JPH0619357A - Fixing device and electrophotographic recorder - Google Patents

Abstract

PURPOSE:To remove offset toner without causing erroneous printing by resolving the particles of the offset toner which is recognized when a toner image is fixed on a recording paper to the offset toner which can not be recognized. CONSTITUTION:In the case an unfixed toner image formed on the recording paper is inserted to pass through fixing rollers 1 and 2, it passes so that an unfixed toner image carrying surface may come in contact with the heated fixing roller. In such a case, the brush 7 of a brush roller 3 is made of nylon fiber and the roller 3 is rotated by following the rotation of a heat roller(HR) 1, and the offset toner 6 is resolved. Therefore, the offset toner 6 is resolved on the surface of the HR 1 by following the rotation without being separated from the surface of the HR 1. Namely, by making the circumferential speed of the HR 1 coincide with that of the roller 3, the scraping effect of the offset toner 6 by the brush 7 of the roller 3 is prevented. Therefore, the offset toner is removed without causing the erroneous printing by using the recording paper 4 submitted for printing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording device using an electrophotographic system such as a printer, a copying machine and a facsimile,
In particular, the present invention relates to a fixing device for fixing a toner image formed on the surface of a recording body to the recording body.

[0002]

2. Description of the Related Art A conventional fixing device will be described below. The fixing device has at least a heat roller and a backup roller. In this specification, the heat roller may be abbreviated as HR and the backup roller may be abbreviated as BR for simplicity. Both the HR roller and the BR roller are called a fixing roller pair. Further, any one of HR and BR may be referred to as a fixing roller. HR is heated, HR and BR
Is pressed and rotates. By inserting the recording paper through this contact surface, the toner arranged as an image on the surface of the recording paper is fixed. Here, at least one of the fixing rollers may be heated. Further, when the toner image formed on the recording paper is inserted through the fixing roller, the toner image carrying surface and the heated fixing roller are inserted so as to come into contact with each other. In the fixing device, toner may adhere to the fixing roller when fixing the toner image. This development is called offset, and the toner attached to the fixing roller is called offset toner. When a large amount of the offset toner is generated, the offset toner is retransferred to the recording medium, which is indistinguishable from the recorded information and causes a problem of erroneous printing. FIG. 14 is a diagram showing the generation characteristics of the offset toner. Reference numeral 19 is a low temperature region, 20 is a high temperature region, and 21 is a non-offset band. The horizontal axis shows the temperature of the fixing roller, and the vertical axis shows the amount of offset toner. The amount of offset toner is large in the low temperature region 19 and the high temperature region 20, and
The offset that occurs in the low temperature offset, high temperature region 20
The offset that occurs in 1 is called a high temperature offset. The region narrowed between the low temperature region 19 and the high temperature region 20 is called a non-offset band 21, and the amount of offset toner is small.
In the fixing device, the temperature of at least one (mainly HR) of the fixing rollers is usually set in the non-offset band 21 in order to reduce the amount of offset toner as much as possible. Even if the temperature of the fixing roller is set in the non-offset band 21, a slight offset occurs. Therefore, during the period when the offset occurs, the fixing roller is contacted with a non-woven fabric or a porous substance to wipe the offset toner. There are fusing devices that have a cleaner to take. In this case, if it is attempted to collect an amount of offset toner that is larger than the amount by which the non-woven fabric or the porous substance can be collected, the offset toner once collected by the non-woven fabric or the porous substance is transferred to the fixing roller again.
Further, there is a problem that this is transferred to the recording body.
In order to prevent this, the cleaner made of the non-woven fabric or the porous material must be replaced before the offset toner wiped by the non-woven fabric or the porous material is accumulated to the above-mentioned amount that can be collected. Moreover, there is a problem that the exchange must be performed in a relatively short period.

In order to solve this problem, for example, Japanese Patent Publication No. 2
As described in JP-A-15072, a cleaner is used for the cleaner, and a release agent is applied to the brush to separate the offset toner collected and attached to the brush from the brush. It has been known. In this case, there is a problem that the offset toner separated from the brush stains the inside of the fixing device. Furthermore, in order to prevent this stain, there is also a problem that another device for collecting the offset toner separated from the brush is required.

Further, in order to reduce the amount of offset toner in the non-offset band 21, a releasing agent such as silicone oil may be applied to the fixing roller. In this case, there is a description that the amount of offset toner becomes zero by applying an appropriate amount of silicone oil to the fixing roller. However, the amount of offset toner is not limited to the amount of release agent, but is also supplied to the toner composition and additives, the thickness of the toner layer of the toner image deposited on the surface of the recording material, the print pattern and density, and the toner during fixing. The amount of offset toner becomes zero when the release agent is applied because it is defined in relation to various factors such as the amount of heat to be generated and the supply time thereof.
This is possible only under extremely limited conditions. Therefore,
Although it is possible to reduce the amount of offset toner by applying a release agent, it is often not zero. The present invention is premised on being applied when the amount of offset toner is not zero. In some cases, the cleaner and the release agent coating are used together. In this case also, since the offset does not become zero, the cleaner cannot collect the offset toner having a capacity higher than that of the cleaner, so the cleaner needs to be replaced. Compared to the case where the offset toner is removed only by the cleaner without applying the release agent as described above, the period until the cleaner is replaced is longer, but even if this method is used, it is still longer in the current technical situation. Is expected to grow. Therefore, even in this case, the problem that the period until the cleaner replacement is short remains. As another method for removing the offset toner, there is a case where the sheet-like cleaning member is passed between the pair of fixing rollers to remove the offset toner attached to the fixing roller to the cleaning member. As the cleaning member, a porous sheet or recording paper such as Japanese paper is used. However, in any case, the cleaning member is dedicated to cleaning, and the sheet used for cleaning is discarded not from the recording paper used for printing but from the beginning. That is, there is a problem that the operation of the recording apparatus is complicated. In order to eliminate this complexity, as described in JP-A-1-140181, there is also known a method of attaching offset toner to a recording paper used for printing and removing it. However, when there is a recognizable offset toner on the fixing roller, the offset toner is transferred to the recording paper used for printing as it is, which causes a problem that erroneous printing occurs on the recording paper having information. .

When the offset occurs, the problem is that the offset toner adhering to the fixing roller is retransferred to the recording paper to cause erroneous printing. Therefore, this problem cannot occur unless the offset toner retransferred to the recording paper is recognized as an image. The inventors confirmed the following phenomenon. The offset toner adhering to the fixing roller is a small particle that cannot be recognized at the beginning of printing. Some of these particles are re-transferred to the recording paper to be used for fixing next without being recognized and are discharged to the outside of the recording apparatus. However, some offset toner remains on the fixing roller without being retransferred immediately, and as the number of printed sheets increases, the remaining offset toners are combined with each other to grow into large particles, Eventually, the size becomes recognizable as an image. Some of these large particles are retransferred to the recording paper, which causes erroneous printing. When the fixing roller temperature is set to the low temperature region 19 or the high temperature region 20 shown in FIG. 14, the number of printed sheets until erroneous printing may occur on the second sheet. In addition, when it is set in the non-offset band 21, it becomes longer than when it is set in the high temperature or low temperature region.

As described above, the amount of offset toner in the non-offset band 21 should be small in any case, not limited to the case of the present invention. Also,
The present inventors have found that the HR drive source at the time of fixing, for example,
It has been found that the amount of offset toner increases or decreases depending on the degree of load variation of the HR drive motor. When the load change is significant, the clear non-offset band 21 may not be found. This load fluctuation is mainly caused by a rush impact at the front end of the recording paper when the recording paper is inserted through the contact surface formed between the HR and the BR, or a discharge impact at the rear end of the recording paper at the time of discharge.

Further, in the conventional fixing device, even if the recording medium continuously passes through the pressure contact surfaces of the HR and the BR, the temperature of at least one of the fixing rollers is controlled to be constant as described above. . Normally, the temperature of the HR that directly contacts the toner and melts the toner is controlled to be constant in the non-offset band 21. In the non-sheet passing state where the HR and the BR are in direct contact with each other, the temperature of the BR is as high as the HR temperature. This corresponds to a state before the sheet is passed in which the HR and the BR are in direct contact with each other and rotate. After the passage of the paper, the temperature of the BR not controlled may become significantly lower than the temperature of the controlled HR after the continuous passage of the recording medium to the pressure contact surface. In this state, in a fixing device having no cleaner for wiping off the offset toner, the offset toner transferred to the HR directly contacts the low temperature BR in the gap between the recording body and the next recording body, is cooled, and is fixed on the surface of the BR. To do. Then, the offset toner from the recording medium that is passed one after another is accumulated on the surface of the BR, causing a problem that the BR is soiled. Also, when the recording device is stopped with the offset toner adhered to the BR, and the printer is started next time, the B
When R is heated, the offset toner adhered to BR is melted, and the offset toner is re-transferred to the recording medium passing through the paper, which causes a serious problem that erroneous printing is caused.

[0008]

The problems of the prior art have been summarized above from the situation of countermeasures. As described above, the most preferable fixing roller cleaning method of the prior art is a method of removing the offset toner using the recording paper used for printing. However, even if this method is used, no consideration is given to the size of the offset toner transferred to the recording paper used for printing, and there is a problem that erroneous printing occurs.

Further, no consideration is given to load fluctuation of the HR drive source at the time of fixing, and there is a problem that a considerable amount of offset toner exists even in the non-offset band.

Further, no consideration has been given to the transfer of the offset toner to the BR, and there is a problem that erroneous printing occurs due to contamination of the BR or transfer of the offset toner from the BR to the recording medium at the time of restart. is there.

It is an object of the present invention to provide a good printing apparatus which removes offset toner existing on a fixing roller by using a recording paper used for printing, and is free from stains on BR and erroneous printing.

Another object of the present invention is to reduce the amount of offset toner in the non-offset band.

[0013]

According to the above-mentioned phenomenon, before the large particles of the offset toner are formed on the fixing roller, the particles are decomposed into small particles which are not recognized as an image. It has been found that erroneous printing can be prevented by removing the offset toner that has become large particles on the fixing roller. By disassembling the offset toner in this way, it is possible to remove the offset toner without causing erroneous printing on the recording paper used for printing, and when wiping large particles on the fixing roller. Since it is not necessary to wipe off all the particles, the amount of offset toner collected in the cleaner is significantly reduced, and the period until the cleaner replacement can be significantly extended.

Further, HR drive at the time of fixing due to a rush impact of the front end of the recording paper when inserting the recording paper into the contact surface formed between HR and BR, or a discharge impact of the rear end of the recording paper at the time of ejection. By reducing the degree of source load variation, the amount of offset toner in the non-offset band can be reduced. As a result, the reliability of preventing the occurrence of erroneous printing can be further enhanced, and when the offset toner is wiped off on the fixing roller, the period until the cleaner replacement can be significantly extended.

Further, the recording medium is brought into contact with the BR, and HR and B
It was found that the front end portion of the recording body wipes off the offset toner transferred to BR by passing the paper through the contact surface formed between R. As a result, the stain on the BR does not occur, and therefore erroneous printing due to the stain on the BR can be prevented.

According to the present invention, in order to prevent the occurrence of erroneous printing, the large particles are decomposed before they are formed on the fixing roller, and the large particles are so small that they cannot be recognized as an image. The particles are removed by attaching the small particles of the offset toner to the recording paper used for printing. When a cleaner is used, small unrecognizable offset toner particles are removed by adhering to the recording paper used for printing, and only large recognizable offset toner particles are collected by the cleaner. is there.

Further, according to the present invention, in order to reduce the amount of offset toner in the non-offset band, fixing is performed by a rush impact of the front end of the recording paper when the recording paper is inserted or a discharge impact of the rear end of the recording paper when the recording paper is discharged. The degree of load fluctuation of the HR drive source during time is reduced.

Further, according to the present invention, in order to prevent stains on the BR and erroneous printing due to the stains, the recording medium is brought into contact with the BR and the paper is passed through the contact surface formed between the HR and the BR. It is a thing.

[0019]

The offset toner decomposing device decomposes recognizable large offset toner particles formed on the fixing roller into small unrecognizable particles. As a result, even if the offset toner is present, it is not recognized, so that the offset toner can be removed by using the recording paper used for printing without causing erroneous printing.

Also, when a cleaner is used, the cleaner only collects large perceptible offset toner particles. As a result, the offset toner can be removed from the recording paper used for printing without causing erroneous printing.

Further, the load fluctuation reducing means of the HR drive source is
HR at the time of fixing due to a rushing impact of the front end of the recording paper when inserting the recording paper or a discharging impact of the rear end of the recording paper when discharging
The degree of load fluctuation of the drive source is reduced. Thereby, the amount of offset toner in the non-offset band can be reduced.

Further, the insertion guide member of the recording body that abuts the recording body against the BR and passes the paper through the contact surface formed between the HR and the BR wipes the offset toner transferred to the BR at the front end portion of the recording body. Acts like. Thereby,
The stain on the BR does not occur, and therefore erroneous printing due to the stain on the BR can be prevented.

[0023]

【Example】

<Embodiment 1> An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a sectional side view of a fixing device according to an embodiment of the present invention. 1 is a heat roller (HR), 2 is a backup roller (BR), 3 is a brush roller, 4 is recording paper, 5 is toner, 6 is offset toner, and 7 is a brush. HR1
Are heated, and HR1 and BR2 are pressed against each other to rotate. By inserting the recording paper 4 into this contact surface, the toner 5 arranged as an image on the surface of the recording paper 4 is fixed. here,
At least one of the fixing rollers may be heated.

Further, when the unfixed toner image formed on the recording paper is inserted through the fixing roller, it is inserted so that the bearing surface of the unfixed toner image and the heated fixing roller come into contact with each other. Further, when the fixing roller which is not fixed or the fixed toner image is inserted so as to come into contact with the heated fixing roller, when the fixed toner is carried on the heating surface, the unfixed toner is unfixed. Is carried, or the case where no toner is carried is included. The brush 7 of the brush roller 3 is made of nylon fiber, and the brush roller 3 is driven to rotate by the rotation of the HR 1 to decompose the offset toner 6.

The offset rotation causes the HR of the offset toner to be HR.
It can be degraded at the HR1 surface without separation from the 1 surface. That is, it means that the scraping effect of the offset toner by the brush 7 of the brush roller 3 is prevented by making the peripheral speeds of the HR 1 and the brush roller 3 substantially equal to each other. As a result, the offset toner can be removed using the recording paper 4 to be printed without causing erroneous printing. <Embodiment 2> The structure of this embodiment is the same as that of FIG. HR1 is heated and its set temperature is 180 ° C., which temperature is in the non-offset band 21 shown in FIG. According to the experiments conducted by the inventors, when HR1 having no offset toner 6 is used and one page of A4 size paper is fixed without contacting the brush roller 3 with HR1, it is 2 mm.
Average of about eight toner by the offset in the ^2, HR1
Transferred to. At this point, the maximum particle size of the offset toner 6 was 20 μm. Images of this size are not perceived. When fixing the next page, the next recording paper 4
In addition, 6 out of the 8 were re-transferred and removed. When this is repeated, the offset toner 6 on the surface of HR1
The particle size of the was gradually increased. By the way, the smallest pattern of the images fixed by the fixing device is an image displayed as a dot, for example, a decimal point in a numerical sequence. When the offset toner 6 is re-transferred onto the recording paper 4, if the size of the black spot due to the re-transferring that appears on the recording paper 4 at that time is equal to the size of this decimal point, it is recognized as an image. The size of the decimal point of the recording device in this embodiment is
The diameter is 0.25 mm, and as a value that can be clearly distinguished from this, in the present fixing device, the occurrence of black spots due to the retransfer of offset toner having a diameter of 0.1 mm is allowed. When the experiment was further continued, a large particle size offset toner 6 appeared on the surface of the HR1 to generate a black spot having a diameter of 0.1 mm on the recording paper 4 when fixing of about 150 pages was completed. The brush 7 of the brush roller 3 has a diameter of 10 μm, and the bristle density thereof is staggered at intervals of 20 μm. With this brush, the offset toner 6 can be disturbed by contact and decomposed into small particles having a particle diameter of 15 μm or less. From the above experimental results, the brush roller 3 was brought into contact with the HR 1 every time 150 pages were printed. Even in this case, however, when printing for a long period of time, black dots due to the offset toner 6 having a diameter of 0.1 mm or more are recorded on the recording paper 4. Appeared in. It has been clarified that the reason for this is that the offset toner 6 is decomposed by the contact of the brush roller 3, but is not removed from the surface of the HR 1 at that time. Furthermore, as a result of detailed experiments, HR1 immediately after contact with the brush roller 3
It was found that the presence of the offset toner 6 on the surface corresponds to the situation at the time of fixing about 80 pages from the state where the offset toner 6 does not exist at all on the surface of the HR1. From this result, it was decided that the brush roller 3 was brought into contact with the HR 1 every time 70 pages were fixed, and the offset toner 6 was decomposed. As a result, the appearance of black dots that can be recognized as an image on the recording paper 4 is eliminated, and the recording paper 4 used for printing is not printed.
It has become possible to remove the offset toner 6 by using. According to the present embodiment, the offset toner 6 can be satisfactorily removed by using the recording paper used for printing without causing erroneous printing. Further, since the brush roller 3 is intermittently brought into contact with the HR1, the brush roller 3 and the HR1
Wear life can be extended.

<Third Embodiment> The configuration of this embodiment is the same as that of FIG.

In the second embodiment described above, there is no occurrence of black spots due to the offset toner 6 recognized as an image, but the existence of these black spots can be recognized by the user. Although the presence of the black spots does not cause erroneous printing, it may not be positively accepted by the user and may be recognized as stains on the recording paper, and should preferably be eliminated.
Especially when not staring, if it is a black spot of about 50 μm, it is often not noticed visually. Therefore, 50
In order to prevent the generation of black spots of μm or more, in this embodiment, the contact period of the brush roller 3 was set to every 5 pages, according to the same experimental result as that performed in the first embodiment. As a result, in this embodiment, there is an effect that no visually recognizable black spots are generated on the recording paper 4.

<Embodiment 4> In the brush roller 3 of Embodiments 1 to 3, since the releasability of the brush 7 from the offset toner 6 is poor, when the offset toner 6 is repeatedly disassembled, the offset existing on the surface of the HR1. The toner may transfer to the brush roller 3 and the offset toner 6 may adhere to the brush 7. In a remarkable case, the transferred offset toner 6 acts as a binder, and 72 brushes or 3 brushes are used.
Sometimes books are combined. In this case, the diameter of the brush 7 is equal to the increase, so that the offset toner 6
Reduce the ability to decompose. In this embodiment, in order to improve the releasing effect of the brush 7 of the brush roller 3 on the offset toner 6 and prevent the transfer of the offset toner 6 from the HR 1 to the brush roller 3, the brush 7 is coated with a fluororesin. According to this embodiment, the offset toner 6 does not adhere to the brush 7 of the brush roller 6, and even if the offset toner 6 is repeatedly decomposed, the ability of the brush roller 3 to decompose the offset toner 6 does not decrease. The same effect can be obtained by using a fluororesin as the material of the brush 7.

<Embodiment 5> FIG. 2 is a sectional side view of the brush roller 3 used in this embodiment in a rotating state. 8
Is a core metal, 9 is a regulation layer, 10 is a release agent, 11 is a hole, and 12 is air. The brushes 7 are planted on the regulation layer 9 wound on the surface of the cylindrical cored bar 8, and the release agent 10 is provided in the space inside the cored bar 8.
And the core metal 8 has a hole 11 for the release agent 10 to flow out.
Is provided. In this embodiment, Nomex paper is used as the material of the regulation layer 9, and the release agent 10 is 40,000 CS (centistokes: the kinematic viscosity coefficient of oil, the greater the stickiness at room temperature) at room temperature. Silicone oil is used. The brush roller 3 is used similarly to the fixing device described in the first embodiment. The brush roller 3 is heated by HR1, the viscosity of the release agent 10 inside is reduced, and the air 12 inside is released.
Pressure increases. Further, the rotation of the brush roller 3 causes a centrifugal force to act on the release agent 10. Due to the synergistic effect of the three effects of the decrease of the viscosity of the release agent 10, the increase of the internal pressure, and the action of the centrifugal force, the release agent 10 flows out through the hole 11 while the brush roller 3 is rotating, and HR1 Applied to the surface. In the present embodiment, the release agent 10 enclosed in the brush roller 3 is applied to the surface of the HR1 to improve the release effect of the HR1, and thereby the offset toner 6 transferred from the recording paper 4 to the HR1. This has the effect of reducing the amount. Furthermore, since the release agent 10 is applied to the HR 1 via the brush 7, the release effect of the brush 7 is also improved. Therefore, from HR1 to brush 7
There is also an effect of preventing the transfer of the offset toner 6 to the.

<Embodiment 6> The fixing device of this embodiment has the same structure as that of the fixing device described in Embodiment 5, but the brush roller 3 is provided so as to be able to come into contact with and separate from the HR 1. The dimming of the contact of the brush roller 3 with the HR 1 is set in the same manner as described in the second embodiment. According to this embodiment, since the amount of the offset toner 6 is reduced by applying the release agent 10 to the HR 1, the brush roller 3 is moved to the HR.
There is an effect that the period of contact with 1 can be extended.

<Embodiment 7> The fixing device of this embodiment has the same structure as that of Embodiment 6. FIG. 3 shows the outflow characteristics of the release agent 10 during the continuous rotation of the brush roller 3. Reference numeral 13 represents the flow rate Q of the releasing agent flowing out, and 14 represents the continuous rotation time t. The release agent flow rate 13 decreases as the continuous rotation time 14 increases, and finally becomes zero, and the release agent 10 stops flowing out. It was confirmed that the reason for this is that the release agent 10 flows out to expand the space filled with the air 12 inside the brush roller 3, but the air 12 has a constant mass, resulting in a decrease in the air pressure. It was confirmed that the following method is suitable for preventing the decrease in the release agent flow rate 13 due to the decrease in air pressure. The rotation of the brush roller 3 is stopped at regular intervals, the mold release agent 10 existing on the inner surface of the brush roller 3 is dropped in the direction of gravity, and the holes 11 are penetrated by the air 12 to blow the air 12 to the brush roller 3. The internal pressure can be increased by replenishing. In this embodiment, as a result of previously grasping the lowering characteristic of the release agent flow rate 13, when the continuous rotation time 14 reaches 12 hours, if the brush roller 3 is separated from the HR1 and the hole 11 is penetrated, the HR1 is good. Then, the release agent 10 is applied. Therefore, the separation period of the brush roller 3 is
It is set to 12 hours of continuous rotation.

<Embodiment 8> The brush roller 3 of this embodiment is shown in FIG.

Reference numeral 15 is an internal pressure detection film, and 16 is a pressure conversion circuit.

The basic structure of this embodiment is the same as that of the seventh embodiment, except that the brush roller 3 is provided with an internal pressure detecting film 15 made of an elastic material. When the internal pressure decreases, the internal pressure detection film 15 is displaced inward, and the internal pressure can be detected from the displacement amount via the pressure conversion circuit 16. The internal pressure is detected only when the brush roller 3 is rotating, and when the internal pressure becomes 1 atmospheric pressure or less, the brush roller 3 is separated from the HR1. Thereby, the release agent 10 is satisfactorily applied to the HR 1.

<Embodiment 9> The configuration of this embodiment is the same as that described in Embodiment 7. In the sixth embodiment, the fixing device in which the brush roller 3 is intermittently contacted in order to decompose the offset toner 6 has been described, but in this embodiment as well, the brush roller 3 is brought into contact with the HR1 in the same manner as in the sixth embodiment.
The contact period is every 200 pages printed. If this cycle is displayed as time, in the present fixing device, the brush roller 3
Will be 200 seconds. At this time, the non-contact period is 190 seconds. On the other hand, the release agent 10 is dropped downward by gravity, and the holes 11 located above are released into the air 12
The rotation stop time of the brush roller 3 required for the penetration is 300 seconds. Therefore, the separation of the flow rate 13 of the release agent cannot be prevented only by separating the brush roller for a short time for disassembling the offset toner 6. In this embodiment, the brush roller 3 is brought into contact with the HR1 for 10 seconds every 200 pages are printed. Further, when this printing mode is continuously performed for 12 hours, the brush roller 3 is separated from the HR 1 for 300 seconds, and at this time, the printing is stopped. As a result, the release agent 10 can be satisfactorily applied to the HR1, so that the cycle of contacting the brush roller with the HR1 can be greatly extended, and as a result, the wear life of the brush roller 3 and the HR1 can be significantly extended. It has the effect that

<Embodiment 10> The structure of this embodiment is the same as that of Embodiment 2.
However, a tube made of fluororesin is used for the outer layer of HR1. For example, there are materials under the trade names of PTFE (polytetrafluorethylene resin) and PFA (tetrafluoroethylene-fluoroalkoxy ethylene copolymer resin). By the way, PFA is applied to the outer layer of HR1.
When the coating is used, the outer circumference is cut at the final stage of the manufacturing process of HR1 in order to make the outer cover thickness constant. This peripheral cutting causes a problem that surface smoothness is impaired.

When a fluororesin tube is used for the outer layer of HR1, the outer peripheral cutting step is not required, so HR1
Since the surface smoothness of No. 2 is kept good, the amount of the offset toner 6 is remarkably reduced. In this embodiment, since the fluororesin tube roller is used, the amount of the offset toner 6 is remarkably small, so that there is an effect that the cycle of contacting the brush roller 3 can be extended.

<Embodiment 11> An embodiment of the present invention will be described below with reference to FIG. FIG. 5 is a sectional side view of the fixing device of this embodiment. Reference numeral 17 is a wiping roller. Wiping roller 17
Is provided so as to be able to come into contact with and separate from the HR 1, and the wiping roller 17
Contact the HR1, all the offset toner 6 present on the surface of the HR1 is transferred to the wiping roller 17, and the HR
Removed from 1. The material forming the contact surface of the wiping roller 17 with the HR is sponge rubber having excellent wiping properties. Also in this embodiment, due to the same phenomenon as described in the second embodiment, the offset toner 6 particles expand as the number of printed pages increases. In this embodiment, the wiping roller 1 is set before the offset toner 6 reaches a size recognizable as an image.
7 contacts HR1. This contact period was set at 150 pages from the same phenomenon observation as described in Example 2. In the case of the wiping roller 17, this set value is longer than the brush roller contact period because all the offset toner 6 existing on the surface of HR1 is removed from HR1 at the time of contact. As a result, the appearance of black dots that can be recognized as an image on the recording paper 4 disappears, and the offset toner 6 can be removed using the recording paper 4 used for printing. Further, according to the present embodiment, the wiping roller 17 wipes the offset toner 6 only at the time of contact, so that the wiping roller 17 is less contaminated by the offset toner 6 and the period until the replacement of the wiping roller 17 is significantly reduced. It can be extended.

<Embodiment 12> An embodiment of the present invention will be described below with reference to FIG. FIG. 6 is a sectional side view of the fixing device of this embodiment. The wiping roller 16 and the brush roller 3 are provided so as to be able to come into contact with and separate from the HR 1. The brush roller 3 operates similarly to the ninth embodiment. However, in this embodiment, printing is continuously performed even during a period in which the brush roller 3 is separated by 300 seconds after printing for 12 hours. Only during that period, the wiping roller 16 contacts the HR1.
According to this embodiment, the offset toner 6 can be satisfactorily removed without interrupting printing.

<Embodiment 13> An embodiment of the present invention will be described below with reference to FIG. FIG. 7 is a sectional side view of the fixing device of this embodiment. Reference numeral 18 is an offset toner disassembling device. The offset toner decomposing device 18 transmits ultrasonic waves to the HR1.
Emit to the surface. As a result, the offset toner 6 existing on the surface of the HR1 vibrates and decomposes into small particles that cannot be recognized. That is, ultrasonic vibrations are transmitted to the melted offset toner, and the vibration waves are transmitted on the surface thereof,
The surface of the molten toner is deformed into a waveform, and the difference between the peaks and the valleys of the wavefront becomes larger as the vibration energy is further strengthened, and finally, the particles can be decomposed by acting to tear the molten toner. . The operation timing of the offset toner disassembling device 18 is the same as the contact timing of the brush roller 3 described in the second embodiment. According to this embodiment, since the offset toner 6 can be decomposed without contact, there is an effect that the offset toner 6 does not adhere to the offset toner decomposition means.

<Embodiment 14> The construction of this embodiment is the same as that of FIG. 7, except that the offset toner disassembling device 18 is HR1.
A high-frequency voltage is applied to the surface facing the. The high-frequency potential of the offset toner decomposition device 17 causes the offset toner 6 to vibrate and decompose into unrecognizable small particles.
That is, when an electrode is installed near the molten toner and a voltage is applied to the electrode, an electric charge induced by the electrode is generated inside the toner, and a suction force acting on the electrode acts on the toner. At the same time, due to the image charge generated on the heat roll, a suction force toward the heat roll also acts. As a result, the toner is deformed to have a constricted center. At this time, the deformation of the toner is a mixed state of viscous deformation and elastic deformation, and when the voltage application is stopped, the diameter of the constricted portion becomes thicker because it is restored by the amount of elastic deformation, but it cannot be completely restored. When this operation is repeated, the narrowed part gradually becomes thinner and is finally torn.

Offset toner disassembling device 18 of this embodiment
The operation timing of is the same as that described in the thirteenth embodiment. According to this embodiment, since the offset toner 6 can be decomposed without contact, there is an effect that the offset toner 6 does not adhere to the offset toner decomposition means.

<Embodiment 15> The construction of this embodiment is the same as that of FIG. 7, except that the offset toner disassembling device 18 is HR1.
A xenon flash lamp is arranged on the surface facing the. The light emission period of the xenon flash lamp during continuous light emission is given by L / V, where L is the length of the flash light irradiation region in the circumferential direction on the surface of HR1 and V is the peripheral speed of HR1. The offset toner 6 is abruptly heated by the flash light of the xenon flash lamp, and therefore melts explosively with boiling and chemical change. As a result, it decomposes into unrecognizable particles. The timing of continuous light emission and light emission stop of the xenon flash lamp of the offset toner disassembling device 18 of the present embodiment is the same as that described in the thirteenth embodiment. According to this embodiment, the offset toner 6 can be decomposed in a non-contact manner, so that the offset toner 6 does not adhere to the offset toner decomposition means.

<Embodiment 16> The construction of an electrophotographic recording apparatus to which this embodiment is applied is shown in FIG. In FIG. 9, the surface of the photoconductor 9a rotating in the direction of the arrow 9j is uniformly charged by the charger 9b, and the electrostatic latent image 9h corresponding to the recording image signal is formed by the exposure 9c. The toner is attached by the imager 9d to which the bias 9i is applied according to the potential of the latent image, and the toner image 9k is formed. The resulting image is the transfer device 9e
Is transferred to the recording paper 4 and sent to the fixing device 9l to permanently fix the toner image on the recording paper. Here, as the means 9f for giving the timing to start the disassembling process of the offset toner disassembling means not provided in the fixing device 9l, printing is performed in the process in which the particle size of the offset toner grows as described in the first embodiment. It is possible to use a logic circuit including a counter for counting the number of pages to be printed and a control circuit for outputting a signal when the number of pages reaches a predetermined number and resetting the counter to count the number of pages to be printed subsequently.
According to this, it is possible to construct a printer that gives a timing at which the offset toner is automatically decomposed due to a human being.

Further, the printer may be connected to an external computer device to determine the timing for disassembling in response to a command from the computer, or the operator may select an arbitrary timing from an operation panel provided on the printer device. The point is that if the characteristics of how the particle size of the offset toner grows are obtained in advance, the timing at which the offset toner should be decomposed can be determined without directly measuring the particle size. It can be given.

Although the number of printed pages is counted in the above, if the amount and type of recorded information (type of pattern such as character, photograph, solid paint) can be known before printing,
Since the toner consumption amount can be actually predicted for the print information, the information amount or the type of the pattern may be used as the timing giving evaluation means based on the print information.

<Embodiment 17> Another embodiment will be described with reference to FIGS.

FIG. 9 is a diagram showing a change over time in the power supply current of the HR drive motor from the time when the front end of the recording paper is inserted when the recording paper is inserted through the contact surface formed between the HR and the BR.

I is a current, t is a time, a is a front end of the recording sheet, b is a rear end of the recording sheet, Δi is a current change width, and Δt is a time width corresponding to the current change width. . This figure shows a case where a recognizable offset occurs in the first sheet passing in the non-offset band 21. In this embodiment, an offset larger than the point of 50 μm is set as a recognizable offset. When the recording paper is inserted through the contact surface formed between the HR and the BR, the inventors of the present invention generate a current fluctuation of the power supply current of the HR drive motor as shown in FIG.
It was found that a recognizable offset is generated in response to the change in current even in the inside. In FIG. 9, a range indicated by a broken line indicates a range in which a recognizable offset has occurred.
In this way, a recognizable offset is generated corresponding to a large current change regardless of the increase / decrease of the current change due to the current fluctuation. By the way, such a current fluctuation of the power supply current of the HR drive motor is caused by an impact due to a rush of the front end of the recording paper when the recording paper is inserted and a vibration generated thereby
The cause is the load fluctuation of the R drive motor. The load fluctuation of the HR drive motor reflects that the recording paper or toner causes shearing between the HR surface and the HR surface inside the contact surface formed between the HR and the BR. Due to the shear acting on the interface between the toner and the HR surface, the toner is transferred to the HR surface and offset occurs.

FIG. 10 is a diagram showing a range in which a recognizable offset occurs in the relationship between the current change width Δi and the time width Δt. The shaded area 22 is the non-offset band 2
Within 1, the range in which a recognizable offset occurs is shown. A large amount of the data shown in FIG. 9 was collected, and the current change width Δi
And the time width Δt. From this result, the change rate Δi / Δt of the current change Δi is 17.
It was revealed that a recognizable offset occurs in the range of 5 A / s or more and the time width Δt of 28.5 ms or more. Further, when a DC motor is used as the HR drive motor, a direct current may be used for Δi, but in the case of a motor driven by a cross current, for example, an induction motor, it is effective for Δi. It was also clarified that the same results as in FIG. 10 can be obtained by using the values.

From the above results, according to this embodiment, HR
By setting the current change or the effective value change of the current in the current fluctuation of the drive motor within the range in which the rate of change Δi / Δt is 17.5 A / s or less or the time width Δt is 28.5 ms or less, The offset amount can be significantly reduced.

<Embodiment 18> Another embodiment will be described with reference to FIGS.

FIG. 11 is a side view showing the pressing mechanism for HR and BR. 23 is a pressing member, 24 is the center of rotation of the BR, 2
5 is the rotation center of the pressing member, 26 is the pressing spring, 27 is the joint position of the pressing spring 26 in the pressing member 25, l is the distance from the BR rotation center 24 to the pressing member rotation center 25,
L is the distance from the rotation center 25 of the pressing member to the joint position 27 of the pressing spring 26 on the pressing member 25. The pressing spring 26 lifts the pressing member 23 by a spring force, and accordingly, the pressing member 23 rotates upward with the rotation center 25 as a fulcrum to press the BR against the HR. Although only one side surface is shown in the figure, a similar mechanism is provided on the other side surface.

The force with which BR is pressed against HR is the pressing force F
If the spring constant of the pressing spring 26 is k and the elongation is x, the pressing force F ₀ when the recording paper is not passed is given by the following equation.

F ₀ = 2 · k · (L / l) · x (1) On the other hand, when the recording paper is passed, if the thickness of the recording paper is δx, the pressing force F ₁ Is given by the following equation.

F ₁ = 2k (L / l)  (x + δx (L / l)) (2) By the way, the current fluctuation of the power supply current of the HR drive motor described in Embodiment 17 is the recording paper. This is caused by the rush impact of the front end of the recording paper at the time of insertion and the load fluctuation of the HR drive motor due to the vibration generated thereby. Therefore, the smaller the rush impact force at the front end of the recording paper, the smaller the current fluctuation. The rush impact force at the front end of the recording paper is proportional to the difference in pressing force depending on the presence or absence of the recording paper. Letting the rush impact force be Fi, this can be expressed as follows: Fi ∝F ₁ −F ₀ (3) Further, in the configuration of this embodiment, F ₁ −F ₀ is expressed by the following equation.

F ₁ −F ₀ = 2 · k · (L / l) ² · δx (4) Here, the pressing force when the recording paper is passed and the case where the recording paper is not passed The value obtained by dividing the difference in the pressing force of (1) by the thickness of the recording paper is defined as the impact coefficient K. Since the value obtained by multiplying the impact coefficient K by the thickness of the recording paper is proportional to the rush impact force, the lower the impact coefficient K, the smaller the rush impact force. In this embodiment,
From the equation (4), the impact coefficient K becomes 2 · k · (L / l) ² , and the relationship between the impact coefficient and the rush impact force described above can be easily understood from the equations (3) and (4). It can be understood. Further, if the impact coefficient K is reduced, the rush impact force is reduced, and thus the current fluctuation of the power supply current is also reduced.

The inventors conducted a fixing experiment by changing the impact coefficient K and obtained the following results. FIG. 12 shows the result of an experiment in which the impact coefficient K was changed in the non-offset band 21. In the current fluctuation range shown in this figure, when there is a current change in the shaded area 22 shown in FIG. 10 in the current fluctuation of the HR drive motor generated in the experiment, there is a cross mark, and there is a current change in the shaded area 22. If not, a circle is shown. The cognitive offset shown in FIG. 12 indicates whether or not a perceptible offset has occurred in this experiment. The recognizable offset standard is the same as that in the seventeenth embodiment. According to FIG. 12, the impact coefficient K is 4.0 × 1.
It can be seen that at a value of 0 ⁵ (N / m) or less, the change in current is small and no recognizable offset occurs.

As shown in FIG. 9, the ejection impact of the trailing edge of the recording paper also occurs during ejection b, which is also proportional to the impact coefficient K. In the case of continuously passing the recording paper, there is a concern that a recognizable offset may occur when the next recording paper plunges in while the vibration due to the ejection impact continues, but in the present embodiment, in FIG. From the result, the impact coefficient K is 4.0 × 10
Below ⁵ (N / m), there is no possibility that the change in the current within the shaded area 22 shown in FIG.

According to this embodiment described above, the impact coefficient K
Is set to 4.0 × 10 ⁵ (N / m) or less, the offset amount in the non-offset band 21 can be significantly reduced. Further, even when the recording paper is continuously passed, the offset amount in the non-offset band 21 can be greatly reduced.

<Embodiment 19> Another embodiment of the present invention will be described below with reference to FIG. FIG. 13 is a sectional side view of the fixing device according to the embodiment of the present invention. Reference numeral 34 is a recording paper guide. In this embodiment, HR1 is heated and BR2 has an elastic layer to support the recording paper 4. Other configurations and operations of the present fixing device are the same as those of the fixing device described in FIG.
The mounting position of the recording paper guide 34 at the insertion port of the recording paper 4 to the fixing device is different.

As described above, when the temperature of BR2 is low, the offset toner 6 transferred to HR1 may be transferred to BR2 and fixed there, causing stain on BR2. According to experiments conducted by the inventors, this type of BR2 stain is likely to occur when the temperature of BR2 is 100 ° C. or lower. Even if the offset toner disassembling device is installed in the HR 1 and the recognizable offset toner 6 is lost, the BR 2 may accumulate due to cooling of the offset toner 6 and may develop into stains on the BR 2. . When the BR2 becomes dirty, the dirt is transferred to the recording paper 4 at the time of restarting as described above, which causes a problem that erroneous printing occurs.

In this embodiment, the mounting position of the recording paper guide 34 is set low, and the front end of the recording paper 4 is HR1 and BR.
It hits BR2 before it is inserted into the contact surface of No.2. At that time, the front end of the recording paper 4 has a function of transferring the offset toner 6 fixed to the BR 2 to the recording paper 4. That is,
The front end of the recording paper 4 has a function of cleaning the BR 2. Since the recording paper 4 repeatedly sent cleans the BR 2 each time, the offset toner is not accumulated in the BR 2.

According to the present embodiment described above, since the offset toner is not accumulated in the BR2, it is possible to prevent the BR2 from being contaminated and prevent the erroneous printing due to the stain.

[0065]

According to the present invention, the particles of the offset toner that can be recognized when it is fixed on the recording paper can be decomposed into the unrecognizable offset toner. There is an effect that the offset toner can be removed without causing printing.

Further, since only the offset toner that can be recognized when it is fixed on the recording paper can be wiped off on the fixing roller, there is an effect that the offset toner can be removed without causing erroneous printing.

Further, it is possible to reduce the degree of load fluctuation of the HR drive source at the time of fixing due to a rushing impact of the front end of the recording paper at the time of inserting the recording paper or a discharging impact at the rear end of the recording paper at the time of discharging. There is an effect that the amount of offset toner in the non-offset band can be reduced.

Further, since the front end of the recording paper is collided with the BR before being inserted into the contact surface between the HR and the BR, the BR is provided with the function of cleaning, so that the BR2 can be prevented from being soiled. There is an effect that it is possible to prevent the occurrence of erroneous printing due to it.

[Brief description of drawings]

FIG. 1 is a cross-sectional side view of a fixing device according to an embodiment of the present invention.

FIG. 2 is a sectional side view of a brush roller according to an embodiment of the present invention.

FIG. 3 is a diagram showing an outflow characteristic of a release agent during continuous rotation of a brush roller.

FIG. 4 is a sectional side view of a brush roller according to an embodiment of the present invention.

FIG. 5 is a sectional side view of the fixing device according to the embodiment of the present invention.

FIG. 6 is a cross-sectional side view of the fixing device according to the exemplary embodiment of the present invention.

FIG. 7 is a cross-sectional side view of the fixing device according to the embodiment of the present invention.

FIG. 8 is a configuration diagram of an electrophotographic recording apparatus that is an embodiment of the present invention.

FIG. 9 is a diagram showing a change over time in the power supply current of the HR drive motor from the time when the front end of the recording paper has entered.

FIG. 10 is a diagram showing a range in which a recognizable offset occurs.

FIG. 11 is a side view showing a pressing mechanism for HR and BR.

FIG. 12 is a result of an experiment in which the impact coefficient K is changed.

FIG. 13 is a cross-sectional side view of the fixing device according to the embodiment of the present invention.

FIG. 14 is a diagram showing generation characteristics of offset toner.

[Explanation of symbols]

1 ... Heat roller, 2 ... Backup roller, 3 ... Brush roller, 4 ... Recording paper, 5 ... Toner, 6 ... Offset toner, 7 ... Brush, 10 ... Release agent, 11 ... Hole, 12 ... Air, 13 ... Release Mold material flow rate, 14 ... Continuous rotation time, 15 ... Inner pressure detection film, 17 ... Wiping roller, 18 ... Offset disassembling device, 21 ... Non-offset band, 22 ... Range where recognizable offset occurs, 34 ... Recording paper guide , I ... current, t ... time, Δi ... current change width, Δt ... current change, K
… Impact coefficient.

Front Page Continuation (72) Inventor Takashi Suzuki 2-6-2 Otemachi, Chiyoda-ku, Tokyo Hitsukiko Co., Ltd. (72) Inventor Kazuo Uno 2-6-2 Otemachi, Chiyoda-ku, Tokyo Inside Ritsukoki Co., Ltd.

Claims (31)

[Claims] 1. A fixing device for contacting and fixing a toner image formed on a recording paper to a fixing roller, comprising a particle size reducing means for reducing the particle size of the offset toner particles transferred to the surface of the roller. Characterizing fixing device. 2. In a fixing device for fixing a toner image formed on a recording paper by bringing it into contact with a fixing roller, a means for heating at least one of the rollers and a small particle size of offset toner particles transferred to the surface of the roller. A fixing device comprising: a reducing means for reducing the particle diameter, and a means for re-transferring the reduced offset toner particles onto a recording paper to be printed. 3. The fixing device according to claim 1, wherein the particle size reducing means is provided separately from the surface of the roller. 4. The fixing device according to claim 1, wherein the particle size reducing means is a mechanical vibration generating means. 5. The fixing device according to claim 4, wherein the mechanical vibration generating means is an ultrasonic wave generating means. 6. The fixing device according to claim 4, wherein the mechanical vibration generating means includes a crossing voltage applying means. 7. The fixing device according to claim 1, wherein the particle size reducing means is a light generating means. 8. The fixing device according to claim 1, wherein an outer coat layer of a tube made of fluororesin is formed on the surface of the roller. 9. The fixing device according to claim 1, wherein the particle size reducing means is a brush having a brush. 10. The fixing device according to claim 9, wherein a film of fluororesin is formed on the surface of the brush. 11. The fixing device according to claim 9, wherein the brush is made of a fluororesin. 12. The fixing device according to claim 9, wherein the brush is a hollow cylindrical member, and a brush formed on the outer main surface of the brush, a gas sealed inside the hollow cylinder, and a separating member. A fixing device comprising a mold agent and an outflow means for causing the release agent to flow out to the outer main surface. 13. The fixing device according to claim 12, wherein the sealed release agent detects a decrease in the amount of outflow of the release agent to the outer main surface through the outflow means. A fixing device comprising: a separating unit that separates the roller brush from the fixing roller based on a detection result of the detecting unit. 14. The fixing device according to claim 12, wherein the sealed release agent flows out to the outer main surface through the outflow means, and the pressure inside the hollow cylinder is higher than a predetermined value. A fixing device, characterized in that the roller brush is separated from the fixing roller when lowered. 15. The fixing device according to claim 14, wherein the predetermined value is atmospheric pressure. 16. The fixing device according to claim 13, wherein the predetermined value is determined based on that the outflow amount of the release agent reaches a predetermined value. 17. A pair of fixing rollers are provided, at least one of the fixing rollers is heated, and a recording paper carrying a toner image is passed through the contact surfaces of the pair of fixing rollers facing each other.
In a fixing device for fixing the toner image by bringing the toner image into contact with the fixing roller and melting the toner image, there is provided means for reducing the size of offset toner particles formed by transferring the melted toner to the surface of the fixing roller. A fixing device characterized in that offset toner particles having a reduced particle diameter are retransferred to a recording paper to be printed by a means for changing the particle diameter. 18. The fixing device according to claim 17, wherein the particle size reducing means is in contact with at least one of the fixing rollers. 19. The fixing device according to claim 18, wherein the timing at which the particle size reducing means contacts the fixing roller is
The fixing device is set by setting the particle size of the offset toner particles to a size that can be visually recognized. 20. A fixing device for contacting and fixing a toner image formed on a recording paper to a fixing roller, wherein a means for heating at least one of the rollers and an offset toner particle transferred to the surface of the roller are wiped off. A first wiping means provided to be able to come into contact with and separate from the roller, and re-transferring the offset toner particles existing on the surface of the roller onto the recording paper to be printed while the first wiping means is separated from the roller. And a second wiping means for wiping off with a fixing device. 21. A pair of fixing rollers, wherein at least one of the fixing rollers is heated, a recording paper carrying a toner image is inserted into a contact surface of the fixing roller, and the toner image is fixed by the heating. A fixing device for fixing by fusing to a recording paper by bringing it into contact with a roller, having a wiping means and a small particle diameter means for the offset toner particles to which the toner is fused and transferred to the surface of the fixing roller, The wiping means and the particle size reducing means are provided so as to be able to come into contact with and separate from the fixing roller, and the wiping means contacts the fixing roller while the particle size reducing means is separated from the fixing roller. Fixing device. 22. A fixing method of fixing at least one of a toner image formed on a recording paper by bringing it into contact with a heated fixing roller to reduce the size of offset toner particles transferred to the surface of the roller. And a step of re-transferring the reduced-sized offset toner particles onto a recording paper to be printed. 23. A pair of fixing rollers, wherein at least one of the fixing rollers is heated, a recording paper carrying a toner image is inserted into a contact surface of the fixing roller, and the toner image is brought into contact with the fixing roller. In the fixing method in which the toner is melted and then fixed, the offset toner particles formed by transferring the melted toner to the surface of the fixing roller are reduced in size, and the offset toner particles reduced in size are printed. And a step of retransferring the recording paper to the recording paper. 24. In an electrophotographic recording device having a fixing device for fixing a toner image formed on a recording paper by bringing it into contact with a fixing roller, a small particle size for reducing the offset toner particles transferred to the surface of the roller. An electrophotographic recording apparatus, comprising: an atomizing unit; and an imparting unit that imparts a timing for starting the atomizing of the offset toner particles to the atomizing unit. 25. The electrophotographic recording apparatus according to claim 24, wherein the imparting means imparts the timing for starting the reduction in particle size based on the amount of information recorded on the recording paper to be printed. Electrophotographic recording device. 26. In a fixing device having at least a fixing roller and a drive source for rotating the fixing roller, wherein a toner image formed on a recording sheet is fixed by bringing the toner image into contact with the fixing roller. A fixing device characterized in that the change or the effective value change of the current is set within a range in which the time change rate Δi / Δt is 17.5 A / s or less or the time width Δt is 28.5 ms or less. 27. The fixing device according to claim 25, wherein the drive source is a motor. 28. At least two fixing rollers, a drive source for rotating the fixing rollers, and a mechanism for pressing the fixing rollers together, the toner image formed on the recording paper is inserted between the fixing rollers. In the fixing device for fixing, the impact coefficient of the pressing mechanism is 4.0 × 10 ⁵ (N / m) or less. 29. The fixing device according to claim 1, wherein the fixing device has a drive source for rotating the fixing roller, and a current change or a change in effective value of the current due to a current change of the drive source is changed with a time change rate Δi. / Δt is set to 17.5 A / s or less or time width Δt is set to a range of 28.5 ms or less. 30. The fixing device according to claim 1, wherein the fixing roller comprises two rollers, and has a drive source for rotating the fixing roller and a mechanism for pressing the fixing rollers, and the impact coefficient of the pressing mechanism. Is less than 4.0 × 10 ⁵ (N / m). 31. The fixing device according to claim 1, wherein one of the fixing rollers supports the recording medium and the other roller heats the toner on the recording medium. A fixing device, characterized in that the recording body is brought into contact with a roller on the side supporting the recording body before the recording body is inserted.