JP2713586B2 - Transfer film removal method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer material such as transfer paper placed on a transfer film formed on a drum or a belt and rotating the transfer film. To a transfer device of a type in which the image is transferred to a photosensitive member to perform transfer.

2. Description of the Related Art In the above-described transfer device, electric charges remain in the transfer film after the transfer is completed. If the charge remains in the transfer film when the next transfer is performed, an abnormal image such as a so-called transfer omission may occur due to the influence of the remaining charge.

In order to remove the residual charge, an AC neutralization charger is disposed at a position downstream of the transfer position with respect to the circumferential rotation direction of the transfer film, and the residual charge of the transfer film is removed by discharging the AC neutralization charger, that is, the charge is removed. There is a device. However, there is a disadvantage that it takes a long time to reliably remove static electricity with a simple AC static charger.

Further, there is also known a device for removing an AC charger, instead of a simple AC charger, in which an AC voltage and a DC voltage are connected in series to a discharge wire to apply a DC-biased AC voltage. However, even in the case of this apparatus, it was not possible to reliably perform static elimination within a short time.

SUMMARY OF THE INVENTION The present invention provides a method for reliably removing electricity from a transfer film after transfer is completed within a short period of time, preventing a transfer failure from occurring in the subsequent transfer of a toner image, and removing transfer defects. It is an object to prevent occurrence of such an abnormal image.

Means and Action for Solving the Problems The above-mentioned problems can be solved by the following transfer film static elimination method.

The transfer material is conveyed to a transfer position facing the photoreceptor by the circumferential rotation of the transfer film formed by the dielectric material, and the transfer material conveyed to the transfer position is charged via the transfer film to the transfer material to thereby transfer the transfer material onto the photoreceptor. A transfer device for transferring the toner image onto a transfer material, wherein an AC charger is disposed downstream of the transfer position with respect to a circumferential rotation direction of the transfer film, and the transfer is also performed with respect to a movement direction of the transfer film. And a DC charger disposed downstream of the position. After the transfer is completed, the transfer film is further rotated at least two times, and the first rotation of the circumferential rotation is performed using both the AC charger and the DC charger. The transfer film is characterized in that the film is neutralized, and after the second rotation, the transfer film is neutralized only by the AC charger. It is a static elimination method.

In the above configuration, the transfer film is formed, for example, in a drum shape or a belt shape. A transfer material such as transfer paper is fixed so as to be in close contact with a transfer film formed in a drum shape or a belt shape. By the rotation of the transfer film, the transfer material fixed on the transfer film is carried to the photoconductor.

In a general transfer device, a transfer charger and a photoconductor are arranged to face each other with a transfer film interposed therebetween. Due to the discharge of the transfer charger, the toner image on the photosensitive member is transferred to the transfer material on the transfer film.

The transfer film is also charged by the discharge of the transfer charger. The transfer film needs to be neutralized so as not to adversely affect the next transfer. In the first rotation after the transfer of the transfer film, static elimination is performed by the DC charger and the AC charger. Efficiently reduce the transfer film potential to near Ov in a short time by DC neutralization. Thereafter, after the second rotation of the transfer film, static elimination is performed only by the AC charger, and the transfer film potential is accurately set to Ov.

Embodiment FIG. 1 is a schematic side view of an example of an electrophotographic copying machine using a static elimination method according to the present invention.

In the figure, a charging charger 16, a black developing device 11, a cyan developing device 12,
Magenta developing device 13, yellow developing device 14, transfer drum 1,
A magnetic brush cleaning device 15 is provided. The outer peripheral surface of the photoconductor 10 is uniformly charged by the charging charger 16, and is then image-exposed by the exposure device 17. By this image exposure, an electrostatic latent image is formed on the surface of the photoconductor 10. This electrostatic latent image is developed by any one of the developing units 11 to 14 into a toner image.

As shown in FIGS. 2 and 3, the transfer drum 1
A transfer film 1b made of a dielectric material such as a polyester film or a vinyl fluoride film and a clamping means 1c are fixed to 1a. A transfer charger 2 is disposed inside the transfer drum 1 so as to face the photoconductor 10. A transfer material, for example, a sheet-like transfer paper is wound around the transfer film 1b of the transfer drum 1, and is fixed by the clamp means 1c. The transfer drum 1 rotates counterclockwise, and the rotation causes the transfer material on the drum 1 to move according to the rotation of the photoconductor 10.

The transfer material on the transfer drum 1 is superimposed on the toner image formed on the photoconductor 10. At that time, the toner image is transferred onto the transfer material by the discharge from the transfer charger. The position where the transfer is performed is hereinafter referred to as a transfer position T.

A separation unit 7 and a paper discharging charger 6 are disposed downstream of the transfer position T with respect to the rotation direction of the transfer drum 1, that is, the transfer film 1b. After the transfer is completed, the transfer material is electrostatically attracted to the transfer film 1b under the influence of the discharge of the transfer charger 2. However, the paper is neutralized by the paper neutralizing charger 6 to reduce its adsorbing power. 7 peels off the transfer film 1b. The peeled transfer material is transported to the fixing device 9 by the transport unit 8,
After undergoing a fixing process by the fixing device 9, the sheet is discharged out of the apparatus.

According to this embodiment, a plurality of different copy modes such as a black copy mode, a simple mono color mode, a composite mono color mode, a full color mode, a black full color mode, and a photo original mode can be executed. The black copy mode is a mode in which copying is performed using one color of black toner. The simple mono color mode is a mode in which copying is performed using any one of yellow (Y), cyan (C), and magenta (M) toners. The composite mono-color mode is a mode in which a copied image is obtained by mixing any two colors of C, M, and Y, such as red, green, and blue. The full-color mode is a mode in which the color of the image itself is reproduced by superimposing all the C, M, and Y toners. The black full-color mode is a mode in which the color of the image itself is reproduced with all the C, M, and Y toners, and the black portion of the image is emphasized by copying the image with the black toner color separately. The photographic original mode is a mode in which the color of the image itself is reproduced by superimposing all the C, M, and Y toner images, but instead of superimposing the C, M, and Y images one by one for a total of three times, In this case, the image is in a color reproduction mode in which each image is superimposed a plurality of times, for example, each image is superimposed twice twice, for a total of six times. This mode is often used when copying a photo original in full color.

In the above-described copy modes, in the black copy mode and the simple mono color, the transfer is completed while the transfer film 1b makes one rotation. Also, the transfer film is rotated twice in the composite mono color mode, three times in the full color mode, four times in the black full color mode, and six times in the photo original mode.
The transfer ends while 1b rotates.

A DC neutralization charger 4 and an AC neutralization charger 3 are arranged in the downstream (downstream side) of the separation unit 7. Each of these chargers has an inner charger 3b and 4b and an outer charger 3a and 4a. The inner DC charger 4b performs a discharge having a polarity opposite to the discharge polarity of the transfer charger 2. On the other hand, the outer DC charger 4a is the transfer charger 2
Discharge of the same polarity as the discharge polarity.

Now, assuming that the transfer charger 2 performs a (-) polarity discharge, the transfer film 1 is charged to the (-) polarity inside by the discharge of the transfer charger 2, while the outside is charged to the (+) polarity. This charging potential is the transfer film 1b
If transfer is performed by the transfer charger 2 for the next copy process while remaining in the inside, abnormal transfer such as transfer omission may occur in the next copy process due to the influence of the residual potential. .

In this embodiment, the inside of the transfer film 1b is neutralized by the inner DC charger 4b which discharges the polarity opposite to that of the transfer charger 2, that is, the (+) polarity discharge, and the outside thereof has the same polarity as the transfer charger 2, ie, discharges the (-) polarity. Since the charge is removed by the outer DC charger 4a, the transfer film 1b charged by the transfer charger 2 is reliably charged. Also DC
In some cases, the potential of the transfer film 1b after the neutralization of the transfer film 1b by the neutralization charger 4 shifts to the (+) polarity or the (-) polarity. However, this shift is compensated by the AC neutralization charger 3, and the transfer film 1b is adjusted to the zero potential. You.

In particular, in the present embodiment, as shown in FIG. 4, the DC charger 4 operates immediately before the end of the final transfer, and
The AC neutralization charger 3 operates. And transfer film
After one rotation of 1b, only the DC neutralization charger 4 stops, and the AC neutralization charger 3 continues to operate for several rotations thereafter. By such a charge removing method, the charge of the transfer film 1b is reliably reduced to zero potential within a short time.

Generally, when the transfer film 1b is neutralized only by the AC neutralization charger, as shown in FIG. 5, the potential of the transfer film 1b becomes Ov in both polarities after a long time has passed. It is inefficient because it takes a long time to drop to Ov. On the other hand, if the transfer film 1b is neutralized only by the DC neutralization charger, the potential of the transfer film 1b can be reduced in a short time as shown in FIG. However, in DC neutralization, the charge of the opposite polarity to the charge on the transfer film surface is discharged.
There is an inconvenience that a potential of a polarity opposite to that before DC neutralization is applied.

In contrast, in the present embodiment, as shown in FIG.
First, the charged transfer film 1b is efficiently removed by DC
Lower to near Ov. Here, only the transfer film surface side will be described for convenience. The potential of the transfer film 1b during the DC neutralization is not necessarily the same, since it depends on the potential before the DC neutralization.
Next, the potential of the transfer film after DC neutralization is changed by AC neutralization.
Initialize to Ov. As described above, in this embodiment, a plurality of different copy modes such as a black copy mode and a full color mode can be executed, and the number of rotations of the transfer film 1b is determined depending on each copy mode.
That is, the transfer time is different. The fact that the transfer time is different means that the charge amount of the transfer film 1b is also different in accordance therewith.
It is desirable that the static elimination time is appropriately changed accordingly.

Effect In the present invention, the transfer film after the transfer is completed is neutralized by using the DC charger and the AC charger in the first rotation of the transfer film, and is neutralized by using only the AC charger in the second and subsequent rotations. Therefore, the transfer film can be reliably discharged to the Ov potential within a short time.

[Brief description of the drawings]

FIG. 1 is a schematic side view of an example of a copying apparatus capable of carrying out the method of the present invention, FIGS. 2 and 3 are views showing an example of a transfer film, and FIG. 4 is an embodiment of the present invention. FIG. 5 to FIG. 7 are timing charts showing the charge removal state of the transfer film. 1b: transfer film, T: transfer position, 10: photoconductor, 4: DC
Charger, 3 ... AC charger

Claims (1)

(57) [Claims] A transfer material is conveyed to a transfer position facing a photoreceptor by a circumferential rotation of a transfer film formed of a dielectric material, and a charge is applied to the transfer material conveyed to the transfer position via a transfer film. Accordingly, in a method for removing electricity from a transfer film in a transfer device for transferring a toner image on a photoreceptor onto a transfer material, an AC charger disposed downstream of the transfer position with respect to a circumferential rotation direction of the transfer film; A DC charger disposed at a position downstream of the transfer position in the moving direction, and after the transfer is completed, the transfer film is further rotated at least two times, and the first rotation of the circumferential rotation is the AC charger and the DC charger. The transfer film is neutralized using only the AC charger after the second rotation. Neutralization method of shooting the film.