Patent ID: 6457793
Filing Date: 2002-10-01
Classification: B41J

Abstract:
An ink level indicating ink tank for an jet printing system, comprising:a housing having an interior; an ink retaining capillary volume in said interior of said housing, said capillary volume having a pressure that is less than ambient pressure; a thin capillary element in said interior of said housing in contact with said capillary volume; a fluid impermeable, light transmissive window separated from said thin capillary element for allowing optical detection of said thin capillary element; and said thin capillary element and said fluid impermeable, light transmissive window configured to form a region that is sealed from ambient pressure by said ink retaining capillary volume so long as said ink retaining capillary volume contains sufficient ink to prevent ambient pressure from being communicated to said region, said region having a pressure that is less than said pressure in said ink retaining capillary volume while said region is sealed from ambient pressure by said ink retaining capillary volume.