Patent ID: 7416269
Filing Date: 2008-08-26
Classification: B41J

Abstract:
1. An ink jet printer, comprising: an ink jet head including a nozzle, an ink chamber communicating with the nozzle, a pressure chamber located between the nozzle and the ink chamber, and an actuator that changes volume of the pressure chamber; a controller that controls the actuator to perform a first performance, the first performance including a first change in which the volume of the pressure chamber increases, and a second change in which the volume of the pressure chamber decreases; and a transferring device that transfers at least one of the ink jet head and a print medium along a predetermined direction in a state in which the nozzle faces the print medium, wherein a period from the first change to the second change is 2/3×AL or below, or within a range between (2s−1/2)×AL and (2s+2/3)×AL, s is a positive integer, discharging speed of ink discharged from the nozzle is substantially maximum if the period from the first change to the second change is set to AL, the controller is capable of controlling the actuator to perform a second performance, the second performance includes a third change in which the volume of the pressure chamber increases, and a fourth change in which the volume of the pressure chamber decreases, a period from the third change to the fourth change is within a range between (2t−4/3)×AL and (2t−1/2)×AL, and t is a positive integer, the ink jet printer prints on the print medium by repeating a unit period while the transferring device transfers the ink jet head or the print medium along the predetermined direction, the controller controls the actuator to perform either the first performance or the second performance in each unit period, the nozzle discharges ink to form one dot when the actuator performs the second performance in one unit period, and the nozzle does not discharge ink when the actuator performs the first performance in one unit period.