JPH0499623A - Image formation device - Google Patents

Abstract

PURPOSE:To prevent a recording medium from being poorly printed due to irregular ink application and ink run by printing the medium retained between a fixing roller with a specified surface hardness and a roller on which an ink image is formed. CONSTITUTION:A fixing roller 101, located at an opposite side to the printing surface of a recording medium 104, consists of a metal drum 102 and an elastic product 103 formed outside the roller. When the hardness of the fixing roller elastic product 103 is set to JIS-30 deg. or lower, the roller elastic product 103 becomes distorted and an image on the recording medium 10 becomes blurred, if a contact pressure with the fixing roller 101 is higher than a setting value. On the other hand, if the hardness of the fixing roller elastic product 103 is set to JIS-90 deg. or higher, the contact pressure tends to be offset easily between the fixing roller and an image forming medium, resulting in a variable image density on the recording medium 104. However, if the surface hardness of the fixing roller 101 is set to 30 to 100 JIS-A deg., preferably 35 to 90 JIS-A deg., neither of the mentioned defect modes occur and thereby a satisfactory image can be obtained.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an image forming method comprising a photoreversibly isomerizable substance that reversibly changes wettability by irradiating light of one or more wavelengths. The present invention relates to an image forming apparatus that performs exposure and development on an image forming body, selectively attaches ink to the surface of an image forming body, and transfers and attaches an ink image to a recording medium to form a printed matter.

[Prior Art] As an image forming apparatus, there is an optical printing method that performs exposure and writing. Specifically, an image forming body coated with a photoreversibly isomerizable substance is selectively exposed to light, an ink image is formed by taking advantage of the different wettability of ink, and the image is sandwiched between a fixing roller and a recording medium. Printing is performed by transferring the image onto the recording medium.

[Problem M to be Solved by the Invention] However, in the conventional apparatus described above, no consideration was given to the hardness of the fixing roller used.

For this reason, good printing quality may be obtained in some cases, but defective modes such as density unevenness and bleeding may occur, and the quality varies each time printing is performed. The present invention is intended to solve these problems, and its purpose is to provide an image forming apparatus that can stably produce high-quality printed matter by optimizing the hardness value of the surface of the fixing roller. It is in a place where we provide.

[Means for Solving the Problems] The image forming apparatus of the present invention forms a latent image by selectively exposing an image forming member having a photoreversibly isomerizable layer to change the wettability of the surface, and ink. In an image forming apparatus that forms a printed matter by transferring an image formed by adhering to the latent image onto the recording medium, the surface hardness of the fixing roller is determined according to JIS
- In measurement according to -6301, 30 to 100 J
[Function] According to the above structure of the present invention, the surface hardness is JIS-6.
30-100 JIS-A in measurement according to 301
By performing sandwich printing between the fixing roller set at a temperature of 35 to 90 JIS-A degrees and the roller on which an ink image is formed, printing defects such as ink unevenness and bleeding on the recording medium can be avoided. First, it becomes possible to obtain stable high-quality printed matter as a result [Embodiment] FIG. 1 shows an embodiment of an image forming apparatus according to the present invention.

The fixing roller (101) referred to in the present invention is the recording medium (10
4) It is located on the opposite side of the printing surface and is set to ensure good ink fixation during printing. The fixing roller includes a metal drum (102) and an elastic body (
103).

An example of how ink transfer is performed is as follows.

That is, the image forming body (106) formed by applying the photoreversibly isomerizable layer (105) to the base material is basically cylindrical, and has the shape of an arrow (10).
It is rotationally driven in the direction of 7). Now, by selectively exposing (108) onto the image forming body, it is possible to bring about a change in wetting on the surface of the photoreversibly isomerizable substance. Thereafter, by applying ink (109) to the surface of the grain formation, a negative or positive latent image can be formed.

The ink on the latent image is transferred to the transfer roller as the image forming body rotates, and the recording medium is sandwiched between the transfer roller and the fixing roller and is printed by applying the contact pressure generated between the two rollers.

The fixing roller used in the present invention is not particularly limited as long as it is cylindrical. For example, as shown in Figure 1, a metal drum with an elastic body attached to it, or as shown in Figure 2 (201), a rod-shaped substance made of a material that is resistant to warping and an elastic body attached to it are relatively preferred. .

Of course, the thickness, diameter, etc. of the drum, rod, elastic body, etc. may be designed as appropriate.

According to the evaluation of the image system composite shown in FIG. 1, the hardness of the surface of the fixing roller was 30 to 100 JIS-A degrees, preferably 35 to 9 degrees, when measured according to JIS-6301.
It was found that 0 JIS-A degree is an appropriate value.

In order to print a clear image on a recording medium, the ink image formed on the surface of the ink image forming body is first transferred to a transfer roller.
Subsequently, accurate transfer onto the recording medium is a necessary condition. In the image recording apparatus shown in FIG. 1, when the hardness of the fixing roller elastic body (103) is set to less than JIS-30 degrees, when the contact pressure with the fixing roller (101) becomes greater than the setting, the roller elastic body causing distortion of the body (103),
As a result, the image on the recording medium becomes blurred.According to the evaluation results, it was found that a slight parallel misalignment between the fixing roller (101) and the image forming body (106) greatly changes the print quality. On the other hand, if the hardness of the elastic (103) body of the fixing roller is set to JIS-90 degrees or higher, contact pressure fluctuations are likely to occur between the fixing roller and the image forming body, resulting in uneven image temperature on the recording medium. When the recording medium has ink absorbency, such as paper, ink smearing may occur in high contact pressure areas. However, the fixing roller (101
) If the surface hardness is set to 30 to 100 JIS-A degrees when measured in accordance with JIS-6301, the above-mentioned failure modes, such as image blur, temperature unevenness, and bleeding on the recording medium, will be eliminated. A good image was obtained without any of the following.

A more preferable value of hardness in the present invention is 35 to 65 degrees, but it was concluded that if the hardness is within the same range, higher speed printing is possible while maintaining sufficient image quality.

The developing device includes an ink supply device (110), an ink cartridge (111), and a developing roller.

In order to adjust the thickness of the ink, it is also preferably used to supply the ink to the surface of the image forming body via a plurality of rollers.

FIG. 2 shows the evaluation results of the embodiment according to the present invention.
Similar to the example shown in the figure, the surface of the fixing roller (201) was measured in accordance with JIS-6301.
By setting the A degree, preferably 35 to 90 JIS-A degree, ink transfer from the image forming body to the transfer roller can be clearly performed, and unevenness of ink on the recording medium can be prevented.
Printing defects such as blurring and blurring did not occur, and as a result, stable high-quality printed matter was obtained. Further, when the hardness was outside the above range, a failure mode similar to that of the example in FIG. 1 was observed, and good printing could not be obtained.

Further, FIGS. 3 and 4 show examples of the present invention, in which a transfer roller (314) is interposed between the fixing roller (101) and the image forming body (106). As a result of the evaluation, the JI on the surface of the fixing roller (101) was found to be similar to the example shown in FIG.
In measurement according to S-Ni-6301, 30 to 100
By setting the temperature to JIS-A degree, preferably 35 to 90 JIS-A degree, the transfer roller (314) is removed from the image forming body.
The ink transfer was now clearly carried out, and printing defects such as ink unevenness, blurring, and bleeding on the recording medium did not occur, and as a result, stable high-quality printed matter was obtained. Further, when the hardness was outside the above range, a failure mode similar to that shown in FIG. 1 was observed, and good printing could not be obtained. The photoreversibly isomerizable substance used in the present invention only needs to show a change in wettability to ink upon exposure, such as stilbenes that cause trans-cis isomerization, azobenzenes, and azohydrazones that cause keto-enol tautomerism. , fulgide series that cause ring-closing and opening reactions, spiropyran series that cause ring-opening reactions, triphenylmethane series that cause ion dissociation reactions, tetrabenzopentacene and dibenzo(a) that cause oxidation reactions.
, j) perylene-8,16 dione, etc. are used. Further, a method of dispersing the photoreversibly isomerizable substance in a polymer such as polyalkyl methacrylate, polystyrene, cellulose, polyvinyl butyral, polyester, polyethylene, phenoxy resin, polyurethane, etc. in order to form the photoreversibly isomerizable substance into a layer; Alternatively, a method in which the photoisomerizable substance appears on the surface, such as a method of bonding to the main chain or side chain of the polymer, or a method in which the photoisomerizable substance appears on the surface, such as a method in which the polymer is coated on the surface and then penetrated, or an appropriate combination of these methods. used.

Furthermore, in the present invention, various combinations of other transfer systems and photoreversible isomerizable substances were also investigated, but the correlation between the fixing roller surface hardness and printing quality was the same as the results of the example in FIG. It has been found that the present invention is effective regardless of the printing method.

[Effects of the Invention] As described above, according to the present invention, the fixing roller
In measurement according to JIS-6301, 30-1
By setting the surface hardness to 00 JIS-A degree, preferably 35 to 90 JIS-A degree, ink can be transferred from the image forming body to the transfer roller well, and as a result, defective modes such as printing blur, temperature unevenness, and bleeding can be prevented. This has the effect of obtaining good printed matter free of occurrence. Furthermore, the present invention has an effect that can be achieved regardless of the transfer system, and it is easy to print highly reliable images that are extremely stable despite fluctuations in transfer conditions such as temperature, humidity, and image forming body rotation speed. effective.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a diagram showing an embodiment of an image forming apparatus according to the present invention. FIG. 3 is a diagram showing an embodiment of an image forming apparatus according to the present invention. FIG. 4 is a diagram showing an embodiment of an image forming apparatus according to the present invention. 101... Fixing roller 103... Fixing roller elastic body 112... Ink cleaner latent image removal light fixing roller transfer roller

Claims (2)

[Claims] (1) A latent image is formed by selectively exposing an image forming body having a base material and a photoreversible isomerizable layer to change the wettability of the surface, and an image is created by adhering ink to the latent image. In the image forming apparatus that forms printed matter by transferring onto the recording medium, the surface hardness of the fixing roller is determined according to JIS-K-63.
1. An image forming apparatus characterized in that the temperature is 30 to 100 JIS-A degrees when measured in accordance with 01. (2) The surface hardness of the fixing roller is JIS-K-6301.
2. The image forming apparatus according to claim 1, wherein the image forming apparatus has a degree of 35 to 90 JIS-A when measured according to .