Chapter 22-26F-2-402.3.6.6 Checking the Life of the Drum Cartridge 0008-1715a. OutlineThe machine uses the following mechanism to check the life of the drum cartridge.When the power is turned on, the upper cover is closed, or a print job is over, the DCNT Board checks on the following 2 items, and will assume that the cartridgehas reached the end of its life if any of them reaches a specific value:- life of photosensitive drum (hours of use)- amount of waste tonerThe life of the drum cartridge is indicated to the SCNT Board in 2 steps (warning, end of life); the printer engine is stopped only when the end of life has beenidentified.The following mechanisms are used to detect the end of life of the photosensitive drum and the level of waste toner:b. End of Life of the Photosensitive DrumThe end of life of the photosensitive drum is checked by the DCNT Board by monitoring how long the photosensitive drum has been used with reference to the datastored in the memory tag. The memory tag retains data on the period during which the photosensitive drum has been used (i.e., length of primary AC application +number of drum rotations) sent by the DCNT Board.The DCNT Board updates the data each tine the power is turned on, the upper cover is closed, or a print job is over; when the cumulative period of use reaches aspecific level, it will identify the condition as indicating the need of replacement of the drum cartridge.c. Waste TonerThe machine is equipped with a mechanism to find out when the cartridge becomes full of waste toner. The detection is undertaken by the DCNT Board by moni-toring the output of the waste toner detection mechanism, which consists of a light-emitting member (LED) and a light-receiving member (PD) as well as a PCB.The DCNT Board causes the LED to emit light using the LED drive signal (P3.3V); the light from the light-emitting member reaches the cartridge along the lightguide mounted to the cartridge. The light them moves through the cartridge, and is detected by the light-receiving member after passing along the light guide; theresult is then sent to the DCNT Board in the form of the waste toner detection signal (WASTONS).The DCNT Board checks the level of waste toner with reference to the cumulative period of WASTONS for each single rotation of the stirring plate inside thecartridge when the power is turned on, the upper cover is closed, or a print job is over, and will assume that the cartridge is full of waste toner if it finds that thelevel has reached a specific value.DCNT BoardITB home positionsensor (PS71)Interrupting areasDrum cartridgeInterrupting areasSCNT BoardTOPSNSSecondarytransfer rollerTR2SH.V.T
