Dolev 800/800V/800V² - Assemblies
Dynamic Optics
Bow & Linearity Correction

Dynamic Optics (zoom image)

Bow Adjustment Jig

Bow Correction Jig - Assembled

Bow Adj Screws

Description
Bow and Linearity Measurement Procedure - (revised 8/93)
Bow Adjustment
Linearity Adjustment

Description

The instructions below are designed to help overcome distortions of drum bow

and linearity on the Dolev 800 Imagesetter. The new measurement kit uses a

modified microscope and a laptop computer to adjust for imperfections. Keep in

mind the following facts about bow and linearity:

There are 3 axes in the Dolev 800 optics sub-system. One is mechanical axis for the drum (center of the drum). The second is the optical axis which is the beam which exits from the lens housing assembly. The third is the Spinner axis which is in the center of the Penta Prism. Ideally, these three axes should be all on top of each other.

Bow Adjustment

Bow Adjustment Jig

Overview
Bow Adjustment Instructions
Test Check

Overview

If the optical axis is not parallel to the machine axis, a Bow Effect may result. This usually appears as a sine shape.

Before you start:

1. Expose a grid file (supplied by the factory on tape) and measure the grid. If the bow is within 50 µ (50 microns) error, the Dolev 800 is within specification.)
   
   
2. Check if the focus is good. If not, see Focus Adjustment Procedure.

Bow Adjustment Instructions

1. Open the right side door cover and the black lightproof cover.
   
   
2. Move the carriage (if it is not there) to the End position via the Diag./Utility.
   
   
3. Remove the shutter protector.
   
   
4. Secure the Dolev 800 Bow Adjustment Jig (Cat. No. 280B34187) on the carriage (the two screws holes are on top of the spinner housing holder). Insert the four adjustment screws into their holes in the Lens Housing Assembly.
   
   
5. Set the two dial indicators that are in the jig to zero when their points touch the lens housing outskirt. (Be sure to leave enough space to move the lens housing in both directions.)
   
   
6. Move the lens housing via the adjustment screws in the direction and according to the correction that was taken from the measuring instrument.

Test Check

Note: Remeber to remove the bow adjustment kit before exposing any file.

1. Expose a grid file and check that the bow is not greater than 50 µ. If not, repeat the adjustment procedure until a satisfactory result (less than or equal to 50 µ) has been achieved.
   
   
2. Dismantle the jig and put back the cover. Close the left side door.

Linearity Adjustment

Overview
Tools and Accessories
Linearity Adjustment Instructions

Overview

If the optical axis does not coincide with the drum mechanical axis, there is a need to adjust the linearity via the strobe board.

Before you start:

1. Check if the linearity adjustment was already performed and if the strobe table in the Dolev 800 is updated by the values taken.
   
   
2. If the table is set to zero, load onto the disk (supplied with the machine) the correct values and expose a grid. Measure it and if the grid is not correct, perform a new linearity adjustment.

Tools and Accessories

GRID Measurement tool kit (510L35842)

Linearity Adjustment Instructions

1. Check first that the Dolev 800 focus is correct. See Focus Adjustment Procedure.
   
   
2. Check that the Bow is less than or equal to 50 microns. If not, perform Bow Correction (see Bow Adjustment Procedure).
   
   
3. Expose a grid at resolution 100. (Factory files are in the Dolev 800 or on tape.)
   
   
4. Measure the grid.
   
   
5. If the linearity is less than or equal to 50 m, leave the table as it is. If not, load the NVM Parameters diskette from the measurement jig to the Dolev 800 and load the value into the NVM Tables.
   
   
6. Expose another grid and measure the result. Check the result to see if the grid error falls within the 50 m range. If not, repeat this procedure.