Ricoh Company, Ltd.

Shinsuke Kikui

Naomi Sugimoto

Wataru Yasuda

Hidetoshi Yano

Makoto Obu

Hisashi Shoji

Junichi Terai

Tomoko Ogawa

Ichiro Shimeki

The surface of a photosensitive body is evenly charged by a charging member, and then the charged surface is exposed to light by an exposure device in order to produce an electrostatic latent image. A toner is caused to adhere to the latent image by a developing roller and then is transferred to paper. The temperature of the charging member is detected by a temperature detecting device and, in accordance with the detected temperature, a voltage to be applied to the charging member is corrected by a voltage correcting device. An aging change of the photosensitive body is detected by an aging change detecting device and, in accordance with the amount of the aging change, a correction rule for an applied voltage corrected by the voltage correcting device is changed by a correction rule changing device. A potential of the surface of the charged photosensitive body or a developing bias of the developing roller in an image forming process is corrected by a potential correcting device. The surface of the photosensitive body is charged with the corrected voltage and then a reference potential pattern is formed. After the correction of the potential, the amount of light of the exposure device in the image forming process is corrected by an amount-of-light correcting device on the basis of a reference potential detected when the reference potential pattern is formed.

Image forming apparatus having control of exposure and charging

A multicolor image forming apparatus of the present invention includes a first image forming condition controller for reducing the amount of toner to deposit on a photoconductive element, and therefore the amount of toner to deposit on character images. This reduces the fall of a transfer electric field ascribable to a toner layer. After an upstream image forming devices with respect to the direction of rotation of the photoconductive element has formed a toner image on the element, a second image forming condition controller again charges the toner image before transfer by use of a charger included in a downstream image forming device. This increases the amount of charge to deposit on the toner image without resorting to any extra device. A third image forming condition controller means increases a voltage or a current to be applied to a contact type transfer device, thereby enhancing desirable transfer of the toner image. The first to third controllers are selectively executed to obviate the vermicular omission of images without resorting to any extra device.

Multicolor image forming apparatus

A charging apparatus and method used in an image forming apparatus uses a charging apparatus to apply a charging potential to a photosensitive body, a voltage measuring device that measures the charging potential and outputs a measured charging potential signal, an environmental condition sensor which senses at least one environmental condition and outputs an environmental condition signal, and adjustable voltage application which applies an applied voltage to said charging member, and a controller, where the controller controls an amount of the applied voltage applied to the charging member in accordance with the charging potential signal and the environmental signal, where the applied voltage is adjusted to compensate for the sensed environmental condition.

Charging apparatus and method for use in image forming device

An image forming apparatus includes a charging member to be contacted with a rotating photosensitive body so as to charge the photosensitive body, a temperature detection device for detecting temperature of the charging member, and a voltage control device for controlling a voltage to be supplied to the charging member in accordance with a temperature value detected by the temperature detection device. The control device includes a detection temperature read device for reading the detection temperature value detected by the temperature detection device, a voltage calculation device for calculating a voltage to be supplied to the charging member based on the detection temperature value read by the detection temperature read device, and a maintenance device for maintaining a charging voltage as it is, which charging voltage is calculated last time, when a difference between the detection temperature value currently read by the detection temperature read device and the detection temperature value which is read last time by the detection temperature read device has exceeded a preset temperature value.

Image forming apparatus with contact type charging member

A voltage is supplied to a charging member by a voltage supplying device, the charging member contacts a photosensitive body, which is rotating in a predetermined direction, in order to charge its surface, temperature of the charging member is detected by a temperature detector, and the voltage to be supplied by the voltage supplying device is corrected by a voltage correcting device in accordance with the result of detection by the temperature detector. At that time, since the quality of an image is stabilized by correction of a reference supplying voltage in accordance with a target electric potential variable depending on change of temperature of the charging member, the electric potential to be charged to the surface of the photosensitive body has a plurality of target values, a reference value of the voltage to be supplied by the voltage supplying device is set per each target value, and a correction rule for a supplying voltage to be corrected by the voltage correcting device is made different by a correction rule changing device per each reference value for a target value of each electric potential to be charged.

Device for correcting an applied voltage in an image forming apparatus

An image recording apparatus for recording an image directly on a recording medium by transferring a toner to the medium. The toner is caused to fly toward the medium by small energy to form a high resolution image. A developing roller transports the toner in a predetermined direction. A flat electrode is located in the vicinity of the developing roller. A control electrode is provided on the flat electrode at a position where the flat electrode is remotest from the developing roller, while being electrically insulated from the flat electrode. The control electrode is made up of a number of recording electrodes and has an opening through which the toner may fly toward the medium.

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Yokohama, Japan

Shinsuke Kikui