Record receiver having plural interactive leaves or a colorless – Having a colorless color-former – developer therefor – or... – Method of use – kit – or combined with marking instrument or...
Reexamination Certificate
2002-03-26
2004-08-10
Hess, Bruce (Department: 1774)
Record receiver having plural interactive leaves or a colorless
Having a colorless color-former, developer therefor, or...
Method of use, kit, or combined with marking instrument or...
C503S212000
Reexamination Certificate
active
06774084
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to thermographic recording materials whose prints have improved thermal development efficiency.
BACKGROUND OF THE INVENTION
Thermal imaging or thermography is a recording process wherein images are generated by the use of thermal energy. In direct thermal thermography a visible image pattern is formed by image-wise heating of a recording material.
EP-A 903 625 discloses a substantially light-insensitive black and white monosheet thermographic recording material is provided comprising a support and a thermosensitive element containing a substantially light-insensitive organic silver salt, a 1,2-dihydroxyphenyl-compound in thermal working relationship therewith and a binder, characterized in that the 1,2-dihydroxyphenyl-compound is represented by formula (I):
where R is —P(═O)R
1
R
2
, —SO
x
R
3
, —CN, —NO
2
or —CR
4
═NR
5
when n is 0; R is —P(═O)R
1
R
2
, —SO
x
R
3
, —CN, —NO
2
, —CR
4
═NR
5
or —COR
6
when n is a integer; R
1
and R
2
are independently an alkyl, a substituted alkyl, an aryl, a substituted aryl group, an alkoxy, a substituted alkoxy, an aryloxy, a substituted aryloxy, a hydroxy group, an amino group or a substituted amino group; R
3
is an alkyl, a substituted alkyl, an aryl, a substituted aryl, an amino or a substituted amino group; R
4
is an alkyl, a substituted alkyl, an aryl or a substituted aryl group or hydrogen; R
5
is an alkyl, a substituted alkyl, an aryl, a substituted aryl, a hydroxy, an alkoxy, an aryloxy, an acyl, an amino or a substituted amino group; R
6
is an alkyl, a substituted alkyl, an aryl, a substituted aryl, an alkoxy, a substituted alkoxy, an aryloxy, a substituted aryloxy, a hydroxy, an amino or a substituted amino group or hydrogen; x is 1, 2 or 3; and the benzene ring of the 1,2-dihydroxyphenyl-compound represented by the formula (I) may be further substituted.
EP-A 978 760 discloses a substantially light-insensitive black and white monosheet thermographic recording material comprising a support and a thermosensitive element containing a substantially light-insensitive organic silver salt, a 1,2-dihydroxyphenyl-compound in thermal working relationship therewith and a binder, characterized in that the 1,2-dihydroxyphenyl-compound is represented by formula (I):
where n is 0 or 1; R is —(C═O)R
1
, —(C═O)NR
1
R
2
, —CN, —SO
3
R
2
, —SO
2
R
2
, —SOR
2
, —SO
2
NR
2
R
3
or —PO
3
R
2
R
3
; R
1
is H or a substituted or unsubstituted alkyl group with 12 or less carbon atoms; and R
2
and R
3
are independently H or an alkyl, a substituted alkyl, an aryl or a substituted aryl group; and R
1
and R
2
together can provide the atoms to close a carbocyclic or heterocyclic ring; and R
2
and R
3
together can represent the atoms to close a carbocyclic or heterocyclic ring
Prior art thermographic recording materials whose prints exhibit acceptable archivability exhibit unsatisfactory D
max
/(silver behenate) coverage ratios i.e. the quantity of silver behenate required to obtain a given D
max
is too high. A means is needed to increase the D
max
/(silver behenate) coverage ratio without deterioration in print archivability.
ASPECTS OF THE INVENTION
It is therefore an aspect of the present invention to provide improved reducing agents for substantially light-insensitive black and white thermographic recording materials with improved thermal development efficiency i.e. improved D
max
/(organic silver salt coverage) ratios without significant deterioration in archivability of the prints obtained therewith.
Further aspects and advantages of the invention will become apparent from the description hereinafter.
SUMMARY OF THE INVENTION
Surprisingly it has been found that particular types of novel reducing agents produce an improvement in thermal development efficiency in thermographic recording materials as shown by an increase in the D
max
/(organic silver salt coverage) ratio without significant deterioration in archivability of the prints thereby obtained.
The above mentioned aspects are realized by providing a monosheet black and white substantially light-insensitive thermographic recording material comprising a thermosensitive element and a support, the thermosensitive element containing a substantially light-insensitive organic silver salt, a 1,2-dihydroxyphenyl-compound in thermal working relationship therewith is and a binder, wherein said 1,2-dihydroxyphenyl-compound is represented by formula (I): R
1
SO
2
R
2
, wherein R
1
is an optionally substituted aryl group and R
2
is selected from the group consisting of a 3,4,5-trihydroxyphenyl group, a 3-alkoxy-4,5-dihydroxyphenyl group and a 3-aryloxy-4,5-dihydroxyphenyl group; or said 1,2-dihydroxyphenyl-compound is represented by formula (II): R
3
COOR
4
, wherein R
3
is a 3-alkoxy-4,5-dihydroxyphenyl group or a 3-aryloxy-4,5-dihydroxyphenyl group; and R is an alkyl group or an aryl group. Combinations of compounds according formula (I) or formula (II) may also be used that on heating become reactive partners in the reduction of the substantially light-insensitive organic silver salt.
The above mentioned aspects are also realized by providing a thermographic recording process for a monosheet black and white substantially light-insensitive thermographic recording material according to any of the preceding descriptions comprising the steps of: (i) providing the thermographic recording material; (ii) bringing the thermographic recording material into the proximity of a heat source; (iii) applying heat imagewise from the heat source to the thermographic recording material; and (iv) removing the thermographic recording material from the proximity of the heat source.
Several embodiments are disclosed in the description set forth herein.
REFERENCES:
patent: 5672560 (1997-09-01), Rush
patent: 0 903 625 (1999-03-01), None
patent: 0 978 760 (2000-02-01), None
Search Report for EP 01 00 0095 dated Sep. 17, 2001.
Defieuw Geert
Hoogmartens Ivan
Loccufier Johan
Agfa-Gevaert
Hess Bruce
LandOfFree
Thermographic recording material with improved image tone does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thermographic recording material with improved image tone, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermographic recording material with improved image tone will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3292057