Patent ID: 6174037
Filing Date: 2001-01-16
Classification: B41J

Abstract:
A multiple pass ink jet printer with a power supply having reduced peak power in which liquid ink droplets are deposited on a recording medium in swaths to form an ink image in response to image data received thereby, comprising:a translatable printhead with at least one ink supply tank, the printhead having a plurality of nozzles and selectively addressable heating elements for ejecting ink droplets from the nozzles;means to translate the printhead back and forth across the recording medium at a constant speed;a power supply having a selected maximum power rating that is less than that required to print ink images having high ink density;a central processing unit with a memory containing information on power requirement behavior for said heating elements and said selected power supply maximum power rating, the central processing unit coupling the power supply to the printhead heating elements for effecting droplet ejection and for controlling the means to translate the printhead;a print power regulation circuit for receiving image data and determining an ink density per swath required to be printed by the printhead to produce an ink image of said image data on the recording medium, the print power regulation circuit sending a signal indicative of said required ink density per swath to be printed by the printhead to the central processing unit; andsaid central processing unit determining the number of printhead passes required to print a complete swath of the ink image upon receipt of the signal from the print power regulation circuit by using the information in said memory for the power requirement behavior for the heating elements and the selected maximum power rating of the power supply, so that the power required for the heating elements during any one pass of the printhead while printing a swath does not exceed the selected maximum power rating of the power supply, and said central processing unit causing the means to translate the printhead to effect the determined number of passes to print the swaths and to selectively address the printhead heating elements to form the ink image on the recording medium.