JPH10194506A - Installation structure of belt unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the installation structure of a belt unit with a simple constitution which can dissolve the lateral shift of an endless belt by the alignment error of respective rollers of the belt unit at a low cost easily and also without inviting the increase of a work manhour, the increase of the number of parts or the drop of durability of the endless belt. SOLUTION: In the installation structure of a belt unit 3 for positioning and supporting the belt unit 3 mounted an endless belt 4 between plural rollers 5, 6, 7, 8 supported to a unit frame 9 to the frame 2 of a device main body 1, in one side of the unit frame 9 of the belt unit 3, the roller shafts 10, 15 of the rollers 5, 6 of both ends for mounting the endless belt 4 are supported by a first support part 12 and a second support part 14 for the device main body frame 2 respectively and also its other end is supported by a third support part 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt unit mounting structure for positioning and supporting a belt unit widely used in a color image forming apparatus such as a color copying machine, a color printer and the like with respect to the apparatus main body. Things.

[0002]

2. Description of the Related Art In a color image forming apparatus such as a color copying machine or a color printer, as shown in FIG. 6, yellow (Y) formed on latent image carriers (photosensitive members) 21C, 21M, 21Y and 21K is used. ), Magenta (M), cyan (C), and black (K) unfixed toner images on an intermediate transfer body (intermediate transfer belt) 2 composed of an endless belt
2 and the primary transfer is performed, and this unfixed toner image is formed once again on the recording paper 23 from the intermediate transfer belt 22.

[0003] The intermediate transfer belt 22 is
4, idler roller 25, tension roller 26,
A belt unit 29 is formed between a plurality of rollers such as 27 and a unit frame 28 supporting the plurality of rollers 24, 25, 26, and 27. As shown in FIG. 7, the unit frame 28 of the belt unit 29 is positioned and supported by the frame of the apparatus main body 30 at both ends of the roller shafts of the two rollers 24 and 25 of the belt unit 29, or disclosed in JP-A-1-188665. It is fixed to a frame of the apparatus main body by screws or the like as in a copying machine described in the official gazette.

The above-mentioned color printer and Japanese Patent Application Laid-Open No. 1-1
In the copying machine and the like described in JP-A-88665, there is a problem that the intermediate transfer belt 22 is shifted laterally in a direction perpendicular to the conveying direction of the recording paper 23. The causes of this problem are as follows: Alignment error of each roller. (2) Alignment error of each roller due to assembly accuracy. (3) Alignment error of each roller affected by distortion of the apparatus main body due to a step on the surface on which the apparatus is installed. In particular, in a recent device that has been reduced in size and weight, the rigidity of the entire device is reduced, and an alignment error due to the above (3) is likely to occur.

A description will be given of an alignment error of each roller due to a step on the installation surface with reference to FIG. As shown in the figure, the installation portion A of the apparatus body 30
The belt unit 29
Will be lifted by ΔA ′.
At this time, the other support portions 32, 33, and 34 of the belt unit 29 are hardly lifted unless the other installation portions B, C, and D of the apparatus main body 30 are lifted.

Accordingly, the support portion 31 of the belt unit 29
Is lifted by ΔA ′, and torsional deformation occurs. This deformation of the belt unit 29 causes an alignment error of each roller on which the intermediate transfer belt 22 is laid, and causes a lateral displacement of the intermediate transfer belt 22. As a countermeasure against the lateral deviation of the intermediate transfer belt caused by such a roller alignment error, Japanese Patent Application Laid-Open No. Sho 57-115649 has been proposed.
Japanese Patent Application Laid-Open Publication No. H11-163,086 discloses a roller provided with a guide that regulates a side portion of an endless belt and formed by processing a large number of grooves in the rotation direction.

In Japanese Unexamined Patent Application Publication No. Hei 2-157768 or Japanese Unexamined Patent Publication No. Hei 4-16438, a rib is provided inside the endless belt other than the image forming area, and the rib is provided on a roller or a guide. There is disclosed an apparatus in which a position on a side of an endless belt is regulated by following a guide member. However, any of the above-mentioned proposals has problems in that the number of man-hours increases, the yield decreases, the number of parts increases, and the durability of the endless belt decreases.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the size and weight of a belt unit used in a color image forming apparatus and other various apparatuses, which is affected by a step on a surface on which the apparatus is installed. An object of the present invention is to provide a belt unit mounting structure capable of easily eliminating lateral displacement of an endless belt due to an alignment error of each roller of the unit. Another object of the present invention is to provide a belt unit having a simple configuration that can be realized at low cost without eliminating lateral displacement of the endless belt without increasing the number of working steps, increasing the number of parts, or lowering the durability of the endless belt. It is to provide a mounting structure.

[0009]

In order to solve the above-mentioned problems, a belt unit mounting structure according to the present invention comprises a belt unit having an endless belt provided between a plurality of rollers supported by a unit frame. In a mounting structure of a belt unit for positioning and supporting the frame of the main body, the unit frame of the belt unit is supported by the apparatus main body frame on one side and the roller shafts of both ends of the endless belt on which the endless belt is installed are first supported. And the other side is supported at one place of the third support portion, and the belt unit is supported as described above. The belt unit can be lifted even if one of the installation sections of the main unit is lifted by the step on the installation surface and the main unit is set in a distorted state. The diagonal part of the belt unit is slightly lowered, and the entire belt unit is inclined. However, the distortion is minimized, and the influence on the alignment of each roller can be almost eliminated. Can be managed only by the accuracy at the time of assembly.

[0010] In the belt unit mounting structure according to the present invention, in the belt unit mounting structure, the roller shaft supported by the first support portion and the second support portion supporting one side of the unit frame. In this way, the driving roller shaft that transmits the driving force to the driving roller of the endless belt is used as the supporting portion, so that the positional accuracy of the driving input portion can be improved. Without being affected by the movement of the unit.
Can be stabilized.

Further, in the belt unit mounting structure according to the present invention, in the belt unit mounting structure, the three support portions of the first support portion, the second support portion, and the third support portion may be provided. It is characterized in that it is rotatably supported with respect to the apparatus main body frame. By supporting each of the support portions rotatably in this way, the belt unit is tilted due to the effect of the installation surface step. In this case, since the torsional deformation can be absorbed by the relative rotation of each support portion, the occurrence of distortion of the belt unit itself can be further minimized, and the occurrence of alignment error of each roller due to a step on the installation surface is eliminated. be able to.

Further, in the belt unit mounting structure according to the present invention, in the belt unit mounting structure, the third support portion may be formed by connecting the center of a roller shaft of a plurality of rollers on which the endless belt is provided. It is characterized in that it is positioned inside the square, and by setting the position of the third support portion as described above, twisting (distortion) due to its own weight of the belt unit itself can be suppressed. In addition, the rigidity of the belt unit can be further reduced. It is most effective to set the position of the third support portion near the position of the center of gravity of the belt unit.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.
A description will be given based on FIGS. FIG. 1 is a bird's-eye view showing a concept of a belt unit mounting structure according to an embodiment of the present invention, FIG. 2 is a plan view showing a specific configuration thereof, and FIG. 3 is an enlarged plan view showing a first support portion. 4 is a side view of FIG. 3, and FIGS. 5A to 5D are side views for explaining a deformed state of the support portion.

In FIG. 1, reference numeral 1 denotes an apparatus main body of a color image forming apparatus such as a color copying machine or a color printer;
Reference numeral 2 denotes the apparatus body frame. Reference numeral 3 denotes a belt unit installed in the apparatus main body 1. The belt unit 3 includes an endless belt 4 constituting an intermediate transfer member, and a driving roller 5 for driving at least the endless belt 4 that bridges the endless belt 4. A plurality of rollers 5, 6, 7, 8 composed of an idler roller 6 having an endless belt 4 interposed therebetween and tension rollers 7, 8 for applying tension to the endless belt 4, and these rollers 5, 6, 7, 8 It comprises a pair of left and right unit frames 9 to support.

As shown in FIGS. 2, 3, and 4, the belt unit 3 has one end of a drive roller shaft 10 integral with the drive roller 5 held rotatably through the unit frame 9. A first support portion 12 that supports one side of the belt unit 3 with respect to the apparatus main body frame 2 by being rotatably supported by the apparatus main body frame 2 via a bearing 11. An input gear 13 for driving force is attached to one end of the drive gear 10. The other end of the drive roller shaft 10 is rotatably supported by the unit frame 9.

Further, a second support section 14 that supports one side of the belt unit 3 with respect to the apparatus main body frame 2 and forms a pair with the first support section 12 is provided with an idler roller shaft 15 integrated with the idler roller 6. One end is rotatably penetrated through the unit frame 9 and is rotatably supported by the apparatus main body frame 2 via a bearing 16. The other end of the idler roller shaft 15 is connected to the unit frame 9.
It is supported rotatably. Note that both ends of a tension roller shaft integrated with the tension rollers 7 and 8 are rotatably supported by the unit frame 9, respectively.

Further, the belt unit 3 includes an endless belt 4
And a unit frame 9 supporting the roller shafts of the rollers 5, 6, 7, and 8, formed in a polygonal shape. On the opposite side of the first support part 14, it is supported by the apparatus main body frame 2 via the third support part 17.

The third support portion 17 is disposed so as to be located inside a polygon connecting the center of the roller shafts of a plurality of rollers 5, 6, 7, 8 on which the endless belt 4 is laid. It is most desirable to dispose it at the position of the center of gravity of the unit 3 itself.
The fixed shaft 18 is supported by the apparatus main body frame 2 via a bearing 19. The third support portion 17 may be configured such that the roller shafts of the tension rollers 7 and 8 other than the drive roller 5 and the idler roller 6 are used as the support portions.

Thus, according to the above embodiment, FIG.
Assuming that the installation portion A at one end of the apparatus main body 1 has been lifted by ΔA due to the effect of a step on the installation surface as shown in FIG.
As a result, the main body frame 2 of the belt unit 3
Is raised by ΔA ′.
The lifting amount ΔA ′ is determined by the distance L1 from the installation part D to the installation part A of the apparatus main body 1, and the distance from the installation part D to the first support part 12.
ΔA ′ = L2 · ΔA / L, where L2 is the distance to
It becomes 1.

At this time, the other installation sections B of the apparatus main body 1
Since C and D are not lifted by the step surface, the apparatus main body 1 is installed with only the installation portion A lifted and installed in a distorted state. Looking at how the distortion of the apparatus main body 1 affects the belt unit 3, the first support portion 12 of the belt unit 3 has ΔA ′
However, the lifting amount of the second support portion 14 is a minute amount smaller than ΔA ′, which is only a negligible amount, and the third support portion 17 is not lifted at all.

The belt unit 3 is rotatably supported with respect to the apparatus body frame 2 by a first support portion 12, a second support portion 14, and a third support portion 17, respectively.
5A is lifted from the state of FIG. 5A as shown in FIG. 5B, the first support portion 12 is lifted from the state of FIG.
The lifting amount of the support unit 12 is small ΔA ′, and the inclination of the belt unit 3 is smaller than the inclination of the apparatus main body 1. Due to the rotation, the distortion of the apparatus main body 1 is absorbed here.

Similarly, the second support portion 14 and the third support portion 1
7 is also supported rotatably with respect to the apparatus main body 1,
The belt unit 3 slightly tilted by the first support portion 12
The second support portion 14 and the third support portion 17 can also rotate relative to the device main body 1 and move independently of the device main body 1, and thus are diagonal to the first support portion 12. Although the belt unit 3 is displaced by ΔE in the reverse direction at the portion and the belt unit 3 itself is inclined, almost no distortion occurs, and the alignment of each roller is not affected.

This means that the distortion of the apparatus main body 1 is hardly transmitted to the belt unit 3 side, and eliminates the alignment error of each roller which is affected by the distortion of the apparatus main body 1 due to a step on the surface on which the apparatus is installed. As a result, the lateral displacement of the endless belt 4 of the belt unit 3 can be managed only by the accuracy error at the time of assembly. In addition, since the first support portion 12 that supports one side of the unit frame 9 to the device main body frame 2 is configured to rotatably support the drive roller shaft 10, the positional accuracy of the drive input portion can be reduced. It can be stabilized without being affected by the movement of the main body 1 and the belt unit 3.

Further, by arranging the third support portion 17 so as to be located inside a polygon connecting the center of the roller shafts of the plurality of rollers 5, 6, 7, 8 on which the endless belt 4 is laid, the belt is provided. Torsion (distortion) of unit 3 itself due to its own weight
Therefore, the rigidity of the belt unit 3 can be further reduced, and thus the weight of the belt unit 3 can be further reduced and the cost can be reduced.
The position of the third support portion 17 is most effective near the center of gravity of the belt unit 3 if structurally permitted, and the greatest effect can be expected.

On the other hand, in the above embodiment, the first support 1
2, the second support portion 14 and the third support portion 17 are configured by rotatably supporting the respective shafts 10, 15, 18 via bearings 11, 16, 19 installed on the apparatus body frame 2 side. However, a bearing is installed on the belt unit 3 side, and each shaft 1 is mounted on the apparatus body frame 2 side.
0, 15, and 18 may be held through.

Each of the support portions 12, 14, and 17 is rotatably formed. This structure is more effective in eliminating the distortion of the belt unit 3, but is necessarily rotatably supported. It is not necessary to fix the belt unit 3 to the apparatus body frame 2 at the three positions of the support portions 12, 14, and 17 as described above. Can suppress the influence of distortion.

As shown in FIGS. 5 (C) and 5 (D), even if the support shaft is the square shaft 10A, the apparatus main body frame 2
According to the deformation of the unit frame 9 of the belt unit 3
However, as shown in FIG. 5 (D), the distortion near the support portion of the belt unit 3 is minimal, the alignment change of the endless belt 4 of the belt unit 3 is small, and the rigidity of the unit frame 9 is slightly reduced. This is because by increasing the height, distortion near the support portion can be minimized, and a change in alignment can be minimized.

The belt unit according to the present invention comprises:
A belt unit in which an endless belt is provided between a plurality of rollers can be widely applied without being limited to the intermediate transfer belt of the color image forming apparatus.

[0029]

As described above, according to the belt unit mounting structure according to the present invention, the belt unit is mounted on the apparatus body frame, and one end of the unit frame is provided with an endless belt. Since the shafts are respectively supported at two places of the first support part and the second support part, and the other side is supported at one place of the third support part, the apparatus main body is distorted due to a step of the installation surface. Even if the belt unit is installed in an inclined state, the belt unit is merely tilted as a whole, and is hardly affected by the distortion of the apparatus main body, so that the distortion of the belt unit can be minimized.

Therefore, it is possible to substantially eliminate the influence on the alignment of each roller due to the step on the surface on which the apparatus is installed, and to manage the lateral displacement of the belt with only the accuracy at the time of assembly. Also, instead of countermeasures with cost impact such as grooved rollers and ribbed belts, it is possible to eliminate belt lateral displacement with a simple configuration only by changing the support part, which increases the number of work steps and the number of parts. It is possible to realize a countermeasure for the lateral displacement of the belt at low cost without increasing the number of times or reducing the durability of the belt, and to improve the reliability of the belt unit.

[Brief description of the drawings]

FIG. 1 is a bird's-eye view showing a concept of a mounting structure of a belt unit according to an embodiment of the present invention.

FIG. 2 is a plan view showing a specific configuration of a belt unit mounting structure according to the embodiment of the present invention.

FIG. 3 is an enlarged plan view showing a first support portion of the belt unit mounting structure according to the embodiment of the present invention.

FIG. 4 is a side view of FIG. 3 showing an enlarged first support portion of the belt unit mounting structure according to the embodiment of the present invention.

FIG. 5 is a side view illustrating a deformed state of a support portion of the belt unit mounting structure according to the embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing an example of a conventional color image forming apparatus.

FIG. 7 is a bird's-eye view showing a concept of a mounting structure of a belt unit in a conventional color image forming apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Device main body 2 Device main body frame 3 Belt unit 4 Endless belt 5 Drive roller 6 Idler roller 7, 8 Tension roller 9 Unit frame 10 Drive roller shaft 11, 16, 19 Bearing 12 First support part 14 Second support part 15 Idler roller Shaft 17 Third support part 18 Fixed shaft

Claims (4)

[Claims] 1. A belt unit mounting structure for positioning and supporting a belt unit comprising a plurality of rollers supported by a unit frame and a plurality of rollers supported by the unit frame on a frame of an apparatus body, wherein the unit frame of the belt unit is connected to the apparatus. With respect to the main body frame, one side supports the roller shafts of the rollers at both ends on which the endless belt is erected, at two places of a first support section and a second support section, and the other side of the third support section. 1
A belt unit mounting structure characterized by being supported in several places. 2. The belt according to claim 1, wherein one of said roller shafts supported by said first support portion and said second support portion supporting one side of said unit frame is used as a drive roller shaft. Unit mounting structure. 3. The first support portion, the second support portion, and the third support portion.
3. The belt unit mounting structure according to claim 1, wherein three supporting portions of the supporting portion are rotatably supported on the apparatus main body frame. 4. The apparatus according to claim 1, wherein the third support portion is located inside a polygon connecting the center of the roller shafts of the plurality of rollers on which the endless belt is provided.
The mounting structure of the described belt unit.