HP Latex 1500 User guide - Page 386

compensate for the contraction of the substrate. Alternatively, change to a less thermal-dependent substrate to reduce the contraction. How to achieve better consistency between jobs of the same length The printer has been designed to maximize consistency in the length of the printed substrate. However, there are external variables that can contribute to variability: substrate variations and enviromental conditions. 1. Select a substrate which is less susceptible to expansion when being printed on. Most paper-based substrates have a tendency to expand. ● If you need to print on a substrate susceptible to expansion: - Ensure that the density of ink is similar between each tile (if not, the tile with less ink might be shorter). - If possible, decrease the heating temperature. - Reduce the ink restrictions as much as possible. ● Make sure that the roll is left within the room where the printer is located for at least 24 hours, this is to ensure the complete roll has the same temperature as the printer. 2. Do not touch the print adjustments (no change of substrate advance compensation) between tiles. 3. Print all the tiles at once. ● Do not split the jobs at different times (1 tile one day, and the 2nd tile the 2nd day) ● Do not change the print mode or the substrate width between tiles. The objective is to make sure that there is no pause between the tiles. When using the Queue mode in the Internal Print Server, there is still a small time between jobs, which could add more variability between the lengths of the tiles.To print the tiles all at once, we recommend the following: a. Create the tiles from the Internal Print Server. b. If you are creating the tiles from the RIP, ensure that you send all the tiles within the same jobs sent to the printer/Internal Print Server. 4. In order to make sure that even the first tile has less difference in length compared with the other ones, add a top margin of 50 cm. In case you have to reprint one tile, in order to ensure the length will be as close as the previous jobs: ● Make sure that the substrate and also the ambient temperature of the printer are the same as when the previous job was printed. ● Add a top margin of 50 cm. ▲ But in any case, when having to reprint a tile later, there is a higher probability that the length will be different from the other tile length. The total length repeatability depends on the substrate, the changes in environmental conditions, and the contents of each job (mainly when the substrate is reacting differently depending on the ink density). The collector stops winding The collector has a safety timer that will stop rewinding substrate if it is not fully collected after 30 seconds, and will stop unwinding substrate after 5 seconds if the substrate loop is not detected by the collector sensor. If you 378 Chapter 12 Troubleshoot substrate issues ENWW