Sheet Feeder

Abstract

To provide a sheet feeder which does not blow hot air having an excessive temperature onto a sheet during exchange of sheets.SOLUTION: A sheet feeder includes: a blower fan 42 which blows air onto a sheet on a loading tray 22; and a heater 43 which heats the air blown by the blower fan 42. When supply of the last sheet on a sheet feeding job is completed, the blower fan is operated to cool the heater 43 in a state that heating of the air by the heater 43 is stopped.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a paper feeder including a blower that blows air to sheets. [Background technology]

[0002] 2. Description of the Related Art Conventionally, image forming apparatuses such as printers and copiers are provided with a sheet feeding device that separates sheets stacked on a storage tray one by one and supplies the sheets to the image forming apparatus.

[0003] The sheet feeding device is provided with a liftable stacking tray on which sheets are stacked, a feeding means for contacting the upper surface of the sheet to feed it out, a separating means for separating the fed sheet into one sheet and feeding it, and a conveying means for conveying the separated sheet toward the image forming device. The sheet on the liftable tray is guided along the sheet feeding path to the image forming device by the feeding means, the separating means, and the conveying means.

[0004] Among such paper feeding devices, there is known one that is equipped with a heater consisting of a heater and a radiator that warms air, and a blower fan that blows air onto the sheets, and in which the blower fan blows warm air onto the edges of the sheets on the stacking tray to dehumidify the sheets while separating them (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-189181 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in a sheet feeder that blows air onto sheets to separate them, it is necessary to blow air at an optimal temperature depending on the type of sheet, such as the thickness, size, and material of the sheet. In other words, the temperature of the air blown onto the sheets is changed along with a change in the type of sheet on the stack tray. In this case, if printing is performed on a sheet onto which air heated to a temperature higher than the optimal temperature is blown, there is a risk of print unevenness occurring. Therefore, when changing the air temperature from a high temperature to a low temperature, it is necessary to wait until the heater temperature drops to a low temperature with the heater stopped. However, it takes a long time for the heater temperature to drop after it is stopped, and there is a problem that sheets cannot be fed during that time, resulting in reduced productivity.

[0007] An object of the present invention is to provide a sheet feeding device capable of reducing the temperature of air blown during sheet separation to a predetermined temperature in a short time and shortening the waiting time when performing a sheet feeding operation. [Means for solving the problem]

[0008] In order to solve the above problems, the sheet feeding device of the present invention comprises a loading tray for loading sheets, a feeding means for feeding the sheets on the loading tray, a blowing means for blowing air onto the sheets on the loading tray, a heating means for heating the air blown by the blowing means, and a sheet detection means arranged downstream of the feeding means for detecting sheets, and operates the blowing means while stopping the heating of the air by the heating means based on the sheet detection means detecting the final sheet in a paper feeding job in which a predetermined number of sheets are fed in succession. Effect of the Invention

[0009] According to the present invention, the temperature of the air blown during sheet separation can be reduced to a predetermined temperature in a short time, and the waiting time when performing a sheet feeding operation can be shortened. [Brief description of the drawings]

[0010] [Figure 1]1 is a cross-sectional view showing a configuration of an image forming system including a sheet feeding device according to the present invention. [Diagram 2] 1 is a conceptual diagram showing a configuration of a sheet feeding device according to the present invention; [Diagram 3] 5 is a diagram showing a state in which a storage case is pulled out in the sheet feeding device according to the present invention; FIG. [Figure 4] FIG. 2 is a block diagram showing the configuration of a control system of the sheet feeding device according to the present invention. [Diagram 5] FIG. 4 is an operational flowchart showing a sheet feeding operation of the sheet feeding device according to the present invention. [Figure 6] FIG. 4 is a flowchart showing a first air handling process in the sheet feeding operation of the sheet feeding device according to the present invention. [Figure 7] FIG. 6 is a flow chart showing a cooling process in a sheet feeding operation of the sheet feeding device according to the present invention. [Figure 8] FIG. 6 is an operation flowchart showing a drawer operation of a storage case of the sheet feeding device according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the attached drawings. FIG. 1 is a conceptual diagram showing an example of an image forming system including a paper feeder. The image forming system 1 is composed of an image forming apparatus 2 equipped with a document reading apparatus 3 and a document feeding apparatus 4, and a device connected to the image forming apparatus 2. The image forming apparatus 2 forms an image on a sheet supplied from one of an upper cassette 10, a lower cassette 11, or a paper feeder 5, in an image forming section 7 based on image data read from a document image by the document reading apparatus 3, and accumulates the image-formed sheet in an accumulation section 8. The document reading apparatus 3 can also be fed with a document sheet by the document feeding apparatus 4.

[0012] The image forming section 7 includes a charger 7a, a light projector (such as a laser head) 7b, a photosensitive drum 7c, a developing unit 7d, a transfer charger 7e, and a fixing roller 7f. An electrostatic latent image (still image) is formed by the light projector 7b on the surface of the photosensitive drum 7c charged by the charger 7a, and toner is attached to the electrostatic latent image by the developing unit 7d. The toner attached to the photosensitive drum 7c is then transferred by the transfer charger 7e to a sheet supplied from either the upper or lower cassettes 10, 11 or the paper feeder 5. The sheet to which the toner has been transferred is sent to the fixing roller 7f arranged downstream, where the toner on the sheet is heated and fixed, and then discharged to the stacking section 6 by a pair of paper discharge rollers 9.

[0013] The upper and lower cassettes 10 and 11 are each provided with a sheet feeding mechanism that feeds the sheets stored in each cassette 10 and 11. The sheet feeding mechanism includes a feed roller that contacts the uppermost surface of the sheet to feed the sheet, and a pair of separation rollers that separates the fed sheets one by one and feeds them. The sheets fed by the sheet feeding mechanism are transported through a transport path 12. Then, they are sent to the image forming unit 7 along a transport path 13.

[0014] The sheets handled by the image forming device 2 and the paper feeding device 5 include, in addition to plain paper, overhead projector sheets, tracing paper, coated paper, and the like, and also support a variety of sheet sizes.

[0015] The document reading device 3 transfers light onto a document transported to a predetermined reading position by the document feeding device 4, and receives the reflected light from the document with the photoelectric conversion element 3a. The photoelectric conversion element 3a then converts the received light into an electrical signal to generate image data from the document. The image data thus generated is transmitted to the light projector 7b of the image forming device 2 as an image signal.

[0016] FIG. 2 is a conceptual diagram showing the configuration of the sheet feeding device 5. As shown in FIG. 1, slide rails 21a and 21b are provided on both the left and right sides of a storage case 20 serving as a storage section. The storage case 20 is supported by a housing 50 of the device main body 5 so as to be able to be pulled out via the slide rails 21a and 21b. A sheet feeding mechanism 30 serving as a sheet feeding means includes a feed roller 31, a feed roller 32, and a separation roller 33, which are driven by a sheet feeding motor MT1. The sheets stored in the storage case 20 are fed by the feed roller 31, and are separated one by one by the feed roller 32 and the separation roller 33 and fed. In addition, a pair of conveying rollers 34a and 34b are provided downstream of the sheet feeding direction of the sheet feeding mechanism 30, and the sheets fed by the pair of conveying rollers 34a and 34b are supplied to the image forming device 2.

[0017] FIG. 3 is a diagram showing the storage 20 in a pulled-out state. FIG. 3(a) is a side view showing the storage 20 mounted in the paper feeder 5, and FIG. 3(b) is a side view showing the storage 20 pulled out from the paper feeder 5. FIG. 3(c) is a perspective view showing the storage 20 pulled out. The storage 20 is configured to be movable between a mounted position detected by the mounting detection sensor S5 as shown in FIG. 3(a) and a pulled-out position along the slide rails 21a and 21b as shown in FIG. 3(b) and FIG. 3(c). The storage 20 is held in the mounted position when feeding sheets. The storage 20 is pulled out when replacing the sheets on the stacking tray 22 with other types of sheets or when refilling the same sheets as those on the stacking tray 22.

[0018] A pull-out button 5a is provided on the top surface of the exterior of the paper feeder 5 to release the holding of the storage case 20 and allow it to be pulled out. A user presses the pull-out button 5a to release the holding of the storage case 20 and pull out the storage case 20, and after replacing or replenishing sheets, attaches the storage case 20 to the paper feeder 5 again. Although not shown, this embodiment is provided with a holding mechanism that holds the storage case 20 in the mounting position and releases the holding, and this holding mechanism is operated by an actuator such as a solenoid to allow the storage case 20 to be pulled out.

[0019] A stacking tray 22 that can be raised and lowered is provided inside the storage case 20. The stacking tray 22 is formed of a flat plate on which a plurality of sheets can be stacked. An upper surface detection sensor S1 that detects the position of the top surface of the sheets stacked on the stacking tray 22 is provided above the storage case 20, and a lower limit detection sensor S2 is provided below the storage case 20. The stacking tray 22 is configured to be raised and lowered by a lifting mechanism 28 between a position where it is raised a predetermined amount after being detected by the upper surface detection sensor S1 and a position where it is detected by the lower limit detection sensor S2.

[0020] The lifting mechanism 28 includes a wire 26 attached to the loading tray 22, a take-up pulley 27 that winds up the wire 26, and a lifting motor MT2 that rotates the take-up pulley 27 in one direction to wind up the wire 26 to lift the loading tray 22, and rotates the take-up pulley 27 in the other direction to slacken the wire 26 to lower the loading tray 22.

[0021] A pair of side regulating plates 23 are provided in the storage 20 to align the sheet width direction perpendicular to the sheet feed direction. The pair of side regulating plates 23, 24 are configured to be movable in the sheet width direction in accordance with the size of the sheets in the storage 20. Also, a rear end regulating plate 25 is provided that moves in the sheet feed direction to align the rear end of the sheet in the feed direction. Note that only the first side regulating plate 23 arranged on one end side in the sheet width direction is shown in Figs. 1 and 2.

[0022] A first air blowing mechanism 40 arranged downstream in the sheet feed direction and a second air blowing mechanism 50 arranged upstream in the sheet transport direction are provided on the rear side of the sheet regulating surface of the first side regulating plate 23. The first and second air blowing mechanisms 40, 50 blow air from their respective air outlets 41b, 51b to the sides of the sheets stacked on the stacking tray 22, lifting the sheets and allowing the air to penetrate between the sheets, thereby separating the sheets.

[0023] The first side regulating plate 23, the first air blowing mechanism 40, and the second air blowing mechanism 50 are integrated into a unit, and are configured so that the first air blowing mechanism 40 and the second air blowing mechanism 50 also move in conjunction with the movement of the first side regulating plate 23.

[0024] The first blowing mechanism 40 includes a first duct (air passage) 41 having an intake port 41a and an exhaust port 41b, a first blowing fan 42 as an air blowing means arranged in the duct 41, and a heater 43 as a heating means. The exhaust port 41b of the duct 41 is connected to a first exhaust opening 23a provided in the first side regulating plate 23, and is provided at a position where air is blown onto the upper part of the sheets loaded on the stacking tray 22. The first blowing fan 42 arranged in the first duct 41 is operated to blow air sucked from the intake port 41a of the first duct 41 from the exhaust port 41b onto the side of the sheets loaded on the stacking tray 22. When blowing hot air, the heater 43 is operated, and the air in the first duct 41 heated by the heater 43 is blown by the blowing fan 42 from the exhaust port 41b onto the side of the sheets.

[0025] Furthermore, a first louver 44 is provided on the side of the air outlet 41b in the first duct 41 of the first blowing mechanism 40 to change the range and direction of the air blown out from the air outlet 41b. The first louver 44 is controlled to swing up and down at a constant cycle when blowing air to separate sheets. This creates variations in the wind pressure of the air blown to the edge of the sheet, and the direction of the air changes, improving the accuracy of separating sheets.

[0026] The second blowing mechanism 50 is disposed upstream of the first blowing mechanism 40, and includes a second duct 51 having an intake port 51a and an exhaust port 51b, and a second blowing fan 52 disposed in the second duct 51. The exhaust port 51b of the second duct 51 is connected to a second exhaust opening 23b provided in the first side regulating plate 23, and is positioned to blow air onto the upper upstream side of the sheets stacked on the stacking tray 22. The second blowing fan 52 also blows air sucked from the intake port 51a of the first duct 51 onto the side of the sheets stacked on the stacking tray 22 from the exhaust port 51b.

[0027] The second blowing mechanism 50 is also provided with a second louver 45. This second louver 45 is controlled to swing up and down at a constant cycle in synchronization with the first louver 44 of the first blowing mechanism 40 when blowing air to separate the sheets. In other words, like the first louver 44 of the first blowing mechanism 40, the second louver 45 also varies the wind pressure of the air blown against the edge of the sheet, thereby changing the direction of the air.

[0028] The heater 43 of the first blowing mechanism 40 is composed of a heating element 43a made of a nichrome wire or the like and a heat sink 43b made of a plurality of fins. A thermistor S3 for detecting the temperature (heater temperature) of the heater 43 is attached to the heat sink 43b. When the heating element 43a is energized, it generates heat and turns the heater 43 on, and when the energization is cut off (stopped), it turns the heater 43 off. The heat sink 43b dissipates the heat transferred from the heating element 43a to heat the surrounding air over a wide range. As described above, the heated air is turned into hot air by the first blowing fan 42, flows through the first duct 41, and is blown from the air outlet 41 to the side of the seat. The thermistor S3 measures the surface temperature of the heat sink 43b. That is, in this embodiment, the surface temperature of the heat sink 43b is taken as the temperature of the heater (heating means).

[0029] Fig. 4 is a control system block diagram of the sheet feeding device 5 shown in Fig. 2. The sheet feeding device 5 is provided with a control unit 100 having a CPU, a ROM, a RAM, and a timer TM for measuring time. The sheet feeding device 5 also includes an upper surface detection sensor S1 for detecting the position of a sheet accompanying the elevation and lowering of the stacking tray 22, a lower limit detection sensor S2 for detecting the stacking tray 22 at the lower limit position, a thermistor S3 for measuring the temperature of the heater 43, an environmental temperature sensor S4 for detecting the temperature inside the storage case 20, an installation detection sensor S5 for detecting the installation state of the storage case 20, and a sheet detection sensor S6 disposed downstream of the sheet feeding mechanism 30 and for detecting a sheet being fed. Furthermore, the device is equipped with a paper feed motor MT1 which drives the feed roller 31, the paper feed roller 32 and the separation roller 33, a transport motor MT2 which drives one of the transport rollers 34a, a lift motor MT3 which raises and lowers the stacking tray 22, a heating element 43a of a heater 43 which warms the air to be blown, first and second fan motors MT4 and MT5 which drive two blower fans 42 and 52 which blow air to blow onto the sheets, and a rotation motor MT6 which rotates the first and second louvers 44 and 45.

[0030] The control unit 100 controls the driving of the paper feed motor MT1, the transport motor MT2, the lift motor MT3, the heater 43, and the first and second blower fans 42 and 52 based on various information from an operation unit 101 to which information on the size and material of the sheets, the type of the sheets such as special paper, and the printing mode such as double-sided printing, single-sided printing, reduced printing, and enlarged printing is input, as well as the results of detection and measurement by the upper surface detection sensor S1, the lower limit detection sensor S2, thermistor S3, the environmental temperature sensor S4, the installation detection sensor S5, and the sheet detection sensor S6. The control unit 100 also transmits information on errors due to damage to parts, lifting and lowering failure of the stacking tray 22, paper feed failure, etc. to the display unit 102, and notifies the same on the display unit 102.

[0031] Furthermore, operation unit 101 has a panel-shaped paper feed button for instructing the start of a paper feed operation, and pressing this paper feed button transmits a paper feed instruction signal, and upon receiving this signal, control unit 100 starts the paper feed operation. Note that, although control unit 100 is provided in paper feed device 5 in this embodiment, it may also be provided in image forming device 2 or image reading device 3. Furthermore, operation unit 101 and display unit 102 may also be attached to image forming device 2 or image reading device 3.

[0032] Here, the temperature control of the heater 43 will be explained. The control unit 100 controls the heater temperature to be kept constant near the set temperature by comparing the heater temperature measured by thermistor S3 with the set temperature set according to the sheet type.

[0033] Specifically, an upper limit value is set by adding a fixed value to the set temperature, and a lower limit value is set by subtracting a fixed value from the set temperature. When the temperature of thermistor S3 reaches the lower limit value with heater 43 stopped (OFF), heater 43 is operated (ON). When the upper limit value is reached with heater 43 turned ON, heater 43 is turned OFF. For example, if the set temperature is 60°C, the upper limit value is set to 61°C and the lower limit value is set to 59°C. As a result, heater 43 is turned ON when the temperature of thermistor S3 reaches 59°C, and heater 43 is turned OFF when it reaches 61°C with heater 43 ON. As a result, the temperature of heater 43 when the set temperature is 60°C is controlled to be between 59°C and 61°C.

[0034] In the air handling operation, when the storage 20 is attached to the device body from the drawn state and when the paper feed operation is started, the first and second blower fans 42, 52 are operated for a certain time to blow air onto the edge of the sheet. The air handling operation is also performed during the sheet feed operation. When the heater 43 is operated, if the temperature of the heater 43 reaches the set temperature, the first and second blower fans 42, 52 are operated to start the air handling.

[0035] Fig. 5 is an operational flow chart showing the paper feed operation. Fig. 6 is a flow chart showing the first air handling process in the paper feed operation, and Fig. 7 is a flow chart showing the cooling process of heater 43 in the paper feed operation. In the paper feed operation, when a paper feed instruction signal is received, the first air handling process is executed (ST01 to ST02). The paper feed instruction signal is generated when the user operates the paper feed button on operation unit 101.

[0036] 5, the first air handling process first acquires sheet information such as the paper quality, paper thickness (basis weight), size, etc. (ST02-1). The user inputs the sheet information by operating the operation unit 101, and whenever the type of sheet is changed, the user inputs new information by operating the operation unit 101.

[0037] Based on the input sheet information, it is determined whether or not air separation is necessary (ST02-2). If it is determined that air separation is not necessary, the air separation operation is terminated. On the other hand, if air separation is necessary, it is determined whether or not the heater 43 is necessary, that is, whether or not air separation using hot air is to be performed (ST02-3).

[0038] If it is determined that the heater 43 is necessary, the temperature of the heater 43 is measured by thermistor S3, and a set temperature adjustment process is executed (ST02-4 to ST02-5). In this set temperature adjustment process, the heater 43 is operated, and the temperature of the heater 43 measured by thermistor S3 is adjusted to a set temperature that is set according to the type of sheet.

[0039] When the temperature of the heater 43 reaches the set temperature and the temperature adjustment is completed, the first and second blower fans 42, 52 are operated (ON) to start air handling (ST02-6 to ST02-7). Then, the first and second blower fans 42, 52 are operated for a predetermined time to blow air toward the sides of the sheet through the first and second ducts 41, 51 to handle the air (ST02-8). On the other hand, if the heater 43 is not required, that is, if room temperature air is to be blown toward the sheet, the first and second blower fans 42, 52 are operated (ON) for a predetermined time with the heater 43 stopped without executing the set temperature adjustment process (ST02-3, ST02-7, ST02-8).

[0040] When the first air handling process is completed, a paper feed job is executed from step 03 (ST03) to step 05 (ST05). In the paper feed job, the paper feed process is executed first (ST03). The paper feed process operates the feed roller 31, the paper feed roller 32, the separation roller 33, and the conveying roller pair 34. As a result, the feed roller feeds the top sheet on the stack tray 22, and the sheet fed by the paper feed roller 32 and the separation roller 33 is separated into one sheet and fed. Then, the sheet is supplied to the image forming device 5 by the conveying roller pair 34. Then, when the rear end of the sheet supplied by the conveying roller pair 34 is detected by the sheet detection sensor S6, it is determined whether the detected sheet is the last sheet in the paper feed job (ST04 to ST05). Then, if it is not the last sheet, the paper feed process of the next sheet is executed.

[0041] On the other hand, if it is the last sheet, the temperature of the heater 43 measured by thermistor S3 at that time is compared with a predetermined temperature (ST06). If the comparison result indicates that the temperature of the heater 43 is equal to or higher than the predetermined temperature, the cooling process is executed, and if the temperature of the heater 43 is lower than the predetermined temperature, the cooling process is not executed (ST06 to ST07). In this embodiment, the above-mentioned predetermined temperature is a temperature obtained by adding a small value to the temperature measured by the environmental temperature sensor S4. This allows the cooling process to be executed only when the temperature of the heater 43 is high, and not executed when the temperature is low, such as when the heater 43 is not operating.

[0042] The cooling process is executed after the final sheet in the paper feed job is supplied, i.e., after the paper feed job is completed. In the cooling process, the first blower fan 42 is operated with the heater 43 stopped to make air flow along the first duct 41 until the temperature of the heater 43 becomes equal to or lower than a predetermined temperature. As a result, the heated air in the first duct 41 is blown out from the blow-out port 41b, and the air outside the first duct 41 is taken in from the suction port 41a. The air taken in from the suction port 41a flows in the duct 41 toward the blow-out port 41b while coming into contact with the heat radiator 43b of the heater 43, and cools the heater 43.

[0043] 7, first, the heater 43 is stopped (OFF) (ST07-1), and then the rotation speed of the first fan motor MT4 is maximized to maximize the wind speed of the first blower fan 42 (ST07-2). As a result, the heated air in the first duct 41 is blown out from the outlet 41b, and the air outside the first duct 41 is taken in from the intake 41a. The air taken in from the intake 41a flows in the first duct 41 toward the outlet 41b while coming into contact with the heat radiator 43b of the heater 43, and cools the heater 43.

[0044] Then, when the temperature of the heater 43 measured by thermistor S3 reaches a predetermined temperature, the first blower fan 42 is stopped (OFF) and the cooling process is terminated (ST07-3, ST07-5). If a paper feed instruction for the next paper feed job is acquired before the temperature of the heater 43 reaches the predetermined temperature, the first blower fan 42 is stopped (OFF) to forcibly terminate the cooling process and perform the paper feed operation (ST07-4, ST07-5). In this way, by cooling the heater 43 after the paper feed job is completed, air can be immediately removed even if the sheets on the stacking tray 22 are replaced with sheets of a different type.

[0045] Fig. 7 is an operational flow chart showing the operation of pulling out the storage case 20 from the paper feeder 5. The operation of pulling out the storage case 20 will be explained based on Fig. 7. When the user presses the pull-out button 5a shown in Fig. 3(c) to enable the storage case to be pulled out, the pull-out button 5a turns ON. When the pull-out button 5a turns ON, it is confirmed whether or not a paper feed job is in progress (ST10 to ST11).

[0046] If a paper feed job is in progress, the blower fans 42, 52 are stopped (turned OFF) (ST11 to ST12). At this time, if the heater 43 is operating, its operation continues. In other words, it is determined that the operation of pulling out the storage case 20 during a paper feed job is for replenishing sheets and that the type of sheets has not been changed, so the operation of the heater 43 continues. Of course, if the heater 43 is not operating, that state continues. As a result, the heater 43 is at the set temperature when the storage case 20 is installed, and the paper feed operation can be resumed immediately.

[0047] After the first and second blower fans 42 and 52 are stopped, the storage 20 is released from the mounted state (ST13). This allows the storage 20 to be pulled out. Then, the second air handling process is executed (ST15) after the mounting sensor S5 is turned from the OFF state to the ON state. In the second air handling process, the first and second blower fans 42 and 52 are operated (ON) for a predetermined time (ST15-1 to ST15-2). This causes air to be blown onto the edge of the sheet, and the sheet is handled. While the above-mentioned mounting sensor S5 is turned from the OFF state to the ON state, the storage 20 is pulled out by the user as shown in FIG. 3(b), and the sheet is replaced or replenished in this pulled out state. After that, the storage 20 is mounted as shown in FIG. 3(a).

[0048] If it is confirmed in step 11 (ST11) that a paper feed job is not in progress, it is confirmed whether the first air handling process is in progress (ST16). Furthermore, if it is confirmed that the first air handling process is not in progress, it is confirmed whether the cooling process is in progress (ST17). If it is confirmed in step 16 (ST16) that the first air handling process is in progress or if it is confirmed in step 17 (ST17) that the cooling process is in progress, the pull-out operation is terminated, and the pull-out operation is executed again after the first air handling process or the cooling process is completed.

[0049] If it is confirmed in step 17 (ST17) that the cooling process is not in progress, that is, if the paper feed job, the first air handling process, and the cooling process are all not being executed, the mounted state of the storage cabinet 20 is released (ST13). At this time, the heater 43 is cooled in the cooling process (ST07) and is in a stopped state, and the first blower fan 42 has finished the cooling process (ST07) and is in a stopped state, so the storage cabinet 40 can be pulled out without hindrance.

[0050] Thereafter, when the mounting sensor S5 is turned on, the blower fans 42, 52 are operated (ON) for a predetermined time to perform a second air handling process (ST14) for handling the sheets on the stacking tray 22 (ST14-1 to ST14-3). In this handling operation when the storage 20 is mounted, unlike the air handling operation before the paper feed operation is started, air is blown without adjusting the air temperature. This makes it possible to shorten the time required for adjusting the air temperature. At this time, if a paper feed job is in progress, it is determined that the storage is being pulled out for refilling, and air handling is performed at the set temperature before the storage is pulled out. On the other hand, if the operation is performed outside of a paper feed job, the heater 43 is sufficiently cooled by the cooling process, so that printing unevenness and the like do not occur on the sheets.

[0051] In the above embodiment, air is separated by the second air separation process when the storage 20 is attached, but air may be separated by the first air separation process also when the storage 20 is attached.

[0052] According to the above embodiment, instead of waiting for the heater 43 to cool naturally, the heater 43 is cooled by driving the blower fan 42 while the heater 43 is turned off, so that the temperature of the heater 43 in the duct 41 can be reduced in a short time.

[0053] In addition, since air handling was performed after the temperature of the heater 43 had cooled down, it took some time for air handling to start after the storage case 20 was installed depending on the type of sheet. However, in this embodiment, the cooling process is executed when the paper feed job is completed, so the time from installing the storage case 20 to starting air handling is shortened. [Explanation of symbols]

[0054] 2. Image forming device 5. Paper feeder 20 Storage 22 Loading Tray 30 Paper feed mechanism 31 Payout roller 32 Paper feed roller 33 Separation roller 34a, 34b Conveyor roller pair 23 First side regulating plate 40 First blower mechanism 50 Second blower mechanism 41 Duct 41a Suction port 41b Outlet 43 Heater 43a Heating element 43b Heat sink 42 First blower fan 100 Control unit 101 Operation unit S3 Thermistor S4 Ambient temperature sensor S5 Mounting detection sensor

Claims

1. A sheet feeding device including a stacking tray for stacking sheets, a sheet feeding means for feeding the sheets on the stacking tray, a blowing means for blowing air onto the sheets on the stacking tray, a heating means for heating the air blown by the blowing means, and a sheet detection means disposed downstream of the sheet feeding means for detecting the sheets, A sheet feeding device characterized in that when the final sheet in a paper feeding job in which a predetermined number of sheets are fed continuously is detected by the sheet detection means, if the heating means is heating the air, the heating of the air by the heating means is stopped and the air blowing means is operated.

2. 2. The sheet feeding apparatus according to claim 1, further comprising a temperature detector for detecting a temperature of said heating means, said air blower operating at least until said temperature detector detects a temperature equal to or lower than a predetermined temperature.

3. a storage section provided with the loading tray and attached to a device body so as to be removable; and an attachment detection means for detecting that the storage section is attached to the device body from a pulled-out state, 2. The sheet feeding device according to claim 1, wherein, based on detection by the mounting detection means of the storage section that the storage section is mounted, the heating means stops heating the air and the blowing means blows air onto the sheets on the stacking tray.

4. a sheet feeding device including a loading tray for loading sheets, a storage section in which the loading tray is provided and which is attached to a device body so as to be removable, an operation means for enabling the storage section to be removable, a sheet feeding means for feeding sheets on the loading tray, an air blowing means for blowing air onto the sheets on the loading tray, a heating means for heating the air blown by the air blowing means, and a sheet detection means disposed downstream of the sheet feeding means for detecting sheets, operating the air blowing means while stopping the heating of the air by the heating means, based on the detection by the sheet detection means of the final sheet in a paper feed job in which a predetermined number of sheets are fed consecutively; 11. A sheet feeding device comprising: a heating means for heating air; a heater for heating the air; a heater for heating the air; a heater for heating the air;

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