JP2001166623A - Fixing roller and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing roller capable of increasing the strength and also shortening the rise time, and to provide a fixing roller manufacturing method. SOLUTION: Plural longitudinal ribs 12 extending in parallel to the shaft of a fixing roller 10 are arranged on the inner surface of a roller core bar 11. Besides ring circumferential ribs 13 are provided on the inner surface of the roller core bar 11 so as to cross the longitudinal ribs 12. By arranging the crossed rib constituted of the longitudinal rib 12 and the circumferential rib 13 at the inner surface of the roller, thus the roller strength is drastically increased, the core bar 11 is made thin in thickness and the rise time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat roller of a fixing device mounted on an image forming apparatus such as a copying machine, a printer, a facsimile and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, a facsimile or the like using an electrophotographic system, a transfer paper,
A heat fixing device is widely used as a fixing device for fixing an unfixed image (toner image) transferred to a recording material (hereinafter, referred to as a sheet) such as an OHP film on a sheet. As the heat fixing device, a heat roller type is often used in which a pressure roller is pressed against a heated fixing roller, and the toner is heated and melted while nipping and transporting the sheet between both rollers to fix an unfixed toner image. ing.

Conventionally, in a fixing device of a heat roller type,
Most of the fixing rollers have a halogen lamp or the like as a heater and heat the fixing roller with the halogen lamp.

However, such a heating method using a heater causes the fixing roller to reach a required temperature (generally about 180 ° C.).
Since the time required for heating is long and the loss of the heater itself is large, attention is now being paid to environmental issues, so that a fixing device with high efficiency and a short rise time is required.

In such a situation, an induction heating type fixing device in which the fixing roller is heated by eddy current due to electromagnetic waves, or a heat generating layer such as an electric resistor is provided on the peripheral surface of the fixing roller via an insulating layer. However, the direct heating type (surface resistance heating type) fixing device that generates heat can dramatically shorten the startup time, and the preheating (reuse time) required by the conventional halogen lamp method is required. Since the temperature of the fixing section is quickly raised to a predetermined temperature, it is not necessary to maintain the temperature of the fixing section even during non-image formation), and unnecessary power can be eliminated, and the heating efficiency is excellent. Therefore, it is attracting attention as an advantageous method for environmental problems.

The simplest and most effective method for shortening the start-up time in the above-mentioned fixing devices of the respective heating systems is to reduce the heat capacity by reducing the thickness of the core metal of the fixing roller.
However, when the thickness of the fixing roller is reduced, the mechanical strength of the roller decreases, and the roller flexes like a bow at the nip where it contacts the pressure roller, reducing the contact pressure at the center, reducing the nip and reducing the fixability. I do.

Here, an example of a fixing device using a conventional fixing roller with a built-in heater will be described with reference to the drawings. FIG.
At 3 and 14, the pressure roller 2 is pressed against the fixing roller 1 containing the halogen lamp 3 therein. The fixing roller 1 is a thin-walled roller, and when pressed against the pressure roller 2, is bent in a bow shape as shown by a broken line.
The amount of deflection of the roller at the axial center is indicated by d. As a result of the bending of the fixing roller, the contact pressure at the central portion is weakened, the nip is reduced, and the fixing property is reduced.

FIG. 15 is a diagram showing the nip amount of the fixing device. The nip width at the roller center is n ₁ with respect to the nip width n ₂ at the roller end, and n ₂ > n _1. ing. In order to prevent the fixing roller from bending when the pressing roller is pressed against the fixing roller (the bending can be ignored), the thickness of the fixing roller is conventionally set to 1 mm or more in the case of an aluminum roller, for example. However, if the thickness of the fixing roller is reduced in order to shorten the rising time, the fixing roller is deflected as described above, and the fixing property is reduced.

When the fixing property is deteriorated, the toner is not fixed on the recording paper, so that the toner drops when rubbed by hand. Further, since the deformation and correction are repeated when the fixing roller rotates, the roller fluctuates, and as a result, paper skew and wrinkles are likely to occur. In addition, since unevenness in rotation occurs due to load fluctuations during rotation, jitter tends to occur in the recorded image.

In order to prevent these problems, various methods for reinforcing the fixing roller have been proposed. For example, Japanese Patent Laying-Open No. 57-155571 discloses a method of providing a rib on the inner surface of a fixing roller. In the case of the invention described in this publication, after applying an external pressure from the outer peripheral surface of the roller and extruding (drawing) the inner surface, the concave portion is cut.

Further, a roller in which a ring-shaped reinforcing member is welded to the inner surface of a thin roller (JP-A-9-218604) and a roller in which radial ribs are provided on the inner surface during extrusion (JP-A-59-155875) and the like are available. Proposed.

[0012]

However, such a conventional fixing roller reinforcing method is effective for the purpose of merely increasing the strength as a result of an actual trial experiment, It was found that because the thickness was increased, that portion took too much time for the temperature rise time (fixing rise time). That is, if the waiting time is not set long, a fixing failure occurs at the time of startup.

That is, it has been found that the strength increase and the rise time are in an opposite relationship, and the region satisfying both as the fixing roller is a very narrow range. SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing roller capable of solving the above-mentioned problems in the conventional thin fixing roller and satisfying both the strength increase and the rise time reduction, and a method of manufacturing the fixing roller.

[0014]

According to the present invention, the above-mentioned object is achieved by providing a fixing roller of a heat fixing device, wherein cross-shaped ribs are provided on the inner peripheral surface of the roller.

Further, in order to solve the above-mentioned problem, the present invention provides a method according to the present invention, wherein the intersecting rib has a plurality of first ribs extending in the longitudinal direction of the roller, and at least one first rib intersecting the first rib. It is proposed to consist of two ribs.

In order to solve the above-mentioned problem, the present invention proposes that the first rib is a straight line parallel to a roller axis. In order to solve the above-mentioned problem, the present invention proposes that the second rib has a ring shape perpendicular to a roller axis.

In order to solve the above-mentioned problem, the present invention proposes that the second rib has a spiral shape along the inner peripheral surface of the roller. Further, in order to solve the above-described problem, the present invention proposes that the second rib includes a rib perpendicular to a roller axis and a spiral rib along an inner peripheral surface of the roller.

Further, in order to solve the above problems, the present invention proposes that the material of the roller is iron. In order to solve the above-mentioned problem, the present invention proposes that the material of the roller is aluminum.

Further, in order to solve the above-mentioned problem, the present invention proposes that the height of each of the intersecting ribs is substantially the same. In order to solve the above-mentioned problem, the present invention proposes that the cross-sectional shape of the first rib is substantially triangular.

According to another aspect of the present invention, there is provided a method of manufacturing a fixing roller of a heat fixing device having a crossed rib on an inner peripheral surface of a roller. It is proposed to simultaneously form a plurality of first ribs extending in the direction when manufacturing a roller core by extrusion.

According to another aspect of the present invention, there is provided a method of manufacturing a fixing roller of a heat fixing device having a crossed rib on an inner peripheral surface of a roller. It is proposed that a plurality of first ribs extending in the direction are simultaneously formed at the time of manufacturing a roller core by drawing.

In order to solve the above-mentioned problem, the present invention proposes that the first rib is extruded or drawn in a straight line parallel to a roller axis. Further, in order to solve the above-mentioned problem, the present invention proposes that after the first rib is simultaneously formed at the time of manufacturing the roller core, a second rib intersecting the first rib is formed.

According to another aspect of the present invention, the second rib has a ring shape perpendicular to a roller shaft.
It is proposed to form the second rib by rolling. In order to solve the above-mentioned problem, according to the present invention, the second rib has a spiral shape along the inner peripheral surface of the roller.
It is proposed that a rib be formed by rolling and the rolling die be rolled at a predetermined angle with respect to the roller shaft during the rolling.

In order to solve the above-mentioned problem, the present invention proposes that after forming the second rib, the outer periphery of the roller is machined into a cylindrical shape by cutting or grinding.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B are cross-sectional views illustrating a configuration of a fixing roller according to an embodiment of the present invention. FIG. 1A is a cross-sectional view in an axial direction, and FIG. 1B is a cross-sectional view perpendicular to an axis.

As shown in FIG. 1, a fixing roller 10 according to this embodiment has a plurality of ribs (hereinafter referred to as vertical ribs) 12 extending in the axial direction on an inner peripheral surface of a roller core 11. ,
A plurality of ribs (hereinafter, referred to as circumferential ribs) 13 extending along the peripheral surface in a direction perpendicular to the axis are provided. In the present embodiment, the longitudinal ribs 12 are provided on the inner peripheral surface of the roller (the inner periphery of the roller is equally divided into 18) so that a total of 18 longitudinal ribs are equally spaced from each other. In the figure, the number of vertical ribs is less than 18 in order to prevent complication. The circumferential ribs 13 are provided in the roller longitudinal direction (axial direction) such that the ribs are at equal intervals. However, the numbers of the vertical ribs 12 and the circumferential ribs 13 are not limited to the present embodiment. Further, instead of arranging the plurality of circumferential ribs 13 at equal intervals, as will be described later, it is also possible to arrange the circumferential ribs 13 at a portion where the strength is desired to be increased, with a narrow interval.

Next, a fixing roller according to a second embodiment of the present invention will be described. As shown in FIG. 2, the fixing roller 20 of this embodiment has a total of 18 longitudinal ribs (which divide the roller inner circumference into 18 equal parts) extending in the axial direction on the inner peripheral surface of the roller core 21. 22 and 1 extending helically along the peripheral surface.
A spiral rib 23 is provided. However, the numbers of the vertical ribs 22 and the spiral ribs 23 are not limited to the present embodiment. It is also possible to provide two or more spiral ribs 23. The spiral pitch of the spiral rib 23 can also be set arbitrarily.

Next, a description will be given of a fixing roller according to a third embodiment of the present invention. As shown in FIG. 3, the fixing roller 30 of this embodiment has a total of 18 longitudinal ribs (which divide the roller inner circumference into 18 equal parts) extending in the axial direction on the inner peripheral surface of the roller core 31. 32, a total of six circumferential ribs 33a arranged three by three near each end of the roller, and a circumferential rib 3
A single helical rib 33 is provided to extend inside the inner portion 3a. However, the numbers of the vertical ribs 32, the circumferential ribs 33a, and the spiral ribs 33b are not limited to the present embodiment. It is also possible to provide two or more spiral ribs 33b. The spiral pitch of the spiral rib 33b can also be set arbitrarily. The installation range and the number of the circumferential ribs 33a are not limited. Further, the circumferential ribs 33a can be arranged at equal intervals, or the interval can be narrowed at an arbitrary portion.

Now, the fixing roller 10 of each of the above embodiments,
20 and 30 will be described in comparison with a conventional fixing roller. The fixing roller 1 shown in FIG. 4 is a conventional fixing roller having a simple cylindrical shape. As described with reference to FIGS. At the bottom). In order for such a simple cylindrical roller to have a negligible deflection, a cored metal thickness of about 1 mm is required. When a simple cylindrical roller having a thickness of 1 mm was tested with a fixing device (with a built-in heater) configured as shown in FIGS. 13 and 14, the rise time (the time required for the roller surface temperature to reach 170 ° C.) was obtained. Was about 15 seconds. The roller material is aluminum and the roller outer diameter is 30 mm. The input power to the halogen lamp 3 is 1200W.

Here, the rise time and strength required for the fixing roller will be described. Conventionally, the thickness of the fixing roller was 1 mm or more, and the bending of the fixing roller during pressurization was negligible. However, when the thickness of the roller is reduced in order to shorten the rise time, the roller is bent and deformed d.
(See FIGS. 13 and 14), which causes problems such as deterioration of fixability, occurrence of paper skew and wrinkles, and occurrence of jitter in a recorded image. Therefore, it is required that the bending deformation of the roller be within a negligible range and that the rising time be short.

As a preferable condition required for a fixing roller capable of high-speed rising, a time required for the surface temperature of the fixing roller to rise from room temperature (room temperature) to 170 ° C. within 9 seconds is set as a preferable condition. Set as optimal goal. In other words, the roller surface temperature rises to 170 ° C. or more 9 seconds after startup. The input power to the fixing heater (halogen lamp) at this time is 1200 W
And

On the other hand, as a strength target, in order to obtain a nip width at which the fixing rate is stabilized, the amount of deflection (displacement on the lower surface) of the central portion in the axial direction of the roller needs to be 0.3 mm or less.
The rubber hardness of the pressure roller at this time is 50 degrees in Asker C hardness. The pressing force from the pressure roller to the fixing roller is 98 N on one side (one side of the roller).

The inventors of the present invention have proposed that a fixing roller used in a fixing device having a structure as shown in FIGS.
Simulation and trial production were repeated with the roller outer diameter of 30 mm and the input power to the halogen lamp of 1200 W as parameters during the experiment so as to approach the target value and satisfy the target value.

For experimental conditions such as the above parameters,
The simple cylindrical roller having a wall thickness of 1 mm has a rise time of about 15 seconds, and is far from the target value of the temperature rise.
Not satisfactory.

An experiment was conducted with a roller having a thickness of 0.4 mm using a simple cylindrical roller (without ribs) similar to the roller 1 shown in FIG. Was.

[Table 1]

That is, the test piece which is a simple cylindrical roller having a thickness of 0.4 mm has a temperature of 187 after 9 seconds of startup.
° C, and the target value of the temperature rise has been cleared. However, in the test specimen, the amount of bending d is 0.645 mm, and the bending is too large.

Next, when an experiment was conducted using a simple cylindrical roller (without ribs) having a wall thickness of 0.45 mm, the results shown in the test specimens in Table 1 were obtained. That is, the temperature of the test body 9 seconds after startup is 178 ° C., and the target value of the temperature rise is cleared. However, the amount of deflection d is 0.6
11 mm, which is also large in the amount of deflection. That is, it is understood that the test specimen and the target satisfy the target value of the temperature rise, but have too low strength.

Next, an experiment was conducted with the fixing roller 50 shown in FIG. As shown in FIG. 5, the fixing roller 50 has a plurality of circumferential ribs 53 provided on the inner surface of a core metal 51 having a thickness of 0.4 mm and perpendicular to the axis (parallel to the roller end surface). Each circumferential rib 5
3 are equally spaced. FIG. 6 shows an enlarged view of a portion A of the roller. In FIG. 6, the width of the circumferential rib 53 is c, the height of the rib 53 is h, and the rib pitch (interval) is p.

That is, the temperature of the test body 9 seconds after startup is 175 ° C., and the target value of the temperature rise is cleared. However, the deflection d is 0.485 mm, which is not yet satisfactory.

The shape is the same as that of FIG.
As a result of an experiment in which the core metal wall thickness was set to 0.45 mm, the results as shown in the test body in Table 1 were obtained. That is, the temperature of the test body 9 seconds after startup is 171 ° C., and the target value of the temperature rise is clear. However, the amount of deflection d is 0.4
07 mm, and the strength is still insufficient.

In a fixing roller having circumferential ribs arranged as shown in FIG. 5, a rib width: c, a rib height: h, and a rib pitch:
An experiment was also conducted with a combination of rollers having different p values. However, when the temperature after startup was about 170 ° C., the lower surface displacement was 0.4 mm or more, and the strength was still weak.

In the fixing roller having the simple cylindrical shape (without ribs) or the circumferential ribs, it is impossible to find a compatible point between the temperature rise and the strength. Therefore, the inventors of the present application devised a new rib shape and continued trial production experiments. That is, the fixing roller 1 of FIGS.
0, 20, and 30.

The fixing roller 10 shown in FIG. 1 is obtained by adding a circumferential rib 13 to a longitudinal rib 12 extending in the axial direction as a reinforcing rib. Looking at the axial sectional view (a),
Since the vertical ribs 12 and the circumferential ribs 13 intersect, the rib shape of the fixing roller 10 is called an intersecting rib.

The fixing roller 20 shown in FIG. 2 is formed by adding a spiral rib 23 to a longitudinal rib 22 extending in the axial direction as a reinforcing rib. Vertical rib 22 and spiral rib 23
Do not intersect at right angles but intersect, so this is also called an intersecting rib.

In the fixing roller 10 shown in FIG.
Although 2 extends in the axial direction (parallel to the axis), the vertical rib 12 may be formed in a spirally twisted shape. When the spiral vertical rib and the spiral rib 23 of the fixing roller 20 shown in FIG. 2 are combined, the shape formed by both ribs becomes a rhombus (a shape in which both ribs intersect with a rhombus), and these are also one of the crossing ribs. is there. Although this rib shape is not shown, it can be said that it is one embodiment of the present invention as a cross rib.

The fixing roller 30 shown in FIG. 3 is obtained by adding circumferential ribs 33a and spiral ribs 33b to longitudinal ribs 32 extending in the axial direction as reinforcing ribs. In the case of the fixing roller 30, the strength is further improved by providing circumferential ribs 33a at bearing portions (portions that come into contact with the bearings) at both ends of the roller. The fixing roller 30 may have a circumferential rib 33a and a spiral rib 33b, or may have a shape in which a vertical rib is spirally twisted.

In any case, by providing a longitudinal rib extending in the longitudinal direction of the roller (a rib parallel to the axis or a rib twisted in a spiral shape) and a circumferential rib or / and a spiral rib, the ribs are vertically and horizontally oriented. By intersecting the direction or the rhombus shape, the effect of increasing the strength of the fixing roller can be brought about.

Incidentally, the fixing rollers 10, 20, 3
At 0, as the rib form of the vertical ribs (including those twisted in a spiral shape) 12, 22, 32, shapes as shown in FIG. 7 or FIG. 8 can be considered. FIG. 7 also has a square rib cross section, which is called a square rib. 8 has a triangular rib cross section and is called a triangular rib. As shown in FIGS. 7 and 8, the width of each rib is c, and the height of each rib is h. In addition, although not shown, the rib cross section may have a trapezoidal shape.

A fixing roller having the rib arrangement (intersecting rib) as shown in FIGS. 1, 2 and 3 and having the rib shape of the square rib of FIG. 7 is called a square intersecting rib, and an experiment was conducted with the fixing roller having the square intersecting rib. , And the results as shown in Table 1 were obtained. At this time, the width c of the square rib is 0.5 mm, and the rib height h is 1.
The number of the vertical ribs is 2 mm, and the number of the vertical ribs is 18 (18 equally divided circumferences).

In this test piece, the lower surface displacement d at the center of the roller was 0.269 mm, and the temperature of the roller 9 seconds after startup was 137 ° C. That is, although the strength was greatly improved and the target value was cleared, the temperature was too low to be satisfactory. However, it has been found that the provision of the cross ribs has a great effect on improving the roller strength, so if the temperature characteristics are improved by devising the rib cross-sectional shape, the rib width, the rib height, etc., the conventional type can be obtained. This can be more advantageous than a fixing roller (with no ribs or a rib in only one direction such as a circumferential rib).

Next, a fixing roller having a rib arrangement (intersecting rib) as shown in FIGS. 1, 2 and 3 and having a rib shape of a triangular rib in FIG. 8 is called a triangular intersecting rib. As a result of the experiment, the results as shown in Table 1 were obtained. At this time, the width c of the triangular ribs is c = 2.2 mm, the height h of the triangular ribs is 0.4 mm, and the number of the vertical ribs is 18 (equal to the circumference of 18).

In this test sample, the lower surface displacement d at the center of the roller was 0.32 mm, and the temperature of the roller 9 seconds after startup was 171 ° C. That is, the strength was improved, and the optimum target value was able to be cleared in terms of temperature rise, and a compatible point between strength and temperature could be found.

Next, a method of manufacturing the fixing roller of the present embodiment will be described. First, as shown in FIG.
A roller tube 41 having a cylindrical shape 1a and provided with a longitudinal rib 42 extending in the axial direction on an inner peripheral surface 41b is formed by extrusion or drawing. Extrusion processing and drawing processing are general plastic working methods, so detailed description is omitted. As described above, the cross-sectional shape of the rib 42 may be a square, a triangle, a trapezoid, or the like. Of course, a rib having a curved cross section can also be manufactured.

Next, as shown in FIG.
A rolling die (rolling roll) 45 is pressed from the outer peripheral side of 1 to apply a force in the center direction. Then, as shown in FIG. 11, a projection is formed inside the roller, and the projection serves as a circumferential rib 43. In addition, the rolling die 45 is provided with the roller tube 41.
It is needless to say that the entire roller outer peripheral surface is rolled (or the roller base tube 41 is rotated) so as to rotate around the periphery of the roller.

Here, by making the heights of the vertical ribs 42 and the circumferential ribs 43 coincide (match), cross ribs having the same height are formed. By matching the heights of the vertical ribs 42 and the circumferential ribs 43, the ribs can be balanced and the strength and
Temperature unevenness can be eliminated.

In the state shown in FIG. 11, since a concave portion 43b (rolling locus of a rolling die) is formed on the outer peripheral surface of the roller tube 41, the outer peripheral surface of the roller tube 41 is flattened by cutting or grinding. The fixing roller 40 (FIG. 12) having a desired thickness (the thickness of the portion without ribs is defined as the roller thickness) is completed.

Although FIGS. 10 to 12 have been described with reference to the case of the circumferential rib, when the spiral rib (see FIG. 2) is formed,
A spiral rib can be formed by rolling the rolling die 45 at a predetermined angle.

As described above, by providing cross-shaped ribs on the inner peripheral surface of the fixing roller, compared with a single-rib fixing roller having no ribs or only one of a circumferential rib and a vertical rib. Thus, the roller strength can be greatly improved. Therefore, the thickness of the fixing roller can be reduced, and the rising time of the fixing roller can be shortened to achieve both the strength and the temperature (rising time).

Further, the temperature characteristics are improved by devising the rib cross-sectional shape, the rib width, the rib height, and the like, thereby achieving both the strength and the rise time (temperature characteristics) required for the high-speed rising fixing roller. Can be.

Further, the cross rib is formed by a first rib (longitudinal rib in the embodiment) extending in the roller longitudinal direction and a second rib (circumferential rib in the embodiment) extending in the roller circumferential direction. The first rib can be provided at the same time as forming the roller tube by extrusion, drawing, or the like, and the first rib can be provided at the same cost as a simple cylindrical roller. In addition, by forming the first rib at the time of forming the roller tube, bending in the axial direction can be reduced (when the vertical rib is made parallel to the axis), and correction is not required. Then, the second rib can be provided after the first rib is provided, and the rib formation as the post-processing can be performed only with the second rib, so that the processing time can be reduced.

When the second rib is a circumferential rib, the structure of the rolling die (rolling roll) is simple, and the die is rolled in only one direction perpendicular to the axis of the fixing roller. By doing so, the processing for forming the second rib can be facilitated. Further, by repeating the same processing operation, a plurality of circumferential ribs can be formed, and cross ribs can be formed with simple equipment. Alternatively, the efficiency of the processing operation can be increased by using a plurality of rolling dies.

In the case where the second rib is a spiral rib, the spiral rib can be formed by inclining a rolling die (rolling roll) at a predetermined angle and rolling, so that the spiral rib can be easily provided. it can. In the case of a circumferential rib, it is necessary to repeat the operation when forming a plurality of ribs. However, in the case of forming a spiral rib, the rib can be continuously formed by one setting.

Further, when both the circumferential rib and the spiral rib are used as the second rib, it is easy to partially increase the strength of the fixing roller. For example, the fixing roller 30 shown in FIG.
In the case of (1), the circumferential rib 33a is arranged at the roller end and the spiral rib 33b is arranged near the center, but the interval between the circumferential ribs 33a arranged at the end is reduced (the pitch is reduced), so that the roller end is narrowed. Strength is improved at the part (part corresponding to the bearing). Alternatively, in the fixing roller 10 of FIG. 1 as well, the strength at that portion can be improved by reducing the interval between the circumferential ribs 13 near the roller end. As described above, by narrowing the interval between the plurality of circumferential ribs arranged at the position where the strength is to be improved, it is possible to easily increase the roller strength at the desired position.

Incidentally, the fixing roller of the present embodiment used in the above-described experiment uses aluminum as a roller material, but iron can also be used as a roller material. An aluminum roller is lightweight and has excellent temperature characteristics, and an iron roller has a higher Young's modulus (higher strength) than aluminum. Therefore, the number of ribs provided can be smaller than that of an aluminum roller.

The roller of the present invention is not limited to a fixing roller having a built-in heater. The present invention can be applied to a fixing roller of a type in which a heater is disposed outside the roller, a direct heating type in which a resistance heating layer is provided on the roller peripheral surface, or an induction heating type, in addition to the type with a built-in heater. In any heating method, the roller strength can be greatly improved by providing the cross-shaped ribs according to the present invention, so that the fixing roller can be made thinner, the rising time of the fixing roller can be shortened, and the strength and the strength can be improved. Temperature (rise time) can be compatible.

[0066]

As described above, according to the fixing roller of the present invention, since the cross-shaped ribs are provided on the inner peripheral surface of the roller, the strength of the roller is greatly improved, and the thickness of the fixing roller can be reduced. . Therefore, the strength and temperature (rise time) can be compatible with each other by shortening the rise time of the fixing roller.

According to the second aspect of the present invention, the cross-shaped rib includes a plurality of first ribs extending in the longitudinal direction of the roller and at least one second rib intersecting the first rib.
The roller can be effectively reinforced by the first rib in the longitudinal direction of the roller and the second rib intersecting the same, and unevenness in strength and temperature in the longitudinal direction of the roller and the direction intersecting with the roller can be minimized.

According to the third aspect of the present invention, since the first rib has a linear shape parallel to the roller axis, the bending strength in the longitudinal direction of the roller can be improved. Also, the first rib can be easily formed.

According to the structure of the fourth aspect, since the second rib has a ring shape perpendicular to the roller shaft, the strength against the collapse of the roller can be improved. According to the configuration of the fifth aspect, since the second rib has a spiral shape along the inner peripheral surface of the roller, both the bending strength and the strength against crushing can be improved. Also, by appropriately setting the pitch of the spiral, the ratio of each strength can be easily set.

According to the structure of claim 6, since the second rib is composed of the rib perpendicular to the roller shaft and the spiral rib along the inner peripheral surface of the roller, it is possible to easily improve the partial strength of the roller. .

According to the structure of claim 7, since the material of the roller is iron, the strength of the roller can be easily increased, and the number of reinforcing ribs can be reduced. According to the configuration of the eighth aspect, since the material of the roller is aluminum, a fixing roller that is lightweight and has excellent temperature characteristics can be easily realized.

According to the ninth aspect of the present invention, the heights of the crossing ribs are substantially the same, so that the ribs can be balanced and unevenness in strength and temperature can be eliminated. According to the configuration of the tenth aspect, since the cross-sectional shape of the first rib is substantially triangular, the surface area is increased by the slope of the triangular cross-section, so that the heat absorption efficiency is increased and the rise time can be reduced, and the roller strength is increased. Becomes possible.

According to the fixing roller manufacturing method of the present invention, a plurality of first ribs extending in the longitudinal direction of the roller among the cross-shaped ribs are extruded or drawn. The first rib can be provided at the same cost as when a fixing roller without ribs is manufactured.

According to the thirteenth aspect, the first rib is extruded or drawn in a straight line parallel to the roller axis.
Bending in the axial direction during molding can be reduced. According to the fourteenth aspect, after the first rib is simultaneously formed at the time of manufacturing the roller core, the second rib intersecting with the first rib is formed, so that the post-processing on the core metal tube is only the formation of the second rib. Thus, the processing time can be reduced, and the processing cost can be reduced.

According to the fifteenth aspect, since the second rib has a ring shape perpendicular to the roller shaft and is formed by rolling, the second rib can be formed with a simple die structure. In addition, it is possible to perform processing in only one direction in which the movement of the rolling die is perpendicular to the roller axis. Further, a plurality of second ribs can be formed by repeating the processing operation, and it becomes possible to form cross ribs with simple equipment.

According to the sixteenth aspect, the second rib has a spiral shape along the inner peripheral surface of the roller, and is formed by rolling, and at the time of the rolling process, the rolling die is inclined by a predetermined angle with respect to the roller shaft. Since the spiral rib is moved, the spiral rib can be easily formed. Further, the spiral rib can be formed by one setting of the processing operation.

According to the seventeenth aspect, after forming the second rib, the outer periphery of the roller is processed into a cylindrical shape by cutting or grinding, so that the unevenness of the outer peripheral surface of the roller due to the rolling process of the second rib is easily flattened, and the efficiency is improved. A fixing roller can be manufactured.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams illustrating a configuration of a fixing roller according to an embodiment of the present invention, in which FIG. 1A is a cross-sectional view in an axial direction, and FIG.

FIGS. 2A and 2B are views showing a configuration of a fixing roller according to a second embodiment of the present invention, wherein FIG. 2A is a sectional view in the axial direction, and FIG. 2B is a sectional view perpendicular to the axis.

FIG. 3 is a sectional view illustrating a configuration of a fixing roller according to a third exemplary embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a conventional simple cylindrical roller;
(A) is a sectional view in the axial direction, and (b) is a sectional view perpendicular to the axis.

5A and 5B are diagrams showing a configuration of a conventional fixing roller provided with circumferential ribs, wherein FIG. 5A is a side view in the axial direction, and FIG. 5B is a cross-sectional view perpendicular to the axis.

FIG. 6 is a partial cross-sectional view for explaining a circumferential rib of the fixing roller.

FIG. 7 is a partial cross-sectional view illustrating an example of a rib configuration of a fixing roller according to the present invention.

FIG. 8 is a partial cross-sectional view showing another example of the rib shape of the fixing roller according to the present invention.

FIGS. 9A and 9B are diagrams illustrating a forming process of a vertical rib in the fixing roller manufacturing method according to the present invention, wherein FIG. 9A is a side view of the roller, and FIG.

FIG. 10 is a partial side view of a roller for explaining a forming process of a circumferential rib by rolling.

FIG. 11 is a partial cross-sectional view showing a circumferential rib formed by rolling.

FIG. 12 is a partial cross-sectional view showing a fixing roller having a flat outer peripheral surface after forming a circumferential rib.

FIG. 13 is a configuration diagram illustrating a fixing device using an example of a conventional fixing roller.

FIG. 14 is a front view showing a fixing roller and a pressure roller of the fixing device.

FIG. 15 is a schematic diagram illustrating a nip between the fixing roller and the pressure roller.

[Explanation of symbols]

 10, 20, 30 Fixing roller 11, 21, 31, 41 Roller tube 12, 22, 32, 42 Vertical rib (first rib) 13, 33a, 43 Circumferential rib (second rib) 23, 33b Spiral rib ( Second rib) 45 Rolling dies

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yoichi Ueda 3-1 Shinmei-do, Shinmei-do, Shimada-cho, Shibata-cho, Miyagi Prefecture Tohoku Ricoh Co., Ltd. (72) Masatoshi Sasaki Shimei, Shimei-cho, Shibata-cho, Miyagi, Japan DO3-1 F-term in Tohoku Ricoh Co., Ltd. (reference) 2H033 AA06 AA30 BB03 BB13 BB26 3J103 AA02 AA63 AA64 AA65 AA73 FA01 FA15 GA02 GA57 GA58 GA60 GA66 HA03 HA32 HA37

Claims (17)

[Claims] 1. A fixing roller of a heat fixing device, wherein a cross-shaped rib is provided on an inner peripheral surface of the roller. 2. The intersecting rib comprises a plurality of first ribs extending in the longitudinal direction of the roller and at least one second rib intersecting the first rib. 2. The fixing roller according to 1. 3. The fixing roller according to claim 2, wherein the first rib has a linear shape parallel to a roller axis. 4. The fixing roller according to claim 2, wherein the second rib has a ring shape perpendicular to a roller axis. 5. The fixing roller according to claim 2, wherein the second rib has a spiral shape along an inner peripheral surface of the roller. 6. The fixing roller according to claim 2, wherein the second rib includes a rib perpendicular to a roller axis and a spiral rib along an inner peripheral surface of the roller. 7. The fixing roller according to claim 1, wherein the material of the roller is iron. 8. The fixing roller according to claim 1, wherein the material of the roller is aluminum. 9. The fixing roller according to claim 1, wherein the height of each of the crossing ribs is substantially the same. 10. The fixing roller according to claim 1, wherein a cross-sectional shape of the first rib is substantially triangular. 11. A method of manufacturing a fixing roller of a heat fixing device having a cross-shaped rib provided on an inner peripheral surface of a roller, wherein a plurality of first ribs extending in a roller longitudinal direction of the cross-shaped rib are provided. A method for manufacturing a fixing roller, comprising simultaneously forming a roller core by extrusion. 12. A method of manufacturing a fixing roller of a heat fixing device having a crossed rib provided on an inner peripheral surface of a roller, wherein a plurality of first ribs extending in a roller longitudinal direction among the crossed ribs are provided. A method for manufacturing a fixing roller, comprising simultaneously forming a roller core metal by drawing. 13. The method according to claim 11, wherein the first rib is extruded or drawn in a straight line parallel to a roller axis. 14. The fixing device according to claim 11, wherein a second rib intersecting with the first rib is formed after the first rib is formed at the same time when a roller core is manufactured. Roller manufacturing method. 15. The method according to claim 14, wherein the second rib has a ring shape perpendicular to a roller axis, and the second rib is formed by rolling. 16. The second rib has a spiral shape along the inner peripheral surface of the roller, and the spiral second rib is formed by rolling.
The method according to claim 14, wherein the rolling die is rolled while being inclined at a predetermined angle with respect to a roller shaft during the rolling process. 17. The method according to claim 15, wherein after forming the second rib, the outer periphery of the roller is processed into a cylindrical shape by cutting or grinding.