JP3077326B2 - Fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device, and more particularly to a fixing device used in an electrophotographic copying machine, a laser beam printer, and the like.

[0002]

2. Description of the Related Art Conventionally, a laser beam printer or the like has a fixing device for fixing toner transferred to a sheet. This fixing device is, for example, shown in FIG.
The configuration shown in FIG.

The fixing roller 121 has a hollow cylindrical shape.
It is rotatable. The pressure roller 122, which is a pressure unit, is also cylindrical, and can rotate while being pressed against the fixing roller. Inside the fixing roller 121, a heating element 123,
A plurality of heat conductors 124 are provided. Heating element 123
Is constituted by an electric resistor having a long plate shape, and generates a high temperature when a voltage is applied. The heating element 123 is fixed to a frame or the like of a laser beam printer by a support member (not shown).
Each heat conductor 124 has a shape like a cylinder cut in half along its axis. These heat conductors 123 are fixed to both surfaces of the heat generator 123, and the heat conductor 124 is in contact with most of the inner wall of the fixing roller 121. When the fixing roller 121 rotates, the heat conductor 124 slides while contacting the inner wall of the fixing roller 121.

In a laser beam printer or the like having a conventional fixing device configured as described above, the power of the laser beam printer is turned on. Then, a predetermined voltage is applied to the heating element 123, and the temperature of the heating element 123 becomes high. The heat generated from the heating element 123 propagates to the inner wall of the fixing roller 121 via the heat conductor 124. The heat conductor 124 is
Because it is in contact with most of the inner wall of the fixing roller 121,
The entire fixing roller 121 is uniformly heated. The temperature of the outer wall of the fixing roller 121 is set to a temperature suitable for fixing (for example, 150
(-200 ° C.) until the fixing roller 121 is heated. In this state, the fixing roller 121 and the pressure roller 122
, While rotating in the opposite directions while contacting the sheet, the sheet to which the toner adheres passes while contacting the fixing roller 121 and the pressure roller 122. Fixing roller 121 and pressure roller 1
At the contact portion (nip portion) with the toner 22, the toner on the sheet is melted by the heat of the fixing roller 121 and is fixed on the sheet. As the fixing roller 121 and the pressure roller 122 rotate, the sheet is conveyed to a paper discharge roller (not shown), and is discharged to a paper discharge tray (not shown) via the paper discharge roller.

[0005]

However, in the conventional fixing device, after the power is turned on to a laser beam printer or the like having the fixing device, a relatively long time is required until the fixing roller 121 reaches a temperature suitable for fixing. It took a long time. During this time, the operator cannot use the laser beam printer, and there is a problem that the operator has to wait for a long time.

Incidentally, if the temperature of the heating element is made higher to shorten the time required for heating the fixing roller 121, the time required for heating the fixing roller 121 can be reduced. However, a new problem arises in that the current consumption of the heating element increases and the temperature inside the laser beam printer increases.

Further, with the rotation of the fixing roller 121,
When the sheet is peeled off from the nip portion, the following problem also occurs.

That is, since the entire fixing roller is heated, even when the sheet is peeled off from the fixing roller 121, the toner on the sheet melts without fixing due to the heat of the fixing roller around the nip portion. Remains. For this reason, there is a problem that the so-called offset phenomenon occurs in which the heat-melted toner easily adheres to the fixing roller, and the toner adhered to the fixing roller adheres to the sheet again.

Further, the toner on the sheet remains hot melt without being fixed by the heat of the fixing roller around the nip portion. Therefore, the sheet hardly peels off from the fixing roller 121 due to the adhesive force of the hot melted toner. Become. Then, the sheet is wrapped around the fixing roller, causing a problem that jamming occurs.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fixing device which shortens the time required for heating a fixing roller, prevents an offset phenomenon, and provides a sheet in which a sheet is easily peeled off from the fixing roller. I have.

[0011]

According to a first aspect of the present invention, there is provided a fixing device comprising: a rotatable hollow fixing roller; a heating element disposed in the fixing roller; A heat conductor for transmitting the heat to the fixing roller, and a pressurizing unit for bringing the sheet with the toner adhered into contact with a part of the outer wall of the fixing roller, and the heat generator via the heat conductor. In the fixing device in which the heated fixing roller heats and melts the toner on the sheet in contact with the fixing roller and fixes the toner to the sheet, the heat conductor has elasticity, and With the above sheet
Inner wall part and upper part of the fixing roller corresponding to the contacting part
The serial heating element abuts pressing them with, concentrate the heat generated from the heating body to the inner wall portion of the constant <br/> form rollers corresponding to the portion in contact with the fixing roller and the sheet It is characterized by the fact that it is transmitted in a timely manner.

According to a second aspect of the present invention, there is provided a fixing device.
A rotatable hollow fixing roller, a heating element disposed in the fixing roller, a heat conductor for transmitting heat generated from the heating element to the fixing roller, and fixing the sheet with toner adhered thereto. Pressurizing means for contacting a part of the outer wall of the roller, wherein the fixing roller heated by the heating element via the heat conductor thermally melts the toner on the sheet in contact with the fixing roller. is, in the fixing device for fixing the toner on the sheet, the heat conducting body, be one that is composed of a plurality of heat conductors portions arranged in the extending direction of the central axis of the fixing roller, the The heat generated from the heating element is intensively transmitted to an inner wall portion of the fixing roller corresponding to a portion where the fixing roller contacts the sheet .

According to a third aspect of the present invention, there is provided a fixing device.
A rotatable hollow fixing roller, a heating element disposed in the fixing roller, a heat conductor for transmitting heat generated from the heating element to the fixing roller, and fixing the sheet with toner adhered thereto. Pressurizing means for contacting a part of the outer wall of the roller, wherein the fixing roller heated by the heating element via the heat conductor thermally melts the toner on the sheet in contact with the fixing roller. In the fixing device for fixing the toner to the sheet, the heat conductor is in sliding contact with an inner wall portion of the fixing roller corresponding to a portion where the fixing roller and the sheet are in contact with each other. The fixing roller is configured to intensively transmit heat generated from the heating element to an inner wall portion of the fixing roller corresponding to a portion in contact with a sheet, and is configured using a conductive material. Characterized in that it is grounded.

[0014]

[0015]

[0016]

[0017]

According to the fixing device of the present invention , the heat generated from the heating element is transmitted to the heat conductor. The heat transmitted to the heat conductor is intensively transmitted to an inner wall portion of the fixing roller corresponding to a portion where the fixing roller contacts the sheet. That is,
The portion of the fixing roller that contacts the sheet is intensively heated, and the heated area is reduced. Therefore,
The time required for the temperature of the fixing roller in contact with the sheet to reach a predetermined temperature can be reduced without increasing the heat generation amount of the heating element.

When the sheet is pressed against the fixing roller by the pressing means , the toner on the sheet is melted by the heat of the fixing roller. On the other hand, the temperature of the fixing roller other than the portion in contact with the sheet is lowered in accordance with the distance from the heated portion. Therefore, when the sheet separates from the heated portion with the rotation of the fixing roller, the temperature of the toner on the sheet decreases, and when the sheet separates from the fixing roller, the toner adheres to the sheet. Therefore, the toner on the sheet hardly adheres to the fixing roller, and the offset can be effectively prevented. Further, at this time, since the toner on the sheet is fixed, the adhesive force of the toner is sufficiently reduced, so that the sheet is easily separated from the fixing roller.

[0019] In particular, in the fixing device according to the first aspect of the present invention, since the heating body is in contact with the heat conductor heat generated from the heating body, and more efficient heat conductor Propagate. Further, the heat propagated to the heat conductor is more efficiently transmitted to a portion of the fixing roller where the heat conductor contacts. Therefore, the heating time of the fixing roller can be further reduced.

Further, in the fixing device according to the first aspect of the present invention, since the heat conductor has elasticity, the heat conductor is attached to the heat generator and the inner wall of the fixing roller. Make sure it touches. Therefore, the heat generated from the heating element is more reliably transmitted to the fixing roller.

[0021] In particular, according to the fixing device of the invention according to claim 2, constituted the heat conductor at a plurality of heat conductors portions arranged in the extending directions of the center axis of the fixing roller Therefore, undesired bending or distortion occurring on the inner surface of the fixing roller is absorbed by each discontinuous portion of the plurality of heat conductor portions, and each heat conductor portion is securely attached to the inner wall of the fixing roller. Can be abutted.

[0022] In particular, in the fixing device according to the invention of claim 3, when the heat conducting member slides on the inner wall of the fixing roller, resulting in static electricity. For this reason, the heat conductor is made of a conductive material and is electrically grounded. Thereby, the static electricity generated in the heat conductor can be removed. Therefore, the toner on the sheet can be prevented from adhering to the fixing roller due to the Coulomb force.

[0023]

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a laser beam printer using a fixing device according to a first embodiment of the present invention. This laser beam printer has the following configuration.

Inside the case 101, there is provided a paper feed tray 102 in which sheets are stored. In the vicinity of the paper feed tray 102, a paper feed roller 103 is provided.
And a transfer roller 105. The photosensitive drum is rotatable, and a charging brush 106 for charging the surface of the photosensitive drum 113 is provided near the photosensitive drum 113. The surface of the photosensitive drum 113 is irradiated with a laser beam from the optical unit 109 to form an electrostatic latent image. The developing device 107 forms a toner image by attaching toner to the electrostatic latent image. Transfer roller 105
Forms a predetermined electric field with the photosensitive drum 113,
It has a function of transferring the toner image on the photosensitive drum 113 to a sheet. Further, a blade 108 for scraping residual toner is provided at a position where the blade 108 contacts the photosensitive drum 113. Above the photosensitive drum 113, a fixing device 10 for fixing the upper toner on the sheet is provided. The fixing device includes a fixing roller 11 and a pressure roller 12 that presses a sheet against the fixing roller. Further, a transport roller 110 and a paper discharge roller 111 are provided above the fixing device 10. The case 101 has a discharge tray 112 from which sheets conveyed via the conveyance rollers 110 and the discharge rollers 111 are discharged.
Is provided.

The fixing device 10 will be described with reference to FIG. FIG. 2 is a cutaway perspective view of the fixing device according to the present embodiment.

The fixing roller 11 has a hollow cylindrical shape and is rotatable. In order to improve the releasability from the sheet and to prevent offset,
Teflon coated. The pressure roller 12 serving as a pressure unit is also cylindrical, and can rotate while being pressed against the fixing roller 11. An elastic member 1 such as silicon sponge or rubber is provided on the surface of the pressure roller 12.
2A is coated.

A heating element 13 is provided inside the fixing roller 11.
And a support member 15 for holding the heating element 13 and a plurality of heat conductors 14. The support member 15 is formed in a rod shape, and is fixed to a frame or the like of a laser beam printer. The heating element 13 is fixed to the support member 15. The heating element 13 is formed of a resistor having a long plate shape, and generates a high temperature when a voltage is applied. The heat conductor 14 is made of a metal plate having a high heat conductivity bent into the shape shown in FIG.
A part of the heat conductor 14 is fixed to the heating element 13. The bent portion of the heat conductor 14 is near the nip portion 16 of the fixing roller 11 (the contact portion between the fixing roller 11 and the pressure roller 12), and is in contact with the inner wall of the fixing roller 11. When the fixing roller 11 rotates, the heat conductor 14 slides on the inner wall of the fixing roller 11.

The laser beam printer having such a configuration operates as described below. That is, the sheets stored in the paper feed tray 102 are
By 3, the sheet is conveyed to the nip between the photosensitive drum 113 and the transfer roller 105. After the toner is transferred at the nip portion, the sheet is conveyed to the fixing device 10. The sheet is heated by the fixing roller 11 while being sandwiched between the fixing roller 11 and the pressure roller 12. Then, the toner on the sheet is melted by heat and fixed on the sheet surface. The sheet on which the toner is fixed by the fixing device 10 passes through a discharge roller 112 via a conveyance roller 110 and a discharge roller 111.
Is discharged.

Next, the operation of the fixing device 10 will be described in detail. When the power of the laser beam printer is turned on, a predetermined voltage is applied to the heating element 13, and the heating element 13 generates high heat. The heat generated from the heating element 13 propagates throughout the heat conductor 14. Since the thermal conductivity of the thermal conductor 14 is high, the temperature of the portion of the thermal conductor 14 that abuts on the fixing roller 11 becomes substantially equal to the temperature of the heating element 13 in a short time.
Since the fixing roller 11 is thin, its heat capacity is relatively small. Therefore, the fixing roller 11 with which the heat conductor 14 contacts
, The nip portion 16 of the fixing roller 11
Are heated in a short time. Therefore, the heating element 14
After the voltage is applied to the nip portion 16 of the fixing roller 11,
Temperature suitable for fixing (150-200 ° C)
Can be shortened.

Since the heat conductor 14 is in contact only with the nip 16 of the fixing roller 11, the temperature of the fixing roller 11 other than the nip 16 is lower than the temperature of the nip 16. I have. When the fixing roller 11 rotates, the portion of the fixing roller 11 that has been in contact with the heat conductor 14 moves away from the heat conductor 14. Since the heat capacity of the fixing roller 11 is small, the temperature of the portion of the fixing roller 11 away from the nip portion 16 is reduced by heat radiation.

The sheet conveyed to the fixing device 10 is nipped at a contact portion between the fixing roller 11 and the pressure roller 12, that is, a nip portion 16. Since the pressure roller 12 is in pressure contact with the fixing roller 11, the elastic member on the surface of the pressure roller 12 is deformed. Then, the contact portion between the fixing roller 11 and the pressure roller 12, that is, the area of the nip portion 16 is increased. The sheet having flexibility is the fixing roller 1
It contacts not only the nip portion 16 of one but also its periphery.
The toner on the sheet receives heat from the nip portion 16 of the fixing roller 11 and is melted by heat. With the rotation of the fixing roller 11, the portion on the sheet where the toner is thermally melted is conveyed from the nip 16 of the fixing roller 11 to the vicinity of the nip 16. At this time, the sheet is in contact with the peripheral portion of the nip portion 16 of the fixing roller 11. Since the temperature of this portion is lowered, the temperature of the heat-melted toner is lowered, and the toner is fixed on the sheet. Therefore, the toner that has been melted no longer adheres to the periphery of the nip portion 16 of the fixing roller 11, so that the so-called offset phenomenon can be prevented.

Further, when the fixing roller 11 rotates, the sheet tends to peel from the vicinity of the nip portion 16 of the fixing roller 11. At this time, since the toner on the sheet has already been fixed, the adhesive force of the toner has been sufficiently reduced. Therefore, the sheet is easily peeled off from the fixing roller 11, and the sheet is not wrapped around the fixing roller 11. For this reason, jamming of the sheet can be prevented.

As described above, according to the fixing device of the present embodiment, the time required for heating the fixing roller 11 can be reduced without increasing the amount of heat generated by the heating element 13.
For this reason, it is possible to prevent an increase in the temperature inside a device such as a laser beam printer including the fixing device 10 according to the present embodiment. In addition, an increase in current consumption of the heating element 13 can be suppressed. Further, when the sheet is separated from the fixing roller, the toner on the sheet is fixed.
1, and the offset phenomenon can be prevented.
At this time, since the adhesive force of the toner on the sheet is also reduced, the sheet is easily peeled off from the fixing roller, and jamming can be prevented.

FIG. 3 is a sectional view showing a fixing device according to a second embodiment of the present invention. In this figure, FIG.
FIG. 2 is a cross-sectional view of the fixing device according to the present exemplary embodiment, which is cut perpendicular to the center axis of the fixing roller. FIG. 3B is a cross-sectional view of the fixing device according to the present exemplary embodiment, cut along a central axis of the fixing roller.

The fixing device according to this embodiment includes a heat conductor 34.
The configuration is substantially the same as that of the fixing device 10 according to the first embodiment except for the shape of the fixing device. That is, the two flat frames 37 (only one is shown in FIG. 2B) are held in a case of a laser beam printer or the like so as to face each other. Each frame 37 is provided with a bearing 311 and a bearing 321. The bearing 311 holds the fixing roller 31 so as to be rotatable. The pressure roller 32 is held by the bearing 321 so as to be similarly rotatable. The pressure roller 22 is configured to rotate while being pressed against the fixing roller 21.

A support member 35 is provided inside the fixing roller 32.
, A heating element 33 and a heat conductor 34.
Since the heating element 33 and the supporting member 35 are configured in substantially the same manner as the heating element 13 and the supporting member 15 according to the first embodiment, description thereof will be omitted. The heating element 33
Terminals 331 are provided at both ends of the terminal 331.
, A predetermined voltage is applied to the heating element 33. The heat conductor 34 is formed in a hollow cylindrical shape, and both ends thereof are fixed to the support member 35 using screws 341. The operation and effect of the fixing device according to the second embodiment are the same as the operation and effect of the fixing device 10 according to the first embodiment, and thus description thereof will be omitted.

FIG. 4 is a sectional view showing a fixing device according to a third embodiment of the present invention. In this figure, FIG.
FIG. 2 is a cross-sectional view of the fixing device according to the present exemplary embodiment, which is cut perpendicular to the center axis of the fixing roller. FIG. 4B is a cross-sectional view of the fixing device according to the present embodiment cut along a central axis of the fixing roller.

The heat conductor 44 in the present fixing device is different from the heat conductor 34 in that it has no hollow portion inside. The fixing device according to the present embodiment includes a heat conductor 4
The configuration is the same as that of the fixing device according to the second embodiment except for No. 4, and thus the same reference numerals are given and the description is omitted. In the fixing devices according to the fourth to ninth embodiments described below, the same components as those of the fixing device according to the second embodiment described above have the same configuration as the fixing device according to the second embodiment. The same reference numerals are given to the members to be described, and the description of the members will be omitted.

FIG. 5 is a sectional view showing a fixing device according to a fourth embodiment of the present invention. In this figure, FIG.
FIG. 2 is a cross-sectional view of the fixing device according to the present exemplary embodiment, which is cut perpendicular to the center axis of the fixing roller. FIG. 5B is a cross-sectional view of the fixing device according to the present embodiment, which is cut along the center axis of the fixing roller.

The heat conductor 54 in the present fixing device is formed in a cylindrical shape, and both ends thereof are held by a bearing 541 so as to be rotatable. This bearing 541 is fixed to the support member 35. In FIG. 5, the heat conductor 5
The lower part of 4 is in contact with the inner wall of the fixing roller 31, and the heat conductor 54 rotates in the opposite direction as the fixing roller 31 rotates. The upper portion of the heat conductor 54 slides while being in contact with the heating element 33.

FIG. 6 is a sectional view showing a fixing device according to a fifth embodiment of the present invention. In this figure, FIG.
FIG. 2 is a cross-sectional view of the fixing device according to the present exemplary embodiment, which is cut perpendicular to the center axis of the fixing roller. FIG. 6B is a cross-sectional view of the fixing device according to the present embodiment, which is cut along the center axis of the fixing roller.

The heat conductor 64 in the present fixing device has a plurality of notches and is formed in a comb shape. The ends of the cut-out portions of the heat conductor 64 are bent, and are pressed against the inner wall of the fixing roller 31. When the fixing roller 31 rotates, each bent portion of the heat conductor slides on the inner wall of the fixing roller 31. The heat conductor 64 is fixed to the support member 35 using screws 641.

Assuming that the thermal conductor 64 is not provided with a cut, the distance that the thermal conductor 64 continuously contacts the inner wall of the fixing roller 31 increases. For this reason, when the processing accuracy of the heat conductor 64 is not sufficient,
It is difficult to uniformly contact the fixing roller 31 with the fixing roller 31.
Therefore, a notch is formed in the heat conductor 64 so that the heat conductor 64 is notched.
Is divided into contact with the inner wall of the fixing roller 31 so that the divided portion of the heat conductor 64 can easily contact the inner wall of the fixing roller 31 uniformly. Accordingly, heat is reliably transmitted from the heat conductor 64 to the fixing roller 31, and the time required for heating the fixing roller 31 can be further reduced. Further, when manufacturing the heat conductor 64, there is an advantage that the manufacturing becomes easy because high processing accuracy is not required.

FIG. 7 is a sectional view showing a fixing device according to a sixth embodiment of the present invention. In this figure, FIG.
FIG. 2 is a cross-sectional view of the fixing device according to the present exemplary embodiment, which is cut perpendicular to the center axis of the fixing roller. FIG. 7B is a cross-sectional view of the fixing device according to the present embodiment, which is cut along the center axis of the fixing roller.

The heat conductor 74 according to the present fixing device comprises a rod 74 made of a large number of needle-like heat conductive materials on a shaft 74A.
B is provided. The rod-shaped shaft 74A is rotatably held by a bearing 741. The brush 74B is in contact with the inner wall of the fixing roller 31, and as the fixing roller 31 rotates, the heat conductor 74 rotates in the opposite direction. Then, the brush 74B slides while contacting the heating element 33. The heat conductor 74 according to this embodiment has an advantage that it reliably contacts the inner wall of the fixing roller 31.

FIG. 8 is a sectional view showing a fixing device according to a seventh embodiment of the present invention. In this figure, FIG.
FIG. 2 is a cross-sectional view of the fixing device according to the present exemplary embodiment, which is cut perpendicular to the center axis of the fixing roller. FIG. 8B is a cross-sectional view of the fixing device according to the present embodiment, which is cut along the center axis of the fixing roller.

The heat conductor 84 of the fixing device 80 includes a plate-shaped heat conductive material 84A, a brush 84B made of a plurality of needle-shaped heat conductive materials provided on the heat conductive material 84A,
Is configured. The heat conductive material 84A is the heating element 3
3 so as to be pressed against the support member 35.
The end of the brush 84B is slidably in contact with the fixing roller 31.

FIG. 9 is a sectional view showing a fixing device according to an eighth embodiment of the present invention. In this figure, FIG.
FIG. 2 is a cross-sectional view of the fixing device according to the present exemplary embodiment, which is cut perpendicular to the center axis of the fixing roller. FIG. 9B is a cross-sectional view of the fixing device according to the present embodiment, which is cut along the center axis of the fixing roller.

The heating element 93 according to the fixing device is constituted by using a rod-shaped halogen lamp. This heating element is fixed to the frame 371. The heat conductor 94 is configured to include a hollow cylindrical heat conductive material 94 and a plurality of needle-shaped brushes 94B formed of a needle-shaped heat conductive material. The heat conductive material 94A is
And the heating element 93 is provided in the hollow portion of the heat conductive material 94A. The brush 94B slidably contacts the inner wall of the fixing roller 31.

FIG. 10 is a sectional view showing a fixing device according to a ninth embodiment of the present invention. FIG. 10A is a cross-sectional view of the fixing device according to the present embodiment, which is cut perpendicular to the center axis of the fixing roller. FIG.
FIG. 0B is a cross-sectional view of the fixing device according to the present embodiment cut along the central axis of the fixing roller.

The heat conductor 104 is made of a rod-shaped heat conductive material 10.
4A and a brush 104B made of a plurality of needle-like heat conductive materials provided on the heat conductive material 104A. The heat conductive material 104A is rotatably held by the bearing 372.

FIG. 11 is a sectional view showing a fixing device according to a ninth embodiment of the present invention. FIG. 11A is a cross-sectional view of the fixing device according to the present embodiment, which is cut perpendicular to the center axis of the fixing roller. FIG.
FIG. 1B is a cross-sectional view of the fixing device according to the present embodiment cut along a central axis of the fixing roller.

The heat conductor 114 is made of a plate-like heat conductive material bent into a predetermined shape shown in FIG. The heat conductor 114 is fixed to the frame 371. The heat conductor 114 is not in contact with the heating element 93 formed of a halogen lamp, and heat generated from the heating element 114 is transmitted to the heat conductor 114 by radiation. The heat conductor 114 is in pressure contact with the inner wall of the fixing roller 31 and has a slidable configuration.

The fixing devices according to the second to ninth embodiments described above reduce the time required for heating the fixing roller and reduce the offset phenomenon, similarly to the fixing device according to the first embodiment. Preventing the sheet from peeling off from the fixing roller. In addition, the above-mentioned first embodiment-
In the fixing device according to the ninth embodiment, the heat conductor may be made of a conductive material and the heat conductor may be grounded. In this case, in order to prevent the heating element from being grounded via the thermal conductor, it is desirable to electrically insulate the heating element from the thermal conductor. With such a configuration, static electricity generated when the heat conductor slides on the fixing roller can be effectively removed, and thus toner can be prevented from adhering to the fixing roller due to Coulomb force.

[0057]

As described above, according to the present invention, in the fixing device, the time required for heating the fixing roller can be reduced, the offset phenomenon can be prevented, and the sheet can be easily separated from the fixing roller. .

[Brief description of the drawings]

FIG. 1 is a sectional view of a laser beam printer using a fixing device according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of the fixing device according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a fixing device according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a fixing device according to a third embodiment of the present invention.

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

FIG. 6 is a sectional view showing a fixing device according to a fifth embodiment of the present invention.

FIG. 7 is a sectional view showing a fixing device according to a sixth embodiment of the present invention.

FIG. 8 is a sectional view showing a fixing device according to a seventh embodiment of the present invention.

FIG. 9 is a sectional view showing a fixing device according to an eighth embodiment of the present invention.

FIG. 10 is a sectional view showing a fixing device according to a ninth embodiment of the present invention.

FIG. 11 is a sectional view showing a fixing device according to a tenth embodiment of the present invention.

FIG. 12 is a cross-sectional view showing a part of a conventional fixing device in a cutaway manner.

[Explanation of symbols]

11, 31 Fixing roller 12, 32 Pressure roller (Pressing means) 13, 33, 93 Heating element 14, 34, 44, 54, 64, 74, 84, 94, 1
04,114 Thermal conductor 15,35 Support member

──────────────────────────────────────────────────続 き Continuing from the front page Examiner Takasuke Takahashi Yusuke Hashi (56) References JP-A-4-114184 (JP, A) JP-A-4-129166 (JP, U) (58) Fields investigated (Int. Cl. ^7, DB name) G03G 13/20 G03G 15/20

Claims (3)

(57) [Claims] A rotatable hollow fixing roller; a heating element disposed in the fixing roller; a heat conductor for transmitting heat generated from the heating element to the fixing roller; Pressurizing means for bringing the formed sheet into contact with a part of the outer wall of the fixing roller, wherein the fixing roller heated by the heating element via the heat conductor is provided on the sheet in contact with the fixing roller. A fixing device for dissolving the toner by heat and fixing the toner to the sheet, wherein the heat conductor has elasticity, and
Inner wall part of the fixing roller corresponding to the part that contacts the sheet
And press them against the heating element,
Fixing apparatus characterized by transmitting the heat generated from the heating body to the inner wall portion of the fixing roller corresponding to the portion in contact with the fixing roller and the sheet intensively. 2. A rotatable hollow fixing roller, a heating element disposed in the fixing roller, a heat conductor transmitting heat generated from the heating element to the fixing roller, and adhesion of toner. Pressurizing means for bringing the formed sheet into contact with a part of the outer wall of the fixing roller, wherein the fixing roller heated by the heating element via the heat conductor is provided on the sheet in contact with the fixing roller. the toner was thermally dissolved, a fixing device for fixing the toner on the sheet, the heat conducting body, which is composed of a plurality of heat conductors portions arranged in the extending direction of the central axis of the fixing roller a is a fixing apparatus characterized by transmitting the heat generated from the heating body to the inner wall portion of the fixing roller corresponding to the portion in contact with the fixing roller and the sheet intensively. 3. A rotatable hollow fixing roller, a heating element disposed in the fixing roller, a heat conductor transmitting heat generated from the heating element to the fixing roller, and adhesion of toner. Pressurizing means for bringing the formed sheet into contact with a part of the outer wall of the fixing roller, wherein the fixing roller heated by the heating element via the heat conductor is provided on the sheet in contact with the fixing roller. In the fixing device for thermally dissolving the toner of the above, the toner is fixed to the sheet, the heat conductor is in sliding contact with the inner wall portion of the fixing roller corresponding to the portion where the fixing roller contacts the sheet, A material that conducts heat intensively from the heating element to an inner wall portion of the fixing roller corresponding to a portion where the fixing roller contacts the sheet, and uses a conductive material. Configured Te, a fixing device, wherein electrically be grounded.