JPH10129865A - Sheet feed device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate, and feed sheets even a sheet having a folded back part like an envelope stably by setting type of sheet and changing sheet supply and feed time depending on type of sheet. SOLUTION: A flapper solenoid 33 is energized again after the time which is set in advance elapses after a pick up roller 9 rises by the normal operation when it is judged that the sheet which is being supplied and fed is an envelope having a folded back part by a sheet type setting means. A pick up cam 30 is rotated, a lift up lever 29 is oscillated to lower a pick up roller shaft 9a, the pick up roller 9 is brought into contact with a face having no folded back part of the envelope, and the envelope is pushed from behind. The pick up roller 9 comes into contact with the face having no folded back part of the envelope only during the time determined by the shape and angular speed of the pick up cam 30, leaves the sheet face, and rises. As a result, the supply and feed time by means of the pick up roller 9 becomes longer than that in case of ordinary sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus used in an image forming apparatus such as a copying machine or a printer, and an image forming apparatus using the same. The present invention relates to a sheet feeding device capable of feeding.

[0002]

2. Description of the Related Art Conventionally, in a copying machine or a printer, a large number of sheets are stacked and set in order to automatically feed the sheets, and the sheets are separated and fed one by one by a feeding roller or the like. Like that.

Various methods have been proposed for the sheet separating mechanism, including a feed rotator rotating in a sheet feeding direction and a retard rotator rotating in a sheet returning direction. Some use a separation mechanism. .

[0004]

In the above-mentioned printers and the like, it is common to record images by separating and feeding cut sheets, which are so-called plain papers, one by one. In many cases, a plurality of envelopes are set and separated and fed one by one to automatically record the address and sender's name.

[0005] However, unlike the cut sheet, the envelope has a folded portion for sealing, and in the folded portion, two sheets are folded in spite of being a single envelope. ing. For this reason, in particular, when the separation is performed by the retard separation mechanism, the separation operation is performed in the folded portion, and the leading end portion may be buckled to cause a jam (paper jam).

[0006] The present invention is to solve the above problems,
An object of the present invention is to provide a sheet feeding apparatus capable of stably separating and feeding even a sheet having a folded portion like an envelope, and an image forming apparatus using the same.

[0007]

A typical configuration according to the present invention for achieving the above object is to provide a sheet feeding apparatus for separating and feeding sheets, for applying a feeding force to the sheets. A feed rotator that rotates in a sheet feeding direction and a retard rotator that rotates in a sheet return direction in order to separate sheets fed by the feeding unit into sheets one by one. A separating unit, a type setting unit for setting a type of the sheet, and a control unit for changing a sheet feeding time by the feeding unit according to the type of the sheet.

In the above-described configuration, when a sheet having a folded portion such as an envelope is fed, the sheet feeding time of the feeding means is lengthened so that the folded portion is located at the separating means. However, since the sheet feeding force is increased, the sheet is separated and fed without buckling.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a sheet feeding apparatus and an image forming apparatus according to an embodiment of the present invention will be specifically described with reference to the drawings.

[First Embodiment] A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory diagram of the overall configuration of an image forming apparatus using a sheet feeding apparatus.
FIG. 2 is an explanatory view of the configuration of the sheet feeding device, FIG. 3 is an explanatory view of the configuration of the separating means, FIG. 4 is an explanatory view of the frictional force between the separating means and the sheet when feeding a normal sheet, and FIG. Explanatory diagram of up-down signal of pickup roller, FIGS. 6 to 8
FIG. 9 is an explanatory diagram of a configuration of a sheet type setting unit, and FIG. 9 is an explanatory diagram of a frictional force between the separating unit and the sheet when feeding an envelope.

Here, as the order of the description, first, the overall configuration of the image forming apparatus will be described, and then the configuration of the sheet feeding apparatus will be described.

{Overall Description of Image Forming Apparatus} In FIG. 1, a main body A of the image forming apparatus has a scanner section B serving as image reading means for reading image information on the image surface of a book document at an upper portion thereof, and a lower portion thereof at a lower portion thereof. It has an image forming section C serving as an image forming means, and further includes a sheet feeding device D attached to a lower portion thereof.

The scanner section B includes a scanning system light source 1, a platen glass 2, an original pressure plate 3, which can be opened and closed with respect to the apparatus main body A, a mirror 4, a lens 5, a light receiving element (photoelectric conversion element) 6, and an image processing section. And so on. Then, a book document, a sheet document, or the like such as a book, cardboard, or curled paper is placed on the platen glass 2 with the document surface facing down.
The back side is pressed by the document pressing plate 3 and set in a stationary state.
When the reading start key is pressed, the scanning system light source 1 scans the lower part of the platen glass 2 in the direction of arrow a in FIG. Image information of a document read by the scanning system light source 1 is processed by an image processing unit, converted into an electric signal, and transmitted to a laser scanner 7 as an optical system.

Here, the image forming apparatus main body A functions as a copying machine when the processing signal of the image processing section is input to the laser scanner 7, and functions as a printer when the output signal of the personal computer is input. If a transmission signal from a facsimile device of another device is input or a processing signal of the image processing unit is transmitted to a facsimile device of another device, the device functions as a facsimile device.

On the other hand, a sheet cassette 8 is mounted below the image forming section C. The sheet cassette 8 is composed of a lower cassette 8a and an upper cassette 8b as one feeding unit. In this embodiment, three feeding units U1, U2, and U3 are mounted, and six cassettes are mounted. One upper feeding unit U1 is detachably attached to the apparatus main body A, and two lower feeding units U2 and U3 are detachably attached to the sheet feeding device D.

The sheets accommodated in the cassettes 8a and 8b are fed out by a pickup roller 9 which is a feeding rotating body as will be described later, and are fed by a feed roller (rotating body rotating in a sheet feeding direction) constituting a separating means. ) 10 and retard roller (rotating body that rotates in the direction to return the sheet) 11
After the sheets are separated and fed one by one by the cooperative action of the rollers, they are conveyed by conveying rollers 12 and 13 constituting conveying means, guided to registration rollers 14, and synchronized with the image forming operation by the rollers 14. Is fed to the image forming section C.

The image forming section C includes an electrophotographic photosensitive drum 1
5, image writing optical system 16, developing unit 17, and transfer charger 1
8 and so on. A laser beam corresponding to image information emitted from the laser scanner 7 is scanned by the image writing optical system 16 on the surface of the photosensitive drum 15 uniformly charged by the charger to form a latent image. A toner image is formed on the image by the developing device 17, and the toner image is transferred onto the first surface of the sheet by the transfer charger 18 on the sheet conveyed in synchronization with the rotation of the photosensitive drum 15 by the registration roller 14.

In FIG. 1, reference numeral 19 denotes a conveying belt for conveying a sheet on which a toner image is formed, reference numeral 20 denotes a fixing device, and reference numeral 21 denotes a fixing device.
Denotes a discharge roller. The sheet on which the toner image is formed is conveyed to the fixing device 20 by the conveyance belt 19, and is heated and pressed to fix the toner image on the sheet surface.
The sheet is discharged and stacked on a tray 22 disposed outside the apparatus by discharge rollers 21.

When images are recorded on both sides of the sheet, the sheet discharged from the fixing device 20 is discharged
When the rear end of the sheet passes the branch point 23, the discharge roller 21 rotates in the reverse direction, and the sheet is once placed on the double-sided tray 24, and is then conveyed by the conveying rollers 12 and 13,
The sheet that has reached the registration roller 14 and has been inverted is formed with an image on the second surface in the same manner as described above, and then discharged and stacked on the tray 22.

{Sheet Feeding Apparatus} Next, the structure of the sheet feeding apparatus D will be described. The sheet feeding apparatus D separates the sheets stored in the sheet cassette 8 and fed one by one by the feeding means. And then feed it.

The feeding means is constituted by a pick-up roller 9 which is in an up state when the sheet is not fed, and is in a down state when the sheet is fed and which can rotate up and down.

Here, the up-down configuration of the pickup roller 9 and the configuration of the lifter that raises the sheets stored in the cassette 8 to the feeding position in accordance with the configuration will be described.
A description will be given of a case where a normal sheet is fed.

In FIG. 2, the sheet S is stored in the cassette 8
The cassette 8 is stacked on a sheet stacking plate 25 rotatably attached to the bottom of the cassette 8, and the cassette 8 is configured to be attachable to the apparatus main body A in the direction of arrow d in FIG.

The sheets S in the cassette 8 are sent out from the uppermost side by a pickup roller 9, and are separated and fed one by one by the action of a feed roller 10 and a retard roller 11.

The roller shaft 9a of the pickup roller 9
The roller shaft 10a of the feed roller 10 is connected and supported by a roller holder 26, and the pickup roller 9 is supported to be swingable around the feed roller 10,
Further, it is urged toward the seat surface by a spring (not shown).

One end of the pickup roller shaft 9a is inserted into a long hole 27a formed in the feeding frame 27 and extends to a lifter mechanism. And the feeding frame
A lift-up lever 29 is rotatably attached to a shaft 28 integrally formed with the shaft 27, and is urged in a clockwise direction (direction of an arrow e in FIG. 2) by a spring 29a.

Therefore, one end of the lift-up lever 29 is in contact with the pickup roller shaft 9a. The other end of the lift-up lever 29 extends to the vicinity of the pickup cam 30, and when the pickup cam 30 rotates, the lift-up lever 29 swings.

The pick-up cam 30 is formed coaxially and integrally with the side of a pick-up gear (missing tooth gear) 32 having only a part of the teeth facing the gear 31. The pickup gear 32 is urged in the counterclockwise direction (the direction of the arrow f in FIG. 2) by an unillustrated urging means. In this embodiment, the pickup gear 32 is picked up by a flapper type solenoid 33 against the urging means. The rotation of the cam 30 is regulated.

Reference numeral 34 denotes a main motor of the image forming apparatus main body A, and a drive input from the motor 34 is a gear 35
The gear 31 is constantly rotated in the direction of arrow g in FIG.

Reference numeral 36 denotes a lifter for moving the sheet stacking plate 25 of the cassette 8 up and down. At one end of the lifter 36, a ratchet gear 37 is integrally formed.

A lift-up gear (partially toothed gear) 38 having only a part of teeth and disposed opposite to the gear 31 is provided with a lift-up cam 39 on the same axis as the lift-up cam 39. By rotating the feed pawl 40 around the shaft 41 by the rotation of, the lifter 36 is raised by sequentially feeding the ratchet gear 37 one tooth at a time by the reverse rotation preventing function of the lock claw 42. Thereby, the sheet S in the cassette 1 is lifted up.

In FIG. 2, reference numeral 43 denotes a lifter trigger lever, which is pivotally supported by a shaft 28 integrally formed with the feeding frame 27, and which is clockwise rotated by a spring 44 (see FIG. 2). It is urged in the direction of arrow h in FIG. 2). One end of the lifter trigger lever 43 has a function as a rotation restricting member of a lift-up gear 38 integrated with the lift-up cam 39, and the other end of the lever 43 is used when the pickup roller 9 is lowered to a predetermined height. It is arranged so as to be in contact with the pickup roller shaft 9a. That is, when the pickup roller shaft 9a is lowered to a predetermined height, the restriction portion at the other end of the lifter trigger lever 43 releases the rotation restriction of the lift-up cam 39, the lift-up cam 39 rotates, and a mechanism (not shown) The feed pawl 40 is swung to raise the lifter 36.

When the uppermost sheet surface of the sheet S rises due to the rise of the lifter 36, the pickup roller abutting on the sheet surface rises, and the lifter trigger lever 43 moves clockwise (in the direction of arrow h in FIG. 2). , And returns to the position where the rotation of the lift-up cam 39 is regulated again. By repeating this operation, the sheet S in the cassette 8 is
Of the uppermost sheet surface becomes substantially constant.

As a result, the apparatus enters a standby state in which sheets S can be fed. Thereafter, by exciting the flapper solenoid 33 in conjunction with the feed start signal, the pickup cam 30 is rotated, the lift-up lever 29 swings, the pickup roller shaft 9a is lowered, and the pickup roller 9 And the sheet S can be fed out.

The pickup roller 9 comes into contact with the sheet surface of the sheet S for a time determined by the shape and the angular velocity of the pickup cam 30, and then moves up and away from the sheet surface. During this time, the driving of the feed roller 10 and the retard roller 11 by the driving source described above is started, and the sheets S stacked in the cassette 8 are separated and fed one by one. When the lowering, the one end of the lifter trigger lever 43 is pushed up by the pickup roller shaft 9a, the rotation restricting member of the lift-up cam 39 is released, and the lifter rises by one latch,
The seat height returns.

By repeating this operation, the height of the seat surface is kept substantially constant. Through a series of these actions,
The pickup roller 9 comes into contact with the sheet surface only when the sheet S is fed out of the cassette 8, and is separated from the sheet surface at other times, thereby maximally preventing the sheet S from being double-fed by the pair of the feed roller 10 and the retard roller 11. And can reliably prevent double feeding.

Next, the operation of the feed roller 10 and the retard roller 11 will be described with reference to FIGS.

FIG. 3 is a partially detailed view of a feeding apparatus using a retard separation system. In this figure, reference numeral 45 indicates that when two or more sheets of paper are sandwiched between the feed roller 10 and the retard roller 11 and a paper jam occurs, the first sheet is pulled out.
A one-way bearing for preventing reverse rotation of the drive gear for preventing the second sheet from being fed in the discharge direction, 46 is a drive pulley for rotating the feed roller shaft 10a, 47
Is a gear for obtaining rotational torque from the drive motor 34 (see FIG. 2) in the main body.
This is a timing belt for transmitting rotational torque in the same direction as the feed roller 10.

Reference numeral 49 denotes a drive shaft of the retard roller 11
Is a torque limiter, and 52 is a coupling for rotating the retard roller 11. Reference numeral 53 denotes a pressure arm for pressing the retard roller to apply a sheet feeding force between the feed roller 10 and the retard roller 11, and reference numeral 54 denotes a pressure roller attached to the tip of the pressure arm. The pressing force is applied to the retard roller 11 through the shaft 57 by the coil spring 55 applying a torque in the direction of arrow T to the retard pressure adjusting arm 56.

Numeral 58 is a retard roller bearing, and numeral 59 is a retard roller shaft which penetrates the retard roller 11 and has a coupling 52 attached to an end.

The sheet separating operation by the separating means having the above configuration will be described with reference to FIG.

FIG. 4A shows a state in which the sheet fed by the pickup roller 9 enters the nip between the feed roller 10 and the retard roller 11 without double feeding. Here, μBRP is a friction coefficient between the sheet S and the feed roller 10, μCRP is a friction coefficient between the sheet S and the retard roller 11, and M is a torque given by the torque limiter for returning the multi-feed sheet. P is the pressing force of the retard roller 11 given by the spring,
r is the rotation radius of the retard roller 11.

Here, in FIG. 4A, conditions for feeding a normal sheet (a sheet having no folded portion such as an envelope) without the feed roller 10 slipping are as follows.

ΜBRP · P = μCRP · P (Equation 1)

Further, considering the balance of the rotation of the retard roller 11 both when the slip between the retard roller 11 and the sheet S does not slip and when the sheet S is slipping, the relationship is as follows.

ΜCRP · P · r ≧ M (Equation 2)

Therefore, the following equations must be satisfied from Equations 1 and 2.

ΜBRP · P · r ≧ M (Equation 3)

Next, FIG. 4B will be described. This shows the case where the retarded sheet S is returned by the retard roller 11 after the sheet S fed by the pickup roller 9 enters the nip without being double fed. Where μ
PP is a coefficient of friction between the sheets S. The conditions under which the paper is completely separated and sent in FIG.

ΜBRP · P> μPP · P (Equation 4)

ΜCRF · P ≧ μPP · P (Equation 5)

Further, in order for the retard roller 11 to rotate in the direction opposite to the feeding and to return the second sheet to the upstream side without double feeding, the distance between the retard roller 11 and the second sheet S Think that will not slip,

ΜCRP · P = μPP · P (Equation 6)

ΜCRP · P · r <M (Equation 7)

From equations 6 and 7, the following equation is established.

ΜPP · P · r <M (Equation 8)

It is necessary that the above-described three expressions, Expression 4, Expression 6, and Expression 8, be simultaneously satisfied.

In the retard method, each value is set in consideration of the above conditions and in consideration of the durability of the roller.

FIG. 5A shows driving signals for sheet feeding by the pickup roller 9, the feed roller 10, and the retard roller 11.

In FIG. 5, A is a start button, B is a pickup solenoid, and C is an ON signal of a feed roller clutch.

{Structure for Feeding Envelopes and the Like} The sheet feeding apparatus according to the present invention can set sheet type setting means so that even sheets having folded portions such as envelopes can be fed without jamming. The feeding time by the pickup roller 9 is changed in accordance with the sheet type set by the user. Next, the configuration will be described.

As shown in FIG. 6, a setting dial 60 for setting the sheet type and sheet size, which constitutes the sheet type setting means, is provided at the end of the sheet cassette 8 on the drawer side.

FIGS. 7A and 7B are detailed views of sheet type and sheet size setting means when the sheet cassette 8 is pulled out from the main body. FIG. (b) shows the side built in the cassette side.

As shown in FIG. 7 (b), the setting dial
A switch pressing disk 62 is coaxially attached to a dial shaft 61 integral with the dial 60, and is configured to be rotatable integrally with the dial 60. Further, as shown in FIG. 7A, a tact switch 63 is provided on the apparatus main body side.

Here, the relationship between the switch pressing disk 62 and the tact switch 63 will be described with reference to FIG. FIG.
(a) is a plan explanatory view of the setting means, (b) is a front sectional explanatory view, and (c) is a partial detailed view of the switch pressing disk 62 and the tact switch 63 as viewed along the broken line in FIG. 8 (b). FIG.

As can be seen from FIG. 8 (c), the switch pressing disk 62 is partially provided with a notch, and the tact switch 63 cannot be pressed at the notch. By shifting the position of the notch for each size indicated on the dial 60 and combining this disk 62, the CPU as the control means that controls the operation of the main body by changing the combination of the tact switch ON / OFF signal Let it.

In the case of envelopes, since the paper size varies widely, in this embodiment, the sheet type is set with the sheet size setting dial 60 as shown in FIG. In the sequence, the sheet length is fixed (maximum value).

As described above, when the sheet type is set, the CPU detects this, and the movement of the pickup roller 9 at the time of sheet feeding is configured to be longer than that at the time of normal sheet feeding. .

In this embodiment, the pickup roller 9 is moved up and down a plurality of times in order to extend the feeding time. This operation will be described in detail. In FIG. 2, the pickup cam 30 is rotated by exciting the flapper solenoid 33 in conjunction with the feed start signal, the lift-up lever 29 swings, and the pickup roller shaft 9a is moved. The pickup roller 9 descends, and comes into contact with the sheet S to feed out the sheet S. Thereafter, the pickup roller 9 comes into contact with the sheet surface for a time determined by the shape and the angular velocity of the pickup cam 30, and rises away from the sheet surface.

At this time, when it is determined by the sheet type setting means that the sheet being fed is an envelope having the folded-back portion Sa, the pickup roller 9 is raised by a normal operation, and a predetermined time is set. Thereafter, by exciting the flapper solenoid 33 again, the pickup cam 30 is rotated, the lift-up lever 29 is swung to lower the pickup roller shaft 9a, and the pickup roller 9 is brought into contact with the surface of the envelope having no folded portion. To push the envelope.

Thereafter, the pickup roller 9 comes into contact with the surface of the envelope having no folded portion for a time determined by the shape and the angular velocity of the pickup cam 30, and moves up and away from the sheet surface. Thus, the feeding time by the pickup roller 9 becomes longer than that in the case of a normal sheet.

During this time, the drive of the feed roller 10 and the retard roller 11 is continued by the drive source described above. FIG. 5B shows the driving signals of the respective elements at this time.

Next, the relationship of the conveying force will be described with reference to FIG. In FIG. 9B, μARP is the coefficient of friction between the sheet and the pickup roller 9, and W is the weight of the pickup roller 9. At this time, the following equation is established.

ΜCRP · P · r = M (Equation 9)

ΜPP · P + μARP · W> μCRP · P (Equation 10)

From the above equations (9) and (10),

ΜPP · P + μAPR · P> M · r (Equation 11)

By satisfying the above formula 11, it is possible to prevent only the folded portion of the envelope from being separated and conveyed.

Further, it is known from experiments that there is some time before the envelope is buckled by the separating means, depending on the strength of the stiffness of the envelope. It is enough to prevent buckling.

[Second Embodiment] Next, as a second embodiment, an example in which the sheet feeding apparatus according to the present invention is applied to a copying machine will be described. The members having the same functions as those of the first embodiment are denoted by the same reference numerals.

FIG. 10 is an external view of the multifunction copier. In FIG. 10, reference numeral 64 denotes an apparatus main body, 65 denotes a manual feed unit, 66 denotes an operation unit, 67 denotes an LCD touch panel, 68 denotes a start button, and 69 denotes a start button. It is a ten-key button.

Next, the operation of the pickup roller 9 provided in the manual feed unit 65 will be described.

FIG. 11 is an explanatory view of a central section of the manual feed unit, and FIG. 12 is an explanatory view of the manual feed unit and the back surface. In these figures, reference numeral 70 denotes a support plate for supporting the pickup roller 9, reference numeral 71 denotes a sheet stopper for abutting when setting a sheet, and reference numeral 72 denotes a feed roller.
A leading edge detection sensor detects that the leading edge of the sheet has passed through the nip between 10 and the retard roller 11, a trailing edge detecting sensor 73 detects that the trailing edge of the sheet has passed, and 74 detects that a sheet has been set on the tray. It is a set sensor to perform.

Reference numeral 75 denotes a side regulating plate for regulating both ends in the width direction of the sheet S, reference numeral 76 denotes a tray cover, and reference numeral 77 denotes a tray main body. Further, reference numeral 78 denotes a latching type solenoid which operates by projecting and attracting the iron core, and particularly by passing reverse currents. 79 is a link for transmitting the movement of the iron core of the solenoid, and 80 is a pickup arm for moving the support plate 70 of the pickup roller 9 up and down in response to the movement of the link 79.

In the above-described configuration, in the normal sheet feeding mode, when it is detected as a signal that the user has pressed the start button 68, the solenoid 78 shown in FIG.
Current is passed through the core and the iron core protrudes. Then, the link 79 moves rightward in FIG. 12, rotates the pickup arm 80 around the center of rotation, and moves the arm 80 to the position indicated by the broken line. As a result, the protruding portion of the arm tip that protrudes toward the far side of the drawing (not shown) is separated from the support plate 70 (see FIG. 11). Then, the support plate 70 attached so that the feed roller shaft 10a becomes the center of rotation rotates together with the pickup roller 9 in the direction of the arrow A in FIG. 11, and the pickup roller 9 comes into contact with the sheet surface. Then, the feeding clutch is turned on, and each roller rotates in the feeding direction.

Here, when the sensor detection sensor 72 is turned on, a current reverse to that at the time of feeding is supplied to the solenoid 78, and the iron core is attracted. As a result, the link 79 moves to the left in FIG. 12, rotates the pickup arm 80 around the center of rotation, and returns the arm 80 to the position indicated by the solid line. Then, the protruding portion of the arm tip protruding toward the far side of the drawing (not shown) pushes up the support plate 70 so that the feed roller shaft 10a becomes the center of rotation, and the pickup roller 9 is separated from the upper surface of the sheet.

The three rollers continue to rotate until the signal of the leading edge detection sensor 72 turns off. Further, when the number of sheets fed is large, the feeding of the second sheet is started when the signal of the sheet rear end detection sensor 73 is turned off, and the above-described operation is repeated thereafter.

The signal flow of these operations is shown in FIG.
13 (a), A is a start button signal, B is a pickup solenoid protrusion signal, C is a pickup solenoid suction signal, D is a feed clutch ON signal, E is a leading edge detection sensor signal, and F is a sheet trailing edge. This is a signal of the detection sensor 73. The value L shown therein indicates the time during which the pickup roller 9 is feeding the sheet in contact with the upper surface of the sheet, and is normally set to a constant value when the sheet is fed.

Next, the operation for feeding an envelope having a folded portion will be described. When sending an envelope, in the present embodiment, the user sets to send an envelope using the touch panel 67.

FIG. 14A shows a panel display at the time of this setting. Reference numeral 81 denotes an envelope mode selection switch as signal output means. When the user selects this mode, the display
As shown in FIG. 14 (b), the user operates the ten-key button 69 according to the displayed instruction to input the length of the folded portion and the length of the envelope. The feed time by the pickup roller 9 is set by this input value, and the feed time can be appropriately set by changing this value (time setting means). Needless to say, in the input, when the value of the length of the folded portion is longer than the value of the length of the envelope, the setting must be performed again.

After that, the movement after the start button 68 is pressed to start feeding is the same except that the time during which the pickup roller 9 is in contact with the upper surface of the sheet is different.

FIG. 13B shows the operation at that time.
LL shown in this figure indicates the time during which the pickup roller 9 is in contact with the upper surface of the sheet and feeds the sheet. If the length input by the user from the touch panel 67 is MM and the feeding speed is V, LL is LL.
= MM / V. That is, the user can freely set the feeding time from the touch panel 67.

As in this embodiment, when the envelope is fed, the feeding time by the pickup roller 9 is set to be longer than that in the case where the normal sheet is fed, according to the value appropriately set by the user. Also, as in the above-described embodiment,
When the folded portion is nipped by the separating means, the feeding force increases, so that a jam or the like does not occur.

In the above-described embodiment, the image forming apparatus is exemplified as the apparatus using the sheet feeding apparatus. However, the apparatus for feeding the sheet is not limited to the image forming apparatus.
For example, the present invention can be applied to an image reading apparatus for automatically feeding a sheet and reading an image.

[0095]

According to the present invention, as described above, when a sheet having a folded portion such as an envelope is fed, the sheet feeding time of the feeding means is increased, so that the folded portion is connected to the separating means. When the sheet is located, the sheet feeding force is increased, and even if the sheet is an envelope or the like, the sheet can be separated and fed stably without buckling.

Also, by configuring the user to be able to appropriately set the sheet feeding time, various sheets can be reliably separated and fed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an overall configuration of an image forming apparatus using a sheet feeding device.

FIG. 2 is a diagram illustrating a configuration of a sheet feeding apparatus.

FIG. 3 is an explanatory diagram of a configuration of a separating unit.

FIG. 4 is an explanatory diagram of a frictional force between a separating unit and a sheet when a normal sheet is fed.

FIG. 5 is an explanatory diagram of an up-down signal of a pickup roller.

FIG. 6 is an explanatory perspective view of a cassette provided with a sheet type setting dial.

FIG. 7 is an explanatory diagram of a configuration of a sheet type setting unit.

FIG. 8 is an explanatory diagram of a configuration of a sheet type setting unit.

FIG. 9 is an explanatory diagram of a frictional force between a separating unit and a sheet when feeding an envelope.

FIG. 10 is an external view of the multifunction copier.

FIG. 11 is a central sectional explanatory view of a manual feeding unit.

FIG. 12 is an explanatory diagram of a manual feed unit and a back surface.

FIG. 13 is an explanatory diagram of an up-down signal of a pickup roller.

FIG. 14 is an explanatory diagram of a touch panel.

[Explanation of symbols]

 A: Image forming apparatus B: Scanner section C: Image forming section D: Sheet feeding apparatus S: Sheet Sa: Folding section U1: Feeding unit U2: Feeding unit U3: Feeding unit 1: Scanning light source 2: Platen Glass 3 Document pressure plate 4 Mirror 5 Lens 6 Photoelectric conversion element 7 Laser scanner 8 Sheet cassette 8a Lower cassette 8b Upper cassette 9 Pickup roller 9a Pickup roller shaft 10 Feed roller shaft 10A 11… Retard roller 12… Transport roller 13… Transport roller 14… Registration roller 15… Photoconductor drum 16… Optical system 17… Developer 18… Transfer charger 19… Transport belt 20… Fixing device 21… Discharge roller 22… Tray 23 … Branch point 24… Double-sided tray 25… Sheet loading plate 26… Roller holder 28… Axis 29… lift-up lever -29a ... Spring 30 ... Pickup cam 31 ... Gear 32 ... Pickup gear 33 ... Solenoid 34 ... Motor 35 ... Gear 36 ... Lifter 37 ... Ratchet gear 38 ... Lift-up gear 39 ... Lift-up cam 40 ... Feeding claw 41 ... Shaft 42 ... Lock claw 43 ... Lifter trigger lever 44 ... Spring 45 ... One-way bearing 46 ... Pulley 47 ... Gear 48 ... Timing belt 49 ... Pulley 50 ... Retard roller drive shaft 51 ... Torque limiter 52 ... Coupling 53 ... Pressing arm 54 ... Pressing Roller 55… Coil spring 56… Retard adjustment arm 57… Axis 58… Retard roller bearing 59… Retard roller shaft 60… Setting dial 61… Dial shaft 62… Switch pressing disk 63… Tact switch (signal output means) 64… Device body 65… Manual feed unit 66 ... Operation unit 67 ... Touch panel 68 ... Start button 69 ... Numeric keypad 70 ... support plate 71 ... sheet stopper 72 ... leading edge detection sensor 73 ... rear edge detection sensor 74 ... set sensor 75 ... side regulating plate 76 ... tray lid 77 ... tray body 78 ... solenoid 79 ... link 80 ... pickup arm 81 ... envelope mode Selection switch (signal output means)

Claims (6)

[Claims] 1. A sheet feeding device for separating and feeding sheets, a feeding means for applying a feeding force to the sheets, and a sheet fed by the feeding means being separated into sheets one by one. Separation means comprising a feed rotator rotating in the sheet feeding direction and a retard rotator rotating in the sheet return direction, a type setting means for setting the type of sheet, and a sheet type. Control means for changing a sheet feeding time by said feeding means by means of the sheet feeding device. 2. The pick-up roller according to claim 1, wherein said feeding means is an up state when the sheet is not fed, and is a down-rotable pickup roller which rotates when the sheet is fed. 2. The sheet feeding device according to claim 1, wherein the feeding time is changed by performing the up-down operation twice or more. 3. The sheet feeding apparatus according to claim 1, further comprising time setting means for setting a sheet feeding time by said feeding means according to a type of the sheet. 4. The sheet feeding apparatus according to claim 3, wherein when feeding a sheet having a folded portion, a sheet feeding time by a feeding unit is changed according to a length of the folded portion. Sheet feeding device. 5. The apparatus according to claim 1, further comprising: signal output means for outputting a signal corresponding to the type of the sheet, wherein the control means controls based on a signal from the signal output means.
The sheet feeding device as described in the above. 6. An image forming apparatus for feeding a sheet to form an image, the sheet feeding apparatus according to claim 1, and forming an image on the fed sheet. An image forming apparatus comprising: