Image forming apparatus, control method for image forming apparatus, and program for controlling image forming apparatus

Abstract

To provide an image forming apparatus that can perform color adjustment without stopping sheet conveyance.SOLUTION: A method executed by an image forming apparatus includes: a step of acquiring a travel speed in the vertical direction relative to a sheet conveyance direction (S625); a step of arranging, as image for adjustment, trigger marks corresponding to the positions of patches for measurement performed by an arranged in-line sensor (S670); a step of acquiring an image forming condition and a measurement condition for color adjustment (S675); a step of forming the images for adjustment (patches and trigger marks) based on the acquired conditions (S680); a step of measuring the patches being the images for adjustment by an inline sensor to acquire a measured value (S685); and a step of calculating an adjustment value by using the acquired measured value (S690).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates to controlling an image forming device, and more particularly to adjusting color in an image forming device capable of printing color. [Background technology]

[0002] The color reproduction of output from image forming devices and other color-capable printers depends on the output environment, so color adjustments may be required under the output environment. For convenience, such color adjustments are made by measuring and adjusting colors using an in-line sensor (colorimeter) installed in the image forming device, rather than using an external colorimeter.

[0003] Regarding measurements using inline sensors, for example, Japanese Patent Laid-Open Publication No. 2016-48309 (Patent Document 1) discloses a technology that "calibrates one image detection unit with another image detection unit to improve image detection accuracy and reduce paper waste during calibration" (paragraph 0007). The technology disclosed in Patent Document 1 includes a "first image detection unit that detects an image on a transfer sheet on which an image is formed and being transported, and a second image detection unit that is separate from the first image detection unit and detects the image on the transfer sheet on which an image is formed and being transported, a detection unit calibration mode that calibrates the first image detection unit using the image detection results from the second image detection unit, and in the detection unit calibration mode, the transfer sheet transport speed during image reading by the second image detection unit is changed to a transfer sheet transport speed that is different from the normal transfer sheet transport speed during image formation, and a control unit that calibrates the first image detection unit based on the results of reading the same image by the first image detection unit and the second image detection unit, thereby improving the accuracy of the image detection unit without increasing paper waste during detection" (see [Abstract]).

[0004] However, measuring colors using an in-line sensor (colorimeter) takes a certain amount of time. Therefore, the normal paper transport speed of an image forming device cannot handle such measurements, and measuring color patches requires either stopping the paper transport or slowing it down. Therefore, there is a need for a method to measure color patches using an in-line sensor (colorimeter) without stopping or slowing down the paper transport.

[0005] For example, Japanese Patent Laid-Open Publication No. 2018-197775 (Patent Document 2) discloses an image forming apparatus that "appropriately performs colorimetry of an adjustment image using long paper." The image forming apparatus disclosed in Patent Document 2 "assumes a first conveying speed, which is a speed at which the transfer paper is conveyed when an image is formed and which is faster than a speed set for conveying the transfer paper when the image is read by the colorimetry unit, and a second conveying speed, which is slower than the first conveying speed and set as a speed at which the transfer paper is conveyed when the image is read by the colorimetry unit; in an adjustment mode in which the adjustment image is read using long paper as the transfer paper, the image forming unit and the conveying unit are controlled to form the adjustment image on the transfer paper conveyed at the second conveying speed, and the adjustment image formed on the transfer paper is read while the transfer paper is conveyed at the second conveying speed" (see [Abstract]). According to the technology disclosed in Patent Document 2, "even when a long sheet of paper is clamped and transported by both the image forming section and the colorimetric section, the transfer paper is transported at the same second transport speed for image formation and reading, making it possible to properly perform colorimetry of the adjustment image using the long sheet of paper" (paragraph 0023). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-48309 [Patent Document 2] Japanese Patent Application Publication No. 2018-197775 Summary of the Invention [Problem to be solved by the invention]

[0007] According to the technology disclosed in Patent Document 2, when the transfer paper is long, the colorimetric unit reads the image by extending the adjustment image in the sub-scanning direction without reducing the transfer paper transport speed. However, there is a need for a technology that can measure color even when the colorimetric unit moves in a direction perpendicular to the transfer paper transport direction.

[0008] The present disclosure has been made in consideration of the above-described background, and one of the purposes according to a certain aspect is to provide a technology that enables measurements to be made without stopping or slowing down the transport of paper when the colorimetric unit moves perpendicular to the transport direction of the paper. [Means for solving the problem]

[0009] An image forming apparatus according to one embodiment includes a transport mechanism for transporting a printing medium, an image forming unit for forming an image on the printing medium, an inline sensor that can move in a direction perpendicular to the transport direction of the printing medium to scan one or more color patches formed on the printing medium, and a control unit that controls the image forming unit to form one or more color patches on the printing medium in accordance with the transport speed of the printing medium and the movement speed of the inline sensor.

[0010] In one aspect, the color patches are arranged according to information on the print medium.

[0011] In one aspect, the information includes paper type and size.

[0012] In one aspect, the in-line sensor includes a spectrophotometer.

[0013] In one aspect, the in-line sensor further includes a trigger sensor.

[0014] In one aspect, the image forming apparatus further includes a trigger sensor that is provided separately from the in-line sensor.

[0015] In one aspect, the difference between the transport speed of the transport mechanism when forming one or more color patches on the printing medium and the transport speed when forming an image other than the one or more color patches on the printing medium is within a predetermined range.

[0016] In one aspect, the image forming unit further forms a trigger mark at a position that is predetermined relative to the position of the one or more color patches.

[0017] In one aspect, the placement of the trigger mark is determined according to the transport speed of the print medium and the movement speed of the in-line sensor.

[0018] In one aspect, the control unit performs color adjustment based on a signal output from the in-line sensor by scanning one or more color patches.

[0019] According to another embodiment, there is provided a method for controlling an image forming apparatus, the method including the steps of transporting a print medium, forming an image on the print medium, and moving an in-line sensor in a direction perpendicular to a transport direction of the print medium to scan one or more color patches formed on the print medium, the step of forming the image including forming the one or more color patches on the print medium in accordance with a transport speed of the print medium and a moving speed of the in-line sensor.

[0020] According to yet another embodiment, there is provided a program for controlling an image forming apparatus, the program causing the image forming apparatus to perform the steps of transporting a print medium, forming an image on the print medium, and moving an in-line sensor in a direction perpendicular to a transport direction of the print medium to scan one or more color patches formed on the print medium, the step of forming an image including forming the one or more color patches on the print medium in accordance with a transport speed of the print medium and a moving speed of the in-line sensor.

[0021] The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the invention taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram illustrating an external appearance of an image forming apparatus 100 according to an embodiment. [Figure 2] FIG. 10 is a diagram illustrating an external appearance of an image forming apparatus 200 according to another embodiment. [Figure 3] FIG. 2 is a block diagram showing an outline of the hardware configuration of image forming apparatuses 100 and 200. [Figure 4] FIG. 1 illustrates an example of the configuration of an in-line sensor 400 according to an aspect. [Figure 5] FIG. 10 is a diagram illustrating an example of the configuration of an in-line sensor 500 according to another aspect. [Figure 6] 10 is a flowchart showing a part of the process executed by a CPU 310 of the image forming apparatuses 100 and 200. [Figure 7] FIG. 7 shows one way in which patches are arranged on a long sheet of paper 700 when an inline sensor 400 is used. [Figure 8] FIG. 4 illustrates one way in which patches may be placed on a sheet when an in-line sensor 400 is used. [Figure 9] FIG. 9 shows one way in which patches are arranged on a long sheet of paper 900 when an inline sensor 500 is used. [Figure 10] 10A and 10B are diagrams showing other ways in which patches are arranged on the long sheet of paper 1000 when the inline sensor 400 is used. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. The names and functions of the components are also the same. Therefore, detailed description thereof will not be repeated.

[0024] An overview of an image forming apparatus according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a diagram showing the appearance of image forming apparatus 100 according to one embodiment. Figure 2 is a diagram showing the appearance of image forming apparatus 200 according to another embodiment. Image forming apparatus 200 can also handle printing on so-called long paper.

[0025] Referring to FIG. 1, image forming apparatus 100 includes a paper feed unit 110, an image forming unit 120, inline scanners 130 and 140, an inline sensor 150, a paper discharge unit 160, a conveyance unit 170, and a control unit 190.

[0026] The paper feed unit 110 receives a supply of paper or other printing media from an external source and supplies the printing media to the image forming unit 120 via a conveying unit 170.

[0027] Image forming unit 120 contains toner of each color, yellow (Y), magenta (M), cyan (C), and black (K). Image forming unit 120 forms an image on the print medium based on image data generated from data provided to image forming device 100.

[0028] The in-line scanners 130 and 140 optically read an image formed on a print medium by the image forming unit 120, and output a signal according to the read result. The output signal is input to the control unit 190.

[0029] The in-line sensor 150 detects color patches arranged on the print medium, and the detection results are sent to the control unit 190.

[0030] The paper discharge unit 160 receives the print medium on which an image is formed and is discharged. The paper discharge unit 160 may be configured to receive the discarded paper in a different cassette for each job.

[0031] The transport unit 170 operates in response to commands from the control unit 190 and transports the print medium from the paper feed unit 110 to the paper discharge unit 160 .

[0032] Controller 190 controls the operation of image forming apparatus 100. In one aspect, controller 190 is implemented by one or more processors that execute instructions.

[0033] 2, image forming apparatus 200 includes paper feed unit 110, image forming unit 120, inline scanners 130 and 140, inline sensor 150, paper discharge unit 160, conveyance unit 170, and control unit 190. Paper feed unit 110 includes paper feed roller 210. Paper discharge unit 160 includes paper discharge roller 220.

[0034] The paper feed unit 110, image forming unit 120, inline scanners 130 and 140, inline sensor 150, paper discharge unit 160, and control unit 190 of image forming apparatus 200 realize functions similar to those realized by the paper feed unit 110, image forming unit 120, inline scanners 130 and 140, inline sensor 150, paper discharge unit 160, and control unit 190 of image forming apparatus 100, respectively.

[0035] Furthermore, a roll of long paper prepared as a print medium is loaded onto the paper feed roller 210. The long paper is sequentially fed out by the transport unit 170 and taken up by the paper discharge roller 220.

[0036] The specific configuration of the image forming apparatuses 100 and 200 will be described with reference to Fig. 3. Fig. 3 is a block diagram showing an outline of the hardware configuration of the image forming apparatuses 100 and 200. The image forming apparatuses 100 and 200 include a CPU (Central Processing Unit) 310, a RAM 320, a storage unit 330, an operation unit 340, a display unit 350, a communication unit 360, an image forming unit 120, and an image reading unit 370. The image reading unit 370 includes inline scanners 130 and 140 and an inline sensor 150.

[0037] The CPU 310 controls the operations of the image forming apparatuses 100 and 200. The RAM 320 temporarily stores data that the image forming apparatuses 100 and 200 receive from the outside or data that the CPU 310 generates.

[0038] Storage unit 330 permanently stores data received by image forming apparatuses 100 and 200 from an external device or data generated by CPU 310. In one aspect, storage unit 330 is implemented by a non-volatile storage device such as a hard disk drive or a solid state drive (SSD). In one aspect, storage unit 330 stores various programs including a color adjustment patch creation program, a color adjustment execution program, an inline sensor measurement program, and a color adjustment calculation program.

[0039] Operation unit 340 accepts commands input by a user of image forming apparatus 100, 200. In one aspect, operation unit 340 is implemented as a software switch such as a touch panel, or as a hardware switch such as a button or a toggle switch. In another aspect, operation unit 340 may be configured as a detachable operation panel, such as in a tablet terminal.

[0040] Display unit 350 displays an operation screen or status of image forming apparatus 100, 200. The operation screen displays operating conditions, including color adjustment, density, and other printing conditions, input by a user of image forming apparatus 100, 200. The status of image forming apparatus 100, 200 includes information indicating the current status of image forming apparatus 100, 200. In one aspect, display unit 350 is implemented as a liquid crystal monitor or an organic electroluminescence (EL) monitor. In another aspect, display unit 350 can be implemented as a detachable monitor device, such as a tablet terminal.

[0041] Communication unit 360 communicates with a personal computer or other information and communication device that can communicate with image forming apparatus 100, 200. The communication format is not particularly limited. The information and communication device transmits a print command to image forming apparatus 100, 200, and upon receiving the print command, image forming apparatus 100, 200 executes a predetermined printing operation. In another aspect, the information and communication device can also function as an external monitor device that displays the status of image forming apparatus 100, 200.

[0042] Image reading unit 370 measures patches placed on print media to adjust colors and check accuracy. In one aspect, inline sensor 150 reads patches formed on color-printed paper and outputs a signal corresponding to the reading result. This signal is input to CPU 310. CPU 310 uses this signal to adjust each color or check accuracy.

[0043] 4 and 5, a specific configuration of the inline sensor 150 will be described. The inline sensor 150 can move in a direction perpendicular to the paper transport direction. The inline sensor 150 measures color patches arranged on the paper in the main scanning direction.

[0044] Fig. 4 is a diagram illustrating an example of the configuration of an in-line sensor 400 according to one aspect. Fig. 5 is a diagram illustrating an example of the configuration of an in-line sensor 500 according to another aspect.

[0045] 4, in-line sensor 400 includes a colorimeter 410 and a trigger sensor 420. Colorimeter 410 performs spectroscopic measurements to obtain color values ​​(L*a*b, XYZ, density) similar to those obtained by an external colorimeter. Trigger sensor 420 detects a trigger mark that serves as the measurement reference point for in-line sensor 400. Trigger sensor 420 moves in the same manner as colorimeter 410, and therefore can detect trigger marks arranged in the main scanning direction.

[0046] 5, in-line sensor 500 includes colorimeter 410. Trigger sensor 420 is disposed separately from in-line sensor 500. With this configuration, colorimeter 410 moves in a direction perpendicular to the paper transport direction and can measure color patches arranged in the main scanning direction on the paper. On the other hand, trigger sensor 420 is fixed to image forming apparatus 100, 200 and does not move, so it detects trigger marks arranged at predetermined positions on the paper in the main scanning direction.

[0047] [Control Structure] The control structure of image forming apparatuses 100 and 200 will be described with reference to Fig. 6. Fig. 6 is a flowchart showing a part of the processing executed by CPU 310 of image forming apparatuses 100 and 200. Note that in another aspect, this processing may be realized by circuit elements or other hardware.

[0048] In step S610, CPU 310 detects that a color adjustment instruction has been received based on a setting input provided to operation unit 340. For example, when a user of image forming apparatus 100, 200 inputs an instruction to perform color adjustment, CPU 310 starts the color adjustment operation. The color adjustment instruction is given, for example, when image forming apparatus 100, 200 starts operation, or when image forming apparatus 100, 200 finishes printing one content and starts printing another content. In another aspect, CPU 310 can be configured to automatically perform color adjustment at a preset timing.

[0049] In step S615, CPU 310 acquires the colors to be adjusted and the number of colors based on the setting input. For example, when a color printing instruction is input, CPU 310 may set yellow, magenta, cyan, and black as the colors to be adjusted. In another aspect, CPU 310 may select the colors specified by the user as the colors to be adjusted.

[0050] In step S620, CPU 310 acquires the paper transport speed of the output conditions. For example, CPU 310 selects a speed corresponding to the selected print quality from multiple paper transport speeds prepared in advance according to the print quality. The multiple paper transport speeds are stored in storage unit 330 or RAM 320.

[0051] In step S625, CPU 310 acquires the movement speed of inline sensors 400 and 500 in a direction perpendicular to the paper transport direction. That is, CPU 310 calculates the speed at which inline sensors 400 and 500 move across paper as the print medium while it is being transported. This speed is set at least as fast as possible for inline sensor 150 to scan across the area to be printed on the paper while the paper is being transported at the normal printing speed. In one aspect, this movement speed is set to ensure the shortest time possible for inline sensors 400 and 500 to manipulate color.

[0052] In step S630, CPU 310 calculates a rule for arranging patches in the main scanning direction for measurement by inline sensors 400 and 500. For example, CPU 310 determines whether to arrange the patches in a line or to arrange them diagonally across the printable area of ​​the paper.

[0053] In step S635, CPU 310 determines whether the paper type is long paper. This determination is made based on instructions provided by the user of image forming apparatuses 100, 200, or the type of paper feed mechanism installed in paper feed unit 110 (a cassette for sheets or a paper feed roller). If CPU 310 determines that the paper type is long paper (YES in step S635), it switches control to step S640. If not (NO in step S635), CPU 310 switches control to step S645.

[0054] In step S640, CPU 310 acquires the size of the paper. For example, CPU 310 acquires width information of the roll paper set on paper feed roller 210 from a sensor (not shown) of paper feed unit 110. In another aspect, CPU 310 acquires the size (width information) of the paper being conveyed based on the information about long paper set on operation unit 340.

[0055] In step S645, CPU 310 acquires the size of the paper being conveyed. For example, CPU 310 acquires the size of the paper being conveyed based on the type of paper cassette used in paper feed unit 110 or based on paper information set in operation unit 340.

[0056] In step S650, CPU 310 calculates the number of patches that can be arranged on one sheet of paper.

[0057] In step S655, CPU 310 determines whether the adjusted colors can be arranged on one sheet of paper. If CPU 310 determines that the adjusted colors can be arranged on one sheet of paper (YES in step S655), CPU 310 switches control to step S660.

[0058] In step S660, CPU 310 determines the placement of patches in the main scanning direction for measurement by inline sensors 400, 500. For example, in the case of long paper, if the length of one printed sheet (feed amount in the transport direction) is 5 m and the width of the long paper is 1 m, CPU 310 calculates how many scans inline sensors 400, 500 can perform based on the distance of the long paper in the scanning direction (= 1 m) and the operating capacity of inline sensors 400, 500. For example, if CPU 310 determines that 10 scans are possible, it may divide the printing area (e.g., 4.5 m) of the length in the transport direction (= 5 m) into 10 equal parts and calculate the placement interval of each color patch as 0.45 m. On the other hand, when image forming apparatus 100 transports a sheet of paper as a print medium, if CPU 310 determines, based on the width of the sheet and the scanning speed of inline sensors 400 and 500, that inline sensors 400 and 500 can scan eight times while one sheet of paper is transported, CPU 310 may determine that eight measurement patches (color patches) can be arranged in the scanning direction. In this case, CPU 310 may divide the length of one sheet of paper in the transport direction into eight equal parts, and determine the position of each patch so that the eight patches are equally spaced.

[0059] In step S665, CPU 310 divides the pages and determines the layout of patches in the main scanning direction for measurement by inline sensors 400 and 500. For example, if color adjustment is performed for each of multiple colors, CPU 310 may determine to arrange patches for each color on one sheet of paper.

[0060] In step S670, CPU 310 arranges trigger marks corresponding to the positions of patches for measurement by arranged inline sensors 400 and 500 as adjustment images.

[0061] In step S675, CPU 310 acquires image formation conditions and measurement conditions for color adjustment. The image formation conditions are the profile type, which is a color management condition, or the spot color table type if the adjusted color is a special color. The measurement conditions include the setting of light source conditions (M0, M1, M2), etc.

[0062] In step S680, CPU 310 forms an adjustment image (each patch and trigger mark) on paper based on the acquired conditions.

[0063] In step S685, CPU 310 measures the patch of the adjustment image with in-line sensors 400 and 500 and acquires the measurement values.

[0064] In step S690, CPU 310 calculates an adjustment value using the acquired measurement value.

[0065] In step S695, CPU 310 registers the adjustment values. For example, CPU 310 registers the adjustment values ​​in RAM 320 or storage unit 330. Thereafter, printing by image forming apparatuses 100 and 200 is performed with the registered adjustment values ​​reflected.

[0066] [Example of an image for adjustment] An example of an adjustment image will be described with reference to Figures 7 and 8. Figure 7 is a diagram showing one manner in which patches are arranged on a long sheet of paper 700 when an inline sensor 400 is used. Figure 8 is a diagram showing one manner in which patches are arranged on a sheet of paper when an inline sensor 400 is used.

[0067] 7, long sheet of paper 700 is transported in the direction of arrow 720. Inline sensor 400 moves in the directions of arrows 710 and 711. That is, inline sensor 400 moves back and forth in a direction perpendicular to the direction in which long sheet of paper 700 is transported.

[0068] In one aspect, the image forming unit 120 forms a plurality of trigger marks 730, a plurality of first color patches 740, and a plurality of second color patches 750 on the long sheet of paper 700. In the example shown in Figure 7, the trigger marks 730 and the first color patches 740 are formed in eight locations across the long sheet of paper 700.

[0069] While the long sheet of paper 700 is being transported in the direction of arrow 720, the in-line sensor 400 moves in the direction of arrow 710 at a predetermined speed. This speed is set, for example, so that the in-line sensor 400 can measure the first color patches 740 formed in eight locations while it travels from the left edge to the right edge of the long sheet of paper 700. When the in-line sensor 400 detects the first trigger mark 730, it assumes that a color patch will appear after that and waits in measurement mode.

[0070] The inline sensor 400 measures the color of the first first color patch 740. The measurement value is input to the CPU 310. The inline sensor 400 continues to move according to the transport speed of the long sheet 700, and when it detects the second trigger mark 730, it waits to measure the second first color patch 740. When the inline sensor 400 detects the second first color patch 740, it outputs the measurement value. The inline sensor 400 measures the color of the first color patches at eight locations while moving in the direction of the arrow 710.

[0071] When in-line sensor 400 detects trigger mark 760, it outputs a signal indicating the detection to CPU 310. CPU 310 detects that in-line sensor 400 has finished scanning in the first scanning direction (the direction of arrow 710).

[0072] When inline sensor 400 detects trigger mark 761, it detects the start of scanning in the second scanning direction (the direction of arrow 711). More specifically, when inline sensor 400 detects trigger mark 730, it waits for the detection of an adjustment image. When inline sensor 400 detects second color patch 750 arranged in a first location, it measures the color of second color patch 750 and outputs the measurement value to CPU 310. Thereafter, inline sensor 400 detects trigger mark 730 arranged in a second location and further measures the color of second color patch 750. While moving in the direction of arrow 711, inline sensor 400 measures the colors of second color patches 750 arranged in eight locations and outputs the measurement value to CPU 310.

[0073] Thereafter, when inline sensor 400 detects trigger mark 770, it outputs a signal according to the detection result to CPU 310. CPU 310 detects that measurement of second color patch 750 in the second scanning direction (the direction of arrow 720) has ended. Based on the measurement value and color information based on preset information, CPU 310 determines whether the color of the image formed on long sheet 700 is the specified color. CPU 310 can adjust the color according to the result of this determination.

[0074] When the in-line sensor 400 detects the trigger mark 772 following the trigger mark 771, it detects that scanning for image adjustment of the long sheet 700 has ended.

[0075] In another aspect, there may be a case where the trigger mark 772 is not formed on the long sheet of paper 700, and the third color patch is formed in the same manner as the first color patch 740. In this case, the third color patch is assumed to be arranged in the same manner as the first color patch 740, and the inline sensor 400 may again move in the direction of the arrow 710 to measure the third color patch.

[0076] 8, color adjustment using in-line sensor 400 can also be applied to sheets. Specifically, similar to the example illustrated in FIG. 7, sheets are sequentially transported in the direction of arrow 720. In-line sensor 400 moves in the directions of arrows 710 and 711.

[0077] The first sheet 810 has trigger marks 730 and first color patches 740 formed in eight locations. Trigger marks 760 and 761 are also arranged on the first sheet 810. The second sheet 820 has trigger marks 730 and second color patches 750 formed in eight locations. Trigger marks 770, 771, and 772 are also arranged on the second sheet 820.

[0078] While the first sheet 810 is being transported in the direction of arrow 720, the in-line sensor 400 moves in the direction of arrow 710 at a predetermined speed. This speed is set, for example, so that the in-line sensor 400 can measure the first color patches 740 formed in eight locations while it travels from the left edge to the right edge of the sheet 810. When the in-line sensor 400 detects the first trigger mark 730, it assumes that the first color patch 740 will appear thereafter, and waits in measurement mode.

[0079] The inline sensor 400 measures the color of the first color patch 740 in a first location and outputs the measurement value. The measurement value is input to the CPU 310. The inline sensor 400 continues to move in accordance with the conveyance speed of the paper sheet 810, and when it detects the second trigger mark 730, it waits to measure the second first color patch 740. When the inline sensor 400 detects the second first color patch 740, it outputs the measurement value. In this way, the inline sensor 400 measures the color of the first color patches in eight locations while moving in the direction of the arrow 710.

[0080] When in-line sensor 400 detects trigger mark 760, it outputs a signal indicating the detection to CPU 310. CPU 310 detects that scanning in the first scanning direction (the direction of arrow 710) has ended.

[0081] When inline sensor 400 detects trigger mark 761, it detects that scanning of the second sheet 820 in the second scanning direction (the direction of arrow 711) has begun. More specifically, when inline sensor 400 detects trigger mark 730, it waits for detection of an adjustment image. When inline sensor 400 detects second color patch 750 arranged in a first location, it measures the color of second color patch 750 and outputs the measurement value to CPU 310. Thereafter, inline sensor 400 detects trigger mark 730 arranged in a second location and further measures the color of second color patch 750. While moving in the direction of arrow 711, inline sensor 400 measures the colors of second color patches 750 arranged in eight locations and outputs the measurement value to CPU 310.

[0082] Thereafter, when in-line sensor 400 detects trigger mark 770, it outputs a signal corresponding to the detection result to CPU 310. CPU 310 detects that measurement of second color patch 750 in the second scanning direction (the direction of arrow 720) has ended. CPU 310 determines whether the color of the image formed on sheet 820 is the specified color based on the measurement value and color information based on preset information. CPU 310 may adjust the color according to the result of this determination.

[0083] When the in-line sensor 400 detects the trigger mark 772 following the trigger mark 771, it detects that the image adjustment for all colors has been completed.

[0084] [Other examples of images for adjustment] Another example of the adjustment image will be described with reference to Fig. 9. Fig. 9 is a diagram showing one mode in which patches are arranged on long paper 900 when inline sensor 500 is used.

[0085] 9, long sheet 900 is transported in the direction of arrow 720. Inline sensor 500 moves in the directions of arrows 710 and 711. That is, inline sensor 500 moves back and forth in a direction perpendicular to the direction in which long sheet 900 is transported.

[0086] In one aspect, the image forming unit 120 forms a plurality of trigger marks 730, a plurality of first color patches 740, and a plurality of second color patches 750 on the long sheet of paper 700. In the example shown in FIG. 9, the trigger marks 730 and the first color patches 740 are formed in eight locations across the long sheet of paper 900. In this case, the trigger marks 730 are arranged in a line along the transport direction of the long sheet of paper 900. The trigger marks 730 are arranged at equal intervals, for example.

[0087] When inline sensor 500 detects the first trigger mark 730, it outputs the detection result. The detection result is transmitted to CPU 310. CPU 310 sets the operation mode of image forming apparatuses 100 and 200 to the color adjustment mode, and waits for the reception of a subsequent signal.

[0088] When the inline sensor 500 detects the first color patch 740 at the first location, it measures the color of the first color patch 740 and outputs the measurement value. The measurement value is input to the CPU 310.

[0089] While the long sheet of paper 900 is being transported in the direction of arrow 720, the in-line sensor 500 moves in the direction of arrow 710 at a predetermined speed. This speed is set, for example, so that the in-line sensor 500 can measure the first color patches 740 formed in eight locations while it travels from the left end to the right end of the long sheet of paper 900.

[0090] The inline sensor 500 measures the color of the first first color patch 740. The measurement value is input to the CPU 310. The inline sensor 500 continues to move according to the transport speed of the long sheet 900, and when it detects the second trigger mark 730, it waits to measure the second first color patch 740. When the inline sensor 500 detects the second first color patch 740, it outputs the measurement value. The inline sensor 500 measures the color of the first color patches at eight locations while moving in the direction of the arrow 710.

[0091] If trigger sensor 420 does not detect the next trigger mark 730 within a set period after detecting trigger mark 730, it outputs a signal indicating this to CPU 310. CPU 310 detects that in-line sensor 500 has finished scanning in the first scanning direction (the direction of arrow 710).

[0092] After detecting that scanning in the first scanning direction (the direction of arrow 710) has ended, in-line sensor 500 waits for scanning in the second scanning direction (the direction of arrow 711).

[0093] When trigger sensor 420 detects the first trigger mark 730 (ninth from the top in FIG. 9 ) for scanning in the second scanning direction (the direction of arrow 711), it outputs the detection result. The detection result is sent to CPU 310. CPU 310 sends a signal to inline sensor 500 to start scanning in the second scanning direction (the direction of arrow 711). More specifically, when inline sensor 500 detects second color patch 750 arranged in the first location, it measures the color of second color patch 750 and outputs the measurement value. The measurement value is input to CPU 310.

[0094] Thereafter, the inline sensor 500 detects the trigger mark 730 placed in the second location, and further measures the color of the second color patch 750. While moving in the direction of the arrow 711, the inline sensor 500 sequentially measures the color of the second color patches 750 placed in eight locations, and outputs each measurement value. Each measurement value is input to the CPU 310.

[0095] Thereafter, if trigger sensor 420 does not detect the next trigger mark 730 within a set period after detecting trigger mark 730, it outputs a signal indicating this to CPU 310. CPU 310 detects that measurement of second color patch 750 in the second scanning direction (the direction of arrow 720) has ended. CPU 310 determines whether the color of the image formed on long sheet 900 is the specified color based on the measurement values ​​acquired so far and color information based on preset information. CPU 310 can adjust the color depending on the result of this determination.

[0096] After CPU 310 detects the end of measurement of second color patch 750 in the second scanning direction (the direction of arrow 720), if trigger sensor 420 does not detect the next trigger mark 730 within a set period, a signal indicating this is output to CPU 310. CPU 310 detects that image adjustment of long paper 900 has ended.

[0097] In another aspect, after CPU 310 detects the end of measurement of second color patch 750 in the second scanning direction (the direction of arrow 720), when trigger sensor 420 detects the next trigger mark 730 within a set period, it may be the case that a third color patch is formed in the same manner as first color patch 740. In this case, assuming that the third color patch is arranged in the same manner as first color patch 740, inline sensor 500 may again move in the direction of arrow 710 and measure the third color patch.

[0098] Another example will be described with reference to Figure 10. Figure 10 is a diagram showing another manner in which patches are arranged on long sheet of paper 1000 when an inline sensor 400 is used. The example shown in Figure 10 is an example in which an inline scanner 140 is used as one of the trigger sensors, and trigger marks 730 arranged on both ends of the long sheet of paper 1000 are detected by the inline scanner 140, and is different from the example shown in Figure 7. Note that the trigger marks 730 are also used to adjust the position of the paper.

[0099] The long sheet of paper 1000 is transported in the direction of arrow 720. The inline sensor 400 moves in the directions of arrows 710 and 711. That is, similar to the example shown in Figure 7, the inline sensor 400 moves back and forth in a direction perpendicular to the direction in which the long sheet of paper 1000 is transported.

[0100] In one aspect, the image forming unit 120 forms two trigger marks 730, a plurality of first color patches 740, and a plurality of second color patches 750 on the long sheet of paper 1000. In the example shown in Figure 10, the two trigger marks 730 are formed on both ends of the long sheet of paper. The first color patches 740 are formed in eight locations across the long sheet of paper 1000.

[0101] While the long sheet 1000 is being transported in the direction of arrow 720, the inline sensor 400 moves in the direction of arrow 710 at a predetermined speed. This speed is set, for example, so that the inline sensor 400 can measure the first color patches 740 formed in eight locations while traveling from the left edge to the right edge of the long sheet 1000. When the inline scanner 140 detects the first trigger mark 730, it outputs the detection result. The detection result is input to the CPU 310. The CPU 310 assumes that a color patch will appear after that, notifies the inline sensor 400, and waits in measurement mode.

[0102] The inline sensor 400 measures the color of the first color patch 740 in a first location and outputs the measurement value. The measurement value is input to the CPU 310. The inline sensor 400 continues to move according to the transport speed of the long sheet 700. When the inline sensor 400 detects the second first color patch 740, it outputs the measurement value. The measurement value is input to the CPU 310. In this way, the inline sensor 400 measures the color of the first color patches in eight locations while moving in the direction of the arrow 710.

[0103] When inline sensor 400 detects trigger mark 760, it outputs a signal indicating the detection. This signal is input to CPU 310. Based on this signal, CPU 310 detects that inline sensor 400 has finished scanning in the first scanning direction (the direction of arrow 710). The movement of inline sensor 400 ends based on the detection of trigger mark 760. The transport of long sheet 1000 continues. When inline sensor 400 detects trigger mark 761, it outputs the detection result. The detection result is input to CPU 310. Based on the detection result, CPU 310 detects the start of scanning in the direction of arrow 711.

[0104] More specifically, when inline sensor 400 detects second color patch 750 arranged in a first location, it measures the color of second color patch 750 and outputs the measurement value. The measurement value is input to CPU 310. Thereafter, when inline sensor 400 detects second color patch 750 arranged in a second location, it measures the color of second color patch 750. While moving in the direction of arrow 711, inline sensor 400 sequentially measures the colors of second color patches 750 arranged in eight locations and outputs each measurement value to CPU 310.

[0105] Thereafter, when the inline sensor 400 detects the trigger mark 770, it outputs a signal according to the detection result. The signal is input to the CPU 310. Based on the reception of the signal, the CPU 310 detects that the measurement of the second color patch 750 in the second scanning direction (the direction of the arrow 720) has ended. Based on the measurement value and color information based on preset information, the CPU 310 determines whether the color of the image formed on the long sheet 1000 is the specified color. The CPU 310 can adjust the color according to the result of this determination.

[0106] When the in-line sensor 400 detects the trigger mark 772 following the trigger mark 771, it detects that the scanning for image adjustment of the long sheet 1000 has ended.

[0107] In another aspect, there may be a case where the trigger mark 772 is not formed on the long sheet of paper 700, and the third color patch is formed in the same manner as the first color patch 740. In this case, the third color patch is assumed to be arranged in the same manner as the first color patch 740, and the inline sensor 400 may again move in the direction of the arrow 710 to measure the third color patch.

[0108] The technical features disclosed above can be summarized as follows:

[0109] [Configuration 1] An image forming apparatus 100, 200 according to one embodiment includes a transport mechanism (transport unit 170) that transports a print medium, an image forming unit 120 that forms an image on the print medium, an inline sensor 150 that can move in a direction perpendicular to the transport direction of the print medium to scan one or more color patches formed on the print medium, and a control unit (CPU 310) that controls the image forming unit to form one or more color patches on the print medium in accordance with the transport speed of the print medium and the movement speed of the inline sensor.

[0110] [Configuration 2] In one aspect, the color patches are arranged according to information about the printing medium (e.g., the width of a long sheet of paper, the printing length of one sheet, the size of the sheet, etc.). The CPU 310 determines the locations of the color patches based on this information. This information is provided as image formation data before printing begins.

[0111] [Configuration 3] In one aspect, the information includes the type and size of paper.

[0112] [Configuration 4] In one aspect, the in-line sensor includes a spectrophotometer.

[0113] [Configuration 5] In one aspect, the in-line sensor further includes a trigger sensor. Since the spectrophotometer and the trigger sensor can move together, the CPU 310 can form the color patch and the trigger patch in close proximity to each other.

[0114] [Configuration 6] In one aspect, the image forming apparatus further includes a trigger sensor that is provided separately from the in-line sensor. Since the trigger sensor is provided independently of the movement of the in-line sensor, trigger marks 730 can be formed at locations away from the positions of the color patches.

[0115] [Configuration 7] In one aspect, the difference between the transport speed of the transport mechanism when forming one or more color patches on the print medium and the transport speed when forming an image other than the one or more color patches on the print medium is within a predetermined range. The predetermined range is such that there is essentially no speed difference. Since there is no need to change the speed at which the print medium is transported to print a content image on the print medium and the speed at which the print medium is transported to print color patches for color adjustment on the print medium, there is no need to complicate the transport control of image forming apparatuses 100 and 200.

[0116] [Configuration 8] In one aspect, the image forming unit further forms a trigger mark at a position that is predetermined relative to the position of the one or more color patches.

[0117] [Configuration 9] In one aspect, the placement of the trigger mark is determined according to the transport speed of the print medium and the movement speed of the in-line sensor 150.

[0118] [Configuration 10] In one aspect, the control unit performs color adjustment based on a signal output from an in-line sensor by scanning one or more color patches. For example, if the color values ​​obtained by reading the image (color patch) actually formed on the print medium differ from the color values ​​given as an image formation instruction, the CPU 310 corrects the color values ​​based on the difference between these values.

[0119] [Configuration 11] According to another embodiment, a control method for an image forming apparatus is provided. This control method is realized, for example, by CPU 310 of image forming apparatus 100, 200. Specifically, the control method includes the steps of transporting a print medium, forming an image on the print medium, and moving an in-line sensor in a direction perpendicular to the transport direction of the print medium to scan one or more color patches formed on the print medium. The step of forming the image includes forming one or more color patches on the print medium in accordance with the transport speed of the print medium and the movement speed of the in-line sensor.

[0120] [Configuration 12] According to yet another embodiment, a program for controlling an image forming apparatus is provided. The program causes the image forming apparatus to carry out the steps of transporting a print medium, forming an image on the print medium, and moving an in-line sensor in a direction perpendicular to the print medium transport direction to scan one or more color patches formed on the print medium. The step of forming an image includes forming one or more color patches on the print medium in accordance with the print medium transport speed and the in-line sensor movement speed. For example, CPU 310 can execute each of the above processing steps by loading the program stored in storage unit 330 into RAM 320 and executing instructions included in the program.

[0121] As described above, in the image forming apparatuses 100 and 200 according to the present embodiment, the in-line sensors 400 and 500, which are color measurement units, move in a direction perpendicular to the paper transport direction to measure color patches formed on the paper. This allows the in-line sensors 400 and 500 to measure patches arranged in the main scanning direction without temporarily stopping or slowing down the paper transport.

[0122] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Industrial Applicability]

[0123] The disclosed technical features are applicable to commercial printing machines, for example, both sheet-fed printing machines and long paper (roll paper) printing machines. [Explanation of symbols]

[0124] 100, 200 image forming device, 110 paper feed unit, 120 image forming unit, 130, 140 inline scanner, 150, 400, 500 inline sensor, 160 paper discharge unit, 170 transport unit, 190 control unit, 210 paper feed roller, 220 paper discharge roller, 320 RAM, 330 memory unit, 340 operation unit, 350 display unit, 360 communication unit, 370 image reading unit, 410 colorimeter, 420 trigger sensor, 700, 900, 1000 long paper, 710, 711, 720 arrow, 722, 730, 760, 761, 770, 771, 772 trigger mark, 740 first color patch, 750 second color patch, 810, 820 sheet of paper.

Claims

1. a transport mechanism for transporting the print medium; an image forming unit that forms an image on the print medium; an in-line sensor movable in a first scanning direction perpendicular to a transport direction of the print medium or in a second scanning direction opposite to the first scanning direction to scan one or more color patches formed on the print medium; a control unit that controls the image forming unit to form the one or more color patches on the printing medium in accordance with a conveyance speed of the printing medium and a movement speed of the in-line sensor; a trigger sensor that detects a trigger mark and outputs the detection result to the control unit; the one or more color patches include a first color patch that is scanned last before switching from the first scanning direction to the second scanning direction, and a second color patch that is scanned first after the switching, the image forming unit forms a first trigger mark and a second trigger mark between the first color patch and the second color patch along the transport direction; the trigger sensor detects that scanning in the first scanning direction has ended in response to detecting the first trigger mark; The image forming apparatus, wherein the trigger sensor detects the start of scanning in the second scanning direction in response to detecting the second trigger mark.

2. The image forming apparatus according to claim 1 , wherein the color patches are arranged in accordance with information on the print medium.

3. The image forming apparatus according to claim 2 , wherein the information includes a type and a size of the paper.

4. 4. The image forming apparatus according to claim 1, wherein the in-line sensor includes a spectrophotometer.

5. An image forming apparatus as described in Claim 4, wherein the trigger sensor is included in the inline sensor.

6. An image forming apparatus as described in Claim 4, wherein the trigger sensor is provided separately from the inline sensor.

7. An image forming apparatus as described in any one of claims 1 to 6, wherein the difference between the transport speed of the transport mechanism when forming the one or more color patches on the printing medium and the transport speed when forming an image other than the one or more color patches on the printing medium is within a predetermined range.

8. 8. The image forming apparatus according to claim 1, wherein the image forming section further forms a third trigger mark at a predetermined position relative to the position of the one or more color patches.

9. the placement of the third trigger mark is determined in accordance with the transport speed of the print medium and the movement speed of the in-line sensor; The image forming apparatus according to claim 8 , wherein the trigger sensor waits in a measurement mode in response to detecting the third trigger mark.

10. 10. The image forming apparatus according to claim 1, wherein the control unit performs color adjustment based on a signal output from the in-line sensor by scanning the one or more color patches.

11. A control method for an image forming apparatus, comprising: transporting a print medium; forming an image on the print medium; and moving an in-line sensor in a first scanning direction perpendicular to a transport direction of the print medium or in a second scanning direction opposite to the first scanning direction to scan one or more color patches formed on the print medium; the step of forming the image includes a step of forming the one or more color patches on the print medium in accordance with a transport speed of the print medium and a movement speed of the in-line sensor; the one or more color patches include a first color patch that is scanned last before switching from the first scanning direction to the second scanning direction, and a second color patch that is scanned first after the switching, the step of forming the image further includes the step of forming a first trigger mark and a second trigger mark between the first color patch and the second color patch along the transport direction, The control method includes a step of detecting that scanning in the first scanning direction has ended in response to a trigger sensor detecting the first trigger mark; detecting, in response to the trigger sensor detecting the second trigger mark, that scanning in the second scanning direction is to be started.

12. A program for controlling an image forming apparatus, the program including: transporting a print medium; forming an image on the print medium; and moving an in-line sensor in a first scanning direction perpendicular to a transport direction of the print medium or in a second scanning direction opposite to the first scanning direction to scan one or more color patches formed on the print medium; the step of forming the image includes a step of forming the one or more color patches on the print medium in accordance with a transport speed of the print medium and a movement speed of the in-line sensor; the one or more color patches include a first color patch that is scanned last before switching from the first scanning direction to the second scanning direction, and a second color patch that is scanned first after the switching, the step of forming the image further includes the step of forming a first trigger mark and a second trigger mark between the first color patch and the second color patch along the transport direction, the program includes a step of detecting that scanning in the first scanning direction has ended in response to a trigger sensor detecting the first trigger mark; detecting, in response to the trigger sensor detecting the second trigger mark, that scanning in the second scanning direction is to be started.

Images