JPH05100579A - Color printing method and device using first and second transfer surface - Google Patents

Abstract

PURPOSE: To improve the quality of a color print by transferring a liquid toner image from the first master surface to the last image receiving surface by using a pressure sensitive or adhesive surface as an intermediate transfer surface. CONSTITUTION: The device is provided with a developing means for developing an electrostatically charged image by liquid toner, a 1st intermediate transfer surface 72 arranged adjacent to a photoreceptive surface 65 in order to receive the developed liquid image from the photoreceptive surface, and a drying means 81 for substantially drying the developed liquid image on the 1st intermediate transfer surface 72 in order to obtain the dry image. Besides, the device is provided with a 2nd intermediate transfer surface 23 which can come into contact with the 1st intermediate transfer surface 72. The 2nd transfer surface 23 is provided with adhesive or pressure sensitive characteristics effective in removing the dry image from the transfer surface 72. In this case the device is provided with a fusing means 50 for bringing the dry image into contact with the final image receiving surface 12 and which is effective in fusing the image on the surface 12.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD This invention relates generally to multicolor color printing systems and more particularly to forming a full color image with liquid toner on an intermediate surface and transferring it from this surface to a final image receiving surface. It relates to the device and method used.

[0002]

BACKGROUND OF THE INVENTION Full color copying is accomplished by using various multicolor electrophotographic printing devices. Electrophotographic printing as a method uses the common feature of using a photoconductive surface charged to a substantially uniform potential. The photoconductive surface is then imagewise exposed and an electrostatic latent image corresponding to each area of the original master to be reproduced is formed thereon. The electrostatic latent image charge is developed by contacting the toner material with the electrostatic latent image by a suitable developer material, such as toner in a carrier liquid or dry powder toner. It is developed by contacting the toner material with the electrostatic latent image by a suitable developer material, such as toner in a carrier liquid or dry powder toner. Toner particles are attracted to the charged latent image, and the resulting developed or toned image is then transferred from the photoconductive surface to the final copy sheet and permanently affixed thereto by fusing. ..

For black and white electrophotographic copying, the above method is performed only once. However, in the development of multicolor electrophotographic prints, the method is repeated for each color used, where it needs to be done for 3 to 4 or even more cycles. Also, the charged photoconductive surface is exposed to the filtered and decomposed image and the resulting electrostatic latent image is then developed with toner particles of a color corresponding to the subtractive primary color of the filtered image. To be done. By way of example, the electrostatic latent image is developed with cyan toner particles when a red filter is used,
The cyan tone image is then transferred to the copy sheet.

This type of process is used especially from dry powder systems and the steps are repeated with the following colors: For example, a green filter image is developed with magenta toner particles and a blue filter image is developed with yellow toner particles. Generally, each different tone toner powder image is sequentially transferred to the final image-receiving sheet in registration alignment with three or more powder images being transferred to the final image-receiving sheet. After everything is transcribed
The images are fused by heat or pressure, or both. The biggest drawback of these conventional devices is the time taken to do more processing for each color. It is obviously important that each of the overlaid powder images be accurately and properly aligned with each other during cycling and transfer to the copy sheet.

Another full color printing system utilizes an intermediate transfer surface or transfer member with a dry powder toner. Often these are rollers, but so are belts. In these types of systems as well, each image of dry powder toner is transferred from the photoconductive drum to an intermediate roller in registration alignment and then to the final image receiving surface. It is also possible to use multiple photoconductive drums.

The liquid toner method and its copiers have become popular. The liquid developer comprises a liquid carrier having toner particles dispersed therein, the liquid toner contacting the electrostatic latent image and imagewise depositing the toner particles thereon. Once the toner particles are imagewise deposited on the photoconductive surface, the image is transferred to the copy sheet either directly or via an intermediate transfer surface.

One drawback of using liquid toner developers is that the copy sheet becomes wet with both toner particles and liquid carrier. It is then necessary to remove the liquid carrier from the copy sheet. Various drying systems are devised to do this by evaporating the liquid carrier either before or after the fusing step. The use of an intermediate transfer surface such as a web, belt or roller facilitates removal of the liquid carrier. However, this intermediate transfer surface requires additional transfer which affects the quality of the transferred image. In general, liquid images are susceptible to bleeding and mixing with others, tending to distort or smear the resulting multicolor color copy. Liquid images are also known to reverse transfer from an intermediate or final surface to a photoconductive surface.

There are numerous representative patents dealing with intermediate transfer belts for both dry powder toners and liquid toner developers.

In Carlson, US Pat. No. 2,990,278, issued Jun. 27, 1961, dry powder toner is transferred and fused from a xerographic drum to an end copy sheet via an intermediate transfer belt. Apparatus and method are described.

US Pat. No. 3,893,761 to Buchan et al., Issued July 8, 1975, describes an apparatus having an intermediate transfer belt made from silicone rubber, the first substrate material. The toned image from is transferred by the use of pressure to a second support such as a final copy sheet by the use of heat and / or pressure. A radiant heater is used to heat the dry powder toner on the silicon belt prior to transfer.

US Pat. No. 3,923,392, issued to Buchan et al., Dec. 2, 1975, describes a device having an intermediate transfer belt made from a silicone elastomer, which has The dry powder image is pressure transferred to the transfer fusing station. Radiant heaters are used for intermediate transfer.

US Pat. No. 4,095,866 to Koeleman et al., Issued Jun. 20, 1978, describes photoreceptor belts, intermediate transfer belts, and final transfer and fusing devices. The first transfer station uses pressure on an intermediate transfer belt that is heated and made of silicone rubber. The image is transferred to the final image receiving surface by pressure and contact.

Koizumi, US Pat. No. 4,348,098, issued Sep. 7, 1982, describes a method and apparatus alleged to apply equally to dry powder or liquid toners, Here, the intermediate transfer drum is electrically biased by corona discharge in order to transfer the toner image onto it. The toner image is then transferred to the final image receiving sheet by a pressure roll and fused.

Suzuki's US Pat. No. 4,445,820, issued Jun. 12, 1984, describes an intermediate transfer belt made from silicone rubber or RTV rubber.
It receives the toner image from the photoconductive drum by light pressure. The toner image is then heated to the fusing temperature on the belt, and the final image receiving surface is crimped to the belt for transfer of the toner image.

US Pat. No. 4,542,978, issued to Tarumui et al., Issued Sep. 24, 1985, describes a high speed transfer device using a photoconductor and an intermediate belt, where the transfer is a belt and a photoelectric transfer. It is made by light contact between conductors. The intermediate belt surrounds a large diameter heating roller and the toner image is transferred to the final image receiving surface by the pressure between the heating roll and the second roll.

In Radulski et al., US Pat. No. 4,690,539, issued Sep. 1, 1987, a liquid toner image is transferred from a photoconductive member via an intermediate web to a final image-receiving sheet. Described device. The liquid carrier is removed from the intermediate web by vacuum, which will also ensure the toner particles to the intermediate web. A full-color image is transferred by corona transfer from this intermediate transfer surface to the final image receiving surface at the transfer station by spraying charged ions on the back side of the final image receiving surface.

In Langdon, US Pat. No. 4,708,460, issued Nov. 24, 1987, an intermediate position is placed in close proximity to, but not in contact with, the photoconductive member. It describes a device in which a liquid image is transferred to a member. This liquid image is simultaneously transferred from the intermediate transfer member to the final image-receiving sheet by contact transfer and is fused.

US Pat. No. 4,935,788 to Fantuzzo et al., Issued Jun. 19, 1990, describes a multicolor color printing system for liquid toner utilizing multiple development stations around a photoconductor. There is. Liquid images of different tones are transferred in registration registration to an intermediate member to form a multicolor liquid image therein, which multicolor liquid image is then transferred to the final image-receiving sheet and fused thereto. ..

In all of these known documents, the quality of the transferred image is not maintained as described above. These problems are due to the conductive intermediate transfer surface located adjacent to the photoconductor and the dried toner image from the conductive intermediate transfer surface, and the pressure and heat applied to the final image receiving surface. This is solved with the configuration of the present invention which utilizes a second intermediate adhesive transfer surface for transferring this.

One of the objects of the present invention is to provide a transfer device for a color print which uses three separate transfers to the final image receiving surface.

Another object of this invention is to transfer the liquid toner image from the photoconductor surface to the first intermediate transfer surface and then to the second intermediate transfer surface before contact transfer to the final image receiving surface. An object of the present invention is to provide a transfer device for color printing that is used for transfer.

One of the features of the present invention is that the first intermediate transfer surface has a conductive and non-oxidizing surface, and the dry toner adheres to the second intermediate surface which is adhesive. That is, the surface is smooth without surface defects that cannot be achieved.

Another feature of the invention is that the initial transfer of the liquid toner image from the photoconductive surface to the first intermediate transfer surface is through a liquid filled gap.

Yet another feature of the invention is that the liquid image transferred onto the first intermediate transfer surface is dried thereon prior to subsequent transfer onto the second intermediate transfer surface. is there.

Yet another feature of the present invention is that some additional color images other than the tone of the color image originally transferred to the first intermediate transfer surface are developed on the photoconductive surface and the liquid is removed. To be transferred to the first intermediate transfer surface through the filled gap and to each other and also for the first transfer image in registration alignment.

Yet another feature of the invention is that this dry, registered color image is contact transferred to a second intermediate transfer surface having a dielectric silicon or fluorosilicone surface.

Yet another feature of the invention is that this color image is transferred from the second intermediate transfer surface to the final image receiving surface by contact between the final image receiving surface and the fusing roller. , Using contact and / or heating to fuse the full color image to the final image receiving surface.

Yet another feature of the present invention is that the first electrically conductive transfer surface can be either drum-shaped or belt-shaped.

Yet another feature of the present invention is that the second intermediate transfer surface can be either a roller, a drum, a belt or a plate.

One advantage of the present invention is that when the electrically conductive first intermediate transfer surface is contacted with a liquid carrier of toner particles, which is provided in a permanent gap between this surface and the photoconductive surface. Does not swell.

Another advantage of the present invention is that the toner image after transfer from the photoconductor surface is carried out twice, from the first intermediate transfer surface to the second intermediate transfer surface and then to the final image receiving surface. That is, there is no apparent decrease in resolution during the transfer.

Another advantage of the present invention is that the highly polished, smooth surface of the first intermediate transfer surface is essential to the second transfer surface due to the adhesion or tackiness of the second intermediate transfer surface. Is to transfer a 100% toner image.

The liquid toner image is transferred from the photoconductive surface through the liquid-filled gap to the first intermediate transfer surface and then contact transferred to the second intermediate transfer surface having an adhesive or tacky surface coating, and These and other objects, features and advantages are obtained with the method and transfer apparatus of the present invention which provides a third contact transfer to the final image receiving surface. The multicolor color images are overlaid on the first intermediate transfer surface and dried thereon before contact transfer to the second intermediate transfer surface.

DESCRIPTION OF THE INVENTION Objects, features and advantages of the invention will be apparent from a consideration of the following detailed disclosure of the invention, especially with reference to the accompanying drawings.

FIG. 1 shows a preferred embodiment of a printing device 10 which uses three separate image transfers to the final image receiving surface. The final image receiving surface is the printed paper 18. An exposure system 64, which is a laser or other optical imagewise exposure unit, is shown in connection with the first photosensitive surface 65. This photosensitive surface 65 is a photoconductor. Photosensitive surface or drum 65 rotates about axis 66 and has a charging corona 68 for producing a latent image of charge on surface 65 and a discharge corona 69 for reimaging on the surface. Development station 8 for photosensitive surface 65
The drum wiper 70 and the reverse roller 71 are used to remove the excess liquid toner applied in 4.

A development station, generally indicated at 84, includes a plurality of color toner modules, each module including a toner development roller 86 and a wiper 87. The wiper 87 may apply a uniform layer of toner to the photosensitive surface 65, which may be drum-shaped or roller-shaped, and is not transferred from the toner developing roller 86 after transfer onto the photosensitive surface 65. It is for removing toner. Toner Development The development modules are generally shown as yellow toner module 85, magenta toner module 88, cyan toner module 89 and black toner module 90. Additional modules can be used to get the required number of colors. Each module has a toner tank for holding liquid toner therein, and the toner developing roller 86 is allowed to run before the photosensitive surface 65 is wetted by contact between the surface 65 and the toner layer on the roller 86. Pass through.

A bias voltage is applied to the toner developing roller 86 to hold the toner on the roller. This bias voltage is less than the charge of the latent image on the photosensitive surface. The developing station 84 is a chain 9
1 and the drive sprocket 92 so that the modules 85, 88, 89 and 90 are then generally moved horizontally to the operative position for developing the photosensitive surface 65 with the toner of the required tone. There is. The reversing yoke (not shown) is a pin (not shown) on the chain 91.
Is coupled to the color module to redirect the modules 85, 88, 89 and 90 and return to their initial starting position.

When the photosensitive surface 65 receives one color toner on it, this one color toner image is transferred through the liquid-filled gap between the photosensitive surface 65 and the first intermediate transfer surface 72. .. The details of this transcription are assigned to the applicant and are assigned to U.S. Pat. No. 4,87, Nov. 7, 1989.
Further details are given in No. 9,184.

Each separate color image is a photoconductive surface 6.
5 is imagewise exposed and developed, and then transferred in alignment alignment through a liquid filled gap to the electrically conductive first intermediate transfer surface 72. Once each color image developed has been transferred in registration on the electrically conductive first intermediate transfer surface, the image is like a axial blower 81 cooperating with a heating element available from Dayton. Dried by any suitable means. The dried image is then ready for transfer to the second intermediate transfer surface 23, which is an adhesive or tacky surface formed of silicon or fluorosilicone in the manner described below. It is configured.

Adjacent to the electrically conductive first intermediate transfer surface 72, a wick station 74 and a cleaning station 7 are provided.
There is 6. The wick station 74 has a conditioned wick shoe 75, such as that sold by Exxon under the trade name Isopar, which is wetted by a non-polar insulating liquid. This wick station 74 is controlled by a separate control as to how to wet it. A cleaning station 76 having a cleaning roller 78 and a wiper blade 79 is arranged on the first intermediate transfer surface after the image is transferred from the conductive first intermediate transfer surface 72 to the second intermediate transfer surface 23 of silicon or fluorosilicone. On the other hand, it is operated by a cam and a clutch (not shown). Thereby, the conductive first intermediate transfer surface 72
Is cleaned and ready for the next image to be transferred to it.

The developed images of four or more color toners are each subsequently color-registered and dried on the electrically conductive first intermediate transfer surface 72 to provide a single full-color image, followed by eccentricity. Transferring is performed on the second intermediate transfer surface 23 by operating the cam 48 and rotating the drive fork of the cam follower 49 to which the second intermediate transfer surface 23 is attached. This moves and contacts the second intermediate transfer surface toward the electrically conductive first intermediate transfer surface 72. The tacky or adhesive surface of silicon or fluorosilicone on the second intermediate transfer surface 23 causes the first conductive layer to rotate as the first and second conductive intermediate transfer layers rotate in opposite directions. Substantially all of the dried full color image is removed from the mid layer 72. The second intermediate transfer surface 23 is supported around the fulcrum of the shaft pin 49.

The toner image is transferred to the print paper 12 by contact transfer by pressure and heat by passing through a nip formed by the second intermediate transfer surface 23 and the heated fusing roller 50. The pressure exerted on the fusing roller 50 is always maintained at an appropriate pressure through this contact transfer by using an appropriate air cylinder (not shown).

The paper 12 is transported into the nip between the fusing roller 50 and the second intermediate transfer surface 23 by the paper feed roller 14, the guide roller 17, the shield and the paper guide 15. The paper is then transferred under the positioning of each full-color image on the second intermediate transfer surface 23. Each printed paper 18 is then transferred by the guide roller 57 to the printed paper storage tray 16.

Photosensitive surface 65, electrically conductive first intermediate transfer surface 7
The second and second intermediate transfer surfaces must all rotate at the same surface speed, even though they may have different diameters. Also, the circumference of the first intermediate transfer surface must be larger than the image registered on it.

The printing apparatus of FIG. 1 transfers all four images onto the electrically conductive first transfer surface 72 in registration alignment. During this operation, the contact between the second intermediate transfer surface 23 and the first intermediate transfer surface must be cut off. When the transfer is completed and the full color image is completed and dried on the electrically conductive first intermediate transfer surface 72, the second intermediate transfer surface 23 moves to contact it. However, each respective image must be formed in a non-continuous manner.

On the contrary, the printing apparatus shown in FIG. 2 is capable of continuously transferring a multicolor color image to the conductive transfer surface or belt 25. As will be described in detail later, in this specific example, the second intermediate transfer surface 23
Can be in constant contact with the electrically conductive first intermediate transfer surface 25 during operation.

FIG. 2 is another specific example of the color printing apparatus generally indicated by numeral 10, and is a front view showing a portion where the front surface of the housing is removed to show the transfer mechanism indicated by numeral 24. Is. Housing 2
Reference numeral 0 includes a functional portion of the printer 10, which includes a paper feeding mechanism indicated by numeral 11, and supplies the final image receiving paper of the paper 12 in the form of a sheet from the paper feeding table. Paper 1
2 is fed into the printer 10 by a paper feed roller 14, and the individual paper sheets 12 are fed by a paper shield and a guide 15.
Underneath and through the guide rollers 17 into the interior of the printer 10, where the fusing rollers 50 and the second
It is supplied into the nip formed by the intermediate transfer surface or the roller 23.

When the color image is transferred to the paper 12 in a manner described in more detail below, the full color toned paper 12 is ejected from the printer by the printed paper vacuum transfer conveyor 58. A transfer conveyor 58 transfers printed paper through guide rollers 57 to a vertically movable printed paper support tray 16 which is vertically driven by a suitable drive motor (not shown) to collect a stack of printed paper 18. Is moved along a flexible support rail (not shown).

FIG. 2 shows the transfer mechanism 24.
An important element of this transport mechanism is the electrically conductive first intermediate transfer surface, shown as belt 25. Belt 2
5 can be a metal or a metal on a dimensionally stable thermoplastic film. The electrically conductive first intermediate transfer belt 25 moves in a continuous path around the drive roller 52 and the guide roller 53. Roller 5
2 is driven by the same motor (not shown) that rotates the developing drum 35, on which drum is either a photopolymer master or a reimageable photoconductor, either permanent or reimageable. One of the masters is mounted. The belt 25 is kept in a constant tension by a controlled air cylinder 55 and a belt tension roller 54 that contacts the belt across its width.

The electrically conductive first intermediate transfer belt 25 is preferably a laminate made of an electrically conductive material (not shown), such as a thermoplastic film, polysulfone, polyethersulfone or polyvinyl chloride, polyetherimide. , An aluminum coating, suitably adhered to an underlying support dielectric layer (not shown). The belt surface should be smooth and non-sticky. The dielectric layer is thermally stable and is easily coated with an electrically conductive material such as aluminum or other metal foil, or any other material that can be metallized such as by evaporation, ion implantation or sputtering. May be It is also possible to use tin-plated stainless steel, on which gold-plated, for example brass, stainless steel or steel which is lightly oxidized and protected.

The aluminum coating or metallization layer has a thickness range of about 0.1 to about 1.5 mils (0.0025 to 0.038 mm), preferably about 0.5 to about 1 mils (0.013 to
The range can be 0.025 mm). When using a metallized layer, the thickness can be less than Angstroms (0.1 mm), but the controlling factor is the resistance value, which is less than 0.5 ohm / cm ² .

Metal belts of non-oxidizing materials such as stainless steel can be about 1 to about 30 mils (0.025 to 0.75 mm) thick, but preferably about 5 to about 15 mils (0. 0.13 to 0.38 mm). 1 to several mils or less, preferably 0.25 on metal or metallized substrate
A very thin polyvinylidene fluoride coating of ~ 1 mil or less can be used as the conductive polytetrafluoroethylene on the conductive substrate. It should be noted that the contact surface of this first intermediate transfer surface, regardless of the material used, must be extremely smooth for good toner release during transfer to the second intermediate transfer surface 23. ..

The electrically conductive metal layer (not shown) may be in the aforementioned thickness range and may be any suitable metal or electrically conductive material. A transfer voltage is applied through the conductive metal layer to achieve an electrostatic field to attract oppositely charged toner particles through the liquid-filled gap in the surface of the conductive metal material or coating.

The dielectric layer (not shown) is about 3 to 3 because the laminated electrically conductive first intermediate transfer surface or belt 25 is a dimensionally stable material under heat and tension.
It should also be thermally stable over a thickness range of about 15 mils (0.075 to 0.38 mm).

The transfer mechanism 24 includes a wick station 28 for applying a non-polar insulating solvent to the surface of the conductive first intermediate transfer belt 25. The solvent preferably comprises a mixture of branched chain aliphatic hydrocarbons, such as those available under the trade name Isopar from Exxon. The solvent is held in a tank 29 and has a wick roller 30 rotatably mounted therein for applying the solvent to the belt 25. The roller 30 is partially immersed in the solvent in the tank 29 and applies a uniform coating to the belt 25.

A plurality of color developing modules, generally designated by numeral 31, are arranged adjacent to the path of the electrically conductive first intermediate transfer belt 25. The slides 32 can be pulled out horizontally from the front of the printer 10 in order to move each module and to make it easy to put in and take out and maintain.
It is slidably mounted on top. Each module 31
Includes a color toner tank 34 of the color tone to be used. These are typically cyan, magenta, yellow and black in a four color image. The individual color toners in each module are pumped from their respective toner tanks 34 to developing electrodes 39, as seen in FIG.

As each developing drum 35 rotates about its respective shaft 61 mounted on a support plate (not shown), the removable master or photo image receiving material mounted on the circumference of the drum will be a liquid toner. It is developed by being wetted by. A corona charging unit 36, a discharge corona unit 41, a wiper plate 42, a cleaning roller 44, and the like are arranged counterclockwise on the circumference of the drum 35 behind the developing electrode 39 with respect to the developing drum 35 in each module 31. .. Above the toner tank 34 of the developing station is a suppression corona unit 45. There is a reverse roller 46 rotatably mounted in the toner tank 34, which cooperates with the suppression corona unit 45 to provide extra space around the developed color toner image on the master or photoconductive surface of each drum 35. Serves as a solvent remover. The color toner is dispersed in a non-polar insulating solvent composed of a mixture of branched aliphatic hydrocarbons such as the above-mentioned Isopar solvent.

When a detachable photo receiver such as a photoconductor is used as the master instead of the photopolymer, the exposure lamp 40 is used between the corona charging unit 36 and the developing electrode 39. An opaque toner mask would be used when using, for example, a photoreceptor of an organic photoconductor. In this case, the background or non-image areas are discharged by the exposure lamp 40.

November 7, 1989, assigned to the applicant
When a photopolymer master, such as those described in US Pat. No. 4,879,184, issued to Nissha, is used, the photopolymer creates a latent image prior to placement on drum 35 in printer 10. To expose. This photopolymer crosslinks only when exposed to light. The charge from the corona charging unit 36 remains on these crosslinked areas and the non-crosslinked non-image areas are attenuated due to their low resistance.

The coating of the electrically conductive intermediate transfer belt 25 and the master with a non-polar insulating solvent and liquid toner is applied to the transfer belt 25 through the gap filled with liquid.
On the other hand, it is important to electrostatically transfer the color toner developed image on each drum 35. This gap is maintained between each drum and the transfer belt 25 by a cam-operated gap spacing adjuster 26 and a transfer roller 27 attached thereto. The transfer roller 27 can also be used for adjusting the positioning of the color image between each developing drum 35 and the first conductive intermediate transfer surface 25 by adjusting the gap interval adjuster 26. The transfer is performed by applying an electric field to the electrically conductive first intermediate transfer surface or the metal conductive layer in the belt 25 by a continuously applied high voltage electric charge. This charge is approximately 0.001 to approximately 0.003 inches (0.025 to 0.07) between the master or photo receiver and belt 25.
The toner image on each master is transferred through the gap of 5 mm in combination with the use of the transfer roller 27. Transfer through this liquid-filled gap is described in US Pat. No. 4,877, issued Nov. 7, 1989, assigned to the applicant.
This is done as detailed in No. 9,184.

Intermediate transfer belt 2 in which each color image is electrically conductive
After the transfer to No. 5, the residual toner not removed from each photoconductor surface or master is cleaned by the cleaning roller 44.
And the wiper plate 42. The charge remaining on the master or photo receiver is enhanced by the discharge corona unit 41 before the master or photo receiver is recharged and developed to repeat the transfer in another print cycle. It is erased by the AC discharge of the voltage.

After all four or more color images have been transferred onto the electrically conductive first intermediate transfer belt 25, the carrier liquid is air knife or air dryer 4.
3 removes from the toner particles.

The four or more color toner developed images form a single full color image by superimposing the next color image on the electrically conductive intermediate transfer surface or belt 25, respectively. This single full-color image is then urged by the eccentric cam 48 to rotate the fork-shaped cam follower 49 to which the second intermediate transfer surface 23 is attached, and the conductive first intermediate transfer surface 25. It is transferred to the second intermediate transfer surface 23 by moving it toward. The adhesive or adhesive surface of the silicon or fluorosilicone is removed from the conductive first intermediate transfer surface 25 as the conductive first intermediate transfer surface 25 and the second intermediate transfer surface 23 rotate in opposite directions. Removes virtually all dried full-color images.

This toner image is then passed between the nip formed by the second intermediate transfer surface 23 and the fusing roller 50, whereby the print paper 1 is heated and pressed.
2 is transferred by contact transfer. The pressure on the fuser roller 50 is maintained by the use of a fuser roller air cylinder (not shown) to maintain a suitable pressure throughout this contact transfer. Fusing roller 50 is heated with pressure to aid in fusing the full color image to paper 12.

The paper 12 is fed by the paper feed roller 14, the guide roller 17, and the shield and the paper guide 15.
It is transferred into the nip between the second intermediate transfer surface and the fusing roller 50. Sheet 12 is fed under alignment with each full-color image on second intermediate transfer surface 23. Sheets of each printed paper 18 are conveyed by a paper conveyor 58 for stacking on the printed paper tray 16.

Some of the full-color toner image is on paper 1
2 is not completely fused to 2 and is an electrically conductive intermediate transfer belt 25.
If left on, it is removed at the belt cleaning station 50. The station 50 has a reverse roller 51 and a wiper blade 52, which are cammed up to engage the electrically conductive first intermediate transfer surface 25 when needed.

The tension roller 54 is attached to the arm 56 and is brought into contact with the belt 25 to be driven. The arm 56 swings around the fulcrum 60. The tension roller 54 is held by an air cylinder 55 in contact with the electrically conductive first intermediate transfer surface or the belt 25, and as shown by the solid and dotted lines in FIG.
Acts as an actuator to adjust the tension on the top. The belt 25 is thus maintained adjustable to a constant tension and can also be adjusted loose to allow replacement of the electrically conductive first intermediate transfer belt.

The diameter of each developing drum 35, including the thickness of the master or photoconductor surface, is such that the length of the conductive first intermediate transfer surface or belt 25 is the circle of four developing drums to which the master or photoconductor surface is attached. Designed to be equal to the lap. This positions the electrically conductive first intermediate transfer surface or seam in belt 25 directly relative to the non-image area on the master drum and relative to the fixture on drum 35. Become. Transfer surface or belt 2
Each time 5 passes through the fourth rotation of the drum 35, the seam on the drum 35 will line up with the seam on the belt 25 as this seam is indexed so that it lines up with the seam on the belt 25. This is done in order to achieve high speed color printing by using a conductive first intermediate transfer surface or belt 25.
, Each time it makes one revolution or traverse around its predetermined path, allows for the successive superposition of multiple full-color images, in this example four colors, on its surface or length.

In either of the specific examples shown in FIG. 1 or 2, the image formed by the toner particles is not heated to the melting temperature of the toner particles on the electrically conductive first intermediate transfer surface, and It is important to note that it is kept below that temperature. The color toner remains opaque on the electrically conductive first intermediate transfer surface. The temperature of the color toner is set on the second intermediate transfer surface by the fusing roller in order to facilitate transfer to the final image receiving surface or the sheet passing through the nip formed by the second intermediate transfer surface and the fusing roller. The temperature can be raised to the melting temperature or higher.

Although the present invention has been described above with reference to specific embodiments, many changes, modifications and changes in materials, arrangements of parts and processes, etc. may be made without departing from the spirit of the invention described herein. Obviously it can be done. For example, the master used on the first photosensitive surface in the present invention can use any suitable electrostatically imageable surface, including a photoreceptor. Photoconductor, a selenium photoconductors drum or carbazole and carbazole derivatives, and suitable organic photoconductors such as polyvinyl carbazole and anthracene are included, such as cadmium sulfide with a top layer of Mylar ^R polyester film or a polystyrene or polyethylene to ..
If a master with a permanent latent image is required, the master can be the surface of a zinc oxide or organic photoconductor developed with toner and fused onto the master, or an appropriately exposed liquid photoresist or dry film.

When a plurality of color toners are used to form a full-color image, it is possible to reproduce black from the three colors used to form and use a full-color image by using only toners of three colors not containing black. This is appropriate when black is not used for highlighting.

Further, the first intermediate transfer surface is electrically conductive.
I explained that there is, but Mylar ^R Polyester fi
A non-conductive material such as rum, or only one side
Aluminized mylar with minium^R Polyeste
It should be understood that a film such as a film is also good.
In this case mylar^R Printed polyester film
With a normal corona charging element installed in
Be charged. This surface is then non-polar as described above.
Moistened by insulating branched-chain aliphatic hydrocarbons, and
Developed with liquid toner on photosensitive or photoconductive surface
The image has a photosensitive or photoconductive surface and a first intermediate transfer surface.
Two liquid surfaces close to each other leaving a constant gap between them
Through a gap filled with liquid by
It is electrostatically transferred.

Accordingly, the purpose and scope of the claims appended hereto are variations that one skilled in the art may remember upon reading this disclosure.
It is intended to include all modifications and alterations.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an example of a multi-sheet color transfer device incorporating features of the present invention.

FIG. 2 is a schematic side view of another specific example of the multi-color printing apparatus of the present invention incorporating an electrically conductive intermediate transfer belt.

Claims (28)

[Claims] 1. A photosensitive surface (6) disposed adjacent to (a) imagewise exposure means (64) for exposing an image.
5); (b) charging means (68) cooperating with the photosensitive surface to charge the surface of the photosensitive surface; (c) developing means for developing the charged image with liquid toner; (D) a first intermediate transfer surface (72) disposed adjacent to the photosensitive surface (65) to receive the developed liquid image from the photosensitive surface; (e) for a dry image. A drying means (81) for substantially drying the developed liquid image on the first intermediate transfer surface (72); (f) a second contactable with the first intermediate transfer surface (72).
An intermediate transfer surface (23) of the second transfer surface (23) having an adhesive or tacky property effective to remove a dry image from the first transfer surface (72); ) Supplying means (1) effective for supplying the final image receiving surface (12) to the second intermediate transfer surface (23)
4); and (h) a fusing means (50) effective for bringing a dry image into contact with the final image receiving surface (12) and fusing the image thereto. A device for transferring a color image of liquid toner. 2. An apparatus for transferring a color image of liquid toner from a photosensitive surface to a final image receiving surface: a first intermediate adjacent to the photosensitive surface for receiving a developed liquid image from the photosensitive surface. From the transfer surface and the first intermediate transfer surface for transferring this dry developed image after drying on it,
Device characterized in that it transfers to a second intermediate transfer surface having an adhesive or tacky surface layer for removing all of the dry image and toner and a final image receiving surface and fuses the image thereto. .. 3. A device according to claim 1, wherein the photosensitive surface is photoconductive. 4. The apparatus according to claim 3, wherein the first intermediate transfer surface is smooth. 5. The apparatus of claim 4, wherein the first intermediate transfer surface is electrically conductive. 6. The apparatus of claim 5, wherein the electrically conductive first intermediate transfer surface is non-oxidizing. 7. The apparatus of claim 5, wherein the electrically conductive first intermediate transfer surface is metallic. 8. The apparatus of claim 7, wherein the electrically conductive first intermediate transfer surface is selected from the group consisting of aluminum, stainless steel or chrome plated steel. 9. An apparatus according to claim 1 or 2, wherein there is a gap between the photosensitive surface and the first intermediate transfer surface. 10. The apparatus of claim 9, wherein the gap between the photosensitive surface and the first intermediate transfer surface is filled by the liquid during transfer. 11. The device of claim 10, wherein the liquid further comprises a non-polar insulating solvent. 12. The apparatus according to claim 11, wherein the drying means is an air dryer. 13. The device of claim 10, wherein the second intermediate transfer surface is dielectric. 14. The device of claim 13, wherein the second intermediate transfer surface is silicone rubber or fluorosilicone. 15. The apparatus of claim 14 wherein the supply means further comprises a plurality of supply rollers while the final image receiving surface passes. 16. The apparatus of claim 15, wherein the fusing means further comprises a rotatable fusing roller. 17. The apparatus of claim 16, wherein the fusing roller is coated with silicone or polytetrafluoroethylene. 18. The apparatus of claim 16 wherein the fusing roller is heated to provide both heat and pressure during fusing. 19. To transfer a color image of liquid toner from a photosensitive surface to a final image receiving surface: (a) creating a charged latent image on the photosensitive surface; (b) this charging latent with the liquid toner. Developing the image; (c) applying a transfer voltage to the first intermediate transfer surface, and transferring the developed liquid toner image to the first intermediate transfer surface; (d) a substantially dry image. To dry the developed liquid image on the first intermediate transfer surface to: (e) substantially contact transfer the dry image to the second intermediate transfer surface having an adhesive or tacky surface layer; (F) supplying the final image receiving surface under pressure toward the second intermediate transfer surface to transfer the dry image from the second intermediate transfer surface to the final image receiving surface; and (g) ) Featuring each step of fusing the dry image transferred to the final image receiving surface How. 20. The method of claim 19, wherein steps (a)-(c) are repeated until the entire color image has been transferred to the first intermediate transfer surface. 21. The method according to claim 19, wherein a photoconductor is used as the photosensitive surface. 22. The method of claim 19 which uses an electrically conductive surface as the first intermediate surface. 23. The method of claim 22, wherein the dry image is maintained below the melting temperature of the toner on the electrically conductive first intermediate transfer surface. 24. A dry image is brought to a temperature above or above the melting temperature of the toner on the second intermediate transfer surface by a fusing roller to transfer the image and fuse it to the final image receiving surface. 24. The method of claim 23, wherein 25. The formation of a charged latent image comprises: (a) charging to generate a charge on the photosensitive surface;
20. The method of claim 19, which is performed by (b) exposing the photosensitive surface to produce charged latent image areas thereon. 26. Formation of a charged latent image comprises: (a) exposing a photosensitive surface to produce a charged latent image area thereon; and (b) generating a charge on the photosensitive surface. 20. The method according to claim 19, wherein the method is performed by a step of electrically charging. 27. The method of claim 26, wherein the dried image is maintained below the melting temperature of the toner on the first intermediate transfer surface. 28. The dried image is brought to a temperature at or above the melting temperature of the toner on the second intermediate transfer surface by a fusing roller to transfer the image and fuse it to the final image receiving surface. 27. The method of claim 26, which is