JP7823364B2 - Sheet conveying device, image processing device, and sheet conveying method - Google Patents

Description

The present invention relates to a sheet conveying device, an image processing device equipped with the sheet conveying device, and a sheet conveying method.

Image processing devices equipped with a sheet transport device that transports a document to be read are known. Image reading devices equipped with a reading unit that reads an image of the document are also known (see Patent Document 1). These image reading devices detect dust adhering to the document reading position of the reading unit, and remove noise caused by the dust from the read image.

Japanese Patent Application Laid-Open No. 2007-142671

However, with conventional technology, when there are many documents to be scanned, the number of scanned images that require noise removal processing increases, resulting in a longer processing time. This results in a problem of reduced efficiency in the scanning process of document images.

The object of the present invention is to provide a sheet conveying device, an image processing device, and a sheet conveying method that can efficiently read a sheet image when noise occurs at the sheet reading position.

A sheet transport device according to one aspect of the present invention includes a detection processor and a transport controller. The detection processor detects noise at the reading positions of a first reading unit provided on a first transport path from a sheet placement unit on which a sheet is placed to a first discharge unit via a first transport path and reads an image of the sheet transported on the first transport path, and a second reading unit provided on a second transport path from the first transport path to a second discharge unit different from the first discharge unit via a second transport path including a curved portion that branches off from the first transport path upstream of the first reading unit and curves, respectively. The transport controller sets the sheet transport path to either the first transport path or the second transport path based on the detection results of the noise at the reading positions of the first reading unit and the second reading unit by the detection processor.

An image processing device according to another aspect of the present invention includes the sheet conveying device and an image reading unit. The image reading unit reads an image on a sheet conveyed by the sheet conveying device.

A sheet transport method according to another aspect of the present invention includes a detection step and a transport control step. The detection step detects noise at the reading positions of a first reading unit provided on a first transport path extending from a sheet placement unit on which a sheet is placed to a first discharge unit via a first transport path and reading an image of the sheet transported along the first transport path, and a second reading unit provided on a second transport path extending from the first transport path upstream of the first reading unit to a second discharge unit different from the first discharge unit via a second transport path including a curved portion that branches off from the first transport path upstream of the first reading unit and curves, respectively. The transport control step sets the sheet transport path to either the first transport path or the second transport path based on the detection results of the noise at the reading positions of the first reading unit and the second reading unit in the detection step.

According to the present invention, it is possible to efficiently read the image on the sheet when noise occurs at the reading position of the sheet.

FIG. 1 is a block diagram showing the system configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing the configuration of the ADF and image reading unit of the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a diagram showing an example of a method for switching the transport path in the image forming apparatus according to the embodiment of the present invention. FIG. 4 is a diagram showing an example of a method for switching the transport path in the image forming apparatus according to the embodiment of the present invention. FIG. 5 is a flowchart showing an example of a document reading process executed by the image forming apparatus according to the embodiment of the present invention.

Embodiments of the present invention will now be described with reference to the accompanying drawings. Note that the following embodiments are merely examples of the present invention and do not limit the technical scope of the present invention.

[Configuration of image forming apparatus 100]
First, with reference to FIG. 1, the configuration of an image forming apparatus 100 according to an embodiment of the present invention will be described.

Image forming device 100 is a multifunction device that has multiple functions, including a scanning function for reading an image from a document, a printing function for forming an image based on image data, a facsimile function, and a copy function. Image forming device 100 is an example of an image processing device of the present invention. Note that the image processing device of the present invention may also be a scanner, a facsimile machine, a copy machine, etc.

As shown in FIG. 1, the image forming device 100 includes an ADF (Auto Document Feeder) 1, an image reading unit 2, an image forming unit 3, a paper feed unit 4, an operation display unit 5, a memory unit 6, and a control unit 7.

ADF1 transports documents (an example of a sheet in the present invention) to be read using the scanning function.

The image reading unit 2 implements the scanning function. Specifically, the image reading unit 2 reads images from documents transported by the ADF 1. The image reading unit 2 also reads images from documents placed on the document table 41 (see Figure 2).

The image forming unit 3 realizes the printing function. For example, the image forming unit 3 forms an image on a sheet supplied from the paper feed unit 4 using an electrophotographic method. For example, the image forming unit 3 includes a photosensitive drum, a charging roller, an optical scanning device, a developing device, a transfer roller, a cleaning device, a fixing device, and a paper output tray.

The paper feed unit 4 supplies sheets to the image forming unit 3. For example, the paper feed unit 4 includes a paper feed cassette, a manual feed tray, a sheet transport path, and multiple transport rollers.

The operation and display unit 5 is a user interface for the image forming apparatus 100. For example, the operation and display unit 5 has a display unit such as an LCD display that displays various information in response to control instructions from the control unit 7, and an operation unit such as operation keys or a touch panel that inputs various information to the control unit 7 in response to user operations.

The storage unit 6 is a non-volatile storage device. For example, the storage unit 6 is a storage device such as a non-volatile memory such as flash memory or EEPROM (registered trademark), an SSD (Solid State Drive), or an HDD (Hard Disk Drive).

The control unit 7 provides overall control of the image forming apparatus 100. As shown in FIG. 1, the control unit 7 includes a CPU 11, a ROM 12, and a RAM 13. The CPU 11 is a processor that executes various types of arithmetic processing. The ROM 12 is a non-volatile storage device that pre-stores information such as control programs for causing the CPU 11 to execute various types of processing. The RAM 13 is a volatile or non-volatile storage device used as temporary storage memory (work area) for the various types of processing executed by the CPU 11. In the control unit 7, the CPU 11 executes the various control programs pre-stored in the ROM 12. In this way, the control unit 7 provides overall control of the image forming apparatus 100.

[Configuration of ADF 1 and image reading unit 2]
Next, the configurations of the ADF 1 and the image reading unit 2 will be described with reference to Figures 1 and 2. Figure 2 is a cross-sectional view showing the configurations of the ADF 1 and the image reading unit 2.

As shown in FIG. 2, the ADF 1 includes a document placement section 21, a housing 22, a pickup roller 23, a paper feed belt 24, a separation roller 25, a registration roller 26, a switching section 27, a first discharge roller 28, a first discharge section 29, a first transport roller 30, a second transport roller 31, a second discharge roller 32, and a second discharge section 33.

The document to be transported is placed on the document placement section 21. In the ADF 1, the document placed on the document placement section 21 is transported in the transport direction D1 shown in Figure 2. The document placement section 21 is an example of a sheet placement section of the present invention.

The document placement unit 21 is provided with a first detection unit 21A, as shown in FIG. 1. The first detection unit 21A detects whether or not a document is present on the document placement unit 21. For example, the first detection unit 21A is a reflective optical sensor provided on the document placement surface of the document placement unit 21.

The document placement section 21 is also provided with a lift plate (not shown). The lift plate lifts the stack of documents placed on the document placement section 21 up to a contact position with the pickup roller 23.

The housing 22 houses rollers and other components used to transport the document. As shown in FIG. 2, a first transport path 22A and a second transport path 22D are formed inside the housing 22 to guide the document. The first transport path 22A travels straight from the document placement section 21 to the first discharge section 29. The second transport path 22D includes a curved section 22C (see FIG. 2) that branches off from a branching section 22B (see FIG. 2) in the first transport path 22A and curves, leading to the second discharge section 33. The curved section 22C is curved at a curvature that allows the document to make a U-turn inside the housing 22.

In ADF1, documents placed on the document placement section 21 are transported along either the first transport path, which leads to the first discharge section 29 via the first transport path 22A, or the second transport path, which leads to the second discharge section 33 via the second transport path 22D.

As shown in Figure 2, an opening 22E is provided at the bottom of the housing 22. The opening 22E exposes a portion of the second transport path 22D to the outside. In the opening 22E, the second imaging unit 43 (see Figures 1 and 2) of the image reading unit 2 reads the image of the document being transported by the ADF 1.

The pickup roller 23 is provided above the document placement section 21. The pickup roller 23 comes into contact with the surface (top surface) of the uppermost document in the document stack lifted by the lift plate, and transports the document in the transport direction D1.

The paper feed belt 24 is provided in the first transport path 22A. The paper feed belt 24 comes into contact with the surface of the document being transported in the transport direction D1 by the pickup roller 23, and transports the document downstream in the transport direction D1.

The separation roller 25 is provided below the paper feed belt 24 and in contact with the paper feed belt 24. Of the multiple documents transported to the contact position with the paper feed belt 24, the separation roller 25 separates the document that is in contact with the paper feed belt 24 from the document below it.

The registration rollers 26 are provided downstream of the paper feed belt 24 in the first transport path 22A in the transport direction D1. The registration rollers 26 come into contact with the document being transported by the paper feed belt 24 and transport the document downstream in the transport direction D1.

The switching unit 27 is provided at the branching portion 22B on the first transport path 22A, downstream of the registration rollers 26 in the transport direction D1. The switching unit 27 is a guide member that comes into contact with the document transported by the registration rollers 26 and guides the document to either the downstream side of the branching portion 22B on the first transport path 22A or the second transport path 22D. Specifically, the switching unit 27 is capable of changing its position between a first position that guides the document downstream of the branching portion 22B on the first transport path 22A, and a second position that guides the document to the second transport path 22D. The switching unit 27 changes its position in response to a driving force supplied by the driving unit 27A shown in FIG. 1. For example, the driving unit 27A is a motor.

The first discharge roller 28 is provided downstream of the branching portion 22B on the first transport path 22A in the transport direction D1. The first discharge roller 28 comes into contact with the document guided downstream of the branching portion 22B on the first transport path 22A by the switching portion 27, and discharges the document to the first discharge section 29. The first discharge section 29 is loaded with the document discharged by the first discharge roller 28.

The first transport roller 30 is provided at the curved portion 22C of the second transport path 22D. The first transport roller 30 comes into contact with the document guided into the second transport path 22D by the switching unit 27, and transports the document downstream in the transport direction D1.

An opening 22E is formed in the second transport path 22D downstream of the first transport roller 30 in the transport direction D1. In the opening 22E, the image of the document passing through the opening 22E is read by the second imaging unit 43 (see Figures 1 and 2) of the image reading unit 2.

The second transport roller 31 is located downstream of the opening 22E in the second transport path 22D in the transport direction D1. The second transport roller 31 comes into contact with the document being transported by the first transport roller 30 and transports the document downstream in the transport direction D1.

The second discharge roller 32 is provided downstream of the second transport roller 31 in the transport direction D1 in the second transport path 22D. The second discharge roller 32 comes into contact with the document being transported by the second transport roller 31 and discharges the document to the second discharge section 33. The document discharged by the second discharge roller 32 is stacked in the second discharge section 33.

As shown in Figures 1 and 2, the image reading unit 2 includes a document table 41, a first imaging unit 42, a second imaging unit 43, and a third imaging unit 44. The first imaging unit 42 is an example of the first reading unit of the present invention, the second imaging unit 43 is an example of the second reading unit of the present invention, and the third imaging unit 44 is an example of the third reading unit of the present invention.

The document to be read is placed on the document table 41. The document table 41 is provided at the top of the housing of the image forming apparatus 100. The ADF 1 is provided so that it can be opened and closed relative to the document table 41, and also serves as a document cover that supports one side of the document placed on the first contact glass 411 of the document table 41.

As shown in FIG. 2, the document table 41 includes a first contact glass 411, a second contact glass 412, and a guide member 413. A document whose image is to be read by the second imaging unit 43 is placed on the first contact glass 411. The second contact glass 412 and guide member 413 face the opening 22E of the housing 22 and form part of the second transport path 22D when the ADF 1 is closed relative to the document table 41. The second contact glass 412 transmits light emitted from the second imaging unit 43 toward the opening 22E and light reflected by the document. The guide member 413 guides the document to the second transport roller 31 downstream of the second contact glass 412 in the transport direction D1.

The second imaging unit 43 is provided below the first contact glass 411 and the second contact glass 412. The second imaging unit 43 is elongated in the depth direction of the paper in FIG. 2 and is provided so as to be movable left to right in the paper in FIG. 2. The second imaging unit 43, while positioned below the second contact glass 412, reads an image of the surface of a document (an example of the first surface of the present invention) transported by the ADF 1. Specifically, the second imaging unit 43 includes a CIS (Contact Image Sensor) and a housing that houses the CIS. The second imaging unit 43 outputs an analog signal corresponding to the image read from the surface of the document. The analog signal output from the second imaging unit 43 is converted into a digital signal (image data) by an analog front-end circuit (not shown) and input to the control unit 7.

The first imaging unit 42 is provided downstream of the branching portion 22B on the first transport path 22A in the transport direction D1 and upstream of the first discharge roller 28 in the transport direction D1. The first imaging unit 42 reads an image of the front surface of the document (an example of the first side of the present invention) that has been guided downstream of the branching portion 22B on the first transport path 22A by the switching unit 27. Specifically, the first imaging unit 42 is a CIS. The first imaging unit 42 outputs an analog signal corresponding to the image read from the front surface of the document. The analog signal output from the first imaging unit 42 is converted into a digital signal (image data) by the analog front-end circuit and input to the control unit 7.

The third imaging unit 44 is provided on the first transport path 22A upstream of the branching portion 22B in the transport direction D1 and downstream of the registration rollers 26 in the transport direction D1. The third imaging unit 44 reads an image of the back side of the document (an example of the second side of the present invention) being transported by the registration rollers 26. Specifically, the third imaging unit 44 is a CIS. The third imaging unit 44 outputs an analog signal corresponding to the image read from the back side of the document. The analog signal output from the third imaging unit 44 is converted into a digital signal (image data) by the analog front-end circuit and input to the control unit 7.

By the way, there are known image reading devices that detect dust attached to the document reading position by the reading unit and remove noise caused by the dust from the read image.

However, with the image reading device described above, if there are many documents to be read, the number of scanned images that require noise removal processing increases, resulting in a longer processing time. This creates a problem of reduced efficiency in the document image reading process.

In contrast, the image forming apparatus 100 according to an embodiment of the present invention is capable of efficiently reading an image on a document even when noise occurs at the document reading position, as described below.

[Configuration of control unit 7]
Next, the configuration of the control unit 7 will be described in more detail with reference to FIG.

As shown in FIG. 1, the control unit 7 includes an acquisition processing unit 51, a detection processing unit 52, a transport control unit 53, and a notification processing unit 54.

Specifically, a document reading program for causing the CPU 11 to execute the document reading process (see FIG. 5) described below is stored in advance in the ROM 12. The control unit 7 then executes the document reading program stored in the ROM 12, thereby functioning as an acquisition processing unit 51, a detection processing unit 52, a transport control unit 53, and a notification processing unit 54. Here, an apparatus equipped with the ADF 1 and the control unit 7 is an example of a sheet transport device of the present invention.

The document reading program may be recorded on a computer-readable recording medium such as a CD, DVD, or flash memory, and may be read from the recording medium and stored in a storage device such as the memory unit 6. The acquisition processing unit 51, detection processing unit 52, transport control unit 53, and notification processing unit 54 may also be configured as electronic circuits such as an integrated circuit (ASIC).

The acquisition processing unit 51 acquires transport path information indicating whether the transport path of the document placed on the document placement unit 21 is the first transport path or the second transport path. As described above, the first transport path is the transport path that leads to the first discharge unit 29 via the first transport path 22A, and the second transport path is the transport path that leads to the second discharge unit 33 via the second transport path 22D (see Figure 2).

For example, the control unit 7 accepts an operation from the user to select either the first discharge unit 29 or the second discharge unit 33 as the discharge destination for the original documents on the reception screen displayed on the operation display unit 5. For example, if the user wants to read a stack of original documents containing multiple original documents in a short amount of time, the user selects the first discharge unit 29, which corresponds to the first transport path, whose transport path length is shorter than the second transport path. Also, for example, the user selects the second discharge unit 33 if the user wants the page order of the discharged stack of original documents to match the page order of the stack of original documents placed on the document placement unit 21.

When the user selects the first discharge unit 29, the acquisition processing unit 51 acquires transport path information indicating that the transport path is the first transport path, and when the user selects the second discharge unit 33, the acquisition processing unit 51 acquires transport path information indicating that the transport path is the second transport path. Note that the user may select either the first transport path or the second transport path as the transport path on the reception screen. The user places the document on the document placement unit 21, selects the document discharge destination, etc. on the reception screen, and then issues an instruction to read the image.

The image forming device 100 may also omit the acquisition processing unit 51. In this case, the user places a document on the document placement unit 21 and issues an image reading instruction on the reception screen.

The detection processing unit 52 detects noise at the reading position of the image reading unit 2. The noise is, for example, a noise image that is mixed into the read image due to dust adhering to the reading position. Specifically, the detection processing unit 52 monitors the status of the first imaging unit 42, the second imaging unit 43, and the third imaging unit 44, and detects noise at the reading position of each imaging unit 42, 43, and 44. For example, the detection processing unit 52 performs data communication with each imaging unit 42, 43, and 44, and detects noise at the reading position based on the voltage level of the signal output from each imaging unit 42, 43, and 44. The detection processing unit 52 may also detect noise at the reading position based on the voltage level of an analog signal corresponding to the image read from the original by each imaging unit 42, 43, and 44. The detection processing unit 52 may also detect noise at the reading position by analyzing the image read from the original by each imaging unit 42, 43, and 44 and comparing the pixel values of the image. Methods for detecting noise at the reading position of the imaging unit are not limited to these, and any well-known method can be applied.

The transport control unit 53 transports the document placed on the document placement unit 21 along either the first transport path or the second transport path in accordance with the transport path information acquired by the acquisition processing unit 51. When a document stack containing multiple documents is placed on the document placement unit 21, the transport control unit 53 sequentially transports each document in the document stack along either the first transport path or the second transport path. In this way, the transport control unit 53 sets the transport path to either the first transport path or the second transport path in accordance with the transport path information acquired by the acquisition processing unit 51.

The transport control unit 53 also sets either the first transport path or the second transport path based on the results of noise detection by the detection processing unit 52 at the reading position of the image reading unit 2. For example, the transport control unit 53 sets either the first transport path or the second transport path based on the results of noise detection by the detection processing unit 52 at the reading positions of the first imaging unit 42 and the second imaging unit 43.

For example, Figure 3 shows a case where the document transport path is set to the first transport path. The dotted transport path in Figure 3 corresponds to the first transport path. Here, if the detection processing unit 52 detects noise at the reading position of the first imaging unit 42, the transport control unit 53 switches the transport path from the first transport path to the second transport path. The solid transport path in Figure 3 corresponds to the second transport path. In this case, the document placed on the document loading unit 21 is guided by the branching unit 22B to the curved portion 22C and discharged to the second discharge unit 33 via the second transport path 22D. Also, while the document is transported along the second transport path, the third imaging unit 44 reads an image of the back side of the document, and the second imaging unit 43 reads an image of the front side of the document. Note that if the image reading unit 2 reads only one side (front side) of the document, i.e., if the document reading mode is set to single-sided reading mode in advance, the reading process by the third imaging unit 44 is omitted.

In this way, when the detection processing unit 52 detects noise at the reading position of an imaging unit provided on the first transport path, the transport control unit 53 sets the transport path to the second transport path. Furthermore, for example, if the detection processing unit 52 detects noise at the reading position of an imaging unit (e.g., first imaging unit 42) provided on the first transport path while the transport control unit 53 is transporting documents in a stack sequentially along the first transport path, the transport control unit 53 switches the transport path from the first transport path to the second transport path at the point in time when it detects the noise at the reading position, and transports subsequent documents sequentially along the second transport path.

In contrast, FIG. 4 shows a case where the document transport path is set to the second transport path. The dotted transport path in FIG. 4 corresponds to the second transport path. Here, if the detection processing unit 52 detects noise at the reading position of the second imaging unit 43, the transport control unit 53 switches the transport path from the second transport path to the first transport path. The solid transport path in FIG. 4 corresponds to the first transport path. In this case, the document placed on the document loading unit 21 is discharged to the first discharge unit 29 via the first transport path 22A. Also, while the document is transported along the first transport path, the third imaging unit 44 reads an image of the back side of the document, and the first imaging unit 42 reads an image of the front side of the document. Note that if the image reading unit 2 reads only one side (front side) of the document, i.e., if the document reading mode is set to single-sided reading mode in advance, the reading process by the third imaging unit 44 is omitted.

In this way, when the detection processing unit 52 detects noise at the reading position of an imaging unit provided on the second transport path, the transport control unit 53 sets the transport path to the first transport path. Furthermore, for example, if the detection processing unit 52 detects noise at the reading position of an imaging unit (e.g., second imaging unit 43) provided on the second transport path while the transport control unit 53 is transporting documents in a stack sequentially along the second transport path, the transport control unit 53 switches the transport path from the second transport path to the first transport path at the point in time when it detects the noise at the reading position, and transports subsequent documents sequentially along the first transport path.

The notification processing unit 54 notifies the user of various types of information. Specifically, the notification processing unit 54 notifies the user of the detection result of noise at the reading position of the image reading unit 2 by the detection processing unit 52. For example, when the detection processing unit 52 detects noise at the reading position of the image reading unit 2 (second imaging unit 43, first imaging unit 42, third imaging unit 44), the notification processing unit 54 displays on the operation display unit 5 a message indicating that noise at the image reading unit 2 has been detected, a message urging the user to clean the reading position of the image reading unit 2, etc.

In addition, when noise is detected at the reading position of the image reading unit 2 and the transport path is switched from the transport path set by the user to another transport path, the notification processing unit 54 displays a message on the operation display unit 5 indicating that the transport path has been switched.

For example, as shown in FIG. 3, when the detection processing unit 52 detects noise at the reading position of the first imaging unit 42 and the transport control unit 53 switches the transport path from the first transport path to the second transport path, the notification processing unit 54 displays on the operation display unit 5 a message indicating that the transport path has been switched from the first transport path to the second transport path, a message indicating that the document will be discharged to the second discharge unit 33, etc.

For example, as shown in FIG. 4, when the detection processing unit 52 detects noise at the reading position of the second imaging unit 43 and the transport control unit 53 switches the transport path from the second transport path to the first transport path, the notification processing unit 54 displays on the operation display unit 5 a message indicating that the transport path has been switched from the second transport path to the first transport path, a message indicating that the document will be discharged to the first discharge unit 29, etc.

In addition, when the detection processing unit 52 detects noise at the reading position of the image reading unit 2, the reading process may already have been completed and an image containing noise may exist. In this case, the notification processing unit 54 may display a message on the operation display unit 5 inquiring whether or not to perform re-reading of the document that has already been read at the reading position where noise was detected. When the user confirms the message, they can select whether or not to perform re-reading of the document that has already been read.

Furthermore, when the detection processing unit 52 detects noise at the reading position of the image reading unit 2, the notification processing unit 54 may display a message on the operation display unit 5 inquiring whether to switch the transport path and continue the reading process. In this case, the transport control unit 53 switches the transport path if the user selects to continue the reading process in response to the message. As a result, if the noise is not noticeable to the user, the reading process can be continued without switching the transport path.

Here, if the detection processing unit 52 detects noise at the reading position of the third imaging unit 44, the following processing may be executed. For example, when the image reading unit 2 reads only one side (front side) of the document (single-sided reading mode), the transport control unit 53 continues the transport process using the transport path set by the user without switching the transport path. In addition, the notification processing unit 54 displays a message on the operation display unit 5 indicating that noise has been detected at the reading position of the third imaging unit 44.

In contrast, when the image reading unit 2 reads both sides (front and back) of a document (double-sided reading mode), the transport control unit 53 suspends the document transport process without switching the transport path when the detection processing unit 52 detects noise at the reading position of the third imaging unit 44. The notification processing unit 54 then displays on the operation display unit 5 a message indicating that noise has been detected at the reading position of the third imaging unit 44, a message indicating that the back side of the document cannot be read, or the like. The notification processing unit 54 also displays on the operation display unit 5 a selection screen that allows the user to select whether or not to continue the process of reading only the front side of the document. When the user instructs the user to continue the reading process on the selection screen, the transport control unit 53 resumes the transport process using the transport path set by the user. In this case, for example, the user places the ejected document stack on the document loading unit 21 again, and the transport control unit 53 sequentially transports the documents in the document stack using the transport path set by the user, causing the normal imaging unit to perform the back side reading process.

[Document reading process]
5, an example of the procedure of the document reading process executed by the control unit 7 in the image forming apparatus 100 and the sheet conveying method of the present invention will be described. Here, steps S11, S12, etc. represent the numbers of the processing procedures (steps) executed by the control unit 7. The document reading process is executed when an image reading instruction (e.g., a scan instruction) is given on the operation display unit 5.

<Step S11>
First, in step S11, the control unit 7 determines whether or not the transport route information has been acquired.

Specifically, the control unit 7 accepts an operation from the user to select either the first discharge unit 29 or the second discharge unit 33 as the document discharge destination on the reception screen displayed on the operation display unit 5. If the user selects the first discharge unit 29, the control unit 7 acquires transport path information indicating the first transport path as the transport path, and if the user selects the second discharge unit 33, the control unit 7 acquires transport path information indicating the second transport path as the transport path. The processing of step S11 is performed by the acquisition processing unit 51 of the control unit 7. The user places the document on the document placement unit 21, selects the document discharge destination, etc. on the reception screen, and then issues an instruction to read the image.

<Step S12>
In step S12, the control unit 7 sets a transport path.

Specifically, the control unit 7 sets a transport path for transporting the document placed on the document placement unit 21 in accordance with the transport path information acquired in step S11. For example, when the control unit 7 acquires transport path information indicating the first transport path, it sets the transport path to the first transport path, and when the control unit 7 acquires transport path information indicating the second transport path, it sets the transport path to the second transport path.

For example, when the control unit 7 acquires transport path information indicating the first transport path, it drives the drive unit 27A to set the orientation of the switching unit 27 to the first orientation that guides the document downstream of the branching unit 22B on the first transport path 22A. Furthermore, when the control unit 7 acquires transport path information indicating the second transport path, it drives the drive unit 27A to set the orientation of the switching unit 27 to the second orientation that guides the document to the second transport path 22D. The process of step S12 is executed by the transport control unit 53 of the control unit 7.

<Step S13>
In step S13, the control unit 7 determines whether noise has been detected at the reading position of the image reading unit 2.

Specifically, when the transport path is set to the first transport path in step S12, the control unit 7 determines whether noise at the reading position is detected by the first imaging unit 42. Furthermore, when the transport path is set to the second transport path in step S12, the control unit 7 determines whether noise at the reading position is detected by the second imaging unit 43. Note that when the double-sided reading mode is set, the control unit 7 may also determine whether noise at the reading position is detected by the third imaging unit 44. Furthermore, the control unit 7 may perform processing to detect noise at the reading position for each imaging unit 42, 43, and 44, regardless of the set transport path and reading mode.

If the control unit 7 detects noise at the reading position of the image reading unit 2 (S13: Yes), it transitions the process to step S14. On the other hand, if the control unit 7 does not detect noise at the reading position of the image reading unit 2 (S13: No), it transitions the process to step S15. The process of step S13 is an example of a detection step of the present invention, and is executed by the detection processing unit 52 of the control unit 7.

Furthermore, if the control unit 7 detects noise at the reading position of the image reading unit 2 (S13: Yes), it may cause the image reading unit 2 to display on the operation display unit 5 a message indicating that noise has been detected at the reading position, a message urging the user to clean the reading position, or the like.

<Step S14>
In step S14, the control unit 7 switches the transport path set in step S12.

Specifically, the control unit 7 sets the transport path to the first transport path in step S12, and switches the first transport path to the second transport path when noise is detected at the reading position of the first imaging unit 42 in step S13.

Furthermore, the control unit 7 sets the transport path to the second transport path in step S12, and switches the second transport path to the first transport path if noise is detected at the reading position of the second imaging unit 43 in step S13. The processing of step S14 is an example of a transport control step of the present invention, and is executed by the transport control unit 53 of the control unit 7.

<Step S15>
In step S15, the control unit 7 executes an image reading process.

Specifically, the control unit 7 transports one of the documents placed on the document placement unit 21 along the set transport path. For example, the control unit 7 drives a motor (not shown) to rotate a roller inside the housing 22.

The control unit 7 also reads an image of the document being transported. Specifically, when the transport path is set to the first transport path, the control unit 7 reads an image of the front side of the document using the first imaging unit 42. When the transport path is set to the second transport path, the control unit 7 reads an image of the front side of the document using the second imaging unit 43. Note that when the document reading mode is set to the double-sided reading mode in advance, the control unit 7 reads an image of the back side of the document using the third imaging unit 44 for both the first transport path and the second transport path.

<Step S16>
In step S16, the control unit 7 determines whether the image reading process has ended. For example, the control unit 7 determines that the image reading process has ended when there is no document on the document placement unit 21. The control unit 7 determines that the image reading process has not ended when there is a document on the document placement unit 21. When the image reading process has ended (S16: Yes), the control unit 7 shifts the process to step S17. When the image reading process has not ended (S16: No), the control unit 7 shifts the process to step S13.

In addition, the control unit 7 may determine that the image reading process has ended when the user performs an operation to end the image reading process.

<Step S17>
In step S17, the control unit 7 outputs the image data read by the image reading process to the output destination set by the user.

Here, for example, if a stack of documents containing multiple documents is placed on the document placement unit 21, the control unit 7 repeatedly executes steps S13 to S16 for each document. Therefore, if the control unit 7 detects noise at the reading position of the image reading unit 2 between the first and last documents in the document stack (S13: Yes), it switches to the transport path and continues the image reading process (S15). In this way, the control unit 7 continues executing the image reading process until the image reading process for the document stack is completed.

As described above, the image forming apparatus 100 detects noise at the reading positions of the first imaging unit 42, which is provided on the first transport path from the document loading unit 21 on which the document is placed to the first discharge unit 29 via the first transport path 22A and reads an image of the document transported on the first transport path, and the second imaging unit 43, which is provided on the second transport path from the first transport path 22A to the second discharge unit 33, which is different from the first discharge unit 29, via the second transport path 22D, which includes the curved portion 22C that branches off from the upstream side of the first imaging unit 42 on the first transport path 22A and curves, and reads an image of the document transported on the second transport path. Furthermore, the image forming apparatus 100 sets the document transport path to either the first transport path or the second transport path based on the noise detection results of the first imaging unit 42 and the second imaging unit 43 at their respective reading positions.

As a result, even if noise occurs at the reading position of either the first imaging unit 42 or the second imaging unit 43, the document reading process can be continued by switching to the transport path, thereby improving the efficiency of the image reading process. Furthermore, in double-sided reading mode, even if noise occurs at the reading position of either the first imaging unit 42 or the second imaging unit 43, the double-sided reading process can be continued without interruption.

Other Embodiments
The acquisition processing unit 51 may acquire transport path information according to the type of document (such as "plain paper" or "thick paper"). For example, if the user selects "thick paper" on the reception screen, the acquisition processing unit 51 acquires transport path information indicating that the transport path is the first transport path, and if the user selects "plain paper" on the reception screen, the acquisition processing unit 51 acquires transport path information indicating that the transport path is the second transport path. The transport control unit 53 sets the transport path according to the transport path information.

In the above configuration, for example, if the detection processing unit 52 detects noise at the reading position of the first imaging unit 42, the notification processing unit 54 may inquire of the user on the operation display unit 5 as to whether it is okay to transport the original (cardboard) via the second transport path. If the user agrees, the transport control unit 53 switches the transport path from the first transport path to the second transport path.

The image forming apparatus 100 may also include a sensor that detects the thickness of a document passing through a detection position P1 (see FIG. 2) on the document placement unit 21 side of the branching portion 22B in the first transport path 22A. For example, the sensor may be a transmissive optical sensor or an ultrasonic sensor provided at the detection position P1. The acquisition processing unit 51 may acquire transport path information according to the thickness of the document detected by the sensor. For example, if the thickness of the document detected by the sensor exceeds a threshold, the acquisition processing unit 51 acquires transport path information indicating that the transport path is the first transport path, and if the thickness of the document detected by the sensor is equal to or less than the threshold, the acquisition processing unit 51 acquires transport path information indicating that the transport path is the second transport path. The transport control unit 53 sets the transport path according to the transport path information.

Similarly, in the above configuration, for example, if the detection processing unit 52 detects noise at the reading position of the first imaging unit 42, the notification processing unit 54 may inquire of the user on the operation display unit 5 as to whether or not it is acceptable to transport documents whose thickness exceeds the threshold value via the second transport path. If the user agrees, the transport control unit 53 switches the transport path from the first transport path to the second transport path.

1 ADF
2 Image reading unit 3 Image forming unit 4 Paper feeding unit 5 Operation display unit 6 Memory unit 7 Control unit 21 Document placing unit 21A First detection unit 22 Housing 22A First transport path 22B Branching unit 22C Curved portion 22D Second transport path 27 Switching unit 27A Driving unit 29 First discharge unit 33 Second discharge unit 42 First imaging unit 43 Second imaging unit 44 Third imaging unit 51 Acquisition processing unit 52 Detection processing unit 53 Transport control unit 54 Notification processing unit 100 Image forming apparatus

Claims (7)

a detection processing unit that detects noise at respective reading positions of a first reading unit that is provided on a first transport path from a sheet placement unit on which a sheet is placed to a first discharge unit via a first transport path and reads an image of the sheet transported on the first transport path, and a second reading unit that is provided on a second transport path that is provided on a second transport path that branches off from an upstream side of the first reading unit on the first transport path and includes a curved portion that curves and reads an image of the sheet transported on the second transport path, and
a conveyance control unit that sets a sheet conveyance path to either the first conveyance path or the second conveyance path based on a detection result of noise at each reading position of the first reading unit and the second reading unit by the detection processing unit;
Equipped with
When the detection processing unit detects noise at the reading position of the first reading unit, the conveyance control unit sets the sheet conveyance path to the second conveyance path, and performs double-sided reading of the sheet by the second reading unit that reads an image on a first side of the sheet, and a third reading unit that is provided upstream of a branch point of the first conveyance path with respect to the curved portion and that reads an image on a second side of the sheet,
A sheet conveying device in which, when the detection processing unit detects noise at the reading position of the second reading unit, the conveying control unit sets the sheet conveying path to the first conveying path and performs double-sided reading of the sheet using the first reading unit, which reads an image on the first side of the sheet, and the third reading unit, which reads an image on the second side of the sheet . a notification processing unit configured to notify a result of the detection of noise at the reading positions of the first reading unit and the second reading unit by the detection processing unit,
The sheet transport device according to claim 1 . the notification processing unit displays a message urging cleaning of the reading position where noise is detected;
The sheet transport device according to claim 2 . the notification processing unit displays a message inquiring whether or not to execute the reading process again for the sheet that has already been read at the reading position where the noise is detected;
The sheet transport device according to claim 2 . the notification processing unit displays a message indicating that double-sided reading of the sheet cannot be performed when the detection processing unit detects noise at the reading position of the third reading unit.
The sheet transport device according to claim 2 . A sheet conveying device according to any one of claims 1 to 5 ;
an image reading unit that reads an image on a sheet conveyed by the sheet conveying device;
An image processing device comprising: a detection step of detecting noise at a reading position of a first reading unit provided on a first transport path from a sheet placement unit on which a sheet is placed to a first discharge unit via a first transport path, and reading an image of the sheet transported on the first transport path; and a second reading unit provided on a second transport path from the first transport path to a second discharge unit different from the first discharge unit via a second transport path including a curved portion that branches off from an upstream side of the first reading unit on the first transport path, and reading an image of the sheet transported on the second transport path;
a transport control step of setting a transport path of the sheet to either the first transport path or the second transport path based on the detection results of noise at the respective reading positions of the first reading unit and the second reading unit in the detection step;
Including,
When noise at the reading position of the first reading unit is detected in the detecting step, in the conveyance control step, a sheet conveyance path is set to the second conveyance path, and double-sided reading of the sheet is performed by the second reading unit that reads an image on a first side of the sheet, and a third reading unit that is provided upstream of a branch point of the first conveyance path with the curved portion and that reads an image on a second side of the sheet,
A sheet conveying method in which, when noise is detected at the reading position of the second reading unit in the detection step, the sheet conveying path is set to the first conveying path in the conveying control step, and double-sided reading of the sheet is performed by the first reading unit reading an image on the first side of the sheet and the third reading unit reading an image on the second side of the sheet .