Abstract: An image forming apparatus includes a first image forming portion including a first photosensitive member, a first charging member, and a first developing member including a first accommodating portion: a second image forming portion including a second photosensitive member, a second charging member, and a second developing member including a second accommodating portion: an exposure portion; an applying portion: a storing portion; and a controller. When in the storing portion, information on toner accommodated in the first accommodating portion is changed from first information to second to information and information on toner accommodated in the second accommodating portion is not changed, the controller carries out control so that a transfer voltage is changed from a first transfer voltage to a second transfer voltage and so that a potential of an image portion formed on the second photosensitive member is changed from a first potential to a second potential.

Abstract: A developing device includes a developing container having an accommodation chamber for a developer and a developing chamber communicating with the accommodation chamber through a communication port, a conveyance member configured to convey the developer toward the communication port by a sheet, the conveyance member including a rotation shaft and the sheet which is flexible and has a first end fixed to the rotation shaft so as to rotate in the accommodation chamber, a light transmitting member provided in the developing container and positioned above the communication port, and an abutting portion configured to abut on a second end of the sheet such that the sheet is maintained in a bent state until the second end passes in front of the communication port from its upstream end in a rotation direction of the conveyance member and then reaches the light transmitting member.

Abstract: A developing unit includes a conveying member which rotates to convey the developer to the developer bearing member. The conveying member includes a sheet portion with one end fixed to a rotation shaft and a free end which enters the developing chamber through an opening when the conveying member rotates around a rotation center, wherein relations C>A and B>A are satisfied, where A is a distance from the rotation center to an upstream end of the opening in a rotational direction, B is a distance from the rotation center to a downstream end of the opening in the rotational direction, and C is a length from the rotation center to the free end of the sheet portion in an unbent state. The upstream end of the opening is lower in a direction of gravitational force than the downstream end at an orientation in use.

Abstract: An image forming apparatus includes a latent image forming portion configured to form a latent image on an image bearing member; a developing device including a container configured to store toner and a developing member configured to supply the toner to the latent image formed on the image bearing member to form a toner image; an environment sensor configured to detect environmental information related to an environment in which the developing device is placed; and a controller configured to control switching between a first mode and a second mode, in which a number of prints per unit time is less than that in the first mode. The controller is configured to perform switching from the first mode to the second mode based on an update value obtained by adding or subtracting over time an index value weighted in accordance with the environmental information detected by the environment sensor.

Abstract: A developing unit includes a conveying member which rotates to convey the developer to the developer bearing member. The conveying member includes a sheet portion with one end fixed to a rotation shaft and a free end which enters the developing chamber through an opening when the conveying member rotates around a rotation center, wherein relations C>A and B>A are satisfied, where A is a distance from the rotation center to an upstream end of the opening in a rotational direction, B is a distance from the rotation center to a downstream end of the opening in the rotational direction, and C is a length from the rotation center to the free end of the sheet portion in an unbent state. The upstream end of the opening is lower in a direction of gravitational force than the downstream end at an orientation in use.

Abstract: A development frame body includes a concave portion, which is projected in a direction along an upward direction of a gravitational direction, and which is located at a downstream side of a communication port and an upstream side of a replenishing port, the concave portion and the replenishing port overlap with each other in an axis direction of a shaft portion when viewed in a direction orthogonal to the axis direction, a relationship R1?L is satisfied, when a free length of the sheet portion is L and a distance from a rotation center of the shaft portion to an inner wall face is R1, and slit portions are formed in a free end of the sheet portion so that a section of the free end of the sheet portion can enter the concave portion when an agitation member is rotated.

Abstract: An image forming apparatus includes a latent image forming portion configured to form a latent image on an image bearing member; a developing device including a container configured to store toner and a developing member configured to supply the toner to the latent image formed on the image bearing member to form a toner image; an environment sensor configured to detect environmental information related to an environment in which the developing device is placed; and a controller configured to control switching between a first mode and a second mode, in which a number of prints per unit time is less than that in the first mode. The controller is configured to perform switching from the first mode to the second mode based on an update value obtained by adding or subtracting over time an index value weighted in accordance with the environmental information detected by the environment sensor.

Abstract: A development frame body includes a concave portion, which is projected in a direction along an upward direction of a gravitational direction, and which is located at a downstream side of a communication port and an upstream side of a replenishing port, the concave portion and the replenishing port overlap with each other in an axis direction of a shaft portion when viewed in a direction orthogonal to the axis direction, a relationship R1?L is satisfied, when a free length of the sheet portion is L and a distance from a rotation center of the shaft portion to an inner wall face is R1, and slit portions are formed in a free end of the sheet portion so that a section of the free end of the sheet portion can enter the concave portion when an agitation member is rotated.

Abstract: An image forming apparatus includes a latent image forming portion configured to form a latent image on an image bearing member; a developing device including a container configured to store toner and a developing member configured to supply the toner to the latent image formed on the image bearing member to form a toner image; an environment sensor configured to detect environmental information related to an environment in which the developing device is placed; and a controller configured to control switching between a first mode and a second mode, in which a number of prints per unit time is less than that in the first mode. The controller is configured to perform switching from the first mode to the second mode based on an update value obtained by adding or subtracting over time an index value weighted in accordance with the environmental information detected by the environment sensor.

Abstract: An image forming apparatus including: a latent image forming portion configured to form a latent image on an image bearing member; a developing device including a container configured to store toner, and a developing member configured to supply the toner to the latent image formed on the image bearing member to form a toner image; an environment sensor configured to detect environmental information related to an environment in which the developing device is placed; and a controller configured to control switching between a first mode and a second mode, in which a number of prints per unit time is smaller than in the first mode, wherein the controller is configured to perform switching from the first mode to the second mode based on an update value obtained by adding or subtracting over time an index value weighted in accordance with the environmental information detected by the environment sensor.

Abstract: An image forming apparatus includes a photosensitive drum for bearing a developer, a charging roller that comes into contact with the photosensitive drum at a different velocity and that charges the photosensitive drum, a transfer roller that transfers a developer image on the photosensitive drum to a recording material, and a developing sleeve that supplies a developer to the photosensitive drum and that recovers a developer on the photosensitive drum after transfer. A detecting device detects information relating to injection charging, and a controller controls an amount of the fogging developer during image formation according to information detected by the detecting device while suppressing the amount of the developer recovered in the developing sleeve.

Abstract: An image forming apparatus includes: a photosensitive drum for bearing a developer; a charging roller that comes into contact with the photosensitive drum at a different velocity and that charges the photosensitive drum; a transfer roller that transfers a developer image on the photosensitive drum to a recording material; a developing sleeve that supplies a developer to the photosensitive drum and that recovers a developer on the photosensitive drum after transfer; detecting device for detecting information relating to injection charging; and a controller that, based on the information, controls an amount of a fogging developer, wherein the controller controls the amount of the fogging developer during image formation according to information detected by the detecting device while suppressing the amount of the developer recovered in the developing sleeve.

Abstract: In an axial direction of a developing sleeve that bears magnetic developer on an outer circumferential surface thereof, ends of a sheet-shaped stirring member that stirs the magnetic developer in a container frame to move the magnetic developer toward the developing sleeve are disposed on an outer side of a region in a magnetic field region generated by a magnet roller disposed on an inner side of the developing sleeve. The region has a magnetic field strength equal to or larger than a predetermined magnetic flux density at which the magnetic developer can be borne on the surface of the developing sleeve.

Abstract: The length of a developer bearing portion of a developing device is longer than the length of a transfer roller in the rotation axis direction of a photosensitive drum. The width of a light irradiation opening of a charge eliminating device is shorter than the length of the transfer roller in the rotation axis direction of the photosensitive drum.

Abstract: What is provided is an image forming apparatus in which longitudinal end portions of a developer bearing region or longitudinal end portions of an opening are respectively located outside longitudinal end portions of a transfer bias applicable region.

Abstract: In an axial direction of a developing sleeve that bears magnetic developer on an outer circumferential surface thereof, ends of a sheet-shaped stirring member that stirs the magnetic developer in a container frame to move the magnetic developer toward the developing sleeve are disposed on an outer side of a region in a magnetic field region generated by a magnet roller disposed on an inner side of the developing sleeve, the region having a magnetic field strength equal to or larger than a predetermined magnetic flux density at which the magnetic developer can be borne on the surface of the developing sleeve.

Abstract: An image forming apparatus includes an image bearing member on which a latent image is formed, a developer carrying member for developing the latent image, and an electroconductive regulating member for regulating a layer thickness of the developer in contact with the developer carrying member. A voltage source applies, to the electroconductive regulating member, a voltage of the same polarity as a polarity of the developer on a surface of the developer carrying member at least during a developing operation. The developer remaining on the surface of the image bearing member, after a developer image formed on the image bearing member is transferred, is collected by the developer carrying member.

Abstract: Fluctuations in chargeability in an initial state are expected to be small. If a charging member is new, an image forming apparatus performs a supply operation for supplying a developer or a lubricant prior to an image forming operation in such a manner that the developer or the lubricant adheres to a surface of the charging member.

Abstract: 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.

Abstract: The length of a developer bearing portion of a developing device is longer than the length of a transfer roller in the rotation axis direction of a photosensitive drum. The width of a light irradiation opening of a charge eliminating device is shorter than the length of the transfer roller in the rotation axis direction of the photosensitive drum.