JPH0734134B2 - Transfer peeling device for electronic copier - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer / peeling device for an electronic copying machine, and more particularly, to a transfer / peeling device for an electronic copying machine capable of obtaining a good copy density even in a high humidity environment. It is about.

[0002]

2. Description of the Related Art An outline of a transfer device of a conventional electronic copying machine is shown in FIGS. In the drawing, 1 is a photosensitive drum, 2 is a shunt for guiding copy paper, 3 is a transfer corotron using direct current discharge for charging the copy paper, and 4 is a resistance of about 100 MΩ. The transfer corotron 3 is composed of an shielded shield 3a and a wire 3b.

In such a transfer device, when the copy paper passes through the shoe 2 and reaches the position of the transfer corotron 3, the transfer corotron 3 is discharged to charge the back surface of the copy paper. On the other hand, a toner image corresponding to document information is formed on the surface of the photosensitive drum 1, and the toner image is carried at a position facing the transfer corotron 3 by the rotation of the photosensitive drum 1.

At this time, since the electric charge attached to the back surface of the copy paper and the electric charge of the toner have the opposite polarities, the toner image adhered to the surface of the photosensitive drum 1 is the same as that of the copy paper. Is sucked in and the toner is applied to the front side of the copy paper.
Is transferred. In this way, the toner on the photosensitive drum 1
The images are successively transferred onto a copy sheet, and the transferred copy sheet is conveyed toward a fixing device (not shown).

[0005]

By the way, when the copying machine is in a high humidity environment, the copy paper contains water, and the resistance of the copy paper decreases.

Then, in the transfer device of FIG. 3, the charges charged on the copy paper by the transfer corotron 3 are leaked through the shoot 2. Further, when the copy sheet comes into contact with or comes close to the shield 3a of the transfer corotron 3, the electric charge charged on the copy sheet is leaked or discharged through the shield 3a.

On the other hand, in the transfer device of FIG. 4, since the shunt 2 is held at a high voltage by the resistor 4, the electric charge charged on the copy sheet leaks through the shunt 2. Things are reduced. However, as described above, when the copy paper comes into contact with or comes close to the shield 3a of the transfer corotron 3, the charged electric charge of the copy paper is leaked or discharged through the shield 3a.

When the electric potential of the copy paper drops in this way, the electric field required for transfer cannot be obtained between the photosensitive drum 1 and the copy paper, and the copy density drops sharply.
There was a problem that a good copy could not be obtained.
Experimentally, in the transfer device shown in FIGS. 3 and 4, when the water content of the copy paper exceeds 8%, the copy density sharply decreases.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a transfer peeling apparatus for an electronic copying machine which has improved transfer efficiency and improved transfer dropout under high humidity. To provide.

[0010]

In order to achieve the above object, the present invention is arranged so as to face a photosensitive drum, and a shield and a transfer corotron wire to which a direct current is applied and an alternating current are applied. In a transfer peeling device of an electronic copying machine including a transfer peeling corotron having a peeling corotron wire and a paper traveling chute that guides a paper between the photosensitive drum and the transfer corotron, the shield is grounded via a high resistance The feature is that it is grounded.

[0011]

According to the present invention, the potential of the shield becomes a high potential having the same polarity as the DC potential applied to the transfer corotron wire, so that the transfer efficiency is improved even under high humidity and the transfer omission can be improved. it can.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic view of an embodiment of the present invention.

In the figure, 5 is a first resistance of about 100 MΩ, 6 is a second resistance of about 20 MΩ provided between the shoe 2 and the shield 8a, 8 is a transfer peeling corotron, and 9 is The resistor 10 is a capacitor.

The transfer peeling corotron 8 includes a shield 8a,
It is composed of a transfer corotron wire 8b to which a direct current is applied and a peeling corotron wire 8c to which an alternating current is applied. The capacitor 10 has a function of blocking the potential of the shield 8a from the ground and also grounding it in terms of alternating current. This may be a high resistance, or both of them may be connected in series or in parallel. May be. In addition,
Reference numerals other than these indicate the same as or equivalent to those in FIGS.

FIG. 2 shows the characteristics of the transfer device of this embodiment, in which the horizontal axis represents the transfer corotron applied voltage and the vertical axis represents the shoot inflow current and the shoot self-bias voltage. ing. The transfer corotron voltage in this embodiment is about 5.4.
As a result of using with KV, the shoot inflow current is 5-6 μA,
The self-bias voltage of the shoot became about 500 to 600V. The potential of the shield 8a is 600 to 700V.
It became about.

In this embodiment, when the copy sheet is sent to the position of the transfer corotron wire 8b through the space between the shoots 2, the copy sheet is transferred to the wire 8 as in the conventional apparatus.
It is charged by the direct current corona discharge generated between b and the shield 8a. Now, the water content of the copy paper is 8
%, The surface resistance of the copy paper becomes small and the charged electric charge of the paper is short 2 or shield 8.
In order to carry out the leak by transmitting "a", in the present embodiment, since the shoe 2 and the shield 8a are kept at a high voltage, there is no leak.

Therefore, a large electric field is generated between the copy paper and the photosensitive drum 1, and the toner image formed on the photosensitive drum 1 is almost the same as when the copy paper is dry. Transferred to copy paper. Therefore, according to this embodiment, it is possible to prevent the copy density from decreasing even when the copying machine is operated in a high humidity environment.

Further, in this embodiment, since the shields of the transfer corotron and the peeling corotron are made common and are connected to the ground via the high resistance, the potential of the shield is transferred to the AC component of the peeling corotron. Direct from Corotron
It becomes the bias voltage of the voltage that superimposes the flow component. Therefore, as a whole, the potential of the shield is
It will be shifted in the same polarity direction as the direction. According to
In any direction generated by the AC discharge of the peeling corotron.
Among the charged particles having the initial velocity of
Charged particles of the same polarity as the direction of repulsion by the shield
Is applied to the back side of high-humidity paper.
It easily adheres to the back surface of the paper. On the other hand, charged particles of the opposite polarity to the transfer corotron, which hinders transfer,
As a tendency, it receives a force in the direction of being attracted to the shield.
However, it also adheres to the back surface of the paper. As a result, the transfer efficiency is improved even in a high humidity environment,
Moreover, it is possible to prevent the occurrence of transfer omission , and
The peeling corotron can peel the paper.

Although the second resistor 6 is provided between the shoe 2 and the shield 8a in the above embodiment, it is not always necessary.

[0021]

As is apparent from the above description, according to the present invention, the following effects can be achieved.

(1) According to the present invention, as shown by the solid line a in FIG. 5, even if the water content of the copy paper is about 11%, a clean copy without transfer omission can be obtained. Was given. The dotted line b shows the characteristics of the conventional device.

[0023]

(2) Since the transfer corotron and the peeling corotron have the same shield and are connected to the ground via a high resistance, the transfer efficiency is improved and the transfer omission is prevented even under high humidity. Can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a first embodiment of the present invention.

FIG. 2 is a characteristic diagram of the device of FIG.

FIG. 3 is a schematic view of an example of a conventional device.

FIG. 4 is a schematic view of another example of a conventional device.

FIG. 5 is a characteristic diagram showing the effect of the present invention.

[Explanation of symbols]

1 ... Photosensitive drum, 2 ... Shoot, 3 ... Transfer corotron,
3a ... shield, 3b ... wire, 5 ... first resistance, 6 ...
Second resistance, 8 ... Transfer peeling corotron, 8a ... Shield, 9 ... Resistor, 10 ... Capacitor

Front Page Continuation (72) Inventor Akihiko Kato 2274 Hongo, Ebina City, Kanagawa Fuji Zerox Co., Ltd. Ebina Works (56) References US Patent 4077709 (US, A)

Claims (1)

[Claims] 1. A transfer peeling corotron having a shield, a transfer corotron wire to which a direct current is applied, and a peeling corotron wire to which an alternating current is applied, the shield being separated from the photosensitive drum, and the photosensitive drum and the transfer. A transfer peeling apparatus for an electronic copying machine, which comprises a paper traveling chute for guiding a paper between the corotron and the corotron, wherein the shield is grounded to a ground via a high resistance. .