JP2002236390A - Toner and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress the filming of toner on a toner contact member by sticking an external additive to fine base particles as uniform as possible. SOLUTION: As for the toner T, the isolation ratio of the base particle is set to be <=15%, and the roundness of the fine base particle whose particle diameter is 1.5 to 2.5 μm is set to be 0.85 to 0.95. Then, the melt-sticking of the free base particle 18' to the toner contact member such as a latent image carrier, a toner carrier and a toner control member, is reduced, and also, the external additive 19 more uniformly sticks to the fine base particle 18 too, then, the melt-sticking of the fine base particle 18 to the toner contact member is also effectively reduced. Then, the filming on the toner contact member is effectively suppressed. Then, the durability of the toner contact member such as the latent image carrier, the toner carrier and the toner control member, is improved, and also, the good image quality is maintained for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the technical field of toner for developing an electrostatic latent image on a latent image carrier, comprising a large number of base particles and a large number of particles of an external additive such as silica. It belongs to the technical field of an image forming apparatus that forms an image using this toner, and in particular, suppresses toner filming to a toner contact member that comes into contact with the toner, such as a latent image carrier, a toner carrier, and a toner regulating member. In addition, the present invention belongs to the technical field of a toner capable of favorably performing low-temperature fixing and an image forming apparatus using the toner.

[0002]

2. Description of the Related Art In an image forming apparatus using toner, an electrostatic latent image on a latent image carrier is developed with toner, and the developed image is transferred to a transfer material such as paper. Then, a transferred image of the exposed electrostatic latent image is formed on the latent image carrier, and then the transferred image is fixed to form an image.

[0003]

2. Description of the Related Art As an example of such a conventional image forming apparatus, there is a full-color intermediate transfer type image forming apparatus as shown in FIG. In the image forming apparatus 1, an image is exposed as an electrostatic latent image on a photoconductor 2 as a latent image carrier, and the electrostatic latent image on the photoconductor 2 is yellow,
The magenta, cyan, and black non-magnetic one-component developing units 3, 4, 5, and 6 are sequentially developed (the order of each color is arbitrary) to be visualized. After the color transfer is performed on the intermediate transfer belt 7a of the transfer body 7 and the primary transfer is performed, the color is secondarily transferred to a transfer material 9 such as paper on a secondary transfer roller 8a of a transfer device 8, and then heated by a fixing device 10. By fixing, a desired image can be obtained on the transfer material 9.

Each of the non-magnetic one-component developing units 3, 4, 5, and 6 has substantially the same configuration, and is a contact developing type developing unit in which the conductive developing roller 16 and the photosensitive member 2 are in contact with each other. As shown in FIG. 2A, each of the developing devices 3, 4, 5, and 6 transfers the toner T in the toner storage unit 13 to the toner conveying unit 1.
At 4, the toner T is conveyed to a toner supply roller 15 serving as a toner supply unit, and the toner T is supplied to the developing roller 16 by the toner supply roller 15 and carried on the surface of the developing roller 16. When the developing voltage of the AC bias is applied to the developing roller 16 and the developing roller 16 is rotated at a high speed, the toner T on the developing roller 16 is a toner regulating member pressed against the surface of the developing roller 16. The toner is regulated to a uniform thin layer by a certain toner regulating blade 17 and is uniformly charged. Then, the developing roller 1
The toner T on 6 is uniformly conveyed toward the photoconductor 2 that is in contact with the developing roller 16. Then, the toner T on the developing roller 16 is applied with the developing voltage applied to the developing roller 16.
Are moved toward the photoconductor 2, the electrostatic latent image on the photoconductor 2 is developed with the toner T.

A non-magnetic one-component developing method using the conductive developing roller 16 includes a non-contact developing method in which the developing roller 16 and the photosensitive member 2 are separated from each other. In the non-contact developing method, a developing voltage is applied to the developing roller 16, and the toner T particles on the developing roller 16 are applied to the photosensitive member 2 by the developing voltage.
The electrostatic latent image on the photoreceptor 2 is jumped and developed with the toner T by the jumping movement toward.

[0006] Such a conventional non-magnetic one-component developing apparatus 1
In this case, the toner T may be fused on a toner contact member such as the developing roller 16, the toner regulating blade 17, and the photoconductor 2 which comes into contact with the toner to cause filming. For this reason, poor conveyance of the toner T by the developing roller 16, poor regulation of the toner regulating blade 17, poor development of the photoconductor 2, and the like occur, and image quality deteriorates. Therefore, conventionally, as shown in FIG. 2B, an external additive 19 such as silica is coated on the base particles 18 made of the resin of the toner T to prevent the toner T from adhering to the above-mentioned toner contact member. I have. The diameter of the external additive 19 is set to be extremely smaller than the diameter of the base particles 18. Further, in the heat fixing by the fixing device 10, in order to enable low-temperature fixing, conventionally, the toner T uses the base particles 18 having a relatively soft and low softening point even at normal temperature.

[0007]

By the way, the toner T described above is prepared by mixing the base particles 18 and particles of the external additive 19 (hereinafter, also simply referred to as the external additive 19) so that the external additive is added to the base particles 18. Although the base particles 18 and the external additives 19 are actually adhered to each other as shown in FIG. 2B (reference numeral 18 denotes the base particles themselves and the external additives in the same manner as described above). No. 19 is used for both the external additive itself and the external additive adhered to the base particles, as described above, and no external additive 19 is attached. The free base particles 18 'and the free external additives 19' not attached to the base particles 18 are mixed.

However, in general, a large number of particles having various particle diameters of about 1.5 μm or more are mixed in the base particles 18, and the smaller the particle diameter, the lower the circularity of the base particles 18. This is due, etc. manufacturing problem of the toner T in the pulverization method. When the circularity of the base particles 18 is reduced as described above, not only a portion (for example, a sharp portion) where the external additive 19 hardly adheres to the base particles 18, but also a small portion is formed in a concave portion of the base particles 18. External additive 19 enters,
The effect of the external additive 19 cannot be sufficiently obtained.

When the amount of the free base particles 18 ′ increases in the toner T, not only the free base particles 18 ′ easily adhere to the toner contact member, but also the external additive 1
Since the amount of adhesion of 9 is lowered, the mother particle 18 is not a free base particles 18 'also tends to adhere to the toner contact member. Base particle 1
When 8 adheres to the toner contact member, filming occurs on the toner contact member, and the durability of the toner contact member is reduced. In particular, in the base particles 18 having a low softening point, the base particles 18 are relatively soft, so that the base particles 18 are easily attached to the toner contact member, and filming easily occurs on the toner contact member. In addition, since the base particles 18 attached to the toner contact member are harder to remove than the base particles 18 of the fine particles, filming is more likely to occur on the toner contact member.

The present invention has been made in view of such a problem, and an object of the present invention is to make it possible for an external additive to adhere as uniformly as possible to mother particles of fine particles so that a toner carrier and a toner An object of the present invention is to provide a toner capable of more effectively suppressing filming on a toner contact member such as a regulating member and a latent image carrier, and an image forming apparatus using the toner.

[0011]

According to a first aspect of the present invention, there is provided a toner having at least a large number of base particles and a large number of particles of an external additive. The free base particles to which no free base particles are adhered have a base particle release rate of 15% or less, and among the base particles, the circularity of the base particles of fine particles having a particle size of 1.5 to 2.5 μm is 0.5%. It is characterized in that it is set to 85 to 0.95. The toner according to claim 1, wherein the external additive is silica.

Further, according to the image forming apparatus of the present invention,
A latent image carrier on which an electrostatic latent image is formed, and a toner carrier that transports toner to develop an electrostatic latent image on the latent image carrier;
And a developing device having a toner regulating member for regulating at least the toner conveyed toward the latent image carrier by the toner carrier, wherein the toner is the toner according to claim 1. .

[0013]

In the toner of the present invention thus constituted, the base particle release rate is set to 15% or less, and the circularity of the base particles of fine particles having a particle size of 1.5 to 2.5 μm is 0.5. 8
It is set to 5 to 0.95. Thereby, in a toner having a base particle release rate of 15% or less, the circularity of the base particles of the fine particles is set to a higher appropriate value, and thus the free base particles are separated from the latent image carrier, the toner carrier, and Fusing to the toner contact member such as the toner regulating member is reduced, and the external additive is more uniformly attached to the base particles of the fine particles, so that the base particles of the fine particles adhere to the toner contact member. Fusion is also effectively reduced. Thereby, filming of the toner contact member is effectively suppressed. Therefore, the toner of the present invention improves the durability of the toner contact member such as the latent image carrier, the toner carrier, and the toner regulating member, and improves the image quality over a long period of time.

In particular, in the toner of the second aspect of the present invention, silica is used as an external additive, and the amount of silica adhering to the base particles is an appropriate amount. The toner of the present invention prevents filming on the toner contact member because the base particles are coated with a predetermined amount of silica so that the surface of the low melting point base particles is not excessively exposed. While improving the low-temperature fixability.

On the other hand, in the image forming apparatus of the present invention,
By using the toner, the durability of the toner contact member such as the latent image carrier, the toner carrier, and the toner regulating member is improved, and good image quality can be obtained. In addition, since the surface of the base particles having a low melting point is hardly exposed,
The image forming apparatus of the present invention has good low-temperature fixability while preventing filming of the toner contact member.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. An image forming apparatus according to an embodiment of the present invention has the same configuration as the image forming apparatus 1 shown in FIGS. 1 and 2A, respectively. Therefore, the operation of the image forming apparatus 1 of this example at the time of image formation is the same as that of the above-described conventional example.

Further, the toner T of the present invention used in the image forming apparatus 1 of this embodiment comprises at least a large number of base particles 18 and a large number of external additives 19 such as silica.
The base particles 18 are made of a resin having a low softening point that is soft at room temperature,
It contains at least 1.5-2.5 μm microparticle base particles. In addition, the base particle release rate of the free base particles 18 ', which are the base particles to which the external additive 19 is not attached, is set to 15% or less. This base particle release ratio is the percentage of the amount of free base particles 18 'relative to the total amount of toner. Also,
1.5-2.5 μm microparticles have a base particle circularity of 0.85.
It is set to 0.95.

The circularity is given by: circularity = (perimeter of a circle having the same area as the projected area of a particle) / {contour length (perimeter) of particle projected view}.

[0019] Although the base particles liberation percentage is determined by analyzing the state of adhesion of the mother particle 18 and silica 19 of the toner, the toner analytical methods some methods have been conventionally performed. The image forming apparatus 1 of this example employs, for example, the following particle analyzer method.

That is, in the image forming apparatus 1 of this example,
As a method of analyzing the adhesion state between the base particles 18 of the toner T and the external additive 19, an annual meeting of the Electrophotographic Society of Japan (total 95
Times), "Japan Hardcopy '97", Collection of Papers, "New Evaluation Method of External Addition-Toner Analysis by Particle Analyzer-", Toshiyuki Suzuki, Toshio Takahara, Electrophotographic Society, 199
The toner analysis method (PT1000) disclosed on July 9 to 11, 2007 is employed.

In this toner analysis method, particles of toner T formed by adhering an external additive 19 made of silica (SiO ₂ ) to the surface of base particles 18 made of resin (C) are introduced into plasma. Excites the toner T particles,
This is a method of performing elemental analysis by obtaining emission spectra as shown in FIGS. 3A and 3B accompanying this excitation.

In FIG. 3, the horizontal axis of the emission spectrum indicates the time axis. First, as shown in FIG. 3A, when the toner T particles obtained by adhering the external additive (SiO ₂ ) to the resin base particles (C) of the toner T are introduced into the plasma, the mother particles (C) and the outer particles are formed. The additive (SiO ₂ ) emits light. At this time,
Since the base particles (C) and the external additive (SiO ₂ ) are simultaneously introduced into the plasma, the base particles (C) and the external additive (SiO ₂ ) are introduced.
₂ ) and emit light simultaneously. Thus, when the base particles (C) and the external additive (SiO ₂ ) emit light simultaneously, it is said that the base particles (C) and the external additive (SiO ₂ ) are synchronized. In other words, the state where the base particles (C) and the external additive (SiO ₂ ) are synchronized indicates a state where the external additive (SiO ₂ ) is attached to the base particles (C).

Further, as shown in FIG.
Base particles (C) or base particles (C) to which iO ₂ ) does not adhere.
When the external additive (SiO ₂ ) released from the gas is introduced into the plasma, the mother particles (C) and the external additive (S
iO ₂ ) emits light, but at this time, the base particles (C) and the external additive (SiO ₂ ) are introduced into the plasma at different times.
Light emission occurs at a time different from ₂ ) (for example, when the base particles are introduced into the plasma before the external additives, the base particles emit light first, and thereafter the external additives emit light after a delay).

As described above, the base particles (C) and the external additives (Si
O ₂ ) emits light at different times from each other,
It is said that the base particles (C) and the external additive (SiO ₂ ) are not synchronized (that is, asynchronous). In other words, the state in which the base particles (C) and the external additive (SiO ₂ ) are asynchronous is as follows:
This means that the external additive (SiO ₂ ) does not adhere to the base particles (C), and the base particles and the external additives are free base particles and free external additives, respectively.

Further, in FIGS. 3 (a) and 3 (b), the height of the light emission signal indicates the intensity of the light emission, and the intensity of the light emission is not the size or shape of the particle, but the intensity within the particle. It is proportional to the number of atoms of the element (C, SiO ₂ ) contained. Then, in order to express the emission intensity of the element as the size of the particles, when light emission of the base particles (C) and the external additive (SiO ₂ ) is obtained as shown in FIG. 4, these base particles (C) And spherical particles made only of the external additive (SiO ₂ ), the base particles (C) and the external additive (Si
O ₂ ). The true sphere particles at this time are called equivalent particles, and the particle size is called an equivalent particle size. Since the external additive is very small, the particles cannot be detected one by one. Therefore, the emission signal of the detected external additive is added to be converted into one equivalent particle and analyzed. . The equivalent particle size of the equivalent particles obtained by the respective emission spectra of the base particles and the external additive is calculated by
Is plotted for each particle, an equivalent particle size distribution diagram of the toner particles as shown in FIG. 5 is obtained.

In FIG. 5, the horizontal axis is the equivalent of the base particle (C).
The vertical axis represents the external additive (SiO 2). _TwoTable) Equivalent particle size
are doing. The equivalent particles on the horizontal axis represent the external additive (Si
O_Two) Represents an asynchronous parent particle (C) without attachment
ing. In that case, the external additive less than the specified external additive concentration
Are also shown on this horizontal axis, and the non-
Synchronous mother particles (C). Also, the equivalent on the vertical axis
The particles are made of an asynchronous external additive (S) released from the base particles (C).
iO_Two). In addition, not on the horizontal and vertical axes
The equivalent particles are obtained by adding an external additive (SiO 2) to the base particles (C)._Two) Adheres
Represents the synchronized toner T. Like this
The external additive (Si) to the base particles (C) of the toner T
O_Two) Is analyzed.

Further, as shown in FIG. 6, using the equivalent particle size distribution chart of the toner particles shown in FIG. 5, the adhesion state of carbon (C) in the base particles of the toner T and the external additive (SiO ₂ ). Is utilized using one approximate straight line α passing through the origin obtained by using the least squares method. The slope (equivalent particle size of external additive / equivalent particle size of base particle) θ of this approximate straight line α is the concentration of the external additive (SiO ₂ ) adhering (synchronizing) to the base particle (C). Represents. That is, the smaller the inclination θ, the smaller the amount of the synchronized external additive (SiO ₂ ), and the larger the inclination θ, the larger the synchronized external additive (SiO ₂ ).

In the present invention, using the equivalent particle size distribution chart of the toner particles shown in FIG. 5, the external additive 19 such as silica is determined from the state of the external additive 19 attached to the base particles 18 of the analyzed toner T. The mother particle release ratio of the additive 19 is determined.

In the present invention, the toner analysis is performed using the equivalent particle size distribution chart of the toner particles shown in FIG. 5, but the toner analysis method is different from the conventional toner analysis method other than the above-described particle analyzer method. It can also be used. However, it is preferable to use the particle analyzer method because the toner analysis can be performed more accurately and more easily.

The circularity of the base particles 18 can be determined by, for example, a flow type particle image analyzer (FPIA-2100; manufactured by Sysmex Corporation). In this flow type particle image analyzer, the particles of the toner T are guided to a flat sheath flow cell and made into a flat sample flow by a sheath liquid, and the sample flow is irradiated with strobe light. Then, the particles passing through the flow cell are captured as a focused still image particle image by the CCD camera through the objective lens,
The captured particle image is image-analyzed in real time, the projected area and the perimeter of each particle are measured, and the circle equivalent diameter and the circularity are calculated from the projected area and the perimeter.

In this example, the circularity of the base particles 18 is obtained by using the above-mentioned flow type particle image analyzer, but the circularity of the base particles 18 is calculated by the aforementioned flow type particle image analyzer. Other conventional methods for calculating circularity other than the calculation method can be used.However, since the circularity can be obtained more accurately and more easily, it is preferable to use the calculation method using the flow type particle image analyzer. preferable.

Further, the flow softening point of the base particles 18 of the toner T is preferably 100 ° C. to 120 ° C. This is because when the flow softening point of the base particles 18 becomes lower than 100 ° C., the toner T gradually fuses to the toner contact members such as the developing roller 16, the toner regulating blade 17, and the photoreceptor 2. Although this does not hinder practical use, it is not preferable that the size be further reduced. Also,
When the flow softening point of the base particles 18 is higher than 120 ° C., the low-temperature fixing becomes gradually poor. However, even if the flow softening point is increased to some extent, there is no problem in practical use. Absent.

Incidentally, the toner T used in the image forming apparatus of this embodiment may be either negative polarity or positive polarity toner. At least a coloring agent, a charge controlling agent, and other resins are added to the base particles 18, and a dispersant, a release agent (WAX), a magnetic material, other additives, and the like are also appropriately added.

The base particles 18 are made of a base particle material having a relatively low softening point and relatively soft at room temperature. Polystyrene and a copolymer such as a hydrogenated styrene resin, a styrene / isobutylene copolymer, an ABS resin, an ASA resin, AS resin, AAS resin, ACS resin, AES resin, styrene
P-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene cross-linked polymer, styrene
Butadiene / chlorinated paraffin copolymer, styrene / allyl / alcohol copolymer, styrene / butadiene rubber emulsion, styrene / maleic ester copolymer, styrene / isobutylene copolymer, styrene / maleic anhydride copolymer, acrylate Resin or methacrylate resin and its copolymer, styrene / acrylic resin and its copolymer such as styrene / acrylic copolymer, styrene / diethylamino / ethyl methacrylate copolymer, styrene / butadiene / acrylic acid Ester copolymer, styrene / methyl methacrylate copolymer, styrene / n-butyl methacrylate copolymer, styrene / methyl methacrylate / n-
Butyl acrylate copolymer, styrene / methyl methacrylate / butyl acrylate / 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 ・ Acrylic acid 2-
Ethylhexyl copolymer, styrene / n-butyl acrylate / ethyl glycol methacrylate copolymer, styrene / n-butyl methacrylate / acrylic acid copolymer, styrene / n-butyl methacrylate / maleic anhydride copolymer, styrene Butyl acrylate, isobutyl maleic acid half ester, divinylbenzene copolymer, polyester and its copolymer, polyethylene and its copolymer, epoxy resin, silicone resin,
One or a mixture of two or more of polypropylene and its copolymer, a fluorine resin, a polyamide resin, a polyvinyl alcohol resin, a polyurethane resin, and a polyvinyl butyral resin can be used.

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

As the charge control agent, an electron-accepting organic complex, chlorinated polyester, nitrophenic acid, quaternary ammonium salt, pyridinyl salt and the like can be used. As the release agent, polypropylene wax, polyethylene wax, ester wax, or the like can be used. As a dispersant, metal soap, polyethylene glycol, and the like can be used. As other additives, 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, etc., Fe ₃ O ₄ , Fe ₂ O ₃ , Cr
_An alloy or the like which exhibits ferromagnetism by heat treatment such as a metal oxide such as ₂ O ₃ or ferrite, or an alloy containing manganese and an acid can be used, and a preliminary treatment such as a coupling agent may be performed in advance. And, using these, a general kneading and pulverizing method,
The mother particles 18 are prepared by a spray-dry method, a polymerization method, or the like.

Examples of the external additive 19 include fine particles of a metal oxide such as silica, aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide and chromium oxide, fine particles of a nitride such as silicon nitride, and silicon carbide. It is possible to mix and use one or more kinds of fine particles of carbides, fine particles of metal salts such as calcium sulfate, barium sulfate, and calcium carbonate, and inorganic fine particles such as composites thereof, and organic fine particles such as acrylic fine particles. it can.
In addition to these surface treatment agents, in addition to HMDS, silane coupling agents, titanate coupling agents,
A fluorine-containing silane coupling agent, silicone oil, or the like can be used. The particle size of the external additive 19 is preferably 0.001 to 1 μm from the viewpoint of transportability and chargeability. The base particles 18 and the external additives 19 are dry-mixed with a high-speed fluid mixer such as a Henschel mixer or a Papen-Meyer or a mixer such as a mechanochemical method and adhered.

According to the toner T of this embodiment having the above-described configuration, the base particle release rate is set to 15% or less, and the circularity of the base particles 18 of fine particles having a particle size of 1.5 to 2.5 μm is set. Is set to 0.85 to 0.95, and the mother particle release rate is 1
Since the circularity of the base particles of the fine particles is set to a higher appropriate value in the toner of 5% or less, the free base particles may not be in contact with the toner such as the latent image carrier, the toner carrier, and the toner regulating member. In addition to reducing fusion to the member, the external additive can be more evenly attached to the base particles of the fine particles, and the fusion of the base particles of the fine particles to the toner contact member is also effective. it can be reduced to. As a result, filming of the toner contact member can be effectively suppressed. Therefore, according to the toner of this example, the durability of the toner contact member such as the latent image carrier, the toner carrier, and the toner regulating member can be improved, and good image quality can be obtained for a longer period. .

In particular, according to the toner of this example, the external additive 1
Since silica is used as 9 and an appropriate amount of silica adheres to the base particles 18, it is possible to prevent a large amount of heat from being taken away by the silica during heating and fixing. Since the surface of the base particles having a low melting point can be prevented from being excessively exposed due to being coated with the toner, the toner of this example can improve the low-temperature fixability while preventing filming on the toner contact member. it can.

On the other hand, according to the image forming apparatus 1 of this embodiment,
By using the toner T, the durability of the photoconductor 2, the developing roller 16, and the toner regulating blade 17 can be improved, and good image quality can be obtained for a longer period.

Further, since heat can be hardly transmitted to the base particles 18 having a low melting point, according to the image forming apparatus 1 of this example, the fusion of the toner to the photosensitive member 2, the developing roller 16, and the toner regulating blade 17 is prevented. While preventing it, and
Good low-temperature fixability can be obtained.

Actually, with respect to the toners of Examples 1 to 3 of the present invention and the toners of Comparative Examples 1 and 2 for comparison with Examples 1 to 3, the developing roller 16
Further, an experiment for measuring the filming of the toner on the toner regulating blade 17 was performed. Table 1 shows the toner used and the external addition processing conditions in this measurement experiment, and the experimental results. The evaluation method of the experimental result is 10K (1K = 1000).
When filming of the toner T does not occur in any of the developing roller 16 and the toner regulating blade 17 by the number of printed sheets, the evaluation is good. when the filming of the toner T has occurred in any one of the toner regulating blade 17 was evaluated as bad.

[0044]

[Table 1]

As shown in Table 1, the toner of Example 1 belonging to the present invention is a polymerized toner in which the base particles 18 used are produced by a polymerization method, and the toner of Example 2 and the toner of Example 2 belonging to the present invention. Each of the toners of Comparative Examples 1 and 2, which do not belong to the present invention, is a pulverized toner in which the used base particles 18 are manufactured by a pulverizing method. Further, the toner of the toner of Example 3 belonging to the present invention is a pulverized toner. Is a pulverized spherical toner produced by a pulverization method and subjected to a spheroidizing treatment.

In addition, each of the toners used was an external additive 19
Silica (SiO ₂ ) is used as the
G810G (Cabot). Further, external addition conditions are all examples also apparatus used in external treatment of the mother particles 18 and the silica is Henschel 20C (manufactured by Mitsui Mining), the rotational speed of apparatus used in the external treatment 2850rp
m.

Further, the external addition processing time was 5 minutes in Example 1, 4 minutes in Example 2, 3 minutes in Example 3,
Comparative Example 1 is 1 minute, and Comparative Example 2 is 4 minutes. Furthermore,
The circularity of the base particles of 1.5 to 2.5 μm microparticles was 0.939 in Example 1, 0.882 in Example 2, 0.901 in Example 3, and Example 1 is 0.88
2, Comparative Example 2 had 0.835, and 1.5 to 1.5.
The base particle circularity of the base particles of 40 μm was 0.9 in Example 1.
Example 2 has 0.918 and Example 3 has 0.93.
918, Comparative Example 1 was 0.918, and Comparative Example 2 was 0.918.
Is 0.902.

Further, the mother particle free ratio of the mother particles to which silica was not adhered was 3.1% in Example 1 and 7.% in Example 2.
7%, Example 3 is 12.3%, Comparative Example 1 is 16.5%, and Comparative Example 2 is 8.3%.

[0049] As apparent from Table 1, in each of the toner T in the first to third embodiments, either, even if the number of printed sheets becomes 10K sheets, either the filming of the development roller 16, and a toner regulating blade 17 Did not occur and good results were obtained. On the other hand, with the toner T of Comparative Example 1, the number of printed sheets was 4K, and no filming occurred on the developing roller 16, but filming occurred on the toner regulating blade 17, and an unfavorable result was obtained. Further, with the toner T of Comparative Example 2, the number of prints was 3K, and no filming occurred on the toner regulating blade 17, but filming occurred on the developing roller 16, and an undesirable result was obtained.

[0050] Thus, you set the base particles liberation ratio below 15%, by setting the base particle circularity of microparticles 1.5~2.5μm to 0.85 to 0.95, of the fine particles photoreceptor 2 in the toner containing base particles, the developing roller 16, and it was found that the filming of the toner contact member such as a toner regulating blade 17 can be effectively suppressed.

Table 1 shows data when silica is used as an external additive. However, the present invention can use other external additives. However, the present invention is desirably applied to a toner using at least silica as an external additive because the above-described effects can be reliably obtained.

Further, the toner and the image forming apparatus of the present invention are not limited to the above-mentioned examples, and any toner T having at least mother particles and an external additive and an image forming apparatus using the toner T may be used. It can be applied to any toner and image forming apparatus.

[0053]

As is apparent from the above description, according to the toner of the present invention, the base particle release rate is set to 15% or less, and the base particles of the fine particles having a particle size of 1.5 to 2.5 μm. of setting the roundness to 0.85-0.95, since the mother particle free rate is set circularity of the mother particles of the fine particles in the toner is not more than 15% higher appropriate value, free The base particles can be prevented from being fused to toner contact members such as a latent image carrier, a toner carrier, and a toner regulating member, and the external additive can be more uniformly adhered to the base particles of fine particles. As a result, the fusion of the base particles of the fine particles to the toner contact member can be effectively reduced. As a result, filming of the toner contact member can be effectively suppressed. Therefore, according to the toner of this example, the durability of the toner contact member such as the latent image carrier, the toner carrier, and the toner regulating member can be improved, and good image quality can be obtained for a longer period. .

In particular, according to the toner of the second aspect,
Since silica is used as an external additive, and the amount of silica adhering to the base particles is an appropriate amount, it is possible to prevent a large amount of heat from being taken away by the silica during heating and fixing. from being coated because the surface of the base particles of the low melting point can be prevented from being exposed excessively to, this toner, while preventing filming to toner contact member, it is possible to improve the low-temperature fixability.

On the other hand, according to the image forming apparatus of the present invention, by using this toner, the durability of the above-mentioned toner contact member can be improved, and good image quality can be obtained. Further, by using the toner of the second aspect of the present invention, heat can be hardly transmitted to the low melting point base particles. Therefore, according to the image forming apparatus of the present invention, the fusion of the toner to the toner contact member can be prevented. And good low-temperature fixability can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a full-color intermediate transfer type image forming apparatus which is an example of a conventional image forming apparatus used as an example of an embodiment of the image forming apparatus according to the present invention.

FIGS. 2A and 2B schematically show an example of a conventional developing device used in the image forming apparatus of the example shown in FIG. 1, wherein FIG. 2A is a cross-sectional view thereof, and FIG. FIG. 4 is a diagram illustrating toner particles.

FIG. 3 is a view for explaining an example of a conventional toner analysis method for use in analyzing the state of adhesion between toner base particles and external additives.

FIG. 4 is a diagram illustrating equivalent particles and equivalent particle sizes used in the toner analysis method shown in FIG.

5 is a diagram showing an analysis result by the toner analysis method shown in FIG.

6 is a diagram showing, based on the analysis result shown in FIG. 5, the state of adhesion between the mother particles of the toner and the external additive by using a single approximate straight line α passing through the origin using the least squares method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Latent image carrier (photoreceptor), 3, 4,
5, 6 developing device, 7 intermediate transfer member, 16 toner carrier (developing roller), 8 transfer device, 9 transfer material, 10 fixing device, 17 toner regulating member (toner regulating blade), 1
8: Base particles, 19: External additive, 18 ': Free base particles, 1
9 ': free external additive, T: toner

Claims (3)

[Claims] 1. A toner having at least a large number of base particles and a large number of particles of an external additive, wherein the free particle to which the external additive is not attached has a base particle release rate of 15% or less. In addition, among the base particles, the circularity of the base particles of fine particles having a particle size of 1.5 to 2.5 μm is set to 0.85 to 0.95. 2. The toner according to claim 1, wherein the external additive is silica. 3. A latent image carrier on which an electrostatic latent image is formed; a toner carrier for transporting toner to develop an electrostatic latent image on the latent image carrier; 3. An image forming apparatus, comprising: at least a developing device having a toner regulating member that regulates at least toner conveyed toward the image carrier, wherein the toner is the toner according to claim 1 or 2.