JP2000047425A - Toner and image forming device using this toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an external additive from being liberated from toner at the time of contact development or contact transfer to reduce the occurrence of filming. SOLUTION: Toner T is set so that the inclination (grain size of external additive/grain size of base grain) θ of an approximate straight line α obtained by approximating the distribution of grain size of an external additive (SiO2) to the grain size of base grain (C) by minimum square method is 0.6 or less. Accordingly, the quantity of the external additive adhered to the base grain (C) and the grain size are limited, and the liberation of the external additive (SiO2) from the base grain (C) is reduced at the contact development step with a latent image carrier or the contact transfer step with a transfer device in image forming process. Thus, the staying of the external additive (SiO2) in the cleaning part of the latent image carrier is suppressed, and the filming can be reduced.

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 a toner for developing an electrostatic latent image on a latent image carrier, and a developed image obtained by developing the electrostatic latent image on the latent image carrier with the toner. Belongs to the technical field of an image forming apparatus designed to transfer an image onto a transfer material such as paper, and particularly, the technical field of a toner having excellent fluidity and chargeability, and a residue remaining on a latent image carrier after transfer. It belongs to the technical field of an image forming apparatus designed to clean and remove toner.

[0002]

2. Description of the Related Art In an image forming apparatus, an electrostatic latent image on a latent image carrier is developed with toner, the developed image is transferred to a transfer material such as paper, and the latent image is transferred onto the transfer material. A transfer image of the electrostatic latent image exposed on the carrier is obtained.

FIG. 10 is a diagram schematically showing a full-color intermediate transfer type image forming apparatus which is an example of such a conventional image forming apparatus. As shown in FIG. 10, in the image forming apparatus 1, an image is transferred from a latent image carrier (hereinafter, referred to as an OP).
C) 2 as an electrostatic latent image, and the electrostatic latent image on the OPC 2 is yellow, magenta,
Each of the cyan and black developing units 3, 4, 5, and 6 is sequentially developed (the order of each color is arbitrary) to be visualized, and further, OPC
After the developed image on 2 is color-matched by the transfer device 7 and transferred to the transfer material 8, it is fixed by the fixing device 9, so that a desired image can be obtained on the transfer material 8.

After the developed image is transferred to the transfer material 8, the residual toner T 'remaining on the OPC 2 is removed by the cleaning blade 10, and the residual toner box 1 is removed.
1

By the way, the toner T used in such a conventional image forming apparatus 1 is supplied from the respective toner carrying members 3a, 4a, and 4c supplied from the respective toner supply members 3c, 4c, 5c, 6c of the respective developing devices. The toner T on 5a, 6a is uniformly thinned and uniformly charged by each of the toner regulating blades 3b, 4b, 5b, 6b and is conveyed toward the OPC 2, but each toner carrier 3a, 4a, 5a, 6a. And each toner blade 3b, 4
In order to reliably transport the toner T through the gaps b, 5b, and 6b toward the OPC 2, the toner T needs to have good fluidity and good chargeability. Therefore, the conventional toner T is
As shown in FIG. 11, base particles 1 made of resin (carbon: C)
An external additive 13 made of silica (SiO ₂ ) is adhered to the surface of No. ₂ to improve its fluidity and chargeability.

However, in the toner T formed by attaching the external additive 13 to the base particles 12 as described above, the external additive 13 released from the base particles 12 is present and is free. Since the external additive 13 is relatively harder than the mother particles 12, the free external additive 13 in the residual toner T 'is
0 when removed by OPC2 as shown in FIG.
Contact portion (nip portion) 2 with cleaning blade 10
The film sticks and stays at a, so-called filming occurs. When such filming occurs, a high-quality image cannot be obtained.

Therefore, in the toner T used in the image forming apparatus 1, the occurrence of filming can be suppressed by reducing aggregates (lumps) of the external additive 13 released from the base particles 12. 7-99438. According to this publication, the occurrence of filming due to the external additive 13 in the cleaning blade 10 is reduced.

[0008]

However, as a result of various studies on such filming, the present inventors have found that even the external additive 13 adhered to the base particles 12 in the toner T adheres to the cleaning blade 10. Was found to cause filming. That is, in the process of developing the electrostatic latent image of the OPC 2 and the process of transferring the developed image of the OPC 2, the external additive 13 attached to
Stress is repeatedly applied during contact development when contacting with the transfer agent 2 and contact transfer when contacting with the transfer device 7. It has been found that the external additive 13 is released from the base particles 12 due to the stress.

For this reason, as disclosed in the above-mentioned publication, the external additive 13 released from the base particles 12 in the toner T is used.
Even if the agglomerates (lumps) are reduced, the external additive 13 released from the mother particles 12 due to stress stays in the nip portion 2a of the OPC 2 and is fixed, thereby causing filming.

[0010] Even if the toner T does not include the external additive 13 in a lump, if the liberated external additive 13 having a small particle diameter is present in a large amount, the external additive 13 is removed from the developing process. It was found that secondary agglomeration was caused by electrostatic agglomeration during contact development with the OPC 2 at the time of contact development with the transfer device 7 in the transfer step, thereby forming lumps. In particular, the stress of the toner T received during the contact development with the OPC 2 is often higher than the stress in the developing device, and the developing device used in the high image quality developing system generally rotates at a different peripheral speed with respect to the OPC 2. Therefore, it was also found that secondary aggregation of the external additive 13 is likely to occur because the stress on the toner T is large.

As described above, in the toner disclosed in the above-mentioned publication, the external additive 13 released from the base particles 12 in the toner T is used.
It cannot be said that filming cannot be sufficiently and effectively prevented since the generation of lumps due to secondary aggregation cannot be prevented.

In addition, in the toner disclosed in the above-mentioned publication, when the toner is repeatedly subjected to stress at the time of contact development or contact transfer, the external additive may be released from the base particles. Therefore, the life of the toner is limited, and further extension of the life of the toner cannot be expected.

[0013] The present invention has been made in view of such circumstances, and an object of the present invention is to prevent filming from occurring more reliably, and to further extend the life. To provide toner.

Another object of the present invention is to provide an image forming apparatus capable of suppressing release of an external additive from a toner during contact development or contact transfer to further reduce the occurrence of filming. It is.

[0015]

In order to solve this problem, a toner according to the present invention is a toner comprising a large number of base particles and a large number of external additives respectively attached to these base particles. The slope of the approximate line (the particle diameter of the external additive / the particle diameter of the mother particle) obtained by approximating the distribution of the particle diameter of the external additive with respect to the particle diameter of the mother particle by the least square method is 0.6 or less. Is set as follows.

Further, the invention according to claim 2 is characterized in that the external additive released from the mother particles is set to be 5% or less based on the whole toner. Further, in the invention according to claim 3, the value obtained by dividing the average particle size of the external additive attached to the base particles by the average particle size of the entire external additive is set to be larger than 1. It is characterized by:

Further, according to a fourth aspect of the present invention, in a toner comprising a large number of base particles and a large number of external additives respectively attached to these base particles, an average of the external additives attached to the base particles is provided. The value obtained by dividing the particle size by the average particle size of the entire external additive is 1
It is characterized in that it is set to be larger than.

Further, the image forming apparatus according to the present invention is characterized in that:
A latent image carrier on which an electrostatic latent image is formed, a developing device for developing the electrostatic latent image on the latent image carrier with toner, a transfer device for transferring a developed image on the latent image carrier, Cleaning means for cleaning the residual toner remaining on the latent image carrier after the transfer, wherein the toner is the toner according to any one of claims 1 to 4.

[0019]

In the toner according to the first aspect of the present invention, the distribution of the particle diameter of the external additive with respect to the particle diameter of the base particle is approximated by the least square method. By setting (diameter / particle diameter of base particles) to be 0.6 or less, the amount and particle size of the external additive adhering to the base particles are limited. Thereby, during the image forming process,
During the contact development step with the latent image carrier or the contact transfer step with the transfer device, the release of the external additive from the base particles is reduced. Therefore, stagnation of the external additive in the cleaning portion of the latent image carrier is suppressed, and filming is reduced.

According to the second aspect of the present invention, the re-aggregation of the external additive is prevented by setting the amount of the external additive released from the base particles to be 5% or less of the whole toner. And filming is more effectively reduced.

Further, according to the third and fourth aspects of the present invention, the value obtained by dividing the average particle size of the external additive attached to the base particles by the average particle size of the entire external additive is larger than 1. By setting the external additive having a large particle size, almost all of the external additive having a large particle diameter adheres to the mother particle and serves as a synchronous external additive, and most of the asynchronous external additive released from the mother particle is an external additive having a small particle size. Become.

This also reduces the inclination of the approximate straight line in the first aspect, thereby reducing filming.

Further, in the image forming apparatus according to the fifth aspect of the present invention, by using one of the toners according to the first to fourth aspects, the external additive is prevented from staying in the cleaning section of the latent image carrier. Is done. Therefore, occurrence of filming on the latent image carrier is reduced.

Further, in the toner and the image forming apparatus of the present invention, even if the toner is repeatedly subjected to stress during contact development or contact transfer, release of the external additive from the base particles is suppressed. The service life and the service life of the image forming apparatus are further extended.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating an example of a conventional toner analysis method used for analyzing the state of adhesion between a mother particle and an external additive of a toner, which is an example of an embodiment of the toner according to the present invention.

First, in the toner of this example, the toner T
It is necessary to analyze the adhesion state between the base particles and the external additive.
Therefore, in the toner T of this example, as a method of analyzing the toner, the annual meeting of the Society of Electrophotography (95 times in total)
ardcopy '97 ", Collection of Papers," New Evaluation Method of External Addition-Toner Analysis by Particle Analyzer-", Toshiyuki Suzuki, Toshio Takahara, sponsored by the Society of Electrophotography, July 9-11, 1997
The toner analysis method disclosed in Japanese Patent Application Laid-Open No. H10-26084 is adopted.

In this toner analysis method, particles of toner T formed by adhering an external additive made of silica (SiO ₂ ) to the surface of base particles made of resin (C) are introduced into plasma. This is a method of performing elemental analysis by exciting toner T particles and obtaining an emission spectrum as shown in FIG. 1 accompanying the excitation.

In FIG. 1, the horizontal axis of the emission spectrum indicates the time axis. First, as shown in FIG. 1A, 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).

Thus, 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 ) is not attached to the base particles (C).

Further, in FIG. 1, 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 element contained in the particle ( C, SiO ₂ ). 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. 2, these base particles (C) and the external additive assuming particles (SiO ₂₎ was only truly spherical, it is expressed as particle diameter thereof of the mother particle (C) and the external additive (SiO _2). The true spherical particles at this time are called equivalent particles,
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. .

When the equivalent particle size of the equivalent particles obtained by the respective emission spectra of the base particles and the external additives is plotted for each particle of the toner T, the equivalent particle size of the toner particles as shown in FIG. A distribution map is obtained.

In FIG. 3, the horizontal axis represents the equivalent particle size of the base particles (C), and the vertical axis represents the equivalent particle size of the external additive (SiO ₂ ). The equivalent particles on the horizontal axis represent the external additive (Si
O ₂ ) represents the asynchronous parent particles (C) to which no particles are attached, and the equivalent particle on the vertical axis represents the asynchronous external additive (SiO ₂ ) released from the parent particles (C). .
The equivalent particles not on the horizontal axis and the vertical axis represent the synchronous toner T in which the external additive (SiO ₂ ) is attached to the base particles (C). In this way, the state of attachment of the external additive (SiO ₂ ) to the base particles (C) of the toner T is analyzed.

By the way, the toner T used in the image forming apparatus of this embodiment may be either negative polarity or positive polarity toner. In that case, the mother particles are at least a coloring agent,
It is composed of a charge control agent and a resin, and may further use a dispersant, a release agent (WAX), a magnetic material, and other additives.

As the base 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 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-based resin or methacrylate-based resin and its copolymer, Styrene / acrylic resin and its copolymer, for example, styrene / acrylic copolymer, styrene / diethylamino / ethyl methacrylate copolymer, styrene / butadiene / acrylic 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 / acrylate / maleate copolymer, styrene / methyl methacrylate / 2-ethylhexyl acrylate Styrene-n-butylarylate-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, polypropylene and its copolymer, fluorine resin, polyamide resin, polyvinyl alcohol resin, polyurethane resin, polyvinyl butyral resin, etc. blended one or more kinds Can be used.

The coloring agents include carbon black, spirit black, nigrosine, rhodamine,
Triaminotriphenylmethane, cationic, dioxazine, copper phthalocyanine, berylen, azo, gold-containing azo pigment, azochrome complex, carmine, benzidine, solar pure yellow 8G, quinacridone, polytungstophosphoric acid, indasulene blue, Sulfonamide derivatives and the like can be used.

Further, as the charge control agent, an electron-accepting organic complex, chlorinated polyester, nitrophenic acid,
Secondary ammonium salts, pyridinyl salts and the like can be used. Further, as the release agent, polypropylene wax, polyethylene wax, or the like can be used. Further, 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.

Further, as the magnetic agent, Fe, Co, N
i, Cr, Mn, Zn or other metal powder, Fe ₃ O ₄ , Fe
Metal oxides such as ₂ O ₃ , Cr ₂ O ₃ , and ferrite, alloys that exhibit ferromagnetism by heat treatment such as alloys containing manganese and acid, and the like can be used. I do not care. Then, these are mixed by using a general kneading and pulverizing method, a spray-dry method, a polymerization method or the like, thereby producing mother particles.

On the other hand, various external additives can be used, for example, inorganic fine particles such as metal oxides such as silica, alumina and titanium oxide, and composite oxides thereof;
Organic fine particles such as acrylic fine particles can be used.
Further, as these surface treatment agents, silane coupling agents, titanate coupling agents, fluorine-containing silane coupling agents, silicone oils, and the like can be used. The hydrophobicity of the external additive treated with these treating agents is preferably 60% or more by a conventional methanol method. If it is less than this, in high temperature and high humidity,
It is not preferable because the chargeability and the fluidity tend to decrease due to the adsorption of moisture. The particle size of the external additive is preferably from 0.001 to 1 μm from the viewpoint of transportability and chargeability. The amount of the external additive to be added is 0.1 to the toner base particles.
It is preferably 1 to 5 wt%. If the amount is further increased, the probability that the external additive becomes asynchronous with the toner increases,
Secondary aggregation or the like of the external additives frequently occurs, which causes a decrease in the chargeability and an increase in the transport streak.

The external additive is not limited to one type, and a mixture of two or more types can be used. Then, the toner T of the present example is formed by dry-mixing the mother particles and the external additive with a high-speed fluid mixer such as a Henschel mixer or a Papen Meyer or a mixer such as a mechanochemical method and attaching them to each other, thereby adhering to each other. Is done.

As the toner carrier used in the developing device in the image forming apparatus of this embodiment, any material which can be formed as a toner carrier, such as magnetic, non-magnetic, conductive, insulating, metal, rubber, resin, etc. Can be used. For example, in terms of material, aluminum, nickel,
Metals such as stainless steel, natural rubber, silicone rubber, urethane rubber, butadiene rubber, chloroprene rubber, neoprene rubber, rubber such as NBR, styrene resin, vinyl chloride resin, polyurethane resin, polyethylene resin, methacryl resin, nylon resin, etc. Can be used.
It goes without saying that these materials can be used even if they are coated on the upper layer. In that case, as the coating material,
Polyethylene, polystyrene, polyurethane, polyester, nylon, acrylic and the like can be used. In addition, as a form, inelastic body, elastic body, single layer, multilayer, film,
Everything such as rollers can be used. Also,
The surface roughness of the toner carrier is set to Rz1 to 10 μm in order to secure toner transportability.

Further, as the material of the toner supply member used in the developing device in the image forming apparatus of the present embodiment, it is preferable to set an elastic body to stabilize the contact of the toner carrier. In this example, as the material of the toner supply member,
Polyurethane foam, polystyrene foam, polyethylene foam, polyester foam, ethylene propylene foam, nylon foam, silicone foam and the like can be used. Note that the foaming cell of the toner supply means can use either a single cell or a continuous cell, but a single cell is preferable. This is because, when the foam cells are open cells, the toner enters the inside of the foam cells of the supply means, and eventually causes the toner to aggregate inside and on the surface layer, causing a decrease in toner transportability and a transport streak in the regulating section. This is because Therefore, single cells are preferred. A hardness of 10 ° to 40 ° (measured by Asker C hardness meter) can be used, but a hardness of 35 ° to 40 ° having a large scraping effect of the residual toner on the toner carrier is optimal. preferable.
Further, those having a resistance value of 10 ³ to 10 ⁷ Ωcm (volume resistance value) can be used.

In this embodiment, the foam material is used, but it goes without saying that a rubber material having elasticity may be used. Specifically, conductive agents such as carbon are dispersed in silicon rubber, urethane rubber, natural rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, butyl rubber, ethylene propylene rubber, epichlorohydrin rubber, nitrile butadiene rubber, and acrylic rubber. Molded ones can be used.

Further, as the toner regulating means used in the developing device in the image forming apparatus of the present embodiment, stainless steel,
A material in which an elastic chip such as an R-shaped rubber is formed on a plate material such as copper, iron, and resin can be used. As a rubber chip, silicon 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 and a conductive agent such as carbon are used. Dispersion molded products can be used. Further, those obtained by integrally molding these rubber materials alone or those constituted by a plate material alone can also be used.
Further, it goes without saying that the above-mentioned material can be used even if it is coated with a resin on the upper layer. As the coating material, polyethylene, polystyrene, nylon, polyurethane,
Polyester and the like can be used.

Further, as a cleaning blade used in the image forming apparatus of this embodiment, a cleaning blade formed by forming an elastic chip such as rubber on a plate material such as stainless steel, copper, iron and resin can be used. As the rubber chip, 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, molded acrylic rubber, or the like, After that, those polished or cut can be used.

In the toner T of this embodiment, the toner analysis is performed by the above-described analysis method. In the toner of this example, silica particles are used as an external additive. FIG.
As shown in the figure, the adhesion state between the carbon (C) 12 and the external additive (SiO ₂ ) 13 in the base particles of the toner T analyzed by the above-described analysis method is represented by the origin obtained by using the least square method. Pass 1
The book approximate line α is used. The slope (equivalent particle size of external additive / equivalent particle size of base particle) θ of the approximate line α is the external additive (S) attached to (synchronized with) the base particle (C) 12.
iO ₂ ) 13. That is, the inclination θ is small enough synchronization with that external additive (SiO ₂₎ 13 concentration is low, this case is outside synchronized additive (SiO ₂₎
13 is small and the particle size is small. In addition, the larger the inclination θ is, the more the external additive (Si
The concentration of O ₂ ) 13 is high. In this case, the amount of the synchronized external additive (SiO ₂ ) 13 is large and the particle size is large.

As the amount of the synchronized external additive (SiO ₂ ) 13 increases, the inclination θ increases, and the amount of the free external additive (SiO ₂ ) 13 due to stress increases, and filming occurs. Cheap. Also, an external additive (SiO ₂ ) 13
The larger the particle size of the film, the larger the inclination θ, the more easily the external additive (SiO ₂ ) 13 is released due to stress, and the more the filming occurs.

The toner T of this example has an approximate straight line α related to the concentration of the external additive (SiO ₂ ) 13 which is synchronized.
Is set to be equal to or less than 0.6.

According to the toner T of this example having the above-described configuration, in the toner T in which the base particles (C) 12 and the external additive (SiO ₂ ) 13 are synchronized, the base particles (C) 12 The toner T is adjusted so that the slope θ of the approximate straight line α based on the concentration of the external additive (SiO ₂ ) 13 with respect to the particle size is 0.6 or less.
, The external additive (SiO 2) adhering to the toner T
₂ ) The total amount of 13 and the particle size of the external additive (SiO ₂ ) 13 adhering to one base particle (C) 12 are adjusted so that the number of filming generated even when the number of printed sheets is increased hardly changes. Can be restricted. Thus, during the contact developing step or the contact transfer step during the image forming process, the liberation of the external additive (SiO ₂ ) 13 from the synchronized mother particles (C) 12 of the toner T can be reduced. it can,
In other words, the generation of the asynchronous external additive (SiO ₂ ) 13 can be reduced. Therefore, OPC2
The stagnation of the external additive (SiO ₂ ) 13 in the upper nip portion 2a can be more effectively reduced, and the occurrence of filming can be effectively suppressed.

Actually, the toner T of this example in which the slope θ of the approximate line α is set to 0.6 and the toner T not included in the present invention in which the slope θ of the approximate line α is set to 0.7 As a result of performing an image forming test using the image forming apparatus 1 having the cleaning blade 10 as shown in FIG. 10 described above, the result as shown in FIG. 5 was obtained. As the toner used in the test, a toner using silica fine particles was used, and the measurement was performed by detecting the emission spectrum of Si (the same applies to other tests described below).

As is apparent from FIG. 5, the approximate straight line α
In the case of the toner T whose inclination θ is set to 0.7, when the number of printed sheets increases, an external additive (Si
The number of filming due to the external additive (SiO ₂ ) 13 generated by the external additive (SiO ₂ ) 13 is increased in the case of the toner T in this example, although the number of filming due to the O ₂ ) 13 rapidly increases. The result was that there was little change or only a very slight increase was obtained. It was found that in the toner T of this example, the occurrence of filming due to the external additive (SiO ₂ ) 13 was reduced.

According to the toner T of this example, even if the toner T is repeatedly subjected to stress during contact development or contact transfer, the external additive (SiO ₂ ) 13
Is suppressed, so that the life of the toner T is further extended.

The present invention is not limited to silica fine particles as an external additive, but various materials can be used as described above. Therefore, when conducting an analysis test of the toner, the measurement can be similarly performed even when an external additive other than silica is used by appropriately selecting the emission spectrum of the element to be detected according to the material of the external additive. it can. In this case, for example, the emission spectrum of Ti may be detected and processed when titanium oxide is used as the external additive, and the emission spectrum of Al may be detected when alumina is used.

FIG. 6 illustrates another example of the embodiment of the toner according to the present invention, and is a normal distribution diagram of the toner particle diameter obtained from the analysis result shown in FIG. As another example of the embodiment of the toner according to the present invention, in addition to the above-mentioned inclination θ of 0.6 or less, the toner T is made of an asynchronous external additive (SiO ₂ ) 13 shown in FIG. The amount is 5 for the total toner amount
%. By thus setting the amount of the external additive (SiO ₂₎ 13 asynchronous, since the external additive (SiO ₂₎ 13 will be able to prevent the reaggregation, it is possible to reduce the filming .

Actually, the asynchronous external additive (SiO ₂ ) 13
While increasing the amount of
As a result of the image formation test performed in the same manner as described above, the results shown in FIG. 7 were obtained.

As is apparent from FIG. 7, the amount of the asynchronous external additive (SiO ₂ ) 13 is 5% of the total toner amount.
%, When the number of printed sheets increases, the number of filming by the external additive (SiO ₂ ) 13 generated on the OPC ₂ suddenly increases, but the asynchronous external additive (Si
When the amount of O ₂ ) 13 is 5% or less of the total amount of toner, the external additive (Si
The result was that the number of filmings due to O ₂ ) 13 increased only slightly, and did not substantially affect the image.
That is, even in the toner T of this example, the external additive (SiO ₂ )
13, the occurrence of filming was found to be reduced. Also, with the toner T of this example, similarly to the toner T of the above-described example, the life of the toner T is further extended.

FIG. 8 illustrates still another example of the embodiment of the toner according to the present invention, and is a normal distribution diagram of the particle diameter of the external additive obtained from the analysis result shown in FIG. As another example of the embodiment of the toner according to the present invention, as shown in FIG. 8, toner T has an average particle diameter of synchronous external additive (SiO ₂ ) 13 of the entire external additive (SiO ₂ ) 13. So that it is larger than the average particle size,

[0058]

(Equation 1)

Is set to be as follows. With such a configuration, in the toner T of this example, the external additive (SiO ₂ ) 13 having a large particle diameter almost adheres to the base particles (C) 12 and is combined with the synchronous external additive (SiO ₂ ) 13. Has become. The liberated asynchronous external additive from the mother particles _{(C) 12 (SiO 2)} 13 , are mostly has a small external additive (SiO ₂₎ 13 particle size.

Therefore, the asynchronous external additive (SiO ₂ ) 13 is also reduced by the toner T in this example at the time of the contact development step or the contact transfer step during the image forming process, so that the nip portion on the OPC ₂ is reduced. The retention of the external additive (SiO ₂ ) 13 in 2a can be more effectively reduced, and the occurrence of filming can be effectively suppressed.

Actually, the toner T of this example in which the average particle size of the synchronous external additive (SiO ₂ ) 13 is set to be larger than the average particle size of the entire external additive (SiO ₂ ) 13, The average particle size of the agent (SiO ₂ ) 13 is smaller than that of the external additive (SiO ₂ ) 13.
An image forming test was performed in the same manner as described above using a toner T not included in the present invention, which was set to be smaller than the overall average particle diameter. As a result, the result shown in FIG. 9 was obtained.

As is apparent from FIG. 9, the average particle size of the synchronous external additive (SiO ₂ ) 13 is smaller than that of the external additive (SiO ₂ ) 13.
In the case of the toner T smaller than the entire average particle diameter, when the number of printed sheets increases, an external additive (SiO 2) generated on the OPC 2 is generated.
₂ ) Although the number of filmings due to 13 suddenly increases, in the case of the toner T of this example, even if the number of prints increases, the number of filmings due to the external additive (SiO ₂ ) 13 almost disappears. The result is that it does not change,
It was also found that even with the toner T of this example, the occurrence of filming due to the external additive (SiO ₂ ) 13 was reduced. Also,
According to the toner T of this example, similarly to the toner T of the above-described example, the life of the toner T is further extended.

In the above-described example, the toner analysis method disclosed in the above-mentioned collection of papers is used as a method for analyzing the adhesion state between the mother particles of the toner and the external additive. It goes without saying that any toner analysis method can be used as long as it can obtain the average particle diameter of the equivalent particle diameter of the synchronous toner and the average particle diameter of the equivalent particle diameter of the entire toner.

Further, the image forming apparatus according to the present invention is not limited to the image forming apparatus 1 shown in FIG. 10, and at least the residual toner T 'on the OPC 2 is cleaned by the cleaning blade 10 after development. The present invention can be applied to any image forming apparatus as long as it is an image forming apparatus.

Further, in each of the above-described examples, silica (SiO ₂ ) is used as the external additive 13. However, any silica that adheres to the base particles (C) and improves the fluidity of the toner T can be used. For example, a material other than silica can be used as the external additive 13.

[0066]

As is apparent from the above description, according to the toner of the present invention, the amount and the particle size of the external additive adhering to the base particles are limited, so that during the image forming process, During the contact development step with the latent image carrier or the contact transfer step with the transfer device, the release of the external additive from the base particles can be reduced. Therefore, stagnation of the external additive in the cleaning section of the latent image carrier can be suppressed, and filming can be reduced.

Further, according to the toner and the image forming apparatus of the present invention, even if the toner is repeatedly subjected to stress during contact development or contact transfer, release of the external additive from the base particles can be suppressed. Thus, the life of the toner can be further extended. In particular, according to the second aspect of the present invention, since reaggregation of the external additive is prevented, filming can be more effectively reduced.

According to the third and fourth aspects of the present invention,
Most of the external additives with large particle diameters are synchronous external additives, and most of the asynchronous external additives are external additives with small particle diameters.
Since the inclination of the approximate straight line in the first aspect is reduced, filming can be further reduced.

Further, according to the image forming apparatus of the present invention, it is possible to prevent the external additive from staying in the cleaning section of the latent image carrier using the toner of any one of the first to fourth aspects. Since the suppression is suppressed, occurrence of filming on the latent image carrier can be reduced. Further, since the life of the toner can be extended, the life of the image forming apparatus using the toner can be extended.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a conventional toner analysis method used for analyzing the state of adhesion between a mother particle of a toner and an external additive, which is an example of an embodiment of the toner according to the present invention.

FIG. 2 is a diagram illustrating equivalent particles and equivalent particle sizes used in the toner analysis method shown in FIG.

FIG. 3 is a diagram showing an analysis result by the toner analysis method shown in FIG. 1;

FIG. 4 is a view for explaining an approximate straight line used for constituting the toner of the present invention based on the analysis result shown in FIG. 3;

FIG. 5 is a diagram showing the results of an image forming test using the toner of the present invention and a toner other than the present invention.

6 is a diagram illustrating another example of the embodiment of the toner according to the present invention, and is a normal distribution diagram of the toner particle diameter obtained from the analysis result illustrated in FIG. 4;

7 is a diagram showing the results of an image forming test using the toner of the example shown in FIG. 6 and a toner other than this example.

8 is a diagram illustrating a normal distribution of the particle diameter of the external additive obtained from the analysis result illustrated in FIG. 4, illustrating still another example of the embodiment of the toner according to the present invention.

FIG. 9 is a diagram showing the results of an image forming test using the toner of the example shown in FIG. 8 and a toner other than this example.

FIG. 10 is a diagram schematically illustrating an example of a conventional image forming apparatus provided with a cleaning unit.

FIG. 11 is a diagram illustrating toner particles having an external additive adhered to mother particles.

FIG. 12 is a diagram illustrating filming that occurs when an image is formed by the image forming apparatus illustrated in FIG. 10 using a conventional toner.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Latent image carrier (OPC), 3, 4,
5, 6 developing device, 7 transferring device, 8 transferring material, 9 fixing device, 10 cleaning blade, 11 remaining toner box, 12 base particles (C), 13 external additive (Si)
O ₂ ), T: toner, T ′: residual toner

Claims (5)

[Claims] 1. A toner comprising a large number of base particles and a large number of external additives respectively attached to these base particles, wherein a distribution of a particle size of the external additive with respect to a particle size of the base particles is determined by a least square method. Wherein the slope of the approximate straight line (particle diameter of external additive / particle diameter of base particle) is set to 0.6 or less. 2. The toner according to claim 1, wherein the amount of the external additive released from the mother particles is set to 5% or less of the whole toner. 3. The method according to claim 1, wherein a value obtained by dividing an average particle diameter of the external additive adhering to the base particles by an average particle diameter of the entire external additive is set to be larger than 1. The toner according to claim 1, wherein 4. A toner comprising a large number of base particles and a large number of external additives respectively attached to the base particles, wherein the average particle diameter of the external additives attached to the base particles is determined by determining the average particle size of the external additives. A toner characterized in that a value obtained by dividing by an average particle diameter of the whole is larger than 1. 5. A latent image carrier on which an electrostatic latent image is formed, a developing device for developing the electrostatic latent image on the latent image carrier with toner, and transferring the developed image on the latent image carrier And a cleaning unit for cleaning residual toner remaining on the latent image carrier after the transfer, wherein the toner is the toner according to any one of claims 1 to 4. Image forming apparatus.