JP3478278B2 - Multicolor image forming method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a multicolor image by electrophotography and electrostatic recording.

[0002]

2. Description of the Related Art Conventionally, when a color image is formed by an electrophotographic method, for example, it is performed as follows. First,
The reflected light from the original is color-separated by a color CCD, and image processing and color correction are performed by an image processing device to obtain image signals of a plurality of colors. A plurality of electrostatic latent images are formed by irradiating the photosensitive member with the signal for each color a plurality of times as a laser beam modulated by using a semiconductor laser for each color. For example, these are sequentially developed with four color toners of Y (yellow), M (magenta), C (cyan), and K (black), and these toner images are transferred from the photoconductor to a transfer body such as paper. Transcribe. Then, the transferred image is heated and fixed by a heat fixing roll or the like to form an image.

In the color image obtained by such a method or the like, the particle shape of the fixed toner remains, and the transfer body is impregnated into the transfer body (for example, paper) with the binder resin or the colorant. The uneven shape of itself remains, and it has an irregularly rough surface shape as compared with an image obtained by printing or a silver salt photographic method. For this reason, diffuse reflection occurs on the image surface, and even if a high-dispersion pigment or a small particle size toner is used so that the particle shape of the toner is not reflected in the image as much as possible, the graininess, gloss, and even the color tone are not affected. I know that it will result in a bad image.

The shape of the toner particles and the degree of the influence of the unevenness of the transfer material greatly differ depending on the density of the image. Depending on the type of the image such as the background portion, the low density portion and the high density portion, the gloss, graininess and color tone of the image are Etc. have changed, resulting in an unnatural image without smoothness compared to the image obtained by printing or silver halide photography.

Further, the degree of the influence of the unevenness of the transfer material largely varies depending on the type of the transfer material, and it is difficult to obtain high image gloss and graininess with the transfer material having a rough surface and having a low price. .

In order to solve the above-mentioned problems, when the amount of developer is simply increased, unevenness of the transfer material is less likely to be reflected on the surface after fixing in a high density portion, and high gloss is obtained, but non-image The effect cannot be obtained in the part (background part). Further, when the amount of the developer is increased, the charge amount of the toner is generally lowered, so that the background portion is fogged.

Therefore, in order to solve the above problems, for example, JP-A-63-58374 and JP-A-4-27 are used.
8967, JP-A-4-204669, 4-2046.
70, JP-A-7-72696, and JP-A-5-2328.
No. 40, a method of transferring and fixing a transparent toner to a transfer member in addition to the color toner, and JP-A-63-9296.
No. 4,92965, a method of coating a transparent resin on the transfer body in advance has been proposed.

[0008]

However, in these methods, the toner is excessively melted by fixing, so that the transfer material (for example, paper) is soaked into the toner, or the toner is not sufficiently melted and the toner particle shape remains. Problems such as being lost occur. That is, the mechanical irregularity shape of the image surface is not controlled, and due to irregular reflection on the surface, sufficient graininess and gloss are not achieved, and the expected effect cannot be obtained.

Thus, according to the present invention, a high-quality image having appropriate gloss, good graininess, high color tone and smoothness, similar to printing or silver halide photography, can be obtained by an electrophotographic method regardless of the type of the image. An object of the present invention is to provide a multicolor image forming method capable of being uniformly reproduced on a transfer body.

[0010]

The inventors of the present invention have made extensive studies as to how to achieve the above-mentioned object, and as a result, a color image obtained by using a color copying machine which is an electrophotographic system is a silver salt photograph. Compared with the color image obtained by the method or high-quality printing, there is a large difference in the surface roughness, especially in the image area, non-image area, and intermediate density area. The present invention has been completed by finding that the image gloss and graininess can be improved not only by providing the image portion and the image portion but also by controlling the surface roughness thereof to a specific fineness.

That is, the present invention further comprises a step of fixing the transparent toner layer on the image portion and the non-image portion in the multicolor image forming method having a step of fixing a plurality of colored toner layers as an image on the transfer member. The average surface roughness (Ra) of the fixed layer is 0.0 <Ra <1.5 μm and / or the maximum surface roughness (Rmax) is 0.0 <Rmax <1.
It is characterized in that it is 0 μm.

In the present invention, since the surface roughness of the fixed image becomes a specific fineness over the entire image, scattering of light on the image surface can be suppressed, and the above object can be effectively achieved. It is thought to be.

In the present invention, the transparent toner layer is provided not only in the non-image portion but also in the image portion formed by the color toner layer.
The transparent toner layer may be provided on or below the colored toner layer. In any case, the layer after being fixed has a function of not reflecting the unevenness of the transfer body (for example, paper),
The surface roughness can be kept within the range specified in the present invention. The transparent toner layer is preferably provided on the colored toner layer. In this case, the obstacle to the formation of the color toner layer is reduced, and the disturbance of the image can be eliminated.

Further, in the present invention, preferably, the surface average roughness (Ra) when the colored toner layer and the transparent toner layer are provided and fixed is determined when the colored toner layer is provided and the transparent toner layer is not provided. For surface average roughness (Ra '),
0.0 <Ra <0.7Ra ', or the maximum surface roughness (Rmax) when the colored toner layer and the transparent toner layer are fixed and fixed is fixed without the colored toner layer and the transparent toner layer. With respect to the maximum surface roughness (Rmax ′) at the time, 0.0 <Rmax <0.7Rmax ′.

The process of "fixing with a colored toner layer and fixing without a transparent toner layer" is a process used for reference, and the process alone does not fall within the scope of the present invention. Absent. That is, the process is performed by performing the same method as that of the present invention except that the transparent toner layer is not provided, and is a reference for determining the preferable range of the method of the present invention.

In the present invention, it is preferable that the relationship between the thickness T of the transparent toner layer and the thickness t of the thickest color toner layer among the plurality of color toners satisfies 3t>T> 0.5t. .

Further, in the present invention, the transparent toner has a viscosity at the time of fixing of 10 ¹ to 10 ⁴ Pa.s. It is preferably formed of a resin of sec.

Further, in the present invention, it is preferable that the transparent toner has inorganic fine particles and / or resin fine particles adhered to the surface thereof. When inorganic fine particles are attached to the surface of the transparent toner, the refractive index of the inorganic fine particles is n, the refractive index of the binder resin is N, and the weight ratio of the inorganic fine particles to the binder resin is W. In each case, it is particularly preferable that the following formula is satisfied. -4 ≦ (n−N) × W × 100 ≦ 4

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to embodiments.

The multicolor image forming method of the present invention is an invention relating to the improvement of the method of fixing a plurality of colored toner layers as an image on a transfer body, and the method itself is any method that can be used in the art. May be used.

In the method of the present invention, the transparent toner layer is fixed on the image area and the non-image area, and the granularity, glossiness and uniformity of the fixed layer (that is, the fixed color toner layer and the fixed transparent toner layer) are fixed. To obtain the average surface roughness Ra and the maximum surface roughness Rmax of the fixed layer, 0.0 <R
a <1.5 μm and / or 0.0 <Rmax <10
It is indispensable to set it to μm. It was found that an image in which Ra exceeds 1.5 μm and Rmax <10 μm causes diffuse reflection on the surface and disturbs graininess, resulting in low gloss and poor color reproducibility.

In the method of the present invention, the surface average roughness Ra when the color toner layer and the transparent toner layer are provided and fixed is fixed.
However, it is preferable that 0.0 <Ra <0.7Ra 'is satisfied with respect to Ra' when the color toner layer is fixed and the transparent toner layer is not fixed. Further, the maximum surface roughness Rmax when the color toner layer and the transparent toner layer are provided and fixed is Rma when the color toner layer is provided and the transparent toner layer is not provided.
It is desirable that 0.0 <Rmax <0.7Rmax ′ for x ′. In this way, the unevenness of the transfer member is reduced by the transparent toner layer, so that the gloss in the white background is improved, and a smoother, more uniform and more preferable image of high quality can be obtained regardless of the image density. I understood.

Although any method may be used for controlling the roughness of the surface of the fixed image within the specific range defined in the present invention, the following method is preferable.

As a first method for controlling the surface roughness, the thickness T of the transparent toner layer is 3t>T> with respect to the thickness t of the thickest colored toner layer among the plurality of colored toners.
One example is to satisfy 0.5t. By this method, after fixing, there is no step in the image at the boundary between the background portion (non-image portion) and the high-density portion, the surface roughness in the specific range is easily obtained, and diffuse reflection at the image interface is eliminated, resulting in a uniform image. An image with gloss is obtained. T <0.5t
When it becomes, it is difficult to obtain the surface roughness in the specific range, the step at the boundary of the fixed image is large, the effect of improving the graininess is small, and the unevenness of the paper is wiped in the white background / low density area. Therefore, there is a strong tendency that only images with low gloss and poor graininess can be obtained. Further, when 3t <T, an offset is likely to occur during fixing, and the life of the fixing device is shortened.

As a second method for controlling the surface roughness, the viscosity of the resin forming the transparent toner at the time of fixing may be changed. Although the specific method is not limited, for example, the molecular weight of the resin used in the toner is changed.
In order to make the surface roughness fine, a resin having a small molecular weight may be used. Further, as another method, the amount of the crosslinking component in the resin used is changed. In order to make the surface roughness fine, a resin having a small amount of the cross-linking component may be used.
Furthermore, as another method, the viscosity is changed by changing the molecular structure of the resin used.

The viscosity of the resin for obtaining the predetermined surface roughness of the present invention is 10 ¹ to 10 ⁴ Pa.s at the time of fixing. It is preferably sec. 10 ¹ Pa. If it is less than sec, offset is likely to occur when the toner is fixed on the fixing roll. Further, when fixed in an oven or the like, no offset occurs, but the mechanical strength of the fixed image is weak, and cracks when bent and image defects when rubbed are likely to occur. Also,
10 ⁴ Pa. If it exceeds sec, the surface roughness of the image after fixing tends to be larger than the predetermined value of the present invention.

The resin for the transparent toner layer formed by the method of the present invention includes polyester, polystyrene, polyacryl, polyolefin, polycarbonate,
It may be appropriately selected from all resins used in the art for general toner such as polyamide-based, polyimide-based, epoxy-based, and polyurea-based toners in consideration of transparency and the like. Considering not only transparency but also mechanical strength and the like, a polyester resin is preferable.

It is preferable that the surface roughness of the fixed image formed by the method of the present invention is uniform and uniform, and for that purpose, it is important to control the fluidity and chargeability of the transparent toner. For this purpose, inorganic fine particles and / or resin fine particles are usually attached to the surface of the transparent toner. The type of the inorganic fine particles and the resin fine particles is not particularly limited as long as it exhibits a desired action, but as an example of the inorganic fine particles, silica,
Examples thereof include titanium dioxide, tin oxide, molybdenum oxide and the like. Further, in consideration of the stability such as dispersibility, those subjected to a hydrophobic treatment with a silane coupling agent, a titanium coupling agent or the like can be used. On the other hand, examples of the organic fine particles include fine particles of polyester type, polystyrene type, polyacrylic type, polyolefin type, polycarbonate type, polyamide type, polyimide type, epoxy type, polyurea type, fluorine type and the like.

The particle size of the above-mentioned inorganic particles and / or resin particles is preferably 0.005 to 1 μm. If the particle size is less than 0.005 μm, agglomeration easily occurs when attached to the surface of the transparent toner, and the expected effect is difficult to be obtained. Further, when the particle size exceeds 1 μm, the roughness of the surface of the fixed image tends to fall outside the predetermined range of the present invention.

Further, in order to enhance the effect of the present invention (specifically, the effect of smoothing the surface), the refractive index n of the inorganic fine particles adhered to the surface of the transparent toner, the refractive index N of the binder resin, and The relationship between the weight ratio W of the inorganic fine particles to the binder resin is preferably −4 ≦ (n−N) × W × 100 ≦ 4. When the value of (n−N) × W × 100 is out of the specified range, light scattering at the interface between the inorganic fine particles and the binder resin becomes large, and the roughness of the image surface falls within the desired range, but the color of the image is reduced. To a lesser degree, and a favorable image cannot be formed.

Further, for the purpose of enhancing the effect of the present invention in which the surface roughness is smoothed, it is preferable to suppress irregular reflection at the interface between the pigment and the binder of the colorant contained in the toner,
The combination of the use of a colorant in which a pigment having a small particle size is highly dispersed and the essential requirements of the present invention realizes the object. The same purpose is effectively achieved by the combination of the use of small particle size toner and the essential requirements of the present invention. It has been found that when the toner particle size is larger than 9 μm, the toner particles are recognized and the graininess is significantly disturbed, and the effect of reducing the scattering on the surface is not sufficiently obtained. However, when the toner particle size is less than 1 μm, the amount of the toner charged to the opposite polarity increases, causing fog on the background portion, and a satisfactory image cannot be obtained.

In consideration of color reproducibility, the surface roughness of the fixed layer is preferably finer than the above-specified range, and in that case, it is important that 0.0 <Ra <0.5 μm. is there. If it exceeds 0.5 μm, the surface roughness becomes equal to or more than the wavelength of light, and surface scattered light occurs. This light beam is not absorbed by the image and thus reduces the density of the image.

In order to achieve the above preferable surface roughness, a substrate having a surface layer containing at least a binder resin and having a surface roughness of 0 to 0.7 μm is typically used, and further, A non-contact type oven or a radiant fixing device is used as the step of fixing the transparent toner. In order to obtain a sufficiently fine surface roughness, it is preferable to fix the toner for a long time by a non-contact type oven or a radiant fixing device under the condition that the toner viscosity is sufficiently lowered. In this case, in order to prevent the melted toner from flowing into the gaps between the fibers of the base material, it is preferable to use a base material having a surface layer containing at least a binder resin.

Next, a method of providing the transparent toner layer will be described. The method is arbitrary as long as it can realize the essential requirements specified in the present invention. However, in consideration of the matters explained so far, the following will be described. The method illustrated in FIG.

For example, as shown in Japanese Patent Laid-Open No. 63-58374, as in the color toner developing method, a transparent toner previously mixed and charged with a carrier is put in a developing device and brought close to the photosensitive member. An electrostatic latent image is formed on it, and the latent image is developed by electrostatic force.
The image is transferred onto the transferred transfer material by electrostatic force, and the transfer image is heated and fixed by a fixing roll.

As another method, first, the latent image on the photosensitive member is first developed with a transparent toner, then charged and exposed again, and the image is developed with a color toner. This is repeated by the number of color toners to form a plurality of toner layers on the photoconductor. Then, there is a method in which the particles are collectively transferred to a transfer body by electrostatic force and heated and fixed by a fixing roll.

The color toner that can be used in the method of the present invention may be selected from any type available in the art. For example, polyester resin, styrene / acrylic copolymer, styrene / butadiene copolymer. In a binder resin such as, etc., a pigment as a colorant is dispersedly contained in particles having an average particle size of 1 to 15 μm, preferably particles having an average particle size of 1 to 9 μm, for example, silicon oxide, titanium oxide,
It is possible to use inorganic fine particles having an average particle diameter of 5 to 100 nm such as aluminum oxide, or those obtained by adhering resin fine particles such as PMMA and PVDF.

Although the above-mentioned coloring pigments are also optional, for example, Y (yellow) coloring agents; benzidine yellow, quinoline yellow, Hansa yellow M (magenta) coloring agents; rhodamine B, rose bengal, pigment red C (cyan) coloring agents. Phthalocyanine blue, aniline blue, pigment blue K (black) colorant; carbon black, aniline black, a blend of color pigments and the like may be used.

The surface roughness (Ra,
Rmax) is measured by a surface roughness meter, Perthomet
er C5D (Perthen), needle tip diameter 2
Scanning speed 0.5 mm / sec, measuring length 1.0 mm, measuring pitch 1 μm, cut-off 0.8 mm with μm needle
Rai and Rmaxi are obtained under the conditions of, and a region of 0.25 mm is measured 50 times in a direction perpendicular to the scan at a measurement pitch of 5 μm, and the average value thereof is taken as Ra and Rmax. Rai,
Rmaxi, an image analyzer SAS-2 for calculating the average value
010 (manufactured by Meishin Koki) is used.

[0040]

EXAMPLES The present invention will be described more specifically below with reference to examples. Evaluation method in each example and comparative example: Evaluation of graininess was performed by visual evaluation using uniform images of 2 × 2 cm having different average reflection densities. Targeting 20 evaluators, 1. Very rough 2. Coarse texture, 3. Usually, 4. Fine texture, 5. We asked them to classify them into five, which were very fine, and calculated the average value. The case where the average value is less than 2 is indicated by x, the case where the average value is 2 or more and less than 4 is indicated by Δ, and the case where the average value is 4 or more is indicated by o.

The color reproducibility is measured by X-rite 404 (X
-Rite), and magenta image density 100%
The image density in the area was measured to be less than 1.4 ×, 1.4 or more and less than 1.7 Δ, 1.7 or more ◯.

The sensory evaluation of the entire image was carried out by visual evaluation of a portrait photograph. Targeting 20 evaluators, 1. Very bad 2. Bad 3. Usually, 4. Good, 5. They were classified into 5 types, which were very fine and good, and the average value was calculated. The case where the average value is less than 2 is indicated by x, the case where the average value is 2 or more and less than 4 is indicated by Δ, and the case where the average value is 4 or more is indicated by o.

Gloss is used to measure the specular gloss.
s Meter GM-26D (Murakami Color Research Laboratory)
Was used. The incident angle of light with respect to the image was 75 degrees.

A rotary flat plate rheometer RD-
2 (manufactured by Rheometrics Inc.), the measurement temperature was set to the same value by measuring the toner temperature during actual fixing, and the viscosity at a dynamic viscoelastic frequency of 0.1 rad / sec was obtained. And compared.

The molecular weight was measured by gel permeation chromatography. Tetrahydrofuran was used as the solvent.

The average particle size of the toner was measured using a Coulter counter, and the weight average d ₅₀ was applied.

The average particle size of the fine particles added to the toner surface is 10
10 particles were photographed with a reflection electron micrograph.
The value of 1/2 of the sum of 0 long diameters and short diameters was obtained, and the average value was adopted.

Example 1 (Colored toner) As the colored toner, cyan, magenta, yellow and black toners for A-color products manufactured by our company were used.

(Method for producing transparent toner A) Binder resin: linear polyester obtained from terephthalic acid / bisphenol A ethylene oxide adduct / cyclohexanedimethanol (Tg = 62 ° C., Mn = 4000,
Mw = 35000), viscosity 5 × 10 ² Pa. sec, Refractive index 1.5 After pulverizing the above materials with a jet mill, classification was carried out with an air classifier to prepare a transparent toner having d ₅₀ = 7 μm. The following two types of inorganic fine particles were attached to this surface with a high-speed mixer. Inorganic fine particles A; SiO ₂ (hydrophobicizing the surface with a silane coupling agent), average particle diameter 0.05 μm, refractive index 1.
6, addition amount 1.1 parts by weight, inorganic fine particles B; TiO ₂ (hydrophobicizing the surface with a silane coupling agent), average particle size 0.02 μm, refractive index 2.
5, 1.4 parts by weight

(Method for producing developer) Spherical ferrite particles having a particle size of about 50 μm coated with a styrene-methylmethacrylate copolymer were used as a carrier, and 8 parts by weight of 100 parts by weight of the carrier for both colored and transparent toners were used. Parts were added and mixed with a tumbler shaker mixer to obtain a two-component developer.

(Image Producing Method) In this embodiment, Fuji Zero
Cox Co., Ltd. color copier A-color630
The apparatus shown in FIG. 1 which was modified was used. This
In this device, the illumination 1 illuminates the original 2 and the reflected light
Is read by the color CCD 3 and the image processing device 4
Signals that have undergone color separation into three colors of Y, M, and C and have undergone image processing
As for each color, the optical signal from the semiconductor laser 5 is sequentially output.
Output as. The optical signal is transmitted through the optical system 6 and stored in advance.
Therefore, the photoconductor 8 charged by the charger 7 is irradiated.
In this way, an electrostatic latent image in which the image part has a low potential is created,
The developer of the charged colored toner obtained by the above method was developed.
Applying a developing bias to the image units 9 to 12
To develop colored toner on the photoreceptor by electrostatic force.
It was The developed toner is electrostatically attracted to the transfer drum 13.
Each color is given to the base material 14 formed by the transfer with the transfer corotron 15.
Transferred by the applied electric field. This is 3 in order of Y, M, C
Repeated three times, a color toner image with three colors superimposed on the transfer material
Got Next, the transparent toner and the carrier are mixed to obtain
The charged charged developer is charged into the developing device 16 and
Clear toner is applied on the photoconductor that has been exposed to light by applying Iias.
Was uniformly developed by electrostatic force. This on the transfer material
Transferred by electrostatic force on the formed color toner image
Then, it is heated and fixed by the fixing device 17 to obtain a color image.
It was The toner temperature during fixing was 120 ° C. Well
In addition, the base material used for the measurement was manufactured by Fuji Xerox Co., Ltd.
Color paper (trade name: J paper) was used. Color developed
The toner weight is 0.72 (mg
/ Cm ²), The development weight of the transparent toner is 0.75 (mg /
cm²).

Example 2 Example 1 except that the binder resin of the transparent toner was changed to the following
A color image was prepared in the same manner as in. Binder resin: linear polyester obtained from terephthalic acid / bisphenol A ethylene oxide adduct / cyclohexanedimethanol (Tg = 65 ° C., Mn = 8000,
Mw = 50000), viscosity 5 × 10 ³ Pa. sec, refractive index 1.5

Example 3 A color image was prepared in the same manner as in Example 1 except that the fine particles attached to the surface of the transparent toner were replaced with the following materials in an amount of 1.5 parts by weight.・ Surface-adhered fine particles; polymethylmethacrylate, particle size 0.8 μm, refractive index 1.4

Example 4 Using a printing art paper "Kinto" (manufactured by Shin-Oji Paper Co., Ra = 0.3 μm) as a base material for image production, the step of fixing the transparent toner was carried out in an oven at 170 ° C. A color image was prepared in the same manner as in Example 1 except that the color image was placed for 10 seconds.

Example 5 A color image was prepared in the same manner as in Example 1 except that the amount of the inorganic fine particles B attached to the surface of the transparent toner was changed to 5 parts by weight.

Example 6 A color image was prepared in the same manner as in Example 1 except that the magenta toner among the color toners was prepared as follows. When the dispersed state of the color material of the produced magenta toner was observed with a transmission electron microscope, many color material aggregates of about 1 to 3 μm were observed. Binder resin: linear polyester obtained from terephthalic acid / bisphenol A ethylene oxide adduct / cyclohexanedimethanol (Tg = 62 ° C., Mn = 4000,
Mw = 35000), viscosity 5 × 10 ² Pa. sec, refractive index 1.5 ・ Colorant; same as A-color color material except not treated.

The above materials were kneaded with an extruder, pulverized with a jet mill, and then classified with a wind classifier to give d ₅₀
= 7 μm magenta toner was prepared. The following two types of inorganic fine particles were attached to this surface with a high-speed mixer. Inorganic fine particles A; SiO ₂ (hydrophobicizing the surface with a silane coupling agent), average particle diameter 0.05 μm, refractive index 1.
6, addition amount 1.1 parts by weight, inorganic fine particles B; TiO ₂ (hydrophobicizing the surface with a silane coupling agent), average particle size 0.02 μm, refractive index 2.
5, 1.4 parts by weight

Example 7 A color image was prepared in the same manner as in Example 1 except that the color toner had an average particle size of 11 μm.

Comparative Example 1 Using the colored toner and carrier shown in Example 1, a color image was prepared with the apparatus shown in Example 1 without using a transparent toner.

Comparative Example 2 The weight of developed colored toner is the maximum at image density.
0.72 (mg / cm ²), The development weight of transparent toner is
0.3 (mg / cm²). Except for this, as in Example 1
Similarly, a color image was prepared.

Comparative Example 3 Example 1 except that the binder resin of the transparent toner was changed to the following
A color image was prepared in the same manner as in. Binder resin: linear polyester obtained from terephthalic acid / bisphenol A ethylene oxide adduct / cyclohexanedimethanol (Tg = 70 ° C., Mn = 1000)
0, Mw = 60,000), viscosity 5 × 10 ⁴ Pa. se
c, refractive index 1.5

Comparative Example 4 A color image was prepared in the same manner as in Example 1 except that the inorganic fine particles were not attached to the surface of the transparent toner.

Comparative Example 5 A color image was prepared in the same manner as in Example 1 except that the following materials were used instead of the fine particles attached to the surface of the transparent toner.・ Surface-adhered fine particles; polymethylmethacrylate, particle size 1.2 μm, refractive index 1. 4 2.0 parts by weight

Comparative Example 6 The step of fixing the transparent toner was performed in an oven at 170 ° C.
A color image was prepared in the same manner as in Example 1 except that the color image was set for 0 seconds.

The evaluation results of the images obtained in Examples 1 to 7 are shown in Table 1. The evaluation results of the images obtained in Comparative Examples 1 to 6 are shown in Table 2.

[0066]

[Table 1]

[0067]

[Table 2]

[Evaluation] Each of the examples provided with the transparent toner layer, and each of the high-density portion, the low-density portion, and the white background portion (non-image portion) exhibiting the surface roughness prescribed by the present invention has a granular property, Although the glossiness, the color reproducibility and the sensory evaluation are all good, in each of the comparative examples which do not exhibit the surface roughness prescribed by the present invention, one or more of them is a bad result.

[0069]

According to the present invention described above, it is possible to eliminate light diffusion on the image surface in the electrophotographic system, has an appropriate luster, has good graininess, and has a high color tone and a high smoothness. A high-quality multicolor image can be uniformly formed on a transfer body regardless of the type of image.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a multicolor image forming apparatus used in an example.

[Explanation of symbols]

1 lighting 2 manuscripts 3 color CCD 4 Image processing device 5 Semiconductor laser 6 Optical system 7 charger 8 photoconductor 9-12 Color toner developing device 13 Transfer drum 14 Base material 15 Transfer Corotron 16 Transparent toner developing device 17 Fixer

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI G03G 9/087 G03G 15/00 303 9/09 15/01 J 15/00 303 9/08 321 15/01 361

Claims (7)

(57) [Claims] 1. A multicolor image forming method including a step of fixing a plurality of colored toner layers as images on a transfer member,
The method further comprises the step of fixing the transparent toner layer on the image area and the non-image area, and the surface average roughness (Ra) in the fixed layer.
Is 0.0 <Ra <1.5 μm and / or the maximum surface roughness (Rmax) is 0.0 <Rmax <10 μm. 2. A multicolor image forming method including a step of fixing a plurality of color toner layers as images on a transfer body,
The method further comprises the step of fixing the transparent toner layer on the image portion and the non-image portion, and the surface average roughness (Ra) when the colored toner layer and the transparent toner layer are fixed and fixed is determined by setting the colored toner layer and the transparent toner layer. Surface average roughness (R
2. The multicolor image forming method according to claim 1, wherein 0.0 <Ra <0.7Ra 'is satisfied with respect to a'). 3. A multicolor image forming method including a step of fixing a plurality of colored toner layers as an image on a transfer member,
The method further includes a step of fixing the transparent toner layer on the image area and the non-image area, and the maximum surface roughness (Rmax) when the colored toner layer and the transparent toner layer are provided and fixed is determined by providing the colored toner layer and the transparent toner layer. Maximum surface roughness (R
max '), 0.0 <Rmax <0.7Rma
The multicolor image forming method according to claim 1, wherein x ′ is set. 4. The thickness T of the transparent toner layer and the thickness t of the thickest color toner layer among the plurality of color toners,
4. The multicolor image forming method according to claim 1, wherein the relationship of 3t>T> 0.5t is satisfied. 5. The transparent toner has a viscosity of 10 when fixed.
¹ to 10 ⁴ Pa. The multicolor image forming method according to any one of claims 1 to 4, wherein the multicolor image forming method is formed of a resin of sec. 6. The multicolor image forming method according to claim 1, wherein the transparent toner has inorganic fine particles and / or resin fine particles adhered to the surface thereof. 7. The transparent toner has inorganic fine particles adhered to the surface thereof, and the refractive index of the inorganic fine particles is n, the refractive index of the binder resin is N, and the binder resin of the inorganic fine particles is When the weight ratio to W is W,
The multicolor image forming method according to claim 1, wherein the following formula is satisfied. -4 ≦ (n−N) × W × 100 ≦ 4