Canon Kabushiki Kaisha

Hatsuo Tajima

Atsushi Hosoi

Kimio Nakahata

Fumitaka Kan

Shunji Nakamura

Hidemi Egami

Hiroshi Tajika

Norihisa Hoshika

Nagao Hosono

Takahiro Kubo

Takashi Saito

Kenji Okado

Masaaki Yamaji

Koji Suzuki

Masanori Takenouchi

Yoshiaki Kobayashi

Katsuichi Shimizu

Tohru Takahashi

Masahide Kinoshita

Yoshikazu Yokomizo

Masahiro Inoue

Shunichi Masuda

Yuji Sakemi

Yoshihiro Kawatsura

Naoki Iwami

Junichiro Kanbe

Nobuhiro Hayashi

Masaki Uchiyama

Yasuo Mitsuhashi

Motoo Urawa

Shinkichi Takahashi

Michio Shigenobu

Shigemichi Washiyama

In a developing method, a layer of electrically charged toner particles is formed on a surface of a developer carrying member, and magnetic particles which retain on their surfaces electrically charged toner particles are dispersed on the surface of the developing carrying member. The toner particles and magnetic particles are carried on the developing carrying member to a developing position where a surface of an electrostatic latent image bearing member for bearing an electrostatic latent image is opposed with a clearance to the surface of the developer carrying member. An alternating electric field is formed at the developing position against the electrostatic image and chains of magnetic particles are formed by stationary magnetic field generating apparatus disposed behind the developer carrying member. The latent electrostatic latent image is developed by the charge toner particles on the surface of the developer carrying member and on the surface of the magnetic particles in the clearance under the alternating electric field and the stationary magnetic field.

Method for transferring toner from developer carrying member to image

An image forming apparatus includes an electrophotographic photosensitive member, a first optical device for forming a first electrostatic latent image on the photosensitive member, and a second optical device for forming a second electrostatic latent image on the photosensitive member. The first optical device includes a light source for illuminating an original to be recorded and a focusing optical system for projecting light reflected from the illuminated original onto the photosensitive member. The second optical device includes a modulated light emitting device for emitting modulated light in response to a record image signal and an optical device for exposing the modulated light onto the photosensitive member. A developer develops the first and second electrostatic latent images, an adjuster changes a luminous intensity of the light source to form the first electrostatic latent image and a controller controls a development bias voltage applied to the developer to develop the second electrostatic latent image in accordance with the change in the amount of luminous intensity of the light source.

Image forming apparatus with parallel exposure processing

A developing apparatus includes a developer layer thickness regulating zone downstream of one of magnetic poles of a stationary magnet disposed inside a developing sleeve, with respect to the rotational direction of the sleeve. In the regulating zone, there are provided a magnetic member and a non-magnetic member to regulate the layer thickness of the developer containing magnetic carrier particles and toner particles on the sleeve. The magnetic member has a width of not less than 1 mm and not more than 10 mm and a thickness of not less than 0.2 mm and not more than 3 mm.

Developing apparatus with regulating member having magnetic and

An image forming apparatus includes a first developing device having a first developer carrying member for supplying a first color toner in the first developing zone; a first voltage applying device for applying to the first developer carrying member a first oscillating bias voltage which has a first phase of time period t11 for forming a first electric field applying to the first color toner a force away from the first developer carrying member toward the image bearing member and a second phase of time period t21 for forming a second electric field applying to the first color toner a force away from the image bearing member toward the first developer carrying member; a second developing device having a second developer carrying member for supplying a second color toner in the second developing zone; and second voltage applying device intermittently applying to the second developer carrying member a second oscillating bias voltage having a third phase of time period t12 for forming a third electric field applying to the second color toner a force away from the second developer carrying member to the image bearing member and a fourth phase of time period t22 for forming a fourth electric field applying a force to the second color toner away from the image bearing member toward the second developer carrying member, wherein (t11+t21)&gt;(t12+t22), is satisfied.

Image forming apparatus

A developing apparatus includes a container having a first chamber and a second chamber, the second chamber containing a developer; a rotatable developer carrying member in the first chamber to carry the developer through a developing zone where an electrostatic latent image on an image bearing member is developed; a rotatable supply member disposed in the first chamber and cooperative with the developer carrying member to form a nip therebetween to supply the developer supplied from the second chamber to the developer carrying member; and a partition wall between the first chamber and a second chamber having an opening for permitting supply of the developer from the second chamber to the supply member, wherein the opening has a length smaller than a length of the supply member.

Developing apparatus with developer leak prevention

A color image forming method, comprising the steps of: providing a particulate developer comprising at least two species of sensitive particles which are capable of respectively absorbing lights having different wavelengths to be decolorized or faded; developing an electrostatic latent image with the particulate developer to form an image comprising the developer; and exposing the developer image to light having a wavelength capable of selectively decolorizing at least one species of the sensitive particles.

Color image forming method and particulate developer for developing

An image forming apparatus includes an image bearing member movable through first and second developing positions in the order named and a bias voltage applying device applies a first developing bias voltage to a first developer carrying member and a second developing bias voltage to a second developer carrying member. The first bias voltage has a phase of a first electric field for applying to the toner a force from the developer carrying member to the image bearing member for a period t11 in the first developing position and a phase of a second electric field in the opposite direction to the first for a period t21 in the first developing position. The second bias voltage has a phase of a third electric field for applying to the toner a force from the developer carrying member to the image bearing member for a period t12 in the second developing position and a phase of a fourth electric field in the opposite direction to the third for a period t22 in the second developing zone. A ratio of period t22 to period t12 is larger than a ratio of period t21 to period t11. A; and peak level of the second bias voltage in period t12 is larger than a peak level of the first bias voltage in period t11 and a peak level of the second bias voltage in period t22 is smaller than a peak level of the first voltage in period t21.

Image forming apparatus with AC bias voltages for preventing developer

A method of reverse development for depositing the toner particles to the light potential area of a photosensitive member. The developer used contains magnetic carrier particles and toner particles. An alternating electric field is formed in the developing position or zone. A relative volumetric ratio Q (%) of the magnetic carrier particles in the developing position satisfies 15.0.ltoreq.Q.ltoreq.28.0. The relative volumetric ratio is defined as

Developing method and device and color image forming method and

A developing apparatus including a cylindrical member having an outer diameter of 5-25 mm to carry a developer. In the cylindrical member, there is disposed a stationary magnet having only two magnetic poles adjacent an outer periphery thereof. An elastic member is contacted to said cylindrical member to regulate the thickness of the developer layer.

Developing apparatus having a two pole stationary magnet

A developing method including forming a layer of electrically charged toner particles on a surface of the developer carrying member and dispersing magnetic particles retaining on their surfaces electrically charged toner particles on the surface of the developer carrying member, carrying the particles on the developer carrying member to a developing position where a surface of an electrostatic latent image bearing member for bearing an electrostatic latent image is opposed with a clearance to the surface of the developer carrying member, applying an alternating electric field across the clearance and forming the magnetic particles into chains of the magnetic particles by magnetic field generating means disposed behind the developer carrying member, and developing the electrostatic latent image by the charged toner particles on the surface of the developer carrying member and on the surfaces of the magnetic particles.

Method and apparatus for transferring toner from carrying member to

A developing apparatus wherein a magnet is stationarily disposed within a sleeve for carrying a developer. Adjacent an outer periphery of the magnet, only two magnetic poles having different polarities. They are diametrically opposed with respect to a center of the sleeve. One of the magnetic poles form a magnetic field in the developing zone, whereas the other magnetic pole forms a magnetic field in the zone for regulating the thickness of the layer of the developer on the sleeve.

Developing apparatus

A developing method utilizing a developer including a mixture of magnetic carrier particles and toner particles wherein a stationary layer containing magnetic particles is formed on a developer carrying member in a developer container. The stationary layer is allowed to expand and contract in order to control an area of the developer supplying opening upstream of the stationary layer with respect to movement of the developer carrying member thus stabilizing the toner content in the developer supplied to the developing station.

Developer method and apparatus

A magnet is disposed in a sleeve for carrying a developer. At a position between two adjacent magnetic poles along the periphery of the magnet, an elastic plate is contacted to the sleeve. The elastic plate is effective to regulate a thickness of a layer of the developer applied on the carrying member. Of the magnetic poles, the magnetic pole disposed upstream of a contact position between the elastic plate and the sleeve with respect to the rotational direction of the sleeve provides a magnetic force F (Gauss). The elastic plate is contacted to the sleeve with the pressure P (g/cm). In this structure, 0.71P+385.ltoreq.F.ltoreq.-1.43P+1630 is satisfied.

Developing apparatus with pressure regulating member

A developing apparatus for developing an electrostatic latent image on an electrostatic latent image bearing member includes a container for containing a developer which contains toner particles and magnetic particles, a developer carrying member, opposed to the electrostatic latent image bearing member, for forming a developing position for supplying the toner particles to the latent image bearing member and for carrying the developer from the container to the developing position, magnetic field generating magnet disposed across the developer carrying member from the latent image bearing member for generating a magentic field, developer regulating member for regulating the developer which contains the toner particles and carrier particles and which is carried to the developing position, wherein the magnetic field generating magnet includes one magnetic pole adjacent an upstream side of the regulating member with respect to a movement direction of the developer carrying member, and wherein a magnetic flux density downstream of the one pole less steeply decreases the increase thereof at an upstream side.

Developing apparatus using magnetic particles and toner particles

A developing apparatus in which toner and magnetic particles are supplied to a rotatable developing sleeve to which an elastic blade is contacted. Substantially only the toner is passed through the contact portion. At the free end portion of the elastic blade, the magnetic field is concentrated. The concentrated magnetic field confines the magnetic particles.

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Matsudo, Japan

Hatsuo Tajima