Image forming apparatus and head drive method

Patent metadata

Field	Value
Publication number	US-9616662-B2
Application number	US-201514730423-A
Country	US
Kind code	B2
Filing date	Jun 4, 2015
Priority date	Jun 30, 2014
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

An image forming apparatus includes a liquid discharging head unit including multiple nozzles to discharge liquid droplets, individual liquid chambers communicated to the multiple nozzles, and pressure generating units to generate pressure applied to a liquid in the individual liquid chambers; and a head drive control unit to generate a common driving waveform including multiple discharging pulses arranged in time series within one driving cycle of discharging liquid droplets of the liquid, to select at least one of the multiple discharging pulses from the common driving waveform, and to apply the selected at least one of the discharging pulses to the pressure generating units. The common driving waveform, generated by the head drive control unit, include at least a first discharging pulse and a second discharging pulse for discharging liquid droplets of same size.

First claim

What is claimed is:

1. An image forming apparatus, comprising:
a liquid discharging head unit including multiple nozzles arranged in a predetermined nozzle arrangement direction to discharge liquid droplets, individual liquid chambers communicated to the multiple nozzles, and pressure generating units to generate pressure applied to a liquid in the individual liquid chambers; and
a head drive control unit to generate a common driving waveform including multiple discharging pulses arranged in time series within one driving cycle of discharging liquid droplets of the liquid, to select at least one of the multiple discharging pulses from the common driving waveform, and to apply the selected at least one of the discharging pulses to the pressure generating units,
wherein the common driving waveform, generated by the head drive control unit, includes at least a first discharging pulse and a second discharging pulse, which occurs in time series to, and not overlapping with, the first discharging pulse within the same driving cycle of the common driving waveform, for discharging liquid droplets of same size, and
when discharging liquid droplets of the same size from two adjacent nozzles of the multiple nozzles that are adjacent in the predetermined nozzle arrangement direction, the head drive control unit applies the first discharging pulse to the pressure generating unit of one nozzle of the adjacent nozzles and applies the second discharging pulse, which is in time series to, and not overlapping with, the first discharging pulse within the same driving cycle of the common driving waveform, to the pressure generating unit of the other nozzle of the adjacent nozzles, and
wherein the liquid droplets discharged with the first discharging pulse and the liquid droplets discharged with the second discharging pulse impact an impacting surface at the same time.

2. The image forming apparatus of claim 1 , wherein when the multiple nozzles are classified into odd number nozzles and even number nozzles, the head drive control unit applies the first discharging pulse to the pressure generating units of either the odd number nozzles or the even number nozzles and the second discharging pulse to the pressure generating units of the remaining odd number nozzles or the even number nozzles.

3. The image forming apparatus of claim 1 , wherein when the adjacent nozzles of the multiple nozzles are classified into a discharging nozzle and an non-discharging nozzle, the head drive control unit applies the first discharging pulse to the pressure generating unit of either the discharging nozzle or the non-discharging nozzle and the second discharging pulse to the pressure generating unit of the remaining discharging nozzle or the non-discharging nozzle.

4. The image forming apparatus of claim 1 , wherein the first discharging pulse and the second discharging pulse cause the adjacent nozzles discharge liquid droplets of the smallest size, relatively.

5. The image forming apparatus of claim 1 , wherein whenever the first discharging pulse is being applied to the pressure generating unit of the one nozzle of the adjacent nozzles, the first discharging pulse is not applied to the pressure generating unit of the other nozzle of the adjacent nozzles, and whenever the second discharging pulse is being applied to the pressure generating unit of the other nozzle of the adjacent nozzles, the second discharging pulse is not applied to the pressure generating unit of the one nozzle of the adjacent nozzles.

6. A head drive method of driving a liquid discharging head unit including multiple nozzles arranged in a predetermined nozzle arrangement direction to discharge liquid droplets, individual liquid chambers communicated to the multiple nozzles, and pressure generating units to generate pressure applied to a liquid in the individual liquid chambers, the method comprising:
generating a common driving waveform including at least a first discharging pulse and a second discharging pulse, which occurs in time series to, and not overlapping with, the first discharging pulse within the same driving cycle of the common driving waveform, for discharging liquid droplets of same size; and
applying, when discharging liquid droplets of the same size from adjacent nozzles of the multiple nozzles that are adjacent in the predetermined nozzle arrangement direction, the first discharging pulse to the pressure generating unit of one nozzle of the adjacent nozzles and applying the second discharging pulse, which is in time series to, and not overlapping with, the first discharging pulse within the same driving cycle of the common driving waveform, to the pressure generating unit of the other nozzle of the adjacent nozzles,
wherein the liquid droplets discharged with the first discharging pulse and the liquid droplets discharged with the second discharging pulse impact an impacting surface at the same time.

7. The head drive method of claim 6 , wherein whenever the first discharging pulse is being applied to the pressure generating unit of the one nozzle of the adjacent nozzles, the first discharging pulse is not applied to the pressure generating unit of the other nozzle of the adjacent nozzles, and whenever the second discharging pulse is being applied to the pressure generating unit of the other nozzle of the adjacent nozzles, the second discharging pulse is not applied to the pressure generating unit of the one nozzle of the adjacent nozzles.

Assignees

• Kitaoka Naoko
• Yoshida Takahiro
• Ricoh Co Ltd

Inventors

• Kitaoka Naoko
• Yoshida Takahiro

Classifications

• B41J2/04588 Primary

  using a specific waveform · CPC title

• B41J2/04581

  controlling heads based on piezoelectric elements · CPC title

• B41J2202/20

  Modules · CPC title

• B41J2/04573

  Timing; Delays · CPC title