Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/087—Binders for toner particles
  • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
  • G03G9/08797—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775 characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/087—Binders for toner particles
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/087—Binders for toner particles
  • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
  • G03G9/08791—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775 characterised by the presence of specified groups or side chains

Definitions

• This invention relates to a developer composition for a dry system for developing electrostatic latent images in electrophotography, electrostatic recording, etc., and more particularly to a developer composition having a pressure-fixing property.
• electrostatic latent images are well known. For example, in an electrophotographic process after the usual charging of the photoconductive layer, it is exposed to a light image based on an original to reduce or eleminate electrostatic charge in the exposed areas, whereby an electrostatic latent image is formed. The latent image is then developed by a developer called a "toner". As is well-known, the development process can use either a liquid or a dry developer. The latter process may be further classified into a two-component development process, using two kinds of particles, carrier and toner, and a one-component development process, using a toner only.
• the developed image is transferred onto a material such as paper. Thereafter, the toner is fixed on the paper by fusing the toner with heat or by softening a binding resin of the toner with a solvent, or by deforming the toner with only pressure.
• a pressure-fixing process has various merits with respect to energy saving, pollution and fire prevention as well as not requiring preheating for the fixing means.
• Other advantages are also obtained as compared with other fixing processes. However, these advantages have to be offset against other considerations, such as the strength of the fixed toner image, the producibility of the toner, antiblocking property, impact resistance, i.e. as one property is improved others are made worse. Therefore, it is very difficult to improve all these properties simultaneously.
• Japanese Patent Publication No. 9880/69 proposes a toner containing an aliphatic component having 6-25 carbon atoms
• Japanese published Patent Application 119231/77 proposes a toner containing a crystalline wax and an ethylene-vinyl acetate copolymer.
• Known wax-like materials may be excellent with respect to deformability by pressure.
• the strength of the fixed image is weak and hence the image readily comes off or smears when it is rubbed.
• the toner is liable to attach to the surface of a photoconductive material, or to the surfaces of carrier particles when such a toner is used for a two-component type developer. This results in deterioration and changes in the characteristics of the carrier.
• a crystalline resin such as polyethylene is used as a main binding resin for a toner, the producibility of the toner is reduced and a toner having stable characteristics is not obtained since it is difficult to control the degree of crystallization and the crystal form.
• Japanese published Patent Applications 75033/73 and 78931/73 propose a material designed to meet the above requirements by using a block copolymer composed of hard and soft resins.
• the amount of the soft component is increased to the extent necessary to impart sufficient pressure deformability to the toner, grinding of the toner becomes difficult when preparing a toner powder by a kneading and grinding method.
• a toner powder is prepared by a spray drying method, this difficulty does not occur since a grinding step is unnecessary.
• liquid preparation becomes difficult and it is difficult to impart both a good fixing property and anti-blocking property to the toner obtained.
• a multi-phase polymer such as a block copolymer or a graft copolymer
• the morphology of the toner is greatly influenced by a slight change in the production conditions and the properties of raw materials, resulting in great changes in the characteristics of the toner.
• Japanese published Patent Application 87042/76 discloses an attempt to improve the pressure fixibility of a toner by blending a crystalline resin such as polyethylene wax as a main component with a small amount of material such as a vinylic resin. Hower, since a crystalline resin is used as the main binding resin, there exist the above-mentioned difficulties which are specific to the crystalline resin.
• the present invention aims at producing a developer composition having an excellent pressure-fixing property.
• the present invention provides a developer composition
• a developer composition comprising (A) a resinous material having a polar fuctional group and a glass transition temperature below 0°C, and (B) a resinous material having a glass transition temperature above 40°C, which is chemically incompatible with material (A).
• Material (B) has a polar functional group capable of interacting with the polar functional group of material (A).
• Materials (A) and (B) are indispensable components for the toner of this invention.
• material (A) an olefinic polymer having a hydroxy group, a carboxyl group or a carbonyl group and as material (B) a styrenic polymer or a polyester resin having a hydroxy group, a carboxyl group or a dialkylamino group.
• the binding resinous material (A) in the developer composition of the present invention includes those having a glass transition temperature below 0°C, preferably below -30°C.
• Material (A) is selected from resinous materials which show plastic deformation or viscoelastic deformation with a pressure of less than about 2 kg/sq mm at room temperature and has a polar functional group.
• Polar functional groups of material (A) include a hydroxy group, a carbonyl group, a carboxy group, an epoxy group, a glicidyl group, a nitro group, a sulfonic acid group, an amino group, an amido group, a cyano group, an isocyanate group, a diazonium group, an aziridine group, an aldehyde group, an acid annydride, a methylol group, a thiol group, a mercapto group, a phosphoric acid group, and a halogen-containing group.
• These functional groups may be substituted by a group such as a methyl group, ethyl group, phenyl group or may have an ether linkage, ester linkage, etc.
• a hydroxy group, a carboxyl group and a carbonyl group are preferred, because they are very stable, have no deleterious effect on the characteristics of a toner, and have a large interaction with material (B).
• the resinous material (A) which has a polar functional group and which is capable of being deformed by pressure at normal temperature may be synthetic or natural resinous material.
• examples of such materials include higher fatty acids (e.g. stearic acid, oleic acid, etc.,) and derivatives therof (e.g.
• fatty acid amides fatty acid amides
• chlorinated paraffin chlorinated polyethylene, chlorinated polypropylene, oxidized polyethylene, polypropylene oxide, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, organic acid graft polyethylene, rubber-like acrylic acid copolymer, polyvinyl acetate, polyvinyl butyral, silicone and modified resins thereof, polycarbonate, fluorinated rubber, fluorinated wax, nitrile rubber, chloroprene rubber, polyamide, polyester, polyether, polyurethane, and polyalkyd.
• oxidized polyethylene, ethylene-acrylic acid copolymer and organic acid graft polyethylene which have a hydroxy group, a carboxyl group or a carbonyl group are particularly preferred for material (A).
• Binding resinous material (B) in the developer composition of the present invention can be selected from natural and synthetic resinous materials having a glass transition temperature above 40°C, more preferably 60-80 o C, and having a polar functional group as defined for material (A).
• a hydroxy group, a carboxyl group and dialkylamino group are particularly preferred as the polar functional group of material (B).
• styrene-acrylic acid copolymer, epoxy resin, phenol resin, polyester resin, etc. satisfying the aforesaid factors are preferably used since they meet many required parameters for toner.
• Material (A) is chemically incompatible with material (B) and the polar functional group of material (A) must interact with the polar functional group of material (B).
• Solubility is a suitable parameter for compatibility.
• the parameter of the solubility of material (A) is taken as ⁇ A and the parameter of the solubility of material (B) is taken as ⁇ B
• ⁇ A - ⁇ B is higher than about 0.5 it is defined as being incompatible.
• the solubility parameters of the resinous materials can be obtained by calculation. However, standard values which can be relied on are disclosed in "Polymer Handbook", 2nd Ed. (John Wiley & Sons).
• the interaction of the functional groups may involve (1) hydrophobic bonding, (2) electrostatic bonding, (3) hydrogen bonding, (4) charge transfer bonding, and (5) covalent bonding interactions.
• the interactions polar functional groups is important in this invention, the interaction of (2) to (5) are of greater importance.
• materials (A) and (B) are possible in this invention.
• R 1 and R 2 which may be the same or different, each represents an alkyl group (e.g., methyl, ethyl), as material (B).
• R 1 and R 2 which may be the same or different, each represents an alkyl group (e.g., methyl, ethyl), as material (B).
• R 1 and R 2
• the acid value is higher than 5 in both materials (A) and (B).
• Other polar group contents are similar in this regard.
• considerable care must be taken so that the content of the functional group is not too high. If the content gets too high, the interaction or reaction between the same kinds of molecules or different kinds of molecules as well as the intramolecular interaction or reaction become too strong. This can cause difficulties.
• a resin having an acid value of from about 10 to about 100 is preferred. The acid value is shown by the number of milligrams of potassium hydroxide necessary for neutralizing the acid contained in one gram of the resin.
• the present invention involves introducing a polar functional group into each of two resinous materials (A) and (B) which are incompatible with each other and have largely different physical and chemical properties, whereby materials (A) and (B) interact with each other.
• materials (A) and (B) interact with each other.
• the effects and merits of the present invention are briefly explained below.
• the toner must be constructed so that it exhibits these properties independently in each step of the image- forming processes.
• resin materials having different properties are made to adopt a proper multi-phase structure.
• the mixture obtained cannot exhibit the individual different properties of each resinous material.
• the mixture will meet certain of the various required parameters.
• the heterogeneous interface between them frequently reduces the properties of the toner.
• the interaction in this case may be a secondary bonding type of interaction such as hydrogen bonding, electrostatic bonding or alternatively may be a covalent bonding type of interaction such as grafting or crosslinking. It has also been found that when secondary bonding takes place, the stabilization in multi-phase dispersion structure not only facilitates the control of electric characteristics and mechanical properties, but also strengthens the shearing stress and shearing time reliance of the mechanical properties of the toner, which are advantageous because the resulting fixed toner image is free of smudges or smears even when rubbed.
• material (B), which is the hard component, having a glass transition temperature above 40°C be contained in the range of 5-95% by weight, preferably 10-80% by weight, more preferably 35-65% by weight, based on the total weight of the resinous materials.
• the toner further contains a resinous material additional to materials (A) and (B)
• resinous material having good compatibility with material (A)
• the additional material is a soft component having a glass transition temperature below 0°C
• material (B) if the additional material is a hard component having a glass transition temperature above 40°C.
• the proportion of the total soft components containing material (A) be 5-50% by weight of the resinous materials, and the proportion of the total hard components containing material (B) be 50-95% by weight.
• the toner may contain various kinds of additives such as coloring agents.
• useful coloring agents used in this invention include carbon black, magenta, yellow, cyan series pigments as well as Nigrosine, Fast Blue and other dyes.
• various kinds of magnetic powder can be included in the toner.
• the amount of magnetic powder in the toner depends upon various factors such as the conditions of the development process, but generally in the range of 20-80% by weight based on the total weight of the toner.
• the magnetic toner is preferably adjusted to have an electric resistance of 10 12 to 10 16 ohm. cm in view of its transferring and developing properties.
• the magnetic powder is preferably added in an amount of 30-60% by weight based on the total weight of the toner.
• useful magnetic powder include metals such as iron, cobalt, nickel, and alloys and oxides of these metals.
• Fe 3 0 4 , -Fe203, cobalt-doped iron oxide, ferrite powders such as powders of MnZn ferrite, etc. are preferably used.
• Such magnetic powders may be granular form or acicular form depending on the application of the toner, and the size of the powders is generally from 0.01 to 2u. Furthermore, these magnetic powders may be treated on their surfaces with a surface active agent or a fatty acid-, silane- or titanate-series coupling agent before being used.
• the toners may further contain materials such as plasticizers, granular or fibrous organic or inorganic reinforcing fillers, extenders, antioxidants, foaming agents, ionic or nonionic surface active agents.
• an external additive may be used in combination with the toners.
• useful external additives include long chain fatty acids (e.g.
• stearic acid and amides or metal salts thereof, fine powders of molybdenum disulfide, carbon black, graphite, fluorinated graphite, silicon carbide, boron nitride, silica, aluminum oxide, titanium dioxide, zinc oxide, fine powders of fluorine resins, polycyclic aromatic compounds, wax-like materials, and fine powders of crosslinked or non-crosslinked resins.
• These additives are usually solid fine particles having a low surface energy, below 30 ⁇ N/mm in critical surface tension or having a smooth surface which is below 0.1 in friction coefficient.
• the additives may also be comprised of fine particles having non-tackiness and some abrasive property. However the additives are not restricted to any such materials.
• these external additives may be fixed on the surface of toner powders by a hot blast method or otherwise.
• the developer composition of this invention can be produced by any conventional methods for example, a method comprising fusing whole components, kneading and grinding, a method comprising mixing the binding resinous materials in the form of solution followed by fusing whole components, kneading and grinding, or a spray drying method.
• the molecular weight of the hard components including material (B) is preferably controlled so as to make the composition of the particle surface of the developer composition uniform. By controlling the number average molecular weight to about 1000-30 000, the ground interfaces can selectively become a hard component phase containing component (B).
• the particle sizes of the toner are generally 1-50p, preferably 5-30N.
• the particle sizes may be controlled by classification if necessary.
• the developer composition of this invention There is no particular restriction regarding the form of the developer composition of this invention.
• the developer composition When the developer composition is used as a toner for a two-component developer, after controlling the static property of the toner with a static controlling agent, the toner is used as a mixture thereof with a carrier material such as an iron powder.
• the developer composition of this invention can also be used as magnetic toner for a one-component developer by mixing the developer composition with a magnetic powder as described above.
• it is used as a magnetic toner it is possible to develop not only electrostatic latent images but also magnetic latent images.
• the developer composition of this invention shows excellent fixibility with only the application of pressure.
• the composition of this invention can be securely fixed by heat and pressure or by heating or by the use of a solvent.
• a polystyrene resin Polystyrene resin
• Evaflex 220 made by Mit
• the toner was mixed with 0.8% by weight fine powder of hydrophobic colloidal silica. After further mixing a carrier iron powder having particle size of about 80 um was added. The carrier/toner weight ratio was then adjusted to about 100/5. An image test was then performed using a Xerox (registered trademark) 2300 copying machine. In addition, fixing was performed using a pressure fixing apparatus composed of three metallic rolls at a line pressure of 2.5 kg/mm. The initial image quality was relatively good, but when 5,000 copies were made by repeating the operation, the image density was reduced and background fog increased greatly.
• Fixing was good in appearance but when the images were rubbed, the images came off partially, and fingers and clothes were readily stained.
• the toner was also found to be inferior in powder fluidity and antiblocking property at high temperature.
• the toner was mixed with 0.5% by weight carbon black and a copy test was performed using a one-component-type copying machine.
• a copy test was performed using a one-component-type copying machine.
• good development and good transferring property were shown under ordinary circumstances, but when 2000 copies were continuously made, a roughness of image was observed.
• the cause is considered to be that since filming of the toner onto the photoconductive material occurred and the development and transfer were carried out selectively, the particle sizes of the toner changed with time.
• the properties of the rough particle portion of the loner were compared with those of the fine powder portion, they differed from each other and it is considered that the distribution of the composition and multi-phase dispersion structure of the toner were broad and the toner was unstable.
• the pressure fixing of the toner at a line pressure of 2.5kg/mm showed the same defects as in Example 1.
• a toner having a mean particle size of 14 um was prepared by the same manner as in Example 1 using the following components;
• a developer was prepared by mixing the toner with 0.8% by weight fine powder of hydrophobic colloidal silica and further mixing with an iron carrier powder having a particle size of about 80 um in such manner that the carrier/toner weight ratio became about 100/5 and a copy test was performed as in Example 1.
• 20,000 copies were made by repeating the operation, images were good. Furthermore, no change with the passage of time was observed.
• the pressure-fixing property was evaluated at a line pressure of 2.0 kg/m, 2.5 kg/mm and 3.0 kg/mm and each case showed good fixing property. It is believed that a stable and proper multi-phase dispersion structure was formed by the interaction of the functional group of the styrenic copolymer and that of the modified ethylene resin. Also, it is considered that since the surface composition of the toner particle was mainly composed of the styrenic resin and was uniform, the charge distribution was narrow. This was also confirmed by the analytical result by ESCA, etc.
• a magnetic toner having a mean particle size of 15 um was prepared in the same manner as in Example 2 using the following components;
• the toner was mixed with 0.5% by weight carbon black and when a copy test was performed using a one-component copying machine, all good development and transferring property were shown under all circumstances. Also, when 10,000 copies were continuously made, no change in image quality was observed. When a pressure fixing was applied at a line pressure of 2.5kg/mm, the image was strongly fixed. When the fixed image was subjected to a friction test using an adhesive tape or rubbed by a finger, the image did not come off or stain clothes.
• a toner having a mean particle size of 17 um was prepared in the manner as in the other examples from the following composition;
• the toner was mixed with 0.4% by weight carbon black and 0.2% by weight silica powder.
• a copy test was performed as in Example 6, a good pressure fixing level and good image quality was obtained.
• a styrenic copolymer produced by copolymerizing styrene, methyl methacrylate, butyl methacryl
• the toner was mixed with 0.2% by weight zinc stearate and 0.6% by weight fine powder of hydrophobic silica, and a copy test was performed using a one-component copying machine. When 10,000 copies were made by repeating the operation, the development, transferring property and image quality were good and the pressure fixing at a line pressure of 3.0 kg/mm was very excellent.
• the toner of the present invention provides an excellent toner image, free of background fogs, with high resolution even after 5,000 reproductions and is thoroughly fixed by the application of pressure so that, in contrast to a conventional toner for pressure fixing, the fixed toner image does not smudge or adhere to a finger when rubbed. Further the fixed toner image does not transfer to a back surface of a sheet in contact with the image during storage. Furthermore, the toner transfer rate of the toner of the present invention is not so decreased even at an increased humidity.
• the magnetic toner of the present invention has a markedly stable toner transfer rate as compared to a conventional magnetic toner.

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• Developing Agents For Electrophotography (AREA)

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• 1981
  • 1981-05-15 JP JP56072201A patent/JPS57188045A/ja active Granted
• 1982
  • 1982-05-14 DE DE8282302468T patent/DE3273295D1/de not_active Expired
  • 1982-05-14 CA CA000403032A patent/CA1183033A/en not_active Expired
  • 1982-05-14 EP EP19820302468 patent/EP0066395B1/de not_active Expired

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