Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
2002-01-09
2003-11-25
Goodrow, John (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S075000, C549S074000
Reexamination Certificate
active
06653034
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a novel stilbeneamine derivative and an electrophotosensitive material using the same.
BACKGROUND OF THE INVENTION
As an electrophotosensitive material for use in image forming apparatuses such as electrostatic copiers, laser beam printers, plain paper facsimiles and the like, a so-called organic electrophotosensitive material is widespread which comprises a combination of the following components:
a charge generating material for generating an electric charge (positive hole and electron) when exposed to light;
a charge transport material for transporting the generated electric charge; and
a binder resin.
The charge transport materials fall into two broad categories which include a positive-hole transport material for transporting positive holes of the electric charge, and an electron transport material for transporting electrons.
The organic electrophotosensitive material has an advantage over an inorganic electrophotosensitive material employing an inorganic semiconductor material in that the organic electrophotosensitive material is fabricated more easily at less production costs than the latter.
In addition, the organic electrophotosensitive material also has a merit of greater freedom of function design by virtue of a wide variety of options for materials including charge generating materials, charge transport materials, binder resins and the like.
In this connection, the organic electrophotosensitive materials have recently been widely used in the image forming apparatuses.
Unfortunately, however, the organic electrophotosensitive materials are inferior to the inorganic electrophotosensitive materials in photosensitivity and in electrical stability in the course of repeated image forming cycles, or in other words, repeatability.
With an aim at solving the above problem, intensive study has been made on the improvement of various materials for use in the organic electrophotosensitive materials. The charge transport material, in particular, is an important material affecting not only the sensitivity but also the repeatability of the electrophotosensitive material.
Japanese Laid-open Patent Publication JP 02-12256 A (1990) discloses a charge transport material of stilbeneamine derivative represented by a formula (2):
wherein Ar
1
denotes an aryl group or heterocyclic group, each optionally having a substituent; Ar
2
and Ar
3
are the same or different, each denoting an arylene group; and R
1
and R
2
each denote an alkyl group, aralkyl group or aryl group, each optionally having a substituent; provided that Ar
3
and R
1
or Ar
3
, R
1
and R
2
may be combined together to form a heterocycle. Incidentally, the patent publication cites quinolyl, carbazolyl, oxazolyl and imidazolyl as the heterocyclic group represented by Ar
1
.
Alternatively, Japanese Laid-open Patent Publication JP 58-123542 A (1983) discloses a stilbeneamine derivative which is represented by a formula (3):
wherein X
1
and X
2
are the same or different, each denoting a phenyl group optionally having a substituent; X
3
denotes an arylene group optionally having a substituent; and X
4
denotes an aryl group, 2-furil group, or 2-thienyl group, each optionally having a substituent.
There is further disclosed in Japanese Laid-open Patent publication JP 09-134021 A (1997) a stilbeneamine derivative represented by a formula (4):
wherein R
a
, R
b
, R
c
, R
d
and R
e
each denote a hydrogen atom, halogen atom, alkyl group, aryl group or alkoxy group; and x denotes an integer of 0 to 2.
However, the inventors have examined the stilbeneamine derivatives disclosed in the above official gazettes to find that all these compounds suffer the following problems:
that they still fall short of achieving sufficient compatibility with the binder resin to be uniformly dispersed in the photosensitive layer, thus suffering a low tendency of producing electric charge transfer;
that they are still short of electric charge transferring capability;
that they suffer insufficient in electrical, physical and chemical stabilities; and
that as a consequence, the electrophotosensitive materials comprising these compounds are not only sufficiently improved in photosensitivity but also suffer poor repeatability.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a novel stilbeneamine derivative which has a larger electric charge mobility than the prior-art compounds, thus featuring excellent electric charge transferring capability and which is also excellent in compatibility with the binder resin and in stability.
It is another object of the invention to provide an electrophotosensitive material using the above stilbeneamine derivative and featuring excellent sensitivity and repeatability.
For achieving the above objects, the inventors have conducted analysis on the structure of a stilbeneamine derivative represented by a formula (1):
wherein R
1
denotes an alkyl group, alkoxy group, aryl group, aralkyl group, halogen atom or hydrogen atom; Ar
1
and Ar
2
are the same or different, each denoting an aryl group; Ar
3
denotes an arylene group; and Ar
4
denotes an arylene group or divalent heterocyclic group.
Finally, the inventors have discovered that the above objects can be achieved by limiting In, in the formula to 1 when a terminal thiophene ring of the stilbeneamine derivative is 2-thienyl or by limiting ‘n’ to 0 or 1 when the terminal thiophene ring is 3-thienyl.
That is, the stilbeneamine derivative of the invention is represented by the formula (1):
wherein R
1
denotes an alkyl group, alkoxy group, aryl group, aralkyl group, halogen atom or hydrogen atom; Ar
1
and Ar
2
are the same or different, each denoting an aryl group; Ar
3
denotes an arylene group; and Ar
4
denotes an arylene group or divalent heterocyclic group; provided that when a thiophene ring in the formula is 2-thienyl, ‘n’ is 1 whereas when the thiophene ring is 3-thienyl, ‘n’ is 0 or 1.
The stilbeneamine derivative represented by the formula (1) is absolutely a novel compound which is not specifically described in any of the above official gazettes.
If the stilbeneamine derivative of the formula (1) is compared with a compound represented by the formula (2) and defined as Ar
1
being an aryl group such as a phenyl group, the former is more improved in compatibility with the binder resin than the latter. This is because the thienyl group has a higher degree of asymmetry in terms of molecular structure and electrical property than the aryl group.
The thienyl group has a higher electron donatability than the aryl group and the other heterocyclic groups (such as the aforesaid quinolyl, carbazolyl, oxazolyl, imidazolyl and the like). Thus, the stilbeneamine derivative of the formula (1) is superior to the compounds of the formula (2) in electric charge transferring capability, as well.
If, out of the stilbeneamine derivatives of the formula (1), a compound having 3-thienyl group as the thiophene ring and defined as ‘n’ being 0 is compared with a compound represented by the formula (3) and having 2-thienyl group as X
4
or a compound represented by the formula (4) and defined as ‘x’ being 0, the former has a larger ionization potential than the latter ones. Thus, the former stilbeneamine derivative is particularly more improved in electrical stability than the latter compounds.
If, out of the stilbeneamine derivatives of the formula (1), a compound having 2-thienyl group or 3-thienyl group as the thiophene ring and defined as ‘n’ being 1 is compared with the compound of the formula (3), the former has a larger spread of &pgr;-electron conjugated system than the latter because of the presence of —CH═CH—Ar
4
— at the molecular center. Thus, the former stilbeneamine derivative is superior to the compound of the formula (3) in electric charge transferring capability. Furthermore, the former stilbeneamine derivative is more excellent in stability than the latter, because of the greater molecular weight of the basic skeleton.
If, out of the stilbeneamine derivatives of the formula (1), the c
Inagaki Yoshio
Kuboshima Daisuke
Goodrow John
Kyocera Mita Corporation
Smith , Gambrell & Russell, LLP
LandOfFree
Stilbeneamine derivative and electrophotosensitive material... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Stilbeneamine derivative and electrophotosensitive material..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stilbeneamine derivative and electrophotosensitive material... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3170033