JPH01134385A - Fixing method - Google Patents

Abstract

PURPOSE:To perform fixation with a short warm-up time without any offset nor any damage to a support body by heating toner consisting primarily of metal powder or magnetic powder and thermoplastic resin with an alternating magnetic field and fixing it on the support body. CONSTITUTION:Toner particles 6a and 6b consisting principally of metal powder or magnetic powder and thermoplastic resin are arranged on the support body 1 and conveyed by a belt 2. The toner particles pass through the alternating magnetic field applied by a coils 5a and 5b provided by a conveyance path and conductors in the toner particles are heated by inductive heating operation, etc., to fuse the thermoplastic resin with the heat, so that the toner particles 6a and 6b are fixed on the support body 1. At this time, the coils 5a and 5b are made preferably of superconductive members so as to increase the magnetic field.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for fixing images in electrophotography, electrostatic recording, etc., which utilizes heat generation effect due to dielectric heating effect of a conductor or the like.

[Prior Art] Image fixing methods using heat can be broadly classified into contact type and non-contact type, depending on the positional relationship between the heat source and the object to be fixed.

The main non-contact methods include methods using (a) ultraviolet lamps, (b) ovens, (C) flash, and (d) microwaves (dielectric heating). On the other hand, examples of the contact type include methods using heat rolls and hot plates.

[Problems to be Solved by the Invention] However, the contact type has drawbacks such as easy wrinkles and curls, short parts life, long warm-up time, and strict conditions for offset.

Among the non-contact methods, the flash method (C), which is mainly used, has drawbacks such as low thermal efficiency of about 30 to 40%, high parts cost, and large space. ,
The method (d) has drawbacks such as low efficiency of 50% or less, high equipment cost, and difficulty in setting conditions.

An object of the present invention is to provide an image fixing method that solves the above problems.

[Means for Solving the Problem] The above object is to arrange a toner mainly composed of metal powder or magnetic powder and a thermoplastic resin on a support, apply an alternating magnetic field to the toner, and This can be achieved by a fixing method characterized in that the metal powder is heated by induction heating effect and/or hysteresis loss by an alternating magnetic field, thereby melting the thermoplastic resin in the toner and fixing it on the support.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic side view showing an embodiment of the present invention.

In this embodiment, a belt 2 for conveying the support l;
Roller 3.4 for supporting and driving the belt 2
A device is used whose main parts include coils 5a and 5b for applying an alternating magnetic field.

With this device, images are fixed in the following manner. That is, a toner 6a containing a conductor arranged at a desired part on the support 1 according to information by ordinary electrophotography, electrostatic recording, etc. is conveyed by the belt 2, and is conveyed by a coil provided in the conveyance path. The image is fixed by passing through the alternating magnetic field applied by 5a and 5b (
This fixed image is created by toner 6b).

The principle of fixing achieved in this manner is that conductors in the toner are heated by dielectric heating or the like due to an alternating magnetic field, and the thermoplastic resin of the toner is melted by this heat.

FIGS. 2A and 2B are schematic diagrams showing typical forms of toner used in the image fixing method of the present invention. (A) shows a form in which metal powder 21 is coated with a composition 22 mainly composed of a thermoplastic resin, and (B) shows a form in which metal particles 23 are dispersed in a composition 22 mainly composed of a thermoplastic resin. It is a matter of form.

The thermoplastic resin in composition 22 is preferably styrene, polyester, acrylic, etc., but is not particularly limited.

In addition to such thermoplastic resins, the composition 22 may include components for imparting desired image characteristics and electrostatic characteristics, such as colorants and charge suppressants.

Metal powder 21 in toner as shown in (A) and (B)
The metal grains 22 may be magnetic or non-magnetic, and may be made of, for example, a single substance such as AI Fe or Cu, or an alloy consisting of a combination thereof.

Note that the particle size of the toner is preferably about 5 to 30 μm.

In the present invention, fixing uses dielectric heating as described above, but if the conductor in the toner is a magnetic material, the heat generation effect due to hysteresis loss is also used for image fixing.
It is desired to improve fixing efficiency by ~3 times.

The power absorbed by the eddy current product of a conductor due to electromagnetic induction, etc. is
It is expressed as Q=kH2fT lower lower τj. Here, H: Magnetic field strength constant f: Alternating frequency ρ: Resistivity μ of the conductor: Non-permeability of the conductor: A constant.

As is clear from this equation, it is optimal to increase the magnetic field strength H in order to inductively heat the minute conductor contained in the toner to the temperature required for fixing.

In order to achieve an increase in magnetic field strength, it is preferable that the coil of the alternating magnetic field generating means be made of a superconducting material.The material may be an alloy or metal such as NbTi or NbSSn. , A-B-C-D (however,
A is La, Ce, Pr, Nd, Pm.

Sm, Eu, Gd, Tb, Dy, Ho, Er.

A group consisting of Tm, Yb, Lu, Y and Sc, B is Ca,
A group consisting of Sr, Pb and Ba, C is V.

Ti, Cr, Mn, Fe, Ni, Co, Ag.

D is one or more elements selected from the group consisting of Cd, Cu, Zr, and Hg, and D is selected from the group consisting of S, 0, and F, respectively. ) can also be used. However, there are no particular limitations on the materials.

In the present invention, the alternating frequency of the applied magnetic field can be set to an optimal condition that matches the toner layer thickness by considering the following equation.

d: Penetration thickness of eddy current due to electromagnetic induction α: Constant f:
Frequency In the present invention, the coils are not only disposed on both sides of the support as in the above embodiments, but may also be disposed only on the -blade side (both methods are referred to as horizontal axis magnetic flux methods). .

Furthermore, a method called a vertical axis magnetic flux method, in which magnetic flux is distributed in a direction parallel to the surface of the support body, can also be used.

[Effects of the Invention] As explained in detail above, the fixing method of the present invention is: ・Since it is a non-contact method, there is no concern about offset, and there is no damage to the support. ・For the same reasons as above, Also, since there are no moving parts, the life of the parts is long. ・Warm-up time is short. ・Since only the necessary parts can be heated, there is no temperature rise in attached equipment, etc., and there is no need to consider this.・By using superconductors, it can be constructed in less space.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing one embodiment of the present invention, and FIGS. 2(A) and (B) are schematic diagrams showing typical forms of toner used in the image fixing method of the present invention. It is. l: Support 2: Belt 3.4 = Roller 5a, 5b: Coil 6a, 6b;
toner

Claims (1)

[Claims] 1) A toner mainly composed of metal powder or magnetic powder and a thermoplastic resin is placed on a support, an alternating magnetic field is applied to the toner, and the metal powder in the toner is removed by the alternating magnetic field. A fixing method characterized by generating heat by induction heating action and/or hysteresis loss, thereby melting a thermoplastic resin in the toner and fixing it on a support. 2) The fixing method according to claim 1, wherein the alternating magnetic field is generated by a coil made of a superconducting member.