JP2004287073A - Developer and development method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably obtain good image quality in a trickle developing system over a prolonged period of time. <P>SOLUTION: A carrier for initial use included in the two-component developer at an initial stage of development contains a metal oxide on the surface of a carrier core material and has a volume resistivity of 10<SP>7</SP>-10<SP>12</SP>Ω cm. A developer for replenishment includes 0.05 to 0.44 part by weight of a carrier for replenishment on the basis of 1 part by weight of toner, wherein the carrier for replenishment has a volume resistivity of 10<SP>10</SP>-10<SP>15</SP>Ω cm and higher capability to impart charges to the toner than the carrier for early use. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００８３】
〔評価方法〕
得られた静電潜像現像用現像剤を用いて、上記現像装置を搭載したＦｕｊｉ Ｘｅｒｏｘ社製Ｄｏｃｕ Ｃｏｌｏｒ１２５０により、常温・常湿（２２℃、５５％ＲＨ）、高温・高湿（３０℃、８５％ＲＨ）、低温・低湿（１０℃、２０％ＲＨ）の各環境下で１０００００枚のコピーテストを行い、１０枚後及び１０００００枚後のコピー紙上のかぶり、白点及びキャリアの体積電気抵抗率の変化について評価を行った。
【００８４】
〔初期の現像性の評価〕
各々の現像剤を所定の温度湿度下で一晩放置し、２ｃｍ×５ｃｍのパッチを２個所有する画像をコピーし、ルーペあるいは顕微鏡を用い、１ｃｍ^２当たりのトナー量を数え、かぶりが無い場合は○、１個から５個までを△、それより多い場合を×としてコピー紙上のかぶりについて評価した。白点については目標枚数に達する前に発生した場合を×、未発生の場合を○とし評価した。また、抵抗変化値を測定するため、所定の枚数をコピーした後現像機から現像剤を採取し評価した。初期の評価結果を下記表２に示す。
【００８５】
〔１０万枚後の現像性の評価〕
各々の現像剤を所定の温度湿度下で１０００００枚コピーを採取し、更に一晩放置した後、２ｃｍ×５ｃｍのパッチを２個所有する画像をコピーし、ルーペあるいは顕微鏡を用い、１ｃｍ^２当たりのトナー量を数え、かぶりが無い場合は○、１個から５個までを△、それより多い場合を×としてコピー紙上のかぶりについて評価した。白点については目標枚数に達する前に発生した場合を×、未発生の場合を○とし評価した。また、抵抗変化値を測定するため、所定の枚数をコピーした後現像機から現像剤を採取し、トナーとキャリアを分離したのちキャリアの体積電気抵抗を測定した。初期と比較して変化量が１０^１〜１０^２Ω・ｃｍを○、１０^３〜１０^４Ω・ｃｍであれば△、１０^５Ω・ｃｍ以上の場合を×とし評価した。１０００００枚コピー後の評価結果を下記表３に示す。
【表２】

【表３】

【００８６】
【発明の効果】
上記説明から明らかなように、本発明によれば、いわゆるトリクル現像方式において、常温・常湿はもとより、高温・高湿、低温・低湿の環境下において、長期に渡って安定的に良好な画質を得ることができる。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る現像方法で用いられる現像装置の全体構成を示す概略断面図である。
【図２】体積電気抵抗値の測定方法を示す図である。
【符号の説明】
１ 現像装置本体、２ 現像剤補給装置、３ 現像剤回収装置、４ 現像剤収容槽、５ ハウジング、６ 感光体、７ 現像ロール、８ オーガー、９ 層厚規制部材、１０ マグネットロール、１１ スリーブ、２０ 現像剤カートリッジ、２１ 供給用部材、３０ 回収容器、３１ 回収パイプ。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a replenishing developer used in a so-called trickle developing system and a developing method using the replenishing developer.
[0002]
[Prior art]
Conventionally, when a latent image of a latent image holding material is developed using a two-component developer containing a toner and an initially used carrier, which is stored in advance in a developer storage portion of a developing device, the two-component developer is supplied. A so-called trickle development system is known in which the developer is supplied while developing the developer while collecting the excess developer that becomes excessive in the developer storage section due to the supply of the developer for supply. As the replenishing carrier contained in the replenishing developer, the charge amount is higher than the charge amount of the initially used carrier, and the electric resistance is equal to or lower than the electric resistance of the initially used carrier. What was set was used.
[0003]
For example, JP-A-11-223960 discloses a trickle system in which a replenishing carrier has the same volume electric resistance as a carrier in an initial developing machine.
[0004]
Japanese Patent Application Laid-Open No. H11-202630 discloses that the volume electric resistance of a replenishing carrier is equal to or lower than the volume electric resistance of an initial storage carrier.
[0005]
[Patent Document 1]
JP-A-11-223960
[Patent Document 2]
JP-A-11-202630
[0006]
[Problems to be solved by the invention]
In the conventional trickle developing method, a carrier having a volume electric resistance equal to or lower than the volume electric resistance of the carrier in the initial developing machine is used as a replenishing carrier. For this reason, the replenishment of the replenishing carrier lowers the resistance of the entire carrier in the developing device, causing a charge leak, which may cause poor image quality such as white spots.
[0007]
Then, an object of the present invention is to provide a developer and a developing method which can solve the above-mentioned problems. More specifically, an object of the present invention is to provide a developer and a developing method capable of stably obtaining good image quality over a long period in a so-called trickle developing system.
[0008]
[Means for Solving the Problems]
That is, one embodiment of the present invention provides a method for developing a latent image of a latent image holding material using a two-component developer containing a toner and a carrier, which is contained in a developer containing portion of a developing device. A developer for use in a developing method of replenishing a developer for replenishment with a developer and performing development while collecting excess developer that becomes excessive in the developer accommodating portion due to replenishment of the replenishment developer, The initially used carrier contained in the initial two-component developer contains a metal oxide on the surface of the carrier core material and has a volume electric resistance of 10%. ⁷ -10 ¹² Ω · cm, wherein the replenishing developer contains 0.05 to 0.43 parts by weight of a replenishing carrier with respect to 1 part by weight of the toner. Is 10 ¹⁰ -10 ^Fifteen Ω · cm, and the charge application ability to the toner is higher than that of the initially used carrier.
[0009]
Initial use carrier volume electric resistance is 10 ⁷ If it is less than Ω · cm, the charge exchange property is improved, but the charge amount is reduced, so that a leak occurs and causes fogging. Also, the volume electric resistance of the initially used carrier is 10 ¹² If it is larger than Ω · cm, sufficient charge exchange property cannot be obtained, and rapid charging rise cannot be obtained.
[0010]
According to this, by allowing a certain amount of metal oxide to be present on the surface of the carrier, the fluctuation range of the toner charge amount can be reduced, and good image quality can be obtained over a long period of time.
[0011]
Replenishment carrier volume electric resistance is 10 ¹⁰ If it is less than Ω · cm, the decrease in carrier resistance cannot be sufficiently compensated, and toner impact cannot be prevented. Further, the volume electric resistance of the replenishing carrier is 10 ^Fifteen If it is larger than Ω · cm, the charge exchange property is deteriorated, so that the charge distribution is widened and fogging occurs.
[0012]
The charging ability of the replenishment carrier to the toner is set to be higher than that of the initially used carrier. Specifically, the replenishing carrier has a charge amount of 1.2 to 2 times, more preferably 1.5 times the charged amount of the initially used carrier. The saturation charge of the replenishment carrier obtained by being frictionally charged by stirring with the toner for a certain time is 1.2 to 2 times the saturation charge of the initially used carrier. , More preferably 1.5 to 2 times. If the saturation charge of the replenishment carrier exceeds twice the saturation charge of the initially used carrier, a problem in image quality may occur.
[0013]
If the amount of the replenishment carrier is less than 0.05 part by weight with respect to 1 part by weight of the toner, the volume electric resistance and the charge amount cannot be maintained within appropriate ranges. Further, if the supply carrier is more than 0.43 parts by weight with respect to 1 part by weight of the toner, the amount of the trickle carrier is increased, so that the amount of discharged carriers is increased, the recovery amount is increased, and the cost is increased.
[0014]
As the metal oxide, titanium oxide is desirable.
[0015]
In another aspect of the replenishing developer of the present invention, the replenishing carrier is the same as the carrier core material used in the initially used carrier.
[0016]
Another embodiment of the present invention provides a method for developing a latent image on a latent image holding material using a two-component developer containing a toner and a carrier, which is contained in a developer containing portion of a developing device. A developing method for replenishing the developer with a replenishing developer and performing development while collecting excess developer that becomes excessive in the developer accommodating portion due to replenishment of the replenishing developer, wherein The initially used carrier contained in the component developer contains a metal oxide on the surface of the carrier core material and has a volume electric resistance of 10%. ⁷ -10 ¹² Ω · cm, wherein the replenishing developer contains 0.05 to 0.43 parts by weight of a replenishing carrier with respect to 1 part by weight of the toner. Is 10 ¹⁰ -10 ^Fifteen Ω · cm, and the charge application ability to the toner is higher than that of the initially used carrier.
[0017]
In another aspect of the developing method of the present invention, the replenishment carrier is the same as the carrier core material used in the initially used carrier.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described through embodiments of the present invention.
[0019]
FIG. 1 is a schematic cross-sectional view showing the entire configuration of a developing device used in a developing method according to one embodiment of the present invention. This developing device is used, for example, in an electrophotographic copying machine, and is roughly divided into a developing device main body 1, a developer replenishing device 2, and a developer collecting device 3.
[0020]
The developing device main body 1 includes a housing 5 having a developer accommodating tank 4 for accommodating a starting two-component developer G0 including a toner and a carrier, and a photoconductor as a latent image carrier at an opening side of the housing 5. A developing roller 7 as a developer carrying and conveying member arranged to rotate in a state close to the developing roller 6; and a developer stirring and conveying member as a developer stirring and conveying member arranged to rotate in the developer accommodating tank 4. The main part is constituted by the auger 8 and the layer thickness regulating member 9 disposed in a state of being pressed against or in close proximity to the surface of the developing roll 7.
[0021]
The developing roll 7 is a cylindrical sleeve 11 that is rotatably driven and has a magnet roll 10 fixed inside. Further, the developer storage tank 4 is formed of storage spaces 4b and 4c which are divided into two by a partition wall 4a at the center side and are communicated by communication portions at both ends, and are rotated by an auger 8 rotating in each of the storage spaces 4b and 4c. The developer G0 is circulated and transported between the storage spaces 4b and 4c while being stirred. The layer thickness regulating member 9 has a double structure of a non-magnetic member and a magnetic member, and is disposed so that the tip thereof faces a predetermined magnetic pole of the magnet roll 10.
[0022]
The developer replenishing device 2 includes a developer cartridge 20 that stores a two-component developer G1 for replenishment, and a supply member that sends out and supplies the two-component developer G1 in the developer cartridge 20 to the developer storage tank 4. 21. The supply member 21 is provided in the vicinity of a supply port 5 a opened at a predetermined location of the housing 5, and is driven in accordance with a detection signal from a toner density sensor (not shown) provided in the developer storage tank 4 to supply an appropriate amount. The developer G1 is supplied.
[0023]
The developer collection device 3 includes a collection container 30 that collects the excess two-component developer G2 in the developer storage tank 4 and a collection container 30 that collects the excess developer G2 that overflows from the developer storage tank 4. And a recovery pipe 31 to be sent to The collection pipe 31 is disposed so that its upper opening 31a is located at a predetermined height in the developer storage tank 4, and collects the developer that exceeds the upper opening 31a at the predetermined height. It has become.
[0024]
A non-magnetic toner is used as the toner T0 of the start two-component developer G0 previously stored in the developer storage tank 4, and the carrier (hereinafter referred to as “initial use carrier”) C0 is ferrite or the like. A magnetic carrier in which a resin coating layer made of a predetermined charge control material is formed on a core material of the above, wherein a carrier containing a metal oxide such as titanium oxide on the surface of the carrier is used.
[0025]
On the other hand, as the toner T1 of the two-component developer G1 for replenishment stored in the developer cartridge 20, the same toner T0 previously stored in the developer storage tank 4 is used. A magnetic carrier having a resin coating layer formed of a predetermined charge control material formed on a core material such as ferrite is used as C1.
[0026]
The volume electric resistance of the initially used carrier is 10 ⁷ -10 ¹² Ω · cm, and the volume electric resistance of the replenishment carrier is 10 ¹⁰ -10 ^Fifteen Ω · cm. The replenishment carrier has a higher charging ability to the toner than the initially used carrier.
[0027]
Further, the two-component developer G1 contains a replenishing carrier at a mixing ratio of 0.05 to 0.44 parts by weight with respect to 1 part by weight of the toner.
[0028]
By setting the initial carrier and the replenishing carrier in the above ranges and combinations, the fluctuation range of the toner charge amount can be reduced.
[0029]
(Development method)
In the developing method according to one embodiment of the present invention, development is performed in the following procedure.
[0030]
First, the two-component developer G0 previously stored in the developer storage tank 4 is stirred by the auger 8 and sufficiently mixed and triboelectrically charged. Attaches in layers to the surface. The layered developer G00 adhered to the developing roll 7 is regulated to a predetermined thickness by the layer thickness regulating member 9 to form a uniform layer. It is transported to the area D. Then, in the developing area D, the two-component developer toner is electrostatically attracted to the latent image formed on the photoreceptor 7 in accordance with the image of the original on the copying machine main body side (not shown), and development is performed. A toner image is formed on the body 7. The toner image on the photoreceptor 7 is transferred and fixed on recording paper on the copying machine main body side, whereby a document is copied.
[0031]
By repeating this developing operation, the toner contained in the developer G0 in the developer storage tank 4 is consumed and gradually decreases. When the toner reduction is detected by the toner concentration sensor, the developer is discharged. The supply member 21 of the replenishing device 2 is driven, whereby the two-component developer G1 stored in the developer cartridge 20 is replenished. The replenished new two-component developer G1 is stirred by the auger 8 in the developer accommodating tank 4, and is sufficiently mixed with the two-component developer G0 stored before replenishment.
[0032]
Since the carrier is replenished together with the toner at a predetermined ratio by the replenishment of the two-component developer G1, the amount of the developer in the developer accommodating tank 4 gradually becomes excessive. The excess two-component developer G2 overflows beyond the regulation height of the storage unit 4 and is stored in the recovery container 30 through the recovery pipe 31 of the recovery device 3.
[0033]
Next, specific examples of the toner and the carrier used in the developing method will be described.
[0034]
〔toner〕
The toner is mainly composed of a binder resin and a colorant. Examples of the binder resin include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl acetate, methyl acrylate and acrylic. Α-methylene aliphatic monocarboxylic acid esters such as ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, vinyl ethyl ether, Known homopolymers or copolymers such as vinyl ethers such as vinyl methyl ether and vinyl butyl ether, and vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone can be exemplified. Representative binder resins include polyethylene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, and styrene-maleic anhydride copolymer. Examples thereof include a coalescence, polyethylene and polypropylene, and a styrene-butyl acrylate copolymer is preferable. Furthermore, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin, and wax can be mentioned. These toner particles may optionally contain known additives such as a charge control agent and a fixing aid. Preferred fixing aids include paraffin wax having a melting point of 70 to 100C.
[0035]
Examples of the coloring agent include carbon black, nigrosine, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 12, C.I. I. Pigment Blue 15: 1, C.I. I. And known colorants such as CI Pigment Blue 15: 3. In addition to the above components, the toner of the present invention may contain known charge control agents and cleaning aids as necessary. If necessary, known external additives such as inorganic oxides and organic fine particles can be added.
[0036]
The shape of the toner is preferably in the range of shape factor SF1 = 100 to 140, and more preferably a shape close to a true sphere with shape factor SF1 = 100 to 120.
[0037]
Here, the shape factor SF1 is obtained by taking an optical microscope image of a spherical core scattered on a slide glass into a Luzex image analyzer via a video camera, and obtaining a maximum length (ML) and a projected area (A) for 100 or more spherical cores. ) Is measured, and the average value of the calculation results of the equation (1) is determined to be the shape factor SF1.
Shape factor = (ML2 / A) × (π / 4) × 100 Equation (1)
[0038]
[Carrier]
The carrier used in the present invention is a so-called coat carrier in which magnetic particles such as ferrite, magnetite, and iron powder are coated with a coating material. The volume average particle diameter of the magnetic particles is preferably in the range of 10 to 55 μm. When the volume average particle size exceeds 55 μm, the coating layer is peeled off due to the stress in the developing machine, and the carrier resistance is reduced. Conversely, when the thickness is smaller than 10 μm, toner impact occurs and carrier resistance increases. It is presumed that these phenomena are caused by the weight per carrier particle. The magnetic force of the magnetic particles should have a saturation magnetic value at 3000 Oe of 50 emu / g or more, and more preferably 60 emu / g or more. If the saturation magnetic value is less than 50 emu / g, the carrier is developed on the photoreceptor together with the toner.
[0039]
As the coating material for coating the magnetic particles, a charge-imparting resin for imparting chargeability to the toner and a low surface energy material for preventing the transfer of the toner component to the carrier are used. Conductive powder for resistance control can be used. Examples of the charge-imparting resin for imparting a negative charge to the toner include amino resins, for example, urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Known resins such as a polyvinylidene resin, an acrylic resin, a polymethyl methacrylate resin, a polyacrylonitrile resin, a polyvinyl acetate resin, a polyvinyl acetate resin, a polyvinyl alcohol resin, a polyvinyl butyral resin, and a cellulose resin such as an ethyl cellulose resin are exemplified. Examples of the charge-imparting resin for imparting a positive charge to the toner include polystyrene resins such as polystyrene resins and styrene-acryl copolymer resins, styrene methacrylate copolymer resins, halogenated olefin resins such as polyvinyl chloride, and polyethylene terephthalate resins. And known resins such as polyester resins such as polybutylene terephthalate resin and polycarbonate resins.
[0040]
Examples of the low surface energy material for preventing the transfer of the toner component to the carrier include a polystyrene resin, a polyethylene resin, a polyvinyl fluoride resin, a polyvinylidene fluoride resin, a polytrifluoroethylene resin, a polyhexafluoropropylene resin, and a fluorine-containing resin. Copolymers of vinylidene fluoride and acrylic monomers, copolymers of vinylidene fluoride and vinyl fluoride, fluoroterpolymers such as terpolymers of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomers, And known resins such as silicone resins. Known conductive powders such as metal powder, carbon black, titanium oxide, tin oxide, and zinc oxide can be used as the conductive powder. These conductive powders preferably have an average particle size of 1 μm or less. When the particle diameter is larger than 1 μm, it becomes difficult to control the electric resistance. In addition, a conductive resin or the like can be used as needed.
[0041]
The solvent used for the coating layer forming raw material solution is not particularly limited as long as it dissolves the coating resin, and for example, toluene, aromatic hydrocarbons such as xylene, acetone, ketones such as methyl ethyl ketone, Ethers such as tetrahydrofuran and dioxane can be used. Further, the average film thickness of the resin coating layer and the average thickness calculated from the average particle diameter of the core particles is usually 0.1 to 10 μm, but in the present invention, in order to express a stable volume electric resistance of the carrier over the diameter, It is preferably from 0.5 to 3.0 μm.
[0042]
The initially used carrier has a metal oxide on the surface. As the metal oxide, titanium oxide is desirable, but is not limited thereto, and aluminum oxide or the like can also be used.
[0043]
Next, examples of the present invention and comparative examples will be described, but the present invention is not limited to these examples. In the following description, “parts” means “parts by weight”. In the production of the toner, carrier and developer used in the examples and comparative examples, each measurement was performed by the following methods.
[0044]
[Measurement of volume electric resistance]
As shown in FIG. 2, the measurement sample 53 (thickness H) is sandwiched between the lower electrode 54 and the upper electrode 52, and the thickness is measured with the dial gauge 51 while applying pressure from above. It was measured with a high voltage resistance meter 55. Specifically, a carrier sample was filled in a lower electrode 54 of 100Φ, an upper electrode 52 was set, a load of 3.43 kg was applied from above, and the thickness was measured with a dial gauge. Next, a voltage was applied, and a current value was read to obtain a volume electric resistance value.
[0045]
[Measurement of surface titanium content]
The amount of titanium on the carrier surface was measured using an X-ray photoelectron spectrometer (JPS9000-MX) manufactured by JASCO. The surface atomic concentration was estimated from the measured peak intensity of each element. The relative atomic factors provided by JASCO were used to calculate the surface atomic concentration.
[0046]
(Preparation of toner)
[Production of Toner A]
Styrene-n-butyl acrylate resin (Tg = 58 ° C., Mn = 4000, Mw = 24000) 100 parts
Carbon black (Mogal L; manufactured by Cabot Corporation) ... 3 parts
The mixture was kneaded with an extruder, pulverized with a jet mill, and then dispersed with an air classifier to produce black toner particles having a volume average particle diameter D50 = 8.0 μm. Silica (trade name: R972, manufactured by Nippon Aerosil Co., Ltd.) was added to the obtained black toner particles with a 0.4% by weight Henschel mixer to obtain black toner particles (toner A). The shape factor (SF1) of the obtained toner A was 140.
[0047]
[Production of Toner B]
[Preparation of resin dispersion 1]
Styrene ... 370 parts
n-butyl acrylate 30 parts
Acrylic acid: 4 parts
Dodecanethiol: 24 copies
Carbon tetrabromide 4 parts
The above components are mixed and dissolved, and 6 parts of a nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) and an anionic surfactant (Neogen SC: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 10 parts dissolved in 550 parts of ion-exchanged water were emulsified and dispersed in a flask, and while slowly mixing for 10 minutes, a solution in which 4 parts of ammonium persulfate was dissolved in 50 parts of ion-exchanged water was added. After purging with nitrogen, while stirring the inside of the flask, the content was heated in an oil bath until the content reached 70 ° C., and emulsion polymerization was continued for 5 hours. As a result, a resin dispersion 1 in which resin particles having an average particle diameter of 160 nm, Tg = 59 ° C., and a weight average molecular weight Mw = 12000 were dispersed was obtained.
[0048]
[Adjustment of resin dispersion 2]
Styrene ... 280 parts
n-butyl acrylate 120 parts
Acrylic acid 8 parts
The above components are mixed and dissolved, and 6 parts of a nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) and an anionic surfactant (Neogen SC: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 12 parts were dissolved in 550 parts of ion-exchanged water and emulsified and dispersed in a flask. While slowly mixing for 10 minutes, a solution in which 3 parts of ammonium persulfate was dissolved in 50 parts of ion-exchanged water was added. After purging with nitrogen, while stirring the inside of the flask, the content was heated in an oil bath until the content reached 70 ° C., and emulsion polymerization was continued for 5 hours. As a result, a resin dispersion liquid 2 in which resin particles having an average particle diameter of 110 nm, Tg = 52 ° C., and a weight average molecular weight Mw = 550,000 were dispersed was obtained.
[0049]
[Preparation of Colorant Dispersion 1]
Carbon black (Mogal L: manufactured by Cabot) 50 parts
Nonionic surfactant (Nonypol 400: manufactured by Sanyo Chemical Co., Ltd.) 5 parts
Ion-exchanged water: 200 parts
The above components are mixed and dissolved, and dispersed using a homogenizer (Ultra Turrax T50: manufactured by IKA) for 10 minutes, and a colorant dispersion liquid 1 in which colorant (carbon black) particles having an average particle diameter of 250 nm are dispersed. Was prepared.
[0050]
(Release agent dispersion)
Paraffin wax (HNP0190: Nippon Seiro Co., Ltd., melting point 85 ° C) 50 parts
Cationic surfactant (Sanisol B50: manufactured by Kao Corporation) ... 5 parts
Ion-exchanged water: 200 parts
The above components were mixed, heated to 95 ° C., dispersed in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA) for 10 minutes, and then dispersed using a pressure discharge type homogenizer. A release agent dispersion in which release agent particles having an average particle diameter of 550 nm were dispersed was prepared.
[0051]
[Preparation of Toner B]
Resin dispersion 1 120 parts
80 parts of resin dispersion 2
Colorant dispersion: 200 parts
Release agent dispersion liquid 40 parts
1.23 parts of polyaluminum chloride
The resin fine particle dispersion, the colorant particle dispersion, and the release agent particle dispersion were each adjusted, and while mixing and stirring a predetermined amount thereof, polyaluminum chloride was added to neutralize ionically, and each of the above particles was neutralized. Aggregates were formed. After adjusting the pH of the system to 4.0 with an inorganic hydroxide, the mixture was heated to 95 ° C. and fused and coalesced for 6 hours. Thereafter, through sufficient washing, solid-liquid separation and drying steps, black toner particles (toner B) were obtained. The volume average particle diameter of this toner was D50 = 6.0 μm, and the shape factor (SF1) was 115.
[0052]
(Preparation of carrier)
[Preparation of carrier A]
Ferrite particles (average particle size = 50 µm) ... 100 parts
Toluene 14 parts by weight
Styrene-methyl methacrylate copolymer (component ratio 90:10, Mw: 90,000) 2 parts
Carbon black (Regal 330: manufactured by Cabot Corporation) ... 0.2 part
The above components excluding the ferrite particles were stirred / dispersed with a stirrer for 60 minutes to prepare a coating layer forming raw material solution. Next, the raw material solution and ferrite particles were placed in a vacuum degassing type kneader, stirred at 60 ° C. for 30 minutes, degassed under reduced pressure while further heating, and dried to obtain Carrier A.
[0053]
When the amount of titanium on the carrier surface was measured by the above-described measuring method, the amount of titanium on the surface of the obtained carrier A was 0.01%, and the volume electric resistance was 10%. ^Thirteen Ω · cm.
[0054]
[Preparation of carrier B]
Ferrite particles (average particle size = 50 µm) ... 100 parts
Toluene 14 parts
Styrene-methyl methacrylate copolymer (component ratio: 90:10 Mw: 90,000) 2 parts
Carbon black (Regal 330: manufactured by Cabot) 0.1 part
The above components excluding the ferrite particles were stirred / dispersed with a stirrer for 60 minutes to prepare a coating layer forming raw material solution. Next, the raw material solution and the ferrite particles were placed in a vacuum deaeration type kneader, stirred at 60 ° C. for 30 minutes, degassed under reduced pressure while further heating, and dried to obtain a carrier B.
[0055]
When the amount of titanium on the surface of the carrier was measured by the above measurement method, the amount of titanium on the surface of the obtained carrier B was 0.01%, and the volume electric resistance was 10%. ¹⁴ Ω · cm.
[0056]
[Preparation of carrier C]
Ferrite particles (average particle size = 50 µm) ... 100 parts
Toluene 14 parts
Styrene-methyl methacrylate copolymer (component ratio: 90:10 Mw: 90,000) 2 parts
Carbon black (Regal 330: manufactured by Cabot) 0.5 part
The above components excluding the ferrite particles were stirred / dispersed with a stirrer for 60 minutes to prepare a coating layer forming raw material solution. Next, the raw material solution and the ferrite particles were placed in a vacuum deaeration type kneader, stirred at 60 ° C. for 30 minutes, deaerated by depressurizing while further heating, and dried to prepare a carrier C.
[0057]
When the amount of titanium on the surface of the carrier was measured by the above measurement method, the amount of titanium on the surface of the obtained carrier C was 0.01%, and the volume electric resistance was 10%. ⁹ Ω · cm.
[0058]
[Preparation of carrier D]
Ferrite particles (average particle size = 50 µm) ... 100 parts
Toluene 14 parts
Styrene-methyl methacrylate copolymer (component ratio: 90:10 Mw: 90,000) 2 parts
Carbon black (Regal 330: manufactured by Cabot Corporation) 0.01 part
The above components excluding the ferrite particles were stirred / dispersed with a stirrer for 60 minutes to prepare a coating layer forming raw material solution. Next, the raw material solution and the ferrite particles were placed in a vacuum deaeration type kneader, stirred at 60 ° C. for 30 minutes, deaerated by depressurizing while further heating, and dried to prepare a carrier D.
[0059]
When the amount of titanium on the surface of the carrier was measured by the above measurement method, the amount of titanium on the surface of the obtained carrier D was 0.01%, and the volume electric resistance was 10%. ¹⁶ Ω · cm.
[0060]
[Preparation of carrier E]
Carrier A (the above product) 100 parts
Titanium oxide (Untreated KA20 coupling agent, manufactured by Titanium Industries) 0.3 part
The carrier A and titanium oxide were placed in a V-type blender (volume: 5 L), stirred at 40 rpm for 20 minutes, and then passed through a sieve having openings of 75 μm to prepare a carrier E.
[0061]
When the amount of titanium on the surface of the carrier was measured by the above-described measuring method, the amount of titanium on the surface of the obtained carrier E was 2.5%, and the volume electric resistance was 10%. ⁸ Ω · cm
[0062]
[Preparation of carrier F]
Carrier B (the above product) 100 parts
Titanium oxide (Untreated KA20 coupling agent, manufactured by Titanium Industries) 0.3 part
The carrier B and titanium oxide were placed in a V-type blender (volume: 5 L), stirred at 40 rpm for 20 minutes, and then passed through a sieve having openings of 75 μm to prepare a carrier F.
[0063]
When the amount of titanium on the surface of the carrier was measured by the above measurement method, the amount of titanium on the surface of the obtained carrier F was 2.5%, and the volume electric resistance was 10%. ¹⁰ Ω · cm.
[0064]
[Preparation of carrier G]
Carrier C (the above product) 100 parts
Titanium oxide (Untreated KA20 coupling agent, manufactured by Titanium Industries) 0.3 part
The carrier C and the titanium oxide were placed in a V-type blender (volume: 5 L), stirred at 40 rpm for 20 minutes, and then passed through a sieve having openings of 75 μm to prepare a carrier G.
[0065]
When the amount of titanium on the surface of the carrier was measured by the above measurement method, the amount of titanium on the surface of the obtained carrier G was 2.5%, and the volume electric resistance was 10%. ⁶ Ω · cm.
[0066]
[Preparation of carrier H]
Carrier D (the above product) 100 parts
Titanium oxide (Untreated KA20 coupling agent, manufactured by Titanium Industries) 0.3 part
A carrier H was prepared by putting the carrier D and titanium oxide in a V-type blender (volume: 5 L), stirring the mixture at 40 rpm for 20 minutes, and passing it through a sieve having openings of 75 μm.
[0067]
When the amount of titanium on the surface of the carrier was measured by the above-described measuring method, the amount of titanium on the surface of the obtained carrier H was 2.5%, and the volume electric resistance was 10%. ¹¹ Ω · cm.
[0068]
(Adjustment of initial developer)
[Adjustment of Initial Developer A]
Carrier E (1 part) and toner A (0.08 part) were mixed with a V-type blender for 20 minutes to obtain an initial developer A.
[0069]
[Adjustment of Initial Developer B]
The carrier F (1 part) and the toner A (0.08 part) were mixed with a V-type blender for 20 minutes to obtain an initial developer B.
[0070]
[Adjustment of Initial Developer C]
The carrier G (1 part) and the toner A (0.08 part) were mixed with a V-type blender for 20 minutes to obtain an initial developer C.
[0071]
[Adjustment of Initial Developer D]
Carrier H (1 part) and toner A (0.08 part) were mixed with a V-type blender for 20 minutes to obtain an initial developer D.
[0072]
[Adjustment of Initial Developer E]
The carrier A (1 part) and the toner A (0.08 part) were mixed with a V-type blender for 20 minutes to obtain an initial developer E.
[0073]
[Adjustment of Initial Developer F]
The carrier E (1 part) and the toner B (0.08 part) were mixed with a V-type blender for 20 minutes to obtain an initial developer F.
[0074]
[Adjustment of Initial Developer G]
The carrier F (1 part) and the toner B (0.08 part) were mixed with a V-type blender for 20 minutes to obtain an initial developer G.
[0075]
(Adjustment of replenishment developer)
[Adjustment of replenishment developer A]
Carrier A (1 part) and toner A (6 parts) were mixed with a V-type blender for 20 minutes to obtain replenishment developer A.
[0076]
[Adjustment of replenishment developer B]
Carrier B (1 part) and toner A (6 parts) were mixed with a V-type blender for 20 minutes to obtain a replenishing developer B.
[0077]
[Adjustment of replenishment developer C]
Carrier C (1 part) and toner A (6 parts) were mixed with a V-type blender for 20 minutes to obtain a replenishing developer C.
[0078]
[Adjustment of replenishment developer D]
Carrier D (1 part) and toner A (6 parts) were mixed with a V-type blender for 20 minutes to obtain developer D for replenishment.
[0079]
[Adjustment of replenishment developer E]
The carrier A (1 part) and the toner A (20 parts) were mixed with a V-type blender for 20 minutes to obtain a replenishing developer E.
[0080]
[Adjustment of replenishment developer F]
Carrier A (1 part) and toner B (6 parts) were mixed with a V-type blender for 20 minutes to obtain a replenishing developer F.
[0081]
[Adjustment of replenishment developer G]
Carrier B (1 part) and toner B (6 parts) were mixed with a V-type blender for 20 minutes to obtain a replenishing developer G.
[0082]
Table 1 below shows combinations of the initial developer and the replenishing developer.
[Table 1]

[0083]
〔Evaluation method〕
Using the obtained developer for developing an electrostatic latent image, Docu Color 1250 manufactured by Fuji Xerox equipped with the above-mentioned developing device was used at room temperature and normal humidity (22 ° C., 55% RH), and high temperature and high humidity (30 ° C., 85% RH), 100,000 copy tests in each environment of low temperature and low humidity (10 ° C, 20% RH), fog, white spot and volume resistivity of carrier on copy paper after 10 and 100,000 copies. The change in rate was evaluated.
[0084]
[Evaluation of initial developability]
Each developer was allowed to stand at a predetermined temperature and humidity overnight, and an image having two patches of 2 cm × 5 cm was copied, and a 1 cm image was obtained using a loupe or a microscope. ² The fogging on the copy paper was evaluated by counting the amount of toner per unit. When there was no fog, the evaluation was as follows: ○: 1 to 5: Δ; Regarding white spots, evaluation was made as x when it occurred before reaching the target number, and as ○ when it did not occur. Further, in order to measure the resistance change value, after a predetermined number of copies were made, the developer was sampled from the developing machine and evaluated. Table 2 below shows the initial evaluation results.
[0085]
[Evaluation of developability after 100,000 sheets]
After collecting 100,000 copies of each developer under a predetermined temperature and humidity, and further leaving it overnight, copy an image having two 2 cm × 5 cm patches, and use a loupe or a microscope to copy 1 cm. ² The fogging on the copy paper was evaluated by counting the amount of toner per unit. When there was no fog, the evaluation was as follows: ○: 1 to 5: Δ; Regarding white spots, evaluation was made as x when it occurred before reaching the target number, and as ○ when it did not occur. Further, in order to measure the resistance change value, a predetermined number of sheets were copied, the developer was collected from the developing machine, the toner and the carrier were separated, and then the volume electric resistance of the carrier was measured. 10 change compared to the initial ¹ -10 ² Ω · cm = 10 ³ -10 ⁴ Ω · cm, 10 ⁵ The case of Ω · cm or more was evaluated as x. Table 3 shows the evaluation results after 100,000 copies.
[Table 2]

[Table 3]

[0086]
【The invention's effect】
As is apparent from the above description, according to the present invention, in a so-called trickle developing method, not only at normal temperature and normal humidity, but also at high temperature and high humidity, and at low temperature and low humidity, stable image quality can be stably obtained over a long period of time. Can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view illustrating an overall configuration of a developing device used in a developing method according to an embodiment of the present invention.
FIG. 2 is a diagram showing a method of measuring a volume electric resistance value.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Development device main body, 2 Developer supply device, 3 Developer collection device, 4 Developer accommodation tank, 5 Housing, 6 Photoconductor, 7 Development roll, 8 Auger, 9 Layer thickness regulating member, 10 Magnet roll, 11 Sleeve, Reference Signs List 20 developer cartridge, 21 supply member, 30 collection container, 31 collection pipe.

Claims (2)

When developing the latent image of the latent image holding material using the two-component developer containing toner and carrier stored in the developer storage portion of the developing device, a replenishing developer is supplied to the two-component developer. And a developer used in a developing method of performing development while collecting excess developer that becomes excessive in the developer accommodating portion due to replenishment of the replenishing developer,
The initially used carrier contained in the two-component developer at the early stage of development contains a metal oxide on the surface of the carrier core material, and has a volume electric resistance of 10 ⁷ to 10 ¹² Ω · cm,
The replenishing developer contains a replenishing carrier in an amount of 0.05 to 0.43 parts by weight with respect to 1 part by weight of the toner.
The developer, wherein the replenishing carrier has a volume electric resistance of 10 ¹⁰ to 10 ¹⁵ Ω · cm, and has a higher charging ability to the toner than the initially used carrier. When developing the latent image of the latent image holding material using the two-component developer containing toner and carrier stored in the developer storage portion of the developing device, a replenishing developer is supplied to the two-component developer. And a developing method for performing development while collecting excess developer that becomes excessive in the developer storage unit due to replenishment of the replenishing developer,
The initially used carrier contained in the two-component developer at the early stage of development contains a metal oxide on the surface of the carrier core material, and has a volume electric resistance of 10 ⁷ to 10 ¹² Ω · cm,
The replenishing developer contains a replenishing carrier in an amount of 0.05 to 0.43 parts by weight with respect to 1 part by weight of the toner.
The replenishing carrier has a volume electric resistance of 10 ¹⁰ to 10 ¹⁵ Ω · cm, and has a higher charging ability to the toner than the initially used carrier.

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