JP3482096B2 - Air suction type paper feeder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an air suction type paper feeding device provided in an image forming apparatus such as an electrostatic photocopier.

[0002]

2. Description of the Related Art An air suction type sheet feeding device in which an air stream is blown to stacked sheets of paper, the upper layer of paper is floated and separated, and the uppermost sheet of paper is sucked and conveyed by a vacuum suction means is known. It is described in JP-A-5-286596.

In this apparatus, a vertically movable pressing member is arranged between the feeding stretching belt and the uppermost sheet, and the uppermost sheet and the sheet below it are arranged by this pressing member. Therefore, the air flow blown from the front is blocked, and the air is expanded to surely separate the two sheets.

[0004]

However, even when the pressing member is provided as in the above-described conventional apparatus, the rear end aligning plate of the paper can be separately adjusted in position in the front and rear direction in order to align the rear ends of the paper. Therefore, there is a problem in that the space of the device is restricted, the degree of freedom in designing the device is reduced, the number of parts is increased, and the cost is increased.

The present invention has been made in view of such circumstances.
It is an object of the present invention to provide an air suction type paper feeding device which can be used for both aligning the trailing edge of a sheet and pressing the sheet with a simple structure.

[0006]

The present invention comprises means for solving the above-mentioned problems as follows. That is, an air flow is blown to the front end of the upper-layer paper stacked on the paper table by the blowing means to float the paper, and the uppermost paper is sucked and conveyed by the suction means. For air suction type paper feeding device of image forming device
There are reverses at the upper end of the use <br/> paper rear-end aligning plate an air flow blown by the blowing means, be directed downwardly
So that the paper can be placed upright on the rear of the paper stand.
The upper edge of the edge alignment plate is curved or bent toward the paper feed direction.
It is characterized in that it is formed in a shape .

[0007] the rear end of the contact with the top layer of the sheet is reversed along the curved surface or the bent surface air flow blown into the upper portion of the stacked sheets are the trailing edge of the sheet aligning plate in the sheet loading table on Is pressed to inflate the air between the uppermost sheet and the sheet below it, so that the sheets are effectively separated and double feeding is prevented.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an air suction type sheet feeding device of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view of an air suction type paper feeding device, and FIG. 2 is an enlarged view of a main part. In these drawings, reference numeral 1 is a paper tray which is operated to move up and down, 2 is a blowing means, 3 is a paper conveying means, 4 Is a suction means provided inside the paper conveying means 3, and a paper rear end aligning plate 5 for aligning the rear end of the paper P stands upright at the rear of the paper table 1 so as to be slidable in the paper feeding direction. It is set up.

The upper end of the sheet trailing edge aligning plate 5 is inclined toward the sheet feeding direction, and the leading end thereof is formed in a curved shape, and the air blown onto the upper layer portion of the sheet P by the blowing means 2 is blown. The flow comes into contact with the sheet trailing edge aligning plate 5, is reversed from the inclined surface 51 along the curved surface 52, and is discharged downward.
The upper surface of the rear part of the paper P is pressed down. Therefore, the uppermost paper P
The air expands between the sheet P and the sheet P below the sheet P, and the sheet P is effectively separated and double feeding is prevented.

The lower part of the sheet rear end aligning plate 5 is the main body 100 of the apparatus.
Guided by the guide member provided on the bottom of the
It can be fixed at a position corresponding to the size of the paper P, and has a rectangular opening 1a formed at the rear of the paper tray 1.
(See FIG. 3), so that the rear end of the upper layer portion of the sheet P on the sheet mounting table 1 raised to the sheet feeding position comes into contact with the inclined surface 51 and is pushed slightly forward. The height is set to.

At the time when the sheets P are initially stacked and placed on the sheet tray 1 (see the chain double-dashed line in FIG. 1) located at the lower sheet replenishment position, they are then transferred to the vertical surface 53 of the sheet trailing edge aligning plate 5. Although the edges are in contact with each other and are vertically stacked, when the paper tray 1 is lifted upward at the start of the paper feeding operation, the rear edge of the paper P in the upper layer portion is the above-mentioned. Thus, the sheet P of the upper layer portion is pushed out to the front a little as it abuts the inclined surface 51 and is enlarged and shown in FIG.

As described above, in the state in which the sheets P are stacked slightly diagonally to the front, the air flow from the spraying means 2 easily enters between the sheets P and P, and the separation between the sheets P and P is effectively performed. , the uppermost sheet P not only separation of the sheet P beneath it than because of a state paper P also play or <br/> previously been fully below, the aforementioned hold-down operation Together, the prevention of double feeding at the time of feeding becomes reliable.

The curved surface 52 formed on the upper end portion of the sheet rear end aligning plate 5 may be formed so as to direct the air flow downward, and may be formed in a bent shape. Further, it is preferable that the inclined surface 51 is formed so as to push out the upper layer portion of the sheet P slightly obliquely forward as shown in the figure, but it may be connected to the curved surface 52 from the vertical surface 53. The upper end may be formed in a curved shape or an inclined shape so that the air flow is blown downward from the upper end of the sheet rear end aligning plate 5 and the rear part of the sheet P is pressed.

The blowing means 2 described above has a blower 8 for generating an air flow at one end of a duct 7 having a rectangular cross section.
Are connected (see FIG. 3), the duct 7 is fixedly arranged at a position along the front surface of the paper tray 1 at the uppermost position, and the spray ports 6, ... Are opened on the inner wall surface thereof. At the same time, the upper wall is provided with blow-up ports 9, ... For preventing double feed, and the other ends are closed.

On the other hand, the paper tray 1 is provided with a winding electric mechanism 10
4 (see FIG. 4), the sheet P is automatically moved up and down according to the feeding state (remaining amount of sheets), and the uppermost sheet P is always held at the height position corresponding to the blowing ports 6, .... It The position control is performed by detecting the height position of the uppermost sheet P by the sensor 11
It is performed by controlling and driving the drive source based on the detection signal. In addition, the above-mentioned sensor 11
May be a contact type or a non-contact type, and its installation position may be appropriately selected as long as it can detect the uppermost layer of the paper P, and the installation position is provided in the front part of the paper tray 1. May be.

The electric winding mechanism 10 comprises a pulley 13 connected to a drive source, driven pulleys 14 to 17, tension pulleys 18 and 19, and an endless wire 20 wound around the endless wire 20. Are fixed to the paper tray 1 by brackets 21 and 22,
The sheet tray 1 is sequentially moved from the lowermost position (not shown) to the uppermost position (see FIG. 1) corresponding to the spray port 6 through the intermediate position shown in FIG. It is like this. It should be noted that instead of the winding electric mechanism 10, for example, an electric screw may be used to move and operate the paper tray 1.

The sheet conveying means 3 includes a belt 33 having a hole wound between a driving pulley 31 and a driven pulley 32,
The suction means 4 is provided inside the suction means 4, and the suction box 34 is connected to a suction pump 34 serving as a suction source, and the suction box 4 is opened from the openings 36 and 37 formed in the lower portion of the vacuum box 35. The air is sucked up, and the paper P is vacuum-adsorbed on the bottom surface of the belt 33 with holes.

As described above, the upper layer portion of the sheet P stacked on the sheet table 1 at the sheet feeding position is handled so as to be easily attracted by vacuum, and the rear portion of the uppermost sheet P is disposed. Since the air that is pressed down by the downward air flow and blows into the space between the next sheet of paper P expands and the two sheets of paper P are separated, a separate sheet pressing member is not required. On the other hand, in the process in which the adsorbed paper P is conveyed, an air curtain is formed by the air flow blown up from the blowing ports 9 ,.
The leading edge of the paper P below the vacuum-adsorbed paper P is prevented from advancing by the air curtain, and more reliable double feed prevention is achieved in combination with the effect of the above-described judgment.

[0019]

As described above, according to the air suction type sheet feeding device of the present invention, the upper end portion of the sheet trailing edge aligning plate erected on the rear portion of the sheet loading table is blown by the blowing means.
Invert the generated airflow at the upper edge of the paper trailing edge alignment plate
As can be directed to, toward the sheet feeding direction is formed in a curved shape or bent structure, air flow blown by the blowing means is reversed at the upper end of the paper rear-end aligning plate, sheet feeding appropriate position Since the upper surface of the uppermost sheet of paper is pressed down, a separate paper pressing member is not required, and the air expands between the uppermost sheet of paper and the paper below it, effectively separating the sheets and reducing the weight. Can be prevented from being sent.

Further, as described in claim 2, the trailing edge of the sheet is aligned.
By tilting the upper edge of the plate toward the paper feed direction,
The paper tray is raised upward at the start of the paper feeding operation.
And the trailing edge of the upper layer of paper touches the inclined surface as described above.
Abutting, as shown in the enlarged view of FIG.
The paper is pushed slightly forward. like this
In the state that the sheets are stacked diagonally forward,
The air flow from the spraying means becomes easier to enter and
Is effectively used for the uppermost paper and
Not only separate from the paper but also the paper below it in advance.
Since it is in a state of being separated by the minute,
Combined with operation, it is possible to prevent double feeding during paper feeding.
Will be

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an air suction type sheet feeding device of the present invention.

FIG. 2 is an enlarged view of a main part of the sheet rear edge aligning plate.

FIG. 3 is a perspective explanatory view of the spraying unit and the paper tray.

FIG. 4 is a configuration diagram of the air suction type paper feeding device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Paper mounting base, 2 ... Spraying means, 4 ... Suction means, 5 ... Paper rear end alignment plate, P ... Paper.

Claims (2)

(57) [Claims] 1. An air flow is blown by a blowing unit to a front end of a sheet of an upper layer stacked on a sheet table to float the sheet, and a sheet of the uppermost layer is sucked and conveyed by a suction unit. as in the in had us an air suction type paper feeding apparatus of an image forming apparatus, is reversed at the upper end of the paper rear-end aligning plate an air flow blown by the blowing means, downward direction
Stand upright at the rear of the paper stand so that
The trailing edge of the trailing edge of the paper is curved toward the paper feed direction.
Alternatively , the air suction type paper feeding device is formed in a bent shape . 2. The top edge of the paper trailing edge alignment plate
The spraying means is inclined toward
The air flow blown by the upper edge of the paper rear edge alignment plate.
Paper feed direction so you can flip it over and face it downwards
The curved shape or the bent shape is formed toward the
Air suction type paper feeder described.