JP2019101073A - Image forming method - Google Patents

Abstract

To provide an image forming method that can prevent sticking of an output image recording medium, even when images largely different in coverage are printed on the same surface of the image recording medium.SOLUTION: An image forming method of the present invention is an image forming method for eliminating a residual charge of an image on an image recording medium to form an image, and includes: an image forming step of fixing a toner onto the image recording medium to form a toner image; and a voltage application step of applying a voltage having a polarity opposite to that of a surface potential of the toner image with a voltage application unit. A toner base particle of the toner contains a mold release agent; the mold release agent contains a first mold release agent component containing ester wax and a second mold release agent component containing microcrystalline wax; the content of the first mold release agent component is within a range of 40 to 98 mass% of the total mold release agent; the content of the second mold release agent component is within a range of 2 to 60 mass% of the total mold release agent.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming method, and in particular, to suppress sticking of an output image recording medium even in the case where images with greatly different coverage are printed in the same plane of the image recording medium in a high-speed machine. The present invention relates to providing an image forming method that can

  Conventionally, in an electrophotographic image forming method for forming a visible image by electrophotography, a toner image formed by an electrostatic charge image developing toner (hereinafter, also simply referred to as "toner") on a recording medium such as paper is fixed. As a method of fixing the heat roller, a heat roller fixing method is widely used in which a recording medium on which a toner image is formed is fixed by passing it between a heating roller and a pressure roller. A high heat capacity is required for the heating roller in order to ensure the fixing property in this heat roller fixing system, that is, the adhesion of the toner to the recording medium such as paper.

In recent years, the demand for energy saving has also been increasing for electrophotographic image forming apparatuses from the viewpoint of the prevention of global warming, and therefore, particularly for electrophotographic image forming apparatuses adopting a heat roller fixing method. As a technique for reducing the amount of heat required for fixing a toner image, that is, a technique for reducing the fixing temperature has been considered.
In order to lower the fixing temperature, it is necessary to lower the melting temperature and the melt viscosity of the binder resin constituting the toner base particles, but in order to lower the melting temperature and the melt viscosity of the binder resin, glass of the binder resin Lowering the transition point or molecular weight adversely affects the storage stability of the toner. As a technique for solving this problem, core / shell toner base particles in which the outermost layer of toner base particles is covered with a heat resistant resin have been proposed.

However, even in the case where a toner having both low temperature fixing ability and heat resistant storage property is used, in the process in which low temperature fixing is promoted, the charge stored in the toner is not sufficiently released. As a result, it was found that a phenomenon occurs in which the image is charged, and the images stick to each other, and further, the stacked sheets having the image stick.
By applying a voltage of the reverse polarity to the surface potential of the sheet to the sheet after fixing according to the coverage (printing rate) of the toner image, the surface potential of the sheet after fixing is canceled and the sheet is stuck. A method for improvement has been proposed (see Patent Document 1).
However, when high coverage images are printed on both sides, it has not been possible to obtain a sufficient charge removal effect. In particular, even when image patterns having different coverages are mixed in the same plane, it is difficult to obtain a stable static elimination effect by this method.
Therefore, a technique that does not cause sticking between images in the low temperature fixing process has been desired.

JP, 2016-122156, A

  The present invention has been made in view of the above problems and circumstances, and a problem to be solved by the present invention is that an output image recording medium is obtained even when an image having a greatly different coverage is printed in the same plane with a high speed machine. An image forming method capable of suppressing sticking is provided.

In order to solve the above problems, the present inventor uses a developer containing toner in which the type of the release agent component and the content of each release agent component are specified in the process of examining the cause of the above problems and the like. By forming a toner image on the image recording medium and applying a voltage having a reverse polarity to the surface potential of the toner image, even when an image having a significantly different coverage is printed on the same surface of the image recording medium. It has been found that it is possible to provide an image forming method capable of suppressing sticking of an output image recording medium, resulting in the present invention.
That is, the above-mentioned subject concerning the present invention is solved by the following means.
1. An image forming method for forming an image by removing residual charge of an image on an image recording medium, comprising:
An image forming step of fixing a toner on the image recording medium to form a toner image;
And V. applying a voltage having a polarity opposite to that of the surface potential of the toner image by a voltage application unit.
The toner contains toner base particles and an external additive, and the toner base particles contain a release agent.
The releasing agent contains a first releasing agent component containing an ester wax and a second releasing agent component containing a microcrystalline wax.
The content of the first release agent component is in the range of 40 to 98% by mass with respect to the entire release agent, and
An image forming method, wherein the content of the second release agent component is in the range of 2 to 60% by mass with respect to the entire release agent.

  2. 2. The image forming method according to claim 1, wherein the content of the releasing agent is in the range of 5.0 to 12.5% by mass with respect to the toner base particles.

3. The content of the first release agent component is in the range of 60 to 98% by mass with respect to the entire release agent, and
3. The image forming method according to item 1 or 2, wherein the content of the second release agent component is in the range of 2 to 40% by mass with respect to the entire release agent.

4. The content of the first release agent component is in the range of 80 to 98% by mass with respect to the entire release agent, and
The content of the second release agent component is in the range of 2 to 20% by mass with respect to the entire release agent, according to any one of the items 1 to 3, Image formation method described

  5. The image forming method according to any one of items 1 to 4, wherein the toner base particles contain a crystalline polyester resin.

  6. The image according to item 5, wherein the crystalline polyester resin comprises a hybrid crystalline polyester resin in which a crystalline polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene are chemically bonded. Formation method.

An image forming method capable of suppressing sticking of an output image recording medium even when an image with greatly different coverage is printed on the same surface of the image recording medium by the above means of the present invention in the high speed machine. Can be provided.
The mechanism for expressing the effect of the present invention or the mechanism of action is not clear but is presumed as follows.
In the conventional method of discharging electricity from an image recording medium by a voltage application process, it is necessary to control the applied voltage in detail according to the coverage of the first and second surfaces of the sheet (image recording medium). And the recharging of the paper could not be reliably suppressed. This is because the larger the toner layer thickness on the first surface (the higher the coverage), the higher the resistance of the toner layer and the easier it is for the second surface to be recharged.
Further, as shown in FIG. 3A, in the case where an image whose coverage is greatly different is printed within the same surface of the sheet, positive charge is generated only on the toner image 210A of the first surface 101 on the sheet immediately after fixing. In order to remove the charge, the same amount of charge as the positive charge stored in the toner image 210A of the first surface 101 is applied to the sheet immediately after fixing (to apply a high voltage) to the sheet immediately after fixing. Then, although the positive charges obtained in the toner image 210A on the first surface 101 cancel each other and become almost uncharged, the positive charges are stored in the toner image 220A on the second surface 102.
On the other hand, as shown in FIG. 3B, about half of the positive charge stored in the toner image 210A of the first surface 101 was applied to the sheet immediately after fixing (the low voltage was applied). In this case, the charge stored in the toner image 210A on the first surface 101 is not charged in the low coverage area, but is stored in the high coverage area. Similarly, the charge stored in the toner image 220A on the second surface 102 is also free of charge in the low coverage area, but is stored in the high coverage area.
Therefore, the design on the toner side is important as a method of discharging the image recording medium by the voltage application process.
That is, the content of the first release agent component containing ester wax and the content of the second release agent component containing microcrystalline wax are specified, and a toner image is formed on the image recording medium, and the toner image By applying a voltage having a polarity opposite to that of the surface potential of the toner, it is possible to suppress the recharging of the toner image as described above. It is considered that this is because the ester wax present on the image surface has changed the electrical properties of the image surface.
The releasing agent (wax) present in the toner exudes to the interface between the image surface and the fixing member by heat at the time of fixing, and exerts a releasing effect. Therefore, a large amount of wax is present on the image surface. In general, waxes have lower resistance than polymers used for binder resins because they have a much lower molecular weight, and ester waxes having ester bonds in the molecule have particularly low resistance. Therefore, even when a high voltage is applied, the charge is unlikely to remain on the surface of the toner image, and the charge leaks to the member for adjusting the charge, so it is presumed that the image is less likely to be recharged.
Furthermore, it has been found that when the microcrystalline wax is mixed with the ester wax in an appropriate amount, the effect of suppressing the recharging of the image is enhanced. The microcrystalline wax has an effect of reducing the crystal size of the wax in the toner, and the wax dispersed in a small crystal size tends to ooze out on the toner image surface, so the amount of wax on the image surface can be increased. It is inferred that the recharging suppression effect of If the content of the second releasing agent component containing microcrystalline wax is less than 2% by mass with respect to the whole releasing agent, the crystal size does not decrease, and therefore, the recharging suppression effect on the image surface is not sufficiently obtained. . On the other hand, if it exceeds 60% by mass, the resistance as a wax becomes high, so that the effect of suppressing the recharging of the image surface can not be sufficiently obtained.
As described above, even in the case where an image whose coverage is greatly different is printed in the same plane on the image recording medium, the sticking of the output image recording medium can be suppressed.

A diagram showing a schematic configuration of an image forming system used in the image forming method of the present invention Partially enlarged view of Figure 1 Diagram showing the voltage application process in the conventional example

The image forming method according to the present invention is an image forming method for forming an image by removing residual charge of the image on the image recording medium, and forming an image by fixing toner on the image recording medium to form a toner image. And applying a voltage having a polarity opposite to that of the surface potential of the toner image by a voltage application unit, wherein the toner includes toner base particles and an external additive, and the toner base particles are separated in the toner base particles. A mold release agent containing a mold release agent, and a first release agent component containing an ester wax, and a second release agent component containing a microcrystalline wax; the first release agent component The content of the second release agent component is in the range of 40 to 98% by mass with respect to the entire release agent, and the content of the second release agent component is 2 to 60 with respect to the entire release agent. It is characterized by being in the range of mass%.
This feature is a technical feature common to or corresponding to the following embodiments.

  In an embodiment of the present invention, the content of the releasing agent is in the range of 5.0 to 12.5% by mass with respect to the toner base particles, which is excellent in the diselectrification effect, and of the toner It is preferable in terms of chargeability and heat resistant storage stability.

  In addition, the content of the first release agent component is in the range of 60 to 98% by mass with respect to the entire release agent, and the content of the second release agent component is the above It is preferable in the point of the static elimination effect of an image that it exists in the range of 2-40 mass% with respect to the whole release agent.

  Furthermore, the content of the first release agent component is in the range of 80 to 98% by mass with respect to the entire release agent, and the content of the second release agent component is the above It is particularly preferable in view of the charge elimination effect of the image that the content is in the range of 2 to 20% by mass with respect to the entire release agent.

  Preferably, the toner base particles contain a crystalline polyester resin. By incorporating the crystalline polyester resin in the toner base particles, the crystalline polyester resin dispersed in the toner layer acts as a conductive path, and even in the case of an image of high coverage, charge removal is possible at a low voltage, and the toner layer Since the resistance of itself becomes low, it becomes difficult to be recharged, and the charge removal effect is excellent.

  Also. It is preferable that the crystalline polyester resin includes a hybrid crystalline polyester resin in which a crystalline polyester polymerized segment and a vinyl polymerized segment having a structural unit derived from styrene are chemically bonded. By the presence of the vinyl polymerized segment, the affinity between the hybrid resin and the amorphous resin is improved, and the dispersibility of the hybrid resin in the toner is improved, whereby the charge elimination effect of the image can be enhanced.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described. In the present application, “to” is used in the meaning including the numerical values described before and after that as the lower limit value and the upper limit value.

[Image formation method]
The image forming method according to the present invention is an image forming method for forming an image by removing residual charge of the image on the image recording medium, and forming an image by fixing toner on the image recording medium to form a toner image. And a voltage application step of applying a voltage having a polarity opposite to that of the surface potential of the toner image by a voltage application unit. Further, the toner contains toner base particles and an external additive, the toner base particles contain a release agent, and the release agent contains a first release agent component containing an ester wax, and microcrystalline. And a second releasing agent component containing a wax, wherein the content of the first releasing agent component is in the range of 40 to 98% by mass with respect to the entire releasing agent, and The content of the second release agent component is in the range of 2 to 60% by mass with respect to the entire release agent.

In the image forming process and the voltage applying process, an image forming apparatus for forming an image on an image recording medium, a charge adjusting apparatus 3 for adjusting charges of a recording medium on which an image is formed by the image forming apparatus, and an image forming apparatus And an image forming system including a stacker device for storing sheets on which an image has been formed.
Hereinafter, first, the image forming system will be described, and then the toner according to the present invention will be described.

[Image formation system]
As shown in FIG. 1, the image forming system 1 includes an image forming apparatus 2, a charge adjustment apparatus 3, and a stacker apparatus 4. The image forming device 2, the charge adjustment device 3, and the stacker device 4 are connected in order from the upstream side to the downstream side of sheet conveyance. Hereinafter, the image forming device 2, the charge adjustment device 3, and the stacker device 4 will be described in order.

<Image forming apparatus>
The image forming apparatus 2 includes a control unit 10, an operation panel unit 20, an image reading unit 30, an image forming unit 40, a fixing unit 50, and a sheet feeding unit 60.

  The control unit 10 includes a central processing unit (CPU) and various memories, and performs control of the respective units and various arithmetic processing in accordance with a program.

The operation panel unit 20 includes a touch panel, a ten key, a start button, a stop button, and the like, and is used to display various information and input various instructions.
The image reading unit 30 reads an image of a document and generates image data.

  The image forming unit 40 forms an image based on various data on a sheet (image recording medium) using a known image forming process such as an electrophotographic process. A transfer belt 41 is disposed at the central portion of the image forming unit 40. The transfer belt 41 is rotationally driven in the direction of arrow A, and a toner image formed on the surface of a photosensitive drum (not shown) is primarily transferred onto the transfer belt 41. Then, the toner image on the transfer belt 41, which has been primarily transferred, is secondarily transferred to the sheet.

  On the side surface of the transfer belt 41, four image forming units 42Y, 42M, 42C, 42K (hereinafter referred to as “signs” in the order of yellow (Y), magenta (M), cyan (C), black (K)) from the top A simplification is shown at 42). Each imaging unit 42 has a photosensitive drum. Around each photosensitive drum, a charger for uniformly charging the photosensitive drum surface, an exposure device for forming an electrostatic latent image according to image data on the uniformly charged photosensitive drum surface, and a toner image for the electrostatic latent image A developing device for developing the image.

  Further, primary transfer rollers 43Y, 43M, 43C and 43K (hereinafter, the reference numerals are simplified and indicated by 43) are disposed at positions facing the respective photosensitive drums with the transfer belt 41 interposed therebetween. The primary transfer roller 43 electrostatically attracts the toner image formed on the surface of the photosensitive drum and primarily transfers the toner image onto the transfer belt 41.

  Below the transfer belt 41, a secondary transfer roller 44 is disposed. The secondary transfer roller 44 secondarily transfers the toner image formed on the transfer belt 41 onto the conveyed sheet. When performing secondary transfer, by applying a high positive transfer voltage to the secondary transfer roller 44, a negatively charged toner image is electrostatically attracted to the sheet. The sheet on which the toner image has been transferred is supplied to the fixing unit 50.

  The fixing unit 50 heats and presses the toner image transferred onto the sheet by the fixing roller to fix the toner image on the sheet. The sheet on which the toner image is fixed by the fixing unit 50 is supplied to the charge adjusting device 3.

  The sheet feeding unit 60 accommodates the sheet 100 as a recording sheet used for printing. In the sheet feeding unit 60, sheet feeding cassettes 61 and 62 having a two-stage configuration are detachably disposed. For example, plain paper and coated paper are stored in the paper feed cassettes 61 and 62, respectively.

  A sheet conveyance path 74 is provided which extends from the sheet feeding cassettes 61 and 62 through the intermediate conveyance roller 71, the registration roller 72, the secondary transfer roller 44, the fixing unit 50, and the sheet discharge roller 73.

  Further, on the upper side of the sheet feeding cassettes 61 and 62, the registration roller 72 is branched from the conveyance path 74 on the downstream side of the fixing unit 50 via the switching gate 75 and located upstream of the image forming unit 40 in the sheet conveyance direction. A reverse conveyance path 76 which joins the conveyance path 74 immediately before is provided. On the downstream side of the reverse conveyance path 76, an ADU (Automatic Double-sided Unit) reverse roller 77 and an ADU intermediate conveyance roller 78 for reversing the front and back of the sheet and conveying the sheet to the downstream side of the reverse conveyance path 76 are provided. There is.

  In the reverse conveyance path 76 located immediately below the conveyance path 74 from the fixing unit 50 to the discharge roller 73, the sheet conveyed from the fixing unit 50 is inverted and conveyed to the discharge roller 73. A reversing roller 79 is disposed.

<Charge adjustment device>
The charge adjustment device 3 includes a voltage application unit 80 that applies a voltage to the sheet on which the toner image is fixed.

  As shown in FIG. 2, the voltage application unit 80 includes first and second conductive rubber rollers 81 and 82 disposed opposite to each other, and a power supply 83 for applying a voltage to the first and second conductive rubber rollers 81 and 82. It consists of

The first conductive rubber roller 81 is connected to the power supply 83, and the second conductive rubber roller 82 is grounded. The power supply 83 applies a positive voltage to the first conductive rubber roller 81. When a positive voltage is applied to the first conductive rubber roller 81, a positive charge is applied to the second surface (rear surface) 102 of the sheet 100. Further, the same negative charge as the positive charge given from the first conductive rubber roller 81 is induced to the second conductive rubber roller 82, and the positive charge on the first surface (surface) 101 of the paper 100 I will cancel each other.
The voltage application unit 80 is under constant current control by the control unit 10 of the image forming apparatus 2, determines the amount of charge to be applied to the sheet by the control unit 10, and is determined by a predetermined current value determined by the control unit 10. A current controlled voltage is applied to the sheet 100.

<Stacker device>
The stacker device 4 includes a storage unit 90 for stacking the sheets 100. The sheets on which the image is formed by the image forming apparatus 2 are sequentially supplied to the storage unit 90 and stacked.

  The image forming apparatus 2, the charge adjusting device 3, and the stacker device 4 may include components other than the components described above, or some of the components described above are not included. It is also good.

  In the image forming system 1 configured as described above, the sheet on which an image is formed by the image forming apparatus 2 passes through the charge adjustment device 3 and is accumulated in the stacker device 4. At this time, in order to prevent sticking of the sheets stacked in the stacker device 4, the charge adjusting device 3 adjusts the charged state of the sheets.

  Moreover, in the embodiment described above, the voltage application unit is constant current controlled. However, the control method of the voltage application unit is not limited to constant current control, and the voltage application unit may be, for example, constant voltage control.

  In the embodiment described above, the sheet is charged by applying a voltage to the sheet by the pair of conductive rubber rollers disposed opposite to each other. However, the voltage application unit that applies a voltage to the sheet to apply the charge is not limited to the pair of conductive rubber rollers, and may be a sawtooth electrode or a charger.

  In the embodiment described above, the image forming system having the image forming apparatus and the charge adjustment device has been described as an example. However, the charge adjustment device may be integral with the image forming device. In this case, a voltage application unit is provided inside the image forming apparatus.

The means and method for performing various processes in the image forming system according to the above-described embodiment can be realized by either a dedicated hardware circuit or a programmed computer. The program may be provided by a computer-readable recording medium such as a flexible disk and a compact disc read only memory (CD-ROM), or may be provided online via a network such as the Internet. In this case, the program recorded on the computer readable recording medium is usually transferred to and stored in a storage unit such as a hard disk.
Also, the program may be provided as a single application software or may be incorporated into the software of the apparatus as a function of the image forming system.

[toner]
The toner according to the present invention (toner for electrostatic charge image development) has toner base particles and an external additive, contains a release agent in the toner base particles, and the release agent contains an ester wax. 1 and a second release agent component containing microcrystalline wax, and the content of the first release agent component is 40 to 98 mass with respect to the entire release agent %, And the content of the second release agent component is in the range of 2 to 60% by mass with respect to the whole of the release agent.

In addition, the content of the releasing agent is in the range of 5.0 to 12.5% by mass with respect to the toner base particles, which is excellent in the diselectrification effect, and the charging characteristics of the toner and the heat resistant storage stability Preferred in terms of
In addition, the content of the first release agent component is in the range of 60 to 98% by mass with respect to the entire release agent, and the content of the second release agent component is the above It is preferable in the point of the static elimination effect of an image that it exists in the range of 2-40 mass% with respect to the whole release agent. Furthermore, the content of the first release agent component is in the range of 80 to 98% by mass with respect to the entire release agent, and the content of the second release agent component is the above It is particularly preferable in view of the charge elimination effect of the image that the content is in the range of 2 to 20% by mass with respect to the entire release agent.

<Toner base particle>
The toner base particles according to the present invention contain a release agent (wax).

«Release agent»
The release agent contains a first release agent component containing an ester wax and a second release agent component containing a microcrystalline wax.

(First mold release component)
The ester wax contained in the first release agent component according to the present invention contains at least an ester.
As the ester, any of monoesters, diesters, triesters and tetraesters can be used. For example, esters of higher fatty acids and higher alcohols having structures represented by the following general formulas (1) to (3) A trimethylolpropane triester having a structure represented by the following general formula (4), a glycerin triester having a structure represented by the following general formula (5), a structure represented by the following general formula (6) And pentaerythritol tetraesters, etc. can be mentioned.

General formula (1) R ¹ -COO-R ²
Formula _{^{(2) R 1 -COO- (CH}} 2) n -OCO-R 2
Formula _{^{(3) R 1 -OCO- (CH}} 2) n -COO-R 2
In formulas (1) to (3), R ¹ and R ² each independently represent a substituted or unsubstituted hydrocarbon group having 13 to 30 carbon atoms. R ₁ and R ₂ may be the same or different. n represents an integer of 1 to 30.
R ¹ and R ² each represent a hydrocarbon group having 13 to 30 carbon atoms, preferably a hydrocarbon group having 17 to 22 carbon atoms.
n represents an integer of 1 to 30, but preferably an integer of 1 to 12.

In general formula (4), R ^{1 to} R ⁴ each independently represent a substituted or unsubstituted hydrocarbon group having 13 to 30 carbon atoms. R ^{1 to} R ⁴ may be the same or different.
R ^{1 to} R ⁴ each represent a hydrocarbon group having 13 to 30 carbon atoms, preferably a hydrocarbon group having 17 to 22 carbon atoms.

In general formula (5), R ^{1 to} R ³ each independently represent a substituted or unsubstituted hydrocarbon group having 13 to 30 carbon atoms. R ^{1 to} R ³ may be the same or different.
R ^{1 to} R ³ each represent a hydrocarbon group having 13 to 30 carbon atoms, preferably a hydrocarbon group having 17 to 22 carbon atoms.

In general formula (6), R ^{1 to} R ⁴ each independently represent a substituted or unsubstituted hydrocarbon group having 13 to 30 carbon atoms. R ^{1 to} R ⁴ may be the same or different.
R ^{1 to} R ⁴ each represent a hydrocarbon group having 13 to 30 carbon atoms, preferably a hydrocarbon group having 17 to 22 carbon atoms.
The substituent which R ^{1 to} R ⁴ may have is not particularly limited as long as the effects of the present invention are not impaired. For example, a linear or branched alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon ring Group, aromatic heterocyclic group, non-aromatic hydrocarbon ring group, non-aromatic heterocyclic group, alkoxy group, cycloalkoxy group, aryloxy group, alkylthio group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, aryloxy group Carbonyl group, sulfamoyl group, acyl group, acyloxy group, amide group, carbamoyl group, ureido group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group or heteroarylsulfonyl group, amino group, halogen atom, fluorinated hydrocarbon group, cyano Group, nitro group, hydroxy group, thiol group, silyl group, deuterium source Etc. The.

As a specific example of the monoester having a structure represented by the above general formula (1), for example, compounds having structures represented by the following formulas (1-1) to (1-8) may be exemplified. it can.
Formula _{(1-1) CH 3 - (CH} 2) 12 -COO- (CH 2) 13 -CH 3
Formula _{(1-2) CH 3 - (CH} 2) 14 -COO- (CH 2) 15 -CH 3
Formula _{(1-3) CH 3 - (CH} 2) 16 -COO- (CH 2) 17 -CH 3
Formula _{(1-4) CH 3 - (CH} 2) 16 -COO- (CH 2) 21 -CH 3
Formula _{(1-5) CH 3 - (CH} 2) 20 -COO- (CH 2) 17 -CH 3
Formula _{(1-6) CH 3 - (CH} 2) 20 -COO- (CH 2) 21 -CH 3
Formula _{(1-7) CH 3 - (CH} 2) 25 -COO- (CH 2) 25 -CH 3
Formula _{(1-8) CH 3 - (CH} 2) 28 -COO- (CH 2) 29 -CH 3

As a specific example of the diester which has a structure represented by the said General formula (2) and General formula (3), the following formula (2-1)-(2-7), and a formula (3-1)- The compound which has a structure represented by-(3-3) can be illustrated.
Formula _{(2-1) CH 3 - (CH} 2) 20 -COO- (CH 2) 4 -OCO- (CH 2) 20 -CH 3
Formula _{(2-2) CH 3 - (CH} 2) 18 -COO- (CH 2) 4 -OCO- (CH 2) 18 -CH 3
Formula _{(2-3) CH 3 - (CH} 2) 20 -COO- (CH 2) 2 -OCO- (CH 2) 20 -CH 3
Formula _{(2-4) CH 3 - (CH} 2) 22 -COO- (CH 2) 2 -OCO- (CH 2) 22 -CH 3
Formula _{(2-5) CH 3 - (CH} 2) 16 -COO- (CH 2) 4 -OCO- (CH 2) 16 -CH 3
Formula _{(2-6) CH 3 - (CH} 2) 26 -COO- (CH 2) 2 -OCO- (CH 2) 26 -CH 3
Formula _{(2-7) CH 3 - (CH} 2) 20 -COO- (CH 2) 6 -OCO- (CH 2) 20 -CH 3

Formula _{(3-1) CH 3 - (CH} 2) 21 -OCO- (CH 2) 6 -COO- (CH 2) 21 -CH 3
Formula _{(3-2) CH 3 - (CH} 2) 23 -OCO- (CH 2) 6 -COO- (CH 2) 23 -CH 3
Formula _{(3-3) CH 3 - (CH} 2) 19 -OCO- (CH 2) 6 -COO- (CH 2) 19 -CH 3

  As specific examples of the triester having a structure represented by the above general formula (4), for example, compounds having structures represented by the following formulas (4-1) to (4-6) may be exemplified. it can.

  As specific examples of the triester having a structure represented by the above general formula (5), for example, compounds having structures represented by the following formulas (5-1) to (5-6) may be exemplified. it can.

  As specific examples of the tetraester having a structure represented by the above general formula (6), for example, compounds having structures represented by the following formulas (6-1) to (6-5) may be exemplified. it can.

Among the above, the ester is preferably a monoester.
Further, the ester wax constituting the first release agent component may have a structure in which a plurality of monoester structure, diester structure, triester structure and tetraester structure are held in one molecule.
Moreover, as a 1st mold release agent component which comprises a mold release agent, it can also be used combining 2 or more types of the above ester.

(Second mold release component)
The second release agent component according to the present invention contains at least microcrystalline wax.
Here, microcrystalline wax is a petroleum hydrocarbon, which differs from paraffin wax whose main component is linear hydrocarbon (normal paraffin), and in addition to linear hydrocarbon, branched hydrocarbon (iso paraffin) Or wax containing a large amount of cyclic hydrocarbon (cycloparaffin). Generally, microcrystalline wax is smaller in crystal size than paraffin wax because it contains a large amount of low crystalline isoparaffin and cycloparaffin. It has a larger molecular weight than wax.

Such microcrystalline wax has a carbon number of 30 to 60, a weight average molecular weight of 500 to 800, and a melting point of 60 to 90 ° C. The microcrystalline wax preferably has a weight average molecular weight in the range of 600 to 800 and a melting point in the range of 60 to 85 ° C. In addition, low molecular weight ones having a number average molecular weight within a range of 300 to 1000 are preferable, and ones within a range of 400 to 800 are more preferable.
Moreover, it is preferable that ratio (Mw / Mn) of a weight average molecular weight and a number average molecular weight exists in the range of 1.01-1.20.

  As microcrystalline wax, for example, HNP-0190, Hi-Mic-1045, Hi-Mic-1070, Hi-Mic-1080, Hi-Mic-1090, Hi-Mic-2045, manufactured by Nippon Seiwa Co., Ltd. Examples thereof include microcrystalline waxes such as Hi-Mic-2065 and Hi-Mic-2095, and waxes EMW-0001 and EMW-0003 whose main component is isoparaffin.

The microcrystalline wax preferably has a branching ratio in the range of 0.1 to 20%, and more preferably in the range of 0.3 to 10%.
The ratio of branching, ie, the ratio of the sum of tertiary carbon atoms to quaternary carbon atoms in all carbon atoms constituting microcrystalline wax, is in the range of 0.1 to 20%, so that microcrystalline wax is low. In spite of the melting point, entanglement between molecules due to the interaction with the ester wax is surely obtained, and the transfer of the release agent to the surface of the toner base particle hardly occurs.

Specifically, the ratio of branching in microcrystalline wax can be calculated by the following formula (i) from the spectrum obtained by the ¹³ C-NMR measurement method under the following conditions.
Formula (i): branch ratio (%) = (C3 + C4) / (C1 + C2 + C3 + C4) × 100
(In the formula (i), C1 is a peak area for a primary carbon atom, C2 is a peak area for a secondary carbon atom, C3 is a peak area for a tertiary carbon atom, and C4 is a peak area for a quaternary carbon atom Represents
(Conditions of the ¹³ C-NMR measurement method)
Measuring apparatus: FT NMR apparatus Lambda 400 (manufactured by Nippon Denshi Co., Ltd.)
Measurement frequency: 100.5 MHz
Pulse condition: 4.0 μs
Data point: 32768
Delay time: 1.8 sec
Frequency range: 27100 Hz
Integration number: 20000 times Measurement temperature: 80 ° C
Solvent: Benzene-d6 / o-dichlorobenzene-d4 = 1/4 (v / v)
Sample concentration: 3% by mass
Sample tube: Diameter 5 mm
Measurement mode: ¹ H complete decoupling method

The content of the first release agent component is in the range of 40 to 98% by mass with respect to the entire release agent, and the content of the second release agent component is the release It is characterized by being in the range of 2 to 60% by mass with respect to the entire agent.
Moreover, about the preferable range of content of a 1st mold release agent component and a 2nd mold release agent component, it is as having mentioned above. Furthermore, the content of the releasing agent is in the range of 5.0 to 12.5% by mass with respect to the toner base particles, which is excellent in the diselectrification effect, and the charging characteristics of the toner and the heat resistant storage stability Preferred in terms of

  The melting point of the releasing agent is preferably in the range of 50 to 95 ° C. from the viewpoint of the low temperature fixing property and the releasing property of the toner in the electrophotographic system.

«Binder resin»
The toner base particles according to the present invention preferably contain a crystalline polyester resin as a binder resin. By incorporating the crystalline polyester resin in the toner base particles, the crystalline polyester resin dispersed in the toner layer acts as a conductive path, and even in the case of an image of high coverage, charge removal is possible at a low voltage, and the toner layer Since the resistance of itself becomes low, it becomes difficult to be recharged, and the charge removal effect is excellent.
In addition to the crystalline polyester resin, it is preferable to contain an amorphous resin. The toner base particles may further contain other toner components such as a releasing agent (wax), a colorant, and a charge control agent, as necessary.
In the present invention, toner base particles to which an external additive is added are called toner particles, and an aggregate of toner particles is called toner. Generally, toner base particles can be used as toner particles as they are, but in the present invention, toner base particles to which an external additive is added are used as toner particles.
The components constituting the toner base particles will be described below.

A preferred embodiment of the present invention is a hybrid crystalline polyester resin in which a crystalline polyester resin is chemically bonded to a crystalline polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene.
The non-crystalline resin is a hybrid non-crystalline polyester resin in which the non-crystalline polyester polymer segment and the vinyl polymer segment having a structural unit derived from styrene are chemically bonded.

  In one embodiment of the present invention, toner base particles have a core-shell structure having a core portion containing a styrene resin and a crystalline polyester resin, and a shell portion containing a styrene resin. With such a structure, the heat resistant storage stability and the low temperature fixability are secured, and the control becomes easy so that the peak height ratio W falls within the above preferable range.

  Moreover, it is preferable that the styrene resin which forms a core part is a multilayer resin particle containing multiple layers. By forming a plurality of layers, the wax can be contained in the inner layer which is not the outermost layer, and by suppressing the exposure of the wax to the surface, it is possible to suppress the decrease in heat resistant storage stability. Here, the number of layers in the multilayer structure is not particularly limited, but in consideration of productivity and effects, it is preferably 2 to 5 layers, and more preferably 2 to 3 layers. .

  The shell portion may not cover the entire surface of the core portion, and the core portion may be partially exposed. The cross section of the core-shell structure can be confirmed by a known observation means such as, for example, a transmission electron microscope (TEM) or a scanning probe microscope (SPM).

  In the case of the core-shell structure, characteristics such as the glass transition temperature, the melting point and the hardness can be made different between the core portion and the shell portion, and the toner base particle can be designed according to the purpose. For example, a resin having a relatively high glass transition temperature (Tg) is coagulated and fused to the surface of the core portion containing a binder resin, a coloring agent, a releasing agent, etc. and having a relatively low glass transition temperature (Tg) Can form a shell portion.

  In addition, it is known that the crystalline polyester resin and the wax are contained in the core by a known observation means such as a transmission electron microscope (TEM) or a scanning probe microscope (SPM). , Can be confirmed.

«Crystalline polyester resin»
The toner base particles preferably contain a crystalline polyester resin as a binder resin. Therefore, at the time of heat fixing, the crystalline polyester resin and the non-crystalline resin are compatible with each other, and the low temperature fixing property of the toner can be improved, and the charge elimination effect of the image can be enhanced.

  "Crystalline polyester resin" refers to a known polyester obtained by the polycondensation reaction of a divalent or higher carboxylic acid (polyvalent carboxylic acid) and its derivative with a divalent or higher alcohol (polyhydric alcohol) and its derivative Among resins, in differential scanning calorimetry (DSC), it refers to a resin having not a stepwise endothermic change but a clear endothermic peak. A clear endothermic peak specifically means a peak whose half-width of the endothermic peak is within 15 ° C. when measured at a heating rate of 10 ° C./min in differential scanning calorimetry (DSC) Do.

  Differential scanning calorimetry (DSC) can be measured, for example, using a differential scanning calorimeter "diamond DSC" (manufactured by Perkin Elmer). In the measurement, the temperature is raised from room temperature (25 ° C.) to 150 ° C. at a lifting rate of 10 ° C./min, and isothermally held at 150 ° C. for 5 minutes. The measurement conditions (temperature rise and cooling conditions) are sequentially subjected to a cooling process of cooling to 0 ° C. for 5 minutes and a second heating process of raising the temperature from 0 ° C. to 150 ° C. at an elevation speed of 10 ° C./min. Do by). The above measurement is performed by enclosing 3.0 mg of a sample in an aluminum pan and setting it in a sample holder of a differential scanning calorimeter "diamond DSC". Use an empty aluminum pan as a reference.

  In the measurement, analysis is performed from the endothermic curve obtained in the first temperature rising process, and the top temperature of the endothermic peak derived from the crystalline polyester resin is taken as the melting point of the crystalline polyester resin.

  Examples of polyvalent carboxylic acid derivatives include alkyl esters of polyvalent carboxylic acids, acid anhydrides and acid chlorides. Examples of polyvalent alcohol derivatives include esters of polyvalent alcohols and hydroxycarboxylic acids.

The polyvalent carboxylic acid is a compound having two or more carboxy groups in one molecule.
Among them, a divalent carboxylic acid is a compound having two carboxy groups in one molecule, and examples thereof include oxalic acid, malonic acid, succinic acid, adipic acid, pimelic acid, sebacic acid, azelaic acid and n-dodecyl. Succinic acid, 1,9-nonane dicarboxylic acid, 1,10-decanedicarboxylic acid (dodecanedioic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid (tetradecanedioic acid), 1,13-trile Saturated aliphatic dicarboxylic acids such as decanedicarboxylic acid and 1,14-tetradecanedicarboxylic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid and itaconic acid; Examples thereof include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid.
Moreover, as polyvalent carboxylic acids other than bivalent carboxylic acid, trivalent or more polyvalent carboxylic acids, such as trimellitic acid and pyromellitic acid, can be mentioned, for example. Moreover, as a derivative of polyhydric carboxylic acid, the anhydride of these carboxylic acid compounds or a C1-C3 alkyl ester etc. are mentioned. One of these may be used alone, or two or more of these may be used in combination.

The polyhydric alcohol is a compound having two or more hydroxy groups in one molecule.
Among these, a divalent polyol (diol) is a compound having two hydroxy groups in one molecule, and examples thereof include ethylene glycol, 1,2-propanediol, 1,3-propanediol, and 1,4-butane. Diol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol And aliphatic diols such as neopentyl glycol and 1,4-butenediol. Moreover, as polyols other than a dihydric polyol, trivalent or more polyhydric alcohols, such as glycerol, pentaerythritol, trimethylol propane, and sorbitol, etc. are mentioned. One of these may be used alone, or two or more of these may be used in combination.

  Further, depending on the valence of the polyvalent carboxylic acid, the valence of the polyvalent alcohol, etc., it may have partial branching or crosslinking.

The method for forming the crystalline polyester resin using the above-mentioned monomer is not particularly limited, and the polyvalent carboxylic acid and the polyhydric alcohol are polycondensed (esterified) using a known esterification catalyst. The resin can be formed.
As an esterification catalyst which can be used, aliphatic monocarboxylates such as titanium acetate, titanium propionate, titanium hexanoate and titanium octanoate, titanium oxalate, titanium succinate, titanium succinate, titanium maleate, titanium adipate, sebacic acid Aliphatic carboxylic acids such as titanium aliphatic dicarboxylic acid such as titanium, titanium hexane tricarboxylic acid, titanium aliphatic tricarboxylic acid such as isooctane tricarboxylic acid, titanium octane tetracarboxylic acid, titanium aliphatic polycarboxylic acid such as titanium decanetetracarboxylic acid, etc. Titanium acid, titanium aromatic monocarboxylates such as titanium benzoate, titanium phthalate, titanium terephthalate, titanium isophthalate, titanium naphthalenedicarboxylate, titanium biphenyldicarboxylate, titanium anthracenedicarboxylate, etc. Aromatic dicarboxylic acid titanium; Aromatic titanium tricarboxylate, such as titanium trimellitic acid, titanium naphthalene tricarboxylic acid, titanium aromatic tetracarboxylic acid such as titanium benzenetetracarboxylic acid, titanium naphthalene tetracarboxylic acid; and titanium aromatic carboxylic acid such as titanium Compounds, titanium compounds of aliphatic carboxylic acids and titanium compounds of aromatic carboxylic acids and alkali metal salts thereof, titanium halides such as dichlorotitanium, trichlorotitanium, tetrachlorotitanium and tetrabromotitanium, tetrabutoxytitanium (titanium compounds Tetrabutoxide), tetraoctoxytitanium, tetraalkoxytitanium such as tetrastearoxytitanium, titanium acetylacetonate, titanium diisopropoxide bis acetylacetonate, titanium triethanol Laminate-, and titanium-containing catalysts, such as.

The melting point (Tm) of the crystalline polyester resin is preferably in the range of 50 to 90 ° C., preferably in the range of 69 to 80 ° C., from the viewpoint of obtaining sufficient charge elimination effect of the image and heat resistant storage stability. Is more preferred. Moreover, it is especially preferable to exist in the range of 70-80 degreeC.
The melting point (Tm) of the crystalline polyester resin is a value measured by the method described in the examples.

  The weight average molecular weight (Mw) of the crystalline polyester resin is preferably in the range of 5000 to 50000, and more preferably in the range of 5000 to 30000, from the viewpoint of low temperature fixability and glossiness stability.

  The content of the crystalline polyester resin is preferably in the range of 1.0 to 30.0% by mass, and more preferably in the range of 3.0 to 25.0% by mass with respect to the toner mass. And particularly preferably in the range of 6.0 to 15.0% by mass. Within such a range, the charge removal effect is excellent, the low temperature fixability is excellent, and the density of the formed image is also improved.

  The crystalline polyester resin is also referred to as a crystalline polyester polymerized segment, and a vinyl polymerized segment having a structural unit derived from styrene (hereinafter, also referred to as “amorphous polymerized segment other than polyester resin” or simply “amorphous polymerized segment”. It is preferred that and) contain a hybrid crystalline polyester resin chemically bonded.

  By the presence of the non-crystalline polymerized segment, the affinity between the hybrid resin and the non-crystalline resin is improved, and the dispersibility of the hybrid resin in the toner is improved, thereby enhancing the charge elimination effect of the image. Can.

  The crystalline polyester polymerization segment is composed of the above-mentioned crystalline polyester resin, and thus the description thereof is omitted.

  The amorphous polymerized segment is a portion derived from an amorphous resin other than the crystalline polyester resin. The inclusion of the amorphous polymerized segment in the hybrid resin (and in the toner) is confirmed, for example, by identifying the chemical structure using NMR measurement and methylation reaction Py-GC / MS measurement. it can.

  In addition, the amorphous polymerized segment does not have a melting point and has a relatively high glass transition temperature (Tg) when differential scanning calorimetry (DSC) is performed on a resin having the same chemical structure and molecular weight as the unit. It is a polymerized segment. At this time, for a resin having the same chemical structure and molecular weight as that of the unit, the glass transition temperature (Tg1) in the first temperature rising process in DSC measurement is preferably in the range of 30 to 80 ° C., particularly 40 to It is preferable to be in the range of 65 ° C. In addition, a glass transition temperature (Tg1) can be measured by the method as described in an Example.

  The amorphous polymerized segment is not particularly limited as long as it is defined above. For example, for a resin having a structure in which other components are copolymerized in the main chain by an amorphous polymer segment, or a resin having a structure in which an amorphous polymer segment is copolymerized in a main chain consisting of other components If the toner to be contained has the above-described non-crystalline polymerized segment, the resin corresponds to a hybrid resin having the non-crystalline polymerized segment as referred to in the present invention.

  Although the resin component which comprises an amorphous polymerization segment in particular is not restrict | limited, For example, a vinyl polymerization segment, a urethane polymerization segment, a urea polymerization segment etc. are mentioned. Among them, a vinyl polymerized segment is preferred because it is easy to control the thermoplasticity.

  The vinyl polymer segment is not particularly limited as long as it is obtained by polymerizing a vinyl compound, but in consideration of the plasticity at the time of heat fixation, it is preferable to have a structural unit derived from styrene. That is, it is preferable that the crystalline polyester resin is a hybrid crystalline polyester resin in which a crystalline polyester polymerized segment and a vinyl polymerized segment having a structural unit derived from styrene are chemically bonded. Also, for the same reason, it is more preferable that the vinyl polymerized segment is a styrene / acrylic polymerized segment.

  Therefore, in the following, a styrene-acrylic polymerized segment as an amorphous polymerized segment will be described.

The styrene / acrylic polymerized segment is formed by addition polymerization of at least a styrene monomer and a (meth) acrylic acid ester monomer. The styrene monomer referred to here includes, in addition to styrene represented by the structural formula of CH ₂ CHCH—C ₆ H ₅ , one having a structure having a known side chain or a functional group in the styrene structure. In addition to the acrylic acid ester and methacrylic acid ester represented by CH ₂ CHCHCOOR (R is an alkyl group), the (meth) acrylic acid ester monomer referred to here is an acrylic acid ester derivative and methacrylic acid ester derivative. Etc. are contained in known structures such as side chains and functional groups.

  Specific examples of styrene monomer and (meth) acrylic acid ester monomer are shown below, but those usable for the formation of the styrene / acrylic polymer segment used in the present invention are limited to those shown below. It is not a thing.

  First, specific examples of the styrene monomer include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4- Dimethylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene and the like can be mentioned. These styrene monomers may be used alone or in combination of two or more.

  Moreover, as a specific example of the (meth) acrylic acid ester monomer, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate Acrylic acid ester monomers such as stearyl acrylate, lauryl acrylate and phenyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, Stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl Methacrylate, methacrylic acid ester monomers such as dimethylaminoethyl methacrylate.

  In the present specification, the term "(meth) acrylic acid ester monomer" is a generic term for "acrylic acid ester monomer" and "methacrylic acid ester monomer". "Methyl acrylate" is a generic term for "methyl acrylate" and "methyl methacrylate".

  These acrylic acid ester monomers or methacrylic acid ester monomers may be used alone or in combination of two or more. That is, to form a copolymer using a styrene monomer and two or more acrylic acid ester monomers, and using a styrene monomer and two or more methacrylic acid ester monomers to form a copolymer It is possible to form a united body, or to form a copolymer by using a styrene monomer and an acrylic acid ester monomer and a methacrylic acid ester monomer in combination.

  The content of the structural unit derived from styrene (monomer) in the amorphous polymerized segment is preferably in the range of 40 to 90% by mass with respect to the total amount of the amorphous polymerized segment. In addition, the content of the structural unit derived from the (meth) acrylic acid ester monomer in the amorphous polymerized segment is preferably in the range of 10 to 60% by mass with respect to the total amount of the amorphous polymerized segment. . By setting it as such a range, it becomes easy to control the plasticity of hybrid resin.

Furthermore, it is preferable that the amorphous polymerized segment be addition polymerized with a compound for chemically bonding to the crystalline polyester polymerized segment in addition to the styrene monomer and (meth) acrylic acid ester monomer. . Specifically, it is preferable to use a compound which is ester-bonded to a hydroxy group derived from polyhydric alcohol [-OH] or a polybasic carboxylic acid derived carboxy group [-COOH] contained in the crystalline polyester polymerization segment.
Therefore, the amorphous polymerized segment is addition-polymerizable with respect to the styrene monomer and the (meth) acrylic acid ester monomer, and has a carboxy group [-COOH] or a hydroxy group [-OH]. It is preferable to further polymerize the compound.

  Such compounds include, for example, compounds having a carboxy group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester; 2-hydroxy Ethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate And compounds having a hydroxy group such as polyethylene glycol mono (meth) acrylate.

  It is preferable that the content rate of the structural unit derived from the said compound in an amorphous polymerization segment is in the range of 0.5-20 mass% with respect to the whole quantity of an amorphous polymerization segment.

  The method for forming the styrene / acrylic polymer segment is not particularly limited, and examples thereof include methods of polymerizing monomers using known oil-soluble or water-soluble polymerization initiators. Specific examples of the oil-soluble polymerization initiator include an azo or diazo polymerization initiator and a peroxide polymerization initiator described below.

  As an azo or diazo polymerization initiator, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1) -Carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile and the like.

  Examples of peroxide polymerization initiators include benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4 -Dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4-t-butylperoxycyclohexyl) propane, tris- (t-butylperoxy) triazine and the like.

  In the case of forming resin particles by emulsion polymerization, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble radical polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and salts thereof, hydrogen peroxide and the like.

  The content of the non-crystalline polymerization segment is preferably 3% by mass or more and less than 15% by mass with respect to the total amount of the hybrid crystalline polyester resin. By setting it as the said range, sufficient crystallinity can be provided to hybrid resin.

«Method for producing hybrid crystalline polyester resin (hybrid resin)»
The method for producing the hybrid crystalline polyester resin is not particularly limited as long as it is a method capable of forming a polymer having a structure in which the crystalline polyester polymer segment and the non-crystalline polymer segment are chemically bonded. Absent. As a specific manufacturing method of a hybrid resin, the method shown below is mentioned, for example.

(1) Method of producing a hybrid resin by performing polymerization reaction in which an amorphous polymer segment is polymerized in advance and a crystalline polyester polymer segment is formed in the presence of the amorphous polymer segment In this method, first, The addition reaction of the monomers constituting the above-mentioned non-crystalline polymerization segment (preferably, a vinyl monomer such as a styrene monomer and a (meth) acrylate monomer) is carried out to form the non-crystalline polymerization segment .
Next, the polyvalent carboxylic acid and the polyvalent alcohol are subjected to a polymerization reaction in the presence of the non-crystalline polymerization segment to form a crystalline polyester polymerization segment. At this time, a hybrid resin is formed by causing a condensation reaction of a polyvalent carboxylic acid and a polyhydric alcohol, and causing an addition reaction of a polyvalent carboxylic acid or a polyhydric alcohol to an amorphous polymer segment.

  In the above-mentioned method, it is preferable to incorporate sites which allow these units to react with each other in the crystalline polyester polymerized segment or the amorphous polymerized segment. Specifically, at the time of formation of the amorphous polymerizing segment, in addition to the monomers constituting the amorphous polymerizing segment, the carboxy group [—COOH] or hydroxy group [—OH] remaining in the crystalline polyester polymer segment Also used are compounds having a site capable of reacting with and a site capable of reacting with an amorphous polymerization segment. That is, by reacting this compound with a carboxy group [-COOH] or a hydroxy group [-OH] in the crystalline polyester polymer segment, the crystalline polyester polymer segment may be chemically bonded to the amorphous polymer segment it can.

  Alternatively, a compound which is capable of reacting with a polyhydric alcohol or a polyvalent carboxylic acid upon formation of a crystalline polyester polymerization segment and has a site capable of reacting with an amorphous polymerization segment may be used.

  By using the above method, a hybrid resin having a structure (graft structure) in which a crystalline polyester polymerization segment is chemically bonded to an amorphous polymerization segment can be formed.

(2) Method of forming a crystalline polyester polymer segment and an amorphous polymer segment and combining them to produce a hybrid resin In this method, first, a polyvalent carboxylic acid and a polyvalent alcohol are condensed. React to form a crystalline polyester polymeric segment. Further, separately from the reaction system for forming the crystalline polyester polymerization segment, the above-mentioned monomers constituting the non-crystalline polymerization segment are polymerized to form the non-crystalline polymerization segment. At this time, it is preferable that the crystalline polyester polymerization segment and the non-crystalline polymerization segment incorporate portions that can react with each other. In addition, since the method of incorporating such a reactive site | part is as above-mentioned, the detailed description is abbreviate | omitted.

  Next, the crystalline polyester unit formed above is reacted with the amorphous polymerized segment to form a hybrid resin of a structure in which the crystalline polyester polymerized segment and the amorphous polymerized segment are chemically bonded. it can.

  In addition, when the above reactive portion is not incorporated into the crystalline polyester polymerized segment and the amorphous polymerized segment, a system is formed in which the crystalline polyester polymerized segment and the amorphous polymerized segment coexist, A method may be adopted in which a compound having a site capable of binding to the crystalline polyester polymer segment and the amorphous polymer segment is introduced. Then, a hybrid resin having a structure in which a crystalline polyester polymer segment and an amorphous polymer segment are chemically bonded can be formed via the compound.

(3) Method of producing a hybrid resin by performing a polymerization reaction in which a crystalline polyester polymerization segment is formed in advance and an amorphous polymerization segment is formed in the presence of the crystalline polyester polymerization segment The condensation reaction of polyvalent carboxylic acid and polyvalent alcohol is carried out to carry out polymerization to form a crystalline polyester polymer segment.
Next, in the presence of the crystalline polyester polymerization segment, the monomers constituting the amorphous polymerization segment are polymerized to form an amorphous polymerization segment. At this time, as in the case of the above (1), it is preferable that in the crystalline polyester polymerized segment or the non-crystalline polymerized segment, a site where these units can react with each other be incorporated. In addition, since the method of incorporating such a reactive site | part is as above-mentioned, the detailed description is abbreviate | omitted.

  By using the above method, a hybrid resin having a structure (graft structure) in which an amorphous polymer segment is chemically bonded to a crystalline polyester polymer segment can be formed.

  Among the formation methods (1) to (3), the method (1) facilitates formation of a hybrid resin having a structure in which a crystalline polyester resin chain is grafted to an amorphous resin chain, and the production process is simplified. It is preferable because it can be done. In the method of (1), since the amorphous polymer segment is formed in advance and then the crystalline polyester polymer segment is bonded, the orientation of the crystalline polyester polymer segment tends to be uniform.

«Amorphous resin»
The amorphous resin is used as a binder resin together with the crystalline polyester resin to constitute toner base particles. The inclusion of the non-crystalline resin as the binder resin provides an advantage that an appropriate fixing strength and image gloss can be obtained, and a good chargeability can be obtained even under a temperature and humidity fluctuation environment.

  The amorphous resin is preferably 50% by mass or more, and more preferably 70 to 99% by mass, with respect to the entire binder resin. The content of the amorphous resin is preferably in the range of 65 to 95% by mass with respect to the total mass of the crystalline polyester resin, the amorphous resin, and the releasing agent, More preferably, it is in the range of 90% by mass. Within such a range, the low temperature fixability is excellent, and the density of the formed image is also improved.

  Here, the amorphous resin is a resin having no melting point and having a relatively high glass transition temperature (Tg) when differential scanning calorimetry (DSC) is performed. At this time, the glass transition temperature (Tg) is preferably in the range of 30 to 80 ° C., and particularly preferably in the range of 40 to 65 ° C. The glass transition temperature (Tg) can be measured by a differential scanning calorimeter (DSC), and specifically, it is measured by the method described in the examples. Those skilled in the art can control the glass transition temperature according to the composition of the resin.

  The weight average molecular weight (Mw) of the amorphous resin is not particularly limited, but is preferably in the range of 2,000 to 150,000, and more preferably in the range of 10,000 to 100,000.

As the amorphous resin, conventionally known amorphous resins in the technical field may be used. Among them, amorphous polyester resin or vinyl resin is preferable, and these resins may be mixed and used. Among them, the amorphous resin preferably contains a vinyl resin from the viewpoint of excellent environmental stability of the charge amount, preferably contains a styrene-based resin, and more preferably contains a styrene-acrylic resin. preferable.
Vinyl resins (especially styrene-acrylic resins) have less polar functional groups and lower hygroscopicity compared to amorphous polyester resins, so transferability is possible even under severe environments of high temperature and high humidity. Is good. Therefore, good transferability can be obtained under any environment. The content of the styrene-acrylic resin in the amorphous resin is not particularly limited. As described above, from the viewpoint of obtaining good transferability under any environment, the content of the styrene-acrylic resin is preferably in the range of 10 to 100% by mass with respect to the total amount of the amorphous resin. And more preferably in the range of 20 to 100% by mass.

Moreover, several types of amorphous resin may be mixed. As an example of non-crystalline resin other than a styrene acrylic resin, non-crystalline polyester resin or a hybrid non-crystalline polyester resin etc. are mentioned preferably. These amorphous resins are available by known synthetic methods or commercially available.
When the toner base particles have a core-shell structure, the styrene / acrylic resin and the crystalline polyester resin constitute the core from the viewpoint of controllability of the dispersion state of the crystalline polyester resin in the toner particles and charging characteristics. And the amorphous resin preferably constitutes the shell layer, the styrene / acrylic resin and the crystalline polyester resin constitute the core, and the amorphous polyester resin or the hybrid amorphous polyester resin constitutes the shell layer. It is more preferable that the styrene / acrylic resin and the crystalline polyester resin constitute the core portion, and the hybrid amorphous polyester resin constitute the shell layer.

<Styrene-based resin and styrene / acrylic resin (styrene / acrylic copolymer)>
In the present specification, a styrenic resin refers to one having at least a structural unit derived from styrene. The styrene resin is obtained by performing polymerization using at least a styrene monomer.

  Moreover, in this specification, a styrene acrylic resin represents what has a structural unit derived from a styrene, and a structural unit derived from a (meth) acrylic acid ester monomer at least. The styrene-acrylic resin is obtained by performing polymerization using at least a styrene monomer and a (meth) acrylic acid ester monomer.

  The styrene monomer and the (meth) acrylic acid ester monomer are the same as those described in the section of the styrene / acrylic polymer segment.

  The styrene-acrylic resin may have a structural unit derived from a general vinyl monomer, in addition to the structural unit derived from styrene and the structural unit derived from a (meth) acrylic acid ester monomer described above. Examples of usable vinyl monomers are shown below, but the present invention is not limited thereto.

(1) Olefins Ethylene, propylene, isobutylene etc. (2) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate etc. (3) Vinyl ethers Vinyl methyl ether, vinyl ethyl ether etc. (4) Vinyl ketones Vinyl methyl ketone, Vinyl ethyl ketone, vinyl hexyl ketone etc. (5) N-vinyl compounds N-vinylcarbazole, N-vinyl indole, N-vinyl pyrrolidone etc. (6) Others Vinyl compounds such as vinyl naphthalene, vinyl pyridine, acrylonitrile, methacryl oxide Nitrile, acrylic acid or methacrylic acid derivatives such as acrylamide, etc.

  In addition, vinyl monomers having a carboxy group can also be used. Specific examples thereof include vinyl monomers having a carboxy group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, and itaconic acid monoalkyl ester. Be Among these, acrylic acid or methacrylic acid is preferable.

  Furthermore, it is also possible to make a resin of a crosslinked structure using a multifunctional vinyl monomer.

  These vinyl monomers may be used alone or in combination of two or more.

  The content of the structural unit derived from styrene in the styrene / acrylic resin is not particularly limited, but is preferably in the range of 40 to 95% by mass, and more preferably in the range of 50 to 80% by mass with respect to the entire monomer. Moreover, the inside of the range of 5-60 mass% is preferable with respect to the whole monomer, and, as for content of the structural unit derived from a (meth) acrylic acid ester monomer, the inside of the range which is 20-50 mass% is more preferable.

  The molecular weight of the styrene-acrylic resin is preferably in the range of 2,000 to 1,000,000 in terms of weight average molecular weight (Mw). By setting the weight average molecular weight (Mw) of the styrene-acrylic resin in the above range, it is effective to suppress the occurrence of the offset phenomenon.

  The content of the styrene-acrylic resin in the binder resin is preferably in the range of 50 to 95% by mass from the viewpoint of achieving both suppression of temperature dependence of gloss and low-temperature fixability.

«Hybrid amorphous polyester resin»
In the toner of the present invention, the amorphous resin may contain a hybrid amorphous polyester resin in which an amorphous polyester polymerized segment and a vinyl polymerized segment having a structural unit derived from styrene are chemically bonded to each other. preferable.
More specifically, the amorphous resin is a hybrid amorphous polyester resin having a graft copolymer structure in which an amorphous polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene are chemically bonded to each other. It is preferable to contain By including such a hybrid amorphous polyester resin, the affinity of the shell to the vinyl resin is appropriately increased while maintaining the compatibility between the core and the shell. Therefore, the adhesion of the shell portion to the core portion becomes easier, and the heat resistant storage stability of the toner is further improved.

  The amorphous polyester polymerized segment is a portion derived from a known polyester resin obtained by the polycondensation reaction with the polyvalent carboxylic acid component and the polyhydric alcohol component similar to the amorphous polyester resin, and the differential scanning of the toner In the calorimetric measurement (DSC), it refers to a polymerization segment in which no clear endothermic peak is observed.

  Examples of the polyvalent carboxylic acid component include oxalic acid, succinic acid, maleic acid, adipic acid, 6-methyladipic acid, azelaic acid, sebacic acid, nonane dicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid , Fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelic acid, tartaric acid, mucic acid, phthalic acid , Isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylene diacetic acid, m-phenylene diglycolic acid, p-phenylene diglycolic acid, o-phenylene diglycolic acid , Diphenylacetic acid, diphenyl-p, p'- Carboxylic acids, naphthalene-1,4-dicarboxylic acids, naphthalene-1,5-dicarboxylic acids, naphthalene-2,6-dicarboxylic acids, anthracene dicarboxylic acids, dicarboxylic acids such as dodecenyl succinic acid; trimellitic acid, pyromellitic acid, naphthalene Examples thereof include tricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid and pyrenetetracarboxylic acid. These polyvalent carboxylic acids can be used alone or in combination of two or more. Among these, aliphatic unsaturated dicarboxylic acids such as fumaric acid, maleic acid and mesaconic acid, aromatic dicarboxylic acids such as isophthalic acid and terephthalic acid, succinic acid and trimellitic acid are preferably used.

  Moreover, as the polyhydric alcohol component, for example, ethylene glycol, propylene glycol, butanediol, diethylene glycol, hexanediol, cyclohexanediol, octanediol, decanediol, dodecanediol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct And dihydric alcohols such as glycerin, pentaerythritol, hexamethylolmelamine, hexaethylolmelamine, tetramethylolbenzoguanamine, tetraethylolbenzoguanamine and the like. These polyhydric alcohol components may be used alone or in combination of two or more. Among these, dihydric alcohols such as bisphenol A ethylene oxide adduct and bisphenol A propylene oxide adduct are preferable.

  The amorphous polyester polymerization segment is not particularly limited as long as it is as defined above. For example, a resin having a structure in which other components are copolymerized to the main chain by the amorphous polyester polymerization segment, and a resin having a structure in which the amorphous polyester polymerization segment is copolymerized to the main chain consisting of the other components If the toner containing the resin does not have a clear endothermic peak as described above, the resin corresponds to a hybrid non-crystalline polyester resin having a non-crystalline polyester polymerization segment in the present invention.

  The content of the amorphous polyester polymerization segment is preferably in the range of 75 to 98% by mass with respect to the total amount of the hybrid amorphous polyester resin. In addition, the component and content rate of each segment in a hybrid amorphous polyester resin can be specified by NMR measurement and a methylation reaction Py-GC / MS measurement, for example.

  The hybrid amorphous polyester resin contains, in addition to the above amorphous polyester polymerized segment, a vinyl polymerized segment containing a structural unit derived from styrene. The vinyl polymer segment is not particularly limited as long as it contains a structural unit derived from styrene, but in consideration of the plasticity at the time of heat fixing, a styrene- (meth) acrylate polymer segment (styrene / acrylic polymer segment) is preferable. .

  The styrene / acrylic polymerized segment is formed by addition polymerization of at least a styrene monomer and a (meth) acrylic acid ester monomer. Specific examples of the monomer capable of forming a styrene-acrylic polymer segment include the same monomers as those described for the above-mentioned styrene-acrylic resin, and therefore the description thereof is omitted here.

  It is preferable that the content rate of the structural unit derived from styrene in a vinyl polymerization segment is in the range of 40-95 mass% with respect to the whole quantity of a vinyl polymerization segment. Moreover, the content rate of the structural unit originating in the (meth) acrylic acid ester monomer in a vinyl polymerization segment has preferable inside of the range of 5-60 mass% with respect to the whole quantity of a vinyl polymerization segment.

  Furthermore, the vinyl polymer segment is preferably formed by addition polymerization of a compound for chemically bonding to the non-crystalline polyester polymer segment, in addition to the above-mentioned styrene monomer and (meth) acrylic acid ester monomer. Specifically, it is preferable to use a compound which is ester-bonded to a hydroxy group [-OH] derived from a polyhydric alcohol component or a carboxy group [-COOH] derived from a polyvalent carboxylic acid component, which is contained in the crystalline polyester polymerization segment. . Therefore, the vinyl polymer segment is capable of addition polymerization to styrene and (meth) acrylic acid ester monomers, and further polymerizing a compound having a carboxy group [-COOH] or a hydroxy group [-OH]. Is preferable.

  Such compounds include, for example, compounds having a carboxy group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester; 2-hydroxy Ethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate And compounds having a hydroxy group such as polyethylene glycol mono (meth) acrylate.

  The content of the constituent unit derived from the above compound in the vinyl polymer segment is preferably in the range of 0.5 to 20% by mass with respect to the total amount of the vinyl polymer segment.

  The method for forming the styrene / acrylic polymer segment is not particularly limited, and examples thereof include methods of polymerizing monomers using known oil-soluble or water-soluble polymerization initiators. Specific examples of the polymerization initiator are the same as those described in the section of the above-mentioned hybrid crystalline polyester resin.

  The content of the vinyl polymerized segment is preferably in the range of 2 to 25% by mass in the hybrid amorphous polyester resin.

  As a method of producing a hybrid amorphous polyester resin, the existing general scheme can be used. The following three can be mentioned as representative methods.

(1) A method of producing a hybrid non-crystalline polyester resin by carrying out a polymerization reaction in which a vinyl polymerized segment is polymerized in advance and an amorphous polyester polymerized segment is formed in the presence of the vinyl polymerized segment Of forming a reactive polyester polymer segment and a vinyl polymer segment and combining them to produce a hybrid amorphous polyester resin (3) Amorphous polyester polymer segment is polymerized in advance A method of producing a hybrid amorphous polyester resin by performing a polymerization reaction to form a vinyl polymer segment in the presence of a polyester polymer segment.

«Colorant»
The toner of the present invention preferably contains a colorant according to each color, if necessary.

  The content of each coloring agent is preferably in the range of 1 to 30 parts by mass, and more preferably in the range of 3 to 20 parts by mass with respect to 100 parts by mass of toner base particles. In addition, color reproducibility of the image can be secured in such a range.

  The types of colorants of each color will be described below.

As a coloring agent (pigment) used for toner (except CL), carbon black, magnetic substance, dye, pigment etc. can be used arbitrarily, and as carbon black, channel black, furnace black, acetylene black, thermal Black, lamp black, etc. are used.
Magnetic materials include ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys which do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, an alloy of the type called Heusler alloy such as manganese-copper-aluminum, manganese-copper-tin, chromium dioxide, etc. can be used.

  Examples of black colorants (pigments) used for the black toner (K) include carbon blacks such as furnace black, channel blacks, acetylene blacks, thermal blacks, lamp blacks, and magnetic powders such as magnetite and ferrite. .

  Examples of colorants (pigments) for magenta or red used in magenta toner (M) and the like include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48; 1, C.I. I. Pigment red 53; 1, C.I. I. Pigment red 57; 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 150, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 184, C.I. I. Pigment red 222, C.I. I. Pigment red 238 and the like.

  Further, as a colorant (pigment) for orange or yellow used for yellow toner (Y) etc., C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185 and the like.

  Further, as colorants (pigments) for green or cyan used for cyan toner (C) etc., C.I. I. Pigment blue 15, C.I. I. Pigment blue 15; 2, C.I. I. Pigment blue 15; 3, C.I. I. Pigment blue 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. Pigment green 7 and the like.

  As a white coloring agent (pigment) used for white toner (W), any of an inorganic pigment and an organic pigment can be used. Specifically, as white inorganic pigments, for example, heavy calcium carbonate, light calcium carbonate, titanium oxide (titanium dioxide), aluminum hydroxide, titanium white, talc, calcium sulfate, barium sulfate, zinc oxide, magnesium oxide And magnesium carbonate, amorphous silica, colloidal silica, white carbon, kaolin, calcined kaolin, delaminated kaolin, aluminosilicate, sericite, bentonite, smectite and the like. Examples of white organic pigments include polystyrene resin particles and urea formalin resin particles. Moreover, the white pigment which has hollow structure, for example, a hollow resin particle, hollow silica, etc. are mentioned. From the viewpoint of chargeability and hiding property, the white colorant (pigment) is preferably titanium oxide. As titanium oxide, any crystal structure such as anatase type, rutile type and brookite type can be used.

  The metallic colorant (pigment) used in the metallic toner (ME) means a material capable of obtaining a metallic tone, and it is not only a conductive metal material but also materials other than metal, and non-metal materials. It also includes a conductive material. As such a metallic coloring agent (pigment), an aluminum pigment (aluminum powder; aluminum or its alloy powder), a bronze powder, a pearl pigment etc. are mentioned.

  These colorants (pigments) can be used alone or in combination of two or more as needed.

  The size of the colorant (particles) is not particularly limited, but the median diameter on a volume basis is preferably in the range of 10 to 1000 nm, and more preferably in the range of 50 to 500 nm, It is particularly preferable to be in the range of 300 nm. Within such a range, high color reproducibility can be obtained, and it is preferable in that it is suitable for forming a small diameter toner necessary for high image quality. The volume-based median diameter of the colorant (particles) can be measured, for example, using Microtrac (registered trademark, the same applies hereinafter) particle size distribution measuring apparatus “UPA-150” (manufactured by Nikkiso Co., Ltd.).

«Charge control agent»
Each toner may contain other internal additives as required. Such internal additives include charge control agents. Examples of the charge control agent include metal complexes of salicylic acid derivatives with zinc and aluminum (salicylic acid metal complexes), calixarene compounds, organic boron compounds, and fluorine-containing quaternary ammonium salt compounds.

  The content ratio of the charge control agent is preferably in the range of usually 0.1 to 10 parts by mass and preferably in the range of 0.5 to 5 parts by mass with respect to 100 parts by mass of the binder resin in the toner. Is more preferred.

<< Form of Toner Base Particles >>
The toner base particles may have a so-called single-layer structure or a core-shell structure (a form in which a resin forming a shell layer on the surface of the core particles is aggregated and fused). It is also good. The toner (base) particle having a core / shell structure has a resin region (shell) having a relatively high glass transition temperature on the surface of the resin particle (core particle) having a relatively low glass transition temperature containing a coloring agent, a release agent, etc. It is preferable that it is a form which has a layer). The core-shell structure is not limited to the structure in which the shell layer completely covers the core particle, and for example, the shell layer does not completely cover the core particle, and the core particle is exposed in some places. Including those that exist.

  The form (the cross-sectional structure of the core-shell structure, etc.) of the toner base particles described above can be confirmed using a known means such as, for example, a transmission electron microscope (TEM) or a scanning probe microscope (SPM). is there.

«Average circularity of toner base particles»
From the viewpoint of improving low-temperature fixability, the average circularity of the toner base particles is preferably in the range of 0.92 to 1.000, and more preferably in the range of 0.940 to 0.995. .
Here, the said average circularity is the value measured using "FPIA-3000" (made by Sysmex). Specifically, the toner base particles are wetted with a surfactant aqueous solution, subjected to ultrasonic dispersion for 1 minute, and dispersed, then using “FPIA-3000” ”under the measurement condition HPF (high magnification imaging) mode, Measure with HPF detection number 4000 appropriate concentration. The roundness is calculated by the following equation.

Circularity = (perimeter of a circle with the same projected area as the particle image) / (perimeter of particle projection)
The mean circularity is an arithmetic mean value obtained by adding the circularity of each particle and dividing by the total number of particles measured.

«Particle diameter of toner base particle»
With respect to the particle diameter of the toner base particles, it is preferable that the volume-based median diameter (D ₅₀ ) is in the range of 3 to 10 μm. By setting the volume-based median diameter to the above range, reproducibility of fine lines and high image quality of photographic images can be achieved, and the amount of consumed toner can be reduced as compared with the case where large particle diameter toner is used. be able to. In addition, toner fluidity can be secured.
Here, the volume-based median diameter (D ₅₀ ) of the toner base particles is measured, for example, using an apparatus in which a computer system for data processing is connected to “Coulter Multisizer 3” (manufactured by Beckman Coulter, Inc.) It can be calculated.

  The volume-based median diameter of the toner base particles is controlled by the concentration of the coagulant, the amount of the solvent added in the aggregation / fusion step at the time of production of the toner described later, the fusion time, and the composition of the resin component. Can.

<External additive>
Each toner preferably contains known inorganic particles, particles such as organic particles, lubricants and the like as external additives from the viewpoint of improving charging performance, fluidity, or cleaning properties.
Various external additives may be used in combination. Examples of the particles include inorganic oxide particles such as silica particles, alumina particles and titania particles, inorganic stearic acid compound particles such as aluminum stearate particles and zinc stearate particles, strontium titanate particles, zinc titanate particles and the like. Inorganic titanic acid compound particles and the like.
Moreover, as a lubricant, salts of zinc, aluminum, copper, magnesium, calcium etc. of stearic acid, zinc of oleic acid, salts of manganese, iron, copper, magnesium etc., zinc of palmitic acid, copper, magnesium, calcium etc. And salts of higher fatty acids such as salts of zinc and calcium of linoleic acid and salts of zinc and calcium of ricinoleic acid.
These external additives may be surface-treated with a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil or the like from the viewpoint of heat resistance storage stability and environmental stability. The external additives may be used alone or in combination of two or more.

  Among the above, inorganic oxide particles such as silica particles (spherical silica), alumina particles and titania particles are preferably used as the external additive.

  The addition amount of the external additive (the total amount thereof when used in combination of two or more) is preferably in the range of 0.05 to 5% by mass, assuming that the total mass of the toner particles including the external additive is 100% by mass. More preferably, it is in the range of 0.1 to 3% by mass.

The particle diameter of the external additive is not particularly limited, but particles such as inorganic fine particles having a number average primary particle diameter of about 2 to 800 nm and organic fine particles having a number average primary particle diameter of about 10 to 2000 nm are preferable.
In the present specification, “number average primary particle diameter” refers to a value obtained by binarizing a scanning electron micrograph of external additive particles, calculating the horizontal Feret diameter for 10,000 particles, and taking the average. Say

[Method of producing toner]
The method for producing the toner is not particularly limited, and examples thereof include known methods such as a kneading and grinding method, a suspension polymerization method, an emulsion aggregation method, a dissolution suspension method, a polyester elongation method, and a dispersion polymerization method.

  Among these, from the viewpoint of controllability of the peak height ratio W, uniformity of particle diameter, shape controllability, and easiness of core / shell structure formation, it is preferable to adopt the emulsion aggregation method.

<Emulsification aggregation method>
In the emulsion aggregation method, a dispersion of binder resin particles (hereinafter, also referred to as "binder resin particles") dispersed by a surfactant or a dispersion stabilizer, and in some cases, as particles of a release agent (hereinafter, The particles are mixed with the dispersion liquid of the “releasing agent particles” or the particles of the coloring agent, are aggregated until the desired particle diameter is obtained, and the shape is controlled by performing fusion between the binder resin particles. And a method of producing toner base particles.

  Further, according to the emulsion aggregation method, toner base particles having a core-shell structure can also be obtained. Specifically, toner base particles having a core-shell structure are prepared by first using a binder resin particle for core particles and a colorant. Are coagulated (fused) to prepare core particles, and then binder resin particles for shell layer are added to the dispersion of core particles to form binder resin particles for shell layer on the surface of core particles. It can be obtained by forming a shell layer which covers the core particle surface by aggregating and fusing.

  In the case of producing the toner by the emulsion aggregation method, although not particularly limited, the following preferred embodiments may be mentioned.

  A method for producing a toner according to a preferred embodiment comprises the steps of preparing a crystalline polyester resin particle dispersion, a styrene-acrylic resin particle dispersion, and optionally a hybrid amorphous polyester resin particle dispersion (hereinafter also referred to as a preparation step) (A) A step of mixing a crystalline polyester resin particle dispersion and a styrene / acrylic resin particle dispersion and aggregating and fusing them to obtain a core particle dispersion (hereinafter also referred to as aggregation / fusion step) ( b) and a step (c) of mixing the core particle dispersion and the hybrid amorphous polyester resin particle dispersion, aggregating and fusing them to obtain a toner particle dispersion.

  Hereinafter, although each process (d)-(f) optionally performed other than each process (a)-(c) and these processes is explained in full detail, it is not restrict | limited to the following method.

(A) Preparation Step In the step (a), there is a step of preparing a crystalline polyester resin particle dispersion, a styrene / acrylic resin particle dispersion, and optionally a hybrid amorphous polyester resin particle dispersion, and Accordingly, a colorant dispersion preparation step and the like are included.

(A-1) Styrene-Acryl Resin Particle Dispersion Preparation Step The styrene-acryl resin particle dispersion is, for example, a method of performing dispersion treatment in an aqueous medium without using a solvent, or a styrene-acryl resin such as ethyl acetate. It is dissolved in a solvent to give a solution, and the solution is emulsified and dispersed in an aqueous medium using a dispersing machine, followed by solvent removal treatment, and the like. Preferably, a styrene acrylic resin is dispersed in an aqueous medium to prepare a styrene acrylic resin particle dispersion.

The aqueous medium refers to a medium having a water content of 50% by mass or more.
As components other than water, the organic solvent melt | dissolved in water is mentioned, For example, methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran etc. are mentioned. Among these, alcohol-based organic solvents such as methanol, ethanol, isopropanol, butanol and the like which are organic solvents which do not dissolve the resin are particularly preferable. Preferably, only water is used as the aqueous medium.

  Furthermore, in the aqueous medium, a dispersion stabilizer may be dissolved, and a surfactant, fine resin particles, etc. may be added for the purpose of improving the dispersion stability of the oil droplets.

  As the dispersion stabilizer, known ones can be used. For example, it is preferable to use ones that are soluble in acid or alkali such as tricalcium phosphate, or from the viewpoint of environmental aspect, by enzymes It is preferable to use a degradable one.

  As the surfactant, known anionic surfactants, cationic surfactants, nonionic surfactants and amphoteric surfactants can be used.

  Moreover, as resin fine particles for the improvement of dispersion stability, polymethyl methacrylate resin fine particles, polystyrene resin fine particles, polystyrene-acrylonitrile resin fine particles, etc. may be mentioned.

  The dispersion treatment is preferably carried out under stirring, and can be carried out using mechanical energy, and the dispersing machine is not particularly limited, and a homogenizer, a low speed shearing type dispersing machine, a high speed shearing type Dispersing machines, friction type dispersing machines, high pressure jet type dispersing machines, ultrasonic dispersing machines, high pressure impact type dispersing machines Altimizer, emulsification dispersing machines, etc. may be mentioned.

  The method for producing the styrene-acrylic resin is not particularly limited, and bulk polymerization method, solution polymerization method, emulsion polymerization method, mini-emulsion method, dispersion polymerization method, etc. using a known oil-soluble or water-soluble polymerization initiator Methods of carrying out the polymerization by known polymerization techniques may be mentioned. If necessary, known chain transfer agents such as n-octyl mercaptan may be used. Among them, it is preferable to use an emulsion polymerization method in which a resin monomer is added to an aqueous medium together with a polymerization initiator, and the monomer is subjected to a polymerization reaction to obtain a dispersion of resin particles.

In the emulsion polymerization method, the following seed polymerization is preferred. Specifically, a monomer (styrene monomer, (meth) acrylic acid ester monomer, etc.) for obtaining a styrene-acrylic resin is added to an aqueous medium together with a polymerization initiator and polymerized to obtain base particles. Get
Next, a radically polymerizable monomer and a polymerization initiator for obtaining a styrene-acrylic resin are added to the dispersion in which the resin particles are dispersed, and the radically polymerizable monomer is seeded to the above base particles. It is preferable to use a polymerization method.

Also, for example, when the polymerization reaction is performed in three steps, a dispersion of resin particles is prepared by the first stage polymerization, and a monomer of the resin and a polymerization initiator are further added to the dispersion, and the second stage polymerization is performed. Let
The resin monomer and the polymerization initiator are further added to the dispersion prepared by the second stage polymerization to perform the third stage polymerization. During the second and third stages of polymerization, the resin particles in the dispersion produced by the previous polymerization can be used as seeds to further polymerize the monomers newly added to the resin particles, It is possible to make the particle diameter and the like of resin particles uniform. In addition, by using different monomers in the polymerization reaction of each step, the structure of the resin particles can be made to have a multilayer structure, and it is easy to obtain resin particles having the desired characteristics.

At this stage, the releasing agent according to the present invention may be contained. In this case, in order to improve the dispersibility of the release agent (wax), the first and second release agent components and the polymerizable monomer (mixture) adjusted to the desired content are added to the aqueous medium After that, it is preferable to apply mechanical energy and stir, and it is preferable to use a homogenizer, a low speed shear disperser, a high speed shear disperser, a friction disperser, a high pressure jet disperser, an ultrasonic disperser, a high pressure impact disperser. It is preferable to use a dispersing machine such as a machine or an ultimizer.
A commercial item can also be used as a dispersing machine, for example, "CLEARMIX (registered trademark)" (M. Technics Co., Ltd. product), HJP30006 (made by Sugino Machine Co., Ltd.), ultrasonic homogenizer US-150T. (Made by Nippon Seiki Seisakusho) etc. can be used.

  At the time of dispersion, it is preferable to heat the solution. Although heating conditions are not specifically limited, Usually, it is about 60-100 degreeC.

(Polymerization initiator)
As a polymerization initiator which can be used for a polymerization reaction, a well-known thing can be used. For example, persulfates such as ammonium persulfate, sodium persulfate and potassium persulfate, 2,2'-azobis (2-aminodipropane) hydrochloride, 2,2'-azobis- (2-aminodipropane) nitrate, 4 And azo compounds such as 7, 7'-azobis-4-cyanovaleric acid and poly (tetraethylene glycol-2,2'-azobisisobutyrate); and peroxides such as hydrogen peroxide.

  Although the addition amount of the polymerization initiator varies depending on the target molecular weight and molecular weight distribution, specifically, it may be in the range of 0.1 to 5.0% by mass with respect to the addition amount of the polymerizable monomer. it can.

(Chain transfer agent)
During the polymerization reaction, a chain transfer agent can be added from the viewpoint of controlling the molecular weight of the resin particles. As a chain transfer agent which can be used, for example, as a chain transfer agent, mercaptan such as octyl mercaptan, dodecyl mercaptan, t-dodecyl mercaptan; n-octyl 3-mercapto propionate, stearyl 3-mercapto propionate, etc. Mercaptopropionic acid; and styrene dimer can be used. These can be used singly or in combination of two or more.

  Although the addition amount of a chain transfer agent changes with the target molecular weight and molecular weight distribution, it can be in the range of 0.1-5.0 mass% with respect to the addition amount of a polymerizable monomer.

(Surfactant)
In the polymerization reaction, a surfactant can be added from the viewpoint of preventing aggregation and the like of the resin particles in the dispersion liquid and maintaining a good dispersion state.

  As surfactant, for example, cationic surfactant such as dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, sodium stearate, sodium lauryl sulfate (sodium dodecyl sulfate), sodium polyoxyethylene dodecyl ether sulfate, sodium dodecyl benzene sulfonate etc A known surfactant such as an anionic surfactant of the following, or a nonionic surfactant such as dodecyl polyoxyethylene ether or hexadecyl polyoxyethylene ether can be used. One of these may be used alone or in combination of two or more.

The particle diameter of the styrene-acrylic resin particles (oil droplets) in the styrene-acrylic resin particle dispersion prepared in this manner is preferably in the range of 60 to 1000 nm as a volume-based median diameter, and in the range of 80 to 500 nm It is more preferable that
In addition, the median diameter of this volume reference | standard is measured by the method as described in an Example. The volume-based median diameter of the oil droplets can be controlled by the magnitude of mechanical energy at the time of emulsification and dispersion.

(A-2) Crystalline polyester resin particle dispersion preparation process As a method of dispersing crystalline polyester resin in an aqueous medium, the crystalline polyester resin is dissolved or dispersed in an organic solvent (solvent) to obtain an oil phase liquid And the oil phase liquid is dispersed in an aqueous medium by phase inversion emulsification or the like to form oil droplets in a controlled state at a desired particle size, and then the organic solvent is removed.

  As the organic solvent (solvent) used for preparation of the oil phase liquid, those having a low boiling point and low water solubility are preferable from the viewpoint of easy removal treatment after formation of oil droplets, For example, methyl acetate, ethyl acetate, methyl ethyl ketone, isopropyl alcohol, methyl isobutyl ketone, toluene, xylene and the like can be mentioned. These can be used singly or in combination of two or more.

  The use amount of the organic solvent (solvent) (the total use amount when two or more kinds are used) is preferably in the range of 1 to 600 parts by mass, more preferably 10 to 500 parts by mass with respect to 100 parts by mass of the resin Within the scope of

  Furthermore, in the oil phase liquid, ammonia, sodium hydroxide or the like may be added in order to ion dissociate the carboxy group and stably emulsify in the aqueous phase to smoothly emulsify.

  The use amount of the aqueous medium is preferably in the range of 50 to 2000 parts by mass, and more preferably in the range of 100 to 1000 parts by mass with respect to 100 parts by mass of the oil phase liquid. By setting the amount of the aqueous medium to be in the above range, the oil phase liquid can be emulsified and dispersed to a desired particle size in the aqueous medium.

  In the aqueous medium, a dispersion stabilizer may be dissolved, and a surfactant, fine resin particles, etc. may be added for the purpose of improving the dispersion stability of oil droplets. Specific examples and preferable examples of the dispersion stabilizer, the surfactant and the resin fine particles are as described in the section (a-1) above.

  Such emulsifying and dispersing of the oil phase liquid can be carried out using mechanical energy, and a dispersing machine for emulsifying and dispersing is not particularly limited, and a low speed shearing type dispersing machine, high speed shearing Examples of the disperser include a friction disperser, a friction disperser, a high pressure jet disperser, an ultrasonic disperser such as an ultrasonic homogenizer, and a high pressure impact disperser Ultimizer.

  The removal of the organic solvent after the formation of the oil droplets is carried out by gradually raising the temperature of the entire dispersion in a state in which the crystalline polyester resin particles / non-crystalline resin particles are dispersed in the aqueous medium under stirring, After giving strong stirring in the area, it can be carried out by an operation such as desolvation. Or it can remove, pressure-reducing using apparatuses, such as an evaporator.

  The average particle diameter of the particles (oil droplets) of the crystalline polyester resin particles (oil droplets) in the crystalline polyester resin particle dispersion prepared in this manner is within the range of 60 to 1000 nm in terms of volume-based median diameter. Preferably, it is more preferably in the range of 80 to 500 nm. In addition, an average particle diameter is measured by the method as described in an Example. The average particle size of the oil droplets can be controlled by the magnitude of mechanical energy at the time of emulsification and dispersion.

(A-3) Hybrid Amorphous Polyester Resin Particle Dispersion Preparation Step The hybrid amorphous polyester resin particle dispersion preparation step synthesizes a hybrid amorphous polyester resin constituting toner particles, and this hybrid amorphous polyester resin In this step, the resin is dispersed in the form of fine particles in an aqueous medium to prepare a dispersion of hybrid amorphous polyester resin particles.

  The method for producing the hybrid amorphous polyester resin is as described above, and thus the details are omitted.

  The hybrid non-crystalline polyester resin particle dispersion is prepared by, for example, dissolving or dispersing the hybrid non-crystalline polyester resin in an organic solvent (solvent), by performing dispersion processing in an aqueous medium without using a solvent (A) Oil phase liquid is prepared, and the oil phase liquid is dispersed in an aqueous medium by phase inversion emulsification or the like to form oil droplets in a controlled state to a desired particle size, and then the organic solvent is removed ( B) and the like.

  The aqueous medium and the dispersing method in the method (a) are as described in the above (a-1). The details of the method (i) are as described in the above (a-2).

  The particle diameter of the hybrid non-crystalline polyester resin particles (oil droplets) in the hybrid non-crystalline polyester resin particle dispersion prepared in this manner is preferably in the range of 60 to 1000 nm in volume based median diameter, The range of 500 nm is more preferable. In addition, the median diameter of this volume reference | standard is measured by the method as described in an Example. The volume-based median diameter of the oil droplets can be controlled by the magnitude of mechanical energy at the time of emulsification and dispersion.

(A-4) Step of Preparing Colorant Particle Dispersion The colorant is dispersed in an aqueous medium to prepare a colorant particle dispersion.

  At the time of preparation of the colorant particle dispersion, in order to improve the dispersion stability of the colorant particles, the above-mentioned surfactant can be added. Moreover, the mechanical energy mentioned above can be utilized for distributed processing.

  The colorant particles in the dispersion preferably have a volume-based median diameter in the range of 10 to 300 nm, more preferably in the range of 100 to 200 nm, and still more preferably in the range of 100 to 150 nm. .

(B) Coagulation and fusion process The prepared styrene-acrylic resin particle dispersion and, if necessary, the colorant particle dispersion are mixed, and each particle of styrene-acrylic resin particles and colorant particles is contained in an aqueous medium. Aggregate Furthermore, after heating the mixed solution, each particle can be fused by adding a crystalline polyester resin particle dispersion, thereby forming core particles (core portion). At the time of aggregation and fusion, an aggregation agent having a critical aggregation concentration or more may be added, and the mixture may be heated to a temperature higher than the glass transition temperature (Tg) of the styrene / acrylic resin to promote aggregation and fusion.

  More specifically, after a styrene-acrylic resin particle dispersion and, if necessary, a colorant particle dispersion are mixed, a base such as an aqueous solution of sodium hydroxide or the like is added to the mixture in advance to impart aggregation. , PH is preferably adjusted in the range of 9-12.

  Then, it is preferable to add a colorant particle dispersion, if necessary, and to add an aggregating agent at 25 to 35 ° C. with stirring over 5 to 15 minutes. The amount of the coagulant used is preferably in the range of 5 to 20% by mass with respect to the total solid content of the binder resin particles and the colorant particles. The aggregating agent that can be used is not particularly limited, and examples thereof include alkali metal salts, metal salts such as Group 2 metal salts, and the like.

  Examples of metal salts include monovalent metal salts such as sodium chloride, potassium chloride and lithium chloride, divalent metal salts such as calcium chloride, magnesium chloride, copper sulfate and magnesium sulfate, and trivalent metals such as iron and aluminum. Salt etc. are mentioned. Among them, divalent metal salts are preferable because they can be aggregated in a smaller amount.

  In the aggregation step, it is preferable to minimize the standing time (time to start heating) to be left after addition of the coagulant as much as possible. That is, it is preferable to start heating the dispersion liquid for aggregation as soon as possible after adding the aggregating agent, and to heat it. The standing time is usually within 30 minutes (lower limit 0 minutes), preferably within 10 minutes.

  In addition, in the aggregation step, it is preferable to rapidly raise the temperature by heating after adding the coagulant, and the temperature rising rate is preferably 0.8 ° C./min or more. The upper limit of the temperature raising rate is not particularly limited, but is preferably 15 ° C./min or less from the viewpoint of suppressing the generation of coarse particles due to the progress of rapid fusion.

  The temperature at which the crystalline polyester resin dispersion is charged (the first-stage dispersion liquid charging temperature) is not particularly limited, but is preferably in the range of 70 to 90 ° C., preferably in the range of 75 to 85 ° C. It is more preferable that In addition, the particle diameter at the time of charging the crystalline polyester resin dispersion (the diameter of the first stage dispersion charged particle) is preferably before the start of particle diameter growth to 5.0 μm or less, and before the start of particle diameter growth More preferably, it is 4.5 μm or less.

  Furthermore, it is important to continue the fusion by holding the temperature for a certain period of time, preferably until the median diameter on a volume basis becomes 4.5 to 7.0 μm, after addition of the crystalline polyester resin dispersion. .

(C) A step of mixing the core particle dispersion and the hybrid amorphous polyester resin particle dispersion and coagulating and fusing them to obtain a toner particle dispersion Next, the aqueous phase of the hybrid amorphous polyester resin particles forming the shell portion The dispersion is further added, and the hybrid amorphous polyester resin forming the shell portion on the surface of the binder resin particles (core particles) obtained above is coagulated and fused. As a result, a binder resin having a core-shell structure is obtained (shelling process). Then, when the size of the aggregated particles reaches a target size, a salt such as a sodium chloride aqueous solution is added to stop aggregation. Thereafter, heat treatment of the reaction system may be further performed until the aggregation and fusion of the shell portion on the surface of the core particle are further strengthened and the shape of the particle becomes a desired shape (second ripening step). This second ripening step may be carried out until the average circularity of the toner particles having a core-shell structure falls within the desired average circularity (preferably within the above-mentioned preferred range).

  Thereby, the growth of particles (crystalline resin particles, styrene-acrylic resin particles, hybrid amorphous polyester resin, and, if necessary, aggregation of colorant particles) and fusion (disappearance of the interface between particles) This can be effectively advanced, and the durability of toner particles finally obtained can be improved.

  Also, instead of the hybrid amorphous polyester resin, a styrene acrylic resin may be used as the resin of the shell layer.

(D) Cooling Step This step is a step of cooling the dispersion of toner particles. As a condition of the cooling process, it is preferable to cool at a cooling rate of 1 to 20 ° C./min.
The specific method of the cooling treatment is not particularly limited, and a method of introducing a refrigerant from the outside of the reaction vessel for cooling, a method of directly injecting cold water into a reaction system, and the like may be exemplified. it can.

(E) Filtration / Washing Step In this step, the toner particles are separated from the cooled dispersion of toner particles by solid-liquid separation, and toner cake obtained by solid-liquid separation (flocculates toner particles in a wet state into a cake) Is a step of removing deposits such as surfactants and flocculants from the resulting aggregate) and washing.

  The solid-liquid separation is not particularly limited, and a centrifugal separation method, a vacuum filtration method using Nutsche, etc., a filtration method using a filter press, etc. can be used.

(F) Drying Step This step is a step of drying the washed toner cake, and can be carried out in accordance with the drying step in a generally known method of producing toner particles.

  Specifically, as a dryer used for drying the toner cake, a spray dryer, a vacuum freeze dryer, a vacuum dryer, etc. can be mentioned, and a stationary shelf dryer, a movable shelf dryer, a fluidized bed, etc. It is preferable to use a drier, a rotary drier, a stirring drier or the like.

(G) Additive Step of External Additive This step is a step which is performed as necessary when adding the external additive to the toner particles.

  As a mixing apparatus of an external additive, mechanical mixing apparatus, such as a Henschel mixer, a coffee mill, and a sample mill, can be used.

[Developer]
The toner of each color may be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer.
When the toner is used as a two-component developer, as the carrier, magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of those metals and metals such as aluminum and lead are used. In particular, ferrite particles are preferable.
Further, as the carrier, a coated carrier in which the surface of the magnetic particles is coated with a coating agent such as a resin, or a dispersion type carrier obtained by dispersing magnetic powder in a binder resin may be used.

  The volume average particle diameter of the carrier is preferably in the range of 20 to 100 μm, and more preferably in the range of 25 to 80 μm. The volume average particle size of the carrier can be measured typically by a laser diffraction type particle size distribution measuring apparatus "HELOS" (manufactured by Sympathic) equipped with a wet disperser.

  The two-component developer can be produced by mixing the above-described carrier and toner using a mixing device. As a mixing apparatus, a Henschel mixer, a Nauta mixer, V-type mixer etc. are mentioned, for example.

  The compounding amount of the toner at the time of producing the two-component developer according to the present invention is preferably in the range of 1 to 10% by mass with respect to 100% by mass in total of the carrier and the toner.

<Image recording medium>
The image recording medium (also referred to as recording material, recording paper, recording paper, etc.) used in the image forming method of the present invention may be a commonly used one. For example, known image forming methods using an image forming apparatus etc. It is not particularly limited as long as it holds the toner image formed by the above.
Usable image supports include, for example, plain paper from thin paper to heavy paper, high quality paper, art paper, coated printing paper such as coated paper, commercially available washi paper or postcard paper, OHP Plastic films, cloths, various resin materials used for so-called soft packaging, or resin films formed by molding them into a film, labels and the like.

EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
<Synthesis of Crystalline Polyester Resin [c1]>
In a reaction vessel equipped with a stirrer, a nitrogen introduction tube, a temperature sensor, and a rectification column, 315 parts by mass of tetradecanedioic acid and 252 parts by mass of 1,4-butanediol were placed. After replacing the inside of the reaction vessel with dry nitrogen gas, 0.1 parts by mass of titanium tetrabutoxide was added, and a polymerization reaction was performed for 8 hours while stirring at 180 ° C. in a nitrogen gas flow. Furthermore, 0.2 parts by mass of titanium tetrabutoxide was added, and the temperature was raised to 220 ° C., and a polymerization reaction was performed for 6 hours while stirring. Thereafter, the pressure in the reaction vessel was reduced to 10 mmHg (13.3 hPa), and the reaction was performed under reduced pressure for 1.5 hours to obtain a crystalline polyester resin [c1]. The obtained crystalline polyester resin [c1] had a weight average molecular weight of 22,000 and a melting point of 75 ° C.

<Synthesis of Hybrid Crystalline Polyester Resin [HB-c1]>
The following monomers for the styrene / acrylic polymerized segment and a radical polymerization initiator were placed in the dropping funnel.
Styrene 36.0 parts by mass n-butyl acrylate 13.0 parts by mass Acrylic acid 2.0 parts by mass Radical polymerization initiator (di-t-butyl peroxide) 7.0 parts by mass In addition, a raw material single of crystalline polyester polymerization segment The monomer was placed in a four-necked flask equipped with a nitrogen gas inlet tube, a dehydration tube, a stirrer and a thermocouple, and heated to dissolve at 170 ° C.
Then, under stirring, the raw material monomer of the styrene / acrylic polymer segment is dropped over 90 minutes, and after aging for 60 minutes, the pressure is reduced under pressure (8 kPa). The raw material monomer of the unreacted styrene acryl polymerization segment was removed by. The amount of the raw material monomer removed at this time was a very small amount relative to the raw material monomer charged as described above. Thereafter, 0.8 parts by mass of titanium tetrabutoxide (Ti (O-n-Bu) ₄ ) is added as a catalyst, the temperature is raised to 235 ° C., and under reduced pressure for 5 hours under normal pressure (101.3 kPa) The reaction was carried out at (8 kPa) for 1 hour.
Next, after cooling to 200 ° C., a hybrid crystalline polyester resin 4 was obtained by reacting for 1 hour under reduced pressure (20 kPa). The obtained hybrid crystalline polyester resin [HB-c1] had a weight average molecular weight of 24500 and a melting point of 75 ° C.

<Preparation of Crystalline Polyester Resin Particle Dispersion [C1]>
100 parts by mass of the crystalline polyester resin [c1] obtained above is dissolved in 400 parts by mass of ethyl acetate and mixed with 638 parts by mass of a 0.26% by mass aqueous solution of sodium dodecyl sulfate prepared beforehand. The While stirring the obtained mixed solution, ultrasonic dispersion treatment was performed using an ultrasonic homogenizer US-150T (manufactured by Nippon Seiki Co., Ltd.) at V-LEVEL 300 μA for 30 minutes.
Thereafter, while heated to 40 ° C., using a diaphragm vacuum pump V-700 (manufactured by BUCHI), ethyl acetate is completely removed while stirring under reduced pressure for 3 hours, and crystalline polyester resin particle dispersion liquid [ C1] was prepared. The crystalline polyester resin particles in the dispersion had a volume-based median diameter of 160 nm.

<Preparation of Hybrid Crystalline Polyester Resin Particle Dispersion [HB-C1]>
With regard to the hybrid crystalline polyester resin particles [HB-c1], a hybrid crystalline polyester resin particle dispersion [HB-C1] was prepared in the same manner as the preparation of the crystalline polyester resin particle dispersion [C1].

<Synthesis of Hybrid Amorphous Polyester Resin for Shell [HB-a]>
A mixed solution of a monomer of the following styrene / acrylic resin, a monomer having a substituent which reacts with any of the amorphous polyester resin and the styrene / acrylic resin, and a polymerization initiator was placed in the dropping funnel.
Styrene 80.0 parts by mass n-butyl acrylate 20.0 parts by mass Acrylic acid 10.0 parts by mass Di-t-butyl peroxide (polymerization initiator) 16.0 parts by mass In addition, a single amount of the following amorphous polyester resin The body was placed in a four-necked flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer and a thermocouple, and was heated to dissolve at 170 ° C.
Bisphenol A propylene oxide 2 mol adduct 285.7 parts by mass Terephthalic acid 66.9 parts by mass Fumaric acid 47.4 parts by mass With stirring, the mixed solution contained in the dropping funnel is dropped to a four-necked flask over 90 minutes. After aging for 60 minutes, unreacted monomers were removed under reduced pressure (8 kPa). Thereafter, 0.4 parts by mass of titanium tetrabutoxide (Ti (OBu) ₄ ) is added as an esterification catalyst, the temperature is raised to 235 ° C., and the pressure is further reduced under normal pressure (101.3 kPa) for 5 hours The reaction was carried out at 8 kPa) for 1 hour.
Then, the reaction solution was cooled to 200 ° C., reacted under reduced pressure (20 kPa), and then desolvated to obtain a hybrid non-crystalline polyester resin for shells [HB-a].
The weight average molecular weight of the hybrid amorphous polyester resin for shells [HB-a] obtained above was 25,000, and the glass transition temperature was 60.degree.

<Preparation of Hybrid Amorphous Polyester Resin Particle Dispersion for Shell [HB-A]>
100 parts by mass of the hybrid amorphous polyester resin for shells [HB-a] obtained above is dissolved in 400 parts by mass of ethyl acetate, and a 0.26% by mass sodium dodecyl sulfate solution prepared beforehand is prepared It mixed with 638 mass parts. While stirring the obtained mixed solution, ultrasonic dispersion treatment was performed using an ultrasonic homogenizer US-150T (manufactured by Nippon Seiki Co., Ltd.) at V-LEVEL 300 μA for 30 minutes.
After that, while heated to 40 ° C., using a diaphragm vacuum pump V-700 (manufactured by BUCHI), ethyl acetate is completely removed while stirring under reduced pressure for 3 hours, and the solid content is 13.5 mass. % Hybrid amorphous polyester resin particle dispersion [HB-A] was prepared. The shell-based hybrid amorphous polyester resin particles in the dispersion had a volume-based median diameter of 160 nm.

Preparation of Colorant Particle Dispersion
While stirring a solution prepared by adding 90 parts by mass of sodium dodecyl sulfate to 1600 parts by mass of ion exchange water, 420 parts by mass of “CI pigment blue 15: 3” was gradually added as a coloring agent. A colorant particle dispersion was prepared by dispersing using a stirring device CLEARMIX (manufactured by M. Technique, "CLEARMIX" is a registered trademark of the company). The colorant particles in the dispersion had a volume-based median diameter of 110 nm.

<Preparation of styrene-acrylic resin particle dispersion [SP1] for core>
(First stage polymerization)
4 parts by mass of sodium dodecyl sulfate and 3000 parts by mass of ion exchange water are charged in a reaction vessel equipped with an agitator, a temperature sensor, a cooling pipe and a nitrogen gas introduction device, and the internal temperature is stirred while stirring at 230 rpm under nitrogen stream. Was heated to 80.degree. After the temperature rise, a solution of 10 parts by mass of potassium persulfate dissolved in 200 parts by mass of ion-exchanged water was added, the liquid temperature was again raised to 80 ° C., and a mixed solution of the following monomers was dropped over 2 hours.
Styrene 570.0 parts by mass n-butyl acrylate 165.0 parts by mass Methacrylic acid 68.0 parts by mass After dropping of the above mixed solution, polymerization is carried out by heating and stirring at 80 ° C. for 2 hours, and styrene / acryl for core Resin particle dispersion [1-a] was prepared.

(Second stage polymerization)
A solution of 3 parts by mass of sodium polyoxyethylene (2) sodium dodecyl ether sulfate in 1210 parts by mass of ion-exchanged water is charged into a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introducing device and heated to 80 ° C. did. After heating, 60 parts by mass in terms of solid content of the styrene / acrylic resin particle dispersion [1-a] for core prepared by the first step polymerization, and the following monomers, a chain transfer agent and a release agent at 80 ° C. And the mixed solution dissolved in the above was added.
Styrene (St) 245.0 parts by mass 2-ethylhexyl acrylate (2EHA) 97.0 parts by mass Methacrylic acid (MAA) 30.0 parts by mass n-octyl-3-mercaptopropionate 4.0 parts by mass Behenyl behenate " WEP-3 "(manufactured by NOF Corporation: first release agent component) 166.6 parts by mass Microcrystalline wax" HNP 0190 "(manufactured by Nippon Seiwa Co., Ltd .: second release agent component)
3.4 parts by mass The mixing and dispersing treatment was performed for 1 hour by a mechanical dispersing machine CLEARMIX (registered trademark) (manufactured by M. Technics Co., Ltd.) having a circulation path to prepare a dispersion containing emulsified particles (oil droplets). . A solution of a polymerization initiator prepared by dissolving 5.2 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water and 1000 parts by mass of ion-exchanged water are added to this dispersion, and the system is heated at 84 ° C. for 1 hour The polymerization was carried out by heating and stirring over a period of time to prepare a core styrene-acrylic resin particle dispersion [1-b].

(Third stage polymerization)
A solution of 7 parts by mass of potassium persulfate in 130 parts by mass of ion-exchanged water was added to the core styrene-acrylic resin particle dispersion [1-b] obtained by the second stage polymerization. Furthermore, under the temperature condition of 82 ° C., a mixed solution of the following monomers and a chain transfer agent was dropped over 1 hour.
Styrene (St) 350 parts by mass Methyl methacrylate (MMA) 50 parts by mass Acrylic acid n-butyl (BA) 170 parts by mass Methacrylic acid (MAA) 35 parts by mass n-octyl-3-mercaptopropionate 8.0 parts by mass After completion of the dropwise addition, polymerization was carried out by heating and stirring for 2 hours, and then cooled to 28 ° C. to prepare a core styrene / acrylic resin particle dispersion [SP1]. The styrene-acrylic resin particles in the dispersion had a volume-based median diameter of 145 nm. The weight average molecular weight of the obtained styrene-acrylic resin was 35,000, and the glass transition temperature (Tg) was 37 ° C.

<Preparation of styrene / acrylic acid particle dispersion [SP2] to [SP18] for core>
In the preparation of the styrene / acrylic oil particle dispersion [SP1] for the core, types and parts by mass of the releasing agent (first releasing agent component and second releasing agent component) used in the second stage polymerization Similarly, styrene-acrylic resin particle dispersions [SP2] to [SP18] for cores were prepared in the same manner as described in the following Table I.

<Manufacture of Toner [1]>
In a reaction vessel equipped with a stirrer, a temperature sensor, and a cooling pipe, 480 parts by mass (solid content conversion) of the core styrene / acrylic oil particle dispersion [SP1] prepared above and 42 parts by mass of a colorant particle dispersion 500 parts by mass of ion-exchanged water was added, and a 5 mol / L aqueous solution of sodium hydroxide was added to adjust the pH to 10. Furthermore, a solution of 80 parts by mass of magnesium chloride hexahydrate dissolved in 80 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. while stirring. After standing for 3 minutes, the temperature was raised to 80 ° C. over 60 minutes. Thereafter, as a crystalline resin particle dispersion, 10 parts by mass (solid content conversion) of dodecyl diphenyl ether disulfonic acid sodium salt was mixed with 68 parts by mass (solid content conversion) of “Hybrid crystalline polyester resin dispersion liquid [HB-C1]” (solid content conversion) The solution was added over 10 minutes, and when the supernatant of the reaction solution became clear, the stirring speed was adjusted so that the growth rate of the particle size was 0.02 μm / min, and Coulter Multisizer 3 (Beckmann · When the volume-based median diameter measured by Coulter Inc. reached 5.8 μm, the stirring speed was adjusted to stop the growth of particle diameter.
Next, 68 parts by mass (in terms of solid content) of the hybrid amorphous polyester resin particle dispersion for shell [HB-A] (in terms of solid content) is added over 30 minutes, and when the supernatant of the reaction liquid becomes transparent, 80 parts of sodium chloride An aqueous solution in which parts were dissolved in 320 parts by mass of ion exchange water was added to stop the growth of the particle size.
Then, the temperature is raised and the mixture is stirred at 80 ° C., and the reaction solution is heated to 10 ° C. when the average circularity becomes 0.970 using a flow type particle image measuring apparatus “FPIA-3000” (manufactured by Sysmex Corporation). It cooled to 25 degreeC with the cooling rate of / min, and obtained the dispersion liquid of toner [1].
The resulting dispersion was subjected to solid-liquid separation, and the dewatered toner cake was re-dispersed in ion-exchanged water at 35 ° C., and the operation of solid-liquid separation was repeated three times to wash. After washing, the resultant was dried at 40 ° C. for 24 hours to obtain toner base particles [1] (median diameter 5.8 μm on a volume basis).
0.6 parts by mass of hydrophobic silica particles (number average primary particle size: 12 nm, degree of hydrophobicity: 68) and 100 parts by mass of the obtained toner base particles [1], hydrophobic titanium oxide particles (number average primary particle size : 20 nm, degree of hydrophobization: 63) 1.0 parts by mass and sol-gel silica (number average primary particle size: 110 nm, degree of hydrophobization: 63), 1.0 part by mass, and adding a Henschel mixer (Nippon Coke Kogyo Co., Ltd.) Made for 20 minutes at 32.degree. C. with a rotor peripheral speed of 35 mm / sec. After mixing, coarse particles were removed using a 45 μm sieve to obtain Toner [1].

<Production of Toners [2] to [8] and [10] to [20]
In the production of toner [1], types and contents of styrene-acrylic resin particle dispersion for core and crystalline polyester resin particle dispersion, and content of releasing agent were changed as described in Table II below. Similarly, toners [2] to [8] and [10] to [20] were obtained.

<Manufacture of Toner [9]>
In a reaction vessel equipped with a stirrer, a temperature sensor, and a cooling pipe, 480 parts by mass (solid content conversion) of the core styrene / acrylic resin particle dispersion [SP1] prepared above and 42 parts by mass of the colorant particle dispersion 500 parts by mass of ion-exchanged water was added, and a 5 mol / L aqueous solution of sodium hydroxide was added to adjust the pH to 10. Furthermore, a solution of 80 parts by mass of magnesium chloride hexahydrate dissolved in 80 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. while stirring. After standing for 3 minutes, the temperature was raised to 80 ° C. over 60 minutes.
Thereafter, the stirring speed is adjusted so that the growth rate of the particle size is 0.02 μm / min, and the volume-based median diameter measured by Coulter Multisizer 3 (manufactured by Beckman Coulter Co., Ltd.) becomes 5.8 μm. The stirring speed was adjusted to stop the grain size growth.
Next, 68 parts by mass (in terms of solid content) of the hybrid amorphous polyester resin particle dispersion for shell [HB-A] (in terms of solid content) is added over 30 minutes, and when the supernatant of the reaction liquid becomes transparent, 80 parts of sodium chloride An aqueous solution in which parts were dissolved in 320 parts by mass of ion exchange water was added to stop the growth of the particle size.
Then, the temperature is raised and the mixture is stirred at 80 ° C., and the reaction solution is heated to 10 ° C. when the average circularity becomes 0.970 using a flow type particle image measuring apparatus “FPIA-3000” (manufactured by Sysmex Corporation). It cooled to 25 degreeC with the cooling rate of / min, and obtained the dispersion liquid of toner [9].
The resulting dispersion was subjected to solid-liquid separation, and the dewatered toner cake was re-dispersed in ion-exchanged water at 35 ° C., and the operation of solid-liquid separation was repeated three times to wash. After washing, the resultant was dried at 40 ° C. for 24 hours to obtain toner base particles [9] (median diameter 5.8 μm on a volume basis).
0.6 parts by mass of hydrophobic silica particles (number average primary particle diameter: 12 nm, degree of hydrophobicity: 68) and 100 parts by mass of the obtained toner base particles [9], hydrophobic titanium oxide particles (number average primary particle diameter : 20 nm, degree of hydrophobization: 63) 1.0 parts by mass and sol-gel silica (number average primary particle size: 110 nm, degree of hydrophobization: 63), 1.0 part by mass, and adding a Henschel mixer (Nippon Coke Kogyo Co., Ltd.) Made for 20 minutes at 32.degree. C. with a rotor peripheral speed of 35 mm / sec. After mixing, coarse particles were removed using a 45 μm sieve, to obtain a toner [9].

<Production of Developer [1] to [20]>
A ferrite carrier having a volume average particle diameter of 60 μm coated with a silicone resin is mixed with each of the toners [1] to [20] obtained above so that the concentration of the toner is 6% by mass, and each developer [ 1 to 20 were produced.

  The melting point of the crystalline polyester resin, the glass transition temperature of the amorphous resin, the volume-based median diameter of resin particles and colorant particles, and the weight average molecular weight (Mw) of the resin were measured as follows. .

Melting Point (Tm) of Crystalline Polyester Resin and Glass Transition Temperature (Tg) of Amorphous Resin>
The melting point (Tm) of the crystalline polyester resin and the glass transition temperature (Tg) of the amorphous resin were obtained using a differential scanning calorimeter (DSC-60A manufactured by Shimadzu Corporation) in accordance with ASTM D3418. The temperature correction of the detection part of this device (DSC-60A) uses the melting point of indium and zinc, and the heat of fusion uses the heat of fusion of indium. For samples, use an aluminum pan, set an empty pan for control, raise the temperature at a heating rate of 10 ° C / min, hold for 5 minutes from room temperature to 150 ° C, use liquid nitrogen from 150 ° C to 0 ° C. The temperature was lowered at −10 ° C./min, held at 0 ° C. for 5 minutes, and the temperature was raised again from 0 ° C. to 200 ° C. at 10 ° C./min. The endothermic curve at the time of the second temperature rise was analyzed, the onset temperature was made Tg for the amorphous resin, and the peak top temperature of the endothermic peak was made the melting point for the crystalline polyester resin.

<Median-based median diameter of resin particles, colorant particles, etc.>
The volume-based median diameter of resin particles, colorant particles, release agents, etc. was measured by a laser diffraction / scattering type particle size distribution measuring apparatus (Microtrack particle size distribution measuring apparatus “UPA-150” (manufactured by Nikkiso Co., Ltd.)).

<Weight average molecular weight of resin (Mw)>
The weight average molecular weight (Mw) of each resin contained in the binder resin was measured by the following measurement method using gel permeation chromatography (GPC).

That is, using the apparatus “HLC-8220” (made by Tosoh Corp.) and the column “TSKguardcolumn + TSKgelSuperHZM-M3 series” (made by Tosoh Corp.), while maintaining the column temperature at 40 ° C., flow rate of tetrahydrofuran (THF) as a carrier solvent It flowed at 0.2 mL / min. The measurement sample was dissolved in tetrahydrofuran so as to have a concentration of 1 mg / mL under dissolution conditions of treatment with an ultrasonic disperser for 5 minutes at room temperature (25 ° C.). Next, the sample solution is treated with a membrane filter with a pore size of 0.2 μm to obtain a sample solution, and 10 μL of this sample solution is injected into the device together with the above carrier solvent, and detected and measured using a refractive index detector (RI detector) The molecular weight distribution of the sample was calculated using a calibration curve measured using monodispersed polystyrene standard particles. As a standard polystyrene sample for standard curve measurement, the molecular weight by Pressure Chemical company is 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1 Measure at least 10 standard polystyrene samples using 1 × 10 ⁵ , 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ samples, and use a calibration curve It was created. Moreover, the refractive index detector was used for the detector.

[Evaluation]
<Sticking force in images with different coverage>
The developer prepared above is loaded into the apparatus shown in FIGS. 1 and 2 and the half toner adhesion amount in the same plane is 10.5 g / m ² and the other half toner adhesion amount is 10.5 g / m ² The image was output on 20 sheets on both sides (A3, OK top coated paper (manufactured by Oji Paper Co., Ltd.)).
In Examples 1 to 18 and Comparative Examples 2 and 3, voltage application was performed by the charge adjustment device, and in Comparative Example 1, no voltage application was performed. The voltage application unit of the charge adjustment device is constant current controlled, applies a voltage controlled at a predetermined current value to the sheet, and applies a voltage so as to be 40 μA here.
500 sheets of A3 J paper were placed on the outputted paper bundle and left for 2 hours. Placed on a flat table, stuck the tape to the top of the top sheet and slowly slipped horizontally. At this time, the second lower sheet is fixed to the table so as not to move. The force required to slide the paper was measured with a spring only. This measurement was repeated in order from the top, and the average value of the force indicated by the spring was taken as the sticking force. It was considered as a practicable level when the sticking force is 1.2 N or less.

Each release agent component in Table I is as follows.
・ Behenyl behenate: "WEP-3" (made by NOF Corporation)
-Pentaerythritol tetrabehenate: "WEP-5" (manufactured by NOF Corporation)
Microcrystalline wax: "HNP 0190" (manufactured by Nippon Seiwa Co., Ltd.)
Microcrystalline wax: "Hi-Mic-1080" (manufactured by Nippon Seiwa Co., Ltd.)
Microcrystalline wax: "Hi-Mic-1090" (manufactured by Nippon Seiwa Co., Ltd.)

  From the above results, it can be seen that the releasing agent in the toner base particles contains a first releasing agent component containing an ester wax and a second releasing agent component containing a microcrystalline wax, and a first releasing agent. In the image forming method of the present invention using a toner containing a releasing agent in which the content of the mold agent component and the content of the second releasing agent component are within the range of the present invention, as compared with the comparative example, The sticking force of the paper was small and was at a practical level.

DESCRIPTION OF SYMBOLS 1 image forming system 2 image forming apparatus 3 charge adjusting device 4 stacker device 10 control unit 20 operation panel unit 30 image reading unit 40 image forming unit 50 fixing unit 60 sheet feeding unit 80 voltage applying unit 81, 82 conductive rubber roller 83 power supply 90 storage unit 100 paper 101 first side 102 second side 210A, 220A toner image W release agent

Claims (6)

An image forming method for forming an image by removing residual charge of an image on an image recording medium, comprising:
An image forming step of fixing a toner on the image recording medium to form a toner image;
And V. applying a voltage having a polarity opposite to that of the surface potential of the toner image by a voltage application unit.
The toner contains toner base particles and an external additive, and the toner base particles contain a release agent.
The releasing agent contains a first releasing agent component containing an ester wax and a second releasing agent component containing a microcrystalline wax.
The content of the first release agent component is in the range of 40 to 98% by mass with respect to the entire release agent, and
An image forming method, wherein the content of the second release agent component is in the range of 2 to 60% by mass with respect to the entire release agent.   The image forming method according to claim 1, wherein the content of the releasing agent is in the range of 5.0 to 12.5% by mass with respect to the toner base particles. The content of the first release agent component is in the range of 60 to 98% by mass with respect to the entire release agent, and
The image forming method according to claim 1, wherein the content of the second release agent component is in the range of 2 to 40% by mass with respect to the entire release agent. The content of the first release agent component is in the range of 80 to 98% by mass with respect to the entire release agent, and
The content of the said 2nd mold release agent component exists in the range of 2-20 mass% with respect to the said whole mold release agent, The any one of Claim 1 to 3 characterized by the above-mentioned Image formation method described   The image forming method according to any one of claims 1 to 4, wherein the toner base particles contain a crystalline polyester resin.   The image according to claim 5, wherein the crystalline polyester resin comprises a hybrid crystalline polyester resin in which a crystalline polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene are chemically bonded. Formation method.

Images