Sensor and diverter mechanism for an image forming apparatus

An arm that directs media sheets along multiple paper paths of an image forming device. The arm is mounted to pivot when contacted by the media sheet to direct the sheets along the proper media paths, and divert the sheets from entering the improper media paths. A sensor positioned adjacent to the arm senses movement of the arm to determine the location and timing of the media sheets as they move along the paper paths. Sensor is operatively connected to a controller which tracks the movement of the media sheets through the image forming apparatus. The arm may further be positioned to determine the orientation of an internal part. The arm moves between first and second orientations depending upon the position of the internal part. The position of the arm is again determined by the sensor. The invention further includes methods of moving the position of the arm to determine the location of the media sheets and/or the orientation of the internal part.

BACKGROUND

Image forming devices place an image on a media sheet thus producing an imaged output. The image forming devices include a paper path for moving the media sheet and receiving the image. The paper path may include a first path for forming an image on a first side of the media sheet, and a second path for forming an image on a second side of the media sheet.

The image forming device also include doors which open and close to allow access to the paper path. The doors allow for paper jams to be accessed and removed without disassembling the image forming device.

Previous image forming devices have used multiple devices for sensing and directing the media sheets. In one prior device, a first sensor was used to sense a media sheet moving into a first predetermined area of the paper path. A second sensor indicated the media sheet entering into a second predetermined area of the paper path. Further, a diverter was positioned to direct sheets between the first path and second path depending upon whether imaging occurred on both sides of the media sheet. Additionally, another sensor indicated whether the access door was in an open or closed orientation. Thus, four separate sensing and directing devices were used within the image forming device.

Price is often a driving factor weighed by consumers when purchasing an image forming device. Often times, price is the primary requirement in the purchasing decision, with other machine parameters being of secondary importance. Therefore, design implementations with several different operations performed by a single element are advantageous. The multi-functional element is a less-expensive alternative. As always, quality of the formed images should not be degraded by the multi-functional element.

SUMMARY

The present invention is directed to an arm positioned along the media path to direct the media moving along the path. The arm is positioned along the media path such that arm members extend outward into the media path. A sensor is positioned relative to the arm to sense the movement of the arm. Signals from the sensor are forwarded to a controller that interprets the signals to determine the location of the media sheet.

The arm may further be positioned to determine the orientation of an access door. Image forming devices include an access door to access the paper path to remove media jams. The arm may be positioned such that the arm pivots to a predetermined position when the door is opened. The sensor detects the movement of the arm and signals the controller indicating the door is in the open orientation.

In one embodiment, the arm is positioned with a first member extending across the first media path. The arm pivots to a second position as the media sheet moves past the arm along the first media path. The arm then pivots back to the first position when the media sheet moves beyond the arm. The arm pivots to another position as a media sheet moves along the second media path. Again, the arm returns to the first position when the media sheet moves along the second media path beyond the arm. The arm also pivots when the access door is opened. The sensor detects the movement of the arm at each of these locations and signals to the controller.

DETAILED DESCRIPTION

The present invention is directed to an arm, generally illustrated as20, which directs media sheets through different paths within an image forming device100. The arm20is mounted to pivot when contacted by the media sheet, or when an access door380is opened or closed. A sensor70positioned adjacent to the arm20senses movement of the arm20to determine the location and timing of the media sheets, and/or the position of the access door380.

FIG. 1depicts an image forming device, indicated generally by100. The operation of the image forming device100is conventionally known. A single media sheet is “picked,” or selected, from a primary media stack300in a removable tray310by pick roller320. The media sheet is presented at registration rollers400, which align the sheet and precisely controls its further movement along the first paper path110. The media sheet passes the registration roller400and electrostatically adheres to transport belt420, which carries the media sheet successively past the four toner cartridges180,160,140, and120. At each toner cartridge180,160,140,120, a latent image is formed by printhead440onto the respective photoconductive (PC) drum in each toner cartridge. Toner is applied to the PC drum, which is subsequently deposited on the media sheet as it is conveyed past the toner cartridges180,160,140,120by the transport belt420. The toner is thermally fused to the media sheet by the fuser460. The media sheet is then moved through the arm20which directs the sheet to output rolls480. The media sheet is then either output from the device100into output tray500, or reversed and sent through a second, duplex path150for forming a toner image on a second side of the sheet.

FIG. 2illustrates the arm20that directs the media sheets along the first path110and second path150. Arm20includes a rod21having outwardly extending first member22, second member23, and third member24. Arm20is pivotally connected to the image forming device100such that the members22,23,24move between positions depending upon the position of a media sheet moving along the first and second paths110,150, and the orientation of the access door380. Arm20may have a variety of lengths to extend across a portion or the entirety of the paper paths110,150. In the embodiment ofFIG. 2, arm20includes a plurality of first members22extending outward along the length, a single second member23, and a single third member24. The present invention contemplates various numbers of first, second, and third members22,23,24extending outward from the rod21.

FIG. 3illustrates a cross-sectional view of the arm20. Arm20pivots about a point P that is positioned in the center of the rod21. In one embodiment illustrated inFIG. 4, arm20defaults to the first position when there are no other forces acting upon it, such as media sheet contact or the access door380being opened. In one embodiment, a biasing mechanism353extends between the arm20and image forming device100to bias the arm20towards the first position. In another embodiment, arm20defaults at the first position because a center of gravity G of the arm20is positioned along the first member22outward from point P. The position of the center of gravity G causes the arm20to rotate about point P such that the first member22blocks the first path110. In one embodiment, as illustrated inFIG. 3, a line A drawn through the pivot P and center of gravity G forms an angle β of about 79° with a line B defining the gravitational force. In both embodiments, the external forces that act upon the arm20are adequate to overcome the default forces and pivot the arm20from the first position.

A sensor70is positioned relative to the third member24to detect the movement of the arm20.

Various types of sensors30may be used to detect movement of the arm20. In one embodiment, a transmission sensor is used for detecting the characteristics. A transmission sensor transfers a signal from one location to another by means of light, radio, or infrared beams, or other like communication signals. In one embodiment, sensor70includes a transmitter71that transmits a light beam73that is received by receiver72. One type of light beam sensor is Model No. OJ6202XXX manufactured by Aleph International. Another embodiment features a proximity sensor that produces a signal when approached by an object. Sensors may use a variety of techniques to determine the characteristics including transmission sensing, reflectance sensing, capacitance sensing, inductance sensing, and magnetically-based sensing.

FIG. 4illustrates the arm20positioned at an intersection of the first path110and the second path150and downstream from the fuser460. The orientation of the arm20illustrated in solid lines indicates the first, default position. The arm position in dashed lines indicates the second position that is discussed in detail below.

As illustrated inFIG. 4, arm20assumes the first position when no forces are acting upon it with across the first path110. InFIG. 4, the arm20is in the first position as the leading edge of a media sheet90is exiting the fuser460. In the first orientation, the position of the third member24is detected by the sensor70. The controller95interprets the signal as indicating that the leading edge of the media sheet90has not yet reached the arm20.

FIG. 5illustrates the media sheet90contacting the arm20. The force of the media sheet90being driven by the fuser rolls460and/or output rolls480causes the arm20to pivot to the second position from the first position such that first member22does not block the first path110. The third member24moves away from the sensor70when the arm20is in the second position. The sensor70detects the movement and signals the controller95. Controller95interprets the signal as indicating the media sheet is currently passing the arm20. Arm20remains in the second position until the trailing edge of the media sheet90passes. Arm20then pivots to the first position due to the biasing mechanism or arm weighting. Upon passing the arm20, media sheet90is either driven by the output rolls480and exited from the image forming device100into the output tray500, or duplexed through the second path150.

FIG. 6illustrates the media sheet90at a time when the trailing edge has moved beyond the arm20. Arm20has returned to the first position after the trailing edge of the media sheet90passes the first member22. The movement of the arm20back to the first position is detected by the sensor70which signals the controller95.

The output rolls480reverse direction and feed the media sheet90into the second path150. The arm20is positioned with the first member22extending across the first path110blocking the media sheet90from being inadvertently driven back into the first path110. The media sheet90is blocked from re-entry by the plurality of first members22that extend along the length of the arm20.

FIG. 7illustrates the media sheet90contacting the second member23. The force of the driven media sheet90pivots the arm20to allow entry into the second path150. The sensor70is again tripped as the third member24pivots away from the sensor70thus registering a signal which is interpreted by the controller95as the media sheet90entering the second path150. Once the trailing edge of the media passes the second member23, arm20pivots back to the first position as illustrated in FIG.4. The movement of the arm20back to the first position is sensed by the sensor70and signals the controller95indicating that the media sheet90has entered the second path150and the trailing edge has passed the arm20.

In one embodiment, the arm20is positioned to sense the orientation of an access door380. Access door380is positioned on the image forming device100to access the fuser460. The access door380is pivotally connected to the image forming device100and positionable between open and closed orientations. In the open orientation, the access door380is pivoted to access the fuser460, and at least a portion of the first path110.FIG. 8illustrates the access door380in an open orientation.FIG. 9illustrates a partial side view illustrating the arm20in a third position when the access door380in an open orientation. Arm20pivots with the opening of the access door380and the third member24moves from the sensor70. This movement is detected and signaled to the controller95indicating the opening of the access door380. The arm20pivots back towards the first position upon closing the access door380. In one embodiment, access door380includes an opening390through which the second member23extends.

FIGS. 10 and 11illustrate one embodiment of a sensor70and the third member24. The sensor70features a transmitter71that emits a light beam that is received by receiver72. The third member24includes a paddle29having an opening28. The opening28is sized for the light beam to pass from the transmitter71to the receiver72, while the remainder of the paddle29blocks the passage of the light beam. In one embodiment, opening28is offset from a reference line of the paddle29. The sensor70and third member24may be arranged in a number of different manners. The sensor70may be blocked by the paddle29, or may not be blocked when the arm20is in the first position. Likewise, pivoting of the arm20may cause blocking or unblocking of the sensor70depending upon the specific arrangement. One embodiment of an arm having different characteristics in different sections of the arm is disclosed in U.S. patent application Ser. No. 10/639,297 entitled “Image Forming Device Having a Sensor with Two Separate Distinguishable Triggers” filed on the same day as the present application, assigned to Lexmark International, Inc., and incorporated herein by reference in its entirety.

There are a number of different manners of positioning the arm20to be detected by the sensor70. The controller95can be established to receive and interpret the signals to determine the movement of the media sheets90through the first and second path110,150, and the position of the access door380.

The opening28may further be used to determine movement of the arm20to the third position. In one embodiment, paddle29breaks the light beam with the arm20in the first position. When moving from the first position to the third position, arm20pivots such that the opening28moves between the sensor70. Therefore, the light beam is initially broken as the arm20is in the first position, not broken as the opening28passes through the sensor, broken when the remainder of the paddle passes through the sensor70, and again not broken after the paddle moves from the sensor70in the third position (see FIG.9). Controller95receives this string of signals from the sensor70and interprets it as the access door380being opened with the arm20moving from the first position to the third position.

In one embodiment, controller95includes a microprocessor, random access memory, read only memory, and in input/output interface. Controller95is operatively connected to media sensing and moving devices including the pick roll320, drive motors that drive the transfer belt420, one or more media sensor(s)318positioned along one or both paper paths110,150, fuser rolls460, and one or more nip rolls along the paths110,150. In one embodiment, at some designated time, controller95signals the pick rolls320to pick a media sheet90. The media sheet90moves through the beginning of the first path110and eventually trips a paper path sensor318. Controller95immediately begins tracking incrementally the position of the media sheet90by monitoring the feedback of media sensing and moving devices. Controller95can further determine the length of the media sheet90as it moves past the media sensors318. Embodiments of a similar system are disclosed in U.S. Pat. No. 6,330,424, and U.S. patent application Ser. No. 10/436,406 entitled “Pick Mechanism and Algorithm for an Image Forming Apparatus” filed May 12, 2003, both of which are assigned to Lexmark International, Inc., and herein incorporated by reference in their entirety.

Controller95is able to receive signals from the sensor70to track the position of the media sheet90, and determine and locate a position of a paper jam. The controller95tracks the position of the media sheet along the first path110. The controller95determines a paper jam if no signal is received from the sensor70within an expected time that the arm20has moved from the first position to the second position within an expected time. Likewise, controller95determines if the media sheet90clears the first path110by monitoring the arm20movement from the second position to the first position. Likewise, controller95monitors movement of the media sheet90into the second path150by monitoring the movement of the arm20.

Controller95further receives signals from the sensor70indicating the arm20has moved to the third position to indicate opening of the access door380. The controller95can determine the position of the media sheet90at the opening of the access door380.

The term “image forming device” and the like is used generally herein as a device to produce images on a media sheet90. Examples include but are not limited to a laser printer, ink-jet printer, fax machine, copier, and a multi-functional machine. One example of an image forming device is Model No. C750 available from Lexmark International, Inc. of Lexington, Ky.

The embodiment described includes a direct transfer from a series of photoconductive drums to the media sheet90. The present invention is also applicable for image forming devices100having secondary transfer of the toner image from an intermediate member to the media sheet. Further, the image forming device100may use any number of cartridges.

In the embodiments described above, sensor70is positioned to detect movement of the arm20by monitoring the movement of the third member24. The movement of the first member22, second member23, or rod21may also be sensed to determine the movement and position of the arm20. Additionally, more than one sensor70may be used for detecting movement and position of the arm20.

The orientation of the arm20and shape of the first member22may be such to facilitate movement of the media sheets90. In one embodiment, the arm20is orientated in the first position to form an obtuse angle between the first paper path110and the bottom surface22aof the first member that is contacted by the media sheet after leaving the fuser rolls460. The angle becomes larger as the arm20is pivoted to the second position to facilitate movement of the media sheet90. Likewise, as illustrated inFIG. 6, an angle formed between the media sheet and top surface of the second member23forms an obtuse angle to facilitate movement of the media sheet along the second path150. The arm20may also have other orientations depending upon the specific parameters.

In one embodiment, the position of the arm20at the first position is controlled by the first member22contacting an abutment (not illustrated) extending outward from the image forming device100. In another embodiment, the position is controlled because the second member23contacts the access door380thus limiting the extent of arm pivot.

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 arm20is not directly contacted by the media sheet90when being pivoted. The arm20is pivoted by other means based on the position of the media sheet90along the first and second media paths110,150. In one embodiment, arm20is positioned to detect the movement of an internal part of the image forming device. The example of the access door380is just one type of part that may be sensed. 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.