JPH0229224B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cleaning device for cleaning untransferred residual toner remaining on an image bearing member of an electrophotographic copying machine.

BACKGROUND ART As shown in FIG. 4, a fur brush roll c is rotatably provided in a cleaner housing b disposed facing a belt-shaped image carrier a, and the fur brush roll c moves the image carrier a The residual toner on the fur brush roll c is collected and cleaned, and the toner caught on the fur brush roll c is knocked off by the collision between the frit cover bar d and the fur brush roll c, and is passed through the flow path e and the duct f by a suction source. A brush-type cleaning device is known that sucks in and discharges air together with air.

Problems to be Solved by the Invention Due to the impact force between the fur brush roll c and the frit cover d, toner is fused to the surface of the frit cover d, forming a toner film called toner filming on the surface. The toner film is transferred to the image bearing member a via the fur brush roll c, and finally a toner film is formed on the surface of the image bearing member a, which adversely affects the quality of the copied image.

Means and action for solving the problem
Made from a material of 30 dyne/cm or less to prevent toner film from forming on its surface.

Embodiment FIG. 1 is a cross-sectional view of a fur brush cleaning device. Reference numeral 1 in FIG. , 2' and the backup rolls 3, 3'. 4,
Reference numeral 4' designates a pair of fur brush rolls that are in contact with the image carrier 1 and whose rotating shafts are perpendicular to the moving direction of the image carrier 1. It is made up of approximately 2000 acrylic fibers/cm ² flocked on the surface, and the
It is designed to rotate at 1200 rpm. 5,5'
is the first covering the fur brush rolls 4, 4';
The second housings 6, 6' serve to knock off toner particles adhering to the brush fibers of the fur brush rolls 4, 4'. The first and second housings are removably attached to opposite ends of the frit cover bars 6 and 6' with bolts to improve ease of maintenance and inspection. A suction port 7 is formed which opens into the insides of the holes 5 and 5'.

This suction port 7 is connected to a duct 9 via a flow path 8, and this duct 9 is connected via a hose (none of which is shown) to a dust collector having a vacuum source.

The frit cover 6, 6' is made of a material having a critical surface energy of 30 dyne/cm or less, such as Teflon-based polytetrachloroethylene (PTFE), fluoroethylene propylene (FEP), or other resin.

Further, the fur brush rolls 4, 4' are slightly in contact with the first and second housings 5, 5'.

That is, the outer diameter of the fur brush rolls 4, 4' is slightly larger than the inner diameter of the first and second housings 5, 5'.

10 and 10' form slits with high air flow speed between the image carrier 1 and the ends of the first and second housings 5 and 5'.
These are first and second orifice baffles to prevent toner particles inside from leaking out of the cleaning device. 11 is corotron wire 1 for cleaner
This is a pre-cleaning corotron consisting of a corotron shield 13 and a corotron shield 13, and the pre-cleaning corotron 11 generates a current of 400Hz and 0.09 to 0.23 μA.
AC corona irradiation at sec/cm ² and plus DC corona irradiation at 0.046 μA·sec/cm ² are carried out, thereby processing the residual toner image on the image carrier 1 so that it can be easily cleaned.

Note that the polarity of the applied current is opposite to that described above when the image carrier 1 is made of a P-type semiconductor. In the fur brush cleaning device described above, the untransferred toner image remaining on the image carrier 1 is treated with corona irradiation from the pre-cleaning corotron 11 to make it easier to clean, and then is transferred to the fur brush cleaning device. It's coming in. In the fur brush cleaning device, the untransferred toner image is transferred to a pair of rotating fur brush rolls 4,
The toner positively charged by the pre-cleaning corotron 11 is cleaned by the wiping action of 4' and the electrostatic attraction force as follows.

First, since the fur brush rolls 4 and 4' are made of acrylic fiber (in this example, Kanekalon manufactured by Kanegafuchi Chemical Co., Ltd.), they come into contact with the frit cover bars 6 and 6' made of Teflon resin. At the same time as being positively charged by frictional charging, the positive toner is repelled by electrostatic repulsion and is mechanically wiped away (flicking).

Next, the fur brush rolls 4, 4', which are frictionally charged to a positive polarity, are brought into contact with the grounded first and second housings 5, 5' made of metal (aluminum extrusion molded in this embodiment), and thereby the negative polarity is applied. (according to the charge series).

Therefore, the pre-cleaning corotron 11
The positively charged toner is effectively cleaned by the negatively charged fur brush rolls 4, 4' by electrostatic cleaning action and mechanical cleaning action.

Note that the first fur brush roll 4
90% of the toner is cleaned and the remaining 10% of the toner is ensured by the second fur brush roll 4'.

The cleaned toner then collides with the first and second fricker bars 6, 6' and is knocked down from within the fiber.
It scatters into the second housing 5, 5' and reaches a dust collector (not shown) via the suction port 7, flow path 8, duct 9, and hose by a vacuum source, where the toner and air are separated. Ru.

Here, since the first and second frit cover bars 6, 6' are made of a material with a critical surface energy of 30 dyne/cm or less, the fur brush rolls 4, 4'
Even if the toner collides with the toner, the toner will not be fused to the surface.

In other words, the critical surface energy of toner is generally about 30 dyne/cm, and the first and second frit cover bars 6, 6' are made of a material with a critical surface energy smaller than the critical surface energy of the toner.
If you use the toner, the toner will not be fused to the surface.

This was also confirmed by the experiment described below.

That is, an experiment was conducted under the same conditions by changing the material of the frit cover to see if a toner film would form on its surface, and the results shown in the surface of FIG. 2 were obtained.

Therefore, even though it is a fluorocarbon resin, polyvinyl fluorand (PVDF) has a critical surface energy of 40 dyne/cm, which is larger than that of toner, so it forms a toner film, making it unsuitable as a material for frit cover.

Additionally, PC, acrylic (PMMA), polyacetal (POM), Al (deformed material), etc. are also not suitable as materials for fritz covers.

It has been found.

In addition, since fluorine-based resin is relatively easily abraded, the fritz cover bars will wear out quickly. Therefore, the first and second fritz cover bars 6, 6' are detachably attached to the first and second housings 5, 5'. Maintainability is improved by making it easy to replace.

According to experiments, it has been found that it is sufficient to replace it every 1 million copies.

The first and second frit cover bars 6, 6' are
As shown in the figure, the first and second housings 5, 5'
It may be detachably attached by means of a locking piece 21 which is fitted in a snap-fitting manner to a locking receiving piece 20 fixed to the opposite end of the locking member.

Effects of the invention Toner is not fused to the surface of the frit cover by the collision force of the fur brush roll.
Since no toner film is formed on the surface, the cleaning device has good cleaning performance over a long period of time and does not have any adverse effect on the quality of copied images.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a cleaning device showing an embodiment of the present invention, FIG. 2 is a table showing whether a toner film is generated depending on the material of the frit cover, FIG. The figure is a sectional view of a conventional example. 1 is an image carrier, 4 and 4' are fur brush rolls,
5 and 5' are first and second housings, and 6 and 6' are first and second frit cover bars.

Claims (1)

[Scope of Claims] 1. A housing installed such that its opening side faces an image carrier of an electronic copying machine; , a fur brush roll with a fur brush made of acrylic fibers standing upright on its surface; A cleaning device for an electrophotographic copying machine, comprising: a frit cover made of a fluorocarbon resin material;