Humidity corrected transfer apparatus

Claim 2

A humidity compensated apparatus for transferring charged particles from a support surface to a sheet of support material, including: a transfer member having the sheet of support material secured thereto, said transfer member cooperating electrically with the support surface to attract the charged particles to the sheet of support material; means for electrically biasing said transfer member to a potential of sufficient magnitude to attract the charged particles from the support surface to the sheet of support material; means for correcting automatically said electrical biasing means to compensate for the resistivity of differing support materials and for resistivity changes produced in said transfer member by variations in the relative humidity of the surrounding environment; and corona generating means disposed adjacent to the support surface and adapted to apply an alternating charge potential to the support surface pre-conditioning the charged particles thereon to readily facilitate the transfer thereof from the support surface to the support material by said transfer member.

Claim 3

An apparatus as recited in claim 1, wherein said correcting means adjust the biasing potential applied by said electrical biasing means to said transfer member in an inverse relationship with relative humidity variations in the surrounding environment.

Claim 4

An apparatus as recited in claim 2, wherein: said biasing means includes a voltage source; and said correcting means includes includes a resistance element electrically coupled in series with said voltage source, said voltage source and said resistance element being electrically coupled in parallel with said transfer member.

Claim 5

An apparatus as recited in claim 3, wherein: said voltage source generates, preferably, about 5000 volts; and said resistance element is, preferably, about 200 meg-ohms.

Claim 6

An apparatus as recited in claim 1, wherein said corona generating means includes: an elongated shield defining an open-ended chamber; and a corona discharge electrode mounted in the chamber of said shield and arranged therein to generate ions for pre-conditioning and charged particles on the support surface.

Claim 7

An apparatus as recited in claim 1, wherein said transfer member includes: a cylindrical core of electrically conductive material; a first layer of resilient material entrained about said cylindrical core and being substantially in contact therewith; and a second layer of resilient material entrained about said first layer of resilient material and being substantially in contact therewith.

Claim 8

An electrostatographic pringint machine of the type wherein toner particles are transferred to a sheet of support material forming thereon a copy of the original document being reproduced, including: an image bearing member having toner particles deposited thereon in image configuration; a transfer member having the sheet of support material secured thereto, said transfer member cooperating electrically with said image bearing member to attract toner particles therefrom to the sheet of support material; means for electrically biasing said transfer member to a potential of sufficient magnitude to attract the toner particles from said image bearing member to the sheet of support material; means for correcting automatically said electrical biasing means to compensate for the resistivity of differing support materials and for resistivity changes produced in said transfer member by variations in the relative humidity of the surrounding environment; and corona generating means disposed adjacent said image bearing member and adapted to apply an alternating charge potential to said image bearing member pre-conditioning the toner particles thereon to readily facilitate the transfer thereof from said image bearing member to the support material by said transfer member.

Claim 9

An electrostatographic pringint machine of the type wherein toner particles are transferred to a sheet of support material forming thereon a copy of the original document being reproduced, including: an image bearing member having toner particles deposited thereon in image configuration; a transfer member having the sheet of support material secured thereto, said transfer member cooperating electrically with said image bearing member to attract toner particles therefrom to the sheet of support material; means for electrically biasing said transfer member to a potential of sufficient magnitude to attract the toner particles from said image bearing member to the sheet of support material; means for correcting automatically said electrical biasing means to compensate for the resistivity of differing support materials and for resistivity changes produced in said transfer member by variations in the relative humidity of the surrounding environment; and corona generating means disposed adjacent said image bearing member and adapted to apply an alternating charge potential to said image bearing member pre-conditioning the toner particles thereon to readily facilitate the transfer thereof from said image bearing member to the support material by said transfer member.

Claim 10

A pRinting machine as recited in claim 7, wherein said correcting means adjusts the biasing potential applied by said electrical biasing means to said transfer member in an inverse relationship with relative humidity variations in the surrounding environment.

Claim 11

A printing machine as recited in claim 8, wherein: said biasing means includes a voltage source; and said correcting means includes a resistance element coupled in series with said voltage source, said voltage source and said resistance element being electrically coupled in parallel with said transfer member.

Claim 12

A printing machine as recited in claim 9, wherein: said voltage source generates, preferably, about 5000 volts; and said resistance element is, preferably, about 200 meg-ohms.

Claim 13

A printing machine as recited in claim 7, wherein said corona generating means includes: an elongated shield defining an open-ended chamber, and a corona discharge electrode mounted in the chamber of said shield and arranged therein to generate ions for pre-conditioning and toner particles on said image bearing member.

Claim 14

A printing machine as recited in claim 7, wherein said transfer member includes: a cylindrical core of electrically conductive material; a first layer of resilient material entrained about said cylindrical core and being substantially in contact therewith; and a second layer of resilient material entrained about said first layer of resilient material and being substantially in contact therewith.