Sheet Feeder

Abstract

To cool a heater for heating air in a short time.SOLUTION: A cooling operation, in which a blower fan 42 is operated to cool a heater 43, is performed with the heater 43 stopped. Then, air is blown to a position which avoids an end part of a sheet when the cooling operation is performed.SELECTED DRAWING: Figure 6

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] Such paper feeding devices are known to be equipped with a heater consisting of a heater and a radiator that heats air, and a blower fan that blows air onto the sheets, and the air heated by the heater is blown as hot air by the blower fan 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 paper feeder that blows hot air onto sheets to separate them, it is necessary to blow hot 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 hot air blown onto the sheets is changed when the type of sheet on the stacking tray is changed. In this case, when changing the hot air temperature from high to low, it takes a long time for the temperature to drop to a low temperature after the heater is stopped. During that time, there is a problem that paper cannot be fed, which reduces productivity.

[0007] An object of the present invention is to provide a sheet feeding device capable of reducing the temperature of hot 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 a sheet feeding device equipped with a loading tray for loading sheets, a paper feeding means for feeding the sheets on the loading tray, a blowing means for blowing air to the ends of the sheets on the loading tray, and a heater for heating the air blown by the blowing means, the device is provided with a cooling means for cooling the heater by operating the blowing means while the heater is stopped, and a deflection means for blowing air in a direction that avoids the ends of the sheets when cooling the heater with the cooling means. Effect of the Invention

[0009] According to the paper feeder of the present invention, the air blowing means is operated while the heating of air by the heater is stopped, so that the heater can be cooled simply and efficiently. [Brief description of the drawings]

[0010] [Figure 1] 1 is a conceptual diagram showing an example of an image forming system including a paper feeder of the present invention. [Diagram 2] FIG. 2 is a conceptual diagram illustrating an internal configuration of a paper feeding device. [Diagram 3] FIG. 2 is a block diagram showing a control configuration of the paper feeding device. [Figure 4] FIG. 4 is a flowchart showing the blowing operation of the blower mechanism. [Diagram 5] FIG. 4 is a flow chart showing a cooling operation of the heater. [Figure 6] 13 is a conceptual diagram showing the movement of the louver when the heater is cooled. FIG. [Figure 7] 13 is a conceptual diagram showing a louver moving operation when cooling a heater in another embodiment. FIG. 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 paper feeding apparatus 5 connected to the image forming apparatus 2. The image forming apparatus 2 forms an image in an image forming section 7 on a sheet supplied from one of an upper cassette 10, a lower cassette 11, or the paper feeding apparatus 5 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] 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 the storage 20. The storage 20 is supported by the housing 50 so as to be able to be pulled out via the slide rails 21a and 21b. The feeding mechanism 30 includes a feed roller 31, a feed roller 32, and a separation roller 33, which are driven by a sheet feed motor MT1. The sheets stored in the storage 20 are fed by the feed roller 31, and are separated and fed one by one by the feed roller 32 and the separation roller 33. In addition, a pair of conveying rollers 34a and 34b are provided downstream of the feeding mechanism 30 in the sheet feeding direction, and the sheets fed by the pair of conveying rollers 34a and 34b are supplied to the image forming device 2.

[0017] 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 on the lower side inside 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.

[0018] 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.

[0019] 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.

[0020] A first blower mechanism 40 as a first blower means arranged downstream in the sheet feed direction and a second blower mechanism 50 as a second blower means 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 blower 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.

[0021] 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.

[0022] 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 and a heater 43 arranged in the first duct 41. The exhaust port 41b of the first duct 41 is connected to a first exhaust opening 23a provided in the first side regulating plate 23, and is arranged at a position where air is blown onto the upper part of the sheets loaded on the stacking tray 53. The blowing fan 42 arranged in the first duct 41 rotates 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 42 heated by the heater 43 is blown by the blowing fan 42 from the exhaust port 41b onto the side of the sheets.

[0023] Furthermore, a first louver 44 is provided on the air outlet 41b side in the first duct 41 of the first blowing mechanism 40 as a deflection means for changing the blowing range and blowing direction of the air blown out from the air outlet 41b. The first louver 44 is configured to be attached to a rotating shaft 44a at one end on the back side of the first duct 41 and to be rotated by the rotation of the rotating shaft 44a. The first louver 44 moves to an open position (see FIG. 6(a)) where the air outlet 41b is fully opened so that the air can be blown to the end of the sheet on the stacking tray 22, and a blocking position (see FIG. 6(b)) where the part of the air outlet 41b facing the end of the sheet is blocked so that the air cannot be blown to the end of the sheet. Then, the cooling operation is performed when the first louver 44 is in the blocking position. In the blocking position, the first louvers 44 block the portion of the air outlet 41b facing the edge of the sheet as shown in Fig. 6(b) and direct the air to be blown upward above the uppermost sheet. That is, during the cooling operation, the first louvers 44 move from the open position to the blocking position, and the direction of the air is deflected. Also, the first louvers 44 are controlled to swing up and down at a constant cycle when blowing air to separate the sheets. This creates a difference in the pressure of the air blown to the edge of the sheet, and the direction of the air changes, improving the accuracy of separating the sheets.

[0024] 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 second duct 51 onto the side of the sheets stacked on the stacking tray 22 from the exhaust port 51b.

[0025] The second blowing mechanism 50 is also provided with a louver 45. This 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, the second louver 45, like the first louver 44 of the first blowing mechanism 40, also generates varying strengths in the wind pressure of the air blown against the edge of the sheets, thereby changing the direction of the air.

[0026] 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 heater temperature.

[0027] Fig. 3 is a block diagram of a control system of the sheet feeding device 5 shown in Fig. 2. The sheet feeding device 5 is provided with a control unit 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 the 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, and a thermistor S3 for measuring the temperature of the heater 41. Furthermore, the printer is provided 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 M2 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 heats the air to be blown, first and second fan motors MT4 and MT5 which drive first and second blower fans 42 and 52 which blow air to blow air onto the sheets, and a rotation motor MT6 which rotates the first and second louvers 44 and 45.

[0028] The control unit 100 controls the driving of the sheet feed motor MT1, the conveying motor MT2, the lifting motor MT3, the heater 43, and the first and second blower fans 42 and 52 based on various information from the operation unit 101, to which information on the size and material of the sheet, the type of sheet such as special paper, and the printing mode such as double-sided printing, single-sided printing, reduced printing, and enlarged printing is input, and on the basis of the results of detection and measurement by the upper surface detection sensor S1, the lower limit detection sensor S2, and the thermistor S3. The control unit 100 also transmits information on errors due to damage to parts, lifting failure of the stacking tray 22, paper feed failure, etc. to the display unit, and notifies the display unit. In this embodiment, the control unit 100 is provided in the sheet feed device 5, but may be provided in the image forming device 2 or the image reading device 3. Furthermore, the operation unit 101 and the display unit 102 may also be attached to the image forming device 2 or the image reading device 3.

[0029] 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.

[0030] 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.

[0031] Next, the blowing operation by the first blowing mechanism equipped with the heater 43 will be described with reference to the operation flow chart of Fig. 4. The blowing operation is performed when it is confirmed that the storage 20 is closed and when a paper feed command is received. The blowing operation is also performed during the sheet feeding operation, and the blowing operation stops when the sheet feeding operation is completed. However, if the heater 43 is operating, the heater 43 continues to operate even when the blowing of the air stops, and continues to heat the air in the first duct 41.

[0032] In the above description, the air blowing operation is ended when the paper feed operation is ended, but the air blowing operation may be executed after the paper feed operation is ended. In other words, the air blowing operation may be stopped and then executed again.

[0033] In the air blowing operation, first, sheet information such as the paper quality, paper thickness (basis weight), size, etc. of the sheet is acquired (ST01). This sheet information is input by the user operating the operation unit, and whenever the type of sheet is changed, the user operates the operation panel to input new information.

[0034] Based on the input sheet information, it is determined whether or not air clearance is required (ST02). If it is determined that air clearance is required, it is determined whether or not the heater 43 is required, that is, whether or not air clearance using hot air is performed (ST03). If it is determined that the heater 43 is not required, the cooling operation of the heater 43 is executed (ST10). On the other hand, if it is determined that the heater 43 is required, it is confirmed whether or not the set temperature of the heater 43 has been changed (ST04). For this determination, a temperature table based on the sheet information is stored in advance in the ROM of the control unit 100, and the set temperature is obtained from the temperature table based on the sheet information obtained in step (ST01), and compared with the previous set temperature to determine whether or not the set temperature has been changed.

[0035] When it is confirmed that the set temperature of the heater 43 has been changed, the thermistor S3 detects the heat temperature of the heater 43 (ST05). Then, from this measured value, it is determined whether or not cooling of the heater 43 is necessary. Specifically, the detected heat temperature of the heater 43 is compared with the set temperature, and if the detected heat temperature of the heater 43 is higher than the set temperature, it is determined that cooling of the heater 43 is necessary. On the other hand, if the detected heat temperature of the heater 43 is equal to or lower than the set temperature, it is determined that cooling of the heater 43 is not necessary.

[0036] If it is determined that cooling of the heater 43 is necessary, a cooling operation of the heater 43 is executed (ST10). On the other hand, if cooling of the heater 43 is not necessary, a set temperature adjustment is executed. Then, when this temperature adjustment is completed, the first blower fan 42 is operated to blow air through the first duct 41 toward the side of the sheet, and the sheet is separated (ST07 to ST09).

[0037] In the temperature adjustment operation of the heater 43, if the temperature measured by thermistor S3 is equal to or lower than the set temperature, the heater 43 is turned ON, and the adjustment is completed when the thermistor S3 detects that the temperature has reached the set temperature. On the other hand, if the temperature setting has not been changed (ST04) or after the cooling operation, the temperature measured by thermistor S3 is checked, and if it is different from the set temperature, the heater 43 is turned ON or OFF to adjust the temperature closer to the set temperature. In this way, the first blower fan 42 is operated with the heater 43 stopped to cause air to flow along the first duct 41 until the temperature of the heater 43 reaches a predetermined temperature lower than the temperature measured by thermistor S3.

[0038] Here, the cooling operation of the heater 43 is performed by operating the first blower fan 42 while stopping the heater 43 to cause air to flow along the duct 41 until the temperature of the heater 43 reaches a predetermined temperature lower than the temperature measured by thermistor S3.

[0039] That is, here, as a cooling means, the first blower fan 42 blows air while the heater 43 is turned off. 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 port 41a. The air taken in from the intake port 41a flows in the first duct 41 toward the outlet 41b while coming into contact with the heat radiator 43 of the heater 43, and cools the heater 43.

[0040] FIG. 5 is an operation flow chart showing the cooling operation. The cooling operation will be described in detail with reference to FIG. 5. First, the set temperature adjustment of the heater 43 is stopped, and the heater 43 is stopped (OFF) (ST11). After that, the rotation motor MT6 is driven in the reverse direction to rotate the first louver 44 upward (ST12). When the rotation motor MT6 is driven a predetermined amount, the rotation motor MT6 is stopped, and the rotation of the first louver 44 is stopped (ST13 to ST14). As a result, the first louver 44 moves from the open position in which the air outlet 41b is fully opened as shown in FIG. 6(a) to the blocking position as shown in FIG. 6(b) and stops there. In the blocking position, the first louver 44 blocks the portion of the air outlet 41b below the upper surface position of the sheet, and opens the portion above the upper surface position of the sheet.

[0041] In this state, the first blower fan 42 is operated (ON) to start cooling (ST15). This allows the heater 43 to be cooled to the set temperature as the air flowing from the intake port 41a toward the exhaust port 41b passes through the heater 43. Furthermore, since the louvers 44 have moved to the blocking position, the warm air at the beginning of the cooling operation is blown out from the upper part of the exhaust port 41b to the upper side of the sheet as shown in FIG. 6(b), and is not blown onto the edge of the sheet.

[0042] Then, when the heater temperature measured by the thermistor S3 reaches the set temperature, the blower fan 42 is stopped (OFF) to end the cooling (ST16 to ST17). After that, the rotation motor MT6 is driven in the forward direction to rotate the louver 44 downward (ST18). When the rotation motor MT6 is driven a predetermined amount, the rotation motor MT6 is stopped to stop the rotation of the first louver 44 (ST19 to ST20). As a result, the first louver 44 is returned from the blocking position to the open position, and the end of the sheet is brought into a state where air is blown. Note that the above-mentioned predetermined drive amount of the rotation motor MT6 is a drive amount equivalent to the distance between the open position and the blocking position. In other words, it is a drive amount required for the first louver 44 to rotate from the open position to the blocking position.

[0043] Here, the set temperature in step (ST16) when heater 43 is not required in step (ST03) of the air blowing operation can be set by an environmental sensor S4 provided in sheet feeding device 5. When such an environmental sensor S4 is used, the set temperature is automatically set to a temperature obtained by adding a certain value to the measured temperature in storage 51. The set temperature in this case may be a predetermined temperature (for example, 20° C. or lower).

[0044] In the above embodiment, the air volume of the first blower mechanism 40 is set to an air volume suitable for sheet handling, and the heater 43 is cooled by this set air volume during the cooling operation. However, the air volume may be set to be larger than the set air volume suitable for sheet handling during the cooling operation of the heater 43. Furthermore, if the rotation speed of the first blower fan 42 during the cooling operation is set to the maximum, it is possible to cool the heater 43 in a shorter time.

[0045] Next, other embodiments will be described. In the above-mentioned embodiment, the first louver 44 is moved to a blocking position where the part of the air outlet 41b facing the end of the sheet is blocked to prevent the hot air during cooling from being blown onto the end of the sheet, but a deflection mechanism may be provided that blocks the air outlet 41b and opens a part of the first duct 41 to deflect the direction in which the air is blown out, so that the hot air during cooling is not blown onto the end of the sheet.

[0046] 7 is a schematic diagram showing the configuration and operation of another embodiment. The deflection mechanism 60 includes the first louver 44 that rotates between a first position for guiding air toward the air outlet 41b and a second position for guiding air toward the open opening 61a, a rotation motor MT6 for rotating the first louver 44, and a plurality of gears (not shown) as a transmission member for transmitting the drive of the rotation motor MT6 to the rotation shaft 44a of the first louver 44. The deflection mechanism 60 further includes a guide member 61 that rotates between a guide position for forming a part of the first duct 41 to guide air toward the air outlet 41b and an opening position for opening a part of the first duct 41 to form an opening 65 for blowing out air, and three gears 62, 63, and 64 for transmitting the drive of the rotation motor MT6 to the rotation shaft 61a of the guide member 61 via the rotation shaft 44a of the first louver 44.

[0047] During the cooling operation, the rotary motor MT6 is driven in the reverse direction to move the first louver 44 from the first position to the second position and move the guide member 61 from the guide position to the opening position, thereby discharging air from the opening 65 to the outside of the first duct 41. This makes it possible to prevent the hot air at the beginning of the cooling operation from being blown onto the edge of the sheet.

[0048] Specifically, in steps 12 (ST12) to 14 (ST14) of the cooling operation in Fig. 6, when the rotary motor MT6 is driven in the reverse direction by a predetermined amount and then stopped, the first louver 44 rotates from the first position to the second position and the guide member 61 rotates from the guide position to the opening position (see Figs. 7(a) and 7(b)). In this state, when the first blower fan 42 is turned ON to start cooling the heater 43, the air (hot air) heated by the heater 43 is guided to the opening 65 by the first louver 44 as shown in Fig. 7(b) and blown out of the first duct 41 from the opening 65, without being blown onto the edge of the sheet.

[0049] In the first step, in steps 18 (ST18) to 20 (ST20) in FIG. 6 when the heater 43 reaches the set temperature and cooling is completed, the rotary motor MT6 is driven forward a predetermined amount and then stopped, and the louver 44 rotates from the second position to the first position, and the guide member 61 rotates from the opening position to the guide position (see FIG. 7(b) and FIG. 7(a)). As a result, as shown in FIG. 7(a), the guide member 61 closes the opening 65, and air is blown out from the blowout port 41b. Note that the predetermined drive amount of the rotary motor MT6 in the other embodiments is a drive amount equivalent to the distance from the first position to the second position. In other words, it is a drive amount required for the louver 44 to rotate from the first position to the second position.

[0050] According to the above embodiment, the first blower fan 42 is driven with the heater 43 turned off, so that the temperature of the heater 43 in the first duct 41 can be reduced in a short period of time.

[0051] In addition, by moving the louvers 44 to the shielding position when the heater 43 is cooling, it is possible to prevent the hot air during cooling from being blown onto the sheet. This makes it possible to eliminate printing unevenness that occurs when hot air of a temperature higher than the appropriate temperature for the type of sheet is blown onto the sheet. [Explanation of symbols]

[0052] 2 Paper feeder 5. Paper feeder 20 Storage 23, 24 A pair of side regulating plates 23, 24 30 Feeding mechanism 22 Loading Tray 40 First blower mechanism 42 Blower fan 42 41 Duct 41a Inlet 41b Air outlet 42 Blower fan 43 Heater 44 Louver MT6 Rotary motor MT6 S3 Thermistor

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 to an end portion of the sheets on the stacking tray, and a heater for heating the air blown by the blowing means, A sheet feeding device characterized by being provided with a cooling means for operating the air blowing means while the heater is stopped to cool the heater, and a deflection means for blowing air in a direction that avoids the edges of the sheet when cooling the heater with the cooling means.

2. 2. The sheet feeding device according to claim 1, wherein the deflection means deflects the direction of air blown by the blowing means into a first direction in which the air is blown toward the edge of the sheet, and into a second direction in which the air is blown avoiding the edge of the sheet.

3. a temperature detection means for detecting a temperature of the heater; 2. The sheet feeding device according to claim 1, wherein the cooling means operates the air blowing means with the heater stopped until the temperature of the heater detected by the temperature detection means falls to a predetermined temperature or lower.

4. 2. The sheet feeding device according to claim 1, wherein the blowing means comprises a duct having an intake port and an exhaust port, and a blower fan arranged within the duct to draw in air through the intake port and blow out the air from the exhaust port, and the heater is arranged within the duct.

5. The air blowing means includes a duct having an air outlet, and a blower fan that blows air along the duct and blows the air out from the air outlet, 3. The sheet feeding device according to claim 2, wherein the first direction by the deflection means is a direction in which air is blown out of the air outlet toward an edge of the sheets on the stacking tray, and the second direction is a direction in which air is blown out of the air outlet toward a position above the top sheet on the stacking tray.

6. the air blowing means includes a duct having a first air outlet provided at a position for blowing air toward an end of the sheets on the stacking tray, and a second air outlet provided at a position for blowing air away from the end of the sheets on the stacking tray; 3. The sheet feeding device according to claim 2, wherein the first direction by the deflection means is a direction in which air is blown toward the first air outlet, and the second direction is a direction in which air is blown toward the second air outlet.

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