U.S. patent application number 09/770321 was filed with the patent office on 2001-11-22 for image receiving sheet and method of forming ohp image.
Invention is credited to Hayashi, Masafumi, Ikeuchi, Nobuho.
Application Number | 20010044031 09/770321 |
Document ID | / |
Family ID | 26584400 |
Filed Date | 2001-11-22 |
United States Patent
Application |
20010044031 |
Kind Code |
A1 |
Ikeuchi, Nobuho ; et
al. |
November 22, 2001 |
Image receiving sheet and method of forming OHP image
Abstract
The present invention provides an image receiving sheet
applicable to an over head projector (OHP) and a process for
forming an OHP image. The image receiving sheet is capable of
forming a yellow image providing a parallel-ray transmittance (Y)
of 50% or more when the transmittance density (X) is in a range
from 0 to 1.0 by electrophotography. The image receiving sheet is
capable of forming a yellow image providing a haze value (Z) of 40%
or less when the transmittance density (X) is in a range from 0 to
1.0 by electrophotography.
Inventors: |
Ikeuchi, Nobuho; (Tokyo-to,
JP) ; Hayashi, Masafumi; (Tokyo-to, JP) |
Correspondence
Address: |
Timothy J. Keefer
Wildman, Harrold, Allen & Dixon
225 West Wacker Drive
Chicago
IL
60606
US
|
Family ID: |
26584400 |
Appl. No.: |
09/770321 |
Filed: |
January 26, 2001 |
Current U.S.
Class: |
428/411.1 ;
430/31 |
Current CPC
Class: |
Y10T 428/31504 20150401;
G03G 2215/00497 20130101; G03G 7/0006 20130101; G03G 7/00 20130101;
Y10T 428/31786 20150401; Y10T 428/31797 20150401; G03G 15/6591
20130101 |
Class at
Publication: |
428/411.1 ;
430/31 |
International
Class: |
B32B 009/04; G03G
013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 28, 2000 |
JP |
P2000-020446 |
Feb 2, 2000 |
JP |
P2000-024980 |
Claims
What is claimed is:
1. An image receiving sheet printable by electrophotography and
applicable to an overhead projector (OHP), the image receiving
sheet being capable of forming a yellow image providing a
parallel-ray transmittance of 50% or more when the transmittance
density is in a range from 0 to 1.0 by electrophotography.
2. An image receiving sheet according to claim 1, wherein the image
receiving sheet is capable of forming a yellow image providing a
parallel-ray transmittance of 55% or more when the transmittance
density is in a range from 0 to 0.6 by electrophotography.
3. An image receiving sheet according to claim 1, wherein a
receptor layer printable by electrophotography is formed on at
least one side of a substrate film.
4. An image receiving sheet printable by electrophotography and
applicable to an overhead projector (OHP), wherein the following
expression 1 is established between the transmittance density and
the parallel-ray transmittance when the transmittance density is in
a range from 0 to 0.6;Y.gtoreq.{34/(X+1.2)}+57 Expression 1where X
represents the transmittance density and Y represents the
parallel-ray transmittance, provided that
0.ltoreq.X.ltoreq.0.6.
5. An image receiving sheet according to claim 4, wherein a
receptor layer printable by electrophotography is formed on at
least one side of a substrate film.
6. An image receiving sheet printable by electrophotography and
applicable to an overhead projector (OHP), the image receiving
sheet being capable of forming a yellow image providing a haze
value of 40% or less when the transmittance density is in a range
from 0 to 1.0 by electrophotography.
7. An image receiving sheet according to claim 6, wherein the image
receiving sheet is capable of forming a yellow image providing a
haze value of 30% or less when the transmittance density is in a
range from 0 to 0.6 by electrophotography.
8. An image receiving sheet according to claim 7, wherein a
receptor layer printable by electrophotography is formed on at
least one side of a substrate film.
9. An image receiving sheet printable by electrophotography and
applicable to an overhead projector (OHP), wherein the following
expression 3 is established between the transmittance density and
the haze value when the transmittance density is in a range from 0
to 0.6;Z.ltoreq.32-17/(7X+0.6) Expression 3where X represents the
transmittance density and Z represents the haze value, provided
that 0.ltoreq.X.ltoreq.0.6.
10. An image receiving sheet according to claim 9, wherein a
receptor layer printable by electrophotography is formed on at
least one side of a substrate film.
11. A process for forming an OHP image comprising steps of:
providing an image receiving sheet applicable to an overhead
projector (OHP), the image receiving sheet being capable of forming
a yellow image providing a parallel-ray transmittance of 50% or
more when the transmittance density is in a range from 0 to 1.0 by
electrophotography; and printing an image on the image receiving
sheet by electrophotography.
12. A process for forming an OHP image according to claim 11,
wherein the image receiving sheet to be provided is capable of
forming a yellow image providing a parallel-ray transmittance of
55% or more when the transmittance density is in a range from 0 to
0.6 by electrophotography.
13. A process for forming an OHP image comprising steps of:
providing an image receiving sheet applicable to an overhead
projector (OHP), wherein the following expression 1 is established
between the transmittance density and the parallel-ray
transmittance when the transmittance density is in a range from 0
to 0.6;Y.ltoreq.{34/(X+1.2)}+57 Expression 1where X represents the
transmittance density and Y represents the parallel-ray
transmittance, provided that 0.ltoreq.X.ltoreq.0.6; and printing an
image on the image receiving sheet by electrophotography.
14. A process for forming an OHP image comprising steps of:
providing an image receiving sheet applicable to an overhead
projector (OHP), the image receiving sheet being capable of forming
a yellow image providing a haze value of 40% or less when the
transmittance density is in a range from 0 to 1.0 by
electrophotography; and printing an image on the image receiving
sheet by electrophotography.
15. A process for forming an OHP image according to claim 14,
wherein the image receiving sheet to be provided is capable of
forming a yellow image providing a haze value of 30% or less when
the transmittance density is in a range from 0 to 0.6 by
electrophotography.
16. A process for forming an OHP image comprising steps of:
providing an image receiving sheet applicable to an overhead
projector (OHP), wherein the following expression 3 is established
between the transmittance density and the haze value when the
transmittance density is in a range from 0 to
0.6;Z.ltoreq.32-17/(7X+0.6) Expression 3where X represents the
transmittance density and Z represents the haze value, provided
that 0.ltoreq.X.ltoreq.0.6; and printing an image on the image
receiving sheet by electrophotography.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an image receiving sheet
used for recording an image formed by electrophotography, and,
particularly, to an electrophotographic OHP image receiving sheet
capable of restraining a projected image from being grayed when a
color image is projected using an OHP.
[0003] 2. Description of the Related Art
[0004] In recent years, a method of forming a full color image by
mixing either three toners having different colors, specifically,
yellow, magenta and cyan or four toners having different colors,
specifically, black in addition to the above three colors by using
electrophotography has been put to practical use.
[0005] An image receiving sheet used in this electrophotography
generally adopts a structure in which a receptor layer is formed on
a substrate to record and maintain record information such as
characters and images exactly. This image receiving sheet is used
for OHPs (overhead projector) as communicating means used in
lectures, schools, industries, and other explanatory meetings and
exhibitions.
[0006] When a color image formed by electrophotography is projected
by an OHP, such a phenomenon that the projected image is grayed
(exhibits a gray tone) and the range of the reproduction of a tone
is narrowed is observed. This is because a toner stuck to the
smooth image receiving surface of an image receiving sheet is
insufficiently embedded so that the surface is not smoothed and the
toner is swollen granularly and incident light is thereby scattered
during the projection of an OHP whereby a shadow is formed on a
screen.
[0007] As a method used to solve the grayness problem, there is
disclosed a method measuring and defining the molten toner
inclination angle of the receptor surface of an image receiving
sheet with a toner at a fixing temperature of the toner, which is
described in, for example, JP-A No. 5-88400 or JP-A No. 5-197184.
In a method of measuring the molten toner inclination angle, unlike
the fixing condition in an actual recording printer, a toner disk
is formed as a sample and an image receiving sheet and the disk are
placed on a hot plate to measure the molten toner inclination angle
by using an appointed measuring meter. In this method, specific
instruments such as a molding member and a hot plate are required
and it is necessary to take care for the aforementioned
measurement. This method is not practically convenient because of,
for example, dispersion of measured values.
SUMMARY OF THE INVENTION
[0008] Accordingly, it is an object of the present invention to
find an electrophotographic OHP image receiving sheet which has
high tone reproducibility, enables a vivid image and produces no
graying phenomenon in a projected image of OHPs by a simple
measuring method, thereby solving the aforementioned problem.
[0009] According to a first aspect of the present invention, there
is provided an image receiving sheet printable by
electrophotography and applicable to an overhead projector (OHP),
the image receiving sheet being capable of forming a yellow image
providing a parallel-ray transmittance of 50 % or more when the
transmittance density is in a range from 0 to 1.0 by
electrophotography.
[0010] The image receiving sheet is preferably capable of forming a
yellow image providing a parallel-ray transmittance of 55 % or more
when the transmittance density is in a range from 0 to 0.6 by
electrophotography.
[0011] In the first aspect of the present invention, there is also
provided an image receiving sheet printable by electrophotography
and applicable to an overhead projector (OHP), wherein the
following expression 1 is established between the transmittance
density and the parallel-ray transmittance when the transmittance
density is in a range from 0 to 0.6;
Y.gtoreq.{34/(X+1.2)}+57 Expression 1
[0012] where X represents the transmittance density and Y
represents the parallel-ray transmittance, provided that
0.ltoreq.X.ltoreq.0.6.
[0013] In one embodiment of these OHP image receiving sheets, a
receptor layer printable by electrophotography is formed on at
least one side of a substrate film.
[0014] In the first aspect of the present invention, there is also
provided an image forming process capable of projecting an image by
an OHP using any one of the aforementioned image receiving
sheets.
[0015] Specifically, the process of forming an OHP image according
to the first aspect has the characteristics that any one of the
aforementioned image receiving sheets is provided, and an image is
printed on the image receiving sheet by electrophotography.
[0016] According to the above first aspect of the present
invention, the image receiving sheet is simply evaluated on the
basis of the parallel-ray transmittance (JIS K 7105) and
transmittance density (Macbeth TR-924, filter: status A blue (ISO
5-3)) of a sheet on which an image is formed, thereby obtaining an
image receiving sheet which has high tone reproducibility, enables
a high vivid image and produces no graying phenomenon in an
projected image of an OHP with no complicated method.
[0017] According to a second aspect of the present invention, there
is provided an image receiving sheet printable by
electrophotography and applicable to an overhead projector (OHP),
the image receiving sheet being capable of forming a yellow image
providing a haze value of 40 % or less when the transmittance
density is in a range from 0 to 1.0 by electrophotography.
[0018] The image receiving sheet is preferably capable of forming a
yellow image providing a haze value of 30 % or less when the
transmittance density is in a range from 0 to 0.6 by
electrophotography.
[0019] In the second aspect of the present invention, there is also
provided an image receiving sheet printable by electrophotography
and applicable to an overhead projector (OHP), wherein the
following expression 3 is established between the transmittance
density and the haze value when the transmittance density is in a
range from 0 to 0.6;
Z.ltoreq.32-17/(7X+0.6) Expression 3
[0020] where X represents the transmittance density and Z
represents the haze value, provided that 0.ltoreq.X
.ltoreq.0.6.
[0021] In one embodiment of these OHP image receiving sheets, a
receptor layer printable by electrophotography is formed on at
least one side of a substrate film.
[0022] In the second aspect of the present invention, there is also
provided an image forming process capable of projecting an image by
an OHP using any one of the aforementioned image receiving sheets.
Specifically, the process of forming an OHP image according to the
second aspect has the characteristics that any one of the
aforementioned image receiving sheets is provided, and an image is
printed on the image receiving sheet by electrophotography.
[0023] According to the above second aspect of the present
invention, the image receiving sheet is simply evaluated on the
basis of the haze value (using a haze meter manufactured by Nippon
Denshoku Kogyo according to JIS K 7105) and transmittance density
(Macbeth TR-924, filter: status A blue (ISO 5-3)) of a sheet on
which an image is formed, thereby obtaining an image receiving
sheet which has high tone reproducibility, enables a high vivid
image and produces no graying phenomenon in an projected image of
an OHP with no complicated method.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a vertical section showing one embodiment of an
image receiving sheet of the present invention.
[0025] FIG. 2 is a vertical section showing another embodiment of
an image receiving sheet of the present invention.
[0026] FIG. 3 is a vertical section showing a further embodiment of
an image receiving sheet of the present invention.
[0027] FIG. 4 is a graph of the relational formula:
Y.gtoreq.{34/(X+1.2)}+57 when the transmittance density is in a
range from 0 to 0.6 with respect to the parallel-ray transmittance
of a yellow image formed by electrophotography where X represents
the transmittance density and Y represents the parallel-ray
transmittance.
[0028] FIG. 5 is a graph of the relation al formula:
Z.ltoreq.32-17/(7X+0.6) when the transmittance density is in a
range from 0 to 0.6 with respect to the haze value of a yellow
image formed by electrophotography where X represents the
transmittance density and Z represents the haze value.
[0029] FIG. 6 is a graph obtained by plotting data of the
transmittance density and parallel-ray transmittance of each of
Examples and Comparative Examples.
[0030] FIG. 7 is a graph obtained by plotting data of the
transmittance density and haze value of each of Examples and
Comparative Examples.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] Next, the present invention will be explained in more detail
by way of embodiments of an electrophotographic OHP image receiving
sheet. It is to be noted that the image receiving sheet according
to the present invention includes all image receiving sheets used
for transferring and recording a visible image formed by developing
an electrostatic image by using a toner and is not limited to an
image receiving sheet for recording an electrophotograph.
[0032] An embodiment of the present invention will be explained
based on the drawings.
[0033] FIG. 1 is a vertical section showing one embodiment of an
image receiving sheet of the present invention. In this image
receiving sheet, a receptor layer 2 is formed on one surface of a
substrate film 1.
[0034] FIG. 2 and FIG. 3 are vertical sections showing further
embodiments of an image receiving sheet of the present invention.
In the embodiment of FIG. 2, a receptor layer 2 is formed on one
surface of a substrate film 1 and a resistance control layer 3 is
formed on the receptor layer 2.
[0035] In the embodiment of FIG. 3, a receptor layer 2 is formed on
one surface of a substrate film 1, a resistance control layer 3 is
formed on the receptor layer 2 and a resistance control layer 4 is
formed on the other surface of the substrate film 1.
[0036] Also, in the image receiving sheet of the present invention,
a receptor layer may be formed on one surface of a substrate film
and, as required, a resistance control layer may be formed as the
outermost layer of an image receiving surface and/or back surface
and a primer layer may be formed between the receptor layer and the
substrate film and further, a back surface layer may be formed on
the other surface of the substrate film.
[0037] The structure of each section of the electrophotographic OHP
image receiving sheet will be hereinafter explained in order.
Substrate Film
[0038] As the substrate film 1 used in the image receiving sheet of
the present invention, a type made of a thermoplastic resin
provided with transparency, heat resistance, dimensional stability
and rigidity is preferable since the image receiving sheet is used
for an OHP sheet or the like to observe a recorded image by using a
transmitting light. Specifically, a film or sheet made of a
polyethylene terephthalate resin, polycarbonate resin, acrylic
resin, polyvinyl chloride resin, polypropylene resin, polystyrene
resin, polyethylene resin, cellulose diacetate resin or cellulose
triacetate resin in a thickness of about 10 to 250 .mu.m and
preferably about 50 to 150 .mu.m is exemplified. Among these
resins, a polyethylene terephthalate resin, polyvinyl chloride
resin, polypropylene resin or cellulose triacetate resin is more
preferable in view of the above performances.
[0039] Since the image receiving sheet of the present invention is
used for an OHP sheet or the like to observe a recorded image by
using a transmitting light, it is desirable that the parallel-ray
transmittance of the whole structure including the substrate film
and the receptor layer and, further, the resistance control layer,
the primer layer, the back surface layer and the like as required
be 70% or more. If this requirement is fulfilled, an excellent
transmitted image can be obtained.
[0040] It is to be noted that known adhesive treatment such as
primer treatment or corona discharge treatment may be performed on
the surface of the substrate film for the purpose of improving
adhesion to a layer formed on the substrate film.
Image Receiving Surface and Receptor Layer
[0041] The electrophotographic OHP image receiving sheet of the
present invention is used to form an image on the surface of the
substrate film itself or on the surface of the receptor layer by
using electrophotography or similar techniques.
[0042] A receptor layer 2 may be formed on at least one surface of
the substrate film to improve the ability to fix a toner to the
image receiving surface. In the present invention, as to a yellow
image, a fixed relationship as described later must be established
between the transmittance density and the parallel-ray
transmittance or between the transmittance density and the haze
value. Even in the case where the substrate film has toner-fixing
ability, a receptor layer may be formed to control the
transmittance density, the parallel-ray transmittance and the haze
value. A resin having toner-fixing ability and high wettability to
a color toner is used to form a receptor layer.
[0043] In a first aspect of the present invention, the parallel-ray
transmittance of a yellow image portion when the transmittance
density of the yellow image formed by electrophotography is in a
range from 0 to 1.0 is 50% or more. Or the parallel-ray
transmittance of the yellow image portion is 55% or more when the
transmittance density is in a range from 0 to 0.6. Alternatively,
the parallel-ray transmittance is in the range defined by the
following expression 1 when the transmittance density is in a range
from 0 to 0.6 whereby a vivid image having high tone
reproducibility is obtained and an OHP image freed of a graying
phenomenon is obtained.
Y.gtoreq.{34/(X+1.2)}+57 Expression 1
[0044] where X represents the transmittance density and Y
represents the parallel-ray transmittance, provided that
0.ltoreq.X.ltoreq.0.6.
[0045] When the abscissa is X and the ordinate is Y and Y is dotted
according to the relation of the formula Y-[34/(X+1.2)]+57, the
relation is shown by the solid curve in the graph of FIG. 4.
Therefore, the range defined by the expression 1 is the zone above
and including the solid curve.
[0046] When the receptor layer is formed on the substrate film in
the image receiving sheet of the present invention, whether a
graying phenomenon is produced or not in the image projected by an
OHP can be determined in a simple manner by measuring the
parallel-ray transmittance in the condition that a yellow image is
formed on the receptor layer by electrophotography and by
confirming whether the above requirement is satisfied or not.
Namely, even if there is no OHP projector, whether a graying
phenomenon is produced or not can be determined by only measuring
the above parallel-ray transmittance in an image to be projected by
the OHP.
[0047] In the present invention, the values of the parallel-ray
transmittance are those measured by a method prescribed in JIS K
7105 and the values of the transmittance density are those measured
by using a Macbeth TR-924, status A blue filter (ISO 5-3).
[0048] If the parallel-ray transmittance of the yellow image
portion when the transmittance density is in a range from 0 to 1.0
is less than 50%, the tone reproducibility is inferior and the
vividness of an image is deteriorated with the result that a
graying phenomenon is produced in the projected image of an
OBP.
[0049] Also, even if the parallel-ray transmittance of the yellow
image portion when the transmittance density of the yellow image
formed by electrophotography is in a range from o to 0.6 is less
than 55%, the tone reproducibility is inferior and the vividness of
an image is deteriorated with the result that a graying phenomenon
is produced in the projected image of an OHP like the above
case.
[0050] Also, if the parallel-ray transmittance of the yellow image
portion when the transmittance density of the yellow image formed
by electrophotography is in a range defined by the following
expression 2 when the transmittance density is in a range from 0 to
0.6, the tone reproducibility is inferior and the vividness of an
image is deteriorated with the result that a graying phenomenon is
produced in the projected image of an OHP.
Y<{34/(X+1.2)}+57 Expression 2
[0051] where X represents the transmittance density and Y
represents the parallel-ray transmittance, provided that
0.ltoreq.X.ltoreq.0.6.
[0052] In a second aspect of the present invention, the haze value
when the transmittance density of a yellow image formed by
electrophotography is in a range from 0 to 1.0 is 40% or less. Or
the haze value of the yellow image portion is 30% or less when the
transmittance density is in a range from 0 to 0.6. Alternatively,
the haze value is in the range defined by the following expression
3 when the transmittance density is in a range from 0 to 0.6
whereby a vivid image having high tone reproducibility is obtained
and an OHP image freed of a graying phenomenon is obtained.
Z.ltoreq.32-17/(7X+0.6) Expression 3
[0053] where X represents the transmittance density and Z
represents the haze value, provided that 0.ltoreq.X.ltoreq.0.6.
[0054] When the abscissa is X and the ordinate is z and z is dotted
according to the relation of the formula Z=32-17/(7X+0.6), the
relation is shown by the solid curve in the graph of FIG. 5.
Therefore, the range defined by the expression 3 is the zone below
and including the solid curve.
[0055] When the receptor layer is formed on the substrate film in
the image receiving sheet of the present invention, whether a
graying phenomenon is produced or not in the image projected by an
OHP can be determined in a simple manner by measuring the haze
value and the transmittance density in the condition that a yellow
image is formed on the receptor layer by electrophotography and by
confirming whether the above requirement is satisfied or not.
Namely, even if there is no OHP projector, whether a graying
phenomenon is produced or not can be determined by only measuring
the above haze value in an image to be projected by an OHP.
[0056] In the present invention, the values of the haze value are
those measured by using a haze meter manufactured by Nippon
Denshoku Kogyo according to a method prescribed in JIS K 7105 and
the values of the transmittance density are those measured by using
a Macbeth TR-924, status A blue filter (ISO 5-3).
[0057] If the haze value of the yellow image portion when the
transmittance density is in a range from 0 to 1.0 exceeds 40%, the
tone reproducibility is inferior and the vividness of an image is
deteriorated with the result that a graying phenomenon is produced
in the projected image of an OHP.
[0058] Also, even if the haze value of the yellow image portion
when the transmittance density is in a range from 0 to 0.6 exceeds
30%, the tone reproducibility is inferior and the vividness of an
image is deteriorated with the result that a graying phenomenon is
produced in the projected image of an OHP like the above case.
[0059] Also, if the haze value of the yellow image portion when the
transmittance density is in a range defined by the following
expression 4 when the transmittance density is in a range from 0 to
0.6, the tone reproducibility is inferior and the vividness of an
image is deteriorated with the result that a graying phenomenon is
produced in the projected image of an OHP.
Z>32-17/(7X+0.6) Expression 4
[0060] where X represents the transmittance density and Z
represents the haze value, provided that 0.ltoreq.X.ltoreq.0.6.
[0061] In order to allow the parallel-ray transmittance or haze
value of a yellow image formed by electrophotography to fall in the
range defined in the present invention, examples of the resin
forming the receptor layer include polyolefin resins such as a
polyethylene and polypropylene; vinyl resins such as a polyvinyl
chloride, polyvinylidene chloride, polyvinyl acetate, vinyl
chloride/vinyl acetate copolymer, polyacrylate and polystyrene;
polyester obtained by condensation-polymerizing a diol having a
bisphenol skeleton or an alkylene skeleton with a divalent or
trivalent carboxylic acid or its modification; polyamide type
resin; copolymer of a polyolefin such as polyethylene or
polypropylene and other vinyl monomer; ionomer; cellulose type
resin such as ethyl cellulose and cellulose acetate; polycarbonate
resin; epoxy resin; and phenoxy resin.
[0062] As these binder resins for the receptor layer, those having
a softening point of 30.degree. C. or more and 200.degree. C. or
less are preferably used. Binder resins having a softening point
less than 30.degree. C. are undesirable in view of preservation
ability. Specifically, when image receiving sheets are stuck on
each other, the so-called blocking phenomenon that the receptor
layer adheres to the contact surface tends to be produced. On the
other hand, if the softening point exceeds 200.degree. C., this
requires large energy when an image is formed (fixed) and is
therefore undesirable.
[0063] Because a polyester resin having a bisphenol A skeleton is
frequently used as a binding resin for a toner in general,
particularly a polyester resin or its modified product is
preferably used for the binder of the receptor layer in view of
compatibility, fixing ability and the like.
[0064] A polyester resin to be used in the receptor layer may be
prepared by condensation-polymerizing divalent alcohol components
with dicarboxylic acids. Examples of a divalent alcohol component
include a diol component of bisphenol A modified using ethylene
glycol or propylene glycol. Examples of a divalent alcohol
component further include ethylene glycol, neopentyl glycol,
propylene glycol and trimethylene glycol. Examples of a
dicarboxylic acid include an aromatic dicarboxylic acid such as
terephthalic acid, isophthalic acid and phthalic acid and an
aliphatic dicarboxylic acid such as adipic acid, oxalic acid,
succinic acid, fumaric acid, maleic acid, sebacic acid and moronic
acid.
[0065] Polyester resins exemplified above preferably have a number
average molecular weight ranging from 1,500 to 7,000 regardless of
the type of structural component. When the molecular weight is
excessively small, the resin is too soft, so that when the image
receiving sheets are stuck on each other, the receptor layer
adheres to the contact surface and tends to cause blocking. On the
other hand, when the molecular weight is excessively large, the
resin is too hard as the binder resin of the receptor layer and
hence it is decreased in compatibility with a toner, so that the
toner stuck to the image receiving surface is embedded
insufficiently by heating during fixing and is swollen granularly
and incident light is thereby scattered when an image is projected
by an OHP whereby a shadow is formed on a screen, specifically, the
so-called graying phenomenon of the projected image tends to occur
in, particularly, a highlight section.
[0066] The binder resin of the receptor layer as aforementioned is
highly compatible with a binder resin of a toner used for
electrophotographic recording, has good toner-fixing ability and
toner-wettability and brings about excellent image reproducibility.
The binder resin can also control the relationship between the
transmittance density and the parallel-ray transmittance or the
relationship between the transmittance density and the haze value
within a preferable range with respect to a yellow image.
[0067] Namely, the parallel-ray transmittance of a yellow image
portion can be made to be 50% or more when the transmittance
density of the yellow image formed by electrophotography is in a
range from 0 to 0.1, also can be made to be 55% or more when the
transmittance density is in a range from 0 to 0.6, and further can
be made to fall in a range defined by the aforementioned expression
1 when the transmittance density is in a range from 0 to 0.6.
[0068] Alternatively, the haze value of a yellow image portion can
be made to be 40% or less when the transmittance density of the
yellow image formed by electrophotography is in a range from 0 to
0.1, also can be made to be 30% or less when the transmittance
density is in a range from 0 to 0.6, and further can be made to
fall in a range defined by the aforementioned expression 3 when the
transmittance density is in a range from 0 to 0.6.
[0069] Either one or both of an organic filler and an inorganic
filler may be contained in the receptor layer, to the extent that
it has not much effect of decreasing the parallel-ray transmittance
of the receptor layer or raising the haze value of the receptor
layer, to improve the carriage characteristics. Given as examples
of the organic filler are fine particles made of organic resins
including fluororesins such as an ethylene tetrafluoride resin and
ethylene/ethylene tetrafluoride copolymer, polyethylene resins,
polystyrene resins, acrylic resins, polyamide resins and
benzoguanamine resins. On the other hand, given as examples of the
inorganic filler are silica, colloidal silica, alumina, kaolin,
clay, calcium carbonate, talc and titanium dioxide.
[0070] The average particle size of the filler to be contained is
about 0.1 to 30 .mu.m and preferably about 3 to 20 .mu.m. When the
average particle size is less than 0.1 .mu.m, a desired effect is
not obtained whereas when the average particle size exceeds 30
.mu.m, this causes image fault and also causes a decreased
transparent feeling when the resulting sheet is used for an OHP and
is therefore undesirable. Also, the content of the filler is
preferably in a range between 0.1 and 10% by weight based on the
binder resin of the receptor layer. When the content is too large,
the transparency is decreased whereas when the content is too
small, a desired effect of improving carriage ability is not
obtained.
[0071] In addition to the above filler, additives such as various
surfactants, wax and oil may be mixed and used to the extent that
the effect of the present invention is not impaired. The receptor
layer is formed by applying a coating solution containing the
aforementioned resin component, filler and, as required, other
additives by using a known printing means such as gravure printing
or silk screen printing or a known coating means such as gravure
coating in a dry thickness of about 1 to 10 .mu.m.
Back Surface Layer
[0072] The image receiving sheet of the present invention may be
provided with a back surface layer containing a filler or Si groups
on the other surface of the above substrate film according to the
need. The image receiving sheet of the present invention may be
provided with a back surface layer formed on the side provided with
no receptor layer to more improve the carriage characteristics and
to impart curling preventiveness to the receptor layer formed on
the face side of the substrate film. Moreover, if the back surface
layer is provided with the same image receiving capability as the
receptor layer formed on the face side of the substrate film, an
image can be formed irrespective of the surface or back surface, or
on both surfaces of the image receiving sheet.
[0073] For the back surface layer, an acrylic resin, urethane type
resin or thermoplastic resin to which a silicone group is added
such as a silicone-modified acrylic resin, silicone-modified
urethane type resin or silicone-modified polyester type resin may
be used. Further, a graft copolymer having at least one releasable
segment among a polysiloxane segment, carbon fluoride segment and
long-chain alkyl segment on a principal chain of a binder resin
made of an acryl type, vinyl type, polyester type, polyurethane
type, polyamide type or cellulose type resin may be used as a
thermoplastic resin.
[0074] The back surface layer is formed by adding the
aforementioned resin and organic filler or inorganic filler and, as
required, other additives and by applying these components by a
known coating means in the same manner as in the preparation of the
receptor layer. The thickness of the back surface layer is usually
0.01 to 1.0 .mu.m in the dried state. Although a dry thickness of
0.01 to 1.0 .mu.m produces a sufficient effect in many case, it is
preferable to set the dry thickness in the range of about 0.1 to
2.0 .mu.m in the case of controlling the surface electric
resistance.
[0075] To state the filler for the back surface layer, examples of
the organic filler include fillers made of organic resins including
fluororesins such as an ethylene tetrafluoride resin and
ethylene/ethylene tetrafluoride copolymer, polyethylene resins,
polystyrene resins, acrylic resins, polyamide resins and
benzoguanamine resins. On the other hand, as the inorganic filler,
silica, colloidal silica, alumina, kaolin, clay, calcium carbonate,
talc or titanium dioxide may be used.
Resistance Control Layer
[0076] The provision of a resistance control layer on the outermost
position of the image receiving surface and/or the back surface or
between the receptor layer and the substrate film and/or between
the back surface layer and the substrate film ensures that the
antistatic ability and the toner fixing ability can be
well-maintained.
[0077] Given as examples of resistance control materials used in
the resistance control layer are ionic conductive materials, metal
fine particles and conductive polymers having a .pi. electron
conjugate double bond.
[0078] Examples of the ionic conductive material include positive
ion, negative ion and amphoteric ion types, for example, cationic
antistatic agents such as quaternary ammonium salts and polyamine
derivatives, anionic type antistatic agents such as alkyl
phosphates and nonionic antistatic agents such as fatty acid
esters.
[0079] As examples of the metal fine particles, tin oxide
(SnO.sub.2), zinc oxide (ZnO), indium oxide (In.sub.2O.sub.3) and
titanium oxide (TiO.sub.2) may be given. These metal fine particles
may be used either singly or in combinations of two or more. As
such a metal fine particle, those having an average particle size
ranging from 0.01 to 1.0 .mu.m are preferable.
[0080] Also, a dopant may be added to the metal fine particle as
aforementioned according to the need. As the dopant, generally, Sb
(antimony) is used when the metal fine particle is SnO.sub.2, Al
(aluminum) is used when the metal fine particle is ZnO and Sn is
used when the metal fine particle is In.sub.2O.sub.3. The
aforementioned metal oxides may be either singly or in combinations
of different types. Moreover, the above metal oxides may be coated
with SnO.sub.2 or SnO.sub.2 doped with Sb.
[0081] Further, the metal fine particle as aforementioned may be a
needle particle. In this case, a needle particle having a long axis
with a length ranging from 0.1 to 2 .mu.m and an aspect ratio
ranging from 10 to 50 is preferable. The use of such a needle metal
fine particle makes it possible to control the resistance even if
the amount of the needle metal fine particle is smaller than that
of a spherical particle. The transparency of a layer containing the
metal fine particle is therefore improved and the quality of the
transmitted image can be bettered when the image receiving sheet is
used in applications such as OHPs which are used to observe the
recorded image by using transmitting light.
[0082] For the image receiving sheet of the present invention,
preferably used are SnO.sub.2, metal oxide coated with SnO.sub.2 or
SnO.sub.2 doped with Sb, in particular the SnO.sub.2 doped with Sb,
in consideration of the coating suitability of metal particles,
stability in the surface electric resistance, the electric
conduction of metal, cost or the like.
[0083] As to the composition of a coating solution for the layer
containing the aforementioned metal fine particle, it is preferable
to set the weight ratio in terms of the weight of the metal fine
particle/the weight of the thermoplastic resin (binder) within the
range of from 0.2 to 2.0. When the weight ratio of the metal fine
particle/the thermoplastic resin is less than 0.2, the surface
resistance of a layer to be formed is not stabilized because the
amount of the metal fine particle is small. On the other hand, when
the weight ratio of the metal fine particle/the thermoplastic resin
exceeds 2.0, the peculiar color of the metal fine particle is
noticeable, particularly in the case of tin oxide doped with
antimony, which is undesirable. In the case of tin oxide doped with
antimony, a bluish color appears from the surface
conspicuously.
[0084] It is preferable that the above metal fine particle be
subjected to hydrophilic treatment performed on the surface thereof
and be dispersed in an aqueous solution of the binder resin by
adding a surfactant or a known dispersant such as ethylene
glycol.
[0085] Next, examples of the conductive polymer having a .pi.
electron conjugate double bond include a polythiophene,
polyaniline, sulfonated polyaniline, polyacetylene doped
chemically, polyparaphenylene, polyphenylenevinylene,
polyparaphenylene sulfide, polypyrrole chemically polymerized and
doped, heat-treated products produced from phenol resin,
heat-treated product produced from polyamide and heat-treated
products produced from perylenic acid anhydride.
[0086] As the above conductive polymer having a .pi. electron
conjugate double bond, a polyaniline or polythiophene doped with a
sulfonic group is especially useful.
[0087] The above polythiophene has high transparency and is
therefore utilized to produce an image receiving sheet for OHPs. In
the case where the image receiving sheet according to the present
invention must have transparency in particular, the transmittance
of the image receiving sheet for rays can be increased to 70% or
more.
[0088] Further, because such a polythiophene is a polymer and
scarcely bled out from the layer unlike a conventional low
molecular charge control agent, it does not almost cause a sticky
feeling of the image receiving sheet, a reduction in the charge
control ability during storage and contamination (set-off) of the
toner image-receiving layer with the bled-out charge control
agent.
[0089] The aforementioned polythiophene is dissolved or dispersed
in water or a mixed solvent of water and a water-miscible organic
solvent (e.g., methanol, ethanol or acetone) in the presence of a
poly negative ion while partly carrying a positive charge.
Therefore, a layer containing a polythiophene can be formed with
ease by preparing a coating solution containing the polythiophene
such as a coating solution for a charge control layer or a coating
solution for an image receiving layer and by applying the coating
solution on the substrate of the image receiving sheet.
[0090] As the supply source of the poly negative ion, for example,
a polymer sulfonic acid such as a polystyrenesulfonic acid, polymer
carboxylic acid such as a polyacrylic acid or polyphosphoric acid
or alkali salts of them, especially those having a molecular weight
of 2,000 to 500,000 may be used. A preferable poly negative ion is
a polystyrenesulfonic acid. When a dispersion is prepared, it is
preferable that the average particle size of a polythiophene in the
dispersion be made to be 10 .mu.m or less. As the solution or
dispersion containing a polythiophene, commercial products are
available. For example, a product (trademark: Baytron P) is
available from Bayer.
[0091] Also, a sulfonated polyaniline is useful as other conductive
polymer materials having a .pi. electron conjugate structure. The
sulfonated polyaniline is polyanilines doped with a sulfonic group.
The sulfonated polyaniline can be obtained under the trademark of
aqua Pass-01Z as an aqueous solution or a solution of a mixed
solvent of water and an organic solvent from Nitto Chemical
Industry and used in the present invention. These solutions are
yellowish solutions. However, when the concentration is low, they
are almost non-colored. Therefore, these solutions may be used
without any problem though the image receiving sheet must have
transparency when the image receiving sheet is used in applications
such as OHPs which are used to observe the recorded image by using
transmitting light.
[0092] The resistance control layer is formed by applying a coating
solution containing a binder resin and a resistance control
material as major components to the outermost position (the image
receiving surface or the back surface) of the image receiving sheet
or to beneath the receptor layer or the back surface layer by means
of a common coating method using a gravure coater, roll coater or
wire bar, followed by drying.
[0093] The amount to be applied is about 0.001 to 5 .mu.m in terms
of thickness after dried. If the amount is smaller than the above
range, only insufficient charge control ability is obtained. On the
other hand, even if the amount to be applied is larger than the
above range, the above performance is not improved in proportion to
the thickness in any sense and therefore such an amount is not only
economically disadvantageous but also a cause of reduced density of
an image formed in an electrophotographic copying machine or a
printer. So, an amount out of the above range is undesirable.
[0094] It is preferable that the above resistance control layer be
disposed on the outermost position of the image receiving surface
and/or back surface of the image receiving sheet or between the
image receiving layer and the substrate film and/or between the
back surface layer and the substrate film and the content of the
resistance control agent in the resistance control layer and the
amount of the resistance control layer to be applied be controlled,
thereby allowing the surface resistance to fall in a range between
1.times.10.sup.8 to 1.times.10.sup.14 .OMEGA./.quadrature. under
the circumstance of a temperature of 23.+-.2.degree. C. and a
humidity of 50.+-.10% in the condition that the resistance control
layer forms the surface.
[0095] When the surface resistance is lower than 1.times.10.sup.8
.OMEGA./.quadrature., the transfer efficiency is reduced and the
recording density tends to be decreased. When the surface
resistance exceeds 1.times.10.sup.14 .OMEGA./.quadrature. on the
contrary, a discharge phenomenon occurs when the image receiving
sheet is separated from the light-sensitive body after a toner is
transferred. For this phenomenon, the toner is scattered, for
example, leading to the disorder of characters and an image. This
causes reductions in image quality and vividness and also the
occurrence of static electricity and inferior lubricity whereby
carriage defects and adhesion of dusts tend to be caused.
Primer Layer
[0096] The image receiving sheet may be provided with a primer
layer between the receptor layer and the substrate film. The primer
layer improves adhesion between the substrate film and the image
receiving layer, so that the receptor layer is never peeled from
the substrate film, making it possible to prevent the off-set and
the like between the receptor layer and a fixing roller. As the
resin used for the primer layer, for example, an alkyd resin,
polyester resin, polyvinyl acetate resin, vinyl chloride/vinyl
acetate copolymer resin, NBR resin, SBR resin, polyurethane resin,
acrylic resin or polyamide is used independently, or as mixtures,
copolymer products or modified products of these resins. The
modified products are those obtained by copolymerizing or grafting,
for example a monomer containing a hydroxyl group, carboxylic acid
or quaternary ammonium salt to improve adhesiveness and hydrophilic
ability.
[0097] Also, each of these resins may be cross-linked using, for
example, various hardeners such as an epoxy resin, melamine resin
and isocyanate to improve the adhesiveness and film strength of the
primer layer. As a method of forming the aforementioned primer
layer, the same method as used to form the aforementioned receptor
layer may be selected.
[0098] The thickness of the primer layer is preferably 0.01 to 10
.mu.m and more preferably 0.05 to 1.0 .mu.m when it is dried. If
the thickness is too small, only insufficient adhesion is exhibited
whereas if the thickness is too large, the end face of the image
receiving sheet is made to be sticky when it is cut and the
production cost is increased. Therefore, an amount out of the above
range is undesirable.
EXAMPLES
[0099] The present invention will be explained in more detail by
way of examples, in which all designations of parts and % indicate
parts by weight and weight percentage (wt %), respectively, unless
otherwise noted.
[0100] A series of Example A and a series of Example B are shown
hereinbelow. The series of Example A are examples according to the
first aspect of the present invention whereas the series of Example
B are examples according to the second aspect of the present
invention.
Series of Example A
Example A-1
[0101] A receptor layer was formed on one surface of a substrate
film shown below by using a coating solution a1 for a receptor
layer which had the following composition and a resistance control
layer was formed on the receptor layer by using the following
coating solution for a resistance control layer to produce an image
receiving sheet of Example A-1.
[0102] Also, the thickness (dry thickness) of the receptor layer
was set to 2 .mu.m and the thickness of the resistance control
layer was regulated such that the surface resistance of the image
receiving sheet became 1.times.10.sup.10 .OMEGA./.quadrature..
Substrate Film
[0103] Polyethylene terephthalate film 100 .mu.m in thickness
(100-T60, manufactured by Toray)
Coating Solution a1 for Receptor Layer
[0104] Polyester resin (Epicoat 1004, manufactured by Yuka
Shell
1 Epoxy, number average molecular weight: 1,600, softening 30 parts
point: 97.degree. C., Tg: 55.degree. C.) Silica filler (average
particle size: 5 .mu.m) 0.5 parts Methyl ethyl ketone 35 parts
Toluene 35 parts
Coating Solution for Resistance Control Layer
[0105]
2 Cation modified quaternary ammonium salt 1 part Isopropyl alcohol
100 parts
Example A-2
[0106] A receptor layer was formed on one surface of the substrate
film used in Example A-1 by using the following coating solution a2
for a receptor layer and a resistance control layer was formed on
the receptor layer by using the coating solution for a resistance
control layer which was used in Example A-1 to produce an image
receiving sheet of Example A-2.
[0107] Also, the thickness (dry thickness) of the receptor layer
was set to 2 .mu.m and the thickness of the resistance control
layer was regulated such that the surface resistance of the image
receiving sheet became 1.times.10.sup.10 .OMEGA./.quadrature..
Coating Solution a2 for Receptor Layer
[0108]
3 Polyester resin (RV220, manufactured by Toyobo, 30 parts number
average molecular weight: 4,000, Tg: 53.degree. C.) Silica filler
(average particle size: 5 .mu.m) 0.5 parts Methyl ethyl ketone 35
parts Toluene 35 parts
Example A-3
[0109] A receptor layer was formed on one surface of the substrate
film used in Example A-1 by using the following coating solution a3
for a receptor layer and a resistance control layer was formed on
the receptor layer by using the coating solution for a resistance
control layer which was used in Example A-1 to produce an image
receiving sheet of Example A-3.
[0110] Also, the thickness (dry thickness) of the receptor layer
was set to 2 .mu.m and the thickness of the resistance control
layer was regulated such that the surface resistance of the image
receiving sheet became 1.times.10.sup.10 .OMEGA./.quadrature..
Coating Solution a3 for Receptor Layer
[0111]
4 Polyester resin (HP320, manufactured by The Nippon 30 parts
Synthetic Chemical Industry, number average molecular weight:
3,300, softening point: 95.degree. C., Tg: 63.degree. C.) Silica
filler (average particle size: 5 .mu.m) 0.5 parts Methyl ethyl
ketone 35 parts Toluene 35 parts
Comparative Example A-1
[0112] A receptor layer was formed on one surface of the substrate
film used in Example A-1 by using the following coating solution a4
for a receptor layer and a resistance control layer was formed on
the receptor layer by using the coating solution for a resistance
control layer which was used in Example A-1 to produce an image
receiving sheet of Comparative Example A-1.
[0113] Also, the thickness (dry thickness) of the receptor layer
was set to 2 .mu.m and the thickness of the resistance control
layer was regulated such that the surface resistance of the image
receiving sheet became 1.times.10.sup.10 .OMEGA./.quadrature..
Coating Solution a4 for Receptor Layer
[0114]
5 Polyester resin (HP313, manufactured by The Nippon 30 parts
Synthetic Chemical Industry, number average molecular weight:
8,000, softening point: 110.degree. C., Tg: 64.degree. C.) Silica
filler (average particle size: 5 .mu.m) 0.5 parts Methyl ethyl
ketone 35 parts Toluene 35 parts
Comparative Example A-2
[0115] A receptor layer was formed on one surface of the substrate
film used in Example A-1 by using the following coating solution a5
for a receptor layer and a resistance control layer was formed on
the receptor layer by using the coating solution for a resistance
control layer which was used in Example A-1 to produce an image
receiving sheet of Comparative Example A-2.
[0116] Also, the thickness (dry thickness) of the receptor layer
was set to 2 .mu.m and the thickness of the resistance control
layer was regulated such that the surface resistance of the image
receiving sheet became 1.times.10.sup.10 .OMEGA./.quadrature..
Coating Solution a5 for Receptor Layer
[0117]
6 Polyester resin (RV200, manufactured by Toyobo, 30 parts number
average molecular weight: 17,000, softening point: 163.degree. C.,
Tg: 53.degree. C.) Silica filler (average particle size: 5 .mu.m)
0.5 parts Methyl ethyl ketone 35 parts Toluene 35 parts
[0118] Using the image receiving sheets prepared in the above
Examples and Comparative Examples, the parallel-ray transmittance
and transmittance density of a yellow image formed by
electrophotography were measured and also the image quality was
evaluated.
[0119] In a method of forming a yellow image, an image produced
using 256 gradations at the following ratio: R=225, G=225 and B=X
(0.ltoreq.X.ltoreq.225), was used in a color LBP (laser printer)
and a yellow gradation pattern portion presented in the Test Chart
No. 5-1 of Electrophotographic Association was used in a color PPC
(plain paper copier).
[0120] In a method of measuring the surface resistance of each of
image receiving sheets prepared in Examples and Comparative
Examples, a voltage of 500 V was applied to the surface of each
image receiving sheet under a circumstance of 23.degree. C. and 50%
RB and the surface resistance was measured by using a surface
resistance measuring meter (Hiesta, manufactured by Mitsubishi
Petrochemical) at 10 seconds after starting of the
voltage-application.
Parallel-ray Transmittance and Transmittance Density
[0121] A self-made electrophotographic type printer (softening
point of a toner to be used: 100.degree. C., surface temperature of
a fixing roll: 180.degree. C.) was used to make a record in the
image receiving surface of each image receiving sheet obtained in
Examples and Comparative Examples in a manner that a test pattern
of only a yellow image was obtained. The recorded printed product
was measured for the parallel-ray transmittance according to a
method prescribed in JIS K 7105 and for the transmittance density
by using the status A blue filter prescribed in ISO 5-3 and a
transmittance densitometer TR-924 manufactured by Macbeth.
[0122] The results of measurement are shown in Table 1. A graph
obtained by plotting each of measured data is shown in FIG. 6
wherein the abscissa is the transmittance density and the ordinate
is the parallel-ray transmittance.
[0123] As is shown in the table and the graph, it is found from the
results of Examples A-1 to A-3 that the parallel-ray transmittance
of the yellow image portion is 50% or more when the transmittance
density of the yellow image of the electrophotograph is in a range
from 0 to 1.0. Also, it is found from the results of Examples A-1
and A-2 that the parallel-ray transmittance is 55% or more when the
transmittance density of the yellow image is in a range from 0 to
0.6.
[0124] Moreover, in Examples A-1 and A-2, the relationship: Y
.gtoreq.[34/(X +1.2)]+57 is satisfied wherein X represents the
transmittance density and Y represents the parallel-ray
transmittance when the transmittance density of the yellow image is
in a range from 0 to 0.6. The curve shown by the solid line in FIG.
6 shows the relation: Y=[34/(X+1.2)]+57.
7TABLE 1 Example A-1 Example A-2 Example A-3 Comparative Example
A-1 Comparative Example A-2 Trans- Trans- Trans- Trans- Trans-
mittance Parallel-ray mittance Parallel-ray mittance Parallel-ray
mittance Parallel-ray mittance Parallel-ray density transmittance
density transmittance density transmittance density transmittance
density transmittance x y x y x y x y x y 0.04 82.3 0.04 83.3 0.04
83.3 0.04 83.9 0.04 84.7 0.04 80.4 0.07 80.6 0.04 82.8 0.04 82.0
0.04 82.2 0.05 78.1 0.10 78.0 0.05 81.3 0.05 78.0 0.05 77.4 0.06
76.9 0.13 76.4 0.06 79.5 0.06 73.8 0.07 72.7 0.08 74.7 0.17 74.6
0.08 78.0 0.08 67.9 0.10 0.10 72.7 0.21 73.2 0.09 74.7 0.10 61.5
0.12 61.3 0.13 69.4 0.24 73.0 0.12 72.1 0.13 56.4 0.15 57.0 0.14
69.7 0.27 72.3 0.13 70.1 0.14 55.9 0.16 54.1 0.17 69.2 0.31 71.1
0.15 66.8 0.15 52.4 0.19 50.6 0.18 69.2 0.35 69.9 0.17 65.7 0.17
48.2 0.21 47.4 0.22 68.4 0.42 68.1 0.22 61.5 0.21 42.7 0.27 42.9
0.31 64.8 0.48 65.9 0.28 54.2 0.28 39.3 0.36 38.3 0.38 65.3 0.54
64.4 0.34 52.6 0.34 36.0 0.45 37.9 0.43 64.9 0.62 63.6 0.43 54.2
0.38 33.3 0.51 38.0 0.55 64.8 0.65 63.3 0.52 56.1 0.51 34.4 0.63
42.5 0.62 63.0 0.77 61.1 0.63 56.6 0.65 36.6 0.76 44.0 0.73 60.9
0.84 57.9 0.72 53.2 0.71 36.9 0.89 0.80 59.7 0.97 55.2 0.80 52.8
0.77 37.0 0.95 43.9 0.90 57.5 1.09 53.5 0.89 51.8 0.90 38.1 1.10
44.4 0.95 55.3 1.20 0.97 50.0 0.98 39.3 1.14 44.6 1.04 55.1 1.39
41.1 1.03 51.2 1.12 40.6 1.41 45.4
Image Quality
[0125] Using the aforementioned self-made electrophotographic type
printer, a color chart image was formed on each image receiving
sheet by using each toner of yellow, magenta, cyan and black. A
projected image produced when the image receiving sheet was
projected by an OHP was evaluated visually for the occurrence of a
graying phenomenon and tone reproducibility.
[0126] In each of the OHP image receiving sheets formed with an
image in Examples A-1 and A-2, no graying phenomenon is observed
over the whole range from the highlight section to the shadow
section, superior tone reproducibility is attained and a vivid
projected image is obtained. In the OHP image receiving sheet of
Example A-3, a graying phenomenon is observed a little in a middle
density, but almost superior tone reproducibility is attained and
an almost vivid projected image is obtained. On the other hand, in
each of the OHP image receiving sheets of Comparative Examples A-1
and A-2, a graying phenomenon is clearly observed over the whole
range from the highlight section to the shadow section, the tone
reproducibility is inferior and a blurred image is obtained.
Series of Example B
Example B-1
[0127] A receptor layer was formed on one surface of a substrate
film shown below by using a coating solution b1 for a receptor
layer which had the following composition and a resistance control
layer was formed on the receptor layer by using the following
coating solution for a resistance control layer to produce an image
receiving sheet of Example B-1.
[0128] Also, the thickness (dry thickness) of the receptor layer
was set to 2 .mu.m and the thickness of the resistance control
layer was regulated such that the surface resistance of the image
receiving sheet became 1.times.10.sup.10 .OMEGA./.quadrature..
Substrate Film
[0129] Polyethylene terephthalate film with 100 .mu.m in thickness
(100-T60, manufactured by Toray)
Coating Solution b1 for receptor Layer
[0130]
8 Polyester resin (Epicoat 1004, manufactured by Yuka Shell 30
parts Epoxy, number average molecular weight: 1,600, softening
point: 97.degree. C., Tg: 55.degree. C.) Silica filler (average
particle size: 5 .mu.m) 0.5 parts Methyl ethyl ketone 35 parts
Toluene 35 parts
Coating Solution for Resistance Control Layer
[0131]
9 Cation modified quaternary ammonium salt 1 part Isopropyl alcohol
100 parts
Example B-2
[0132] A receptor layer was formed on one surface of the substrate
film used in Example B-1 by using the following coating solution b2
for a receptor layer and a resistance control layer was formed on
the receptor layer by using the coating solution for a resistance
control layer which was used in Example B-1 to produce an image
receiving sheet of Example B-2.
[0133] Also, the thickness (dry thickness) of the receptor layer
was set to 2 .mu.m and the thickness of the resistance control
layer was regulated such that the surface resistance of the image
receiving sheet became 1.times.10.sup.10 .OMEGA./.quadrature..
Coating Solution b2 for Receptor Layer
[0134]
10 Polyester resin (RV220, manufactured by Toyobo, number 30 parts
average molecular weight: 4,000, Tg: 53.degree. C.) Silica filler
(average particle size: 5 .mu.m) 0.5 parts Methyl ethyl ketone 35
parts Toluene 35 parts
Example B-3
[0135] A receptor layer was formed on one surf ace of the substrate
film used in Example B-1 by using the following coating solution b3
for a receptor layer and a resistance control layer was formed on
the receptor layer by using the coating solution for a resistance
control layer which was used in Example B-1 to produce an image
receiving sheet of Example B-3.
[0136] Also, the thickness (dry thickness) of the receptor layer
was set to 2 .mu.m and the thickness of the resistance control
layer was regulated such that the surf ace resistance of the image
receiving sheet became 1.times.10.sup.10 .OMEGA./.quadrature..
Coating Solution b3 for Receptor Layer
[0137]
11 Polyester resin (HP320, manufactured by The Nippon 30 parts
Synthetic Chemical Industry, number average molecular weight:
3,300, Tg: 63.degree. C.) Silica filler (average particle size: 5
.mu.m) 0.5 parts Methyl ethyl ketone 35 parts Toluene 35 parts
Comparative Example B-1
[0138] A receptor layer was formed on one surface of the substrate
film used in Example B-1 by using the following coating solution b4
for a receptor layer and a resistance control layer was formed on
the receptor layer by using the coating solution for a resistance
control layer which was used in Example B-1 to produce an image
receiving sheet of Comparative Example B-1.
[0139] Also, the thickness (dry thickness) of the receptor layer
was set to 2 .mu.m and the thickness of the resistance control
layer was regulated such that the surface resistance of the image
receiving sheet became 1.times.10.sup.10 .OMEGA./.quadrature..
Coating Solution b4 for Receptor Layer
[0140]
12 Polyester resin (HP313, manufactured by the Nippon 30 parts
Synthetic Chemical Industry, number average molecular weight:
8,000, Tg: 64.degree. C.) Silica filler (average particle size: 5
.mu.m) 0.5 parts Methyl ethyl ketone 35 parts Toluene 35 parts
Comparative Example B-2
[0141] A receptor layer was formed on one surface of the substrate
film used in Example B-1 by using the following coating solution b5
for a receptor layer and a resistance control layer was formed on
the receptor layer by using the coating solution for a resistance
control layer which was used in Example B-1 to produce an image
receiving sheet of Comparative Example B-2.
[0142] Also, the thickness (dry thickness) of the receptor layer
was set to 2 .mu.m and the thickness of the resistance control
layer was regulated such that the surface resistance of the image
receiving sheet became 1.times.10.sup.10 .OMEGA./.quadrature..
Coating Solution b5 for Receptor Layer
[0143]
13 Polyester resin (RV200, manufactured by Toyobo, number 30 parts
average molecular weight: 17,000, sofetning point: 163.degree. C.,
Tg: 53.degree. C.) Silica filler (average particle size: 5 .mu.m)
0.5 parts Methyl ethyl ketone 35 parts Toluene 35 parts
[0144] Using the image receiving sheets prepared in the above
Examples and Comparative Examples, the haze value and transmittance
density of a yellow image formed by electrophotography were
measured using the following method and also the image quality was
evaluated.
[0145] In a method of measuring the surface resistance of each of
image receiving sheets prepared in Examples and Comparative
Examples, a voltage of 500 V was applied to the surface of each
image receiving sheet under a circumstance of 23.degree. C. and 50%
RH and the surface resistance was measured by using a surface
resistance measuring meter (Hiesta, manufactured by Mitsubishi
Petrochemical) at 10 seconds after starting of the
voltage-application.
Haze Value and Transmittance Density
[0146] Using a self-made electrophotographic type printer
(softening point of a toner to be used: 100.degree. C., surface
temperature of a fixing roll: 180.degree. C.), only a yellow image
formed in the following condition was recorded in the image
receiving surface of each image receiving sheet obtained in
Examples and Comparative Examples. The recorded printed product was
measured for the haze value according to a method prescribed in JIS
K 7105 by using a Haze meter manufactured by Nippon Denshoku Kogyo
and for the transmittance density by using the status A blue filter
prescribed in ISO 5-3 and a transmittance densitometer TR-924
manufactured by Macbeth.
[0147] Condition of a yellow image: an image produced either in the
same condition as the yellow gradation pattern prescribed in the
Test Chart No. 5-1 of Electrophotographic Association or using data
obtained in the following conditions: 256 gradations, R=225, G=225
and B=X (0.ltoreq.X.ltoreq.225), was used.
[0148] The results of measurement for the above haze value and
transmittance density are shown in Table 2. A graph obtained by
plotting each of measured data is shown in FIG. 7 wherein the
abscissa is the transmittance density and the ordinate is the haze
value.
[0149] As is shown in the table and the graph, it is found from the
results of Examples B-1 to B-3 that the haze value is 40% or less
when the transmittance density of the yellow image of the
electrophotograph is in a range from 0 to 1.0. Also, it is found
from the results of Examples B-1 and B-2 that the haze value is 30%
or less when the transmittance density of the yellow image is in a
range from 0 to 0.6.
[0150] Moreover, in Examples B-1 and B-2, the relationship: Z
.ltoreq.32-17/(7X+0.6) is satisfied wherein X represents the
transmittance density and Z represents the haze value when the
transmittance density of the yellow image is in a range from 0 to
0.6. The curve shown by the solid line in FIG. 7 shows the
relation: Z=32-17/(7X+0.6).
14TABLE 2 Example B-1 Example B-2 Example B-3 Comparative Example
B-1 Comparative Example B-2 Trans- Trans- Trans- Trans- Trans-
mittance Haze mittance Haze mittance Haze mittance Haze mittance
Haze density (haze value) density (haze value) density (haze value)
density (haze value) density (haze value) x z x z x z x z x y 0.04
6.3 0.04 3.5 0.04 5.5 0.04 5.5 0.04 4.7 0.04 7.4 0.07 6.4 0.04 5.6
0.04 7.2 0.04 7.2 0.05 9.3 0.10 8.6 0.05 6.6 0.05 11.7 0.05 12.8
0.06 10.6 0.13 9.9 0.06 8.0 0.06 16.4 0.07 17.5 0.08 12.8 0.17 11.6
0.08 10.0 0.08 23.3 0.10 0.10 14.1 0.21 12.9 0.09 12.9 0.10 30.2
0.12 30.5 0.13 15.4 0.24 13.3 0.12 15.2 0.13 36.1 0.15 35.3 0.14
16.8 0.27 13.8 0.13 17.1 0.14 36.9 0.16 37.8 0.17 17.7 0.31 14.8
0.15 21.3 0.15 41.5 0.19 42.5 0.18 17.2 0.35 16.1 0.17 21.9 0.17
46.3 0.21 45.7 0.22 17.6 0.42 18.5 0.22 26.1 0.21 52.1 0.27 51.2
0.31 20.4 0.48 20.7 0.28 34.3 0.28 54.9 0.36 54.2 0.38 20.5 0.54
22.5 0.34 36.6 0.34 59 0.45 55.9 0.43 19.9 0.62 22.9 0.43 33.9 0.38
61.5 0.51 54.0 0.55 19.5 0.65 24.0 0.52 30.6 0.51 59.7 0.63 48.2
0.62 20.7 0.77 26.2 0.63 29.3 0.65 55.1 0.76 44.3 0.73 23.5 0.84
30.0 0.72 33.2 0.71 55.3 0.89 0.80 24.1 0.97 33.0 0.80 33.0 0.77
54.3 0.95 43.5 0.90 26.6 1.09 35.3 0.89 33.9 0.90 52.5 1.10 42.9
0.95 28.0 1.20 0.97 34.9 0.98 49.7 1.14 41.7 1.04 29.0 1.39 41.1
1.03 33.9 1.12 47.9 1.41 40.0
Image Quality
[0151] Using the aforementioned self-made electrophotographic type
printer, a color chart image was formed on each image receiving
sheet by using each toner of yellow, magenta, cyan and black. A
projected image produced when the image receiving sheet was
projected by an OHP was evaluated visually for the occurrence of a
graying phenomenon and tone reproducibility.
[0152] In each of the OHP image receiving sheets formed with an
image in Examples B-1 and B-2, no graying phenomenon is observed
over the whole range from the highlight section to the shadow
section, superior tone reproducibility is attained and a vivid
projected image is obtained. In the OHP image receiving sheets of
Example B-3, a graying phenomenon is observed a little in a middle
density, but almost superior tone reproducibility is attained and
an almost vivid projected image is obtained. On the other hand, in
each of the OHP image receiving sheets of Comparative Examples B-1
and B-2, a graying phenomenon is clearly observed over the whole
range from the highlight section to the shadow section, the tone
reproducibility is inferior and a blurred image is obtained.
* * * * *