Image forming apparatus having transfer charger which is controlled according to ambient conditions

Claim 2

An image forming apparatus, comprising: an image bearing member; means for forming a toner image on said image bearing member; transfer material carrying means for carrying a transfer material to an image transfer position to receive the toner image from said image bearing member, said transfer material carrying means including a transfer material carrying member for carrying the transfer material; contacting member contactable to said transfer material carrying member at a side of said member that is contactable to the transfer material; discharging means for applying electric charge to the transfer material carried on the transfer material carrying means; and control means for controlling an output of said discharging means in accordance with an electric current which flows through said contacting member when the transfer material passes between said transfer material carrying member and said contacting member.

Claim 3

An apparatus according to claim 1, wherein said contacting member is electrically grounded.

Claim 4

An apparatus according to claim 2, further comprising second discharging means for applying electric charge on said transfer material carrying member, said second discharging means being disposed on an opposite side of said transfer material carrying member from said contacting member, said second discharging means effecting a discharging operation when the transfer material passes between said carrying member and said contacting member.

Claim 5

An apparatus according to claim 1, wherein said discharging means is disposed on an opposite side of said carrying member from said image bearing member and is effective to transfer the toner image from said image bearing member to the transfer material carried on said carrying member.

Claim 6

An apparatus according to claim 1, wherein said toner image forming means includes means for transferring different color toner images superimposedly from said image bearing member onto the same transfer material carried on said carrying member.

Claim 7

An apparatus according to claim 5, wherein said apparatus is capable of forming a full-color toner image.

Claim 8

An apparatus according to claim 1 or 3, wherein when the transfer material passes between said carrying member and said contacting member, the transfer material is electrostatically attracted onto said carrying member.

Claim 9

An apparatus according to claim 1, wherein said contacting member is in the form of roller.

Claim 10

An apparatus according to claim 7, wherein said carrying member is in the form of a dielectric sheet.

Claim 11

An image forming apparatus, comprising: an image bearing member; means for forming a toner image on said image bearing member; transfer material carrying means for carrying a transfer material to an image transfer position to receive the toner image from said image bearing member, said transfer material carrying means including a transfer material carrying member for carrying the transfer material; a contacting member contactable to said transfer material carrying member at a side of said member that is contactable to the transfer material; discharging means for applying electric charge to the transfer material carried on the transfer material carrying member; constant current control means for maintaining a constant current supply to said contacting member as the transfer material passes between said carrying member and said contacting member; and second control means for controlling an output of said discharging means in accordance with a voltage during constant current control by said constant current control means.

Claim 12

An image forming apparatus, comprising: an image bearing member; means for forming a toner image on said image bearing member; transfer material carrying means for carrying a transfer material to an image transfer position to receive the toner image from said image bearing member, said transfer material carrying means including a transfer material carrying member for carrying the transfer material; a contacting member contactable to said transfer material carrying member at a side of said member that is contactable to the transfer material; discharging means for applying electric charge to the transfer material carried on the transfer material carrying member; constant current control means for maintaining a constant current supply to said contacting member as the transfer material passes between said carrying member and said contacting member; and second control means for controlling an output of said discharging means in accordance with a voltage during constant current control by said constant current control means.

Claim 13

An apparatus according to claim 10, wherein said contacting member is electrically grounded.

Claim 14

An apparatus according to claim 10, further comprising second discharging means for applying electric charge on said transfer material carrying member, said second discharging means being disposed sandwiching said transfer material carrying member with said contacting member, said second discharging means effecting a discharging operation when the transfer material passes between said carrying member and said contacting member.

Claim 15

An apparatus according to claim 10, wherein said discharging means is disposed on an opposite side of said carrying member from said image bearing member and is effective to transfer the toner image from said image bearing member to the transfer material carried on said carrying member.

Claim 16

An apparatus according to claim 10, wherein said toner image forming means includes means for transferring different color toner images superimposedly from said image baring member onto the seam transfer material carried on said carrying member.

Claim 17

An apparatus according to claim 14, wherein said apparatus is capable of forming a full-color toner image.

Claim 18

An apparatus according to claim 10 or 13, wherein when the transfer material passes between said carrying member and said contacting member, the transfer material is electrostatically attracted onto said carrying member.

Claim 19

An apparatus according to claim 10, wherein said contacting member is in the form of roller.

Claim 20

An apparatus according to claim 16, wherein said carrying member is in the form of a dielectric sheet.

Claim 21

An apparatus according to claim 10, wherein said second control means controls output of said discharging means in accordance with a voltage of said contacting member during the constant current control operation of said constant current control means.

Claim 22

An image forming apparatus, comprising: a recording material carrying member for carrying a recording material; image forming means for forming a toner image on the recording material carried on said recording material carrying member; contacting member contactable to said recording material carrying member; and control means for controlling an image forming condition of said image forming means in accordance with a current through said contacting member when the recording material passes between said recording material carrying member and said contacting member.

Claim 23

An image forming apparatus, comprising: a recording material carrying member for carrying a recording material; image forming means for forming a toner image on the recording material carried on said recording material carrying member; contacting member contactable to said recording material carrying member; and control means for controlling an image forming condition of said image forming means in accordance with a current through said contacting member when the recording material passes between said recording material carrying member and said contacting member.

Claim 24

An apparatus according to claim 20, wherein said image forming means includes an image bearing member and image transfer charging means for transferring the image from said image bearing member to the recording material, and said control means limits an output of said transfer charging means.

Claim 25

An apparatus according to claim 20, wherein said contacting member is electrically grounded.

Claim 26

An apparatus according to claim 20, further comprising discharging means for applying electric charge to said carrying member, said discharging means disposed such that said carrying member is between said discharging means and said contacting member, wherein when the recording material passes between said carrying member and said contacting member, said discharging means effects a discharging operation.

Claim 27

An apparatus according to claim 21, wherein said toner image forming means includes means for transferring different color toner images superimposedly from said image bearing member onto the same recording material carried on said carrying member.

Claim 28

An apparatus according to claim 24, wherein said apparatus is capable of forming a full-color toner image.

Claim 29

An apparatus according to claim 20 or 23, wherein when the recording material passes between said carrying member and said contacting member, the recording material is electrostatically attracted onto said carrying member.

Claim 30

An apparatus according to claim 20, wherein said contacting member is in the form of roller.

Claim 31

An apparatus according to claim 26, wherein said carrying member is in the form of a dielectric sheet.

Claim 32

An image forming apparatus, comprising: a recording material carrying member for carrying a recording material; image forming means for forming a toner image on the recording material carried on said recording material carrying member; a contacting member contactable to said recording material carrying member; constant current control means for maintaining constant the current supplied to said contacting member as the recording material passes between said carrying member and said contacting member; and second control means for controlling an image forming condition in accordance with a voltage during constant current control by said constant current control means.

Claim 33

An image forming apparatus, comprising: a recording material carrying member for carrying a recording material; image forming means for forming a toner image on the recording material carried on said recording material carrying member; a contacting member contactable to said recording material carrying member; constant current control means for maintaining constant the current supplied to said contacting member as the recording material passes between said carrying member and said contacting member; and second control means for controlling an image forming condition in accordance with a voltage during constant current control by said constant current control means.

Claim 34

An apparatus according to claim 29, wherein said image forming means includes an image bearing member and image transfer charging means for transferring the image from said image bearing member to the recording material, and said second control means limits an output of said transfer charging means.

Claim 35

An apparatus according to claim 29, wherein said second control means controls the image forming condition of said image forming means in accordance with a voltage of said contacting member during the constant current control operation of said constant current control means.

Claim 36

An apparatus according to claim 29, wherein said contacting member is electrically grounded.

Claim 37

An apparatus according to claim 29, further comprising discharging means for applying electric charge to said carrying member, said discharging means disposed such that said carrying member is between said discharging means and said contacting member, wherein when the recording material passes between said carrying member and said contacting member, said discharging means effects a discharging operation.

Claim 38

An apparatus according to claim 30, wherein said toner image forming means includes means for transferring different color toner images superimposedly from said image bearing member onto the same transfer material carried on said carrying member.

Claim 39

An apparatus according to claim 34, wherein said apparatus is capable of forming a full-color toner image.

Claim 40

An apparatus according to claim 29 or 33, wherein when the recording material passes between said carrying member and said contacting member, the recording material is electrostatically attracted onto said carrying member.

Claim 41

An apparatus according to claim 29, wherein said contacting member is in the form of roller.

Claim 42

An apparatus according to claim 36, wherein said carrying member is in the form of a dielectric sheet.

Claim 43

An image forming apparatus, comprising: a recording material carrying member for carrying a recording material; image forming means for forming a toner image on the recording material carried on said recording material carrying member; attracting means for electrostatically attracting the recording material to said recording material carrying member, said attracting means having an attracting member on a recording material carrying side of said recording material carrying member; and control means for controlling an image forming condition of said image forming means in accordance with a current through said attracting means when the recording material passes between said recording material carrying member and said contacting member.

Claim 44

An image forming apparatus, comprising: a recording material carrying member for carrying a recording material; image forming means for forming a toner image on the recording material carried on said recording material carrying member; attracting means for electrostatically attracting the recording material to said recording material carrying member, said attracting means having an attracting member on a recording material carrying side of said recording material carrying member; and control means for controlling an image forming condition of said image forming means in accordance with a current through said attracting means when the recording material passes between said recording material carrying member and said contacting member.

Claim 45

An apparatus according to claim 39, wherein said image forming means includes an image bearing member and image transfer charging means for transferring the image from said image bearing member to the recording material, and said control means limits an output of said transfer charging means.

Claim 46

An apparatus according to claim 39, wherein said attracting means includes discharging means for applying electric charge to said recording material carrying member, said discharging means is disposed so as to interpose said carrying member with said attracting member, and said discharging means effects a discharging operation when the recording material passes between said carrying member and said attracting member.

Claim 47

An apparatus according to claim 40, wherein said toner image forming means includes means for transferring different color toner images superimposedly from said image bearing member onto the same transfer material carried on said carrying member.

Claim 48

An apparatus according to claim 42, wherein said apparatus is capable of forming a full-color toner image.

Claim 49

An apparatus according to claim 39, wherein said carrying member is in the form of a dielectric sheet.

Claim 50

An image forming apparatus, comprising: a recording material carrying member for carrying a recording material; image forming means for forming a toner image on the recording material carried on said recording material carrying member; attracting means for electrostatically attracting the recording material to said recording material carrying member, said attracting means having an attracting member on a recording material carrying side of said recording material carrying member; constant current control means for maintaining a constant current supply to said attracting member as the recording material passes between said recording material carrying member and said attracting member; and a second control means for controlling an image forming condition of said image forming means in accordance with a voltage during constant current control by said constant current control means.

Claim 51

An image forming apparatus, comprising: a recording material carrying member for carrying a recording material; image forming means for forming a toner image on the recording material carried on said recording material carrying member; attracting means for electrostatically attracting the recording material to said recording material carrying member, said attracting means having an attracting member on a recording material carrying side of said recording material carrying member; constant current control means for maintaining a constant current supply to said attracting member as the recording material passes between said recording material carrying member and said attracting member; and a second control means for controlling an image forming condition of said image forming means in accordance with a voltage during constant current control by said constant current control means.

Claim 52

An apparatus according to claim 45, wherein said image forming means includes an image bearing member and image transfer charging means for transferring the image from said image bearing member to the recording material, and said second control means controls an output of said transfer charging means.

Claim 53

An apparatus according to claim 45, wherein said second control means controls the image forming condition of said image forming means in accordance with a voltage of said attracting member during the constant current control operation of said constant current control means.

Claim 54

An apparatus according to claim 45, wherein said attracting means includes discharging means for applying electric charge to said recording material carrying member, said discharging means is disposed such that said carrying member is interposed with said attracting member and said discharging means, and said discharging means effects a discharging operation when the recording material passes between said carrying member and said attracting member.

Claim 55

An apparatus according to claim 46, wherein said toner image forming means includes means for transferring different color toner images superimposedly from said image bearing member onto the same transfer material carried on said carrying member.

Claim 56

An apparatus according to claim 49, wherein said apparatus is capable of forming a full-color toner image.

Claim 57

An apparatus according to claim 45, wherein said carrying member is in the form of a dielectric sheet.