KR100597243B1 - Fusing unit for image forming apparatus - Google Patents

Abstract

Disclosed is a fixing apparatus of an image forming apparatus for fixing a visible image by a toner transferred onto a printing paper to heat and pressure to fix the printing paper. The fixing apparatus according to the present invention includes a plurality of sets of fixing roller units having a pair of heating rollers and pressure rollers which are pressed against each other, and each fixing roller unit is characterized in that the printing paper is divided into sections for fixing. An example is provided in which two sets of first and second fixing roller units are arranged at a predetermined interval on a straight line of printing paper, and in this case, the first fixing roller unit includes a first fixing unit for fixing both sections of printing paper. The second fixing roller unit includes a second fixing unit for fixing the center section of the printing paper. The deformation of the paper in the fixing process according to the present invention can be prevented, the paper wrinkle phenomenon can be minimized, and the warm-up time of the fixing roller unit can be reduced.

Fusing, Roller, Pressurized, Pressure, Heating, Heating, Double, Multi, Multi, Printer

Description

FUSING UNIT FOR IMAGE FORMING APPARATUS}

1 is a perspective view schematically showing a fixing apparatus of a general image forming apparatus;

FIG. 2 is a view illustrating a rear end of the printing paper generated during the fixing process using the fixing apparatus of FIG. 1;

3 is a perspective view schematically showing another example of a general fixing device;

4 is a perspective view schematically showing a fixing device of an image forming apparatus according to an embodiment of the present invention;

5 is a side view of FIG. 4, and

6 is a front view of FIG. 4.

<Description of Symbols for Main Parts of Drawings>

100,200; first and second fixing roller unit

110,210; Heating roller 120; 220; Pressure roller

111,121,211,221; shaft 112,122,212,222; first and second fixing unit

P; Printing paper D; Nesting section

The present invention relates to an image forming apparatus, and more particularly, to a fixing apparatus for fixing an image to a printing sheet by applying heat and pressure to the printing sheet onto which the image is transferred.

As is well known, electrophotographic image forming apparatuses such as printers, copiers, plain paper facsimile machines, etc., are applied to a printing paper by applying heat and pressure to a fixing device including a heating roller and a pressure roller. Fix and print.

1 is a view schematically showing an example of such a fixing device. As shown, the fixing device of the image forming apparatus includes a heating roller 1 and a pressure roller 2 which are pressed against each other. As shown in Fig. 2, the printing paper P is passed through between the heating roller 1 and the pressure roller 2, and at this time, a visible image by the toner transferred to the printing paper P is predetermined. It is fixed to the printing paper P by receiving heat and pressure.

In order to improve fixability, it is preferable to increase the pressing force between the heating roller 1 and the pressing roller 2, but when the pressing force is increased, wrinkles occur on the printing paper.

In order to prevent wrinkling, a fixing device is known in which a heating roller 1 is formed in an inverse crown shape so that the speed of both ends of the heating roller 1 is faster than the speed of the central part so as to straighten the printing paper before entering the heating roller. have.

However, in the fixing apparatus having the heating roller of the reverse crown shape as described above, as shown in Figure 2, the printing paper (P) passing between the heating roller 1 and the pressure roller (2) difference in ship speed There is a problem that an image scratch occurs when the end of the printing paper P is lifted while deforming. In other words, the visible image of the toner before passing through the heating roller is not yet fixed on the printing paper, and thus it is easy to cause an image scratch even when very weak contact with other apparatus occurs. By lifting together, an image scratch phenomenon occurs in contact with another mechanism 3 such as a toner cartridge.

In addition, although the wrinkle of the printing paper can be reduced to some extent by the reverse crown shape of the heating roller, the thin paper or the like does not completely solve the wrinkle. In addition, for example, in an image forming apparatus capable of printing A3-size paper, the length of the heating roller becomes long, which makes it difficult to process parts for maintaining the straightness in the case of a pressure roller.

As a countermeasure for this, as shown in FIG. 3, two pressure rollers 20 and 20 ′ are press-contacted to one heating roller 10, and the first pressure roller 20 covers both sides of the printing paper. In addition, a fixing device is known in which the second pressing roller 20 'is configured to divide and fix the central portion of the paper.

According to such a fixing device, the pressing force is small and the fixing failure such as wrinkles can be reduced, but it is difficult to reduce the size of the heating roller to a certain size or less, and the design constraints on the interval between the two pressure rollers are followed. There is a problem such as a lack of improvement.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object thereof is to provide a fixing apparatus for an image type growth value capable of preventing an image scratch or the like caused by the deformation of the paper by not deforming the paper during the fixing process.

Another object of the present invention is to provide a fixing apparatus of an image forming apparatus that can minimize paper wrinkles.

The fixing apparatus of the image forming apparatus according to the present invention for achieving the above object comprises a plurality of sets of fixing roller units, a pair of heating rollers and pressure rollers which are pressed against each other, wherein each fixing roller unit is a printing paper It is characterized in that settling by division.

According to a preferred embodiment of the present invention, two sets of first and second fixing roller units are arranged at regular intervals on a straight line of printing paper, and in this case, the first fixing roller unit is arranged at both sides of the printing paper. It comprises a first fixing unit for fixing, the second fixing roller unit is configured to include a second fixing unit for fixing the center section of the printing paper.

According to a more preferred embodiment, the fixing portions of the first and second fixing roller units are configured so that some of them are superimposed so that non-fixed image sections do not occur.

Further, the speed of the second fixing roller unit is set to be reduced by approximately 2 to 5% than the speed of the first fixing roller unit, whereby curl of paper is allowed between the two fixing roller units. Therefore, it is possible to prevent the paper slip or roll from pulling the papers together.

The objects, advantages and other features of the present invention will become more apparent by describing the preferred embodiments of the invention in detail with reference to the accompanying drawings.

4 is a perspective view schematically illustrating a fixing apparatus of an image forming apparatus according to an embodiment of the present invention, FIG. 5 is a side view of FIG. 4, and FIG. 6 is a front view of FIG. 4.

4 to 6, the fixing apparatus of the image forming apparatus according to the exemplary embodiment of the present invention includes two sets of fixing roller units 100 and 200. The first and second fixing roller units 100 and 200 are provided with a pair of heating rollers 110 and 210 and pressure rollers 120 and 220 which are pressed by a predetermined pressure, and on a straight line of the printing paper feed path. It is placed at regular intervals.

The first and second fixing roller units 100 and 200 as described above are configured to divide the printing paper P into several sections and to fix each section. To this end, the heating roller 110 and the pressure roller 120 of the first fixing roller unit 100 has a structure in which the first fixing parts 112 and 122 are disposed on both sides of the shafts 111 and 121. The heating roller 210 and the pressure roller 220 of the second fixing roller unit 200 have a structure in which second fixing units 212 and 222 are disposed at the centers of the shafts 211 and 221. .

That is, the predetermined sections on both sides of the printing paper P are first fixed by the first fixing roller unit 100, and then the central portion of the printing paper P is secondarily fixed by the second fixing roller unit 200. At this time, a part of the first and second fixing units 112, 122, 212, and 222 overlap each other so that the unfixed image section is not generated at the fixing unit boundary due to the divided fixing by the first and second fixing units. It is good to configure as possible. Of course, it is ideal to exactly match the boundary of the first and second fixing units, but since it is impossible in actual processing or assembly, it is preferable to provide the overlap section D in consideration of the predetermined tolerance as described above. The size of the overlapping section is not necessarily limited, and a range in which non-fixed image sections are generated may be sufficient. However, if the overlapping section is too large, the object of the present invention is difficult to achieve, which is not preferable.

In addition, the first and second fixing roller units 100 and 200 are set differently in their flux. For example, the speed of the second fixing roller unit 200 is reduced by about 2 to 5% from the speed of the first fixing roller unit 100 so that the curl of the paper between the two fixing roller units 100 and 200 is reduced. To allow.

If the paper curl is allowed between the two fixing roller units 100 and 200 in this way, the influence of the first fixing roller unit 100 does not reach the second fixing roller unit 200 so that the interaction between the fixing rollers, for example, In addition, it is possible to prevent the paper slip or the roller from pulling the paper together, thereby preventing the paper from being wrinkled. Of course, even in such a case, if the line speeds of the first and second fixing roller units 100 and 200 are exactly the same, there is no need to make a difference in line speed between the two rollers. However, as mentioned above, since rollers inevitably cause various errors due to the processing, assembly of the rollers, and environmental factors, it is preferable to provide a predetermined margin including the difference in the speed of the rollers as described above.

Hereinafter, a fixing process using the fixing device according to the present invention configured as described above will be described.

The printing paper P onto which the visible image by the predetermined toner is transferred enters the fixing apparatus. At this time, the fixing apparatus has already maintained a temperature at which it can be fixed through a warm-up operation or the like.

First, the printing paper P is a section passing between the first fixing units 112 and 122 of the first fixing roller unit 100, that is, a predetermined section on both sides of the printing paper P (at the length of the first fixing unit). The corresponding section) begins to settle.

Then, the printing paper P may be transferred to the second fixing units 212 and 222 of the first fixing roller unit 200 disposed at a predetermined distance to the downstream side of the first fixing units 112 and 122. As the middle section (section corresponding to the length of the second fixing unit) enters, the second settling begins.

That is, the printing paper is divided into several fixing sections and divided and fixed by each corresponding section. Therefore, the printing paper passing through the first fixing roller unit 100 does not press the center portion of the paper, so that the probability of wrinkles is reduced, compared to the structure that presses the front surface of the paper, and the line speed difference in the direction perpendicular to the paper feeding is Since it is reduced, the phenomenon that the back end of the paper is lifted can be reduced.

Meanwhile, in the illustrated example, the fixing apparatus including the first and second fixing roller units 100 and 200 is illustrated and described. However, the fixing apparatus of the present invention is also possible to have a configuration of three, four, five sets of fixing roller unit. In this case, it is a matter of course that the paper is divided into three, four, and five sections with predetermined widths from both sides thereof to be settled separately.

The present invention has been described in an exemplary manner. The terminology used herein is for the purpose of description and should not be regarded as limiting. Many modifications and variations of the present invention are possible in light of the above teachings. Accordingly, the invention may be freely practiced within the scope of the claims unless otherwise stated.

According to the present invention as described above, since the printing paper is divided into several sections and fixed for each section, the deformation of the paper can be prevented, and thus, the rear end of the paper on which the leading edge is fixed is lifted up, so as to The problem of damaging the image by contact can be prevented.

In addition, since the entire surface of the printing paper is not pressed, the deformation of the printing paper as well as the wrinkle phenomenon can be minimized.

In addition, since the length of the pressing roller or the like can be reduced, the machining of parts in terms of straightness and the like can be made easier.

In addition, it is possible to minimize the influence on the difference (difference between both sides and the center) of the fixing nip width that may occur in the roller structure having a conventional inverse crown shape.

In addition, the fixing area is divided so that the heating area of each heating roller is reduced, thereby reducing the warm-up time of the fixing roll.

Claims (5)

delete A fixing apparatus of an image forming apparatus for fixing a visible image by a toner transferred onto a printing sheet to heat the printing sheet by applying heat and pressure. It is arranged at a predetermined interval on the printing paper path, and includes two sets of first and second fixing roller unit which is a pair of heating rollers and pressure rollers which are pressed against each other, The first fixing roller unit includes a first fixing unit for fixing both sides of the printing paper, And the second fixing roller unit includes a second fixing unit for fixing the center section of the printing paper. The method of claim 2, And a portion of the first fixing unit and the second fixing unit overlapping each other so that an unfixed image section does not occur. The method of claim 2 or 3, A fixing apparatus of the image forming apparatus, characterized in that the curling speed of the second fixing roller unit is slowed down than that of the first fixing roller unit to allow curl of paper between the fixing roller units. The method of claim 4, wherein A fixing apparatus of an image forming apparatus, wherein a difference in line speed between two fixing roller units is about 2 to 5%.

Images