Konica Minolta Business Technologies, Inc.

Konica Minolta, Inc.

Minolta Company, Ltd.

Tetsuya Kagawa

Junji Murauchi

Hiroaki Takada

Kazuhiro Saito

Chikara Tsutsui

Masanori Murakami

Yoshiyuki Toso

Mitsutoshi Yagoto

Yoshifumi Shibata

Shigeru Tashiro

Katsuhiro Nanba

Tomohiro Kato

Syuichi Katogi

Masamitsu Ishiyama

Hirotaka Kanou

Toshio Kitaoka

Makoto Izawa

Yasuhiro Matsumoto

Nozomu Kondo

Tooru Watanabe

Kou Yamada

Yuichi Kuroyanagi

In a fixing device thermally fixing toner images on recording sheets of various sizes, (i) a conductive heat generating rotational body configured to heat toner images, (ii) an excitation coil positioned along a part of an outer circumferential surface of the heat generating rotational body and configured to generate a magnetic flux to heat the heat generating rotational body by electromagnetic induction, and (iii) a demagnetization coil positioned close to the excitation coil so as to cover a part of the excitation coil and configured to cancel, when a toner image is being fixed on a smaller-sized recording sheet, a part of the magnetic flux generated by the excitation coil so that overheating is prevented in a non sheet-passing region, are provided. The demagnetization coil has a thickness smaller than a thickness of the excitation coil in an axis direction of the coils.

Fixing device and image forming apparatus

A development device having: a main unit having formed therein a first space and a second space extending in a first direction perpendicular to a vertical direction, a first communicating portion and a second communicating portion that allow the first space and the second space to communicate with each other at both ends in the first direction; a first stirring member that extends in the first direction within the first space; a second stirring member that is positioned within the first space between the first stirring member and the second space and extends in the first direction; a conveyance member that extends in the first direction within the second space; and a developer support member that extends in the first direction within the second space.

Development device

A fixing device includes: a rotating fixing body including a resistance heating layer disposed throughout an entire periphery; and a pressure-applying member pressed against an outer peripheral surface of the rotating fixing body to form a fixing nip. The rotating fixing body further includes: a pair of electrodes each of which is a layer disposed along a different one of edges of the resistance heating layer throughout an entire periphery; and a pair of resistor layers each of which is disposed between the resistance heating layer and a different one of the electrodes. An inner edge of each resistor layer is positioned at a location corresponding to or axially more inwardly of an inner edge of the electrode. The resistor layers are higher in volume resistivity than the electrodes.

Fixing device including resistor layers having volume resistivity and image forming apparatus having fixing device

A fixing device for thermally fixing onto a sheet, an unfixed image formed on the sheet, includes: an endless belt that is heated by electromagnetic induction while being driven to rotate; a curved member that is positioned inside a rotation path of the belt and that is curved in an arc shape along the rotation path of the belt; a magnetic flux generator that (i) is positioned outside the rotation path of the belt, facing the curved member with the belt in between, and (ii) generates magnetic flux for heating the belt; a heat generation layer that is provided on the belt; a magnetic shunt alloy layer that is provided along the curved member, facing a protruding side of the curved member; and a magnetic flux nullifying layer that is provided on the curved member.

Fixing device and image formation apparatus

A housing of a developing apparatus is provided with a conveying member in a developer supplying and recovering portion, and two agitating members rotating in the same direction respectively as viewing rotating shafts from a near side in an axial direction, in a developer agitating portion. A guide is provided in an inner bottom surface of the housing between two agitating members. A braking portion suppressing a discharge of a developer is provided in a downstream side of the developer agitating portion in a developer conveying direction of the second agitating member, and a discharge portion is provided in a downstream side of a disc of the braking portion.

Developing apparatus and image forming apparatus provided with the same

A housing of a developing apparatus is provided with a conveying member in a developer supplying and recovering portion, and two agitating members rotating in the same direction respectively as viewing rotating shafts from a near side in an axial direction, in a developer agitating portion. A guide is provided in an inner bottom surface of the housing between two agitating members. A braking portion suppressing a discharge of a developer is provided in a downstream side of the developer agitating portion in a developer conveying direction of the first agitating member, and a discharge portion is provided in a downstream side of a disc of the braking portion.

A housing of a developing apparatus is provided with a conveying member in a developer supplying and recovering portion, and with two agitating members rotating from the below to the above in portions opposed to each other in a developer agitating portion. A guide is provided in an inner bottom surface of the housing between two agitating members. A braking portion suppressing a discharge of a developer is provided in a downstream side of the developer agitating portion in a developer conveying direction of the second agitating member, and a discharge portion is provided in a downstream side of a disc of the braking portion.

A housing of a developing apparatus is provided with a conveying member and two agitating members. A guide is provided in an inner bottom surface of the housing between the agitating members. The guide has a mountain shape with wide foot portion in a cross sectional shape which is orthogonal to an axial direction of rotating shafts of the agitating members. The agitating members are arranged in such a manner that gaps between respective outermost portions thereof and the inner bottom surface of the housing and the guide become equal to or more than 1.5 mm and less than 3 mm. The agitating members rotate in the same direction respectively as viewing the rotating shafts from a near side in an axial direction. A discharge portion is provided on a downstream side of the developer agitating portion in a developer conveying direction of the first and second agitating members.

A housing of a developing apparatus is provided with a conveying member and two agitating members. A guide is provided in an inner bottom surface of the housing between two agitating members. A guide is formed into a mountain shape with wide foot portion in a cross sectional shape which is orthogonal to an axial direction of rotating shafts of the agitating members. The guide is arranged in such a manner that a gap between respective outermost portions of two agitating members, and an inner bottom surface of the housing and the guide becomes equal to or more than 1.5 mm and less than 3 mm. Further, each of two agitating members rotates in a direction from the below to the above at a position of the guide.

A housing of a developing apparatus is provided with a conveying member and first and second agitating members. A guide is provided in an inner bottom surface of the housing between the first and second agitating members. The guide has a mountain shape with a wide foot portion in a cross sectional shape which is orthogonal to an axial direction of rotating shafts of the first and second agitating members. The first and second agitating are arranged in such a manner that gaps between respective outermost portions thereof and the inner bottom surface of the housing and the guide become equal to or more than 1.5 mm and less than 3 mm. A discharge portion is provided on a downstream side of a developer agitating portion in a developer conveying direction of the first and second agitating members.

Developing apparatus with agitating portion and image forming apparatus provided with the same

Disclosed is a fixing device that easily suppresses an excessive temperature increase in a guide plate without extending a warm-up period, the device comprising: guide platethat includes a low-resistance, electrically conductive layer, and guides fixing beltin its rotation direction by contacting its inner surface inside its rotation path; and magnetic flux generatorthat is positioned outside the rotation path, facing guide platewith fixing beltin between, and generates magnetic flux. Fixing beltincludes heat generation layer, which generates heat due to the magnetic flux, and magnetic shunt alloy layer, which turns from ferromagnetic to nonmagnetic when a temperature thereof has exceeded a predetermined temperature. At least one of ends of guide platein the rotation direction is thick portionhaving a greater thickness than a central portion of guide plate

A housing of a developing apparatus is provided with a conveying member in a developer supplying and recovering portion, and with first and second agitating members rotating from the below to the above in portions opposed to each other in a developer agitating portion. A guide is provided in an inner bottom surface of the housing between the first and second agitating members. A discharge portion provided with a developer discharge port is provided on a downstream side of the developer agitating portion in a developer conveying direction of the first agitating member. A suitable amount of developer can be circulated while conveying a part of an excess amount of developer in a circulating conveying path to the discharge portion and discharging from the developer discharge port. Packing and leaking of the developer within the developing apparatus and breakage of the developing apparatus can be prevented and also a good image can be obtained even if high printing images are continuously provided.

Developing apparatus including guide for preventing packing and leaking of developer and image forming apparatus provided with the same

In an image forming apparatus having a fixing rotor () that is driven to rotate and fixes an image by heating a recording paper while conveying the paper pressurized against the rotor, an excitation coil () that is provided extending in an axial direction along the fixing rotor () and causes induction heating by applying an alternating magnetic field to the fixing rotor (), and a demagnetizing coil () that is provided superposed on an end of the excitation coil () and is able to partially diminish a magnetic flux generated by the excitation coil (), by making the shape of the portion that belongs to the demagnetizing coil () and overlaps the excitation coil () has an asymmetrical shape have no axis of symmetry in the direction in which the recording paper is conveyed, a trouble due to overheating and defective fixing due to a shortage in the generation of heat can be reduced even when a plurality of kinds of recording papers of slightly different sizes are used.

There is provided a fixing deviceincluding a heating bodywhich has a heating heat generation sectionsubjected to induction heating upon application of alternating magnetic fields generated by a exciting coil, a pressure rollerwhich has a pressing heat generation sectionbeing higher in magnetic permeability than the heating heat generation sectionand being subjected to induction heating by a part of magnetic flux in the alternating magnetic fields leaking from the heating heat generation section, and a drive circuit for applying drive voltage to the exciting coil, wherein a rate of the alternating magnetic fields leaking from the heating heat generation sectionis changed by frequencies of the drive voltage.

Growing community of inventors

Toyokawa, Japan

Tetsuya Kagawa