Patent Application
20080237976
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.
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.
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.
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
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
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
Another input tray 40 is illustrated in
The various pick mechanisms 22 move the media sheets into the media path 53.
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.
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
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
In one embodiment, the ramp 11 is in contact with the first end 14a of the slot 14 in the first orientation, and in contact with the second end 14b in the second orientation. However, the ramp 11 may be positioned at various angles between the first and second ends 14a, 14b depending upon the type of media sheets, and the force of the spring 12.
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
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.
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
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
In one embodiment as illustrated in
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.
