Konica Minolta Business Technologies, Inc.

Konica Minolta, Inc.

Konica-minolta Holdings, Inc.

Junya Hirayama

Shigeo Uetake

Toshiya Natsuhara

Takeshi Maeyama

Masahiko Matsuura

Makiko Watanabe

Yuji Kamoda

Nofumi Mizumoto

Yuji Nagatomo

Chiaki Yamada

Hirofumi Nakagawa

Tomohiko Masuda

Atsuto Hirai

In this fixing device, a pressing roller includes a pressing roller driving unit, and a heating roller includes a heating roller driving unit. Control is performed such that torque of the heating roller in torque distribution between the pressing roller and the heating roller is greater when a belt load reducing device is activated than when the belt load reducing device is not activated. A fixing device and an image forming apparatus thus can be provided, in which the fixability according to the kind of recording medium is excellent, the durability of the fixing belt is high, and the separability between the fixing belt and the recording medium is excellent.

Fixing device and image forming apparatus

There is provided a fixing device for fixing a toner image formed on a surface of a recording medium by toner, wherein the toner includes a releasing agent and satisfies T&#x3c;T, where T(&#xb0; C.) represents a melting point of the releasing agent and T(&#xb0; C.) represents a temperature at which an elastic modulus of the toner is 1&#xd7;10Pa, the fixing device includes a first fixing portion and a second fixing portion in this order along a conveyance direction of the recording medium, the first fixing portion presses and heats the toner image such that a maximum temperature T(&#xb0; C.) of the surface of the recording medium satisfies T&#x2266;T&#x3c;T, and the second fixing portion presses and heats the toner image such that a maximum temperature T(&#xb0; C.) of the surface of the recording medium satisfies T&#x2267;T.

Fixing device, image forming apparatus and fixing method

A wet-type developing device and a wet-type image forming apparatus each employ a developer including a carrier liquid and toner particles dispersed in the carrier liquid. A charging unit is applied with positive voltage. A neutralizing unit is applied with negative voltage. The charging unit and the neutralizing unit are made different from each other in one of a sectional configuration and a length to a developer carrier such that an absolute value of a voltage-current characteristic of the neutralizing unit becomes smaller than an absolute value of a voltage-current characteristic of the neutralizing unit including a constituent element equal to a constituent element of the charging unit.

Wet-type developing device and wet-type image forming apparatus with charging unit and neutralizing unit

A fixing device includes: a non-contact heating portion that includes at least one non-contact heating unit which heats a toner image on a sheet; and a pressurizing and heating unit that is provided downstream in a sheet transport direction with respect to the non-contact heating portion and that pressurizes and heats the toner image. A time from a first point of time when the toner image reaches a toner melting temperature by heating of the non-contact heating portion to a second point of time when the toner image enters the pressurizing and heating unit is set equal to or more than a predetermined time. The predetermined time is a time when a ratio between the weight of the toner in the toner image before the entrance and the sum of the weight of the toner and the weight of the carrier liquid is equal to or more than 70%.

Fixing device

A wet-type image formation apparatus includes: an intermediate transfer body that carries a toner image including toner particles, which are charged to have a first polarity, and a carrier liquid; a transferring roller that transfers a toner image onto a transfer surface of a recording medium; a charging device that charges the transfer surface to have a second polarity opposite to the first polarity; and a fixing mechanism that fixes the toner image. The fixing mechanism includes a noncontact heating device. The noncontact heating device forms the toner particles into a film such that the toner particles and the carrier liquid are separated from each other by heating the toner image when the toner particles charged to the first polarity is electrostatically adsorbed onto the transfer surface charged to have the second polarity. The film of the toner particles is fixed onto the transfer surface.

Wet-type image formation apparatus and a charging device for charging a recording medium, and method

An image forming apparatus includes a noncontact heating device, a pressurizing and heating mechanism, and a control unit. The control unit switches an operation of the pressurizing and heating mechanism based on gloss level information of a recording medium. According to the image forming apparatus, assuming that a temperature of the recording medium after noncontact heating is T1, a temperature of the recording medium after pressurizing and heating is T2 and a toner concentration after noncontact heating is Tc1 when the gloss level information shows high gloss, and assuming that a temperature of the recording medium after noncontact heating is T3 and a toner concentration after noncontact heating is Tc2 when the gloss level information shows low gloss, the conditions of T1&#x3c;T2, T1&#x3c;T3, and Tc1&#x3c;Tc2 are satisfied.

Image forming apparatus and image forming method for forming an image on recording media with different gloss levels

An infiltration amount measuring unit is provided to measure the amount of carrier liquid infiltrated in recording paper. An output signal of the infiltration amount measuring unit is input to a control device to be used to calculate a voltage supplied to a heat source (heater) in a pre-fixing unit. A signal of a paper temperature measuring unit is input to the control device, which determines whether a target temperature is reached. The control device estimates the amount of carrier liquid in a toner layer based on the information from the infiltration amount measuring unit. Then, the pre-fixing unit is controlled such that the amount of carrier liquid in the toner layer falls within an appropriate range, based on the estimation result of the amount of carrier liquid.

Wet-type image forming apparatus with adjusting device to adjust amount of carrier liquid contained in toner image

An image forming apparatus includes a fixing device for heating and pressing a toner image on a recording medium, a non-contact heating device arranged downstream of the fixing device for heating the toner image without coming into contact with the toner image, and a pressure contact device arranged downstream of the non-contact heating device and having a smooth surface. The pressure contact device has first and second arrangement states switched according to the kind of the recording medium. In the first arrangement state, the pressure contact device is arranged so as to make pressure contact with the toner image. In the second arrangement state, the pressure contact device is arranged so as not to make pressure contact with the toner image.

Image forming apparatus controlling for glossiness

A development apparatus and an image forming apparatus wherein optical high-precision detection of the toner amount of a toner layer formed on a toner carrying member is ensured even when the great amount of the toner is deposited on the toner carrying member by transferring all or a part of the toner on the surface of the toner carrying member onto a detecting roller, and wherein stable images are provided at all times.

Development apparatus and image forming apparatus using the same

An image forming apparatus for forming an image on a recording medium includes a fixing unit configured to fix on a recording medium, a toner image formed on the recording medium, through heating and pressurization and a gloss control unit configured to lower gloss of a surface of the toner image by charging the surface of the toner image fixed onto the recording medium and heating the toner image such that toner contained in the toner image reaches a softening point or higher thereof.

Image forming apparatus and gloss control method

A wet-type image forming apparatus includes: a heating unit configured to heat a recording medium and to volatilize liquid carrier in a toner image; a fixing unit configured to fix the toner image on the recording medium and disposed at a downstream side of the heating unit in a conveyance direction of the recording medium; a conveyance unit configured to convey the recording medium from the heating unit to the fixing unit; and a housing disposed to cover the conveyance unit, wherein the recording medium is conveyed on the conveyance unit in the housing toward the fixing unit after heated by the heating unit, in the presence of gas containing the volatilized liquid carrier, and the volatilized liquid carrier is cooled and turned into fine mist liquid carrier and then the fine mist liquid carrier attaches to the recording medium before the recording medium reaches the fixing unit.

Wet-type image forming apparatus

Provided is a deposited-toner measuring apparatus capable of accurate detection of the amount of toner deposited on the toner carrying member, and an image forming apparatus equipped with the aforementioned measuring apparatus and capable of controlling the amount of toner deposited on the toner carrying member to a desired level so as to provide stable image quality at all times. A deposited-toner measuring apparatus that removes a toner layer in a part of the surface of the toner carrying member, detects change in the capacitance at the portion with a toner layer and the portion without such a toner layer, and detects the amount of the deposited toner based on the detection result of the said change in the capacitance.

Deposited toner measuring apparatus having a capacitor and a capacitance change detector for detecting a change in capacitance of the capacitor, and an image formation apparatus, and method for controlling image formation apparatus related thereto

A developer device includes two developer rollers arranged opposite to an image carrier. A first developer bias voltage (waveform Z) of a rectangular waveform obtained by superimposing an AC voltage on a DC voltage is applied to one of the developer rollers. A second developer bias voltage (waveform A) obtained by superimposing an AC voltage on a DC voltage is applied to the other developer roller. The waveform A is a waveform obtained by deforming the rectangular wave in the first developer bias voltage such that toner adhered to the image carrier is prevented from being dislodged by toner being subsequently scattered. According to the developer device, an optimal image density can be obtained at a low-density potential.

Developer device and image forming apparatus

Provided is a development device and an image forming apparatus that realize high image quality with improved decrease in density at high speed development and with reduced occurrence of development hysteresis (ghost) in a hybrid developing method having a plurality of toner carriers, by reducing the decrease in the toner supplying ability to a downstream-side toner carrier, which decrease is caused by the supply of toner to an upstream-side toner carrier on an upstream side in a rotating direction of a developer carrier. By providing a magnetic pole between main magnetic poles, of the developer carrier, facing the toner carriers, a magnetically raised bristle of developer is moved by a magnetic force, while the developer in which development hysteresis due to supplying toner to the upstream-side toner carrier occurred is conveyed to supply toner to the downstream-side toner carrier, whereby a developer layer is stirred.

Development device having developer carrier with stationary disposed magnetic body

Provided are a development apparatus and an image forming apparatus which, in a hybrid development apparatus provided with a plurality of toner carriers, a toner supply capability to supply toner to each toner carrier is controlled independent of development electric fields between the toner carriers and an image carrier, whereby each toner carrier is allowed to exhibit a desired development capability, and even in the case of high speed development, a high quality image is provided. The phases, the frequencies, and/or the duty ratios of the alternating current components of the voltages applied to the plurality of the toner carriers are made to be different, whereby the toner supply amount for each toner carrier from the developer carrier is controlled independently of the development electric fields between the toner carriers and the image carrier.

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Takarazuka, Japan

Junya Hirayama