Kyocera Mita Corporation

Kyocera Document Solutions Inc.

Mitsuhiro Hashimoto

Akira Matayoshi

Tamotsu Shimizu

Hiroshi Inui

Kazuhiro Nakachi

Takahiro Okubo

Shiro Kaneko

Takeshi Watanabe

Hiroshi Yamazaki

Yukihiro Mori

Tomohide Hozono

Yoshinori Horiuchi

Yohei Wakasa

Provided is an image forming apparatus having a simple configuration capable of measuring a toner current included in a developing current and accurately calculating a toner charge amount based on the measurement result. A developing device has a developer carrier that carries a two-component developer including a magnetic carrier and toner. A developing voltage power supply applies a developing voltage obtained by superimposing an AC voltage on a DC voltage on the developer carrier. A control unit estimates a toner charge amount based on a toner current calculated by subtracting a carrier current from a developing current detected by a current detecting unit when a reference image is formed during non-image formation, and a toner developing amount calculated from the density of a reference image detected by a density detecting device.

Image forming apparatus having simple configuration and capable of measuring toner current included in developing current, and accurately calculating toner charge amount based on measurement result

An image forming apparatus includes an image forming portion, a high-voltage generation circuit, a current detection portion and a control portion. The image forming portion includes an image carrying member, a charging device, an exposure device and a developing device which includes a developer carrying member for carrying a two-component developer. The control portion can perform a transfer memory prediction mode that includes a step of estimating, when a first reference image is formed, the level of occurrence of transfer memory based on the direct-current component of a development current flowing through the developer carrying member and a step of measuring, when the measured direct-current component of the development current is larger than a predetermined value, the amount of charge of the toner within the developing device and estimating the cause of occurrence of the transfer memory based on the measured amount of charge of the toner.

Image forming apparatus capable of predicting the level of occurrence of a transfer memory and the cause of occurrence thereof

An image forming apparatus includes an image forming portion, a high-voltage generation circuit, a current detection portion and a control portion. The image forming portion includes an image carrying member, a charging device, an exposure device and a developing device which includes a developer carrying member for carrying a developer including a carrier and a toner. The control portion can perform a development ghost prediction mode that includes a step of measuring the amount of charge of the toner within the developing device at the time of non-image formation, a step of measuring, as a carrier current, the direct-current component of a development current when the amount of development of the toner is 0 [mg/cm] and a step of estimating the level of occurrence of development ghost and the cause of occurrence based on the amount of charge of the toner and the carrier current which are measured.

Image forming apparatus

A developing device according to the present invention includes a developer storing section storing a developer, a stirring member disposed in the developer storing section and transporting the developer while stirring the developer, a developer carrier receiving the developer from the developer storing section and carrying the developer, a developer regulating member regulating the amount of the developer received by the developer carrier from the developer storing section, and a heat-dissipating member disposed at a position in contact with the developer and capable of dissipating heat of the developer. The heat-dissipating member has a surface in contact with the developer and the contact surface of the heat-dissipating member has an arithmetic surface roughness Rathat is set to be equal to or less than &#x2153; of the volume average particle size of toner particles contained in the developer.

Developing device and image forming apparatus having the same

An image forming apparatus has an image former to form a toner image on an image bearer. A primary transferer transfers the toner image from the image bearer to the outer surface of an intermediate transferer as primary transfer by applying a primary transfer bias. A secondary transferer transfers the toner image from the outer surface of the intermediate transferer to a sheet as secondary transfer by applying a secondary transfer bias. A cleaner cleans the toner residual on the surface of the intermediate transferer after the secondary transfer by applying a cleaning bias having a polarity opposite to electric charges of the toner. A controller causes the intermediate transferer to rotate continuously and causes the primary transferer to apply the primary transfer bias until a toner image forming area on the outer surface of the intermediate transferer passes the primary transferer after the secondary transfer.

Image forming apparatus with cleaning device for removing remaining toner from outer surface of the intermediate transfer

Disclosed is an image forming apparatus, which comprises an intermediate transfer belt (), and a plurality of image-forming units () to () disposed along the intermediate transfer belt () and adapted to form toner images of different colors and sequentially transfer the toner images onto the intermediate transfer belt () in a superimposed manner so as to form a color toner image. The intermediate transfer belt () is laid across a drive roller (), a driven roller () and a tension roller (), in a tensioned condition. A rotation speed of the tension roller () adapted to apply a tension to the intermediate transfer belt () is detected to obtain a linear speed of the intermediate transfer belt (). In a process of color-misregistration correction, a write-start timing for each toner image of the colors is adjusted based on the linear speed of the intermediate transfer belt ().

An image forming apparatus includes: a plurality of rollers; and an endless belt wound around said rollers, said rollers including: a driving roller which drives said belt wound around said rollers and a driven roller set which is driven by said driving roller via the movement of the endless belt, said driven rollers having one or more metal rollers. At least one of said metal rollers is a smooth roller which satisfies following conditions (i) and (ii); (i) a surface roughness Rz&#x2266;2 &#x3bc;m; and (ii) an arithmetic inclination average &#x394;a&#x2266;0.06; where said &#x394;a is obtained from an equation (1) below: where L=a reference length taken from a roughness curve; f (x)=a height of the roughness curve at a position x within said reference length L along a lengthwise direction of the roller.

Image forming apparatus having belt wound around roller with specific roughness

The difference between the light reception output signals representing the amounts of regularly and irregularly reflected light as measured, with optical detecting means that can measure the amount of regularly and irregularly reflected light simultaneously, when no toner is adhered to a transfer belt is set as a reference value, a corrected output value is calculated by correcting, based on the reference value, the difference between the light reception output signals representing the amounts of regularly and irregularly reflected light as measured when a toner image is formed, and the amount of toner adhered to the transfer belt is calculated based on the corrected output value. With transfer belts of different colors, if their surface gloss is equal to or lower than a predetermined value, the relationship between the coverage ratio and the toner adhesion amount remains approximately identical. Thus, when a transfer belt whose initial surface gloss is equal to or lower than 20 at a measurement angle of 60 degrees, the amount of toner adhered can be measured precisely until the expiration of the warranted use period of the belt.

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Osaka, Japan

Mitsuhiro Hashimoto