US4937629A — Composite image recording apparatus

Claim 1

Independent Claim 218 words

An image forming method comprising: forming a first toner image by forming, on a latent image carrier, a first latent image corresponding to a first image, and by developing said first latent image, using a first toner charged to a first polarity, with a development process selected from normal and reverse development processes chosen to correspond to the polarity of said first toner; forming a second toner image by forming, on a latent image carrier, a second latent image corresponding to a second image, and by developing said second latent image, using a second toner charged to a second polarity opposite to said first polarity, with a development process selected from normal and reverse development processes chosen to correspond to the polarity of said second toner, while applying a developing bias VB2; simultaneously transferring said first and second toner images to a transfer medium during a transfer treatment process; and wherein said developing bias VB2 satisfies the following equations: |VT1-VB2|>|VH2-VB2| . . . (1) |VT1-VB2|>|VT1-VH2| . . . (2), wherein a surface potential of said first toner image in said step of forming a second toner image is VT1, a background potential in said step of forming a second toner image is VH2, and a developing bias in said step of forming a second toner image is VB2.

Claim 2

Dependent Claim 218 words

An image forming method comprising: forming a first toner image by forming, on a latent image carrier, a first latent image corresponding to a first image, and by developing said first latent image, using a first toner charged to a first polarity, with a development process selected from normal and reverse development processes chosen to correspond to the polarity of said first toner; forming a second toner image by forming, on a latent image carrier, a second latent image corresponding to a second image, and by developing said second latent image, using a second toner charged to a second polarity opposite to said first polarity, with a development process selected from normal and reverse development processes chosen to correspond to the polarity of said second toner, while applying a developing bias VB2; simultaneously transferring said first and second toner images to a transfer medium during a transfer treatment process; and wherein said developing bias VB2 satisfies the following equations: |VT1-VB2|>|VH2-VB2| . . . (1) |VT1-VB2|>|VT1-VH2| . . . (2), wherein a surface potential of said first toner image in said step of forming a second toner image is VT1, a background potential in said step of forming a second toner image is VH2, and a developing bias in said step of forming a second toner image is VB2.

Claim 3

Dependent Claim 138 words

The image forming method of claim 1, wherein; said step of forming a first toner image includes uniformly charging a photosensitive material of a latent image carrier, exposing a first image area to light so as to obtain a first negative image and reversely developing said exposed portion using a first toner which is charged to the same polarity as the charged polarity of the photosensitive material; said step of forming a second toner image includes exposing a background portion, except a second image area, to light at a level weaker than a first exposure level so as to obtain a second positive image, and normally developing an unexposed portion by a second toner which is charged to a polarity different from said photosensitive material; and simultaneously transferring said first and second toner images to said transfer medium.

Claim 4

Dependent Claim 153 words

The image forming method of claim 1, wherein; said step of forming a first toner image includes uniformly charging a photosensitive material of said latent image holder, exposing an area outside a first image area to light to obtain a first positive image, and normally developing an unexposed portion using a first toner which is charged to a polarity opposite to the charged polarity of said photosensitive material; said step of forming a second toner image is formed by recharging said photosensitive material to a lower level in absolute value than the potential of said first toner image without changing the polarity of said first toner image, exposing a second image and reversely developing said exposed portion of said second image by a second toner which is charged to the same polarity as the charged polarity of said photosensitive material; and simultaneously transferring said first and second toner images to said transfer medium.

Claim 5

Dependent Claim 209 words

An image forming apparatus comprising: a latent image carrier; a first latent image forming means for forming a first latent image corresponding to a first image and which is an object of one selected from normal development and reverse development on said latent image holder; a first developing means for developing said first latent image by a first toner charged to one polarity so as to form a first toner image; a second latent image forming means for forming a second latent image corresponding to a second image and which is an object of another selected from reverse development and normal development on said latent image holder so that said second latent image has a background potential VH2 which is the intermediate potential of the potential of the image area of said second latent image and the surface potential VT1 of said first toner image; a second developing means to which a developing bias VB2 satisfying the equations |VT1-VB2|>|VH1-VB2| and |VT1-VB2|>|VT1-VH2| is applied and which develops said second latent image by a second toner charged to a second polarity by magnetic brush development so as to form a second toner image; and a transfer treatment means for simultaneously transferring said first and second toner images to a transfer medium.

Claim 6

Dependent Claim 209 words

An image forming apparatus comprising: a latent image carrier; a first latent image forming means for forming a first latent image corresponding to a first image and which is an object of one selected from normal development and reverse development on said latent image holder; a first developing means for developing said first latent image by a first toner charged to one polarity so as to form a first toner image; a second latent image forming means for forming a second latent image corresponding to a second image and which is an object of another selected from reverse development and normal development on said latent image holder so that said second latent image has a background potential VH2 which is the intermediate potential of the potential of the image area of said second latent image and the surface potential VT1 of said first toner image; a second developing means to which a developing bias VB2 satisfying the equations |VT1-VB2|>|VH1-VB2| and |VT1-VB2|>|VT1-VH2| is applied and which develops said second latent image by a second toner charged to a second polarity by magnetic brush development so as to form a second toner image; and a transfer treatment means for simultaneously transferring said first and second toner images to a transfer medium.

Claim 7

Dependent Claim 43 words

The image forming apparatus according of claim 4, wherein said second developing means includes a developer holder comprising a nonmagnetic rotary sleeve with a magnet roll fixed therein, said magnet roll having a repulsion magnetic pole in correspondence with a developing nip range.

Claim 8

Dependent Claim 57 words

The image forming apparatus of claim 4, wherein said second developing means includes a developer holder comprising a nonmagnetic fixed sleeve with a magnet roll rotatably disposed therein so as to satisfy the equation: 0.5≦V.sub.DEVE /Vp≦2.0 where the moving speed of said developer is V DEVE and the rotational speed of said latent image carrier is Vp.

Claim 9

Dependent Claim 67 words

The image forming apparatus of claim 4, wherein said transfer treatment means includes: a pre-transfer treatment means for arranging said first and second toner images in the same polarity; and a transfer means for charging said transfer medium to a polarity opposite to the charged polarity of said toner images arranged by said pre-transfer treatment means, and for electrostatically transferring said toner images to said transfer medium.

Claim 10

Dependent Claim 46 words

The image forming apparatus of claim 7, wherein said pre-transfer treatment means includes: a uniform exposure means for uniformly exposing the surface of a photosensitive material of said latent image holder; and a charging means for discharging during or after exposure by said uniform exposure means.

Claim 11

Dependent Claim 37 words

The image forming apparatus of claim 7, wherein an AC voltage to which is superposed a DC component having the same polarity as the charged polarity of said latent image holder is applied to said charging means.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-06-25	1993-12-25	1994-06-26	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-06-25	1997-12-25	1998-06-26	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-06-25	2001-12-25	2002-06-26	$7700.00	Window Closed / Lapsed

Composite image recording apparatus

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