Electrophotography – Cleaning of imaging surface – Including lubricant
Reexamination Certificate
2000-08-24
2001-12-11
Grainger, Quana M. (Department: 2852)
Electrophotography
Cleaning of imaging surface
Including lubricant
Reexamination Certificate
active
06330420
ABSTRACT:
BACKGROUND OF THE INVENTION
This application is based on application No. 275045/1999 filed in Japan, the contents of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates generally to an image forming apparatus such as an electrophotographic copying machine or a printer, and more particularly, to an image forming apparatus so adapted as to supply toners to an image carrying member from a developing device, form a toner image on a surface of the image carrying member, transfer the toner image to a recording medium from the image carrying member, press a pressing member against the surface of the image carrying member after the transfer, and remove the toners remaining on the surface of the image carrying member, characterized in that the pressing member is prevented from immediately wearing and causing irregularities in the surface of the image carrying member, to stably remove the toners remaining on the surface of the image carrying member.
2. Description of the Related Art
In a conventional example of image forming apparatuses such as electrophotographic copying machines or printers, an image carrying member
10
in which a photoreceptor
12
is formed on a surface of a conductive base member
11
in a drum shape is rotated, a surface of the image carrying member
10
is charged by a charging device
20
, and the surface of the image carrying member
10
is then subjected to exposure corresponding to image information by a latent image forming device
30
using a laser or the like, to form an electrostatic latent image on the surface of the image carrying member
10
, as shown in FIG.
1
. Toners
41
are supplied to the surface, on which the electrostatic latent image has been thus formed, of the image carrying member
10
from a developing device
40
, to form a toner image corresponding to the electrostatic latent image on the surface of the image carrying member
10
.
Thereafter, a recording medium
51
such as a recording paper sheet is introduced into a portion between the image carrying member
10
and a transferring device
50
such as a transfer roller by a feed roller
52
, to transfer the toner image formed on the surface of the image carrying member
10
to the recording medium
51
by the transferring device
50
.
The toner image which has been thus transferred to the recording medium
51
is then fixed to the recording medium
51
by a fixing device
60
such as a fixing roller. On the other hand, a pressing member
70
in a plate shape is pressed against the surface of the image carrying member
10
after the transfer, to remove the toners
41
or the like remaining on the surface of the image carrying member
10
from the surface of the image carrying member
10
. Thereafter, the surface of the image carrying member
10
is charged by the charging device
20
, as described above. The above-mentioned operations are repeated, to successively form toner images.
When the pressing member
70
is pressed against the surface of the image carrying member
10
, to remove the toners
41
or the like remaining on the surface of the image carrying member
10
from the surface of the image carrying member
10
, as described above, the pressing member
70
which is pressed against the image carrying member
10
gradually wears, so that the toners
41
or the like remaining on the surface of the image carrying member
10
cannot be sufficiently removed. Further, the pressing member
70
causes irregularities in the surface of the image carrying member
10
. The irregularities prevent the toners
41
or the like from being suitably removed by the pressing member
70
. Consequently, noise based on insufficient cleaning appears in the formed toner image.
In recent years, in supplying a lubricant to the surface of the image carrying member
10
and passing the lubricant through the pressing member
70
, the lubricant has been rolled by the pressing member
70
, to form a film of the lubricant on the surface of the image carrying member
10
. The film of the lubricant has prevented the pressing member
70
from wearing and causing irregularities in the surface of the image carrying member
10
.
In the conventional example, in supplying the lubricant to the surface of the image carrying member
10
, the lubricant is added to the toners
41
in the developing device
40
, and the lubricant, together with the toners
41
, is supplied to the surface of the image carrying member
10
, as in the image forming apparatus shown in FIG.
1
. Alternatively, the lubricant is scraped off a molding
81
of the lubricant by a brush
82
, and the lubricant is supplied to the surface of the image carrying member
10
from the brush
82
, as shown in FIG.
2
.
When the lubricant is added to the toners
41
, as described above, however, the performance of the toners
41
changes depending on the type of the lubricant. Consequently, a good toner image cannot be obtained.
When the lubricant, together with the toners
41
, is supplied to the surface of the image carrying member
10
, in a state where the toners
41
or the like remaining on the surface of the image carrying member
10
after the transfer are removed from the surface of the image carrying member
10
by the pressing member
70
, the toners
41
, a post-treatment agent added to the toners
41
, and so forth are stored in a contact portion between the pressing member
70
and the image carrying member
10
. In the portion where the toners
41
, the post-treatment agent, and so forth are stored, the lubricant is not introduced into the pressing member
70
. Accordingly, the film of the lubricant is not satisfactorily formed on the surface of the image carrying member
10
. Consequently, the pressing member
70
still wears and causes irregularities in the surface of the image carrying member
10
.
In scraping the lubricant off the molding
81
of the lubricant by the brush
82
and supplying the lubricant to the surface of the image carrying member
10
, as described above, the lubricant is always supplied to the surface of the image carrying member
10
by the brush
82
in the conventional example.
In a state where the toner image is formed, however, the toners
41
, the post-treatment agent, and so forth are stored in the contact portion between the pressing member
70
and the image carrying member
10
, as described above. Accordingly, the film of the lubricant is not satisfactorily formed on the surface of the image carrying member, as in the above-mentioned case. Consequently, the lubricant is uselessly consumed.
When the lubricant is scraped off the molding
81
of the lubricant by the brush
82
and is supplied to the surface of the image carrying member
10
, as described above, the particle diameter of the lubricant supplied to the surface of the image carrying member
10
by the brush
82
is not fixed. Accordingly, the lubricant having a large particle diameter, together with the toners
41
, is removed from the surface of the image carrying member
10
by the pressing member
70
. On the other hand, the lubricant
70
having a small particle diameter is not satisfactorily rolled by the pressing member
70
. Consequently, the film of the lubricant is not suitably formed on the surface of the image carrying member
10
.
Furthermore, in scraping the lubricant off the molding
81
of the lubricant by the brush
82
and supplying the lubricant to the surface of the image carrying member
10
, as described above, if the diameter of the image carrying member
10
to be used is small, the places where the brush
82
and the molding
81
of the lubricant are provided are a problem.
SUMMARY OF THE INVENTION
A first object of the present invention is to provide an image forming apparatus for supplying toners to an image carrying member from a developing device to form a toner image on a surface of the image carrying member, transferring the toner image to a recording medium from the image carrying member, and pressing a pressing member against the surface of the image carrying member after
Grainger Quana M.
McDermott & Will & Emery
Minolta Co. , Ltd.
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