Patent ID: 9073315
Filing Date: 2015-07-07
Classification: B41J

Abstract:
1. An image forming apparatus, comprising: a liquid ejection head including a plurality of nozzles configured to eject a liquid droplet, an individual liquid chamber with which the nozzles communicate, and a pressure generation unit configured to generate a pressure for pressurizing a liquid in the individual liquid chamber; and a head drive control unit configured to wherein the drive waveform includes a first pulling-in waveform element to be selected first when liquid droplets of two or more droplet sizes are ejected, the first pulling-in waveform element being a waveform element that allows the individual liquid chamber to expand to an expanding state smaller than before start of contraction for droplet ejecting, wherein the drive pulse that is selected following the first pulling-in waveform element and serves as a first ejection pulse for ejecting the liquid droplet includes an expanding waveform element that allows the individual liquid chamber having expanded in the first pulling-in waveform element to expand to the expanding state before start of contraction for droplet ejecting, and a contracting waveform element that allows the individual liquid chamber to contract, wherein (N−⅓)Tc≦T wherein a time from the expansion start point of the individual liquid chamber in the first pulling-in waveform element to the contraction start point of the individual liquid chamber in the first ejection pulse when a liquid droplet having one of two droplet sizes is formed falls within a range of 1.0×Tc to 1.5×Tc, and wherein a time from the expansion start point of the individual liquid chamber in the first pulling-in waveform element to the contraction start point of the individual liquid chamber in the first ejection pulse when a liquid droplet having the other of the two droplet sizes is formed falls within a range of 2.0×Tc to 2.5×Tc.