Abstract: A transformer 6 and a photocoupler 5 are provided to ensure insulation between a primary side circuit section 10 connected to an alternating current power supply 2, and a secondary side circuit section 20 for applying a voltage to a lamp 4. A detection circuit section 22E, provided in the secondary side circuit section 20, detects an output voltage and an output current of the lamp 4 to detect a deviation from a predetermined power. A signal corresponding to the deviation, which has been detected by the detection circuit section 22E, is transmitted to the primary side circuit section 10 via the photocoupler 5 provided between the primary side circuit section 10 and the secondary side circuit section 20. A switching control section 13, provided in the primary side circuit section 10, carries out switching control for constant power lighting based on the signal transmitted from the photocoupler 5.

Abstract: A transformer 6 and a photocoupler 5 are provided to ensure insulation between a primary side circuit section 10 connected to an alternating current power supply 2, and a secondary side circuit section 20 for applying a voltage to a lamp 4. A detection circuit section 22E, provided in the secondary side circuit section 20, detects an output voltage and an output current of the lamp 4 to detect a deviation from a predetermined power. A signal corresponding to the deviation, which has been detected by the detection circuit section 22E, is transmitted to the primary side circuit section 10 via the photocoupler 5 provided between the primary side circuit section 10 and the secondary side circuit section 20. A switching control section 13, provided in the primary side circuit section 10, carries out switching control for constant power lighting based on the signal transmitted from the photocoupler 5.

Abstract: The present invention provides an electrophotosensitive material comprising a photosensitive layer containing a m-phenylenediamine compound represented by the general formula (1): ##STR1## wherein R.sup.1A and R.sup.1B are the same or different and indicate an alkyl group; and R.sup.1C, R.sup.1D, R.sup.1E and R.sup.1F are the same or different and indicate a hydrogen atom or an alkyl group, which has high sensitivity and issuperior in stability to strong light, durability and heat resistance, and an image forming method capable of realizing more higher speed and more larger energy saving than the prior art.

Abstract: The present invention provides a novel tryptanthrine derivative represented by a general formula: ##STR1## wherein R.sup.1 is an oxygen atom, or group represented by a formula: ##STR2## wherein R.sup.2A and R.sup.2B are the same or different and indicate a hydrogen atom, a cyano group, an acyl group, an alkoxycarbonyl group or an alkyl group, provided that R.sup.2A and R.sup.2B are not hydrogen atoms simultaneously; andR.sup.3A, R.sup.3B, R.sup.3C, R.sup.3D, R.sup.4A, R.sup.4B, R.sup.4C and R.sup.4D are the same or different and indicate a hydrogen atom or an alkyl group which may have a substituent, provided that when R.sup.1 is an oxygen atom, any one of R.sup.3A through R.sup.4D is a cyano group.Such a tryptanthrine derivative has an excellent electron transport capability to be suitably used for the electrophotosensitive material.