JP2001066902A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an image on a base body from a toner-grain image electrified to given polarity by using liquid developer. SOLUTION: This image forming device is constituted by including a hardening means 26 hardening a liquid toner image and eliminating liquid therefrom and an intermediate transfer member 40 receiving the toner image from an image supporting surface 16 after the toner image is hardened in order to transfer the toner image on the base body 42. Besides, the hardening means 26 is constituted by including a squeeze roller and at least one part of the squeeze roller is electrified and pressed to the image supporting surface. Then, at least one part of the squeeze roller is electrified to voltage whose polarity is identical to that of the toner image and which is higher than about 500 V.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image transfer technique and apparatus used for electrophotography.

[0002]

2. Description of the Related Art A liquid toner image is formed by changing the density of a colored solid substance of a developer on an indigo (deep blue) latent image supporting surface in accordance with an imaged pattern.
Developed. The change in density is correspondingly provided by an electric field pattern extending outwardly from the latent image support surface, the electric field pattern having different latent image and background voltages on the latent image support surface and the development plate or roller. And the voltage.

Generally, developed liquid toner images are not solid materials and are not homogeneous. Typically, liquid toner developers contain about 1.5% to 2% solids and developed images contain about 15% to 25% solids. The developed image has a higher density closer to the latent image support surface, and has a "fluffy" or loose coupling area at the furthest away from the latent image support surface.

[0004] To improve the transfer of a clearly developed image from the latent image bearing surface to the substrate, prior to transfer the colored solid material near the background area is substantially removed and developed. It is most desirable to increase the density of the colored solid material in the developed image, thereby ensuring that the developed image is compressed (compacted) and cured. The compression and curing of such a developed image increases the viscosity of the image and improves its ability to maintain image integrity under the stresses applied during image transfer. It is also desirable that excess liquid be removed from the latent image support surface prior to transfer.

As described in US Pat. No. 3,955,533, the prior art uses a reversing roller about 50 .mu.m from the latent image bearing surface to support the carrier beyond the image outer edge. It is known to shear off liquid and colored solid materials, thereby leaving a relatively clean area above the background.

[0006] The technology for removing the carrier liquid is meteorological (mete
ring). Another metering technique described in U.S. Pat. Nos. 3,767,300 and 3,741,643, which uses air knives, is not a particularly successful example. This is because the background is contaminated because the inversion layer of the background mixes with the surface layer of the carrier liquid.

In US Pat. No. 3,957,016, the use of a positively biased metering roller is proposed. In this case, the metering roller is maintained at an intermediate voltage between the image voltage and the background voltage to clean the background and to slightly compress the image.

[0008]

In the prior art, it is known to effect image transfer by bringing the image into contact with a substrate supported by a charged roller. If the image is not hardened before reaching the nip between the latent image support surface and the roller, the image will be crushed and flow. This is particularly acute when the substrate is a non-porous material, such as a plastic.

In the prior art, liquid toner images are generally transferred to a substrate by electrophoresis. This allows the charged image to pass from the latent image support surface through the carrier liquid under the influence of an electric field created by the high voltage applied to the substrate, which is of opposite polarity to the charge of the image forming particles. It moves to.

[0010] The voltage available for electrophoretic transfer, the electric field strength, is the electrical isolation that can occur at both the entrance and exit edges of the nip due to the minimum value of the Paschen curve being about 8 µm. Limited by the risk of destruction. Therefore, according to the Paschen curve, the voltage difference at the nip should be about 36 if damage to the image and damage to the latent image support surface due to electrical breakdown must be avoided.
It cannot exceed 0 volts.

[0011] Electrophoretic image compression of the image prior to transfer indicates the placement of a negatively biased squeegee roller (cleaning roller) after the metering roller, US Pat. No. 4,286. , 039. The squeegee roller operates both for image compression and for removing excess liquid. The voltage that can be applied to the squeegee roller is also limited by the risk of electrical breakdown. This dielectric breakdown problem is at least significant at the entrance of the squeegee roller. This is because the meniscus existing there increases the minimum effective gap. In the image area, the problem of dielectric breakdown becomes more severe. This is because an electric field formed by the squeegee roller and the latent image supporting surface is applied. This problem is most severe at the exit edge of the squeegee roller where there is substantially no meniscus.

In US Pat. No. 4,684,238, an unmetered image is first transferred to an intermediate transfer member and then has the opposite polarity to the charge of the toner particles forming the image. Is measured by a measuring roller to which a voltage of? No mention is made of the problem of electrical breakdown.

[0013]

SUMMARY OF THE INVENTION The present invention seeks to provide an improved apparatus for improving image transfer.

Thus, a preferred embodiment of the present invention provides an apparatus for improving liquid toner image transfer. The apparatus includes an image support surface, means for forming a liquid toner image on the image support surface, and a second surface arranged to move relative to the image support surface, the image support surface comprising: A second surface, wherein the surface and the area of the second surface are successively approached and then later separated from the approaching state, wherein the second surface is associated with at least a portion of at least one of the image bearing surface and the second surface. Potential applying means for applying an electric potential to the portion, and energizing the potential applying means to cure the image only when the at least one portion is placed at a predetermined position along the movement path. Biasing means.

Further in accordance with a preferred embodiment of the present invention, the potential application means includes a plurality of conductors associated with at least one of the image bearing surface and the second surface.

According to another preferred embodiment of the present invention, an image transfer device is provided. The apparatus includes an image support surface, an image compression surface disposed in operative engagement with the image support surface, and having at least one electrical conductor formed therein, and an engagement between the image compression surface and the image support surface. Biasing means for biasing at least one electrical conductor disposed therein in such a manner that a relatively high potential difference is generated between the image compression surface and the image bearing surface; Including.

According to a preferred embodiment of the present invention, the liquid toner image further includes an image area and a background area, and the apparatus removes the colored toner particles from the background area formed on the image bearing surface. Means and squeegee means for removing excess liquid from the liquid image after hardening and before transferring the image to the substrate.

Still further in accordance with a preferred embodiment of the present invention, the toner image includes charged toner particles, the second surface being a roller surface and moving in a direction opposite the image bearing surface.
The potential applying means applies the first potential to the first area of the second surface to clean the background, and the second area of the same polarity of the toner particles is applied to the second area of the second surface. An electric potential is applied to cure the liquid toner image on the image support surface.

Further in accordance with a preferred embodiment of the present invention, the apparatus further comprises a biasing means for biasing the electrical conductor to form a desired electric field at a desired location and to cure the image at that location. including.

Still further according to a preferred embodiment of the present invention, the second surface includes a rotating surface.

Still further according to a preferred embodiment of the present invention, the second surface includes a stationary surface, and the image bearing surface moves relative to the stationary surface.

In accordance with a preferred embodiment of the present invention, the apparatus further includes an intermediate transfer member for receiving, after curing, the liquid toner image from the image bearing surface and transferring the image to a substrate. .

According to a preferred embodiment, the liquid toner particle image further includes an image area and a background area, and the apparatus includes a removing means for removing the colored toner particles from the background area formed on the image bearing surface. Squeegee means for removing excess liquid from the liquid image after the liquid image has been hardened and before transfer to the substrate.

Still further in accordance with a preferred embodiment of the present invention, the energizing of the at least one electrical conductor is such that a desired electric field is created at a desired location to cure the image.

Additionally, in accordance with a preferred embodiment of the present invention, the apparatus includes an intermediate transfer member for receiving a liquid toner image from an image bearing surface after curing and transferring the image to a substrate. Make

In accordance with a preferred embodiment of the present invention, the liquid toner image on the image bearing surface further includes an image area and a background area, and the apparatus further includes means for dispersing the colored toner particles from the background area formed on the image bearing surface. Removal means for removing and squeegee means for removing excess liquid from the liquid image after curing the liquid image and prior to transfer to the substrate.

In addition, in accordance with a preferred embodiment of the present invention, the toner image includes charged toner particles, the second surface being the surface of a rotating roller and moving in a direction opposite to that of the image bearing surface. In addition, the potential applying means may be a first electrical conductor having a polarity opposite to the polarity of the toner particles with respect to at least one of the plurality of conductors.
To clean the background, and to apply a second potential having the same polarity as the polarity of the toner particles to the second conductor associated with at least one of the plurality of conductors, thereby forming a second potential on the image supporting surface. Means for curing the liquid toner image.

According to a preferred embodiment of the invention, furthermore, the second surface is a roller surface, which moves in a direction opposite to the movement of the image bearing surface so as to weigh excess liquid on the image bearing surface. Eggplant

Still further in accordance with a preferred embodiment of the present invention, the operative engagement includes an inlet area, an outlet area, and a third area therebetween, and the biasing means is associated only with the third area. You.

In addition, according to a preferred embodiment of the present invention, the first potential is of a polarity opposite to that of the toner particles.

According to a further preferred embodiment of the present invention, there is provided an apparatus for transferring an image. The apparatus includes an image support surface adapted to support a liquid toner image comprising an image area and a background area, means for curing a toner particle image in the image area, and an image support for the cured image. And an intermediate transfer member for receiving the image from the surface and transferring the image to the substrate.

In addition, in accordance with a preferred embodiment of the present invention, the apparatus removes excess liquid from the toner image after curing the image and before transferring the image to an intermediate transfer member. Squeegee means to perform

According to a preferred embodiment of the present invention, the apparatus further comprises means for removing excess liquid from the image bearing surface.

According to a preferred embodiment of the present invention, the curing means further comprises a curing roller which is maintained at a potential opposite to the potential of the image area of the image bearing surface but is not brought into contact with the image, The apparatus also includes removal means for removing colored toner particles from the background area and removal means for removing excess liquid from the image bearing surface.

In addition, in accordance with a preferred embodiment of the present invention, the stiffening means is a second surface adapted to move along the path of movement relative to the image bearing surface, wherein And a second surface adapted to continuously move and subsequently move away from the approaching state by a portion of the image supporting surface and the second surface, and at least one of the image supporting surface and the second surface. and potential applying means for applying a potential to the portion being associated to a portion, an image biases the potential applying means only when said at least one portion is location or is at predetermined positions along the movement path And a biasing means for causing the to cure.

According to a preferred embodiment of the present invention, the potential applying means further includes a plurality of conductors associated with at least one of the image bearing surface and the second surface.

Still further in accordance with a preferred embodiment of the present invention, the second surface is arranged for operative engagement with the image bearing surface and has at least one electrical conductor formed therein, and
The apparatus includes means for biasing at least one electrical conductor located therein relative to the engagement of the second surface with the image bearing surface;
As a result, a relatively high potential difference is generated between the position inside the second surface and the image supporting surface.

In addition, in accordance with a preferred embodiment of the present invention, the potential applying means applies a first potential of a first polarity to a first portion of the second surface, and applies a first potential of the second surface. 2nd part 2
And an applying means for applying the second potential of the same polarity similarly.

According to a preferred embodiment of the present invention, a toner image formed of a colored powder having a charge of a second polarity is provided on the image supporting surface, and the first potential of the first portion is applied to the background. And the second charge in the second portion cures the toner image on the image bearing surface.

According to a preferred embodiment of the present invention, furthermore, the second surface is a roller surface, which moves in a direction opposite to the movement of the image bearing surface to meter excess liquid on the image bearing surface. I will do it.

In addition, according to a preferred embodiment of the present invention, the second surface is a roller surface, which is moved in a direction opposite to the movement of the image bearing surface.

Furthermore, in accordance with a preferred embodiment of the present invention, the energizing of the electrical conductor creates a desired electric field at the desired location to cure the image.

In addition, in accordance with a preferred embodiment of the present invention, the means for stiffening the image includes a rotating surface in operative engagement with the image.

According to a preferred embodiment of the present invention, the means for curing the image further comprises a stationary surface, with which the image bearing surface moves relative to the stationary surface.

Still further in accordance with a preferred embodiment of the present invention, the stationary surface includes at least one electrical conductor, and the bias on the at least one electrical conductor creates a desired electric field at a precise location to create an image. Let it cure.

In addition, in accordance with a preferred embodiment of the present invention, the means for curing includes a squeegee roller maintained at a potential of opposite polarity to that of the image area portion of the image bearing surface, which compresses the image. At the same time, excess liquid is removed from the image.

According to yet another embodiment of the present invention, there is provided an apparatus for transferring an image. The apparatus has an image bearing surface disposed to support a liquid toner image including an image area and a background area, and at least one layer of an elastic material, the outer surface of the layer being disposed on the image bearing surface along a movement path. Means for curing the liquid toner particle image relatively moved with respect to the image support surface and the outer surface so that the image support surface and the outer surface are successively approached and then separated from each other in the image area; A potential applying means for applying a potential to at least a part of the at least one part to apply a voltage between both surfaces when the at least one part is continuously approached to the image supporting surface; and And an intermediate transfer member for receiving the toner image from the surface and transferring the image to a substrate.

In accordance with yet another preferred embodiment of the present invention, there is provided a method of forming an image. The method includes the steps of forming a liquid toner image on an image supporting surface, curing the liquid toner image, transferring the cured image to an intermediate member, and subsequently transferring the image to a substrate as a final member. Transferring.

According to a preferred embodiment of the invention, furthermore, said at least one layer of elastic material comprises at least two layers, and a potential applying means is arranged between these two layers.

Still further in accordance with a preferred embodiment of the present invention, the stationary surface engages the image bearing surface at the entrance region, the exit region, and a third region therebetween, and the biasing device is a third region.
Related only to the region of

The approach can include contact engagement and non-contact engagement.

In addition, according to a preferred embodiment of the present invention, the second surface is a stationary surface, relative to which the image bearing surface is moved.

According to a preferred embodiment of the present invention, there is also provided an image transfer device. The apparatus includes an image support surface including an image area and a background area arranged to support a liquid toner image, a unit for curing the toner image in the image area, and a toner unit disposed apart from the curing unit. Squeegee means for removing excess liquid from the toner image after the image has been cured and before being transferred to the substrate.

Further in accordance with a preferred embodiment of the present invention, the liquid toner particle image includes charged toner particles, and the apparatus further includes a removing means for removing the colored toner particles from the background area; A cleaning roller and means for curing including a curing roller maintained at a positive and negative potential opposite to the positive and negative charges of the charged toner particles.

According to a preferred embodiment of the present invention, furthermore, the means for curing is a second surface arranged to move along the movement path relative to the image bearing surface, whereby A second surface adapted to continuously move away from the approaching state and a portion of the image supporting surface and the second surface, and at least one of the image supporting surface and the second surface; A potential applying means associated with at least one of the ones and adapted to apply a potential to the at least a part, and a potential applying means only when the at least a part is located at a predetermined position along a moving path. Biasing means for biasing.

In addition, in accordance with a preferred embodiment of the present invention, the potential application means includes a plurality of conductors associated with at least one of the image bearing surface and the second surface.

According to a preferred embodiment of the present invention, the means for curing further comprises an image compression surface arranged in operative engagement with the image bearing surface, the image compression surface comprising at least one conductive material. Energizing the compression surface and at least one of the electrical conductors located therein in relation to the engagement of the image compression surface and the image bearing surface to provide a relatively high voltage difference between the image compression surface and the image bearing surface. Biasing means for causing

According to a preferred embodiment of the present invention, the electric potential applying means further comprises a first portion on the second surface with respect to the first portion.
Means for applying a first potential of a second polarity and similarly applying a second potential of a second polarity to a second portion of the second surface.

In addition, in accordance with a preferred embodiment of the present invention, a liquid toner image formed by a colored powder having a second polarity charge is formed on the image bearing surface, and the first portion of the first portion has The charge cleans the background and the second part of the second
Charge hardens the toner image on the image bearing surface.

According to a preferred embodiment of the present invention, the second surface is a roller surface, and the second surface moves in a direction opposite to the movement of the image supporting surface, so that the excess liquid on the image supporting surface is removed. Weigh.

In addition, in accordance with a preferred embodiment of the present invention, the biasing of the electrical conductor causes the desired electric field to be created at the desired location to cure the image.

According to a preferred embodiment of the present invention, the means for curing further comprises a rotating surface.

In addition, in accordance with a preferred embodiment of the present invention, the image compression surface includes a stationary surface with which the image bearing surface moves.

According to a preferred embodiment of the present invention, the second surface is a roller surface, which moves in a direction opposite to the movement of the image supporting surface to measure excess liquid on the image supporting surface. I do.

Further in accordance with a preferred embodiment of the present invention, the apparatus further includes an intermediate transfer member for receiving the toner image from the image bearing surface after curing and transferring the image to a substrate.

In addition, in accordance with a preferred embodiment of the present invention, the operative engagement is included in the inlet area, the outlet area, and a third area therebetween, and the biasing means is only associated with the third area. Is done.

According to another preferred embodiment of the present invention, there is provided an apparatus for transferring an image. The device includes an image support surface and an image receiving member. The image receiving member has at least one layer made of an elastic material forming an outer image receiving surface arranged to move relatively along a movement path,
As a result, the areas of the image support surface and the image receiving surface are continuously approached to perform image transfer between them, and are continuously moved away from the approach state following the image transfer. The apparatus also includes a potential applying means accommodated in at least a part of the outer elastic layer, and applies an electric potential between at least a part of the outer elastic layer and the image supporting surface. Still further, the apparatus energizes the potential applying means only when the at least a part is located at a predetermined position along the movement path, so as to perform desired image transfer improvement. including.

According to a preferred embodiment of the present invention, the potential applying means includes a plurality of conductors.

According to a preferred embodiment of the present invention, the voltage applying means further includes an applying means for applying a potential having a first polarity opposite to the polarity of the charge of the image powder.

In addition, in accordance with a preferred embodiment of the present invention, the potential application means only applies the first potential to the portion when the at least a portion is located at a first predetermined position.
And applying means for applying the second potential to the part only when the part is located at the second position close to the first predetermined position.

According to a preferred embodiment of the present invention, furthermore, the potential applying means applies a first potential to at least a first portion of one surface, and applies a first potential to at least one surface adjacent to the first portion. And means for applying a second potential to the second portion.

According to a preferred embodiment of the present invention, furthermore, the electric potential applying means is provided on the first portion of at least one surface when the first portion is located at the predetermined first position. Applying a first potential and applying a second potential to the first portion when the first portion is located at a predetermined second position adjacent to the first position; and ,
Applying a second potential to the second portion when the second portion is located at the second predetermined position; and applying the second potential to the second portion when the second portion is located at the first position. First in part 2
And an applying means for applying the potential.

In addition, according to a preferred embodiment of the present invention, the potential applying means includes a first portion having a predetermined first portion.
The first position of at least one surface when the first position
Means for applying a first potential to the second portion and applying a second potential to the second portion on at least one surface when the second portion is located at a predetermined second position. And at the same time, applying a second potential to the first portion when the first portion is located at a predetermined second position, and applying a second potential to the first portion when the third portion is located at the first position. Means for applying a first potential to the third portion.

Further, according to a preferred embodiment of the present invention, the first and second potentials are of opposite polarity.

In addition, according to a preferred embodiment of the present invention, the plurality of conductors include a plurality of conductors, including first and second conductor arrays disposed on the image receiving surface, and are electrically connected. First biasing means for selectively biasing at least one conductor of the first array to apply a desired potential to a predetermined first location; and Second energizing means for selectively energizing at least one conductor of the two arrays to heat a desired image receiving surface at a predetermined second position.

According to a preferred embodiment of the present invention, the apparatus further comprises a removing means for removing excess liquid from the image bearing surface.

According to the preferred embodiment of the present invention, the potential applying means forms a desired electric field at a desired position to perform image transfer by electrophoresis.

In addition, in accordance with a preferred embodiment of the present invention, the apparatus includes transfer means for subsequently transferring an image from the image receiving member, and energizes at least one conductor of the second array. This provides the desired resistance heating to heat the image before subsequent transfer.

According to a preferred embodiment of the present invention, further, the image bearing surface is arranged to support a liquid toner image comprising an image area and a background area, and the apparatus comprises an image bearing surface for supporting the colored toner particles. And removing means for removing from the background area of the surface.

According to a preferred embodiment of the present invention, the removing means further comprises a roller having a potential intermediate between the image area and the background area.

In addition, according to a preferred embodiment of the present invention, the potential applying means applies a potential of the first polarity, which is the same as the charge of the image powder, to at least one conductor in the first region. And applying means for applying a potential of a second polarity opposite to the polarity of the charge of the image powder to at least one conductor in a second area adjacent to the first area, Image transfer to the image receiving member is performed in the area, and the image is cured in the second area.

According to the preferred embodiment of the present invention, furthermore, the first and second conductors having a plurality of conductors arranged on the image receiving surface are provided.
Wherein the electrical biasing means selectively biases at least one conductor of the first array to apply a desired potential to a given first location on the image receiving surface. And a second biasing means for selectively biasing at least one conductor of the second array to effect a desired heating of the image receiving surface at a second given position. Means.

In addition, in accordance with a preferred embodiment of the present invention, the apparatus includes a second transfer means for transferring an image from the image receiving surface to the substrate.

According to yet another preferred embodiment of the present invention, there is provided an apparatus for transferring an image. In this apparatus, the image supporting surface is a second image receiving surface that is relatively moved along a movement path, and the image supporting surface and the image receiving surface area perform image transfer between the two. An image receiving surface which is continuously approached and which is adapted to be continuously moved away from the close state after image transfer between the two, and associated with at least a part of at least one of the image supporting surface and the image receiving surface; A potential applying means for simultaneously applying a first potential to at least a part of one surface and a second potential to a second part adjacent to the at least one surface; and energizing the potential applying means. Applying a first potential only when the first portion is located at a predetermined position along the movement path, thereby providing a desired image transfer improvement along the first portion. Simultaneously cure the image along the adjacent second part So that including the eggplant biasing means.

According to a preferred embodiment of the present invention, there is further provided an apparatus for transferring an image of a liquid toner image. The apparatus includes an image support surface configured to carry a liquid toner image and an electrically insulating carrier liquid, and an image receiving surface arranged to be relatively movable along a movement path,
The area of the image support surface and the image receiving surface are continuously approached so as to perform image transfer between the two in the image transfer area, and are continuously moved away from the close state after the image transfer between the two,
A liquid toner image and a carrier liquid associated with at least a portion of the image receiving surface and the image receiving surface adapted to fill a first portion between the image supporting surface and the image receiving surface; A potential applying means for applying a potential to at least a part thereof, wherein the at least a part is a first
And a biasing means for biasing the potential applying means when completely positioned at the portion.

According to a preferred embodiment of the invention, furthermore, the at least one layer made of an elastic material comprises at least two layers of an elastic material, and the potential applying means is arranged between the two layers.

According to a preferred embodiment of the present invention, there is provided an image transfer device. The image receiving member includes an image supporting surface and an outer layer forming an outer image receiving surface, and is adapted to be relatively moved along a movement path, wherein the image receiving surface and the image supporting surface are both provided. The image receiving member, which is continuously approached so as to perform image transfer between the two and moves continuously away from the close state after the image transfer between the two, and an outer layer including a plurality of conductors; A housed potential applying means, an energizing means for energizing the potential applying means to improve image transfer from the image support surface to the image receiving surface, and a transfer for transferring the image to a base which is a final support member Means.

According to a preferred embodiment of the present invention, the plurality of conductors further include first and second conductor arrays, and the biasing means biases at least one conductor of the first array. Urging means for applying a desired potential to a predetermined first position and a second urging means for urging at least one conductor of the second array to perform desired heating of the image receiving surface Biasing means.

In accordance with yet another preferred embodiment of the present invention, there is provided an image transfer device. The apparatus is an image receiving member including an image support surface and an outer layer forming an outer image receiving surface, the image receiving member being adapted to be relatively moved along a movement path, the area of the image receiving surface and the image support surface. The image receiving member is continuously approached so as to perform image transfer between the two, and is moved to be continuously separated after the image transfer between the two,
A potential associated with one of the image support surface and the image receiving surface for applying a first potential to a first portion of at least one surface and simultaneously applying a second potential to a second portion of the at least one surface; Applying means for applying the first potential only when the first portion is located at a predetermined position along the movement path, and performing desired image transfer improvement along the first portion At the same time, biasing means adapted to cure the image along the adjacent second portion.

Further according to a preferred embodiment of the present invention, the outer layer comprises an elastic outer layer having at least one layer of an elastic material.

According to a preferred embodiment of the present invention, the potential applying means is further housed inside the outer layer.

In addition, according to a preferred embodiment of the present invention, the potential application means includes a plurality of conductors.

Further, according to a preferred embodiment of the present invention, the first and second potentials are of opposite polarity.

Still further in accordance with a preferred embodiment of the present invention, the image bearing surface is arranged to support a liquid toner image comprising an image area and a background area, and the apparatus is formed on the image bearing surface. Removing means for removing colored toner particles from the background area.

In addition, in accordance with a preferred embodiment of the present invention, the image is a liquid toner image comprising a carrier liquid and charged toner particles, and the first potential is of the same polarity as the toner particles. And the second potential has a polarity opposite to the polarity of the toner particles.

According to a preferred embodiment of the present invention, the apparatus further comprises a second transfer means for transferring an image from the image receiving surface to the substrate.

According to a preferred embodiment of the present invention, furthermore, at least one layer of the elastic material comprises at least two layers of the elastic material, and the potential applying means is arranged between these two layers.

[0098] In addition, according to a preferred embodiment of the present invention, the access includes a contact engagement.

The present invention will be more fully understood and appreciated by the following detailed description in conjunction with the drawings.

[0100]

1, there is shown an electrophotographic apparatus constructed and operated in accordance with a preferred embodiment of the present invention. This and other embodiments of the invention are described for the case of a liquid toner device using a negatively charged powder and a positively charged photoconductive photoconductor. The polarity of the applied voltage is opposite for positively charged toner particles.

In a preferred embodiment of the present invention, US Pat. No. 4,7,749, incorporated herein by reference.
Although the toner of Example 1 of No. 94,651 can be used, various types of liquid toners are useful in the practice of the present invention.

As in a conventional electrophotographic apparatus, the apparatus of FIG. The drum is arranged to rotate about axis 12 in the direction indicated generally by arrow 14. The drum 10 is formed with a cylindrical photoconductive surface 16.

The corona discharge device 18 is operated to charge the photoconductive surface 16 uniformly and uniformly with the positive charge. The photoconductive surface 16 charged by the continuous rotation of the drum 10 is brought into a state of receiving an image with the exposure unit. This unit includes a lens 20 to form a desired image on the charged photoconductive surface 16 to selectively neutralize the photoconductive surface to form an electrostatic latent image. Eggplant

As the drum 10 continues to rotate, the charged photoconductive surface 16 carrying the electrostatic latent image is carried to the developing unit 22. The development unit includes a development electrode 24 that operates to apply liquid toner particles to develop the electrostatic latent image.

According to a preferred embodiment of the present invention, after application of the toner particles, the photoconductive surface 16 passes through a generally positively charged rotating roller 26. This roller is preferably rotated in the direction of arrow 28. Generally, the distance between the roller 26 and the photoconductive surface 16 is about 50 μm.

The electric charge of the roller 25 is preferably set to an intermediate value between the voltage of the electrostatic latent image and the voltage of the background area of the photoconductive surface. A typical voltage is 200 V at the roller 26 and 50 V at the background area, and the area of the electrostatic latent image is 100 V.
It is set to 0V.

The roller 26 can be rotated in the direction opposite to the direction shown by the arrow 28 and can function as a metering roller to reduce the thickness of the liquid on the photoconductive surface 16.

[0108] Alternatively, the metering function can be omitted at this stage and performed downstream by suitable techniques.

In any case, the liquid that has passed through the roller 26 has relatively little colored powder except in the area of the electrostatic latent image.

[0110] Downstream of the roller 26, a roller 30 for curing is preferably provided. The curing roller 30 is disclosed in U.S. Pat. No. 3,959,574.
No. 3,863,603, and the like, and is preferably formed of an elastic polymeric material, such as the conductive elastic polymeric material described in either or both. It is also preferred that the photoconductive surface 16 be maintained in a non-contact relationship.

According to one embodiment of the present invention, roller 30 is slightly pressed against photoconductive surface 16 in a manner such as by spring mounting (not shown). Photoconductive surface 1
The rotation of 6 exerts hydrodynamic force on the roller 30,
This force pushes the roller slightly away from the photoconductive surface 16 so as to form a gap, typically 15 μm from the photoconductive surface.

According to another embodiment of the present invention, the roller 3
0 can be fixedly formed with a gap from the photoconductive surface 16. In this case, the roller 30 is positioned at a distance of about 50 μm from the photoconductive surface in consideration of the unevenness of the surface. The surface of the roller 30 typically moves in the same direction as the photoconductive surface, such that it does not substantially remove liquid from the image. Roller 30 and photoconductive surface 16
The nip during this is preferably kept wet to minimize electrical discharge problems. Various configurations of the curing roller that reduce the problem of electrical discharge are described below.

In an embodiment of the present invention, US Pat.
A biased squeegee as described in 86,039 is used as roller 30. hundreds~
Negative voltages of 2000 volts are used and dielectric breakdown is often experienced. Roller 30 is negatively charged, similarly to the charge of the colored toner particles, and is charged to a potential of at least several hundred to 2000 volts, thereby repelling the similarly charged colored toner particles and causing the toner particles to become photoconductive. The image area of the active surface 16 is brought closer and closer, thereby compressing and hardening the image.

An intermediate transfer member 40 is provided downstream of the curing roller 30. The intermediate transfer member rotates in a direction opposite to the photoconductive surface 16 as indicated by an arrow 41, receives a toner image from the photoconductive surface, and receives the toner image from a receiving substrate such as paper. 42
It works to transfer to.

Various types of intermediate transfer members are known, for example, related U.S. patents entitled Methods and Apparatus for Imaging Using Intermediate Transfer Members, filed January 4, 1989. Request serial number 4,684,2
No. 38. The disclosure of which is incorporated herein by reference. The structure of the intermediate transfer member which is particularly advantageous according to the present invention is described in detail below.

The image transfer to the intermediate transfer member 40 can be performed by other methods known in the art. However, the voltage of the intermediate transfer member 40 is opposite to that of the charged powder. As described above. Subsequent image transfer to the substrate 42 is preferably assisted by heat and pressure, and pressure is provided by the backing roller 43, although other methods known in the art can be used.

If the negatively biased squeegee roller at high negative voltage of US Pat. No. 4,286,039 is used as roller 30,
It is noted that the positive voltage of the intermediate transfer member required to transfer an image is typically sharply reduced from 1000 volts or more to a voltage of about 500 volts. This reduction is caused by the discharge of electric charges in the image area on the image supporting surface and the charging in the background area on the image supporting surface.

Following transfer of the toner image to the intermediate transfer member, photoconductive surface 16 engages a cleaning roller 50 which typically rotates in the direction indicated by arrow 52. The surface then moves in a direction opposite to the direction of movement of the adjacent photoconductive surface 16 in operative engagement. This cleaning roller 50
Is cleaned by rubbing the surface 16. Cleaning material, such as toner, is supplied to cleaning roller 50 through conduit 54. A wiper blade 56 completes the cleaning of the photoconductive surface. Charge remaining on photoconductive surface 16 is removed by pouring light from lamp 58 onto the photoconductive surface.

Referring to FIG. 2, there is shown an electrophotographic imaging apparatus constructed and operative in accordance with a preferred embodiment of the present invention. The device of FIG. 2 uses a number of common components with the device of FIG. These components are denoted by the same reference numerals and will not be described again here for the sake of simplicity.

The embodiment of FIG. 2 is different from the embodiment of FIG. 1 in that the roller 30 for curing is omitted, and a belt-type intermediate transfer member 70 is used instead of the roller type. Are different. Belt-type intermediate transfer members are well known in the art and are described in particular in U.S. Patent Nos. 3,893,761; 4,684,238 and 4,690,539. I have. The disclosure of which is incorporated herein by reference.

The belt-type intermediate transfer member can be used in the apparatus shown in FIG.
It will be appreciated that this embodiment can be omitted from and added to the embodiment of FIG.

The intermediate transfer member 70 is preferably charged so that an image is transferred from the photoconductive surface 16 by electrophoresis. Photoconductive surface 16 and intermediate transfer member 70
By increasing the potential difference between and the electrophoretic efficiency can be increased within given limits. However, the increase in potential difference between photoconductive surface 16 and intermediate transfer member 70 is limited by the risk of electrical breakdown. The risk of such dielectric breakdown increases with an increase in the potential difference.

The relationship between the minimum voltage at which breakdown occurs across the gap and the gap size is given by the well-known Paschen curve. In the case of air, the minimum breakdown voltage for the air gap between the two surfaces occurs with a voltage difference of typically about 360 volts for an air gap of about 8 μm. This breakdown voltage relates to air gaps that are larger or smaller than the indicated air gap, and increases significantly when liquids such as dielectric isomers and liquid developers are present in the air gap.

According to a preferred embodiment of the present invention, means are provided for significantly reducing or eliminating the occurrence of electrical breakdown near photoconductive surface 16. Such breakdown can damage the photoconductive surface and / or the image. In this regard, please refer to FIGS. 3A and 3B. These drawings conceptually show an intermediate transfer member 40 having a limited charged area or a plurality of charged areas.

FIG. 3A conceptually illustrates an intermediate transfer member 40 which has conductive strips disposed thereon, at any given time, and at any given time of the intermediate transfer member. Even in the rotating state, only the angularly bounded portion of the intermediate transfer member is urged to a substantially higher voltage value to form a large potential difference with the photoconductive surface 16. Make

In the illustrated embodiment, the biased portion indicated by reference numeral 60 is bounded by an adjacent radial position 61;
Also, a nip 6 between the intermediate transfer member and the photoconductive surface 16
The area is selected so as to substantially correspond to the second area. 1 of the present invention
According to one embodiment, the energized portion corresponds to this region full of liquid, thus substantially reducing or eliminating the discharge. According to a more generalized concept of the present invention, this biased portion need not be limited to the area filled with liquid, but taking into account the properties of the material placed in the cavity, Is limited to a region where there is no space such that the breakdown voltage is smaller than the potential difference between the energized portion and the photoconductive surface 16. More generally, small breakdowns are acceptable.

In the embodiment of FIG. 3A, even if a small potential difference or a large potential difference can be used, it is possible to use one potential across the gap.
A potential difference between 2,000 volts and 2000 volts must be maintained for maximum results.

FIG. 3B shows a further development of the structure shown in FIG. 3A. Here, the voltage is supplied to the conductor in the intermediate transfer member 40, and as shown in FIG.
At 4 and 66, two different potential differences are applied to the surface of the intermediate transfer member.

This arrangement provides an intermediate transfer member 40 that serves the dual function of curing the image prior to transfer and then transferring the cured image from photoconductive surface 16 to intermediate transfer member 40. Useful on

In such a structure, the colored powder is negatively charged as usual, the image forming area of the photoconductive surface is positively charged, and the photoconductive surface 16 and the intermediate transfer member 40 are charged. When the rotation direction of the part 6 is the direction shown in FIG.
4 is biased to a negative potential, typically between -200 volts and
Energized to 2000 volts, which compresses or cures the image by pressing the colored powder toward the image area of the photoconductive surface. On the other hand, the portion 66 is biased to a positive potential, typically between +300 volts and +2500 volts, so that the intermediate transfer member 40 in the region 66 through the solvent present in the meniscus 68 from the photoconductive surface 16.
The image is absorbed upward by electrophoresis. Part 66
A lower positive voltage can be used, and a relatively higher negative voltage can be used for portion 64.

In one possibility, but not a final explanation, that a good transfer is achieved with a low positive voltage at section 66 and a high negative voltage at section 64, The transfer of charge from the transfer member 40 to the photoconductive surface will occur, which will result in at least partial neutralization of the charge on the drum.

Normally, portions 66 and 64 are separated by regions on the photoconductive surface of intermediate potential so as to prevent unwanted discharge between portions 64 and 66. The outer border of regions 64 and 66 is typically
As described above in connection with the above, it is determined to avoid electrical breakdown between the regions 64 and 66 and the photoconductive surface 16.

Referring now to FIG. 4, there is shown a cross section of an intermediate transfer member particularly useful in the apparatus shown in FIG. However, this is not an inevitable scale section. The intermediate transfer member, generally designated by the numeral 70, is typically comprised of a high strength substrate 72, typically 10 μm thick, such as Kapton ™, upon which an elastic layer 74 is disposed.
Is preferably provided.

A resistance heating layer 76, typically made of a nickel-chromium alloy, is formed on the elastic layer 74 and connected to a power source to heat the intermediate transfer member 70 as desired and Preferably, it assists in the transfer to On top of the heating layer 76 is typically 5 μm
An insulating layer 78 made of polyurethane is disposed.

Disposed over insulating layer 78 is a generally parallel array 80 of generally uniformly spaced, selectively energizable conductors 82. The elongate axis of the conductor 82 is substantially perpendicular to the direction of movement of the intermediate transfer member 70 when actuated, for example, as shown in FIG.

Conductor 82 is typically 35 μm thick
The width is 500 μm, and is separated by about 250 μm. These conductors are typically thermally conductive, such as a silicone-polyurethane copolymer containing as little as 2% Degussa Printex XE-2 ™ manufactured by Degussa Actchengezelshaft, Frankfurt, West Germany. Material with a thickness of about 100
Approximately 10 ⁵ ohm-c over conductor 82 at μm
embedded in a layer 86 having a resistance of m. Syl-Off having a thickness of typically 10 μm manufactured by Dow Corning from above this layer 86
A release layer 88 such as a trademark is disposed.

Referring to FIG. 5, this drawing shows that the resistance heating layer 76 is not continuous and is formed of a substantially parallel array 90 of selectively energizable conductors 92 that are substantially uniformly spaced. 5 shows an intermediate transfer member similar to that shown in FIG. 4 except for the following. The elongate axis of the conductor 92 is substantially perpendicular to the direction of movement of the intermediate transfer member 70 when actuated, for example, as shown in FIG.

The array 90 provided in place of the continuous elastic heating layer enables the heating of the intermediate transfer member 70 to be spatially selectable, for example, from the photoconductive surface 16 to the substrate 42.
Heating of the intermediate transfer member can be performed only along the path extending to (FIG. 2).

[0139] Heating of the image carried on intermediate transfer member 70 along its path is described in the assignee of the assignee filed November 21, 1988, the disclosure of which is incorporated herein by reference. US Patent Application Serial No. 27
No. 2,323, the photoconductive surface 16
Image heating without the risk of thermal damage to the substrate and the termination of image heating at the exact desired level to improve transfer of the image from the intermediate transfer member to the substrate. The improvement of image transfer in this way was 198.
The assignee's related U.S. patent application, entitled "Method and Apparatus for Imaging Using an Intermediate Transfer Member," filed January 4, 09, is described and claimed. The teachings are incorporated herein by reference.

This selective heating is most effective when the heat capacity of the intermediate transfer member is relatively small, and the heating and cooling are performed as described in the above-mentioned US Patent Application.

An intermediate transfer member having one or more conductive arrays that can be selectively heated has been described and shown as a belt in FIGS. 4 and 5, the structure of which is similar to that of the apparatus shown in FIG. It will be appreciated that the same applies to roller-shaped intermediate transfer members as used. In addition, some layers in the structures of FIGS. 4 and 5 may be used, for example, if heating is not desired.
It can be omitted if desired.

Referring to FIGS. 6-10, these figures show the use of a conductor that can be selectively biased to a roller configuration. FIGS. 6 and 7 show the intermediate transfer member roller 40 with at least one array 80 of selectively energizable electrical conductors in operative engagement with the substrate 42 and the drum 10. The shoe 100 includes one or more brushes or contacts that contact one or more groups of conductors.

FIG. 7 shows a preferred structure of the array 80 of rollers 40. The conductor 82 is circumferentially offset near the periphery of the roller 40. The purpose of this offset is to allow the biasing shoe 100 to be located outside the nip between the roller 40 and the drum 10,
Nevertheless, the desired voltage is applied to the conductor 82 located at the nip to improve transfer and minimize electrical breakdown as described above.

FIG. 8 shows a structure in which a shoe assembly of the type shown in FIG. 10 is mounted in tension in operative engagement with the roller 92. This roller 92
6. Roller 4 shown in FIG. 7 except that conductors 82 no longer need to be offset as shown in FIG.
Same as 0. The shoe assembly is held in tension contact with the roller 92, and the shoe 110 (FIG. 10)
Contacts 112, 114 and 116 are in contact with the ends of conductor 82. As shown in FIG. 10, the diameter of the drum 10 is reduced in a region facing the top of the conductor 82 so as to form a gap in the shoe 110.

Therefore, as shown in FIG.
12 is held at -2000 volts, contacts 114 are held at 0 volts, and contacts 116 are held at +500 volts. As seen in FIG. 7, electrically connector 120 can have a desired voltage with respect to connectors 122, 124 and 126, respectively. These connectors have contacts 112, 114 and 1 respectively.
16 is connected.

An intermediate transfer member of the type shown in FIG. 5 has two conductor arrays 80 and 90 and a shoe assembly 11 located at opposite ends of rollers 92 as shown in FIG.
It will be appreciated that power is received through zero.

Reference is now made to FIG. 11, which shows an electrophotographic imaging apparatus generally similar to that shown in FIG. This device has the following differences. That is, the use of an intermediate transfer member has been eliminated because of the direct transfer from photoconductive surface 16 to substrate 130, such as paper. This direct transfer is performed by providing guide rollers 132, 134 and 136 for guiding the continuous web substrate 130, and a drive roller 138 cooperating with the support web 140. A suitable charging device, such as corona discharge device 142, charges the substrate at the transfer location so that image transfer from photoconductive surface 16 to substrate 130 is performed by electrophoresis.

According to a preferred embodiment of the present invention, the apparatus of FIG. 1 or FIG. 11 is constructed and operated with a curing roller 30 (FIGS. 1, 11-13). As shown in FIGS. 12-13, roller 30 includes a generally parallel array 150 of generally equally spaced selectively energizable electrical conductors 152. The axis of the conductor 152 in the elongated direction is, for example, substantially perpendicular to the moving direction of the curing roller 30 in the operation as shown in FIG. In this, the movement of the curing roller is indicated by arrow 154.

Conductor 152 is typically 35 μm thick.
And the width is 500 μm, separated by about 250 μm. An overall area 155 is formed between the curing roller 30 and the photoconductive surface 16 bounded by a virtual line 156. The chance of electrical breakdown occurring in this region is small due to the presence of the dielectric toner carrier meniscus. In this area, the structure compresses the toner particles of the image. This hardens, or hardens, the image on the photoconductive surface, resulting in improved image transfer therefrom. It should be understood that the roller 30 of FIG. 12 also acts as a squeegee roller, substantially removing most of the liquid from the image, further compressing the image physically.

FIG. 13 shows a further development of the device of FIG. In this, the roller 30 acts as a roller for metering, background removal and curing. In this structure, two regions 160 and 162 are formed and opposing voltages are applied to the conductors 152 in those regions, which is substantially the same as described above and shown in FIG. 3B. Is the same.

This structure is particularly useful for providing a roller 30 for removing and curing the background. Such a roller serves both to remove the background from the image and to cure the image prior to transfer.

In such a structure, the colored powder is generally negatively charged, and the image area on the photoconductive surface is positively charged. The direction of rotation of the photoconductive surface 16 and the roller 30 separated from the surface is as shown in FIG. Region 160 is energized to a positive potential, typically +200 volts, to attract and remove colored powder from the background area of photoconductive surface 16. Region 162 is energized to a negative potential, typically between -200 volts and -2000 volts, to cure the image by pressing the colored powder toward the image area on the photoconductive surface. .

Normally, a region of the roller 30 at intermediate potential is located between the regions 160 and 162 so as to prevent unwanted discharges between the regions 160 and 162. The outer boundary of region 162 is defined to avoid electrical breakdown between region 162 and photoconductive surface 16.

The measurement of the surplus liquid from the photoconductive surface 16 is as follows.
This is accomplished by reversing the roller 30 in the direction indicated by arrow 164, as is well known in the art.

Referring now to FIG. 14, this drawing shows an electrophotographic image forming apparatus. This device is substantially the same as the device shown in FIG. 11, with the following differences. That is, the roller 30 is a non-rotating curing member 170.
This member has a charged area 172 located inward of its edge, thereby preventing electrical breakdown.

The region 172 is formed between the member 170 and the photoconductive surface 1.
6 is selected such that no discharge occurs at the operating voltage when the gap between the two is filled during operation with the dielectric toner particle carrier liquid. This operating voltage is such that the photoconductive surface 16 is charged to 1000 volts in the image area,
When charged to 50 volts in the background area, the area 17
Preferably, the member 170 within 2 is at -200 to -2000 volts. The cured member is hydrodynamically shaped such that when the roller is lightly pressed against the photoconductor, the rotation of the roller pulls the roller away from the photoconductor surface by about 15 μm. preferable. Instead of 50
It can be made to be held at a fixed distance from the photoconductor about μm.

Alternatively, the majority of member 170 is charged and the upstream side of member 170 is spaced from the photoconductor until the gap between member 170 and photoconductor is large enough to prevent dielectric breakdown and corona generation. The ends can be shaped to form a meniscus of an insulating carrier liquid.

It will be appreciated that the sign of the various voltages was provided, for example, using negatively charged toner particles. The present invention is equally applicable to the case of negatively charged photoconductors using positively charged toner particles, with appropriate changes being made with the sign of the voltage described.

Those skilled in the art will recognize that the present invention is not limited to what has been particularly shown and described above. Rather, the scope of the present invention is limited only by the following claims.

[Brief description of the drawings]

FIG. 1 is a simplified cross-sectional view illustrating an electrophotographic apparatus constructed and operated in accordance with a preferred embodiment of the present invention.

[Figure 2] A simplified cross-sectional view showing the structure is actuated by electronic photographic apparatus in accordance with another preferred embodiment of the present invention.

FIG. 3 is a simplified conceptual cross-sectional view illustrating an image transfer apparatus constructed and operated in accordance with a preferred embodiment of the present invention (FIG. 3).
3A) and a simplified conceptual cross-sectional view of an image transfer device constructed and operated according to another preferred embodiment of the present invention (FIG. 3B).

FIG. 4 is a simplified cross-sectional view illustrating an intermediate transfer member constructed and operated in accordance with a preferred embodiment of the present invention.

FIG. 5 is a simplified cross-sectional view showing a portion of an intermediate transfer member constructed and operated according to a preferred embodiment of the present invention.

FIG. 6 is a view showing a part of FIG. 3B and showing a supply source for a potential applied to an intermediate transfer member.

FIG. 7 is an explanatory view showing an arrangement of conductors in an intermediate transfer member used in the apparatus of FIG. 6;

FIG. 8 is a simplified side view showing a configuration of a power supply device associated with an intermediate transfer member.

FIG. 9 is a line IX- of FIG. 6 for one embodiment of the present invention.
The side view along IX.

FIG. 10 is a simplified drawing of a power supply useful for the configuration of FIG. 8;

FIG. 11 is a simplified cross-sectional view illustrating an electrophotographic apparatus constructed and operated in accordance with another preferred embodiment of the present invention.

FIG. 12 is a simplified conceptual cross-sectional view illustrating an apparatus for curing an image constructed and operated in accordance with a preferred embodiment of the present invention.

FIG. 13 is a simplified conceptual cross-sectional view illustrating an apparatus for curing an image constructed and operated in accordance with another preferred embodiment of the present invention.

[14] Further simplified cross-sectional view showing a is the electronic photographic device operation is constituted by another preferred embodiment of the present invention.

 ──────────────────────────────────────────────────の Continued on the front page (31) Priority claim number 306,079 (32) Priority date February 6, 2001 (1989.2.6) (33) Priority claim country United States (US) (72) Inventor Amiran Lavonne 59 100 Bat Yam, Balfour Street 143/5 (72) Inventor Hannah Pinjas 58 100 Holon, Sprinsak Street, 20 (72) Inventor Jacob Krumberg 76 100 Rehoboth, Israel , Miller Street 21/13 (72) Inventor Jossi Adam Israel 76 100 Rehoboth, Derek Jabne, 57 (72) Inventor Paul Fenster Israel 49 100 Petak, Ahad Harm Street, 59

Claims (15)

[Claims] An image bearing surface (16) arranged to support a liquid toner image including an image area having a toner powder charged to a given polarity and a background area, and curing the liquid toner image. A curing means (26) for removing liquid therefrom, said curing means comprising a squeegee roller, at least a portion of which is charged and pressed against the image bearing surface. The image is transferred to a substrate (42).
An intermediate transfer member (40) for receiving the toner image from the image bearing surface (16) after the image has been cured for transfer to Charged to a voltage higher than about 500 volts and the squeegee voltage is about 2
An image forming apparatus, which is charged to 000 volts or less. 2. The image forming apparatus according to claim 1, wherein said squeegee roller is charged to a voltage higher than about 1000 volts. 3. An apparatus according to claim 2, wherein said squeegee roller is charged to a voltage greater than about 1100 volts. 4. An apparatus according to claim 1, wherein said intermediate transfer member is provided in an image transfer area (6).
2) An image forming apparatus, comprising: means for receiving the image and charging the intermediate transfer member to a transfer voltage lower than 1000 volts at least in the image transfer area. 5. An image bearing surface (16) arranged to support a liquid toner image including an image area having toner powder charged to a given polarity and a background area, and curing the liquid toner image. A curing means (26) for removing liquid therefrom, said curing means comprising a squeegee roller, at least a portion of which is charged and pressed against the image bearing surface. The image is transferred to a substrate (42).
The image bearing surface (16) after curing of the image for transfer to
An intermediate transfer member (40) for receiving a toner image from
At least a portion of the squeegee roller is charged to a voltage higher than about 500 volts with the same polarity as the polarity of the charged toner powder, and the squeegee voltage is charged to about 2000 volts or less; An image forming apparatus, wherein the transfer member receives the image in an image transfer area (62) and includes means for charging the intermediate transfer member to a transfer voltage of less than 1000 volts at least in the image transfer area. 6. The device according to claim 4, wherein
An image forming apparatus, wherein the transfer voltage is lower than 750 volts. 7. The device according to claim 4, wherein
An image forming apparatus, wherein the transfer voltage is about 500 volts. 8. An apparatus according to claim 1, wherein said charged squeegee roller applies a potential difference of about 1200 volts to 3000 volts between it and an image area of said image bearing surface. An image forming apparatus operable to provide. 9. An image support surface (16) arranged to support a liquid toner image including an image area having toner powder charged to a given polarity and a background area, and curing the liquid toner image. Curing means (26) for removing liquid therefrom, said curing means including a squeegee roller, at least a portion of which is charged and pressed against the image bearing surface, The image is transferred to a substrate (42).
The image bearing surface (16) after curing of the image for transfer to
An intermediate transfer member (40) for receiving a toner image from
At least a portion of the squeegee roller is charged to a voltage greater than about 500 volts with the same polarity as the polarity of the charged toner powder, and the squeegee voltage is charged to about 2000 volts or less; The squeegee roller operates to provide a potential difference of between about 1200 volts and 3000 volts between the squeegee roller and the image area of the image bearing surface. 10. An apparatus according to claim 8, wherein said potential difference is at least 1500 volts. 11. An apparatus according to claim 8, wherein said potential difference is at least 2000 volts. 12. An apparatus according to claim 1, wherein said squeegee roller is supported at a potential opposite to the potential of the image area on the image bearing surface, and thus said squeegee roller is mounted on said image squeegee roller. An image forming apparatus for removing excess liquid from an image while hardening the image. 13. An image bearing surface (16) arranged to support a liquid toner image including an image area having a toner powder charged to a given polarity and a background area, and curing the liquid toner image. Curing means for removing liquid therefrom (26)
Wherein said curing means includes a squeegee roller that is at least partially charged and pressed against an image supporting surface.
After transfer of the image, the image supporting surface (1)
6) including an intermediate transfer member (40) for receiving the toner image from (6), wherein at least a portion of the squeegee roller is charged to a voltage greater than about 500 volts with the same polarity as the polarity of the charged toner powder; The squeegee voltage is charged to about 2000 volts or less, and the squeegee roller is supported at a potential opposite to the potential of the image area on the image support surface, thus allowing the squeegee roller to solidify the image and at the same time to remove excess liquid from the image. An image forming apparatus, wherein: 14. An apparatus according to claim 1, further comprising means for energizing said intermediate transfer member at least at a position where said image is transferred. 15. An apparatus according to claim 1, further comprising means for removing colored toner powder from said background area.