JP2704785B2 - Negatively chargeable non-magnetic toner and image forming method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negatively chargeable non-magnetic toner in electrophotography and an image forming method.

[Related Art] Conventionally, a corona discharger has been known as a charging unit in an electrophotographic apparatus or the like. However, corona dischargers have problems such as the need to apply a high voltage and the generation of a large amount of ozone.

Therefore, recently, the use of contact charging means without using a corona discharger has been studied. Specifically, a voltage is applied to a conductive roller serving as a charging member, and the roller is brought into contact with a photosensitive member serving as a member to be charged to charge the surface of the photosensitive member to a predetermined potential. If such a contact charging means is used, a lower voltage can be achieved as compared with a corona discharger,
Ozone generation is also reduced.

For example, in Japanese Patent Publication No. Sho 50-13661, it is possible to apply a low voltage when charging a photosensitive member by using a roller having a core covered with a dielectric material made of nylon or polyurethane rubber. However, in the above-mentioned conventional example, when the core metal is coated with nylon, there is no elasticity of rubber or the like, so that it is not possible to maintain sufficient contact with the member to be charged, resulting in poor charging. On the other hand, when the core metal is coated with polyurethane rubber, the softening agent impregnated in the rubber-based material oozes out, and when the photoreceptor is used as the charged body, the charging member contacts the photoreceptor when the photoreceptor stops at the contact portion. Stick. Alternatively, there has been a problem that the region causes image blur. Also, if the softening agent in the rubber material of the charging member oozes out and adheres to the surface of the photoreceptor, the resistance of the photoreceptor decreases, causing image deletion. The toner thus adhered to the surface of the charging member, and a filming phenomenon sometimes occurred. When a large amount of toner adheres to the surface of the charging member, the surface of the charging member is insulated, the charging ability of the charging member is lost, the charging of the surface of the photoreceptor becomes nonuniform, and the image is adversely affected.

On the other hand, when a developing process using a non-magnetic color toner having a negative charge is combined, various problems occur in addition.

In many cases, the toner does not contain a magnetic substance and does not contain a conductive substance such as carbon black from the viewpoint of color saturation. For this reason, there is no portion where the charge leaks, especially under low temperature and low humidity, and the charge tends to be excessively large as compared with the normal toner.

In addition, a full-color toner often uses a polyester resin as a binder resin depending on conditions such as fixing properties, color mixing properties, and transparency, but a toner made of a polyester resin is generally easily affected by temperature and humidity. Problems such as excessive charge under low humidity and insufficient charge under high humidity
Especially easy to occur.

Further, for the purpose of improving various image characteristics such as resolution, density uniformity and fog, external addition of silica fine powder to impart fluidity to toner is widely performed. The conventional silica fine powder has a large charge amount under low humidity, which further promotes the above problem.

In recent years, there has been a strong demand for higher image quality of copying machine images. On the other hand, high image quality has been achieved by reducing the particle size of the toner. However, even if the particle size of the toner is reduced, the surface area of the toner increases, so that the charge amount tends to be excessive.

As described above, when the charging is excessive, it is difficult to transfer the toner from the photoconductor, and the amount of the residual toner on the photoconductor increases. Also, because it is strongly charged and adheres to the photoconductor,
Cleaning failure is likely to occur. The toner that cannot be removed in these cleaning steps adheres to the charging member, causing a reduction in charging ability and filming of the photoconductor.

Further, when the particle diameter is small, the toner has many contact points with each other, so that the fluidity of the toner is deteriorated. Therefore, aggregation of toner occurs in the cleaning process, and cleaning failure occurs.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-described problems, and can sufficiently maintain contact between a charging member and a member to be charged, and can prevent sticking between the charging member and the member to be charged. It is used in an image forming method having a charging step of preventing and further preventing a plasticizer contained in the conductive rubber of the charging member from adhering to the member to be charged, so that a high-resolution and high-definition image can be obtained, and development, transfer and cleaning are performed. After passing through the process, there is very little toner remaining on the member to be charged, and toner that does not adhere to the surface of the charging member or the surface of the member to be charged,
An object of the present invention is to provide an image forming method including a developing step, a transferring step, and a cleaning step using the toner.

[Means and Actions for Solving the Problems] The present invention relates to an insulating negatively chargeable non-magnetic toner comprising at least a non-magnetic colorant-containing resin particle and a fluidity improver, wherein the non-magnetic colorant-containing The resin particles include a polyester-based binder resin having a diol component and a dicarboxylic acid component as main components, and a salt-forming compound represented by the following formula (I). Wherein at least one of the fluidity improvers is silica fine powder, and the silica fine powder is treated with a silane coupling agent having a positive triboelectrification site and a negative triboelectrification site, and is further treated with silicone oil. The present invention relates to a negatively chargeable non-magnetic toner which has been processed.

Further, the present invention includes a charging step of charging by contacting a charging member to which a voltage is applied from the outside with a member to be charged; a developing step of developing the member to be charged with toner; a transfer step; and a cleaning step. In the image forming method, the charging member has a conductive rubber layer, and a surface layer of a release coating on at least a portion outside the conductive rubber layer and in contact with the member to be charged. The toner is an insulating negatively-chargeable non-magnetic toner having at least non-magnetic colorant-containing resin particles and a fluidity improver, wherein the non-magnetic colorant-containing resin particles have a diol component as a component. A polyester-based binder resin containing a dicarboxylic acid component as a main component and a salt-forming compound represented by the following formula (I): Wherein at least one of the fluidity improvers is silica fine powder, and the silica fine powder is treated with a silane coupling agent having a positive triboelectrification site and a negative triboelectrification site, and is further treated with silicone oil. The present invention relates to an image forming method characterized by being processed.

The present inventor is a charging step of performing charging by bringing a charging member to which a voltage is applied from the outside into contact with a member to be charged, wherein the charging member is a conductive rubber layer and the conductive rubber layer is outside the conductive rubber layer. In adopting a charging step of applying a voltage from outside by contacting a charging member having a surface layer of a releasable film at least in a portion in contact with the member to be charged and applying a voltage from outside, a negative charge As a result of examining what is necessary for the non-magnetic toner to enable high resolution, high definition and high image quality, and not to have an excessive charge amount even under low humidity, and to have sufficient fluidity, It has been found that by adding a specific fluidity improver to a toner to which a specific substance having a specified resin for resin addition is added to the toner, and further defining the particle size distribution of the toner, it is possible to provide a toner that meets the above purpose. It is.

Hereinafter, the toner applicable to the developing step, the transferring step, and the cleaning step in the image forming method of the present invention will be described.

The present inventors have conducted intensive studies on the charging stability and charge-up prevention of a negatively chargeable nonmagnetic toner, and as a result, a salt-forming compound represented by the following formula (I) was obtained. And at least one of the flowability improvers is a silica fine powder, and the silica fine powder is treated with a silane coupling agent having a positive triboelectric charging site and a negative triboelectric charging site, and Negatively chargeable non-magnetic toner composed of a mixed form with silica fine powder treated with silicon oil is extremely excellent in charge stability in various environments,
They have found that they provide good images without fog.

The reason is that the charge-up due to excessive rubbing of the polyester resin as the binder resin with the carrier used in the present invention is neutralized by the positively chargeable salt forming compound. At this time, since the chlorinated compound has a weak positive charge property, the chlorinated compound has an effect of promoting the rise of the charge by rubbing with the salt forming compound without hindering the rise of the charge of the polyester resin. Further, after the charge of the polyester resin rises, a function of neutralizing excessive charge works, and therefore, the toner of the present invention has a rise in charge due to rubbing with a carrier, and a saturation charge level. In addition to being able to maintain good and stable in various environments, the cleaning properties are also good.

In the present invention, it is preferable that the content is 0.1 to 8 parts by weight based on 100 parts by weight of the binder resin in order to surely exhibit the performance and have a stable negative charging property.

As the salt-forming compound of the present invention, all known compounds can be used. It is optimal for a color toner because it is thermally stable and white.

Conventionally, the incorporation of the above compound in a toner is disclosed in Japanese Patent Publication No. 1-54694 or the like.However, these are included only for stabilizing the positive charging property, and the present invention and Is a completely different invention.

As the diol component of the polyester resin used in the present invention, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3
-Butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentene glycol, pentaerythritol diallyl ether, trimethylene glycol, 2-ethyl-1,3-hexane A diol, hydrogenated bisphenol A, or a bisphenol derivative represented by the following formula; (Wherein R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 2)
It is 10. ) And the like.

Further, as the dicarboxylic acid component, fumaric acid, maleic acid, citraconic acid, unsaturated dicarboxylic acids such as itaconic acid, or acid anhydrides thereof, succinic acid, adipic acid,
Examples include dicarboxylic acids such as sebacic acid and azoline acid, and acid anhydrides thereof, and aromatic dicarboxylic acids such as phthalic acid and terephthalic acid.

Particularly preferred polyester resins in the present invention are represented by the following formula: (Wherein R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 2)
It is 10. And a dicarboxylic acid component comprising a divalent carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof (for example, fumaric acid, maleic acid, maleic anhydride, phthalic acid) , Terephthalic acid, etc.) are more preferred because they have sharp melting properties.

As described above, by using the specific salt forming compound and the polyester resin in combination, the fixing property, the color mixing property, and the transparency required for the full-color toner are satisfied, and the charging by the friction with the carrier is performed. At the same time, the rise and the saturation charge level can be kept good and stable in various environments, and a toner having good cleaning characteristics can be obtained. However, for the purpose of improving various image characteristics such as resolution, density uniformity and fog, silica fine powder is usually externally added to the toner to impart fluidity to the toner. However, the conventional silica fine powder has a large amount of charge particularly under low humidity, and the problem that environmental stability is deteriorated due to external addition of the fine powder has occurred.

Until now, in order to obtain a toner having good environmental stability, the conventional idea was to suppress the water absorption of silica and to stabilize the triboelectric charge of silica itself. As an example of such a method, there is JP-A-49-42354 for treating silica with silicone oil, and JP-B-54-16219 for externally adding hydrophobic silica to a toner. Japanese Patent Application Laid-Open No. 56-123550 discloses a method of externally adding silica treated with a silane coupling agent to a toner. Thus, prior developments focused solely on treating agents and methods for hydrophobizing silica.

The present inventor believes that one of the biggest causes of the environmental instability of the toner is that the degree of environmental fluctuation of the triboelectric charge amount of the toner varies depending on the type of the toner carrier such as a carrier or a sleeve. This has had a considerable impact. In addition, even if the above polyester resin is used, the triboelectric charge of the silica-non-externally added toner varies depending on the environment. It is not enough that there is no environmental change, and it is necessary to change so as to cancel the change of the toner not externally added with silica. Further, silica having a high absolute value of the triboelectric charge is not preferable from the viewpoint of stabilizing the environment of the toner. Here, the silica having a high triboelectric charge means the triboelectric charge with the iron powder (EFV200 / 300 made by Nippon Iron Powder) measured by the blow-off method at a silica / iron powder ratio of 2: 100.
| -150 | μc / g or more. The present inventor has newly found the above-described knowledge, and has developed silica having low frictional chargeability and a frictional charge amount decreases as the humidity decreases. As a result of intensive studies, after treating the silica fine powder with a silane coupling agent having both a positive triboelectric charging site and a negative triboelectric charging site, and then further processing with silicon oil,
The present inventors have found that silica having a low triboelectric charging property and a lower triboelectric charge amount as the humidity becomes lower can be obtained, thereby completing the present invention.

As the silica fine powder of the present invention before the silica fine powder is treated with the silane coupling agent, any of dry process silica and wet process silica can be used. Processed silica is preferred.

The dry method referred to herein is a method for producing silica fine powder generated by vapor phase oxidation of a silicon halide derivative. For example, in a method utilizing the thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen-hydrogen, the basic reaction formula is as follows.

SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl In this manufacturing process, for example, by using another metal halide derivative such as aluminum chloride or titanium chloride together with a silicon halide derivative, a composite fine powder of silica and another metal oxide is obtained. It is also possible to include these.

On the other hand, as a method for producing the silica fine powder used in the present invention by a wet method, various conventionally known methods can be applied. For example, decomposition of sodium silicate with an acid, given by a general reaction formula (hereinafter, the reaction formula is abbreviated), Na ₂ O · XSiO ₂ + HCl + H ₂ O → SiO ₂ · nH ₂ O + NaCl, etc., and ammonium salts or alkali salts of silicon sodium , An alkaline earth metal silicate is produced from sodium silicate, then decomposed with acid to form silicic acid, a sodium silicate solution is converted to silicic acid with ion exchange resin, natural silicic acid or silicic acid There is a method using an acid salt.

Silica such as aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, zinc silicate, etc. can be applied to the silica fine powder here, in addition to anhydrous silicon dioxide (silica).

Among the above silica fine powders, those having a specific surface area of 30 m ² / g or more (particularly 50 to 400 m ² / g) measured by the BET method by nitrogen adsorption give good results.

Examples of the organic group that can be a positive triboelectrification site of the silane coupling agent include an amino group and a nitrogen-containing heterocyclic group. As the nitrogen-containing heterocyclic group, there are an unsaturated heterocyclic group and a saturated heterocyclic group, each of which can be applied.
Examples of the unsaturated heterocyclic group include the following.

Examples of the compound having a saturated heterocyclic group include the following.

Also, nitrogen-containing salt compounds such as quaternary ammonium salts and pyridinium salts can be exemplified. Further, phosphines, phosphonium salts and the like can be exemplified. However, an amino group and a nitrogen-containing heterocyclic group are preferable in consideration of easiness of synthesis and cost.

Various organic groups can be exemplified as the organic group that can serve as the negative triboelectrification site of the silane coupling agent.

For example, ordinary silane coupling agents whose organic groups do not have nitrogen or phosphorus are negatively triboelectrically chargeable. This is Si-
It is thought to be due to C-bonding, but it is very preferable to use this as a negative triboelectrification site. However, in this case, the negative triboelectrification due to the Si—C bond decreases with an increase in the number of carbon atoms of the hydrocarbon directly bonded to Si, and therefore, in the present invention, those having 3 or more hydrocarbons cannot be used. . Preferably, it has 2 or less carbon atoms.

In addition, an organic acid such as carboxylic acid and sulfonic acid, or an organo group having an acidic hydroxy group such as phenol can be used to positively provide a negative triboelectric charging site in the silane coupling agent.

Further, a halogen atom, a carbonyl group, a sulfonyl group,
By using a cyano group or the like, a negative triboelectric charging site can be provided in the silane coupling agent.

The silane coupling agent of the present invention can be synthesized by a conventionally known method. Basically, a hydrohalogenosilane or a hydroalkoxysilane and a compound having an alkene portion into which the above-mentioned positive triboelectric charging site (if necessary, a negative triboelectric charging site) is introduced are allowed to act in the presence of a catalyst such as a platinum-containing compound. It is not necessary to use a compound having an alkene moiety introduced with a negative triboelectric charge site when utilizing a Si-C bond as the negative triboelectric charge moiety, but otherwise has an alkene moiety having a positive triboelectric charge moiety introduced. Both the compound and the compound having an alkene moiety into which a negative triboelectric charging site is introduced need to be reacted with hydrohalogenosilane or hydroalkoxysilane. At this time, the order of the action of the compound having an alkene moiety into which the positive triboelectrically charged site is introduced may be either positive or negative, or may be simultaneously applied. Further, when one of the compounds having an alkene moiety into which a positive or negative triboelectric charge site is introduced is reacted with hydrohalogenosilane or hydroalkoxysilane,
After each of the two negative silane coupling agents is obtained, both may be acted to obtain the silane coupling agent according to the present invention. Alternatively, a halogenalkylalkoxysilane or a halogenoalkylhalogenosilane and a compound having the above-mentioned triboelectrically charged portion (if necessary, a negatively triboelectrically charged portion) may be allowed to act in the same manner as described above.

For example, in the case of diethylaminopropyltriethoxysilane, triethoxyhydrosilane and allyldiethylamine are allowed to act in the presence of a chloroplatinic acid catalyst, or chloropropyltriethoxysilane and dimethylamine are acted on, and then sodium methoxide is acted on. It can be obtained by purification.

Representative examples of the silane coupling agent of the present invention are shown below, but they do not limit the present invention in any way.

(1) Using a Si-C bond as a negative frictional charge site (1-3) H ₃ CNHCH ₂ Si (OCH ₃ ) ₃ (2) Those using a halogen, carbonyl, phenol, cyano group or the like as a negative frictionally charged part (3) Those using an organic carboxylic acid derivative as a negative triboelectric charging site (4) A product obtained by the action of a silane coupling agent having a negative triboelectric charging site and a silane coupling agent having a positive triboelectric charging site Silica treated with a silane coupling agent as described above improves the environmental stability of the toner and provides good fluidity and transferability. However, by further treating this silica with silicone oil, it becomes even more resistant to moisture. , Fluidity, and transferability can be improved. That is, the silicone oil treatment can improve the moisture resistance and improve the slipperiness of the silica, so that the fluidity of the toner can be increased and the transferability from the photosensitive drum can be further improved.

The silicone oil used in the present invention is generally represented by the following formula.

For example, dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil,
Chlorphenyl silicone oil, fluorine-modified silicone oil and the like can be mentioned. The silicone oil preferably has a viscosity at 25 ° C. of about 50 to 1000 centistokes. Silicon oil having a molecular weight that is too low may generate volatile components due to heat treatment or the like, and if the molecular weight is too high, the viscosity becomes too high and the processing operation becomes difficult.

Known technology is used for the method of silicon oil treatment,
For example, the silica fine powder treated with the above silane coupling agent and silicon oil may be directly mixed using a mixer such as a Henschel mixer, or a method of spraying silicon oil onto the silica fine powder, Alternatively, it may be prepared by dissolving or dispersing silicon oil in an appropriate solvent, mixing with silicon fine powder, and removing the solvent.

The degree of hydrophobicity of the silica fine powder in the present invention is desirably 90% or more (preferably 95% or more). If the degree of hydrophobicity is less than this, high quality images cannot be obtained due to moisture adsorption of the silica fine powder under high humidity.

The amount of silicon oil to be treated may be small because the silica fine powder is supposed to be hydrophobized in the previous stage, and the amount may be as small as 100 parts by weight of the silica fine powder after the treatment with the silane coupling agent.
/ 25 ± A / 30 (A: specific surface area of the silica fine powder) parts by weight, more preferably A / 25 ± A / 40. Here, the specific surface area of the silica fine powder is a value determined from N ₂ adsorption at the BET method. The reason for limiting the above treatment amount is that if the amount of the silicon oil treatment is too small, the same result will be obtained only with the silane coupling agent treatment, and further improvement cannot be achieved. Also, if too much silicon oil is processed,
Agglomerates of the silica fine powder are easily formed, and
Extremely free silicone oil is produced,
When applied to a developer, drawbacks such as the inability to improve fluidity arise.

The amount of the silica fine powder used in the present invention is 0.01 to 5%, preferably 0.05 to 2%, based on the weight of the toner.
It is. Further, the silicas used in the present invention may be used together or some known silicas may be used in combination.

In producing the toner of the present invention, the constituent materials are kneaded well by a heat kneading machine such as a hot roll, a kneader, an extruder and the like, and then obtained by mechanical pulverization and classification, or magnetic powder or the like in a binder resin solution. A polymerized toner obtained by dispersing the above material and spray-drying, or by mixing a predetermined material with a monomer to constitute the binder resin and then polymerizing this emulsion suspension to obtain a toner Each method such as a manufacturing method can be applied.

Next, a preferred particle size distribution of the negatively chargeable non-magnetic toner of the present invention will be described. In the following description regarding the particle size distribution of the toner, “non-magnetic colorant-containing resin particles” are referred to as “toner particles”.

In the present invention, the negatively-chargeable non-magnetic toner has a volume average particle diameter in the range of 6 to 10 μm, contains 15 to 40% by number of toner particles having a particle diameter of 5 μm or less, and has a volume average particle diameter of 12.7 to 16.0 μm.
0.1 to 5.0% by volume of toner particles having a particle size of m
A toner particle having a particle size of 6.35 to 10.1 μm containing toner particles having a particle size of 16 μm or more and 1.0% by volume or less is represented by the following formula: The effect is more pronounced when having a particle size distribution that satisfies

The toner having the above particle size distribution can faithfully reproduce a latent image formed on a photoreceptor, and is excellent in reproducibility of a minute dot latent image such as a halftone dot and a digital image. An image excellent in gradation and resolution of the part is provided. Furthermore, high image quality can be maintained even when copying or printing out is continued, and even in the case of high density images, good development can be performed with less toner consumption than conventional non-magnetic toner. It also has advantages in terms of performance and miniaturization of the copier or printer body.

The reason why such an effect is obtained in the toner of the present invention is not necessarily clear, but is presumed as follows.

Conventionally, toner particles having a particle size of 5 μm or less
It is difficult to control the charge amount, impair the fluidity of the toner, and must be positively reduced as a component that scatters the toner and contaminates the machine, as well as a component that causes image fogging. Was thought. However, according to the study of the present inventors, it has been found that toner particles of about 5 μm are essential components for forming high-quality images.

For example, using a two-component developer having a non-magnetic toner and a carrier having a particle size distribution ranging from 0.5 μm to 30 μm, the surface potential on the photoreceptor is changed, and a large development potential contrast in which many toner particles are easily developed. From halftone to halftones, and then to latent images of small dots where only a few toner particles are developed. Was collected and the toner particle distribution was measured.
It was found that there were many toner particles having a particle size of m or less, especially about 5 μm on the latent image of fine dots. That is,
When the toner particles having a particle size of about 5 μm are smoothly supplied to the development of the latent image on the photoreceptor, the toner is faithful to the latent image, and an image with excellent reproducibility can be obtained without protruding from the latent image. It is.

Further, toner particles of 12.7 μm to 16.0 μm are related to the necessity of the existence of toner particles having a particle size of about 5 μm.
Non-magnetic toner particles having a particle size of μm or less certainly have the ability to faithfully reproduce a latent image of fine dots, but themselves have considerably high cohesiveness, which may impair the fluidity of the toner.

The present inventor has further improved the fluidity by adding the above-mentioned silica fine powder for the purpose of improving the fluidity, but by itself, image density, toner scattering, fog, etc. It was confirmed that the conditions to be satisfied were very narrow. Therefore, the present inventor further studied the particle size distribution of the toner and found that the toner particles having a particle size of 5 μm or less contained 15 to 40% by number and 12.7 to
It has been found that the flowability can be further improved and high image quality can be achieved by containing 0.1 to 5.0% by volume of 16.0 μm toner particles. That is, it is considered that the toner particles in the range of 12.7 to 16.0 μm have a moderately controlled fluidity with respect to the toner particles of 5 μm or less, and as a result, even when copying or printing out is continued with high accuracy. A sharp image with excellent resolution and gradation is provided.

Further, for the toner particles of 6.35 to 10.1 μm, between the volume% (V), the number% (N) and the volume average particle size (v), It is further desirable that the toner of the present invention satisfies the following relationship.

The present inventor has found out that there is a state of existence of a particle size distribution which is most suitable for achieving the object as shown by the above formula, while examining the state of the particle size distribution and the development characteristics.

That is, when the particle size distribution is adjusted by general air classification, a large value of the above equation means that toner particles of about 5 μm that faithfully reproduce a minute dot latent image increase and the above value is small. Conversely indicates that toner particles of about 5 μm are reduced.

Therefore, when v is in the range of 6 to 10 μm and the above relational expression is further satisfied, good toner fluidity and faithful latent image reproducibility are achieved.

For toner particles having a particle size of 16 μm or more, 1.
It is preferable that the content is 0 volume% or less and the amount is as small as possible.

The configuration of the present invention will be described in more detail. 5μ
The number of toner particles having a particle size of m or less is preferably 15 to 40% by number of the total number of particles, and more preferably 20 to 35% by number.
When the number of toner particles having a particle size of 5 μm or less is 15% by number or less, the amount of non-magnetic toner particles effective for high image quality is small.
As the toner is used by continuing to copy or print out, the effective toner particle component decreases,
The balance of the particle size distribution of the toner deteriorates, and the image quality gradually decreases. When the content is more than 40% by number, toner particles are likely to aggregate with each other, resulting in a toner mass having an original particle size or more, resulting in rough image quality and reduced resolution.
Alternatively, the density difference between the edge portion and the inside of the latent image increases, and the image tends to be slightly hollow.

The particles in the range of 12.7 to 16.0 μm are 0.1 to 5.0% by volume.
And preferably 0.2 to 3.0% by volume.
When the content is more than 5.0% by volume, the image quality is deteriorated, and the development is performed more than necessary, that is, the toner is excessively applied, which causes an increase in toner consumption. On the other hand, when the content is less than 0.1% by volume, the image density is lowered due to the decrease in fluidity.

Further, the content of toner particles having a particle size of 16 μm or more is preferably 1.0% by volume or less, more preferably 0.6% by volume or less. The irregular contact between the photoreceptor and the transfer paper through the toner layer is irregular due to the presence of 16 μm coarse toner particles protruding from the thin layer surface of the toner particles developed on the photoreceptor. As a result, a change in transfer conditions is caused, which is likely to cause a transfer failure image. Further, the volume average diameter of the toner is 6 to 10 μm, preferably 7 to 9 μm, and this value cannot be considered separately from each of the above-described components.
When the volume average particle diameter is less than 6 μm, in applications having a high image area ratio such as a graphic image, there is a problem that the amount of applied toner on the transfer paper is small and the image density is low.
This is considered to be due to the same reason as described above for lowering the density inside the edge portion of the latent image.
If the volume average particle diameter is 10 μm or more, the resolution is not good, and if the use is continued at the beginning of copying, the image quality tends to deteriorate.

As described above, by using this toner, a high-resolution, high-definition, high-quality copy image can be obtained, and the charge amount can be prevented from becoming excessive even under low humidity. As a result, the transfer efficiency is increased, the residual toner on the photoreceptor is reduced, and the adhesive force between the residual toner and the photoreceptor is reduced, so that cleaning failure and leakage from the cleaner can be prevented. In addition, since sufficient fluidity is obtained, aggregation in the cleaner is small, and poor cleaning due to toner aggregation can be prevented. Further, since a sufficient charge amount can be secured even under low humidity, scattering and fogging do not occur.

As the coloring agent, known dyes and pigments, for example, phthalocyanine blue, induslen blue, peacock blue, permanent red, lake red, rhodamine lake, Hansa yellow, permanent yellow, benzidine yellow and the like can be used widely. The content thereof is 12 parts by weight or less, preferably 0.5 to 9 parts by weight, based on 100 parts by weight of the binder resin so as to be sensitive to the light transmittance of the OHP film.

The toner according to the present invention may contain a charge control agent for stabilizing the charge characteristics. At that time, a colorless or light-colored charge control agent that does not affect the color tone of the toner is preferable.
In the present invention, when the present invention is used as a negatively chargeable non-magnetic toner, the present invention becomes more effective. In this case, as a negative charge control agent, for example, a metal complex of an alkyl-substituted salicylic acid (for example, di-tert-butylsalicylic acid) Organometallic complexes such as chromium complexes or zinc complexes). When the negative charge control agent is added to the toner, it is added in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the binder resin.

Although the toner of the present invention can be applied to both the one-component developing method and the two-component developing method, an electrically insulating resin is used as a coating resin for a carrier core material in a carrier when used as a two-component developer. It is appropriately selected depending on the material and the carrier core material. In the present invention, in order to improve the adhesiveness with the carrier core material surface, at least one monomer selected from acrylic acid (or its ester) monomer and methacrylic acid (or its ester) monomer is used. It is necessary to contain. In particular, when a polyester resin particle having a high negative chargeability is used as the toner material, it is preferable to further form a copolymer with a styrene-based monomer for the purpose of stabilizing the charge. The content is preferably set to 5 to 70% by weight.

The average molecular weight of the copolymer, the number average molecular weight is 10,000 in consideration of the uniformity of the coating of the carrier core material surface, the coating strength.
335,000, preferably 17,000-24,000, and a weight average molecular weight of 25,000-100,000, preferably 49,000-55,000.

As the monomer for the coating resin of the carrier core material that can be used in the present invention, examples of the styrene-based monomer include a styrene monomer, a chlorostyrene monomer, an α-methylstyrene monomer, and a styrene-chlorostyrene monomer. For example, acrylate monomers (methyl acrylate monomer, ethyl acrylate monomer, butyl acrylate monomer,
Octyl acrylate monomer, phenyl acrylate monomer, 2-ethylhexyl acrylate monomer) and the like, and methacrylate ester monomers (methyl methacrylate monomer, ethyl methacrylate monomer, butyl methacrylate monomer, phenyl methacrylate monomer).

As the magnetic particles used in the present invention, for example, metals such as iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earth and the like, and their alloys or oxides, whose surface is oxidized or not oxidized, can be used. In addition, there is no particular limitation on the manufacturing method.

Next, a specific example of a contact charging step applicable to the image forming method will be described.

The charging device in the present invention is, for example, as shown in FIG. Reference numeral 3 denotes a photosensitive drum which is a member to be charged, and rotates in the direction of the arrow. Reference numeral 4 denotes a charging roller which is a charging member brought into contact with the photosensitive drum 3 at a predetermined pressure.
E is a power supply unit that applies a voltage to the charging roller 4 and supplies a predetermined voltage to the metal core 4 a of the charging roller 4. In FIG. 2, E indicates a DC voltage, but may be obtained by superimposing an AC voltage on a DC voltage.

In the present invention, the conductive rubber layer 4b is provided on the metal cored bar 4a, and the surface layer 4c which is a release coating is provided on the peripheral surface. The reason is that a softening agent from the conductive rubber does not exude to a portion which comes into contact with the photoreceptor which is a charged member by providing a release coating outside the conductive rubber layer. Therefore, when the softener adheres to the photoreceptor, image flow due to lowering of the resistance of the photoreceptor and a decrease in charging ability due to filming of residual toner on the photoreceptor can be prevented, and a decrease in charging efficiency can be suppressed.

Furthermore, by using a conductive rubber layer for the charging roller, sufficient contact between the charging roller and the photoconductor can be maintained, and no charging failure occurs.

In the present invention, a charging device as shown in FIG. 2 can be used. Here, a blade-shaped contact charging member is used, but a metal supporting member 4 ′ to which a voltage is also supplied.
By supporting the conductive rubber 4'b with a, and providing a surface layer which is a release coating at a contact portion with the photosensitive drum 3, the same operation and effect as in the above example can be obtained.

In the above-described example, a roller-shaped or blade-shaped charging member is used. However, the present invention is not limited to this, and the present invention can be applied to other shapes.

In the above-described example, the charging member is composed of the conductive rubber layer and the release film. However, the invention is not limited thereto. It is preferable to form a layer, for example, a hydrin rubber layer having small environmental fluctuation.

Nylon resins PVDF (polyvinylidene fluoride) and PVDC (polyvinylidene chloride) can be used for the release coating. Further, as the photoconductor, OPC, amorphous silicon, selenium, ZnO, or the like can be used. In particular, when amorphous silicon is used for the photoconductor, compared to the case where other materials are used, even if the softening agent of the conductive rubber layer adheres to the photoconductor even to a small extent, the image flow becomes severe, so The effect of the insulating coating is great.
Further, the charging device of the present invention can be used for transfer.

Hereinafter, measurement methods (1) to (3) relating to the characteristic values of the toner used in the present invention will be described.

(1) Particle size distribution measurement: Coulter counter TA-II type (manufactured by Coulter) was used as the measuring device, and an interface (manufactured by Nikkaki) for outputting the number distribution and volume distribution and a CX-1 personal computer (manufactured by Canon) were used. A 1% aqueous solution of NaCl is prepared using primary sodium chloride as an electrolyte.

As a measurement method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the aqueous electrolytic solution, and 0.5 to 50 mg of a measurement sample is further added.

The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the Coulter Counter TA-II was used, using a 100 μm aperture as an aperture.
By measuring the particle size distribution of the particles of 2 to 40 μm, the volume average distribution,
Find the number average distribution.

From the obtained volume average distribution and number average distribution, respective values of the volume average particle size, the number average distribution of 5.04 μm or less, and the volume average distribution of 16.0 μm or more are obtained.

(2) Measurement of triboelectric charge: FIG. 3 is an explanatory view of a triboelectric charge measuring device. First, a mixture of particles to be measured and magnetic particles used as a developer is prepared. The mixing ratio is 5 parts by weight for 95 parts by weight of magnetic particles in the case of toner and colorant-containing fine particles, and 2 parts by weight in 98 parts by weight of magnetic particles in the case of a fluidity imparting agent. .

The particles to be measured and the magnetic particles are placed in a measurement environment and left for 12 hours or more, then put into a polyethylene bottle, and sufficiently mixed and stirred.

Next, a mixture of particles and magnetic particles whose triboelectric charge amount is to be measured is placed in a metal measuring container 32 having a conductive screen 33 of 500 mesh (which can be changed to a size that does not allow magnetic particles to pass through) at the bottom. Then, a metal lid 34 is provided. At this time, the weight of the entire measurement container 32 is weighed and set as W ₁ (g). Next, in the suction device 31 (at least a portion in contact with the measurement container 32 is an insulator), the pressure of the vacuum gauge 35 is adjusted to 250 mmAq by adjusting the air volume control valve 36 by suctioning from the suction port 37. In this state, suction is performed sufficiently (about 2 minutes) to remove the toner by suction. At this time, the potential of the electrometer 39 is set to V (volt). Where 38
Is a capacitor and the capacity is C (μF). Also,
The weight of the whole measuring container after suction is weighed and is defined as W ₂ (g). This triboelectric charge amount T (μC / g) is calculated as in the following equation.

(3) Hydrophobicity measurement: 100 ml of pure water and 1 g of a sample are placed in a tightly closed container and shaken with a shaker for 10 minutes. After shaking, the silica powder layer and the aqueous layer were separated, and the aqueous layer was collected.The transmittance was measured at a wavelength of 500 mm with reference to pure water of a blank containing no silica fine powder, and the transmittance was measured. Is defined as the degree of hydrophobicity of the treated silica.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples. A charging device and a toner were prepared.

Charging device: The configuration shown in FIG. 1, and the outer diameter of the charging roller 4 is 12 mmφ
The conductive rubber layer 4b is EPDM, and the surface layer 4c is 10 μm thick.
Was used. The hardness of the charging roller 4 is 5
4.5 ゜ (ASKER-C).

Charging device: A charging roller having the same configuration as that of Example 1 but having no surface layer 4c was used. Others are the same as the charging device.

Charging device: The configuration is the same as that of Example 1, except that the surface layer 4c is made of PVDF resin.

After sufficient premixing with a Henschel mixer,
The mixture was melt-kneaded at least twice with a three-roll mill, cooled, and coarsely ground to a particle size of about 1 to 2 mm using a hammer mill. Next, it was pulverized by a pulverizer using an air jet method. Further, the obtained finely pulverized product was classified to obtain colorant-containing resin particles.

100 parts by weight of the above colorant-containing resin particles were treated with 20 parts of the silane coupling agent shown in Compound Example (1-1) per 100 parts by weight of silica fine powder Aerosil 200 (manufactured by Aerosil Co., Ltd.) (temperature: 150 ° C.) After 2 hours), 10 parts of dimethyl silicone oil KF-96 100cs (manufactured by Shin-Etsu Chemical Co., Ltd.) was diluted with a solvent, and then dried. To obtain a cyan toner. The particle size distribution of this toner was as follows.

Toner: A toner was prepared in the same manner as the toner except that the salt forming compound II of the present invention was used.

Toner: A toner was prepared in the same manner as the toner except that the salt forming compound I of the present invention was not used.

Toner: A toner was prepared in the same manner as the toner except that a negatively chargeable silica fine powder treated with dimethyldichlorosilane was used as a fluidity improver.

Except for Example 4, for these toners to 6 parts,
Cu-Zn-Fe-based ferrite particles 94 surface-coated with a styrene-acrylic acid-ethyl methacrylate 2-ethylhexyl copolymer 94
Parts were mixed to form a developer.

Example 1 The charging device of a commercially available copying machine (CLC-500, manufactured by Canon) was modified to take the configuration shown below, and the contact pressure on the photoconductor was reduced to 50 g /
cm, and the applied voltage is set so that the development contrast is 290V at 23 ° C / 65%, 350V at 20 ° C / 10%, 250V at 30 ° C / 80%, and the developer using toner is injected. , And performed image drawing. As a result, the charging roller after the endurance was hardly stained, and no filming occurred on the photoreceptor. Further, even after the endurance, the decrease in the charging efficiency was very small as compared with before the endurance. During endurance, high-quality images with sufficient image density of 1.40 to 1.55 and no fog were obtained in each environment.

Example 2 A printing durability test was conducted in the same manner as in Example 1 using the charging step and the developer. As a result, the reduction in charging efficiency was small, and the charging roller was not stained and the photoconductor was not filmed.

Example 3 A printing durability test similar to that in Example 1 was performed using the above charging step and developer, and a high quality image having a sufficient image density was obtained. Also, no contamination of the charging roller and no filming of the photoreceptor occurred.

Example 4 The charging device of a commercially available copying machine (CLC-500, manufactured by Canon) was modified to take the configuration shown in Fig. 4, and the developing device was modified so as to have the configuration shown in Fig. 4 with the following conditions. Was done. That is, in FIG. 4, reference numeral 42 denotes a sleeve formed by coating a phenol resin obtained by dispersing 40 parts by weight of molybdenum disulfide on the surface of an aluminum cylinder (coat layer thickness: 13 μm).
m). 44 is a urethane sponge roller.
The developer application blade 45 is in contact with the sleeve 42 at a linear pressure of 80 g / cm. The gap between the developer carrier and the latent image holder was maintained at 250 μm, and the thickness of the toner layer was regulated at 50 μm. 20
The durability test of 6000 sheets was performed in each environment of ℃ / 10%, 23 ℃ / 60%, 30 ℃ / 80%, and the image density was 1.40 ~ 1.55 in each environment.
A stable and clear image without fog was obtained. Also,
After the durability test, the charging roller was hardly stained. Further, no filming occurred on the photoreceptor, and no reduction in charging efficiency was observed.

Comparative Example 1 Using the above charging step and the developer, the same printing durability test as in Example 1 was performed. After the endurance, the charging efficiency is significantly reduced after the endurance. The charging roller was slightly dirty, and filming occurred on the photoreceptor. This is considered to be due to the softening agent for the rubber of the charging roller.

Comparative Example 2 Using the above charging step and the developer, the same printing durability test as in Example 1 was performed. The charging roller was dirty, and filming also occurred on the photoreceptor. Further, under low temperature and low humidity, the image density was remarkably reduced as compared with Example 1 as printing was performed.

Comparative Example 3 As a result of performing the same printing durability test as in Example 1 using the above-described charging step and the developer, contamination of the charging roller and filming on the photosensitive member occurred, and image deterioration occurred.

[Effects of the Invention] According to the present invention, the contact between the charging member and the member to be charged can be sufficiently maintained, the sticking between the charging member and the member to be charged can be prevented, and the contamination of the charging member and the member to be charged can be prevented. In addition to preventing filming, it has made it possible to obtain high-resolution, high-definition images.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a charging roller of the present invention,
FIG. 2 is an explanatory view schematically showing a blade according to another embodiment of the present invention, FIG. 3 is an explanatory view of a triboelectric charge measuring device, and FIG. 4 is an explanatory view of a developing device used in the fourth embodiment. It is. 3: Photoconductor drum, 4, 4 ': Charging member E: Power supply, 31: Suction machine 32: Measuring container, 33: Conductive screen 34: Lid, 35: Vacuum gauge 36: Air flow control valve, 37: Suction port 38 : Capacitor, 41: Development holder 42: Sleeve, 43: Developer 44: Sponge roller 45: Developer application blade 46: Power supply

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location G03G 9/08 371

Claims (4)

(57) [Claims] 1. An insulating negatively chargeable non-magnetic toner comprising at least non-magnetic colorant-containing resin particles and a fluidity improver, wherein the non-magnetic colorant-containing resin particles are composed of a diol component and a diol component. A polyester-based binder resin containing a dicarboxylic acid component as a main component and a salt-forming compound represented by the following formula (I): Wherein at least one of the fluidity improvers is silica fine powder, and the silica fine powder is treated with a silane coupling agent having a positive triboelectrification site and a negative triboelectrification site, and is further treated with silicone oil. A negatively chargeable non-magnetic toner, which has been treated. 2. The negatively chargeable non-magnetic toner has a volume average particle diameter in the range of 6 to 10 μm and contains 15 to 40% by number of non-magnetic colorant-containing resin particles having a particle diameter of 5 μm or less. , 1
0.1 to 5.0% by volume of non-magnetic colorant-containing resin particles having a particle size of 2.7 to 16.0 μm, and 1.0% by volume or less of non-magnetic colorant-containing resin particles having a particle size of 16 μm or more; Non-magnetic colorant-containing resin particles having a particle size of ~ 10. 2. The negatively chargeable non-magnetic toner according to claim 1, wherein the following formula is satisfied. 3. An image having a charging step of charging a member to be charged by contacting a charging member to which an external voltage is applied, a developing step of developing the charged body with toner, a transferring step, and a cleaning step. In the forming method, the charging member has a conductive rubber layer, and a surface layer of a release coating on at least a portion outside the conductive rubber layer and in contact with the member to be charged, The toner is an insulating negatively chargeable non-magnetic toner having at least non-magnetic colorant-containing resin particles and a fluidity improver, wherein the non-magnetic colorant-containing resin particles have a diol component and a dicarboxylic acid component. A polyester-based binder resin containing an acid component as a main component and a salt-forming compound represented by the following formula (I): Wherein at least one of the fluidity improvers is silica fine powder, and the silica fine powder is treated with a silane coupling agent having a positive triboelectrification site and a negative triboelectrification site, and is further treated with silicone oil. An image forming method characterized by being processed. 4. The negatively chargeable non-magnetic toner according to claim 3, wherein the volume average particle diameter is in the range of 6 to 10 μm.
2. The image forming method according to 1.,