Applies to

• Lotem^® 800
• Lotem 400
• Lotem XL
• Lotem 400 Xpose
• ThermoFlex Mid/Narrow

Priority: Next failure
Release date: 10 May 2005
Document: 719-00494A Rev A

Problem

The existing optic house opening (where the resolution mechanism fork enters the optic head), is too large. Dust can easily enter through this opening and damage the laser optics, resulting in reduced image quality.

Solution

Prevent dust from reaching the laser optics by sealing the opening where the resolution mechanism fork enters the optic house.

Time needed to implement

1 day (to include the readjustment of the fiber head for good quality images).

Parts needed

Special Tools needed

Loctite 242
Cotton swabs

Procedure

The procedures for sealing the optic house opening comprise of three steps:

• Cleaning the optical V-groove assembly
• Disconnecting the old resolution assembly
• Constructing and connecting the new resolution assembly

Note: Before beginning the procedure, expose a reference plate and put it to one side. After completing the procedure, you will expose a further reference plate and compare it with this plate.

Cleaning the optical V-groove assembly
Refer to the clean the optical V-groove assembly document and complete the following procedural steps of the document:

• Tightening the Lens, steps 1-10 (inclusive)
• Reassembling the lens and testing, steps 1-5 (inclusive)

Disconnecting the old resolution assembly
After cleaning the optical V-groove assembly, the second step involves disconnecting the old resolution assembly:

1. Move the carriage to 500 mm.
2. Open the platesetter's rear door via Lotem Controller.
3. Remove the rear upper panel and take out the unload tray.
4. Shut down the platesetter via Lotem Controller.
5. Disconnect the power cable, the detector cables and the ground cable from the motor resolution:

   
   

6. Undo the four resolution motor screws with a #8-32" hex key and remove the motor:

   
   

7. Undo the two bracket connector screws with a #6-32" hex key and remove the bracket:

   
   

8. On the holder resolution assembly, undo the shoulder screw with an #4-40 L-hex key and undo the second screw with a #8 hex key. Remove the holder resolution assembly:

   
   

9. Disconnect the two springs attached to the fork:

   
   

10. Using a straight head screwdriver, undo the fork screw and then remove the fork from the optic house:

    
    

Constructing and connecting the new resolution assembly

1. Lightly dip a cotton swab in acetone and gently clean the optic house opening:

   
   
   Important: Do not insert the cotton swab into the optic house.

2. Make sure the optic house and all the FCO parts are clean and free of dust.
3. Place the following new parts onto the stem of the fork assembly:
   • Washer 0.8 (part no. 252-01714A)
   • Comp. spring (part no. 318-00036)
   • Washer 0.8 (part no. 252-01714A)
   • O-ring (part no. 316-00036)

   

4. Place the new resolution cover (part no. 252-01715A) over the optic house opening (where the resolution mechanism fork enters the optic head):

   
   

5. Put Loktite 242 on the end of the fork and then insert the fork through the hole of the resolution cover and into the optic head. Tighten the fork screw with a straight head screwdriver. Make sure the fork can freely move up and down.
6. Reattach the two springs to the new fork.
7. Place the new resolution holder (part no. 252-01715A) onto the optic head:

   
   

   Attach the resolution holder to the optic head with a shoulder screw and a #8 screw. Once again, make sure the fork can freely move up and down. If the fork's movement is not smooth, undo the resolution holder and reattach it.

8. Using a #6-32" hex key, reattach the bracket connector with two screws.
9. Using a #8-32" hex key, reattach the resolution motor with four screws.
10. Reconnect the power cable, the detector cables and the ground cable to the motor resolution.
11. Reinstall the unload tray.
12. Reinstall the rear upper panel.
13. Close the rear door.

When done

1. Start up the platesetter via Lotem Controller.
2. Recallibrate the head: Perform focus test, elevation, resolution, intensity and delay.
3. Expose a reference plate and compare the image quality to an earlier reference plate.

Logistics

Approved quantities:

Schedule supplies for first lots:

See also

Cleaning the Optical V-groove Assembly procedures

Technical contact

Yaron Shifman

Product Support Manager: Yaron Sofer

Date submitted