A magnetic drum includes: a fixed magnetic drum, fixedly installed on a card holder; a rotating magnetic drum, rotatably installed coaxially with the fixed magnetic drum, and having several magnetic heads; first The converter is installed on the rotating drum and is electrically connected to the magnetic head, and is used to send and receive electrical signals to/from the magnetic head; the second converter is installed on the fixed drum opposite to the first converter, and is used to send and receive electrical signals to/from the magnetic head. Receive electrical signals without contacting the first converter; several channels are independently wound on the second converter and constitute a signal transmission path; a short-circuit ring is wound between the channels of the second converter to prevent signal crossovers; and wires electrically connected to several channels and having a ground wire connected to a short-circuit ring for grounding.
Laser printer toner cartridges can be divided into three categories according to different combination methods: integrated toner cartridges, two-body toner cartridges and three-body toner cartridges. The integrated toner cartridge is a toner cartridge in which the photoconductor drum (photosensitive drum), magnetic drum (developing roller) and toner cartridge are integrated into one. In principle, the design structure of this toner cartridge does not allow users to add toner. Two-body toner cartridge means that the toner cartridge is divided into two parts, one part is the photoconductor drum, and the other part is the magnetic drum and toner cartridge. After the user uses up the toner, he only needs to replace the magnetic drum and toner cartridge components instead of the photoconductor drum. . The three-body toner cartridge means that the toner cartridge is divided into three independent parts: the photoconductor drum, the magnetic drum, and the toner cartridge. After the user uses up the toner, he only needs to replace the toner cartridge, which is what everyone usually calls toner separation technology. For two-body and three-body toner cartridges, the photoconductor drum also has a certain service life.