Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Identified backing or protective layer containing
Reexamination Certificate
2000-05-10
2001-07-03
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Identified backing or protective layer containing
C430S533000, C430S536000, C430S538000
Reexamination Certificate
active
06255043
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to imaging materials. It particularly relates to a photographic paper provided with machine readable indicia on the back of the photographic paper.
BACKGROUND OF THE INVENTION
In the formation of color paper it is known that the base paper has applied thereto a layer of polymer, typically polyethylene. This layer serves to provide waterproofing to the paper, as well as providing a smooth surface on which the photosensitive layers are formed. The formation of a suitably smooth surface is difficult requiring great care and expense to ensure proper laydown and cooling of the polyethylene layers. One defect in prior formation techniques is caused when an air bubble is trapped between the forming roller and the polyethylene which will form the surface for casting of photosensitive materials. This air bubble will form a pit that will cause a defect in the photographic performance of photographic materials formed on the polyethylene. It would be desirable if a more reliable and improved surface could be formed at less expense.
In color papers there is a need for providing color papers with improved resistance to curl. Present color papers will curl during development and storage. Such curl is thought to be caused by the different properties of the layers of the color paper as it is subjected to the developing and drying processes. Humidity changes during storage of color photographs lead to curling. There are particular problems with color papers when they are subjected to extended high humidity storage such as at greater than 50% relative humidity. Extremely low humidity of less than 20% relative humidity also will cause photographic papers to curl.
In photographic papers the polyethylene layer also serves as a carrier layer for titanium dioxide and other whitener materials as well as tint materials. It would be desirable if the colorant materials rather than being dispersed throughout the polyethylene layer could be concentrated nearer the surface of the layer where they would be more effective photographically.
It has been proposed in U.S. Pat. No. 5,244,861 to utilize biaxially oriented polypropylene in receiver sheets for thermal dye transfer.
A photographic paper commercially available has a single color printed logo or other brand information printed on the base paper that forms the back of the photographic element. This logo is covered by a layer of polyethylene. The present product is practically limited to a single ink because the present production machines are limited by cost and space limitations to a single color press for printing the indicia onto the back of the base paper.
Other imaging materials also have substrates that are not easily provided with multiple ink printing on the back of the substrate. This includes materials such as thermal dye transfer materials, electrophotographic, and ink jet substrate materials.
During the manufacturing of photographic paper numerous operations require linear measurement of continuous webs for the purposes of minimizing production waste and providing proper customer size product. The current method of measurement is generally a contact method which may be subject to inaccuracy caused by nonuniformity in web conveyance and web surface friction. Physical damage to the web material can also occur through the use of contact measurement devices. Assignment of defective locations within a web is provided using linear measurements. These measurements provide an approximate location for a manual inspection in a separate operation. Large rolls of photographic paper are slit in accordance with customer orders using equipment requiring time consuming operator set up. Locations identified as containing imperfections are removed during the slitting operation.
During the usage of photographic paper, there are several operations which require measurement and alignment of both web and sheet materials. In the printing of web material, it is common for the exposing equipment to create an indexing punch hole between each exposure and also between customer orders. These punch holes are later removed in a chopping operation after photoprocessing has occurred. To advance the web material the proper distance for each exposure a variety of metering rollers and stepper motors are used in conjunction with sensors that detect the punch holes. It is not uncommon for difficulties to arise during the handling and indexing of web materials, such as missed punch holes.
PROBLEM TO BE SOLVED BY THE INVENTION
There is a need for a reliable, low cost, and high quality method of measuring the displacement and cross web locations of web materials, particularly color photographic paper. There is a further need to provide a cleaner environment for imaging equipment, particularly photographic printers in order to reduce the generation of paper dust and other related dirt resulting from the index hole punching operations currently in use. The application of invisible indicia in current manufacturing processes is limited by drying capacity and dimensional change due to the rewetting of the base paper during the application of indicia, therefore restricting the amount of ink that can be applied.
SUMMARY OF THE INVENTION
An object of the invention is to provide a photographic element comprising a paper base, at least one photosensitive silver halide layer, and a layer of biaxially oriented polymer sheet adhered to the backside of the said paper base opposite to the side where said at least one said silver halide photosensitive layer is located, wherein said polymer sheet is provided with invisible indicia on the surface of said sheet between said base paper and said polymer sheet.
ADVANTAGEOUS EFFECT OF THE INVENTION
The invention provides a photographic paper that has a machine readable invisible indicia on the back of the paper. This indicia is provided at low cost and may be applied at high speed to provide a means for more accurate measurement. Such indicia may be used to provide information to slitting and chopping equipment during the manufacturing process.
DETAILED DESCRIPTION OF THE INVENTION
The invention has numerous advantages over prior practice in the art. Currently backside indicia is provided by applying said indicia directly to the base paper prior to the extrusion coating of a melt polymer. The providing of machine readable indicia to the back of photographic paper allows for planar metrology of web and sheet material without contact. “Planar metrology” as used in this application, is defined as point to point measurement of length through the use of predetermined coordinate systems. In a preferred case, rectangular coordinates are used for linear metrology. “Linear Metrology” as used in this application is defined to be the straight line measurement between two points. In web or sheet material applications, both machine and cross machine direction measurements are typically employed. Of particular interest are machine direction measurements. The use of invisible indicia can be applied to linear metrology of high speed webs without surface contact. Said indicia can also be analyzed against time to evaluate and control web speed and linear movement. It further provides the accurate mapping of potentially defective areas of a web, and allows for the precise and rapid locating of such areas for removal. The use of different non-uniformly spaced patterns of indicia can be used to encode a variety of measurements in either the cross web or machine direction. The spacing of indicia must match the capabilities of the equipment that applies and senses the indicia. A practicle range of spacing for either uniform or non-uniform spacing is from 1 mm to 1 m. A preferred range for this invention is from 1 mm to 1 cm. This invention provides the indexing required during photofinishing printing operations and eliminates the need for indexing punch holes.
The application of the invisible indicia on the additional backside sheet also eliminates the need to dry the print on the base paper as the indicia is carried by an additio
Aylward Peter T.
Bourdelais Robert P.
Gula Thaddeus S.
Haydock Douglas N.
Baxter Janet
Eastman Kodak Company
Leipold Paul A.
Walke Amanda C.
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