| 摘要 |
An image forming apparatus includes: and a unit that electrically shuts off a pressure generating unit corresponding to a nozzle ejecting no droplet, from a drive waveform generating unit for a period of a time Tb satisfying a relation Tb≧T2, and that applies, at a time after the shutoff, a voltage of a potential V1 to the pressure generating unit, where a potential serving as a reference for the drive waveform is denoted as V1, a minimum potential difference from the potential V1 required to displace a pressure generating unit to vibrate a meniscus with ejecting no liquid droplet from a nozzle is denoted as ΔV2, a time required for a potential to drop by the potential difference ΔV2 due to self-discharge after a pressure generating unit is charged to a predetermined potential is denoted as T2. |
| 主权项 |
1. An image forming apparatus comprising:
a print head including a plurality of nozzles configured to eject droplets of liquid and a plurality of pressure generating units configured to generate pressure to eject the droplets of liquid from the plurality of nozzles, the plurality of pressure generating units being units in which self-discharge occurs; a drive waveform generating unit configured to generate a drive waveform applied to each of the plurality of pressure generating units in the print head; and a unit configured to, when one or more of the plurality of nozzles are not ejecting any droplet of liquid,
electrically shut off one or more of the plurality of pressure generating units corresponding to the one or more of the plurality of nozzles, from the drive waveform generating unit for a period of a time Tb that is equal to or greater than a time T2,maintain the drive waveform at a reference potential V1, andapply, at a time after the shutoff, the reference potential V1 to the one or more of the plurality of pressure generating units for a period of time that is less than the time T2, wherein a minimum potential difference from the reference potential V1 required to displace a pressure generating unit to vibrate a meniscus of one or more of the plurality of nozzles that are not ejecting any liquid droplet of liquid is denoted as ΔV2, a time required for a potential to drop by the minimum potential difference ΔV2 due to the self-discharge after a pressure generating unit is charged to a target electric potential is denoted as the time T2, a time, from an immediately preceding droplet of liquid ejection operation until an abnormality occurs in a next droplet of liquid ejection operation due to a dried liquid surface in one of the plurality of nozzles of the print head is denoted as a time Ta, a time to hold a state in which the drive waveform generating unit and the one or more of the plurality of pressure generating units are electrically shut off from each other is denoted as the time Tb, and the time Ta is greater than the time T2. |
