Thermal ink-jet head

An ink-jet recording apparatus comprising:

• a heater substrate having a plurality of bubble generating resistive elements;
• a channel substrate mounted over said heater substrate and having a plurality of nozzle channels, an ink reservoir, and an ink supplying opening,
• a sub-reservoir provided between and in communication with each of said nozzle channels of said channel substrate and said ink reservoir;
• a synthetic resin layer provided on said heater substrate;
• a plurality of first grooves on said layer for coupling each of said nozzle channels and said sub-reservoir, each of said first grooves corresponding at least to a nozzle channel formed on said channel substrate;
• and
• a plurality of second grooves on said layer for coupling said ink reservoir and sub-reservoir.

A thermal ink-jet head comprising:

• a heater substrate having a plurality of bubble generating resistive elements;
• a channel substrate mounted over said heater substrate and having a plurality of nozzle channels, and an ink reservoir, said nozzle channels each being formed in said channel substrate over a corresponding one of the bubble generating resistive elements and extending from an end portion of said corresponding bubble generating resistive element toward said reservoir;
• a coupling flow channel in said channel substrate in communication with each of said nozzle channels, and providing flow communication between said plurality of nozzle channels and said ink reservoir, said coupling flow channel and said reservoir each extending along said channel substrate and having a wall therebetween;
• and
• a synthetic resin layer provided on said heater substrate, said synthetic resin layer having a plurality of a grooves formed therein for coupling said nozzle channels and said ink reservoir, each groove extending at least beneath a corresponding nozzle channel from said bubble generating element to a position where said groove is coupled to said coupling flow channel, wherein each of said grooves has a sectional area which is reduced along the direction of orientation of said corresponding nozzle channel in the distance from the bubble generating resistive element up to the flow channel, and each of said plurality of nozzle channels has a tilted surface, the area of which is expanded both in the direction of orientation of said nozzle channel and in a direction perpendicular to the direction of orientation of said nozzle channel.