Canon Kabushiki Kaisha

Hisashi Tsukijima

Yoshiya Numata

Yusuke Ishida

Takanori Iida

Keisuke Mogi

Hiroki Takano

Masaki Maeno

Koji Suzuki

Yuichi Tanabe

Yuma Inui

Ryo Aihara

Shinya Kitago

Takashi Tsujimura

Shimpei Hanayama

Kensuke Kaneko

The image forming apparatus forms a test chart on an image bearing member, the test chart including a plurality of test images including a first test image of a first density and a second test image formed at a position different from a position of the first test image in a conveying direction of a recording medium, the second test image having a second density different from the first density. The image forming apparatus transfers the test chart to the recording medium with a transfer roller and controls the rotation velocity of the transfer roller when the recording medium passes through a transfer portion based on a result of reading the test chart on the recording medium with a reading unit.

Image forming apparatus

A calculation system includes an obtaining unit and a calculation unit. The obtaining unit obtains information of a sheet. The calculation unit calculates an amount of change in length of the sheet in a conveyance direction of the sheet heated by a heating device to fix a toner image to the sheet based on the information of the sheet obtained by the obtaining unit and an elapsed time from a time when the sheet passes through the heating device.

Calculation system, image forming apparatus, and image forming system

An image forming apparatus includes a transfer portion to transfer a toner image to a recording material, a fixing portion having a heating unit and a cylindrical rotary member and to fix the toner image to the recording material, a fixing drive portion to drive the cylindrical rotary member, and a controller. In a case in which images are formed on a plurality of recording materials, the controller controls the fixing drive portion based on a time period from a time when a trailing edge of a preceding recording material passes through the fixing portion to a time when a leading edge of a subsequent recording material passes through the fixing portion so that a second rotation speed of the cylindrical rotary member when conveying the subsequent recording material becomes lower than a first rotation speed of the cylindrical rotary member when conveying the preceding recording material.

An image forming apparatus includes a rotatable image bearing member, a rotatable transfer member, a first driving source to drive the image bearing member, a second driving source to drive the transfer member, and a control portion. Based on a toner amount per unit area of the toner image transferred to each of a plurality of first divided regions on a plane of a recording material in a feeding direction, the control portion controls a driving speed of the transfer member while each of the plurality of the first divided regions passes through a transfer portion. The control portion acquires an index value correlating with a toner amount of the toner image transferred to each of a plurality of second divided regions of each first divided region in a widthwise direction, and controls the driving speed based on the index value while the first divided region passes through the transfer portion.

A developer discharging method includes inserting a shielding member into a second communication portion via an inserting opening of a developer container to shift the second communication portion from an opening state for opening the second communication portion to a shielding state for shielding the second communication portion, and discharging the developer from a developing device via a developer discharging portion by rotatably driving a first conveying screw in a direction opposite to a direction of rotatably driving the first conveying screw during a developing operation of developing an electrostatic image formed on an image bearing member when the shielding member is inserted into the second communication portion and by rotatably driving the second conveying screw in a direction opposite to a direction of rotatably driving the second conveying screw during the developing operation when the shielding member is inserted into the second communication portion.

Developer discharging method of developing device and developing device

A developing device includes a developer container including first and second chambers, first and second communication portions to permit the developer to communicate with the first and second chambers, first and second screws provided in the first and second chambers, respectively, and a developer discharging portion. The developer discharging portion is provided in a passage continuous with the first chamber and downstream of the first communication portion. In the developing device, a discharging method includes a step for inserting a shielding member into the second communication portion via an inserting opening of the developer container, and a step for discharging the developer from the developing device via the developer discharging portion, by rotating the first and second screws in a same direction as a direction of rotating during a developing operation in a state where the shielding member is inserted into the second communication portion.

An image forming apparatus includes an image bearing member, a transfer member, a conveyance unit arranged upstream of a transfer portion in a sheet conveyance direction, an upstream conveyance unit arranged upstream of the conveyance unit, a drive unit configured to drive the conveyance unit; and a controller to control the drive unit to change a conveyance speed of the conveyance unit. In a case where a trailing edge of the sheet passes through the upstream conveyance unit after a leading edge of the sheet in the sheet conveyance direction has entered the transfer portion, the conveyance unit conveys the sheet by a first speed before the trailing edge of the sheet passes through the upstream conveyance unit, and by a second speed that is faster than the first speed after the trailing edge of the sheet has passed through the upstream conveyance unit.

An image forming apparatus includes a belt conveyance device that corrects leaning of an endless belt member, the belt conveyance device being detachably attachable to an apparatus body of the image forming apparatus; a first guiding portion that supports a first guided portion provided in a frame member supporting rotatably a first roller on which the belt member is laid under tension and guides the belt conveyance device being attached to or detached from the apparatus body; and a second guiding portion that supports a second guided portion provided in a steering unit supporting rotatably a second roller on which the belt member is laid under tension, releases the second guided portion at an attachment position of the belt conveyance device to the apparatus body, and guides the belt conveyance device being attached to or detached from the apparatus body.

A belt conveyance device has a configuration where one end of a rotation shaft of an inclinable steering roller that can move an endless belt in the width direction is supported by a first support member that is pivotable on a first pivot axis extending in a first axial line direction intersecting the rotation axis of the steering roller, and the other end of the rotation shaft of the steering roller is supported by a second support member that is pivotable on a second pivot axis that is generally parallel with the rotation axis of another suspending roller and also extends in a direction generally orthogonal to the first axial line.

Belt conveyance device and image forming apparatus

A belt conveying device is configured such that if belt deviation in which a belt moves in a direction separated from a predetermined position is detected by a belt position detection mechanism, a control unit controls a driving unit to make a steering roller to be tilted intermittently in a direction to correct the belt deviation and, if it is detected by the belt position detection mechanism that a moving direction of the belt has changed to a direction to approach the predetermined position in a suspension period between the intermittent tilting operation, suspends the subsequent tilting of the steering roller.

Belt conveying device and image forming apparatus having steering control mechanism

A belt conveyance apparatus includes an endless belt conveyed while being supported by a plurality of support rollers in a tensioned state. The plurality of support rollers include a tension roller and a steering roller. The tension roller, which is disposed adjacent to and downstream of the steering roller in a conveyance direction of the endless belt, has a reverse crown shape in which end portions in a rotational axis direction each have an outer diameter larger than a middle portion.

Belt conveyance apparatus and image forming apparatus for reduced belt buckling

A developing apparatus, includes a developer carrying member; a containing portion configured to contain developer; a discharge outlet through which a surplus of the developer is discharged; a first conveying portion configured to convey the developer; a second conveying portion provided downstream of the first conveying portion in a conveying direction of the first conveying portion and having a spiral blade portion configured to convey the developer in a conveying direction opposite to the conveying direction of the first conveying portion; and a disk portion provided upstream of the second conveying portion in the conveying direction of the second conveying portion, the disk portion being formed to project radially-outwardly from a whole circumference of a rotary shaft. An upstream end of the spiral blade portion of the second conveying portion in the conveying direction of the second conveying portion and the disk portion are arranged with an interval therebetween.

Developing apparatus having supply device with compound spiral portions

A developing device includes a developer carrying member and first and second chambers. A feeding member provided in the second chamber includes a normal feeding portion, a reverse feeding portion, and a discharging portion. An opposing portion in the second chamber opposes a peripheral surface of the reverse feeding portion and is formed so that a first region of an upper half of the reverse feeding portion is broader in clearance with the second chamber than a second region, and includes a projected portion for forming a predetermined clearance with the reverse feeding portion by being projected from a side surface of the second chamber in a horizontal direction. The projected portion is disposed higher than a rotation center of the reverse feeding portion and lower than a top of the reverse feeding portion and is more remote from the first chamber than a rotation center of the feeding member.

Developing device

A developing apparatus includes a developing container for containing a developer comprising toner and carrier and first and second rotatable feeding members configured to feed the developer. The first feeding member includes a rotatable shaft, a first helical blade portion provided around the rotatable shaft and configured to feed the developer, and a second helical blade portion provided around the rotatable shaft at a position downstream of the first helical blade portion. The second helical blade portion has a helix which is opposed to that of the first helical blade portion. In addition, a disk portion is provided on the rotatable shaft at a position between the first helical blade portion and the second helical blade portion.

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Toride, Japan

Hisashi Tsukijima