JP2003122045A - Developing device, image forming apparatus, toner and computer system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a developing device, etc., for forming high quality images by using a toner containing toner particles with small particle diameters. SOLUTION: In the developing device provided with toner with base particles and externally added particles and a toner carrier moving while carrying this toner and developing latent images carried by an image carrier, the number of the base particles to which the externally added particles are not attached is <=15% of the total number of base particles of the toner.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

2. Description of the Related Art Various types of devices such as printers, copiers and facsimiles are known as image forming devices for forming images on various media such as paper, cloth, film and the like. In some cases, toner is used to form an image on a medium.

There are various methods for producing this toner, such as a pulverization method and a polymerization method. However, no matter what production method is used, the particle diameter of the toner particles produced is within a certain range. Some toner particles have a relatively large particle size, and some have a relatively small particle size. If the toner particles have different particle diameters, the charging characteristics,
Various characteristics such as heat absorption characteristics are different.

Therefore, in order to form a high quality image by using toner, it is necessary to firmly manage the state of each toner particle including the toner particles having a small particle diameter of about 1 micron.

From this point of view, the particle size distribution of toner is widely measured, and a method called a small hole passage method (Coulter method) is often used as the measuring method. As a device employing this measuring method, Coulter Multisizer, etc. are commercially available. In this small hole passage method, toner particles are dispersed and suspended in an electrolyte solution to form partition walls with pores as shown in FIG. 7, and voltage is applied to both ends of the partition walls to suspend them in the measurement pores (aperture). When the turbid liquid is passed, the electrolyte in the pores is reduced by the volume of the toner particles in the liquid when passing through the pores, so that the electric resistance is increased. This resistance change is observed as a voltage pulse, and the volume-based particle size distribution is obtained by measuring this pulse.

In addition, a scanning electron microscope (SEM: Scan)
It is also widely used to observe the state of each toner particle using a ning electron microscope).

[0006]

However, the above-mentioned small hole passage method is merely a method for measuring the particle size of toner particles, and moreover, it is more than the size of the measuring pores (aperture size). If the toner particles are too small, the measurement will be inaccurate. Depending on the size of the pores, the particle size is 1
For toner particles smaller than micron, it may not appear on the data at all.

Further, a scanning electron microscope (SEM: Scan)
The ning electron microscope) is merely an apparatus for observing toner particles from the outside, and is not suitable for quantitatively analyzing the physical properties of each toner particle.

Therefore, in order to form a high-quality image using a toner containing toner particles having a small particle diameter, it is necessary to accurately analyze toner particles having a particle diameter of about 1 μm. Furthermore, for each toner particle including such small toner particles, not only the particle size but also the physical properties such as the adhesion state of the external additive to the mother particles are quantitatively analyzed to obtain a preferable state as a whole toner. Need to be.

The present invention has been made in view of the above problems, and an object thereof is a developing device for forming a high quality image by using a toner containing toner particles having a small particle diameter, It is to realize an image forming apparatus, a toner, and a computer system.

[0010]

In order to solve the above-mentioned problems, the present invention mainly comprises a toner having mother particles and external additive particles, and a toner carrier which carries and moves the toner. In a developing device for developing a latent image carried on an image carrier, the number of mother particles to which external additive particles are not attached is 15% or less of the total number of mother particles of the toner. Characterize.

Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS At least the following will be made clear by the description in the present specification and the accompanying drawings.

In a developing device having a toner having mother particles and external additive particles and a toner carrier for carrying the toner and moving the latent image carried on the image carrier, The developing device, wherein the number of the mother particles to which the external additive particles are not attached is 15% or less of the total number of the mother particles of the toner.

According to such a developing device, it is possible to prevent the phenomenon in which the toner particles having adhesiveness remain on the toner carrier, and to use a toner containing toner particles having a small particle size. And a developing device for forming a high quality image can be realized.

Further, in such a developing device, the mother particles may contain a release agent.

According to such a developing device, it becomes possible to prevent the toner particles having a high adhesiveness due to having the releasing agent from strongly adhering to the surface of the toner carrier.

In the developing device, the release agent may be incompatible with the mother particles.

According to such a developing device, it is possible to prevent the toner particles, which are incompatible with the mother particles and thus have higher tackiness, from strongly adhering to the surface of the toner carrier. Is possible.

In the developing device, the mother particles may be manufactured by a pulverizing method.

When mother particles having an incompatible mold release agent (WAX) are produced by a pulverization method, the mold release agent is easily exposed on the surface of the mother particles, and the exposed mold release agent causes toner particles to be released. Tend to adhere strongly to the surface of the toner carrier, but since the proportion of the mother particles to which the external additive particles do not adhere is 15% or less, the toner particles adhere to the surface of the toner carrier. It becomes possible to effectively suppress strong adhesion.

Further, in such a developing device, the tip of the layer thickness regulating member is not in contact with the toner carrier, and the portion apart from the tip by a predetermined distance is in contact with the toner carrier. The contact position may be below the rotation center position of the toner carrier.

The tip of the layer thickness regulating member is not in contact with the toner carrier, and the portion apart from the tip by a predetermined distance is in contact with the toner carrier, and the contact position is the toner carrier. When it is below the rotation center position of the carrier, the toner particles are strongly adhered to the surface of the toner carrier. However, as described above, since the proportion of the mother particles to which the external additive particles are not attached is 15% or less, it is possible to prevent the toner particles from strongly attaching to the surface of the toner carrier. It will be possible.

Further, the developing device has a rotatable toner supply member for supplying the toner to the toner carrier, and the rotation direction of the toner supply member is opposite to the rotation direction of the toner carrier. It may be a direction.

When the rotation direction of the toner supply member is opposite to the rotation direction of the toner carrier, the toner particles are strongly adhered to the surface of the toner carrier. However, as described above, since the proportion of the mother particles to which the external additive particles are not attached is 15% or less, it is possible to prevent the toner particles from strongly attaching to the surface of the toner carrier. It will be possible.

Further, in such a developing device, there is provided a seal member which is in contact with the toner carrier for preventing the leakage of the toner in the developing device, and the contact position is at the contact position of the toner carrier. It may be above the rotation center position of.

When the contact position of the seal member with the toner carrier is higher than the rotation center position of the toner carrier, the toner particles adhere strongly to the surface of the toner carrier. Is promoted. However, as described above, since the proportion of the mother particles to which the external additive particles are not attached is 15% or less, it is possible to prevent the toner particles from strongly attaching to the surface of the toner carrier. It will be possible.

Further, in such a developing device, there is provided a toner accommodating portion for accommodating toner, the toner supply member is arranged below the toner accommodating portion, and the toner accommodated in the toner accommodating portion is It may be a developing device that is supplied to the toner carrier by the toner supply member below the toner storage portion.

A toner supply member is disposed below the toner storage portion, and the toner stored in the toner storage portion is supplied to the toner carrier by the toner supply member below the toner storage portion. In that case, strong adhesion of the toner particles to the surface of the toner carrier is promoted. However, as described above, since the proportion of the mother particles to which the external additive particles are not attached is 15% or less, it is possible to prevent the toner particles from strongly attaching to the surface of the toner carrier. It will be possible.

Further, a developing device having a toner having mother particles and external additive particles, and a toner carrier for carrying and moving the toner, for developing a latent image carried by the image carrier. In, the number of the mother particles to which the external additive particles are not attached is 15% or less of the total number of the mother particles of the toner, and the mother particles are incompatible with the mother particles. And the mother particles are manufactured by a pulverization method, the tip of the layer thickness regulating member is not in contact with the toner carrier, and the portion separated from the tip by a predetermined distance is the toner. In contact with the carrier, the contact position is below the rotation center position of the toner carrier, and has a rotatable toner supply member for supplying toner to the toner carrier,
The rotation direction of the toner supply member is opposite to the rotation direction of the toner carrier, and the seal member is in contact with the toner carrier to prevent the toner from leaking in the developing device. The contact position is above the rotation center position of the toner carrier, and has a toner storage portion for storing toner, and the toner supply member is disposed below the toner storage portion. The toner accommodated in the toner accommodating portion is supplied to the toner carrier by the toner supply member below the toner accommodating portion. According to such a developing device, although the toner particles are extremely easily attached to the surface of the toner carrier, the proportion of the mother particles to which the external additive particles are not attached is 15% or less. Therefore, the adhesion of the toner particles to the surface of the toner carrier is suppressed.

An image forming apparatus equipped with such a developing device can also be realized.

According to such an image forming apparatus, it is possible to prevent the toner particles from strongly adhering to the surface of the toner carrier, and as a result, it is possible to form a high quality image.

Further, it has a toner carrier that carries and moves toner, and is used in a developing device for developing a latent image carried by an image carrier, and has mother particles and external additive particles. In the toner, the number of mother particles to which the external additive particles are not attached is
The toner is 15% or less of the total number of mother particles of the toner.

With such a toner, it is possible to prevent the toner particles from strongly adhering to the surface of the toner carrier.

Further, the computer main body, the display device, the input device, the toner having the mother particles and the external additive particles, and the toner carrier for carrying the toner to move the image carrier are provided. In a computer system equipped with an image forming apparatus equipped with a developing device for developing a carried latent image,
The computer system, wherein the number of mother particles to which the external additive particles are not attached is 15% or less of the total number of the mother particles of the toner.

According to such a computer system, it is possible to prevent the toner particles from strongly adhering to the surface of the toner carrier, and as a result, it is possible to form a high quality image, which is better than in the past. It becomes possible to realize an excellent computer system.

=== Outline of Image Forming Apparatus (Laser Beam Printer) === Next, with reference to FIG. 1, an outline of the laser beam printer 10 will be described as an example of the image forming apparatus. FIG. 1 is a diagram showing the main constituent elements of the laser beam printer 10. Note that, in FIG. 1, the up and down directions are indicated by arrows, and for example, the paper feed tray 92 is
The fixing device 90 is arranged below the laser beam printer 10, and the fixing device 90 is arranged above the laser beam printer 10.

As shown in FIG. 1, the laser beam printer 10 according to the present embodiment has a charging device 30, which is arranged along the rotating direction of a photoconductor 20 which is a latent image carrier for carrying a latent image.
It has an exposure device 40 and a YMCK developing device 50.
Primary transfer device 60, intermediate transfer member 70, secondary transfer device 8
0 and the fixing device 90.

The photoconductor 20 has a cylindrical conductive base material and a photosensitive layer formed on the outer peripheral surface thereof, and is rotatable about the central axis. In the present embodiment, it is shown in FIG. Rotate clockwise as shown by the arrow.

The charging device 30 is a device for charging the photoconductor 20, and the exposure device 40 is a device for forming a latent image on the charged photoconductor 20 by irradiating a laser. The exposure device 40 has a semiconductor laser, a polygon mirror, an F-θ lens, and the like, and charges a modulated laser based on an image signal input from a host device (not shown) such as a personal computer or a word processor. The exposed photoconductor 20 is irradiated.

The YMCK developing device 50 develops the latent image formed on the photoconductor 20 using yellow (Y) toner, magenta (M) toner, cyan (C) toner, and black (K) toner. It is a device for.

The YMCK developing device 50 includes a black developing device 52a containing black (K) toner, a magenta developing device 52b containing magenta (M) toner, and
A cyan developing device 52c containing cyan (C) toner,
Further, it has a yellow developing device 52d containing a yellow (Y) toner. These four developing devices are configured so as to be rotatable about the central axis.
Each time 0 rotates one revolution, the latent image formed on the photoconductor 20 is selectively opposed to the photoconductor 20 by the toner contained in each developing device. The details of each developing device will be described later.

The primary transfer device 60 is a device for transferring the monochromatic toner image formed on the photosensitive member 20 to the intermediate transfer member 70. The intermediate transfer member 70 is an endless belt, and is rotationally driven at the same peripheral speed as the photosensitive member 20. The secondary transfer device 80 is a device for transferring the full-color toner image formed on the intermediate transfer member 70 to a recording medium such as paper, film, cloth or the like. The fixing device 90 is a device for fusing a full-color toner image transferred onto a recording medium to a medium such as paper to form a permanent image.

Next, the operation of the laser beam printer 10 thus constructed will be described with reference to other components.

First, when an image signal from a host device (not shown) is input to the laser beam printer 10, the photoconductor 2
0, the developing roller as a toner carrier provided in each developing device, and the intermediate transfer body 70 rotate. Photoconductor 20
Are sequentially charged by the charging device 30 at the charging position while rotating.

The charged area of the photoconductor 20 is equal to that of the photoconductor 2.
With the rotation of 0, the exposure position is reached, and the exposure device 40 forms a latent image corresponding to the image information of the first color, for example, yellow Y, in the area. In addition, the YMCK developing device 5
0 positions the yellow developing device 52d containing the yellow (Y) toner at the developing position facing the photoconductor 20.

The latent image formed on the photoconductor 20 reaches the developing position as the photoconductor 20 rotates and is developed with yellow toner by the yellow developing device 52d. As a result, a yellow toner image is formed on the photoconductor 20.

The yellow toner image formed on the photoconductor 20 reaches the primary transfer position as the photoconductor 20 rotates,
The image is transferred to the intermediate transfer member 70 by the primary transfer device 60. At this time, a primary transfer voltage having a polarity opposite to the charging polarity of the toner is applied to the primary transfer device 60. During this time, the secondary transfer device 80 is separated from the intermediate transfer body 70.

By repeating the above processing for the second color, the third color, and the fourth color, the toner images of four colors corresponding to the respective image signals are superimposed on the intermediate transfer member 70. Transcribed. As a result, a full-color toner image is formed on the intermediate transfer member 70.

The full-color toner image formed on the intermediate transfer member 70 reaches the secondary transfer position as the intermediate transfer member 70 rotates, and is transferred onto the recording medium by the secondary transfer device 80. The recording medium is conveyed from the paper feed tray 92 to the secondary transfer device 80 via the paper feed roller 94 and the registration roller 96. When performing the transfer operation, the secondary transfer device 8
0 is pressed by the intermediate transfer member 70 and a secondary transfer voltage is applied.

The full-color toner image transferred to the recording medium is heated and pressed by the fixing device 90 and fused to the recording medium.

The photosensitive member 20 is unitized together with the charging device 30, and this unit is attachable to and detachable from the main body of the laser beam printer 10. Further, the black developing device 52a, the magenta developing device 52b, the cyan developing device 52c, and the yellow developing device 52d can be respectively attached to and detached from the main body of the laser beam printer 10.

=== Outline of Developing Device === Next, an outline of the developing device will be described with reference to FIG. FIG. 2 is a sectional view showing the main components of the developing device. Note that, similarly to FIG. 1, in FIG. 2 as well, the up and down directions are indicated by arrows. For example, the central axis of the developing roller 510 is
It is below the central axis of the photoconductor 20. Further, in FIG. 1, the yellow developing device 52d is shown in a state of being located at the developing position facing the photoconductor 20.

The YMCK developing device 50 includes a black developing device 52a containing black (K) toner, a magenta developing device 52b containing magenta (M) toner, and
A cyan developing device 52c containing cyan (C) toner,
Also, a yellow developing device 52d containing yellow (Y) toner is provided, but since the configuration of each developing device is the same, the yellow developing device 52d will be described below.

The yellow developing device 52d includes a developing roller 510 as a developer carrier, a seal member 520, a toner storage portion 530, a frame 540, a toner supply roller 550 as a toner supply member, and a regulation blade as a layer thickness regulation member. 560, and a blade urging member 570 for urging the regulation blade.

Developing roller 510 as a toner carrier
Carries the toner T and conveys it to a developing position facing the photoconductor 20. The developing roller 510 is made of aluminum,
It is made of stainless steel, iron, etc., and is plated with nickel, chrome, etc., if necessary.
Further, the developing roller 510 can rotate about the central axis, and as shown in FIG. 2, in a direction (counterclockwise direction in FIG. 2) opposite to the rotation direction (clockwise direction in FIG. 2) of the photoconductor 20. Rotate. The central axis is below the central axis of the photoconductor 20. Further, as shown in FIG. 2, when the yellow developing device 52d faces the photoconductor 20, there is a gap between the developing roller 510 and the photoconductor 20. That is, the yellow developing device 52d develops the latent image formed on the photoconductor 20 in a non-contact state. When developing the latent image formed on the photoconductor 20,
An alternating electric field is formed between the developing roller 510 and the photoconductor 10.

The seal member 520 is the yellow developing device 5.
The toner T in 2d is prevented from leaking out of the device, and the toner T on the developing roller 510 which has passed the developing position is also prevented.
Are collected in the developing device without being scraped off. The seal member 520 is a seal made of polyethylene film or the like. The seal member 520 is a seal support metal plate 522.
Supported by the seal support sheet metal 522 and attached to the frame 540. Further, a seal urging member 524 made of maltoprene or the like is provided on the opposite side of the seal member 520 from the developing roller 510 side, and the seal member 520 is developed by the elastic force of the seal urging member 524. It is pressed against 510. The contact position where the seal member 520 contacts the developing roller 510 is above the central axis of the developing roller 510.

The toner storage portion 530 is a portion for storing the toner T, and is constituted by a part of the frame 540. The toner T stored in the toner storage portion 590
Although a stirring member may be provided to stir the developing device, in the present embodiment, each developing device (black developing device 52a, magenta developing device 52b,
Since the cyan developing device 52c and the yellow developing device 52d are rotated and the toner T in each developing device is agitated, the toner container 530 is not provided with an agitating member.

The toner supply roller 550 supplies the toner T contained in the toner container 530 to the developing roller 510. The toner supply roller 550 is made of polyurethane foam or the like, and is elastically deformed in the developing roller 5
It is in contact with 10. The toner supply roller 550 is disposed below the toner storage unit 530, and the toner T stored in the toner storage unit 530 is the toner storage unit 530.
At the lower part of the developing roller 5 by the toner supply member 530.
Supplied to 10. The toner supply roller 550 is rotatable about a central axis, and the central axis is below the central axis of rotation of the developing roller 510. Further, the toner supply roller 550 rotates in the opposite direction (clockwise in FIG. 2) to the rotation direction (counterclockwise in FIG. 2) of the developing roller 510. The toner supply roller 550 is
The developing roller 510 has a function of supplying the toner T accommodated in the toner accommodating portion 530 to the developing roller 510, and the toner remaining on the developing roller 510 after development is removed by the developing roller 51.
It also has the function of stripping from 0.

Control blade 560 as a layer thickness control member
Regulates the layer thickness of the toner T carried on the developing roller 510, and gives an electric charge to the toner T carried on the developing roller 510. This regulation blade 560 is provided with a rubber portion 5.
It has 60a and the rubber support part 560b. The rubber portion 560a is made of silicone rubber, urethane rubber, or the like,
The rubber support portion 560b is a thin plate having a spring property such as phosphor bronze and stainless steel. The rubber portion 560a is supported by the rubber supporting portion 560b, and the rubber supporting portion 560b is supported by the blade supporting sheet metal 562 with one end thereof sandwiched and supported by the pair of blade supporting sheet metal 562. Is attached to. Further, a blade backing member 570 made of malt plane or the like is provided on the opposite side of the regulation blade 560 from the developing roller 510 side.

Here, the rubber portion 560a is pressed against the developing roller 510 by the elastic force due to the bending of the rubber supporting portion 560b. Further, the blade back member 570 is
Toner is prevented from entering between the rubber supporting portion 560b and the frame 540, the elastic force due to the bending of the rubber supporting portion 560b is stabilized, and the rubber portion 560a is moved from the back of the rubber portion 560a toward the developing roller 510. By biasing the rubber portion 560a,
Is pressed against. Therefore, the blade back member 570
Improves the uniform contact of the rubber portion 560a with the developing roller 510.

The end of the regulating blade 560 opposite to the side supported by the blade supporting sheet metal 562, that is, the tip, is not in contact with the developing roller 510, and the portion apart from the tip by a predetermined distance. , Is in contact with the developing roller 510 with a certain width. That is, the regulation blade 560 is
The developing roller 510 is not in contact with the edge at the edge but is in contact with the abdomen. Further, the regulation blade 560 is arranged so that its tip end faces the upstream side in the rotation direction of the developing roller 510, and is in contact with what is called a counter.
The contact position where the regulation blade 560 contacts the developing roller 510 is below the central axis of the developing roller 510 and below the central axis of the toner supply roller 550.

The frame 540 is manufactured by joining a plurality of integrally molded frames (upper frame, lower frame, etc.) and has an opening at the bottom. The developing roller 510 is arranged in this opening with a part thereof exposed.

The yellow developing device 5 thus constructed
In 2d, the toner supply roller 550 supplies the toner T stored in the toner storage portion 590 to the developing roller 510. The toner T supplied to the developing roller 510 is
Along with the rotation of the developing roller 510, the regulation blade 560
When reaching the contact position and passing through the contact position, the layer thickness is regulated and an electric charge is applied. The toner T on the developing roller 510 whose layer thickness is regulated is
By further rotation of 0, it reaches a developing position facing the photoconductor 20 and is used for developing the latent image formed on the photoconductor 20 under an alternating electric field at the developing position. Developing roller 510
The toner T on the developing roller 510 that has passed the developing position due to the further rotation of
It is collected in the developing device without being scraped off by the seal member 520.

=== Configuration of Toner === Next, the configuration of the toner T according to the present embodiment will be described. The toner T has mother particles and an external additive. The mother particles and the external additive are a Henschel mixer,
They are mutually dry-mixed and adhered to each other by a high-speed fluidized mixer such as Perpenmeier or a mixer such as mechanochemical method. The toner T may be either negative polarity or positive polarity toner.

The mother particles have materials such as a colorant, a charge control agent, a release agent (WAX), and a resin. Using these materials, known kneading and pulverizing method, spray-drying method,
And the mother particles are produced by a polymerization method or the like. The mother particles may further contain a dispersant, a magnetic material, other additives and the like.

As the mother particles, polystyrene and copolymers such as hydrogenated styrene resin, styrene / isobutylene copolymer, ABS resin, ASA resin, AS resin, A
AS resin, ACS resin, AES resin, styrene / P-chlorostyrene copolymer, styrene / propylene copolymer,
Styrene / butadiene crosslinked polymer, styrene / butadiene / chlorinated paraffin copolymer, styrene / allyl /
Alcohol copolymer, styrene / butadiene rubber emulsion, styrene / maleic acid ester copolymer, styrene / isobutylene copolymer, styrene / maleic anhydride copolymer, acrylate resin or methacrylate resin and its copolymer, Styrene / acrylic resin and its copolymer, for example, styrene / acrylic copolymer, styrene / diethylamino / ethylmethacrylate copolymer, styrene / butadiene / acrylic acid ester copolymer, styrene / methylmethacrylate copolymer , Styrene / n-butyl methacrylate copolymer, styrene / methyl methacrylate / n-butyl acrylate copolymer, styrene / methyl methacrylate / butyl arylate / N- (ethoxymethyl) acrylamide copolymer Styrene / glycidyl methacrylate copolymer, styrene / butadiene / dimethyl / aminoethyl methacrylate copolymer, styrene / acrylic acid ester / maleic acid ester copolymer, styrene / methyl methacrylate / 2-ethylhexyl acrylate copolymer Coal, styrene / n-butyl arylate / ethyl glycol methacrylate copolymer, styrene / n-
Butylmethacrylate / acrylic acid copolymer, styrene / n-butylmethacrylate / maleic anhydride copolymer, styrene / butylacrylate / isobutylmaleic acid half ester / divinylbenzene copolymer, polyester and its copolymer, Polyethylene and its copolymer, epoxy resin, silicone resin, polypropylene and its copolymer, fluororesin, polyamide resin, polyvinyl alcohol resin, polyurethane resin, polyvinyl butyral resin, etc., one kind or a blend of two or more kinds. Can be used.

Examples of the colorant include carbon black, spirit black, nigrosine, rhodamine, triaminotriphenylmethane, cationic, dioxazine, copper phthalocyanine, berylylene, azo, gold-containing azo pigment, azochrome complex, carmine, Benzidine,
Solar Pure Yellow 8G, quinacridone, polytungstophosphoric acid, induslen blue, sulfonamide derivative and the like can be used.

As the charge control agent, an electron-accepting organic complex, chlorinated polyester, nitrofunnic acid, quaternary ammonium salt, pyridinyl salt and the like can be used.

As the release agent (WAX), paraffin wax such as low molecular weight polypropylene, low molecular weight polyethylene, ethylene bisamide, microcrystalline wax, carnauba wax, beeswax, etc. is preferably used. It is not particularly limited as long as it is incompatible and has a releasing property. In the present embodiment, “not compatible” means a state in which the wax is dispersed in the mother particles in an island shape and is not incorporated in the molecular chain of the resin when melt-kneaded.

Note that oil may be applied to the fixing roller in order to prevent the toner T from adhering to the fixing roller during the fixing process, but in the present embodiment, such oil application is unnecessary. Therefore, a large amount of release agent is included in the mother particles. The content of the release agent is 3 to 10% by weight based on the resin.

As the dispersant, metal soap, polyethylene glycol or the like can be used. Other additives include
Zinc stearate, zinc oxide, cerium oxide and the like can be used.

As the magnetic agent, Fe, Co, Ni, C
Metal powder such as r, Mn, Zn, Fe_ThreeO _Four, Fe_TwoO_Three,
Cr_TwoO_Three, Metal oxides such as ferrite, manganese and acid
For alloys that show ferromagnetism by heat treatment of alloys containing
It is possible to pre-treat the coupling agent etc. in advance.
It doesn't matter.

As the external additive, various kinds of external additives having a hydrophobic treatment can be used. In the toner T according to the present embodiment, silica is used as the external additive, but in addition to silica, fine particles of metal oxides such as aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, and chromium oxide, Fine particles of nitride such as silicon nitride,
Fine particles of a carbide such as silicon carbide, fine particles of a metal salt such as calcium sulfate, barium sulfate, calcium carbonate and the like, inorganic fine particles such as a composite thereof, and organic fine particles such as acrylic fine particles can be used. As the surface treatment agent, a silane coupling agent, a titanate coupling agent, a fluorine-containing silane coupling agent, a silicone oil, or the like can be used. The hydrophobicity of the external additive treated with these treating agents is preferably 60% or more according to the conventional methanol method. When it is less than this range, adsorption of water tends to cause deterioration of chargeability and fluidity at high temperature and high humidity, which is not preferable. The particle size of the external additive is 0.001 to 1 μ from the viewpoint of transportability and chargeability.
It is preferably m. Further, the external additive is not limited to one kind, and a mixture of two or more kinds can be used.

=== Toner Analysis Method === Next, a toner analysis method will be described with reference to FIG. FIG. 3 shows the toner according to the present embodiment.
FIG. 6 is a diagram for explaining a toner analysis method used for analyzing the adhesion state of mother particles and external additive particles. FIG. 4 is a diagram showing true spherical particles made only of the element C contained in the mother particles and true spherical particles made only of the element Si contained in the external additive particles. FIG. 5 is an equivalent particle size distribution chart of the toner particles according to the present embodiment.

The toner analysis method according to the present embodiment can also analyze toner particles having a particle size of 1 micron or less, unlike the above-described small hole passage method. Furthermore, the above-mentioned scanning electron microscope (SEM: Scanning Electron)
Unlike Microscope), the physical properties of each toner particle can be quantitatively analyzed. In these respects, it is an extremely excellent toner analysis method.

In the present embodiment, as a method for analyzing the adhesion state between the mother particles of the toner T and the external additive particles, the Electrophotographic Society of Japan Annual Meeting (total 95 times), "Japan H.
ardcopy '97 ”,“ New external evaluation method-Toner analysis by particle analyzer- ”, Toshiyuki Suzuki, Toshio Takahara, The Electrophotographic Society of Japan, July 9, 1997.
The toner analysis method disclosed in Jpn. The particle analyzer may be, for example, PT1000 manufactured by Yokogawa Electric.

In this toner analysis method, particles of toner T formed by adhering external additive particles made of silica or the like and containing element Si to mother particles made of resin or the like and containing element C are introduced into plasma. By doing so, the particles of the toner T are excited, and the elemental analysis is performed by obtaining the emission spectrum as shown in FIG. 3 accompanying the excitation. Figure 3
In, the horizontal axis of the emission spectrum indicates the time axis.

First, as shown in FIG. 3A, when the particles of the toner T in which the external additive particles are attached to the mother particles of the toner T are introduced into the plasma, the element C contained in the mother particles and the outside The element Si contained in the additive particles emits light together.

At this time, since the mother particles and the external additive particles are simultaneously introduced into the plasma, the element C contained in the mother particles and the element Si contained in the external additive particles emit light at the same time. In this way, when the element C contained in the mother particle and the element Si contained in the external additive particle emit light at the same time, the mother particle and the external additive particle are said to be synchronized.
In other words, the state in which the mother particles and the external additive particles are synchronized is
This means that the external additive particles are attached to the mother particles.

When mother particles to which the external additive particles are not attached or external additive particles separated from the mother particles are introduced into the plasma as shown in FIG. Both the element C contained in the mother particles and the element Si contained in the external additive particles emit light, but at this time, since the mother particles and the external additive particles are introduced into the plasma at different times,
Element C contained in the mother particles and element S contained in the external additive particles
Light is emitted at a time different from i (for example, when the mother particles are introduced into the plasma before the external additive particles, the element C contained in the mother particles emits light first, and after that, the external additive is delayed). The element Si contained in the particles emits light).

As described above, when the mother particles and the external additive particles emit light at different times, it is said that the mother particles and the external additive particles are not synchronized (that is, asynchronous). In other words, the state where the mother particles and the external additive particles are asynchronous is a state in which the external additive particles are not attached to the mother particles,
It exists as free external additive particles.

Further, in FIG. 3, the height of the light emission signal represents the intensity of the light emission, but the intensity of the light emission is not the size or shape of the particle, but the element contained in the particle ( It is proportional to the number of C, Si) atoms.

Then, when the light emission of the element C contained in the mother particles and the element Si contained in the external additive particles is obtained, as shown in FIG.
As shown in, in order to express the emission intensity of each element as the size of the particle, the particle size is determined according to the emission intensity of the element C,
Assuming a true spherical particle made only of the element C contained in the mother particle and a true spherical particle made of only the element Si contained in the external additive particle having a particle size according to the emission intensity of the element Si. To do.

A true spherical particle made of only the element C contained in the mother particle, which has a particle diameter corresponding to the emission intensity of the element C, is called an equivalent particle of the mother particle, and its particle diameter (diameter )
Is called the equivalent particle size of the mother particles. Further, the element Si contained in the external additive particles having a particle diameter according to the emission intensity of the element Si.
The spherical particles formed only by the above are called the equivalent particles of the external additive particles, and the particle diameter (diameter) is called the equivalent particle diameter of the external additive particles.
Since the external additive particles are very small, they cannot be detected one by one. Therefore, the emission signals of the detected external additive particles are added together and converted into one equivalent particle for analysis. .

The cube root voltage is used to indicate the size of the equivalent particle size. The light emission intensity for a certain element is detected as a voltage value. Since this voltage is proportional to the number of atoms (mass), the cube root of the voltage value is taken to indicate the particle size, and at this cube root voltage, It was decided to indicate the size of the equivalent particle size.

With respect to the toner according to the present embodiment, the cube root voltage value obtained in accordance with each emission intensity of the element C contained in the mother particles and the element Si contained in the external additive particles is calculated as follows. When plotted for each particle, an equivalent particle size distribution diagram of toner particles as shown in FIG. 5 is obtained. In FIG.
The horizontal axis (X axis) represents the cube root voltage of the equivalent particles of the mother particles, and the vertical axis (Y axis) represents the cube root voltage of the equivalent particles of the external additive particles.

The toner particles on the horizontal axis (X axis) represent toner particles composed of non-synchronized mother particles to which external additive particles are not attached, and the toner particles on the vertical axis (Y axis) are the mother particles. Asynchronous external additive particles released from particles (free external additive particles)
Represents toner particles consisting of. Further, the toner particles not on the horizontal axis and the vertical axis represent synchronous toner particles in which the external additive particles are attached to the mother particles. Details of the equivalent particle size distribution chart of the toner shown in FIG. 5 will be described later.

According to such a toner analysis method, the adhesion state of the external additive particles in each toner particle, the number of mother particles to which the external additive particles are not adhered, the number of free external additive particles,
Various matters such as the number of mother particles to which the external additive particles are attached can be accurately analyzed.

In the above example, the toner analysis method disclosed in the above-mentioned dissertation collection is used as a method for analyzing the adhesion state between the mother particles of the toner and the external additive particles. Any toner analysis method can be used as long as it is a toner analysis method that can analyze the adhesion state of the mother particles and the external additive particles.

=== Details of Toner According to the Present Embodiment =
== Next, with reference to FIG. 5 described above, details of the toner according to the present exemplary embodiment (hereinafter, also referred to as “the present toner”) will be described in comparison with a reference toner.

<<< Differences in Configuration between the Present Toner and the Reference Toner >>>> The equivalent particle size distribution chart of the present toner is shown in FIG.
The toner particles on the horizontal axis (X axis) are as shown in
The toner particles are composed of asynchronous mother particles to which external additive particles are not attached. In addition, this equivalent particle diameter distribution chart is a distribution chart including particles having a particle diameter of 1 μm or less,
Therefore, the equivalent particle size distribution of the entire toner particles including the small particle size toner is accurately shown.

Here, as the present toner, when analyzed by the above-described toner analysis method, the number of mother particles to which the external additive particles are not attached, that is, the number of particles on the horizontal axis (X axis) in FIG. The number is the total number of toner mother particles,
That is, the number is 15% or less of the number of particles not on the vertical axis (Y axis) in FIG. 5, and the ratio of the asynchronous mother particles to the entire mother particles (synchronous mother particles and asynchronous mother particles) is small. To use. In addition, the number of the mother particles to which the external additive particles are not attached is 5% of the total number of the mother particles of the toner, and this toner is referred to as the present toner 1. But 10% of the total number of toner mother particles
And the number of mother particles to which external additive particles are not attached is 1 of the total number of mother particles of the toner.
The toner of 5% was designated as Toner 3 of the present case.

On the other hand, as the reference toner, when analyzed by the above-described toner analysis method, the number of mother particles to which the external additive particles are not attached exceeds 15% of the total number of the mother particles of the toner. Use one. The number of the mother particles to which the external additive particles are not attached is 20% of the total number of the mother particles of the toner, which is referred to as Reference Toner 1, and the number of the mother particles to which the external additive particles are not attached. Was 25% of the total number of the mother particles of the toner, which was used as the reference toner 2.

The toner of the present invention can be manufactured by various methods. For example, it can be manufactured by a method in which a large amount of an external additive is added to a toner composed of toner particles having a small particle diameter, and then this toner is mixed with another toner.

<<< Differences in Operation between Toner of the Present Case and Reference Toner >>>> Next, when the developing device is actually operated using the toner of the present case and the reference toner having the above-mentioned structural differences, What kind of difference in operation occurs will be described with reference to FIG. FIG. 6 is a diagram for explaining a difference in operation between the present toner and the reference toner.

First, the reference toner 1 is filled with the toner containing portion 590.
I put it in. Next, when the toner supply roller 550 and the developing roller 510 are rotated, the reference toner 1 accommodated in the toner accommodating portion 590 is supplied to the developing roller 510, and the regulating blade 560 is further rotated as the developing roller 510 further rotates. The layer thickness is regulated by the toner, the toner reaches the developing position facing the photoconductor 20, and then is returned to the toner containing portion 590.
It was peeled off from No. 10 and supplied to the developing roller 510.

However, when the developing roller 510 was rotated several times, whitish particles adhered to the surface of the developing roller 510. Further, as the developing roller 510 continued to rotate, toner (hereinafter, also referred to as “conveyance streak”) adhering to the developing roller 510 in the form of streaks appeared along the circumferential direction of the developing roller 510. Further, when the developing roller 510 continues to rotate, the stripe-shaped toner becomes noticeable, and when 1000 sheets of A4 size printing paper are printed, the stripe-shaped toner is generated.
The toner was scattered on contact with 0, and the developing device was soiled. In addition, a so-called filming phenomenon occurs in which the toner is fused to the developing roller 510.

Then, when the toner on the developing roller 510 was removed by suction, whiteish particles were strongly adhered to the surface of the developing roller 510. Analysis of the whitish particles revealed that the toner particles had a particle size of about 1 μm, contained a large amount of a release agent (WAX), and had a small amount of external additives attached. It should be noted that the reason why the appearance was white is because the release agent (WAX) itself is white.

The whitish toner particles contain a large amount of a release agent (WAX) and have little adhesion of external additives, and thus have high tackiness. Therefore, once attached to the developing roller 510, the toner supplying roller 550 does not remove the toner from the developing roller 510 and leaves it on the developing roller 510. Therefore, the toner supply roller 550 will supply the toner onto the remaining whitish particles. The toner supplied onto the remaining whitish particles is difficult to contact the surface of the developing roller 510, so that even if the toner passes through the regulation blade 560, sufficient charge is not imparted, and the layer thickness is not regulated properly. As a result, as described above, the toner adhered in the form of stripes appears along the circumferential direction of the developing roller 510.

Next, the reference toner 2 is added to the toner containing portion 590.
I put it in. When the developing roller 510 was rotated several times, whitish particles adhered to the surface of the developing roller 510. Further, when the developing roller 510 continues to rotate, the developing roller 5
A large number of transport stripes appeared along the circumferential direction of 10. further,
When the developing roller 510 continues to rotate, streak-shaped toner becomes noticeable, and the streak-shaped toner comes into contact with the seal member 520 and scatters the toner before the printing is performed on the printing paper, thus contaminating the developing device. In addition, the toner leaked out of the developing device. At this time, the filming phenomenon described above also occurred.

Next, the toner 1 of the present case is stored in the toner containing portion 590.
I put it in. Next, when the toner supply roller 550 and the developing roller 510 are rotated, the subject toner accommodated in the toner accommodating portion 590 is supplied to the developing roller 510,
With further rotation of the developing roller 510, the layer thickness is regulated by the regulating blade 560 to reach the developing position facing the photoconductor 20 and then returned to the toner accommodating portion 590, and the developing roller 51 is fed by the toner supplying roller 550.
It was stripped from 0 and supplied to the developing roller 510.

When Toner 1 of the present case is used, the developing roller 510 continues to rotate, and the A4 size printing paper is used for 200 times.
Even after printing 00 sheets, whiteish particles did not appear on the surface of the developing roller 510, and as a result, the above-described transport streak, toner scattering phenomenon, and filming phenomenon did not occur.

Next, the toner 2 of the present case is stored in the toner containing portion 590.
I put it in. Even when the toner 2 of the present case is used, even when the developing roller 510 continues to rotate and 20,000 sheets of A4 size printing paper are printed, white particles do not appear on the surface of the developing roller 510. As described above, neither the conveyance streak, the toner scattering phenomenon, nor the filming phenomenon occurred.

Next, the toner 3 of the present case is stored in the toner containing portion 590.
I put it in. In the case of using the toner 3 of the present case, when the developing roller 510 continued to rotate and 10000 sheets of A4 size printing paper were printed, the above-described filming phenomenon occurred.
Even after printing 00 sheets, the conveyance stripes and the toner scattering phenomenon did not occur. In addition, 10 sheets of A4 size printing paper
The fact that the above-described filming phenomenon occurs after printing 000 sheets is not a practical problem.

In the toner 1, the toner 2, and the toner 3 of the present invention, as described above, in the toner of the present invention, the number of the mother particles to which the external additive particles are not attached is the mother particle of the toner. 15% or less of the total number of particles,
The ratio of the asynchronous mother particles to the entire mother particles (synchronous mother particles and asynchronous mother particles) is small.

Therefore, it is possible to prevent a phenomenon in which toner particles having a high adhesiveness due to containing a large amount of a release agent (WAX) and little adhesion of an external additive remain on the developing roller 510. It

=== Other Embodiments === The developing device and the like according to the present invention have been described above based on some embodiments. However, the above-described embodiments of the present invention will not be construed as an understanding of the present invention. It is for the purpose of facilitation and does not limit the present invention. The present invention can be modified and improved without departing from the spirit of the present invention, and it goes without saying that the present invention includes equivalents thereof.

The present invention can be applied to any developing device and the like as long as it can prevent the toner particles from strongly adhering to the toner carrier.

For example, the present invention is particularly effective for a toner having a release agent (WAX) because the release agent (WAX) itself has high adhesiveness, but the release agent (WAX) has a high release property. The present invention can also be applied to non-toner.

Further, according to the present invention, the tip of the above-mentioned regulating blade does not contact the toner carrier, and the portion apart from the tip by a predetermined distance contacts the toner carrier, and the contact position thereof. Is particularly effective for a developing device whose position is below the rotation center position of the toner carrier, but the developing device in which the tip of the regulating blade is in contact with the toner carrier, or the contact position is the toner carrier. It is also applicable to a developing device located above the rotation center position of the holding body.

Further, the present invention has a rotatable toner supply member for supplying toner particles to the toner carrier, and the rotation direction of this toner supply member is opposite to the rotation direction of the toner carrier. However, it is also applicable to a developing device in which the rotation direction of the toner supply member is the same as the rotation direction of the toner carrier.

Further, according to the present invention, there is provided a seal member which is in contact with the toner carrier for preventing the leakage of the toner in the developing device, and the contact position is the rotation of the toner carrier. This is particularly effective for the developing device located above the center position, but is also applicable to the developing device where the contact position is below the rotation center position of the toner carrier.

Further, according to the present invention, there is provided a toner accommodating portion for accommodating toner, the toner supply member is disposed below the toner accommodating portion, and the toner accommodated in the toner accommodating portion is the toner. It is particularly effective for a developing device in which the toner carrier is supplied to the toner carrier by the toner supply member in the lower part of the storage part, but the toner supply member is arranged in the upper part of the toner storage part. It is also applicable to the developing device in which the toner accommodated in the toner container is supplied to the toner carrier by the toner supply member above the toner container.

Furthermore, in the above-described embodiment,
Although an intermediate transfer type full-color laser beam printer has been described as an example of the image forming apparatus, the present invention is applicable to various image forming apparatuses such as a full-color laser beam printer other than the intermediate transfer type, a monochrome laser beam printer, a copying machine, a facsimile, and the like. Applicable.

Further, the photosensitive member is not limited to a so-called photosensitive roller constituted by providing a photosensitive layer on the outer peripheral surface of a cylindrical conductive substrate, and a photosensitive layer is provided on the surface of a belt-shaped conductive substrate. A so-called photosensitive belt configured as described above may be used.

Further, the developing device according to the present invention is not limited to the device having the structure described in the above-mentioned embodiment, and at least the toner having the mother particles and the external additive particles, and this toner are It is possible to apply to any developing device as long as it is a developing device that has a toner carrier that carries and moves, and that develops a latent image carried on the image carrier.

For example, as the toner carrier, any of magnetic, non-magnetic, conductive, insulating, metal, rubber, resin and the like can be used as long as it can constitute the toner carrier. For example, in terms of materials, metals such as aluminum, nickel, stainless steel, iron, natural rubber, silicon rubber, urethane rubber, butadiene rubber, chloroprene rubber, neoprene rubber, rubbers such as NBR, styrene resin, vinyl chloride resin, polyurethane resin Resins such as polyethylene resin, methacrylic resin, and nylon resin can be used. It goes without saying that the upper layer of these materials can be coated and used. In that case, as the coating material, polyethylene, polystyrene, polyurethane, polyester, nylon, acrylic or the like can be used. Further, as for the form, all of non-elastic body, elastic body, single layer, multi-layer, film, roller and the like can be used.

The same applies to the toner supply member, and as the material, in addition to the polyurethane foam described above, polystyrene foam, polyethylene foam, polyester foam, ethylene propylene foam, nylon foam, silicone foam and the like can be used. . The foam cells of the toner supply means may be either single cells or open cells. The material is not limited to the foam material, and a rubber material having elasticity may be used. For more information,
Silicone rubber, urethane rubber, natural rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, butyl rubber, ethylene propylene rubber, epichlorohydrin rubber, nitrile butadiene rubber, acrylic rubber with conductive agents such as carbon dispersed and molded Can be used.

As the layer thickness regulating member, a member having a rubber portion and a rubber supporting portion is used as described above. The material of the rubber portion is natural rubber in addition to the silicone rubber and urethane rubber described above. Carbon can be used for isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, butyl rubber, ethylene propylene rubber, epichlorohydrin rubber, nitrile butadiene rubber, acrylic rubber. Further, the rubber supporting portion and the rubber portion may not be separately manufactured and then joined to each other. For example, a material obtained by integrally molding these materials alone or a stainless thin plate alone having a layer thickness What constituted the control member can be used similarly. Further, it can be used by coating the upper layer portion of the above-mentioned material with a resin. As the coating material,
Polyethylene, polystyrene, nylon, polyurethane, polyester, etc. can be used.

Further, the developing device according to the above-mentioned embodiment,
A computer system including a computer main body, a display device such as a CRT, and an input device such as a mouse and a keyboard can also be realized, and the computer system realized in this way is superior to the conventional system as a whole system. Becomes

[0121]

According to the present invention, it is possible to realize a developing device, an image forming device, a toner, and a computer system for forming a high quality image by using a toner containing toner particles having a small particle diameter. Is possible.

[Brief description of drawings]

FIG. 1 is a diagram showing main components constituting a laser beam printer 10.

FIG. 2 is a cross-sectional view showing main components of the developing device.

FIG. 3 is a diagram for explaining a toner analysis method used for analyzing a state of adhesion between mother particles and an external additive regarding the toner according to the present embodiment.

FIG. 4 is a diagram showing a true spherical particle made only of element C contained in a mother particle and a true spherical particle made only of element Si contained in an external additive.

FIG. 5 is an equivalent particle size distribution diagram of toner particles according to the present exemplary embodiment.

FIG. 6 is a diagram for explaining a difference in operation between the present toner and the reference toner.

FIG. 7 is a diagram for explaining the principle of the small hole passage method.

[Explanation of symbols]

10 ... Laser beam printer 20 ... Photoreceptor 30 ... Charging device 40 ... Exposure device 50 ... YMCK developing device 52a ... Black developing device 52b ... Magenta developing device 52c ... Cyan developing device 52d ... Yellow developing device 60 ... Primary transfer device 70 ... Intermediate transfer member 80 ... Secondary transfer device 90 ... Fixing device 92 ... Paper feed tray 94 ... Paper feed roller 96 ... Register roller 510 ... Developing roller 520 ... Sealing member 522 ... Seal support sheet metal 524 ... Seal biasing member 530 ... Toner storage unit 540 ... Frame 550 ... Toner supply roller 560 ... Regulation blade 560a ... rubber part 560b ... rubber support 562 ... Blade support sheet metal 570 ... Blade urging member T ... Toner

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/08 501 G03G 15/08 501Z 504A 504 505A 505 507L 507 9/08 381

Claims (13)

[Claims] 1. A toner having mother particles and external additive particles,
In a developing device that has a toner carrier that carries and moves this toner, and that develops a latent image carried on the image carrier, the number of mother particles to which external additive particles are not attached is The developing device is characterized in that it is 15% or less of the total number of the mother particles of the toner. 2. The developing device according to claim 1, wherein the mother particles have a release agent. 3. The developing device according to claim 2, wherein the release agent has incompatibility with the mother particles. 4. The developing device according to claim 3, wherein the mother particles are manufactured by a pulverization method. 5. The developing device according to claim 1, wherein the tip of the layer thickness regulating member is not in contact with the toner carrier and is apart from the tip by a predetermined distance. A developing device, wherein a portion is in contact with the toner carrier, and the contact position is below the rotation center position of the toner carrier. 6. The developing device according to claim 1, further comprising a rotatable toner supply member that supplies toner to the toner carrier, and the rotation direction of the toner supply member is A developing device, which is in a direction opposite to a rotating direction of the toner carrier. 7. The developing device according to claim 1, further comprising a seal member that is in contact with the toner carrier to prevent toner leakage in the developing device. The developing device is characterized in that the abutting position is above the rotation center position of the toner carrier. 8. The developing device according to claim 6, further comprising: a toner storage portion that stores toner, wherein the toner supply member is disposed below the toner storage portion and is stored in the toner storage portion. The developing device is characterized in that the toner is supplied to the toner carrier by the toner supply member below the toner storage portion. 9. A toner having mother particles and external additive particles,
In a developing device that has a toner carrier that carries and moves this toner, and that develops a latent image carried on the image carrier, the number of mother particles to which external additive particles are not attached is 15% or less of the total number of mother particles of the toner, the mother particles have a release agent that is incompatible with the mother particles, the mother particles are manufactured by a pulverization method, The tip of the layer thickness regulating member is not in contact with the toner carrier, and the portion apart from the tip by a predetermined distance is in contact with the toner carrier, and the contact position is the toner carrier. It has a rotatable toner supply member which is below the rotation center position of the carrier and supplies toner to the toner carrier, and the rotation direction of the toner supply member is the same as the rotation direction of the toner carrier. Is in the opposite direction to prevent the toner from leaking in the developing device. The toner carrier has a seal member that is in contact with the toner carrier, the contact position is higher than the rotation center position of the toner carrier, and the toner container has a toner container that stores the toner. A supply member is disposed below the toner storage unit, and the toner stored in the toner storage unit is supplied to the toner carrier by the toner supply member below the toner storage unit. Developing device. 10. A developing device having a toner having mother particles and external additive particles, and a toner carrier that carries and moves the toner, and develops a latent image carried by the image carrier. In the image forming apparatus including the above, the number of mother particles to which external additive particles are not attached is 15% or less of the total number of mother particles of the toner. 11. An image forming apparatus comprising the developing device according to claim 2. 12. A toner carrier, which carries and moves toner, is used in a developing device for developing a latent image carried by an image carrier, and has mother particles and external additive particles. In the toner, the number of mother particles to which external additive particles are not attached is 15% or less of the total number of mother particles of the toner. 13. An image carrier having a computer main body, a display device, an input device, a toner having mother particles and external additive particles, and a toner carrier for carrying the toner and moving the toner. In a computer system including an image forming apparatus including a developing device that develops a carried latent image, the number of mother particles to which external additive particles are not attached is 15 times the total number of mother particles of the toner. % Or less, a computer system characterized by being below.