Oki Data Corporation

Kenichi Ashida

Norio Nakajima

Hiroaki Sato

Koji Ida

Kimihide Ishizaki

An image-writing device writes a dot image onto an image-receiving body in such a way that the dots align at a certain screen angle. The dots are written by an array of writing elements such as light-emitting diodes. The image-writing device has a memory that stores compensation parameters that compensate for non-uniformity of the writing elements. The compensation parameters are also calculated to produce dots with approximately uniform widths as viewed in the screen-angle direction. When driven according to the compensation parameters, the writing elements produce a dot image that is comparatively free of dot-width irregularities aligned in the screen-angle direction, which is the direction in which such irregularities are most noticeable.

Image-writing device and method and image-forming apparatus reducing dot width variations in relation to a screen angle

An electrophotographic image forming apparatus in which an electrostatic latent image is formed on a charged surface of a photoconductive drum. The image is developed with toner into a toner image and the toner image is transferred to a recording medium. A charging roller is in contact with the photoconductive drum and charges the photoconductive drum when the charging roller receives a high voltage. A detector detects a characteristic such as an electrical resistance of the charging roller and outputs a signal indicative of the characteristic. A charging power supply applies a high voltage to the charging roller, the voltage having a value in accordance with the signal. A neutralizing device neutralizes the charged surface of the photoconductive drum before the detector detects the characteristic of the charging roller but does not neutralize the charged surface of the photoconductive drum when the electrostatic latent image is being formed.

Image forming apparatus including a charging power supply and a neutralizing device

An electrophotography apparatus has a charging unit, and an exposing unit, and a developing unit. The charging unit charges the surface of a rotating image bearing body having an axis of rotation. The exposing unit emits light to illuminate the surface of the image bearing body to form an electrostatic latent image on the surface. The developing unit applies charged toner to the electrostatic latent image to develop the electrostatic latent image into a visible image. The electrophotography apparatus includes, for example two electrodes and power supplies for applying voltages to the electrodes. The electrodes are disposed between the light-emitting surface of the exposing unit and extend parallel to the axis of rotation of the image bearing body. The electrodes are aligned on opposite sides of the light emitted from the exposing unit. The electrodes receive voltages from the power supplies, creating electric lines of force at an angle with a direction of the light so that the charged toner particles remaining on the image bearing body fly in a direction deviating from the direction of the light. The electrodes may be disposed in a plane perpendicular to the direction of light and receive voltages of different values from each other and of the same polarity as the charged powdered particles. The electrodes may be disposed in different planes perpendicular to the direction of light, one of the electrodes being closer to the image bearing body than the other.

Growing community of inventors

Tokyo, Japan

Kenichi Ashida