JP2014211595A - Fixing apparatus and image forming toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing apparatus which prevents change in glossiness based on toner coverage on a recording medium, in fixing an image in a non-contact manner, and to provide toner.SOLUTION: Laser beam irradiation means 10 irradiates image forming toner formed by mixing toner particles each containing a plurality of binder resins with a laser beam, to fix a toner image T formed with the image forming toner on a recording medium 100 in a non-contact manner. The binder resins contained in the image forming toner are formed by combining resins phase-separated after laser beam irradiation. A surface irregularity state of the fixed toner image T is maintained substantially constant regardless of changes in coverage of the image forming toner.

Description

  The present invention relates to a fixing device and an image forming toner.

In order to adjust the glossiness after fixing in an electrophotographic image forming apparatus, Japanese Patent Application Laid-Open Publication No. 2004-228561 discloses an image forming apparatus for forming a toner image by an electrophotographic system on a formed image in the same color system. An image forming apparatus including a developing unit having a plurality of toners having different glossinesses is disclosed.
Further, in Patent Document 2 below, in an electrophotographic image forming apparatus having a plurality of developing devices, a developing device charged with at least the same polarity and filled with a developer having the same color, or at least the same polarity. Disclosed is an image forming apparatus comprising a plurality of replaceable developing devices charged with a developer having the same color and at least one of process cartridges including the replaceable developing devices. Yes.

  In Patent Document 3 below, an image carrier that carries an electrostatic image, developing means capable of developing the electrostatic image with a plurality of toners having the same hue and different densities, and a toner image formed on a recording medium In the image forming apparatus having the toner image forming means for fixing and the fixing means for fixing the toner image to the recording medium, the usage ratio of the plurality of toners having the same hue and different densities constituting the toner image is An image forming apparatus that changes based on the glossiness of a recording medium is disclosed.

JP-A-4-204669 JP-A-8-152758 JP 2005-62843 A

  An object of the present invention is to provide a fixing device and a toner capable of suppressing a change in glossiness based on a coverage of toner on a recording medium when fixing an image by a non-contact method.

In order to achieve the above object, a fixing device according to a first aspect of the present invention includes a first toner containing a first binder resin having a glass transition temperature of Tg ₁ and a glass made from the first binder resin. An image is formed by a toner for image formation having a second toner containing a second binder resin having a high transition temperature and having no compatibility with the first binder resin at least at a temperature of Tg ₁ or higher. Receiving means for receiving the recorded recording medium, and fixing means for fixing the image forming toner to the recording medium by applying heat to the recording medium received by the receiving means in a non-contact manner. To do.

According to a second aspect of the present invention, there is provided an image forming toner comprising: a first toner containing a first binder resin having a glass transition temperature of Tg _1; and a glass transition temperature from the first binder resin. and having a second toner comprised of at least Tg ₁ or more compatibility is not at a temperature second binder resin is a high and the first binder resin.

According to a third aspect of the present invention, in the second aspect of the present invention, when the image forming toner has a coverage of a toner layer formed on a recording medium of ² to 14 g / cm ^2. Further, the glossiness after fixing is in the range of −20 to 20 of the glossiness of the recording medium.

  According to a fourth aspect of the present invention, in the second or third aspect of the invention, the first binder resin is a polyester resin, and the second binder resin is a polystyrene resin. It is characterized by being.

  According to the first aspect of the present invention, it is possible to provide a non-contact type fixing device capable of suppressing the fluctuation of the glossiness based on the coverage of the toner on the recording medium, as compared with the case without this configuration.

  According to the second aspect of the present invention, even when the image is fixed in a non-contact manner, an image that can suppress fluctuations in glossiness based on the coverage of the toner on the recording medium, compared to the case without this configuration. A toner for forming can be provided.

According to the third aspect of the present invention, there is provided an image forming toner that suppresses fluctuations in glossiness when the coverage of the toner on the recording medium is in the range of ² to 14 g / cm ² as compared with the case without this configuration. Can be provided.

  According to the invention of claim 4, the image forming toner containing the toner containing the polyester resin and the toner containing the polystyrene resin can suppress the variation in the glossiness based on the coverage of the toner on the recording medium. A toner for forming can be provided.

1 is a diagram illustrating a configuration example of a fixing device according to an embodiment. It is a figure which shows the measurement result of the glossiness after the laser fixing in an Example. FIG. 4 is a diagram illustrating an image on the surface of a toner layer after laser-fixing the mixed toner B in an example.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  FIG. 1 shows a configuration example of a fixing device according to the embodiment. In FIG. 1, the fixing device is configured as a fixing unit including a laser beam irradiation unit 10 and a recording medium conveyance device 12.

  The laser beam irradiation means 10 includes a laser light source that is arranged in an array and irradiates each laser beam, and heats the toner image T formed on the recording medium 100 by irradiating the laser beam with a transfer device (not shown). Then, the toner image T is fixed on the recording medium 100 by a non-contact method.

  The recording medium transporting device 12 includes a driving roll 12a and a follower roll 12b, and an endless belt 12c that is rotatably wound around the driving roll 12a and the driven roll 12b. The recording medium 100 transferred and formed is received from a transfer device or a paper feed mechanism that conveys the transfer medium from the transfer device to the endless belt 12c, and the recording medium 100 is conveyed in the direction of arrow A by the rotation of the endless belt 12c. The endless belt 12c is made of a heat resistant resin such as polyimide. The recording medium transport device 12 is not limited to the above configuration as long as the recording medium 100 can be transported.

  When the laser light is irradiated onto the toner image T from the laser light irradiation means 10 while the recording medium 100 is being transported by the recording medium transporting device 12, the toner for image formation constituting the toner image T is formed by the irradiation energy of the laser light. Heat is applied in a non-contact manner to melt, and the toner image T is fixed on the recording medium 100.

  The means for applying heat to the toner image T is not limited to the laser light irradiation means 10. For example, the toner image T may be heated by a heating furnace such as an electric oven or a light irradiation means such as a flash lamp.

The image forming toner according to the present exemplary embodiment includes a plurality of binder resins. The plurality of binder resins is a combination in which the binder resins are not compatible with each other at the temperature at the time of irradiation with the laser beam, that is, the temperature at the time of fixing. Here, the incompatibility at the temperature at the time of fixing means that the two resins are compatible with each other at a temperature not lower than the glass transition temperature Tg ₁ of the resin having the lower glass transition temperature (Tg) of the two binder resins. This means that they are kept separated. It is most preferable that the phase separation always takes place between Tg ₁ and the highest temperature reached at the time of fixing. For example, the phase separation occurs while cooling at the highest temperature reached at the time of fixing even though they are compatible. But you can. As a result, the plurality of binder resins are maintained in a phase-separated state even after being cooled to a temperature lower than the temperature at the time of fixing.

Further, the toner containing a plurality of binder resins means a toner obtained by mixing a plurality of types of toner particles each composed of the incompatible resin. Specifically, the first toner particles containing the first binder resin having a glass transition temperature of Tg ₁ and a glass transition temperature higher than that of the first binder resin (Tg ₂ ) and the first binder resin. The adhesion resin is a toner obtained by mixing second toner particles containing a second binder resin that is not compatible at least at a temperature of Tg ₁ or higher. The toner particles may contain a plurality of resins that are not phase-separated.

  Examples of the plurality of binder resins include polyester resins and polystyrene resins. The binder resin is not limited to a combination of a polyester resin and a polystyrene resin, and may be any resin that is not compatible at the fixing temperature. In this case, the solubility between the resins can be determined by the solubility parameter (Solubility Parameter SP value).

  Examples of the polystyrene resin include styrene-acrylic resin. Examples of the acrylic acid ester used for the styrene-acrylic resin include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and the like. The glass transition temperature (Tg) of the styrene-acrylic resin is preferably in the range of 40 to 80 ° C. When Tg is lower than 40 ° C., toner storage stability and fixed image storage stability may be deteriorated. If it is higher than 80 ° C., it may not be fixed at a lower temperature than in the past.

  The polyester resin is synthesized from, for example, a polyvalent carboxylic acid component and a polyhydric alcohol component.

  Examples of the polyvalent carboxylic acid component include oxalic acid, succinic acid, glutaric acid, adipic acid, peric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12 -Aliphatic dicarboxylic acids such as dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid; phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconic acid Aromatic dicarboxylic acids such as dibasic acids and the like, and the anhydrides and lower alkyl esters thereof are also included, but not limited thereto.

  Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and the like, and anhydrides thereof. And the lower alkyl esters. These may be used individually by 1 type and may use 2 or more types together.

  Moreover, as a polyvalent carboxylic acid component, the dicarboxylic acid component which has a sulfonic acid group other than the said aliphatic dicarboxylic acid and aromatic dicarboxylic acid may be contained.

  Furthermore, as a polyvalent carboxylic acid component, you may contain the dicarboxylic acid component which has a double bond other than the said aliphatic dicarboxylic acid and aromatic dicarboxylic acid.

  The polyhydric alcohol component is preferably an aliphatic diol, more preferably a linear aliphatic diol having a main chain portion having 7 to 20 carbon atoms. When the aliphatic diol is branched, the crystallinity of the polyester resin is lowered and the melting temperature may be lowered. Further, when the main chain portion has less than 7 carbon atoms, when polycondensation with an aromatic dicarboxylic acid, the melting temperature becomes high and fixing at low temperature may be difficult, while the main chain portion has 20 carbon atoms. Exceeding the above range makes it difficult to obtain practical materials. The number of carbon atoms in the main chain portion is more preferably 14 or less.

  Specific examples of the aliphatic diol suitably used for the synthesis of the polyester resin include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6- Hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tride Examples include, but are not limited to, candiol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosandecanediol, and the like. Among these, considering availability, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are desirable.

  Trivalent or higher alcohols can also be used as the polyhydric alcohol component, and examples thereof include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. These may be used individually by 1 type and may use 2 or more types together.

  In the binder resin, the ratio of the polyester resin to the total amount of the polyester resin and the polystyrene resin is preferably in the range of 75 to 90% by mass in the toner obtained by mixing the plurality of types of toner particles. is there.

The toner for image formation of the present embodiment described above has a glossiness after fixing by the non-contact method when the coverage of the toner layer formed on the recording medium 100 is ² to 14 g / cm ^2. (Gloss) is preferably in the range of -20 to 20 glossiness of the recording medium 100.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to these Examples.

<Preparation of mixed toner>
EAECO toner (binder resin: polyester resin, SP value 10.1) manufactured by Fuji Xerox Co., Ltd. and EAHG toner (binder resin: polystyrene resin, SP value 9.0) were prepared, and these were prepared as EAECO toner: EAHG toner = 87.5: 12.5, 75:25, and 50:50 were mixed at a mass ratio to prepare a mixed toner. Hereinafter, the toner with EAECO toner: EAHG toner = 87.5: 12.5 is referred to as mixed toner A, the toner with 75:25 is referred to as mixed toner B, and the toner with 50:50 is referred to as mixed toner C.

<Fixing to recording media>
A toner image was fixed on a recording medium using the above mixed toners under the following conditions. Among these, the case where the mixed toner A is used is Example 1, and the case where the mixed toner B is used is Example 2. On the other hand, the case where the mixed toner C is used is Comparative Example 1.

  Further, in the same manner, the EAECO toner alone, the EAHG toner alone, and the low-viscosity toner (a toner using a low molecular weight resin having an SP value of 10.1) using a binder resin having a lower viscosity than these. The images were fixed on a recording medium, and Comparative Examples 2, 3, and 4 were used, respectively.

Fixing conditions: An image forming apparatus (trade name: Docu Center Color 2220, manufactured by Fuji Xerox Co., Ltd.) was used, and a light source for the light fixing apparatus, COHERENT, trade name: HighLight ISL-2000L (exposure wavelength: 808 nm) was attached. The irradiation energy was set to 2.5 J / cm ² , and a fixed image was obtained using each of the mixed toners and the individual toners. In this case, laser fixing was performed while changing the coverage (unit: g / cm ² ) of the toner layer (toner image) formed on the recording medium by the image forming apparatus. When the coverage is increased, unevenness is reduced from the surface of the toner layer, and the toner layer tends to become smooth, so that the glossiness generally tends to increase. Therefore, if the glossiness when the coverage is high can be suppressed, the fluctuation of the glossiness based on the coverage can be suppressed.

  The glossiness of the recording medium used was 40 at 60 ° gloss measured by the measurement method shown below.

<Glossiness measurement method>
The glossiness at a light incident angle of 60 degrees with respect to the fixed image thus fixed was determined using Gloss Meter GM-26D (Murakami Color Research Laboratory).

FIG. 2 shows the measurement result of the glossiness after laser fixing. In FIG. 2, the horizontal axis represents the coverage TMA of the toner layer formed on the recording medium, and the vertical axis represents the glossiness (60 ° gloss). 2, in Examples 1 and 2 using the mixed toners A and B, the glossiness after fixing when the coverage of the toner layer formed on the recording medium is ² to 14 g / cm ^2. Is in the range of -20 to 20 (20 to 60) of the glossiness (40) of the recording medium. This is because the polyester resin of EAECO toner and the polystyrene resin of EAHG toner melt at the time of laser light irradiation, but there is a difference in SP value between the two resins and the compatibility is low. Because. When the two resins are phase-separated, the unevenness on the surface of the toner layer after fixing is maintained, and even if the coverage TMA changes, the change in the unevenness on the surface of the toner layer is suppressed. As a result, it is possible to prevent the glossiness from rising excessively even if the coverage ratio TMA increases.

  On the other hand, in Comparative Example 1 using the mixed toner C, the glossiness does not increase even when the laser beam is irradiated, and when the coverage TMA is 8 or less, the gloss is lower than the lower limit (20) of the above range (20-60). It is a degree. This is because the ratio of the polystyrene resin that is difficult to melt out of the resin contained in the mixed toner C is as high as 50% by mass, so that the unevenness of the surface of the toner layer after fixing becomes large and the glossiness is sufficiently increased. It is because it is not possible.

Further, in Comparative Example 2 in which EAECO toner was used alone, the glossiness greatly increased as the coverage TMA increased, and the upper limit (60) of the above range (20-60) when the coverage TMA was 6 g / cm ² or more. Is over. This is because, since only a polyester resin that is easily melted is used, the unevenness on the surface of the toner layer after fixing is reduced particularly in a range where the coverage is high, and the surface becomes easy to be smooth and the glossiness is increased.

  Further, in Comparative Example 3 in which the EAHG toner is used alone, the glossiness does not increase even when the laser beam is irradiated, and when the coverage TMA is 10 or less, it is lower than the lower limit (20) of the above range (20 to 60). It is glossy. This is because only the polystyrene-based resin that is difficult to melt is used, and as in Comparative Example 1, the surface of the toner layer after fixing becomes large and the glossiness cannot be sufficiently increased. .

Further, in Comparative Example 4 in which the low-viscosity toner was used alone, the glossiness increased greatly as the coverage TMA increased, and the upper limit (60-60) of the above range (20-60) when the coverage TMA was 7 g / cm ² or more. ) Is exceeded. Since only a low viscosity that is easy to melt is used, as in Comparative Example 2, unevenness on the surface of the toner layer after fixing is easily reduced and smoothened in a high coverage range, and the glossiness is high. Because it becomes.

  3A and 3B show images on the surface of the toner layer after the mixed toner B is laser-fixed (after laser light irradiation). 3A is a photograph taken with an optical microscope, and FIG. 3B is a height profile taken with a laser microscope. As shown in FIG. 3A, it can be seen that the mixed resin is phase-separated after the laser beam irradiation. In FIG. 3 (a), what looks like particles is a polystyrene resin. Further, as shown in FIG. 3B, irregularities can be confirmed on the surface of the toner layer in the period of the polystyrene-based resin that looks like particles in FIG. The unevenness suppresses an excessive increase in glossiness in a range where the coverage TMA is high.

  DESCRIPTION OF SYMBOLS 10 Laser beam irradiation means, 12 Recording medium conveying apparatus, 12a Drive roll, 12b Judo roll, 12c Endless belt, 100 Recording medium.

Claims (4)

A first toner containing a first binder resin having a glass transition temperature of Tg ₁ and a glass transition temperature higher than that of the first binder resin, and the first binder resin being at least Tg ₁ or higher. Receiving means for receiving a recording medium on which an image is formed with an image forming toner, the second toner containing a second binder resin that is not compatible at temperature; and
And a fixing unit that heats the recording medium received by the receiving unit in a non-contact manner and fixes the toner for image formation onto the recording medium. A first toner comprising a first binder resin having a glass transition temperature of Tg ₁ ;
A second toner containing a compatibility no second binder resin in the first and higher glass transition temperature than the binder resin of the first binder resin is at least Tg ₁ or higher,
An image-forming toner comprising: The toner for image formation has a glossiness after fixing in the range of −20 to 20 of the glossiness of the recording medium when the coverage of the toner layer formed on the recording medium is ² to 14 g / cm ^2. The toner for image formation according to claim 2.   4. The image forming toner according to claim 2, wherein the first binder resin is a polyester-based resin, and the second binder resin is a polystyrene-based resin. 5.

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