Abstract: A nonvolatile semiconductor memory of an aspect of the present invention comprises a voltage step-down circuit including a first and a second circuit to achieve a voltage drop and configured to decrease the first voltage to a second voltage less than the first voltage, a transfer transistor to transfer the second voltage to a word line, and a control circuit to generate the second voltage as a first write voltage in a first mode wherein the first write voltage less than or equal to a prescribed magnitude is applied to the word line, and to generate the second voltage as a second write voltage in a second mode wherein the second write voltage greater than the prescribed magnitude is applied to the word line, wherein the difference between the first voltage and the second voltage is greater than or equal to the threshold voltage of the transfer transistor.

Abstract: A power supply circuit has a control circuit. The control circuit outputs a control clock signal so as to cause a first booster circuit to compulsorily perform boosting operation with a first boosting capability in response to an output signal of a second comparison amplifier after a lapse of a prescribed period since the first booster circuit is started to perform boosting operation with the first boosting capability in response to a first activation signal of a first comparison amplifier.

Abstract: A memory includes first selective transistors connected between one end of cell strings and bit lines; second selective transistors connected between the other end of the cell strings and a cell source line; a dummy cell string; a first dummy selective transistor connected between one end of the dummy cell string and a dummy bit line and whose gate is connected to a first selective gate line; a second dummy selective transistor connected between the other end of the dummy cell string and the cell source line and whose gate is connected to a second selective gate line, wherein at a time of writing in a selected memory cell, a voltage of a first dummy bit line selected is driven to a different voltage from a voltage of an unselected bit line, and any of the dummy cell transistors connected to the first dummy bit line is written.

Abstract: A powder stirring device which has a simple structure and can effectively stir toner. A stirring pin in a reserve tank has a middle space and includes pin elements. When the stirring pin rotates, toner in the reserve tank is stirred by the pin elements. The toner is diffused through the middle space between the pin elements and is sufficiently mixed with air, thus becoming powdery. The stirred powder-type toner is spread in the reserve tank and is provided to a development unit.

Abstract: A toner cartridge is detachably loaded in a predetermined loading portion of an electrophotographic apparatus and has a new toner containing space where new toner is contained, and a waste toner containing space where waste toner is contained. The toner cartridge includes a main body, a supply hole supplying the new toner and a receiving hole for receiving waste toner, which are installed at a predetermined position of the main body of the toner cartridge, and an open and shut mechanism having a single shutter opening and shutting the supply hole and the receiving hole. The electrophotographic apparatus for forming an image on a recording medium includes the loading portion where the toner cartridge is detachably installed, and the toner cartridge.

Abstract: A powder stirring device which has a simple structure and can effectively stir toner. A stirring pin in a reserve tank has a middle space and includes pin elements. When the stirring pin rotates, toner in the reserve tank is stirred by the pin elements. The toner is diffused through the middle space between the pin elements and is sufficiently mixed with air, thus becoming powdery. The stirred powder-type toner is spread in the reserve tank and is provided to a development unit.

Abstract: A toner cartridge which is detachably loaded in a predetermined loading portion and has a new toner containing space where new toner is contained and a waste toner containing space where waste toner is contained, the toner cartridge including a supply hole for supplying new toner and a receiving hole for receiving waste toner, which are installed at a predetermined position of a main body of the toner cartridge, and an open and shut mechanism for opening and shutting the supply hole and the receiving hole by a single shutter. An electrophotographic apparatus for forming an image on a recording medium by adhering toner to a photoreceptive body where an electrostatic latent image is formed and transferring the toner to the recording medium from the photoreceptive body, in which the electrophotographic apparatus includes a loading portion where the toner cartridge is detachably installed the toner cartridge.