JP2000221814A - Method for fixation and manufacture of toner for infrared ray fixation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make fixing efficiency improved by raising infrared ray receiving efficiency of toner, in the method for fixation of the infrared ray fixing system. SOLUTION: In the method for fixation by projecting the infrared ray to the unfixed toner on recording material and heat/fixing the above toner on the recording materiel, the infrared ray receiving area for unit area of the unfixed toner 5 is increased on recording materiel 4, in such a manner, the infrared ray absorption efficiency of the toner is improved, therefore fixing property can be improved. Moreover, as the method for increasing the infrared ray receiving area for the unit volume of the unfixed toner 5 on the recording material 4, the toner in a flat shape is adopted as the toner therefor, or the method such as respectively breaking the toner into the finer particle on an intermediate transfer body or the like prior to transferring on the recording material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing method applied to an electrophotographic recording type image forming apparatus such as a copying machine, a facsimile, a printer, etc., and more particularly to a method of irradiating unfixed toner on a recording material with infrared rays. The present invention relates to a fixing method for heating and fixing the toner to a recording material, and a method for producing an infrared fixing toner used in the fixing method.

[0002]

2. Description of the Related Art In an image forming apparatus of an electrophotographic recording system such as a copying machine, a facsimile, a printer, etc., an electrostatic latent image is formed on an image carrier such as a photoconductor by optical writing or the like according to image information. After forming the toner image by developing the latent image with toner of a developing device, the toner image is transferred to a recording material such as recording paper and fixed to obtain a fixed image. As a fixing method applied to an apparatus, a fixing method of irradiating unfixed toner on a recording material with infrared rays to heat and fix the toner to the recording material is known. As an improved technique of this fixing method, Japanese Patent Application Laid-Open No. 63-231361 discloses a fixing method of a toner by irradiating infrared rays by limiting the peak wavelength range of the irradiating infrared rays to a range of 5 μ ± 1 μm. There is disclosed a technique for improving the absorption efficiency of the toner and speeding up the fixing operation, appropriately heating the base such as recording paper to improve the fusion of the toner, and preventing the heat loss. Japanese Patent Application Laid-Open No. 9-179347 discloses a color toner for improving the fixability by a flash fixing method using near-infrared rays, which includes at least a near-infrared ray comprising a chromatic pigment, carbon black, and a binder resin. In the color toner for developing an electrostatic image for flash fixing, the amount of carbon black used is 5 to 40 parts by weight when the total amount of carbon black and chromatic pigment is 100 parts by weight. Is disclosed.

[0003]

The above prior art attempts to improve the fixing efficiency by defining the characteristics of the infrared radiation device and the color toner for infrared fixing. However, in these methods, there is a problem in that the material and structure of the heater or the material and manufacturing method of the toner need to be special in order to match the emission wavelength, so that the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a fixing method having means for improving infrared fixing efficiency even when a general toner is used. It is another object of the present invention to provide a method for producing an infrared fixing toner used in the fixing method.

Further, the object of each claim of the present invention is specifically described. The object of claim 1 is to increase the infrared ray receiving efficiency of the toner and improve the fixing efficiency. An object of claim 2 is to provide conditions for effectively achieving the object of claim 1. A third object of the present invention is to provide a simple method for producing a toner used to achieve the object of the second embodiment. The object of Claim 4 is to claim 1
And a method for effectively realizing the object of the present invention. An object of claim 5 is to provide a specific method for realizing the object of claim 4. An object of claim 6 is to provide a more specific method for effectively performing the method of claim 4 or 5.

[0006]

According to a first aspect of the present invention, a latent image is formed on an image carrier in accordance with image information, and the latent image is developed with toner. A fixing method applied to an image forming apparatus in which after forming a toner image, transferring the toner image to a recording material and fixing the image to obtain an image, irradiating unfixed toner on the recording material with infrared rays. In a fixing method of heating and fixing the toner on a recording material, an infrared receiving area per unit volume of the unfixed toner on the recording material is increased.

According to a second aspect of the present invention, in the fixing method of the first aspect, the infrared receiving area of the toner per unit volume of the unfixed toner on the recording material is increased by setting the infrared receiving area of the toner to S, When the volume of the toner is V, a toner satisfying the following expression (1) is used.

[0008]

(Equation 2)

According to a third aspect of the present invention, there is provided a method for producing an infrared fixing toner used in the fixing method according to the second aspect, wherein the method for producing a toner having a large infrared receiving area is as follows.
It is characterized in that a toner produced by a pulverization method, a polymerization method, or another method is heated and pressed by a hot-press roller provided with a fixed gap to have a flat shape.

According to a fourth aspect of the present invention, there is provided the fixing method according to the first aspect, wherein the infrared light receiving area per unit volume of the unfixed toner on the recording material is increased on the image carrier. Before or after transferring the toner image to the recording material, the toner forming the toner image is broken into finer particles, and then the toner is irradiated with infrared rays to heat and fix the toner to the recording material. Is what you do.

According to a fifth aspect of the present invention, in the fixing method of the fourth aspect, a method of applying pressure is used as a method of crushing the toner.

The invention according to claim 6 is the invention according to claim 4 or 5.
In the fixing method described above, the toner image formed on the image carrier is transferred to an intermediate transfer member, and the toner that forms the unfixed toner image by pressing on the intermediate transfer member is crushed into finer particles. Transferring the toner to a recording material, irradiating the toner on the recording material with infrared rays, and heating and fixing the toner to the recording material.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating an example of an infrared fixing device. The infrared fixing device 1 includes an infrared heater 3 and a reflecting mirror 2, and reflects infrared light emitted from the infrared heater 3 by the reflecting mirror 2 to irradiate unfixed toner 5 on a recording material 4 such as paper. The toner 5 is heated and melted and fixed on the recording material 4. Examples of the infrared heater 3 include a halogen lamp, a ceramic heater, a quartz heater, and an infrared flash. The shape of the reflecting surface of the reflecting mirror 2 may be a parabolic surface or an elliptical surface depending on the purpose, and the reflecting surface must be coated with a material that efficiently reflects infrared rays. There is also.

In the case of infrared fixing using the fixing device having the structure shown in FIG. 1, the energy of infrared rays applied to the toner is changed to heat and the toner is heated and fixed. Therefore, in order to fix the toner efficiently, it is necessary to receive more infrared rays to the volume of the toner. For this purpose, the area of the toner to be irradiated with infrared rays may be increased with respect to the volume of the toner. That is, the infrared receiving area per unit volume of the unfixed toner 5 on the recording material 4 is increased (claim 1). Here, the area receiving infrared radiation (infrared light receiving area) refers to the area of a region that receives infrared light (light) directly when irradiated with infrared light (light). For example, in the case of the spherical toner 6 as shown in FIG. 2, when light (infrared rays) is applied from above, the area S of the portion directly exposed to light
In the case of a sphere, it is the upper half area (white portion). If the surface area of the sphere is S _S , S = S _S /
2.

The toner generally used at present is manufactured by a pulverization method, and FIG. 3 schematically shows the shape of the toner. Although the toner 7 produced by the pulverization method is actually considerably uneven and has a certain degree of variation in the particle size, it is schematically shown in this figure as a spherical shape. In order to increase the infrared receiving area per unit volume of the toner as in the first aspect of the present invention, a flat toner that can improve the infrared receiving efficiency compared to the spherical toner is preferable. FIG. 4 shows an example of a flat toner. In the example of FIG. 4, an example of the flat toner 5 a having a circular infrared receiving surface and the flat toner 5 b having a quadrangular shape is described. However, the shape of the infrared receiving surface is not limited to these, and the infrared receiving surface per unit volume is not limited thereto. Any shape may be used as long as the infrared receiving area can be large.

Here, conditions for making the infrared receiving area of the flat toner having the same volume as the toner having a nearly spherical shape larger than the infrared receiving area of the spherical toner will be described below. The volume V _S and the surface area S _S of the spherical toner can be represented by ^{_{V S = 4πr 3/3 S}} S = 4πr 2. On the other hand, when the infrared receiving area of the flat toner is S and the thickness is d, the volume V can be expressed by the following equation. V = Sd

When the spherical toner and the flat toner have the same volume (V _S = V), the toner having a flat shape is larger than the light receiving area (= S _S / 2 = 2πr ² ) of the spherical toner. for the light receiving area S increases _{(S> (S S / 2} )) where in, from V _S = V, a 4πr ^3/3 = Sd, r is expressed by the following equation.

[0018]

(Equation 3)

In this case, since S> (S _S / 2) = 2πr ² and V = Sd, the relationship between the infrared light receiving area S and the volume V of the flat toner and the light receiving area The relationship between S and thickness d is expressed as follows.

[0020]

(Equation 4)

Therefore, by using a toner having a shape in which the infrared ray receiving area S and the volume V satisfy the above equation (1), the infrared ray receiving efficiency can be made higher than that of the spherical toner, and the fixing performance can be improved. Can be improved (claim 2).

The preparation of a flat toner as shown in FIG. 4 is performed as follows. That is, grinding method, polymerization method,
After a normal toner is produced by another method, the toner is crushed by applying heat and pressure between heat-pressing rollers (heat rollers) provided with a certain gap appropriately determined from the average particle size of the toner, thereby flattening the toner. (Claim 3). At this time, the temperature of the heat roller may be about the softening point of the toner because the toner may be soft. However, it is preferable to provide a pre-heating device so that the whole toner is heated to a soft temperature before being pressed by the roller. Further, the surface of the heat roller is preferably made of a material that does not easily adhere, such as Teflon, or is subjected to an anti-adhesion treatment such as applying silicone oil or the like to the roller surface so that the toner does not adhere.

Next, another method for increasing the infrared receiving area per unit volume of the unfixed toner on the recording material will be described. In the electrophotographic recording method, an electrostatic latent image is formed on an image carrier such as a photoreceptor in accordance with image information, developed with a conventional toner having a shape close to a sphere, and then recorded on a recording paper or the like. After the toner image formed on the image carrier is transferred to the recording material before or after the transfer, the toner for forming the toner image is crushed into finer particles to develop an infrared light receiving area. Can be increased (claim 4). That is, as shown in FIG. 5, by crushing the toner particles 7 into finer particles of toner 7 ', the ratio of the infrared receiving area to the volume of the toner is increased, and the infrared receiving efficiency is improved. At this time, since the toner around room temperature is hard, it can be broken by applying an impact or pressure.

As an example of a method of crushing the toner, there is a method of crushing the toner by applying a pressure to the toner with a pair of pressure rollers 8a and 8b as shown in FIG. Also, after directly applying pressure to an image formed on an image carrier such as a photoreceptor with a pressure roller or transferring the image to a recording material such as recording paper, recording is performed by pressing with a pair of pressure rollers before fixing. The toner may be crushed on the material. However, if pressure is applied on the photoconductor, the photoconductor may be damaged, and if pressure is applied on the recording material, the recording material may be crushed.

Therefore, as shown in FIG. 7, the toner image developed on the photosensitive member 9 is once transferred from the photosensitive member 9 to the intermediate transfer member 10, and then the toner image is paired on the intermediate transfer member 10. Is pressed by the pressure rollers 8a and 8b to break the toner into finer particles, and then the image of the crushed toner is transferred to the recording material 4, and the unfixed toner on the recording material 4 is irradiated with infrared rays by the infrared fixing device 1. To irradiate the toner with the recording material 4
It is better to fix by heating (claim 6).

[0026]

EXAMPLES Hereinafter, more specific examples of the present invention and comparative examples will be described.

(Example 1: Examples of the invention according to claims 1, 2 and 3) A polystyrene-acrylic copolymer having a glass transition point of 70 ° C. kneaded with carbon black as a coloring material is finely ground by a pulverizing method. Then, a toner having a particle size of 6 μm is taken out by a classifier. Then, after preheating through a heating furnace at 90 ° C., a surface temperature 9 having a gap of 2 μm is provided.
A flat toner was produced by passing between 0 ° C. heat roller pairs. The flat toner is filled in a developing device of a plain paper copier Spirio7000 (trade name, manufactured by Ricoh) without the fixing device, and a latent image is formed and developed to produce a sample of an unfixed toner image on the photoconductor. After that, the image was transferred to recording paper. The sample of the unfixed toner image transferred to the recording paper was heated by the infrared fixing device 1 shown in FIG. The infrared heater 3 of the fixing device 1 is a halogen lamp (peak wavelength: about 1 μm), and the reflecting mirror 2 has an elliptical reflecting surface. As a result, good fixing could be performed.

Example 2 Example of the Invention According to Claims 1, 4, 5, and 6 Polystyrene having a glass transition point of 70 ° C.
Acrylic copolymer kneaded with carbon black as a coloring material is finely ground by a pulverization method and has a particle size of 6 μm by a classifier.
Remove the toner. The toner is charged into a developing device of a plain paper copying machine Spirio7000 (trade name, manufactured by Ricoh) from which the fixing device has been removed, and after forming a latent image and developing, a sample of an unfixed toner image is formed on a photoreceptor. Thickness 100μ
A sample of the unfixed toner image was transferred onto a stainless steel plate having a length of m. Then, the stainless plate on which the unfixed toner image has been transferred is passed between a pair of pressure rollers made of metal, and the unfixed toner image is pressed by the pair of pressure rollers to crush the toner into finer particles. Then, the toner image was transferred to recording paper and fixed by the infrared fixing device 1 shown in FIG. The infrared heater 3 of the fixing device 1 is a halogen lamp (peak wavelength: about 1 μm), and the reflecting mirror 2 has an elliptical reflecting surface. As a result, good fixing could be performed.

Comparative Example A polystyrene-acrylic copolymer having a glass transition point of 70.degree. C., which is the same material as in Examples 1 and 2, kneaded with carbon black as a coloring material is finely classified by a pulverization method and classified. The toner having a particle size of 6 μm is taken out by the apparatus. The toner is charged into a developing device of a plain paper copying machine Spirio7000 (trade name, manufactured by Ricoh) from which the fixing device has been removed, and after forming a latent image and developing, a sample of an unfixed toner image is formed on a photoreceptor. The unfixed toner image was transferred onto the recording paper. Thereafter, similarly to the first and second embodiments, the image was fixed by the infrared fixing device 1 shown in FIG.
Fixing was insufficient.

As is clear from the results of Examples 1 and 2 and the comparative example, the flat toner is used, or the unfixed toner is crushed to have a fine particle size, so that the toner on the recording paper can be used. Since the infrared receiving area per unit volume of the unfixed toner can be increased and the infrared absorption efficiency can be improved, the fixing performance can be improved.

[0031]

As described above, according to the first aspect of the present invention, in a fixing method in which an unfixed toner on a recording material is irradiated with infrared rays to heat and fix the toner on the recording material, By increasing the infrared receiving area per unit volume of the unfixed toner, the infrared absorption efficiency is improved, and the fixing performance can be improved.

According to a second aspect of the present invention, in the fixing method according to the first aspect, the infrared receiving area per unit volume of the unfixed toner on the recording material is increased by setting the infrared receiving area of the toner to S, When the volume of the toner is V, by using a toner satisfying the following expression (1), the infrared absorption efficiency is improved, and the fixing performance can be improved.

[0033]

(Equation 5)

According to a third aspect of the present invention, there is provided a method for producing an infrared fixing toner used in the fixing method according to the second aspect, wherein the toner having a large infrared receiving area is produced.
The toner produced by the pulverization method, polymerization method, or other method is heated and pressed by a hot-press roller provided with a certain gap to make the toner into a flat shape, thereby easily producing a toner having a large infrared receiving area. be able to.

According to a fourth aspect of the present invention, in the fixing method according to the first aspect, a method of increasing the infrared receiving area per unit volume of the unfixed toner on the recording material by forming the unfixed toner on the image carrier is used. Before or after transferring the toner image to the recording material, the toner forming the toner image is crushed into finer particles, and then the toner is irradiated with infrared rays to heat and fix the toner to the recording material. By using this method, the infrared receiving area can be increased to improve the infrared absorption efficiency, and the fixing performance can be improved.

According to the fifth aspect of the present invention, in the fixing method according to the fourth aspect, a method of applying pressure is used as a method of crushing the toner. Thus, the fixing performance can be improved.

According to a sixth aspect of the present invention, in the fixing method according to the fourth or fifth aspect, the toner image formed on the image carrier is transferred to an intermediate transfer member, and the toner image is pressed on the intermediate transfer member. After crushing the toner forming the unfixed toner image into finer particles, the toner is transferred to a recording material,
Since the toner on the recording material is irradiated with infrared rays to heat and fix the toner on the recording material, the unfixed toner can be reliably and effectively crushed on the intermediate transfer member before being transferred to the recording material, It is possible to improve the infrared absorption efficiency by increasing the infrared light receiving area and improve the fixing performance.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of an infrared fixing device.

FIG. 2 is an explanatory diagram of a light receiving area when a spherical toner is irradiated with light (infrared rays).

FIG. 3 is a diagram schematically illustrating the shape of a general toner manufactured by a pulverization method.

FIG. 4 is a diagram illustrating an example of a flat toner.

FIG. 5 is a diagram illustrating an example in which toner particles are crushed into finer toner particles.

FIG. 6 is a diagram illustrating an example of a method of crushing toner, and is an explanatory diagram of a method of crushing toner by applying pressure to the toner with a pair of pressure rollers.

FIG. 7 is an explanatory diagram of a fixing method in which unfixed toner is crushed on an intermediate transfer member, transferred to a recording material, and fixed by infrared rays.

[Explanation of symbols]

 1: Infrared fixing device 2: Reflector 3: Infrared heater 4: Recording material 5: Toner having a large infrared receiving area 5a: Flat toner having a circular infrared receiving surface 5b: Flat toner having a rectangular infrared receiving surface 6, 7 : Spherical toner 7 ': Toner pulverized into fine particles 8a, 8b: Pressure roller 9: Photoconductor (image carrier) 10: Intermediate transfer member

Claims (6)

[Claims] A latent image formed on an image carrier in accordance with image information; developing the latent image with toner to form a toner image; transferring the toner image to a recording material; A fixing method applied to an image forming apparatus for obtaining an image, wherein the fixing method comprises irradiating unfixed toner on the recording material with infrared rays and heating and fixing the toner to the recording material. A fixing method characterized by increasing an infrared receiving area per unit volume of a toner. 2. The fixing method according to claim 1, wherein the infrared receiving area per unit volume of the unfixed toner on the recording material is increased by setting the infrared receiving area of the toner to S and the volume of the toner to V. Wherein a toner satisfying the following expression (1) is used. (Equation 1) 3. A method for producing an infrared fixing toner used in the fixing method according to claim 2, wherein the toner produced by a pulverization method, a polymerization method, or another method is used as a method for producing a toner having a large infrared receiving area. A method for producing a toner for infrared fixing, characterized in that the toner is formed into a flat shape by heating and pressing with a hot pressing roller provided with a certain gap. 4. The fixing method according to claim 1, wherein the toner image formed on the image carrier is applied to the recording material by increasing the infrared receiving area per unit volume of the unfixed toner on the recording material. Before or after transfer, the toner forming the toner image is crushed into finer particles,
Thereafter, the toner is irradiated with infrared rays to heat and fix the toner to a recording material. 5. The fixing method according to claim 4, wherein a method of applying pressure is used as a method of crushing the toner. 6. The fixing method according to claim 4, wherein the toner image formed on the image carrier is transferred to an intermediate transfer member, and an unfixed toner image is formed by pressing the intermediate transfer member. Fixing the toner to a recording material, irradiating the toner on the recording material with infrared rays, and heat-fixing the toner to the recording material.