Image forming device

Abstract

To provide an image forming apparatus that can accurately settle the size of a document regardless of the thickness of the document.SOLUTION: An image forming apparatus 100 comprises a reading unit 1, a document thickness detection unit 61, a first document end detection unit 62, a second document end detection unit 63, and a document size settlement unit 65. The reading unit 1 creates an original image including an image of a document G. The document thickness detection unit 61 detects the thickness of the document G. When the thickness of the document G is equal to or more than a threshold, the first document end detection unit 62 detects a peripheral shape of the document G based on the shape of a shadow generated on a peripheral part of the document G. When the thickness of the document G is less than the threshold, the second document end detection unit 63 presents the original image to a user and detects the peripheral shape of the document G based on designation made by the user. The document size settlement unit 65 settles the size of the document G according to a result of detection performed by the first document end detection unit 62 or a result of detection performed by the second document end detection unit 63.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] The image reading device described in Patent Document 1 determines whether the document type is thick paper or thin paper based on the image data of the read document. The CPU (Central Processing Unit) of the image reading device detects the thickness of the document based on the magnitude of the gradation deviation of the shadow, utilizing the fact that the gradation value of the shadow that appears on the edge of the document varies when the document type is thin paper. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-121146 Summary of the Invention [Problem to be solved by the invention]

[0004] In the image reading device described in Patent Document 1, when the document type is thin paper, the gradation value of the shadow that appears on the edge of the document fluctuates, so it is not possible to determine the size of the document with high accuracy.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can determine the size of a document with high accuracy regardless of the thickness of the document. [Means for solving the problem]

[0006] A first image forming apparatus of the present invention includes a reading unit, a document thickness detection unit, a first document edge detection unit, a second document edge detection unit, and a document size determination unit. The reading unit generates an original image including an image of a document. The document thickness detection unit detects the thickness of the document. When the thickness detected by the document thickness detection unit is equal to or greater than a threshold, the first document edge detection unit detects the peripheral shape of the document based on the shape of a shadow generated at the peripheral edge of the document. When the thickness detected by the document thickness detection unit is less than the threshold, the second document edge detection unit presents the original image to a user and detects the peripheral shape of the document based on a specification by the user. The document size determination unit determines the size of the document according to the detection result of the first document edge detection unit or the detection result of the second document edge detection unit.

[0007] A second image forming apparatus of the present invention includes a reading unit, a document thickness detection unit, a first document edge detection unit, a third document edge detection unit, and a document size determination unit. The reading unit generates an original image including an image of a document. The document thickness detection unit detects the thickness of the document. When the thickness detected by the document thickness detection unit is equal to or greater than a threshold, the first document edge detection unit detects the peripheral shape of the document based on the shape of a shadow generated at the peripheral edge of the document. When the thickness detected by the document thickness detection unit is less than the threshold, the third document edge detection unit detects the peripheral shape of the document based on the shape of a partial image included in the document. The document size determination unit determines the size of the document according to the detection result of the first document edge detection unit or the detection result of the third document edge detection unit. [Effects of the Invention]

[0008] According to the present invention, an image forming apparatus is provided that can determine the size of a document with high accuracy regardless of the thickness of the document. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating an example of a structure of an image forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing an example of a circuit configuration of an image forming apparatus. [Figure 3] 10 is a flowchart illustrating an example of the operation of a control unit. [Figure 4] 10A and 10B are diagrams illustrating an example of an operation procedure of the first document end detection unit. [Figure 5] 10A and 10B are diagrams illustrating an example of an operation procedure of the second document end detection unit. [Figure 6] 10A and 10B are diagrams illustrating an example of an operation procedure of the third document end detection unit. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the accompanying drawings, in which the same or corresponding parts are designated by the same reference numerals and will not be described repeatedly.

[0011] An image forming apparatus 100 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing an example of the configuration of the image forming apparatus 100. The image forming apparatus 100 is, for example, a copier, a printer, a facsimile, or a multifunction device that combines the functions of these.

[0012] As shown in FIG. 1, the image forming apparatus 100 includes a reading unit 1, a feeding unit 2, a conveying unit 3, an image forming unit 4, a fixing unit 5, and a discharging unit 6.

[0013] The reading unit 1 reads an image of an original G. The reading unit 1 generates image data from the read image. For example, the reading unit 1 has an automatic document feeder (ADF), a platen cover, a contact glass, and an optical reading mechanism. When the platen cover is closed, the original G is set in the ADF and automatically transported, and the image of the original G is read. The user can also open the platen cover and place an original G, such as an ID card, on the contact glass to have the image of the original G read.

[0014] The feeding unit 2 stores a plurality of sheets S and feeds the sheets S to the conveying unit 3. The sheets S are made of, for example, paper or synthetic resin. The conveying unit 3 includes a plurality of pairs of conveying rollers and conveys the sheets S to the image forming unit 4.

[0015] The image forming unit 4 forms a toner image on the sheet S by electrophotography. The image forming unit 4 includes a photosensitive drum, a charging device, an exposure device, a developing device, a replenishing device, a transfer device, a cleaning device, and a discharging device. The fixing unit 5 heats and pressurizes the toner image to fix the toner image to the sheet S. The conveying unit 3 conveys the sheet S with the fixed toner image to the discharge unit 6. The discharge unit 6 discharges the sheet S outside the image forming apparatus 100.

[0016] 1 and 2, the circuit configuration of the image forming apparatus 100 will be described. FIG. 2 is a block diagram showing an example of the circuit configuration of the image forming apparatus 100.

[0017] As shown in FIG. 2, the image forming apparatus 100 further includes an operation unit 10, a control unit 60, and a storage unit .

[0018] The operation unit 10 serves as both an input device for various user operations and a display device for displaying messages to the user. The operation unit 10 includes, for example, a touch panel 11 and a plurality of push buttons.

[0019] The storage unit 70 includes a storage device and stores data and computer programs, and includes a main storage device such as a semiconductor memory and an auxiliary storage device such as a hard disk drive (HDD).

[0020] The storage unit 70 has, for example, an input image memory 71 and an output image memory 72. The reading unit 1 generates an original image including an image of the document G. The input image memory 71 stores data of the original image. The output image memory 72 stores data indicating the image of the document G cut out from the original image.

[0021] The control unit 60 includes a processor such as a CPU, and controls each component of the image forming apparatus 100 by executing a computer program stored in the storage unit 70. The control unit 60 also functions as a document thickness detection unit 61, a first document end detection unit 62, a second document end detection unit 63, a third document end detection unit 64, a document size determination unit 65, and an image cropping unit 66 by executing the computer program stored in the storage unit 70.

[0022] The document thickness detection unit 61 detects the thickness of the document G. For example, the document thickness detection unit 61 detects the thickness of the document G according to the magnitude of the gradation deviation of the shadow, utilizing the fact that the gradation value of the shadow that appears on the periphery of the document G varies when the thickness of the document G is small.

[0023] The first document edge detector 62 detects the peripheral shape of the document G based on the shape of a shadow that appears on the peripheral edge of the document G when the thickness of the document G is equal to or greater than a threshold value.

[0024] In response to the user's first selection, if the thickness of the document G is less than a threshold value, the second document edge detection unit 63 presents the user with an original image including an image of the document G and detects the peripheral shape of the document G based on the user's specifications.

[0025] The third document edge detection unit 64 automatically detects the peripheral shape of the document G based on the shape of a partial image included in the document G in response to the user's second selection if the thickness of the document G is less than the threshold value.

[0026] The document size determination unit 65 determines the size of the document G according to the detection result of the first document end detection unit 62, the detection result of the second document end detection unit 63, or the detection result of the third document end detection unit 64.

[0027] The image cutout unit 66 cuts out the image of the document G from the original image including the image of the document G in accordance with the size of the document G determined by the document size determination unit 65.

[0028] Next, the operation of the control unit 60 will be described with reference to Figs. 1 to 3. Fig. 3 is a flowchart showing an example of the operation of the control unit 60. A user can request the image forming apparatus 100 to perform cropping to the document size via the operation unit 10. The user can also provide the image forming apparatus 100 with a selection via the operation unit 10 as to whether or not the user wishes to automatically detect the peripheral shape of the document G.

[0029] Step S101: As shown in Fig. 3, the control unit 60 causes the reading unit 1 to start scanning the document G. When the process of step S101 is completed, the process of the control unit 60 proceeds to step S103.

[0030] Step S103: The control unit 60 determines whether or not the document size cropping is valid. If the control unit 60 determines that the document size cropping is valid (Yes in step S103), the process of the control unit 60 proceeds to step S105. If the control unit 60 determines that the document size cropping is not valid (No in step S103), the process of the control unit 60 ends.

[0031] Step S105: The control unit 60 detects the thickness of the document G according to the magnitude of the gradation deviation of the shadow occurring at the peripheral edge of the document G.

[0032] Step S107: The control unit 60 determines whether the thickness of the original G is equal to or greater than the threshold value. If the control unit 60 determines that the thickness of the original G is equal to or greater than the threshold value (Yes in step S107), the process of the control unit 60 proceeds to step S109. If the control unit 60 determines that the thickness of the original G is less than the threshold value (No in step S107), the process of the control unit 60 proceeds to step S111.

[0033] Step S109: The control unit 60 executes the procedure for detecting the first document end, which will be described later with reference to Fig. 4. When the process of step S109 is completed, the process of the control unit 60 proceeds to step S117.

[0034] Step S111: The control unit 60 determines whether automatic detection of the peripheral shape of the document G is enabled. If the control unit 60 determines that automatic detection of the peripheral shape is enabled (Yes in step S111), the process of the control unit 60 proceeds to step S115. If the control unit 60 determines that automatic detection of the peripheral shape is not enabled (No in step S111), the process of the control unit 60 proceeds to step S113.

[0035] Step S113: The control unit 60 executes the procedure for detecting the second document end, which will be described later with reference to Fig. 5. When the process of step S113 is completed, the process of the control unit 60 proceeds to step S117.

[0036] Step S115: The control unit 60 executes a third document end detection procedure, which will be described later with reference to Fig. 6. When the process of step S115 is completed, the process of the control unit 60 proceeds to step S117.

[0037] Step S117: The control unit 60 determines the size of the original G according to the result of the first original end detection, the second original end detection, or the third original end detection.

[0038] Step S119: The control unit 60 cuts out the image of the document G from the original image including the image of the document G in accordance with the size of the document G determined in step S117. When the process of step S119 is completed, the process of the control unit 60 ends.

[0039] Next, the operation procedure of the first document end detection unit 62 will be described with reference to Fig. 4. Fig. 4 is a diagram showing an example of the operation procedure of the first document end detection unit 62. The document G is, for example, an ID card placed on the contact glass.

[0040] 4, the first document end detection unit 62 acquires an original image including an image of the document G from the input image memory 71. Because the thickness of the document G is equal to or greater than the threshold, a clear shadow appears on the periphery of the document G in the original image.

[0041] Step S203: Subsequently, the first document end detection unit 62 executes an edge extraction operation on the original image.

[0042] Step S205: Next, the first document end detecting unit 62 deletes unnecessary data that does not contribute to the peripheral shape of the document G from the extracted edges.

[0043] Step S207: Subsequently, the first document end detection unit 62 executes a straight line extraction operation on the original image from which unnecessary data has been deleted.

[0044] Step S209: Subsequently, the first document end detection unit 62 executes an operation to extract the outermost lines from the extracted straight lines.

[0045] Step S211: Finally, the first document end detection unit 62 detects a rectangle that indicates the peripheral shape of the document G based on the position of the extracted outermost line.

[0046] Next, the operation procedure of the second document end detection unit 63 will be described with reference to Fig. 5. Fig. 5 is a diagram showing an example of the operation procedure of the second document end detection unit 63. Because the thickness of the document G is less than the threshold, a shadow is unlikely to appear on the peripheral edge of the document G in the original image, and the first document end detection unit 62 may erroneously detect the peripheral shape of the document G.

[0047] Step S301: As shown in FIG. 5, the second document end detection unit 63 presents an original image including an image of the document G to the user via the touch panel 11 and prompts the user to specify three points on the original image that indicate the document ends.

[0048] Step S303: The user designates three points on the original image that indicate the document edges. Subsequently, the second document edge detection unit 63 acquires the position information of the three points on the original image designated by the user.

[0049] Step S305: Finally, the second document end detection unit 63 detects a rectangle that indicates the peripheral shape of the document G based on the acquired position information of the three points.

[0050] Next, the operation procedure of the third document end detection unit 64 will be described with reference to Fig. 6. Fig. 6 is a diagram showing an example of the operation procedure of the third document end detection unit 64. Because the thickness of the document G is less than the threshold, a shadow is unlikely to appear on the peripheral edge of the document G in the original image, and the first document end detection unit 62 may erroneously detect the peripheral shape of the document G.

[0051] Step S401: As shown in FIG. 6, the third document end detection unit 64 acquires an original image including an image of the document G from the input image memory 71.

[0052] Step S403: Subsequently, the third document end detection unit 64 executes an operation to binarize the original image.

[0053] Step S405: Next, the third document edge detection unit 64 detects isolated areas from the binarized original image. An isolated area indicates an area where black is connected to a white background, and includes partial images of objects such as characters and figures contained in the document G. Furthermore, a rectangle circumscribing each isolated area is drawn.

[0054] Step S407: Next, the third document end detection unit 64 combines rectangles circumscribing each isolated region, and the circumscribing rectangles include all objects.

[0055] Step S409: Subsequently, the third document end detection unit 64 detects the inclination and the positions of the four sides of the document G based on the combined circumscribing rectangle.

[0056] Step S411: Finally, the third document end detection unit 64 detects a rectangle that indicates the peripheral shape of the document G based on the detected inclination of the document G and the positions of the four sides.

[0057] According to the embodiment, an image forming apparatus 100 is provided that can determine the size of the original G with high accuracy regardless of the thickness of the original G.

[0058] The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above embodiments and can be embodied in various forms without departing from the spirit and scope of the present invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in the above embodiments. For example, some components may be omitted from all components shown in the embodiments. The drawings mainly show each component in a schematic manner for ease of understanding, and the number of each component shown may differ from the actual number due to the convenience of drawing. Furthermore, the components shown in the above embodiments are merely examples and are not particularly limited, and various modifications are possible without substantially departing from the effects of the present invention.

[0059] In the embodiment, the image forming apparatus 100 is of an electrophotographic type, but is not limited to this. For example, the image forming apparatus 100 may be of an inkjet type.

[0060] In addition, in the embodiment, the thickness of the document G is detected according to the magnitude of the gradation deviation of the shadow that appears at the peripheral edge of the document G, but this is not limited to this. If the ADF has a double feed detection sensor that detects the degree of attenuation of ultrasonic waves when they pass through the document G, the double feed detection sensor can be used to detect the thickness of the document G. [Industrial Applicability]

[0061] The present invention can be used in the field of image forming devices. [Explanation of symbols]

[0062] 1 Reading unit 4 Image forming unit 60 Control Unit 61 Document thickness detection unit 62 First document edge detection unit 63 Second document edge detection unit 64 Third document edge detection unit 65 Document size determination section 66 Image cropping section 100 Image forming device G Manuscript

Claims

1. a reading unit that generates an original image including an image of a document; a document thickness detection unit that detects the thickness of the document; a first document edge detection unit that detects a peripheral shape of the document based on a shape of a shadow generated at a peripheral edge of the document when the thickness detected by the document thickness detection unit is equal to or greater than a threshold value; a second document edge detection unit that, when the thickness detected by the document thickness detection unit is less than the threshold value, presents the original image to a user and detects a peripheral shape of the document based on a specification by the user; an original size determination unit that determines the size of the original in accordance with a detection result from the first original end detection unit or a detection result from the second original end detection unit; An image forming apparatus comprising:

2. a reading unit that generates an original image including an image of a document; a document thickness detection unit that detects the thickness of the document; a first document edge detection unit that detects a peripheral shape of the document based on a shape of a shadow generated at a peripheral edge of the document when the thickness detected by the document thickness detection unit is equal to or greater than a threshold value; a third document edge detection unit that detects a peripheral shape of the document based on a shape of a partial image included in the document when the thickness detected by the document thickness detection unit is less than the threshold value; an original size determination unit that determines the size of the original in accordance with a detection result of the first original end detection unit or a detection result of the third original end detection unit; An image forming apparatus comprising:

3. 3. The image forming apparatus according to claim 1, further comprising an image cutting section that cuts out an image of the document from the original image in accordance with the size of the document determined by the document size determining section.

Images