JP2010254462A - Paper feeder, paper feed unit, image forming device, and image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To feed paper at high speeds without causing a defective conveyance such as the double feeding and no suction of paper. <P>SOLUTION: Levitating air and separating air with predetermined air volumes are blown against a sheet P. A camera 70 acquires an image between an uppermost sheet against which the levitating air and the separating air are blown and the next sheet. A control means calculates the distances between the uppermost sheet and the next sheet from the image acquired by the camera 70. Based on the calculated result of the distance between the uppermost sheet and the next sheet, the sign of double feeding or the sign of no suction of the sheet P can be recognized. Therefore, before the double feeding or no suction of the sheet P occurs, the volumes of the levitating air and the separating air can be regulated and optimized. Since the air is blown against the sheet P with the optimized air volume, the sheet P can be levitated a predetermined distance only to thereby reliably separate sheet one by one. As a result, since the double feeding and the defective no suction of the sheet P can be reliably prevented from occurring, the sheet P can be fed at high speeds. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a paper feeding device, a paper feeding unit, an image forming apparatus, and an image which blows air to the edge of the loaded paper to float the paper and sucks and feeds the paper to a suction surface constituted by a conveyance belt or the like. It relates to a forming system.

  2. Description of the Related Art In recent years, an air feeding device that is a paper feeding device capable of feeding a large amount of paper is used in an image forming apparatus such as a copying machine or a printer. The air feeding device blows air onto the loaded paper, floats the paper, sucks the paper with a suction surface such as a perforated belt with an air inlet through which air is sucked, and rotates the belt. Transports paper. In such a paper feeding device, if the amount of air blown onto the paper is not appropriate, the paper may not be attracted to the suction surface or the paper may be double fed.

  The optimum airflow amount of the air blown onto the paper varies depending on the manufacturer of the paper and the condition of the paper at that time (water content, cutting state, etc.), even for the same paper size, the same basis weight, and the same paper type. Therefore, it is very difficult to set the optimum air volume by predicting the condition of the paper. Further, the paper feeding device is required to feed paper at high speed in order to feed a large amount of paper.

  Patent Document 1 discloses a paper feeding device that detects a sign of double feeding. According to Patent Document 1, the paper sensor detects that there are a plurality of sheets on the separation roller that separates the sheets, and counts the number of detections. The air volume of the floating air is controlled based on the counted number of detections.

JP 2007-297149 A (FIG. 6)

  By the way, the paper feeding device described in Patent Document 1 can adjust the air flow rate of the floating air based on the number of detections of the paper sensor. However, since it detects that a plurality of sheets overlap the separation roller, It is necessary to perform paper separation processing. Therefore, there is a problem that the time for feeding paper increases. Further, when paper is fed at a high speed, the paper is not separated by the separation roller, but the paper is double-fed and jamming such as paper jam may occur.

  The present invention solves such a problem, and can shorten a paper feeding time, and can feed paper at high speed without causing a paper conveyance failure such as double paper feeding, a paper feeding unit, An object is to provide an image forming apparatus and an image forming system.

  In order to solve the above-described problem, the paper feeding device according to claim 1 sucks the uppermost sheet loaded on the sheet loading table on which the sheet is loaded from the upper surface and sucks it on the suction surface, and on the suction surface. In the paper feeding device that transports the sucked paper to the paper transport path, an image between the blower mechanism that blows air to the paper with a predetermined air volume, and the uppermost paper blown by the blower mechanism and the next paper The image acquisition means for acquiring the image and the control means for calculating the distance between the uppermost sheet and the next sheet from the image acquired by the image acquisition means.

  In the paper feeding device according to the first aspect, the air blowing mechanism blows air at a predetermined air volume on the paper. The image acquisition means acquires an image between the uppermost sheet on which air is blown by the blower mechanism and the next sheet. The control unit calculates the distance between the uppermost sheet and the next sheet from the image acquired by the image acquisition unit.

  As a result, if the calculated distance is smaller than the predetermined distance, the sheets are close to each other, so that the double feeding of the sheets is likely to occur. If the calculated distance is larger than the predetermined distance, the sheets are separated from each other. Therefore, a non-adsorption failure in which the sheet does not adsorb to the adsorption surface is likely to occur. In other words, from the calculation result of the distance between the uppermost sheet and the next sheet, it is possible to recognize the sign of double feeding of sheets and the sign of non-adsorption failure where the sheets do not adhere to the suction surface.

  According to a second aspect of the present invention, in the paper feeding device according to the first aspect, the control means adjusts the air volume of the blower mechanism according to the calculated distance.

  In the paper feeding device according to the second aspect, the air volume of the air blowing mechanism can be optimized, and the air can be blown to the paper with the optimized air volume, so that the paper can be lifted and separated one by one.

  According to a third aspect of the present invention, in the paper feeding device according to the first aspect, the image acquiring unit acquires an image for a predetermined time, and the control unit continuously calculates a distance corresponding to the predetermined time, A time integration value obtained by integrating the distance with time is calculated from the calculation result, and the air volume of the blower mechanism is adjusted according to the calculated time integration value.

  In the sheet feeding device according to the third aspect, the air volume of the blower mechanism is adjusted according to the time integral value calculated by the control means, so that it is possible to reliably prevent the double feeding of sheets and the non-adsorption failure.

  According to a fourth aspect of the present invention, in the paper feeding device according to the first aspect, the image acquisition means acquires an image for a predetermined time, and the control means calculates a distance corresponding to the predetermined time, and from the calculation result. A time average value obtained by averaging distances by time is calculated, and the air volume of the blower mechanism is adjusted according to the calculated time average value.

  In the paper feeding device according to the fourth aspect, the air volume of the blower mechanism is adjusted according to the time average value calculated by the control means, so that it is possible to reliably prevent double feeding of paper and non-adsorption failure.

  According to a fifth aspect of the present invention, in the paper feeding device according to the first aspect, the air blowing mechanism includes a floating air mechanism that blows air to the paper stacked on the paper mounting table with a predetermined air volume, and a paper that is adsorbed to the suction surface. And a separation air mechanism that blows air at a predetermined air volume.

  In the sheet feeding device according to the fifth aspect, since the floating air mechanism blows air to the sheets stacked on the sheet placing table and the separation air mechanism blows air to the sheets adsorbed on the suction surface, Can be separated for each sheet.

  According to a sixth aspect of the present invention, in the paper feeding device according to any one of the second to fifth aspects, the control means is provided with a storage means for storing a predetermined time integral value or time average value, and the control means Compares the calculated time integral value or time average value with the predetermined time integral value or time average value stored in the storage means, and the calculated time integral value or time average value is the predetermined time integral value or time average. When the calculated value is smaller than the value, the air volume of the floating air mechanism is decreased, and when the calculated time integral value or time average value is larger than the predetermined time integral value or time average value, the air volume of the floating air mechanism is increased. It is what.

  In the paper feeding device according to claim 6, the control unit compares the time integral value or the time average value, and the air volume of the floating air mechanism is reduced or increased from the comparison result. Defects can be prevented.

  According to a seventh aspect of the present invention, in the paper feeder according to any one of the second to fifth aspects, the control means is provided with a storage means for storing a predetermined time integral value or time average value, and the control means The calculated time integral value or time average value is compared with a predetermined time integral value or time average value stored in the storage means, and the calculated time integral value or time average value is a predetermined time integral value or time average. The air volume of the separation air mechanism is increased when the value is smaller than the value, and the air volume of the separation air mechanism is decreased when the calculated time integral value or time average value is greater than a predetermined time integral value or time average value. It is what.

  In the paper feeding device according to claim 7, the control means compares the time integral value or the time average value, and reduces or increases the air volume of the separation air mechanism from the comparison result, so that the sheets are reliably separated for each sheet. This can prevent double feeding of paper.

  According to an eighth aspect of the present invention, there is provided a paper feeding unit that sucks, from the upper surface, one or more paper trays in which paper is stored and a topmost paper loaded on a paper tray on which the paper is loaded on the paper tray. In the paper feed unit that sucks and sucks the paper adsorbed on the suction surface to the paper transport path, a blower mechanism that blows air on the paper with a predetermined air volume, and the uppermost paper blown by the blower mechanism Image acquisition means for acquiring an image between the first paper and a control means for calculating a distance between the uppermost paper and the next paper from the image acquired by the image acquisition means. Is.

  In the paper feeding unit according to the eighth aspect, it is possible to recognize the sign of double feeding of paper and the sign of unadsorbed defect from the calculation result of the distance between the uppermost paper and the next paper.

  An image forming apparatus according to a ninth aspect of the present invention includes an image forming unit that forms an image on a sheet, and an uppermost sheet loaded on a sheet loading table on which the sheet is loaded, sucked from the upper surface, and sucked to the suction surface. In an image forming apparatus that conveys a sheet adsorbed on a surface to a sheet conveyance path, a blower mechanism that blows air on a sheet with a predetermined air volume, and a top sheet that is blown by the blower mechanism and the next sheet Image acquisition means for acquiring the first image, and control means for calculating the distance between the uppermost sheet and the next sheet from the image acquired by the image acquisition means.

  In the image forming apparatus according to the ninth aspect, it is possible to recognize the sign of double feeding of paper and the sign of non-adsorption failure from the calculation result of the distance between the uppermost paper and the next paper.

  An image forming system according to a tenth aspect of the present invention includes an image forming apparatus that forms an image on a sheet, and an uppermost sheet loaded on a sheet mounting table on which the sheet is loaded, sucked from the upper surface and sucked to the suction surface, An image forming system comprising: a sheet feeding device that conveys a sheet adsorbed on the surface to an image forming apparatus; and a control unit that controls the sheet forming apparatus to supply the sheet to the image forming apparatus and form an image on the image forming apparatus. The paper feeding device has a blower mechanism that blows air onto the paper with a predetermined air volume, and an image acquisition unit that obtains an image between the uppermost paper blown by the blower mechanism and the next paper. The control means calculates the distance between the uppermost sheet and the next sheet from the image acquired by the image acquisition means.

  In the image forming system according to the tenth aspect, from the calculation result of the distance between the uppermost sheet and the next sheet, it is possible to recognize the sign of the double feeding of the sheet and the sign of the non-adsorption failure.

  According to the paper feeding device of the present invention, it is possible to recognize signs of double feeding of paper and signs of non-adsorption failure, so that the air volume of the blower mechanism can be optimized before double feeding of paper or non-adsorption failure occurs. Since the air is blown onto the paper with the optimized air volume, it is possible to prevent double feeding of paper and non-adsorption failure. As a result, since the paper separation process is performed only by the air blowing mechanism, the paper feeding time can be shortened. Further, even if the paper is fed at a high speed, it is possible to prevent double feeding of the paper and to prevent the paper from being unsucked.

  According to the paper feeding unit according to the present invention, by providing the above-described paper feeding device, it is possible to optimize the air volume of the blower mechanism before the paper double feed or the non-adsorption failure, and the paper double feed or the non-adsorption failure. Can be prevented.

  According to the image forming apparatus of the present invention, by providing the above-described paper feeding device, it is possible to optimize the air volume of the air blowing mechanism before the double feeding of the paper and the non-adsorption failure, and the double feeding of the paper and the non-adsorption failure. Can be prevented. Further, since the paper separation process is performed only by the air blowing mechanism, the paper feeding time can be shortened and an image can be formed at high speed.

  According to the image forming system of the present invention, by providing the above-described paper feeding unit, the air volume of the blower mechanism can be optimized before double feeding or non-adsorption failure of paper, and double feeding or non-adsorption failure of paper. Can be prevented. Further, since the paper separation process is performed only by the air blowing mechanism, the paper feeding time can be shortened and an image can be formed at high speed.

1 is a side view illustrating a configuration example of a sheet feeding device 1 according to the present embodiment. 2 is a front view illustrating a configuration example of a sheet feeding device 1. FIG. 2 is a plan view illustrating a configuration example of a sheet feeding device 1. FIG. 3 is a block diagram illustrating a configuration example of a control system of the sheet feeding device 1. FIG. FIG. 6 is an enlarged side view illustrating an example of a sheet feeding operation when the sheet feeding apparatus is normal. 6 is a timing chart illustrating an example of a sheet feeding operation when the sheet feeding apparatus 1 is normal. 6 is an enlarged side view illustrating an example of a paper feeding operation when the paper feeding device 1 is in a double feed sign. FIG. 6 is a timing chart illustrating an example of a paper feeding operation when the paper feeding device 1 is in a double feed sign. FIG. 6 is an enlarged side view illustrating an example of a paper feeding operation when there is a sign of a non-adsorption failure of the paper feeding device. 6 is a timing chart illustrating an example of a paper feeding operation when there is a sign of a non-adsorption failure of the paper feeding device. 3 is a flowchart illustrating an operation example of the sheet feeding device 1. (A) is explanatory drawing which shows the range example of a normal value, (B) is explanatory drawing which shows the example of control of control means S1. 3 is an explanatory diagram illustrating a configuration example of a sheet feeding unit 100. FIG. 2 is an explanatory diagram illustrating a configuration example of an image forming apparatus 110. FIG. 1 is an explanatory diagram illustrating a configuration example of an image forming system 120. FIG.

  Hereinafter, a sheet feeding device, a sheet feeding unit, an image forming apparatus, and an image forming system will be described as an example of the present invention with reference to the drawings.

<Configuration Example of Paper Feed Device 1>
As shown in FIGS. 1 to 3, the sheet feeding device 1 displays an image between a floating air mechanism 45 and a separation air mechanism 5, which are an example of an air blowing mechanism that blows air onto a sheet, and between the uppermost sheet and the next sheet. It is comprised with the camera 70 which is an example of the image acquisition means to acquire. The paper feeding device 1 calculates the distance between the uppermost paper and the next paper from the image acquired by the camera 70. If the calculated distance is smaller than the predetermined distance, the sheets are close to each other, so that it is easy for double feeding of the paper P. If the calculated distance is larger than the predetermined distance, the sheets are separated. Therefore, a non-adsorption failure in which the paper P does not adsorb to the adsorption surface 30b is likely to occur. That is, from the calculation result of the distance between the uppermost sheet and the next sheet, it is possible to recognize the sign of double feeding of the sheet P and the sign of non-adsorption failure where the sheet P does not adhere to the suction surface.

  Details of the sheet feeding device 1 according to the present embodiment will be described below. The sheet feeding device 1 includes a sheet loading table 2 in a sheet storage unit 20 in which a space that can be stored in a form in which a predetermined number of sheets P are stacked is formed. The sheet placing table 2 is moved up and down along the stacking direction of the sheets P by a lifting mechanism (not shown). In the paper storage unit 20, a paper front end abutting surface 21 that holds the front end position of the paper P loaded on the paper placement table 2 is formed along the elevation direction of the paper placement table 2.

  The paper feeding device 1 includes an upper limit detection sensor 22 that detects the upper surface position Pu of the paper P stacked on the paper placement table 2. The upper limit detection sensor 22 includes, for example, a pair of optical sensors in which a detection position is formed at a predetermined position of the paper leading end abutting surface 21 along the stacking direction of the sheets P, and the upper limit detection sensor 22 of the sheets P stacked on the sheet mounting table 2. The upper surface position Pu is disposed at a position where it is detected that the upper surface position Pu is at the height H1 that can be sucked by the suction conveyance mechanism 3. For example, the output of the upper limit detection sensor 22 is OFF when there is no paper P at the suckable height H1, and the output is ON when the paper P is at the suckable height H1.

  In the sheet feeding device 1, when the stacking height of the sheet P on the sheet mounting table 2 is reduced by feeding out the sheet P stacked on the sheet mounting table 2 by the suction conveyance mechanism 3, the upper surface position Pu of the sheet P is changed. The sheet placing table 2 is raised to a position detected by the upper limit detection sensor 22, and the upper surface position Pu of the sheet P stacked on the sheet placing table 2 is controlled to be a height H 1 that can be sucked by the sucking and conveying mechanism 3. The

  The suction conveyance mechanism 3 includes a conveyance belt 30 at an upper portion of the paper storage unit 20. Further, the suction conveyance mechanism 3 includes a drive roller 31 around which the conveyance belt 30 is wound, a driven roller 32, and a driven roller group 33 having two driven rollers. The conveyor belt 30 is endless, and an intake port 30 a penetrating the conveyor belt 30 is formed in parallel in the width direction of the conveyor belt 30 and in the entire length direction orthogonal to the width direction of the conveyor belt 30.

  The drive roller 31 has an axis in a direction orthogonal to the conveyance direction of the paper P indicated by the arrow F, and is driven to rotate by a motor M1 described later with reference to FIG. The driven roller 32 and the driven roller group 33 have a shaft that is substantially parallel to the shaft of the driving roller 31, and have a rotatable configuration that is driven by the rotation of the conveying belt 30 when the driving roller 31 is driven to rotate.

  In the suction conveyance mechanism 3, a driven roller group 33 is disposed in front of the paper leading edge abutting surface 21 in the conveyance direction of the paper P indicated by the arrow F. In addition, a driving roller 31 is arranged on the upper part of the sheet placing table 2. Further, a driven roller 32 is disposed between the driven roller group 33 and the driving roller 31 at the upper part of the sheet placing table 2.

  In the suction conveyance mechanism 3, the conveyance belt 30 is stretched along the conveyance direction of the paper P between the driving roller 31 and the driven roller group 33. As a result, the suction conveyance mechanism 3 has a rear end side wound around the driving roller 31 of the conveyance belt 30 positioned above the sheet P stacked on the sheet loading table 2, and is positioned on the driven roller group 33 of the conveyance belt 30. The leading end side to be wound is positioned in front of the sheet leading end abutting surface 21. Further, the suction conveyance mechanism 3 has two conveyance belts 30. The two conveying belts 30 are provided in parallel to the left and right with respect to the conveying direction of the paper P. When the driving roller 31 is rotationally driven in the direction indicated by the arrow, each conveying belt 30 rotates, and the side of the conveying belt 30 facing the paper placing table 2 moves in the conveying direction of the paper P indicated by the arrow F.

  The lower end position on the circumferential surface of the drive roller 31 and the lower end position on the circumferential surface of the driven roller 32 are configured to have substantially the same height. On the other hand, in the driven roller group 33, the lower end position on the circumferential surface of the lower driven roller is configured to be higher than the lower end position of the driven roller 32 by a predetermined amount. Thus, the surface formed between the driving roller 31 and the driven roller 32 on the side of the transport belt 30 facing the paper mounting table 2 is substantially parallel to the surface of the paper P stacked on the paper mounting table 2. Become. On the other hand, the surface between the driven roller 32 and the driven roller group 33 is inclined upward along the conveyance direction of the paper P, and the conveyance belt 30 is at a portion wound around the driven roller 32. It becomes a bent surface.

  The suction transport mechanism 3 includes a suction chamber 34 into which air that sucks the paper P is sucked onto the transport belt 30. The suction chamber 34 has a space in which air is sucked by a fan (not shown) formed inside the conveyance belt 30, and a lower side facing the conveyance belt 30 located on the side facing the sheet placement table 2 is opened. Air is sucked in from the air inlet 30a of the conveyor belt 30 on the side facing 2.

  In the suction conveyance mechanism 3, when the air in the suction chamber 34 is sucked by a fan (not shown), the suction chamber 34 becomes negative pressure, so that the suction chamber 34 has a negative pressure from the suction port 30 a of the transport belt 30 located on the side facing the sheet placing table 2. Air is sucked in, and a flow of air that adsorbs the paper P to the transport belt 30 on the side facing the paper placement table 2 is generated. Accordingly, the suction surface 30b that sucks the paper P is configured by the transport belt 30 facing the paper placement table 2 in which air is sucked into the suction chamber 34 from the suction port 30a.

  The sheet feeding device 1 includes a sheet conveyance path 35 through which the sheet P fed out by the suction conveyance mechanism 3 is conveyed. The sheet conveyance path 35 includes a guide member that guides conveyance of the sheet P sucked and fed out by the adsorption conveyance mechanism 3, and includes a conveyance belt 30 on the side facing the sheet placement table 2 and a sheet leading end abutting surface 21. A sheet entrance 36 through which the sheet P enters is formed between the upper end.

  The sheet feeding device 1 includes a conveyance roller 37 and a driven roller 38 facing the conveyance roller 37 in the sheet conveyance path 35. The conveyance roller 37 is rotationally driven by a motor M2 described later with reference to FIG. 4, and conveys the paper P fed by the suction conveyance mechanism 3 while being sandwiched between the driven roller 38.

  The paper feed device 1 includes a paper feed detection sensor 39 in the paper transport path 35. The paper feed detection sensor 39 is composed of, for example, a pair of optical sensors in which a detection position is formed on the upstream side of the transport roller 37 and the driven roller 38, and is fed out by the suction transport mechanism 3 and transported by the transport roller 37. Is detected. For example, the output of the paper feed detection sensor 39 is turned on when the leading edge of the paper P fed out by the suction transport mechanism 3 reaches, and the output is turned off when the paper P is transported by the transport roller 37 and the rear end of the paper P comes out. .

  A side surface guide 4 is provided on the side surface of the paper placing table 2. The side guide 4 is movable in the width direction perpendicular to the conveyance direction of the paper P indicated by the arrow F, and supports the paper P so that the paper P does not move by contacting the side surface of the paper P stacked on the paper placement table 2. A rear guide 9 is provided on the rear surface of the paper placing table 2. The rear guide 9 is movable in the conveyance direction of the paper P indicated by the arrow F, and supports the paper P so that it does not move by contacting the rear surface of the paper P stacked on the paper mounting table 2.

  A floating air mechanism 45 is provided on the side guide 4. In the floating air mechanism 45, a floating air outlet (hereinafter referred to as an outlet 40) is formed on the side of the paper storage unit 20. In the floating air mechanism 45, the air sucked by the blower fan 41 is blown out as floating air from the outlet 40 through the duct 42. The floating air blown out from the air outlet 40 blows air onto the side surface of the paper P loaded on the paper mounting table 2.

  A separation air mechanism 5 is provided on the front surface of the sheet placing table 2. In the separation air mechanism 5, a separation air outlet (hereinafter referred to as an outlet 50) is formed in front of the paper storage unit 20. In the separation air mechanism 5, the air sucked by the blower fan 51 is blown out as separation air from the air outlet 50 toward the front end surface of the paper P. The separation air blown out from the air outlet 50 is oriented along the conveying belt 30 on the side facing the sheet placing table 2 and is blown onto the sheet P from the front of the sheet P adsorbed on the conveying belt 30.

  The sheet feeding device 1 includes a suction detection sensor 6 that detects the presence or absence of the paper P that is sucked to the transport belt 30 by the suction transport mechanism 3. The suction detection sensor 6 includes, for example, a pair of optical sensors, and detects the presence or absence of the detector 60 that is pushed up and displaced by the paper P sucked by the transport belt 30 by the suction transport mechanism 3. That is, when the sheet P is adsorbed to the conveyance belt 30 by the adsorption conveyance mechanism 3, a force for pushing up the detector 60 protruding from the adsorption surface 30b formed by the conveyance belt 30 is applied. When a force for pushing up the detector 60 is applied, the spring 61 is elastically deformed, and the detector 60 rotates about the shaft 62 and is displaced in the retracted direction with respect to the suction surface 30b.

  Further, when the sheet P attracted to the transport belt 30 is exhausted, the force for pushing up the detector 60 is not applied, and the detector 60 rotates about the shaft 62 by the elastic force of the spring 61 and protrudes from the suction surface 30b. Displace in the direction of As described above, the detector 60 is displaced by the rotation operation depending on whether or not the sheet P is attracted to the transport belt 30 by the suction transport mechanism 3. For example, the output of the suction detection sensor 6 is turned off when the paper P is not attracted to the transport belt 30, and the output is turned on when the paper P is attracted to the transport belt 30. Thereby, it can be determined from the output of the suction detection sensor 6 whether or not the paper P is sucked onto the transport belt 30.

  The sheet feeding device 1 includes a housing 7 that accommodates the suction conveyance mechanism 3, the side guide 4, the separation air mechanism 5, and the rear guide 9. A camera 70 is provided inside the housing 7. The camera 70 acquires an image between the uppermost sheet on which the floating air and the separation air are blown by the floating air mechanism 45 and the separation air mechanism 5 and the next sheet below the uppermost sheet. The camera 70 has a lens (not shown) and can be adjusted in focus. Since the camera 70 can be adjusted in focus, an image between the uppermost sheet and the next sheet can be acquired even if the sheet size is changed.

  In FIG. 3, the camera 70 is located between the side guide 4 and the separation air mechanism 5, but may be provided on the side guide 4 or in the vicinity of the upper limit detection sensor 22 of the separation air mechanism 5. It may be provided. A plurality of cameras 70 may be provided. Thereby, a plurality of images can be acquired at the same time, and the accuracy of adjustment of the blower fans 41 and 51 by the control means S1 to be described later with reference to FIG. 4 can be improved as compared to acquiring images with a single camera.

<Configuration Example of Control System of Paper Feed Device 1>
Next, a configuration example of the control system of the sheet feeding device 1 will be described. As shown in FIG. 4, the sheet feeding device 1 controls the sheet feeding control to feed out the sheets P stacked on the sheet placing table 2 described with reference to FIG. S1 is provided. The suction detection sensor 6, the paper feed detection sensor 39, the upper limit detection sensor 22, and the camera 70 are connected to the control means S1. The control means S1 is provided with a RAM 11, which is an example of a storage means. The RAM 11 stores in advance initial setting values related to the optimum air flow of the floating air and separation air corresponding to the paper size, basis weight, and paper type. The RAM 11 stores a time integration value or a time average value, which will be described later.

  The suction detection sensor 6 detects that the paper P is sucked on the transport belt 30 by the suction transport mechanism 3 shown in FIG. 1 and the like, and outputs the detection result to the control unit S1. The control unit S1 controls the motor M1 that drives the conveyance belt 30 depending on whether or not the sheet P is adsorbed to the conveyance belt 30 detected by the adsorption detection sensor 6.

  The paper feed detection sensor 39 detects that the leading and trailing edges of the paper P fed out by the suction conveyance mechanism 3 has reached a predetermined position, and outputs the detection result to the control means S1. The control unit S1 controls the motor M2 that drives the transport roller 37 according to the transport position of the paper P detected by the paper feed detection sensor 39.

  The upper limit detection sensor 22 detects that the upper surface position Pu of the paper P stacked on the paper placement table 2 is at a suction height H1 by the suction conveyance mechanism 3, and outputs the detection result to the control means S1. Based on the upper surface position Pu of the paper P detected by the upper limit detection sensor 22, the control unit S <b> 1 controls the motor M <b> 3 that raises and lowers the paper placement table 2, and the upper surface position Pu of the paper P stacked on the paper placement table 2. Is adjusted to the feedable height H1.

  The camera 70 acquires an image between the uppermost sheet on which air is blown by the floating air mechanism 45 and the separation air mechanism 5 and the next sheet below it, and outputs the acquired image to the control unit S1. To do. The control unit S1 calculates the distance between the uppermost sheet and the next sheet from the image acquired by the camera 70, and drives the blower fan 41 of the floating air mechanism 45 according to the calculated distance. The motor M5 that drives the blower fan 51 of the separation air mechanism 5 is controlled to adjust the amount of air blown onto the paper P.

<Example of sheet feeding operation of sheet feeding apparatus 1>
Next, an example of a paper feeding operation of the paper feeding device 1 will be described. Initial setting values regarding the optimum airflow of the floating air and separation air corresponding to the paper size, basis weight, and paper type are read from the RAM 11, and the floating air and separation air are applied to the paper with the airflow corresponding to the initial setting value. Assuming that

  As shown in FIG. 5, when the paper feeding device 1 normally transports the paper P to the paper transport path 35 without double feeding or non-adsorption failure, the uppermost paper attracted to the suction surface 30b and below it The distance between the next sheet becomes stable.

  In FIG. 6, when the horizontal axis is time, and the vertical axis is the distance between the uppermost sheet sucked on the suction surface 30 b and the next sheet below the uppermost sheet, the sheet feeding device 1 is fed in a normal state. It is a timing chart which shows the example of paper operation. From time t0 to time t2, the top sheet is the sheet P1, and the next sheet below the sheet P1 is the sheet P2. The camera 70 acquires an image between the paper P1 and the paper P2. The control means S1 calculates a distance D1 between the paper P1 and the paper P2 from the image acquired by the camera 70. For example, when the images on the sheets P1 and P2 are white images and the distance (gap) between the sheets P1 and P2 is a black image, the control unit S1 measures the number of pixels that become a black image. To calculate the distance D1. The sheet feeding device 1 sucks only the sheet P1 on the suction surface 30b and transports it to the sheet transport path 35 by the transport belt 30 while maintaining the distance D1 until time t1.

  From time t1 to time t2, the paper P1 is transported to the paper transport path 35 by the transport belt 30, and the distance between the paper P2 and the paper P1 decreases. The control means S1 calculates a time integral value or a time average value for the time t0 to the time t2. For example, in FIG. 6, the time integral value is obtained by integrating the distance between the paper P1 and the paper P2 by the time from the time t0 to the time t2, and the vertical axis, the horizontal axis, and the distance-time measurement line L1. It is the area surrounded by. The time average value is distance D1 / time t2 in FIG.

  The RAM 11 stores in advance a normal time integral value or a time average value when the paper feeder 1 is manufactured. The control means S1 compares the normal time integral value or time average value stored in the RAM 11 with the time integral value or time average value calculated by the control means S1. For example, when the control means S1 compares with the time integral value, the normal time integral value stored in the RAM 11 is surrounded by the vertical axis, the horizontal axis and the distance-time measurement line L1 calculated by the control means S1. The time integral value which is an area is compared. Further, when comparing with the time average value, the control means S1 compares the normal time average value stored in the RAM 11 with the time average value which is the distance D1 / time t2 calculated by the control means S1. The control means S1 recognizes from the comparison result that the calculated time integrated value or time average value is substantially the same value as the normal time integrated value or time average value. At time t2, the distance is 0, and the sheet P2 is attracted to the suction surface 30b and becomes the uppermost sheet, and the sheet P3 below the sheet P2 becomes the next sheet.

  From time t2 to time t3, the camera 70 acquires an image between the paper P2 sucked on the suction surface 30b and the next paper P3 below it. The control means S1 controls the motors M4 and M5 from the above comparison results to determine the air volume of the blower fans 41 and 51. In FIG. 6, since the normal time integral value and time average value stored in the RAM 11 and the time integral value and time average value calculated by the control means S1 are substantially the same value, the control means S1 is stored in the RAM 11. The motors M4 and M5 are controlled so that air is blown onto the paper P with an air volume corresponding to the initial set value. As a result, the uppermost sheet and the next sheet are always separated by the distance D1, and the sheet feeding device 1 can perform a normal sheet feeding operation.

  Next, an example of the operation of the paper feeding device 1 when the paper is showing signs of double feeding will be described. Initial setting values regarding the optimum airflow of the floating air and separation air corresponding to the paper size, basis weight, and paper type are read from the RAM 11, and the floating air and separation air are applied to the paper with the airflow corresponding to the initial setting value. Assuming that

  As shown in FIG. 7, when the paper feeder 1 transports the paper P to the paper transport path 35 when the paper is showing signs of double feeding, the uppermost paper sucked on the suction surface 30 b and below The distance to the next sheet in the is unstable. In FIG. 7, the paper P11 is transported to the paper transport path 35, the paper P12 is attracted to the suction surface 30b, and the paper P13 is approaching the paper P12. For example, the sheet P13 is close to the sheet P12 because the sheet density is low and the sheet is excessively levitated due to the wind pressure of the floating air, and the sheet P13 is also transported after the sheet P13. In the same manner as the above, there is a possibility that the levitation will occur excessively, and eventually the paper will be transported by being double fed to the paper transport path 35.

  In FIG. 8, the horizontal axis represents time, and the vertical axis represents the distance between the uppermost sheet adsorbed on the adsorption surface 30b and the next sheet below the sheet, and the double feeding of the sheet feeding device 1 is performed. 6 is a timing chart illustrating an example of a sheet feeding operation at the time of the sign of From time t0 to time t12, the uppermost sheet is the sheet P11, and the next sheet below the sheet P11 is the sheet P12. The camera 70 acquires an image between the paper P11 and the paper P12. The control unit S1 calculates a distance D1 between the paper P11 and the paper P12 from the image acquired by the camera 70. The sheet feeder 1 adsorbs only the sheet P1 to the adsorption surface 30b and conveys it to the sheet conveyance path 35 by the conveyance belt 30 while maintaining the distance D1 until time t11.

From time t11 to time t12, the paper P11 is transported to the paper transport path 35 by the transport belt 30, and the distance between the paper P12 and the paper P11 decreases. The reduction characteristic becomes unstable compared to the reduction characteristic described with reference to FIG. 6 because the paper is less likely to be separated by burrs caused by cutting the paper. The control means S1 calculates a time integral value obtained by integrating the distance between the paper P11 and the paper P22 by the time from the time t0 to the time t12, and calculates the calculated time integration value and a predetermined time stored in the RAM 11. Compare the integral value. The time integral value calculated by the control means S1 is an area surrounded by the vertical axis, the horizontal axis, and the measurement line L11.
In FIG. 8, the control unit S1 recognizes that there is an indication of double feeding because the time integration value calculated by the control unit S1 is smaller than the normal time integration value stored in the RAM 11. At time t12, the distance becomes 0, and the sheet P12 is attracted to the suction surface 30b and becomes the uppermost sheet, and the sheet P13 below the sheet P12 becomes the next sheet.

  From time t12 to time t13, the camera 70 acquires an image between the sheet P12 sucked on the suction surface 30b and the next sheet P13 below the sheet P12. The control unit S1 calculates a distance D2 between the paper P12 and the paper P13 from the image acquired by the camera 70. The distance D2 is a value smaller than the distance D1. That the distance D2 is smaller than the distance D1 indicates that the paper P12 and the paper P13 are close to each other. Generally, when sheets are close to each other, there is a high possibility that the sheets will be double-fed. The control means S1 calculates a time integral value obtained by integrating the distance between the paper P12 and the paper P13 by the time from the time t12 to the time t13, and the normal time stored in the RAM 11 is calculated. Compare the integral value. The time integral value calculated by the control means S1 is an area surrounded by the vertical axis, the horizontal axis, and the measurement line L12. The control means S1 calculates the time integral value and compares it with the normal time integral value stored in the RAM 11, but calculates the time average value which is the distance D2 / (time t13−time t12). You may compare with the normal time average value memorize | stored. Since the interval between the time integration values and the time average value calculated by the control means S1 are smaller than the normal time integration value and the time average value stored in the RAM 11, it is recognized that there is an indication of double feeding.

  Since the control means S1 recognizes that there is an indication of double feeding, the control means S1 controls the motor M4 to blow air onto the paper P with an air volume smaller than the air volume corresponding to the initial setting value stored in the RAM 11. Further, the control means S1 controls the motor M5 so that air is blown onto the paper P with an air volume larger than the air volume corresponding to the initial setting value stored in the RAM 11. As a result, the flying air and the separation air whose air volume is adjusted are blown onto the paper P, so that the uppermost paper and the next paper are separated by a distance D1, and the paper feeder 1 is shown in FIG. A normal paper feeding operation can be performed.

  Thereby, the paper feeding device 1 can recognize the signs of double feeding by the camera 70 and the control unit S1, and can adjust and optimize the air volume of the floating air and the air volume of the separation air before the paper P is double fed. . As a result, double feeding of the paper P can be prevented by blowing air onto the paper P with the optimized air volume.

  Next, an example of the operation of the paper feeding device 1 when the paper shows a sign that the suction surface 30b is not attracted properly will be described. Initial setting values regarding the optimum airflow of the floating air and separation air corresponding to the paper size, basis weight, and paper type are read from the RAM 11, and the floating air and separation air are applied to the paper with the airflow corresponding to the initial setting value. Assuming that

  As shown in FIG. 9, when the paper feeder 1 transports the paper P to the paper transport path 35 when the paper is showing no sign of being attracted to the suction surface 30b, for example, the water content of the paper becomes high and the paper Since the paper is heavy, the distance between the uppermost paper P22 sucked by the suction surface 30b and the next paper P23 below it is D3, which is larger than the distance D1. Similarly to the paper P23, the paper conveyed after the paper P23 continues to be in a state where the levitation is not sufficient, and there is a possibility that a non-adsorption failure that is not attracted to the suction surface 30b will occur.

  In FIG. 10, when the horizontal axis is time, and the vertical axis is the distance between the uppermost sheet adsorbed on the adsorption surface 30 b and the next sheet below the sheet, the non-adsorption of the sheet feeding device 1 is performed. 6 is a timing chart illustrating an example of a paper feeding operation when there is a sign of a defect. From time t0 to time t22, the topmost sheet is the sheet P21, and the next sheet below the sheet P21 is the sheet P22. The camera 70 acquires an image between the paper P21 and the paper P22. The control unit S1 calculates a distance D1 between the paper P21 and the paper P22 from the image acquired by the camera 70. The paper feeding device 1 sucks only the paper P21 on the suction surface 30b and transports it to the paper transport path 35 by the transport belt 30 while maintaining the distance D1 until time t21.

  From time t21 to time t22, the paper P21 is transported to the paper transport path 35 by the transport belt 30, and the distance between the paper P22 and the paper P21 decreases. The control means S1 calculates a time integral value obtained by integrating the distance between the paper P21 and the paper P22 by the time from the time t0 to the time t22, and the calculated time integration value and the normal time stored in the RAM 11 are calculated. Compare the integral value. The time integral value calculated by the control means S1 is an area surrounded by the vertical axis, the horizontal axis, and the distance-time measurement line L21. The control means S1 calculates a time average value which is a distance D3 / time t22 obtained by averaging the distances from time t0 to time t22, and compares it with the normal time average value stored in the RAM 11. Also good. From the comparison result, the control means S1 recognizes that the calculated time integral value or time average value is substantially the same value as the normal time integral value or time average value. At time t22, the distance becomes 0, and the paper P22 is sucked to the suction surface 30b and becomes the uppermost paper, and the paper P23 below the paper P22 becomes the next paper.

  From time t22 to time t23, the camera 70 acquires an image between the paper P22 sucked on the suction surface 30b and the next paper P23 below the paper P22. The control unit S1 calculates a distance D3 between the paper P22 and the paper P23 from the image acquired by the camera 70. The control means S1 calculates a time integrated value or a time average value from the calculated distance, and a predetermined time integrated value or time average value stored in the RAM 11 and the time integrated value or time average value calculated by the control means S1. And compare. For example, when the control means S1 compares with the time integral value, the normal time integral value stored in the RAM 11, the vertical axis, the horizontal axis calculated by the control means S1, and the time surrounded by the measurement line L22. Compare the integral value. When the control means S1 compares the time average values, the normal time average value stored in the RAM 11 and the time average value calculated by the control means S1 which is the distance D3 / (time t23−time t22) are used. Compare.

  In FIG. 10, since the time integrated value and the time average value calculated by the control means S1 in FIG. 10 are larger than the normal time integrated value and time average value stored in the RAM 11, there is no sign of unadsorbed failure. Recognize that there is. When recognizing that there is a sign of a non-adsorption failure, the control unit S1 controls the motor M4 so that air is blown onto the sheets after the sheet P22 with an air volume larger than the air volume corresponding to the initial setting value stored in the RAM 11. . In addition, the control unit S1 controls the motor M5 so that air is blown onto the sheets subsequent to the sheet P22 with an air volume smaller than the air volume corresponding to the initial setting value stored in the RAM 11. As a result, the flying air and the separation air whose air volume is adjusted are blown onto the paper P, so that the uppermost paper and the next paper are separated by a distance D1, and the paper feeder 1 is shown in FIG. A normal paper feeding operation can be performed.

  Thereby, the paper feeding device 1 recognizes the sign of the non-adsorption failure by the camera 70 and the control unit S1, and optimizes the air flow of the floating air and the air flow of the separation air before the paper becomes the non-adsorption failure. it can. As a result, it is possible to prevent the sheet P from becoming unsucked by blowing air onto the sheet P with the optimized air volume.

  Next, an operation example of the sheet feeding device 1 will be described using a flowchart. It is assumed that the time integration value and the time average value when performing a normal paper feeding operation are stored in the RAM 11 in advance. As shown in FIG. 11, in order to form a desired image on the paper P, the user operates an operation panel (not shown) in step ST1. Then, the control unit S1 drives the motors M1, M2, M3, M4, and M5 to operate the transport belt 30, the transport roller 37, the paper stacking table 2, and the blower fans 41 and 51, respectively. Start transporting.

  In step ST2, the control unit S1 causes the camera 70 to acquire an image between the uppermost sheet on which the flying air and the separation air are blown and the next sheet below the uppermost sheet, and that image It is made to output to control means S1.

  In step ST3, the control unit S1 calculates the distance between the uppermost sheet and the next sheet from the image output from the camera 70. The control means S1 calculates the distance for a predetermined time, and calculates a time integral value or a time average value from the calculation result.

  In step ST4, the control means S1 calculates the calculated time integrated value or time average value (hereinafter referred to as “calculated value”) and the time integrated value or time average value (hereinafter referred to as “normal value”) stored in advance in the RAM 11. Are compared to determine whether the calculated value is larger than the normal value range. If the calculated value is larger than the normal value range, the process proceeds to step ST5. If the calculated value is not larger than the normal value range, the process proceeds to step ST6.

  In step ST <b> 5, the control means S <b> 1 increases the rotational speed of the motor M <b> 4 from the initial setting value stored in the RAM 11 and increases the amount of floating air blown from the blower fan 41. In addition, the control unit S <b> 1 decreases the rotation amount of the motor M <b> 5 from the initial setting value stored in the RAM 11, and reduces the air volume of the separated air blown from the blower fan 51. Thereafter, the control unit S1 drives the motor M2 to operate the transport roller 37 to transport the paper P to the outside of the paper feeding device 1.

  In step ST6, the control means S1 determines whether or not the calculated value is smaller than the normal value range. If the calculated value is smaller than the normal value range, the process proceeds to step ST7. If the calculated value is not smaller than the normal value range, the calculated value is within the normal value range, so double feed and unadsorbed It is determined that the possibility of a failure is low, and the paper P is transported outside the paper feeding device 1 without adjusting the floating air and the separation air.

  In step ST <b> 7, the control unit S <b> 1 decreases the rotational speed of the motor M <b> 4 from the initial setting value stored in the RAM 11, and decreases the amount of floating air blown from the blower fan 41. Further, the control means S <b> 1 increases the rotational speed of the motor M <b> 5 from the initial setting value stored in the RAM 11 and increases the amount of separated air blown from the blower fan 51. Thereafter, the control unit S1 drives the motor M2 to operate the transport roller 37 to transport the paper P to the outside of the paper feeding device 1.

  That is, as shown in FIGS. 12A and 12B, if the calculated value is smaller than the minimum value Nmin of the normal value, the control means S1 reduces the air volume of the floating air and reduces the air volume of the separated air. increase. Further, if the calculated value is larger than the maximum normal value Nmax, the control means S1 increases the air volume of the floating air and decreases the air volume of the separated air. Further, if the calculated value is a value between the minimum value Nmin and the maximum value Nmax of the normal value, the control means S1 does not adjust the air volume of the floating air and the separated air.

  Thus, according to the paper feeding device according to the present embodiment, the floating air mechanism 45 blows air to the side surface of the paper P to float the paper P, and the separation air mechanism 5 blows air to the front surface of the paper P. The sheet P is separated one by one, and the camera 70 acquires an image between the uppermost sheet blown by the floating air mechanism 45 and the separation air mechanism 5 and the next sheet, and the control unit S1 The distance between the uppermost sheet and the next sheet is calculated from the image acquired by the camera 70.

  As a result, it is possible to recognize the sign of double feeding of the paper P and the sign of non-adsorption failure from the calculation result of the distance between the uppermost paper and the next paper. It is possible to optimize by adjusting the air volume of the floating air mechanism 45 and the separation air mechanism 5 before the double feeding of sheets or the non-adsorption failure. Since air is blown onto the paper P with this optimized air volume, the paper P can be lifted by a predetermined distance D1 and reliably separated one by one. As a result, the paper P is separated only by the floating air mechanism 45 and the separation air mechanism 5, so that the paper feeding time can be shortened. Even if the paper P is fed at a high speed, the double feeding of the paper P can be prevented, and the paper P can be prevented from becoming a non-adsorption defect. For example, even if there are burrs that occur when cutting A2 size paper into A3 size paper, the paper is separated with floating air and separation air with optimized airflow, so double feeding can be reliably prevented. . Further, even if the user changes the paper setting direction in the middle, multi-feed can be prevented.

  In the paper feeding apparatus 1 according to the present embodiment, the camera 70 has been described as an example of the image acquisition unit. However, an arrayed optical sensor or the like may be used. Further, although the camera 70 has been described to always acquire an image, the control means S1 acquires the image periodically, for example, every 3 seconds or every 100 sheets of paper transported, and the control means S1 integrates the time integral value or the time average value. May be calculated. Further, the camera 70 has acquired the image between the uppermost sheet and the next sheet, and the control unit S1 has been described to calculate the distance between the uppermost sheet and the next sheet. An image between the suction surface 30b and the next sheet is acquired, the control unit S1 calculates the distance between the suction surface 30b and the next sheet, and the floating air mechanism 45 and the separation air mechanism 5 are calculated from the calculation results. It may be optimized by adjusting the air volume.

<Configuration Example of Paper Feed Unit 100>
Next, the paper feeding unit 100 including the paper feeding device 1 according to the present embodiment will be described. As shown in FIG. 13, the paper feeding unit 100 includes a plurality of paper feeding devices 1. Furthermore, the sheet feeding unit 100 includes three sheet trays P220, P221, and P222 in the vertical direction as an example in the present embodiment. Further, on each of the paper trays P220, P221, and P222, a suction conveyance mechanism 3 having the conveyance belt 30 shown in FIG. Further, floating air is blown to the sides of the paper trays P220, P221, and P222 from the air outlet 40 on the side surface of the paper P stacked on the paper trays P220, P221, and P222, and the width direction of the paper P is maintained. A side guide 4 is provided.

  A separation air mechanism 5 is provided that blows separation air between the uppermost sheet and the next sheet from the air outlet 50 on the front end surface of the sheets P stacked on the sheet trays P220, P221, and P222.

  The paper trays P220, P221, and P222 are provided so that they can be pulled out in the front-rear direction of the drawing by opening a front door (not shown) provided on the front side of the drawing. The front surface of the paper tray can be configured as an exterior plate, and a handle or the like that can be put on the exterior plate can be provided, and the paper tray can be pulled out and pushed in using the handle or the like.

  The paper feeding direction of the paper P by the suction conveyance mechanism 3 is a direction (left direction in the drawing) orthogonal to the drawing direction of the paper trays P220, P221, and P222. The sheet P adsorbed to the conveyance belt 30 by the adsorption conveyance mechanism 3 is separated into one sheet by the action of floating air blown from the blowout port 40 and separation air blown from the blowout port 50. The sheet P fed out from the sheet tray P220 by the suction conveyance mechanism 3 has a nip portion at substantially the same height as the lower surface of the conveyance belt 30 wound around the driven roller below the driven roller group 33 shown in FIG. Nipped between the transport roller 37 and the driven roller 38.

  The paper P sandwiched between the transport roller 37 and the driven roller 38 is transported by the transport roller 37 and the transport direction is changed downward by the action of the guide member. Next, the paper is transported downward by the transport rollers R223 to R226 constituting the vertical paper transport path, guided in the substantially horizontal direction on the left side of the drawing by the guide member, and then contacted with the transport roller R227 in the rotation stopped state. Stop in contact. Thereafter, the sheet P is fed into the image forming apparatus with the start of rotation of the transport roller 227 and the like. The transport roller R227 functions as a registration roller for taking a timing with an image forming process in the image forming apparatus 110 described later.

  Similarly, the sheet P fed from the sheet tray P221 by the suction conveyance mechanism 3 has a nip that is substantially the same height as the lower surface of the conveyance belt 30 wound around the driven rollers below the driven roller group 33 shown in FIG. Is sandwiched between a conveying roller 37 and a driven roller 38 having a portion.

  The paper P sandwiched between the transport roller 37 and the driven roller 38 is transported by the transport roller 37 and the transport direction is changed downward by the action of the guide member. Next, after being transported downward by the transport rollers R225 and R226 and guided in a substantially horizontal direction on the left side of the drawing by the guide member, the transport roller R227 is stopped by abutting the leading end against the transport roller R227 in a rotation stopped state. It is sent into the image forming apparatus with the start of rotation.

  Further, the sheet P fed from the sheet tray P222 by the suction conveyance mechanism 3 has a nip portion at substantially the same height as the lower surface of the conveyance belt 30 wound around the driven roller below the driven roller group 33 shown in FIG. Between the conveying roller 37 and the driven roller 38.

  The paper P sandwiched between the transport roller 37 and the driven roller 38 is transported by the transport roller 37 and stopped with the leading end in contact with the transport roller R227 in a rotation stopped state, and as the transport roller R227 starts rotating. It is sent into the image forming apparatus.

  According to the paper feeding unit 100 according to the present invention, since the above-described paper feeding device 1 is provided, the distance between the uppermost paper and the next paper is calculated based on the calculation result, and there is no indication of paper double feeding or unsucked failure. The signs can be recognized, and the air volume of the blower mechanism can be optimized before the double feeding of the paper or the non-adsorption failure. As a result, it is possible to prevent double feeding of sheets, and it is possible to prevent the sheet from being unsucked.

<Configuration Example of Image Forming Apparatus 110>
Next, the image forming apparatus 110 provided with the sheet feeding device 1 according to the present embodiment will be described. As shown in FIG. 14, the image forming apparatus 110 is a digital color copying machine, for example, and includes an image forming unit 114 and an image reading apparatus 111. The image forming apparatus 110 further includes a paper feeding unit 90, a fixing unit 87, and a control unit S. The image forming unit 114 is called a tandem color image forming unit, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K and a transfer unit 80.

  The image reading device 111 includes an automatic document feeder 112 and a scanning exposure device 113, and is installed on the upper part of the image forming unit 114. The document G placed on the document table of the automatic document feeder 112 is transported by a transport unit (not shown), and an image on one or both sides of the document G is scanned and exposed by the optical system of the scanning exposure device 113. Or a line image sensor 8 composed of CMOS or the like. The image data photoelectrically converted by the line image sensor 8 is subjected to analog processing, A / D conversion, shading correction, image compression processing, and the like in an image processing unit (not shown), and then exposure units 3Y, 3M, 3C, 3K. Sent to.

  An image forming unit 10Y that forms a yellow (Y) image includes a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, a primary transfer unit 5Y, and a cleaning unit 6Y around a cylindrical photosensitive drum 1Y. An image forming unit 10M that forms a magenta (M) color image includes a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer unit 5M, and a cleaning unit 6M around a cylindrical photosensitive drum 1M. An image forming unit 10C for forming a cyan (C) color image includes a charging unit 2C, an exposure unit 3C, a developing unit 4C, a primary transfer unit 5C, and a cleaning unit 6C around a cylindrical photosensitive drum 1C. An image forming unit 10K that forms a black (K) image includes a charging unit 2K, an exposure unit 3K, a developing unit 4K, a primary transfer unit 5K, and a cleaning unit 6K around a cylindrical photosensitive drum 1K. When color image data is input to the image forming apparatus 110, toner images of each color are formed from the image forming units 10Y, 10M, 10C, and 10K. When monochrome image data is input to the image forming apparatus 110, the image forming unit 110 A black toner image is formed from 10K.

  The transfer unit 80 includes an intermediate transfer belt 81, a secondary transfer unit 82, a driving roller 83, and a belt cleaning unit 84.

  The intermediate transfer belt 81 is wound around a plurality of rollers including a driving roller 83 and is rotatably supported. The photosensitive drums 1Y, 1M, 1C, 1K and the primary transfer portions 5Y, 5M, 5C, 5K press the intermediate transfer belt 81. The toner images formed on the photosensitive drums 1Y, 1M, 1C, and 1K are sequentially transferred to the intermediate transfer belt 81, and a toner image is formed on the intermediate transfer belt 81.

  The paper feeding unit 90 includes paper trays P10, P11, and P12, the paper feeding device 1 described above, a paper feeding roller 91, a registration roller 92, and the like. The sheets P accommodated in the sheet trays P10, P11, and P12 are sucked and separated one by one by the sheet feeding device 1 provided in the sheet feeding unit 90, and are stopped through the sheet feeding roller 91. Paper is fed to the roller 92. The sheet P is temporarily stopped by the registration roller 92, and the registration roller 92 starts to rotate at the timing when the position of the leading end of the sheet P and the toner image formed on the intermediate transfer belt 81 coincide with each other. The paper P is fed and a toner image is transferred onto the paper P. After the toner image is transferred to the paper P by the secondary transfer unit 82, the residual toner adhering to the intermediate transfer belt 81 is removed by the belt cleaning unit 84.

  The fixing unit 87 includes a fixing roller 88 and a pressure roller 89. The sheet P on which the toner image has been transferred is heated and pressed on the image formed on the sheet P at the nip formed between the fixing roller 88 and the pressure roller 89, so that the toner image is formed on the sheet P. It is fixed. Thereafter, the paper P is sandwiched between paper discharge rollers 93 and placed on a paper discharge tray 94 outside the apparatus.

  The control unit S includes a CPU that performs arithmetic control processing, a ROM that stores various programs, a RAM that stores various data, and the like, and performs all the controls such as a control related to a series of image forming processes. The control means S calculates the distance between the uppermost sheet and the next sheet from the image acquired by the camera 70 described in FIG. 4, and adjusts the airflow of the floating air and the separated air from the calculation result. To optimize.

  According to the image forming apparatus 110 according to the present invention, since the above-described sheet feeding device 1 is provided, the distance between the uppermost sheet and the next sheet is calculated based on the calculation result, and there is no sign of sheet double feeding or non-adsorption failure. Be able to recognize signs. Thus, the air flow of the blower mechanism can be optimized before the double feeding of the paper and the non-adsorption failure, and the double feeding of the paper and the non-adsorption failure can be prevented. Further, since the paper separation process is performed only with the floating air and the separation air, the paper feeding time can be shortened and an image can be formed at a high speed.

  In this embodiment, an image forming apparatus that forms a color image has been described. However, an image forming apparatus that forms a monochrome image may be used.

<Configuration Example of Image Forming System 120>
Next, an image forming system 120 including the paper feeding unit 100 and the image forming apparatus 110 according to the present embodiment will be described. As shown in FIG. 15, the image forming system 120 includes a paper feed unit 100 and an image forming apparatus 110.

  The image forming system 120 conveys the sheets separated and discharged one by one by the sheet feeding unit 100 shown in FIG. An image forming apparatus 110 is connected to the communication port 95, and after the image forming apparatus 110 receives the paper conveyed to the communication port 95 and performs various image forming processes, it is placed on a discharge tray outside the apparatus. The

  Since the image forming system 120 according to the present invention includes the above-described paper feeding unit 100 and the image forming apparatus 110, the distance between the uppermost sheet and the next sheet is calculated based on the calculation result, and an indication of double feeding of the sheets. And signs of unadsorbed defects. Thus, the air flow of the blower mechanism can be optimized before the double feeding of the paper and the non-adsorption failure, and the double feeding of the paper and the non-adsorption failure can be prevented. Further, since the paper separation process is performed only with the floating air and the separation air, the paper feeding time can be shortened and an image can be formed at a high speed.

  The present invention is extremely suitable when applied to an image forming apparatus provided with a paper feeding device that floats loaded paper with air and sucks it on a conveyor belt or the like.

  DESCRIPTION OF SYMBOLS 1 ... Paper feeder, 2 ... Paper mounting stand, 3 ... Adsorption conveyance mechanism, 4 ... Side guide, 5 ... Separation air mechanism, 6 ... Adsorption detection sensor, 11 ... · RAM (storage means), 20 ··· paper storage unit, 22 ··· upper limit detection sensor, 30 ··· conveyor belt, 40 · · · floating air outlet, 41 and 51 · · · blower fan, 45 · ..Floating air mechanism, 50... Separation air outlet, 70... Camera (image acquisition means), 100... Paper feeding unit, 110. S, S1... Control means

Claims (10)

In the paper feeding device that sucks the uppermost paper loaded on the paper loading table on which the paper is loaded from the upper surface and sucks it on the suction surface, and transports the paper sucked on the suction surface to the paper transport path,
A blower mechanism for blowing air to the paper with a predetermined air volume;
Image acquisition means for acquiring an image between the uppermost sheet on which air is blown by the blowing mechanism and the next sheet;
And a control unit that calculates a distance between the uppermost sheet and the next sheet from the image acquired by the image acquisition unit. The control means includes
The sheet feeding device according to claim 1, wherein an air volume of the blower mechanism is adjusted according to the calculated distance. The image acquisition means includes
Acquire images for a predetermined time,
The control means includes
The distance corresponding to the predetermined time is continuously calculated, a time integration value obtained by integrating the distance with time is calculated from the calculation result, and the air volume of the blower mechanism is calculated according to the calculated time integration value. The paper feeding device according to claim 1, wherein the paper feeding device is adjusted. The image acquisition means includes
Acquire images for a predetermined time,
The control means includes
The distance corresponding to the predetermined time is calculated, a time average value obtained by averaging the distances with time is calculated from the calculation result, and the air volume of the blower mechanism is adjusted according to the calculated time average value. The paper feeding device according to claim 1. The air blowing mechanism is
A floating air mechanism that blows air at a predetermined air volume onto the paper loaded on the paper mounting table;
The sheet feeding device according to claim 1, further comprising a separation air mechanism that blows air to the sheet adsorbed on the adsorption surface with a predetermined air volume. The control means is provided with storage means for storing a predetermined time integral value or time average value,
The control means includes
The calculated time integrated value or time average value is compared with the predetermined time integrated value or time average value stored in the storage means, and the calculated time integrated value or time average value is the predetermined time integrated value or time average value. If smaller, decrease the air volume of the floating air mechanism,
6. The air volume of the floating air mechanism is increased when the calculated time integral value or time average value is greater than a predetermined time integral value or time average value. The paper feeder described. The control means is provided with storage means for storing a predetermined time integral value or time average value,
The control means includes
The calculated time integrated value or time average value is compared with a predetermined time integrated value or time average value stored in the storage means, and the calculated time integrated value or time average value is a predetermined time integrated value or time average value. If smaller, increase the air volume of the separation air mechanism,
6. The air volume of the separation air mechanism is decreased when the calculated time integral value or time average value is larger than a predetermined time integral value or time average value. The paper feeder described. One or more paper trays in which paper is stored and the uppermost paper loaded on the paper tray on which the paper is stacked in the paper tray are sucked from the top surface and sucked to the suction surface and sucked to the suction surface In the paper feed unit that transports the used paper to the paper transport path,
A blower mechanism for blowing air to the paper with a predetermined air volume;
Image acquisition means for acquiring an image between the uppermost sheet on which air is blown by the blowing mechanism and the next sheet;
And a control unit that calculates a distance between the uppermost sheet and a next sheet from the image acquired by the image acquisition unit. An image forming unit that forms an image on a sheet, and the uppermost sheet loaded on the sheet loading table on which the sheet is loaded is sucked from the upper surface to be sucked to the suction surface, and the paper sucked on the suction surface is In the image forming apparatus transported to the transport path,
A blower mechanism for blowing air to the paper with a predetermined air volume;
Image acquisition means for acquiring an image between the uppermost sheet on which air is blown by the blowing mechanism and the next sheet;
An image forming apparatus comprising: a control unit that calculates a distance between the uppermost sheet and a next sheet from an image acquired by the image acquisition unit. An image forming apparatus that forms an image on a sheet; and an uppermost sheet loaded on a sheet placing table on which the sheet is loaded is sucked from an upper surface to be sucked to a suction surface, and the paper sucked to the suction surface is An image forming system comprising: a sheet feeding device that conveys the image forming apparatus; and a control unit that performs control of supplying paper from the sheet feeding device to the image forming apparatus and forming an image on the image forming apparatus
The paper feeder is
A blower mechanism for blowing air to the paper with a predetermined air volume;
Image acquisition means for acquiring an image between the uppermost sheet on which air is blown by the blower mechanism and the next sheet;
The control means includes
An image forming system, wherein a distance between the uppermost sheet and a next sheet is calculated from an image acquired by the image acquisition unit.

Images