Patent ID: 6048059
Filing Date: 2000-04-11
Classification: B41J

Abstract:
An ink jet printer having means for preheating a recording medium prior to entry into a print zone of the printer, comprising:a printhead located at said print zone for depositing ink droplets on the recording medium as the recording medium moves through said print zone;means for moving the recording medium from a supply tray to a drive roller located adjacent the print zone, the moving means moving the recording medium at a first rate of speed;said drive roller being adapted to advance the recording medium through the print zone at a second rate of speed which is slower than the first rate of speed;a variable power preheater disposed adjacent the drive roller such that the drive roller is located between the preheater and print zone, with the print zone being downstream from the preheater, the preheater heating the recording medium as the recording medium moves there past;a first sensor for detecting the presence of the recording medium as the recording medium moves from the supply tray and for generating a first signal;a power supply for applying power to said preheater;a controller for varying the power output of said power supply so as to supply a first power input to the preheater in response to receipt of the first signal from the first sensor;a second sensor for detecting the presence of the recording medium upon arrival of the recording medium at the drive roller and for generating a second signal; andsaid controller varying the power output of said power supply so as to supply a second power input to the preheater in response to receipt of the second signal from the second sensor, the second power input being lower than the first power input, so that a portion of the recording medium is not overly preheated while the drive roller advances the recording medium through the print zone at said second rate of speed.