Canon Kabushiki Kaisha

Kuniaki Tamagaki

Nobuo Oshima

Akihisa Matsukawa

Takanori Watanabe

Masahiro Yoshida

Kohei Matsuda

Koichiro Takashima

Jun Miura

Takashi Mukai

Shuhei Tokiwa

Motonari Ito

Makoto Tokudome

Hiroyoshi Iwayama

Naoki Hayashi

Motoki Adachi

Taichi Sato

Satoshi Sunahara

Takayuki Kanazawa

Takayoshi Kihara

Hideo Kihara

Takashi Hiramatsu

Ryosuke Kanai

Yusuke Usui

Toshiki Okamura

Masanori Tanaka

Hiroki Tanaka

Kazuhisa Shida

Seiichi Shinohara

Satoru Motohashi

Makoto Fukatsu

Takashi Koyanagi

Yuta Isobe

Tsubasa Yoshida

An image forming apparatus includes a rotatable image bearing member, a developing member, a transfer member, and a brush contacting a surface of the image bearing member in a contact portion downstream of a transfer portion and upstream of a developing portion with respect to a rotational direction of the image bearing member. The toner which is not transferred onto a toner image receiving member is collected by the developing member. In a charging series, the toner is positioned on the same side as a normal charge polarity of the toner relative to the brush. In the contact portion, a maximum value of a contact pressure of 0.7 gf/mmor more and 3.5 gf/mmor less, a maximum contact area ratio is 18% or more and 74% or less, and a Clark-Evans index of the brush is 1 or more.

Brush having a higher contact pressure with an image bearing member at an upstream end of the brush and image forming apparatus

An image forming apparatus includes a brush member that includes a fiber yarn and that can come into contact with a surface of an image bearing member at a downstream of a transfer member and at an upstream of a charging member in a rotation direction of the image bearing member. The image bearing member and the brush member are relatively movable to a first position at which a leading end of the fiber yarn separates from the surface of the image bearing member, and a second position at which the leading end of the fiber yarn comes into contact with the surface of the image bearing member. A relative approaching direction of the brush member to the image bearing member upon relative movement from the first position to the second position is a direction from a downstream side to an upstream side in the rotation direction.

Image forming apparatus including movable brush member

An image forming apparatus includes a developer carrying member that bears and conveys developer. The developer carrying member has at least a base and a surface layer, with the surface layer having an electron donating portion that mainly donates charge to the developer when the developer and the surface layer make frictional contact to exchange charge and an electron accepting portion that mainly accepts charge from the developer when the developer and the surface layer makes frictional contact to exchange charge. A controller applies an AC voltage to the developer carrying member during a period in which an image forming operation is not performed and the developer carrying member is driven, with the AC voltage being different from that applied during an image forming period, and a rotating speed of the developer carrying member during a non-image forming period is slower than that during an image forming period.

Image forming apparatus having toner charging

Image forming apparatus

An image forming apparatus includes: an image bearing member to rotate; a charging member to charge a surface of the image bearing member; a charging voltage applying portion to apply an alternating-current voltage having a predetermined charging frequency to the charging member; and an exposing portion to perform image exposure and background exposure. A plurality of modes are settable for the image forming apparatus, and the plurality of image forming modes include image forming modes different in a background potential difference which is a potential difference between a surface potential of the image bearing member after the surface of the image bearing member is charged and before the charged surface is exposed by the exposing portion and a surface potential of a portion of the surface of the image bearing member which has been subjected to the background exposure.

Image forming apparatus having a plurality of modes different in background potential difference

An image forming apparatus in which a developer bearing member is disposed below a cleaning member, which cleans a charging member, so as to overlap with the cleaning member when viewed in a vertical direction and includes a base body and an elastic layer covering the base body and having a width in a longitudinal direction of the developer bearing member that accommodates the entire region of the cleaning member in the longitudinal direction. In the longitudinal direction, the cleaning member is disposed at a position where the entire region thereof in the longitudinal direction is accommodated in the width of the elastic layer.

Image forming apparatus, process cartridge, developing cartridge, and drum cartridge

An image forming apparatus includes an image bearing member, a developer bearing member, a fixing unit including a heating member, a rotary member which is heated by the heating member, and a nip area where the rotary member comes into contact with a sheet, and configured to perform fixing by heating a developer image transferred to the sheet and fixing the developer image to the sheet in the nip area, and a control unit configured to execute, while the fixing is not performed, a mode in which the image bearing member is rotated with the developer bearing member being in a separated position and the heating member is controlled such that a temperature of a portion of a surface of the rotary member, after the rotary member passes through the nip area, is maintained higher than the temperature of the portion during the fixing.

An image forming apparatus includes an image bearing member, a charging member, a charging voltage source, an electrostatic image forming portion, a developing device, a developing voltage source, a transfer portion, a transfer voltage source, and a controller. During image formation, the toner remaining on the image bearing member after transfer is collected into the developing device while forming an image. In a cleaning operation performed during non-image formation, while rotating the image bearing member, the controller transfers the toner from the charging member onto the image bearing member, passes the toner through the developing portion in an urged state, reverses a charge polarity of the toner to a normal polarity at a charging portion, and then transfers the toner reversed in charge polarity from the image bearing member onto the developing member at the developing portion to collect the toner in the developing device.

A developing device includes a developer bearing member, a regulating member configured to regulate an amount of the developer borne by the developer bearing member, and a toner seal member being in contact with a peripheral surface of the developer bearing member. The regulating member includes a flexible support member and a blade member supported by the support member and being in contact with the developer bearing member, an end portion of the regulating member more protrudes toward the developer bearing member than a central portion thereof in a rotation axial direction of the developer bearing member. The toner seal member is pressed along the rotation axial direction to the end portion of the regulating member in the rotation axial direction.

Developing device, process cartridge, and image forming apparatus

In an image forming apparatus configured such that developer remaining on an image bearing member without being transferred to a recording material is moved from the image bearing member to a developer bearing member and then recovered in a developer storage portion 35. When forming a second image on a rear surface of the recording material having a surface on which a first image is fixed with a fixing device, a second potential difference between surface potential of the image bearing member after charging with a charging member when forming the second image and potential of the developer bearing member is less than a first potential difference when forming a first image.

Image forming apparatus having potential difference control

An image forming apparatus is provided that includes a light-emitting unit which emits light to an image bearing member which bears a developer image and that detects presence or absence of a developer container storing developer or a shape of the developer container on the basis of the number of electrons discharged from or received by the image bearing member when the light-emitting unit emits the light.

Image forming apparatus capable of detecting presence or absence of a cartridge or a shape of the cartridge without increasing the number of components

When an outer diameter of a charging member is defined as Hc, a ratio of the circumferential velocity of the charging member to the circumferential velocity of an image bearing member is defined as Rc, an outer diameter of a developer bearing member is defined as Hd, and a ratio of the circumferential velocity of the developer bearing member to the circumferential velocity of the image bearing member is defined as Rd, the relationship Hc/Rc&#x2267;Hd/Rd is satisfied.

Image forming apparatus having simultaneous development and cleaning

An image forming apparatus includes a controller that executes a collection sequence to collect developer of opposite polarity adhering to a charging member. The controller executes the collection sequence by setting a first potential difference to allow the developer of opposite polarity to move from the charging member to an image bearing member, setting a second potential difference to allow the developer of opposite polarity to move from the image bearing member to a developer bearing member and to allow the developer of regular polarity to move from the developer bearing member to the image bearing member, setting a third potential difference to not allow the developer of regular polarity to move from the image bearing member to the charging member, and setting a fourth potential difference to allow the developer of regular polarity to move from the image bearing member to the developer bearing member.

An image forming apparatus includes a photosensitive drum life estimation mechanism which estimates wear amounts of a charge transfer layer in both of a toner bearing area and an end portion of a toner non-bearing area of a developing roller and informs a user that the photosensitive drum has reached the end of its life if, out of total wear amounts of the areas corresponding to predetermined life threshold values of the toner bearing and non-bearing areas, either of the total wear amounts reaches the threshold value.

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Kawasaki, Japan

Kuniaki Tamagaki