JP2006025284A - Image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus capable of carrying out opening/closing detection of a sheet-through ADF with high accuracy without the need for using a particular detection means. <P>SOLUTION: The image reading apparatus provided with both a sheet-through reading system and a book reading system informs a control means 40 about an opening state of the ADF 6 in response to reading of a background board 18 in the sheet-through reading system. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus in an image forming apparatus including both a digital reading type copying machine and a facsimile, both having a sheet-through reading method and a book reading method.

In a digital reading type image reading apparatus, it has a light emitting means and a light receiving means for detecting opening and closing of a sheet through ADF (automatic document feeder), and the ADF opening and closing detecting means detects a reflected light to the ADF, and a closed position It is known to detect the middle position of the open position (see, for example, Patent Documents 1 and 2).
In these examples, in order to detect the open / closed state of the original platen also serving as the ADF, a detection unit different from the image reading unit is provided.
JP 2001-197263 A JP 2002-165074 A

Although it is often performed to detect the open / closed state by providing a sensor in the vicinity of the hinge of the original platen also serving as the ADF, it is difficult to detect the slightly opened state. There is a case where the ADF is slightly opened and an original jam occurs when trying to perform sheet-through reading with a thick book original placed.
In some cases, glass stains are detected and a warning is issued or the reading position is moved. In that case, if the ADF is not closed, the white on the background plate cannot be read. It cannot be detected correctly. There is a need for a method for detecting whether the ADF is properly closed.
SUMMARY OF THE INVENTION An object of the present invention is to provide an image reading apparatus that accurately performs opening / closing detection of a sheet through ADF without using a special detection means.

In order to solve the above-mentioned problems, the invention described in claim 1 is directed to an apparatus main body having a contact glass on the upper surface and having a reading unit directly below the contact glass, and an automatic pivotally supported by the upper surface of the apparatus main body so as to be opened and closed. In an image reading apparatus that includes a document supply device and a control unit, and is capable of performing both a sheet-through reading method and a book reading method, an open / close detection unit that detects a slight open state of the automatic document supply device, The control means determines that the automatic document feeder is in an open state based on the open detection information from the open / close detection means.
According to a second aspect of the present invention, in the image reading apparatus according to the first aspect of the present invention, the open / close detection means is an illumination for illuminating the background plate. Brightness reading means for reading the brightness of the background plate illuminated by the illumination means, and detection means for determining that the data read from the background plate is below a certain level, the control means comprising the data Is less than a certain level, it is determined that the automatic document feeder is in an open state.
According to a third aspect of the present invention, in the image reading apparatus according to the first aspect, in which the document positioned between the contact glass and the background plate is read by the reading unit at the time of reading, the open / close detection means is provided on the apparatus main body frame. Markings, markings provided on the background plate, reading means for reading each marking, and inter-marking distance judging means for judging the distance between the markings from the read data. The control means sets the distance between the markings in advance. If the measured value is not satisfied, it is determined that the automatic document feeder is in an open state.
According to a fourth aspect of the present invention, in the image reading apparatus according to the first aspect, in which the document positioned between the contact glass and the background plate is read by the reading unit at the time of reading, the open / close detection means is provided on the background plate. A caterpillar pattern, a pattern reading unit that reads the caterpillar pattern, and a contrast ratio pursuit unit that obtains a contrast ratio from the read data. The control unit automatically feeds an original document when the contrast ratio is less than a certain value. It is characterized in that it is determined that the paper device is in an open state.
According to a fifth aspect of the present invention, there is provided an image forming apparatus including the image reading apparatus according to any one of the first to fourth aspects.

Since the open / closed state of the ADF can be detected from the image data obtained by the image reading means, no dedicated detection means is required. Depending on the open / closed state of the ADF, the operation of the apparatus can be stopped to prevent troubles.
Moreover, since the open / closed state of the ADF can be detected by the distance between the markings, it is possible to detect the open / close with high accuracy. Furthermore, since the open / closed state of the ADF can be detected by the caterpillar pattern MTF, it is possible to detect the open / close with high accuracy. It can also be detected by a system that does not have an angle of view, such as a 1 × sensor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic sectional view showing an embodiment of an image reading apparatus according to the present invention. FIG. 2 is a schematic diagram showing the first embodiment of the ADF (automatic document feeder) of FIG. 1 in a simplified manner.
In the present embodiment, documents are conveyed one by one by an ADF (automatic document feeder) 6 and an image is read while passing over the contact glass 2 of the reader (main body) 1. Reading of an image is performed by the reading unit 1a. The ADF 6 is pivotally supported by a hinge portion provided on the back side of the upper surface of the apparatus body 1 so as to be opened and closed in the vertical direction.
The ADF 6 includes a document setting table 8 on which documents P are set in a stacked state, a sheet feeding roller 9, a conveyor belt 10, a conveyor belt 1, a conveyance path 17, a pair of sheet feeding rollers 14a and 14b, a background plate 18 (sheet through 18a, 18b), a paper discharge guide 20, paper discharge rollers 19a, 19b, 21a, 21b, a paper discharge tray 22, and the like. The contact glass 2 is for a sheet through reading method, and the contact glass 3 is for a reading method (including book reading) in a state where the original is stationary and the reading optical system is moved.
The image on the document P fed to the reading position is illuminated by the illuminating means 4 and forms an image on the CCD 37 through the mirrors 33, 34, 35 and the lens 36 of the reading unit 1a. The image data captured by the CCD 37 is subjected to image processing and then sent to the printer unit for output.
The sheet-through background plate 18a is disposed opposite to the position above the contact glass 2 with a predetermined gap, and has a function of securing a document transport path. In the present invention, the background plate 18a has a color with high reflectance (for example, white). As shown in FIG. 2, the background plate 18a has a different structure from the background plate 18 of FIG. When the ADF 6 is slightly opened, the background plate 18a and the reading unit 1 are separated.
In particular, the distance increases on the side far from the opening / closing fulcrum of the ADF (L2> L1). In this state, when the illumination unit 4 is turned on and an image is read, the image data becomes brighter on the fulcrum side of the ADF and becomes darker as the distance from the fulcrum 6a increases.
The configuration for detecting opening and closing in the above-described embodiment and the following embodiments can also be applied to the relationship between the book background plate 18b and the book contact glass 3.
FIG. 3 is a block diagram schematically showing the control system of the first embodiment in FIG. As described above, the image reading apparatus having both the sheet-through reading method and the book reading method includes the illumination unit 4 that illuminates the background plate 18a for sheet-through reading from the reading unit 1 side.
Brightness reading means (opening / closing detection means) 38 for reading the brightness of the background plate 18a for sheet-through reading, and detection means 39 for determining that the data read from the background plate 18a is below a certain level are provided. If the level is below a certain level, the control means 40 is informed that the ADF 6 is open.
This embodiment can also be applied to the book reading background plate 18b.

FIG. 4 is a graph showing image reading data in the closed state and the opened state of the ADF. As shown in the figure, when the ADF is open, the image data level decreases on the side away from the fulcrum. It is determined from this data that the ADF is open.
ADF opening / closing detection may be determined from data on the side away from the fulcrum 6a, or may be determined on the side close to the fulcrum. Further, the opening / closing angle can be more accurately determined by combining both data.
When it is detected that the ADF is in an open state, for example, the document feeding operation can be stopped to prevent document conveyance jam. Also, when detecting dust on the reading line and giving a warning or moving the reading position, if the ADF is not properly closed, the operation is stopped to prevent false detection. can do.
FIG. 5 is a schematic diagram showing a second embodiment of the ADF (automatic document feeder) of FIG. 1 in a simplified manner. In the present embodiment, a marking A is provided on the main body frame side of the reading device 1, and a marking B is provided on the background plate 18.
The marking A may be on, for example, the contact glass 2 or on the outer frame thereof. In the case of the reduction optical system, since there is a field angle of the lens, the marking position is shifted on the read image data when it is separated from the original surface.
When the ADF 6 is closed, the distance between the marking A and the marking B is LA, but when the ADF is open, the distance is LB. The marking distance LA when the ADF 6 is closed may be determined by design dimensions, or may be determined by taking in data after the apparatus is assembled.
This embodiment can be applied to both sheet-through and book reading.
FIG. 6 is a block diagram schematically showing the control system of the second embodiment in FIG. According to the present embodiment, the image reading apparatus having both the sheet-through reading method and the book reading method includes a marking A provided on the main body frame, a marking B provided on the background plate 18 for sheet-through reading, A marking reading means 41 for optically reading these markings is provided. The markings A and B and the marking reading means 41 constitute an open / close detection means.
Further, the image reading apparatus includes an inter-marking distance determining means 42 for determining a distance between markings from the read data, and when the distance between the markings deviates from a preset value, the ADF 6 is opened. Tell the control means 40 that there is.

FIG. 7 is a schematic diagram showing a simplified third embodiment of the ADF (automatic document feeder) of FIG. In the present embodiment, the background plate 18 is provided with a caterpillar stripe pattern.
This embodiment can be applied to both sheet-through and book reading.
When the ADF 6 is closed, the background plate 18 is in focus, so that the white and black portions of the pattern can be clearly recognized. Eventually, only gray will be recognized.
When such a pattern is read, the MTF can be obtained from the level difference between the white portion and the black portion of the pattern, but the distance to the background plate 18 can be estimated from the value, and the opening / closing amount of the ADF 6 can be determined. In FIG. 7, the pattern is provided on the side away from the opening / closing fulcrum 6a of the ADF 6, but it may be provided on the side close to the fulcrum. The side farther from the fulcrum can be reliably detected with a smaller opening / closing amount.
FIG. 8 is a block diagram schematically showing the control system of the third embodiment in FIG. The image reading apparatus having both the sheet-through reading method and the book reading method includes a caterpillar pattern C provided on the background plate 18 for sheet-through reading, and a pattern reading unit 43 that reads the caterpillar pattern C. ing. The pattern C and the pattern reading unit 43 constitute an open / close detection unit.
Furthermore, a contrast ratio pursuit means 44 for obtaining a contrast ratio from the read data is provided, and when the contrast ratio is equal to or smaller than a certain value, the control means 40 is informed that the ADF 6 is in an open state.

1 is a schematic cross-sectional view showing an embodiment of an image reading apparatus according to the present invention. FIG. 2 is a schematic diagram illustrating a first embodiment of the ADF (automatic document feeder) of FIG. 1 in a simplified manner. FIG. 3 is a block diagram schematically showing a control system of the first embodiment in FIG. 2. It is a figure which shows the image reading data in the state where ADF was closed and the state opened. FIG. 5 is a schematic diagram showing a second embodiment of the ADF (automatic document feeder) of FIG. 1 in a simplified manner. FIG. 6 is a block diagram schematically showing a control system of the second embodiment in FIG. 5. FIG. 6 is a schematic diagram showing a third embodiment of the ADF (automatic document feeder) of FIG. 1 in a simplified manner. FIG. 8 is a block diagram schematically showing a control system of the third embodiment in FIG. 7.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Image reading part, 4 Illumination means, 6 ADF (automatic document feeder), 18 Background board, 38 Brightness reading means, 39 Detection means, 40 Control means, 41 Marking reading means, 42 Inter-marking distance judgment means, 43 patterns Reading means, 44 Contrast ratio pursuit means, A marking (provided on the body frame), B marking (provided on the background board), C Caterpillar pattern (provided on the background board)

Claims (5)

An apparatus main body having a contact glass on the upper surface and having a reading unit directly below the contact glass, an automatic document feeder supported in an openable and closable manner by the upper surface of the apparatus main body, and a control means. In an image reading apparatus capable of performing both reading methods,
Open / close detection means for detecting a slight open state of the automatic document feeder,
An image reading apparatus characterized in that the control means determines that the automatic document feeder is in an open state based on open detection information from the open / close detection means. In an image reading apparatus in which an original positioned between a contact glass and a background plate is read by a reading unit at the time of reading,
The open / close detection means includes an illumination means for illuminating the background board, a brightness reading means for reading the brightness of the background board illuminated by the illumination means, and a detection for determining that the data read from the background board is below a certain level. With means,
The image reading apparatus according to claim 1, wherein the control unit determines that the automatic document feeder is in an open state when the data is below a certain level. In an image reading apparatus in which a document located between a contact glass and a background plate is read by a reading unit at the time of reading,
The open / close detection means includes a marking provided on the apparatus main body frame, a marking provided on the background plate, a reading means for reading each marking, and an inter-marking distance determining means for determining a distance between markings from the read data.
The image reading apparatus according to claim 1, wherein the control unit determines that the automatic document feeder is in an open state when a distance between markings deviates from a preset value. In an image reading apparatus in which an original positioned between a contact glass and a background plate is read by a reading unit at the time of reading,
The open / close detection means includes a caterpillar pattern provided on a background plate, a pattern reading means for reading a caterpillar pattern, a contrast ratio pursuit means for obtaining a contrast ratio from the read data,
The image reading apparatus according to claim 1, wherein the control unit determines that the automatic document feeder is in an open state when the contrast ratio is a certain value or less.   An image forming apparatus comprising the image reading apparatus according to claim 1.

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