JP2007086812A - Method for manufacturing developer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the occurrence of filming. <P>SOLUTION: The method comprises: a process of kneading a resin and a colorant; a process of subjecting the kneaded mixture composed of the kneaded resin and colorant to rough pulverization; a process of adding an external additive to the developer main body particle obtained by the rough pulverization; a process of subjecting the developer main body particle added with the external additive to fine grinding; and a process of classifying the particle subjected to fine grinding. The external additive is made to adhere powerfully to the surface of the developer main body particle by the energy given in the next fine grinding process and therefore, the extremely small suspended external additive as compared to the grain size of the toner which is a product is eventually removed. Neither of the developing blade filming nor the photoreceptor drum filming occur and the extremely satisfactory printed matter can by stably obtained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a developer.

  2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, the surface of a photosensitive drum is uniformly and uniformly charged by a charging roller, and then the surface of the photosensitive drum is exposed to electrostatic by an LED head. A latent image is formed. Then, in the developing device, toner as a developer is attached to the electrostatic latent image, development is performed, a toner image is formed, and the toner image is transferred onto a sheet as a medium by a transfer roller. Subsequently, the sheet on which the toner image is transferred is sent to a fixing device, and the toner image is fixed on the sheet in the fixing device. For this purpose, the fixing device includes a heating roller for heating and melting the toner of the toner image, and a pressure roller for pressing the toner image.

  By the way, in the fixing device, in order to obtain sufficient fixing performance, it is necessary to make the toner used as the developer easily meltable. In some cases, a release agent may be added to the toner, and the release agent often has a characteristic that it is more easily melted than the resin constituting the toner.

  Therefore, by utilizing this characteristic, the toner can be more easily melted and the fixing performance can be further improved. Further, by taking advantage of the original releasability of the release agent, it is possible to prevent the occurrence of a hot offset phenomenon in which the toner melted in the fixing device is fused to the heating roller (ensuring an offset margin).

  By the way, as the release agent, for example, a synthetic wax such as polyethylene or polypropylene, or a natural wax such as carnauba is added to a resin that is a main component of the toner alone or in combination. Also, softeners such as fatty acid esters are known to have an equivalent release effect and may be used as a release agent.

  In particular, in a color electrophotographic image forming apparatus such as a color printer or a color copying machine, unlike a monochrome image forming apparatus, when an OHP sheet is used as a medium, good OHP transparency is ensured. Is required. Therefore, it is necessary to make the toner more easily meltable.

  Further, in the toner, generally, toner particles containing crystal resin (hereinafter referred to as “developer main body particles”) and fluidizing agents (hereinafter referred to as “external additives”) are used to reduce viscosity and increase fluidity. ), And for example, silicon oxide (hereinafter referred to as “silica”), silica surface-treated product, titanium, titanium oxide, titanium oxide surface-treated product, clay, alumina Inorganic abrasives such as calcium carbonate, or organic abrasives such as methacrylate resin abrasives, melanin resin abrasives, and silicone abrasives are used.

  The diameter of the external additive, that is, the particle size is smaller than that of the developer main body particle, and is about 2 to 5000 [nm], and generally about 5 to 2000 [nm].

Further, in the toner manufacturing process, the external additive is attached to the surface of the developer main body particles using an external addition device such as a Henschel mixer, and the toner is completed (see, for example, Patent Document 1). .)
JP-A-7-92727

However, in the conventional image forming apparatus, 1 part by weight of R972 (manufactured by Nippon Aerosil Co., Ltd.) as the external additive has a viscosity of 1 × 10 ⁴ [poise] at 105 ° C. by a flotester. RX50 (manufactured by Nippon Aerosil Co., Ltd.) is used, and a durability printing test is performed. As a result, toner, external additives, and the like adhere to the surface of the developing blade, the photosensitive drum, and the like. For example, developing blade filming, photosensitive drum filming, etc. occur.

  In addition, the developing blade filming does not occur in a long range as in the printing of thousands to tens of thousands as normally observed, but also occurs in printing of several hundred sheets. Also, in color printing, unlike monochrome printing, photographic images, poster images, and the like having a high printing duty are often printed continuously, and development blade filming further occurs. Furthermore, when toner having a low viscosity at the time of melting is used, developing blade filming occurs even when a document having a low printing duty is printed.

  On the other hand, the possibility of photoconductor drum filming is slightly lower than the possibility of developing blade filming, but when a toner having a low viscosity property at the time of melting is used, a photo with a high printing duty is used. When an image, a poster image, or the like is printed continuously, photoconductor drum filming occurs.

  An object of the present invention is to solve the problems of the conventional image forming apparatus and to provide a developer manufacturing method capable of suppressing the occurrence of filming.

  Therefore, the developer production method of the present invention is obtained by kneading a resin and a colorant, performing a coarse pulverization on a kneaded material composed of the kneaded resin and the colorant, and coarse pulverization. A step of adding an external additive to the developer main body particles, a step of finely pulverizing the developer main body particles to which the external additive is added, and a step of classifying the finely pulverized particles. .

  According to the present invention, the developer production method is obtained by kneading the resin and the colorant, roughly pulverizing the kneaded material composed of the kneaded resin and the colorant, and coarse pulverization. A step of adding an external additive to the developer main body particles, a step of finely pulverizing the developer main body particles to which the external additive is added, and a step of classifying the finely pulverized particles. .

In this case, the external additive is strongly attached to the surface of the developer main body particles by the energy given in the fine pulverization step. Even if the floating external additive remains due to the addition of the external additive, the floating external additive that is extremely small compared to the particle size of the product toner is removed in the classification step after the fine pulverization step. End up. The floating external additive in this toner was 1 × 10 ⁻⁶ parts by weight, which was a fraction of that of a toner prepared by a usual method.

  When printing is performed using this toner, neither development blade filming nor photosensitive drum filming occurs even when 50,000 sheets are printed, and an extremely good printed matter can be stably obtained. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a conceptual diagram of an electrophotographic image forming apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view of a developer cartridge according to the embodiment of the present invention.

  In the figure, 11 is a photosensitive drum as an image carrier rotated in the direction of arrow a, 12 is rotated in the direction of arrow b in contact with the photosensitive drum 11, and a voltage is applied by a power source (not shown) to be photosensitive. It is a charging roller as a charging device for charging the body drum 11, and a non-contact charging device such as scorotron or corotron can be used instead of the charging roller.

  Reference numeral 13 denotes an LED head as an exposure device that forms an electrostatic latent image on the photosensitive drum 11 charged by the charging roller 12, and a laser or the like can be used instead of the LED head. 14 is set to be in contact with or not in contact with the photosensitive drum 11 and rotated in the direction of the arrow c to carry the toner 16 as a developer to the developing area and attach the toner 16 to the electrostatic latent image. A developing roller 15 as a developer carrying member that forms a toner image by visualizing an electrostatic latent image is set to contact or non-contact with the developing roller 14 and is rotated in the direction of arrow d to A toner supply roller 16 supplies 16 to the developing roller 14, and a developing blade 17 serves as a developer regulating member that thins the toner 16 supplied to the developing roller 14 by the toner supply roller 16. The developing roller 14, the toner supply roller 15 and the developing blade 17 constitute a developing device.

  Further, 18 is arranged in contact with the photosensitive drum 11 and rotated in the direction of arrow e, and a toner image on the photosensitive drum 11 visualized by applying a voltage by a power source (not shown) is changed to an arrow. It is a transfer roller as a transfer device for transferring to a sheet 22 as a medium such as a sheet conveyed in the h direction or an OHP sheet, and a non-contact corotron type transfer apparatus can be used instead of the transfer roller 18. . Reference numeral 19 denotes a cleaning device that removes the toner 16 remaining on the photosensitive drum 11 after the transfer process is completed and the toner image is transferred to the paper 22, and in this embodiment, a rubber blade is used. A blade cleaning type cleaning device in contact with the photosensitive drum 11 is used. In place of the rubber blade, a roller type cleaning device or a brush type cleaning device that removes the toner 16 remaining on the photosensitive drum 11 while rotating in contact with the photosensitive drum 11 may be used. it can.

  Reference numeral 10 denotes a fixing device for fixing the transferred toner image on the paper 22. The fixing device 10 is rotated in the direction of the arrow f, and the surface is heated by the supply of heat from a power source (not shown). A heating roller 20 that heats and melts the toner 16 of the toner image transferred onto 22 and a pressure roller 21 that rotates in the direction of arrow g and presses the melted toner 16 against the paper 22 are provided. In this embodiment, the roller type fixing device 10 is used. However, a belt type using a belt, a film type using a film, a flash type using light emission energy, and the like. Can also be used. In the roller type or belt type fixing device, oil is supplied to the heating roller 20, belt, etc. by an oil supply fixing system having an oil supply mechanism such as an oil supply roller, an oil supply sheet, and an oil tank. The hot offset phenomenon is prevented from occurring. Further, the oil does not need to be a specific material, but generally, a silicone oil, a mineral oil or the like having a relatively low viscosity is used. Furthermore, it is possible to prevent the hot offset phenomenon from occurring by the oilless fixing method without replenishing oil.

  Reference numeral 23a denotes a blade stopper, 23b denotes a blade holder, 24 denotes an ID unit, and 25 denotes a toner cartridge as a developer cartridge that accommodates the toner 16.

  By the way, in order to elucidate the reason why the developing blade filming generated on the developing blade 17 and the photosensitive drum filming generated on the photosensitive drum 11 occur, observation with an electron micrograph (hereinafter referred to as “SEM observation”). As a result of observation and analysis by elemental analysis, infrared absorption analysis (hereinafter referred to as “IR analysis”), etc., the following was found. The developing blade filming and the photosensitive drum filming have the same generation mechanism. First, an external additive adheres to the surface of the developing blade 17 or the surface of the photosensitive drum 11, and then the base toner. It has been found that the developer body particles are fused onto this. This is because a large amount of silica was observed by SEM observation, and the peak of silicon indicating the presence of silica relative to the peak intensity of carbon indicating the presence of developer main body particles by elemental analysis, IR analysis, etc. The intensity ratio was several tens of times larger than the ratio obtained from the toner used in the experiment, and a relatively large amount of developer main body particles were observed on the outermost surface. It was found that only silica was observed at a position closest to the surface of the developing blade 17 or the surface of the photosensitive drum 11.

Further, when only a developer main body particle to which no external additive was added was used as a toner and a comparative test was performed, filming was not observed even after printing 30000 sheets. Further, when the same experiment was performed using a toner having a viscosity of 1 × 10 ⁶ [poise] at 105 [° C.], filming occurred, but the number of printed sheets increased several times. Further, in the SEM observation at this time, the outermost layer, that is, the toner on the outermost layer, was observed to have more unevenness than when the toner of 1 × 10 ⁴ [poise] was used.

  Thus, it can be seen that when no external additive is added, toner having a high viscosity and low fluidity is used, filming is relatively difficult to occur or the number of printed sheets until the occurrence is increased. That is, an external additive adheres to or adheres to the surface of the developing blade 17 or the surface of the photosensitive drum 11 to form a base on which filming is likely to occur. It has been found that filming occurs by being melted by the above method. Further, it can be seen from the following that the degree of filming varies significantly depending on the printing duty.

  That is, a certain amount of a floating external additive (hereinafter referred to as “floating external additive”) exists in the toner to which the external additive is added. Therefore, in printing with a high printing duty, a large amount of toner is consumed, and therefore the amount of toner passing through the developing blade 17 is large. In proportion to this, the amount of the floating external additive passing through the developing blade 17 also increases, so that developing blade filming is likely to occur. On the other hand, in printing with a relatively low printing duty, a certain amount of toner on the developing roller 14 stays in the vicinity of the developing roller 14, and the toner supply roller 15, developing roller 14, developing blade 17, etc. Since the floating external additive is reliably adhered to the developer main body particles, the occurrence of developing blade filming can be suppressed.

  Photosensitive drum filming can be similarly interpreted. In printing with a high printing duty, the amount of residual toner in the same number of printings is larger than in printing with a low printing duty. As a result, the amount of residual toner that passes through the cleaning device 19 increases, and external additives having a particle size smaller than that of the developer main body particles are not cleaned, and a part of them adheres to the surface of the photosensitive drum 11. End up. Then, the toner particles are caught by the external additive fixed on the surface of the photosensitive drum 11 and melted to form photosensitive drum filming. If the cleaning device 19 is removed, the photosensitive drum filming does not occur, so that the above interpretation can be said to be appropriate.

  By the way, in the manufacturing process of the toner 16, when an external additive is added in the final process, the external additive is attached to the surface of the developer main body particles with high energy by an external addition device such as a Henschel mixer. , Some will remain alone. The external additive remaining alone was confirmed to be about 0.5 to 1% of the addition amount by simple measurement.

For example, if 1 [%] of the external additive is added to the developer main body particles, and 0.5 [%] of this remains alone, the external additive is 1 × with respect to the developer main body particles. An extremely small amount of ^10-5 parts by weight remains. However, the most commonly used external additive is much smaller than the developer main body particles, and the size is about 6 to 40 [nm]. On the other hand, since the size of the developer main body particles is several [μm], the remaining amount of the external additive cannot be ignored from the viewpoint of the number. Therefore, it is fully conceivable that filming occurs only when a very part of them adheres to or adheres to the developing blade 17 or the photosensitive drum 11.

  Therefore, in the present embodiment, the following method has been tried in order to prevent the occurrence of filming by removing the floating external additive.

  The first method is a method in which an external additive is added before the step for obtaining the particle size of the toner. When a pulverized toner is used as the toner, the pulverization usually includes coarse pulverization and fine pulverization, and the particle diameter of the product toner is obtained by fine pulverization. In the first method, an external additive is added after coarse pulverization and before fine pulverization.

In this case, the external additive is strongly attached to the surface of the developer main body particles by the energy given in the subsequent fine pulverization step. Even if the floating external additive remains, the floating external additive that is extremely smaller than the particle size of the toner as a product is removed in the classification step subsequent to the fine pulverization step. The floating external additive in this toner was 1 × 10 ⁻⁶ parts by weight, which was a fraction of that of a toner prepared by a usual method. When a durable printing test was performed using this toner, neither development blade filming nor photosensitive drum filming occurred even after printing 50,000 sheets, and an extremely good printed matter was stably obtained. I was able to.

The second method is a method in which fine pulverization is performed by an ordinary method, and in the classification step subsequent to the fine pulverization step, an external additive that is extremely smaller than the particle size of the toner as a product is removed. In this case, the amount of the floating external additive was 1 × 10 ⁻⁶ parts by weight, which was 1/10 of the toner prepared by a usual method. When a durable printing test was performed using this toner, neither development blade filming nor photosensitive drum filming occurred even when printing on 50,000 sheets, and an extremely good printed matter was stably obtained. I was able to.

  Next, examples and comparative examples of the toner of the present invention will be described.

  FIG. 3 is a first diagram illustrating each example and comparative example in the embodiment of the present invention, FIG. 4 is a second diagram illustrating each example and comparative example in the embodiment of the present invention, and FIG. It is a 3rd figure which shows each Example and comparative example in embodiment of invention.

  3 to 5, the composition of the mixture, the content of the pretreatment before the addition of the external additive, the composition of the external additive, the content of the posttreatment after the addition of the external additive, in the toner 300 [g] The amount of the floating external additive, the amount of the external additive released from the developer main body particles, the filming occurrence state, the print blurring occurrence state, and the comprehensive judgment are shown. All the parts are parts by weight. Moreover, in comprehensive judgment, (circle) represents favorable, (triangle | delta) is a little good, and x represents defect. The liberation amount is the ratio of the amount of the floating external additive to the 300 g toner to be inspected, and represents the weight part with respect to the developer main body particles.

  In each embodiment, the external additive is added in an amount of 0.2 parts by weight or more based on the developer main body particles.

[Example 1]
100 parts by weight of polyester resin (number average molecular weight Mn = 3700, glass transition point Tg = 62 [° C.]) as resin, 4.5 parts by weight of phthalocyanine blue as colorant, and 2.5 parts by weight of charge control agent The mixture having the composition of the above was sufficiently stirred (stirred) with a Henschel mixer, kneaded, heated and melted at a temperature of 120 [° C.] for about 3 hours with a roll mill, cooled to room temperature, Coarse pulverization was performed to obtain particles (coarse powder) having a particle diameter of about 1 [mm], that is, a chip serving as developer main body particles.

  To the obtained chip, silica having 1 part by weight of R972 (manufactured by Nippon Aerosil Co., Ltd.) and 1 part by weight of RX50 (manufactured by Nippon Aerosil Co., Ltd.) was added. In addition, the particle size of silica is made smaller than the particle size of the chip.

The chips to which silica is added are pulverized (fine pulverized) again using a collision plate type pulverizer “Dispersion Separator” (manufactured by Nippon Pneumatic Industrial Co., Ltd.), and particles obtained by pulverization (fine powder) ) To obtain a toner having an average particle diameter of 8 [μm]. Next, the toner 300 [g] was sieved using a sieve made of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a slight white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was the silica used as the external additive, and it was confirmed by SEM observation that the silica alone formed an aggregate and formed a floating external additive. . The amount of the floating external additive at this time was 8.1 [mg], and the free amount was 2.7 × 10 ⁻⁵ .

  Using this toner as the toner 16 of the image forming apparatus shown in FIG. 1, a durable printing test was performed in which a solid image (printing duty is 100%) was continuously printed on an A4 size paper 22.

  Even if printing is continuously performed on 50,000 sheets of paper 22, the image quality is not different from the initial one, printing can be performed with a sufficient print density, fogging occurs, and development blade filming is performed. There was no occurrence of white streaks or the like in the printing direction due to the above.

Further, when the photosensitive drum 11 was observed, the film thickness was reduced by about 4 [μm] from the initial one due to wear, but no photosensitive drum filming occurred.
[Example 2]
Polyester resin (number average molecular weight Mn = 3700, glass transition point Tg = 62 [° C.]) is 100 parts by weight, phthalocyanine blue as a colorant is 4.5 parts by weight, and charge control agent is 2.5 parts by weight. The mixture is sufficiently stirred and kneaded by a Henschel mixer, heated and melted at a temperature of 120 [deg.] C. for about 3 hours by a roll mill, cooled to room temperature, and the obtained kneaded product is then mixed using the collision plate pulverizer. This was pulverized and classified to obtain a chip as developer main body particles having an average particle diameter of 8 [μm].

  Silica containing 1 part by weight of R972 and 1 part by weight of RX50 was added to the obtained chip. In addition, the particle size of silica is made smaller than the particle size of the chip.

  Next, the chip to which silica was added was stirred for 120 seconds at 3000 [r / min] using a Henschel mixer. Then, the collision plate type pulverizer was used again, and classification was performed again while maintaining the classification condition at 8 [μm] to obtain the toner of this example.

Next, the toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a slight white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was the silica used as the external additive, and it was confirmed by SEM observation that the silica alone formed an aggregate and formed a floating external additive. . The amount of the floating external additive at this time was 6.5 [mg], and the free amount was 2.2 × 10 ⁻⁵ .

  Using this toner as the toner 16 of the image forming apparatus shown in FIG. 1, a durable printing test was performed in which a solid image (printing duty is 100%) was continuously printed on an A4 size paper 22.

  Even if printing is continuously performed on 50,000 sheets of paper 22, the image quality is not different from the initial one, printing can be performed with a sufficient print density, fogging occurs, and development blade filming is performed. There was no occurrence of white streaks or the like in the printing direction due to the above.

Further, no photosensitive drum filming occurred.
Example 3
In this example, a toner was prepared in the same manner as in Example 1 except that R972 was 1.5 parts by weight and RX50 was 1.5 parts by weight.

The toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a slight white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was the silica used as the external additive, and it was confirmed by SEM observation that the silica alone formed an aggregate and formed a floating external additive. . The amount of the floating external additive at this time was 12.0 [mg], and the free amount was 4.0 × 10 ⁻⁵ .

  Using this toner as the toner 16 of the image forming apparatus shown in FIG. 1, a durable printing test was performed in which a solid image (printing duty is 100%) was continuously printed on an A4 size paper 22.

  Even if printing is continuously performed on 50,000 sheets of paper 22, the image quality is not different from the initial one, printing can be performed with a sufficient print density, fogging occurs, and development blade filming is performed. There was no occurrence of white streaks or the like in the printing direction due to the above.

Further, no photosensitive drum filming occurred.
Example 4
100 parts by weight of polyester resin (number average molecular weight Mn = 3700, glass transition point Tg = 62 [° C.]), 4.5 parts by weight of phthalocyanine blue as a colorant, 2.5 parts by weight of charge control agent, polyethylene wax A mixture of 6.0 parts by weight of “SP-105” (manufactured by Sazol) was sufficiently stirred and kneaded with a Henschel mixer and then heated and melted at a temperature of 120 ° C. for about 3 hours with a roll mill. Then, the obtained kneaded product was coarsely pulverized to obtain a chip as developer main body particles having a particle size of about 1 [mm]. Silica containing 1 part by weight of R972 and 1 part by weight of RX50 was added to the obtained chip. In addition, the particle size of silica is made smaller than the particle size of the chip.

Next, the chip to which silica was added was pulverized (finely pulverized) again using the collision plate pulverizer and classified to obtain a toner having an average particle diameter of 8 [μm]. Then, the toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a slight white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was the silica used as the external additive, and it was confirmed by SEM observation that the silica alone formed an aggregate and formed a floating external additive. . The amount of the floating external additive at this time was 7.5 [mg], and the free amount was 2.5 × 10 ⁻⁵ .

  Using this toner as the toner 16 of the image forming apparatus shown in FIG. 1, a durable printing test was performed in which a solid image (printing duty is 100%) was continuously printed on an A4 size paper 22.

  Even if printing is continuously performed on 50,000 sheets of paper 22, the image quality is not different from the initial one, printing can be performed with a sufficient print density, fogging occurs, and development blade filming is performed. There was no occurrence of white streaks or the like in the printing direction due to the above.

Further, no photosensitive drum filming occurred.
Example 5
In this example, a toner was prepared in the same manner as in Example 4 except that R972 was changed to 0.5 part by weight and RX50 was changed to 0.5 part by weight.

The toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a slight white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was the silica used as the external additive, and it was confirmed by SEM observation that the silica alone formed an aggregate and formed a floating external additive. . The amount of the floating external additive at this time was 2.9 [mg], and the free amount was 9.7 × 10 ⁻⁶ .

  Using this toner as the toner 16 of the image forming apparatus shown in FIG. 1, a durable printing test was performed in which a solid image (printing duty is 100%) was continuously printed on an A4 size paper 22.

  Even if printing is continuously performed on 50,000 sheets of paper 22, the image quality is not different from the initial one, printing can be performed with a sufficient print density, fogging occurs, and development blade filming is performed. There was no occurrence of white streaks or the like in the printing direction due to the above.

Further, no photosensitive drum filming occurred.
Example 6
In this example, instead of R972 and RX50, aluminum oxide C (CAS # 1344-28-1 manufactured by Nippon Aerosil Co., Ltd.) was 1.0 part by weight, and T805 (manufactured by Nippon Aerosil Co., Ltd.) was 1.0 part by weight. Other than that, a toner was prepared in the same manner as in Example 4.

The toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a slight white aggregate was visually confirmed. According to IR analysis, it is confirmed that the aggregate is the aluminum oxide used as the external additive, and it is confirmed by SEM observation that the aluminum oxide alone forms an aggregate to form a floating external additive. It was done. The amount of the floating external additive at this time was 7.0 [mg], and the free amount was 2.3 × 10 ⁻⁵ .

  Using this toner as the toner 16 of the image forming apparatus shown in FIG. 1, a durable printing test was performed in which a solid image (printing duty is 100%) was continuously printed on an A4 size paper 22.

  Even if printing is continuously performed on 50,000 sheets of paper 22, the image quality is not different from the initial one, printing can be performed with a sufficient print density, fogging occurs, and development blade filming is performed. There was no occurrence of white streaks or the like in the printing direction due to the above.

Further, no photosensitive drum filming occurred.
Example 7
In this example, a toner was prepared in the same manner as in Example 1 except that R972 was 0.1 parts by weight and RX50 was 0.1 parts by weight.

The toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a slight white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was silica used as an external additive, and it was confirmed by SEM observation that the silica alone formed an aggregate and formed a floating external additive. . At this time, the amount of the floating external additive was 0.75 [mg], and the free amount was 0.75 × 10 ⁻⁶ .

  Using this toner as the toner 16 of the image forming apparatus shown in FIG. 1, a durable printing test was performed in which a solid image (printing duty is 100%) was continuously printed on an A4 size paper 22.

  Even if printing is continuously performed on 50,000 sheets of paper 22, the image quality is not different from the initial one, printing can be performed with a sufficient print density, fogging occurs, and development blade filming is performed. There was no occurrence of white streaks or the like in the printing direction due to the above.

Further, there was no occurrence of photoconductor drum filming in which toner, external additives and the like were fixed to the surface of the photoconductor drum 11. In the solid printing part, although it was very slight, the density unevenness such as fading occurred, and the degree of fading was almost constant before and after continuous printing.
Example 8
In this example, a toner was prepared in the same manner as in Example 1 except that R972 was 0.3 parts by weight and RX50 was 0.3 parts by weight.

The toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a slight white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was the silica used as the external additive, and SEM observation confirmed that the silica alone formed an aggregate to form a floating external additive. The amount of the floating external additive at this time was 15.5 [mg], and the free amount was 5.2 × 10 ⁻⁵ .

  Using this toner as the toner 16 of the image forming apparatus shown in FIG. 1, a durable printing test was performed in which a solid image (printing duty is 100%) was continuously printed on an A4 size paper 22.

  Printing was continuously performed on the paper 22, and a slight white streak occurred in the printing direction after passing 40000 sheets, and a slight fog was generated in proportion to this. Even when the printing of 50,000 sheets was completed, the white streak and the fogging level were hardly changed, and were slightly recognized visually.

  Further, when carefully viewing the printing results at this time, it has been found that printing omissions having a width of about 0.1 [mm] and a length of about 1 [mm] occur in the printing direction with a slight amount.

  Next, when the developing device was disassembled and SEM observation was performed on the developing blade 17, it was found that the toner was fused to the contact portion of the developing blade 17 with the developing roller 14. When the fused toner was carefully removed and SEM observation was performed again, an aggregate of silica alone was confirmed. The silicon peak by elemental analysis is significantly larger than the carbon peak indicating the presence of the developer main body particles, and is very close to the result of silica alone, so that it was found that the silica alone adhered to the developing blade 17. It was.

  In addition, observation of the photosensitive drum 11 confirmed that a large amount of white deposits having a width of about 0.1 [mm] and a length of about 1 [mm] adhered in the rotating direction. When the surface of the photosensitive drum 11 was measured with a surface roughness meter, it was found that the deposit had a protrusion of about 0.05 [mm].

  Next, SEM observation was performed on the surface of the photosensitive drum 11, and it was found that the toner was fused. According to the IR analysis, the ratio of the CH stretching absorption peak indicating the presence of developer main body particles to the SiO deformation absorption indicating the presence of silica was almost the same as that of the toner produced in this example.

  Next, when the fused toner was carefully removed, it was found that silica was fixed to the surface of the photosensitive drum 11 by SEM observation. Since the IR chart of this material is very similar to the IR chart of silica alone, it was found that the toner was fused after the silica first adhered (fixed) to the surface of the photosensitive drum 11.

From the above observation, it was found that the developing blade filming and the photosensitive drum filming occur by the same mechanism. Further, it has been found that the cause of the occurrence is the floating silica not attached to the toner.
Example 9
77.5 parts by weight of styrene as a resin, 22.5 parts by weight of acrylate-n-butyl, 1.5 parts by weight of low molecular weight polyethylene as an anti-offset agent, charge control agent “Eisenspiron Black TRH” ( A mixture of 2 parts by weight of Hodogaya Chemical Co., Ltd., 7 parts by weight of carbon black (Printex L Degussa) as a colorant, and 1 part by weight of 2,2′-azobisisobutyronitrile It was put into a lighter (“MA-01SC”, manufactured by Mitsui Miike Chemical Co., Ltd.) and dispersed at 15 [° C.] for 10 hours to obtain a polymerizable composition.

  In addition, 180 parts by weight of ethanol in which 8 parts by weight of polyacrylic acid and 0.35 parts by weight of divinylbenzene were dissolved were prepared, and 600 parts by weight of distilled water was added thereto to prepare a dispersion medium for polymerization. . The polymerizable composition was added to this dispersion medium, and dispersed for 10 minutes under the condition of 15 ° C. and 8000 revolutions by a TK homomixer (“M type”, manufactured by Tokushu Kika Kogyo Co., Ltd.).

  Next, the obtained dispersion was transferred into a 1 [liter] separable flask and reacted at 85 [° C.] for 12 hours while stirring at 100 [rpm] under a nitrogen stream. At this stage, the dispersoid obtained by the polymerization reaction of the polymerizable composition is referred to as intermediate particles.

  Subsequently, 9.25 parts by weight of methyl methacrylate and 0.75% by weight of acrylic acid-n-butyl were added to the aqueous suspension of the intermediate particles by an ultrasonic oscillator (US-150, Nippon Seiki Seisakusho Co., Ltd.). A water emulsion A comprising 0.5 parts by weight of 2,2′-azobisisobutyronitrile, 0.1 parts by weight of sodium lauryl sulfate, and 80 parts by weight of water was prepared. 9 parts by weight of the water emulsion A was dropped to swell the intermediate particles. Immediately after the addition, observation was made with an optical microscope. As a result, no emulsion droplets were observed, and it was confirmed that the swelling was completed in a very short time.

  Therefore, the reaction was carried out at 85 [° C.] for 10 hours as the second stage polymerization while continuing stirring under nitrogen. After cooling, the dispersion medium was dissolved with an aqueous 0.5N hydrochloric acid solution, filtered, washed with water, air-dried, and then dried under reduced pressure at 40 [° C.] for 10 hours and 10 [mmHg] to obtain developer main body particles. Next, silica having 1 part by weight of R972 and 1 part by weight of RX50 was added to the obtained developer main body particles.

Next, the chip to which silica was added was stirred for 120 seconds at 3000 [r / min] with a Henschel mixer, pulverized using a collision plate pulverizer, classified, and polymerized with an average particle size of 8 [μm]. A toner which is a toner was obtained. The amount of the floating external additive at this time was 8.0 [mg], and the free amount was 2.7 × 10 ⁻⁵ .

  Using this toner as the toner 16 of the image forming apparatus shown in FIG. 1, a durable printing test was performed in which a solid image (printing duty is 100%) was continuously printed on an A4 size paper 22.

  Even if printing is continuously performed on 50,000 sheets of paper 22, the image quality is not different from the initial one, printing can be performed with a sufficient print density, fogging occurs, and development blade filming is performed. There was no occurrence of white streaks or the like in the printing direction due to the above.

Further, no photosensitive drum filming occurred.
[Comparative Example 1]
A mixture of 100 parts by weight of a polyester resin (number average molecular weight Mn = 3700, glass transition point Tg = 62 [° C.]), 4.5 parts by weight of phthalocyanine blue, and 2.5 parts by weight of a charge control agent is a Henschel mixer. The mixture is sufficiently stirred and kneaded by using a roll mill, heated and melted at a temperature of 120 [deg.] C. for about 3 hours, cooled to room temperature, and the resulting kneaded product is pulverized using the impingement plate pulverizer. To obtain chips serving as developer main body particles having an average particle size of 8 [μm].

  Silica containing 1 part by weight of R972 and 1 part by weight of RX50 was added to the obtained chip. In addition, the particle size of silica is made smaller than the particle size of the chip.

  Next, the chip to which silica was added was stirred for 120 seconds at 3000 [r / min] with a Henschel mixer to obtain a toner comprising the pulverized toner of this comparative example.

Then, the toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a large amount of white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was the silica used as the external additive, and it was confirmed by SEM observation that the silica alone formed an aggregate and formed a floating external additive. . The amount of the floating external additive at this time was 40.5 [mg], and the free amount was 1.4 × 10 ⁻⁴ .

  Using this toner as the toner 16 of the image forming apparatus shown in FIG. 1, a durable printing test was performed in which a solid image (printing duty is 100%) was continuously printed on an A4 size paper 22.

  Printing was continuously performed on the paper 22, and white streaks occurred in the printing direction after passing 1000 sheets, and fogging occurred in proportion to this. Since the white streaks deteriorated as the number of printed sheets increased, the durability printing test was stopped at 2000 sheets.

  Further, when carefully viewing the printing results at this time, it was confirmed that there were very many missing prints with a width of about 0.1 [mm] and a length of about 1 [mm] in the printing direction.

  Next, when the developing device was disassembled and SEM observation was performed on the developing blade 17, toner fusion was observed at the contact portion of the developing blade 17 with the developing roller 14. When the fused toner was carefully removed and SEM observation was performed again, an aggregate of silica alone was confirmed. The silicon peak by elemental analysis was significantly larger than the carbon peak indicating the presence of the developer main body particles, and was close to the result of silica alone, indicating that the silica alone adhered to the developing blade 17.

  In addition, observation of the photosensitive drum 11 confirmed that a large amount of white deposits having a width of about 0.1 [mm] and a length of about 1 [mm] adhered in the rotating direction. When the surface of the photosensitive drum 11 was measured with a surface roughness meter, it was found that the deposit had a protrusion of about 0.05 mm.

  Next, SEM observation was performed on the surface of the photosensitive drum 11, and it was found that the toner was fused. According to IR analysis, the ratio of the CH stretching absorption peak indicating the presence of developer main body particles to the SiO deformation absorption indicating the presence of silica was almost the same as that of the toner prepared in this comparative example.

  Next, when the fused toner was carefully removed, it was found that silica was fixed to the surface of the photosensitive drum 11 by SEM observation. Since the IR chart of this material is very similar to the IR chart of silica alone, it was found that the toner was fused after the silica first adhered (fixed) to the surface of the photosensitive drum 11.

From the above observation, it was found that developing blade filming and photoconductor drum filming occurred. Further, it was found that the cause of the occurrence is floating silica that is not fixed to the toner.
[Comparative Example 2]
In this comparative example, a toner was prepared in the same manner as in Comparative Example 1 except that instead of R972 and RX50, 1.0 part by weight of aluminum oxide C and 1.0 part by weight of T805 were used.

Next, the toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a large amount of white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was titanium oxide used as an external additive, and SEM observation confirmed that titanium oxide alone formed an aggregate and formed a floating external additive. It was. The amount of the floating external additive at this time was 35.6 [mg], and the free amount was 1.2 × 10 ⁻⁴ .

  Using this toner as the toner 16 of the image forming apparatus shown in FIG. 1, a durable printing test was performed in which a solid image (printing duty is 100%) was continuously printed on an A4 size paper 22.

  Printing was continuously performed on the paper 22, and white streaks occurred in the printing direction from about 500 sheets, and fogging occurred in proportion to this. Since the white streaks deteriorated as the number of printed sheets increased, the durability printing test was stopped at 2000 sheets.

  Further, when carefully viewing the printing results at this time, it was confirmed that there were very many missing prints with a width of about 0.1 [mm] and a length of about 1 [mm] in the printing direction.

  Next, when the developing device was disassembled and SEM observation was performed on the developing blade 17, toner fusion was observed at the contact portion of the developing blade 17 with the developing roller 14. When the fused toner was carefully removed and SEM observation was performed again, an aggregate of titanium oxide alone was confirmed. The peak of titanium by elemental analysis was significantly larger than the carbon peak indicating the presence of the developer main body particles, and was close to the result of titanium oxide alone, indicating that titanium oxide alone adhered to the developing blade 17. .

  In addition, observation of the photosensitive drum 11 confirmed that a large amount of white deposits having a width of about 0.1 [mm] and a length of about 1 [mm] adhered in the rotating direction. When the surface of the photosensitive drum 11 was measured with a surface roughness meter, it was found that the deposit had a protrusion of about 0.05 [mm].

  Next, SEM observation was performed on the surface of the photosensitive drum 11, and it was found that the toner was fused. Then, when the fused toner was carefully removed, it was found that the titanium oxide was fixed to the surface of the photosensitive drum 11 by SEM observation. Since the IR chart of this substance is very similar to the IR chart of titanium oxide alone, it was found that the toner was fused after the titanium oxide first adhered (fixed) to the surface of the photosensitive drum 11.

From the above observations, it was found that developing blade filming and photosensitive drum filming occur even when an external additive other than silica is used. Further, as in the case of silica, it has been found that the developing blade filming and the photosensitive drum filming occur by the same mechanism.
[Comparative Example 3]
A toner was prepared in the same manner as in Comparative Example 1 except that R972 was changed to 0.5 parts by weight and RX50 was changed to 0.5 parts by weight.

Next, the toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a large amount of white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was silica used as an external additive, and it was confirmed by SEM observation that the silica alone formed an aggregate and formed a floating external additive. . The amount of the floating external additive at this time was 20.5 [mg], and the free amount was 6.8 × 10 ⁻⁵ .

  This toner was used as the toner 16 of the image forming apparatus shown in FIG. 1, and printing was performed to continuously print solid images (printing duty is 100%) on A4 size paper 22.

  Printing was continuously performed on the paper 22, and white streaks occurred in the printing direction from about 500 sheets, and fogging occurred in proportion to this. Since the white streaks deteriorated as the number of printed sheets increased, the durability printing test was stopped at 2000 sheets.

Further, when carefully viewing the printing results at this time, it was confirmed that there were very many missing prints with a width of about 0.1 mm and a length of about 1 mm in the printing direction. It was found that both body drum filming occurred.
[Comparative Example 4]
A toner was prepared in the same manner as in Comparative Example 1 except that R972 was 0.4 parts by weight and RX50 was 0.4 parts by weight.

Next, the toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a large amount of white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was the silica used as the external additive, and it was confirmed by SEM observation that the silica alone formed an aggregate and formed a floating external additive. . The amount of the floating external additive at this time was 17.0 [mg], and the free amount was 5.7 × 10 ⁻⁵ .

  This toner was used as the toner 16 of the image forming apparatus shown in FIG. 1, and printing was performed to continuously print solid images (printing duty is 100%) on A4 size paper 22.

  Printing was continuously performed on the paper 22, and white streaks occurred in the printing direction from about 500 sheets, and fogging occurred in proportion to this. Since the white streaks deteriorated as the number of printed sheets increased, the durability printing test was stopped at 2000 sheets.

Further, if the print sample at this time is carefully observed, it is confirmed that there are very many missing prints with a width of about 0.1 mm and a length of about 1 mm in the printing direction. It was found that both body drum filming occurred.
[Comparative Example 5]
A toner was prepared in the same manner as in Comparative Example 1 except that RX50 was changed to 0.1 parts by weight.

Next, the toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a very small amount of white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was silica used as an external additive, and it was confirmed by SEM observation that the silica alone formed an aggregate and formed a floating external additive. . The amount of the floating external additive at this time was 2.0 [mg], and the free amount was 6.7 × 10 ⁻⁶ .

  This toner was used as the toner 16 of the image forming apparatus shown in FIG. 1, and printing was performed to continuously print solid images (printing duty is 100%) on A4 size paper 22.

  Even when printing was continuously performed on 50,000 sheets of paper 22, no fogging occurred, and no white streaks or the like in the printing direction due to developing blade filming occurred.

  Further, there was no occurrence of photoconductor drum filming in which toner, external additives and the like were fixed to the surface of the photoconductor drum 11.

However, the solid print portion had a density unevenness that was faint than the initial printing, and the average print density was also less than 1.0. It has been found that this is caused by the fact that the toner is not sufficiently supplied onto the developing roller 14 because the amount of silica added is small and the fluidity is low.
[Comparative Example 6]
In the same manner as in Example 9, 1 part by weight of R972 and 1 part by weight of RX50 were added to the developer main body particles obtained in Example 9.

  Next, this mixture was stirred at 3000 [r / min] for 120 seconds with a Henschel mixer to obtain a toner which is a polymerized toner of this comparative example.

The toner 300 [g] was sieved using a sieve composed of a mesh having an opening of 45 [μm]. When the residue on the sieve was washed with ethanol to remove the toner particles, a large amount of white aggregate was visually confirmed. According to IR analysis, it was confirmed that the aggregate was silica used as an external additive, and it was confirmed by SEM observation that the silica alone formed an aggregate and formed a floating external additive. . The amount of the floating external additive at this time was 40.1 [mg], and the free amount was 1.3 × 10 ⁻⁴ .

  This toner was used as the toner 16 of the image forming apparatus shown in FIG. 1, and printing was performed to continuously print solid images (printing duty is 100%) on A4 size paper 22.

  Printing was continuously performed on the paper 22, and white streaks occurred in the printing direction from about 500 sheets, and fogging occurred in proportion to this. Since the white streaks deteriorated as the number of printed sheets increased, the durability printing test was stopped at 2000 sheets.

  Further, when carefully viewing the printing results at this time, it was confirmed that there were very many missing prints with a width of about 0.1 mm and a length of about 1 mm in the printing direction. It was found that both body drum filming occurred.

  In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

1 is a conceptual diagram of an electrophotographic image forming apparatus according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of a developer cartridge in the embodiment of the present invention. It is a 1st figure which shows each Example and comparative example in embodiment of this invention. It is a 2nd figure which shows each Example and comparative example in embodiment of this invention. It is a 3rd figure which shows each Example and comparative example in embodiment of this invention.

Explanation of symbols

11 Photosensitive drum 12 Charging roller 13 LED head 14 Developing roller 15 Toner supply roller 16 Toner 17 Developing blade 25 Toner cartridge

Claims (1)

(A) a step of kneading the resin and the colorant;
(B) a step of coarsely crushing a kneaded product composed of a kneaded resin and a colorant;
(C) adding an external additive to the developer main body particles obtained by coarse pulverization;
(D) a step of finely pulverizing the developer main body particles to which the external additive is added;
(E) a step of classifying the finely pulverized particles, and a method for producing a developer.

Images