| 摘要 |
PURPOSE:To adjust variance in operation density due to variance of the manufacture of a differential transformer easily and securely by adding part of the driving voltage of a driving coil to a differential output. CONSTITUTION:The differential transformer 2 is equipped with the driving coil N1 which is driven by an AC driving source 1, a detection coil N21 whose output voltage E1 varies with toner density, and a reference coil N22 which is not influenced by the toner density. The driving voltage Vin is divided by a resistance voltage dividing circuit VR and added to the differential output E0 between the output voltage E1 of the detection coil N21 and the output voltage E2 of the refernce coil N22 at one terminal side of the reference coil N22, so that E0=E2-E1+Vin1. This output is inputted to a signal processing circuit 3 and a phase or voltage discriminating means detects the toner density. |
