Corona deterioration and moisture compensation for transfer unit in an electrophotographic apparatus

An electrographic apparatus comprising:

• an image holding member on which an image is formed;
• a transfer apparatus including charging means, a member charged by the charging means, and an object member to which the image is transferred, the object member being interposed between the charged member and the image holding member;
• and
• a circuit for generating an error signal on the basis of the electrical resistance value of the charged member.

An electrographic apparatus comprising:

• an image holding member on which an image is formed;
• a transfer apparatus including charging means, a member charged by the charging means, and an object member to which the image is transferred, the object member being interposed between the charged member and the image holding member;
• and
• output means for producing information on the charged member on the basis of the electrical resistance of the charged member.

In an electrophotographic device including an image holding member, from which an image is transferred to a target member, a transfer apparatus comprising:

• a) a charged member, said charged member
• i) adapted to hold said target member between itself and said image holding member, and
• ii) having an electrical resistance;
• b) a charger adapted to charge said charged member by providing a current;
• c) means for measuring an operation time of said charger;
• d) a measuring device adapted to measure said electrical resistance of said charged member;
• and
• e) a controller adapted to control said current provided by said charger based on a forecast of said electrical resistance of said charged member,
• wherein said forecast is determined from at least one of a charge amount which equals the product said measured charging time and said current of said charger and said charging time measured by said means for measuring.

In an electrophotographic device including an image holding member, from which an image is transferred to a target member, a transfer apparatus comprising:

• a) a charged member, said charged member
• i) adapted to hold said target member between itself and said image holding member, and
• ii) having an electrical resistance;
• b) a charger adapted to charge said charged member by providing a current;
• c) means for measuring an operation time of said charger;
• d) a measuring device adapted to measure said electrical resistance of said charged member;
• and
• e) a controller adapted to control said current provided by said charger based on a forecast of said electrical resistance of said charged member,
• wherein said forecast is determined from said operation time measured by said means for measuring.

In an electrophotographic device having a plurality of printing modes and including an image holding member, from which an image is transferred to a target member, a transfer apparatus comprising:

• a) a charged member, said charged member
• i) adapted to hold said target member between itself and said image holding member, and
• ii) having an electrical resistance;
• b) a charger adapted to charge said charged member by providing a current;
• c) a printing mode detector adapted to detect one of said plurality of printing modes;
• and
• d) a controller adapted to control said current provided by said charger based on said printing mode.

In an electrophotographic device having a plurality of printing modes and including an image holding member, from which an image is transferred to a target member, a transfer apparatus comprising:

• a) a charged member, said charged member
• i) adapted to hold said target member between itself and said image holding member, and
• ii) having an electrical resistance;
• b) a charger adapted to charge said charged member by providing a current;
• c) a printing mode detector adapted to detect one of said plurality of printing modes;
• and
• d) a controller adapted to control said current provided by said charger based on said printing mode;
• wherein said plurality of printing modes include monochromatic printing and multi-colored printing.

In an electrophotographic device having a plurality of printing modes and including an image holding member, from which an image is transferred to a target member, a transfer apparatus comprising:

• a) a charged member, said charged member
• i) adapted to hold said target member between itself and said image holding member, and
• ii) having an electrical resistance;
• b) a charger adapted to charge said charged member by providing a current;
• c) a printing mode detector adapted to detect one of said plurality of printing modes;
• and
• d) a controller adapted to control said current provided by said charger based on said printing mode;
• wherein said plurality of printing modes include an image printing area mode and a no image printing area mode.

In an electrophotographic device having a plurality of printing modes and including an image holding member, from which an image is transferred to a target member having a thickness, a transfer apparatus comprising:

• a) a charged member, said charged member
• i) adapted to hold said target member between itself and said image holding member, and
• ii) having an electrical resistance;
• b) a charger adapted to charge said charged member by providing a current;
• c) a detector adapted to detect said thickness of said target member;
• and
• d) a controller adapted to control said current provided by said charger based on said thickness of said target member detected by said detector.

In an electrophotographic device having a plurality of printing modes and including an image holding member, from which an image is transferred to a target member, a transfer apparatus comprising:

• a) a charged member, said charged member
• i) adapted to hold said target member between itself and said image holding member, and
• ii) having an electrical resistance;
• b) a charger adapted to charge said charged member by providing a current;
• c) means for measuring an operation time of said charger;
• d) a measuring device adapted to measure said electrical resistance of said charged member;
• e) a detector for detecting one of said plurality of printing modes;
• and
• f) a controller adapted to control said current provided by said charger based on a forecast of said electrical resistance of said charged member.
• wherein said forecast is determined from said operation time measured by said means for measuring and from said one of said plurality of printing modes detected by said detector.

In an electrophotographic device including an image holding member, from which an image is transferred to a target member, a transfer apparatus comprising:

• a) a charged member, said charged member
• i) adapted to hold said target member between itself and said image holding member, and
• ii) having an electrical resistance;
• b) a charger adapted to charge said charged member to one of a number of different electrical resistances by providing a current;
• c) a selector;
• and
• d) a controller adapted to control said current provided by said charger so that said electrical resistance of said charged member to one of said number of said different electrical resistances based on one of time of year or ambient operating conditions selected by said selector.

In an electrophotographic device including an image holding member, from which an image is transferred to a target member, a transfer apparatus comprising:

• a) a charged member, said charged member
• i) adapted to hold said target member between itself and said image holding member, and
• ii) having an electrical resistance;
• b) a restorer adapted to restore said electrical resistance of said charged member to at least a predetermined value;
• c) a measuring device adapted to measure said electrical resistance of said charged member;
• and
• d) a controller adapted to activate said restorer when said electrical resistance of said charged member measured by said measuring device is less than said predetermined value.