JP2019068257A - Image reading device - Google Patents

Abstract

To accurately detect the size of a document in both states where a document holding member is open and the document holding member is closed, even when a sensor for detecting the opening/closing state of the document holding member is not provided.SOLUTION: A document size detection unit 102 performs first detection of specifying a document placement area in a main scanning direction on the basis of the difference between respective pieces of image data obtained through reading performed by a document reading unit 5 when its light source is turned on and off, thereby detecting the size of a document in the main scanning direction, when determining that the size of the document in the main scanning direction in the detection is the maximum size, detects a shadow image showing the shadow formed by the rear end of the document in the main scanning direction in the image data obtained through reading performed by the document reading unit 5 when the light source is turned on, and detects the distance from the starting position of the image data to the shadow image in the main scanning direction as the size of the document in the main scanning direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image reading apparatus, and more particularly to a technique for detecting the size of an original.

  Some image reading apparatuses have a function of detecting the size of a document placed on the document placement surface. As a means for detecting the size of the document in the main scanning direction, the light source is turned on immediately before the document pressing member (for example, document mat) is completely closed, and the size of the document is There is something to detect. On the other hand, as a means for detecting the size of the document in the sub scanning direction, a dedicated sensor (for example, a reflection type sensor) is provided in the area where the document of various sizes (B5 size, A4 size, B4 size, etc.) is placed. The document size is detected based on a combination of detection results from each sensor.

  However, with regard to the size of the document in the main scanning direction, the light source is turned on and detected before the document pressing member is completely closed. Therefore, the external light from the lighting fixture or the like attached to the ceiling is the reading light as disturbance light And may not be able to detect correctly.

  As an invention for solving such a problem, according to Patent Document 1 below, when the document pressing member is open, the contact glass (the document is turned on in a state where the exposure lamp (light source) is not lit and in a lit state. The document placed on the mounting surface is read by a CCD (Charge Coupled Device), and the portion affected by the disturbance light is specified based on the change in the image data obtained by these readings. It is described that the size in the width direction (main scanning direction) of the image sensor is accurately detected.

JP 2001-147494 A

  In the image reading apparatus, when the document placed on the document placement surface is read by a reading sensor such as a CCD while the document pressing member is open, the outer margin of the document may be read black. is there. In particular, reading of a document such as an ID card (for example, a credit card) or a slip (for example, a slip) is relatively often performed with the document pressing member open.

  In order to solve the situation where the outer margin portion of the document is read black, it is possible to execute the existing outside document original erasing function (function to whiten the area outside the document) as in the technology shown in the above-mentioned Patent Document 1. It is possible to adopt a new system, but the function is expensive and the cost increases.

  As another method, there is a method of detecting the size of the document placed on the document placement surface, setting the document reading size from the detected document size, and reading the document with the set reading size. Although it is conceivable, in order to detect the size of the document in the main scanning direction, a detection sensor for detecting the open / close state of the document pressing member is required as described in Patent Document 1 mentioned above. However, the above-mentioned detection sensor is not equipped in an inexpensive copying machine or the like having a simple configuration.

  The present invention has been made in view of the above circumstances, and it is possible to open and close the document pressing member without providing a sensor for detecting the open and closed state of the document pressing member. The purpose is to make it possible to accurately detect the size of a document.

  In the image reading apparatus according to one aspect of the present invention, a document pressing member supported openably and closably on a document placement surface, and a document placed on the document placement surface in the main scanning direction An original reading unit which has a light source for emitting light along and scans the original while moving the light source in the sub-scanning direction, receives reflected light from the original, and reads an image of the original; The size of the document in the main scanning direction is detected by specifying the document placement area in the main scanning direction based on the difference between the image data obtained by reading by the document reading unit when the light source is turned on and off. When the document size detection unit determines that the size of the document in the main scanning direction according to the first detection is a predetermined maximum size In the image data obtained by reading by the document reading unit while the light source is on, a shadow image indicating a shadow formed by the rear end of the document in the main scanning direction is detected, and the image in the main scanning direction is detected. A second detection is performed to detect the distance from the start position of the image data to the shadow image as the size of the document in the main scanning direction.

  According to the present invention, in a state in which the light source is turned on, the document placement area in the main scanning direction is specified based on the image data obtained by reading by the document reading unit. Size is detected.

  When the document pressing member is open, for example, the image indicated by the image data obtained by reading by the document reading unit is a white image (when the document is blank) while the portion where the document is present is Since the non-existent part is a black image, it is possible to specify the document placement area based on the difference between the two image data.

  On the other hand, when the document pressing member is closed, the reflected light of the document pressing member causes, for example, the above-mentioned image data in the maximum scanable range in the main scanning direction of the document reading unit or the entire length in the main scanning direction of the document pressing member. Since the image shown is a white image (when the document is white and the document pressing member is white), it is difficult to specify the document placement area based on the difference between the two image data.

  However, according to the present invention, when it is determined that the size of the document in the detected main scanning direction is the predetermined maximum size (that is, it is assumed that the document pressing member is closed). By detecting the shadow of the rear end of the document in the main scanning direction, the size of the document in the main scanning direction is redetected. For example, if the document is an ID card, a shadow is formed at the rear end of the document depending on the thickness, so a shadow image showing the shadow is detected, and from the start position of the read image data in the main scanning direction to the shadow image Is detected as the size of the document in the main scanning direction.

  Thus, the size of the document can be accurately detected in either the open or closed state of the document pressing member. Therefore, even if the sensor for detecting the open / close state of the document pressing member is not provided, the size of the document can be accurately detected.

FIG. 1 is a functional block diagram schematically showing a main internal configuration of an image forming apparatus including an image reading apparatus according to a first embodiment of the present invention. FIG. 1 is a perspective view showing an appearance of an image forming apparatus provided with an image reading apparatus according to a first embodiment. It is a figure which showed an example of the state in which the document was mounted on the platen glass, and was seen from the upper direction. FIG. 7 is an explanatory diagram for describing a method of detecting the size of a document in the main scanning direction. FIG. 6 is a functional block diagram schematically showing a main internal configuration of an image forming apparatus including an image reading apparatus according to a second embodiment.

  Hereinafter, an image reading apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram schematically showing a main internal configuration of an image forming apparatus provided with an image reading apparatus according to a first embodiment of the present invention, and FIG. 2 is a diagram showing the first embodiment. FIG. 1 is a perspective view showing an appearance of an image forming apparatus provided with an image reading apparatus.

  The image forming apparatus 1 is, for example, a multifunction peripheral having a plurality of functions such as a copy function, a printer function, a scanner function, and a facsimile function. The image forming apparatus 1 includes a control unit 10, a document feeding unit 6, a document reading unit 5, an image forming unit 12, a fixing unit 13, a sheet feeding unit 14, and an operation unit 47.

  The case where the document reading operation is performed in the image forming apparatus 1 will be described. The document reading unit 5 optically reads an image of a document conveyed by the document feeding unit 6 or a document placed on the platen glass 161, and generates image data. Image data generated by the document reading unit 5 is stored in an image memory or the like (not shown). The platen glass 161 is an example of the document placement surface in the claims.

  The document feeding unit 6 is configured to be able to open and close on the upper surface of the document reading unit 5 by a hinge or the like. The document feeding unit 6 includes a document mat 61 and reads a document placed on a platen glass 161 In this case, it functions as a document pressing member cover. The document mat 61 is an example of the document pressing member in the claims.

  The document reading unit 5 has a light source for emitting light toward the document placed on the platen glass 161 along the main scanning direction, and moves the light source line by line in the sub-scanning direction. Scanning is performed, and light reflected from the original is received to read an image of the original. Although either a CCD (Charge Coupled Device) or a CIS (Contact Image Sensor) may be adopted as the document reading unit 5. In the present embodiment, the case of employing a CCD will be described.

  The case where the image forming operation is performed in the image forming apparatus 1 will be described. Based on image data generated by a document reading operation, image data received from a computer as an external device connected to a network, etc., the image forming unit 12 records as a recording medium fed from the paper feeding unit 14. Form a toner image on paper.

  The fixing unit 13 fixes a toner image on a recording sheet by thermocompression bonding, and the recording sheet subjected to the fixing process is discharged to the discharge tray 151. The sheet feeding unit 14 includes a sheet feeding cassette.

  The operation unit 47 receives, from the operator, an instruction such as an image forming operation execution instruction for various operations and processes that can be executed by the image forming apparatus 1. The operation unit 47 includes a display unit 473 that displays operation guidance and the like to the operator. The display unit 473 is a touch panel, and the operator can operate the image forming apparatus 1 by touching a button or a key displayed on the screen.

  The control unit 10 is configured to include a processor, a random access memory (RAM), a read only memory (ROM), and a dedicated hardware circuit. The processor is, for example, a central processing unit (CPU), an application specific integrated circuit (ASIC), a micro processing unit (MPU) or the like. The control unit 10 includes a control unit 100, an operation receiving unit 101, and a document size detection unit 102.

  The control unit 10 functions as a control unit 100, an operation receiving unit 101, and a document size detection unit 102 by an operation according to a control program stored in a hard disk drive (HDD) 92. However, the control unit 100 and the like may be configured by hardware circuits, regardless of the operation according to the control program by the control unit 10. Hereinafter, the same applies to each embodiment unless otherwise noted.

  The control unit 100 is in charge of overall operation control of the image forming apparatus 1. The control unit 100 is connected to the document feeding unit 6, the document reading unit 5, the image forming unit 12, the fixing unit 13, the sheet feeding unit 14, and the operation unit 47, and performs drive control of these units.

  The operation receiving unit 101 receives an operation input from a user via the operation unit 47.

  Document size detection unit 102 detects the size of the document placed on platen glass 161.

  FIG. 3 shows an example of the document placed on the platen glass 161, as viewed from the top, and the document M1 (for example, an ID card) is placed according to the back corner C1 of the platen glass 161. Indicates the status of being One end portion side of the apparatus main body of the image forming apparatus 1 in which the document mat 61 is supported so as to be openable and closable with respect to the document mounting surface is a back side. Hereinafter, the means for detecting the size of the document will be described by taking as an example the case of detecting the size of the document M1 placed on the platen glass 161 in accordance with the back corner C1.

  (1) Detection of the size of the document M1 in the main scanning direction when there is a user instruction to start reading the document M1 placed on the platen glass 161 will be described.

  (1-1) The size detection of the document M1 in the main scanning direction under the assumption that the document mat 61 is in the open state is as follows.

  The control unit 100 controls the operation of the document reading unit 5 when the operation receiving unit 101 receives a user instruction to start reading the document M1 placed on the platen glass 161, whereby the light source of the document reading unit 5 is provided. The document M1 placed on the platen glass 161 is read from the document reading start position (for example, a position near the back corner C1 in the sub scanning direction), with a line, for example, one line extending in the main scanning direction. Then, the image data obtained by reading by the document reading unit 5 is stored as comparison image data.

  Subsequently, the control unit 100 controls the operation of the document reading unit 5 to turn on the light source of the document reading unit 5 and read one line of the document M1 placed on the platen glass 161 in the main scanning direction. Then, the image data obtained by reading by the document reading unit 5 is taken. The document size detection unit 102 detects the size of the document M1 in the main scanning direction by comparing the acquired image data with the comparison image data.

  For example, the document size detection unit 102 compares the captured image data with the image data as the comparison image data, and identifies the area where the data is different as the document placement area, thereby the document M1 in the main scanning direction. Detect the size of

  4A shows an example of image data D1 as comparison image data obtained by reading by the document reading unit 5 without turning on the light source in a state where the document M1 is placed on the platen glass 161. 4B shows an example of image data D2 obtained by reading by the document reading unit 5 with the light source turned on in a state where the document M1 is placed on the platen glass 161. As shown in FIG.

  In the image shown by image data D1 as comparison image data, a portion P1 where external light from a lighting fixture or the like attached to the ceiling is incident on the reading sensor as disturbance light is a white image, and the other portion is a black image It has become. On the other hand, the image data D2 is not only the portion P1 where the disturbance light is incident on the reading sensor but also the portion where the reflected light emitted from the light source and reflected on the document M1 (not shown) is incident on the reading sensor P2 is also a white image.

  Therefore, the document size detection unit 102 compares the image data D1 with the image data D2, and identifies an area (part P2) in which the data is different between the two image data as a document placement area. Document size detection unit 102 detects distance S1 (length of portion P2) from the back side of platen glass 161 (the start position of image data in the main scanning direction) as the size of document M1 in the main scanning direction.

  (1-2) The detection of the size of the document M1 in the main scanning direction under the assumption that the document mat 61 is in the closed state is as follows.

  The control unit 100 controls the operation of the document reading unit 5 to read by the document reading unit 5 when the light source provided to the document reading unit 5 is turned on and off as in the case of (1-1). The respective image data obtained in the above are stored as comparison image data. The original size detection unit 102 compares the read-in image data with the comparison image data, and for example, specifies an area where the data is different as an original placement area, whereby the distance S1 in the main scanning direction is set as an original. Detected as the size of M1 (first detection).

  Subsequently, the document size detection unit 102 determines whether the distance S1, which is the size of the document M1 in the detected main scanning direction, is a predetermined maximum size. The maximum size is set to the smaller one of the scannable maximum range in the main scanning direction of the document reading unit 5 or the total length in the main scanning direction of the document mat 61.

  Here, assuming that the document mat 61 is open, the image indicated by the image data obtained by reading by the document reading unit 5 is a white image (in the case of a document white sheet) in the portion where the document M1 exists. On the other hand, since the portion where the document M1 does not exist becomes a black image, the document placement area can be specified based on the image data.

  On the other hand, when the document mat 61 is closed, the reflected light of the document mat 61 indicates the image data in the maximum scannable range in the main scanning direction of the document reading unit 5 or the entire length in the main scanning direction of the document mat 61. Since the image is a white image (when the document is white and the document mat 61 is white), the total length in the main scanning direction is erroneously detected as the document size in the main scanning direction.

  Therefore, when the document size detection unit 102 determines that the distance S1 is the maximum size, the document rear end (platen in the main scanning direction) is obtained from the image data at the time of light source lighting obtained by reading by A shadow image showing a shadow formed by the document end opposite to the back side of the glass 161 is detected, and from the start position of the image data (back side of the platen glass 161) to the shadow image in the main scanning direction The distance is set to the size of the document M1 in the main scanning direction (second detection). For example, the document size detection unit 102 detects a shadow image portion indicating the shadow by a known technique. For example, if the document M1 is an ID card, the thickness of the document M1 causes a shadow on the back end of the document. In this case, in the image data, the portion where the document M1 exists becomes a white image (in the case of an original white sheet), and the shadow portion becomes a black image. The original size detection unit 102 sets the distance from the back side of the platen glass 161 (the start position of the image data in the main scanning direction) in the main scanning direction to the image showing the shadow to the original in the main scanning direction. The size of M1.

  When the document size detection unit 102 determines that the distance S1 is not the maximum size, the document size detection unit 102 adopts the size of the document M1 in the main scanning direction obtained by the first detection as the size of the document M1 in the main scanning direction. .

  (2) Detection of the size of the document M1 in the sub scanning direction will be described.

  As means for detecting the size of the document in the sub-scanning direction, not only the area for placing a document of various sizes (B5 size, A4 size, B4 size, etc.) but also various types of documents (for example, ID card or the like) There is also a method in which a dedicated sensor is installed also in the area where the form is placed, and the document size detection unit 102 detects the size of the document based on a combination of detection results from the respective sensors.

  Further, as another means, the document size detection unit 102 uses the document size in the subscanning direction of the document M1 from the information indicating the main scanning direction size and the subscanning direction size for a predetermined standard document size. There is size detection of determining the document size in the sub scanning direction corresponding to the detected document size in the main scanning direction.

  For example, when the original size detection unit 102 determines that the size of the original in the main scanning direction detected above is 53.98 mm and matches the short side length of the ID card which is a standard original size, the original M1 is an ID. It is determined that the card is a card, and the size of the document in the sub-scanning direction is determined to 85.60 mm. In this case, the document size detection unit 102 holds 53.98 mm and 85.60 mm (international standard (ISO 7810)) as the size in the main scanning direction and the size in the sub scanning direction for an ID card which is a standard document size. It shall be.

  According to the first embodiment, the following effects can be obtained.

  When the document mat 61 is open, the image indicated by the image data obtained by reading by the document reading unit 5 is a white image (when the document is a white sheet) whereas the portion where the document M1 exists is the document M1. Since the portion where there is no image is a black image, the document placement area can be specified based on the image data.

  On the other hand, when the original mat 61 is closed, the reflected light from the original mat 61 turns the portion where the original M1 does not exist also into a white image (when the original is white and the original mat 61 is white). It is erroneously detected, and the document placement area can not be accurately identified.

  However, according to the first embodiment, when the document size detection unit 102 determines that the size of the document M1 in the detected main scanning direction is the maximum size predetermined as described above (for example, the document With the mat 61 closed, the size of the document M1 in the main scanning direction is redetected by detecting the shadow of the rear end of the document in the main scanning direction). .

  As a result, the size of the document M1 in the main scanning direction can be accurately detected regardless of whether the document mat 61 is open or closed. Therefore, even if the sensor for detecting the open / close state of the original mat 61 is not provided, the size of the original M1 in the main scanning direction can be accurately detected.

  According to the document size detection process described in the above embodiment, even if the document reading unit 5 adopts either the CCD or CIS method, the above-described accurate document size detection is possible.

  By the way, some existing copiers and the like are equipped with a system capable of executing a frame erasing processing function for erasing the periphery of the document M1, but in the case of an ID card, various information is described up to the four sides If the process of erasing the periphery of the document M1 is performed by the frame erasing process, the frame erasing process erases the surrounding image to a position slightly inside the outline of the read document image. Since the setting is often made, important information may be deleted.

  Therefore, as a second embodiment, as shown in FIG. 5, the control unit 10 may be provided with a frame removal processing unit 103 and a limitation unit 104.

  The frame eraser 103 performs the existing frame erase process described above. The frame erasing processing unit 103 corrects the image data obtained by reading by the document reading unit 5 so that the document image portion up to a predetermined position (for example, 5 mm) inward of the contour of the document image Setting to erase the surrounding image of the original image.

  As in the first embodiment, the control unit 10 operates the control unit 100, the operation receiving unit 101, the document size detection unit 102, the frame removal processing unit 103, and the restriction by the operation according to the control program stored in the HDD 92. It functions as the unit 104. However, the control unit 100 and the like may be configured by hardware circuits, regardless of the operation according to the control program by the control unit 10.

  The restriction unit 104 is configured such that the size of the document M1 placed on the platen glass 161 is a predetermined size, for example, the size of an ID card, based on the document size detected by the document size detection unit 102. Is determined to be an ID card, or when the operation receiving unit 101 receives a designation by the user that the document M1 to be read is, for example, an ID card, the process from the contour of the document image to the above-described predetermined position The distance is reduced by a predetermined value (for example, when the distance to a predetermined position is 5 mm, the predetermined value is set to 2 mm), or the predetermined value is determined from the outline of the document image Prohibit delete processing up to the position.

  Thereby, when it is determined that the document M1 is an ID card, or when the user instructs "ID copy", for example, the range of deletion is narrowed from 5 mm to 3 mm, or the deletion is prohibited. As a result, it is possible to prevent the deletion of important information present near the outline of the original image.

  Further, the present invention is not limited to the configuration of the above embodiment, and various modifications are possible. Further, in the above embodiment, although a multifunction peripheral is described as one embodiment of the image reading apparatus according to the present invention, this is merely an example, and for example, it has a copy function, a facsimile function, a scanner function, etc. The other image reading apparatus may be used. Further, in the above embodiment, the configurations and processes shown by the above embodiment using FIGS. 1 to 5 are only one embodiment of the present invention, and the present invention is not limited to the configurations and processes.

Reference Signs List 1 image forming apparatus 5 document reading unit 61 document mat 100 control unit 101 operation receiving unit 102 document size detection unit 103 frame erasing processing unit 104 restriction unit 161 platen glass

Claims (4)

A document pressing member supported so as to be openable and closable with respect to a document placement surface;
The document has a light source for emitting light along the main scanning direction toward the document placed on the document placement surface, and the document is scanned while moving the light source in the sub scanning direction, and the document A document reading unit that receives the reflected light from the document and reads the image of the document;
The size of the document in the main scanning direction is determined by specifying the document placement area in the main scanning direction based on the difference between the image data obtained by reading by the document reading unit when the light source is turned on and off. A document size detection unit that performs a first detection to be detected;
When the document size detection unit determines that the size of the document in the main scanning direction according to the first detection is a predetermined maximum size, the document reading unit reads the document while the light source is on. In the image data obtained in the above, a shadow image indicating a shadow formed by the rear end of the document in the main scanning direction is detected, and the distance from the start position of the image data in the main scanning direction to the shadow image is An image reading apparatus that performs a second detection that detects the size of the document in   The document size detection unit, as the first detection, the image data obtained by reading by the document reading unit and the document pressing unit in a state where the light source is not turned on when the document pressing member is open. While the light source is on when the member is open, the image data obtained by reading by the document reading unit is compared, and an area which becomes a different image data portion in the two data is a document placement area. 2. The image reading apparatus according to claim 1, wherein the size of the document in the main scanning direction is detected by specifying.   3. The image according to claim 1, wherein the maximum size is a smaller one of a scannable maximum range in the main scanning direction of the document reading unit or a total length in the main scanning direction of the document pressing member. Reader. An operation reception unit that receives user input from the operation unit;
A frame that erases an ambient image including a document image portion that has entered to a predetermined position inside the contour of the document image indicated by the image data by correcting the image data obtained by reading by the document reading unit The eraser,
When it is determined that the document placed on the document placement surface is an ID card based on the document size detected by the document size detection unit, or the document to be read by the operation reception unit is an ID card When the user's designation by the user is accepted by the operation accepting unit, the distance from the contour of the document image to the predetermined position is reduced by a predetermined value, or from the contour of the document image The image reading apparatus according to any one of claims 1 to 3, further comprising: a restriction unit which prohibits the erasing process up to the predetermined position.