JP3511066B2 - Kneading machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a kneading machine, and more particularly to a kneading machine suitable for producing a toner for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like.

[0002]

2. Description of the Related Art A method of developing an electrostatic charge image is roughly classified into a liquid development method using a developer in which various pigments and dyes are finely dispersed in an insulating organic liquid, and a polar method for a natural resin or a synthetic resin. There are dry development methods such as a cascade method using a fine powder developer called a toner in which a control agent and a colorant are dispersedly contained, a magnetic brush method, a powder cloud method, and the like.

In the dry developing method, the electrostatic charge image is developed using toner, transferred onto a transfer sheet, and then fused on the transfer sheet for development. At that time, the fusion of the toner image is performed by contact with the solution vapor, pressurization or heating.

However, when developing an electrostatic charge image, a phenomenon in which toner is developed even in a non-image portion, so-called background stain may occur. Further, a phenomenon in which toner is difficult to be developed in the image area, that is, a so-called image density decrease may occur. Further, when a large number of copies are made by a copying machine, a phenomenon in which the image density is reduced and scumming occurs, that is, the durability is reduced due to filming, earlier than the life of the developer.

These are all caused by the poor dispersibility of the colorant, the polarity control agent and the releasing resin in the toner. If the dispersibility of the colorant, the polarity control agent, and the release resin is poor, the toner has a low charging ability or a large variation in the charging ability, resulting in a low image density. Further, the toner is developed in the non-image area due to the deterioration of the charging ability, and the background stain occurs. Further, when the release resin is not well dispersed, the release resin is released on the toner surface and filmed on the carrier surface, so that the durability is lowered.

Conventionally, in order to manufacture a toner with low background stain, high density, and long life, a manufacturing technique for increasing the dispersibility of the colorant, the polarity control agent, and the releasing resin in the toner has been adopted.
One of them is to knead toner raw materials with a kneader. In this kneading, the smaller the kneading amount per unit time, the better the kneading dispersion, and the toner with low background stain, high density and long life can be obtained. It is considered that this is because the smaller the kneading amount per hour, the longer the residence time in the kneader and the longer the dispersion time.

As another technique, first, a part of the binder resin and a part or all of the colorant and the polarity control agent are kneaded, cooled and pulverized, and the kneaded product is kneaded again with the remaining binder resin. There is a so-called masterbatch method.

Other techniques include changing the shape of the rotary screw in the kneading machine to increase the dispersing power of the kneaded product (JP-A-2-34307), providing a gate in the kneading chamber, There is a device in which the opening is adjusted (Japanese Patent Publication No. 4-22607).

[0009]

However, each of the above conventional techniques has the following problems. That is, when the dispersion is promoted by adjusting the kneading amount per unit time, the dispersion of the material proceeds, but the production efficiency is poor. The masterbatch method has good dispersibility, but the kneading step
It is necessary to repeat the process, which is also inefficient in production. Further, since changing the screw shape is intended for a specific kneader, the materials cannot be kneaded by another kneader.

In a kneading machine having a gate in the kneading chamber, it is considered that the narrower the gate is, the more the material is dispersed. However, the compatibility of the material to be kneaded depends on the installation location of the gate and the opening of the gate. Since the dispersibility effect changes, it is very difficult to properly adjust the gate position and gate opening.

The present invention has been made in view of the above points, and an object thereof is to provide a kneading machine capable of increasing the kneading amount per unit time, especially for developing a high-quality electrostatic latent image. It is to provide a kneader that can obtain a toner.

The kneading machine according to claim 1 is a kneading machine having a gate in a kneading chamber capable of adjusting the opening degree of a material to be kneaded, wherein the gates are provided at two or more places, and a supply port for the material to be kneaded is provided. When the length of the kneading section from the outlet to the outlet is L,
The gate closest to the supply port is 0.1
The gate closest to the discharge port is provided at a position of L to 0.5L, and the gate inner diameter on the discharge port side is set to be closer to the discharge port from the supply port. When the inner diameter of the gate closest to the supply port is Da and the inner diameter of the gate closest to the discharge port is Db, the inner diameter of the gate is smaller than the inner diameter of the gate, The inner diameter ratio Da / Db is more than 1.0 and 1.15 or less.

A kneading machine according to a second aspect is a kneading machine having a gate in a kneading chamber capable of adjusting an opening degree of a kneading material passage, wherein the gates are provided in two or more places, and a kneading material supply port is provided. When the length of the kneading section from the outlet to the outlet is L,
The gate closest to the supply port is 0.1
The gate closest to the discharge port is provided at a position of L to 0.5L, and the gate inner diameter on the discharge port side is set to be closer to the discharge port from the supply port. Or smaller than the inner diameter of the gate on the supply port side, and the clearance area between the barrel and the screw shaft is Oa, and the clearance area between the gate and the screw shaft closest to the discharge port is Ob
Then, the ratio Oa / Ob is set to 2 to 15.

[0014]

The kneading machine of the present invention is the kneading machine of claim 1, wherein the kneading set temperature from the supply port to the discharge port is such that the temperature on the discharge port side is lower than the temperature on the supply port side, Alternatively, the temperature may be equal to the temperature on the supply port side.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the structure of the present invention will be described in detail with reference to the embodiments shown in the drawings, and the operation and effect of this structure will be described. Example 1 FIG. 1 is a vertical cross-sectional view showing a main part of a kneading machine, and FIG. 2 is A of FIG.
3 is a sectional view taken along line A-A, FIG. 3 is a sectional view taken along line B-B in FIG. 1, and FIG. 4 is an explanatory sectional view of the kneading action. In these figures, 1 is a feed zone for the material to be kneaded,
2 to 8 are kneading parts, 9 is a kneaded material discharge port, 10 is a screw shaft, 11 is a hopper, 12 is a barrel, 13 is a heater, 14 is a gate, and 15 is a screw part.

This kneader comprises a barrel 1 of kneading sections 2-8.
When two gates 14 are provided in the two parts, and the length of the kneading portion from the supply port for the material to be kneaded to the discharge port 9 for the kneaded material is L, the position of the gate 14a closest to the supply port is
The supply port (this corresponds to 0.0L, see FIG. 1)
To 0.1L to 0.5L, and the position of the gate 14b closest to the discharge port 9 is 0.5L from the supply port.
Within 0.9 L, the inner diameter of the gate 14 on the discharge port 9 side is smaller than or equal to the inner diameter of the gate 14 on the supply port side (see FIG. 3). Is characterized by.

Embodiment 2 In the embodiment shown in FIG. 1, two gates 14 are provided, whereas in the embodiment shown in FIG. 5, the gates 14 are provided at six places. It is the same.

In the embodiment shown in FIGS. 1 and 5, the provision of the gate 14 makes it difficult for the material to be kneaded to pass through the gate as shown in FIG. 4 and the material passing through the gate to be divided. And the effect of replacing the material by mixing with the material before and after is obtained. In this way, the material is compressed / replaced by the gate when passing through the gate, so the compression / dispersion effect is higher when two or more gates are provided than when one gate is provided.

When the length of the kneading section from the supply port of the material to be kneaded to the discharge port 9 is L, the range of 0.0L (corresponding to the supply port) to 0.1L from the supply port is 0 in the material transport section. .1L
The range of 0.5 L to 0.5 L is a material melting part, the range of 0.5 L to 0.9 L is a kneading part, and the range of 0.9 L to 1.0 L is a kneading material transporting part, which can be classified by function.

When the position of the gate closest to the supply port is 0.1 L to 0.5 L from the supply port, the compatibility / substitution in the material melting portion is promoted. Further, when the position of the gate closest to the discharge port 9 side is 0.5 L to 0.9 L, compression / shearing in the kneading section is promoted and dispersion is promoted.

However, if the position of the gate closest to the supply port is 0.0L or more forward of 0.1L or rearward of 0.5L from the supply port, the compatibility in the material melting portion The substitution effect is low, and the dispersion effect in the kneading section becomes poor. Further, if the position of the gate closest to the discharge port 9 is before 0.5L or behind 0.9L from the supply port, the compression / shearing effect in the kneading section becomes low and the dispersion effect becomes poor.

Regarding the gate inner diameter, if the gate inner diameter on the discharge port 9 side is narrower than the gate inner diameter on the supply port side or is equal to the gate inner diameter on the supply port side, the material filling rate in the kneading machine becomes high. Since it is the highest in front of the gate, the compression / shearing efficiency in the kneading section is increased and the dispersion is improved.

However, if the inner diameter of the gate on the discharge port 9 side is larger than the inner diameter of the gate on the supply port side, the material filling rate in the material melting section becomes high, and conversely the filling rate in the kneading section becomes low.
The compression / shearing efficiency in the kneading section becomes low, and the dispersibility of the material is better than when the inner diameter of the gate on the discharge port 9 side is narrower than the inner diameter of the gate on the supply port side or equal to the gate inner diameter on the supply port side. Becomes worse.

Therefore, the dispersion can be improved by making the inner diameter of the gate on the side of the discharge port 9 smaller than the inner diameter of the gate on the side of the supply port or set to be equal to the inner diameter of the gate on the side of the supply port.
Productivity can be increased.

The inner diameter of the gate closest to the supply port is D
a, when the gate inner diameter closest to the discharge port 9 is Db,
When the ratio Da / Db is more than 1.0 and 1.15 or less, the compatibilization / substitution in the material melting portion and the compression / shearing effect in the kneading portion are enhanced, and the dispersion proceeds.

Further, the area of the gap 16 between the barrel 12 and the screw shaft 10 is Oa (see FIG. 2),
When the area of the gap 17 between the gate 14b closest to the discharge port 9 and the screw shaft 10 is Ob (see FIG. 3), if the ratio Oa / Ob is within the range of 2 to 15, the material Dispersion progresses.

The gap area is calculated as follows.
That is, the vacant area of the gate having the inner diameter Db = π × (Db / 2) ² , the cross-sectional area of the screw shaft 10 having the diameter S = π × (S /
2) ² , the internal cross-sectional area of the barrel 12 having the inner diameter R = π × (R / 2) ² , and the gap area Oa = π × [(R / 2) ² − (S /
2) ² ], the gap area Ob = π × [(Db / 2) ² − (S / 2)
² ], Oa / Ob = [(R / 2) ² − (S / 2) ² ] / [(D
b / 2) ² − (S / 2) ² ].

The ratio Oa / Ob of the gap area is 2
If it is smaller, the material compression becomes smaller when the material passes through the gate 14, and if the ratio is larger than 15, the material compression becomes too large when the material passes through the gate 14 to the motor of the kneader. Therefore, the kneading processing amount cannot be increased because the load of is too large.

Further, regarding the kneading set temperature from the material input port to the discharge port 9, the temperature at the discharge port 9 side is made lower than that at the supply port side, or made equal to that at the supply port side, so that the material in the kneading section is made. Since the viscosity becomes high, dispersion proceeds.

The kneader of the present invention includes various continuous kneaders having a rotary shaft, and specific examples thereof include a single-screw extruder and a twin-screw extruder.
Further, the kneading machine of the present invention is for kneading an electrostatic image developing toner (electrostatic latent image developing toner) using a composition containing a binder resin, a releasing resin, a polarity control agent and a colorant as a raw material. Can be very effectively applied to. This toner is manufactured by kneading the raw materials with a kneader, then pulverizing and classifying.

When the above raw materials are kneaded by the kneader shown in FIG. 1 and then the toner is manufactured through the above steps, the raw materials fed from the hopper 11 are fed from the feeding zone 1 to the kneading sections 2 to 2.
It is discharged from the kneaded material discharge port 9 through Kneading section 2
The kneading temperature of ~ 8 is set by a known method such as heating with a heater 13 provided outside the barrel 12 or passing a pipe inside the barrel 12 and flowing oil or cooling water through the pipe to heat or cool. It

However, the kneaded materials in the kneading sections 2 to 8 are not necessarily equal to the kneading set temperature. In both the high-temperature zone and the low-temperature zone, the measured temperature is equal to or higher than the set temperature because the material is sheared, that is, the heat is generated due to the cutting of molecules. Further, since the temperature of the kneading machine is controlled by the barrel 12, since the kneading material transport speed is faster than the heat transfer speed to the inside of the kneading machine in the low temperature zone, heat is generated by shearing even when the kneading material transport speed is slow. Therefore, the actually measured temperature is equal to or higher than the set temperature. Therefore, if the set temperature is constant, the actual kneading temperature is determined by the kneading amount per unit time and the screw rotation speed.

When the toner is produced by the kneading machine of the present invention, as the binder resin and the releasing resin, all known resins can be used.

For example, polystyrene, poly (p-styrene), homopolymers of styrene such as polyvinyltoluene or a substitution product thereof, styrene-p-chlorostyrene copolymer,
Styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-methyl acrylate copolymer,
Styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene- α-chloromethacrylic acid methyl copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, Styrene-maleic acid copolymer, styrene-based copolymers such as styrene-maleic acid ester copolymer, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane,
Epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or aliphatic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc., either alone or mixed. Can be used.

As the colorant, all known colorants for toner can be used. Examples of black colorants include carbon black, aniline black, furnace black and lamp black.

As the cyan colorant, for example, phthalocyanine blue, methylene blue, Victoria blue, methyl violet, aniline blue, ultramarine blue and the like can be used.

As the magenta colorant, for example, Rhodamine 6G lake, dimethylquinacridone, Watching Red, Rose Bengal, Rhodamine B, alizarin lake, etc. can be used.

As the yellow colorant, for example, chrome yellow, benzidine yellow, Hansa yellow, naphthol yellow, molybdenum orange, quinoline yellow, tartrazine and the like can be used.

Further, these toners may contain, for example, a dye / pigment, a charge control agent, etc. in order to more efficiently impart the charge. Examples of the polarity control agent include metal complex salts of monoazo dyes, nitrohumic acid and its salts, metal complexes of salicylic acid, naphthoic acid, dicarboxylic acids such as Co, Cr and Fe, organic dyes, and quaternary ammonium salts.

As a method for producing the toner after kneading the raw materials, a conventionally known method can be adopted. After kneading the raw materials, for example, they are solidified by cooling, pulverized by a jet mill and classified to obtain a toner.

When the toner is produced by the kneading machine of the present invention, an additive for a toner which is generally widely used, for example, a fluidizing agent such as colloidal silica, is used, if necessary.
A metal oxide such as titanium oxide or aluminum oxide, an abrasive such as silicon carbide, a lubricant such as a fatty acid metal salt, or the like may be contained. To mix these additives with the toner, a conventionally known method may be used, and the additives may be mixed with a device such as a Henschel mixer or a speed kneader.

The toner produced by the kneading machine of the present invention can be used as a dry one-component developer and a dry two-component developer. When used as a dry two-component developer, the use amount of curia and toner is 30 to 90% of the surface area of the toner particles when the toner particles adhere to the surface of the carrier particles.
It is preferable to mix both particles to the extent that they occupy%. As the carrier, conventionally known carriers can be used, and examples thereof include non-coated carriers such as iron powder and ferrite, carriers coated with styrene-acrylic resin, silicon resin, fluorine-modified acrylic resin, and granulation carriers.

A test example of toner production carried out by using the kneading machine of the present invention will be given below. However, the kneading machine of the present invention is not limited to the production of toner but can be widely applied to kneading powders and the like. is there.

Test Examples 1 to 14 [Production of toner] Styrene-acrylic copolymer 95 parts by weight Polypropylene 5 parts by weight Carbon black 10 parts by weight Zinc salicylate 2 parts by weight Mixture of the above composition having a screw shaft diameter of 32 m.
m, using a uniaxial kneader having an inner diameter of 46 mm, the melt kneading, cooling under the conditions shown in [Table 1] to [Table 4],
The toner was pulverized and classified to obtain a toner having an average particle size of 11.6 μm.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

[Table 4]

Explaining the * marks in [Table 1] to [Table 4], the "kneading temperature" is the "kneading set temperature",
In this "kneading temperature" column, for example, "2-4" indicates the kneading parts 2-4 (see FIG. 1). Further, for example, “0.20” in the “gate position” column indicates that the gate is provided at a position at a distance of 0.2 L from the supply port.

[Evaluation Method] 5 parts by weight of toner and 95 parts by weight of non-coated amorphous iron powder carrier were continuously stirred in a ball mill to prepare a developer, and IMAGIO-3 manufactured by Ricoh Co., Ltd.
It was set in a modified 20 digital copying machine, and the durability of 30,000 sheets was evaluated with respect to image density, background stain, and charge amount. The image density was measured using a Macbeth densitometer, the background stain was measured using a step sample, and the charge amount was measured using a blower. The results are shown in [Table 5] and [Table 6].

[0052]

[Table 5]

[0053]

[Table 6]

[Results] As in Test Examples 1 to 4, there were two or more gates in the barrel of the kneading section between the raw material supply zone and the kneading material discharge port, and the kneading section length L from the supply port to the discharge port was set. On the other hand, the gate closest to the supply port is at a position of 0.1L to 0.5L from the supply port, and the gate closest to the discharge port is 0.5L from the supply port.
L-0.9L, and the inner diameter of each gate is smaller than the discharge port side than the supply port side, or equivalent to the supply port side, and gates like Test Examples 9-14. Even if there is one or two or more gates, the position of the gate closest to the supply port is 0.1L to 0.5L from the supply port.
Not within the range, the position of the gate closest to the outlet is not within the range of 0.5L to 0.9L from the inlet, or the gate inside diameter on the outlet side is larger than the inside gate diameter on the inlet side Comparing with the former (), the latter ()
It can be seen that the image density, the background stain, and the change in the charge amount show good results, and the kneading amount can be increased. Also,
As in Test Example 5, the gate inner diameter ratio Da / Db is 1.0.
Those larger than 1.15 and below are in Test Example 1
4 to 4, the image density, the background stain, and the change in the charge amount are all better. Further, as in Test Example 6, the ratio Oa / Ob of the clearance area Oa between the barrel and the screw shaft and the clearance area Ob between the gate and the screw shaft closest to the outlet is within the range of 2 to 15. In the case of (1), the image density, background stain, and change in charge amount all show good results. Further, regarding the kneading set temperature from the charging port to the discharging port, as in Test Examples 7 and 8, the temperature of the discharging side zone is set lower than the temperature of the feeding side zone, or the temperature of the feeding side zone is set. Image density,
Both the background stain and the change in the charge amount show good results, and it can be seen that the kneading amount can be increased.

[0055]

As is apparent from the above description, claim 1
According to the kneader described in (1), the gate has a high effect of displacing and compressing the material to be kneaded, and compatibilization and substitution in the material melting portion and compression and shearing in the kneading portion are promoted respectively, so that the material is dispersed As a result, the material to be kneaded can be efficiently kneaded, and therefore the kneading amount per time can be increased. Therefore, by kneading the toner raw material with the kneading machine of claim 1, a toner having a good raw material dispersibility can be produced, so that the charging ability of the toner is improved and filming on the carrier surface occurs. There is an effect that high quality toner can be obtained without any problems such as image density reduction, background stain, and poor durability. In the kneading machine according to claim 2, the ratio Da / Db between the inner diameter Da of the gate and the inner diameter Db of the gate closest to the kneaded material discharge port is set to be larger than 1.0 and not larger than 1.15. Since the dispersing action of the material to be kneaded is further improved as compared with the case of claim 1, the kneading amount per unit time can be further increased, and a higher quality toner can be produced,
Since the charging ability of the toner is improved and filming on the surface of the carrier does not occur, a toner free from problems such as reduction in image density, background stain, and poor durability can be obtained. In the kneading machine according to claim 3, a clearance area Oa between the barrel and the screw shaft and a gate closest to the kneaded material discharge port are provided.
Ratio Oa / Ob of clearance area Ob between screw shafts
By setting 2 to 15, the material to be kneaded for the barrel volume is compressed by the gate, so that the dispersing action of the material to be kneaded is further improved as compared with the case of claim 1, and the kneading amount per hour is increased. In addition to further increase, there is an effect that a higher quality toner can be manufactured. In the kneading machine according to claim 4, by setting the kneading set temperature at the kneaded material discharge port side to be equal to or lower than the kneading set temperature at the raw material supply port side, the kneading progresses to a certain degree, and then the raw material viscosity is further reduced to disperse the kneaded product. Since the property is enhanced, an extremely excellent kneading action can be obtained as in the second and third aspects, the kneading amount can be increased, and a higher quality toner can be produced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a main part of a kneading machine according to an embodiment of the present invention.

FIG. 2 is a cut end view taken along line AA of FIG.

FIG. 3 is a sectional end view taken along the line BB of FIG.

FIG. 4 is an explanatory sectional view of a kneading action.

FIG. 5 is a vertical sectional view showing a main part of a kneading machine according to another embodiment.

[Explanation of symbols]

1 Kneading material supply zone 2-8 kneading section 9 Kneaded material discharge port 10 screw shaft 11 hopper 12 barrels 13 heater 14,14a, 14b 15 screw 16,17 gap

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-4-28505 (JP, A) JP-A-54-100566 (JP, A) JP-A-59-214631 (JP, A) Actual development Sho-57- 90733 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B29B ^7/ 00-7/94 B01F ^7/ 00-7/32

Claims (2)

(57) [Claims] 1. A kneading machine having a gate capable of adjusting the opening degree of a material passage to be kneaded in the kneading chamber, wherein the gates are provided at two or more locations, and a screw in the kneading chamber on the side of the material to be kneaded is supplied.
When the length of the kneading section from the end of the Leu shaft to the tip thereof is L, the gate closest to the supply port is provided at a position of 0.1 L to 0.5 L from the supply port and is closest to the discharge port. The gate is 0.5 L to 0.9 from the supply port.
It is provided at the position of L and the inner diameter of the gate on the discharge side is
It is smaller than the inner diameter of the gate on the side of the supply port or equal to the inner diameter of the gate on the side of the supply port, the inner diameter of the gate closest to the supply port is Da, and the inner diameter of the gate closest to the discharge port is Db. The kneading machine is characterized in that the ratio Da / Db of these inner diameters exceeds 1.0 and is 1.15 or less. 2. A kneading machine having a gate capable of adjusting the opening degree of a material passage to be kneaded in the kneading chamber, wherein the gates are provided at two or more locations, and a screw in the kneading chamber on the side of the material to be kneaded is supplied.
When the length of the kneading section from the end of the Leu shaft to the tip thereof is L, the gate closest to the supply port is provided at a position of 0.1 L to 0.5 L from the supply port and is closest to the discharge port. The gate is 0.5 L to 0.9 from the supply port.
It is provided at the position of L and the inner diameter of the gate on the discharge side is
It is smaller than the inner diameter of the gate on the side of the supply port, or is equal to the inner diameter of the gate on the side of the supply port, and the area of the gap between the barrel and the screw shaft is Oa. When the gap area between them is Ob, the ratio Oa / Ob of these is 2 to
A kneading machine characterized in that the number is 15.