JP5966279B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a technique for determining whether two image sensors are relatively inclined.

  Conventionally, the inclination of the image generated by reading the front surface of the document by the first image sensor and the inclination of the image generated by reading the back surface of the document by the second image sensor simultaneously with the first image sensor are calculated. A technique for detecting and correcting an image so that each inclination coincides with each other or changing and adjusting the mounting positions of these two image sensors to the apparatus main body so that each inclination coincides with each other is disclosed. (For example, refer to Patent Document 1).

Japanese Patent Laying-Open No. 2004-254166 (paragraphs 0007 and 0077)

The above-described conventional technique reads the front and back surfaces of the document at the same time. However, since the two image sensors are mounted apart from each other in the document transport direction, the front and back surfaces of the document can be simultaneously read. It may not be read. In this case, it may not be possible to accurately determine whether or not the two image sensors are relatively inclined only by the inclination of the image.
In the present specification, when it is determined whether or not two image sensors mounted apart from each other in the document transport direction are relatively inclined, the two image sensors are not inclined relatively. Regardless, it discloses a technique that can reduce misjudgment as being relatively inclined.

  An image reading apparatus disclosed in the present specification includes a transport unit that transports a document and a first image sensor, and the first image sensor has one surface of the document transported by the transport unit as the first image sensor. And a second image sensor provided downstream of the first image sensor in the conveyance direction of the document and conveyed by the conveyance unit. A second reading unit that reads the other side of the original that is read by the second image sensor and generates image data; and a second reading unit that detects the inclination of the original when being read by the first reading unit. A first document inclination detection unit; a second document inclination detection unit that detects the inclination of the document when it is read by the second reading unit; and at least one of the reading units. A fluctuation determining unit that determines whether or not the inclination of the original has changed during the reading of the original, and the fluctuation determining unit determines that the inclination of the original has not changed, and the first original When the inclination detected by the inclination detector and the inclination detected by the second document inclination detector do not match, the first image sensor and the second image sensor are relatively inclined. A sensor inclination determination unit that determines that the

  The variation determination unit may determine whether the inclination of the document has changed during the reading of the document by the reading unit for both the first reading unit and the second reading unit. Good.

  In the image reading apparatus, when the sensor inclination determination unit determines that the first image sensor and the second image sensor are relatively inclined, the two image sensors are relatively You may provide the alerting | reporting part which alert | reports to a user that it is inclined automatically.

  The variation determination unit determines whether at least one of the reading units has an edge representing a side of the document in the image data generated by the reading unit. It may be determined that the inclination of the original does not change during reading by the reading unit. If the original is not a straight line, it may be determined that the inclination of the original changes during reading by the reading unit.

  An image forming apparatus disclosed in the present specification includes a transport unit that transports a document and a first image sensor, and the first image sensor is provided on one side of the document transported by the transport unit. And a second image sensor provided downstream of the first image sensor in the conveyance direction of the document and conveyed by the conveyance unit. A second reading unit that reads the other side of the original that is read by the second image sensor and generates image data; and a second reading unit that detects the inclination of the original when being read by the first reading unit. A first document inclination detection unit; a second document inclination detection unit that detects the inclination of the document when it is read by the second reading unit; and at least one of the reading units. A fluctuation determining unit that determines whether or not the inclination of the original has changed during the reading of the original, and the fluctuation determining unit determines that the inclination of the original has not changed, and the first original When the inclination detected by the inclination detector and the inclination detected by the second document inclination detector do not match, the first image sensor and the second image sensor are relatively inclined. A sensor inclination determination unit that determines that the image data is generated, and a printing unit that prints the image data generated by the first reading unit and the image data generated by the second reading unit.

  The present invention can be realized in various modes such as an image reading method, an image reading program, a recording medium on which an image reading program is recorded, an image forming method, an image forming program, and a recording medium on which an image forming program is recorded. .

  According to the image reading apparatus and the image forming apparatus described above, when it is determined whether or not two image sensors that are mounted apart from each other in the document transport direction are relatively inclined, two image sensors are used. It is possible to reduce erroneous determination that the angle is relatively inclined even though the angle is not relatively inclined.

FIG. 2 is a schematic diagram illustrating a simplified electrical configuration of the multifunction peripheral according to the first embodiment. FIG. 3 is a schematic diagram showing a part of a reading unit in a simplified manner. The schematic diagram for demonstrating the definition of a main scanning edge and a subscanning edge. The schematic diagram which shows the relationship between the inclination of two image sensors, and the shape of an image. The schematic diagram which shows the relationship between the inclination of two image sensors, and the shape of an image. The schematic diagram which shows the relationship between the inclination of two image sensors, and the shape of an image. FIG. 5 is a schematic diagram illustrating an example in which the inclination of an original fluctuates during reading of the original. FIG. 10 is a schematic diagram illustrating another example in which the inclination of the document fluctuates during reading of the document. The flowchart which shows the flow of an inclination determination process.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS.
(1) Configuration of Multifunction Device FIG. 1 is a schematic diagram showing a simplified electrical configuration of a multifunction device 1 as an image forming apparatus according to the first embodiment. The multifunction machine 1 includes a control unit 10, an operation unit 11, a reading unit 12, a printing unit 13, and a communication interface unit 14.

  The control unit 10 includes a CPU 10a, a ROM 10b, and a RAM 10c. The CPU 10a controls each unit of the multifunction device 1 by executing a control program stored in the ROM 10b. The ROM 10b stores a control program executed by the CPU 10a and various data. The RAM 10c is used as a main storage device for the CPU 10a to execute various processes.

  The operation unit 11 includes a display device such as a liquid crystal display and various buttons. The user can perform various operations such as a document reading instruction and a copying instruction by operating the operation unit 11. The control unit 10 and the operation unit 11 are examples of a notification unit.

  The reading unit 12 is transported by a document tray 28 (see FIG. 2) on which documents are stacked, an ADF 27 (Auto Document Feeder, see FIG. 2) that transports documents stacked on the document tray 28 one by one, and the ADF 27. An image sensor that reads an original document and outputs an analog image signal, an A / D converter that converts an analog image signal output from the image sensor into digital data, a shading correction for digital data output from the A / D converter, The image processing circuit 12a is configured to perform various image processing such as gamma correction to generate image data.

  As will be described in detail later, the reading unit 12 includes a first image sensor 40a (see FIG. 4) for reading the front side of the document and a second image sensor 40b (see FIG. 4) for reading the back side of the document. These image sensors 40a and 40b are configured to be able to read both sides of a document. In the following description, when it is not specified which of the first image sensor 40a and the second image sensor 40b, it is simply referred to as the image sensor 40.

  In addition to the image processing described above, the image processing circuit 12a determines the relative inclination between the first image sensor 40a and the second image sensor 40b, determines the inclination of the document, and the image represented by the image data. It is configured to be able to correct the inclination of the image. The image processing circuit 12a is an example of a first document inclination detection unit, a second document inclination detection unit, a variation determination unit, and a sensor inclination determination unit.

The printing unit 13 converts the image represented by the image data generated by the reading unit 12 and the image represented by the image data received from the external device via the communication interface unit 14 onto a sheet such as printing paper by an electrophotographic method or an inkjet method. Print.
The communication interface unit 14 is communicably connected to an external device such as a personal computer or a portable information terminal via a communication network such as a LAN (Local Area Network) or the Internet. The communication interface unit 14 may be configured to be connected to an external device through a USB (Universal Serial Bus), a parallel line, or the like.

(2) Configuration of Reading Unit FIG. 2 is a schematic diagram showing a part of the reading unit 12 in a simplified manner. The housing 23 of the multifunction machine 1 is formed in a box shape, and a first platen glass 24 and a second platen glass 25 are juxtaposed on the upper part.
The document cover 26 is connected to the housing 23 so as to be able to rotate between a closed posture that covers the platen glasses and an open posture that opens the platen glasses. The document cover 26 is provided with a document tray 28, an ADF 27, a paper discharge tray 29, and the like.

  Inside the ADF 27, there are a separation roller 30, a suction roller 32 that is rotatably provided at a distal end portion of an arm 31 that is pivotally supported by a shaft that supports the separation roller 30, a plurality of conveyance rollers 33, 34, a paper discharge roller 35, and a plurality of driven rollers 36 in pressure contact therewith. The document is transported to these rollers and transported on the transport path 37, passing through the position read by the first CIS 21 and the position read by the second CIS 22, and discharged onto the discharge tray 29. . The ADF 27 is an example of a transport unit.

  The first CIS 21 (Contact Image Sensor) is fixed inside the ADF 27, and reads the back side of the document conveyed by the ADF 27 (the surface facing down on the document placed on the document tray 28). Output analog image signals. The first CIS 21 reads an original using an equal magnification optical system, and has a first image sensor 40a having a plurality of light receiving elements arranged in a straight line in a main scanning direction perpendicular to the paper surface (see FIG. 4). , A light source having light emitting diodes of RGB three colors, a rod lens array for forming an image of the reflected light reflected by the original on each light receiving element of the first image sensor 40a, and the like. The reading unit 12 that reads a document by the first CIS 21 is an example of a first reading unit.

  The second CIS 22 is accommodated in the housing 23 of the multifunction machine 1. As shown in the figure, the second CIS 22 is provided downstream of the first CIS 21 in the document transport direction. The second CIS 22 is provided on the surface of the document conveyed by the ADF 27 (the surface facing upward in the document placed on the document tray 28) and on the document placed on the first platen glass 24. Reads the surface facing downward and outputs an analog image signal.

In addition to the configuration of the first CIS 21, the second CIS 22 includes a carriage (not shown) on which these are mounted, and a transport mechanism (not shown) that reciprocates the carriage in the sub-scanning direction. The sub-scanning direction is a direction perpendicular to the main scanning direction and parallel to the surface of the first platen glass 24.
The second CIS 22 stops under the second platen glass 25 when reading a document conveyed by the ADF 27, and reads the document while sequentially switching the color of the light source. On the other hand, when reading a document placed on the first platen glass 24, the second CIS 22 reads the document while sequentially switching the color of the light source while moving at a constant speed in the sub-scanning direction. In the following description, the image sensor provided in the second CIS 22 is referred to as a second image sensor 40b (see FIG. 4). The reading unit 12 that reads a document by the second CIS 22 is an example of a second reading unit.

(3) Definition of main scanning edge and sub-scanning edge FIG. 3 is a schematic diagram for explaining the definition of main scanning edge and sub-scanning edge. The main scanning edge is a direction perpendicular to the conveyance direction among the four sides of the document 50 in the image 60 generated by reading the document 50 when the document 50 is conveyed in a direction parallel to one side of the document 50. The edges 60a and 60b representing the sides 50a and 50b are referred to. The sub-scanning edge refers to the edges 60c and 60d representing the sides 50c and 50d parallel to the transport direction.

  In the following description, the main scanning edge 60a representing the front side 50a of the document 50 in the transport direction is referred to as the main scanning edge on the leading side in the transport direction, and the main scanning edge 60b representing the side 50b on the rear end side in the transport direction of the document 50. This is called a main scanning edge on the rear end side in the carrying direction. In addition, simply referring to the main scanning edge means one of the main scanning edges. The same applies to the sub-scanning edge.

  Note that when the image sensor 40 is not attached at an inclination and the original is not inclined with respect to the transport direction, the main scanning edge is not inclined in the generated image, but the image sensor 40 is attached at an inclination. If the document is conveyed or the document is inclined, the main scanning edge is inclined in the generated image.

(4) Relationship Between Image Sensor Inclination and Image Shape The image sensor 40 may be attached to be inclined with respect to a direction perpendicular to the document transport direction. Hereinafter, the relationship between the relative inclination of the two image sensors 40 and the shape of the generated image will be described.

  FIG. 4 is a schematic diagram showing the shapes of the back image and the front image generated when the two image sensors 40 are attached without inclination and the document is conveyed without inclination. In this case, the main scanning edge 60a of the back surface image 60 generated by reading the back surface of the document 50 and the main scanning edge 61a of the front surface image 61 generated by reading the surface of the document are not inclined.

  In FIG. 5, the first image sensor 40a for reading the back side of the document is attached at an angle, while the second image sensor 40b for reading the surface of the document is not inclined and the document is conveyed without being inclined. It is a schematic diagram which shows the shape of the back surface image and surface image which are produced | generated in the case of being. In this case, the main scanning edge 60a of the back image 60 generated by reading the back surface of the document 50 is tilted, while the main scanning edge 61a of the front image 61 generated by reading the surface of the document 50 is not tilted.

  FIG. 6 is a schematic diagram showing the shapes of the back image and the front image that are generated when the two image sensors 40 are attached without being inclined but the document is being conveyed while being inclined. In this case, the main scanning edge 60a of the back surface image 60 and the main scanning edge 61a of the front surface image 61 are inclined together.

  FIG. 7 is a schematic diagram showing the shape of the back image and the front image generated when the two image sensors 40 are mounted without tilting and the tilt of the document fluctuates during reading of the back surface of the document. . In the case of the example shown in FIG. 7, the back image 60 generated by reading the back side of the document 50 does not tilt the main scanning edge 60 a when reading the back side of the document 50 starts, but the tilt varies during reading. As a result, the sub-scanning edges 60c and 60d become curves.

(5) Determination of Relative Inclination of Two Image Sensors Next, determination of relative inclination of the two image sensors 40 will be described. Here, first, a case will be described where it is assumed that the inclination of the original does not change during the reading of the original.

As shown in FIG. 4, when the two image sensors 40a and 40b are attached without inclination and the document 50 is conveyed without inclination, the main scanning edge 60a of the back image 60 and the front image 61 are obtained. The main scanning edge 61a does not tilt.
For this reason, when the main scanning edge 60a of the back surface image 60 and the main scanning edge 61a of the front surface image 61 are not inclined together, the image processing circuit 12a is not inclined relative to the two image sensors 40a and 40b. Judge.

As shown in FIG. 5, the first image sensor 40 a that reads the back surface of the document 50 is tilted, while the second image sensor 40 b that reads the front surface of the document 50 is not tilted, and the document 50 is tilted. When the image is being conveyed, the main scanning edge 60a of the back image 60 is inclined, while the main scanning edge 61a of the front image 61 is not inclined.
For this reason, when the inclination of the main scanning edge 60a of the back surface image 60 and the inclination of the main scanning edge 61a of the front surface image 61 do not coincide, the image processing circuit 12a has the two image sensors 40a and 40b inclined relatively. Judge.

  Here, the first image sensor 40a that reads the back surface of the document 50 is tilted and the second image sensor 40b that reads the front surface of the document 50 is not tilted. The same applies to the case where the second image sensor 40b is not tilted and the second image sensor 40b is tilted. Alternatively, the same applies to the case where the first image sensor 40a and the second image sensor 40b are inclined together and the inclination directions are different from each other.

  Here, as shown in FIG. 5, an image (back image 60 in the case of FIG. 5) generated by reading the document 50 by the tilted image sensor 40 (first image sensor 40 a in the case of FIG. 5). Although the shape is not rectangular, the main scanning edges 60a and 60b and the sub-scanning edges 60c and 60d of the image are both straight lines. When the main scanning edge and the sub scanning edge are both straight lines, it is generally easy to correct the inclination of the image. Therefore, in this embodiment, both the main scanning edge and the sub scanning edge are straight lines even if the main scanning edge is inclined. If it is, the inclination of the image is corrected. In the following description, this correction is referred to as a first correction process.

  Here, the case where the document is conveyed without being inclined has been described as an example, but the same applies to the case where the document is conveyed while being inclined. Here, “the document is inclined” means that the sub-scanning edge of the image is inclined. Regardless of whether the image sensor 40 is tilted, the sub-scanning edge is not tilted when the document is not tilted, and the sub-scanning edge is tilted when the document is tilted. It can be determined whether or not. When the inclinations of the main scanning edges do not match, the image processing circuit 12a determines that the two image sensors 40a and 40b are relatively inclined regardless of whether the document is inclined.

  As shown in FIG. 6, the two image sensors 40 a and 40 b are attached without tilting. However, when the document 50 is transported with tilting, the main scanning edge 60 a of the back image 60 and the front image 61 are scanned. The main scanning edge 61a is inclined with the same inclination. For this reason, when the main scanning edge 60a of the back surface image 60 and the main scanning edge 61a of the front surface image 61 are tilted and the tilts coincide with each other, the image processing circuit 12a has two image sensors 40a and 40b. Judge that it is not inclined relatively.

  In this case, the main scanning edge is inclined along with the back image 60 and the front image 61. However, since the main scanning edge and the sub scanning edge are both straight lines, the back image 60 and the front image 61 are used in this embodiment. Correct the tilt of each. The correction in this case is different from the case of the example shown in FIG. 5 described above, and the inclination is corrected by rotating the entire image. In the following description, the process of correcting the tilt by rotating the image is referred to as a second correction process.

Further, even when the image sensors 40a and 40b are attached with an inclination, if the inclinations coincide with each other, the inclinations of the main scanning edges coincide with each other regardless of whether the image is conveyed with an inclination. Therefore, the image processing circuit 12a determines that the two image sensors 40a and 40b are not inclined relatively.
However, when the image sensor 40 is tilted, it cannot be corrected correctly even if the image is simply rotated. Therefore, the correction is performed by the first correction process. That is, in the second correction process, the correction by rotating the image and the correction by the first correction process are properly used. This proper use can be determined by whether or not the angle between the main scanning edge and the sub-scanning edge of the image is a right angle.

  As described above, when the inclination of the original does not change during the reading of the original, the relative inclination of the two image sensors 40 can be determined by examining the inclination of the main scanning edge of the generated image.

Next, a case will be described in which neither of the two image sensors 40a and 40b is inclined and the inclination of the original fluctuates during reading of the original.
As shown in FIG. 7, when the two image sensors 40 a and 40 b are attached without inclination and the inclination of the document 50 fluctuates during reading of the back surface of the document 50, reading of the back surface of the document 50 starts. Although the main scanning edge 60a is not tilted at the time, the sub-scanning edges 60c and 60d of the back image 60 become curves due to the tilt variation during reading.

  In this case, if the inclination of the image sensor 40 and the inclination of the document 50 are determined using the inclination of the main scanning edge on the leading side in the conveyance direction, the main scanning edge 60a on the leading side in the conveyance direction of the back image 60 is inclined. Although the main scanning edge 61a on the front end side in the transport direction of the surface image 61 is inclined, the pattern shown in FIG. 5 (to be precise, the reverse pattern of the pattern shown in FIG. 5) is determined. Specifically, it is determined that the two image sensors 40a and 40b are relatively inclined. However, actually, the two image sensors 40a and 40b are not tilted, and therefore, erroneous determination is made.

  On the other hand, if the relative inclination of the two image sensors 40 is determined using the inclination of the main scanning edge on the rear end side in the image conveyance direction, the main scanning edge 60b on the rear end side in the conveyance direction of the back image 60 is also on the front surface. The main scanning edge 61b on the rear end side in the conveyance direction of the image 61 is also inclined, and when these inclinations match, the pattern shown in FIG. 6 is determined. Specifically, it is determined that the two image sensors 40a and 40b are not relatively inclined.

However, in the example shown in FIG. 7, it can be determined correctly by using the inclination of the main scanning edge on the rear end side in the carrying direction, but in the case of pattern 4 shown in FIG. 8 described later, the main scanning edge on the rear end side in the carrying direction. If the image sensor 40a and 40b are tilted relative to each other, it is erroneously determined that the two image sensors 40a and 40b are relatively tilted.
That is, if the inclination of the document fluctuates during reading of the document, it may be determined correctly, but it may be erroneously determined, and the reliability of the determination result decreases.

  FIG. 8 is a schematic diagram showing another pattern in which the inclination of the original fluctuates during reading of the original. In FIG. 8, the example shown in FIG. It is assumed that the two image sensors 40a and 40b are not inclined in any of the patterns shown in FIG. Moreover, the pattern shown in FIG. 8 is an example, and there may be patterns other than these.

  In the pattern 2, the original is tilted when reading of the back side of the document is started by the first image sensor 40a that reads the back side of the document. However, the original is tilted by changing the tilt of the document during reading of the back side. This shows a case where the surface of the document is read by the second image sensor 40b in a state where it is not tilted and is not tilted.

  In the pattern 3, when the reading of the back side of the document is started by the first image sensor 40a, the document is not inclined and the inclination of the document does not change during the reading by the first image sensor 40a. A case where the inclination of the document fluctuates during reading of the surface of the document by the image sensor 40b is shown.

  In the pattern 4, when the first image sensor 40a starts reading the back side of the document, the document is tilted, and the tilt of the document does not change during the reading by the first image sensor 40a. This shows a case where the inclination of the document fluctuates during reading of the surface of the document by the sensor 40b, and the document is not tilted when reading of the surface of the document by the second image sensor 40b is completed.

For patterns 2 to 4 as well, there is a possibility that it may be erroneously determined whether or not the two image sensors 40 are relatively inclined only by examining the inclination of the main scanning edge of the generated image.
Therefore, the image processing circuit 12a determines whether or not the inclination of the document has changed while reading the back side of the document and whether or not the inclination of the document has changed while reading the front side of the document. When it is determined that the inclination of the document has not changed, the relative inclination of the two image sensors 40 is determined by examining the inclination of the main scanning edge.

  Here, whether or not the inclination of the original fluctuates during reading of the original can be determined by whether or not the sub-scanning edge of the image is a curve. Specifically, the image processing circuit 12a determines that the inclination of the document fluctuates during reading of the document when the sub-scanning edge is a curve, and the document when the sub-scanning edge is not a curve, that is, a straight line. It is determined that the inclination of the document does not fluctuate during reading.

(6) Flow of Inclination Determination Process FIG. 9 is a flowchart showing the flow of the inclination determination process for determining the relative inclination of the two image sensors 40. This process is started when the back side and the front side of one document are read and a back side image and a front side image are generated.

In S101, the image processing circuit 12a analyzes the back image and detects the main scanning edge and the sub scanning edge.
In S102, the image processing circuit 12a determines whether or not the inclination of the document has changed during the reading of the back side of the document by the first image sensor 40a. Specifically, the image processing circuit 12a determines whether the sub-scanning edge of the back image is a curve or a straight line. If it is a curve, it determines that it has changed, and if it is a straight line, it does not change. judge. The image processing circuit 12a proceeds to S103 when the inclination varies, and proceeds to S104 when it does not vary.

In S103, the image processing circuit 12a instructs the control unit 10 to display a message “Please read again.” When the control unit 10 is instructed to display a message from the image processing circuit 12a, the operation unit 11 is instructed. The message is displayed on the display device.
The reason for instructing the user to read the original again when the sub-scanning edge is a curved line is that the correction of the image is complicated when the sub-scanning edge is a curved line. In this embodiment, the sub-scanning edge is a curved line. In some cases, the image is not corrected, and the document is read again in the next reading in the expectation that the inclination of the document does not change during the reading.
When the inclination of the document fluctuates, the image may be corrected according to the curve of the sub-scanning edge.

In S104, the image processing circuit 12a analyzes the surface image and detects the main scanning edge and the sub scanning edge.
In S105, the image processing circuit 12a determines whether or not the inclination of the document fluctuates during reading of the surface of the document by the second image sensor 40b. Specifically, the image processing circuit 12a determines whether the sub-scanning edge of the surface image is a curved line or a straight line. If it is a curved line, the process proceeds to S103, and if it is a straight line, the process proceeds to S106.

  In S106, the image processing circuit 12a determines whether the inclination of the document when it is read by the first image sensor 40a and the inclination of the document when it is read by the second image sensor 40b are the same. judge. Specifically, the image processing circuit 12a determines whether or not the inclination of the main scanning edge of the back image and the inclination of the main scanning edge of the front image match, and if they match (FIG. 4 or FIG. 6), it is determined that the two image sensors 40 are not relatively inclined, and the process proceeds to S107. If they are not coincident (in the case illustrated in FIG. 5), it is determined that the two image sensors 40 are relatively inclined. Proceed to

In S107, the image processing circuit 12a determines whether or not the main scanning edge is tilted. If it is tilted (as shown in FIG. 6), the process proceeds to S108, and if it is not tilted (as shown in FIG. 4), the process is performed. Exit.
In S108, the image processing circuit 12a corrects the inclination of the back image and the front image by the second correction process described above.

In S109, the image processing circuit 12a corrects the inclination of the image on which the main scanning edge is inclined, either the back image or the front image, by the first correction process described above.
In S110, the image processing circuit 12a notifies the user that the two image sensors 40a and 40b are inclined relatively. Specifically, for example, the image processing circuit 12a instructs the control unit 10 to display a message “The image sensor is mounted at an angle. Please contact the administrator”. When the message display is instructed from 12a, the message is displayed on the display device of the operation unit 11. This notification may be performed by voice, for example.

  In this configuration, a mechanism for correcting the inclination of the image sensor 40 is provided instead of notifying the user that the image sensor 40 is attached at an inclination, and the inclination of the image sensor 40 is corrected by the mechanism. May be.

(7) Effects of the Embodiment According to the multifunction device 1 according to the first embodiment described above, when the document tilt changes while the document is being read by the image sensor 40, the two image sensors 40a and 40b are relatively tilted. Since it is not determined whether or not the two image sensors 40a and 40b are relatively inclined with respect to each other in the document conveyance direction, the two image sensors 40a and 40b It is possible to reduce misjudgment of being relatively inclined although it is not relatively inclined.

Even if the inclination of the document fluctuates during reading of the document, it may be determined correctly as described above, but it may be erroneously determined, so that the reliability of the determination result is lowered.
On the other hand, as described above, in the present invention, if the inclination of the document fluctuates during reading of the document, it is not determined whether or not the two image sensors 40a and 40b are relatively tilted. .

  Further, according to the multifunction device 1, since it is determined whether or not the inclination of the document fluctuates during the reading of the document by the reading unit for both the first reading unit and the second reading unit. The two image sensors 40a both in the case where the inclination of the original fluctuates during reading of the original by the sensor 40a and in the case where the inclination of the original fluctuates during reading of the original by the second image sensor 40b. , 40b can be accurately determined.

  Furthermore, according to the multifunction device 1, when it is determined that the first image sensor 40a and the second image sensor 40b are relatively inclined, the two image sensors 40a and 40b are relatively inclined. Therefore, the user can know that the two image sensors 40a and 40b are attached with a relative inclination.

  Further, according to the multifunction device 1, it is determined whether or not the edge representing the side of the document is a straight line. If the edge is a straight line, it is determined that the inclination of the document does not change during reading. By determining that the inclination of the document fluctuates, it can be determined whether or not the inclination of the document fluctuates during reading of the document.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In the above embodiment, the relative inclination of the two image sensors 40a and 40b is determined after the reading of the back side and the front side of the document is completed. Is a straight line or a curved line, and if it is a curved line, reading by the second image sensor 40b may not be performed.

  (2) In the above embodiment, the case where the inclination of the document is detected by analyzing the back image and the front image and detecting the main scanning edge has been described as an example. For example, the first image sensor 40a on the conveyance path 37 is described. A sensor for detecting the inclination of the original document may be provided in front of or behind the image sensor, and a sensor for detecting the inclination of the original document may be provided in front of or behind the second image sensor 40b. As a sensor for detecting the inclination of the document, for example, a plurality of photoelectric sensors arranged in a direction parallel to the extending direction of the image sensor 40 can be used.

  (3) In the above embodiment, when the two image sensors 40a and 40b are relatively tilted and the document is conveyed without tilting, that is, in the case of the example shown in FIG. In the example described above, the user is notified that the two image sensors 40 are relatively inclined in S110. However, the correction in S109 is not performed, and only the notification is performed in S110. May be. Alternatively, the correction in S109 may be performed and the notification in S110 may not be performed.

  (4) In the above-described embodiment, the case where the back side of the document is read first and the front side of the document is read later has been described as an example. However, the configuration may be such that the front side of the document is read first and the back side of the document is read later.

  (5) In the above embodiment, the multifunction device 1 has been described as an example of the image forming apparatus, but the present invention may be applied to an image reading apparatus.

  (6) In the above embodiment, the image processing circuit 12a has been described as an example of the first document inclination detection unit, the second document inclination detection unit, the variation determination unit, and the sensor inclination determination unit. It may be realized by an ASIC, or a part or all of these units may be executed by one or a plurality of CPUs.

DESCRIPTION OF SYMBOLS 1 ... Multifunction machine, 10 ... Control part, 11 ... Operation part, 12 ... Reading part, 12a ... Image processing circuit, 13 ... Printing part, 27 ... ADF, 40a ... first image sensor, 40b ... second image sensor, 50 ... original, 60 ... back image, 60a ... main scanning edge, 60b ... main scanning edge, 60c ..Sub-scanning edge, 60d ... sub-scanning edge, 61 ... surface image, 61a ... main scanning edge, 61b ... main scanning edge, 61c ... sub-scanning edge, 61d ... sub-scanning Scanning edge

Claims (4)

A transport section for transporting a document;
A first reading unit that has a first image sensor, reads one side of the document being conveyed by the conveying unit, and generates image data by the first image sensor;
A second image sensor provided downstream of the first image sensor in the conveyance direction of the document; and the other surface of the document conveyed by the conveyance unit is formed by the second image sensor. A second reading unit that reads and generates image data;
A first document inclination detection unit that detects the inclination of the document when being read by the first reading unit;
A second document inclination detecting unit for detecting the inclination of the document when being read by the second reading unit;
A variation determining unit that determines whether or not the inclination of the document has changed during reading of the document by at least one of the reading units;
The variation determination unit determines that the inclination of the document has not changed, and the inclination detected by the first document inclination detection unit and the inclination detected by the second document inclination detection unit are equal. If not, the first image sensor and the second image sensor are determined to be in a first state that is relatively inclined,
The variation determining unit determines that the inclination of the original has not changed, and the inclination detected by the first original inclination detecting unit coincides with the inclination detected by the second original inclination detecting unit. in which, if you are inclined and slope is detected and the first inclination detected by the original Ko傾-out detection unit by the second document skew detection section, while the document is transported inclined A sensor inclination determination unit for determining a second state;
When the sensor inclination determination unit determines that the image is in the first state, the image data is subjected to a first correction process that is a correction process for correcting the inclination of the image data that is not a rectangle and each side is a straight line. And
When the sensor inclination determination unit determines the second state, a second correction process, which is a rotation correction process that corrects the inclination of the image data that is rectangular and each side is a straight line, is performed on the image data. A correction processing unit to be executed
An image reading apparatus comprising: The image reading apparatus according to claim 1,
The fluctuation determining unit determines whether the inclination of the original has changed during reading of the original by the reading unit for both the first reading unit and the second reading unit. . The image reading apparatus according to claim 1 or 2,
When the sensor inclination determination unit determines that the first image sensor and the second image sensor are relatively inclined, the user indicates that the two image sensors are relatively inclined. An image reading apparatus comprising an informing unit for informing the user. An image reading apparatus according to any one of claims 1 to 3,
The variation determining unit determines whether at least one of the reading units has an edge representing a side of the document in the image data generated by the reading unit, and if the edge is a straight line, the reading is performed. An image reading apparatus that determines that the inclination of the original does not change during reading by the scanner, and determines that the inclination of the original changes during reading by the reading section if the original is not a straight line.

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