Patent ID: 7201459
Filing Date: 2007-04-10
Classification: B41J

Abstract:
1. An ink jet printer ejecting a plurality of kinds of ink droplets of different sizes from a single nozzle depending upon data to be printed, thereby forming an image on a prescribed recording medium using dots of sizes corresponding to the sizes of the ink droplets, comprising: an ink jet head for ejecting an image forming droplet and a smoothing droplet from a single nozzle based on data to be printed, the smoothing droplet being smaller than the image forming droplet, thereby printing dots of sizes corresponding to the sizes of the ink droplets on a prescribed recording medium; a smoother for performing a smoothing process using the smoothing droplet to form a smoothing dot, wherein the distance between a center of the smaller size smoothing dot and a center of an image forming dot is smaller than the pitch of the image forming dot, and a controller for controlling the smoother, thereby maintaining constant the speed of ejection of the ink droplet forming the smoothing dot and changing the timing of ejection of the ink droplet forming the smoothing dot, by ejecting the smoothing droplet at the same speed as that of the image forming droplet; wherein the ink ejection is performed using a piezoelectric element, and a drive waveform applied to the piezoelectric element in ejecting image forming droplets is different from a drive waveform applied to the piezoelectric element in ejecting smoothing droplets.