Ink jet head unit and ink jet printing apparatus incorporating the same

An ink jet head unit for performing color printing by using a plurality of ink nozzle arrays each for use in printing one line, the plurality of ink nozzle arrays corresponding to a plurality of basic colors,

• the ink jet head unit comprising:
• a plurality of head groups each formed by a plurality of ink jet heads, and having the plurality of ink nozzle arrays arranged therein such that the plurality of ink nozzle arrays are divided among the plurality of head groups;
• a plurality of sub-carriages having respective ones of said plurality of head groups mounted thereon;
• and
• a unitizing carriage having said plurality of sub-carriages mounted thereon;
• wherein the plurality of sub-carriages are arranged in a manner staggered from each other on said unitizing carriage;
• wherein each of the ink jet heads comprises a head base plate, and a head body arranged in one substantial half of the head base plate toward one longitudinal side, the head body having a corresponding portion of the plurality of ink nozzle arrays arranged therein, and
• wherein in each two of the plurality of head groups, adjacent to each other with respect to a direction along the line, the head body of each of the plurality of ink jet heads of one of the two head groups and the head body of each of the plurality of ink jet heads of another of the two head groups are arranged opposed to each other in a back-to-back fashion.

An ink jet head unit for performing color printing by using a plurality of ink nozzle arrays each for use in printing one line, the plurality of ink nozzle arrays corresponding to a plurality of basic colors,

• the ink jet head unit comprising:
• a plurality of head groups each formed by a plurality of ink jet heads, and having the plurality of ink nozzle arrays arranged therein such that the plurality of ink nozzle arrays are divided among the plurality of head groups;
• a plurality of sub-carriages having respective ones of said plurality of head groups mounted thereon;
• and
• a unitizing carriage having said plurality of sub-carriages mounted thereon;
• wherein said unitizing carriage has a plurality of positioning pin groups provided on a surface thereof, for enabling each of said plurality of sub-carriages to be mounted in a positioned state, and
• wherein each of said positioning pin groups positions a corresponding one of said plurality of sub-carriages on said unitizing carriage, with reference to a reference position set to a position of an outermost ink nozzle of an arbitrary one of the plurality of ink jet heads mounted on the corresponding one of said plurality of sub-carriages.

An ink jet head unit for performing color printing by using a plurality of ink nozzle arrays each for use in printing one line, the plurality of ink nozzle arrays corresponding to a plurality of basic colors,

• the ink jet head unit comprising:
• a plurality of head groups each formed by a plurality of ink jet heads, and having the plurality of ink nozzle arrays arranged therein such that the plurality of ink nozzle arrays are divided among the plurality of head groups;
• a plurality of sub-carriages having respective ones of said plurality of head groups mounted thereon;
• and
• a unitizing carriage having said plurality of sub-carriages mounted thereon;
• wherein said unitizing carriage has a plurality of positioning pin groups provided on a surface thereof, for enabling each of said plurality of sub-carriages to be mounted in a positioned state;
• wherein each of said positioning pin groups positions a corresponding one of said plurality of sub-carriages on said unitizing carriage, with reference to a reference position set to a position of an outermost ink nozzle of an arbitrary one of the plurality of ink jet heads mounted on the corresponding one of said plurality of sub-carriages;
• and
• wherein said each of said positioning pin groups comprises:
• a reference pin arranged in a manner corresponding to the reference position;
• an angle-limiting pin for positioning the corresponding one of said plurality of sub-carriages in a direction of rotation thereof about said reference pin on said unitizing carriage;
• an X-axis direction urging pin for urging the corresponding one of said plurality of sub-carriages in an X-axis direction toward said reference pin to thereby position the corresponding one of said plurality of sub-carriages in a Y-axis direction perpendicular to the X-axis direction;
• and
• a Y-axis direction urging pin for urging the corresponding one of said plurality of sub-carriages in said Y-axis direction toward said reference pin to thereby position the corresponding one of said plurality of sub-carriages in said X-axis direction.

An ink jet printing apparatus including an ink jet head unit for performing color printing by using a plurality of ink nozzle arrays each for use in printing one line, the plurality of ink nozzle arrays corresponding to a plurality of basic colors,

• the ink jet head unit comprising:
• a plurality of head groups each formed by a plurality of ink jet heads, and having the plurality of ink nozzle arrays arranged therein such that the plurality of ink nozzle arrays are divided among the plurality of head groups;
• a plurality of sub-carriages having respective ones of said plurality of head groups mounted thereon;
• and
• a unitizing carriage having said plurality of sub-carriages mounted thereon;
• wherein the plurality of ink nozzle arrays are each divided into a plurality of divisional ink nozzle arrays with respect to a direction along the one line, and are grouped into a plurality of divisional ink nozzle array groups each formed of corresponding ones of said plurality of divisional ink nozzle arrays, and wherein the plurality of ink jet heads of each of said plurality of head groups have the plurality of divisional ink nozzle arrays of a corresponding one of the plurality of divisional ink nozzle array groups arranged therein such that the plurality of divisional ink nozzle arrays are divided among the plurality of ink jet heads.