Loading and Unloading Sequences: Carrier and Proofing Media

Description

Proofing Media is more fragile than plates. Loaded directly on the drum, Proofing Media is trapped in the vacuum notches and the grippers. To prevent this, the Lotem Spectrum does not expose Proofing Media directly on the drum. Instead, a Carrier is loaded first and wrapped around the drum, providing a buffer against the harsh conditions. When switching from plate making to proof making, or vice versa, a Carrier must be loaded or unloaded from the drum.

Loading the Carrier

The Carrier is loaded from the upper tray of the Dual Loading Cassette (DLC).

Loading sequence:

Like the plate loading sequence, the Carrier loading sequence contains three stages. Two of the three loading stages are specific to the Carrier:

• Loading from Cassette to Punch Entry
• Loading from Punch Entry to Drum Entry

To access the relevant parameters: Hardware Tree>Loading System>Load Blanket.

Loading from Cassette to Punch Entry:

In this stage, the XY Loading Bar picks up the Carrier from the upper tray and moves it to the Punch Entry.

1. Place the Carrier on the upper tray so that the punch notch is located on the lower left side and the blue tape faces downwards.
2. Confirm that the XY Loading Bar does not touch the Proof Loading Bar when releasing the Carrier.
   If it does, increase the X Motor Pos To Punch parameter in the registry from the default of 138 to a value between 155-163.
   (Hardware>Loading System>Load Blanket>Blanket From Cassette To Punch Entry Stage>X Motor)
3. Confirm that the edge of the Carrier is under the Proof Loading Bar when it is first released from the XY Loading Bar. (Since both sides of the Carrier curl, if the Carrier is not under the Proof Loading Bar, it will touch the bar in the next stage.)
   If the edge of the Carrier is not under the Proof Loading Bar, increase the X Motor Pos To Catch Blanket parameter from the default of 370 to 375.
   (Hardware>Loading System>Load Blanket>Blanket From Cassette To Punch Entry Stage>X Motor)
   

Loading from Punch Entry to Drum Entry:

In this stage, the XY Loading Bar takes the Carrier from Punch Entry to Drum Entry. Note that the Carrier is already punched. Therefore, it is not centered to the short pins and is not punched.

• Note the position of X before Y moves up to the drum, and verify that the Carrier does not touch the Proof Loading Bar on its way to the drum.
  If it does, increase the X Motor Pos Back After Second Centering parameter from the default of 355 to a value between 358-360.
  (Hardware>Loading System>Load Blanket>Blanket From Punch Entry To Drum Entry Stage>X Motor)

Loading from Drum Entry to Drum:

In this stage, the XY Loading Bar takes the Carrier from Drum Entry into the Load Grippers.

This is the only stage in which Carrier loading is identical to plate loading. The parameters used for 300µ plates in this stage, including X In Drum, X In Drum Final, and so on, are the same as those used for Carrier loading. Because this stage for Carrier and plate loading is identical, after every adjustment of the parameters for plates, check to see if the new parameters work for Carriers, and vice versa.

If an attachment problem occurs, it is recommended to change the parameters in one of the two earlier stages. The best solution is to change the X Motor Pos To Catch Blanket parameter. Increase this value to increase the area of the Carrier that enters the Load Grippers, or decrease it to decrease the area of the Carrier that enters the Load Grippers.

Note: Changing this parameter may require changing the X Motor Pos Back After Second Centering parameter (default is 355) as mentioned in Step 2: Load From Punch Entry To Drum Entry stage.
If you change parameter in this third stage, be sure to test them on a trial plate when you switch to working with plates.

Unloading Sequence:

The Carrier unloading sequence is identical to the plate unloading sequence.

Proofing Media

Proofing Media is loaded from the proofing tray, which is placed on the upper tray of the DLC.

Loading sequence:

The loading sequence for Proofing Media, (Receivers and Donors), is similar to the loading sequence for plates and Carriers, but has only two stages:

• Loading from Cassette to Punch Entry
• Loading from Drum Entry to Drum Stage

The Loading From Punch Entry To Drum Entry stage is not necessary, because the media is not centered or punched.
The Receiver and Donor have different parameters, which are located in the same table.
(Hardware Tree>Loading System>Load Proof)

Loading from Cassette to Punch Entry:

In this stage, the XY Loading Bar picks up the media from the Proofing Tray and moves it to the Proof Loading Bar.

1. Confirm that the X Motor position is above the Proofing Tray (see Figure 1) and that the XY Suction Cups are above the Proof Loading Bar Suction Cups so that the vacuum from the Proof Loading Bar attaches the media.
   If the XY Suction Cups are not positioned properly, increase the X Motor Pos Above Load Bar parameter in the registry from the default of 89 to a value between 95-99.
   (Hardware Tree>Loading System>Load Proof>Blanket From Cassette To Punch Entry>X Motor)
   
   Figure 1: XY Suction Cups Above Proof Loading Bar Suction Cups

2. Confirm that the Y Motor descends to the Proof Loading Bar (see Figure 2) so that the vacuum from the Proof Loading Bar attaches the media.
   If the Y Motor is not close enough to the Proof Loading Bar, increase the pressure from the XY Suction Cups on the Proof Loading Bar Suction Cups by increasing the value of the Y Motor Pos Down to Load Bar parameter from the default of 30 to a value between 32-34.
   (Hardware Tree>Loading System>Load Proof>Blanket From Cassette To Punch Entry>Y Motor)
   
   Figure 2: Y Motor Descending to the Proof Loading Bar

Loading from Drum Entry to Drum Stage:

In this stage, the Proof Loading Bar attaches the Proofing Media to the drum.

1. Load the Receiver within the area marked by blue tape.
2. Load the Donor on top of the Receiver so that the edges of the Donor cover the blue tape.
3. Confirm that the Drum Motor is in the correct position for the Receiver and the Doner. (See Figure 3.)
   If the drum motor is not in the correct position for the Receiver or Donor:

• Receiver: Change the Drum Motor Position Ready for Receiver parameter from the default of -390 to -393. Test by performing a loading and if necessary, adjust the parameter.
• Donor: Change the Drum Motor Position Ready for Donor parameter from the default of -408 to -412. Test by perform a loading and if necessary, adjust the parameter.
  

Figure 3: Drum Motor Position Ready for Donor

4. If the Tail Grippers touch the Proof Loading Bar while it is activated and the drum is rotating, the Tail Grippers may be moved from their correct position.
   Confirm that the Tail Grippers do not touch the Proof Loading Bar at the end of the Proof Loading Sequence.
   If the Tail Grippers touch the Proof Loading Bar, increase the value of the Delay After Lowering Load Bar parameter from the default of 1000 to a value between 2000-3000.
   (Hardware Tree>Loading System>Load Proof>Proof From Drum Entry To Drum Stage>Delay>Delay After Lowering Load Bar)
   
   

Unloading sequence:

The unloading sequence of the Proofing Media is different from the unloading sequence of the Carrier or the plate, and has its own registry parameters.
(Hardware>Loading System>Unload Proof)

• Confirm that the Drum Motor is in position to peel the Proofing Media from the drum.
  If the Drum Motor is not in the correct position for the Receiver or Donor:
  • Receiver: Change the Drum Motor Position Ready to Peel Receiver parameter from the default of -28 to a value between -24 - -26.
  • Donor: Change the Drum Motor Position Ready to Peel Donor parameter from the default of -15 to a value between -8 - -10. For the Donor, the Proof Unloading Bar suction cups must catch the Donor from its edge (see Figure 4).
    

  
  Figure 4: Unload Suction Cups at the Edge of the Donor