Oki Data Corporation

Oki Electric Industry Co., Ltd.

Koichi Matsuzaki

Kuniharu Hayashi

Masamitsu Nagamine

Toru Ishihara

Katsuyuki Ito

Shinichi Katakura

An image formation method includes: transferring a first developer image for an image formed based on image data and a second developer image for adhesion onto a print medium; folding the print medium with the first and second developer images transferred thereto; and fixing the first and second developer images to the folded print medium.

Image formation apparatus and image formation method for forming an image on a folded print medium

A development unit including: a developer carrier configured to carry a developer, and capable of supplying the carried developer to an electrostatic latent image; and a developer supplying member configured to supply the developer to the developer carrier and having a surface thereof made of a foamed body. Relationships expressed by v&#x3c;S/10 and S/Dv&#x2266;125 are satisfied, where a cell opening size of the foamed body is S [&#x3bc;m], a volume mean particle diameter of the developer is Dv [&#x3bc;m], and a volume ratio of particles having a particle diameter of 5 [&#x3bc;m] or less to the total developer is v [%].

Development unit and image forming apparatus using the same

A developer container includes: an outer case; an ejection opening that is rectangular and formed on the outer case and extends longitudinally along an axial direction of the outer case, and from which a developer is ejected by a weight of the developer. A toner ejection index that is calculated from S/&#x3bc;dM is equal to or more than 0.79, where &#x3bc; is a degree of agglomeration of the developer, d is a compact density, M is a fill amount of the developer and S is the area of the ejection opening.

Developer container, developing device and image forming device

An image forming apparatus includes data conversion, charging, exposure, developer supply, image density calculation, determination and voltage change mechanisms. The data conversion mechanism converts image data into printing data. The charging mechanism charges an image carrier. The exposure mechanism forms an electrostatic latent image on the image carrier based on the printing data. The developer supply mechanism supplies a developer to the image carrier having the electrostatic latent image with an electrostatic force. The image density calculation mechanism calculates an image density of an image having a predetermined number of lines in the printing data. The determination mechanism determines whether a voltage to be applied to the developer supply mechanism is changed based on a calculation result by the image density calculation mechanism. The voltage change mechanism changes the voltage to be applied to the developer supply mechanism based on a determination result by the determination mechanism.

Image forming apparatus having a voltage change determiner

An image forming apparatus prints an image on paper. A developing roller supplies toner to an electrostatic latent image on a photoconductive drum to form a toner image. A developing blade forms a thin layer of toner on the developing roller. A transfer unit transfers the toner image onto the paper. A fixing unit fixes the toner image on the paper into a permanent image. The developing roller rotates at a circumferential speed from 150 to 250 mm/sec. The developing blade applies a line pressure in the range of 34-68 gf/cm to the developing roller. The toner has a glass transition temperature Tg from 45 to 77&#x25a1;, a softening temperature from 58 to 98&#x25a1;, a flow-beginning temperature Ts from 78 to 138&#x25a1;, and a melting point Tm from 105 to 189&#x25a1;. Tg, Ts, Tfb and Tm are related such that Tm&#x3e;Tfb&#x3e;Ts.

Image forming apparatus

A developing device includes a developer bearing body disposed in opposition to a latent image bearing body for bearing a latent image thereon. The developer bearing body develops the latent image using a developer. The developer has a degree of circularity greater than or equals to 0.93. The developing device further includes a developer layer forming member that contacts the developer on the developer bearing body to thereby form a developer layer. The developer bearing body rotates at a circumferential speed within a range from 185 mm/sec to 250 mm/sec. The initial fluidity of the developer is greater than or equals to 80%, and the tapping density of the developer is less than or equals to 35%.

Circumferential speed and developer characteristics

An image forming apparatus includes an image bearing body and a developing section. An electrostatic latent image is formed on the image bearing body. The developing section includes a developing member and a toner supplying member. The developing member is in contact with the image bearing body and applies toner to the electrostatic latent image. The toner supplying member is in contact with the developing member and has a peripheral surface that moves relative to the developing member. The toner has substantially spherical particles and is supplied from above the developing section and has a saturated apparent density not more than 0.4217 g/ml. The amount of the toner deposited on the developing member is in the range of 0.5 to 1.0 mg/cm2. The layer of the toner deposited on the developing member has a surface potential in the range of &#x2212;50 to &#x2212;250 V.

Toner particles for image forming apparatus

An image-forming apparatus includes a toner-supplying roller and a developing roller that receives toner from the toner-supplying roller, the toner having either a glass transition point not higher than 67&#xb0; C. or a softening point not higher than 120&#xb0; C. The developing roller and toner-supplying roller are configured to meet a parameter F given by 1&#xd7;10&#x3c;F&#x3c;7&#xd7;10and F=&#x3b8;&#xd7;&#x3b4;&#xd7;Asp&#xd7;(Vsp+Vdv) where &#x3b8; is an angle of slide (degrees) of the developing roller, &#x3b4;is a nip (mm) formed in the toner-supplying roller in contact with the developing roller, Asp is a hardness (degrees) of a surface of the toner-supplying roller, the hardness being measured with an Asker Type F durometer, Vsp is a circumferential speed (mm/sec) of the toner-supplying roller, and Vdv is a circumferential speed (mm/sec) of the developing roller and is higher than 150 mm/sec.

Image forming apparatus having a toner-supplying roller and a developing roller configured to meet a specific parameter

An image forming apparatus includes an image bearing body and a developing section. An electrostatic latent image is formed on the image bearing body. The developing section includes a developing member and a toner supplying member. The developing member is in contact with the image bearing body and applies toner to the electrostatic latent image. The toner supplying member is in contact with the developing member and has a peripheral surface that moves relative to the developing member. The toner has substantially spherical particles and is supplied from above the developing section and has a saturated apparent density not more than 0.4217 g/ml. The amount of the toner deposited on the developing member is in the range of 0.5 to 1.0 mg/cm. The layer of the toner deposited on the developing member has a surface potential in the range of &#x2212;50 to &#x2212;250 V.

A developing roller rotates in contact with a photoreceptor drum. The developing roller controls a development thorough the formation of a toner layer 50 .mu.m or less in thickness on an outer surface. The photoreceptor drum transfers a toner image formed on the outer surface by the controlled-development onto a medium. A fixation device heat-treats and fixes the toner image transferred onto the medium. A toner for the developing treatment comprises a resin having a Tg of 75.degree. C. or more as at least part of it.

Electrophotographic imaging apparatus using multi-layered toner

The developing unit of an electrostatic printer is designed to avoid under-development of the bottom part of a dark latent image due to a reduction in recycled toner. This can be accomplished by providing the developing unit with one developing roller and at least two supply rollers. Alternatively, the developing unit has just one supply roller, but the rate at which toner is transferred from the supply roller to the developing roller can be switched. As another alternative, the supply roller and developing roller are designed to turn slowly enough that development of an entire page is completely developed before reaching the point where under-development would begin.

Developing unit for an electrophotographic printer employing a supply

In an electrophotographic printer, a power supply is connected to a transfer roller to which a current is supplied at a time that a print paper is inserted between a photosensitive drum 10 and the transfer roller. Since respective print papers have different resistances from one another, a voltage according to the kind of the print paper is generated at the transfer roller at a time that a preset current is supplied to the transfer roller, and is held. A sensor is arranged for detecting the width of the print paper, and detects the width of the print paper inserted between the photosensitive drum and the transfer roller. The value of the preset current supplied to the transfer roller 14 is changed so as to adapt to the width of the print paper.

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Tokyo, Japan

Koichi Matsuzaki