Fuji Xerox Co., Ltd.

Suk Kim

Kazuhiko Yanagida

Susumu Yoshino

Takashi Imai

Yasuhiro Oda

Yasuo Yamamoto

Yoshifumi Iida

Masanori Ichimura

Shigeru Inaba

Taku Fukuhara

Koichi Takashima

Koichi Takahashi

Makoto Furuki

Lyong Sun Pu

Takeshi Agata

Yoshiro Yamaguchi

Masato Mikami

Akihiko Noda

The toner comprises a white color toner particle and an external additive containing a hydrophobic titanium oxide particle. The absolute charge value of the toner is 20 to 50 &#x3bc;C/g. The developer contains a white color toner particle and a carrier having a surface coated with a resin containing a fluororesin.

Toner for developing an electrostatic latent image, developer, developer unit, and method for forming an image

The present invention discloses a carrier, which comprises a core and a resin coating layer formed thereon containing electroconductive powder, wherein, when the magnetic brush is formed only of the core, the dynamic electrical resistance of the core forming the magnetic brush under an electric field of 10 V/cm is 1 &OHgr;&middot;cm or less and the electrical resistance of the resin coating layer is from 10 to 1&times;10 &OHgr;&middot;cm, a developer using the carrier, and an image-forming method using the developer. Owing to the present invention, a superior solid image, which is free of brush marks and carrier beads carry over, can be obtained.

Carrier, developer, and image-forming method

A carrier for electrophotography having a resin coating layer containing a conductive powder having an aspect ratio of not less than 3 on the core material, in which the dynamic electric resistance of the core material in a magnetic brush state under an electric field of 10.sup.4 V/cm is not higher than 1 .OMEGA..cm, and the electric resistance of the resin coating layer is within a range of from 10 to 1.times.10.sup.8 .OMEGA..cm, and a developer for an electrostatic latent image using the carrier. An image forming method on which the developing process includes using the above-mentioned developer for an electrostatic latent image, whose development curve, expressed by a contrast potential and the developing toner quantity, has a saturation area, and applying the developing bias to the developer carrying member so that the developing toner quantity shows the saturation characteristic.

Carrier for electrophotography, an electrostatic latent image developer

The present invention provides a charged member which has no reduction in the amount of electrostatic charge at high temperature and high humidity and no extreme increase in the amount of electrostatic charge at low temperature and low humidity, improves the adhesion force between a charged member and a coating layer, prevents deterioration of developer through peeling of the coating layer. It provides excellent durability without deterioration of toner through adhering of a toner to the carrier. More particularly, a carrier for electrophotography and a sleeve for electrostatic development which use as a coating material a high-molecular compound containing as an essential component the first monomer represented by the following general formula (1) and/or (2), the second monomer represented by the following general formula (3) and/or (4) and a coupling agent containing a vinyl group are provided.

Charged member for electrostatic development and sleeve for

An image forming apparatus performs a stable developing characteristic for an electrostatic latent image including a halftone image expressed by a binary manner. The apparatus includes a photoreceptor having a surface and an electrostatic image forming device for forming an electrostatic latent image on the surface of the photoreceptor, the electrostatic latent image including a digitally-reproduced binary latent image. The apparatus further includes a developing device for developing the electrostatic latent image. The developing device includes a two-component developer including magnetic carrier particles and toner particles. The apparatus also includes a bias applying device for applying a bias voltage between the developing device and the photoreceptor for defining a relatively high contrast potential of the digitally-reproduced binary latent image to be developed. The developing system includes a control system for controlling a certain amount of toner to be developed to be substantially constant corresponding to the contrast potential. Several configurations of the developing device may be adopted to the purpose.

Image forming apparatus

An image forming method wherein a developer layer formed by a layer forming material and supported on a developer supporting body is used to develop an electrostatic latent image on an electrostatic latent image supporting body, thereby forming an image. In the method, the direction of rotation of the developer supporting body is the same as that of the electrostatic latent image supporting body, the ratio of peripheral speed of the developer supporting body to the electrostatic latent image supporting body ranges from 0.7 to 1.8, the developer is composed of a carrier and a toner, and the toner contains a conductive inorganic fine powder. The method is useful for making an amount of static electrification of the toner suitable and stabilizing the same.

Image forming method

A carrier for an electrostatic latent-image developer, comprising a core material having thereon a coating layer comprising a resin and fine electroconductive particles, the resin having a work function of 4.5 eV or lower. An electrostatic latent-image developer comprising the carrier and a toner and an image forming process are also disclosed. The carrier is capable of maintaining a high build-up speed of electrification and a proper electrification level even when a charge control agent is omitted or used in a slight amount or when the addition amount of an additive such as silica and titanium oxide is reduced so as to prevent carrier fouling with a charge control agent or an external additive and to inhibit a decrease in developer life.

Carrier for electrostatic latent-image developer, electrostatic

A photosensor having a photoconductive layer made of built-up monomelecular membranes containing a squarylium pigment represented by the formula (I): ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which may be the same or different, each represents an alkyl group.

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Minami-ashigara, Japan

Suk Kim