Image reading device, image formation device, and image reading method

Abstract

To provide an image reading device, an image formation device, and an image reading method capable of suppressing the rise of a temperature of a motor with a simple arrangement.SOLUTION: An image formation device 100 comprises: an ADF 1 which conveys a sheet; an image reading unit 2 which reads an image on the sheet; a driving unit 27A which drives the ADF 1; and a switching processing unit 52 which switches an operation mode of the driving unit 27A between a driving mode in which the ADF 1 is driven and a cooling mode in which the driving unit 27A is cooled. The switching processing unit 52 switches the driving mode to the cooling mode when a total driving time of the driving unit 27A exceeds a first threshold.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an image reading apparatus for reading an image of a conveyed document, an image forming apparatus, and an image reading method. [Background technology]

[0002] There is known an image reading device that includes a conveying unit that conveys a document to be read and a reading unit that reads an image of the document. In the image reading device, the temperature of the motor (drive unit) that drives the conveying unit increases, so a function is provided to suppress the temperature increase of the motor (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5939818 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional technology predicts the motor temperature from the motor's rotation speed and controls the motor's drive based on the predicted temperature, which makes the process complicated because it requires constant monitoring of the motor's rotation speed.In particular, image reading devices that are designed to be lightweight and compact need to simplify each process, so there is a demand for a simpler configuration that can suppress motor temperature increases.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide an image reading apparatus, an image forming apparatus, and an image reading method that are capable of suppressing a temperature rise in a drive unit with a simple configuration. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided an image reading device including a conveying unit that conveys a sheet, a reading unit that reads an image on the sheet, a driving unit that drives the conveying unit, and a switching processing unit that switches an operation mode of the driving unit between a driving mode that drives the conveying unit and a cooling mode that cools the driving unit, wherein the switching processing unit switches to the cooling mode when a total driving time of the driving unit in the driving mode exceeds a first threshold.

[0007] An image forming apparatus according to another aspect of the present invention includes the image reading device described above and an image forming section that forms an image on the sheet.

[0008] According to another aspect of the present invention, an image reading method includes, in an image reading device including a conveying unit that conveys a sheet, a reading unit that reads an image on the sheet, and a driving unit that drives the conveying unit, a switching step of switching an operation mode of the driving unit between a driving mode that drives the conveying unit and a cooling mode that cools the driving unit, wherein the switching step switches to the cooling mode when a total driving time of the driving unit in the driving mode exceeds a first threshold. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an image reading device, an image forming device, and an image reading method that are capable of suppressing a temperature rise in a 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 diagram showing an example of driving state information stored in the image forming apparatus according to the embodiment of the present invention. [Figure 4]FIG. 4 is a timing chart showing the changes in the ON / OFF state of the image forming apparatus and the drive unit according to the embodiment of the present invention. [Figure 5] FIG. 5 is a graph showing the experimental results of the temperature change of the driving unit according to the embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing an example of driving state information stored in the image forming apparatus according to the embodiment of the present invention. [Figure 7] FIG. 7 is a diagram showing an example of driving state information stored in the image forming apparatus according to the embodiment of the present invention. [Figure 8] FIG. 8 is a diagram showing an example of driving state information stored in the image forming apparatus according to the embodiment of the present invention. [Figure 9] FIG. 9 is a flowchart showing an example of an operation mode switching process executed by the image forming apparatus according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the following embodiment is an example of 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 facsimile function, and a copy function. The image forming apparatus 100 is an example of the image forming apparatus of the present invention. The image forming apparatus of the present invention may also be a scanner, a facsimile machine, a copy machine, or the like.

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

[0015] The ADF 1 is a sheet conveying device that conveys a document to be read (an example of a sheet of the present invention). The ADF 1 executes a conveying process using a driving force supplied from a driving unit 27A in accordance with a control instruction from the control unit 7.

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

[0017] The image forming unit 3 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 or an EEPROM (registered trademark), a solid state drive (SSD), or a hard disk drive (HDD).

[0021] The control unit 7 performs overall control of the image forming apparatus 100. As shown in FIG. 1, the control unit 7 includes a CPU 11, a ROM 12, and a RAM 13. The CPU 11 is a processor that executes various types of arithmetic processing. The ROM 12 is a non-volatile storage device that stores in advance information such as control programs for causing the CPU 11 to execute various types of processing. The RAM 13 is a volatile or non-volatile storage device that is used as a temporary storage memory (work area) for the various types of processing executed by the CPU 11. In the control unit 7, the CPU 11 executes the various control programs that are pre-stored in the ROM 12. In this way, the control unit 7 performs overall control of the image forming apparatus 100.

[0022] [Configuration of ADF 1 and image reading unit 2] Next, the configuration of the ADF 1 and the image reading unit 2 will be described with reference to Figures 1 and 2. Here, Figure 2 is a cross-sectional view showing the configuration of the ADF 1 and the image reading unit 2. The ADF 1 and the image reading unit 2 are an example of the image reading device of the present invention.

[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 first conveying roller 30, a second conveying roller 31, a second ejection roller 32, and an ejection 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 first detection unit 21A detects whether or not a document is present on the document placement unit 21. For example, the first detection unit 21A is a reflective optical sensor provided on the document placement surface of the document placement unit 21.

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

[0027] The housing 22 houses rollers and the like used to transport the document. As shown in Fig. 2, a first transport path 22A and a second transport path 22D that guide the document are formed inside the housing 22. The second transport path 22D includes a curved portion 22C (see Fig. 2) that curves from the first transport path 22A and leads to the discharge unit 33. The curved portion 22C is curved at a curvature that allows the document to make a U-turn inside the housing 22.

[0028] In the ADF 1, a document placed on the document placement unit 21 is transported along a transport path that leads to the discharge unit 33 via the first transport path 22A, the curved portion 22C, and the second transport path 22D.

[0029] 2, an opening 22E is provided at the bottom of the housing 22. The opening 22E exposes a portion of the second transport path 22D to the outside. In the opening 22E, the second imaging unit 43 (see FIGS. 1 and 2) of the image reading unit 2 reads an image of the document transported by the ADF 1.

[0030] The pickup roller 23 is provided above the document placement unit 21. The pickup roller 23 comes into contact with the surface (top surface) of the uppermost document in the document stack lifted by the lift plate, and transports the document in the transport direction D1.

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

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

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

[0034] The first transport roller 30 is provided at the curved portion 22C of the second transport path 22D. The first transport roller 30 comes into contact with the document and transports the document downstream in the transport direction D1.

[0035] An opening 22E is formed in the second transport path 22D downstream in the transport direction D1 from the first transport roller 30. In the opening 22E, the image of the document passing through the opening 22E is read by the second imaging unit 43 (see FIGS. 1 and 2) of the image reading unit 2.

[0036] The second transport roller 31 is provided on the second transport path 22D downstream of the opening 22E in the transport direction D1. The second transport roller 31 comes into contact with the document transported by the first transport roller 30, and transports the document downstream in the transport direction D1.

[0037] The second discharge roller 32 is provided on the second conveying path 22D downstream of the second conveying roller 31 in the conveying direction D1. The second discharge roller 32 comes into contact with the document conveyed by the second conveying roller 31 and discharges the document to the discharge section 33. The discharge section 33 is loaded with the document discharged by the second 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, a second imaging unit 43, and a third imaging unit 44.

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

[0041] The second imaging unit 43 is provided below the first contact glass 411 and the second contact glass 412. The second imaging unit 43 is elongated in the depth direction of the paper in FIG. 2 and is provided so as to be movable in the left-right direction of the paper in FIG. 2. The second imaging unit 43 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 second imaging unit 43 includes a CIS (Contact Image Sensor) and a housing that houses the CIS. The second imaging unit 43 outputs an analog signal corresponding to the image read from the surface of the document. The analog signal output from the second imaging unit 43 is converted into a digital signal (image data) by an analog front-end circuit (not shown) and input to the control unit 7.

[0042] The first imaging unit 42 is provided downstream in the conveying direction D1 on the first conveying path 22A and upstream of the first discharge roller 28 in the conveying direction D1. The first imaging unit 42 reads an image of the surface of the document guided to the downstream side of the first conveying path 22A. Specifically, the first imaging unit 42 is a CIS. The first imaging unit 42 outputs an analog signal corresponding to the image read from the surface of the document. The analog signal output from the first imaging unit 42 is converted into a digital signal (image data) by the analog front-end circuit and input to the control unit 7.

[0043] The third imaging unit 44 is provided on the upstream side of the first conveying path 22A in the conveying direction D1 and downstream of the registration rollers 26 in the conveying direction D1. The third imaging unit 44 reads an image of the back side of the document conveyed by the registration rollers 26. Specifically, the third imaging unit 44 is a CIS. The third imaging unit 44 outputs an analog signal corresponding to the image read from the back side of the document. The analog signal output from the third imaging unit 44 is converted into a digital signal (image data) by the analog front-end circuit and input to the control unit 7.

[0044] The ADF 1 operates by receiving a driving force supplied from a driving unit 27A shown in Fig. 1. The driving unit 27A is a driving unit of the present invention, and is, for example, a motor. The driving unit 27A outputs a driving force to the ADF 1 in accordance with a control instruction from the control unit 7. The driving unit 27A is also set to an ON state or an OFF state in accordance with a control instruction from the control unit 7.

[0045] However, when the motor (drive unit 27A) is driven (operated) continuously for a long period of time, its temperature may rise, leading to a malfunction. Conventionally, a technique is known in which the motor temperature is predicted from the motor's rotational speed and the motor's drive is controlled based on the predicted temperature. However, this technique requires constant monitoring of the motor's rotational speed, which complicates the process. In particular, in image reading devices that are intended to be lightweight and compact, it is necessary to simplify each process, and therefore a simpler configuration is required to suppress the temperature rise of the motor. In contrast, the image forming apparatus 100 according to an embodiment of the present invention is capable of suppressing the temperature rise of the drive unit (motor) with a simple configuration, as described below.

[0046] [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 registration processing unit 51 and a switching processing unit 52.

[0047] Specifically, the ROM 12 pre-stores an operation mode switching program for causing the CPU 11 to execute an operation mode switching process (see FIG. 9) described below. The control unit 7 executes the operation mode switching program stored in the ROM 12, thereby functioning as a registration processing unit 51 and a switching processing unit 52. Here, an apparatus including the ADF 1, the image reading unit 2, and the control unit 7 is an example of the image reading apparatus of the present invention. Note that the present invention may also be realized by an apparatus including the ADF 1 and the control unit 7.

[0048] The operation mode switching 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 storage unit 6. The registration processing unit 51 and the switching processing unit 52 may be configured by electronic circuits such as an integrated circuit (ASIC).

[0049] The registration processing unit 51 registers the drive state of the drive unit 27A in the storage unit 6. Specifically, the registration processing unit 51 acquires the drive state, indicating whether the drive unit 27A is in the ON state or the OFF state, at a predetermined cycle (sampling time), and registers the drive state in the drive state information F1 (see FIG. 3) in the storage unit 6. In the example shown in FIG. 3, the sampling time is set to 10 seconds. The registration processing unit 51 acquires the drive state of the drive unit 27A every 10 seconds and registers it in the drive state information F1. Note that the drive unit 27A is in the ON state while the ADF 1 is operating (e.g., conveying a sheet) due to an image reading operation by the user, for example, and is in the OFF state while the image reading operation is not being performed.

[0050] 4, while the image forming apparatus 100 is powered on by being turned on or returning from a sleep mode, the drive unit 27A alternates between an ON state and an OFF state. While the image forming apparatus 100 is powered off, the drive unit 27A is in the OFF state.

[0051] Furthermore, the registration processing unit 51 registers, in the storage unit 6, the ON time when the image forming apparatus 100 is in the ON state, the OFF time when the image forming apparatus 100 is in the OFF state, the ON time when the drive unit 27A is in the ON state, and the OFF time when the drive unit 27A is in the OFF state. For example, the registration processing unit 51 updates the OFF time of the drive unit 27A when the image forming apparatus 100 is powered on or when it returns from sleep mode, and updates the ON time of the drive unit 27A when the image forming apparatus 100 is powered off or when it enters sleep mode.

[0052] The switching processor 52 alternately switches the operating mode of the drive unit 27A between a drive mode (normal mode) that drives the ADF 1 and a cooling mode that cools the drive unit 27A. Because the temperature of the drive unit 27A rises when it is continuously driven, the switching processor 52 switches to the cooling mode when a temperature rise is anticipated. For example, as shown in the experimental results of FIG. 5, it can be seen that the motor temperature rises to 90°C (design value) when the motor is continuously driven for 18.2 minutes. In this way, it is possible to determine the motor temperature from the total drive time (total ON time) of the motor within a predetermined period from the time the image forming apparatus 100 is powered on or returns from sleep mode.

[0053] Therefore, when the total driving time of the motor within a predetermined period exceeds a first threshold, the switching processing unit 52 switches the operation mode to the cooling mode. In the cooling mode, when the leading edge of a new document reaches a reading standby position (e.g., a position in front of the opening 22E), the document is stopped at that position for a certain period of time (e.g., 4 seconds) without being read, and after the certain period of time has elapsed, the image reading process is performed by the image reading unit 2. In other words, once the document is transported to the reading standby position, it waits there until permission is granted. In this way, in the cooling mode, a pause period is provided for each image reading, thereby temporarily stopping (turning off) the driving unit 27A and suppressing temperature rise.

[0054] In this way, the switching processing unit 52 switches the operation mode of the driving unit 27A, and drives the ADF 1 by causing the driving unit 27A to output a driving force in each of the driving mode and the cooling mode.

[0055] The switching processing unit 52 switches the drive mode to the cooling mode, for example, by using the configurations of Examples 1 to 3 described below.

[0056] In a first embodiment, the switching processing unit 52 calculates the total drive time as the total time during which the drive unit 27A is continuously in the ON state within the first predetermined period (determination period) after switching to the drive mode. For example, the switching processing unit 52 refers to the drive state information F1 (see FIG. 6) and calculates the total drive time by summing up the time during which the drive state is continuously in the ON state within the first 28 minutes (determination period) after switching to the drive mode. Then, the switching processing unit 52 switches to the cooling mode when the total drive time (continuous ON time) exceeds a first threshold value (e.g., 18.2 minutes).

[0057] In a second embodiment, the switching processing unit 52 calculates the total drive time as the total time that the drive unit 27A is in the ON state within the first predetermined period after switching to the drive mode. For example, the switching processing unit 52 refers to the drive state information F1 (see FIG. 6) and calculates the total drive time by adding up the time that the drive state is in the ON state within the first 28 minutes (determination period) after switching to the drive mode. Then, the switching processing unit 52 switches to the cooling mode when the total drive time exceeds a first threshold value (e.g., 18.2 minutes).

[0058] In a third embodiment, the switching processing unit 52 calculates the total drive time as the sum of the times during which the drive unit 27A is in the ON state within the immediately preceding predetermined period. For example, the switching processing unit 52 refers to the drive status information F1 (see FIG. 6) and calculates the total drive time by adding up the times during which the drive status is in the ON state within the immediately preceding 28 minutes (determination period). If the total drive time exceeds a first threshold (e.g., 18.2 minutes), the switching processing unit 52 switches to the cooling mode. If the total drive time is equal to or less than the first threshold, the switching processing unit 52 refers to the drive status information F1 (see FIG. 7) 10 seconds later and calculates the total drive time by adding up the times during which the drive status is in the ON state within the immediately preceding 28 minutes (determination period). If the total drive time exceeds a first threshold (e.g., 18.2 minutes), the switching processing unit 52 switches to the cooling mode. Similarly, if the total drive time is equal to or less than the first threshold, the switching processing unit 52 further refers to the drive status information F1 (see FIG. 8) from 10 seconds later, and calculates the total drive time by adding up the time during which the drive status is ON during the immediately preceding 28 minutes (determination period). Then, if the total drive time exceeds the first threshold (e.g., 18.2 minutes), the switching processing unit 52 switches to the cooling mode. Note that in the third embodiment, the switching processing unit 52 may calculate the total drive time as the sum of the time during which the drive unit 27A is continuously ON during the immediately preceding predetermined period.

[0059] In this way, the ON state and OFF state of the drive unit 27A are stored in the memory unit 6 (drive state information F1) at a predetermined cycle, and the switching processing unit 52 calculates the total drive time by referring to the drive state information F1. Furthermore, the switching processing unit 52 switches to the cooling mode when the total drive time of the drive unit 27A in the drive mode exceeds a first threshold. While the total drive time of the drive unit 27A is equal to or less than the first threshold, the switching processing unit 52 maintains the drive mode.

[0060] Furthermore, the switching processing unit 52 switches to the driving mode when the total driving time of the driving unit 27A becomes equal to or less than a second threshold value after transition to the cooling mode. Specifically, the switching processing unit 52 switches to the driving mode when the total time (total driving time) during which the driving unit 27A is in an ON state within a predetermined period (e.g., 28 minutes) in the cooling mode becomes equal to or less than a second threshold value (e.g., 16.2 minutes).

[0061] Furthermore, even if the total drive time exceeds a second threshold (e.g., 16.2 minutes) in the cooling mode, the switching processing unit 52 switches to the drive mode after a certain time (e.g., 10 minutes) has elapsed since the mode was switched to the cooling mode, because it is expected that the temperature of the drive unit 27A will drop sufficiently. In this case, the switching processing unit 52 registers the total drive time as 16.2 minutes.

[0062] In the above configuration, the times of the first threshold and the second threshold are not limited and can be set appropriately. For example, the first threshold and the second threshold can be set based on experimental results (see FIG. 5) according to the usage environment of the image forming apparatus 100.

[0063] In addition to the above-mentioned processes, the control unit 7 causes the image reading unit 2 to perform an image reading process and the image forming unit 3 to perform an image forming process. The control unit 7 also causes the operation display unit 5 to display various operation screens.

[0064] [Operation mode switching process] FIG. 9 shows an example of the procedure of the operation mode switching process executed by the control unit 7 of the image forming apparatus 100.

[0065] The present invention can be understood as an operation mode switching method (image reading method of the present invention) that executes one or more steps included in the operation mode switching process. One or more steps included in the operation mode switching process described here may be omitted as appropriate. The steps in the operation mode switching process may be executed in a different order as long as the same effects are achieved. While the description here takes as an example a case where the control unit 7 executes the steps in the operation mode switching process, in other embodiments, one or more processors may execute the steps in the operation mode switching process in a distributed manner.

[0066] The operation mode switching process is executed when the image forming apparatus 100 is turned on or when the image forming apparatus 100 returns from the sleep mode.

[0067] <Step S11> First, in step S11, the control unit 7 determines whether the sampling time (for example, 10 seconds) has elapsed. If the control unit 7 determines that the sampling time has elapsed (S11: Yes), the control unit 7 shifts the process to step S12. The control unit 7 waits until the sampling time has elapsed (S11: No).

[0068] Here, the control unit 7 checks the driving state of the driving unit 27A, for example, every second, and registers the ON time or OFF time of the driving unit 27A in the driving state information F1 (see FIG. 3) every 10 seconds.

[0069] <Step S12> In step S12, the control unit 7 acquires the driving state (ON time and OFF time) of the driving unit 27A for the immediately preceding predetermined period (for example, 28 minutes) from the driving state information F1 (see FIG. 3).

[0070] <Step S13> In step S13, the control unit 7 calculates the total drive time (total ON time) by adding up the time during which the drive state of the drive unit 27A is in the ON state. Note that the control unit 7 may calculate the total time during which the drive state of the drive unit 27A is continuously in the ON state as the total drive time.

[0071] <Step S14> In step S14, the control unit 7 determines whether the calculated total ON time exceeds a first threshold value (e.g., 18.2 minutes). If the control unit 7 determines that the total ON time exceeds 18.2 minutes (S14: Yes), the control unit 7 proceeds to step S15. On the other hand, if the control unit 7 determines that the total ON time does not exceed 18.2 minutes (S14: No), the control unit 7 returns the process to step S11.

[0072] <Step S15> In step S15, the control unit 7 switches the operation mode of the drive unit 27A to the cooling mode. When the operation mode of the drive unit 27A is set to the cooling mode, for example, when an image reading instruction is received, the document is stopped at a reading standby position (for example, a position in front of the opening 22E) for a certain period of time (for example, 4 seconds), and after the certain period of time has elapsed, the image reading process is executed by the image reading unit 2. In this way, in the cooling mode, the temperature of the drive unit 27A is lowered by providing a temporary suspension period for each image reading. Note that the control unit 7 updates the total ON time of the drive unit 27A after the certain period of time has elapsed. Step S15 is an example of a switching step of the present invention.

[0073] <Step S16> In step S16, the control unit 7 determines whether or not a sampling time (e.g., 10 seconds) has elapsed since the transition to the cooling mode. If the control unit 7 determines that the sampling time has elapsed (S16: Yes), the control unit 7 shifts the process to step S17. The control unit 7 waits until the sampling time has elapsed (S16: No).

[0074] <Step S17> In step S17, the control unit 7 acquires the driving state (ON time and OFF time) of the driving unit 27A for the immediately preceding predetermined period (for example, 28 minutes) from the driving state information F1 (see FIG. 3).

[0075] <Step S18> In step S18, the control unit 7 calculates the total ON time of the driving unit 27A.

[0076] <Step S19> In step S19, the control unit 7 determines whether the calculated total ON time is equal to or less than a second threshold value (e.g., 16.2 minutes). If the control unit 7 determines that the total ON time is equal to or less than 16.2 minutes (S19: Yes), the control unit 7 proceeds to step S21. In this case, the control unit 7 registers 16.2 minutes as the total ON time. On the other hand, if the control unit 7 determines that the total ON time exceeds 16.2 minutes (S19: No), the control unit 7 proceeds to step S20.

[0077] <Step S20> In step S20, the control unit 7 determines whether a certain time (e.g., 10 minutes) has elapsed since the transition to the cooling mode. If the control unit 7 determines that the certain time has elapsed (S20: Yes), it shifts the process to step S21. That is, even if the total ON time in the cooling mode exceeds a second threshold (e.g., 16.2 minutes), the control unit 7 shifts the process to step S21 if a certain time (e.g., 10 minutes) has elapsed since the transition to the cooling mode (S20: Yes). In this case, the control unit 7 registers 16.2 minutes as the total ON time. On the other hand, if the control unit 7 determines that the certain time has not elapsed (S20: No), it returns the process to step S16.

[0078] <Step S21> In step S21, the control unit 7 switches the operation mode of the drive unit 27A to the drive mode. When the operation mode of the drive unit 27A is set to the drive mode, for example, when an image reading instruction is received, a normal reading process is executed without temporarily stopping the document at the reading standby position. Step S21 is an example of a switching step of the present invention.

[0079] <Step S22> In step S22, the control unit 7 determines whether the image forming apparatus 100 is powered off or has entered sleep mode. If the image forming apparatus 100 is powered off or has entered sleep mode (S22: Yes), the control unit 7 ends the operation mode switching process. On the other hand, if the image forming apparatus 100 is powered on or has not entered sleep mode (S22: No), the control unit 7 returns the process to step S11.

[0080] As described above, the control unit 7 repeatedly executes the operation mode switching process each time the image forming apparatus 100 is powered on or returns from sleep mode. The above-described operation mode switching process is merely an example, and the content and order of the processes can be changed as appropriate. For example, the control unit 7 resets the total ON time after the total ON time determination process (S14, S19). The control unit 7 also updates the total OFF time of the drive unit 27A at the power-on point and sleep return point shown in FIG. 4, and updates the total ON time of the drive unit 27A at the power-off point and sleep entry point. The control unit 7 also registers the time the image forming apparatus 100 is powered on, the time the drive unit 27A is powered on, the operation mode status of the drive unit 27A, and the power status of the image forming apparatus 100 every predetermined period (e.g., 28 minutes).

[0081] As described above, when the drive unit 27A (motor) is set to the drive mode, the image forming apparatus 100 switches to the cooling mode if the total drive time (total ON time) of the drive unit 27A exceeds the first threshold. For example, the control unit 7 switches to the cooling mode if the total drive time exceeds the first threshold (e.g., 18.2 minutes) within a 28-minute period (determination period) in the drive mode. In this way, the control unit 7 switches to the cooling mode when the ON state of the drive unit 27A reaches a predetermined time, thereby suppressing a temperature rise of the drive unit 27A. With the above configuration, a temperature rise of the drive unit 27A can be suppressed without using a cooling fan, a temperature sensor, or the like, and the drive unit 27A can be protected from overheating. Therefore, a temperature rise of the drive unit 27A can be suppressed with a simple configuration. This also reduces the cost of the image forming apparatus 100.

[0082] Furthermore, the control unit 7 is configured to switch to the driving mode when the total driving time of the driving unit 27A becomes less than a second threshold after the cooling mode is entered, thereby quickly returning to the normal driving mode when the temperature of the driving unit 27A drops, thereby preventing a decrease in the efficiency of the image reading process.

[0083] [Disclosure Note] The following will provide an outline of the disclosure 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.

[0084] <Appendix 1> a conveying unit that conveys a sheet; a reading unit that reads an image on the sheet; a drive unit that drives the conveying unit; a switching processing unit that switches the operation mode of the drive unit between a drive mode that drives the transport unit and a cooling mode that cools the drive unit; Equipped with the switching processing unit switches to the cooling mode when a total driving time of the driving unit in the driving mode exceeds a first threshold value. Image reading device.

[0085] <Appendix 2> the switching processing unit switches to the driving mode when a total driving time of the driving unit after transitioning to the cooling mode becomes less than a second threshold value. 2. An image reading device according to claim 1.

[0086] <Appendix 3> the switching processing unit calculates, in the drive mode, the total drive time as the total time during which the drive unit is continuously in an ON state within a predetermined period; 3. An image reading device according to claim 1 or 2.

[0087] <Appendix 4> the switching processing unit calculates, in the drive mode, the total drive time as the total time during which the drive unit is in an ON state within a predetermined period; 3. An image reading device according to claim 1 or 2.

[0088] <Appendix 5> the switching processing unit calculates, in the drive mode, the total drive time as the sum of the times during which the drive unit is in an ON state within a most recent predetermined period; 3. An image reading device according to claim 1 or 2.

[0089] <Appendix 6> In the cooling mode, the sheet is temporarily stopped before the reading unit reads the image. 6. An image reading device according to any one of appendices 1 to 5.

[0090] <Appendix 7> storing the ON and OFF states of the drive unit in a storage unit at a predetermined cycle; the switching processing unit calculates the total drive time by referring to the storage unit; 7. An image reading device according to any one of appendices 1 to 6.

[0091] <Appendix 8> An image forming apparatus comprising: the image reading device according to any one of Supplementary Notes 1 to 7; and an image forming section that forms an image on the sheet. [Explanation of symbols]

[0092] 100: Image forming device 2: Image reading unit 3: Image forming unit 4:Paper feed section 5: Operation display section 6: Storage section 7: Control section 27A: Drive unit (motor) 51: Registration processing unit 52: Switching processing section F1: Driving status information

Claims

1. a conveying unit that conveys a sheet; a reading unit that reads an image on the sheet; a drive unit that drives the conveying unit; a switching processing unit that switches the operation mode of the drive unit between a drive mode that drives the transport unit and a cooling mode that cools the drive unit; Equipped with the switching processing unit switches to the cooling mode when a total driving time of the driving unit in the driving mode exceeds a first threshold value. Image reading device.

2. the switching processing unit switches to the driving mode when the total driving time of the driving unit becomes less than a second threshold value after the mode is switched to the cooling mode.

2. The image reading device according to claim 1.

3. the switching processing unit calculates, in the drive mode, the total drive time as the total time during which the drive unit is continuously in an ON state within a predetermined period; 2. The image reading device according to claim 1.

4. the switching processing unit calculates, in the drive mode, a total time during which the drive unit is in an ON state within a predetermined period as the total drive time; 2. The image reading device according to claim 1.

5. the switching processing unit calculates, in the drive mode, the total drive time as the sum of the time during which the drive unit is in an ON state within a most recent predetermined period; 2. The image reading device according to claim 1.

6. In the cooling mode, the sheet is temporarily stopped before the reading unit reads the image.

2. The image reading device according to claim 1.

7. storing the ON and OFF states of the drive unit in a storage unit at a predetermined cycle; the switching processing unit calculates the total drive time by referring to the storage unit; 2. The image reading device according to claim 1.

8. 8. An image forming apparatus comprising: the image reading device according to claim 1; and an image forming section that forms an image on the sheet.

9. In an image reading device including a conveying unit that conveys a sheet, a reading unit that reads an image on the sheet, and a driving unit that drives the conveying unit, the method includes a switching step of switching an operation mode of the driving unit between a driving mode that drives the conveying unit and a cooling mode that cools the driving unit, In the switching step, the mode is switched to the cooling mode when a total driving time of the driving unit in the driving mode exceeds a first threshold value. Image reading method.

Images