Ink jet recording apparatus with a thermally stable ink jet recording head

An ink jet recording apparatus comprising:

• a recording head of a full-line type having a plurality of discharge ports provided across a recording medium, a liquid path communicated with said discharge ports and having a thermal energy generating member for generating energy utilized to discharge recording liquid, and a common liquid chamber for storing liquid to be supplied to said liquid path, wherein said energy generating member, said liquid path and said common liquid chamber are disposed on one side of a substrate;
• a chamber disposed on an area which is on a reverse side of said substrate with respect to said one side of said substrate and opposed to said energy generating member through said substrate, and extending along the longitudinal direction of said recording head for containing moving liquid therein, said chamber being provided independently from said common liquid chamber,
• wherein a first liquid flow is formed in a first direction with respect to an arrangement direction of said thermal energy generating member in said common liquid chamber, and a second liquid flow is formed in a second direction opposite to said first direction in said chamber;
• a temperature sensor which detects the temperature of said recording head during recording wherein the moving liquid forming the second liquid flow is circulated in the second direction when said temperature sensor detects that the temperature of said recording head exceeds a predetermined temperature;
• and
• fan means for supplying cooling air in response to the circulation of the moving liquid in the second flow.

A recording head comprising:

• a plurality of heat generating elements provided in a predetermined distribution to record by generating heat;
• a liquid path, having said heat generating elements therein, for guiding recording liquid discharged from a discharge port by utilizing thermal energy generated by said heat generating elements;
• a first flow path communicating with said liquid path to supply the recording liquid to said liquid path, for forming a first liquid flow in a direction across said liquid path;
• a second flow path provided independently from said first flow path through a substrate containing said heat generating elements, for forming a second liquid flow of moving liquid in a direction opposite to the direction of said first liquid flow;
• a temperature sensor which detects the temperature of said recording head during recording, wherein the moving liquid forming the second liquid flow is circulated within the second flow path when said temperature sensor detects that the temperature of said recording head exceeds a predetermined temperature;
• and
• fan means for supplying cooling air in response to the circulation of the moving liquid in the second flow path.

A method for controlling the temperature of a recording head which utilizes heat for recording, said method comprising the steps of:

• recording using said recording head;
• supplying recording liquid stored in a common liquid chamber to discharge ports of said recording head by way of a liquid path, said common liquid chamber and liquid path disposed on one side of a substrate;
• detecting a temperature change of said recording head during said recording;
• selectively circulating a moving liquid within a secondary chamber on a back side of the substrate without interrupting recording by said recording head and circulating said moving liquid within said secondary chamber and said recording liquid within said common liquid chamber while interrupting recording by said recording head, in order to cool said recording head when the temperature rises above a predetermined range;
• and
• supplying air to remove heat from said moving liquid when said moving liquid is circulated.