JP2009251151A - Toner for developing electrostatic charge image, and image forming method using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner for developing an electrostatic charge image, quick in a rise for charging, capable of obtaining instantaneously a charge quantity required for development, having enhanced flowability, not generating deposition or the like onto a developing roller, and capable of maintaining thereby charging performance over a long period, and an image forming device using the same. <P>SOLUTION: This toner for developing the electrostatic charge image contains at least a binding resin, a coloring agent and external additive agent, the binding resin contains a polyester having an urea bond or an urethane bond, and at least one of the additives is laminar double hydroxide containing Mg element and Al element. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrostatic image developing toner and an image forming method using the same.

  Image forming methods based on electrostatic latent image development methods such as electrophotography can form high-quality images at high speed and can be applied to color image formation. Therefore, currently, copiers for offices, printers for output from computers, Or it is widely used as a light printing machine.

  The performance required for image forming apparatuses in these fields is that high-quality images can be formed at a higher speed, and that image formation can be performed stably over a long period of time.

  In particular, the one-component development method does not use a carrier, so the developing device can be miniaturized, and it is not necessary to control the mixing ratio between the electrostatic image developing toner (hereinafter also simply referred to as toner) and the carrier. The structure and control of the developing device can be simplified. Therefore, it is particularly suitable for a color image forming apparatus that needs to use a plurality of small machines, printers, or developing devices.

  However, there is a demand for a performance that allows the toner to be instantaneously raised to a predetermined charge amount by contacting the toner with a charging member or a developing roller without using a carrier. As a countermeasure, he insisted that by adding large particle external additives such as various metal oxides, he played a role of pseudo carrier, secured an appropriate amount of charge, suppressed fogging and secured image density. There are also examples (see, for example, Patent Document 1).

However, it is a fact that large particle external additives such as metal oxides cause problems such as a decrease in fluidity and adhesion contamination to the developing roller, and are not a complete solution.
JP-A-9-127783

  The present invention has been made to solve the above problems.

  That is, according to the present invention, the charge rise is fast, the charge amount necessary for development can be obtained instantaneously, and the fluidity is high, and adhesion to the developing roller does not occur. An electrostatic charge image developing toner that can be maintained, and an image forming method using the same.

  As a result of intensive studies, the inventors of the present invention have found that the object of the present invention can be achieved by adopting the following configuration.

(1)
A toner containing at least a binder resin, a colorant and an external additive, wherein the binder resin contains a polyester having a urea bond or a urethane bond, and at least one of the external additives is Mg A toner for developing an electrostatic charge image, which is a layered double hydroxide containing an element and an Al element.

(2)
The toner for developing an electrostatic charge image according to (1), wherein the layered double hydroxide is in the following range.

Element ratio: 1.0 ≦ Mg (atm%) / Al (atm%) ≦ 5.0
(3)
The electrostatic charge according to (1) or (2), wherein the addition amount of the layered double hydroxide is 0.02 to 1.0% by mass with respect to all toner components other than the external additive. Toner for image development.

(4)
(1) An image forming method, wherein the toner for developing an electrostatic charge image according to any one of (1) to (3) is used, and nonmagnetic one-component development is performed.

  According to the present invention, the charge rise is fast, the charge amount necessary for development can be obtained instantaneously, and the fluidity is high and adhesion to the developing roller does not occur, so the charging performance is maintained over a long period of time. It is possible to provide an electrostatic charge image developing toner that can be used, and an image forming method using the same.

  Next, the present invention will be described in more detail.

  The present invention is characterized by using “a layered double hydroxide containing Mg element and Al element” as means for controlling the electrostatic characteristics of the toner. The reason why only the layered double hydroxide has a remarkable effect in the present invention is not clear.

  The reason why the layered double hydroxide particles are effective in the present invention is presumed to be that the positive chargeability is strong and the resistance value is quite high, which effectively acts on the chargeability control. That is, a part of Mg atoms in the hydroxide layer of magnesium, which is a divalent metal, is replaced with trivalent Al atoms, so that positive chargeability is developed. In order to compensate for the negative charge, a layered compound layer in which anionic ions are incorporated will be formed, but the effect of the present invention is also considered to be due to the structure.

  In short, the “layered double hydroxide containing Mg element and Al element” according to the present invention preferably has the following structure.

Element ratio: 1.0 ≦ Mg (atm%) Al (atm%) ≦ 5.0
The toner of the present invention preferably contains 0.02 to 1.0% by mass of the layered double hydroxide with respect to all toner components other than the external additive. If the amount is less than 2.0% by mass, the effect of the invention may not be sufficiently obtained. If the amount is more than 100% by mass, the charging performance may be lowered.

  The toner of the present invention is suitable for use with a negative charge, because the layered double hydroxide is easy to work as a positively chargeable microcarrier and the toner negative chargeability can be obtained more stably. Will.

  Furthermore, the present invention can be used as a non-magnetic one-component toner or a magnetic one-component toner containing a magnetic substance in the toner. However, in the non-magnetic one-component development method, it is necessary to apply a sufficient amount of charge only by bringing the toner into contact with the charging member or the surface of the developing roll. Thus, the effect of the present invention is more remarkably exhibited.

[Composition of toner resin]
The polyester resin used in the present invention is called urethane-modified polyester or urea-modified polyester, and is modified so as to have a urethane bond or a urea bond in the molecular structure.

  Examples of the monomer for producing the polyester resin include the following.

(Polyhydric alcohol component)
Specific examples of the polyhydric alcohol component include polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2-bis (4 -Hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -polyoxyethylene (2,0) -2,2- Diols such as bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene Glycol, polyethylene glycol, propylene glycol, dipropylene glycol, isopentylglycol Hydrogenated bisphenol A, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, xylylene glycol, 1,4-cyclohexanedimethanol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, bis -(Β-hydroxyethyl) terephthalate, tris- (β-hydroxyethyl) isocyanurate, 2,2,4-trimethylolpentane-1,3-diol, etc., are used alone or in combination of two or more. Used. Furthermore, as a hydroxycarboxylic acid component, for example, p-oxybenzoic acid, vanillic acid, dimethylolpropionic acid, malic acid, tartaric acid, 5-hydroxyisophthalic acid and the like can be added.

(Polyvalent carboxylic acid component)
Specific examples of the polyvalent carboxylic acid component include malonic acid, succinic acid, glutaric acid, dimer acid, phthalic acid, isophthalic acid, terephthalic acid, isophthalic acid dimethyl ester, terephthalic acid dimethyl ester, terephthalic acid monomethyl ester, tetrahydro Terephthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, dimethyltetrahydrophthalic acid, endomethylenehexahydrophthalic acid, fumaric acid, naphthalenetetracarboxylic acid, diphenolic acid, trimellitic acid, pyromellitic acid, trimesic acid, cyclopentane Dicarboxylic acid, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 2,2-bis- (4-carboxyphenyl) propane, trimellitic anhydride And 4,4-diaminofe Diimidecarboxylic acid obtained from rumethane, tris- (β-carboxyethyl) isocyanurate, isocyanurate ring-containing polyimide carboxylic acid, tolylene diisocyanate, xylylene diisocyanate or isophorone diisocyanate trimerization product and trimellitic anhydride Isocyanate ring-containing polyimide carboxylic acid, and acid anhydrides, acid chlorides, and lower alkyl (C1 to C3) esters of these, and the like are used alone or in combination of two or more.

(Polyisocyanate compound)
Specific examples of the polyvalent isocyanate compound for introducing an isocyanate group include, for example, aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and 2,6-diisocyanatomethylcaproate, isophorone diisocyanate, and cyclohexylmethane diisocyanate. And cycloaliphatic polyisocyanates such as cycloaliphatic polyisocyanate, tolylene diisocyanate, aromatic diisocyanate such as diphenylmethane diisocyanate, and araliphatic diisocyanate such as α, α, α ′, α′-tetramethylxylylene diisocyanate. Of these, alicyclic polyisocyanates are preferred. These are preferably used alone or in combination.

(Urethane-modified polyester resin)
Hereinafter, first, the urethane-modified polyester will be described.

  Examples of the polyester modified with a urethane bond include a reaction product of a polyester prepolymer (A) having an isocyanate group and a polyol (B). Examples of the polyester prepolymer (A) having an isocyanate group include those obtained by polycondensation of a polyvalent carboxylic acid and a polyhydric alcohol, and a polyester having an active hydrogen group further reacted with a polyisocyanate. It is done.

  Examples of the active hydrogen group possessed by the polyester include hydroxyl groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), amino groups, carboxyl groups, mercapto groups, and the like. Among these, alcoholic hydroxyl groups are preferred.

  Polyisocyanates include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic diisocyanates ( Tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; the polyisocyanates blocked with phenol derivatives, oximes, caprolactam, etc. And combinations of two or more of these.

  The ratio of the polyisocyanate is 5/1 to 1 as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group from the viewpoint of low-temperature fixability and hot offset resistance. / 1, preferably 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1.

  The content of the polyisocyanate component in the prepolymer (A) having an isocyanate group at the terminal is usually 0.5 to 40% by mass, preferably 1 to 30% by mass, and more preferably 2 to 20% by mass. The number of isocyanate groups contained per molecule in the prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2.5 on average. It is.

  Examples of the polyol (B) include polypropylene glycol, polytetramethylene glycol, adipate type polyol, polycaprolactone type polyol, acrylic polyol, polybutadiene polyol, 1.4-butanediol, monoethylene glycol, and silicone polyol.

  The urethane-modified polyester used in the present invention is produced by a one-shot method or a prepolymer method. The weight average molecular weight of the urethane-modified polyester is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000 from the viewpoint of hot offset resistance.

  The number average molecular weight of the urethane-modified polyester may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. In the case of urethane-modified polyester alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, more preferably 2000 to 8000, from the viewpoint of low-temperature fixability and glossiness of toner images. Urethane-modified polyester is suitable for the present invention because it has a function of improving the particle strength of the toner and has high solubility in a solvent.

(Urea-modified polyester resin)
Next, the urea-modified polyester resin is obtained by chain-extending a polyester prepolymer with at least a urea bond.

  Such a urea-modified polyester resin can be synthesized, for example, by the method shown below.

First, a polyester prepolymer is synthesized, and then an isocyanate group is introduced by reacting the prepolymer with a polyvalent isocyanate compound to obtain an isocyanate group-containing prepolymer. For example, when the terminal group of the polyester prepolymer is a hydroxyl group, a urethane bond is formed by reaction with a polyvalent isocyanate compound, and an isocyanate group-containing prepolymer having an isocyanate group introduced by the urethane bond is obtained. Further, for example, when the terminal group of the polyester prepolymer is a carboxyl group, an isocyanate group-containing prepolymer in which an amide bond is formed by the generation of CO ₂ by reaction with a polyvalent isocyanate compound, and the isocyanate group is introduced by the amide bond. can get.

  Next, chain extension is performed by reacting the isocyanate group-containing prepolymer with a polyvalent amino compound to obtain a urea-modified polyester resin. A urea bond is formed by the reaction of the isocyanate group-containing prepolymer and the polyvalent amino compound, and a urea-modified polyester resin in which the isocyanate group-containing prepolymer is chain-extended by the urea bond via the polyvalent amino compound is obtained.

  The polyester prepolymer constituting the urea-modified polyester resin is obtained by subjecting a polyhydric alcohol component and a polyvalent carboxylic acid component to a polycondensation reaction by heating in a reduced pressure atmosphere, in the presence of a catalyst and / or in a nitrogen atmosphere as necessary. Synthesized.

  Specific examples of the polyvalent amino compound for chain extension include, for example, diamine, aromatic diamine such as phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diamino-3,3. Examples include alicyclic diamines such as dimethyldicyclohexylmethane, diaminecyclohexane, and isophoronediamine, and aliphatic diamines such as ethylenediamine, tetramethylenediamine, and hexamethylenediamine. Examples of the trivalent or higher polyamine include diethylenetriamine and triethylenetetramine. Of these, alicyclic diamines are preferred. These are preferably used alone or in combination.

  The softening point of the urea-modified polyester resin is usually 80 to 130 ° C, particularly preferably 95 to 120 ° C, regardless of whether the resin is contained in the core particle or the shell layer.

  The content of the urea-modified polyester resin is not particularly limited as long as the effect of the present invention is obtained. When contained in the shell layer, 2 to 40% by mass, particularly 4 to 30% by mass is preferable with respect to the total amount of the shell layer constituting resin, and when contained in the core particle, 2 to 40% with respect to the total amount of the core particle constituting resin. % By mass, particularly 4 to 30% by mass is preferred.

(External additive)
At least one of the external additives is a layered double hydroxide containing Mg element and Al element. It is preferable that the element ratio (Mg (atm%) / Al (atm%)) of Mg element and Al element of the layered ascites hydroxide particles is 1.0 to 5.0.

When an example of the layered ascites hydroxide particles is represented by a general formula,
Mg _1-x · Al _x · (OH) ₂ · (CO ₃ ) _{x / 2} · H ₂ O _m
(In the formula, X is preferably 0.1 to 0.5, and m represents an integer.)
The reason why the layered double hydroxide used in the external additive of the present invention is preferable is not clear, but it seems that the charging characteristics greatly influence it. At this time, the addition amount is preferably 0.02% by mass or more and 1.0% by mass or less with respect to 100 parts by mass of the toner particles in order to adjust the charging characteristics and the aggregation degree of the toner.

  The contents of Mg element and Al element in the oxide particles can be measured by a fluorescent X-ray analyzer.

  An X-ray fluorescence analyzer (XRF) irradiates a sample with continuous X-rays to generate characteristic X-rays (fluorescent X-rays) unique to the elements constituting the sample. Then, the generated fluorescent X-ray is spectrally separated (spectral dispersion type) by a spectral crystal to generate a spectrum, the obtained spectrum is measured, and the constituent elements are quantitatively analyzed from the intensity.

  In the fluorescent X-ray analysis method, a calibration curve is prepared with a fluorescent X-ray analyzer using oxide particles with known contents of magnesium atoms and aluminum atoms, and using the calibration curve, The content of magnesium atoms and aluminum atoms is obtained. Examples of the fluorescent X-ray analyzer include XRF-1800 (manufactured by Shimadzu Corporation) and ZSX-100E (manufactured by Rigaku Corporation).

Quantification of magnesium atoms and aluminum atoms by a fluorescent X-ray analyzer can be performed, for example, by the following procedure.
(1) First, a sample for preparing a calibration curve is prepared. A known amount of magnesium oxide is added to 100 parts by mass of styrene powder to produce a measurement pellet for magnesium oxide. Similarly, a known amount of aluminum oxide is added to 100 parts by mass of styrene powder to produce a measurement pellet for aluminum oxide.
(2) Each of the produced pellets is measured with a fluorescent X-ray analyzer, and a calibration curve is prepared from the peak intensity obtained from each sample for magnesium or aluminum in styrene powder.
(3) Next, the oxide particles containing magnesium atoms and aluminum atoms used in the present invention are measured with a fluorescent X-ray analyzer, and the obtained peak intensity is collated with a calibration curve. Quantify the content of aluminum atoms.

  In the fluorescent X-ray analysis, rhodium (Rh) Kα ray is used as the X-ray, and, for example, quantification is performed under an output condition of a tube voltage of 20 kV and a tube current of 100 mA. As the spectral crystal, known spectral crystals for magnesium atoms and titanium atoms can be used.

  Furthermore, a known scintillation counter or a proportion counter can be used as a detector for detecting the spectrum.

  Of course, as the external additive, besides this, a finer external additive can be used than usual. As the fine particle external additive, generally used particles such as silica and titanium oxide having a number average primary particle size of about 5 to 30 nm can be used.

[Development method]
As a toner production method, a so-called pulverization method in which a colorant and, if necessary, a charge control agent or a release agent are added to a toner resin, melt kneaded, cooled and pulverized to prepare a toner, or a toner resin And a toner component such as a coloring agent can be dissolved and dispersed in a solvent, then dispersed in a dispersion medium, granulated, and dried.

[Development method]
In the present invention, the developing method is not particularly limited, and any developing method such as a non-magnetic / magnetic one-component developing method or a two-component developing method using a carrier can be used.

  However, as described above, the effect of the present invention works most effectively in non-magnetic one-component development.

(Image forming method)
Next, an image forming apparatus that forms an image using the toner according to the present invention will be described.

  FIG. 1 is a schematic sectional view showing an example of a full-color image forming apparatus.

  In the full-color image forming apparatus shown in FIG. 1, a charging brush 111 that uniformly charges the surface of the photosensitive drum 10 to a predetermined potential around the photosensitive drum 10 that is rotationally driven, and the photosensitive drum 10 A cleaner 112 for scraping off the remaining toner is provided.

  Further, a laser scanning optical system 20 for scanning and exposing the photosensitive drum 10 charged by the charging brush 111 with a laser beam is provided. The laser scanning optical system 20 includes a laser diode, a polygon mirror, and an fθ optical element. As is well known, print data for each of yellow, magenta, cyan, and black is transferred from the host computer to the control unit. The laser scanning optical system 20 sequentially outputs the laser beam as a laser beam based on the print data for each color, scans and exposes the photosensitive drum 10, and thereby the static image for each color is formed on the photosensitive drum 10. Electro latent images are sequentially formed.

  In addition, the full-color developing cartridge 30 that performs full-color development by supplying toner of each color to the photosensitive drum 10 on which the electrostatic latent image is formed in this manner is provided with yellow, magenta, cyan, and black around the support shaft 33. Four color-developing cartridges 31Y, 31M, 31C, and 31Bk containing each non-magnetic one-component toner are provided. The developing cartridges 31Y, 31M, 31C, and 31Bk rotate around the support shaft 33, and It is guided to a position facing the photosensitive drum 10.

  Further, in each of the developing cartridges 31Y, 31M, 31C, and 31Bk in the full-color developing cartridge 30, as shown in FIG. 5, the toner is formed on the outer peripheral surface of the developer carrier (developing roller) 25 that rotates and conveys the toner. A regulating member is pressed (contacted), and the toner regulating member regulates the amount of toner conveyed by the developing roller 25 and charges the conveyed toner. In the full color developing cartridge 30, two toner regulating members may be provided in order to appropriately regulate and charge the toner conveyed by the developing roller.

  As described above, each time an electrostatic latent image of each color is formed on the photosensitive drum 10 by the laser scanning optical system 20, the full-color developing cartridge 30 is rotated about the support shaft 33 as described above. The developing cartridges 31Y, 31M, 31C, and 31Bk containing the corresponding color toners are sequentially guided to positions facing the photosensitive drum 10, and the developing rollers 25 in the developing cartridges 31Y, 31M, 31C, and 31Bk are moved. The charged toner of each color is sequentially supplied onto the photosensitive drum 10 in which the electrostatic latent images of each color are sequentially formed as described above in contact with or without contact with the photosensitive drum 10. Development is to be performed.

  Further, an endless intermediate transfer belt 40 that is rotationally driven is provided as an intermediate transfer body 40 at a position downstream of the full-color developing cartridge 30 in the rotation direction of the photosensitive drum 10. Is driven to rotate in synchronization with the photosensitive drum 10. The intermediate transfer belt 40 is pressed by a rotatable primary transfer roller 41 so as to come into contact with the photosensitive drum 10, and a portion of a support roller 42 that supports the intermediate transfer belt 40 includes: A secondary transfer roller 43 is rotatably provided, and the recording material S such as recording paper is pressed against the intermediate transfer belt 40 by the secondary transfer roller 43.

  Further, a cleaner 50 that scrapes off toner remaining on the intermediate transfer belt 40 is provided in a space between the full-color developing cartridge 30 and the intermediate transfer belt 40 so as to be able to contact and separate from the intermediate transfer belt 40. ing.

  Further, the paper feeding means 60 that guides the recording material S such as plain paper to the intermediate transfer belt 40 includes a paper feeding tray 61 that accommodates the recording material S and the recording material S that is accommodated in the paper feeding tray 61 one by one. The recording material S fed in synchronization with the paper feed roller 62 for feeding paper and the image formed on the intermediate transfer belt 40 is sent between the intermediate transfer belt 40 and the secondary transfer roller 43. The recording material S sent between the intermediate transfer belt 40 and the secondary transfer roller 43 in this way is pressed against the intermediate transfer belt 40 by the secondary transfer roller 43. The toner image is pressed and transferred from the intermediate transfer belt 40 to the recording material S.

  On the other hand, the recording material S on which the toner image is pressed and transferred as described above is guided to the fixing device 70 by the conveying means 66 constituted by an air suction belt or the like, and is transferred by the fixing device 70. The toner image is fixed on the recording material S, and then the recording material S is discharged onto the upper surface of the apparatus main body 100 through the vertical conveyance path 80.

  Next, the operation of forming a full color image using this full color image forming apparatus will be specifically described.

  First, the photosensitive drum 10 and the intermediate transfer belt 40 are rotationally driven in the respective directions at the same peripheral speed, and the photosensitive drum 10 is charged to a predetermined potential by the charging brush 11.

  The photosensitive drum 10 thus charged is exposed to a yellow image by the laser scanning optical system 20 to form an electrostatic latent image of the yellow image on the photosensitive drum 10. The yellow image is developed by supplying the yellow toner charged by the toner regulating member as described above from the developing cartridge 31Y in which the yellow toner is accommodated in the photosensitive drum 10, and the yellow toner image is thus formed. The intermediate transfer belt 40 is pressed against the body drum 10 by the primary transfer roller 41, and the yellow toner image formed on the photosensitive drum 10 is primarily transferred to the intermediate transfer belt 40.

  After the yellow toner image is transferred to the intermediate transfer belt 40 in this way, the full-color developing cartridge 30 is rotated around the support shaft 33 as described above, and the developing cartridge 31M containing magenta toner is exposed to light. As in the case of the yellow image described above, the magenta image is exposed to the photosensitive drum 10 charged by the laser scanning optical system 20 to form an electrostatic latent image. The electrostatic latent image is developed by the developing cartridge 31M containing magenta toner, and the developed magenta toner image is primarily transferred from the photosensitive drum 10 to the intermediate transfer belt 40. The black image is exposed, developed, and primary transferred in sequence, and yellow, magenta, cyan, and black are printed on the intermediate transfer belt 40. Superimposed in sequence to form a toner image of full color toner image.

  When the final black toner image is primarily transferred onto the intermediate transfer belt 40, the recording material S is fed between the secondary transfer roller 43 and the intermediate transfer belt 40 by the timing roller 63, and the secondary transfer roller. The recording material S is pressed against the intermediate transfer belt 40 by 43, and the full color toner image formed on the intermediate transfer belt 40 is secondarily transferred onto the recording material S.

  When the full-color toner image is secondarily transferred onto the recording material S in this way, the recording material S is guided to the fixing device 70 by the conveying means 66, and the full-color toner transferred by the fixing device 70 is transferred. The image is fixed on the recording material S, and then the recording material S is discharged onto the upper surface of the apparatus main body 1 through the vertical conveyance path 80.

<Development cartridge>
The cartridge of the present invention has at least a developing roller and a regulating blade, and is used as a developing device for non-magnetic one-component toner.

  FIG. 2 is a schematic cross-sectional view showing an example of a developing cartridge of a non-magnetic one-component developer.

  The developing cartridge 20 shown in FIG. 2 has a buffer chamber 26 adjacent to the developing roller 25, and a hopper 27 and the like adjacent to the buffer chamber 26.

  In the buffer chamber 26, a regulating blade 28, which is a toner regulating member, is disposed in a state of being pressed (contacted) with the developing roller 25. The regulating blade 28 regulates the charge amount and adhesion amount (conveyance amount) of the toner on the developing roller 25. Further, an auxiliary blade 29 for assisting in regulating the toner charge amount and the adhesion amount on the developing roller 25 may be further provided on the downstream side of the regulating blade 28 with respect to the rotation direction of the developing roller 25.

  A supply roller 30 is pressed against the developing roller 25. The supply roller 30 is driven to rotate in the same direction as the developing roller 25 (counterclockwise direction in the drawing) by a motor (not shown). The supply roller 30 has a conductive cylindrical base and a foam layer formed of urethane foam or the like on the outer periphery of the base.

  The hopper 27 contains toner T which is a non-magnetic one-component developer. The hopper 27 is provided with a rotating body 31 for stirring the toner T. A film-like conveying blade is attached to the rotating body 31, and the toner T is conveyed by the rotation of the rotating body 31 in the arrow direction. The toner T conveyed by the conveying blades is supplied to the buffer chamber 26 via a passage 32 provided in a partition wall that separates the hopper 27 and the buffer chamber 26. The shape of the conveying blade is bent while the toner T is conveyed in front of the rotation direction of the blade with the rotation of the rotating body 31 and returns to a straight state when the left end of the passage 32 is reached. Thus, the toner T is supplied to the passage 32 by returning the shape of the blade straightly through the curved state.

  The passage 32 is provided with a valve 321 for closing the passage 32. This valve is a film-like member, and one end is fixed to the upper side of the right side of the passage 32 of the partition wall. When the toner T is supplied from the hopper 27 to the passage 28, the valve 32 is pushed rightward by the pressing force from the toner T. Can be opened. As a result, the toner T is supplied into the buffer chamber 26.

  In the developing cartridge 20, the developing roller 25 is rotationally driven in the direction of the arrow during image formation, and the toner in the buffer chamber 26 is supplied onto the developing roller 25 by the rotation of the supply roller 30. The toner T supplied onto the developing roller 25 is charged and thinned by the regulating blade 28 and the auxiliary blade 29, and then transported to a region facing the image carrier, where the electrostatic latent image on the image carrier is transferred. It is used for development. The toner that has not been used for development is neutralized by the neutralizing blade 24 as the developing roller 25 rotates. After reducing the electrostatic adhesive force between the developing roller 25 and the toner, the toner is scraped and collected from the developing roller 25 by the supply roller 30.

  In the present invention, the contact pressure average of the regulating blade contacting the developing roller is 10 to 50 N / m, preferably 15 to 45 N / m.

  By making the contact pressure within the above range, the non-magnetic one-component toner can be transported with a uniform thickness without damaging the resin layer of the developing roller, and a uniform charge amount is imparted to the non-magnetic one-component toner. be able to.

《Regulatory blade》
The regulating blade used in the present invention is installed in the developing cartridge for the purpose of uniformly thinning the toner on the surface of the developing roller and uniformly charging the toner.

  As the regulating blade, phosphor bronze having a spring elasticity capable of uniformly thinning and charging the non-magnetic one-component toner and controlling the average contact pressure to the developing roller within a specified range is used.

  Phosphor bronze can provide a stable charge to the non-magnetic one-component toner as compared with other metal elastic materials (for example, stainless steel).

  This is presumed that since the phosphor bronze charging sequence is more positive than stainless steel, the non-magnetic one-component toner can be charged more stably than stainless steel.

  The material of the phosphor bronze plate is preferably a JIS H3731 equivalent.

  The thickness of phosphor bronze is not particularly limited, but if a thickness of 0.03 to 0.12 mm is used, the contact pressure average can be easily adjusted to the above range.

  The regulating blade is fixed by a holder, and is used by being attached to the developing cartridge while being fixed to the holder.

  Next, the present invention will be further described by showing typical embodiments of the present invention, but of course, the present invention is not limited to these embodiments.

(Production of polyester resin having urea bond (urea modified))
Into a reaction vessel equipped with a stirrer and a nitrogen introduction tube, 724 parts by mass of bisphenol A ethylene oxide 2-mole adduct, 276 parts by mass of isophthalic acid and 2 parts by mass of dibutyltin oxide were placed at 230 ° C. for 8 hours under normal pressure. The mixture was further reacted for 5 hours under a reduced pressure of 12 mmHg (1 mmHg is 133 Pa), cooled to 160 ° C., and then 32 parts by mass of phthalic anhydride was added and reacted for 2 hours. Next, the mixture was cooled to 80 ° C. and reacted with 188 parts by mass of isophorone diisocyanate in ethyl acetate for 2 hours to obtain an isocyanate-modified amorphous polyester. Next, after 267 parts by mass of this isocyanate-modified amorphous polyester and 14 parts by mass of isophoronediamine were reacted at 50 ° C. for 2 hours, ethyl acetate was distilled off to obtain a urea-modified polyester resin [A] as a binder resin. Obtained. The weight average molecular weight (Mw) of this urea-modified polyester resin [A] was 64,000.

(Manufacture of polyester resin having urethane bond (urethane-modified))
Into a reaction vessel equipped with a stirrer and a nitrogen introduction tube, 724 parts by mass of bisphenol A ethylene oxide 2-mole adduct, 276 parts by mass of isophthalic acid and 2 parts by mass of dibutyltin oxide were placed at 230 ° C. for 8 hours under normal pressure. The mixture was further reacted for 5 hours under a reduced pressure of 12 mmHg (1 mmHg is 133 Pa), cooled to 160 ° C., and then 32 parts by mass of phthalic anhydride was added and reacted for 2 hours. Next, the mixture was cooled to 80 ° C. and reacted with 188 parts by mass of isophorone diisocyanate in ethyl acetate for 2 hours to obtain an isocyanate-modified amorphous polyester. Next, after 267 parts by mass of this isocyanate-modified amorphous polyester and 20 parts by mass of polypropylene glycol were reacted at 50 ° C. for 2 hours, ethyl acetate was distilled off to obtain a urethane-modified polyester resin [B] as a binder resin. Obtained. The urethane-modified polyester resin [B] had a weight average molecular weight (Mw) of 68,000.

(Production example of unmodified polyester)
In the production example of the urea-modified polyester resin [A], the polyester resin [C] was obtained without performing the urea-modification treatment with isophoronediamine. The weight average molecular weight (Mw) of the polyester resin [C] was 48,000.

(Toner Production Example 1)
Urea-modified polyester resin [A] 100 parts Carbon black (MA60 manufactured by Mitsubishi Chemical Corporation) 4.5 parts Pigment Blue 15: 3 0.5 part Carnauba wax (acid value 1.5, flakes) 5 parts Charge control agent ( Bontron E-84 manufactured by Orient Chemical Co., Ltd. 2 parts The above materials were mixed with a mixer, and then dissolved and dispersed at 45 ° C. using 200 parts of ethyl acetate and a sand mill to prepare an oil phase serving as a dispersed phase.

Separately
700 parts of ion-exchanged water 1 part of sodium dodecylbenzenesulfonate was stirred and dispersed to prepare an aqueous phase that became a continuous phase. The oil phase was added to the water phase while stirring with a homomixer (made by Tokushu Kika Kogyo Co., Ltd.), and the number of rotations of stirring was adjusted to produce oil droplets having a volume average particle size of about 0.5 μm. Thereafter, the mixture was distilled off under reduced pressure at 50 ° C. to remove ethyl acetate to obtain a black gray emulsion. The dispersion obtained is transferred to a stirring tank equipped with an impeller, and an aqueous solution obtained by dissolving 10 parts of aluminum sulfate in 90 parts of ion-exchanged water is gradually added dropwise with stirring at low speed to form aggregated particles, and then the liquid Stirring was continued at a temperature of 90 ° C., and a part of the aggregation and melting was sampled and confirmed by a scanning electron microscope. Thereafter, washing with water and filtration were repeated, and the resulting cake was dried under reduced pressure to obtain black colored particles. 100 parts of the colored particles obtained and 0.8 part by mass of the layered double hydroxide described in Table 1, spherical monodispersed silica (silica sol obtained by the sol-gel method is treated with hexamethyldisilazane, dried and pulverized. 1.8 parts by mass of silica having a particle size of 137 nm) and 0.3 parts by mass of silica manufactured by the gas phase method and treated with octylmethoxysilane (particle size of 14 nm) were mixed with a Henschel mixer, and the opening was 50 μm. The toner 1 was obtained by removing coarse particles and aggregates by passing through a sieve.

(Toner Production Examples 2 to 13)
Electrophotographic toners 2 to 13 were prepared in the same manner except that the monomer composition was changed as shown in Table 1 in the production of toner 1. Table 1 shows the resin compositions and performances of the toners 1 to 13.

(Evaluation)
As an image evaluation apparatus, a digital color printer “magiccolor 5440DL” (manufactured by Konica Minolta Business Technologies) was used.

  Each toner and each developer produced above are loaded in order, and printing is performed for a total of 200,000 sheets in an environment of 20 ° C./50% RH and 30 ° C./85% RH. The initial state and after printing 200,000 sheets The following evaluation was performed.

(Image density)
The image density of the toner after the initial stage and after the endurance was evaluated by measuring the density of the solid portion of the printed image using a reflection densitometer “RD-918” (manufactured by Macbeth). The image density is 0.80 or higher.

A: Each density of the solid (solid) image portion of Bk is 1.2 or more (good)
○: Each density of the solid (solid) image part of Bk is 0.8 or more (no problem in practical use)
×: Each density of the solid (solid) image portion of Bk is less than 0.8 (fogging)
For the fogging of the printed image of the toner after the initial and endurance, the density of the unprinted printing paper (white paper) is measured at 20 locations, the image density is measured, and the average value is used as the white paper density. Similarly, the image density was measured at 20 places on the white background portion of the printed paper, the average density was calculated, and the value obtained by subtracting the white paper density from the average density was evaluated as the fog density. The measurement was performed using a reflection densitometer “RD-918” (manufactured by Macbeth). In addition, the fog is less than 0.010 as acceptable.

A: Fog density less than 0.005 Good B: Fog density 0.005 or more and less than 0.010 Generally good (no problem in practical use)
×: Fog density 0.010 or higher

  As apparent from Table 1, Examples 1 to 10 in the present invention have good characteristics in both fog density and solid image density, but Comparative Examples 1 to 3 outside the present invention have a problem in at least one of the characteristics. .

1 is a schematic cross-sectional view showing an example of a full-color image forming apparatus. FIG. 3 is a schematic cross-sectional view showing an example of a developing cartridge of a nonmagnetic one-component developing device.

Explanation of symbols

20 developing cartridge 25 developing roller 26 buffer chamber 27 hopper 27
28 Restricting blade 29 Auxiliary blade 30 Supply roller T Toner 31 Rotating body 32 Passage 321 Valve

Claims (4)

A toner containing at least a binder resin, a colorant and an external additive, wherein the binder resin contains a polyester having a urea bond or a urethane bond, and at least one of the external additives is Mg A toner for developing an electrostatic charge image, which is a layered double hydroxide containing an element and an Al element. 2. The electrostatic image developing toner according to claim 1, wherein the layered double hydroxide is within the following range.
Element ratio: 1.0 ≦ Mg (atm%) / Al (atm%) ≦ 5.0 3. The electrostatic charge image development according to claim 1, wherein the addition amount of the layered double hydroxide is 0.02 to 1.0 mass% with respect to all toner components other than the external additive. Toner. A non-magnetic one-component development using the electrostatic charge image developing toner according to claim 1.

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