Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Identified backing or protective layer containing
Reexamination Certificate
1998-07-29
2001-05-22
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Identified backing or protective layer containing
C430S531000, C430S935000, C430S939000, C428S046000, C428S220000, C428S339000, C428S910000
Reexamination Certificate
active
06235458
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates of a photographic film and a heat-treatment method thereof.
BACKGROUND OF THE INVENTION
Hitherto, for a photographic light-sensitive material, a wet development is applied using a developer after photographing. However, in the method, there are following inconveniences and the improvement has been desired.
(1) Because a development, bleaching, fixing, and drying are carried out, a long time is required for the photographic treatment.
(2) Because plural tanks containing a developer are required, a processor cannot be small-sized and lightened.
(3) Troubles such as the replenishment of a developer, the disposal of processing liquids, washing of developing tanks, etc., are required,
For the improvement thereof, photographic light-sensitive materials using a development method by heating (hereinafter, sometimes referred to as “heat development”) to a temperature of from 80 to 150° C. are proposed as described in U.S. Pat. No. 3,152,904, U.S. Pat. No. 3,457,075, JP-B-43-4921 (the term “JP-B” as used herein means an “examined Japanese patent publication), JP-B-43-4924, etc. As one example, there is a method of previously incorporating a precursor for a developing agent in a light-sensitive layer, decomposing the precursor by heating to form a developing agent, and developing. In such a heat developing system, the development treatment may be carried out by only application of heat, whereby the treatment can be carried out in a short time and a processor can be small-sized. Furthermore, there are no troubles of the replenishment and the disposal of a developer.
However, in case where the light-sensitive material of this system was applied to a printing light-sensitive material, when 4 plates (blue, green, red, and black plates) were piled up, color discrepancies occurred by the dimensional change occurring during the heat development. To solve the problem, a method of heat treating under a low tension is known as described, for example, in JP-A-60-22616 (The term “JP-A” as used herein means an “unexamined Japanese patent application”), JP-A-64-64883, JP-A-54-158470, and U.S. Pat. No. 2,779,684. By conducting the low-tension heat treatment, the dimensional change between before and after the heat development could be reduced, but accompanied by the heat treatment, inferior planar property (longitudinal wrinkle fault: wrinkles occurring in the longitudinal direction (i.e., the machine direction (MD)) with a pitch of from 10 to 20 cm) occurred. This is a large problem for a photographic support which is required to have a high planar property and as the counterplan thereof, a method of passing a light-sensitive material between rolls is known as described in U.S. Pat. No. 3,663,683. However, in the method, stains occurred on the surface of the photographic support, which was also a large problem. Furthermore, in the cooling process after the heat treatment, an inferior planar property (streaking trouble: galvanized iron sheet-like fine streaks occurring in the longitudinal direction (i.e., the machine direction (MD)) at a pitch of from 1 to 3 cm) occurred.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a photographic film having less surface stains after heat treatment and a good planar property, and also to provide a heat treatment method thereof.
Other objects and effects of the present invention will become apparent from the following description.
The above-described objectives have been achieved by providing the following constitutions.
(1) A method for heat-treating a photographic film while conveying, which comprises the steps of:
passing said photographic film through from 2 to 100 rolls disposed so that gaps between the adjacent rolls are within the range of from 0.1 cm to 50 cm; and
heat-treating said photographic film during the conveyance,
wherein said photographic film comprises a support having coated thereon at least one layer.
(2) The heat-treatment method according to the above (1), wherein the total thickness of the layer(s) coated on said support is from 0.1 &mgr;m to 20 &mgr;m.
(3) The heat-treatment method according to the above (1) or (2), wherein the layer(s) coated on said support are formed from aqueous solution(s).
(4) The heat-treatment method according to any one of the above (1) to (3), wherein said film is conveyed at a tension of from 1 kg/cm
2
to 10 kg/cm
2
.
(5) The heat-treatment method according to any one of the above (1) to (4), wherein said heat-treatment is carried out at from 100° C. to 220° C. for from 0.1 second to 30 minutes.
(6) The heat-treatment method according to any one of the above (1) to (5), wherein said film comprises a polyester.
(7) A method for heat-treating a photographic film, which comprises the steps of:
heat-treating a photographic film; and
winding said heat-treated film, wherein said heat-treated film is cooled before said winding, the cooling rate in the temperature range from the glass transition temperature (Tg) of said film +40° C. to the Tg −10° C. being at 0.01° C./second to 10° C./second.
(8) The heat-treatment method according to any one of the above (1) to (6), which further comprises winding said heat-treated film, wherein said heat-treated film is cooled before said winding, the cooling rate in the temperature range from the glass transition temperature (Tg) of said film +40° C. to the Tg −10° C. being at 0.01° C./second to 10° C./second.
(9) A photographic film having a width direction and a lengthwise direction, and having a thickness unevenness along said film's width direction is from 2 &mgr;m to 300 &mgr;m.
(10) The photographic film of the above (9), wherein the film is prepared by a heat-treatment method according to any one the above (1) to (8).
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the absolute value of heat dimension changing ratio of a support caused by heat treatment at 120° C. for 30 seconds is preferably from 0.001% to 0.04%, more preferably from 0.002% to 0.03%, and further preferably from 0.003% to 0.02%. This requirement regarding the heat dimension changing ratio is preferably satisfied in both the lengthwise direction (i.e., machine direction (MD)) and width direction (i.e., transverse direction (TD)).
The present inventors unexpectedly found that the tension at the heat treatment of a support and preferably also at coating a subbing layer and a back layer becomes an important factor for the heat dimensional changing ratio.
In the case of coating a subbing layer and a back layer, the coated layers are sometimes dried at a high temperature of from 100 to 200° C. and in this step, the support is stretched by a tension and becomes again to have a large residual stress. In this specification, the term “after subbing” means the whole step after forming at least a subbing layer on one surface and a back layer on the other surface of a support.
The tension at the heat treatment, and preferably also at coating a subbing layer and a back layer is from 0.04 kg/cm
2
to 8 kg/cm
2
, preferably from 0.2 kg/cm
2
to 6 kg/cm
2
, and more preferably from 1 kg/cm
2
to 5 kg/cm
2
.
In addition, the tension in the present invention is shown by the value obtained by dividing the force applied to a support by the cross section area (width x thickness) of the support.
The control of such a tension can be easily attained by controlling the torque of a winding motor and/or a delivery motor. Also, the control of the tension can be easily attained by disposing a dancer roller device and controlling a load applied thereto. Furthermore, to control a low tension, a method of previously measuring the heat shrinking amount of the support and reducing the winding amount corresponding to the amount is also preferred.
By the above-described method, the tension generated by a heat shrinking stress is also controlled and the treatment at a more weak tension becomes possible. Also, it is preferred that the width direction is not regulated by clips, etc., but a support is caused to freely shrink. To t
Birch Stewart Kolasch & Birch, LLP.
Chea Thorl
Fuji Photo Film Co. , Ltd.
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