JPH07319319A - Fixing roller device - Google Patents

Abstract

PURPOSE:To provide a fixing roller device capable of eliminating the futile consumption on of power and efficiently making use of the power by setting a contact width in a cylindrical direction where a feeder electrode comes into slidable contact with a connection electrode equal to a contact width in a circumferential direction where a resistance heating element press-contacts with a pressure roller. CONSTITUTION:In a fixing roller 1, the resistance heating element 3 is formed in a region on the outer periphery of a cylindrical substrate coming into contact with the pressure roller 6 and the connection electrodes 4 located on both ends of the resistance heating element 3 and divided in the circumferential direction Y is formed as well. The power is supplied to the feeder electrodes 5 coming into slidable contact with the connection electrodes 4 of the fixing roller 1, so that the resistance heating element 3 can generate heat. The contact width L in the circumferential direction Y where the feeder electrode 5 comes into slidable contact with the connection electrode 4 is set equal to the contact width in the circumferential direction Y where the resistance treating element 3 press-contacts with the pressure roller 6. Thus, the power is supplied only to the region of the resistance heating element 3 corresponding to a fixing region at the time of actually fixing, to heat the region. Thus, the futile use of the power is eliminated and the power can be efficiently used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing roller device having a heater on a fixing roller.

[0002]

2. Description of the Related Art Conventionally, as a fixing roller having a built-in heater, there is a type in which the heater is housed in a space inside the roller or the heater is embedded near the surface layer of the roller. In this case, in order to keep the roller surface temperature within a certain temperature range, the roller surface temperature is detected to control the electric power supplied to the heater, or to shorten the time until the roller surface temperature reaches a fixable temperature. After the power is turned on, a large current is applied to the device and then the temperature is controlled to approach a predetermined temperature. However, such a method of faithfully controlling the roller surface temperature by adjusting the applied voltage and the like is extremely complicated. Further, in the fixing roller in which the heater is embedded, the roller is composed of a relatively thin cylindrical body, and its heat capacity is small. Therefore, the area other than the fixing area simply dissipates heat to the outside, and the heat utilization efficiency is poor.

Therefore, in order to deal with such a problem, the following method has been conventionally used. First, as a first conventional example, JP-A-55-1686
There is one disclosed in Japanese Patent No. 3 publication. As shown in FIG. 5, the resistance heating element 3 is formed on the outer surface of the cylindrical support 2, and the divided electrodes 4 (connection electrodes to be described later) divided in the circumferential direction Y are provided at both ends of the resistance heating element 3. (Corresponding to the above), the fixing roller 1 is configured. Then, by supplying electric power from the power feeding electrode 5 which is in sliding contact with the divided electrode 4, as shown in FIG. 6, the inside of the resistance heating element 3 connected to the region (electrode resistance Ro) with which the power feeding electrode 5 contacts. Resistance Ra (inter-electrode resistance) is selected to generate heat. In this way, the temperature of the area required for fixing is raised to perform stable fixing.

As a second conventional example, Japanese Patent Laid-Open No. 62-279.
Some are disclosed in Japanese Patent No. 377. As shown in FIG. 7, the resistance heating element 3 is linearly divided into a plurality of pieces in the circumferential direction Y, and the feeding electrode 5 is also divided into a plurality of pieces in the circumferential direction Y. Has been done. in this case,
By supplying a predetermined electric power from each of the power supply electrodes 5, each linear resistance Rb of the resistance heating element 3 generates heat corresponding to the electric power value as shown in FIG. The temperature is controlled efficiently.

[0005]

In the case of the first conventional example,
The electric current flows in the axial direction X of the line connecting the divided electrodes 4, and the heat generation of the resistance heating element 3 is generated along the region (the region of the resistance Ra) in which the current easily passes. As a result, as shown in FIG. 9, the temperature distribution on the heat generating surface has a certain degree of spread in the circumferential direction Y because the temperature region slightly flows around the axial direction X in which the current flows.
Uniform heat generation is not always obtained in the axial direction X. In addition, in this example, the energization area is approximately 1/1 of the entire circumference.
However, the heat generation area directly involved in the fixing is only the area in contact with the pressure roller (not shown), and therefore, the wasteful area not actually involved in the fixing is also generated. Further labor saving of electric power is desired.

In the case of the second conventional example, since the current flows independently in each of the divided linear resistance heating elements 3, as shown in FIG. 10, the temperature in the circumferential direction Y on the heating surface is increased. It causes uneven distribution. Also, in this example, the cylindrical support 2
There is a region with the resistance heating element 3 on the top and a region without the resistance heating element 3, and in order to maintain uniformity when contacting the pressure roller, other members are embedded between the members of the resistance heating element 3 to flatten or add. Although the material on the pressure roller side is made softer to improve the contact, there are still problems with the fixability and manufacturing. Further, here, it is possible to select the operation of the power supply electrode 5 divided into a plurality of parts, but normally, the fixing speed of the apparatus is constant, and the amount of toner or the like supplied varies depending on the original. Because it is different, it is difficult to perform detailed control.
Moreover, the mechanism for causing the power feeding electrode 5 to perform such control becomes complicated, and the structure cannot be simplified.

[0007]

According to a first aspect of the present invention, there is provided a resistance heating element formed in a region of an outer peripheral surface of a cylindrical support which is in contact with a pressure roller, and circles located at both ends of the resistance heating element. A fixing roller having a connecting electrode formed by dividing the fixing roller in the circumferential direction is provided, and power is supplied to a power supply electrode that is in sliding contact with the connecting electrode of the fixing roller, thereby causing the resistance heating element to generate heat and fixing. In the fixing roller device to be performed, the contact width in the circumferential direction of the power supply electrode in sliding contact with the connection electrode is set to be equal to the contact width in the circumferential direction of the resistance heating element in pressure contact with the pressure roller.

According to a second aspect of the present invention, in the first aspect of the present invention, the connection electrodes arranged opposite to each other at both ends of the resistance heating element are staggered so that the axes of the connection electrodes do not overlap. did.

According to a third aspect of the present invention, in the first aspect of the present invention, the position of the connection electrode which is in sliding contact with the power supply electrode is arranged on the opposite side of the nip position where the pressure roller contacts the resistance heating element. Let

According to a fourth aspect of the present invention, in the first aspect of the invention, the contact width in the circumferential direction of the feed electrode that makes sliding contact with the connection electrode is formed so as to extend in the roller forward direction.

According to a fifth aspect of the invention, in the first aspect of the invention, the contact width in the circumferential direction of the power supply electrode, which makes sliding contact with the connection electrode, is formed to extend in the roller rotation rear direction.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the contact width in the circumferential direction, which is in sliding contact with the connection electrode of the power supply electrode, is formed by extending the roller rotation forward and backward.

[0013]

According to the first aspect of the present invention, the connecting electrode is supplied with electric power corresponding to the contact width in the circumferential direction in sliding contact with the feeding electrode, and the contact electrode is supplied with the electric power corresponding to the contact width. The area of the resistance heating element is heated. The area of the heated resistance heating element is equal to the area directly involved in fixing, that is, the contact width in the circumferential direction in which the pressure roller is in pressure contact. As a result, since only the area of the resistance heating element corresponding to the fixing area is heated when the fixing is actually performed, it is possible to eliminate unnecessary power consumption to the area not directly involved in the fixing. . Further, this makes it possible to reduce the response speed from the power supply to the resistance heating element to the actual heat generation.

According to the second aspect of the present invention, since the connection electrodes are arranged so as to be staggered so as not to overlap on the same axis, temperature spread occurs in the axial direction inside the resistance heating element, and It is possible to obtain a temperature distribution with little deviation.

According to the third aspect of the present invention, the position of the connecting electrode which is in sliding contact with the power feeding electrode is arranged on the opposite side of the nip position where the pressure roller contacts the resistance heating element. It is possible to make the installation space of the wiring portion related thereto extremely wide.

According to the fourth aspect of the present invention, by extending the circumferential contact width of the power supply electrode in the roller rotation front direction, the roller rotation not directly involved in the fixing when the fixing is actually performed. Since the area of the resistance heating element in the forward direction is also heated, radiant heat is applied to the transfer paper immediately after fixing by the heat generation effect in the area other than the contact portion, and the temperature of the paper can be further increased.

According to the fifth aspect of the present invention, by extending the circumferential contact width of the power supply electrode in the roller rotation rearward direction, the roller rotation not directly involved in the fixing when the fixing is actually performed. Since the area of the resistance heating element in the rearward direction is also heated, radiant heat is applied to the transfer paper immediately before fixing due to the heat generation effect in the area other than the contact portion, so that the temperature of the paper can be further increased.

According to the sixth aspect of the invention, the contact width in the circumferential direction of the power feeding electrode is extended in the front and rear directions of the roller rotation, so that it is not directly involved in the fixing when the fixing is actually performed. Since the area of the resistance heating element in the front and rear directions of the roller rotation is also heated, radiant heat is applied to the transfer paper immediately before and immediately after fixing by the heat generating effect in the area other than the contact portion, so that the temperature of the paper is further increased. It will be possible.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention described in claim 1 will be described with reference to FIGS. The same reference numerals are used for the same names as in the conventional example. As shown in FIG. 1, in the fixing roller 1, a resistance heating element 3 is formed in a region of an outer peripheral surface of a cylindrical support 2 (which is supported by a bearing 2a in the cylinder) that contacts the pressure roller 6. Connection electrodes 4 are formed at both ends of the resistance heating element 3 and divided in the circumferential direction Y. By supplying electric power to the power supply electrode 5 which is in sliding contact with the connection electrode 4 of the fixing roller 1, the resistance heating element 3 can generate heat. In the present embodiment, the contact width L in the circumferential direction Y in which the power supply electrode 5 slides in contact with the connection electrode 4 is defined as the contact width W in the circumferential direction Y in which the resistance heating element 3 is in pressure contact with the pressure roller 6. Set equal.

In such a structure, the resistance heating element 3 of the fixing roller 1 is arranged so that the contact width L of the power feeding electrode 5 is equal to the pressure roller 6
The reason why the contact width W is set to be equal to the contact width W in the circumferential direction Y that is pressed against will be described with reference to FIGS. Figure 2 (a)
Indicates that the fixing roller 1 and the pressure roller 6 are not pressed. Now, at the time of fixing from this state, as shown in FIG. 2B, pressure P is applied, and the resistance heating element 3 on the outer peripheral surface of the fixing roller 1 is elastic body provided on the outer peripheral surface of the pressure roller 6. When contacting with 7 (for example, silicone rubber), a pressure distribution 8 as shown in FIG. 2D corresponding to the contact width Wo in the circumferential direction Y is obtained. In this case, the contact width Wo is the rotation axis O
Since the pressure distribution 8 is symmetrical with respect to the center, the pressure distribution 8 is also symmetrical. Next, as shown in FIG. 2C, when the transfer paper 9 is guided from the A side to the B side and fixed, the fixing roller 1
When is rotated in the direction of the arrow and the pressure roller 6 is rotated together, the elastic body 7 is bulged and deformed to one side, and the contact width Wo is changed to the contact width W. Since this contact width W is asymmetric with respect to the rotation axis O, an asymmetric pressure distribution 10 as shown in FIG. Therefore, only the area of the resistance heating element 3 corresponding to the contact width W thus deformed by contact is heated. This can be achieved by making the contact width L in the circumferential direction Y of the connection electrode 4 that causes the resistance heating element 3 to generate heat, that is, the power supply electrode 5 in sliding contact with this connection electrode 4, equal to the contact width W. it can. However, in the actual contact state, the contact state changes depending on the roller diameter of the pressure roller 6, the elastic modulus of the elastic body 7 (hardness of rubber or the like), the applied pressure, etc. Therefore, the contact width L is set according to those situations. To do so. As described above, the contact width L of the power feeding electrode 5 is
By making the contact width W of the resistance heating element 3 of the fixing roller 1 equal, it is possible to supply power to heat only the area of the resistance heating element 3 corresponding to the fixing area during actual fixing. As a result, wasteful consumption of electric power can be eliminated and efficient electric power can be used. Further, by configuring the contact width to be short as described above, the response speed from the power supply to the resistance heating element 3 to the actual heat generation can be increased.

Next, an embodiment of the invention described in claim 2 will be described with reference to FIG. The same reference numerals are used for the same names as those in the first aspect of the invention. In this embodiment, the connection electrodes 4 are arranged opposite to each other at both ends of the resistance heating element 3.
Are arranged in a staggered manner so that the axes 11 of the respective connection electrodes 4 do not overlap. In such a configuration, by arranging the connection electrodes 4 in a staggered manner, the temperature spreads (disperses) in the axial direction X inside the resistance heating element 3 as shown in the hatched area in FIG.
Occurs. As a result, it is possible to obtain a uniform temperature distribution with less deviation over the entire heating area of the resistance heating element 3.

Next, an embodiment of the invention described in claim 3 will be described with reference to FIG. The same reference numerals are used for the same names as those of the inventions described in claims 1 and 2. In the present embodiment, the position of the connection electrode 4 which is in sliding contact with the power supply electrode 5 is arranged on the opposite side of the nip position where the pressure roller 6 contacts the resistance heating element 3. In this case, since the connection electrode 4 to which electric power is supplied from the power supply electrode 5 is located on the opposite side of the area of the resistance heating element 3 which is the heat generation area during fixing, the connection electrode 4 is connected to the resistance heating element 3. Until then, the electrode portion 4a has a twisted shape.

In such a structure, by disposing the connecting electrode 4 on the outer peripheral surface of the cylindrical support 2 on the side opposite to the pressure roller 6, the power supplying electrode 5 slidingly contacting the connecting electrode 4 and the connecting electrode 4 are provided. It is possible to make the installation space of the related wiring portion (not shown) extremely wide. This facilitates the design and improves the assemblability.

Next, an embodiment of the invention described in claims 4, 5 and 6 will be described with reference to FIG. The same reference numerals are used for the same names as the inventions described in claims 1, 2 and 3. In this embodiment, the contact width L in the circumferential direction Y, which is in sliding contact with the connection electrode 4 of the power supply electrode 5, is formed by extending the roller rotation forward and backward directions. In addition to this, the contact width L is only in the roller rotation forward direction, or
It may be formed by extending only in the roller rotation rear direction.

In such a configuration, in FIG. 4, the roller rotation forward direction (B side) and the roller rotation backward direction (A
1 shows an example of a heat generation state on the contact surface between the pressure roller 6 and the fixing roller 1 when the contact width L of the power feeding electrode 5 is formed on the side). This makes it possible to heat the regions of the resistance heating element 3 in the roller rotation forward direction B and the roller rotation backward direction A that are not directly involved in the fixing at the time of actual fixing, and the radiation in the regions other than the contact portion can be heated. Radiant heat 1 is applied to the transfer paper 9 immediately before and immediately after fixing by the action.
2 can be given to further increase the temperature of the paper.
Therefore, the effect of the radiant heat 12 can further promote the fixing effect. Even when the contact width L of the power supply electrode 5 is extended only in the roller rotation forward direction B or only in the roller rotation backward direction A, the fixing by the radiant heat 12 can be promoted.

[0026]

According to the first aspect of the present invention, the resistance heating element is formed in the region of the outer peripheral surface of the cylindrical support which contacts the pressure roller, and the resistance heating element is located at both ends and divided in the circumferential direction. A fixing roller having a connection electrode formed by
In a fixing roller device that supplies electric power to a power supply electrode that is in sliding contact with the connection electrode of the fixing roller to heat the resistance heating element to perform fixing, a circle that is in sliding contact with the connection electrode of the power supply electrode. Since the contact width in the circumferential direction is set equal to the contact width in the circumferential direction in which the resistance heating element is in pressure contact with the pressure roller, the resistance heating element corresponding to the fixing area during actual fixing is performed. It is possible to supply electric power only to the area to heat the area, and thereby to prevent wasteful consumption of electric power and to provide a fixing roller device capable of efficiently using electric power.

According to a second aspect of the present invention, in the first aspect of the present invention, the connection electrodes arranged opposite to each other at both ends of the resistance heating element are staggered so that the axes of the connection electrodes do not overlap. Therefore, it is possible to obtain a temperature distribution in the axial direction inside the resistance heating element, and thereby to obtain a uniform temperature distribution with less deviation in the heating area.

According to a third aspect of the present invention, in the first aspect of the present invention, the position of the connection electrode which is in sliding contact with the power supply electrode is arranged on the side opposite to the nip position where the pressure roller contacts the resistance heating element. As a result, the space for disposing the power supply electrode and the wiring portion related thereto can be made extremely wide, which facilitates the design and improves the assembling property.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the contact width in the circumferential direction of the feed electrode, which is in sliding contact with the connection electrode, is formed by extending in the roller rotation forward direction. Radiant heat can be applied to the transfer paper immediately after fixing by the heat generation effect in the area other than the above area to further raise the temperature of the paper, whereby the fixing effect can be further promoted.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the contact width in the circumferential direction of the feed electrode, which makes sliding contact with the connection electrode, is formed by extending the roller rotation rearward direction. Radiation heat can be applied to the transfer paper immediately before fixing by the heat generation effect in the other area, and the temperature of the paper can be further raised, whereby the fixing effect can be further promoted.

According to a sixth aspect of the present invention, in the first aspect of the invention, the circumferential contact width of the feed electrode that makes sliding contact with the connecting electrode is formed by extending the roller in the front and rear directions. Due to the heat generation in the area other than the contact area,
Radiant heat can be applied to the transfer paper immediately before and immediately after fixing to further raise the temperature of the transfer paper, whereby the fixing effect can be further promoted.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the invention described in claims 1 and 3. FIG.

2A to 2C are side views showing a pressure state of a roller, FIG. 2D is a schematic view showing a pressure distribution state with respect to FIG. 2B, and FIG. 2E is a pressure distribution state with respect to FIG. It is a schematic diagram which shows.

FIG. 3 is a front view showing an embodiment of the invention described in claim 2.

FIG. 4 is a side view showing an embodiment of the invention described in claims 4, 5, and 6.

FIG. 5 is a perspective view showing a first conventional example.

FIG. 6 is a front view schematically showing a heat generation state inside a resistance heating element.

FIG. 7 is a perspective view showing a second conventional example.

FIG. 8 is a front view schematically showing a heat generation state inside a resistance heating element.

FIG. 9 is a schematic diagram showing a temperature distribution of a first conventional example.

FIG. 10 is a schematic diagram showing a temperature distribution of a second conventional example.

[Explanation of symbols]

 1 Fixing Roller 2 Cylindrical Support 3 Resistance Heating Element 4 Connection Electrode 5 Power Supply Electrode 6 Pressure Roller 11 Axis Y Circumferential Direction L, W Contact Width

Claims (6)

[Claims] 1. A resistance heating element formed in a region of an outer peripheral surface of a cylindrical support which is in contact with a pressure roller, and connection electrodes formed at both ends of the resistance heating element and divided in a circumferential direction. In the fixing roller device, wherein a fixing roller having a fixing roller is provided, and electric power is supplied to a power supply electrode that is in sliding contact with the connection electrode of the fixing roller to heat the resistance heating element to perform fixing, the connection of the power supply electrode is performed. A fixing roller device, wherein a contact width in a circumferential direction in which the resistance heating element is in sliding contact with the electrode is set to be equal to a contact width in a circumferential direction in which the resistance heating element is in pressure contact with the pressure roller. 2. The fixing roller device according to claim 1, wherein the connection electrodes arranged opposite to each other at both ends of the resistance heating element are arranged so as to be staggered so that axes of the respective connection electrodes do not overlap with each other. . 3. The fixing roller according to claim 1, wherein the position of the connection electrode which is in sliding contact with the power supply electrode is arranged on the opposite side of the nip position where the pressure roller contacts the resistance heating element. apparatus. 4. The fixing roller device according to claim 1, wherein a contact width in a circumferential direction which is in sliding contact with the connection electrode of the power feeding electrode is formed to extend in a roller rotation forward direction. 5. The fixing roller device according to claim 1, wherein a contact width in a circumferential direction which is in sliding contact with the connection electrode of the power feeding electrode is extended in a roller rotation rear direction. 6. The fixing roller device according to claim 1, wherein a contact width in a circumferential direction which is in sliding contact with the connection electrode of the power feeding electrode is formed by extending the roller rotation forward and backward directions.