Document reading device and image forming apparatus

Abstract

To prevent jamming of a document when conveying the document by using a horizontal conveyance path.SOLUTION: A document reading device 5 comprises a document placing tray 24, first ejection tray 25, a first conveyance path F1, a first reading unit 40, a conveying unit 28, an operation unit 16, a distance measuring sensor 29, and a control unit 10. When the control unit 10 determines that the first ejection tray 25 is in one of a closed state and a full state on the basis of a result of detection performed by the distance measuring sensor 29 when a document reading instruction from a first reading unit 40 is input to the operation unit 16, the control unit does not cause the conveying unit 28 to convey a document MS and does not cause the first reading unit 40 to read an image. When the control unit determines that the ejection tray is not in the closed state or the full state, the control unit causes the conveying unit 28 to convey the document MS and causes the first reading unit 40 to read an image.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an original reading device and an image forming apparatus, and more particularly to a technique for controlling the transport of an original according to the state of an ejection tray. [Background technology]

[0002] In a document reading device equipped with an automatic document feeder (ADF), a technique for switching a transport path depending on the type of document is known. For example, Patent Document 1 discloses a technique in which, when a normal document is fed, the document is discharged using a curved transport path, and, when a small-sized hard document such as a business card or a driver's license is fed, the document is discharged using an uncurved horizontal transport path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-86988 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, documents to be transported using the horizontal transport path are often important documents such as business cards or driver's licenses. If a document jam occurs in the transport path while such documents are being transported, the important documents may be damaged. The technology disclosed in Patent Document 1 cannot solve such a problem.

[0005] SUMMARY OF THE PRESENT DISCLOSURE The present invention has been made in consideration of the above circumstances, and has an object to prevent document jamming that occurs when documents are transported along a horizontal transport path. [Means for solving the problem]

[0006] A document reading device according to one aspect of the present invention comprises a document loading tray on which a document is placed, a first discharge tray which is closed or open by rotating about a predetermined first rotation axis, a first transport path which extends from the document loading tray to the first discharge tray without curving, a first reading unit provided in the first transport path and which reads an image on one side of the document, a transport unit which transports the document from the document loading tray to the first discharge tray through the first transport path, an input unit to which user instructions are input, a first detection unit which detects the state of the first discharge tray, and a control unit which, when an instruction to read a document by the first reading unit is input to the input unit and the first detection unit detects either a closed state or a full state of the first discharge tray, does not cause the transport unit to transport the document and the first reading unit to read the image, and which, when the first detection unit does not detect either a closed state or a full state, causes the transport unit to transport the document and the first reading unit to read the image.

[0007] An image forming apparatus according to another aspect of the present invention includes the document reading device described above, and an image forming section that forms an image read by the document reading device on a recording medium. Effect of the Invention

[0008] According to the present invention, when the first discharge tray is either closed or full, i.e., when there is a high possibility that document jamming will occur due to document transport, document transport is not performed, thereby preventing document jamming in the first transport path. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a front cross-sectional view showing the structure of the image forming apparatus. [Diagram 2] 1 is a block diagram showing a configuration of an image forming apparatus; [Figure 3A] 4 is a cross-sectional view showing the document transport unit and the image reading unit when the paper feed cover and the first discharge tray are in a closed state. FIG. [Figure 3B] 4 is a cross-sectional view showing the document transport unit and the image reading unit when the first discharge tray is in an open state. FIG. [Figure 4A] 11 is a side view showing the document transport section when the first discharge tray is in a closed state. FIG. [Figure 4B] 11 is a side view showing the document transport section when the first discharge tray is in an open state. FIG. [Diagram 5] 13 is a flowchart showing a horizontal conveying process. [Figure 6] 13A and 13B are diagrams showing a state in which documents fall from a first discharge tray as the paper feed cover rotates. [Figure 7] FIG. 11 is a diagram illustrating another example of the first detection unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a document reading device and an image forming device according to an embodiment of the present invention will be described with reference to the drawings.

[0011] [Configuration of image forming apparatus 1] Fig. 1 is a front cross-sectional view showing the structure of an image forming apparatus 1 including a document reading device 5 according to an embodiment of the present invention. Fig. 2 is a block diagram showing the configuration of the image forming apparatus 1.

[0012] 1 and 2, the image forming apparatus 1 is a multifunction machine having multiple functions such as a copy function, a transmission function, a printer function, and a facsimile function, etc. The image forming apparatus 1 includes a document transport unit 6, an image reading unit 11, an image forming unit 12, a fixing unit 13, a paper feed unit 14, a display unit 15, an operation unit 16, a transport unit 17, etc.

[0013] The document transport unit 6 transports the document placed on the document placement tray 24. The image reading unit 11 reads the document by a document moving method for optically reading the document transported by the document transport unit 6, or by a document fixed method for optically reading the document placed on the contact glass 52, and generates image data representing the document image. The configurations of the document transport unit 6 and the image reading unit 11 will be described in detail later.

[0014] The image forming unit 12 includes a photoconductor drum, a charging device, an exposure device, a developing device, and a transfer device. The image forming unit 12 forms a toner image on the recording paper P transported along the transport path T by the transport unit 17 based on image data generated by the image reading unit 11 or image data input via the communication unit 22.

[0015] The fixing unit 13 heats and pressurizes the recording paper P on which the toner image has been formed by the image forming unit 12, thereby fixing the toner image to the recording paper P. The recording paper P on which the toner image has been fixed by the fixing unit 13 is transported by the transport unit 17 and discharged to the discharge tray 8.

[0016] The paper feed unit 14 includes a manual feed tray and multiple paper feed cassettes. The paper feed unit 14 uses a pickup roller to pull out recording paper P stored in one of the multiple paper feed cassettes or recording paper placed on the manual feed tray, and feeds the recording paper to the transport path T.

[0017] The display unit 15 is a liquid crystal display, an organic light-emitting diode (EL) display, etc. The display unit 15 displays various screens for each process that can be executed by the image forming apparatus 1.

[0018] The operation unit 16 includes a plurality of hard keys such as a start key 16A for inputting an instruction to start execution of each process executable by the image forming apparatus 1. The operation unit 16 also includes a touch panel 16B disposed on top of the display unit 15. User instructions are input into the operation unit 16. The operation unit 16 is an example of an input unit in the claims.

[0019] The transport unit 17 includes a transport roller pair 17A, a discharge roller pair 17B, etc., and a transport motor connected to the transport roller pair 17A and the discharge roller pair 17B, etc. The transport motor is driven to rotate the transport roller pair 17A and the discharge roller pair 17B, etc., so that the recording paper P fed by the paper feed unit 14 is transported along the transport path T toward the image forming unit 12 and the discharge tray 8.

[0020] The image forming apparatus 1 also includes a control unit 100. The control unit 100 includes a processor, a random access memory (RAM), a read only memory (ROM), etc. The processor is, for example, a central processing unit (CPU), a micro processing unit (MPU), or an application specific integrated circuit (ASIC).

[0021] The control unit 100 is electrically connected to the document transport section 6, the image reading section 11, the image forming section 12, the fixing section 13, the paper feeding section 14, the display section 15, the operation section 16, the transport section 17, the HDD (Hard Disk Drive) 18, the image processing section 19, the image memory 20, the facsimile communication section 21, and the communication section 22. The document transport section 6, the image reading section 11, the display section 15, the operation section 16, the HDD 18, and the control unit 100 constitute the document reading device 5.

[0022] The control unit 100 functions as the control unit 10 by the processor executing a control program stored in the ROM or HDD 18. The control unit 10 is responsible for the overall control of the image forming apparatus 1. In other words, the control unit 10 controls the operation of each part of the image forming apparatus 1. Note that the control unit 10 may be configured by a logic circuit, regardless of the operation based on the control program.

[0023] The HDD 18 is a large-capacity storage device for storing various data such as image data. The HDD 18 stores various control programs for implementing general operations of the image forming apparatus 1. The HDD 18 stores, as one of the various control programs, a conveyance control program for executing a horizontal conveyance process according to one embodiment of the present invention.

[0024] The image processing unit 19 performs image processing as necessary on the image data generated by the image reading unit 11. The image memory 20 includes an area for temporarily storing the image data generated by the image reading unit 11. The facsimile communication unit 21 connects to a public line and transmits and receives image data via the public line.

[0025] The communication unit 22 includes a communication module such as a LAN (Local Area Network) board, etc. The communication unit 22 performs data communication with an external device such as a PC (Personal Computer) via the network.

[0026] Each part of the image forming apparatus 1 is connected to a power source, and each part of the image forming apparatus 1 operates when power is supplied from the power source.

[0027] Here, the configurations of the document transport unit 6 and the image reading unit 11 will be described in detail. Figures 3A and 3B are cross-sectional views showing the document transport unit 6 and the image reading unit 11. Figures 4A and 4B are side views showing the document transport unit 6. As shown in Figures 3A and 3B, the image reading unit 11 includes a first reading unit 40 and a second reading unit 50 built into the document transport unit 6.

[0028] [Configuration of document transport unit 6] The document transport unit 6 includes a document placement tray 24, a first discharge tray 25 and a second discharge tray 26, a first transport path F1 and a second transport path F2, a switching unit 27, a transport unit 28, a distance measurement sensor 29, a paper feed cover 30, and document detection sensors 60A and 60B. The document transport unit 6 is provided on the upper surface of the second reading unit 50 so as to be openable and closable by a hinge or the like. The document transport unit 6 functions as a document pressing cover for pressing down the document MS placed on the contact glass 52.

[0029] The originals MS are placed on the original placement tray 24. The originals MS are discharged to the first discharge tray 25 and the second discharge tray 26. The first transport path F1 is a straight path formed so as to extend from the original placement tray 24 to the first discharge tray 25 without curving. The second transport path F2 is a U-shaped path formed so as to branch off from the first transport path F1 on the downstream side of the first reading unit 40 in the original transport direction, and extend while curving downward toward the second discharge tray 26.

[0030] The switching unit 27 is a claw member provided at a branch point between the first transport path F1 and the second transport path F2. The switching unit 27 switches the document transport direction beyond the branch point to either the first transport path F1 or the second transport path F2. The transport unit 28 includes a pickup roller 31, a paper feed roller pair 32, a shading roller 33, a plurality of transport roller pairs 34, a first discharge roller pair 35, and a second discharge roller pair 36.

[0031] The pickup roller 31 pulls out the documents MS placed on the document placement tray 24 one by one and sends them toward the paper feed roller pair 32. The paper feed roller pair 32 feeds the documents MS sent from the pickup roller 31 to the document transport path F1. The shading roller 33 is disposed opposite the first reading unit 40. A plurality of transport roller pairs 34 are disposed along the first transport path F1 and the second transport path F2.

[0032] The shading roller 33 and the multiple transport roller pairs 34 transport the original MS fed by the paper feed roller pair 32 along the first transport path F1 and the second transport path F2. The first discharge roller pair 35 discharges the original MS transported along the first transport path F1 onto the first discharge tray 25. The second discharge roller pair 36 discharges the original MS transported along the second transport path F2 onto the second discharge tray 26.

[0033] When the document transport direction is switched to the first transport path F1 by the switching unit 27, the transport unit 28 transports the document MS horizontally from the document placement tray 24 to the first discharge tray 25 via the first transport path F1. When the document transport direction is switched to the second transport path F2 by the switching unit 27, the transport unit 28 transports the document MS from the document placement tray 24 to the branch point via the first transport path F1, and transports the document MS from the branch point to the second discharge tray 26 via the second transport path F2.

[0034] Here, a detailed description will be given of the first discharge tray 25. The first discharge tray 25 rotates around a predetermined first rotation axis X1 extending in the main scanning direction, for example, by a hinge mechanism. The first discharge tray 25 is configured to be movable. By rotating, the first discharge tray 25 is in a closed state shown in FIG. 3A or in an open state shown in FIG. 3B. When in the open state, the first discharge tray 25 is capable of receiving the discharged document MS. Also, as shown in FIGS. 4A and 4B, an opening 25A is formed in the first discharge tray 25. The first discharge tray 25 is also configured to be slidable along the main scanning direction.

[0035] The distance measuring sensor 29 detects the state of the first discharge tray 25. In this embodiment, a reflective optical sensor including a light emitting element that emits light toward the opening 25A of the first discharge tray 25 in the open state and is provided at a position where the emitted light passes through the opening, and a light receiving element that receives the emitted light reflected by the document MS on the first discharge tray 25 in the open state is used as the distance measuring sensor 29. The control unit 10 calculates the distance to the reflecting object by using the phase difference between the light emitted by the light emitting element and the reflected light received by the light receiving element. The distance measuring sensor 29 is an example of a first detection unit in the claims.

[0036] The paper feed cover 30 forms a part of a housing 37 that includes the first transport path F1, the first reading unit 40, the transport unit 28, etc. The paper feed cover 30 has a first rotation axis X1. That is, the paper feed cover 30 supports the first discharge tray 25 rotatably about the first rotation axis X1 with the first discharge tray 25 extending outward from the housing 37. The cover 30 is rotated about a predetermined second rotation axis X2 that extends parallel to the first rotation axis X1. The frame is configured to be rotatable by, for example, a hinge mechanism.

[0037] The feed cover 30 rotates to take a closed state shown in Fig. 3A and Fig. 3B or an open state shown in Fig. 6 relative to the housing 37. When the feed cover 30 is in the closed state, it covers each part inside the housing 37, such as the first transport path F1, the first reading unit 40, and the transport unit 28, from above. When the feed cover 30 is in the open state, it opens and exposes each part inside the housing 37.

[0038] The length of the first discharge tray 25 in the main scanning direction is shorter than the length of the paper feed cover 30 in the main scanning direction. When the first discharge tray 25 is in the closed state, it is stored in a recessed portion provided on the surface of the paper feed cover 30 in a state where it is folded to shorten its length. As shown in FIG. 4A, when the first discharge tray 25 is in the closed state, it is disposed at a predetermined first position where the position of the opening 25A and the position of the distance measuring sensor 29 do not coincide with each other in the main scanning direction. In this case, the optical path of the distance measuring sensor 29 is blocked by the first discharge tray 25.

[0039] The first discharge tray 25 is provided in the paper feed cassette 30 so as to be slidable in the direction of the arrow shown in FIG. 4A (for example, horizontally; in this case, the main scanning direction) when in the closed state. The first discharge tray 25 is configured to be slidable to a predetermined second position where the position of the opening 25A and the position of the distance measuring sensor 29 coincide with each other in the main scanning direction. The first discharge tray 25 is also configured to be rotatable toward and away from the paper feed tray 30 when in the second position. A first discharge tray 25 is provided on the side portion of the paper feed cassette 30 below the first rotation axis X1. A support portion 30A is provided to prevent the first discharge tray 25 from rotating.

[0040] When opening the first discharge tray 25, the user first slides the first discharge tray 25 from the closed state in the direction of the arrow shown in FIG. 4A (i.e., the main scanning direction). As shown in FIG. 4B, the user slides the first discharge tray 25 to the second position. The user then rotates the first discharge tray 25 to a predetermined third position where the rotation is prevented by the support portion 30A. This opens the first discharge tray 25. At this time, the opening 25A of the first discharge tray 25 is positioned to pass light emitted by the light-emitting element of the distance measurement sensor 29.

[0041] The document detection sensors 60A and 60B detect the presence or absence of the document MS on the first conveying path F1. The document detection sensors 60A and 60B are not particularly limited as long as they can detect the presence or absence of the document MS, but here, a reflective optical sensor including a light emitting element and a light receiving element is used. The document detection sensors 60A and 60B are provided on the upstream side and downstream side in the document conveying direction along the first conveying path F1, respectively. The document detection sensors 60A and 60B output an OFF signal when they do not detect the document MS, and output an ON signal when they detect the document MS. The control unit 10 detects a conveying error of the document MS on the first conveying path F1 based on the detection results of the document detection sensors 60A and 60B. The document detection sensors 60A and 60B and the control unit 10 are an example of a second detection unit in the claims.

[0042] [Configuration of image reading unit 11] The first reading unit 40 is a contact image sensor (CIS (Contact Image Sensor)) provided on the first transport path F1. The first reading unit 40 reads an image of one side (in this case, the bottom side) of the original MS. Specifically, the first reading unit 40 irradiates one side of the original MS transported along the first transport path F1 by the original movement method with light from, for example, an LED (Light Emitting Diode) through a contact glass, receives the light reflected from the one side with a CMOS (Complementary Metal Oxide Semiconductor) image sensor, and reads the image of the one side.

[0043] The second reading unit 50 includes a contact glass 51, a contact glass 52, a white reference plate 53, a carriage 54, an optical system unit 55, a condenser lens 56, and a CCD (Charge Coupled Device) sensor 57. The carriage 54 includes a linear LED (Light Emitting Diode) array 54A for irradiating light onto the document MS, and a mirror 54B for receiving light reflected by the document MS and reflecting it toward the optical system unit 55.

[0044] The optical system unit 55 includes mirrors 55A and 55B. The mirror 55A reflects the light guided from the mirror 55B and guides it to the mirror 55B. The mirror 55B reflects the light guided from the mirror 55A and guides it to the CCD sensor 57 via the condenser lens 56. The carriage 54 and the optical system unit 55 are configured to be movable back and forth in the sub-scanning direction by a moving mechanism.

[0045] The second reading unit 50 reads an image of the other side (top side in this case) of the original MS transported along the second transport path F2 by the original movement method. Specifically, the second reading unit 50 irradiates the other side of the original MS passing over the contact glass 51 with light from the LED array 54A while the carriage 54 and the optical system unit 55 are stationary at the home position shown in Figures 3A and 3B, and reads the image of the other side by the CCD sensor 57.

[0046] In the case of the fixed original method, the second reading unit 50 reads an image of one side of the original MS placed on the contact glass 52. Specifically, the second reading unit 50 irradiates one side of the original MS placed on the contact glass 52 with light from the LED array 54A while moving the carriage 54 and the optical system unit 55 in the sub-scanning direction at a constant speed, and reads the image of the one side with the CCD sensor 57.

[0047] In this embodiment, the control unit 10 operates in accordance with the above-mentioned transport control program, and when it determines based on the detection result of the distance measurement sensor 29 that the first discharge tray 25 is either closed or full, it does not cause the transport unit 28 to transport the original MS, and when it determines that the first discharge tray 25 is neither closed nor full, it executes a horizontal transport process to cause the transport unit 28 to transport the original MS.

[0048] [Operation] Fig. 5 is a flowchart showing the horizontal transport process. Hereinafter, the operation of the document reading device 5 when the horizontal transport process is executed will be described with reference to Fig. 5 etc. In the following description, it is assumed that the control unit 10 sets the position of the switching unit 27 in the initial state to a position where the document transport direction from the branch point becomes the second transport path F2.

[0049] It is assumed that the user places multiple documents MS face down on the document placement tray 24, and uses the operation unit 16 to specify single-sided reading and input instructions to specify the first discharge tray 25 as the discharge destination of the documents MS. When the control unit 10 receives the above instruction (i.e., an instruction to read documents by the first reading unit 40) via the operation unit 16, it starts the horizontal conveyance process shown in Fig. 5. When the horizontal conveyance process starts, the control unit 10 determines whether the first discharge tray 25 is in a closed state based on the detection result of the distance measurement sensor 29 (step S10).

[0050] Specifically, the control unit 10 calculates the distance to the reflective object based on the detection result of the distance measuring sensor 29, and determines that the first discharge tray 25 is in the closed state if the calculated distance is less than a first threshold value, and otherwise determines that the first discharge tray 25 is not in the closed state. The first threshold value is not particularly limited as long as it is a value that can determine that the first discharge tray 25 is in the closed state, but here, it is assumed that the control unit 10 presets the first threshold value to "0.5 (cm)".

[0051] (1) When the first discharge tray 25 is in the closed state When the first discharge tray 25 is in the closed state, the distance between the first discharge tray 25 and the distance measuring sensor 29 is less than 0.5 cm, so the control unit 10 calculates a value less than the first threshold value (e.g., 0.3 (cm)) as the distance to the reflective object based on the detection result of the distance measuring sensor 29. Therefore, the control unit 10 determines that the first discharge tray 25 is in the closed state (YES in step S10), and causes the display unit 15 to display a first message such as "Please open the discharge tray" to prompt the user to open the first discharge tray 25 without causing the transport unit 28 to start transporting the document MS (step S11). After the process of step S11, the control unit 10 proceeds to the process of step S10.

[0052] (2) When the first discharge tray 25 is in the open state When the first discharge tray 25 is in the open state and there is a document MS on the first discharge tray 25, the distance between the uppermost document MS on the first discharge tray 25 and the distance measuring sensor 29 is 0.5 cm or more. Therefore, the control unit 10 calculates a value equal to or greater than the first threshold as the distance to the reflecting object. On the other hand, when there is no document MS on the first discharge tray 25, the light emitted from the light-emitting element of the distance measuring sensor 29 passes through the opening 25A of the discharge tray 25, and the light-receiving element does not receive the reflected light. Therefore, the control unit 10 does not obtain a detection result and does not calculate the distance to the reflecting object.

[0053] In either of these cases, the control unit 10 determines that the first discharge tray 25 is not in a closed state (NO in step S10), and determines whether the first discharge tray 25 is full or not based on the detection result of the distance measuring sensor 29 (step S12). Specifically, the control unit 10 determines that the first discharge tray 25 is full when the distance to the reflective object calculated in step S10 is less than a predetermined second threshold value that is greater than the first threshold value, and determines that the first discharge tray 25 is not full in other cases. The second threshold value is not particularly limited as long as it is a value that can determine that the first discharge tray 25 is full, but here, it is assumed that the control unit 10 presets the second threshold value to "2.0 (cm)".

[0054] (2-1) When the first discharge tray 25 is full When the first discharge tray 25 is full, the distance between the top document MS on the first discharge tray 25 and the distance measuring sensor 29 is less than 2.0 cm, so the control unit 10 calculates a value less than the second threshold value (e.g., 1.9 (cm)) as the distance to the reflecting object based on the detection result of the distance measuring sensor 29. Therefore, the control unit 10 determines that the first discharge tray 25 is full (YES in step S12), and causes the display unit 15 to display a second message such as "Please remove the documents on the discharge tray" to prompt the user to resolve the full state without causing the conveying unit 28 to start conveying the documents MS (step S13). After processing step S13, the control unit 10 proceeds to processing step S10.

[0055] (2-2) When the first discharge tray 25 is not full When the first discharge tray 25 is not full and there are documents MS on the first discharge tray 25, the distance between the top document MS on the first discharge tray 25 and the distance measuring sensor 29 is 2.0 cm or more, so the control unit 10 calculates a value equal to or greater than the second threshold as the distance to the reflecting object based on the detection result of the distance measuring sensor 29. On the other hand, when there are no documents MS on the first discharge tray 25, the light emitted from the light-emitting element of the distance measuring sensor 29 passes through the opening 25A of the discharge tray 25, so the light-receiving element does not receive the reflected light. Therefore, the control unit 10 does not obtain a detection result and does not calculate the distance to the reflecting object.

[0056] In either of these cases, the control unit 10 determines that the first discharge tray 25 is not full (NO in step S12), and moves the position of the switching unit 27 to switch the document transport direction beyond the branch point to the first transport path F1 (step S14). After the process of step S14, the control unit 10 causes the transport unit 28 to start transporting the document MS (step S15).

[0057] Specifically, the control unit 10 controls the pickup roller 31 and the feed roller pair 32 to feed the originals MS one by one to the original transport path F1, and controls the shading roller 33 and the transport roller pair 34 to transport the fed originals MS horizontally along the first transport path F1. The control unit 10 controls the first reading unit 40 to read an image on one side (the bottom side in this case) of the originals MS transported along the first transport path F1. The control unit 10 controls the first discharge roller pair 35 to discharge the originals MS that have passed through the first reading unit 40 onto the first discharge tray 25.

[0058] After the process of step S15, the control unit 10 determines that the discharge of all the originals MS is not complete until the discharge of all the originals MS is complete (NO in step S22), and determines whether or not a transport error has been detected based on the detection results of the original detection sensors 60A and 60B (step S16). Specifically, the control unit 10 determines that a transport error has been detected when the original detection sensor 60B does not input an ON signal within a predetermined time from the input of an ON signal by the original detection sensor 60A, and determines that a transport error has not been detected in other cases.

[0059] (3) If a transport error is detected If a paper jam of the original MS occurs in the original transport path F1 and an ON signal is not input by the original detection sensor 60B within a predetermined time from the input of an ON signal by the original detection sensor 60A, the control unit 10 determines that a transport error has been detected (YES in step S16) and causes the transport unit 28 to stop transporting the original MS (step S17).

[0060] After the process of step S17, the control unit 10 determines whether or not there is a document MS on the first discharge tray 25 based on the detection result of the distance measurement sensor 29 (step S18). Specifically, when the light receiving element of the distance measurement sensor 29 does not receive reflected light and no detection result is obtained, the control unit 10 determines that there is no document MS on the first discharge tray 25, and in other cases (i.e., when the light receiving element receives reflected light), it determines that there is a document MS on the first discharge tray 25.

[0061] (3-1) When a document MS is present on the discharge tray 25 When a document MS is present on the discharge tray 25, the light emitted from the light-emitting element of the distance measuring sensor 29 is reflected by the document MS on the discharge tray 25, and the light-receiving element receives the reflected light and outputs a detection result. Therefore, the control unit 10 determines that a document MS is present on the first discharge tray 25 (YES in step S18), and causes the display unit 15 to display a third message such as "Please remove all documents from the discharge tray" to urge the removal of all documents MS from the first discharge tray 25 (step S19). After processing step S19, the control unit 10 proceeds to processing step S18.

[0062] (3-2) When there is no original MS on the discharge tray 25 If no document MS is present on the discharge tray 25, the light emitted by the light-emitting element of the distance measuring sensor 29 passes through the opening 25A of the discharge tray 25, so the light-receiving element does not receive the reflected light, and the control unit 10 cannot obtain a detection result. Therefore, the control unit 10 determines that no document MS is present on the first discharge tray 25 (NO in step S18), and causes the display unit 15 to display a fourth message such as "Please open the paper feed cover and remove the document" to encourage the user to open the paper feed cover 30 (step S20).

[0063] After the process of step S20, control unit 10 repeats the process of determining that the transport error has not been resolved (NO in step S21) until it receives an input indicating that the transport error has been resolved (in this case, pressing start key 16A) via operation unit 16. For example, it is assumed that the user opens paper feed cover 30, removes the jammed document MS, and then presses start key 16A.

[0064] When the control unit 10 receives a press of the start key 16A, it determines that the transport error has been resolved (YES in step S21) and proceeds to the process of step S15. When the control unit 10 does not detect a transport error based on the detection results of the document detection sensors 60A and 60B (NO in step S16) and the first discharge roller pair 35 has completed discharging all of the documents MS (YES in step S22), it ends the horizontal transport process.

[0065] According to the above embodiment, when an instruction to read a document by the first reading unit 40 is input to the operation unit 16, if the control unit 10 determines based on the detection result of the distance measurement sensor 29 that the first discharge tray 25 is either closed or full, it does not cause the transporting unit 28 to transport the document MS or the first reading unit 40 to read the image, but if it determines that the first discharge tray 25 is neither closed nor full, it causes the transporting unit 28 to transport the document MS and the first reading unit 40 to read the image.

[0066] In this way, when the first discharge tray 25 is either in a closed state or a full state, i.e., when there is a high possibility that the transport of the original MS will cause the original MS to become clogged, the original MS is not transported, thereby preventing the original MS from becoming clogged in the first transport path F1.

[0067] Furthermore, according to the above embodiment, when an instruction to read a document by the first reading unit 40 is input to the operation unit 16, if the control unit 10 determines that the first discharge tray 25 is closed based on the detection result of the distance measurement sensor 29, it causes the display unit 15 to display a first message to urge the user to open the first discharge tray 25. If the control unit 10 determines that the first discharge tray 25 is full, it causes the display unit 15 to display a second message to urge the user to resolve the full state.

[0068] This makes it possible to remove the cause of the jamming of the original MS before it is transported, so that the jamming of the original MS in the first transport path F1 can be prevented more reliably.

[0069] However, as shown in Figure 6, when the paper feed cover 30 is opened while a document MS is placed on the first discharge tray 25, the first discharge tray 25 tilts as the paper feed cover 30 rotates, which may cause the document MS to fall off the first discharge tray 25.

[0070] In contrast, according to the above embodiment, when the control unit 10 detects a transport error based on the detection results of the document detection sensors 60A and 60B and detects the presence of documents MS on the first discharge tray 25 based on the detection result of the distance measurement sensor 29, the control unit 10 causes the display unit 15 to display a third message to prompt the user to remove all documents MS from the first discharge tray 25. When the control unit 10 detects a transport error and detects that there are no documents MS on the first discharge tray 25, the control unit 10 causes the display unit 15 to display a fourth message to prompt the user to open the paper feed cover 30.

[0071] This makes it possible to prevent the feed cover 30 from being opened while the originals MS are placed on the first discharge tray 25, and therefore to prevent the originals MS from falling off the first discharge tray 25.

[0072] According to the above embodiment, the control unit 10 calculates the distance to the reflecting object based on the detection result of the distance measuring sensor 29, detects the closed state of the first discharge tray 25 when the distance to the reflecting object is less than the first threshold, detects the full state of the first discharge tray 25 when the distance to the reflecting object is equal to or greater than the first threshold and less than the second threshold, and does not detect the closed state or the full state when the distance to the reflecting object is equal to or greater than the second threshold or when the light receiving element does not receive reflected light. The control unit 10 also detects the absence of a document on the first discharge tray 25 when the light receiving element of the distance measuring sensor 29 does not receive reflected light, and detects the presence of a document on the first discharge tray 25 when the light receiving element receives reflected light.

[0073] This allows various states of the first discharge tray 25 to be detected by one distance measuring sensor 29, so that the number of parts can be reduced and manufacturing costs can be cut down compared to a case where a separate sensor is provided for each state.

[0074] (Other variations) In the above embodiment, the distance measuring sensor 29 is used as the first detection unit, but the present invention is not limited to such an embodiment. For example, as shown in Fig. 7, the first detection unit may be a first sensor 29A that detects the open / closed state of the first discharge tray 25, a second sensor 29B that detects the full state of the first discharge tray 25, and a third sensor 29C that detects the presence or absence of a document on the first discharge tray 25. The first sensor 29A, the second sensor 29B, and the third sensor 29C are not particularly limited, but for example, a reflective optical sensor including a light emitting element and a light receiving element may be used.

[0075] In the above embodiment, the image forming unit 12 etc. records an image on the recording paper P, but the present invention is not limited to such an embodiment. The image forming unit 12 etc. may record an image on other recording media, not limited to the recording paper P. An example of other recording media is an overhead projector (OHP) sheet.

[0076] The present invention is not limited to the configuration of the above embodiment, and various modifications are possible. For example, in the above embodiment, a color multifunction machine is used as the image forming apparatus equipped with the document reading device, but this is only one example, and other image forming apparatuses such as a monochrome multifunction machine, a copy machine, or a facsimile machine may be used.

[0077] The configuration and processing of the embodiment described above with reference to FIGS. 1 to 7 are merely one embodiment of the present invention, and it is not intended that the present invention be limited to these configurations and processing. [Explanation of symbols]

[0078] 1. Image forming device 5 Document reader 10 Control section 12 Image forming section 15 Display 16 Control section 24 Document tray 25 First output tray 28 Conveyor 29 Distance Sensor 30 Paper feed cover 40 First reading section 60A, 60B Document detection sensor F1 First conveyor route

Claims

1. a document tray on which documents are placed; a first discharge tray that is turned into a closed state or an open state by rotating about a predetermined first rotation axis; a first transport path extending from the document placement tray to the first discharge tray without curving; a first reading unit provided in the first transport path and configured to read an image on one side of the document; a transport unit configured to transport the document from the document placement tray to the first discharge tray through the first transport path; an input unit for inputting user instructions; a first detection unit that detects a state of the first discharge tray; a control unit that, when an instruction to read a document by the first reading unit is input to the input unit, prevents the transport unit from transporting the document and the first reading unit from reading the image if the first detection unit detects the closed state of the first discharge tray, and causes the transport unit to transport the document and the first reading unit to read the image if the first detection unit does not detect the closed state.

2. Further comprising a display unit, 2. The document reading device according to claim 1, wherein when the document reading instruction is input to the input unit, if the first detection unit detects the closed state, the control unit displays a first message on the display unit to prompt the user to open the first output tray.

3. A display unit; a paper feed cover that forms part of a housing that contains the first transport path, the first reading unit, and the transport unit therein, supports the first discharge tray rotatably about the first rotation axis with the first discharge tray extending outward from the housing, and rotates about a predetermined second rotation axis that extends parallel to the first rotation axis to become a closed state or an open state with respect to the housing, covering the first transport path, the first reading unit, and the transport unit from above in the closed state, and exposing the first transport path, the first reading unit, and the transport unit in the open state; a second detection unit that detects a transport error of the document in the first transport path, The control unit When the second detection unit detects the transport error and the first detection unit detects the presence of the document on the first discharge tray, displaying a second message on the display unit to prompt the removal of all the document from the first discharge tray, 2. The document reading device of claim 1, wherein when the second detection unit detects the transport error and the first detection unit detects that the document is not present on the first output tray, the display unit displays a third message to prompt the user to open the paper feed cover.

4. The first discharge tray has an opening formed therein, the first detection unit includes a distance measuring sensor including a light emitting element that emits light toward the opening of the first discharge tray in the open state and is provided at a position where the emitted light passes through the opening, and a light receiving element that receives light of the emitted light reflected by the document on the first discharge tray, The control unit Calculating the distance to the reflecting object based on the detection result of the distance measuring sensor; When the distance to the reflective object is less than a predetermined first threshold, the closed state of the first discharge tray is detected; When the distance to the reflecting object is equal to or greater than the first threshold value, or when the light receiving element does not receive the reflected light, the closed state is not detected, 4. The document reading device of claim 3, wherein when the light receiving element does not receive the reflected light, it detects that the document is not present on the first discharge tray, and when the light receiving element receives the reflected light, it detects that the document is present on the first discharge tray.

5. a document reading device according to claim 1 or claim 3; an image forming unit that forms the image read by the document reading device on a recording medium;

Images