JPS6056737A - Sheet feeder - Google Patents

Abstract

PURPOSE:To reliably adsorb and feed a sheet by increasing or decreasing the blower operation voltage for air jet according to whether the measured amount of time required for adsorbing the uppermost sheet on a tray to an adsorption belt is longer or shorter than a reference time. CONSTITUTION:According to an output signal of control means, a shut-down valve 24 is opened, and sucking force is worked upon the uppermost sheet 1a on a tray 2 by adsorbing means 40. Certain time later, the sheet 1a is adsorbed to a transport belt 3. At this time, the pressure in a duct 22 is remarkably decreased to open a relief valve 51, so that contact points 53, 54 are separated from each other. The time from opening of the valve 24 to separation of the contact points 53, 54 is measured, and the quantity of jet air of air jet means 10 is increased or decreased according to whether the measured time is longer or shorter than a reference time, so that the floating of the uppermost sheet 1a is made higher or lower. Thus, suitable sucking force works upon the sheet 1a corresponding to the thickness and rigidity of the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding device, and more specifically, the present invention relates to a paper feeding device.
and installing an air jetting means for jetting air to the end surface of the paper to separate the sheets from each other, and installing a suction means for sucking the paper to the conveyor belt,
A sheet feeder in which only the uppermost sheet of the sheets floated by the air jetting means is attracted to the conveyor belt by the suction means, and the uppermost sheet is conveyed by driving the conveyor belt. Regarding equipment.

[Prior art]

Conventionally, there is a paper feeding device that feeds paper on a tray using the suction force of air.

FIG. 1 shows an example of such a conventional paper feeding device.

In such a paper feeding device, a conveyor belt 3 is disposed above the end of a tray 2 on which a plurality of sheets of paper 1 are placed, and an air jetting means 1° is disposed in front of the tray 2.
A suction means 20 is installed on the conveyor belt 3. here,
The conveyor belt 3 has a large number of holes 3a formed throughout, and is wound around a conveyor belt drive roll 4a and its follower roll 4b. Note that the conveyor belt 3 is driven at a predetermined timing, as will be explained later. Further, the air blowing means 1o includes a blower 1, a duct 12, a nozzle plenum 13, and the like. The nozzle plenum 13 includes a nozzle 13a.

13b is formed. That is, the air blowing means 1
At 0, air is drawn into the blower 11 from the atmosphere and sent into the nozzle plenum 13 via the duct 12. Further, the air is ejected to the end surface of the paper 1 through the nozzle plenum 13 and the nozzle 13m, and is also ejected to the front end of the conveyor belt 3 via the nozzle 13b. The adsorption means 20 includes a vacuum pump 21, a duct 22, and a vacuum plenum 23.
Consists of etc. The vacuum plenum 23 has an open bottom surface. That is, in this suction means 20, the air in the vacuum plenum 23 flows into the duct 22.
The air is sucked into the vacuum pump 21 through the vacuum pump 21, and discharged into the atmosphere from the vacuum pump. At that time, the negative pressure generated in the vacuum plenum 23 causes the opening 23a of the vacuum plenum 23 and the hole 3a of the conveyor belt 3 to
A suction force is applied to the paper 1 on the tray 2 through the . In FIG. 1, 5 is an elevator tray that supports the tray 2 in a vertically movable manner, 6a and 6b are paper guides installed on the tray 2, 7a is a drive roll for transporting paper, and 7b is a driven roll for transporting paper. , 8 is a transport paper detection switch (reset type normally open switch), 9 is a paper transport guide,
24 is a normally-closed shutdown valve installed in the suction side duct 22, and 30 is a valve for increasing the stack height from the bottom plate 5a of the elevator tray 5 to the top of the paper 1 on the tray 2.
1a) detection switch (self-resetting normally open switch).

Next, the operation of the paper feeding device will be explained with reference to FIGS. 2(a), 2(b), and 2(e).

In such a paper feeding device, when a power switch is closed, a start signal is issued from a control section (not shown), and the blower 11 and vacuum pump function 21 are operated. Then, the sheets of paper located above the sheet of paper 1 are separated from each other and floated by the air jetted from the nozzle 13a (see FIG. 2(,)). Next, when the operator operates a paper feed start button (not shown), a feed signal is generated from the control section. Then, a solenoid for driving a shutdown valve (not shown) is activated, and the shutdown valve 24 is opened. As a result, suction force by the suction means 20 is applied to the uppermost sheet 1a of the sheets 1, and the sheet 1a is suctioned to the conveyor belt 3 (see FIG. 2(b)). At this time, the air ejected from the nozzle 13b is applied to the uppermost sheet 1a and the sheet 1 directly below the sheet 1&.
b, thereby causing paper 1a and paper 1
b is greatly separated. Furthermore, after a predetermined period of time has elapsed since the feed signal was issued, a feed signal is issued from the control section, and an electromagnetic clutch for driving the conveyor belt (not shown) is actuated, whereby the power of the drive device (not shown) is applied to drive the conveyor belt. It is transmitted to the roll 4a, and the conveyor belt 3 is rotationally driven. Thereby, the conveyor belt 3
The paper 1a that has been attracted to the paper 1a is sent out along the transport belt to the paper transport rolls 7a and 7b. moreover,
The paper 1 & is nipped by paper transport rolls 7a and 7b and sent to the next paper processing step (not shown).

At this time, the sheet 1a activates the actuator 8a of the conveyed sheet detection switch 8 to close the conveyed sheet detection switch (see FIG. 2(C)). When the control section receives the closing signal of the conveyed paper detection switch 8,
The control section cuts off the generation of the feed signal and the conveyor belt drive signal, closes the shutdown valve 24, and stops the rotation of the conveyor belt 3. After the paper 1a is completely fed out from the paper transport rolls 7a and 7b, the actuator 8a of the transport paper detection switch 8 returns to its original position, the transport paper detection switch is opened, and the next paper feeding operation begins. It becomes possible. Then, when the next feed P signal is issued by the control section, the paper feeding operation is repeated. Note that in this paper feeding device, when the stack height of paper 1 becomes lower as paper feeding progresses, the topmost paper of paper l at that time is moved to the actuator 30a of the stack height detection switch 30. The stack tray 2 is moved upward by elevator means (not shown) until the stack height detection switch is closed upon contact with the stack height detection switch, and the uppermost sheet is positioned at a height within a certain range.

By the way, in such a conventional paper feeding device, the flow rate of the blower 11 is always constant regardless of the thickness of the paper 1, so when the paper 1 is thin paper, the plurality of sheets 1 are floated significantly. If the paper 1 is made of thick paper, it may be difficult for the paper 1 to float sufficiently due to its own weight and rigidity. For this reason, the paper 1 cannot be attracted to the conveyor belt 3, and there is a possibility that the paper cannot be fed.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a paper feeding device that can reliably feed paper regardless of the thickness or rigidity of the paper.

[Structure of the invention]

In order to achieve the above object, the present invention includes a measuring means for measuring the time from when the suction means starts suction until the top sheet of paper on the tray is attracted to the conveyor belt, and the measuring means If the measured time is longer than the reference time, the applied voltage to operate the blower in the air jetting means is increased, and if the measured time is shorter than the reference time, the applied voltage is decreased. A means is installed to levitate the uppermost sheet of paper to an appropriate height, so that an appropriate suction force of the suction means is applied to the sheet of paper in accordance with the thickness and rigidity of the sheet of paper. .

〔Example〕

Hereinafter, a paper feeding device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 shows a main part of an embodiment of a paper feeding device according to the present invention. In FIG. 3, the same elements as those shown in FIG. 1 are designated by the same reference numerals.

In the paper feeding device of this embodiment, the duct 22 of the suction means 40
A relief valve 51, which forms part of a measuring means 50 (see FIG. 4) which will be described later, is installed at the bottom. This relief valve 51 has a hole 2 bored in the duct 22:
lf, and is configured to be normally closed by the valve body 52. The valve body 52 is pin-coupled to the duct 22 at one end, and has a contact 53 formed at the other end. This valve body 52
A contact point 54 is formed in the duct 22 corresponding to the contact point 53 . Further, a weight 55 is attached to the valve body 52,
The relief noggle 51 is closed by the weight of the weight. The measuring means 50 measures whether the uppermost sheet 1a of the sheets 1 on the sheet tray 2 is loaded after the shutdown pulp 24 of the suction means 40 is opened, that is, after the suction means applies a suction force to the uppermost sheet 1& of the sheets 1 on the tray 2. It measures the time spent in the trench being attracted to the conveyor belt 3, and is equipped with a counter and the like in addition to the relief valve 51 mentioned above. Furthermore, this paper feeding device includes 60 ft of control means for controlling the voltage applied to the blower 11. That is, as shown in FIG. 4, the control means 60 compares the reference time T1, which is preset according to the thickness and rigidity of the paper 1 set on the tray 2, with the time T2 measured by the measuring means 5o. However, the measurement time T2 is the reference time T! If the length is too long, the blower 11 of the air jetting means 10 can be controlled by the operating section 61 of the control means.
The number of revolutions of the blower is increased by increasing the voltage applied to the blower, and the amount of air ejected from the air ejecting means is increased. If the measurement time T2 is shorter than the reference time T□, the operation unit 61 decreases the voltage applied to the blower 11 to reduce the rotation speed of the blower and reduce the amount of air jetted from the air jetting means. It has the function of reducing

In FIG. 3, 56 is a switch for stopping the tray 2 at the initial position when moving the tray 2 upward after setting the paper 1 on the tray 2, and 57 is a switch for stopping the tray 2 at the initial position.
This is a switch for safety by stopping the tray 2 by cutting off the power supply to the drive motor of the elevator means (not shown) that moves the tray up and down when the tray 2 goes out of control.

Next, the operation of this embodiment will be explained with partial reference to FIG. 1 and also with reference to FIG. 5, and the configuration of this embodiment will also be clearly explained. FIG. 5 shows the characteristics of the suction means 40 in the paper feeding device of this embodiment.
A is the characteristic curve of the pump 21, B is the paper 1 on the tray 2
A curve showing the relationship between the suction force P and the flow rate Q in the suction means 40 before the top sheet 1a is attracted to the conveyor belt 3; It is a curve showing the relationship between the suction force P and the flow rate Q in the suction means 40.

In this paper feeding device, as in the case of the paper feeding device shown in FIG. 1, when a start signal is output from the control means 6o,
When the blower 11 and the pump 21 are activated and then a pre-feed signal is output from the control means 6o, the shutdown valve 24 is opened and the suction means 40 absorbs the uppermost sheet 1a of the sheets 1 on the tray 2. A preset initial suction force Pa is applied. The operating point of the suction means 4° at this time is indicated by ■ in FIG. Its suction power Pa
However, the uppermost sheet 1a is adsorbed onto the conveyor belt 3 after a certain amount of time. At this time, the adsorption means 40
The operating point of moves from ■ to ■ in FIG. The suction force pb at that time is considerably larger than the suction force Pa.

Therefore, at this time, since the pressure inside the duct 22 is greatly reduced, the relief pulp 51 is opened against the weight of the weight 55, and the contacts 53 and 54 that were in contact with each other until then are opened.
are separated from each other. Here, the measuring means 5o is connected to the contacts 53 and 54 after the shutdown valve 24 is opened.
Complete the measurement of the time until they are separated from each other. Here, the measurement time T2 by this measuring means 50 is the reference time T1
If the paper is too long (such as when the paper 1 is thick and heavy), the air ejected from the air ejecting means 1o is increased by an amount corresponding to the difference between the measurement time T2 and the reference time TI, and The uppermost sheet 1a of the sheets 1 on the tray 2 is floated higher by the increase. As a result, the time required for the uppermost sheet 1a to be sucked by the conveyor belt 3 after the suction force is applied to the suction means 4o is reduced.
The time is shortened and brought closer to the reference time T1. Also,
When the measurement time T2 by the measurement means is shorter than the reference time T1 (such as when the paper 1 is thin and light), K is the amount of air ejected from the air ejection means 10, which is the size of the difference between the measurement time T2 and the reference time Tl. The air is reduced by an amount corresponding to the amount of air, and the top paper [a] is floated lower by the amount of air reduction.

As a result, the uppermost sheet 1a is transferred to the suction means 40.
The time required from when the suction force is applied to when the paper is attracted to the conveyor belt 3 is made longer and closer to the reference time T1.

〔Effect of the invention〕

As described above, the paper feeding device according to the present invention can reduce the time required for the topmost sheet of paper on the tray to be attracted to the conveyor belt after the suction force is applied by the suction means. Since the time is set close to the preset reference time according to the thickness and rigidity of the paper, it is possible to give the paper an appropriate amount of levitation according to its thickness and rigidity, and thereby the thickness and rigidity of the paper can be adjusted. An appropriate suction force can be applied to the uppermost sheet of paper accordingly. Therefore, if the paper is thin paper, there is no risk of double feeding, and if the paper is thick paper, there is no risk of paper feeding being impossible.
Paper can be fed reliably.

[Brief explanation of the drawing]

Figure 1 is a conceptual diagram showing a conventional paper feeding device, Figure 2 (a)
, (b) and (c) are conceptual diagrams showing the effect, Part 3
The figure is a conceptual diagram showing one embodiment of the paper feeding device according to the present invention, FIG. 4 is a block diagram of its control means, and FIG. 5 is a graph showing the action of its suction means. 1...Paper, '-1a...Top paper, 2...
Tray, 3... Conveyor belt, 3a... Hole, 4a...
・Transport belt drive roller, 4b...driven a-ra, 10
...Air blowing means, 11...Blower, 12...
Duct, 13... Nozzle plenum, 13m, 13b
...Nozzle, 21...? Nzo, 22... duct,
22a... hole, 23... Gukyumzolinum,
24... Shutdown valve, 30... Stack height detection switch, 40... Adsorption means, 50... Measuring means, 51... Relief valve, 52... Valve body,
53.54... Contact, 55... Weight, 60...
- Control means, 61... operation unit. Figure 1 1 11 Figure 3 Mn Figure 2 (0) (b) (C)

Claims (1)

[Claims] A conveyor belt is disposed above the end of the tray on which the paper is placed, and an air jetting means is installed to spray air onto the end surface of the paper to separate the paper from each other,
A suction means for attracting the paper to the conveyor belt is installed, and only the uppermost sheet of the paper floated by the air jetting means is suctioned to the conveyor belt by the suction means, so that the uppermost sheet is In the sheet feeding device configured to convey the paper by driving the conveyor belt, a measuring means is installed for measuring the time from when the suction means starts suction until the uppermost sheet of paper is attracted to the conveyor belt. At the same time, if the measurement time by the measurement means is longer than the reference time, the applied voltage for activating the roller in the air jetting means is increased, and if the measurement time is shorter than the reference time, A paper feeding device characterized in that a control means for reducing the applied voltage is installed to levitate the uppermost sheet of paper to an appropriate height.