Browse Prior Art Database

Automatic Carrier Speed Adjustment

IP.com Disclosure Number: IPCOM000100355D
Original Publication Date: 1990-Apr-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Matsukawa, T: AUTHOR [+2]

Abstract

Disclosed is a method to adjust the carrier speed of serial printers automatically by the printer control software. In a high speed printer, the stability of the carrier speed is getting to be more important for print quality. However, the actual carrier speed is different from the desired speed because of: - the mechanical variations between printers - the mechanical change in a machine with the lapse of time, and - the changes of temperature - media condition

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 56% of the total text.

Automatic Carrier Speed Adjustment

       Disclosed is a method to adjust the carrier speed of
serial printers automatically by the printer control software.  In a
high speed printer, the stability of the carrier speed is getting to
be more important for print quality.  However, the actual carrier
speed is different from the desired speed because of:
      - the mechanical variations between printers
      - the mechanical change in a machine with the lapse of time,
and
      - the changes of temperature - media condition

      The method is effective in all of above cases without
additional hardware support and cost.  In a microprocessor-controlled
DC servo motor system, the carrier position can be tracked using some
mechanism, such as encoder pulse feedback.  Thus, the actual carrier
speed can be measured by the following steps (see the figure):
      1. Start the timer at point A
      2. Read the timer value at point B
      3. Calculate TAB (actual time from A to B)

      To make the program simple, the distance from A to B is fixed
not to cause timer overflow.  In the constant velocity area, T (time
for the fixed distance) is nearly proportional to the speed parameter
P which is output of the microprocessor and directly controls the
motor off duration in the Pulse Width Modulated (PWM) control system.
Thus, the following equation is valid.
   T = k*P + c                   (1) where k and c are const...