Product

• Kodak^® Lotem^® 400 FH family
• Kodak Magnus^™ 400 LDA family
• Kodak Magnus 400 II LDA family

Background

The objective of the delay calibration test is to calibrate the delay parameter for the Data Distribution Board (DDB) on Lotem 400 Xpose platesetters, and the Laser Diode Array (LDA) driver on Magnus 400 and Magnus 400 II family platesetters so that the exposed horizontal lines are perfectly straight.

Perform the test using a resolution of 100 dpm at different delay values. The optimal delay value is the delay value that appears on the best exposure.
Note: The delay test results do not depend on the plate type, size, or thickkness; perform the test on any plate that the customer uses.

Requirements

Tools:

• Densitometer
• Microscope
• Plates

Prerequisites:

• Focus value obtained in the Focus calibration test
• Elevation angle obtained in the the Elevation adjustment procedure
• Intensity value obtained in the Intensity calibration test
• Resolution value obtained in the Resolution calibration test

Procedure

To obtain the optimal delay value, perform the delay test twice: first to find the coarse delay value, and then to find the fine delay value.

1. Load a plate.
2. From the Kodak Xpo^™ palette, select Tools > Calibration.
   
   
   
   
3. In the Calibrate dialog box, perform the following steps:
   1. In the Calibration Type list, select Delay.
   2. In the Delay Value field, do not change this value until the optimal delay value has been determined. See Selecting the correct delay.
      Note: To load the last-saved delay test value, click Get.
   3. In the Test Delay Values [µm] area, in the From and To fields, type the test range for the delay stepper motor values. For best results, enter a range that is a few motor steps above and below the last-saved delay value—for example, 82 to 83.
   4. In the Number of Steps list, select the number of exposures to perform for the selected delay test range. For best results, use 11 steps.
      When you type a step value, the Lotem/Magnus 400 Controller software automatically calculates and displays the size of each step interval in the Size field, using the following formula:
      Step size = (To–From)/(Number of steps –1)
      Note: The interval value provides a quick reference for the platesetter operator, and cannot be changed.
   5. In the Resoluton list, select the resolution used by the customer.
   6. In the Test File list, select the TIF file that you want to use for the delay test.
      Note: Test files are predefined; the ones that appear in the list are according to the selected resolution.
   7. In the Current Plate list, select the plate that you are using for the test.
   8. In the Image Offset fields, type a value in millimeters for the horizontal offset (around the drum), and the vertical offset (along the drum).
      Note: The (0,0) offset coordinate is located at the upper-left corner of the plate.
      If you use the same plate for multiple tests, enter the appropriate offset values for each test.
   9. In the Plate Policy section, select or clear the Load and Unload check boxes that apply to focus test:
      • Load: Automatically loads a new plate before the test begins. To perform multiple calibration tests on the same plate, before you start the next test, clear this check box to reuse the plate.
      • Unload: Automatically unloads the plate after the test. To perform multiple calibration tests on the same plate, before you start the next test, clear this check box.
4. Click Test to start the delay test.
   The Lotem/Magnus 400 Controller software performs a series of exposures on the plate, after which you need to process the plate and examine the results.
   
5. Using a microscope, examine the results, and select the target strip that has the smoothest and most even horizontal lines.
   
   
   
   
6. Repeat steps 1 to 5 to find the fine delay value. In the Test Delay Values [µm] area, in the From and To fields, type the test range for the delay stepper motor values. For best results, refine the range that you used to find the coarse delay value—for example, 82.5 to 82.7.
   
   
   
   
7. In the Delay Value field, type the optimal delay value that appears inline with the target strip that returned the optimal results for the delay test, and click Save.

   The optimal delay value is transferred to the Lotem/Magnus 400 Controller software.
   Lotem/Magnus 400 Controller automatically calculates the optimal delay values for other resolutions.

Technical contact

Content owner: Mario Amir
See the Escalation page for escalation contacts.

Date submitted

11 Jun 2008