SYSTEM FOR GUIDING MEDIA IN AN IMAGING APPARATUS

Abstract

A guiding system for diverting media from an input media path to an output media path in an imaging system eliminates marking and curling of media. The system employs a drive roll, an idling belt carried on one or more idler rolls, and a release roll. The idling belt presses media onto the drive roll, eliminating the relative motion between media and the drive roll and hence avoiding marking. The penetration of the release roll into the drive roll controls curling of media.

Description

TECHNICAL FIELD

The presently disclosed embodiments relate to image-forming devices, such as printers, copiers, and similar imaging apparatus, and more particularly, to devices that guide media within an imaging system.

BACKGROUND

An image-forming apparatus, such as a printer, a fax machine, or a photocopier, includes devices for directing sheet media along a media path. Conventionally, imaging devices employ baffles, diverters, rollers, or similar devices to perform that task. A media path generally begins with an input section for introducing media and includes a transfer area where media receives an image, and it may further include an output section where sheets exit from the image-forming apparatus.

Media rounding a bend in a media path are typically subjected to two types of damage—marking and curl. Marking refers to undesired spots or lines on media surface caused by the relative motion of media against a guiding device and the contact pressure between them. Curl, as the name suggests, is a deformation resulting in a loss of flatness of a media sheet.

Known sources of curl, for example, are devices employed to fix toner images formed on sheets in the image-forming apparatus. Most imaging devices, such as copiers and printers, employ a pair of rollers to perform the fixing operation employing pressure and heat. To supply sufficient heat to the toner image, a prescribed nip is formed between the rollers and satisfactory fixing proceeds by passing the sheet through this nip. After that operation, however, the sheet may exhibit curl imparted by the rolls. Another known source of curl is a change in humidity. Whatever the cause, curl renders media susceptible to deformation and causes jamming during sheet transfer.

One approach to avoiding marking and curl aims to ensure that all changes of direction in the media path occur over relatively large diameters. One example, in equipment processing a variety of different media, specifies that all changes of media path direction occur on turning radii of at least 150 mm. While measures in that direction can help control marking and curl, those solutions increase machine size and cost, detracting from these solutions' attractiveness.

Direct measures aimed at reducing marking and curl have also been attempted. One approach subjects sheets to “reverse curl,” in an operation that seeks to deliberately impart curl, but in an opposite direction to the prevailing direction of curl damage. For example, sheets curling toward the printed side can be straightened by imparting a curl in the opposite direction, toward the blank side.

Present damage control techniques have been effective for only a narrow range of media weights, however. Specific implementations of reverse curl techniques, for example, are not reliable across a spectrum of media weights. Typically, these techniques are effective for only a small range of media weights, and any curling of media outside this small range is not uniformly effective. Heavyweight, stiff, and coated media are especially sensitive to both types of damage. Existing adjustable devices may impart curl on a large range of media weights, though they are typically quite expensive. For example, the IGEN4 imaging system, commercially offered by Xerox Corporation, employs an adjustable decurler that varies the nip pressure to impart curl on media with densities ranging from 60 gsm to 350 gsm.

Improved image quality and increased speed of image-forming devices has increased the variety of media run on them. Thus, there remains a need to provide compact and inexpensive image-forming devices for sensitive types of media. Further, the image-forming devices require a media diverting system, preventing marking and curl.

SUMMARY

The present disclosure describes an apparatus for diverting media from an input media path to an output media path in an imaging system. The apparatus employs a drive roll, an idling belt carried on one or more idler rolls, and a release roll. The idler belt is in contact with the drive roll between an input nip, which accepts media from the input media path, and the output nip, where media is output to the output media path. A release roll, also an element of the diverter belt assembly, penetrates into the drive roll. As a result of the cooperative action between the drive roll and the idling belt, the media and the surface of the drive roll have identical velocities.

Certain embodiments include apparatus for diverting media from an input media path to an output media path in an imaging system. The apparatus employs a drive roll, the surface of which is formed of a resilient material. Further, the apparatus includes an idling belt, carried on one or more idler rolls and a release roll, in contact with the drive roll. The idling belt is configured to be driven solely by interaction with the drive roll, so that no relative motion exists between contacting points on the drive roll and the idling belt. The release roll, formed of a material harder than the material of the drive roll, is adjustably positioned to penetrate into the drive roll to a predetermined depth. The idling belt makes contact with the drive roll between an input nip, located for accepting media from the input media path, and an output nip.

Another embodiment includes a method for diverting a media path from an input media path to an output media path in an imaging system. The method involves receiving media from the input media path. A drive roll holds media by employing an idling belt carried on one or more idler rolls and eliminates relative motion between media and media path surfaces formed by the contact of the idling belt and the drive roll. The method further involves conveying media a predetermined angular distance around the drive roll to an output nip point defined by the drive roll and a release roll. The release roll is configured to penetrate the drive roll by an adjustable amount, imparting a reverse curl to the media, which is then released.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures described below set out and illustrate a number of exemplary embodiments of the disclosure. Throughout the drawings, like reference numerals refer to identical or functionally similar elements. The drawings are illustrative in nature and not drawn to scale.

FIG. 1 illustrates an exemplary embodiment of a media guiding system for diverting media.

FIG. 2 illustrates a flowchart of an exemplary method for diverting media in a media guiding system.

DETAILED DESCRIPTION

The following detailed description is made with reference to the figures. Exemplary embodiments are described to illustrate the subject matter of the disclosure, not to limit its scope, which is defined by the appended claims. Those of ordinary skill in the art will recognize a number of equivalent variations in the description that follows.

Overview

The present disclosure describes an apparatus and method for diverting media from an input media path to an output media path in an imaging system. Arrangement of the apparatus eliminates marking and curl in media rounding a bend in media path. The apparatus employs a diverter mechanism, including a soft drive roll and a diverter belt assembly. The diverter belt assembly operates in coordination with the drive roll and a release roll to redirect media without subjecting it to marking and curl.

This apparatus provides a low cost compact media path design with small media path radius, eliminating issues such as marking and curl of media, where these issues are a major concern for heavy, stiff, or coated media.

It should be noted that the description below does not set out specific details of manufacture or design of the various components. Those skilled in the art are familiar with such details, and unless departures from those techniques are set out, techniques, designs, and materials known in the art should be employed, and those in the art are capable of choosing suitable manufacturing and design details.

In the following description the terms “sheet” or “media” refer to sheets of paper, plastic, cardboard, or other suitable physical substrate for printing images, whether precut or initially web fed and then cut. The terms “media” and “sheet” are interchangeable and used throughout the disclosure.

DESCRIPTION OF EMBODIMENTS

FIG. 1 illustrates an exemplary embodiment of a media guiding system 100 for diverting media. The exemplary embodiment of the media guiding system 100 may be employed within a device such as a copier, a printer, a facsimile machine, or a finisher that requires media diversion without any media damages. Various other embodiments can be anticipated to address many different systems or applications in which media needs diversion.

The media guiding system 100 includes an input media path 102, a drive roll 104, a diverter idling belt 106 wrapped around multiple idler rolls, such as idler rolls 110 and 112, and a release roll 114. The drive roll 104 presses against the diverter idling belt 106, forming a guiding surface for media. Further, the media guiding system 100 includes an output media path 116.

The combination of the drive roll 104 and the diverter idling belt 106 receives media from the input media path 102 through an input nip 108. The input nip 108 is the point at which the diverter idling belt 106 makes contact with the drive roll 104. The output nip 118 is the point at which the drive roll 104 makes contact with the release roll 114. The relative position of the idler rolls 110 and 112 is arranged to facilitate contact between the diverter idling belt 106 and the drive roll 104. Thus, the diverter idling belt 106 makes contact with the drive roll 104 for an angular distance around the drive roll 104, governed by the positions of the input nip 108 and the output nip 118. From the output nip 118, sheets of media exits to the output media path 116.

The drive roll 104 has generally an elastomeric surface, with an aluminum core. Those skilled in the art will understand that a variety of materials can be used to manufacture the core of the drive roll 104, such as stainless steel, iron, or lead. In general, the surface material of the drive roll 104 is soft and spongy, such as, for example, urethane or rubber. In any event, the surface material is chosen for its characteristics, preventing marking and curl. The hardness of the surface of the drive roll 104 typically is selected to meet a number of target properties for the drive roll 104, such as the coefficient of friction, conductivity, compression set, abrasion resistance, elasticity, and cost, consistent with the type of media being conveyed. For example, the surface of the drive roll 104 may be chosen in a hardness range from 5 Shore A to 80 Shore D. Further, the drive roll 104 radius is relatively small, of about 15 mm, creating a compact arrangement. In one embodiment of the present system, the drive roll 104 is manufactured using a steel cylindrical core with a 10 mm radius, coated in an even 5 mm elastomeric layer or ‘skin,’ yielding the drive roll 104 with an outer-radius of 15 mm and having a skin formed of a material such as rubber, resin, urethane, EPDM, or other polymers. The specific material chosen for the skin exhibits properties consistent with the media types envisioned for the particular apparatus. For a general-use imaging device, an appropriate material would be a urethane polymer such as Rogers Corporation's ENDUR®-C.

The diverter idling belt 106 is a lightly tensioned belt rotating around the idler rolls 110 and 112 and the release roll 114. The diverter idling belt 106 is generally made of rubber, having sufficient coefficient of friction to carry media. The diverter idling belt 106 may have a suitable scale of durometer The media guiding system 100, as depicted includes only two idler rolls 110 and 112; those skilled in the art, however will understand that the number of rolls within the diverter belt assembly may vary based on the arrangement of the media guiding system 100 and the position of the release roll 114. The idler rolls 110 and 112 impart smooth and stable functioning of the diverter idling belt 106. The number of rolls depends on the length of the diverter idling belt 106 and the position of the release roll 114, as discussed, where the diverter idling belt 106 is dependent on the arrangement of the media guiding system 100. The diverter idling belt 106 presses incoming media onto the drive roll 104, from the input nip 108 to the output nip 118, so that the media sheet lies in contact with the drive roll for the angular distance between the input nip 108 and the output nip 118.

The release roll 114, also referred to as penetration roll, penetrates into the drive roll 104, imparting a reverse curl in media. The radius of the release roll 114 is relatively smaller than the drive roll 104, and this roll is formed from harder material than that of the drive roll 104, such as steel or hard-plastic-coated steel. For example, the IGEN4 system, noted above, uses a steel penetration roll in its decurling device. The indentation of the release roll 114 in the drive roll 104 helps control media curl, and this indentation may be set manually or automatically at different levels.

Additionally, the point on the drive roll 104 where the release roll 114 makes contact can be varied as desired, allowing the media to be held in contact with the drive roll 104 for exactly the angular distance specified by the designer. Because media exits the output nip 118 on the mutual tangent of the drive roll 104 and release roll 114, adjusting the position of the release roll 114 also has the effect of varying the output media path 116. Where desired, that feature could be used in various embodiments to allow for variable output media path 116.

Drive roll 104 is driven by conventional power means, typically an electric motor, transmitting rotational force through direct gearing or a belt drive. The diverter idling belt 106 is not driven directly, however, but rather it is powered by the drive roll 104. Interaction between the drive roll 104 and the diverter idling belt 106, in the form of friction between these components' respective surfaces, serves to drive the diverter idling belt 106. As is known in the art, the friction force present in this system depends on the respective materials, the force imparted by the diverter idling belt 106 to the drive roll 104 resulting from the layout of the idler rolls 110, 112, and the total area of contact between the components. Here, a design criterion calls for zero relative movement (that is, no slippage) between contacting points on the drive roll 104 and diverter idling roll 106, in the situation where media is interposed between those elements. That lack of relative movement ensures that the media will not be subjected to marking during the transport process. With those design requirements, those of skill in the art will be able to design specific embodiments to meet particular functional requirements.

The media guiding system 100 may include a control mechanism, not shown in FIG. 1, to set the indentation level of the release roll 114 into the drive roll 104. The control mechanism can employ any of the conventional means to those in the art to set the release roll 114 indentation level. In one embodiment, the control mechanism includes sliding bearings along slots or guides to support the release roll 114, controlling distance between the release roll 114 and the drive roll 104. Alternatively, a stepper motor may rotate a shaft with cams, engaging support bearings. The stepper motor may rotate such that the cams engage the support bearings more, pressing the release roll 114 into the drive roll 104 depending on the desired indentation level. Another embodiment provides a non-dynamic arrangement that sets the indentation level manually, employing support bearings located with setscrews.

Those skilled in the art will be able to select a conventional control mechanism, such as a computer-controlled mechanism, an electromechanical mechanism, or any other suitable mechanism known in the art, for the media guiding system 100.

The indentation level of the release roll 114 depends on the degree of curl required in media exiting the media guiding system 100. For example, if the release roll 114 does not penetrate into the drive roll 104, the media exhibits an up-curl upon leaving the device. Increasing the amount of penetration reduces the amount of up-curl, until the point is reached where media emerges with a completely compensated, flat profile. Further penetration produces a down-curl.

Thus, a particular imaging device that typically handles the same sort of media may be set to a single indentation configuration (no indentation, deep indentation, or medium indentation), designed to counteract problems on that media only. Imaging devices that encounter frequent media type changes can be provided with means for effecting configuration changes either manually or based on preset conditions. Those of skill in the art will be capable of implementing such adjustment devices as required.

FIG. 2 illustrates a flowchart describing an exemplary method 200 for diverting media from an input media path to an output media path in a media guiding system. FIG. 2 describes the method 200 implemented by the media guiding system 100.

At step 202, the input nip 108 receives media from the input media path 102. Media enters the media guiding system 100 from the input media path 102 to the input nip 108, at 4 point where the diverter idling belt 106 makes contact with the drive roll 104. Media received at the step 202 is clamped to the drive roll 104 by the diverter idling belt 106 at step 204. The adjustable idler rolls 110 and 112 facilitate this clamping operation.

Then, at step 206, the media is released after travelling the desired angular distance around the drive roll 104. As noted above, alternative embodiments allow the output nip 118 to be adjusted among various points on the surface of drive roll 104. Any such adjustment should be completed before commencing a given operation of the imaging device, of course. As media travels around the drive roll 104, the fact that the media is being wrapped around the drive roll 104 in inherently tends to induce curl, but the relatively large diameter of the turning radius minimizes that tendency. Additionally, curl tendency will vary considerably with the media being processed. As noted in the art, a turning radius that will definitely impart curl to heavyweight media may not affect lightweight media at all. Marking is also minimized because the design of the drive roll 104 and the diverter idling belt 106 eliminates relative motion between media and media path surfaces. Further, the diverter idling belt 106, distributes pressure over the entire contact surface, reducing pressure at any given point, which tends to minimize marking.

Step 208 ejects the released media to the output media path 116. The media travels around the periphery of drive roll 104 to the output nip 118, at which point it exits to the output media path 116.

As noted above, the amount of reverse curl imparted in the media depends on the indentation level of the release roll 114. For example, zero indentation of the release roll 114 into the drive roll 104 may result in a up-curled media, While increased indentation induces increased back curl, until that point is reached at which media exits the drive roll 104 with no curl whatsoever.

As can be appreciated, the disclosed method 200 does not require any particular sort of image forming apparatus. Both the system and the method of this disclosure can be implemented in a wide range of image-forming apparatus.

It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Those skilled in the art may subsequently make various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements without departing from the scope of the invention, which is defined solely by the claims appended hereto.

Claims

1. Apparatus for diverting media from an input media path to an output media path in an imaging system, comprising:

a drive roll; and

an idling belt carried on one or more idler rolls and a release roll, such that the idler belt is in contact with the drive roll between: an input nip, located for accepting media from the input media path; and an output nip, including the release roll, located for outputting media to the output media path.

2. The system of claim 1, wherein the drive roll surface is formed of a resilient material.

3. The system of claim 1, wherein the idling belt is configured to be driven solely by interaction with the drive roll, there being no relative motion between contacting points on the drive roll and the idling belt.

4. The system of claim 1, wherein the release roll is formed of a material harder than the material of the drive roll.

5. The system of claim 1, wherein the release roll penetrates into the drive roll to a predetermined depth.

6. The system of claim 5, wherein the penetration of the release roll into the drive roll is adjustable.

7. The system of claim 6, wherein the penetration of the release roll into the drive roll decurls the media.

8. The system of claim 1, wherein the diameter of the release roll is smaller than the diameter of the drive roll.

9. The system of claim 1, wherein the release roll is formed of steel.

10. Apparatus for diverting media from an input media path to an output media path in an imaging system, comprising:

a drive roll having a surface formed of a resilient material; and

an idling belt carried on one or more idler rolls and a release roll, the idling belt being configured to be driven solely by interaction with the drive roll, there being no relative motion between contacting points on the drive roll and the idling belt, and the idling belt being in contact with the drive roll between: an input nip, located for accepting media from the input media path; and an output nip, including the release roll, located for outputting media to the output media path; wherein the release roll is formed of a material harder than the material of the drive roll, and is adjustably positioned to penetrate into the drive roll to a predetermined depth.

11. The system of claim 10, wherein the penetration of the release roll into the drive roll decurls the media.

12. The system of claim 10, wherein the diameter of the release roll is smaller than the diameter of the drive roll.

13. The system of claim 10, wherein the release roll is formed of steel.

14. A method for diverting media from an input media path to an output media path in an imaging system, the method comprising:

receiving media from the input media path;

holding the media against a drive roll employing an idling belt, wherein the idling belt is carried on one or more idler rolls and there being no relative motion between contacting points on the drive roll and the idling belt,

conveying the media a predetermined angular distance around the drive roll to an output nip defined by the drive roll and a release roll, the release roll being positioned to penetrate into the drive roll to a predetermined depth; and

releasing the media to the output media path.

15. The method of claim 14, wherein the predetermined angular distance depends on the position of the release roll.

16. The method of claim 14, further comprising adjusting the penetration of the release roll into the drive roll.

17. The method of claim 16, wherein the adjusted penetration of the release roll decurls the media.