Image forming device having a sensor with two separate distinguishable triggers

The present invention is directed to a device having an arm and a sensor that can differentiate two events. The arm is pivotally mounted to move in different directions upon the occurrence of different events. A section of the arm includes a trigger section having an unequal distribution of a sensed characteristic. A first event moves the arm in a first direction that is sensed by the sensor in a first manner. A second event moves the arm in a second direction that is sensed by the sensor in a second manner. The sensor signals a controller that oversees the image forming process. Methods of operating the arm and sensor are disclosed for detecting the two separate events, and signaling the controller accordingly.

BACKGROUND

Image forming devices place an image on a media sheet thus producing an imaged output. The image forming device includes a media path for moving the media sheet and receiving the toner image. The media path may include a first path for forming a toner 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 media path. The doors allow for media jams to be accessed and removed without disassembling the image forming device.

Previous image forming devices use 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 media path. A second sensor indicated the media sheet entering into a second predetermined area of the media 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 a device that can distinguish between two separate events that are occurring to the image forming device. A first event causes the device to move in a first manner that is sensed in a first way. A second event causes the device to move in a second manner that is sensed in a second way. Therefore, a single device is able to differentiate between two separate events that occur to the image forming device.

In one embodiment, the device includes an arm and a sensor. The arm is pivotally mounted within the image forming device and includes a first end and a second end. A first section is positioned to be contacted upon the occurrence of the events, and a second section is positioned to be sensed by the sensor. The sensor is positioned adjacent to the second section and includes a first area having a first sensed characteristic, and a second area having a second sensed characteristic. The first event causes the arm to move in a first manner with the first sensed characteristic being sensed by the sensor. The second event causes the arm to move in a second manner with the second sensed characteristic being sensed by the sensor.

In one embodiment, the different sensed characteristics include openings positioned within the arm. The sensed characteristics may also include other characteristics that can be differentiated including capacitance, magnetism, thickness, reflectance, and others. The second section of the arm may be positioned at a second end opposite the first section, or at various other locations along the arm. In one embodiment, the first section is detected by the sensor.

DETAILED DESCRIPTION

The present invention is directed to a device, generally illustrated as10inFIG. 1, having an arm20and sensor30that can differentiate two events within an image forming device. The arm20is pivotally mounted to move in different directions upon the occurrence of different events. A section24of the arm20includes a trigger section having an unequal distribution of a sensed characteristic. A first event moves the arm20in a first direction that is sensed by sensor30in a first manner. A second event moves the arm20in a second direction that is sensed by sensor30in a second manner. The sensor30signals a controller60that oversees the image forming process.

Arm20includes a first end22, second end24, and a pivot23as illustrated inFIG. 1. The arm20is positionable between a first position70, second position72, and third position73. In the first position70, the first end22extends into the media path40. The arm20may be sized to extend completely across the media path40, or just partially. The first position70is a “home” position that the arm20assumes when no events are occurring. The first position may be attained by the weighting of the arm20, or a biasing mechanism (not illustrated) that urges the arm20towards this position.

Pivot23is positioned along the length of the arm20. The pivot23may be positioned at a variety of points between the first end22and second end24.

Second end24is located on an opposite side of the pivot23from the first end22.FIG. 2illustrates one embodiment of the second end24having a trigger section25that moves between the sensor30. Trigger section25is divided into a first section26and a second section27by a reference line28. Reference line28may be positioned at a variety of locations along the trigger section25. In one embodiment, the reference line28is a centerline that equally divides the trigger section25.

The first section26and second section27have different characteristics that are sensed and differentiated by the sensor30. In the embodiment ofFIG. 2, the first section26is a solid section, and the second section27includes an opening29. The opening29creates a different transmittance characteristic in the second section27that can be sensed and differentiated from the first section26. In the embodiment ofFIG. 2, sensor30comprises a light beam transmitter32that emits a light beam that is received by a receiver34. When the arm20is in the first position (i.e., no events are occurring), the trigger section25is positioned between the transmitter32and receiver34.

In one embodiment, the reference line28is centered between the transmitter32and receiver34when the arm20is in the first position70. When a first event occurs and the arm20is moved from the first position70to the second position72, the first section26moves across the light beam. When a second event occurs and the arm20is moved from the first position70to the third position73, the second section27moves across the light beam.

FIG. 3Aillustrates the detection signal resulting from the arm20moving from the first position70to the second position72(i.e., first section26moving across the light beam) and then moving back to the first position70. When the arm20is in the first position70, the light beam is blocked resulting in the output being low at time0. As the first event occurs, the arm20begins moving towards the second position with the edge of the first section26moving beyond the beam at time2. At time2, the light beam is no longer blocked and the output signal is high. The arm20remains in the second position72until the end of the first event. The arm20then returns towards the first position70. In the example ofFIG. 3A, the first event ends at time5, and the arm20moves from the second position72towards the first position70. The arm20does not block the light beam until time7as it returns towards the first position70resulting in the output being again low.

FIG. 3Billustrates the detection signal resulting from the arm20moving from the first position70to the third position73(i.e., second section27moving across the light beam). The light beam is blocked when the arm is in the first position70as indicated at time0. As the arm20begins to move at the beginning of the second event, the opening29moves through the light beam at time2and the output becomes high. The arm20moves towards the third position73with the light beam remaining in the opening from time2through time3, and then is again blocked by the remaining portion of the second section27. The arm20then moves a distance such that the second section27clears the light beam at time5. The arm20remains clear of the light beam until the event is complete at time8. The arm20then moves back towards the first position70and the small section blocks the light beam from time10through time11. The signal is again high from time11through time12as the opening29again moves through the light beam. Finally, the output is low as the light beam is again blocked.

FIG. 4illustrates another embodiment of the trigger section25having different opening patterns. The first section26features a single opening29c, and the second section27features a pair of openings29a,29b. The opening patterns allow for differentiating movement of the arm between the first and second positions, and the first and third positions. The opening29may have a variety of different shapes and sizes depending upon the type of sensor30. Openings29may be completely contained within the arm20as illustrated inFIGS. 2 and 4, or may be positioned along an edge of the arm forming an indent along the edge of the arm20. The reference line28may be positioned at a variety of locations, including along a centerline of the trigger section, offset from the centerline, or at a variety of positions along the arm20.

In the embodiments illustrated inFIGS. 2 and 4, the first position70features the arm20at a position to block the sensor30resulting in a low output. Another embodiment features the arm20at the first position such that the sensor30is not blocked resulting in a high output.

The arm20returns to the first position70once an event terminates. The arm20may bounce when returning to the first position at the end of the event. This includes the arm swinging back-and-forth in a pendulum motion through the first position70until finally coming to rest. The controller60includes logic to account for the bounce. In one embodiment, logic assumes a time sequence of about 50 milliseconds for the arm20to resonate and come to rest at the first position70. Dampening may also be included to reduce or eliminate the amount of bounce in the arm20. In one embodiment, the reference line28is positioned away from any openings29such that when the bounce occurs no openings29move within the light beam (i.e., the light beam is blocked by the trigger section25during the entire length of the bouncing).

FIG. 5illustrates another embodiment of the arm20positioned adjacent to two media paths. A first event occurs when a media sheet moves in a first direction along a first media path40a. The media sheet contacts the arm20moving it from the first position70to the second position72. The arm20returns from the second position72to the first position70after the trailing edge of the media sheet moves beyond the arm20. A second event occurs when a media sheet moves in a second direction along a second media path40b. The media sheet contacts the arm20moving it to the third position73until the trailing edge clears at which time it returns.

A variety of different events may cause the arm to move from the first position70. Events may include media sheets moving along a media path40as previously defined. Another event is illustrated inFIGS. 6A and 6Bwhich include the movement of a door90.FIG. 6Aillustrates the door90in a closed orientation. A first event occurs when a media sheet moves along the media path40and moves the arm20from the first position70to a second position72. The arm20movement from the first position is detected by the sensor38. A second event includes the door90moving between closed and open orientations as illustrated inFIG. 6B. When the door is opened, the arm20moves relative to the sensor38. This movement is opposite to that caused by the first event, and is again detected by the sensor38. The movement caused by the first event is differentiated from the second event because of the different directions of arm movement (i.e., the first event causes clockwise arm movement, and the second event causes counter-clockwise arm movement). One embodiment of a detector arm positioned to detect movement of media sheets along a media path and the orientation of a door is disclosed in co-pending U.S. patent application Ser. No. 10/639,358 entitled “Sensor and Diverter Mechanism for an Image Forming Apparatus”, also assigned to Lexmark International, Inc. and filed on the same day as the present application, and incorporated herein by reference in its entirety. Various other events may also cause arm20movement that can be detected and differentiated.

Sensor30is positioned to detect movement of the arm20. The sensor30may be positioned to detect the movement of the second end24, first end22, or some position therebetween. 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, sensor30includes a transmitter32that transmits a light beam that is received by receiver34. 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.FIGS. 6A and 6Billustrate a proximity sensor38that detects movement of the arm20. Sensors may use a variety of techniques to determine the characteristics including transmission sensing, reflectance sensing, capacitance sensing, inductance sensing, and magnetically-based sensing. Each type of sensor30requires that the arm20have distinguishable characteristics in the first and second sections to determine the event type.

Controller60receives the signals from the sensor30to monitor the image forming device. In one embodiment, controller60includes a microprocessor, random access memory, read only memory, and in input/output interface. One type of controller available for use is found in Model No. C750 available from Lexmark International, Inc. of Lexington Ky.

The term “image forming device” and the like is used generally herein as a device that produces images on a media sheet50. 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 referenced above.

In one embodiment, the reference line28may be between the transmitter32and receiver34when the arm20is in the first position70. In another embodiment, the reference line28may extend across a solid section of the trigger section25such that the sensor30is blocked, or may extend across an opening29such that the sensor30is not blocked.

A variety of different sensed characteristics may be included within the arm20. The characteristics may include an opening pattern, magnetic pattern, inductance pattern, capacitance pattern, reflective surface, and thickness of the arm20among others.

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 sensed first and second sections do not completely clear beyond the sensor30. The distinguishable characteristics in the sections move past the sensor, but less than the entire section moves beyond the sensor30. In one embodiment, the arm20assumes a position other than the first position when no events are occurring. In various embodiments, the triggering section25may be positioned at a variety of locations along the arm20other than at the second end. Additionally, there may be no triggering section25but rather the arm itself that is sensed.12. In one embodiment, the first characteristic is measured as a first time signal, and the second characteristic is measured as a second time signal, with the first time signal being different than the second time signal. 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.