Stock material or miscellaneous articles – Ink jet stock for printing – Cloth or textile support
Reexamination Certificate
2002-02-12
2003-12-09
Hess, Bruce H. (Department: 1774)
Stock material or miscellaneous articles
Ink jet stock for printing
Cloth or textile support
Reexamination Certificate
active
06660347
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to new stabilizers for recording sheets used in ink jet printing, containing nanoporous inorganic oxides or oxides/hydroxides.
BACKGROUND OF THE INVENTION
Ink jet printing processes are mainly of two types: continuous stream and drop-on-demand.
In continuous stream ink jet printing systems, a continuous ink stream is emitted under pressure through a nozzle. The stream breaks up into droplets at a certain distance from the nozzle. If a specific location on the recording sheet has to be printed the individual droplets are directed to the recording sheet, otherwise they are directed to a gutter. This is done for example by charging unnecessary droplets in accordance with digital data signals and passing them through an electric static field which adjusts the trajectory of these droplets in order to direct them to the gutter. The inverse procedure may also be used wherein uncharged droplets are directed to the gutter.
In the non-continuous process, or the so-called “drop-on-demand” systems, a droplet is generated in accordance with digital data signals only if it is to be placed onto the recording sheet.
The printing speed of modern ink jet printers is always increasing for economical reasons. Recording sheets that are suitable for these printers therefore need to absorb the inks very quickly. Especially suitable are recording sheets containing nanoporous inorganic oxides.
Such recording sheets available today do not meet all of the required demands. In particular, the light stability and the storage stability of images printed on these recording sheets have to be improved. These images are not particularly stable when they are in contact with ambient air, which normally contains sulfur dioxide and, especially in summer, photochemically generated impurities such as ozone or nitrogen oxides. The images are strongly altered or even destroyed in a short time when they are in contact with ambient air. These phenomena are described for example in Hardcopy Supplies Journal, 6 (7), 35 (2000).
In patent application EP 0,373,573 derivatives of polyhydroxybenzenes are proposed as stabilizers for recording sheets for ink jet printing.
Patent application EP 0,534,634 describes the deposition of salt solutions containing at least a bivalent metal cation onto recording sheets for ink jet printing in order to improve the water fastness of the printed images. The copper salts CuCl
2
, CuBr
2
, Cu(NO
3
)
2
, Cu(ClO
3
)
2
and Cu(C
2
H
3
O
2
)
2
are mentioned explicitly.
Patent application JP 1-301,359 describes the addition of organic sulfonates or organic sulfates in combination with copper or nickel salts of monocarboxylic acids to recording sheets for ink jet printing in order to improve the light stability of the printed images. The copper salts copper formate and copper acetate are mentioned explicitly.
In patent application GB 2,088,777 derivatives of phenols and bisphenols are proposed in order to improve the stability of recording sheets containing nanoporous inorganic oxides or oxides/hydroxides.
In patent application EP 0,685,345 the addition of dithiocarbamates, thiocyanates, thiurams or sterically hindered amines to recording sheets containing nanoporous inorganic oxides or oxides/hydroxides is proposed in order to improve their stability.
Patent application WO 00/37,574 describes the addition of bivalent salts of carboxylic acids with at least 4 carbon atoms of copper, nickel, cobalt or manganese to inks as well as to recording sheets for ink jet printing in order to improve the light stability of the printed images. In the examples of table 4 copper gluconate is added to coating compositions containing pseudo-boehmite particles of size smaller than 500 nm and a styrene-acrylic copolymer. The coating compositions are coated subsequently onto transparent polyethylene terephthalate films. No results relating to the stability of images printed onto such recording sheets are given.
Patent application EP 1,034,940 describes a recording sheet that contains, in an ink-receiving layer, binders, a porous inorganic oxide and water-soluble polyvalent metal ions, among others also copper(II) ions.
All of these proposed additives increase the water fastness and the light stability of recording sheets for ink jet printing containing nanoporous inorganic oxides or oxides/hydroxides. However, they do not or only marginally increase the stability of the recording sheets when these are in contact with contaminated ambient air.
European patent application 00810941.5 describes the addition of unsubstituted or substituted 1,3-cyclohexanedione to recording sheets for ink jet printing containing nanoporous inorganic oxides or oxides/hydroxides in order to increase the stability of printed images when these are in contact with contaminated ambient air.
The additives proposed therein however do not sufficiently increase the stability of recording sheets for ink jet printing containing nanoporous inorganic oxides or oxides/hydroxides when these are in contact with contaminated ambient air.
Stabilizing additives for such recording sheets containing nanoporous inorganic oxides or oxides/hydroxides need to be sufficiently soluble and compatible with the other ingredients of the mainly aqueous coating compositions. They need to be colorless or are allowed to be only slightly colored. Furthermore, these additives need to be stable when the recording sheets or the images printed thereon are stored over long periods of time and they are not allowed to yellow or become inactive. Additionally they need to be non-toxic and inoffensive.
There is therefore a need to improve, in addition to the ink absorption capacity, the image quality, the water fastness, the light stability etc., in particular the storage stability of recording sheets containing nanoporous inorganic oxides or oxides/hydroxides when they are in contact with ambient air containing impurities such as ozone, nitrogen oxides or sulfur dioxide.
SUMMARY OF THE INVENTION
An objective of the invention is to provide recording sheets containing nanoporous inorganic oxides or oxides/hydroxides with improved storage stability when in contact with ambient air, where images recorded thereon can be observed by both reflected and transmitted light, and consist of a support having coated thereon at least one ink-receiving layer.
We have found that the addition of salts of salts of monovalent copper not only increases the light stability of recording sheets for ink jet printing containing nanoporous inorganic oxides or oxides/hydroxides, but surprisingly also the storage stability in contact with contaminated ambient air. Images printed onto such recording sheets according to the invention show considerably less change of colors and/or dye losses when in contact with ambient air containing impurities such as ozone, nitrogen oxides or sulfur dioxide in comparison to images printed onto recording sheets not containing such additives.
The recording sheets for ink jet printing according to the invention contain in the coated layers, besides the nanoporous inorganic oxide or oxide/hydroxide and the salts of monovalent copper one or more binders. The salts of monovalent copper may be incorporated into the ink-receiving layer containing the nanoporous inorganic oxide or oxide/hydroxide, or into an other layer of the recording sheet. CuCl is especially effective.
Advantageously unsubstituted or substituted 1,3-cyclohexanedione is incorporated into the recording sheets in addition to the monovalent copper salts.
DETAILED DESCRIPTION OF THE INVENTION
The invention describes a recording sheet for ink jet printing consisting of a support having coated thereon one or more layers comprising, besides at least one nanoporous inorganic oxide or oxide/hydroxide and binders in an ink-receiving layer, salts of monovalent copper. The nanoporous inorganic oxide or oxide/hydroxide and the salts of monovalent copper may be contained in the same or in different layers.
Copper(I) chloride, copper(I) bromide and copper(I) sulfite monohydrate ar
Hess Bruce H.
Ilford Imaging Switzerland GmbH
Onofrio Law
Onofrio, Esq. Dara L.
Shewareged B.
LandOfFree
Recording sheets for ink jet printing does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Recording sheets for ink jet printing, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Recording sheets for ink jet printing will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3097505