Claims
- 1. A composite ink pad comprising:
- a porous pad comprising a thermoplastic, nonelastomeric resin having a microporous open cell structure housing a quantity of ink; and
- a nonelastomeric reservoir liner in substantial contact with one side of said ink pad, said reservoir liner having a microporous open cell structure, wherein the average pore diameter of the reservoir liner is greater than the average pore diameter of the ink pad,
- said reservoir liner capable of absorbing at least a portion of ink leaking from said pad when the pad is exposed to at least one of the two following conditions:
- (a) elevated ambient temperature higher than about 80.degree. F,
- (b) elevated humidity higher than about 80 percent humidity;
- said reservoir liner permitting the porous pad to reabsorb at least a portion of said ink from the liner upon reexposure of the pad to at least one of the two following normal ambient conditions:
- (a) ambient temperature less than about 70.degree. F.;
- (b) humidity less than about 80 percent relative humidity.
- 2. A composite ink pad as in claim 1 wherein the average pore diameter of the liner is at least 10 micrometers greater than the average pore diameter of the ink pad.
- 3. A composite ink pad as in claim 2 wherein the reservoir liner is fused to a substantial portion of at least one side of the ink pad.
- 4. A composite ink pad as in claim 3 wherein the reservoir liner becomes fused to the ink pad simultaneously with formation of the open cell pores in said ink pad.
- 5. A composite ink pad as in claim 4 wherein the open cell pores in the ink pad are formed by the process of:
- coating onto the reservoir liner a resin-ink dispersion comprising a thermoplastic resin having an average particle diameter between about 0.2 and 100 microns, a plasticizer, and an ink mixture comprising an ink pigment and ink vehicle, said ink vehicle being noncompatible with the thermoplastic resin, and
- heating the resin-ink coating and reservoir liner to form a rigid structure fused to said reservoir liner.
- 6. A composite ink pad as in claim 5 wherein the average particle diameter of the resin is between about 0.2 and 25 microns.
- 7. A composite ink pad as in claim 2 wherein the average pore diameter of the ink pad is in a range between about 5 to 50 micrometers.
- 8. A composite ink pad as in claim 7 wherein the average pore diameter of the ink pad is in a range between about 10 to 30 micrometers.
- 9. A composite ink pad as in claim 7 wherein the average pore diameter of the reservoir liner is as high as about 60 micrometers.
- 10. A composite stamp pad as in claim 1 wherein the reservoir liner can absorb up to about 25 percent by weight of ink present in the ink pad.
- 11. A composite stamp pad as in claim 1 wherein the reservoir liner is thinner than the stamp pad.
- 12. A composite stamp pad as in claim 11 wherein the stamp pad has a thickness of between about 0.1 and 0.4 inches.
- 13. A composite stamp pad as in claim 1 wherein the reservoir liner comprises heat resistant material which does not shrink, expand, or deteriorate when exposed to elevated temperatures up to about 160.degree. C.
- 14. A composite stamp pad as in claim 13 wherein the reservoir liner comprises a fibrous material.
- 15. A composite stamp pad as in claim 14 wherein the reservoir liner comprises fiberglass.
- 16. A composite ink pad comprising:
- a porour pad comprising a thermoplastic, nonelastomeric resin having a microporous open cell structure housing a quantity of ink; and
- a nonelastomeric reservoir liner in substantial contact with one side of said ink pad, said reservoir liner having a microporous open cell structure, wherein the average pore diameter of the reservoir liner is greater than the average pore diameter of the ink pad;
- the average pore diameter of the ink pad being in a range between about 5 to 50 micrometers, the average pore diameter of the reservoir liner being at least 10 micrometers greater than the average pore diameter of the ink pad, and the average pore diameter of the reservoir liner having a maximum value of about 60 micrometers;
- said reservoir liner capable of absorbing at least a portion of ink leaking from said pad when the pad is exposed to at least one of the two following conditions:
- (a) elevated ambient temperature higher than about 80.degree. F.;
- (b) elevated humidity higher than about 80 percent humidity;
- said reservoir liner permitting the porous pad to reabsorb at least a portion of said ink from the liner upon reexposure of the pad to at least one of the two following normal ambient conditions:
- (a) ambient temperature less than about 70.degree. F.;
- (b) humidity less than about 80 percent relative humidity.
BACKGROUND OF THE INVENTION
This application is a continuation-in-part of patent application Ser. No. 407,367 filed Aug. 12, 1982, now abandoned.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
2392521 |
Chollar |
Jan 1946 |
|
2777824 |
Leeds |
Jan 1957 |
|
3851619 |
Cofield, Jr. et al. |
Dec 1974 |
|
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
407367 |
Aug 1982 |
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