Printing (300 X 300 Dpi) - Tektronix Phaser 360 Service Manual

5
Theory of Operation
5-20 Phaser 360 Color Printer
At this point, the drum starts rotating again at 190 rpm. As the drum reaches the
correct speed, the ink-jets begin to fire to deposit the image on the oiled portion
of the drum. As the jets fire, the printhead slews in the x-axis to complete the
image on the drum. When the ink image is about 80% complete, the paper-pick
cycle begins. As the jets fire, the printhead slews in the x-axis to complete the
image on the drum.

Printing (300 x 300 dpi)

When printing, the printer performs a "four-jet interlace."in which, each jet lays
down 28 pixel columns. Each jet lays down one pixel column for each drum
rotation (28 revolutions total). Each jet travels horizontally the distance of
117 pixels to lay down its 28 pixel columns within that 117 pixel-wide field. The
117 pixel-wide field of each jet overlaps the 117 pixel-wide field of six other jets;
this is where interlacing occurs. To lay down its 28 pixel columns, each jet
follows this sequence:
1.
Print 1st column, step four columns to the right, print 2nd column,
step four columns to the right. Repeat until 7 columns are laid down.
The 7th column also includes a four step movement to the right.
2. Step 2 additional columns to the right.
3. Print the 8th column, step 4 columns to the right, print 9th column,
step 4 columns to the right. Repeat until 7 columns are laid down
(total of 14 so far). The 14th column also includes a four step
movement to the right.
4.
Step 1 additional column to the right.
5. Print the 15th column, step 4 columns to the right, print the 16th
column, step 4 columns to the right. Repeat until another 7 columns
are laid down (21 total so far). The 21th column also includes a four
step movement to the right.
6. Step 2 additional columns to the right.
7. Print the 22nd column, step 4 columns to the right, print the 23rd
column, step 4 columns to the right. Repeat until the last 7 columns
are laid down for a total of 28 pixel columns.
The intermediate 2-step, 1-step and 2-step movement between the 7th and 8th
pixel columns, the 14th and 15th columns, and the 21st and 22nd columns,
respectively, allow the 28 pixels columns of each jet to properly interlace with
the 28 pixel columns of the other jets it is combined with. A total of
2,432 columns, each 3,134 dots tall, are laid down.