The Gestetner 7528N is copier ideal for medium and large size tasks. The average speed of the copier is 32 ppm black / 28 ppm color. The Gestetner 7528N uses black cartridge number 888442 , cyan cartridge number 888445, magenta cartridge number 888444 , and yellow cartridge number 888443 with an average page yield of 24,000 pages for black and 10,000 pages for the colors at a 5% coverage, which is usually a regular letter size page with text. The standard paper capacity is 1,100 sheets. The copy resolution is 600 x 600 dpi. The replacement cycles of the printer are convenient, mostly based on the high yield capacity of the cartridges that reduces the cost per page, and allows users to utilize the color features of the printer without fear of breaking the bank.
Open the cover board on the right side of the printer.
Press the slide of the cartridge, and push it back to the limit. 
Open it from outside and take out the used cartridge. 
Take the new cartridge out of the box and shake it firmly.
Put the cartridge into the printer.
Pull the cartridge forward, press the lock to put it on place and close the cover board