U.S. patent number 3,785,820 [Application Number 05/227,636] was granted by the patent office on 1974-01-15 for photorecording process and photorecording member.
This patent grant is currently assigned to Canon Camera Kabushiki Kaisha. Invention is credited to Ichiro Endo, Eiichi Inoue, Hajime Kobayashi, Isamu Shimizu.
United States Patent |
3,785,820 |
Inoue , et al. |
January 15, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
PHOTORECORDING PROCESS AND PHOTORECORDING MEMBER
Abstract
A photochromic compound, particularly, spiropyran compound, is
used for producing images. The difference of properties such as
polarity and solubility between the colored species and the
colorless species is utilized to produce the images and the
spiropyran compound is maintained in a dense state to obtain a
stable colored state.
Inventors: |
Inoue; Eiichi (Tokyo,
JA), Shimizu; Isamu (Tokyo, JA), Endo;
Ichiro (Tokyo, JA), Kobayashi; Hajime (Tokyo,
JA) |
Assignee: |
Canon Camera Kabushiki Kaisha
(Tokyo, JA)
|
Family
ID: |
22853872 |
Appl.
No.: |
05/227,636 |
Filed: |
February 18, 1972 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
805357 |
Mar 7, 1969 |
|
|
|
|
Current U.S.
Class: |
430/19; 430/336;
430/345; 430/962 |
Current CPC
Class: |
G03C
1/685 (20130101); Y10S 430/163 (20130101) |
Current International
Class: |
G03C
1/685 (20060101); G03c 005/24 () |
Field of
Search: |
;96/48,9PC |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Torchin; Norman G.
Assistant Examiner: Goodrow; John L.
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper &
Scinto
Parent Case Text
This is a Continuation of application Ser. No. 805,357 filed Mar.
7, 1969 now abandoned.
Claims
What we claim is:
1. A photorecording process which comprises applying an imagewise
radiation to a photosensitive layer comprising a spiropyran
compound and a non-polar dispersion medium in an exposure amount
and time duration sufficient to produce (1) an initial colored
image in an unstable monomolecular colored state and thereafter (2)
a stable colored species of low solubility adapted to form a stable
colored image in a coagulated and associated stable colored state,
said stable colored state uneffected by radiation and heat, wherein
said stable colored state has a broader absorption spectrum when
said initial monomolecular colored state.
2. A photorecording process which comprises applying a blanket
irradiation of a radiation to a photosensitive layer comprising a
spiropyran compound and a non-polar dispersion medium in an
exposure amount and time duration sufficient to produce (1) an
initial colored image in an unstable monomolecular colored state
and thereafter (2) a stable colored species of low solubility
adapted to form a stable colored image in a coagulated and
associated stable colored state, said stable colored state
uneffected by radiation and heat, wherein said stable colored state
has a broader absorption spectrum then said initial monomolecular
colored state, next wetting the surface of the colored
photosensitive layer with a polar liquid dispersion medium
toconvert it to a color-erasable colored state, and then applying
an imagewise irradiation by a radiation capable of erasing the
color-erasable colored state to form an image.
3. A method for forming an image which comprises applying an
imagewise irradiation by a radiation to a photosensitive layer
comprising a spiropyran compound and a non-polar dispersion medium
in an exposure amount and time duration sufficient to produce (1)
an initial colored image in an unstable monomolecular colored state
and therafter (2) a stable colored species of low solubility
adapted to form a stable colored image in a coagulated and
associated stable colored state, said stable colored state
uneffected by radiation and heat, wherein said stable colored state
has a broader absorption spectrum then said initial monomolecular
colored state, and then removing the colored species of the
spiropyran compound at the colored portion of the resulting colored
image using a polar solvent.
4. A photorecording process according to claim 1 in which the
non-polar dispersion medium is removed by vaporization after
imagewise exposure.
5. A photorecording process according to claim 1 in which after
producing stable colored images by imagewise exposure, the colored
image surface is wetted with a polar dispersion medium to convert
the stable colored image to a color-erasable colored state.
6. A photorecording process according to claim 5 in which the
color-erasable state is erased by using a radiation, heat or a
mixture thereof.
7. A method for forming an image according to claim 3 in which the
non-colored species of the spiropyran compound at the non-colored
portion of the stable colored image is removed using a non-polar
solvent.
Description
This invention relates to a photorecording process and
photorecording member. More particularly, it relates to an improved
photorecording process utilizing photochromism and a photorecording
member comprising photochromic material.
The term "photochromism" is generally defined as a reversible color
transformation caused when a material is exposed to a radiation.
This color transformation is generally considered to be caused by
isomerization, dissociation, oxidation, reduction or formation of
an excited state etc. When the stimulation by a radiation is
removed, the photochromic material reverts to its original state,
and a reversible color transformation occurs by repeated
stimulations. Efficiency in reverting to the original state of some
materials is increased by the stimulation of radiation having a
wave length different from that of a radiation capable of forming a
colored species. One of the photochromic compounds preferred in
this invention is a spiropyran compound which may be represented by
the following general formula: ##SPC1##
Where R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are as defined
below, and it is considered that this compound is in a colored
state when the C--O bond cleaves and it is in a colorless state
when the C--O bond is closed. In other words, when the intrinsic
absorption region of the spiropyran compound is stimulated by, for
example, ultraviolet ray, it changes to a colored state having a
new absorption at the visible region. This colored state continues
for a certain period of time, but it reverts to the original state
by stimulating the new visible region with light or heat. That is,
this compound shows photoreversible photochromism. This invention
is based on the principle that photochromic materials,
particularly, spiropyran compounds and derivatives thereof, are in
a colored state when the structure is in a cleavage state and in a
form of zwitter ion, and the compounds at such state and form are
of high polarity, of low solubility in a non-polar dispersion
medium and in a dense state, and therefore, the colored state is
stabilized.
According to this invention, the photochromic material is retained
in a dense state at least at the colored state to stabilize the
colored state, and further, the difference of solubilities of the
colored species and the colorless species is utilized to separate
these both species by dissolving and removing either the colored
species or the colorless species. Thus, there is obtained an image
of high resolving power in which the photochromic material is
present only at the colored portion or the colorless portion.
An object of this invention is to provide a photorecording process
producing a stable colored state.
A further object of this invention is to provide a photorecording
process in which the colored state can be reverted to a
color-eliminatable state by a chemical treatment.
A further object of this invention is to provide a photorecording
process which can produce stable images of high contrast.
A further object of this invention is to provide a photorecording
process and a photorecording member which are useful for recording,
storing, accumulation, amendment, elimination and layout of
information in calculation, translation, communication,
documentation and other various information treating mechanism.
A further object of this invention is to provide a photorecording
process which comprises utilizing the remarkable difference of the
polarity between the colored species and the colorless species and
the difference of the solubility in various solvents, dissolving
away either the colored species or the colorless species to produce
images of high resolving power in which either the colored species
or the colorless species is present.
A further object of this invention is to provide a photorecording
member which comprises a dense state of photochromic material of
stable colored state.
A further object of this invention is to provide a photorecording
process in which the resulting colored image is of long life and of
high quality, and if desired, the elimination and the reuse are
possible, and a photorecording member therefor.
A further object of this invention is to provide a photorecording
member which gives red to black colored images having high degree
of light absorption and high density of color and a photorecording
method therefor.
As mentioned above, this invention is based on a principle that
photochromic materials, particularly, spiropyran compounds, are in
a cleavage state at the colored state and are of high polarity and
of low solubility in a non-polar dispersion medium and the colored
species at the cleavage state is in a dense state. And a stable
state of photochromic material is obtained at least at the colored
state. In this invention, a "dense state" in a colored state or in
a colorless state is such a state that the colored species in the
colored state or the colored species converted from the colorless
species in case of the colorless state are coagulated and
associated in the colored state and the absorption spectrum at the
colored state is broader than that of the colored species when the
colored species is present in a monomolecular state.
Preferable radiations used in this invention are .alpha.-ray,
.beta.-ray, .gamma.-ray, X-ray, ultraviolet ray, visible light,
infrared ray etc.
As methods for retaining the photochromic material in the colored
state at a dense state, there are mentioned, for example, a method
which comprises applying uniformly a spiropyran compound to a
self-supporting material, exposing the resulting photochromic layer
to a radiation capable of color-forming to convert to the colored
state, in which an appropriate dispersion medium is selected to
utilize the low solubility of the colored spiropyran in the
dispersion medium during or after the exposure, whereby a dense
state is formed to produce a stable colored state, and a method
which comprises applying a radiation capable of color-forming to a
spiropyran compound existing in a dense state on a self-supporting
material to obtain a stable colored state.
As methods for color-eliminating the colored state in a dense state
formed as mentioned above in the photorecording process of this
invention, there is mentioned, for example, a method which
comprises dissolving the colored species away by using an
appropriate dispersion medium, for example, polar solvent to
convert to a colored species which can be color-eliminated,
color-converting the dissolved colored species which can be
color-eliminated in accordance with the kind of the solvent, and
applying a light of the absorption wave length range corresponding
to that of the colored species or heat to the colored species to
convert it to the colorless state.
In the photorecording process of this invention, images comprising
only colored species or only colorless species may be obtained in
order to have images of high contrast. In this process, there is
utilized the difference in properties such as electrical,
magnetical, chemical and other physical properties, due to the
remarkable difference in the molecular structure between the
colored species and the colorless species of photochromic material,
particularly, spiropyran compound. More particularly, the
remarkable difference of the solubility in solvent due to the
marked difference of the polarity is advantageously utilized. In
other words, it has been now found that the colorless species of
spiropyran compound is in a ring-closure state and has low polarity
so that it is soluble in a non-polar solvent while the polar
colored species is in a form of zwitter ion and has high polarity
so that it is soluble in a polar solvent, but not in a non-polar
solvent.
According to the present invention, the above-mentioned phenomena
are utilized and a spiropyran compound is exposed to a radiation to
color-form followed by treating the spiropyran compound with an
appropriate solvent to dissolve and remove either the colored
species or the colorless species producing the images. The
color-converted colored species can easily revert to the colorless
species by stimulating the colored species with a light having the
absorption wave length range corresponding to that of the colored
species or heat.
According to this invention, the above-mentioned features are
utilized for carrying out the photorecording process more
effectively.
The important components employed in the present invention are as
follows:
A. spiropyran compound
B. dispersion medium
C. solvent
A. preferable spiropyran compounds employed in this invention are
compound represented by the following general formula: ##SPC2##
where R.sub.2, R.sub.3 and R.sub.4 are, similar or dissimilar,
selected from the group consisting of hydrogen, alkyl and aryl; and
R.sub.1 and R.sub.5 are, similar or dissimilar, selected from the
group consisting of nitro, alkoxy, hydroxy, carboxy, halo,
carboalkoxy, alkyl, alkenyl, and aryl; and one or more of R.sub.1
and R.sub.5 may be attached to the respective six-membered ring,
and the naphthopyran derivatives, the thiazole derivatives, and the
oxazole derivatives etc. thereof.
Representative examples of the spiropyran compounds and the related
compounds as mentioned above are:
1,3,3,-trimethyl-6'-nitro-8'-allyl-spiro(2'H-1'-benzopyran-2,2'-indoline),
1,3,3-trimethyl-5,6'-dinitro-spiro(2'H-1'-benzopyran-2,2'-indoline),
1,3,3-trimethyl-7'-nitro-spiro(2'H-1'-benzopyran-2,2'-indoline),
3-methyl-6-nitro-spiro-[2H-1-benzopyran-2,2'-(2'H-1'-.beta.-naphthopyran)],
1,3,3-trimethyl-8'-nitro-spiro(2'H-1'-benzopyran-2,2'-indoline),
1,3,3-trimethyl-6'-methoxy-8'-nitro-spiro(2'H-1'-benzopyran-2,2'-indoline),
1,3,3-trimethylindoline-8'-carboxybenzopyrylspiran,
1,3,3-trimethyl-5-chloro-5'-nitro-8'-methoxy-spiro(2'H-1'-benzopyran-2,2'-i
ndoline),
1,3-dimethyl-3-isopropyl-6'-nitro-spiro(2'H-1'-benzopyran-2,2'-indoline),
1-phenyl-3,3-dimethyl-6'-nitro-8'-methoxy-spiro(2'H-1'-benzopyran-2,2'-indo
line),
7'-nitro-spiro[xantho-10,2'-(2'H-1'-benzo .beta.
naphthopyran)],
3,3'-dimethyl-6'-nitro-spiro(2'H-1'-benzopyran-2,2'-benzothiazole),
3,3'-dimethyl-6'-nitro-spiro(2'H-1'-benzopyran-2,2'-benzothiazole),
3,3'-dimethyl-6'-nitro-spiro(2'H-1'-benzopyran-2,2'-benzo-oxazole),
1,3,3-trimethyl-6'-nitro-spiro(2'H-1'-benzopyran-2,2'-indoline),
6'-nitro-8'-methoxy-1,3,3-trimethylindolinobenzopyrylspiran,
6'-nitro-1,3,3-trimethylindolinobenzopyrylspiran,
8'-allyl-1,3,3-trimethylindolinobenzopyrylspiran,
8'-carboxymethoxy-1,3,3-trimethylindolinobenzopyrylspiran,
8'-methoxy-1,3,3-trimethylindolinobenzopyrylspiran,
6',8'-dinitro-1,3,3-trimethylindolinobenzopyrylspiran,
7'-nitro-1,3,3-trimethylindolinobenzopyrylspiran,
8'-nitro-1,3,3-trimethylindolinobenzopyrylspiran,
6'-8'-dibromo-1,3,3-trimethylindolinobenzopyrylspiran,
6'-chloro-8'-nitro-1,3,3-trimethylindolinobenzopyrylspiran,
5-nitro-6'-nitro-1,3,3-trimethylindolinobensopyrylspiran,
6'-nitro-8'-fluoro-1,3,3-trimethylindolinobenzopyrylspiran,
6'-methoxy-8'-nitro-1,3,3-trimethylindolinobenzopyrylspiran,
5'-nitro-8'-methoxy-1,3,3-trimethylindolinobenzopyrylspiran,
and
6'-bromo-8'-nitro-1,3,3-trimethylindolinobenzopyrylspiran.
B. dispersion medium
1. Liquid matrix
As examples of liquid matrix, the following are mentioned:
pentane, hexane, heptane, cyclohexane, dioxane, cyclchexene, carbon
tetrachloride, decahydronaphthalene, xylene, toluene, benzene,
carbon disulfide, ethylether, chloroform, ethyl acetate, trichlene,
fluid paraffin, water, formaldehyde, furfural, acetonitrile,
methanol, ethanol, acetone, n-propylalcohol, butanol, pyridine
etc.
Furthermore, a mixture of these compounds may be also used.
2. Solid matrix
As examples of solid matrix, there are mentioned the following:
nitrocellulose, cellulose acetate, ethylcellulose, polyethylene,
polystyrene, polyvinyl acetate, polyvinyl chloride,
polyacrylonitrile, vinyl chloride, polymethylmethacrylate, gelatin,
paraffin, and wax, etc;
oligomers known as low polymer having relatively lower degree of
polymerization, and non-polymer organic compounds capable of
forming a mono-molecular layer film and not reactive with the
spiropyran compounds.
It is desirable to select appropriately the solvent for the
above-mentioned polymers and organic compounds.
C. solvent
As examples of solvent, the following are mentioned:
water, formaldehyde, furfural, acetonitrile, methanol, ethanol,
acetone, n-propyl alcohol, butanol, pyridine etc.
A mixture of these compounds may be also employed. Further, such
solvent containing inorganic compound may be effectively used. As
solvents of low polarity, benzene, toluene, xylene, cyclohexane,
n-hexane, dioxane, and pentane are preferred. A mixture of these
solvent also can be used. In the present invention, any solvent
which can selectively dissolve or coagulate the colorless portion
or the colored portion and shows different solubilities to these
both portions may be used effectively.
The process for recording images in this invention is shown
below.
1. Spiropyran compound is uniformly applied to a self-supporting
material such as resin, glass, metal, paper, fiber, wood, ceramics
and the like and then a radiation capable of color-forming such as
ultraviolet ray and the like is applied to the layer containing the
spiropyran compound obtained above to convert to the colored state.
By selecting appropriately the dispersion medium in which the
spiropyran compound is dispersed, the solored species resulting
from applying the radiation to the colored compound coagulates,
during or after the stimulation by the radiation, to a dense state
due to the low solubility of the colored spiropyran compound formed
in the dispersion medium.
2. A spiropyran compound is applied to a self-supporting material
in a dense state and then exposed to a radiation capable of
color-forming to convert the spiropyran compound in a dense state
to a stable colored state. The method for forming a dense state of
the colored species is further explained below. For example, a
spiropyran compound is dissolved and dispersed in an appropriate
dispersion medium and a radiation capable of color-forming is
applied thereto to convert to the colored state. By selecting an
appropriate dispersion medium, the colored species can be formed as
a dense state by utilizing the lowered solubility of the colored
spiropyran during or after the stimulation of the radiation. And
the spiropyran compound is dissolved in a solvent and the resulting
solution is applied to the surface of a self-supporting material
such as resin, glass, metal, paper, fiber, wood, ceramics and the
like and dried. This procedure is repeated to convert the
spiropyran compound to a dense state and then a radiation capable
of color-forming is applied to convert to the colored state. Or a
photochromic material is melted to form a layer in a dense state.
The method for forming a photosensitive layer containing a
photochromic material in a dense state in this invention is not
limited to the above-mentioned methods, but other various methods
may be used.
3. The colored state in a dense state as produced by the
above-mentioned methods 1 and 2 is treated with a polar solvent to
dissolve the colored species converting it to a color-eliminatable
colored species, and when the dissolved color-eliminatable colored
species is exposed to a light having an absorption wave length
range of the colored species or heat, it reverts to the original
colorless state. On the contrary, since the colorless state is in a
state of low polarity, sharp images can be obtained by dissolving
the colorless portions by using a non-polar solvent.
Further, the detailed explanation is given below.
1. A spiropyran compound is dissolved in a non-polar dispersion
medium and the resulting mixture is applied to a self-supporting
material such as resin, glass, metal, paper, fiber, wood, ceramics
and the like to form a recording member. The resulting recording
member is subjected to an image irradiation by a color-forming
light such as ultraviolet ray while the dispersion medium is still
present. Thus, a colored image is obtained by the colored species
of the spiropyran compound. Since this colored species has low
solubility in a non-polar dispersion medium, a coagulated matter of
the colored species is formed and the colored state is retained in
a dense state and is stable.
When the above-mentioned stable state is treated with a polar
dispersion medium, a reversible process, i.e. color-elimination by
light or heat.
2. A spiropyran compound is dissolved or dispersed in a non-polar
high polymer of low dielectric constant. The resulting mixture is
applied to a self-supporting material such as resin, glass, metal,
paper, fiber, wood, ceramics and the like to form a recording
member, or the above-mentioned mixture itself may form a
self-supporting photosensitive matter. When this recording member
is exposed to a color-forming light such as ultraviolet ray, a
colored image is obtained by the formation of colored species of
the spiropyran compound. This colored species becomes a coagulating
state and the colored state is kept in a stable state. The
treatment of the above-mentioned state by a polar dispersion medium
accelerates the reversible process, i.e. the color-elimination by
light or heat.
3. A spiropyran compound is applied to a self-supporting material
such as resin, glass, metal, semiconductor, paper, fiber, wood,
ceramics and the like to form a photosensitive member. A radiation
having sufficient energy to excite the spiropyran compound is
applied to the resulting photosensitive member to convert an
optional portion to the colored state. Or when the whole surface is
first converted to a colored state, or with respect to a
photosensitive member comprising a spiropyran compound already in a
colored state, a radiation capable of color-eliminating is applied
to color-eliminate selectively the optional portions and the images
are produced. And a solvent is applied to the photosensitive member
having the images formed as mentioned above to remove the colored
portions or the colorless portions. The solvent used is that which
can dissolve the portions to be removed. As the dissolving and
removing methods, there are mentioned, for example, soaking the
photosensitive member in an appropriate solvent, spraying the
solvent onto the photosensitive member, and flowing away the
portions to be removed with the solvent. When the colorless
portions are dissolved away by the above-mentioned solvent
treatment, colored images are produced. The above-mentioned colored
state is gradually faded due to the intrinsic property of
photochromic material. The faded colored state may be color-formed
again by applying a radiation capable of color-forming thereto.
Since photochromic material is present only at the image portions
in the photosensitive member treated as above, a whole surface
exposure is sufficient to color-form again, and it is not necessary
to use a radiation of high resolving power. On the other hand, when
the colored species is dissolved away, the pattern composed of
colorless species can be converted to a colored state by applying a
radiation thereto. The conditions in this case are similar to those
in the above-mentioned case where colored portions are retained to
form images and a whole surface exposure is effected.
The following examples are given by way of illustration and not
limitation of this invention.
Example 1
1,3,3-Trimethylindolino-6'-nitrobenzopyrylspiran (50 mg.) was
dissolved in 10cc. of toluene, and the obtained solution was
uniformly applied to an art paper of about 80 .mu. thick, and when
the coating was not yet perfectly dried, image exposure was given
thereto at a distance of 20 cm from the light source for 60 seconds
by using the ultraviolet ray obtained by passing the light from a
500w super high pressure mercury lamp (produced by Ushio Electric
Co., Ltd) through Toshiba Glass Filter UV-D 25 (Trade name). Bluish
purple image was first obtained, and then it was turned into black
image gradually. The black image was not faded by ultraviolet ray
or visible light at all. The black image could be retained stably
for more than 9 months at room temperature. The bluish purple image
had the absorption maximum at about 600 m.mu., and when the image
was turned to black and became a dense state, the absorption
maximum was at 560 m.mu. and the absorption spectrum became broad.
Next, when the black image was subjected to a wetting treatment by
using ethyl alcohol, the black image was turned to reddish
purple.
After the treatment, the same light source and Toshiba Blass Filter
UV-39 (Trade name) was employed to remove the wave length shorter
than 390m.mu., and the irradiation of visible light was carried out
at a distance of 20 cm. from the light source for 30 seconds, and
the reddish purple image was erased.
Example 2
1,3,3-Trimethylindolino-6'-nitrobenzopyrylspiran 70 mg.
Polystyrene 1.5 gr.
The above given ingredients were dissolved in 10 cc. of xylene, and
the obtained solution was applied to a photographic ferro plate,
and the resulting coating was dried to give a transparent film.
Thus obtained film was subject to ultraviolet ray irradiation by
using a combination of Toshiba Glass Filter UV-D-25 and a 250 w
super high pressure mercury lamp at the distance of 10 cm. from the
light source for one minute, and it was turned into bluish black.
No change was observed in this state even if further ultraviolet
ray irradiation or the irradiation of visible light was carried
out.
Thereafter the surface of the photosensitive matter was subjected
to a wetting treatment by using acetonitrile and then to the
visible light irradiation at a distance of 50 cm. for 1 minute by
using a 250 w tungsten lamp, and the image was perfectly
erased.
Example 3
1,3,3-Trimethylindolino-6'-nitrobenzopyrylspiran 100 mg.
Paraffin 2 gr.
The above given ingredients were dissolved in 10 cc. of
cyclohexane, and the resulting solution was applied to a two-sided
art paper of 100 .mu. thick to prepare a photosensitive matter.
The resulting photosensitive matter was subjected to irradiation at
a distance of 15 cm. from the light source for 1 minute by using
Toshiba 100 w ultra high pressure mercury lamp, and thus the
exposed portion was turned into black. The black product was not
affected by ultraviolet ray or visible light. The black product
could be retained stably at room temperature for more than 5
months.
Next, when the black state was subjected to a wetting treatment by
using acetone, it was changed from black to reddish purple. After
the treatment, the irradiation of visible light was carried out in
the same manner as in Examples 1 and 2, and the reddish purple
image was eliminated.
Thereafter, when the acetone was perfectly evaporated, the
photosensitive matter reverted to the original state, i.e. it can
be changed to a black state again by irradiation of ultraviolet
ray.
Example 4
1,3,3-Trimethylindolino-6'-nitro-8'-methoxybenzopyrylspiran 100
mg.
Paraffin 1 gr.
The above given ingredients were dissolved in 10 cc. of trichlene,
and the obtained solution was uniformly applied to an art paper of
about 80 .mu. thick and dried to form a photosensitive matter.
Before the above prepared photosensitive matter was exposed to
light, a wetting treatment was carried out by using cyclohexane,
and then ultraviolet ray obtained by using a 250 w super high
pressure mercury lamp and Toshiba Glass Filter UV-D 25 was
irradiated at a distance of 10 cm. from the light source for 1
minute, and bluish green color appeared, and then it gradually
turned into black.
The black state was not affected by ultraviolet ray or visible
light.
Thereafter, weting treatment was carried out by using methanol, and
black state was turned into reddish purple.
After the treatment, color developed state was eliminated by
irradiating visible light in the same manner as in Example 1.
The absorption maximum in bluish green state was at about 620
m.mu., and as the light irradiation proceeded, the state changed to
a black state having a broad absorption ranging from 500 m.mu. to
600 m.mu.. This black state was not faded by ultraviolet ray and
visible ray. Then, the wetting treatment with methanol changed the
black state to a reddish purple. After this treatment, it was
subjected to irradiation of visible ray in a similar way to Example
1 above and the colored state was eliminated.
Example 5
1,3,3-Trimethylindolino-6'-nitro-8'-methoxybenzopyrylspiran (50
mg.) was dissolved in 10 ml. of benzene and a part of the resulting
solution was spread over a glass plate (20 cm. .times. 30 cm.) hold
horizontally. The solvent in the spread solution was vaporized and
the spreading was repeated five times in total to form a
photochromic photosensitive layer. The resulting photosensitive
layer was exposed to the ultraviolet ray obtained by passing a
light from a 1 Kw super high pressure mercury lamp (manufactured by
Ushio Electric Co., Ltd.) through a Toshiba Glass Filter UV-D25 at
a distance of 15 cm. for 3 minutes. The exposed portion was changed
to blue.
Then the following dissolving procedure was carried out.
1. The above photosensitive matter having images formed by the
presence of the colored state and the colorless state was soaked in
cyclohexane for 30 minutes to dissolve the colorless part away and
retain the colored part. The above-mentioned colored part was
color-eliminated with the passage of time, but when irradiation of
ultraviolet ray was applied to the whole surface, it was colored as
previously.
2. The photosensitive matter having images as in 1 above was
subjected to a treatment of spraying methanol for 1 minute to
dissolve the colored portion, and consequently only the colorless
portion remained. After this treating, the whole surface of the
photosensitive matter was exposed to an ultraviolet ray to be
colored, and thus a normal image corresponding to the negative used
as the pattern was obtained.
Example 6
A photosensitive layer was formed in the same way as in Example 5
by using 1,3,3-trimethylindolino-5-chloro-6'-nitrobenzopyrylsipiran
and was colored by a whole surface irradiation of ultraviolet ray.
The resulting photosensitive layer was exposed through a negative
to a visible light obtained by using a 500 w tungsten lamp and
Toshiba Glass Filter VY-43 (Trade name) at a distance of 30 cm. for
1 minute. Thus, the exposed portion was color-eliminated and
reverted to the colorless state. Then, a dissolving procedure as in
Example 5 was effected, n-Hexane was used for dissolving the
colorless portion while ethanol was used for dissolving the colored
portion, and similar results was obtained.
Example 7
1,3,3-Trimethylindolino-8'-carboxybenzopyrylspiran (40 mg.) was
dissolved in 10 ml. of ethanol and spread over a glass plate 6
times as in Example 5 to form a photosensitive layer. This compound
is originally red before exposed to a light and the red color is
eliminated. This phenomenon is a reverse photochromism. The visible
light source as used in Example 2 was used to apply an image-wise
irradiation to the above-mentioned photosensitive matter. The
exposed portion was color-eliminated to form images
(positive-positive). The images were subjected to the treatment as
described in Examples 1 and 2 to dissolve selectively the colored
portion and the colorless portion.
* * * * *