Image development amplification

Claim 2

Apparatus for developing a latent electrostatic image comprising: an electrically conductive plate; an electrically insulative substrate mounted on said plate, said insulative substrate adapted to have a latent electrostatic image formed on an exposed surface thereof and an opposite polarity mirror image charge induced on the other surface thereof which mirror image charge tends to degrade and interfere with development of the latent image; a capacitance; and means for connecting said capacitance between said conductive plate and a potential different from that of said conductive plate during development of said image thereby to accept and dissipate the mirror image charge from said other surface of said substrate and reduce said induced charge whereby the development of the latent image is enhanced.

Claim 3

The apparatus of claim 1 wherein said capacitance is connected between said conductive plate and ground.

Claim 4

The apparatus of claim 1 wherein said capacitance is connected to an electrically conductive surface spaced from said conductive plate.

Claim 5

The apparatus of claim 3 which further includes means for selectively discharging said capacitance.

Claim 6

The apparatus of claim 4 which further comprises means for distributing a cloud of electrostatically charged powder particles between the insulative substrate and said electrically conductive surface.

Claim 7

In an apparatus for the development of latent electrostatic images on a prescribed imaging surface of an electrically insulative substrate and including a prescribed development chamber adapted to contain a prescribed array of charged developer particles, this chamber including at least one electrically conductive developer surface disposed operatively adjacent said array of developer particles, said image comprising a pattern of prescribed maximum total image charge and said developer particles being charged to a polarity opposite that of this image, the improvement therein comprising, in combination: substrate conductor means disposed adjacent the insulative substrate, in electrical ohmic contact with the side thereof opposite said imaging surface so as to accommodate the transfer thereto of a ''''mirror charge pattern'''' induced by the original image charge pattern; capacitance means electrically coupled between said substrate conductor means and at least one of said conductive developer surfaces and adapted to receive and store a total charge at least equal to said maximum total image charge contemplated at the operating potential; and capacitance discharged means adapted to selectively shunt said capacitance means thereby to remove the charge stored therein.

Claim 8

In an apparatus for the development of latent electrostatic images on a prescribed imaging surface of an electrically insulative substrate and including a prescribed development chamber adapted to contain a prescribed array of charged developer particles, this chamber including at least one electrically conductive developer surface disposed operatively adjacent said array of developer particles, said image comprising a pattern of prescribed maximum total image charge and said developer particles being charged to a polarity opposite that of this image, the improvement therein comprising, in combination: substrate conductor means disposed adjacent the insulative substrate, in electrical ohmic contact with the side thereof opposite said imaging surface so as to accommodate the transfer thereto of a ''''mirror charge pattern'''' induced by the original image charge pattern; capacitance means electrically coupled between said substrate conductor means and at least one of said conductive developer surfaces and adapted to receive and store a total charge at least equal to said maximum total image charge contemplated at the operating potential; and capacitance discharged means adapted to selectively shunt said capacitance means thereby to remove the charge stored therein.

Claim 9

Apparatus for developing a latent electrostatic image comprising: an electrically insulative substrate mounted on a conductive plate, said insulative substrate having a latent electrostatic image of a predetermined total charge formed on an exposed surface thereof and an opposite polarity induced charge on the other surface thereof; a development chamber having an interior conductive portion and adapted to have said substrate positioned thereon with the image bearing surface opposed to and spaced from said conductive portion; means for distributing a dispersion of electrostatically charged powder particles within said chamber between the insulative substrate and the conductive portion for development of said image; and means for enhancing the external field of said latent image, said means including a capacitance adapted to be interconnected between said conductive plate and said conductive portion of said chamber during development of said image thereby to accept charges from said other surface of said substrate and reduce said induced charge, whereby the density of the developed image is increased.

Claim 10

Apparatus for developing a latent electrostatic image comprising: an electrically insulative substrate mounted on a conductive plate, said insulative substrate having a latent electrostatic image of a predetermined total charge formed on an exposed surface thereof and an opposite polarity induced charge on the other surface thereof; a development chamber having an interior conductive portion and adapted to have said substrate positioned thereon with the image bearing surface opposed to and spaced from said conductive portion; means for distributing a dispersion of electrostatically charged powder particles within said chamber between the insulative substrate and the conductive portion for development of said image; and means for enhancing the external field of said latent image, said means including a capacitance adapted to be interconnected between said conductive plate and said conductive portion of said chamber during development of said image thereby to accept charges from said other surface of said substrate and reduce said induced charge, whereby the density of the developed image is increased.

Claim 11

Apparatus as set forth in claim 7 which further includes means for selectively discharging said capacitance.

Claim 12

Apparatus as set forth in claim 8 in which said capacitance is adapted to receive and store charges of a magnitude at least equal to the predetermined total image charge.

Claim 13

In an apparatus for developing a latent electrostatic image on an electrically insulative substrate mounted on an electrically conductive plate wherein development tends to be degraded and interfered with by a mirror image charge induced on the ''''back'''' surface of said substrate adjacent said plate, this substrate being adapted to have a latent electrostatic image formed on an exposed front surface thereof and an opposite polarity induced charge on the opposite back surface thereof, the improvement comprising, in combination: dissipation means adapted to dissipate the mirror image charges so induced on said back surface of the substrate to thereby enhance any electrostatic development field projected to the ''''front'''' side of said substrate adapted to receive the said image for development; this dissipation means including capacitive storage means and means for coupling said capacitive storage means between said plate and a potential different from that of said plate, at least during development of said image, to thereby accept the charges from said back surface of said substrate and reduce the induced charge there, thus enhancing said development.

Claim 14

In an apparatus for developing a latent electrostatic image on an electrically insulative substrate mounted on an electrically conductive plate wherein development tends to be degraded and interfered with by a mirror image charge induced on the ''''back'''' surface of said substrate adjacent said plate, this substrate being adapted to have a latent electrostatic image formed on an exposed front surface thereof and an opposite polarity induced charge on the opposite back surface thereof, the improvement comprising, in combination: dissipation means adapted to dissipate the mirror image charges so induced on said back surface of the substrate to thereby enhance any electrostatic development field projected to the ''''front'''' side of said substrate adapted to receive the said image for development; this dissipation means including capacitive storage means and means for coupling said capacitive storage means between said plate and a potential different from that of said plate, at least during development of said image, to thereby accept the charges from said back surface of said substrate and reduce the induced charge there, thus enhancing said development.

Claim 15

The apparatus of claim 10 wherein: said capacitance is connected between said conductive plate and ground.

Claim 16

The apparatus of claim 10 wherein: said capacitance is connected to an electrically conductive surface spaced from said conductive plate.

Claim 17

The apparatus of claim 10 which further includes means for selectively discharging said capacitance.

Claim 18

The apparatus of claim 13 which further comprises means for distributing a cloud of electrostatically charged powder particles between the insulative substrate and said electrically conductive surface.

Claim 19

The apparatus of claim 10 as arranged to form part of a powder cloud development chamber; this chamber including electrically conductive surfaces spaced from the conductive plate, and means for distributing a cloud of electrostatically charged toner particles between the insulative substrate and at least a portion of the conductive surfaces of the development chamber; and wherein said capacitive means is coupled between said conductive plate and said conductive chamber surfaces.

Claim 20

The combination as recited in claim 10 wherein is also included switch means for selectively coupling said capacitive means to said potential source when said mirror image charge is to be removed therefrom.