Sheet feeding device and image forming device

Abstract

To provide a sheet feeding device and an image forming device capable of preventing abnormal overheat at a heating part as well as suppressing adherence of a sheet in a sheet accommodation section even when the sheet accommodation section is pulled out from a device body during sheet feeding operation.SOLUTION: A heat control section 95 drives a heater 36 to carry out heating control with the heater 36 during sheet feeding operation. An air quantity control section 96 drives a blowing fan 35 to carry out blowing control with the blowing fan 35 during the sheet feeding operation. When a sheet accommodation section 41 is pulled out during the sheet feeding operation, the heat control section 95 stops the heater 36, and the air quantity control section 96 does not stop the blowing fan 35 to continuously drive the blowing fan 35 only for a setup time.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a sheet feeding device and an image forming apparatus equipped with the sheet feeding device. [Background technology]

[0002] An electrophotographic image forming apparatus includes a sheet feeding device that feeds sheets to an image forming unit. The sheet feeding device picks up one sheet from a plurality of sheets stacked on a tray and feeds the sheet to the image forming unit. The sheets stored in the tray include not only so-called plain paper but also special sheets such as coated paper, which has a coated surface. In the past, sheets stacked on the tray would stick together, making it impossible to separate them during feeding, resulting in double-sheet feeding. This type of sheet sticking is more likely to occur in high humidity.

[0003] In order to prevent sheets from sticking together, it has been known to blow warm air onto the sheets stacked on the tray. For example, a sheet feeding device has been proposed that does not blow excessively hot air onto the sheets when replacing them (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2022-10479 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional sheet feeder described above, when the sheet storage compartment is removed from the device body, the air blower stops and the heating unit continues heating. Therefore, for example, if the entire sheet storage compartment is not fully removed, the sheets stored in the storage compartment are heated in a windless environment. In this case, if the sheet becomes hot in parts, and if the storage compartment is returned to the loading position as is, the temperature distribution of the sheet may become uneven, which may adversely affect the image quality when an image is formed on that sheet. Furthermore, even if additional sheets are added to the storage compartment, heat may be transferred to the added sheets, which may result in a deterioration in image quality when an image is formed on the added sheets. Furthermore, even when no sheets are stored in the storage compartment, if the storage compartment is heated in a windless environment, the storage compartment may become hot in parts. In this case, heat from the storage compartment may be transferred to sheets added to the storage compartment, which may adversely affect the image quality when an image is formed on the added sheets. Furthermore, if heating continues in a windless environment, the temperature inside the device body may rise rapidly, which may activate a protection circuit such as a thermo-cut in the heating compartment, causing an abnormal shutdown.

[0006] The object of the present invention is to provide a sheet feeding device and an image forming device that can prevent abnormal overheating of the heating section even when the sheet storage section is pulled out from the device main body during sheet feeding operation, and can suppress adhesion of sheets in the sheet storage section. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a sheet feeding device including a sheet storage unit attached to a main body of the device so as to be removable from the main body of the device, a blower unit that blows air toward sheets in the sheet storage unit, a heater unit that heats the air blown by the blower unit, and a controller that controls the blower unit and the heater unit. In the sheet feeding device, the controller drives the blower unit and the heater unit during a sheet feeding operation for feeding sheets from the sheet storage unit, and when the sheet storage unit is removed from the main body of the device during the sheet feeding operation, the controller continues to drive the blower unit and stops the heater unit.

[0008] An image forming apparatus according to another aspect of the present invention includes the sheet feeding device described above, and an image forming section that forms an image on the sheet fed by the sheet feeding device. [Effects of the Invention]

[0009] According to the present invention, even if the sheet storage unit is pulled out from the device main body during a sheet feeding operation, it is possible to prevent abnormal overheating of the heating unit and to suppress adhesion of sheets in the sheet storage unit. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing the configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the internal configuration of the image forming apparatus according to the embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view showing the configuration of a sheet storage unit included in the image forming apparatus according to the embodiment of the present invention. [Figure 4] FIG. 4 is a block diagram showing the configuration of the control unit of the image forming apparatus. [Figure 5] FIG. 5 is a flowchart showing a first example of the procedure of the sheet blowing process executed by the control unit of the image forming apparatus. [Figure 6] FIG. 6 is a flowchart showing a second example of the procedure of the sheet blowing process executed by the control unit of the image forming apparatus. [Figure 7] FIG. 7 is a flowchart showing a third example of the procedure of the sheet blowing process executed by the control unit of the image forming apparatus. DETAILED DESCRIPTION OF THE INVENTION

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

[0012] For ease of explanation, the vertical direction in the installation state where image forming apparatus 10 is usable (the state shown in FIG. 1) is defined as up-down direction 7. Furthermore, the front (front face) is the face into which paper feeder 24 (an example of a sheet storage device of the present invention) shown in FIG. 1 is inserted and removed in the installation state, and a front-rear direction 8 is defined. Furthermore, a left-right direction 9 is defined based on the front face of image forming apparatus 10 in the installation state.

[0013] The image forming apparatus 10 according to the embodiment of the present invention is an apparatus equipped with at least a printing function. The image forming apparatus 10 is a so-called tandem type color printer. However, the image forming apparatus 10 may also be a monochrome printer.

[0014] 1 and 2, the image forming apparatus 10 includes a housing 10A (an example of the apparatus main body of the present invention). The housing 10A has a generally rectangular parallelepiped shape. Inside the housing 10A, the various components that make up the image forming apparatus 10 are arranged.

[0015] As shown in Fig. 2, image forming apparatus 10 includes four image forming units 4, intermediate transfer belt 5, optical scanning device 13, secondary transfer roller 20, fixing device 16, sheet tray 18, paper feeder 24, operation display unit 25 (see Fig. 1), belt cleaning device 6, blower fan 35 (an example of a blower unit of the present invention), heater 36 (an example of a heating unit of the present invention), and control unit 90 (see Fig. 4). Note that image forming units 4, intermediate transfer belt 5, secondary transfer roller 20, and fixing device 16 are examples of image forming units of the present invention. Also, paper feeder 24, blower fan 35, and heater 36 are examples of sheet feeding devices of the present invention.

[0016] Each image forming unit 4 includes a photosensitive drum, a charging device, a developing device, a primary transfer roller, etc., and forms an image on the intermediate transfer belt 5 according to an electrophotographic system. The image forming units 4 are arranged side by side in the front-to-rear direction 8 inside the housing 10A, and form a color image according to a so-called tandem system. The image forming units 4 transfer toner images of each color onto the intermediate transfer belt 5 in a superimposed manner, thereby forming a color toner image on the intermediate transfer belt 5. The toner image on the intermediate transfer belt 5 is transferred by a secondary transfer roller 20 onto a printing paper (an example of a sheet of the present invention) fed from a paper feeder 24. Note that the image forming units 4 are not limited to those that perform image formation processing according to an electrophotographic system, and may be those that perform image formation processing according to an inkjet recording system, for example.

[0017] The intermediate transfer belt 5 is provided above the four image forming units 4. The intermediate transfer belt 5 is supported by a drive roller 5A and a driven roller 5B so that it can be rotated. By being supported by the drive roller 5A and the driven roller 5B, the intermediate transfer belt 5 can move in the direction of arrow 19 while its surface is in contact with the surface of each photosensitive drum.

[0018] The optical scanning device 13 is provided below the four image forming units 4. The optical scanning device 13 forms an electrostatic latent image on each photosensitive drum of the image forming units 4 by irradiating the photosensitive drum of each image forming unit 4 with laser light based on input image data for each color.

[0019] The paper feeder 24 is provided at the bottom of the housing 10A. The paper feeder 24 has a sheet storage section 41 and a feeding mechanism 32. A plurality of sheets of printing paper (corresponding to sheets of the present invention) are stored in the sheet storage section 41. A vertical conveying path 26 is formed on the rear side of the housing 10A, leading from the paper feeder 24 to the fixing device 16 via the secondary transfer roller 20. The feeding mechanism 32 takes out the printing paper stacked in the sheet storage section 41 one by one and feeds it toward the vertical conveying path 26.

[0020] The secondary transfer roller 20 is provided at a position facing the drive roller 5 A on the rear side of the housing 10 A. The secondary transfer roller 20 transfers the toner image from the intermediate transfer belt 5 onto the printing paper.

[0021] The fixing device 16 is provided above the secondary transfer roller 20. The fixing device 16 applies heat to the printing paper to fix the toner image to the printing paper. The fixing device 16 has a pair of rollers: a heating roller 16A and a pressure roller 16B. The heating roller 16A is located more inward than the pressure roller 16B in the housing 10A. The heating roller 16A is heated by a heating device. The printing paper transported from the secondary transfer roller 20 to the fixing device 16 is conveyed while being sandwiched between the heating roller 16A and the pressure roller 16B. At this time, heat is transferred from the heating roller 16A to the printing paper, and the toner on the printing paper melts and is fixed to the printing paper. This forms a color image on the printing paper.

[0022] A discharge path 28 is formed between the fixing device 16 and the sheet discharge outlet 27. The printing paper that has passed through the fixing device 16 is transported along the discharge path 28 by discharge rollers 23 and is discharged from the sheet discharge outlet 27 to the sheet tray 18.

[0023] Fig. 3 is a diagram showing a cross section of sheet storage section 41. Sheet storage section 41 stores multiple sheets of printing paper that are fed rearward during image formation. As shown in Fig. 3, sheet storage section 41 has an opening 411 on its top surface and is formed in the shape of a rectangular box or tray with a space 412 inside which printing paper can be stacked. Multiple sheets of printing paper are stored in sheet storage section 41.

[0024] A lift plate 45 that moves up and down in the vertical direction 7 is attached to the bottom 46 of the sheet storage section 41. The lift plate 45 is provided on the rear side of the bottom 46. Printing paper is loaded on the lift plate 45. The front end of the lift plate 45 is rotatably supported on the bottom 46 of the paper feeder 24, and the rear end of the lift plate 45 is a free end. The lift plate 45 is displaced in the vertical direction 7 by receiving a driving force from a motor (not shown). As a result, the lift plate 45 moves up and down in the vertical direction 7 together with the printing paper.

[0025] The sheet storage unit 41 is attached to the housing 10A so as to be removable from the housing 10A. The sheet storage unit 41 is supported so as to be insertable into and removable from the housing 10A. The housing 10A supports the sheet storage unit 41 so that it can be displaced between an attached position where it is attached to the housing 10A and a detached position where it is pulled out from the attached position.

[0026] The housing 10A is provided with a position detection sensor 37 (see FIG. 4) for detecting whether the sheet storage unit 41 is in the installation position. The position detection sensor 37 is connected to the control unit 90. When the sheet storage unit 41 is located in the installation position, the position detection sensor 37 sends a signal indicating that the sheet storage unit 41 is installed to the control unit 90, and the control unit 90 determines based on this signal that the sheet storage unit 41 is located in the installation position, i.e., that the sheet storage unit 41 is installed in the housing 10A. On the other hand, when the sheet storage unit 41 is not located in the installation position, the position detection sensor 37 sends a signal indicating that the sheet storage unit 41 is not installed to the control unit 90, and the control unit 90 determines based on this signal that the sheet storage unit 41 is not located in the installation position, i.e., that the sheet storage unit 41 has been pulled out of the housing 10A.

[0027] The blower fan 35 is a blowing device that blows air toward the sheets stacked in the sheet storage section 41. As shown in FIG. 3 , the blower fan 35 is provided above the sheet storage section 41 of the paper feeder 24. The blower fan 35 is provided at a rearward position above the sheet storage section 41. The blower fan 35 is attached to an internal frame such as the housing 10A so that its air outlet faces downward. The intake port of the blower fan 35 faces upward. Therefore, when the blower fan 35 is driven, it sucks in air from above and blows the air toward the top surfaces of the sheets stacked in the sheet storage section 41. The blower fan 35 is driven and controlled by the control unit 90.

[0028] The heater 36 is a heating device for heating the sheets stored in the sheet storage section 41. The heater 36 is provided above the blower fan 35. The heater 36 heats the air blown by the blower fan 35. The heater 36 radiates heat downward. The air heated by the heater 36 is sucked in by the blower fan 35 and blown toward the sheets stored in the sheet storage section 41. The heater 36 is, for example, a halogen heater or an IH heater. The heater 36 is driven and controlled by the control section 90.

[0029] The heater 36 is provided with a temperature sensor 361 such as a thermostat or thermo-cut for measuring temperature abnormalities of the heater 36. Specifically, the temperature sensor 361 is a thermo-cut that serves as a protection circuit for protecting the heater 36 from temperature abnormalities, and is connected in series to the power supply line of the heater 36. When the temperature sensor 361 detects an abnormal temperature, it cuts off the power supply line and stops the power supply to the heater 36.

[0030] In an image forming apparatus 10 equipped with a blower fan 35 and a heater 36, if the sheet storage unit 41 is pulled out from the housing 10A, stopping the blower fan 35 and continuing to heat the heater 36 can cause the following problems. For example, if the sheet storage unit 41 is not fully pulled out, the print paper stored in the sheet storage unit 41 is heated in a windless state. In this case, if the print paper becomes hot in parts, and if the sheet storage unit 41 is returned to the housing 10A as is, the temperature distribution of the print paper may become uneven, which may adversely affect the image quality when the print paper is fed and an image is formed on the print paper. Furthermore, if additional print paper is added to the sheet storage unit 41, heat may be transferred to the added print paper, which may also result in a degradation of image quality when an image is formed on the added print paper. Furthermore, even if no print paper is stored in the sheet storage unit 41, if the sheet storage unit 41 is heated in a windless state, the sheet storage unit 41 may become hot in parts. In this case, heat from sheet storage section 41 may be transferred to the print paper stored in sheet storage section 41, which may have a negative effect on the image quality when the print paper is fed and an image is formed on the print paper. Also, if heating by heater 36 continues in a windless environment, the temperature inside housing 10A may rise sharply, activating the protection circuit of temperature sensor 361 of heater 36 and cutting off the power supply line to heater 36, which may result in an abnormal shutdown.

[0031] In contrast, in this embodiment, the control unit 90 performs the sheet blowing process (see Figures 5 to 7) described below, so even if the sheet storage unit 41 is pulled out of the housing 10A during the printing paper feeding operation, it is possible to prevent abnormal overheating of the heater 36 and to prevent printing papers from sticking together in the sheet storage unit 41.

[0032] [Control unit 90] The control unit 90 controls the image forming apparatus 10 as a whole, and also controls the driving of the blower fan 35 and the heater 36 to perform a sheet blowing process, which will be described later.

[0033] 4, the control unit 90 is composed of a CPU 91, a RAM 92, a ROM 93, a storage unit 94, etc. The control unit 90 is electrically connected to the blower fan 35, the heater 36, the position detection sensor 37, etc. by signal lines, etc. The blower fan 35 and the heater 36 are driven and controlled by receiving individual control signals from the control unit 90.

[0034] The CPU 91 is a processor that executes computer programs to perform various data processing and predetermined control. The RAM 92 is a computer-readable volatile or nonvolatile storage device. The RAM 92 temporarily stores the computer programs executed by the CPU 91 and data output or referenced by the CPU 91 during the execution of various processes. The ROM 93 is a nonvolatile storage device that pre-stores control programs such as a BIOS and an OS that cause the CPU 91 to execute various arithmetic processes. The storage unit 94 is a flash memory that stores various information. The storage unit 94 stores control programs for executing various processes by the control unit 90, as well as data, thresholds, reference values, and the like used in the various processes. The storage unit 94 may also be a nonvolatile storage device such as an HDD or SSD connected to the control unit 90.

[0035] The control unit 90 controls the operation of the blower fan 35 and the heater 36 by the CPU 91 executing various control programs pre-stored in the ROM 93 or the memory unit 94, thereby performing the sheet blowing process (see Figures 5 to 7) described below.

[0036] 4, the control unit 90 includes various processing units such as a heating control unit 95 and an air volume control unit 96. Note that in this embodiment, not all of these processing units are necessarily required, and some may be omitted.

[0037] The control unit 90 functions as the various processing units by the CPU 91 executing various arithmetic processes in accordance with the control program. The control unit 90 or the CPU 91 is an example of a computer or processor that executes the control program. Note that some or all of the processing units included in the control unit 90 may be configured with electronic circuits. Furthermore, the control program may be a program that causes multiple processors to function as the various processing units.

[0038] The heating control unit 95 controls the driving or stopping of the heater 36. The heating control unit 95 also controls the output of the heater 36 by feedback control based on a comparison between a temperature detected by a temperature sensor (not shown) that detects the temperature around the sheet storage unit 41 and a predetermined target temperature.

[0039] In this embodiment, the heating control unit 95 drives the heater 36 and controls heating by the heater 36 during a sheet feeding operation in which print paper is fed from the sheet storage unit 41 in response to input of a print job in the image forming apparatus 10. Furthermore, the heating control unit 95 stops the heater 36 when it is determined that the sheet storage unit 41 has been pulled out from the housing 10A during the sheet feeding operation.

[0040] The air volume control unit 96 controls whether to drive or stop the blower fan 35. The air volume control unit 96 also controls the volume of air that the blower fan 35 blows.

[0041] In this embodiment, the air volume control unit 96 drives the blower fan 35 and controls the air flow by the blower fan 35 during a sheet feeding operation in which printing paper is fed from the sheet storage unit 41 in response to input of a print job in the image forming apparatus 10. Furthermore, when the air volume control unit 96 determines that the sheet storage unit 41 has been pulled out of the housing 10A during the sheet feeding operation, the air volume control unit 96 does not immediately stop the blower fan 35 but continues to drive the blower fan 35.

[0042] Specifically, when the sheet storage section 41 is pulled out from the housing 10A during the sheet feeding operation, the air volume control section 96 reduces the air volume blown by the blower fan 35 from a predetermined standard air volume to an air volume lower than the standard air volume.

[0043] Furthermore, the air volume control unit 96 counts the elapsed time after the heating control unit 95 stops the heater 36, and stops the blower fan 35 when it determines that a predetermined set time has elapsed.

[0044] Specifically, the air volume control unit 96 changes the set time according to the driving time during which the heater 36 is driven from the time when the heater 36 starts to be driven until the sheet storage section 41 is pulled out from the housing 10A during the sheet feeding operation.

[0045] For example, if the sheet storage unit 41 is pulled out during the sheet feeding operation, the heater 36 is heated to a higher temperature the longer the driving time up to that point. Therefore, in this case, the air volume control unit 96 sets the set time to a longer time the longer the driving time. Specifically, if the driving time is longer than a predetermined reference driving time, the air volume control unit 96 sets the set time to a calculated value obtained by adding an increase value proportional to the time difference between the driving time and the reference driving time to the reference driving time. This ensures that the residual heat of the heater 36 is reduced and the heater 36 is cooled reliably when the sheet storage unit 41 is pulled out.

[0046] Furthermore, if the sheet storage unit 41 is pulled out during the sheet feeding operation, the shorter the drive time up to that point, the less hot the heater 36 will be. Therefore, in this case, the shorter the drive time, the shorter the set time will be set by the air volume control unit 96. Specifically, if the drive time is shorter than the reference drive time, the air volume control unit 96 sets the set time to a calculated value obtained by subtracting a value proportional to the time difference between the drive time and the reference drive time from the reference drive time. This allows the residual heat of the heater 36 to be efficiently reduced and the heater 36 to be reliably cooled when the sheet storage unit 41 is pulled out.

[0047] In another embodiment, the air volume control unit 96 may set the set time to a first time that is longer than a predetermined initial setting time when the drive time is equal to or greater than a predetermined first threshold. In this case, the air volume control unit 96 maintains the set time at the initial setting time when the drive time is less than the first threshold and equal to or greater than a second threshold that is smaller than the first threshold. Furthermore, the air volume control unit 96 sets the set time to a second time that is shorter than the initial setting time when the drive time is less than the second threshold. Note that the first threshold and the second threshold can be set arbitrarily.

[0048] Furthermore, the air volume control unit 96 changes the air volume of the blower fan 35 after the heater 36 is stopped, depending on the driving time of the blower fan 35 and the heater 36 during the sheet feeding operation.

[0049] For example, if the sheet storage unit 41 is pulled out during the sheet feeding operation, the longer the driving time up to that point, the more the drying of the printing paper by the blower fan 35 and heater 36 is accelerated, and the printing paper is sufficiently dried. As a result, the adhesion between the printing sheets is low, and the wind force of the blower fan 35 may cause the printing paper to become misaligned. In this case, the air volume control unit 96 reduces the air volume of the blower fan 35 as the driving time is longer. This prevents the printing paper from becoming misaligned due to the wind force when the sheet storage unit 41 is pulled out.

[0050] Furthermore, if the sheet storage section 41 is pulled out during the sheet feeding operation, the shorter the drive time up to that point, the less the drying of the printing paper by the blower fan 35 and heater 36 has been promoted, and the drying is likely to be insufficient. Therefore, the adhesion between the printing sheets is not reduced, and even if the air force of the blower fan 35 is somewhat strong, it is likely that this will not affect the alignment of the printing paper. In this case, the air volume control section 96 increases the air volume of the blower fan 35 as the drive time becomes shorter. This allows the heater 36 to cool down faster when the sheet storage section 41 is pulled out, without disrupting the alignment of the printing paper due to wind force.

[0051] In another embodiment, the air volume control unit 96 may set the set air volume of the blower fan 35 to a first air volume that is weaker than a predetermined initial air volume when the drive time is equal to or greater than the predetermined first threshold. In this case, the air volume control unit 96 sets the set air volume to a second air volume that is stronger than the first air volume and weaker than the initial air volume when the drive time is less than the first threshold and equal to or greater than the second threshold. Furthermore, the air volume control unit 96 sets the set air volume to a third air volume that is stronger than the second air volume and weaker than the initial air volume, or the initial air volume when the drive time is less than the second threshold.

[0052] [First example of sheet air blowing treatment] An example of the procedure of the sheet air blowing process (first process example) executed by the control unit 90 will be described below with reference to Fig. 5. In the figure, S11, S12, ... indicate the numbers (step numbers) of the process procedures.

[0053] Note that one or more steps included in the sheet air blowing process described below may be omitted as appropriate. Furthermore, the order of execution of each step in the sheet air blowing process may be different as long as the same operational effect is achieved. Furthermore, the following description will be given using an example in which one processor corresponding to the control unit 90 executes each step in the sheet air blowing process, but the steps in the sheet air blowing process may be executed in a distributed manner by multiple processors.

[0054] The sheet blowing process described below is executed when a print job for printing an image on printing paper in the sheet storage section 41 is input to the image forming device 10 while the sheet storage section 41 is attached to the housing 10A.

[0055] As shown in Fig. 5, in step S11, the control unit 90 acquires type information of the printing paper used in the image forming process. The type information is information that indicates the type of printing paper. The type of printing paper can be identified by various factors, such as the basis weight of the printing paper, the thickness of the printing paper, whether the printing paper is coated, and the thickness of the coating layer. Specific examples include so-called plain paper, which is not coated, and so-called coated paper, which is coated.

[0056] For example, if paper information including type information of the printing paper stored in the sheet storage section 41 is stored in the memory section 94 of the control section 90, the control section 90 obtains type information of the printing paper to be image-formed from the memory section 94 and determines the type of printing paper in the sheet storage section 41.

[0057] In the next step S12, the control unit 90 determines, based on the acquired type information, whether or not it is necessary to blow hot air onto the print paper in the sheet storage unit 41. Specifically, if the print paper stored in the sheet storage unit 41 is coated paper, it determines that it is necessary to blow hot air onto the print paper, and if it is plain paper, it determines that it is not necessary. If it is determined that it is not necessary, the series of processes ends.

[0058] If it is determined in step S12 that blowing of hot air is necessary, the control unit 90 drives the heater 36 to start heating control by the heater 36 (S13). The control unit 90 also drives the blower fan 35 to start blowing air by the blower fan 35. As a result, hot air is blown onto the printing paper stored in the sheet storage unit 41 (S14).

[0059] In step S15, the control unit 90 determines whether the sheet storage unit 41 has been pulled out from the housing 10A. If the sheet storage unit 41 remains attached to the housing 10A, the process ends on the condition that all paper feeding corresponding to the print job has been completed (S16).

[0060] On the other hand, if it is determined in step S15 that the sheet storage section 41 has been pulled out from the housing 10A, the control section 90 stops the heater 36 (S17) and reduces the air volume of the blower fan 35. The degree of reduction in the air volume can be determined by multiplying the initial set air volume by a predetermined reduction rate (for example, 50%).

[0061] Thereafter, the control unit 90 determines whether the time that has elapsed since the heater 36 was stopped has exceeded the set time (S19), and stops the blower fan 35 if it is determined that the elapsed time has elapsed.

[0062] As described above, when the sheet storage section 41 is pulled out from the housing 10A during sheet feeding operation, the blower fan 35 continues to operate and the heater 36 is stopped, thereby preventing the heater 36 from overheating abnormally and preventing the printing papers in the sheet storage section 41 from sticking together.

[0063] In the first processing example described above, the air volume of the blower fan 35 is reduced after the heater 36 is stopped, but for example, the air volume of the blower fan 35 may not be reduced and the air may be blown at the same initial set air volume.

[0064] [Second example of sheet air blowing treatment] Hereinafter, an example (second processing example) of the procedure of the sheet air blowing process executed by the control unit 90 will be described with reference to Fig. 6. Note that the same step numbers are used to indicate the procedures with the same processing content as in the first processing example described above, and detailed description thereof will be omitted.

[0065] 6, when it is determined in step S15 that the sheet storage unit 41 has been pulled out, the control unit 90 acquires the driving time during which the heater 36 is driven from when the heater 36 starts to be driven until the sheet storage unit 41 is pulled out from the housing 10A during the sheet feeding operation (S151). The control unit 90 counts the time from when the heater 36 starts to be driven after the print job is input until the sheet storage unit 41 is pulled out as the driving time.

[0066] In the next step S152, the control unit 90 changes the set time in accordance with the drive time. That is, the control unit 90 sets the set time to a set value in accordance with the drive time. Thereafter, the processes from step S17 onward described above are executed.

[0067] Even in this second processing example, it is possible to prevent the heater 36 from overheating abnormally, and to prevent the print sheets in the sheet storage section 41 from sticking together.

[0068] [Third example of sheet air blowing treatment] Hereinafter, an example (third processing example) of the procedure of the sheet air blowing process executed by the control unit 90 will be described with reference to Fig. 7. Note that the same step numbers are used to indicate the procedures with the same processing content as the first and second processing examples described above, and detailed descriptions thereof will be omitted.

[0069] As shown in FIG. 7, when it is determined in step S15 that the sheet storage unit 41 has been pulled out, the control unit 90 acquires the driving time.

[0070] In the next step S152, the control unit 90 determines whether the drive time is equal to or greater than the first threshold value. If the drive time is equal to or greater than the first threshold value, the control unit 90 proceeds to step S153, and if the drive time is less than the first threshold value, the control unit 90 proceeds to step S155.

[0071] In step S153, the control unit 90 sets the set time used in step S19 to a first time that is longer than a predetermined initial setting time. In step S154, the control unit 90 sets the set air volume of the blower fan 35 to the first air volume that is weaker than the predetermined initial setting air volume. Thereafter, the processes from step S17 onwards are carried out.

[0072] In step S155, the control unit 90 determines whether the drive time is less than the first threshold and equal to or greater than the second threshold. If the drive time is less than the first threshold and equal to or greater than the second threshold, the control unit 90 proceeds to step S156, and if the drive time is less than the second threshold, the control unit 90 proceeds to step S158.

[0073] In step S156, the control unit 90 maintains the set time used in step S19 at the initial set time. In addition, in step S157, the control unit 90 sets the set air volume of the blower fan 35 to the second air volume, which is stronger than the first air volume and weaker than the initial set air volume. Thereafter, the processing from step S17 onwards described above is executed.

[0074] In step S158, the control unit 90 sets the set time to the second time, which is shorter than the initial setting time. The control unit 90 also sets the set airflow rate to a third airflow rate, which is stronger than the second airflow rate but weaker than the initial setting airflow rate, or to the initial setting airflow rate. Then, the process from step S17 onwards is carried out.

[0075] Even in the third processing example, it is possible to prevent the heater 36 from overheating abnormally, and to prevent the print sheets in the sheet storage section 41 from sticking together.

[0076] [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.

[0077] <Appendix 1> a sheet storage unit attached to the device body so as to be able to be pulled out from the device body; a blower that blows air toward the sheets in the sheet storage section; a heating unit that heats the air blown by the air blowing unit; a control unit that controls the air blower and the heating unit, The control unit driving the air blowing unit and the heating unit during a sheet feeding operation of feeding a sheet from the sheet storage unit; The sheet feeding device further includes a step of driving the air blowing unit and stopping the heating unit when the sheet storage unit is pulled out from the device body during the sheet feeding operation.

[0078] <Appendix 2> The control unit The sheet feeding device according to claim 1, wherein when the sheet storage unit is pulled out from the device body during the sheet feeding operation, the air volume blown by the air blowing unit is reduced from a reference air volume to an air volume lower than the reference air volume.

[0079] <Appendix 3> The control unit 3. The sheet feeding device according to claim 1, wherein the blowing unit is stopped when a predetermined set time has elapsed after the heating unit is stopped.

[0080] <Appendix 4> The control unit 4. The sheet feeding device according to claim 3, wherein the set time is changed depending on the driving time of the heating unit until the sheet storage unit is drawn out from the device body.

[0081] <Appendix 5> The control unit The sheet feeding device according to claim 4, wherein the set time is made longer as the driving time is longer, and the set time is made shorter as the driving time is shorter.

[0082] <Appendix 6> The control unit When the drive time is equal to or greater than a predetermined first threshold, the set time is set to a first time that is longer than an initial set time; When the driving time is less than the first threshold value and is equal to or greater than a second threshold value which is smaller than the first threshold value, the set time is maintained at the initial setting time; 6. The sheet feeding device according to claim 5, wherein, when the driving time is less than the second threshold value, the set time is set to a second time that is shorter than the initial setting time.

[0083] <Appendix 7> The control unit A sheet feeding device described in any one of appendixes 1 to 6, wherein the air volume of the blower unit after the heating unit is stopped is changed depending on the operating time of the heating unit until the sheet storage unit is pulled out from the device main body.

[0084] <Appendix 8> The control unit When the driving time is equal to or longer than a predetermined first threshold, the set airflow rate of the blower unit is set to a first airflow rate that is weaker than an initial set airflow rate; When the driving time is less than the first threshold and equal to or greater than a second threshold that is smaller than the first threshold, the set airflow rate is set to a second airflow rate that is stronger than the first airflow rate and weaker than the initial setting airflow rate; A sheet feeding device as described in Appendix 7, wherein when the driving time is less than the second threshold, the set air volume is set to a third air volume that is stronger than the second air volume and weaker than the initial setting air volume, or to the initial setting air volume.

[0085] <Appendix 9> a sheet feeding device according to any one of appendixes 1 to 8; an image forming unit that forms an image on the sheet fed by the sheet feeding device; An image forming apparatus comprising: [Explanation of symbols]

[0086] 10: Image forming device 10A: Housing 24: Paper feeder 32: Feeding mechanism 35: Blower fan 36: Heater 37: Position detection sensor 41: Sheet storage area 45: Lift board 46: Bottom 90: Control unit 95: Heating control unit 96: Air volume control unit 361: Temperature sensor

Claims

1. a sheet storage unit attached to the device body so as to be able to be pulled out from the device body; a blower that blows air toward the sheets in the sheet storage section; a heating unit that heats the air blown by the air blowing unit; a control unit that controls the air blower and the heating unit, The control unit driving the air blowing unit and the heating unit during a sheet feeding operation of feeding a sheet from the sheet storage unit; The sheet feeding device further includes a step of driving the air blowing unit and stopping the heating unit when the sheet storage unit is pulled out from the device body during the sheet feeding operation.

2. The control unit The sheet feeding device according to claim 1 , wherein, when the sheet storage unit is pulled out from the device body during the sheet feeding operation, the air volume blown by the blower unit is reduced from a reference air volume to an air volume lower than the reference air volume.

3. The control unit 3. The sheet feeding device according to claim 1, wherein the air blowing unit is stopped when a predetermined set time has elapsed after the heating unit is stopped.

4. The control unit The sheet feeding device according to claim 3 , wherein the set time is changed depending on the driving time of the heating unit until the sheet storage unit is drawn out from the device main body.

5. The control unit The sheet feeding device according to claim 4 , wherein the set time is made longer as the driving time is longer, and the set time is made shorter as the driving time is shorter.

6. The control unit When the drive time is equal to or greater than a predetermined first threshold, the set time is set to a first time that is longer than an initial set time; When the driving time is less than the first threshold value and is equal to or greater than a second threshold value which is smaller than the first threshold value, the set time is maintained at the initial setting time; The sheet feeding device according to claim 5 , wherein, when the driving time is less than the second threshold value, the set time is set to a second time that is shorter than the initial setting time.

7. The control unit The sheet feeding device according to claim 1 , wherein the air volume of the blower unit after the heating unit is stopped is changed according to the operating time of the heating unit until the sheet storage unit is drawn out from the device body.

8. The control unit When the driving time is equal to or longer than a predetermined first threshold, the set air volume of the blower unit is set to a first air volume that is weaker than an initial set air volume; When the driving time is less than the first threshold and equal to or greater than a second threshold that is smaller than the first threshold, the set air volume is set to a second air volume that is stronger than the first air volume and weaker than the initial set air volume; The sheet feeding device according to claim 7 , wherein when the driving time is less than the second threshold, the set air volume is set to a third air volume that is stronger than the second air volume and weaker than the initial setting air volume, or to the initial setting air volume.

9. The sheet feeding device according to claim 1 or 2; an image forming unit that forms an image on the sheet fed by the sheet feeding device; An image forming apparatus comprising:

Images