JP2017034382A - Original size detection device and image reading apparatus - Google Patents

Abstract

Means for suppressing power consumption by a document size detection sensor is provided. An original platen on which an original is placed, an original platen provided to be openable / closable with respect to the original platen, an open / close detecting unit for detecting opening / closing of the original platen, and an original placed on the original platen Document size detection means for detecting the size of the document, a storage unit for storing the detection result of the document size detection means, and power supply to the document size detection means when the opening / closing detection means detects the closing of the document pressure plate. And a control unit that stops power supply to the document size detection unit when the detection result of the document size detection unit is stored in the storage unit. [Selection] Figure 1

Description

  The present invention relates to a document size detection device and an image reading device that detect the size of a document to be read.

  The conventional document size detection device detects the opening angle of the document pressure plate that holds the document depending on the state of the optical sensor in two stages. When the first stage opening angle is detected, the document size detection sensor is turned on, and the first stage is turned on. When the second opening angle lower than the opening angle is detected, the size of the document is determined based on the output result of the document size detection sensor (see, for example, Patent Document 1).

JP 2004-258386 A

However, in the conventional technique, when the first-stage open angle state of the original pressure plate that holds down the original continues, the original size detection sensor is kept on and consumes unnecessary power. There is.
An object of the present invention is to solve such a problem, and an object of the present invention is to suppress power consumption by a document size detection sensor.

  Therefore, the present invention provides a document table on which a document is placed, a document pressure plate provided so as to be openable / closable with respect to the document table, an open / close detection means for detecting opening / closing of the document pressure plate, and a document table placed on the document table. An original size detecting means for detecting the size of the original document, a storage unit for storing the detection result of the original size detecting means, and when the closing of the original pressure plate is detected by the open / close detecting means, the original size detecting means And a controller that stops power supply to the document size detection unit when power supply is started and the detection result of the document size detection unit is stored in the storage unit.

  According to the present invention as described above, it is possible to suppress the power consumption by the document size detection sensor.

The block diagram which shows the control structure of the original size detection apparatus in an Example Schematic side sectional view showing the configuration of the image reading apparatus in the embodiment Schematic plan view showing the configuration of the image reading apparatus in the embodiment Flowchart showing the flow of document size detection processing in the embodiment Time chart of power control of document size detection sensor in embodiment Explanatory drawing of document size determination in the embodiment Explanatory drawing of the document size determination table in the embodiment Explanatory drawing of A4R document size determination in the embodiment

  Embodiments of a document size detection apparatus and an image reading apparatus according to the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic sectional side view showing the configuration of the image reading apparatus in the embodiment. FIG. 3 is a schematic plan view showing the configuration of the image reading apparatus in the embodiment. FIG. 3 is a plan view of the document table on which the document is placed as viewed from above.
2 and 3, the image reading apparatus 100 includes a document size detection device that detects the size (size) of a document to be read, and is, for example, a scanner device having an image reading function. The image reading apparatus 100 includes a document table 102, an image reading sensor 103, a document pressure plate 104, sensor flags 105 and 113, open / close sensors 106 and 112, a casing 107, a document table size label 108, and document alignment. A mark 109 and document size detection sensors 110 and 111 are provided.

The document table 102 is made of transparent glass on which a document 101 as an image reading target is placed. In this embodiment, it is assumed that the document table 102 has a size that allows the A3 size document 101 to be placed as the maximum size document 101.
The image reading sensor 103 irradiates the original 101 placed on the original table 102 with light, reads the reflected light with a CCD (Charge Coupled Device) sensor or the like, and generates image data. The image reading sensor 103 is configured to be movable in the sub-scanning direction, and reads a document while moving in the sub-scanning direction.

  The document pressure plate 104 is provided so as to be openable and closable with respect to the document table 102, and presses the document 101 placed on the document table 102 against the document placement surface of the document table 102. The document pressure plate 104 is rotatably provided with a rotation shaft 104a provided on the back side of the image reading apparatus 100 as a rotation fulcrum, and the front side of the image reading apparatus 100 operated by a user is a free end.

  Therefore, the document 101 is placed on the document table 102 by rotating the front side of the image reading apparatus 100 of the document pressure plate 104 upward by the user's operation to open the document placement surface of the document table 102. Be able to. When the document 101 placed on the document table 102 is read by the image reading sensor 103, the document pressure plate 104 is moved downward on the front side of the image reading device 100 in order to press the document 101 against the document table 102 and prevent disturbance light from entering. And the document placement surface of the document table 102 is closed.

  The sensor flag 105 is slidably disposed on the back side of the image reading apparatus 100 on the rotation shaft 104a side, which is a rotation fulcrum of the document pressure plate 104, and moves in contact with the rotating document pressure plate 104. The sensor flag 105 is urged toward the document pressure plate 104 by an urging means such as a spring. Therefore, when the front side of the image reading apparatus 100 of the original pressure plate 104 is rotated downward, the sensor flag 105 is pushed and moved in the direction indicated by the arrow A in the drawing by the original pressure plate 104 that contacts the original pressure plate 104. When the front side of the image reading apparatus 100 is rotated upward, the urging means moves in the direction indicated by the arrow B in the figure.

  The sensor flag 113 is slidably disposed on the front side of the image reading apparatus 100 opposite to the rotation shaft 104a which is the rotation fulcrum of the document pressure plate 104, and moves in contact with the rotating document pressure plate 104. . The sensor flag 113 is urged toward the document pressure plate 104 by an urging means such as a spring. Accordingly, when the front side of the image reading apparatus 100 of the document pressure plate 104 is rotated downward, the sensor flag 113 is pushed in and moved in the direction indicated by the arrow A in the drawing by the document pressure plate 104 that is in contact with the sensor flag 113. When the front side of the image reading apparatus 100 is rotated upward, the urging means moves in the direction indicated by the arrow B in the figure.

An open / close sensor 106 serving as first open / close detection means detects an open state and a closed state of the document pressure plate 104. The open / close sensor 106 is composed of an optical sensor or the like, and detects a moving sensor flag 105 to detect an open state and a closed state of the document pressure plate 104.
The open / close sensor 112 as the second open / close detection means detects an open state and a closed state of the document pressure plate 104. The open / close sensor 112 is configured by an optical sensor or the like, and detects a moving sensor flag 113 to detect whether or not the document pressure plate 104 is in a closed state in contact with the document table 102.

  The document table size label 108 is provided on the outer periphery of the document table 102, and indicates the document size (B6, A5, B5, A4, B5R, A4R, B4R, A3, etc.) are entered. B6, A5, B5, and A4 are notations when the originals of the respective sizes are placed on the document table 102 with the longitudinal direction as the main scanning direction and the short direction as the sub-scanning direction, and B5R, A4R, B4R is a notation when a document of each size B5, A4, and B4 is placed on the document table 102 with the longitudinal direction as the sub-scanning direction and the short direction as the main scanning direction. A3 is a notation when the document is placed on the document table 102 with the longitudinal direction of the document as the sub-scanning direction and the short direction as the main scanning direction.

  The document alignment mark 109 is used to align one vertex of the document placed on the document table 102. It is assumed that the user places the document 101 on the document table 102 with one vertex of the document 101 aligned with the document alignment mark 109. In FIG. 3, the area represented by the broken lines on the two sides corresponds to the size (B6, A5, B5, A4, B5R, A4R, B4R) of the document placed on the document table 102 in accordance with the document alignment mark 109. It represents the corresponding area.

  A document size detection sensor 110 and a document size detection sensor 111 serving as document size detection means are sensors that detect the size (size) of the document 101 placed on the document table 102 with one vertex aligned with the document alignment mark 109. is there. The document size detection sensor 110 and the document size detection sensor 111 are, for example, reflective optical sensors. The document 101 is irradiated with light emitted from a light emitting element, and the reflected light is received by a light receiving element. Detects.

  As shown in FIG. 3, the document size detection sensor 110 is disposed outside the A4 document size region and inside the B5R document size region, which is indicated by a broken line in the sub-scanning direction. The document size detection sensor 110 is configured to check whether a B6, A5, B5, and A4 size document 101 is placed on the document table 102 with the long side as the main scanning direction and the short side as the sub scanning direction. , It is detected whether the A3 size document 101 is placed on the document table 102 with the long side direction as the sub-scanning direction and the short side direction as the main scanning direction.

  As shown in FIG. 3, the document size detection sensor 111 is disposed outside the A4R document size region and inside the B4R document size region indicated by the broken line. The document size detection sensor 111 is used to detect the letter size document 101 and the legal size document 101.

In this embodiment, the distance between the document size detection sensor 111 and the document alignment mark 109 is larger than the distance between the document size detection sensor 110 and the document alignment mark 109 in the main scanning direction.
The housing 107 covers the image reading sensor 103, the open / close sensors 106 and 112, the document size detection sensors 110 and 111, and the like.

FIG. 1 is a block diagram illustrating a control configuration of the document size detection apparatus according to the embodiment.
In FIG. 1, a document size detection device 120 includes an image reading sensor 103, open / close sensors 106 and 112, document size detection sensors 110 and 111, a sensor value storage unit 114, a document size detection control unit 115, and a sensor power source. And a supply unit 116.
The document size detection device 120 is provided in the image reading device 100 shown in FIGS. The description of the image reading sensor 103, the open / close sensors 106 and 112, and the document size detection sensors 110 and 111 has been described above, and will be omitted.

The sensor power supply unit 116 supplies power to the document size detection sensor 110 and the document size detection sensor 111.
The sensor value storage unit 114 as a storage unit is a memory or the like that stores the output results of the document size detection sensor 110 and the document size detection sensor 111 as numerical values.
The document size detection control unit 115 as a control unit controls the image reading sensor 103, the sensor power supply unit 116, and the sensor value storage unit 114, and the document 101 placed on the document table 102 shown in FIGS. The control which detects the size of is performed.

In this embodiment, when the document size detection control unit 115 detects that the document pressure plate 104 shown in FIG. 2 is closed by the open / close sensor 106, the sensor power supply unit 116 starts supplying power to the document size detection sensors 110 and 111. When the detection results of the size detection sensors 110 and 111 are stored in the sensor value storage unit 114, the power supply to the document size detection sensors 110 and 111 is stopped by the sensor power supply unit 116.
The document size detection control unit 115 includes a control unit such as a CPU (Central Processing Unit) and a storage unit such as a memory, and the entire document size detection device 120 is based on a control program (software) stored in the storage unit. To control the operation.

The operation of the above configuration will be described.
First, document size detection processing performed by the document size detection device will be described with reference to FIGS. 1, 2 and 3 in accordance with a step S in the flowchart showing the flow of document size detection processing in the embodiment of FIG. .
The document size detection control unit 115 of the document size detection device 120 starts document size detection processing when the power is turned on.

S1: The document size detection control unit 115 monitors the state of the open / close sensor 106, and when detecting that the document pressure plate 104 is opened, the process proceeds to S2.
The document size detection control unit 115 uses the open / close sensor 106 to detect that the document pressure plate 104 has been opened by a user operation. It is assumed that the user places the document pressure plate 104 in the open state and places one apex of the document on the document table 102 with the document alignment mark 109.

S2: The document size detection control unit 115 monitors the state of the open / close sensor 106, waits until the document pressure plate 104 is closed, and moves to S3 when detecting that the document pressure plate 104 is closed. .
It is assumed that the user who placed the document on the document table 102 closes the document pressure plate 104.
S3: When the document size detection control unit 115 detects that the document pressure plate 104 is closed, the document size detection control unit 115 instructs the sensor power supply unit 116 to start supplying sensor power to the document size detection sensor 110 and the document size detection sensor 111. . The sensor power supply unit 116 starts power supply to the document size detection sensor 110 and the document size detection sensor 111 in accordance with an instruction from the document size detection control unit 115.

S4: The document size detection control unit 115 stands by until a predetermined time elapses until the document size detection sensor 110 and the document size detection sensor 111 to which power is supplied start up (until activation).
S5: When the document size detection control unit 115 detects that a predetermined time has elapsed, it instructs the sensor value storage unit 114 to store the output values of the document size detection sensor 110 and the document size detection sensor 111. The sensor value storage unit 114 stores output values from the document size detection sensor 110 and the document size detection sensor 111 in accordance with an instruction from the document size detection control unit 115.

  S6: When the sensor value storage unit 114 stores the output values from the document size detection sensor 110 and the document size detection sensor 111, the sensor value storage unit 114 notifies the document size detection control unit 115 of a signal indicating completion of storage of the sensor output value. Upon receipt of a storage completion signal from the sensor value storage unit 114, the document size detection control unit 115 instructs the sensor power supply unit 116 to stop supplying sensor power to the document size detection sensor 110 and the document size detection sensor 111.

S7: The document size detection control unit 115 monitors the state of the open / close sensor 112. If the document pressure plate 104 is further closed by the user's operation and the document pressure plate 104 is closed, the process proceeds to S9. On the other hand, in the open state, the process proceeds to S8.
S8: When the document pressure plate 104 is open, the document size detection control unit 115 checks the state of the open / close sensor 106. When the document pressure plate 104 is closed, the process proceeds to S7, and the document pressure plate 104 is open. In this case, the process proceeds to S2.

S9: When the opening / closing sensor 112 detects that the document pressure plate 104 is closed, the document size detection control unit 115 operates the image reading sensor 103 to detect the document size in the main scanning direction in FIG. Scan direction document size detection processing is performed.
S10: When the document size detection control unit 115 completes the main scanning direction document size detection processing, the output values from the document size detection sensor 110 and the document size detection sensor 111 stored in the sensor value storage unit 114, and the image reading sensor. A document size determination process is performed to determine the size of the document 101 placed on the document table 102 based on the document size in the main scanning direction detected by the process 103, and the process ends. Details of the document size determination process will be described later.

Next, the switching position of the open / close state of the open / close sensor 106 will be described with reference to FIGS. 1 and 2. The position at which the open / close sensor 106 detects the closed state of the document pressure plate 104 is a time during which the sensor value storage unit 114 can store the output values from the document size detection sensor 110 and the document size detection sensor 111 under the control of the document size detection control unit 115. Must be set to ensure.
In this embodiment, the open / close sensor 106 closes the document pressure plate 104 when the distance between the document table 102 and the document pressure plate 104 at a position where the document size detection sensor 110 is disposed is equal to or less than a predetermined distance (D3). I try to detect it.

Hereinafter, a position where the open / close sensor 106 detects the closed state of the document pressure plate 104 will be described.
In FIG. 2, the distance D <b> 1 is the distance between the document platen 102 and the document pressure plate 104 that can detect the presence or absence of the document 101 placed on the document table 102 by the document size detection sensor 110 above the document size detection sensor 110. The shortest distance.

  The document size detection sensor 110 and the document size detection sensor 111 irradiate the document with light emitted from the light emitting element, and detect the reflected light by the light receiving element to detect the presence or absence of the document. Therefore, when the distance between the document platen 102 and the document pressure plate 104 becomes smaller than D1 above the document size detection sensor 110, the presence or absence of the document cannot be correctly detected by the reflected light of the light irradiated on the document pressure plate 104. End up.

  Therefore, the output value of the document size detection sensor 110 when the distance between the document table 102 and the document pressure plate 104 is D1 or more must be used above the document size detection sensor 110. The distance D1 is determined by the specifications of the light emitting element and the light receiving element of the document size detection sensor 110. In this embodiment, the distance D1 is 60 mm.

The distance D2 is determined by the sensor value storage unit 114 after the open / close sensor 106 detects the closed state of the document pressure plate 104 and power supply to the document size detection sensor 110 and the document size detection sensor 111 is started. This is the distance that the document pressure plate 104 can be moved by the user's operation above the document size detection sensor 110 during the time until the output value of the document size detection sensor 111 is stored.
Here, the open / closed state of the open / close sensor 106 and the time from when power is supplied to the document size detection sensors 110 and 111 to start-up will be described based on the time chart shown in FIG. 5 with reference to FIG.

  In FIG. 5, T1 indicates that the document size detection control unit 115 instructs the sensor power supply unit 116 to start power supply to the document size detection sensor 110 and the document size detection sensor 111 after the open / close sensor 106 is opened. This is the firmware processing time until the document size detection sensor 110 and the document size detection sensor 111 are turned on (turned on). In this embodiment, the time T1 is 10 ms.

  T2 is the activation time of the document size detection sensor 110 and the document size detection sensor 111. This time T2 is determined by the specifications of the document size detection sensor 110 and the document size detection sensor 111, but is generally about 1 ms. In this embodiment, the time T2 is 1 ms.

  In T3, after the time T2 has elapsed, the document size detection control unit 115 instructs the sensor value storage unit 114 to store the output values of the document size detection sensor 110 and the document size detection sensor 111, and the document size detection sensor 110 and the document This is the firmware processing time until the output value of the size detection sensor 111 is stored in the sensor value storage unit 114. In this embodiment, the time T3 is 10 ms.

Time T4 is the total time of time T1, time T2, and time T3. In the present embodiment, time T4 = 10 ms + 1 ms + 10 ms = 21 ms.
On the other hand, it has been found from experimental results that the speed at which the user closes the document pressure plate 104 is 0.66 m / s at the maximum above the document size detection sensor 110. Therefore, the distance that the original platen 104 moves at time T4 = 21 ms is 13.86 mm.

Returning to the description of FIG. 2, since the distance that the original pressure plate 104 moves at time T4 = 21 ms is 13.86 mm, in this embodiment, the distance D2 is 15 mm. Further, since the distance D3 is the distance D1 + the distance D2, the distance D3 is 75 mm in this embodiment.
The sensor flag 105 is configured so that the output of the open / close sensor 106 is closed when the distance between the document table 102 and the document pressure plate 104 is a distance D3 (= 75 mm) above the document size detection sensor 110. Has been.

  That is, a period from when the open / close sensor 106 detects the closed state of the document pressure plate 104 until the time T4 from when the output values of the document size detection sensor 110 and the document size detection sensor 111 are stored in the sensor value storage unit 114 elapses. In the meantime, when the speed at which the original pressure plate 104 advances toward the original table 102 above the original size detection sensor 110 is A (m / s = mm / ms), the distance D2 (mm) is the speed A (mm). / Ms) × time T4 (ms) or more.

Furthermore, when the total distance of the distance D1 determined by using the document size detection sensor 110 and the document size detection sensor 111 and the distance D2 is the distance D3, the open / close sensor 106 is located above the document size detection sensor 110. When the distance between the table 102 and the document pressure plate 104 becomes the distance D3, the document pressure plate 104 is configured to be switched between an open state and a closed state.
In addition, since the time T4 or more can be secured even above the document size detection sensor 111 whose distance from the rotation shaft 104a is larger than the document size detection sensor 110, the output of the document size detection sensor 111 can check whether or not there is a document. Can be detected.

That is, when a plurality of document size detection sensors are provided, the distance D3 is secured above the document size detection sensor having the shortest distance from the rotation shaft 104a, and the time T4 or more is secured, thereby detecting all document sizes. The presence or absence of a document can be detected by the output of the sensor.
Therefore, when the document size detection sensor 111 is arranged so that the distance from the rotation shaft 104a is smaller than the document size detection sensor 110, the document size detection sensor is secured by securing a time T4 or more above the document size detection sensor 111. The presence or absence of a document can be detected by the output of 110 and the document size detection sensor 111.

By configuring the opening / closing sensor 106 in this manner, the document size detecting sensor 110 and the document size are detected after the opening / closing sensor 106 detects the closed state of the document pressure plate 104 above the document size detecting sensor 110 and the document size detecting sensor 111. Since the time until the output value of the detection sensor 111 is stored in the sensor value storage unit 114 is T4 or more, the presence / absence of a document can be detected by the outputs of the document size detection sensor 110 and the document size detection sensor 111.
Next, document size determination processing performed by the document size detection control unit 115 will be described based on FIGS. 6 and 7 with reference to FIG. This document size determination process is a process performed in S10 of FIG.

First, the document size detection control unit 115 uses the image reading sensor 103 to determine whether or not the edge of the document placed on the document table 102 exists in the detection area 1, the detection area 2, and the detection area 3 in FIG. (Presence / absence) is determined, and a document size detection process in the main scanning direction for detecting the document size in the main scanning direction is performed. (Main scanning direction document size detection processing performed in S9 of FIG. 4)
Next, the document size detection control unit 115 detects the document size in the main scanning direction as a result of the document size detection processing in the main scanning direction, and the document size detection sensor 110 and the document size detection sensor 111 stored in the sensor value storage unit 114. Document size determination processing is performed based on the output value from.

The document size detection control unit 115 determines the document size by referring to the determination table 70 shown in FIG. 7 based on the document size in the main scanning direction and the output values from the document size detection sensor 110 and the document size detection sensor 111. To do.
A determination table 70 shown in FIG. 7 is a table composed of a document size detection processing result 71 in the main scanning direction, a document size detection sensor output value 72, and a document size 73 to be determined.
The main scanning direction document size detection processing result 71 is a result of the above-described main scanning direction document size detection processing, and is the presence or absence of document edges in the detection area 1, detection area 2, and detection area 3 shown in FIG.

The document size detection sensor output value 72 is an output value from the document size detection sensor 110 and the document size detection sensor 111 stored in the sensor value storage unit 114, and is detected by the document size detection sensor 110 and the document size detection sensor 111. The presence or absence of a manuscript.
The document size 73 to be determined is a document size corresponding to the document end presence / absence in the main scanning direction document size detection processing result 71 and the document size detection sensor output value 72 document presence / absence.
The document size detection control unit 115 determines the document size based on the document edge presence / absence in the main scanning direction document size detection processing result 71 and the document size detection sensor output value 72.

  For example, as shown in FIG. 8, when an A4 size document is placed on the document table 102 with the document alignment mark 109 so that the short side direction is the main scanning direction and the long side direction is the sub-scanning direction, As a result of the direction document size detection processing, the edge of the document is detected in the detection area 2, the document size detection sensor 110 detects the presence of a document, and the document size detection sensor 111 detects the absence of a document. Therefore, the document size is determined as “A4R”.

As described above, when the open / close sensor 106 detects that the original pressure plate 104 is closed by the original size detection device 120, the power of the original size detection sensors 110 and 111 is supplied, and the output values of the original size detection sensors 110 and 111 are stored. Then, by providing the document size detection control unit 115 for stopping the supply of power to the document size detection sensors 110 and 111, the power consumed by the document size detection sensors 110 and 111 can be minimized.
Further, the lifetime of the document size detection sensors 110 and 111 can be extended.

As described above, in this embodiment, when the open / close sensor detects that the document pressure plate is closed, the document size detection sensor is supplied with power and the output value of the document size detection sensor is stored. By providing the control unit for stopping the supply of the power, it is possible to minimize the power consumed by the document size detection sensor.
Further, it is possible to extend the life of the document size detection sensor.
In this embodiment, the image reading device is described as a scanner device. However, the image reading device is not limited thereto, and may be a copying machine, a facsimile machine, a multifunction peripheral (MFP), or the like as long as it has an image reading function.

DESCRIPTION OF SYMBOLS 100 Image reading apparatus 102 Document stand 103 Image reading sensor 104 Document pressure plate 105, 113 Sensor flag 106, 112 Open / close sensor 109 Document alignment mark 110, 111 Document size detection sensor 114 Sensor value storage unit 115 Document size detection control unit 116 Sensor power supply 120 Document size detection device

Claims (7)

An original table on which an original is placed;
An original platen provided to be openable and closable with respect to the original table;
Open / close detecting means for detecting opening / closing of the document pressure plate;
Document size detection means for detecting the size of the document placed on the document table;
A storage unit for storing a detection result of the document size detection unit;
When the open / close detection unit detects that the original platen is closed, the power supply to the original size detection unit is started. When the detection result of the original size detection unit is stored in the storage unit, the supply to the original size detection unit is stopped. A control unit,
A document size detection apparatus comprising: The document size detection device according to claim 1,
The open / close detection means detects the closing of the original pressure plate when the distance between the original platen and the original pressure plate at a position where the original size detection means is located reaches a predetermined distance. apparatus. The document size detection apparatus according to claim 2,
The predetermined distance is the shortest distance between the document table and the document pressure plate where the document size detection unit can detect the document placed on the document table, and power supply to the document size detection unit is started. The original size detecting device is characterized in that the original pressure plate is a total distance with a distance that can be moved by a user's operation from when the original size detection means stores the detection result to the storage unit. . In the document size detection apparatus according to claim 2 or 3,
When the document size detecting means is composed of a plurality of document size detecting means,
The open / close detecting means is configured to detect the original when the distance between the original platen and the original pressure plate becomes a predetermined distance at the position where the original size detecting means is disposed at the shortest distance from the rotation axis of the original pressure plate. An original size detecting device for detecting closing of a pressure plate. In the document size detection device according to any one of claims 1 to 4,
The control unit starts power supply to the document size detection unit, and stores the detection result of the document size detection unit in the storage unit after the document size detection unit is activated. apparatus. In the document size detection device according to any one of claims 1 to 5,
The control unit stops power supply to the document size detection unit after receiving notification from the storage unit that the detection result of the document size detection unit has been stored. .   An image reading apparatus comprising the document size detection apparatus according to claim 1.

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