JPH08286454A - Image forming method and thermal fixing method - Google Patents

Abstract

PURPOSE: To provide an image forming method capable of forming a projected image with high transparency on a transparent sheet. CONSTITUTION: In the image forming method using the transparent sheet having at lest a sticking layer on a translucent sheet, as a toner image substrate 6, the sticking layer has a layer thickness of 2-10μm, toner has ten pieces of percent of grains whose diameters are smaller that the layer thickness of the sticking layer and as the toner, color toner is used. In a method for thermally fixing a toner image in such a manner that the toner image substrate 6 carried on the transparent sheet having the sticking layer on the translucent sheet passes through the gap between a fixing member 1 and a pressure member 5, the sticking layer has a layer thickness of 2-10μm and the toner has ten pieces of percent of the grains whose diameters are smaller than the layer thickness of the sticking layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method and a heat fixing method for forming an image having high transparency on a translucent sheet.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic method, a heat roller fixing method has been widely used because it fixes a toner image carried on a recording material and thus has high thermal efficiency and is suitable for high speed fixing. This heat roller fixing method is a method in which a recording material carrying a toner image is passed through a pressure contact position between a fixing roller having a built-in heat source and a pressure roller, and the toner image is melted and fixed on the recording material.

In recent years, an overhead projector (OH) has been used to form a color image on a transparent sheet by electrophotography.
A method of using P) as a projection image is widely used. However, with this method, only a dark projected image with low saturation was obtained due to problems such as the refraction of light between the toner image and the transparent sheet and the smoothness of the formed toner image itself. In order to solve this problem, various measures have been taken on the transparent sheet itself.

For example, Japanese Patent Application Laid-Open No. 2-263642 proposes a transparent sheet having a transparent resin, which is compatible with the toner resin and has a higher storage elastic modulus than the toner resin at the fixing temperature, on the surface thereof. Further, JP-A-5-88400 proposes a transparent sheet having a transparent resin layer having a lower apparent melt viscosity than the toner resin on the surface. However, although these methods can be expected to improve the adhesiveness between the toner and the transparent sheet, it has been difficult to improve the adhesiveness for all toners and to secure the transparency. That is, the toner has a peculiar particle size distribution, and the large particle size toner present in the toner is insufficient in melting due to heat, lacks smoothness and solubility in the adhesive layer, and has a desired transparency. Cannot be secured.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems. That is, the present invention is to provide an image forming method capable of forming a highly transparent projected image on a translucent sheet.

[0006]

The above object is an image forming method using a transparent sheet having an adhesive layer on at least a translucent sheet as a toner image support, wherein the adhesive layer is a layer having a thickness of 2 to 10 μm. This can be achieved by an image forming method characterized in that 10% by number or more of the toner having a particle diameter equal to or smaller than the thickness of the adhesive layer is present.

The above object is also achieved by an image forming method characterized in that the toner is a color toner.

Further, the above object is to provide a method of thermally fixing a toner image support carrying a toner image on a transparent sheet having an adhesive layer on a translucent sheet by passing it between a fixing member and a pressing member. And an adhesive layer having a layer thickness of 2 to 10 μm, and the toner having a particle diameter equal to or less than the layer thickness of the adhesive layer is present in an amount of 10% by number or more. It

The present invention improves the adhesion to the adhesive layer formed on the transparent sheet by controlling the particle size distribution of the toner itself, and as a result, improves the transparency of the image formed on the transparent sheet. They found that they could do so and completed the invention.

That is, in order to improve the adhesion of the toner to the adhesive layer, it is necessary to enhance the melting of the toner and improve the adhesion to the adhesive layer. For this purpose, it has been found that the adhesive layer and the toner particle size are closely related, and the adhesiveness can be improved by the presence of a specific number or more of toner particles having a particle size corresponding to the layer thickness of the adhesive layer. In order to bring the adhesive layer into close contact with the toner itself, it is necessary for the toners to have close contact with each other. First, it is possible to improve the adhesion between the adhesive layer and the toner layer by bringing the toner having a small particle diameter into close contact with the adhesive layer and further adhering the small particle toner and the other toner in a molten state. Presumed.

(Structure) Structure of Transparent Sheet The transparent sheet is not particularly limited. For example, a transparent film of polystyrene, polyethylene, polyethylene terephthalate or the like can be used. Suitable examples include biaxially oriented polyethylene terephthalate (PET base). The sheet itself has a film thickness of 10 to 300 μm, preferably 50 to 250 μm. When this film thickness is large, it becomes difficult to pass through the fixing unit, and further, heat transfer is insufficient, and the fixability cannot be secured. Further, when the film thickness is small, sufficient strength as an image support cannot be maintained.

The adhesive layer is a layer that is compatible with the toner resin and has a layer thickness of 2 to 10 μm. When the layer thickness is thin, the adhesion with the toner cannot be secured, and when the layer thickness is large, the transparency is deteriorated due to the difference in refractive index between the transparent sheet and the adhesive layer.

As the constitution of the adhesive layer itself, it is preferable to select a resin having a high solubility in the toner resin.

As the highly soluble resin, those having a softening point close to that of the toner, particularly those having a softening point within ± 15 ° C. with respect to the softening point of the toner are used. Further, it is preferably −15 to + 5 ° C. with respect to the toner softening point. Further, it is preferable that the compositions have similar constitutions, and a so-called solubility parameter (SP value) difference is ± 0.
Those of 5 are preferred.

The resin having a similar SP value can be achieved by that the resin used in the toner and the resin forming the adhesive layer on the transparent sheet have substantially the same composition. That is, when the toner resin is a styrene-acrylic resin, the resin forming the adhesive layer is also formed of a styrene-acrylic resin, and when the toner resin is a polyester resin, the resin forming the adhesive layer is also formed. It is preferably a polyester resin. Of course, resins having similar SP values can be used even without such a configuration.

The solubility parameter (SP) is Hildeb
It is defined by the following equation in the rand-Scatchard dissolution theory.

[0017]

[Equation 1]

However, Ev represents evaporation energy, V represents molecular volume, and Ev / V represents cohesive energy density.

The unit of the solubility parameter SP is (cal
/ Cm ³ ) ^1/2 .

There are various methods for obtaining the solubility parameter value. For example, the reference “RF Fedors, Polymer. Eng., 14, (2) 147” is used.
(1974) ”. That is, in the structural formula of the compound to be obtained, the following formula is used to calculate from the data of the evaporation energy of atoms and atomic groups and the molar volume.

[0021]

[Equation 2]

However, ei and Vi respectively represent an evaporation energy volume of an atom or an atomic group. In addition, regarding polyester resins, the literature “KWSuh, DHClarke, J. Polym.
ci., Part A-1, 5, 1671 (1967) ”. This is a method in which a non-solvent is added to a polymer solution and the solubility parameter value is determined by the amount of the non-solvent required until turbidity occurs.

As the resin constituting the toner or the adhesive layer, the SP value difference from the binder resin may be within a specific range. When this difference is large, the solubility at the interface decreases and the change in the refractive index increases.

When the binder resin is a polyester resin, the SP value of this is about 10.8, which can be achieved by using a similar polyester resin for the adhesive layer.
When a styrene acrylic resin is used as the binder resin of the toner, the SP value of this is about 9.2 to 9.7, and a styrene acrylic resin having a similar composition may be used as the adhesive layer. .

Constitution of Toner The toner used in the present invention uses a polyester resin, a styrene acrylic resin, a styrene butadiene resin or the like as a binder resin, and further contains a colorant, a release agent and other additives used as necessary. It is a toner in which inorganic fine particles are added and mixed to colored particles containing an agent. The average particle diameter is a volume average particle diameter of 1 to 30 μm, preferably 4 to 13 μm.
Is.

The color pigments and dyes used as colorants in the present invention include yellow pigments, magenta pigments,
Cyan pigments, red pigments and the like can be mentioned. As the yellow pigment, a benzidine yellow pigment is desirable. The benzidine-based yellow pigment is a yellow organic pigment of 3,3'-dichlorobenzidine derivative. In particular,
C. I. Pigment Yellow No. 12, the same 13, the same 14, the same 15, the same 1
7, ibid 55, ibid 83, ibid 174 (C.I No. 210)
90, 21100, 21095, 21105) and the like are mentioned as typical ones. As the magenta pigment, 2,9-dimethylquinacridone (CI Pigment Red 12) which is a quinacridone-based magenta pigment is used.
2), C.I. which is an azo lake magenta pigment. I. Pig
ment Red No. 57-1 etc. can be mentioned. As the cyan pigment, a copper phthalocyanine-based pigment is preferable. Specifically, C.I. I. Pigment Blu
e (Pigment blue) No. 15, the same 15-3, the same 15-4, the same 15-6, halogenated phthalocyanine and the like can be mentioned. As the red pigment, an insoluble monoazo pigment, an azo lake pigment, and a perylene pigment are desirable.
Specifically, C.I. I. Pigment Red 22, 48-1, 48-2, 48-
3, 53-1, 57-1, 112, 149, 178 and the like.

As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 1
22, C.I. I. Solvent Yellow 19, 44, 7
7, ibid 79, ibid 81, ibid 82, ibid 93, ibid 98, ibid 10
3, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 9
5 and the like can be used, and a mixture thereof can also be used. As the pigment, C.I. I. Pigment Red 5,
48: 1, 53: 1, 57: 1, 122, 1
39, 144, 149, 166, 177, 1
78, ibid. 222, C.I. I. Pigment Orange 31, the same 43, C.I. I. Pigment Yellow 14, Same 17 and Same 9
3, 94, 138, C.I. I. Pigment Green 7, C.I. I. Pigment Blue 15: 3, 60 and the like, and a mixture thereof can also be used. The number average primary particle size of the pigment itself varies depending on the type,
About 10 to 200 nm is preferable.

The volume average particle size is a value measured by a Coulter counter.

Further, it is necessary that the number of particles having a particle diameter equal to or smaller than the layer thickness of the adhesive layer formed on the transparent sheet is 10 number% or more. When this number ratio is small, the adhesiveness between the toner and the adhesive layer is reduced, and the improvement in transparency cannot be achieved.

The color toner of the present invention can be used as a two-component developer by mixing it with a carrier. As the carrier constituting the two-component developer, either an uncoated carrier composed only of magnetic material particles such as iron and ferrite, or a resin coated carrier in which the surfaces of the magnetic material particles are coated with a resin may be used. The volume average particle diameter of the carrier is preferably 30 to 150 μm.

Structure of Fixing Method Suitable fixing methods used in the present invention include (1) a heat roller fixing method and (2) a fixedly installed heating body, and pressure contact and rotation facing the heating body. A so-called film fixing method in which a toner image is heat-fixed on the recording material by a pressure member that presses the recording material onto the heating body via the film material can be used.

(1) The heat roller fixing method will be described with reference to the block diagram of FIG. The heat roller fixing device has a heat source 4 inside a metal cylinder 3 made of iron, aluminum or the like having a coating layer 2 of tetrafluoroethylene or polytetrafluoroethylene-perfluoroalkoxy vinyl ether copolymers on the surface. The fixing roller (upper roller) 1 and the pressure roller (lower roller) 5 made of silicone rubber or the like are provided. Specifically, a linear heater is provided as the heat source 4, and the surface temperature of the fixing roller 1 is heated to about 120 to 200 ° C. The recording material 6 carrying the toner image 7 made of the toner of the present invention is passed between the fixing roller 1 and the pressure roller 5 to fix the toner image 7 on the recording material 6 by heat fusion.

In the fixing section, pressure is applied between the fixing roller 1 and the pressure roller 5 to deform the pressure roller 5 and form a so-called nip. The nip width is 1 to 10 mm,
It is preferably 1.5 to 7 mm. The fixing linear velocity is 40 mm
/ Sec to 400 mm / sec is preferable. When the nip is narrow, heat cannot be uniformly applied to the toner, resulting in uneven fixing. On the other hand, when the nip width is wide, melting of the toner resin is promoted, and the offset phenomenon easily occurs. In the heat roller fixing device of the present invention, a fluorine-containing silicon oil coating film is formed on the coating layer 2 on the surface of the fixing roller 1. That is, the impregnating roller 8 is pressed against the coating layer 2 on the surface of the fixing roller 1 in the longitudinal direction, and is rotating in the direction of the arrow. This impregnating roller 8
Has been impregnated with fluorine-containing silicon oil in advance,
During fixing, fluorine-containing silicon oil is supplied to the surface of the fixing roller 1 from the impregnating roller 8 in minute amounts as the fixing roller 1 rotates, and a fluorine-containing silicon oil coating film is formed on the surface of the fixing roller 1.

(2) Next, the latter film fixing method will be described with reference to FIGS.

In the film fixing device shown in FIG. 2A, the low heating capacity linear heating element 15 fixedly supported by the main body of the fixing device has a thickness of 0.2 mm to 5.0 mm, preferably 0.5 mm. 3.5 mm, width 10 mm to 15 mm,
Alumina substrate 17 having a length of 240 to 400 mm in the longitudinal method
A resistance material is applied to 1.0 to 2.5 mm, and electricity is applied from both ends. The energization is given by changing the pulse width according to the temperature / energy release amount controlled by the temperature sensor 16 with a pulse waveform of DC 100 V and a cycle of 25 msec. In the case of the temperature T1 detected by the temperature sensor 16 in the linear heating element 15 having a low heat capacity, the surface temperature T2 of the film material 14 facing the resistance material is lower than T1. Here, T1 is preferably 120 ° C to 220 ° C, and the temperature of T2 is 0.5 ° C as compared with the temperature of T1.
It is preferably lower by 10 ° C. In addition, the film material 1 in the portion where the film material 14 is separated from the toner fixing surface
4 Surface temperature T3 is almost equal to T2. In this way, the fixing film (film material) 14 moves in the direction of the central arrow in FIG. Examples of the fixing film 14 include a heat-resistant film having a thickness of 10 μm to 35 μm, such as polyester, polyperfluoroalkoxy vinyl ether, polyimide, polyether imide, and at least a release material made of a fluororesin such as Teflon and a conductive material added thereto. It is an endless film having a layer coated with 5 to 15 μm. Generally, the total pressure is 10 μm to 100 μm, and the film material 14 is driven in the direction of the arrow without wrinkling or twisting by the driving and tension of the driving roller and the driven roller. The fixing linear velocity is 40 mm / sec to 400 mm / s
ec is preferred. The pressure roller 13 has a rubber elastic layer having a high releasability, such as silicone rubber, and is pressed against a heating body through the film material 14 at a total pressure of 2 to 30 kg to rotate under pressure.
By passing the recording material carrying the toner image between the film material 14 and the pressure roller 13, the toner image is fused and fixed to the recording material.

Further, in FIG. 2A, as in the case shown in FIG. 1, the impregnating roller 18 extends in the longitudinal direction of the film material 14 and the driven roller 12 via the film material 14.
It is pressed against and is rotating in the direction of the arrow. As the film material 14 moves, the impregnating roller 8 supplies a small amount of fluorine-containing silicon oil to the surface of the film material 14, and as a result, the surface of the film material 14 on the pressure roller 13 side is coated with a fluorine-containing silicon oil coating film. Is formed.

Still another example of the film fixing device is shown in FIG.
An explanation will be given using (B). The example of FIG. 2A is a fixing device having a structure using an endless film material 14,
FIG. 2B is a schematic configuration diagram of a fixing device including an end film material. Regarding the reference numerals used in the figure, the parts having the same functions as those in FIG. The points different from the above will be described.

Sheet feeding shaft 21 and winding shaft 22
The end film material 24 is wound around the recording medium 24, and the winding shaft 22 is driven every time one recording material is fixed, and the film material 24 is gradually moved in the arrow direction. A recording material carrying a toner image is passed between the end film 24 and the pressure roller 13, and a linear heating element 15 is passed to fuse and fix the toner image to the recording material. The impregnating roller 28 impregnated with fluorine-containing silicon oil is brought into pressure contact with the film delivery shaft 21 through the end film material 24,
A fluorine-containing silicone oil coating film is formed on the surface of the end film material 24 on the pressure roller side.

Further, the fixing device may have a simple cylindrical shape without a supporting roller such as a driving roller.

In any of the fixing devices described above, the fixing roller 1 or the film materials 14 and 24 may be provided with a fixing cleaning mechanism. As this method, a method of supplying a releasing agent such as so-called polydimethylsiloxane to the upper roller of the fixing or the film or an impregnated pad,
A method of cleaning with a roller or a web can be used.

[0041]

【Example】

[Transparent Sheet Production Example] The following adhesive layer was formed on a transparent sheet having a film thickness of 150 μm of polyethylene terephthalate formed by biaxial stretching. This adhesive layer was formed by applying a resin forming an adhesive layer using various solvents with a wire bar and drying.

[0042]

[Table 1]

[Toner Production Example] As a toner, 100 parts of a binder resin shown below, 8 parts of a colorant shown below and 3 parts of a low molecular weight polypropylene were melt-kneaded, pulverized and classified to obtain colored particles, and further, a hydrophobic particle Was added 1.0% by weight of volatile silica to obtain a toner. The table below shows the toner composition.

With the Y toner (yellow toner), C.I. I. Pigment Yellow 17 with C toner for M toner (magenta toner). I. Pigment
Red 122 is C. toner with C toner (cyan toner).
I. Pigment Blue 15: 3, and carbon black was used as a colorant in the black toner.

[0045]

[Table 2]

[0046]

[Table 3]

A styrene-acrylic resin-coated ferrat carrier having a volume average particle size of 65 μm was mixed with the above toner to prepare a developer having a toner concentration of 7%. The developers prepared below are shown.

[0048]

[Table 4]

A digital full-color copying machine 7728 manufactured by Konica Corporation was modified and used as an evaluation machine. Below are the details of the modification related to the fixing conditions. In the evaluation, the above-mentioned transparent sheet and each toner were combined and fixed, and the transparency was compared by the transmittance. Image is 7% for each color
The full-color image which becomes the pixel of was printed. Transmittance is 60
When it is at least%, the image has high transparency. The transmittance was measured with a Hitachi U-3500 self-recording spectrophotometer, and depending on each color, the yellow toner was 570 nm, the magenta toner was 630 nm, and the cyan toner was 500.
The transmittance in nm was measured and the average value was calculated. The results are shown in the table below.

[0050]

[Table 5]

[0051]

[Table 6]

[Fixing Conditions for Hot Roll] As a hot roll method, the surface was covered with a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and the diameter was 30 mmφ.
Has a cylindrical iron having a built-in heater in the center as an upper roller, and has a lower roller having a diameter of 30 mmφ made of silicone rubber whose surface is similarly coated with tetrafluoroethylene-perfluoroalkyl ether copolymer. are doing. The linear pressure was set to 0.8 kg / cm and the width of the nip was 4.3 mm. Using this fixing device, the linear velocity of printing was set to 250 mm / sec. As a cleaning mechanism of the fixing device, a pad impregnated with silicone oil made of polydimethylsiloxane was attached and used.

[Film-like Fixing Condition] The fixing condition was set as follows by using the endless sheet fixing device (film-like fixing device) shown in FIG.

Fixing conditions Temperature T1 of heating body 15 = 180 ° C. Moving speed of film material 14 = 250 mm / sec Total pressure between heating body 15 and pressure roller 13 = 10 kg Nip between pressure roller 13 and film material 14 = 3 mm Film material 14: Polyimide film material with a thickness of 15 μm, which is coated with polytetrafluoroethylene in which a conductive material is dispersed. A cleaning mechanism of the fixing device is equipped with a pad impregnated with polydimethylsiloxane silicon oil. Used.

[0055]

According to the image forming method of the present invention, a highly transparent color toner image can be formed on a transparent sheet.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a heat roller fixing device applied to an image forming method of the present invention.

FIG. 2 is a schematic configuration diagram of an endless film fixing device and an end film fixing device applied to the image forming method of the present invention.

[Explanation of symbols]

 1 fixing roller (upper roller) 4 heating source 5,13 pressure roller (lower roller) 6 recording material 8,18,28 impregnation roller 11 drive roller 12 driven roller 14,24 film material (fixing film) 15 linear heating element

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiki Nishimori Konica Co., Ltd. 2970 Ishikawa-cho, Hachioji-shi, Tokyo

Claims (3)

[Claims] 1. An image forming method using a transparent sheet having an adhesive layer on a translucent sheet as a toner image support, wherein the adhesive layer has a layer thickness of 2 to 10 μm, and the toner has an adhesive layer. The image forming method is characterized in that 10% by number or more of particles having a particle diameter equal to or less than the layer thickness are present. 2. The image forming method according to claim 1, wherein the toner is a color toner. 3. A method of thermally fixing a toner image support carrying a toner image on a transparent sheet having an adhesive layer on a translucent sheet between a fixing member and a pressure member for heat fixing. Has a layer thickness of 2 to 10 μm, and 10% by number or more of the toner has a particle diameter equal to or smaller than the layer thickness of the adhesive layer.