JP4443166B2 - Document reading apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image reading apparatus provided in an image forming apparatus such as a copying machine, a facsimile, or the like that can be read by pressing a thick original such as a book on a contact glass with a pressure plate, ADF, or the like. The present invention relates to a reading device.

  In order to detect the size of a document placed on the contact glass, a conventional document reading apparatus is provided with a document size detection sensor disposed below the contact glass, and light is emitted from a plurality of sensors through the contact glass surface. The size of the document is determined based on the presence or absence of reflected light from the document surface.

  This document reading apparatus includes a rotatable opening / closing section having a document presser that presses a document on the contact glass against the contact glass, the back surface of the document presser is white, and the outside of the document area is black. It is prevented from being read. Therefore, when the open / close part is completely closed and the original is pressed by the original presser (closed position), the original size can be accurately detected by the original size detection sensor. However, the original presser is not closed and the original is pressed. When is pressed (open position), all the sensors of the document size detection sensor react and cannot accurately detect the size of the document.

  Therefore, a technique is disclosed in which the document size detection timing is set to be performed when the document is placed at a predetermined position on the contact glass and the document presser is closed to an angle as close to the closed position as possible (for example, Patent Documents). 1). According to this, the apparatus main body provided with the contact glass on which the document to be read is placed, the reading means disposed below the contact glass and reading the document on the contact glass, and the document on the contact glass disposed below the contact glass. A document size detection sensor for detecting the size of the document, an opening / closing portion provided so as to be rotatable with respect to the apparatus main body and pressing the document on the contact glass against the contact glass, and the opening / closing portion from the open position An opening / closing angle detection means for detecting that the glass is closed to a predetermined angle at which the document size should be detected is provided, and this opening / closing angle detection means is installed on one of the apparatus body and the opening / closing section. A sensor, and a shutter attached to the other for operating the opening / closing angle detection sensor.

  In FIG. 9, the document reading apparatus includes a light shielding plate 12 attached to the opening / closing portion 4 outside the document placement area of the contact glass 2, in addition to the document size detection sensor 8, and the apparatus main body provided with the contact glass 2. 1 is provided with an opening / closing angle detection sensor 3 that is operated by the light shielding plate 6. When the document 7 is set at a predetermined position on the contact glass 2 and the opening / closing portion 4 is closed, the opening / closing portion 4 The light shielding plate 6 and the opening / closing angle detection that a predetermined document size detection position, that is, a position slightly ahead of the position b that interferes with the document size detection by the document size detection sensor 8 in the apparatus body 1 (that is, the a side) is reached. The detection by the sensor 3 is performed, and the document size detection is determined by the output signal from the document size detection sensor 8 at that time.

  According to this document reading apparatus, a sensor operated by a shutter is used as an opening / closing angle detection means for detecting that the opening / closing part is closed to a predetermined angle with respect to the contact glass. By installing a shutter on one side and a sensor on the other side, there is no need to provide a separate sensor outside the contact glass document placement area, and the area of the contact glass can be reduced, thus reducing the size of the device. Further, since this sensor is only operated by a shutter, it has an effect of preventing malfunction.

On the other hand, in the case of a thick document such as a book, as shown in FIG. 10, the opening / closing portion 4 is inserted into the apparatus body 1 using a hinge 4 and a thick document 7 such as a book is placed on the contact glass 2. When the opening / closing portion 4 is closed and the back surface (document retainer) 5 of the opening / closing portion 4 comes into contact with the thick document 7, the insertion of the hinge 9 is lifted and the opening / closing portion 4 itself is lifted, and the document is evenly placed on the contact glass 2. A technique capable of pressing down is disclosed (for example, Patent Document 2).
In addition, when using thick documents, if the opening / closing part is closed and the back of the opening / closing part comes into contact with a thick document, the hinge will be bent and the opening / closing part will be lifted up so that the thick document is evenly placed on the contact glass. A technique capable of pressing down is also disclosed (for example, Patent Document 3).
Japanese Patent Laid-Open No. 10-145546 Japanese Patent No. 3202814 JP 9-96877 A

  However, in the case of the conventional method, as in Patent Document 3, when the hinge of the opening and closing part of the document presser is inserted into the apparatus main body, if a thick document such as a book is used, the document presser is closed and the lower surface of the document presser is a thick document. When the contact is made, the insertion of the hinge comes out and the document presser itself is lifted, so that the document can be uniformly pressed against the contact glass.

  Similarly, when using a thick document such as a book in the hinge of Patent Document 2, when the document presser is closed and the lower surface of the document presser is in contact with the thick document, the hinge is bent and the document presser itself is lifted to contact the document. It is possible to press the document evenly against the glass. Here, when the sheet original is used and when the thick original is used, the output signal of the open / close angle detection sensor is as shown in the column of the sheet original prior art in Table 1 below.

  First, in the case of the sheet document 7 of FIG. 9, the opening / closing angle detection sensor 8 at the position a where the document retainer 4 is opened is closed from OFF as shown in Table 1, and the light shielding plate 6 reaches the opening / closing angle detection sensor 8 at the position b. After the opening / closing angle detection sensor 6 is switched from OFF to ON as shown in Table 1 and the document size is determined, the document retainer 4 is further closed, and the lower surface 5 of the document retainer 4 comes into contact with the sheet document 7 so that a copy is possible. .

  However, when the thick original 7 of FIG. 10 is used, the opening / closing angle detection sensor 8 at the position c where the original retainer 4 is opened is closed from OFF as in the column of the prior art of the thick original 7 in Table 1. At the position d where the light-shielding plate 6 reaches the opening / closing angle detection sensor 8, the opening / closing angle detection sensor 8 praises from OFF to ON as shown in Table 1, and after confirming the document size, the document presser 4 is further closed to close the document presser. 4, the lower surface 5 of the document 4 comes into contact with the thick original document 7, and in the case of Patent Document 3, when the document retainer 4 itself is lifted as in the position “e” in FIG. 10, the light shielding plate 6 of the document retainer 4 is also lifted simultaneously. It can be seen from Table 1 that the plate 6 is removed from the opening / closing angle detection sensor 8 and switched from ON to OFF, and the apparatus itself is again in the same OFF signal state as when the document presser 4 is opened.

When the copy start button is pressed in this state, the copying machine body 1 misunderstands that the document retainer 4 is open, and the document size detection sensor 8 looks at the signal when the copy button is pressed. However, since the actual document presser 4 itself is in a state in which the lower surface 5 of the document retainer 4 is in contact with the thick original document 7 and is lifted, the apparatus itself reads the white color of the lower surface 5 of the document retainer 4 and erroneously detects the document size. There was a problem.
SUMMARY OF THE INVENTION An object of the present invention is to provide a document reading apparatus and an image forming apparatus that accurately detect a document size.

According to the first aspect of the present invention, there is provided an apparatus main body provided with a contact glass on which an original is placed on the upper surface, an open / close section provided on the upper surface of the apparatus main body so as to be able to open and close, and an open / closed state of the open / close section detected An opening / closing angle detecting means for detecting the size of the document according to the opening / closing state of the opening / closing unit, and after the document size detection sensor detects the document size, In the document reading apparatus including the reading unit for reading the document, the opening / closing portion is provided so that the upper surface of the thick document can be pressed by being lifted up when the thick document is placed on the contact glass. The opening / closing angle detecting means includes a detection groove and a light shielding plate that shields light by moving the detection groove following the opening / closing portion. Be one that detects the opening and closing status by the presence or absence of, when a state of closing the opening portion by placing a document with a thickness of the contact glass, the side edge of the document the closing part with the thickness and equivalent The light shielding plate shields the opening / closing angle detecting means until it comes into contact, and the opening / closing part is not shielded by separating the light shielding plate from the detection groove as the whole of the opening / closing part is lifted. The thick original is pressed over the entire surface, the opening / closing angle detection means is detected to be in the closed state, and the original size detection sensor is operated.

  According to the first aspect of the present invention, when a thick original is placed on the contact glass and the opening / closing part is closed, the opening / closing part holds the thick original over the entire surface and the opening / closing angle detecting means is closed. Is detected and the document size detection sensor is operated, so that the document size is accurately detected even for a thick document.

Further, the open / close angle detection means includes a detection groove and a light shielding plate that moves following the detection groove along the opening / closing portion. When reading a thick document, the light shielding plate is separated from the detection groove. When the movement is accurately detected and a thick original is read, the light shielding plate is separated from the detection groove, and the open / close angle detection means is reliably closed.

According to the second aspect of the present invention, there is provided an apparatus main body provided with a contact glass on which an original is placed on an upper surface, an opening / closing part provided on the upper surface of the apparatus main body so as to be able to open and close, and an opening / closing state of the opening / closing part. An opening / closing angle detection means for detecting, an original size detection sensor that is provided in the apparatus main body and detects the size of the original in accordance with an open / close state of the opening / closing portion, and after the original size detection sensor detects the original size In the document reading apparatus including the reading unit for reading the document, the opening / closing unit is capable of pressing the upper surface of the thick document by lifting the whole when the thick document is placed on the contact glass. The open / close angle detection means includes a push switch and a push member, and the push member pushes the push switch to energize the push switch. Therefore, the open / close state is detected, and when the thick original is placed on the contact glass and the open / close portion is closed, the open / close portion is in contact with the side edge of the thick original. The push member pushes the push switch to energize, and the push member moves away from the push switch as the whole of the open / close portion is lifted, so that the open / close portion removes the thick original. The presser is pressed over the entire surface, and it is detected that the opening / closing angle detection means is in the closed state, and the document size detection sensor is operated .

According to the invention of claim 2 , the open / close angle detection means includes a push switch and a push member, and when the push member pushes the push switch and energizes, it is detected that the open / close portion is open, and a thick original is read. At this time, since the push member is separated from the push switch, when the thick original is read, the push member is separated from the push switch, and the open / close angle detection means is reliably closed.

In order to solve the above problem , the opening / closing part may be a pressure plate .

By doing so, since the opening / closing part is a pressure plate, a thick original can be easily pressed against the contact glass, and the original can be read reliably.

In order to solve the above problem , the opening / closing unit may be provided with an automatic document feeder .

In this way, since the automatic document feeder is provided in the opening / closing section, a plurality of standard documents can be read continuously.

  According to the first aspect of the present invention, when the thick original is placed on the contact glass and the opening / closing part is closed, the opening / closing part holds the thick original over the entire surface, and the opening / closing angle detecting means is closed. Since the document size detection sensor is activated and the document size detection sensor is activated, the timing for determining the document size does not change depending on the thickness of the document. It is possible to provide a document reading apparatus that can accurately detect a document size even if it is a thick document without erroneous detection.

Further , the open / close angle detection means includes a detection groove and a light shielding plate that moves following the detection groove along the opening / closing portion, and when reading a thick document, the light shielding plate is separated from the detection groove. When the rotation is accurately detected and a thick original is read, the shading plate is separated from the detection groove, and the open / close angle detection means is securely closed, so that the original size can be accurately detected. .

According to the second aspect of the present invention, the open / close angle detection means includes the push switch and the push member, and the push member detects that the open / close portion is opened by energizing the push switch by pushing the push switch. When reading a document, the push member is separated from the push switch, so when reading a thick document, the push member is separated from the push switch, and the open / close angle detection means is securely closed, and the document size is set. It can be detected accurately. In addition, the opening / closing angle detection means can be configured at low cost.

  A document reading apparatus as an example of the present invention is applied to a scanner (image reading apparatus) of a copying machine as shown in FIG. 11 is an apparatus main body of the copying machine, 12 is a contact glass provided on the upper surface of the apparatus main body 11, 13 is an operation unit, 13a is a copy start key, and 14 is openable and closable so as to cover the contact glass 12 on the upper surface of the apparatus main body 11. An opening / closing portion provided on the back surface 15 is provided with a white sheet for pressing the document on the back surface 15 thereof.

  Reference numeral 16 denotes a hinge for supporting the opening / closing portion 14 so as to be rotatable with respect to the apparatus main body 11. Reference numeral 17 denotes a document placed on the contact glass 12. Reference numeral 18 denotes a lower part of the contact glass 12. This is a document size detection sensor for detecting the size of the placed document 17. The document size detection sensor 18 irradiates light toward the contact glass 12 and determines the size of the document based on the presence or absence of reflected light from the document surface. A plurality of document size detection sensors 18 are arranged so as to correspond to various document sizes. Yes.

  Specifically, as shown in FIG. 2A, reading means for reading the document 17 on the contact glass 12 is provided in the apparatus main body 1 below the contact glass 12, and the size of the document 17 on the contact glass 12 is set. Are detected, and the detected data is collated with the document size matrix of FIG. 2B to determine the document size.

  Returning again to FIG. 1, the opening / closing part 14 that is provided so as to be rotatable with respect to the apparatus main body 11 and presses the document 17 on the contact glass 12 against the contact glass 12 and the opening / closing part 14 from the open position to the contact glass 12. An open / close angle detection sensor (open / close angle detection means) 20 for detecting whether or not the document size is closed to a predetermined angle (open / close status), and the open / close angle detection sensor 20 is provided with a detection groove. A photo interrupter and a light shielding plate 22 that moves following the opening / closing part 14 are provided and attached to the apparatus main body 1.

  FIG. 3 shows a control block diagram of the reading apparatus of this example. When the document 17 is placed on the contact glass 12 and the opening / closing part 14 is closed to a predetermined angle, the light shielding plate 22 operates the opening / closing angle detection sensor 20 to close to the predetermined angle at which the document size should be detected. Output to the reading control as an output signal. The reading controller 31 detects the document size from the document size matrix shown in FIG. 2B in response to a signal from the document size detection sensor 18 to determine the document size and make a copy ready state. Then, the image reading sensor 32 and the scanner motor 33 are operated to read the image.

  When copying with the open / close unit 14 open, a signal that the copy start key is pressed from the operation unit 13 is sent from the main body control unit 34 to the reading controller 31 via the main body image processing unit 35. Then, it detects that the signal from the open / close angle detection sensor 20 is in an open state, detects the document size from the document size matrix of FIG. 2B based on the signal from the document size detection sensor 18, The document size is fixed and the document is ready for reading.

  In order to read a sheet document by the document reading apparatus configured as described above, the sheet document 17 is placed at a predetermined position on the contact glass 12 of the apparatus body 11. When the opening / closing unit 14 is closed as indicated by an arrow, the document size detection sensor 18 that detects the size of the sheet document when the opening / closing unit 14 is closed to a certain angle, and a predetermined angle at which document size detection is to be performed. The opening / closing angle detection sensor 20 that detects that the sheet has been closed and the light shielding plate 22 that operates the opening / closing angle detection sensor 20 determine the exact size of the sheet document, and read the sheet document 17 in accordance with the control of FIG. Is done.

  In this example, the attachment position of the opening / closing angle detection sensor 20 and the shape and attachment position of the light shielding plate 22 are light shielding when the opening / closing part 14 is in the open state as shown in the open position A as shown in FIGS. When the side edge 22a of the plate 22 is at the open position A1 away from the operating point P of the opening / closing angle detection sensor 20, and the opening / closing portion 14 is gradually closed to reach the document size detection angle, the side edge of the light shielding plate 22 is reached. When the position 22a becomes the position B1 where the operating point P of the opening / closing angle detection sensor 20 is blocked, and the opening / closing portion 14 is further closed and the opening / closing portion 14 is in the closed position pressing the sheet document 17 as shown in the closed position C, the light shielding plate 22 is reached. The side edge 22a of the opening / closing angle detection sensor 20 is in a closed position C1 that passes the operating point P, and the light shielding plate 22 is provided so as to be kept in the state of passing the operating point P.

  In this way, the output signal of the opening / closing angle detection sensor 20 is switched when the side edge 22a of the light shielding plate 22 reaches the position B1 while the opening / closing part 14 is changed from the open position to the closed position. Specifically, in the case of the sheet document 17, the light shielding plate 22 and the opening / closing angle detection sensor 20 serving as the opening / closing angle detection means are configured such that the opening / closing portion 14 is in the open position A1 and the light shielding plate 22 shields the opening / closing angle detection sensor 20. The open / close angle detection sensor 20 outputs an ON signal. In this example, 0N is set when light is shielded.

  When the opening / closing unit 14 is closed from this state, the shape of the light shielding plate 22 is set so that the light shielding plate 22 does not shield the opening / closing angle detection sensor 20 before reaching the distance that the document size detection sensor 18 can detect. Therefore, the opening / closing angle detection sensor 20 is switched from an ON → OFF signal (position B), and is output to the reading controller 31, and the document size is determined by the signal from the document size detection sensor 18 and becomes readable.

  Next, in order to read a thick original such as a book by the original reading apparatus of this example, as shown in FIG. 6, the opening / closing part 14 is closed in the direction of the arrow (E position), and the opening / closing part 14 Is brought into contact with the document 17, the document 17 is placed on the contact glass 12, and the fulcrum of the hinge 16 at the center of rotation of the opening / closing unit 14 is lifted from the apparatus body 1 from the D position. Accordingly, it is possible to evenly press the thick document 17 that is horizontal to the entire surface.

  By the way, when the document 17 is a thick material such as a book, the opening / closing part 14 is shielded from the opening / closing angle detection sensor 20 at the open position as indicated by the broken line D (D position). The sensor 20 outputs an ON signal. When the opening / closing portion 14 is closed from this position and reaches the position that can be detected by the document size detection sensor 18, the position of the opening / closing angle detection sensor 20 is switched from ON to OFF when the position of the broken line E is reached (E position). When the portion 14 is closed to the position F, it is detected that the opening / closing portion 14 is in contact with the original document 17 and the fulcrum of the hinge 16 at the center of rotation of the opening / closing portion 14 is lifted from the apparatus body 11. The back surface 15 of the opening / closing part 14 is horizontal to the contact glass 12.

  At the position of the broken line E when the opening / closing part 14 is closed and brought into contact with the document 17, the side end part 22a of the light shielding plate 22 has already moved away from D1 that blocks the operating point P, as shown in FIG. At the position E1, the hinge 16 is lifted from the apparatus main body 11 as indicated by a one-dot chain line from this state, and becomes the F position. At this time, since the side end portion 22a of the light shielding plate 22 is separated from the detection groove of the photo interrupter and is at a position F1 away from the operating point P, the opening / closing angle detection sensor 20 outputs a signal that is always OFF to the control device, There is no signal change due to this operation.

  This series of operations will be described with reference to the flowchart of FIG. First, in S1, the opening / closing angle detection sensor 20 is always checked to determine whether the opening / closing angle detection sensor 20 is OFF. In a state where the opening / closing part 14 is open (position A in FIG. 4, position D in FIG. 6), the sensor is ON, so it closes (positions B and C in FIG. 4, positions E and F in FIG. 6). ) And the sheet original 17 and the thick original 17, the output signal of the open / close angle detection sensor 20 is switched from ON to OFF. When the output signal is OFF, the process proceeds to S2, where the reading controller 31 detects and determines the document size from the document size matrix based on the signal from the document size detection sensor 18, and sets it to the readable state.

Next, in S3, it is determined whether or not the copy button 13a on the operation unit 3 has been pressed and waits until it is pressed. When the copy button 3a is pressed, a start signal of the copy start button 13a is output to the reading controller 31 through the operation unit 13, the main body control unit 34, and the image processing unit 35, and reading is started with a fixed document size.
In S4, the reading controller 31 scans the range of the document size determined by the scanner (not shown) by driving the motor. A document signal read by the image reading sensor 32 is output to the main body image processing unit 35 as image data, and the main body control unit 34 creates an image based on this image data, and transfers it onto a transfer sheet.

  In S1, when the opening / closing part 14 is closed (positions B and C in FIG. 4, positions E and F in FIG. 6), the opening / closing angle detection sensor 20 is ON. It is determined whether the copy button 13a of the section 13 has been pressed, and waits until it is pressed. When the copy button 13a is pressed, a copy start button start signal is output to the reading controller 31 via the operation unit 13, the body control unit 34, and the image processing unit 35 in S6, and a signal from the document size detection sensor 18 is output. To determine the document size detected in the document size matrix. In step S7, the reading controller 31 scans a range of document sizes determined by a scanner (not shown) by driving a motor. A document signal read by the image reading sensor 32 is output to the main body image processing unit 35 as image data, and the main body control unit 34 creates an image based on this image data, and transfers it onto a transfer sheet.

  As described above, in this example, since the opening / closing angle detection sensor 20 always outputs the same output signal to the reading controller 31 regardless of the thickness of the document, the size of the white sheet on the back surface 15 of the opening / closing unit 14 is detected. The sensor 18 is not erroneously detected and the original size is not erroneous.

In the document reading apparatus of this embodiment, the opening / closing part 14 is described as a pressure plate. However, even if the opening / closing part 14 is an automatic document feeder (ADF), the opening / closing part 14 is a frame of the automatic document feeder. The same effect can be obtained by configuring the light shielding plate 22 integrally or attached to the frame in the same manner. In this embodiment, the open / close angle detection means is configured by the photo interrupter and the light shielding plate 22 as the open / close angle detection sensor 20 having the detection groove. However, the open / close angle detection sensor 20 may be configured by a push switch and a push member. Good. In this case, when the push member pushes the push switch and is energized, it is detected that the opening / closing portion is open, and when the thick original is read, the push member is separated from the push switch.
Moreover, the opening / closing part 14 may be configured by a pressure plate.

  Further, in this example, the document reading device provided in the copying machine has been described. However, the present invention is not limited to this, and can be applied to any document reading device such as a multifunction device such as a facsimile / copier or a scanner. Can do.

1 is a perspective view of a main part of a copying machine provided with a document reading apparatus as an example of the present invention; (A) is a figure which shows the document size detection sensor with which the contact glass of FIG. 1 is equipped, (b) is a document size matrix. FIG. 2 is a control block diagram of FIG. 1. FIG. 2 is a schematic cross-sectional view when a sheet document is placed on the document reading device of FIG. 1. It is a principal part enlarged view of FIG. FIG. 2 is a schematic cross-sectional view when a thick original is placed on the original reading apparatus in FIG. 1. It is a principal part enlarged view of FIG. 2 is a processing flowchart of the document reading apparatus of the example of FIG. FIG. 10 is a schematic cross-sectional view when a sheet document is placed on a conventional document reading apparatus. It is a schematic sectional view when a thick original is placed on a conventional original reading apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Apparatus main body 12 Contact glass 13 Operation part 13a Start button 14 Opening / closing part 15 Back surface 16 Hinge 17 Original document 18, 18a, 18b Original document size detection sensor 20 Opening / closing angle detection sensor (opening / closing angle detection means)
22 Light-shielding plate 22a Side end 31 Reading controller 32 Image reading sensor (reading means)
33 Scanner motor 34 Main body control unit 35 Main body image processing unit

Claims (3)

An apparatus body with a contact glass on the top surface for placing an original;
An opening / closing part provided on the upper surface of the apparatus body so as to be openable and closable so as to cover the contact glass;
An opening / closing angle detecting means for detecting an opening / closing state of the opening / closing section;
A document size detection sensor that is provided in the apparatus main body and detects the size of the document according to the open / close state of the opening / closing unit;
A document reading apparatus comprising: a reading unit that reads the document after the document size detection sensor detects the document size;
The opening / closing part is provided so that the upper surface of the thick original can be pressed by lifting the whole when the thick original is placed on the contact glass,
The opening / closing angle detection means includes a detection groove and a light shielding plate that shields light by moving the detection groove following the opening / closing portion, and detects the opening / closing state based on the presence or absence of light shielding by the light shielding plate. There,
When the state of the document a thick closed the opening portion put on the contact glass, the light shielding plate shields the opening angle detection means to said closing portion comes into contact with the side edge of the document with the thickness As the entire opening / closing portion is lifted, the opening / closing portion holds the thick original so that the opening / closing portion does not shield the opening / closing angle detection means by separating the light-shielding plate from the detection groove. An original reading apparatus characterized by detecting that the means is in the closed state and operating the original size detection sensor. An apparatus body with a contact glass on the top surface for placing an original;
An opening / closing part provided on the upper surface of the apparatus body so as to be openable and closable so as to cover the contact glass;
An opening / closing angle detecting means for detecting an opening / closing state of the opening / closing section;
A document size detection sensor that is provided in the apparatus main body and detects the size of the document according to the open / close state of the opening / closing unit;
A document reading apparatus comprising: a reading unit that reads the document after the document size detection sensor detects the document size;
The opening / closing part is provided so that the upper surface of the thick original can be pressed by lifting the whole when the thick original is placed on the contact glass,
The open / close angle detection means includes a push switch and a push member, and the push member detects the open / close state by energizing the push switch by pushing the push switch.
When the thick original is placed on the contact glass and the opening / closing part is closed, the push member presses the push switch until the opening / closing part contacts the side edge of the thick original, As the whole of the opening / closing part is lifted, the push member is separated from the push switch to be in a non-energized state, so that the opening / closing part holds the thick document over the entire surface, and the opening / closing angle detecting means is closed. A document reading apparatus, wherein the document size detection sensor is activated and the document size detection sensor is operated. An image forming apparatus comprising the document reading device according to claim 1.

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