Dolev 4press - Troubleshooting & Diagnostics
Workflow System

Exposure Steps
Exposure Sequence
Unload to Acc. Cassette
Stretch
Prepare Film Feed
Film Loose / Relief
First Load
End of Film (to cassette)
Cut
Attach

Start up Flow Chart (memo)

Exposure Steps

Film plotting is performed in a set sequence, during which time standard status messages are displayed on the control monitor. These status messages keep the Operator informed as to the exact state of the process, and can be used to isolate exposure problems.

Load Exposure Parameters	Exposure format data for the current file is sent from the Host and loaded into memory. Spinner revolution is set to its exposure speed.
HP Calibration	The carriage is set to the Home Position (HP), the zero reference point prior to plotting.
Light Calibration	The laser is set to the appropriate intensity, as specified in the exposure format parameters sent from the Host.
Start Exposure	The Stepper begins operation. Rasterized file data is sent from the Host to the VLSI, where it is processed. The resulting processed data is sent via the HOMC to the LDR, which controls laser light operation. The subsequent laser beam pulses are transmitted via fiber optics cable to the Pentaprism and onto the film.
End of Plot (EOP)	An End of Plot signal is sent from the Host and is verified by the Imagesetter. Spinner rotation is lowered to its idle speed.
Advance	Moves the film along film path toward the accumulating cassette or the inline processor.Though actually part of the Film Loading and Unloading process, the Advance step is also integral to the exposure process described here.
Carriage to HP	The Dynamic Optics Carriage is returned to the Home Position.

Exposure Sequence

The Imagesetter is in Standby mode. The Host sends exposure format data for the current file and issues a command to start exposure.
Load Exposure Parameters is performed. Critical exposure parameters (e.g., laser intensity, spinner speed and file size) are received by the Imagesetter. When all parameters have been received, the Spinner speed is adjusted to the required rate of revolution.
Note: By default, the Spinner remains in motion between exposures.
When necessary, an Advance is performed to position new film in the Imagesetter drum. During this step, the Dynamic Optics Carriage is moved the center of the drum.
An HP Calibration is performed and the Dynamic Optics Carriage is set to its Home Position.
The Imagesetter performs a laser Light Calibration. This operation sets the laser light to the intensity specified in the exposure format sent from the Host.
Calibration is achieved by sending a calibration laser beam to the Pentaprism located inside the Dynamic Optics Assembly. During this process the transmitted beam is directed to the Light Detector located beneath the Spinner. An intensity reading is taken and is returned to the HOMC board, which issues an adjustment command to the Laser Driver in the Static Optics Assembly. Intensity adjustments are made via the ND Filter. When the laser light has been adjusted to the correct intensity, the calibration process stops.
Start Exposure is performed. A data handshake is first established. During communication, job progress is constantly compared between the Host and the Imagesetter based on the file size parameter.

Following the handshake, rasterized file data begins to stream from the Host to the VLSI board, where processing is performed. VLSI processed data is sent via the HOMC to the Laser Driver, which translates the information into on/off instructions for the laser. Light emitted from the laser is then transmitted via fiber optics cable directly to the Pentaprism, which is spinning inside the Dynamic Optics Carriage.

The Stepper—which has been inactive—begins to operate. The Stepper Driver monitors the Spinner revolution index sent by the Spinner encoder and moves the Dynamic Optics Carriage along the length of the Lead Screw according to this count. Monitoring and motion continue throughout the exposure.

The combined spinning of the Pentaprism and stepping movement of the Dynamic Optics Carriage inside the Imagesetter drum produce the precise coordinates necessary for laser light exposure on the film.

Rasterized data continues to stream from the Host to the Imagesetter until the end of the rasterized data file is reached.

When the rasterized data stream from the Host ends, an End of Plot (EOP) is performed.
If the last exposure has been made for the current piece of film, the following actions are taken:
- Spinner revolution is reduced to its non-exposure speed.
- If a punch system is configured in the Imagesetter, a Punch is performed.
- A Carriage to HP is performed, returning the Dynamic Optics Carriage to the Home Position.
- Optionally, a Cut and Collect is performed.