Patent ID: 8509638

Claim:
A system for continuous and simultaneous regulation of real values of toner concentration and fill level in a mixing unit to predetermined desired values in a developer station of an electrographic printing apparatus, said mixing unit having at least toner and carrier fluid, comprising: a first reservoir for a toner concentrate having at least said toner and said carrier fluid, said first reservoir being connected via a first control element with a mixing unit; a second reservoir for said carrier fluid, said second reservoir being connected via a second control element with the mixing unit; a first control unit with a first regulator that regulates the first control element such that said real value of said toner concentration in the mixing unit is adjusted by supplying said toner concentrate from the first reservoir, the first regulator regulating the first control element depending on a desired concentrate value determined from the predetermined desired values of the toner concentration and fill level and depending on a real concentrate value determined from the real values of the toner concentration and the fill level measured in the mixing unit; and a second control unit with a second regulator that regulates the second control element such that said real value of said fill level in the mixing unit is adjusted by supplying said carrier fluid from the second reservoir, the second regulator regulating the second control element depending on a desired carrier fluid value determined from the predetermined desired values of the toner concentration and the fill level and depending on a real carrier fluid value determined from the real values of the toner concentration and the fill level measured in the mixing unit.