JP2008139638A - Roller for belt, belt driving device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that because it is easy to generate the biasing of a belt, during driving of the belt and there is a risk that it causes the damage of the end portion of the belt, a biasing regulating member for the inner circumferential surface of the belt is stuck, a belt biasing stopping ring is installed to a roller shaft end portion, a supporting member control mechanism for the belt is mounted, or the like, as countermeasures, but when a high biasing force is generated, the biasing can not be prevented with the regulating member or the biasing stopping ring and a problem of installation space and cost in the belt biasing control mechanism, in a belt fixing system used for an electrophotographic machine. <P>SOLUTION: In a roller for the belt, when the front layer of the roller is polished, for instance the center of the roller is set as a dividing position and a grindstone is moved to both end portions from the dividing position, although the direction of moving the grindstone in the axial direction of the roller is unidirectional in a conventional manner. Thus, polishing marks formed on the front layer of the roller are formed in two directions opposite to each other from the dividing position and the force of the biasing of the belt generated by the polishing marks is uniform on both sides, to suppress the biasing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a belt driving device and a belt fixing device used in an electrophotographic apparatus using an electrophotographic process such as a copying machine and a printer.

Conventionally, a fixing method using a belt has been used as a fixing device used in electrophotographic equipment. In this belt fixing method, if the belt end is damaged due to the deviation of the belt when the belt is driven, the fixing device is used. As a result, the function is significantly reduced. As measures against this, there are attachment of a deviation regulating member on the inner peripheral surface of the belt, installation of a belt deviation retaining ring at the end of the roller shaft, installation of a belt support member control mechanism (for example, see Patent Document 1), and the like.
However, when a strong offset force is generated, the countermeasure by sticking the regulating member is likely to cause peeling of the member or the belt, and the countermeasure by installing the belt offset ring is damaged by buckling of the belt end. Is likely to occur. Further, when the belt deviation control mechanism is mounted on the fixing device, there are problems of installation space and cost.

JP 2000-199550 A

  An object of the present invention is to reduce the deviation of the fixing belt without being caught by the conventional configuration.

In the first aspect of the present invention, a surface layer is formed by polishing using a grindstone, and the surface layer is formed in two directions caused by a difference in polishing direction with a distribution position in a longitudinal direction of the roller as a boundary. It is characterized by a mixture of abrasive eyes.
According to a second aspect of the present invention, in the belt roller according to the first aspect, there are a plurality of the sorting positions.

According to a third aspect of the present invention, in the belt roller according to the first aspect, the distribution position is one location, and the polishing marks in the two directions are polished toward the both end portions from the distribution position, respectively. It is characterized by having a polished eye.
According to a fourth aspect of the present invention, in the belt roller according to the first aspect, the distribution position is one place, and the polishing marks in the two directions are respectively polished from both end sides toward the distribution position. It is characterized by having a polished eye.
According to a fifth aspect of the present invention, in the belt roller according to any one of the first to fourth aspects, the polishing marks are erased in the vicinity of the sorting position.

According to a sixth aspect of the present invention, in the belt roller according to any one of the first to fifth aspects, the roller is a foamed silicon roller.
The invention according to claim 7 is characterized by a belt driving device using the belt roller according to any one of claims 1 to 6.
According to an eighth aspect of the present invention, in the belt driving device according to the seventh aspect, the sorting position is substantially at the center in the longitudinal direction of the roller.

According to the ninth aspect of the present invention, in the belt driving device according to the seventh aspect, when the belt deviation occurs due to a factor resulting from the design characteristics of the belt driving device, the belt deviation is eliminated. Further, the distribution position is shifted by a predetermined amount in a predetermined direction from the central portion of the roller.
According to a tenth aspect of the present invention, in the belt drive device according to any one of the seventh to ninth aspects, the roller is used in a rotation direction opposite to a rotation direction of the roller during polishing. To do.
According to an eleventh aspect of the present invention, in the belt driving device according to any one of the first to ninth aspects, the roller is a fixing roller, the belt is a fixing belt, and at least one heat source is provided. It can be used as a heat fixing device.
According to a twelfth aspect of the present invention, there is provided an image forming apparatus including the belt driving device according to the eleventh aspect as a heat fixing device.

  According to the present invention, since the polishing in the roller axial direction is not unidirectional with respect to the entire length of the roller, it is possible to suppress the deviation of the belt caused by the lateral deviation of the configuration and members. This can be realized at low cost without using the conventional mechanical control technology.

FIG. 1 is a conceptual diagram of a belt fixing device.
In the figure, reference numeral 1 denotes a fixing belt, 2 denotes a fixing roller (drive roller), 3 denotes a driven roller, 4 denotes a tension roller, 5 denotes a pressure roller, and 6 denotes a halogen heater as a heat source.
FIG. 2 is a perspective view of the belt fixing device.
In the figure, symbol A indicates the direction of belt slip.
The fixing belt 1 spans the fixing roller 2, the driven roller 3, and the tension roller 4, and the pressure roller 5 is pressure-supported with respect to the fixing belt 1 to secure a nip.
In the case of the heat fixing device, a heat source 6 such as a halogen heater is incorporated in the driven roller 3 so as to heat the belt 1 through the surface of the driven roller 3. In addition, there is one in which a heat source is incorporated in the pressure roller 5.
In such a belt fixing device, the deviation of the belt in the axial direction of the roller (in the direction of arrow A in FIG. 2) occurs as shown in FIG.

FIG. 3 is a schematic diagram showing a temporal change (shift) of the belt end position. FIG. 4A is a diagram showing the definition of the offset direction, and FIG. 4B is a graph schematically showing the displacement of the belt.
In FIG. 5A, the design reference position of the right end portion of the belt is defined as the position of displacement 0, and the right direction from that position is defined as the + side.
In FIG. 5B, the vertical axis indicates the position of the belt end, and the horizontal axis indicates the cumulative usage time.
The endless belt stretched between the two rollers rotates in one direction due to the rotation of the roller. However, due to various factors such as the deviation of the parallelism of the rollers and the imbalance of the tension on the left and right sides of the belt, May occur. In many cases, once the deviation occurs, as shown in FIG. 3, the deviation proceeds in the same direction, and finally the belt comes off the roller, or the belt end part contacts other members and breaks. This causes a problem that

FIG. 4 is a diagram showing a general method for producing a roller used in the fixing device.
FIG. 5 is a diagram schematically showing the polishing eyes generated on the surface of the roller. FIG. 4A shows a case where the grindstone is moved from left to right, and FIG. 4B shows a case where the grindstone is moved from right to left.
In a fixing device, a foamed silicon roller is often used as a fixing roller in order to secure a nip region. As shown in FIG. 4, the foamed silicon roller is manufactured by foaming silicon rubber around the core metal and polishing the surface in one direction of the arrow C in the axial direction by a grindstone rotating in the direction of the arrow B. In the present invention, the direction of arrow C is referred to as the polishing direction. At this time, the fixing roller is also rotated, but by changing the direction of the arrow B or the arrow C (that is, the polishing direction), rollers having different characteristics can be formed.
In the following, the fixing roller 2 will be described as an example, but the same effect can be expected by adopting the same configuration as long as it is a roller that bridges the belt.

Depending on the respective polishing directions, as shown in FIG. 5, polishing marks in a direction inclined with respect to the roller rotation direction are generated, which is considered to be one of the left and right deviations of the member that is the cause of the belt shift.
The fixing roller and the grindstone are rotated in the direction in which the relative speed is increased, that is, both clockwise and counterclockwise when viewed from one shaft end. This maximizes the relative speed at the contact point (polishing position) between the two. The smaller the lateral feed speed of the grindstone is, the smaller the amount of inclination of the polishing mesh becomes, so that the belt shift due to this may be small, but it is not a good idea to make it too slow because of the problem of processing efficiency.
By polishing, a minute ridge is generated on the roller surface. When this microscopic view is seen microscopically, it has a scaly shape that flows toward the downstream in the rotational direction of the roller. In actual use, the case where the fixing roller is used while being rotated in the same direction as the rotation direction at the time of creation is referred to as “order”, and the opposite method is referred to as “reverse eye”.

FIG. 6 is a diagram showing a difference in the belt deviation due to a difference in the polishing eyes of the roller. FIG. 6 (a) is a deviation graph when the roller shown in FIG. 5 (a) is used, and FIG. 6 (b) is a deviation graph when the roller shown in FIG. 5 (b) is used.
5A, the fixing roller polished in one direction from the left end of the foamed silicon roller (the left end of the transfer paper in the moving direction) to the right end, and one direction from the right end to the left end in FIG. 5B. FIG. 6 shows a time history of the shift amount when the fixing roller polished on the surface is used. It became clear that the amount of deviation of the belt changes with changes in the polishing direction. Further, when the roller without polishing was confirmed, no deviation occurred.
From this result, it is considered that the use of a roller having no difference in the horizontal direction with respect to the polishing eye is a measure for reducing the deviation of the belt.

FIG. 7 is a view for explaining a polishing method for a belt roller of the present invention. The figure (a) is the figure of the grinding | polishing eyes at the time of grind | polishing in two directions toward the edge part on either side from the roller center, The figure (b) is divided into two directions toward the center from the edge part on the left and right. It is a figure of a polish eye at the time of polish.
This figure is a schematic view of a roller in which polishing eyes are formed symmetrically. A boundary portion between the two-direction polishing eyes is referred to as a sorting position in the polishing direction. In addition to this example, although not shown, the longitudinal direction of the roller may be divided into four to divide the polishing eyes alternately (three distribution positions), and the two on the central side of the four divisions should have the same polishing direction. The quarter of both ends may be reversed in the reverse polishing direction (two sorting positions). In short, the basic principle of the present invention is to mix both directions of polishing marks on the same roller surface layer. As a general rule, the areas (total) of the polishing marks in the respective directions are made to have substantially the same length. However, if the processing steps become complicated, the efficiency of manufacturing decreases, so it is better to keep it to the minimum necessary.
In the distribution position, the grindstone may be polished to a predetermined position without being moved after being positioned at the distribution position so that there is no polishing residue, and the slanted polishing marks at the boundary portion may be erased by the width of the grindstone. However, when the polishing eyes are erased, the boundary between the polishing eyes in the two directions disappears. In this case, the portion where the polishing eyes are erased will be referred to as a distribution position.
In the current manufacturing process, the designation of the polishing eye is determined in one direction from the viewpoint of processing efficiency, but the deviation can be suppressed by designating the polishing eye as described above in consideration of the left and right deviation characteristics.

FIG. 8 is a view showing the belt shift by the roller polished from the center toward the end.
FIG. 9 is a view showing the belt shift by the roller polished from the end toward the center.
In both figures, a broken line is shown with reference to the figure near the belt in each case where the two types of rollers shown in FIG. 5 are attached (the same applies to the following figures).
In FIG. 8, by polishing the surface layer from the central part of the roller to the end part, the axial force that the belt receives from the roller is positive from the central part of the roller to the right end part. On the left side, the same force in the opposite direction works symmetrically, and as a result, the shift in composition is suppressed. The reason why the deviation does not become zero completely is presumed that, in this configuration, the cause of the belt deviation is caused by other than the polishing eyes. For confirmation, a non-polished fixing roller was attached and the belt deviation was examined. As a result, a deviation similar to the above occurred.

In FIG. 9, by polishing the surface layer from the end of the roller to the center, the axial force that the belt receives from the roller is positive in the direction of the center from the left end of the roller. Since the same force in the opposite direction works symmetrically from the right side, as a result, the shift in composition is suppressed.
As shown in FIGS. 8 and 9, by polishing the roller from the center to the outside in the axial direction or from the end to the center, a piece of the belt caused by deviation of the frictional force of the roller when the belt is driven. The shift can be suppressed.
As can be seen from the results of FIGS. 8 and 9, if the polishing eyes are symmetrical, even if polishing is performed from the center to the end, or from the end to the center, the belt is offset. There is almost no difference. In the following drawings, only the case of polishing from the roller center to the end will be considered.

FIG. 10 is a diagram showing a countermeasure when the belt deviation occurs due to the design characteristics of the apparatus.
In the figure, G0 is a graph of the belt side by the roller polished by the roller center sorting, and G1 / 4 is a belt side graph by the roller polished by shifting the sorting position from the center to the right by a quarter of the total length of the roller. Each is shown.
As shown in FIGS. 8 and 9, in the case of a configuration in which there is a factor of the belt deviation other than the polishing eye, when it is known that this is a deviation peculiar to the model and not a mere manufacturing error. The roller polishing method can be set in consideration of the belt deviation amount.
That is, in this example, even if the polishing is performed by the central distribution, the belt deviation still remains on the plus side. Therefore, an arrangement that increases the factor of deviation on the minus side is considered. In this configuration, the left and right sorting positions were shifted from the center of the roller to the right by a quarter of the total length of the roller, and polished from the sorting position toward the end.
As a result of driving the belt using this fixing roller, there was almost no deviation of the belt.
Therefore, the fixing device having this configuration may be manufactured by fixing the polishing method for all the fixing rollers to the above method.
As in this example, for the reason of the configuration of the fixing device and the like, the deviation of the generated belt may be set appropriately according to the degree of the shift direction and the shift amount.

FIG. 11 is a diagram illustrating a case where the shift amount of the sorting position is changed in relation to the drive source.
In the figure, reference symbol G1 / 3 shows a graph of the belt offset by the roller polished by shifting the sorting position from the center to the right by one third of the entire length of the roller.
When the fixing device is driven on one side, the belt is shifted toward the non-driving side. It is assumed that the deviation of the result is G0 (center → edge) of the solid line in FIG.
In this configuration, the left and right sorting positions were shifted from the center of the roller to the right by one third of the total length of the roller, and polished from the sorting position toward the end.
As a result of driving the belt using this fixing roller, as shown by a solid line G1 / 3 in FIG.
Therefore, in the fixing device having this configuration, the polishing method for all the fixing rollers is fixed in the predetermined direction (in this example, from the center to the right) and in a predetermined amount (in this example, one third of the entire length of the roller). Can be manufactured. However, the setting of the sorting position is not limited to the above-mentioned one third, and is set to a value that can minimize the deviation of the belt according to the actual characteristics of the apparatus.
In all of the examples shown in FIGS. 10 and 11, since the belt deviation is in the plus direction, the left and right sorting position at the start of polishing is shifted to the right. The position may be shifted by a predetermined amount in the left direction.
As described above, when there is a deviation due to the structure of the fixing device or the main body structure, the deviation of the belt can be suppressed by shifting the distribution position of the surface polishing from the center.

FIG. 12 is a diagram for explaining a difference in deviation due to the difference between the first order and the reverse order.
This figure is a graph showing the belt bias when the two types of rollers shown in FIG.
As described above, the case where the rotation of the roller is the same direction during polishing and the actual use is referred to as normal use, and the case where the roller is in the reverse direction is referred to as reverse use.
As is apparent from the figure, the absolute value of the belt movement amount is smaller when the reverse roller is used in either of the two types of rollers than when the roller is used in the forward direction. The same can be said for the offset due to the configuration of the fixing device. Therefore, even when the fixing roller as shown in FIG. 7 is used, the composite deviation amount is reduced when the reverse eye is used.

It is known that the reverse eye use has a higher frictional resistance with the belt than the normal use. Due to the difference in the magnitude of the frictional resistance, the magnitude of the lateral displacement of the belt varies. That is, since a frictional resistance force is generated in opposition to the lateral movement force by the polishing eye, it is considered that the amount of lateral movement is smaller when the frictional resistance is larger than when the frictional resistance is small.
Therefore, unless there is another reason for selecting the order, it is better to use it with the reverse eye in order to reduce the belt deviation.
If the core of the roller is configured symmetrically with respect to the center of the roller, switching the left and right of the roller will change the order and the reverse order. To prevent assembly errors during manufacturing, the core is designed asymmetrically. It is good to leave.

  For the sake of convenience of explanation, the fixing device has been described as an example. However, the basis of the present invention is a combination of a belt roller that forms a surface layer by polishing with a grindstone and a belt spanned around the roller. The present invention is applicable to belt driving devices in general. Accordingly, the roller is not limited to a foamed silicon roller, and is not particularly limited as long as it uses a material suitable for polishing.

FIG. 13 is a view showing an example of an image forming apparatus using the belt driving device of the present invention as a fixing device.
In the figure, reference numeral 100 denotes an image forming apparatus, 101 denotes a photoconductor as an image carrier, 102 denotes an exposure apparatus that forms a latent image by applying a light beam modulated by image information to the photoconductor, and 103 reveals the latent image with toner. A developing device 104 for image formation, a transfer belt 104 for primary transfer by superimposing a plurality of color toner images formed on a photoconductor, a transfer device 105, and a toner image on the transfer belt 106 on a transfer sheet as a recording medium A secondary transfer device for transfer, 107 is a fixing device using the belt driving device of the present invention, 108 is a built-in paper feeding device, 109 is an external paper feeding device, and P is transfer paper.
A heat source is built in the driven roller of the belt driving device of the present invention, and the heat fixing device 107 is incorporated in the image forming apparatus 100. The full-color image primarily transferred onto the transfer belt 104 is secondarily transferred to the recording paper P by the secondary transfer device 106, and the toner image transferred onto the recording paper by the heat fixing device 107 is thermally fixed. Since this fixing device uses the roller according to the present invention, even when used for a long period of time, the belt is not displaced and stable image formation can be performed.

It is a conceptual diagram of a belt fixing device. It is a perspective view of a belt fixing device. It is a schematic diagram which shows the time change (deviation) of a belt edge part position. It is a figure which shows the general manufacturing method of the roller used for a fixing device. It is a figure which shows typically the grinding | polishing eyes which arise on the surface of a roller. It is a figure which shows the difference in the belt offset by the difference in the grinding | polishing eyes of a roller. It is a figure for demonstrating the grinding | polishing method of the roller for belts of this invention. It is a figure which shows the belt side shift by the roller grind | polished toward the edge part from the center. It is a figure which shows the belt side shift by the roller grind | polished toward the center from the edge part. It is a figure which shows the coping method when the belt deviation arises on the basis of the design characteristic of the apparatus. It is a figure which shows the case where the shift amount of the sorting position is changed in relation to the drive source. It is a figure for demonstrating the difference of the offset by the difference of an order and a reverse eye. 1 is a diagram illustrating an example of an image forming apparatus using a belt driving device of the present invention as a fixing device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixing belt 2 Fixing roller 3 Driven roller 4 Tension roller 5 Pressure roller

Claims (12)

  A roller in which a surface layer is formed by polishing using a grindstone, wherein the surface layer has two-direction polishing marks mixed due to a difference in a polishing direction with a distribution position in a longitudinal direction of the roller as a boundary. Characteristic roller for belt.   The belt roller according to claim 1, wherein there are a plurality of sorting positions.   2. The belt roller according to claim 1, wherein the sorting position is one place, and the polishing marks in the two directions are polishing marks when being polished from the sorting position toward both ends. Characteristic roller for belt.   2. The belt roller according to claim 1, wherein the sorting position is one place, and the polishing marks in the two directions are polishing marks when being polished from both ends toward the sorting position, respectively. Characteristic roller for belt.   The belt roller according to any one of claims 1 to 4, wherein the polishing marks are erased in the vicinity of the sorting position.   6. The belt roller according to claim 1, wherein the roller is a foamed silicon roller.   A belt driving device using the belt roller according to any one of claims 1 to 6.   8. The belt driving device according to claim 7, wherein the sorting position is substantially in the center in the longitudinal direction of the roller.   8. The belt driving device according to claim 7, wherein when a belt offset occurs due to a factor resulting from a design characteristic of the belt driving device, the distribution position is set to a central portion of the roller in order to eliminate the belt offset. A belt driving device characterized in that the belt driving device is shifted by a predetermined amount in a predetermined direction.   10. The belt driving device according to claim 7, wherein the roller is used in a rotation direction opposite to a roller rotation direction during polishing.   10. The belt driving device according to claim 1, wherein the roller is a fixing roller, the belt is a fixing belt, and further includes at least one heat source and can be used as a heat fixing device. A belt drive device characterized by that.   An image forming apparatus comprising the belt driving device according to claim 11 as a heat fixing device.

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