JP2001092171A - Multicolor image forming method and multicolor image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain multicolor images having adequate gloss and high image quality by an electrophotographic system relating to a multicolor image forming method and a multicolor image forming device. SOLUTION: In the process for fixing plural toner layers as images on a medium to be recorded, the silicone oil subjected to temperature control in such a manner that its viscosity attains >=0.1 poise and its surface tension attains <=15.0 dyn/cm is adhered to the surface of the fixed toner layers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor image forming method and a multicolor image forming apparatus, and more particularly to a toner layer for obtaining a high quality multicolor image having an appropriate glossiness in an electrophotographic system. TECHNICAL FIELD The present invention relates to a multicolor image forming method and a multicolor image forming apparatus characterized in that the viscosity and surface tension of silicone oil applied on a multicolor image are controlled.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic printer has been employed as a means for imaging various types of information, or an electrophotographic copying machine has been frequently used for copying various types of information. An image forming apparatus using a method generally uses a photoconductive insulator, that is, a method using a photosensitive drum.

In this method, an electrostatic latent image is formed by irradiating a laser light or the like to the surface of a photoconductive insulator uniformly charged by a corona or a charging roller, and a pigment called toner is formed on the latent image. A latent image is visualized as a toner image by applying electrostatically a resin powder colored with a dye or a dye, transferring the toner image onto a recording medium such as paper or film, and then heating the toner image. Thus, the toner is melted and fixed to obtain a visible image.

When forming a multicolor image, Y
These processes are repeated for each color of (yellow), M (magenta), C (cyan), and B (black) to form a color toner image, and the toner image is formed by using a heat fixing roller coated with a fluororesin. The toner is fixed by melting the resin contained in the toner.

In the fixing process using such a heat fixing roller, silicone oil is used as a release agent in order to prevent a hot offset phenomenon, that is, a phenomenon in which molten resin adheres to the heat fixing roller.

The use of silicone oil in such a fixing system is intended to reduce hot offset. For example, in Japanese Patent Application Laid-Open Nos. 11-143279 and 9-73247, the surface of the silicone oil is disclosed. The tension is specified.
No. 0 specifies the surface tension and viscosity of silicone oil at room temperature.

[0007]

However, in the above method, the purpose is only to prevent the hot offset phenomenon in which the toner adheres to the heat fixing roller. There is a problem that sufficient gloss cannot be achieved.

Accordingly, an object of the present invention is to obtain a high-quality multicolor image having an appropriate gloss by an electrophotographic method.

[0009]

Here, means for solving the problems in the present invention will be described. For easier understanding, reference is made to FIG. FIG. 1 is a correlation diagram between surface tension and viscosity in each example. Examples in which favorable results were obtained are indicated by black diamonds as examples, and examples in which sufficient gloss was not obtained are comparative examples. This is indicated by a black square. See FIG. 1. (1) The present invention relates to a method for forming a multicolor image having a process of fixing a plurality of toner layers as images on a recording medium, wherein the surface of the fixed toner layer has a viscosity of 0.1 poise or more. And a silicone oil whose temperature is controlled so that the surface tension is 15.0 dyn / cm or less.

Judging from the distributions of the embodiment and the comparative example shown in FIG. 1, the surface of the fixed toner layer has a viscosity of 0.1 poise or more and a surface tension of 15.0 dyn / cm or less. By applying a silicone oil whose temperature is controlled to the surface, the gloss can be increased by 5% or more before and after the application of the silicone oil, thereby obtaining an image having an appropriate gloss and less gloss unevenness. Can be. That is, by adhering silicone oil to the surface of the image, the average surface roughness of the toner layer can be reduced. For example, when the average surface roughness (R _a ) is 1.5
μm or less, more preferably a surface average roughness of 0.55 μm or less (gloss of 80 or more) at which a glossiness equivalent to that of a photograph can be obtained, whereby the reflectance on the surface of the toner layer is increased to increase the gloss. Can increase.

(2) Further, according to the present invention, in a multicolor image forming method having a process of fixing a plurality of toner layers as an image on a recording medium, the surface of the toner layer during the fixing process has a viscosity of 0%. .1 poise or more and surface tension of 1
It is characterized in that a silicone oil whose temperature is controlled so as to be 5.0 dyn / cm or less is adhered.

As described above, the silicone oil may be adhered to the toner layer during the fixing process, and if the silicone oil contained on the surface of the heat roller is adhered at the time of fixing by the heat fixing roller. good.

(3) In the present invention according to (1) or (2), in the step of applying silicone oil to the surface of the toner layer using a heat fixing roller, the temperature of the silicone oil is controlled by the heat fixing roller. It is controlled by the heating temperature of

The viscosity and surface tension of the silicone oil change with temperature. When the silicone oil adheres, the viscosity is 0.1 poise or more and the surface tension is 1
Since it is necessary to be 5.0 dyn / cm or less, it is easiest to control the viscosity and the surface tension of the silicone oil by controlling the heating temperature of the heat fixing roller which is originally heating.

(4) Further, the present invention provides the above (1) to (4)
(3) In any one of the above, the refractive index of the silicone oil
n_sIs the refractive index n of the resin constituting the toner layer._bFor n
_s≧ n _bThe relationship is set.

Thus, the refractive index n _{s of} silicone oil
With respect to the refractive index n _{b of the} resin constituting the toner layer, n _s ≧
By setting the relationship of n _b , the specular reflection on the toner layer surface can be increased, and
The effect of increasing the gloss can be further enhanced. In this case, it is desirable that the silicone oil be colorless and transparent, so that only the glossiness can be increased without deteriorating the quality of the fixed image.

(5) Further, according to the present invention, in a multicolor image forming apparatus having a process of fixing a plurality of toner layers as images on a recording medium, the plurality of toner layers are fixed as images on the recording medium. It is characterized in that a silicone oil supply means for constantly supplying silicone oil to the surface of the heat roller constituting the heat fixing roller is provided.

As described above, in order to adhere the silicone oil to the surface of the toner layer, it is desirable to provide a silicone oil supply means for constantly supplying the silicone oil to the surface of the heat roller constituting the heat fixing roller. By attaching the silicone oil with the roller, it is possible to print an image having appropriate gloss and less gloss unevenness.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, a preferred procedure of an embodiment of the present invention will be described. In the embodiment of the present invention,
First, as a recording medium, a color office W (Fujitsu P
& S product name), image size 10cm × 10cm
Then, using a print sample in which a magenta image having a density of 100% was fixed at 180 ° C. with a toner adhesion amount of 0.7 mg / cm ² , a silicone having the following chemical formula was applied to this print sample using a heat fixing roller. The oil was applied under various conditions and applied at a paper feed speed of 30 mm / sec to obtain an evaluation sample.

[0020]

Embedded image In this case, specific examples of the silicone oil used in the present invention, substituent R is, -CH _3, -OH, -COOH, -
_{CH 2 CH 2 CH 2 (CF} 2) N CF 3, carbon containing chlorophenyl group, a long-chain alkyl groups, silicone oil is a trifluoromethyl group, or silicon functional form and the functional group is bonded to Si, an organic group The modified silicone oil is in a functional form, but is not limited thereto. What is important is the viscosity and surface tension of the silicone oil at the time of adhesion.

It should be noted that the printing sun before applying the silicone oil
Average surface roughness R of the image in pull _aIs 0.99 μm
Met. When measuring the surface roughness of this image, the surface
Shape measuring microscope VF-7500 (a product made by Keyence Corporation)
) At a sampling pitch of 0.52 μm and
The area of 27 mm was measured 20 times at different positions,
Average value is average surface roughness R_aAnd

Next, referring to FIG. 2, a description will be given of a silicone oil application device used in the embodiment of the present invention. FIG. 2 is a conceptual configuration diagram of a silicone oil application device used in the embodiment of the present invention. In the embodiment of the present invention, silicone oil is applied using a heat fixing roller. . In this case, the heat roller 11 and the pressure roller 14, which constitute the heat fixing roller, are formed by applying fluororesin coats 12, 15 to the surface of an aluminum hollow cylinder, and the contact length (nip) is about 5 mm. The heat roller 11 contains a halogen lamp 13 serving as a heating source.

The silicone oil is supplied to the heat roller 11
The silicone oil supplied from the silicone oil supply roller 17 is constantly supplied to the fluororesin coat 12 on the surface of the heat roller 11 from the silicone oil supply roller 17 in contact with the heat roller 11. The printed sample on which the image is formed, that is, the recording medium 18 is applied.

A temperature sensor 16 is provided on the heat roller 11 side to measure the surface temperature thereof.
The heating amount of the halogen lamp 13 is controlled by the temperature sensor 16, thereby controlling the viscosity and the surface tension of the silicone oil. In the embodiment of the present invention, the viscosity of 0.1 poise or more, .0 dy
The temperature is controlled so that the surface tension becomes n / cm or less.

When the silicone oil adheres to the surface of the image in the fixing process, not after the fixing,
It is necessary to control the temperature so as to have a viscosity of 0.1 poise or more and a surface tension of 15.0 dyn / cm or less. In this case, fixing by heat is performed at the same time.
The temperature of 1 needs to be controlled at 70 to 250 ° C.

In this case, the viscosity of the silicone oil was measured using a rheometer ARES (trade name, manufactured by Rheometrics Co., Ltd.). The viscosity at the time of was determined. The surface tension of the silicone oil was measured using a surface tension meter ESB-V (trade name, manufactured by Kyowa Kagaku Co., Ltd.), and the surface tension was determined at the temperature set at the actual application.

Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. Before that, a method of evaluating the glossiness of an evaluation sample coated with silicone oil will be described. The specular gloss (gross) of the image was measured using a gloss meter Multi-Gloss 268 (trade name, manufactured by Minolta) at an incident angle of light of 60 ° with respect to the image.

The evaluation method of the image is as follows. When the glossiness of the printed sample before application of the silicone oil is increased by 5% or more from the glossiness of 18.8 before the application of the silicone oil, the evaluation is evaluated as ○. 0.5% or more
Less than 0.5 was evaluated as x.

Based on the above, Examples 1 to 6 and Comparative Examples 1 to 6 will be described. (Example 1) Using Oil 1 as a silicone oil,
The surface temperature of the heat roller 11 is 160 ° C., the viscosity of the oil 1 is 0.33 poise, and the surface tension is 14.5 dyn /
In cm, Oil 1 was applied to the surface of the above-mentioned print sample to obtain an evaluation sample. The glossiness after application of the silicone oil in Example 1 was 22.6, which was about 20.2% higher than before the application, and was evaluated as ○.

Example 2 The same oil 1 was used as the silicone oil, and the surface temperature of the heat roller 11 was set to 180 ° C.
The viscosity of the oil 1 was set to 0.29 poise, the surface tension was set to 13.7 dyn / cm, and the oil 1 was applied to the surface of the above printed sample to obtain an evaluation sample. The gloss after silicone oil application in Example 2 was 2
In the case of 2.2, since it was improved by about 18.1% compared to before coating, it was evaluated as ○.

Example 3 Oil 2 was used as the silicone oil, and the surface temperature of the heat roller 11 was set to 160 ° C.
Oil 2 has a viscosity of 0.12 poise and a surface tension of 1
At a rate of 3.7 dyn / cm, oil 2 was applied to the surface of the above printed sample to obtain an evaluation sample. The gloss after silicone oil application in Example 3 was 21.0.
The result was about 11.7% higher than before the application, and was evaluated as ○.

Example 4 The same oil 2 was used as the silicone oil, and the surface temperature of the heat roller 11 was set to 180 ° C.
The viscosity of oil 1 was 0.11 poise, the surface tension was 12.9 dyn / cm, and oil 2 was applied to the surface of the above printed sample to obtain an evaluation sample. The gloss after silicone oil application in Example 4 was 2
The value of 0.7 was improved by about 10.1% from that before the application, and was evaluated as ○.

Example 5 The oil 3 was used as the silicone oil, the surface temperature of the heat roller 11 was set to 160 ° C.
Oil 3 has a viscosity of 0.14 poise and a surface tension of 1
An oil 3 was applied to the surface of the above printed sample at 2.7 dyn / cm to obtain an evaluation sample. The gloss after silicone oil application in Example 5 was 20.9.
The result was about 11.2% higher than that before the application, and was evaluated as ○.

Example 6 The same oil 3 was used as the silicone oil, and the surface temperature of the heat roller 11 was set to 180 ° C.
Oil 3 was applied to the surface of the above-mentioned print sample, and the viscosity of Oil 1 was set to 0.11 poise and the surface tension was set to 13.7 dyn / cm. The glossiness after silicone oil application in Example 6 was 2
The value of 0.7 was improved by about 10.1% from that before the application, and was evaluated as ○.

Comparative Example 1 A print sample on which an image was fixed without applying silicone oil was again passed through a heat roller 11 having a surface temperature of 180 ° C. to obtain an evaluation sample. The glossiness after passing through the heat roller in Comparative Example 1 was 18.8, and there was no change from that before passing.
Was evaluated.

Comparative Example 2 The same oil 1 as in Examples 1 and 2 was used as the silicone oil, and the heat roller 11 was used.
The surface temperature of 25 ° C., the viscosity of Oil 1 was 0.53 poise, and the surface tension was 22.4 dyn / cm. Oil 1 was applied to the surface of the above printed sample to obtain an evaluation sample. The glossiness after application of the silicone oil in Comparative Example 2 was 18.8, which was not changed at all from that before the application, and was evaluated as x.

Comparative Example 3 The same oil 1 as in Examples 1 and 2 was used as the silicone oil.
And the viscosity of Oil 1 was 0.16.
Poise, surface tension is 15.7 dyn / cm,
Oil 1 was applied to the surface of the above printed sample to obtain an evaluation sample. The glossiness after application of the silicone oil in Comparative Example 3 was 18.8, which was not changed at all from that before the application.

Comparative Example 4 The same oil 2 as in Examples 3 and 4 was used as the silicone oil, and the heat roller 11 was used.
The surface temperature of the oil 2 was 100 ° C.
Poise, surface tension of 16.5 dyn / cm,
Oil 2 was applied to the surface of the above printed sample to obtain an evaluation sample. The glossiness after application of the silicone oil in Comparative Example 4 was 18.9, which was about 0.53% of that before the application.
Since it only improved, it was evaluated as △.

Comparative Example 5 The same oil 3 as in Examples 5 and 6 was used as the silicone oil, and the heat roller 11 was used.
The surface temperature of the oil 3 is set to 120 ° C. and the viscosity of the oil 3 is set to 0.14.
Poise, surface tension is 17.2 dyn / cm,
Oil 3 was applied to the surface of the above printed sample to obtain an evaluation sample. The glossiness after application of the silicone oil in Comparative Example 5 was 19.1, which was about 1.6% higher than before the application.
Since it only improved, it was evaluated as △.

Comparative Example 6 Oil 4 was used as the silicone oil, and the surface temperature of the heat roller 11 was set to 160 ° C.
Oil 4 has a viscosity of 0.093 poise and a surface tension of 1
An oil 4 was applied to the surface of the above printed sample at 4.9 dyn / cm to obtain an evaluation sample. The glossiness after silicone oil application in Comparative Example 6 was 18.8.
And there was no change from before the application, so it was evaluated as x.

FIG. 1 is a correlation diagram between surface tension and viscosity in Examples 1 to 6 and Comparative Examples 1 to 6. Examples in which favorable results were obtained are indicated by black diamonds. Comparative examples in which a high degree of gloss was not obtained are indicated by black squares. As is clear from the drawing, the boundary separating the example and the comparative example has a viscosity of 0.1 poise and a surface tension of 15.0 dyn / cm. Therefore, it is understood that in order to obtain an appropriate gloss, the viscosity of the silicone oil at the time of application should be 0.1 poise or more and the surface tension should be 15.0 dyn / cm or less.

FIG. 3 summarizes the evaluation of the glossiness in Examples 1 to 6 and Comparative Examples 1 to 6. FIG. 3 shows the boundary conditions where an appropriate glossiness cannot be obtained as shown in FIG. The cause is shaded. As is clear from the figure, Examples 1 and 2 and Comparative Examples 2 and 3
Even if you use the same silicone oil,
It is understood that if the surface temperature of the heat roller at the time of application is different, the viscosity and the surface tension are different, thereby obtaining different results. In Comparative Examples 2 and 3, the temperature of the heat roller is too low and the surface tension is large. It is considered that the cause is too much. It is understood from the comparison between Example 1 and Example 2 that the surface tension can be reduced by increasing the temperature of the heat roller.

The same applies to Comparative Examples 4 and 5, where the surface temperature of the heat roller is low.
Although the same silicone oil as in Example 4 and Example 5 was used, it is considered that the reason was that the surface tension was too large.

On the other hand, in the case of Comparative Example 6, although the temperature of the heat roller was set to 160 ° C. as in Examples 1, 3, and 5, the viscosity was too low at 0.093 poise. It is considered that a high glossiness cannot be obtained. In order to increase the viscosity, the temperature of the heat roller may be lowered, but then, 14.9 dyn / 160 ° C.
cm, the surface tension increases to 15.0 dyn / c.
m or less.

Comprehensively judging the results, it is understood that it is not the specific components of the silicone oil that determine the appropriateness of the glossiness but the viscosity and surface tension at the time of application are important. If it is smaller than 1 poise, it is considered that the glossiness does not increase because the amount of the silicone oil transferred to the fixed toner layer surface decreases,
On the other hand, if the surface tension is larger than 15.0 dyn / cm, it is considered that the glossiness does not increase because the silicone oil does not penetrate into the gap formed in the fixed toner layer.

Although the embodiments and examples of the present invention have been described above, the present invention is not limited to the configurations and conditions described in the above embodiments and examples, and various changes may be made. It is possible. For example, in each of the above-described embodiments, the print sample on which the image has been fixed at one end is passed through the heat fixing roller supplied with silicone oil. However, the present invention is not limited to the image after fixing, and the fixing of the toner layer is not limited. And the application of silicone oil may be performed simultaneously.

In each of the embodiments of the present invention, a single silicone oil is used, but two or more kinds of silicone oils may be used in combination.
In any case, the viscosity at the time of application is 0.1 poise or more,
In addition, the surface tension may be 15.0 dyn / cm or less.

In each of the embodiments of the present invention, the refractive index n _s of the silicone oil is not specifically mentioned, but the refractive index n _{b of the} resin constituting the toner layer fixed on the recording medium is not described. Therefore, it is desirable to satisfy the relationship of n _s ≧ n _b , and by setting in this manner, more excellent gloss can be obtained. Naturally, it is desirable that the silicone oil be colorless and transparent.

In the embodiment of the present invention, the silicone oil supply roller is used as a means for supplying the silicone oil to the heat roller. However, the roller is not necessarily required to be in the form of a roller. It is also possible to use silicone oil in a silicon-like material.

In the embodiment of the present invention, the silicone oil is applied by using the heat fixing roller. However, it is not always necessary to use the heat fixing roller, and the heat roller is provided separately from the heat fixing roller. May be used to apply silicone oil.

In the embodiment of the present invention, a heat fixing roller is used as an image fixing means for a print sample. However, the heat fixing roller is not necessarily required. Alternatively, another fixing method such as an oven fixing method may be used.

[0052]

According to the present invention, the silicone oil having a viscosity of 0.1 poise or more and a surface tension of 15.0 dyn / cm or less is applied to the image after fixing or in the fixing process at the time of coating. , The glossiness can be improved by reducing the average surface roughness, thereby obtaining a high-quality multicolor image having an appropriate glossiness. The contribution is great.

[Brief description of the drawings]

FIG. 1 is a correlation diagram between surface tension and viscosity in each example.

FIG. 2 is a conceptual configuration diagram of a silicone oil application device used in the embodiment of the present invention.

FIG. 3 is an explanatory diagram of evaluation results of an image to which silicone oil has been applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Heat roller 12 Fluororesin coat 13 Halogen lamp 14 Pressure roller 15 Fluororesin coat 16 Temperature sensor 17 Silicone oil supply roller 18 Recording medium

Claims (5)

[Claims] 1. A multicolor image forming method comprising a step of fixing a plurality of toner layers as images on a recording medium,
Multicolor image formation characterized in that a silicone oil whose temperature is controlled so that the viscosity is 0.1 poise or more and the surface tension is 15.0 dyn / cm or less is adhered to the surface of the fixed toner layer. Method. 2. A multicolor image forming method, comprising: fixing a plurality of toner layers as images on a recording medium.
A multicolor, characterized in that a silicone oil whose temperature is controlled so that the viscosity is 0.1 poise or more and the surface tension is 15.0 dyn / cm or less is adhered to the surface of the toner layer during the fixing process. Image forming method. 3. The method according to claim 1, wherein in the step of applying silicone oil to the surface of the toner layer using a heat fixing roller, the temperature of the silicone oil is controlled by the heating temperature of the heat fixing roller. Or the multicolor image forming method according to 2. 4. The refractive index n _s of the silicone oil is set to be n _s ≧ g with respect to the refractive index n _{b of the} resin constituting the toner layer.
claims 1 to 3, characterized in that to set the relationship of n _b
The multicolor image forming method according to any one of the above items. 5. A multicolor image forming apparatus having a process of fixing a plurality of toner layers as images on a recording medium,
A multicolor image forming apparatus, wherein a silicone oil supply means for constantly supplying silicone oil to a surface of a heat roller constituting a heat fixing roller for fixing the plurality of toner layers as images on a recording medium is provided.