US20050017440A1

US20050017440A1 - Media registration mechanism for image forming device

Info

Publication number: US20050017440A1
Application number: US10/624,779
Authority: US
Inventors: Robert Jewell
Original assignee: Hewlett Packard Development Co LP
Current assignee: Hewlett Packard Development Co LP
Priority date: 2003-07-22
Filing date: 2003-07-22
Publication date: 2005-01-27

Abstract

A media registration mechanism for aligning print media comprising a registration wall and a plurality of media carriers configured parallel to each other and parallel to the registration wall. Each of the plurality of media carriers can be positioned a different distance from the registration wall and configured to move print media in a direction along the registration wall. Also, each of the plurality of media carriers can be configured to move the print media at a speed based on a position of a media carrier relative to the registration wall to cause the print media to rotate towards and align against the registration wall.

Description

BACKGROUND

In some image forming devices, media registration mechanisms have been incorporated into the media path in order to help align an edge of a sheet of print media (hereinafter referred to as “print media”). Aligning the print media helps to orient it in a consistent position for imaging or outputting.
In prior media registration mechanisms, moving belts were angled towards a registration fence to achieve media registration. When the print media came into contact with the angled belts, the print media was carried into and against the fence.
In other image forming devices, vacuum rotor technology has been used to orient the print media in a consistent position for imaging or outputting. Vacuum rotor technology uses vacuum suction cups to grab print media from one imaging station, swing the print media about an arc to the next imaging station, and then drop off the print media to the next imaging station.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings which are incorporated in and constitute a part of the specification, embodiments of a mechanism and method are illustrated which, together with the detailed description given below, serve to describe example embodiments of the mechanism and method. It will be appreciated that the illustrated boundaries of elements (e.g., boxes or groups of boxes) in the figures represent one example of the boundaries. One of ordinary skill in the art will appreciate that one element may be designed as multiple elements or that multiple elements may be designed as one element. An element shown as an internal component of another element may be implemented as an external component and vice versa.
Further, in the accompanying drawings and description that follow, like parts are indicated throughout the drawings and description with the same reference numerals, respectively. The figures are not drawn to scale and the proportions of certain parts have been exaggerated for convenience of illustration.
FIG. 1 is a diagram of one embodiment of an image forming device 100;
FIG. 2 is a top view of one embodiment of a media registration mechanism 200;
FIG. 3 is a top view of another embodiment of a media registration mechanism 300;
FIG. 4 illustrates one embodiment of a methodology for media registration;
FIG. 5 illustrates another embodiment of a methodology associated with moving print media along a media path in an image forming device; and
FIGS. 6A-6E illustrate one embodiment of an media registration sequence.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

Illustrated in FIG. 1 is one embodiment of an image forming device 100. The image forming device 100 may be a printing device such as a liquid electrophotographic printer, a laser printer, an inkjet printer, a copier, an all-in-one product, a multifunctional peripheral (MFP) device, or other type of imaging device that forms an image onto print media. In this embodiment, the image forming device 100 may include a media handling mechanism, such as a media feeder 105, configured to supply sheets of print media to a media registration mechanism 110 from an input position. The registration mechanism 110 is configured to align the print media prior to imaging. In one embodiment, the registration mechanism 110 is configured to substantially align an edge of the print media against a registration wall so that each sheet of print media is in a relatively consistent position and orientation for imaging. The registered print media is then advanced to an image forming mechanism 115 where an image is formed onto the print media. The image forming device 100 may include one or more media paths along which the print media is carried.
The image forming mechanism 115 may be embodied in a variety of different ways depending on the type of image forming device 100. For example, the image forming mechanism 115 may include a liquid electrophotographic mechanism, a laser imaging mechanism, an inkjet mechanism, a thermal printing mechanism, a digital image reproduction mechanism, or other type of printing mechanism. Once the print media is imaged by the image forming mechanism 115, the print media is moved along a path to an output 120. The output 120 may be one or more output trays or other devices from which a user can receive the imaged print media.
Illustrated in FIG. 2 is a top view of one embodiment of a media registration mechanism 200 or media steering mechanism. The media registration mechanism 200 includes a registration or alignment wall 205, or fence, that defines a reference axis A. The registration wall 205 is configured to assist in the process of positioning and orienting print media prior to imaging. For example, as print media is carried along a media path, represented by arrow B, an edge of the print media is substantially aligned against the registration wall 205 before the print media is fed to the image forming mechanism (not shown). In this manner, multiple sheets of print media can be substantially aligned in a consistent position and orientation. By aligning the print media, an image can be formed at a generally consistent location on the print media relative to the reference axis A.
With further reference to FIG. 2, in one embodiment, the media registration mechanism 200 can include multiple media carriers that carry print media along the media path B. In one embodiment, a first media carrier can be a first transport belt 210 and a second media carrier can be a second transport belt 215. It will be appreciated that other types of media carriers may be used instead of belts such as nipped rollers, vacuum assisted belt, or an electrostatically charged web. In one embodiment, both the first and second belts 210, 215 are positioned substantially parallel to each other and the registration wall 205. For example, the first belt 210 can be positioned between the second belt 215 and the registration wall 205 such that the first belt 210 is adjacent to the registration wall 205 while the second belt 215 is adjacent to the first belt 210. In other words, the second belt 215 is offset or spaced a greater distance away from the registration wall 205 than the first belt 210.
The first belt 210 can be configured to engage the print media and move or otherwise carry it in a linear direction along the media path B at a first speed or velocity. The second belt 215 is also configured to engage the print media and simultaneously move it in a linear direction along the media path B at a second speed. In one embodiment, the first speed of the first belt 210, represented by arrow C, is less than the second speed of the second belt 215, represented by arrow D (which is longer than arrow C to illustrate the difference in speeds). With the different speeds, upon concurrently engaging the print media, the first belt 210 moving at the first speed and the second belt 215 simultaneously moving at the second speed causes the print media to rotate towards the registration wall 205 until an edge or side of the print media is substantially aligned against the registration wall 205. In other words, because of the difference in relative speeds between the first and second belts 210, 215 (where the first belt 210 travels slower than the second belt 215), the print media is steered towards the registration wall 205. One example of an alignment process will be described with reference to FIGS. 6A-6E.
To drive the first and second belts 210, 215 at different speeds, the media registration mechanism 200 may further include drive means coupled to the first and second belts 210, 215. In one embodiment, the drive means can include a drive mechanism 220 comprising a motor 225 coupled to a drive shaft 230. The drive shaft 230 can include a first diameter portion 235 and a second diameter portion 240 that is larger than the first diameter portion 235. In one embodiment, the first and second diameter portions 235, 240 may comprise lobes that project radially from the drive shaft 230 to create the different diameter portions. Of course, the basic diameter of the drive shaft 230 can serve as the first diameter portion 235 and a lobe having a larger diameter than the basic diameter of the drive shaft 230 can serve as the second diameter portion 240. In another embodiment, the drive shaft 230 may be a single diameter shaft having pulleys or gears of different diameters disposed thereon to achieve the same or similar effect.
In another embodiment, the drive means may include two motors to independently drive the first and second belts 210, 215 at different speeds. It will be appreciated that other types of drive means may be used including any mechanical, electromechanical, electromagnetic components, or combinations thereof to drive the first and second belts 210, 215 at different speeds.
To transfer rotational movement of the drive shaft 230 to the first belt 210, the first belt 210 is drivingly engaged with the first diameter portion 235 of the drive shaft 230. Likewise, the second belt 215 is drivingly engaged with the second diameter portion 240 to transfer rotational movement of the drive shaft 230 to the second belt 215. In one embodiment, the linear speeds of the first and second belts 210, 215 can be the product of an angular speed of the drive shaft 230 multiplied by the radius of the first and second diameter portions 235, 240, respectively. Accordingly, when the drive shaft 230 is driven at one angular speed, the first and second belts 210, 215 are driven at different linear speeds since the first and second diameter portions 235, 240, respectively, of the drive shaft 230 have different radii. Thus, when the drive shaft 230 is rotated, the first belt 210 travels at the first speed and the second belt 215 travels at the second speed (which is greater than the first speed of the first belt 210). Of course, different relationships between the first and second speeds of the belts 210, 215 can be used.
As a sheet of print media comes into contact with the first and second belts 210, 215, the print media is carried along the media path B. However, the difference in speeds causes the print media to rotate and move towards the slower belt and, hence, towards the registration wall 205. For example, the print media will rotate until an edge or side of the print media substantially abuts against the registration wall 205 thereby causing the print media to substantially align against the registration wall 205. In other words, when the first belt 210 is traveling at a speed less than the second belt 215, the print media is steered towards the registration wall 205 until the edge of the print media is substantially aligned against the registration wall 205 and, continues to move along the media path B.
By configuring a plurality of belts such as the first and second belts 210, 215 to travel at different relative speeds, the print media can be caused to rotate towards the slower belt. The slower belt (e.g., the first belt 210) creates drag on a portion of the print media relative to a portion of the print media in contact with the faster belt (e.g., the second belt 215). A percentage difference between the speed of the first belt 210 and the second belt 215 can be proportional to a percentage difference between the first diameter portion 235 of the drive shaft 230 and the second diameter portion 240 of the drive shaft 230, respectively. For example, if the first diameter portion 235 is 5% less than the second diameter portion 240, then the speed of the first belt 210 would be 5% less than the speed of the second belt 215. In one embodiment, the first diameter portion 235 of the drive shaft 230 is between about 1% and about 5% less than the second diameter portion 240 of the drive shaft 230. Of course, other desired percentage ratios can be used.
To support the first and second belts 210, 215, the media registration mechanism 200 can include a first idler shaft 245 and a second idler shaft 250. In one embodiment, the first idler shaft 245 is positioned at one end of the first and second belts 210, 215 and the second idler shaft 250 is positioned at the other end of the first and second belts 210, 215. The drive shaft 230 can be positioned between the first and second idler shafts 245, 250. Of course, other configurations of the shafts 230, 245, 250 can be used as well as different numbers of shafts. In one embodiment, the first idler shaft 245 can include a first bearing 255 and a second bearing 260. The second idler shaft 250 can include a third bearing 265 and a fourth bearing 270. For example, the first belt 210 can be configured to be supported by the first bearing 255 and the third bearing 265, while the second belt 215 can be configured to be supported by the second bearing 260 and the fourth bearing 270.
Illustrated in FIG. 3 is a top view of another embodiment of a media registration mechanism 300. Media registration mechanism 300 is similar in structure to and operates in a similar manner as media registration mechanism 200 illustrated in FIG. 2. However, the media registration mechanism 300 includes a third media carrier such as a third belt 305. Of course, it will be appreciated that any number of media carriers can be configured to carry the print media as described above. In one embodiment, the third belt 305 can be spaced a greater distance away from the registration wall 205 than the second belt 215. Also, the third belt 305 can be positioned substantially parallel to the first and second belts 210 and the registration wall 205.
The third belt 305 can be configured to engage print media and simultaneously move it in a linear direction along the media path B at a third speed. In one embodiment, the third speed of the third belt 305, represented by arrow E (which is longer than arrows C and D to illustrate the difference in speeds), is greater than the second speed of the second belt 215. Hence, the speed of each belt increases as the distance between each belt and the registration wall 205 increases. In this embodiment, upon concurrently engaging the print media, the first belt 210 moving at the first speed, the second belt 215 simultaneously moving at the second speed, and the third belt 305 simultaneously moving at the third speed causes the print media to rotate towards the registration wall 205.
To drive the first, second, and third belts 210, 215, 305 at different relative speeds, the media registration mechanism 300 may further include drive means coupled to the first, second, and third belts 210, 215, 305, respectively. In one embodiment, the drive means includes a drive mechanism 310 that is similar in structure to, and operates in a similar manner as, the drive mechanism 220 illustrated in FIG. 2. However, the drive shaft 230 of the drive mechanism 310 includes a third diameter portion 315. The third diameter portion 315 of the drive shaft 230 is greater than the second diameter portion 240. In another embodiment, the drive means may include separate motors to independently drive each belt at a different speed. It will be appreciated that other types of drive means may be used including any mechanical, electromechanical, electromagnetic components, or combinations thereof to drive the first, second, and third belts 210, 215, 305 at different speeds.
To transfer rotational movement of the drive shaft 230 to the third belt 305, the third diameter portion 315 of the drive shaft 230 is drivingly engaged with the third belt 305. Because of the difference in diameters between the first, second, and third diameter portions 235, 240, 315, respectively, of the drive shaft 230, the drive shaft 230 can be driven at a single angular velocity, while the first, second, and third belts 210, 215, 305 travel at different linear velocities. Thus, when the drive shaft 230 is rotated, the third belt 305 travels at the third speed, which is greater than the second speed of the second belt 215. As a sheet of print media comes into contact with the first, second, and third belts 210, 215, 305, the difference in speeds causes the print media to rotate and move towards the registration wall 205 until the edge or side of the print media substantially abuts against the registration wall 205 thereby causing the print media to substantially align against the registration wall 205.
With further reference to FIG. 3, the media registration mechanism 300 can further include a fifth bearing 320 disposed on the first idler shaft 245 and a sixth bearing 325 disposed on the second idler shaft 250 to support the third belt 305. Of course, any number of bearings can be used.
Illustrated in FIG. 4 is one embodiment of a methodology 400 associated with registering print media within an image forming device. The illustrated elements denote “processing blocks” and represent functions and/or actions taken for registering print media. In one embodiment, the processing blocks may represent software instructions or groups of instructions that cause a computer or processor to perform an action(s) and/or to make decisions that control another device or machine to perform the processing. It will be appreciated the methodology may involve dynamic and flexible processes such that the illustrated blocks can be performed in other sequences different than the one shown and/or blocks may be combined or, separated into multiple components. The foregoing applies to all methodologies described herein.
With reference to FIG. 4, the methodology 400 includes moving print media along a media path along a registration wall (block 405). Portions of a sheet of print media are then moved along the media path by multiple belts configured to be driven at different speeds relative to the registration wall (block 410). For example, portions of the print media that are closer to the registration wall are moved at slower speeds than portions farther away from the registration wall. For example, if using multiple belts to carry the print media, a belt positioned closer to the registration wall would be configured to be driven at a slower speed than a belt positioned farther away from the registration wall. In other words, the speed of each belt increases as the belt is further spaced from the registration wall.
One effect of simultaneously driving multiple belts at different speeds relative to the registration wall is that the print media will rotate towards the registration wall while still moving along the media path. This causes the print media to be steered towards the registration wall until an edge of the print media is substantially aligned against the registration wall while simultaneously moving the print media along a linear media path (block 415). Optionally, the print media may be advanced to an image forming mechanism after the print media has been registered.
Illustrated in FIG. 5 is another embodiment of a methodology associated with moving print media along a media path in an image forming device. With reference to FIG. 5, one process 500 involves moving print media along a media path in an image forming device that includes an alignment wall positioned along a portion of the media path and is substantially parallel to the media path. The process 500 includes moving a first portion of the print media along the media path at a first speed (block 505). Simultaneously, a second portion of the print media is moved along the media path at a second speed that is different from the first speed (block 510). An effect of simultaneously moving the first and second portions of the print media at different speeds is that the print media will rotate towards the alignment wall, while still moving the print media along the media path. The rotation of the print media causes a side edge of the print media to substantially align against the alignment wall. In another embodiment, the process 500 may include simultaneously moving at least a third portion of the print media along the media path at a third speed different from the first and second speeds.
Illustrated in FIGS. 6A-6E is one embodiment of a media registration sequence using, for example, the media registration mechanism 300 described above and illustrated in FIG. 3. As previously mentioned, the media registration mechanism 300 includes the registration wall 205 and the first, second, and third belts 210, 215, 305 (hereinafter collectively referred to as “the belts”) configured to travel at different speeds. For example, the third belt 305 is traveling at a speed greater than the second belt 215, which is traveling at a speed greater than the first belt 210. As shown in FIG. 6A, a sheet of print media 605, having a leading edge 610, a side edge 615, and a trailing edge 620, is carried along a media path B. In one embodiment, the print media 605 is oriented such that the leading edge 610 of the print media 605 is substantially perpendicular to the registration wall 205 and the side edge 615 is substantially parallel to the registration wall 205, but may be spaced a distance away from the registration wall 205.
As shown in FIG. 6B, once the print media 605 comes into contact with the belts, the belts engage different portions of the print media 605 and simultaneously move the different portions of the print media 605 at different speeds along the media path B. The speeds of the belts decrease for a belt positioned closer to the registration wall 205. One effect of simultaneously moving the different portions of the print media 605 at different speeds causes the print media 605 to rotate towards the registration wall 205, in the direction represented by arrow F, while still moving along the media path B.
As shown in FIG. 6C, the print media 605 continues to rotate until one corner 625 of the print media 605 (i.e., meeting of the leading edge 610 and the side edge 615 of the print media 605) comes into contact with the registration wall 205. As shown in FIG. 6D, once the corner 625 of the print media 605 comes into contact with the registration wall 205, the belts continue to move and try to rotate the print media 605 thereby creating additional friction between the belts and the print media 605. The friction between the belts and the print media 605 creates a moment, represented by arrow G, that is induced about the point of contact with the registration wall 205. The moment causes the trailing edge 620 of the print media 605 to rotate towards the registration wall 205. As shown in FIG. 6E, the print media rotates towards the registration wall 205 until the side edge 615 of the print media 605 is in contact with and is substantially aligned against the registration wall 205. Additional sheets of print media would also be similarly aligned against the registration wall 205.
While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention, in its broader aspects, is not limited to the specific details, the representative apparatus, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's general inventive concept.

Claims

1. A media registration mechanism for aligning print media in an image forming device, the mechanism comprising:

a registration wall;

a plurality of media carriers configured parallel to each other and parallel to the registration wall, each of the plurality of media carriers being positioned a different distance from the registration wall and configured to move print media in a direction along the registration wall; and

each of the plurality of media carriers being configured to move the print media at a speed based on a position of a media carrier relative to the registration wall to cause the print media to rotate towards and align against the registration wall.

2. The media registration mechanism of claim 1 wherein the plurality of media carriers include a plurality of belts.

3. The media registration mechanism of claim 1 wherein a media carrier positioned closer to the registration wall is configured to move the print media at a slower speed than another media carrier positioned farther away from the registration wall.

4. The media registration mechanism of claim 1 wherein the plurality of media carriers includes at least a first belt and a second belt, the first belt being positioned between the second belt and the registration wall.

5. The media registration mechanism of claim 1 further comprising a drive means coupled to the plurality of media carriers for driving the plurality of media carriers at different speeds.

6. The media registration mechanism of claim 5 wherein the drive means comprises a motor coupled to a drive shaft including a first pulley having a first diameter and a second pulley having a second diameter that is greater than the first diameter wherein the first belt is in driving engagement with the first pulley and the second belt is in driving engagement with the second pulley.

7. The media registration mechanism of claim 6 further comprising:

a first idler shaft and a second idler shaft wherein the drive shaft is positioned between the first idler shaft and the second idler shaft,

the first and second idler shafts each include a first bearing and a second bearing wherein the first belt is in driving engagement with each of the first bearings of the first and second idler shafts and the second belt is in driving engagement with each of the second bearings of the first and second idler shafts.

8. The media registration mechanism of claim 7 wherein the first diameter of the first pulley is between about 1% and about 5% less than the second diameter of the second pulley such that the second speed of the second belt is between about 1% and about 5% less than the first speed of the first belt.

9. The media registration mechanism of claim 1 further comprising a plurality of motors each coupled to a media carrier for driving each media carrier at different speeds.

10. A media steering mechanism for positioning a sheet of media prior to imaging, the mechanism comprising:

a fence;

a plurality of media carriers, each of the media carriers configured to move the sheet of media in a direction substantially parallel to the fence, each of the media carriers being offset a different distance from the fence in one direction; and

a drive mechanism for driving each of the media carriers at a speed less than an adjacent media carrier that is positioned a greater distance away from the fence such that the sheet of media is steered towards the fence to cause an edge of the sheet of media to contact the fence.

11. The media steering mechanism of claim 10 wherein the drive mechanism comprises a motor and a drive shaft coupled to the motor, the drive shaft including different diameter portions configured to drive the plurality of media carriers at different speeds.

12. An image forming device comprising:

a media registration mechanism including:

a wall,

a first media carrier oriented substantially parallel to and spaced a first distance apart from the wall,

at least a second media carrier oriented substantially parallel to and spaced a second distance apart from the wall,

the first and second media carriers being configured to steer a sheet of media towards the wall when the first and second media carriers are driven at different speeds; and

an image forming mechanism configured to form an image onto the sheet of media once received from the media registration mechanism.

13. The image forming device of claim 12 wherein the media registration mechanism further comprises a drive mechanism coupled to the first and second media carriers for driving the first media carrier at a first speed and the second media carrier at a second speed greater than the first speed of the first media carrier.

14. The image forming device of claim 13 wherein the drive mechanism comprises a motor coupled to a drive shaft, the drive shaft including a first diameter portion and a second diameter portion that is larger than the first diameter portion wherein the first media carrier is in driving engagement with the first diameter portion and the second media carrier is in driving engagement with the second diameter portion.

15. The image forming device of claim 12 wherein the media registration mechanism further comprises a first motor coupled to the first media carrier for driving the first media carrier at a first speed and a second motor coupled to the second media carrier for driving the second media carrier at a second speed greater than the first speed of the first media carrier.

16. The image forming device of claim 12 wherein the image forming mechanism includes a liquid electrophotographic mechanism.

17. A method of aligning print media against a registration wall in an image forming device, the method comprising the steps of:

moving the print media along a media path substantially parallel to the registration wall;

simultaneously moving different portions of the print media at different speeds where a portion closer to the registration wall is moved at a slower speed to cause the print media to rotate towards the registration wall until an edge of the print media is substantially aligned against the registration wall.

18. The method of claim 17 further including the step of advancing the print media to an image forming mechanism once the print media has been aligned.

19. An image forming device having a media registration mechanism for aligning print media along a registration wall, the mechanism comprising:

a first media carrier configured to move print media in a direction substantially parallel to the registration wall;

a second media carrier, positioned adjacent to the first media carrier, configured to move the print media in the direction substantially parallel to the registration wall; and

the first and second media carriers configured to cause the print media to move towards the registration wall upon concurrently engaging the print media, until a side of the print media contacts and aligns along the registration wall.

20. The image forming device of claim 19 wherein the first media carrier is configured to move the print media at a first speed and the second media carrier is configured to move the print media at a second speed different from the first speed.

21. The image forming device of claim 20 wherein the first media carrier is positioned between the second media carrier and the registration wall and wherein the first speed is less than the second speed.

22. The image forming device of claim 19 wherein the first media carrier, the second media carrier and the registration wall are substantially parallel to each other.

23. The image forming device of claim 19 wherein the first media carrier is positioned between the second media carrier and the registration wall and being configured to cause a drag in the movement of the print media relative to the second media carrier.

24. The image forming device of claim 19 wherein the first and second media carriers include at least one belt for moving the print media in a linear direction.

25. The image forming device of claim 19 further including a drive means for moving the first media carrier at a first speed and for moving the second media carrier at a second speed different than the first speed.

26. The image forming device of claim 19 further including at least a third media carrier adjacent to the first and second media carriers.

27. A method of moving print media along a media path in an image forming device including an alignment wall positioned along a portion of the media path and being substantially parallel to the media path, the method comprising the steps of:

moving a first portion of the print media along the media path at a first speed; and

simultaneously moving a second portion of the print media along the media path at a second speed different from the first speed causing a side edge of the print media to align against the alignment wall.

28. The method of claim 27 further including simultaneously moving at least a third portion of the print media along the media path at a third speed different from the first and second speeds.

29. The method of claim 27 wherein the print media is rotated towards the alignment wall while moving along the media path.