JP2005300610A - Image forming method and toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method by which images of high image quality can be outputted, even when the images are formed at a high speed, using a fixing method by which the starting time can be reduced, and an image with high transmittance can be formed, when the image is formed on an OHP film. <P>SOLUTION: An image is fixed, by using a heating and fixing device equipped with a rotating body; a counter member which has a rotation axis parallel to the rotating body and which is brought into press-contact with the rotating body forming a nip; a heating member which heats the rotating body on the surface portion, except the nip; and a temperature control means which controls the temperature of the rotating body heated by the heating member. A transfer material is inserted into the nip and held and carried, and an image is fixed, by using the heating and fixing apparatus to heat the transfer material by the rotating body; and the toner which contains at least a binder resin, a colorant and wax, and has an endothermic peak P1 in the range of 55 to 120°C, and an endothermic peak P2 present in the range of 55 to 120°C and at a temperature side higher than the endothermic peak P1 in a DSC curve, at the temperature rise measured by DSC (differential scanning calorimeter), is used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming method used in an electrophotographic method, an electrostatic recording method, a magnetic recording method, and a toner jet method, and a toner used in the image forming method.

  A conventional image forming method will be described by taking an image forming apparatus such as an electrophotographic copying machine, a printer, and a fax machine as an example. The image forming apparatus uses an appropriate image forming process means such as electrophotography, electrostatic recording, and magnetic recording in the image forming unit, and is made of a heat-meltable resin or the like by a direct method or an indirect (transfer) method. An unfixed toner image made of the toner (developer) is formed on the surface of the recording material. The unfixed toner image formed on the recording material is heat-fixed on the recording material surface by a fixing device, whereby a permanently fixed image is obtained on the recording material surface.

  Conventionally, examples of such a fixing device include a heat roller type and a film heating type. In the heat roller method, a rotating roller pair is formed by a fixing roller (heat roller) and a pressure roller. A heat source such as a halogen lamp is built in the fixing roller, and this fixing roller is heated to a predetermined fixing temperature and the temperature is adjusted. The fixing roller is not fixed as a heated material in the pressure nip portion (fixing nip portion) of the roller pair. This is a heating device that heats and fixes an unfixed toner image on the surface of a recording material by introducing a recording material on which a toner image has been formed and carried, and nipping and conveying the recording material.

  The film heating method is a heating device that uses a film with a small heat capacity instead of the heat roller, sandwiches and conveys the recording material between the film and the pressure roller, and heats the recording material with a heater disposed on the inner surface of the film. is there. The film heating method is used as an on-demand fixing device because the temperature rise time is short.

  On the other hand, in order to improve the pressure contact state between the heat roller or the film and the pressure roller in the fixing nip portion, the fixing roller or film may be covered with an elastic layer such as rubber. In the heating method from the fixing roller or the inner surface of the film, this elastic layer functions as a heat insulating layer, so that even in the film heating method, it is difficult to ensure the on-demand property because the temperature rise time is extended.

  A heat insulating coating layer such as an elastic layer or a release layer is provided on the surface of a rotating body (heat roller or film; hereinafter referred to as “heating rotating body”) for heating a recording material as a heated material. In the case of providing, an apparatus of a surface heating method for heating from the surface side of the heating rotating body has been devised (for example, see Patent Document 1). According to this type of device, since heat can be supplied to the heating rotator from the surface, the response to the lighting of the heater as a heating source is good, and even when a rotator covered with an elastic layer is used, the device startup time Can be shortened.

  Certainly, the surface heating method is effective for shortening the start-up time, and can cope with an image forming apparatus having a process speed of around 100 mm / s. However, when image formation is performed at a higher speed, for example, at a process speed of about 200 mm / s, sufficient heat and pressure cannot be applied to the toner, so that the toner adheres to the surface of the fixing roller (so-called offset phenomenon (offset on the low temperature side) ), Or a decrease in transparency when an image is formed on an overhead projector (OHP) film. Furthermore, there is a tendency that toner or the like attached to the fixing roller due to this offset adheres to the surface heating device and accumulates or is damaged.

Under such circumstances, technical development relating to heat and pressure fixing of toner is essential, and several measures have been proposed for these.

  In general, when image formation is performed at a higher speed, in order to solve the above-described problems, it is necessary to supply a larger amount of heat energy instantaneously at the same time as applying a higher pressing force than before. For this reason, the undesirable situation that the enlargement and complexity of the apparatus of a surface heating system are needed has arisen. From these viewpoints, the toner used in the image forming apparatus as described above preferably exhibits a high sharp melt property when heated, and attempts have been made to achieve a high sharp melt property by improving the binder of the toner. Yes. Such a toner is excellent not only in low-temperature fixability but also in color mixing at the time of full-color image formation, so that the color reproduction range of the obtained fixed image can be expanded.

  As other measures, many methods have been proposed for solving the above problems by adding a wax component such as polyethylene or polypropylene having a low molecular weight to the toner. However, in order to achieve a sufficient effect, it is necessary to add a large amount of the wax component as described above to the toner. In that case, filming on the photoreceptor or the surface of the toner carrier such as a carrier or sleeve New problems such as image degradation and image degradation. On the other hand, when the addition amount of the wax component is small, it is necessary to provide a device for supplying a slight amount of offset prevention liquid, or an auxiliary cleaning member such as a take-up type cleaning web or a cleaning pad. Arise. In particular, when an OHP film is used as a transfer material during full-color image formation, the transparency and haze (cloudiness) of the fixed image is increased due to high crystallization of the wax component and the difference in refractive index between the wax component and the binder resin. The problem of worsening price) remains unresolved.

In order to solve these problems, an attempt is made to improve the fixing property by adding two or more kinds of waxes to the toner (for example, see Patent Documents 2 to 7). However, it is difficult to improve various properties required of the toner by simply including a plurality of wax components in the toner, and matching with an image forming apparatus using a surface heating type apparatus is sufficient. It will not be a thing.
JP-A-10-133505 JP-A-10-268559 Japanese Patent Laid-Open No. 10-20541 JP-A-5-303232 Japanese Patent Laid-Open No. 10-268560 Japanese Unexamined Patent Publication No. 2000-3070 JP-A-8-50367

  An object of the present invention is to provide an image forming method that solves the problems of the related art. That is, it is an object of the present invention to provide an image forming method that uses a fixing method capable of shortening the start-up time and that can output an image with good image quality even when image formation is performed at a higher speed. . Another object of the present invention is to provide an image forming method capable of forming an image having high transmittance when formed on an OHP film, and a toner suitably used in such an image forming method.

As a result of intensive studies, the inventors of the present invention specified a characteristic of the endothermic peak in the DSC curve at the time of temperature rise measured by a differential scanning calorimeter (DSC) of the toner, so that the surface heating type apparatus was developed. The present invention has found that the fixing method used has extremely good fixing characteristics even when image formation is performed at a higher speed, and that the transmittance of an image formed on an OHP film can also be improved. Was completed.

That is, the present invention includes at least (a) a charging step for charging an image carrier for carrying an electrostatic latent image, and (b) an exposure step for forming an electrostatic latent image on the charged image carrier by exposure. (C) developing the electrostatic latent image with the toner carried on the surface of the toner carrier to form a toner image on the image carrier; (d) forming on the surface of the image carrier. A transfer step of transferring the toner image to the transfer material with or without an intermediate transfer member, and (e) a fixing step of fixing the toner image on the transfer material by heating. An image forming method comprising:
In the fixing step, a rotating member, a counter member having a rotating shaft parallel to the rotating member and forming a nip by being pressed against the rotating member, and the rotating member are heated at a surface portion other than the nip. A heating member, and a temperature control means for controlling the temperature of the rotating body heated by the heating member, wherein the transfer material is nipped and conveyed through the nip, and the transfer material is heated by the rotating body. A process of fixing using a fixing device,
The toner contains at least a binder resin, a colorant and a wax, and endothermic peaks P1 and 55 existing in a range of 55 to 120 ° C. in a DSC curve at the time of temperature rise measured by a differential scanning calorimeter (DSC). The present invention relates to an image forming method characterized by having an endothermic peak P2 that is in a range of 120 ° C. and exists on a higher temperature side than the endothermic peak P1.

The present invention also provides a toner for visualizing an electrostatic latent image formed on an image carrier,
(A) a charging step of charging an image carrier for carrying an electrostatic latent image, (b) an exposure step of forming an electrostatic latent image on the charged image carrier by exposure, (c) the electrostatic Developing the latent image with the toner carried on the surface of the toner carrying member to form a toner image on the image carrying member; and (d) intermediately forming the toner image formed on the surface of the image carrying member. A transfer step of transferring to a transfer material with or without a transfer body; and (e) a rotating body and a rotating shaft parallel to the rotating body and facing the rotating body to form a nip. A member, a heating member for heating the rotating body at a surface portion other than the nip, and temperature control means for controlling the temperature of the rotating body heated by the heating member, and transferring a transfer material to the nip. The heating constant is inserted and nipped and conveyed, and the transfer material is heated by the rotating body. The device, a fixing step of fixing onto the transfer material by heating the toner image on the transfer material is used in an image forming method having,
It contains at least a binder resin, a colorant and a wax, and has endothermic peaks P1 and 55-120 ° C. in the range of 55-120 ° C. in the DSC curve at the time of temperature rise measured by a differential scanning calorimeter (DSC). The present invention relates to a toner having an endothermic peak P2 that is in a range and is on a higher temperature side than the endothermic peak P1.

  According to the present invention, the rotating body, a counter member having a rotating shaft parallel to the rotating body and forming a nip in pressure contact with the rotating body, and the rotating body are heated at a surface portion other than the nip. And a temperature control means for controlling the temperature of the rotating body heated by the heating member. The transfer material is inserted into the nip, nipped and conveyed, and the transfer material is heated by the rotating body. The toner image is fixed on the transfer material using a heat fixing device, and toner having a specific peak in the DSC curve at the time of temperature rise measured by a differential scanning calorimeter (DSC) is used on the OHP film. Thus, it is possible to provide an image forming apparatus that can improve the transmittance of an image formed on the surface and can be well matched with a surface heating type fixing apparatus capable of shortening the start-up time.

The image forming method of the present invention includes at least (a) a charging step for charging an image carrier for carrying an electrostatic latent image, and (b) forming an electrostatic latent image on the charged image carrier by exposure. (C) a developing step of forming a toner image on the image carrier by developing the electrostatic latent image with toner carried on the surface of the toner carrier; and (d) a surface of the image carrier. A transfer step of transferring the formed toner image to a transfer material with or without an intermediate transfer member; and (e) a fixing step of heating the toner image on the transfer material to fix it on the transfer material. Have. In the present invention, the fixing step includes a rotating body, an opposing member having a rotating shaft parallel to the rotating body and forming a nip by being pressed against the rotating body, and the rotating body at a surface portion other than the nip. A heating member that includes a heating member that heats and a temperature control unit that controls the temperature of the rotating body heated by the heating member, and that the transfer material is nipped and conveyed through the nip, and the transfer material is heated by the rotating member. This is a process of fixing using an apparatus. Further, the toner of the present invention used for the image forming method of the present invention contains at least a binder resin, a colorant and a wax, and in a DSC curve at the time of temperature rise measured by a differential scanning calorimeter (DSC), An endothermic peak P1 existing in the range of 55 to 120 ° C. and an endothermic peak P2 in the range of 55 to 120 ° C. and higher than the endothermic peak P1 are included.

[Fixing device]
First, the fixing device used in the present invention will be described.
The fixing device used in the image forming apparatus of the present invention is a facing device in which a toner image on a transfer material has a rotating body, a rotating shaft parallel to the rotating body, and presses against the rotating body to form a nip. A transfer material that is a heated material in the nip, and a heating member that heats the rotating body at a surface portion other than the nip, and a temperature control unit that controls the temperature of the rotating body heated by the heating member. Is a device for fixing the toner image on the transfer material by heating the transfer material by a rotating body.

  FIG. 1 is a schematic cross-sectional view showing an example of a fixing device that can suitably realize the fixing step in the image forming method of the present invention. This fixing device is a surface heating type heating device, and is a fixing roller 1 as a rotating body for heating a recording material P as a transfer material, and an opposing member that presses against the fixing roller 1 to form a nip N1. The pressure roller 3, the surface heating unit 2 as a heating member provided in contact with a portion other than the nip N 1 on the surface of the fixing roller 1 in order to heat the fixing roller 1 from the surface, A temperature control unit including a temperature detecting element 5, a power feeding circuit 101, and a control circuit 100 is provided for controlling the surface heating unit so that the surface temperature becomes a desired value.

  The fixing roller 1 includes a cored bar 1a obtained by processing aluminum, stainless steel, or the like into a cylindrical shape or a hollow cylindrical shape, and a layer 1b made of, for example, silicone rubber or fluororubber having a thickness of 1 to 50 mm covering the outer periphery of the cored bar. This is an elastic roller. If necessary, as shown in FIG. 1c, the outer periphery is coated with a layer made of PFA resin (perfluoroalkyl vinyl ether copolymer resin), PTFE resin (tetrafluoroethylene resin), etc. having a thickness of 10 to 100 μm. May be.

  The pressure roller 3 includes a cored bar 3a similar to the fixing roller 1 and a layer 3b made of, for example, silicone rubber or fluorine rubber having a thickness of 1 to 50 mm, which covers the outer periphery of the cored bar 3a. An elastic roller having a rotation axis parallel to the rotation axis. Similarly to the fixing roller 1, the outer periphery of the pressure roller 3 may be covered with a layer 3c made of PFA resin, PTFE resin, or the like, if necessary. The pressure roller 3 is pressed against the fixing roller 1 with a pressing force in the range of 10 to 500 N as necessary, and forms a fixing nip N1 as a transfer material heating nip portion.

The surface heating unit 2 includes a heating means (heating source) 2b for heating the surface of the fixing roller 1, a heater holder 2c that supports the heating means 2b, and a heating film 2a that is rotatably fitted on the heater holder 2c. And a pressure stay 2d for bringing the heater holder 2c into pressure contact with the fixing roller via the heating film 2a. For example, a ceramic heater can be suitably used as the heating source 2b. The heating source 2b is supported and fixed by being fitted into a recess formed in the heater holder 2c, and heats the surface of the fixing roller 1. An endless belt-shaped (cylindrical) heating film 2 a is fitted around the heater holder 2 c so as to freely rotate, and rotates with the rotation of the fixing roller 1. The pressure stay 2d presses the heater holder 2c against the fixing roller 1 against the elasticity of the elastic layer 1b of the fixing roller 1, and presses the heater 2b against the fixing roller 1 via the heating film 2a. The heating nip N2 is formed.

  The cylindrical heating film 2a located between the fixing roller 1 and the heater holder 2c is a heat-resistant material composed of a single layer or a composite layer having a thickness of 20 to 900 μm from the viewpoint of heat resistance, ensuring strength, durability and low heat capacity. For example, polyimide, polyetherimide (PEI), polyethersulfone (PES), tetrafluoroethylene-perfluoroalkylvinylether copolymer resin (PFA), polyetheretherketone (PEEK). ), Polyparabanic acid (PPA); or a composite layer film thereof; at least the toner image contact surface side of the polyimide film is made of a fluororesin such as tetrafluoroethylene resin (PTFE), PAF, FEP, or a silicone resin. Conductives such as carbon black, graphite, conductive whiskers Those that have been formed a releasing coat layer formed by adding the like are preferable. In the present invention, the surface of the heating film may be further coated with a PFA resin or PTFE resin having a thickness of about 3 to 200 μm as necessary.

  The fixing roller 1 is driven to rotate in the clockwise direction indicated by the arrow shown in FIG. As the fixing roller 1 is driven to rotate, the pressure roller 3 is driven to rotate counterclockwise as indicated by the arrow due to friction generated in the fixing nip N1. Further, the heating film 2a of the surface heating unit 2 is driven to rotate counterclockwise as indicated by an arrow around the outer circumference of the heater holder 2c while the inner surface thereof is in close contact with the surface of the heater 2b due to friction generated in the heating nip N2.

  Further, the heating source 2b as the heating means of the surface heating unit 2 rapidly increases in temperature by being energized from the power supply circuit 101 to the energization heat generating resistance layer. Due to the heat generated by the heater 2b, the surface of the rotary fixing roller 1 is heated through the heating film 2a in the heating nip N2.

  In FIG. 1, a temperature detecting element 5 as a temperature detecting means is in contact with the back surface of the surface of the heating source 2b facing the heating film 2a. In the present invention, a temperature measuring resistor, a thermistor, or the like having a low heat capacity can be used as the temperature measuring element 5. Based on the detected temperature of the heating film 2a by the temperature measuring element 5, the control circuit 100 constituting the temperature control means controls the power supply state from the power supply circuit 101 to the heating source 2b so that the surface temperature of the fixing roller 1 is predetermined. Temperature control (temperature adjustment) is controlled to maintain the fixing temperature. In FIG. 1, the temperature measuring element 5 is provided so as to be in contact with the substantially central portion of the heating film 2a. However, the position of the temperature measuring element 5 may be set upstream or downstream of the position shown in FIG. 1 with respect to the rotation direction as long as the temperature of the heating film 2a can be measured. It can select suitably according to a property and a soaking zone.

  In addition, the surface heating unit 2 that heats the surface of the fixing roller 1 has a heating nip N2 in order to maintain a small error between the temperature of the surface of the fixing roller 1 in the heating nip N2 and the temperature of the fixing roller 1 in the nip N1. It is preferable to be installed in the vicinity of the upstream side of N1. The smaller the distance from the heating nip N2 to the nip N1, the better. However, this distance is appropriately determined in consideration of the mechanical structure of the fixing device.

As the fixing roller 1 is driven to rotate, the pressure roller 3 and the heating film 2a of the surface heating unit 2 are driven to rotate, and the heating source 2b of the surface heating unit 2 is energized so that the surface temperature of the fixing roller 1 is predetermined. The recording material P carrying the unfixed toner image t as a transfer material is introduced into the fixing nip N1 between the fixing roller 1 and the pressure roller 3 in a state in which the heating temperature is adjusted to the fixing temperature. The recording material P is in close contact with the outer surface of the fixing roller 1 and passes through the fixing nip N together with the fixing roller 1, and the toner image t is heated by heat conduction from the fixing roller 1 in the process of passing through the fixing nip. The toner image is heated and fixed. The recording material P that has passed through the fixing nip N1 is separated from the outer surface of the fixing roller 1 and conveyed on the recording material outlet side of the fixing nip N1.

  The fixing device of the present invention can exhibit extremely excellent performance from the viewpoint of shortening the startup time. However, for relatively high-speed image formation at a process speed of 200 mm / s, the temperature on the surface of the fixing roller tends to be lower than that of a normal fixing device, and the toner to the fixing roller and the surface heating unit is accompanied by a low temperature offset. Adhesion occurs and causes image deterioration during the fixing process. Further, since the transmittance when an image is fixed on the OHP (hereinafter referred to as “OHP transmittance”) tends to be lowered, the OHP projection image is also inferior. However, by using the toner described later, even when image formation is performed at a higher speed, the matching with the fixing device used in the present invention is also good, so that the toner adheres to the fixing roller and the surface heating unit. do not do. Furthermore, since the unfixed toner image t is heated and pressed in a good state on the recording material P and the surface of the image becomes smooth, when an OHP sheet is used as the recording material P, the transparency is also improved.

[toner]
Next, the toner of the present invention used for image formation of the present invention will be described.
The toner used in the present invention contains at least a binder resin, a colorant and a wax. The toner used in the present invention is composed of toner particles composed of the binder resin, colorant and wax, and external additives added to and mixed with the toner particles as necessary.

  The toner used in the present invention has an endothermic peak P1 and an endothermic peak P2 existing on the higher temperature side than the endothermic peak P1 in the range of 55 to 120 ° C. in the DSC curve at the time of temperature rise measured by DSC. It is characterized by. In the present invention, such endothermic peaks P1 and P2 are substantially derived from the wax contained in the toner. In this way, by using toner having two different peaks (derived from wax) in the range of 55 to 120 ° C. in the DSC curve, an image forming apparatus including the above-described surface heating type fixing device is used. For example, even when the image forming apparatus is operated at a high process speed such as 200 mm / s, the toner on the transfer material can be heated and pressed in a good state, thereby preventing offset on the low temperature side and fixing. Since it is possible to prevent the toner from sticking to the roller and the generation of scratches, a good image can be stably formed over a long period of time. In order to further exhibit such effects, the toner of the present invention preferably has peaks P1 and P2 in the range of 60 to 115 ° C. in the DSC curve, and peaks P1 and P2 in the range of 65 to 110 ° C. It is more preferable to have.

  The wax having the endothermic peak P1 has an effect of improving the fixing property on the low temperature side in order to cope with an increase in speed in the surface heating type fixing device. The position of the peak P1 derived from this wax in the DSC curve is not particularly limited as long as the temperature is in the range of 55 to 120 ° C and lower than the peak P2, but it is in the range of 60 to 100 ° C. Is preferable, and it is more preferable that it exists in the range of 65-90 degreeC. When the peak position of P1 is less than 55 ° C., an offset on the low temperature side tends to occur.

  Further, the wax having the endothermic peak P2 effectively acts to prevent the toner from adhering to the surface heating unit and the fixing roller and the occurrence of scratches in the fixing device. The position of the peak P2 derived from this wax in the DSC curve is not particularly limited as long as it is in the temperature range of 55 to 120 ° C. and on the lower temperature side than the peak P1, but is preferably in the range of 65 to 115 ° C., 70 More preferably, it is in the range of ˜110 ° C. When the peak position of P2 exceeds 120 ° C., the toner adheres to the surface heating unit or the fixing roller of the present invention, and scratches occur.

  The intensity ratio (P1 / P2) between the endothermic peaks P1 and P2 is preferably in the range of 0.1-10. The intensity ratio (P1 / P2) is more preferably 0.2 to 5. When the intensity ratio of the endothermic peak is less than 0.1, the effect of the wax showing the endothermic peak P1 cannot be sufficiently exerted, and the fixing property on the low temperature side is inferior and offset tends to occur. On the other hand, if the intensity ratio of the endothermic peak exceeds 10, the effect of the wax showing the endothermic peak P2 cannot be sufficiently exerted, and toner sticking to the surface heating unit or the fixing roller in the fixing device or damage tends to occur.

  In addition, as a method of adjusting the intensity ratio (P1 / P2) of the endothermic peaks P1 and P2 to the above range, for example, the amount of the wax showing the endothermic peak P1 and / or the wax showing the endothermic peak P2 when the toner is manufactured. The method of adjusting each is mentioned.

  For DSC measurement of the wax or toner in the present invention using a differential scanning calorimeter, for example, DSC-7 manufactured by Perkin Elmer or DSC-2920 manufactured by TA Instruments Japan can be used.

  In the present invention, the endothermic peak temperature of toner or wax is measured using DSC-2920 manufactured by TA Instruments Japan, and the endothermic peak temperature of the toner is obtained from the obtained DCS curve at the time of temperature increase. An aluminum pan is used as a measurement sample, and an empty pan is set as a control. From 20 ° C. to 180 ° C. at a rate of temperature rise of 2 ° C./min while applying an amplitude of ± 1.5 ° C. and a period of 1 / min. Raise the temperature.

  In the present invention, the height ΔH from the baseline to the peak top per unit mass using the DSC measurement method (value obtained by dividing the measured peak height by the mass of the measurement sample (mW / mg) ) Is the endothermic peak intensity.

  Even if the peaks P1 and P2 in the toner of the present invention are overlapped, it is only necessary that the peak top of each other can be confirmed. In this case, the endothermic peak intensity is calculated by defining ΔH as the peak top where each peak can be confirmed.

  The toner of the present invention preferably contains an ester wax and a hydrocarbon wax as the wax, and the endothermic peak P1 is a peak derived from the ester wax, and the endothermic peak P2 is preferably a peak derived from the hydrocarbon wax. The wax suitably contained in the toner of the present invention will be described below.

  The ester wax suitably used in the present invention preferably has a weight average molecular weight (Mw) of 350 to 1,500, and is preferably 450 to 1200, from the viewpoint of improving the low temperature fixability and OHP transmittance in the fixing device of the present invention. Are more preferred. When Mw is less than 350, it is difficult to maintain good fixability on the low temperature side, and when it exceeds 1500, the OHP transmittance tends to deteriorate.

  The following compounds are mentioned as a preferable ester compound which comprises ester wax.

［式中ａ及びｂは０〜４の整数であり、ａ＋ｂは４であり、Ｒ_１及びＲ_２は炭素数が１〜４０の整数を有する有機基であり、ｍ及びｎは０〜２５の整数であり、ｍとｎが同時に０になることはない。］

[Wherein a and b are integers of 0 to 4, a + b is 4, R ₁ and R ₂ are organic groups having an integer of 1 to 40 carbon atoms, and m and n are 0 to 25. It is an integer, and m and n are not 0 at the same time. ]

［式中、ａは０〜４の整数であり、ｂは１〜４の整数であり、ａ＋ｂは４であり、Ｒ_１は炭素数が１〜４０の整数を有する有機基であり、ｍ及びｎは０〜２５迄の整数であり、ｍとｎが同時に０になることはない。］

[Wherein, a is an integer of 0 to 4, b is an integer of 1 to 4, a + b is 4, R ₁ is an organic group having an integer of 1 to 40 carbon atoms, m and n is an integer from 0 to 25, and m and n are not 0 at the same time. ]

［式中、ａ及びｂは０〜３の整数であり、ａ＋ｂは１〜３であり、Ｒ_１及びＲ_２は炭素数が１〜４０の整数を有する有機基であり、Ｒ_１とＲ_２の炭素数の差が３以上であり、Ｒ_３は水素原子又は炭素数が１以上の有機基であり（但し、ａ＋ｂが２のとき、Ｒ_３のどちらか一方は、炭素数が１以上の有機基である）、ｋは１〜３の整数であり、ｍ及びｎは０〜２５の整数であり、ｍとｎが同時に０になることはない。］

[Wherein, a and b are integers of 0 to 3, a + b is 1 to 3, R ₁ and R ₂ are organic groups having an integer of 1 to 40 carbon atoms, R ₁ and R ₂ The difference in carbon number is 3 or more, and R ₃ is a hydrogen atom or an organic group having 1 or more carbon atoms (provided that when a + b is 2, either one of R ₃ has 1 or more carbon atoms) K is an integer of 1 to 3, m and n are integers of 0 to 25, and m and n are not 0 at the same time. ]

  Specific examples of such ester compounds used in the present invention are shown below.

  Examples of the method for producing the ester wax used in the present invention include a synthesis method by oxidation reaction, synthesis from carboxylic acid and its derivatives, ester group introduction reaction represented by Michael addition reaction, and the like. A particularly preferred method for producing the ester wax used in the present invention is a method using a dehydration condensation reaction from a carboxylic acid compound and an alcohol compound, or an acid halide and an alcohol compound, as shown below, because of the diversity of raw materials and the ease of reaction. The reaction from is particularly preferred.

［式中、Ｒ_３及びＲ_４は有機基を示す。］

[Wherein R ₃ and R _{4 each} represents an organic group. ]

  In order to transfer the above ester equilibrium reaction to the production system, the reaction is performed using a large excess of alcohol or a Dean-Stark water separator in an aromatic organic solvent capable of azeotropy with water. Is preferred. An ester may be synthesized by using an acid halogen compound and adding a base as an acceptor of an acid by-produced in an aromatic organic solvent.

  Next, the hydrocarbon wax that can be used in the toner used in the present invention will be described. The hydrocarbon wax that can be suitably used in the present invention has a weight average molecular weight (Mw) of 300 to 4000. When Mw is less than 300, the effect as a wax does not work sufficiently, and toner sticking to the surface heating unit or the fixing roller or damage is likely to occur. When Mw exceeds 4000, the OHP transmittance tends to deteriorate.

  The hydrocarbon wax used in the present invention preferably has a solubility in styrene at 25 ° C. of 5 to 60% by mass. When the solubility is less than 5% by mass, the dispersibility of the wax in the binder resin is deteriorated. For this reason, when an image is formed on an OHP sheet using the fixing device used in the present invention, crystals derived from hydrocarbon wax appear on the image surface fixed on the OHP sheet, and the image surface is smooth. Therefore, the OHP transmittance tends to deteriorate. Further, when the solubility exceeds 60% by mass, the hydrocarbon wax is excessively dissolved in the binder resin, so that the performance as the hydrocarbon wax cannot be sufficiently exhibited, and the surface heating unit of the fixing device used in the present invention. In addition, the toner may adhere to the fixing roller or may be damaged. The solubility in the present invention is calculated by adding a large excess of hydrocarbon wax to styrene at 25 ° C., stirring vigorously for 1 hour, filtering off the hydrocarbon wax that did not dissolve, and measuring the mass. To do.

  Examples of hydrocarbon waxes that can be used in the present invention include petroleum waxes such as paraffin wax, microcrystalline wax, petrolactam, and derivatives thereof; hydrocarbon waxes and derivatives thereof by the Fischer-Tropsch method; polyolefin waxes and derivatives thereof typified by polyethylene Derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. Also included are hardened castor oil and derivatives thereof, vegetable waxes and animal waxes. These can be used alone or in combination of two or more.

Among these, when the hydrocarbon wax by the Fischer-Tropsch method is used, the effect of improving the fixing property is further enhanced. These waxes may contain an antioxidant within a range that does not affect the chargeability of the toner. Moreover, it is preferable to use 0.5-30 mass parts of these waxes with respect to 100 mass parts of binder resin.

  In the present invention, when contained in the toner, an ester wax showing an endothermic peak P1 in the range of 55 to 120 ° C. in the DSC curve, and a hydrocarbon showing a peak P2 present on the higher temperature side than P1. By appropriately selecting and using the wax, the toner having the endothermic peaks P1 and P2 in the present invention can be obtained.

  The toner of the present invention preferably has an insoluble content in THF (tetrahydrofuran) of 0.1 to 40% by mass. When the THF-insoluble content is less than 0.1% by mass, the toner becomes too soft and toner adhesion to the fixing roller used in the present invention is likely to occur, and matching with the fixing device may be inferior. . On the other hand, if it exceeds 40% by mass, the toner becomes too hard, and even when the fixing device is used, the OHP transmittance tends to decrease when the process speed is faster, such as 200 mm / s.

  In the present invention, the THF insoluble content of the toner refers to the mass ratio of the resin component insoluble in THF (tetrahydrofuran) of the resin composition in the toner particles, and indicates the degree of crosslinking of the resin composition containing the crosslinking component. As a guideline, even if the THF-insoluble content is 0% by mass, it does not necessarily mean that it is not crosslinked. The THF-insoluble content is defined as a value measured as follows.

That is, in the case of the toner of the present invention, the pigment content is measured in advance by a known method. Next, a certain amount of 0.5 to 1.0 g of toner is weighed (W ₁ g), put into a cylindrical filter paper (No. 86R, manufactured by Toyo Roshi), subjected to a Soxhlet extractor, and 20 to 100 ml of THF as a solvent. After extracting for a time and evaporating the soluble component extracted with the solvent, it is vacuum dried at 50 ° C. for several hours, and the amount of the THF-soluble resin component is weighed (W ₂ g). Then, among the pigments contained in the fixed amount of toner, assuming that the mass of the component soluble in THF is W ₃ g and the mass of the component insoluble in THF is W ₄ g, the resin composition according to the following formula: The THF-insoluble matter in it is calculated.

  As the binder resin for the toner used in the present invention, a styrene-acrylic resin is preferable in consideration of matching with the fixing device used in the present invention. When the binder resin is styrene-acrylic, it is difficult for toner to adhere to the fixing roller of the present invention, and therefore it is possible to prevent toner from adhering to the surface heating unit. However, if necessary, the following resins can be used as resins other than styrene-acrylic resins or used in combination. Examples of such resins other than styrene-acrylic resins include polyester resins, epoxy resins, and styrene-butadiene copolymers.

In a method for directly obtaining toner particles by a polymerization method, a monomer for forming a styrene-acrylic resin as a binder resin is used. Specifically, styrene; styrene monomers such as o- (m-, p-) methylstyrene, m- (p-) ethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, acrylic acid Propyl, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (
(Meth) acrylic acid ester monomers such as dimethylaminoethyl acrylate, diethylaminoethyl (meth) acrylate; ene monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile, acrylamide Preferably used.

  These may be used alone or in general so that the theoretical glass transition temperature (Tg) described in the publication “Polymer Handbook 2nd Edition III-P139-192 (John Wiley & Sons)” is 40-75 ° C. Monomers are appropriately mixed and used. When the theoretical glass transition temperature is less than 40 ° C., problems are likely to occur from the viewpoint of storage stability and durability stability of the toner, while when it exceeds 75 ° C., the fixing point of the toner is increased.

  Furthermore, in the present invention, it is preferable to use a crosslinking agent during the synthesis of the binder resin in order to increase the mechanical strength of the toner particles.

  In the present invention, the binder resin is preferably crosslinked to such an extent that the toner has a THF-insoluble content in the above-described range. Among the crosslinking agents used in the present invention, examples of the bifunctional crosslinking agent include divinylbenzene, bis (4-acryloxypolyethoxyphenyl) propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, and 1,4. -Butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 200 , # 400, # 600 diacrylate, dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester type diacrylate (MANDA Japan Drugs), and include those instead dimethacrylate above diacrylate.

  Polyfunctional crosslinkers include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate and its methacrylate, 2,2-bis (4-methacryloxy, polyethoxy Phenyl) propane, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate and triallyl trimellitate.

  These crosslinking agents are preferably used in an amount of 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, with respect to 100 parts by mass of the monomer.

  In the present invention, a resin having polarity such as polyester resin or polycarbonate resin (hereinafter referred to as “polar resin”) can be used in combination. By using such a polar resin in combination with the binder resin, it becomes easy to improve the wax dispersion state in the toner. For example, when a toner is directly produced by a suspension polymerization method described later, a polymerizable monomer composition that forms toner particles and an aqueous system can be obtained by adding the polar resin as described above during the polymerization reaction from the dispersion step to the polymerization step. Depending on the balance of the polarity exhibited by the dispersion medium, the added polar resin can be controlled to form a thin layer on the surface of the toner particles or to have a gradient from the toner particle surface toward the center. At this time, the wax is appropriately present on the toner surface, so that the balance between the fixing property and the charging property can be achieved. In particular, when a polar resin having an acid value of 1 to 20 mg KOH / g is used, it becomes easy to control the dispersion state of the wax.

As addition amount of the said polar resin, it is preferable to use 1-25 mass parts with respect to 100 mass parts of binder resin, More preferably, it is 2-15 mass parts. If the amount is less than 1 part by mass, the presence state of the polar resin in the toner particles becomes non-uniform or the amount of wax exposed on the toner surface increases, which is adversely affected by the wax in terms of toner durability reduction and charging characteristics. Conversely, when the amount exceeds 25 parts by mass, the thin layer of polar resin formed on the surface of the toner particles becomes thick, so that the wax tends to be unevenly distributed inside the toner. In either case, it is difficult to suppress the dispersion state of the wax, which causes a problem with matching with the fixing device and OHP transmittance.

  A typical example of such a polar resin is a polyester resin. The composition of the polyester resin suitably used in the present invention is as follows.

  Examples of the alcohol component of the polyester resin include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6 -Hexanediol, neopentyl glycol, 2-ethyl 1,3-hexanediol, hydrogenated bisphenol A, bisphenol derivatives represented by the following formula (a), and diols represented by the following formula (a):

［式中、Ｒはエチレン又はプロピレン基を示し、ｘ及びｙはそれぞれ１以上の整数であり、かつｘ＋ｙの平均値は２〜１０である。］

[Wherein, R represents an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 10. ]

  In addition, when a reactive polyester resin or polycarbonate resin is used as the polar resin, the charging characteristics of the toner are improved, fog and scattering are improved, and a high-quality image with excellent dot reproducibility can be obtained. . In addition, it becomes possible to impart an appropriate mechanical strength to the toner particles, minimizing the influence of toner deterioration received from the image forming apparatus, and improving the durability against a large number of printouts. Furthermore, it is possible to minimize the influence from the toner manufacturing process such as the toner spheroidizing process for achieving the toner shape distribution as described above and the drying process when the toner is directly manufactured by the polymerization method. . In addition, two or more types of polar resins can be used in combination, and the charging property of the polar resin can be used.

The reactive polyester resin according to the present invention includes terephthalic acid, isophthalic acid, phthalic acid, adipic acid, maleic acid, succinic acid, sebacic acid, thiodiglycolic acid, diglycolic acid, malonic acid, glutaric acid, pimelic acid, Polybasic acids such as suberic acid, azelaic acid, camphoric acid, cyclohexanedicarboxylic acid, trimellitic acid; ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1, 4-butanediol, neopentyl glycol, 1,4-bis (hydroxymethyl) cyclohexane, 1,4-bis (2-hydroxyethyl) benzene, 1,4-cyclohexanedimethanol, polyethylene glycol, polypropylene glycol, bisphenol A A hydrogenated bisphenol, an ethylene oxide adduct of bisphenol A, a propylene oxide adduct of bisphenol A, a polyhydric alcohol such as glycerin, trimethylolpropane, pentaerythritol, and the resulting condensation polymer These have a reactive group in the main chain or side chain. Examples of reactive groups include carboxylic acid (or salt thereof), sulfonic acid (or salt thereof), ethyleneimino acid, epoxy group, isocyanate group, double bond, acid anhydride, and halogen atom. Resin reacts with each other or with a polyfunctional crosslinking agent (eg, polyhydric alcohol, polybasic acid, etc.), and further reacts with reactive polyester and vinyl monomer (eg, esterification, copolymerization, etc.) ) To obtain a THF-insoluble matter. For example, when a toner is obtained by a polymerization method, an unsaturated polyester resin is used as a reactive polyester resin, and this is copolymerized with a vinyl monomer (including a cross-linking agent such as divinylbenzene if necessary). In this case, the unsaturated polyester resin having polarity moves to the vicinity of the toner surface with the progress of polymerization, and forms a thin layer on the surface of the toner particles. Therefore, a toner having particularly excellent blocking resistance and offset resistance is used. It is possible to obtain.

  As the reactive polyester resin that can be used in the present invention, any reactive polyester resin can be used as long as it contains a reactive group as described above. However, if the molecular weight is too low, a polyester resin that does not participate in the crosslinking reaction is formed on the toner surface. It may exist, and blocking resistance may fall. On the other hand, if the molecular weight is too high, for example, when a toner is obtained by a polymerization method, it becomes difficult to dissolve the reactive polyester resin in the vinyl-based monomer, so that the production becomes difficult. Accordingly, the reactive polyester resin having a weight average molecular weight in the range of 3,000 to 100,000 is particularly suitable for obtaining a toner having excellent performance.

  On the other hand, when a polycarbonate resin is used as the polar resin, a polycarbonate resin having a repeating unit represented by the following general formula (I) in the molecular structure is preferably used.

［式中、Ｒは有機基を示す。］

[Wherein, R represents an organic group. ]

  The polycarbonate resin represented by the above general formula (I) has various structures. For example, any known polycarbonate produced by reacting a dihydric phenol and a carbonate precursor by a solution method or a melting method is used. can do. For example, a polymer having a repeating unit having a structure represented by the following general formula (II) may be mentioned.

［式中、Ｒ^２は、水素原子、脂肪族炭化水素基、芳香族置換基であり、このＲ^２が複数の場合、それらは同一であってもよいし、異なっていてもよい。ｍは０〜４の整数であり、Ｚは単結合、脂肪族炭化水素基、芳香族置換基、−Ｓ−、−ＳＯ−、ＳＯ_２−、−Ｏ−、−ＣＯ−結合で表わされる結合を示す。］

[Wherein, R ² represents a hydrogen atom, an aliphatic hydrocarbon group, or an aromatic substituent, and when there are a plurality of R ² , they may be the same or different. m is an integer of 0 to 4, Z is a single bond, an aliphatic hydrocarbon group, an aromatic _{substituent, -S -, - SO-, SO} 2 -, - O -, - CO- bond represented by bond Indicates. ]

  The molecular weight of the polycarbonate resin used in the present invention is not particularly limited, but preferably has a peak molecular weight measured by GPC (gel permeation chromatography) in the range of 1,000 to 500,000, more preferably 2,000 to 100,000. When the peak molecular weight is lower than 1,000, the charging characteristics may be adversely affected. When the peak molecular weight is higher than 500,000, the melt viscosity becomes too high, which may cause a problem in fixability. In producing the polycarbonate resin used in the present invention, an appropriate molecular weight regulator, a branching agent for improving viscoelasticity, a catalyst for promoting the reaction, and the like can be used as necessary.

  The polar resins as described above are not limited to one type of polymer. For example, two or more types of reactive polyester resins can be used simultaneously, or two or more types of vinyl polymers can be used. In addition, completely different types of polymers, such as non-reactive polyester resins, epoxy resins, polycarbonate resins, polyolefins, polyvinyl acetate, polyvinyl chloride, polyalkyl vinyl ethers, polyalkyl vinyl ketones, polystyrenes, poly (meth) acrylic esters Polymers such as melamine formaldehyde resin, polyethylene terephthalate, nylon and polyurethane can be added to the binder resin as necessary.

  In the present invention, a known charge control agent is contained in the toner particles or added to and mixed with the toner particles, whereby the charging speed of the toner can be increased and a constant charge amount can be stably added to the toner. It is possible to maintain. When the toner particles are produced using a direct polymerization method, a charge control agent having no polymerization inhibition and no solubilized product in an aqueous dispersion medium is preferable. Specific compounds include metal compounds of aromatic carboxylic acids such as salicylic acid, naphthoic acid and dicarboxylic acid as negative charge control agents; polymer compounds having a sulfonic acid or carboxylic acid group in the side chain; boron compounds; urea Compound; silicon compound; calixarene. Examples of the positive charge control agent include a quaternary ammonium salt; a polymer compound having the quaternary ammonium salt in the side chain; a guanidine compound; and an imidazole compound.

  It is also preferable to add a polymer having a sulfur atom as another charge control agent. Of the polymers having a sulfur atom, it is more preferable to use a polymer having a sulfonic acid group. By adding a polymer having a sulfonic acid group to the toner, the dispersion state of the wax in the binder is improved, the fixing property on the low temperature side is remarkably improved, and deterioration of the charging property due to the wax can be prevented. . Furthermore, since the polarity of the sulfonic acid group also improves the chargeability of the toner, scattering that occurs during fixing can be sufficiently suppressed, and the image density and fog can be improved.

  Examples of the polymer having a sulfonic acid group used in the present invention include a polymer type compound having a sulfonic acid group in the side chain, and in particular, a methacrylic acid monomer containing a sulfonic acid group has a copolymerization ratio of 2 mass. % Or more, preferably 5% by mass or more, and using a polymer compound comprising a styrene and / or styrene (meth) acrylate copolymer having a glass transition temperature (Tg) of 40 to 90 ° C., The preferred charging characteristics can be enjoyed without affecting the thermal characteristics required of the toner particles.

  As said sulfonic-acid-group-containing (meth) acrylamide type monomer, what can be represented by the following general formula (1) is preferable, and 2-acrylamide-2-methylpropanoic acid and 2-methacrylamide-2-methyl are specifically mentioned. And propanoic acid.

［上記一般式（１）中、Ｒ_１は水素原子、又はメチル基を示し、Ｒ_１とＲ_３は、それぞれ水素原子、Ｃ_１〜Ｃ_１０のアルキル基、アルケニル基、アリール基、又はアルコキシ基を示し、ｎは１〜１０の整数を示す。］

[In the general formula (1), R ₁ represents a hydrogen atom or a methyl group, and R ₁ and R ₃ represent a hydrogen atom, a C _{1 to} C ₁₀ alkyl group, an alkenyl group, an aryl group, or an alkoxy group, respectively. N represents an integer of 1-10. ]

  However, the addition of a charge control agent is not essential in the present invention. For example, when the two-component development method is used, friction charging with the carrier is used, and when the non-magnetic one-component blade coating development method is used, friction charging with the blade member or sleeve member is positively performed. Therefore, it is not always necessary to include a charge control agent in the toner particles.

  The toner used in the present invention further contains a colorant. Among the colorants used in the present invention, as the black colorant, carbon black and those adjusted to black using the following yellow / magenta / cyan colorants are used.

  As the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 155, 168, 174, 176, 180, 181 and 191 are preferably used.

  As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 31, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, 254, 269 are particularly preferred.

  As the cyan colorant, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15, 15: 2, 15: 3, 15: 4, 60, 62, 66 and the like can be used particularly preferably.

  These colorants can be used alone or mixed and further used in the form of a solid solution. The colorant of the present invention is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, transparency on an OHP film, and dispersibility in toner particles. The added amount of the colorant is generally 1 to 20 parts by mass per 100 parts by mass of the binder resin.

  The toner (toner particles) of the present invention can be preferably produced by a suspension polymerization method. In the case of producing a toner by the suspension polymerization method, known inorganic and organic dispersants can be used as a dispersant used in preparing an aqueous dispersion medium. Specifically, as the inorganic dispersant, for example, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, magnesium carbonate, calcium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, Examples include calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina. Examples of organic dispersants that can be used include polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, carboxymethylcellulose sodium salt, and starch.

  Commercially available nonionic, anionic and cationic surfactants can also be used. For example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate can be used.

  In the production of the toner in the present invention, it is preferable to use an inorganic poorly water-soluble dispersant, and it is preferable to use a poorly water-soluble inorganic dispersant that is soluble in an acid. In the present invention, when preparing a water-based dispersion medium using a hardly water-soluble inorganic dispersant, these dispersants are 0.2 to 2.0 with respect to 100 parts by mass of the polymerizable vinyl monomer. It is preferable to use it in such a ratio that it becomes part by mass. Moreover, in this invention, it is preferable to prepare an aqueous dispersion medium using 100-3,000 mass parts water with respect to 100 mass parts of polymerizable monomer compositions.

  In the present invention, when preparing an aqueous dispersion medium in which the above-mentioned poorly water-soluble inorganic dispersant is dispersed, a commercially available dispersant may be used as it is, but a dispersion having a fine uniform particle size may be used. In order to obtain agent particles, a slightly water-soluble inorganic dispersant as described above may be prepared in a liquid medium such as water under high-speed stirring. For example, when tricalcium phosphate is used as a dispersant, a preferred dispersant can be obtained by mixing aqueous sodium phosphate solution and aqueous calcium chloride solution at high speed to form fine particles of tricalcium phosphate. .

  In the aqueous dispersion medium, in addition to the polymerizable monomer constituting the binder resin, a wax, a colorant, a charge control agent, and other toner particle components are mixed and uniformly mixed using a known dispersion method. Disperse.

Specific examples of the polymerization initiator used for polymerization of the polymerizable monomer in toner production include 2,2′-azobis (2,4-dimethylvaleronitrile) and 2,2′-azobisiso. Azo or diazo such as butyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile A polymerization initiator such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide; Although the usage-amount of these polymerization initiators changes with the target degree of polymerization, generally 5-20 mass parts is used with respect to 100 mass parts of polymerizable vinylic monomers. The kind of the polymerization initiator varies slightly depending on the polymerization method, but is used alone or in combination with reference to the 10-hour half-life temperature.

  In order to control the degree of polymerization, a known crosslinking agent, chain transfer agent, polymerization inhibitor and the like may be further added to the polymerizable monomer composition. These additives can be added in advance to the polymerizable monomer composition, and can be appropriately added during the polymerization reaction, if necessary.

  According to the toner manufacturing method as described above, the decrease in the triboelectric charge amount under the high humidity and the decrease in the triboelectric charge rate under the low humidity, which are conventionally seen in the toner containing the charge control agent, are suppressed. In addition, it is possible to easily obtain a toner in which the contamination on the toner carrier or the like is suppressed.

In the present invention, adding an inorganic fine powder as an external additive to toner particles is a preferred embodiment for improving developability, transferability, charging stability, fluidity and durability. As the inorganic fine powder, known ones can be used, but it is preferably selected from silica, alumina, titania or a double oxide thereof. Among these, silica is more preferable. As the silica, both a so-called dry process produced by vapor phase oxidation of silicon halide or alkoxide or dry silica called fumed silica, and so-called wet silica produced from alkoxide, water glass, etc. can be used. Further, dry silica having fewer silanol groups on the surface and inside the silica fine powder and less production residue such as Na ₂ O and SO ₃ ²⁻ is preferable. In dry silica, it is also possible to obtain composite fine powders of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride and titanium chloride together with silicon halogen compounds in the production process. Is also included.

Inorganic fine powder used in the present invention, BET method specific surface area by measuring nitrogen adsorption in the ^{30 m} 2 / g or more, particularly 50 to 400 m ² / g give good results in the range of, to 100 mass parts of the toner 0.3-8 mass parts is used with respect to it, Preferably 0.5-5 mass parts is used.

  By adding the inorganic fine powder having a controlled BET specific surface area as described above to the toner, it is possible to appropriately cover the wax exposed on the toner surface, and to suppress the adverse effect of the wax on the charging characteristics.

  Furthermore, since moderate fluidity is imparted to the toner, the uniform chargeability of the toner is synergistically improved, and excellent effects are maintained even when a large number of printouts are repeated continuously.

When the BET specific surface area of the inorganic fine powder is less than 30 m ² / g, it is difficult to impart appropriate fluidity to the toner. When the BET specific surface area exceeds 400 m ² / g, the fluidity of the toner may be reduced because the inorganic fine powder is embedded in the toner particle surface during continuous printout.

  For the measurement of the specific surface area, nitrogen gas is adsorbed on the sample surface using a specific surface area measuring device “Autosorb 1” (manufactured by Yuasa Ionics), and the specific surface area is calculated by the BET multipoint method.

  Further, when the addition amount of the inorganic fine powder is less than 0.3 part by mass with respect to 100 parts by mass of the toner particles, the effect of addition is hardly exhibited, and when it exceeds 8 parts by mass, the chargeability and fixability of the toner are reduced. Not only does this cause problems, but the matching with the image forming apparatus may be significantly deteriorated by the free inorganic fine powder.

In addition, the inorganic fine powder used in the present invention has a silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, a silane coupling agent, and a functional group as necessary for the purpose of hydrophobization and chargeability control. It is also preferable to have been treated with a treating agent such as a silane coupling agent, other organic silicon compounds, or organic titanium compounds. At this time, the inorganic fine powder may be processed by using two or more kinds of processing agents in combination.

  Furthermore, in order to maintain a high charge amount and achieve a low consumption and a high transfer rate, the inorganic fine powder is preferably treated with at least silicone oil.

  In the toner of the present invention, other additives such as a lubricant powder such as polyethylene fluoride powder, zinc stearate powder, polyvinylidene fluoride powder, cerium oxide powder, silicon carbide powder and the like within a range that does not substantially adversely affect the toner. A polishing agent such as strontium titanate powder; a fluidity imparting agent such as titanium oxide powder or aluminum oxide powder; an anti-caking agent; or a conductivity imparting agent such as carbon black powder, zinc oxide powder or tin oxide powder; A small amount of organic fine particles and inorganic fine particles having opposite polarities can also be used as a developability improver.

  The toner of the present invention can be used as it is as a one-component developer or as a two-component developer by mixing with a carrier.

  When used as a two-component developer, for example, the magnetic carrier mixed with the toner is composed of an element selected from iron, copper, zinc, nickel, cobalt, manganese, and chromium alone or in a ferrite state containing a plurality of elements. The As the shape of the magnetic carrier, any of a spherical shape, a flat shape, and an indefinite shape can be used, and a magnetic carrier whose surface state fine structure (for example, surface unevenness) is appropriately controlled can be used. Also, a resin-coated carrier whose surface is coated with a resin or a magnetic powder-dispersed resin carrier can be suitably used. The average particle diameter of the carrier to be used is preferably 10 to 100 μm, more preferably 20 to 50 μm. Further, when the two-component developer is prepared by mixing these carrier and toner, the toner concentration in the developer is preferably about 2 to 15% by mass.

  Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited thereto.

<Example 1>
First, the image forming apparatus used in this embodiment will be described with reference to FIG.
The image forming apparatus shown in FIG. 2 includes first, second, third and fourth image forming units 26a, 26b, 26c and 26d arranged in parallel, and each image forming unit has its own electrostatic latent image. An image holding member, so-called photosensitive drums 19a, 19b, 19c and 19d are provided.

  Each of the photosensitive drums 19a to 19d has charging portions 16a, 16b, 16c, and 16d; latent image forming means 23a, 23b, 23c, and 23d; developing portions 17a, 17b, 17c, and 17d; 24a, 24b, 24c and 24d; and cleaning portions 18a, 18b, 18c and 18d are arranged in this order.

  In the image forming apparatus having such a configuration, the surface of the photosensitive drum 19a as the image carrier of the first image forming unit 26a is firstly uniformly charged by the charging roller 16a, and the original is read by the latent image forming unit 23a (charging process). In the image, for example, a yellow component color latent image is formed by exposure (exposure step). The latent image is developed with a developer containing yellow toner contained in the developing unit 17a to form a visible yellow image (development process). This yellow toner image is transferred as a transfer material by the transfer unit 24a. Transferred onto the recording material P (transfer process).

While the yellow image is transferred to the recording material P as described above, the second image forming unit 26b forms a magenta component color latent image on the photosensitive drum 19b, and subsequently has the magenta toner of the developing unit 17b. A visible image is formed with the developer. The visible image (magenta toner image) is transferred to a predetermined position of the recording material P when the recording material P, which has been transferred by the first image forming unit 26a, is transferred to the transfer unit 24b. The

  Thereafter, cyan and black component images are formed by the third and fourth image forming units 26c and 26d in the same manner as described above, and a cyan toner image and a black toner image are formed on the same recording material P. Are transferred in layers. After such an image forming process is completed, the recording material P is conveyed to the fixing unit 22 and the image on the recording material P is fixed (fixing step). As a result, a multicolor image is obtained on the recording material P. In this embodiment, fixing is performed using the fixing device shown in FIG. The description regarding the fixing device is as described above.

  The photosensitive drums 19a, 19b, 19c, and 19d that have completed the transfer are subjected to removal of residual toner by the cleaning units 18a, 18b, 18c, and 18d, respectively, and are subjected to subsequent latent image formation.

  In the image forming apparatus, the conveyance belt 25 is used to convey the recording material P as a transfer material. In FIG. 2, the recording material P is conveyed from the right side to the left side. The image forming portions 26a, 26b, 26c and 26d pass through the transfer portions 24a, 24b, 24c and 24d, and are transferred.

  When the recording material P passes through the fourth image forming unit 26d, an AC voltage is applied to the static eliminator 20, the recording material P is neutralized and separated from the belt 25, and then enters the fixing device 22 where the image is fixed and discharged. It is discharged from the outlet 21.

Next, the fixing device will be described.
Specifically, the following fixing devices were used in the examples and comparative examples.
(A) Fixing roller An elastic roller having an outer diameter of 20 mm made of PFA resin having a thickness of 50 μm and a 3 mm-thick silicone rubber layer covering the outer periphery of the core metal was further used.

(B) Pressure roller An elastic roller having an outer diameter of 20 mm, made of a PFA resin having a thickness of 3 μm and covering the outer periphery of a core rubber and further covering the outer periphery of the 3 mm-thick silicone rubber layer, was used.

(C) Fixing nip N1 was formed at a pressure of 100N.

(D) Heat source As the heat source 2b, a resistor was formed by printing on alumina having a width of 8 mm and a thickness of 1 mm, and an output of 700 W was used.

(E) Heated film The surface of a polyimide resin with a thickness of 40 μm was coated with a 10 μm PFA resin, and the circumference was 56.5 mm.

(F) Temperature detector A thermistor was used.

Next, the toner will be described.
In the examples and comparative examples, the ester wax and the hydrocarbon wax used for the toner are the waxes shown in Table 1 and Table 2, respectively.

  First, a polymerized toner was prepared according to the following procedure. 3 parts by weight of tricalcium phosphate is added to 900 g of ion-exchanged water heated to 60 ° C., and stirred at 10,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo) to produce an aqueous medium. did.

  Further, the following formulation was put into a TK type homomixer (made by Tokushu Kika Kogyo Co., Ltd.), heated to 60 ° C., then used, stirred at 9,000 rpm, dissolved and dispersed to obtain an aqueous dispersion medium. .

* Styrene 80 mass parts * n-butyl acrylate 20 mass parts * C.I. I. Pigment Blue 15: 3 5 parts by mass / aluminum salicylate compound 0.03 parts by mass (Bontron E-88: manufactured by Orient Chemical Co., Ltd.)
-0.5 mass part of polymer having a sulfur atom (Acrybase FCA-1001-NS: manufactured by Fujikura Kasei Co., Ltd.)
Polyester resin 5 parts by mass (polycondensation product of propylene oxide modified bisphenol A and isophthalic acid, Tg = 65 ° C., Mw = 10000, Mn = 6000)
-Ester wax (1) 5 parts by mass-Hydrocarbon wax (1) 2 parts by mass-Divinylbenzene 0.05 part by mass

  In this, 3 parts by mass of a polymerization initiator 2,2'-azobis (2,4-dimethylvaleronitrile) was dissolved to prepare a polymerizable monomer composition.

  The polymerizable monomer composition was put into the aqueous medium, and granulated by stirring at 8,000 rpm using a TK homomixer at 60 ° C. in a nitrogen atmosphere. Then, the temperature was raised to 70 ° C. over 2 hours while stirring by transferring to a propeller type stirring device, and further 4 hours later, the temperature was raised to 80 ° C. at a rate of temperature rise of 40 ° C./Hr and reacted at 80 ° C. for 5 hours. To produce polymer particles. After the completion of the polymerization reaction, the slurry containing the particles was cooled, washed with an amount of water 10 times that of the slurry, filtered and dried, and then the particle diameter was adjusted by classification to obtain cyan toner particles.

  To 100 parts by mass of the cyan toner particles, 1.5 parts of silica (R972 manufactured by Aerosil Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Miike Co., Ltd.) to obtain the cyan toner in the present invention. The obtained cyan toner is defined as toner (A).

  The obtained toner (A) was subjected to DSC measurement to determine the endothermic peak characteristics of P1 and P2 and the endothermic peak intensity ratio (P1 / P2) of P1 and P2. Table 3 shows the results obtained by the DSC measurement, the measurement results of the THF-insoluble matter, and the toner formulation. The DSC measurement conditions were as described above.

  The toner (A) was put in the developing machine 17c in FIG. 1, and 10,000 printout images were performed in the single color mode under the following conditions. The process speed is higher than the conventional value of about 100 mm / s, and the process speed is 200 mm / s, which is a more severe condition for the fixing property. Further, A4 size 75 g paper was used as the paper type, a solid image with an image ratio of 5% was output, and adjustment was always performed so that the solid image density was always in the range of 1.40 ± 0.15.

In addition, image density uses "Mugbeth reflection densitometer RD-6DS" (made by Magbes),
A relative density value for a printout image of a white background portion having an original density of 0.00 was used.

  Evaluation was performed by the following method. In addition, Examples 2-11 and Comparative Examples 1-4 were performed according to the same evaluation method.

[OHP transmittance]
The OHP transmittance is measured by outputting a solid image with a toner loading on the OHP film of 0.6 mg / cm ² and using an Shimadzu UV spectrophotometer UV2200 (manufactured by Shimadzu Corporation). The single transmittance was set to 100%, and the transmittance at the maximum absorption wavelength at 500 nm was measured. As the transmittance is closer to 100%, a better OHP projection image is obtained. If the transmittance value is 50% or more, it is a usable level. However, if this value is less than 50%, the color image is dark and cannot be used.

[Matching with surface heating unit]
After the initial evaluation of the printout images of 5,000 sheets and 10,000 sheets, the adhesion state and scratches of the toner on the surface heating unit were visually observed and evaluated according to the following evaluation criteria.

A: Not generated B: Slightly fixed C: Fixed or scratched D: Many fixed and scratched

[Matching with fixing roller]
After the initial evaluation of the printout images of 5,000 sheets and 10,000 sheets, the adhesion state and scratches of the toner on the fixing roller were visually observed and evaluated according to the following evaluation criteria.

A: Not generated B: Slightly fixed C: Fixed or scratched D: Many fixed and scratched

[Low-temperature fixability]
The temperature of the fixing roller surface decreased due to the output of 10,000 printout images, and the number of offset images generated was measured and evaluated according to the following evaluation criteria.

A: Not generated B: Less than 10 sheets C: 10 sheets or more and less than 100 sheets D: 100 sheets or more

  The evaluation results are shown in Table 4. As a result of evaluating the toner (A) by the above evaluation method, good results were obtained in each item.

<Example 2>
In Example 1, it manufactured like Example 1 except having changed the addition amount of divinylbenzene into 5 mass parts. The obtained toner is defined as a toner (B). This toner was evaluated in the same manner as in Example 1. As a result, although the OHP transmittance was slightly inferior, almost good results were obtained.

<Example 3>
In Example 1, it manufactured like Example 1 except having changed the addition amount of the initiator into 15 mass parts, and not adding the addition amount of divinylbenzene. The obtained toner is defined as a toner (C). The toner was evaluated in the same manner as in Example 1. As a result, although the matching between the surface heating unit and the fixing roller was slightly inferior, generally good results were obtained.

<Example 4>
Polyester resin 100 parts by mass (polycondensation product of propylene oxide modified bisphenol A and isophthalic acid, Tg = 65 ° C., Mw = 10000, Mn = 6000)
・ C. I. Pigment Blue 15: 3 5 parts by mass / Aluminum salicylate compound 0.03 parts by mass (Bontron E-88: manufactured by Orient Chemical Co., Ltd.)
-0.5 part by mass of a polymer having a sulfur atom (Acrybase FCA-1001-NS: manufactured by Fujikura Kasei Co., Ltd.)
-Ester wax (1) 5 parts by mass-Hydrocarbon wax (1) 2 parts by mass

The mixture having the above formulation was heat-kneaded by a conventional method, cooled and pulverized, spheronized, and classified to obtain cyan toner particles having an Mw of 7.0 μm. Next, 100 parts by mass of the cyan toner particles, hydrophobized titanium oxide with an average major axis of 30 nm, and hydrophobized silica fine particles (specific surface area 120 m ² / g) were added by 1.0 part by mass in a dry manner. The toner particles were given fluidity. The obtained toner is defined as a toner (D). The toner was evaluated in the same manner as in Example 1. As a result, although the matching with the OHP transmittance, the surface heating unit, and the fixing roller was slightly inferior, generally good results were obtained.

<Example 5>
In Example 2, the amount of ester wax (1) added was 12 parts by mass, and 2 parts by mass of hydrocarbon wax (2) was added instead of hydrocarbon wax (1). Manufactured. The obtained toner is defined as a toner (E). This toner was evaluated in the same manner as in Example 1. As a result, although the OHP transmittance was inferior, a generally good result was obtained.

<Example 6>
In Example 2, it manufactured like Example 2 except adding 2 mass parts of hydrocarbon wax (3) instead of hydrocarbon wax (1). The obtained toner is defined as a toner (F). The toner was evaluated in the same manner as in Example 1. As a result, although the matching with the OHP transmittance, the surface heating unit, and the fixing roller was slightly inferior, generally good results were obtained.

<Example 7>
In Example 2, a toner was produced in the same manner as in Example 2 except that 2 parts by mass of the hydrocarbon wax (4) was added instead of the hydrocarbon wax (1). The obtained toner is defined as a toner (G). As a result of evaluating this toner in the same manner as in Example 1, the OHP transmittance was inferior, but it was at a level with no problem.

<Example 8>
In Example 7, instead of the ester wax (1), 5 parts by mass of the ester wax (2) was added, and the addition amount of the hydrocarbon wax (4) was changed to 0.2 parts by mass. In the same manner as in Example 7, a toner was produced. The obtained toner is defined as a toner (H). This toner was evaluated in the same manner as in Example 1. As a result, the OHP transmittance was inferior and the fixing property on the low temperature side was slightly inferior, but it was at a level with no problem.

<Example 9>
In Example 7, a toner was produced in the same manner as in Example 8, except that 5 parts by mass of ester wax (3) was added instead of ester wax (2). The obtained toner was designated as toner (I). As a result of evaluating this toner in the same manner as in Example 1, the OHP transmittance was inferior.

<Example 10>
In Example 1, a toner was manufactured in the same manner as in Example 1 except that the amount of ester wax (1) added was changed to 50 parts by mass. The obtained toner is defined as a toner (J). As a result of evaluating this toner in the same manner as in Example 1, the matching with the surface heating unit was inferior.

<Example 11>
In Example 1, it manufactured like Example 1 except having changed the addition amount of ester wax (1) into 0.03 mass part. The obtained toner is defined as toner (K). This toner was evaluated in the same manner as in Example 1. As a result, the fixing property on the low temperature side was inferior.

<Comparative example 1>
In Example 1, it manufactured like Example 1 except adding 5 mass parts of ester wax (4) instead of ester wax (1). The obtained toner is defined as a toner (a). This toner was evaluated in the same manner as in Example 1. As a result, after 10,000 sheets were printed out, the toner on the surface heating unit was markedly adhered and scratched.

<Comparative example 2>
In Example 1, it manufactured like Example 1 except adding 2 mass parts of hydrocarbon waxes (5) instead of a hydrocarbon wax (1). The obtained toner is defined as a toner (b). This toner was evaluated in the same manner as in Example 1. As a result, the fixing property on the low temperature side was significantly reduced.

<Comparative Example 3>
In Example 1, it manufactured like Example 1 except not adding hydrocarbon wax (1). The obtained toner is defined as a toner (c). As a result of evaluating this toner in the same manner as in Example 1, remarkable toner adhesion and scratches on the surface heating unit and the fixing roller were observed.

<Comparative example 4>
In Example 1, it manufactured like Example 1 except not adding ester wax (1). The obtained toner is defined as a toner (d). As a result of evaluating this toner in the same manner as in Example 1, the OHP transmittance and the fixing property on the low temperature side were markedly deteriorated.

  Table 3 shows the prescriptions and physical properties of the toners (A) to (K) and (a) to (d), and Table 4 shows the results of printout image evaluation.

  As described above, according to the present invention, as a fixing device, a toner image on a transfer material, a rotating member, a counter member that forms a nip with the rotating member, and a rotating member that is different from the nip are rotated. A heating member that heats at a body surface part, and a temperature control method that controls a heating temperature of the rotating body by the heating member, and a material to be heated is inserted into the nip, nipped and conveyed, and heated by the heat of the rotating body A toner having a specific peak in the DSC curve at the time of temperature rise measured by a differential scanning calorimeter (DSC) is used as the toner. Thus, it is possible to provide an image forming apparatus with improved OHP transmittance and good matching with the fixing device.

1 is a schematic cross-sectional view showing an example of a fixing device that can suitably carry out the image forming method of the present invention. Schematic cross-sectional view showing an example of an image forming apparatus capable of suitably carrying out the image forming method of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixing roller 2a Heating film 2b Ceramic heater 2c Heater holder 3 Pressure roller 5 Temperature detection means 16a, 16b, 16c, 16d Charge roller 17a, 17b, 17c, 17d Developing device 18a, 18b, 18c, 18d Cleaning device 19a, 19b, 19c, 19d Photosensitive drum 20 Static eliminator 21 Discharge port 22 Fixing device 23a, 23b, 23c, 23d Latent image forming means 24a, 24b, 24c, 24d Transfer section 25 Conveyor belt

Claims (9)

At least (a) a charging step for charging an image carrier for carrying an electrostatic latent image, (b) an exposure step for forming an electrostatic latent image on the charged image carrier by exposure, (c) A developing step of forming a toner image on the image carrier by developing the electrostatic latent image with toner carried on the surface of the toner carrier; (d) a toner image formed on the surface of the image carrier; The image forming method includes: a transfer step of transferring to a transfer material with or without an intermediate transfer member; and (e) a fixing step of heating and fixing the toner image on the transfer material onto the transfer material. And
In the fixing step, a rotating member, a counter member having a rotating shaft parallel to the rotating member and forming a nip by being pressed against the rotating member, and the rotating member are heated at a surface portion other than the nip. A heating member, and a temperature control means for controlling the temperature of the rotating body heated by the heating member, wherein the transfer material is nipped and conveyed through the nip, and the transfer material is heated by the rotating body. A process of fixing using a fixing device,
The toner contains at least a binder resin, a colorant and a wax, and endothermic peaks P1 and 55 existing in a range of 55 to 120 ° C. in a DSC curve at the time of temperature rise measured by a differential scanning calorimeter (DSC). An image forming method characterized by having an endothermic peak P2 that is in a range of 120 ° C. and exists on a higher temperature side than the endothermic peak P1. The wax includes an ester wax and a hydrocarbon wax, the endothermic peak P1 is a peak derived from an ester wax, the endothermic peak P2 is a peak derived from a hydrocarbon wax, and an intensity ratio between the endothermic peak P1 and the endothermic peak P2 ( 2. The image forming method according to claim 1, wherein P1 / P2) is 0.1 to 10. 3. The image forming method according to claim 1, wherein a half width of the endothermic peak P1 is within 10 [deg.] C., and a half width of the endothermic peak P2 is 5 to 25 [deg.] C. 4. The image forming method according to claim 2, wherein the ester wax has a weight average molecular weight (Mw) of 350 to 1500. The image forming method according to any one of claims 2 to 4, wherein the hydrocarbon wax has a weight average molecular weight (Mw) of 300 to 4,000. The image forming method according to claim 2, wherein the hydrocarbon wax has a solubility in styrene at 25 ° C. of 5 to 60% by mass. The image forming method according to claim 1, wherein the binder resin includes a styrene-acrylic resin. The image forming method according to claim 1, wherein an insoluble content of the toner in tetrahydrofuran (THF) is 0.1 to 40% by mass. A toner for visualizing an electrostatic latent image formed on an image carrier,
(A) a charging step of charging an image carrier for carrying an electrostatic latent image, (b) an exposure step of forming an electrostatic latent image on the charged image carrier by exposure, (c) the electrostatic Developing the latent image with the toner carried on the surface of the toner carrying member to form a toner image on the image carrying member; and (d) intermediately forming the toner image formed on the surface of the image carrying member. A transfer step of transferring to a transfer material with or without a transfer body; and (e) a rotating body and a rotating shaft parallel to the rotating body and facing the rotating body to form a nip. A member, a heating member for heating the rotating body at a surface portion other than the nip, and temperature control means for controlling the temperature of the rotating body heated by the heating member, and transferring a transfer material to the nip. The heating constant is inserted and nipped and conveyed, and the transfer material is heated by the rotating body. The device, a fixing step of fixing onto the transfer material by heating the toner image on the transfer material is used in an image forming method having,
It contains at least a binder resin, a colorant and a wax, and has endothermic peaks P1 and 55-120 ° C. in the range of 55-120 ° C. in the DSC curve at the time of temperature rise measured by a differential scanning calorimeter (DSC). A toner having an endothermic peak P2 that is in a range and is on a higher temperature side than the endothermic peak P1.

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