Image forming apparatus

An image forming apparatus comprising:

• an image bearing member that forms an electrostatic latent image;
• a developer container that stores a developer;
• a developer carrying member that bears and conveys the developer;
• a regulating member that makes contact with the developer carrying member to regulate a layer thickness of the developer borne by the developer carrying member;
• an interval maintaining member that maintains a distance between the image bearing member and the developer carrying member;
• a power source that applies a voltage to the developer carrying member;
• and
• a controller that controls the power source, wherein
• the developer carrying member has at least a base and a surface layer,
• the surface layer contains a urethane resin having a carbonate bond and containing a tertiary amine structure, and
• the 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, the AC voltage being different from that applied during an image forming period.

An image forming apparatus comprising:

• an image bearing member that forms an electrostatic latent image;
• a developer container that stores a developer;
• a developer carrying member that makes contact with the image bearing member, and bears and conveys the developer;
• a regulating member that makes contact with the developer carrying member to regulate a layer thickness of the developer borne by the developer carrying member;
• a power source that applies a voltage to the developer carrying member;
• and
• a controller that controls the power source, wherein
• the developer bearing member has at least a base and a surface layer,
• the surface layer has an electron donating portion that mainly donates charge to the developer when the developer and the surface layer makes 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, and
• the 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.

An image forming apparatus comprising:

• an image bearing member that forms an electrostatic latent image;
• a developer container that stores a developer;
• a developer bearing member that makes contact with the image bearing member, and bears and conveys the developer;
• a regulating member that makes contact with the developer carrying member to regulate a layer thickness of the developer borne by the developer carrying member;
• a power source that applies a voltage to the developer carrying member;
• and
• a controller that controls the power source, wherein
• the developer carrying member has at least a base and a surface layer,
• the surface layer contains a urethane resin having a carbonate bond and containing a tertiary amine structure, and
• the 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.

An image forming apparatus comprising:

• an image bearing member;
• a developer carrying member that makes contact with the image bearing member and conveys a developer to the image bearing member;
• a control portion that controls a potential difference between the image bearing member and the developer carrying member;
• and
• a detecting portion that detects a state in which the image forming apparatus is used, wherein
• the developer carrying member has at least a base and a surface layer,
• the surface layer has (A) a charge donating portion that mainly donates charge to the developer when the developer and the surface layer makes frictional contact to exchange charge and (B) a charge accepting portion that mainly accepts charge from the developer when the developer and the surface layer makes frictional contact to exchange charge, and
• when the detecting portion detects a predetermined state, the control portion increases an absolute value of the potential difference at a predetermined timing so as to be larger than that before the predetermined state is detected.

An image forming apparatus comprising:

• an image bearing member;
• a developer carrying member that makes contact with the image bearing member and conveys a developer to the image bearing member;
• a layer thickness regulating member that makes contact with the developer carrying member to regulate a layer thickness of the developer borne by the developer carrying member;
• a control portion that controls a potential difference between the developer bearing member and the layer thickness regulating member;
• and
• a detecting portion that detects a state in which the image forming apparatus is used, wherein
• the developer carrying member has at least a base and a surface layer,
• the surface layer has (A) a charge donating portion that mainly donates charge to the developer when the developer and the surface layer makes frictional contact to exchange charge and (B) a charge accepting portion that mainly accepts charge from the developer when the developer and the surface layer makes frictional contact to exchange charge, and
• when the detecting portion detects a predetermined state, the control portion increases an absolute value of the potential difference at a predetermined timing so as to be larger than that before the predetermined state is detected.

An image forming apparatus comprising:

• an image bearing member;
• a developer container that stores a developer;
• a developer carrying member that is disposed in an opening of the developer container to make contact with the image bearing member and convey the developer to the image bearing member;
• a developer sealing member having one end fixed to the developer container and the other end which is a free end making sliding contact with the developer carrying member;
• a first bias application portion that applies a bias to the developer bearing member;
• and
• a second bias application portion that applies a bias to the developer sealing member, wherein
• the developer carrying member has at least a base and a surface layer,
• the surface layer has (A) a charge donating portion that mainly donates charge to the developer when the developer and the surface layer makes frictional contact to exchange charge and (B) a charge accepting portion that mainly accepts charge from the developer when the developer and the surface layer makes frictional contact to exchange charge,
• a surface of the developer sealing member has conductive properties, and
• the first bias application portion applies a bias to the developer carrying member and the second bias application portion applies a bias to the developer sealing member so that a difference between a DC component of the bias applied to the developer carrying member and a DC component of the bias on the surface of the developer sealing member is formed.

An image forming apparatus comprising:

• an image bearing member;
• a developer carrying member that makes contact with the image bearing member and conveys a developer to the image bearing member;
• and
• a control portion that controls a rotating speed of the developer carrying member, wherein
• the developer carrying member has at least a base and a surface layer,
• the surface layer has (A) a charge donating portion that mainly donates charge to the developer when the developer and the surface layer makes frictional contact to exchange charge and (B) a charge accepting portion that mainly accepts charge from the developer when the developer and the surface layer makes frictional contact to exchange charge, and
• the control portion decreases the rotating speed of the developer carrying member during a non-image forming period so as to be slower than the rotating speed during an image forming period.

An image forming apparatus comprising:

• an image bearing member;
• a developer carrying member that makes contact with the image bearing member and conveys a developer to the image bearing member;
• and
• a layer thickness regulating member that makes contact with the developer carrying member to regulate a layer thickness of the developer borne by the developer carrying member;
• a first bias application portion that applies a bias to the developer carrying member;
• and
• a third bias application portion that applies a bias to the layer thickness regulating member, wherein
• the developer carrying member has at least a base and a surface layer,
• the surface layer has (A) a charge donating portion that mainly donates charge to the developer when the developer and the surface layer makes frictional contact to exchange charge and (B) a charge accepting portion that mainly accepts charge from the developer when the developer and the surface layer makes frictional contact to exchange charge,
• the third bias application portion applies an AC bias to the layer thickness regulating member, and
• a wave number of the AC bias is one wave number or more within a period in which the developer passes through a nip at which the developer carrying member and the layer thickness regulating member make contact with each other.

An image forming apparatus comprising:

• an image bearing member;
• a developer carrying member that makes contact with the image bearing member and conveys a developer to the image bearing member;
• a control portion that controls a potential difference between the image bearing member and the developer carrying member;
• and
• a detecting portion that detects a state in which the image forming apparatus is used, wherein
• the developer carrying member has at least a base and a surface layer,
• the surface layer contains a urethane resin,
• the urethane resin has a carbonate bond and contains a tertiary amine structure, and
• when the detecting portion detects a predetermined state, the control portion increases an absolute value of the potential difference at a predetermined timing so as to be larger than that before the predetermined state is detected.

An image forming apparatus comprising:

• an image bearing member;
• a developer carrying member that makes contact with the image bearing member and conveys a developer to the image bearing member;
• a layer thickness regulating member that makes contact with the developer bearing member to regulate a layer thickness of the developer borne by the developer carrying member;
• a control portion that controls a potential difference between the developer bearing member and the layer thickness regulating member;
• and
• a detecting portion that detects a state in which the image forming apparatus is used, wherein
• the developer carrying member has at least a base and a surface layer,
• the surface layer contains a urethane resin,
• the urethane resin has a carbonate bond and contains a tertiary amine structure, and
• when the detecting portion detects a predetermined state, the control portion increases an absolute value of the potential difference at a predetermined timing so as to be larger than that before the predetermined state is detected.

An image forming apparatus comprising:

• an image bearing member;
• a developer container that stores a developer;
• a developer carrying member that is disposed in an opening of the developer container to make contact with the image bearing member and convey the developer to the image bearing member;
• a developer sealing member having one end fixed to the developer container and the other end which is a free end making sliding contact with the developer carrying member;
• a first bias application portion that applies a bias to the developer carrying member;
• and
• a second bias application portion that applies a bias to the developer sealing member, wherein
• the developer carrying member has at least a base and a surface layer,
• the surface layer contains a urethane resin,
• the urethane resin has a carbonate bond and contains a tertiary amine structure,
• a surface of the developer sealing member has conductive properties, and
• the first bias application portion applies a bias to the developer carrying member and the second bias application portion applies a bias to the developer sealing member so that a difference between a DC component of the bias applied to the developer carrying member and a DC component of the bias on the surface of the developer sealing member is formed.

An image forming apparatus comprising:

• an image bearing member;
• a developer carrying member that makes contact with the image bearing member and conveys a developer to the image bearing member;
• and
• a control portion that controls a rotating speed of the developer carrying member, wherein
• the developer carrying member has at least a base and a surface layer,
• the surface layer contains a urethane resin,
• the urethane resin has a carbonate bond and contains a tertiary amine structure, and
• the control portion decreases the rotating speed of the developer carrying member during a non-image forming period so as to be slower than the rotating speed during an image forming period.

An image forming apparatus comprising:

• an image bearing member;
• a developer carrying member that makes contact with the image bearing member and conveys a developer to the image bearing member;
• and
• a layer thickness regulating member that makes contact with the developer carrying member to regulate a layer thickness of the developer borne by the developer carrying member;
• a first bias application portion that applies a bias to the developer carrying member;
• and
• a third bias application portion that applies a bias to the layer thickness regulating member, wherein
• the developer carrying member has at least a base and a surface layer,
• the surface layer contains a urethane resin,
• the urethane resin has a carbonate bond and contains a tertiary amine structure,
• the third bias application portion applies an AC bias to the layer thickness regulating member, and
• a wave number of the AC bias is one wave number or more within a period in which the developer passes through a nip at which the developer carrying member and the layer thickness regulating member make contact with each other.