JPH0375772A - Toner fixing device - Google Patents

Abstract

PURPOSE:To raise fixing strength and to make picture quality into high grade by permitting a high-temperature heat roller to comprehensively fixing toner on a recording sheet at a high temperature after a low-temperature heat roller temporarily fixes the toner a low temperature. CONSTITUTION:After the toner 2 supplied to a photosensitive drum 10 is transferred onto the recording sheet 1, a conveying belt 12 leads the sheet to the low-temperature heat roller 3 to temporarily fix the toner 2 transferred onto the recording sheet 1 at a low temperature. A feed roller 13a leads the temporarily fixed recording sheet 1 to the high-temperature heat roller 4, and the toner 2 temporarily fixed at a high temperature is comprehensively fixed to the recording sheet 1. After that, the recording sheet 1 is ejected through a feed roller 13b behind a roller 4. Then, the toner 2 is sufficiently fixed to the recording sheet 1 without adversely affecting various picture quality conditions such as line picture quality and picture density. Thus, a picture with high fixing strength and high grade picture quality can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a toner fixing device for fixing toner transferred onto recording paper in an electrophotographic apparatus or the like.

[Prior art and its problems] Conventionally, in electrophotographic devices and the like, it has been difficult to transfer toner from a photoreceptor drum or the like onto recording paper and then fix the toner thus transferred onto the recording paper. It was done.

Here, in order to fix the toner transferred onto the recording paper as described above, generally, the recording paper with the toner transferred thereto is guided between heating rollers, and the toner on the recording paper is fixed by this heating roller. It used heat and pressure to fix it on the recording paper.

However, various image quality conditions such as the fixing strength of the toner fixed on the recording paper and the line image quality of the fixed toner image and the two-image test temperature change depending on the fixing conditions such as the fixing temperature and fixing speed of the heating roller. However, it has been difficult to fix a toner that fully satisfies both toner fixing strength and various image quality conditions.

That is, when the temperature of the heating roller is increased,
The fixing strength of the toner improves, but if you fix the toner at such high temperatures from the beginning, the toner will rapidly melt and spread, resulting in crushed line images, deterioration of the quality of the toner, and loss of gloss, resulting in insufficient density. There was a problem in that the image quality was adversely affected, such as the inability to obtain images.

On the other hand, when the temperature of the heating roller is lowered, a somewhat satisfactory image quality can be obtained without the above-mentioned collapse of the line image or deterioration of the quality of the toner, but the fixing strength of the toner to the recording paper is weak. This causes problems such as the toner becoming easily separated from the recording paper.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned problems in a toner fixing device that fixes toner transferred onto recording paper.

That is, in this invention, when fixing the toner transferred onto the recording paper as described above, the toner is sufficiently applied to the transfer paper without adversely affecting various image qualities such as line image quality and image density. The challenge is to make it take root in Japan.

[Means and effects for solving the problem] In order to solve the above-mentioned problems, the toner fixing device according to the present invention includes a low-temperature heating roller that temporarily attaches the toner transferred onto the recording paper to the recording paper at a low temperature. In addition, a high-temperature heating roller is provided which causes the toner tentatively deposited on the recording paper by the low-temperature heating roller to be permanently fixed on the recording paper at a high temperature.

In the toner fixing device configured in this way, first, the toner transferred onto the recording paper is temporarily attached to the recording paper using a low-temperature heating roller, and then the toner temporarily attached in this way is transferred to the recording paper using a high-temperature heating roller. The book is set to become established.

Therefore, compared to the case where the toner is fixed to the recording paper in one step, the toner can be sufficiently fixed to the recording paper with lower fixing conditions, and the line image that occurs when the toner is fixed at high temperature from the beginning This eliminates smearing and toner deterioration, and there is no adverse effect on various image quality conditions such as line image quality and image density, making it possible to obtain high-quality images.

Note that when temporarily depositing the toner on the recording paper using the low-temperature heating roller, it is preferable to perform the temporary deposition of the toner at a high speed in order to further improve the quality of the formed image.

On the other hand, when the toner is permanently fixed on the recording paper by the high-temperature heating roller, it is preferable to perform this at a low speed so that the toner is sufficiently fixed on the recording paper.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings.

In this embodiment, as shown in FIG. 1, the toner (2) supplied to the photosensitive drum (10) is transferred onto the recording paper (1) via a charger for transfer/separation (11). After the transfer, the recording paper (1) is guided between low-temperature heating rollers (3), (3) by a conveying belt (12).

In this example, the conditions for fixing the toner (2) on the low-temperature heating rollers (3), (3) are set such that the fixing temperature is 150°C and the fixing speed is 500 mm/s. , the toner (2) transferred onto the recording paper (1) as described above is transferred to the low-temperature heating rollers (3), (3).
) is assumed to be worn between.

After the toner (2) is temporarily attached to the recording paper <1> between the low-temperature heating rollers (3) and (3) in this way, this recording paper (1) is sent to the rollers (13a) and (13a). ) between the high-temperature heating rollers (4), (4).

Here, as the conditions for fixing the toner (2) by the high temperature heating rollers (4), (4), in this example, the fixing temperature is 240'C, and the fixing speed is 50 gua/
s, and the toner (2) tentatively attached as described above is permanently fixed on the recording paper (1).

After the toner (2) is permanently fixed on the recording paper (1) between the high-temperature heating rollers (4) and (4) in this way, the recording paper (1>) is transferred to the high-temperature heating roller (4).

Feed roller (13b) located behind (4>), (1
3b).

In addition, in order to compare with that of this example, in comparative example 1, the toner (2
> and the above low temperature heating roller (3).

(3) Directly fixes at a temperature of 240 without pre-fixing.
The recording paper (1
) The toner (2) transferred onto the surface was fixed.

In addition, in Comparative Example 2, the toner (2) transferred onto the recording paper (1) was fixed by the low-temperature heating roller (3) set to the fixing conditions of a fixing temperature of 150° C. and a fixing speed of 550 mm/s. , (3) alone to fix the image on the recording paper (1).

Furthermore, in Comparative Example 3, the toner (2) transferred onto the recording paper (1) was first heated at a fixing temperature of 240°C.
After fixing on the recording paper (1) with the high temperature heating rollers (4), (4) set to a fixing condition of a fixing speed of 50 mm/s, this is further fixed at a fixing temperature of 150° C. and a fixing speed of 550 mm/s.
The fixing was carried out using the low temperature heating rollers (3) and (3) set to the fixing conditions of III/S, and then the fixing was carried out on the recording paper (1) by the above Examples and Comparative Examples 1 to 3. The state of the toner (2) was compared.

As a result, in Comparative Example 1.3, recording paper (1
), the fixing strength of toner (2) was high, but the image quality was unsatisfactory as there were collapses in the line image, density changes and background fogging due to deterioration of toner (2).

In addition, in Comparative Example 2, there were no problems in terms of image quality such as line image blurring, image density, background fogging, etc., but the fixing strength of toner (2) to recording paper (1) was weak. , the toner (2) was easily detached from the recording paper (1).

On the other hand, in the above example, there is no problem in terms of image quality such as line image collapse, image density, background blurring, etc., and the fixing strength of the toner (2) to the recording paper (1) is also high. The toner (2) did not come off from the recording paper (1).

[Effects of the Invention] As detailed above, in the toner fixing device according to the present invention, the toner transferred onto the recording paper is temporarily deposited on the recording paper using a low-temperature heating roller, and then the toner is temporarily deposited in this way. Because the toner is permanently fixed on the recording paper using a high-temperature heating roller, there are no problems such as line image collapse and toner deterioration that would occur if the toner transferred onto the recording paper was fixed to the recording paper using only a high-temperature heating roller. Furthermore, the fixing strength of the toner is weak and the toner does not peel off from the recording paper, which is the case when the toner is fixed to the recording paper using only a low-temperature heating roller.

As a result, when the toner fixing device according to the present invention is used, there is no adverse effect on various image quality conditions such as line image quality and image density, and the toner transferred onto the recording paper is sufficiently fixed on the recording paper. It has become possible to obtain images with high fixing strength and high quality.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing a toner fixing device according to an embodiment of the present invention, in which a recording paper on which toner has been transferred is guided between low-temperature heating rollers and temporarily attached, and FIG. FIG. 2 is a schematic side view showing a state in which a recording paper on which toner is temporarily attached by a low-temperature heating roller is guided to a high-temperature heating roller and permanently fixed in the toner fixing device.

Claims (1)

[Claims] 1. A low-temperature heating roller that temporarily fixes the toner transferred onto the recording paper to the recording paper at a low temperature, and a high-temperature heating roller that permanently fixes the toner temporarily attached to the recording paper by the low-temperature heating roller to the recording paper at a high temperature. A toner fixing device comprising: