JP2010030779A - Sheet feeder and image forming device - Google Patents

Abstract

A paper feeding device and an image that can effectively assist air-assisted separation with a simple configuration, obtain a good separation property, perform stable paper feeding, and prevent water droplets from adhering to the sheet. A forming apparatus is provided.
SOLUTION: A sheet storage portion 8 for storing a sheet bundle (not shown), a sheet feeding means 9 for feeding a sheet, a blowing means (not shown) for blowing air to the sheet, and a feeding from the blowing means. And a blower port 21 through which the blown air is sent, wherein the blower port 21 is provided so as to face an upper end portion of the sheet bundle, and conveys a sheet to the blower port 21. First heating means 51 a and 51 b for heating the sheet are provided at the same height as the surface P and on the lateral side of the air blowing port 21.
[Selection] Figure 4

Description

  The present invention relates to a sheet feeding device and an image forming apparatus including the sheet feeding device.

  In various image forming apparatuses such as a printer, a copier, and a facsimile, a sheet feeding apparatus (sheet feeding) that feeds sheets one by one from a sheet bundle stored in a sheet storage unit and supplies the sheet to the image forming unit / printing unit. In recent years, with the diversification of sheets, coated paper such as coated paper and art paper, and film paper such as OHP are often used. However, for example, coated paper has characteristics such as high smoothness, low air permeability, and high hygroscopicity, so that the adhesion between sheets tends to increase in the laminated state, and this tendency becomes remarkable in a high humidity environment. For this reason, separability is poor compared to plain paper, and double feeding and non-feeding are likely to occur during paper feeding.

  As a countermeasure, recently, by providing an air outlet on the side fence for regulating the lateral position of the sheet bundle in the width direction, blowing air from the fan connected to the air outlet, and blowing the air to the side of the sheet bundle In many cases, a sheet feeding device equipped with a so-called air assist separation mechanism is provided so that air enters between sheets before feeding and assists separation. However, simply ejecting air may not be able to be separated sufficiently in a state of high adhesion between sheets in a high humidity environment, and may cause problems such as double feeding and non-feeding during sheet feeding. .

  In order to reduce the adhesion between sheets in this high humidity environment, it is known that there is an effect by lowering the relative humidity by increasing the temperature. The heater is used to increase the environment of the sheet storage section or to warm the air. It is known that it is effective by making it wind.

  In Patent Document 1, air heating means (heater) is provided, air assist separation is performed by the wind of a fan blown to the heater, that is, warm air, and the heater temperature is controlled by humidity detected by a humidity sensor provided in the vicinity of the fan. It has been proposed. However, in this configuration, a heater with a large output is required depending on the air temperature to be blown, and it is assumed that the efficiency is low in terms of power. In addition, since the relative humidity is reduced only on the side of the sheet and the sheet storage part remains highly humid, for example, if water droplets are attached to the transport roller or the sheet guide part, the paper feeding performance becomes unstable. There is a problem that water droplets adhere to the sheet.

  Further, Patent Document 2 proposes that a heating element is installed on the side fence and the front fence in order to warm the upper end portion of the sheet bundle stored in the sheet storage portion, and the relative humidity at the upper end portion of the sheet bundle is lowered. . However, in this configuration, since the sheet storage portion remains highly humid, there is a problem similar to the case of Patent Document 1.

  Patent Document 3 discloses a configuration in which a heating element is installed above a sheet bundle and the sheet storage unit and the sheet feeding unit are warmed to lower the relative humidity. However, this configuration has a problem that the relative humidity at the upper end of the sheet bundle does not decrease, so that it is not sufficient for air-assisted separation, and a large-scale device is required to obtain the effect.

  The present invention solves the above-described problems in a conventional sheet feeding apparatus or image forming apparatus, and effectively assists air-assisted separation with a simple configuration to obtain good separation and perform stable paper feeding. It is another object of the present invention to provide a sheet feeding apparatus and an image forming apparatus in which water droplets do not adhere to the sheet.

According to the present invention, there is provided a sheet storage unit that stores a sheet bundle, a sheet feeding unit that feeds a sheet from the sheet bundle, a blowing unit that blows air to the sheet, and a feeding unit that sends the sheet from the blowing unit. A sheet feeding device including a blower port through which the air is sent, wherein the blower port is provided to face the upper end of the sheet bundle, and a sheet conveying surface with respect to the blower port The problem is solved by having a first heating means that heats the sheet at substantially the same height and on the lateral side of the blower opening.
Further, it is preferable that a second heating means for heating the upper part of the seat is provided above the blower opening.

  Further, according to the present invention, there is provided a sheet storage unit that stores a sheet bundle, a sheet feeding unit that feeds a sheet from the sheet bundle, a blowing unit that blows air to the sheet, and the blowing unit. A sheet feeding device including a blowing port through which air sent from the sheet is sent, wherein the blowing port is provided to face an upper end portion of the sheet bundle, and conveys a sheet to the blowing port. A second heating means that is substantially the same height as the surface and has a first heating means for heating the sheet on the lateral side of the blower opening, and heats the upper part of the sheet above the blower opening. It is solved by providing.

  In addition, when the guide fence has a guide fence that guides the side edge of the sheet bundle, the air blowing port and the first heating unit, or the air blowing port and the first and second heating unit are provided on the guide fence. preferable.

Further, it is preferable that the first heating means is operated before the air blowing by the air blowing means.
Further, it is preferable that the second heating unit is provided at a position where the position of the leading end portion in the sheet conveying direction is substantially equal to the position of the leading end portion in the sheet conveying direction of the first heating unit.

Further, it is preferable that the first heating means is arranged so as to border the periphery of the air blowing port.
Further, it is preferable that the first heating unit is provided so as to heat the sheet storage portion and the upper end portion of the sheet bundle.

It is preferable to have a control means for controlling the amount of heat generated by each heating means.
The storage unit temperature and humidity detection means for detecting the temperature and humidity in the sheet storage unit, and the sheet temperature and humidity detection means for detecting the temperature and humidity of the uppermost surface of the sheet bundle stored in the sheet storage unit, Preferably, the second heating unit is controlled according to the detection result of the storage unit temperature / humidity detection unit, and the first heating unit is controlled according to the detection result of the sheet temperature / humidity detection unit.

  Further, the control unit controls the first heating unit and the second heating unit so that the humidity detected by the storage unit temperature / humidity detection unit and the sheet temperature / humidity detection unit is a predetermined value or less. preferable.

The predetermined value is preferably 45%.
Further, it is preferable to control the operation of the sheet feeding means in accordance with detection results of the storage section temperature / humidity detection means and the sheet temperature / humidity detection means.

Further, it is preferable to provide a sheet upper limit position optimization mechanism that maintains the upper end position of the sheet bundle at a predetermined position.
In addition, according to the present invention, the above problem is solved by an image forming apparatus including the sheet feeding device according to any one of claims 1 to 9.

  According to the sheet feeding apparatus of the present invention, it is possible to heat the top several sheets of the stacked sheet bundle from the side. By performing this heating, the side edge portion of the sheet is dehumidified, thereby making it easier to feed air between the sheets. In particular, the side edges of the upper several sheets are slightly curled into a waved shape by heating. This curl creates a gap between the sheets, and air can be blown into the entire sheet (the entire sheet surface) from the gap, reducing the adhesion between the sheets and improving the paper handling effect. In addition, stable sheet feeding by reliable sheet separation can be realized by air assist separation.

  According to the configuration of the second aspect, since the second heating means provided above the blower opening is provided at a position not hidden by the sheet bundle, the space above the sheet bundle can be heated and dehumidified. As a result, it is possible to dehumidify the sheet feeding means through the space above the sheet.

  With the configuration of the third aspect, by providing the first heating means and the second heating means, it is possible to realize stable paper feeding by reliable sheet separation by air-assisted separation, and feeding through the space above the sheet. It becomes possible to dehumidify the paper means.

  According to the configuration of the fourth aspect, by providing the air blowing port and each heating unit on the guide fence, the air blowing port and each heating unit can be easily installed at a required position near the upper end of the sheet bundle.

  According to the configuration of claim 5, since the first heating means is operated before the blowing, the heating is performed before the blowing, and the blowing can be performed in a state where the sheet is easily separated, and the double feeding and the non-feeding are further performed. It can be surely prevented.

  According to the configuration of the sixth aspect, the second heating unit is disposed close to the downstream side in the sheet conveying direction, and the second heating unit is disposed near the sheet feeding unit, so that the sheet feeding unit and its The relative humidity in the vicinity can be reduced, and more stable paper feeding can be performed.

According to the configuration of the seventh aspect, heating and dehumidification (reduction in relative humidity) in the vicinity of the air blowing port can be performed with one heating means.
According to the configuration of the eighth aspect, the relative humidity of the sheet storage unit including the sheet feeding unit can be reduced, the relative humidity of the upper end portion of the sheet bundle can be reduced, and the sheet-to-sheet adhesion can be reduced to assist sheet separation. Even with coated paper with strong adhesion in a high humidity environment, air assist separation can function well, preventing double feeding and non-feeding.

  According to the configuration of the ninth aspect, it is possible to generate heat as much as necessary according to the sheet type, sheet thickness, or sheet storage unit environment, and it is possible to efficiently reduce the relative humidity while suppressing unnecessary heating. .

  According to the configuration of claim 10, it is possible to control the humidity above the sheet bundle at the top of the sheet bundle and the sheet storage unit, and even with coated paper such as coated paper or art paper that generates high adhesion in a high humidity environment. Since the adhesive force does not increase, the sheet separation function by air assist can be improved and stable paper feeding can be performed.

  According to the structure of the eleventh aspect, the humidity above the sheet bundle in the uppermost part of the sheet bundle and the sheet storage unit can be kept below a certain level, so that the sheet separation function by air assist can be enhanced.

  According to the configuration of claim 12, by setting the humidity above the sheet bundle at the top of the sheet bundle and the sheet storage portion to 45% or less, the frequency of double feeding of coated paper can be greatly reduced. However, reliable and stable paper feeding can be performed.

  By controlling the operation of the sheet feeding means according to the detection results of the storage unit temperature / humidity detecting means and the sheet temperature / humidity detecting means, the sheet feeding means in a high humidity environment can be prevented and stabilized. Paper can be fed.

  According to the structure of the fourteenth aspect, by appropriately maintaining the upper end position of the sheet bundle, it is possible to always optimally heat the top several sheets of the sheet bundle, and to perform the air assist separation well and perform the overlap. Sending and non-feeding can be prevented.

  According to the image forming apparatus of the fifteenth aspect, by providing a sheet feeding device that exhibits a good air assist separation function, even if the sheet has a strong adhesion such as a coated paper or an OHP film, the sheet can be reliably separated. It is possible to prevent feeding and non-feeding, and it is possible to realize a highly functional image forming apparatus with excellent productivity by stable and reliable paper feeding.

1 is a system configuration diagram of an image forming apparatus including a sheet feeding device according to the present invention. FIG. 3 is a perspective view illustrating an internal configuration of a sheet feeding device. It is a perspective view which shows the main characteristic parts of a paper feeder. It is a figure which shows the characteristic position and shape of an air jet nozzle and a 1st and 2nd heat generating body. It is a figure which shows the example from which the position of a 2nd heat generating body differs. FIG. 6 is a longitudinal sectional view of a sheet feeding device, and is a diagram illustrating an effect of a sheet upper end portion by a heating element. It is a schematic diagram explaining a paper separation effect. It is a perspective view which shows the main characteristic parts of the paper feeder of 2nd Example. It is a figure which shows the characteristic position and shape of an air jet nozzle and a heat generating body in the paper feeder. It is a perspective view which shows the main characteristic parts of the paper feeder of 3rd Example. It is a figure which shows the characteristic position and shape of the air jet nozzle 21 in the side fence 13, and the 1st and 2nd heat generating body 51,52. FIG. 6 is a longitudinal sectional view of a sheet feeding device, and is a diagram illustrating an effect of a sheet upper end portion by a heating element. FIG. 6 is a vertical cross-sectional view of the sheet feeding device, illustrating a state of moisture absorption / release of a sheet bundle. It is a graph which shows the relationship between the humidity in coated paper, and the presence or absence of double feeding.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a system configuration diagram of an image forming apparatus provided with a sheet feeding device according to the present invention. An image forming apparatus 1 shown in FIG. 1 includes an image forming apparatus body 2 and a sheet feeding device (sheet feeding apparatus) 5 connected to one side surface of the image forming apparatus body 2. The image forming apparatus main body 2 can adopt, for example, an electrophotographic system, and its configuration and image forming operation are well known, so that the description thereof will be omitted and the sheet feeding apparatus 5 will be mainly described.

FIG. 2 is a perspective view showing an internal configuration of the sheet feeding device.
As shown in FIG. 2, the sheet feeding device 5 feeds the sheet storage unit (sheet feeding tray) 8 having the bottom plate 6 on which the sheet bundle is stacked and the uppermost sheet of the sheet bundle one by one to main body of the image forming apparatus. And a paper feeding unit (paper feeding means) 9 for feeding paper 2.

  In the paper supply unit 9, a paper supply roller 11, a separation roller 12a, and a return roller 12b are arranged. These rollers 11, 12a and 12b are driven to rotate at respective preset paper feed timings. Further, in the sheet feeding tray 8, side fences 13 are provided on both sides for regulating the width direction (direction perpendicular to the sheet feeding direction) side of the sheet bundle stacked on the bottom plate 6, and the rear end face is located behind the sheet bundle. There is an end fence 14 that regulates.

  The upper limit of the sheet bundle is detected by a sensor 15 composed of a photo interrupter. The sensor 15 detects the sheet feeding position, and the bottom plate so that the sheet feeding position is always constant even when the remaining amount of sheets is low. The sheet feeding position is controlled by moving 6 up and down by a lifting motor M. In this way, in order to keep the paper feed separation condition constant, the sheet upper limit position is always optimized so that the paper feed position is always constant even when the sheet stacking amount increases or decreases.

  The actuator 16 for operating the sensor 15 is connected to the sheet feeding roller 11 and the separation roller 12a, and the filler disposed at the end of the actuator 16 shields the sensor 15 so that the upper limit of the sheet is always set. And the position of the paper feed roller 11 is kept constant. Further, even if the bottom plate 6 rises in conjunction with the decrease in the sheet stacking amount, this position detection is performed by the actuator 16. The sheet storage unit 8 is configured to be detachable from the main body of the sheet feeding device 5, and when the user sets a sheet in the sheet storage unit 8, the sheet storage unit 8 is pulled out.

  FIG. 3 is a perspective view showing main features of the sheet feeding device, as viewed from the side opposite to FIG. In the drawing, the exterior cover (front cover) of the paper feeding device 5 is omitted. 4 and 5 are diagrams showing the characteristic positions and shapes of the air jet port 21 and the first and second heating elements 51 and 52 in the side fence 13. FIG. 6 is a longitudinal sectional view of the paper feeding device 5 and shows the effect of the upper end portion of the sheet by the heating element. FIG. 7 is a schematic diagram for explaining the paper separation effect.

  As shown in FIG. 3, a blower fan 20 is attached to the outside of each side fence 13, and an air outlet (nozzle) 21 through which air generated by the blower fan 20 is ejected opens on the inner side surface of the side fence 13. As shown in FIG. 4, the air ejection port 21 is disposed at a position where the height of the upper edge 21a is higher than the sheet passing path P of the sheet fed by the sheet feeding unit 9, and the lower edge 21b passes through. By being arranged at a position lower than the paper path P, air can be sprayed onto the upper end of the sheet bundle.

  As shown in FIGS. 4 and 5, heating elements 51 a, 51 b and 52 are mounted on the side surfaces of the side fences 13 around the air outlet 21. The heating elements 51 and 52 are, for example, resistance heating elements, and can generate heat by electric power supplied from a power supply unit (not shown).

  The heating elements 51a and 51b, which are first heating elements, are provided at substantially the same height as the sheet passing path P that is the sheet conveying surface and on both sides in the horizontal direction with respect to the air outlet 21. It has been. In addition, the heating element 52 as the second heating element is provided above the air outlet 21. In the arrangement example of FIG. 4, the second heat generating body 52 is provided directly above the air ejection port 21, and both ends of the second heat generating body 52 are placed above (overlap) the left and right first heat generating bodies 51 a and 51 b. In the arrangement example of FIG. 5, the second heating element 52 is arranged close to the downstream side in the sheet conveying direction, and the front end position of the second heating element 52 is substantially the same as the front end position of the first heating element 51 (51a). It is the same position. The rear end of the heating element 52 is located in the middle of the air outlet 21. The arrangement of the first heating elements 51a and 51b is the same. In addition, the structure which provides only the 1st heat generating body 51 (51a, 51b) without providing the 2nd heat generating body 52 is also possible.

  Since the first heating elements 51a and 51b are located on the side of the air outlet 21, the upper end of the sheet bundle at the same position as the sheet passing path P can be warmed. Therefore, it is possible to heat the top several sheets of the stacked sheets from the side on the sheet conveying surface. Thereby, the side edge part of a sheet | seat is dehumidified and it becomes easy to send air between sheets. In particular, the sheet side edge slightly curls into a wavy shape by heating. When the curl is generated, a gap is formed between the sheets, and air can be blown into the entire sheet from the gap (see FIGS. 6 and 7). Therefore, the adhesion between sheets is reduced, the paper separation effect by air is improved, and stable paper feeding by reliable sheet separation is realized by air assist separation.

  In addition, since the second heating element 52 is located above the air ejection port 21, it is located above the sheet passing path P. Therefore, the sheet storage unit 8 above the sheet bundle can be warmed, and the sheet feeding unit 11 including the sheet feeding roller 11, the separation roller 12a, the return roller 12b, and the guide plate can be warmed to reduce the relative humidity. Paper performance can be stabilized and water droplets due to high humidity on the roller surface and the guide plate are eliminated, for example, so that water droplets can be prevented from adhering to the sheet.

  As shown in FIG. 5, the second heating element 52 approaches the paper feeding unit 9 by being positioned on the downstream side in the sheet conveying direction, and the relative humidity of the paper feeding unit is further lowered. The performance can be stabilized.

  The heating elements 52a, 52b and 51 can each control the amount of heat generated by a control means (not shown). For example, the relative humidity of the sheet storage unit 8 and the relative humidity of the upper end of the sheet can be appropriately reduced by generating heat as much as necessary according to the sheet type, the sheet thickness, or the environment of the sheet storage unit 8. The control of the heating element can be controlled by the control unit of the image forming apparatus main body 2 to which the sheet feeding device 5 is mounted.

  As described above, the sheet feeding device of the present invention has the first and second heating elements 51 and 52 around the air outlet 21 to effectively assist air assist separation with a simple configuration. Therefore, it is possible to obtain a stable separation and to feed stably. Further, since the paper feeding means can be dehumidified, it is possible to prevent water droplets from adhering to the sheet.

  Furthermore, by controlling the heat generation amount of the first and second heating elements 51 and 52 according to the sheet type, sheet thickness, or the environment of the sheet storage unit 8, the sheet storage unit and the stacked sheet bundle upper end portion are controlled. The relative humidity can be lowered appropriately, and wasteful energy consumption can be prevented.

Next, a second embodiment of the paper feeder will be described.
FIG. 8 is a perspective view showing main features of the paper feeder of the second embodiment. FIG. 9 is a diagram showing the characteristic positions and shapes of the air jets 21 and the heating elements 55 provided on the side fence 13 in the paper feeding device. The paper feeding device of the second embodiment is the same as the paper feeding device of the first embodiment described above except for the heating element 55 provided around the air outlet 21. explain.

  As shown in FIGS. 8 and 9, in the paper feeding device of this example, a heating element 55 is provided so as to border the air ejection port 21. Since the heating element 55 is provided so as to border the air ejection port 21, the heating element is provided at least on the side of the air ejection port 21. The heating element 55 is, for example, a resistance heating element, and can generate heat by electric power supplied from a power supply unit (not shown).

  In this example, since the heating element 55 has a shape that borders the air outlet 21, the sheet storage unit 8 above the sheet bundle can be warmed, and therefore, the sheet feeding roller 11, the separation roller 12 a, the return roller 12 b, and the guide plate Since the relative humidity can be lowered by heating the entire sheet feeding unit including the sheet feeding unit 9 including the sheet feeding path P, the relative humidity of the sheet upper end can be increased. Is reduced to reduce the adhesion between the sheets, and it becomes easier to blow out air between the sheets and to separate them.

  The heating element 55 can control the amount of heat generated by the control means. For example, the heating element 55 generates heat as much as necessary according to the sheet type, the sheet thickness, or the environment of the sheet storage unit 8, so that the relative humidity of the sheet storage unit 8 and the sheet The relative humidity at the upper end can be lowered appropriately. The control of the heating element can be controlled by the control unit of the image forming apparatus main body 2 to which the sheet feeding device 5 is mounted.

  Next, a third embodiment of the paper feeder will be described. The third embodiment has the same basic configuration as the first embodiment described above, and the arrangement of the first and second heating elements 51 and 52 is the same as that described in FIG. The overlapping description is omitted.

  FIG. 10 is a perspective view showing main features of the paper feeder of the third embodiment. FIG. 11 is a diagram showing the characteristic positions and shapes of the air outlet 21 and the first and second heating elements 51 and 52 in the side fence 13. FIG. 12 is a longitudinal sectional view of the sheet feeding device, and shows the effect of the sheet upper end portion by the heating element. FIG. 13 is a longitudinal sectional view of the sheet feeding device, and is a view for explaining the moisture absorption / release state of the sheet bundle.

  As shown in FIG. 13, the sheet bundle mounted in the sheet storage unit (paper feed tray) 8 is easily affected by the outside air at the top and side edges, and when stored in the sheet storage unit 8, the storage unit If the humidity of the sheet bundle 8 is different from that of the sheet bundle, moisture absorption / release occurs at the uppermost part and the side end of the sheet bundle. In this phenomenon, for example, when the sheet storage portion 8 is higher in humidity than the sheet bundle, moisture absorption occurs at the top and side edges of the sheet bundle, and high adhesion occurs in coated paper such as coated paper and art paper. End up. This phenomenon is as follows: 1) The humidity difference between the uppermost sheet bundle fed by the sheet feeding unit 9 and the sheet storage unit is eliminated, and no moisture absorption / release occurs. 2) Both the sheet storage unit 8 and the sheet bundle are humidified below a certain level at which high adhesion force is not generated. This can be prevented by implementing the following two points.

  Therefore, in the third embodiment, as shown in FIGS. 10 and 11, a sheet temperature / humidity detection sensor 54 for detecting the sheet temperature / humidity at the top of the sheet bundle is provided at the upper part of the front end of the sheet storage unit 8. A storage unit temperature / humidity detection sensor 53 that detects the storage unit temperature / humidity above the sheet bundle is provided on the upper side of the side fence 13 on one side (in this example, on the right side in the sheet feeding direction).

  Although specific control will be described later, the first heating elements 51a and 51b are heated according to the detection result of the sheet temperature / humidity detection sensor 54, and the second heating element 52 is the storage section temperature / humidity detection sensor 53. By heating according to the detection result, the humidity above the top of the sheet bundle and the sheet bundle of the sheet storage unit 8 can be kept uniform at a certain level or lower.

  As a result, the adhesive force does not increase even with coated paper that generates a high adhesive force particularly in a high humidity environment, so that the sheet separating function by air assist can be enhanced. In addition, as shown in FIG. 12, the sheet near the air outlet 21 is curled by heating by the first heating elements 51a and 51b, and air easily enters between the sheets. Can be increased. The second heating element 52 includes not only the humidity of the sheet storage unit 8 mainly above the sheet bundle, but also a sheet feeding unit 9 including a sheet feeding roller 11, a separation roller 12a, a return roller 12b, and a guide plate. It is possible to dehumidify and stabilize the paper feed performance, and for example, water droplets due to high humidity on the roller surface and the guide plate are eliminated, so that the water droplets can be prevented from adhering to the sheet.

  The first heating elements 51a and 51b and the second heating element 52 are controlled so that the humidity detected by the sheet temperature / humidity detection sensor 54 and the storage section temperature / humidity detection sensor 53 is less than a set value, respectively. . For example, as shown in the graph of FIG. 14, it has been experimentally confirmed that the frequency of double feeding of coated paper can be greatly reduced by setting the humidity at the uppermost surface of the sheet bundle in the sheet storage unit 8 to 45% or less. By setting the set value to 45%, the sheet separation function by air assist can be further enhanced.

An example of specific control of the first heating elements 51a and 51b and the second heating element 52 is shown below.
When the sheet temperature / humidity detection sensor 54 detects 60% (or more), the first heating elements 51a and 51b are heated, and heating is stopped when 45% is detected. Further, when the storage portion temperature / humidity detection sensor 53 detects 60% (or more), the second heating element 52 is heated, and when 45% is detected, the heating is stopped. When both sensors are detected at 45% or less, it is not necessary to heat both heating means. Thereafter, the monitoring by both sensors is continued and the operation is continued.

  The sheet feeding operation by the sheet feeding unit 9 is performed when the value is equal to or less than the set value according to the detection results by the storage unit temperature and humidity detection sensor 53 and the sheet temperature and humidity detection sensor 54. Thereby, stable paper feeding performance can be maintained.

  The storage portion temperature / humidity detection sensor 53 is preferably located near the upper portion of the sheet bundle, but may be provided inside the sheet storage portion 8. The sheet part temperature / humidity detection sensor 54 preferably detects the uppermost part of the sheet bundle in a non-contact manner. However, the sheet part temperature / humidity detection sensor 54 may be in contact with the sheet part as long as it does not interfere with sheet conveyance and does not damage the sheet.

  The sheet feeding device 5 of the first to third embodiments described above feeds a sheet from the sheet storage unit 8 to the image forming apparatus main body 2 (FIG. 1). The image forming apparatus 1 is a digital copy. Machines, printers, fax machines and offset printing machines. In this description, the paper feeding device 5 is separated from the image forming apparatus main body 2, but may be provided in a paper feeding unit in the image forming apparatus main body 2. Further, the heating elements 51a, 51b, 52 and 55 may be arranged on the sheet width regulating surface side of the side fence 13 as long as they do not hinder sheet conveyance. You may arrange in.

  As mentioned above, although this invention was demonstrated by the example of illustration, this invention is not limited to this. For example, the shape and size (area) of the heating element provided around the air outlet can be set as appropriate. Moreover, the heat generation method is also arbitrary. The shape and size (area) of the air jet can also be set as appropriate. Further, the separation method of the paper feeding means is not limited to the FRR method, and any separation method can be adopted.

  Further, the image forming method of the image forming apparatus is arbitrary, and the image forming apparatus of any image forming method can be provided with the paper feeding device of the present invention without being limited to the electrophotographic method. Of course, the image forming apparatus is not limited to a printer, and may be a copier, a facsimile machine, or a multifunction machine having a plurality of functions.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image forming apparatus main body 5 Paper feeding apparatus (sheet feeding apparatus)
6 Bottom plate 8 Sheet storage (paper feed tray)
9 Paper feed unit (paper feed means)
DESCRIPTION OF SYMBOLS 11 Feed roller 12a Separation roller 12b Return roller 13 Side fence 14 End fence 20 Blower fan 21 Air outlet 51a, 51b 1st heating element 52 2nd heating element 53 Storage part temperature / humidity detection sensor 54 Sheet part temperature / humidity detection Sensor 55 Heating element (first heating element)
P Passing path (sheet transport surface)

Japanese Patent No. 3791581 JP 2006-27796 A Japanese Patent No. 3630636

Claims (15)

A sheet storage unit that stores the sheet bundle, a sheet feeding unit that feeds the sheet from the sheet bundle, a blowing unit that blows air to the sheet, and a blower port that sends out the wind sent from the blowing unit A sheet feeding apparatus comprising:
The blower opening is provided to face the upper end of the sheet bundle,
A sheet feeding apparatus having a first heating means for heating a sheet, which is substantially the same height as the sheet conveying surface with respect to the air blowing port and laterally to the air blowing port.   The sheet feeding apparatus according to claim 1, further comprising a second heating unit that heats the upper part of the sheet above the air blowing port. A sheet storage unit that stores the sheet bundle, a sheet feeding unit that feeds the sheet from the sheet bundle, a blowing unit that blows air to the sheet, and a blower port that sends out the wind sent from the blowing unit A sheet feeding apparatus comprising:
The blower opening is provided to face the upper end of the sheet bundle,
While having a first heating means for heating the sheet to the blower opening at substantially the same height as the sheet conveyance surface, on the lateral side of the blower opening,
A sheet feeding apparatus comprising a second heating means for heating the upper part of the sheet above the blower opening. It has a guide fence that guides the side edge of the sheet bundle,
The air blower and the first heating means, or the air blower and the first and second heating means are provided in the guide fence, according to any one of claims 1 to 3. The sheet feeding apparatus according to the description.   5. The sheet feeding apparatus according to claim 1, wherein the first heating unit is operated before the air is blown by the blowing unit.   The second heating unit is provided at a position where the position of the front end portion in the sheet conveying direction of the second heating unit is substantially equal to the position of the front end portion in the sheet conveying direction of the first heating unit. The sheet feeding apparatus according to any one of the above.   The sheet feeding apparatus according to claim 1, wherein the first heating unit is arranged so as to border the periphery of the air blowing port.   The sheet feeding apparatus according to claim 7, wherein the first heating unit is provided to heat the sheet storage unit and the upper end of the sheet bundle.   The sheet feeding apparatus according to claim 1, further comprising a control unit that controls a heat generation amount of each heating unit. A storage unit temperature / humidity detection unit for detecting temperature and humidity in the sheet storage unit, and a sheet temperature / humidity detection unit for detecting the temperature and humidity of the uppermost surface of the sheet bundle stored in the sheet storage unit,
Controlling the second heating means according to the detection result of the storage section temperature and humidity detection means,
The sheet feeding apparatus according to claim 9, wherein the first heating unit is controlled according to a detection result of the sheet temperature / humidity detection unit.   The control means controls the first heating means and the second heating means so that the humidity detected by the storage portion temperature / humidity detection means and the sheet temperature / humidity detection means is a predetermined value or less. The sheet feeding apparatus according to claim 10, wherein the sheet feeding apparatus is characterized.   The sheet feeding apparatus according to claim 11, wherein the predetermined value is 45%.   11. The sheet feeding apparatus according to claim 10, wherein operation of the sheet feeding unit is controlled in accordance with detection results of the storage unit temperature and humidity detection unit and the sheet temperature and humidity detection unit.   The sheet feeding apparatus according to any one of claims 1 to 13, further comprising a sheet upper limit position optimization mechanism that maintains an upper end position of the sheet bundle at a predetermined position.   An image forming apparatus comprising the sheet feeding device according to claim 1.

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