JPH0442240A - Electrophotographic printing device - Google Patents

Abstract

PURPOSE:To prevent the material or the electric characteristic of a transfer belt from being changed and to improve the quality of printing and the reliability of a device by intermittently or always rotating the transfer belt at the non-printing time of the device. CONSTITUTION:A toner image on a photosensitive body 6 is transferred to a material to be transferred by attracting the material to be transferred to the transfer belt 1 which is electrostatically charged by corona discharging and carrying it. Besides, the belt 1 is set to be endless. Then, by successively or intermittently driving the belt 1 at the non-printing time, relative position between the belt 1 and corona dischargers 2 - 5 disposed by being faced to the circumference of the belt 1 is changed. Thus, since one part of the belt 1 is prevented from being concentrically exposed to O3 and NOX the material or the electric characteristic of the belt 1 is prevented from being changed and the quality of the printing or the reliability of the device is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an electrophotographic printing apparatus having a transfer belt.

[Background of the invention]

The disadvantages of the conventional method will be explained below with reference to FIG.

In an electrophotographic printing apparatus having a transfer belt, toner electrostatically adhered on the photoreceptor is transferred to the transfer material 11 as follows.

The surface of the transfer belt 1 is charged by the charging corona discharger 2, and the transferred material 11- is supplied to the transfer belt 1. The transfer material 11 is electrostatically attracted to the surface of the transfer belt 1 and is conveyed to the transfer process as the transfer belt 1 rotates. Since the transfer belt 1 is in contact with the photoreceptor 6 with a constant pressure, the transfer material 11 is in close contact with the photoreceptor 6 in the transfer area, and the toner on the photoreceptor 6 is removed by the discharge of the transfer corona discharger 3. is electrostatically transferred onto the transfer material 11. Thereafter, the transferred material 1 is separated from the photoreceptor 6 due to the rotation of the transfer belt 1.
After the charge is removed by the charge-eliminating corona discharger 4 and the electrostatic attraction force between the toner and the transfer belt 1 is weakened, the toner is separated from the transfer belt 1 and transported to a fixing process in which the toner is fixed onto the transfer material 11. Ru. After the charge remaining on the surface of the transfer belt 1 is removed by a corona discharger 5 for removing charge from the transfer belt, toner stains and the like are removed by a cleaning device 7.

As mentioned above, a corona discharger is arranged around the transfer belt 1. The corona discharger generates ozone (03) and nitrogen oxides (NOx) as discharge products during the printing operation of the electrophotographic printing apparatus.

With conventional electrophotographic printing devices, 03, which occurs during printing,
Since NOx remains in and around the corona discharger even during non-printing, the area around section A in the figure of the transfer belt 1, which is stopped during non-printing, is exposed to NOx. Since the transfer belt 1 is generally made of a polymer compound, there are problems in that material deterioration and electrical characteristics change due to NOx. If material deterioration or changes in electrical characteristics occur in the transfer belt 1, transfer defects or paper jams may occur due to poor adhesion between the transferred material 11 and the transfer belt, which is important for image quality and device reliability. This causes problems and also shortens the life of the transfer belt 1.

[Purpose of the invention]

An object of the present invention is to provide an electrophotographic printing apparatus that does not cause the above-mentioned problems in an electrophotographic transfer system using an endless transfer belt.

[Summary of the invention]

In the present invention, one of the major causes of the above-mentioned problems with the transfer belt is that the corona discharger and the transfer belt stop facing each other during non-printing, and one place on the transfer belt concentrates 03, NOx.
If you understand that the transfer belt is exposed to NOx and move the transfer belt constantly or intermittently relative to the corona discharger, you can prevent a portion of the transfer belt from being concentrated and exposed to NOx. With this in mind, we devised a way to drive the transfer belt when not printing.

[Embodiments of the invention]

A specific embodiment of the present invention will be described below with reference to FIG.

When the electrophotographic printing device is not printing, the transfer belt 1
stops rotating, and A section of the transfer belt 1 near the corona dischargers 2, 3, 4, and 5 disposed around the transfer belt (A section in the figure is 03. as described in the prior art section). 03) is generated by corona discharge during printing and begins to be exposed to the accumulated NOx.

Here, part A of the transfer belt 1 is stagnant 03, NOx
By keeping the time of continuous contact with the transfer belt 1 to less than a certain period of time and by preventing only one part of the transfer belt from coming into contact with NOx, local material changes in the transfer belt 1 caused by NOx and electricity can be avoided. Changes in physical characteristics can be suppressed. Therefore, the timer 8 is used as a rotation control means during non-printing.
By rotating the transfer belt 10N10FF in the direction of the arrow (B) at regular intervals using The effect can be obtained and the life of the transfer belt can be extended.

It should be noted that during one rotation of the transfer belt during non-printing, there is no need to activate or rub the corona discharger 2.3.4.5 or the cleaning device 7 for removing toner stains; The problem of shortening the life of the transfer belt due to rotation of the transfer belt does not occur.

In the above embodiment, the transfer belt 1 during non-printing
Although we have described the case where the timer 8 is used to control the rotation of the transfer belt 1, an 03 concentration detection member or a NOx concentration detection member is provided near the A section in the figure, and the rotation of the transfer belt 1 is turned on/off based on the 03/NOx concentration near the A section. ○The same effect can be obtained by performing FF.Also, even when not printing, the transfer belt 1
The same effect can be obtained even if the rotation is constantly rotated without stopping the rotation.

Furthermore, it is clear that even higher effects can be obtained by providing a fan to prevent 03/NOx from accumulating in the vicinity of section A of the transfer belt 1 and forcibly removing 03/NOx.

The above-mentioned non-printing time refers to a state in which the main body of the electrophotographic printing apparatus is in a printing standby state.

〔Effect of the invention〕

According to the present invention, by rotating the transfer belt intermittently or constantly when the electrophotographic printing apparatus is not printing, the corona discharger disposed around the transfer belt generates and accumulates 03 during printing. , the contact time between NOx and the local area of the transfer belt is shortened, and changes in the material and electrical characteristics of the transfer belt are prevented, which improves print quality and device reliability. It is possible to extend the life of l-.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of an electrophotographic printing apparatus according to the present invention. FIG. 2 is a sectional view showing an electrophotographic printing apparatus according to the prior art. In the figure, 1 is a transfer belt, 2 is a charging corona discharger, 3 is a transfer corona discharger, 4 is a static elimination corona discharger,
5 is a corona discharger for removing static electricity from the transfer belt.

Claims (1)

[Scope of Claims] 1. In an electrophotographic printing device in which a transfer material is adsorbed and conveyed to a transfer belt charged by corona discharge, and a toner image on a photoreceptor is transferred to the transfer material, the transfer belt is endless. Electrophotography, characterized in that it is provided with means for changing the relative position of the transfer belt with respect to a corona discharger disposed facing around the periphery of the transfer belt by driving continuously or intermittently during non-printing. Printing device. 2. The electrophotographic printing apparatus according to claim 1, further comprising an ozone concentration detection member or a nitrogen oxide concentration detection member for driving control of the transfer belt when the transfer belt is not printing. 3. The electrophotographic printing apparatus according to claim 1, further comprising means for forcibly removing ozone and nitrogen oxides remaining near the transfer belt.