Product

Operating system

Windows 95

Background

The official throughput of the Lotem 800 Quantum, under controlled conditions, is 25 plates/hr. Due to the system's fast data transfer, exposure time is very short. The loading cycle significantly influences throughput (a lengthy loading cycle produces fewer plates/hr).
Note: A maximum of 25 plates/hr applies only to V-speed calibrated machines.

The throughput is measured at 2400 dpi. However, if it is a 2540 dpi head, approximately one plate less per hour will be produced. Make sure you use the proper parameters (wpower and drum speed).

Procedure

To achieve optimum throughput:

1. Ensure that the plate has a sensitivity of 130 mj/cm2 or lower (currently applicable to Agfa P970 and Mitsubishi LT-2). A less sensitive plate produces a drum speed slower than the maximum speed (375 rpm), and lengthens exposure time.
   The official way to determine plate and drum speed is via the Media Spec Datasheet. Select the correct plate name, CTP device and Head dpi, and enter the default plate size: 1030 (40.5").
2. On V model machines, check that you are running with two TSP boards defined at the Brisque.
3. Measure throughput with a 1030 mm (40.5") plate. A longer plate requires longer exposure time; however, a shorter plate does not always boost the speed even though exposure is faster, as the loading cycle does not have sufficient time to bring the plate to the drum.
4. Use only two working punch units per plate. Each additional punch adds 4-7 seconds to the loading cycle and may reduce speed.
5. When working with the MCU configuration, measure the speed without changing cassettes (each change requires approximately 2.5 minutes).
6. Special settings in the loading cycle may slow productivity. Each plate size has a Fast and Slow loading option. To set the loading option, change to Expert mode, click the Advance setting in the Media Definition window, then verify the following:

• Fast mode is selected (uses a faster X/Y motor speed and cycle is shorter). Drum speed is always a fast speed.
• The plate backward separation number (under Loading system/Load plate from Cassette) is set properly. If the number is too high (for example, 3-4), the cycle is four seconds longer per backward movement.
• The GTO plate support rollers may slow down the loading cycle (performing throughput on GTO plates is not recommended).
• The special punch configuration (variable edge or pitch) also increases cycle length. Use a standard punch only.

7. Measure throughput by the time interval between the first and second plates exiting the Lotem.
8. Ensure that the same plate size is used.
9. Ensure that the head works with 224 pixels. Chopped pixels will reduce the machine's throughput.
10. Stop spirals occurring at the Brisque/Splot (retrace on the Quantum). This indicates a bottleneck at the front end.
11. The Verbose option is disabled. If it slows down the system after being enabled, disable it according to the instructions in: 5320 buffer overflow on the Lotem Quantum.

Technical contact(s)

Nir Peleg

Date submitted

18 Dec 2002