US 4,190,348 A · Lead edge transfer switching

Abstract

In an electrostatographic copying apparatus in which the imaging material is transferred to the copy member by electrical transfer members which leave electrostatic charges on the copy member resisting stripping of the copy member from the original image support surface, and in which a detacking corona generator is provided to partially neutralize those charges before the stripping of the lead edge of the copy member. There is provided an automatic switching system to apply a non-uniform increased transfer charge to the lead edge area of each copy member in comparison to the body of the copy prior to the detacking to improve the effective image transfer to the lead edge area of the copy after stripping. This is preferably provided by a transient over-shoot in the ouptut voltage of a constant current power supply for the transfer members for the lead edge.

Claims14

Dependent claims

In an electrostatographic copying apparatus in which imaging material is transferred from an image support surface to a moving copy member by electrical transfer means including an electrical power supply, which transfer means applies electrostatic fields for said transfer of the imaging material and deposits electrostatic charges on the copy member which electrostatically resist the stripping of the copy member from said image support surface;

and in which copying apparatus detacking corona generating means are also provided for at least partially neutralizing said charges deposited on the copy member by said transfer means so as to assist in the stripping of the lead edge of the copy member from said image support surface;
the improvement comprising:
transfer switching means for applying a non-uniform increased transfer charge to the lead edge area of a copy member to provide a substantially increased electrostatic transfer field to the lead edge area of the copy member in proportion to the remainder of the copy member, prior to the copy member being subjected to said detacking corona generating means, to improve said transfer of said imaging material to the lead edge area of said copy member.

In the method of electrostatographic copying in which imaging material is transferred from an image support surface to a moving copy member by electrical transfer means including an electrical power supply, which transfer means applies electrostatic fields for said transfer of the imaging material and deposits electrostatic charges on the copy member which electrostatically resist the stripping of the copy member from said image support surface;

and in which copying method detacking corona generating means are also provided for at least partially neutralizing said charges deposited on the copy member by said transfer means so as to assist in the stripping of the lead edge of the copy member from said image support surface;
the improvement comprising:
applying a non-uniform increased transfer charge to the lead edge area of a copy member to provide a substantially increased electrostatic transfer field to the lead edge area of the copy member in proportion to the remainder of the copy member, prior to the copy member being subjected to said detacking corona generating means, to improve said transfer of said imaging material to said lead edge area of said copy member.

Dependencies are inferred from the claim text.

Lead edge transfer switching

Life of this patent

Lead edge transfer switching

Life of this patent

Abstract

Claims14