Sheet conveying device, image processing device, and sheet conveying method

Abstract

To provide a sheet conveying device, an image processing apparatus, and a sheet conveying method that can efficiently read an image of a sheet when an abnormality occurs in a reading unit.SOLUTION: An image forming apparatus 100 comprises: a detection processing unit 52 that detects an abnormality in a first imaging unit 42 that is provided on a first conveyance passage starting from a document placement unit 21 and reaching a first ejection unit 29 through a first conveyance path 22A and reads an image of a document conveyed through the first conveyance passage, and an abnormality in a second imaging unit 43 that is provided on a second conveyance passage reaching a second ejection unit 33 through a second conveyance path 22D including a curved part 22C branching from the upstream side of the first imaging unit 42 on the first conveyance path 22A and curved and reads an image of a document conveyed through the second conveyance passage; and a conveyance control unit 53 that, based on each of results of detection of the abnormalities in the first imaging unit 42 and the second imaging unit 43, sets the conveyance path of the document to one of the first conveyance passage and the second conveyance passage.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a sheet conveying device, an image processing apparatus including the sheet conveying device, and a sheet conveying method. [Background technology]

[0002] There is known an image processing apparatus equipped with a sheet transport device that transports a document to be read. There is also known an image reading apparatus equipped with multiple reading units that read images on both sides (front and back sides) of a document (see Patent Document 1). In the case where one reading unit of the image reading apparatus breaks down, the other reading unit continues the reading process by reading the image of the document. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-343409 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional technology, when scanning both sides of a document, if one scanning unit fails and the other scanning unit scans only one side of the image, the user must place the document on the document loading unit again, and the other scanning unit must scan the document again. This increases the time it takes to read the image. Thus, if an abnormality occurs in one of the multiple scanning units, the efficiency of the document image scanning process decreases.

[0005] An object of the present invention is to provide a sheet conveying device, an image processing device, and a sheet conveying method that are capable of efficiently reading an image on a sheet when an abnormality occurs in the reading unit. [Means for solving the problem]

[0006] According to one aspect of the present invention, a sheet transport device includes a detection processor and a transport controller. The detection processor detects abnormalities in 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 configured to read an image of a 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, and configured to read an image of a sheet transported along the second transport path. 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 abnormalities in the first reading unit and the second reading unit by the detection processor.

[0007] An image processing apparatus according to another aspect of the present invention includes the sheet conveying device and an image reading section, wherein the image reading section reads an image on a sheet conveyed by the sheet conveying device.

[0008] According to another aspect of the present invention, a sheet transport method includes a detecting step and a transport control step. The detecting step detects an abnormality in 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 curves, reading an image of the sheet transported on the second transport path. 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 abnormalities of the first reading unit and the second reading unit in the detecting step. [Effects of the Invention]

[0009] According to the present invention, it is possible to efficiently read an image on a sheet when an abnormality occurs in the reading unit. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing the system configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 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. [Figure 3] 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. [Figure 4] 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. [Figure 5] 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. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the following embodiment is an example of the present invention, and does not limit the technical scope of the present invention.

[0012] [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.

[0013] The image forming apparatus 100 is a multifunction peripheral having multiple functions, such as 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. The image forming apparatus 100 is an example of an image processing apparatus of the present invention. The image processing apparatus of the present invention may also be a scanner, a facsimile machine, a copy machine, or the like.

[0014] As shown in FIG. 1, the image forming apparatus 100 includes an ADF (Auto Document Feeder) 1, an image reading unit 2, an image forming unit 3, a paper feeding unit 4, an operation display unit 5, a storage unit 6, and a control unit .

[0015] The ADF 1 conveys a document (an example of a sheet of the present invention) to be read by the scanning function.

[0016] The image reading unit 2 realizes the scanning function. Specifically, the image reading unit 2 reads an image from a document conveyed by the ADF 1. The image reading unit 2 also reads an image from a document placed on a document table 41 (see FIG. 2).

[0017] 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 by electrophotography. 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.

[0018] 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 a plurality of transport rollers.

[0019] The operation display unit 5 is a user interface of the image forming apparatus 100. For example, the operation display unit 5 has a display unit such as a liquid crystal 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.

[0020] The storage unit 6 is a nonvolatile storage device, such as a nonvolatile memory such as a flash memory or an EEPROM (registered trademark), a solid state drive (SSD), or a hard disk drive (HDD).

[0021] The control unit 7 performs 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 stores in advance 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 that is used as a 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 that are pre-stored in the ROM 12. In this way, the control unit 7 performs overall control of the image forming apparatus 100.

[0022] [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.

[0023] 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 conveying roller 30, a second conveying roller 31, a second discharge roller 32, and a second discharge section 33.

[0024] A document to be transported is placed on document placement section 21. In ADF 1, the document placed on document placement section 21 is transported in transport direction D1 shown in Fig. 2. Document placement section 21 is an example of a sheet placement section of the present invention.

[0025] 1 is provided in the document placement unit 21. 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.

[0026] Further, a lift plate (not shown) is provided on the document placement section 21. The lift plate lifts the document stack placed on the document placement section 21 up to a contact position with the pickup roller 23.

[0027] The housing 22 houses rollers and the like used to transport the document. As shown in FIG. 2, a first transport path 22A and a second transport path 22D for guiding the document are formed inside the housing 22. The first transport path 22A advances straight from the document placement unit 21 to the first discharge unit 29. The second transport path 22D includes a curved portion 22C (see FIG. 2) that branches off from a branching portion 22B (see FIG. 2) in the first transport path 22A and curves, and leads to the second discharge unit 33. The curved portion 22C is curved at a curvature that allows the document to make a U-turn inside the housing 22.

[0028] In ADF1, the document placed on the document placement section 21 is transported along either a first transport path that leads to the first discharge section 29 via the first transport path 22A, or a second transport path that leads to the second discharge section 33 via the second transport path 22D.

[0029] 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 FIGS. 1 and 2) of the image reading unit 2 reads an image of the document transported by the ADF 1.

[0030] The pickup roller 23 is provided above the document placement unit 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.

[0031] The paper feed belt 24 is provided on the first transport path 22A. The paper feed belt 24 comes into contact with the surface of the document transported in the transport direction D1 by the pickup roller 23, and transports the document downstream in the transport direction D1.

[0032] Separation roller 25 is provided below paper feed belt 24 in contact with paper feed belt 24. Of multiple documents transported to the contact position with paper feed belt 24, separation roller 25 separates a document that is in contact with paper feed belt 24 from documents below it.

[0033] The registration rollers 26 are provided on the first transport path 22A downstream in the transport direction D1 from the paper feed belt 24. The registration rollers 26 come into contact with the document transported by the paper feed belt 24 and transport the document downstream in the transport direction D1.

[0034] 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 provided so that its position can be changed between a first position in which the document is guided to the downstream side of the branching portion 22B on the first transport path 22A, and a second position in which the document is guided to the second transport path 22D. The switching unit 27 changes its position by receiving a driving force supplied from the driving unit 27A shown in FIG. 1. For example, the driving unit 27A is a motor.

[0035] The first discharge roller 28 is provided on the first transport path 22A downstream of the branching portion 22B in the transport direction D1. The first discharge roller 28 comes into contact with the document guided by the switching portion 27 to the downstream side of the branching portion 22B on the first transport path 22A, and discharges the document to the first discharge portion 29. The document discharged by the first discharge roller 28 is stacked in the first discharge portion 29.

[0036] The first transport rollers 30 are provided at the curved portion 22C of the second transport path 22D. The first transport rollers 30 come into contact with the document guided to the second transport path 22D by the switching unit 27, and transport the document downstream in the transport direction D1.

[0037] An opening 22E is formed in the second transport path 22D downstream in the transport direction D1 from the first transport roller 30. In the opening 22E, the image of the document passing through the opening 22E is read by the second imaging unit 43 (see FIGS. 1 and 2) of the image reading unit 2.

[0038] The second transport roller 31 is provided on the second transport path 22D downstream of the opening 22E in the transport direction D1. The second transport roller 31 comes into contact with the document transported by the first transport roller 30, and transports the document downstream in the transport direction D1.

[0039] The second discharge roller 32 is provided on the second conveying path 22D downstream of the second conveying roller 31 in the conveying direction D1. The second discharge roller 32 comes into contact with the document conveyed by the second conveying 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.

[0040] 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 a first reading unit of the present invention, the second imaging unit 43 is an example of a second reading unit of the present invention, and the third imaging unit 44 is an example of a third reading unit of the present invention.

[0041] A document to be read is placed on document table 41. Document table 41 is provided on the upper part of the housing of image forming apparatus 100. ADF 1 is provided so as to be openable and closable relative to document table 41, and also serves as a document cover that supports one side of a document placed on first contact glass 411 of document table 41.

[0042] 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 the 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.

[0043] 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 movably in the left-right direction of the paper in FIG. 2. The second imaging unit 43, while disposed below the second contact glass 412, reads an image of the front side of a document (an example of the first side of the present invention) conveyed 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 front side 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.

[0044] The first imaging unit 42 is provided downstream of the branching portion 22B on the first conveying path 22A in the conveying direction D1 and upstream of the first discharge roller 28 in the conveying direction D1. The first imaging unit 42 reads an image of the front surface of the document sheet (an example of the first surface of the present invention) that has been guided downstream of the branching portion 22B on the first conveying 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 sheet. 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.

[0045] The third imaging unit 44 is provided on the first conveying path 22A upstream of the branching portion 22B in the conveying direction D1 and downstream of the registration rollers 26 in the conveying direction D1. The third imaging unit 44 reads an image of the back side (an example of the second side of the present invention) of the document conveyed 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.

[0046] Incidentally, there is known an image reading device that, when one of two reading units that reads images on both sides of a document fails, continues the reading process by reading the image of the document using the other reading unit.

[0047] However, in the above-described image reading device, when reading both sides of a document, if one reading unit fails and the other reading unit reads only one side of the image, the user must place the document on the document loading unit again, and the other reading unit must re-read the document. This increases the time it takes to read the image. Thus, if an abnormality occurs in one of the multiple reading units, the efficiency of the document image reading process decreases.

[0048] In contrast to this, in the image forming apparatus 100 according to the embodiment of the present invention, as will be described below, it is possible to efficiently read the image of the document even if an abnormality occurs in the reading unit.

[0049] [Configuration of control unit 7] Next, the configuration of the control unit 7 will be described in more detail with reference to FIG.

[0050] 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 .

[0051] Specifically, a document reading program for causing the CPU 11 to execute a document reading process (see FIG. 5) described below is stored in advance in the ROM 12. The control unit 7 executes the document reading program stored in the ROM 12, thereby functioning as an acquisition processing unit 51, a detection processing unit 52, a conveyance control unit 53, and a notification processing unit 54. Here, an apparatus including the ADF 1 and the control unit 7 is an example of a sheet conveying apparatus of the present invention.

[0052] The document reading program may be recorded on a computer-readable recording medium such as a CD, a DVD, or a 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, the detection processing unit 52, the transport control unit 53, and the notification processing unit 54 may be configured by electronic circuits such as an integrated circuit (ASIC).

[0053] The acquisition processing unit 51 acquires transport path information indicating whether the transport path of the document placed on the document placing 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 FIG. 2).

[0054] 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 of the original documents on a reception screen displayed on the operation display unit 5. For example, when the user wants to read a stack of original documents including multiple original documents in a short time, the user selects the first discharge unit 29, which corresponds to the first transport path, the transport path length of which is shorter than the second transport path. Also, for example, when 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 placing unit 21, the user selects the second discharge unit 33.

[0055] 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.

[0056] Furthermore, the acquisition processing unit 51 may be omitted from the image forming apparatus 100. In this case, the user places an original on the original placement unit 21 and issues an image reading instruction on the reception screen.

[0057] The detection processing unit 52 detects an abnormality in the image reading unit 2. Specifically, the detection processing unit 52 monitors the states of the first imaging unit 42, the second imaging unit 43, and the third imaging unit 44, and detects an abnormality in each of the imaging units 42, 43, and 44. For example, the detection processing unit 52 performs data communication with each of the imaging units 42, 43, and 44, and detects an abnormality based on the voltage level of a signal output from each of the imaging units 42, 43, and 44. The detection processing unit 52 may also detect an abnormality based on the voltage level of an analog signal corresponding to an image read from a document by each of the imaging units 42, 43, and 44. The method for detecting an abnormality in the imaging unit is not limited to these, and well-known methods can be applied. Note that an abnormality in the imaging unit is not limited to a state in which the imaging unit is inoperable (failure), but also includes a state in which operation is unstable.

[0058] The transport control unit 53 transports the document placed on the document placing 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 including multiple documents is placed on the document placing unit 21, the transport control unit 53 transports each document in the document stack sequentially 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.

[0059] Furthermore, the transport control unit 53 sets either the first transport path or the second transport path based on the detection result of an abnormality in the image reading unit 2 by the detection processing unit 52. For example, the transport control unit 53 sets either the first transport path or the second transport path based on the detection result of an abnormality in the first imaging unit 42 and the second imaging unit 43 by the detection processing unit 52.

[0060] For example, FIG. 3 shows a case where the document transport path is set to the first transport path. The dotted transport path in FIG. 3 corresponds to the first transport path. Here, if the detection processing unit 52 detects an abnormality in 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 FIG. 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 when the image reading unit 2 reads only one side (front side) of the document, i.e., when the document reading mode is set to the single-sided reading mode in advance, the reading process of the third imaging unit 44 is omitted.

[0061] In this way, when the detection processing unit 52 detects an abnormality in the imaging unit provided on the first transport path, the transport control unit 53 sets the transport path to the second transport path. Also, for example, if the detection processing unit 52 detects an abnormality in the imaging unit (e.g., first imaging unit 42) provided on the first transport path while the transport control unit 53 is transporting documents of a document 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 time of detecting the abnormality, and transports the subsequent documents sequentially along the second transport path.

[0062] 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 an abnormality in 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 placement 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 when the image reading unit 2 reads only one side (front side) of the document, i.e., when the document reading mode is set to the single-sided reading mode in advance, the reading process of the third imaging unit 44 is omitted.

[0063] In this way, when the detection processing unit 52 detects an abnormality in the imaging unit provided on the second transport path, the transport control unit 53 sets the transport path to the first transport path. Also, for example, if the detection processing unit 52 detects an abnormality in the imaging unit (e.g., the second imaging unit 43) provided on the second transport path while the transport control unit 53 is transporting documents of a document 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 time of detecting the abnormality, and transports the subsequent documents sequentially along the first transport path.

[0064] 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 an abnormality in the image reading unit 2 detected by the detection processing unit 52. For example, when the detection processing unit 52 detects an abnormality in the image reading unit 2 (the second imaging unit 43, the first imaging unit 42, or the third imaging unit 44), the notification processing unit 54 causes the operation display unit 5 to display a message indicating that an abnormality has occurred in the image reading unit 2, a message urging the user to replace the image reading unit 2 in which the abnormality has occurred, or the like.

[0065] In addition, when an abnormality is detected in the image reading unit 2 and the transport route is switched from the transport route set by the user to another transport route, the notification processing unit 54 displays a message on the operation display unit 5 indicating that the transport route has been switched.

[0066] For example, as shown in FIG. 3, when the detection processing unit 52 detects an abnormality in 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, and the like.

[0067] For example, as shown in FIG. 4, when the detection processing unit 52 detects an abnormality in 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, and the like.

[0068] Here, if the detection processing unit 52 detects an abnormality in 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 an abnormality has occurred in the third imaging unit 44.

[0069] On the other hand, 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 an abnormality in the third imaging unit 44. The notification processing unit 54 then displays a message on the operation display unit 5 indicating that an abnormality has occurred in 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 a selection screen on the operation display unit 5 that prompts the user to select whether 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 discharged document stack on the document stacking 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, and causes the normal imaging unit to perform the process of reading the back side.

[0070] [Document scanning process] 5, an example of the procedure of the document reading process executed by the control unit 7 in the image forming apparatus 100, as well as 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.

[0071] <Step S11> First, in step S11, the control unit 7 determines whether or not the transport route information has been acquired.

[0072] Specifically, the control unit 7 receives an operation from the user to select either the first discharge unit 29 or the second discharge unit 33 as the discharge destination of the document on the reception screen displayed on the operation display unit 5. When 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 when 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 executed by the acquisition processing unit 51 of the control unit 7. The user places the document on the document placement unit 21, selects the discharge destination of the document on the reception screen, etc., and then issues an instruction to read the image.

[0073] <Step S12> In step S12, the control unit 7 sets a transport path.

[0074] Specifically, the control unit 7 sets a transport path for transporting the document placed on the document placing 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.

[0075] 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 attitude of the switching unit 27 to the first attitude that guides the document to the downstream side of the branching unit 22B in 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 attitude of the switching unit 27 to the second attitude 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.

[0076] <Step S13> In step S13, the control unit 7 determines whether an abnormality in the image reading unit 2 has been detected.

[0077] Specifically, when the conveying path is set to the first conveying path in step S12, the control unit 7 determines whether an abnormality has occurred in the first imaging unit 42. Furthermore, when the conveying path is set to the second conveying path in step S12, the control unit 7 determines whether an abnormality has occurred in the second imaging unit 43. Note that when the double-sided reading mode is set, the control unit 7 may also determine whether an abnormality has occurred in the third imaging unit 44. Furthermore, the control unit 7 may execute abnormality detection processing for each of the imaging units 42, 43, and 44, regardless of the set conveying path and reading mode.

[0078] If the control unit 7 detects an abnormality in the image reading unit 2 (S13: Yes), the control unit 7 shifts the process to step S14. On the other hand, if the control unit 7 does not detect an abnormality in the image reading unit 2 (S13: No), the control unit 7 shifts 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.

[0079] In addition, when the control unit 7 detects an abnormality in the image reading unit 2 (S13: Yes), it may display on the operation display unit 5 a message indicating that an abnormality has occurred in the image reading unit 2, a message urging the user to replace the image reading unit 2 in which the abnormality has occurred, or the like.

[0080] <Step S14> In step S14, the control unit 7 switches the transport path set in step S12.

[0081] Specifically, the control unit 7 sets the transport path to the first transport path in step S12, and when an abnormality in the first imaging unit 42 is detected in step S13, the control unit 7 switches the first transport path to the second transport path.

[0082] 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 when an abnormality is detected in the second imaging unit 43 in step S13. The process 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.

[0083] <Step S15> In step S15, the control unit 7 executes an image reading process.

[0084] 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.

[0085] 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 a 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.

[0086] <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 placing unit 21. The control unit 7 determines that the image reading process has not ended when there is a document on the document placing 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.

[0087] 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.

[0088] <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.

[0089] Here, for example, when a stack of documents including a plurality of documents is placed on the document placement unit 21, the control unit 7 repeatedly executes the processes of steps S13 to S16 for each document. Therefore, when the control unit 7 detects an abnormality in the image reading unit 2 between the first document and the last document of the document stack (S13: Yes), the control unit 7 switches to the transport path and continues the image reading process (S15). In this way, the control unit 7 continues to execute the image reading process until the image reading process of the document stack is completed.

[0090] As described above, image forming apparatus 100 detects abnormalities in first imaging unit 42, which is provided on the first transport path from document placement unit 21, on which documents are placed, to first discharge unit 29 via first transport path 22A and reads an image of the document transported on the first transport path, and in second imaging unit 43, which is provided on the second transport path from first transport path 22A to second discharge unit 33, which is different from first discharge unit 29, via second transport path 22D including curved portion 22C that branches off from the upstream side of first imaging unit 42 and curves, and reads an image of the document transported on the second transport path. Furthermore, image forming apparatus 100 sets the transport path of the document to either the first transport path or the second transport path based on the detection results of abnormalities in first imaging unit 42 and second imaging unit 43, respectively.

[0091] This improves the efficiency of the image reading process because even if an abnormality occurs in 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. Also, in the double-sided reading mode, even if an abnormality occurs in either the first imaging unit 42 or the second imaging unit 43, the double-sided reading process can be continued without interruption.

[0092] [Other embodiments] The acquisition processing unit 51 may acquire transport route information according to the type of document (such as "plain paper" or "thick paper"). For example, when the user selects "thick paper" on the reception screen, the acquisition processing unit 51 acquires transport route information indicating that the transport route is the first transport route, and when the user selects "plain paper" on the reception screen, the acquisition processing unit 51 acquires transport route information indicating that the transport route is the second transport route. The transport control unit 53 sets the transport route according to the transport route information.

[0093] In the above configuration, for example, if an abnormality occurs in 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 document (cardboard) through 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.

[0094] Furthermore, the image forming apparatus 100 may 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, when 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 when 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.

[0095] Similarly, in the above configuration, for example, if an abnormality occurs in 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 okay to transport a document 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. [Explanation of symbols]

[0096] 1 ADF 2 Image reading unit 3 Image forming unit 4 Paper feed section 5 Operation display section 6 Memory section 7 Control Unit 21 Document placement area 21A First detection unit 22 Case 22A First conveying path 22B Branch 22C curved section 22D Second transport path 27 Switching section 27A Drive Unit 29 1st discharge section 33 Second discharge section 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 section 100 Image forming device

Claims

1. a detection processing unit that detects abnormalities in 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 that 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 that is different from the first discharge unit and that reads an image of the sheet transported on the second transport path; 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 the abnormality of each of the first reading unit and the second reading unit by the detection processing unit; Equipped with When the detection processing unit detects an abnormality in 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 between the first conveyance path and 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 an abnormality in 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.

2. a notification processing unit configured to notify the detection results of abnormalities in the first reading unit and the second reading unit by the detection processing unit, The sheet transport device according to claim 1 .

3. The notification processing unit displays a message indicating that double-sided reading of the sheet cannot be performed when the detection processing unit detects an abnormality in the third reading unit. The sheet transport device according to claim 2 .

4. a sheet conveying device according to any one of claims 1 to 3; an image reading unit that reads an image on a sheet conveyed by the sheet conveying device; An image processing device comprising:

5. a detection step of detecting an abnormality in each 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 curves, and reading an image of the sheet transported on the second transport path; a transport control step of setting a transport path for a sheet to either the first transport path or the second transport path based on the detection results of the abnormalities of the first reading unit and the second reading unit in the detection step; Including, When an abnormality in 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 respect to the curved portion and that reads an image on a second side of the sheet, A sheet conveying method in which, when an abnormality in the second reading unit is detected 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 the image on the first side of the sheet and the third reading unit reading the image on the second side of the sheet.

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