JP2019068258A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect the size of a document in both an open state and a closed state of a document holding member while suppressing an increase in cost. SOLUTION: A document size detecting unit 102 is read by a document reading unit 5 within a predetermined distance from the back side of a document placing surface in a state where a light source of the document reading unit 5 is lit. By specifying the document placement area in the sub-scanning direction based on the obtained image data, the size of the document in the sub-scanning direction is detected, and the pixel value of the image data portion within the range is predetermined. If it is determined that the value is equal to or greater than the threshold value, the size of the document in the sub-scanning direction is detected again by detecting the shadow of the rear edge of the document in the sub-scanning direction from the captured image data. [Selection diagram] Fig. 3

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, when the document pressing member is opened, a platen glass (a document (document) is obtained in the state where the exposure lamp (light source) is not lit and in the state where it is lit. 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 becomes black. There is. 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 flexibly cope with the sizes of various originals (in particular, ID cards and forms) in the sub-scanning direction, many dedicated sensors must be installed, which also increases the cost.

  The size of the ID card is set to various sizes according to the international standard (ISO 7810). For example, the size of the credit card is set to 53.98 × 85.60 mm, the size of the passport is set to the size of B7 size But not one. In addition, there are innumerable document sizes.

  With regard to ID cards, there may be cases where it is desirable to combine both front and back sides into one recording sheet and to further center and copy the front and back sides, but to achieve these, the size of the ID card Accurate detection is important.

  The present invention has been made in view of the above circumstances, and can accurately detect the size of a document while the document pressing member is open or closed while suppressing an increase in cost. The purpose is

  If the light source disposed below the document placement surface is turned on with the document placed on the document placement surface when the document pressing member is open, the document placement on which the document is placed In the storage area, the light emitted from the light source is reflected by the document, and in the area where the document does not exist, the light emitted from the light source is not reflected. Therefore, the size of the document can be detected by detecting the presence or absence of the reflected light by the reading sensor and specifying the document placement area. Specifically, the image data of the portion where the reflected light is incident on the reading sensor is a white image (in the case of an original white sheet), and the image data of the other portion is a black image.

  However, as described above, when the document pressing member is open, even in the area where the document does not exist, the light emitted from the light source is reflected by the document pressing member and scattered light, and the lighting fixture attached to the ceiling There is a possibility that external light from the light source or the like enters the reading sensor as disturbance light, and the image data of the portion other than the document placement area becomes a white image.

  The reading sensor is roughly classified into a CCD method and a CIS (Contact Image Sensor) method, but the CIS method is more susceptible to disturbance light than the CCD method. 1 and 2 are explanatory diagrams for explaining the influence of disturbance light. In each of FIG. 1 and FIG. 2, (A) is a schematic view showing the positional relationship between the document pressing member and the document loading surface, and (B) is a document loading condition with the document pressing member open. FIG. 8 is a diagram showing an example of image data obtained when the entire original placement surface is scanned without being placed. Further, FIG. 1 shows a case where a CCD is adopted as a reading sensor, and FIG. 2 shows a case where a CIS is adopted as a reading sensor.

  The original mat 61, which functions as an original pressing member, is openable and closable on one end side of the reading device (this is the rear side of the apparatus) so as to be able to contact and release the upper surface of the platen glass 161 for placing the original. It is supported. In FIG. 1B, the image data DA is image data obtained by reading with a light source provided to the reading sensor when the CCD is employed as the reading sensor, and the vertical direction in the figure is the sub-scanning direction. The horizontal direction in the drawing is the main scanning direction. The image indicated by the image data DA is a black image as a whole, and the white image WH extends in a band shape in the sub-scanning direction at a position away from the back side of the platen glass 161. The white image portion is a portion affected by disturbance light, but the portion is relatively narrow.

  The image data DB shown in FIG. 2B is image data obtained by reading when the light source provided to the reading sensor is turned on when the CIS is adopted as the reading sensor. The image indicated by the image data DB is a black image (gray image) BL from the back side of the platen glass 161 and a portion less than the distance LA, and the other portion is a white image. Although the white image portion affected by the disturbance light is relatively wide, the range less than the distance LA from the back side of the platen glass 161 is not a white image. Therefore, within this range, the document placement area can be specified even when the document pressing member is open.

  Further, as shown in FIG. 1B, even if the reading sensor is a CCD, the image represented by the image data DA in the range from the back side of the platen glass 161 to the distance LA is also a black image. If it is inside, the document placement area can be specified even when the document pressing member is open. Therefore, the range can be said to be a range not affected by disturbance light in that the document placement area is specified.

  The image reading apparatus according to one aspect of the present invention is a document pressing member supported openably and closably with respect to the document placement surface on one end side of the apparatus main body, and the surface facing the document placement surface is white. And a light source for emitting light along the main scanning direction toward the document placed on the document placement surface, and scanning the document while moving the light source in the sub scanning direction, A document reading unit that receives light reflected from the document and reads an image of the document; and a state in which the light source is on when the document pressing member is in an open state away from the document placement surface Detected as the size of the document in the sub-scanning direction, using the image data obtained by reading by the document reading unit within the range of a predetermined distance in the main scanning direction from the one end side of the document mounting surface Document size detection And the document size detection unit is configured to generate a black image from the document reading start position in the image data indicating the document image at each position in the sub scanning direction from the document reading start position by the document reading unit in the sub scanning direction. An area in the sub scanning direction up to a line where an image equal to or less than a predetermined value representing an image appears is an image area obtained by reading the document, and the sub scanning direction distance of the image area is the document area in the sub scanning direction. When the first detection for detecting as the size is performed, and the document size detection unit further determines that the pixel value of the image data portion in the range in the first detection is equal to or more than a predetermined threshold value, In the image data obtained by reading by the document reading unit with the light source turned on, the image data is formed by the document trailing edge in the sub scanning direction. To detect a shadow image indicating a shadow, and secondly detecting a distance from a line at a start position of the image data in the sub scanning direction to a line indicating the shadow image as the size of the document in the sub scanning direction .

  According to the present invention, in a state in which the light source is on when the document pressing member is open, the document pressing member is previously supported from the one end side of the apparatus main body supported openably and closably with respect to the document placement surface. The size of the document in the sub-scanning direction is detected based on the image data obtained by reading by the document reading unit within the range of the defined distance.

  Since the place close to the one end side of the document placement surface is not affected by the disturbance light even when the document pressing member is open, the document placement area in the sub-scanning direction can be specified accurately. Therefore, even when the document pressing member is open, the size of the document in the sub scanning direction can be accurately detected. Therefore, since it is not necessary to newly install a dedicated sensor for detecting the size of the document in the sub scanning direction, it is possible to suppress the increase in cost.

  On the other hand, when the document pressing member is closed, it is not affected by the disturbance light, but the reflected light from the document pressing member erroneously detects that the document is present even in the portion where the document does not exist, and the document placement area is accurately determined. There is a possibility that it can not be identified.

  However, according to the present invention, when the pixel value of the image data portion within the range in the first detection is equal to or greater than a predetermined threshold (that is, the lightness of the image is the reflected light by the white portion of the document pressing member). The size of the document in the sub-scanning direction is detected by detecting the shadow of the rear end of the document in the sub-scanning direction if it is assumed that reading from the Be fixed. 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 subscanning direction to the shadow image Is detected as the size of the document in the sub-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.

It is an explanatory view for explaining the influence of disturbance light. It is an explanatory view for explaining the influence of disturbance light. 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. 8 is an explanatory diagram for describing a method of detecting the size of a document in the sub scanning direction. FIG. 8 is an explanatory diagram for describing a method of detecting the size of a document in the sub 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. 3 is a functional block diagram schematically showing the main internal configuration of the image forming apparatus provided with the image reading apparatus according to the first embodiment of the present invention, and FIG. 4 relates to 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, an operation unit 47, and a mat open / close detection sensor 51.

  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. The document reading unit 5 is provided with a mat open / close detection sensor 51 for detecting the open / close state of the document mat 61. The document mat 61 has a white surface facing the platen glass 161 as a document placement surface. 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. Either a CCD (Charge Coupled Device) or a CIS (Contact Image Sensor) may be adopted as the document reading unit 5, but in the present embodiment, a case where a CCD is adopted 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 the control unit 100, the operation receiving unit 101, and the document size detection unit 102 by an operation according to a control program stored in the HDD 92 (Hard disk drive). 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, the operation unit 47, the HDD 92, and the mat open / close detection sensor 51, and drives these units. Control etc.

  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. 5 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 sub scanning direction when a user instruction to start reading the document M1 placed on the platen glass 161 is given will be described.

  (1-1) Detection of the size of the document M1 in the sub-scanning direction when it is assumed that the document mat 61 is in the open state will be described.

  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. While the document reading unit 5 is moved in the subscanning direction from the document reading start position in the subscanning direction to the end of the platen glass 161 in the subscanning direction opposite to the document reading start position. , And perform an original reading operation.

  Subsequently, as shown in FIG. 6, the document size detection unit 102 is within a range of a predetermined distance L1 (for example, about 3 mm) as shown in FIG. Image data obtained by reading by the document reading unit 5 is captured in a hatched area in FIG. The document size detection unit 102 detects the size of the document in the sub-scanning direction by specifying the document placement area (the region up to the rear end of the document) in the sub-scanning direction based on the captured image data. The above range is a range which is not affected by disturbance light when the document reading unit 5 performs reading by turning on the light source with the document mat 61 open. The distance L1 indicating the range is determined in advance by experiment, and is determined, for example, below the distance LA shown in FIG.

  In FIG. 7, the light source is turned on in a state where the document M1 is placed on the platen glass 161, and reading is performed by the document reading unit 5 within a predetermined distance L1 from the back side of the platen glass 161. It is the figure which showed an example of the obtained image data D1.

  The image indicated by the image data D1 is a white image (in the case where the document M1 is a white sheet) when the portion P1 is emitted from the light source and the reflected light reflected by the document M1 is incident on the reading sensor. It becomes a black image. That is, since the portion from the document reading start position on the left side of the platen glass 161 to the distance S1 becomes white, the document size detection unit 102 detects the distance S1 as the size of the document M1 in the subscanning direction. For example, in the image data D1 indicating the document image at each position in the sub scanning direction from the document reading start position, the document size detection unit 102 determines a predetermined value (for example, 256) indicating a black image from the document reading start position. In the case of gradation, an area up to the sub-scanning direction position where an image of 20 or less appears appears as an image area obtained by reading the document M1, and the sub-scanning direction distance of the area is detected as the size in the sub-scanning direction of the document M1. (First detection).

  (1-2) Detection of the size of the document M1 in the sub scanning direction when it is assumed that the document mat 61 is in a closed state will be described.

  The document size detection unit 102 determines, based on the image data obtained by reading by the document reading unit 5, a threshold at which the pixel value of the image data portion within the range of the predetermined distance L1 in the first detection is predetermined. It is determined whether or not (predetermined value indicating a white image; for example, 220 in the case of 256 gradations) or more.

  When the pixel value within the range is large (for example, when the pixel value is large due to the reflected light from the white part of the document mat 61 and the document mat 61 is assumed to be closed), the document M1 is The pixel value of the non-existent part and the pixel value of the part where the original M1 exists become close to each other, making it difficult to accurately distinguish the part where the original M1 does not exist and the part where the original M1 exists. May not be accurately identified.

  Therefore, if the document size detection unit 102 determines that the pixel value of the image data portion within the range is equal to or greater than a predetermined threshold value, the document trailing edge in the subscanning direction based on the captured image data. The size of the document M1 in the sub-scanning direction is redetected by detecting the shadow of. For example, if the document M1 is an ID card, depending on its thickness, the light from the light source of the document reading unit 5 emits a shadow on the rear end of the document, and the shadow is read by the document reading unit 5. The unit 102 detects a shadow image portion indicating the shadow from the captured image data. For example, the document size detection unit 102 detects a shadow image portion indicating the shadow by a known technique. The document size detection unit 102 detects the distance from the line of the start position of the captured image data in the sub scanning direction to the line indicating the shadow image as the size of the document M1 in the sub scanning direction (second detection).

  Further, when the document size detection unit 102 can not detect the shadow of the rear end of the document in the sub scanning direction, the document size detection section 102 determines the size of the document in the sub scanning direction to a predetermined maximum size (for example, the document reading unit The maximum scanable range in the main scanning direction 5 or the total length in the main scanning direction of the original mat 61 is detected.

  For example, if the document M1 is a form and the thickness is thin and a shadow can not be formed on the rear end of the document, the document size detection unit 102 detects the document size in the sub-scanning direction as the maximum size. Thus, it is possible to avoid a situation in which the width in the sub-scanning direction of the document image obtained by reading by the document reading unit 5 becomes smaller than that of the document.

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

  (2-1) When a user instruction to start reading of the document M1 placed on the platen glass 161 is issued with the document mat 61 open.

  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

  FIG. 8A shows an example of image data D2 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. 8B shows an example of image data D3 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 D2 as comparison image data, a portion P3 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 D3 is not only the portion P3 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 P4 is also a white image.

  Therefore, the document size detection unit 102 compares the image data D2 and the image data D3 and identifies an area (part P4) in which the data is different between the two image data as a document placement area. Document size detection unit 102 detects distance S2 (length of portion P4) from the back side of platen glass 161 (not shown) as the size of document M1 in the main scanning direction.

  (2-2) When the original mat 61 is closed.

  The control unit 100 controls the operation of the document reading unit 5 when it determines that it is immediately before the document mat 61 is completely closed, based on the detection signal obtained from the mat open / close detection sensor 51. The light source is turned on, and the document M1 placed on the platen glass 161 is read from the document reading start position, for example, a line extending in the main scanning direction.

  Subsequently, control unit 100 takes in the image data obtained by reading by document reading unit 5, and document size detection unit 102 detects the size of document M1 in the main scanning direction based on the taken image data. .

  In the place where the document M1 exists, light emitted from the light source is reflected by the document M1, and in the place where the document M1 does not exist, light emitted from the light source is not reflected by the document M1. Therefore, by detecting the presence or absence of the reflected light by the reading sensor, it is possible to specify the document placement area in the main scanning direction and detect the size of the document M1 in the main scanning direction.

  The light source is turned on immediately before the document mat 61 is completely closed, and the size of the document M1 in the main scanning direction is detected when the light source is turned on after the document mat 61 is completely closed. This is because the light is reflected by the document mat 61 even in the portion where the document is not placed, and erroneously detected as the reflected light from the document M1.

  According to the first embodiment, based on the image data obtained by reading by the document reading unit 5 within the range of the predetermined distance L1 from the back side of the platen glass 161 in the state where the light source is on. The size of the document M1 in the sub scanning direction is detected by specifying the document placement area in the sub scanning direction.

  A place close to the back side of the platen glass 161 is not affected by disturbance light even when the document mat 61 is open, so the document placement area in the sub-scanning direction can be accurately identified. Therefore, even when the document mat 61 is open, the size of the document M1 in the sub-scanning direction can be accurately detected.

  On the other hand, when the document mat 61 is closed, although it is not affected by disturbance light, the reflected light from the document mat 61 causes the portion where the document M1 does not exist to be erroneously detected as the document M1 and It can not be identified accurately.

  However, according to the first embodiment, when it is determined that the pixel value of the image data portion within the range of the predetermined distance L1 from the back side of the platen glass 161 is equal to or more than the predetermined threshold. By detecting the shadow of the rear end of the document in the sub-scanning direction, the size of the document M1 in the sub-scanning direction is redetected.

  As a result, the size of the document M1 can be properly detected regardless of whether the document mat 61 is open or closed. In addition, since it is not necessary to newly install a dedicated sensor for detecting the size of the document M1 in the sub scanning direction, it is possible to suppress the increase in cost.

  By continuously performing the document size detection of (1) and (2) described above, it is possible to detect the size in the sub-scanning direction and the size in the main scanning direction of the document M1. In the case of the size detection in the main scanning direction according to (2), (2-1) or (2-2) is selectively performed according to the open / close state of the document mat 61 under the control of the control unit 100.

  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. 9, 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 9 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 51 mat open / close detection sensor 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 (5)

A document pressing member which is supported openably and closably with respect to the document placement surface at one end side of the apparatus main body, and whose surface facing the document placement surface is white;
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;
In a state where the light source is on when the document pressing member is in the open state apart from the document placement surface, a distance of a predetermined distance in the main scanning direction from the one end side of the document placement surface A document size detection unit configured to detect a size of a document in the sub scanning direction using image data obtained by reading by the document reading unit within a range;
The document size detection unit is configured to display in advance a black image from the line at the document reading start position in the image data indicating the document image at each position in the sub scanning direction from the document reading start position by the document reading unit in the subscanning direction. An area in the sub-scanning direction up to the line where an image smaller than a predetermined value appears is taken as an image area obtained by reading the document, and the sub-scanning direction distance of the image area is detected as the size of the document in the sub-scanning direction Perform the first detection,
Furthermore, when the document size detection unit determines that the pixel value of the image data portion within the range in the first detection is equal to or more than a predetermined threshold value, the light source is turned on. In the image data obtained by reading by the document reading unit, a shadow image indicating a shadow formed by the rear end of the document in the sub scanning direction is detected, and the shadow image is detected from the line of the start position of the image data in the sub scanning direction An image reading apparatus which performs a second detection of detecting a distance to a line indicating the size of the document in the sub scanning direction;   The image reading apparatus according to claim 1, wherein the predetermined distance range is a predetermined range not affected by disturbance light.   When the document size detection unit can not detect the shadow of the document trailing edge when detecting the document size in the sub scanning direction by detecting the shadow of the document trailing edge, The image reading apparatus according to claim 1, wherein the size of the document in the scanning direction is set to a predetermined maximum size.   The document size detection unit further opens the image data obtained by reading by the document reading unit and the document pressing member in a state where the light source is not turned on when the document pressing member is open. In the state where the light source is turned on, the image data obtained by reading by the document reading unit is compared, and an area which is a different image data portion in both the image data is specified as a document placement area. The image reading apparatus according to any one of claims 1 to 3, wherein the size of the document in the main scanning direction is detected. 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 4, further comprising: a restriction unit which prohibits the erasing process up to the predetermined position.