JPS6348344B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves adhering toner to an electrostatic latent image formed on the surface of a photoreceptor, transferring the toner to copy paper under the application of a transfer electric field, and then separating the copy paper. Transfer of an electrophotographic copying machine designed to transport
The purpose of this is to improve the separation and conveyance device, and its purpose is to transfer the leading edge of the copy paper once to the copy paper by the transfer charger when the copy paper is dielectrically separated by the conductive separation and conveyance member. Even if the transferred toner image is reversely transferred to the photoreceptor and transfer failure occurs, separation is performed reliably.
Once separated, the separation performance is improved by ensuring that no transfer defects occur, and in particular keeping the peak voltage of the conductive belt constant during separation regardless of uneven charging of the copy paper, and setting the rising potential of each copy paper to zero potential. The aim is to prevent the deterioration of the separation properties and obtain very good separation performance.

The inventor of the present application first adsorbed toner to an electrostatic latent image formed on the surface of a photoreceptor, transferred the toner image to copy paper by applying a transfer electric field, and then transferred the copy paper to a conductive belt. They brought the conductive belt close to each other and generated a potential of the same polarity as the toner image on the copy paper on the conductive belt through electrostatic dielectric action, and separated the copy paper by adsorption to the conductive belt. As a result, the charge on the copy paper leaks through the conductive belt, reducing the number of electric lines of force between the copy paper and the transferred toner, and reducing the binding force of the toner particles to the copy paper. Therefore, the toner is reversely transferred to the surface of the photoreceptor, which has a strong suction force, and there has been a drawback that transfer omissions tend to occur in image areas such as line images where a large amount of toner adheres.

In the present invention, the conductive separation conveyance member described above is grounded by connecting a resistor and a constant voltage element in parallel, and only the separation effect of each copy paper is ensured at the leading edge of the copy paper, regardless of uneven charging of the copy paper. This method eliminates the drawbacks of the conventional method by ensuring the transfer action after separation and preventing transfer omissions.

Next, one embodiment of the present invention shown in the accompanying drawings will be described in detail. 1 is a photoreceptor drum on which a charged electrostatic latent image 2 is formed, and a charged toner 3 is formed on the surface of the photoreceptor drum.
is attached. Reference numeral 4 denotes copy paper, and a transfer electric field is applied to the pole by a transfer charger 5. Reference numeral 6 is a conductive belt made of sheet-like nickel having a thickness of 40 μm, and a resistor 7 and a constant voltage element 8 are connected in parallel and grounded.

Next, the effect will be explained. When a polar transfer electric field is applied to the copy paper 4 by the transfer charger 5, the polar toner on the photosensitive drum 1 is transferred to the copy paper 4. Next, copy paper 4
approaches the conductive belt 6, the capacitance between the copy paper 4 and the conductive belt 6 is C ₁ (t), and the capacitance between the copy paper 4 and the photosensitive drum 1 is C ₂
(t) and the capacitance between the conductive belt 6 and the photoreceptor drum 1 is C ₃ (t), then the equivalent circuit between the conductive belt 6 and the potential V(t) is as shown in Figure 2. As shown in FIG. 3, the potential V(t) of the conductive belt 6 is zero potential when the leading edge of the copy paper 4 first contacts the conductive belt 6, and the copy paper 4 gradually reaches the conductive belt 6. The potential of the conductive belt 6 gradually increases as it comes into contact with the conductive belt 6, becomes a constant potential _V1 by the constant voltage element 8, maintains this potential for a predetermined time, and then, when separation is completed, becomes zero potential by the resistor R. Repeat this. Incidentally, the separation performance is better when the potential of the conductive belt 6 is zero or close to zero, but for the reason mentioned above, the polar toner once transferred to the copy paper 4 is reversely transferred to the photoreceptor drum 1 at the moment of separation. easy to be However, this phenomenon occurs only at the leading edge of the copy paper 4 where it is separated from the photoreceptor drum 1; once the leading edge of the copy paper 4 is separated, the conductive belt 6 Constant polarity potential as shown in Figure 3
Since V ₁ is given, no transfer omission occurs in the image portion beyond a certain width (7 to 8 mm) from the leading edge of the copy paper 4. The peak voltage induced in the conductive belt 6 is maintained at a constant potential V ₁ by the constant voltage element 8 even if each copy paper is unevenly charged, and when separation is completed, it becomes zero potential by the resistor 8, so that the rise of each copy paper The potential becomes zero potential, and each copy sheet can obtain extremely stable and very good separation performance.

According to the present invention, since the conductive separating and conveying member is grounded by connecting the resistor and the constant voltage element in parallel,
Reliably prevents toner from being transferred during separation,
In particular, the peak voltage of the conductive belt during separation is kept constant regardless of the uneven charging of the copy paper, and the rising potential of each copy paper is set to zero potential to prevent deterioration in separation performance, resulting in very good separation performance. It has the characteristic that it can obtain the following.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is an equivalent circuit diagram relating to the transfer and separation of FIG. 1, and FIG. 3 is a graph showing the voltage of the conductive separating and conveying member of FIG. 1... Photosensitive drum, 2... Electrostatic latent image, 3... Toner, 4... Copy paper, 5... Transfer charger, 6
... Conductive belt, 7... Resistor, 8... Constant voltage element.

Claims (1)

[Claims] 1. Toner is attracted to the electrostatic latent image formed on the surface of the photoconductor, the toner image is transferred to copy paper under the application of a transfer electric field, and then the copy paper is separated from the photoconductor and transferred to a device that transports the toner. An electrophotographic copying machine is provided with a conductive separating and conveying member for separating and conveying the copy paper after transfer, and the conductive separating and conveying member has a resistor and a constant voltage element connected in parallel and grounded. Transfer, separation, and conveyance equipment.