JP3494612B2 - Toner for toner recycling system, method for manufacturing the same, and toner recycling developing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used in an image forming apparatus such as a copying machine and a printer, which uses electrophotography, and a surface of a photoconductor after a transfer process to a transfer material such as paper. The present invention relates to a toner recycling type developing method in which the remaining toner is reused as a developer component.

[0002]

2. Description of the Related Art Electrophotography is a technique in which a latent image is electrically formed on a photoconductor, and then the latent image is developed with toner in a developer, and toner is transferred to a transfer material such as paper when necessary. In this technique, after the image is transferred, the toner image is fixed on the transfer material by means such as heating and pressing to obtain a copy. Then, in the image forming apparatus using the electrophotographic technique, after the toner image developed on the surface of the photoconductor is transferred to the transfer material, the toner (a part of the toner image) remaining on the surface of the photoconductor is Generally, a system is used in which a cleaning blade, a fur brush, or the like is used to scrape the untransferred toner to a cleaning unit or a dedicated box.

Recently, for the purpose of resource saving and cost reduction, a toner recycling system has been provided in which the toner collected in the cleaning section is returned to the developer container for reuse. In the toner recycling system, satisfactory image characteristics are obtained in the initial stage. However, with the passage of life, an increase in background fog, a black spot (BS) phenomenon caused by the toner component contaminating the OPC (photoreceptor) surface, and an aggregate mainly composed of the toner component are generated in the developer. It has been found that the image error caused by is likely to occur.

As a result of researching and investigating such an increase in the background fog, the BS phenomenon and the phenomenon of the image error, the following causes have been found out as to the increase in the background fog. When the toner image is transferred from the OPC to the transfer material, only the toner is easily transferred. Therefore, the silica adhered to the toner surface in order to improve the charging stability, developability, fluidity, durability, etc. is left on the OPC without being transferred to the transfer material. The toner having the increased amount of silica in this manner is collected by the cleaning unit. In the recovered toner, silica is released from the toner and reaggregated. When the re-aggregated silica returns to the developer container, it adheres to the carrier surface in the developer and reduces the chargeability of the developer, resulting in an increase in background fog.

On the other hand, with respect to the BS phenomenon and the image error, the following causes have been found. Silica reaggregated in the collected toner is used as a nucleus, and toner particles and paper powder mixed in at the time of collecting the toner are attached to the core to form an aggregate. When such an aggregate is used as a developer, a BS phenomenon and an image error occur.

In order to prevent an increase in background fog, a BS phenomenon and an image error, it is effective to reduce the amount of free silica generated. The amount of free silica generated is determined by adding silica to the toner base and performing the adhesion treatment under the conditions of the adhesion treatment,
That is, it can be reduced by adjusting the stirring strength, stirring time and the like and firmly adhering silica to the surface of the toner base. However, in this case, the fluidity of the toner itself decreases,
The fluidity of the recovered toner is further reduced. Therefore, there arises a problem that the collected toner is clogged in the collected toner conveying path that leads from the cleaning section to the developing section.
Further, there is a problem that collected toner particles are likely to be strongly aggregated into toner lumps and an image error due to these toner lumps occurs.

[0007]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a toner for a toner recycling system, which is capable of preventing deterioration of image characteristics, contamination of a photoconductor and image error throughout its life in a toner recycling type developing method, and a method for producing the same. Another object of the present invention is to provide a toner recycling type developing method using this toner.

[0008]

In the toner for a toner recycling system of the present invention, silica having a particle diameter of 25 μm or more and 1.0% or less on a weight basis is used on the surface of a toner base.
A toner for a toner recycling system having an apparent density C of 0.29 to 0.32 g / ml, which is attached in an amount of 0.4 to 1.0% by weight based on the weight of the toner base, and the toner base is silica. The first stage adhesion treatment is performed with an amount of silica of 50% by weight or more and less than 100% by weight of the total amount of addition, and the second stage adhesion treatment is performed with the remaining silica, and the silica is not subjected to the adhesion treatment. Apparent density A (g / ml) of the toner base and apparent density B (g / m) of the toner base adhered by the first stage silica
and l) satisfy the relationship of 0.9 ≦ B / A ≦ 1.0. The amount of silica adhesion treatment in the second step is 0.05 to 0.2 with respect to the weight of the toner base.
It is desirable that the content is wt%.

Further, in the method for producing a toner for a toner recycling system of the present invention, silica having a particle size of 25 μm or more and 1.0% or less on a weight basis is used on the surface of the toner base.
A method for producing a toner for a toner recycling system, comprising adding 0.4 to 1.0% by weight to the weight of the toner base, and adhering the toner base with silica. 100% by weight or more
And the apparent density B (g / ml) of the toner matrix adhered with silica is 0.9 ≦ B / A ≦ A step of stirring a mixture of the toner base and silica so as to satisfy the relationship of 1.0, and applying adhesion treatment to the toner base with silica; and adding the remaining silica to the toner base adhered with silica The mixture of the toner base and the silica adhered by is stirred, and the toner base adhered by silica is further adhered by silica to obtain a toner having an apparent density C of 0.29 to 0.32 g / ml. And a process. The amount of the remaining silica is 0.05 to 0.2% by weight based on the weight of the toner base.
Is desirable.

In the toner recycling type developing method of the present invention, the electrostatic latent image formed on the surface of the photoconductor is developed with a developer containing toner, and the toner image on the surface of the photoconductor is transferred to a transfer material. After that, in the toner recycling type developing method in which the toner remaining on the surface of the photoconductor is collected and the collected toner is reused as a developer component, as the toner,
Silica having a particle diameter of 25 μm or more and 1.0% or less on a weight basis is attached to the surface of the toner base in an amount of 0.4 to 1.0% by weight based on the weight of the toner base, and an apparent density C of 0. A toner for a toner recycling system having an amount of 29 to 0.32 g / ml, wherein the toner base is subjected to a first stage adhesion treatment with an amount of silica of 50% by weight or more and less than 100% by weight based on the total amount of silica added, Further, the second stage of the adhesion treatment is performed with the remaining silica, and the apparent density A (g
/ Ml) and the apparent density B (g / ml) of the toner base adhered by the first stage silica are 0.9 ≦ B
It is characterized in that a material satisfying the relationship of /A≦1.0 is used.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
In the toner for the toner recycling system of the present invention, silica is attached to the surface of the toner base, and the apparent density C is 0.2.
A toner for a toner recycling system having a content of 9 to 0.32 g / ml, wherein the toner base is subjected to a first-stage adhesion treatment with an amount of silica of 50% by weight or more and less than 100% by weight of a total amount of silica added, 2 by the remaining silica
Apparent density A (g / m) of the toner base which has been subjected to the adhesion treatment of the second stage and has not been adhered by silica
1) and the apparent density B (g / ml) of the toner base material subjected to the adhesion treatment with the first stage silica are 0.9 ≦ B / A
The relationship of ≦ 1.0 is satisfied.

The toner base contains at least a binder resin and a colorant as main components, and optionally contains a low melting point wax, a charge control agent, a release agent and the like. Examples of the binder resin include styrenes such as styrene, α-methylstyrene, chlorostyrene, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, acrylates such as octyl acrylate, and methacrylic acid. Methacrylic acid esters such as ethyl, propyl methacrylate, butyl methacrylate, octyl methacrylate, stearyl methacrylate, glycidyl methacrylate, acrylonitrile, maleic acid, maleic acid ester, vinyl chloride, vinyl acetate, vinyl benzoate, vinyl methyl ketone. , Vinyl hexyl ketone, vinyl methyl ether, vinyl isobutyl ether and other vinyl monomers homopolymerized, or copolymerized styrene resins, acrylic resins and other vinyl resins, epoxy resins, polyesters Le resins, polyurethane resins and the like are used.

Examples of colorants include carbon black, aniline blue, chalco oil blue, chrome yellow, ultramarine blue, DuPont oil red,
Quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal and the like are used alone or in combination. The colorant needs to be contained in a sufficient proportion so that a visible image having a sufficient density can be formed.
It is contained in a proportion of about 1 to 20 parts by weight with respect to 100 parts by weight of the binder resin.

The low melting point wax is added for the purpose of lowering the melting start temperature of the toner to improve the low temperature fixing property. As the low melting point wax, for example, a synthetic wax, a petroleum wax, or the like is used. Examples of synthetic waxes include polypropylene wax and Fischer-Tropsch wax.
Examples of petroleum waxes include paraffin wax, microwax, petrotam and the like. As other waxes, natural waxes such as carnauba wax, rice wax, candelilla wax, and oil-based synthetic waxes are used.

The charge control agent is added to impart polarity, and is divided into positively charged toner and negatively charged toner. For positively charged toner, nigrosine dye, quaternary ammonium salt, viridinium salt, azine and the like are used. Further, for negatively charged toner, an azo metal-containing complex or a salicylic acid metal complex is used. The release agent is
It is added in order to secure the releasing property between the fixing heat roll and the toner. As the release agent, for example, low molecular weight polypropylene, low molecular weight polyethylene or the like is used.

The silica adheres to the surface of the toner base to prevent contamination of the surface of the photoconductor, background fog and image error. This silica may be hydrophobized with an organic silicon compound such as a silicone varnish, a silicone oil, or a silane coupling agent for the purpose of hydrophobizing and controlling the charging property.

As the silica, it is necessary to use silica having a particle diameter of 25 μm or more and 1.0% or less of silica particles on a weight basis. If the content of silica particles having a particle size of 25 μm or more exceeds 1.0%, the surface of the photoconductor is contaminated, resulting in an image error. It should be noted that the silica fine particles do not exist individually, but a large number of silica fine particles are aggregated, that is, in the state of secondary particles. Therefore, the particle diameter of the silica particles in the present invention means the particle diameter of the secondary particles formed by aggregating the silica fine particles. The particle size of silica can be determined from the weight distribution of secondary particles measured by a Coulter counter.

The total amount of silica added is 0.4 to 1.0% by weight based on the weight of the toner base. If the total amount of silica added is less than 0.4% by weight, contamination of the surface of the photoconductor occurs,
As a result, an image error occurs. In addition, the image density decreases when a large number of sheets are copied. In addition, ground fog increases. If the total amount of silica added exceeds 1.0% by weight, the surface of the photoconductor is contaminated, resulting in image error. In addition, ground fogging increases.

The toner for the toner recycling system of the present invention is obtained by performing the adhesion treatment of the toner base with silica in two steps. That is,
In the first stage, the toner base is 50% of the total amount of silica added.
It is obtained by subjecting a toner base adhered with silica in an amount of not less than 100% by weight to 50% by weight, preferably from 50 to 80% by weight, and adhered with silica in the second stage to an adhesion treatment with the remaining silica. It is a thing.

The amount of silica added in the first step for the adhesion treatment of the toner base is 50% of the total amount of silica added.
It is necessary that the content is not less than 100% by weight and less than 100% by weight. If the amount of silica added in the first step is less than 50% by weight, the surface of the photoconductor is contaminated, resulting in an image error. In addition, ground fogging increases.

The amount of silica added in the second stage is preferably 0.05 to 0.2% by weight based on the weight of the toner base. If the amount of silica added in the second stage is less than 0.05% by weight, the fluidity of the toner may be insufficient, and the toner may not be able to obtain a sufficient charge amount. The amount of silica added in the second stage is 0.2
When the content exceeds the weight%, silica is likely to be liberated from the toner base and silica aggregates are likely to occur. As a result, the surface of the photoconductor is contaminated and an image error occurs. In addition, ground fogging increases.

In the toner for the toner recycling system of the present invention, the apparent density A (g / ml) of the toner base not adhered by the silica and the toner base adhered by the silica added in the first step are compared. Apparent density B (g / ml) is 0.9 ≦ B / A ≦
It is important to satisfy the relationship of 1.0. When B / A is less than 0.9, the surface of the photoconductor is contaminated, resulting in an image error. When B / A exceeds 1.0, the surface of the photoconductor is contaminated, resulting in an image error. In addition, ground fogging increases. The apparent density in the present invention is an apparent density measured by a static method described in 20.1 of JIS K 5101 "Pigment test method".

The apparent density C of the toner for toner recycling system of the present invention is 0.29 to 0.32 g / m.
It is l. When the apparent density C is less than 0.29 g / ml,
Contamination of the surface of the photoreceptor occurs, resulting in image errors. In addition, the image density decreases when a large number of sheets are copied.
When the apparent density C exceeds 0.32 g / ml, the surface of the photoconductor is contaminated, resulting in an image error.
In addition, ground fogging increases. As described above, the toner for the toner recycling system of the present invention performs the adhesion treatment on the surface of the toner base with silica in two stages, but the adhesion treatment may be performed in three or more stages.

The toner for the toner recycling system of the present invention is manufactured as follows. First, the binder resin,
A colorant, and optionally a low-melting wax, a charge control agent, a release agent, etc. are put into a mixer such as a super mixer or a Henschel mixer, and after sufficiently mixed, a biaxial kneader, a heating roll, a kneader, etc. Heat kneading and kneading with the kneader. Then, the kneaded product is pulverized by a pulverizer such as a jet mill and classified by a classifier to obtain a toner base.

A method in which a predetermined amount of silica is added to the toner base and the mixture of the toner base and silica is stirred using a general stirrer such as a turbine stirrer, a Henschel mixer, a super mixer, or a surface reformer. The surface of the toner base is adhered with silica by a stirring method using a device called Nara Machinery Mfg. Co., Ltd. (Nara Hybridization System, Hosokawa Micron Co., Ltd., Ong Mill, etc.). According to the former method, silica adheres to the surface of the toner base in a sprinkled state, and by the latter method, silica adheres to the surface of the toner base in a fixed state. The term “adhesion” as used in the present invention means both the state of the glaze and the state of fixation. In the adhesion treatment, the apparent density A (g / ml) of the toner base not adhered by silica and the apparent density B (g / ml) of the toner base adhered by silica are 0.9 ≦ B.
This is performed until the relationship of /A≦1.0 is satisfied.

Next, the remaining silica is added to the toner adhered by silica, the mixture is stirred by a stirrer, and the toner base adhered by silica is further adhered by silica. In this way, the toner for the toner recycling system of the present invention is obtained.

In the method for producing a toner for a toner recycling system of the present invention, first, the apparent density A (g
/ Ml) and the apparent density B (g / ml) are 0.9 ≦
Since the surface of the toner base is adhered by silica so as to satisfy the relationship of B / A ≦ 1.0, the silica is sufficiently fixed to the surface of the toner base, and the release of silica from the toner is prevented. Since the toner adhered by silica is further adhered by a small amount of silica, the fluidity of the toner is improved, and a toner having good chargeability can be obtained. As a result, it is possible to obtain a toner capable of forming an image having a sufficient image density with less background fog and contamination of the photoconductor.

Next, the toner recycling type developing method of the present invention using the developer containing the toner for the toner recycling system of the present invention will be described in detail. FIG. 1 is a schematic view of a developing device used in the toner recycling type developing method of the present invention. This developing device includes a cylindrical photosensitive drum 1 which is an electrostatic latent image holder, a corona charger 2 which uniformly charges the surface of the photosensitive drum 1, and an electrostatic latent image on the surface of the photosensitive drum 1. A developing device 4 including a combination of an optical system 3 to be formed, a developer container 4a containing a developer 6 and a developing sleeve 4b installed with a certain gap from the photosensitive drum 1, and a developer. The toner image 6a developed on the electrostatic latent image portion is transferred to the recording sheet 7 (transfer material) by the corona transfer device 5, and the toner 6b remaining on the surface of the photosensitive drum 1 without being transferred to the recording sheet 7 is scraped. Cleaning blade 9a to be dropped and collected toner 6
The toner collecting means 9 is composed of a collecting and conveying path 9b for returning b to the developer accommodating container 4a, and a discharging means 10 for discharging the surface of the photosensitive drum 1 is constructed.

The toner recycling type developing method of the present invention using this developing device is carried out as follows. First,
The surface of the rotating photoconductor drum 1 is uniformly charged by the corona discharge of the corona charger 2. Then, an electrostatic latent image is formed on the surface of the photosensitive drum 1 by the exposure of the optical system 3. The developing sleeve 4b rotates while adsorbing the developer 6 contained in the developer container 4a, and the toner in the developer 6 has a polarity opposite to that of the electrostatic latent image formed on the surface of the photosensitive drum 1. It is absorbed by action. As a result, the electrostatic latent image is visualized as the toner image 6a.

Next, the recording sheet 7 is conveyed between the photoconductor drum 1 and the corona transfer device 5 and superposed on the toner image 6a, and a transfer charge is given from the back surface of the toner image 6a by the corona transfer device 5, thereby recording. Toner image 6a on sheet 7
Is transcribed. After that, the recording sheet 7 is fixed to the fixing roller pair 8
The toner image 6a is fixed on the recording sheet 7 at that time. On the other hand, the toner 6b remaining on the surface of the photosensitive drum 1 without being transferred to the recording sheet 7 is scraped off by the cleaning blade 9a, whereby the surface of the photosensitive drum 1 is cleaned. After that, the surface of the photoconductor drum 1 is discharged by the discharging unit 10. The toner 6b scraped off by the cleaning blade 9a is returned to the developer accommodating container 4a via the collecting / conveying path 9b and is used again.

In the toner recycling type developing method of the present invention, since the toner for the toner recycling system of the present invention is used as the toner, it is possible to prevent an increase in background fog, contamination of the surface of the photoreceptor and an image error. it can.

[0032]

The present invention will be described in more detail based on the following examples. [Physical Property Measuring Method and Actual Photograph Evaluation Method] (Apparent Density) The apparent density was measured according to JIS K 5101. (Image Density) The black solid image portion on the transfer material was measured with a reflection densitometer RD-914 manufactured by Macbeth. (Ground fog) Colors made by Nippon Denshoku Industries Co., Ltd.
It was measured with a meter ZE2000. (Charge amount) The triboelectric charge amount of the toner was measured with a blow-off powder charge amount machine TB-200 manufactured by Toshiba Chemical Corporation.

(Image error) Abnormal portions such as points or lines other than the copy original which were developed on the copied image were visually confirmed and the number thereof was counted. (OPC contamination) Grooves on the surface of the organic photoconductor (OPC) or the adhered (black) part of the toner component are visually confirmed,
I counted the number. (Silica Concentration) The silica concentration was measured with a fluorescent X-ray analyzer (JSX-3201, manufactured by JEOL Ltd.).

(Preparation of Silica) The silica used in this example was prepared as follows. Coulter Counter (Beckman Coulter Co., Coulter Counter T
In the weight distribution of the secondary particle state measured in A-II),
Positively charged silica A containing 10.8% of silica particles having a particle diameter of 25 μm or more was charged into a Henschel mixer and stirred for 3 minutes under the condition that the peripheral speed of the stirring blade was 40 m / s, and the particle diameter was 25 μm or more. A silica B having a silica particle ratio of 0.8% was prepared. Similarly, silica A was stirred for 1 minute under the condition that the peripheral speed of the stirring blade was 40 m / s, and the particle diameter was 25 μm.
The silica C in which the ratio of the above silica particles was 1.5% was produced.

Example 1 (Preparation of Toner Base) Binder Resin (Styrene-Acrylate Ester Copolymer Resin, Mitsui Toatsu Chemical Co., Ltd., CPR-1)
00) 92 parts by weight, low melting point wax (low molecular weight polypropylene wax, manufactured by Sanyo Chemical Industry Co., Ltd., Viscole 330)
P) 3 parts by weight, charge control agent (metal-containing dye, manufactured by Orient Chemical Industry Co., Ltd., BONTRON N-04) 2 parts by weight, and colorant (carbon black, manufactured by Mitsubishi Chemical Corporation, # 40).
5 parts by weight are mixed with a super mixer, hot melt kneaded with a twin-screw kneader, pulverized with a jet mill, and then classified with a dry classifier to have a number average particle diameter of 9.5 μm and an apparent density A.
To give 0.27 g / ml of toner base particles.

(Preparation of Toner for Toner Recycling System) Toner base particles and the weight of the toner base are 0.
Charge 5% by weight of silica B and Henschel mixer,
Stirring was carried out for 15 minutes under the condition that the peripheral speed of the stirring blade was 30 m / s. The apparent density B of the toner base treated with silica was 0.26 g / ml. Next, 0.2% by weight of silica B was added to the weight of the toner base, and 2
After stirring for a minute, a toner for a toner recycling system having an apparent density C of 0.31 g / ml was produced.

(Preparation of developer for evaluation) Average particle size of about 60 μm
A positive charging ferrite carrier (F921-2035 manufactured by Powder Tech Co., Ltd.) and a toner for a toner recycling system were mixed so that the toner concentration would be 5% by weight, and these were mixed in a V blender to be a developer for evaluation. Was produced.

(Evaluation of Actual Image) The evaluation developer was put into the developing device for the recycling system to perform copying, and the charge amount, image density, background fog and image error were measured at the start of copying and after copying 30,000 sheets. . Also, the number of contaminants on the OPC surface after copying 30,000 sheets was confirmed. Further, in order to confirm the condensed state of silica, recycled toner was collected from the cleaning unit at the end of printing of 30,000 sheets, and the silica concentration was confirmed by a fluorescent X-ray analyzer. The results are shown in Table 1. As the developing device for the recycling system, a pseudo-recycling system copying machine as shown in FIG. 1 was used in which the cleaned toner was returned to the developing section and the collected toner was processed so as to be repeatedly used.

[Example 2] The amount of silica B added during the first stage adhesion treatment was 0.3% by weight, and the treatment time was 10 minutes.
Apparent density C was obtained in the same manner as in Example 1 except that the amount of silica B added during the second stage adhesion treatment was 0.1% by weight.
To obtain 0.29 g / ml of toner for toner recycling system. The apparent density B of the toner treated with the first stage silica was 0.26 g / ml. The evaluation results are shown in Table 1. [Example 3] The apparent density C was 0.30 g in the same manner as in Example 1 except that the addition amount of silica B in the first-stage adhesion treatment was 0.2% by weight and the treatment time was 3 minutes. / Ml of toner for toner recycling system was obtained. The apparent density B of the toner treated with the first stage silica is 0.25 g
/ Ml. The evaluation results are shown in Table 1.

Example 4 The apparent density C was the same as in Example 1 except that the amount of silica B added during the first stage adhesion treatment was 0.8% by weight and the treatment time was 20 minutes. 0.3
2 g / ml of toner for toner recycling system was obtained. The apparent density B of the toner treated with the first stage silica was 0.27 g / ml. The evaluation results are shown in Table 1.

Comparative Example 1 A toner having an apparent density C of 0.30 g / ml was obtained in the same manner as in Example 1 except that silica A was used as the silica to be added. The apparent density B of the toner treated with the first stage silica is 0.26 g.
/ Ml. The evaluation results are shown in Table 1. Particle size 25μ
When silica having a ratio of m or more silica particles of 1.0% or more was used, OPC contamination and image error occurred. [Comparative Example 2] The apparent density C was 0.2 in the same manner as in Example 2 except that silica A was used as the silica to be added.
9 g / ml of toner was obtained. The apparent density B of the toner treated with the first stage silica was 0.25 g / ml. The evaluation results are shown in Table 1. When silica having a ratio of silica particles having a particle diameter of 25 μm or more is 1.0% or more, O
PC contamination and image error occurred.

Comparative Example 3 A toner having an apparent density C of 0.29 g / ml was obtained in the same manner as in Example 2 except that silica C was used as the silica to be added. The apparent density B of the toner treated with the first stage silica is 0.25 g
/ Ml. The evaluation results are shown in Table 1. Particle size 25μ
When silica having a ratio of m or more silica particles of 1.0% or more was used, OPC contamination and image error occurred. [Comparative Example 4] The total amount of silica added was 0.4% by weight, and 2
Apparent density was performed in the same manner as in Example 1 except that only one-step adhesion treatment (stirring for 2 minutes under the condition that the peripheral speed of the stirring blade was 40 m / s) was performed without performing the step-wise adhesion treatment. A toner having C of 0.31 g / ml was obtained. The evaluation results are shown in Table 1. When the two-step adhesion treatment with silica was not performed, OPC contamination, image errors occurred, and the background fog increased.

[Comparative Example 5] The apparent density C was 0.28 in the same manner as in Comparative Example 4 except that the stirring time was 15 minutes.
g / ml toner was obtained. The evaluation results are shown in Table 1. When a toner having an apparent density C of less than 0.29 g / ml was used without performing the two-step adhesion treatment with silica, OPC contamination and an image error occurred. In addition, the image density decreased when copying a large number of sheets. [Comparative Example 6] The apparent density C was 0.2 in the same manner as in Comparative Example 4 except that the total amount of silica B added was 0.3% by weight.
9 g / ml of toner was obtained. The evaluation results are shown in Table 1. When the two-step adhesion treatment with silica was not carried out and a toner containing less than 0.4% by weight of the total amount of silica was used, OPC contamination, image errors occurred, and the background fog increased. In addition, the image density decreased when copying a large number of sheets.

[Comparative Example 7] The total amount of silica B added was 1.0.
A toner having an apparent density C of 0.30 g / ml was obtained in the same manner as in Comparative Example 4 except that the weight percentage was 40% and the stirring time was 40 minutes. The evaluation results are shown in Table 1. When the two-step adhesion treatment with silica was not performed, OPC contamination, image errors occurred, and the background fog increased. [Comparative Example 8] Except that the peripheral speed of the stirring blade and the stirring time during the second stage of the adhesion treatment were 20 m / s and 30 seconds, respectively.
Similar to Example 2, the apparent density C is 0.33 g / m.
l toner was obtained. The apparent density B of the toner treated with the first stage silica was 0.26 g / ml. The evaluation results are shown in Table 1. When a toner having an apparent density C of more than 0.32 g / ml was used, OPC contamination, image error occurred, and the background fog increased.

[Comparative Example 9] A toner having an apparent density C of 0.30 g / ml was obtained in the same manner as in Example 3 except that the stirring time in the first-stage adhesion treatment was 1 minute.
Apparent density B of toner treated with first stage silica
Was 0.28 g / ml. The evaluation results are shown in Table 1. When a toner having a B / A of more than 1 was used, OPC contamination, image errors occurred, and the background fog increased. [Comparative Example 10] The amount of silica B added during the first stage adhesion treatment was 0.1% by weight, the amount of silica B added during the second stage adhesion treatment was 0.3% by weight, and the stirring time was 5%. The apparent density C was 0.29 in the same manner as in Example 3 except that the time was set to be 9 minutes.
A g / ml toner for a toner recycling system was obtained.
Apparent density B of toner treated with first stage silica
Was 0.26 g / ml. The evaluation results are shown in Table 1. When the amount of silica added during the first stage adhesion treatment was less than 50% by weight of the total amount of silica added, OPC contamination and image errors occurred, and the background fog increased.

[Comparative Example 11] The amount of silica B added during the first-stage adhesion treatment was 1.0% by weight, and the peripheral speed of the stirring blade was 40.
m / s, the stirring time was 40 minutes, and the apparent density C was 0.30 g in the same manner as in Example 3 except that the addition amount of silica B in the second stage adhesion treatment was 0.2% by weight. / Ml
To obtain a toner for a toner recycling system. The apparent density B of the toner treated with the first stage silica is 0.2
It was 7 g / ml. The evaluation results are shown in Table 1. When a toner in which the total amount of silica added exceeds 1.0% by weight,
OPC contamination, image errors occurred, and the background fog increased. [Comparative Example 12] The stirring time during the first stage adhesion treatment was 30
A toner for a toner recycle system having an apparent density C of 0.30 g / ml was obtained in the same manner as in Example 1 except that the time was changed. The apparent density B of the toner treated with the first stage silica was 0.24 g / ml. The evaluation results are shown in Table 1. When a toner having a B / A of less than 0.9 was used, OPC contamination and image error occurred.

[0047]

[Table 1]

[0048]

As described above, in the toner for the toner recycling system of the present invention, silica having a particle diameter of 25 μm or more and 1.0% or less on the weight basis of the toner base is the weight of the toner base. 0.4 to 1.0% by weight is attached, and the apparent density C is 0.29 to 0.32 g / m.
1 is a toner for a toner recycling system,
The toner base is 50% by weight or more of the total amount of silica added 1
The first stage adhesion treatment is performed with an amount of silica less than 00% by weight, and the second stage adhesion treatment is further performed with the remaining silica. The apparent density A (g / Ml) and the apparent density B of the toner base adhered by the first stage silica.
Since (g / ml) satisfies the relationship of 0.9 ≦ B / A ≦ 1.0, it is possible to suppress an increase in background fog, prevent deterioration of image characteristics, and prevent contamination of the photoreceptor and Image errors can be prevented. Further, when the amount of silica adhesion treatment in the second step is 0.05 to 0.2% by weight with respect to the weight of the toner base, a toner excellent in fluidity and chargeability can be obtained, and , Deterioration of image characteristics,
It is possible to prevent the contamination of the photoconductor and the image error.

Further, in the method for producing a toner for a toner recycling system of the present invention, silica having a particle size of 25 μm or more and 1.0% or less on a weight basis is used on the surface of the toner base.
A method for producing a toner for a toner recycling system, comprising adding 0.4 to 1.0% by weight to the weight of the toner base, and adhering the toner base with silica. 100% by weight or more
And the apparent density B (g / ml) of the toner matrix adhered with silica is 0.9 ≦ B / A ≦ A step of stirring a mixture of the toner base and silica so as to satisfy the relationship of 1.0, and applying adhesion treatment to the toner base with silica; and adding the remaining silica to the toner base adhered with silica The mixture of the toner base and the silica adhered by is stirred, and the toner base adhered by silica is further adhered by silica to obtain a toner having an apparent density C of 0.29 to 0.32 g / ml. According to such a manufacturing method, the increase in the background fog is suppressed, the deterioration of the image characteristics is prevented, and the contamination of the photoconductor and the image error are prevented. It is possible to obtain a toner to stop. When the amount of the remaining silica is 0.05 to 0.2% by weight based on the weight of the toner base material, the fluidity and chargeability are excellent, the image characteristics are deteriorated, and the photoreceptor is contaminated. It is possible to obtain toner that prevents image errors.

In the toner recycling type developing method of the present invention, the electrostatic latent image formed on the surface of the photoconductor is developed with a developer containing toner, and the toner image on the surface of the photoconductor is transferred to a transfer material. After that, in the toner recycling type developing method in which the toner remaining on the surface of the photoconductor is collected and the collected toner is reused as a developer component, as the toner,
Silica having a particle diameter of 25 μm or more and 1.0% or less on a weight basis is attached to the surface of the toner base in an amount of 0.4 to 1.0% by weight based on the weight of the toner base, and an apparent density C of 0. A toner for a toner recycling system having an amount of 29 to 0.32 g / ml, wherein the toner base is subjected to a first stage adhesion treatment with an amount of silica of 50% by weight or more and less than 100% by weight based on the total amount of silica added, Further, the second stage of the adhesion treatment is performed with the remaining silica, and the apparent density A (g
/ Ml) and the apparent density B (g / ml) of the toner base adhered by the first stage silica are 0.9 ≦ B
Since one that satisfies the relationship of /A≦1.0 is used,
It is possible to suppress an increase in background fog, prevent deterioration of image characteristics, and prevent contamination of the photoconductor and image error.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a developing device used in a toner recycling type developing method of the present invention.

[Explanation of symbols]

1 ... Photosensitive drum (photosensitive member), 6 ... Developer, 6a ... Toner image (toner), 6b ... Toner remaining on photosensitive member surface, 7 ... Recording sheet (transfer material)

Continuation of the front page (56) Reference JP-A-3-116054 (JP, A) JP-A-4-177258 (JP, A) JP-A-8-137123 (JP, A) JP-A-9-34160 (JP , A) JP 10-186712 (JP, A) JP 7-209903 (JP, A) JP 8-292597 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) G03G 9/08

Claims (5)

(57) [Claims] 1. Silica having a particle diameter of 25 μm or more and 1.0% or less on a weight basis is adhered to the surface of the toner base material in an amount of 0.4 to 1.0% by weight based on the weight of the toner base material. A toner for a toner recycling system having a density C of 0.29 to 0.32 g / ml, wherein the toner base is 50% by weight or more of the total amount of silica added 1
The first stage adhesion treatment is performed with an amount of silica less than 00% by weight, and the second stage adhesion treatment is further performed with the remaining silica. The apparent density A (g / Ml) and the apparent density B of the toner base adhered by the first stage silica.
(G / ml) satisfies the relation of 0.9 ≦ B / A ≦ 1.0. Toner for a toner recycling system. 2. The amount of silica deposited in the second stage is 0.05 to 0.2% by weight based on the weight of the toner base.
The toner for a toner recycling system according to claim 1, wherein 3. Silica having a particle diameter of 25 μm or more and 1.0% or less on a weight basis is added to the surface of the toner base in an amount of 0.4 to 1.0% by weight based on the weight of the toner base. A method for producing a toner for a toner recycling system, wherein a toner base is subjected to adhesion treatment with silica, wherein the toner base is added with 50% by weight or more and less than 100% by weight of the total amount of silica, and the appearance of the toner base not treated with silica is added. Density A (g / ml) and apparent density B (g / m) of the toner base that has been treated with silica.
l) and the relationship of 0.9 ≦ B / A ≦ 1.0 are satisfied, the step of stirring the mixture of the toner base and silica, and applying the adhesion treatment to the toner base with silica; The remaining silica is added to the toner base, the mixture of the toner base adhered with silica and silica is stirred, and the toner base adhered with silica is further adhered with silica to give an apparent density C of 0. 29. A method for producing a toner for a toner recycling system, which comprises a step of obtaining a toner of 29 to 0.32 g / ml. 4. The method for producing a toner for a toner recycling system according to claim 3, wherein the amount of the remaining silica is 0.05 to 0.2% by weight based on the weight of the toner base. 5. An electrostatic latent image formed on the surface of a photoconductor,
In a toner recycling type developing method of developing with a developer containing toner, transferring the toner image on the surface of the photoconductor to a transfer material, collecting the toner remaining on the surface of the photoconductor, and reusing the collected toner as a developer component As the toner, silica having a particle diameter of 25 μm or more and 1.0% or less on a weight basis is attached to the surface of the toner base material in an amount of 0.4 to 1.0% by weight based on the weight of the toner base material. A toner for a toner recycling system having a density C of 0.29 to 0.32 g / ml, wherein the toner base has a first amount of silica of 50% by weight or more and less than 100% by weight of the total amount of silica added. Treatment, and the second stage of the adhesion treatment with the remaining silica, and the apparent density A (g / ml) of the toner base not subjected to the adhesion treatment with silica. Mother toner which is deposited processed by the first stage silica apparent density B (g / m
The toner recycling type developing method is characterized in that a toner satisfying the relation of 1) and 0.9 ≦ B / A ≦ 1.0 is used.