US20080106028A1

US20080106028A1 - Pick Tire for an Image Forming Device

Info

Publication number: US20080106028A1
Application number: US11/557,240
Authority: US
Inventors: Robert Michael Meadows; Niko Jay Murrell; Kevin Neil Berry
Original assignee: Individual
Current assignee: Lexmark International Inc
Priority date: 2006-11-07
Filing date: 2006-11-07
Publication date: 2008-05-08

Abstract

The present application is directed to a pick tire for moving media sheets within an image forming device. The pick tire includes a base with an inner surface that faces towards a central opening and an outer surface that faces away. A plurality of teeth are formed on the outer surface and contact the media sheets. The plurality of teeth are integrally molded with the base. The molded construction provides for more economical manufacturing costs, better manufacturing consistency, and increased durability.

Description

BACKGROUND

Image forming devices move media sheets along a media path. The media sheets initially begin at an input area that is sized to hold a stack of sheets. Each sheet is individually picked from the stack and introduced into the media path. The media path comprises a series of roller nips guides and/or belts. The sheets move along the media path and through an imaging area where an image is transferred to the sheet. The media sheet is then either output from the device, or recirculated through a duplex path for receiving an image on a second side.
Media sheets should be moved from the input area and into the media path in a timely manner. The distance between sheets moving along the media path is preferably minimized to increase the overall throughput of the device. The device throughput is the number of media sheets that receive a toner image and are outputted from the device within a given time period. Higher throughput devices are usually preferred by users.
A pick mechanism is positioned at the input area for moving the media sheets into the media path. The pick mechanism includes a pick tire that contacts the media sheet. Rotation of the pick tire moves the media sheet from the input area into the media path. The surface of the pick tire should have an adequate coefficient of friction with the media sheet such that rotation of the tire moves the media sheet into the media path. The pick tire should not slip during rotation because this could cause the media sheet to be delayed in moving into the media path that could result in a print defect or a media feed failure. Further, the pick tire should be constructed to be durable to withstand feeding a large number of media sheets into the media path prior to demonstrating wear.

SUMMARY

The present application is directed to pick tires for moving media sheets along a media path in an image forming device. The pick tire may include a base that includes an inner surface and an outer surface. The outer surface includes a plurality of teeth that contact the media sheets. The plurality of teeth may be integrally molded with the base. The molded construction may be consistently duplicated during the manufacturing process and may be a substantial cost savings over prior non-molded designs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an image forming device according to one embodiment.

FIG. 2 is a perspective view of a pick tire according to one embodiment.

FIG. 3 is a side view of a pick tire according to one embodiment.

FIG. 4 is an enlarged partial side view of teeth extending outward from the base according to one embodiment.

FIG. 5 is an enlarged partial top view of teeth extending outward from the base according to one embodiment.

FIG. 6 is an enlarged partial top view of teeth extending outward from the base according to one embodiment.

FIG. 7 is an enlarged partial top view of teeth extending outward from the base according to one embodiment.

FIG. 8 is an enlarged partial top view of teeth extending outward from the base according to one embodiment.

FIG. 9 is a schematic diagram of a tooth extending from the base according to one embodiment.

FIG. 10 is a schematic diagram of a tooth extending from the base according to one embodiment.

FIG. 11 is a schematic diagram of a tooth extending from the base according to one embodiment.

DETAILED DESCRIPTION

The present application is directed to a pick tire for moving media sheets along a media path in an image forming device. The pick tire includes a base with teeth on an outer surface that contact the media sheets. The teeth are integrally molded into the tire. The molded construction reduces manufacturing costs, provides manufacturing consistency, and increases durability.
FIG. 1 depicts a representative image forming device, such as a printer, indicated generally by the numeral 100. The image forming device 100 comprises a main body 112 and an input area 113 holding a stack 114 of media sheets. Pick mechanism 116 move media sheets from the media stack 114 into the media path 120. Pick mechanism 116 comprises a pivoting arm 117 and a pick tire 10 that rests on the top-most sheet. As the media stack 14 is depleted, the location of the top-most sheet moves further from the beginning of the media path 120. The pivoting arm 117 pivots downward with the pick tire 11 8 remaining in contact with the top-most media sheet in the stack 114.
The input area 113 is disposed in a lower portion of the main body 112, and is preferably removable for refilling. Pick mechanism 116 picks the top-most sheet from the stack 114 and moves the sheet into the media path 120. The term “pick” refers to moving the media sheet from the media stack 114 into the media path 120. Registration nip 121 formed between rolls 122 align the media sheet prior to passing to a transport belt 123 and past a series of image forming stations 103. A print system 142 forms a latent image on a photoconductive member in each image forming station 103 to form a toner image. The toner image is then transferred from the image forming station 103 to the passing media sheet.
Color image forming devices typically include four image forming stations 103 for printing with cyan, magenta, yellow, and black toner to produce a four-color image on the media sheet. The transport belt 123 conveys the media sheet with the color image thereon towards a fuser 124, which fixes the color image on the media sheet. Exit rollers 126 either eject the print media to an output tray 128, or direct it into a duplex path 129 for printing on a second side of the media sheet. In the latter case, the exit rollers 26 partially eject the print media and then reverse direction to invert the media sheet and direct it into the duplex path 129. A series of rollers in the duplex path 129 return the inverted print media to the primary media path for printing on the second side
FIG. 2 is a perspective view of the pick tire 10 removed from the pivoting arm 117. The pick tire 10 is normally mounted to a hub (not illustrated) that attaches to the pivoting arm 117. Pick tire 10 includes an annular base 19 with an outer surface 12 that faces towards a central opening 11. Teeth 20 are positioned on an outer surface 12 and are shaped to facilitate contact with the media sheets. As illustrated in FIG. 3, pick tire 10 is substantially circular. A thickness and diameter of the pick tire 10 may vary depending upon the parameters of use and/or the material.
Historically, the teeth 10 on the outer surface 12 of the pick tires 10 were formed by a grinding process. However, grinding the teeth 20 on the outer surface 12 resulted in numerous disadvantages. A first disadvantage was the inconsistencies in the teeth 20 and the outer surface 12. Each production run from a manufacturer often resulted in pick tires 10 with different physical characteristics. More problematic was the inconsistency in pick tires 10 when using multiple different manufacturers. Another disadvantage with grinding teeth 20 was the cost of the grinding process often constituted up to half of the total cost of manufacturing the pick tire 10. A third disadvantage was the difficultly in orienting and servicing the pick tire 10 due to the small size of the teeth 20. The small size made it difficult for visual inspection and often resulted in the pick tire being mounted to the pivoting arm 117 with the teeth 20 aligned in the wrong orientation.
The pick tire 10 of the present application includes teeth 20 that are integrally molded with the base 19. This construction eliminates the grinding process required by prior pick tires. The molded pick tires 10 are less costly to manufacture with savings of up to one-half the overall cost of the pick tire 10. Molding further increases quality and consistency because the dimensions of the pick tire 10 are controlled by a mold instead of a separate, individualized grinding process. Further, the molded pick tires 10 are easier to assemble and service because the orientation is easier to determine or is inconsequential. In one embodiment, an insignia 13 is molded into the side of the base 19 to indicate the orientation of the teeth 20.
FIG. 4 illustrates a partial side view of a section of teeth 20 extending outward from the outer surface 12 of the base 19. Each tooth 20 includes first and second sides 21, 22 and a tip 23. Gaps 24 are positioned between the adjacent teeth 20 in one embodiment, an insignia 13 is positioned on the side of the base 19 to indicate the orientation of the pick tire 10 when mounted on the pivoting arm 117. In one embodiment, the insignia is integrally molded with the base 19.
FIG. 5 illustrates a partial front view of a section of the pick tire 10. In this embodiment, the teeth 20 extend across the width of the base 19. Each tooth 20 forms a row across the width and the teeth 20 are oriented in a substantially parallel arrangement. In this embodiment, each of the teeth 20 includes substantially the same shape and size.
FIG. 6 illustrates one embodiment with the teeth 20 including different shapes and sizes. Further, the teeth 20 are positioned in a non-parallel arrangement causing the gaps 24 to be of varying size. This embodiment also features the width of the teeth 20 being less than the base 19. In another embodiment, one or more of the teeth 20 include a width to extend across the base 19 and the remaining teeth 20 including a smaller width than the base 19.
Teeth 20 may be aligned in a lateral orientation as illustrated in FIGS. 5 and 6. In another embodiment as illustrated in FIG. 7, teeth 20 are aligned in a longitudinal orientation. Teeth 20 may extend around the entire circumference of the tire 10, or a limited length. Gaps 24 may be positioned between the teeth 20 and may include lateral gaps 24a and longitudinal gaps 24b. FIG. 8 illustrates another embodiment with teeth 20 of various orientations. The teeth 20 may include different angular arrangements.
The outer surface 12 may further be textured to provide an increased grip on the media sheets. The texture may be on a limited section of the outer surface 12, or across substantially the entirety of the outer surface 12. In one embodiment, the teeth 20 are textured. In another embodiment, the gaps 24 are textured.
The teeth 20 may extend outward at a variety of angles from the outer surface 12. FIG. 9 schematically illustrates a tooth 20 extending outward from the outer surface 12. Tooth 20 extends outward at an angle a that is formed between a radius 30 from the center C of the base 19 and a centerline 39 of the tooth 20 FIG. 10 illustrates another embodiment with the tooth 20 extending directly outward from the outer surface 12. The direct extension causes the angle a to be substantially zero with the radius 30 extending through the tip 23. FIG. 11 illustrates an embodiment with a negative angle a. FIGS. 9-11 schematically illustrate a single tooth 20 extending outward from the outer surface 12. It is understood that multiple teeth 20 extend outward from the outer surface 12. In one embodiment, each of the teeth 20 is aligned at substantially the same angle a. In another embodiment, two or more of the teeth 20 are aligned at different angles α.
The tip 23 of each tooth 20 may include a variety of shapes. FIG. 4 illustrates one embodiment with a rounded tip 23. FIG. 10 illustrates another embodiment with a pointed, angular tip 23. FIG. 11 illustrates yet another embodiment featuring a substantially flat tip 23 in one embodiment, each tooth 20 includes tips 23 that are substantially the same. In another embodiment, two or more of the tips 23 include different shapes.
In one embodiment, the pick tire 10 including the base and teeth 20 are formed by compression molding. The molding material is initially placed in a mold cavity. The mold cavity and/or the molding material may be preheated prior to placement of the material within in the cavity. After the material is inserted, the cavity is closed and pressure is applied to force the material throughout the mold. The pressure ensures that the material completely fills the teeth. Pressure and heat may be applied to the mold cavity during the molding process until the molding material is cured. After curing, the pick tire 10 is removed from the mold. The pick tire 10 with the molded teeth 20 may be substantially similar to the previous pick tires that require a secondary grinding operation.
The pick tire 10 may be constructed from various materials including a rubber composition that includes isoprene rubber, at least one ozone-resistant rubber such as EPDM, and a rubber curing system substantially soluble in the mixture of the isoprene rubber and ozone-resistant rubber. The rubber composition may also include an effective amount of a mild antioxidant such as hindered phenols, hindered bisphenols, hydroquinolines, and mixtures thereof. Various compositions are disclosed in U.S. Pat. No. 5,932,313 herein incorporated by reference.
The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein

Claims

1. A pick tire for an image forming device comprising:

an annular base with an inner surface facing towards a central opening and an outer surface;

a plurality of teeth formed on the outer surface;

the plurality of teeth being integrally molded with the base.

2. The pick tire of claim 1, wherein each of the plurality of teeth are substantially identical.

3. The pick tire of claim 1, wherein each of the plurality of teeth include a leading and trailing side and a tip.

4. The pick tire of claim 1, wherein each of the plurality of teeth are aligned in a parallel arrangement about the outer surface.

5. The pick tire of claim 1, wherein the plurality of teeth are aligned in a longitudinal arrangement.

6. The pick tire of claim 1, wherein at least two of the plurality of teeth include different shapes.

7. The pick tire of claim 1, wherein the plurality of teeth are evenly spaced around the outer surface with a gap between each of the plurality of teeth being substantially equal.

8. The pick tire of claim 1, further including an insignia integrally molded with the base to indicate the orientation of the plurality of teeth.

9. The pick tire of claim 1, wherein a geometry of the plurality of teeth are substantially similar to surface configurations obtained by a secondary grinding operation.

10. A pick tire for an image forming device comprising:

a base including an outer surface and an inner surface, and

a plurality of teeth being integrally molded into the outer surface of the base, the plurality of teeth being arranged in rows along the outer surface of the base and each including first and second sides that terminate at a tip.

11. The pick tire of claim 10, wherein a width of the plurality of teeth and the base being substantially equal such that the plurality of teeth extend across the base.

12. The pick tire of claim 1 0 further comprising gaps positioned between a first tooth and a second tooth of the plurality of teeth.

13. The pick tire of claim 10, wherein a geometry of the plurality of teeth are substantially similar to surface configurations obtained by a secondary grinding operation.

14. The pick tire of claim 10, further including an insignia integrally molded with the base to indicate the orientation of the plurality of teeth.

15. A pick tire for an image forming device comprising:

a base with an inner surface facing towards a central opening and an outer surface;

a first tooth extending across a width of the outer surface; and

a second tooth extending across a width of the outer surface;

the first tooth and the second tooth being integrally molded into the base.

16. The pick tire of claim 15, wherein one of the first and second teeth include a width that is less than the base.

17. The pick tire of claim 15, wherein the first tooth is substantially parallel with the second tooth.

18. The pick tire of claim 15, wherein the first tooth includes a different shape than the second tooth.

19. The pick tire of claim 15, wherein each of the first and second teeth extend outward from the base at substantially the same angle.

20. The pick tire of claim 15, further including a lateral gap positioned between the first and second teeth and a longitudinal gap positioned between the first and second teeth.