JP2001088975A - Sheet transport device - Google Patents

Abstract

(57) [Problem] To provide a sheet conveying device capable of reducing the occurrence of linear bending of an image due to a delicate difference in bearing shapes at both ends even when a bearing member utilizing the leverage principle is used. And
Further, the present invention provides an inexpensive sheet conveying apparatus with a reduced number of parts. A bearing portion for supporting a driven roller, a receiving portion for supporting a spring, and provided between the bearing portion and the receiving portion and rotatably mounted on a side plate. A bearing member 10 having a fulcrum 13 is provided, and the bearing member 10 has a symmetrical portion when divided by a plane passing through the center thereof and orthogonal to the axial direction of the roller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device of an image forming apparatus such as a copying machine, a printer, a facsimile, and the like.

[0002]

2. Description of the Related Art As described in Japanese Patent Application Laid-Open No. H11-20981, Japanese Patent Publication No. H8-25662, and Japanese Patent No. 2748254, a method for conveying a sheet such as transfer paper is performed by a frictional force of a rubber roller or the like. It is well known. In order to obtain a frictional force for conveying the sheet, the driving roller and the driven roller must be pressed against each other. Generally, as shown in FIGS. 6 and 7, the bearing 103 of the driven roller 102 is fixed by a spring 104 or the like. The method of applying pressure is taken. As the direction of pressing, it is most efficient to press the driven roller 102 straight toward the driving roller 101, and the above-described invention also employs this method.

[0003] However, in a case often used in a sheet conveying device of an image forming apparatus or the like, as shown by a dotted line in FIG. In this case, as shown in FIG. 8, the lever 103 is used as a pressing member utilizing the principle of leverage, or as shown in FIG.
By supporting the driven roller 102 on the drive roller 101, the driven roller 102 can be pressed against the drive roller 101 by the elastic force of the spring 104 arranged on the side of the roller.

[0004] Further, as shown in FIG.
As a fulcrum, a shaft 106 is extended from the side plate 107 and its shaft 1
06, the groove 106a is cut into a retaining ring 10 such as an E-shaped ring.
8, the thrust direction is fixed.

[0005]

However, in the case of the pressurizing method utilizing the above-mentioned leverage principle, particularly in the case where the positional accuracy of the conveyance is strictly required like a registration roller, the bearing shape at both ends is delicate. Such a difference may cause a difference in the pressing force in the left-right direction, or the position of the axial center may be deviated from the target. As a result, there has been a problem that the transfer paper may be skewed or a straight image may be bent.

In the method of fixing the bearing 103 in the thrust direction by the retaining ring 107, the number of parts is reduced to 10
6. Since two points of the retaining ring 107 are required and the processing cost is increased, there is a problem that the cost is high.

The present invention solves the above-mentioned conventional problems,
It is another object of the present invention to provide a sheet conveying apparatus that can reduce the occurrence of linear bending of an image due to a slight difference in bearing shape at both ends even when a bearing member utilizing the leverage principle is used. An object of the present invention is to provide an inexpensive sheet conveying apparatus with a reduced number of components.

[0008]

In order to solve the above-mentioned problems, the present invention provides a pair of rollers whose both ends are rotatably supported by side plates, and presses one roller of the pair of rollers against the other roller. Pressurizing means, and a sheet conveying device for nipping and conveying the sheet by the roller pair,
A bearing portion that supports the one roller, a pressing portion supporting portion that supports the pressing portion, and a rotating portion that is provided between the bearing portion and the pressing portion supporting portion and is rotatably mounted on the side plate. A bearing member having a fulcrum portion is provided, and the bearing member is characterized in that its portion when divided along a plane passing through the center and orthogonal to the axial direction of the roller is left-right symmetric.

The present invention is effective when the bearing member is an injection-molded product and the bearing member is provided with a mark for identifying an injection-molded mold. Further, in order to solve the above problem, the present invention has a pair of rollers each of which is rotatably supported on a side plate, and a pressing means for pressing one roller of the roller pair to the other roller. In the sheet transporting apparatus for nipping and transporting a sheet by the pair of rollers, a bearing portion that supports the one roller, a pressing portion supporting portion that supports the pressing portion, and the bearing portion and the pressing portion supporting portion. A bearing member having a fulcrum portion rotatably mounted on the side plate, the bearing member being made of a synthetic resin, and synthesizing the axial positioning of the roller with the fulcrum portion. It is characterized in that positioning means for performing the adjustment using the elasticity of the resin is provided.

[0010] The present invention is effective when the positioning member provided on the bearing member is provided with at least two pawls which are engaged with the side plate. Further, the present invention is effective when the claw portion is provided with a release assisting portion for prompting an unlocking operation.

Further, the present invention is effective when the bearing member is integrally provided with an axial positioning portion of the one roller.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view showing a main part of the sheet conveying apparatus according to the present invention. In FIG. 1, left and right side plates 1 are arranged in parallel as a main body structure in the image forming apparatus, and the side plates 1 of this example use sheet metal.
You may comprise with a resin frame. Between the left and right side plates 1, a metal core 2a and a drive roller 2 having the core 2a covered with rubber 2b are provided. The drive roller 2 has a small diameter shaft portion 2c at both ends of the core 2a. Formed and this shaft portion 2c
Are rotatably mounted via a bearing 5 mounted on the side plate 1. The bearing 5 may be a copper-based or iron-based sintered bearing impregnated with oil, or a resin bearing.

A driven roller 3 made of metal is disposed above the driving roller 2, and small-diameter shaft portions 3 a are formed at both ends of the driven roller 3. The left and right side plates 1 are formed with arc-shaped long holes 8 into which the shaft portions 3a of the driven roller 3 are loosely fitted, and the leading ends of the shaft portions 3a reach the outside of the side plates 1 through the long holes 8. I have. The shaft 3a of the driven roller 3 is rotatably supported by the side plate 1 via a bearing member 10 described below outside the side plate 1. In this embodiment, the driven roller 3 is pressed against the driven roller 2, but the driven roller 2 may be pressed against the driven roller 3.

The bearing member 10 is a plate-shaped member having an appropriate thickness, and a bearing portion 11 to which the shaft portion 3a of the driven roller 3 is fitted is provided at one end thereof. On the other end side, a receiving part 12 is formed as a pressing means supporting part for receiving the spring 4 as a pressing means fitted between the spring seat 9 formed on the side plate 1. A fulcrum hole 13 is formed between the bearing portion 11 and the receiving portion 12 so that the fulcrum shaft 6 implanted in the side plate 1 by caulking or the like is fitted. The bearing member 10 is a resin molded product,
The material is preferably polyacetal when used in a place where it is hardly affected by heat, and PPS or the like is preferable when used in a place where heat resistance is required.

The bearing member 10 is rotatable around the fulcrum shaft 9 by fitting the fulcrum hole 13 to the fulcrum shaft 9 of the side plate 1. At this time, E cut to the fulcrum shaft 6
By fitting the E-shaped ring 14 into the mold ring groove 6a,
The thrust direction of the bearing member 10 is regulated.
As shown in FIG. 2, the bearing member 10 is supported by the spring 4 inserted between the spring seat 9 and the receiving portion 12.
, A rotational force in the counterclockwise direction is urged, and the driven roller 3 is pressed against the drive roller 2 by the elastic force thereof, and is held at that position. The thrust direction of the driven roller 3 is regulated by an E-ring 15 fitted in an E-ring groove 3b formed in the shaft 3a.

[0016] The sheet conveying device thus configured is
Since the driven roller 3 is pressed against the driving roller 2 utilizing the principle of leverage, problems such as a shift in the axial center due to a slight difference in the shape of the left and right bearings and the like are likely to occur.

Therefore, in the present embodiment, when the bearing member 10 is divided by a plane orthogonal to the axial direction of the roller passing through the center, the divided part is formed to be symmetrical. That is, the bearing member 10 is formed in a shape such that the left and right portions are symmetrical when divided into right and left parts by a center line in the width direction. As the bearing member 10 formed in such a shape, the same member common to both ends of the driven roller 3 can be used without distinction between right and left bearing members.

[0018] The sheet transport insertion and placement configured as described above is as follows.
Since the same bearing member 10 is used to rotatably support the two shaft portions 3a of the driven roller 3, it is difficult for subtle differences due to dimensional accuracy in the processing of parts to occur, and the deviation of the axis of the driven roller 3 and the like. Can be prevented.

The bearing member 10 can be made by injection molding. If a plurality of dies are used at this time, there is a possibility that a slight change in the shape will occur if the dies change. . Therefore, the left and right bearing members 1 of the driven roller 3
For 0, it is preferable to use the one molded from the same mold, and the bearing member 10 is provided with, for example, a cavitation number or the like for each mold so that it can be easily determined. ing.

With this configuration, it is possible to easily prevent the right and left bearing members 10 of the driven roller 3 from being formed from different molds. In the above embodiment, the bearing member 10 is supported by the side plate 1.
Then, an E-shaped ring 14 for regulating the thrust direction of the bearing member 10 is generated. In addition, since the fulcrum shaft 6 is also formed with an E-shaped groove 6a, there is a problem that the component cost is increased. Further, the assembling work is not easy, and the cost is increasing.

The embodiment shown in FIG. 3 solves the above-mentioned problem. The left and right bearing members 20 are shown, but only the left side plate 1 is shown. In the present embodiment, the left and right bearing members 20 are used separately, but the basic configuration of the drive roller 2 is the same.

In FIG. 3, one end of the bearing member 20 is provided with a cylindrically protruding bearing portion 21 for rotatably supporting the shaft portion 3a of the driven roller 3, and a receiving portion for receiving the spring 4 on the other end side. 22 are formed. A fulcrum boss 23 formed as a cylindrical boss is provided between the bearing portion 11 and the receiving portion 12. In this case, the bearing member 20 is a resin molded product, and a locking claw 24 that regulates the thrust direction of the bearing member 20 by utilizing the elasticity of the resin is provided at the tip side of the fulcrum boss 23 by about 180 degrees. It is formed in the place.

The side plate 1 has an arc-shaped elongated hole 8 for a bearing 21 supporting the driven roller 3, a circular support hole 17 for rotatably supporting a bearing member 20, and a spring 4.
A hole-shaped spring seat 9 or the like on which the seat is seated is formed. A ring 18 having the same diameter as the support hole 17 is fixed to the side plate 1 on the surface opposite to the side on which the bearing member 20 is mounted,
The depth of the support hole 17 is set to be several millimeters, for example, about 5 mm. When the fulcrum boss 23 is inserted into the ring 18 as shown in FIG.
Is locked, the bearing member 20 is supported by the side plate 1 almost without backlash.

[0024] The sheet conveying device thus configured is
When the fulcrum boss 23 of the bearing member 20 is inserted into the support hole 17 of the side plate 1, the locking claw 24 is locked by the ring 18, so that the bearing member 20 can be mounted on the side plate 1. Further, the driven roller 3 is supported only by inserting the shaft 3a into the bearing 21, so that the E-ring can be omitted. Therefore, the assembling work of the bearing member 20 and the driven roller 3 can be performed very easily.

As shown in FIG. 5, a wall 21a for regulating the position of the end of the driven roller 3 is formed in the cylindrical bearing portion 21 so that the driven roller 3 in the thrust direction can be formed. Positioning can be done.

Further, as shown in FIGS. 3 and 4, the engaging claw 24 which regulates the thrust direction of the bearing member 20 has a protruding portion 25 having a shape which is pinched by hand as a release assisting portion for assisting removal at the tip. Is provided. When this projection is at least longer than the cylindrical fulcrum boss 22, operability is improved, and it is not necessary to use a tool.

[0027]

According to the first aspect of the present invention, even if one roller is pressed against the other roller utilizing the principle of leverage, the bearing members at both ends have the same shape. Therefore, it is possible to prevent a left-right difference in the pressing force due to a subtle difference in the shape of the left and right bearing members and a displacement of the axis, and to prevent the image from being bent straight due to the skew of the transfer paper.

According to the second aspect of the present invention, the bearing member is distinguished from the injection-molded mold by marking the identification mark, so that the bearings formed by different molds and having slightly different shapes are formed at both ends. Since it can be prevented from being used at the same time, it is possible to prevent the left and right difference of the pressing force and the displacement of the axis
The image does not bend in a straight line due to the skew of the transfer paper.

According to the third aspect of the present invention, even in a type in which one roller is pressed against the other roller using the leverage principle, the positioning of the bearing member in the thrust direction is performed by utilizing the elasticity of the resin. By providing the positioning portion for performing, the number of parts and the cost can be reduced without the need for a fulcrum shaft or a retaining ring.

According to the configuration of claim 4, in addition to the effect of claim 3, by providing at least two claw portions for the positioning portion, the fulcrum portion when the spring is pressed by the spring is provided. Since the bearing member can be prevented from falling due to backlash,
It is possible to prevent the loss of the pressing force and the displacement of the roller axis.

According to the configuration of claim 5, in addition to the effect of claim 3, the claw portion has a holding portion for assisting removal, so that the roller can be removed without using a tool. be able to.

According to the sixth aspect of the invention, in addition to the effect of the third aspect, since the roller positioning portion for regulating the thrust direction of the roller is provided integrally with the bearing, only the bearing is set. Thus, the positioning of the roller in the thrust direction can be performed at the same time, and the cost of cutting the groove in the shaft and the cost of the retaining ring can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a sheet conveying device according to the present invention.

FIG. 2 is an explanatory sectional view showing a bearing member of a driven roller of the apparatus of FIG. 1;

FIG. 3 is an exploded perspective view showing another embodiment of the sheet conveying device according to the present invention.

FIG. 4 is an explanatory sectional view of a fulcrum in a bearing member of the device of FIG. 3;

FIG. 5 is an explanatory cross-sectional view of a driven roller bearing portion in the bearing member of the device of FIG. 3;

FIG. 6 is a side view illustrating an example of a conventional sheet conveying apparatus.

7 is an exploded perspective view of the device of FIG.

FIG. 8 is an explanatory side view showing an example of another conventional sheet conveying apparatus.

FIG. 9 is an explanatory side view showing an example of still another conventional sheet conveying apparatus.

FIG. 10 is an exploded perspective view showing still another example of the conventional sheet conveying apparatus.

[Description of Signs] 1 side plate 2 drive roller 3 driven roller 4 spring 10, 20 bearing member 11, 21 bearing portion 12, 22 receiving portion 13 fulcrum hole 23 fulcrum boss

Claims (6)

[Claims] 1. A roller having a pair of rollers, both ends of which are rotatably supported by side plates, and pressing means for pressing one roller of the pair of rollers against the other roller, wherein a sheet is pressed by the pair of rollers. In a sheet conveying device for nipping and conveying, a bearing portion that supports the one roller, a pressing portion supporting portion that supports the pressing portion, and a pressing portion provided between the bearing portion and the pressing portion supporting portion, A bearing member having a fulcrum portion rotatably mounted on the side plate is provided, and the bearing member has a symmetrical portion when divided by a plane passing through the center thereof and orthogonal to the axial direction of the roller. A sheet conveying device characterized by the above-mentioned. 2. The sheet conveying apparatus according to claim 1, wherein the bearing member is an injection molded product, and the bearing member is provided with a mark for identifying an injection-molded mold. Sheet transport device. 3. A roller having a pair of rollers, both ends of which are rotatably supported by side plates, and pressing means for pressing one roller of the pair of rollers against the other roller, wherein the roller pair presses a sheet. In a sheet conveying device for nipping and conveying, a bearing portion that supports the one roller, a pressing portion supporting portion that supports the pressing portion, and a pressing portion provided between the bearing portion and the pressing portion supporting portion, A bearing member having a fulcrum portion rotatably mounted on the side plate, the bearing member being made of synthetic resin, and positioning the roller in the fulcrum portion in the axial direction using the elasticity of the synthetic resin; A sheet conveying device provided with means. 4. The sheet conveying device according to claim 3, wherein the positioning means provided on the bearing member is a claw locked on the side plate provided on the fulcrum, and the claw is at least. A sheet conveying device, wherein two sheet conveying devices are provided. 5. The sheet conveying device according to claim 4, wherein the claw is provided with a release assisting portion for prompting an unlocking operation. 6. The sheet conveying device according to claim 3, wherein the bearing member is provided integrally with an axial positioning portion of the one roller.