The present invention relates generally to a conveyance roller and a printing device comprising the conveyance roller. The conveyance roller may be for example intended to convey a recording medium.
In conventional printing devices, for example, a conveyance roller is configured by forming an elastic member enclosing a roller base body. The roller base body has a cylindrical shape and is mounted on a shaft body. Typically, the conveyance roller includes a rotation stopper on the shaft body of the conveyance roller.
For example, in the section “Background Technology” of Patent Document 1, such a conveyance roller having a rotation stopper is described.
The shaft body 80 illustrated in
However, as pointed out in Patent Document 1, the elastic member 91, when cooled, contracts unevenly in a region of the protrusion with respect to a region other than the protrusion of the circumferential surface of the roller base body 81. This is due to a difference in thickness of the elastic member 91. As a result, a shape of the protrusion 82 is transferred slightly on a top surface of the elastic member 91, thus generating a protuberance 92. Further, the circularity of a cross section parallel to a y-z plane of the elastic member 91 (referred to hereinafter as a cross section) is impaired, thereby reducing conveyance precision.
Patent Document 1 discloses a structure for a conveyance roller used together with a driven roller to improve conveyance precision.
On a shaft body 83 illustrated in
There is no protrusion in a region of a circumferential surface of the roller base body 85 that opposes the driven roller 84, and the elastic member contracts evenly in this region. As a result, the elastic member is formed into a substantially perfectly circular shape the cross section of which at a circumference that contacts the driven roller 84 is acceptable.
[Patent Document 1] Japanese Patent No. 4,438,954
However, reliably stopping the rotation of the elastic member relative to roller and providing a substantially perfectly circular cross section may be difficult to accomplish with the structure taught by Patent Document 1. For example, when a deeper groove is cut to obtain a greater rotation stopping effect by means of the rotation stopper, contraction of the elastic member near the groove becomes larger, and the cross section of the roller will eventually deviate from the perfectly circular shape.
One or more embodiments of the present invention relate to a conveyance roller that can, for example, reliably stopping the rotation of an elastic member relative to the roller and provide a substantially perfectly circular cross section.
In one aspect, a conveyance roller according to one or more embodiments of the present invention may comprise a shaft body having a rotational axis, a roller base body (or simply “roller base”), which may be of cylindrical shape, and an elastic member covering the roller base body. The shaft body may comprise the roller base body. The roller base body has a center axis coinciding with the rotational axis of the shaft body. The roller base body may comprise at least one protrusion provided on at least one lateral surface other than a circumferential surface of the roller base body and covered by the elastic member. Alternatively, instead of the at least one protrusion, according to one or more embodiments of the present invention, the roller base body may comprise one or more through-holes, into which the elastic member may be inserted. The one or more through-holes may penetrate the roller base body, for example in a direction parallel to a diameter thereof. According to one or more embodiments of the present invention, the roller base body may comprise one or more radially extending through-holes, into which the elastic member may be inserted.
According one or more embodiments of the conveyance roller, the at least one protrusion is described as alternative to the at least one through-hole. However, according to one or more embodiments of the conveyance roller, the roller base body may comprise both at least one protrusion provided on at least one lateral surface other than a circumferential surface of the roller base body and covered by the elastic member, and at least one through-hole penetrating the roller base body in a direction parallel to a diameter thereof and into which the elastic member is inserted.
According to one or more embodiments of the conveyance roller, an effect of stopping the rotation of the elastic member relative to the roller can be obtained by the at least one protrusion and/or the at least one through-hole.
According to one or more embodiments, because the at least one protrusion may be disposed on the lateral surface other than the circumferential surface of the roller base body, the at least one protrusion may have various shapes and heights to stopping rotation without impairing the circular shape of a cross section of the roller. According to one or more embodiments, more than one such protrusion may be provided on the lateral surface other than the circumferential surface of the roller base body.
According to one or more embodiments, when the roller base body is provided with at least one through-hole, because a thickness of a thick portion decreases, shape irregularities in the roller base body due to contraction of the elastic member, which may for example be made of resin, can be suppressed. Since the roller base body covered by the elastic member is formed into a more accurate true cylindrical shape, the cross section of the roller at the roller base body covered by the elastic member is formed into a more accurate true circular shape.
In this manner, for example, a conveyance roller capable of providing both the effect of stopping rotation of the elastic member relative to the roller and of having a true circular-shaped cross section can be obtained.
According to one or more embodiments, the roller base body may be produced separate from the shaft body and, subsequently, the roller base body and the shaft body may be mechanically connected to each other. Alternatively, the shaft body and the roller base body may be formed in one piece.
According to one or more embodiments, at least one protrusion may be provided on at least one lateral side of the roller base body. According to one or more embodiments, the roller base body may comprise at least two protrusions, namely a first protrusion, for example provided on a first lateral surface of the roller base body, and a second protrusion, for example provided on a second lateral surface of the roller base body. The first and second protrusions are covered by the elastic member.
According to one or more embodiments, due to the one or more protrusions that may be provided on each of the lateral sides of the roller base body, a greater effect of stopping the rotation of the elastic member may be obtained.
According to one or more embodiments, the roller base body may comprise a plurality of through-holes. The plurality of through-holes may penetrate the roller base body in a direction parallel to a diameter of the roller base body and into which the elastic member may be inserted. According to one or more embodiments, a thickness between adjacent through-holes among the plurality of through-holes, a thickness between at least one of the plurality of through-holes and the circumferential surface closest to the at least one of the plurality of through-holes, and a thickness between the at least one of the plurality of through-holes and the lateral surface may be substantially equal. For example, these thicknesses may be substantially equal when they differ, at the most, by 20%, 15%, 10%, 5% or 1% from each other.
According to one or more embodiments, because the thicknesses of the roller base body may be constant, unevenness of a contraction amount of the elastic member may be further reduced, and irregularities in the shape of the roller base body due to contraction of the elastic member may be more effectively suppressed.
According to one or more embodiments, a diameter of the at least one through-hole may be less than or equal to a thickness of the elastic member at the circumferential surface of the roller base body.
According to one or more embodiments, no dent or irregularity arises on a top surface of the elastic member positioned above the at least one through-hole by the elastic member contracting toward an inside of the at least one through-hole.
According to one or more embodiments, the at least one through-hole may be partially or completely filled with the elastic member.
According to one or more embodiments, because the entirety of the through-hole may be filled with the elastic member, a greater effect of stopping rotation may be obtained.
According to one or more embodiments, the elastic member may be outsert molded on the roller base body.
According to one or more embodiments, the conveyance roller may comprise the elastic member outsert molded on the roller base body.
According to one or more embodiments, the shaft body and the roller base body may be made of the same material, such as for example a resin, or may be made of different materials. According to one or more embodiments, the elastic member may be made of an elastic resin.
According to one or more embodiments, the shaft body, the roller base body and the elastic member may each be made of a suitable material as known by one of ordinary skill in the art. The shaft body, the roller base body and the elastic member body may be also made of different materials.
According to one or more embodiments, a printing device may comprise a conveyance roller according to any of the embodiments defined above. The conveyance roller may comprise a shaft body having a rotational axis, a cylindrical roller base body, the center axis of which may coincide with the rotational axis of the shaft body, and an elastic member that may cover the roller base body. The roller base body may comprise at least one protrusion that is covered by the elastic member and that may be provided on one lateral surface of the roller base body that is not a circumferential surface of the roller base body and/or at least one through-hole that may penetrate the roller base body, for example in a direction parallel to a diameter of the roller base body and into which the elastic member may be inserted.
The conveyance roller of the present invention is capable of providing both the effect of stopping the rotation of the elastic member relative to the roller and of having a true circular-shaped cross section.
Embodiments of the present invention will be described in detail below with reference to the drawings. Each embodiment that will be described below illustrates an example of the present invention and is provided for mere illustrative purposes. However, these embodiments can be combined with each other and are not intended to be limited to the specific combinations of features disclosed herein. Also, numerical values, shapes, materials, components, disposition positions and connection modes of the components, and the like are examples and are not intended to limit the present invention.
A conveyance roller according to one or more embodiments of the present invention may be a conveyance roller comprising: a shaft body comprising a cylindrical roller base body having a center axis coinciding with a rotational axis of the shaft body, and an elastic member covering the roller base body. According to one or more embodiments, the rotation of the elastic member relative the roller base body may be stopped, while maintaining a substantially perfect circular shape of a cross section of the roller. The conveyance roller may be used, for example, for conveying a recording medium, for example in printing devices.
First, a printing device comprising a conveyance roller according to one or more embodiments of the present invention will be described, and afterward the conveyance roller will be described in detail.
A printing device 100 illustrated in
The conveyance mechanism 200 shown in
The conveyance roller according to one or more embodiments of the present invention can be used, for example, as a discharge roller of a printing device, for example the discharge roller 204 of the exemplary printing device 100. The use of the conveyance roller according to one or more embodiments of the present invention, however, is not limited to a discharge roller. According to one or more embodiments of the present invention, the conveyance roller may also be used as a pick roller or as a feed roller, for example the pick roller 202 or the feed roller 203 described above.
The conveyance roller according to one or more embodiments of the present invention will be described in detail below.
A shaft body 10 shown in
On a conveyance roller 1 illustrated in
According to one or more embodiments, because there is no unevenness on the circumferential surface of the roller base body 11, the elastic member 30 has an even thickness on the circumferential surface of the roller base body 11 and contracts evenly. As a result, a cross section of the roller at the roller base body 11 covered by the elastic member 30 can have a substantially perfectly circular shape.
Furthermore, because the protrusion 12 may be disposed on the lateral surface of the roller base body 11, any number of protrusions 12 of a shape and height suitable to stop rotation may be provided without impairing the circular shape of the cross section of the roller, thus enabling the conveyance roller to convey an object such as paper with high precision.
As a result, the conveyance roller according to one or more embodiments can convey an object such as paper with high precision.
An example where four protrusions 12 of a cubic shape are provided on one lateral surface of the roller base body 11 is illustrated above, but the number and the shape of the protrusions shall not be limited to this example. Several other examples where the number and the shape of the protrusions differ will be described below.
For example, as shown in each side view of
Furthermore, for example, as shown in the perspective view of
Furthermore, for example, as shown in the perspective view of
A height from the lateral surface of the roller base body 11 of these protrusions is not limited, but as an example, these protrusions may be provided at a height greater than or equal to a thickness of the elastic member 30 on the lateral surface of the roller base body 11. A higher protrusion may be provided for enhancing the effect of stopping rotation without adversely affecting the substantially perfectly circular shape of the cross section of the roller.
Furthermore, a root or base of the at least one protrusion may be greater than or equal to a height commensurate with the advantageous effect of stopping rotation and covered by the elastic member 30. The at least one protrusion may not be covered by the elastic member 30 as long as sufficient stopping of rotation is provided. In other words, only a portion of the at least one protrusion may be covered by the elastic member 30. For example, an apex of the at least one protrusion may not be covered by the elastic member.
The conveyance roller according to one or more embodiments of the present invention may also comprise one or more through-holes instead of the one or more protrusions to provide both stopping of rotation of the elastic member relative the roller base body and a substantially circular-shaped cross section of the roller.
When one or more through-holes are defined in the roller base body, as for example in the exemplary embodiments described below, the conveyance roller 1 according to one or more embodiments may have a regular shape due to the reduction of the irregularities in the shape that may arise due to contraction of the resin in the roller base body 11 having the comparatively large thickness, and may comprise an accurately formed roller base body 11 having a substantially perfectly cylindrical shape.
Next, a conveyance roller in accordance with one or more embodiments of the present invention will be described.
A conveyance roller may comprise a shaft body 20 as illustrated in
Providing at least one through-hole 22 in the roller base body 21 can reduce the thickness of the roller base body 21, thereby preventing irregularities in the shape of the roller base body 21, which are caused in the prior art rollers by uneven contraction of the resin, without requiring adjustment of the molding parameters.
In
For example, the through-holes 22 may be provided such that these thicknesses a, b, c are substantially equal to each other. By doing so, because the material distribution of the roller base body 21 becomes uniform, unevenness due to a contraction of the resin can be further reduced, and any irregularity of the shape of the roller base body 21 due to a contraction of the resin can be more effectively suppressed.
According to the exemplary conveyance roller 2 illustrated in
To stop rotation between the elastic member 30 and the roller base body 21, the elastic member 30 may enter the at least one through-hole 22 to a limited depth only, or may completely fill the at least one through-hole 22.
According to one or more embodiments, the roller base body 21 in which the at least one through-hole 22 is defined, when covered by the elastic member 30, has a more accurate truly cylindrical shape. As a result, the cross section of the roller at the roller base body 21 covered or enclosed by the elastic member 30 can be formed into a substantially perfectly circular shape. Moreover, the elastic member 30 at least partially extending into the at least one through-hole 22 can stop rotation.
To avoid a dent or any other irregularity in the surface of the elastic member 30 in the area where the elastic member 30 extends into the at least one through-hole 22, the at least one through-hole 22 may have a small diameter. For example, the diameter of the at least one through-hole 22 may be smaller than the thickness of the elastic member 30 at the circumferential surface of the roller base body 21.
However, even when the diameter of the at least one through-hole 22 is small, by completely filling the at least one through-hole 22 with the elastic member 30, and fitting the elastic member 30 in the entirety of the at least one through-hole 22, improved rotation stopping may be obtained. Moreover, even when the diameter of the at least one through-hole 22 is small, by providing multiple through-holes 22, improved rotation stopping may be obtained, thus enabling the conveyance roller to convey an object such as paper with high precision.
As a result, the conveyance roller according to one or more embodiments can convey the object such as paper with high precision.
Although
For example, as shown in the perspective view of
Furthermore, for example, as shown in the perspective view of
Furthermore, for example, as shown in the perspective view of
Furthermore, for example, as shown in the perspective view of
Furthermore, for example, as shown in the perspective view of
The present invention is not limited to the above-described embodiments. To an extent that they do not depart from the scope of the claims, embodiments based on various modifications of the features of the exemplary embodiments described therein or on various combinations of the different embodiments described therein are also possible.
According to one or more embodiments of the present invention, the conveyance roller may be applied widely to various types of conveyance mechanisms for conveying an object, such as a conveyance mechanism of a printing medium in a printing device, for example.
1, 2, 8 Conveyance roller
10, 20, 80, 83 Shaft body
11, 21, 81, 85 Roller base body
12 to 14, 82 Protrusion
22 to 27 Through-hole
30, 91 Elastic member
84 Driven roller
86 Groove
87 Step
92 Protuberance
100 Printing device
101 Enclosure body
102 Feed and discharge paper tray
103 Control unit (or controller)
200 Conveyance mechanism
201 Frame
202 Pick roller
203 Roller
204 Discharge roller
205 Motor
Number | Date | Country | Kind |
---|---|---|---|
2013-258888 | Dec 2013 | JP | national |