JPH08114999A - Equipment and method for conditioning of dry toner picture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording device for accurately generating color copy at a low cost by using dry developer. SOLUTION: This recording device for generating an image on a recording sheet 26 is provided with an intermediate member 20, a marking means for adhering the dry charged marking material 24 onto the intermediate member 20 so as to form a marking image thereon, a heater 32 coupled with the intermediate member and for heating the intermediate member 20 so as to form a viscous marking image 30 thereon, a conditioning roller for cooperating with the intermediate member so as to adjust the condition of the viscous marking image, and a means for transferring the viscous marking image 38 to the recording sheet 26 so as to permanently fix the viscous marking image 38, which is cooled at the time of coming into contact with the recording sheet, to the recording sheet.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to the development of dry toner images on a heated intermediate member. More particularly, it relates to a method and apparatus for conditioning a dry toner image and then delivering the image to a recording sheet.

[0002]

2. Description of the Related Art A typical electrostatic electrophotographic printing machine (photocopier, laser printer, facsimile, etc.) uses an image forming member exposed to an image to be printed. The exposure of the imaging member records an electrostatic latent image corresponding to the informational areas contained within the image to be printed on the imaging member. The latent image is developed by bringing the developing material into contact therewith. The developed image recorded on the photoconductive member is transferred, either directly or via an intermediate transfer member, to a support material such as paper. The developed image on the support material is subjected to heat and / or pressure to be permanently fused thereto. Two types of developing materials are used in electrostatographic printing machines. One type of developer material is known as a dry developer material, which comprises toner particles or carrier granules having toner particles triboelectrically fixed thereto. Another type of developing material is a liquid developing material that comprises a liquid carrier or dispersant having toner particles dispersed therein. Development using a liquid developer is performed in full-color image processing, for example, by systematic adsorption printing (text
It has many advantages such as urally attractive print). This is because in the development using the liquid developer, there is a swelling which has substantially no height. On the contrary, in the full-color image developed with the dry toner, the color areas often overlap. Prohibit high swells in the image. In addition, the liquid carrier, which in particular contains toner particles, may be cross-contaminated with the dye.
n) Full-color images with liquid developers are economically adsorbed if economically recovered. In addition, full color printing with liquid developers can provide a uniformly glossy or even matte finish, but powder toners can be used to reduce changes in toner deposit height. However, it is difficult to achieve a uniform finish due to the need for heat fusion and the like.

When a liquid developing substance is used, Isopar
Extra liquid carrier (such as a non-polar decane solvent) often sticks to the photoconductive member and is transferred to the transfer member (if present) or the support material. This liquid carrier later evaporates into the air. Typically, 0.5 grams of liquid carrier is absorbed by one copy paper and is run with each copy. The image is fused by heating the toner on its fusing point to allow it to flow into holes in the support material and / or into irregular surfaces, thus fusing the image. The heat required evaporates a significant proportion of the liquid carrier. It is desirable and known to remove liquid carriers from the support material to minimize image show-through and to prevent problems associated with their later appearance from the support material. Furthermore, by increasing the solid black area of the image before transferring it to the intermediate transfer member, the ability of the toner particles to form a high resolution image on the support member and thus on the support material is greatly improved. It Various techniques have been devised to remove excess liquid carrier from the imaging member. U.S. Pat. No. 4,286,039 (to Landa et al.) Is a deformable, squeegee roller or blotter roller biased by a voltage having the same sign as the charged toner particles of the liquid developer. Disclosed is an image forming apparatus including a polyurethane roller. The bias on the polyurethane roller causes it to streaking, smearing, tailing the developed electrostatic latent image,
Alternatively, the distortion is prevented and most of the liquid carrier of the liquid developer is removed from the surface of the photoconductive member. U.S. Pat. No. 4,299,902 (Some et al.) Discloses an image forming apparatus having an elastic roller that squeezes and absorbs excess liquid developer. The elastic roller is composed of a central roller, a porous elastic member wrapped around the roller, and an outermost elastic member having a plurality of through holes. U.S. Pat. No. 4,879,197
No. (Kohmura et al.) Discloses a pair of squeeze rollers for an electrophotographic machine comprising a metal roller having an elastic roller wrapped around the metal. The squeeze roller removes excess developer from the electrophotographic material. US Pat. No. 5,023,665 (Gu
ndlach) discloses an excess liquid carrier removal device for an electrophotographic machine. The device consists of an electrically biased electrode, which has a slit inside itself which is coupled to a vacuum pump. The vacuum pump removes the liquid carrier from the space between the electrode and the photoconductive member through a slit in the electrode. The electrical bias creates an electric field that prevents the toner particle image from being distorted as the vacuum draws air and liquid carriers out of the gap.

Development with dry developers has many advantages in monocolor imaging processes. For example, dry developers have the advantage of being less expensive than liquid developers and printing machines that use liquid developers, as are printing machines that use dry developers. There is a need for electrostatic printing machines that are capable of producing systematic adsorptive color printing with dry developers using substantially height-free bumps. In such devices, a simple construction, relatively inexpensive, and accurate approach to producing color prints is a goal in the design, manufacture, and use of electrophotographic printers. Came. This need has been especially recognized in the color and highlight color portions of electrophotography. The need to produce accurate and inexpensive color reproductions using dry developers has become more acute as the demand for high quality, relatively inexpensive color images and the machines that produce them has increased. According to the present invention, there is provided a recording apparatus including an intermediate member that generates an image on a recording sheet. The marking means deposits a dry charged marking material on the intermediate member to produce a marking image thereon. The heater communicates with the intermediate member to heat the intermediate member and form a viscous marking image thereon. The conditioning roller conditions the viscous marking image. Means are provided for transferring the viscous marking image to the recording sheet and for substantially permanently adhering the viscous marking image to the recording sheet which cools when in contact with the recording sheet.

According to another feature of the present invention, there is provided a recording apparatus having an intermediate member for producing a color image on a recording sheet. First marking means are provided for depositing a first color dry charged marking material on the intermediate member to produce a marking image thereon. The heater communicates with the intermediate member to heat the intermediate member and form a viscous marking image thereon. The conditioning roller conditions the viscous marking image. A second marking means is provided for depositing a second color dry charged marking material on the viscous marking image to form a composite viscous marking image on the intermediate member. Means are provided for transferring the composite viscous marking image to the recording sheet and for substantially permanently adhering the composite viscous marking image, which cools in contact with the recording sheet, to the recording sheet.

[0006]

DETAILED DESCRIPTION OF THE INVENTION While the present invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to the embodiments set forth herein. On the contrary, the invention is intended to cover all alternatives, modifications and equivalents which may be included within the spirit and scope of the invention as defined by the appended claims. Reference is now made to the drawings to understand the heated intermediate roller imaging process which forms the basis of the present invention. In these figures, like reference numbers are used to indicate like elements throughout them. FIG. 1 illustrates the various processing stages used to carry out the heated intermediate roll image processing of the present invention. Generally, the intermediate member 20 is the first component of the image forming apparatus. When rotated in the direction indicated by arrow 22,
The intermediate member will pass through three stages. That is,
A) an image adhering stage, B) an image liquefying or viscousizing stage, C) an image conditioning stage,
D) Image transfer / fusion (transfixing) stage,
Is. In the image processing, the intermediate member 20 is first advanced to the image attachment stage A. A number of alternative marking processes are available within deposition stage A for depositing marking material, or particles 24, on the surface of member 20. For example, it is also possible to use indirect or interactive marking techniques, in which the electrostatic latent image is first deposited on the surface of the member and subsequently floats in the carrier to contact the charged surface. Developed with such charged marking particles. Examples of indirect marking processes include the basic xerographic techniques commonly known for using photoconductive members that dissipate charge in response to a light image, and US Pat. No. 4,619,515 by Maczuszenko et al. No. 4,463,363 by Gundlach et al., And the pyroelectric method taught by Snelling in US Pat. No. 5,185,619. As a result, it is incorporated by reference for the teaching of the present invention. In addition, direct or non-interactive marking techniques can be used to deposit the marking particles 24 on the surface of the member 20. A non-interactive marking method is described in US Pat.
7 / 808,243), the result of which is that the teachings of which are incorporated by reference and further by Gundlach in US Pat.
Including selective transfer development as described in US Pat. No. 8,552, which results in the teaching of which is incorporated by reference, and is pyroelectric as described by Snelling in US Pat. No. 5,513,615. Direct marking is included, which is also hereby incorporated by reference.

Regardless of the marking technique used in the image deposition stage, these processes result in a developed image composed of regions of marking particles. This developed image is generated in response to the original image data understood to be an input to one of the plurality of marking processes described above. Subsequently, the marking particles 24 existing on the surface of the intermediate member are advanced through the image liquefaction stage B. Stage B such that it substantially surrounds the area between when the marking particles contact the surface of member 20 and when they are transferred to recording sheet 26.
In, the particles 30 are converted into a viscous or molten state by the heat internally applied to the member 20. Preferably, the viscous marking particle image is recorded sheet 2 using limited wicking.
6 and transferred and glued. More specifically, the member 20 has a heating element 32 which not only heats the inner wall of the intermediate member in the region of the fixed nip 34, but also because of the size and thermal conductivity of the intermediate member the marking particles. Keeps the outer wall of member 20 at a temperature sufficient to melt on the surface. As an alternative, the intermediate member 29 is a Dalal.
May be an “instant on” device as disclosed in US Pat. No. 5,087,946, et al., Or US Pat. No. 5,191,381 issued Mar. 2, 1993. It may also be a tubular heated roller made from a ceramic resistive material with a positive temperature coefficient of resistance, by Yuan, No., the result of which is incorporated by reference. The marking particles on the surface retain their position of attachment on the outer surface of the member 20 while softening and coalescing by the application of heat from the member 20, altering the image pattern that displays them. Try not to.

During the liquefaction or viscosification of the marking particles located on the outer surface of the member 20, the member continues to advance in the direction of arrow 22 until the viscous marking particles 30 reach the image conditioning stage C. . At image conditioning stage C, the viscous marking particles pass underneath a smooth electrically conductive roller that produces a less tacky, tackier image without degrading the image. A conductive roller 50 comprising a metal roller is preferred. Roller 50 has a polished finish and is biased by power supply 155, preferably to the same polarity as the viscous image of the intermediate member. One of the features of the present invention is that the voltage bias can be changed to capture some of the excessively thick image portions and change the voltage bias to improve the image quality. The cleaning blade 55 removes the toner adhered to the roller 50. The viscous marking particles are then moved to the image fixing stage. In the fixed nip 34, the viscous marking particles are subjected to a force by the normal force N applied through the backup roll 36 so as to come into contact with the surface of the recording sheet 26. A normal force N is one that produces a nip pressure, which is preferably about 100 pst, but which will cause an elastic blade or similar spring-like member uniformly biased across its width against the outer surface of the intermediate member. It may be added to the recording sheet via the recording sheet.

As the recording sheet passes through the fixed nip, it becomes viscous.
Marking particles moisten the recording sheet, and
Stronger against liquids due to greater adsorption between the hydrophilic particles
Between the surface of the member 20 having no strong affinity and the viscous particles
Compared with adsorption, viscous particles are recorded as image marks 38.
Completely transferred to the sheet. Furthermore, the image marks are recorded
Since they are transferred to the port 26 in a viscous state, those images are temporarily
Image marks go to the fixed nip and pass through them
When they can be cooled below their melting temperature, they are permanently
Will be fixed to. 2 shows that
Multi-color printing suitable for onographic printing processing
One of the machine configurations that can be used for the intermediate member 20 of the device.
is there. The intermediate member 20 is used as a light receiver. Middle part
The material is optional on the rigid member 5 with a base layer and an insulating upper layer
It is preferred to have a two-layer structure attachable to the.
The base layer has a thickness of 0.1 mm to 1.0 mm and is 130 °
10 at a temperature of C to 150 ° C⁶Ohm-cm-10¹¹Oh
It has a resistance of ohm-cm. Insulation top layer is 10 microns
Has a smaller thickness and a temperature of 130 ° C to 150 ° C
In 10¹²Ohm-cm-10 ¹⁴Has resistance of ohm-cm
I do. This top layer also has a debonding surface. Well
Also, both of these layers are of 50-80 durometer.
It preferably has matching hardness. Preferably
Is that both of these layers are on top of each other
Viton that can be formed by^TMConsists of
You.

The intermediate member 20 rotates in the direction indicated by the arrow. The intermediate member 20 receives the first latent image developed in the first color from the ionographic or ionic projection writing head 7. This latent image is then developed with the first developer in one of the plurality of development stations 9a, 9b, 9c, 9d. FIG. 2 shows a station 9a.
Shows the development performed in. Development stations 9a, 9b,
9c, 9d deposit marking particles on the surface of intermediate member 20 using non-interactive marking techniques. The marking particles are converted into a viscous or molten state by the heat internally added by the intermediate member 20. The intermediate member 20 includes a plurality of heating elements 32a, 32b, 32c.
And 32d. These heating elements not only heat the inner wall of the intermediate member in the region, but also keep the outer wall of the member 20 at a temperature sufficient to melt the marking particles present on the surface, preferably a heating controller. 21
Holds the intermediate member at a temperature of 130 ° C to 150 ° C. By holding at a temperature of 130 ° C. to 150 ° C., the second latent image can be developed without interference by the previously developed latent image, so that the color image is
It is produced with uniform, low noise transfer and with less paper curling. It is believed that the developed latent image is composed of loose marking particles that quickly adhere to the intermediate member. Because of the viscosity of the marking particles, the developed latent image flows into the intermediate member with greater contact and higher capacitance, resulting in a weaker charge on the marking particles. This reduces the contribution to blooming from previously developed images, and also
It reduces the tendency for loose toner to shift under high lateral electrostatic fields at the latent image boundary for the next color.

After each development station, a conductive roller 50 biased to the same polarity as the toner charge rotates over the viscous toner image. The rollers produce a less sticky, more tacky image without degrading the image prior to subsequent image processing by the ionic projection write head 7. The roller compresses the toner image to a lower stack height and further enhances the capacitance for subsequent charging of the image. The advantage of the present invention is that the conductive roller not only reduces the blooming of the charge on each image toner, but also reduces the tendency for previously developed toner to jump laterally at the boundaries of high voltage contrast. It is on both sides. Two
If more than one curler image is desired, the imaging means again passes through the ionic projection write head 7, at which point another latent image is formed on top of the first developed image,
This latent image moves so as to pass through the development station 9,
Here, for example, development is performed using the second marking particles of a color different from that of the first developer of the development station 9b. This process is repeated using the latent image after being developed by the development stations 9c and 9d until the final full-color image is formed. This full color image moves to the fixed nip 34.

At the fixed nip 34, the backup pressure roll 3 is applied to the liquefied marking particles of the full color image.
A normal force N applied through 6 applies a force to bring it into contact with the surface of the recording sheet 26. As the recording sheet passes through the fixed nip, the viscous marking particles moisten the surface of the recording sheet, and due to the larger adsorption force between the paper and the viscous particles, the member 20 which does not have a strong affinity for the liquid. The viscous particles are completely transferred to the recording sheet as compared to the adsorption between the surface and the viscous particles. Further, the full-color image transferred to the recording sheet 26 in a viscous state will be permanently fixed once the full-color image passes through the fixed nip and passes therethrough to be cooled. In summary, the present invention is a printing method and apparatus that uses a conditioning roller to condition a dry toner image. The intermediate member first functions as a receptor for the marking particles that display an image so that the marking particles can be deposited directly or indirectly on the member. The member is then exposed through an internal heat source to a temperature high enough to cause the marking particles to melt and coalesce. The viscous image is conditioned by the conditioning roller. Subsequently, the intermediate member is advanced further to deposit the second color marking particles on top of the previous image. The image is conditioned by the conditioning roller. The intermediate member is then advanced further and positioned so that the viscous marking particles present on its outer surface are in intimate contact with the surface of the recording sheet. Since the present invention utilizes the dimensional stability of the intermediate member to provide a uniform image deposition stage, the image transfer gap is better controlled and the image registration is better. Further, these benefits include reducing lateral jumps at the high voltage contrast boundaries of previously developed toner, as well as reducing blooming of the ionographic charge.

[Brief description of drawings]

FIG. 1 illustrates various processing stages used in the present invention.

FIG. 2 illustrates a multi-color heated intermediate roller image processing configuration suitable for ionographic printing processing.

[Explanation of symbols]

 20 Intermediate Member 26 Recording Sheet 30 Viscous Marking Particle 32 Heating Element 34 Fixed Nip 36 Backup Roll 38 Image Mark 50 Conductive Roller

Claims (2)

[Claims] 1. A recording apparatus for generating an image on a recording sheet, comprising: an intermediate member; marking means for depositing a dry charging marking substance on the intermediate member to generate a marking image thereon; A heater that communicates with the member and heats the intermediate member to form a viscous marking image on it, a conditioning roller that cooperates with the intermediate member to condition the viscous marking image, and a viscous marking image on the recording sheet. And a unit for substantially permanently adhering the viscous marking image, which is transferred and cooled when it comes into contact with the recording sheet, to the recording sheet. 2. A recording apparatus for producing a color image on a recording sheet, wherein an intermediate member and a dry-colored marking substance of a first color are deposited on the intermediate member to produce a marking image thereon. First marking means, a heater in communication with the intermediate member for heating the intermediate member to form a viscous marking image thereon, and a conditioning roller for cooperating with the intermediate member to condition the viscous marking image A second marking means for forming a composite viscous marking image on the intermediate member by depositing a second color dry charging marking substance on the viscous marking image; and transferring the composite viscous marking image to a recording sheet. A means for substantially permanently adhering the composite viscous marking image, which is cooled when it comes into contact with the recording sheet, to the recording sheet. A recording device comprising: