JPH06596B2 - Pneumatic paper transport device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device used in a copying machine or the like, and more particularly to a sheet conveying device that utilizes air pressure.

[Conventional technology]

FIG. 9 is a plan view of a conventional air pressure type sheet conveying apparatus, FIG. 10 is a horizontal sectional view of the same, and FIG. 11 is a vertical sectional view of the same. A thin conveyor belt 2 is wound in parallel, and the roller 3 and the roller 4 are rotated around the conveyor housing 1 to convey the paper 6 on the platen glass 5 until it abuts on the paper stopper 7.

As shown in FIG. 10, a plurality of through holes 8 are provided at a predetermined position on the surface of the transport housing 1, and air is sucked from a suction port 9 at one end of the transport housing 1 to transport the air. Belt 2
A negative pressure is generated in the sheet suction unit 10 between them, and the sheet 6 is sucked toward the transport belt 2 so that the sheet 6 is reliably transported. Reference numeral 11 is an A-shaped separator for equalizing the negative pressure in the paper suction unit 10.

[Problems to be solved by the invention]

However, in the above-described transport device, when transporting a sheet 6 that is smaller than the area of the transport housing 1, when the sheet 6 is once stopped by the sheet stopper 7 and is transported again, the sheet 6 is removed from the sheet suction unit 10. There is a problem in that the paper sheet 6 drops, and the paper sheet 6 cannot be reliably transported, resulting in poor transportation.

This is because when the paper 6 is small, the paper 6 is located in the upper left corner of the transport housing 1 in FIG. 9, and there is a region on the surface of the transport housing 1 that is not blocked by the paper 6. Negative pressure is applied to the back side of the paper 6 (paper 6
12), the difference ΔP between the static pressure P1 in the transport housing 1 and the static pressure P2 on the back side of the sheet 6 becomes small, and the sheet 6 is sucked by the sheet suction unit 10 as shown in FIG. This is because the power to be sucked into is weakened.

The present invention has been devised to solve the above problems, and an object of the present invention is to provide a paper transporting device that can reliably transport paper even when the paper is smaller than the transport housing. And

[Means for solving problems]

According to the present invention, a plurality of through holes are provided in a transport casing around which a plurality of transport belts are provided, and air in the transport casing is sucked, so that a negative pressure is applied to the atmosphere between the plurality of transport belts. In an air pressure type paper transporting device in which a paper suction unit is formed, the small size paper transport area is located inside the transport housing and is closer to the suction port than the large size paper transport area. It is divided into a small-sized sheet conveying area and a large-sized sheet conveying area so as to be located on the downstream side in the direction, and the negative pressure of the sheet suction section in the small-sized sheet conveying area is set to the large-sized sheet conveying area. The pressure adjusting member, which has a larger pressure than the negative pressure of the sheet suction section, is provided.

[Action]

The sheet is conveyed by a plurality of conveying belts while being pulled by the negative pressure of the sheet suction unit, reaches the downstream side of the conveying case, and stops. At this time, due to the presence of the pressure adjusting member, the negative pressure of the paper suction unit is greater on the downstream side than on the upstream side in the paper transport direction, so that the paper exists even when transporting a small paper. Negative pressure is concentrated on the downstream side. As a result, even when a negative pressure atmosphere other than the area of the paper in the transport housing approaches a level close to the atmospheric pressure and a small paper is transported, the negative pressure is applied in the two directions of the paper transport direction and the direction orthogonal thereto. The sheet does not spread to the back side of the sheet, and the sheet is reliably sucked so that the sheet does not drop from the sheet suction unit when the conveyance is restarted.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the sheet conveying apparatus according to the present invention, the portions corresponding to those in FIG. 9 are designated by the same reference numerals, and the duplicate description will be omitted.

In FIG. 1, reference numerals 12, 13 and 14 denote plate-shaped resistors, which are the side surface of the transport housing 1, the vicinity of the suction port 9 and the partition plate, respectively.
It is provided near the apex of 11. Therefore, due to these resistors 12, 13, and 14, the inside of the transport housing 1 has a first region R1 for transporting small-sized paper near the suction port 9 and a region R2 of the table 2 for transporting large-sized paper. The third region R3 is divided into three regions. However, these regions R1, R2, and R3 are not completely separated, but communicate with each other through a gap S1 between the resistor 12 and the partition plate 11 and a gap S2 between the resistor 13 and the resistor 14.

Therefore, when the air is sucked from the suction port 9, the air in the second region R2 moves to the first region R1 through the gap S1 and is then discharged to the outside of the transport casing 1. Further, the air in the third region R3 moves to the first region R1 through the gap S2 and is then discharged to the outside of the transport housing 1.

At this time, the pressure in each of the regions R1, R2, and R3 can be set as shown in FIG. 3 by appropriately selecting the gaps S1 and S2.
The negative pressure P _{S0 in} the first region R1 is the largest, and the negative pressures in the second region R2 and the third region R3 are about (0.5 to 0.6) P _SO .

Now, considering the case where the small paper 6 is conveyed, when the paper 6 is stopped by the paper stopper 7, the paper 6 is located in the first region R1 for small-size paper conveyance. At this time, due to the air flow resistance action of the resistors 12, 13 and 14, the paper 6
Since the negative pressure in the regions R2 and R3 that are not blocked by is small, the negative pressure that spreads to the back side of the paper 6 is small.

Therefore, as shown in FIG. 4, the difference ΔP between the static pressure P1 in the transport housing 1 measured by the pressure gauge PG1 and the static pressure P2 on the back side of the sheet 6 measured by the pressure gauge PG2 becomes sufficiently large, Paper 6
Are reliably sucked by the paper suction unit 10.

When transporting large paper, the first region R1 for transporting small size paper and the second region for transporting large size paper
The sheet is sucked and conveyed by the sheet suction unit 10 in the three areas R2 and the third area R3.

FIG. 5 shows a second embodiment of the paper transporting apparatus according to the present invention. The parts corresponding to those of the first embodiment are designated by the same reference numerals and their duplicate description will be omitted.

In FIG. 5, reference numerals 15 and 16 denote shielding plates, which are provided between the side surface of the transport housing 1 and the partition plate 11, and between the vicinity of the top of the partition plate 11 and the suction 9, respectively. Electromagnetic valves 17 and 18 are provided penetrating the plates 15 and 16. Therefore, the transport housing 1 is provided by the shielding plates 15 and 16.
The inside is divided into a first region R1, a second region R2 and a third region R3, and these regions R are opened and closed by opening and closing the electromagnetic valves 17 and 18.
1, R2 and R3 are separated or connected.

Further, a sensor 19 for detecting the position of the sheet 6 is provided in the transport case 1, and the electromagnetic valve described above is selected according to the transport state of the sheet 6.
Controls the opening and closing of 17 and 18.

Now, considering the state where the paper 6 is carried in by the conveyor belt 2, initially the electromagnetic valves 17 and 18 are “open” as shown in FIG. 8A, and the output of the sensor 19 is as shown in FIG. 8B. "Low", the conveyor belt driving clutch (not shown) that controls the rotation stop of the conveyor belt 2 is "on" as shown in FIG. 8C, and the paper 6 is in each of the areas R1, R2 and R3. The sheet is conveyed while being sucked by the sheet suction unit 10.

At time T1, when the sensor 6 detects the sheet 6, the output of the sensor 19 becomes “high”, the conveyor belt driving clutch becomes “off”, the conveyor belt 2 stops, and the electromagnetic valve 17, 18 becomes "closed". Therefore, air is not sucked from the vent holes 8 in the regions R2 and R3, and the negative pressure in the regions R2 and R3 not blocked by the paper 6 becomes small, so that the negative pressure spreading to the back side of the paper 6 becomes small. As shown in FIG. 8D, the static pressure P1 in the transport housing 1 and the static pressure P2 on the back side of the paper 6
The difference .DELTA.P from .DELTA. Becomes sufficiently large, and the sheet 6 is reliably sucked by the sheet suction unit 10.

Even when the electromagnetic valves 17 and 18 are closed, the area R2,
Although the negative pressure of R3 does not become zero, as shown in FIG. 7, the negative pressure P _SO of the first region R1 is different from that of the second region R2 and the third region.
It is practically effective if the negative pressure in the region R3 is about (0.4 to 0.5) P _SO .

Further, when a predetermined time elapses, the conveyor belt drive clutch is turned on again at time T2, the conveyor belt 2 rotates, and this triggers the electromagnetic valves 17 and 18 to open.
Thus, the sheet 6 is conveyed while being sucked by the sheet suction unit 10 in each of the areas R1, R2 and R3.

〔The invention's effect〕

As described above, according to the present invention, even when a small sheet is conveyed, the negative pressure does not spread to the back side of the sheet in the two directions of the sheet conveying direction and the direction orthogonal to the sheet conveying direction. Will not be sucked reliably and will not result in poor conveyance.

[Brief description of drawings]

FIG. 1 is a transverse sectional view of a first embodiment of a sheet conveying apparatus according to the present invention, FIG. 2 is a longitudinal sectional view of the same, and FIG. 3 shows pressures in respective regions in a conveying case in the first embodiment. Graph, FIG. 4 is a graph showing changes in static pressure with time in the first embodiment,
FIG. 5 is a cross-sectional view of a second embodiment of the paper transporting device according to the present invention, FIG. 6 is a cross-sectional view taken along the line I--I of FIG. 5, and FIG. FIG. 8 is a graph showing the pressure in each region, FIG. 8 is a graph showing the operating state of each part in the second embodiment and the change over time in static pressure, and FIG. 9 is a plan view of a conventional air pressure type sheet conveying device. The figure shows the same cross section,
FIG. 11 is a longitudinal sectional view of the same, and FIG. 12 is a graph showing changes with time of static pressure in a conventional example. 1: Transport case 2: Belt 3, 4: Roller 5: Platen glass 6: Paper 7: Paper stop 8: Through hole 9: Suction port 10: Paper suction part 11: Separation plate 12, 13, 14: Resistor 15 , 16: Shielding plate 17, 18: Electromagnetic valve 19: Sensor

Claims (1)

[Claims] 1. A plurality of through holes are provided in a transport casing around which a plurality of transport belts are provided, and air in the transport casing is sucked so that a negative pressure is applied to the atmosphere between the plurality of transport belts. In an air pressure type paper transporting device in which a paper suction unit that serves as pressure is formed, in the above-mentioned transport housing, a small size paper transport area has a suction port side compared to a large size paper transport area It is divided into a small-size paper transport area and a large-size paper transport area so as to be located on the downstream side in the transport direction, and the negative pressure of the paper suction unit in the small-size paper transport area is used for the large-size paper transport area. An air pressure type sheet conveying device, characterized in that a pressure adjusting member is provided which is larger than the negative pressure of the sheet suction portion in the area.