Sheet conveying device, image processing apparatus, and drive control method

Abstract

To provide a sheet conveying device, an image processing apparatus, and a drive control method that can prevent an increase in the temperature of a motor with a simple configuration.SOLUTION: An image forming apparatus comprises: a motor that is used for conveyance of a sheet; a first determination processing unit that, every time determination timing arrives during drive of the motor, determines whether the total of drive time of the motor in a determination period Z10 until the arrival of the determination timing exceeds first time X1; and a first restriction processing unit that restricts the drive of the motor when the first determination processing unit determines that the total exceeds the first time X1.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] There is known an image processing apparatus that includes an image reading unit that reads an image of a document and a document transport unit that transports the document whose image is to be read by the image reading unit. Also, there is known an image processing apparatus that can suppress a temperature rise of a motor that drives the document transport unit (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-155009 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the image processing device according to the related art, the drive of the motor is controlled based on the predicted temperature of the motor, which requires a configuration for predicting the temperature of the motor, and therefore complicates the configuration for suppressing the temperature rise of the motor.

[0005] An object of the present invention is to provide a sheet conveying device, an image processing device, and a drive control method that can suppress a temperature rise in a motor with a simple configuration. [Means for solving the problem]

[0006] According to one aspect of the present invention, a sheet conveying device includes a motor, a first determination processor, a first restriction processor, a second determination processor, and a second restriction processor. The motor is used to convey a sheet. Each time a predetermined determination timing occurs while the motor is being driven, the first determination processor determines whether a total drive time of the motor during a predetermined determination period up to the arrival of the determination timing exceeds a predetermined first time. The first restriction processor limits drive of the motor when the first determination processor determines that the total exceeds the first time. The second determination processor determines whether an elapsed time from a start of drive of the motor immediately prior to a reference time at which drive of the motor is started exceeds the length of the determination period. The second restriction processor limits drive of the motor when the second determination processor determines that the elapsed time exceeds the length of the determination period and when the drive time of the motor from the reference time exceeds a second time shorter than the first time.

[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] A drive control method according to another aspect of the present invention is executed in a sheet conveying device including a motor used for conveying sheets, and includes a first determination step, a first limiting step, a second determination step, and a second limiting step. In the first determination step, each time a predetermined determination timing occurs while the motor is being driven, it is determined whether a total drive time of the motor during a predetermined determination period up to the arrival of the determination timing exceeds a predetermined first time. In the first limiting step, if it is determined in the first determination step that the total exceeds the first time, drive of the motor is limited. In the second determination step, it is determined whether an elapsed time from a start of drive of the motor immediately preceding a reference time at which drive of the motor is started exceeds the length of the determination period. In the second limiting step, if it is determined in the second determination step that the elapsed time exceeds the length of the determination period and if the drive time of the motor from the reference time exceeds a second time shorter than the first time, drive of the motor is limited. [Effects of the Invention]

[0009] According to the present invention, it is possible to suppress the temperature rise of the motor with a simple configuration. [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 timing chart showing an example of the change over time in the driving state of the motor of the image forming apparatus according to the embodiment of the present invention. [Figure 4] FIG. 4 is a timing chart showing an example of the change over time in the driving state of the motor of the image forming apparatus according to the embodiment of the present invention. [Figure 5]FIG. 5 is a timing chart showing an example of the change over time in the driving state of the motor of the image forming apparatus according to the embodiment of the present invention. [Figure 6] FIG. 6 is a flowchart showing an example of a drive control process executed in 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 a specific embodiment 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 fax 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 printer, 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 to be read (an example of a sheet of the present invention). The ADF 1 performs a conveying process using a driving force supplied from a motor 27A in accordance with a control instruction from the control unit 7.

[0016] The image reading unit 2 reads an image of a document conveyed by the ADF 1. The image reading unit 2 also reads an image of a document placed on a document table 41 (see FIG. 2).

[0017] The image forming unit 3 forms an image by electrophotography on a sheet supplied from the paper feed unit 4. 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, 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 motor 27A, a first conveying roller 30, a second conveying roller 31, a discharge roller 32, and a discharge section 33.

[0024] A document to be transported is placed on the document placement unit 21. In the ADF 1, the document placed on the document placement unit 21 is transported in a transport direction D1 shown in FIG.

[0025] 1 is provided in the document placement unit 21. The detection unit 21A detects whether or not a document is present on the document placement unit 21. For example, the 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 transport path 22A for guiding the document is formed inside the housing 22.

[0028] In the ADF 1, a document placed on the document placement unit 21 is conveyed to the discharge unit 33 through the conveyance path 22A.

[0029] 2, an opening 22B is provided at the bottom of the housing 22. The opening 22B exposes a portion of the transport path 22A to the outside. In the opening 22B, the first imaging unit 42 (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 in the 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 conveyance path 22A downstream in the conveyance direction D1 of the paper feed belt 24. The registration rollers 26 come into contact with the document conveyed by the paper feed belt 24 and convey the document downstream in the conveyance direction D1.

[0034] The first transport roller 30 is provided on the transport path 22A downstream in the transport direction D1 from the registration roller 26. The first transport roller 30 comes into contact with the document and transports the document downstream in the transport direction D1.

[0035] An opening 22B is formed in the conveying path 22A downstream in the conveying direction D1 from the first conveying roller 30. In the opening 22B, the image of the document passing through the opening 22B is read by the first imaging unit 42 (see FIGS. 1 and 2) of the image reading unit 2.

[0036] The second transport roller 31 is provided downstream of the opening 22B in the transport path 22A 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.

[0037] The discharge roller 32 is provided on the conveyance path 22A downstream of the second conveyance roller 31 in the conveyance direction D1. The discharge roller 32 comes into contact with the document conveyed by the second conveyance roller 31 and discharges the document to the discharge section 33. The discharge section 33 is loaded with the document discharged by the discharge roller 32.

[0038] As shown in FIGS. 1 and 2, the image reading unit 2 includes a document table 41, a first imaging unit 42, and a second imaging unit 43.

[0039] 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 covers one side of a document placed on first contact glass 411 of document table 41.

[0040] 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 first imaging unit 42, is placed on the first contact glass 411. The second contact glass 412 and the guide member 413 face the opening 22B of the housing 22 and form part of the transport path 22A when the ADF 1 is closed relative to the document table 41. The second contact glass 412 transmits light emitted from the first imaging unit 42 toward the opening 22B 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.

[0041] The first imaging unit 42 is provided below the first contact glass 411 and the second contact glass 412. The first imaging unit 42 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 first imaging unit 42 reads an image of the surface of a document transported by the ADF 1 while being disposed below the second contact glass 412. Specifically, the first imaging unit 42 includes a CIS (Contact Image Sensor) and a housing that houses the CIS. The first imaging unit 42 outputs an analog signal corresponding to the image read from the surface of the document. The analog signal output from the first imaging unit 42 is converted into a digital signal (image data) by an analog front-end circuit (not shown) and input to the control unit 7.

[0042] The second imaging unit 43 is provided on the conveying path 22A downstream of the registration rollers 26 in the conveying direction D1 and upstream of the first conveying rollers 30 in the conveying direction D1. The second imaging unit 43 reads an image of the back side of the document conveyed by the registration rollers 26. Specifically, the second imaging unit 43 is a CIS. The second imaging unit 43 outputs an analog signal corresponding to the image read from the back side of the document. The analog signal output from the second imaging unit 43 is converted into a digital signal (image data) by the analog front-end circuit and input to the control unit 7.

[0043] The ADF 1 operates by receiving a driving force supplied from a motor 27A shown in Fig. 1. That is, the motor 27A is used to transport sheets. The motor 27A outputs a driving force to the ADF 1 in accordance with a control instruction from the control unit 7. The motor 27A is also set to an ON state or an OFF state in accordance with a control instruction from the control unit 7.

[0044] However, if the motor 27A is driven (operated) continuously for a long period of time, the temperature of the motor 27A may rise, which may lead to a breakdown. Here, an image processing device capable of suppressing the temperature rise of the motor 27A is known as related art.

[0045] However, in the image processing device according to the related art, the driving of the motor 27A is controlled based on the predicted temperature of the motor 27A, which requires a configuration for predicting the temperature of the motor 27A, which complicates the configuration for suppressing the temperature rise of the motor 27A.

[0046] In contrast to this, in the image forming apparatus 100 according to the embodiment of the present invention, it is possible to suppress the temperature rise of the motor 27A with a simple configuration, as will be described below.

[0047] [Configuration of control unit 7] Next, the configuration of the control unit 7 will be described in more detail with reference to Fig. 1. As shown in Fig. 1, the control unit 7 includes a recording processing unit 51, a first determination processing unit 52, a first restriction processing unit 53, a second determination processing unit 54, and a second restriction processing unit 55.

[0048] Specifically, a drive control program for causing the CPU 11 to execute a drive control process (see FIG. 6) described below is stored in advance in the ROM 12. The control unit 7 functions as each of the above-mentioned processing units by executing the drive control program stored in the ROM 12. Here, an apparatus including the ADF 1 and the control unit 7 is an example of a sheet conveying apparatus of the present invention.

[0049] The drive control program may be recorded on a computer-readable recording medium such as a CD, DVD, or flash memory, and may be read from the recording medium and stored in a storage device such as the memory unit 6. Some or all of the processing units included in the control unit 7 may be configured with electronic circuits. The operation control program may also be a program for causing multiple processors to function as the processing units included in the control unit 7.

[0050] The recording processing unit 51 records the change in the driving state of the motor 27A.

[0051] For example, when the driving of the motor 27A starts (when the state of the motor 27A changes from OFF to ON), the recording processing unit 51 records the driving start time of the motor 27A. Specifically, the recording processing unit 51 stores information indicating the driving start time of the motor 27A in a predetermined storage area in the storage unit 6.

[0052] Furthermore, when the driving of the motor 27A is terminated (when the motor 27A changes from an ON state to an OFF state), the recording processing unit 51 records the driving end time of the motor 27A. Specifically, the recording processing unit 51 stores information indicating the driving end time of the motor 27A in the storage area of ​​the storage unit 6.

[0053] The recording processing unit 51 may determine the current driving state of the motor 27A at a predetermined recording cycle, and store information indicating the determination result in the storage area of ​​the storage unit 6.

[0054] Each time a predetermined determination timing occurs while motor 27A is being driven, first determination processing unit 52 determines whether the total drive time of motor 27A during a predetermined determination period Z10 (see FIG. 3) up to the arrival of the determination timing exceeds a predetermined first time X1 (see FIG. 3). Note that in FIG. 3, determination period Z10 is indicated by a two-dot chain line.

[0055] For example, the determination timing is a timing that occurs every 10 seconds from the start of driving of the motor 27A. Note that the determination timing may be a timing that occurs periodically or irregularly while the motor 27A is being driven.

[0056] Furthermore, the determination period Z10 has a length X10 (see FIG. 3) of 28 minutes.

[0057] The first time X1 is 18.2 minutes.

[0058] For example, when the determination timing arrives, first determination processing unit 52 acquires the total drive time of motor 27A during determination period Z10 based on the recording result by recording processing unit 51. Then, first determination processing unit 52 determines whether the acquired total drive time of motor 27A exceeds first time X1.

[0059] For example, suppose that motor 27A has been driven as shown in Fig. 3 by determination timing T12 shown in Fig. 3. In this case, first determination processing unit 52 acquires the elapsed time from drive start timing T11 to determination timing T12 as the total drive time of motor 27A during determination period Z10. Then, first determination processing unit 52 determines that the acquired total drive time of motor 27A exceeds first time X1.

[0060] When the continuous driving time of motor 27A exceeds 18.2 minutes, motor 27A transitions to an abnormal state in which the temperature of motor 27A exceeds a predetermined upper limit temperature. Driving motor 27A in this abnormal state increases the risk of motor 27A malfunction. Driving motor 27A in this abnormal state can also cause problems, such as motor 27A catching fire or components around motor 27A deforming due to heat generated by motor 27A. For this reason, in image forming apparatus 100, first time period X1 is set to 18.2 minutes.

[0061] First restriction processing unit 53 restricts the driving of motor 27A when first determination processing unit 52 determines that the total driving time of motor 27A in determination period Z10 exceeds first time X1.

[0062] For example, the first restriction processing unit 53 switches the document transport mode of the ADF 1 from the normal transport mode to the low-speed transport mode, which transports fewer documents per minute than the normal transport mode. In the normal transport mode, multiple documents are transported continuously without stopping the motor 27A. On the other hand, in the low-speed transport mode, the motor 27A is stopped for a certain period of time each time one document is transported. In other words, the motor 27A is driven intermittently (see FIG. 3). For example, in the low-speed transport mode, the motor 27A is stopped for four seconds each time the document reaches the first transport roller 30 (see FIG. 2). This suppresses a temperature rise in the motor 27A due to continuous driving of the motor 27A.

[0063] Furthermore, when the transport mode has transitioned to the low-speed transport mode, the first restriction processing unit 53 determines, each time the determination timing arrives, whether the total drive time of the motor 27A during the determination period Z10 is equal to or shorter than a third time (e.g., 16.2 minutes) that is shorter than the first time X1. When the first restriction processing unit 53 determines that the total drive time of the motor 27A during the determination period Z10 is equal to or shorter than the third time, the first restriction processing unit 53 switches the transport mode from the low-speed transport mode to the normal transport mode. In other words, the first restriction processing unit 53 releases the drive restriction on the motor 27A. When the low-speed transport mode has continued for more than a predetermined time (e.g., 10 minutes), the first restriction processing unit 53 switches the transport mode from the low-speed transport mode to the normal transport mode.

[0064] In addition, when the first judgment processing unit 52 determines that the total driving time of the motor 27A during the judgment period Z10 exceeds the first time X1, the first restriction processing unit 53 may stop the motor 27A for a predetermined time instead of switching the conveying mode to the low-speed conveying mode.

[0065] Now, suppose that motor 27A is driven as shown in Fig. 4 by drive start timing T23 shown in Fig. 4. In this case, if the drive time of motor 27A from drive start timing T23 included in determination period Z10 increases, the drive time of motor 27A until drive end timing T22 included in determination period Z10 decreases by the same amount as the increase. Therefore, drive of motor 27A is not restricted until the continuous drive time of motor 27A from drive start timing T23 exceeds first time X1.

[0066] However, at drive start timing T23, motor 27A may not have cooled down to the temperature of the installation environment of image forming apparatus 100. In other words, heat generated during the previous drive period of motor 27A (the period from drive start timing T21 to drive end timing T22) may remain. In this case, if the drive of motor 27A is not restricted until the continuous drive time of motor 27A from drive start timing T23 exceeds first time X1, motor 27A will enter the abnormal state before the continuous drive time of motor 27A from drive start timing T23 reaches first time X1, increasing the risk of failure of motor 27A.

[0067] In contrast, in the image forming apparatus 100 according to the embodiment of the present invention, the risk of failure of the motor 27A can be reduced, as will be described below.

[0068] The second determination processor 54 determines whether the time elapsed from the start of driving of the motor 27A immediately before the reference time at which the driving of the motor 27A starts exceeds the length X10 of the determination period Z10. The reference time is the start of driving of the motor 27A.

[0069] For example, suppose that motor 27A is driven as shown in Fig. 4 up to drive start timing T23 shown in Fig. 4. In this case, second determination processing unit 54 determines that the elapsed time from the drive start time of motor 27A immediately prior to drive start timing T23, which is the reference time (the elapsed time from drive start timing T21 to drive start timing T23) exceeds length X10 of determination period Z10.

[0070] The second restriction processing unit 55 restricts the driving of the motor 27A when the second judgment processing unit 54 judges that the elapsed time from the start of driving of the motor 27A immediately before the reference time exceeds the length X10 of the judgment period Z10, and when the driving time of the motor 27A from the reference time exceeds a second time X2 (see Figure 5) that is shorter than the first time X1.

[0071] For example, the second time X2 is set based on the first time X1 and the difference between the length X10 of the determination period Z10 and the time the motor 27A was stopped until the reference time. For example, the second time X2 is a time obtained by subtracting the difference between the length X10 of the determination period Z10 and the time the motor 27A was stopped until the reference time (the elapsed time from the drive end timing T22 to the drive start timing T23) from the first time X1 (see FIG. 4). By setting the second time X2 in this manner, it is possible to set the second time X2 taking into consideration the elapsed time since the drive of the motor 27A ended immediately before the reference time (the natural cooling time of the motor 27A).

[0072] The second time X2 may be a time obtained by multiplying the first time X1 by a predetermined coefficient (for example, 0.5).

[0073] [Drive control processing] 6, the drive control method of the present invention will be described below along with an example of the procedure of the drive control process executed by the control unit 7 in the image forming apparatus 100. Here, steps S11, S12, etc. represent the numbers of the process procedures (steps) executed by the control unit 7. Note that the drive control process is executed together with the conveyance process when the conveyance of the document by the ADF 1 (the conveyance process) is started.

[0074] The change in the driving state of the motor 27A during the execution of the transport process is recorded by the recording processing unit 51 of the control unit .

[0075] <Step S11> First, in step S11, the control unit 7 executes a second determination process to determine whether or not the elapsed time from the start of driving of the motor 27A immediately preceding the reference time at which driving of the motor 27A is first started during execution of the transport process exceeds the length X10 of the determination period Z10. The process of step S11 is an example of the second determination step of the present invention, and is executed by the second determination processing unit 54 of the control unit 7.

[0076] Specifically, the control unit 7 executes the second determination process based on the recording result of the recording processing unit 51 regarding the change in the driving state of the motor 27A.

[0077] <Step S12> In step S12, the control unit 7 branches the process depending on the result of the second determination process. Specifically, if the control unit 7 determines in the second determination process that the elapsed time from the start of drive of the motor 27A immediately before the reference time exceeds the length X10 of the determination period Z10 (Yes in S12), the control unit 7 shifts the process to step S21. On the other hand, if the control unit 7 determines in the second determination process that the elapsed time from the start of drive of the motor 27A immediately before the reference time does not exceed the length X10 of the determination period Z10 (No in S12), the control unit 7 shifts the process to step S13.

[0078] <Step S13> In step S13, the control unit 7 determines whether the transport process has been completed.

[0079] Here, if the control unit 7 determines that the transport process has ended (Yes in S13), it ends the drive control process. If the transport process has not ended (No in S13), the control unit 7 shifts the process to step S14.

[0080] <Step S14> In step S14, the control unit 7 determines whether or not the determination timing has arrived.

[0081] Specifically, the control unit 7 determines that the determination timing has arrived when 10 seconds have passed since the arrival of the last determination timing (or the reference time).

[0082] Here, if the control unit 7 determines that the determination timing has arrived (Yes in S14), it shifts the process to step S15. On the other hand, if the determination timing has not arrived (No in S14), it shifts the process to step S13.

[0083] <Step S15> In step S15, the control unit 7 executes a first determination process to determine whether the total driving time of the motor 27A during the determination period Z10 up to the arrival of the final determination timing exceeds the first time X1. The process of step S15 is an example of the first determination step of the present invention, and is executed by the first determination processing unit 52 of the control unit 7.

[0084] Specifically, the control unit 7 executes the first determination process based on the recording result of the recording processing unit 51 regarding the change in the driving state of the motor 27A.

[0085] <Step S16> In step S16, the control unit 7 branches the process depending on the result of the first determination process. Specifically, if the control unit 7 determines in the first determination process that the total driving time of the motor 27A in the determination period Z10 until the arrival of the final determination timing exceeds the first time X1 (Yes in S16), the control unit 7 shifts the process to step S17. On the other hand, if the control unit 7 determines in the first determination process that the total driving time of the motor 27A in the determination period Z10 until the arrival of the final determination timing does not exceed the first time X1 (No in S16), the control unit 7 shifts the process to step S13.

[0086] <Step S17> In step S17, the control unit 7 limits the driving of the motor 27A. The process of step S17 is an example of a first limiting step of the present invention, and is executed by the first limiting processing unit 53 of the control unit 7.

[0087] Specifically, the control unit 7 switches the transport mode of the document in the ADF 1 from the normal transport mode to the low-speed transport mode.

[0088] <Step S18> In step S18, the control unit 7 determines whether or not the transport process has been completed.

[0089] Here, if the control unit 7 determines that the transport process has ended (Yes in S18), it ends the drive control process. If the transport process has not ended (No in S18), the control unit 7 waits for the transport process to end in step S18.

[0090] In addition, while waiting for the completion of the conveying process, the control unit 7 releases the drive restriction on the motor 27A when the total driving time of the motor 27A during the judgment period Z10 decreases to the third time or less, or when the low-speed conveying mode continues for more than a predetermined time.

[0091] <Step S21> In step S21, the control unit 7 determines whether or not the transport process has been completed.

[0092] Here, if the control unit 7 determines that the transport process has ended (Yes in S21), it ends the drive control process. If the transport process has not ended (No in S21), the control unit 7 shifts the process to step S22.

[0093] <Step S22> In step S22, the control unit 7 determines whether or not the driving time of the motor 27A from the reference time exceeds the second time X2.

[0094] Here, if the control unit 7 determines that the driving time of the motor 27A from the reference time exceeds the second time X2 (Yes in S22), the control unit 7 shifts the process to step S23. On the other hand, if the driving time of the motor 27A from the reference time does not exceed the second time X2 (No in S22), the control unit 7 shifts the process to step S21.

[0095] <Step S23> In step S23, the control unit 7 limits the driving of the motor 27A, similarly to step S17. The process of step S23 is an example of a second limiting step of the present invention, and is executed by the second limiting processing unit 55 of the control unit 7.

[0096] <Step S24> In step S24, the control unit 7 determines whether or not the transport process has been completed.

[0097] Here, if the control unit 7 determines that the transport process has ended (Yes in S24), it ends the drive control process. If the transport process has not ended (No in S24), the control unit 7 waits for the transport process to end in step S24.

[0098] In addition, while waiting for the completion of the conveying process, the control unit 7 releases the drive restriction on the motor 27A when the total driving time of the motor 27A during the judgment period Z10 decreases to the third time or less, or when the low-speed conveying mode continues for more than a predetermined time.

[0099] In this way, in image forming apparatus 100, the driving of motor 27A is controlled based on the total driving time of motor 27A during determination period Z10. This makes it possible to suppress a rise in the temperature of motor 27A with a simpler configuration than a configuration in which the driving of motor 27A is controlled based on the predicted temperature of motor 27A.

[0100] [Notes on the Invention] The following is a summary of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0101] <Appendix 1> a first restriction processing unit that restricts the driving of the motor when the first determination processing unit determines that the total driving time of the motor during a predetermined determination period up to the arrival of a predetermined determination timing exceeds a predetermined first time; a second determination processing unit that restricts the driving of the motor when the first determination processing unit determines that the total driving time exceeds the first time; a second determination processing unit that restricts the driving of the motor when the elapsed time from the start of driving of the motor immediately before the reference time when driving of the motor starts exceeds the length of the determination period; and a second restriction processing unit that restricts the driving of the motor when the second determination processing unit determines that the elapsed time exceeds the length of the determination period and when the driving time of the motor from the reference time exceeds a second time that is shorter than the first time.

[0102] <Appendix 2> 2. The sheet conveying device according to claim 1, wherein the second time is set based on the difference between the length of the determination period and the stop time of the motor until the reference time, and the first time.

[0103] <Appendix 3> 3. An image processing apparatus comprising: the sheet conveying device according to claim 1 or 2; and an image reading unit that reads an image on a sheet conveyed by the sheet conveying device.

[0104] <Appendix 4> A drive control method executed in a sheet conveying device equipped with a motor used to convey sheets, the drive control method including: a first determination step for determining, each time a predetermined determination timing arrives while the motor is being driven, whether a total drive time of the motor during a predetermined determination period up to the arrival of the determination timing exceeds a predetermined first time; a first restriction step for restricting drive of the motor if it is determined by the first determination step that the total exceeds the first time; a second determination step for determining whether an elapsed time from the start of drive of the motor immediately before a reference time at which drive of the motor is started exceeds the length of the determination period; and a second restriction step for restricting drive of the motor if it is determined by the second determination step that the elapsed time exceeds the length of the determination period and if the drive time of the motor from the reference time exceeds a second time that is shorter than the first time. [Explanation of symbols]

[0105] 1:ADF 2: Image reading unit 3: Image forming unit 4:Paper feed section 5: Operation display section 6: Storage section 7: Control section 27A: Motor 51: Recording processing unit 52: First determination processing unit 53: First restriction processing unit 54: Second determination processing unit 55: Second restriction processing unit 100: Image forming device

Claims

1. a motor used to transport the sheet; a first determination processing unit that determines, each time a predetermined determination timing arrives while the motor is being driven, whether or not a total drive time of the motor during a predetermined determination period up to the arrival of the determination timing exceeds a predetermined first time; a first restriction processing unit that restricts driving of the motor when the first determination processing unit determines that the total exceeds the first time period; a second determination processing unit that determines whether or not a time that has elapsed from a time when the motor starts to be driven immediately before a reference time when the motor starts to be driven exceeds a length of the determination period; a second restriction processing unit that restricts driving of the motor when the second determination processing unit determines that the elapsed time exceeds the length of the determination period and when a driving time of the motor from the reference time exceeds a second time that is shorter than the first time; A sheet conveying device comprising:

2. the second time period is set based on a difference between the length of the determination period and the stop time of the motor until the reference time, and the first time period. The sheet transport device according to claim 1 .

3. The sheet conveying device according to claim 1 or 2; an image reading unit that reads an image on a sheet conveyed by the sheet conveying device; An image processing device comprising:

4. A drive control method executed in a sheet conveying device including a motor used for conveying a sheet, comprising: a first determination step of determining, each time a predetermined determination timing arrives while the motor is being driven, whether or not a total drive time of the motor during a predetermined determination period up to the arrival of the determination timing exceeds a predetermined first time; a first limiting step of limiting driving of the motor when it is determined in the first determining step that the total exceeds the first time; a second determination step of determining whether or not the elapsed time from the start of driving of the motor immediately before the reference time at which the driving of the motor is started exceeds the length of the determination period; a second limiting step of limiting driving of the motor when it is determined in the second determining step that the elapsed time exceeds the length of the determination period and when the driving time of the motor from the reference time exceeds a second time that is shorter than the first time; A drive control method including:

Images