JP2001302005A - Sheet feeder and image forming device having the same device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate separation of sheets even of a thin type. SOLUTION: A sheet feeder 240 comprises a sheet stacking means 22 on which sheets are stacked, a sheet feeding means 16 for feeding the sheets from the sheet stacking means, and a plurality of slanted members 11 to 13 disposed along the downstream edges of the sheets stacked on the sheet stacking means in order to separate the sheets one from the next when they are fed by the sheet feeding means. Out of the slanted members, a first slanted member 12 with a small feed resistance is opposed to the middle portion of the downstream edges of the sheets, and second slanted members 11 and 13 with a large feed resistance are spaced outward from the first slanted member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a sheet feeding apparatus for feeding sheets, and an image forming apparatus such as a copying machine, a printer, a facsimile, and a composite machine including the apparatus.

[0002]

2. Description of the Related Art Conventionally, in a sheet feeding apparatus provided in a main body of an image forming apparatus or the like and supplying the sheet into the main body, the sheets are separated one by one and are not fed (double feed) while the sheets are stacked. There is an inclined-separation type sheet feeding device provided with an inclined plate. Examples of the sheet include plain paper, a thin sheet of resin which is a substitute for plain paper, and cardboard.

FIG. 9 is a schematic vertical sectional view of a printer 130 which is an example of an image forming apparatus provided with a conventional sheet feeding device 140 in a main body 131.

[0004] The operation of the printer 130 will be described.

When a sheet is fed one by one from the sheet supply tray 101 by the sheet supply device 140 of the slope separation type,
The conveying roller 108 and the conveying roller 109 pinch the sheet while rotating, guide the sheet to the upper surface conveying guide 110 and the lower surface conveying guide 111, and send the sheet to the nip between the photosensitive drum 112 and the transfer roller 115. The photosensitive drum 112
The latent image formed by the laser scanner 114 on the photosensitive drum 112 is held by the toner cartridge 113 and is developed by the toner cartridge 113. When the sheet is fed into the nip between the photosensitive drum 112 and the transfer roller 15, the transfer roller 115
The toner image on the photosensitive drum 112 is transferred to a sheet, and the fixing device 116 fixes the toner image on the sheet. Finally, the discharge sheet roller pair 117, 118 discharges the sheet to the discharge sheet tray 119.

[0009] As shown in FIG. 9, the inclined-separation type sheet feeding device 140 includes a sheet feeding tray 101 having a horizontal sheet stacking surface 101 a for stacking sheets S in a bundle, and
A sheet supply roller 103 and the like are provided. At the downstream end of the sheet supply tray 101 where the sheet is fed, a slope plate 102 with which the downstream end of the sheet abuts is disposed at an angle θ with respect to the sheet stacking surface 101a. At the upstream end of the sheet supply tray 101, a rear end regulating member 120 that comes into contact with the rear end of the bundle of sheets S is provided so as to be adjustable in position.

FIG. 11 is a schematic plan view of the sheet feeding device 140 showing the arrangement of the inclined plate 102. The sheet supply roller 103 is rotatably provided integrally with a sheet supply roller gear 121 at a rotation end of a pair of sheet supply roller arms 105 rotatably provided on a sheet supply arm shaft 104. A drive gear 106 is fixed to the sheet supply arm shaft 104. One of a pair of sheet supply roller arms 105 has four idler gears 107.
A gear train including a, 107b, 107c, and 107d is rotatably provided. These four idler gears
The rotational force of the driving gear 106 is applied to the sheet supply roller gear 121.
Through the sheet supply roller 103.

FIG. 10 is an enlarged view of a contact portion between the sheet supply roller 103 and the sheet, and is a diagram used to explain the action of a force during the sheet supply operation.

Under the above configuration, the sheet is supplied as follows. The sheet supply arm shaft 104 receives a driving force from a controllable driving mechanism (not shown), and the driving mechanism controls start and stop of the sheet supply operation. That is, when the sheet supply is started, the sheet supply arm shaft 104 receives a driving force from a driving mechanism (not shown) and rotates. This rotational force is applied to the idler gears 107a, 107b, 1 in the sheet supply roller arm 105.
The power is transmitted to the sheet supply roller 103 via the sheet supply roller gear 121 and the sheet supply roller gears 107c and 107d. Thus, the sheet supply roller 103 starts rotating.

[0010] As shown in FIG.
03, the upper surface of the uppermost sheet S1 in the bundle of sheets S stacked on the sheet stacking surface 101a is pressed against the upper surface, so that when rotation starts, the uppermost sheet S1 is fed by frictional force. The force Fp acts. At the same time, the sheet S1 receives a frictional force (Fs12) with the sheet S2 immediately below the sheet S1 as a resistance. The sheet S1 receives the reaction force R1 from the slope plate 102, but is bent due to the force relationship between the reaction force R1 and the feeding force Fp. The sheet S1 advances while being curved on the slope plate 102 with the downstream end abutting against the slope plate 102. The sheet S2 does not advance due to the frictional force (Fs23) from the sheet S3 immediately below the sheet S2. As a result, double feeding of sheets does not normally occur.

As shown in FIG. 9, the sheet S1 is transported by a pair of conveying rollers 10.
The paper is further conveyed in the direction of the arrow by the rotation of 8, 109, and is fed into the nip between the photosensitive drum 112 and the transfer roller 115. Thereafter, as described in the description of the operation of the printer, the sheet is transferred with the toner image, fixed, and finally discharged onto the discharge sheet tray 119 and stacked.

[0012]

However, in the conventional sheet feeding apparatus 140, in order to prevent double feeding of a thin sheet (hereinafter, referred to as "thin sheet"), the angle θ of the slope plate 102 is set to 90 degrees. , The slope sheet 102 is set up, or the sheet supply position is approached to the slope sheet 102 to make it easier to sort thin sheets. However, when the slope plate 102 is set up, there is a problem that it becomes difficult to supply a thick sheet (hereinafter, referred to as a “thick sheet”).

Therefore, when the angle θ of the slope plate 102 is increased and the slope plate 102 is laid down, the thick sheet can be easily separated, and the thick sheet can be supplied while preventing the double feed of the thick sheet. However, it becomes difficult to handle thin sheets,
There is a problem that it is difficult to supply thin sheets while preventing double feeding.

As described above, the conventional sheet feeding apparatus 140
It has been difficult to improve sheet handling and prevent double feeding of sheets, whether thin or thick.

(Object) A first object of the present invention is to provide a sheet feeding apparatus which can easily process a thin sheet.

A second object of the present invention is to provide a sheet feeding apparatus for reliably separating both sides of a downstream end of a sheet.

A third object of the present invention is to provide a sheet feeding apparatus in which the sheet feeding capacity is enhanced by adding a separating operation on both sides of the downstream end of the sheet to the conveying operation of the intermediate portion at the downstream end of the sheet. It is in.

A fourth object of the present invention is to provide a sheet feeding apparatus which is capable of performing a stable judgment even when the positions of the stacked sheets are somewhat irregular, and has an excellent judgment performance.

A fifth object of the present invention is to provide a sheet feeding apparatus capable of always performing a stable judgment even if the sheets have different sizes.

A sixth object of the present invention is to provide an image forming apparatus having a sheet feeding device having at least one of the above-mentioned sheet feeding devices in a main body.

[0021]

To achieve the above object, a sheet feeding apparatus according to the present invention comprises a sheet stacking means on which sheets are stacked, a sheet feeding means for feeding the sheets from the sheet stacking means, A plurality of slope members arranged along a downstream end of the sheets stacked on the sheet stacking unit and separating sheets fed by the sheet supply unit one by one; Of which
A first slope member having a small conveyance resistance is disposed at a position facing an intermediate portion of the downstream end of the sheet, and a second slope member having a large conveyance resistance is separated to the outside of the first slope member. It is arranged.

In the sheet feeding apparatus according to the present invention, the second
Are provided on both sides of the first slope member.

In the sheet feeding apparatus of the present invention, the first
A third slope member having a lower conveyance resistance than the second slope member is disposed between the second slope member and the second slope member.

In the sheet feeding apparatus according to the present invention, the second
Is opposed to a portion inside the corner of the downstream end of the sheet.

In the sheet feeding apparatus according to the present invention, the second
The slope member is opposed to an end of the downstream end of the sheet, and protrudes outward from a corner of the downstream end.

In the sheet feeding apparatus of the present invention, the second
Is located opposite to the corner of the downstream end of the sheet.

In the sheet feeding apparatus according to the present invention, the second
Are provided on a pair of width regulating members, at least one of which is capable of regulating the width of the sheet.

In order to achieve the above object, an image forming apparatus according to the present invention includes any one of the above-described sheet supply apparatuses, and image forming means for forming an image on a sheet supplied by the sheet supply apparatus. I have.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the accompanying drawings.

(Printer) First, the configuration of a printer, which is an example of an image forming apparatus in which the sheet feeding apparatus according to the embodiment of the present invention can be provided in the main body, will be described with reference to FIG. FIG. 8 shows a printer 230 including a sheet feeding device 240 according to a first embodiment, which will be described later, in a main body 231.
Instead of the sheet feeding device 240 of the embodiment, the sheet feeding devices 340, 440, 440, and 440 of the second, third, and fourth embodiments are used.
540 is also provided.

The sheet discharge portion of the sheet supply device 240 is conveyed by a driving roller (not shown). The conveying roller 24a is rotated by a driving force. A transfer roller 24b that rotates following the rotation of the transfer roller 24a is provided. By the rotation of the transport rollers 24a and the transport rollers 24b, the sheet is nipped and transported away from the sheet supply device 240. The upper surface conveyance guide 110 guides the upper surface of the sheet. The lower surface transport guide 111 guides the lower surface of the sheet. The toner cartridge 113 integrally holds the photosensitive drum 112 and an image developing unit (not shown). Laser scanner 114
Form a latent image on the photosensitive drum 112. The transfer roller 115 transfers the toner image formed by developing the latent image on the photosensitive drum 112 in the toner cartridge 113 from the photosensitive drum 112 to a sheet. The fixing device 116 fixes the toner image on the sheet. Discharge sheet roller pair 11
Numeral 7 conveys the sheet after fixing. The discharge sheet roller pair 118 discharges sheets to a discharge sheet tray 119 provided outside the printer 230.

The operation of the printer 230 will be described. The sheet supply device 240 removes the sheet from the sheet supply tray 22 by one.
When the sheets are fed out one by one, the transport rollers 24a and the transport rollers 24b
, The sheet is nipped while rotating, guided by the upper surface transport guide 110 and the lower surface transport guide 111, and fed into the nip between the photosensitive drum 112 and the transfer roller 115.
A latent image is formed on the photosensitive drum 112 by a laser scanner 114 and is developed by a toner cartridge 113. When the sheet is fed into the nip between the photosensitive drum 112 and the transfer roller 15, the transfer roller 115
Transfers the toner image on the photosensitive drum 112 to the sheet, and the fixing device 116 fixes the toner image on the sheet.
Finally, the discharge sheet roller pair 117, 118 discharges the sheet to the discharge sheet tray 119.

The printer 230 described above is provided with the sheet supply device 240 in the main body 231 that reliably supplies sheets one by one without double feeding, so that an image can be reliably formed on a sheet. it can.

(Sheet Feeding Apparatus) Each of the sheet feeding apparatuses according to the embodiments of the present invention has a slope plate for separating sheets one by one so as to prevent feeding (double feeding) with the sheets stacked. It is a sheet supply device of a slope separation type.

(Sheet Feeding Device of First Embodiment) FIG.
FIG. 3 is a schematic plan view of the sheet feeding device 240 according to the first embodiment. FIG. 2 is a front view of the sheet feeding device 240.

Sheet supply tray (sheet stacking means) 22
At the downstream end in the transport direction, a slope 21 including a plurality of slope plates 11, 12, and 13 having two types of transport resistance is disposed along the downstream end.
3, and further downstream of the transport direction, transport rollers 24a,
A conveying roller 24b is arranged, and a rear end regulating member 120 (see FIG. 8) for supporting the rear end of the sheet bundle is arranged at the upstream end in the conveying direction so as to be adjustable in position. At a position separated from the slope 21, a sheet supply arm shaft 3 receiving a rotational force from a drive device (not shown) is provided so as to extend in parallel with the slope 21 and to be rotatably supported by a fixing member (not shown). ing.

A drive gear 4 is provided integrally with the sheet supply arm shaft 3, and a pair of sheet supply arms 2 are provided rotatably. On one side of the pair of sheet supply arms 2, a series of gears 5, 6, 7, 8 are rotatably provided. A sheet supply shaft 10 integrally including the sheet supply roller 1 and the sheet supply roller gear 9 is rotatably provided on the rotation end side of the pair of sheet supply arms 2.

The sheet supply roller 1, the sheet supply arm 2, the sheet supply arm shaft 3, the driving gear 4, the idler gears 5, 6, 7, 8, the sheet supply roller gear 9, the sheet supply shaft 10 and the like are provided by a sheet supply mechanism ( Sheet feeding means) 1
6.

The sheet supply operation of the sheet supply device 240 will be described. When the sheet supply arm shaft 3 is rotated by a drive device (not shown), the drive gear 4 is also rotated. The drive gear 4 transmits a rotational force to the idler gear 5 that is meshing with the drive gear 4. The rotational force is transmitted to the sheet supply roller gear 9 via the idler gears 6, 7, and 8, and further transmitted from the sheet supply roller gear 9 to the sheet supply roller 1 via the sheet supply shaft 10. When the sheet supply roller 1 is
, The sheet S stacked on the sheet supply tray 22 is fed one by one from the uppermost sheet by rotating in the direction of the arrow.

The sheet S whose feeding has been started is fed to the end slope plate (second slope member) 11, the middle slope plate (first slope member) 12, and the end slope plate by the feeding force from the sheet feeding roller 1. It is brought into contact with a part slope plate (second slope member) 13. The intermediate slope plate 12 is disposed so as to face the intermediate portion Sb at the downstream end of the sheet S, and has a friction member 15 having a small conveyance resistance on its surface.
Is provided. End slope plate 11 and end slope plate 1 on both sides
Numeral 3 is arranged opposite to the end Sa of the downstream end of the sheet S and spaced apart on both sides of the intermediate slope plate 12, and a friction member 14 having a large conveyance resistance is provided on the surface.

For this reason, the conveyance resistance of the end portion Sa of the sheet S becomes larger than the conveyance resistance of the intermediate portion Sb, and the feeding operation proceeds in the central portion including the intermediate intermediate slope plate 12. At both ends of the sheet S, a “judgement operation” is performed.
As a result, of the stacked sheets S, only the uppermost one sheet is conveyed.

The conveyance resistance is the resistance of the sheet being conveyed from the slope plate, and is mainly caused by the magnitude of the friction coefficient. Further, when comparing the friction coefficients of the friction members having the same friction coefficient, the comparison can be made based on the magnitude of the surface roughness. This is because the sliding resistance between the edge of the sheet and the slope plate during sheet feeding is the main factor of the conveyance resistance,
This is because the rougher the surface, the more easily the edge of the sheet is caught by the slope plate, and the greater the resistance it receives.

In the "separation operation", the downstream ends of several sheets from the top at the end portion Sa of the sheet S abut against the slope and are caught downward, forming a lower curl curled downward in the initial stage of sheet supply. Further, as the conveyance of the sheet in the intermediate portion progresses, a series of operations in which only the uppermost sheet is uncurled and conveyed on the slope, and the remaining sheets S return to the original stacking position. To tell.

As described above, the sheet feeding device 240 according to the first embodiment includes the downstream end of the sheet among the plurality of inclined plates 11, 12, and 13 having two types of conveyance resistance determined by the surface roughness and the coefficient of friction. Outside the intermediate slope plate 12 having a small transport resistance disposed at a position facing the intermediate portion Sb, the end slope plates 11 having a greater transport resistance than the intermediate slope plate 12,
By arranging the sheets 13 apart from each other, it is possible to make use of the difference in resistance of the sheet from the slope plate, and to reliably perform the double feed, especially for a sheet that is difficult to separate such as a thin sheet. Can be prevented.

Further, the sheet supply device 240 according to the first embodiment includes an end portion Sa inside the corner Sc at the downstream end of the sheet.
Since the end slope plates 11 and 13 having a large conveyance resistance are provided, the sheet conveyance operation is added at the both ends of the sheet to the conveyance operation at the intermediate portion at the downstream end of the sheet, and the sheet supply capacity is increased. A stable feeding operation can always be performed.

(Sheet Feeding Apparatus of Second Embodiment) Second
The sheet feeding device 340 according to the embodiment will be described with reference to FIG.

FIG. 3 is a schematic plan view of a sheet feeding device 340 according to the second embodiment. 1 and 2, the same parts as those of the sheet feeding device 240 of the first embodiment are denoted by the same reference numerals, and the description of the parts is partially omitted.

An intermediate slope plate (first slope member) 12 is disposed near the intermediate portion Sb of the sheet S and opposed to the sheet supply roller 1, and a range of a certain length (end portion) from both corners Sc of the sheet S is set. Corner slope plates (second slope members) 311 and 313 are arranged so that Sa) abuts. A friction member 14 having a large conveyance resistance is provided on the surfaces of the corner slope plates 311 and 313, and a friction member 15 having a small conveyance resistance is provided on the surface of the intermediate slope plate 12. Corner slope plates 311 and 3
13 protrudes outward from the corner Sc of the sheet S. The corner slope plates 311 and 313 and the middle slope plate 12 constitute an inclined portion 321 and constitute a part of a sheet supply tray (sheet stacking means) 322. Corner slope plate 31
1, 313 and the inclined portion 321 having the intermediate inclined plate 12
Are arranged along the downstream end of the sheet.

The operation of feeding the sheet S by the sheet feeding device 340 will be described. When the sheet supply roller 1 rotates, the downstream end of the sheet S comes into contact with the slope plates 311, 12, and 313, and similarly to the first embodiment, the intermediate slope plate 12 mainly performs the conveying function, and the corner slopes. The face plates 311 and 313 mainly fulfill the judgment function. Since both side edge lines Ss of the sheet are included in the slope range of the corner slope plates 311 and 313,
The end Sa including the corner Sc of the sheet S is surely formed on the corner slope plate 3.
11 and 313.

As a result, the sheet feeding device 3 of the present embodiment
In the case 40, the sorting operation described in the first embodiment can be performed with a smaller sheet supply force, and the occurrence rate of double feeding caused by a large sheet supply force can be suppressed.

Further, the sheet S is made up of the corner slope plates 311, 31.
Since the resistance force received from 3 is smaller than in the first embodiment, poor sheet supply of a thick sheet is less likely to occur.

In addition, the sheet supply device 34 of this embodiment
0 indicates that the downstream end of the sheet is in contact with the corner slope plates 311 and 313 having the highest end Sa transport resistance including the corner Sc of the downstream end of the sheet, and further, the corner slope plates 311 and 313
Is extended to the outside of both side end lines Ss (or corner Sc) of the sheet, so that even if the position of the sheet corner Sc of the sheet supply tray 322 varies,
The corners Sc of all the sheets come into contact with the corner slope plates 311 and 313, and the sheets can be reliably and stably blown to prevent double feeding.

(Sheet Feeding Device of Third Embodiment) Third
The sheet supply device 440 according to the embodiment will be described with reference to FIGS.

FIG. 4 is a schematic plan view of a sheet feeding device 440 according to the third embodiment. FIG. 5 is a front view of FIG. Note that the same parts as those of the sheet feeding apparatuses 240 and 340 of the first and second embodiments shown in FIGS. 1 to 3 are denoted by the same reference numerals, and the description of the parts is partially omitted.

The sheet feeding device 440 according to the third embodiment
Is capable of selectively loading sheets of different sizes. When the size of the sheet S changes, the position of the line Ss on both sides of the sheet also changes. The sheet supply tray (sheet stacking means) 422 has a pair of width regulating plates (width regulating members) 1 whose position can be adjusted in the width direction of the sheet according to the size of the sheet.
7 and 18. Corner slope plates (second slope plates) 411 and 413 are attached to the pair of width regulating plates 17 and 18. The corner slope plates 411 and 413 are configured such that ends Sa including the corner Sc of the sheet S are opposed to each other. That is, both side end lines Ss of the sheet fall within the range of the corner slope plates 411 and 413. The corner slope plates 411 and 413 and the middle slope plate 12 constitute a slope 421. The width regulating plates 17 and 18 are
One may be fixed and only the other may move. The inclined portion 421 having the corner inclined plates 411 and 413 and the intermediate inclined plate 12 is arranged along the downstream end of the sheet.

As a result, the sheet feeding device 440 of the third embodiment can adjust the width of the width regulating plate 17 according to the sheets S to be stacked.
18, the corner slope plates 411 and 413 also move, so that even if the size of the sheet S changes, the positional relationship of the corner slope plates 411 and 413 with respect to the corner Sc of the sheet S does not change. Regarding the sorting operation, the same performance as the sheet feeding device 340 of the second embodiment can be maintained.

(Sheet Feeding Device of Fourth Embodiment) Fourth Embodiment
The sheet supply device 540 according to the embodiment will be described with reference to FIG.

FIG. 6 is a schematic plan view of a sheet feeding device 540 according to the fourth embodiment, showing a form of a sheet immediately after sheet feeding. FIG. 7 is a view for explaining the features of the sheet feeding apparatus 540 according to the fourth embodiment.
FIG. 3 is a plan view showing a sheet form immediately after sheet supply by a sheet supply device 240 according to the first embodiment. Further, the sheet feeding device 2 according to the first to third embodiments shown in FIGS.
The same parts as those of 40, 340, and 440 are denoted by the same reference numerals, and the description of those parts is partially omitted.

A sheet feeding roller 1 is driven by a driving device (not shown).
When the driving force is transmitted to the sheet S, the sheet supply force is transmitted from the sheet supply roller 1 to the sheet S, and the sheet S is divided into an end slope plate (second slope member) 11 and an intermediate slope plate (first slope member). 12, abuts against an end slope plate (second slope member) 13. The relationship between the arrangement relationship of these slope plates 11, 12, and 13 and the conveyance resistance is determined by the sheet conveyance device 240 of the first embodiment.
Is the same as the relationship between the arrangement of the slope plates 11, 12, and 13 and the relationship between the conveyance resistance.

As shown in FIG. 7, since the intermediate slope plate 12 and the end slope plates 11 and 13 are spaced apart, the downstream end of the sheet S enters the gap and is shaped like a wave. Deform to. For this reason, the amount of penetration of the sheet S (the amount of plunge)
Increases, the contact portions between the end slope plates 11 and 13 and the sheet S become small, and a sufficient filtering effect may not be obtained (even in this case, a more sufficient filtering effect than in the related art may be obtained). Have been obtained.)

Therefore, as a method of narrowing the gaps formed on both sides of the intermediate slope plate 12, (1) the width of the intermediate slope plate 12 is increased, and (2) the end slope plates 11 and 13 are respectively connected to the intermediate slope plate 12. There are two alternatives: extend to the side. However, the method of (1) for widening the intermediate slope plate 12 cannot be adopted because if the width of the intermediate slope plate 12 is extremely wider than the width of the sheet supply roller 1, the sheet supply performance is reduced.
(2) The end slope plates 11 and 13 are respectively connected to the intermediate slope plate 12
The extension to the side cannot be adopted because the sheet S is too much caught on the end slope plates 11 and 13 and the sheet supply failure is likely to occur.

Accordingly, the sheet supply device 54 of the present embodiment
In FIG. 6, as shown in FIG. 6, the auxiliary slope plates 19, 20 located between the end slope plates 11, 13 and the intermediate slope plate 12 and near the end slope plates 11, 13 are fed. The tray (sheet stacking means) 522 is provided. A friction member 15 having a lower conveyance resistance than the friction member 14 is provided on the auxiliary slope plates 19 and 20. End slope plate 11, 1
3, the intermediate slope plate 12, and the auxiliary slope plates 19 and 20 form a slope portion 521 and form a part of the sheet supply tray 522. A slope portion 521 having end slope plates 11 and 13, an intermediate slope plate 12, and auxiliary slope plates 19 and 20.
Are arranged along the downstream end of the sheet.

In this way, the sheet feeding device 540 suppresses the entry (thrusting) of the sheet S into the gap formed on both sides of the intermediate slope plate 12 by the auxiliary slope plates 19 and 20, and the end slope plate 11 , 13 and the sheet S can be secured within a necessary range, and a sufficient filtering effect can be obtained. In addition, the portion indicated by the symbol Sd of the sheet S in FIG. 6 enters the gap appropriately (thrusts in).
This makes it easier for the sheet S to curl upward, thereby improving the sheet transportability.

Note that the end slope plates 11, 13, 411, 413 and the corner slope plates 311, 31 in the sheet feeding devices 240, 340, 440, 540 of the respective embodiments described above.
Numerals 3 each form a pair, and the friction members 14 having a large conveyance resistance are provided on both of the pairs, but they may be provided on only one of them. That is, on one side of the intermediate slope plate 12 having a small conveyance resistance, there is provided an end slope plate 11 having a large conveyance resistance.
411 and the corner slope plates 311 and 411 may be provided, and a new intermediate slope plate 12 having a small conveyance resistance may be provided on the other side. Also in this case, the sheet feeding device performs substantially the same operation as the case where the pair of inclined plates having a large conveyance resistance is provided, and the cost of the sheet feeding device can be further reduced.

Further, the end slope plates 11, 13, 411, 4
13, the middle slope plate 12, the auxiliary slope plates 19 and 20, and the corner slope plates 311, 313, 411 and 413 are such that the upper end is inclined in the sheet supply direction to the extent that the thick sheet can be fed. And

[0066]

According to the sheet feeding apparatus of the present invention, the sheet is separated by utilizing the difference in conveyance resistance received from the slope member. Can be prevented.

In the sheet feeding apparatus of the present invention, the sheet feeding capacity can be increased because the sheet feeding operation is performed at the both sides of the sheet in addition to the conveying operation at the center of the sheet.

In the sheet feeding apparatus according to the present invention, since the second slope member is extended to the outside of the corner of the sheet, even if the positions of both side edges of the sheet vary, both side edges of all sheets are on the second slope. By contacting the member, stable separating performance can be obtained.

In the sheet feeding apparatus of the present invention, since the second slope member is attached to the width regulating member, the second slope member always comes into contact with the sheet end even for different sheet sizes, and the separation is performed. It can be done reliably.

In the sheet feeding apparatus according to the present invention, the third slope member having a lower conveyance resistance than the second slope member is juxtaposed with a certain gap inside the second slope member. The gap between the first slope member and the second slope member is the third gap member.
By adjusting the amount of entry of the sheet into the gap and adjusting the two sides of the sheet to reliably contact the second inclined member, the sheet can be reliably separated.

The image forming apparatus of the present invention is provided with any one of the above-described sheet feeding devices for reliably performing sheet separation and preventing double feeding, so that an image can be reliably formed on a sheet.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a sheet feeding device according to a first embodiment of the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a schematic plan view of a sheet feeding device according to a second embodiment of the present invention.

FIG. 4 is a schematic plan view of a sheet feeding device according to a third embodiment of the present invention.

FIG. 5 is a front view of FIG. 4;

FIG. 6 is a schematic plan view of a sheet feeding device according to a fourth embodiment of the present invention.

FIG. 7 is a schematic plan view showing a sheet form immediately after sheet supply of a sheet supply apparatus of a first embodiment, for explaining features of the sheet supply apparatus of the fourth embodiment.

FIG. 8 is a schematic longitudinal sectional view of an image forming apparatus in which a sheet feeding device of the present invention can be provided in a main body.

FIG. 9 is a schematic longitudinal sectional view of an image forming apparatus including a conventional sheet feeding device in a main body.

FIG. 10 is an enlarged side view of a contact portion of a roller in a conventional sheet feeding apparatus, showing an action of force during a sheet feeding operation.

FIG. 11 is a schematic plan view of a conventional sheet feeding apparatus.

[Explanation of symbols]

S Sheet Sa End Sb Intermediate Sc Angle Ss Sheet Both Side End Lines 1 Sheet Supply Rollers 11, 13, 411, 413 End Slope (First Slope) 12 Intermediate Slope (Second Slope) 14 Transport Friction member having high resistance 15 Friction member having low conveyance resistance 16 Sheet feeding mechanism (sheet feeding means) 17, 18 Width regulating plate 19, 20 Auxiliary slope plate (third slope member) 22, 322, 422, 522 Sheet supply tray (Sheet stacking means) 240, 340, 440, 540 Sheet feeding device 230 Printer (image forming device) 231 Printer main body 311, 313, 411, 413 Corner slope plate (first slope portion)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Ryuichi Kojima 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 3F343 FA02 FB02 FC01 GA01 GB01 GC01 GD01 JD13 JD31 JD32 JD40

Claims (7)

[Claims] 1. A sheet stacking unit on which sheets are stacked, a sheet feeding unit for feeding the sheet from the sheet stacking unit, and a sheet stacking unit arranged along a downstream end of the sheet stacked on the sheet stacking unit, A plurality of slope members for separating the sheets fed by the sheet supply unit one by one, wherein the first slope member having a small conveyance resistance is provided between the downstream end of the sheet and the plurality of slope members. A sheet feeding device, wherein the second slope member having a large conveyance resistance is arranged at a position facing the portion, and the second slope member having a large conveyance resistance is arranged outside the first slope member. 2. The apparatus according to claim 1, wherein the second slope member is disposed on both sides of the first slope member.
A sheet feeding device according to claim 1. 3. A third slope member having a lower conveyance resistance than the second slope member is provided between the first slope member and the second slope member. Item 1
Or the sheet feeding device according to 2. 4. The sheet feeding apparatus according to claim 1, wherein the second slope member faces a portion inside a corner of a downstream end of the sheet. 5. The sheet according to claim 1, wherein the second slope member is opposed to an end of a downstream end of the sheet and protrudes outside a corner of the downstream end. The sheet feeding device according to the above. 6. The sheet processing apparatus according to claim 1, wherein the second slope member is provided on a pair of width regulating members movable at least one of which regulates the width of the sheet. A sheet feeding device according to any one of the preceding claims. 7. A sheet supply apparatus according to claim 1, further comprising: an image forming unit configured to form an image on a sheet supplied by the sheet supply apparatus. Image forming apparatus.