JP2008024465A - Paper feeding device, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeding device, in which recording paper is supplied from above as an upper cover is opened, capable of informing that recording paper has been excessively supplied, and an image forming device using the paper feeding device. <P>SOLUTION: In a case where an opening/closing detection switch 102 detects that a cover member 16 is closed, as an upper surface detection sensor 104 detects that the position of the uppermost surface of the recording paper is above a feed position where the recording paper can be fed by a feed roller 351, then a paper base 20 is lowered by a lift drive part 110. In a case where a lower limit detection switch 103 detects that the paper base 20 is lowered to a lower limit position before the upper surface detection sensor 104 detects that the position of the uppermost surface of the recording paper is below the feed position, a buzzer 105 alarms overloading of the recording paper. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a paper feeding device used in an image forming apparatus such as a copying machine, and more particularly to a paper feeding device on which a large-capacity recording paper can be mounted, and further to an image forming apparatus provided with the paper feeding device.

  2. Description of the Related Art Conventionally, for example, as a paper feeding device in an image forming apparatus such as a multifunction machine that integrates a scanner function, a facsimile function, a printer function, and a copy function, it is additionally installed on the side of the main body of the image forming apparatus and has a large capacity, that is, 1,000 There are known ones capable of loading a sheet of recording paper or more. This type of paper feeder has a tray that loads and moves up and down with a large amount of recording paper inside the main body of the paper feeder, a lift motor that drives the tray up and down, and a topmost recording paper that is mounted on the tray. A sheet feeding roller fixedly provided on the upper part of the sheet feeding apparatus main body for feeding one sheet at a time and transporting it to the recording section in the image forming apparatus, and a sheet feeding apparatus body for the user to replenish recording paper When the door provided on the side surface of the unit is opened, the tray is lowered to the lowest point so that the recording paper can be easily replenished (see, for example, Patent Document 1).

  In addition, when a user replenishes recording paper, the upper cover of the main body of the paper feeding device is opened and the recording paper is stacked and replenished on the paper stand from above. Some of them are In this way, in the case of a paper feeding device that opens the top cover and replenishes recording paper from above, it is the same as that that opens the door provided on the side as described above and replenishes recording paper from the side. Thus, if the tray is lowered to the lowest point when the upper cover is opened, the user must place the recording paper in a low position in such a posture as to look into the paper feeder main body from above. This is inconvenient.

  Therefore, in a paper feeder that opens the top cover and replenishes recording paper from above, even if the user opens the top cover, the user can keep the tray at a high position without lowering it, or the user can replenish it at once. It is known that the tray is slightly lowered by the thickness of the recording paper bundle, which is about the thickness of one pack of commercially available supplementary paper bundles. Further, in the paper feeding device configured to replenish the recording paper from above, when the upper cover is opened so that the paper feeding roller does not get in the way when the recording paper is replenished, the paper feeding roller is placed in the tray. Retreat from above.

  By the way, as described above, in the paper feeding device in which the upper cover is opened and the recording paper is replenished from above, the paper supply device fixedly provided on the upper side of the recording paper is similar to the one that replenishes the recording paper from the side. When there is no paper roller or paper feeder ceiling, and the top cover is opened, the paper feed roller is retracted from the top of the recording paper and there are no obstacles at the top of the tray. Can do. However, even in a paper feeding device that opens the top cover and replenishes recording paper, if recording paper is stacked beyond the capacity of the paper feeding device, the paper feed roller lowers the tray to the lowest point after replenishing the recording paper Even when trying to return the paper to the paper feed position, the uppermost surface of the recording paper exceeds the paper feed position of the paper feed roller, resulting in overloading and paper feed failure.

Therefore, conventionally, a mark indicating the upper limit position where the recording paper can be stacked on the tray is attached to the main body of the paper feeding apparatus, and it is described in the instruction manual or the paper feeding so as not to replenish the recording paper beyond this mark. The user is alerted by attaching a caution label to the apparatus main body.
Japanese Patent Laid-Open No. 7-239639

  However, if the user does not read the instruction manual, forgets the precautions regarding the replenishment amount of the recording paper, or the user overlooks the mark at the upper limit position, or the mark is hidden by the refilled paper. In such a case, the user replenishes the recording paper beyond the mark of the upper limit position, and there is a disadvantage that a paper feeding failure occurs.

  The present invention has been made in view of such circumstances, and in a paper feeding device in which the upper cover is opened and the recording paper is supplied from above, the user is notified that the recording paper has been supplied excessively. It is an object of the present invention to provide a sheet feeding device capable of informing the user and an image forming apparatus using such a sheet feeding device.

  A sheet feeding device according to the present invention includes a box-shaped housing having an upper opening for accommodating stacked recording sheets, an openable / closable lid that covers the opening of the housing, A paper feeding unit that is disposed above and feeds the recording paper, and retracts from a feeding position where the recording paper can be fed when the lid is opened, and detects the opening and closing of the lid An open / close detection unit that is disposed in the casing, and is capable of moving up and down to mount the stacked recording paper, a lift driving unit that drives the paper base to move up and down, and a recording paper stacked on the paper base An upper surface detection unit for detecting the position of the uppermost surface, a lower limit detection unit for detecting that the paper table has been lowered to the lower limit position, a notification unit for reporting overloading of the recording paper, and the open / close detection That the lid is closed and the upper surface detector If the position of the uppermost surface is detected to be equal to or higher than the paper feed position at which the recording paper can be fed by the paper feed unit, the paper platform is lowered by the lift drive unit, The notification unit when the lower limit detection unit detects that the paper table has been lowered to the lower limit position before the upper surface detection unit detects that the position of the uppermost surface is below the paper feed position. And a control unit for notifying overloading of the recording paper.

  According to this structure, the lid | cover body which can be opened and closed is provided in the box-shaped housing | casing by which upper part was opened. Further, the feeding unit disposed above the housing is configured to retreat from a feeding position where the recording paper can be fed when the lid is opened. Then, it is detected that the lid has been closed by the open / close detection unit, and the uppermost position of the recording paper stacked on the paper table by the upper surface detection unit is a paper feed unit that can feed the recording paper by the paper feed unit. When it is detected that the position is equal to or greater than the position, the control unit detects that the paper table is lowered by the elevating drive unit, and the upper surface detection unit detects that the position of the uppermost surface of the recording paper is below the paper feed position. When the lower limit detection unit detects that the paper table has been lowered to the lower limit position before, the overloading of the recording paper can be detected and notified by the notification unit.

  An image forming apparatus according to the present invention includes the above-described paper feeding device and an image forming unit that forms an image on a recording sheet fed from the paper feeding device. According to this configuration, in the image forming apparatus including the supply device that supplies the recording paper used for image formation, it is possible to notify overloading of the recording paper in the supply device.

  Further, the notification unit in the paper feeding device outputs an overloading signal indicating the overloading of the recording paper, and when the overloading signal is received, the recording paper is overloaded. It is preferable to further include a display unit that displays a message indicating. According to this configuration, since the overloading of the recording paper in the supply device can be displayed on the display unit provided in the image forming apparatus, the overloading can be easily notified to the user.

  In the sheet feeding device and the image forming apparatus having such a configuration, an overloading of the recording sheet is detected and notified by the notification unit in the sheet feeding device which is configured to replenish the recording sheet from above by opening the lid. Therefore, convenience can be improved.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted. FIG. 1 is a side view schematically showing an internal configuration of an image forming apparatus including a sheet feeding device according to an embodiment of the present invention. This image forming apparatus is configured as a multifunction machine 1 having multiple functions such as a scanner function, a copy function, a printer function, and a facsimile function. Note that the image forming apparatus is not limited to a multifunction peripheral, and may be an image forming apparatus such as a copying machine, a printer apparatus, or a facsimile apparatus.

  The multifunction machine 1 includes an apparatus main body 2, a stack tray 3 disposed on the left side of the apparatus main body 2, a document reading unit 5 disposed on the upper part of the device main body 2, and a document reading unit 5. A document feeding unit 6 disposed above and a sheet feeding device 10 disposed on the right side of the apparatus main body 2 and capable of accommodating a large capacity recording sheet are provided. The paper feeding device 10 is detachably attached as an optional device.

  An operation unit 47 is provided at the front part of the multifunction machine 1. The operation unit 47 displays a start key 471 for a user to input a print execution instruction, a ten key 472 for inputting the number of copies to be printed, operation guide information for various copying operations, and the like. A display unit 473 formed of a liquid crystal display or the like having a touch panel function, a reset key 474 for resetting setting contents set in the display unit 473, and a stop key for stopping a printing (image forming) operation being executed And a function switching key 477 for switching between a copy function, a printer function, a scanner function, and a facsimile function.

  A display unit 473 having a touch panel function also allows the user to select a recording sheet. That is, the user can select a desired one of a plurality of types of recording paper displayed as a button on the display unit 473 as a button by touching it with a finger. The plural types of recording paper include those mounted on the paper feeding device 10. Since a large number of recording sheets mounted on the sheet feeding device 10 are recording sheets frequently used by the user, it is preferable to display them as default options on the display unit 473.

  The document reading unit 5 includes a scanner unit 51 including a CCD (Charge Coupled Device) sensor and an exposure lamp, and a document table 52 and a document reading slit 53 made of a transparent member such as glass. The scanner unit 51 is configured to be movable by a driving unit (not shown). When reading a document placed on the document table 52, the scanner unit 51 moves along the document surface at a position facing the document table 52, and reads the document image. Image data acquired while scanning is output to the main body control unit 201. When reading a document fed by the document feeding unit 6, the document moves to a position facing the document reading slit 53, and synchronizes with the document feeding operation by the document feeding unit 6 via the document reading slit 53. The image of the original is acquired, and the image data is output to the main body control unit 201.

  The document feeding unit 6 includes a document placing unit 61 for placing a document, a document discharge unit 62 for discharging a document whose image has been read, and a document placed on the document placing unit 61. A document transport mechanism 63 including a paper feed roller (not shown), a transport roller (not shown), and the like for feeding the paper one by one to a position facing the document reading slit 53 and discharging it to the document discharge section 62 is provided. The document conveying mechanism 63 further includes a re-conveying paper reversing mechanism (not shown) that reverses the document upside down to a position facing the document reading slit 53, and scans both sides of the document through the document reading slit 53. Can be read from.

  Further, the document feeding unit 6 is provided so as to be rotatable with respect to the apparatus main body unit 2 so that the front side thereof can move upward. By moving the front side of the document feeder 6 upward to open the upper surface of the document table 52, the operator can place a read document, for example, a book in a spread state, on the upper surface of the document table 52. It has become.

  The apparatus main body 2 is fed from a plurality of paper feed cassettes 461, a paper feed roller 462 that feeds recording sheets from the paper feed cassette 461 one by one and transports them to the image forming unit 40, and a paper feed device 10. Operation of the conveyance path 465 for conveying the recording paper to the image forming section 40, the image forming section 40 for forming an image on the recording paper conveyed from the conveyance path 465 and the paper feed roller 462, and the operation of each section in the apparatus main body section 2 For example, a main body control unit 201 configured using a microcomputer.

  The image forming unit 40 outputs an optical unit 42 based on the image data acquired by the scanner unit 51 to expose the photosensitive drum 43, and a developing unit 44 that forms a toner image on the photosensitive drum 43. A transfer unit 41 for transferring the toner image on the photosensitive drum 43 to the recording paper, a fixing unit 45 for fixing the toner image to the recording paper by heating the recording paper to which the toner image has been transferred, and an image forming unit 40. And provided with conveying rollers 463, 464, etc., which are provided in the inner sheet conveying path and convey the recording sheet to the stack tray 3 or the discharge tray 48.

  When forming images on both sides of the recording paper, the image forming unit 40 forms an image on one side of the recording paper, and then the recording paper is nipped by the conveyance roller 463 on the discharge tray 48 side. To do. In this state, the conveyance roller 463 is reversed to switch back the recording paper, and the recording paper is sent to the paper conveyance path L and conveyed again to the upstream area of the image forming unit 40, and an image is formed on the other surface by the image forming unit 40. After the formation, the recording paper is discharged to the stack tray 3 or the discharge tray 48.

  FIG. 2 is a side view schematically showing the configuration of the sheet feeding device in the image forming apparatus according to the embodiment of the present invention. The paper feeding device 10 includes a housing 11, a paper base 20 on which the stacked recording papers are mounted, a vertical driving unit 110 that drives the paper base 20 up and down, drive control of the vertical driving unit 110, A connector 101 (notification unit) that is connected to the control unit 100 that detects stacking and the apparatus main body unit 2 and outputs an overloading signal indicating the overloading of recording paper output from the control unit 100 to the main body control unit 201; The paper feed unit 35 that feeds the recording paper and conveys it to the image forming unit 40 of the multifunction device 1, the open / close detection switch 102 (open / close detection unit) that detects the open / closed state of the lid 16, and the paper base 20 has been lowered to the lower limit position. , A lower limit detection switch 103 (lower limit detection unit), and a buzzer 105 (notification unit) that emits a warning sound indicating overloading of recording paper. A broken line X indicates an upper limit position where the recording paper can be replenished.

  The casing 11 is formed in a substantially rectangular box shape with an upper opening, and a lid 16 is attached to close the upper opening so that the opening can be opened and closed. Further, a discharge port 12 for discharging the recording paper fed by the paper feeding unit 35 to the apparatus main body 2 and a connector 101 are provided on the side wall of the housing 11 on the side facing the apparatus main body 2. ing.

  The lid 16 is rotatably supported by a hinge (not shown) in the vicinity of the upper end of the side wall of the housing 11 on the side facing the apparatus main body 2. The open / close detection switch 102 is attached in the vicinity of the upper end of the side wall of the casing 11 on the side opposite to the apparatus main body 2. When the lid 16 is closed, the open / close detection switch 102 is pressed and turned on, and the lid 16 is opened. The open / close detection switch 102 is turned off.

  The paper base 20 is a substantially plate-like member, is supported substantially horizontally by the elevating drive unit, and can be moved up and down by the elevating drive unit 110. For example, the elevating drive unit 110 converts an endless belt (not shown) spanned between a pair of belt gears (not shown) spaced apart in the vertical direction into a control signal from the control unit 100 by a motor (not shown). By driving accordingly, the paper table 20 connected to a predetermined part of the endless belt is raised and lowered.

  The lower limit detection switch 103 is attached to the lower limit position of the movable range of the paper table 20, and is turned on when the paper table 20 reaches the lower limit position.

  The paper feed unit 35 includes a paper feed roller 351, a support member 352, a pair of transport rollers 353, a transport path 354, a frame 355, a rotating shaft 356, and a connecting rod 357. A paper feed roller 351 is attached to substantially the front end of the support member 352, and the other end of the support member 352 is attached to the frame 355 by a rotation shaft 356 so as to be rotatable. Further, the substantially central portion of the support member 352 is connected to the lid body 16 by a connecting rod 357.

  As a result, when the lid 16 is opened, the support member 352 is interlocked and lifted by the connecting rod 357, the support member 352 is rotated, and the paper feed roller 351 is retracted from the recording paper feeding position. Further, when the lid 16 is closed, the support member 352 is interlocked and pushed down by the connecting rod 357 so that the paper feed roller 351 is disposed at the feeding position. The paper feed roller 351 disposed at the feeding position feeds the uppermost recording paper mounted on the paper tray 20 one by one and feeds it to the pair of transport rollers 353.

  A conveyance path 354 is provided between the conveyance roller 353 and the discharge port 12. The recording paper fed from the paper feed roller 351 is fed by the transport roller 353 to the transport path 465 of the apparatus main body 2 via the transport path 354 and the discharge port 12.

  3 is an enlarged perspective view of a portion surrounded by a broken line A in FIG. As shown in FIG. 3, the connecting rod 357 includes a pair of left and right connecting rods 357a and a connecting rod 357b. The support member 352 includes an arm 358 and a holding plate 359. For example, both ends of the plate-like member in a predetermined direction are bent at substantially right angles in the same direction, and the arm 358 is formed into a U-shape including a base portion 582 of the plate-like member and bent portions 583 and 584 at both ends of the base portion 582. ing. The paper feed roller 351 is fitted between the bent portions 583 and 584, and the rotation shaft 581 of the paper feed roller 351 is attached so as to penetrate the vicinity of one end of the bent portions 583 and 584. Further, the rotating shaft 356 passes through the bent portions 583 and 584 in the vicinity of the other ends of the bent portions 583 and 584. Thus, the arm 358 is rotatable about the rotation shaft 356.

  Further, the arm 358 is provided with a light shielding plate 582 configured such that, for example, a part of the base portion 582 is extended in a direction parallel to the rotation shaft 356 and a tip portion thereof is bent in the same direction as the bent portions 583 and 584. It has been.

  Then, with the opening side of the U-shape of the arm 358 combined so as to fit between the bent portions 592 and 593 of the holding plate 359, the rotating shaft 356 passes through the bent portions 592 and 593. Yes. Thereby, the holding plate 359 is rotatable about the rotation shaft 356. The base 591 is provided with a notch 594 formed so that the paper feed roller 351 fits therein.

  The connecting rods 357a and 357b are respectively provided with long holes 571a and 571b in the vicinity of the end on the support member 352 side. An engaging member 595 that engages with the elongated hole 571a is provided in the bent portion 592, and an engaging member 596 that engages with the elongated hole 571b is provided in the bent portion 593. The long holes 571a and 571b and the engaging members 595 and 596 are slidable. If the base 591 is not in contact with the recording paper, the engaging members 595 and 596 are pushed down by the weight of the support member 352 and engaged at the lower ends of the long holes 571a and 571b.

  Thus, when the lid body 16 is closed, the connecting rods 357a and 357b are pushed down, and the holding plate 359 is pushed down with the engaging members 595 and 596 engaged with the lower ends of the long holes 571a and 571b. The arm 358 comes into contact with the holding plate 359 so that the weight of the arm 358 and the paper feed roller 351 is supported. When the holding plate 359 is pushed down by the connecting rod 357, the arm 358 and the paper feed roller 351 are supported. Is lowered together with the holding plate 359 to become a paper feeding position. At this time, the paper feed roller 351 protrudes downward from the notch 594.

  Since the arm 358 and the paper feed roller 351 are supported by the arm 358 coming into contact with the holding plate 359 where the arm 358 is going to be lowered by its own weight, the paper feed roller 351 protrudes downward from the notch 594. However, the arm 358 is lifted in conjunction with the paper feed roller 351 so as to be separated from the holding plate 359 when the recording paper stacked on the paper base 20 is pushed up.

  An upper surface detection sensor (upper surface detection unit) 104 is attached to the surface of the base 591 on the arm 358 side. As the upper surface detection sensor 104, for example, a so-called photo interrupter is used. The upper surface detection sensor 104 includes a light emitting unit 104a and a light receiving unit 104b that face each other at a predetermined interval. Then, with the arm 358 and the holding plate 359 in contact with each other, the light shielding plate 582 of the arm 358 enters between the light emitting unit 104a and the light receiving unit 104b, and the light from the light emitting unit 104a to the light receiving unit 104b is shielded. The upper surface detection sensor 104 is turned off. The state in which the arm 358 and the holding plate 359 are in contact is nothing other than the state in which the paper feed roller 351 is not lifted by the recording paper stacked on the paper base 20.

  Therefore, the upper surface detection sensor 104 is turned off when the uppermost surface of the recording paper stacked on the paper table 20 has not reached the height at which the recording paper contacts the paper feed roller 351.

  On the other hand, when the paper feed roller 351 located at the paper feed position is pushed up against the recording paper stacked on the paper base 20, the arm 358 is lifted in conjunction with the paper feed roller 351, and the light shielding plate 582 of the arm 358. Is removed from between the light emitting unit 104a and the light receiving unit 104b, so that light reaches the light receiving unit 104b from the light emitting unit 104a and the upper surface detection sensor 104 is turned on.

  Accordingly, the upper surface detection sensor 104 is turned on when the uppermost surface of the recording paper stacked on the paper table 20 reaches a height at which the uppermost surface of the recording paper contacts the paper feed roller 351 at the paper feed position. In this way, the upper surface detection sensor 104 detects the position of the uppermost surface of the recording paper stacked on the paper table 20.

  Further, when the position of the uppermost surface of the recording paper stacked on the paper table 20 is further above the paper feeding position, the base 591 is pushed up by the recording paper, and the upper surface detection sensor 104 is turned on. The engaging members 595 and 596 slide in the long holes 571a and 571b. That is, the upper surface detection sensor 104 is turned on when the position of the uppermost surface of the recording paper stacked on the paper table 20 is equal to or higher than the paper feeding position.

  The control unit 100 includes, for example, a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a nonvolatile ROM (Read Only Memory) that stores a predetermined control program, and a RAM (Random) that temporarily stores data. Access Memory) and its peripheral circuits and the like.

  Then, the control unit 100 executes the control program stored in the ROM to detect that the open / close detection switch 102 is turned on and the lid body 16 is closed, and the upper surface detection sensor 104 is turned on and recorded. When it is detected that the position of the uppermost surface of the paper is equal to or higher than the paper feed position, the lifting / lowering drive unit 110 lowers the paper table 20, and the upper surface detection sensor 104 is turned off to determine the position of the uppermost surface of the recording paper. If it is detected that the lower limit detection switch 103 is turned on and the paper base 20 is lowered to the lower limit position before it is detected that it is below the paper feed position, the buzzer 105 is sounded or the recording paper is overloaded. Is output to the main body control unit 201 via the connector 101.

  The control unit 100 is not limited to the example provided in the sheet feeding device 10, and for example, the main body control unit 201 provided in the apparatus main body unit 2 may function as the control unit 100. Further, instead of the buzzer 105, a display device such as an LED (Light Emitting Diode) may be used as the notification unit.

  Further, when receiving an overloading signal indicating recording paper overloading from the control unit 100, the main body control unit 201 causes the display unit 473 to display a message indicating that recording paper overloading has occurred.

  Next, the operation of the sheet feeding device 10 configured as described above will be described. FIG. 4 is a flowchart illustrating an example of the operation of the sheet feeding device 10. First, when the user lifts and opens the lid 16 to replenish the recording paper in the paper feeder 10, the open / close detection switch 102 is turned off, and the rotating shaft 356 is interlocked with the lid 16 by the connecting rod 357. The support member 352 is rotated about the shaft, and the paper feed roller 351 is retracted from the feeding position where the recording paper can be fed, that is, the position above the paper table 20. As a result, the support member 352 and the paper feed roller 351 are retracted to a position that does not interfere with the supply of the recording paper from above.

  When the lid 16 is opened and the open / close detection switch 102 is turned off (YES in step S1), the paper table 20 is replenished by the user at a time by the elevating drive unit 110 in accordance with a control signal from the control unit 100. The thickness of the recording paper bundle is lowered, for example, about the thickness of one commercially available supplementary paper bundle, for example, 5 cm (step S2). Thereby, a space for accommodating new recording paper is secured.

  Note that the control unit 100 may lower the paper table 20 by the elevation drive unit 110 by 5 cm each time the user presses an operation button (not shown), for example. As a result, when the user intends to replenish a plurality of packs of a bundle of sheets, the user can press down an operation button (not shown) to lower the sheet table 20 as much as necessary.

  As described above, in the paper feeding device 10, even when the lid 16 is opened, the paper base 20 is not lowered to the lowest point, and the uppermost surface of the recording paper is maintained at a relatively high position. When replenishing the paper, there is no need to place the recording paper at a low position in such a posture that the paper feeding device 10 is looked down from above, and the convenience when replenishing the recording paper is improved.

  Next, when the user closes the cover body 16 after replenishing the recording paper, the open / close detection switch 102 is turned on, and the support member 352 rotates around the rotation shaft 356 in conjunction with the cover body 16 by the connecting rod 357. The paper feed roller 351 is moved and disposed at a feeding position above the paper table 20 where the recording paper can be fed.

  FIG. 5 is an explanatory diagram for explaining a state of the paper feeding device when the user finishes the replenishment of the recording paper P and closes the lid 16. In FIG. 5, the uppermost surface of the recording paper P replenished by the user is within the broken line X, which is the upper limit position where the recording paper P can be replenished, and the recording paper P is properly replenished without being overloaded. Show.

  Then, it is detected by the control unit 100 that the open / close detection switch 102 is turned on (YES in step S3), it is determined that the user has finished the replenishment operation of the recording paper P, and the upper surface detection sensor is further detected by the control unit 100. It is confirmed whether or not 104 is turned on (step S4). In the state shown in FIG. 5, the recording paper P is not overloaded, the uppermost surface of the recording paper P is below the broken line X, and is not in contact with the paper feed roller 351. OFF (NO in step S4).

  Then, the raising / lowering drive unit 110 is set in accordance with a control signal from the control unit 100 so that the uppermost surface of the recording paper P is brought into contact with the paper feed roller 351 so that the recording paper P can be fed to the apparatus main body unit 2. As a result, the paper table 20 is raised (step S5). Then, as shown in FIG. 6, when the top surface of the recording paper P comes into contact with the paper feed roller 351 and the upper surface detection sensor 104 is turned on (YES in step S6), the recording paper P is fed to the apparatus main body 2. Since it is possible, the control unit 100 enters a standby state and finishes the process until the recording paper P is fed along with the image forming operation by the apparatus main body unit 2.

  On the other hand, when the user finishes replenishing the recording paper P and closes the cover 16, the uppermost surface of the recording paper P exceeds the broken line X as shown in FIG. When the paper feed roller 351 is in contact with the recording paper P with the paper feed roller 351 lifted above the paper feed position, the upper surface detection sensor 104 is turned on in step S4 (YES in step S4).

  However, in the paper feeding device 10, in order to improve the convenience when replenishing the recording paper as described above, the paper base 20 is not lowered to the lower limit position. It cannot be determined whether or not the recording paper P is overloaded. Therefore, in order to determine whether or not the recording paper P is overloaded, the paper platform 20 is lowered by the elevation drive unit 110 in accordance with a control signal from the control unit 100 (step S7).

  When the uppermost surface of the recording paper P moves away from the paper feed roller 351 and the upper surface detection sensor 104 is turned off (YES in step S8), it is determined that the recording paper P is not overloaded, and steps S5 and S6 are performed as described above. By this process, the recording paper P is brought into contact with the paper feed roller 351 at the paper feeding position, that is, the recording paper P can be fed to the apparatus main body 2 and the processing is ended.

  On the other hand, in step S8, as shown in FIG. 8, the uppermost surface of the recording paper P is not separated from the paper feed roller 351, and therefore the upper surface detection sensor 104 is not turned off (NO in step S8). When the lower limit detection switch 103 is turned on and the lower limit detection switch 103 is turned on (YES in step S9), the control unit 100 determines that the recording paper P is overloaded, and the buzzer 105 is activated in response to a control signal from the control unit 100. The user is notified of the overloading of the recording paper P by the warning sound (step S10).

  Next, an overload signal indicating an overload of recording paper is transmitted from the control unit 100 to the main body control unit 201 via the connector 101 (step S11). Then, the main body control unit 201 displays a message indicating that the recording paper is overloaded on the display unit 473.

  As described above, in the paper feeding device in which the upper cover is opened and the recording paper is replenished from above by the processing in steps S1 to S11, the lid 16 is opened to improve the convenience when the recording paper is replenished. Even when the upper surface of the recording paper P is kept at a relatively high position without lowering the paper base 20 to the lower limit position, the paper base 20 is lowered and the upper surface detection sensor 104 is turned off. By detecting that the lower limit detection switch 103 is turned on before detection, an overload of recording paper is detected, a warning sound is generated by the buzzer 105, and a message is displayed on the display unit 473 of the apparatus main body unit 2. Thus, it is possible to notify the user that the recording paper has been replenished excessively.

1 is a side view schematically showing an internal configuration of an image forming apparatus including a sheet feeding device according to an embodiment of the present invention. FIG. 2 is a side view schematically illustrating a configuration of a sheet feeding device in the image forming apparatus illustrated in FIG. 1. FIG. 3 is an enlarged perspective view of a portion surrounded by a broken line A in FIG. 2. 3 is a flowchart illustrating an example of an operation of the sheet feeding device illustrated in FIG. 2. FIG. 3 is an explanatory diagram for explaining an operation of the sheet feeding device illustrated in FIG. 2. FIG. 3 is an explanatory diagram for explaining an operation of the sheet feeding device illustrated in FIG. 2. FIG. 3 is an explanatory diagram for explaining an operation of the sheet feeding device illustrated in FIG. 2. FIG. 3 is an explanatory diagram for explaining an operation of the sheet feeding device illustrated in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multifunction device 2 Apparatus main body part 10 Paper feed apparatus 11 Housing | casing 12 Discharge port 16 Cover body 20 Paper stand 35 Paper feed part 40 Image formation part 100 Control part 101 Connector 102 Opening / closing detection switch 103 Lower limit detection switch 104 Upper surface detection sensor 105 Buzzer DESCRIPTION OF SYMBOLS 110 Lift drive part 201 Main body control part 351 Paper feed roller 352 Support member 353 Conveyance roller 354 Conveyance path 355 Frame 356 Rotating shaft 357, 357a, 357b Connecting rod 358 Arm 359 Holding plate 473 Display part

Claims (3)

A box-shaped housing with an open top for accommodating laminated recording paper;
An openable / closable lid that covers the opening of the housing;
A paper feeding unit that is disposed above the housing and feeds the recording paper, and retracts from a feeding position where the recording paper can be fed when the lid is opened;
An opening / closing detection unit for detecting opening / closing of the lid;
A paper table which is disposed in the housing and can be moved up and down to mount the laminated recording paper;
An elevating drive unit for elevating and driving the paper table;
An upper surface detection unit for detecting the position of the uppermost surface of the recording paper stacked on the paper table;
A lower limit detecting unit for detecting that the paper table has been lowered to the lower limit position;
An informing unit for informing overloading of the recording paper;
It is detected that the lid is closed by the open / close detection unit, and the position of the uppermost surface is equal to or higher than a paper feed position where the recording paper can be fed by the paper feed unit by the upper surface detection unit. Is detected, the lower limit is detected before the upper surface detecting unit detects that the position of the uppermost surface is lower than the paper feeding position after the paper table is lowered by the elevating drive unit. And a control unit that causes the notification unit to notify the overloading of the recording paper when the unit detects that the sheet base has been lowered to the lower limit position. A sheet feeding device according to claim 1;
An image forming apparatus comprising: an image forming unit configured to form an image on the recording paper fed from the paper feeding device. The notification unit in the paper feeding device outputs an overloading signal indicating overloading of the recording paper,
An image forming apparatus, further comprising: a display unit that displays a message indicating that the recording paper is overloaded when the overloading signal is received.

Images