JP2002082476A - Method for manufacturing electrostatic image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a toner which is little in environmental dependence and can form a high quality image even under a high temperature and high humidity environment. SOLUTION: The method includes a process of pulverizing and classifying a composition containing polyester resin and coloring agent to produce toner particles and a process of adding silicone oil to the toner particles. The polyester resin preferably has 10 to 50 mgKOH/g acid value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a toner for developing an electrostatic image, and more particularly to a method for producing a toner for developing an electrostatic image, which makes it possible to produce a toner having little environmental dependency.

[0002]

2. Description of the Related Art Generally, image formation by an electrophotographic system is performed by developing an electrostatic latent image with toner to visualize the image, and transferring the toner image obtained by the development to a sheet. The toner used for such image formation is usually manufactured by pulverizing and classifying a composition containing a binder resin and a colorant.

As a binder resin used for a toner, a polyester resin having excellent transparency is used particularly for forming a multicolor image. However, since the polyester resin has a hydrophilic group,
The moisture resistance is low, and the chargeability of the toner is reduced. Therefore, when an image is formed using a toner containing a polyester resin as a binder resin, fogging occurs particularly under high temperature and high humidity, and a high quality image cannot be obtained.

On the other hand, fine silica powder has been added to the toner in order to impart fluidity and uniform chargeability to the toner. However, since the fine silica powder has a hydrophilic property, moisture in the air is reduced. As a result, the toner is aggregated and the chargeability is reduced.

In order to solve such a problem, it has been proposed to add hydrophobic fine silica powder to the toner. For example, Japanese Patent Publication No. 7-120068 describes that as an external additive of a toner, silica treated with hexamethyldisilazane (HMDS) and further subjected to a spraying treatment with dimethyl silicone oil is added. Have been.

Japanese Patent Publication No. Hei 7-113783 discloses a method in which a silica fine powder treated with a silane coupling agent and then treated with various silicone oils is used as an external additive of the toner. Have been.

However, even if the silica fine powder subjected to the hydrophobic treatment is used, its effect is insufficient.
In particular, under high-humidity conditions, it was impossible to prevent a decrease in the chargeability of the toner.

[0008] In recent years, small and inexpensive copiers and printers have been sold and used in ordinary homes. Under such circumstances, under normal temperature and normal humidity,
It is desired to obtain high quality images even under various environments such as high temperature and high humidity and low temperature and low humidity.

[0009]

As described above, heretofore, there has been proposed a toner to which silica which has been hydrophobized by various processing methods using various processing agents is externally added. But,
Even with such a toner, it was insufficient to solve the deterioration of image quality under high temperature and high humidity. That is, even when a toner externally added with hydrophobic silica is used, such a toner has poor transferability. For example, when printing 6,000 sheets, voids (white background due to untransferred toner) are generated in a solid portion,
Fog occurs under high temperature and high humidity.

[0010] The present invention has been made under such circumstances,
It is an object of the present invention to provide a method for producing a toner for developing an electrostatic image, which is less dependent on the environment and can form a high-quality image even under high temperature and high humidity.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention comprises a step of pulverizing and classifying a composition containing a polyester resin and a colorant to form toner particles; Provided is a method for producing a toner for developing an electrostatic image, which comprises a step of adding oil.

In the electrostatic image developing toner of the present invention, the polyester resin used as the binder resin is 10 to 5
Desirably, it has an acid value of 0 mgKOH / g. If a polyester resin having an acid value outside this range is used, it tends to be difficult to obtain a high-quality image. In particular, a polyester resin having a softening point of 70 to 150 ° C synthesized from a diol and a polyvalent carboxylic acid can be suitably used in the present invention because it has high transparency.

In the present invention, the silicone oil added to the toner particles is selected from the group consisting of dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl-modified silicone oil, and fluorine-modified silicone oil. The selected one can be used.

It is desirable that the silicone oil has a kinematic viscosity of 1 to ²⁰ cm ² / s. If a silicone oil outside this range is used, spots may appear on the image.

The amount of silicone oil added is
0.02 to 1.4 parts by weight with respect to 0 parts by weight,
More preferably, it is 0.05 to 1.0 part by weight. If the amount of the silicone oil is less than 0.02 parts by weight, it is difficult to obtain the effect of the addition of the silicone oil.
When the amount exceeds the weight part, the toner tends to aggregate and white streaks tend to occur.

A known charge control agent may be added to the electrostatic image developing toner according to the present invention, if necessary. As the charge control agent, for example, in order to obtain a positively chargeable toner, a quaternary ammonium salt or a salt forming compound thereof,
In order to obtain a negatively charged toner, a metal complex or a metal complex salt of salicylic acid or alkyl salicylic acid, a boron-containing potassium salt compound, and the like are preferable. The addition amount of these charge control agents is preferably in the range of 0.01 to 20 parts by weight based on 100 parts by weight of the toner.

Further, various kinds of waxes may be added to the electrostatic image developing toner according to the present invention as a releasing agent for improving thermal characteristics. The toner of the present invention contains 0.01 to 5 inorganic oxide fine particles such as silica, titania and alumina as a fluidity improver per 100 parts by weight of the toner.
You may add in the range of a weight part.

The toner for developing an electrostatic image according to the present invention is used as a one-component developer. In some cases, the toner may be mixed with a carrier and used as a two-component developer.

The electrostatic image developing toner according to the present invention can be manufactured by various manufacturing methods. Generally, it can be manufactured by the following manufacturing method. First, a resin, a colorant, and if necessary, a charge control agent, a wax, a fluidity improver, and the like are uniformly mixed by a Henschel mixer or the like. Next, the mixture is melt-kneaded using a kneader, an extruder, a roll mill or the like.

Next, the kneaded material is roughly pulverized using a hammer mill, a cutter mill, or the like, and then finely pulverized using a jet mill, a single-type mill, or the like. Thereafter, the finely pulverized material is classified by a DS (dispersion classifier), a zigzag classifier or the like. The average particle size of the toner obtained by classification is preferably 3 to 18 μm.

Thereafter, a silicone oil is added to the classified toner particles to produce a toner. In some cases, silica may be further added to the toner using a Henschel Kimiser. The silica may be one whose surface has been subjected to a hydrophobic treatment using silicone oil or the like.

As described above, according to the method of the present invention, the moisture resistance of a toner is improved by adding silicone oil to toner particles and covering the surface of a polyester resin having low moisture resistance with silicone oil. Therefore, it is possible to manufacture a toner for developing an electrostatic image, which is less dependent on the environment and can form a high-quality image even under high temperature and high humidity.

Further, the toner produced by the method of the present invention contains silicone oil on the surface, and thus has excellent releasability, so that transferability is improved and an image having a high image density can be formed. is there. The reason why an image with a high image density can be formed is not always clear, but probably,
It is considered that part of the silicone oil migrated to the developing roller, thereby increasing the resistance value of the surface of the developing roll and increasing the amount of toner adhering to the surface of the developing roll.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, and the present invention will be described more specifically. FIG. 1 schematically shows an internal configuration of a color image forming apparatus suitable for forming an image using the toner manufactured according to the present invention. First, the overall configuration of the color image forming apparatus will be described with reference to FIG.

As shown in FIG. 1, the color image forming apparatus (main unit) 30 has an opening / closing tray 31 on its rear surface (left side in the figure) and a lower part from the front side (right side in the figure) of the main unit. A removable paper cassette 32 is provided. A large number of sheets are placed and stored in the sheet cassette 32.

The main unit 30 has an upper lid 33 on its upper surface. Although not shown in the drawing, a power switch, a liquid crystal display device, a plurality of input keys, and the like are provided on the front side of the upper lid 33. The upper lid 33 has a
A paper discharge tray 34 is formed together with the upper surface of the rear part 0.

A flat loop-shaped paper transport belt (hereinafter simply referred to as a belt) 35 is disposed substantially in the center of the main body device 30 so as to extend back and forth, and both ends of the loop in the horizontal direction are arranged. It is held by a driving roller 36 and a driven roller 37. The belt 35 is driven by a driving roller 36 and circulates in a counterclockwise direction indicated by an arrow R in the figure. Along the upper circulation portion of the belt 35, four photosensitive drums 38 (38a, 38b, 38c, 38d)
They are arranged in a multi-stage manner in the paper transport direction (from right to left in the figure).

These photosensitive drums 38 (38a, 38
b, 38c, 38d) (representatively, only the peripheral devices around the photoreceptor drum 38d are denoted by reference numerals) so as to surround the cleaner 41, the initialization charging roller 42, the writing head 43, and A developing device 44 (44d) is provided. Further, the contact type sheet transfer device 39 is
The transfer portion is formed by being pressed against the photosensitive drum 38 via the belt 35. The photosensitive drums 38a, 38b,
The developing devices 44a, 44b, 4
4c is arranged.

Developing device (developing hopper) 44 (44d)
Is provided with a developing roller 45 rotatably supported in the lower opening thereof. The developing roller 45 contacts the peripheral surface of the photosensitive drum 38 to form a developing unit. The write head 43 is disposed on the back surface of the upper lid 33 via a support member 46, moves up and down in an arc as the upper lid 33 opens and closes, descends when the upper lid 33 is closed, and initializes. It is positioned between the roller 42 and the developing roller 45 to form a recording unit.

At the upstream end of the upper circulation portion of the belt 35,
The suction roller 47 is driven by the driven roller 37 via the belt 35.
To form a paper carry-in section. The suction roller 47 presses the belt 35 while applying a suction bias to the sheet carried into the sheet carrying unit, and the belt 35
Paper is electrostatically attracted to the paper.

The photosensitive drum 3 at the uppermost stream in the paper transport direction
Each developing device from the developing device 44a for 8a to the developing device 44d corresponding to the photosensitive drum 38d has three primary colors of M (magenta), C (cyan), Y (yellow), and Bk (black), which are the subtractive primary colors. Each color toner is stored. Each of these toners is a toner produced by the method of the present invention and having little environmental dependency.

On the upstream side (right side in the drawing) of the belt 35 in the transport direction, a standby roll pair 48 and a paper feed guide path 49 are arranged below the standby roll pair 48. A roll pair 51 is provided. The paper feed end of the paper cassette 32 described above is located upstream (below) of the feed roll pair 51. A paper feed roller 52 is provided above the paper feed end of the paper cassette 32. The feed roller 52 is rotated every rotation.
The uppermost sheet contained in the sheet cassette 32 is taken out and fed to the feed roll pair 51.

On the other hand, a fixing device 53, a pair of paper discharge rolls 54, and a switching lever 55 are provided downstream of the belt 35 in the paper transport direction (left side in the drawing). The fixing device 53 includes a pressure contact roller, a fixing roller, a heating roller, a paper separating claw, a peripheral surface cleaner, an oil application member,
It is composed of a thermistor or the like, and heat-fixes the toner image transferred onto the paper to the paper surface.

When the switching lever 55 is at the lower position as shown in the figure, it guides the sheet to the discharge tray 34 via the upper discharge path 56 and the discharge roll pair 57. On the other hand, when rotating upward, the sheet is guided to the opening / closing tray 31 opened on the rear surface of the main unit.

Between the belt 35 and the paper cassette 32,
An electrical unit 58 on which a circuit board can be mounted is provided, and a control device including a plurality of electronic components is mounted on the circuit board.

The control unit comprises a controller unit and an engine unit. The controller unit is a CPU (central processing unit), ROM (read only memory), EEPROM (rewritable read memory), frame memory, image data transfer. It has a circuit and the like, analyzes print data input from a host computer or the like, creates print data, and transfers it to the engine unit.

The engine unit includes a CPU, a ROM, and the like.
On the input side, data and command signals from the controller unit, the output of the temperature sensor, the output of the paper detection sensor, etc. are input.On the output side, a motor driver that drives a motor (not shown) A clutch driver for switching the drive system to be transmitted, a print driver for driving the write head 43 based on the print data, an initialization charging roller 42, a developing roller 45, a transfer device, a suction roller 47,
A bias power supply driver or the like that supplies a predetermined bias voltage to a toner supply roller, a doctor blade, a developing unit scooping sheet, and the like, which will be described later, is connected. The engine unit controls the driving of each unit based on data and command signals from the controller unit, the output of the temperature sensor, the output of the sheet detection sensor, and the like.

Next, the color image forming apparatus 3 described above
The basic operation of 0 will be described. First, when the power is turned on and the paper quality, the number of sheets to be used, the print mode, and other designations are input as a key input or a signal from a host device to be connected, the paper feed roller 52 rotates one turn by a drive mechanism (not shown). Then, the paper stored in the paper cassette 32 is fed to the standby roll pair 48 via the feed roll pair 51. The standby roll pair 48 suspends the rotation, and waits for the transport timing in a state in which the leading end of the sheet abuts on a holding portion formed by a pair of rollers.

Subsequently, the driving roller 36 rotates counterclockwise, and the driven roller 37 is driven to rotate similarly in the counterclockwise direction. As a result, the belt 35 has four photosensitive drums 38a, 38b, 38c,
In contact with d, the whole circulates in the counterclockwise direction.

At the same time, the developing units 44a, 44b, 4
4c, 44d and photosensitive drums 38a, 38b, 38
c and 38d are sequentially driven in accordance with the printing timing. The photoconductor drum 38 rotates clockwise, the initialization charging roller 42 applies a uniform high negative charge to the peripheral surface of the photoconductor drum 38, and the writing head 42 applies Exposure is performed according to an image signal to form a low potential portion. As a result, an electrostatic latent image composed of a high negative potential portion due to the initialization and a low negative potential portion due to exposure is formed. The developing roller 45 of the developing device 44 transfers the toner to a low potential portion of the electrostatic latent image to form a toner image on the peripheral surface of the photosensitive drum 38 (reversal development).

At the timing when the leading end of the toner image on the peripheral surface of the most upstream photosensitive drum 38a is rotated and conveyed to the point facing the belt 35, the printing start position of the paper coincides with the point. Then, the standby roll pair 48 starts rotating and feeds the paper to the paper carry-in section.

The driven roller 37 and the suction roller 47 hold and transport the fed sheet together with the belt 35. The sheet is attracted to the belt 35 and transported to the first transfer section formed by the photosensitive drum 38a and the transfer device.

The transfer unit applies a transfer current output from a transfer bias power supply to a sheet via a belt 35. The transfer current applied from the transfer device causes the photosensitive drum 3
The M (magenta) toner image on 8a is transferred to the sheet. Subsequently, at the second transfer portion from the upstream formed by the photosensitive drum 38b and the transfer device, C (cyan)
Is transferred, and further the toner image of the third transfer portion Y (yellow) from the upstream formed by the photosensitive drum 38c and the transfer device is transferred. Then, a Bk (black) toner image is sequentially transferred at the most downstream transfer portion formed by the photosensitive drum 38d and the transfer device.

The paper on which the four color toner images have been transferred in this manner is separated from the belt 35 and carried into the fixing device 53. The fixing device 53 thermally fixes the toner image on the sheet. After the image is fixed, the paper is discharged by the discharge roll pair 54 with the toner image upward on the opening / closing tray 31 on the rear surface or the toner image downward on the upper discharge tray 34.

FIG. 2 is a side sectional view schematically showing a main part of the developing unit 44. The developing device 44 shown in FIG. 1 is detachable from the color image forming apparatus 30 and is a developing unit that forms one image forming unit together with the drum unit. The developing device 44 includes a housing 61 also serving as a toner hopper, and rotatably holds a developing roller 45 made of a conductive rubber roller at a lower opening of the housing 61.
Inside the housing 61, there is provided a toner stirring member 63 which accommodates the toner 62 and is disposed so as to be buried in the toner 62.

A supply roller 64 made of a sponge body is disposed at the lowermost part of the developing device 44 in pressure contact with the developing roller 45. The developing roller 45 is pressed against the obliquely upper right peripheral surface thereof by a metallic leaf spring-shaped doctor blade 65.
The developing unit scooping sheet (conductive regulation sheet) 66 is arranged in contact with the lower peripheral surface. The developing unit scooping sheet 66 is provided with a later-described conductive regulating sheet bias unit including a bias power supply 71. On both sides of the doctor blade 65, sealing members 67 for separating the inside and the outside of the opening of the housing 61 and preventing leakage of the toner 62 are provided.

By the way, in order to scrape off the toner 62 of the non-development portion remaining on the peripheral surface of the developing roller 45 after the development on the photosensitive drum 38 is completed, the toner 62 is scraped off in the housing 61 to eliminate the development memory. The required rubbing force of the supply roller 64 depends on the adhesion of the toner 62 to the developing roller 45. That is, a strong rubbing force is required for a toner having a strong adhesive force, but a weak rubbing force is sufficient for a toner having a weak adhesive force. The developing roller 45 of the toner 62
It can be said that the adhesive force to the toner is substantially determined by the charging ability of the toner 62. That is, the smaller the amount of triboelectric charge, the weaker the adhesive force, and thus the easier it is to scrape off the developing roller 45.

However, the amount of frictional charge of the toner 62 has a close relationship with adhesion development (hereinafter referred to as photoreceptor fogging) on a non-image portion which occurs during development and causes a problem, and the toner 62 has a small charge amount. The more the photoreceptor is fogged, the more likely it is. Therefore, in order to prevent such photoconductor fog from occurring, it is necessary to increase the triboelectric charge amount of the toner 62. When the frictional charge amount of the toner 62 is increased, the adhesive force to the developing roller 45 is increased.
4 needs to be given a strong rubbing force.

It is not preferable to repeat the rotation for a long time with such a strong rubbing force, because it causes deterioration of toner characteristics such as a decrease in toner charging ability and a decrease in fluidity. For example, when the charge amount is reduced, the above-described photoreceptor fogging is generated, and when the fluidity is reduced, the lack of development in halftone printing occurs.

In the developing device 44 having such a problem, in one embodiment of the present invention, first, the developing roller 45 is made of a metal core and a cylindrical semiconductive (10 ⁶ Ωcm) surrounding the metal core. ), And a developing bias of “−250 V” is applied to the core metal from a bias power supply 68. Further, the supply roller 64 is constituted by a core bar and a cylindrical semiconductive (10 ⁶ Ωcm) urethane sponge surrounding the core bar, and a supply bias of “−500 V” is applied to the core bar from the bias power supply 69. Apply.

Further, the doctor blade 65 is formed of an elastic metal plate, and a doctor bias of “−500 V” is applied to the doctor blade 65 from the bias power source 69. Then, the developing unit scooping sheet 66 located on the upstream side of the supply roller 64 is formed of a conductive member (10 ³ Ωcm), and a sheet in a range from 0 V (0 volt) to the developing bias voltage of the developing roller 45 is provided. A bias voltage is applied by a bias power supply 71.

As described above, the developing portion scooping sheet 66 is formed of a conductive member, and the sheet bias voltage in the range from 0 V to the developing bias voltage of the developing roller 45 is applied to the developing portion scooping sheet 66. This is to reduce the charge of the toner 62 attached. Thereby, the supply roller 6
4, the developing roller 45 can be easily rubbed by the weak rubbing force.
The non-developed portion of the toner that has adhered and returned has been scraped off.

In the developing device 44 shown in FIG.
For convenience, application of a developing bias voltage to the developing roller 45 is performed by a bias power supply 68, and application of a sheet bias voltage to the developing unit scooping sheet 66 is performed by a bias power supply 7.
Although described in the example in which the power supply is performed individually according to 1, the power supply does not need to be provided separately in this way. That is, in the actual developing unit configuration of the present invention, for example, a voltage dividing circuit including a resistance element is provided in the unit, and the bias voltage divided into each of the developing roller 45 and the developing unit scooping sheet 66 by the common bias power supply of the apparatus main body. A voltage is applied.

With the color image forming apparatus and the image forming process having the above-described apparatus configuration, the toner manufactured by the method of the present invention can be used in a high-temperature and high-humidity environment.
An image with excellent image quality can be formed.

[0055]

The present invention will be described in more detail with reference to the following examples showing the production of an electrostatic image developing toner by the method of the present invention. First, a production example of a binder resin used in each embodiment will be described.

Production Example 1 (Resin A) Polyoxypropoxypropylene (2,2) -2.2-bis (4-hydroxyphenyl) propane 1050 g Polyoxypropoxyethylene (2,2) -2.2-bis (4 -Hydroxyphenyl) propane 325 g Terephthalic acid 330 g Fumaric acid 240 g Hydroquinone 0.5 g Each of the above compounds was placed in a four-liter glass flask having a capacity of 2 liters, and a thermometer, a stainless steel stirring rod, a falling condenser and A nitrogen inlet tube was attached. Then, while flowing nitrogen in the electric heating mantle heater,
While stirring at 180 ° C. in the first half and 200 ° C. in the second half under reduced pressure, the reaction was carried out while tracking the acid value to produce a polyester. The acid value of the obtained polyester was 27.0 (mgK
OH / g).

Production Example 2 (Resin B) Polyoxypropoxypropylene (2,2) -2.2-bis (4-hydroxyphenyl) propane 840 g Polyoxypropoxyethylene (2,2) -2.2-bis (4 -Hydroxyphenyl) propane 195 g Terephthalic acid 249 g Fumaric acid 132 g 1,2,5-Pententricarboxylic acid 29 g Dibutyltin oxide 2 g Hydroquinone 0.5 g Using the same apparatus as in Production Example 1, the above compounds were formulated in the same manner. The reaction was performed while tracking the acid value. The acid value of the obtained polyester was 19.0 (mgKOH / g)
Met.

Production Example 3 (Resin C) Polyoxypropoxypropylene (2,2) -2.2-bis (4-hydroxyphenyl) propane 578 g Polyoxypropoxyethylene (2,2) -2.2-bis (4 -Hydroxyphenyl) propane 176 g Trimethylolpropane 72 g Isophthalic acid 472 g The above compounds were reacted in the same apparatus as in Production Example 1 and in the same formulation, while tracking the acid value. The acid value of the obtained polyester was 16.0 (mgKOH / g).
Met.

Production Example 4 (Resin D) Polyoxypropoxypropylene (2,2) -2.2-bis (4-hydroxyphenyl) propane 770 g Polyoxypropoxyethylene (2,2) -2.2-bis (4 -Hydroxyphenyl) propane 720 g Terephthalic acid 690 g Tri-n-ethylhexyl 1,2,4 benzenetricarboxylate 120 g The above compound was reacted using the same apparatus as in Production Example 1 with the same formulation, while tracking the acid value. Advanced. The acid value of the obtained polyester was 2.1 (mgKOH / g).

Example 1 Polyester resin (resin A: acid value 27.0 mg KOH
/ G) 100 parts by weight, a charge controlling agent (LR-147 manufactured by Nippon Carlit Co., Ltd.) 1.5 parts by weight, a polypropylene resin 2.0 parts by weight, and a coloring pigment (copper phthalocyanine: P)
ig. Blue 15: 3) 4.0 parts by weight were mixed in a Henschel mixer, melt-kneaded in a hot roll mill, cooled, coarsely ground using a hammer mill, then finely ground by an air jet method, and dispersed classification. Disperse in the machine,
A classified product having a particle size of 5 to 20 μm was obtained.

100 parts by weight of this classified product, dimethyl silicone oil (KF96-500c manufactured by Shin-Etsu Chemical Co., Ltd.)
s) (Kinematic viscosity 5 cm ² / s) 0.2 parts by weight, and silicon oxide fine powder (RX-50, manufactured by Nippon Aerosil Co., Ltd.)
5 parts by weight were further mixed with a Henschel mixer to obtain a blue toner.

When this blue toner was printed on a color printer (Color Page Press N4-612: manufactured by Casio) for 6,000 sheets, a good image output was obtained.

When printing was performed in a high-temperature, high-humidity environment of 32.5 ° C. and 80 RH%, a good image was obtained.

Example 2 As a polyester resin, resin B was used instead of resin A.
(Acid value: 19.0 mgKOH / g) A blue toner was produced in the same manner as in Example 1, except that the toner was changed to 19.0 mgKOH / g.

When this blue toner was printed by a color printer (Color Page Press N4-612: manufactured by Casio) for 6,000 sheets, a good image output was obtained.

When printing was performed in a high-temperature, high-humidity environment of 32.5 ° C. and 80 RH%, a good image was obtained.

Example 3 As a polyester resin, resin C was used instead of resin A.
(Acid value: 16.0 mgKOH / g) A blue toner was produced in the same manner as in Example 1, except that the toner was changed to 16.0 mgKOH / g.

When this blue toner was printed on a color printer (Color Page Press N4-612: manufactured by Casio) for 6,000 sheets, a good image output was obtained.

When printing was performed in a high-temperature, high-humidity environment of 32.5 ° C. and 80 RH%, a good image was obtained.

Example 4 Dimethyl silicone oil (KF96-500) was replaced with dimethyl silicone oil (KF96-200) (kinematic viscosity 2).
cm ² / s) in the same manner as in Example 1, except that
A blue toner was produced.

When this toner was printed on a color printer (Color Page Press N4-612: manufactured by Casio) for 6,000 sheets, a good image output was obtained.

When printing was performed in a high-temperature, high-humidity environment of 32.5 ° C. and 80 RH%, a good image was obtained.

Comparative Example 1 A blue toner was produced in the same manner as in Example 1 except that no dimethyl silicone oil was added. This toner is supplied to a color printer (Color Page Presto N4-61).
2: Casio Co., Ltd.), and an image having many voids was obtained in the solid portion.

When printing was performed in a high-temperature, high-humidity environment of 32.5 ° C. and 80 RH%, an image with much fog was found. From the comparison between Examples 1 to 4 and Comparative Example 1,
By adding silicone oil to toner particles,
It can be seen that the image characteristics under high humidity are clearly improved.

[0075] REFERENCE EXAMPLE 1 Dimethyl silicone oil (KF96-500, kinematic viscosity: 5cm ² / s) instead of dimethyl silicone oil (KF96-100, kinematic viscosity: 1cm ² / s), except for using the Example 1 A blue toner was produced in the same manner.

When this toner was printed with a color printer (Color Page Presto N4-612: manufactured by Casio), the image quality was good immediately after the start of use of the toner.
The printing gradually faded after printing 00 sheets. When the inside of the printer was inspected, it was found that the area around the fixing device was contaminated with silicone oil.

From the comparison between Examples 1 to 4 and this reference example, it is found that if the viscosity of the silicone oil is too low, the silicone oil is liable to be scattered, which is not preferable.

Reference Example 2 Example 1 was repeated except that dimethyl silicone oil (KF96-5000) (kinematic viscosity: 50 cm ² / s) was used instead of dimethyl silicone oil (KF 96-500, kinematic viscosity: 5 cm ² / s). A blue toner was produced in the same manner.

When this toner was printed with a color printer (Color Page Presto N4-612: manufactured by Casio), spots appeared on the image.

From the comparison between Examples 1 to 4 and this Reference Example, it is found that it is not preferable that the viscosity of the silicone oil is too high.

Reference Example 3 Resin A (acid value: 27.0 mg) was used as a polyester resin.
Resin D (2.1 mg KO) instead of KOH / g)
H / mg), except that the blue toner was manufactured in the same manner as in Example 1.

When this toner was printed with a color printer (Color Page Presto N4-612, manufactured by Casio), an image with extremely high fog was obtained.

From the comparison between Examples 1 to 4 and this reference example, good quality images can be obtained when the acid value of the polyester resin used as the binder resin of the toner is out of the range of 10 to 50 mgKOH / g. You can see that it can not be done.

[0084]

As described in detail above, according to the present invention, by adding silicone oil to toner particles, the releasability of the toner is increased, the transfer efficiency is improved, and the transfer of the polyester resin is improved. By sealing the hydrophilic carboxyl group as an end group with silicone oil, a stable image can be obtained at high temperature and high humidity.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an internal configuration of a color image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a side sectional view schematically showing a main part of a developing device of the color image forming apparatus of FIG.

[Explanation of symbols]

 Reference Signs List 30 color image forming apparatus 31 opening / closing tray 32 paper cassette 33 top cover 34 paper discharge tray 35 paper transport belt 36 driving roller 37 driven roller 38, 38a, 38b, 38c, 38d photosensitive drum 39 Sheet transfer unit 41 Cleaner 42 Initializing charging roller 43 Writing head 44a, 44b, 44c, 44d Developing unit.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ryo Fujisawa 4084 Miyadera, Iruma City, Saitama Prefecture Inside (72) Inventor Yoichi Tamagawa 4084 Miyadera, Iruma City, Saitama Prefecture Inside Casio Electronic Industry ( 72) Inventor Masahiro Maeda 4084 Miyadera, Iruma-shi, Saitama Prefecture Casio Electronics Co., Ltd. (72) Inventor Hiroki Furuya 4084 Miyadera, Iruma-shi, Saitama Prefecture Casio Electronics Co., Ltd.F-term (reference) 2H005 AA01 AA08 AB10 CA08 CA12 CA26 CB07 CB13 EA03 EA10

Claims (6)

[Claims] A step of pulverizing and classifying a composition containing a polyester resin and a colorant to form toner particles;
And a step of adding a silicone oil to the toner particles. 2. The method according to claim 1, wherein the polyester resin comprises 10 to 50 mg.
The method according to claim 1, wherein the toner has an acid value of KOH / g. 3. The silicone oil according to claim 1, wherein said silicone oil is selected from the group consisting of dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl-modified silicone oil, and fluorine-modified silicone oil. A method for producing a toner for developing an electrostatic image. 4. The silicone oil according to claim 1, wherein said silicone oil is 1 to 20 cm ² /
2. The method according to claim 1, wherein the toner has a kinematic viscosity of s. 5. The electrostatic image developing toner according to claim 1, wherein the addition amount of the silicone oil is 0.02 to 1.4 parts by weight based on 100 parts by weight of the toner particles. Production method. 6. The method for producing a toner for developing an electrostatic image according to claim 1, further comprising a step of adding an inorganic oxide.