JP2008097041A - Image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method for obtaining an image with a low gloss. <P>SOLUTION: The image forming method comprises a process where toner composed of a material mainly composed of a polyester based resin is fixed to a recording medium so as to form an image using a fixing device. The polyester based resin contains block polyester mainly composed of a block copolymer and amorphous polyester with crystallinity lower than that of the block polyester. The block polyester includes crystalline blocks obtained by condensing alcohol components and carboxylic acid components and amorphous blocks with crystallinity lower than that of the crystalline blocks. Provided that the weight average molecular weight of the block polyester is defined as Mw(B), and the weight average molecular weight of the amorphous polyester is defined as Mw(A), the relation of 0.5≤Mw(B)/Mw(A)<4 is satisfied, 4×10<SP>4</SP>≤Mw(B)≤3×10<SP>5</SP>is satisfied, and the blending ratio between the block polyester and the amorphous polyester is 5:95 to 35:65 by weigh ratio. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming method.

A number of methods are known as electrophotographic methods. In general, a process (exposure process) of forming an electrical latent image on a photoconductor by various means using a photoconductive substance, A developing process for developing the latent image with toner, a transfer process for transferring the toner image onto a transfer material such as paper, and a fixing process for fixing the toner image by heating using a fixing roller. Yes.
The toner used in the electrophotographic method as described above is generally composed of a material containing a resin as a main component (hereinafter also simply referred to as “resin”) and a colorant.

The resin contained in the toner can maintain the shape of the toner particles in the development process and the transfer process, and in the fixing process, it melts quickly and reliably fixes to the transfer material. From the viewpoint of energy saving and the like, development of a toner capable of fixing at a lower temperature (excellent in low-temperature fixability) is required.
As an attempt to obtain such a toner having excellent low-temperature fixability, for example, a method of increasing the low-temperature fixability by using a linear polyester as the main component of the binder resin is known (see, for example, Patent Document 1). ). Generally, when the main component of the binder resin is linear polyester as described above, the fixed image obtained by transferring the toner to the transfer material is glossy (high gloss). There is also a need to obtain a suppressed fixed image, that is, a low gloss image.
There have been various attempts to improve the low-temperature fixability of the toner, but it has been very difficult to produce a toner capable of obtaining a low gloss image. Further, when such toner is obtained, there is a problem that the fixing temperature becomes extremely high, and it is difficult to realize a low gloss image.

Japanese Patent No. 3064816 (first page, first to sixth lines)

  An object of the present invention is to provide an image forming method capable of obtaining a low gloss image.

Such an object is achieved by the present invention described below.
In the image forming method of the present invention, a recording medium that has passed through a fixing roller, a pressure roller pressed against the fixing roller, and a fixing nip formed by a contact portion between the fixing roller and the pressure roller is transferred to the recording medium. A fixing device having a peeling member for peeling from the fixing roller, and fixing the toner composed of a material mainly composed of a polyester resin on a recording medium to form an image,
The polyester resin includes a block polyester mainly composed of a block copolymer, and an amorphous polyester having lower crystallinity than the block polyester,
The block polyester has a crystalline block formed by condensing an alcohol component and a carboxylic acid component, and an amorphous block having lower crystallinity than the crystalline block,
When the weight average molecular weight of the block polyester is Mw (B) and the weight average molecular weight of the amorphous polyester is Mw (A), the relationship of 0.5 ≦ Mw (B) / Mw (A) <4 is satisfied. 4 × 10 ⁴ ≦ Mw (B) ≦ 3 × 10 ⁵
The blending ratio of the block polyester and the amorphous polyester is 5:95 to 35:65 by weight.
Thereby, an image forming method capable of obtaining a low gloss image can be provided. Further, the image can be reliably fixed on the recording medium, and the image can be prevented from being streaked or disturbed.

In the image forming method of the present invention, it is preferable that the fixing device has a recording medium feed speed of 0.05 to 1.0 m / sec.
Thereby, it is possible to more reliably prevent the image from causing streaking or disturbance.
In the image forming method of the present invention, it is preferable that the peeling member is a plate-like member having a predetermined length in the axial direction of the fixing roller and / or the pressure roller.
Thereby, the recording medium can be efficiently peeled from the fixing roller and the pressure roller.
In the image forming method of the present invention, it is preferable that the fixing device has the peeling member disposed on the downstream side of the fixing nip portion in the recording medium conveyance direction.
Thereby, the recording medium can be efficiently peeled from the fixing roller and the pressure roller.
In the image forming method of the present invention, it is preferable that the peeling member is disposed in the vicinity of the fixing roller and / or the pressure roller.
Thereby, the recording medium can be efficiently peeled from the fixing roller and the pressure roller.

In the image forming method of the present invention, it is preferable that the fixing device has the fixing roller and the pressure roller arranged in a substantially horizontal state.
This prevents streaks and disturbances in the image and improves the peelability of the recording medium.
In the image forming method of the present invention, it is preferable that the fixing device is provided with the peeling member so that a gap between the fixing roller and the peeling member is substantially constant during operation.
Thereby, the fall of the peelability of a recording medium can be prevented.

In the image forming method of the present invention, the peeling member is disposed along the axial direction of the fixing roller, and has a shape along the shape of the outlet of the fixing nip portion. preferable.
Thereby, the recording medium can be efficiently peeled from the fixing roller and the pressure roller.
In the image forming method of the present invention, the arrangement angle θ _A of the peeling member with respect to the tangent to the exit of the fixing nip portion is defined as a positive angle on the fixing roller side and a negative angle on the pressure roller side. It is preferably −5 to + 20 °.
This prevents streaks and disturbances in the image and improves the peelability of the recording medium.

In the image forming method of the present invention, the fixing device extends in the axial direction of the fixing roller and the pressure roller, and is arranged in the vicinity of the fixing roller on the downstream side of the fixing nip portion in the recording medium conveyance direction. A separation member disposed in proximity to the pressure roller, positioning the separation member on the fixing roller side on the surface of the fixing roller, and It is preferable that the peeling member is positioned on the bearing surface of the pressure roller.
Thereby, the peelability of the recording medium from the fixing roller and the pressure roller can be improved.

In the image forming method of the present invention, it is preferable that the fixing device has an axial length of the pressure roller shorter than that of the fixing roller, and the bearing is provided in an empty space.
Thereby, the peelability of the recording medium from the fixing roller and the pressure roller can be improved.

In the image forming method of the present invention, the fixing device is configured such that the gap G2 [μm] between the fixing roller and the peeling member in the vicinity of the end in the axial direction of the fixing roller is the central portion in the axial direction of the fixing roller. It is preferable that the gap is larger than the gap G1 [μm] between the fixing roller and the peeling member in the vicinity.
Thereby, gap management can be easily performed while maintaining the peelability of the recording medium.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.
The image forming method of the present invention includes a step of fixing an toner as described later on a recording medium and forming an image by a fixing device (image forming apparatus) as described later.
First, the toner applied to the present invention will be described.
FIG. 1 is a longitudinal cross-sectional view schematically showing an example of the configuration of a kneader and a cooler used in the production of toner applied to the present invention, and FIG. 2 is obtained when a differential scanning calorimetry analysis is performed on a block polyester. 3 is a model diagram of a differential scanning calorimetry curve near the melting point of the block polyester, FIG. 3 is a flow chart for softening point analysis, and FIG. 4 is an amount of rutile-anatase type titanium oxide released from toner particles contained in the toner. It is a figure for demonstrating the method to measure. Hereinafter, in FIG. 1, the left side is assumed to be “base end” and the right side is assumed to be “tip”.
The toner applied to the present invention contains at least a resin as a main component (hereinafter also simply referred to as “resin”).

Hereinafter, an example of a constituent material and a manufacturing method of a toner applied to the present invention will be described.
[Constituent materials]
The toner applied to the present invention can be manufactured using at least a raw material 5 containing a resin as a main component.
Hereafter, each component of the raw material 5 used for manufacture of the toner applied to this invention is demonstrated.

1. Resin (binder resin)
In the present invention, the resin (binder resin) is mainly composed of a polyester resin. The content of the polyester resin in the resin is preferably 50 wt% or more, and more preferably 80 wt% or more.
The polyester resin contains at least a block polyester as described below and an amorphous polyester. As described above, the present invention is characterized in that a block polyester and an amorphous polyester are used in combination.

1-1. Block polyester Block polyester is composed of a block copolymer having a crystalline block obtained by condensing an alcohol component and a carboxylic acid component, and an amorphous block having a lower crystallinity than the crystalline block. .
(1) Crystalline block The crystalline block has higher crystallinity than an amorphous block or amorphous polyester. That is, the molecular arrangement structure is stronger and more stable than amorphous blocks and amorphous polyesters. For this reason, the crystalline block contributes to improving the strength of the entire toner. As a result, the finally obtained toner is resistant to mechanical stress and has excellent durability and storage stability.

By the way, generally resin with high crystallinity has what is called sharp melt property compared with resin with low crystallinity. That is, a resin having high crystallinity has a property that when the endothermic peak of the melting point is measured by differential scanning calorimetry (DSC), the endothermic peak appears as a sharp shape compared to the resin having low crystallinity. Yes.
On the other hand, the crystalline block has high crystallinity as described above. Accordingly, the crystalline block has a function of imparting sharp melt properties to the block polyester. For this reason, the toner applied to the present invention maintains excellent shape stability even at relatively high temperatures (temperatures near the melting point of the block polyester) at which the amorphous polyester described later is sufficiently softened. can do. Therefore, the toner applied to the present invention can exhibit sufficient fixability (fixing strength) in a wide temperature range.
In addition, since the block polyester has such a crystalline block, in the present invention, when a thermal spheronization treatment as described later is performed, it can be performed efficiently (in a short time). In particular, the circularity of the toner particles obtained can be made particularly excellent.

Hereinafter, components constituting the crystalline block will be described.
As the alcohol component constituting the crystalline block, those having two or more hydroxyl groups can be used, and among them, an alcohol component having two hydroxyl groups is preferable. Examples of the alcohol component having two hydroxyl groups include aromatic diols having an aromatic ring structure and aliphatic diols having no aromatic ring structure. Examples of the aromatic diol include bisphenol A and alkylene oxide adducts of bisphenol A (for example, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3). ) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene ( 2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, etc.), and the aliphatic diol. Is, for example, ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3- Lopylene glycol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butane Diol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentane Diol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentane Diol, polyethylene glycol, polypropylene glycol, polytetramethylene Chain diols such as recall, or 2,2-bis (4-hydroxycyclohexyl) propane, alkylene oxide adducts of 2,2-bis (4-hydroxycyclohexyl) propane, 1,4-cyclohexanediol, 1,4 -Cyclohexane dimethanol, hydrogenated bisphenol A, cyclic diols such as hydrogenated bisphenol A alkylene oxide adducts, and the like.

  Examples of the alcohol component having three or more hydroxyl groups include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4- Butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethyl Examples include benzene.

  Thus, the alcohol component constituting the crystalline block is not particularly limited, but at least a part thereof is preferably an aliphatic diol, more preferably 80 mol% or more is an aliphatic diol, and 90 mol thereof. More preferably, at least% is an aliphatic diol. Thereby, the crystallinity of the block polyester (crystalline block) can be made particularly high, and the above-described effects become even more remarkable.

The alcohol component constituting the crystalline block has a linear molecular structure having 3 to 7 carbon atoms and has hydroxyl groups at both ends (general formula: HO— (CH ₂ ) _n —OH). It is preferable that the diol represented (however, n = 3-7) is included. By including such an alcohol component, the crystallinity is improved and the coefficient of friction is lowered, so that it is resistant to mechanical stress and particularly excellent in durability and storage stability. Examples of such diols include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and the like, among which 1,4-butanediol Is preferred. By including 1,4-butanediol, the above-described effects become particularly remarkable.
When 1,4-butanediol is included as an alcohol component constituting the crystalline block, 50 mol% or more of the alcohol component constituting the crystalline block is more preferably 1,4-butanediol, and 80 mol% or more thereof. More preferably, it is 1,4-butanediol. Thereby, the effect mentioned above becomes further remarkable.

As the carboxylic acid component constituting the crystalline block, a divalent or higher carboxylic acid or a derivative thereof (for example, an acid anhydride, a lower alkyl ester, etc.) can be used. Is preferably used. Examples of such divalent carboxylic acid components include o-phthalic acid (phthalic acid), terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, fumaric acid. Examples include acids, maleic acid, itaconic acid and derivatives thereof (for example, anhydrides, lower alkyl esters, etc.).
Examples of the trivalent or higher carboxylic acid component include trimellitic acid, pyromellitic acid, and derivatives thereof (for example, anhydride, lower alkyl ester and the like).

  As described above, the carboxylic acid component constituting the crystalline block is not particularly limited, but at least a part thereof preferably has a terephthalic acid skeleton, and 50 mol% or more thereof has a terephthalic acid skeleton. It is more preferable that 80 mol% or more of them has a terephthalic acid skeleton. Thereby, the finally obtained toner has a particularly excellent balance of various characteristics required for the toner. However, the “carboxylic acid component” here refers to the carboxylic acid component when the block polyester is used, and when preparing the block polyester (forming a crystalline block), the carboxylic acid component itself, Derivatives such as acid anhydrides and lower alkyl esters can be used.

Although the content rate of the crystalline block in block polyester is not specifically limited, It is preferable that it is 5-40 mol%, and it is more preferable that it is 10-30 mol%. If the content of the crystalline block is less than the lower limit, the effect of having the crystalline block as described above may not be sufficiently exhibited depending on the content of the block polyester. On the other hand, if the content of the crystalline block exceeds the above upper limit, the content of the amorphous block is relatively lowered, so that the compatibility between the block polyester and the amorphous polyester described later may be reduced. There is.
The crystalline block may include components other than the alcohol component and the carboxylic acid component as described above.

(2) Amorphous block The amorphous block has lower crystallinity than the crystalline block described above. Further, the amorphous polyester described later also has lower crystallinity than the crystalline block. That is, the amorphous block has a lower crystallinity than the crystalline block, as with the amorphous polyester described later.
By the way, in a blend resin, in general, resins having greatly different crystallinities are hardly compatible with each other, and resins having a small difference in crystallinity are easily compatible with each other. Therefore, when the block polyester has an amorphous block, compatibility (dispersibility) between the block polyester and the amorphous polyester described later is increased. As a result, it is possible to effectively prevent phase separation (particularly macrophase separation) between the block polyester and the amorphous polyester in the finally obtained toner. The advantages of polyester can be exhibited sufficiently and stably.

Hereinafter, the components constituting the amorphous block will be described.
As the alcohol component constituting the amorphous block, one having two or more hydroxyl groups can be used, and among them, an alcohol component having two hydroxyl groups is preferable. Examples of the alcohol component having two hydroxyl groups include aromatic diols having an aromatic ring structure and aliphatic diols having no aromatic ring structure. Examples of the aromatic diol include bisphenol A and alkylene oxide adducts of bisphenol A (for example, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3). ) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene ( 2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, etc.), and the aliphatic diol. Is, for example, ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3- Lopylene glycol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butane Diol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentane Diol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentane Diol, polyethylene glycol, polypropylene glycol, polytetramethylene Chain diols such as recall, or 2,2-bis (4-hydroxycyclohexyl) propane, alkylene oxide adducts of 2,2-bis (4-hydroxycyclohexyl) propane, 1,4-cyclohexanediol, 1,4 -Cyclohexane dimethanol, hydrogenated bisphenol A, cyclic diols such as hydrogenated bisphenol A alkylene oxide adducts, and the like.

  Examples of the alcohol component having three or more hydroxyl groups include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4- Butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethyl Examples include benzene.

Thus, although the alcohol component which comprises an amorphous block is not specifically limited, It is preferable that at least one part is an aliphatic diol, and it is more preferable that 50 mol% or more is an aliphatic diol. Thereby, an effect that a fixed image having better toughness (excellent bending resistance) can be obtained can be obtained.
Moreover, it is preferable that at least a part of the alcohol component constituting the amorphous block has a branched chain (side chain), and more preferably 30 mol% or more thereof has a branched chain. Thereby, the effect that the regular arrangement is suppressed, the crystallinity is lowered, and the transparency is improved is obtained.

As the carboxylic acid component constituting the amorphous block, a divalent or higher carboxylic acid or a derivative thereof (for example, an acid anhydride, a lower alkyl ester, etc.) can be used. Etc. are preferably used. Examples of such divalent carboxylic acid components include o-phthalic acid (phthalic acid), terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, fumaric acid. Examples include acids, maleic acid, itaconic acid and derivatives thereof (for example, anhydrides, lower alkyl esters, etc.).
Examples of the trivalent or higher carboxylic acid component include trimellitic acid, pyromellitic acid, and derivatives thereof (for example, anhydride, lower alkyl ester and the like).

As described above, the carboxylic acid component constituting the amorphous block is not particularly limited, but at least a part thereof preferably has a terephthalic acid skeleton, and 80 mol% or more thereof has a terephthalic acid skeleton. More preferably. Thereby, the finally obtained toner has a particularly excellent balance of various characteristics required for the toner. However, the “carboxylic acid component” here refers to the carboxylic acid component when the block polyester is used, and when preparing the block polyester (forming an amorphous block), the carboxylic acid component itself or In addition, derivatives such as acid anhydrides and lower alkyl esters thereof can be used.
The amorphous block may contain components other than the alcohol component and carboxylic acid component as described above.

In the present invention, the average molecular weight (weight average molecular weight) Mw (B) of the block polyester having a crystalline block and an amorphous block as described above is 4 × 10 ⁴ ≦ Mw (B) ≦ 3 × 10 ⁵ . It is characterized by that. As a result, the finally obtained toner can provide an image with sufficiently suppressed gloss (low gloss). In particular, in the present invention, a low gloss image can be obtained at a relatively high fixing temperature. On the other hand, when the average molecular weight Mw (B) is less than the lower limit, it is difficult to obtain a desired gloss image (low gloss image). Further, the mechanical strength of the finally obtained toner is lowered, and there is a possibility that sufficient durability (storability) cannot be obtained. Furthermore, if the average molecular weight Mw (B) is too small, it tends to cause cohesive failure at the time of fixing the toner and tends to decrease the offset resistance. On the other hand, if the average molecular weight Mw (B) exceeds the above upper limit value, it becomes easy to cause grain boundary destruction at the time of fixing the toner, the wettability to a transfer material (recording medium) such as paper is reduced, and the amount of heat required for fixing is also reduced. growing.
Thus, in the present invention, the average molecular weight (weight average molecular weight) Mw (B) of the block polyester is 4 × 10 ⁴ ≦ Mw (B) ≦ 3 × 10 ⁵ , but 4 × 10 ⁴ ≦ Mw (B) ≦ 1.5 × 10 ⁵ is preferable, and 5 × 10 ⁴ ≦ Mw (B) ≦ 1 × 10 ⁵ is more preferable. Thereby, the effect of this invention becomes remarkable.

Glass transition point _{T g} of the block polyester is not particularly limited, but is preferably 50 to 80 ° C., and more preferably 55 to 75 ° C.. When the glass transition point is less than the lower limit, the storage stability (heat resistance) of the toner is lowered, and fusion between toner particles may occur depending on the use environment or the like. On the other hand, when the glass transition point exceeds the upper limit, low-temperature fixability and transparency are deteriorated. On the other hand, if the glass transition point is too high, the effect may not be sufficiently exhibited when a thermal spheronization treatment as described later is performed. The glass transition point can be measured according to JIS K7121.

Although the softening point T1 _{/ 2} of block polyester is not specifically limited, It is preferable that it is 90-180 degreeC, and it is more preferable that it is 100-160 degreeC. If the softening point is less than the lower limit, the storage stability as a toner may be reduced, and sufficient durability may not be obtained. On the other hand, if the softening point is too low, cohesive failure is likely to occur at the time of fixing the toner, and the offset resistance tends to decrease. On the other hand, if the softening point exceeds the upper limit, grain boundary breakage is likely to occur during toner fixing, the wettability to a transfer material (recording medium) such as paper also decreases, and the amount of heat required for fixing increases. The softening point T1 _{/ 2} is, for example, a flow tester, sample amount: 1 g, die hole diameter: 1 mm, die length: 1 mm, load: 20 kgf, preheating time: 300 seconds, measurement start temperature: 50 ° C., It can be obtained as the temperature of a point on the flow curve corresponding to h / 2 in the flowchart for analysis as shown in FIG.

The melting point T _{m of the} block polyester (the center value T _mp of the peak when measuring the endothermic peak of the melting point by differential scanning calorimetry described later) is not particularly limited, but is preferably 190 ° C. or higher. More preferably, it is 230 degreeC. When the melting point is less than 190 ° C., there is a possibility that effects such as improvement in offset resistance cannot be sufficiently obtained. On the other hand, if the melting point is too high, the material temperature must be relatively high in the kneading step described later. As a result, the transesterification reaction of the resin material tends to proceed, and it may be difficult to sufficiently reflect the resin design in the finally obtained toner. In addition, melting | fusing point can be calculated | required by the measurement of the endothermic peak by differential scanning calorimetry (DSC), for example.

When the finally obtained toner is used in a fixing device having a fixing roller as described later, the melting point of the block polyester is T _m (B) [° C.], and the standard set temperature of the surface of the fixing roller _Is T _fix [° C.], it is preferable to satisfy the relationship of T _fix ≦ T _m (B) ≦ (T _fix +100), and (T _fix +10) ≦ T _m (B) ≦ (T _fix +70) It is more preferable to satisfy this relationship. By satisfying such a relationship, the crystalline component in the toner is not melted at the time of fixing the toner, so that the toner viscosity does not decrease below a certain level and the releasability from the fixing roller is ensured.

  Moreover, it is preferable that melting | fusing point of block polyester is higher than the softening point of the amorphous polyester mentioned later. As a result, the stability of the finally obtained toner shape is improved, and particularly excellent stability against mechanical stress is exhibited. In addition, when the melting point of the block polyester is higher than the softening point of the amorphous polyester described later, for example, when the thermal spheronization process described later is performed, the shape of the powder for toner production is secured to some extent by the block polyester. However, the amorphous polyester can be sufficiently softened. As a result, the thermal spheronization treatment can be performed efficiently, and the circularity of the finally obtained toner (toner particles) can be made relatively easy.

By the way, as described above, the block polyester used in the present invention has a crystalline block with high crystallinity, and therefore, compared with a resin material with relatively low crystallinity (for example, amorphous polyester described later). Thus, it has a so-called sharp melt property.
As an index representing crystallinity, for example, the end value of the melting point is measured by differential scanning calorimetry (DSC), the center value of the peak is T _mp [° C.], and the shoulder peak value is T _ms [° C.]. In this case, a ΔT value represented by ΔT = T _mp −T _ms can be cited (see FIG. 2). The smaller this ΔT value, the higher the crystallinity.

The ΔT value of the block polyester is preferably 50 ° C. or lower, and more preferably 20 ° C. or lower. The measurement conditions of T _mp [° C.] and T _ms [° C.] are not particularly limited. For example, the sample block polyester is heated to 200 ° C. at a temperature increase rate of 10 ° C./min. After the temperature is lowered at 10 ° C./min, the temperature can be measured by raising the temperature at a rate of temperature rise: 10 ° C./min.

Moreover, block polyester has higher crystallinity than the amorphous polyester mentioned later. Therefore, when the ΔT value of the amorphous polyester is ΔT _A [° C.] and the ΔT value of the block polyester is ΔT _B [° C.], the relationship of ΔT _A > ΔT _B is satisfied. In particular, in the present invention, it is preferable to satisfy the relationship of ΔT _A −ΔT _B > 10, and it is more preferable to satisfy the relationship of ΔT _A −ΔT _B > 30. By satisfying such a relationship, the above-described effect becomes more remarkable. However, if particularly low crystallinity of the amorphous polyester, there may T _mp, or at least one of T _ms is difficult to measure (determination difficult). In this case, [Delta] T _A is set to ∞ [° C.].

The block polyester preferably has a heat of fusion E _f obtained by measuring an endothermic peak of a melting point by differential scanning calorimetry of 3 mJ / mg or more, and more preferably 12 mJ / mg or more. When the heat of fusion E _f is less than 3 mJ / mg, the effect as described above may not be sufficiently exhibited by having a crystalline block. However, the heat of fusion does not include the heat quantity of the endothermic peak at the glass transition point (see FIG. 2). The measurement conditions for the endothermic peak of the melting point are not particularly limited. For example, the block polyester as a sample was heated to 200 ° C. at a rate of temperature increase: 10 ° C./min, and further decreased at a rate of temperature decrease: 10 ° C./min. Then, the value measured when the temperature is raised at a rate of temperature rise of 10 ° C./min can be determined as the heat of fusion.
Moreover, it is preferable that block polyester is a linear type polymer (polymer which does not have a crosslinked structure). The linear polymer has a smaller coefficient of friction than the cross-linked polymer. Thereby, particularly excellent releasability is obtained, and the transfer efficiency of the toner is further improved.

The block polyester may be used in combination of two or more resins (block polyesters) having different types and blending ratios of monomer components (alcohol component, carboxylic acid component, etc.) constituting the block polyester. The average molecular weight Mw (B) as the block polyester in this case refers to an average value obtained from the average molecular weight and blending ratio of each resin (block polyester).
In addition, block polyester may have blocks other than the crystalline block mentioned above and an amorphous block.

1-2. Amorphous polyester The amorphous polyester has a lower crystallinity than the block polyester described above.
Amorphous polyester is mainly composed of the dispersibility of each component constituting the toner (for example, a colorant, wax, antistatic agent, etc., which will be described later), the pulverization property of the kneaded product during toner production, and the toner fixing property. It is a component that contributes to improving functions such as (especially low-temperature fixability), transparency, mechanical properties (for example, elasticity, mechanical strength, etc.), chargeability, and moisture resistance. In other words, if the amorphous polyester as described in detail below is not contained in the toner, it is difficult to sufficiently exhibit the characteristics required for the toner as described above.

Hereinafter, the components constituting the amorphous polyester will be described.
As the alcohol component constituting the amorphous polyester, those having two or more hydroxyl groups can be used, and among them, an alcohol component having two hydroxyl groups is preferable. Examples of the alcohol component having two hydroxyl groups include aromatic diols having an aromatic ring structure and aliphatic diols having no aromatic ring structure. Examples of the aromatic diol include bisphenol A and alkylene oxide adducts of bisphenol A (for example, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3). ) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene ( 2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, etc.), and the aliphatic diol. Is, for example, ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3- Lopylene glycol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butane Diol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentane Diol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentane Diol, polyethylene glycol, polypropylene glycol, polytetramethylene Chain diols such as recall, or 2,2-bis (4-hydroxycyclohexyl) propane, alkylene oxide adducts of 2,2-bis (4-hydroxycyclohexyl) propane, 1,4-cyclohexanediol, 1,4 -Cyclohexane dimethanol, hydrogenated bisphenol A, cyclic diols such as hydrogenated bisphenol A alkylene oxide adducts, and the like.

  Examples of the alcohol component having three or more hydroxyl groups include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4- Butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethyl Examples include benzene.

As the carboxylic acid component constituting the amorphous polyester, divalent or higher carboxylic acids or derivatives thereof (for example, acid anhydrides, lower alkyl esters, etc.) can be used. Etc. are preferably used. Examples of such divalent carboxylic acid components include o-phthalic acid (phthalic acid), terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, fumaric acid. Examples include acids, maleic acid, itaconic acid and derivatives thereof (for example, anhydrides, lower alkyl esters, etc.).
Examples of the trivalent or higher carboxylic acid component include trimellitic acid, pyromellitic acid, and derivatives thereof (for example, anhydride, lower alkyl ester and the like).

  Thus, the carboxylic acid component constituting the amorphous polyester is not particularly limited, but at least a part thereof preferably has a terephthalic acid skeleton, and 80 mol% or more thereof has a terephthalic acid skeleton. More preferably, 90 mol% or more of them has a terephthalic acid skeleton. Thereby, the finally obtained toner has a particularly excellent balance of various characteristics required for the toner. However, the “carboxylic acid component” here refers to the carboxylic acid component when the amorphous polyester is used, and when preparing the amorphous polyester, the carboxylic acid component itself or its acid anhydride is used. In addition, a derivative such as a lower alkyl ester can be used.

Moreover, it is preferable that 50 mol% or more (more preferably 80 mol% or more) of the monomer component constituting the amorphous polyester is the same as the monomer component constituting the amorphous block described above. That is, the amorphous polyester is preferably composed of the same monomer component as the amorphous block. Thereby, the compatibility between the amorphous polyester and the block polyester is particularly excellent. However, the “monomer component” here does not refer to a monomer used for producing an amorphous polyester or block polyester, but refers to a monomer component contained in the amorphous polyester or block polyester.
In addition, amorphous polyester may contain components other than the above alcohol components and carboxylic acid components.

Average molecular weight of the amorphous polyester (a weight-average molecular weight) Mw (A) is not particularly limited, but is preferably ^{1 × 10 4 ~8 × 10 4} , 1 × 10 4 ~4 × 10 is the ^four Is more preferable. If the average molecular weight Mw (A) is less than the lower limit, the mechanical strength of the finally obtained toner is lowered, and sufficient durability (storability) may not be obtained. On the other hand, if the average molecular weight Mw (A) is too small, cohesive failure is likely to occur at the time of fixing the toner, and the offset resistance tends to decrease. On the other hand, when the average molecular weight Mw exceeds the above upper limit, grain boundary breakage is liable to occur at the time of toner fixing, the wettability to a transfer material (recording medium) such as paper is reduced, and the amount of heat required for fixing is increased.

In the present invention, when the weight average molecular weight of the block polyester is Mw (B) and the weight average molecular weight of the amorphous polyester is Mw (A), 0.5 ≦ Mw (B) / Mw (A) <4. It is characterized by satisfying the relationship. When Mw (B) / Mw (A) satisfies such a relationship, the finally obtained toner can provide an image with sufficiently reduced gloss (low gloss). In particular, in the present invention, a low gloss image can be obtained at a relatively high fixing temperature. On the other hand, if Mw (B) / Mw (A) is less than the lower limit, grain boundary breakage is liable to occur during toner fixing, and wettability to a transfer material (recording medium) such as paper also decreases. The amount of heat required for fixing is also increased. Further, if Mw (B) / Mw (A) exceeds the upper limit, a desired gloss image (low gloss image) may not be obtained. Further, the mechanical strength of the finally obtained toner is lowered, and there is a possibility that sufficient durability (storability) cannot be obtained.
As described above, according to the present invention, Mw (B) / Mw (A) satisfies the above relationship, but satisfies the relationship of 1.5 ≦ Mw (B) / Mw (A) <4. Preferably, it is more preferable to satisfy the relationship of 2.5 ≦ Mw (B) / Mw (A) <4. Thereby, the effect of this invention becomes remarkable.

  In particular, the present invention is characterized in that the relationship between the weight average molecular weight of the amorphous polyester and the block polyester as described above and the range of the weight average molecular weight of the block polyester are satisfied at the same time. By satisfying these conditions at the same time, the final toner has a sufficiently low gloss image while maintaining sufficient fixability (fixing strength) and sufficient mechanical strength. Can be provided. In particular, in the present invention, a low gloss image can be obtained at a relatively high fixing temperature. Further, when used in a fixing device as will be described later, the above-described effects become remarkable.

Glass transition point _{T g} of the amorphous polyester is not particularly limited, but is preferably 50 to 75 ° C., and more preferably 50-65 ° C.. When the glass transition point is less than the lower limit, the storage stability (heat resistance) of the toner is lowered, and fusion between toner particles may occur depending on the use environment or the like. On the other hand, when the glass transition point exceeds the upper limit, low-temperature fixability and transparency are deteriorated. On the other hand, if the glass transition point is too high, the effect may not be sufficiently exhibited when a thermal spheronization treatment as described later is performed. The glass transition point can be measured according to JIS K7121.

The softening point T _1/2 of the amorphous polyester is not particularly limited, but is preferably 90 to 160 ° C, more preferably 90 to 140 ° C, and further preferably 90 to 120 ° C. If the softening point is less than the lower limit, the storage stability as a toner may be reduced, and sufficient durability may not be obtained. On the other hand, if the softening point is too low, cohesive failure is likely to occur at the time of fixing the toner, and the offset resistance tends to decrease. On the other hand, if the softening point exceeds the upper limit, grain boundary breakage is likely to occur during toner fixing, the wettability to a transfer material (recording medium) such as paper also decreases, and the amount of heat required for fixing increases.

When the softening point of the amorphous polyester is T _1/2 (A) [° C.] and the melting point of the block polyester is T _m (B), T _m (B)> (T _1/2 (A ) +60), and more preferably (T _1/2 (A) +60) <T _m (B) <(T _1/2 (A) +150). By satisfying such a relationship, for example, when a thermal spheronization process as described later is performed, it can be performed more efficiently, and the circularity of the toner (particles) obtained can be further improved. Further, by satisfying the relationship as described above, the toner can exhibit excellent fixability in a wider temperature range.

The softening point T1 _{/ 2} is, for example, a flow tester, sample amount: 1 g, die hole diameter: 1 mm, die length: 1 mm, load: 20 kgf, preheating time: 300 seconds, measurement start temperature: 50 ° C., It can be obtained as the temperature of a point on the flow curve corresponding to h / 2 in the flowchart for analysis as shown in FIG.

The amorphous polyester is preferably a linear polymer (a polymer having no cross-linked structure). The linear polymer has a smaller coefficient of friction than the cross-linked polymer. Thereby, particularly excellent releasability is obtained, and the transfer efficiency of the toner is further improved.
In addition, the amorphous polyester is a combination of two or more kinds of resins (amorphous polyester) having different types and blending ratios of monomer components (alcohol component, carboxylic acid component, etc.) constituting the amorphous polyester. It may be used. In this case, the average molecular weight Mw (A) as the amorphous polyester refers to an average value determined by the average molecular weight and the blending ratio of each resin (amorphous polyester).
When two or more kinds of amorphous polyesters are used, for example, at least one may have a relatively high acid value. If such a high acid value is contained in a relatively small amount, it is possible to improve the fixing property and charging property while maintaining sufficient environmental properties.

  As described above, the present invention is characterized in that a block polyester that satisfies the above-described relationship and an amorphous polyester are used in combination. This makes it possible to achieve both the features of the block polyester and the features of the amorphous polyester as described above. Further, the finally obtained toner can provide an image with sufficiently suppressed gloss (low gloss) while maintaining sufficient fixability (fixing strength) and sufficient mechanical strength. . In particular, in the present invention, a low gloss image can be obtained at a relatively high fixing temperature. Further, when used in a fixing device as will be described later, the above-described effects become remarkable.

Such a synergistic effect cannot be obtained when only one of the block polyester and the amorphous polyester is used.
That is, when only the block polyester is used (when the amorphous polyester is not included in the toner), the fixability of the toner (particularly, the fixability in a low temperature region) is lowered. Further, when only the block polyester is used (when the amorphous polyester is not included in the toner), functions such as transparency of the toner are lowered, and each component constituting the toner (for example, as described later) The dispersibility of the colorant, wax, antistatic agent, etc.) and the pulverizability of the kneaded product during toner production are also reduced.

  Further, when only amorphous polyester is used (when the block polyester is not included in the toner), the finally obtained toner is weak against mechanical stress, and sufficient durability cannot be obtained. In addition, when only amorphous polyester is used (when the block polyester is not included in the toner), a sharp melt property cannot be obtained, so sufficient fixability (fixing strength) in a wide temperature range (especially in a high temperature range). ) Is difficult to ensure, and, for example, when performing a thermal spheronization process, which will be described later, it is difficult to perform efficiently, and the circularity of the finally obtained toner particles is set to an appropriate value. It becomes difficult.

  By the way, polyester having high crystallinity (hereinafter referred to as “crystalline polyester”) generally has a stable molecular arrangement structure, so that the strength as a toner is improved even if it is not a block polyester as described above. It can be made strong against mechanical stress. However, the crystalline polyesters other than the block polyester as described above are inferior in compatibility with the amorphous polyester, and are likely to cause phase separation when used in combination with the amorphous polyester. Therefore, when the crystalline polyester other than the block polyester and the amorphous polyester are used in combination without using the block polyester, the synergistic effect of using the block polyester and the amorphous polyester as described above. There is no effect.

  The blending ratio of the block polyester and the amorphous polyester is preferably 5:95 to 35:65 by weight, and more preferably 5:95 to 25:75. Thus, in this invention, it is preferable that the compounding ratio of block polyester is comparatively low. If the blending ratio of the block polyester becomes too low, it may be difficult to sufficiently improve the offset resistance of the toner. On the other hand, if the blending ratio of amorphous polyester is too low, sufficient low-temperature fixability and transparency may not be obtained. If the blending ratio of the amorphous polyester is too low, for example, it becomes difficult to pulverize the kneaded material 7 efficiently and uniformly in the pulverization step of the toner production method as described later.

In addition, the resin (binder resin) may include a component (third resin component) other than the above-described block polyester and amorphous polyester.
Examples of the resin component (third resin component) other than the block polyester and the amorphous polyester include polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, Styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene -Styrene resin such as acrylic ester-methacrylic ester copolymer, styrene-α-chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylic ester copolymer, styrene-vinyl methyl ether copolymer Or containing styrene substitution Homopolymer or copolymer, polyester resin (the above-mentioned crystalline polyester having higher crystallinity than block polyester), epoxy resin, urethane-modified epoxy resin, silicone-modified epoxy resin, vinyl chloride resin, rosin-modified Maleic acid resin, phenyl resin, polyethylene, polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, terpene resin, phenol resin, aliphatic or alicyclic A hydrocarbon resin etc. are mentioned, Among these, it can use 1 type or in combination of 2 or more types.

  The content of the resin in the raw material 5 is not particularly limited, but is preferably 50 to 98 wt%, and more preferably 85 to 97 wt%. If the resin content is less than the lower limit, the function of the resin (for example, good fixability in a wide temperature range) may not be sufficiently exhibited in the finally obtained toner. On the other hand, when the resin content exceeds the upper limit, the content of components other than the resin such as the colorant is relatively lowered, and it becomes difficult to sufficiently exhibit toner characteristics such as color development.

2. Colorant As the colorant, for example, pigments, dyes and the like can be used. Examples of such pigments and dyes include carbon black, spirit black, lamp black (CI No. 77266), magnetite, titanium black, chrome lead, cadmium yellow, mineral fast yellow, navel yellow, and naphthol yellow S. , Hansa Yellow G, Permanent Yellow NCG, Chrome Yellow, Benzidine Yellow, Quinoline Yellow, Tartrazine Lake, Red Mouth Lead, Molybdenum Orange, Permanent Orange GTR, Pyrazolone Orange, Benzidine Orange G, Cadmium Red, Permanent Red 4R, Watching Red Calcium salt, eosin lake, brilliant carmine 3B, manganese purple, fast violet B, methyl violet lake, bitumen, cobalt blue, al Reblue Lake, Victoria Blue Lake, First Sky Blue, Indanthrene Blue BC, Ultramarine, Aniline Blue, Phthalocyanine Blue, Calco Oil Blue, Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, Phthalocyanine Green, Final Yellow Green G, Rhodamine 6G, quinacridone, rose bengal (C.I. No. 45432), C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 184, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 5: 1, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Basic Green 6, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 162, nigrosine dye (CI No. 50415B), metal complex dye, silica, aluminum oxide, magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, Examples thereof include metal oxides such as magnesium oxide, and magnetic materials containing magnetic metals such as Fe, Co, and Ni, and one or more of these can be used in combination.

  The content of the colorant in the raw material 5 is not particularly limited, but is preferably 1 to 10 wt%, and more preferably 3 to 8 wt%. If the content of the colorant is less than the lower limit, it may be difficult to form a visible image having a sufficient density depending on the type of the colorant. On the other hand, when the content of the colorant exceeds the upper limit, the content of the resin is relatively lowered, and the fixing property to a transfer material (recording medium) such as paper at a necessary color density is lowered.

3. Wax In addition, the raw material 5 used for manufacturing the toner may contain a wax as necessary.
By including the wax, for example, the releasability of the toner particles can be improved.

  Examples of the wax include hydrocarbon waxes such as ozokerite, cercin, paraffin wax, microwax, microcrystalline wax, petrolatum, Fischer-Tropsch wax, carnauba wax, rice wax, methyl laurate, methyl myristate, palmitic acid. Methyl, methyl stearate, butyl stearate, candelilla wax, cotton wax, wood wax, beeswax, lanolin, montan wax, fatty acid ester ester wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax Olefin waxes such as 12-hydroxy stearamide, stearamide, phthalic anhydride amide wax, Lauro , Ketone waxes such as stearone, ether waxes, and the like, can be used singly or in combination of two or more of them.

Among the materials described above, the following effects can be obtained particularly when ester wax (for example, carnauba wax or rice wax) is used.
The ester wax has an ester structure in the molecule similarly to the polyester resin described above, and is excellent in compatibility with the polyester resin. Further, as described above, the polyester-based resin is excellent in compatibility with the resin as the main component. For this reason, generation and coarsening of free wax in the finally obtained toner particles can be prevented (fine dispersion and microphase separation of the wax in the toner can be easily achieved). As a result, the finally obtained toner has particularly excellent releasability from the fixing roller.

Melting _{T m} of a wax is not particularly limited, but is preferably 30 to 160 ° C., and more preferably 50 to 100 ° C.. The melting point _Tm is determined by, for example, differential heating calorimetry (DSC), the temperature rising rate is 10 ° C./min to 200 ° C., the temperature decreasing rate is 10 ° C./min, : The value measured when the temperature is raised at 10 ° C./min can be obtained as the heat of fusion.

4). Other Components The raw material 5 may contain components other than the resin, the colorant, and the wax. Examples of such components include a charge control agent, a dispersant, and magnetic powder.
Examples of the charge control agent include benzoic acid metal salts, salicylic acid metal salts, alkyl salicylic acid metal salts, catechol metal salts, metal-containing bisazo dyes, nigrosine dyes, tetraphenylborate derivatives, quaternary ammonium salts, Examples thereof include alkyl pyridinium salts, chlorinated polyesters, and nitrofunic acid.

Examples of the dispersant include metal soaps, inorganic metal salts, organic metal salts, and polyethylene glycol.
Examples of the metal soap include tristearic acid metal salts (for example, aluminum salts), distearic acid metal salts (for example, aluminum salts, barium salts, etc.), stearic acid metal salts (for example, calcium salts, lead salts, zinc salts, etc.) ), Linolenic acid metal salts (eg, cobalt salts, manganese salts, lead salts, zinc salts, etc.), octanoic acid metal salts (eg, aluminum salts, calcium salts, cobalt salts, etc.), oleic acid metal salts (eg, calcium salts) , Cobalt salts, etc.), palmitic acid metal salts (eg, zinc salts, etc.), naphthenic acid metal salts (eg, calcium salts, cobalt salts, manganese salts, lead salts, zinc salts, etc.), resin acid metal salts (eg, calcium Salt, cobalt salt, manganese lead salt, zinc salt, etc.).

  Examples of the inorganic metal salt and the organic metal salt include a cation of an element selected from the group consisting of metals of Group IA, Group IIA, and Group IIIA of the periodic table as a cationic component, and an anion Examples of the property component include salts containing an anion selected from the group consisting of halogen, carbonate, acetate, sulfate, borate, nitrate, and phosphate.

Examples of the magnetic powder include magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, magnesium oxide, and other metal oxides such as Fe, Co, and Ni. The thing comprised with the magnetic material containing a magnetic metal etc. are mentioned.
In addition to the above materials, for example, zinc stearate, zinc oxide, cerium oxide, or the like may be used as an additive.

[Kneading process]
The raw material 5 as described above is kneaded using a kneader 1 as shown in FIG.
It is preferable that the raw material 5 used for kneading is prepared by previously mixing the above-described components.
This embodiment demonstrates the structure which uses a biaxial kneading extruder as a kneading machine.
The kneading machine 1 includes a process unit 2 for kneading while conveying the raw material 5, a head unit 3 for extruding the kneaded raw material (kneaded material 7) in a predetermined cross-sectional shape, and the raw material 5 in the process unit 2. And a feeder 4 to be supplied.

The process unit 2 includes a barrel 21, a screw 22 and a screw 23 inserted into the barrel 21, and a fixing member 24 for fixing the head unit 3 to the tip of the barrel 21.
In the process part 2, the screw 22 and the screw 23 rotate to apply a shearing force to the raw material 5 supplied from the feeder 4, and the uniform kneaded material 7, in particular, the block polyester and the amorphous polyester are sufficient. To obtain a kneaded material 7 which is compatible with each other.

  The total length of the process part 2 is preferably 50 to 300 cm, and more preferably 100 to 250 cm. If the total length of the process part 2 is less than the lower limit value, it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester. On the other hand, if the total length of the process unit 2 exceeds the upper limit, depending on the temperature in the process unit 2, the number of rotations of the screw 22 and the screw 23, the raw material 5 is likely to be denatured by heat, and the finally obtained toner It may be difficult to sufficiently control the physical properties of the material.

In addition, the process unit 2 includes a first region 25 having a predetermined length in the longitudinal direction, and a second region 26 provided on the head unit 3 side from the first region 25. That is, the raw material 5 passes through the first region 25 and then is fed into the second region 26.
The internal temperature of the first region 25 is set higher than that of the second region 26. That is, in other words, the temperature of the raw material 5 transported inside the process unit 2 when passing through the first region 25 is higher than the temperature when passing through the second region 26.
As described above, in the first region 25, the raw material 5 is kneaded at a relatively high temperature, so that the block polyester and the amorphous polyester can be sufficiently compatible.

The raw material temperature (the internal temperature of the first region 25) T ₁ [° C.] in the first region 25 is T _m (B) ≦ when the melting point of the block polyester is T _m (B) [° C.]. It is preferable to satisfy the relationship at T _{1, and} it is more preferable to satisfy the relationship of (T _m (B) + 10 ° C.) ≦ T ₁ ≦ (T _m (B) + 60 ° C.). If the raw material temperature T ₁ is less than T _m (B) [° C.], it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester.

The specific value of the material temperature _{T 1} of the first region 25 within, varies depending on the composition of the resin is preferably from one hundred ninety to three hundred ° C., and more preferably 200 to 250 ° C..
Further, in the first region 25 within the starting temperature T ₁ of, even uniform, it may be different by site. In the latter case, the maximum temperature of the raw material 5 in the first region 25 is preferably higher than the lower limit value, and the minimum temperature and the maximum temperature of the raw material 5 in the first region 25 are within the above range. More preferably.

  The residence time (time required for passage) of the raw material 5 in the first region 25 is preferably 0.5 to 12 minutes, and more preferably 0.5 to 7 minutes. If the residence time in the first region 25 is less than the lower limit value, it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester. On the other hand, if the residence time in the first region 25 exceeds the upper limit value, the production efficiency is lowered, and depending on the temperature in the process unit 2, the number of rotations of the screw 22, the screw 23, etc., the raw material due to heat 5 may easily occur, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.

  Moreover, it is preferable that the length of the 1st area | region 25 is 10-200 cm, and it is more preferable that it is 20-150 cm. If the length of the first region 25 is less than the lower limit value, it may be difficult to make the block polyester and the amorphous polyester sufficiently compatible. On the other hand, when the length of the first region 25 exceeds the upper limit value, the production efficiency is lowered, and depending on the temperature in the process unit 2, the rotational speed of the screw 22, the screw 23, etc., the raw material 5 due to heat is reduced. This tends to cause modification, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.

  By the way, in the 1st area | region 25, block polyester and amorphous polyester are fully compatibilized by knead | mixing at comparatively high temperature. However, since the block polyester and the amorphous polyester are resins having molecular structures that are greatly different from each other, even if the block polyester and the amorphous polyester are sufficiently compatible, the kneaded product is cooled. Depending on conditions, block polyester and amorphous polyester may cause phase separation.

Therefore, in the present embodiment, the second region 26 is provided and kneaded at a relatively lower temperature than the first region 25 as in the configuration shown in the drawing. Thereby, the dispersion | distribution failure of each component of the kneaded material 7 and generation | occurrence | production of phase separation can be prevented effectively. Further, when the raw material 5 contains a wax (especially a wax having low compatibility with the resin), the coarsening of the wax in the kneaded product 7 can be prevented, and the wax is finely adjusted to an appropriate particle size. Can be dispersed. As a result, the obtained kneaded product 7 can effectively suppress a decrease in grindability, and the finally obtained toner can suppress a decrease in transparency and durability and occurrence of offset. can do. Further, with respect to the toner, since the respective constituent components in the kneaded product 7 are uniformly dispersed, there is little variation in the characteristics among the toner particles, and the overall characteristics can be improved. . Therefore, the effect of each constituent component can be sufficiently exhibited.
In particular, by providing the first region 25 and the second region 26 as described above, the crystallization of the block polyester is efficiently advanced while sufficiently preventing phase separation in the second region 26. Therefore, the finally obtained toner is resistant to mechanical stress.

The raw material temperature (the internal temperature of the second region 26) T ₂ [° C.] in the second region 26 is (2) when the softening point of the amorphous polyester is T _1/2 (A) [° C.] It is preferable to satisfy the relationship of T _1/2 (A) -20) ≦ T ₂ ≦ (T _1/2 (A) +20), and (T _1/2 (A) −10) ≦ T ₂ ≦ (T _It is more preferable to satisfy the relationship of _1/2 (A) +10). Feed temperature T ₂ is less than the above lower limit value, with the phase separation or the like in the kneaded material 7 is likely to occur, and lowers the fluidity of the block polyester and the amorphous polyester, the toner productivity is degraded There is a case. On the other hand, if the material temperature T ₂ exceeds the above upper limit value, the effect obtained by providing the second region 26 it may not be sufficiently obtained.

The specific value of the material temperature _{T 2} within the second region 26 varies depending on the composition of the resin is preferably from 80 to 150 ° C., and more preferably 90 to 140 ° C..
Further, in the second region 26, the raw material temperature T ₂ may be a uniform, may be different by site. In the latter case, the minimum temperature of the raw material 5 in the first region 25 is preferably within the above range.
In the illustrated configuration, a temperature transition region 28 in which the raw material temperature transitions from T ₁ to T ₂ is provided between the first region 25 and the second region 26.

  In addition, the residence time of the raw material 5 in the second region 26 is preferably 0.5 to 12 minutes, and more preferably 1 to 7 minutes. If the residence time in the second region 26 is less than the lower limit value, the above-described effect by providing the second region 26 may not be sufficiently obtained. On the other hand, if the residence time in the second region 26 exceeds the upper limit value, the production efficiency is lowered, and depending on the temperature in the process unit 2, the rotational speed of the screw 22, the screw 23, etc., the raw material due to heat 5 may easily occur, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.

Moreover, it is preferable that the length of the 2nd area | region 26 is 20-200 cm, and it is more preferable that it is 40-150 cm. If the length of the second region 26 is less than the lower limit value, the above-described effect by providing the second region 26 may not be sufficiently obtained. On the other hand, when the length of the second region 26 exceeds the upper limit value, the production efficiency is lowered. Depending on the temperature in the process unit 2, the rotational speed of the screw 22, the screw 23, and the like, the raw material 5 due to heat is reduced. This tends to cause modification, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.
Further, the material temperature _{T 1} of the first region 25 within the material temperature _{T 2} within the second region _26, to satisfy the relationship of _{(T 1 -T 2) ≧ 80} [℃] Preferably 80 ≦ (T ₁ −T ₂ ) ≦ 160 is more preferable. When (T ₁ -T ₂ ) is less than the lower limit, it may be difficult to sufficiently prevent phase separation in the cooling step described later.

The number of rotations of the screw 22 and the screw 23 varies depending on the blending ratio of the block polyester and the amorphous polyester, their composition, molecular weight, and the like, but is preferably 50 to 600 rpm. If the number of rotations of the screw 22 and the screw 23 is less than the lower limit value, for example, in the first region 25, it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester. In the second region 26, it may be difficult to sufficiently prevent phase separation. On the other hand, when the rotation speeds of the screw 22 and the screw 23 exceed the upper limit value, the molecules of the polyester may be cut by shearing, and the resin characteristics may be deteriorated.
In the illustrated configuration, a third region 27 different from the first region 25 and the second region 26 is provided on the feeder 4 side of the first region 25 (the side opposite to the second region 26). It has been. As described above, the process unit 2 may have a region other than the first region 25 and the second region 26.

The material temperature T ₃ [° C.] in the third region 27 is (T ₂ −40) ≦ T ₃ ≦ (T ₂ +40) between the material temperature T ₂ in the second region 26 and It is preferable to satisfy the relationship, and it is more preferable to satisfy the relationship of (T ₂ −20) ≦ T ₃ ≦ (T ₂ +20). Material temperature T ₃ is the difficult to be less than the lower limit resin is melted, there is a case where the kneading torque becomes too high. On the other hand, the material temperature T ₃ exceeds the above upper limit value, also the feeder increases the temperature of the raw material inlet is heated, there is a case where the resin is melts secured to the feeder.

In the illustrated configuration, a temperature transition region 29 in which the raw material temperature transitions from T ₃ to T ₁ is provided between the third region 27 and the first region 25.
In the illustrated configuration, the configuration in which the first region 25, the second region 26, and the third region 27 are provided has been described. May be. For example, such a region may be between the first region 25 and the second region 26, or may be closer to the head unit 3 than the second region 26.

[Extrusion process]
The kneaded material 7 kneaded in the process unit 2 is pushed out of the kneader 1 through the head unit 3 by the rotation of the screw 22 and the screw 23.
The head unit 3 has an internal space 31 into which the kneaded product 7 is fed from the process unit 2 and an extrusion port 32 through which the kneaded product 7 is extruded.
The temperature of the kneaded product 7 in the internal space 31 (at least the temperature near the extrusion port 32) T ₄ [° C.] is preferably about 10 ° C. higher than T ₂ . When the temperature T ₄ of the kneaded product 7 is such a temperature, the kneaded product 7 does not solidify in the internal space 31 and is easily extruded from the extrusion port 32.

In the illustrated configuration, the internal space 31 has a cross-sectional area gradually decreasing portion 33 in which the cross-sectional area gradually decreases in the direction of the extrusion port 32.
By having such a cross-sectional area gradually decreasing portion 33, the extrusion amount of the kneaded material 7 extruded from the extrusion port 32 is stabilized, and the cooling rate of the kneaded material 7 in the cooling step described later is stabilized. As a result, the toner produced using the toner has a small variation in characteristics among the toner particles, and has excellent overall characteristics.

[Cooling process]
The softened kneaded product 7 extruded from the extrusion port 32 of the head unit 3 is cooled by the cooler 6 and solidified.
The cooler 6 includes rolls 61, 62, 63, 64 and belts 65, 66.
The belt 65 is wound around a roll 61 and a roll 62. Similarly, the belt 66 is wound around a roll 63 and a roll 64.

  The rolls 61, 62, 63, 64 rotate about the rotation shafts 611, 621, 631, 641 in the directions indicated by e, f, g, h in the figure. Thereby, the kneaded material 7 extruded from the extrusion port 32 of the kneader 1 is introduced between the belt 65 and the belt 66. The kneaded material 7 introduced between the belt 65 and the belt 66 is cooled while being formed into a plate shape having a substantially uniform thickness. The cooled kneaded material 7 is discharged from the discharge part 67. The belts 65 and 66 are cooled by a method such as water cooling or air cooling. When such a belt type is used as the cooler, the contact time between the kneaded product extruded from the kneader and the cooling body (belt) can be increased, and the cooling efficiency of the kneaded product is particularly excellent. Can be.

  By the way, in the kneading step, since the shearing force is applied to the raw material 5, phase separation or the like is sufficiently prevented. However, the kneaded product 7 that has finished the kneading step is not subjected to the shearing force and is left for a long time. Otherwise, phase separation may occur again. Therefore, it is preferable to cool the kneaded product 7 obtained as described above as soon as possible. Specifically, the cooling rate of the kneaded material 7 (for example, the cooling rate when the kneaded material 7 is cooled to about 60 ° C.) is preferably −3 ° C./second or more, and is preferably −5 to −100 ° C. / More preferably it is seconds. In addition, the time required from the end of the kneading step (when the shearing force is no longer applied) to the completion of the cooling step (for example, the time required for cooling the temperature of the kneaded product 7 to 60 ° C. or less) is 20 seconds. Or less, more preferably 3 to 12 seconds.

In the embodiment described above, the configuration using a continuous twin-screw kneading extruder as the kneading machine has been described, but the kneading machine used for kneading the raw materials is not limited to this. For kneading the raw materials, for example, various kneaders such as a kneader, a batch type triaxial roll, a continuous biaxial roll, a wheel mixer, and a blade type mixer can be used.
In the illustrated configuration, the kneader having two screws has been described. However, the number of screws may be one or three or more.

Further, in the present embodiment, the configuration using one kneader has been described, but kneading may be performed using two kneaders. In this case, the process part of one kneader may be used as the first region 25 and the process part of the other kneader may be used as the second region 26.
In the above-described embodiment, the configuration using the belt type as the cooler has been described. However, for example, a roll type (cooling roll type) cooler may be used. Further, the cooling of the kneaded product extruded from the extrusion port 32 of the kneader is not limited to the one using the above-described cooler, and may be performed by, for example, air cooling.

[Granulation process]
By granulating the kneaded material 7 that has undergone the cooling process as described above, a powder for toner production is obtained.
In the present embodiment, the granulation step includes a pulverization step as described below, and performs a thermal spheronization treatment as necessary.
Note that the thermal spheronization step is not necessarily performed.

<Crushing process>
First, the kneaded material 7 that has undergone the cooling process as described above is pulverized.
The pulverization method is not particularly limited, and for example, it can be performed using various pulverizers such as a ball mill, a vibration mill, a jet mill, and a pin mill, and a crusher.
The pulverization process may be performed in multiple steps (for example, two stages of a coarse pulverization process and a fine pulverization process).

In addition, after such a pulverization step, a classification process or the like may be performed as necessary.
For the classification treatment, for example, a sieve, an airflow classifier or the like can be used.
In addition, when a thermal spheronization treatment as will be described later is performed, the obtained powder for toner production may be subjected to an external addition treatment for adding an external additive as a pretreatment in the thermal spheronization step. By performing such an external treatment as a pretreatment, the fluidity and dispersibility of the toner particles are improved, and it is possible to sufficiently prevent and suppress fusion between the toners due to heat. In addition, the external addition process as such a pretreatment can be performed in the same manner as the external addition process as a subsequent process of the thermal spheronization process as described later, and an external additive described in detail later is used. Can be used.

<Thermal spheronization process (thermal spheronization process)>
Next, if necessary, a heat spheronization treatment may be performed in which the powder (powder for toner production) obtained in the pulverization step is heated to be spheroidized.
By performing such a thermal spheronization treatment, relatively large irregularities on the surface of the powder for toner production are removed, and the circularity becomes relatively high. As a result, the finally obtained toner has a small difference in charging characteristics between the individual toner powders, and the developability on the photoconductor is improved and the toner adheres to the photoconductor (filming). ) Is more effectively prevented, and the toner transfer efficiency is further improved.

  In particular, since the present invention includes a block polyester having a crystalline block, when the thermal spheronization treatment is performed, the amorphous polyester is sufficiently softened while ensuring the stability of the shape of the powder for toner production to some extent. Can do. Therefore, in the present invention, compared with the case where a raw material not containing block polyester is used, the thermal spheronization treatment can be efficiently performed, and the degree of circularity of the finally obtained toner (toner particles) can be relatively easily achieved. Can be relatively high. Moreover, as a result, the effect by the thermal spheroidization process mentioned above can be exhibited more effectively.

  The thermal spheronization treatment can be performed by injecting the powder for toner production obtained in the pulverization step into a heated atmosphere using, for example, compressed air. At this time, the atmospheric temperature is preferably 210 to 320 ° C, and more preferably 230 to 300 ° C. If the atmospheric temperature is less than the lower limit, it may be difficult to sufficiently increase the circularity. On the other hand, when the ambient temperature exceeds the upper limit, the material is likely to be thermally decomposed, oxidized and deteriorated, and aggregation, phase separation and the like are likely to occur, and the function of the finally obtained toner may be lowered.

Further, when the thermal spheronization treatment is performed, when the melting point of the block polyester is T _m (B) [° C.] and the softening point of the amorphous polyester is T _1/2 (A) [° C.], the thermal spheronization step It is preferable that the atmospheric temperature T _S [° C.] satisfies the relationship of (T _1/2 (A) +120) ≦ T _S ≦ (T _m (B) +90), and (T _1/2 (A) More preferably, the relationship of +140) ≦ T _S ≦ (T _m (B) +70) is satisfied. By performing the thermal spheronization treatment at such an ambient temperature T _s , the degree of circularity of the toner particles obtained can be sufficiently prevented while the occurrence of thermal decomposition, oxidation degradation, etc., aggregation, phase separation, etc. of the material is sufficiently prevented. Can be made relatively high.

Moreover, you may perform such a thermal spheronization process in a liquid.
Further, after such a thermal spheronization step, a treatment such as a classification treatment may be performed as necessary.
For the classification treatment, for example, a sieve, an airflow classifier or the like can be used.
Further, such a thermal spheronization treatment may be omitted if it is not particularly necessary. If not, the external powder as described later is added to the obtained powder for toner production after the pulverization step. Processing may be performed.

[External addition process (external addition process)]
Next, an external additive is added to the obtained powder for toner production.
Examples of the external additive include titanium oxide, silica (positively charged silica, negatively charged silica, etc.), aluminum oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, zinc oxide, alumina, magnetite, and the like. Fine particles composed of inorganic materials such as oxides, nitrides such as silicon nitride, carbides such as silicon carbide, metal salts such as calcium sulfate, calcium carbonate, and aliphatic metal salts, acrylic resins, fluororesins, polystyrene resins, polyesters Examples thereof include resins and organic metal materials such as aliphatic metal salts (for example, magnesium stearate).

Among the external additives, examples of the titanium oxide that can be used as the external additive include rutile type titanium oxide, anatase type titanium oxide, and rutile anatase type titanium oxide.
The rutile anatase type titanium oxide has a rutile type titanium oxide (titanium dioxide) and a crystal structure anatase type titanium oxide (titanium dioxide) in the same particle. That is, the rutile anatase type titanium oxide has a mixed crystal type titanium oxide (titanium dioxide) of a rutile type crystal and an anatase type crystal.

Rutile-type titanium oxide usually has the property of easily forming spindle-shaped crystals. In addition, anatase type titanium oxide has the property of easily depositing fine crystals and being excellent in affinity with a silane coupling agent or the like used for hydrophobizing treatment or the like.
And since rutile anatase type titanium oxide has a mixed crystal type titanium oxide of a rutile type crystal and an anatase type crystal, the advantage of the rutile type titanium oxide and the advantage of the anatase type titanium oxide And have both. That is, in the rutile-anatase type titanium oxide, a minute anatase-type crystal is mixed between the rutile-type crystals (inside the rutile-type crystal), and as a whole has a substantially spindle shape, It becomes difficult to embed in the mother particles, and the rutile-anatase-type titanium oxide as a whole has excellent affinity with silane coupling agents, etc., so that it is uniform on the surface of the rutile-anatase-type titanium oxide powder. A stable hydrophobic coating (silane coupling coating) is easily formed. Therefore, the toner obtained by containing the rutile-anatase type titanium oxide has a uniform charge distribution (the charge distribution of the toner particles is sharp), a stable charge characteristic, environmental characteristics (especially moisture resistance), and fluidity. And excellent caking resistance.

In particular, the rutile-anatase type titanium oxide exhibits the following synergistic effect when used in combination with the polyester resin as described above.
That is, as described above, in the present invention, the polyester-based resin contains a block polyester having a crystalline block with high crystallinity. Therefore, in the toner particles, the polyester resin has a predetermined size mainly formed by the crystalline block. It can have a crystal. By having such a crystal, the rutile-anatase type titanium oxide becomes difficult to be embedded in the toner base particles. That is, by including a hard component such as the crystal, the rutile-anatase type titanium oxide is surely supported (attached) near the surface of the toner base particles. Thereby, the function of rutile-anatase-type titanium oxide (particularly, effects such as excellent fluidity and chargeability) can be sufficiently exhibited. Thus, since the function of a rutile-anatase type titanium oxide can fully be exhibited by using together with the polyester-type resin mentioned above, the quantity of the external additive to be used can be suppressed. As a result, it is possible to effectively prevent the occurrence of inconvenience (for example, a decrease in fixability to a transfer material (recording medium) such as paper) due to the addition of a large amount of external additive.

The ratio of the rutile-type titanium oxide to the anatase-type titanium oxide in the rutile-anatase-type titanium oxide is not particularly limited, but is preferably 5:95 to 95: 5 by weight, and 50:50 More preferably, it is -90: 10. By using such a rutile-anatase type titanium oxide, the effect by using the above-mentioned rutile-anatase type titanium oxide becomes more remarkable.
The rutile-anatase type titanium oxide preferably absorbs light in the wavelength region of 300 to 350 nm. As a result, the toner has excellent light resistance (particularly, light resistance after fixing on a recording medium).

The shape of the rutile-anatase type titanium oxide used in the present invention is not particularly limited, but it is generally a spindle shape.
When the rutile-anatase type titanium oxide has a substantially spindle shape, the average major axis diameter is preferably 10 to 100 nm, and more preferably 20 to 50 nm. When the average major axis diameter is in such a range, the rutile-anatase type titanium oxide can sufficiently exhibit the functions described above, and is difficult to be embedded in the toner base particles. It becomes difficult to release. As a result, the stability of the toner against mechanical stress is further improved.

  The content of the rutile-anatase type titanium oxide in the toner is not particularly limited, but is preferably 0.1 to 2.0 wt%, and more preferably 0.5 to 1.0 wt%. If the content of the rutile-anatase type titanium oxide is less than the lower limit, the effect of using the rutile-anatase type titanium oxide as described above may not be sufficiently exhibited. On the other hand, when the content of the rutile-anatase type titanium oxide exceeds the upper limit, the toner fixing property tends to be lowered.

  Such a rutile-anatase type titanium oxide may be prepared by any method, but can be obtained, for example, by firing anatase-type titanium oxide. By using such a method, the abundance ratio of the rutile-type titanium oxide and the anatase-type titanium oxide in the rutile-anatase-type titanium oxide can be controlled relatively easily and reliably. When obtaining a rutile-anatase type titanium oxide by such a method, it is preferable that a calcination temperature is about 700-1000 degreeC. By setting the firing temperature within this range, it is possible to more easily and reliably control the abundance ratio of rutile titanium oxide and anatase titanium oxide in rutile anatase titanium oxide. Become.

  Moreover, it is preferable that the rutile-anatase type titanium oxide is hydrophobized. By applying the hydrophobizing treatment, the effect that charging is not greatly influenced by humidity can be obtained. As the hydrophobizing treatment, for example, HMDS, a silane coupling agent (for example, one having a functional group such as an amino group), a titanate coupling agent, a fluorine-containing silane coupling agent, silicone oil or the like is used. And surface treatment of rutile-anatase type titanium oxide powder (particles).

Among the external additives described above, examples of silica that can be used as the external additive include positively charged silica and negatively charged silica. The positively chargeable silica can be obtained, for example, by subjecting negatively chargeable silica to a surface treatment with a silane coupling agent having a functional group such as an amino group.
When negatively chargeable silica is used as an external additive, the charge amount (absolute value) of the toner particles can be increased. As a result, a stable negatively chargeable toner can be obtained, and the toner control of the image forming apparatus can be easily performed.

  Further, when negatively charged silica is used in combination with the rutile-anatase type titanium oxide described above, a particularly excellent effect is obtained. That is, by using negatively-charged silica and rutile-anatase type titanium oxide in combination, the fluidity and environmental characteristics (especially moisture resistance) of the toner can be further improved, and more stable triboelectric chargeability can be exhibited. Thus, the occurrence of so-called fog can be more effectively prevented. Further, by using negatively-charged silica and rutile-anatase type titanium oxide in combination, the obtained toner can have a large charge amount (absolute value) and a sharper charge distribution.

When the average major axis diameter of the substantially spindle-shaped rutile-anatase type titanium oxide is D ₁ [nm] and the average particle diameter of the negatively charged silica is D ₂ [nm], 0.2 ≦ D ₁ / D ₂ ≦ It is preferable that the relationship of 15 is satisfied, and it is more preferable that the relationship of 0.4 ≦ D ₁ / D ₂ ≦ 5 is satisfied. By satisfying such a relationship, the effect of using negatively charged silica and rutile-anatase type titanium oxide in combination becomes even more remarkable. In the present specification, “average particle diameter” refers to an average particle diameter based on volume.

  Further, when positively chargeable silica is used as the external additive, for example, the positively chargeable silica can function as a microcarrier, and the chargeability of the toner particles themselves can be further improved. In particular, by using the positively chargeable silica in combination with the above-described rutile-anatase type titanium oxide, the obtained toner can have a large charge amount (absolute value) and a sharper charge distribution. .

When positively chargeable silica is included, the average particle size is preferably 30 to 100 nm, and more preferably 40 to 50 nm. When the average particle diameter of the positively chargeable silica is in such a range, the above-described effect becomes more remarkable.
Further, as the external additive, HMDS, a silane coupling agent (for example, one having a functional group such as an amino group), titanate coupling agent on the surface of the fine particles composed of the materials as described above. Alternatively, a surface treated with a fluorine-containing silane coupling agent, silicone oil or the like may be used.

Such an external additive can be added, for example, by mixing with a powder for toner production using a Henschel mixer or the like.
In addition, the toner powder obtained in this way has a coating ratio of the external additive (the ratio of the area covered by the external additive to the surface area of the toner particles, and spheres corresponding to the average particle diameter of the external additive are The calculated coverage when a sphere having a diameter corresponding to 6-way fine packing is preferably 100 to 300%, and more preferably 120 to 220%. If the coverage of the external additive is less than the lower limit, the effect of the external additive as described above may not be sufficiently exhibited. On the other hand, when the coverage of the external additive exceeds the upper limit, the toner fixability tends to decrease.

Further, the external additive may be in a state where substantially all of the external additive is attached to the toner particles (mother particles) in the toner, or a part of the external additive may be released from the surface of the toner particles. Good. That is, the toner may contain an external additive released from the toner particles.
Thus, when the toner contains an external additive released from the mother particles (hereinafter also referred to as “free external additive”), such a free external additive is, for example, opposite to the toner particles. It can function as a microcarrier that is charged to polarity. When such a free external additive functioning as a microcarrier is included in the toner, toner particles having a reverse chargeability during development or the like (toner particles that are charged with a polarity opposite to the polarity that the toner particles should originally exhibit when charged) ) Can be effectively prevented and suppressed. As a result, the toner is less likely to cause inconveniences such as so-called fog.

  The amount of the external additive released from the toner particles is, for example, the annual meeting of the Electrophotographic Society (95 times in total) "Japan Hardcopy'97" paper collection, "New External Evaluation Method-Toner Analysis Using Particle Analyzer" (Suzuki) Measurement is possible by applying the method disclosed in Toshiyuki, Toshio Takahara, sponsored by the Electrophotographic Society, July 9-11, 1997). Hereinafter, an example of a method for measuring the amount of free external additive by a particle analyzer (PT1000) in the case of using (rutile-anatase type) titanium oxide as an external additive will be described.

In this measuring method, toner particles are formed by introducing toner T particles formed by attaching an external additive made of titanium oxide (TiO ₂ ) to the surface of base particles made of resin (C). This is a method of measuring by performing excitation, obtaining an emission spectrum accompanying this excitation, and performing elemental analysis.
First, when toner particles in which an external additive (TiO ₂ ) adheres to toner manufacturing powder (mother powder) are introduced into the plasma, both the mother particles (C) and the external additive (TiO ₂ ) emit light. At this time, since the mother particles (C) and the external additive (TiO ₂ ) are simultaneously introduced into the plasma, the mother particles (C) and the external additive (TiO ₂ ) emit light simultaneously. Thus, when the mother particles (C) and the external additive (TiO ₂ ) emit light simultaneously, the mother particles (C) and the external additive (TiO ₂ ) are said to be synchronized. In other words, the state in which the base particle (C) and the external additive (TiO ₂ ) are synchronized represents the state in which the external additive (TiO ₂ ) is attached to the base particle (C).

Also, if the external additive (TiO ₂₎ is liberated external additive from the mother particles not attached (C) or base particle (C) (TiO ₂₎ is introduced into the plasma, similar to the above mother particles Both (C) and the external additive (TiO ₂ ) emit light, but at this time, since the base particles (C) and the external additive (TiO ₂ ) are introduced into the plasma at different times, the base particles ( C) and the external additive (TiO ₂ ) emit light at different times (for example, when the mother particle is introduced into the plasma before the external additive, the mother particle emits light first, and then delays) The external additive emits light).
Thus, when the mother particles (C) and the external additive (TiO ₂ ) emit light at different times, the mother particles (C) and the external additive (TiO ₂ ) are not synchronized ( That is, it is asynchronous). In other words, the state in which the base particle (C) and the external additive (TiO ₂ ) are asynchronous represents a state in which the external additive (TiO ₂ ) is not attached to the base particle (C).

Further, in the emission spectrum obtained as described above, the height of the emission signal indicates the intensity of the emission, but this emission intensity is not included in the size or shape of the particles but is included in the particles. It is proportional to the number of atoms of the element (C, TiO ₂ ). Therefore, in order to express the light emission intensity of the element as the particle size, when the light emission of the base particle (C) and the external additive (TiO ₂ ) is obtained, the base particle (C) and the external additive (TiO ₂ ) are obtained. ₂ ) Assuming true spherical particles made only of these, the true spherical particles at this time are called equivalent particles, and these particle sizes are called equivalent particle sizes. Since the external additive is very small, it is impossible to detect each of these particles one by one. Therefore, the detected emission signals of the external additive are added together and converted into one equivalent particle for analysis.
When the equivalent particle diameters of the equivalent particles obtained from the emission spectra of the mother particles and the external additives are plotted for each toner particle, an equivalent particle size distribution diagram of the toner particles as shown in FIG. 4 is obtained. It is done.

In FIG. 4, the horizontal axis represents the equivalent particle diameter of the base particle (C), and the vertical axis represents the equivalent particle diameter of the external additive (TiO ₂ ). The equivalent particles on the horizontal axis represent asynchronous mother particles (C) to which no external additive (TiO ₂ ) is attached, and the equivalent particles on the vertical axis are free from the mother particles (C). Asynchronous external additive (TiO ₂ ). Equivalent particles not on the horizontal and vertical axes represent synchronous toner in which an external additive (TiO ₂ ) is attached to the base particles (C). In this way, the adhesion state of the external additive (TiO ₂ ) to the toner base particles (C) is analyzed.

  The amount of rutile-anatase-type titanium oxide released from the toner particles that can be measured in this way (ratio of rutile-anatase-type titanium oxide contained in the toner as a free external additive) is 0.1 to 5.0 wt% is preferable, and 0.5 to 3.0 wt% is more preferable. If the ratio of the free external additive is too small, the above-mentioned function as a microcarrier may not be sufficiently exhibited. On the other hand, when the ratio of the free external additive exceeds the upper limit, the free external additive adheres to the toner contact member and filming is likely to occur.

The toner (toner powder) obtained as described above preferably has an average circularity R represented by the following formula (I) of 0.90 to 0.98, and 0.92 to 0.98. Is more preferable. If the average circularity R is less than 0.90, it becomes difficult to sufficiently reduce the difference in charging characteristics between individual toner powders, and the developability on the photoreceptor tends to be lowered. On the other hand, if the average circularity R is too small, toner adhesion (filming) is likely to occur on the photoreceptor, and the toner transfer efficiency may be reduced. On the other hand, when the average circularity R exceeds 0.98, the transfer efficiency and mechanical strength are increased, but there is a problem that the average particle diameter is increased by promoting granulation (joining of particles). If the average circularity R exceeds 0.98, for example, it becomes difficult to remove the toner adhering to the photoreceptor or the like by cleaning.
R = L ₀ / L ₁ (I)
(Where, L ₁ [μm] is the circumference of the projected image of the toner particles to be measured, and L ₀ [μm] is a perfect circle having an area equal to the area of the projected image of the toner particles to be measured (completely (Represents the perimeter of a geometric circle)

The average particle diameter of the toner is preferably 3 to 12 μm, and more preferably 5 to 10 μm. When the average particle diameter of the toner is less than the lower limit, fusion between the toner particles is likely to occur. On the other hand, when the average particle diameter of the toner exceeds the upper limit, the resolution of the printed matter tends to decrease.
Further, the content of the polyester resin in the toner is preferably 50 to 98 wt%, and more preferably 85 to 97 wt%. If the content of the polyester resin is less than the lower limit, the effect of the present invention may not be sufficiently obtained. On the other hand, when the content of the polyester-based resin exceeds the upper limit, the content of components such as a colorant may be relatively lowered, and it may be difficult to exhibit characteristics such as color developability.

  In addition, the composition of the block polyester contained in the toner (constituent monomer, abundance ratio of the crystalline block, etc.), the average weight molecular weight Mw, the glass transition point, the softening point, the melting point, etc. The average weight molecular weight Mw, glass transition point, softening point, and the like are preferably the same as those described in the item of the constituent material of the raw material 5, but may be changed during the manufacturing process.

When the toner contains wax, the content is not particularly limited, but is preferably 5 wt% or less, more preferably 3 wt% or less, and 0.5 to 3 wt%. Further preferred. If the content of the wax is too large, the wax is liberated and coarsened, and the exudation of the wax on the toner surface may occur remarkably, making it difficult to sufficiently increase the toner transfer efficiency.
The acid value as a physical property of the toner is one of the factors that influence the environmental characteristics (particularly moisture resistance) of the toner. The acid value of the toner is preferably 8 KOH mg / g or less, and more preferably 1 KOH mg / g or less. When the acid value of the toner is 8 KOHmg / g or less, the environmental characteristics (particularly moisture resistance) of the toner are particularly excellent.

  Further, when the toner applied to the present invention is used in a fixing device having a nip portion as will be described later, the change in relaxation elastic modulus G (t) in the passage time Δt [second] of the toner particles through the nip portion. The amount is preferably 500 [Pa] or less, and more preferably 100 [Pa] or less. Satisfying such conditions makes it more difficult to cause inconveniences such as offset.

  In addition, the toner applied to the present invention, when used in a fixing device having a fixing nip portion as described later, represents a time required for the toner particles to pass through the fixing nip portion by Δt [seconds]. When the relaxation elastic modulus at 0.01 seconds is the initial relaxation elastic modulus G (0.01) and the relaxation elastic modulus at Δt seconds of the toner is G (Δt), G (0.01) / G ( It is preferable to satisfy the relationship of Δt) ≦ 10, and it is more preferable to satisfy the relationship of 1 ≦ G (0.01) / G (Δt) ≦ 8. 1 ≦ G (0.01) / G (Δt ) ≦ 6 is more preferably satisfied. Satisfying such a relationship makes it difficult for toner to cry and offset due to a decrease in the elastic modulus of the toner particles. On the other hand, if G (0.01) / G (Δt) exceeds 10, the toners are separated and the offset is likely to occur. The relaxation elastic modulus of the toner is, for example, the composition of the constituent material of the toner (for example, the molecular weight of the block polyester and the amorphous polyester, the monomer component, the randomness, the composition of the wax and the external additive, the content of each constituent component, etc. And the production conditions of the toner (for example, the raw material temperature in the kneading step, the kneading time, the cooling rate of the kneaded product in the cooling step, the processing temperature in the thermal spheronization step, etc.).

Further, in the toner applied to the present invention, there are usually crystals mainly composed of crystalline blocks of block polyester.
Such crystals preferably have an average length (average length in the longitudinal direction) of 10 to 1000 nm, and more preferably 50 to 700 nm. When the length of the crystal is in such a range, the toner shape stability is particularly excellent, and particularly excellent stability against mechanical stress is exhibited. In particular, the external additive is more reliably held near the surface of the toner particles (the external additive can be effectively prevented from being buried in the mother particles). In particular, the stability of the film is excellent, and the occurrence of filming or the like hardly occurs. The crystal size can be changed, for example, by changing the molecular weight and randomness of the block polyester by controlling the production conditions of the block polyester used as a raw material component, or the blending ratio of the block polyester and the amorphous polyester. It can be appropriately adjusted by changing or changing the conditions of the kneading step and the cooling step described above.

In particular, when the toner contains rutile-anatase type titanium oxide, it is preferable to satisfy the following relationship. That is, when the average major axis diameter of the substantially spindle-shaped rutile-anatase type titanium oxide is D ₁ [nm] and the average crystal length is L _C [nm], 0.01 ≦ D ₁ / L _C ≦ 2 It is preferable to satisfy this relationship, and it is more preferable to satisfy the relationship of 0.02 ≦ D ₁ / L _C ≦ 1. By satisfying such a relationship, the rutile-anatase type titanium oxide exhibits the above-described effects sufficiently and is difficult to be embedded in the mother particles. As a result, the toner sufficiently retains the above-described functions and is particularly excellent in stability against mechanical stress.
The average length of the crystal can be measured by a transmission electron microscope (TEM), small angle X-ray scattering measurement, or the like.

Further, the toner applied to the present invention is preferably one in which block polyester and amorphous polyester are compatible as much as possible. As a result, variations in characteristics among the toner particles are small, the characteristics of the toner as a whole are more stable, and the effects of the present invention become more remarkable.
The toner applied to the present invention is preferably applied to a non-magnetic one-component toner. Non-magnetic one-component toner is generally applied to an image forming apparatus having a regulating blade as described later. Therefore, the toner applied to the present invention that is resistant to mechanical stress can exhibit the above-described effects more remarkably when used as a non-magnetic one-component toner.

  The fixing device using the toner applied to the present invention is not particularly limited, but is preferably used for a contact-type fixing device as described later. As a result, both the advantages of high releasability from the fixing roller due to the block polyester crystals and the effect of improving the fixability (fixing strength) due to the low-viscosity amorphous polyester are fully exhibited, and a wide range of good fixing is obtained. Secured.

Next, a fixing device and an image forming apparatus applied to the image forming method of the present invention will be described.
FIG. 5 is an overall configuration diagram showing a preferred embodiment of an image forming apparatus applied to the image forming method of the present invention, FIG. 6 is a sectional view of a developing device included in the image forming apparatus of FIG. 5, and FIG. 5 shows a detailed structure of the fixing device used in the image forming apparatus of FIG. 5, a perspective view showing a partially broken section, FIG. 8 is a sectional view of a principal part of the fixing device of FIG. 7, and FIG. 9 is a fixing device of FIG. FIG. 10 is a side view showing a mounting state of the peeling member constituting the fixing device of FIG. 7, FIG. 11 is a front view of the fixing device of FIG. FIG. 13 is a schematic diagram for explaining the arrangement angle of the peeling member with respect to the tangent at the outlet of the nip portion, FIG. 13 is a diagram schematically showing the shape of the fixing roller and the pressure roller, and the shape of the nip portion. Is a cross-sectional view taken along line XX of FIG. 13A, and FIG. 15 is a fixing roller and a pressure roller. FIG. 16 is a cross-sectional view taken along line YY of FIG. 15A, and FIG. 17 is a diagram for explaining a gap between the fixing roller and the peeling member. It is sectional drawing.

  An image carrier 30 including a photosensitive drum is disposed in the apparatus main body 20 of the image forming apparatus 10 and is rotationally driven in a direction indicated by an arrow by a driving unit (not shown). Around the image carrier 30, an electrostatic latent image is formed on the image carrier 30, a charging device 40 for uniformly charging the image carrier (photoconductor) 30 along the rotation direction. There are provided an exposure device 50, a rotary developing device 60 for developing an electrostatic latent image, and an intermediate transfer device 70 for primary transfer of a monochromatic toner image formed on the image carrier 30.

In the rotary developing device 60, a yellow developing device 60Y, a magenta developing device 60M, a cyan developing device 60C, and a black developing device 60K are mounted on a support frame 600, and the support frame 600 is driven to rotate by a motor (not shown). It is the composition which becomes. The plurality of developing devices 60Y, 60C, 60M, and 60K are selectively rotated so that the developing roller 604 of one developing device faces the image carrier 30 every rotation of the image carrier 30. Has been. Each of the developing devices 60Y, 60C, 60M, and 60K has a toner storage portion that stores toner of each color.
The developing devices 60Y, 60C, 60M, and 60K all have the same structure. Therefore, although the structure of the developing device 60Y will be described here, the structures and functions of the developing devices 60C, 60M, and 60K are the same.

  As shown in FIG. 6, in the developing device 60Y, a supply roller 603 and a developing roller 604 are axially attached to a housing 601 that accommodates toner T therein, and when the developing device 60Y is positioned at the development position described above. The developing roller 604 functioning as a “toner carrier” is positioned in contact with the image carrier (photoreceptor) 30 or with a predetermined gap therebetween, and these rollers 603 and 604 are provided on the main body side. It is configured to be engaged with a rotation drive unit (not shown) and to rotate in a predetermined direction. The developing roller 604 is formed in a cylindrical shape from a metal or alloy such as copper, stainless steel, or aluminum so that a developing bias is applied.

  In the developing device 60Y, a regulating blade 605 for regulating the thickness of the toner layer formed on the surface of the developing roller 604 to a predetermined thickness is disposed. The regulating blade 605 is composed of a plate-like member 605a such as stainless steel or phosphor bronze, and an elastic member 605b such as rubber or resin member attached to the tip of the plate-like member 605a. The rear end portion of the plate-like member 605a is fixed to the housing 601, and the elastic member 605b attached to the front end portion of the plate-like member 605a is the rear end portion of the plate-like member 605a in the rotation direction D3 of the developing roller 604. It arrange | positions so that it may be located in the upstream rather than.

The intermediate transfer device 70 includes a driving roller 90 and a driven roller 100, an intermediate transfer belt 110 that is driven by the two rollers in the direction indicated by the arrow, and a primary transfer that is disposed on the back surface of the belt 110 so as to face the image carrier 30. A roller 120, a transfer belt cleaner 130 for removing residual toner on the belt 110, and a drive roller 90 are arranged to face the four-color full-color image formed on the intermediate transfer belt 110 on a recording medium (paper or the like). And a secondary transfer roller 140 for transferring the toner to the ink.
A paper feed cassette 150 is disposed at the bottom of the apparatus main body 20, and a recording medium in the paper feed cassette 150 passes through a pickup roller 160, a recording medium conveyance path 170, a secondary transfer roller 140, and a fixing device 190, and a paper discharge tray. It is comprised so that it may be conveyed by 200. Reference numeral 230 denotes a duplex printing conveyance path.

  The operation of the image forming apparatus having the above configuration will be described. When an image forming signal from a computer (not shown) is input, the image carrier 30, the developing roller 604 of the rotary developing device 60 and the intermediate transfer belt 110 are rotationally driven. First, the outer peripheral surface of the image carrier 30 is charged by the charging device 40. The exposure apparatus 50 selectively exposes the outer peripheral surface of the uniformly charged image carrier 30 according to the image information of the first color (for example, yellow), and the electrostatic charge of yellow A latent image is formed.

  On the other hand, in the developing device 60Y, the two rollers 603 and 604 rotate while being in contact with each other, whereby yellow toner is rubbed against the surface of the developing roller 604, and a toner layer having a predetermined thickness is formed on the surface of the developing roller 604. . Then, the elastic member 605b of the regulating blade 605 elastically contacts the surface of the developing roller 604, and the toner layer on the surface of the developing roller 604 is regulated to a predetermined thickness.

  At the position of the latent image formed on the image carrier 30, the yellow developing device 60 </ b> Y rotates and the developing roller 604 comes into contact therewith, whereby the yellow electrostatic latent image toner image is transferred onto the image carrier 30. Next, the toner image formed on the image carrier 30 is transferred onto the intermediate transfer belt 110 by the primary transfer roller 120. At this time, the secondary transfer roller 140 is separated from the intermediate transfer belt 110.

  The above processing is repeated for the second, third, and fourth colors of the image formation signal, and the latent image formation, development, and transfer are repeated by one rotation of the image carrier 30 and the intermediate transfer belt 110. Four color toner images corresponding to the contents of the image are superimposed and transferred on the intermediate transfer belt 110. Then, at the timing when the full-color image reaches the secondary transfer roller 140, the recording medium is supplied from the conveyance path 170 to the secondary transfer roller 140. At this time, the secondary transfer roller 140 is pressed against the intermediate transfer belt 110. A secondary transfer voltage is applied, and the full-color toner image on the intermediate transfer belt 110 is transferred onto the recording medium. The toner image transferred onto the recording medium is fixed by being heated and pressed by the fixing device 190. The toner remaining on the intermediate transfer belt 110 is removed by the transfer belt cleaner 130.

In the case of double-sided printing, the recording medium exiting the fixing device 190 is switched back so that its trailing edge is the leading edge, supplied to the secondary transfer roller 140 via the double-sided printing conveyance path 230, and intermediate The full color toner image on the transfer belt 110 is transferred onto the recording medium, and is again heated and pressed by the fixing device 190 to be fixed.
In FIG. 5, a fixing device 190 according to the present invention includes a fixing roller 210 having a heat source and a pressure roller 220 pressed against the fixing roller 210. The shaft of the fixing roller 210 and the pressure roller 220 is connected to a horizontal line. It arrange | positions so that it may have the angle of (theta). Note that 0 ° ≦ θ ≦ 30 °.

Next, the fixing device 190 will be described in detail.
7 and 11, a fixing roller 210 is rotatably mounted in a housing 240, and a driving gear 28 is connected to one end of the fixing roller 210. A pressure roller 220 is rotatably mounted facing the fixing roller 210. The axial length of the pressure roller 220 is shorter than that of the fixing roller 210, and a bearing 250 is provided in the vacant space, and both ends of the pressure roller 220 are supported by the bearing 250. A pressure lever 260 is rotatably provided on the bearing 250, and a pressure spring 270 is disposed between one end of the pressure lever 260 and the housing 240, whereby the pressure roller 220 and the fixing roller 210 are pressurized. It is configured to be.

  In FIG. 8, a fixing roller 210 includes a metal cylinder 210b having a heat source 210a such as a halogen lamp inside, an elastic layer 210c made of silicon rubber or the like provided on the outer periphery of the cylinder 210b, and the surface of the elastic layer 210c. A surface layer (not shown) made of fluororubber and fluororesin (for example, pertetrafluoroethylene (PTFE)) covered with a rotating shaft 210d fixed to the cylinder 210b.

  The pressure roller 220 is formed on the outer periphery of the cylindrical body 220b in the same manner as the metal cylindrical body 220b, the rotating shaft 220d fixed to the cylindrical body 220b, the bearing 250 supporting the rotating shaft 220d, and the fixing roller 210. The elastic layer 220c is provided, and a surface layer (not shown) made of fluororubber or fluororesin coated on the surface of the elastic layer 220c. The thickness of the elastic layer 210c of the fixing roller 210 is extremely smaller than the thickness of the elastic layer 220c of the pressure roller 220, thereby forming a fixing nip portion 340 in which the pressure roller 220 side is recessed in a concave shape.

  As shown in FIGS. 7 and 8, support shafts 290 and 300 are provided on both side surfaces of the housing 240. The support shafts 290 and 300 are respectively provided with the peeling member 310 and the pressure roller 220 on the fixing roller 210 side. The side peeling member 320 is rotatably mounted. Accordingly, the peeling members 310 and 320 are disposed on the downstream side of the fixing nip portion 340 in the recording medium conveyance direction in the axial direction of the fixing roller 210 and the pressure roller 220.

  As shown in FIGS. 9 and 10, the peeling member 310 on the fixing roller 210 side uses a resin sheet or a metal sheet as a base material, and forms a fluororesin layer on the surface of the base material. The peeling member 310 includes a plate-like peeling portion (base material) 310a, a bent portion 310b bent in an L shape toward the fixing roller 210 at the rear of the peeling portion 310a, and lower portions at both ends of the peeling portion 310a. The support piece 310c is bent in the direction, the fitting hole 310d is formed in the support piece 310c, and the guide part 310e is extended to the front of both side ends of the peeling part 310a.

  The peeling portion 310 a is disposed so as to be inclined toward the outlet (nip outlet 341) of the fixing nip portion 340, and the leading end of the peeling portion 310 a is not in contact with and close to the fixing roller 210. The support shaft 290 described in FIG. 8 is fitted in the fitting hole 310d of the support piece 310c. The guide portion 310e is urged against the housing 240 by the spring 330, whereby the front end of the guide portion 310e is in contact with the fixing roller 210, and as a result, between the front end of the peeling portion 310a and the surface of the fixing roller 210. The gap is always constant.

  The peeling member 320 on the pressure roller 220 side has the same shape as the peeling member on the fixing roller 210 side. However, as shown in FIGS. 7 and 8, the tip of the peeling portion 320a is recorded more than the tip of the peeling portion 310a. It is arranged on the downstream side in the medium conveyance direction. The tip of the guide part 320e is in contact with the peripheral surface of the bearing 250 of the pressure roller 220 at the point P, so that the gap between the tip of the peeling part 320a and the surface of the pressure roller 220 is always constant. To be.

  In the present embodiment, as shown in FIGS. 7 and 8, peeling members 310 and 320 are disposed on the downstream side of the nip portion 340 in the recording medium conveyance direction in the axial direction of the fixing roller 210 and the pressure roller 220. The tip of the peeling member 310 on the fixing roller 210 side is disposed so as to incline toward the exit of the nip portion 340, and is not in contact with and close to the fixing roller 210. The leading end of the peeling member 320 on the pressure roller 220 side is disposed downstream of the leading end of the peeling member 310 on the fixing roller 210 side in the recording medium conveyance direction.

As shown in FIG. 10, the guide member 310 e of the peeling member 310 on the fixing roller 210 side is urged against the housing 240 by the spring 330, so that the tip of the guide portion 310 e is in contact with the fixing roller 210. As a result, the positioning is performed so that the gap between the tip of the peeling portion 310a and the surface of the fixing roller 210 is always constant.
The peeling member 320 on the pressure roller 220 side has the same shape as the peeling member on the fixing roller 210 side, and as shown in FIGS. 7 and 8, the tip of the peeling portion 320a is a recording medium more than the tip of the peeling portion 310a. The tip of the guide part 320e is disposed at the downstream side in the conveying direction, and is in contact with the surface of the bearing 250 of the pressure roller 220 at the point P, whereby the tip of the peeling part 320a and the surface of the pressure roller 220 are in contact with each other. Positioning is performed so that the gap between them is always constant. Therefore, as shown in FIG. 11, the axial length of the pressure roller 220 is shorter than that of the fixing roller 210, and a bearing 250 is provided in the vacant space. It is supported.

  In the case of double-sided printing, the recording medium printed on one side is peeled off by the peeling member 310 on the fixing roller 210 side, and then switched back so that the trailing edge of the recording medium becomes the leading edge, and then passes through the double-sided printing conveyance path 230. The full-color toner image on the intermediate transfer belt 110 is supplied to the secondary transfer roller 140 and is transferred onto the recording medium, and is heated and pressed again by the fixing roller 210. At this time, it adheres to the pressure roller 220 and wraps around. The recording medium is peeled off by the peeling member 320 on the pressure roller 220 side.

  As described above, in the fixing device according to the present embodiment, the peeling is provided in the vicinity of the fixing roller and the pressure roller in the axial direction of the fixing roller and the pressure roller and on the downstream side of the fixing nip portion in the recording medium conveyance direction. The positioning of the peeling member on the fixing roller side is performed on the surface of the fixing roller, and the positioning of the peeling member on the pressure roller side is performed on the bearing surface of the pressure roller, so that recording from the fixing roller and the pressure roller is performed. The peelability of the medium can be improved.

In this embodiment, as shown in FIG. 12, the fixing roller 210 and the pressure roller 220 are arranged in a substantially horizontal state, and the recording medium 500 is discharged from the fixing nip 340 upward. but for the tangent S of the outlet 341 of the fixing nip portion 340, the arrangement angle theta _a of the release member 310 is preferably set in a range of -5 to 25 °. By setting the arrangement angle θ _A of the peeling member 310 with respect to the tangent S of the outlet 341 of the fixing nip portion 340 to a value in such a range, the image is less likely to cause streaks and the peelability is improved. . Incidentally, the arrangement angle theta _A, the fixing roller 210 side "+", the pressure roller side - a "."

In addition, the fixing roller 210 and the pressure roller 220 have, for example, substantially constant outer diameters in the respective axial directions (which may have a substantially cylindrical shape, but the outer diameters are small in the vicinity of both ends. It may have a so-called crown shape that is large in the vicinity of the central portion, or a so-called reverse crown shape in which the outer diameter is large in the vicinity of both end portions and small in the vicinity of the central portion.
For example, when the fixing roller 210 and the pressure roller 220 have reverse crown shapes as shown in FIG. 13, the cross-sectional shape of the peeling member 310 is preferably as shown in FIG. In addition, when the fixing roller 210 and the pressure roller 220 have a crown shape as shown in FIG. 15, the cross-sectional shape of the peeling member 310 is preferably as shown in FIG.

  In this way, when the peeling member 310 disposed along the fixing roller 210 has a shape that follows the shape of the outlet 341 of the nip portion 340, the peeling member 310 on the fixing roller 210 side is peeled off at the time of peeling. Effectively eliminates adverse effects caused by increased contact between the side edge and the recording medium, and the contact pressure between the two is concentrated in part, for example, wrapping of the recording medium, disturbance in the formed image, generation of streaks, etc. It can be prevented and suppressed.

  As shown in FIG. 17, in the fixing device 190, the gap G <b> 2 [μm] between the fixing roller 210 and the peeling member 310 near the axial end of the fixing roller 210 is the center in the axial direction of the fixing roller 210. It is preferable that the gap is larger than the gap G1 [μm] between the fixing roller 210 and the peeling member 310 in the vicinity of the portion. By satisfying such a relationship, the following effects can be obtained.

  That is, since the gap between the peeling member 310 and the fixing roller 210 is small in the vicinity of the central portion in the length direction, the gap management can be easily performed without greatly deteriorating the peeling property, and the fixing device 190 can be manufactured. It becomes easy. Further, even when a foreign substance enters or a paper jam occurs, it is difficult to cause damage to the peeling member 310 and the fixing roller 210 due to these, and the durability and reliability of the peeling member 310 and the fixing roller are improved, and fixing is performed. The durability and reliability of the apparatus 190 and the image forming apparatus 10 are also improved. Note that the relationship between G1 and G2 as described above can be obtained by, for example, forming the peeling member 310 into a bow shape, forming the tip 310f of the peeling member 310 into a bow shape, or forming the fixing roller 210 into a crown shape. Can be satisfied.

  In the fixing device as described above, the length of the fixing nip 340 is such that the time required for the toner particles to pass through the fixing nip 340 is 0.02 to 0.2 seconds. Is preferable, and 0.03 to 0.1 second is more preferable. When the time required for the toner particles to pass through the fixing nip portion 340 is within such a range, the toner is heated up to the melting temperature, and the toner is not melted sufficiently, and the releasability to the fixing roller is sufficient. Secured.

  The fixing device 190 is suitable for high-speed printing (high-speed fixing, high-speed image formation). Specifically, the feeding speed (feeding speed) of the recording medium 500 is 0.05 to 1.0 m / sec. It is preferable that it is 0.2 to 0.5 m / sec. As described above, according to the present invention, even when the toner is fixed to the recording medium 500 at a relatively high speed, it is possible to prevent the image from causing streaking or disturbance, and the recording medium 500 may be entangled. It is difficult to cause poor peeling.

Further, the temperature of the fixing nip portion 340 during operation is preferably 100 to 220 ° C, and more preferably 120 to 200 ° C. When the temperature of the fixing nip portion 340 is within such a range, it is possible to sufficiently prevent a decrease in toner fixing strength due to a temperature drop (temperature drop) when the paper passes. As described above, according to the present invention, it is possible to form an image having a sufficient fixing strength at a relatively low fixing temperature and a low gloss even at a relatively high fixing temperature.
Further, the fixing setting temperature (setting temperature on the surface of the fixing roller 210) during operation is preferably 110 to 220 ° C, and more preferably 130 to 200 ° C. If the set temperature of the fixing roller 210 is within such a range, both the fixing strength of the toner can be secured and the temperature rise time (warm-up time) can be shortened.

  As described above, the fixing device 190 described above is suitable for high-speed printing (high-speed fixing, high-speed image formation). However, in such a fixing device, since the toner is in a high temperature state even when the recording medium on which the toner is fixed comes into contact with the peeling member, when the conventional toner is used, the toner comes into contact with the peeling member. There is a possibility that the fixed image may be disturbed. Further, when the fixed toner is in a molten state (low viscosity state) and comes into contact with the release member, it may be difficult to reliably release the recording medium.

  On the other hand, the fixing device 190 described above can suitably apply the toner applied to the present invention. That is, since the toner applied to the present invention contains amorphous polyester having a relatively low softening point, the toner is surely fixed to the recording medium when passing through the fixing nip 340. Since the toner applied to the invention contains a block polyester having a crystalline block, it tends to have a crystal having a high hardness and an appropriate size deposited therein. The presence of such crystals makes it possible to prevent the melt viscosity of the toner from being lower than a predetermined value even when the temperature is relatively high, such as during fixing, and partially during fixing. There will be a hard site. As a result, even when the fixed image of the toner comes into contact with the peeling member, the formed image is unlikely to be disturbed or distorted. Further, in the recording medium on which the toner applied to the present invention is fixed, the peeling failure is not particularly likely to occur and the peeling member reliably peels off the fixing roller.

Although the image forming method of the present invention has been described based on the preferred embodiments, the present invention is not limited to this.
For example, the toner applied to the present invention is not limited to the toner manufactured by the method described above. For example, in the above-described embodiment, the toner manufacturing powder obtained through the granulation process has been described as being obtained by performing an external addition process. However, the powder is obtained by the granulation process without performing the external addition process. The powder (toner production powder) may be used as the toner as it is.

In the embodiment described above, the rutile-anatase type titanium oxide has been described as being added as an external additive. For example, by using the rutile-anatase-type titanium oxide as one component of the raw material provided for the kneading step. The toner may be contained in the toner.
In the above-described embodiment, ΔT obtained by measuring the endothermic peak of the melting point by differential scanning calorimetry (DSC) has been described as an index indicating crystallinity. However, the index indicating crystallinity is not limited to this. For example, as an index representing crystallinity, a crystallinity measured by a density method, an X-ray method, an infrared method, a nuclear magnetic resonance absorption method, or the like may be used.

In the above-described embodiment, the toner manufacturing powder is described as being obtained by a pulverization method. However, the toner manufacturing powder may be manufactured by other methods such as a spray drying method or a polymerization method. Good.
In the above-described embodiment, the configuration in which the thermal spheronization process is performed under dry conditions has been described. However, the thermal spheronization process may be performed under wet conditions such as in a solution.

Moreover, although embodiment mentioned above demonstrated the structure which uses a continuous twin-screw extruder as a kneading machine, the kneading machine used for kneading | mixing a raw material is not limited to this. For kneading the raw materials, for example, various kneaders such as a kneader, a batch type triaxial roll, a continuous biaxial roll, a wheel mixer, and a blade type mixer can be used.
In the illustrated configuration, the kneader having two screws has been described. However, the number of screws may be one or three or more.

  In the above-described embodiment, the configuration using the belt type as the cooler has been described. However, for example, a roll type (cooling roll type) cooler may be used. Moreover, the cooling of the kneaded material extruded from the extrusion port of the kneader is not limited to the one using the above-described cooling machine, and may be performed by air cooling or the like, for example.

In addition, the fixing device and the image forming apparatus applied to the present invention are not limited to those described in the above-described embodiments. It can be replaced with that of the configuration.
For example, in the above-described embodiment, the contact type fixing device has been described. However, the present invention is not limited to such a contact type fixing device, and may be applied to a non-contact type fixing device. Good.

[1] Manufacture of polyester Prior to toner manufacture, the following three polyesters A, B, C, D, and E were manufactured.
[1.1] Production of Polyester A (Amorphous Polyester) First, neopentyl glycol: 36 mol parts, ethylene glycol: 36 mol parts, 1,4-cyclohexanediol: 48 mol parts, dimethyl terephthalate: 90 mol parts A mixture of 10 parts by mole of phthalic anhydride was prepared.

In a 2-liter four-necked flask, a reflux condenser, a distillation tower, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were installed according to a conventional method, and a mixture of the alcohol component and the carboxylic acid component: 1000 g , 1 g of an esterification condensation catalyst (titanium tetrabutoxide (PPB)) was placed in the 2-liter four-necked flask. Thereafter, the esterification reaction was allowed to proceed at a material temperature of 170 ° C. while the generated water and methanol were allowed to flow out of the distillation tower. When water and methanol no longer flowed out of the distillation column, the distillation column was removed from the 2-liter four-necked flask and connected to a vacuum pump. With the pressure in the system reduced to 5 mmHg or less, the temperature was set to 190 ° C., and the stirring rotation speed: stirring at 150 rpm, the free diol generated in the condensation reaction was discharged out of the system, and the resulting reaction product Was polyester A (PES-A).
With respect to the obtained polyester A, an attempt was made to measure the endothermic peak of the melting point with a differential scanning calorimeter. As a result, a sharp peak that could be determined to be an absorption peak at the melting point could not be confirmed. Further, the softening point _{T 1/2} of the polyester A is 114 ° C., a glass transition point The _{T g,} 63 ° C., a weight average molecular weight Mw was 2.3 × 10 ^4.

[1.2] Manufacture of polyester B (block polyester) In a 2 liter four-necked flask, a reflux condenser, a distillation tower, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were installed according to a conventional method. Polyester A obtained in [1.1]: mixture of 80 parts by mole, 1,4-butanediol as an alcohol component: 10 parts by mole and dimethyl terephthalate as a carboxylic acid component: 10 parts by mole, Esterification condensation catalyst (titanium tetrabutoxide (PPB)): 1 g was placed in the 2-liter four-necked flask. Thereafter, the esterification reaction was allowed to proceed at a material temperature of 170 ° C. while the generated water and methanol were allowed to flow out of the distillation tower. When water and methanol no longer flowed out of the distillation column, the distillation column was removed from the 2-liter four-necked flask and connected to a vacuum pump. With the pressure in the system reduced to 5 mmHg or less, the temperature was set to 190 ° C., and the stirring rotation speed: 150 rpm, the free diol generated in the condensation reaction was discharged out of the system, and the resulting reaction product Was polyester B (PES-B).

The center value _Tmp of the endothermic peak of the melting point of polyester B measured with a differential scanning calorimeter was 223 ° C., and the shoulder peak value T _ms was 212 ° C. Moreover, from the differential scanning calorimetric analysis curve obtained by the measurement, the heat of fusion E _f of polyester B determined was 13 mJ / mg. Further, the softening point _{T 1/2} of the polyester B is 157 ° C., a glass transition point The _{T g,} 68 ° C., a weight average molecular weight Mw was 7.4 × 10 ^4.

[1.3] Manufacture of polyester C (block polyester) In a 2-liter four-necked flask, a reflux condenser, a distillation tower, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were installed according to a conventional method. Polyester A obtained in [1.1]: 70 mol parts, 1,4-butanediol as an alcohol component: 15 mol parts and dimethyl terephthalate as a carboxylic acid component: 15 mol parts: 1000 g Esterification condensation catalyst (titanium tetrabutoxide (PPB)): 1 g was placed in the 2-liter four-necked flask. Thereafter, the esterification reaction was allowed to proceed at a material temperature of 200 ° C. while the generated water and methanol were allowed to flow out of the distillation tower. When water and methanol no longer flowed out of the distillation column, the distillation column was removed from the 2-liter four-necked flask and connected to a vacuum pump. With the pressure in the system reduced to 5 mmHg or less, the temperature was set to 220 ° C., and the stirring rotation speed: stirring at 150 rpm, the free diol generated in the condensation reaction was discharged out of the system, and the resulting reaction product Was polyester C (PES-C).

The center value _Tmp of the endothermic peak of the melting point of the polyester C measured by using a differential scanning calorimeter was 218 ° C., and the shoulder peak value T _ms was 205 ° C. Moreover, from the differential scanning calorimetric analysis curve obtained by the measurement, the heat of fusion E _f of the polyester C determined was 15 mJ / mg. Polyester C had a softening point T _1/2 of 148 ° C., a glass transition point T _g of 63 ° C., and a weight average molecular weight Mw of 2.6 × 10 ⁴ .

[1.4] Production of Polyester D (Amorphous Polyester) First, neopentyl glycol: 36 mol parts, ethylene glycol: 36 mol parts, 1,4-cyclohexanediol: 48 mol parts, dimethyl terephthalate: 90 mol parts A mixture of 10 parts by mole of phthalic anhydride was prepared.
In a 2-liter four-necked flask, a reflux condenser, a distillation tower, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were installed according to a conventional method, and a mixture of the alcohol component and the carboxylic acid component: 1000 g , 1 g of an esterification condensation catalyst (titanium tetrabutoxide (PPB)) was placed in the 2-liter four-necked flask. Thereafter, the esterification reaction was allowed to proceed at a material temperature of 200 ° C. while the generated water and methanol were allowed to flow out of the distillation tower. When water and methanol no longer flowed out of the distillation column, the distillation column was removed from the 2-liter four-necked flask and connected to a vacuum pump. With the pressure in the system reduced to 5 mmHg or less, the temperature was set to 220 ° C., and the stirring rotation speed: stirring at 150 rpm, the free diol generated in the condensation reaction was discharged out of the system, and the resulting reaction product Was polyester D (PES-D).
About the obtained polyester D, the measurement of the endothermic peak of melting | fusing point with a differential scanning calorimeter was tried. As a result, a sharp peak that could be determined to be an absorption peak at the melting point could not be confirmed. Polyester D had a softening point T _1/2 of 106 ° C., a glass transition point T _g of 57 ° C., and a weight average molecular weight Mw of 5.6 × 10 ³ .

[1.5] Manufacture of polyester E (polyester having high crystallinity, not block polyester) In a 2-liter four-necked flask, a reflux condenser, a distillation tower, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirring device Was installed according to a conventional method, and a mixture of 1,4-butanediol as an alcohol component: 50 parts by mole and dimethyl terephthalate as a carboxylic acid component: 60 parts by mole, an esterification condensation catalyst (titanium tetrabutoxide ( PPB)): 1 g was placed in the 2 liter 4 neck flask. Thereafter, the esterification reaction was allowed to proceed at a material temperature of 260 ° C. while water and methanol produced were allowed to flow out of the distillation tower. When water and methanol no longer flowed out of the distillation column, the distillation column was removed from the 2-liter four-necked flask and connected to a vacuum pump. With the pressure in the system reduced to 5 mmHg or less, the temperature was set to 280 ° C., and the stirring rotation speed: 150 rpm, the free diol generated in the condensation reaction was discharged out of the system, and the resulting reaction product Was polyester E (PES-E).

The center value _Tmp of the endothermic peak of the melting point of polyester E measured by using a differential scanning calorimeter was 228 ° C., and the shoulder peak value T _ms was 215 ° C. Moreover, from the differential scanning calorimetric analysis curve obtained by the measurement, the heat of fusion E _f of the polyester E determined was 35 mJ / mg. Further, the softening point _{T 1/2} of polyester D is 180 ° C., a glass transition point The _{T g,} 70 ° C., a weight average molecular weight Mw, was 2.0 × 10 ^4.

In addition, the measurement of melting | fusing point, softening point, glass transition point, and weight average molecular weight about each said resin material was performed as follows.
The melting point _Tm was measured using a differential scanning calorimeter DSC (Seiko Electronics Co., Ltd., DSC220 type) as follows. First, the resin sample was heated to 200 ° C. at a rate of temperature increase: 10 ° C./min, and then decreased to 0 ° C. at a rate of temperature decrease: 10 ° C./min. Thereafter, the temperature was increased at a rate of temperature increase of 10 ° C./min, and the maximum endothermic peak temperature (at the time of 2nd run) due to crystal melting at that time was determined as the melting point T _m .

The softening point T1 _{/ 2} was measured using a capillary type rheometer (manufactured by Shimadzu Corporation, flow tester CFT-500 type). Sample amount: 1 g, die hole diameter: 1 mm, die length: 1 mm, load: 20 kgf, preheating time: 300 seconds, measurement start temperature: 50 ° C., heating rate: 5 ° C./min The temperature (1/2 method temperature) at the time when the fluctuation range of the piston stroke between the start time point and the outflow end time point was _1/2 was determined as the softening point T _1/2 (see FIG. 3).

Measurement of the glass transition point The T _g, differential scanning calorimeter DSC (Seiko Denshi Kogyo Co., Ltd., DSC220 type) was used to perform simultaneously with the measurement of the melting point. The tangent of the maximum differential value (maximum slope point of DSC data) between two points of the baseline designated point before and after the glass transition at the 2nd run described in the above melting point measurement method, and the extension of the baseline before the glass transition the intersection of the line was determined as the glass transition temperature T _g.

The weight average molecular weight Mw was measured using gel permeation chromatography GPC (manufactured by Tosoh Corporation, model HLC-8220) as follows.
First, 1 g of a resin sample was dissolved in THF (tetrahydrofuran) to obtain 1 ml of a THF solution (including insoluble matter). This THF solution is poured into a sample bottle dedicated to centrifugation, centrifuged with a centrifuge at 2000 rpm for 5 minutes, and filtered with a supernatant liquid prep LCR13-LH (pore size: 0.5 μm), A filtrate was obtained.

  The filtrate thus obtained was subjected to gel permeation chromatography GPC (manufactured by Tosoh Corporation) under the conditions of column: TSKgel SuperHZ4000 + SuperHZ4000 (manufactured by Tosoh Corporation), flow rate: 0.5 mL / min, temperature: 25 ° C., solvent: THF. HLC-8220 type), and the weight average molecular weight Mw of the resin sample was determined based on the resulting chart. Note that monodisperse polystyrene was used as the standard sample.

[2] Production of Toner A toner was produced as follows.
(Example 1)
First, polyester A: 85 parts by weight as an amorphous polyester, polyester B: 15 parts by weight as a block polyester, quinacridone (PR 122): 6 parts by weight as a colorant, chromium salicylate complex (Bontron E as a charge control agent) -81): 1 part by weight and 2 parts by weight of carnauba wax as a wax were prepared.
These components were mixed using a 20 L type Henschel mixer to obtain a raw material for toner production.

Next, this raw material (mixture) was kneaded using a twin-screw kneading extruder (Toshiba Machine Co., Ltd., TEM-41 type) as shown in FIG.
The total length of the process section of the biaxial kneading extruder was 160 cm, the length of the first region was 32 cm, the length of the second region was 80 cm, and the length of the third region was 16 cm.
In addition, the temperature of the raw material in the process part was set to 240 ° C. in the first region, 100 ° C. in the second region, and 100 ° C. in the third region.
The screw rotation speed was 120 rpm, and the raw material charging speed was 20 kg / hour.
The time required for the raw material to pass through the first region, determined from such conditions, is about 1.5 minutes, and the time required to pass through the second region is about 3 minutes.

The raw material (kneaded material) kneaded in the process part was extruded outside the biaxial kneading extruder through the head part. The temperature of the kneaded material in the head part was adjusted to 110 ° C.
Thus, the kneaded material extruded from the extrusion port of the biaxial kneading extruder was cooled using a cooling machine as shown in FIG. The temperature of the kneaded material immediately after the cooling step was about 46 ° C.
The cooling rate of the kneaded product was −7 ° C./second. In addition, the time required from the end of the kneading process to the end of the cooling process was 10 seconds.

The kneaded product cooled as described above was coarsely pulverized (average particle size: 1 to 2 mm), and then finely pulverized. A hammer mill was used for coarse pulverization of the kneaded product, and a jet mill (200 AFG, manufactured by Hosokawa Micron Corporation) was used for fine pulverization. The fine pulverization was performed at a pulverization air pressure: 550 [kPa] and a rotor rotation speed: 7000 [rpm].
The pulverized material thus obtained was classified with an airflow diverter (manufactured by Hosokawa Micron Corporation, 100 ATP).

Thereafter, an external additive was applied to the classified powder for toner production to obtain a toner. Application of the external additive was performed by mixing 100 parts by weight of the powder for toner production and 2.5 parts by weight of the external additive using a 20 L type Henschel mixer. As external additives, negatively chargeable small particle size silica (average particle size: 12 nm): 1 part by weight, negatively chargeable large particle size silica (average particle size: 40 nm): 0.5 part by weight, rutile anatase A type of titanium oxide (substantially spindle shape, average major axis diameter: 30 nm): 1 part by weight was used. In addition, as the negatively chargeable silica (negatively chargeable small particle size silica, negatively chargeable large particle size silica), those subjected to surface treatment (hydrophobization treatment) with hexamethyldisilazane were used. In addition, as the rutile-anatase type titanium oxide, the ratio of the rutile-type titanium oxide crystal structure to the anatase-type titanium oxide is 90:10 and absorbs light in the wavelength region of 300 to 350 nm. A thing was used.
However, in the production of the toner as described above, the change rate of the weight average molecular weight of each resin material before and after the production is within ± 10%, and the change amount of the melting point, the softening point, and the glass transition point is within ± 10 ° C. The conditions were as follows.

  The average particle size of the finally obtained toner was 7.5 μm. The obtained toner had an average circularity R of 0.91. The acid value of the toner was 0.8 mgKOH / g. The average length of the crystals in the toner was 600 nm. Further, the coverage of the external additive in the obtained toner was 160%. Further, the ratio of the rutile-anatase-type titanium oxide contained in the toner as a free external additive (free rate) was 1.7%.

The circularity was measured in a water dispersion system using a flow type particle image analyzer (manufactured by Sysmex Corporation, FPIA-2000). However, the circularity R is represented by the following formula (I).
R = L ₀ / L ₁ (I)
(Where L ₁ [μm] is the circumference of the projected image of the toner particles to be measured, and L ₀ [μm] is the circumference of a perfect circle having an area equal to the area of the projected image of the toner particles to be measured) Represents length)
Further, the average length of the crystals in the toner was obtained from the result of measurement using a transmission electron microscope (TEM).

(Examples 2 to 4)
A toner was produced in the same manner as in Example 1 except that the addition amounts of polyester A and polyester B in the raw material used in the mixing step were as shown in Table 1.
(Comparative Example 1)
A toner was produced in the same manner as in Example 1 except that polyester C was used instead of polyester B.

(Comparative Example 2)
A toner was produced in the same manner as in Example 1 except that polyester D was used instead of polyester A, and polyester C was used instead of polyester B.
(Comparative Example 3)
A toner was produced in the same manner as in Example 1 except that 100 parts by weight of polyester D was used instead of 85 parts by weight of polyester A and 15 parts by weight of polyester B.
(Comparative Example 4)
A toner was produced in the same manner as in Example 1 except that polyester D was used instead of polyester A, and polyester E was used instead of polyester B.

  Constituent components of the toners of the respective Examples and Comparative Examples are shown in Table 1, and the average particle diameter, average circularity R, acid value, average length of crystals in the toner, coverage of external additives, Table 2 summarizes the liberation rate of rutile-anatase type titanium oxide. In the table, polyester A, polyester B, polyester C, polyester D, and polyester E are indicated by PES-A, PES-B, PES-C, PES-D, and PES-E, respectively. Indicated by CCA.

For the toners of the examples and comparative examples, Δt = 0.05 [seconds], and the relaxation elastic modulus G of the toner at 0.01 seconds is the initial relaxation elastic modulus G (0.01) [Pa]. Further, the ratio of G (0.01) [Pa] to G (Δt) [Pa] when the relaxation elastic modulus G (Δt) [Pa] of the toner is Δt seconds, G (0.01) / G (Δt) was determined as follows.
First, about 1 g of toner was sandwiched between parallel plates and melted by heating to prepare a height of 1.0 to 2.0 mm. The samples thus obtained were subjected to viscoelasticity measurement under the following measurement conditions in the stress relaxation measurement mode using an ARES viscoelasticity measuring apparatus (manufactured by Rheometric Scientific F.E.).
・ Measurement temperature: 150 ℃
-Strain applied amount: Maximum strain in the wire diameter region-Geometry: Parallel plate (25mm diameter)
According to the above measurement, the initial relaxation elastic modulus (relaxation elastic modulus at 0.01 seconds): G (0.01) [Pa], relaxation elastic modulus at Δt = 0.05 seconds: G (Δt) [ Pa] was determined. The values of G (0.01) / G (Δt) obtained from these results are also shown in Table 2.

[3] Evaluation Each toner obtained as described above was evaluated for gloss, good fixing area, and development durability.
[3.1] Gloss First, a fixing device as shown in FIGS. 7 to 14 and 17 was manufactured. In this fixing device, the time Δt required for the toner to pass through the nip portion was set to 0.05 seconds. Using this fixing device, an image forming apparatus (color printer) as shown in FIGS. 5 and 6 was produced. An unfixed image sample was collected using this image forming apparatus, and the following test was performed with the fixing device of the image forming apparatus. The solid amount of the sample to be collected was adjusted to an adhesion amount of 0.40 to 0.50 mg / cm ² .

In the state where the surface temperature of the fixing roller of the fixing device constituting the image forming apparatus is set to 160 ° C., a sheet of paper on which an unfixed toner image is transferred (manufactured by Seiko Epson, high-quality plain paper) is placed inside the fixing device By introducing the toner image, the toner image was fixed on the paper, the toner fixed on the paper was measured with a gloss meter (Angle was set to 75 °), and the presence or absence of gloss (gloss) was evaluated according to the following three-stage criteria. .
A: There is almost no gloss. : Gross value ≦ 20
○: Slightly glossy. : 20 <gross value ≦ 30
X: Glossy. : Gross value> 30

[3.2] Good Fixing Area Paper on which an unfixed toner image is transferred in a state where the surface temperature of the fixing roller of the fixing device constituting the image forming apparatus used in [3.1] is set to a predetermined temperature. The toner image was fixed on the paper by introducing a high-quality plain paper (manufactured by Seiko Epson Co., Ltd.) into the fixing device, and the presence or absence of offset after fixing was visually confirmed.

Similarly, the set temperature of the surface of the fixing roller is sequentially changed within a range of 100 to 220 ° C., and the presence / absence of occurrence of offset at each temperature is confirmed. It was determined as “range” and evaluated according to the following three-stage criteria.
(Double-circle): The width | variety of a "good fixing area" is 60 degreeC or more.
○: The width of the “fixed good region” is 35 ° C. or more and less than 60 ° C.
X: The width of the “fixed good region” is less than 35 ° C.

[3.3] Durability of development Time after setting 30 g of toner in the developing device of the image forming apparatus used in [3.1] above, aging is performed without replenishment, and filming on the developing roller occurs Was measured and evaluated according to the following three-stage criteria.
(Double-circle): Filming generation | occurrence | production was not recognized even if 120 minutes or more passed after aging start.
○: Filming occurs 60 to 120 minutes after the start of aging.
X: Filming occurs in less than 60 minutes after the start of aging.
These results are summarized in Table 3.

  As is apparent from Table 3, the image forming method of the present invention was able to obtain a good low gloss image. In particular, the image forming method of the present invention can obtain a good low-gloss image while maintaining the fixing property and the development durability. Further, the gloss was evaluated in the same manner as described above by changing the fixing temperature within the range of good fixing. However, the image forming method of the present invention showed almost no gloss even in such a temperature range. I couldn't. In particular, extremely good results were obtained with a toner containing a polyester resin having a preferred composition.

On the other hand, with the toner of the comparative example, an image with sufficiently suppressed gloss (low gloss image) could not be obtained.
In particular, the toner of Comparative Example 3 containing no block polyester was weak against mechanical stress and inferior in development durability. Also, the fixability was inferior.
Further, the toner of Comparative Example 4 in which the amorphous polyester and the highly crystalline polyester D were used in combination without using the block polyester was inferior in compatibility between the resins, and inferior in low-temperature fixability and durability. .

  Further, each toner was passed through the nip portion of the fixing device, and the change amount of the relaxation elastic modulus G (t) in the passage time Δt [second] of the toner particles through the nip portion was measured. In each of the toners 1 to 13, the amount of change in the relaxation elastic modulus G (t) was 100 [Pa] or less. The temperature of the nip portion when the toner particles pass was 180 ° C.

  Further, as a colorant, instead of quinacridone (PR 122), copper phthalocyanine pigment, Pigment Red 57: 1, C.I. I. Except for using Pigment Yellow 93 and Carbon Black, toners were prepared in the same manner as in the above Examples and Comparative Examples, and the same evaluations were performed on these toners. As a result, the same results as those of the respective Examples and Comparative Examples were obtained.

FIG. 3 is a longitudinal sectional view schematically showing an example of the configuration of a kneader and a cooler used in a toner manufacturing method applied to the present invention. It is a model figure of the differential scanning calorimetry curve in the vicinity of melting | fusing point of block polyester obtained when differential scanning calorimetry is performed about block polyester. It is a flowchart for a softening point analysis. FIG. 4 is a diagram for explaining a method for measuring the amount of rutile-anatase type titanium oxide released from toner particles contained in toner. 1 is an overall configuration diagram showing a preferred embodiment of an image forming apparatus applied to an image forming method of the present invention. FIG. 6 is a cross-sectional view of a developing device included in the image forming apparatus of FIG. 5. FIG. 6 is a perspective view showing a detailed structure of a fixing device used in the image forming apparatus of FIG. It is principal part sectional drawing of the fixing device of FIG. It is a perspective view of the peeling member which comprises the fixing device of FIG. It is a side view which shows the attachment state of the peeling member which comprises the fixing device of FIG. It is the front view which looked at the fixing device of FIG. 7 from the upper surface. It is a schematic diagram for demonstrating the arrangement | positioning angle of a peeling member with respect to the tangent in the exit of a nip part. It is a figure which shows typically the shape of a fixing roller and a pressure roller, and the shape of a nip part. It is sectional drawing in the XX line of Fig.13 (a). It is a figure which shows typically the shape of a fixing roller and a pressure roller, and the shape of a nip part. It is sectional drawing in the YY line | wire of Fig.15 (a). It is sectional drawing for demonstrating the gap of a fixing roller and a peeling member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Kneading machine 2 ... Process part 21 ... Barrel 22, 23 ... Screw 24 ... Fixing member 25 ... 1st area | region 26 ... 2nd area | region 27 ... 3rd area | region 28, 29 ... ... Temperature transition region 3 ... Head 31 ... Internal space 32 ... Extrusion port 33 ... Transverse area gradually decreasing part 4 ... Feeder 5 ... Raw material 6 ... Coolers 61, 62, 63, 64 ... Roll 611 , 621, 631, 641... Rotating shaft 65, 66... Belt 67... Discharge unit 7 .. Kneaded material 10... Image forming apparatus 20. ... Exposure device 60 ... Rotary development device 600 ... Support frame 601 ... Housing 603 ... Supply roller 604 ... Development roller 605 ... Regulator blade 605a ... Plate-like member 60 b ... elastic member 60Y ... yellow developing device 60M ... magenta developing device 60C ... cyan developing device 60K ... black developing device 70 ... intermediate transfer device 90 ... drive roller 100 ... driven roller 110 ...... Intermediate transfer belt 120 ...... Primary transfer roller 130 ...... Transfer belt cleaner 140 ...... Secondary transfer roller 150 ...... Feed cassette 160 ...... Pickup roller 170 ...... Recording medium conveyance path 190 ...... Fixing device 200 ...... Discharge tray 210... Fixing roller (heat fixing member) 210 a... Heat source 210 b... Cylindrical body 210 c .. Elastic layer 210 d... Rotating shaft 220 ... Pressure roller (pressure member) 220 b. ... Elastic layer 220d ... Rotating shaft 230 ... Transport path for double-sided printing 240 ... Housing 250 …… Bearing 260 …… Pressure lever 270 …… Pressure spring 280 …… Drive gear 290 …… Support shaft 300 …… Support shaft 310 …… Peeling member 310a …… Peeling part 310b …… Bending part 310c …… Supporting piece 310d …… Fitting hole 310e …… Guide part 310f …… Tip part 320 …… Peeling member 320a …… Peeling part 320e …… Guide part 330 …… Spring 340 …… Nip part 341 …… Nip outlet 500 …… Recording medium T ... Toner S ... Tangent G1 ... Gap G2 ... Gap

Claims (12)

Peeling for peeling from the fixing roller a recording medium that has passed through a fixing roller, a pressure roller pressed against the fixing roller, and a fixing nip formed by a contact portion between the fixing roller and the pressure roller. A fixing device having a member and a step of forming an image by fixing toner composed of a polyester resin as a main component to a recording medium with a toner.
The polyester resin includes a block polyester mainly composed of a block copolymer, and an amorphous polyester having lower crystallinity than the block polyester,
The block polyester has a crystalline block formed by condensing an alcohol component and a carboxylic acid component, and an amorphous block having lower crystallinity than the crystalline block,
When the weight average molecular weight of the block polyester is Mw (B) and the weight average molecular weight of the amorphous polyester is Mw (A), the relationship of 0.5 ≦ Mw (B) / Mw (A) <4 is satisfied. 4 × 10 ⁴ ≦ Mw (B) ≦ 3 × 10 ⁵
The image forming method, wherein a blending ratio of the block polyester and the amorphous polyester is 5:95 to 35:65 by weight.   The image forming method according to claim 1, wherein the fixing device has a recording medium feed speed of 0.05 to 1.0 m / sec.   The image forming method according to claim 1, wherein the peeling member is a plate-like member having a predetermined length in the axial direction of the fixing roller and / or the pressure roller.   4. The image forming method according to claim 1, wherein in the fixing device, the peeling member is disposed on the downstream side of the fixing nip portion in the recording medium conveyance direction. 5.   The image forming method according to claim 1, wherein the peeling member is disposed in proximity to the fixing roller and / or the pressure roller.   6. The image forming method according to claim 1, wherein the fixing device includes the fixing roller and the pressure roller arranged in a substantially horizontal state.   The image according to any one of claims 1 to 6, wherein the fixing device includes the peeling member so that a gap between the fixing roller and the peeling member is substantially constant during operation. Forming method.   The said peeling member is arrange | positioned along the axial direction of the said fixing roller, and has a shape which follows the shape of the exit of the said fixing nip part. Image forming method. The arrangement angle θ _A of the peeling member with respect to the tangent to the exit of the fixing nip portion is −5 to + 20 ° when the fixing roller side is a positive angle and the pressure roller side is a negative angle. Item 9. The image forming method according to any one of Items 1 to 8.   The fixing device extends in the axial direction of the fixing roller and the pressure roller, and is disposed on the downstream side of the fixing nip portion in the recording medium conveyance direction and in proximity to the fixing roller; A peeling member disposed in the vicinity of the pressure roller, positioning the peeling member on the fixing roller side on the surface of the fixing roller, and positioning the peeling member on the pressure roller side The image forming method according to claim 1, wherein the image forming method is performed on a roller bearing surface.   The image forming method according to claim 10, wherein the fixing device has an axial length of the pressure roller shorter than that of the fixing roller, and the bearing is provided in an empty space.   In the fixing device, the gap G2 [μm] between the fixing roller and the peeling member in the vicinity of the end portion in the axial direction of the fixing roller has an area near the center portion in the axial direction of the fixing roller. 12. The image forming method according to claim 1, wherein the image forming method is larger than a gap G1 [μm] with the peeling member.

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