JP2009288516A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device and an image forming apparatus of an electromagnetic inductive heating method which produces no "wax sticking image" on a recording medium outputted by printing even when toner containing paraffin wax of a melting point in the range of 60 to 90°C is used. <P>SOLUTION: A coil guide 28 is formed such that the wettability to paraffin wax on an opposite surface 28a opposing a fixing member is improved as compared to the wettability to paraffin wax on a non-opposite surface 28b which does not oppose the fixing member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a combination machine thereof, and a fixing device installed therein, and more particularly, an electromagnetic for fixing a toner containing paraffin wax on a recording medium. The present invention relates to an induction heating type fixing device and an image forming apparatus.

Conventionally, in an image forming apparatus such as a copying machine or a printer, an electromagnetic induction heating type fixing device is known (for example, see Patent Document 1).
Specifically, the electromagnetic induction heating type fixing device includes a fixing member such as a fixing roller and a fixing belt, a pressure member that presses against the fixing member to form a nip portion, and electromagnetically fixes the fixing member facing the outer peripheral surface of the fixing member. An induction heating unit for induction heating is used. The induction heating unit includes an exciting coil, a core that covers the exciting coil, a coil guide that holds the exciting coil and faces the fixing member, and the like. When the exciting coil of the induction heating unit is energized, a magnetic flux is formed around the heat generating layer of the fixing member (or the heat generating layer of the heating member in contact with the fixing member), and the heat generating layer is electromagnetically heated, The fixing member is heated directly (or indirectly). Thus, the toner on the recording medium that contacts the fixing member at the position of the nip is heated and melted, and the toner is fixed on the recording medium.
Here, in order to improve the heating efficiency of the fixing member, the induction heating unit (coil guide) is disposed so as to face the fixing member with a small gap.

  On the other hand, Patent Document 2, Patent Document 3 and the like improve low-temperature fixability and improve the separation property (release property) of the recording medium with respect to the fixing member and the pressure member without applying oil to the fixing member. For this purpose, a technique for incorporating a paraffin wax having a melting point in the range of 60 to 90 ° C. into a toner used in an image forming process is disclosed.

  On the other hand, Patent Document 4 and the like disclose a technique of cleaning a wax filmed on a fixing belt by reversely rotating a pressure roller that is in pressure contact with the fixing belt, which is a fixing device of a heater type. Yes.

JP 2008-40176 A JP 2008-76565 A JP 2008-97046 A JP 2007-52296 A

  The above-described conventional electromagnetic induction heating type fixing device is intended to improve the low-temperature fixing property and to improve the separation property (release property) of the recording medium with respect to the fixing member and the pressure member without applying oil to the fixing member. When a toner containing paraffin wax having a melting point in the range of 60 to 90 ° C. is used, the induction heating unit (coil) in which the paraffin wax volatilized at the position of the nip or the surface of the fixing member is opposed to the fixing member. There was a problem that the paraffin wax adhered to the opposing surface of the guide) was fixed. When the amount of paraffin wax that adheres to and accumulates on the opposite surface of the induction heating unit (coil guide) increases and the accumulated height exceeds a minute gap with the fixing member, the induction heating unit A part of the paraffin wax adhered to the fixing member adheres to the fixing member. Then, the paraffin wax adhering to the fixing member adheres to the recording medium at the position of the nip portion during the fixing process (the image on the recording medium to which the wax adheres in this way is referred to as “wax adhesion image”). .

  The present invention has been made to solve the above-described problems, and is a recording medium that is printed out even when a toner containing paraffin wax having a melting point in the range of 60 to 90 ° C. is used. An object of the present invention is to provide an electromagnetic induction heating type fixing device and an image forming apparatus in which no “wax adhesion image” is generated.

  According to a first aspect of the present invention, a fixing device includes a fixing member that heats and melts toner to fix it on a recording medium, and an induction heating unit that heats the fixing member directly or indirectly by electromagnetic induction. The toner contains paraffin wax having a melting point in the range of 60 to 90 ° C., and the induction heating unit includes a coil guide that faces the outer peripheral surface of the fixing member and holds an exciting coil. The coil guide is formed so that the wettability with respect to the paraffin wax on the facing surface facing the fixing member is better than the wettability with respect to the paraffin wax on the non-facing surface not facing the fixing member. It is.

  According to a second aspect of the present invention, in the fixing device according to the first aspect of the invention, the coil guide is configured such that the surface roughness of the facing surface is rougher than the surface roughness of the non-facing surface. It is formed.

  According to a third aspect of the present invention, in the fixing device according to the second aspect, the opposed surface of the coil guide has an arithmetic average roughness (Ra) of 3 μm or more or a ten-point average roughness ( Rz) is formed to be 15 μm or more.

  According to a fourth aspect of the present invention, there is provided the fixing device according to any one of the first to third aspects, wherein the coil guide includes a surface portion connected to a lower end of the facing surface, and the surface portion. Is formed so that the wettability with respect to the paraffin wax is equal to the wettability with respect to the paraffin wax of the opposite surface.

  According to a fifth aspect of the present invention, there is provided the fixing device according to any one of the first to fourth aspects, wherein the facing surface of the coil guide has improved wettability to the paraffin wax. The range in the width direction formed in this way is formed so as to include at least the range in the width direction of the maximum recording medium capable of passing paper.

  The fixing device according to a sixth aspect of the present invention is the fixing device according to any one of the first to fifth aspects, wherein the opposed surface of the coil guide is against the paraffin wax by sandblasting or embossing. A range having good wettability is formed.

  An image forming apparatus according to a seventh aspect of the present invention includes the fixing device according to any one of the first to sixth aspects.

  In the present invention, since the coil guide of the induction heating unit is formed so that the wettability to the paraffin wax on the facing surface facing the fixing member is improved, the paraffin wax having a melting point in the range of 60 to 90 ° C. Even when the contained toner is used, it is possible to provide an electromagnetic induction heating type fixing device and an image forming apparatus in which a “wax-attached image” does not occur on a recording medium to be printed out.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

Embodiment 1 FIG.
The first embodiment of the present invention will be described in detail with reference to FIGS.
First, the configuration and operation of the entire image forming apparatus will be described with reference to FIG.
In FIG. 1, 1 is the main body of a tandem type color copier as an image forming apparatus, 2 is a writing unit that emits laser light based on input image information, 4 is a document reading unit that reads image information of a document D, and 7 is A paper supply unit for storing a recording medium P such as transfer paper, 11Y, 11M, 11C, and 11BK are photosensitive drums on which toner images of respective colors (yellow, magenta, cyan, and black) are formed, and 12 is a photosensitive drum. 11Y, 11M, 11C, and 11BK are charged. 13 is a developing unit that develops an electrostatic latent image formed on each photoconductor drum 11Y, 11M, 11C, and 11BK, and 15 is each photoconductor drum 11Y. A cleaning unit that collects untransferred toner on 11M, 11C, and 11BK is shown.
Reference numeral 16 denotes an intermediate transfer belt cleaning unit that cleans the intermediate transfer belt 17, 17 an intermediate transfer belt on which toner images of a plurality of colors are transferred, and 18 a color image formed on the intermediate transfer belt 17 as a recording medium. A secondary transfer roller 19 for transferring the toner image onto P is an electromagnetic induction heating type fixing device for fixing a toner image (unfixed image) on the recording medium P.

Hereinafter, an operation during normal color image formation in the image forming apparatus will be described.
First, image information of the document D placed on the contact glass 5 is optically read by the document reading unit 4. Specifically, the document reading unit 4 scans the image of the document D on the contact glass 5 while irradiating light emitted from an illumination lamp. Then, the light reflected by the document D is imaged on the color sensor via the mirror group and the lens. The color image information of the document D is read for each RGB (red, green, blue) color separation light by the color sensor, and then converted into an electrical image signal. Further, color conversion processing, color correction processing, spatial frequency correction processing, and the like are performed by the image processing unit based on the RGB color separation image signals to obtain yellow, magenta, cyan, and black color image information.
Then, the image information of each color of yellow, magenta, cyan, and black is transmitted to the writing unit 2. The writing unit 2 emits laser light (exposure light) based on the image information of each color toward the corresponding photosensitive drums 11Y, 11M, 11C, and 11BK.

On the other hand, the four photosensitive drums 11Y, 11M, 11C, and 11BK are rotated clockwise in FIG. First, the surfaces of the photoconductor drums 11Y, 11M, 11C, and 11BK are uniformly charged at a portion facing the charging unit 12 (this is a charging process). Thus, a charged potential is formed on the photosensitive drums 11Y, 11M, 11C, and 11BK. Thereafter, the charged surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK reach the irradiation positions of the respective laser beams.
In the writing unit 2, laser light corresponding to the image signal is emitted from the four light sources corresponding to each color. Each laser beam passes through a separate optical path for each of the yellow, magenta, cyan, and black color components (this is an exposure process).

  Laser light corresponding to the yellow component is irradiated on the surface of the first photosensitive drum 11Y from the left side of the drawing. At this time, the yellow component laser light is scanned in the rotational axis direction (main scanning direction) of the photosensitive drum 11Y by a polygon mirror that rotates at high speed. Thus, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 11Y after being charged by the charging unit 12.

  Similarly, the laser beam corresponding to the magenta component is irradiated to the surface of the second photosensitive drum 11M from the left side of the paper, and an electrostatic latent image corresponding to the magenta component is formed. The cyan component laser light is applied to the surface of the third photosensitive drum 11C from the left side of the paper, and an electrostatic latent image of the cyan component is formed. The black component laser beam is applied to the surface of the fourth photosensitive drum 11BK from the left side of the paper, and an electrostatic latent image of the black component is formed.

Thereafter, the surfaces of the photoconductive drums 11Y, 11M, 11C, and 11BK on which the electrostatic latent images of the respective colors are formed reach positions facing the developing unit 13, respectively. Then, the respective color toners are supplied from the developing units 13 onto the photosensitive drums 11Y, 11M, 11C, and 11BK, and the latent images on the photosensitive drums 11Y, 11M, 11C, and 11BK are developed (development process). .)
Thereafter, the surfaces of the photoconductive drums 11Y, 11M, 11C, and 11BK after the development process reach the facing portions of the intermediate transfer belt 17, respectively. Here, a transfer bias roller (not shown) is installed at each facing portion so as to abut on the inner peripheral surface of the intermediate transfer belt 17. Then, the toner images of the respective colors formed on the photoconductive drums 11Y, 11M, 11C, and 11BK are sequentially transferred to the intermediate transfer belt 17 at the position of the transfer bias roller (primary transfer process). .)

Then, the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK after the primary transfer process reach positions facing the cleaning unit 15, respectively. Then, the untransferred toner remaining on the photosensitive drums 11Y, 11M, 11C, and 11BK is collected by the cleaning unit 15 (this is a cleaning process).
Thereafter, the surfaces of the photoconductive drums 11Y, 11M, 11C, and 11BK pass through a neutralization unit (not shown), and a series of image forming processes on the photoconductive drums 11Y, 11M, 11C, and 11BK is completed.

Thereafter, the intermediate transfer belt 17 on which the toner images of the respective colors are transferred in a superimposed manner reaches a position facing the secondary transfer roller 18. At this position, the secondary transfer backup roller sandwiches the intermediate transfer belt 17 between the secondary transfer roller 18 and forms a secondary transfer nip. The four-color toner images formed on the intermediate transfer belt 17 are transferred onto the recording medium P conveyed to the position of the secondary transfer nip (secondary transfer process). At this time, untransferred toner that has not been transferred to the recording medium P remains on the intermediate transfer belt 17.
Thereafter, the intermediate transfer belt 17 reaches the position of the intermediate transfer cleaning unit 16. At this position, the untransferred toner on the intermediate transfer belt 17 is collected.
Thus, a series of transfer processes performed on the intermediate transfer belt 17 is completed.

Here, the recording medium P transported to the position of the secondary transfer nip passes through a transport path K1 in which a paper feed roller 8, a registration roller, and the like are installed from a paper feed unit 7 disposed below the apparatus main body 1. It was transported via.
Specifically, a plurality of recording media P are stored in the paper supply unit 7 in a stacked manner. When the paper feed roller 8 is rotationally driven counterclockwise in FIG. 1, the uppermost recording medium P is fed toward the transport path K1.

  The recording medium P transported to the transport path K1 temporarily stops at the position of the roller nip of the registration roller (not shown) that has stopped rotating. Then, the registration roller is driven to rotate in synchronization with the color image on the intermediate transfer belt 17, and the recording medium P is conveyed toward the secondary transfer nip. In this way, a desired color image is transferred onto the recording medium P.

Thereafter, the recording medium P on which the color image is transferred at the position of the secondary transfer nip is conveyed to the position of the fixing device 19. At this position, the color image transferred to the surface is fixed on the recording medium P by heat and pressure generated by the fixing roller and the pressure roller.
The recording medium P after the fixing process is discharged as an output image by the paper discharge roller 9 to the outside of the apparatus main body 1 (moving in the direction indicated by the broken line arrow), and a series of image forming processes is completed.

Next, the configuration and operation of the fixing device 19 installed in the image forming apparatus main body 1 will be described in detail.
As shown in FIG. 2, the fixing device 19 includes an induction heating unit 25 (magnetic flux generating means), a fixing roller 20 as a fixing member facing the induction heating unit 25, and a pressure as a pressure member that presses against the fixing roller 20. The roller 30, the inlet guide plate 41, the spur guide plate 42, the separation guide plate 43, the outlet guide plate 50, the thermistors 61 and 62, etc.

Here, the fixing roller 20 as a fixing member is formed by sequentially laminating a heat insulating elastic layer 22 made of foamed silicone rubber or the like and a sleeve layer 21 on a cored bar 23 made of iron or stainless steel, The outer diameter is about 40 mm.
The sleeve layer 21 of the fixing roller 20 is a multilayer structure in which a base material layer, a first antioxidant layer, a heat generating layer, a second antioxidant layer, an elastic layer, and a release layer are sequentially laminated from the inner peripheral surface side. Specifically, the base material layer is formed of stainless steel having a layer thickness of about 40 μm, and the first antioxidant layer and the second antioxidant layer are formed by strike plating treatment of nickel having a layer thickness of 1 μm or less. The heating layer is made of copper having a layer thickness of about 10 μm, the elastic layer is made of silicone rubber having a layer thickness of about 150 μm, and the release layer has a layer thickness of about 30 μm. It is formed of PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer).
In the fixing roller 20 configured as described above, the heat generating layer of the sleeve layer 21 is electromagnetically heated by the magnetic flux generated from the induction heating unit 25. The configuration of the fixing roller 20 is not limited to that of the first embodiment. For example, the sleeve layer 21 can be separated without being bonded to the heat insulating elastic layer 22 (fixing auxiliary roller). However, when the sleeve layer 21 (fixing sleeve) is separated, it is preferable to install a member for preventing the sleeve layer 21 from moving in the width direction (thrust direction) during operation.

Here, a spur guide plate 42 in which a plurality of spurs are juxtaposed in the width direction is installed at a position facing the fixing roller 20 and upstream of the nip portion (upstream in the transport direction). The spur guide plate 42 is disposed at a position facing the fixing surface (the surface on which the image is fixed) of the recording medium P fed into the nip portion, and guides the recording medium P to the nip portion. It is. The spur guide plate 42 is formed in a sawtooth shape so that a spur does not rub even if the spur contacts an unfixed image on the recording medium P.
A separation guide plate 43 is provided at a position facing the fixing roller 20 and facing the fixing surface of the recording medium P sent from the nip (on the downstream side in the conveyance direction of the nip). Has been. The separation guide plate 43 is for preventing a problem that the recording medium P after the fixing process sent out from the nip portion is attracted to and wound around the fixing roller 20. That is, when the recording medium P after the fixing process is attracted to the fixing roller 20, the separation guide plate 43 comes into contact with the leading end of the recording medium P to forcibly separate the recording medium P from the fixing roller 20. .

Further, a thermistor 62 as a contact-type temperature detection sensor that contacts the fixing roller 20 is disposed upstream of the nip (on the upstream side in the conveyance direction of the recording medium P) and close to the nip. It is installed. The thermistor 62 is disposed at the end in the width direction on the drive unit side, and detects the surface temperature of the end in the width direction of the fixing roller 20.
Although not shown, a thermopile (non-contact type temperature detection sensor) is disposed at a position facing the center in the width direction of the fixing roller 20.
Then, the temperature on the fixing roller 20 (fixing temperature) is detected by the thermistor 62 and the thermopile, and the heating amount by the induction heating unit 25 is adjusted based on the detection result by the thermistor 62 and the thermopile. In the first embodiment, the induction heating unit 25 is controlled so that the fixing temperature during the fixing process (when passing paper) is 160 to 165 ° C.

Referring to FIG. 2, a pressure roller 30 as a pressure member is formed on a cylindrical member 32 made of aluminum, copper or the like, an elastic layer 31 made of silicone rubber or the like, a release layer made of PFA or the like (not shown). Is formed). The elastic layer 31 of the pressure roller 30 is formed to have a thickness of 1 to 5 mm. The release layer of the pressure roller 30 is formed so that the layer thickness is 20 to 50 μm. The pressure roller 30 is in pressure contact with the fixing roller 20. Then, the recording medium P is conveyed to a pressure contact portion (a nip portion) between the fixing roller 20 and the pressure roller 30.
In the first embodiment, a heater 33 such as a halogen heater is provided in the pressure roller 30 in order to increase the heating efficiency of the fixing roller 20. By supplying electric power to the heater 33, the pressure roller 30 is heated by the radiant heat of the heater 33, and the surface of the fixing roller 20 is heated via the pressure roller 30.

A thermistor 61 as a contact-type temperature detection sensor that contacts the pressure roller 30 is located upstream of the nip portion (on the upstream side in the conveyance direction of the recording medium P) and close to the nip portion. It is arranged. The thermistor 61 is disposed at the end in the width direction on the drive unit side and detects the surface temperature of the end in the width direction of the pressure roller 30.
Although not shown, a thermopile (non-contact type temperature detection sensor) is disposed at a position facing the central portion in the width direction of the pressure roller 30.
Then, the temperature on the pressure roller 30 is detected by the thermistor 61 or the thermopile, and the heating amount by the heater 33 is adjusted based on the detection result by the thermistor 61 or the thermopile.

Here, at a position facing the pressure roller 30 and a position facing the non-fixing surface of the recording medium P fed into the nip portion (on the upstream side of the nip portion), the inlet guide plate 41. Is installed. The inlet guide plate 41 guides the recording medium P fed into the nip portion to the nip portion.
Further, an exit guide plate 50 is installed at a position facing the pressure roller 30 and facing the non-fixing surface of the recording medium P sent from the nip portion (on the downstream side of the nip portion). Has been. The exit guide plate 50 is for guiding the recording medium P after the fixing process sent from the nip portion toward the conveyance path after the fixing process.
With reference to FIG. 3, a grip portion 70 is installed on the outlet guide plate 50. Then, when a jam of the recording medium P occurs at the position of the fixing device 19 (such as a phenomenon in which the recording medium P being transported is jammed), an operator such as a user or a serviceman (the main part of the fixing device 19 ( 3) is taken out from the apparatus main body 1, the gripping portion 70 is gripped, and the outlet guide plate 50 is rotated around the rotation shaft portion 50a (rotation in the direction of the arrow in FIG. 2). Thus, the jammed paper is pulled out from the nip portion with the nip portion exposed. FIG. 4 is a perspective view showing the induction heating unit 25 in a state in which the main part (shown in FIG. 3) of the fixing device 19 is separated.

The induction heating unit 25 includes an excitation coil 26 (coil unit), a core unit 27 (excitation coil core), a coil guide 28, and the like. The exciting coil 26 is wound in the width direction (in the direction perpendicular to the paper in FIG. 2) by winding a litz wire bundled with thin wires on a coil guide 28 disposed so as to cover a part of the outer peripheral surface of the fixing roller 20. It is extended.
The coil guide 28 is made of a resin material having high heat resistance such as PET (polyethylene terephthalate) containing about 45% of a glass material, and faces the outer peripheral surface of the fixing roller 20 and holds the exciting coil 26. In the first embodiment, the gap between the facing surface 28a of the coil guide 28 (induction heating unit 25) and the outer peripheral surface of the fixing roller 20 is set to 2 ± 0.1 mm.
The core portion 27 is made of a ferromagnetic material such as ferrite (having a relative magnetic permeability of about 2500), and is used to form an efficient magnetic flux toward the heat generating layer of the fixing roller 20, and includes an arch core and a center core. It is composed of a side core and the like.
Referring to FIG. 4, induction heating unit 25 is configured to be separable from the main part of fixing device 19. The main part (the unit shown in FIG. 3) of the fixing device 19 is separated from the induction heating unit 25 shown in FIG. 4 and taken out from the image forming apparatus main body 1 with the door 100 opened. (This is a movement in the right direction in FIG. 1).

The fixing device 19 configured as described above operates as follows.
The fixing roller 20 is driven to rotate counterclockwise in FIG. 2 by a drive motor (not shown), and the pressure roller 30 is rotated clockwise accordingly. The sleeve layer 21 (heat generation layer) of the fixing roller 20 is heated by the magnetic flux generated from the induction heating unit 25 at a position facing the induction heating unit 25.

  Specifically, the excitation circuit is energized by applying a high frequency alternating current of 10 kHz to 1 MHz (preferably 20 kHz to 800 kHz) to the excitation coil 26 from a power supply unit (not shown) whose frequency is variable. The magnetic field lines are alternately switched in both directions from 26 toward the sleeve layer 21 of the fixing roller 20. By forming an alternating magnetic field in this manner, an eddy current is generated in the heat generating layer of the sleeve layer 21, and the heat generating layer generates Joule heat due to its electric resistance and is induction-heated. Thus, the sleeve layer 21 (fixing roller 20) is heated by induction heating of its own heat generation layer.

Thereafter, the surface of the fixing roller 20 heated by the induction heating unit 25 reaches a contact portion (nip portion) with the pressure roller 30. Then, the toner image T (toner) on the conveyed recording medium P is heated and melted.
Specifically, the recording medium P carrying the toner image T through the image formation process described above is guided between the entrance guide plate 41 (or the spur guide plate 42) and between the fixing roller 20 and the pressure roller 30 ( (It is a nip portion)) (the movement in the transport direction of the arrow Y1). The toner image T is fixed on the recording medium P by the heat received from the fixing roller 20 and the pressure received from the pressure roller 30, and the recording medium P is sent out between the fixing roller 20 and the pressure roller 30 ( This is the movement in the transport direction of the arrow Y2.)
The surface of the fixing roller 20 that has passed through the nip portion then reaches the position facing the induction heating unit 25 again.
Such a series of operations is continuously repeated to complete the fixing step in the image forming process.

Hereinafter, the toner used in the image forming apparatus according to the first embodiment will be described in detail.
In the first exemplary embodiment, the toner T contains paraffin wax having a melting point in the range of 60 to 90 ° C. Specifically, the toner T has base particles containing a paraffin wax having a melting point of 60 ° C. or higher and 90 ° C. or lower and a binder resin, and the base particles are absorbed by the paraffin wax having an endothermic peak in DSC measurement. The heat amount is 3.5 J / g or more and 5.5 J / g or less, and the average circularity is 0.950 or more and 0.980 or less. In this way, the toner T contains paraffin wax having a melting point in the range of 60 to 90 ° C., thereby improving the low-temperature fixability and fixing roller 20 or pressure roller 30 without applying oil to fixing roller 20. The separation property (release property) of the recording medium P can be improved. In particular, as compared with the case where the toner contains other wax (for example, carnauba wax, rice wax, polyethylene wax, polyolefin wax, etc.), the separability (release property) of the recording medium P with respect to the fixing roller 20 and the like. ) Can be increased. In the first embodiment, the melting point of the paraffin wax contained in the toner T is set to 67 ° C.

Hereinafter, the toner T will be described in more detail.
(Particle size distribution)
In order to reproduce minute dots of 600 dpi or more, the toner preferably has a weight average particle diameter (D4) of 3 to 8 μm. The ratio (D4 / Dn) of the weight average particle diameter (D4) to the number average particle diameter (Dn) is preferably in the range of 1.00 to 1.30. The closer the (D4 / Dn) is to 1.00, the sharper the particle size distribution. For the same reason, it is preferable that 1 to 10% by number of particles of 2 μm or less. Such a toner having a small particle size and a narrow particle size distribution makes the toner charge amount distribution uniform and can provide a high-quality image with little background fogging. In addition, the electrostatic transfer system has a high development efficiency. can do. On the other hand, the problem when reducing the toner particle size is that the non-electrostatic adhesion to the carrier is larger than that of the larger particle size, so it stays on the carrier surface for a long time and is easily subjected to agitation stress and adheres to the carrier surface. It causes the charging ability of the carrier to decrease. In order to prevent such a problem, the number of particles having a size of 2 μm or less is preferably 1 to 10% by number.

Here, the particle size distribution of the toner particles is measured by the Coulter counter method. Examples of the measuring device by the Coulter counter method include Coulter counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below.
First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2-20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. Volume distribution and number distribution are calculated. From the obtained distribution, the weight average particle diameter (D4) and the number average particle diameter of the toner can be obtained.
As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

(FPIA, average circularity, aspect ratio)
For measurement of ultra-fine toner having an aspect ratio, average circularity of 2 μm or less, measurement is performed using a flow type particle image analyzer (FPIA-3000; manufactured by Sysmex Corporation), and analysis is performed using analysis software attached to the same machine. It was. Specifically, 0.1 to 0.5 ml of 10 wt% surfactant (alkylbenzene sulfonate Neogen SC-A; Daiichi Kogyo Seiyaku) is added to a glass 100 ml beaker, and each toner 0.1 to 0 is added. 0.5 g was added and stirred with a microspatel, and then 80 ml of ion-exchanged water was added. The obtained dispersion was subjected to a dispersion treatment for 3 minutes with an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.). Using the FPIA-3000, the dispersion was measured for toner shape and distribution until a density of 5000 to 15000 / μl was obtained. In this measurement method, it is important that the concentration of the dispersion liquid is 5000 to 15000 / μl from the viewpoint of measurement reproducibility of the average circularity. In order to obtain the dispersion concentration, it is necessary to change the conditions of the dispersion, that is, the amount of surfactant to be added and the amount of toner. The amount of the surfactant varies depending on the hydrophobicity of the toner as in the measurement of the toner particle diameter described above, and if it is added in a large amount, noise due to bubbles is generated. If the amount is too small, the toner cannot be sufficiently wetted and dispersion is not achieved. It will be enough. Further, the toner addition amount differs from the particle size, and it is necessary to decrease the small particle size and increase the large particle size. When the toner particle size is 3 to 7 μm, the toner amount is 0.1 to 0. By adding 0.5 g, the dispersion concentration can be adjusted to 5000 to 15000 / μl.
As analysis conditions, an aspect ratio and an average circularity obtained by analyzing the measurement target particle size limit of 2 to 200 μm and the amount of super fine toner of 2 μm or less were obtained. The average circularity and aspect ratio are defined as follows.
Average circularity = (salt circumference equal to particle area) / (particle circumference)
Aspect ratio = (Maximum vertical length) / (Maximum length)
The average circularity is a shape factor that mainly expresses the degree of unevenness of particles, whereas the aspect ratio is a shape factor that mainly expresses the acicularity of particles.

The relationship between the toner shape and the cleaning property (which is the cleaning property in the cleaning unit 15) was evaluated, and it was found that the shape (particularly the aspect ratio) has a close correlation with the cleaning characteristics. In the toner having a small aspect ratio, the interaction force between the toner particles under the compacting condition is large, and the transfer residual toner on the photosensitive drum is damped by the blade in the process of damping (cleaning) the toner with a cleaning blade or the like. The toner tends to aggregate and form a toner layer. Accordingly, the transfer residual toner is blocked not only by the blade but also by the toner layer blocked by the blade, and the amount of toner passing through the cleaning blade is reduced, so that a good cleaning property can be obtained.
When the toner has an aspect ratio of greater than 0.90, the cleaning property is deteriorated. On the other hand, when the aspect ratio is less than 0.80, a trouble caused by low fluidity in a process other than cleaning, specifically, in a pipe Problems such as toner clogging become significant. For this reason, the aspect ratio has an optimum range, and its value is 0.80 to 0.90.

As a problem that has not been found so far, in the process of charging and developing the toner, it has been found that the following tendencies (1) to (4) exist between the shape of the toner and the charging characteristics.
(1) The closer the toner shape is to a sphere, the more likely the toner and the carrier are in point contact, or the toner contacts while rotating on the carrier, so that the toner easily rolls on the surface of the carrier, paraffin wax, low molecular weight A toner component such as a resin component is easily fixed on the carrier. As a result, the charging ability of the carrier is easily lowered. This corresponds to a small contact area between the toner and the carrier (two-component development method) and a small contact area between the toner and the developing sleeve (one-component development method).
(2) On the other hand, when the surface shape of the toner is rough and there are many irregularities, the toner and the carrier are in surface contact, so that the toner is difficult to roll on the surface of the carrier, but the contact area between the toner and the carrier is large, and the paraffin wax In addition, toner components such as low molecular weight resin components are easily fixed on the carrier. As a result, the charging ability of the carrier is easily lowered. This corresponds to a large contact area between the toner and the carrier (two-component development method) and a large contact area between the toner and the developing sleeve (one-component development method).
(3) When the toner and the carrier are stirred for a long time, the influence of the shape appears more strongly than the unevenness. In other words, when the toner and the carrier are stirred in the developing machine for a long time in durability evaluation under actual use conditions, the unevenness on the toner is scraped or deformed, so that the unevenness does not remain. The effect of 1) appears.
(4) For this reason, it is preferable to look at the toner shape related to the chargeability of the toner, especially the decrease in the charging ability of the carrier due to long-term agitation. The lower the aspect ratio, the more difficult it is to roll on the carrier. The higher the value, the closer to the spherical shape, so it is easier to roll on the carrier. Therefore, it is preferable that the aspect ratio of the range in which the toner component is not fixed on the carrier while maintaining a proper contact between the toner and the carrier is in the range of 0.80 to 0.90.

  From the above points, the toner aspect ratio has an optimum range, and its value is 0.80 to 0.90. However, when looking at transfer performance as a new issue, the greater the torque evaluated by this torque evaluation method, the more likely the worm-eating phenomenon occurs during transfer, so the surface properties of the photosensitive drum and intermediate transfer belt, specifically It is necessary to optimize the surface friction coefficient, and it has been found that good results can be obtained in any of the cleanability, developability, and transferability that are trade-offs.

(SF-1, SF-2)
It is preferable that the shape factor SF-1 of the toner is in the range of 130 to 160, and the shape factor SF-2 is in the range of 110 to 140.
The shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (1). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) ² / AREA} × (100π / 4) .. Formula (1)
When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases.

The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner onto the two-dimensional plane by the figure area AREA and multiplying by 100 / 4π.
SF-2 = {(PERI) ² / AREA} × (100 / 4π) .. Formula (2)
When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent.

Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.) and introducing it into an image analyzer (LUSEX3: manufactured by Nireco). 100 pieces were analyzed and calculated.
When a toner having D / S of 15 to 40% and (L / M)> 2 is expressed by SF-1 and SF-2, SF-1 is in the range of 130 to 160, and the shape factor SF-2 is 110 to 110. It is in the range of 140.

(Toner density)
In a full-color image forming apparatus, the toner concentration in the developer is often used in a toner concentration range of 3 to 12 wt%. The image density is controlled in consideration of the particle size of the toner and the carrier in the developer, that is, the surface area, and the occupied area of the toner to be tightened to the carrier surface area is controlled to be 100% or less. This is a measure for maintaining contact and preventing insufficient charging of the toner due to poor contact between the toner and the carrier. Here, in the developer having a high toner concentration, there is a problem that a low melting point wax, a resin or the like in the toner is fixed on the carrier surface and the charging ability of the carrier is lowered.

(Endothermic peak endotherm derived from release agent by DSC)
The glass transition point (Tg) of the toner is usually 40 to 70 ° C., preferably 40 to 60 ° C. If it is less than 40 ° C., the heat resistance of the toner deteriorates, and if it exceeds 70 ° C., the low-temperature fixability becomes insufficient. Due to the coexistence of a modified polyester such as a urea-modified polyester resin, the toner of the present invention tends to have good heat-resistant storage stability even when the glass transition point is low, as compared with known polyester-based toners.
Further, in order to obtain hot offset resistance among the fixing performance, it is preferable that the release material is large. On the other hand, since the release agent is easily fixed to the carrier, in order to maintain the charging ability of the developer carrier for a long period of time. Less is preferred. From this point of view, the content of the release agent in the toner is excellent in hot offset resistance in that the endothermic amount of the endothermic peak derived from the release agent in DSC is in the range of 3.5 to 5.5 J / g. This is desirable in terms of maintaining the charging ability of the carrier. In the first embodiment, as described above, paraffin wax having a melting point in the range of 60 to 90 ° C. is used as the release agent to be contained in the toner T.

Using Shimadzu TA-60WS and DSC-60 as measuring devices, the measurement was performed under the following measurement conditions.
・ Measurement conditions Sample container: Aluminum sample pan (with lid)
Sample amount: 5mg
Reference: Aluminum sample pan (alumina 10mg)
Atmosphere: Nitrogen (flow rate 50 ml / min)
Temperature conditions Starting temperature: 20 ° C
Temperature increase rate: 10 ° C / min
End temperature: 150 ° C
Holding time: None Temperature drop: 10 ° C / min
End temperature: 20 ° C
Holding time: None Temperature increase rate: 10 ° C / min
End temperature: 150 ° C

The measurement results were analyzed using the data analysis software (TA-60, version 1.52) manufactured by Shimadzu Corporation. In the analysis method, the DrDSC curve, which is the DSC differential curve of the second temperature rise, specifies two locations on the low-temperature side and high-temperature side of the endothermic peak corresponding to the endotherm when the release agent melts. The peak endotherm is obtained using the peak analysis function. The endothermic peak corresponding to the endotherm at the time of melting of the release agent is an endothermic peak obtained by performing DSC measurement of the release agent alone by the above procedure.
In addition, the toner Tg is designated with a range of ± 5 ° C. around the point showing the maximum peak on the lowest temperature side of the DrDSC curve, which is the DSC differential curve of the second temperature increase, and is peaked using the peak analysis function of the analysis software. Find the temperature. Next, the maximum endothermic temperature of the DSC curve is determined using the peak analysis function of the analysis software in the range of the peak temperature + 5 ° C. and −5 ° C. in the DSC curve. The temperature shown here corresponds to the Tg of the toner.

Other toner constituent materials will be described.
-Modified polyester-
The toner of the present invention contains a modified polyester (i) as a binder resin. The modified polyester (i) refers to a state in which a bonding group other than an ester bond is present in the polyester resin, or resin components having different configurations are bonded to the polyester resin by a covalent bond, an ionic bond, or the like. Specifically, the polyester terminal is modified by introducing a functional group such as a carboxylic acid group or an isocyanate group that reacts with a hydroxyl group into the polyester terminal and further reacting with an active hydrogen-containing compound.

  Examples of the modified polyester (i) include urea-modified polyester obtained by a reaction between a polyester prepolymer (A) having an isocyanate group and amines (B). As the polyester prepolymer (A) having an isocyanate group, a polyester having a polycondensate of a polyhydric alcohol (PO) and a polyvalent carboxylic acid (PC) and having an active hydrogen group is further added to a polyvalent isocyanate compound (PIC). And those reacted with. Examples of the active hydrogen group possessed by the polyester include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, and the like. Among these, an alcoholic hydroxyl group is preferable.

The urea-modified polyester is produced as follows.
Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable. Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among these, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. As trihydric or higher polyhydric alcohol (TO), trihydric or higher polyhydric aliphatic alcohol (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

  Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) and a small amount of (TC) Mixtures are preferred. Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

  The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.

  The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.

The content of the polyvalent isocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40% by mass, preferably 1 to 30% by mass, more preferably 2 to 20% by mass. %. If it is less than 0.5% by mass, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40% by mass, the low-temperature fixability deteriorates.
The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

Next, as amines (B) to be reacted with the polyester prepolymer (A), a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4) ), Amino acids (B5), and (B6) in which the amino group of (B1) to (B5) is blocked.
Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.).
Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine.
Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline.
Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan.
Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid.
As (B6) which blocked the amino group of (B1) to (B5), ketimine compounds obtained from the amines and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.) of (B1) to (B5), And oxazolidine compounds.
Among these amines (B), preferred are (B1) and a mixture of (B1) and a small amount of (B2).
The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated.
The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

The modified polyester (i) is produced by a one-shot method or a prepolymer method. The weight average molecular weight of the modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, more preferably 30,000 to 1,000,000. The peak molecular weight at this time is preferably 1000 to 10000. When the molecular weight is less than 1000, the elongation reaction hardly occurs, the elasticity of the toner is small, and as a result, the resistance to hot offset deteriorates. On the other hand, when it exceeds 10,000, the problem in production becomes high in the deterioration of fixability, particle formation and pulverization. The number average molecular weight of the modified polyester (i) is not particularly limited when the unmodified polyester (ii) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. (I) When used alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, and more preferably 2000 to 8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color device are deteriorated.
In the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B) to obtain the modified polyester (i), a reaction terminator is used as necessary to adjust the molecular weight of the resulting urea-modified polyester. be able to. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those blocked (ketimine compounds).

-Unmodified polyester-
Not only the modified polyester (i) can be used alone, but also this (i), unmodified polyester (ii) can be contained as a binder resin component. By using (ii) in combination, the low-temperature fixability and the gloss when used in a full-color device are improved, which is preferable to single use. Examples of (ii) include polycondensates of polyhydric alcohol (PO) and polyvalent carboxylic acid (PC) similar to the polyester component of (i) above, and preferred ones are also the same as (i). . (Ii) is not limited to unmodified polyester, but may be modified with a chemical bond other than a urea bond, and may be modified with a urethane bond, for example. It is preferable that (i) and (ii) are at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Accordingly, the polyester component (i) and (ii) preferably have similar compositions. When (ii) is contained, the weight ratio of (i) and (ii) is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, Particularly preferred is 7/93 to 20/80. If the weight ratio of (i) is less than 5%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The peak molecular weight of (ii) is usually 1000 to 10,000, preferably 2000 to 8000, and more preferably 2000 to 5000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 10,000, low-temperature fixability will deteriorate. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. The acid value of (ii) is preferably 1 to 5, more preferably 2 to 4. Since a high acid value wax is used as the wax, the low acid value binder leads to electrification and high volume resistance, so that it is easy to match the toner used for the two-component developer.

  The glass transition point (Tg) of the binder resin is usually 35 to 70 ° C., preferably 40 to 65 ° C., more preferably 40 to 60 ° C. when toner particles containing other toner materials are used. If it is less than 35 ° C., the heat resistant storage stability of the toner is deteriorated, and if it exceeds 70 ° C., the low-temperature fixability becomes insufficient. Since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the toner of the present invention tends to have good heat storage stability even when the glass transition point is low, as compared with known polyester-based toners. Show.

-Colorant-
As the colorant, known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, Yellow lead, Titanium yellow, Polyazo yellow, Oil yellow, Hansa yellow (GR, A, RN, R), Pigment yellow L, Benzidine yellow (G, GR), Permanent yellow (NCG), Vulcan fast yellow (5G, R) ), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Se Red, parachlor ortho nitroa Lynn Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carnmin BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R , Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Po Azo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalo Anine green, anthraquinone green, titanium oxide, zinc white, lithopone and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by mass, preferably 3 to 10% by mass with respect to the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded together with the production of the master batch or the master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.

  The masterbatch can be obtained by mixing and kneading a masterbatch resin and a colorant under high shear. In this case, an organic solvent can be used in order to enhance the interaction between the colorant and the resin. In addition, a so-called flushing method, which is a wet cake of a colorant, is a method of mixing and kneading an aqueous paste containing water of a colorant together with a resin and an organic solvent, transferring the colorant to the resin side, and removing moisture and organic solvent components. Since it can be used as it is, it does not need to be dried and is preferably used. For mixing and kneading, a high shear dispersion device such as a three-roll mill is preferably used.

-Charge control agent-
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salt or compound, tungsten simple substance or compound, fluorine-based activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSYVP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (manufactured by Nippon Carlit) ), Copper phthalocyanine, perylene, quinacridone, azo face And other polymeric compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of the charge control agent used is determined based on the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the binder resin. Preferably, the range of 0.2-5 mass parts is good. When the amount exceeds 10 parts by mass, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

―Inorganic filler―
As the inorganic filler for controlling the toner shape, montmorillonite or an organic modified product thereof (Clayton APA) is used. The function of the inorganic filler is to form irregularities on the toner surface, and the mechanism is as follows.
In a toner manufacturing method in which a toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles, the inorganic filler in the toner material liquid moves to the interface between the organic solvent and the aqueous solvent during emulsification, and the emulsion dispersion Collect on the surface shape of the (reactant). Next, in the step of removing the organic solvent from the emulsified dispersion (reactant), washing and drying, the inorganic filler present on the surface forms irregularities on the surface of the reaction product. Therefore, in obtaining the shape of the present invention, the amount of the inorganic filler can be controlled within the range of 0.1 to 10 parts by weight to change the shape, and the larger the amount of the inorganic filler, the more SF-1 and SF-2. The value of becomes larger and deforms.

-External additive-
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × 10 −3 to 0.3 μm. Moreover, it is preferable that the specific surface area by BET method is 100-500 m <2> / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5% by mass of the toner, and particularly preferably 0.01 to 2.0% by mass.
Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.
In addition, polymer fine particles, such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization, and dispersion polymerization, methacrylic acid ester, acrylic acid ester copolymer, polycondensation system such as silicone, benzoguanamine, nylon, thermosetting Examples thereof include polymer particles made of a resin.

Such external additives can be surface-treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .
In particular, it is preferable to use hydrophobic silica and hydrophobic titanium oxide obtained by subjecting silica and titanium oxide to the above surface treatment.

Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.
(Production method of toner binder)
The toner binder can be manufactured by the following method. Polyhydric alcohol (PO) and polyvalent carboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and water generated while reducing the pressure as necessary. Distill off to obtain a polyester having a hydroxyl group. Subsequently, at 40-140 degreeC, this is made to react with a polyvalent isocyanate compound (PIC), and the prepolymer (A) which has an isocyanate group is obtained. Further, (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a polyester modified with a urea bond.
When reacting (PIC) and when reacting (A) and (B), a solvent may be used if necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers Inactive to polyvalent isocyanate compounds (PIC) such as benzene (such as tetrahydrofuran).
When the unmodified polyester (ii) is used in combination, (ii) is produced by the same method as that for the polyester having a hydroxyl group, and this is dissolved and mixed in the solution after completion of the reaction (i).

(Toner production method)
1) A toner material liquid is prepared by dispersing a colorant, unmodified polyester (i), a polyester prepolymer (A) having an isocyanate group, and a release agent in an organic solvent. The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform and carbon tetrachloride are preferred. The usage-amount of an organic solvent is 0-300 mass parts normally with respect to 100 mass parts of polyester prepolymers, Preferably it is 0-100 mass parts, More preferably, it is 25-70 mass parts.

2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.
The amount of the aqueous medium used relative to 100 parts by mass of the toner material liquid is usually 50 to 2000 parts by mass, preferably 100 to 1000 parts by mass. If the amount is less than 50 parts by mass, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 2000 parts by mass, it is not economical.

The glass transition point (Tg) of the resin fine particles dispersed in the aqueous medium is preferably 50 to 110 ° C., more preferably 50 to 90 ° C. When the glass transition point (Tg) is less than 50 ° C., toner storage stability is obtained. Or the probability of fixing and aggregation in the toner recovery path during recycling increases. When the glass transition point (Tg) is higher than 110 ° C., the resin fine particles hinder the adhesion to the fixing paper, and the fixing minimum temperature is increased. A more preferred range is a range of 50 to 70 ° C.
The weight average molecular weight is desirably 100,000 or less. Preferably it is 50,000 or less. The lower limit is usually 4000. When the weight average molecular weight exceeds 100,000, the resin fine particles inhibit the adhesiveness with the fixing paper, and the minimum fixing temperature increases.

  As the resin fine particles, known resins can be used as long as they can form an aqueous dispersion, and thermoplastic resins or thermosetting resins may be used. Examples thereof include vinyl resins, polyurethane resins, epoxy resins, and polyester resins. It is done. As the resin fine particles, two or more of the above resins may be used in combination. Among these, those made of a vinyl resin, a polyurethane resin, an epoxy resin, a polyester resin, or a combination resin thereof are preferable because an aqueous dispersion of fine spherical resin particles is easily obtained.

Vinyl resins are polymers obtained by homopolymerization or copolymerization of vinyl monomers, such as styrene-acrylic acid ester resins, styrene-methacrylic acid ester resins, styrene-butadiene copolymers, acrylic acid-acrylic acid ester polymers. Methacrylic acid-acrylic acid ester polymer, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, and the like.
In the resin fine particles, the volume average particle diameter is a value measured with a light scattering photometer (manufactured by Otsuka Electronics), and is 10 to 200 nm, preferably 20 to 80 nm.
Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.
As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride, fatty acid amide derivative, polyhydric alcohol Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.
Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

  In addition, examples of the cationic surfactant include aliphatic quaternary ammonium salts such as aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, and perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts. Benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, trade names include Surflon S-121 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.), Unidyne DS-202 (Daikin Industries) Manufactured), MegaFuck F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footgent F-300 (Neos), and the like.

The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium or to prevent the wax from being exposed to the outermost surface of the toner. For this reason, it is preferable to add so that the coverage existing on the surface of the toner base particles is in the range of 10 to 90%.
In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

  As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxypropyl , 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl imidazole , Nitrogen-containing compounds such as ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, polyoxypro Len, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene Polyoxyethylenes such as nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

3) At the same time as the preparation of the emulsion, the amines (B) are added to react with the polyester prepolymer (A) having an isocyanate group.
This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles.
In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent-based toner base particles can be produced by removing the solvent. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner.
The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like.
Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

Hereinafter, the configuration and operation of the fixing device 19 which are characteristic in the first embodiment will be described in detail.
Referring to FIG. 5, fixing device 19 according to the first exemplary embodiment has a non-facing surface in which wettability (wetting with paraffin wax) on facing surface 28 a of coil guide 28 does not face fixing roller 20 ( It is formed so as to be better than the wettability (the wettability with respect to paraffin wax) in the surface 28b or the like facing the exciting coil 26). Specifically, it is formed so that the surface roughness of the facing surface 28a is rougher than the surface roughness of the non-facing surface 28b.

  Specifically, when paraffin wax Q is attached to the facing surface 28a of the coil guide 28, the paraffin wax Q diffuses as shown in FIG. 6A, whereas the paraffin wax Q spreads on the non-facing surface 28b of the coil guide 28. When the paraffin wax Q is adhered, the paraffin wax Q aggregates as shown in FIG. That is, the angle θ (a parameter representing the degree of wettability) formed between the paraffin wax Q and the facing surface 28a when the paraffin wax Q is attached to the facing surface 28a of the coil guide 28 is a coil. When the paraffin wax Q is attached to the non-facing surface 28b of the guide 28, the angle θ is smaller than the angle θ formed between the paraffin wax Q and the non-facing surface 28b.

With this configuration, when a toner containing paraffin wax having a low melting point (in the range of 60 to 90 ° C.) is used, the paraffin wax volatilizes at the position of the nip portion, the surface of the fixing roller 20, and the like. Even if the volatilized paraffin wax adheres to the facing surface 28a of the induction heating unit 25 (coil guide 28) facing the fixing roller 20, the paraffin wax adheres to the facing surface 28a due to good wettability of the facing surface 28a. Since it diffuses in all directions, the problem of paraffin wax locally sticking and accumulating on the opposing surface 28a can be suppressed.
That is, paraffin wax adheres and accumulates on the opposing surface 28a of the induction heating unit 25 (coil guide 28) (adhering to a position surrounded by a broken line in FIGS. 2 and 4), and the accumulated paraffin is accumulated. When the height of the wax exceeds a minute gap (about 2 mm) between the fixing roller 20 and the facing surface 28a, a part of the paraffin wax fixed to the induction heating unit 25 adheres to the fixing roller 20. . Then, the paraffin wax adhering to the fixing roller 20 adheres onto the recording medium P at the position of the nip portion during the fixing process, and a “wax adhesion image” is output. On the other hand, in the first embodiment, since the wettability of the facing surface 28a of the coil guide 28 facing the fixing roller 20 is improved, the paraffin wax adhering to the facing surface 28a diffuses and faces the facing surface 28a. The problem of paraffin wax locally sticking and accumulating on the surface 28a can be suppressed.

Here, in the first embodiment, with reference to FIG. 5, the facing surface 28a, the surface portion 28c connected to the lower end of the facing surface 28a, and the surface portion 28d connected to the upper end of the facing surface 28a are rough. A rough surface portion 28a1 (a surface having good wettability) is formed.
Referring to FIG. 7, the opposing surface 28a of the coil guide 28 has at least a width direction range X2 (range in the width direction of the rough surface portion 28a1) formed so as to improve wettability to paraffin wax. It is formed so as to include a range X1 in the width direction of the maximum recording medium P capable of passing paper. Of the opposing surface 28a of the coil guide 28, the range in the width direction to which the paraffin wax adheres substantially coincides with the range X1 in the width direction of the maximum recording medium P that can be passed through, so that the range X1 is included. By defining the range X2 in the width direction of the rough surface portion 28a1, the occurrence of the “wax adhesion image” can be reliably suppressed.

The rough surface portion 28a1 of the coil guide 28 (having good wettability to paraffin wax) is formed by subjecting the coil guide 28 to injection molding and then sandblasting the portion where the rough surface portion 28a1 is to be formed. be able to.
In addition, the rough surface portion 28a1 of the coil guide 28 can be formed by subjecting the portion where the rough surface portion 28a1 is to be formed to the same time as the coil guide 28 is injection-molded. That is, the rough surface portion 28a1 can be formed by roughening the surface of a part of the mold of the coil guide 28 (where the rough surface portion 28a1 is desired to be formed).
The surfaces other than the rough surface portion 28a1 of the coil guide 28 (non-facing surfaces such as the surface 28b facing the exciting coil 26) are not subjected to the above-described sandblasting or embossing, and the coil guide 28 is injected. It has the same surface roughness after being molded.

Thus, the surface roughness of the facing surface 28a of the coil guide 28 is formed so as to be rougher than the surface roughness of the non-facing surface (such as the surface 28b facing the exciting coil 26). FIG. 8A is a diagram showing a surface roughness profile of the facing surface 28a, and FIG. 8B is a diagram showing a surface roughness profile of the non-facing surface 28b.
In order to ensure the effect of diffusing the paraffin wax, the opposing surface 28a (rough surface portion 28a1) of the coil guide 28 has an arithmetic average roughness (Ra) of 3 μm or more, or a ten-point average roughness (Rz). ) Is preferably 15 μm or more. In the first embodiment, the rough surface portion 28a1 is formed so that the arithmetic average roughness (Ra) is about 5 μm and the ten-point average roughness (Rz) is about 25 μm. Further, portions other than the rough surface portion 28a1 (non-facing surfaces that are not subjected to sandblasting or graining) have an arithmetic average roughness (Ra) of about 0.24 μm and a ten-point average roughness. (Rz) is formed to be about 1.2 μm.

In the first embodiment, the rough surface portion 28a1 is formed on the facing surface 28a, the surface portion 28c connected to the lower end of the facing surface 28a, and the surface portion 28d connected to the upper end of the facing surface 28a (see FIG. 5). ).
On the other hand, as shown in FIG. 9, the rough surface portion 28a1 can be formed on the facing surface 28a and the surface portion 28c connected to the lower end of the facing surface 28a. That is, the wettability (surface roughness) of the surface portion 28c connected to the lower end of the opposing surface 28a can be formed to be equivalent to the wettability (surface roughness) of the opposing surface 28a. As described above, the sticking / accumulation of paraffin wax mainly occurs in the vicinity of the lower end of the facing surface 28a (the region surrounded by the broken line in FIGS. 2 and 4). Even if the rough surface portion 28a1 is formed only on the surface portion 28c connected to the lower end of the facing surface 28a, the occurrence of “wax adhesion image” can be sufficiently suppressed.

It is noted that the paraffin wax adhering to the facing surface 28a is likely to adhere and accumulate near the lower end of the facing surface 28a (a region surrounded by a broken line in FIGS. 2 and 4). It is because it is arrange | positioned by the side. Specifically, referring to FIG. 2, fixing is performed such that a line segment H connecting the vertical center O of the facing surface 28a of the induction heating unit 25 and the rotation center O ′ of the fixing roller 20 is substantially horizontal. A device 19 is configured. With such a configuration, the paraffin wax adhering to the facing surface 28a flows in the vicinity of the lower end of the facing surface 28a (a region surrounded by a broken line in FIGS. 2 and 4) and adheres and accumulates according to the gravity. It becomes easy to do. However, in FIG. 9, since the rough surface portion 28a1 is formed on the facing surface 28a and the surface portion 28c connected to the lower end of the facing surface 28a, the flow of paraffin wax in the gravitational direction is suppressed, In order to diffuse around the position adhering to the surface, it is possible to suppress the problem that the paraffin wax locally adheres and accumulates.
Further, even when the posture of the induction heating unit 25 with respect to the fixing roller 20 is changed (for example, when the induction heating unit 25 is disposed above the fixing roller 20), it volatilizes and forms the opposing surface 28a. The adhering paraffin wax tends to flow along the facing surface 28a according to the gravity, but the rough surface portion 28a1 is formed on the facing surface 28a and the vicinity thereof to suppress the flow of the paraffin wax in the gravity direction. In addition, since the paraffin wax diffuses around the position where the paraffin wax first adheres, it is possible to suppress a problem that the paraffin wax locally adheres and accumulates.

  As described above, in the first embodiment, the coil guide 28 of the induction heating unit 25 is formed so that the wettability with respect to the paraffin wax on the facing surface 28a facing the fixing roller 20 (fixing member) is improved. Therefore, even when a toner containing paraffin wax having a melting point in the range of 60 to 90 ° C. is used, it is possible to suppress a problem that a “wax adhesion image” is generated on a recording medium to be printed. it can.

Embodiment 2. FIG.
A second embodiment of the present invention will be described in detail with reference to FIG.
FIG. 10 is a cross-sectional view showing the fixing device in the second embodiment, and corresponds to FIG. 2 in the first embodiment. The fixing device in the second embodiment is different from that in the first embodiment in which the fixing roller 65 is used as a fixing member in that the fixing belt 65 is used as a fixing member.

  As shown in FIG. 10, the fixing device 20 according to the second embodiment includes an induction heating unit 25, a fixing belt 65 as a fixing member, a heating roller 66, a fixing auxiliary roller 67, a pressure roller 30 as a pressure member, Etc.

Here, the fixing auxiliary roller 67 is formed by forming an elastic layer such as silicone rubber on the surface of a cored bar made of stainless steel or the like. The elastic layer of the fixing auxiliary roller 67 has a thickness of 1 to 10 mm and an Asker hardness of 30 to 60 degrees.
The heating roller 66 is a cylindrical body formed of stainless steel or the like. The heating roller 66 and the auxiliary fixing roller 67 rotate counterclockwise in FIG.
The fixing belt 65 including the heat generating layer is stretched and supported by a heating roller 66 and a fixing auxiliary roller 67. The fixing belt 65 has a base layer, an elastic layer, a heat generation layer, a silicone rubber layer, and a release layer laminated from the inner peripheral surface side. The heat generating layer of the fixing belt 65 is heated by electromagnetic induction by the magnetic flux generated from the induction heating unit 25.
Also in the second embodiment, as in the first embodiment, the wettability of the facing surface of the coil guide 28 (the facing surface facing the fixing belt 65) is the non-facing surface (the fixing belt 65). It is a surface that does not face the surface.) Wetability is better.

The fixing device 19 configured in this way operates as follows during the fixing process.
By the rotation driving of the fixing auxiliary roller 67, the fixing belt 65 rotates counterclockwise in FIG. 10, the heating roller 66 also rotates counterclockwise, and the pressure roller 30 also rotates clockwise. The fixing belt 65 is heated at a position facing the induction heating unit 25.
Specifically, by supplying a high-frequency alternating current of 10 kHz to 1 MHz (preferably 20 kHz to 800 kHz) from the power supply unit (not shown) to the coil unit 25, the magnetic field lines are alternately switched in both directions toward the heat generating layer. Formed. By forming the alternating magnetic field in this manner, an eddy current is generated in the heat generating layer of the fixing belt 65, Joule heat is generated by the electric resistance of the heat generating layer, and the heat generating layer is heated. In this way, the fixing belt 65 is heated by the heat generated by its own heat generating layer.

  Thereafter, the surface of the fixing belt 65 heated by the induction heating unit 25 reaches a contact portion with the pressure roller 30. Then, the toner image T (toner) on the conveyed recording medium P is heated and melted. The surface of the fixing belt 65 that has passed through the nip portion then reaches the position facing the induction heating unit 25 again. Such a series of operations is continuously repeated to complete the fixing step in the image forming process.

  In the second embodiment, the heat generating layer heated by induction by the induction heating unit 25 is provided on the fixing member (fixing belt 65). However, the heat generating layer may be provided on the heating roller 66. In such a case, the heating roller 66 is heated by electromagnetic induction by the induction heating unit 25, and the fixing belt 65 is indirectly heated by the heating roller 66.

  As described above, also in the second embodiment, as in the first embodiment, the induction heating section is improved so that the wettability to paraffin wax on the facing surface 28a facing the fixing belt 65 (fixing member) is improved. Even when a toner containing paraffin wax having a melting point in the range of 60 to 90 ° C. is used because the 25 coil guides 28 are formed, the “wax adhesion image” is printed on the printed recording medium. ”Can be prevented.

  In each of the above embodiments, the present invention is applied to a fixing device using the fixing roller 20 or the fixing belt 65 as a fixing member and the pressure roller 30 as a pressure member. The present invention can also be applied to an electromagnetic induction heating type fixing device using the above and an electromagnetic induction heating type fixing device using a pressure belt or a pressure pad as a pressure member. In such a case, the same effects as those of the above embodiments can be obtained.

  It should be noted that the present invention is not limited to the above-described embodiments, and within the scope of the technical idea of the present invention, the embodiments can be modified as appropriate in addition to those suggested in the embodiments. Is clear. In addition, the number, position, shape, and the like of the constituent members are not limited to the above embodiments, and can be set to a number, position, shape, and the like that are suitable for carrying out the present invention.

1 is an overall configuration diagram illustrating an image forming apparatus according to Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view illustrating a fixing device. FIG. 3 is a perspective view illustrating a part of the fixing device. It is a perspective view which shows the induction heating part of a fixing device. It is a figure which shows the range of the rough surface part of a coil guide. It is the schematic which shows the state of the paraffin wax adhering to a coil guide. It is a front view which shows a coil guide in the width direction. It is a figure which shows the surface roughness profile of a coil guide. It is a figure which shows the range of the rough surface part of another coil guide. It is sectional drawing which shows the fixing device in Embodiment 2 of this invention.

Explanation of symbols

1 image forming apparatus body (apparatus body),
19 fixing device,
20 fixing roller (fixing member),
25 induction heating unit,
26 Excitation coil,
28 Coil guide,
28a facing surface,
28a1 rough surface portion (surface with good wettability),
28b coil holding surface,
30 pressure roller (pressure member),
65 fixing belt (fixing member),
66 heating roller,
67 Fixing auxiliary roller, Q Paraffin wax.

Claims (7)

A fixing member that heats and melts the toner to fix it on the recording medium;
An induction heating unit for directly or indirectly heating the fixing member by electromagnetic induction;
With
The toner contains paraffin wax having a melting point in the range of 60 to 90 ° C.,
The induction heating unit includes a coil guide that faces the outer peripheral surface of the fixing member and holds an exciting coil,
The coil guide is formed such that the wettability with respect to the paraffin wax on the facing surface facing the fixing member is better than the wettability with respect to the paraffin wax on the non-facing surface not facing the fixing member. A fixing device.   The fixing device according to claim 1, wherein the coil guide is formed such that a surface roughness of the facing surface is larger than a surface roughness of the non-facing surface.   3. The fixing according to claim 2, wherein the opposed surface of the coil guide is formed so that an arithmetic average roughness (Ra) is 3 μm or more or a ten-point average roughness (Rz) is 15 μm or more. apparatus.   The coil guide includes a surface portion connected to the lower end of the facing surface, and the wettability of the surface portion with respect to the paraffin wax is equal to the wettability of the facing surface with respect to the paraffin wax. The fixing device according to claim 1.   The opposed surface of the coil guide is formed such that the range in the width direction formed so as to improve the wettability to the paraffin wax includes at least the range in the width direction of the maximum recording medium that can be passed. The fixing device according to any one of claims 1 to 4, wherein the fixing device is characterized in that:   The fixing device according to any one of claims 1 to 5, wherein the facing surface of the coil guide is formed with a range in which wettability to the paraffin wax is good by sandblasting or graining.   An image forming apparatus comprising the fixing device according to claim 1.

Images