JPH03227840A - Sheet feeder device - Google Patents

Abstract

PURPOSE:To make feeding action accurate by detecting that one end of laminated sheets is floated with air supply to a height appropriate for separation, storing the air flow control level at that time in a memory as the value corresponding to the optimum air flow rate, and controlling succeeding air flow rate based on the stored level. CONSTITUTION:The lowermost one of sheets 1 stacked on a sheet feeding table 2 is suctioned with a suction device while the rest of the sheets are floated to an optimum height with air supplied from an air supply nozzle 4. The floating is detected with a sensor 7. The control level of the air flow rate from the nozzle 4 at this time is stored as a value corresponding to the optimum air flow rate in a memory of a CPU. The air flow rate control thereafter is made on the basis of the stored air flow rate control level.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sheet feeding device in a copying machine or the like.

Conventional Technology For example, it is well known that a sheet feeding device in a conventional copying machine is configured to separate laminated sheets by supplying air. Because of this difficulty, conventional sheet feeding devices have had problems such as malfunctions (1) occurring in sheet feeding operations and damage to sheets.

In addition, there are also known configurations in which the air flow rate is variably set according to the seat size, seat weight, and seat friction force, but since it is set to a pre-calculated value, It was not possible to deal with variations in characteristics or differences in environmental conditions, and it was not always possible to sufficiently avoid sheet feeding errors (F) and sheet damage.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a sheet feeding device that can separate and feed sheets accurately and without damaging the sheets.

Means for Solving the Problems The present invention supplies air from one end side of a laminated sheet placed on a sheet supply table while controlling the flow rate to lift one end side of the laminated sheet. In a sheet feeding device that separates sheets from other sheets and sends them to a sheet feeding path.

One end of the laminated sheet is raised to the optimum height for sheet separation.
1-Level detection 1st stage to detect that the air pressure has - , a memory for storing a value corresponding to the appropriate air Al, and an air flow rate control means for setting the air flow l during a subsequent no-l operation to an appropriate air flow rate based on the control level stored in the memory. This is a sheet feeding device characterized by the following.

According to the present invention, the laminated sheet i is placed at the optimal height for sheet separation.
・The floating detection means detects that one end side has lifted up, and the air flow 1 control level at this time is stored in the memory as a value of 1- corresponding to the appropriate air flow rate, and based on the stored air flow rate ill fi level. Subsequent air a
III fil is performed. Therefore, the sheet separation and feeding operation becomes accurate, and sheet damage is also avoided.

Embodiment No. 1113 and FIG. 2 are vertical cross-sectional views showing the schematic configuration of a sheet feeding device according to an embodiment of the present invention, of which the first [21] shows a state in which the laminated sheet 1 is floating and the laminate 1- is FIG. 2 shows a state in which one end of the laminated sheet l is lifted up.

A laminated sheet 1 in which a plurality of sheets are piled up is placed on a sheet supply table 2, and in front of the sheet supply table 2 there is a pair of sheets for feeding sheets separated from the laminated sheet 1 to a paper feed path (not shown). Paper feed rollers 3a and 3b are arranged.

An air supply nozzle 4 for blowing air toward the front end of the laminated sheet 1 is provided in front of the sheet supply table 2.

Further, below the front of the sheet supply table 2, there is a sheet suction device 5 for sucking the lowest sheet of the laminated sheet 1 onto the sheet supply table 2 and separating the sheets; A sheet conveying device 6 is provided which conveys the sheet sucked by the sheet toward the sheet feeding rollers 3a, 31].

Knee above! - Is air sprayed from the air supply nozzle 4 to the lower part of the sheet supply table 2 further forward than the installation part of the suction device 5 and the sheet conveyance device 6? A floating detection sensor 7 is provided to detect when the front end of the laminated sheet 2 is lifted up to the optimal height for sheet separation by the air flowing. This floating detection unit 7 has a resilient piece 7a that is pressed against the lower surface of the laminated sheet 2 from below the sheet supply table 2 through a slit (not shown) formed in the sheet supply table 2.
and a switch 71 which is turned on, for example, when the resilient piece 7a protrudes to a certain height.

In addition, in front of the paper feed rollers 3a and 3b, a paper feed roller 3 is transferred from the sheet feed table 2 by the sheet conveying device 6.
A sheet detection sensor 8 is provided to detect the sheets fed into the sheets a and 3b, and a sheet detection sensor 8 is provided below the rear of the sheet supply table 2 to detect the size of the laminated sheet 2 placed on the sheet supply table 2. A size detection sensor 9 is provided.

FIG. 3 is a block diagram showing a schematic configuration of a control circuit in this sheet feeding device.

Central Processing Unit
Unit (hereinafter abbreviated as CPU) 10 is a circuit that controls the operation of the entire control circuit, and a read-only memory (Re
adOnly Me+aory (hereinafter abbreviated as ROM) 11, and a random read/write memory (Rando-^ccess Memory) that stores various data.
;hereinafter abbreviated as RAM) 12 is connected to CPU10. The fan motor drive circuit 13 is a circuit for driving the fan motor 14 used for the air supply nozzle 4, and is also a circuit for driving the fan motor 14 used in the air supply nozzle 4.
5 is a fan motor 1 used in the sheet suction device 5.
This circuit is for driving the CPU 10.
controlled by Further, the floating detection sensor 7 and the sheet size detection sensor 9 are connected to the CPU10, and the detection signals of these sensors are input to the CPU10.

FIG. 4 and FIG. 5 are respectively
Fig. 4 is a characteristic diagram showing various patterns of changes in the air flow rate at the air supply nozzle controlled by the air supply nozzle -1, among which Fig. 4 shows three patterns A, in which the air flow l increases and changes over time; 9. Figure 5 shows three patterns D, E, and F' in which the initial value of air KN is maximum and then the air flow l decreases with the passage of time. In addition, in FIGS. 4 and 5, the air flow I V
P indicates the air flow rate when the front end side of the laminated sheet 2 rises to the optimal height for sheet separation, that is, the appropriate air flow rate.

FIG. 6 is a timing chart 1 showing the operation of the sheet feeding device, of which FIG. 6(1) shows the ON signal of the start switch that starts the operation of the sheet feeding device, and FIG. ) shows the change in the flow rate of air blown out from the air supply nozzle 4, and FIG.
5 shows the change in inspiratory flow rate due to 6th e? 1(4) shows the detection signal of the levitation detection sensor 7, and FIG. 6(5) shows the detection signal of the seal l detection sensor 9.

Next, referring to the 6th I7I timing chart, the above sheet u i! The operation of the device will be explained.

When the start switch is turned on as shown in FIG. 6(1), the flow rate of air blown out from the air supply nozzle 4 gradually increases as shown in FIG. 6(2). When the air flow rate reaches the proper air flow rate VP, the front end side of the laminated sheet 2 placed on the sheet supply table 2 is raised by 1'' from the state shown in FIG. 1 as shown in FIG. 2. As a result, the elastic piece 7a of the levitation detection sensor 7 pressed against the lower surface of the front end of the laminated sheet 2 protrudes upward from the sheet supply table 2.
The switch 7b is turned on. That is, the levitation detection sensor 7 outputs a detection signal as shown in FIG. 6(4). Upon receiving this detection signal, the CP LJ 10 determines the current control level, which is a parameter for controlling the air flow rate of the air supply nozzle 4, as a value corresponding to the appropriate air flow rate ■P, and writes this control level into the RAM 12. It will be done. At the same time, a start command is given to the sheet suction device 5 from the CP controller 110, and an air supply stop command is given to the air supply nozzle 4, respectively. As a result, the air K I of the air supply nozzle 4 rapidly decreases as shown in Fig. 6 (1 (2)), and the intake flow rate of the sheet suction device 5 rapidly increases as shown in Fig. 6 (3). The lowest sheet of the sheets 2 is sucked onto the sheet supply table 2 by the sheet suction device 5.The air supply nozzle 4 restarts the air supply after a short time L1 after the -H air supply is stopped. The lowest sheet is moved by M3 from the laminated sheet.The control level of the air flow rate control at the time of restart is set to the value previously written in the RAM 12, that is, the value corresponding to the appropriate air flow rate ■P.Therefore, at the time of restart The air ilE 41 of the air supply nozzle 4 immediately reaches the appropriate air flow rate as shown in FIG.
When the drive starts, the paper is sent to the paper feed roller 3a3b@. During this time, the resilient piece 7a of the floating detection sensor 7 is pressed down by the separation sheet sucked onto the sheet supply table 2, and therefore no detection signal is output. The sheet is sent out from the sheet supply table 2 by the sheet conveying device 6! - is determined by the sheet detection sensor 8 in Fig. 6 (5)
It is detected as shown in . After the sheet is detected,
Predetermined time t 2 t! At t, the suction operation of the sheet suction device 5 is temporarily stopped as shown in FIG. 6(3). When the separation sheet separates from the levitation detection sensor 7, its resilient piece 7a protrudes onto the sheet supply table 2 again, and the detection signal rises again as shown in FIG. 6 (4), but in this case, the levitation The detection signal of the detection sensor 7 is not used for any timing. In other words, the detection signal of the levitation detection sensor 7 is used only to determine the timing when the air flow rate of the air supply nozzle 4 first reaches the appropriate air flow rate ■P. Ru. The detection signal of the sheet detection sensor 8 is the 6th [1I (5)
When the sheet falls as shown in , that is, when most of the separated sheets have been fed to the paper feed rollers 3a and 3b, the CPU10 issues an air supply stop command to the air supply nozzle 4 again to the sheet suction device. A suction restart command is given to each of the sheets 5 and 5, thereby starting the operation of separating and conveying the next lowermost sheet. In subsequent operations, the air flow rate when the air supply nozzle 4 restarts the air supply is always determined to be the appropriate air flow rate based on the control level written in n AM l 2 as described above. :LiV
Set to P.

Effects of the Invention As described above, according to the sheet feeding device of the present invention, the floating detection means detects that one end of the laminated sheet 1 has risen to a height suitable for separating the sheets, and The air flow rate control level is stored in memory as a value corresponding to the appropriate air flow rate, and subsequent air flow rate control is performed based on the stored air flow rate control level, so sheet separation and feeding operations can be performed easily. It is more accurate and sheet damage can be avoided.

[Brief explanation of drawings]

1 and 2 are vertical cross-sectional views showing a schematic configuration of a sheet feeding device according to an embodiment of the present invention, and FIG. 3 is a schematic configuration of a control circuit in the sheet feeding device. FIG. 4 and FIG. 5 are diagrams showing various patterns of time changes in the air flow rate of the air supply nozzle in the sheet feeding device, and No. 61 is a timing chart showing the operation of the sheet feeding device. be.

Claims (1)

[Claims] By supplying air while controlling the flow rate from one end side of the laminated sheet placed on the sheet supply table and lifting one end side of the laminated sheet, the bottom sheet is separated from the other sheets. In the sheet feeding device that separates the sheet from the stack and sends it to the sheet feeding path, there is a floating detection means that detects when one end of the laminated sheet has risen to the optimal height for sheet separation, and a floating detection means that detects when one end of the laminated sheet has risen to the optimum height for sheet separation. A memory for storing an air flow control level at the time detected by the detection means as a value corresponding to an appropriate air flow rate, and an air flow rate during a subsequent sheet separation operation based on the control level stored in the memory. A sheet feeding device comprising an air flow rate control means for setting an appropriate air flow rate.