Liquid discharge head and printer

Abstract

A liquid discharge head includes first and second actuators and a drive circuit. Each of the first and second actuators is configured to expand and contract first and second pressure chambers, respectively. The drive circuit is configured to, during a dot formation cycle apply a first number of discharge pulses to the first actuator to cause the first number of droplets to be discharged from the first pressure chamber and apply a second number of discharge pulses to the second actuator to cause the second number of droplets to be discharged from the second pressure chamber and apply a third number of precursors to the second actuator. The first number is greater than or equal to two. Each of the second and third numbers is greater than or equal to one. A sum of the second and third numbers is less than or equal to the first number.

What is claimed is: 
     
         1 . A liquid discharge head comprising:
 an actuator configured to expand and contract a pressure chamber corresponding thereto; and   a drive circuit configured to, during a dot formation cycle, apply a first number of discharge pulses to the actuator to cause the first number of droplets to be discharged from the pressure chamber and apply a second number of precursors to the actuator, the first number being equal to or more than one and the second number being equal to or more than one.   
     
     
         2 . The liquid discharge head according to  claim 1 , wherein a sum of the first number and the second number is equal to a maximum number of discharge pulses the drive circuit is capable of applying to the actuator during the dot formation cycle. 
     
     
         3 . The liquid discharge head according to  claim 1 , further comprising:
 a second actuator configured to expand and contact a second pressure chamber corresponding thereto, wherein   the drive circuit is configured to, during the dot formation cycle, apply a third number of discharge pulses to the second actuator to cause the third number of droplets to be discharged from the second pressure chamber, the third number being different from the first number.   
     
     
         4 . The liquid discharge head according to  claim 3 , wherein the drive circuit applies one of the second number of precursors in synchronization with one of the third number of discharge pulses. 
     
     
         5 . The liquid discharge head according to  claim 4 , wherein
 each of the second number of precursors includes an expansion pulse,   each of the third number of discharge pulses includes an expansion pulse, and   the drive circuit applies the expansion pulse of the one of the second number of precursors in synchronization with the expansion pulse of the one of the third number of discharge pulses.   
     
     
         6 . The liquid discharge head according to  claim 1 , wherein
 each of the first number of discharge pulses includes an expansion pulse having a first pulse width to cause expansion of the pressure chamber from a neutral state, and   each of the second number of precursors includes an expansion pulse having a second pulse width to cause expansion of the pressure chamber from a neutral state, the second pulse width being less than the first pulse width.   
     
     
         7 . The liquid discharge head according to  claim 6 , wherein the first pulse width is more than twice the second pulse width. 
     
     
         8 . The liquid discharge head according to  claim 1 , wherein each of the second number of precursors includes an expansion pulse to cause expansion of the pressure chamber from a neutral state, and includes no contraction pulse to cause contraction of the second pressure chamber from the neutral state. 
     
     
         9 . The liquid discharge head according to  claim 1 , wherein each of the second number of precursors includes a contraction pulse to cause contraction of the second pressure chamber from a neutral state and includes no expansion pulse to cause expansion of the second pressure chamber from the neutral state. 
     
     
         10 . The liquid discharge head according to  claim 1 , wherein each of the second number of precursors has a pulse width greater than 0.1 times a natural vibration period of the pressure chamber. 
     
     
         11 . The liquid discharge head according to  claim 1 , wherein the drive circuit applies the second number of the precursors to the actuator after applying all of the first number of discharge pulses to the actuator. 
     
     
         12 . The liquid discharge head according to  claim 1 , wherein the drive circuit applies the first number of discharge pulses to the actuator after applying all of the second number of precursors to the actuator. 
     
     
         13 . The liquid discharge head according to  claim 1 , wherein the drive circuit at least partially applies alternately the first number of discharge pulses and the second number of precursors to the actuator. 
     
     
         14 . The liquid discharge head according to  claim 1 , wherein application of the second number of precursors to the actuator causes no droplet discharge from the pressure chamber. 
     
     
         15 . The liquid discharge head according to  claim 1 , wherein the drive circuit is further configured to, during another dot formation cycle, apply a third number of discharge pulses to the actuator to cause the third number of droplets to be discharged from the pressure chamber and apply a fourth number of precursors to the actuator, the third number being different from the first number and the fourth number being different from the second number. 
     
     
         16 . A printer comprising:
 a medium conveyer;   a liquid discharge head configured to discharge droplets of liquid to a medium conveyed by the medium conveyer, the liquid discharge head including an actuator configured to expand and contract a pressure chamber corresponding thereto; and   a drive circuit configured to, during a dot formation cycle, apply a first number of discharge pulses to the actuator to cause the first number of droplets to be discharged from the pressure chamber and apply a second number of precursors to the actuator, the first number being equal to or more than one and the second number being equal to or more than one.   
     
     
         17 . The printer according to  claim 16 , wherein a sum of the first number and the second number is equal to a maximum number of discharge pulses the drive circuit is capable of applying to the actuator during the dot formation cycle. 
     
     
         18 . The printer according to  claim 16 , wherein
 the liquid discharge head further includes a second actuator configured to expand and contact a second pressure chamber corresponding thereto, and   the drive circuit is configured to, during the dot formation cycle, apply a third number of discharge pulses to the second actuator to cause the third number of droplets to be discharged from the second pressure chamber, the third number being different from the first number.   
     
     
         19 . The printer according to  claim 18 , wherein the drive circuit applies one of the second number of precursors in synchronization with one of the third number of discharge pulses. 
     
     
         20 . The printer according to  claim 19 , wherein
 each of the second number of precursors includes an expansion pulse,   each of the third number of discharge pulses includes an expansion pulse, and   the drive circuit applies the expansion pulse of the one of the second number of precursors in synchronization with the expansion pulse of the one of the third number of discharge pulses.