Canon Kabushiki Kaisha

Katsuya Nose

Fumiyoshi Saito

Toshihisa Yago

Naoki Mugita

Yusuke Ishida

Akihiro Noguchi

Kosuke Takeuchi

Asuna Fukamachi

Takanori Iida

Kyosuke Takahashi

Yuta Okuyama

Masashi Wakisaka

Masato Kobayashi

Daigo Hotomi

An image forming apparatus includes a rotatable image bearing member, a transfer member, a cleaning blade, a driving portion, and a controller. The controller is capable of executing, at a time of an end of a job, a plurality of operations including a first reverse rotating operation, a first normal rotating operation executed subsequently to the first reverse rotating operation, a second reverse rotating operation executed after the first normal rotating operation, and a second normal rotating operation executed subsequently to the second reverse rotating operation. The controller controls the driving portion so that a movement amount of the image bearing member in the second normal rotating operation is smaller than a movement amount of the image bearing member in the second reverse rotating operation.

Image forming apparatus

A developing apparatus includes a developer bearing member and a developer container having a first chamber and a second chamber. A first conveyance screw in the first chamber conveys developer in a first direction, and a second conveyance screw in the second chamber includes a first rotation shaft portion and a first blade portion to convey the developer in a second direction. The second conveyance screw also includes a second rotation shaft portion formed coaxially with the first rotation shaft portion and a second blade portion disposed downstream of the first blade portion to convey the developer in the first direction. Each of the first blade portion and the second blade portion are disposed in the second direction to face a first communicating portion. In addition, a developer discharging portion disposed downstream of the second blade portion in the second direction discharges a part of the developer from the developing apparatus.

Developing apparatus

An image forming apparatus includes a permeability sensor configured to detect information on magnetic permeability of developer contained in a developer container for detecting toner density of the developer, and a controller configured to control a control voltage applied to the permeability sensor so that (i) a value of the control voltage that is applied to the permeability sensor in a case where a predetermined condition including a condition that the toner density of the developer contained in the developer container is a predetermined density is satisfied and an amount of the developer contained in the developer container is a first amount is greater than (ii) a value of the control voltage applied to the permeability sensor in a case where the predetermined condition is satisfied and the amount of the developer contained in the developer container is a second amount greater than the first amount.

Image forming apparatus having toner density control

An image forming apparatus includes a control portion, and in a first period from when use of a developing apparatus is started until when an amount of developer in a developing device reaches a predetermined amount larger than an amount of initial developer, when an amount of developer supplied from a supplying portion through a single supplying operation in an image forming operation is larger than a predetermined supplied amount, the control portion interrupts the image forming operation and drives a conveyance portion for a predetermined time. In a second period after the amount of the developer reaches the predetermined amount, when an amount of the supplying developer supplied through a single supplying operation in the image forming operation is larger than the predetermined supplied amount, the control portion continues the image forming operation without interruption.

Image forming apparatus having image formation interruption

An image forming apparatus includes: an image bearing member, a developing device, and a controller configured to execute an operation in a forced consumption mode. The controller includes a difference calculating portion, an integrating portion, and a flag. In a case where the flag is set when a predetermined time is elapsed after the integrated value exceeds the predetermined threshold, the image formation on the predetermined number of the recording materials is effected and then the controller executes the operation in the forced consumption mode, and in a case where the flag is reset when the predetermined time is elapsed after the integrated value exceeds the predetermined threshold, the image formation on the predetermined number of the recording materials is effected and then the controller continues an image forming operation without executing the operation in the forced consumption mode.

Image forming apparatus with forced consumption mode for toner

An image forming apparatus includes a controller configured to execute a discharging operation for discharging a toner from a developing device onto an image bearing member in a region corresponding to an interval between a recording material and a subsequent recording material in a continuous image forming job. The controller executes the discharging operation on the basis of integral information based on a relationship of a predetermined deterioration threshold with a value correlating with an amount of toner consumption. The controller changes the relationship based on a detected temperature upon toner consumption, and the controller changes the relationship so that when a temperature obtained on the basis of detected information is not less than a predetermined temperature, execution of the discharging operation is promoted more than when the obtained temperature is less than a predetermined temperature.

In a developing device in which initial developer is sealed in and a developer discharge mechanism (a trickle mechanism, or an ACR mechanism) is provided, the driving-torque load generated in the developing device is suppressed, regardless of the state of distribution of the developer that is sealed in the developing device. The order of releasing seals provided over openings is defined as follows. First, a seal provided on the downstream side of a stirring chamber starts to be released. Then, a seal provided over a discharge port is released. Lastly, a seal provided on the upstream side of the stirring chamber starts to be released.

Sealing apparatus for developing device

A developing unit includes a developing container, a developing sleeve, a developer regulating member, and a magnetic field generating portion. The magnetic field generating portion includes a drawing-up pole and a cut pole. In addition, in a peak-to-peak area, the magnetic field generating portion includes at least one of an Fr flat area in which Fr is substantially constant and an Fr attenuation area in which Fr attenuates toward the cut pole side from the drawing-up pole side, and is configured that F&#x3b8; is oriented toward the same direction as a direction of rotation of the developing sleeve in the entire peak-to-peak area.

Developing unit

An image forming apparatus includes an image bearing member, a developing device, a supplying device, and a controller. The controller can execute a normal supply mode and a forced supply mode on the basis of a difference between a toner supply amount in the normal supply mode and a supply amount of the toner to be supplied to the developing device. In a case where the flag is set when a predetermined time is elapsed after the difference exceeds the predetermined threshold, image formation is effected and then interrupted, and then the controller executes the operation in the forced supply mode, and in a case where the flag is reset when the predetermined time is elapsed after the difference exceeds the predetermined threshold, the image formation is effected and then said controller continues an image forming operation without executing the operation in the forced supply mode.

Image forming apparatus with forced supply mode for forcedly supplying toner

A developing device includes a developer carrying member, a first chamber, a second chamber, a first feeding member, and a second feeding member. The second feeding member includes first to third spiral portions and a disk portion. The disk portion includes a projected portion. When the disk portion is seen in an axial direction of the second feeding member, on the basis of a line connecting a rotation center of the disk portion and an upstream end portion of the third spiral portion with respect to a feeding direction of the third spiral portion, the projected portion is provided within a range from a position deviated by 90 degrees toward a downstream side with respect to a rotational direction of the disk portion to a position deviated by 30 degrees toward an upstream side with respect to the rotational direction of the disk portion.

Developing device

An image forming apparatus includes an image forming unit including a containing unit that contains a developer including toner and forms an image based on image data by using the toner, a supply unit that supplies the toner into the containing unit, a consumption amount calculation unit that calculates, based on information related to a density of an image corresponding to the image data, a consumption amount in the containing unit, a detection unit that detects a toner density of the developer in the containing unit, a correction amount calculation unit that calculates, based on the information and the toner density detected by the detection unit, a correction amount by which the consumption amount is corrected, and a controller that controls the supply unit based on the consumption amount and the correction amount calculated by the correction amount calculation unit.

Image forming apparatus supplying toner based on toner density of developer contained in containing unit and method for controlling image forming apparatus

A controller for an image forming apparatus includes a difference calculating portion for calculating a difference between a consumption value depending on an amount of the toner consumed every predetermined unit and a reference value; and a difference integrating portion. When an integrated value of the difference is larger than a predetermined threshold, the controller executes an operation in a forced consumption mode so that the toner is consumed in an amount corresponding to a predetermined value obtained by multiplying the predetermined threshold by a coefficient of less than 1. When the operation is executed, the integrating portion sets, at a reset value, a value obtained by subtracting the predetermined value from the integrated value at that time. After the operation is executed, the controller executes the operation every time when an integrated value obtained by integrating the reset value and the difference is larger than the predetermined threshold.

An image forming apparatus includes a developing device for developing a latent image formed on an image bearing member into a developer image; a transferring device for transferring the developer image from the image bearing member onto a transfer material; a temperature detecting sensor in a main assembly of the image forming apparatus, for detecting a temperature; and a controller for controlling a forced consumption operation in which toner is forcedly consumed by the developing device without transferring the developer image from the image bearing member onto the transfer material. The controller is capable of executing the forced consumption operation when toner consumption is below a predetermined threshold. The predetermined threshold is higher with higher temperature.

A developing device includes a developer carrying member for carrying developer containing a non-magnetic toner and a magnetic carrier to a position where the developer carrying member is opposed to an image bearing member, and a developing container including a first chamber for accommodating the developer to be supplied to the developer carrying member, a second chamber provided below the first chamber, and an opening for circulating the developer between the first chamber and the second chamber. In addition, a first feeding member and a second feeding member are rotatably provided in the first chamber and the second chamber, respectively, for stirring and feeding the developer. A first magnet member of the first feeding member and a second magnet member of the second feeding member are provided so that same magnetic polarity portions are opposed to each other or so that a ratio of a range in which the same magnetic polarity portions are opposed to each other is greater than a ratio of a range in which opposite magnetic polarity portions are opposed to each other.

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Matsudo, Japan

Katsuya Nose