JPH101231A - Sheet feeding apparatus and image forming apparatus having the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In a sheet feeding device that sequentially separates and conveys a plurality of stacked sheets from the highest one by using air, regardless of the shape of the sheet such as curl. Good sheet feeding can be performed. A first sheet detecting means detects a height of a leading end of a top sheet of the sheets stacked on a sheet tray, and a second sheet detecting means detects a height of a central part. To detect. The sheet tray 11 is raised and tilted by the elevating mechanism 12 and the tilting mechanism 13 based on the outputs of the two detecting means 51 and 61, and the feeding position Ma corresponding to the shape of the sheet S such as curl is set. Regardless of the shape of the leading end of the sheet S, the position of the leading end of the sheet S can be kept constant with respect to the separating means 20 and the feeding means 30, and the curl portion can be made nearly horizontal by tilting. Feeding can be performed.

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 for separating and conveying, using air, sequentially from the highest one of a plurality of stacked sheets.

[0002]

2. Description of the Related Art In a sheet feeding apparatus used in an image forming apparatus such as a copying machine or a laser beam printer, a plurality of sheets such as recording materials and originals are stacked on a sheet tray (stacking member). It is known that the paper is fed in order from the upper one.

In such a sheet feeding apparatus, a roller sheet feeding apparatus which feeds a sheet on a sheet tray to a downstream side in a feeding direction by rotation of a sheet feeding roller is generally used.

Conventionally, in a roller sheet feeding apparatus, the paper feeding performance largely depends on the friction coefficient of the roller surface. For this reason, if the friction coefficient of the roller surface changes (generally becomes smaller) due to the aging of the roller material or the adhesion of paper powder or the like, defective feeding tends to occur. In addition, since the sheets to be used are various with various papers, films, etc.,
There is a drawback that these sheets cannot cope with various sheets having greatly different surface properties.

In order to solve the above-mentioned drawbacks, there has been proposed an air sheet feeding apparatus which sucks and conveys a sheet by using an air suction force. FIG. 4 shows a schematic configuration of a typical air sheet feeding apparatus that has been conventionally proposed.

The air sheet feeding apparatus 1 shown in FIG. 1 includes a stacking means 10 for sheets S, a separating means 20 disposed on the downstream side of the stacking means 10 (to the left in FIG. 1), and a stacking means. And a feeding unit 30 disposed above the front end side of the feeder 10.

The stacking means 10 has a sheet tray (stacking member) 11 for supporting a plurality of sheets S flatly in a stacked state, and an elevating mechanism 12 for elevating the sheet tray.

The separating means 20 has a floating nozzle 21 for blowing air to the leading end of the sheet S to float the sheet S, and a separating nozzle 22 for separating the uppermost sheet S from the next sheet S.

The feeding means 30 has a conveyor belt 33 wound around a downstream pulley 31 and an upstream pulley 32, and a suction duct 35 disposed inside the conveyor belt 33. A number of suction holes 33a are formed, and a suction opening 35a is formed in the suction duct 35 so as to face downward.

Further, above the rear end of the sheet tray 11, the uppermost sheet S of the plurality of sheets S placed on the sheet tray 11 is set at a feeding position Mo having a predetermined height. The sheet detecting means 41 is disposed in contact with the uppermost sheet S. In the vicinity of the separating means 20,
A guide plate 42 and a conveying roller pair 43 are arranged.

Next, a sheet feeding operation in the above-described sheet feeding apparatus will be described. First, air is blown from the levitating nozzle 21 to levitate several upper sheets S including the uppermost sheet S at the feeding position. Next, the uppermost sheet S is suctioned to the transport belt 32 by applying a negative pressure to the suction duct 35. The attracted sheet S is fed in the direction of the arrow Ks by the rotation of the conveyor belt 33 in the direction of the arrow R33, guided by the guide plate 39, and conveyed to the pair of pull-out rollers 40. At this time, by blowing air from the separation nozzle 22 to the leading end of the sheet being conveyed, the uppermost sheet S adsorbed on the conveyor belt 33 is separated from the next (second) sheet S.

As described above, when the sheets S on the sheet tray 11 are sequentially fed from the highest one, the height of the highest one of the sheets S on the sheet tray 11 decreases. This uppermost sheet S is sent to the sheet detecting means 4
1, the sheet tray 11 is raised by the lifting mechanism 12. After the sheet detecting means 41 detects again that the uppermost sheet S has been raised to the feeding position Mo, the lifting mechanism 12 is stopped.

[0013]

However, in the above-mentioned conventional sheet feeding apparatus, the feeding position Mo of the uppermost sheet is determined based on the detection of the sheet detecting means 41 abutting on the rear end of the sheet. When the sheet S on the sheet tray 11 is flat and flat, there is no problem. However, when the leading end of the sheet S is curled, the following problem occurs. .

In the sheet Sa curled upward (upwardly curled) as indicated by a broken line Sa in FIG. 4, the uppermost part of the curl of the sheet Sa is in contact with the transport belt 33. Therefore, when the uppermost sheet Sa is adsorbed on the conveyor belt 33 and conveyed, the second and subsequent sheets Sa are taken out, and a feeding failure such as a double feed or a jam occurs. In addition, the floating nozzle 2
The blowing of the air from 1 acts so as to press the sheet Sa against the conveying belt 33, so that the same feeding failure as described above occurs.

On the other hand, in the sheet Sb curled downward (down-curled) as indicated by a broken line Sb in FIG. 1, the central portion in the feeding direction of the sheet Sb is in contact with the transport belt 33. For this reason, a feeding failure similar to that of the above-described curled sheet Sa occurs. Further, in the sheet Sb having the lower curl, the floating due to the blowing of the air from the floating nozzle 21 becomes incomplete, and poor suction occurs.

Accordingly, the present invention provides a sheet feeding apparatus capable of smoothly feeding a sheet stacked on a stacking means even when the sheet is curled, and an image forming apparatus provided with the sheet feeding apparatus. It is intended to provide.

[0017]

The present invention according to the following claims 1 to 5 is a sheet feeding apparatus, wherein the present invention relates to a sheet feeding apparatus.
The invention according to claim 8 is an image forming apparatus.

According to a first aspect of the present invention, there is provided a stacking means for supporting a plurality of stacked sheets in a vertically movable manner and arranging a top sheet of the plurality of sheets at a predetermined feeding position. Separating means for blowing at least a top sheet of the plurality of sheets from the next sheet by blowing air to a leading end of the sheet on the stacking means in a feeding direction; A sheet feeding device that includes a feeding unit that feeds the top sheet in the horizontal direction while sucking the top sheet from above, and detects the height of the top sheet on the stacking unit on the leading end side in the feeding direction. A first sheet detection unit; and a second sheet detection unit configured to detect a height of a topmost sheet on the stacking unit on a rear end side in a feeding direction, wherein the stacking unit includes the first sheet detection unit. Sheet detection means and front The raising operation based on both the output of the second sheet detecting means is stopped, the arranged uppermost sheet in the feed position according to the shape, characterized in that.

According to a second aspect of the present invention, the first sheet detecting means is disposed at a position corresponding to a leading end of the sheet on the stacking means in a sheet feeding direction, and the second sheet detecting means is provided with: The sheet is arranged at a position corresponding to a central portion in the feeding direction of the sheet on the stacking means.

According to a third aspect of the present invention, the first sheet detecting means is disposed at a position corresponding to a leading end of a sheet on the stacking means in a sheet feeding direction, and the second sheet detecting means is provided with: The sheet is arranged at a position corresponding to a rear end in the feeding direction of the sheet on the stacking means.

According to a fourth aspect of the present invention, the stacking means includes a stacking member for stacking the plurality of sheets, an elevating mechanism for vertically moving the stacking member, and feeding the stacking member to the sheet. A tilting mechanism for tilting toward the direction,
Characterized by having In the invention according to claim 5, the stacking member has a swing center at a position corresponding to a leading end portion of the sheet on the stacking direction in the sheet feeding direction, and the tilting mechanism has a center on the swing center. The loading member is inclined by raising and lowering the rear end side of the loading member.

The present invention according to claim 6 (image forming apparatus)
According to another aspect of the present invention, there is provided a sheet feeding apparatus according to any one of the above-described aspects, and an image forming unit that forms an image based on a sheet fed by the sheet feeding apparatus.

According to a seventh aspect of the present invention, the sheet feeding device is characterized in that a recording material to be image-formed is a sheet related to the feeding.

According to an eighth aspect of the present invention, the sheet feeding apparatus is characterized in that a document serving as an original for image formation is a sheet related to the feeding.

[Operation] The main operation of the present invention based on the above structure (operation corresponding to claim 1) is as follows.

A plurality of stacked sheets are raised and lowered by the stacking means, and the uppermost sheet is arranged at a predetermined feeding position. The sheet having the uppermost sheet disposed at the feeding position is blown with air at the leading end in the feeding direction by the separating means. At least the uppermost sheet of the sheet to which air has been blown is floated and separated from the next sheet, and the uppermost sheet is sucked from above by the feeding means and fed in the lateral direction.

With the above operations alone, for example, if the leading end of the sheet on the stacking means is curled, as described above, the sheet may not be taken out, a double feed, a conveyance failure such as a jam, or a suction failure may occur. Occur.

Therefore, in the present invention, in addition to the above-described functions, the first sheet detecting means and the second sheet detecting means are provided to provide the following function, that is, the front end side of the uppermost sheet in the conveying direction. And the height at the rear end side in the transport direction is detected, and based on both outputs, the uppermost sheet is arranged at the feeding position according to the shape of the sheet. That is, for example, when the sheet on the stacking unit is curled, the uppermost sheet is not flat, but has gentle irregularities along the sheet feeding direction. By detecting the height of the uppermost sheet at two places, it is possible to detect the outline of the curl of the sheet (and, consequently, the shape of the sheet in the sheet feeding direction). It can be changed to something.

In particular, the first sheet detecting means may detect the height of the leading end of the uppermost sheet, which greatly affects the quality of sheet feeding (corresponding to claim 2).

The first sheet detecting means and the second
The leading end side in the feeding direction and the trailing end side in the feeding direction, which are arrangement positions with the sheet detection means, are not necessarily related to the fact that the length in the feeding direction varies depending on the sheet, and are not necessarily in the sheet conveying direction. It does not mean the front end side and the rear end side with respect to the center. That is, it shows the relative positional relationship between the first sheet detecting means and the second sheet detecting means, wherein the first sheet detecting means is located at the front end side with respect to the second sheet detecting means, and This means that the second sheet detecting means is located at the rear end side with respect to the first sheet detecting means.

Furthermore, if the first sheet detecting means and the second sheet detecting means are considered as a pair,
The uppermost sheet may be arranged at a position where the height difference (for example, curl amount) can be easily detected. This is because, for example, even if two sheet detecting means are arranged, if both are arranged at positions off the curl,
This is because the meaning of the individual arrangement is lost.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 is a longitudinal sectional view of a sheet feeding apparatus 1 according to the present invention along a sheet feeding direction. In FIG. 1, a plurality of sheets S such as papers having no curl are stacked in the stacking means 10 in a stacked state, and the sheet tray 11 is raised so that the uppermost sheet S of the plurality of sheets S has a predetermined height. When the sheet reaches the feeding position Mo, the sheet tray 11
1 shows the state when is stopped.

The sheet feeding apparatus 1 shown in FIG. 1 includes a stacking unit 10, a separating unit 20 disposed downstream of the stacking unit 10 (downstream in the sheet feeding direction), and a tip side of the stacking unit 10. (Refer to the left side portion of the loading means 10 in the figure) and a feeding means 30 disposed above. The description will be made in the following order.

The stacking means 10 includes a sheet tray 11 for stacking a plurality of stacked sheets S, a tilt mechanism 13 for tilting the sheet S, and a sheet tray 1 via the tilt mechanism 13.
And an elevating mechanism 12 for elevating and lowering 1.

The elevating mechanism 12 includes support frames 12b and 12 which are rotatably connected to each other about a center of rotation 12a.
c and the upper ends 12 of these support frames 12b and 12c.
b ₁ , 12c ₁ and a horizontal table 12d placed on the top of the sheet tray 11 described above.
A shaft 12e is provided as the center of swing of the shaft. Horizontal table 12d
Is driven by a driving means (not shown).
By changing the distance between the upper end portions 12b ₁ and 12c ₁ of 12c, the upper and lower portions are moved up and down in the arrow 12 direction. That is, the upper end 1
As the distance between 2b ₁ and 12c ₁ decreases,
On the contrary, it goes down by moving away.

The tilting mechanism 13 has an arm 13a mounted on the above-mentioned horizontal base 12d and a motor (drive source) 13b for driving the arm 13a. The arm 13a has its proximal end 1
3a by _a horizontal table 12d while being supported rotatably, the tip portion 13a ₂ is in contact with the lower surface of the substantially central portion of the sheet tray 11 described above. Rotation of the arm 13a in the arrow R13 direction via the motor 13b, the position of the distal end portion 13a ₂ of the arm 13a is increased, by which the sheet tray 11, about the axis 12e of the distal end portion, the rear end portion Rises in the direction of arrow K11. Arm 13a
Is rotated in the direction opposite to the arrow R13, the rear end of the sheet tray 11 descends in the direction opposite to the arrow K11.

The separating means 20 has a floating nozzle 21 for blowing air to the leading end of the sheet S to float the sheet S, and a separating nozzle 22 for separating the uppermost sheet S from the next sheet S.

The feeding means 30 has a conveyor belt 33 wound around a pulley 31 on the downstream side and a pulley 32 on the upstream side, and a suction duct 35 arranged inside the conveyor belt 33. , A large number of suction holes 33a (omitted in FIG. 1, FIG.
The suction duct 35 has a suction opening 35a directed downward.

A guide plate 42 for guiding the sheet S fed by the feeding means 30 and a pair of feeding rollers 43 for feeding the sheet S further downstream are arranged downstream of the feeding means 30. I have.

Further, the upper part of the sheet tray 11 and the upper part of the rear end of the sheet tray 11,
A first sheet detecting means 51 and a second sheet detecting means 52 are disposed above the front end side and the rear end side of the sheets S stacked on the sheet S1, respectively. Here, the leading end and the trailing end may be, for example, a position corresponding to the leading end of the sheets stacked on the sheet tray 11 and a position corresponding to substantially the center. First sheet detecting means 5
1 has a lever 52 and a photo sensor 53. The lever 52 is rotatably supported about a shaft 52a, and the leading end 52b lightly contacts the surface of the uppermost sheet S of the plurality of sheets S on the sheet tray 11,
The rear end 52c is detected by the photo sensor 53 described above. Here, the position of the contact point P where the distal end portion 52b of the lever 52 and the uppermost sheet S come into contact with each other may be directly above the shaft 12e of the distal end portion of the horizontal base 12d. The reason is that, as described above, the shaft 12e
This is because a contact point P is provided immediately above the point 1 when the contact point P is provided, and the height of the contact point P hardly changes due to the inclination of the sheet tray 11. That is, the first sheet detecting unit 51 keeps the position of the leading end of the uppermost sheet S constant irrespective of the inclination of the sheet tray 11 and, therefore, regardless of the shape of the sheet S such as curl. belongs to.

As shown in FIG. 6, the second sheet detecting means 61 has a lever 62 and photo sensors 63a and 63b. The lever 62 is rotatably supported about a shaft 62a, and the front end portion 62b lightly contacts the surface of the uppermost sheet S of the plurality of sheets S on the sheet tray 11, and the rear end. The parts 62c and 62d are detected by the photo sensors 63a and 63b, respectively. The photo sensor 63b detects that the position of the uppermost sheet S of the sheets S has been lowered with the sheet feeding operation of the sheets S on the sheet tray 11, and the above-described lifting mechanism 12
The sheet tray 11 is raised via 2d, whereby the uppermost sheet S on the sheet tray 11 can be arranged at a predetermined feeding position Mo. On the other hand, the photo sensor 6
3a is for stopping the driving of the tilting mechanism B,
It is detected that the topmost sheet on the sheet tray 11 has been raised by the tilt mechanism B, and the tilt mechanism is stopped.

FIG. 2 shows the sheet feeding apparatus 1 having the above-described configuration according to the present invention, in which the sheet S whose leading end is curled upward.
Is a diagram showing a state where the sheet tray 11 is stopped after the uppermost sheet S is placed at the feeding position Ma after the sheet tray 11 is moved up after being stacked on the sheet tray 11.

The operation of the sheet feeding apparatus 1 will be described with reference to FIG. Note that, in FIG. 2, only the reference numerals in FIG. 1 that are necessary for the description are shown.

First, a plurality of sheets S are placed in the sheet tray 1
1 will be described. At the time of loading the sheets S, the horizontal table 12d of the elevating mechanism 12 and the sheet tray 11 are lowered to the lowermost limit by the elevating mechanism 12, and
It is tilted by the tilting mechanism 13 and waits in a tilted posture with the rear end side down as shown by the broken line in FIG. In this state, the sheet S is placed on the sheet tray 11. Next, the sheet tray 11 is controlled by a command from an operation unit (not shown).
Is raised by the elevating mechanism 12 while maintaining the inclined posture (inclination angle). The sheets S stacked on the sheet tray 11 rise in an inclined posture in which the downstream side in the transport direction is lifted. Therefore, regardless of whether the leading end of the sheet S is curled upward (upward curl) or curled down (lower curl), the leading end on the downstream side in the transport direction is first sent to the first sheet detecting unit 51. Contact. When the first sheet detecting means 51 detects the uppermost sheet S, it stops the lifting of the sheet tray 11 by the lifting mechanism 12. At this time, since the uppermost sheet S has not yet contacted the second sheet detecting means 61, the lifting mechanism 1
The sheet tray 11 is moved in the direction of the arrow 11 by the tilting mechanism 13 at the same time when the sheet tray 11 is lifted and stopped by the step 2. The tilt mechanism 13 rotates the arm 13a in the direction of arrow R13 by the rotation of the motor 13b, and moves (ups) the sheet tray 11 in the direction of arrow 11 from the position indicated by the broken line. When the center of the uppermost sheet S on the sheet tray 11 in the transport direction is raised to the position indicated by the solid line in FIG. 2, this is detected by the second sheet detecting means 61, the motor 13b is stopped, and the sheet is tilted by the tilt mechanism 13. Tray 1
1 is stopped.

The uppermost sheet S out of the plurality of sheets S on the sheet tray 11 is fed by a predetermined feeding by the above-described lifting operation of the sheet tray 11 by the lifting mechanism 12 and the tilting operation by the tilting mechanism 13. It is arranged at the position Ma. Note that the feeding position Ma is a feeding position M suitable for feeding the uppermost sheet S whose leading end is curled up.
a, which is different from the feeding position Mo (see FIG. 1) for the flat sheet S without curl.

Next, as shown in FIG. 3, after the sheets S whose leading ends are curled downward are stacked on the sheet tray 11, the sheet tray 11 is raised to place the uppermost sheet S at the feeding position Mb. The state where the sheet tray 11 is stopped is shown. The uppermost sheet S curled downward is fed to the feeding position Mb.
The operation of the elevating mechanism 12, the inclining mechanism 13, the first sheet detecting means 51, the second sheet detecting means 61, and the like when disposing the sheet S is described above. Since it is the same as the case, the description is omitted.

The feeding position M of the uppermost sheet S shown in FIG.
b is the feeding position Mo shown in FIG. 1 or the feeding position M shown in FIG.
Different from a. That is, the optimum feeding position of the uppermost sheet S is determined when the sheet S is flat without curl as shown in FIG.
When there is an upper curl at the leading end of the sheet S, the feeding position Mo shown in FIG.
When there is a lower curl at the tip of the sheet, the feed position Mb shown in FIG. 3 is reached. In each case, the top sheet S
Are the same, and this position is detected by the sheet detecting means 41 and 51. This is because when feeding the uppermost sheet S, it is important to set the position of the leading end of the uppermost sheet S to an appropriate position.

Further, in the case of upper curl or lower curl,
The sheet tray 11 is tilted by the tilting mechanism 13 in accordance with each curl direction and curl amount to tilt the uppermost sheet S, which is set as the feeding position Ma, Mb.
Due to these inclinations, the curl at the leading end of the sheet S is brought closer to the horizontal as much as possible in both upper curl and lower curl. Thus, when air is blown from the floating nozzle 21 of the separation means 20 to the leading end of the sheet S, the air can easily enter between the sheets S, and the sheet S can be floated satisfactorily. it can.

As described above, the first sheet detecting means 51 and the second sheet detecting means 61 are provided on the leading end side and the trailing end side in the sheet conveying direction, respectively, and based on the outputs thereof. , The top sheet feeding position Mo, M
Since a and Mb are determined, even if the sheet S has an upper curl or a lower curl, even if the sheet S has
The leading end of the sheet S can be disposed at a favorable position with respect to the feeding means 30 and the sheet S, and the sheet S can be smoothly conveyed.

Further, since the sheet tray 11 is tilted by the tilting mechanism 13 so that the curl at the leading end of the sheet S approaches horizontal, the leading end of the sheet S is lifted by the floating nozzle 2.
1 can be arranged at a predetermined position, so that the air blowing action is constant even for the upper curled and lower curled sheets S.

Next, the sheet feeding apparatus 1 of the present invention described above.
An image forming apparatus (copier) having the configuration provided in the above will be described with reference to the cross-sectional view of FIG.

As shown in the figure, the image forming apparatus main body 200
Include a document table 206, a light source 207, an optical system 208,
A paper feed unit 209, an image forming unit (image forming unit) 202, and the like are arranged. The paper supply unit 209 includes a paper supply tray 210, a cassette 211, and a paper deck 213. The image forming unit 202 includes a photoconductor 214, a developing device 215 containing toner, a transfer charger 216, and a separation charger 2.
17, a cleaner 218, a primary charger 219, and the like. Downstream of the image forming unit 202, a conveying unit 220, a fixing device 204, a discharge roller 205, and the like are provided. In this image forming apparatus, the apparatus main body 200
When a paper feed signal is output from a control device (not shown) provided in the printer, the sheet S is fed from the paper feed tray 210, the cassette 211, or the paper deck 213. on the other hand,
The light emitted from the light source 207 to the original placed on the original placing table 206 and reflected is condensed on the photoconductor 214 via the optical system 208. The photoconductor 214 is charged in advance by a primary charger 219, and an electrostatic latent image is formed by light reflected from a document, and then a toner image is formed by a developing device 215.

The sheet S fed from the sheet feeding unit 209 is
The skew is corrected by the registration roller 201, and the skew is sent to the image forming unit 202 at a further adjusted timing. In the image forming unit 202, the toner image of the photoconductor 214 is transferred to the sheet S sent by the transfer charger 216, and the transferred sheet S is inverted by the separation charger 217 with the transfer charger 216. Photoreceptor 2 charged with polarity
14. Then, the separated sheet S is
The sheet is conveyed to the fixing device 204 by the conveying device 220, and the unfixed transferred image is permanently fixed by the fixing device 204. The sheet S on which the image has been fixed is discharged out of the apparatus main body 200 by the discharge roller 205.

The present invention is not limited to the above embodiment, but may be applied to, for example, an automatic document feeder (ADF) for automatically feeding a document. For example, as shown in FIG. 5, a document tray 300 on which a document is placed, a sheet feeding device 1 to which the present invention is applied, and a document tray The original sent from above 300 is placed on the original placing table 206.
And a light source 20 between the light source 20
And a discharge tray 30 on which a document whose image has been read by a document reading means including the optical system 208 and the like is stacked.
And 3 is roughly constituted.

[0055]

As described above, according to the present invention, in the sheet feeding apparatus for separating and conveying by using air sequentially from the highest one of a plurality of stacked sheets, The first sheet detecting means and the second sheet detecting means respectively detect the height of the front end side and the rear end side of the sheet in the conveying direction, and feed the sheet according to the sheet shape such as curl based on these outputs. The position can be set, that is, the position of the leading end of the sheet can be kept constant regardless of the curl or the like, so that the sheet can be favorably fed regardless of the shape of the sheet such as the curl. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a state of a sheet feeding apparatus when flat sheets are stacked.

FIG. 2 is a cross-sectional view illustrating a state of the sheet feeding apparatus when a sheet whose leading end is curled upward is stacked.

FIG. 3 is a cross-sectional view illustrating a state of the sheet feeding apparatus when a sheet whose leading end is curled downward is stacked.

FIG. 4 is a sectional view showing a conventional sheet feeding apparatus.

FIG. 5 is a longitudinal sectional view showing a schematic configuration of an image forming apparatus provided with a sheet feeding device.

FIG. 6 is a diagram illustrating a configuration of a second sheet detection unit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 sheet feeding device 10 stacking means 11 sheet tray 12 elevating mechanism 12a center of rotation 12b, 12c support frame 12d horizontal base 12e shaft 13 tilting mechanism 13a arm 13b motor 20 separating means 21 floating nozzle 22 separation nozzle 30 feeding means 31, 32 Pulley 33 Conveyor belt 35 Suction duct Mo Feeding position for flat sheet Ma Ma Feeding position for upper curl sheet Mb Feeding position for lower curl sheet S Sheet

Claims (8)

[Claims] A stacking means for supporting a plurality of stacked sheets in a vertically movable manner and arranging an uppermost sheet of the plurality of sheets at a predetermined feeding position; and a sheet on the stacking means. Blow air to the end in the feeding direction of
Separating means for floating at least the uppermost sheet of the plurality of sheets from the next sheet, and feeding means for feeding the uppermost sheet floated by the separating means from above while feeding the sheet horizontally. A first sheet detecting means for detecting the height of the top sheet on the stacking means on the leading end side in the feeding direction, and a sheet feeding apparatus for the highest sheet on the stacking means. A second sheet detecting unit that detects a height at a rear end side in a feeding direction, wherein the stacking unit is configured to output the first sheet detecting unit and the second sheet detecting unit based on both outputs of the first sheet detecting unit and the second sheet detecting unit. A sheet feeding device, comprising: stopping the ascent operation; and arranging the uppermost sheet at the feeding position according to the shape thereof. 2. The method according to claim 1, wherein the first sheet detecting unit is disposed at a position corresponding to a leading end of the sheet on the stacking unit in a feeding direction, and the second sheet detecting unit is configured to detect a position of the sheet on the stacking unit. The sheet feeding device according to claim 1, wherein the sheet feeding device is disposed at a position corresponding to a central portion in a feeding direction. 3. The sheet detecting device according to claim 1, wherein the first sheet detecting unit is disposed at a position corresponding to a leading end of the sheet on the stacking unit in a feeding direction. The sheet feeding device according to claim 1, wherein the sheet feeding device is disposed at a position corresponding to a rear end portion in a feeding direction. 4. A stacking member for stacking the plurality of sheets, a lifting mechanism for moving the stacking member in a vertical direction, and an inclination for tilting the stacking member in a sheet feeding direction. The sheet feeding device according to claim 1, further comprising: a mechanism. 5. The loading member has a swing center at a position corresponding to a leading end portion of a sheet on the loading member in a sheet feeding direction, and the tilting mechanism is configured to rotate the loading member around the swing center. The sheet feeding device according to claim 4, wherein the stacking member is inclined by raising and lowering a rear end side. 6. A sheet feeding device according to claim 1, further comprising: an image forming unit that forms an image based on the sheet fed by the sheet feeding device. An image forming apparatus comprising: 7. The image forming apparatus according to claim 6, wherein the sheet feeding device sets a recording material on which an image is to be formed as a sheet related to the feeding. 8. The image forming apparatus according to claim 6, wherein the sheet feeding device uses a document serving as an original for image formation as a sheet related to the feeding.