阅读说明：本技术 图像检查装置以及程序 (Image inspection device and program ) 是由 黑畑贵夫 于 2019-08-19 设计创作，主要内容包括：在记录介质有倾斜的情况下,能够正常地进行图像的正常、异常的检查。图像检查装置具有：检查控制部,获取对进行了图像形成的记录介质的图像进行读取而获得的读取图像,并从读取图像以某个单位划分检查区域来准备比较图像,并基于比较图像来判定图像的正常/异常；以及倾斜检测部,检测由记录介质的蜿蜒而行引起的倾斜状态,检查控制部接受来自倾斜检测部的检测信息,并根据检测信息使检查区域的图像倾斜来实施图像的正常/异常的判定。(When the recording medium is tilted, the image can be normally inspected for normality or abnormality. The image inspection apparatus includes: an inspection control unit that acquires a read image obtained by reading an image of a recording medium on which an image has been formed, divides an inspection area from the read image by a certain unit to prepare a comparison image, and determines normality/abnormality of the image based on the comparison image; and a tilt detection unit that detects a tilt state caused by the wriggling of the recording medium, wherein the inspection control unit receives detection information from the tilt detection unit and tilts the image of the inspection area based on the detection information to determine whether the image is normal or abnormal.)

1. An image inspection apparatus, comprising:

an inspection control unit that acquires a read image obtained by reading an image of a recording medium on which an image has been formed, divides an inspection area by a certain unit from the read image to prepare a comparison image, and determines whether the image is normal or abnormal based on the comparison image; and

a tilt detecting unit for detecting a tilt state caused by the wriggling of the recording medium,

the inspection control unit receives detection information from the inclination detection unit, and performs image normality/abnormality determination by inclining the image of the inspection area based on the detection information.

2. The image inspection apparatus according to claim 1,

the inspection control unit divides the image into a plurality of units and then tilts the image of the inspection area based on the detection information from the tilt detection unit as a comparison image.

3. The image inspection apparatus according to claim 1,

the inspection control unit divides the inspection area into a plurality of inspection areas in a unit after tilting the read image based on the detection information from the tilt detection unit, and sets the image of the inspection area as a comparison image.

4. The image inspection apparatus according to any one of claims 1 to 3,

the inspection control unit enlarges the divided region to divide the image when the image is defective at the time of division.

5. The image inspection apparatus according to any one of claims 1 to 4,

the inclination detection unit is present at least at 2 places between the time of image writing and the time of image reading for inspection, and the inspection control unit performs inclination correction of the image based on the detection information of the 2 inclination detection units.

6. The image inspection apparatus according to any one of claims 1 to 5,

the inspection area is a print area in an area divided by a certain unit.

7. The image inspection apparatus according to any one of claims 1 to 6,

the inspection control unit sets the read area to be wider than the width of the recording medium, detects the end of the recording medium, and performs image analysis to detect the inclination, or the inclination and deviation of the recording medium.

8. The image inspection apparatus according to any one of claims 1 to 7,

when the inspection area is larger than a predetermined size, the inspection area is divided and cut out, and the inspection is performed in units of the division.

9. The image inspection apparatus according to any one of claims 1 to 8,

the amplitude of fluctuation caused by wriggling of the recording medium is predicted, and the image is read in a range larger than a predetermined range.

10. The image inspection apparatus according to any one of claims 1 to 9,

the divided region of a certain unit includes a region overlapping with an adjacent divided region to ensure a region where no image loss due to tilt occurs.

11. The image inspection apparatus according to any one of claims 1 to 10,

the inspection control unit detects the deviation of the continuous transfer medium and corrects the image even during the skew detection.

12. The image inspection apparatus according to any one of claims 1 to 11,

the inspection control unit deletes the data of the read image that is read continuously in units of divided areas excluding the overlapping portion used in the next division after the inspection is completed.

13. The image inspection apparatus according to any one of claims 1 to 12,

the inspection control unit executes one or both of warning display and stop of the printing operation when the amount of inclination of the image exceeds the allowable range.

14. The image inspection apparatus according to any one of claims 1 to 13,

the change of the detected inclination amount or inclination amount and deviation amount is monitored, the inclination amount or inclination amount and deviation amount in the future is predicted, and when it is determined that an image defect occurs in the current divided region as a result of correction of the inclination of the image of the inspection region based on the predicted inclination amount or inclination amount and deviation amount, the divided region is enlarged in advance from the set region.

15. The image inspection apparatus according to any one of claims 1 to 14,

the inspection control unit monitors a change state of the inclination amount or the inclination amount and the deviation amount detected at the time of writing, predicts the inclination amount or the inclination amount and the deviation amount in the future, and performs writing correction based on the inclination amount or the inclination amount and the deviation amount at the time of writing in advance.

16. The image inspection apparatus according to claim 14 or 15,

the inspection control unit monitors the state of change in the inclination amount or the inclination amount and the deviation amount, predicts the inclination amount or the inclination amount and the deviation amount in the future, and displays a warning in advance when it is determined that the state exceeds a correctable range.

17. The image inspection apparatus according to any one of claims 1 to 16,

the image forming apparatus includes a reading unit that reads an image of a recording medium on which the image is formed.

18. The image inspection apparatus according to any one of claims 1 to 17,

the image forming apparatus includes an image forming unit that forms an image on a recording medium.

19. A computer-readable storage medium storing a program, characterized in that,

the program is executed by an inspection control unit that acquires a read image obtained by reading an image of a recording medium on which an image has been formed, divides an inspection area by a certain unit from the read image to prepare a comparison image, and determines normality/abnormality of the image based on the comparison image,

the program causes the inspection control unit to receive information on the inclination of the recording medium and to perform the image normality/abnormality determination by inclining the image of the inspection area based on the information.

20. The computer-readable storage medium storing a program according to claim 19,

the inspection control unit divides the image into a plurality of inspection regions, and then tilts the image of the inspection region based on the tilt information as a comparison image.

21. The computer-readable storage medium storing a program according to claim 19,

the inspection control unit divides an inspection area by a certain unit after tilting the read image based on the tilt information, and sets an image of the inspection area as a comparison image.

22. The computer-readable storage medium storing a program according to any one of claims 19 to 21,

the inspection control unit enlarges the divided region to divide the image when the image is defective at the time of division.

23. The computer-readable storage medium storing a program according to any one of claims 19 to 22,

the inclination information is detected at least 2 points between the time of image writing and the time of image reading for inspection, and the inspection control unit performs inclination correction of the image based on 2 pieces of the inclination information.

24. The computer-readable storage medium storing a program according to any one of claims 19 to 23,

the inspection area is a print area in an area divided by a certain unit.

25. The computer-readable storage medium storing a program according to any one of claims 19 to 24,

the inspection control unit sets the read area to be wider than the width of the recording medium, detects the end of the recording medium, and performs image analysis to detect the inclination, or the inclination and deviation of the recording medium.

26. The computer-readable storage medium storing a program according to any one of claims 19 to 25,

when the inspection area is larger than a predetermined size, the inspection area is divided and cut out, and the inspection is performed in units of the division.

27. The computer-readable storage medium storing a program according to any one of claims 19 to 26,

the amplitude of fluctuation caused by wriggling of the recording medium is predicted, and the image is read in a range larger than a predetermined range.

28. The computer-readable storage medium storing a program according to any one of claims 19 to 27,

the divided region of a certain unit includes a region overlapping with an adjacent divided region to ensure a region where no image loss due to tilt occurs.

29. The computer-readable storage medium storing a program according to any one of claims 19 to 28,

the inspection control unit detects the deviation of the continuous transfer medium and corrects the image even during the skew detection.

30. The computer-readable storage medium storing a program according to any one of claims 19 to 29,

the inspection control unit deletes the data of the read image that is read continuously in units of divided areas excluding the overlapping portion used in the next division after the inspection is completed.

31. The computer-readable storage medium storing a program according to any one of claims 19 to 30,

the inspection control unit executes one or both of warning display and stop of the printing operation when the amount of inclination of the image exceeds the allowable range.

32. The computer-readable storage medium storing a program according to any one of claims 19 to 31,

the change of the detected inclination amount or inclination amount and deviation amount is monitored, the inclination amount or inclination amount and deviation amount in the future is predicted, and when it is determined that an image defect occurs in the current divided region as a result of correction of the inclination of the image of the inspection region based on the predicted inclination amount or inclination amount and deviation amount, the divided region is enlarged in advance from the set region.

33. The computer-readable storage medium storing a program according to any one of claims 19 to 32,

the inspection control unit monitors a change state of the inclination amount or the inclination amount and the deviation amount detected at the time of writing, predicts the inclination amount or the inclination amount and the deviation amount in the future, and performs writing correction based on the inclination amount or the inclination amount and the deviation amount at the time of writing in advance.

34. The computer-readable storage medium storing a program according to claim 32 or 33,

the inspection control unit monitors the state of change in the inclination amount or the inclination amount and the deviation amount, predicts the inclination amount or the inclination amount and the deviation amount in the future, and displays a warning in advance when it is determined that the state exceeds a correctable range.

35. The computer-readable storage medium storing a program according to any one of claims 19 to 34,

the inspection control unit controls reading of an image of a recording medium on which the image is formed.

36. The computer-readable storage medium storing a program according to any one of claims 19 to 35,

the inspection control unit controls the formation of an image on a recording medium.

Technical Field

The present invention relates to an image inspection apparatus and a program for determining normality or abnormality of an image based on a read image obtained by reading a recording medium.

Background

In the field of image forming apparatuses such as copiers, printers, and multifunction machines, there is known a method of determining normality or abnormality of an image using image reading data obtained by reading an image of a sheet.

For example, by comparing a read image with an accurate image such as image data for printing and determining whether or not the image matches the accurate image, abnormality determination such as dirt, color shift, and positional deviation is performed, or information on a streak is detected by a failure diagnosis function to diagnose a failure portion of a machine. This determination is generally referred to as a waste paper determination. Determination of used paper is performed not only on cut paper but also on continuous paper such as roll paper.

For example, patent document 1 proposes a defect inspection apparatus for optically and continuously detecting a defective portion from image data obtained by imaging an elongated sheet-like object to be inspected on which a repetitive image pattern is formed by an image sensor camera. The apparatus has a function of automatically learning a mask pattern based on image data representing a repeating image pattern on a subject obtained by imaging, and performing mask processing while learning repeating pitches of patterns in the image data every time, thereby eliminating accumulation of pitch errors accompanying initial setting of the mask pattern and improving accuracy of defect inspection.

Further, patent document 2 proposes a product inspection apparatus including: a product inspection unit that inspects whether a defective position of a product of the sheet-like printed matter exists; a marking unit for marking an identification mark on the product detected as the defective position by the product inspection unit; and a mark presence/absence checking unit for checking whether or not the identification mark is marked at the position of the product having the defective position. In this apparatus, the inspection is performed on the printed product of 1 cycle, so that the defective attachment of the identification label by the marking unit can be reliably inspected, and the defective product can be prevented from entering the market due to the detachment of the identification label.

Patent document 1: japanese laid-open patent publication No. 1-311377

Patent document 2: japanese laid-open patent publication No. 9-109372

However, when the method is applied to a printer using long paper, roll paper, or the like, since inclination correction cannot be performed until all printing is completed if paper-based waste paper detection is performed, there are problems in that real-time performance of waste paper detection is impaired, and cost is increased to secure an enormous memory for storing and correcting a read image. Therefore, by dividing the inspection data into units and performing the inclination correction, it is possible to ensure real-time inspection of the used paper and to suppress an increase in cost for ensuring a large memory.

However, in printing using roll paper or the like, the roll paper or the like often meanders, and in the case of meandering, a part of the paper is in a state of being inclined. When the roll paper is tilted during conveyance, there is a problem that if the read images are directly compared, the image is determined to be an abnormal image tilted with respect to a normal image, and normal paper waste detection cannot be performed.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image inspection apparatus and a program that can correct an inspection area in a certain unit according to a tilt when a recording medium is tilted, thereby enabling normal detection.

That is, a first aspect of the image inspection apparatus of the present invention is an image inspection apparatus including:

an inspection control unit that acquires a read image obtained by reading an image of a recording medium on which an image has been formed, divides an inspection area by a certain unit from the read image to prepare a comparison image, and determines whether the image is normal or abnormal based on the comparison image; and

a tilt detecting unit for detecting a tilt state caused by the wriggling of the recording medium,

the inspection control unit receives detection information from the inclination detection unit, and performs image normality/abnormality determination by inclining the image of the inspection area based on the detection information.

In another aspect of the present invention, in the image inspection apparatus according to the aspect of the present invention, the inspection control unit divides the image into a plurality of units and then tilts the image of the inspection area based on the detection information from the tilt detection unit as the comparison image.

In another aspect of the invention, in the image inspection apparatus according to the aspect of the invention, the inspection control unit divides the inspection area into a plurality of inspection areas in a unit after tilting the read image based on the detection information from the tilt detection unit, and sets the image of the inspection area as the comparison image.

In another aspect of the present invention, in the image inspection apparatus according to the aspect of the present invention, the inspection control unit enlarges the divided region to divide the image when the image is defective at the time of division.

In another aspect of the invention, in the image inspection apparatus of the above aspect of the invention, the tilt detector is present at least 2 positions between the time of image writing and the time of image reading for inspection, and the inspection controller performs tilt correction of the image based on the detection information of the 2 tilt detectors.

In another aspect of the invention, in the image inspection apparatus according to the aspect of the invention, the inspection area is a print area among areas divided in a certain unit.

In another aspect of the invention, in the image inspection apparatus according to the aspect of the invention, the inspection control unit sets the reading area to be wider than the width of the recording medium, detects the end of the recording medium, and performs image analysis to detect the inclination or the inclination and deviation of the recording medium.

In another aspect of the invention, in the image inspection apparatus according to the aspect of the invention, when the inspection area is larger than a predetermined size, the inspection area is divided and cut out, and the inspection is performed in units of the divided inspection area.

In the image inspection apparatus according to the other aspect of the present invention, the swing width caused by the wriggling of the recording medium is predicted, and the image is read in a range larger than a predetermined range.

In the image inspection apparatus according to the other aspect of the invention, in the invention according to the above aspect, the divided region of a certain unit includes a region overlapping with an adjacent divided region so as to secure a region where no image defect due to inclination occurs.

In another aspect of the invention, in the image inspection apparatus according to the aspect of the invention, the inspection control unit detects a deviation of the continuous transfer medium and corrects the image, even at the time of the inclination detection.

In another aspect of the invention, in the image inspection apparatus according to the aspect of the invention, the inspection control unit deletes the data of the read image that is read continuously in units of the division areas excluding the overlapping portion used in the next division after the inspection is completed.

In another aspect of the present invention, in the image inspection apparatus according to the aspect of the present invention, the inspection control unit executes one or both of a warning display and a stop of the printing operation when the amount of inclination of the image exceeds an allowable range.

In another aspect of the present invention, in the image inspection apparatus according to the above aspect of the present invention, the change of the detected inclination amount or inclination amount and deviation amount is monitored, the inclination amount or inclination amount and deviation amount in the future is predicted, and when it is determined that an image defect occurs in the current divided area as a result of correction of the inclination of the image in the portion of the inspection area based on the predicted inclination amount or inclination amount and deviation amount, the divided area is enlarged in advance more than the set area.

In another aspect of the invention, in the image inspection apparatus according to the aspect of the invention, the inspection control unit monitors a change in the inclination amount or the inclination amount and the deviation amount detected at the time of writing, predicts a future inclination amount or the inclination amount and the deviation amount, and performs writing correction based on the inclination amount or the inclination amount and the deviation amount at the time of writing in advance.

In another aspect of the invention, in the image inspection apparatus according to the aspect of the invention, the inspection control unit monitors a change state of the inclination amount or the inclination amount and the deviation amount, predicts a future inclination amount or inclination amount and deviation amount, and displays a warning in advance when it is determined that the change state exceeds a correctable range.

In the image inspection apparatus according to the other aspect of the present invention, the image inspection apparatus further includes a reading unit configured to read an image of the recording medium on which the image is formed.

In the image inspection apparatus according to the other aspect of the present invention, the image forming unit is configured to form an image on a recording medium.

A first aspect of the computer-readable storage medium storing a program according to the present invention is a program executed by an inspection control unit that acquires a read image obtained by reading an image of a continuous recording medium on which an image has been formed, divides an inspection area by a certain unit from the read image to prepare a comparison image, determines normality/abnormality of the image based on the comparison image,

the inspection control unit receives the inclination information of the continuous recording medium and performs the image normality/abnormality determination by inclining the image of the inspection area portion based on the information.

According to the present invention, it is possible to appropriately perform normality and abnormality of an image by tilting the image of an inspection area in a certain unit according to the tilt of a recording medium during conveyance.

Drawings

Fig. 1 is a mechanical schematic diagram showing an image forming apparatus including an image inspection apparatus according to an embodiment of the present invention.

Fig. 2 is a diagram showing a control block as well.

Fig. 3 is a diagram illustrating a state in which an image of roll paper is read in divided areas and inspected.

Fig. 4 is a top view for explaining a state in which the roll paper is tilted and the image inspection cannot be normally performed, and a bottom view for explaining a state in which the image inspection of the image is normally performed by tilting the image of the divided area in consideration of the tilted image.

Fig. 5 is a top view for explaining a state in which the roll paper is tilted and the inspection of the image cannot be normally performed, and a bottom view for explaining a state in which the inspection of the image is normally performed by tilting the read image through the divided area.

Fig. 6 is a diagram illustrating a state in which the divided regions are enlarged when a defect occurs in the comparison image.

Fig. 7 is a diagram showing a state in which divided regions overlap each other when a large region is secured so that no image loss due to a tilt occurs in a divided region of a certain unit.

Fig. 8 is a diagram illustrating a state in which the inspection region is divided and the inspection is performed when the divided region is large and the inclination amounts are different between the front end and the rear end.

Fig. 9 is a diagram showing a screen on which a warning is displayed with a large bend of the sheet.

Fig. 10 is a diagram showing an operation display screen displayed when the image inspection cannot be normally performed in the future according to the inclination tendency.

Fig. 11 is a flowchart showing a procedure of detecting the tilt of the image, acquiring the divided images, correcting the tilt and deviation of the divided images based on the detection information, and checking the images.

Fig. 12 is a flowchart showing a procedure of detecting the tilt of an image, correcting the tilt and the deviation of the read image based on the detection information, acquiring a divided image, and checking the image.

Detailed Description

Hereinafter, an embodiment of an image forming apparatus including an image inspection apparatus according to the present invention will be described with reference to the drawings.

As shown in fig. 1, the image forming apparatus 1 includes a paper feed unit 200, a paper feed adjustment unit 300, an apparatus main body 10, a paper discharge adjustment unit 400, and a paper discharge unit 500 in this order from the upper stage in the paper conveyance direction. The units are electrically and mechanically connected to each other, and communication between the units and movement of the paper can be performed.

Roll paper or the like described later is conveyed from the paper feed unit 200 toward the paper discharge unit 500. The number and type of devices constituting the image forming apparatus 1 are not particularly limited, and other devices such as a post-processing device may be provided. Further, the image forming apparatus may be constituted by only the apparatus main body, or the image forming system may be constituted by the image forming apparatus constituted by the apparatus main body and other parts.

The image forming apparatus 1 includes a conveyance path 22 from the paper feeding unit 200 to the paper discharging unit 500, and a conveyance roller 23 and the like are provided on the conveyance path 22. The paper feed unit 200 stores roll paper RP, and the roll paper RP in the paper feed unit 200 is conveyed to each subsequent section through the conveyance path 22.

The roll paper RP corresponds to one of the recording media in the present invention. The recording medium of the present invention is not limited to roll paper, and may be a sheet in which a long sheet is folded and stored, such as continuous account paper. Further, as the recording medium of the present invention, a recording medium that can print a plurality of pages without reducing the size, such as a long cut paper longer than a set paper, may be used instead of a continuous recording medium. That is, the present invention can be applied to a long recording medium such as roll paper, continuous account paper, long cut paper, or the like.

The recording medium is not limited to paper, and may be cloth, plastic, or the like.

The paper feed adjusting unit 300 absorbs the difference in the conveyance speed between the paper feed unit 200 and the apparatus main body 10 and the deviation of the paper.

The apparatus main body 10 is an apparatus for forming an image on a sheet, and is provided with an image forming unit 110 for forming an image on a sheet in an electrophotographic manner in the middle of the conveyance path 22. The image forming unit 110 includes a photoreceptor 110A for each color, and a charger, an LD, a developing unit, a cleaning unit, and the like, which are not shown, are provided around the photoreceptor 110A. The photosensitive bodies 110A for the respective colors are in contact with the intermediate transfer belt 110B, and the intermediate transfer belt 110B can be in contact with the roll paper RP on the conveyance path 22 at the secondary transfer portion 110C.

Further, a skew sensor 24 that detects the skew of the paper being conveyed is provided in the conveyance path 22 on the upstream side of the image forming unit 110. The configuration of the inclination sensor 24 is not particularly limited, and for example, a configuration in which inclination information is obtained by optically detecting both end front end surfaces of the paper sheet can be used. The tilt sensor 24 corresponds to a tilt detection unit of the present invention.

The tilt sensor may be disposed before the print sheet reading unit 600 described later, or may be provided at 2 or more positions together with the tilt sensor 24. In the present invention, the position and number of the tilt sensors are not limited to a specific configuration.

Further, a fixing unit 110D is provided on the conveyance path 22 downstream of the secondary transfer unit 110C. In the case of forming an image on a sheet of paper, after the photoreceptor 110A is uniformly charged by the charger, a latent image is drawn on the photoreceptor 110A by the LD based on image data. Then, the latent image on the photoreceptor 110A is developed by the toner adhering to the developer, and a toner image is formed. The toner images on the photosensitive member 110A are transferred to the intermediate transfer belt 110B so that the toner images for the respective colors overlap, and the toner images on the intermediate transfer belt are transferred to a sheet of paper in the secondary transfer portion 110C. The toner image transferred to the paper is fixed to the paper by being heated and pressed by the fixing section 110D.

An Automatic Document Feeder (ADF)135 is provided above the housing of the apparatus main body 10. The set document is automatically conveyed by an Automatic Document Feeder (ADF)135, and an image of the document is read by a CCD (image reading unit) of the scanner unit. The image data obtained by reading is used for image formation or the like.

Further, an operation display unit 140 is provided on the upper portion of the housing of the device main body 10. The operation display unit 140 includes a touch panel LCD, an operation key group, and the like, and can display information and perform operation input. The operation display unit 140 may set the processing contents when the image has an abnormality, and the processing (stop of printing, etc.) according to the inclination of the roll paper.

The apparatus main body portion 10 further includes a control portion 100. The control unit 100 is configured by a CPU, a ROM, a RAM, a program operating in the CPU, and the like, and can control the entire image forming apparatus 1. The program operating in the CPU includes the program of the present invention. In the present embodiment, the control unit 100 corresponds to an inspection control unit of the present invention.

Next, a control block of the image forming apparatus 1 will be described with reference to fig. 2.

The image forming apparatus 1 includes a control unit 100. The control unit 100 includes a CPU101, a ROM102, and a RAM 103. The ROM102 stores programs and parameters for controlling the image forming apparatus 1, and the control unit 100 can read the programs stored in the ROM102 by the CPU101 and control the operations of the respective units of the image forming apparatus 1. The control unit 100 controls the entire image forming apparatus 1, and is configured to perform status recognition, and perform task management, image formation control, continuous paper conveyance control, paper reading control, image inspection based on a read image, and the like. Therefore, the control unit 100 can function as an inspection control unit of an image inspection apparatus, and in this case, the image forming apparatus includes the image inspection apparatus of the present invention.

The control unit 100 is connected to a storage unit 104, and the storage unit 104 includes an HDD (hard disk drive), a nonvolatile memory, and the like capable of storing information in a nonvolatile manner. The storage unit 104 can store data of a read image read by the print sheet reading unit 600, reference image data for image inspection, print image data of a job, print setting information of a job, and the like. The image data for printing the job can be obtained by reading a document by an image reading unit 135A included in an Automatic Document Feeder (ADF)135 or by receiving the document from the outside.

Further, the storage unit 104 stores therein initial setting information of the apparatus main body 10, machine setting information such as process control parameters, information on a division area of the read image, parameters, and the like. In addition, these programs and parameters may be stored in a portable and removable storage medium. The control unit 100 can determine normality or abnormality of an image based on a read image of a sheet by reading a program or a parameter stored in the nonvolatile memory and dividing an inspection area in a certain unit.

The control unit 100 is connected to the print sheet reading unit 600 in a controllable manner, and the control unit 100 acquires a read image and determines normality or abnormality of the image. The print sheet reading unit 600 is provided with an in-line sensor or the like for reading an image. The control section 100 takes the read image data read by the print sheet reading section 600 as comparison image data, and performs image inspection by comparison with reference image data prepared in advance. At this time, the inclination of the sheet is detected by the inclination sensor 24, and the comparative image after the inclination correction is used for the determination based on the detection information.

The control unit 100 is connected to a communication unit 105. The communication unit 105 can communicate with other devices via a network, can receive task data, image data, and the like from an external device on the network, and can transmit image data, image inspection results, and the like to the outside. For example, the print job and the inspection information can be transferred to another device connected to the network, and the image inspection result can be transferred at this time.

The control unit 100 is connected to an image processing unit 106. The image processing unit 106 performs image processing such as reading of image data and writing of an image. When writing an image, various image processing such as layout processing such as rotation, enlargement, reduction, page number addition, page merge, thinning processing, density correction processing, and halftone processing for analog reproduction of halftone can be performed.

The paper conveying unit 220 is connected to the control unit 100 in a controllable manner. The paper conveying unit 220 is configured by the conveying path 22, the conveying roller 23, a motor not shown that drives a roller that is rotationally driven, and the like, and conveys roll paper and the like.

The control unit 100 is also connected to an image forming unit 110 in a controllable manner. In the image forming section 110, an image is formed by an electrophotographic process, and an image is formed on a recording medium such as roll paper. The roll paper on which the image is formed and the like is fixed by the fixing unit 110D, and printing is completed.

Further, an operation display unit 140 is connected to the control unit 100 so as to be controllable. The operation display unit 140 includes a touch panel LCD, and can perform operation input and information display. That is, the operation display unit 140 can input operation control conditions such as settings and operation commands in the image forming apparatus 1. For example, the operation display unit 140 can set whether or not an image inspection is performed, set the division of an inspection area of a read image, and the like.

The operation display unit 140 can display desired information, for example, a read image and an inspection image. The operation display unit 140 serves as both the display unit 140A and the operation unit 140B.

In the present embodiment, the description has been given of the configuration in which the control unit 100 is provided in the casing of the apparatus main body 10, but the control unit 100 may be provided outside the casing of the apparatus main body 10.

Next, the basic operation of the image forming apparatus 1 will be described.

In the control unit 100, when printing is performed, the roll paper RP is fed by the paper feed unit 200. The roll paper RP is conveyed by the paper conveying unit 220D, and the inclination of the paper is detected by the inclination sensor 24, and the detection information is sent to the control unit 100.

Further, the control section 100 controls the image forming section 110. In the image forming unit 110, a toner image is written on each photoreceptor based on image data by an electrophotographic process, and after the toner image written on each photoreceptor is transferred to the intermediate transfer belt 110B, the toner image is secondarily transferred to the roll paper fed by the paper feed unit 200, and the image is fixed by the fixing unit 110D.

The image data may be acquired by an Automatic Document Feeder (ADF)135 or may be acquired from the outside through a communication unit 160.

The roll paper after image formation is subjected to image reading by the print sheet reading unit 600, and image inspection is performed in the control unit 100 based on the read image as described above. After that, the roll paper is conveyed to the paper discharge portion 500 via the paper discharge adjustment portion 400 along the conveyance path 22, and is wound into a roll in the paper discharge portion 500.

In the present embodiment, the configuration in which the control unit 100 functions as the inspection control unit of the present invention has been described, but the print sheet reading unit 600 may be provided with an inspection control unit to perform image inspection. In this case, the printed sheet reading portion 600 functions as an image inspection apparatus.

The inspection control unit may be provided outside the image forming apparatus via a communication unit or the like, and may be provided in a server or a terminal, for example, to determine whether an image is normal or abnormal. In this case, the server and the terminal function as an image inspection apparatus.

Next, reading of an image in the image forming apparatus 1 will be described.

Fig. 3 is a view showing a concept of successively read images read by the reading unit. In the continuously read image, image columns of each page shown on the right side of the figure are continuously arranged along the conveying direction of the sheet.

When reading an image, a divided region is set in accordance with a region of a page assumed from the arrangement of the images, and the image region is included in the divided region. In this method, the first image region is set as a correct image region, and the next and subsequent image regions are set as inspection regions. The correct image may be an image prepared in advance.

As shown in fig. 3, in a state where no inclination is generated in the sheet, the image is read for each predetermined divided region and is set as a comparison image, and the comparison image is compared with the correct image to determine whether the comparison image is correct or abnormal. In the case of an image abnormality, it is possible to warn as waste paper or stop printing.

On the other hand, if the paper is tilted due to winding of the roll paper, the image is tilted with respect to the divided region as shown in the upper part of fig. 4, and therefore the read image is also tilted, and the detection of the used paper cannot be normally performed in comparison with the correct image.

Therefore, in the present embodiment, the inclination of the roll paper is detected by the inclination sensor 24. As shown in the lower part of fig. 4, in the present embodiment, after the read image is acquired in the divided region determined in advance, the read image in the inspection region can be tilted based on the detection information of the tilt sensor and comparison processing can be performed.

In addition, as shown in the upper stage of fig. 5, it is conceivable to incline the area where images are continuously read in consideration of the inclination of the roll paper. However, even if the inspection area is divided into a certain unit and the image of the inspection area is used as a comparison image after the continuously read image is tilted, the acquired image is tilted as the divided area is maintained, and therefore, the detection of the used paper cannot be appropriately performed.

At this time, as shown in the lower part of fig. 5, the divided region is tilted to obtain a clipped image, and this is used as a comparison image for determination.

As described above, even when the roll paper is tilted, it is possible to acquire an image corrected based on the tilt and determine whether the image is normal or abnormal. However, even if the tilt is increased, if the clipped area is kept constant, as shown in fig. 6, a part of the clipped image may be clipped, and the detection of used paper may not be performed normally. In fig. 6, image defects occur in the read image at the left and right ends, and normal determination of waste paper cannot be performed in comparison with an accurate image.

In this case, the divided area can be enlarged in the sheet conveying direction from the first predetermined area to perform reading so as not to cause an image defect. Further, even if the divided area is enlarged to a predetermined size, if the defect does not disappear, it is possible to warn as an error or stop printing.

In addition, if it is necessary to secure a large area in order to prevent image loss due to inclination in a certain unit of divided area, there is a case where read images are superimposed on each divided area as shown in fig. 7. In the comparison image, the overlapped images are removed to determine whether the images are normal or abnormal. In addition, in the determination, since the overlapped image is removed, it is preferable that the divided region to be inspected next is performed after the inspection from which the overlapped portion is removed is completed.

In addition, when the length of the divided area (for example, the length of 1 page) is long as shown in the right drawing of fig. 8, the inclination of the sheet may be different between the leading end and the trailing end of the roll paper. In such a case, as shown in the left drawing of fig. 8, the divided regions may be divided in the sheet conveying direction, and the image may be inspected using the divided regions.

Further, when the inclination of the sheet exceeds a set value (for example, when the curve is large), the image cannot be normally inspected, and therefore, a warning can be given or printing can be stopped. Fig. 9 shows an example in which a warning is given on a warning screen 1400 of the operation display unit 140 and printing is stopped because the inclination exceeds the allowable range. Further, the warning or the like may be notified to a server, a terminal, or the like via a network or the like.

In addition, the inclination of the paper is monitored and the trend is grasped, and the value thereof can be predicted. If it is predicted that the future inclination will exceed the allowable range, the possibility that the inspection cannot be normally performed may be warned, and a stop instruction may be issued. Fig. 10 shows a warning instruction screen 1410 displayed on the operation display unit 140, and when a stop button 1411 is pressed, printing can be stopped. When the close button 1412 is pressed, the screen can be closed to continue printing.

When the inclination of the paper is detected, the reading area is set to be wider than the width of the recording medium, and the inclination of the recording medium can be detected by detecting the edge of the recording medium and performing image analysis. In this case, the deviation of the sheet can be detected together with the inclination of the sheet. In the case of performing correction based on the inclination, the correction may be performed in consideration of the deviation of the sheet. In this case, the deviation may be monitored and the trend may be predicted in the same manner as the inclination.

The procedure of detecting the inclination of the roll paper and inspecting the image will be described with reference to the flowchart of fig. 11. The following process is executed by the control of the control unit.

The sheet is detected by the skew sensor (step s1), and based on the detection information, it is determined whether or not correction of skew or misalignment is necessary (step s 2).

When the correction of the inclination and the deviation is not necessary (no at step s2), a divided image is acquired from the read image in a certain unit (step s 3). The certain unit is, for example, a page unit. However, the present invention is not limited to this, and an appropriate range can be determined in advance.

Next, a comparison process is performed in which the print area is cut out, a comparison image is obtained, and the comparison image is compared with a correct image (step s 4).

The results of the processing are compared, and whether the output is normal or not is determined (step s 5). If it is determined that the output is normal (yes at step s5), the unnecessary read image portion for which the comparison processing has ended is deleted from the storage unit (step s6), and it is determined whether or not all the checks have ended (step s 7). If all the checks are not finished (no at step s7), the process returns to step s1 to continue the detection of the tilt and deviation state and the subsequent steps. When all the checks are finished (yes at step s7), the process is finished. In the following description, the inclination and deviation of the roll paper are detected and the inclination and deviation are considered, but only the inclination of the roll paper may be considered as the present invention.

If the output is not normal in step s5 (no in step s5), processing at the time of abnormality (determination of used paper) is performed (step s 25). As the processing, stopping of output, warning display, and the like can be performed. The present invention is not particularly limited to the processing at the time of an image abnormality. After the processing in the abnormal state, the entire processing is terminated. In the case of an abnormality, the process may proceed to step s7 without stopping the output and continue the output.

In step s2, if the correction of the tilt and the deviation is required (yes in step s2), it is determined whether or not the check area is large and the tilt is different between the front end and the rear end (divided area of page 1, etc.) (step s 10). If there is no difference in the front and rear ends inclination (no at step s10), it is determined whether or not the inclination amount exceeds the allowable range (step s 11). When the front end and the rear end are inclined differently (yes at step s10), the divided regions are divided in the transport direction, and the divided regions are processed (step s12), and the process proceeds to step s 11.

In step s11, if the inclination amount does not exceed the allowable range (no in step s11), it is determined whether or not there is a possibility of an image defect based on the state of change in the inclination and the deviation amount (step s 13). If the inclination amount exceeds the allowable range in step s11 (yes in step s11), the process proceeds to step s25, and the process in the abnormal state is performed as described above.

If there is no possibility of image loss in accordance with the situation of change in the inclination and the amount of deviation (no at step s13), a divided image is acquired from the read image in a certain unit (step s 14). If there is a possibility of an image loss depending on the change of the inclination or the deviation (yes at step s13), the divided region is enlarged (step s15), and the process proceeds to step s 14.

After the divided image is acquired in step s14, it is determined whether or not there is no defect in the comparison image (step s 16). If there is no defect in the comparison image (yes at step s16), it is determined whether or not the correction range is exceeded in the future based on the tendency of inclination and deviation (step s 17).

When there is a defect in the comparison image (no at step s16), it is determined whether or not the comparison image is within the allowable range (step s 18). The allowable amount is preset. If the defect is within the allowable range (yes at step s18), the divided region is enlarged at step s15 described above, and a divided image is acquired (step s 16).

If it is not determined that the correction range is likely to be exceeded in the future based on the tendency of the inclination and the deviation (no at step s17), the inclination and the deviation correction is performed on the divided image (step s 19). If it is determined that the correction range is likely to be exceeded in the future based on the inclination and deviation tendency (yes at step s17), a warning display process is performed (step s20), and whether or not the process is stopped is determined (step s 21). Whether or not to stop may be input by an operator operation, or may be predetermined in advance by a machine setting so as not to stop. Without stopping the operation (no at step s21), the process proceeds to step s19, and the divided image is corrected for tilt and deviation as described above. When the stop is performed (yes at step s21), a stop process is performed (step s 22).

After the tilt and offset correction is performed in step s19 as described above, it is determined whether or not the tilt and offset correction is appropriate to be taken into consideration at the time of writing (step s 23). In this determination, the determination may be performed based only on the detection result of the above-described inclination sensor 24, or the inclination sensor may be provided in front of the printed sheet reading unit 600 and the determination may be performed based on the detection information. For example, if the correction load at the time of reading can be reduced by reducing the inclination and deviation of the image by the correction at the time of writing, the correction at the time of writing may be performed.

If it cannot be said that the correction at the time of writing is appropriate (no at step s23), the process proceeds to step s4, and the print area is cut out to execute the comparison process as described above. In the case where it is appropriate to consider correction at the time of writing (yes at step s23), it is instructed to perform tilt and deviation correction at the time of writing (step s24), and move to step s 4.

In the above example, the case where the inclination and deviation correction is performed on the divided image obtained from the read image has been described, but the inclination and deviation correction may be performed on the read image, and then the divided image may be acquired. This example will be described below based on the flowchart of fig. 12. The following process is executed by the control of the control unit.

The sheet is detected by the skew sensor (step s1), and based on the detection information, it is determined whether or not correction of skew or misalignment is necessary (step s 2).

When the correction of the inclination and the deviation is not necessary (no at step s2), a divided image is acquired from the read image in a certain unit (step s 3). The certain unit is, for example, a page unit. However, the present invention is not limited to this, and an appropriate range can be determined in advance.

Next, a comparison process is performed in which the print area is cut out, a comparison image is obtained, and the comparison image is compared with a correct image (step s 4).

It is determined whether or not the result output of the comparison process is normal (step s 5). If the output is normal (yes at step s5), the unnecessary read image portion for which the comparison processing has ended is deleted from the storage section (step s6), and it is determined whether or not all the checks have ended (step s 7). If all the checks are not finished (no at step s7), the process returns to step s1 to continue the detection of the tilt and deviation state and the subsequent steps. When all the checks are finished (yes at step s7), the process is finished.

If the output is not normal in step s5 (no in step s5), processing at the time of abnormality (determination of used paper) is performed (step s 25). As the processing, stopping of output, warning display, and the like can be performed. The present invention is not particularly limited to the processing at the time of an image abnormality. After that, the process is ended. In the case of an abnormality, the process may proceed to step s7 without stopping the output and continue the output.

In step s2, if the correction of the tilt and the deviation is required (yes in step s2), it is determined whether or not the check area is large and the tilt is different between the front end and the rear end (divided area of page 1, etc.) (step s 10). If there is no difference in the front and rear end inclinations (no at step s10), it is determined whether or not the inclination amount exceeds the allowable range (step s 11). When the front end and the rear end are inclined differently (yes at step s10), the divided regions are divided in the transport direction, and the divided regions are processed (step s12), and the process proceeds to step s 11.

In step s11, if the tilt amount does not exceed the allowable range (no in step s11), tilt and deviation correction is performed on the read image (step s 30). If the inclination amount exceeds the allowable range in step s11 (yes in step s11), the process proceeds to step s25, and the process in the abnormal state is performed as described above.

After the process of step s30, it is determined whether or not there is a possibility of an image defect based on the state of change in the inclination and the deviation amount (step s 13).

If there is no possibility of image loss in accordance with the situation of change in the inclination and the amount of deviation (no at step s13), a divided image is acquired from the read image in a certain unit (step s 14). If there is a possibility of image loss depending on the situation of change in the inclination and the deviation amount (yes at step s13), the divided region is enlarged (step s15), and the process proceeds to step s14 described above.

After the divided image is acquired in step s14, it is determined whether or not there is no defect in the comparison image (step s 16). If there is no defect in the comparison image (yes at step s16), it is determined whether or not there is a possibility of exceeding the correction range in the future based on the tendency of inclination and deviation (step s 17).

When there is a defect in the comparison image (no at step s16), it is determined whether or not the comparison image is within the allowable range (step s 18). The allowable amount is preset. If the defect is within the allowable range (yes at step s18), the divided region is enlarged at step s15 described above, and a divided image is acquired (step s 16).

In the case where it is not determined that there is a possibility of exceeding the correction range in the future from the tendency of the inclination and the deviation (no at step s17), it is determined whether it is appropriate to consider the inclination and the deviation correction at the time of writing (step s 23). If the correction at the time of writing is not suitable for consideration (no at step s23), the process proceeds to step s4, and the print area is cut out to perform the comparison processing as described above. In the case where it is appropriate to consider correction at the time of writing (yes at step s23), it is instructed to perform tilt and deviation correction at the time of writing (step s24), and move to step s 4.

If it is determined that the correction range is likely to be exceeded in the future based on the inclination and deviation tendency (yes at step s17), a warning display process is performed (step s20), and whether or not the process is stopped is determined (step s 21). Whether or not to stop may be input by an operator operation, or may be predetermined in advance by a machine setting so as not to stop. Without stopping the operation (no at step s21), the process proceeds to step s21, where the divided image is corrected for tilt and deviation as described above. When the stop is performed (yes at step s21), a stop process is performed (step s 22).

The present invention has been described above based on the above embodiments, but the present invention is not limited to the above description, and appropriate modifications can be made to the above embodiments without departing from the scope of the present invention.

Description of the reference numerals

1 … image forming apparatus; 24 … tilt sensor; 100 … control section; 101 … CPU; 102 … ROM; 103 … RAM; 104 … storage section; 105 … communication section; 106 … image processing unit; 110 … image forming part; 110D … fixing section; 135a … image reading section; 140 … operation display part; 200 … paper supply part; 300 … paper feeding adjustment part; 400 … paper discharge regulating part; 500 … paper discharge section; 600 … print a sheet reading portion.