuator controller CTL 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 indicates, for example, a variation Δ. Therefore, in this example, the actuator controller CTL moves the cyan liquid discharge head unit 210C in the orthogonal direction 20 so as to compensate for the variation Δ.

  Note that the hardware of the controller 520 shown in FIG. 2 and the like and the hardware for moving the illustrated liquid discharge head unit may be integrated or may be separate.

  Referring back to FIG. 24, 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. good. That is, when the detection is performed by the inter-black roller INTK1 (FIG. 2) or the like, the image forming apparatus 110 can accurately detect the position of the recording medium in the transport direction or the orthogonal direction.

  More preferably, the position where the detection unit 110F10 performs detection, that is, the position where the sensor is installed is upstream of the landing position among the rollers as in the black upstream section INTK2 (FIG. 2). Better position. That is, when the detection is performed in the black upstream section INTK2 or the like, the image forming apparatus 110 can accurately detect the position of the recording medium in the transport direction or the orthogonal direction.

  As described above, the image forming apparatus 110 can calculate the timing at which each liquid ejection head unit ejects, the amount by which each liquid ejection head unit is moved, or a combination thereof based on the detection result by the detection unit 110F10.

  That is, when the position is detected on the upstream side, and then the web 120 is transported to the landing position on the downstream side, the timing for discharging the liquid, the movement of the liquid discharge head unit, or a combination thereof is performed during that time. Is called. Therefore, each liquid discharge head unit can accurately change the landing position in the transport direction, the orthogonal direction, or both directions.

<Summary>
An apparatus for ejecting liquid according to an embodiment of the present invention includes a transported object detection device having an optical sensor or the like. And the to-be-conveyed object detection apparatus 60 is provided with the detection part 110F10 and the setting part 55F, and sets an aperture value and exposure time based on a moving speed. As a result, the transported object detection device 60 can accurately detect the position of the transported object in the transport direction or the orthogonal direction.

  An apparatus for discharging a liquid according to an embodiment of the present invention detects the position of a transported object such as a recording medium in a transport direction or an orthogonal direction at a position close to the liquid discharge head unit for each liquid discharge head unit. Next, the apparatus for ejecting liquid according to an embodiment of the present invention moves the liquid ejection head unit based on the detection result. Therefore, compared with the first comparative example and the second comparative example, the apparatus for ejecting the liquid according to one embodiment of the present invention is not In the orthogonal direction, it is possible to accurately compensate for the deviation generated at the liquid landing position.

  Further, in the apparatus for ejecting liquid according to an embodiment of the present invention, as in the first comparative example, each liquid ejection head unit need not be arranged at a position obtained by multiplying the circumferential length of the roller by an integral number. It is possible to reduce restrictions on installing the discharge head unit. In the first comparative example and the second comparative example, adjustment is not possible without an actuator in the first color, that is, in this example, black. In contrast, the apparatus for ejecting liquid according to an embodiment of the present invention can further improve the accuracy of the landing position of the ejected liquid in the transport direction or the orthogonal direction even for the first color.

  In addition, when an image is formed on a recording medium by ejecting liquid, the device for ejecting liquid according to an embodiment of the present invention causes color misregistration when the landing positions of the ejected liquids of each color become accurate. As a result, the image quality of the formed image can be improved.

<Modification>
In addition, the apparatus which discharges the liquid which concerns on one Embodiment of this invention may have a sensor further in the structure shown in FIG. For example, the apparatus for ejecting liquid may further include a sensor upstream of the black sensor SENK or downstream of the yellow sensor SENY. In other words, the device for ejecting liquid may have five or more sensors.

  The detection device 50 shown in FIG. 4 may be realized by the following hardware, for example.

  FIG. 26 is a schematic diagram illustrating a first modification of the hardware configuration that implements the detection unit according to the embodiment of the present invention. In the following description, devices similar to those described above are denoted by the same reference numerals and description thereof is omitted.

  Compared with the hardware configuration described above, the detection device is different in that it has a plurality of optical systems. That is, the hardware configuration described above is a so-called “monocular”, whereas the hardware configuration of the first modification is a “compound eye”.

  Also, in the following modification, the position where detection is performed using the first imaging lens 12A on the upstream side of the compound eye is referred to as “A position”, and the second imaging lens 12B located downstream from the first imaging lens 12A is used. The position where the detection is performed is referred to as “B position”. In the following modification, “L” is read as the distance between the first imaging lens 12A and the second imaging lens 12B.

  The web 120 which is an example of the detection target is irradiated with laser light or the like from the first light source and the second light source. The position where the first light source emits light is referred to as “A position”, and similarly, the position where the second light source applies light is referred to as “B position”.

  The first light source and the second light source have a light emitting element that emits laser light and a collimator lens that makes the laser light emitted from the light emitting element substantially parallel. Further, the first light source and the second light source are installed at a position where the laser light is irradiated from an oblique direction with respect to the surface of the web 120.

  The detection device 50 includes the area sensor 11, a first imaging lens 12A at a position facing the “A position”, and a second imaging lens 12B at a position facing the “B position”.

  The area sensor 11 is, for example, a sensor configured to form the image sensor 112 on the silicon substrate 111. It is assumed that there are an “A region 11A” and a “B region 11B” on the imaging device 112, each of which can acquire a two-dimensional image. The area sensor 11 is, for example, a CCD sensor, a CMOS sensor, a photodiode array, or the like. The area sensor 11 is accommodated in the housing 13. Further, the first imaging lens 12A and the second imaging lens 12B are held by the first lens barrel 13A and the second lens barrel 13B, respectively.

  In this example, as illustrated, the optical axis of the first imaging lens 12A coincides with the center of the “A region 11A”. Similarly, the optical axis of the second imaging lens 12B coincides with the center of the “B region 11B”. Then, the first imaging lens 12A and the second imaging lens 12B form a two-dimensional image by forming images of light on the “A region 11A” and the “B region 11B”, respectively.

  In addition, the detection apparatus 50 may have a configuration described below.

  FIG. 27 is a schematic diagram illustrating a second modification of the hardware configuration that implements the detection unit according to the embodiment of the present invention. In the following, the differences from FIG. 26, that is, the hardware configuration of the detection device 50 are extracted and illustrated. Compared with the configuration shown in FIG. 26, the configuration of the detection apparatus 50 is different in that the first imaging lens 12A and the second imaging lens 12B are integrated to form the lens 12C. On the other hand, the area sensor 11 and the like have the same configuration as shown in FIG. 26, for example.

  In this example, it is desirable to use the aperture 121 and the like so that the images of the first imaging lens 12A and the second imaging lens 12B do not interfere and form an image. As described above, when the aperture 121 or the like is used, regions where the images of the first imaging lens 12A and the second imaging lens 12B are formed can be limited. Therefore, the interference of the respective image formations can be reduced, and the detection apparatus 50 can calculate the moving speed at the upstream sensor position based on the images generated at the “A position” and the “B position”. Similarly, the moving speed can be calculated at the position of the sensor installed downstream. As described above, the image forming apparatus may control the timing of ejecting the liquid based on the difference between the moving speeds calculated on the upstream side and the downstream side.

  FIG. 28 is a schematic diagram illustrating a third modification example of the hardware configuration for realizing the detection unit according to the embodiment of the present invention. Compared with the configuration shown in FIG. 27, the configuration of the detection apparatus 50 shown in FIG. 28A is different in that the area sensor 11 is the second area sensor 11 ′. On the other hand, the configuration of the first imaging lens 12A, the second imaging lens 12B, and the like is the same as that shown in FIG. 27, for example.

  The second area sensor 11 ′ has, for example, the configuration shown in FIG. Specifically, as illustrated in FIG. 28B, a plurality of imaging elements b are formed on the wafer a. Next, an image sensor as illustrated in FIG. 28B is cut out from the wafer a. The first image sensor 112 </ b> A and the second image sensor 112 </ b> B, which are a plurality of image sensors to be cut out, are formed on the silicon substrate 111. In contrast, the positions of the first imaging lens 12A and the second imaging lens 12B are determined in accordance with the interval between the first imaging element 112A and the second imaging element 112B.

  An image sensor is often manufactured for imaging. For this reason, the ratio between the X direction and the Y direction of the image sensor, that is, the aspect ratio, is often a ratio that matches the image format, such as square, “4: 3”, or “16: 9”. In the present embodiment, images at two or more points that are separated by a certain interval are captured. Specifically, an image is captured for each point that is spaced apart in the X direction, which is one direction in two dimensions, that is, in the transport direction 10 (FIG. 2). On the other hand, the image sensor has an aspect ratio that matches the image format. Therefore, in the case of imaging at two points that are separated by a certain interval in the X direction, the imaging element in the Y direction may not be used. Further, when the pixel density is increased, an image sensor having a high pixel density is used in either the X direction or the Y direction, which may increase the cost.

  Therefore, with the configuration shown in the drawing, the first image sensor 112A and the second image sensor 112B that are spaced apart from each other at a constant interval can be formed on the silicon substrate 111. Therefore, the number of image sensors that do not use the image sensor in the Y direction can be reduced. Therefore, waste of the image sensor can be reduced. Further, since the first image sensor 112A and the second image sensor 112B are formed by a highly accurate semiconductor process, the interval between the first image sensor 112A and the second image sensor 112B can be accurately performed.

  FIG. 29 is a schematic diagram illustrating an example of a plurality of imaging lenses used in a detection unit according to an embodiment of the present invention. A lens array as shown may be used to implement the detector.

  The illustrated lens array has a configuration in which two or more lenses are integrated. Specifically, the illustrated lens array is an example having three rows and three columns in the vertical and horizontal directions and a total of nine imaging lenses A1 to C3. When such a lens array is used, an image showing nine points can be taken. In this case, an area sensor having nine imaging areas is used.

  In this way, for example, calculations for two imaging regions are easily executed simultaneously, that is, executed in parallel. Next, when each calculation result is averaged or error elimination is performed, the detection apparatus can calculate with high accuracy or improve the stability of calculation compared to the case where one calculation result is used. can do. In some cases, the calculation is executed based on application software whose speed varies. Even in this case, since the area where the correlation calculation can be performed is widened, it is easy to obtain a speed calculation result with high accuracy.

  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. 30 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.

  The apparatus for ejecting liquid according to the present invention may be realized by a system for ejecting liquid having one or more apparatuses. 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.

  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, some or all of processing methods such as a method of causing a computer to discharge liquid, such as a transport device, a transport system having one or more information processing devices, or a combination thereof, are executed. It may be realized by a program for making it happen.

  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.

60 Conveyed object detection device 110 Image forming device 120 Web 210K Black liquid ejection head unit 210C Cyan liquid ejection head unit 210M Magenta liquid ejection head unit 210Y Yellow liquid ejection head unit SENK Black sensor SENC Cyan sensor SENM Magenta sensor SENY Yellow Sensor 520 controller

Japanese Patent Laying-Open No. 2015-13476

Claims (14)

An optical sensor for receiving the light reflected by the conveyed object;
Using the optical sensor, a detection result indicating a position, a moving speed, a moving amount, or a combination of these objects in at least one of a conveying direction in which the object is conveyed or a direction orthogonal to the conveying direction A detector that outputs
A transported object detection apparatus comprising: a setting unit that sets an aperture value and an exposure time related to the optical sensor based on the detection result. The transport object detection device according to claim 1, wherein the setting unit receives a speed at which the transport object is transported from outside. The transported object detection apparatus according to claim 1, wherein the setting unit sets the aperture value and the exposure time based on the moving speed.   The said detection part calculates | requires the said detection result based on the pattern which the said to-be-conveyed object has, The to-be-conveyed object detection apparatus of any one of Claim 1 thru | or 3 characterized by the above-mentioned. The pattern is generated by interference of light applied to the uneven shape formed on the transported object,
The said detection part calculates | requires the said detection result based on the image which imaged the said pattern, The to-be-conveyed object detection apparatus of Claim 4 characterized by the above-mentioned. The said detection part detects the said detection result based on the result which detected the said pattern at two or more different timings. The conveyed product detection apparatus of Claim 4 or 5 characterized by the above-mentioned. A transport apparatus comprising the transported object detection device according to any one of claims 1 to 6, having a head unit, and performing processing on the transported object by the head unit,
A transport apparatus comprising: a control unit that causes the head unit to perform the process based on the detection result of the transported object detection apparatus. The detector is
Provided in each of the head units; and
A first support member provided on the upstream side of the processing position where the head unit performs the processing on the object to be transported, and used for transporting the object to be transported;
8. The apparatus according to claim 7, wherein the head unit is provided between each of the head units, provided downstream of the processing position, and a second support member used for transporting the object to be transported. Transport device.   The transport device according to claim 8, wherein the detection unit is installed between the processing position and the first support member.   The transport apparatus according to claim 7, further comprising a moving unit that moves the head unit in the orthogonal direction.   The transport apparatus according to claim 7, wherein the head unit performs the processing on the transported object based on the detection result in the transport direction.   The transport apparatus according to claim 7, wherein the object to be transported is a continuous sheet that is long along the transport direction.   13. The transport apparatus according to claim 7, wherein an image is formed on the transported object when the processing is performed. A transported object detection method performed by a transported object detection device having an optical sensor that receives light reflected by a transported object,
The transported object detection device uses the optical sensor to position, travel speed, and travel of the transported object in at least one of a transport direction in which the transported object is transported or a direction orthogonal to the transport direction. Or a detection procedure for outputting a detection result indicating a combination thereof;
A setting procedure in which the conveyed object detection device sets an aperture value and an exposure time according to the optical sensor based on the detection result;
A method for detecting an object to be conveyed.

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