JP5632439B2 - Document reader - Google Patents

Description

  Embodiments described herein relate generally to a document reading apparatus that automatically reads a document size in a digital copying machine or the like.

  Conventional automatic document size detection uses a method for determining the document size using a plurality of document size detection sensors and a reading mark on the back of the platen cover. A detection method was considered.

  However, when using a plurality of document size detection sensors, the cost of the sensor is high, and the reading accuracy with a reading mark on the back of the platen cover is deteriorated due to dirt or the like. was there.

JP 2006-67179 A

  The problem to be solved by the present invention is to provide a document reading apparatus capable of automatically detecting a document having a black background or a thick document without changing the hardware configuration.

The document reading apparatus according to the embodiment includes a document table on which a document is placed, and an output signal obtained by scanning the document on the document table in the main scanning direction. A line sensor that detects the size of the document, a first position that is open with respect to the document table, and a second position that is in the middle of closing from the first position can be opened and closed. is a platen cover for pressing the document placed on the platen, the platen cover the first position, the opening and closing position sensor for detecting that it is in the second position, a document reading apparatus having a A detection result of a first stage of the line sensor when the opening / closing position sensor detects that the platen cover is in the first position, and the opening / closing position sensor causes the platen cover to move to the second position. At the position When the detection result of the second stage of the line sensor is acquired, the detection result of the first stage is compared with the detection result of the second stage, and both detection results are inverted The first detection result is the size detection result, and when the detection results are not reversed , the difference between the first and second detection results is the size detection result.

1 is a diagram illustrating a schematic longitudinal section of a configuration example of a digital multi-function peripheral including a document reading device. It is a perspective view of an open / close position sensor. It is explanatory drawing of the relationship between the open / close position of a platen cover, and an open / close position sensor. It is a figure which shows schematic structure of the 1st and 2nd photo interrupter. It is a figure for demonstrating the opening-and-closing state of a platen cover, and the output of the 1st and 2nd photo interrupter. It is a figure which shows the schematic structure of a scanner. It is a top view of the state seen from the contact glass side from the contact glass side. It is an electrical equipment block diagram with which a digital copying machine is provided. It is a schematic diagram which shows the some reading location stored in a line memory in association with the position of contact glass or a document. It is a flowchart for demonstrating operation | movement. FIG. 11 is a flowchart illustrating a main part of a subroutine. FIG. 10 is a diagram for explaining a size detection result when a background of a normal document A4-R is white and black. FIG. 10 is a diagram for explaining a size detection result when the background of a document of a normal document A is white and black. FIG. 6 is a diagram for explaining a size detection result when a background of a normal document B is white and black. FIG. 6 is a diagram for explaining a size detection result when a background of a book document A4-R is white and black. FIG. 10 is a diagram for explaining a size detection result when a background of a book document A4 is white and black. FIG. 6 is a diagram for explaining a size detection result when a background of a book document B4 is white and black.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram illustrating a schematic longitudinal section of a configuration example of a digital multifunction peripheral including a document reading device.

  The digital copying machine 100 includes a scanner 10 that reads a document, and a printer 50 that forms an image based on image data output from the scanner 10 on a recording medium such as paper.

  A contact glass 11 on which a document is placed is provided on the upper surface of the main body case of the scanner 10. The document D is placed with the document surface facing the contact glass 11. A platen cover 12 for pressing the document D placed on the contact glass 11 is provided on the upper side of the contact glass 11 so as to be freely opened and closed.

  The surface of the platen cover 12 that holds the document D is white or a color close to white. An opening / closing position sensor 13 for detecting the opening / closing position of the platen cover 12 is provided. A white reference plate 14 for obtaining shading correction data and the like is provided at a predetermined position on the home position side of the contact glass 11.

  FIG. 2 is a perspective view showing the configuration of the open / close position sensor 13. The open / close position sensor 13 has a support shaft 131 attached in the body of the digital multi-function peripheral near the support shaft for opening and closing the platen cover 12. A rotating member 134 is rotatably supported on the support shaft 131. The rotating member 134 is supported in a state in which it is urged in the direction of a white arrow using, for example, a spring 137 and urged in a direction to open the platen cover 12. The rotating member 134 includes an integral movable part 132 and a shutter part 133. The shutter unit 133 includes a first shutter 133a and a second shutter 133b.

  The shutter unit 133 is arranged so that the first and second photo interrupters 135 and 136 can be controlled to be turned on / off by the first and second shutters 133a and 133b as the rotating member 134 rotates.

  Note that, instead of the first and second photo interrupters 135 and 136, photo-couplers that are similar photoelectric conversion means may be used. Moreover, a magnet may be provided at a position corresponding to the first and second shutters 133a and 133b, and the rotation state of the shutter unit 134 may be detected by detecting the magnet with a magnetic sensor. In short, it is only necessary to detect the positions of the first and second shutters 133a and 133b. The first and second photo interrupters 135 and 136 serve as first and second position sensors.

  The printer 50 includes a medium path 55 from a medium holding unit 51 that holds a recording medium P such as sheet-like paper, to the discharge unit 54 via an electrophotographic printer engine 52 and a fixing device 53.

  The printer engine 52 transfers the toner image formed on the surface of the photoreceptor 61 to the recording medium P by electrophotography using the charger 56, the exposure device 57, the developing device 58, the transfer device 59, the cleaner 60, and the like. Then, the transferred toner image is fixed on the recording medium P by the fixing device 53.

  In this embodiment, the printer engine 52 shows an example in which image formation is performed by an electrophotographic method. However, the present invention is not limited to this, and an inkjet method, a sublimation type thermal transfer method, a direct thermal recording method, etc. Various image forming methods may be used.

  FIG. 3 shows the relationship between the open / close position of the platen cover 12 and the open / close position sensor 13. FIG. 4 is a diagram illustrating a schematic configuration example of the first and second photo interrupters 135 and 136.

  When the platen cover 12 shown in FIG. 3A is in the open state (first position), each of the light receiving elements of the first and second photo interrupters 135 and 136 is in a state where it can receive light emitted from the light emitting element. is there. Therefore, the output of the first photointerrupter 135 shown in FIG. 4 is at L level, and the output of the second photointerrupter 136 is at L level.

  In the light receiving element of the first photo interrupter 135 in the state where the platen cover 12 shown in FIG. 3B is being closed (second position), light from the light emitting element is shut by the first shutter 133a. The output of the first photo interrupter 135 becomes H level. The output of the second photo interrupter 136 is in an L level state.

The output of the first photo interrupter 135 with the platen cover 12 shown in FIG. 3C closed is continuously at the H level. Light receiving element of the second photo-interrupter 136, light from the light emitting element in the second shutter 13 3b is shut. The output of the second photo interrupter 136 is at the H level.

  The outputs of the first and second photo interrupters 135 and 136 are supplied to the control unit 82 described later.

  FIG. 5 is a table showing the outputs of the first and second photointerrupters 135 and 136 when the platen cover 12 of FIGS. 3A to 3C is opened and closed.

  FIG. 6 is a diagram illustrating a schematic configuration of the scanner 10, and FIG. 7 is a top view illustrating a state in which the surface of the contact glass 11 is viewed from above.

  The scanner 10 is disposed below the contact glass 11. The scanner 10 includes an exposure scanning unit 104 including a light source 101 that emits light and a first carriage 102 on which a first mirror M1 is mounted, and a second carriage 103 on which second and third mirrors M2 and M3 are mounted. A line sensor 106 that reads an image on the document D by receiving reflected light from the document D guided by the three mirrors M1 to M3 through the imaging lens 105 is provided. As the line sensor 106, for example, a CCD image sensor is used.

  The line sensor 106 functions as an image sensor that acquires photoelectric conversion data (image data) obtained by photoelectric conversion of reflected light from the document D formed on the line sensor 106. The photoelectric conversion data is a voltage value having a magnitude corresponding to the intensity of reflected light from the document D. The first and second carriages 102 and 103 are provided so as to reciprocate along the contact glass 11 in the sub-scanning direction (left and right direction in FIG. 6). During the reading process of the document D placed on the contact glass 11, for example, in order to keep the optical path length constant by driving by a driving source such as a driving motor (not shown), for example, scanning traveling in the sub-scanning direction at a speed ratio of 2: 1. To do.

  A position sensor APS installed at a position facing the contact glass 11 detects the size of the document D in the sub-scanning direction. For example, an APS (Active-Pixel Sensor) is used as the position sensor APS.

  HP in FIG. 7 indicates a home position where a document is set. FIG. 7A shows the distance by which the first carriage 102 is moved to a predetermined position while being sub-scanned from the home position HP when the line sensor 106 detects the document size in the main scanning direction. The document size is detected at position A.

  FIG. 8 shows an electrical block diagram provided in the digital copying machine 100. Schematically, when the document D is set on the contact glass 11 of the scanner 10 and the start switch of the operation unit 84 is pressed, the scanner 10 reads the image of the document D. The read image data undergoes a series of image processing in the command processing unit 81, outputs the image data to the printer 50, and performs a recording operation on the recording medium P. Necessary parameters in the scanner 10, the instruction processing unit 81, and the printer 50 are held in a RAM 83 included in the control unit 82, and settings for each device are executed by the control unit 82. The controller 82 is connected to a ROM 90 that stores in advance a reference table for determining the document size based on the document size information read by the scanner 10.

  Further, mode information necessary for parameter setting can be designated by the user using the operation unit 84, and information is exchanged by communicating between the CPU 85 and the control unit 82 in the operation unit 84. Is configured to do. Reference numeral 86 denotes a touch panel display unit included in the operation unit 84, for example.

  The command processing unit 81 performs desired image processing on the image data of the document D received from the scanner 10. The command processing unit 81 includes a line memory 88 connected to the image processing module 87 in order to store image data when performing a document size detection operation. The instruction processing unit 81 also has a memory controller 89 that controls the line memory 88, and image data can be read / written from the control unit 82 to the line memory 88.

  FIG. 9 is a schematic diagram showing a plurality of reading locations stored in the line memory 106 in association with the positions of the contact glass 11 and the document D.

  PS1 to PS5 indicate detection positions where the line sensor 106 reads the size of the document D on the contact glass 11 in the main scanning direction. A circle indicated by hatching indicates a position sensor APS for reading the size of the document D in the sub-scanning direction. For example, based on the result of the line sensor 106 detecting the document size up to the detection position PS5 in the main scanning direction, a plurality of document sizes can be detected from the combination with the common position sensor APS in the sub-scanning direction.

  For example, when an A5 size document is placed horizontally (A5-R) on the contact glass 11, the line sensor 106 detects the detection position PS1 in the main scanning direction, and can determine that the document is A5 size. When a B5 size document is placed horizontally long (B5-R), the line sensor 106 detects the detection position PS2 in the main scanning direction, and can determine that the document is B5-R.

  When the line sensor 106 detects a document placed in the main scanning direction at the detection position PS3, the size of the placed document is determined to be A5 or A4-R. Similarly, the size of the document placed when the line sensor 106 detects the document at the detection position PS4 is determined to be B5 or B4. When the document on which the line sensor 106 is placed is detected at the detection position PS4, the size of the placed document is determined to be A4 or A3. Note that B4 and A3 sizes are not given -R because they are determined to be horizontally long from the size.

  The detection of the document size by the line sensor 106 is performed in two stages. In the detection with the platen cover 12 opened (first stage), the original portion becomes brighter than the platen cover 12 when the light source 101 is irradiated. On the other hand, when the light source 101 is irradiated during detection (second stage) when the platen cover 12 is being closed, the original portion of the platen cover 12 becomes darker than the first stage.

  By utilizing this characteristic, the document size detection is divided into two stages, and it is intended to prevent erroneous detection that there is a document outside the document when the size of a thick document such as a book document is detected in the second stage. is there.

  Information on the detection positions PS1 to PS5 detected by the line sensor 106 is supplied to the control unit 82 as an output of the scanner 10.

  Therefore, verification is performed between detection in the state in which the platen cover 12 is open (first stage) and detection in the state in which the platen cover 12 is being closed when reading a thick book original (second stage). The detection positions PS1 to PS5 are determined.

Hereinafter, detection of the document size will be described with reference to the flowchart of FIG. FIG. 10 explains the document size detection by the control unit 82 based on the detection results of the open / close position sensor 13, the line sensor 106, and the position sensor APS .

  Here, the platen cover 12 is opened, and the size detection operation is started assuming that the position of the first carriage 102 is in the size detection position shown in FIG.

  In ACT 1, the control unit 82 determines whether the copy start switch is turned on from the operation unit 84. When it is not turned on (No), the process proceeds to ACT2. When turned on (Yes), the process proceeds to ACT9.

  In ACT 2, the open / close position sensor 13 detects the first position of the platen cover 12.

  That is, when the platen cover 12 is closed by the user from a state in which the platen cover 12 is open, and the platen cover 12 moves to the first position (a position in the middle of closing), the open / close position sensor 13 detects it. . After this detection, the process proceeds to ACT3.

  In ACT3, the first-stage detection operation is executed.

  That is, when the open / close position sensor 13 detects the first position of the platen cover 12, the light source 101 is turned on to obtain output data from the line sensor 106 and store it in the RAM 83. After storing the output data, the light source 101 is turned off and the process proceeds to ACT4.

  In ACT4, it is determined whether or not the start switch of the operation unit 84 is turned on. When it is not turned on (No), the process proceeds to ACT5. When turned on (Yes), the process proceeds to ACT9.

  In ACT5, the open / close position sensor 13 detects whether or not the platen cover 12 has been opened.

  That is, it is detected whether the platen cover 12 is opened again and the platen cover 12 is opened again from the first position.

  If it is detected that the platen cover 12 is not opened again from the first position (No), that is, if the user does not open again and the platen cover 12 remains in the first position, the process proceeds to ACT6. To do.

  If it is not detected that the platen cover 12 is opened again from the first position (Yes), that is, if the user opens again and the platen cover 12 is opened again from the first position, the process returns to ACT1.

  In ACT 6, the open / close position sensor 13 detects the second position of the platen cover 12. When the user performs the closing operation of the platen cover 12 and the platen cover 12 moves from the first position to the second position (position in the middle of closing), the opening / closing position sensor 13 detects it. After this detection, the process proceeds to ACT7.

  In ACT7, the detection operation in the second stage is executed.

  That is, the light source 101 is turned on a predetermined time after the opening / closing position sensor 13 detects the second position of the platen cover 12, output data is obtained from the line sensor 106, and stored in the RAM 83. After storing the output data, the light source 101 is turned off and the process proceeds to ACT8. The term “after a predetermined time” refers to a time sufficient for the platen cover 12 to acquire output data from the line sensor 106 at the second position.

In ACT8, Make a constant (calculated) the placed document size on the contact glass 11. FIG. 11 shows a flowchart of more specific processing of ACT8.

  That is, in ACT 81 of FIG. 11, the first-stage output data stored in ACT 3 and the second-stage output data stored in ACT 6 are read and compared with both output data. Then, it is determined whether the first-stage output data and the second-stage output data are inverted.

  If the output data is inverted (Yes), the process proceeds to ACT 82, and the first stage output data is set as size determination information, and the process proceeds to ACT 84.

  When the output data is not inverted (No), the process proceeds to ACT 83, the size determination information is obtained from the first and second stage output data, and the process proceeds to ACT 84.

  Based on the size determination information of ACT 82 or ACT 83, ACT 84 refers to the reference table and proceeds to ACT 85. In ACT 85, it is determined whether the size is fixed. If the size cannot be determined (No), that effect is displayed (ACT 86). If the size can be determined (Yes), the size detection operation is terminated.

  In ACT1, when the start switch is turned on, the process proceeds to ACT9.

  In ACT 9, it is detected whether the open / close position sensor 13 detects the first position of the platen cover 12. When the first position of the platen cover 12 is detected, that is, when the platen cover 12 remains open, the process proceeds to ACT10.

  In ACT10, the detection operation in the first stage is executed in the same manner as in ACT3. After performing the first detection operation, the process proceeds to ACT11.

  In ACT 11, the document size is determined. That is, the first-stage output data stored in ACT 10 is used as size determination information. Based on the document size determination information, the size is determined with reference to the reference table.

Figure 1 2 to 17, based on the detection result in the detection result and the second stage in the first stage is an explanatory diagram for explaining a document size detection example for the control unit 82.

Figure 1 The document detection at 2 to 17, Gu the case where the thickness of the document may thick as in the book of normal paper, it shall underlying document and what the blackish or dark color whitish Judgment was made separately. The following items were assumed as the premise for detecting the document size.

(1) The color of the platen cover is white.
(2) When the platen cover 12 is open, the line sensor 106 determines that the output is smaller than a certain threshold (the amount of received light is large, for example, not black) that there is a document [1].
(3) When the platen cover 12 is in the middle of closing, the line sensor 106 determines that a place where the output is larger than a certain threshold value (a place where the amount of received light is large, for example, white) is “no original [0]”, and the output A place where the document is smaller than a certain threshold (a place where the amount of received light is small, for example, a place where it is not white) is determined to be a document [1].
(4) As the determination result of the line sensor 106, the size determination information is preferentially given to the presence of document [1] determined either when the platen cover 12 is open or when the platen cover 12 is being closed. However, when the determination result is reversed between when the platen cover 12 is open and when the platen cover 12 is being closed, the determination result when the platen cover 12 is open is used as size determination information.
(5) When the platen cover 12 is open, the position sensor APS determines that a position where the output is smaller than a certain threshold value (the amount of received light is small, for example, black) is no document [0], and the output is A place larger than the above threshold (a place where the amount of received light is large, for example, a place where it is not black) is determined to be a document [1].

Based on the above assumptions, the base in the usual document of FIG. 1 2 (a) will be described for the case of whitish example.

  The detection result of the line sensor 106 at the first detection positions PS1 to PS5 is [11100], and the detection result of the position sensor APS is [1]. The detection result of the line sensor 106 at the detection positions PS1 to PS5 in the second stage is [00000]. The detection result of the position sensor APS is [no detection]. “No detection” means that the document cannot be detected at the position where the position sensor APS is installed.

  In this case, the control unit 82 determines that the detection result of the detection positions PS1 to PS5 is “inverted” in the second stage with respect to the first stage in ACT8 of FIG. The controller 82 takes the difference between the first stage and the second stage in ACT9. As the size confirmation information, the detected position is “A5” or “A4-R” of PS3, and the document is “present” at the position of the position sensor APS. As shown in FIG. 9, among “A5” and “A4-R”, the document size when there is a document at the position of the position sensor APS is “A4-R”.

Then, the underlying regular document of FIG. 1 2 (b) will be described for the case of black-based (or dark color).

  The detection result of the line sensor 106 at the first-stage detection positions PS1 to PS5 is [00000], and the detection result of the position sensor APS is [1]. The detection result of the line sensor 106 at the detection positions PS1 to PS5 in the second stage is [11100], and the detection result of the position sensor APS is [No detection].

As the judgment at ACT 8 in FIG. 10, the first stage and the second stage are “not inverted”, so the difference between the first stage and the second stage is taken in ACT 9. The length determination information, in the same manner as FIG. 1 2 (a), the "A5" or "A4-R" detection position PS3, the original position of the position sensor APS becomes "Yes". As shown in FIG. 9, among “A5” and “A4-R”, the document size when there is a document at the position of the position sensor APS is “A4-R”.

  An example in which the background of the normal document in FIG. 13A is white is described. The detection result at the first-stage detection positions PS1 to PS5 is [11111], and the detection result of the position sensor APS is [0]. The detection result of the line sensor 106 at the second detection positions PS1 to PS5 is [00000], and the detection result of the position sensor APS is [No detection].

  In this case, the determination of the detection results of the detection positions PS1 to PS5 in the second stage in FIG. 10ACT8 is “with inversion”. In ACT10 in FIG. 10, the detection result at the first stage is used as size determination information. Accordingly, as the size confirmation information, the detection position is “A4” or “A3” of PS5, and the document is “None” at the position of the position sensor APS. As shown in FIG. 9, among “A4” and “A3”, the document size when there is no document at the position of the position sensor APS is “A4”.

  Next, a case where the background of the normal document in FIG. 13B is a black (or dark) example will be described.

  The detection result at the first-stage detection positions PS1 to PS5 is [00000], and the detection result of the position sensor APS is [0]. The detection result of the line sensor 106 at the detection positions PS1 to PS5 in the second stage is [11111], and the detection result of the position sensor APS is [No detection].

  As a determination in FIG. 10ACT8, the detection results of the detection positions PS1 to PS5 are “inverted” in the first stage and the second stage. Therefore, in ACT 10 of FIG. 10, the detection result at the first stage is used as size determination information. The detection result of the detection positions PS1 to PS5 in the first stage is [00000]. The size determination information is “determination addition” in which detection positions PS1 to PS5 and position sensor APS cannot be detected. In this case, the display unit 86 notifies that the size cannot be detected in the ACT 13 of FIG.

  In the example in which the background of the normal document in FIG. 14A is white, the detection results of the first-stage detection positions PS1 to PS5 are [11110], and the detection result of the position sensor APS is [1]. The detection result of the detection positions PS1 to PS5 in the second stage is [00000]. This detection result is “not inverted” for the first stage. In this case, as shown by ACT9 in FIG. 10, there is a difference between the first stage and the second stage. As the size confirmation information, the detection results of the detection positions PS1 to PS5 are [11110], and the detection result of the position sensor APS is [1]. Therefore, the document size is “B4”.

  Similarly, when the background of the normal document in FIG. 14B is black (or dark), the detection results of the first-stage detection positions PS1 to PS5 are [00000], and the detection result of the position sensor APS. Is [1]. The detection result of the detection positions PS1 to PS5 in the second stage is [11110], and the detection result of the position sensor APS is [No detection]. The difference between the first stage and the second stage is taken in FIG. 10ACT9. As the size determination information, the detection results of the detection positions PS1 to PS5 are [11110], and the detection result of the position sensor APS is [1]. Therefore, the document size is “B4”.

  An example in which the background of the book document in FIG. 15A is white is described. The detection result of the line sensor 106 at the first-stage detection positions PS1 to PS5 is [11100], and the detection result of the position sensor APS is [1]. The detection result of the line sensor 106 at the detection positions PS1 to PS5 in the second stage is [00011], and the detection result of the position sensor APS is [No detection].

  The control unit 82 in this case determines “invert” in FIG. 10ACT8, and uses the detection result of the first step in ACT10 as size confirmation information. As a result, the detection position in the main scanning direction is “A5” or “A4-R” of PS3, and the document is “present” at the position of the position sensor APS. As shown in FIG. 9, among “A5” and “A4-R”, the document size when there is a document at the position of the position sensor APS is “A4-R”.

  In the example in which the background of the book document in FIG. 15B is black (or dark), the detection result at the first-stage detection positions PS1 to PS5 is [00000], and the detection result of the position sensor APS is [ 1]. The detection result of the line sensor 106 at the detection positions PS1 to PS5 in the second stage is [11111], and the detection result of the position sensor APS is [No detection].

  Since the first and second stages are “inverted”, the detection result of the first stage is used as size determination information. The detection result of the detection positions PS1 to PS5 in the first stage is [00000]. Therefore, the size determination information is “determination addition” because there is no detection result of the detection positions PS1 to PS5. In this case, the display unit 86 notifies that the size cannot be detected.

  An example in which the background of the book document in FIG. 16A is white is described. The detection result of the first-stage detection positions PS1 to PS5 is [11111], and the detection result of the position sensor APS is [0]. The detection result of the detection positions PS1 to PS5 in the second stage is [00000], and the detection result of the position sensor APS is [No detection].

  In this case, the control unit 82 determines that the second stage “inverts” the first stage, and uses the detection result of the first stage as size confirmation information. As a result, the detected position in the main scanning direction is “A4” or “A3” of PS5, but the document is “None” at the position of the position sensor APS. Therefore, the size confirmation information is “A4”.

  When the background of the book document in FIG. 16B is black (or dark), the detection result of the first-stage detection positions PS1 to PS5 is [00000], and the detection result of the position sensor APS is [1]. ]. The detection result of the detection positions PS1 to PS5 in the second stage is [11111], and the detection result of the position sensor APS is [No detection].

  In this case, the control unit 82 determines that the second stage “inverts” the first stage, and uses the detection result of the first stage as size confirmation information. As a result, the detection result of the detection position in the main scanning direction is [00000]. Since there is no size determination information in the main scanning direction, this is “addition of judgment”. In this case, the display unit 86 notifies that the document size cannot be detected.

  An example in which the background of the book document in FIG. 17A is white is described. The detection result of the first-stage detection positions PS1 to PS5 is [11110], and the detection result of the position sensor APS is [0]. The detection result of the detection positions PS1 to PS5 in the second stage is [00001], and the detection result of the position sensor APS is [No detection].

  In this case, the control unit 82 determines that the second stage “inverts” the first stage, and uses the detection result of the first stage as size confirmation information. As a result, the detection position in the main scanning direction is “B5” or “B4” of PS4, but the document is “present” at the position of the position sensor APS. Therefore, the size confirmation information is “B4”.

  When the background of the book document in FIG. 17B is black (or dark color), the detection results of the first-stage detection positions PS1 to PS5 are [00000], and the detection result of the position sensor APS is [1]. ]. The detection result of the detection positions PS1 to PS5 in the second stage is [11111], and the detection result of the position sensor APS is [No detection].

  In this case, the control unit 82 determines that the second stage “inverts” the first stage, and uses the detection result of the first stage as size confirmation information. As a result, the detection result of the detection position in the main scanning direction is [00000]. Since there is no size determination information in the main scanning direction, this is “addition of judgment”. In this case, the display unit 86 notifies that the document size cannot be detected.

  As described above, the document size in the main scanning direction is determined by the line sensor, and the document size in the sub-scanning direction can be detected by a common position sensor. In addition, the document size determination information is obtained from information obtained when the platen cover is opened and during the closing process. As a result, not only the detection of a normal document, but also the document size can be detected for a thick document such as a book with exception.

  In the above-described example, when the original size cannot be detected with a normal original, the original is A4 and the background is black. If the size cannot be detected with a book document, the document is A4-R, A4, and B4, and the background is black. In other cases, the document size can be detected. Further, even when the document size cannot be detected, it is possible to notify the user of non-detectable information through the display unit, and the user can obtain the information and make a smooth selection by manual operation.

  In this embodiment, when detecting the document size, the detection position information in the main scanning direction when the platen cover is being opened and closed is read by the line sensor in the first stage and the second stage, and the respective detection results are detected. Based on the above, it was determined whether the first step or the difference between the first and second steps was taken. Thus, with some exceptions, it is possible to detect the size of an original or a thick original when the background is black without changing the hardware configuration.

(Second Embodiment)
Next, a second embodiment according to the document reading apparatus will be described.

  In this embodiment, when the open / close position sensor 13 detects that the platen cover 12 is in the middle of closing at the time of detection in the second stage, it is determined that the document is a thick document. When it is determined that the output of the opening / closing position sensor 13 at the second stage is in the middle of closing, the detection result at the first stage is determined as document size information.

  Also in this embodiment, when the document size is detected, the signal in the open / closed state of the platen cover position is read by the line sensor, and the detection result of the open state of the platen cover and the state in which the platen cover is being closed The document size is detected by combining the detection results of. As a result, it is possible to reliably detect the document size without changing hardware or man-hours.

  The present invention is not limited to the above-described embodiment. For example, when the detection is not possible, the user is notified via the display unit. However, the notification may be performed by voice, or the voice may be used in combination.

  Although several embodiments have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, combinations, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

100 Digital Copier 10 Scanner 50 Printer 11 Contact Glass 12 Platen Cover 13 Open / Close Position Sensor 133 Shutter 133a First Shutter 133b Second Shutter 134 Rotating Member 135 First Photointerrupter 136 Second Photointerrupter 82 Control Unit D Documents PS1 to PS5 Detection position APS Position sensor

Claims (3)

A document table on which the document is placed;
A line sensor for detecting the size of the document in the main scanning direction based on an output signal obtained by scanning the main scanning direction of the document placed on the document table;
The first position opened with respect to the document table and the second position in the middle of closing from the first position are supported so as to be openable and closable, and placed on the document table. A platen cover to hold the original,
The platen cover is the first position, a document reading apparatus and a closing position sensor for detecting that it is in the second position,
The detection result of the first stage of the line sensor when the platen cover is detected by the opening / closing position sensor to be in the first position, and the platen cover is in the second position by the opening / closing position sensor. When the detection result of the second stage of the line sensor is acquired, the detection result of the first stage is compared with the detection result of the second stage, and both detection results are inverted In this case, the detection result of the first stage is the size detection result, and if the detection results are not reversed , the difference between the detection results of the first stage and the second stage is the size detection result. Reader.   When the detection result of the second stage is a detection result when the position sensor detects that the second stage is in the second position, the detection result of the second stage is compared with the detection result of the first stage. The document reading apparatus according to claim 1, wherein it is determined whether or not the document is reversed, and when the document is reversed, the document size is determined based on the detection result of the first stage. A position sensor for detecting the position of the document in the sub-scanning direction of the document;
The position sensor detects whether the document detected by the line sensor is placed vertically or horizontally, and the detection result of the line sensor and the position sensor are combined to obtain a final document size detection result. Or the document reading device described in 2;

Images