JPH11193135A - Sheet feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeding device capable of simplifying a weight balance adjustment and loading sheets to a maximum within limited space. SOLUTION: A sheet loading plate 5 loading sheets S is provided inside a sheet loading means 1 so that the plate 5 may be elevated and lowered. An elevating/lowering means 10 elevating/lowering this sheet loading plate 5 is arranged upstream of a sheet feeding direction from a center of gravity when the sheet loading plate 5 loads maximum loading size sheets. Further, the sheet loading plate 5 is horizontally held when sheets S are fed and the plate 5 is elevated and lowered by a holding means 15 arranged in the downstream of a sheet feeding direction from the elevating/lowering means 10 and at a location deviated from a feeding means 2A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for sequentially separating and feeding the uppermost sheets stacked and stored in sheet stacking means by feeding means, and more particularly to a sheet feeding device provided inside the sheet stacking means. The present invention relates to a lifting structure of a loading plate.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, there is provided a sheet feeding apparatus for sequentially feeding the uppermost sheet of a sheet such as a recording material or a document, which is stacked and stored in a sheet stacking means. Have.

FIG. 3 is a diagram showing the configuration of such a conventional sheet feeding apparatus. In FIG. 3, reference numeral 1 denotes a tray serving as sheet stacking means for stacking and storing a plurality of sheets S;
Is disposed above the tray 1 and feeds the uppermost sheet S1 of the sheets S stacked and stored in the tray 1 by air and feeds the sheet S1, and the blowing means 3 blows out separation air as shown by an arrow. This is a separating unit that separates the top sheet S1 from other sheets.

[0004] Reference numeral 4 denotes a frame of the tray 1 having an open upper surface. Inside the frame 4, a sheet stacking plate is provided so as to be able to move up and down. Here, this sheet loading plate 5
Two lifting wires 8 having one end fixed to the sheet stacking plate 5
a, 8b and two lifting wires 8c,
8d.

On the other hand, these lifting wires 8a, 8b, 8
c and 8d are wound around the pulleys 6 and 7 with the other ends fixed to the pulleys 6 and 7 which are rotated by a motor (not shown). When the sheet 7 rotates, the sheet stacking plate 5 moves up and down. The motor for lifting and lowering is driven and controlled based on a signal from a rear end detecting means 9 for detecting the rear end of the stacking sheet at a predetermined height at the rear end in the sheet feeding direction. .

Meanwhile, in the conventional tray 1 configured as described above, the height of the stacking surface of the sheet stacking plate 5 is set to 4
It is necessary to adjust the length of each of the lifting wires 8a, 8b, 8c, 8d. In addition, since the center of gravity changes depending on the size of the stacked sheets or the increase or decrease in the number of sheets, it is necessary to perform adjustment corresponding to the change in the center of gravity in advance. As such an adjusting method, there are a method of inclining the sheet stacking plate 5 and an adjusting method of balancing the weight of the sheet stacking plate 5 by weight or the like.

[0007]

However, in such a conventional sheet feeding apparatus, when the sheet feeding apparatus is provided in a limited space, the size of the sheet lifting / lowering means (structure However, there is a problem that the number of sheets to be loaded is limited by the height required for the operation.

As described above, when the tray 1 moves up and down in a direction perpendicular to the sheet feeding direction, the lifting wires 8a, 8b, 8c, 8d of the sheet stacking plate 5 and the pulleys 6, 7
Is intersected with the feeding means 2, the lifting means including the lifting wires 8a, 8b, 8c, 8d and the pulleys 6, 7 can be arranged at a position where the weight of the sheet stacking plate 5 is well balanced. However, there is a problem that it takes time to adjust the weight balance.

When the lifting wires 8a, 8b, 8c, 8d and the pulleys 6, 7 are arranged at positions not intersecting with the sheet feeding means 2, the lifting wires 8a, 8b, 8c, 8d and the sheet stacking plate 5 are fixed. The position is below the sheet stacking surface corresponding to the pulley diameter. Therefore, the sheet stacking plate 5
Is increased, and the sheet stacking amount (height L) decreases.

Therefore, the present invention has been made to solve such a conventional problem and can simplify the weight balance adjustment, and can maximally load the sheets in a limited space. It is an object of the present invention to provide a sheet feeding device that can perform the above-described operations.

[0011]

According to the present invention, there is provided a sheet for separating and feeding the uppermost sheet of the sheets stacked and stored in the sheet stacking means by a feeding means arranged above the sheet stacking means. In the sheet feeding device, the sheet stacking means is provided so as to be able to move up and down inside the sheet stacking means, and a sheet stacking plate for stacking the sheets, and a maximum stacking size of the sheet stacking plate. And a lifting means for raising and lowering the sheet stacking plate, and a sheet downstream of the lifting means in the sheet feeding direction and at a position deviated from the feeding means. Holding means for horizontally holding the sheet stacking plate.

Further, according to the present invention, the elevating means includes a pulley disposed at a bottom portion and an upper portion of the sheet stacking means, and a drive transmission member wound around the pulley and having both ends fixed to the sheet stacking plate. On the other hand, the holding means has a pulley disposed above the sheet stacking means, and a drive transmission member having one end fixed to the sheet stacking plate. The other end of the drive transmission member is fixed to the upper pulley of the elevating means so as to move by the same distance as the drive transmission member.

Further, as in the present invention, a sheet stacking plate for stacking sheets is provided in the sheet stacking means so as to be able to move up and down, and the elevating means for raising and lowering the sheet stacking plate is provided with a sheet stacking sheet having a maximum stacking size. It is arranged upstream of the center of gravity position in the sheet feeding direction. Further, the sheet stacking plate at the time of feeding and at the time of elevating and lowering is horizontally held by the holding means arranged at a position downstream of the elevating means in the sheet feeding direction and at a position deviated from the feeding means.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a sheet feeding apparatus according to the present invention, taken along a sheet feeding direction. In the figure, the same reference numerals as those in FIG. 3 indicate the same or corresponding parts.

In FIG. 1, reference numeral 2A denotes an air feeding means for sucking the uppermost sheet S1 of the sheets S stacked and stored on the tray 1, and the air feeding means 2A is hung between the pulleys 2a and 2b. The suction belt 2c and the suction duct 2d are provided, and the inside of the suction duct 2d is made to have a negative pressure by the suction blower 21, so that the uppermost sheet S
1 is adsorbed on the belt 2c and fed.

Reference numeral 3A denotes a separating means disposed on the leading end side of the tray 1 in the sheet feeding direction.
Shows the air from the blower 22 in the duct 3 as indicated by the arrow.
a from the nozzle 3b through the uppermost sheet S1
Is separated from other sheets. The separated sheet S <b> 1 is fed to the image forming apparatus main body by the conveying roller pair 23.

On the other hand, in FIG. 1, reference numeral 10 denotes an elevating means for elevating the sheet stacking plate 5;
0 is the sheet S stacked on the sheet stacking plate 5, the largest stack size sheet, that is, the sheet S having the longest length in the feeding direction, and the feeding direction upstream of the center of gravity of the sheet stacking plate 5. Located on the side.

The lifting means 10 is provided at the bottom of the frame 4 and is driven in the forward and reverse directions by a motor (not shown), an idler pulley 11 provided above the sheet stacking plate 5, and a sheet pulling means. Both ends 13a are fixed to the loading plate 5, and the driving pulley 12 and the idler pulley 11
And a rotation member 13 which is a drive transmission member such as a wire wound around the wire. The lifting means 10
Are also arranged on the opposite side.

By arranging the lifting / lowering means 10 upstream of the center of gravity in the maximum stacking sheet size in the feeding direction, a load is always applied to the leading end side in the feeding direction regardless of the sheet size and the number of stacked sheets. The weight balance of the sheet stacking plate 5 is not significantly changed. This simplifies the work of balance adjustment as compared with the related art.

On the other hand, in FIG. 1, reference numeral 15 denotes a holding means for holding the sheet stacking plate 5 horizontally during feeding and elevating, and the holding means 15 Air feeding means 2 on the downstream side in the feeding direction
A is arranged at a position deviated from A.

By providing the holding means 15 on the downstream side of the elevating means 10 in the sheet feeding direction,
Even if a load is applied to the leading end side in the feeding direction by the elevating means 10 provided at the above-described position, or even if the weight balance of the sheet loading plate 5 changes, the sheet loading plate 5 is always horizontal by the holding means 15. Can be kept in condition. Further, by keeping the sheet stacking plate 5 always horizontal by the holding means 15 in this manner, the lifting means 10 can be arranged at a position with good weight balance.

The holding means 15 has one end 17.
a, a transmission member 17 which is a drive transmission member such as a wire having the other end fixed to the idler pulley 11 of the lifting / lowering means 10, and an idler pulley 16.
And

Here, by fixing the other end of the transmission member 17 to the idler pulley 11 of the lifting / lowering means 10 as described above, when the idler pulley 11 of the lifting / lowering means 10 rotates, the transmission member 17 rotates the amount of rotation of the idler pulley 11. Only the length will change. That is, the transmitting member 17 moves by the same distance as the moving distance of the rotating member 13 of the lifting / lowering means 10.

By moving the transmitting member 17 by the same distance as the moving distance of the rotating member 13 of the elevating means 10, the sheet stacking plate 5 can be moved up and down while being held horizontally. . Further, the holding means 15
Since the transmission member 17 can be fixed to the upper end portion of the sheet stacking plate 5 by disposing the sheet stacking member at a position deviated from the air feeding means 2A, the thickness of the sheet stacking plate 5 can be reduced, which is limited. The maximum loading height (space) in the space can be obtained.

FIG. 2 is a diagram showing a configuration of a sheet feeding section of an image forming apparatus provided with a plurality of sheet feeding apparatuses according to the present embodiment, and two sheet feeding apparatuses in FIG. In the figure, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts.

In FIG. 1, reference numeral 30 denotes a frame of a sheet feeding unit, and 31 denotes a conveying unit for conveying a sheet fed from each sheet feeding device 2A to the image forming apparatus main body. In addition,
The sheet feeding device 2 </ b> A shown in the upper part of the drawing does not stack sheets, and shows a state where the sheet stacking plate 5 is lowered to the lowermost limit. Further, the sheet feeding device 2A shown in the lower part shows a state in which a plurality of sheets S are stacked and can be fed.

By the way, in the upper sheet feeding device 2A, L is the height at which sheets can be stacked, and 1 is the sheet stacking plate 5A.
Is the thickness. As shown in the figure, in the sheet feeding device 2A of the present invention, the thickness l of the sheet stacking plate 5 is set.
Can be reduced as compared with the related art (see FIG. 3), so that the stacked sheet height L can be increased.

It should be noted that a chain, a belt or the like can be used as a drive transmitting member constituting the rotating member 13 of the elevating means 10 and the transmitting member 17 of the holding means 15 in addition to the wire.

[0030]

As described above, according to the present invention, the lifting means for lifting and lowering the sheet stacking plate is provided upstream of the center of gravity of the sheet stacking plate when the maximum stacking sheet size is stacked, in the sheet feeding direction. Weight balance adjustment can be simplified. Also, by arranging the holding means at a position downstream of the sheet feeding direction from the elevating means and at a position deviated from the feeding means, the sheet stacking plate at the time of feeding and elevating the sheet stacking sheet regardless of the number of sheets loaded and the size of the sheet. It is possible to always keep the level and to load the sheets to the maximum in the limited space.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a sheet feeding apparatus according to the present invention, taken along a sheet feeding direction.

FIG. 2 is a diagram illustrating a configuration of a sheet feeding unit of an image forming apparatus including a plurality of the sheet feeding devices.

FIG. 3 is a cross-sectional view of a conventional sheet feeding apparatus taken along a sheet feeding direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet loading means 2, 2A feeding device (feeding means) 3 Separation means 4 Frame 5 Sheet loading plate 10 Elevating means 11 Idler pulley 12 Drive pulley 13 Rotating member 15 Holding means 16 Idler pulley 17 Transmission member

Claims (2)

[Claims] 1. A sheet feeding device for separating and feeding the uppermost sheet of sheets stacked and stored in a sheet stacking unit by a feeding unit disposed above the sheet stacking unit, wherein the sheet stacking unit A sheet stacking plate on which the sheets are stacked, and a sheet stacking plate on which the sheets are stacked, and the sheet stacking plate is disposed upstream of a center of gravity of the sheet stacking plate at the time of sheet stacking, and the sheet Lifting means for raising and lowering the stacking plate, and a sheet feeding direction downstream from the lifting and lowering means, and arranged at a position deviated from the feeding means, and at the time of feeding and lifting and lowering the sheet stacking plate horizontally A sheet feeding device, comprising: holding means for holding. The lifting means has a pulley disposed on the bottom and above the sheet stacking means, and a drive transmission member wound around the pulley and having both ends fixed to the sheet stacking plate. The holding means has a pulley disposed above the sheet stacking means, and a drive transmission member having one end fixed to the sheet stacking plate. When the drive transmission member is moved up and down, the drive transmission member of the elevating means is moved. 2. The sheet feeding device according to claim 1, wherein the other end of the drive transmission member is fixed to an upper pulley of the lifting / lowering means so as to move by the same distance as.