JPS6014274Y2 - Copy paper separation and conveyance device for electrostatic copying machines - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a copy paper separation and conveyance device for an electrostatic copying machine.

The copy paper on which the toner image on the drum has been transferred is moved close to the photosensitive drum and separated from the drum by sucking air between the leading edge of the copy paper and the surface of the photosensitive drum, and then transferred to the next fixing site. When the copy paper is placed on the conveyor belt that feeds it, air is sucked by an air suction member placed below the conveyor belt, and the copy paper is brought into close contact with the belt to ensure conveyance. Things have been well known for a long time.

In such devices, it is common to use dedicated blowers and fans, one for blowing air onto the photosensitive drum to separate the copy paper, and the other for sucking the separated copy paper onto the conveyor belt. be.

However, it goes without saying that such a configuration is undesirable because the number of parts increases, the structure becomes complex, and the space required within the copying machine also increases.

For this purpose, attempts have already been made to use a single blower to separate the copy paper from the photosensitive drum and to attract it to the conveyor belt in order to make the mechanism in this part more compact and reduce costs. It is being

However, when using a single blower like this, the amount of air suction differs when there is copy paper in the conveyance section and when there is no copy paper, especially when there is copy paper on the belt. The amount of air supplied to the blower is insufficient and a defect occurs that inhibits the separation action.

In order to prevent this blower from deteriorating in function, it is possible to compensate for the lack of air supply from the conveyor belt by providing an air intake near the blower. Although the separation ability of the paper is maintained, especially when using small-sized copy paper, the copy paper does not reach the conveyance belt sufficiently even after the auxiliary conveyance action based on the electrostatic attraction of the photosensitive drum is eliminated due to separation. Since the paper does not reach the copy sheet and air is supplied from the air intake port near the blower, the suction effect on the copy paper at the conveyance section is insufficient, and there is a concern that the conveyance operation becomes unstable.

It is obvious that in order to eliminate these drawbacks, it would be possible to use a large-capacity blower that can provide sufficient conveying force regardless of the size of the copy paper, but this would lead to increased costs and the need for a single It is clear that the advantages of using a blower are lost.

Furthermore, when using a blower to separate the copy paper from the drum, it is necessary to prevent the unfixed toner from scattering by recuperation, and from this point of view it is not desirable to increase the capacity of the blower. I think this is easy to understand.

The present invention aims to eliminate the drawbacks of the known copy paper separating and conveying apparatus using air as described above, and an embodiment thereof will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of the mechanism of this type of separation and conveyance device, in which a copy sheet P traveling in the direction of arrow A in the figure is transferred at a transfer section T of a photosensitive drum 3. The photosensitive drum is separated from the photosensitive drum by air blown from the blower 2 and reaches the conveyor belt 4 .

A suction case 1 is disposed below the conveyor belt 4 and has a large number of small holes facing the lower surface in the direction of movement of the belt, and the air inside the suction case is sucked by the blower through a duct (not shown). As a result, an air current is generated through the small holes that tends to bring the copy paper P into close contact with the conveyor belt, and as a result, the copy paper comes into strong contact with the conveyor belt and is reliably fed to the next process. .

This proposal is concerned with the improvement of the air suction casing placed on the conveyor belt in such a device that processes copy paper by blowing or suctioning air, and this is explained with reference to FIGS. 2 and 3. do.

In a conveyance path formed by a plurality of endless belts 4, a substantially hollow rectangular parallelepiped-shaped suction housing 1 is disposed between upper and lower belt running portions.

A large number of air suction holes 11 are formed on the upper surface of the casing, on the top surface on the copy paper conveyance side of the belt.

Reference numeral 2 denotes a blower, and its air outlet 22 serves to blow air toward the photosensitive drum, as schematically shown in FIG. 1, thereby contributing to the separation of copy sheets.

The air intake port 21 of the blower 2 is connected to the right side of the suction case in FIG. 2 through appropriate piping (not shown), and sucks the air in the cylinder as the blower operates.

The transferred copy paper is placed on the belt 4 and advances from the direction of arrow B in FIG. The vehicle travels while being pressed tightly in the direction of .

In this case, a lid plate 12 which is biased in the normally closed direction is disposed at a proper position of the suction housing 2, in the illustrated embodiment, on the side surface opposite to the side where the blower is connected, and furthermore, the suction housing A guide plate 14 is disposed inside to generate even greater negative pressure near the small hole 11.

As shown in FIG. 2, the lid plate 12 is configured such that its lower edge is hinged to the lower edge of the suction casing main body, so that it can be folded down into the casing, and can be rotated outward by an appropriate spring means (not shown). A falling portion 13 formed on the upper side edge of the housing with a dynamic tendency.
It is assumed that the valve is locked to maintain a normally closed state.

The spring means is configured such that when the inside of the cylinder exhibits a predetermined negative pressure, the cover plate is inclined inwardly and opened by external atmospheric pressure.

The copy paper is separated from the photosensitive drum by the air blown out from the blow-off port 22 by operating the blower, and is then placed on the conveyor belt 4 to advance in the direction of arrow B in FIG.

As the copy paper advances, the small hole 11 on the top surface of the suction housing 1 is gradually covered by the copy paper, weakening the air flow into the housing, and the negative pressure inside the housing increases.

When this negative pressure reaches a predetermined value, the cover plate 12 collapses inward against the spring force to open this part and air is supplied from this part, so the amount of air supplied to the blower 2 Since there is no shortage of paper and there is no change in the amount of balloons, copy paper separation work can be carried out without any problems.

Furthermore, in the present invention, there is a small hole 1 in the suction housing as described above.
Since the guide member is arranged to reduce the gap so as to speed up the air flow in the vicinity of at least a part of the belt 1 and obtain a larger negative pressure, the adsorption action of the copy paper to the belt in that part is increased, and the conveying action is increased. can be made certain.

Since the present invention has the structure and function explained above,
Even if a single relatively small-capacity blower is used, a sufficient amount of air for separation can always be obtained regardless of the presence or absence of copy paper on the conveyance path, and regardless of its size.

In addition, since a large negative pressure is actively obtained in the conveyance path, the copy paper can be strongly attracted to the conveyor belt and run reliably. This has the effect of obtaining high-quality copies without the risk of disturbing the image.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a copy paper separation and conveyance mechanism using air, and FIG. 2 is a perspective view of the main parts of the separation and conveyance mechanism according to the present invention.
FIG. 3 is a sectional view showing another embodiment of the suction housing. In the figure, reference numeral 1: suction casing, 2: blower, 3: photosensitive drum, 4: conveyor belt.

Claims (1)

[Claim for Utility Model Registration] A copy paper conveyance belt that feeds copy paper to the next process, and a hollow suction provided inside the copy paper conveyance belt and provided with a large number of small holes to attract copy paper. a housing, a blower communicating with the hollow suction housing; an air outlet communicating with the blower for applying airflow to the copy paper to separate the copy paper; a normally closed lid plate that is opened at a predetermined negative pressure within the hollow suction housing; and a guide member that is located within the hollow suction housing and narrows the airflow passage so as to reduce the dynamic pressure of the airflow passing near at least a portion of the small hole. A copy paper separation and conveyance device comprising: