JP3774676B2 - Roller member, sheet conveying apparatus using the same, and image processing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a roller member for contacting a sheet and conveying the sheet by its frictional force, and in particular minimizes sheet skew and conveyance speed change for any size sheet, The present invention also relates to a roller member capable of conveying a sheet while preventing wrinkles on the sheet, a sheet conveying apparatus using the roller member, and an image processing apparatus such as an electrophotographic copying machine, a printer, a word processor, and a facsimile apparatus.
[0002]
[Prior art]
In an image forming apparatus such as a copying machine or a laser beam printer, at least one of a pair of conveying rollers used for conveying a sheet or the like is generally around a shaft having high hardness (hereinafter referred to as “shaft body”) such as metal. It is composed of a composite roller on which an elastic body layer such as rubber is formed.
[0003]
As shown in FIG. 9, the pair of transport rollers are pressed against each other by a compression force P by a pressure spring or the like at both ends of the shaft, and form a contact region called a nip by deformation of a material having low hardness such as rubber. The sheet is nipped by both rollers in the nip region and is conveyed by the rotation of the conveying roller pair.
[0004]
[Problems to be solved by the invention]
However, in the transport state, the shaft body of the transport roller is bent by a compressive load applied to both end portions of the roller, and the bending of the shaft body brings both rollers closer to each other at the end portion than the central portion in the roller axial direction. Therefore, the rubber or the like at the end portion is deformed more than the center portion, and the nip width is made uneven in the axial direction.
[0005]
The non-uniformity of the nip width and the nip pressure in the roller axis direction is a factor that causes a difference in the peripheral speed of each part of the roller, such as V1, V2, and V3 shown in FIG. It becomes.
[0006]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to eliminate the distortion amount in the rotational direction of the elastic layer of the roller member and the non-uniformity in the axial direction of the nip width with a simple structure. A roller member that suppresses skewing, leaning, speed change, and the like, and a sheet conveying device and an image forming apparatus including the roller member are provided at low cost.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a typical configuration according to the present invention is a roller member for contacting a sheet, conveying the sheet by frictional force, or separating the sheet, and supporting the sheet upright on the working surface with the sheet. And a plurality of projecting members formed at the tip of the support portion, the head portion being in contact with the sheet, and the cross-sectional shape of the support portion in the roller axial direction is a long portion and a short portion. And at least some of the plurality of projecting members are configured such that an inclination angle α formed by the long portion and the roller shaft is 0 ° <α <90 ° , The inclination angle α increases as it goes from the center to the end in the roller axis direction .
[0008]
In the above configuration, even if the roller shaft is bent and a high compressive force is applied to the end portion, and the peripheral speed of each portion in the roller axis direction is different, the protruding member in the vicinity of the nip portion and the downstream side of the nip portion causes the sheet to On the other hand, the elastic reaction force in the direction that forms α ° in the conveyance direction, that is, the direction that mitigates the adverse effect on the sheet conveyance due to the difference in peripheral speed is generated, thereby suppressing the skew of the sheet, the leaning of the sheet within the allowable value. it can.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
A first embodiment of the present invention will be described below with reference to the drawings.
[0010]
{overall structure}
First, a schematic configuration and operation of an image forming apparatus main body to which the sheet conveying apparatus of the present invention can be applied will be briefly described with reference to FIG. FIG. 6 is an explanatory diagram of the overall configuration of an image forming apparatus main body to which the sheet conveying apparatus can be applied.
[0011]
In response to an image signal sent from a host computer (not shown), a laser beam whose intensity is modulated from a laser scanner 18 provided in the apparatus main body 10 is irradiated to a pre-charged photosensitive drum 15 through a mirror 19, and the drum An electrostatic latent image is formed on 15. Next, the electrostatic latent image is developed by a developing unit (not shown) to form a toner image.
[0012]
On the other hand, the sheets S in the storage cassette 11 mounted at the lower part of the apparatus main body are separated and fed one by one by the feeding roller 14 and the separation pad 12, passed through the conveying roller pair 21 and 22, and then by the registration roller pair 1 and 13. The skew feeding is corrected, and the conveyance timing is adjusted to synchronize with the formation of the toner image. Thereafter, the sheet S is conveyed to the image forming unit, and the toner image on the photosensitive drum 15 is transferred to the sheet S by the transfer unit 16 and is conveyed to the fixing device 20 by the conveying belt 17. The fixing device 20 fixes the transfer toner by heating and pressing the sheet S by a fixing roller 31 incorporating a heater and a pressure roller 32 that presses the sheet S against the fixing roller 31. The image-fixed sheet is discharged to the discharge unit 27 by the conveyance roller pair 23 and 24 and the discharge roller pair 25 and 26.
[0013]
{Roller configuration of sheet conveying device}
Next, the sheet conveying apparatus according to the present embodiment will be described with reference to FIGS. FIG. 1 shows a registration roller as a conveying device, (a) is a perspective view showing details, (b) is a sectional view thereof, and (c) is an explanatory front view thereof. 2 is an enlarged explanatory view of a three-dimensional structure on the surface of the registration roller in the axial range W1 of the registration roller elastic layer, and FIG. 3 is a diagram of 3 of the registration roller surface in the axial range W2 and W3 of the registration roller elastic layer. It is an expansion explanatory view of a dimensional structure.
[0014]
As shown in FIGS. 1 (a) and 1 (b), a registration roller 1 as a roller member is formed on the outer periphery of a shaft 2 made of metal or resin, and made of EPDM, CR rubber, silicon rubber, urethane rubber or the like. The elastic body layer 3 is made of a material having low hardness, contacts the sheet S, and conveys the sheet S by frictional force.
[0015]
The elastic layer surface 3a of the registration roller 1 is finely processed. As shown in FIGS. 2 (a) and 2 (b), the base 3b not subjected to the fine processing and the fine processing are applied. A three-dimensional structure 4 that is a protruding member is formed.
[0016]
As shown in FIGS. 2A and 2B, the three-dimensional structure 4 holds a head 6 having a spherical shape (a spherical shape having a diameter R in this embodiment) at the tip, and the head 6. It is formed in a mushroom shape by the support portion 5 of a quadrangular prism built up from the elastic base portion 3b. The three-dimensional structure 4 has a height h in the range of 1 to 500 μm.
[0017]
In addition, as shown in FIG. 1C, the registration roller 1 has an overall length in the axial direction of the elastic body layer W, a range W1 located in the central portion, ranges W2 and W2 ′ located on both sides thereof, and both end portions. W3, W3 'located in
[0018]
In this embodiment, the range is W1 = W2 = W2 ′ = W3 = W3 ′ = W / 5, but the range may be equally divided or unequally divided into an arbitrary number.
[0019]
As shown in FIG. 2 (a), the support part 5 of the three-dimensional structure 4 in the range W1 located in the center of the elastic body layer axial direction range shown in FIG. 1 (c) has a long side (long part) x, It is a quadrangular prism having a rectangular shape with a short side (short part) y, and the shape of the three-dimensional structure 4 in the other ranges W2, W2 ′, W3, and W3 ′ is the same as the shape of the three-dimensional structure in the range W1. It is the same.
[0020]
In addition, as shown in FIG. 2C, in the range W1 of the central portion in the roller elastic body layer axial direction, the long side in the cross section parallel to the base portion 3b of each support portion 5 of the three-dimensional structure 4 has the same cross section. It is parallel to the center line of the roller shaft projected onto.
[0021]
On the other hand, as shown in FIG. 3 (c), the length in the cross section parallel to the elastic body base surface of the support portion 5 of the three-dimensional structure 4 in the range W2 and W3 on one side in the axial direction of the roller elastic body layer. The side forms an angle α with the center line of the roller shaft projected onto the same cross section.
[0022]
Here, the angle α in the roller elastic body layer axial range W2 is configured to be α2, the angle α in the range W3 is configured to be α3, and 0 ° <α2 <α3 <90 ° is satisfied. It is configured. That is, the angle α increases within 90 ° toward the end in the axial direction of the roller elastic layer.
[0023]
The three-dimensional structures 4 in the ranges W2 ′ and W3 ′ on the other side in the axial direction of the roller elastic layer are the three-dimensional structures in the ranges W2 and W3 and the roller elastic layer orthogonal to the roller axis, respectively. At the same time, the distance L between adjacent three-dimensional structures is configured to be equal in all ranges in the roller elastic body layer 3 while forming a symmetrical shape with the axial center cross section as a symmetry plane.
[0024]
{Sheet conveying operation}
Next, the operation of the registration roller 1 configured as described above will be described with reference to FIGS. 4A is a diagram showing a contact state between the three-dimensional structure 4 and the sheet S in the range W1 when the registration roller 1 is in the sheet conveyance state, and FIG. 4B is a top view thereof. FIG. 4C is a view in the same direction as FIG. 4B showing the elastic change of the three-dimensional structure in the range W2 and the range W3 in the same state. FIG. 5 is a conceptual perspective view when the registration rollers 1 and 13 are in a sheet conveying state. In FIGS. 4 and 5, for the convenience of explanation, the actual arrangement is displayed upside down.
[0025]
When the sheet S is conveyed by the registration roller 1, the registration roller 1 rotates in the direction of arrow A as shown in FIG. It is conveyed in the direction of arrow A by the frictional force generated in contact with the spherical head 6. At this time, even if the paper dust 7 adheres to the sheet S, the paper dust 7 does not adhere to the head 6 because it falls to the base portion 3b, and the sheet conveying force by the three-dimensional structure 4 is affected. Don't give.
[0026]
During the conveyance of the sheet, the support portion 5 of the three-dimensional structure 4 in the registration roller nip region collapses due to elastic deformation in the direction opposite to the conveyance direction of the sheet S, as shown in FIGS. It becomes the state.
[0027]
Also in the range W2 and the range W3 other than the central portion in the elastic body layer axial direction, the registration roller 1 rotates in the direction of the arrow A, and the sheet S is in contact with the head 6 of the registration roller 1 due to the frictional force generated by the arrow. In this case, in the registration roller nip region, the support portion 5 of the three-dimensional structure 4 falls along the short side as shown in FIG. The support portion 5 formed with the center line and the angle α (α2 or α3) is elastically deformed in the direction of 180 ° −α ° with respect to the conveyance direction A of the sheet S and falls. Due to the elastic reaction force generated by the individual elastic bodies, a conveying force in the direction of arrow B, which forms an angle of α ° with the roller rotation direction A, acts on the sheet S.
[0028]
In the elastic layer axial range W2 ′ and W3 ′, the B direction is a B ′ direction that is symmetric with respect to the central plane of the roller elastic layer axial direction perpendicular to the roller axis. The operation is the same as the range W2 and the range W3.
[0029]
It should be noted that due to the elastic deformation of the support portions 5 of the individual three-dimensional structures 4 in the entire range of the roller elastic body layer 3, the spherical head 6 at the tip of the three-dimensional structure becomes the sheet S in any irregularities on the surface of the sheet S. By reliably contacting, the contact area in the entire nip portion is always kept constant, and a stable conveying force can be obtained.
[0030]
Further, the compression force P by the pressure springs applied to both ends of the shaft body 2 for obtaining the frictional force necessary for conveying the sheet at the nip portion of the registration roller pair can be set lower than in the prior art. Thereby, the bending of the shaft 2 of the registration roller 1 due to the compressive force P applied to both ends of the roller can be minimized.
[0031]
Also, even if there is a difference in the peripheral speed of each part in the roller axial direction due to the deflection of the roller shaft body, it is reduced by the conveying force in the direction of arrow B due to the elastic reaction force of each three-dimensional elastic body shown in FIG. It is possible to cancel the sheet and prevent sheet skewing, wrinkling, and the like (FIG. 5 shows a conceptual diagram of the difference in conveying force related to the sheet in the registration roller axial direction when in the sheet conveying state).
[0032]
[Second Embodiment]
Next, a second embodiment of a roller having a three-dimensional structure will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the member which has the same function as embodiment mentioned above.
[0033]
In the embodiment shown in FIG. 7, the support 5 of the three-dimensional structure 4 on the registration roller elastic body layer surface 3a is changed to the rectangular column in the first embodiment, and a long axis portion (long portion) and a short axis are provided. An elliptic cylinder having a portion (short portion). Here, an angle α formed with the center line of the roller shaft projected onto the elliptical long axis in the cross section parallel to the elastic body base surface of each support portion 5 is the same as the angle α in the first embodiment. Thus, even if the cross-sectional shape of the support part 5 is an ellipse, the same effect as 1st Embodiment can be acquired.
[0034]
Furthermore, by making the support part 5 into an elliptic cylinder shape, a degree of freedom is generated in the direction in which the three-dimensional structure support part 5 falls in the nip part, and the elastic reaction force of the support part 5 optimal for sheets of various thicknesses is obtained. Can do.
[0035]
Further, since the sheet can be conveyed with a relatively low pressing force by having the three-dimensional structure 4 as described above, the elastic body layer 3 is intermittently connected to the shaft body 2 as shown in FIG. Even if configured, the same effect can be obtained at low cost without damaging the sheet.
[0036]
In the first embodiment described above, in each of the ranges W1, W2, and W3 in the elastic layer axial direction, the positional relationship of the heads 6 formed by the individual three-dimensional structures 4 formed on the surface of the elastic layer is the axial direction. In addition, the sheets are aligned in the sheet conveying direction orthogonal to the above (see FIGS. 2C and 3C), but they are not necessarily aligned in the axial direction and the sheet conveying direction (see FIG. 8). ), The same effect can be obtained. If they are not aligned, the leading edge of the sheet does not easily sink between the leading edges of the three-dimensional structure 4, and the effect of preventing damage to the leading edge of the sheet can be obtained.
[0037]
Other Embodiment
The shape of the head 6 of the protruding member may be a hemispherical shape, a disc shape, an elliptical cone shape, a spindle shape or the like in addition to the spherical shape. The shape of the support 5 may be a shape having a long cross section (long part) and a short part (short part). In addition to a rectangular parallelepiped and an elliptical column, a polygonal column, an elliptical cone, It may be a shape such as a pyramid. That is, any shape may be used as long as the elastic force varies depending on the direction of the support portion 5.
[0038]
In the above-described embodiment, the example in which the inclination angle α is changed for each of the ranges W2 and W3 has been described. However, the inclination angle α is gradually increased from the central portion in the roller axial direction without setting the range. May be.
[0039]
In the above-described embodiment, the example in which the three-dimensional structure 4 is provided on the registration roller 1 has been described. However, the roller as the sheet conveyance device according to the present invention is applicable to other sheet conveyance rollers including the registration roller pair. is there.
[0040]
In addition, it is effective to provide the above-described three-dimensional structure 4 not only for the sheet conveying roller but also for a roller member for separating the sheet.
[0041]
In the above-described embodiment, an example in which the sheet conveying apparatus is used for the image forming apparatus has been described. However, the image forming apparatus is not limited to the image forming apparatus. Of course, it can also be used in a reading device such as a scanner having reading means.
[0042]
【The invention's effect】
As described above, in the present invention, even if the roller shaft is bent and a high compressive force is applied to the end portion, and the peripheral speed of each portion in the roller axial direction is different, the protrusion in the vicinity of the nip portion and the downstream side of the nip portion. In the member, an elastic reaction force is generated in a direction that forms α ° in the conveyance direction with respect to the sheet, that is, a direction that alleviates the adverse effect on the sheet conveyance due to the difference in peripheral speed, thereby allowing the sheet to be skewed, skewed, etc. It is possible to provide a sheet conveying apparatus and an image processing apparatus that can accurately convey the sheet at low cost.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating a registration roller as a conveyance device according to a first embodiment.
FIG. 2 is an enlarged view showing a configuration of a three-dimensional structure in an axial range W1 of the registration roller elastic body layer according to the first embodiment.
FIG. 3 is an enlarged view showing a configuration of a three-dimensional structure in axial ranges W2 and W3 of the registration roller elastic body layer according to the first embodiment.
FIG. 4 is a diagram illustrating an operation of a three-dimensional structure and a sheet when a registration roller according to the first embodiment is in a sheet conveyance state.
FIG. 5 is a conceptual perspective view showing a difference in the direction of the conveying force applied to the sheet in the registration roller axial direction when the sheet is in the sheet conveying state shown in FIG. 4;
FIG. 6 is an overall configuration diagram of the image forming apparatus main body according to the first embodiment.
FIG. 7 is an enlarged view showing a configuration of a three-dimensional structure in axial ranges W2 and W3 of the registration roller elastic body layer according to the second embodiment.
FIG. 8 is a perspective explanatory view of a roller in which an elastic body layer 3 on which a three-dimensional structure 4 is formed is formed intermittently.
FIG. 9 is a conceptual perspective view showing a difference in speed at which a sheet of registration rollers is to be conveyed in a conventional conveying device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS S ... Sheet 1, 13 ... Registration roller 2 ... Shaft body 3 ... Elastic body layer 3a ... Elastic body layer surface 3b ... Base part 4 ... Three-dimensional structure 5 ... Support part 6 ... Head 7 ... Paper dust
10 ... Main unit
11… Storage cassette
12… Separation pad
14… feed roller
15… Photoconductor drum
16… Transfer means
17… Conveyor belt
18 ... Laser scanner
19 Mirror
20… Fixer
21, 22 ... Conveyance roller
23, 24 ... Conveyance roller
25, 26… discharge roller
27… discharge section
31… Fixing roller
32… Pressure roller

Claims (9)

In the roller member for contacting the sheet, conveying the sheet by frictional force, or separating the sheet,
A support portion standing on the working surface with the seat;
Having a plurality of projecting members formed at the front end of the support portion and composed of heads that can come into contact with the sheet;
The cross-sectional shape of the support portion in the roller axis direction is formed into a shape having a long portion and a short portion, and at least some of the plurality of protruding members are inclined by the long portion and the roller shaft. The angle α is configured such that 0 ° <α <90 ° ,
The roller member, wherein the inclination angle α increases from the center toward the end in the roller axial direction . In the roller member for contacting the sheet, conveying the sheet by frictional force, or separating the sheet,
A support portion standing on the working surface with the seat;
Having a plurality of projecting members formed at the front end of the support portion and composed of heads that can come into contact with the sheet;
The cross-sectional shape of the support portion in the roller axis direction is formed into a shape having a long portion and a short portion, and at least some of the plurality of protruding members are inclined by the long portion and the roller shaft. The angle α is configured such that 0 ° <α <90 ° ,
Each of the ranges is divided into a plurality of ranges in the roller axis direction so that the angle of inclination α is the same in each range, and the angle of inclination α increases from the center to the end in the roller axis direction. A roller member characterized in that an inclination angle α is set for each . The roller member according to claim 1 or claim 2, wherein the projection member is provided intermittently to the roller axis. The roller member according to any one of claims 1 to 3 , wherein a cross-sectional shape of the support portion is a rectangle having a long side and a short side or an ellipse having a long axis and a short axis. The roller member according to claim 4 , wherein the support portion has a conical shape that gradually decreases toward the head side. Projection shape roller member according to any one of claims 1 to 5, characterized in that forming a mushroom-like shape of the height 1~500μm of the projecting member. The roller member according to claim 6 , wherein a head of the protruding member has a spherical shape, a hemispherical shape, a disc shape, a conical shape, or an elliptical conical shape. The sheet conveying apparatus which conveys a sheet | seat with a roller member, It has a roller member of any one of Claim 1 thru | or 7 as said roller member, The sheet conveying apparatus characterized by the above-mentioned. 9. A sheet conveying apparatus according to claim 8 , further comprising an image forming unit for forming an image on a sheet or an image reading unit for reading an image of a sheet document, and conveying the sheet to the image forming unit or the image reading unit. A featured image processing apparatus.

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