Sharp Kabushiki Kaisha Corporation

Takasumi Wada

Yasuhiro Ono

Hirokazu Fujita

Nobuhiro Shirai

Kenzo Ohkubo

Yoichi Yamamoto

Kouichi Irihara

Kenji Tani

Takayuki Ohno

Keiji Taniguchi

Atsushi Ueda

Masahiko Aiba

Katsumi Adachi

Fumio Shimazu

Takashi Hayakawa

Kimihide Tsukamoto

Ayumu Oda

Tetsushi Ito

Tomohiro Oikawa

Yukihito Nishio

Daisaku Imaizumi

Makoto Masuda

Hideo Yamasa

Takahisa Narikiyo

Manabu Matsuo

Koichi Inui

Koji Tsukamoto

There are provided a light-emitting device, an illuminating apparatus, and a display apparatus in which, in order to apply light to an object to be illuminated with uniformity in light intensity, the quantity of light which is applied to a part of an edge of a to-be-illuminated region of the to-be-illuminated object located near a light-emitting section can be lessened. A backlight unit includes a printed substrate, a plurality of light-emitting sections each of which has a base support, an LED chip and a lens, and reflective members each of which is placed around the light-emitting section and has a first wall portion and a second wall portion.

Light emitting device, illuminating apparatus, and display apparatus

An optical scanning device includes an enclosure having a plurality of windows covered with transparent members. The enclosure houses a plurality of light sources, a scanning portion, optical elements and a light amount attenuation portion. The scanning portion deflects each of a plurality of light beams emitted from a plurality of light sources at a constant angular speed in a main scanning direction. The optical elements constitute respective light paths from the scanning portion to the windows for the plurality of light beams, respectively. The light amount attenuation portion attenuates light amount in a light path of a first light source among the plurality of light sources in a downstream side of the position where a light beam emitted from a second light source enters as stray light. The drive portion drives the first light source so as to compensate for light amount attenuated by the light amount attenuation portion.

Optical scanning device and image forming apparatus

An optical scanning device cover, covering an upper portion of an optical scanning device, includes an exposure window, a close stopper, an open stopper, and a rotation cam plate. A projection to be held in a link portion of a rotation cam is fixedly provided on a shutter. When the rotation cam is rotated in a direction of an arrow R() from a state in which the shutter is closed, A-side of the shutter turns until the shutter comes into contact with the open stopper to open that side of shutter, and thereafter, the B-side of the shutter turns to open that side of the shutter.

Optical scanning device and image forming apparatus provided with the same

An optical scanning unit irradiates a polygon mirror with a plurality of light beams emitted from a light source according to image data, and scans and exposes a plurality of photoreceptors with the plurality of light beams as scanning lights. The optical scanning unit comprises a primary optical system unit including an optical system that emits the plurality of light beams, which are emitted from the light source toward the polygon mirror, and a secondary optical system unit including an optical system that emits the light beams, which are reflected by the polygon mirror toward the photoreceptors. The arrangement is such that the primary optical system unit is fitted removably to the secondary optical system unit, and that a combined unit of the primary optical system unit and the secondary optical system unit is removably fitted to an image forming apparatus having the photoreceptors.

Optical scanning unit and image forming apparatus

A laser scanning optical system converts a plurality of beams emitted from the laser diode (LD) into parallel light using a collimator lens, shapes the parallel light using an aperture, and executes exposure of a plurality of lines simultaneously on a photoreceptor drum. To cause a necessary emitting point interval d determined uniquely from the magnification of the optical system to coincide with an emitting point interval of the LD used, the LD is rotated by an angle &#x3b8; against the main optical axis plane thereof. In this case, a converting device that converts the aspect ratio of a profile of the light beam emitted from the LD is provided. A conversion characteristic of the converting device is adjusted such that the characteristic is matched with a condition within a predetermined region following a characteristic of the optical system.

Laser scanning optical system and image forming apparatus

In an exposure unit including: a laser scanning unit emitting a multiple number of beams; a polygon mirror for deflecting the multiple beams by reflection with the same facet; an optical system including optical elements for leading the beams correspondingly to a multiple number of photoreceptor drums laid out along an auxiliary scan direction, the bottom of a casing of the exposure unit to which the polygon mirror and the optical elements arranged along the directions of the beams emitted from the polygon mirror are attached is constructed so that the attachment portions of individual optical elements for each beam are differentiated in thickness from the areas where no attachment portion is formed.

Light scanning device and image forming apparatus using the same

A capacitive load driving circuit () for charging and discharging a capacitive load () is provided with a voltage divider () for dividing a power supply voltage (VH) into a plurality of different voltages (V&#x2013;V), a plurality of condensers () to which the voltages (V&#x2013;V) are respectively charged as terminal voltages, and a switch () for switching connections between the capacitive load () and the condensers (), the switch () sequentially connecting the condensers () in an ascending order of the terminal voltages so that electrostatic energy is supplied to the capacitive load () when the capacitive load () is charged, the switch () sequentially connecting the condensers () in a descending order of the terminal voltages so that electrostatic energy is collected from the capacitive load () when the capacitive load () is discharged. With this, it is possible to provide a capacitive load drive circuit having a simple circuit configuration and capable of efficiently collecting and reusing energy accumulated in the capacitive load, and a capacitive load driving method.

Capacitive load driving circuit, capacitive load driving method, and apparatus using the same

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&lE;1.5 kV and EH&gE;1.8 kV/mm, respectively. Thus it is possible to provide a toner jet image forming device which reduces scattering occurring when the toner particles strike the transfer material, and which is able to form good pixels and good images.

Image forming device

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. As a result, the measuring device for amount of charge of developer can be obtained at low cost.

Measuring device for amount of charge of developer

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.

Image forming apparatus

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. This structure prevents adhesion of the toner to the control electrode, thereby obtaining a quality image.

Color image forming apparatus by direct printing method with flying toner

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.

Image forming device having control grid with applied voltage of the

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. The second exposing unit forms a second electrostatic latent image by interlocking or synchronizing with the developing operation of the developer unit. This makes it possible to easily form a synthetic image at a high speed by superimposing characters printed by a printer function onto a copy image formed by a copying function, for example.

Copying machine with image superposition capability

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. The measuring device for an amount of charge of toner becomes compact, so it can be installed in an image forming apparatus.

Measuring device for amount of charge of toner and image forming

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. According to the electrophotographic printing machine, the image forming process will not be continued with the detective portion on the photosensitive layer. Thus, the contact charger can be prevented from breaking down.

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Nara, Japan

Takasumi Wada