JP2014053772A - Image reader and image forming apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader which can easily detect white paper of a document including a ruled line such as a notebook.SOLUTION: An image reader includes: a light source for lighting an image face of a document placed on a table; an image-forming lens for image-forming reflected light from the document; a photoelectric conversion element for converting an optical image which is image-formed by the image-forming lens into an electric signal; a fixed reading mode for placing the document on the table and reading the image; and a book dividing/reading function which divides the document in a spread state into two to acquire two pages and deals individual pages as one sheet of the document. When the book dividing/reading function is performed at the time of the fixed reading mode, white paper is detected, and the white paper is not detected when the book dividing/reading function is not performed at the time of the fixed reading mode.

Description

  The present invention relates to an image reading apparatus for optically reading a document image and an image forming apparatus including the image reading apparatus.

  An image forming apparatus such as a copying machine that forms an image on a sheet by an electrophotographic method includes an image reading apparatus for optically reading a document image. The image reading apparatus is placed on a table. A light source that illuminates the image surface of the original, an imaging lens that forms an image of reflected light from the original, and a photoelectric conversion element such as a CCD that converts an optical image formed by the imaging lens into an electrical signal. It is configured to include. Such an image reading apparatus has a fixed reading mode in which an original is placed on a table and the image is read, and a continuous reading mode in which the image is read while continuously supplying the original one by one on the table. There is something to prepare.

  By the way, a document may include a blank document that does not include valid information, and when a series of image processing is performed on such a blank document by performing image reading, the output image includes a blank sheet. In addition to the need to remove this blank paper, there is a problem that image processing time is wasted.

  Therefore, Patent Document 1 discriminates black streaks caused by dust attached to the optical system and images such as ruled lines and tables on the original and accurately removes black streaks unrelated to the read image. An image reading apparatus that can be used has been proposed. Specifically, the binarized image data is added for one page in the sub-scanning direction, black stripes are detected based on the added data, and the intervals between the detected black stripes are approximately equal. If there is, or if the number of black pixels as the addition data is a substantially constant value, the black streak is determined to be an image such as a ruled line or table on the document, and black streak correction is not performed. In this case, black streak correction is performed.

  In Patent Document 2, the number of pixels in which pixels having a predetermined density or higher appear continuously in the image data is counted, and the image data is effective for the user based on the counted number of pixels and the type of document. An image processing apparatus that determines whether or not the image data has valid information, and outputs image data when it is determined that the image data has valid information; otherwise, the image data is not output An image processing method has been proposed.

JP 2004-328200 A JP 2010-068227 A

  However, since the configurations proposed in Patent Documents 1 and 2 also detect equidistantness in the direction orthogonal to the line having continuity, an area for storing the information is required, and the detection circuit is large. There is a problem of becoming.

  The configuration proposed in Patent Document 2 also has a problem that the circuit scale becomes large because a circuit for discriminating characters and pictures is necessary.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image reading apparatus capable of easily detecting a blank sheet of a document including ruled lines such as notes, and an image forming apparatus including the image reading apparatus. Is to provide.

In order to achieve the above object, the invention described in claim 1 includes a light source that illuminates an image surface of a document placed on a table, an imaging lens that forms an image of reflected light from the document, and the imaging lens. A photoelectric conversion element that converts an optical image formed by the above into an electrical signal, a fixed reading mode in which an original is placed on the table and the image is read, and a two-page original is divided into two pages. In an image reading apparatus having a book division reading function for handling each page as one original,
When the book division reading function is executed in the fixed reading mode, blank page detection is performed. On the other hand, when the book division reading function is not executed in the fixed reading mode, blank page detection is not performed. And

According to a second aspect of the present invention, in the first aspect of the invention, the blank sheet detection is performed by reading a document in which pixels having a density lower than a predetermined threshold are read by continuous pixels that are equal to or greater than a predetermined number of pixels in the main scanning direction. Done by determining whether it exists in the image data,
If it is determined in the blank page detection that the continuous pixels are not present in the document image data, it is detected that the document is blank.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, when a blank page is detected as a result of the blank page detection, the user is notified of this and the user is allowed to select whether or not to perform the printing process. It is characterized by that.

The invention according to claim 4 further comprises a flow reading mode in which the image is read while continuously supplying the document on the table in the invention according to any one of claims 1 to 3,
The blank sheet detection is performed in the flow-reading mode.

  An image forming apparatus according to a fifth aspect includes the image reading apparatus according to any one of the first to fourth aspects, and does not perform image processing on a read image in which blank paper is detected by the image reading apparatus. It is characterized by.

  According to the present invention, when reading a two-page spread document in the fixed reading mode, book split reading is performed and blank page detection is performed. In other cases, that is, when there is no possibility that the document is blank (for example, Since only one of the left and right pages of a two-page spread document is copied or when a single document is placed on a table and the image is read, the blank line is not detected. Can be easily detected. In the flow-reading mode, blank pages are detected because there is a possibility that blank pages are included in the document.

  Further, according to the present invention, since blank page detection is performed by detecting the number of pixels that are continuous in the main scanning direction, for example, when a notebook is placed so that its ruled line is orthogonal to the main scanning direction. The ruled line is not recognized as a pixel having continuity in the main scanning direction. For this reason, blank paper is detected based on image data such as characters and pictures other than the ruled lines. At this time, since the number of continuous pixels in the main scanning direction is counted, the regular spacing of the ruled lines in the sub-scanning direction, etc. Is unnecessary, and the circuit configuration is simplified.

  Further, according to the present invention, since the image processing and printing are not performed on the read image in which the blank page is detected by the image reading apparatus, it is not necessary to remove the blank sheet later, which is a burden on the user. Is reduced.

1 is a side sectional view of an image forming apparatus according to the present invention. 3 is a cross-sectional view in the sub-scanning direction of the image reading apparatus according to the present invention. FIG. (A), (b) is a top view which shows the aspect of the mounting state of the notebook on the table of an image reading apparatus. 6 is a flowchart showing a reading control procedure in the image reading apparatus according to the present invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

[Image forming apparatus]
FIG. 1 is a side sectional view of an image forming apparatus according to the present invention. The illustrated image forming apparatus 1 is a monochrome copying machine, and includes an image reading device 2 according to the present invention at the upper part of the apparatus main body 1A. A discharge tray 3 is provided below the discharge tray 3. An image forming unit 4 is disposed inside the apparatus main body 1A, and a paper feeding unit 5 is disposed below the image forming unit 4.

  The image forming unit 4 forms an image by an electrophotographic method. The image forming unit 4 is a photosensitive drum 6 as an image carrier arranged rotatably, a charger 7 arranged around the photosensitive drum 6, and a laser scanner unit ( LSU) 8, a developing device 9, a transfer roller 10, and a cleaning device 11.

  The paper feed unit 5 includes a detachable paper feed cassette 12 and a pick roller 13 and a paper feed roller 14 disposed in the vicinity thereof. Here, a plurality of sheets S are stacked and accommodated in the sheet cassette 12, and the sheets S in the sheet cassette 12 are sequentially picked up from the upper one by the pick roller 13, and are fed by the sheet feed roller 14. It is sent out to the paper conveyance path P.

  The paper transport path P extends upward from the paper supply unit 5 to the paper discharge tray 3, and the registration roller 15, the transfer roller 10, the fixing device 16, and the transport of the paper transport path P from below. A roller 17 and a paper discharge roller 18 are sequentially arranged.

  Next, an image forming operation of the image forming apparatus 1 configured as described above will be described.

  When the image forming operation is started, in the image forming unit 4, the photosensitive drum 6 is rotationally driven in the arrow direction (clockwise) in FIG. 1 by a driving unit (not shown), and the surface thereof is set to a predetermined potential by the charger 7. Uniformly charged. In the image reading device 2, the original image is read as described later, and a laser beam based on an electric signal transmitted from the image reading device 2 is output from the laser scanner unit 8 to expose the surface of the photosensitive drum 6. When scanned, an electrostatic latent image corresponding to image information is formed on the photosensitive drum 6. Then, the electrostatic latent image formed on the photosensitive drum 6 is developed by the developing device 9 using toner as a developer to be visualized as a toner image.

  Further, the paper S accommodated in the paper feed cassette 12 of the paper feed unit 5 is picked up from the uppermost one by the pick roller 13 and sent out to the paper transport path P by the paper feed roller 14. Then, the sheet S sent out to the sheet conveyance path P in this way is conveyed to the registration roller 15 through the sheet conveyance path P and is temporarily put in the registration roller 15, and then the toner on the photosensitive drum 6. The image is supplied to the image forming unit 4 at a predetermined timing synchronized with the image.

  In the image forming unit 4, the sheet S supplied to the transfer nip between the photosensitive drum 6 and the transfer roller 10 is conveyed while being pressed against the photosensitive drum 6 by the transfer roller 10, so that the surface thereof is exposed to light. The toner image on the drum 6 is transferred. Then, the sheet S on which the toner image is transferred is conveyed to the fixing device 16 and is heated and pressurized in the process of passing through the fixing nip of the fixing device 16 to receive the toner image. The toner remaining on the surface of the photosensitive drum 6 (transfer residual toner) after the transfer of the toner image onto the paper S is removed by the cleaning device 11, and the photosensitive drum 6 whose surface is cleaned is prepared for the next image forming operation. .

Thus, the sheet S having the toner image fixed on the surface thereof by the fixing device 16 is conveyed by the conveying roller 17 along the sheet conveying path P to the sheet discharging roller 18, and the sheet discharging tray 18 by the sheet discharging roller 18. 3 to complete the series of image forming operations.
[Image reading device]
Next, the configuration of the image reading apparatus 2 according to the present invention will be described with reference to FIG.

  FIG. 2 is a cross-sectional view of the image reading apparatus according to the present invention in the sub-scanning direction. The illustrated image reading apparatus 2 includes an optical frame 19 that is a box-like structure constituting a housing. A table (contact glass) 20 is provided on the upper surface. A white reference plate 21 is provided at the end of the table 20 to determine a white reference for the reading density. Although not shown, the image reading apparatus 2 according to the present embodiment has an automatic document conveying device (automatic document conveying device) that automatically conveys a plurality of documents stacked on the document tray one by one onto the table 20 one by one. ADF) is provided.

  The optical frame 19 accommodates first and second movable carriages 22 and 23 that are movable in the sub-scanning direction. Here, a plurality of LEDs 24 arranged in the main scanning direction (perpendicular to the paper surface of FIG. 2) are illuminated on the first moving carriage 22 to illuminate the document placed on the table 20, and reflected by the document. A first reflecting mirror 25 that reflects the reading light (reflected light) in the 90 ° direction is provided, and the second carriage 23 reflects the reflected light reflected by the first reflecting mirror 25 in the 90 ° direction. A second reflecting mirror 26 and a third reflecting mirror 27 for reflecting the reflected light reflected by the second reflecting mirror 26 in the direction of 90 °, and the first and second movable carriages 22 and 23 are provided. Then, it moves in the sub-scanning direction (left-right direction in FIG. 2) along a guide rail (not shown).

  Further, an imaging lens 28 and a CCD 29 as a photoelectric conversion element are coaxially arranged and accommodated inside the optical frame 19, and read light (reflective) from the original reflected by the third reflection mirror 27. After being converged by the imaging lens 28, the light enters the CCD 29 and forms an image on the CCD 29.

  Next, an image reading operation of the document reading apparatus 2 configured as described above will be described.

  In the image reading apparatus 2 according to the present embodiment, a document is manually placed on the table 20 one by one and the image is read, and the document is placed on a document tray (not shown). There is a flow reading mode in which an image is read while an original is continuously fed one by one onto the table 20 by an automatic document feeder (ADF).

  For example, when the fixed reading mode is selected as the image reading method, when the user places a document on the table 20 of the image reading apparatus 2 and operates a start switch (not shown), the image reading operation is started.

  That is, the document placed on the table 20 is moved while the first moving carriage 22 and the second moving carriage 23 shown in FIG. 2 move along a guide rail (not shown) in the sub-scanning direction (left-right direction in FIG. 2). When scanning, the light emitted from the LED 24 of the first moving carriage 22 is directed to the document, and the document is illuminated by this light. The light that illuminates the original is reflected by the original, and the reflected light is reflected by the first reflecting mirror 25 of the first moving carriage 22 in the 90 ° direction, and then the second reflecting mirror of the second moving carriage 23. 26 and the third reflecting mirror 27 are respectively reflected in the 90 ° direction to reach the imaging lens 29, converged by passing through the imaging lens 29, imaged on the CCD 30 and read by the CCD 30. It is converted into an electrical signal (analog signal). The analog signal read by the CCD 30 is digitally converted by an AFE (analog front end) (not shown) as an A / D conversion means, and as a result, document image data is generated.

  When the document image is optically read by the image reading apparatus 2 as described above, the electric signal is transmitted to the laser scanner unit 8 shown in FIG. 1, and the laser scanner unit 8 transmits laser light based on the electric signal. And the above-described image forming operation is performed in the image forming apparatus 1 shown in FIG. 1 to obtain a desired copy image.

  Thereafter, when the user opens the pressure plate (DP) and takes out the original, a series of image forming operations (copying operations) is completed.

  Next, the gist of the present invention will be described below with reference to FIGS.

  FIGS. 3A and 3B are plan views showing the state of the placement of the notebook on the table of the image reading apparatus, and FIG. 4 is a flowchart showing the reading control procedure in the image reading apparatus according to the present invention.

  In the image reading apparatus 2 according to the present embodiment, blank page detection is performed to detect whether or not a document is a blank page that does not contain valid information. This blank page detection has a density value (tone value) of a predetermined value. This is performed by detecting a pixel smaller than the threshold (hereinafter also referred to as a black pixel) by a control unit (not shown) of the image reading apparatus 2. Then, the control unit determines whether or not the black pixels are continuous for a predetermined number of pixels in the main scanning direction. In other words, the control unit is a black pixel that is continuous for a predetermined number of pixels in the main scanning direction (hereinafter also referred to as a continuous black pixel. The continuous black pixel constitutes a continuous pixel according to the present invention). Is present in the document image data.

  When it is determined that there are no continuous black pixels in the document image data, the control unit detects that the document is blank (including when black pixels are not detected). In other words, when continuous black pixels are detected by the control unit, it is considered that the document is not blank. Here, the predetermined pixel is set to be larger than the number of pixels corresponding to the thickness of the ruled line. For example, when the resolution in the main scanning direction of the scanner is 600 dpi and the thickness of the ruled line is 0.4 mm, the predetermined number of pixels is set to 10 pixels or more. The predetermined threshold value and the predetermined number of pixels may be stored in advance as fixed values in a storage unit (not shown) of the image reading device 2, or the user may display a display unit (not shown) of the image reading device 2. It may be possible to change as appropriate by operating the.

  In the present embodiment, the fixed reading mode is selected as the image reading method, and the notebook which is a spread document is spread as shown in FIG. 3A (the left and right spread pages can be copied). When placed on the table 20, the left and right facing pages are divided into two pages, and when the book division reading function that handles each page as one original is selected, blank page detection is performed for each original. Like that. That is, when the notebook is placed on the table 20 in a spread state as shown in FIG. 3A, there is a possibility that blank pages are included in either the left or right page. Blank page detection is performed in book division reading, which is handled as original documents one by one. In this case, as shown in FIG. 3A, the ruled lines of the notebook are not recognized as continuous black pixels that are orthogonal to the main scanning direction and are continuous in the main scanning direction. As described above, since the number of continuous black pixels in the main scanning direction is counted, a circuit for recognizing the equal spacing of ruled lines in the sub-scanning direction becomes unnecessary, and the circuit configuration is simplified.

  On the other hand, in the fixed reading mode, when the notebook is placed on the table 20 as shown in FIG. 3B in order to copy only one of the left and right pages of the notebook, the page to be copied Since there is no possibility that is a blank sheet, blank sheet detection is not performed. Further, even in the normal reading in which the user places the originals one by one on the table 20 and reads the images, there is no possibility that the originals contain white paper, so that the white paper is not detected. .

  Although the operation in the fixed reading mode has been described above, the originals stacked on a document tray (not shown) are automatically and continuously supplied one by one on the table 20 by an automatic document feeder (ADF). In the flow-reading mode in which the document is read, since there is a possibility that the document includes a blank page, blank page detection is performed.

  The reading control procedure described above will be described below based on the flowchart shown in FIG.

  When the image reading operation is started (step S1 in FIG. 4), it is determined whether the document reading mode is the fixed reading mode or the flow reading mode (step S2). If the document reading mode is the fixed reading mode, it is determined whether or not book division reading is selected (step S3). For example, as shown in FIG. When the divided book reading is selected (when the determination result in step S3 is Yes), blank page detection is performed (step S4). Further, as a result of the determination in step S2, blank sheet detection is also performed when it is determined that the document reading mode is the flow reading mode (step S4).

  If a blank page is detected in step S4, it is determined whether or not a blank page is detected (step S5). If no blank page is detected (if the determination result in step S5 is No), an image corresponding to the original is detected. Forming processing (copying processing) is performed (step S6), an image is printed on the paper (step S7), and a series of image forming operations is completed (step S8). On the other hand, if a blank sheet is detected (if the determination result in step S5 is Yes), the user is notified of this by a buzzer or lamp display (step S9), and the user is notified. Whether or not to perform image processing is selected, and the result is determined (step S10). If the user selects image processing (if the determination result in step S10 is Yes), the process proceeds to step S6, where the image processing is performed and an image is printed on the paper (step S7). The image forming operation ends (step S8). On the other hand, when the user does not select image processing (when the determination result in step S10 is No), image processing (step S6) and printing (step S7) are not performed on a blank document. A series of image forming operations ends (step S8). In this way, when the user does not want to perform image processing on blank paper, image processing and printing are not performed on the blank original, so that it is not necessary to remove the blank paper later, reducing the burden on the user. Is done.

  On the other hand, when the determination result in step S3 is No, that is, as shown in FIG. 3B, the notebook is placed on the table 20 as shown in order to copy only one of the left and right pages of the notebook. When a normal reading is performed by placing a normal original other than a spread original on the table 20 and performing normal reading, there is no possibility that the original contains a blank, so blank page detection is performed. Instead, the image forming process (step S6) and the printing (step S7) are executed on the document, and the series of image forming operations is completed (step S8).

  As described above, in the image reading apparatus 2 according to the present invention, when reading a two-page spread in the fixed reading mode, blank page detection is performed when book split reading is selected, and in other cases, that is, an original image blank sheet. (For example, when the notebook is placed on the table 20 as shown in FIG. 3B in order to copy only one of the left and right pages of the notebook which is a spread document, or 1 In the case of normal reading in which a single document is placed on the table 20 and reading the image), blank page detection is not performed, so that blank page detection of a document including ruled lines such as notes can be easily performed. it can.

  Further, since the blank page is detected by detecting the continuity of the black prime numbers in the main scanning direction, for example, when a notebook is placed on the table 20 as shown in FIG. These ruled lines are orthogonal to the main scanning direction and are not recognized as continuous black pixels having continuity in the main scanning direction. For this reason, when blank paper detection is performed based on image data such as characters and pictures other than the ruled lines, the number of continuous pixels is recognized, so that a circuit for recognizing equal spacing of ruled lines in the sub-scanning direction is not necessary. The circuit configuration is simplified.

  Further, in the image forming apparatus 1 shown in FIG. 1, image processing and printing are not performed on the read image that has been detected by the image reading device 2, so that there is no need to remove blank paper later. Thus, the burden on the user is reduced.

  In this embodiment, the embodiment in which the present invention is applied to a monochrome copying machine and an image reading apparatus provided in the monochrome copying machine has been described. However, the present invention is not limited to a monochrome or color facsimile machine other than a copying machine. Needless to say, the present invention can be similarly applied to any other image forming apparatus such as a multifunction peripheral and an image reading apparatus provided therein.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 1A Image forming apparatus main body 2 Image reading apparatus 3 Paper discharge tray 4 Image forming part 5 Paper feeding part 6 Photosensitive drum 7 Charger 8 Laser scanner unit (LSU)
DESCRIPTION OF SYMBOLS 9 Developing device 10 Transfer roller 11 Cleaning device 12 Paper feed cassette 13 Pick roller 14 Paper feed roller 15 Registration roller 16 Fixing device 17 Conveyance roller 18 Paper discharge roller 19 Optical frame 20 Table 21 White reference plate 22 First moving carriage 23 Second Moving carriage 24 LED (light source)
25 First Reflection Mirror 26 Second Reflection Mirror 27 Third Reflection Mirror 28 Imaging Lens 29 CCD (Photoelectric Conversion Element)
P Paper transport path S Paper

Claims (5)

A light source that illuminates an image surface of a document placed on a table, an imaging lens that forms an image of reflected light from the document, and a photoelectric conversion that converts an optical image formed by the imaging lens into an electrical signal A fixed reading mode that includes an element and places an original on the table and reads the image; and a book division reading function that divides a two-page spread into two pages and treats each page as one original In an image reading apparatus comprising:
When the book division reading function is executed in the fixed reading mode, blank page detection is performed. On the other hand, when the book division reading function is not executed in the fixed reading mode, blank page detection is not performed. An image reading apparatus. The blank page detection is performed by determining whether or not pixels having a density lower than a predetermined threshold are present in the read document image data by continuous pixels that are continuous in the main scanning direction by a predetermined number of pixels or more. ,
2. The image reading apparatus according to claim 1, wherein when it is determined in the blank page detection that the continuous pixels are not present in the document image data, it is detected that the document is a blank sheet.   3. The image reading apparatus according to claim 1, wherein when a blank page is detected as a result of the blank page detection, the user is notified of this and the user is allowed to select whether or not to perform a printing process. A flow reading mode for reading the image while continuously supplying the document on the table;
The image reading apparatus according to claim 1, wherein the blank sheet is detected in the flow reading mode. An image forming apparatus comprising: the image reading apparatus according to claim 1, wherein image processing is not performed on a read image in which blank paper is detected by the image reading apparatus.

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