Document conveying device and image forming apparatus

Abstract

To reduce the time from the start of an instruction to read documents issued by a user until when reading of the documents is started, while preventing a reduction in convenience related to proper arrangement of documents.SOLUTION: A document conveying device comprises a control unit that controls the drive of a raising and lowering mechanism that raises and lowers a document placement tray 61 between a lower limit position LP and an upper limit position UP, after the lapse of predetermined standby time from the time point when documents on the document placement tray 61 are detected by a document detection sensor, and moves the document placement tray 61 and stops it at a predetermined standby position SP between the upper limit position UP and the lower limit position LP.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a document transport device that transports a document to a document reading unit and an image forming apparatus including the same. [Background technology]

[0002] Some document transport devices, which use a feed roller to feed documents placed on a document tray one by one and transport the fed documents to a reading position in a document reading unit, raise the document tray when a user issues a document reading instruction (a scan instruction or a copy instruction) to a position (upper limit position) where the top surface of the top sheet of the document placed on the document tray presses against the feed roller.

[0003] However, because the document tray is normally lowered to its lowest position, the document tray must be moved up a long distance from the lowest position to the highest position in order to start scanning the document, which means that a long time is required between the user issuing the document scanning command and the document scanning actually starting. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-005048 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned Patent Document 1 describes that when the document detection sensor detects a document on the document loading tray (i.e., when the user places a document on the document loading tray), the document loading tray is immediately raised to its upper limit position.

[0006] However, as described in Patent Document 1 above, if a user lifts the document loading tray immediately after placing a document on it, the document loading tray will come into contact with the user's hand as it is lifting, interfering with the user's work, and it will also be difficult to use the cursor to organize the documents or align the documents widthwise, reducing convenience.

[0007] The present invention has been made in consideration of the above circumstances, and aims to shorten the time from when a user issues an instruction to read a document to when the document reading starts, while ensuring convenience during document reading. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided a document transporting device including an operation unit that receives a document reading instruction, a document placement tray that moves up and down on which documents are placed, a document detection sensor that detects the presence or absence of a document on the document placement tray, a document discharge tray, a document transport mechanism that has a feed roller that is provided above the document placement tray and feeds out the documents placed on the document placement tray one by one, transports the documents fed out by the feed roller to a reading position by a document reading unit, and discharges the documents onto the document discharge tray, and a document transport mechanism that moves the document placement tray from a lower limit position of the lifting operation to a position where the top surface of the top sheet of the documents placed on the document placement tray is lowered. The document feeder includes a lifting mechanism that raises and lowers the document feed tray to an upper limit position where it presses against the feed roller, and a control unit that, after a predetermined first waiting time has elapsed since the document detection sensor detected the document on the document feed tray, causes the lifting mechanism to move the document feed tray to a predetermined waiting position between the upper limit position and the lower limit position and stop the document feed tray there, and when the document reading instruction is received by the operation unit and the document transport mechanism transports the document fed by the feed roller to the reading position, causes the lifting mechanism to raise the document feed tray again to the upper limit position.

[0009] An image forming apparatus according to one aspect of the present invention includes the document transport device according to the above aspect of the present invention, and an image forming section that forms an image on a recording medium. [Effects of the Invention]

[0010] According to the present invention, the document loading tray is placed on standby at a standby position closer to the upper limit position than the lower limit position, thereby shortening the time required from the user's document scanning instruction to the start of document scanning. Furthermore, the document loading tray is raised not immediately after the user places a document on the document loading tray, but after a standby time has elapsed, ensuring convenience during document scanning. This ensures convenience during document scanning while shortening the time required from the user's document scanning instruction to the start of document scanning. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view showing the appearance of an image forming apparatus including a document transport device according to an embodiment of the present invention; [Figure 2] FIG. 10 is a perspective view showing another example of a document transport device. [Figure 3] 3 is a cross-sectional view of the document transport device shown in FIG. 2. FIG. [Figure 4] FIG. 2 is a diagram schematically illustrating a cross section of the document transport device. [Figure 5] 1A is a diagram showing a state in which the document placement tray has risen to its upper limit position, and FIG. 1B is a diagram showing a state in which the document placement tray has fallen to its lower limit position. [Figure 6] FIG. 2 is a functional block diagram illustrating a main internal configuration of the image forming apparatus. [Figure 7] 1A is a diagram showing a state in which the document placement tray is waiting at a standby position, and FIG. 1B is a diagram showing an intermediate position. [Figure 8] 10 is a flowchart illustrating an example of control of raising and lowering the document placement tray in the document transport device. [Figure 9] 10 is a flowchart illustrating an example of control of raising and lowering the document placement tray in the document transport device. [Figure 10]10 is a flowchart illustrating an example of control of raising and lowering a document placement tray in a document transport device. DETAILED DESCRIPTION OF THE INVENTION

[0012] An original transport device and an image forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a perspective view showing the appearance of an image forming apparatus equipped with an original transport device according to an embodiment of the present invention.

[0013] The image forming device 1 is a multifunction device that combines multiple functions, such as a copy function, a printer function, a scanner function, and a facsimile function, and is configured to include a document transport device 6, a document reading unit 5, an image forming unit 12, a paper feed unit 14, and an operation unit 470.

[0014] The document transport device 6 is configured to be openable and closable by a hinge or the like (not shown) on the top surface of the document reading unit 5, and functions as a document pressing cover when reading a document placed on a platen glass (not shown). The document transport device 6 also includes a document placement tray 61 on which documents are placed and which moves up and down, and a document discharge tray 62 provided below the document placement tray 61. The document transport device 6 supplies documents placed on the document placement tray 61 to the document reading unit 5 one by one, and discharges the documents to the document discharge tray 62.

[0015] The document reading unit 5 includes a scanner and the like, and reads the document fed from the document transport device 6 or reads the document placed on the platen glass. The document reading unit 5 is also capable of sequentially reading multiple document images sent from the document transport device 6.

[0016] The following describes the case where a document reading operation is performed by the image forming apparatus 1. The document reading unit 5 optically reads an image of a document supplied to the document reading unit 5 by the document transport device 6 or a document placed on the platen glass, and generates image data. The image data generated by the document reading unit 5 is stored in an image memory or the like (not shown).

[0017] The following describes an image forming operation performed by the image forming apparatus 1. The image forming unit 12 is equipped with a photosensitive drum, charging device, exposure device, developing device, and primary transfer device for each color, and is a mechanism for forming an image on recording paper as a recording medium by secondary transfer via an intermediate transfer belt. The image forming unit 12 forms a toner image on recording paper fed from the paper feed unit 14 based on image data generated by a document reading operation, image data stored in an image memory, etc., and image data received from a computer connected via a network, to create a printed matter.

[0018] The recording paper on which the toner image has been formed by the image forming unit 12 undergoes a fixing process in a fixing unit 13 (FIG. 6) described later, and the recording paper after the fixing process is discharged onto a discharge tray 151.

[0019] The paper feed unit 14 includes a plurality of paper feed cassettes 141, and further includes a pickup roller that picks up recording paper from the paper feed cassettes 141 and feeds it to the image forming unit 12, a transport roller, a transport path, and a rotation drive mechanism for each roller.

[0020] The operation unit 470 includes various hard keys operated by the user, and receives instructions from the user, such as an instruction to perform an image forming operation, for various operations and processes that can be performed by the image forming apparatus 1, in response to the operation of the hard keys. For example, the operation unit 470 receives an instruction to read a document (a scan instruction or a copy instruction).

[0021] The operation unit 470 includes a display unit 473 that displays operation guides and the like to the operator. The operation unit 470 also receives input of instructions from the user based on the user's operation (touch operation) on the screen displayed on the display unit 473 via a touch panel that the display unit 473 has.

[0022] The display unit 473 is composed of an LCD (Liquid Crystal Display) or the like. When the operator touches a button or key displayed on the screen, the touch panel receives an instruction associated with the touched position. In this case, the touch panel functions as an operation unit.

[0023] Fig. 2 is a perspective view showing another example of the document transport device 6. Fig. 3 is a diagram showing a cross section of the document transport device 6 shown in Fig. 2. Fig. 4 is a diagram showing a schematic cross section of the document transport device 6.

[0024] The document transport device 6 includes a document loading tray 61, a document discharge tray 62, a document transport mechanism 63 (FIG. 4) that transports documents loaded on the document loading tray 61 to the document discharge tray 62, and a lifting mechanism 64 (FIG. 4) that lifts and lowers the document loading tray 61. The lifting and lowering operation of the document loading tray 61 by the document transport device 6 and the drive control of each part related to document reading are performed by a control unit 100, which will be described later.

[0025] The document placement tray 61 includes a document placement table 21 (FIG. 2) on which the document is placed, a cursor 22 (FIG. 2) configured to be slidable on the top surface of the document placement table 21 in the document width direction perpendicular to the document transport direction, and a document width guide 23 erected on the cursor 22 and abutting against the document placed on the document placement table 21 in the document width direction to regulate the width of the document.

[0026] The document transport mechanism 63 includes a document transport path 31, a feed mechanism 32 for feeding out documents placed on the document loading tray 61 one by one, a plurality of pairs of transport rollers 33 arranged along the document transport path 31, and a pair of discharge rollers 34 for discharging the documents onto the document discharge tray 62.

[0027] An opening 65 is provided at the lowest end of the document transport path 31. That is, the document transport device 6 has the opening 65 formed on its underside at a portion facing the platen glass 51, which is the reading position in the document reading unit 5 (FIG. 1). The document fed by the feeding mechanism 32 and transported along the document transport path 31 is transported to the underside (opening 65) of the document transport device 6, where the image of the document is read by the document reading unit 5. In addition, a white plate 66 for shading correction is provided directly above the opening 65 (at a position directly above the platen glass 51).

[0028] The document that has passed through the opening 65 is transported toward the discharge roller pair 34 by the transport roller pair 33 provided downstream of the opening 65 in the transport direction, and is discharged onto the document discharge tray 62 by the discharge roller pair 34.

[0029] The feeding mechanism 32 includes a feeding roller 41 that feeds out the documents placed on the document tray 61 one by one, a drive roller 42, a driven roller 43, a belt 44 wound around the drive roller 42 and the driven roller 43, and an auxiliary roller 45 provided below the belt 44.

[0030] The payout roller 41, drive roller 42, driven roller 43, and belt 44 are provided inside a box-shaped holder 46 that is open at the bottom. The holder 46 can swing around the drive shaft 421 of the drive roller 42, and the driving force of the drive shaft 421 is transmitted to the payout roller 41 by a transmission mechanism such as a gear (not shown).

[0031] A pressure detection sensor 67 is provided on the upper part of holder 46 to detect that an appropriate load is applied between the upper surface of the top sheet of documents placed on document tray 61 and feed roller 41. In other words, pressure detection sensor 67 serves as an upper limit sensor that can detect that document tray 61 has risen to the upper limit position where the upper surface of the top sheet of documents placed on document tray 61 presses against feed roller 41. Document transport device 6 also includes a lower limit sensor 68, which is a mechanical or optical sensor that detects the lower limit position of document tray 61.

[0032] The lifting mechanism 64 includes a lifting lever 47, the tip of which abuts against the document placement tray 61 and raises and lowers the document placement tray 61, and a rotary shaft 48, which is connected to a motor (not shown) and rotates the lifting lever 47. Fig. 5(A) shows a state in which the document placement tray 61 has risen to the upper limit position UP, and Fig. 5(B) shows a state in which the document placement tray 61 has descended to the lower limit position LP.

[0033] 6 is a functional block diagram showing a schematic diagram of the main internal configuration of the image forming apparatus 1. The image forming apparatus 1 includes a control unit 10, a document transport device 6, a document reading unit 5, an image forming unit 12, a fixing unit 13, a paper feeding unit 14, an operation unit 470, and a storage unit 8.

[0034] The fixing unit 13 is a fixing device equipped with a heat roller, a pressure roller, and a drive mechanism for rotating these rollers. The fixing unit 13 heats and presses the recording paper on which the toner image has been formed by the image forming unit 12 at the nip between the two rollers, fixing the toner image to the recording paper. The recording paper that has been fixed is then discharged to the discharge tray 151 (Figure 1).

[0035] The storage unit 8 is a large-capacity storage device such as a hard disk drive (HDD) or a solid state drive (SSD), and stores various control programs and the like.

[0036] The control unit 10 includes a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), and a dedicated hardware circuit. The processor may be, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or an MPU (Micro Processing Unit). The control unit 10 includes a control unit 100.

[0037] The control unit 10 functions as the control unit 100 by the operation of the processor in accordance with the control program stored in the storage unit 8. However, the control unit 100 can also be configured by a hardware circuit, without relying on the operation in accordance with the control program by the control unit 10. Unless otherwise stated below, the same applies to each embodiment.

[0038] The control unit 100 is responsible for overall operational control of the image forming apparatus 1. The control unit 100 is also responsible for overall operational control of the document transport device 6. The control unit 100 is connected to the document transport device 6, the document reading unit 5, the image forming unit 12, the fixing unit 13, the paper feed unit 14, the operation unit 470, and the memory unit 8, and controls the driving of each of these units. For example, the control unit 100 executes various processes required for image formation by the image forming apparatus 1. The control unit 100 is an example of a control unit in the claims.

[0039] The document transport device 6 includes an elevation mechanism 64, a document detection sensor 73, an ejected document detection sensor 74, and a cursor movement detection sensor 75. The document detection sensor 73 is a sensor that detects the presence or absence of a document on the document placement tray 61. The ejected document detection sensor 74 is a sensor that detects the presence or absence of a document on the document ejection tray 62. The cursor movement detection sensor 75 is a sensor that detects the movement of the cursor 22. The document transport device 6 may include a control unit 100, which is an example of a control unit in the claims. The control unit 100 functions as a control unit that controls the operation of each unit of the document transport device 6.

[0040] After a predetermined first waiting time T1 (e.g., 5 seconds) has elapsed since the document detection sensor 73 detected a document on the document loading tray 61, the control unit 100 controls the operation of the lifting mechanism 64 to move the document loading tray 61 to a predetermined waiting position SP between the upper limit position UP and the lower limit position LP and stop it there.

[0041] For example, the control unit 100 controls the driving of the lifting mechanism 64 to raise the document placement tray 61, and when the pressure detection sensor 67 (FIG. 4) detects that a load of a certain level or more has been applied to the feed roller 41, it determines that the document placement tray 61 has reached the upper limit position UP and stops the raising of the document placement tray 61. In other words, the control unit 100 temporarily raises the document placement tray 61 to the upper limit position UP.

[0042] Thereafter, the control unit 100 moves the document placement tray 61 to a standby position SP, which is a predetermined distance PD below the upper limit position UP, and stops the document placement tray 61. The predetermined distance PD may be a small distance (for example, 5 mm) that is sufficient to separate the document from the feed roller 41. The standby position SP is most preferably closer to the upper limit position UP than to the lower limit position LP. FIG. 7A shows the document placement tray 61 waiting at the standby position SP.

[0043] Furthermore, when a document reading instruction is received by the operation unit 470 and the document transport mechanism 63 transports the document fed out by the feed roller 41 to the reading position in the document reading unit 5, the control unit 100 causes the lifting mechanism 64 to again raise the document placement tray 61 to the upper limit position UP. The operation unit 470 receives a user instruction to start scanning or copying the document placed on the document placement tray 61 as a document reading instruction.

[0044] The document transport device 6 equipped with the control unit 100 as its control unit and further equipped with the operation unit 470 is an example of a document transport device within the scope of the claims.

[0045] Furthermore, when the operation unit 470 receives the document reading instruction between the time when the document on the document loading tray 61 is detected by the document detection sensor 73 and the time when the first waiting time T1 has elapsed, the control unit 100 causes the lifting mechanism 64 to raise the document loading tray 61 to the upper limit position UP without waiting for the first waiting time T1 to elapse.

[0046] Furthermore, when document detection sensor 73 no longer detects a document on document placement tray 61 (i.e., when a document is removed from document placement tray 61), if document discharge detection sensor 74 does not detect a document on document discharge tray 62, control unit 100 controls drive of lifting mechanism 64 to lower document placement tray 61 to lower limit position LP after a predetermined second standby time T2 (e.g., 5 seconds) has elapsed since that point. On the other hand, when document detection sensor 73 no longer detects a document on document placement tray 61 but document discharge detection sensor 74 detects a document on document discharge tray 62, control unit 100 controls drive of lifting mechanism 64 to move document placement tray 61 to a predetermined intermediate position MP between upper limit position UP and lower limit position LP after a predetermined third standby time T3 (e.g., 5 seconds) has elapsed since that point, and stops document placement tray 61. FIG. 7B shows the intermediate position MP.

[0047] Furthermore, when the document loading tray 61 is stopped at the intermediate position MP and the document discharge detection sensor 74 no longer detects any documents on the document discharge tray 62, the control unit 100 controls the operation of the lifting mechanism 64 to lower the document loading tray 61 to the lowest position LP after a predetermined fourth waiting time T4 (for example, 5 seconds) has elapsed from that point.

[0048] Next, an example of the control of raising and lowering the document placement tray 61 in the document transport device 6 will be described with reference to the flowcharts shown in Figures 8 to 10. This process is performed when the document detection sensor 73 detects a document placed on the document placement tray 61.

[0049] When the document detection sensor 73 detects a document on the document loading tray 61, the control unit 100 starts a timer built into the control unit 10 from the time of detection to start measuring time (S1), and determines whether the measured time T has reached the first waiting time T1 (S2).

[0050] When the control unit 100 determines that the measured time T has reached the first waiting time T1 (YES in S2), it controls the driving of the lifting mechanism 64 to move the document loading tray 61 to the waiting position SP and stop it (S3).

[0051] Next, the control unit 100 determines whether an instruction to read a document (for example, an instruction to scan or copy) has been received by the operation unit 470 (S4).

[0052] When the control unit 100 determines that the document reading instruction has been accepted (YES in S4), it controls the operation of the lifting mechanism 64 to raise the document loading tray 61 to the upper limit position UP, controls the operation of the document transport mechanism 63 to start transporting the document loaded on the document loading tray 61, and executes the document reading process by having the document reading unit 5 read the image of the document (S5).

[0053] When the control unit 100 determines, based on the detection results of the document detection sensor 73, that all documents placed on the document placement tray 61 have been transported, it controls the driving of the lifting mechanism 64 to lower the document placement tray 61 to the lowest limit position (S6). After this, the process ends. Specifically, the control unit 100 controls the lifting mechanism 64 to continue lowering the document placement tray 61 until the document placement tray 61 is detected by the lower limit sensor 68 (FIG. 4).

[0054] On the other hand, in S4, if the control unit 100 determines that the document reading instruction has not been accepted (NO in S4), it determines whether the document has been removed from the document loading tray 61 based on the detection content by the document detection sensor 73 (S7).

[0055] If the control unit 100 determines that the document has not been removed from the document placement tray 61 and that the document is still placed on the document placement tray 61 (NO in S7), the process returns to S4. On the other hand, if the control unit 100 determines that the document has been removed from the document placement tray 61 (YES in S7), the process proceeds to S11 (FIG. 9).

[0056] Furthermore, in S2, if the control unit 100 determines that the measured time T has not reached the first waiting time T1 (NO in S2), it determines whether the document reading instruction has been received by the operation unit 470 (S8).

[0057] If the control unit 100 determines that the document reading instruction has been received (YES in S8), the process proceeds to S5, where the document reading process is executed. On the other hand, if the control unit 100 determines that the document reading instruction has not been received (NO in S8), the control unit 100 determines whether or not a document has been removed from the document placement tray 61 based on the detection content of the document detection sensor 73 (S9).

[0058] If the control unit 100 determines that the document has not been removed from the document placement tray 61 and that the document is still placed on the document placement tray 61 (NO in S9), the process returns to S2. On the other hand, if the control unit 100 determines that the document has been removed from the document placement tray 61 (YES in S9), the process proceeds to S11 (FIG. 9).

[0059] 9 shows the process that is performed when a document is removed from document placement tray 61. Based on the detection result of discharged document detection sensor 74, control unit 100 determines whether or not a document is present on document discharge tray 62 (S11).

[0060] If the control unit 100 determines that there is no document in the document discharge tray 62 (NO in S11), it resets the measurement time T to 0 (S12), and then determines whether the measurement time T has reached the second waiting time T2 (S13).

[0061] When the control unit 100 determines that the measured time T has reached the second waiting time T2 (YES in S13), it controls the driving of the lifting mechanism 64 to lower the document placement tray 61 to the lowest position LP (S14). After this, the process ends. Note that if a document is placed on the document placement tray 61 and detected by the document detection sensor 73 before the measured time T reaches the second waiting time T2, this process ends and a new process starts from S1.

[0062] On the other hand, if the control unit 100 determines that a document is present in the document discharge tray 62 (YES in S11), it resets the measurement time T to 0 (S15), and then determines whether the measurement time T has reached the third waiting time T3 (S16).

[0063] If the control unit 100 determines that the measured time T has reached the third waiting time T3 (YES in S16), it controls the driving of the lifting mechanism 64 to move the document placement tray 61 to the intermediate position MP and stop it (S17), and the process proceeds to S21 (FIG. 10). Note that if a document is placed on the document placement tray 61 and the document detection sensor 73 detects it before the measured time T reaches the third waiting time T3, this process ends and a new process starts from S1.

[0064] 10 shows the process performed when the document loading tray 61 is on standby at the intermediate position MP. The document loading tray 61 is on standby at the intermediate position MP when there are no documents in the document loading tray 61 but there are documents in the document discharge tray 62.

[0065] The control unit 100 determines whether or not the document has been removed from the document discharge tray 62 based on the detection result of the discharged document detection sensor 74 (S21).

[0066] When the control unit 100 determines that the document has been removed from the document discharge tray 62 (YES in S21), it resets the measurement time T to 0 (S22), and then determines whether the measurement time T has reached the fourth waiting time T4 (S23).

[0067] When the control unit 100 determines that the measured time T has reached the fourth waiting time T4 (YES in S23), it controls the driving of the lifting mechanism 64 to lower the document placement tray 61 to the lowest position LP (S24). After this, the process ends. Note that if a document is placed on the document placement tray 61 and detected by the document detection sensor 73 before the document is removed from the document discharge tray 62 or before the measured time T reaches the fourth waiting time T4, this process ends and a new process starts from S1.

[0068] According to the above embodiment, the document placement tray 61 is placed on standby at the standby position SP, which is closer to the upper limit position UP than the lower limit position LP, so that the time required from when the user issues a document reading instruction until the document reading starts can be shortened.

[0069] Furthermore, the document placement tray 61 is raised not immediately after the user places the document on the document placement tray 61, but after the first standby time T1 has elapsed, ensuring the convenience of the document reading operations, such as document placement and organization. This ensures the convenience of the document reading operations while shortening the time from when the user issues a document reading instruction until the document reading starts.

[0070] Furthermore, the document loading tray 61 is placed on standby not at the upper limit position UP where the document is in contact with the feed roller 41, but at the standby position SP which is a predetermined distance PD below the upper limit position UP, so that a gap is formed between the document loaded on the document loading tray 61 and the feed roller 41. Therefore, even if the document loading tray 61 is placed on standby at the standby position SP, it is easy to insert and remove documents and use the cursor 22.

[0071] Furthermore, if an instruction to read a document is received by the operation unit 470 before the first standby time T1 has elapsed, the document placement tray 61 is raised to the upper limit position UP by the lifting mechanism 64 without waiting for the first standby time T1 to elapse, so that when a user gives an instruction to start scanning or copying, the document reading process can be executed without delay. Furthermore, when a document is removed from the document placement tray 61, the document placement tray 61 can be moved to a position appropriate for the situation at that time.

[0072] Incidentally, a user may use the cursor 22 to organize the documents placed on the document tray 61, but it is not desirable for the document tray 61 to move while the user is using the cursor 22.

[0073] Therefore, in another embodiment, when the cursor movement detection sensor 75 detects the movement of the cursor 22, the control unit 100 does not start moving the document loading tray 61 until a certain time has passed from the point when the cursor movement detection sensor 75 no longer detects the movement of the cursor 22.

[0074] For example, when the cursor movement detection sensor 75 detects the movement of the cursor 22, the control unit 100 stops measuring time and resets the measurement time T to 0, and when the cursor movement detection sensor 75 no longer detects the movement of the cursor 22, it starts measuring time.

[0075] The user may be able to set whether to enable or disable the function of providing a waiting time before moving the document placement tray 61, by having the control unit 100 set it in accordance with an instruction received from the user through operation of the operation unit 470. The length of each waiting time may also be set by the user.

[0076] The present invention is not limited to the configuration of the above-described embodiment, and various modifications are possible. For example, in the above-described embodiment, the control unit 100 of the control unit 10 of the image forming apparatus 1 is an example of a control unit in the claims. However, the document transport device 6 may be provided with a transport control unit including a CPU or the like that controls the overall operation of the document transport device 6, and the transport control unit may perform the processes by the control unit 100 described with reference to FIGS. 8 to 10, and the transport control unit may be an example of a control unit in the claims. Furthermore, in the above-described embodiment, the configuration and processes shown in the above-described embodiment using FIGS. 1 to 10 are merely one embodiment of the present invention, and the present invention is not intended to be limited to these configurations and processes. [Explanation of symbols]

[0077] 1. Image forming device 12 Image forming unit 5 Document reading section 6 Document transport device 21 Document placement table 22 Cursor 23 Document width guide 41 Feed roller 61 Document tray 62 Document output tray 63 Document transport mechanism 64 Lifting mechanism 73 Document detection sensor 74 Ejected document detection sensor 75 Cursor movement detection sensor 100 control section 470 Operation section

Claims

1. an operation unit that receives a document reading instruction; a document tray on which a document is placed and which moves up and down; a document detection sensor that detects whether or not a document is present on the document placement tray; A document ejection tray; a document transport mechanism that is provided above the document placement tray and has a feed roller that feeds out the documents placed on the document placement tray one by one, transports the documents fed out by the feed roller to a reading position by a document reading unit, and discharges the documents to the document discharge tray; an elevating mechanism that elevates the document placement tray from a lower limit position of the elevating operation to an upper limit position at which an upper surface of a top sheet of documents placed on the document placement tray presses against the feed roller; a control unit that, after a predetermined first waiting time has elapsed from the time the document on the document loading tray is detected by the document detection sensor, causes the lifting mechanism to move the document loading tray to a predetermined waiting position between the upper limit position and the lower limit position and stop it, and when the document reading instruction is accepted by the operation unit and the document transport mechanism transports the document fed out by the feed roller to the reading position, causes the lifting mechanism to raise the document loading tray again to the upper limit position.

2. The document transport device of claim 1, wherein when the document reading instruction is received from the operation unit between the time when the document on the document loading tray is detected by the document detection sensor and the time when the first waiting time has elapsed, the control unit causes the lifting mechanism to raise the document loading tray to the upper limit position without waiting for the first waiting time to elapse.

3. further comprising a discharged document detection sensor that detects the presence or absence of a document on the document discharge tray; when the document detection sensor no longer detects the document on the document placement tray and the document discharge sensor no longer detects the document on the document discharge tray, after a predetermined second waiting time has elapsed from that point, the control unit controls the driving of the lifting mechanism to lower the document placement tray to the lower limit position; 2. The document transport device of claim 1, wherein, when the document detection sensor no longer detects a document on the document loading tray but the discharged document detection sensor detects a document on the document ejection tray, the lifting mechanism lowers the document loading tray to a predetermined intermediate position between the upper limit position and the lower limit position and stops the document loading tray after a predetermined third waiting time has elapsed from the time the document was detected on the document ejection tray.

4. The document transport device of claim 3, wherein the control unit, when the document loading tray is stopped at the intermediate position, causes the lifting mechanism to lower the document loading tray to the lower limit position after a predetermined fourth waiting time has elapsed from the point at which the document discharged by the document discharge detection sensor no longer detects a document on the document discharge tray.

5. The document tray includes: a document placement table on which a document is placed; a cursor configured to be slidable on the upper surface of the document placing table in a document width direction perpendicular to the document conveying direction; an original width guide provided on the cursor and contacting the original placed on the original placement table in the original width direction to regulate the width of the original; a cursor movement detection sensor that detects movement of the cursor, 2. The document transport device according to claim 1, wherein when the cursor movement detection sensor detects movement of the cursor, the control unit does not start moving the document loading tray until a certain time has elapsed from the point at which the cursor movement detection sensor no longer detects movement of the cursor.

6. a document transport device according to any one of claims 1 to 5; An image forming apparatus comprising: an image forming unit that forms an image on a recording medium.

Images