JP2016092478A - Image reader and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately discriminate an original size of an original even if a tilt correction function is effective.SOLUTION: An image reader includes: an original transportation section; a tilt angle detection section; a reading region setting section; an image reading section; a tilt correction section; a storage section; and an original size discrimination section. The storage section stores size discrimination information which shows a relation between the original size of the original and a length of at least one direction of image data. The reading region setting section makes a reading region which is set when tilt correction processing is performed to be larger than a reading region which is set when the tilt correction processing is not performed. The original size discrimination section detects the original size of the original by using the length of at least one direction of the image data and the size discrimination information when the tilt correction processing is not performed, and detects the original size of the original by using a tilt angle in addition to the length of at least one direction of the image data and the size discrimination information when the tilt correction processing is performed.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an image reading apparatus and an image forming apparatus including the image reading apparatus, and more particularly to a technique for determining a document size of a document transported by a document transport unit.

  In recent years, an image reading apparatus having a so-called mixed reading function has appeared. In the image reading apparatus, originals of different original sizes placed on the original placement table are conveyed by an original conveying apparatus, and the originals of different original sizes are read at a time by the original being read by the image reading unit. I'm reading.

  Here, in mixed reading, since originals of different original sizes are placed on the original placement table, the originals may be conveyed in a state inclined with respect to the original conveying direction. In an image reading apparatus equipped with an inclination correction function that performs an inclination correction process according to the inclination of an original, even when the original is read in an inclined state in mixed reading, the orientation of the image data is corrected to the correct orientation. (For example, refer to Patent Document 1).

JP 2013-077954 A

  When the tilt correction function is effective, it is necessary to set a wide reading range in order to prevent image loss from occurring in image data subjected to tilt correction processing. However, in this case, since the reading area of the document becomes wider than when the document is conveyed in a normal state, there is a problem that the document size of the document cannot be accurately determined.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to enable accurate determination of the document size of a document even when the tilt correction function is effective.

  An image reading apparatus according to one aspect of the present invention includes a document placing table, and includes a document conveying unit that conveys a document placed on the document placing table, and an inclination angle of the document conveyed from the document conveying unit. An inclination angle detecting unit to detect, a reading region setting unit for setting a reading region of a document conveyed from the document conveying unit, and the reading region set by the reading region setting unit to read the document and obtain image data An image reading unit to be generated, an inclination correction unit that performs an inclination correction process on the image data generated by the image reading unit in accordance with the inclination angle, an original size of the original, and at least one direction of the image data And a document size discriminating unit for discriminating the document size of the document, and the reading area setting unit executes the tilt correction process. The reading area to be set in the case where the inclination correction processing is not performed, and the document size determination unit is configured to make the image data of the image data when the inclination correction processing is not executed. When the document size of the document is determined using the length in at least one direction and the size determination information and the tilt correction process is executed, the length of the image data in at least one direction and the size determination information are In addition, the image reading apparatus determines the document size of the document using the tilt angle.

  An image forming apparatus according to another aspect of the present invention includes the image reading apparatus described above and an image forming unit that forms an image on recording paper based on image data generated by the image reading apparatus. Device.

  According to the present invention, it is possible to accurately determine the document size of a document even when the tilt correction function is effective.

1 is a perspective view illustrating an image forming apparatus including an image reading apparatus according to an embodiment of the present invention. 1 is a side sectional view showing a structure of an image reading apparatus according to an embodiment of the present invention. FIG. 3 is a plan sectional view showing the arrangement positions of various sensors installed in the document conveying section of the image reading apparatus according to the embodiment of the present invention. 1 is a functional block diagram schematically showing main internal configurations of an image reading apparatus and an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the reading area set by the reading area setting part of the image reading apparatus concerning one Embodiment of this invention. (A) is a figure which shows an example of the size discrimination | determination information memorize | stored in the memory | storage part of the image reading apparatus concerning one Embodiment of this invention, (B)-(D) is an example of the content of size discrimination | determination information. FIG. 6 is a flowchart illustrating a flow of a mixed document reading operation by the image reading apparatus according to the embodiment of the present invention.

  Hereinafter, an image reading apparatus and an image forming apparatus including the same according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an image forming apparatus including an image reading apparatus according to an embodiment of the present invention.

  The image forming apparatus 1 is a multifunction machine having a plurality of functions such as a facsimile communication function, a copy function, a printer function, and a scanner function. As shown in FIG. 1, the image forming apparatus 1 is generally configured by an apparatus main body 80 and an image reading apparatus 10 disposed above the apparatus main body 80.

  A paper feed unit 82, an image forming unit 84, and the like are accommodated in a housing 81 that constitutes the outline of the apparatus main body 80.

  The paper supply unit 82 includes a paper supply cassette (not shown) that stores paper (recording paper) and a feeding roller (not shown), and the paper stored in the paper supply cassette is provided inside the housing 81. The paper is fed out toward the paper transport path.

  The image forming unit 84 includes a photosensitive drum (not shown), a charging device (not shown), an exposure device (not shown), a developing device (not shown), and the like. The image forming unit 84 forms a toner image based on image data generated by the image reading apparatus 10 reading a document on the photosensitive drum through charging, exposure, and development processes. The paper conveyed from the paper supply unit 82 is transferred to the discharge tray 88 after the toner image formed on the photosensitive drum is transferred and subjected to a fixing process.

  An operation unit 85 is disposed on the front surface of the casing 81 of the apparatus main body 80. The operation unit 85 includes a display unit 851 including a liquid crystal display (LCD) and an organic light-emitting diode (OLED) display, and an operation on a screen displayed on the display unit 851. Are provided with a plurality of operation keys 852.

  Based on the operation screen displayed on the display unit 851, an image reading instruction, an image forming instruction, or the like is input by a user operation input using the operation key 852 or the like. The input instruction is received by the receiving unit 102 (see FIG. 4).

  FIG. 2 is a side sectional view showing the structure of the image reading apparatus 10 according to the embodiment of the present invention. The image reading apparatus 10 includes an image reading unit 30 and a document conveying unit 20 disposed above the image reading unit 30.

  The image reading unit 30 includes a reading unit 40 including a CCD (Charge Coupled Device), an image irradiation lamp, and the like, a document table 52 formed of a transparent member such as glass, and a reading slit 53. The reading unit 40 is moved by a reading unit driving unit (not shown) having a stepping motor, gears, and the like.

  In the fixed document reading, the reading unit driving unit moves the reading unit 40 in a sub-scanning direction from a predetermined reading start position, and reads a document placed on the document table 52. On the other hand, in document conveyance reading, the reading unit 40 is fixed at a predetermined position on the back surface of the reading slit 53 by the reading unit driving unit, and the document conveyed toward the reading slit 53 by the document conveying unit 20 is read.

  As described above, the document conveying unit 20 conveys the document to the reading slit 53 that is the reading area of the reading unit 40. The document transport unit 20 includes a document placing table 21 on which a document is placed, a document transport mechanism 22 that transports a document placed on the document placing table 21, and a document discharge unit 23 that ejects an image-read document. And. The document transport mechanism 22 includes a paper feed roller 60, a registration roller pair 65, a document detection sensor 66, a separation roller 67, a paper discharge roller pair 68, and a document transport path 601.

  The paper feed roller 60 and the separation roller 67 are disposed in contact with each other. The paper feed roller 60 and the separation roller 67 convey the original document toward the registration roller pair 65 while nipping the original document on the original document placing table 21 one by one while holding the original document by the nip portion of both rollers.

  The registration roller pair 65 is a roller that adjusts the timing of conveying the document to the reading slit 53. The registration roller pair 65 conveys the document toward the reading slit 53 while holding the document between the nip portions of both rollers.

  At the position of the reading slit 53, the image on the surface of the document from the leading end to the trailing end of the document transported in this way is read by the reading unit 40. The document that has passed through the reading slit 53 is received by the paper discharge roller pair 68 and is discharged to the document discharge unit 23 by the paper discharge roller pair 68.

  Here, a plurality of sensors for detecting a document are arranged inside the document transport unit 20. FIG. 3 is a cross-sectional plan view showing the arrangement positions of various sensors installed in the document conveying section 20. As shown in the figure, a guide plate 29 that is slidable in the main scanning direction (a direction orthogonal to the transport direction) and a guide plate detection sensor that outputs a signal indicating the slide position of the guide plate 29 are provided on the document table 21. 27 are arranged. The document length detection unit 105 (see FIG. 4) detects the length of the document in the main scanning direction (length in the main scanning direction) based on the signal output from the guide plate detection sensor 27.

  In addition, a document detection sensor 66 is disposed between the position where the paper feed roller 60 and the separation roller 67 are disposed in the document conveyance path 601 and the position where the registration roller pair 65 is disposed. The document detection sensor 66 is a line sensor in which two optical sensors 661 and 662 are juxtaposed in a direction orthogonal to the conveyance direction. The optical sensors 661 and 662 of the document detection sensor 66 output a high level signal when a document is detected, and output a low level signal when a document is not detected. The document length detection unit 105 multiplies the time during which high-level signals are output from the optical sensors 661 and 662 of the document detection sensor 66 by the document transport speed, thereby subtracting the document in the document transport path 601. A length (sub-scanning direction length) in the scanning direction (conveyance direction) is detected.

  Here, when the inclination angle of the document with respect to the sub-scanning direction increases, the timing at which the optical sensor 661 switches from the low level signal to the high level signal and the timing at which the optical sensor 662 switches from the low level signal to the high level signal. The difference increases. Similarly, when the inclination angle of the document with respect to the sub-scanning direction increases, the timing at which the optical sensor 661 switches from the high level signal to the low level signal and the timing at which the optical sensor 662 switches from the high level signal to the low level signal. The difference increases. That is, there is a proportional relationship between the tilt angle of the document and the difference in timing when the low level signal is switched to the high level signal between the optical sensors 661 and 662 and the difference in timing when the high level signal is switched to the low level signal. Holds. The tilt angle detection unit 104 (see FIG. 4) is based on the difference in timing when the low level signal switches from the low level signal to the high level signal between the optical sensors 661 and 662, or the difference in timing when the high level signal switches to the low level signal. Detects the tilt angle of the document.

  Further, a plurality of optical sensors 641 are arranged in a direction orthogonal to the conveyance direction between the arrangement position of the paper feed roller 60 and the separation roller 67 and the arrangement position of the registration roller pair 65 in the document conveyance path 601. A different width detection sensor 64 is provided. The different width detection sensor 64 is a sensor used when mixed reading of a document is performed. Each optical sensor 641 of the different width detection sensor 64 outputs a high level signal when a document is detected, and outputs a low level signal when a document is not detected. The document length detection unit 105 detects the length of the document in the main scanning direction based on a signal output from the different width detection sensor 64 when the mixed reading of the document is performed.

  Next, the internal configurations of the image reading apparatus 10 and the image forming apparatus 1 will be described. FIG. 4 is a functional block diagram schematically showing main internal configurations of the image reading apparatus 10 and the image forming apparatus 1 according to the embodiment of the present invention. Note that a description of the already described configuration is omitted.

  The storage unit 70 is a large-capacity storage device such as an HDD (Hard Disk Drive).

  The control unit 100 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. The control unit 100 is configured such that the control unit 101, the receiving unit 102, the tilt angle detecting unit 104, the document length detecting unit 105, the reading are executed by the CPU executing a control program stored in the ROM or HDD. It functions as an area setting unit 107, a document size determination unit 108, and an inclination correction unit 109. In addition, each said structure of the control unit 100 may be each comprised by the hard circuit irrespective of the operation | movement based on the above-mentioned control program.

  The control unit 101 controls overall operation of the image reading apparatus 10 and the image forming apparatus 1. The control unit 101 is connected to the image reading apparatus 10, the storage unit 70, the paper feeding unit 82, the image forming unit 84, the operation unit 85, and the like. Send or receive signals or data.

  The accepting unit 102 performs an image reading instruction, an image forming instruction, an execution instruction for the mixed reading process, and a sub-scanning direction based on a user operation input using the operation key 852 or the like according to the operation screen displayed on the display unit 851. An execution instruction or the like for the tilt correction process according to the tilt angle of the document is received.

  The reading area setting unit 107 has a function of setting a document reading range by the image reading unit 30 based on the length of the document in the sub-scanning direction and the main scanning direction detected by the document length detection unit 105.

  FIG. 5A and FIG. 5B are diagrams illustrating the reading area set by the reading area setting unit 107. FIG. 5A shows a reading area when the tilt correction function is disabled, and FIG. 5B shows a reading area when the tilt correction function is enabled.

  As shown in FIG. 5A, when the tilt correction function is invalid, the reading area setting unit 107 is an area determined from the length of the document in the sub-scanning direction and the main scanning direction detected by the document length detection unit 105. An area having the same size as or a slightly larger area is set as the reading area A1. In the example shown in FIG. 5A, the length in the sub-scanning direction of the reading area A1 is L1, and the length in the main scanning direction is W1.

  On the other hand, when the tilt correction function is effective, it is necessary to set a wide reading range in order to prevent image loss from occurring in the image data subjected to the tilt correction processing. For this reason, as shown in FIG. 5B, the reading area setting unit 107 has an area larger than the area determined from the length of the document in the sub-scanning direction and the main scanning direction detected by the document length detection unit 105. Set as reading area A2. As a result, the reading area A2 set when the inclination correction function is valid is wider than the reading area A1 set when the inclination correction function is invalid (W2 ≧ W1, L2 ≧ L1). .

  The inclination correction unit 109 executes an inclination correction process on the image data generated by the image reading unit 30 reading a document. Specifically, the inclination correction unit 109 executes a rotation process, a size adjustment process, and the like according to the inclination angle detected by the inclination angle detection unit 104. Note that the above-described processing by the inclination correction unit 109 is performed when the reception unit 102 receives an instruction to execute inclination correction processing and the inclination correction function is valid.

  The document size determination unit 108 is a document of a document conveyed by the document conveyance unit 20 based on at least one length of the image data detected by the conveyance direction length detection unit 105 and predetermined size determination information. Has a function to determine the size.

  The storage unit 70 stores the size determination information for each inclination angle of the document. Each size discrimination information indicates the relationship between the length of at least one direction of image data and the document size of the document when the document is tilted by each tilt angle.

  FIG. 6A is a diagram illustrating an example of the size determination information stored in the storage unit 70. In the example shown in this figure, the storage unit 70 stores the relationship between the document size and the length of the image data in the sub-scanning direction at an inclination angle of 0 °, an inclination angle of ± 1 °, an inclination angle of ± 2 °, and an inclination angle of ± 3 °. The size discrimination information shown is stored.

  6B, 6C, and 6D show the relationship between the length of the image data in the sub-scanning direction and the document size when the length of the image data in the main scanning direction is 287 mm or more. Yes. The document size determination unit 108 selects size determination information used for document size determination from among a plurality of size determination information stored in the storage unit 70 based on the document inclination angle detected by the inclination angle detection unit 104. . The document size determination unit 108 determines the document size of the document by comparing the length of the image data in the sub-scanning direction with the selected size determination information. For example, when the inclination angle of the document is 2 ° and the length of the image data in the sub-scanning direction is 376.2 mm, the document size determination unit 108 determines that the document size is B4.

In the above description, the document size determination unit 108 selects one size determination information from a plurality of size determination information according to the inclination angle, and the selected size determination information and at least one direction of the image data. Although the case where the document size of the document is determined by comparing with the length has been described, the present invention is not necessarily limited to this case. The document size determination unit 108 corrects the sub-scanning direction length of the image data using the tilt angle, and compares the corrected sub-scanning direction length with the size determination information with the tilt angle of 0 °. The original size may be determined. When the length in the sub-scanning direction before correction is M and the inclination angle is θ, the length N in the sub-scanning direction after correction is calculated by the following formula, for example.
N = M−Kθ (K> 0)

  In the above description, the document size determination unit 108 determines the document size of the document using the length of the image data in the sub-scanning direction. However, the present invention is not necessarily limited to this case. In the storage unit 70 or the like, size determination information indicating the relationship between the document size and the length in the main scanning direction for each inclination angle of the document is stored in advance, and the document size determination unit 108 stores the size determination information and the image data. The document size of the document may be determined by comparing with the length in the main scanning direction. The document size determination unit 108 may determine the document size of the document using both the sub-scanning direction length and the main scanning direction length of the image data.

  Next, the mixed reading operation of the original by the image reading apparatus 10 having the above configuration will be described. FIG. 7 is a flowchart showing the flow of the mixed reading operation of the original by the image reading apparatus 10.

  When the document reading operation is performed by the image reading apparatus 10, the receiving unit 102 determines whether or not a tilt correction instruction indicating that correction of image data according to the tilt angle of the document is to be executed has been received (step S10). .

  When accepting unit 102 accepts an inclination correction instruction (YES in step S10), that is, accepting unit 102 accepts both a mixed reading instruction and an instruction to execute an inclination correction process, and an original mixed reading function and inclination correction. If both functions are valid, the control unit 101 causes the document conveying unit 20 to start conveying the document placed on the document placing table 21 (step S11).

  The tilt angle detection unit 104 detects the tilt angle with respect to the document transport direction based on the signal output from the document detection sensor 66 (step S12).

  The document length detection unit 105 detects the length of the document in the main scanning direction and the length in the sub-scanning direction based on the signal output from the document detection sensor 66 (step S13).

  Then, the reading area setting unit 107 sets the reading range of the document by the image reading unit 30 based on the length in the main scanning direction and the length in the sub scanning direction of the document detected in the process of step S13 (step S15). .

  The control unit 101 causes the image reading unit 30 to read the document conveyed from the document conveying unit 20 within the document reading range set in the process of step S15 (step S16), and generate image data of the document (step S16). S17).

  The document size determination unit 108 determines the document size of the document by using the inclination angle of the document in addition to the length and size determination information of the image data generated in step S17 in the sub-scanning direction (step S18). . Specifically, the document size determination unit 108 selects one size determination information from a plurality of size determination information according to the inclination angle, and selects the selected size determination information and at least one direction of the image data. The size of the original is determined by comparing the length.

  The tilt correction unit 109 corrects the image data generated in step S17 based on the tilt angle of the document detected in step S12 (step S19), and stores the corrected image data in the storage unit 70 (step S19). Step S20).

  On the other hand, when the accepting unit 102 does not accept the tilt correction instruction (NO in step S10), that is, the accepting unit 102 accepts the mixed reading instruction, but does not accept the execution instruction of the tilt correction process, and the mixed document reading function is effective. If the tilt correction function is invalid, the image reading apparatus 10 executes a normal mixed document reading process (step S21). In the normal mixed document reading process, unlike the process of step S18, the document size determination unit 108 does not use the document inclination angle, and the size determination information of the length of the image data in the sub-scanning direction and the inclination angle of 0 °. Is compared to determine the document size of the document. In other words, the document size determination unit 108 does not use information on the tilt angle of the document in determining the document size.

  As described above, when documents having different document sizes are placed on the document placing table 21 and the placed document is transported by the document transport unit 20, the document is transported while being inclined with respect to the transport direction. There is a case. In this case, the reading area setting unit 107 sets a wide reading range of the document in the conveyance direction, and causes the image reading unit 30 to read the entire range of the document conveyed in an inclined state. However, there is a problem in that the document size of the document cannot be accurately determined because the reading range of the document in the transport direction is wider than when the document is transported in a normal state.

  On the other hand, in the image reading apparatus 10 according to the embodiment of the present invention, the reading area setting unit 107 sets the reading area to be set when the inclination correction process is executed when the inclination correction process is not executed. Larger than the reading area. When the document size determination unit 108 does not execute the tilt correction process, the document size determination unit 108 determines the document size of the document using at least one length of the image data and the size determination information, and the tilt correction process is performed. In addition to the length of at least one direction of the image data and the size determination information, the document size of the document is determined using the tilt angle. As described above, the image reading apparatus 10 according to the embodiment of the present invention determines the document size of the document using the tilt angle in addition to the length and size determination information of at least one direction of the image data. Even when the correction function is effective and the document reading area is set larger than usual, the document size of the document can be accurately determined.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made.

  For example, the configuration of the document detection sensor 66 shown in the above embodiment is an example, and the present invention is not necessarily limited to this case. The image reading apparatus 10 only needs to include a mechanism that can detect the inclination angle of the document and the length of the document in the sub-scanning direction in the document conveyance path 601.

  The control program described in the above embodiment may be recorded on a computer-readable non-transitory recording medium such as a hard disk, CD-ROM, DVD-ROM, or semiconductor memory. In this case, a computer-readable non-transitory recording medium that records the control program is an embodiment of the present invention.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Image reading apparatus 20 Original conveyance part 21 Original mounting base 22 Original conveyance mechanism 23 Original discharge part 27 Guide plate detection sensor 30 Image reading part 40 Reading unit 64 Different width detection sensor 66 Original detection sensor 70 Storage part 100 Control Unit 101 Control unit 102 Reception unit 104 Inclination angle detection unit 105 Document length detection unit 107 Reading area setting unit 108 Document size determination unit 109 Inclination correction unit

Claims (6)

A document transport unit having a document mounting table and transporting a document mounted on the document mounting table;
An inclination angle detecting unit for detecting an inclination angle of the original conveyed from the original conveying unit;
A reading area setting unit for setting a reading area of a document conveyed from the document conveying unit;
An image reading unit configured to read the original and generate image data in the reading region set by the reading region setting unit;
An inclination correction unit that performs an inclination correction process according to the inclination angle on the image data generated by the image reading unit;
A storage unit for storing size discrimination information indicating a relationship between the document size of the document and the length of at least one direction of the image data;
A document size determination unit for determining the document size of the document,
The reading area setting unit sets the reading area to be set when the tilt correction process is executed to be larger than the reading area to be set when the tilt correction process is not executed,
The document size determination unit determines the document size of the document by using at least one length of the image data and the size determination information when the inclination correction process is not executed, and the inclination correction process is executed. In this case, the image reading apparatus determines the document size of the document using the inclination angle in addition to the length of at least one direction of the image data and the size determination information. The storage unit stores the size determination information for each inclination angle,
Each size determination information indicates a relationship between the length of at least one direction of the image data and the document size of the document when the document is tilted by the tilt angle.
The document size determination unit selects one size determination information from the plurality of size determination information according to the tilt angle, and selects the selected size determination information and the length of at least one direction of the image data. The image reading apparatus according to claim 1, wherein the document size of the document is determined by comparing.   The document size determination unit corrects the length of at least one direction of the image data in accordance with the tilt angle, and compares the corrected length of at least one direction with size determination information. The image reading apparatus according to claim 1, wherein the document size is determined. A reception unit that receives an instruction to execute the inclination correction process;
When the reception unit receives the execution instruction, the inclination correction unit executes the inclination correction process, and when the reception unit does not receive the execution instruction, the inclination correction unit executes the inclination correction process. The image reading device according to claim 1, wherein the image reading device is not. The receiving unit further receives a mixed reading instruction for instructing reading of a document of a different document size;
The document size determination unit, in addition to the length of at least one direction of the image data and the size determination information, when the reception unit receives the mixed reading instruction in addition to the execution instruction of the inclination correction process. The image reading apparatus according to claim 4, wherein the document size of the document is determined using the tilt angle. An image reading apparatus according to any one of claims 1 to 5,
An image forming apparatus comprising: an image forming unit that forms an image on recording paper based on image data generated by the image reading apparatus.

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