Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – To produce color reproduction
Reexamination Certificate
2001-07-06
2003-03-25
Chapman, Mark A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
To produce color reproduction
C430S046400, C399S223000, C399S299000
Reexamination Certificate
active
06537714
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an image-forming method and an image-forming apparatus which are applicable to laser beam color printers and color copying apparatus, and more particularly to a high-speed full-color image-forming method and image-forming apparatus therefor.
2. Related Background Art
As photosensitive members used conventionally in image-forming apparatus of this type are roughly grouped into organic members and inorganic members, as exemplified by OPC photosensitive members and a-Si photosensitive members. These techniques are described below.
Organic Photoconductor (OPC) Photosensitive Member
In recent years, as photoconductive materials for electrophotographic photosensitive members development on various organic photoconductive materials has advanced, and especially function-separated photosensitive members having a charge generation layer and a charge transport layer which are superposed have already been put into practical use and are set in copying machines and laser beam printers.
In these photosensitive members, however, it has been considered to be a problem that they commonly have a low durability. The durability is roughly grouped into durability on electrophotographic physical properties (i.e., running performance) concerning sensitivity, residual potential, charging performance and faint images (blurred image), and mechanical durability concerning wear and scratches of photosensitive member surfaces which are caused by rubbing.
Of these, with regard to the durability on electrophotographic physical properties (running performance), in particular, faint images, are known to be caused by deterioration of charge-transporting materials contained in photosensitive member surface layers which are due to active substances such as ozone and NOx generated from corona charging assemblies.
With regard to the mechanical durability, it is known to be caused by paper, cleaning members (such as a blade or a roller) and toners which come into contact with, and rub against, photosensitive layers.
In order to improve the the durability on electrophotographic physical properties (running performance), it is important to use charge-transporting materials that may be deteriorated with difficulty by the active substances such as ozone and NOx. It is known to select charge-transporting materials having a high oxidation potential.
In order to improve the mechanical durability, it is important to make the surface have a high lubricity and a low friction in order to withstand the rubbing with paper and cleaning members, and also to make the surface have good releasability in order to prevent toners from causing filming melt adhesion. It is known to incorporate surface layers with lubricating materials such as fluorine resin powder, fluorinated graphite and polyolefin resin powder.
If, however, the surface may extremely less wear, any moisture-absorptive substances produced by the active substances such as ozone and NOx may accumulate on the photosensitive member surface. As the result, the surface resistance lowers to make surface electric charges move in lateral directions to cause faint images (smeared images) in some cases.
Inorganic Photoconductor: Amorphous Silicon (a-Si) Photosensitive Member
In electrophotography, photoconductive materials that form photosensitive layers in photosensitive members are required to be highly sensitive, have a high SN ratio [light current (Ip)/dark current (Id)], have absorption spectra suited to spectral characteristics of irradiation light or electromagnetic waves, have a high response to light, have the desired dark resistance value and are harmless to human bodies when used. In particular, in the case of photosensitive members for image-forming apparatus, set in image-forming apparatus used in offices as business machines, the harmlessness in their use is an important point.
Photoconductive materials having good properties in these respects include amorphous silicon hydrides (hereinafter “a-Si:H”). For example, Japanese Patent Publication No. 60-35059 discloses its application in photosensitive members for image-forming apparatus.
Now, the layer construction of photosensitive members is described with reference to
FIGS. 3A
to
3
D, which diagrammatically illustrate the layer construction of photosensitive members used in image-forming apparatus. The following description is a general description of photosensitive members. Hence, it is a description on the background art and at the same time it is applicable also to photoconductive members usable in the image-forming apparatus of the present invention. Also, the layer construction of photosensitive members shown in
FIGS. 3A
to
3
D shows a first example to a fourth example of the layer construction of photosensitive members used in the present invention and in conventional-image-forming apparatus.
A photosensitive member
1100
for image-forming apparatus as shown in
FIG. 3A
has a photosensitive member support
1101
and a photosensitive layer
1102
provided thereon. The photosensitive layer
1102
is formed of a-Si:H,X and is constituted of a photoconductive layer
1103
having photoconductivity.
A photosensitive member
1100
for image-forming apparatus as shown in
FIG. 3B
has a photosensitive member support
1101
and a photosensitive layer
1102
provided thereon. The photosensitive layer
1102
is formed of a-Si:H,X and is constituted of a photoconductive layer
1103
having photoconductivity and an amorphous silicon surface layer
1104
.
A photosensitive member
1100
for image-forming apparatus as shown in
FIG. 3C
has a photosensitive member support
1101
and a photosensitive layer
1102
provided thereon. The photosensitive layer
1102
is formed of a-Si:H,X and is constituted of a photoconductive layer
1103
having photoconductivity, an amorphous silicon surface layer
1104
and a charge injection block layer
1105
of an amorphous silicon type.
A photosensitive member
1100
for image-forming apparatus as shown in
FIG. 3D
has a photosensitive member support
1101
and a photosensitive layer
1102
provided thereon. The photosensitive layer
1102
is constituted of a photoconductive layer
1103
consisting of a charge transport layer
1106
and a charge generation layer
1107
which are formed of a-Si:H,X, and an amorphous silicon surface layer
1104
.
In
FIGS. 3A
to
3
D, reference numerals
1106
each denote a free surface.
The image-forming apparatus photosensitive members making use of a-Si:H are commonly produced by heating conductive supports to 50° C. to 400° C. and forming photosensitive layers comprised of a-Si, on the supports by a film-forming process such as vacuum deposition, sputtering, ion plating, thermal CVD (chemical vapor deposition), photo-assisted CVD, plasma-assisted CVD (hereinafter “PCVD”). In particular, PCVD (i.e., a process in which material gases are decomposed by direct-current, high-frequency or microwave glow discharge to form a-Si deposited films on supports) is put into practical use as a preferable process.
Japanese Patent Application Laid-Open No. 56-83746 discloses an image-forming apparatus photosensitive member comprising a conductive support and an a-Si photoconductive layer containing halogen atoms as a constituent (hereinafter “a-Si:X”). This publication reports that the incorporation of 1 to 40 atom % of halogen atoms into a-Si enables achievement of a high heat resistance and also electrical and optical properties preferable for a photoconductive layer of an image-forming apparatus photosensitive member.
Japanese Patent Application Laid-open No. 57-115556 also discloses a technique in which, in order to achieve improvements in electrical, optical and photoconductive properties such as dark resistivity, photoconductivity and response to light, service environmental properties such as moisture resistance, and stability with lapse of time, of a photoconductive member having a photoconductive layer constituted of an a-Si deposited film, a surface layer constitute
Iida Wakashi
Kanbayashi Makoto
Kaya Takaaki
Kondo Katsumi
Kotaki Takaaki
Canon Kabushiki Kaisha
Chapman Mark A.
Fitzpatrick ,Cella, Harper & Scinto
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