JPS63223681A - Cleaning device - Google Patents

Abstract

PURPOSE:To improve cleanability by providing a stationary conductive brush applied with the voltage to remove the electric charge potential of a dielectric material or to reverse the polarity of the potential in proximity to the dielectric material surface on the upper stream side of the traveling dielectric material viewed from a rotary brush. CONSTITUTION:A toner is strongly attracted to the dielectric material 1 when the polarity of the electric charge of the toner and the polarity of the dielectric material 1 to which the toner adheres are reverse from each other. The conductive brush 2 fixed to the position on the upper stream side of the traveling material 1 viewed from the position of the rotary brush 4 for removing the toner from the surface of the material 1 is installed in proximity to the surface of the material 1 and the voltage to remove the charge potential of the material or to convert the same to the reverse polarity is applied to said brush 2. The unnecessary toner adhering to the material 1 is thereby easily transferred to the brush side, by which the cleanability is improved and the generation of gas such as ozone is obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cleaning device for removing toner adhering to a moving dielectric surface in equipment such as copying machines and printers using electrophotographic technology.

Conventional technology In electrophotographic copying machines and printers, in order to remove unnecessary toner adhering to the photoconductor surface and the belt surface of the transfer/conveyance device that conveys the transfer material and transfers the image to the transfer material, Cleaning devices using rubber-elastic blades or rotating fur brushes are used. Cleaning devices that use rubber-elastic scraping blades have good cleaning efficiency, but if hard toner such as magnetic toner is sandwiched between the blade and the scraping surface, the cleaning surface is likely to wear out. There is a problem.

A cleaning device using a fur brush has a problem in that cleaning efficiency is not good, although the cleaning surface is only slightly abrasive. In fur brush cleaning, the toner on the dielectric adheres to the fibers of the fur brush and is removed from the dielectric surface. However, when the dielectric and toner have opposite polarities, the electrostatic charge between the toner and the dielectric increases. The attractive force is strong, making it difficult for toner to move toward the brush, making it impossible to perform sufficient cleaning.

US Pat. No. 2,832,977 describes a cleaning device that removes unnecessary toner with a fur brush after neutralizing the surface of a traveling charged photoreceptor with a coronatron. By neutralizing the surface of the photoreceptor, which is charged to the opposite polarity to that of the toner, the attraction force of the charged toner to the surface of the photoreceptor is reduced, making it easier for the toner to move to the brush.

Problems to be Solved by the Invention When using a coronatron and a rotating fur brush as a cleaning device for cleaning charged dielectric surfaces such as photoreceptors, harmful gases such as ozone and nitrogen oxides are generated due to corona discharge. There was a problem.

Means for Solving the Problems In order to solve the above-mentioned problems, the cleaning device of the present invention has the following features: A fixed conductive brush is provided at an upstream position close to the dielectric surface and to which a voltage is applied to remove the charged potential of the dielectric or convert the polarity of the potential to the opposite polarity.

action The effects of the above technical means will be described.

As already mentioned, when the polarity of the charge on the toner and the polarity of the dielectric material to which the toner is attached are opposite, the toner is strongly attracted to the dielectric material. A conductive brush fixed at a position on the upstream side of the traveling dielectric as seen from the position of the rotating brush for removing toner from the dielectric surface is installed close to the surface of the dielectric, and the conductive brush is attached to the surface of the dielectric. By applying a voltage that removes the charged potential or converts it to the opposite polarity, unnecessary toner adhering to the dielectric material is easily transferred to the brush side, improving cleaning performance. That is, by removing the charge on the dielectric material (<reducing the absolute value of the charged potential or reducing the potential to zero), the attraction force between the adhered toner and the dielectric material is reduced. Further, by reversing the polarity of the dielectric material using the fixed conductive brush, that is, by making it the same polarity as the charged toner, the adhered toner receives a force of repulsion from the dielectric material.

In order to remove the static electricity from the running charged dielectric body or to convert the charged potential to the opposite polarity, basically, a voltage with a polarity opposite to the charged polarity of the dielectric body is applied to the fixed conductive brush. It will be done.

Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a side view of an embodiment of the cleaning apparatus of the present invention.

The running dielectric (hereinafter simply referred to as dielectric) 1 is a dielectric layer 1
It consists of a conductive layer 1b which is electrically grounded and serves as a back electrode, and runs toward the right hand side in the figure. The surface of the dielectric 1 is charged to a positive potential before reaching the fixed brush 2.

A negative voltage is applied to the fixed conductive brush by a power source 8. After passing through the fixed conductive brush 2, the charged potential of the dielectric 1 is neutralized or turned negative. Unnecessary negatively charged toner 3 adhering to the surface of the dielectric 1 comes from the left side of FIG. 1, passes through the fixed brush position, and reaches the rotating conductive brush 4. The conductive brush 4 rotating zero is a dielectric. A positive voltage is applied by a power source 9 to the conductive brush 4 which rotates at 0 and is in contact with the surface of the dielectric body l, rotates in a direction opposite to the travel of the dielectric body l, and is in contact with the rotating toner collection rod 5. When the negatively charged toner 3 reaches the zero-rotating conductive brush applied via the static toner collection rod 5, the positive charge on the dielectric body 1 is eliminated or converted to negative, and the force to attract the toner is reduced. Because of this, it easily transfers to a rotating conductive brush to which a positive voltage is applied.
Next, the process moves to the toner collection rod 5. The toner adhering to the surface of the toner collection loft 5 is collected into a toner collection box 7 by a scraping blade 6. Cleaning device 2
Each part of 0 is housed in a case 10.

Next, an example will be described in which the cleaning device of the present invention is applied to conveying a transfer material and cleaning toner on a transfer belt in a laser beam printer.

FIG. 2 is a diagram showing an overview of the copying process of a laser beam printer. As described in FIG. 1, the belt-shaped dielectric 1 is composed of a multilayer structure including an outer dielectric layer 111a and an inner conductive layer 1b. The belt-shaped dielectric body 1 includes belt-suspended rollers 31a, one of which is a driving roller;
31b and travels in the direction of the arrow in the figure. The conductive layer 1b of the belt-like dielectric 1 is electrically grounded by one of the conductive suspension rollers. The circumference of the photoreceptor 32 contacts the dielectric layer 1a of the belt-shaped dielectric 1 and runs in synchronization with the running of the belt-shaped dielectric. The photoreceptor 32 is charged to a potential of about -700 cm by the coronatron 33, and then exposed to a laser beam signal to form an electrostatic latent image. This electrostatic latent image is subjected to so-called reversal development by a developing device 34 using negatively charged toner to form a developed image on the surface of the photoreceptor. The belt-shaped dielectric material 1 is charged to approximately +1.6 kV by the coronatron 35, and with the help of this charging and the biting roller 37, a transfer material 36 such as paper supplied from the right side of the figure is charged to the belt-shaped dielectric material. It is sucked and transported to the left in the figure. At the contact point between the belt-like dielectric and the photoreceptor, the negatively charged toner image on the photoreceptor is electrostatically transferred onto the transfer material by the positively charged potential of the belt-like dielectric.

The transfer material is conveyed to the left in the figure while being attracted by the belt-shaped dielectric material, and heads for the next fixing step.

In the above process, if for some reason the timing at which the transfer material is conveyed is off, or if the transfer material is not conveyed when it should, the toner image on the photoreceptor will not be transferred to the belt-like dielectric surface. Ru.

If this toner is not removed, it will adhere to the back side of the transfer material during the next transfer cycle. Therefore, the above-mentioned cleaning device 20 is provided to remove unnecessary toner adhering to the surface of the belt-shaped dielectric material.

The above rotating conductive brush or fixed conductive brush is
For example, it is made of a material in which rayon, nylon, or other synthetic fibers containing fine carbon fibers or particles to make them conductive are embedded in a cloth as a base material. The electrical resistance of the brush is measured from 104 to I in the longitudinal direction of the flocked fiber group.
QIOΩ・1.

FIG. 3 shows an example of the relationship between the surface potential of the belt-shaped dielectric material immediately before passing through a fixed brush and the surface potential of the belt-shaped dielectric material immediately after passing through a fixed conductive brush in the apparatus shown in FIG. 2. It is something that

The surface potential of the moving dielectric immediately before passing the fixed conductive brush is +1, 5 kV. Further, the gap between the fixed conductive brush and the running dielectric surface is 1.3fi.

In the laser beam printer shown in Fig. 2, a surface potential of +1.6 kV is applied to the belt-shaped dielectric material using the coronatron 35, the voltage of the fixed conductive brush is adjusted, and the belt-shaped dielectric material immediately after passing through the fixed conductive brush is By setting the surface potential in the range of +lkV to -0.5 kV, the toner transferred from the photoreceptor to the surface of the belt-shaped dielectric material could be efficiently cleaned. Note that the preferred value of the positive voltage to be applied to the rotating conductive brush is in the range of 500 to 1500 V, although it varies depending on the value of the surface potential of the running dielectric after static elimination or polarity reversal.

Almost no ozone was observed to be generated from the cleaning device of the present invention.

Note that the above-mentioned embodiments have been described in the case where the toner has a negative charging polarity and the belt-like dielectric has a positive charging polarity, but it can also be applied to a case where the charging polarity is the opposite combination. Furthermore, this cleaning device can also be applied to cleaning photoreceptors.

Effects of the Invention As stated above, the cleaning device of the present invention uses a conductive brush instead of a coronatron to remove static electricity from a charged traveling dielectric material or reverse the static charge, thereby eliminating the generation of gases such as ozone. Moreover, the cleaning properties are also good. Furthermore, it has the advantage of being smaller than a cleaning device using a coronatron.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of the configuration of a cleaning device according to an embodiment of the present invention, Fig. 2 is a schematic side view showing the application of the glue cleaning device of the present invention to a laser printer, and Fig. 3 is a fixed conductive brush. 2 is a graph showing the relationship between the voltage applied to the conductive brush and the surface potential of the belt-shaped dielectric immediately after passing through the fixed conductive brush. 1... Running dielectric, 1a... Dielectric layer, 1b... Conductive layer, 2... Fixed conductive brush, 3...・Toner, 4...Rotating conductive brush, 5...Collection loft, 6...
... Scraping blade, 7 ... Toner collection box, 8.9 ... Power supply, 10 ... Case, 20 ... Cleaning device. Name of agent: Patent attorney Toshio Nakao Haka1 person 1-, a:
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Claims (1)

[Claims] In a copying machine, a conductive brush is applied with a voltage having a polarity opposite to the charged polarity of the toner and rotates in contact with the running dielectric, for removing toner adhering to the running charged dielectric. , a polarity voltage that is installed close to the dielectric surface on the upstream side of the traveling dielectric as viewed from the brush and that eliminates the charge on the dielectric or converts the charged polarity of the dielectric to the opposite polarity; A cleaning device comprising a fixed conductive brush to which is applied.