HP 1320 Service Manual - Page 195

Half self-test functional check The print process can be subdivided into the following stages: ● image formation stage (charges the drum and writes a latent image to the drum with the laser) ● development stage (forms a toner image on the drum) ● transfer stage (transfers the image to paper) ● cleaning stage (removes excess toner from the drum) ● fusing stage (applies heat and pressure to make the image on paper permanent) To perform a half self-test check The purpose of the half self-test check is to determine which process is malfunctioning. 1. Print a configuration page. 2. Open the print cartridge access door after the paper advances halfway through the printer (approximately five seconds after the motor begins rotating). The leading edge of the paper should have advanced past the print cartridge. 3. Remove the print cartridge. 4. Open the print cartridge drum shield to view the drum surface. If a dark and distinct toner image is present on the drum surface, assume that the first two functions of the electrophotographic process are functioning (image formation and development). Troubleshoot the failure as a transfer or fusing problem. To perform other checks If there is no image on the photosensitive drum, perform these checks: 1. Make sure you removed the entire length of the sealing tape from the print cartridge before you installed the cartridge. 2. Perform a drum rotation functional check to ensure that the drum is rotating (see Drum rotation functional check ). 3. Perform a high-voltage power-supply check. (See below.) ENWW Functional checks 183