JP2007297149A - Paper feeding device for image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To positively prevent double feeding of sheets of paper regardless of fluctuation of paper quality, environment or the like and to exhibit paper feeding action with high reliability. <P>SOLUTION: In the paper feeding device, the sheets of paper are previously easily separated by blowing air from an air blowing fan 25 to the sheets of paper stored in a paper feed tray 31 and double feeding is prevented. It is detected that double feeding occurs utilizing a paper sensor 44 at a downstream side of a pair of separation rollers 42, it is determined that possibility of occurrence of double feeding is enhanced when generation of a sign of the double feeding is counted at a predetermined number, and an air amount of blown air is increased. A temperature of air is heated instead of an air amount, air may be blown to the paper at a suitable temperature, and both air amount and temperature may be suitably adjusted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet feeding device of an image forming apparatus that separates and takes out sheets one by one from a sheet feeding tray containing a large number of sheets, and sequentially feeds them to a predetermined conveyance path. The present invention relates to a technique for preventing so-called double feeding in which sheets of paper are overlapped and fed.

  There are various forms of paper as a recording medium applied to an image forming apparatus such as a printer or a copying machine, but cut paper cut into a predetermined size is particularly used. In an image forming apparatus using cut sheets, generally, a process for forming an image is performed by storing a sheet bundle in which a large number of sheets are stacked in a sheet feeding tray and setting the sheet bundle in the apparatus. A paper feeding method is employed in which the paper is sent to a provided conveyance path. Usually, the high quality paper supplied as cut paper has a relatively low surface smoothness and therefore has low adhesion between the papers, and therefore, the above multifeed is unlikely to occur.

  However, with the diversification of recording media, there is an increasing number of cases where an image is formed on a recording sheet having a relatively high surface smoothness such as an OHP sheet or a tracing paper. Even if a separation mechanism for separating the sheets one by one was provided, double feeding was likely to occur. In recent years, with the widespread use of full-color image forming apparatuses, high-gloss art paper or coated paper whose surface has been coated has been used in many cases. Such recording media have surface smoothness. Because it is extremely high and has high adhesion, many double feeds are invited. Therefore, in order to prevent double feeding of paper, a technique has been proposed in which air is blown to the side surface of a paper bundle in the tray so that the paper is easily separated (see Patent Documents 1 and 2).

JP 2005-96992 A JP 2004-331258 A

  The technique described in Patent Document 1 is designed not only to blow air on a sheet but also to change the air volume (wind speed) to be blown onto the sheet in accordance with the paper quality. By the way, it has been found that the use environment such as humidity has a great influence in addition to paper quality as a factor causing double feeding. Therefore, as in the technique of Patent Document 1, even if an air volume corresponding to the paper quality is simply blown, the paper is not necessarily separated. In other words, when one type of paper quality paper is used continuously, the air volume is constant. Therefore, when environmental changes such as humidity occur, double feeding may occur, and it can be said that reliability is lacking.

  The technique described in Patent Document 2 adjusts the air volume when the occurrence of double feed reaches a certain number of times, and an appropriate air volume according to the ease of occurrence of double feed that varies depending on the paper quality. It can be sprayed on the paper. That is, the air volume is adjusted to prevent double feed when it is determined that double feed is likely to occur after a certain number of double feeds. However, even if the set number of times is at least that number of times, multiple feeds will occur, so it is not a reliable double feed prevention measure and is a technology that remains frustrated.

  Therefore, the present invention provides a paper feeding device for an image forming apparatus that can reliably prevent double feeding of papers regardless of changes in paper quality, environment, etc., and can exhibit a highly reliable paper feeding operation. The purpose is to do.

  The present invention provides a paper feed tray for storing a plurality of paper sheets in a stacked state, a paper feed means for sending the paper contained in the paper feed tray to a predetermined supply destination, and a paper contained in the paper feed tray. By the air blowing means for blowing air, the air condition adjusting means for adjusting the air blowing condition of the air blowing means, the separating means for separating the sheets sent from the paper feeding means one by one, and the separating means, Double feed sign detection means for detecting a sheet to be fed first and a sheet that is shifted in the paper feed direction but overlapped with the preceding sheet by the paper feed means, and this double feed sign detection A counting means for counting the number of times of double feed sign detection of the means, and a control means for controlling the air condition adjusting means based on the number of double feed signs counted by the counting means. It is characterized.

  According to the present invention, in a paper feeding device that blows air to paper contained in a paper feed tray to prevent double feeding, the double feeding sign detection means detects that double feeding is about to occur and The point is a control mode in which it is determined that the possibility of double feeding has increased when the occurrence of the “feeding operation to predict” has been counted a predetermined number of times, and the blowing condition of air to be blown is changed as appropriate. Therefore, regardless of the paper quality and size of the paper, even if the usage environment such as humidity is different, the occurrence of a sign of double feed is used as the judgment material, so double feed is surely prevented before double feed occurs. be able to.

  In the present invention, in addition to the number of occurrences of the double feed precursor, the paper quality or size of the paper, which is a factor causing the double feed, is input to the control means, and the air blowing conditions are controlled based on these information. Thus, more accurate control is performed according to the paper quality and size. As described above, it is easy to double feed when the smoothness of the paper is high. Regarding the size, it can be said that the larger the size, the greater the friction in the overlapping state, that is, the larger the size, the easier the double feeding occurs. Therefore, control including information such as paper quality and size in advance is advantageous for high-precision control.

  Now, the air blowing conditions (air conditions) referred to in the present invention include the air volume and the temperature. That is, when the double feed sign is counted a predetermined number of times, the air volume blown from the air blowing means to the paper is changed, or the temperature of the air is changed. Further, the present invention includes the case where both the air volume and temperature are changed. The air condition adjusting means when the air condition is the air volume is an air volume adjusting means. The air condition adjusting means when the air condition is temperature is air temperature adjusting means.

  The larger the air volume, the lower the degree of adhesion between the sheets and the more difficult it is to cause double feeding. Therefore, when the air blowing condition is the air volume, a control mode is adopted in which the air volume adjusting means is controlled so that the air volume of the air blowing means increases when the number of double feed signs counted by the counting means reaches a predetermined number. .

  In addition, when the humidity is high, the weight of the paper itself increases, so that the degree of adhesion of the paper in the overlapped state increases and multi-feeding easily occurs. Therefore, the higher the temperature of the air, the lower the humidity and the more difficult the double feed occurs. Therefore, when the air blowing condition is temperature, a control form for controlling the air temperature adjusting means so that the temperature of the air blown from the air blowing means rises when the number of multiple feed signs counted by the counting means reaches a predetermined number Is taken.

  According to the present invention, it is possible to detect the occurrence of a double feed sign that is likely to cause double feed of paper, and appropriately control the air blowing conditions for blowing the paper in the paper feed tray based on the number of detections. Therefore, it is possible to reliably prevent double feeding of papers regardless of changes in paper quality, environment, etc., and to exhibit a highly reliable paper feeding operation.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 schematically shows the overall configuration of an image forming apparatus according to an embodiment. In this apparatus, a manual feed unit 20 is connected to a main body 10, and an external feed tray is connected to the manual feed unit 20. 31 is connected. A plurality of paper feed trays 12 that are classified according to the type of paper such as size and paper quality are arranged at the lower part of the main body 10 in the cabinet 11 so as to be freely inserted and removed from the outside of the cabinet 11. These sheet feed trays 12 store a bundle of sheets PP in which a large number of sheets of a predetermined size and quality are stacked. In the upper part of the cabinet 11, a print unit 13 for forming an image by electrophotography is provided.

  The printing unit 13 is configured such that a developing unit 15 and a fixing unit 16 are arranged on the print conveyance path 14 provided horizontally from the left side in FIG. Image data is supplied to the developing unit 15 from an external image output device (not shown) such as a personal computer or an image reading device via a communication line. In the developing unit 15, a toner image based on the image data is formed by being transferred to the surface of the paper conveyed on the print conveyance path 14. The sheet on which the toner image has been transferred is conveyed through the print conveying path 14 and is pressurized while being heated in the fixing unit 16, whereby the toner image is fixed on the surface of the sheet. The sheet on which the image is formed and fixed on the surface through the fixing unit 16, that is, the printed sheet is discharged from the print conveyance path 14 to a discharge tray 17 outside the cabinet 11.

  In the cabinet 11, for each paper feed tray 12, a paper feed conveyance path 18 that merges from the paper feed tray 12 to the downstream side (left side in FIG. 1) of the print conveyance path 14 is provided. At the time of printing, one type of paper, that is, one paper feed tray 12 is selected, and the uppermost paper in the selected paper feed tray 12 is fed by a paper feed means (not shown) provided in the paper feed tray 12. The sheet is sent to the conveyance path 18 and then printed on the surface while being conveyed on the print conveyance path 14.

  The manual feed unit 20 includes a cabinet 21 having a height equivalent to that of the cabinet 11 of the main body unit 10. On the upper part of the cabinet 21, a manual feed tray 22 for manually supplying paper to the printing unit 13 is detachably set. A manual feed path 23 that joins the print feed path 14 of the main body 10 is provided in the cabinet 12. When printing on the paper in the manual feed tray 22 is selected, the paper set on the manual feed tray 22 is transported through the manual feed path 23 and merges with the print transport path 14 of the main body unit 10. 14 is conveyed by the printing unit 13 as described above while being conveyed 14.

  The paper feed tray 31 constitutes the paper feed device 30 of the present invention, and the paper feed tray 31 includes a cabinet 32 having a height lower than that of the cabinet 21 of the manual feed unit 20. In the cabinet 32, a sheet feed stand 33 is provided on which a bundle of sheets on which many sheets are stacked is placed from outside the cabinet 32. The sheet feed table 33 is provided with a regulating plate (not shown) for positioning so that the sheet bundle placed at a predetermined position does not collapse. The paper feed table 33 is always urged upward by a biasing member (not shown) such as a spring provided at the bottom of the cabinet 32. As a result, the upper surface of the sheet bundle, that is, the end on the conveyance direction side (main body unit 10 side) of the first sheet to be fed comes into contact with the sheet feeding mechanism (sheet feeding means) 40 and the first sheet is fed. The height of is kept constant.

  The paper feed mechanism 40 takes out the paper one by one from the paper feed tray 31 and sends it out to the print transport path 14 of the main body 10. As shown in FIG. 2, the extraction rolls 41 arranged in the order of the paper transport direction, A separation roll pair (separation means) 42 including a pair of rolls 42 a and 42 b, a conveyance roll pair 43 including a pair of rolls 43 a and 43 b, and a paper sensor 44 are provided. Each roll is rotatably supported by a frame 45 fixed to the paper feed tray 31.

  As shown in FIG. 5, the extraction roll 41 rotates forward in the paper transport direction (rightward in FIG. 5), and acts to feed out the top paper P in the paper feed tray 31 in the transport direction. The upper surface (the surface of the uppermost sheet P) of the sheet bundle PP in the sheet feed tray 31 is always in elastic contact with the lower surface of the extraction roll 41 by the urging member.

  Each of the rolls 42a and 42b of the separation roll pair 42 is a drive roll, and there is a minute gap between the two, and the rotation directions of these rolls 42a and 42b are set to be the same as shown in FIG. ing. That is, the upper roll 42a rotates forward in the paper transport direction, and the lower roll 42b rotates reversely with respect to the transport direction. When two sheets fed out by the extraction roll 41 are overlapped, the separation roll pair 42 normally conveys the upper sheet by the upper roll 42a, while conveying the lower sheet to the lower roll 42a. It restricts with the roll 42b and the passage between the rolls 42a and 42b is prevented. By such an action, the two overlapped sheets are separated, and only the upper sheet is sent to the transport roll pair 43.

  One of the transport roll pair 43 is a drive roll and the other is a driven roll, and these rolls 43a and 43b are in contact with each other with a certain pressure. The pair of transport rolls 43 sandwiches the paper in the nip where the rolls 43a and 43b contact, and transports the paper toward the manual feed tray 22 by friction. A paper feed transport path 46 is formed from the extraction roll 41, the separation roll pair 42, and the transport roll pair 43 to the inside of the manual feed unit 20, and this paper feed transport path 46 joins the print transport path 14. The paper stored in the paper feed tray 31 is conveyed by the paper feed mechanism 40 through the paper feed conveyance path 46, and then printed by the printing unit 13 as described above while being conveyed on the print conveyance path 14. .

  The sheet sensor 44 is of an optical type or the like, and is disposed in the sheet feeding / conveying path 46 immediately above the separation roll pair 42. The sheet sensor 44 detects whether or not there is a sheet in the sheet feeding / conveying path 46 immediately below, that is, whether or not the sheet is conveyed immediately after the pair of separation rolls 42.

  As shown in FIG. 3, a blower unit 50 is fixed to one side of the paper feed tray 31. The blower unit 50 has a cabinet 51, and a blower fan (air blowing means) 52 is accommodated in the cabinet 51. The blower fan 52 is supported by the cabinet 51 with a blowout port 52 a for blowing out air directed toward the paper feed tray 31. The cabinet 51 and the cabinet 32 of the paper feed tray 31 are respectively formed with air holes (not shown) for blowing the air from the blower fan 52 onto the sheet bundle. The air blown out from the blowout port 52a of the blower fan 52 passes through the blower holes and hits the end portion on the front side (left side in FIG. 2) in the sheet bundle conveyance direction. The blower fan 52 is operated by a motor 53 (see FIG. 4), and the air volume (wind speed) can be adjusted in a plurality of stages by changing the rotation speed of the motor 53. The blower fan 52 has a built-in heater 54 that can adjust the temperature of the blown-out air in a plurality of stages.

  The sheet feeding device 30 according to the present invention includes the sheet feeding tray 31, the sheet feeding mechanism 40, and the air blowing unit 50. Further, as shown in the block diagram of FIG. A control device (control means) 60 for controlling a certain air volume and temperature is provided. Further, the sheet feeding device 30 has a motor 55 that is a driving source of the blower fan 52. The motor 55 is driven / stopped by an air volume adjusting unit (air condition adjusting means, air volume adjusting means) 61 and the air volume is set in a plurality of stages. It has come to be adjusted. Further, the sheet feeding device 30 includes an air temperature adjusting unit 62 that adjusts the temperature of the air from the blower fan 52 by adjusting the heating temperature of the heater 54 in a plurality of stages. FIG. 4 shows a motor 47 that drives the rolls 42 a and 42 b of the separation roll pair 42.

  The control device 60 is composed of a CPU, and this control device 60 prevents double feeding that the sheets are not normally separated by the separation roll pair 42 and two or more sheets overlap and pass through the separation roll pair 42. As described above, the air volume adjusting unit 61 and the air temperature adjusting unit 62 are controlled. The control is performed on the basis of a conveyance situation that gives an indication of double feed. Hereinafter, the double feed indication in this embodiment is defined.

  First, FIGS. 5A to 5E show a conveyance mode in which two sheets P are fed out from the sheet feeding tray 31 by the extraction roll 41 but are judged to be normally fed. That is, (a) the two sheets P are fed out from the sheet feeding tray 31 by the extraction roll 41, and (b) the two sheets P reach the separation roll pair 42. Then, (c) the upper sheet P, that is, the sheet P to be preceded, is conveyed by the upper roll 42a that rotates forward, while the lower sheet P is prevented from being conveyed by the lower roll 42b that rotates in the reverse direction. At this time, the paper P is detected by the paper sensor 44. In (d) to (e), the upper sheet P is transferred from the separating roll pair 42 to the conveying roll pair 43 and is normally conveyed, while the lower sheet P is continuously conveyed by the reverse rotating roll 42b. Therefore, the paper sensor 44 does not detect the paper P, and it is determined that the paper feeding is completed.

  Next, FIGS. 6A to 6E show cases in which a sign of double feeding has occurred. First, FIGS. 6A to 6B are the same as FIG. 5, but (c) overlapped sheets. The adhesiveness of P is high, and the transport of the lower sheet P cannot be prevented even by the action of the reverse rotation roll 42b of the pair of separation rolls 42, and the two sheets are transported while being overlapped to the position of the sheet sensor 44. . Then, (d) the upper sheet P is conveyed by the forward rotating roll 42a, but the lower sheet P is finally blocked by the reverse rotating roll 42b, and (e) the upper one sheet P is conveyed. To go. However, at the time of (c), the lower sheet P is being conveyed and enters the detection range of the sheet sensor 44. For this reason, the paper P is detected by the paper sensor 44 even if double feeding is avoided as shown in FIG. That is, a double feed sign is defined when it is determined that the paper feed of the preceding paper P is completed while “paper present” is detected by the paper sensor 44. A paper feed completion sensor for detecting whether or not paper feeding is completed detects the trailing edge of the paper P, and is provided in the paper feeding mechanism 40 although not shown.

  As shown in FIG. 4, the control device 60 includes a storage unit 63 composed of a ROM / RAM, a paper separation control unit 64, a paper detection unit (double feed sign detection unit) 65, and a count unit (counting unit) 66. Information is exchanged with the sheet information detection unit 67 and a control signal is output to the air volume adjustment unit 61 and the air temperature adjustment unit 62 based on the information. The storage unit 63 stores a permissible limit number (hereinafter referred to as a multifeed sign) of an air volume and the number of occurrences of a multifeed sign according to a paper size (A6, B6, A5, etc.) and a paper type (plain paper, coated paper, OHP sheet, etc.) Table T) (referred to as the allowable number of occurrences), and the minimum air volume 1 to the maximum air volume N of the air blown from the blower fan 52 are stored. Further, the storage unit 63 stores the normal number of sheets fed to which the counted number of double feed signs is cleared (set to 0). The sheet separation control unit 64 receives the driving status of the motor 47 of the separation roll pair 42.

  The paper detection unit 65 receives a detection signal from the paper sensor 44 and converts the detection level into a value that can be determined. The count unit 66 detects the number of occurrences of double feed signs determined based on the completion of feeding of the preceding paper while the paper sensor 44 input to the paper detection unit 65 detects “paper present”, and normal feeding. Count the number of sheets. The paper information detection unit 67 is supplied with paper size and paper quality information input through an operation panel (not shown) provided in the main body unit 10.

The above is the sheet feeding device 30 of the present embodiment. Next, the operation of the sheet feeding device 30 to prevent double feeding by the control device 60 will be described with reference to FIG.
First, when the power is turned on, the initial state is set, and then the user selects the type (paper quality) and size of the paper stored in the paper feed tray 31 on the operation panel. The paper information is supplied to the paper information detection unit 67, and the control device 60 obtains the paper information (step S101). Next, with reference to the table T stored in the storage unit 63, the air volume corresponding to the selected paper size and paper quality and the allowable number of occurrences of double feed precursors are determined (step S102). Further, in the counting unit 66, both the number of sheets normally fed and the count number of the occurrence of the double feed sign are set to 0 (step S103).

  The control device 60 waits for a paper feed command (step S104). When the paper feed command is received, the control device 60 sends a signal to the air volume adjusting unit 61 so as to blow air from the blower fan 52 with the air volume determined in step S102. From the blower fan 52, air is blown to the upper part of the front end of the sheet bundle with the air volume (step S105). As a result, air enters between the sheets of the portion and the sheets are separated, and sheet feeding / printing is continued as follows.

  First, the uppermost sheet of the sheet bundle is pulled out by the extraction roll 41 of the sheet feeding mechanism 40, and the sheet is conveyed in the order of the separation roll pair 42 and the conveyance roll pair 43, passes through the manual feed unit 20, and passes through the print conveyance path. 14 is printed on the paper by the printing unit 13 and then discharged to the paper discharge tray 17. In the course of such a single paper feeding / printing operation, it is determined whether or not the paper feeding is completed based on the detection status of the paper feeding completion sensor (step S106), and if it is determined that the paper feeding is completed. Then, a stop signal is sent to the air volume adjusting unit 61 to finish the air blowing (step S107).

  Further, it is determined whether or not a “paper present” signal from the paper sensor 44 is supplied to the paper detection unit 65, that is, whether or not a double feed sign has been generated in a state in which the completion of paper feed is detected (step) S108) If it is determined that a double feed sign has occurred, the counting unit 66 counts the number of double feed signs that have occurred (step S109). If it is determined in step S109 that there is no double feed sign, the number of normal sheets is counted (step S110). Next, it is determined whether or not the count number of the normal number of sheets fed has reached the number at which the count number of the double feed sign is cleared (step S111), and if not, the process returns to step S104. When the number of normal paper feeds reaches the number at which the count number of double feed signs is cleared, the normal paper feed number and the number of occurrences of double feed signs are set to 0 by the counting unit 66 (step S112).

  When the number of occurrences of double feed signs is counted in step S109, it is next determined whether or not the count has reached the allowable number determined in step S102 (step S113). It is assumed that the double feed does not actually occur at the stage of the sending sign and the air volume is appropriate, and the process returns to step S104. Then, when the count number of occurrences of double feed signs reaches an allowable number in step S113, it is determined whether or not the amount of air blown from the blower fan 52 is maximum (N) (step S114). In step S103, the sheet feeding / printing is repeated. If it is determined in step S114 that the air volume of the blower fan 52 is not the maximum, the air volume is increased by one level (step S115), and then the process returns to step S103 and the number of sheets normally fed in the counting unit 66 is overlapped. Both counts of the number of occurrences of transmission signs are set to 0, and these numbers are counted again.

  The above is the operation of the sheet feeding device 30 of the present embodiment. If the occurrence of double feed signs does not decrease even if the air volume of the blower fan 52 increases, the number of occurrences of double feed signs is counted one after another, The air volume of the blower fan 52 increases stepwise. On the other hand, if the number of occurrences of the double feed sign does not increase, the air volume of the blower fan 52 is appropriate, and the air volume is controlled to be constant as it is. In this embodiment, when the paper feed tray 31 is opened and a new sheet is loaded, the paper tray 31 is reset to the initial state by the opening / closing operation of the paper feed tray 31, and the above operation is started again. Yes.

  According to the paper feeding device 30 of this embodiment, air is blown from the blower fan 52 to the paper stored in the paper feeding tray 31 to separate the paper in advance, or the paper is fed from a state in which the paper is easily separated. Is something that starts. Then, the number of occurrences of double feed signs is counted in the process in which the paper is transported through the paper feed mechanism 40, and as the number of times increases, the paper is coming into close contact due to insufficient air volume from the blower fan 52. When it is determined that the possibility of actual double feeding has increased, and the occurrence of a double feed precursor reaches the allowable number of times, the air volume from the blower fan 52 is increased by one step. In this way, paper is fed while detecting the occurrence of double feed signs one by one, and when the number of occurrences reaches the limit, the air volume is increased, regardless of the paper quality and size, and the use of humidity etc. Even if the environment is different, it is possible to reliably prevent double feeding before double feeding occurs.

  In the above embodiment, the temperature of the air blown from the blower fan 52 can be heated by the heater 54 to blow the hot air onto the paper. When the air blown onto the paper is warm air, the paper in the paper feed tray 31 is dried and lightened, especially when the humidity is high, and can be easily separated. Further, the heating temperature by the heater 54 can be adjusted stepwise by the air temperature adjusting unit 62. Therefore, it is possible to prevent double feeding by adjusting the temperature of the air blown out from the blower fan 52 instead of adjusting the air volume while keeping the air volume constant. In that case, the air volume shown in FIG. 4 is replaced with temperature, and when the number of occurrences of double feed signs reaches an allowable value, the temperature is increased step by step.

  When the hot air is blown onto the paper in this way, not only temperature adjustment but also a combined type that performs both air volume adjustment and temperature adjustment can be adopted. In that case, a large number of combinations of air volume and temperature are set, and the temperature and air volume are set according to the sheet feeding condition after knowing in advance which combination is effective for preventing double feeding.

1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. It is sectional drawing of the paper feeder which concerns on one Embodiment. FIG. 3 is a top view of the paper feeding device in FIG. 2. 2 is a block diagram illustrating a configuration of a paper feeding device. FIG. FIG. 10 is a side view illustrating an example of a normal sheet feeding state by a sheet feeding device. FIG. 10 is a side view illustrating an example of a double feeding state of sheets by a sheet feeding device. 6 is a flowchart of an operation example of the sheet feeding device.

Explanation of symbols

30: Paper feeding device, 31: Paper feeding tray, 40 ... Paper feeding mechanism (paper feeding means)
42 ... Separation roll pair (separation means), 52 ... Blower fan (air blowing means),
60 ... Control device (control means),
61 ... Air volume adjusting unit (air condition adjusting means, air volume adjusting means)
62 ... Air temperature control section (air temperature control means)
65... Paper detection section (double feed sign detection means), 66... Count section (counting means)
PP ... paper bundle, P ... paper

Claims (7)

A paper feed tray for storing a plurality of sheets stacked,
A paper feed means for feeding the paper stored in the paper feed tray to a predetermined supply destination;
Air blowing means for blowing air onto the paper stored in the paper feed tray;
Air condition adjusting means for adjusting the air blowing conditions of the air blowing means;
Separating means for separating the sheets fed from the sheet feeding means one by one;
A multi-feed sign detection unit that detects a sheet to be fed first by the separating unit and a sheet that is shifted in the feeding direction by the sheet feeding unit and overlapped with the preceding sheet; ,
Counting means for counting the number of times of double feed sign detection by this double feed sign detection means;
A sheet feeding device for an image forming apparatus, comprising: a control unit that controls the air condition adjusting unit on the basis of the number of double feed signs counted by the counting unit.   The paper quality of the paper to be fed is input to the control means, and the control means controls the air condition adjusting means based on the paper quality and the number of double feed signs counted by the counting means. The sheet feeding device of the image forming apparatus according to claim 1.   The control means is supplied with the size of the paper to be fed, and the control means controls the air condition adjusting means based on the size and the number of double feed signs counted by the counting means. The sheet feeding device of the image forming apparatus according to claim 1. The air condition is an air volume, and the air condition adjusting means is an air volume adjusting means;
4. The control unit according to claim 1, wherein the control unit controls the air volume adjusting unit based on the number of double feed signs counted by the counting unit to adjust the air volume of air blown from the air blowing unit. A sheet feeding device of the image forming apparatus according to the above.   The said control means controls the said air volume adjustment means so that the air volume of the said air blowing means increases, when the frequency | count of the double feed precursor counted by the said count means reaches predetermined number of times. A sheet feeding device of the image forming apparatus according to claim 4. The air condition is a temperature, and the air condition adjusting means is an air temperature adjusting means;
The said control means controls the temperature of the air sprayed from an air spraying means by controlling an air temperature adjustment means based on the number of times of multiple feeds counted by the counting means. A sheet feeding device of the image forming apparatus according to claim 1.   The control means controls the air temperature adjusting means so that the temperature of the air blown from the air blowing means is increased when the number of double feed signs counted by the counting means reaches a predetermined number. The sheet feeding device of the image forming apparatus according to claim 6.

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