JP2011006158A - Paper feeder and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect abnormality of a paper feeder without using a special device.SOLUTION: A lifting plate position storage part 911 stores at predetermined time intervals the positions of a lifting plate measured by a remainder detection sensor 51, from the time a motor 95 starts to ascend until an upper limit detection sensor 39 detects that the upper surface of a bundle of papers S is located at a feed position. A position comparison part 912 compares the current position of the lifting plate and the latest measured position of the lifting plate stored in the lifting plate position storage part 911. When the current position of the lifting plate is identical to the latest measured position of the lifting plate stored in the lifting plate position storage part 911, an abnormality determination part 913 determines that an abnormality occurs in a paper feeder unit 19.

Description

  The present invention relates to a sheet feeding device that stores and feeds a sheet bundle, and an image forming apparatus including the sheet feeding device.

  A paper feeding device used in an image forming apparatus such as a copying machine, a facsimile machine, or a printer is configured to feed paper one by one from a paper bundle stored in the paper feeding device. An image fed to an image forming unit in the image forming apparatus and subjected to image forming processing is transferred.

  In general, a sheet feeding device has an elevating plate and a motor that drives the elevating plate in the vertical direction. A sheet bundle is placed on the elevating plate, and the elevating plate is raised by driving the motor. Then, when the uppermost sheet of the sheet bundle reaches a predetermined sheet feeding position (for example, a contact position with the pickup roller), the driving of the motor is stopped and the lifting plate is also stopped.

  In such a sheet feeding device, when a foreign substance is mixed inside and the foreign substance interferes with the movement of the lifting plate and the lifting plate is raised, the paper does not reach a predetermined feeding position. However, there is a problem that the motor continues to be supplied to the motor and the motor is damaged because the elevating plate is continuously raised until it reaches the sheet feeding position.

  Therefore, Patent Document 1 describes a method of measuring the current value of a motor and stopping the driving of the image forming apparatus when it is detected that an abnormal current is flowing in the motor.

Japanese Patent Laid-Open No. 05-197229

  However, the method of Patent Document 1 requires a dedicated signal line and measuring device for measuring the current flowing through the motor. Therefore, there has been a problem in cost due to an increase in the number of parts.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet feeding device and an image forming apparatus that detect an abnormality of the sheet feeding device without using a special device. is there.

  The invention according to claim 1 is a paper feeding device that feeds the recording medium stored in the recording medium storage unit to the outside, the transporting means for feeding the recording medium one by one and transporting the recording medium to the outside, Lifting means for lifting the recording medium to a position abutting on the conveying means, driving means for lifting the lifting means, drive control means for controlling drive of the driving means, and a position where the recording medium abuts on the conveying means An upper limit detecting means for detecting whether or not there is, a position measuring means for detecting a position of the elevating means in the elevating direction, and the upper limit detecting means from which the elevating means is started to rise by the driving means. Position storage means for storing the position of the elevating means detected by the position measuring means at predetermined time intervals until it is detected that the position is in contact with the conveying means; Comparing means for comparing the position of the lifting means detected by the means with the position of the lifting means measured by the position measuring means last time stored in the position storage means; When the position of the lifting / lowering means coincides with the previous position of the lifting / lowering means stored in the position storage means, the determination means for determining that an abnormality has occurred in the sheet feeding device, and display control for performing display control of the display unit And when the determination means determines that an abnormality has occurred, the drive control means stops the drive of the drive means.

  According to this configuration, the lifting / lowering means is raised after the lifting / lowering means is raised until the upper limit detection means detects that the recording medium has come into contact with the conveying means (until the recording medium is lifted up to a feedable position). By detecting the position of the elevating means at a predetermined time and comparing the position of the elevating means at the time of detection with the previous detection, it is detected whether the elevating means is normally raised without using a special device. Can do. That is, when the position of the lifting / lowering means at the time of detection is the same as that at the previous detection, it indicates that the lifting / lowering means has stopped and an abnormality has occurred in the sheet feeding device. Then, the drive control means immediately stops the drive means. As a result, it is possible to solve the problem that the drive means is damaged due to continuous supply of current to the drive means.

  According to a second aspect of the present invention, in the paper feeding device according to the first aspect, the determination unit determines that an abnormality has occurred in the paper feeding device, and the drive control unit controls driving of the driving unit. After stopping, the position storage means stores the position of the elevating means, and then the drive control means drives the driving means to raise again after returning the elevating means to the initial position, The elevating means stores in the position storage means from the start of the ascent of the elevating means by the driving means until the upper limit detecting means detects that the recording medium is in a position in contact with the conveying means. When the vehicle stops at the same position as the position, the determination means determines that foreign matter is mixed in the paper feeding device.

  According to this configuration, the lifting / lowering means is stopped until the upper limit detecting means detects that the recording medium has come into contact with the conveying means (first rise) after the lifting / lowering means is lifted. When the lifting / lowering means rises again after returning to the initial position (second rise), if the lifting / lowering means stops at the same position for the first and second times, foreign matter mixed in the paper feeder rises in the lifting / lowering means. There is a high possibility of disturbing. Thus, by comparing the stop positions of the first and second lifting / lowering means, the cause of the lifting / lowering means stopping can be identified.

  A third aspect of the present invention is the paper feeding device according to the second aspect, further comprising warning message storage means for storing a warning message according to the type of abnormality of the paper feeding apparatus, wherein the judging means When it is determined that foreign matter is mixed in the paper feeding device, the display control means reads out a warning message indicating that foreign matter is mixed in the paper feeding device from the warning message storage means. It is displayed on the display unit.

  According to this configuration, the warning message storage means stores a warning message according to the type of abnormality of the sheet feeding device, so that the display control means displays a warning message according to the cause of the lifting / lowering means stopping (contamination of foreign matter). The user can immediately take action according to the cause of the abnormality.

  According to a fourth aspect of the present invention, in the paper feeding device according to the first or second aspect, the determination unit determines that an abnormality has occurred in the paper feeding device, and the drive control unit controls the driving unit. After stopping the driving, the position storage means stores the position of the elevating means, and then the drive control means drives the driving means to return the elevating means to the initial position and then raise it again. The elevating means moves from the start of the raising / lowering means by the driving means to the time when the upper limit detecting means detects that the recording medium is in a position in contact with the conveying means. When stopping at a position different from the position stored in, the determination means determines that the drive means is out of order, and the drive control means stops the drive of the drive means.

  According to this configuration, the lifting / lowering means stops and the lifting / lowering means rises until the upper limit detection means detects that the recording medium has come into contact with the conveying means (the first rise) after the lifting / lowering means is raised. Until the upper limit detecting means detects that the recording medium has come into contact with the conveying means (first rise), and the first and second raising / lowering means have different stop positions. There is a high possibility that the drive means for raising the elevating means is out of order. By comparing the stop positions of the first and second lifting / lowering means, the cause of the lifting / lowering means stopping can be identified.

  The invention according to claim 5 is the sheet feeding device according to claim 4, further comprising warning message storage means for storing a warning message according to the type of abnormality of the sheet feeding apparatus, wherein the judging means When it is determined that the driving unit is out of order, the display control unit reads out a warning message indicating that the driving unit is out of order from the warning message storage unit and displays the warning message on the display unit. .

  According to this configuration, the warning message according to the type of abnormality of the sheet feeding device is stored in the warning message storage means, so that the display control means can issue a warning message according to the cause of the lifting / lowering means stopping (failure of the driving means). Can be displayed on the display unit, and the user can take immediate action according to the cause of the abnormality.

  A sixth aspect of the present invention is the paper feeding device according to any one of the first to fifth aspects, wherein the comparison means is stored in the current position of the lifting means and the previous position storage means. When the position of the lifting / lowering means does not match, the position of the lifting / lowering means per unit time is determined from the difference between the current position of the lifting / lowering means and the previous position of the lifting / lowering means stored in the position storage means. Calculation means for calculating a change amount is further provided, and the determination means determines whether or not the calculated change amount is smaller than a predetermined change amount.

  If, for example, an elastic soft foreign matter is mixed in the sheet feeding device instead of a hard foreign matter, the foreign matter may be deformed as the elevating means rises, and the elevating means may rise even slowly. In addition, there is a possibility that the ascending / descending speed of the elevating / lowering unit may be lower than that at the normal time due to a failure of the driving unit.

  Therefore, the amount of change per unit time when the lifting / lowering means ascends in the normal state is measured in advance, and a predetermined value (for example, a value calculated from variations in the rising speed of the lifting / lowering means, etc.) is subtracted from the normal change amount The value is a predetermined amount of change. Then, the amount of change per predetermined time of the lifting / lowering means is calculated when the lifting / lowering means is raised. When the amount of change is smaller than a predetermined amount of change, it indicates that the lifting / lowering means is slowly rising, and there is a possibility that an abnormality has occurred in the sheet feeding device. Thus, by detecting an event that may be abnormal, the abnormality detection accuracy of the paper feeding device can be improved.

  According to a seventh aspect of the present invention, in the paper feeding device according to the sixth aspect, when the determination unit determines that the calculated change amount is smaller than a predetermined change amount, the display control unit Reads out a warning message indicating that there is a possibility that an abnormality has occurred in the paper feeding device from the warning message storage means and displays it on the display unit.

  According to this configuration, when the lifting / lowering means is slowly rising, the display control means displays a warning message indicating that there is a “possibility” that an abnormality has occurred in the paper feeding device on the display unit, By making the text different from the warning message displayed when the elevating means is completely stopped, it is possible to inform the user of the urgency of the abnormality that has occurred in the paper feeder.

  According to an eighth aspect of the present invention, there is provided an image forming apparatus according to any one of the first to seventh aspects, and an image forming unit that forms an image on a recording medium fed by the paper feeding apparatus. And.

  According to this configuration, the same effects as in the first to seventh aspects can be achieved.

  According to the present invention, the elevating means is raised between when the elevating means is raised and until the upper limit detecting means detects that the recording medium is in contact with the conveying means (until the recording medium is lifted to a position where the recording medium can be fed). By detecting the position of the elevating means at a predetermined time and comparing the position of the elevating means at the time of detection with the previous detection, it is detected whether the elevating means is normally raised without using a special device. Can do. That is, when the position of the lifting / lowering means at the time of detection is the same as that at the previous detection, it indicates that the lifting / lowering means has stopped and an abnormality has occurred in the sheet feeding device. Then, the drive control means immediately stops the drive means. As a result, it is possible to solve the problem that the drive means is damaged due to continuous supply of current to the drive means.

FIG. 2 is a side view schematically showing an internal configuration of the image forming apparatus. Sectional drawing which shows the structure of a paper feed unit. The perspective view of a paper feed unit. FIG. 4 is an explanatory diagram illustrating an upper limit detection sensor mounted on a paper feeding unit. 1 is a block diagram illustrating an electrical configuration of an image forming apparatus. 6 is a flowchart illustrating a flow of an abnormality detection process for a paper feeding unit according to the first embodiment. 6 is a flowchart illustrating a flow of an abnormality detection process for a paper feeding unit according to the first embodiment. The example of a screen displayed on a display part. 9 is a flowchart showing a flow of abnormality detection processing of a paper feeding unit in the second embodiment. 9 is a flowchart showing a flow of abnormality detection processing of a paper feeding unit in the second embodiment. The example of a screen displayed on a display part.

[First Embodiment]
Hereinafter, a first embodiment of an image forming apparatus including a sheet feeding device of the present invention will be described with reference to the drawings. FIG. 1 is a side view schematically showing an internal configuration of an image forming apparatus 1 including a paper feeding unit 19 which is a paper feeding device according to the present invention. The image forming apparatus 1 is a multifunction device having functions such as a copy function, a printer function, a scanner function, and a facsimile function. The image forming apparatus 1 includes a main body 2, a stack tray 3 disposed on the left side of the main body 2, and a main body. The document reading unit 4 is disposed above the unit 2, and the document feeding unit 5 is disposed above the document reading unit 4.

  An input operation unit 6 is provided on the front part of the image forming apparatus 1. The input operation unit 6 displays a start key 7 for a user to input a print execution instruction, a numeric keypad 8 for inputting the number of copies to be printed, operation guide information for various copying operations, and the like. A display unit 9 composed of a liquid crystal display or the like having a touch panel function for input, a reset key 10 for resetting setting contents set on the display unit 9, and a stop for stopping a printing (image forming) operation being executed A key 11 and a function switching key 12 for switching between a copy function, a printer function, a scanner function, and a facsimile function are provided.

  The document reading unit 4 includes a scanner unit 13 including an image sensor such as a charge coupled device (CCD) sensor and a complementary metal oxide semiconductor (CMOS) sensor and an exposure lamp, a document table 14 formed of a transparent member such as glass, and the like. A document reading slit 15 is provided. The scanner unit 13 is configured to be movable by a driving unit (not shown). When reading a document placed on the document table 14, the scanner unit 13 is moved along the document surface at a position facing the document table 14 to scan the document. While acquiring the image data. When reading the document fed by the document feeding unit 5, the document is moved to a position facing the document reading slit 15 and synchronized with the document feeding operation by the document feeding unit 5 via the document reading slit 15. The image of the original is scanned to obtain image data.

  The document feeder 5 includes a document placement unit 16 for placing a document, a document discharge unit 17 for ejecting an image-read document, and a document placed on the document placement unit 16. A document transport mechanism 18 including a paper feed roller, a transport roller (not shown), and the like for feeding the paper one by one to a position facing the document reading slit 15 and discharging it to the document discharge section 17 is provided.

  Further, the document feeding unit 5 is provided so as to be rotatable with respect to the main body unit 2 so that the front side thereof can move upward. By moving the front side of the document feeder 5 upward to open the upper surface of the document table 14, the user can place a read document, for example, a book in a spread state, on the upper surface of the document table 14. ing.

  The main body 2 includes a plurality of paper feeding units 19, a pickup roller 20 that feeds the paper from the paper feeding unit 19 one by one and transports the paper to the image forming unit 21, and an image on the paper transported from the paper feeding unit 19. And an image forming unit 21 to be formed.

  The image forming unit 21 outputs a laser beam or the like based on the image data acquired by the scanner unit 13 to expose the photosensitive drum 22, and forms an electrostatic latent image on the surface of the photosensitive drum 22. A developing unit 24 that forms a toner image by attaching toner to the surface of the photosensitive drum 22 on which the electrostatic latent image is formed; a transfer unit 25 that transfers the toner image on the photosensitive drum 22 to a sheet; A fixing device 28 having a fixing roller 26 and a pressure roller 27 for fixing the toner image to the paper by heating the paper on which the toner image has been transferred, and a paper conveying path in the image forming unit 21. A pair of conveyance rollers 30 and 31 for conveying the stack tray 3 or the discharge tray 29 is provided.

  When images are formed on both sides of a sheet, the image forming unit 21 forms an image on one side of the sheet, and then the sheet is nipped between the pair of conveying rollers 30 on the discharge tray 29 side. In this state, the conveyance roller pair 30 is reversed to switch back the sheet, and the sheet is sent to the sheet conveyance path 32 to be conveyed again to the upstream area of the image forming unit 21. The image forming unit 21 forms an image on the other surface. After that, the paper is discharged to the stack tray 3 or the discharge tray 29.

  Next, the paper feeding unit 19 will be described in detail. FIG. 2 is a cross-sectional view showing the configuration of the paper feed unit 19. FIG. 3 is a perspective view of the paper feeding unit 19. FIG. 4 is an explanatory diagram showing the upper limit detection sensor 39 mounted on the paper feeding unit 19.

  As shown in FIGS. 2 and 3, the paper feed unit 19 includes an elevating plate 61 on the inner bottom surface of the paper storage unit 35 on which a paper bundle S composed of a plurality of papers P is stacked. The lifting plate 61 is rotatably supported at its upstream end (left end portion in FIG. 2) in the sheet feeding direction by a support portion 38. In other words, the elevating plate 61 is rotatable in the vertical plane by the support portion 38 with the downstream end as a free end inside the paper storage portion 35. The support portions 38 are provided on both side walls of the paper storage portion 35 that is disposed so as to face the width direction of the paper P (a direction orthogonal to the paper feeding direction).

  The paper feed cassette 130A of the paper feed unit 19 includes width alignment cursor pairs 34a and 34b for positioning the paper P stored in the paper storage unit 35 in the width direction, and a rear end cursor 33 for aligning the rear ends of the paper P. ing. The width alignment cursor pairs 34a and 34b are provided so as to be able to reciprocate in the sheet width direction (arrow A direction in FIG. 3), respectively, along a guide rail (not shown). Further, since the paper P is sent out in the direction of arrow B, the rear end cursor 33 is provided so as to be capable of reciprocating along the guide rails 33a and 33b in parallel with the sheet conveying direction (in the direction of arrow B in FIG. 3). The sheet bundle S can be stored in a predetermined position in the sheet feeding unit 19 by moving the width alignment cursor pairs 34a and 34b and the rear end cursor 33 according to the sheet size to be stacked. Further, the paper feeding unit 19 includes a cassette cover 43, and the surface side (side seen from the direction of arrow C in FIG. 3) is exposed to the outside and constitutes a part of the exterior surface of the image forming apparatus 1.

  A drive shaft 36, a push-up member 62, and a drive connecting member (not shown) are provided below the lift plate 61 in the sheet feeding direction downstream as a lift mechanism for moving the lift plate 61 up and down. Further, a receiving member (not shown) corresponding to the drive connecting member and a motor (not shown) capable of rotating forward and backward connected to the receiving member are provided on the sheet feeding unit main body 130B side. In a state where the paper feed cassette 130A is housed in the paper feed unit main body 130B, the drive connecting member of the paper storage unit 35 on the paper feed cassette 130A side is engaged with and connected to the receiving member on the paper feed unit main body 130B side. Thereby, the power of the motor can be transmitted to the drive shaft 36. The drive shaft 36, the push-up member 62, the drive connecting member, the receiving member, and the motor constitute an elevating mechanism that displaces the elevating plate 61 between the paper feeding position and the retracted position.

  Here, the paper feed position is a position where the elevating plate 61 is raised and the upper surface of the sheet bundle S placed on the elevating plate 61 comes into contact with the pickup roller 20 and can be fed. The retreat position is a position where the elevating plate 61 is lowered to the bottom. In addition, as a motor which comprises the raising / lowering mechanism which raises / lowers the raising / lowering board 61, a stepping motor, a DC motor, etc. can be used, for example.

  As shown in FIG. 2, the paper feed unit 19 includes a paper feed roller 41 provided on the downstream side in the transport direction of the pickup roller 20, and a separating roller 42 provided below the paper feed roller 41. Yes. Further, a transport roller 37 is provided on the downstream side in the transport direction of the pickup roller 20 and the paper feed roller 41.

  The paper feed roller 41 feeds the paper P taken out by the pickup roller 20 to the transport roller 37. The paper feed roller 41 rotates in a direction in which the paper P can be conveyed downstream, whereas the separating roller 42 rotates in a direction in which the paper P is sent back upstream. Even if the paper P picked up by the pickup roller 20 is overlapped, the separating roller 42 can prevent paper other than the uppermost paper P from being fed in the direction of the transport roller 37, and only the uppermost paper P can be prevented. Is conveyed to the conveyance roller 37 by the paper feed roller 41.

  Further, as shown in FIGS. 4A and 4B, the paper feed unit 19 detects that the uppermost paper P of the paper bundle S placed on the lifting plate 61 is at the paper feed position. An upper limit detection sensor 39 is provided. The upper limit detection sensor 39 includes a light shielding member 39A and an optical sensor 39B. The optical sensor 39B includes a light emitting element fixedly provided near the pickup roller 20 and a light receiving element that receives light emitted from the light emitting element. On the other hand, the light shielding member 39 </ b> A is provided on the support member 50 of the pickup roller 20. Further, the support member 50 is provided so as to be rotatable about the rotation axis of the paper feed roller 41. As a result, when the upper surface of the sheet bundle S placed on the lifting plate 61 moves to the paper feeding position shown in FIG. 4B due to the lifting of the lifting plate 61, the pickup roller 20 pushes up to the uppermost sheet P. Then, it rotates around the rotation axis of the paper feed roller 41 and is displaced slightly upward. At this time, the light blocking member 39A is lifted upward in conjunction with the pickup roller 20, and the optical path of the optical sensor 39B is blocked to detect that the upper surface of the sheet bundle S is at the paper feed position.

  In the sheet feeding unit 19 having such a configuration, the push-up member 62 pushes up the downstream end side of the lift plate 61 while engaging the bottom surface of the lift plate 61 by the operation of the motor. As a result, the upper surface of the sheet bundle S stacked on the lifting plate 61 is displaced to the paper feed position where it contacts the pickup roller 20 provided above the paper feed cassette 130A. As shown in FIG. 4B, when the upper limit detection sensor 39 detects the displacement of the pickup roller 20 to the paper feeding position, the driving of the motor is stopped. When the upper limit detection sensor 39 is not detected due to the decrease of the paper P during paper feeding, the motor is operated to lift the paper bundle S to the paper feeding position.

  In this embodiment, the support member 50 of the pickup roller 20 is provided with the light shielding member 39A as a detected portion, but the present invention is not limited to this. For example, the upper surface of the sheet bundle S near the pickup roller 20 may be directly detected, or the detection mechanism itself may be an element using elements other than the optical sensor.

  In addition, a remaining amount detection sensor 51 that detects the remaining amount of the sheet bundle S by measuring the distance to the lifting plate 61 is disposed at the bottom of the sheet feeding cassette 130A. As shown in FIG. 3, the remaining amount detection sensor 51 is located on either side of the side surface of the push-up member 61 in the direction of arrow A so that the push-up member 62 is not positioned between the remaining amount detection sensor 51 and the lifting plate 61. Placed in position. In FIG. 3, two remaining amount detection sensors 51 are illustrated for explanation, but any one of them may actually be employed. The remaining amount detection sensor 51 is desirably a distance measuring sensor using a triangulation method, but is not limited thereto.

  The remaining amount detection sensor 51 measures the distance to the lift plate 61 and outputs the measurement result to a control unit described later. From this measurement result, the control unit calculates, for example, the thickness of the sheet bundle S, and calculates the number of sheets in the sheet bundle S by dividing the thickness of the sheet bundle S by the thickness per sheet P. . The calculation method will be described later. Hereinafter, the distance from the remaining amount detection sensor 51 measured by the remaining amount detection sensor 51 to the lifting plate 61 is expressed as “the position of the lifting plate 61”.

  The measurement result of the remaining amount detection sensor 51 is used to determine whether or not foreign matter is mixed in the sheet feeding unit 19 in addition to detecting the remaining amount of sheets in the sheet feeding unit 19. Specifically, when the motor raises the elevating plate 61 but the upper limit detection sensor 39 does not detect the light blocking member 39A (that is, when the upper surface of the sheet bundle S has not reached the sheet feeding position), it will be described later. The control unit that compares the measurement results (positions of the lifting plate 61) of the remaining amount detection sensor 51 every predetermined time. If the position of the elevating plate 61 is the same before and after a predetermined time, there is a high possibility that a motor failure or foreign matter mixed in the paper feeding unit 19 prevents the elevating plate 61 from rising. In this case, since the motor tries to keep raising the elevating plate 61 until the upper surface of the sheet bundle S reaches the paper feeding position, there is a problem that current is continuously supplied to the motor and heat is generated and damaged.

  Therefore, the control unit compares the position of the lifting plate 61 until the upper surface of the sheet bundle S reaches the sheet feeding position, so that it is determined whether the motor is broken or foreign matter is mixed into the sheet feeding unit 19 and an abnormality is detected. If this happens, stop the motor immediately. Hereinafter, a method for detecting an abnormality in the paper feeding unit 19 will be described in detail.

  FIG. 5 is a block diagram showing an electrical configuration of the image forming apparatus 1. The image forming apparatus 1 includes a control unit 91, a storage unit 92, a document reading unit 4, an image memory 93, an image processing unit 94, an image forming unit 21, a paper feeding unit 19, an input operation unit 6, and a network I / F unit 96. It is prepared for. In addition, the same code | symbol is attached | subjected to the same component demonstrated using FIGS. 1-4, and description is abbreviate | omitted. The elements indicated by dotted lines are elements used in the second embodiment, and thus are not described in the present embodiment.

  The storage unit 92 stores programs, data, and the like for realizing various functions of the image forming apparatus 1, and functions as a warning message storage unit 921 in the present embodiment. The warning message storage unit 921 stores warning message data for notifying the user of abnormality in the paper feeding unit 19 for each cause.

  The image memory 93 temporarily stores image data acquired by the document reading unit 4 and image data transmitted from an external apparatus via the network I / F unit 96. The image processing unit 94 performs image processing such as image correction and enlargement / reduction on the image data stored in the image memory 93.

  The motor 95 of the paper feed unit 19 is a drive source that displaces the push-up member 62 (moves the elevating plate 61 up and down). The network I / F unit 96 includes a communication module such as a LAN board, and transmits / receives various data to / from an external device via a network (not shown) connected to the network I / F unit 96.

  The control unit 91 is configured by a CPU (Central Processing Unit) and the like, reads a program stored in the storage unit 92 and executes processing, and outputs an instruction signal to each functional unit, data transfer, and the like. The image forming apparatus 1 is comprehensively controlled to have an elevator plate position storage unit 911, a position comparison unit 912, an abnormality determination unit 913, and a display control unit 914.

  The lift plate position storage unit 911 stores the position of the lift plate 61 measured by the remaining amount detection sensor 51 every predetermined time until the sheet bundle S reaches the paper feed position. The position comparison unit 912 has a position of the lifting plate 61 around a predetermined time (the latest lifting plate 61 position measured by the remaining amount detection sensor 51 and the position of the lifting plate 61 stored in the lifting plate position storage unit 911). Compare

  The abnormality determination unit 913 determines an abnormality in the paper feeding unit 19 based on the comparison result by the position comparison unit 912. A simple flow of abnormality detection in the paper feeding unit 19 will be described. First, until the sheet bundle S reaches the paper feed position, the position comparison unit 912 stores the latest position of the lift plate 61 measured by the remaining amount detection sensor 51 and the lift plate position storage unit 911. The positions of the lift plates 61 are compared to determine whether or not the positions are the same. If they are the same, the abnormality determination unit 913 determines that an abnormality has occurred in the paper feeding unit 19, and the control unit 91 temporarily stops the motor 95. Thereafter, the controller 91 controls the motor 95 to move the elevating plate 61 to the retracted position and raise it for the second time.

  In the first rise and the second rise of the lift plate 61, when the lift plate 61 stops at the same position, the abnormality determination unit 913 determines that foreign matter is mixed in the paper feed unit 19. On the other hand, when the elevating plate 61 stops at a different position, the abnormality determination unit 913 determines that the motor 95 has failed. The controller 91 stops the motor 95 after detecting these abnormalities.

  The display control unit 914 reads out from the warning message storage unit 921 a warning message that informs the user that the motor 95 has failed or that a foreign substance is mixed in the paper feeding unit 19 and causes the display unit 9 to display the warning message.

  6 and 7 are flowcharts showing the flow of the abnormality detection process of the paper feeding unit 19 in the present embodiment. When the paper feeding unit 19 is attached to the main body 2 (step S11; YES), the remaining amount detection sensor 51 measures the position of the lifting plate 61 and outputs the measurement result to the control unit 91. And the control part 91 memorize | stores this measurement result in the raising / lowering board position memory | storage part 911 (step S12).

  Next, the control part 91 drives the motor 95 and raises the raising / lowering board 61 (step S13). Here, until the controller 91 recognizes that the upper surface of the sheet bundle S is at the paper feed position in step S14 or until it detects an abnormality in the paper feed unit 19 and stops the motor 95 in step S17. In order to continue raising the elevating plate 61 at a predetermined speed, drive control is performed on the motor 95.

  When the upper surface of the sheet bundle S has reached the sheet feeding position, that is, when the upper limit detection sensor 39 detects the light shielding member 39A (step S14; YES), the control unit 91 sets the sheet bundle S to the sheet feeding position normally. It is determined that the motor 95 has been stopped (step S25), and the process is terminated.

  When the upper surface of the sheet bundle S is not at the paper feed position, that is, when the upper limit detection sensor 39 has not detected the light shielding member 39A (step S14; NO), the remaining amount detection sensor 51 is t seconds after the start of the rise (t is The position of the lifting / lowering plate 61 (an integer greater than or equal to 0) is measured, and the measurement result is output to the control unit 91 (step S15). The initial value of the variable t is a predetermined value (an integer greater than or equal to 0).

  And the position comparison part 912 compares the position of the raising / lowering board 61 memorize | stored in the raising / lowering board position memory | storage part 911, and the position of the raising / lowering board 61 measured by step S15 (step S16). When the positions are different (step S16; NO), the control unit 91 updates and stores the position of the lift plate 61 measured in step S15 in the lift plate position storage unit 911, and sets a predetermined constant t0 ( t0 is an integer greater than 0) (step S18). Then, the control unit 91 again determines whether or not the upper surface of the sheet bundle S has reached the paper feed position. If not, the remaining amount detection sensor 51 determines the position of the lift plate 61 after t seconds from the start of ascent. taking measurement.

  Here, for example, when the initial value of the variable t is 1 second and the constant t0 is 0.5 seconds, the first measurement of the lifting plate 61 is 1 second after the start of ascent, and the second and subsequent times at 0.5 second intervals. Will be measured. Thus, the processes in steps S14 to S16 and step S18 are repeated until the upper surface of the sheet bundle S reaches the sheet feeding position.

  On the other hand, when the position of the lift plate 61 stored in the lift plate position storage unit 911 is the same as the position of the lift plate 61 measured in step S15 (step S16; YES), the abnormality determination unit 913 determines the paper feed unit. 19 determines that an abnormality has occurred, and the controller 91 once stops the motor 95. Further, the control unit 91 stores the position of the lifting plate 61 measured in step S15 in the lifting plate position storage unit 911 (step S17), and causes the motor 95 to return the lifting plate 61 to the retracted position (step S18). .

  And the control part 91 raises the raising / lowering board 61 with respect to the motor 95 again (step S19). Here, in the same manner as described above, the control unit 91 determines the cause of the abnormality of the paper feeding unit 19 until it recognizes in step S24 that the upper surface of the sheet bundle S is at the paper feeding position or in step S22 or S23. In order to continue raising the elevating plate 61 at a predetermined speed, drive control is performed on the motor 95.

  The control unit 91 determines whether or not the lifting plate 61 has stopped (step S20). If it has stopped (step S20; YES), the position of the lifting plate 61 at this time is measured by the remaining amount detection sensor 51. Thus, it is determined whether or not the stop position is the same as the position of the lift plate 61 stored in the lift plate position storage unit 911 (step S21). That is, it is checked whether or not the first lifting / lowering plate 61 stops at the same position. When the stop positions are the same (step S21; YES), the abnormality determination unit 913 determines that the foreign matter mixed in the paper feeding unit 19 is the cause, and the control unit 91 stops the motor 95. Then, the display control unit 914 reads out a warning message from the warning message storage unit 921 for notifying the user that a foreign object has entered the paper feeding unit 19 and displays the warning message on the display unit 9 (step S22). An example of the screen displayed on the display unit 9 at this time is shown in FIG.

  Further, if the stop position of the lift plate 61 is different from the position stored in the lift plate position storage unit 911 (step S21; NO), that is, if the lift plate 61 stops at a position different from the first time and this time, an abnormality The determination unit 913 determines that the motor 95 has failed, and the control unit 91 stops the motor 95. Then, the display control unit 914 reads a warning message for notifying the user of the failure of the motor 95 from the warning message storage unit 921 and displays the warning message on the display unit 9 (step S23). An example of a screen displayed on the display unit 9 at this time is shown in FIG.

  On the other hand, when the elevating plate 61 does not stop (step S20; NO), and the upper surface of the sheet bundle S reaches the sheet feeding position (step S24; YES), the control unit 91 determines that the sheet bundle S is normally fed to the sheet feeding position. Therefore, the motor 95 is stopped (step S25), and the process is terminated. When the upper surface of the sheet bundle S does not reach the sheet feeding position (step S24; NO), the control unit 91 shifts the process to step S20.

  As described above, when the lifting plate 61 stops at the first rise, it is determined that an abnormality has occurred in the paper feeding unit 19, and the lifting plate 61 stops at the same position as the first at the second rise. In this case, it is determined that the foreign matter mixed in the paper feeding unit 19 is the cause. If the elevating plate 61 is stopped at a different position, it is determined that the motor 95 is defective. The position of the elevating plate 61 is measured every predetermined time by the remaining amount detection sensor 51, and the controller 91 determines an abnormality based on the measurement result. Anomalies can be discovered.

[Second Embodiment]
In the first embodiment, when the lift plate 61 is raised for the first time, the remaining amount detection sensor 51 measures the position of the lift plate 61 every predetermined time, and the positions of the lift plate 61 at the previous measurement and the current measurement are measured. If they are the same, it indicates that the lifting plate 61 has stopped before the upper surface of the sheet bundle S reaches the sheet feeding position, and the case where it is determined that an abnormality has occurred in the sheet feeding unit 19 has been described. In the second embodiment, the amount of movement of the elevating plate 61 per predetermined time is calculated during the first ascent, and if the amount of movement is less than a predetermined reference value, A case will be described in which it is determined that foreign matter is mixed in the motor 95 and the motor 95 is stopped.

  If, for example, an elastic soft foreign matter is mixed in the paper feeding unit 19 instead of a hard foreign matter, the foreign matter may be deformed as the elevating plate 61 rises, and the elevating plate 61 may rise even slowly. . That is, since the elevating plate 61 does not stop completely, the method described in the first embodiment cannot detect an abnormality in the paper feeding unit 19. Furthermore, the raising speed of the elevating plate 61 may decrease due to a failure of the motor 95.

  Therefore, the amount of change per predetermined time when the elevating plate 61 is raised to the paper feed position in a normal state in which no foreign matter is mixed in the paper feed unit 19 is measured in advance, and from the amount of change at the normal time A value obtained by subtracting a predetermined value (a value calculated from variations in the ascending speed of the elevating plate 61) is set as a reference value. Then, when the lift plate 61 is raised for the first time, the amount of change of the lift plate 61 per predetermined time is calculated. If the change amount is less than the reference value, it indicates that the lift plate 61 is slowly rising. Therefore, it is determined that there is a possibility that an abnormality has occurred in the paper feeding unit 19, and a warning message is displayed on the display unit 9.

  Note that the mechanical configurations of the sheet conveying apparatus and the image forming apparatus in the present embodiment are the same as those described in the first embodiment with reference to FIGS. Further, the block diagram showing the electrical configuration of the image forming apparatus 1 of the present embodiment is obtained by adding the elements indicated by the dotted lines in FIG.

  That is, the storage unit 92 functions as the reference value storage unit 922. The reference value storage unit 922 is a predetermined value based on a change amount per predetermined time that is measured in advance when the elevating plate 61 is raised to the paper feed position when a foreign matter is not mixed in the paper feed unit 19. A reference value that is a value obtained by subtracting is stored. The control unit 91 further includes a change amount calculation unit 915. The change amount calculation unit 915 calculates the change amount per predetermined time of the lifting plate 61 using the measurement result output from the remaining amount detection sensor 51.

  Hereinafter, this will be described in detail with reference to flowcharts. 8 and 9 are flowcharts showing the flow of control processing of the paper feeding unit 19 in the present embodiment. In the first embodiment, the same processing as the flowcharts shown in FIGS. 6 and 7 will be briefly described, and different processing will be described in detail.

  When the paper feeding unit 19 is attached to the main body 2 (step S11; YES), the remaining amount detection sensor 51 measures the position of the lifting plate 61 and outputs the measurement result to the control unit 91. And the control part 91 memorize | stores this measurement result in the raising / lowering board position memory | storage part 911 (step S12).

  Next, the control part 91 drives the motor 95 and raises the raising / lowering board 61 (step S13). When the upper surface of the sheet bundle S has reached the sheet feeding position (step S14; YES), the control unit 91 determines that the sheet bundle S is normally set at the sheet feeding position and stops the motor 95 (step S25). End the process.

  When the upper surface of the sheet bundle S is not at the sheet feeding position (step S14; NO), the remaining amount detection sensor 51 measures the position of the lifting plate 61 t seconds after the start of ascent and outputs the measurement result to the control unit 91. (Step S15). And the position comparison part 912 compares the position of the raising / lowering board 61 memorize | stored in the raising / lowering board position memory | storage part 911, and the position of the raising / lowering board 61 measured by step S15 (step S16). When the positions are different (step S16; NO), the change amount calculation unit 915 calculates a difference between the position of the lift plate 61 stored in the lift plate position storage unit 911 and the position of the lift plate 61 measured in step S15 for a predetermined time. Dividing by (for example, 0.1 second), the amount of change per predetermined time is calculated (step S31).

  Subsequently, the control unit 91 compares the calculated change amount with the reference value stored in the reference value storage unit 922. If the movement amount is equal to or greater than the reference value (step S32; NO), the measurement is performed in step S15. The position of the lift plate 61 is updated and stored in the lift plate position storage unit 911 (step S18), a predetermined constant t0 is added to the variable t (step S18), and the process proceeds to step S14.

  On the other hand, if the movement amount is less than the reference value (step S32; YES), the abnormality determination unit 913 determines that there is a possibility that an abnormality has occurred in the paper feeding unit 19, and stops the motor 95. Then, the display control unit 914 reads out a warning message from the warning message storage unit 921 for notifying the user of the possibility of abnormality in the paper feeding unit 19 and displays it on the display unit 9 (step 33), and ends the process. . An example of the screen displayed on the display unit 9 at this time is shown in FIG. The screen example in FIG. 11 is a screen example that is displayed when there is a high possibility that an elastic foreign matter has entered the paper feed unit 19. If the motor 95 is highly likely to fail, It is desirable to display a message prompting contact.

  When the first and second lifting / lowering plates 61 are stopped at the same position as described in the first embodiment, the foreign matter mixed in the paper feeding unit 19 interferes with the lifting / lowering plate 61 at the same position. Since the possibility of the stop is extremely high, as shown in FIG. 8A, the warning message is “foreign matter is mixed in”.

  However, if the amount of change per predetermined time of the elevating plate 61 described in the present embodiment is less than the reference value, there is a possibility that elastic soft foreign matter has been mixed, but for example, the sheet bundle S is correct. It is also conceivable that the sheet bundle S is not placed at the position, and the amount of change per predetermined time of the elevating plate 61 is small due to the obstacle. Therefore, as a warning message displayed in such a case, “There is a“ possibility ”that foreign matter is mixed in”. In this way, by changing the text of the warning message, it is possible to inform the user of the urgency of the abnormality that has occurred in the paper feed unit 19.

  Returning to FIG. When the position of the lift plate 61 stored in the lift plate position storage unit 911 is the same as the position of the lift plate 61 measured in step S15 (step S16; YES), the abnormality determination unit 913 sends the error determination unit 913 to the paper feed unit 19. The controller 91 determines that an abnormality has occurred and temporarily stops the motor 95. Further, the position of the lift plate 61 measured in step S15 is stored in the lift plate position storage unit 911 (step S17), and the lift plate 61 is returned to the retracted position by the motor 95 (step S18).

  And the control part 91 raises the raising / lowering board 61 with respect to the motor 95 again (step S19), discriminate | determines whether the raising / lowering board 61 stopped (step S20), and if it has stopped (step S20; YES), the position of the lift plate 61 at this time is measured by the remaining amount detection sensor 51, and it is determined whether or not the stop position is the same as the position of the lift plate 61 stored in the lift plate position storage unit 911. (Step S21). When the stop positions are the same (step S21; YES), the abnormality determination unit 913 determines that the foreign matter mixed in the paper feeding unit 19 is the cause, and the control unit 91 stops the motor 95. Then, the display control unit 914 reads out a warning message from the warning message storage unit 921 for notifying the user that a foreign object has entered the paper feeding unit 19 and displays the warning message on the display unit 9 (step S22).

  Further, if the stop position of the lift plate 61 is different from the position stored in the lift plate position storage unit 911 (step S21; NO), that is, if the lift plate 61 stops at a position different from the first time and this time, an abnormality The determination unit 913 determines that the motor 95 has failed, and the control unit 91 stops the motor 95. Then, the display control unit 914 reads a warning message for notifying the user of the failure of the motor 95 from the warning message storage unit 921 and displays the warning message on the display unit 9 (step S23).

  On the other hand, when the elevating plate 61 does not stop (step S20; NO), and the upper surface of the sheet bundle S reaches the sheet feeding position (step S24; YES), the control unit 91 determines that the sheet bundle S is normally fed to the sheet feeding position. Therefore, the motor 95 is stopped (step S25), and the process is terminated. When the upper surface of the sheet bundle S does not reach the sheet feeding position (step S24; NO), the control unit 91 shifts the process to step S20.

  As described above, when the amount of change of the elevating plate 61 per predetermined time is less than the reference value, the motor 95 is stopped and the warning message prompting the user to confirm the inside of the paper feeding unit 19 is displayed on the display unit 9. Is displayed, it is possible to detect an abnormality in the paper feeding unit 19 even when the elevating plate 61 continues to rise, and to further improve the detection accuracy of foreign matter contamination.

1 Image forming device 19 Paper feed unit (paper feed device)
39 Upper limit detection sensor (upper limit detection means)
51 Remaining amount detection sensor (position measuring means)
6 Input operation unit 9 Display unit 91 Control unit (drive control means)
911 Lift plate position storage unit (position storage means)
912 Position comparison unit (comparison means)
913 Abnormality determination unit (determination means)
914 Display control unit (display control means)
915 Change amount calculation unit (calculation means)
92 storage unit 921 warning message storage unit (warning message storage means)
922 Reference value storage unit 93 Image memory 94 Image processing unit 95 Motor (drive means)
96 Network I / F section

Claims (8)

A paper feeding device that feeds a recording medium stored in a recording medium storage unit to the outside,
Conveying means for feeding the recording medium one by one to the outside;
Lifting and lowering means for lifting the recording medium to a position in contact with the conveying means;
Drive means for lifting the elevating means;
Drive control means for performing drive control of the drive means;
Upper limit detection means for detecting whether or not the recording medium is in a position where it comes into contact with the transport means;
Position measuring means for detecting the position of the lifting means in the lifting direction; and
The position of the elevating means detected by the position measuring means from the start of ascent of the elevating means by the driving means until the upper limit detecting means detects that the recording medium is in a position in contact with the conveying means. Position storage means for storing at predetermined time intervals;
Comparing means for comparing the position of the lifting means at the time of detection detected by the position measuring means with the position of the lifting means measured by the position measuring means last time stored in the position storage means;
Determining means for determining that an abnormality has occurred in the sheet feeding device when the position of the lifting means at the time of detection coincides with the position of the previous lifting means stored in the position storage means;
Display control means for controlling display of the display unit;
And the drive control unit stops driving of the drive unit when the determination unit determines that an abnormality has occurred.   After the determination unit determines that an abnormality has occurred in the sheet feeding device and the drive control unit stops driving the drive unit, the position storage unit stores the position of the elevating unit, and then The drive control means drives the drive means to raise the elevating means once to the initial position and then raises the elevating means again. From the start of the elevating of the elevating means by the drive means, the upper limit detecting means detects that the recording medium is If the elevating means stops at the same position as the position stored in the position storage means until it is detected that the position is in contact with the conveying means, the determination means will cause a foreign object in the paper feeding device. The sheet feeding device according to claim 1, wherein the sheet feeding device is determined to be mixed.   Warning message storage means for storing a warning message according to the type of abnormality of the paper feeding device is further provided, and when the judgment means judges that foreign matter is mixed in the paper feeding device, the display control means 3. The paper feeding device according to claim 2, wherein a warning message indicating that foreign matter is mixed in the paper feeding device is read from the warning message storage means and displayed on the display unit.   After the determination unit determines that an abnormality has occurred in the sheet feeding device and the drive control unit stops driving the drive unit, the position storage unit stores the position of the elevating unit, and then The drive control means drives the drive means to raise the elevating means once to the initial position and then raises the elevating means again. From the start of the elevating of the elevating means by the drive means, the upper limit detecting means detects that the recording medium is If the elevating means stops at a position different from the position stored in the position storage means until it is detected that the position is in contact with the conveying means, the determination means indicates that the drive means has failed. 3. The sheet feeding device according to claim 1, wherein the driving control unit stops driving of the driving unit.   Warning message storage means for storing a warning message according to the type of abnormality of the paper feeding device is further provided, and when the determination means determines that the drive means is out of order, the display control means The sheet feeding device according to claim 4, wherein a warning message indicating that the driving unit is out of order is read from a storage unit and displayed on the display unit.   When the comparison means determines that the current position of the lifting means and the previous position of the lifting means stored in the position storage means do not match, the current position of the lifting means and the position storage means are stored. And calculating means for calculating a change amount per unit time of the position of the elevating means from the previous difference in position of the elevating means, wherein the determining means is a predetermined change amount. The sheet feeding device according to any one of claims 1 to 5, wherein the sheet feeding device is configured to determine whether or not it is smaller.   When the determination means determines that the calculated change amount is smaller than a predetermined change amount, the display control means may indicate that an abnormality has occurred in the sheet feeder from the warning message storage means. The sheet feeding device according to claim 6, wherein a warning message indicating the above is read and displayed on the display unit. A paper feeding device according to any one of claims 1 to 7,
Image forming means for forming an image on a recording medium fed by the paper feeding device;
An image forming apparatus.

Images