Image reading device and image forming system

Abstract

To provide an image reading device that can read an image from a document in the optimal condition according to the type of the document, and an image forming system comprising an image forming apparatus and such an image reading device.SOLUTION: In an image forming system, an image reading device 1005 comprises: a document platen glass 103 on which a document is placed; a scanner unit 100 that uses a lamp 102 to irradiate the document placed on the document platen glass with light and uses a line sensor 107 to receive the light reflected from the document, and thereby reads an image of the document; and a scanner controller that controls the scanner unit and generates an image signal representing the image based on a result of reading the image of the document performed by the scanner unit. When a plurality of documents are placed on the document platen glass, the scanner controller causes the scanner unit to irradiate the documents with light with any one of a first light quantity and a second light quantity reduced from the first light quantity based on the type of the plurality of documents.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image reading apparatus that reads an image from a document, and an image forming system including such an image reading apparatus and an image forming apparatus. [Background Art]

[0002] An image forming system including an image reading apparatus and an image forming apparatus can be used as a copying machine or a multifunction peripheral. In recent years, an image reading apparatus has implemented a function of placing a plurality of documents on a platen glass, reading images of the plurality of documents at one time, and outputting a plurality of image signals each individually representing an image of each document. The edges of the image of each document are extracted so that the image is not determined as an integrated image together with images of other documents. Such a function is called a "multi-crop function".

[0003] The multi-crop function enables reading of respective images of a plurality of small-sized documents at one time. When a thin and lightweight document such as a receipt is placed on the platen glass, curling or wrinkling may cause the document to lift off the platen glass. For this reason, the platen glass is provided with an openable and closable pressure plate. A document on the platen glass is pressed by the pressure plate, so that curling and wrinkling are prevented when the image of the document is read.

[0004] However, closing the pressure plate may make it difficult to extract the edges of a document image. In order to facilitate extraction of the edges of a document image, an image reading apparatus has been proposed that reads a document image by suppressing the amount of light irradiated when reading the document (Patent Document 1). In the present specification, such a method of reading a document image with suppressed light amount is referred to as "dark reading". [Prior Art Literature] [Patent Literature]

[0005] [Patent Document 1] Japanese Unexamined Patent Publication No. 2019-205110 [Summary of the Invention] [Problems that the invention aims to solve]

[0006] In multi-cropping, dark scanning is advantageous because it allows scanning multiple documents placed on the document glass at once and extracting images from each document. However, the scanned image obtained through dark scanning is generally dark, resulting in a loss of information in images that are close to black. Consequently, the tonal reproduction (the characteristic of reproducing the tonal range relative to the original image) of images such as photographs scanned through dark scanning is reduced. In other words, when scanning multiple documents including photographs using multi-cropping, the image quality of the scanned photographs will be reduced.

[0007] The decrease in tonal reproduction is particularly noticeable in areas with a black-to-white gradient. In dark scanning, the overall brightness of the scanned image decreases, causing the white areas of the original to appear slightly gray and the black areas to appear a deeper black due to the reduced tonal reproduction. As a result, in dark scanning, the dynamic range of brightness that the image reader can read becomes narrower, reducing the number of brightness gradations that can be sampled, and colors close to black in the scanned image are lost. For example, when scanning an 8-gray image in dark, the narrower dynamic range results in a 2-gray scanned image, and the gray image becomes a black scanned image. Since the black scanned image is not reproduced, there is a loss of information on the black side.

[0008] Furthermore, when the original document is a photograph, photographic paper has a higher basis weight and is thicker than regular paper, which makes it more likely for shadows to appear at the edges of the scanned image. Therefore, when extracting the edges of the scanned image, image processing such as edge enhancement can be used to accurately extract the edges. However, to avoid a decrease in tonal gradation, photographs must be scanned with sufficient light without reducing the amount of light illuminating the original document.

[0009] Thus, image reading devices need to switch the amount of light irradiated onto a document when reading it, depending on the type of document being read. In view of the above problems, the main objective of the present invention is to provide an image reading device that can read images from a document under optimal conditions according to the type of document. [Means for solving the problem]

[0010] The image reading device of the present invention comprises a document glass on which a document is placed, and a device that irradiates light onto the document placed on the document glass. Light-emitting part and , Irradiated light It receives the reflected light. It comprises a light receiving unit. , read the image of the aforementioned document Read means and before Note Read The system comprises control means for generating an image signal representing the image based on the result of reading the image of the document by means, and the control means is Multiple sheets manuscript If multi-crop mode is enabled, which reads all at once, , the aforementioned multiple manuscripts The first Types If so , the above Light-emitting part 1st light amount Make it light up , If the aforementioned multiple documents are of a second type different from the first type, the light-emitting unit The first light intensity less 2nd light amount Emits light It is characterized by causing this. The present invention provides an image forming system comprising: an image forming apparatus for forming an image on a sheet; and an image reading apparatus for reading an image from a document and generating an image signal representing the read image. The image forming apparatus acquires the image signal from the image reading apparatus and forms an image on the sheet based on the acquired image signal. The image reading apparatus comprises: a document glass on which a document is placed; a light-emitting unit for irradiating the document placed on the document glass with light; and a light-receiving unit for receiving reflected light from the irradiated light. The system also comprises: a reading means for reading an image from the document; and a control means for generating an image signal representing the image based on the reading result of the reading means. The control means is characterized in that, when a multi-crop mode for reading multiple documents at once is enabled, if the multiple documents are of a first type, the light-emitting unit emits light at a first light intensity; and if the multiple documents are of a second type different from the first type, the light-emitting unit emits light at a second light intensity less than the first light intensity. [Effects of the Invention]

[0011] According to the present invention, it is possible to read an image from a document under optimal conditions depending on the type of document. [Brief explanation of the drawing]

[0012] [Figure 1] A diagram illustrating the configuration of an image forming system. [Figure 2] (a) and (b) are diagrams illustrating the configuration of the image reading device. [Figure 3] Diagram illustrating the scanner controller. [Figure 4] (a) and (b) are diagrams illustrating the decrease in gradation reproduction due to reading from memory. [Figure 5]Figs. 1(a) and 1(b) are illustrative diagrams of a setting screen. [Figure 6] Figs. 3(a) and 3(b) are explanatory diagrams for a case where a thick document is read. [Figure 7] A flowchart illustrating a reading operation. [Figure 8] Figs. 9(a) to 9(c) are explanatory diagrams of a registration screen. [Figure 9] An illustrative diagram of configurable document sizes. [Figure 10] An explanatory diagram of a plurality of documents placed on a platen glass. MODE FOR CARRYING OUT THE INVENTION

[0013] Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

[0014] FIG. 1 is a configuration diagram of an image forming system including the image reading apparatus and the image forming apparatus of the present embodiment. An image forming system 1001 is configured by mounting an image reading apparatus 1005 on an image forming apparatus 1001A, and is implemented by, for example, a copier, a multifunction peripheral, an MFP (Multi Function Peripheral), or the like. The image forming system 1001 includes an operation display unit described later as a user interface including an input interface and an output interface.

[0015] The image reading apparatus 1005 includes a scanner unit 100 and a pressure plate 109. The pressure plate 109 is attached to the scanner unit 100 so as to be openable and closable. The scanner unit 100 optically scans a document to read an image from the document. The image reading apparatus 1005 transmits an image signal representing the read image of the document to a control unit 1032 of the image forming apparatus 1001A. The image forming apparatus 1001A forms an image on a sheet P, which is a recording medium, based on the image signal acquired by the control unit 1032.

[0016] The image forming apparatus 1001A comprises an image forming unit 1033 for forming an image on a sheet P, a sheet feeding unit 1006 for feeding the sheet P to the image forming unit 1033, and a fuser 1029. The sheet P is transported from the sheet feeding unit 1006 to the image forming unit 1033 where the image is transferred, and then the image is fixed by the fuser 1029 before being discharged to the discharge tray 1030.

[0017] The sheet feeding unit 1006 is equipped with multiple sheet storage units 1037a, 1037b, 1037c, and 1037d, each capable of storing sheets P of different sizes. Sheets P stored in each sheet storage unit 1037a, 1037b, 1037c, and 1037d are fed from the sheet storage units 1037a, 1037b, 1037c, and 1037d by the corresponding pickup rollers 1002a, 1002b, 1002c, and 1002d. The fed sheets P are separated one by one by the corresponding feed rollers 1003a, 1003b, 1003c, and 1003d, and retard rollers 1004a, 1004b, 1004c, and 1004d, and then transported to the corresponding transport roller pair 1031. The sheet P is passed sequentially to a plurality of transport roller pairs 1031 arranged along the sheet transport path, and is then transported to a registration roller pair 1036 provided on the sheet transport path.

[0018] The sheet feeding unit 1006 also includes a manual feed tray 1037e. Sheets P placed on the manual feed tray 1037e by the user are fed into the image forming apparatus 1001A by the feeding roller 1038 and transported to the registration roller pair 1036.

[0019] The registration roller pair 1036 stops the leading edge of the sheet P to correct its skew. The registration roller pair 1036 resumes transporting the sheet P to the image forming unit 1033 in accordance with the progress of the toner image formation process by the image forming unit 1033.

[0020] The image forming unit 1033 in this embodiment is an electrophotographic apparatus equipped with a photosensitive drum 1021. The image forming unit 1033 may also be configured to form images using, for example, an inkjet method or an offset printing method.

[0021] The photosensitive drum 1021 is a drum-shaped photoreceptor having a photosensitive layer on its surface, and is rotatable around the drum axis in the direction of transport of the sheet P. A charger 1018, an exposure unit 1023, a developer unit 1024, a transfer charger 1025, a separation charger 1026, and a cleaner 1027 are arranged around the photosensitive drum 1021. The charger 1018 uniformly charges the surface of the photosensitive drum 1021. The exposure unit 1023 exposes the charged surface of the photosensitive drum 1021 based on an image signal input from an image reading device 1005 or the like, forming an electrostatic latent image on the photosensitive drum 1021.

[0022] The developer unit 1024 contains a two-component developer including toner and a carrier. The developer unit 1024 supplies charged toner to the photosensitive drum 1021, causing it to adhere to the electrostatic latent image. This develops the electrostatic latent image, forming a toner image on the surface of the photosensitive drum 1021. The toner image supported on the photosensitive drum 1021 is transferred to the sheet P by a bias electric field formed by the transfer charger 1025. The sheet P is transported from the registration roller pair 1036 to the transfer charger 1025 in accordance with the timing of the toner image formation.

[0023] The sheet P onto which the toner image has been transferred is separated from the photosensitive drum 1021 by the bias electric field formed by the separator charger 1026 and transported to the fuser 1029 by the pre-fixing transport unit 1028. In addition, any remaining toner or other deposits that were not transferred to the sheet P and remain on the photosensitive drum 1021 are removed by the cleaner 1027, so that the photosensitive drum 1021 can prepare for the next image formation operation.

[0024] The fuser 1029 grips and transports the sheet P using a pair of rollers. At this time, the fuser 1029 heats and pressurizes the sheet P, melting and fixing the toner image onto the sheet P. Image formation on the sheet P is completed when the toner image is fixed. The sheet P with the formed image is discharged via the discharge roller pair 1010 to the discharge tray 1030 which protrudes outward from the image forming apparatus 1001A.

[0025] When performing double-sided printing, a sheet P with an image formed on one side (the first side) is transported to the inversion unit 1039 after passing through the fuser 1029 in order to form an image on the other side (the second side). The sheet P is inverted in the inversion unit 1039 so that the image-forming surface is reversed from the first side to the second side, and then transported to the double-sided transport unit 1040. The double-sided transport unit 1040 transports the sheet P with the reversed image-forming surface to the registration roller pair 1036. The sheet P is then transported from the registration roller pair 1036 to the image-forming unit 1033 where an image is formed on the second side, and then discharged to the discharge tray 1030.

[0026] Figure 2 is an explanatory diagram of the configuration of the image reading device 1005. Figure 2(a) is a view of the image reading device 1005 from the front of Figure 1, and Figure 2(b) is a view of the image reading device 1005 from the left side of Figure 1.

[0027] The scanner unit 100 includes a scanner unit 101 with a lamp 102, a document glass 103, folding mirrors 104 and 105, a lens 106, and a line sensor 107 that converts the scanned image into an electrical signal. The scanner unit 100 also has a reflective sensor 108 that detects a document placed on the document glass 103. The pressure plate 109 is openable and closable relative to the document glass 103. The pressure plate 109 is closed when scanning a document, pressing and fixing the document on the document glass 103.

[0028] The scanner unit 101 illuminates the document placed on the document glass 103 with light from the lamp 102, which is the light source. The lamp 102 illuminates the document with light in a straight line in the depth direction as shown in Figure 2(a). The reflected light from the document is imaged onto the light-receiving surface of the line sensor 107 via the mirror, the folding mirrors 104 and 105, and the lens 106 inside the scanner unit 101. The line sensor 107 is a reading unit composed of multiple light-receiving elements arranged in a straight line in the depth direction as shown in Figure 2(a). The line sensor 107 converts the reflected light received by each light-receiving element into photoelectric signals to generate an analog reading signal, which is an electrical signal representing the read image.

[0029] In Figure 2(a), the direction of the arrangement of the light emitted by the lamp 102 and the light-receiving elements of the line sensor 107 are both in the depth direction of Figure 2(a). Therefore, the depth direction of Figure 2(a) is the main scanning direction of the scanner unit 100. The sub-scanning direction, which is perpendicular to the main scanning direction, is the left-right direction in Figure 2(a). The scanner unit 101 is movable in the sub-scanning direction, and when reading an image, it moves in the sub-scanning direction while illuminating the document with light.

[0030] A reference white plate 113 is provided on the document glass 103. The reference white plate 113 has a reference white surface on the scanner unit 101 side for image reading and a size indicator plate on the pressure plate 109 side. The end of the size indicator plate serves as a stopper portion 112 for placing the document in the sub-scanning direction. The stopper portion 112 is the base end position of the document in the sub-scanning direction.

[0031] The scanner unit 100 is equipped with detection sensors 110 and 111 for detecting the opening and closing angle of the pressure plate 109. Detection sensor 110 detects when the opening and closing angle of the pressure plate 109 is 25 degrees, and detection sensor 111 detects when the opening and closing angle of the pressure plate 109 is 5 degrees.

[0032] Figure 3 is an explanatory diagram of the scanner controller that controls the operation of the scanner unit 100. The scanner controller 200 is an information processing device equipped with a CPU (Central Processing Unit) 201, ROM (Read Only Memory) 202, and RAM (Random Access Memory) 203. The CPU 201 controls the operation of the scanner unit 100 by executing a computer program stored in the ROM 202. The RAM 203 provides a work area for when the CPU 201 performs processing.

[0033] The scanner controller 200 also includes a drive unit 204 for moving the scanner unit 101 in the sub-scanning direction, an analog processing unit 205, and an image processing unit 206. The drive unit 204 moves the scanner unit 101 under the control of the CPU 201 when reading an image. The analog processing unit 205 performs analog processing on the analog reading signal output from the line sensor 107 under the control of the CPU 201. Through processing by the analog processing unit 205, the analog reading signal is converted into a digital reading signal. The image processing unit 206 performs image processing on the digital reading signal output from the analog processing unit 205 under the control of the CPU 201 to generate an image signal representing the image of the original document.

[0034] A lamp 102, detection sensors 110 and 111, a reflective sensor 108, and a line sensor 107 are connected to such a scanner controller 200. The CPU 201 reads an image from the document by controlling the lamp 102 and the line sensor 107. The CPU 201 acquires detection results from the detection sensors 110 and 111 and the reflective sensor 108. The CPU 201 detects the opening and closing angle of the pressure plate 109 based on the detection results of the detection sensors 110 and 111. The CPU 201 can detect the presence or absence of a document on the document glass 103 based on the detection result of the reflective sensor 108. The size of the document on the document glass 103 can be automatically detected based on the detection result of the reflective sensor 108. By receiving multiple reflective sensors 108, the document size can be detected with higher accuracy.

[0035] The scanner controller 200 is connected to the controller unit 2000 in a communicative manner. In particular, the image processing unit 206 is directly connected to the controller unit 2000. The controller unit 2000 is the main control unit that controls the operation of the image forming system 1001. The scanner controller 200 performs document scanning operations in response to instructions from the controller unit 2000. For this purpose, the controller unit 2000 includes a CPU 2001, an operation display unit 2002, an image processing unit 2003, and an image memory 2004.

[0036] The CPU 2001 controls the operation of the image forming apparatus 1001A to perform the image forming process described above and form an image on the sheet P. The image processing unit 2003 acquires an image signal from the image processing unit 206 of the scanner controller 200 and performs image processing on the image signal according to the control of the CPU 2001. The processed image signal is stored in the image memory 2004. Based on the image signal stored in the image memory 2004, the CPU 2001 controls the operation of each component of the image forming apparatus 1001A to form an image on the sheet P based on the image signal.

[0037] As described above, the operation display unit 2002 is a user interface that transmits instructions and settings entered via the input interface to the CPU 2001, and can output various information via the output interface in accordance with the control of the CPU 2001. The output interface of the operation display unit 2002 also includes a display that shows a setting screen for making various settings.

[0038] When scanning an image of a document placed on the document glass 103, the CPU 201 first moves the scanner unit 101 by the drive unit 204 to a position where it can scan the reference white plate 113, and then scans the reference white plate 113. The CPU 201 lights up the lamp 102 when scanning the reference white plate 113 and causes the line sensor 107 to receive the reflected light from the reference white plate 113. The CPU 201 performs known shading correction based on the analog scan signal output from the line sensor 107 that represents the scan result of the reference white plate 113.

[0039] After shading correction, the CPU 201 moves the scanner unit 101 in the sub-scanning direction using the drive unit 204 with the lamp 102 lit, and reads the image of the document using the line sensor 107 with the stopper 112 as the base edge of the document.

[0040] The line sensor 107 transmits an analog reading signal representing the image of the scanned document to the analog processing unit 205. The analog processing unit 205 performs predetermined processing on the analog reading signal and converts it into a digital reading signal. The analog processing unit 205 transmits the generated digital reading signal to the image processing unit 206. The image processing unit 206 performs predetermined processing on the digital reading signal to generate an image signal representing the scanned image and transmits it to the controller unit 2000. When the image reading device 1005 is used as a standalone unit, the image signal is output to an external device such as a personal computer via a predetermined communication interface or a portable recording medium.

[0041] The controller unit 2000 performs predetermined image processing on the image signal acquired from the scanner controller 200 using the image processing unit 2003, and stores the processed image signal in the image memory 2004. When performing copying, the CPU 2001 controls each part of the image forming apparatus 1001A to print the image based on the image signal stored in the image memory 2004 onto the sheet P.

[0042] (Multi-crop function) The operation of the image reading device 1005 in multi-crop mode will now be described. In multi-crop mode, multiple documents are placed on the document glass 103, and the image of each document can be read individually in a single scanning operation. As a result, in multi-crop mode, multiple image signals are generated, each representing an individual image of the multiple documents.

[0043] The user places multiple documents on the document glass 103, closes the pressure plate 109, and instructs the user to perform multi-crop scanning using the operation display unit 2002. The CPU 2001 of the controller unit 2000 instructs the scanner controller 200 to perform multi-crop scanning in response to the scanning instruction received from the operation display unit 2002. As a result, the CPU 201 of the scanner controller 200 performs multi-crop scanning using the image reading device 1005.

[0044] The image reading device 1005 reads multiple documents placed on the document glass 103 at once and outputs multiple image signals representing each image. The reading range and image extraction range for the documents are the entire surface of the document glass 103. Analog reading data representing the reading result of the entire surface of the document glass 103 is converted into a digital reading signal by the analog processing unit 205 and transmitted to the image processing unit 206. The image processing unit 206 extracts each image of the multiple documents from the digital reading signal representing the image of the entire surface of the document glass 103 and generates an image signal for each image. In this way, a multi-crop reading process is performed.

[0045] In multi-crop scanning, dark scanning, which reduces the amount of light emitted from lamp 102 when scanning the document, is advantageous. However, dark scanning reduces tonal reproduction. Figure 4 is an explanatory diagram of the decrease in tonal reproduction due to dark scanning.

[0046] Figure 4(a) shows the brightness results of reading an image under normal lighting conditions and under low-light conditions (dark reading). In dark reading, the brightness is generally lower, with white areas of the original appearing slightly gray and black areas appearing as a darker black. Thus, in dark reading, the dynamic range of brightness that the image reader 1005 can read is narrowed, causing images that are black to be crushed. Figure 4(b) shows the number of gradations and the smoothness of the gradation. The gray image (dotted line area), which originally had 8 gradations, becomes black in dark reading because the dynamic range of brightness is narrowed (the number of gradations becomes 2). Images that have been crushed to black will not be reproduced on sheet P, for example, when copying.

[0047] If the original document is a photograph, the image quality will not be maintained unless tonal reproduction is preserved. For this reason, dark scanning is not appropriate when scanning photographs with multi-crop. Therefore, when scanning multiple original documents with photographs using multi-crop, it is better to use a normal scanning process with more light than dark scanning, rather than performing dark scanning.

[0048] Figure 5 is an example of a settings screen for configuring such a multi-crop mode. Figure 5(a) shows an example of the initial screen displayed on the operation display unit 2002. When the user selects the "Multi-Crop" button 501 from the initial screen using the operation display unit 2002, the display on the operation display unit 2002 transitions to the multi-crop settings screen shown in Figure 5(b).

[0049] The multi-crop settings screen displays options for the type of document used in the multi-crop operation. Since the document types available are text documents (containing text) and photographic documents (containing photographic images), the settings screen displays two selectable buttons: "Text Document" button 502 and "Photographic Document" button 503. The user selects either button using the operation display unit 2002, thereby selecting either "Text Document" or "Photographic Document" in multi-crop mode. For example, if at least one of the multiple documents is a photographic document, the user would select "Photographic Document."

[0050] When "Photo Original" is selected, the system can read the photo original optimally by not performing a dark scan, taking into account the thickness and tonal range of documents such as photographs, business cards, and driver's licenses. In other words, photo originals are selected when the paper thickness of the sheet used for the original is greater than the specified paper thickness and it is necessary to maintain the image quality of the scanned image. When "Text Original" is selected, the system can properly read the outline of the original by performing a dark scan while holding down the lifting and movement of thin or curled documents such as receipts. In other words, text originals are selected when the paper thickness of the sheet used for the original is less than the specified paper thickness.

[0051] Furthermore, because documents such as photographs, business cards, and driver's licenses have thickness, a distance equal to the thickness of the document is created between the pressure plate 109 and the document glass 103. This results in a shadow of the document's outline being cast between the pressure plate 109 and the document glass 103. Figure 6 is an explanatory diagram for scanning thick documents.

[0052] Figure 6(a) shows a state in which a gap equal to the thickness of the document D is created between the pressure plate 109 and the document glass 103. The scanner unit 101 has two lamps 102: a lamp 102a that illuminates from the right and a lamp 102b that illuminates from the left. In this case, the light from lamp 102a, which is the light source on the right, illuminates the left side of the document D, but since the left contour of the document D is not illuminated, a shadow is created on the left side. Similarly, when the scanner unit 101 moves in the sub-scanning direction to read the document D, the light from lamp 102b, which is the light source on the left, illuminates the right side of the document D, but since the right contour of the document D is not illuminated, a shadow is created on the right side.

[0053] Figure 6(b) illustrates the shadows that occur along the contours of the photographic original in the state shown in Figure 6(a). Even when dark scanning is not performed on the photographic original, contours can be extracted from the scanned image by applying image processing such as edge enhancement to the shadows that occur along the contours. In this case, the image processing for edge enhancement involves, for example, making the gradient of the image density in the contour areas of the scanned image steeper to sharpen the contour areas of the scanned image.

[0054] In multi-crop mode, the document scanning operation is performed with the pressure plate 109 closed. This prevents the light from the lamp 102, which is used to scan the image from the document, from shining onto the user through the document glass 103.

[0055] After the user sets the type of document to be scanned using the multi-crop function on the settings screen shown in Figure 5(b), they place the document on the document glass 103 and instruct the operation display unit 2002 to start scanning the document. The CPU 2001 then retrieves information representing the set document type from the operation display unit 2002, stores it in the RAM 203, and the image reader 1005 performs the scanning operation corresponding to the setting.

[0056] Figure 7 is a flowchart illustrating the scanning operation by the image reading device 1005. This process begins when the user places a document on the document glass 103 and instructs the operation display unit 2002 to start scanning the document.

[0057] The CPU 2001 checks whether multi-crop mode is set (S601). If multi-crop mode is not set (S601:N), the CPU 2001 reads the image of the document with the normal light intensity setting (S604). When reading an image of a document with the normal light intensity setting, the size of the document is set before reading begins by automatic detection of the size of the document placed on the document glass 103 or by input using the user operation display unit 2002. Automatic detection of the size of the document is performed, for example, based on the detection result of the reflective sensor 108. For this reason, the range in which the image will be read is determined at the start of reading. The CPU 2001 reads the image of the document within the determined image reading range.

[0058] If multi-crop mode is set (S601:Y), CPU2001 temporarily invalidates the image scanning range that is normally determined before scanning begins (S602). This is because, in multi-crop mode, the entire surface of the document glass 103 is used as the scanning range. For this reason, the user may place multiple documents at any position on the document glass 103. CPU2001 checks whether the document to be scanned is set to be a photograph or a text document (S603).

[0059] When set to photographic document (S603:Y), CPU2001 does not perform dark scanning to read multiple documents, including thick documents such as photographs, business cards, and driver's licenses. By not performing dark scanning, photographic documents can be scanned under conditions optimal for extracting the outlines of the images in the documents. In this case, CPU2001 scans the images of the documents with the normal light intensity setting (S606).

[0060] When set to read text documents (S603:N), CPU2001 performs dark scanning to read multiple documents, including documents made of thin sheets such as receipts. Dark scanning allows for optimal conditions for extracting the outlines of the document image while suppressing curling, lifting from the document glass 103, and movement of the document. In this case, CPU2001 reads the image of the document with a dark scanning setting that reduces the amount of light compared to normal (S605).

[0061] As described above, the amount of light emitted when scanning a document is set to the normal amount of light (first light intensity) when not using multi-crop, or when scanning a document using a thick sheet such as a photograph with multi-crop. When scanning a document using a thin sheet such as a receipt with multi-crop, the light intensity is set to a reduced amount of light (second light intensity) from the normal amount.

[0062] In multi-crop mode, when scanning photographic documents, the document size in the scanned image is set according to the size of the document, without performing a blackout scan. In multi-crop mode, when scanning photographic documents, the entire surface of the document glass 103 is scanned, and the contours of each document are detected by performing image processing such as edge enhancement on the scanned image of the entire surface. In addition, by specifying the size of the document to be extracted in the default settings, it is possible to reliably extract the image of the document. The following describes how to specify the size of a photographic document.

[0063] Figure 8 is an explanatory diagram of the registration screen for registering the size of the document to be extracted in multi-crop mode. Each screen is displayed on the operation display unit 2002 by the CPU 2001. Figure 8(a) shows the initial setup / registration screen, illustrating the items that can be set / registered in the image forming system 1001. When the user selects the "Scan Specification Settings" button 701 from the initial setup / registration screen, the scan specification settings screen shown in Figure 8(b) is displayed. When the user selects the "Multi-Crop Settings" button 702 from the scan specification settings screen, the multi-crop settings screen shown in Figure 8(c) is displayed.

[0064] The multi-crop settings screen allows you to set the supported document size 703 for scanning documents using multi-crop. Figure 9 shows an example of the document sizes that can be set for supported document size 703. With supported document size 703, you can register which standard size the document to be scanned is. Figure 9 shows the options displayed for supported document size 703 and a list of the internal information set when each option is selected. For example, if L size is selected, the internal information will be set as W (length of the long side) = 127 [mm] and H (length of the short side) = 89 [mm].

[0065] Figure 10 is an explanatory diagram of multiple documents placed on the document glass 103. When scanning multiple documents at once using multi-crop, the range of each document is extracted from the scanned image through image processing, and an image signal representing the image of each document is output. At this time, if the corresponding document size 703 is set on the screen shown in Figure 8(c), the CPU 2001 extracts an image of the set document size from the scanned image. For example, if L-size is set, the CPU 2001 extracts an L-size (127 [mm] × 89 [mm]) image from the scanned image. The CPU 2001 also processes other documents in the same way, extracting images in the selected corresponding document size 703.

[0066] In the example above, the image of the original document to be extracted is set in advance by setting the size in multi-crop mode from the operation display unit 2002, but there may be other methods for setting the extraction range of the original image. For example, the extraction range of the original image may be set based on the model number information of commercially available photographic paper or photo paper used for the original photograph. Alternatively, the original image may be extracted by actually placing the original photograph on the document glass 103 and measuring the external dimensions of the original photograph itself.

[0067] The image reading device 1005 of this embodiment, as described above, performs reading processing without dimming the light intensity when reading documents that require maintaining image quality, such as photographic documents, using multi-crop scanning. When reading documents that do not require high image quality, such as text documents, using multi-crop scanning, it performs reading processing by dimming the light intensity compared to normal image reading. By changing the light intensity according to the type of document in this way, even with multi-crop scanning, images can be read from documents under optimal conditions, whether the document is intended for edge detection or requires consideration of tonal gradation.

[0068] The operation display unit 2002 may be provided on the image reading device 1005 side. In this case, the image reading device 1005 functions, for example, as a standalone scanner. Alternatively, the operation display unit 2002 may be provided on an external device connected to the image forming system 1001 via a network.

Claims

1. The document glass on which the document is placed, A reading means comprising a light-emitting unit that illuminates the document placed on the document glass and a light-receiving unit that receives the reflected light of the illuminated document, and for reading the image of the document, The system includes a control means that generates an image signal representing the image based on the reading result of the reading means of the original document, The control means is characterized in that, when the multi-crop mode for scanning multiple documents at once is enabled, if the multiple documents are of a first type, the light-emitting unit emits light at a first light intensity, and if the multiple documents are of a second type different from the first type, the light-emitting unit emits light at a second light intensity which is less than the first light intensity. Image reading device.

2. The second type of original document is characterized in that it is thinner than the first type of original document. The image reading device according to claim 1.

3. The second type of manuscript is a text manuscript, and the first type of manuscript is a photographic manuscript. The image reading device according to claim 1.

4. The control means is characterized in that, when the multi-crop mode is not enabled, the light-emitting unit emits light at a first light intensity. The image reading device according to claim 1.

5. The system further includes an input means for specifying the type of document, The control means is characterized in that it causes the light-emitting unit to emit light at either the first light intensity or the second light intensity based on the type of document instructed by the input means. The image reading device according to claim 1.

6. The control means is characterized in that it causes the light-emitting unit to emit light at a first light intensity when the paper thickness of the sheet used for the original document is greater than a predetermined paper thickness, and causes the front light-emitting unit to emit light at a second light intensity when the paper thickness of the sheet used for the original document is less than the predetermined paper thickness. The image reading device according to claim 1.

7. The control means is characterized in that it causes the light-emitting unit to emit light at a first light intensity when a photographic image is printed on the original document, and causes the light-emitting unit to emit light at a second light intensity when characters are printed on the original document. The image reading device according to claim 1.

8. The control means is characterized by generating a plurality of image signals representing each image of the plurality of documents from the reading results of the plurality of documents by the reading means. The image reading device according to claim 1.

9. The control means is characterized by extracting each image from the reading results of the plurality of documents and generating a plurality of image signals representing the extracted images. The image reading device according to claim 8.

10. The system further includes an input means for specifying the size of the aforementioned document. The control means is characterized by extracting each image from the scan results of the plurality of documents according to the specified size. The image reading device according to claim 9.

11. The input means is characterized by being able to specify a fixed size. The image reading device according to claim 10.

12. The system further includes a pressure plate that can be opened and closed relative to the document glass, The pressure plate is characterized in that it closes when scanning the document and presses down on the document placed on the document glass. The image reading device according to claim 1.

13. An image forming apparatus that forms an image on a sheet, It includes an image reading device that reads an image from a document and generates an image signal representing the read image, The image forming apparatus acquires the image signal from the image reading device and forms an image on the sheet based on the acquired image signal. The aforementioned image reading device is The document glass on which the document is placed, A reading means comprising a light-emitting unit that illuminates the document placed on the document glass and a light-receiving unit that receives the reflected light of the illuminated document, and for reading the image of the document, The system includes a control means that generates an image signal representing the image based on the reading result of the reading means of the original document, The control means is characterized in that, when the multi-crop mode for scanning multiple documents at once is enabled, if the multiple documents are of a first type, the light-emitting unit emits light at a first light intensity, and if the multiple documents are of a second type different from the first type, the light-emitting unit emits light at a second light intensity which is less than the first light intensity. Image forming system.

Images