Kyocera Document Solutions Inc.

Yasuhiro Tauchi

Tamotsu Shimizu

Masashi Fujishima

Yuji Toyota

Norio Kubo

Akira Matayoshi

Chikara Ishihara

Asami Sasaki

Yasuhiro Oishi

Akihiro Watanabe

Akifumi Yamaguchi

Koji Suenami

Yukimasa Watanabe

Yu Sasaki

Sakae Saito

Yoshimi Shimizu

Yukari Ota

Hiroaki Sakai

Takashi Somete

Shinji Otani

Kazunori Tanaka

Masaki Kadota

Kosuke Uchida

Kenichi Tamaki

Kazuya Yamashita

Eiji Gyotoku

Yuji Kamiyama

Shizuka Okada

Yoshinobu Yoneima

Ryo Yamada

Uto Syu

A developing device includes a developing container storing a two-component developer containing a magnetic carrier and a toner, a developer carrying member carrying the developer on its outer circumferential surface, and a regulation member arranged to be opposed at a prescribed distance to the developer carrying member. The developer carrying member includes a developing sleeve on which a magnetic brush is formed, and a magnet secured in the developing sleeve and having a plurality of magnetic poles including a regulation pole opposed to the regulation member and a downstream-side magnetic pole arranged downstream of the regulation pole with respect to the rotation direction of the developing sleeve. The magnet is such that the vertical magnetic force gradient [mT/°] has a local minimum value near a position at which the vertical magnetic force is 0 [mT] between the downstream-side surface of the regulation member and the downstream-side magnetic pole.

Developing device and image forming apparatus including the same

A developing device includes a developing container, a first stirring conveyance member, a second stirring conveyance member, a developer carrying member including a developing sleeve and a magnet, and a regulation member. The regulation pole in the magnet has a region extending over 10° or more in which a maximum value of a vertical magnetic force is not more than 65 [mT] and a vertical magnetic force gradient is not more than 0.3 [mT/°]. A peak position of the vertical magnetic force gradient of the regulation pole is arranged at a position opposed to the second stirring conveyance member, and when a value of the vertical magnetic force gradient and a value of the vertical magnetic force at the peak position of the vertical magnetic force gradient are indicated as A [mT/°] and K [mT], respectively, A≥2.8 and A×K≥62.5 are satisfied.

Developing device including developer carrying member and containing two-component developer and image forming apparatus including the developing device

A developing device includes a developing container storing a two-component developer, a developer carrying member, and a regulation member. The developer carrying member includes a developing sleeve, and a magnet having a regulation pole opposite the regulation member and a main pole opposite the image carrying member. The regulation member is arranged downstream of the position at which the vertical magnetic force of the regulation pole is 0 [mT] but upstream of a position at which the vertical and horizontal magnetic forces of the regulation pole are equal. Let the horizontal magnetic force gradient at the position at which the horizontal magnetic force of the main pole is 0 [mT] be A and the horizontal magnetic force gradient at the upstream-side surface of the regulation member along the rotation direction of the developing sleeve be B, then |A|&#x3e;2.45 and |B|&#x3c;1.30.

An image forming apparatus includes an amorphous silicon photosensitive member, a developing device including a developer carrying member that carries a two-component developer, and a control portion. When a potential difference V0&#x2212;Vdc between the photosensitive member and the developer carrying member has a first potential difference at which the toner is moved from the developer carrying member to the photosensitive member and a second potential difference at which the toner is moved from the photosensitive member to the developer carrying member, the control portion adjusts V0 or Vdc so that the first potential difference and the second potential difference are equal in value and opposite in polarity, and a first development current |Ia| that flows at the first potential difference and a second development current |Ib| that flows at the second potential difference satisfy 1.9&#xd7;10&#x2265;|Ib|/N&#x2265;5.7&#xd7;10[&#x3bc;A/mm].

Image forming apparatus

A developing device includes a developer container, a developer carrier, and first and second stirring/conveying members. The developer container includes a first partition wall partitioning between the two conveying chambers longitudinally, a first communication portion for passing developer from the first to the second conveying chamber, a second communication portion for passing developer from the second to the first conveying chamber, a developer supply port for supplying developer in, a developer discharge portion for discharging excessive developer, a second partition wall arranged, adjacent to the regulating portion, downstream of the second communication portion to partition between the first conveying chamber and the regulating portion, and a shield portion connected to the two partition walls to bridge between them to shield a top part of the second communication portion. A gap is formed between an upper end part of the shield portion and the inner surface of the developer container.

Developing device and image forming apparatus therewith

A developing device includes a developer container, a developer carrier, and first and second members for stirring/conveying. The developer container includes a first partition wall between first and second chambers, a communication portion through which those chambers communicate at opposite ends of the first partition wall, a developer supply port, and a developer discharge portion. The first member stirs and conveys developer in the first chamber in a first direction. The second member stirs and conveys developer in the second chamber in a second direction and includes a regulating portion and a discharging blade. The developer container includes a second partition wall between the first chamber and the regulating portion. The gap from the upper end of the second partition wall to the inner surface of the developer container is larger than the gap thereto from the upper ends of a first helical blade and the regulating portion.

A bias condition determiner executes, in order, a first direct current voltage determination mode (first DC calibration) for determining a provisional reference direct current voltage that is a provisional reference for a direct current voltage of a developing bias applied to a developing roller, an inter-peak voltage determination mode (AC calibration) for determining a reference inter-peak voltage that is a reference for an inter-peak voltage of an alternating current voltage of the developing bias applied to the developing roller in an image forming operation, and a second direct current voltage determination mode (second DC calibration) for determining a reference direct current voltage that is a reference for the direct current voltage of the developing bias applied to the developing roller in the image forming operation.

A bias condition determiner executes a direct current voltage determination mode (DC calibration) for determining a reference direct current voltage that is a reference for a direct current voltage of a developing bias applied to a developing roller in an image forming operation and an inter-peak voltage determination mode (AC calibration) for determining a reference inter-peak voltage that is a reference for an inter-peak voltage of an alternating current voltage of the developing bias applied to the developing roller in the image forming operation. A calibration executor determines whether the inter-peak voltage determination mode needs to be executed in accordance with a value of the reference direct current voltage.

A bias condition determination portion of an image forming device executes each of: a first approximation expression determination operation that respectively acquires the DC component of the development current with at least three peak-to-peak voltages included in a first measurement range and determines a first expression showing a relation between the peak-to-peak voltage and the DC component of the acquired development current, a second approximation expression determination operation that respectively acquires the DC component of the development current with at least three peak-to-peak voltages included in a second measurement range larger than the first measurement range and determines a second approximation expression showing a relation between the peak-to-peak voltage and the DC component of the acquired development current, and a reference voltage determination operation that determines, as a reference peak-to-peak voltage, the peak-to-peak voltage at an intersection where the first approximation expression and the second approximation expression intersect each other.

Image forming device

Provided is an image forming apparatus capable of suppressing the occurrence of image defects in response to a difference in carrier resistance and obtaining high image quality. A developing unit has a developing roller that carries toner in a two-component developer that includes a toner and a magnetic carrier on the surface thereof, and forms a toner image on the surface of a photosensitive drum. A current detecting unit detects developing current flowing between the developing roller and the photosensitive drum when a developing voltage is applied to the developing roller by a developing power supply. When the developing voltage is applied to the photosensitive drum, a control unit derives a carrier resistance based on the developing current detected by a current detecting unit, and controls an AC amplitude of an AC voltage of the developing voltage based on the carrier resistance.

Image forming apparatus capable of suppressing occurrence of image defects in response to difference in carrier resistance and obtaining high image quality

An image forming apparatus includes a developer information acquisition unit. The developer information acquisition unit performs a developer deterioration information acquisition operation. In the developer deterioration information acquisition operation, the developer information acquisition unit acquires a tilt of a measurement straight line representing the relationship between the change amount of the frequency in a first measurement toner image forming operation and the density change amount of the measurement toner image based on the change amount of the frequency in the first measurement toner image forming operation and a result of detecting density of the measurement toner image in a density detecting unit, and acquires a toner charging amount based on the acquired tilt of the measurement straight line and the reference information in the storage unit so as to acquire information relating to deterioration of developer based on the acquired toner charging amount.

Image forming apparatus with developer information acquisition unit that acquires information relating to deterioration of developer based on an acquired toner charging amount

In the first charge amount acquisition operation, based on density of a plurality of toner images for measurement or based on a direct component of a developing current at the time of forming the plurality of toner images in addition to the density of the plurality of toner images for measurement, the charge amount acquisition section acquires a first toner charge amount that is a charge amount of toner included in the toner image for measurement. In the second charge amount acquisition operation, based on the toner density detected at the time of image formation and a relationship between the first toner charge amount and the toner density detected in the first charge amount acquisition operation, the charge amount acquisition section acquires a second toner charge amount that is a charge amount of the toner in the development device.

A developing device includes a developing roller and a layer thickness regulating member. The developing roller includes a fixed magnet and a sleeve. The layer thickness regulating member includes a regulating body portion and an upstream regulating portion, and the upstream regulating portion includes an upstream magnetic member and a nonmagnetic member. Developer is hardly strongly jammed in an area between a first magnetic field concentration point of the regulating body portion and a second magnetic field concentration point of the upstream regulating portion. Thus, even if the sleeve of the developing roller is rotated at a higher speed than before, the developer is stably regulated by the layer thickness regulating member.

Developing device with developing roller and thickness regulating member and image forming apparatus provided with same

A developing device includes a developing roller, a toner supply roller, a regulating blade, a casing, a toner-reception supporting member, a toner reception member, and a vibration generating unit. The toner-reception supporting member is opposed to the developing roller or the toner supply roller between the regulating blade and the image carrier. The toner reception member is located so as to make a downward slope toward the toner supply roller side from the image carrier side along a longitudinal direction of the toner-reception supporting member. The toner reception member has a toner receiving surface that receives the toner dropping from the developing roller. The vibration generating unit vibrates the toner reception member. The toner reception member includes a sheet-shaped toner crushing member attached to overlap approximately a whole region of the toner receiving surface in a longitudinal direction. The toner crushing member is swingably supported with respect to the toner receiving surface.

Toner-receiving and toner-supply/developing roller systems for controlling toner accumulation and drop during toner recovery

An image forming apparatus includes an image carrier, an electrification device, an exposing device, developing device, and a control unit. The developing device includes a developing roller for supplying toner to the image carrier, a developing container for storing developer containing the toner, and a seal member for preventing leakage of the toner from a gap between the image carrier and the developing container. The control unit is capable of executing a seal member cleaning mode, in which it forms an electrostatic latent image pattern having exposed parts and unexposed parts whose boundaries exist at a predetermined or less interval over the entire area in a width direction of an image forming area of the image carrier when an image is not being formed, and drives the image carrier to rotate so that the electrostatic latent image pattern passes the seal member.

Image forming apparatus having a seal member which is disposed at an opening of a developing device and of which a tip end contacts with an image carrier

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Osaka, Japan

Yasuhiro Tauchi