Abstract: A capacitive load driving circuit (1) for charging and discharging a capacitive load (11) is provided with a voltage divider (5) for dividing a power supply voltage (VH) into a plurality of different voltages (V1–V9), a plurality of condensers (2a–i) to which the voltages (V1–V9) are respectively charged as terminal voltages, and a switch (7) for switching connections between the capacitive load (11) and the condensers (2a–i), the switch (7) sequentially connecting the condensers (2a–i) in an ascending order of the terminal voltages so that electrostatic energy is supplied to the capacitive load (11) when the capacitive load (11) is charged, the switch (7) sequentially connecting the condensers (2a–i) in a descending order of the terminal voltages so that electrostatic energy is collected from the capacitive load (11) when the capacitive load (11) is discharged.

Abstract: A capacitive load driving circuit (1) for charging and discharging a capacitive load (11) is provided with a voltage divider (5) for dividing a power supply voltage (VH) into a plurality of different voltages (V1-V9), a plurality of condensers (2a-i) to which the voltages (V1-V9) are respectively charged as terminal voltages, and a switch (7) for switching connections between the capacitive load (11) and the condensers (2a-i), the switch (7) sequentially connecting the condensers (2a-i) in an ascending order of the terminal voltages so that electrostatic energy is supplied to the capacitive load (11) when the capacitive load (11) is charged, the switch (7) sequentially connecting the condensers (2a-i) in a descending order of the terminal voltages so that electrostatic energy is collected from the capacitive load (11) when the capacitive load (11) is discharged.

Abstract: The present image forming device is provided with a toner carrier and a counter electrode opposite the toner carrier. Between the toner carrier and the counter electrode is provided a jet control section having a plurality of gates, each forming a space for passage of a jet of toner. Also provided is a control electrode driver, which is capable of applying potentials independently to each gate of the jet control section. The present image forming device forms a toner image on a transfer material by controlling passage of toner through a given gate by application of an ON potential which allows passage of the toner through the gate and an OFF potential which prevents passage of the toner through the gate. A potential difference VH between the toner carrier and the counter electrode and an intensity EH of an electrical field in the vicinity of the counter electrode satisfy VH≦1.5 kV and EH≧1.8 kV/mm, respectively.

Abstract: An apparatus for printing directly on plain paper, utilizing an arrayed control grid having a plurality of toner slots disposed in a space between a toner carrier and a backing electrode on which a paper travels. The backing electrode formed in a flat plate facing paralleledly to the control grid assures a uniform electrostatic field in an interspace therebetween. A unit body associated with the toner carrier and the control grid makes the interspace open when the unit body is removed from the apparatus body which offers an easy access to the interspace and the members as well. A resiliently suspended backing electrode with a spacer, a restriction member etc., assures the interspace constant. Other unit bodies including the control grid associated with the backing electrode and others are also disclosed.

Abstract: A measuring device for amount of charge of developer includes an upper electrode, a lower electrode provided under the upper electrode, which are provided in parallel so as to face each other, flying electric field voltage application unit for applying a flying electric field voltage to the upper electrode, for generating an electric field so as to fly developer from the lower electrode to the upper electrode, current detection unit for detecting a current flowing in the upper electrode, and arithmetic unit for computing a total amount of charge of the developer adhering to the upper electrode based on a change in amount of current detected by the current detection unit, wherein a current that generates as a toner T adheres to the upper electrode is detected by the current detection unit, and based on a change in amount of the current, a total amount of charge of the developer adhering to the upper electrode is computed by the arithmetic unit.

Abstract: An image forming apparatus has a toner carrier roller, a back electrode which is located so as to face the toner carrier roller, a voltage source for applying a voltage which generates an electric field for making toner fly from the toner carrier roller to the back electrode, a control electrode which has many openings through which the toner is allowed to pass and first and second conductive layers formed around the openings and is formed so that at least portions of the first and second conductive layers which surround the openings do not overlap each other in a direction where the toner flies from the toner carrier roller to the back electrode, and a voltage source for applying a voltage which controls the toner passing through the opening according to an image signal. As a result, an electrostatic capacity is hardly formed between the first conductive layer and the second conductive layer, thereby suppressing a fall in response characteristic to the toner flying control due to the electrostatic capacity.

Abstract: A color image forming apparatus includes development rollers, aligned in the transport direction of recording paper, for carrying toner of respective colors charged in a predetermined polarity. A driver substrate having a plurality of toner passing holes in locations facing the development rollers is installed. Control electrodes are mounted around the toner passing holes. A back electrode is mounted opposite to the driver substrate so that the recording paper passes through a section between the back electrode and the driver substrate. A voltage whose polarity is opposite to the toner is applied to the back electrode, while either a first voltage or a second voltage is selectively applied to the control electrode according to an image signal. The first voltage allows the passage of toner through the toner passing holes. The second voltage prevents the passage of the toner. Both the first and second voltages to be applied to the control electrode have the same polarity as the toner.

Abstract: In the invention, toner on a toner carrier is charged with negative polarity and attracted by applying positive voltage to a backing electrode placed at the back of a transfer belt. Voltage is applied across the electrodes arranged crosswise in directions X and Y of the control grid disposed between the transfer belt and the toner is changed so as to vary the toner repulsing force in space-charged opening XY of the control grid and thereby to regulate the amount of toner passing therethrough.

Abstract: An image forming apparatus includes a charging roller for charging a surface of a photoconductive layer in a photoreceptor so as to have a prescribed polarity, a first exposing unit which is arranged on a downstream side of the charging roller on the basis of a direction in which the photoreceptor moves, a developer unit which is placed on a downstream side of the first exposing unit and which keeps toner, to which a charge with a polarity opposite to the prescribed polarity is applied, in contact with a photoconductive layer, and a second exposing unit for directing light generated according to an image signal to a back of the photoconductive layer at a contact position of the toner and the photoconductive layer. The first exposing unit directing light reflected from a document to which a light is applied to the surface of photoconductive layer so as to form a first electrostatic latent image.

Abstract: A measuring device for an amount of charge of toner including countered first and second electrodes for forming an electric field which accelerates toner particles, a voltage generator for applying a voltage across the first and second electrodes, a magnifying optical system for magnifying the image of toner particles which move between the first and the second electrodes, a light source for illuminating a vicinity of a focus of the magnifying optical system, a CCD sensor for receiving an optical image of the toner particles magnified by the magnifying optical system so as to convert the optical image into an image signal and a CPU for controlling a voltage from the voltage generator based upon the image signal so that the toner particles pass a prescribed position in the vicinity of the focus of the magnifying optical system and for obtaining an amount of charge of toner particles from a value of the voltage, and an image forming apparatus in which the measuring device is installed.

Abstract: An electrophotographic printing machine is provided with a photoreceptor drum including a photosensitive layer formed on a surface of an electrically conductive base, a contact charger in contact with the photosensitive layer for charging the photosensitive layer by applying thereto a DC voltage, and a voltage drop detecting circuit for outputting a detecting signal when the voltage has dropped below a reference voltage. When a defect exists such as a pin hole on the photosensitive layer, the voltage being applied to the photosensitive layer of the contact charger drops. In this state, a detecting signal is output to a controller from the voltage drop detecting circuit. When the controller receives the detecting signal, the controller signals to stop the operation of the entire device, and signals a display to display a message indicating to exchange the photoreceptor drum.

Abstract: The invention is directed to an apparatus for an electrophotographic process, equipped with a charging device of a contact type using a conductive roller or brush, and the charging device used therefor.

Abstract: An apparatus and method for printing directly on plain paper, utilizing an arrayed control grid having a plurality of toner slots. An alternating electrostatic field in a space between a toner carrier and a backing electrode gives toner a vibrational motion to prevent a toner clog at the slot. The field is also formed to repel the clogged toner back to the toner carrier, or to fall it down on a paper on the backing electrode during no print is performed to clean the control grid. A constitution of conductive and dielectric materials for the members assures to form the field.

Abstract: An electrophotographic printing machine is provided with a photoreceptor drum including a transparent cylindrical base having a transparent electrically conductive layer and a photoconductive layer laminated in this order on a surface thereof and a dielectric belt in contact with the photoconductive layer. The photosensitive layer is exposed while voltage is being applied across an electrically conductive toner and a transparent electrically conductive layer, thereby forming a toner image on the photosensitive layer. After the toner image on the photosensitive layer is transferred to the dielectric belt which temporarily carries the toner image, the copying material is superimposed on the toner image, and heat and pressure are applied to the toner image respectively from a heater and a pressurizing roller.

Abstract: The invention relates to a method and apparatus for forming a toner layer adapted for electrophotographic developing apparatuses for developing using magnetic toner. Toner carried on a toner carrier and flowing toward the developing position is regulated in thickness by a toner layer thickness regulating member contacting the surface of the toner carrier. Lines of magnetic force are applied to the toner layer having a regulated thickness so as to stir the toner conveyed toward the developing position, thereby forming a uniform toner layer at the downstream side. The toner layer thickness regulating member can be a thin plate member of a nonmagnetic material having elasticity, or a rigid blade having a pivotal proximal end. The toner is stirred in a repulsive magnetic field forming region formed between a magnetic blade and the toner carrier.