EP0686883A1 - Toner zur Entwicklung elektrostatischer Bilder, Bilderzeugungsverfahren und Prozesskartusche - Google Patents

Toner zur Entwicklung elektrostatischer Bilder, Bilderzeugungsverfahren und Prozesskartusche Download PDF

Info

Publication number
EP0686883A1
EP0686883A1 EP95107141A EP95107141A EP0686883A1 EP 0686883 A1 EP0686883 A1 EP 0686883A1 EP 95107141 A EP95107141 A EP 95107141A EP 95107141 A EP95107141 A EP 95107141A EP 0686883 A1 EP0686883 A1 EP 0686883A1
Authority
EP
European Patent Office
Prior art keywords
toner
long
chain alkyl
denotes
image forming
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP95107141A
Other languages
English (en)
French (fr)
Other versions
EP0686883B1 (de
Inventor
Koichi Tomiyama
Takaaki Kohtaki
Manabu Ohno
Makoto Unno
Yushi Mikuriya
Nobuyuki Okubo
Tadashi Doujo
Shunji Suzuki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Publication of EP0686883A1 publication Critical patent/EP0686883A1/de
Application granted granted Critical
Publication of EP0686883B1 publication Critical patent/EP0686883B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • G03G9/097—Plasticisers; Charge controlling agents
    • G03G9/09783—Organo-metallic compounds
    • 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
    • G03G9/08775—Natural macromolecular compounds or derivatives thereof
    • G03G9/08782—Waxes
    • 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
    • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08759—Polyethers
    • 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
    • G03G9/08795—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775 characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants
    • 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
    • G03G9/09—Colouring agents for toner particles
    • G03G9/0906—Organic dyes
    • G03G9/091—Azo dyes
    • 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
    • G03G9/097—Plasticisers; Charge controlling agents
    • G03G9/09733—Organic compounds
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
    • G03G15/0208—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices by contact, friction or induction, e.g. liquid charging apparatus
    • G03G15/0216—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices by contact, friction or induction, e.g. liquid charging apparatus by bringing a charging member into contact with the member to be charged, e.g. roller, brush chargers
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
    • G03G21/0005—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge for removing solid developer or debris from the electrographic recording medium
    • G03G21/0011—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge for removing solid developer or debris from the electrographic recording medium using a blade; Details of cleaning blades, e.g. blade shape, layer forming
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
    • G03G21/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements
    • G03G21/18—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements using a processing cartridge, whereby the process cartridge comprises at least two image processing means in a single unit
    • G03G21/1803—Arrangements or disposition of the complete process cartridge or parts thereof
    • G03G21/1814—Details of parts of process cartridge, e.g. for charging, transfer, cleaning, developing
    • 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
    • G03G9/0819—Developers with toner particles characterised by the dimensions of the 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

Definitions

  • the present invention relates to a toner, particularly a negatively chargeable toner, for developing electrostatic images in image forming methods, such as electrophotography, and electrostatic printing.
  • the present invention also relates to an image forming method and a-process cartridge using the toner.
  • Known developing methods for visualizing electrical latent images with a toner may include, e.g., the magnetic brush method described in U.S. Patent No. 2,874,063, the cascade developing method disclosed in U.S. Patent No. 2,618,552, the powder cloud method disclosed U.S. Patent No. 2,221,776, and a method using an electroconductive magnetic toner disclosed in U.S. Patent No. 3,909,258.
  • a sheet carrying a toner image to be fixed (hereinafter called “fixation sheet”) is passed through hot rollers, while a surface of a hot roller having a releasability with the toner is caused to contact the toner image surface of the fixation sheet under pressure, to fix the toner image.
  • fixation sheet a sheet carrying a toner image to be fixed
  • a surface of a hot roller having a releasability with the toner is caused to contact the toner image surface of the fixation sheet under pressure, to fix the toner image.
  • a fixing apparatus comprising a heating member and a pressing member which is disposed opposite to the heating member and presses a recording medium (such as paper) to contact the heating member via a film.
  • a recording medium such as paper
  • copied images appear clearer because of an edge effect of attracting an increased amount of toner so that clear line images can be retained in case where a maximum density of ca. 1.30 is attained at a solid image part which is less affected by the edge effect.
  • the density gradation characteristic is liable to be remarkably affected by the saturation charge and the charging speed of a developer used.
  • the saturation charge is appropriate for the developing conditions
  • a developer showing a slow charging speed provides a low maximum image density, thus generally thin and blurred images in the initial stage of copying.
  • the maximum image density is ca. 1.3, as described above, thus being able to obviate an adverse effect of the slow chargeability.
  • the initial copy image density is increased if the saturation charge is increased.
  • the charge of the developer is gradually increased to finally exceed an appropriate charge for development, thereby resulting in a lower copy image density.
  • no problem occurs in line images if the maximum image density is ca. 1.3
  • a toner for developing electrostatic images may generally contain a dye called a charge control agent for controlling the chargeability of the toner.
  • a charge control agent for controlling the chargeability of the toner.
  • chromium complex compounds have been principally used.
  • JP-A 60-170864 describes that, among such chromiun complex compounds, those having a good mutual solubility with a binder resin show a uniform negative chargeability and provide clear copy images but are liable to be accompanies with difficulties, such remaining of a toner residue on a photosensitive member due to cleaning failure and filming, and those being insoluble within a binder resin (particularly in a polyester resin) show good chargeability and also good anti-filming characteristic.
  • a metal complex salt compound insoluble or incompatible with a binder resin shows a poor dispersibility. Accordingly, when a toner containing such a metal complex salt compound is formulated into fine particles, the toner is liable to be charged excessively particularly in a low-humidity environment, thus leading to for or a density lowering. This is because a fine particle size fraction and a coarse particle size fraction formed through a pulverization step of toner production are caused to have remarkably different contents (weight ratios) of the charge control agent (i.e. so-called localization of a charge control agent), so that toner particles are caused to have different chargeabilities.
  • the charge control agent i.e. so-called localization of a charge control agent
  • JP-A 61-155464 and JP-A 62-177561 have proposed an azo-type iron complex as a charge control agent showing good dispersibility within a binder resin.
  • a toner containing the azo-type iron complex is, however, accompanied with difficulties, such as a slow rate of electrification and a lowering in image density after a long period of standing or in a high humidity environment.
  • a smaller particle size at most 9 ⁇ m in terms of a weight-average particle size (diameter) is recommended for providing high-quality images.
  • a small particle size toner is liable to have a remarkably high charge under a low-humidity condition and cause difficulties, such as thinning of line images, a lowering in image density and occurrence of reversal potential fog caused by a toner charged to an opposite polarity due to charging failure on a developer-carrying member, such as a developing sleeve, due to the copresence of the excessively charged toner.
  • JP-A 1-306862 has proposed a silicone resin-coated carrier which has a high chargeability-imparting effect
  • JP-A 2-153362 has proposed a developing apparatus including an improved toner layer thickness-regulating member and an improved toner replenishment-assisting member.
  • the developing performance of the toner is retained by charge-imparting or -assisting members and it is difficult to retain good image quality for a long period due to deterioration or soiling of the charge-imparting or -assisting member.
  • An object of the present invention is to provide a toner for developing electrostatic images having solved the above-mentioned problems and capable of retaining a high-quality image forming performance for a long period.
  • An object of the present invention is to provide a toner having a good dispersibility of a charge control agent and a uniform chargeability, capable of retaining a high image density for a long period and capable of providing images free from fog and with a high resolution.
  • Another object of the present invention is to provide a toner which can be quickly charged and can provide good toner images similarly as before standing even after standing for a long period or in a high-humidity environment.
  • Another object of the present invention is to provide a toner which can provide high-quality images without using a charge-assisting member.
  • Another object of the present invention is to provide a fine particle size toner which can provide satisfactory developed images for a long period under various environmental conditions even in case of providing high-resolution developed images.
  • Another object of the present invention is to provide a toner which allows re-utilization of fine powder and coarse powder by-produced in the classification step in toner production.
  • Another object of the present invention is to provide a toner highly suitably adapted to an electrophotographic process not adversely affecting a photosensitive member or a developer-carrying member.
  • a further object of the present invention is to provide an image forming method and a process cartridge using such a toner as described above.
  • a toner for developing electrostatic images comprising:
  • an image forming method comprising: a charging step of supplying a voltage to a charging means in contact with a member to be charged to charge the member to be charged, a step of forming an electrostatic image on the charged member to be charged, a developing step of developing the electrostatic image with a toner as described above to form a toner image on the member to be charged, a transfer step of transferring the toner image to a transfer-receiving material directly or via an intermediate transfer member, and a fixing step of fixing the toner image onto the transfer-receiving material.
  • a process-cartridge comprising at least a developing means and a photosensitive member, the developing means and the photosensitive member being integrated into a cartridge which is detachably mountable to a main body of an image forming apparatus, wherein the developing means contains a toner as described above.
  • Figure 1 is a schematic illustration of an image forming apparatus used in Examples of the present invention.
  • Figure 2 is an exploded perspective view of essential parts of a fixing apparatus used in Examples of the invention.
  • Figure 3 is an enlarged sectional view of a fixing apparatus including a film in a non-driven state used in Examples of the present invention.
  • Figure 4 is a partial illustration of a checker pattern for evaluating the developing performance of a toner.
  • Figure 5 is a schematic illustration of an embodiment of the process-cartridge according to the present invention.
  • An azo-type iron complex when used as a charge control agent for an electrophotographic toner, provides a toner which shows an insufficient charging speed under a high-humidity condition and fails to provide a sufficient image density at an initial stage or a long period of standing under a high-humidity condition. Under a low-humidity condition, in a long period of continual use, the toner is liable to cause an accumulation of an excessive triboelectric charge (charge-up), thus resulting in images with a low image density and noticeable fog.
  • a chromium or aluminum complex compound insoluble in a binder resin alleviates the above-mentioned problems and has been therefore widely used.
  • a toner using such a chromium or aluminum complex compound is accompanied with a problem that classified fine powder and classified coarse powder thereof cannot be readily re-utilized. This is because the chromium or aluminum complex compound is contained in different weight ratios in the classified fine powder, classified medium powder (used as a toner) and classified coarse powder, so that a toner produced by re-utilization of the classified fine powder and the classified coarse powder is liable to cause a lowering in image density and fog during a long period of continual use in a low-humidity environment.
  • an azo-type iron complex compound shows little localization in classified powders and that a binder containing an azo-type chromium complex compound insoluble in a binder resin shows a good developing performance, whereby we have succeeded in improving the charge controllability of an azo-type iron complex compound while retaining the non-localizability of the azo-type iron complex compound, by forming micro-domains (aggregations) of the azo-type iron complex compound in toner particles.
  • an azo-type iron complex compound is accomplished by the presence of a long-chain alkyl compound in toner particles. This is considered because the OH groups or carboxyl groups in the long-chain alkyl compound respectively form an associated state and, under the influence of the associations, the azo-type iron complex compound forms microdomain. As a result, the azo-type iron complex compound can be provided with an improved charge controllability while maintaining the non-localizability.
  • the localization of an azo-type metal complex in classified fine powder, classified medium powder (used as a toner) and classified coarse powder resultant after a classification step in a toner production process using the azo-type metal complex is evaluated in the following manner.
  • the localization characteristic of the metal complex is evaluated by factors (ratios): OD F /OD M and OD C /OD M , wherein OD F denotes an absorbance of a filtrate obtained from classified fine powder, OD M denotes an absorbance of a filtrate obtained from classified medium powder and OD C denotes an absorbance of a filtrate obtained from classified coarse powder.
  • An azo-type iron complex compound having cations consisting solely of ammonium ions tends to provide a toner showing an image density which slowly increases after standing in a high-humidity environment.
  • an azo-type iron complex compound having cations consisting only of protons or alkali metal ions tends to provide a toner showing a low image density in a high-humidity environment.
  • the azo-type iron complex compound used in the toner according to the present invention may preferably have a solubility in methanol of 0.1 - 8 g/100 ml, more preferably 0.3 - 4 g/100 ml, further preferably 0.4 - 2 g/100 ml.
  • the charge control agent (azo-type iron complex compound) shows a low dispersibility in the toner even if the long-chain alkyl compound is used in combination, thus providing a toner which has an unstable triboelectric chargeability and is liable to cause image fog and scattering.
  • the solubility exceeds 8 g/100 ml
  • the toner performances are liable to be affected by the temperature and humidity during a long period of standing in a high temperature - high humidity environment, so that the toner chargeability is impaired and it becomes difficult to obtain a sufficient image density.
  • the charge control agent may preferably be used in a proportion of 0.2 - 5 wt. parts per 100 wt. parts of the binder resin.
  • the solubility of the charge control agent may be measured in the following manner.
  • the azo-type iron complex compound used in the present invention has a structure represented by the following general formula (4): wherein X1 and X2 independently denote hydrogen atom, lower alkyl group, lower alkoxy group, nitro group or halogen atom; m and m' denote an integer of 1 - 3; R1 and R3 independently denote hydrogen atom, C1 ⁇ 18 alkyl or alkenyl, sufonamide, mesyl, sulfonic acid group, carboxy ester group, hydroxy, C1 ⁇ 18 alkoxy, acetylamino, benzoylamino or halogen atom; n and n' denote an integer of 1 - 3; R2 and R4 denote hydrogen atom or nitro group; and A+ denotes a cation including 75 - 98 mol. % of ammonium ion and another ion selected from the group consisting of hydrogen ion, sodium ion, potassium iron and mixtures thereof.
  • the above azo-type iron complex which is suitably used as a negative charge control agent may be synthesized according to a known process.
  • the negative charge control agent may be used singly or in combination of two or more species or in combination with another negative charge control agent.
  • azo-type iron complex represented by the above formula may include those having structures as shown below wherein A ⁇ denotes the same meaning as defined above:
  • the azo-type ion complex may preferably be used in an amount of 0.1 - 10 wt. parts, more preferably 0.1 - 5 wt. parts, per 100 wt. parts of the binder resin.
  • the long-chain alkyl compound used in the present invention may be represented by the following formula (1), (2) or (3). wherein x denotes an average value in the range of 35 - 150; z denotes an average value in the range of 1 - 5, and R denotes H or an alkyl group having 1 - 10 carbon atoms.
  • the long-chain alkyl compound of the above formulae may for example be produced as follows. Ethylene is polymerized in the presence of a Ziegler catalyst and, after the polymerization, oxidized to provide an alkoxide of the catalyst metal and polyethylene, which is then hydrolyzed to provide an objective long-chain alkyl compound of formula (1). By reacting the long-chain alkyl alcohol of formula (1) with an epoxy group-containing substance, it is possible to obtain a long-chain alkoxy alcohol of formula (2).
  • the thus prepared long-chain alkyl alcohols have little branching and a sharp molecular weight distribution and are suitably used in the present invention. wherein y denotes an integer of 35 - 150.
  • the long-chain alkyl compound of formula (3) may be obtained by oxidizing the long-chain alkyl compound of formula (1).
  • x and y may preferably be 35 - 150. If x and y are below 35, the resultant toner is liable to cause melt-sticking onto the photosensitive member or a lower storage stability. If x and y are larger than 150, the above-mentioned contribution to toner chargeability (i.e., promoting the formation of microdomains of the azo-type iron complex) is lowered, thus being unsuitable for accomplishing the object of the present invention.
  • z is preferably at most 5. If z is larger than 5, the resultant toner is liable to cause melt-sticking onto the photosensitive member.
  • R is H or a C1 - C10 alkyl group.
  • the long-chain alkyl compound used in the present invention may suitably be a mixture of compounds having different molecular weights and can further contain at most 30 wt. %, preferably at most 25 wt. % of hydrocarbon compounds free from functional groups such as hydroxyl and carboxyl group as by-produced through the above-mentioned production processes of the compounds of the formulae (1) - (3).
  • the long-chain alkyl compound may preferably have a number-average molecular weight (Mn) of 150 - 2500, a weight-average molecular weight (Mw) of 250 - 5000, and an Mw/Mn ratio of at most 3.
  • the long-chain alkyl compound of formula (1) or (2) used in the present invention may preferably have an OH value of 2 - 150 mgKOH/g, more preferably 10 - 120 mgKOH/g. If the long-chain alkyl compound has an OH value below 2 mgKOH/g, the dispersibility thereof in the binder resin is lowered to result in ununiform toner chargeability leading to a density decrease, fog, and inferior image quality in copy images.
  • the long-chain alkyl compound has an OH value exceeding 150 mgKOH/g
  • the localization of the OH group charge density is increased to exceed the charge density localization of the OH groups in the binder resin, so that copy images in the initial state of image formation are liable to have a low density and a poor image quality.
  • the density is liable to be lowered gradually on continuation of copying.
  • the OH value exceeds 150 mgKOH/g
  • the long-chain alkyl compound is caused to contain a large amount of low-molecular weight molecules so that the resultant toner is liable to cause a melt-sticking onto the photosensitive member and lower the storage stability.
  • the long-chain alkyl compound of formula (3) used in the present invention may preferably have an acid value of 2 - 150 mgKOH/g, more preferably 5 - 120 mgKOH/g. If the long-chain alkyl compound has an acid value below 2 mgKOH/g, the dispersion thereof in the binder resin becomes worse, thereby resulting in inferior image qualities of copy images. Further, as the carboxyl groups do not sufficiently associate each other, the environmental characteristic is liable to be impaired. Further, the resultant toner is liable to show a low charging velocity, to result in a lower density at the initial stage of copying.
  • the acid value of the long-chain alkyl compound exceeds 150 mgKOH/g, it contains a large amount of low-molecular weight molecules, the resultant toner is liable to cause melt-sticking onto the photosensitive member and lower the storage stability.
  • the long-chain alkyl compounds when used singly, may preferably be contained in an amount of 0.1 - 30 wt. parts, particularly 0.5 - 20 wt. parts, per 100 wt. parts of the binder resin.
  • the total amount thereof may preferably be 0.1 - 30 wt. parts, more preferably 0.5 - 20 wt. parts, per 100 wt. parts of the binder resin.
  • the toner according to the present invention it is preferred for the toner according to the present invention to contain 3 - 90 % by number of toner particles having a particle size of 5 ⁇ m or smaller. Hitherto, it has been considered difficult to control the charge imparted to toner particles of 5 ⁇ m or smaller. Further, such fine toner particles are considered to impair the fluidity of the toner, soil the carrier and developing sleeve, cause cleaning failure and filming onto the drum and scatter to soil the interior of an image forming apparatus. Thus, it has been considered necessary to remove or decrease toner particles of 5 ⁇ m or smaller.
  • toner particles of 6.35 - 10.08 ⁇ m constitute 1 - 80 % by number and the toner has a weight-average particle size of 4.0 - 10 ⁇ m, more preferably 4.5 - 9.0 ⁇ m.
  • Toner particles of 5 ⁇ m or smaller are able to strictly cover and faithfully reproduce an electrostatic image, but an electrostatic image per se has a higher electric field intensity at the peripheral edge than the middle or central portion.
  • toner particles are attached to the central portion in a smaller thickness than to the peripheral part, so that the inner part is liable to be thin in density.
  • this problem can be solved to provide a clear image by using toner particles of 6.35 - 10.08 ⁇ m in a proportion of 1 - 80 % by number.
  • toner particles of 6.35 - 10.08 ⁇ m are supplied to an inner part having a smaller intensity than the edge of a latent image presumably because they have a moderately controlled charge relative to toner particles of 5 ⁇ m or smaller, thereby to compensate for the less coverage of toner particles and result in a uniform developed image.
  • a sharp image having a high density and excellent in resolution and gradation characteristic can be attained.
  • the toner having a particle size distribution satisfying the relationship in combination with the other characteristic features according to the present invention accomplishes a better developing performance with respect to a digital latent image composed of minute spots.
  • N a large N/V value is understood to mean that a large proportion of particles smaller than 5 ⁇ m are present with a broad particle size distribution
  • a small N/V value is understood to mean that particles having a particle size in the neighborhood of 5 ⁇ m is present in a large proportion and particles smaller than that are present in a small proportion.
  • a further better thin-line reproducibility and high resolution in a large quantity of copying or printing are accomplished when the N/V is in the range of 1.0 - 7.45, N is in the range of 5 - 90 and the above formula relationship is satisfied.
  • Toner particles of 12.7 ⁇ m or larger are suppressed to be not more than 2.0 % by volume. The fewer, the better.
  • the particle size distribution of the toner used in the present invention is described more specifically below.
  • Toner particles of 5 ⁇ m or smaller may be contained in a proportion of 5 - 90 % by number, further preferably 9 - 75 % by number, of the total number of particles. If the content of the toner particles of 5 ⁇ m or smaller is below 5 % by number, a portion of the toner particles effective for providing a high image quality is few and particularly, as the toner is consumed during a continuation of copying or printing-out, the effective component is preferentially consumed to result in an awkward particle size distribution of the toner and gradually deteriorates the image quality.
  • the content of the particles in the range of 6.35 - 10.08 ⁇ m is 1 - 80 % by number, further preferably 5 - 70 % by number. Above 80 % by number, the image quality becomes worse, and excess of toner coverage is liable to occur, thus resulting in a lower thin-line reproducibility and an increased toner consumption. Below 5 % by number, it becomes difficult to obtain a high image density in some cases.
  • V may preferably be 0.5 - 70 % by volume.
  • the k value may preferably be 3 - 12, more preferably 4 - 10.
  • toner particles of 5.0 ⁇ m or below are insufficient, and the resultant image density, resolution and sharpness decrease.
  • fine toner particles in a toner which have conventionally been considered useless, are present in an appropriate amount, they are effective for achieving closest packing of toner in development and contribute to the formation of a uniform image. Particularly, these particles fill thin-line portions and contour portions of an image, thereby to visually improve the sharpness thereof.
  • k > 12 an excess of fine powder is present, whereby the balance of particle size distribution can be disturbed during successive copying or print-out, thus leading to difficulties such as a somewhat lower image density and filming.
  • the amount of toner particles having a particle size of 12.7 ⁇ m or larger should be 2.0 % by volume or smaller, preferably 1.0 % by volume or smaller, more preferably 0.5 % by volume or smaller. If the above amount is larger than 2.0 % by volume, these particles are liable to impair thin-line reproducibility.
  • the toner used in the present invention may have a weight-average particle size of 4 - 10 ⁇ m, more preferably 4.5 - 9 ⁇ m. This value cannot be considered separately from the above-mentioned factors. If the weight-average particle size is below 4 ⁇ m, the toner is liable to cause soiling of the interior of an apparatus with scattered toner, a lowering in image density in a low-humidity environment and cleaning failure of the photosensitive member. If the weight-average particle size exceeds 9 ⁇ m, a minute spot of 100 ⁇ m or smaller cannot be developed with a sufficient resolution and noticeable scattering to non-image part is observed, thus being liable to provide inferior images.
  • binder resin used in the toner of the present invention may include polyester resins, vinyl resins and epoxy resins.
  • polyester resins or vinyl resins may preferably be used in view of charging characteristic and fixing characteristic.
  • a polyester resin preferably used in the present invention may have a composition that it comprises 45 - 55 mol. % of alcohol component and 55 - 45 mol. % of acid component.
  • Examples of the alcohol component may include: diols, such as ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, bisphenols and derivatives represented by the following formula (A): wherein R denotes an ethylene or propylene group, x and y are independently a positive integer of at least 1 with the proviso that the average of x+y is in the range of 2 - 10; diols represented by the following formula (B): wherein R' denotes -CH2CH2-, x' and y' are a positive integer of at least 1 with the proviso that the average of x'+y' is in
  • Examples of the dibasic acid constituting at least 50 mol. % of the total acid may include benzenedicarboxylic acids, such as phthalic acid, terephthalic acid and isophthalic acid, and their anhydrides; alkyldicarboxylic acids, such as succinic acid, adipic acid, sebacic acid and azelaic acid, and their anhydrides; C6 - C18 alkyl or alkenylsubstituted succinic acids, and their anhydrides; and unsaturated dicarboxylic acids, such as fumaric acid, maleic acid, citraconic acid and itaconic acid, and their anhydrides.
  • benzenedicarboxylic acids such as phthalic acid, terephthalic acid and isophthalic acid, and their anhydrides
  • alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid and azelaic acid, and their anhydrides
  • An especially preferred class of alcohol components constituting the polyester resin is a bisphenol derivative represented by the above formula (A), and preferred examples of acid components may include dicarboxylic acids inclusive of phthalic acid, terephthalic acid, isophthalic acid and their anhydrides; succinic acid, n-dodecenylsuccinic acid, and their anhydrides, fumaric acid, maleic acid, and maleic anhydride.
  • the polyester resin may preferably have a glass transition temperature of 40 - 90 o C, particularly 45 - 85 o C, a number-average molecular weight (Mn) of 1,000 - 50,000, particularly 1,500 - 20,000, and a weight-average molecular weight (Mw) of 3x103 - 5x106, particularly 4x103 - 1.5x106.
  • Examples of a vinyl monomer for providing the vinyl resin may include: styrene; styrene derivatives, such as o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, and p-n-dodecylstyrene; ethylenically unsaturated monoole
  • Examples of a carboxy group-containing vinyl monomer may include: unsaturated dibasic acids, such as maleic acid, citraconic acid, itaconic acid, alkenylsuccinic acid, fumaric acid, and mesaconic acid; unsaturated dibasic acid anhydrides, such as maleic anhydride, citraconic anhydride, itaconic anhydride, and alkenylsuccinic anhydride; unsaturated dibasic acid half esters, such as mono-methyl maleate, mono-ethyl maleate, mono-butyl maleate, mono-methyl citraconate, mono-ethyl citraconate, mono-butyl citraconate, mono-methyl itaconate, mono-methyl alkenylsuccinate, monomethyl fumarate, and mono-methyl mesaconate; unsaturated dibasic acid esters, such as dimethyl maleate and dimethyl fumarate; ⁇ , ⁇ -unsaturated acids, such as acrylic acid, methacrylic acid
  • a hydroxyl group-containing vinyl monomer inclusive of acrylic or methacrylic acid esters, such as 2-hydroxyethyl acrylate, and 2-hydroxyethyl methacrylate; 4-(1-hydroxy-1-methylbutyl)styrene, and 4-(1-hydroxy-1-methylhexyl)styrene.
  • the vinyl resin may have a glass transition point of 45 - 80 o C, preferably 55 - 70 o C, a number-average molecular weight (Mn) of 2.5x103 - 5x104, and a weight-average molecular weight (Mw) of 1x104 - 1.5x106.
  • a mixture binder resin including a vinyl homopolymer ro copolymer, a polyester, polyester, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclichydrocarbon resin or aromatic petroleum resin, in addition to the above-mentioned binder resin.
  • the two or more resins may preferably have different molecular weights and may be mixed with each other in appropriate ratios.
  • the toner according to the present invention may be either a magnetic toner or a non-magnetic toner.
  • a magnetic toner it is preferred to use a magnetic material as described below.
  • Examples of the magnetic material contained in the insulating magnetic toner used in the present invention may include: iron oxides, such as magnetite, hematite, and ferrite; iron oxides containing another metal oxide; metals, such as Fe, Co and Ni, and alloys of these metals with other metals, such as Al, Co, Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W and V; and mixtures of the above.
  • the magnetic material may include: triiron tetroxide (Fe3O4), diiron trioxide ( ⁇ -Fe2O3), zinc iron oxide (ZnFe2O4), yttrium iron oxide (Y3Fe5O12), cadmium iron oxide (CdFe2O4), gadolinium iron oxide (Gd3Fe5O12), copper iron oxide (CuFe2O4), lead iron oxide (PbFe12O19), nickel iron oxide (NiFe2O4), neodymium iron oxide (NdFe2O3), barium iron oxide (BaFe12O19), magnesium iron oxide (MgFe2O4), manganese iron oxide (MnFe2O4), lanthanum iron oxide (LaFeO3), powdery iron (Fe), powdery cobalt (Co), and powdery nickel (Ni).
  • the above magnetic materials may be used singly or in mixture of two or more species.
  • Particularly suitable magnetic material for the present invention is fine powder
  • the magnetic material may have an average particle size (Dav.) of 0.1 - 2 ⁇ m, preferably 0.1 - 0.3 ⁇ m.
  • the magnetic material may preferably show magnetic properties when measured by application of 10 kilo-Oersted, inclusive of: a coercive force (Hc) of 20 - 150 Oersted, a saturation magnetization ( ⁇ s) of 50 - 200 emu/g, particularly 50 - 100 emu/g, and a residual magnetization ( ⁇ r) of 2 - 20 emu/g.
  • Hc coercive force
  • ⁇ s saturation magnetization
  • ⁇ r residual magnetization
  • the magnetic material may be contained in the toner in a proportion of 10 - 200 wt. parts, preferably 20 - 150 wt. parts, per 100 wt. parts of the binder resin.
  • the toner according to the present invention may optionally contain a colorant, inclusive of arbitrary pigments or dyes.
  • the pigment may include: carbon black, aniline black, acetylene black, Naphthol Yellow, Hansa Yellow, Rhodamine Lake, Alizarine Lake, red iron oxide, Phthalocyanine Blue, and Indanthrene Blue. It is preferred to use 0.1 - 20 wt. parts, particularly 1 - 10 wt. parts, of a pigment per 100 wt. parts of the binder resin.
  • dyes such as azo dyes, anthraquinone dyes, xanthene dyes, and methine dyes, which may preferably be used in an amount of 0.1 - 20 wt. parts, particularly 0.3 - 10 wt. parts, per 100 wt. parts of the resin.
  • Examples of the release agent may include: aliphatic hydrocarbon waxes, such as low-molecular weight polyethylene, low-molecular weight polypropylene, microcrystalline wax, and paraffin wax, oxidation products of aliphatic hydrocarbon waxes, such as oxidized polyethylene wax, and block copolymers of these; waxes containing aliphatic esters as principal constituents, such as carnauba wax, montanic acid ester wax, and partially or totally deacidified aliphatic esters, such as deacidified carnauba wax.
  • aliphatic hydrocarbon waxes such as low-molecular weight polyethylene, low-molecular weight polypropylene, microcrystalline wax, and paraffin wax, oxidation products of aliphatic hydrocarbon waxes, such as oxidized polyethylene wax, and block copolymers of these
  • waxes containing aliphatic esters as principal constituents such as carnauba wax, montanic acid ester wax, and partially or totally dea
  • the release agent may include: saturated linear aliphatic acids, such as palmitic acid, stearic acid, and montanic acid; unsaturated aliphatic acids, such as brassidic acid, eleostearic acid and parinaric acid; saturated alcohols, such as stearyl alcohol, behenyl alcohol, ceryl alcohol, and melissyl alcohol; polyhydric alcohols, such as sorbitol; aliphatic acid amides, such as linoleylamide, oleylamide, and laurylamide; saturated aliphatic acid bisamides, methylene-bisstearylamide, ethylene-biscaprylamide, and ethylene-biscaprylamide; unsaturated aliphatic acid amides, such as ethylene-bisolerylamide, hexamethylene-bisoleylamide, N,N'-dioleyladipoylamide, and N,N'-dioleylsebacoylamide, aromatic bisamides, such
  • the particularly preferred class of release agent in the present invention may include aliphatic hydrocarbon waxes because of good dispersibility within the binder resin (preferably one having an acid value of 5 - 50), thus providing not only a good fixability of the resultant toner but also a minimum abrasion of an organic photoconductor when used in combination with the toner according to the present invention.
  • the release agent preferably used in the present invention may include e.g., a low-molecular weight alkylene polymer obtained through polymerization of an alkylene by radical polymerization under a high pressure or in the presence of a Ziegler catalyst under a low pressure; an alkylene polymer obtained by thermal decomposition of an alkylene polymer of a high molecular weight; and a hydrocarbon wax obtained by subjecting a mixture gas containing carbon monoxide and hydrogen to the Arge process to form a hydrocarbon mixture and distilling the hydrocarbon mixture to recover a residue. Fractionation of wax may preferably be performed by the press sweating method, the solvent method, vacuum distillation or fractionating crystallization.
  • hydrocarbons having up to several hundred carbon atoms as obtained through synthesis from a mixture of carbon monoxide and hydrogen in the presence of a metal oxide catalyst (generally a composite of two or more species), e.g., by the Synthol process, the Hydrocol process (using a fluidized catalyst bed), and the Arge process (using a fixed catalyst bed) providing a product rich in waxy hydrocarbon, and hydrocarbons obtained by polymerizing an alkylene, such as ethylene, in the presence of a Ziegler catalyst, as they are rich in saturated long-chain linear hydrocarbons and accompanied with few branches. It is further preferred to use hydrocarbon waxes synthesized without polymerization because of their structure and molecular weight distribution suitable for easy fractionation.
  • the wax shows a peak in a molecular weight region of 400 - 2400, further 450 - 2000, particularly 500 - 1600.
  • the resultant toner is provided with preferable thermal characteristics.
  • the release agent may preferably be used in an amount of 0.1 - 20 wt. parts, particularly 0.5 - 10 wt. parts, per 100 wt. parts of the binder resin.
  • the release agent may be uniformly dispersed in the binder resin by a method of mixing the release agent in a solution of the resin at an elevated temperature under stirring or melt-kneading the binder resin together with the release agent.
  • a flowability-improving agent may be optionally blended with the toner to improve the flowability of the toner.
  • Examples thereof may include: powder of fluorine-containing resin, such as polyvinylidene fluoride fine powder and polytetrafluoroethylene fine powder; titanium oxide fine powder, hydrophobic titanium oxide fine powder; fine powdery silica such as wet-process silica and dry-process silica, and treated silica obtained by surface-treating such fine powdery silica with silane coupling agent, titanium coupling agent, silicone oil, etc.
  • a preferred class of the flowability-improving agent includes dry process silica or fumed silica obtained by vapor-phase oxidation of a silicon halide.
  • silica powder can be produced according to the method utilizing pyrolytic oxidation of gaseous silicon tetrachloride in oxygen-hydrogen flame, and the basic reaction scheme may be represented as follows: SiCl4 + 2H2 + O2 ⁇ SiO2 + 4HCl.
  • fine silica powder having an average primary particle size of 0.001 - 2 ⁇ m, particularly 0.002 - 0.2 ⁇ m.
  • Fine silica powder formed by vapor phase oxidation of a silicon halide to be used in the present invention include those sold under the trade names as shown below.
  • AEROSIL Natural Aerosil Co. 130 200 300 380 TT 600 MOX 170 MOX 80 COK 84 Cab-O-Sil (Cabot Co.) M-5 MS-7 MS-75 HS-5 EH-5 Wacker HDK (WACKER-CHEMIE GMBH) N 20 V 15 N 20E T 30 T 40 D-C Fine Silica (Dow Corning Co.) Fransol (Fransil Co.)
  • treated silica fine powder obtained by subjecting the silica fine powder formed by vapor-phase oxidation of a silicon halide to a hydrophobicity-imparting treatment. It is particularly preferred to use treated silica fine powder having a hydrophobicity of 30 - 80 as measured by the methanol titration test.
  • Silica fine powder may be imparted with a hydrophobicity by chemically treating the powder with an organosilicone compound, etc., reactive with or physically adsorbed by the silica fine powder.
  • Example of such an organosilicone compound may include: hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylcholrosilane, bromomethyldimethylchlorosilane, ⁇ -chloroethyltrichlorosilane, ⁇ -chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptans such as trimethylsilylmercaptan, triorganosilyl acrylates, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxan
  • the flowability-improving agent used in the present invention may have a specific surface area of at least 30 m2/g, preferably 50 m2/g, as measured by the BET method according to nitrogen adsorption.
  • the flowability-improving agent may be used in an amount of 0.01 - 8 wt. parts, preferably 0.1 - 4 wt. parts, per 100 wt. parts of the toner.
  • the toner according to the present invention is used for constituting a two-component type developer
  • the toner is blended with a carrier.
  • the carrier used in the present invention may include: surface-oxidized or -unoxidized powder of metals, such as iron, nickel, copper, zinc, cobalt, manganese, chromium and rare earth metals, particles of alloys of these metal, oxide particles, and ferrite particles.
  • a coated carrier obtained by coating the above carrier particles with a resin may preferably be used particularly in a developing method wherein a developing bias is supplied with an AC bias voltage.
  • the coating may be performed according to known methods inclusive of a method applying a coating liquid obtained by dissolving or suspending a coating material such as a resin into a solvent onto the surface of carrier core particles, and a method of powder blending carrier core particles and a coating material.
  • Examples of the coating material firmly applied onto the core particles may include: polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, styrene resin, acrylic resin, polyamide, polyvinyl butyral, aminoacrylate resin, basic dyes and lakes thereof, silica fine powder and alumina fine powder. These coating materials may be used singly or in combination of plural species.
  • the coating material may be applied onto the core particles in a proportion of 0.1 - 30 wt. %, preferably 0.5 - 20 wt. %, based on the carrier core particles.
  • the carrier may preferably have an average particle size of 10 - 100 ⁇ m, more preferably 20 - 70 ⁇ m.
  • a particularly preferred type of carrier may comprise particles of a magnetic ferrite such as Cu-Zn-Fe ternary ferrite surface-coated with a fluorine-containing resin or a styrene-based resin.
  • Preferred coating materials may include mixtures of a fluorine containing resin and a styrene copolymer, such as a mixture of polyvinylidene fluoride and styrene-methyl methacrylate resin, and a mixture of polytetraluforoethylene and styrene-methyl methacrylate resin.
  • the fluorine-containing resin may also be a copolymer, such as vinylidene fluoride/tetrafluoroethylene (10/90 - 90/10) copolymer.
  • Other examples of the styrene-based resin may include styrene/2-ethylhexyl acrylate (20/80 - 80/20) copolymer and styrene/2-ethylhexyl acrylate/methyl methacrylate (20 - 60/5 - 30/10 - 50) copolymer.
  • the fluorine-containing resin and the styrene-based resin may be blended in a weight ratio of 90:10 - 20:80, preferably 70:30 - 30:70.
  • the coating amount may be 0.01 - 5 wt. %, preferably 0.1 - 1 wt. % of the carrier core.
  • the coated magnetic ferrite carrier may preferably include at least 70 wt. % of particles of 250 mesh-pass and 400 mesh-on, and have an average particle size of 10 - 100 ⁇ m, more preferably 20 - 70 ⁇ m. A sharp particle size distribution is preferred.
  • the characteristic values of a binder resin and a long-chain alkyl compound and the particle size distribution of a toner referred to herein may be measured according to the following methods.
  • Measurement may be performed in the following manner by using a differential scanning calorimeter ("DSC-7", available from Perkin-Elmer Corp.).
  • DSC-7 differential scanning calorimeter
  • the sample is placed on an aluminum pan and subjected to measurement in a temperature range of 30 - 200 o C at a temperature-raising rate of 10 o C/min in a normal temperature - normal humidity environment in parallel with a blank aluminum pan as a reference.
  • the glass transition temperature is determined as a temperature of an intersection between a DSC curve and an intermediate line pressing between the base lines obtained before and after the appearance of the absorption peak.
  • the molecular weight (distribution) of a binder resin may be measured based on a chromatogram obtained by GPC (gel permeation chromatography).
  • a column is stabilized in a heat chamber at 40 o C, tetrahydrofuran (THF) solvent is caused to flow through the column at that temperature at a rate of 1 ml/min., and 50 - 200 ⁇ l of a GPC sample solution adjusted at a concentration of 0.05 - 0.6 wt. % is injected.
  • THF tetrahydrofuran
  • the identification of sample molecular weight and its molecular weight distribution is performed based on a calibration curve obtained by using several monodisperse polystyrene samples and having a logarithmic scale of molecular weight versus count number.
  • the standard polystyrene samples for preparation of a calibration curve may be available from, e.g., Pressure Chemical Co.
  • the detector may be an RI (refractive index) detector.
  • RI reffractive index
  • a preferred example thereof may be a combination of ⁇ -styragel 500, 103, 104 and 105 available from Waters Co.; a combination of Shodex KF-801, 802, 803, 804, 805, 806 and 807 available from Showa Denko K.K.
  • the molecular weight (distribution) of a long-chain alkyl compound may be measured by GPC under the following conditions: Apparatus: "GPC-150C” (available from Waters Co.) Column: “GMH-HT” 30 cm-binary (available from Toso K.K.) Temperature: 135 o C Solvent: o-dichlorobenzene containing 0.1 % of ionol. Flow rate: 1.0 ml/min. Sample: 0.4 ml of a 0.15 %-sample.
  • the molecular weight distribution of a sample is obtained once based on a calibration curve prepared by monodisperse polystyrene standard samples, and recalculated into a distribution corresponding to that of polyethylene using a conversion formula based on the Mark-Houwink viscosity formula.
  • a sample material is accurately weighed and dissolved in a mixture solvent, and water is added thereto.
  • the resultant liquid is titrated with 0.1N-NaOH by potentiometric titration using glass electrodes (according to JIS K1557-1970).
  • a sample is accurately weighed into a 100 ml-volumetric flask, and 5 ml of an acetylating agent is accurately added thereto. Then, the system is heated by dipping into a bath of 100 o C ⁇ 5 o C. After 1 - 2 hours, the flask is taken out of the bath and allowed to cool by standing, and water is added thereto, followed by shaking to decompose acetic anhydride. In order to complete the decomposition, the flask is again heated for move than 10 min. by dipping into the bath. After cooling, the flask wall is sufficiently washed with an organic solvent. The resultant liquid is titrated with a N/2-potassium hydroxide solution in ethyl alcohol by potentiometric titration using glass electrodes (according to JIS K0070-1966).
  • Coulter Multisizer II (available from Coulter Electronics Inc.) is used as an instrument for measurement, to which an interface (available from Nikkaki K.K.) for providing a number-basis distribution, and a volume-basis distribution and a personal computer PC 9801 (available from NEC K.K.) are connected.
  • a 1 %-NaCl aqueous solution as an electrolytic solution is prepared by using a reagent-grade sodium chloride.
  • a surfactant preferably an alkylbenzenesulfonic acid salt
  • 2 to 20 mg of a sample is added thereto.
  • the resultant dispersion of the sample in the electrolytic liquid is subjected to a dispersion treatment for about 1 - 3 minutes by means of an ultrasonic disperser, and then subjected to measurement of particle size distribution in the range of 2 - 40 ⁇ m by using the above-mentioned Coulter Multisizer II with a 100 micron-aperture to obtain a volume-basis distribution and a number-basis distribution.
  • a weight-average particle size (D4) is calculated with a central value of each channel taken as a representative value of the channel.
  • Figure 1 shows an electrophotographic apparatus usable as an example of a copying machine or a printer for practicing the image forming method according to the present invention.
  • the apparatus includes a developing means 1 containing a toner 13 according to the present invention.
  • the toner may be a magnetic toner or a non-magnetic toner.
  • a developing means including a two-component type developer comprising a toner and a carrier.
  • a photosensitive member 3 e.g., an OPC photosensitive drum, an amorphous silicon photosensitive drum or a polysilicon photosensitive drum
  • a charging means 11 e.g., a contact charging means such as a charging roller as shown, a charging brush or a charging blade
  • the charged surface of the photosensitive member 3 is irradiated with light 5 (e.g., laser light or light from a halogen lamp) carrying image data to form an electrostatic image on the photosensitive member.
  • light 5 e.g., laser light or light from a halogen lamp
  • the electrostatic image is developed with a magnetic toner 13 (in this embodiment) on a developing sleeve 6 enclosing a magnetic field generating means 15 (e.g., a magnet) of the developing means 1 also equipped with a toner applicator blade 8 (e.g., an elastic blade or a magnetic blade) for applying the toner 13 onto the developing sleeve 6.
  • the development is performed by either the normal development scheme or the reversal development scheme to form a toner image on the photosensitive member 3.
  • the developing sleeve may be supplied, as desired, with an alternating, a pulse, and/or a DC bias voltage from a bias voltage application means 12.
  • the toner image on the photosensitive member 3 arrives at a transfer station to which also a transfer material is conveyed, the back side (side opposite the photosensitive member 3) of the transfer member P is pressed and charged by a transfer means 4 (e.g., a transfer roller as shown or a transfer belt) to which a voltage is applied from a bias application means 33, to electrostatically transfer the toner image on the photosensitive member 3 onto the transfer material P.
  • a transfer means 4 e.g., a transfer roller as shown or a transfer belt
  • the toner image on the photosensitive member 3 can be transferred onto an intermediate transfer member (not shown, such as an intermediate transfer drum or an intermediate transfer belt) and then to the transfer material P.
  • the toner image on the transfer material P separated from the photosensitive member 3 may be fixed onto the transfer material P by a heat-and-pressure application means 35 (e.g., a fixing means as shown wherein a pressure roller 23 is pressed against a fixed heat-generating member 21 via a heat-resistant sheet 22; or a heat-pressure roller fixing means).
  • a portion, if any, of the toner remaining on the photosensitive member 3 after the transfer step may be removed, as desired, from the surface of the photosensitive member 3 by a cleaning means 7 (e.g., a cleaning blade as shown, a cleaning roller or a cleaning brush).
  • the photosensitive member 3 after the cleaning is again subjected to an image forming cycle as described above starting from the charging step by the charging means 11.
  • the photosensitive member 3 as a member to be charged and also an electrostatic image-bearing member generally comprises a photosensitive layer and an electroconductive substrate and is rotated in the direction of an arrow as indicated.
  • the developing sleeve 6 comprising a non-magnetic cylinder as a toner carrying member is rotated in the same direction as the photosensitive member 3 at the developing station.
  • a multi-polar permanent magnet (magnet roll) 15 as a magnetic field-generating means is fixedly disposed.
  • the magnetic toner 13 contained inside the developing means 1 is applied by the applicator blade 8 onto the surface of the developing sleeve, and the toner particles constituting the toner are triboelectrically charged by friction with the applicator blade 8 and/or the developing sleeve 6.
  • the toner may be uniformly applied by the applicator blade 8 in a layer of e.g., 10 - 300 ⁇ m on the surface of the developing sleeve 6.
  • toner particles are transferred onto the electrostatic image on the photosensitive member due to the electrostatic force of the photosensitive member surface and the action of an AC or pulse bias voltage.
  • reference numeral 3 denotes an electrostatic image-bearing member (photosensitive drum); 11, a charger (charging roller); 2, a process-cartridge; 7, a cleaning means; 5, an exposure means; 15, a developer container; 6, a developer-carrying member (developing sleeve); 15, a magnetic field generating means; 8, a layer thickness-regulating elastic member; 4, a transfer means (transfer roller); 20, a stay; 21, a heating member; 21a, a heater substrate; 21b, a heat-generating member; 21c, a surface protective layer; 21d, a temperature-detecting element; 22, a fixing film; 23, a pressing roller; 24, a coil spring; 25, a film edge-regulating member; 26, an electricity-supplying connector; 27, an electricity interrupting member; 28, an inlet guide; and 29, an outlet guide (separation guide).
  • Figure 5 is a schematic sectional view of a process-cartridge detached from a main body of an image forming apparatus as described above.
  • the process-cartridge at least includes a developing means and an electrostatic image-bearing member which are integrated into a cartridge, so as to be detachably mountable to a main body of an image forming apparatus, such as a copying machine or a laser beam printer.
  • the process-cartridge integrally includes a developing means 1, a drum-shaped electrostatic image bearing member (photosensitive drum) 3, a cleaner including a cleaning blade 7, and a primary charger (charging roller) 11.
  • the developing means 1 includes a toner layer thickness-regulating member 8 and a toner vessel containing a magnetic toner 13. At the time of development, a prescribed bias electric field is applied between the photosensitive drum 3 and the developing sleeve 6 carrying the magnetic toner 13 to effect a development of an electrostatic image formed on the photosensitive drum 3.
  • Resin E was prepared from the above ingredients otherwise in the same manner as in production of Resin B in Resin Production Example 2 above.
  • the above ingredients were pre-mixed by a Henschel mixer and melt-kneaded through a twin screw extruder at 130 o C. After cooling, the melt-kneaded product was coarsely crushed by a cutter mill, pulverized by a jet stream pulverizer, and classified by a pneumatic classifier to obtain a magnetic toner (1) having a weight-average particle size (D4) of 6.6 ⁇ m, content of ⁇ 5 ⁇ m particles: 49.3 % (N, % by number), 9.6 % (V, % by volume).
  • D4 weight-average particle size
  • An OPC photosensitive member 3 was primarily charged at a potential of -600 volts and exposed to form an electrostatic latent image thereon having a light part potential V L of -150 volts.
  • the thus-formed toner image was transferred onto plain paper by applying a positive transfer potential and the plain paper carrying the toner image was applied through the heat fixing apparatus 35 to fix the toner image onto the plain paper.
  • the surface temperature detected by a sensor element 21d of a heating member 21 was set to 130 o C, and a total pressure of 6 kg was applied between the heating member 21 and a pressing roller 23 with a nip of 3 mm between the pressing roller 23 and a fixing film 22.
  • the fixing film 22 comprised a 50 ⁇ m-thick heat-resistant polyimide film coated, on its side contacting the transfer material P, with a low-resistivity release layer comprising polytetrafluoroethylene with an electroconductive substance dispersed therein.
  • Toners having particle size distributions respectively shown in Table 1 were prepared in the same manner as in Example 1 except that prescriptions also shown in Table 1 were used. (In Table 1, values x, y and z are average values.)
  • the localization factors of the metal complex compounds (inclusive of azo-type iron complex compound used in Examples) for the respective toners are shown in Table 2. From these toners, Developers Nos. 2 - 21 and Comparative Developers Nos. 1 - 8 were prepared in the same manner as in Example 1.
  • the image resolution was evaluated as follows.
  • An original image was prepared so as to comprise 12 types of resolution images including different number of thin lines per mm, i.e., 2.8, 3.2, 3.6, 4.0, 4.5, 5.0, 5.6, 6.3, 7.1, 8.0, 9.0 and 10.0 lines/mm, respectively, each type including 5 thin lines spaced regularly so as to have a line width and a spacing which were equal to each other.
  • a copy image was prepared by reproducing the original image under the respective image forming conditions and observed through a magnifying glass, whereby the largest number of lines/mm at which the adjacent lines could be observed clearly separately was taken as a resolution.
  • Image fog (%) was evaluated as a difference between the whiteness of a white background portion of a printed image and the whiteness of an original transfer paper by measurement with "Reflectometer” (available from Tokyo Denshoku K.K.). A fog value exceeding 4 % is practically problematic.
  • a checker pattern shown in Figure 4 was printed out and the dot reproducibility was evaluated by counting the number of lacked dots. The results were evaluated according to the following standards: o (very good): lack of 2 dots or less/100 dots o (good): lack of 3 - 5 dots/100 dots ⁇ (fair): lack of 6 - 10 dots/100 dots x (poor): lack of 11 dots or more/100 dots
  • a sample image having an image percentage of about 5 % was printed out, and the anti-offset characteristic was evaluated by the degree of s soiling on the image after printing of 3000 sheets. The results were evaluated by the following standards.
  • a toner for developing electrostatic images having a uniform composition and uniform performances over varying sizes of toner particles is constituted by (a) a binder resin, (b) a long-chain alkyl compound and (c) an azo-type iron complex.
  • the long-chain alkyl compound is represented by the following formula (1), (2) or (3): wherein x and y independently denote an average value in the range of 35 - 150; z denotes an average value in the range of 1 - 5, and R denotes H or an alkyl group having 1 - 10 carbon atoms.
  • the azo-type iron complex compound is represented by the following formula (4); wherein X1 and X2 independently denote hydrogen atom, lower alkyl group, lower alkoxy group, nitro group or halogen atom; m and m' denote an integer of 1 - 3; R1 and R3 independently denote hydrogen atom, C1 ⁇ 18 alkyl or alkenyl, sufonamide, mesyl, sulfonic acid group, carboxy ester group, hydroxy, C1 ⁇ 18 alkoxy, acetylamino, benzoylamino or halogen atom; n and n' denote an integer of 1 - 3; R2 and R4 denote hydrogen atom or nitro group; and A+ denotes a cation including 75 - 98 mol. % of ammonium ion and another ion selected from the group consisting of hydrogen ion, sodium ion, potassium iron and mixtures thereof.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Developing Agents For Electrophotography (AREA)
  • Electrophotography Configuration And Component (AREA)
EP95107141A 1994-05-13 1995-05-11 Toner zur Entwicklung elektrostatischer Bilder, Bilderzeugungsverfahren und Prozesskartusche Expired - Lifetime EP0686883B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP12330394 1994-05-13
JP123303/94 1994-05-13

Publications (2)

Publication Number Publication Date
EP0686883A1 true EP0686883A1 (de) 1995-12-13
EP0686883B1 EP0686883B1 (de) 1998-07-29

Family

ID=14857208

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95107141A Expired - Lifetime EP0686883B1 (de) 1994-05-13 1995-05-11 Toner zur Entwicklung elektrostatischer Bilder, Bilderzeugungsverfahren und Prozesskartusche

Country Status (8)

Country Link
EP (1) EP0686883B1 (de)
KR (1) KR0173020B1 (de)
CN (1) CN1091889C (de)
AU (1) AU673122B2 (de)
CA (1) CA2149272C (de)
DE (1) DE69503708T2 (de)
ES (1) ES2119269T3 (de)
SG (1) SG34223A1 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6300024B1 (en) 1999-06-30 2001-10-09 Canon Kabushiki Kaisha Toner, two-component type developer, heat fixing method, image forming method and apparatus unit
EP1293835A2 (de) * 2001-05-14 2003-03-19 Heidelberger Druckmaschinen Aktiengesellschaft Elektrophotographischer Toner mit stabilen triboelektrischen Eigenschaften
US6641969B2 (en) * 1999-06-04 2003-11-04 Ricoh Company, Ltd. Magnetic toner with negative polarity for developing latent electrostatic images, and image forming apparatus using the same
EP1426830A1 (de) * 2002-12-06 2004-06-09 Orient Chemical Industries, Ltd. Ladungskontrollmittel sowie Toner zur Entwicklung elektrostatischer Bilder

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0276147A2 (de) * 1987-01-20 1988-07-27 Xerox Corporation Toner und Entwicklerzusammensetzungen mit Wachsen von langkettigen Alcoholen
JPH02151876A (ja) * 1988-12-05 1990-06-11 Canon Inc 磁性トナー及びその現像方法
EP0461672A2 (de) * 1990-06-15 1991-12-18 Canon Kabushiki Kaisha Bilderzeugungsgerät.
EP0592018A2 (de) * 1989-07-28 1994-04-13 Canon Kabushiki Kaisha Bilderzeugungsvorrichtung und Entwickler für die Entwicklung elektrostatischer Bilder
EP0621513A2 (de) * 1993-04-20 1994-10-26 Canon Kabushiki Kaisha Toner zur Entwicklung elektrostatischer Bilde, Bilderzeugungsgerät und Prozesskassette

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61155463A (ja) * 1984-12-28 1986-07-15 Hodogaya Chem Co Ltd 金属錯塩化合物および電子写真用トナ−
JPS6424256A (en) * 1987-07-21 1989-01-26 Ricoh Kk Electrostatic charge image developing toner
US4925765A (en) * 1988-12-23 1990-05-15 E. I. Du Pont De Nemours And Company Negative solid block toner

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0276147A2 (de) * 1987-01-20 1988-07-27 Xerox Corporation Toner und Entwicklerzusammensetzungen mit Wachsen von langkettigen Alcoholen
JPH02151876A (ja) * 1988-12-05 1990-06-11 Canon Inc 磁性トナー及びその現像方法
EP0592018A2 (de) * 1989-07-28 1994-04-13 Canon Kabushiki Kaisha Bilderzeugungsvorrichtung und Entwickler für die Entwicklung elektrostatischer Bilder
EP0461672A2 (de) * 1990-06-15 1991-12-18 Canon Kabushiki Kaisha Bilderzeugungsgerät.
EP0621513A2 (de) * 1993-04-20 1994-10-26 Canon Kabushiki Kaisha Toner zur Entwicklung elektrostatischer Bilde, Bilderzeugungsgerät und Prozesskassette

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 14, no. 400 (P - 1098)<4343> 29 August 1990 (1990-08-29) *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6641969B2 (en) * 1999-06-04 2003-11-04 Ricoh Company, Ltd. Magnetic toner with negative polarity for developing latent electrostatic images, and image forming apparatus using the same
US6300024B1 (en) 1999-06-30 2001-10-09 Canon Kabushiki Kaisha Toner, two-component type developer, heat fixing method, image forming method and apparatus unit
EP1293835A2 (de) * 2001-05-14 2003-03-19 Heidelberger Druckmaschinen Aktiengesellschaft Elektrophotographischer Toner mit stabilen triboelektrischen Eigenschaften
EP1293835A3 (de) * 2001-05-14 2004-01-07 Heidelberger Druckmaschinen Aktiengesellschaft Elektrophotographischer Toner mit stabilen triboelektrischen Eigenschaften
EP1426830A1 (de) * 2002-12-06 2004-06-09 Orient Chemical Industries, Ltd. Ladungskontrollmittel sowie Toner zur Entwicklung elektrostatischer Bilder
US7094513B2 (en) 2002-12-06 2006-08-22 Orient Chemical Industries, Ltd. Charge control agent and toner for electrostatic image development

Also Published As

Publication number Publication date
DE69503708D1 (de) 1998-09-03
ES2119269T3 (es) 1998-10-01
CA2149272C (en) 2000-10-24
KR0173020B1 (ko) 1999-03-30
DE69503708T2 (de) 1999-02-11
CN1113574A (zh) 1995-12-20
AU1790595A (en) 1995-12-07
CN1091889C (zh) 2002-10-02
SG34223A1 (en) 1996-12-06
EP0686883B1 (de) 1998-07-29
AU673122B2 (en) 1996-10-24
KR950033707A (ko) 1995-12-26
CA2149272A1 (en) 1995-11-14

Similar Documents

Publication Publication Date Title
EP0621513B1 (de) Toner zur Entwicklung elektrostatischer Bilde, Bilderzeugungsgerät und Prozesskassette
EP0898204B1 (de) Toner und Bildherstellungsverfahren
EP1291726B1 (de) Toner und Wärmefixierungsverfahren
EP1336903B1 (de) Bilderzeugungsverfahren mit zumindest zwei Geschwindigkeitsmoden
US5707771A (en) Toner for developing electrostatic image
EP1172703B1 (de) Toner und Vielfarben-Bilderzeugungsverfahren
US6569589B2 (en) Toner, toner production process and image forming method
US5955234A (en) Toner for developing electrostatic image, and image forming method
EP0961175B1 (de) Toner mit negativer triboelektrischer Aufladbarkeit und Bildherstellungsverfahren
EP0606873A1 (de) Toner zur Entwicklung elektrostatischer Bilder, Ein-/und Zwei-komponenten-Entwickler
US5578408A (en) Toner for developing electrostatic image
EP0827038B1 (de) Toner für die Entwicklung elektrostatischer Bilder und Bilderzeugungsverfahren
US6090515A (en) Toner for developing electrostatic image, image forming method and process cartridge
US6623901B1 (en) Toner for developing electrostatic image
EP1176473B1 (de) Toner, Bildaufzeichungsverfahren und Prozesskartusche
EP0686883B1 (de) Toner zur Entwicklung elektrostatischer Bilder, Bilderzeugungsverfahren und Prozesskartusche
JP3210244B2 (ja) 静電荷像現像用トナー、画像形成方法及びプロセスカートリッジ
JP3230044B2 (ja) 静電荷像現像用トナー，画像形成方法及びプロセスカートリッジ
JP2693082B2 (ja) 静電荷像現像用トナー、画像形成装置、装置ユニット及びファクシミリ装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19950511

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): CH DE ES FR GB IT LI NL

17Q First examination report despatched

Effective date: 19960216

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): CH DE ES FR GB IT LI NL

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: CH

Ref legal event code: NV

Representative=s name: BOVARD AG PATENTANWAELTE

REF Corresponds to:

Ref document number: 69503708

Country of ref document: DE

Date of ref document: 19980903

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2119269

Country of ref document: ES

Kind code of ref document: T3

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 20070516

Year of fee payment: 13

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20070524

Year of fee payment: 13

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080531

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080531

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20080512

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080512

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20130513

Year of fee payment: 19

Ref country code: IT

Payment date: 20130507

Year of fee payment: 19

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20140523

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20140531

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20140528

Year of fee payment: 20

REG Reference to a national code

Ref country code: NL

Ref legal event code: V1

Effective date: 20141201

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20141201

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20140511

REG Reference to a national code

Ref country code: DE

Ref legal event code: R071

Ref document number: 69503708

Country of ref document: DE

REG Reference to a national code

Ref country code: DE

Ref legal event code: R071

Ref document number: 69503708

Country of ref document: DE

REG Reference to a national code

Ref country code: GB

Ref legal event code: PE20

Expiry date: 20150510

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20150510