US20080237976A1

US20080237976A1 - Media Sheet Ramp For An Image Forming Device

Info

Publication number: US20080237976A1
Application number: US11/691,517
Authority: US
Inventors: Niko Jay Murrell; Phill Douglas Cole
Original assignee: Lexmark International Inc
Current assignee: Lexmark International Inc
Priority date: 2007-03-27
Filing date: 2007-03-27
Publication date: 2008-10-02

Abstract

The present application is directed to embodiments of an input device and methods to introduce a media sheet into an image forming apparatus. The device may include a support surface sized to support the media sheet. A ramp may be positioned adjacent to the support surface to direct the media sheet from the support surface to a media path. In one embodiment, a pick mechanism is positioned to move the media sheet from the support surface and alone the ramp. An adjustment member may be operatively connected to the ramp to adjust an angle of the ramp relative to the support surface depending upon a stiffness of the media sheet.

Description

BACKGROUND

The present application is directed to a media path for moving media sheets within an image forming device and, more specifically, to an adjustable ramp in an input area to introduce media sheets into the media path.
New image forming devices, such as printers, copiers, facsimile machines, and the like, are trending towards smaller overall sizes. The smaller sizes have various advantages including the devices fit within a smaller workspace and a reduction in shipping and packaging costs. These advantages may also come at a price. The reduction in overall size makes it difficult to design a reliable, robust media feed system.
The media feed system includes an input section where media sheets are initially placed prior to being introduced into a media path. The input section may include a support section to support one or more media sheets, and a ramp positioned at one end of the support section. A pick mechanism is positioned to contact and move one media sheet at a time from the support section, along the ramp, and into the media path. The design of the input section is more difficult due to the reduction in the overall size of the image forming device. The reduction in size results in the pick mechanism being positioned in closer proximity to the ramp. This closeness may cause the beam strength of the media sheets to increase thus making it difficult to buckle the sheet as it moves along the ramp. If the angle of the ramp is too aggressive, torque supplied by a motor driving the pick mechanism increases to overcome the greater reaction force at the ramp.
Many image forming devices are designed to form images on a variety of different media sheets. Examples of the different varieties include but are not limited to paper, envelopes, labels, cardstock, and signage. Designing a media feed system to accommodate each of these different types of media sheets is difficult. Further, the mechanical properties of the various media sheets are also diverse. The different mechanical properties may include but are not limited to fiber content, material type, thickness, roughness, and alignment and orientation at the support section. Therefore, there is a need to improve feed reliability for a broad range of media sheets.

SUMMARY

The present application is directed to embodiments of an input device to introduce a media sheet into an image forming apparatus. The device may include a support surface sized to support the media sheet. A ramp may be positioned adjacent to the support surface to direct the media sheet from the support surface to a media path. In one embodiment, a pick mechanism is positioned to move the media sheet from the support surface and along the ramp. An adjustment member may be operatively connected to the ramp to adjust an angle of the ramp relative to the support surface depending upon a stiffness of the media sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 2 is a perspective view of an input tray with two input sections according to one embodiment.

FIG. 3 is a perspective view of an input tray with one input section according to one embodiment.

FIG. 4 is a schematic diagram of a pick mechanism and ramp according to one embodiment.

FIG. 5 is a schematic diagram of a pick mechanism and ramp according to one embodiment.

FIG. 6 is a schematic diagram of a ramp according to one embodiment.

FIG. 7 is a schematic diagram of a ramp according to one embodiment.

DETAILED DESCRIPTION

The various embodiments disclosed herein are directed to a ramp to introduce media sheets into a media path from an input source. The ramp is positioned at an angle relative to a support member to guide the media sheets into the media path. The angle of the ramp is adjusted depending upon the media sheet. The angle may provide for a consistent motor load on a pick mechanism positioned at the input source for each of the various media sheets.
FIG. 1 illustrates a representative image forming device, such as a printer, according to one embodiment of the present invention. The exemplary image forming device 50 comprises a main body 51 that includes a front side and a back side. A control panel 59 may be located on the front side of the body 51. Using the control panel 59, the user is able to enter commands and generally control the operation of the image-forming device 50. For example, the user may enter commands to switch modes (e.g., color mode, monochrome mode), view the number of images printed, take the device 50 on/off line to perform periodic maintenance, and the like.
The main body 51 further includes a cavity 52 sized to accommodate an input tray 40. The input tray 40 in this embodiment includes a first input section 20 and a multipurpose input section 30. The multiple input sections allow for storing or introducing multiple types and sizes of media sheets that may be picked and fed into a media path 52 as required. The input sections may also be sized to hold a large capacity of media sheets.
The first input section 20 includes a receptacle 21 with an associated pick mechanism 22. The pick mechanism 22 may be connected to the input tray 40, or may be connected to the main body 51. A pick command is sent to the pick mechanism 22 to advance a media sheet from the receptacle 21 along a ramp 11 and into the media path 53.
The multipurpose input section 30 may also be located in the input tray 40 to introduce media sheets introduced by a user from outside the body 51 of image forming device 50. The multipurpose input section 30 includes an associated pick mechanism 22 to feed medial sheets along a ramp 11 and into the media path 53. Media sheets may be introduced into the multipurpose input section 30 through a multipurpose door panel 32. In the embodiment shown in FIG. 1, the multipurpose door panel 32 is shown in a partially open position and pivots about point 33 in the direction generally indicated by arrows M. The multipurpose door panel 32 opens a sufficient amount to permit the insertion of a variety of media sheets, such as paper, labels, envelopes, forms, and transparencies for feeding by the pick mechanism 22. Panel 32 may also function to support the media prior to being picked by the pick mechanism 22. The input tray 40 may be removable as indicated by arrow P for refilling the receptacle 21, and located on a lower section of the device 50.
From the various input sections 20, 30, media sheets contact ramps 11 and are then deflected by guides 29 towards the main media path 53. One or more registration rollers 54 disposed along the media path 53 align the media sheets and precisely controls its further movement. A media transport belt 55 forms a section of the media path 53 for moving the media sheets past a plurality of image forming units 60. In a typical color electrophotographic printer such as exemplary device 50, three or four colors of toner—cyan, yellow, magenta, and optionally black—are applied successively to a media sheet to create a color image. Correspondingly, the embodiment of FIG. 1 depicts four image formation stations 60 arrayed along the media transport belt 55. The transport belt 55 carries the media sheets successively past the image formation stations 60. At each station 60, an optical device 61 forms a latent image onto an associated photoconductive member or PC drum (not specifically labeled). The latent image is then developed by applying toner to the PC drum. The toner is subsequently deposited on the media sheets as they are conveyed past the image formation station 60.
Once the media sheets move past the image forming stations 60, a fuser 56 thermally fuses the loose toner to the media sheets. The media sheets then pass through reversible exit rollers 57 to an output stack 92 formed on the exterior of the body 51. Alternatively, the exit rollers 57 may reverse motion after the trailing edge of the media sheets have passed the entrance to a duplex path 58, thus directing the media sheet through the duplex path 58 and again into main media path 53 to print duplex images on the opposite sides of the media sheets. It should be understood that while the foregoing description relates to a color electrophotographic printer as shown in FIG. 1, the present invention is not limited to color printers, but may be advantageously applied to other types of image forming devices 50, including but not limited to, single-color laser printers and inkjet printers.
FIG. 2 illustrates one embodiment of the input tray 40 that combines input sections 20, 30 into a common assembly, thus conserving vertical space in the image forming device 50. The first input section 20 includes a receptacle 21 with a bottom support surface 28 to contain a stack of media sheets. A first ramp 11 is positioned to guide the media sheets away from the receptacle 21. The second input section 30 includes a second support surface 28 to support the media sheets and a second pick mechanism 22 that guides the media sheets along a second ramp 11 and into the media path 53. The door 32 is in an open orientation and forms a section of the second support surface 28 to support the media sheets prior to being moved by the pick mechanism 22.
Another input tray 40 is illustrated in FIG. 3. Input tray 40 includes a single input section that includes a receptacle 21 with a support surface 28 to position a stack of media sheets. A ramp 11 is positioned at the end of the receptacle 21 to guide the media sheets from the receptacle 21.
The various pick mechanisms 22 move the media sheets into the media path 53. FIG. 4 illustrates a schematic diagram of one pick mechanism 22 positioned at the input tray 40. The pick mechanism 22 includes a pivoting arm 41 with one or more pick tires 42 at the end to contact a top-most media sheet on the support surface 28. The pick mechanism 22 further includes a series of gears 43 operatively connected to a motor 80. A controller 81 sends a pick command to the motor 80 causing the gears 43 and pick tire(s) 42 to rotate and engage the media stack on the support surface 22. The pick tire(s) 42 grips the top-most media sheet and push it against the ramp 11. The pick mechanism 22 operates under a no-slip condition with the motor 80 continuing to provide necessary torque until the media sheet is picked or a motor failure occurs. Once the media sheet is picked, the pick tire(s) 42 continue to move the media sheet along the ramp 11 and guide 29 until the leading edge of the media sheet reaches the registration rollers 54.
The angle of the ramp 11 affects the feed reliability of moving a media sheet into the media path 53. The ramp angle also affects the amount of motor torque necessary to move the media sheet from the receptacle and along the ramp 11. In general, a larger ramp angle provides for a lower motor torque than a steeper ramp angle. If the image forming device 50 were to form images on only a single type of media sheet, the ramp angle could be established to optimize feed reliability and motor torque. However, the image forming device 50 is able to form images on a variety of different types of media sheets, such as envelopes, cardstock, labels, paper, signage, and the like. These different types of media sheets may include different mechanical properties that affect the feed reliability and motor torque. The various mechanical properties include but are not limited to fiber content, alignment, material type, thickness, orientation, and roughness. Therefore, the ramp 11 may be adjusted at various angles to accommodate various types of media sheets.
The ramp angle α is formed between the support surface 28 and the ramp 11. FIG. 4 illustrates one embodiment with the ramp 11 adjustable between a first ramp angle α1 and a second ramp angle α2. Normally, media sheets with a higher stiffness require a larger angle, such as α2. Conversely, more flexible media sheets can be accommodated with a steeper angle, such as α1. Various mechanisms may be used for adjusting the angle of the ramp 11.
FIG. 5 illustrates one embodiment for adjusting the angle of the ramp 11. The angle of the ramp 11 in this embodiment is controlled by a spring 12. The ramp 11 includes a pivoting first end 13 and a second end operatively connected to a slot 14. A biasing member 12 contacts a back side of the ramp 11 and biases the ramp 11 towards the support surface 28. In one embodiment, biasing member 12 is a leaf spring with a first end in contact with the back side of the ramp 11 and a second end held in position by a mount 15.
During a media sheet pick, the pick tire 42 rotates and forces the top-most media sheet from the media stack M against the ramp 11. If the media sheet includes a low stiffness, the ramp 11 remains in a first orientation. The media sheet will bend and the leading edge will move upward along the ramp 11 due to the driving force of the pick tire 42. The ramp 11 remains in the first orientation illustrated in solid lines in FIG. 5 because the low stiffness media sheet exerts a first force against the ramp 11 that is less than a force exerted on the ramp 11 by the biasing member 12. In one embodiment, the first ramp orientation includes the ramp 11 in contact against a first end 14 a of the slot 14. This first orientation may position the ramp 11 against the support surface 28, or may be spaced away from the support surface 28.
If the media sheet includes a higher stiffness, the force exerted on the ramp 11 is greater than the force of the biasing member 12. This increased force causes the ramp 11 to pivot about the first end 13 with the second end sliding along the slot 14. This pivoting movement increases the angle of the ramp 11 as illustrated in the dashed lines of FIG. 5. This increased angle facilitates bending of the media sheet and movement of the leading edge upward along the ramp 11. In one embodiment, the force exerted by the media sheet causes the ramp 11 to slide to a second orientation that is in contact with a second end 14 b of the slot 14. The second orientation may position the ramp 11 in contact with or spaced away from the guide 29. After the media sheet moves along the ramp 11, the force of the biasing member 12 may return the ramp 11 to the first orientation.
In one embodiment, the ramp 11 is in contact with the first end 14 a of the slot 14 in the first orientation, and in contact with the second end 14 b in the second orientation. However, the ramp 11 may be positioned at various angles between the first and second ends 14 a, 14 b depending upon the type of media sheets, and the force of the spring 12.
FIG. 6 illustrates another embodiment with a biasing member 12 positioning the ramp 11. Biasing member 12 is compressed depending upon the type of media sheet being fed by the pick mechanism 22. Compression of the biasing member 12 causes the ramp 11 to pivot about the end 13 and adjust the ramp angle accordingly. A stop member 16 may be positioned to set the maximum extent of movement of the ramp 11. Various types of compressible biasing members 12 may be used including a coil spring and a foam member. In another embodiment, a torsion spring is positioned to adjust the angle of the ramp 11.
In one embodiment with the ramp 11 being positioned by a biasing member 12, the biasing member 12 is compressed to some extent during movement of each media sheet. The compression causes the angle of the ramp 11 to change accordingly. In another embodiment, the biasing member 12 may not be moved during movement of certain types of media sheets. The angle of the ramp 11 does not change until a media sheet is moved with physical properties that cause a force that exceeds the force of the biasing member 12. In one specific embodiment, the biasing member 12 includes a spring rate to ensure media sheets stiffer than 32# will move the ramp 11 from the first orientation.
Another adjustment method requires the user to manually position the ramp 11 to the desired angle. The ramp 11 is accessible to the user when the input tray 40 is removed from the main body 51 of the image forming device 50. Using FIG. 3 as an example, the input tray 40 may include one or more locking mechanisms 26 to set the position of the ramp 11. In one embodiment, locking mechanisms 26 are positioned on one or both sidewalls 27 to engage with the ramp 11. Locking mechanisms 26 may include a variety of different mechanisms, including but not limited to a ball and detent combination, a fastener such as a screw or pin, and a retcheting mechanism with a dial.
In use, the user determines the type of media sheets that will be inserted into the input tray 40. The user than adjusts the ramp 11 to the appropriate angle to facilitate movement of the media sheets. In one embodiment, the user may enter the type of media sheet into the control panel 59. The controller 81 receives the input and displays the appropriate ramp angle that is then set by the user. In another embodiment, indicia is located on the input tray 40 or other convenient location that instructs the user of the appropriate ramp angle.
Another adjustment method features the controller 81 adjusting the angle of the ramp 11. FIG. 7 schematically illustrates an adjustment mechanism 37 operatively connected to the ramp 11. Adjustment mechanism 37 is selectively positionable between a variety of heights to adjust the angle of the ramp 11. In one embodiment, adjustment mechanism 37 includes a pair of telescoping members with a gear 38 mounted to one of the members and engaged with teeth on a second member. Rotation of the gear 38 in a first direction causes an increase in the overall length of members, and rotation in a second direction causes a decrease. A motor 85 is operatively connected to drive the gear 38 in the first and second directions.
In use, a user places one or more media sheets on support surface 28. The user then inputs the type of media through the control panel 59. The input is received from the controller 81 which in turn determines the necessary angle for the ramp 11. Controller 81 operates motor 85 which in turn rotates the gear 38 to adjust the length of the mechanism 37 and hence the angle of the ramp 11. The position of the ramp 11 may be determined by an encoder within the motor 85, or a sensor located proximate to the ramp 11.
Various other embodiments of adjustment mechanisms 37 may be used to adjust the angle of the ramp 11. Additional embodiments include a solenoid, rack-and-pinion arrangement, and various other linear or rotational actuators.
The controller 81 described above may be implemented as a single microcontroller or microprocessor that includes logic circuitry to implement the functions described above. The functions implemented by the controller may be embodied in hardware (including an application specific integrated circuit (ASIC), field programmable gate array (FPGA), etc.) and/or software (including firmware, software, micro-code, etc.). Further, it will be appreciated that the controller 81 may be a separate device as shown in FIGS. 4 and 7, or it may be part of the overall device controller or processor (not shown).
The adjustable ramp 11 of these embodiments provides various advantages. The motor loads to the pick mechanism motor 80 are reduced and peak loads are more predictable. This may provide for smaller motors and/or may allow for imaging a broader range of media sheets. Further, a more consistent pick profile is maintained across the variety of different media sheets. Overall feed reliability is improved with motor stalls, timing errors, and other related media jams being reduced.
In one embodiment as illustrated in FIGS. 1 and 4, an inlet 64 is positioned within the input tray 40 to receive media sheets from additional storage locations (not illustrated). The inlet 64 leads from the storage locations to the media path 53. The one or more ramps 11 may be positioned to prevent blocking media sheets moving along the inlet 64. In one embodiment, the ramps 11 remain away from the inlet 64 in the various orientations. In one embodiment, the ramps 11 are away from the inlet 64 in the first orientation, and extend across the inlet 64 in a second orientation.
FIG. 1 illustrates on embodiment of an image forming device 50 featuring a direct transfer system where the toner images from the imaging units 60 are transferred directly to the media sheets. In another embodiment, the device 50 includes a secondary transfer system. The toner images are initially transferred from the imaging units 60 to an intermediate member, and then transferred a second time to the media sheets.
In one embodiment as illustrated in FIGS. 5 and 6, the ramp 11 includes a first pivoting end 13 that is positioned on a first side of a line that is formed by the support surface 28. The ramp 11 also includes a second end that is positioned on a second side of the line formed by the support surface 28.
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. In one embodiment, the support surface 28 is positioned at an angle to the ramp 11 such the media sheets remain in contact with the ramp 11 prior to being picked. In another embodiment, the input sections include a biasing mechanism that contacts the media sheets and forces the leading edges against the ramp 11 prior to be picked. 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. An input device to introduce a media sheet into an image forming apparatus, the device comprising:

a support surface sized to support the media sheet;

a ramp positioned adjacent to the support surface to direct the media sheet from the support surface to a media path;

a pick mechanism positioned to move the media sheet from the support surface and along the ramp; and

an adjustment member operatively connected to the ramp to adjust an angle of the ramp relative to the support surface depending upon a stiffness of the media sheet.

2. The device of claim 1, wherein the ramp is positioned at an end of the support surface.

3. The device of claim 1, wherein the ramp includes a first pivoting end that is positioned on a first side of a line formed by the support surface and a second end positioned on a second side of the line.

4. The device of claim 1, wherein the adjustment member is a biasing member that contacts a first side of the adjustment member opposite from a second side that is contacted by the media sheet.

5. The device of claim 1, wherein the pick mechanism moves the media sheet against the ramp and exerts a force on the ramp that moves the ramp from a first orientation with a first ramp angle to a second orientation with a second ramp angle that is greater than the first ramp angle.

6. The device of claim 1, wherein the ramp includes a first pivoting end and a second end operatively positioned within a slot, the ramp being movable between a first orientation with the first end in contact with a first side of the slot and a second orientation with the first end in contact with a second side of the slot.

7. An input device to introduce a media sheet into an image forming apparatus, the device comprising:

a support surface sized to support the media sheet;

a ramp pivotally positioned at an end of the support surface to direct the media sheet from the support surface to a media path; and

an adjustment member operatively connected to the ramp to adjust an angle of the ramp relative to the support surface depending upon a stiffness of the media sheet;

the ramp being pivotable between a first orientation forming a first angle with the ramp in proximity to the support surface, and a second orientation forming a larger second angle with the ramp positioned away from the support surface.

8. The device of claim 7, wherein the ramp is in contact with the support surface in the first orientation.

9. The device of claim 7, further including a pivot member positioned at a first end of the ramp with a second section of the ramp that is spaced away from the first end being operatively positioned within a slot.

10. The device of claim 7, wherein the adjustment member is a biasing member positioned to contact a back side of the ramp opposite from the support surface.

11. The device of claim 7, further comprising a pick mechanism positioned to move the media sheet from the support surface and along the ramp, the pick mechanism include a pick tire that contacts the media sheet and a pivoting arm.

12. The device of claim 11, wherein rotation of the pick tire causes the media sheet to exert a force on the ramp to move the ramp from the first orientation to the second orientation.

13. A method of introducing a media sheet into an image forming apparatus comprising:

moving the media sheet from a support surface and against a ramp positioned at an end of the support surface;

exerting a force on the ramp through the media sheet and pivoting the ramp from a first orientation with a first angle to a second orientation with a larger second angle;

moving the media sheet from the support surface and along the ramp; and

returning the ramp back to the first orientation after the media sheet passes beyond the ramp.

14. The method of claim 13, wherein moving the ramp from the first orientation to the second orientation comprises bending a biasing member that is in contact with the ramp.

15. The method of claim 13, wherein moving the ramp from the first orientation to the second orientation comprises pivoting the ramp about a first end and sliding a second end of the ramp in a slot.

16. The method of claim 13, wherein the step of returning the ramp back to the first orientation after the media sheet passes beyond the ramp comprises contacting the ramp against the support surface.

17. The method of claim 13, further including moving a second media sheet with a greater stiffness than the media sheet from the support surface and exerting a second force on the ramp through the second media sheet and pivoting the ramp from the first orientation to a third orientation with a third angle, the third angle being larger then the first and second angles.

18. The method of claim 13, further including moving a second media sheet with a lesser stiffness than the media sheet from the support surface and exerting a second force on the ramp through the second media sheet and pivoting the ramp from the first orientation to a third orientation with a third angle, the third angle being larger than the first angle and less than the second angle.

19. The method of claim 13, further including returning the ramp back to the first orientation prior to moving a second media sheet from the support surface.

20. The method of claim 13, further comprising pivoting the ramp to the second orientation and contacting a back side of the ramp against a stop.