JP3529508B2 - Press roller - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure contact roller for pressing a sheet-like material against a conveying roller.

[0002]

2. Description of the Related Art Generally, a printing paper of a facsimile, a copying machine, a printer or the like is conveyed by friction with the surface of a conveying roller which is rotationally driven. In order to transmit the frictional force of the transport roller to the print sheet with high efficiency, a pressure contact roller for pressing the print sheet against the transport roller is arranged so as to be elastically contactable toward the surface of the transport roller.

As an example of such a pressure contact roller, Japanese Utility Model Publication No. 4-47165 discloses that a bearing member that rotatably supports the roller can be slid linearly along a direction orthogonal to the paper surface of the printing paper. Japanese Patent Application Laid-Open No. 2004-242242 discloses a structure in which a coil spring supports the housing and elastically urges the coil spring.

[0004]

SUMMARY OF THE INVENTION The above-mentioned conventional type has a roller so that the diameter line of the roller and the axis line of the coil spring are substantially in series along the sliding direction of the bearing member (displacement direction of the roller). The positional relationship with the coil spring is defined. For this reason, the supporting portion of the coil spring tends to protrude, and the dimension of the roller in the displacement direction tends to increase. It is conceivable to arrange the coil spring and the roller in parallel to the paper surface of the printing paper by devising the shape of the bearing member, but in this case,
Since the amount of deviation between the vector of the biasing force of the coil spring and the displacement vector of the roller becomes large, it becomes difficult to ensure the smoothness of sliding of the bearing member.

[0005]

SUMMARY OF THE INVENTION In order to solve the inconvenience of the prior art and to provide a pressure contact roller which can reduce the dimension in the displacement direction without impairing the smoothness of the displacement motion, the present invention is provided. In this case, the roller support member has a shaft member (3) pivotally supporting the roller (2) and an open surface on one side.
A pair of boxes that are substantially box-shaped and that are orthogonal to the axis of the shaft member.
Both ends of the shaft member in the axial direction are sandwiched between the facing surfaces of the wall (side wall 17).
And a case body (4) for supporting the shaft member so as to be displaceable in a direction to bring the shaft member toward and away from the open surface, and to attach the base end portion to the case body and to play the same.
The end portion is locked to the shaft member and intersects with the axis line of the shaft member.
The roller is elastically biased in the radial direction by means of a cantilever spring (28) extending in the opposite direction. Particularly, the structure of the shaft member includes a shaft portion (7) which is inserted into the center hole (6) of the roller, and side plate portions (8) which are slidably engaged with the mutually facing surfaces of the pair of walls of the case body, On the side plate,
The free end of the cantilever spring is engaged. The shank comprises a pair which are divided into two from the middle of that, the split end of the shaft portion, adjacent to each other protrusions having a circular cross section at symmetrical positions (9) and a hole (10) for each axis center Then, when the divided ends of the shaft portion are abutted against each other, the protrusions and the holes are fitted to each other, so that the axial center is secured and the mutual rotation is prevented at the same time.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail based on specific examples shown in the accompanying drawings.

1 to 3 show a pressure roller assembly constructed in accordance with the present invention. The pressure contact roller assembly 1 includes a cylindrical roller 2, a shaft member 3 for pivotally supporting the roller 2, a case body 4 for movably supporting the shaft member 3 in a vertical direction over a predetermined range, and a shaft. Roller 2 with member 3
And a torsion coil spring 5 for elastically urging. And each of these members is the torsion coil spring 5
Each of them is formed by injection molding using a synthetic resin material.

The shaft member 3 is divided into two parts in the axial direction and comprises a shaft part 7 which is inserted into the center hole 6 of the roller 2 and a side plate part 8 which is engaged with the case body 4. , Have the same shape as each other. At the shaft ends of the shaft portions 7 of the pair of shaft members 3, a projection 9 and a hole 10 having a circular cross section are arranged adjacent to each other at symmetrical positions with respect to the shaft center. Since the pair of shaft members 3 have the same shape, when the tips of the shaft portions 7 are abutted against each other, the protrusions 9 and the holes 10 are fitted to each other, and the axial center is secured and the shaft members 3 are secured. It is designed to be used as a detent at the same time. In addition, the pair of shaft members 3
By using the same shape, the parts can be made common and the number of parts can be reduced.

A protrusion 12 having a triangular cross section is formed at the center of the outer surface of the side plate portions 8 of the pair of shaft members 3 and has a slanted surface 11 which is a downward inner recess. And this protrusion 1
Vertical protrusions 13 having a semi-circular cross section are provided on both sides of 2. A circumferential groove 1 for engaging the free ends of the torsion coil springs 5 is provided at the axially intermediate portion of the side plate portions 8.
4 are formed. Further, on the inner surfaces of the both side plate portions 8, there are formed circumferential ridges 16 having a semicircular cross section that are in sliding contact with both axial end surfaces of the hub 15 of the roller 2.

The case body 4 is in the shape of a box with an open top. On both side walls 17, a slit 18 is formed downward from an intermediate portion in the vertical direction at the center thereof, and guide ridges 19 extending in the vertical direction are provided on both sides of the slit 18 on the inner surface thereof. Has been done. Further, the front and rear walls 20 and 21 are formed with elastic claws 24 that engage with the inner edges of the mounting holes 23 provided in the chassis 22 in order to fix the pressure contact roller assembly 1 to the chassis 22. Further, the rear wall 21 is formed with a support shaft 26 for supporting the winding portion 25 on the proximal end side of the torsion coil spring 5.

Next, an assembling procedure of the press contact roller assembly 1 will be described with reference to FIG.

First, the roller 2 is fitted on the shaft portion 7 of the shaft member 3, and then the ends of the shaft portion 7 are butted against each other so that the projections 9 and the holes 10 of both are fitted to each other. As a result, the roller 2 is pivotally supported by the shaft portion 7 with the roller 2 sandwiched between the both side plate portions 8 of the shaft member 3. In this way, since the projection 9 and the hole 10 provided at the end are fitted to each other, the shaft portion 7 is integrated even though the shaft member 3 is formed separately, and the smoothness of rotation of the roller 2 is improved. It will not be damaged. The circumferential projections 16 on the inner surface of the both side plate portions 8 are brought into sliding contact with both axial end surfaces of the hub 15 of the roller 2 to reduce the contact area and reduce the rotational resistance of the roller 2.

On the other hand, in parallel with this operation, the winding portion 25 of the torsion coil spring 5 wound symmetrically is spread on the support shaft 26 formed on the rear wall 21 of the case body 4 at the intermediate portion thereof. Open and wind. At this time, the intermediate portion 27 of the torsion coil spring 5 is attached to the inner surface of the rear wall 21 of the case body 3.
And the free ends of the cantilever portions 28 extending from both axial ends of the winding portion 25 in the direction orthogonal to the axis are engaged with the circumferential groove 14 of the shaft member 3. In this way, the shaft member 3
The constitution is composed of a shaft portion 7 which is inserted into the central hole 6 of the roller 2 and a side plate portion 8 which slides on the inner surface of the side wall 17 of the case body 4, and the free end of the cantilever portion 28 is engaged with the side plate portion 8. Therefore, even if a component force that tilts the side plate portion 8 acts on the side plate portion 8 due to the offset of the point of action of the elastic force of the torsion coil spring 5, the shaft center is held and the roller 2 rotates. Smoothness is ensured.

From this state, when the projection 12 having a triangular cross section of the side plate portion 8 is pushed between the inner surfaces of the side walls 17 by using the guide projection 19 extending vertically on the inner surface of the side wall 17 of the case body 4 as a guide. Case body 4 pushed away by slope 11
Side walls 17 of the side walls are elastically deformed outward, and the protrusions 1 are formed between the inner surfaces of the side walls.
Accept 2. When the protruding end of the protrusion 12 reaches the upper end of the slit 18 at the center of the side wall, the side wall 17 is restored, the protrusion 12 is locked to the upper edge of the slit 18, and the shaft member 3 supporting the roller 2 is removed from the case body 4. It will not come out. Here, since the cantilever portion 28 of the torsion coil spring 5 is flipped upward in the natural state by the torsional elastic force of the winding portion 25, the free end of the cantilever portion 28 is engaged with the circumferential grooves 14 of the pair of shaft members 3. By pushing the shaft member 3 into the case body 4 in the worn state, the roller member 2 is pushed together with the shaft member 3.
Will be biased upward. The side plate 8
Since the vertical protrusion 13 extending on the outer surface of the sliding contact the inner surface of the side wall 17 of the case body 4, the contact area is reduced and sliding resistance is reduced.

When the pressure contact roller assembly 1 thus assembled is pushed into the mounting hole 23 of the chassis 22, the elastic claws 24 formed on the front and rear walls 20 and 21 of the case body 4 are bent inward and mounted. Enter the hole 23. And the bullet claw 2
When the free end of No. 4 reaches the back side of the chassis 22, the elastic claw 24
Is restored outward to be engaged with the chassis 22.

The roller 2 of the pressure contact roller assembly 1 assembled to the chassis 22 in this manner presses the printing paper P against the surface of the conveying roller R by the elastic force of the torsion coil spring 5.

In the above embodiment, the structure of the cantilever spring in which the end portion of the torsion coil spring is extended is adopted, but the present invention is not limited to this, and the wire spring or the plate whose base end is fixed is used. A cantilever spring can be formed by a spring.

[0018]

As described above, according to the present invention, the roller support shaft and the roller are provided separately, and the shaft member provided with the support shaft is directly elastically urged by the cantilever spring. This is very effective in reducing the dimension of the assembly in the displacement direction of the roller and ensuring the smoothness of rotation of the roller.

[Brief description of drawings]

FIG. 1 is a side view of the device of the present invention.

FIG. 2 is a top view of the device of the present invention.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is an exploded perspective view of the device of the present invention.

[Explanation of symbols]

1 Pressure contact roller assembly 2 rollers 3 shaft members 4 case body 5 torsion coil spring 6 center hole 7 Shaft 8 Side plate 9 protrusions (circular cross section) 10 holes 11 slopes 12 protrusions (triangular cross section) 13 Vertical ridges 14 circumferential groove 15 hubs 16 Circumferential ridge 17 Side wall 18 slits 19 Guide ridge 20 front wall 21 rear wall 22 chassis 23 mounting holes 24 bullet firing claws 25 winding part 26 Support shaft 27 Middle part 28 Cantilever

Continuation of the front page (56) Reference JP-A 64-58982 (JP, A) JP-A 7-68870 (JP, A) JP-A 6-328797 (JP, A) Actual development Sho-55-82238 (JP , U) Actually open 63-65643 (JP, U) Actually open 1-137937 (JP, U) Actually open 6-45955 (JP, U) Actually open 1-139555 (JP, U) Actually open 61-102545 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B65H 5/06

Claims (3)

(57) [Claims] 1. A sheet-like object is conveyed, comprising: a roller; a supporting member for supporting the roller so as to be rotatable and radially displaceable; and a biasing means for elastically biasing the roller in the radial direction. a pressure roller for pressing the roller, the support member has a shaft member for pivotally supporting the roller, whereas
Has a substantially box-like shape with an open surface and has a shaft of the shaft member.
Between the facing surfaces of the pair of walls orthogonal to the line, the axial direction of the shaft member
A case body that holds the opposite ends so as to be displaceable in a direction in which the shaft member is brought into contact with and separated from the open surface , and the resilient urging means has a base end portion. Attached to the case body
And the free end of the shaft member is locked to the shaft member.
A pressure contact roller comprising a cantilever spring extending in a direction intersecting with the axis of the material . 2. The shaft member includes a shaft portion that is inserted into a center hole of the roller and a pair of walls of the case body that are opposed to each other.
The pressure contact roller according to claim 1, wherein the pressure contact roller comprises a side plate portion that slides on a facing surface, and the free end of the cantilever spring engages with the side plate portion. 3. The shaft member is composed of a pair that is divided into two parts from the middle of the shaft part, and a projection and a hole having a circular cross section are formed at the split ends of the shaft part at symmetrical positions with respect to the center of the shaft. They are arranged adjacent to each other, and when the divided ends of the shaft portion are butted against each other, the respective projections and holes are fitted to each other, and the axial center is secured and the mutual rotation is prevented at the same time. The pressure roller according to claim 2.