JP2003043740A - Method for producing toner for developing electrostatic image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing toner for developing an electrostatic image in which pulverized toner separated in the case of a classifying stage in the production of the toner is reused as toner producing material without changing the setting of a condition for a producing stage as far as possible and the characteristics of the toner obtained by the above manner is excellent. SOLUTION: In a mixing stage in the production of the toner, at least binding resin, a colorant, an electrification control agent and a release agent are mixed by 1st mixing energy, and then the pulverized toner separated in the case of the previous classifying stage is added to the 1st mixture and mixed by 2nd mixing energy lower than the 1st mixing energy so as to obtain 2nd mixture. The obtained 2nd mixture is taken over to the kneading stage being the next one, and further to respective cooling-crushing-classifying stages, and the toner incorporating the pulverized toner is produced based on the respective stages. It is desirable to set the mixing rate of the pulverized toner in the 2nd mixture to 5 to 50 mass %.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a toner for electrostatic image development, and in particular, a toner material which is a main component of a product toner in a classification step and a fine powder toner which is separated from the toner material are reused as a toner manufacturing material. In particular, the present invention relates to a method for producing an electrostatic image developing toner, which can provide a product toner that does not impair toner characteristics.

[0002]

2. Description of the Related Art Image formation by an electrophotographic system is generally carried out by developing an electrostatic latent image with toner to make it visible and transferring the toner image obtained by the development onto a sheet. The toner for electrostatic image development used for such image formation is prepared by mixing, kneading and cooling various toner manufacturing materials such as a binder resin, a colorant, a charge control agent and a release agent, and once forming a plate or pellet. Solidified to the intermediate toner (material), and then the solidified intermediate toner (material) is pulverized and classified into a predetermined particle size by various pulverizers to obtain a toner (material) which is a main component of the product toner. If necessary, an external additive such as a fluidity improver is mixed with the final toner to manufacture the final toner.

In the classification step, a fine powder toner having a particle size not larger than a predetermined particle size different from that of the desired predetermined particle size causes defects such as toner scattering and so-called fog, which deteriorates the quality of the product. Therefore, I try to remove it after classifying and sorting. However, in this case, the fine powder toner is collected and accumulated every time the toner is manufactured, and if it is discarded as it is, the toner cost increases.

Therefore, if such a fine powder toner can be reused for producing a toner, the product yield is improved and the cost is reduced. Therefore, an attempt has been made to collect and recycle the fine powder toner. That is, as a conventionally known method for regenerating the fine powder toner, there is a method in which the fine powder toner recovered by the classification is directly returned to the normal toner manufacturing material mixing step to be regenerated. That is, the collected fine powder toners are put into a mixer at an appropriate ratio together with various toner manufacturing materials such as the above-mentioned binder resin and colorant, and they are collectively mixed and then put into a kneader.

By the way, the toner provided for electrostatic image development is required to have a toner charge amount in a stable and proper range at the time of image formation, and the toner scattering, fog, and
Further, toner characteristics such as fixing offset are required. Therefore, as described above, the charge control agent is added to the toner manufacturing material to stabilize the toner charge amount. However, the charge of the toner is extremely delicate, and even if the charge control agent is mixed in the binder resin, if the dispersion state is poor or unevenly distributed, the chargeability of each toner particle becomes unstable, and the image forming apparatus becomes unstable. Toner scattering, fusing roller contamination, or fog may occur. On the other hand, although the colorant is used for coloring the toner as described above, it is known that the dispersion state of the colorant in the toner greatly affects not only the coloring power but also the charging property of the toner. As a measure for preventing fixing offset, a release agent such as low softening point wax is used as a toner manufacturing material as described above, but this release agent is basically incompatible with the binder resin. for,
It is extremely important to properly adjust the dispersion state. Therefore, in each of the series of steps of mixing-kneading-cooling-grinding-classification in toner production, appropriate production process conditions are set according to the toner characteristics to be the product toner.

However, it has been conventionally proposed to return the fine powder toner recovered by the classification to the material mixing step as described above, and to regenerate it. However, the conventional fine powder toner regeneration method is suitable for that purpose. Since the manufacturing process conditions are not sufficiently taken into consideration, there is a problem to be solved that good toner characteristics cannot be obtained even when the toner is manufactured by reusing the fine powder toner by the above conventional method. .

That is, the above-mentioned binder resin, colorant, charge control agent and release agent which are generally added to the mixing step,
Not only the particle size and specific gravity of the recovered fine powder toner are significantly different, but the composition of the toner material and the fine powder toner, which are the main constituents of the product toner obtained in the classification step, are also different. If the manufacturing process conditions such as the mixing method set on the premise that no toner is used are used as they are, a mixing failure or the like is caused, and a toner having good characteristics cannot be manufactured.

Therefore, in order to use the fine powder toner, it is considered that the manufacturing process conditions corresponding thereto are required,
If the manufacturing process conditions are drastically changed to reuse the fine powder toner, the toner manufacturing process management becomes complicated, and the cost merit is reduced by half.

If only the particle size and specific gravity of the fine powder toner are taken into consideration, a new granulating machine may be introduced to increase the particle size of the fine powder toner, and the recovered fine powder toner may be returned to the mixing step through the granulating step. Although it is conceivable, there was the problem of cost increase due to the increase of equipment and facilities.

[0010]

SUMMARY OF THE INVENTION The present invention has been made under the above circumstances, and the setting of manufacturing process conditions is changed as much as possible for the fine powder toner separated from the toner material which mainly constitutes the product toner in the classification process. Electrostatic charge that can be reused as a toner manufacturing material without using the toner and that can form high-quality images with good chargeability without toner scattering, fog, and fixing offset even when reusing fine powder toner. An object of the present invention is to provide a method for producing an image developing toner.

[0011]

In order to achieve the above object, the inventors of the present invention have earnestly studied, and as a result, paying attention to the composition of the fine powder toner recovered, the mixing method among the manufacturing process conditions is The present invention has been completed by finding that the above problems can be solved by changing to.

That is, according to the present invention, a mixing step of mixing at least a binder resin, a colorant, a charge control agent and a release agent, and kneading the mixture obtained by the mixing step,
Each step of cooling, pulverizing and classifying is sequentially carried out, and a toner is manufactured by mixing an external additive as necessary with the toner material having a predetermined particle diameter obtained by the classifying step, while particles from the toner material are mixed. A method for producing an electrostatic image developing toner by recycling fine powder toner by recovering the fine powder toner classified as particles having a small diameter, and returning the collected fine powder toner to the mixing step. In the mixing step, at least the above-mentioned binder resin, colorant, charge control agent and release agent are first added.
And a second mixture lower than the first mixing energy by adding the recovered fine powder toner to the first mixture obtained by the first mixing step.
The second mixing step of mixing with the mixing energy of
The second mixture containing the fine powder toner obtained after the second mixing step is used in the next step, and the toner containing the fine powder toner is produced based on this. Further, in the above manufacturing method, 5 to 30 parts by mass of the recovered fine powder toner is added to 100 parts by mass of the first mixture.

According to such a method of the present invention, the recovered fine powder toner is added to the first mixture obtained by mixing with the first mixing energy, and the first mixture is added to the first mixture. Is mixed with a second mixing energy lower than the mixing energy of 2 to obtain a second mixture containing fine powder toner, and the second mixture is used in the next step.
The recovered fine powder toner is subjected to the next step in an appropriate dispersed state, and as a result, it is possible to provide a product toner which does not impair the toner characteristics equivalent to those produced without using the fine powder toner. The reason why such an excellent effect is exhibited is considered as follows.

That is, the present inventors carefully analyzed the fine powder toner collected through the steps of mixing-kneading-cooling-pulverization-classification. The proportion of the mold release agent is relatively high, and if improper mixing setting conditions are taken in the mixing stage, not only the release agent increases in the fine powder toner generated thereafter, but also the proportion of the charge control agent increases. Therefore, the inventors have found that this is a factor that impairs the toner characteristics.

Here, the above-mentioned releasing agent such as wax depends largely on the particle size, but basically it is more easily melted by heat during kneading than other toner manufacturing materials, and if the particle size is extremely small, it is kneaded. When it is liquefied, this liquefied portion is easily separated from the binder resin when it is cooled and pulverized after kneading, and is easily pulverized. Further, it is considered that the charge control agent migrates into the liquefied release agent, and as a result, the charge control agent is also separated from the binder resin and migrates into the fine powder toner. Incidentally, it has been found that the proportion of the release agent in the fine powder toner to be reused in the present invention described later in the embodiment of the present invention is relatively high.

In this case, if the releasing agent such as wax is present in the final toner to some extent, the amount of the releasing agent does not cause a functional problem, but in the case of the charge control agent, the charging characteristics are greatly affected. Therefore, it is important to take measures to prevent transfer to fine powder toner during pulverization and classification. However,
In the conventional method, the fine powder toner to be reused is also mixed with the first mixing energy. Therefore, the fine powder toner containing a large amount of wax or the like is easily liquefied in the fine particle state due to the heat of the kneading step, and the charge control agent is contained in the fine powder toner. As a result, the amount of the charge control agent in the final toner became unstable (decreased).

On the other hand, in the present invention, since the fine powder toner to be reused is mixed with the first mixture at the second mixing energy lower than the first mixing energy, the conventional first mixing energy is mixed. Unlike that, fine powder toners are mixed and dispersed in a form of agglomeration to some extent, which suppresses melting and liquefaction due to heat during kneading, which in turn prevents unnecessary transfer of the charge control agent to the fine powder toner. It is thought that it is preventing.

In the toner manufacturing method of the present invention, a well-known mixing device such as a Henschel mixer, a ball mill and a dry blender is used in the mixing step. In the kneading step, a kneading device such as a uniaxial or biaxial continuous kneading machine or a Banbury mixer can be used. In addition, the crushing process, coarse crushing with a hammer mill or cutter mill,
For the fine pulverization with a jet mill or a 1-mill, and for the classification step, known devices such as a dispersion type classifier and a zigzag classifier are used.

In the toner manufacturing material of the present invention, the binder resin is not particularly limited as long as it is a commonly used resin, and specifically, polyester resin, styrene-acrylic resin, polyethylene resin, General resin materials such as polypropylene resin, polyamide resin, epoxy resin and polyurethane resin can be used.

As the colorant, carbon black,
Pigment Red 48: 1, Pigment Red 12
2, Pigment Red 57: 1, Pigment Yellow 97, Pigment Yellow 12, Pigment Yellow 17, Pigment Yellow 97, Pigment Green 7, Pigment Blue 15: 1, Pigment ・
Blue 15: 3 and the like can be mentioned. These colorants may be used alone or in combination of two or more.

As the above-mentioned charge control agent, for example, an oil-soluble dye such as a nigrosine dye, a fatty acid metal soap, a metal-containing monoazo dye, a metal complex or metal complex salt of salicylic acid or an alkylsalicylic acid, a boron-containing potassium salt compound, etc. may be used. You can

Further, as a release agent for adding an offset preventing effect, low molecular weight polypropylene, various waxes, silicone oils and the like are used.

To improve the fluidity of the toner material obtained by the method of the present invention, a fluidity improver such as hydrophobic silica fine particles or fluororesin particles is externally added and mixed to obtain a final product toner. Is preferred.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below with reference to embodiments of the present invention. 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, this color image forming apparatus (main body apparatus) 30 is provided with an opening / closing tray 31 on its rear surface (left side in the figure), and in the lower part from the front side (right side in the figure) of the main body apparatus. A removable paper cassette 32 is provided. A large number of sheets are placed and stored in the sheet cassette 32.

The main body device 30 has an upper lid 33 on its upper surface. Although not shown in the figure, a power switch, a liquid crystal display device, a plurality of input keys, and the like are arranged on the front side of the upper lid 33. The rear portion of the upper lid 33 is the main body device 3
A paper discharge tray 34 is formed together with the upper surface of the rear portion of 0.

Inside the main body device 30, a flat loop-shaped sheet conveying belt (hereinafter, simply referred to as a belt) 35 is arranged to extend in the front-rear direction at substantially the center, and both end portions in the horizontal direction of the loop are arranged. It is held by a driving roller 36 and a driven roller 37. The belt 35 is driven by the drive roller 36 and circularly moves in the counterclockwise direction indicated by the arrow R in the figure. Four photosensitive drums 38 (38a, 38b, 38c, 38d) are arranged along the upper circulation portion of the belt 35.
They are arranged side by side in multiple stages in the paper transport direction (from right to left in the figure).

These photosensitive drums 38 (38a, 38)
b, 38c, 38d) (hereinafter, only the peripheral devices around the photosensitive drum 38d are typically denoted by reference numerals), and the cleaner 41, the initialization charging roller 42, the writing head 43, and The developing device 44 (44d) is arranged. 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,
38c, developing devices 44a, 44b, 4
4c is arranged.

Developing device (developing hopper) 44 (44d)
Has a developing roller 45 rotatably supported in its lower opening. The developing roller 45 is in contact with the peripheral surface of the photosensitive drum 38 to form a developing section. The writing head 43 is disposed on the back surface of the upper lid 33 via a support member 46, and moves up and down in an arc along with the opening and closing of the upper lid 33, and descends when the upper lid 33 is closed to perform initialization charging. The recording portion is formed by being positioned between the roller 42 and the developing roller 45.

At the upstream end of the upper circulation portion of the belt 35,
The suction roller 47 moves the driven roller 37 via the belt 35.
Is pressed to form a sheet carrying-in section. The suction roller 47 presses the belt 35 while applying a suction bias to the sheet carried into the sheet carry-in section,
Electrostatically attract the paper to.

The photoconductor drum 3 at the most upstream side in the paper transport direction.
Each of the developing devices from the developing device 44a for 8a to the developing device 44d corresponding to the photosensitive drum 38d has three subtractive primary colors of M (magenta), C (cyan), Y (yellow), and Bk (black). Each color toner is stored. All of these toners are toners produced by the method of the present invention and having little environmental dependence based on the reuse of fine powder toners.

A pair of standby rolls 48 and a paper feed guide path 49 below the standby roll 48 are arranged on the upstream side of the belt 35 in the conveying direction (to the right in the figure). A roll pair 51 is arranged. The paper feed end of the above-described paper cassette 32 is located upstream (downward) of the feed roll pair 51. A paper feed roller 52 is arranged above the paper feed end of the paper cassette 32. The paper feed roller 52 is
The uppermost one sheet stored in the sheet cassette 32 is taken out and fed to the pair of feeding rolls 51.

On the other hand, a fixing device 53, a discharge roll pair 54, and a switching lever 55 are provided downstream of the belt 35 in the sheet conveying direction (on the left side in the drawing). The fixing device 53 includes a pressure contact roller, a fixing roller, a heat generating roller, a paper separating claw, a peripheral surface cleaning device, an oil applying member, which are assembled in a heat insulating casing.
It is composed of a thermistor or the like and heat-fixes the toner image transferred onto the paper on the paper.

When the switching lever 55 is in the lower position as shown in the figure, the switching lever 55 guides the paper to the paper discharge tray 34 via the upper discharge path 56 and the paper discharge roll pair 57. On the other hand, when the sheet is rotated upward, the sheet is guided to the open / close tray 31 opened on the rear surface of the main body device.

Between the belt 35 and the paper cassette 32,
An electric component section 58 to 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, and 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, creates print data, and transfers it to the engine unit.

The engine section includes a CPU, a ROM, etc.,
The input side receives data and command signals from the controller section, the output of the temperature sensor, the output of the paper detection sensor, etc., and the output side is 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 toner supply roller, a doctor blade, a developing unit scooping sheet, and the like, which will be described later, are connected to a bias power source driver that supplies a predetermined bias voltage. The engine unit drives and controls each unit based on data and command signals from the controller unit, the output of the temperature sensor, the output of the paper 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, number of sheets to be used, print mode, and other specifications are input by key input or as a signal from a connected host device, the feed roller 52 rotates once by a drive mechanism (not shown). Then, the sheets placed and accommodated in the sheet cassette 32 are fed to the standby roll pair 48 via the feeding roll pair 51. The pair of standby rolls 48 temporarily stops the rotation, and waits for the conveyance timing in a state where the leading end of the sheet is brought into contact with the nip portion formed by the pair of rollers.

Subsequently, the drive roller 36 rotates counterclockwise, and the driven roller 37 is driven to rotate counterclockwise as well. As a result, the belt 35 includes the photosensitive drums 38a, 38b, 38c, 38 having four upper circulation portions.
The whole body circulates counterclockwise by contacting d.

Along with this, the developing devices 44a, 44b, 4
4c, 44d and photosensitive drums 38a, 38b, 38
c and 38d are sequentially driven according to the print timing. The photosensitive drum 38 rotates in the clockwise direction, the initialization charging roller 42 imparts a uniform high negative charge to the peripheral surface of the photosensitive drum 38, and the writing head 42 moves to the peripheral surface of the photosensitive drum 38. 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 above 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 the low potential portion of the electrostatic latent image to form a toner image on the peripheral surface of the photosensitive drum 38 (reverse development).

At the timing when the leading edge of the toner image on the peripheral surface of the most upstream photosensitive drum 38a is rotatably conveyed to the facing point with the belt 35, the print start position of the paper coincides with the facing point. The pair of standby rolls 48 starts to rotate and feeds the paper to the paper carry-in section.

The driven roller 37 and the suction roller 47 nip and feed the fed sheet together with the belt 35. The sheet is attracted to the belt 35 and is conveyed to the first transfer portion formed by the photoconductor drum 38a and the transfer device.

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

The sheet 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 fixing, the sheet is discharged by the pair of discharge rollers 54 with the toner image on the openable tray 31 on the rear side or with the toner image on the discharge tray 34 on the upper side.

FIG. 2 is a side sectional view schematically showing a main part of the developing device 44. The developing device 44 shown in the figure is detachable from the color image forming apparatus 30 and is a developing unit that constitutes one image forming unit together with the drum unit. The developing device 44 includes an enclosure 61 that also serves as a toner hopper, and rotatably holds a developing roller 45 formed of a conductive rubber roller in a lower opening of the enclosure 61.
A toner 62 is accommodated inside the casing 61, and a toner stirring member 63 is provided so as to be embedded in the toner 62.

At the lowermost part of the developing device 44, a supply roller 64 made of a sponge body is arranged in pressure contact with the developing roller 45. The developing roller 45 is pressed against the peripheral surface of the upper right of the developing roller 45, and is made of a metal leaf spring-shaped doctor blade 65.
And a developing portion scooping sheet (conductivity regulating sheet) 66 is provided in contact with the lower peripheral surface. The developing section scooping sheet 66 is provided with a conductive regulating sheet biasing means, which will be described later, including a bias power source 71. Sealing members 67 are provided on both sides of the doctor blade 65 to prevent the toner 62 from leaking by isolating the inside and the outside of the housing 61 opening.

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

However, the triboelectric charge amount of the toner 62 has a close relationship with the adhesion and development (hereinafter referred to as photoconductor fog) on the non-image portion which occurs during development and causes a problem, and the toner having a small charge amount is The more easily photoconductor fogging occurs. Therefore, in order to prevent such photoconductor fogging, it is necessary to increase the triboelectric charge amount of the toner 62. When the triboelectric charge amount of the toner 62 is increased, the adhesive force to the developing roller 45 increases, so that the supply roller 6
It becomes necessary to give a strong rubbing force to No. 4.

Repeating the rotation for a long time with such a strong rubbing force causes deterioration of toner characteristics such as deterioration of charging ability and fluidity of the toner, which is not preferable. For example, when the charge amount decreases, the above-described photoconductor fogging occurs, and when the fluidity decreases, the lack of development in halftone dot printing occurs.

In the developing device 44 having such a problem, in one embodiment of the present invention, first, the developing roller 45 is composed of a core metal and a cylindrical semi-conductive (10 ⁶ Ωcm) surrounding the core metal. ), A developing bias of "-250 V" is applied to the core metal from the bias power source 68. Further, the supply roller 64 is composed of a cored bar and a cylindrical semi-conductive (10 ⁶ Ωcm) urethane sponge surrounding the cored bar, and a supply bias of “−500 V” is supplied from the bias power source 69 to the cored bar. Apply.

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

As described above, the developing portion scooping sheet 66 is made 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 roller 45. This is to reduce the charge of the toner 62 attached. As a result, the supply roller 6
Even with the weak rubbing force of 4, the developing roller 45 can be easily
The non-developed portion of the toner that has adhered and returned to the top can be scraped off.

In the developing device 44 shown in FIG.
For convenience, a developing bias voltage is applied to the developing roller 45 by a bias power supply 68, and a sheet bias voltage is applied to the developing unit scooping sheet 66.
Although the description has been given of the example in which the power supply is individually performed according to No. 1, it is not necessary to separately provide the power supplies. That is, in the actual developing unit configuration in the present invention, for example, a voltage dividing circuit including a resistance element is provided in the unit, and the bias voltage divided by the common bias power source of the apparatus main body is applied to each of the developing roller 45 and the developing unit scooping sheet 66. A voltage is applied.

By using the toner manufactured by the method of the present invention by the color image forming apparatus and the image forming process having the above-mentioned apparatus configurations, even in an environment of high temperature and high humidity,
It is possible to form an image with excellent image quality.

[0055]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing examples of producing a toner for developing an electrostatic image by the method of the present invention. First, an example of production of a conventional toner, which does not use a fine powder toner, for comparison in the present invention will be described.

[Production Example 1] [Black toner production material] Binder resin: polyester resin about 92% by mass Charge control agent: T-77 (manufactured by Hodogaya Chemical Co., Ltd.) about 1% by mass Colorant: carbon black (Monarch 880) about 4% by mass Release agent (wax): Polypropylene resin About 3% by mass The above toner production materials were mixed with a Henschel mixer FM20 manufactured by Mitsui Mining Co., Ltd. (peripheral speed of blades: 20 m / sec, stirring time: 4 minutes), and The kneading was carried out by a shaft continuous kneader. Then, after cooling and coarse crushing, crushing and classifying in the next step, average particle size 9 μm
To obtain a black toner material. At the same time, the average particle size is 5
A black fine powder toner having a particle size of not more than μm was obtained. Then, a black toner material having an average particle size of 9 μm and hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd.) were mixed in the Henschel mixer at a mass ratio of about 98: 2 to obtain a black toner of Production Example 1.

[Production Example 2] [Cyan toner production material] Binder resin: polyester resin 85.5% by mass Charge control agent: LR-147 (manufactured by Japan Carlit Co.) about 1% by mass Colorant 1: masterbatch pigment ( Polyester resin and Pigment Blue 15: 3 kneaded at a ratio of 7: 3 10% by mass Colorant 2: Masterbatch pigment (Polyester resin and Pigment Green 7 kneaded at a ratio of 7: 3) 0.5% by mass Release agent (wax): Polypropylene resin About 3% by mass The above toner production material was subjected to the same steps as in Production Example 1 to obtain a cyan toner material having an average particle diameter of 9 μm. At the same time, a cyan fine powder toner having an average particle diameter of 5 μm or less was obtained. And
A cyan toner of Production Example 2 was obtained by mixing the cyan toner material having an average particle diameter of 9 μm and the hydrophobic silica in a mass ratio of about 98: 2 in the Henschel mixer.

[Production Example 3] [Material for producing yellow toner] Binder resin: Polyester resin 86% by mass Charge control agent: LR-147 (manufactured by Japan Carlit Co., Ltd.) about 1% by mass Colorant: Masterbatch pigment (with polyester resin) Pigment Yellow 17 is kneaded and produced at a ratio of 7: 3) 10% by mass Release agent (wax): Polypropylene resin About 3% by mass An average particle size of the above toner production material through the same steps as in Production Example 1. A 9 μm yellow toner material was obtained. At the same time,
A yellow fine powder toner having an average particle diameter of 5 μm or less was obtained. Then, a yellow toner material having an average particle diameter of 9 μm and the hydrophobic silica were mixed in the Henschel mixer at a mass ratio of about 98: 2 to obtain a yellow toner of Production Example 3.

[Production Example 4] [Magenta toner production material] Binder resin: polyester resin 86% by mass Charge control agent: LR-147 (manufactured by Japan Carlit Co.) about 1% by mass Colorant: masterbatch pigment (with polyester resin) Pigment Red 57: 1 kneaded and produced in a ratio of 7: 3) 10% by mass Release agent (wax): polypropylene resin About 3% by mass An average of the above toner production materials through the same steps as in Production Example 1 A magenta toner material having a particle size of 9 μm was obtained. At the same time,
A magenta fine powder toner having an average particle diameter of 5 μm or less was obtained. Then, the magenta toner material having an average particle size of 9 μm and the hydrophobic silica were mixed in the Henschel mixer at a mass ratio of about 98: 2 to obtain a magenta toner of Production Example 3.

Comparative Example 1 20 parts by mass of the black fine powder toner having an average particle diameter of 5 μm or less obtained in Manufacturing Example 1 was added to 100 parts by mass of the black toner manufacturing material of Manufacturing Example 1 to prepare Manufacturing Example 1. Mixing under the same mixing conditions (blade peripheral speed 20
m / sec, stirring time 4 minutes), and kneading was carried out by a biaxial continuous kneader. Then, after cooling and coarse pulverization, pulverization and classification were carried out in the next step to obtain a black toner material having an average particle diameter of 9 μm. Comparative Example 1 was prepared by mixing the black toner material and the hydrophobic silica in the Henschel mixer in a mass ratio of about 98: 2.
Of black toner was obtained.

Comparative Example 2 20 parts by mass of the cyan fine powder toner having an average particle diameter of 5 μm or less obtained in Manufacturing Example 1 was added to 100 parts by mass of the cyan toner manufacturing material of Manufacturing Example 2.
Mixing under the same mixing conditions as in Production Example 2 (peripheral speed of the blade is 20 m / s
ec, stirring time 4 minutes), and kneading was carried out by a biaxial continuous kneader. Then, after cooling and coarse crushing, crushing and classifying in the next step,
A cyan toner material having an average particle size of 9 μm was obtained. The cyan toner material and the hydrophobic silica were mixed in the Henschel mixer at a mass ratio of about 98: 2 to obtain a cyan toner of Comparative Example 2.

Comparative Example 3 To 100 parts by mass of the yellow toner manufacturing material of Manufacturing Example 3, 20 parts by mass of the yellow fine powder toner having an average particle diameter of 5 μm or less obtained in Manufacturing Example 3 was added, and manufacturing example 3 was obtained. Mixing under the same mixing conditions (blade peripheral speed 20
m / sec, stirring time 4 minutes), and kneading was carried out by a biaxial continuous kneader. Then, after cooling and coarse pulverization, pulverization and classification were carried out in the next step to obtain a yellow toner material having an average particle diameter of 9 μm. The yellow toner material and the hydrophobic silica were mixed in the Henschel mixer in a mass ratio of about 98: 2, and Comparative Example 3
Yellow toner was obtained.

Comparative Example 4 20 parts by mass of magenta fine powder toner having an average particle size of 5 μm or less obtained in Manufacturing Example 4 was added to 100 parts by mass of the magenta toner manufacturing material of Manufacturing Example 4 to prepare Manufacturing Example 4. Mixing under the same mixing conditions (blade peripheral speed 20
m / sec, stirring time 4 minutes), and kneading was carried out by a biaxial continuous kneader. Then, after cooling and coarse crushing, the powder was crushed and classified in the next step to obtain a magenta toner material having an average particle diameter of 9 μm. This magenta toner material and the above hydrophobic silica were mixed in the above Henschel mixer in a mass ratio of about 98: 2, and Comparative Example 4
To obtain a magenta toner.

Example 1 The black toner production material of Production Example 1 was mixed under the same mixing conditions as in Production Example 1 (circumferential speed of the blade was 20 m / sec, stirring time was 4 minutes), and the mixture 100 was mixed.
Average particle diameter of 5 μm obtained in Production Example 1 with respect to parts by mass
20 parts by mass of the following black fine powder toner was added, and mixed again with the Henschel mixer under different mixing conditions (peripheral speed of the blade was 10 m / sec, stirring time was 4 minutes), and kneaded with a biaxial continuous kneader. Then, after cooling and coarse pulverization, pulverization and classification were carried out in the next step to obtain a black toner material having an average particle diameter of 9 μm.
The black toner material and the hydrophobic silica are about 98:
The Henschel mixer was mixed in a mass ratio of 2 to obtain a black toner of Example 1.

Example 2 The cyan toner production material of Production Example 2 was mixed under the same mixing conditions as in Production Example 2 (blade peripheral speed 2
(0 m / sec, stirring time: 4 minutes), then, to 100 parts by mass of this mixture, 20 parts by mass of the cyan fine powder toner having an average particle size of 5 μm or less obtained in Production Example 2 was added, and the mixture was again mixed with the Henschel mixer. Mix under different mixing conditions (blade peripheral speed 1
0 m / sec, stirring time 4 minutes), and kneading was carried out by a biaxial continuous kneader. Then, after cooling and coarse pulverization, pulverization and classification were carried out in the next step to obtain a cyan toner material having an average particle diameter of 9 μm. This cyan toner material and the hydrophobic silica were mixed in the Henschel mixer at a mass ratio of about 98: 2 to obtain a cyan toner of Example 2.

Example 3 The yellow toner production material of Production Example 3 was mixed under the same mixing conditions as in Production Example 3 (peripheral speed of the blade was 20 m / sec, stirring time was 4 minutes), and the mixture 100 was mixed.
Average particle diameter of 5 μm obtained in Production Example 3 with respect to parts by mass
20 parts by mass of the following yellow fine powder toner was added, and the mixture was mixed again with the above Henschel mixer under different mixing conditions (peripheral speed of the blade was 10 m / sec, stirring time was 4 minutes), and kneaded with a biaxial continuous kneader. Then, after cooling and coarse pulverization, pulverization and classification were carried out in the next step to obtain a yellow toner material having an average particle diameter of 9 μm.
Approximately 98:
The above Henschel mixer was mixed in a mass ratio of 2 to obtain a yellow toner of Example 3.

Example 4 The material for producing magenta toner of Production Example 4 was mixed under the same mixing conditions as in Production Example 4 (circumferential speed of the blade was 20 m / sec, stirring time was 4 minutes), and the mixture 100 was mixed.
Average particle diameter of 5 μm obtained in Production Example 4 with respect to parts by mass
The following 20 parts by mass of magenta fine powder toner was added, mixed again with the Henschel mixer under different mixing conditions (blade peripheral speed: 10 m / sec, stirring time: 4 minutes), and kneaded by a biaxial continuous kneader. Then, after cooling and coarse crushing, the powder was crushed and classified in the next step to obtain a magenta toner material having an average particle diameter of 9 μm.
About 98: the magenta toner material and the hydrophobic silica.
The Henschel mixer was mixed in a mass ratio of 2 to obtain a magenta toner of Example 4.

Next, the toner samples obtained as described above are quantitatively filled into dedicated toner cartridges, and then the color printer shown in FIG. 1 (printer manufactured by Casio Computer Co., Ltd .: Color Page Presto N-612II) is used. After setting, printing was performed until the toner was used up in a printing pattern with a pixel ratio of 5%, and the total number of printed sheets, white paper fog, photoconductor fog, etc. were evaluated.

Among them, the evaluation of white paper fog and photoconductor fog was carried out by a manufacturing method which does not use fine toner (manufacturing example 1 (black toner) which is a toner having a characteristic conventionally accepted as a product toner). Example 2 (cyan toner),
The printing results of Production Example 3 (yellow toner) and Production Example 4 (magenta toner) are used as the determination criteria. When the results are the same as those of the determination criteria toner, “◯” is given, and when the results are inferior. It was evaluated as "x". Regarding the number of printed sheets, the actual number is printed as "O" when the number exceeds 6500 which is the standard number of cartridges for the Casio Computer Printer, and as "X" when the number does not exceed the standard number. A table summarizing the results is shown below.

[0070]

[Table 1]

From Table 1, in the toner manufacturing material mixing method when reusing the fine powder toner as the toner manufacturing material,
The fine powder toner is simultaneously charged into the Henschel mixer together with the binder resin, the colorant, the charge control agent, and the release agent, and the same predetermined condition as when the fine powder toner is not used (first mixing energy)
The toner manufactured by the method of mixing the materials in Comparative Example 1 (Comparative Example 1
4 to 4) were inferior in toner properties such as white paper fog, photoconductor fog, and the number of printable prints as compared with the toners manufactured without using the fine powder toner (Production Examples 1 to 4), First, the binder resin, the colorant, the charge control agent, and the release agent are charged into the Henschel mixer, the materials are mixed under the same predetermined conditions (first mixing energy) as when the fine powder toner is not used, and then the fine powder toner is used. The toner (Examples 1 to 4) manufactured by the method of the present invention, which is additionally charged into a mixer and further mixed under appropriate mixing conditions (second mixing energy lower than the first mixing energy), is a fine powder. Toners produced without using toner (Production Examples 1 to
It can be seen that it has the same performance as 4) in white paper fogging, photoconductor fogging, and the number of printable sheets.

In the above embodiment, as a mixing condition of each toner manufacturing raw material when the fine powder toner is not used, the peripheral speed of the blade of the Henschel mixer is 20 m / sec and the stirring is performed as shown in Manufacturing Examples 1 to 4. Although the time was set to 4 minutes and this was explained as a prerequisite for the judgment reference toner, this condition is a condition set experimentally in order to sufficiently mix the toner manufacturing materials and to apply it to the Casio computer printer. However, the conditions are not necessarily limited to the above. By the way, the peripheral speed of the blade is 20 m / sec and the stirring time is 1
As a result of conducting a reference comparison experiment for about a minute, the toner produced by this has no problem as a product toner.

However, when the fine powder toner is used under such conditions (the peripheral speed of the blade is 20 m / sec and the stirring time is about 1 minute), there is no special device like the method of the present invention. It has been additionally tested that a problem occurs in the characteristics of the obtained toner. That is, the fine powder toner is simultaneously charged into a Henschel mixer together with a binder resin, a colorant, a charge control agent and a release agent, and the material is used under the above conditions (peripheral speed of the blade is 20 m / sec, stirring time is about 1 minute). The toners manufactured in the step of mixing are the same as those in Comparative Examples 1 to 4 above.
As with the above, unfavorable results are obtained.

On the other hand, when the mixing method (two-step mixing method) of the present invention as described in Examples 1 to 4 is adopted, the same result as that of the toner produced without using the fine powder toner is obtained. Has been. Further, as a condition for mixing after adding the fine powder toner (second mixing step), the peripheral speed of the blade is 1
It was explained that 0 m / sec and the stirring time was 4 minutes, but this is also 1
There is no problem in shortening it to about a minute. The bottom line is
It is to disperse the finely divided toner in the toner manufacturing material appropriately without giving excessive mixing energy.

[0075]

As described above in detail, according to the present invention, the fine powder toner can be used as a toner manufacturing material by slightly changing the setting of the manufacturing process conditions without requiring any special equipment or equipment. It is possible to produce a product toner that can be reused for a long time and has excellent toner characteristics. Therefore, the yield of toner is improved, and inexpensive toner can be easily provided.

[Brief description of drawings]

FIG. 1 is a diagram schematically illustrating an internal configuration of a color image forming apparatus according to an embodiment of the 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]

30 ... Color image forming apparatus 31 ... Openable tray 32 ... Paper cassette 33 ... Top cover 34 ... Paper ejection tray 35 ... Paper transport belt 36 ... Drive roller 37 ... Driven roller 38, 38a, 38b, 38c, 38d ... Photosensitive drum 39 ... Sheet transfer device 41 ... Cleaner 42 ... Initializing charging roller 43 ... Writing head 44a, 44b, 44c, 44d ... Developing devices.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Goshi Mitsui             4084 Miyadera, Iruma City, Saitama Prefecture Casio Electronics             Business (72) Inventor Yasuo Kamoshita             4084 Miyadera, Iruma City, Saitama Prefecture Casio Electronics             Business F-term (reference) 2H005 AB04 EA07

Claims (2)

[Claims] 1. A mixing step of mixing at least a binder resin, a colorant, a charge control agent and a release agent, and a mixture obtained by the mixing step of kneading, cooling, pulverizing and classifying in order. A toner is manufactured by mixing the toner material having a predetermined particle diameter obtained by the classification step with an external additive as required, while fine particles classified as particles having a smaller particle diameter than the toner material. A method for producing a toner for electrostatic image development by recycling fine toner by recovering the toner and returning the fine powder toner to the mixing step, wherein the mixing step comprises at least the binder resin, A first mixing step of mixing a colorant, a charge control agent, and a release agent with a first mixing energy; and a first mixing step obtained by the first mixing step.
A second mixing step of adding the recovered fine powder toner to the mixture and mixing with a second mixing energy lower than the first mixing energy, and containing the fine powder toner obtained after the second mixing step. The method for producing a toner for electrostatic image development, characterized in that the toner containing fine powder toner is produced on the basis of the second mixture of the second mixture. 2. The method for producing an electrostatic image developing toner according to claim 1, wherein 5 to 30 parts by mass of the recovered fine powder toner is added to 100 parts by mass of the first mixture.