Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
2001-03-16
2003-07-01
Dote, Janis L. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S069000, C430S111400, C430S124300, C430S132000, C399S159000
Reexamination Certificate
active
06586149
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a light-receiving member, an image-forming apparatus and an image-forming method. More particularly, it relates to a light-receiving member having a photosensitive layer used to form an electrostatic latent image thereon, an image-forming apparatus having the light-receiving member, and an image-forming method making use of the light-receiving member.
2. Related Background Art
(1) Image-Forming Apparatus
A number of methods as disclosed in U.S. Pat. Nos. 2,297,692, 3,666,363 and 4,071,361 are conventionally known as electrophotography. In general, copies are obtained by forming an electrostatic latent image on an light-receiving member (e.g., an electrostatic latent image bearing member) by utilizing a photoconductive material and by various means, subsequently developing the latent image by the use of a toner to form a toner image, transferring the toner image as a developed image to a transfer medium such as paper as occasion calls, and then fixing the toner image by the action of heat, pressure, or heat and pressure, or solvent vapor. In the course of the foregoing, untransferred toner remains on the light-receiving member even after the toner image has been transferred to the transfer medium, and hence such untransferred toner has ever been collected through a cleaning step and put away outside the system as waste toner.
With an increase in the throughput of information in recent years, there is a more increasing demand for image-forming apparatus such as copying machines and laser beam printers having a large copying volume (i.e., large-sized high-speed machines).
As light-receiving members, light-receiving member performances adapted to high-speed are required to be improved. At the same time, in these days where more minute image quality is demanded, toners have been directed toward smaller particle diameters, not to speak of improvements in light-receiving member performances, and those having a weight-average particle diameter of from 5 to 11 &mgr;m as measured by COULTER Counter or the like are in wide use.
Meanwhile, in order to improve cleaning performance, contrived are a blade with grooves as disclosed in Japanese Patent Application Laid-open No. 54-143149 and a blade with projections as disclosed in Japanese Patent Application Laid-open No. 57-124777. These publications, however, do not refer to any cleaning system suited for image-forming apparatus having a process speed of 400 mm/sec or higher and comprising a fine-particle toner improved in fixing performance and an a-Si (amorphous silicon) light-receiving member.
FIG. 1
is a schematic view for describing an example of an image-forming process in a copying machine which is a kind of the image-forming apparatus. Here is given a diagrammatic cross-sectional view of the construction of the image-forming apparatus.
A light-receiving member
101
is rotated in the direction of an arrow X. The light-receiving member
101
is formed in a drum, and is provided with a sheet-like inner-surface heater
123
on the drum inside, by means of which the light-receiving member
101
is temperature-controlled. Around the light-receiving member
101
, it is provided with a charging means primary charging assembly
102
, an electrostatic latent image forming portion
103
, a developing means developing assembly
104
, a transfer paper feed system
105
, a transfer means transfer charging assembly
106
(
a
), a separation charging assembly
106
(
b
), a cleaner
125
, a transport system
108
and a destaticizing light source
109
.
An image-forming process is described below by further giving a specific example. The light-receiving member
101
is uniformly electrostatically charged by means of the primary charging assembly
102
, to which a high voltage of from +6 to +8 kV is kept applied. Light emitted from a halogen lamp
110
reflects from an original
112
placed on an original glass plate
111
and travels via mirrors
113
,
114
and
115
, and an optical image is formed by a lens
118
of a lens unit
117
. The optical image is guided via a mirror
116
to the electrostatic latent image forming portion and projected on the light-receiving member
101
, thus an electrostatic latent image is formed on the light-receiving member
101
. To this latent image, a toner for developing electrostatic latent images is supplied from the developing assembly
104
, and the latent image is formed into a developed image made visible (hereinafter also “toner image”).
Meanwhile, a transfer material P is fed toward the light-receiving member
101
via the transfer paper feed system
105
while its leading end is timing-controlled by means of a registration roller
122
. To the transfer material P, an electric field having a polarity opposite to that of the toner is imparted from the side of the transfer charging assembly
106
(
a
) at a gap formed between the transfer charging assembly
106
(
a
) to which a high voltage of from +7 to +8 kV is kept applied and the light-receiving member
101
. Thus, the toner image held on the surface of the light-receiving member
101
is transferred to the transfer material P. The transfer material P is separated from the light-receiving member
101
by means of the separation charging assembly
106
(
b
), to which a high AC voltage is kept applied at a peak-to-peak voltage of from 12 to 14 kVp-p and a frequency of from 300 to 600 Hz, and is made to pass the transport system
108
to come to a fixing assembly
124
. The transfer material P is, after the toner image held thereon has been fixed by means of the fixing assembly
124
, delivered outside the apparatus.
The toner remaining on the light-receiving member
101
is removed from the surface of the light-receiving member
101
by means of a cleaning roller
107
and a cleaning blade
121
which are provided in the cleaner
125
. Any electrostatic latent image remaining on the surface of the light-receiving member
101
is eliminated by means of the destaticizing light source
109
(2) Light-Receiving Member
With regard to techniques for device members used in the light-receiving member, various materials are proposed, such as selenium, cadmium sulfides, zinc oxide, phthalocyanine and amorphous silicon (hereinafter “a-Si”). In particular, non-single-crystal deposited films composed chiefly of silicon atoms as typified by a-Si films, e.g., amorphous silicon deposited films of a-Si compensated with hydrogen and/or a halogen (e.g., fluorine or chlorine) are proposed for light-receiving members having high performance and high durability and causing no environmental pollution, and some of them have put into practical use. As processes for forming such deposited films, a large number of processes are conventionally known, such as sputtering, a process in which material gases are decomposed by heat (heat-assisted CVD), a process in which material gases are decomposed by light (photo-assisted CVD), and a process in which material gases are decomposed by plasma (plasma-assisted CVD). In particular, plasma-assisted CVD, i.e., a process in which material gases are decomposed by glow discharge that utilizes a direct-current or high-frequency (RF or VHF) power or a microwave power to form a thin-film deposited film on an insulating substrate made of glass or quartz or formed of a heat-resistant synthetic resin film, or a substrate having been conductive-treated by providing a metal on the surface of any of these, or a conductive substrate made of stainless steel or aluminum, is preferred in the formation of non-single-crystal silicon films, preferably a-Si deposited films, for light-receiving members.
Proposals are made in variety in order to improve electrophotographic performance of light-receiving members having a photosensitive layer formed of amorphous silicon. For example, Japanese Patent Application Laid-open No. 57-115551 discloses an example of a light-receiving member comprising a photoconductive layer constituted of an amorphous material composed chiefly
Ehara Toshiyuki
Hashizume Junichiro
Karaki Tetsuya
Kawada Masaya
Kawamura Kunimasa
Canon Kabushiki Kaisha
Dote Janis L.
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