JP2004262606A - Sheet feeder and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely detect a jam when paper is transferred and prevent damage of an apparatus in a sheet feeder capable of feeding the paper by arranging first and second paper housing portions nearly horizontally and in parallel and transferring a paper bundle. <P>SOLUTION: When it is detected that the paper P1 of the first paper housing portion 11 is consumed, a bottom plate 16 is lowered, end fences 23, 24 are retreated, a back fence 32 is moved in a direction of the first paper housing portion 11 and a bundle of paper P2 is moved from the second paper housing portion 12 to the first paper housing portion 11. When the paper bundle is transferred without a jam, a paper bundle detection sensor 28 detects the end bottom arrival of the bundle of the paper P2 almost as soon as a forcing sensor 40 detects completion of transfer action of the back fence 32. When a buckling jam is generated, the paper bundle detection sensor 28 cannot detect an end bottom portion of the paper bundle even if the forcing sensor 40 detects the completion of transfer action of the back fence 32. In that case, the jam is indicated. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet feeder and an image forming apparatus using the same, such as a copying machine, a facsimile, and a printer.
[0002]
[Prior art]
Conventionally, a first sheet storage unit capable of stacking a plurality of sheets on a movable bottom plate, sheet feeding means for feeding sheets one by one from the first sheet storage unit, and substantially horizontally with the first sheet storage unit 2. Description of the Related Art There is known a paper feeder that includes a second paper storage unit that is arranged in parallel and is capable of stacking a plurality of paper sheets, and a unit that collectively transports the paper stacked in the second paper storage unit to the first paper storage unit. (For example, see Patent Document 1).
[0003]
This apparatus detects a jam when the sheets stacked in the second sheet storage unit are transferred to the first sheet storage unit at a time by detecting a position of a pressing plate for transferring the sheet and a home position sensor and a pressing plate detection sensor. When the load force that is caught during the transfer of a large number of paper bundles is larger than the rated torque of the motor, the rotation of the motor stops or becomes slow, and the signal of the pressure plate detection sensor becomes The jam is detected by disappearing or delaying.
[0004]
[Patent Document 1]
Patent No. 2831458 (Japanese Patent Laid-Open No. 04-179634)
[0005]
[Problems to be solved by the invention]
However, in the apparatus disclosed in Patent Document 1, when a jam occurs when the number of sheets stacked in the second sheet storage unit is small, the load force of the sheet jam during transfer is lower than the rated torque of the transfer motor, and Even if the sheet bundle has buckled and jammed, the movement of the pressing plate is completed, and the output of the pressing plate detection sensor cannot detect the jam, and the operation is switched to the next operation, that is, the operation of feeding paper. If the bottom plate of the first sheet storage unit is raised in a state where the sheet bundle is buckled, the bottom plate or the lifting mechanism may be damaged.
[0006]
An object of the present invention is to provide a paper feeder capable of accurately detecting a jam during paper transfer and preventing damage to the apparatus, and an image forming apparatus using the same, in view of the above conventional technology. .
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a sheet feeder according to claim 1 of the present invention has a movable bottom plate, and a first sheet storage portion capable of stacking a plurality of sheets on the bottom plate; A sheet feeding unit for feeding sheets one by one from the sheet storage unit, a second sheet storage unit arranged substantially horizontally and in parallel with the first sheet storage unit, and capable of stacking a plurality of sheets, A transfer unit for transferring the sheets stacked in the second sheet storage unit to the first sheet storage unit at a time, wherein at least one portion is provided on a movable bottom plate for stacking the sheets in the first sheet storage unit. Paper bundle detecting means for detecting the leading edge of the bottom portion of the sheet bundle to be transferred to the first sheet storage portion is provided at the bottom of the first sheet storage portion in correspondence with each of the at least one opening; Transporting the paper stored in the first paper storage section through the bottom plate; A bottom plate pressing means for biasing to the step side is provided, and the bias of the bottom plate pressing means can be released when the paper in the second paper storage section is transferred to the first paper storage section. I do.
[0008]
According to a second aspect of the present invention, in order to achieve the above object, in the paper feeder according to the first aspect, an opening provided in a movable bottom plate of the first paper storage portion is provided with the presence or absence of paper during a paper supply operation. And also serves as an opening for detecting the paper end for detecting the paper end.
[0009]
In order to achieve the above object, the image forming apparatus according to the third aspect uses the sheet feeding device according to the first or second aspect, and the sheet bundle detecting unit detects the sheet bundle based on the transfer start time of the sheet by the transfer unit. Means for counting the transfer time until the bottom end is detected, means for determining that the paper is being transported when the transfer time counted by the counting means exceeds a predetermined time, and determination output of the determination means. Accordingly, the transfer operation of the transfer means is stopped, and a display section jam message is displayed.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a schematic diagram of a copying machine to which the first embodiment of the present invention is applied. In the drawing, reference numeral 1 denotes a contact glass on which a document is placed, 2 denotes an optical system for irradiating the document and exposing the photoconductor 3, 4 denotes a charger, 5 denotes a developing device, 6 denotes a transfer / separator, 7 denotes a cleaning unit, Reference numeral 8 denotes a fixing unit, 9 denotes a pair of registration rollers, and 10 denotes a conventional tray for storing large-sized paper. In the figure, reference numeral 11 denotes a first paper storage unit, and reference numeral 12 denotes a second paper storage unit disposed horizontally and in parallel with the first paper storage unit 11.
[0011]
Further, in the drawing, L1 and L2 are guide rails for pulling out the upper tray 17, and 13 is a conventional tray 10 or a sheet P1 selected and fed from the first sheet storage unit 11 and fed to the registration roller pair 9. Transport means for transporting; 14, a manual paper feed section for paper; L3, L4, guide rails for guiding when pulling out the conventional tray 10; 15, paper feed means comprising a pickup roller, a feed roller, and a separation roller; Reference numeral 16 denotes a rotatable (liftable) bottom plate having one end engaged with the tray 17.
[0012]
Reference numeral 18 in the drawing denotes a pressure plate which is rotatable by a drive unit (not shown) fixed to the copying machine main body, and one end of which contacts the bottom plate 16 through a hole 17a of the tray. Reference numeral 19 denotes a limit switch for limiting the uppermost position of the uppermost sheet of the sheets P1 on the bottom plate 16, and reference numeral 20 denotes a descent detecting sensor for detecting that the pressure plate 18 has been lowered to a position where it does not contact the hole 17a of the tray.
[0013]
As described above, the conventional paper feed unit including the tray 10, the first paper storage unit 11, and the second paper storage unit 12 is of a two-stage paper feed type including an upper stage a and a lower stage b. An embodiment of the paper feeding device according to the present invention, that is, a conventional type in which a tray 17 capable of storing two bundles of half-size paper such as A4 is provided, and a large-size paper such as A3 is stored on the lower side b side. A tray 10 is provided, and both can be pulled out toward the front of the paper.
[0014]
In FIG. 1, the copying operation around the photoconductor 3 and the paper feeding operation from the lower stage b of the paper feeding unit are well-known, and thus the description is omitted, and the configuration and operation of the paper feeding from the upper stage a of the paper feeding unit will be described. FIG. 2 is a plan view showing the upper stage a of the sheet feeding unit, and FIG. 3 is a side view. A handle 17b is provided on the tray 17, and is used when the tray 17 is pulled out from the copying machine main body.
[0015]
The paper feeding means 15 provided at the front edge on the transport side of the tray 17 presses out the paper P1 loaded in the first paper storage unit 11 on the right side in the drawing and sends out the paper. A pair of side fences 21 and 22 for positioning the sheet P1 and a pair of back fences 23 and 24 and the sheet P1 that can be retracted from the sheet transfer zone, that is, the range in which the sheet P1 moves, are stacked in the first sheet storage unit 11. A bottom plate 16 is provided. The back fences 23 and 24 are configured to be operable as needed by a drive unit (not shown).
[0016]
Below the bottom plate 16, there is provided a lifting device which presses the bottom plate 16 and urges it toward the paper feeding means 15. The lifting device is constituted by a driving unit 26 including a forward / reverse rotation motor for driving the pressing shaft 25 to which the pressing plate 18 is fixed. When the pressing shaft 25 rotates clockwise in FIG. Then, the pressure plate 18 lifts the bottom plate 16 from below beyond the hole 17a opened in the tray 17, pushes and urges the paper P1 stacked on the tray 17 upward, and pushes the uppermost paper to the paper feed roller of the paper feeding means 15. Abut. The height of the uppermost sheet is controlled by controlling the ascent of the bottom plate 16 from a signal from a limit switch 19 for limiting the upper limit position so as to maintain the height at a constant height.
[0017]
In the drawing, reference numeral 27 denotes a paper end sensor for detecting the presence or absence of a sheet P1 in the first sheet storage unit 11. When there is no sheet P1 in the first sheet storage unit 11, the filler unit 27a of the paper end sensor 27 It is detected that there is no sheet P1 in the first sheet storage unit 11 by dropping into the opening 16a. When detecting that there is no sheet P1, the pressure shaft 25 is driven to rotate counterclockwise in FIG. The pressure shaft 25 is rotated counterclockwise until the pressure detection plate 20 detects that the pressure plate 18 has been lowered to a position where the pressure plate 18 does not contact the hole 17a of the tray.
[0018]
Further, a sheet bundle detection sensor 28 is disposed at the bottom of the tray 17 corresponding to the opening 16a of the bottom plate. The bottom plate 16 is located at the bottom of the tray 17 when there is no sheet in the first sheet storage unit 11, and at this time, the filler portion of the sheet bundle detection sensor 28 protrudes above the opening 16a of the bottom plate. In the left half of the tray 17 in the figure, a pair of side fences 29, 30, the bottom plate 31, and the substantially central portion of the sheet P2 for positioning the sheet P2 are pressed and transferred to the first sheet accommodating section 11 in a lump. A movable back fence 32 is provided.
[0019]
The back fence 32 is drivingly connected to a timing belt 33 stretched below the bottom plate 31 via a hole 31 a formed in the bottom plate 31. The timing belt 33 is stretched between the pulleys 34, 35, 36, and 37. The back fence 32 reciprocates by rotating the pulley 37 by a forward / reverse rotation motor 38 so as to freely rotate forward and backward. The positioning of the reciprocation is performed by detecting the projecting piece 32 a provided on the back fence 32 with the home sensor 39 and the push sensor 40.
[0020]
In the drawing, reference numeral 41 denotes a filler of a detection sensor for detecting the presence or absence of the paper P2 in the second paper storage unit 12, and the presence or absence of the paper P2 is detected by the filler 41 protruding from a small hole 31b formed in the bottom plate 31.
[0021]
Hereinafter, the control operation of the sheet feeding device will be described. When a start signal is input from the control device of the copying machine main body, the drive unit 26 raises the bottom plate 16. When the completion of the raising of the bottom plate 16 is detected by the detection of the limit switch 19, the driving unit 26 stops. Therefore, if the sheet P1 remains in the first sheet storage unit 11 according to the signal of the paper end sensor 27, the sheet feeding operation is started. The paper end sensor 27 detects that the paper P1 in the first paper storage unit 11 has been consumed and the first paper storage unit 11 has been emptied, and the paper P2 is present in the second paper storage unit 12. When this is detected by the filler 41, the drive unit 26 is driven to lower the bottom plate 16. When the lowering sensor 20 detects that the bottom plate 16 has been sufficiently lowered, the drive unit 26 stops, the end fences 23 and 24 are retracted from the paper transfer zone, and the forward / reverse rotation motor 38 is driven to move the back fence 32 to the first position. The sheet P2 is moved in the direction of the sheet storage unit 11 to move the bundle of sheets P2 from the second sheet storage unit 12 to the first sheet storage unit 11.
[0022]
When the transfer of the sheet bundle from the second sheet storage unit 12 to the first sheet storage unit 11 is normally performed without a jam, at substantially the same timing as when the push sensor 40 detects the completion of the transfer operation of the back fence 32. Then, the sheet bundle detection sensor 28 detects that the bundle of sheets P2 reaches the leading end bottom. At that time, the end fences 23 and 24 are moved to the sheet regulating position, the driving unit 26 is driven to raise the bottom plate 16, and the above-described sheet feeding operation is restarted.
[0023]
If the buckling jam occurs during the transfer of the bundle of sheets P2, the sheet bundle detection sensor 28 cannot detect the arrival of the bottom of the leading end of the sheet bundle even if the push sensor 40 detects the completion of the transfer operation of the back fence 32. In this case, the driving is immediately stopped, and at the same time, a jam is displayed on an operation unit (not shown) of the copying machine main body to prompt the user to perform the jam processing.
[0024]
As another case, even when the user mistakenly sets the size of the paper P2 to be put in the second paper storage unit 12 to a size smaller than the predetermined size, the push sensor 40 operates to move the back fence 32 in the same manner as described above. Even when the completion is detected, the sheet bundle detection sensor 28 cannot detect the arrival of the leading end bottom of the sheet bundle because the sheet is small. Also in this case, it is preferable to enter the jam processing flow.
[0025]
Conversely, when the user mistakenly sets the size of the paper P2 to be put in the second paper storage unit 12 to a size larger than the predetermined size, the push sensor 40 detects that the transfer of the back fence 32 has been completed. Since the sheet bundle detection sensor 28 detects the arrival at the bottom of the leading end of the sheet bundle, it is also preferable to enter the jam processing flow in this case. However, at the same time as displaying the jam on the operation unit of the copying machine main body, If a message such as "Please check the paper size to be set" is also displayed, the so-called "user-friendly machine" is further improved.
[0026]
In the above embodiment, the sheet bundle detection sensor 28 of the first sheet storage unit 11 is installed at one position on the rightmost side in the figure. Jam detection becomes possible. Although the sheet bundle detection sensor 28 detects only the arrival timing of the bottom of the leading end of the sheet when transferring the sheet, the presence or absence of the sheet in the first sheet storing unit 11 is detected immediately after the tray 17 is set in the machine. You may. Normally, the presence or absence of the sheet P1 in the first sheet storage unit 11 is performed by the paper end detection 27 after the bottom plate 16 is raised. However, this method is wasteful because the bottom plate rising time is required. If the sheet bundle detection sensor 28 is used so as to detect the presence or absence of a sheet only after the tray 17 is set, the bottom plate 16 is raised only when there is a sheet and the operation proceeds to the sheet feeding operation. It is possible to immediately move to the sheet transfer operation from the printer.
[0027]
【The invention's effect】
As described above, the sheet feeding device and the image forming apparatus using the same according to the present invention have an effect that the jam at the time of sheet transfer can be accurately detected and the device can be prevented from being damaged.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a schematic diagram of a copying machine to which a first embodiment of the present invention is applied.
FIG. 2 is a plan view showing an upper stage of a paper feeding unit provided in the copying machine of FIG. 1;
FIG. 3 is a side view of the same.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 contact glass 2 optical system 3 photoreceptor 4 charger 5 developing device 6 transfer / separator 7 cleaning unit 8 fixing unit 9 registration roller pair 10 conventional tray 11 first paper storage unit 12 second paper storage unit 13 14 Manual paper feeder 15 Paper feeder 16 Bottom plate 16a Bottom plate opening 17 Tray 17a Tray hole 18 Pressurizing plate 19 Limit switch 20 Lowering detection sensor 21, 22, 29, 30 Side fence 23, 24, 32 Back fence 25 Pressure shaft 26 Drive unit 27 Paper end sensor 28 Sheet bundle detection sensor 31 Bottom plate 31a Hole in bottom plate 33 Timing belt 38 Forward / reverse rotation motor 39 Home sensor 40 Push sensor 41 Filler L1, L2, L3, L4 Guide rails P1, P2 Paper

Claims (3)

A first sheet storage unit having a movable bottom plate and capable of stacking a plurality of sheets on the bottom plate; sheet feeding means for feeding sheets one by one from the first sheet storage unit; A second paper storage unit that is arranged substantially horizontally and in parallel with the one paper storage unit and is capable of stacking a plurality of sheets, and the paper loaded in the second paper storage unit is collectively transferred to the first paper storage unit And a transfer means for transferring a sheet bundle, wherein at least one opening is formed in a movable bottom plate on which sheets of the first sheet storage section are stacked, and a bottom end of a sheet bundle to be transferred to the first sheet storage section is detected. Sheet bundle detecting means are provided at the bottom of the first sheet accommodating portion so as to correspond to the at least one opening, respectively, and the sheet accommodated in the first sheet accommodating portion is transferred to the transfer means side via the bottom plate. A bottom plate pressurizing means for urging the bottom plate pressurizing means. Sheet feeding apparatus the paper in the second sheet storage portion, characterized by comprising a releasable when transferred to the first sheet accommodating portion. 2. The sheet feeding device according to claim 1, wherein the opening provided in the movable bottom plate of the first sheet storage portion also serves as a paper end detection opening for detecting the presence or absence of a sheet during the sheet feeding operation. Paper equipment. And a means for counting a transfer time from a transfer start time of the sheet by the transfer means to a time at which the sheet bundle detecting means detects the bottom end of the sheet bundle, wherein the counting means comprises: Means for judging a jam during sheet transfer when the counted transfer time exceeds a predetermined time, and stopping the transfer operation of the transfer means and displaying a jam message on the display unit according to the judgment output of the judgment means. An image forming apparatus comprising:

Images