JPS61254439A - Sheet feeder - Google Patents

Abstract

PURPOSE:To accomplish sure separation of sheets to be fed by installing No.2 group of nozzles so that the air streams therefrom are concentrated, and thereby enhancing the separation efficiency of the uppermost lying sheet from the other. CONSTITUTION:The No.1 group of nozzles 15, 15 are oriented in parallel with the surface at the top of the sheets 2 stacked on a sheet feed tray 1, and air streams from these nozzles put the leading edges of the sheets 2 lying at the top afloat and separate these sheets from each other. Then the suction force of a blower 10 is transmitted to an attraction hole 7 through a vacuum box 8 so as to attract the uppermost sheet 2a to a transport belt 6 at its oversurface. The air streams a from No.2 group of nozzles 16a-16c jet out so as to be concentrated to one point, and the velocity is converted into pressure to generate a stagnation pressure. This will boost the pressure between the uppermost sheet 2a and its subsequent 2b to provide sure separation of the sheet 2a, 2b through the action of this pressure.

Description

[Detailed Description of the Invention] LLL! 201 Plate Stand 1 The present invention relates to a paper feeding device used in an image forming apparatus such as a copying machine, facsimile machine, or printer to feed a large number of stacked sheets one by one starting from the topmost sheet.

[Button I The above image forming device has an automatic system that stacks a large number of sheets of paper or manuscripts on which images are to be formed, and feeds them one by one into the device, starting with the topmost sheet of paper, as necessary. Although paper feeding devices are widely used, conventionally most of them have been designed to press a paper feeding roller against the uppermost paper surface and take out the paper by friction. However, such a paper feeding device is l1tl! , multiple sheets of paper may be taken out at the same time, paper may be soiled by the paper feed roller,
Alternatively, there have been problems such as a decrease in the coefficient of friction and the occurrence of misfeeds in which sheets are not ejected.

For this reason, a paper feeding device has been proposed in which the topmost paper is sucked and taken out using a conveyor belt having a large number of suction holes that apply negative pressure. The following paper feed devices are listed. This paper feeding device is equipped with an air nozzle that opens near the leading edge of a stack of papers (original documents), and uses the air ejected from the air nozzle to feed the topmost sheet of paper into a large number of paper sheets to which the negative pressure is applied. It has a structure in which it is picked up and taken out using a conveyor belt with suction holes.

1 and q However, in a device like this that uses air ejected from an air nozzle to fan paper, the airflow not only flows between the topmost paper and the second paper, but also spreads between other papers, e.g. It also flows between the second sheet of paper and the third sheet of paper and tries to separate these sheets,
Moreover, there is no guarantee that the airflow between the top sheet and the second sheet is stronger than the airflow between the second and third sheets, so there is no separation between the second and third sheets. If the separation between the top and second sheets is sufficient compared to the separation between the top and second sheets, the top and second sheets may be fed at the same time, causing problems.

SUMMARY OF THE INVENTION The present invention aims to provide a paper feeding device which handles paper by airflow and which overcomes the above-mentioned drawbacks.

Therefore, in the present invention, there is provided a first nozzle group that supplies an airflow to float the uppermost sheet of the stacked sheets to a position where it can be sucked, and a A second nozzle group is provided between the sheet of paper and the sheet below it for supplying an airflow to separate the two sheets of paper.

According to the present invention, even if the airflow from the first nozzle group causes both the uppermost sheet of paper and the sheet below it to float, the airflow from the second nozzle group lifts the uppermost sheet of paper and the sheet below it. Since the paper is fed between the
No other separating means such as separating claws are required, and the separating effect is significantly improved using only airflow, eliminating the need for double feeding of sheets.

Furthermore, in the second aspect of the present invention, each nozzle of the second nozzle group is oriented such that each airflow supplied from these nozzles is concentrated on each other.

According to this invention, stagnation pressure is generated by the collision of the airflows from each nozzle of the second nozzle group, and therefore the pressure between the topmost sheet and the sheet below it increases, so that the separation effect is further improved. It increases.

Branch JJI Hereinafter, the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a schematic elevational view showing an embodiment of the first invention. Reference numeral 1 denotes a paper feed tray, on which a large number of sheets of paper 2 are stacked. A paper feed conveyor 3 is arranged above the paper feed tray 1. This paper feed conveyor 3 consists of a conveyor belt 6 stretched between a driving roller 4 and a driven roller 5, and the conveyor belt 6 has a large number of suction holes 7 passing through it in the thickness direction.
is provided. A vacuum box 8 that opens toward the paper feed tray 1 is arranged inside the paper feed conveyor 3 surrounded by the conveyor belt 6. The vacuum box 8 is connected to the intake side of the blower 10 via an intake duct 9 It is connected to the. Further, the intake duct 9 is provided with a suction valve 11 for sucking air through the suction hole 7 and the vacuum box 8, and an intake valve 12 for sucking air directly from the outside.

A discharge port of the blower 10 is connected to a nozzle box 14 via a jet duct 13, and the nozzle box 14 is provided with a first nozzle 15 and a second nozzle 16. The first nozzle 15 and the second nozzle 16 are each provided in a plurality of groups, and the first nozzle 15 is located at the same height as the top layer of the stacked sheets 2, as shown in the figure. It is also provided so as to be oriented parallel to the paper surface. In contrast, the second nozzle 16 is oriented slightly upward.

Reference numeral 17 is an actuator that detects the height of the paper 2. When several sheets of paper 2 are fed and the paper height becomes low, the actuator 1
7 is lowered to turn on the switch 18, which causes a motor (not shown) to rotate and raise the paper feed tray 1. Therefore, the top layer of the stacked sheets 2 is always the first layer.
It is held at approximately the same height as the nozzle 15.

The operation of this paper feeding device will be described below. First, the drive system and blower 10 (not shown) are activated by a start signal.
The air sucked into the intake duct 9 via the intake valve 12 is supplied to the nozzle box 14 through the jet duct 13, and the airflow jetted from the first nozzle 15 is blown onto the leading edge of the paper 2 in the uppermost layer. The tips of the two become levitated and are separated from each other. Next, the suction valve 11 opens in response to the paper feed signal (at this time, if the pressure inside the suction duct 9 increases, the suction valve 12 closes), and the suction force of the blower 10 is transferred to the suction hole 7 via the suction duct 9 and the vacuum box 8. As shown in FIG. 2, the floating uppermost sheet 2a is attracted onto the conveyor bell 1-6.

In this state, the airflow a ejected from the second nozzle 16 is blown between the top sheet 2a and the second sheet 2b, so that the airflow a completely separates the sheets 2a and 2b. . Note that, since the strong suction force of the blower 10 acts on the uppermost sheet 2a through the suction hole 7, it is attracted to the conveyor belt 6 regardless of the airflow a. Adsorption valve 1
1 is opened and a certain period of time has elapsed, a clutch (not shown) provided on the drive roller 4 is engaged, and the conveyor belt 6 is driven via the drive roller 4, and the uppermost sheet of paper adsorbed thereto is 2a is sent out to the conveyance roller 19.

When the leading edge of the paper 2a is detected by the sensor 20, the clutch is disengaged, the conveyor belt 6 is stopped, and the suction valve 11 is opened. At the same time, the intake valve 12 is opened due to the pressure difference between the inside and outside of the intake duct 9, so that the supply of air to the nozzle box 14 is continued.

FIG. 3 is a perspective view showing an example of the nozzle box 14 according to the second invention. Each nozzle 1 belonging to the first nozzle group
5.15 is oriented parallel to the paper surface in the uppermost layer of the paper 2 stacked on the paper feed tray 1, as in the above embodiment, but each nozzle 16a belonging to the second nozzle group
, 16b, and 16c are provided at an angle to each other so that the extensions of their respective axes are concentrated at approximately one point. Therefore, the airflows ejected from each nozzle 16a, 116b, 16c collide with each other, and the velocity is converted into pressure to generate so-called stagnation pressure, so the pressure between the uppermost sheet 2a and the sheet 2b below it increases, Both sheets 2a and 2b are separated more reliably by this pressure.

FIG. 4 is a drawing similar to FIG. 2 showing an example of a paper feeder having the nozzle box 14 shown in FIG. It is arranged. Therefore, the airflows ejected from each second nozzle 16 collide with each other and also collide with the airflow collision wall 21, generating even higher stagnation pressure and causing the sheets 2a, 2
Increase the pressure between b and enhance the separation effect of both sheets.

As described above, the paper feeding device of the present invention includes a first nozzle group that supplies an airflow that levitates the uppermost sheet of stacked sheets to a position where it can be sucked, and a Since it is equipped with a second nozzle group that supplies airflow between the topmost paper and the paper below to separate both papers, the topmost paper and the paper below it are separated by only the airflow from each nozzle group. It is possible to reliably separate the paper from the top paper, and only the topmost paper can be sucked and transported.

In addition, by orienting the nozzles of the second nozzle group so that the respective air flows supplied from these nozzles concentrate on each other, the stagnation pressure generated by the collision of the respective air flows causes the gap between the uppermost sheet and the sheet below it. By increasing the pressure, the effect of separating both sheets can be further enhanced.

[Brief explanation of drawings]

Figure 1 is a schematic elevational view showing one embodiment of the first invention;
3 is a perspective view showing a nozzle box according to the second invention, and FIG. 4 is a schematic elevational view showing an embodiment of the second invention. . DESCRIPTION OF SYMBOLS 1... Paper feed tray, 2... Paper, 3... Paper feed conveyor, 4... Drive roller, 5... Followed roller, 6...
...Transport belt, 7...Suction hole, 8...Vacuum box, 9...Intake duct, 10...Blower, 1
1... Adsorption valve, 12... Intake valve, 13...
・Fume duct, 14... Nozzle box, 15...
1st nozzle, 16... 2nd nozzle, 17... actuator, 18... switch, 19... conveyance roller, 20...
...Photo sensor, 21...Airflow collision wall. Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) In a paper feeding device that sucks and conveys the topmost sheet of stacked sheets, a first nozzle group that supplies an airflow that lifts the topmost sheet of the stacked sheets to a position where it can be sucked; A paper feeder comprising: a second nozzle group that supplies an airflow between the uppermost paper that has been floated and sucked and the paper below it to separate the two papers. (2) in a paper feeding device that sucks and conveys the topmost sheet of stacked sheets, a first nozzle group that supplies an airflow that lifts the topmost sheet of the stacked sheets to a position where it can be sucked; a second nozzle group for supplying an airflow between the floating and suctioned uppermost sheet of paper and the sheet below to separate both sheets, and each nozzle of the second nozzle group is configured to A paper feeding device characterized in that air currents supplied from the two are directed so as to concentrate on each other.