Sharp Kabushiki Kaisha Corporation

Shigeyuki Wakada

Eiichi Kido

Toshihide Ohgoshi

Yuhi Yui

Hiroshige Araki

Toshihiro Ota

Hiroshi Ishii

Masahiro Sakai

Atsushi Inoue

Takayuki Yamanaka

Jitsuo Masuda

Mitsuhiro Hasegawa

Nobuhiko Nakano

Satoshi Murakami

Yasuo Imai

Keiji Katoh

Hitoshi Nagahama

Hiroshi Tatsumi

Rikiya Matsuo

Yoshinori Otsuka

Takahiro Kawakami

Yoshinori Ohtsuka

Toshiaki Fujisawa

Tokio Awata

Mikie Kobayashi

In a full-color image forming apparatus including a light source for monochrome image formation that outputs light corresponding to monochrome image information and exposes a monochrome image forming photoreceptor and light sources for color image formation that output lights corresponding to color image information and expose photoreceptors for forming images of colors other than black, when the light source for monochrome image formation and the light sources for color image formation are caused to output the lights and a full-color image is formed, an optical output of the light source for monochrome image formation is set to become equal to or less than optical outputs of the light sources for color image formation, preferably, become less than the optical outputs of the light sources for color image formation.

Full-color image forming apparatus having variable power light source

A surface of a photosensitive body is charged and exposed to light to form an electrostatic latent image that is developed with toner having the same polarity as the surface. The toner image is transferred to a transfer material. During non-image forming periods a first step of applying a first voltage having the same polarity as that of the surface of the photosensitive body and an absolute value larger than the electric image forming potential of the transfer member is performed for a first period of time. In addition, a second step of applying a second voltage having an absolute value smaller than the absolute value of the electric potential of the surface of the photosensitive body to the transfer member for a second period of time not shorter than the first period of time is performed alternately with the first step.

Transfer member cleaning method and image forming apparatus

Apparatus and method for forming image

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

An object of the invention is to transport safely and reliably a unit such as a developing cartridge in which toner is used, and toner, and to reduce the dimensions and cost of an apparatus for packaging such a unit. Two buffer members are fixed to two opposite widthwise end sides of a developing cartridge, and the resultant combination is accommodated in a packaging box. Each buffer member has a hollow structure formed by blow molding a thermoplastic resin material. The toner is inserted into the interior of each buffer member from an opening thereof, and the buffer members and a non-toner-charged developing cartridge can be packaged together and transported. When the toner in each buffer member is supplied via the opening thereof to the interior of the developing cartridge after the transportation of these parts is completed, a structure in the developing cartridge for preventing the coagulation and leakage of the toner being transported can be simplified, and cost reduction can be effected. Since dead space in the packaging box is effectively utilized for the transportation of the toner, the safety of the transportation and a decrease in cost can be attained.

Apparatus and method for packaging unit having toner storage

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

An image forming apparatus, includes: a rotatable photosensitive member; a charging brush for uniformly charging the photosensitive member; a light scanning and irradiating portion for illuminating the photosensitive member scan-wise; a developing roller for supplying the toner to the static latent image on the photosensitive member to create a toner image; and a rotatable transfer roller arranged opposing the photosensitive member and urged against the photosensitive member by urging elements arranged around both ends thereof for allowing the toner image to a print medium. In this arrangement, the peripheral surface speed of the transfer roller is set at a speed slower, by less than about 2.3%, relative to the peripheral surface speed of the photosensitive member, and the length of the transfer roller is set shorter by the distance not exceeding about 6 mm than the maximum width of the reproducible print media, in the direction of the length.

Image forming apparatus

An electrophotography developing apparatus has been developed which can protect a developer holder and a layer thickness control member from damage. The device also prevents internal scattering of the developer while preventing a surplus supply of the developer to both ends on the peripheral surface of the developer holder. The unique advantages of the invention are derived through the utilization of sealing members having different elastic properties, which assume both bulk removal of excess developer while providing the needed uniform developer thickness. Another embodiment of the invention has the width of the layer thickness control member in a longitudinal direction set wider than the width of the developer holder in a longitudinal direction, and both side edges of the layer thickness control member are positioned outside both side edges of the developer holder. Proper sealing is assured by having the inner side edges of the sealing member positioned inside the side edges of the developer holder and outside the side edges of the image area of the image holder.

For input image data (`A`) before conversion, each pixel is converted into N (=3) parts. In this case, the three sub-pixels of data corresponding to a recording pixel (black pixel) are converted into recording sub-pixels on both sides of the three (`B`). This eliminates the density variation within a single pixel. Therefore, it is possible to reduce the dot spacing at slanted area, for example, and hence eliminate jaggies, providing a reproduced image easily recognized.

A developing apparatus which is equipped with a developer control member for controlling the developer on a developer supporter to a prescribed thickness, and which uses a one-component developer, characterized in that recessed sections are formed at the surface of the developer supporter to receive the developer, and the density .alpha. of particles of the developer which enter the recessed sections and the nip width L1 between the developer control member and the developer supporter satisfy the relationship: 3&lt;.alpha..multidot.L1&lt;10.

Developing apparatus having recessed sections on developing roller

A developing device attachable to and detachable from a printer using a non-magnetic monocomponent developer. Two different voltages are applied respectively to a developing roller and a toner layer thickness regulating device from a power source of the apparatus main body side through a terminal and a contacting spring. A voltage is applied directly to the developing roller from the contacting spring whereas a Zener diode is provided in a path connecting the contacting spring and toner layer thickness regulating device to apply another voltage to the toner layer thickness regulating device. The voltage applied to the toner layer thickness regulating device is dropped below the power supply voltage by the Zener voltage when a low-printing-ratio image is produced. Thus, the number of the terminals connecting the apparatus main body and developing device is reduced to one. Accordingly, defective connections at the contacting portions of the terminal can be prevented and the manufacturing costs can be reduced while a satisfactory image is produced.

Detachable developing device for providing first and second voltages for

A developer cartridge for image forming apparatuses which performs development to form images with non-magnetic, one-component type developer. The cartridge includes a developing roller for supplying developer to a photoconductor drum, a developer feed roller in non-contact with the developing roller for supply developer to the developing roller, and a developer-layer thickness control member for controlling the thickness of the developer layer on the developing roller. The developer feed roller is shaped as a regular polygonal prism. Since no recesses are formed in the surface of the regular polygonal prism, driving torque does not increase when developer is scrubbed from the prism, thus ensuring consistent operation and improved image quality. Non-magnetic, one-component type developer is compressed onto the developing roller by supplying the developer via the developer feed roller into a bottleneck between the developing roller and a developer applying member. The amount of developer which passes through the bottleneck onto the developing roller is controlled by a temporary reservoir, the pressurization thereof ensuring application of the developer to the developing roller. A control roller may be used against the developing roller to lower friction of developer, thereby preventing deposition of developer on the control roller while establishing a consistent amount of developer on the developing roller.

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Nara, Japan

Shigeyuki Wakada