JPH0876405A - Color toner for nonmagnetic unitary development - Google Patents

Abstract

PURPOSE: To provide a color toner that is able to stabilize a toner's charged value on a developing roller of this color toner, securing a sufficient developing quantity to an latent image holder at the elapse, and to prevent any texture fogging on the image in addition. CONSTITUTION: On the surface of base coloring grains of 5 to 10μm in volume mean grain size consisting of at least a colorant, binder resin and an electrostatic charge control agent, 1) at least fine powder of hydrophobic silica is made up of being mixed and covered at the rate of 0.3 to 1.0 pt.wt. to 100 pt.wt. of the base coloring grains, 2) when the absolute value of charged value in the base coloring grains is set to Q1 μC/g as well as the adsolute value of charged value in a toner grain to Q2 μC/g, respectively, relations of 0.8<Q1 /Q2 <1.2 are materialized and 3) when a coherent degree of the base coloring grains is set to G1 % as well as that of the toner grain to G2 %, respectively, relations of G2 %<G1 %<3×G2 % are materialized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color toner used for non-magnetic one-component development in electrophotography, electrostatic photography and the like.

[0002]

2. Description of the Related Art In recent years, as an example of developing a latent image by an electrophotographic method, an electrostatic recording method, etc., a developing magnet roller having a sleeve internally provided with a magnetic field generating means and a magnetic one-component toner are used. The methods used in combination are popular. However, the magnetic toner has a drawback that it is not suitable for color recording because the magnetic substance mixed therein is black. The electrostatic latent image developing operation using the magnetic one-component toner is performed by rotating the sleeve, rotating the internal magnet, or both. Generally, the magnet is rotated to perform the development. At this time, the moving speed of the magnetic toner is set to 2 to 4 times the latent image so that the pitch of the magnetic pole does not appear in the image, and the sleeve or the magnet rotates. Select a speed. However, in order to ensure sufficient uniformity of image density, the rotation of the magnet must be made considerably fast, and a powerful motor is required to drive it, which naturally leads to an increase in the size of the device. become.

In order to avoid such inconvenience, a one-component developer having no magnetism is disclosed in Japanese Examined Patent Publication No. 41-9475. Then, here, it is considered to apply a toner member having a thin toner layer on the surface thereof in the vicinity of the latent image forming body so as to fly the toner only to the latent image in a non-contact relationship. In this document, the retention of toner is achieved by suctioning and adsorbing the toner onto a web having an appropriate adhesive property or a film sheet which has been previously charged. However, in this method, the length of the sheet and the web is limited, and it is not suitable for continuous copying and printing.

As a means for solving such a problem, a method is disclosed in Japanese Patent Laid-Open No. 229065/1985, in which a developer carrier is made endless and development is performed by flying a non-magnetic one-component toner, and the development is transferred to a recording paper. It is disclosed. In this example, a uniformizing member is brought into contact with a developing roller to form a thin layer of toner, and a developing bias such as DC superimposing AC is applied to develop the latent image. JP-A-50-3053
Japanese Laid-Open Patent Publication No. 7-76 discloses a method for increasing the image density by the pulse bias method. Furthermore, JP-A-47
In Japanese Patent Laid-Open No. 12635 and Japanese Patent Laid-Open No. 50-10143, there is shown a structure of a developer carrier having a minute pattern of an insulator portion (dielectric portion) and a conductor portion on its surface. These are for forming toner peaks and valleys according to the minute pattern by using a minute electric field so as to adhere toner corresponding to the potential level of the latent image, and are aimed at multilayering. Regardless of which method is used, the toner characteristics on the developing roller are important because the amount of developer to the latent image carrier changes depending on how the toner is applied to the developing roller. .

Further, various non-magnetic one-component developing methods which do not use a carrier have been proposed in Japanese Patent Laid-Open No. 58-116559, etc., but in a color toner requiring a low melting point and a sharp melt, the fluidity is improved. When an external additive for the purpose of adhering to the toner surface, the external additive is subjected to a mechanical hazard such as when the toner passes through the developing roller and the developer coating blade by using the developing unit,
By being embedded in the toner surface, the toner characteristics on the developing roller are likely to change. Further, the use of color toners for non-magnetic one-component development is not well known for the above reason, and a fluidity improver externally added for the purpose of improving the fluidity of the toner is used in the developing unit. Due to the change in toner characteristics due to being embedded in the toner surface due to the mechanical hazard of, the amount of toner charge on the developing roller is stabilized over time, and the amount of development on the latent image carrier is sufficient. Does not exist, and there is no means for preventing background fog on the image.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and its purpose is to:
It is possible to stabilize the charge amount of the color toner on the developing roller of the color toner used in the non-magnetic one-component developing method, to secure a sufficient amount of development to the latent image carrier over time, and to prevent background fog on the image. To provide color toner.

[0007]

According to the present invention, a supply member for supplying toner onto a developing roller and a developer coating blade provided on the downstream side of the supply member are provided on the developing roller. Used in a method of applying negative pressure multilayered toner to the developing roller in multiple layers under pressure contact and reversal developing the negative polarity color toner in contact or non-contact with a latent image holding member composed of an organic photosensitive layer facing the developing roller. A color toner, wherein at least fine particles of hydrophobic silica are present on the surface of base colored particles having a volume average particle diameter of 5 to 10 μm and containing at least a colorant, a binder resin and a charge control agent, based on 100 parts by weight of the base colored particles. .3～1.0 made is mixed coated at a ratio of parts by weight, yet maternal absolute value charge amount of the colored particles Q ₁ [mu] C / g, the absolute value of the charge amount of the toner particles Q ₂ [mu] C / g When _{you, 0.8 <Q 1 / Q 2} <
The relationship of 1.2 holds, and when the aggregation degree of the mother colored particles is G ₁ % and the aggregation degree of the toner particles is G ₂ %, G
There is provided a non-magnetic one-component developing color toner characterized in that a relationship of ₂ % <G ₁ % <3 × G ₂ % is established.

Further, according to the present invention, in a preferred embodiment, there is provided the non-magnetic one-component developing color toner in which the charge control agent is a metal salt of a salicylic acid derivative, and the fine powder of the hydrophobic silica is hydrophobic. The above-mentioned non-magnetic one-component developing color toner having a degree of conversion of 50% or more is provided.

The present invention will be described in more detail below. In the electrophotographic method, the non-magnetic one-component developing method is advantageous in reducing the size and cost of the developing method for obtaining a color image. Further, as the developing means, a so-called contact developing method in which a latent image holding member and a developing roller are brought into contact with each other to perform development, and the toner transferred to the latent image holding member is transferred to plain paper to obtain an image, a so-called contact developing method The holding body and the developing roller are not in contact with each other, and the toner is caused to fly from the developing roller to the latent image holding body according to the latent image to perform development, and the toner image transferred to the latent image holding body is transferred to plain paper or the like. There is a so-called non-contact developing method for obtaining an image.

These contact and non-contact developing systems have their own advantages and disadvantages. That is, in the case of the contact developing system, high toner developing ability is imparted, but if the thickness of the toner layer on the developing roller is not uniform, image unevenness easily occurs on the image. Further, in the case of the non-contact developing method, even if the thickness of the toner layer on the developing roller is slightly non-uniform, the adverse effect on the image is small, but it is difficult to obtain a high developing ability, and it is difficult to obtain an AC electric field. Development bias conditions are required. The present invention can be applied to any of the above-mentioned developing methods, and the basic characteristic relating to the above-mentioned developing is that the toner characteristic on the developing roller is important for any developing method.

On the other hand, it is advantageous in terms of safety to use a latent image carrier having an organic photosensitive layer.
In consideration of the fact that an organic photoconductor is generally negatively charged, that digital processing is performed on a color image, and that it is easy to perform optical writing in a portion corresponding to an image portion in terms of processing, It is practically advantageous to perform reversal development with toner. Therefore, the present invention is also applicable to so-called full-color development. However, it is also applied to black development in color development using so-called yellow, magenta, cyan, and black as basic colors.

In the present invention, the linear velocity ratio between the developing roller coated with multi-layered color toner and the latent image carrier is 2: 1 to.
It is preferably 1: 1. That is, the ideal toner development amount for the latent image carrier is an appropriate image density, background fog,
Considering the transfer rate to plain paper, etc., 0.8 to 2.0
It is considered appropriate to use mg / cm ² . In order to obtain such a high toner development amount by the non-magnetic one-component developing method, it is necessary to apply toner in multiple layers on the developing roller and to increase the rotation speed of the developing roller as compared with the latent image carrier. . However, when the linear velocity of the developing roller is extremely increased, the toner tends to be shifted toward the trailing edge of the image and the toner is easily scattered from the developing roller. Therefore, it is suitable that the linear velocity ratio between the developing roller and the latent image carrier is about 2: 1 to 1: 1 and preferably about 1.5: 1 to 1: 1.

In order to stably obtain the high toner development amount as described above even after long-term use (printing), the toner application amount and the charge amount on the developing roller are not significantly changed even after long-term use. Will be needed. In particular, when new toner is additionally replenished after the toner has been developed and consumed, the toner remaining in the developing unit and the additionally replenished toner are mixed, and when the charging ability of both toners is different, Toner with weak charging ability is developed on the non-image area,
So-called background fog may occur.

As a result of analysis by the present inventors regarding the cause of this, the toner remaining in the developing unit with respect to the additionally supplied toner shows various mechanical hazards (developing roller and toner supply member, etc.) in the residual unit. The toner characteristics change when the toner passes between the developer coating blades), and the fluidity improver added and adhered to the toner surface for the purpose of improving the fluidity is embedded in the toner surface. It became clear that the impact was large. That is, the charging property and the fluidity of the toner are changed by embedding the fluidity improver on the surface of the toner. In particular, in color toners, in order to obtain sufficient fixability and transparency, it is necessary to use a resin having a lower softening point than the binder resin used for toners used in ordinary black and white copying machines. Furthermore, the fluidity improver and the like are easily embedded in the toner surface. In order to improve this point,
It is difficult to use a resin in which the fluidity improver is hard to be embedded, and it is necessary to find a toner structure in which the characteristics of the toner hardly change even when the fluidity improver is embedded.

As a result of intensive investigations by the present inventors, the use of the toner having the constitution of the present invention makes it difficult for the characteristics of the toner and the toner to change even if the fluidity improver is embedded therein, and satisfies the above-mentioned necessary items. It turned out to be. Less than,
The toner of the present invention will be described in detail.

The toner of the present invention has a volume average particle size of 5 to 5 comprising at least a colorant, a binder resin and a charge control agent.
On the surface of the base colored particles having a size of 10 μm, at least 0.3 parts of fine powder of hydrophobic silica is added to 100 parts by weight of the base colored particles.
One of the requirements is that they are mixed and coated at a ratio of 1.0 part by weight. The volume average particle diameter of the mother colored particles has a great influence on the toner coating amount on the developing roller in the developing process according to the present invention, and when toners having different volume average particle diameters are used under the same developing process condition, The coating amount tends to increase when a large particle diameter toner is used.
Further, since the toner has a uniform particle size distribution, the volume average particle size of the toner applied on the developing roller tends to be smaller than the volume average particle size of the toner in the developing unit, and the difference between the two Becomes larger as the volume average particle diameter of the toner in the developing unit becomes larger. . This relationship is shown in FIG. 1, for example. In FIG. 1, the horizontal axis represents the volume average particle diameter (μm) of the toner in the developing unit, and the vertical axis represents the volume average particle diameter (μm) of the toner on the developing roller. It is considered that this is because when the toner passes between the developing roller and the developer coating blade, the toner having a small particle diameter is likely to pass preferentially. Due to this phenomenon, the small particle size toner is developed first, and the toner particle size in the developing unit increases as the prints are piled up, and the toner particle size on the developing roller also increases. Therefore, by overlapping the prints as above,
The toner application amount on the developing roller increases, and the toner amount developed on the latent image holding member also increases.

Further, a certain amount of toner is developed and consumed,
When the toner in the developing unit becomes low, it is necessary to newly replenish a fixed amount of toner, and in this case, the volume average particle diameter of the toner in the developing unit becomes small again, so the amount of toner rapidly developed At the same time, the toner remaining in the developing unit and the toner replenished additionally are mixed, and toner with a low charge amount is generated, which causes background fog. Therefore, the volume average particle diameter of the toner (matrix colored particles) is set to 10 μm or less, and the particle diameter of the toner on the developing roller is stabilized (to the print) to stabilize the toner amount to be developed. Is possible. vice versa,
If the volume average particle size is less than 5 μm, the toner layer on the developing roller tends to be rough, and uniform charging cannot be provided between the developing roller and the developer coating blade, resulting in background fog. The side effects of are likely to occur. Therefore, the volume average particle diameter of the toner (base color particles) is 5 to
The thickness is preferably 10 μm.

For the purpose of imparting fluidity to the toner and obtaining sufficient developability and transferability without impairing the chargeability of the toner, hydrophobic silica fine powder is added in the present invention. . In this case, the present fine silica powder is added and mixed in an amount of 0.3 to 1.0 parts by weight (preferably 0.4 to 0.8 parts by weight) with respect to 100 parts by weight of the base colored particles. If the amount of fine silica powder added is less than 0.3 parts by weight, the effect of addition is small and the amount of toner developed may be insufficient. Conversely, if the amount added exceeds 1.0 parts by weight. In the case where the fine silica powder does not sufficiently adhere to the surface of the base colored particles and exists in a free state, and adheres to the latent image carrier or the surface of the developing roller to impart an abnormal charge to the toner. There is. Further, due to mechanical hazards in the developing unit, there are cases where the change in the toner characteristics due to the silica particles being embedded in the toner surface becomes large as described above.

In order to further stabilize the above characteristics, the hydrophobicity of the added hydrophobic silica is preferably 50% or more. By using the silica fine particles having a hydrophobicity of 50% or more, the above-described effects are stabilized, and changes in the charge amount and coating amount of the toner on the developing roller due to the environment in which they are used are reduced.

The volume average particle diameter of the mother colored particles can be measured by various methods, but in the present invention, the small hole passage method (Coulter counter method) was used. Coulter counter TA11 type (manufactured by Coulter, Inc.) is used as a measuring device, and 1% saline and an aperture of 100 μ are used as an electrolytic solution
It was measured as m.

Further, the "hydrophobicity" of the silica fine powder
Can be measured by the following method. 200 ml
50 ml of water is put into the beaker, and 0.2 g of fine silica powder is added. Then, while gently stirring with a magnetic stirrer, methanol was added from a buret whose tip was immersed in water at the time of dropping, and the floating silica fine powder began to sink, and read the number of ml of dropped methanol when completely sinking, Hydrophobicity = {ml of dropped methanol /
(50 + ml of dropped methanol)} × 100 (%). In this case, methanol acts as a surfactant, and the fine silica powder floating with the dropping of methanol disperses in water through methanol. Therefore, the larger the hydrophobicity value, the higher the hydrophobicity of the fine silica powder. Is high.

The degree of hydrophobicity of the fine silica powder can be controlled by subjecting the surface of the fine silica powder to a surface treatment (hydrophobic treatment) with a silane compound or the like. That is, the silane compound is reacted with the hydroxyl group bonded to the silica fine powder, and the hydroxyl group is replaced with a siloxyl group. Therefore, the degree of hydrophobization is lost by the above reaction among the hydroxyl groups present before hydrophobization. It is the ratio of the hydroxyl groups. The hydrophobic treatment is carried out by reacting fine silica powder with a dialkyldihalogenated silane, a trialkylhalogenated silane, a hexaalkyldisilazane, an alkyltrihalogenated silane or the like at a high temperature.

Further, in the toner of the present invention, when the absolute value of the charge amount of the mother colored particles is Q ₁ μC / g and the absolute value of the charge amount of the toner particles is Q ₂ μC / g, 0.8 < Q ₁ / Q ₂
The relationship <1.2 holds. In the developing process according to the present invention, when Q ₁ is higher than Q ₂ , fine silica powder adhering to the toner surface is embedded in the toner surface as the prints are piled up, and the toner on the developing roller is charged. The amount tends to increase, and the opposite is true when Q ₁ is smaller than Q ₂ . This is shown, for example, in FIG. In FIG. 2, the horizontal axis is Q ₁
/ Q ₂ ratio, and the vertical axis represents the charge amount ratio of the toner on the developing roller (after printing / at the start). It should be noted that “after printing” means a time point after the toner is developed and about 1,000 sheets are printed and before the toner is additionally replenished. Therefore, it is preferable that Q ₁ and Q ₂ are as close to each other as possible.

In addition, when the value of Q ₁ / Q ₂ is more than 1.2 or less than 0.8, when toner is developed and consumed and toner is newly replenished. However, it became clear that background fogging occurred. This is shown in Table 1. Further, the toner causing the background fog is the toner remaining in the developing unit when Q ₁ / Q ₂ is less than 0.8, and the additional toner is replenished when it is more than 1.2. It was revealed that the toner was a toner.

[Table 1]

The method for measuring Q ₁ and Q ₂ was as follows: Iron powder carrier (200 mesh pass, 300 mesh on) 19 was added to a ball mill at a rate of 60 g of toner 1 and
Rotate at 170 rpm for 30 minutes to mix. Next, 4 g of the mixture is sampled in a metallic measuring container having a 500-mesh screen on both bottoms of a cylindrical type, and the metallic lid is covered. The total weight at this time is measured and designated as W ₁ (g). Set it on the Plow machine and use 30 at 2.5 atm air
The second blow is performed, and the measured value of the electrometer at this time is read to be q (μC). W after blow
_{As 2} (g), the charge amount is measured by the following formula. Charge amount (μC / g) = q / (W ₁ −W ₂ ) Further, Q ₁ and Q ₂ are absolute values of the charge amount.

As a method of controlling Q ₁ from the toner constitution, it is necessary to properly select each of the binder resin, the charge control agent and the colorant contained in the mother colored particles, and in particular, the toner is charged. The selection of an effective charge control agent is an important factor. As the charge control agent, it is necessary to select a white to transparent color agent so as not to impair the color developability, transparency, color reproducibility and the like required for the color toner. As long as these conditions are satisfied so that Q ₁ becomes a constant value, it is possible to employ any one, but in order to stably obtain a particularly high charge amount, the metal of the salicylic acid derivative should be used. It is effective to add salt.

Examples of the salicylic acid derivative used here include compounds represented by the following general formula (I).

Embedded image (In the formula, R ¹ , R ² and R ³ are a hydrogen atom or a carbon number of 1 to 1.
0 is an alkyl group or an allyl group, and a hydrogen atom or an alkyl group having 1 to 6 carbon atoms or an allyl group is particularly desirable. Here, R ¹ , R ² and R ³ may be the same or different at the same time. Further, Me represents any metal selected from zinc, nickel, cobalt, copper, and chromium. )

The salicylic acid derivative is CLARK,
J. L. Kao, H (1948) J. Amer. Che
m. Soc. 70, 2151 and can be easily synthesized. For example, 2 mol of salicylic acid sodium salt (including a sodium salt of salicylic acid derivative) and 1 mol of zinc chloride are added to a solvent, mixed, heated and stirred to obtain a zinc salt. This metal salt is a white-colored crystal and does not show coloring even when dispersed in a toner binder. Metal salts other than zinc salts can also be produced according to the above method. Table 2 shows specific examples of particularly preferable compounds among the above salicylic acid derivatives.

[0029]

[Table 2]

The salicylic acid derivative represented by the general formula (I) imparts a negative charging property to the toner and exhibits the effect of controlling the change in the charge property of the toner with respect to the change in the environment. The compounding amount of the present compound is 0.1 to 10 parts by weight, preferably 1 to 7 parts by weight, based on 100 parts by weight of the binder resin. This compound has good dispersibility in the binder resin, and in particular, the above-mentioned effects can be obtained.

Regarding Q ₂ , the constitution of the hydrophobic silica mixed and coated on the surface of the mother colored particles described above is an important factor, but considering the relationship with Q ₁ ,
Select the appropriate conditions. Further, Q ₂ and the charge amount of the toner on the developing roller are in a proportional relationship as shown in FIG. Therefore, the charge amount of the toner on the developing roller should be Q ₂
Can be estimated from

Further, the charge amount of the toner on the developing roller is measured as follows. The toner attached to the developing roller is sucked through a Faraday cage having a filter layer on the outlet side, and the charge amount (Q / M) is calculated from the weight and charge amount of the toner trapped in the Faraday cage. The charge amount of the toner is -5 to -30 μC / g in consideration of sufficient developability and background fogging.
It is particularly preferably in the range of -10 to -20 μC / g. Therefore, Q ₁ and Q ₂ related to the main charge amount are 7.5 to 7
It is preferably 5 μC / g, particularly 25 to 50 μC / g.

Further, the toner of the present invention has a relationship of G ₂ % <G ₁ % <3 × G ₂ %, where G ₁ % is the aggregation degree of the mother colored particles and G ₂ % is the aggregation degree of the toner particles. Is established. The degree of coagulation of G ₁ and G ₂ in the present invention is measured by using a powder tester (manufactured by Hosokawa Micron Co., Ltd.), and sieves having openings of 75 μm, 45 μm and 22 μm are arranged in this order from the top, and 2 g of toner is placed on the sieve having openings of 75 μm. And vibrating for 30 seconds with an amplitude of 1 mm, and after vibrating, the toner weight on each sieve was measured, and 0.5, 0.3 and 0.
It is calculated as a percentage by multiplying and adding the weight of 1.

As described above, the toner in the developing unit is greatly affected by the flowability improver adhering to and adhering to the toner surface being embedded in the toner surface due to mechanical hazards in various units. Property deteriorates (cohesion increases), the amount of toner applied on the developing roller changes, and when a certain amount of new toner is replenished after printing is repeated, toner with different fluidity is mixed, which is sufficient. There is a case where the toner is not mixed and uneven toner is present even at the time of development, and uneven development occurs. In addition, when toners with different fluidity are present, the probability that both toners pass through the developing roller and the developer coating blade is different, the charge amount of the toner on the developing roller becomes unstable, and in some cases the cause of background fog may occur. Becomes
Therefore, it is preferable that the level of aggregation of the mother colored particles and the toner does not have a large level difference so that G ₁ % <3 × G ₂ %. G ₂ % is the developing property of the toner,
It is a characteristic that affects the transferability, and it is preferable to reduce these characteristics, but for the above reason, G
_{The range of 2} % <G ₁ % <3 × G ₂ % is preferable.

The amount of toner on the developing roller or the amount of toner developed on the latent image carrier is calculated from the weight change per unit area by peeling the toner layer with a tape (printable tape).

The colorant contained in the base colored particles used in the present invention is selected in consideration of the necessary color tone, color resistance, dispersibility in the binder resin selected, and the like. For example, carbon black, lamp black, ultramarine blue, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rotamin 6G,
It is selected from conventionally known dyes and pigments, such as dyes and pigments such as blue, chalco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal and triallylmethane dyes, and they are used alone or in combination. The amount of these colorants used is usually 1 to 30 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the binder resin.

As the binder resin contained in the base colored particles used in the present invention, known binder resins are used in consideration of necessary fixability, transparency, heat resistance, chargeability and the like. It is particularly preferable to use a polyester resin, an epoxy resin, a polyol resin, a styrene-acrylic resin, or the like for satisfying the properties.

In the present invention, a fine powder of hydrophobic silica (preferably having a hydrophobicity of 50% or more) is used as the external additive. If necessary, a fatty acid metal salt (zinc stearate, Aluminum stearate, etc.),
Metal oxides (titanium oxide, aluminum oxide, tin oxide,
Antimony oxide, etc.), fluoropolymer, etc. may be used together.

[0039]

The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention. All parts shown below are based on weight.

Example 1 Each of the compounds shown in Table 3 below was thoroughly mixed with a blender, and then melt-kneaded by a two-roll roller heated to 100 to 110 ° C. After naturally cooling the kneaded product, it was roughly pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then a wind classification device was used to obtain base colored particles of each color having a volume average particle size of 8.1 μm. .

[0041]

[Table 3]

Further, 0.5 part of silica fine powder having a hydrophobicity of 45%, which has been surface-treated with a silane coupling agent, is mixed with 100 parts of the base colored particles of each color by a Henschel mixer. , Toner of each color was obtained. The characteristics of this toner (cyan toner) were as follows. Q ₁ : 16 μC / g Q ₂ : 19 μC / g G ₁ : 55% G ₂ : 20%

On the other hand, the developing device shown in FIG. 4 (the developing roller is mainly composed of a silicone resin as a surface layer, and has a toner supply roller made of a polyurethane material contacting the main developing roller, and a blade made of urethane material contacting the main developing roller. , And the toner was set as shown in FIG. In FIG. 4, 1 is a latent image holding member (belt photosensitive member), 2 is a developing roller, 2-1 is a core metal, 2-2 is a resin coating layer, 3 is a toner supply member, 4 is a developer coating blade, 5 Is an agitator and 6 is a developing area. On the other hand, the developing device is installed in a modified Ricoh laser printer equipped with a belt-shaped organic photoconductor as a latent image carrier, and the linear velocity ratio of the developing roller / latent image carrier is 1.2. Then, the evaluation was carried out. Toner composition and evaluation results are shown in Tables 4 and 5, respectively. In this example, the latent image carrier and the developing roller were contacted for evaluation, but in the following examples, those which were contacted and not contacted (Gap: 150 μm).
The classification of m) is shown in Table 4.

After the image of each toner was transferred onto a copy sheet and fixed on a heat roller, a clear image of each color was obtained.
Similarly, clear images were obtained for red, blue, and green fixed images formed by two-color overlapping development and fixed images formed by three-color overlapping development. Further, the print was repeated, the toner in the developing device was consumed, and the cycle of supplying the toner when the toner was insufficient was repeated to print up to 30,000 sheets, but a clear image was maintained.

Example 2 Binder resin (polyol resin) 100 parts Charge control agent (tetraphenylboron salt) 4 parts Colorant (copper phthalocyanine blue pigment) 2 parts were treated in the same manner as in Example 1 to give a volume average particle size. 6.8 μm
To obtain cyan color mother colored particles. Furthermore, 0.4 part of silica fine powder having a hydrophobicity of 45%, which has been surface-treated with a silane coupling agent, is added to the cyan base color particles 100 described above.
Part of the toner was mixed with a Henschel mixer to obtain a toner. This toner was evaluated in the same manner as in Example 1. The toner configurations and evaluation results are summarized in Tables 4 and 5.

Example 3 Binder resin (polyester resin) 100 parts Charge control agent (salicylic acid derivative zinc salt *) 4 parts Colorant (copper phthalocyanine blue pigment) 2 parts were treated in the same manner as in Example 1 to give volume average particles. Diameter 8.8 μm
To obtain cyan color mother colored particles. Further, 0.6 part of silica fine powder having a hydrophobicity of 45%, which was surface-treated with a silane coupling agent, was added to the above cyan base color particles 100.
Part of the toner was mixed with a Henschel mixer to obtain a toner. This toner was evaluated in the same manner as in Example 1. The toner configurations and evaluation results are summarized in Tables 4 and 5. *) Specific compound No. Zinc [bis (3,5-di-tert-butyl-2-hydroxybenzoic acid]] shown as 1. The same applies to Examples 4 and 5 and Comparative Examples 1 and 4 to 6.

Example 4 Binder resin (polyol resin) 100 parts Charge control agent (salicylic acid derivative zinc salt) 4 parts Colorant (copper phthalocyanine blue pigment) 2 parts were treated in the same manner as in Example 1 to give a volume average particle size. 6.0 μm
To obtain cyan color mother colored particles. Further, 0.7 part of silica fine powder having a hydrophobicity of 45%, which was surface-treated with a silane coupling agent, was added to the above cyan base color particles 100.
Part of the toner was mixed with a Henschel mixer to obtain a toner. This toner was evaluated in the same manner as in Example 1. The toner configurations and evaluation results are summarized in Tables 4 and 5.

Example 5 Binder resin (polyester resin) 100 parts Charge control agent (salicylic acid derivative zinc salt) 4 parts Colorant (copper phthalocyanine blue pigment) 2 parts were treated in the same manner as in Example 1 to give a volume average particle size. 7.8 μm
To obtain cyan color mother colored particles. Furthermore, 0.75 parts of silica fine powder having a hydrophobicity of 70%, which was surface-treated with a silane coupling agent, was added to the cyan base color particles 10 described above.
0 part was mixed with a Henschel mixer to obtain a toner. This toner was evaluated in the same manner as in Example 1. Tables 4 and 5 show toner configurations and evaluation results.
It is summarized and described in.

Example 6 Binder resin (polyol resin) 100 parts Charge control agent (fluorine-containing quaternary ammonium salt compound) 4 parts Colorant (copper phthalocyanine blue pigment) 2 parts were treated in the same manner as in Example 1 to give a volume. Average particle size 6.6 μm
To obtain cyan color mother colored particles. Further, 0.8 part of silica fine powder having a hydrophobicity of 80%, which has been surface-treated with a silane coupling agent, is added to the cyan base color particles 100 described above.
Part of the toner was mixed with a Henschel mixer to obtain a toner. This toner was evaluated in the same manner as in Example 1. The toner configurations and evaluation results are summarized in Tables 4 and 5.

Comparative Example 1 Binder resin (polyester resin) 100 parts Charge control agent (salicylic acid derivative zinc salt) 4 parts Colorant (copper phthalocyanine blue pigment) 2 parts were treated in the same manner as in Example 1 to give a volume average particle size. 9.5 μm
To obtain cyan color mother colored particles. Further, 0.5 part of titanium oxide fine powder having a hydrophobicity of 45%, which was surface-treated with a titanium-based coupling agent, was added to the cyan base color particles 1 described above.
A toner was obtained by mixing 100 parts with a Henschel mixer. This toner was evaluated in the same manner as in Example 1. The toner configurations and evaluation results are summarized in Tables 4 and 5.

Comparative Example 2 Binder resin (polyol resin) 100 parts Charge control agent (fluorine-containing quaternary ammonium salt compound) 3 parts Colorant (copper phthalocyanine blue pigment) 2.5 parts The same as in Example 1 , Volume average particle size 10.2μ
m cyan colored mother particles were obtained. Further, 0.5 part of silica fine powder having a hydrophobicity of 45%, which has been surface-treated with a silane coupling agent, is used as the above cyan base color particles 10
0 part was mixed with a Henschel mixer to obtain a toner. This toner was evaluated in the same manner as in Example 1. Tables 4 and 5 show toner configurations and evaluation results.
It is summarized and described in.

Comparative Example 3 Binder resin (polyester resin) 100 parts Charge control agent (fluorine-containing quaternary ammonium salt compound) 4 parts Colorant (copper phthalocyanine blue pigment) 1.7 parts The same as in Example 1 , Volume average particle size 12.5μ
m cyan colored mother particles were obtained. Further, 0.7 part of silica fine powder having a hydrophobicity of 45%, which has been surface-treated with a silane coupling agent, was used as the cyan base color particles 10 described above.
0 part was mixed with a Henschel mixer to obtain a toner. This toner was evaluated in the same manner as in Example 1. Tables 4 and 5 show toner configurations and evaluation results.
It is summarized and described in.

Comparative Example 4 Binder resin (polyol resin) 100 parts Charge control agent (salicylic acid derivative zinc salt) 4 parts Colorant (copper phthalocyanine blue pigment) 2 parts were treated in the same manner as in Example 1 to give a volume average particle size. 6.0 μm
To obtain cyan color mother colored particles. Further, 0.2 part of fine silica powder having a hydrophobicity of 70%, which has been surface-treated with a silane coupling agent, is added to the cyan base color particles 100 described above.
Part of the toner was mixed with a Henschel mixer to obtain a toner. This toner was evaluated in the same manner as in Example 1. The toner configurations and evaluation results are summarized in Tables 4 and 5.

Comparative Example 5 Binder resin (polyester resin) 100 parts Charge control agent (salicylic acid derivative zinc salt) 1 part Colorant (copper phthalocyanine blue pigment) 2 parts were treated in the same manner as in Example 1 to give a volume average particle size. 9.5 μm
To obtain cyan color mother colored particles. Further, 1.3 parts of silica fine powder having a hydrophobicity of 70%, which was surface-treated with a silane coupling agent, was used as the cyan base color particles 100.
Part of the toner was mixed with a Henschel mixer to obtain a toner. This toner was evaluated in the same manner as in Example 1. The toner configurations and evaluation results are summarized in Tables 4 and 5.

Comparative Example 6 Binder resin (polyester resin) 100 parts Charge control agent (salicylic acid derivative zinc salt) 1 part Colorant (copper phthalocyanine blue pigment) 2 parts were treated in the same manner as in Example 1 to give a volume average particle size. 4.5 μm
To obtain cyan color mother colored particles. Further, 0.6 part of silica fine powder having a hydrophobicity of 70%, which was surface-treated with a silane coupling agent, was added to the above cyan base color particles 100.
Part of the toner was mixed with a Henschel mixer to obtain a toner. This toner was evaluated in the same manner as in Example 1. The toner configurations and evaluation results are summarized in Tables 4 and 5.

[0056]

[Table 4- (1)]

[0057]

[Table 4- (2)]

[0058]

[Table 5]

[0059]

The color toner for non-magnetic one-component development according to claim 1 has at least a hydrophobic property on the surface of the base colored particles having a volume average particle diameter of 5 to 10 μm and comprising at least a colorant, a binder resin and a charge control agent. A fine powder of silica is mixed and coated at a ratio of 0.3 to 1.0 parts by weight with respect to 100 parts by weight of the base colored particles, and the absolute value of the charge amount of the base colored particles is Q ₁ μC / g. The absolute value of the charge amount is Q ₂ μ
When C / g, the relationship of 0.8 <Q ₁ / Q ₂ <1.2 is established, and when the aggregation degree of the mother colored particles is G ₁ % and the aggregation degree of the toner particles is G ₂ %, , G ₂ % <G ₁ % <3
Since the relationship of × G ₂ % is established, the charge amount of the color toner on the developing roller is stabilized over time, and a sufficient amount of toner developed on the latent image holding member is stabilized. By ensuring the above, a stable high-quality color image can be obtained, and the background fog on the image can be prevented.

In the color toner for non-magnetic single-component development according to claim 2, since the salicylic acid derivative is used as the charge control agent, a high charge amount is stably imparted to the toner, so that a more stable high quality color image is obtained. Is obtained.

In the non-magnetic single-component developing color toner of claim 3, since the hydrophobic silica fine powder having a hydrophobicity of 50% or more is used, the change in toner characteristics is further reduced, and the toner is more stable. High quality color can be obtained.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the particle size of toner in a developing unit and the particle size of toner on a developing roller.

FIG. 2 is a graph showing the relationship between the Q ₁ / Q ₂ ratio and the toner charge amount ratio on the developing roller (after printing / at the start).

FIG. 3 is a graph showing a relationship between Q ₂ and a charge amount of toner on a developing roller.

FIG. 4 is a schematic cross-sectional view centering on a developing roller portion showing an example of a developing device useful for using the toner of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Latent image carrier (belt photoreceptor) 2 Development roller 2-1 Core metal 2-2 Resin coat layer 3 Toner supply member 4 Developer coating blade 5 Agitator 6 Development area

Claims (3)

[Claims] 1. A supply member for supplying toner onto a developing roller, and a developer coating blade provided on the downstream side of the supplying member are pressed against the developing roller, and the developing roller has a negative color. A color toner used in a method of multi-layer coating of toner and reversal development of a negative color toner in contact or non-contact with a latent image holding member composed of an organic photosensitive layer facing the developing roller, which is at least a colorant, 0.3 to 1.0 parts by weight of at least hydrophobic silica fine powder per 100 parts by weight of the base colored particles on the surface of the base colored particles having a volume average particle diameter of 5 to 10 μm, which is composed of a binder resin and a charge control agent. When the absolute value of the charge amount of the base colored particles is Q ₁ μC / g and the absolute value of the charge amount of the toner particles is Q ₂ μC / g, 0.8 <Q ₁ / Q ₂ The relationship <1.2 holds, and further, when the aggregation degree of the mother colored particles is G ₁ % and the aggregation degree of the toner particles is G ₂ %, G ₂ % <G ₁ % <3 × G ₂ % A non-magnetic one-component developing color toner characterized in that the relationship holds. 2. The non-magnetic one-component developing color toner according to claim 1, wherein the charge control agent is a metal salt of a salicylic acid derivative. 3. The hydrophobic silica fine powder has a hydrophobization degree of 5.
The color toner for non-magnetic one-component development according to claim 1, which is 0% or more.