JPH02284162A - Method for developing by using polyester type color developer - Google Patents

Abstract

PURPOSE:To always stablize triboelectrifiability, almost irrespective of environments, such as temperature and humidity, by forming the nearest distance between the surface of a devel oper carrying sleeve and the surface of an electrostatic latent image bearing drum and regulat ing the maximum intensity of an electric field in an image zone formed by the nearest dis tance. CONSTITUTION:The volume average particle diameter of the polyester type resin particles containing a colorant is regulated to 6 - 11 mum, and when at least one of fluidity donor is triboelectrified with a carrier, the absolute value of the triboelectrification amount is controlled to <= 20 muC/g, and the maximum electric field intensity F (V/mum) of the image forming zone formed by the potential VL (V) of an electrostatic charge image, the same polarity voltage component VDC(V) alternating electric field, the potential VPP Max(V) of the point of applying the maximum electric field which exists at opposite side, and the nearest distance G (mum) between the surface of the developer carrying sleeve and the surface of the electrostatic latent image bearing drum satisfies expressions I and II in which H means water vapor pressure, and 2.5 <= k <= 3.50, 0.15 <= log H <= 1.6, thus permitting the obtained developer to be hardly affected by environments such as temperature and humidity and stabi lized in triboelectrifiability, and sharp images superior in durable stability to be obtained.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a developer used for developing an electric latent image or a magnetic latent image in an electrophotographic method or an electrostatic printing method. The present invention relates to a color image forming method for multicolor electrophotography that significantly improves the image quality of color images.

[Prior art] Conventionally, as an electrophotographic method, the U.S. patent cylinder 2.297°69
Specification No. 1, Japanese Patent Publication No. 42-23910 (U.S. Patent No. 3.666, 363 specification), Japanese Patent Publication No. 43-247
Publication No. 48 (U.S. Patent No. 4,071,361)
Many methods are known, such as, but in general, a photoconductive substance is used to form an electrical latent image on a photoreceptor by various means, and then the latent image is transferred to developer powder (hereinafter referred to as toner). ), and after transferring the toner image to a transfer material such as paper as necessary, it is fixed by heat, pressure, a pressurized heat constant roller, solvent vapor, etc. to obtain a copy. In addition, if there is a step of transferring a toner image, usually
A step is provided to remove residual toner on the photoreceptor.

In recent years, there has been a rapid shift from monochrome copying to full-color copying in copying machines, and two-color copying machines and full-color copying machines are being extensively studied and put into practical use. For example, “Journal of Electrophotography Society J Vol 22. N
o, 1 (1983) and “Journal of Electrophotography Society J Vol.
25. No! , P52 (1986), there are also reports on color reproducibility and gradation reproducibility.

However, unlike television, photographs, and color printed matter, they cannot be immediately compared with the real thing, and for people who are used to seeing color images that are more beautifully processed than the real thing, the full-color electrophotographic images that are currently in practical use are not necessarily It has not been a satisfying experience.

Color image formation by full color electrophotography is 3 to -a.
All colors are reproduced using toner of three primary colors: yellow, magenta, and cyan.

In this method, light from the original is first passed through a color-separating light transmitting filter that has a complementary color to the toner color to form an electrostatic latent image on the photoconductive layer, and then the toner is transferred to the support through a development and transfer process. hold it. Repeat this process several times in sequence,
After overlapping the toners on the same support while adjusting the registration, a final full-color image is obtained by -times of fixing.

The developing method used at this time is U.S. Patent 2.61
Cascade development method described in No. 13.552, U.S. Patent No. 2
, 874,063, and other touchdown methods, among these methods, the most commonly used method is the magnetic brush method. This method uses magnetic particles such as steel and ferrite as carriers.

A developer consisting of toner and magnetic carrier is held by a magnet, and the magnetic field of the magnet arranges the developer in a brush shape. When the magnetic brush contacts the electrostatic latent image surface on the photoconductive layer, only toner is attracted from the brush to the electrostatic latent image and development occurs.

In general, in the case of a so-called two-component development system in which the developer is composed of toner and carrier, the developer charges the toner to the required charge amount and charge polarity by friction with the carrier, and uses electrostatic attraction to create a static image. The toner is used to develop an electric image, and therefore, in order to obtain a good visible image, it is necessary that the toner have good triboelectric charging properties, which is determined mainly by the relationship with the carrier.

Today, in response to the above-mentioned problems, we are searching for carrier core agents and carrier coating agents, optimizing the coating amount, examining charge control agents and fluidity imparting agents to be added to toner, and improving the base binder. Many studies have been conducted to achieve excellent triboelectric charging properties in all materials constituting the developer.

For example, as a technique for adding a charging aid such as chargeable fine particles to toner, Japanese Patent Publication No. 52-32256 and Japanese Patent Application Laid-open No. 56-64352 disclose fine resin powder having a polarity opposite to that of the toner. 6l-11i0760 proposes a technique in which fluorine-containing compounds are added to the developer to obtain stable triboelectric charging properties, and many charging aids are still being developed today.

Furthermore, various methods have been devised to add the above-mentioned charging aid. For example, a common method is to attach the charging aid to the surface of the toner particle using electrostatic force between the toner particles and the charging aid, van der Waals force, etc. , stirring,
A mixer etc. is used. However, in this method, it is not easy to uniformly disperse the additive on the surface of the toner particles, and the presence of additives that are not attached to the toner particles and become aggregates with each other and become so-called free. It is difficult to avoid. In such a case, the performance as a developer is affected. For example, the amount of triboelectric charge of the toner becomes unstable, resulting in inconsistent image density and images with a lot of fog.

Furthermore, when continuous copying or the like is performed, the content of the charging aid changes, making it impossible to maintain the initial image quality.

Another method of addition is to add a charging aid in advance together with a binder resin and a colorant during toner production. However, it is not easy to make the charge control agent uniform, and it is the substances near the surface of the toner particles that substantially contribute to the chargeability, and the charge aids and charge control agents present inside the particles have a chargeability. Therefore, it is not easy to control the amount of charging aid added or the amount of dispersion on the surface. Furthermore, even with toner obtained by such a method, the amount of triboelectric charge of the toner is unstable, and as mentioned above, it is not easy to obtain one that satisfies the developer characteristics, so it is not sufficient to use a charging aid. The reality is that products of satisfactory quality are not being obtained.

As a result of intensive studies on the environmental characteristics of the chargeability of negatively chargeable polyester color developers for electrostatic image development, the present inventor found that when at least one of the fluidizing agents is triboelectrically charged with the carrier used in the present invention, It has been found that a polyester color toner using a flow improver whose absolute value of charge amount is 20 μc/g or less has relatively excellent charge stability in various environments and provides good images without fogging. .

However, a sufficiently satisfactory image density cannot be obtained, and further improvements are desired.

Furthermore, in recent years, there has been an increasing demand in the market for high definition and high image quality in copying machines, and attempts have been made in this technical field to achieve high quality color images by reducing the particle size of toner. As the diameter becomes smaller, the surface area per unit weight increases, and the amount of charge on the toner tends to increase, leading to concerns about low image density and deterioration of durability. In addition, since the amount of charge on the toner is large, the adhesion between the toners is strong, resulting in a decrease in fluidity, which causes problems in the stability of toner replenishment and in applying triboelectricity to the replenishing toner.

Furthermore, in the case of color toner, since it does not contain a magnetic material or a conductive substance such as carbon black, there is no part that leaks charge, and the amount of charge generally tends to be large. This tendency is particularly noticeable when a polyester binder with high charging ability is used.

In addition, particularly for color toners, the following characteristics are strongly desired.

(1) The fixed toner needs to be almost completely melted to such an extent that the shape of the toner particles cannot be discerned, so that it does not diffusely reflect light and interfere with color reproduction.

(2) The colored toner must have transparency that does not interfere with toner layers of different tones below the toner layer.

(3) Each of the constituent toners must have well-balanced hue and spectral reflection characteristics and sufficient saturation.

From this point of view, many studies have been made regarding binder resins, but toners that satisfy all of the above characteristics have not yet been developed. Today, polyester-based resins are often used as color binder resins in this technical field, but toners made of polyester-based resins are generally easily affected by temperature and humidity. Problems such as insufficient charge amount occur under humid conditions, and there is an urgent need to develop a color developing method that has a stable charge amount even in a wide range of environments.

[Problems to be Solved by the Invention] An object of the present invention is to provide a negatively chargeable polyester color developing method for electrostatic charge development that solves the above-mentioned problems.

In other words, the purpose of this research is to
＜An object of the present invention is to provide a negatively chargeable polyester color developing method for electrostatic charge development which always has stable triboelectric chargeability.

A further purpose of this research is to provide a negatively chargeable polyester color developing method for electrostatic charge development that has clear image characteristics without capri and has excellent durability stability.

[Means and effects for solving the problems] The present invention provides an insulating non-magnetic color toner having a small amount of non-magnetic colorant-containing polyester resin particles and a fluidity imparting agent, and a carrier core material having a small amount (relative to the weight of the carrier core material). Using a negatively chargeable polyester color developer for electrostatic charge development consisting of a carrier coated with 0.05 to 10% by weight of an electrically insulating resin and having a weight average particle size of 25 to 65 μm, a latent layer is formed on the surface of the developer carrying member. Toner particles charged to the same polarity as the electrostatic latent image potential on the image bearing member and carrier particles charged to the opposite polarity to the toner particles are supported, and an alternating current component having an alternating current component and a direct current component is carried in the developing section. In the method of developing an electrostatic image on an electrostatic image carrier by forming an electric field, (1) the colorant-containing polyester resin particles have a volume average diameter of 6 to 11 μm; One is that when triboelectrically charged with a carrier, the absolute value of the charge amount is 20 μc/g or less, and the potential VL of the electrostatic image is
(V), the DC component Vac (V) of the alternating electric field of the same polarity, and the maximum electric field application point located opposite to the potential vt, m of the electrostatic image with respect to the DC component v, , m of the alternating electric field. The maximum electric field strength F (V/m) in the image area formed by the potential VPPMax (V) and the closest gap G (pm) between the surface of the developer carrying member and the surface of the electrostatic latent image carrier is F = −1/3i'ogH+ k and (where,
2.5≦k≦3.5, 0.15≦logH≦1.6
°H represents water vapor pressure [+nmHg1. ) A developing method is characterized in that it satisfies the following.

An example of a developing device according to the present invention will be explained with reference to FIG.

The latent image carrier 21 is a photosensitive drum having an outer diameter of 80 m5±1 ms+ and having a photoconductive insulating material layer such as OμC. The latent image carrier 21 is rotated in the direction of arrow a by a drive device (not shown). 22 is a developing sleeve having an outer diameter of 32 mm±1 mm that is close to or in contact with the latent image carrier 21, and is made of a non-magnetic material such as aluminum or 5OS316. The developing sleeve 22 has a right half-circumferential surface extending into the container 36 through a horizontally elongated opening formed in the lower left wall of the developing container 36 in the longitudinal direction of the container, and a left substantially half-circumferential surface exposed outside the container so as to be rotatably supported on a bearing. It is installed horizontally and is driven to rotate in the direction of the arrow.

Reference numeral 23 designates a fixed permanent magnet (magnet) as a fixed magnetic field generating means that is inserted into the developing sleeve 22 and positioned and maintained at the position and orientation shown in the figure. It remains fixed in its position. This magnet 23 has an N-pole magnetic pole 23a,
It has four magnetic poles: an S magnetic pole 23b, an N magnetic pole 23c, and an S magnetic pole 23d. The magnet 23 may be an electromagnet instead of a permanent magnet.

Reference numeral 24 has a base fixed to the side wall of the container on the upper edge side of the opening of the developer supply device in which the developing sleeve 22 is disposed, and the tip side is made to protrude inside the container 36 beyond the position of the upper edge of the opening and extend along the longitudinal direction of the upper edge of the opening. The blade is a non-magnetic blade that serves as a developer regulating member and is made by bending, for example, 5O3316 into a dogleg shape in cross section.

Reference numeral 26 denotes a magnetic particle limiting member whose upper surface is in contact with the lower surface side of the non-magnetic blade 24 and whose front end surface is a developer guide surface 261. A portion constituted by the non-magnetic blade 24, the magnetic particle limiting member 26, etc. is a regulating portion.

27 is a magnetic particle, and a ferrite particle with a resistance value of 10'Ωcm or more, preferably 10'ΩCff1 or more (maximum magnetization 55 to 75 emu/g) is coated with an electrically insulating resin of 0.05 to 10% by weight. It can be done.

Note that the resistance value of the magnetic particles is measured using a measuring electrode area of 4 cm2.
, using a sandwich type cell with an inter-electrode spacing of 4 cm, applying a voltage E (V/cm) between both electrodes under a pressure of 1 kg to one electrode, and measuring the current flowing through the circuit. The method used is to obtain the resistance value of the magnetic particles from

37 is a non-magnetic toner.

Reference numeral 40 denotes a sealing member for sealing the toner accumulated in the lower portion of the developer container 36, which is elastic and curved in the direction of rotation of the sleeve 22, and elastically presses the surface side of the sleeve 22. This sealing member 40 has an end on the downstream side in the rotational direction of the sleeve in a contact area with the sleeve so as to allow the developer to enter the inside of the container.

Reference numeral 60 denotes a toner replenishment roller that operates in response to an output obtained from a toner concentration detection sensor (not shown).

Examples of the sensor that can be used include a developer volume detection method, a piezoelectric element, an inductance change detection element, an antenna method using alternating bias, and an optical density detection method. The non-magnetic toner 37 is replenished by stopping the rotation of the roller.The fresh developer replenished with the toner 37 is mixed and stirred while being conveyed by the screw 61. Therefore, triboelectricity is applied to the replenished toner during this conveyance. Reference numeral 63 denotes a partition plate which is cut out at both ends in the longitudinal direction of the developing device, and the fresh developer conveyed by the screw 61 is passed to the screw 62 at this portion.

Further, the 5liii pole 23d is a transport pole. The recovered developer after development is collected into a container, and the developer in the container is further conveyed to a regulating section.

Further, near 23d, the fresh developer conveyed by the screw 62 provided close to the sleeve is exchanged with the recovered developer after development.

Reference numeral 64 denotes a conveying screw that equalizes the amount of developer in the axial direction of the developing sleeve.

Note that this configuration is also effective when magnetic particles and non-magnetic or weakly magnetic toner are mixed in the developer container.

The distance d2 between the end of the non-magnetic blade 24 and the surface of the developing sleeve 22 is a threshold of 300 to 1000μ, preferably 400μ.
~900uI11. If this distance is smaller than 300 μ■, magnetic particles, which will be described later, tend to clog between them, causing unevenness in the developer layer, and the developer necessary for good development cannot be applied, resulting in thin and uneven development. The drawback is that only images can be obtained. d2 is preferably 400 μm or more in order to prevent uneven coating (so-called blade clogging) due to unnecessary particles mixed in the developer.
If it is larger than 1000 μm, the amount of developer coated onto the developing sleeve 22 increases, making it impossible to regulate the thickness of the developer layer to a predetermined value, increasing the number of magnetic particles attached to the latent image carrier, and increasing the amount of developer applied as described below. This has the drawback that the circulation and development regulation by the developer limiting member 26 are weakened, and toner triboelectricity is insufficient, resulting in easy fogging.

Angle θ1 is -5@~35@, preferably 0@~25°
It is. When θ1 is 5°, the thin layer of developer formed by magnetic force, mirror force, cohesive force, etc. acting on the developer becomes sparse and uneven, and when θ>35@, the non-magnetic blade The amount of developer applied increases, making it difficult to obtain a predetermined amount of developer.

Even when the sleeve 22 is rotated in the direction indicated by the arrow, this magnetic particle layer maintains the magnetic force 9 and the restraining force based on gravity and the sleeve 22.
The movement slows down as it moves away from the sleeve surface due to balance with the conveying force in the direction of movement. Of course, some things fall due to the influence of gravity.

Therefore, the arrangement positions of the magnetic poles 23a and 23d and the magnetic particles 27
By appropriately selecting the fluidity and magnetic properties of the magnetic particle layer, the closer the magnetic particle layer is to the sleeve, the more it is transported toward the magnetic pole 23a, forming a moving layer. Due to the movement of the magnetic particles, the magnetic particles are conveyed to the development area as the sleeve 22 rotates and are subjected to development.

The movement of the magnetic particle layer is determined by the fluidity of the developer, the magnetic force, and the restraining force of the regulating member, but in the present invention, a magnetic member is provided in the regulating part to strengthen the magnetic restraining force.
The degree of compression of the developer in the regulation area is increased to enhance charge imparting ability. Therefore, the toner particles receive a greater impact from the magnetic particles or the developer carrying member. Therefore, polyester toner in particular tends to charge up when it receives an impact.

However, in the present invention, in order to solve the above problems and prevent the carrier from adhering to the latent image carrier while maintaining good fluidity and chargeability as a developer, at least one type of flow improver is used in the present invention. It is necessary to use a fluidity improver whose absolute value of charge amount is 20 μc/g or less when triboelectrically charged with the carrier used, and then to adopt the development method described below.

FIG. 2 explains the main part of the developing method according to the present invention, in which a developer containing a mixture of toner particles and carrier particles charged with the opposite polarity to the toner particles is transferred to an electrostatic image bearing member. This figure represents an alternating electric field when supplied to a developing section (nearest gap G (μm)) created by an electrostatic image carrier as , and a developer carrying member carrying this developer.

The alternating electric field in FIG. 2 has a rectangular wave shape.

The inventors conducted experiments assuming many patterns of reversal development methods, and found that the maximum electric field strength F (V
/μm) are the potential VL (V) of the electrostatic image, the DC component Voc (V) of the alternating electric field, and the AC component VPP of the alternating electric field.
Regarding (v), the potential Vt of the electrostatic image, (V) is the potential of the maximum electric field application point located on the opposite side to the DC component voc(v) of the alternating electric field and the potential of the electrostatic image 7 days V) The maximum electric field is given by the magnitude of , and the formula is formed by the nearest gap G (μm) between the surface of the developer supporting member and the surface of the electrostatic image carrier, VPP/21 + IVoc-Vt .

given by, F = -1/3 fogH + k Here, 2.5≦k≦3.5 0.15≦jogH≦1.6 H represents water vapor pressure [ma+Hgl.

It has been found that when it is set within the range of , there is no carrier adhesion, good gradation properties, and at the same time, high image density can be obtained.

When k<2.5, carrier adhesion and fogging are good, but line sharpness is impaired and image density is reduced.

On the other hand, when k>3.5, carrier adhesion increases, the latent image charge is disturbed, and image unevenness occurs.

Further, although carrier adhesion by persons other than carrier adherents to the image area occurs on the non-image area, in the present invention, it is also preferable to prevent carrier particles from adhering to the non-image area for the reasons stated above. This condition is such that toner particles do not adhere to the non-image area, and the non-image area potential Vo(
Even if VDC is variable, it is preferable that the DC component voc(v) with respect to VDC satisfies the following conditions.

That is, 70≦IVoc-Vbl≦220. Furthermore, since the non-image area potential may vary depending on the environment, it is preferable that this value is 200 (V) or less in order to increase reliability.

Furthermore, to add preferable conditions, it is preferable that the frequency ν (in) IZ) of the alternating electric field satisfies 1.0≦υ≦3.0.
If it exceeds , the sharpness and gradation of the line will deteriorate.

In the developing method of the present invention, the developer layer in the developing section may be in contact or non-contact without applying an alternating electric field.

Here, in the developing device and developer configured as described above, the relative volume ratio that defines the amount of developer conveyed to the development area will be explained. The relative volume ratio is a value defined in the developing section, that is, the portion where toner is transferred or supplied from the sleeve 22 to the photosensitive drum 1. Now, in this developing section, the application amount M (g/cm2
), the height of the developing section space h (cm), the true density of magnetic particles ρ (g/cm'), and the weight ratio of carrier particles on the sleeve surface c/(T+c)(%) (where, C is the carrier weight, T is the toner weight), the sleeve 22 and the photoreceptor 1
It is defined by the relative speed ratio σ and is expressed by the following formula.

Relative volume ratio Q = M/h x 1/ρx c/(r
+c) Distance between the end of the magnetic blade 24 and the surface of the sleeve 22! 1d2, which greatly affects the copied image, especially the image density.

The present inventors investigated the relationship between the relative volume ratio Q and image density under various experimental conditions, and found that by setting the relative volume ratio Q in the range of 15.0≦Q≦45.0, a good result was obtained. It has been found that color images can be obtained. Furthermore, it has been found that stable images can be obtained even when the atmospheric environment changes when Q is within the above range.

The above conditions proposed as a preferred developing method in the present invention are such that the image density increases or decreases as the amount of developer applied onto the sleeve 22 and the space in the developing section increase or decrease.
The image quality does not change monotonically, but when the relative volume ratio Q as the temporal abundance of magnetic particles in the development space is 15.
A sufficient and stable image density can be obtained in the range of 0 to 45.0%, and if it is less than 15.0% or exceeds 45.0%, a slight decrease in image density and image quality will occur, which are undesirable for color image reproduction. However, this is based on the discovery that neither sleeve ghost nor fogging occurs within the range of the above-mentioned numerical values, which provide sufficient image quality.

If the relative volume ratio is in the range of 15.0 to 45.0%,
The spikes formed on the surface of the sleeve 22 are formed in a preferably sparse state, and both the toner on the sleeve 22 and the spikes are sufficiently exposed to the photosensitive drum 1, and the toner 100 on the sleeve is also exposed to the alternating electric field. Because of the flying transfer, almost all of the toner is available for development, resulting in high development efficiency (ratio of toner that can be consumed for development out of the toner present in the development area) and high image density. It will be done. Preferably, a minute but strong vibration of the spike is generated, thereby loosening the magnetic particles 27 and the toner 100 adhering to the sleeve 22. In any case, it is possible to prevent uneven sweeping and ghost images that occur in the case of magnetic brushes. Furthermore, due to the vibration of the ears, the magnetic particles 2
Since the frictional contact between 7 and toner 28 becomes active, toner 2
It is possible to improve the frictional charging of 8 and prevent the occurrence of fogging.

It is preferable that the relative volume ratio Q is within the range of the above values, and more preferably, the relative velocity ratio a is 1.2<
It is better to set σ≦3.0, which means that the sleeve 22
By varying the relative speed between the photoreceptor 1 and the photoreceptor 1, unnecessary fog toner and carrier adhering to the photoreceptor 1 can be recovered into the developing device using mechanical friction, and the relative speed ratio This is because by setting the value of 1.2 or more, there are effects such as being able to increase development efficiency. However, if the volume ratio is increased under the setting of σ>3.0, the above-mentioned re-gathering effect is too strong, which tends to cause brush marks and a decrease in density. Further, by setting σ≦3.0, it is possible to prevent toner from scattering outside the developing device during development. Further, when σ>3.0, the density within the solid portion of the copied image is not uniform, and so-called "shaking" is likely to occur.

In the present invention, polyester resin is preferable as the binder resin.

In particular, the following formula % formula %) (wherein R is an ethylene or propylene group, x,
Each y is an integer of 1 or more, and the average value of x+y is 2 to 10. ) as a diol component, and a carboxylic acid component consisting of a bivalent or higher carboxylic acid, its acid anhydride, or its lower alkyl ester (e.g., fumaric acid, maleic acid, maleic anhydride, phthalate). It is more preferable to use a polyester resin obtained by cocondensation-polymerizing at least a polyester resin with an acid such as terephthalic acid, trimellitic acid, pyromellitic acid, etc., since it has sharp melting characteristics.

In particular, in terms of permeability with traben, the apparent viscosity at 90°C is 5 x 1 G' to 5 x tG' poise, preferably 25 x 10' to 2 x 10' poise, more preferably 10'-IQ' poise. 1 (the apparent viscosity at 10° C. is 10' to 5 x 10' voids, preferably 104 to 3, Q x 10' voids, more preferably 104 to 2 x 10' voids, and the permeability Good color 〇) IP is obtained, and even as a full color toner, good results are obtained in fixing properties, color mixing properties, and high temperature offset resistance.

In particular, the absolute value of the difference between the apparent viscosity P1 at 90°C and the apparent viscosity P2 at 100°C is 2X10'<Pl-P2
It is preferably in the range I < 4 x 10'.

When made into fine particles using these resins, most exhibit negative chargeability even without the use of a charge control agent, and can be used as is in the present invention, but it is preferable to use charge control that imparts negative chargeability. In this case, it is preferable to use a colorless or light-colored charge control agent that does not affect the color tone of the toner. Examples of negative charge control agents include metal complexes of alkyl-substituted salicylic acids (e.g. di-tertiary charge control agents). Organometallic complexes such as chromium complexes or zinc complexes of butylsalicylic acid can be mentioned. When a negative charge control agent is added to the toner, it is added in an amount of 0.00% per 100 parts by weight of the binder resin.
It is good to add 1 to 10 parts by weight, preferably 0.5 to 8 parts by weight.

When preparing a two-component developer by mixing with the toner according to the present invention, the mixing ratio is 2 as the toner concentration in the developer.
．． Good results are usually obtained with an amount of Ofi between % and 11% by weight, preferably between 3% and 9% by weight. If the toner concentration is less than 2.0%, the image density will be too low to be practical;
% or more increases fogging and in-machine scattering, shortening the useful life of the developer.

As the coloring agent used in the present invention, a wide variety of known dyes and pigments can be used, such as phthalocyanine blue, industhrene blue, peacock blue, permanent red, lake red, rhodamine lake, banza yellow, permanent yellow, benzine yellow, and the like. The content thereof is 12 parts by weight or less, preferably 0.5 to 9 parts by weight, based on 100 parts by weight of the binder resin so as to sensitively reflect the permeability of the IP film.

The flow improver used in the present invention has an absolute value of electrification of 20 μc/cm when triboelectrically charged with the magnetic particles used in the present invention.
It is necessary to contain at least one type of material with an amount of at most 10 μc/g, preferably at most 10 μc/g. This is because even if the charging ability of the binder resin is stabilized as in the present invention, if silicic acid fine powder, which is commonly used as a flow improver, is used alone, the fluidity will certainly improve. As for the charging characteristics, charging tends to be excessive especially under low humidity, and as a result, the environmental stability of the toner is impaired. This tendency becomes more pronounced as the particle size of the toner becomes smaller and the amount of flow improver used increases.

However, as in the present invention, by incorporating at least one flow improver having a weak charging ability as a flow improver, it was possible to achieve both charging characteristics and fluidity.

Examples of such particles include, but are not necessarily limited to, the following: For example, ^
zOs, T102, GeO2, Zr(h, 5C2
Metal oxides such as 03°HfO, SIC, Tic, etc.
Carbide such as W2C and Si3N4. There are nitrides such as Ge5N4, among which ^j, 0. ．． T.I.O.
5c20a, ZrO2, GeO2, and HfO2 are colorless or white and are suitable for use in color toners without adversely affecting the color. Also especially 81) 203. TIO, . . . ZrO2 is more preferable because it can be easily produced with a suitable particle size by a gas phase method. In addition, the smaller the particle size of the particles to be added, the better, and in the present invention, the specific surface area measured by the BET method is 30102/g to 300 m'/g.
Use a fluidity imparting agent in the range of g. More preferably, it is 50 II + 27 g or more, and the finer the particle size, the better the toner fluidity characteristics.

If necessary, additives may be mixed into the toner of the present invention within a range that does not impair the properties of the toner. Examples of such additives include lubricants such as Teflon, zinc stearate, and polyvinylidene fluoride; Or a fixing aid (e.g. low molecular weight polyethylene, low molecular weight polypropylene, etc.)
etc.

When producing the toner of the present invention, heat rolls, kneaders, etc.
, a method of kneading the constituent materials well with a heat kneader such as an extruder, followed by mechanical crushing and classification;
Alternatively, a material such as magnetic powder is dispersed in a binder resin solution and then spray-dried, or a predetermined material is mixed with the monomers that should constitute the binder resin, and the emulsified suspension is obtained. Each method can be applied, such as a polymerized toner production method in which a toner is obtained by polymerizing.

The particle size of the flow improver used in the present invention is 4 to 4 in terms of volume average diameter.
It is preferable that the particle size is 10 μI and that the volume distribution of coarse particles of 16.0 μm or more is 1.0% or less. Further, in the case of a spherical toner such as a polymerized toner, the volume average diameter is preferably 3 to 10 μm. Since the toner used in the present invention has a fine particle size, the toner adheres faithfully to a minute electrostatic latent image, and there is little disturbance in the toner adhesion at the end of the electrostatic latent image.

As a result, an image with high resolution and good color reproducibility can be obtained. In particular, photographic images have many halftone areas, which are collections of minute latent images, and the effect of particle size is even more apparent, resulting in a good image.

The coating resin on the surface of the magnetic particles varies depending on the toner material and the carrier core material, but in the present invention, at least acrylic acid (or its ester) monomer is used to improve adhesion to the carrier core surface. and methacrylic acid (or ester thereof) monomer. In particular, when polyester resin particles with high negative charging ability are used as toner materials, it is preferable to use a copolymer with a styrene monomer in order to stabilize charging, and the copolymerization weight of the styrene monomer is Preferably, the ratio is 5 to 70% by weight.

The average molecular weight of the above copolymer is determined to be a number average molecular weight of 10.
00-35,000 preferably 17,000-24.0
00. Weight average molecular weight is 25,000 to 100,00
0, preferably 49,000 to 55,000.

Coating resin connector for carrier core material that can be used in the present invention
Examples of styrene-based polymers include styrene monomer, chlorostyrene monomer, α-methylstyrene monomer, styrene-chlorostyrene monomer, and examples of acrylic-based polymers include acrylic acid ester monomer (methyl acrylate monomer). -Ethyl acrylate monomer Butyl acrylate monomer Octyl acrylate monomer Phenyl acrylate monomer
There are methacrylic acid ester monomers (methyl methacrylate, ethyl methacrylate monomer, butyl methacrylate monomer, phenyl methacrylate monomer), etc.

As the magnetic particles used in the present invention, for example, surface-oxidized or unoxidized metals such as iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earths, and their alloys or oxides can be used. Further, there are no special restrictions on the manufacturing method.

Each measurement method (1) to (3) of the present invention will be described below.

(1) Particle size distribution measurement: A Coulter counter TAiI model (manufactured by Coulter Co., Ltd.) was used as the measuring device, an interface (manufactured by Nikkaki) that outputs a number average distribution and a volume average distribution, and a CX-I personal computer (Canon). ) is connected, and the electrolyte is 1% NaCj! using primary sodium chloride. Prepare an aqueous solution.

As a measuring method, 0.1 to 51 IIj of a surfactant, preferably an alkylbenzenesulfonate salt, as a dispersant is added to 100 to 150 mR of the electrolytic aqueous solution, and 0.5 to 50 mg of the measurement sample is added.

The electrolyte in which the sample was suspended was dispersed for about 1 to 3 minutes using an ultrasonic disperser, and the particle size distribution of particles of 2 to 40 μ was measured using the Coulter Counter T^-II type using a 100 μ aperture. Measure volume average distribution 1
Find the number average distribution.

From the volume average distribution 1 number average distribution thus determined, a multi-value of 9 volume average particle diameters of 6.35 μ or less for the number average distribution and 20.2 μ or more for the volume average distribution is obtained.

(2) Frictional charge measurement: The measurement method will be explained in detail using drawings.

FIG. 3 is an explanatory diagram of an apparatus for measuring the amount of triboelectric charge of toner. First, a mixture of toner and carrier whose weight ratio is 50 to 1 is placed in a metal measuring container 12 with a 500 mesh screen 13 at the bottom.
00mJ! Place in a polyethylene bottle with a capacity of about 10
Shake by hand for ~40 seconds, the mixture (developer) will be approximately 0.5 ~
Add 1.5 g and cover with metal lid 14. The weight of the entire measurement container 12 at this time is taken as L (g).Next, in the suction device 11 (at least the part in contact with the measurement container 12 is an insulator), suction is carried out from the suction port 17 and the air volume control valve 16 is turned on. Adjust the pressure on the vacuum gauge 15 to 250■^q. In this state, suction is performed for a sufficient period, preferably 2 minutes, to remove the toner by suction. The potential of the electrometer 19 at this time is V (volt)
Here, 18 is a capacitor and the capacitance is C(μ
F). Furthermore, the weight of the entire measurement container after suction is weighed and is defined as W2 (g). The amount of triboelectric charge of this toner (μc
/g) is calculated as shown below.

(However, the measurement conditions are 23°C and 60% RH.) The carrier used for the measurement is a fluororesin-styrene resin coated ferrite carrier containing 70 to 90% by weight of carrier particles of 250 mesh bath and 350 mesh. . That is, vinylidene fluoride-tetrafluoroethylene copolymer and styrene-acrylic acid 2
A ferrite carrier coated with 0.2-0.7% by weight of a 5:5 mixture of -ethylhexyl-methyl methacrylate is used.

The sample toner and carrier used in the measurement were at 23°C.

After being left in a 60% RH environment for at least 12 hours, it is used to measure the amount of charge.

Further, the measurement of the amount of triboelectric charge is performed in an environment of 23° C. and 60% RH.

(3) Apparent viscosity measurement: Flow tester CFT-500 model (manufactured by Shimadzu Corporation) is used. The sample is approximately 1.0-1.5g of 60 mesh pass product.
Weigh. Use a molding machine to make this into 100kg/cm'
Pressure is applied for 1 minute with a load of .

This pressurized sample is subjected to flow tester measurement under the following conditions at room temperature (temperature: 20 to 30° C., humidity: 30 to 70% RH) to obtain a humidity-apparent viscosity curve. From the obtained smooth curve, the apparent viscosity at 90° C. and 100° C. is determined, and this is used as the apparent viscosity with respect to the temperature of the sample.

RATE TEMP 6. O07M ('
C1 minute) SET TEMP 70. ODE
G (t) MAX TEMP 200
．． ODEGINTERVAL 3. O.D.
EGPREHEAT 300. OSEC(
seconds) LO^0 20.0 to GF (k
g) DIE (DIA) 1.0 MM
(mm) DIE (LENG) 1.0
MMPLuNGER1, OCM"(cm') [Example] Phthalocyanine pigment sTL After thoroughly mixing the materials in a Henschel mixer, melt-kneading them twice in a Miki roll mill, and after cooling, using a hammer mill. It was coarsely ground to a particle size of approximately 1 to 2 mm.

Then, it was pulverized using an air jet type pulverizer. Furthermore, the obtained finely pulverized product was classified using a multi-division classifier to obtain a cyan colored resin powder having a volume average particle size of 8.1 μm.

100 parts by weight of the above colored resin particles, 0.3 parts by weight of alumina fine powder with a specific surface area of 95 m27 g and a charge amount of 12 μc/g by the BET method, and a specific surface area of 230 m by the BET method.
A cyan toner was prepared by mixing with 0.5 parts by weight of silica fine powder having a charge amount of -75 μc/g which had been hydrophobized with hexamethyldisilazane and had been hydrophobized with hexamethyldisilazane.

The surface of Cu-Zn was coated with 5 parts by weight of this cyan toner and a styrene-methyl methacrylate-2-ethylhexyl acrylate copolymer (copolymerization weight ratio = 45:35:20) (coating amount 0.5% by weight). -95 parts by weight of Fe-based ferrite particles were mixed to prepare a two-component developer.

Next, using the above developer, the first developer was prepared with a gap of 800 μ between the developing sleeve and the cutting blade, which had a diameter of 32 mm.
The developing device shown in the figure was installed in a modified Canon color laser copier PIXEL, which uses a digital development method and a reversal development method.
μ) and the surface of the sleeve 22 was defined as SOOμ.

The peripheral speed ratio between the photosensitive drum and the developing sleeve was 1.7, and the relative volume ratio of the magnetic particles was Q = 31.5. As a bias power supply, the frequency is 2000 Hz, and the peak-to-peak value is 2.
Development was carried out using an AC voltage of 000 V superimposed with a DC voltage.

The maximum electric field strength F is 20°C/10% as k -2,9
Below F = 2.82V/μm+ (H = 1.75m
mHg) F = 2.43V/μo at 30℃/80%
+ (H = 25.4 mml 1 g) 22.5°C 150%
Below F = 2.55V/μm (H = 10.2mm
Hg).

When images were produced in three environments using the above combination, the image density was 1.45 at 20℃/10%, the image density was 1.50 at 30℃/80%, and the image density was 1.51 at 22.5℃/150%. Very stable image density was achieved, and very good images were obtained with no fogging or adhesion of magnetic particles.

Furthermore, when a photographic original was imaged, an image with very good highlight gradation was obtained.

Furthermore, when continuous durability was carried out for 5,000 sheets in each environment, an image with an image density of 1.45 to 1.60 and excellent highlight gradation was obtained in each environment.

When the same procedure as in Example 1 was carried out except for setting k = 3.8 in Example 1, the image density was as high as 1.85 at 30°C/80%, and the scattering phenomenon during fixing was reduced. It was slightly lower than in Example 1. Furthermore, the gradation was also slightly degraded.

So I lowered the toner density to 4% and this time it was 2%.
At 0° C./10%, carrier adhesion occurred and the fog level worsened, making it impossible to achieve a satisfactory combination in each environment.

Comparative Example 2 Example 1 except that in Example 1, =2.2 was set.
When the same procedure was carried out as above, the image density was as low as 1.30 at 20° C./10%.

Therefore, when I increased the toner concentration to 6%, the temperature was 20℃/
The environmental disparity has widened compared to Example 1: 1.42 at 10%, 1.57 at 30°C/80%, and 1.49 at 150% at 22.5°C. Furthermore, the sharpness of the line was slightly reduced compared to Example 1 at 30° C./80%.

■In Example 1, a developer was prepared in the same manner as in Example 1 except that fine alumina powder was not used, and the electric field strength was set to 3.
When the image density was set to 5 and carried out in the same manner as in Example 1, the image density was 1.35 at 20°C/10%, the image density was 1.60 at 30°C/80%, and the image density was 1.52 at 22.5°C and 150%. and environmental disparities have widened.

JC Tsujil A magenta toner was prepared in the same manner as in Example 1 except that 3 parts of a rhodamine pigment was used instead of the phthalocyanine pigment. 4 parts of this magenta toner and 96 parts of ferrite particles used in Example 1 were mixed,
A two-component developer was prepared.

When the electric field strength was set to 3.1 and image output was performed in the same manner as in Example 1, the image density was high in the range of 1.50 to 1.65 in each environment, with no highlight gradation, fogging, or carrier adhesion. The results were also good as in Example 1.

In Example 1, a two-component developer was prepared by mixing 6 parts by weight of cyan toner and 94 parts by weight of ferrite particles.

When the image was produced in the same manner as in Example 1 with the maximum electric field strength set to 2.7, the image density was 1.50 at 20°C/10%, and 1 at 30°C/80%. .58 At 22.5°C and 150%, a very good image with an image density of 1.52 was obtained as in Example 1.

In addition, Fig. 4 shows the maximum electric field strength F of each example and comparative example.
and water vapor pressure H data are shown together.

Actual JLfL Hill In Example 1, 0.4 parts by weight of +5 μc/g titanium oxide fine powder was used instead of alumina, and the electric field strength F
When the same procedure as in Example 1 was carried out except for setting = -172jo3H+ 3.4, good results were obtained as in Example 1.

[Effects of the Invention] The present invention is not easily influenced by environments such as temperature and humidity, has stable triboelectric charging properties, and can obtain images that are clear and have excellent durability and stability.

[Brief explanation of drawings]

FIG. 1 shows an example of the developing device according to the present invention, FIG. 2 is a diagram explaining the main part of the developing method according to the present invention, and FIG. 3 is an explanatory diagram of a device for measuring the amount of triboelectric charge. FIG. 4 illustrates data on maximum charge strength (F) and water vapor pressure (H) for each example and comparative example.

Claims (3)

[Claims] (1) An insulating nonmagnetic color toner having at least nonmagnetic colorant-containing polyester resin particles and a fluidity imparting agent, and 0.05 to 10% by weight based on the weight of the carrier core material.
Weight average particle size 25-65μ coated with electrically insulating resin
Using a negatively charged polyester color developer for electrostatic charge development consisting of a carrier, toner particles charged to the same polarity as the electrostatic latent image potential on the latent image carrier, and toner particles on the surface of the developer carrying member. A method of developing an electrostatic image on an electrostatic image carrier by supporting carrier particles charged with a polarity opposite to that of the electrostatic image carrier and forming an alternating electric field having an alternating current component and a direct current component in a developing section, [a] The colorant-containing polyester resin particles have a volume average diameter of 6 to 11 μm, and when at least one of the fluidity imparting agents is triboelectrically charged with a carrier, the absolute value of the charge amount is 20 μc/ g or less, and the potential V_L (V) of the electrostatic image in [b] and the DC component of the alternating electric field of the same polarity V_
D_C (V) and the DC component of the alternating electric field V_D_C (V)
The potential V_P_PMax (V) at the point of maximum electric field application, which is located opposite to the potential V_L (V) of the electrostatic image, and the closest gap G between the surface of the developer carrying member and the surface of the electrostatic latent image carrier.
(μm) The maximum charge strength F of the image area formed by
(V/μm) is F=-1/3logH+k and (where 2.5≦k≦3.5, 0.15≦logH≦
1.6, H represents water vapor pressure [mmHg]. ) F=|V_P_PMax/2|+|V_D_C-V_L
A developing method characterized by satisfying |/G. (2) The developer carrying member has a diameter of 600 mm in the developing area.
It is a member with an outer diameter of 32 mm ± 1 mm that includes a magnetic roller having a strength of ~1200 Gauss, and the latent image carrier has an organic layer thickness of 15 mm with a charge transfer layer on the surface.
The developing method according to claim 1, characterized in that it is made of an organic photoconductive semiconductor having an outer diameter of 80 mm±1 mm, which is 35 μm. (3) The carrier core material is 98% or more Cu-Zn-
Fe (metal composition ratio (5-20): (5-20): (30
It is a ferrite carrier consisting of a composition of ~80)),
3. The developing method according to claim 1, wherein the carrier particles smaller than 11 μm are present in an amount of 0.5% by weight or less.