JPH05132194A - Paper feed device - Google Patents

Abstract

PURPOSE:To realize the stable feed of paper sheets by providing a pressing means capable of changing contact pressure between a sheet feed means to feed sheets on a stack tray and a sheet, and enabling a sheet pressing force to be automatically changed via the control of the pressing means, according to a sheet size, quality or the like. CONSTITUTION:When this device is used for the automatic document feed device of a copying machine, a movable pressing plate 112 is so fitted as to be capable of free oscillation about an oscillation axis 114 at the document feed downstream end of a stack tray, and a drive plate 118 is fixed to the shaft 114 with a screw. A torsion spring 119 coiled around the oscillation shaft 114 is provided between the movable pressing plate 112 and the drive plate 118. Also, an actuator section (shading section) 118A is bent at two positions behind the drive plate 118 for actuating a home position detection sensor and a pressing force detection sensor. Furthermore, the oscillation shaft 114 is caused to oscillate with a pressing force motor connected to the end thereof. This motor is controlled and driven, according to a pressing force obtained through the retrieval of a pressing force setting table on the basis of a detected document size.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-like sheet feeding device in an image forming apparatus such as a copying machine, a facsimile, a printer, etc., and more particularly to feeding an original in an automatic document feeder, or accommodating it in a cassette or an intermediate tray. Sheet-like recording paper, and improvement of conveyance.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a facsimile or a printer, the sheet-like paper accumulated on a paper tray, a paper feed cassette, a paper stacker, a stack tray for placing originals, etc. Alternatively, there is provided a sheet feeding device that sequentially takes out the sheets one by one from the lowest order and sends the sheets to an image recording unit or the like.

For example, in order to transfer a toner image formed on an image forming body onto a transfer material in a timely manner, a recording paper conveyed from a paper feed cassette through a pickup roller and a feed roller is abutted against a registration roller in advance. The slack is kept stopped, and the registration rollers are driven in synchronization with the scanning start operation of the optical system for reading the document information, and the recording paper is nipped and conveyed to the transfer area. In the paper sheet feeding / discharging device disclosed in Japanese Unexamined Patent Publication No. 50-73374, a vacuum suction mechanism is used, and detection is performed by a thickness detection lever and a pressure detection lever that are displaced according to the thickness and pressure of the paper sheet. Then, the motor is driven to control the conveyance speed of the paper sheets.

In the double-sided recording / multi-recording, the recording re-feeding device in the intermediate tray also feeds out and feeds the recording paper, as in the above paper feeding device.

In the automatic document feeder, the originals fed one by one from the original placing table (stack tray) on which sheet-like originals (hereinafter simply referred to as originals) are placed by the sheet feeding device are conveyed by the conveying belt. After being fed onto the glass and exposed by the exposure section lamp in the main body of the copying machine, the sheet is further carried out onto the document discharge table. JP 60-36248
The bottom sheet separating / feeding device disclosed in Japanese Patent Publication is to supply compressed air between the sheets between the sheets to separate the sheets, and to control the flow rate of air according to different sheet stack amounts. Is becoming

[0006]

In a high speed copying machine capable of copying at a speed of 50 sheets or more per minute,
There is a need for an automatic document feeder that feeds a document onto a platen glass in a quick and reliable manner, and a recording sheet feeder that feeds copy sheets from a paper feed cassette or an intermediate tray at high speed. In these automatic document feeders and recording sheet feeders, various original document bundles and recording sheet bundles are stacked on a stack tray or the like until the feeding is completed.
High-speed feeding must be maintained by preventing misfeeds and double feeds. The originals or recording sheets to be sent have remarkably unstable feeding because the feeding conditions differ depending on the size type (for example, B5 to A3), the thickness (thick and thin sheets), and the number of stacks. ..

In order to prevent this problem, the above-mentioned sheet feeding device provided with a vacuum belt device and a vacuum suction mechanism has a complicated mechanism and a large scale, and there are problems such as noise generation. Further, in the paper sheet feeding / discharging device disclosed in the above-mentioned Japanese Patent Laid-Open No. 50-73374, the sheet pressing force can be changed only in two steps, and it cannot meet the complicated feeding conditions.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the sheet feeding device in the automatic document feeder and the recording sheet feeding device, and it is possible to adjust the size of the document and the recording sheet, the paper quality, the number of sheets, etc. Change the sheet pressing force automatically,
The purpose is to ensure and stabilize high-speed sheet feeding. It is another object of the present invention to make it possible to change and set the sheet pressing force at the time of feeding even under conditions specified by the operator, thereby enabling stable feeding in accordance with various feeding conditions.

In the sheet feeding device of the present invention which achieves the above object, a stack tray for stacking and supporting a plurality of sheets, a sending means for sending a sheet in contact with a part of the stacked sheets, and the sending means A feeding unit that is located downstream in the sheet feeding direction and is capable of separating a plurality of sheets one by one, and at least a pair of feeding rollers that is located downstream of the separating unit and that can feed the separated sheets. In the paper apparatus, a size detecting unit that detects the size of the sheets stacked on the stack tray and generates a signal, a pressing unit that can change the contact pressure between the sending unit and the sheet, and a downstream of the separating unit. A sheet passage detecting means located on the side, capable of detecting the edge of the separated sheet, the feeding means, the driving means for driving the pressing means and the conveying roller, And a control means for controlling the driving means, and based on a sheet size detection signal from the sheet size detection means, a pressing force setting table capable of selecting a plurality of variable pressing forces is provided in advance, and the pressing force setting table value is set. The drive of the drive means is controlled based on the above.

Further, the sheet feeding apparatus of the present invention comprises a sheet condition inputting means which can be set before starting sheet feeding, and a size detecting means which detects the size of the sheets stacked on the stack tray and generates a signal. A pressing means capable of changing the contact pressure between the feeding means and the sheet, a sheet passage detecting means positioned downstream of the separating means and capable of detecting the edge of the separated sheet, and the feeding means. Controlling the driving of the driving means based on an input signal of the sheet condition inputting means, the driving means driving the pressing means and the conveying roller, and the control means controlling the driving means. It is characterized by.

Further, in the paper feeding device of the present invention, the size detecting means for detecting the size of the sheets stacked on the stack tray and generating a signal, and the contact pressure between the feeding means and the sheets can be changed. A pressing unit; a sheet passage detecting unit located downstream of the separating unit and capable of detecting the edge of the separated sheet; a feeding unit; a driving unit that drives the pressing unit and the conveyance roller. A preset control means for controlling the driving means, a measuring means for measuring the time from the start of the feeding operation by the driving of the feeding means and the pressing means to the detection of the leading edge of the sheet by the sheet passage detecting means, A reference value and a comparing means for comparing the measured value by the measuring means, and comparing the measured value and the reference value by the comparing means, when a difference of a predetermined time or more occurs, Even without those characterized by changing the pressing force by the pressing means in the next process at the time of the same set.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiments shown in the accompanying drawings.

FIG. 1 is an overall configuration diagram of an image recording apparatus (copier) to which the paper feeding apparatus of the present invention is applied.

In the drawing, 1 is a copying machine main body, 2 is a scanning exposure optical system, 3 is an image forming means around the photosensitive drum 31, and 4 is an image forming means.
Is a copy paper feeding means (paper feeding means), 5 is a copy paper conveying means,
Reference numeral 6 is a fixing device, 7 is a reverse paper discharge switching means, 8 is a reverse carrying means, 9 is a double-sided recording paper carrying means (ADU), and 10 is an automatic document feeder (ADF) with a double-sided document automatic reversing function.

Since the sheet feeding section 41 of the copy sheet feeding means 4, the sheet feeding section 91 of the double-sided recording sheet conveying means 9, and the sheet feeding section 12 of the automatic document feeder 10 have the similar structure, The automatic document feeder 10 will be described in detail.

FIG. 2 shows an automatic document feeder 10 according to the present invention.
FIG. 3 is a partial plan view of the automatic document feeder, and FIG. 4 is a configuration diagram showing a drive system (power transmission system) of the apparatus.

The automatic document feeder 10 is installed on the main body 1 of the copying machine as shown in FIG. 1, and separates one document D from the document placing section 11 for stacking the document bundle. And a document feeder 12 fed from the paper feed unit 12
Transporting unit 13 for transporting the sheet to a predetermined position on the platen glass 21
Then, after the image exposure is completed, the document D sent from the carrying section 13 is discharged to a paper discharge tray or a post-processing device, and
It is composed of a paper discharge reversing unit 14 for reversing the document after image exposure and feeding it again onto the platen glass 21.

A stack tray (document stacking plate) 110 for stacking a stack of documents is fixedly mounted on the document stacking unit 11. On the stack tray 110, a lateral width regulating plate 111 for regulating the lateral width of the document. Is movably installed.

When the stack of documents D is placed on the stack tray 110, the presence or absence of documents on the stack tray 110 is detected by a document set detection sensor (zero document detection sensor) PS1 and is displayed on the control panel of the copying machine main body 1. ADF
The mode is displayed. When the document stack D is set at a predetermined position, the document size (B5 to A3) is detected by the document size sensor PS2 and input to the control unit of the copying machine body 1.

A movable pressing plate (movable pressing member) 112 is provided at the leading end of the stack tray 110 on the downstream side of document feeding, and a swing shaft 114 supported by a bearing 117A provided on one side plate 113A and the other side plate 113B. Each of them is slidable on each of the pins 115 planted in, and can swing about these.

The side plates 113A and 113B are combined with the bottom plate 116 to be integrated. Bearing 117 provided on the side plate 113A
A gear G1 is fixed to the shaft end of a swing shaft 114 that penetrates A and a bearing 117B provided at the rising portion of the fixed bottom plate 116, and meshes with a gear G2 fixed to the drive shaft of the pressing motor M1. ing.

A drive plate (drive member) 1 is attached to the swing shaft 114.
18 is fixed by screws and can swing together. An elastically deformable member (for example, a torsion spring) 119 is wound around the swing shaft 114, and both ends of the elastic deformable member 119 are the drive plates 118.
In the center part, the movable pressing plates 112 can be pressed against each other. At this time, the movable pressing plate 112 and the drive plate 118 are pushed in the opening direction by the torsion spring 119.
The end of 12 abuts against the drive plate 118 so that the gap does not open beyond a certain amount. Also, the torsion spring at this time
The spring force by 119 is adjusted so as to be equal to or less than an initial setting pressure described later.

Actuator portions (light-shielding portions) 118A and 118B are projected by bending at two positions on the back surface of the drive plate 118. The actuator section 118A is
The optical path of the pressure detection sensor (for example, photo interrupter) PS3 fixed to the movable pressure plate 112 is turned on and off.
The actuator 118B detects the home position of the drive plate 118 by turning on / off the optical path of a home position detection sensor (for example, a photo interrupter) PS4 fixedly mounted on the fixed bottom plate 116.

A paper feed unit 12 is provided downstream of the movable pressing plate 112 for feeding originals. The paper feed unit 12 is composed of a document leading edge stopper 120, a drive roller 121, a driven roller 122, a feed belt 123 that winds and rotates both rollers, and a double feed prevention reverse roller 124 located below the feed belt 123. There is. The driving force of the driving motor M2 is transmitted to the driving roller 121 via the electromagnetic clutch CL1.

A transport unit 13 is provided on the downstream side of the document transport of the paper feed unit 12. The transport unit 13 includes a first intermediate transport roller 13
0, the document passage detection sensor PS5, the curved guide plate 131,
Second intermediate conveying roller 132, drive roller 133 and driven roller 13
4 and 3 original pressing roller 135 and tension roller 136
The conveyor belt 137 is stretched between the two.

A clutch C is provided on the shaft of the drive roller 133.
L2 and the brake BRK are pivotally supported and operated by the driving force of the drive motor M2.

The paper output reversing section 14 includes a paper output roller 140 and a switching claw 1.
41, a plurality of conveying rollers 142, 143, 144 and a guide plate 14
It is composed of 5, 146, 147 etc. The paper discharge roller 140 and the transport rollers 142 to 144 are driven by the paper discharge motor M3. The switching claw 141 is driven by the solenoid SOL.

The dashed-dotted line in FIG. 2 shows the transport path of the document D discharged from the discharge reversing unit 14 to the external discharge tray 148.

FIG. 5 shows a document placing portion before placing the document stack D.
11 is a cross-sectional view of the sheet feeding unit 11 and the sheet feeding unit 12, and FIG. 5A is a cross-sectional view centering on the home position detection sensor PS4.
(B) shows a sectional view centering on the pressure detection sensor PS3. 6 is a cross-sectional view showing a process in which the movable pressing plate 112 is driven after stacking the document stack D on the document placing portion 11, FIG. 7 is a cross-sectional view showing a state in which sheets can be fed, and FIG. FIG. 9 shows a flowchart of the paper operation process, and FIG. 9 shows its timing chart. The document feeding operation will be described below.

(1) In the state shown in FIG. 5, the pressing motor M1 is rotated by turning on the main switch of the copying machine body 1, and the movable pressing plate 112 detects the initial stop position by the home position detecting sensor PS4. The pressing motor M1 is stopped. That is, the home position detection sensor (second detection member) PS4 is turned on at the home position. When the main switch is on and the home position detection sensor PS4 is off, the pressing motor M1 is rotated in the reverse direction, the home position detection sensor PS4 is detected to be turned on, and the pressing motor M1 is stopped. Drive plate 118 and movable pressing plate 1
Stop 12 in lowest initial position. If the home position detection sensor PS4 is turned on, the pressing motor M1 is once rotated in the forward direction to move the home position detection sensor P4.
After turning off S4, the motor M1 is then rotated in the reverse direction, and when the sensor PS4 is turned on, the motor M1 is stopped and the home position is reached. This is effective for absorbing the time lag of the drive gear and sensor ON.
At the home position stop position, the clearance L capable of accommodating a predetermined maximum amount of the document bundle D is held.

(2) When the document stack D is placed on the stack tray 110 and the movable pressing plate 112, the document set detection sensor PS1 is turned on and the ADF mode is set. At the same time, the document size sensor PS2 is turned on and the document size is detected (see FIGS. 2 and 8).

(3) When the copy button is turned on, the ADF
Then, the copying can be started, the pressing motor (stepping motor) M1 starts driving rotation, and the movable pressing plate 11 is moved through the driving member 118 fixed to the swing shaft 114 and the spring 119.
2 oscillates and rotates, and its leading edge rises, and the stack of originals D
Lift up. During this ascending process, the swing angle of the swing shaft 114 is adjusted by the pulse encoder A by the rotary encoder or the like.
Are counted (see FIGS. 6 and 7).

(4) When the upper surface of the document stack D stacked on the movable pressing plate 112 is brought into pressure contact with the outer peripheral surface of the feed belt 123, the movable pressing plate 112 stops while holding the document stack. The drive plate 118 is further driven and rotated to rotate counterclockwise while compressing the torsion spring 119, and the distance m between the movable pressing plate 112 and the drive plate 118 is narrowed (m →
m ').

(5) When the distance m reaches the set distance,
The actuator section 118A at one end of the drive plate 118 turns on the pressure detection sensor PS3 fixed to the movable pressure plate 112,
The initial set pressure (for example, 50 g) is reached, and counting of the count A is stopped.

(6) The paper bundle thickness of the document bundle D is detected by the output of the count A, and it is predetermined by the document size sensor PS2 detected previously, or the setting input of thick paper or thin paper. The designated pulse is determined by the pressing force setting table in Table 1 below.

[0036]

[Table 1]

The original sheet bundle thickness is detected by the count A count value by the pressure detection sensor PS3, and in Table 1 above, the sheet bundle thickness is classified into, for example, three stages of high, medium and low.

As the original paper size, for example, B5 to
A3 size is set, which corresponds to the original size sensor PS2.
Detected by. When a stack of manuscript papers of a plurality of manuscript sizes is mixedly mounted, the user designates by pressing a mixed mounting key arranged on the operation panel of the copying machine main body.

The thickness of one original sheet is designated by pressing a thin paper key or a thick paper key arranged on the operation panel.

As described above, the bundle of original sheets and the original size are automatically detected by the respective sensors, and the mixed loading of originals and the sheet thickness are manually set.

The pressure pulse table shown in Table 1 is preset by these detected values and manual setting,
It is stored in a non-volatile memory, and the count B is determined by these sheet condition input means.

According to the pressing force setting table shown in Table 1, the count B (setting table value) is larger as the size of the original is larger, and the larger the number of original sheets is, the larger the number of sheets is and the thicker one original is. It is set to be larger, and accordingly, the pressing force of the document stack is set to be larger. In addition,
When a plurality of types of originals having different sizes are mixed and stacked (mixed) on the stack tray 110, the count B is set as an intermediate size of B5 to A3.

Based on the input signal from the seat condition input means, the drive of the drive means is variably controlled by the control means. That is, when it is specified that one sheet of the document D stacked on the stack tray 110 is thin, the control means causes the pressing motor M to be pressed.
1 is driven and count-controlled by a rotary encoder to move the drive plate 118, raise the movable pressing plate 112, and press the document stack with a low predetermined pressure having a small count B value, thereby causing no document feed or Prevents damage to document paper and stains on the document surface. This predetermined pressure is variably controlled in multiple stages depending on the thickness of the original bundle.

Alternatively, when the thin original paper is set, the drive motor M2 is controlled to be decelerated to set the feed belt 123 of the paper feeding device and the intermediate conveying rollers 130 and 132 to low speed rotation, and the original D is fed. The paper speed is reduced to stabilize the feeding of thin originals and prevent double-feeding and jamming.

Further, when the sheet condition input means specifies and inputs that the thickness of one sheet of the original document D is thick, the control means sets a large count B value, and the movable pressing plate 112 is set to a high predetermined pressure. The stack of documents on the stack tray 110 is pressed. Alternatively, the control means selectively controls the sheet feeding speed of the sheet feeding device to be low.

Further, when a plurality of types of originals D having different sizes are stacked on the stack tray 110, a mixed loading designation input is performed by the key of the operation panel of the sheet condition input means. Regardless, the control means selectively sets the pressure of the movable pressing plate 112 to a predetermined pressure. This predetermined pressure is variably controlled in a plurality of stages by selecting the count B in the table of Table 1 depending on the thickness of the original bundle.

(7) Count B by a designated pulse by the sheet size detection signal or the sheet condition input signal
Is input, and the driving plate 118 is driven to start counting the count B. When the driving plate 118 is swung until the designated count number B is counted up, the torsion spring 119
The amount of wrapping around increases, the elastic force changes almost linearly, and the pressing force increases.

(8) When the count B is counted up, the movable pressing plate 112 presses the document D against the feed belt 123 with a predetermined pressing force (for example, 100 g) to complete the specified pressing force, and then the pressing motor M1 is operated. Stop driving.

(9) Next, drive motor (main motor)
M2 is turned on, and at the same time, electromagnetic clutches CL1, CL2
Also turns on, and paper feeding starts.

That is, the original D in the upper layer is sent out by the feed belt 123 which starts to rotate by the driving force of the motor M2, and the uppermost original D among the plurality of originals D sent out by the reverse roller 124. Only the sheets are separated and sent.

(10) One sheet of the document D separated and fed is nip-conveyed to the intermediate conveyance roller 130, and when the leading end of the document D crosses the document passage detection sensor PS5, the driving roller is driven.
The clutch CL1 driving 121 is turned off, and the feed belt 123 is driven to rotate until the trailing edge of the document D has passed through the sensor PS3, and then stops.

(11) Further, the document passage detection sensor PS
5 is turned on, the pressing motor M1 is switched to the reverse rotation, and the drive plate 118 and the movable pressing plate 112 are lowered,
Release the pressure.

(12) When the home position detection sensor PS4 detects that the drive plate 118 has returned to the initial position, the pressing motor M1 is stopped.

(13) When the trailing edge of the first document D passes and the document passage detection sensor PS5 is turned off, the next document is continuously pressed, and the next document is kept waiting in the pressed state.

Next, another embodiment of the sheet feeding device according to the present invention will be described with reference to the control block diagram of FIG. 10 and FIG.

After the driving plate 118 starts to swing, the feeding belt 123 starts to rotate and the feeding operation starts, and then the measuring means such as timer counting or encoder pulse counting starts to measure the passage of the original D through the original. The time until the passage detection sensor PS5 is detected is measured, and the measured value is compared with a preset reference value by a comparing means. When a difference of a predetermined time or more occurs, at least the same setting is made. The pressing force by the pressing means in the next process of (1) or the feeding speed is controlled to be changed. The above-mentioned time difference occurs, for example, due to a change in the friction coefficient due to abrasion of the surface of the feed belt 123 or the like when a document is fed, slippage occurs, or the separation and feeding failure occurs. There is a risk of paper defects. In order to prevent this, when detected by the comparison means, this signal is fed back to the control device to increase the pressing force or feed speed of the next original document or after feeding a predetermined number of sheets or after setting the next original bundle. Measures such as speed reduction are automatically set.

FIGS. 11A, 11B and 11C are sectional views showing the essential parts of other embodiments of the pressing mechanism of the sheet feeding device according to the present invention. In the figure, parts having the same functions as those in the above embodiment are designated by the same reference numerals. Further, the points different from the above embodiment will be described.

FIG. 11 (A) shows a structure in which a feed roller 125 which is driven to rotate is supported by a movable pressing plate 112 from above the document stack D placed on the stack tray 110 so as to be swingable. The movable pressing member 112 maintains a predetermined pressing force by the operation of a drive plate 118 which is rocked by a rocking shaft 114 which is driven by a pressing motor M1 and a torsion spring 119 in the same manner as described above, and a document bundle is held. The upper surface of D is pressed. With respect to the document D that has been fed up by the pressure contact rotation of the delivery roller 125, only one document is fed by the separating means 126 for preventing double feeding.

FIG. 11B shows a bottom feeding device. A pressing means including a movable pressing plate 112, a drive plate 118, a torsion spring 119, and a swing shaft 114 provided above the stack tray 110 presses the document stack D with a predetermined pressing force. The lower feeding roller 125 feeds the lower document of the document D to the separating unit 126.

FIG. 11C also shows the bottom feeding device. In this embodiment, the pressing means is located below and the movable pressing plate 112 is
The drive-rotatable feed roller 125 provided at the leading end of the sheet feeds the document on the bottom layer and advances it to the separating means 126.

The pressing force by the pressing means described above can be automatically changed according to the conditions such as the document size, the paper width, the paper thickness, etc., so that the feeding is more stable. Also, the pressing force can be changed by setting the specified conditions by the user.

In each of these embodiments, the pressure is released by returning to the home position every time, but these may be pressure-bonded all the time until the original is exhausted, or the release may be returned by a fixed amount.

[0063]

Since the paper feeding apparatus of the present invention is constructed as described above, it has the following effects.

Since the sheet pressing force for pressing and feeding the sheet bundle placed on the stack tray can be automatically changed according to the paper size, the paper thickness, the number of paper bundles, etc.,
The sheet feeding can be stabilized.

Since the sheet pressing force can be changed in multiple stages,
Stable paper feeding is possible under all sheet conditions.

Even when the sheet is fed at high speed, it is stable without causing feeding trouble.

No large-scale structure such as suction paper feeding is required, and there is no problem such as noise generation.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an image recording apparatus to which a sheet feeding device of the invention is applied.

FIG. 2 is a sectional view of an automatic document feeder according to the present invention.

FIG. 3 is a partial plan view of the automatic document feeder.

FIG. 4 is a schematic diagram showing a drive system of the automatic document feeder.

FIG. 5 is a sectional view of a document placing section and a sheet feeding section of the automatic document feeder.

FIG. 6 is a cross-sectional view showing an operation process of the pressing means of the paper feeding device according to the present invention.

FIG. 7 is a cross-sectional view showing a paper feed possible state of the paper feeding device.

FIG. 8 is a flowchart showing a paper feeding operation process of the paper feeding device.

FIG. 9 is a timing chart of the paper feeding device.

FIG. 10 is a control block diagram of another embodiment of the paper feeding device according to the present invention.

FIG. 11 is a cross-sectional view of essential parts showing another embodiment of the paper feeding device according to the present invention.

[Explanation of symbols]

 1 Copying Machine Main Body 10 Automatic Document Feeding Device 11 Document Placement Section 110 Stack Tray (Original Placement Plate) 111 Horizontal Width Regulation Plate 112 Movable Pressing Plate (Movable Pressing Member) 114 Swing Shaft 118 Driving Plates (Driving Members) 118A, 118B Actuator section 119 Torsion spring (elastically deformable member) 12 Paper feed section 120 Document leading edge stopper 121 Driving roller 123 Feed belt 124 Reverse roller 125 Sending roller 126 Separating means 13 Conveying section 130 First intermediate conveying roller 132 Second intermediate conveying roller 133 Driving Roller 137 Conveyor belt 14 Paper discharge reversing unit 2 Scanning exposure optical system 21 Platen glass 3 Image forming means 31 Photoconductor drum 4 Copy paper feeding means 41 Paper feeding section 9 Double-sided recording paper feeding means 91 Paper feeding section A, B Pulse count D Document (sheet), document bundle M1 Pressing motor M2 Drive motor (main motor) PS1 Document set detection sensor PS2 Document size Sensor PS3 Press detection sensor (first detection member) PS4 Home position detection sensor PS5 Original passage detection sensor (second detection member)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G03G 15/00 109 7369-2H H04N 1/00 108 L 4226-5C

Claims (10)

[Claims] 1. A stack tray for stacking and supporting a plurality of sheets, a sending-out means for sending a sheet in contact with a part of the stacked sheets, and a plurality of sheets positioned downstream of the sending-out direction in the sheet feeding direction. In the paper feeding device, which is composed of a separating means capable of separating the sheets one by one, and at least a pair of conveying rollers located downstream of the separating means and capable of conveying the separated sheets, the sheets are stacked on the stack tray. A size detecting means for detecting the size of the sheet and generating a signal, a pressing means capable of changing the contact pressure between the feeding means and the sheet, and a downstream side of the separating means,
A sheet passage detecting means capable of detecting the edge of the separated sheet, the feeding means, a driving means for driving the pressing means and the conveying roller, and a control means for controlling the driving means, A pressing force setting table capable of selecting a plurality of variable pressing forces is provided in advance on the basis of the sheet size detection signal from the sheet size detecting means, and the drive of the driving means is controlled based on the pressing force setting table value. Characteristic paper feeding device. 2. A thickness detecting means for detecting the thickness of a sheet bundle stacked on the stack tray, wherein a plurality of variable pushers are provided based on the sheet size detection signal and the sheet bundle thickness detection signal. A pressing force setting table capable of selecting a pressure is provided, and the setting table value is set such that the pressing force is increased on the side where the sheet size is large or the sheet bundle thickness is thick. The paper feeder described. 3. A stack tray for stacking and supporting a plurality of sheets, a sending-out means for sending a sheet in contact with a part of the stacked sheets, and a plurality of sheets located downstream of the sending-out direction in the sheet feeding direction. Can be set before the start of sheet feeding in a sheet feeding device including a separating unit capable of separating each sheet from the sheet and at least a pair of conveying rollers located downstream of the separating unit and capable of conveying separated sheets. Sheet condition inputting means, size detecting means for detecting the size of the sheets stacked on the stack tray and generating a signal, pressing means capable of changing the contact pressure between the feeding means and the sheets, and the separating means. A drive for driving the sheet passage detecting means located downstream of the means and capable of detecting the edge of the separated sheet, the feeding means, the pressing means and the conveying roller. A sheet feeding device comprising: a sheet feeding unit and a control unit that controls the driving unit, and controls the driving of the driving unit based on an input signal of the sheet condition input unit. 4. The sheet condition input means relates to the paper thickness of the sheets stacked on the stack tray, and when it is input that the paper thickness of the sheets is thin, the control means causes the pressing means. 4. The sheet feeding device according to claim 3, wherein the pressing force of is selected and set to a low predetermined pressure. 5. The sheet condition input means relates to the paper thickness of the sheets stacked on the stack tray, and when the sheet thickness of the sheets is designated and input, the control means supplies the sheet. 4. The paper feeding device according to claim 3, wherein the paper feeding speed of the paper device is selectively controlled to be a low speed. 6. The sheet condition inputting means relates to a sheet thickness of sheets stacked on the stack tray, and when the sheet thickness of the sheets is designated and inputted, the pressing means is pressed by the control means. 4. The sheet feeding device according to claim 3, wherein the pressure of the means is selectively set to a high predetermined pressure. 7. The sheet condition input means relates to a sheet thickness of sheets stacked on the stack tray, and when the sheet thickness of the sheets is designated and input, the control means supplies the sheet. 4. The paper feeding device according to claim 3, wherein the paper feeding speed of the paper device is selectively controlled to be a low speed. 8. The sheet condition input means relates to stacking a plurality of sheets of different sizes on the stack tray, and when the stacking of sheets of a plurality of different sizes is designated and input, 4. The pressure of the pressing means is selectively set to a predetermined pressure by the control means regardless of a size detection signal.
The paper feeder described in. 9. The sheet condition inputting means relates to loading sheets of different sizes on the stack tray, and when it is designated and input that sheets of different sizes are loaded. 4. The paper feeding device according to claim 3, wherein the control means reduces the paper feeding speed of the paper feeding means. 10. A stack tray for stacking and supporting a plurality of sheets, a sending-out means for sending out the sheets in contact with a part of the stacked sheets, and a plurality of sheets located downstream of the sending-out direction in the sheet feeding direction. In the paper feeding device, which is composed of a separating means capable of separating each sheet from the sheet and at least a pair of conveying rollers located downstream of the separating means and capable of conveying the separated sheets, the sheets are stacked on the stack tray. Size detection means for detecting the size of the sheet and generating a signal, pressing means for changing the contact pressure between the feeding means and the sheet, and an edge of the separated sheet positioned downstream of the separating means A sheet passage detecting unit capable of detecting a sheet, a feeding unit, a driving unit that drives the pressing unit and the conveyance roller, a control unit that controls the driving unit, and Measuring means for measuring the time from the start of the feeding operation by driving the notifying means and the pressing means until the sheet passage detecting means detects the leading edge of the sheet, a preset reference value, and a measured value by the measuring means. And comparing the measured value with the reference value by the comparing means, and when a difference of a predetermined time or more occurs, at least the pressing force by the pressing means in the next process at the same setting is changed. A paper feeding device characterized by the above.