Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
2000-08-29
2002-07-02
Goodrow, John (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S127000
Reexamination Certificate
active
06413689
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a porous photosensitive body used for an image recording device such as a copying machine, facsimile, printer or a like and to a method for manufacturing same.
2. Description of the Related Art
As technology of forming an image, for example, in a copying machine, electronic printing technologies including a Carlson process (one of the xerographic methods) are known. In the Carlson process, since printing is made by six processes of charging, exposure, development, transfer, fixation and cleaning and since a unit is to be used specifically for each of the six processes is required, increased size of a printing device, generally, is unavoidable.
To solve this problem, electronic printing technology to substitute as the Carlson method has been disclosed by the applicant of the present invention in Japanese Patent Application Laid-open No. Hei9-204092.
FIG. 19
is a perspective view showing configurations of a porous photosensitive body disclosed in the above patent application. As shown in
FIG. 19
, a porous photosensitive body
192
is composed of a large number of fine holes
191
a
opening on a surface of a layer and an insulating layer
191
having an electrode
191
b
exposed toward an outside which is stacked on a cylindrical body (not shown) used for forming the porous photosensitive body, wherein each of the fine holes
191
a
is filled with conductive coloring grains (toners) on which exposure light corresponding to printing information is irradiated to cause the photosensitive coloring grains to hop and to be selectively transferred through paper to be printed to an electrode
191
b
disposed in an opposed direction at a time of printing. A rotary axis
193
is provided with a flange
193
a
and is rotated in a main scanning direction “a” or in a sub-main scanning direction “b”. By configuring the porous photosensitive body as above, the printing can be completed by three processes including filling with coloring grains, exposure and grain hopping and fixing, thus allowing a printing device to be made compact as a whole. Preferably, the porous photosensitive body is of a cylindrical shape or of a jointless sheet shape so that consecutive printing can be performed. Planar shape of the fine holes
191
a
can be round, elliptical, square or honeycomb, whichever may be selected as necessary.
In the porous photosensitive body of this type, to ensure a predetermined image density at the time of printing, a depth of each of the fine holes
191
a
constituting a minimum print unit (one dot), that is, a thickness of the insulating layer
191
is set so as to be comparatively large, while to ensure an image with high resolution, a pitch between two fine holes
191
a
being adjacent to each other is set to be as small as possible.
To fabricate the porous photosensitive body of this type, there is conventionally a method in which a sheet composed of an insulating body having the large number of fine holes
191
a
is wound around a circumferential face of the drum used to form the porous photosensitive body. However, in this method, a joint of the sheet is produced after the sheet is wound, which causes a defect in the image, resulting in reduction in quality of the printed image.
Moreover, there is another method for fabricating the porous photosensitive body of this type, in which, after insulating layers are formed on a circumferential face of a cylindrical drum for forming a photosensitive body, a large number of fine holes are made on an insulating body by using a laser or a drill. However, it is impossible to use this method practically, because only one hole can be made by a one time hole-making operation. For example, when printing with a resolution of 200 dots/inch is to be performed on A4 size paper, a million or more fine holes to be made on the insulating layer of the cylindrical drum with 210 mm in length and 30 mm in diameter are required. Though the large number of fine holes
191
a
can be made also by using the laser, thereby providing a high quality of printed images, is difficult to mass produce and is costly.
To handle these problems, a further method for fabricating the porous photosensitive body is proposed, in which an insulating layer made of a photo-curing liquid resin having cured and non-cured portions corresponding to hole patterns is stacked on a photo-conductive layer from which the non-cured portions have been removed. An insulating layer
201
is formed by such a method as shown in
FIG. 20
which is a cross-sectional view of the conventional porous photosensitive body. That is, as shown in
FIG. 20
, a translucent conductive layer
203
and photo-conductive layer
204
are stacked, in consecutive order, on a circumferential face of a cylindrical translucent supporting body
202
and then a photo-curing liquid resin is coated on a circumferential face of the drum
205
(stacked body).
Moreover, as shown in
FIG. 20
, a pattern of a fine holes
201
a
of the insulating layer
201
is formed by irradiating exposure light along an axial direction while the drum
205
having the insulating layer
201
is being rotated at an angle &thgr; corresponding to a hole pitch in a circumferential direction. Also, as shown in
FIG. 20
, the porous photosensitive body
206
is made of the drum
205
having the insulating layer
201
and
4
surface electrode
207
.
However, the porous photosensitive body obtained by the methods described above has the following problems:
(1) Because the printing is made by irradiating exposure light from an exposure system (not shown) mounted in the cylindrical translucent supporting body
202
, that is, the printing is made by a rear exposure printing method, the translucent supporting body
202
must be formed with high accuracy and therefore this method is not suitable for the mass production thereof.
(2) To achieve the printing with high resolution, it is necessary to perform a highly accurate alignment for a single line or several lines along the axial line of the cylindrical drum. This is because, unless the highly accurate alignment is performed, due to errors in angles occurring in one step being accumulated for each rotation of the drum at the time of exposure, a pitch between an exposure starting end and an exposure terminating end is not matched to one between fine holes
201
a
which causes a portion not to be exposed to be exposed and, due to curing of the resin in this portion, a line in which the fine hole
201
a
is not formed in the direction of the axial line of the drum, that is, a joint is produced. As a result, such additional devices as an angle detecting device, position detecting device or a like are required, which makes costs high.
(3) The fine hole
201
a
(
FIG. 20
) is formed, as shown by
FIG. 21
, by irradiating exposure light corresponding to a hole pattern on an photo-curing liquid resin
211
, which constitutes the insulating layer
201
shown in
FIG. 20
, to cause a cured resin portion
211
a
and a non-cured resin portion
211
b
(a portion to produce a latent image) to be formed and then by removing the non-cured resin portion
211
b
. In this method, if exposure quantity is not adjusted, as shown in
FIG. 22
, a portion constituting the cured resin portion
211
a
is expanded due to halation of the transmitted light
212
a
reaching a groundwork layer
213
(photo-conductive layer
204
in
FIG. 20
) of the photo-curing liquid resin
211
, causing the aperture portion of the fine hole
201
a
to be partially narrowed.
FIG. 23
is a graph showing a relationship between exposure quantity and hardness of the photo-curing liquid resin
211
when the exposure light is irradiated on the insulating layer
201
of the conventional porous photosensitive body
206
. As shown in
FIG. 23
, generally, in a sensitivity curve of the photo-curing liquid resin
211
, as the exposure quantity increases, the hardness of the photo-curing liquid resin
211
increases and, after the exposure quantity exceeds a threshold value,
Funayama Yasuhiro
Hori Takeshi
Uezono Tsutomu
Yoshii Tomoyuki
Goodrow John
NEC Corporation
Whitham Curtis & Christofferson, PC
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