Sharp Kabushiki Kaisha Corporation

Fuji Electric Co., Ltd.

Jitsuo Masuda

Masayasu Narimatsu

Teruhiko Noguchi

Atsushi Inoue

Takayuki Yamanaka

Toshihisa Ishida

Hideji Saiko

Masahiro Sakai

Eiichi Kido

Hiroshi Kinashi

Itaru Kawabata

Hiroshi Kawamoto

Katsushi Inoue

Toshiaki Ino

Hiroo Naoi

Katsuaki Sumida

Naoki Fukudo

Junji Morimoto

Katsuhiro Nagayama

Toshihide Ohgoshi

Motoyuki Itoyama

Masato Asanuma

Hiroaki Yoshida

Shigeyuki Wakada

Takashi Sakai

Yasuo Kitabatake

Yuichiro Takesue

Makoto Uehara

Ken Yamagishi

Tomoko Nishino

Kanshiro Okamoto

Yuji Okamoto

Hiroshi Ishii

Yasuyuki Ishiguro

Takahiko Kimura

Mitsuru Tokuyama

Yasutaka Maeda

Takeshi Wakabayashi

Tadasu Taniguchi

Hideaki Hagihara

Yuhi Yui

Syouichi Fujita

Toshio Nishino

Hiroshi Tatsumi

Naotaka Funayama

Yoshiharu Tsujimoto

Hirofumi Sakita

Kazuya Adachi

Keizo Fukunaga

Kouji Shinkawa

Hiroshi Kataoka

Tatsuo Tanaka

Mikie Kobayashi

Tao Ou

Tooru Nakata

Kunio Otsuki

Eisaku Hatanaka

Katuaki Sumida

Masakatsu Hayashi

An image forming apparatus and a method for cleaning a photoreceptor are realized that allow cleaning a surface of the photoreceptor to eliminate foreign substances adhering thereto, without using a special abrasive sheet. A recording sheet is fed and brought into contact with photoreceptors of all photoreceptor drums. The recording sheet is stopped by causing the vicinity of a rear end of the recording sheet to be sandwiched between a pair of registration rollers. Then, the photoreceptor drums are rotated. By this way, the cleaning is carried out to the photoreceptor.

Image forming apparatus capable of cleaning a photoreceptor, method for cleaning a photoreceptor, and computer program for causing an image forming apparatus to clean a photoreceptor

In case of a developing density correction based on a test image (patch image) density, normally, the developing density is carried out in a short period of time by correction (&#x3b3; correction) of a developing bias and a grid voltage (S). When a correction amount of the &#x3b3; correction exceeds an ordinary range, the &#x3b3; correction (S) and adjustment of toner concentration (magnetic permeability reference value) (S) are carried out in combination. Furthermore, when the toner concentration is changed, the setting of a correction reference of the &#x3b3; correction (&#x3b3; correction TBL) and correction timing of the &#x3b3; correction are accordingly changed (S, S). Therefore, in the developing density correction based on the test image density in the developing device using binary developer, it is possible to carry out the developing density correction, which is carried out in a short time, and whose correction width is wide, while maintaining the accuracy of a developing density adjustment.

Developing device, image forming device equipped therewith, and developing density adjusting method

An object of the invention is to make an exact judgment on suitability of a replaceable component such as a toner supplying container with use of an existing mechanism of an image forming apparatus, without additionally providing a data storage component designed for a consumable product which is detachably attached to the apparatus, or a data reading component to be placed in the image forming apparatus main body. In an incorporated control section, a specific part of a replaceable component, which is placed on an original platform prior to being loaded into the apparatus, is optically scanned to read image information, and, based on the reading result, whether or not the replaceable component is suitable for the image forming apparatus is judged.

Image forming apparatus and method for determining suitability of replaceable component

A developing apparatus capable of supplying a uniform thin layer of toner and of preventing toner scattering and leakage is provided, where the developing apparatus includes a supply roller for supplying toner to an outer peripheral surface of a toner carrier, the toner carrier for transferring the supplied toner by rotation and a layer thickness controlling member for controlling a thickness of the layer of the supplied toner at a predetermined value while making slide contact with the outer peripheral surface of the toner carrier via the toner, wherein the thin toner layer is supplied to an electrostatic latent image on an image carrier. The layer thickness controlling member is formed of an elastic plate to have a bent portion convex toward the toner carrier. The layer thickness controlling member is held by sealing members so that the bent portion makes elastic contact with the toner carrier outer peripheral surface over a nearly entire length of the toner carrier.

Developing apparatus

In image forming apparatuses producing recycled toner from residual toner and recycling the recycled toner, the toner composition changes, and the toner properties worsen, because the external additive contained in the collected residual toner that is collected with a cleaning portion decreases during the image formation. The residual toner that has been collected with the cleaning portion is conveyed through a conveyance path to a collected residual toner storage, and external additive is supplemented from an external additive cartridge, and mixed with being stirred to produce recycled toner. In a fresh toner storage, fresh toner and recycled toner are stirred, and when the amount of toner in a developing portion drops below a predetermined amount, toner is conveyed from the fresh toner storage through a conveyance path to the developing portion. The toner that has been conveyed to the developing portion is supplied to a photosensitive drum.

Image forming apparatus including system for recycling toner

Toner image forming means for forming toner images having chromatic colors of Y, M and C, respectively, are disposed on one side of an intermediate transfer belt, while disposing toner image forming means for forming a black toner image on the other side of the intermediate transfer belt, alone and on a most downstream side of all the toner image forming means. Further, when a toner image on the intermediate transfer belt includes toner having a reverse polarity, a transfer or developing process is controlled to reduce electrostatic attraction force acting on an image carrier, thus providing a color image forming device having a main body reduced in size and capable of faster image formation of a monochromatic image which is more frequently used, and of efficiently forming a color image by suppressing a back-transfer phenomenon and improving color reproducibility.

Tandem type color image forming device

A developing device, includes; a developing roller supporting and conveying mono component toner to a photoreceptor having a static latent image; a supplying roller pressed against the developing roller and rotated so as to supply the toner to the developing roller. In order to perform beneficial supply of the toner to the developing roller, bias voltages are applied so as to generate an electric field which will cause the toner between the developing roller and the supplying roller to be attracted to the developing roller. At a predetermined time before completion of development, the bias voltage applied to the supplying roller is switched so as to create an electric field which will cause the toner to be attracted to the supplying roller. Thus the toner residing between the developing roller and supplying roller after development is removed, whereby it is possible to prevent toner from sticking to that area on the developing roller, after development. Another configuration further includes a cleaning roller abutted on the supplying and regulating rollers. When development is completed, rotation of the developing roller is stopped. In time with this, the supplying roller, regulating roller and cleaning roller are kept on rotating for a predetermined period while the bias voltages are switched so that the direction of the electric fields acting on the toner, formed between the rollers after switching are opposite to those formed during development.

Image developing device using a toner as a developer

A cleaning element is arranged on the backside of the toner layer metering blade, i.e., the side opposite to the surface in contact with the developer support, in order to prevent the cleaning element from damaging the blade surface and the abutment surface of the metering blade against the developer support. This cleaning element is frictionally moved across the backside of the toner layer metering blade to remove stuck toner from the toner layer metering blade or prevent occurrence of buildups.

Developer unit with cleaning element

The image forming portion of this image forming apparatus includes a LSU, a photosensitive drum, a developing unit holder, a multiple number of developing units, an intermediate transfer element, a transfer element and a fixing unit. All the developing units are of an identical configuration. Therefore, for replacement of developing units, the operator may and should remove any color of developing unit in the same fashion and attach a fresh developing unit of the color in the same fashion. The image forming portion sets up the image forming conditions for individual colors in the developing order.

Image forming apparatus

A developing device having a reduced size in the horizontal direction and in which a developing agent is transported with stirring along a circulating route inside a developing tank to effectively mix newly added toner therewith and stir the mixture. A developing tank for storing developing agent therein is horizontally divided with a partition member thereby providing an upper chamber and a lower chamber. A developer roller and a stirring roller are disposed in the lower chamber. Two screw rollers are disposed in the upper chamber. An inlet opening is formed between an end of the partition member and a regulating member for restricting a layer if the developing agent adsorbed to the developing roller. A developing agent removed by the restricting member is fed through an inlet opening to the screw rollers in the upper chamber. The developing agent is mixed with fresh toner supplied through a supply inlet and transported with being stirred by the screw roller in its axial direction. Then, the developing agent is transferred to the screw roller disposed parallel to the screw roller and it is further transported and returned to the stirring roller in the lower chamber through a return port provided opposite to the screw roller. The compact construction of the developing device is realized by arranging screw rollers for stirring and transporting toner in the upper chamber.

Developing device having a reduced width in the horizontal direction

An image forming apparatus has an arrangement wherein a main charger includes a charger line corresponding to a region within a reference range on a surface of a photoreceptor and second charger lines corresponding to regions outside the reference range, and the first charger line within the reference range and the second charger lines outside the reference range are driven independently. The reference range is set on the surface of the photoreceptor as a width of a transported sheet which is most frequently used. In a processing control, in the case where toner patch density within the reference range becomes higher than toner patch density outside the reference range, an applied voltage with respect to the charger line within the reference range is increased relatively higher than an applied voltage with respect to the charger lines outside the reference range, thus uniformalizing the toner density with respect to the entire surface of the photoreceptor drum.

Image forming apparatus for controlling processing conditions in image

An image forming apparatus has a developer container, a development device for developing a latent image formed on a surface of a photoreceptor drum by supplying toner to the latent image, and an agitation roller for supplying toner to the development device and agitating the toner in the developer container. The development device and the agitation roller are installed in the developer container. Moreover, the image forming apparatus includes a flying toner detecting device for detecting an amount of toner flying from the development device, and a control unit for controlling various developer operations such as the toner related agitating operation of the agitation roller, toner supply amount, etc. in response to a result of a detection performed by the flying toner detecting device. This structure prevents the toner from flying from the development device.

Image forming apparatus with flying toner detecting device

The image forming apparatus of the invention controls the toner density by any one of the following configurations: by correcting the toner density of the developer in association with the agitation total; by controlling a process parameter so that the density of a toner patch formed on the photoreceptor corresponds to a prescribed density value and determining that developing performance of the developer is improved and canceling the toner density correction when the process parameter reaches the prescribed value; by changing the toner density reference value when the variation as to the charger output is equal to or greater than a first predetermined value and maintaining the changed toner density reference value until the variation of the charger output again becomes equal to or greater than the first predetermined value; or by prohibiting toner supply for a constant duration to prevent excessive toner supply if time from the end of the last operation of the developing unit to the start of a next operation, inclusive of the power-activation is equal to or longer the a predetermined period when the developing unit is activated to commence agitation of the developer.

Toner density control for an image forming apparatus

CPU is designed to create toner patches on the surface of the photoreceptor drum and pick up the detected data of the density of the toner patches by a photosensor. CPU calculates a correcting value .DELTA.Vg of the charger output in accordance with the picked up detected data, and compared the corrected charger output Vg with (Vgs+.alpha.) and (Vgs-.alpha.). If the corrections in the same direction are repeated in a row, k.beta. (where 0&lt;k&lt;1) is added to or subtracted from the toner density reference value. When the direction of the correction for the toner concentration reference value to be made is opposite that of the previous one, the absolute value of the correcting value for the current correction is set to be the absolute value of the previous one.

Image stabilizing method for use in an image forming apparatus

In order to effectively perform image stabilization by control of retaining initial characteristics of a photosensitive body, if correlation between initial and aged values corresponding to bright and dark part signals of the photosensitive body is such that a variation between the initial and aged values of the dark part signal (dark .DELTA.) is greater than a variation between the initial and aged values of the bright part signal (bright .DELTA.), an image stabilizer, first, controls a charging characteristic of the aged values by changing a charging output to the photosensitive body so that the bright .DELTA. and the dark .DELTA. are equal to each other. Next, the image stabilizer makes the aged characteristics of the photosensitive body virtually identical to the initial characteristics by changing an exposure output so that the aged and initial values of the dark part signal become equal to each other.

Image stabilizer

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Yamatotakada, Japan

Jitsuo Masuda