JP2003035994A - Electrophotographic toner improved in image quality and melt fixability and developing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing system which not only is improved in image quality but has excellent melt fixability and a developing method. SOLUTION: This developing system includes a nonmagnetic cylindrical shell for supplying a developer between feeding and developing zones. This shell may be rotatable and may be fixed as well. Further, a rotary magnetic core of preselected magnetic field intensity and means for moving toner particles from the shell to an electrostatic image by rotating at least this magnetic core are provided as a portion of this developing system. The developing system includes a fuser roll coated with silicone rubber or another elastomer or resin of low surface energy. The fuser roll is preferably in pressure contact with a back up or pressure roll.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION Cross-Reference to Related Applications This application is incorporated herein by reference in its entirety.
U.S. Provisional Patent Application No. 60 / 290,691 filed May 14, 001, 35 U.S.S. S. C§119
Claiming profit under (e).

TECHNICAL FIELD OF THE INVENTION The present invention relates to toner and developing systems for toner.

BACKGROUND OF THE INVENTION Digital printers and similar products produce documents that are often bookletted in post-print finishing equipment or folded for mail. Advances in toner and development systems are significant, but need to improve melt fixability of the toner image to prevent toner from bleeding or "scraping" in friction finishers that can cause gray or black stains on paper Still exists. In addition, the toner image may show noticeable cracks when the paper is folded if the proper properties are not present. Many of the toner fusing systems have excellent image quality, such as dark solid black, but tend to increase scuff. Therefore, there is a need for a method that avoids the aforementioned inconveniences by producing prints with high image quality and fusing.

DISCLOSURE OF THE INVENTION A feature of the present invention is to provide a developing system for providing a printed image having clear image quality and excellent melt fixing property.

Another feature of the present invention is to provide a toner using a developing system that provides prints with high image quality and high fuse fixability.

A further feature of the present invention is to provide a method for reducing the abrasion of printed images while maintaining the image quality.

Other features and advantages of the invention include:
Some will be set forth in the following description and some will be apparent from the description or will be appreciated by practice of the invention. The purpose and other advantages of the present invention are:
It will be understood and achieved by the elements and combinations thereof detailed in the following description and the appended claims.

To achieve these and other advantages in accordance with the objects of the present invention, as specifically and generally described herein, the present invention is directed to a toner development system. The development system comprises a supply of dry developer mixture containing toner particles and hard magnetic carrier particles. The development system further comprises a non-magnetic cylindrical shell for delivering developer between the supply and the development zone. The shell may be rotatable or fixed. In addition, a rotating magnetic core of preselected magnetic field strength and means for moving toner particles from the shell to an electrostatic image by rotating at least the magnetic core are also provided as part of the development system. It Additionally, the development system comprises a fusing roll coated with silicone rubber or other low surface energy elastomer or resin. This fusing roll is
It is preferably a silicone rubber filled fusing roller.

The toner used in the developing system includes at least one type of toner resin and at least one type of toner resin.
It is preferable that the toner contains one type of release agent, at least one type of surface treatment agent, and optionally at least one type of colorant and / or at least one type of charge control agent.

The invention further relates to a method for developing an electrostatic image with the toner described above. In the method,
The inside of a non-magnetic shell, which may be rotatable or fixed, that moves the electrostatic image member on which the electrostatic image pattern is placed within the developing zone and that has an alternating pole magnetic core with a preselected magnetic field strength that is outside. By controlling the direction and speed of the core and optionally the rotation of the shell so that the developer flows in the development zone in the same direction as the direction of movement of the image member. The electrostatic image member is developed by feeding developer into the development zone in relation to the charge pattern of the moving imaging member. In this case, it is preferable to use an electrograph two-component dry developer composition. Further, in the above method, after the toner is moved to the support, the image is melted and fixed on the support by passing the support on which the toner image is placed through a fusing roll. The fusing roll is a silicone rubber coated fusing roller or is coated with another low surface energy elastomer or resin. The fusing roll is preferably in pressure contact with a backup or pressure roll. The dry developer composition contains charged toner particles and carrier particles charged with a polarity opposite to that of the toner particles. The carrier particles are at least about 300 when magnetically saturated.
It exhibits a Gaussian coercivity and is at least about 20 EMU in an externally applied field of 1,000 Gauss.
A hard magnetic material that exhibits an induced magnetic moment of / gm is preferred. The carrier particles have a magnetic moment sufficient to prevent themselves from moving into the electrostatic image.

Further, the present invention comprises the above-mentioned toner particles,
A developer containing hard magnetic carrier particles.

The foregoing general description and the following detailed description merely illustrate and describe the present invention and are intended to further explain the present invention, as set forth in the claims. There is.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a development system and method for developing with a particular type of toner. Further, the present invention relates to the developer used in the developing system and the toner in the developer.

More particularly, the present invention relates, in part, to a development system. The development system comprises a supply of a dry developer mixture containing toner and hard magnetic carrier particles. A non-magnetic cylindrical shell, which may be a fixed shell or a rotating shell, is used to deliver the developer mixture from the supply to the development zone. The core, which comprises a plurality of magnetic pole portions arranged with alternating magnetic polarities around a magnetic core, is rotatable about an axis within the non-magnetic cylindrical shell. Further, there are means for rotating the core and optionally the shell to transfer the developer toner to the electrostatic image by carrying the developer mixture to the development zone.

Further, the development system of the present invention comprises a fuser roll coated with silicone rubber or other low surface energy elastomer or resin. This fuser roll is preferably in pressure contact with a backup or pressure roll. In this assembly, the fuser roll and the pressure roll are pressed together under sufficient pressure to form a nip. It is within this nip that melting or fusing occurs. The toner particles used in the development system include at least one toner resin, at least one release agent, at least one surface treatment agent, and optionally at least one colorant and at least one charge. It is preferable to contain a control agent, another conventional toner component or a combination thereof. The use of these toner particles in combination with the specific development systems described herein will result in an image that not only has excellent melt fixability, but also has improved image quality.

The construction of the development system includes a non-magnetic cylindrical shell, a magnetic core, the core and options, as detailed in, for example, US Pat. Nos. 4,473,029 and 4,546,060. Hei using a developing device having means for rotating the shell as
It is preferably a digital printer such as the Delberg Digimaster 9110 printer. The entire text of both of these patents is incorporated herein by reference. The development systems described in these patents can be adapted for use in the present invention. More specifically, the development systems described in these patents preferably use hard magnetic carrier particles. For example,
The hard magnetic carrier particles exhibit not only a coercivity of at least about 300 Gauss when magnetically saturated, but also an induced magnetic moment of at least about 20 EMU / gm in an externally applied field of 1,000 Gauss. You can The magnetic carrier particles may be binderless carriers or composite carriers. Useful hard magnetic materials include ferrite and gamma ferric oxide. The carrier particles are preferably composed of ferrite, which is a magnetic oxide compound containing iron as a main metal component. For example, iron (III) oxides formed from basic metal oxides such as those having the general formula MFeO ₂ or MFe ₂ O ₄ where M represents a monovalent or divalent metal and the oxidation state of iron is +3. , F
e ₂ O _3, and the like. The preferred ferrite is BaF
containing barium and / or strontium such as e ₁₂ O ₁₉ and SrFe ₁₂ O ₁₉ and formulas in which M is barium, strontium or lead as described in US Pat. No. 3,716,630. MO6Fe ₂
It is a magnetic ferrite containing O ₃ . The entire text of said patent is incorporated herein by reference. The possible sizes of magnetic carrier particles useful in the present invention vary, but preferably have an average particle size of less than 100 microns, more preferably from about 5 to about 45 microns.

There are several solutions to overcome these challenges. The most preferred solution of the present invention is to use surface-treated toner particles. Surface treatment with a surface treatment or spacing agent is associated with the charged image, at least in part, after the toner particles have been carried by the hard magnetic carrier particles to the development zone where the electrostatic image is present. The sufficient electrostatic force reduces the attractive force between the toner particles and the hard magnetic carrier particles to an extent sufficient to separate from the carrier particles. Thus, the preferred toner particles of the present invention, although attracted to magnetic carrier particles, can be separated from the hard magnetic carrier particles by electrostatic and / or mechanical forces and surface treatments on the toner particles. In other words, the spacing agent on the surface of the toner particles causes the toner particles, as described above, to the extent that the toner particles can be separated from the carrier particles by electrostatic or mechanical forces associated with the charged image. And is sufficient to reduce the attractive force between the hard magnetic carrier particles.

A preferred spacing agent is silica, such as R-972 from Degussa or H2000 from Wacker. Other suitable spacing agents include, but are not limited to, other inorganic oxide particles and the like. Specific examples include titania, alumina, zirconia and other metal oxides, as well as diameters such as acrylic polymers, silicone-based polymers, styrene polymers, fluoropolymers, their copolymers and mixtures thereof are preferred. Less than 1 μm (more preferably about 0.1 μm
m) polymer beads are also included, but are not limited to.

The amount of spacing agent on the toner particles is sufficient to separate the toner particles from the magnetic carrier particles by electrostatic or mechanical forces associated with the charged image. The amount of spacing agent is preferably about 0.05 to about 2.0% by weight, more preferably about 0.1 to about 1.0% by weight, based on the weight of toner. Most preferably 0.2 to about 0.6% by weight.

The spacing agent can be applied to the surface of the toner particles by a conventional surface treatment method such as a conventional mixing method such as rolling the toner particles in the presence of the spacing agent, but is not limited thereto. It is not done. The spacing agent is preferably dispersed on the surface of the toner particles. The spacing agent adheres to the surface of the toner particles and can be applied by electrostatic force and / or physical means. If you want to mix
Homogeneous mixing is preferred, and such mixing is accomplished by a mixer such as a high energy Henschel mixer that is sufficient to at least prevent agglomeration of the spacing agent or at least minimize agglomeration. Furthermore, if the spacing agent is dispersed on the surface of the toner particles by mixing with the magnetic toner particles, the aggregated spacing agent can be removed by sieving the resulting mixture. For the purposes of this invention, other means may be used to separate the agglomerated particles.

In the present invention, it is preferred that at least one release agent is present in the toner formulation. Examples of suitable release agents include one or more waxes. Useful release agents are known in the art. Useful release agents include low molecular weight polypropylene, natural waxes, low molecular weight synthetic polymer waxes, and commonly accepted release agents such as stearic acid and its salts.

The wax is preferably present in an amount of about 0.1 to about 10% by weight, based on the weight of the toner,
More preferably, it is present in an amount of about 0.5 to about 5% by weight. Examples of suitable waxes include, but are not limited to, polyolefin waxes such as low molecular weight polyethylene, polypropylene, their copolymers and mixtures thereof. More specifically, as a more specific example, a copolymer of ethylene and propylene, which has a molecular weight of preferably about 1,000 to about 5,000 g / mol, and particularly has a molecular weight of about 1,2.
A copolymer of ethylene and propylene, which is 00 g / mol, may be mentioned. As another example, the molecular weight is about 4,000.
Mention may be made of synthetic low molecular weight polypropylene waxes, preferably having a molecular weight of from about 3,000 to about 15,000 g / mol, such as polypropylene waxes of g / mol. Other suitable waxes are synthetic polyethylene waxes. A suitable wax is Polywax 2
000, Polywax 3000 and / or Uni
waxes available from Mitsui Petrochemicals, Baker Petrolite, such as Cid700, and Viscol
Waxes such as 550P and / or Viscol 660P available from Sanyo Chemical Industries. Another example of a suitable wax is Lic from Clariant.
Waxes such as owax PE130 may be mentioned.

The toner particles may contain one or more toner resins, the toner resins being at least one.
It may be optionally colored with one or more colorants by mixing the colorant of one type with any of the other ingredients. Although the coloring is optional, it is more common to include a coloring agent, and the coloring agent is included in the Color Index, Volumes I and II, 2nd edition (Colour), the contents of which are incorporated herein. Index, Volumes I a
nd II, Second Edition). The toner resin is, for example, U.S. Pat. No. 4,076,857, 3,938,992.
No. 3,941,898, 5,057,392,
5,089,547, 5,102,765, 5,1
12,715, 5,147,747, 5,780,
It can be selected from various materials including natural resins, synthetic resins and modified natural resins such as those described in Japanese Patent No. 195, etc. All of the above patents are incorporated herein by reference. Preferred resins or binders include polyesters and styrene-acrylic copolymers. The shape of the toner particles may be any shape, regular or amorphous, such as spherical particles obtained by spray drying a solution of the toner resin in a solvent. Alternatively, the spherical particles may be prepared as described in 9th 1979, the entire text of which is incorporated herein by reference.
It can be prepared by the polymer bead swelling method as described in European Patent No. 3,905, issued May 5, 2005.

Generally, the amount of toner resin present in the toner formulation is about 80, based on the weight of the toner formulation.
Is about 95% by weight.

In a typical manufacturing process, the desired polymeric binder for the toner is manufactured. Polymeric binders for electrostatographic toners are generally made by polymerizing selected monomers, combining the resulting polymers with various additives, and then crushing to the desired size range. To be done. During manufacture of the toner, the polymeric binder is subjected to melt processing. In this melt processing, the polymer is
Subjected to a high range of shear forces and temperatures above the glass transition temperature of the polymer. The temperature of the polymer melt is
It is partly due to the frictional forces of the melt processing. In the melt processing, the toner adduct is melted into the polymer mass.

The polymer is described in US Pat. No. 4,9 to Amering et al., Which is incorporated herein by reference in its entirety.
It can be produced using a limited agglutination reaction such as the suspension polymerization method disclosed in No. 12,009.

Useful binder polymers include vinyl polymers such as homopolymers and copolymers of styrene. As a styrene polymer, 40 to 10
0% by weight of styrene or styrene homologs, 0-4
Those containing 0% by weight of one or more lower alkyl acrylates or methacrylates. Other examples include fusible styrene-acrylic copolymers covalently loosely crosslinked with a divinyl compound such as divinylbenzene. Binders of this type are described, for example, in US Reissue Pat. No. 31,072, which is incorporated herein in its entirety. Preferred binders consist of styrene, alkyl acrylates and / or alkyl methacrylates, and the binder preferably has a styrene content of at least about 60% by weight.

Styrene-rich copolymers such as styrene butyl acrylate and styrene butadiene are also useful as binders, as are polymer blends. For such blends, the ratio of styrene butyl acrylate to styrene butadiene is 10: 1 to 1:10.
Can be. Ratios of 5: 1 to 1: 5 and 7: 3 are particularly useful. Styrene butyl acrylate and / or butyl methacrylate (30-80% styrene)
And styrene butadiene (30-80% styrene)
The polymers of are also useful binders.

Examples of the styrene polymer include styrene and α
Not only methylstyrene, para-chlorostyrene and vinyltoluene, but also acrylic acid, methyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl acrylic acid, Mention may be made of alkyl acrylates or methyl acrylates selected from ethyl methacrylate, butyl methacrylate and octyl methacrylate or monocarboxylic acids with double bonds, which are also useful binders. Also useful are condensation polymers such as polyesters and copolyesters of aromatic dicarboxylic acids with one or more aliphatic diols, such as polyesters of isophthalic acid or terephthalic acid with diols such as ethylene glycol, cyclohexanedimethanol and bisphenol. Is.

Useful binders can also be formed from copolymers of vinyl aromatic monomers with other monomers selected from either conjugated diene monomers such as alkyl acrylates and alkyl methacrylates or acrylate monomers.

The term "charge control" refers to the property of toner additives which modifies the triboelectric charging of the resulting toner. A wide variety of optional charge control agents for positively charged and negatively charged toners are available and can be used in the toners of the present invention. Suitable charge control agents are described, for example, in US Pat. No. 3,893,9.
35, 4,079,014, 4,323,634 and 4,394,430 and British Patent No. 1,50.
No. 1,065 and 1,420,839. The entire text of these patents is incorporated herein by reference.
Other useful charge control agents are described in US Pat. No. 4,624,90
7, 4,814,250, 4,840,864,
4,834,920, 4,683,188 and 4,780,553. The entire text of these patents is incorporated herein by reference. The charge control agents may be mixed and used. Specific examples of the charge control agent include chromium salicylate organic complex salts, and azo-
Iron complex salts, especially ferrate (1-), bis [4-[(5-chloro-2-hydroxyphenyl) azo] -3-hydroxy-N-phenyl-2-naphthalenecarboxamidate (2-)], Azo-iron complex salt consisting of ammonium, sodium and hydrogen (Organogai manufactured by Hodogaya Chemical Co., Ltd.
ron).

An optional additive to the toner is a colorant. In some cases, the magnetic component, if present, acts as a colorant obviating the need for a separate colorant. Suitable dyes and pigments are described, for example, in US Reissue Pat. No. 31,072 and US Pat. No. 4,160,644.
Nos. 4,416,965, 4,414,152 and 2,229,513. The entire text of these patents is incorporated herein by reference. One particularly useful colorant for toners used in black and white electrostatographic printers and printers is carbon black. Generally, the colorant is used in the range of about 1 to about 30% by weight, preferably in the range of about 2 to about 15% by weight, based on the total weight of the toner powder. Also, the toner formulation is a magnetic pigment,
It may also contain other additives of the type used in conventional toners such as colorants, leveling agents, surfactants, stabilizers and the like.

The remaining components of the toner particles as well as the hard magnetic carrier particles may be conventional components. For example, various resin materials such as fluorocarbon polymers such as poly (tetrafluoroethylene), poly (vinylidene fluoride) and polyvinylidene fluoride cotetrafluoroethylene may optionally be used as coatings on the hard magnetic carrier particles. it can. Examples of suitable resin materials for the carrier particles include silicone resins, fluoropolymers, polyacrylics, polymethacrylics, their copolymers and mixtures thereof, and other commercially available coated carriers and the like. However, it is not limited to these.

The present invention further relates to methods of forming images using the toners and developers of the present invention. Generally, in this method, an electrostatic latent image is formed on the surface of an electrophotographic element and the image is developed by contacting the latent image with a toner / developer of the present invention.

The present invention further relates to the use of the aforementioned development system in the development of electrostatic images with the toners of the present invention. In the method, the electrostatic image is contacted with the toner of the present invention. For example, in the above method, the electrostatic image member on which the electrostatic image pattern is placed is moved within the developing zone, and the alternating pole magnetic core having a preselected magnetic field strength may be located outside or may be fixed. A direction and speed of the core and optionally rotation of the shell so that it rotates inside a good non-magnetic shell and causes the developer to flow through the development zone in the same direction as the direction of movement of the image member. The electrostatic image member is developed by feeding the developer into the developing zone in a developing relationship with the charge pattern of the moving image forming member by controlling the electrostatic image member. In this case, it is preferable to use an electrograph two-component dry developer composition. The dry developer composition comprises charged toner particles,
The toner particles contain carrier particles having a polarity opposite to that of the toner particles. The carrier particles are hard magnetic materials that exhibit a coercivity of at least about 300 Gauss when magnetically saturated and an induced magnetic moment of at least about 20 EMU / gm in an externally applied field of 1,000 Gauss. It is preferable. The carrier particles have a magnetic moment sufficient to prevent themselves from moving into the electrostatic image. By using the toner of the present invention in the method described herein, various methods described in US Pat. Nos. 4,473,029 and 4,546,060 can be used in the present invention. The entire text of these patents is incorporated herein by reference.

The electrostatic image thus developed may be imaged in several ways, such as by imagewise photoattenuating the photoreceptor or by applying an imagewise charge pattern to the surface of the dielectric recording element. It can be formed by a method. When using a photoreceptor such as a high speed electrophotographic copier, it is particularly desirable to use halftone screening to correct the electrostatic image. The combination of development according to the invention with screening results in high quality images with high Dmax and excellent tonal range. As a typical screening method, there is a method in which an integral halftone screen as described in US Pat. No. 4,385,823 is used in combination with a photoreceptor. The entire text of said patent is incorporated herein by reference.

Further, the development system of the present invention comprises a fuser roll coated with another elastomer or resin having a low surface energy, such as silicone rubber or a tetrafluoroethylene resin. The silicone rubber that can be used as the surface of the fuser member may be room temperature vulcanized silicone rubber, low temperature vulcanized silicone rubber, or high temperature vulcanized silicone rubber. The fuser roll may have any shape such as a flat plate or belt type, but is preferably cylindrical. The fuser roll preferably has its core coated with a thin layer of silicone rubber.
The core may be made of various metals such as iron, aluminum, nickel and stainless steel or other elastic materials such as various synthetic resins. The core is preferably hollow, and a heating element is generally disposed therein to provide heat for the fusing and fixing operation. Suitable heating elements for this application are known to those skilled in the art and may be a quartz heating element consisting of a quartz envelope with a tungsten resistant heating element inside. The method of supplying the necessary heat to the fuser roll is not critical to the invention and the fuser member can be heated by internal means, external means, or a combination of both. Any heating means for providing sufficient heat to fuse the toner to the support is well known to those skilled in the art. The fuser roll is preferably in pressure contact with a backup or pressure roll. The pressure roll is preferably a metal core having a layer of heat resistant material.
In this assembly, both the fuser roll and the pressure roll are mounted on a shaft that is biased such that the fuser roll and the pressure roll are pressed together under sufficient pressure to form a nip. It is within this nip that melting or fusing occurs. The quality of the copy obtained by the fuser assembly is such that the nip is relatively hard and unyielding with a relatively soft layer.
layer) is better. In this method, the nip is formed by a slight deformation of the layer due to the bias of the fuser roll and the pressure roll. The relatively hard and non-yielding layer is polyfluoroethylene,
It may be composed of any known material such as propylene, silicone rubber or other similar material. In the present invention, fusing occurs when a thin support material, such as paper with a toner image thereon, passes between a fuser roll and a pressure roll. A fuser roll melts and fixes the toner image on the support material to form a printed image on the support. Using the above-described development system with the particular fuser assembly described herein with the particular toner formulation described herein, excellent image quality and good melt fixability with respect to printed images. Is realized. Excellent image quality may be achieved, for example, by the solid area reflection density or density described in the examples below.
and the good melt fixability can be confirmed mainly by the scuff value and crack width data provided in the following examples. Thus, the present invention provides a means for balancing properties, i.e., between image quality and fusing, in a system that provides high speed digital copying in a binary system. A fuser assembly that can be used in the present invention in combination with the specific toner formulations described herein as well as the developing system is described, for example, in US Pat. No. 5,534,3.
47, 5,629,061, 3,938,992
No. 4,046,990, 4,085,702, R
E31,072, 4,810,858, 4,39
5,109, 6,096,429, 6,067,4
38, 4,515,884 and 5,595,82
No. 3 is detailed. All of these patents are incorporated herein by reference in their entireties.

The various options described in these patents, such as the use of specific silicone rubbers or other optional ingredients such as the use of silicone or siloxane oils, can be incorporated into the present invention.

The developer in the developing system of the present invention is
It is preferable to be able to transfer toner to the charged image at a high rate. It is therefore particularly suitable for high volume electrophotographic printing and copying applications.

As described above, the print obtained by the developing method of the present invention has not only excellent melt-fixability but also improved image quality. A printed image fused and fixed on a support such as paper has improved abrasion resistance and reduced "toner scuffing" even when fed to a friction removal finishing device. Further, the image in which the toner is fused and fixed has a small crack width when the paper is folded, as shown in the following examples.

In another embodiment, instead of using a spacing agent on the surface of the toner particles, the electrostatic force on the charged image is sufficient to separate the toner particles from the carrier particles, for example from about 1,000 to about. The transfer potential may be significantly increased to a fairly high level up to 2,500 volts.

Another way to use the development system of the present invention is to increase the speed of a rotating magnetic core that can vibrate the toner particles to the extent that they can be separated from the carrier particles. The speed of the rotating core is at least about 100 rpm or at least about 500 rpm. In this embodiment, the speed of the rotating magnetic core is at least about 1,000 rpm, but at least about 2,000 rpm or at least about 2.5.
It may be 00 rpm, more preferably about 500 to about 2,500 rpm. These various embodiments can be used in various combinations.

Yet another method of using the developing system of the present invention is to apply an AC bias in superposition with the DC bias of the developing device. The AC bias promotes separation of the toner particles from the carrier particles by agitating the toner particles. The AC bias waveform is about 300
Preferably, it has a frequency of about ˜3,000 Hz and a peak-to-peak amplitude of about 0.2 to about 5 kV, about 1,000.
Most preferably, it has a frequency of about 1,500 Hz and a peak-to-peak amplitude of 2-3 kV. AC voltages with trapezoidal, most preferably square wave, waveforms are preferred over waveforms with lower average rms voltage, such as sine and triangle waves. The utility of AC bias as a means of increasing image density and reducing unwanted side effects in development with developing devices having rotating magnetic cores has been demonstrated in US Pat. Nos. 5,376,492, 5,394,230. Issue 5,
409,791, 5,489,975, 5,60
6,404 and 5,985,499. All of the above embodiments can be used in various combinations.

The invention can be further clarified by the following examples, which are merely illustrative of the invention.

Scraping Treatment A test device for measuring scuffing from an image-bearing support having a first surface and a second surface and having a toner image on said first surface. A first support having a first end and a second end and having one end extending beyond the first end of a flat surface (test sheet) A flat surface adapted to support the same, a restraining device for preventing movement of a second support (receiver sheet) along the length of the flat surface, and the first support in a test area. And a pressure pad adapted to apply a selected pressure to the second support, and adapted to pull the first support a selected distance within the test area with respect to the second support A puller, a calibrated scanner, and the conversion of scan results into numerical test results. And a computer program for The test sheet is
The first surface is arranged to face the receiver support. Any device that is effective to move the image-bearing surface of the test sheet in the test area relative to the receiver sheet by an effective distance while contacting the receiver sheet at a selected pressure is suitable.

The support provided for the test is usually paper. The test sheet is a paper having a toner image on its first surface. The paper is arranged such that one end thereof projects from the first end of the flat surface for contact with and release from the flat surface. Then, placing the second paper on top of the first paper and securing it in place will limit its movement relative to the flat surface. Next, pressure is applied to the test area, which is typically near the first end of the flat surface. Then, the first paper is peeled off from the flat surface. The abrasion of the toner obtained in the test area indicates the abrasion of the test sheet.

Such an apparatus and test method are described by Joh.
n R. Lawson, Gerard Darby I
I and Joseph A .; 20 by Basile
The agent reference number filed on March 13, 2001 is HE
It is disclosed in U.S. Patent Application No. (Undesignated) entitled "Scraping Test Method and Test Apparatus", ID-25,491. The entire text of this application is incorporated herein by reference.

The test apparatus is designed to detect the tendency of the test sheet to rub off by moving the test sheet within the test area under test pressure a selected distance with respect to the receiver sheet. It is understood that the device can operate with the test sheet above the receiver sheet as long as the test sheet is moved with respect to the receiver sheet.

The abrasion measurement is carried out in two steps. In the first step, the image on the test sheet is rubbed with a suitable device. In the second step, a quantitative measure of the scuffability of the test sheet is obtained by collecting and analyzing the results of the wear test.

The first step of creating a test sheet is accomplished by creating a test sheet in the system under evaluation. The test print for the scuff test is
It is desirable that the text is printed on the entire image forming area of 8.5 × 11 inch paper. A representative test sheet (target) is created. The text is preferably written on the test sheet at a suitable angle to the horizontal (ie 7 degrees). This is to eliminate streaks in the final image where there are breaks between words. In general use, this object will be postscript filed and sent to the printer. The printer then uses this input file to generate a test sheet for evaluation under specific test conditions. In general, standard paper such as Hammermill Bond is used for consistency between tests.

Once a test sheet has been created with the printer to be investigated, a sample for evaluation is created. These are produced by controlled rubbing of a test sheet (hammer mill bond) or any other standard paper against a receiver sheet. This control is
It is realized by using the above-mentioned device.

The device is used according to the following steps. 1. Place the test sheet upwards on a flat surface. The tip of this test sheet is the first of the flat surface
Align the sheet with the alignment mark so that it projects from the edge of the sheet. 2. A receiver sheet (second sheet) is placed on the test sheet. Align the receiver sheet with the first end of the flat surface. The other end of the receiver sheet is fixed in place. 3. Next, a known weight is put in a holder and placed on the stacked sheets. This weight exerts a known pressure on the stack of sheets in the test area. In these experiments, 3PSI was used. 4. The flat surface is then moved laterally until the leading edge of the test sheet engages the nip of the roller.
Rollers rotate to grab the test sheet and pull it from under the receiver sheet at a speed of 21 inches / second. Due to the relative movement between the test sheet and the receiver sheet, the toner of the test print is rubbed by the receiver sheet in the test area. This causes "toner smear" in the image on the receiver sheet. It has been shown that the degree of "smearing" in the test area correlates with a subjective measure of scuffing. 5. Repeat steps 1-4 4 times. These repeat tests can be processed in one of two ways. In the first method, all 6 replicates were tested for about 0.
Performed using a selective pressure of 5 to about 5 lb / inch ² (PSI). In the second method, three different pressures, eg 1
Two types of samples are made for each of PSI, 2PSI and 3PSI. The difference in the analysis of these two methods is explained in the next paragraph.

The test sheet is analyzed according to the following procedure. 1. Scan each test area with a calibrated scanner. The scanner is calibrated as follows. a) Scan a step tablet of known density under the same scanning conditions used to scan the print. b) Adjust the scanner contrast and zero so that the digital value of the step tablet is within the limits and given. c) Periodically check the value of the step tablet during repeated scans (eg, once an hour). 2. A calibrated scanner is used to scan 6 images from each test area. Select the scan option so that the six scanned test areas are assigned consecutive names. Scanning is performed in 230 × 230 pixels, 600 dpi, grayscale mode. The scanned test area is stored in the file server. 3. The data in the scan file represents the brightness of the pixels in the scanned area. 0 represents black and 255
Represents white. Calculate the standard deviation of the brightness values for each test area. The standard deviation has been shown to give the measure a good signal-to-noise ratio that correlates with the subjective assessment of scuffing. 4. If all six test areas were made with the same weight, the standard deviation values for luminance are averaged and the average value is reported as the scuff of the sample under test. 5. If the six test areas were made with three weights, the six standard deviation values would be regressed against the pressure at which they were tested. A least squares regression curve, preferably a quadratic linear regression, is suitable through this data to calculate an estimate of scuff at a given pressure. These scuff values as a function of pressure are the results reported for the test. 6. Confidence limits for the reported values are calculated for both data analysis methods. Generally, these confidence limits are ± 10% of the scuff value.

Various devices can be used to maintain a pressure pad with a weight that produces the desired pressure in place within the test area. Basically, the pressure pad is
It must be maintained in a position that allows the desired pressure to be exerted on the second sheet while it remains in place with respect to the flat surface when either sheet is moved. This can be achieved by various mechanical configurations. Such variations will be apparent to those of ordinary skill in the art.

[0055] were prepared Example Example 1 toner formulation of the following components.

[0056]

[Table 1]

A homogenous blend was obtained by dry powder blending these ingredients in a 40 liter Henschel mixer at 1,000 RPM for 60 seconds.

The resulting powder blend is then melt mixed in a twin screw co-rotating extruder to melt the polymer binder and disperse the pigment, charge agent and wax. Melt mixing, extruder inlet temperature: 230 °
F, temperature of the mixing area of the extruder: 230 ° F → 385 °
F, extruder die exit temperature: 385 ° F.
The processing conditions are powder blend supply rate: 10 kg / h
r and extruder screw speed: 490 RPM. The cooled extrudate was then chopped into granules about 1/8 inch in size.

After melt mixing, the resulting granules were finely pulverized with an air jet pulverizer and the volume-loaded median diameter was 1
Made into 1 micron particles. The toner particle size distribution is based on the Coulter Counter Multisizer.
inter multisizer). Then, the finely pulverized toner was classified by a centrifugal air classifier to remove very small toner particles and toner fine particles which are not present in the finally obtained toner and are not preferable. After classification and removal of particulates, the resulting toner has a particle size with a width expressed as diameter at 50% percentile / diameter in cumulative particle number at 16% percentile vs. particle size of 1.30 to 1.35. Had a distribution.

Next, the classified toner was surface-treated with fumed silica. Product name of Nippon Aerosil Co., Ltd. is R9
A hydrophobic silica of 72 was used. 2,000 grams of toner was mixed with 4 grams of silica to give a product containing 0.2 wt% silica. The toner and silica were mixed in a 10 liter Henschel mixer with a 4-element impeller at 2,000 RPM for 2 minutes.

The silica surface treated toner was sieved through a 230 mesh vibrating screen to remove any undispersed silica agglomerates and any toner flakes that may have formed during the surface treatment.

Example 2 Example 1 was repeated except that the toner formulation was formed using different ingredients. In particular, 100 parts of polyester resin (crosslinked bisphenol A polyester obtained from Nexpress) is used with 8 parts of carbon black (Regal 330 obtained from Cabot) and 2 parts of salicylate charge control agent (from Orient Chemical). Obtained E
84) and 2 parts Polywax 2000, a polyethylene wax obtained from Baker Petrolite.
A polyester-based toner was prepared by mixing 2 parts with Viscol 550P, a polypropylene wax obtained from Sanyo.
Then, 0.3 part of the toner is fumed silica coated with silane (R97 obtained from Degussa).
2) was used for surface treatment. The processing conditions are the same as in Example 1.

[0063]

[Table 2]

Both Examples 1 and 2 had overall better image quality than the Comparative Example. Examples 1 and 2
It had a higher reflection density for the maximum solid area density test object, a lower gloss level, and print characteristics of no voids in the image.

[0065]

[Table 3]

Other embodiments of the invention will be apparent to those of skill in the art upon reviewing the specification and practice of the invention disclosed herein. It is intended that the specification and examples be regarded as exemplary only, with the true scope and spirit of the invention being indicated by the appended claims and equivalents thereof.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 9/087 G03G 15/08 501A 9/097 501D 9/107 15/20 102 15/08 501 103 103 107 507 9/10 321 15/20 102 9/08 325 103 103 331 107 344 15/08 507L (71) Applicant 390009232 Kurfuersten-Anlage 52-60, Heidelberg, Federal real of germany (71) Applicant Press 500190395 Solutions L.U.S.A., 14653-1700, New York Rochester St. Paul Street, 1447 (72) Inventor Robert Dee Fields USA New York State 14622 Rochester, The Highlands 20 (72) Inventor Thomas J. Foster United States New York State 14454 Genesco, North Road 3247 (72) Inventor Paul El Nielsen United States New York State 14485 Lima, Doran Road 1843 ( 72) Inventor Thomas A. Judwin 14612 Rochester, North Park Drive, New York, USA 205 (72) Inventor Dinesh Chagi 14450 White Alder Circle, Fairport, New York, USA 14F Term (reference) 2H005 AA01 AA06 AA08 BA02 CA02 CA03 CA04 CA08 CA11 CA12 CA14 CA30 CB04 CB07 CB13 DA01 EA02 EA07 FA02 FB02 2H031 AC09 AC10 AC22 AC24 AD01 BA08 BA09 2H033 AA02 AA16 BA25 BA58 BB30 BB30 BB30 BB18 BB29 BB18 BB30 BB18 BB29 BB18 BB29 BB18 BB29 BB18 BB29

Claims (26)

[Claims] 1. A rotatable or fixed non-magnetic cylindrical shell for feeding a dry developer mixture of toner particles and hard magnetic carrier particles and for feeding the developer from the feed to a development zone. A rotating magnetic core of preselected magnetic field strength, means for moving at least the toner particles from the shell to the electrostatic image by rotating at least the magnetic core, and the core coated with an elastomer or resin. A toner development system comprising a fuser roll, wherein the toner particles are
At least one toner resin, at least one release agent, at least one surface treatment agent, and optionally at least one charge control agent or colorant, or both. The developing system for toner. 2. The developing system according to claim 1, wherein the core of the fuser roll contains a metal or a resin. 3. The developing system according to claim 1, wherein the core is hollow, and a heating body is provided inside the core. 4. The developing system according to claim 1, wherein the fuser roll is in pressure contact with a backup or pressure roll. 5. The fuser roll and the backup or pressure roll are mounted on a shaft that is biased such that they are pressed together under sufficient pressure to form a nip. Development system. 6. The developing system according to claim 1, wherein the surface treatment agent contains silica. 7. The developing system according to claim 1, wherein the surface treatment agent contains at least one kind of metal oxide. 8. The developing system according to claim 1, wherein the surface treatment agent contains at least one inorganic oxide. 9. The developing system according to claim 1, wherein the surface treatment agent contains at least one kind of polymer material. 10. The surface treatment agent is an acrylic polymer,
The developing system according to claim 1, which comprises a silicone-based polymer, a styrene polymer, a fluoropolymer, or a mixture thereof. 11. A rotating or fixed non-magnetic shell having an electrostatic image member carrying an electrostatic image pattern moved within a development zone and having an alternating pole magnetic core of a preselected magnetic field strength outside. And controlling the direction and speed of the core and optionally the rotation of the shell so that the developer flows through the development zone in the same direction as the image member travels. Develops the electrostatic image member by feeding developer into the development zone in a developing relationship with the charge pattern of the moving imaging member; transferring the electrostatic image pattern onto a support; Then, an electrostatic image is formed by melting and fixing the electrostatic image on the support by passing the support through a fuser roll whose core is coated with an elastomer or resin. A method for particle development, wherein the developer comprises charged toner particles and hard magnetic carrier particles charged to the opposite polarity of the toner particles, and the toner particles are at least One type of toner resin, at least one type of release agent, at least one type of surface treatment agent, and optionally at least one type of charge control agent and / or colorant, or both. The method. 12. The method of claim 11, wherein the method includes a flow of developer, and the moving imaging member and the flow of developer move at substantially the same velocity. 13. The carrier particles exhibit a coercivity of at least about 300 Gauss when magnetically saturated and an induced magnetic moment of at least about 20 EMU / gm in an externally applied field of 1,000 Gauss. The method of claim 11 comprising the hard magnetic material shown. 14. The method of claim 11, wherein the toner particles have a spacing agent on their surface. 15. The method of claim 14, wherein the spacing agent comprises silica. 16. The method of claim 14, wherein the spacing agent comprises at least one metal oxide. 17. The method of claim 14, wherein the spacing agent comprises at least one inorganic oxide. 18. The method of claim 14, wherein the spacing agent comprises at least one polymeric material. 19. The method according to claim 14, wherein the spacing agent comprises an acrylic polymer, a silicone-based polymer, a styrene polymer, a fluoropolymer or a mixture thereof. 20. The method of claim 14, wherein the spacing agent is present in an amount of about 0.05 to about 1.5% by weight based on the weight of the toner. 21. The method of claim 11, wherein the core of the fuser roll comprises a metal or resin. 22. The method of claim 11, wherein the core is hollow and has a heating body therein. 23. The method of claim 11, wherein the fuser roll is in pressure contact with a backup or pressure roll. 24. The fuser roll and the backup or pressure roll are mounted on a shaft that is biased such that they are pressed together under sufficient pressure to form a nip. the method of. 25. The at least one release agent comprises at least one wax, and the at least one toner resin comprises at least one polyester or at least one styrene acrylic toner resin. The developing system according to claim 1, wherein the developing system comprises: 26. The at least one resin is present in an amount of about 80 to about 95% and the release agent is present in an amount of about 0.5 to about 5.0%, based on the weight of the toner particles. The developing system of claim 1, wherein the surface treatment agent is present and is present on the toner particles in an amount of about 0.05 to about 2.0%.