MXPA97002241A - Apparatus and method to determine a level of material in a suminis charter - Google Patents

Abstract

The present invention relates to an apparatus that includes a supply tray having a base on which a plurality of sheets of material are supported, this apparatus defining a path of material through which the sheets of material travel, including this Apparatus: a sheet collecting assembly that includes a movable leaf collector, this collector being configured to move a collected sheet towards the material path, a sensor arranged in association with the material path at a sensor location, this sensor being adapted to detect a sheet running through the material path, and providing an output signal: a processor coupled with each of the picker assembly and the sensor, wherein the processor controls the movement of the movable picker, and receives the output signal from the sensor, and wherein the processor determines a relative position of a further upper sheet of the remainder of the plurality of leaves. of material with respect to the base of the supply tray, based on an initial actuation of the sheet collector to collect the collected sheet, and on a detection of the collected sheet arriving at the sens

Description

APPARATUS AND METHOD TO DETERMINE A LEVEL OF MATERIAL IN A SUPPLY CHARTER BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus capable of detecting a level of paper in a paper supply tray. 2. - Description of Related Art An image forming apparatus, such as an electrophotographic printer, can include a supply tray containing a printing material, such as paper. The material is kept in the supply tray until a print job is requested, and it is transported to an electrophotographic assembly (EP) inside the printer where a latent image is transferred to it. It is usually intended that the sheets of material are transported one by one from the supply tray and through a paper path to the electrophotographic assembly. A supply tray of an image forming apparatus can be configured in different ways. For example, a known configuration includes a supply tray having a bottom plate that is spring loaded from the bottom, and is forced in an upward direction. The bottom plate loaded with spring forces a stack of paper disposed inside the supply tray in an upward direction against a corner shield. A pick-up assembly that may include a pick-up roller engages the top of the top sheet of the paper stack and moves the top sheet toward the paper path. Another type of known supply tray includes a ramp surface or a dam at one end thereof, which is adjacent to the path of the paper in the printer. The paper of the supply tray is not forced in an upward direction, but rather merely lies on the bottom of the supply tray. A picker assembly includes a picker that engages the top of the top sheet in the paper stack, and moves the top sheet up the dike and into the paper path of the printer. A user of an image forming apparatus that includes a supply tray may find it desirable to be alerted regarding the state of the number of sheets of material (or paper level) inside the supply tray, either before or during a job. of impression.

For example, if a supply tray has a capacity of 200 sheets, it may be desirable for a user to be aware that the supply tray is approximately half full or has approximately 100 sheets therein. Furthermore, it may be desirable for a user to be alerted that the supply tray is almost empty, so that he can fill it before a printing job. Moreover, it may be desirable for a user to know that the number of pages printed in a requested print job is larger than the approximate number of sheets in the supply tray. There are different methods and devices to determine the approximate paper level inside a supply tray. All those conventional paper level indicators require that relatively expensive additional hardware be added to the printer to detect the paper level, thereby increasing the cost of the printer. In general, these methods and apparatus are used in conjunction with a supply tray, where the paper rests directly on the bottom of the supply tray. For example, a method that uses an arm that rests on top of the paper stack, and the hardware is used to detect the angle of the arm. These methods for determining a level of paper in a supply tray, use an arm that rests directly on top of a stack of paper in the supply tray. In addition, it is also known to provide a paper level indicator, wherein a paper stack is disposed within a feeder module, such that the rear edges of the paper sheets are arranged at a sharp angle relative to a bottom surface of the feeder module. A light source is arranged on top of the feeder module, and a sensor is disposed on the bottom of the feeder module. As the sheets in the paper stack are used, the sensor receives more of the light that is produced by the light source. The sensor operates a suitable electrical circuit that provides a "low" warning to a user, when the height of the stack is such that the sensor is substantially exposed. This apparatus is described in United States Patent Number 4,928,949 (Ramsey et al.). This apparatus does not use an arm that rests on top of the paper stack inside the supply tray, but still requires the use of multiple duress sensors, thus adding to the cost of the printer. What is needed in the art is an apparatus for detecting a paper level in a supply tray, which does not require a substantial amount of additional hardware.

SUMMARY OF THE INVENTION The present invention provides an apparatus that includes a processor that is connected to a registration sensor arranged in a paper path, and a collection assembly. The processor controls the operation of a picker of leaves of the picker assembly, and receives a signal from the sensor, indicating that a collected sheet is present. The processor determines the relative position of a further upper sheet in a supply tray, based on an initial actuation of the sheet picker and in the detection of the sheet picked up by the sensor. The relative position of the uppermost sheet can be determined based on the elapsed time, or based on the distance the collected sheet travels to reach the sensor. The invention comprises, in a form thereof, an apparatus that includes a supply tray, for containing a plurality of sheets of material. The apparatus defines a material path through which a sheet of material travels. A picker assembly includes a movable picker that is configured to move a sheet of material toward the material path. A sensor is arranged in association with the material path at a particular location, and is adapted to detect a sheet of material that traverses through the material path, and to provide an output signal. A processor connected to each of the pick-up assembly and the sensor controls the movement of the movable pick-up, and receives the output signal from the sensor. The processor determines a relative position of a further upper sheet of the remainder of the plurality of sheets of material with respect to the base of the supply tray, based on an initial actuation of the sheet picker to pick up the collected sheet, and on the detection by the sensor of the collected sheet. An advantage of the present invention, when incorporated, for example, into an image forming apparatus, is that no additional hardware is required on the hardware normally present in the image forming apparatus. Another advantage is that only one sensor is required, which can be placed in one of a number of selected locations in the paper path.

BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned and other characteristics and advantages of the present invention, and the way to obtain them, will become clearer, and the invention will be better understood, referring to the following description of an embodiment of the invention, taken in conjunction with the accompanying drawings, in which: Figure 1 is a schematic side view of one embodiment of the present invention. Figure 2 is a perspective view of the supply tray and a collection assembly shown in Figure 1. Figure 3 is a flow diagram of one embodiment of a method of the present invention for detecting a level of material in a supply tray. Figure 4 is a flow diagram of an alternative method of the present invention for detecting a level of material in a supply tray. The corresponding reference characters indicate corresponding parts through the different views. The exemplification set forth herein illustrates a preferred embodiment of the invention, in one form, and this exemplification should not be construed to limit the scope of the invention in any way.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, and particularly to Figure 1, there is shown an embodiment of an image forming apparatus 10 of the present invention, which is in the form of an electrophotographic printer. The printer 10 includes a supply tray 12, or a collection assembly 14, a sensor 16, and a processor 18. The printer 10 also defines a material path, or paper path, through which the sheets of material travel. , as indicated generally by the arrow 20. A plurality of rollers can be arranged., such as the rollers 22, inside of. the printer 10, along the paper path 20, to guide and / or feed a sheet through a paper path 20. The supply tray 12 includes a plurality of sheets of paper material or sheets 24, which they define a stack of material 26 that is disposed inside the supply tray 12. The material sheets 24 may be in the form of different types of recording material, as is known. The material stack 26 rests directly on the bottom 28 on the supply tray 12. Accordingly, it can be seen that a sheet of material 24 is pulled out from the top of the stack of material 26, which in turn decreases in size. height. A ramp surface or dam 30 is provided at one end of the supply tray 12 adjacent to the paper path 20. In the embodiment shown, the dam 30 is disposed adjacent the end of the supply tray 12, which defines a handle 32 which allows the user to insert or remove the supply tray 12 of the printer 10. The dam 30 is placed at an angle relative to the bottom 28 such that a sheet of material 24 is pushed against it by the collector assembly 14. , it is deflected in an upward direction indicated by the paper path 20. The picker assembly 14 includes a movable picker 34 that rests on top of a sheet of upper material 24 of the stack of material 26. The picker 34, in the embodiment shown , is in the form of a pick-up roller that rotates as indicated by the arrow 36 to move a sheet of material 24 towards the paper path 20. More particularly, the pick-up assembly 14 can be Voting around a pivot point 38, such that the pick roller 34 is caused to rest by the force of gravity against a sheet of upper material 24. A housing of the drive train 40 includes a plurality of gears, pulleys, bands or the like, for transferring the rotating energy from a power source to the take-up roller 34. The power source may be in the form of a motor, such as a stepping motor 42, which forms a part of the take-up assembly 14.; or it can be in the form of a separate motor (not shown) that engages the pick-up assembly 14 using a clutch or the like. The stepping motor 42 is connected to, and controlled by, the processor 18, by means of the conductor 54. Referring now to Figure 2, one embodiment of the picker assembly 14 of the present invention is shown in greater detail. The pick-up assembly 14 rotates about a longitudinal axis of a pivot arrow 44 having a cam 46 at a distal end thereof. The longitudinal axis of the pivot arrow 44 defines a pivot point 38 (Figure 1). The cam 46 engages a projecting surface 48 of the supply tray 12, and can be operated by inserting and removing the supply tray 12 of the printer 10, to oscillate the collector assembly 14 up and out of the way to remove the supply tray 12. The cam 46 can also be coupled with the projecting surface 48 of the supply tray 12, to allow the collection rollers 34 to contact a sheet of upper material 24 when the tray is inserted. of supply 12 in the printer 10. The housing of the drive train 40 includes a plurality of gears (not shown) which interconnect the stepper motor 42 with the output arrows 50 which drive the take-up rollers 34. For the details of a similar transmission train that can be used or adapted for use with the picker assembly 14 of the present invention, reference is made to the United States Patent Application North America with Serial Number 08 / 406,233, entitled "Auto Compensating Paper Feeder" which is assigned to the assignee of the present invention, and incorporated herein by reference. Referring again to Figure 1, the sensor 16 inside the printer 10 is arranged in association with the paper path 20 at a particular location, such that a sheet of material 24 can pass therethrough. For example, the sensor 16 can be located along the path of the paper 20 before the feed rollers 22, as shown by the solid line, or alternatively it can be located along the path of the paper 20 in a point downstream of the feed rollers 22, as indicated by the dotted lines, and identified as the sensor 16A. In some situations, it may be desirable to include a sensor 16 (16A) at each location, but this is not required to practice the invention. The sensor 16 detects a leading edge of a sheet of material 24 that runs through the paper path 20, as the sheet of material 24 passes therethrough. The sensor 16 is connected to the processor 18 via the conductor 52, and provides an output signal to the processor 18 upon detecting the leading edge of a sheet of material 24. In the embodiment shown, the sensor 16 may be an optical or magnetic sensor. , which is operated by moving a mechanical flag such as an arm, on the coupling by the sheet of paper collected, although other sensors can also be used. The processor 18 is generally of known construction, and may include different required or optional hardware, such as a microprocessor, a RAM memory, a data buffer area, and so on. The processor 18 controls the operation of the stepper motor 42, and in turn, controls the movement of the pickup rollers 34. More particularly, the processor 18 provides a signal on the lead 54, which is used to control the operation of stepper motor 42. Processor 18 also receives an output signal from sensor 16, indicating that a leading edge of a sheet of material 24 has been detected. Processor 18 monitors the time and / or travel distance of the sheet of material 24, by monitoring the start of rotation of the pick-up rollers 34 and the output signal from the sensor 16. The processor 18 uses times and / or distances to determine an approximate vertical position of a sheet of material plus top 24 of the stack ^ of material 26 inside the supply tray 12, and with respect to the bottom 28 of the supply tray 12, and in this manner, infers a material level or height of the material stack 26. Those skilled in the art will recognize that the processor 18 could include multiple processors that are in communication with each other. More particularly, it will be appreciated that the time or distance that any particular sheet of material 24 travels before a leading edge 56 thereof reaches sensor 16, increases as the "H" height decreases (FIG. 1) of the material stack 26. This distance can be calculated by monitoring the start of operation of the stepping motor 42, at which time a particular material sheet 24 was collected, and by monitoring an output signal from the sensor 16, by the processor 18. In the embodiment shown in Figure 2, a single step of the stepping motor 42 provides a known output of the stepping motor 42. Moreover, the transmission ratio between the stepping motor output 42 and the stepping rollers 42 Recording 34 is known, and can be easily modified by changing the transmission ratio of the gears disposed within the housing of the drive train 40. Therefore, a single step of the stepper motor 42 provides a known rotation of the pick-up rollers 34. The rotation of the pick-up rollers 34, in turn, can easily be calculated as a distance using their circumference. Each step of the stepping motor 42, in this manner, results in a known movement of a sheet of material 24 along the paper path 20, any slip between the surface of the roll 34 and the sheet 24 being absent. monitoring the number of steps that each sheet of material 24 moves since it was picked up, the number of steps of the stepper motor 42 can be converted relatively easily, or it can be used as, an indication of a distance, upon receipt An output signal from the sensor 16 can also be used. Of course, it is also possible to use a motor operating on a continuous basis at a known rotational speed by monitoring the time from which a sheet of material 24 is picked up, until a signal is received. output from the sensor 16. The time can be converted to a distance by using the known rotational speed of the motor, which in turn can be used for to calculate or infer the distance traveled from a sheet of material collected 24. Also, if the sensor 16 is placed adjacent to the paper path 20 downstream of the rollers 22, where, for example, the sheet of material 24 is being transported by the feed rollers 22, without the aid of the rollers 34, then the passage of time between the start of operation of the rollers 34 and the indication of the presence of the sheet 24 by an output of the sensor 16, can be convert at a distance by the known rotational speeds of the rollers 34, the rotary speeds of the rollers 22, and the circumferences of the rollers 22 and 34. Because before the sheet reaches the rollers 22, the sheet 24 does not it will be traveling at a constant speed, some compensation may be required, by the acceleration characteristics of the roller 34. This can be achieved, for example, by calculating the integral (I) of the surface of the roller. 34 starting from the moment when the movement of the roller 34 (t0) was started, until the time to reach the superficial velocity of the rollers 22 (t,), and adding the integral (I) to a distance (D) that travel the blade during constant speed. This distance (D) corresponds to the constant speed value multiplied by the time elapsed between the point time made of the sensor 16 (t2), and the time (t,). The integral (I) can be calculated either in real time or can be estimated. The processor 18 is connected by a single-line or multi-line conductor 59 to a visual display 58 to display an indication of the paper level of the material stack 26 inside the supply tray 12. This indication may be in the form of a full percentage designation; an empty, almost empty, full designation, or other similar designation; a bar graph and other graphic designation, etcetera. Moreover, in fact, the visual display 58 may be a visual display of a central computer, in addition to, instead of, being incorporated into the printer 10, as shown in Figure 1. The processor 18 is also connected through from a multi-line conductor 62 to a non-volatile memory 60, which is preferably in the form of a read-only memory (ROM), to a programmable non-volatile memory, such as an EEPROM or a volatile memory. Of course, the memory 60 may be separate from the processor 18 as shown, or may also be incorporated with it. The memory 60 may include parameters therein which are associated with the vertical position of a sheet of material 24 inside the supply tray 12. These parameters may correspond to a distance or a time from which a minimum number can be inferred. of sheets of material inside the supply tray 12 (ie, an "Empty" value), or a maximum number of sheets of material 24 inside the supply tray 12 (ie, a "Fill" value) . If only time is used, then tables corresponding to the speed of each printer can be desired. The memory 60 may also include a look-up table, which allows one or more of a plurality of data values corresponding to the output signals from the sensor 16 to be compared to the comparison values of the look-up table. Referring now to Figure 3, a flow diagram of one embodiment of a method of the present invention is shown, to detect a paper level in a supply tray, wherein the sensor is positioned as the sensor 16 of the Figure 1. First, the printer 10 receives a print command, for example, either manually or from a central computer, which includes information on which page source or supply tray this printer 10 will use (block 64). The processor 18 sets a zero count for the number of steps or the time the stepper motor 42 is operated (block 66). The processor 18 then drives the stepping motor 42, which in turn drives the take-up rollers 34 (block 68). The stepper motor 42 is stepped by a step, and the source is increased by a numerical value, such that the total count is equal to the number of steps moved by the stepper motor 42 (block 70). A decision is then made as to whether the sensor 16 has detected the leading edge of the corresponding collected paper sheet (decision block 72) ^ If the sensor 16 has not yet detected the leading edge of the collected paper sheet (i.e. the processor 18 has not received an output signal from the sensor 16 via the conductor 52), then the pick-up roller 34 is moved again by the stepper motor that is staggering 42 (line 74), and again the count is increased by one. On the other hand, if the sensor 16 had detected the leading edge of a sheet of material 24 (line 76), then the data values of the signals received from the sensor 16 by the processor 18, are mathematically operated by using an averaging technique or resolution (block 78). Alternatively, a counter that runs freely, that is increased at a known speed, may be used, where this counter starts to increase at the beginning of the rotation of the roller 34, and continue to increase its count until the sensor 16 detects the front edge 56 of the sheet of material 24. The averaging or resolution techniques are used to prevent an erratic datum value from erroneously causing an indication of the inappropriate paper level to be sent to a user. Namely, the data values corresponding to the output signals received by the processor 18 from the sensor 16, they can be stored in the processor 18, such as in a RAI * ^ memory (not shown). It will be appreciated that it is not possible for some slippage to occur between the pick-up rollers 34 and a top material sheet 24, occasionally resulting in an erratic datum value. The processor 18 performs a mathematical operation on a discrete number N of stored data values, in such a way that the effect of an erratic datum value is reduced. For example, the processor 18 may perform averaging calculation on every four data values (or other discrete number of data values, eg, between 3 and 10 data values) to reduce the effect of an erratic datum value. If the current datum value falls within the range of upper and lower thresholds or of the comparison values stored in a look up table in memory 60, then the average of the N data values above is used as an indication of the level of paper inside the supply tray 12. On the other hand, if the value of the current datum is outside a threshold or of the comparison values stored in the memory 60 (as may occur due to the sliding between the pick-up rollers 34 and the material sheet 24), then the minimum data value of the discrete number of data values is used as an indication of the paper level inside the supply tray 12 (hence the name "resolution"). In embodiments where the memory 60 includes a reprogrammable memory unit, the threshold values can be updated based on factors such as, for example, variations in manufacturing tolerances and wear. Of course, it will be appreciated that other techniques may also be employed to reduce the effect of erratic data values, and are within the scope of this invention. Moreover, for certain applications, it may not even be necessary to consider the aspect of erratic data values. Continuing with the description of Figure 3, the count that is processed using the averaging or resolution technique described above (block 78) becomes an indication of the paper level inside the supply tray 12, such as a percentage indication complete (block 80). Then a determination is made as to whether the paper level changed from one level to another (decision block 82). Of course, you can vary the type of level indication and the level indication sensitivity of one application to another. If the determination from one level change to another is YES (line 84), then the new level indication is passed to a Grid Image Processor or RIP (block 86) of the printer 10 (in FIG. shows the grid image processor), which in turn causes the new paper level indication to be displayed in the visual display 58 of the printer 10 and / or a visual display screen of a central computer (block 88) . Subsequently a determination is made on whether or not additional pages will be printed (decision block 90), passing control back to block 64 via line 92 if the answer is YES and ending at 94 if the answer is NO . On the other hand, if the determination as to whether or not a level change occurred in decision block 82 was NO (line 96), then the control goes directly to decision block 90, with the resulting decision step over whether there are more pages, as described above. Referring now to Figure 4, there is shown a flow chart of an alternative embodiment of the method of the present invention, to detect a paper level in a supply tray, where the sensor is positioned in a manner corresponding to that of the sensor 16A of Figure 1. Although not easily seen in Figure 1, the position of the sensor 16A is intended to correspond to a position where the rear edge of the sheet of material 24 is decoupled from the pick-up rollers 34, before being detected by the sensor 16A. Accordingly, it is necessary that the sheet of material 24 move through the paper path after uncoupling from the pick-up rollers 34, such as by using the rollers 22 in a paper feed assembly. It will be appreciated by those skilled in the art that it may be more desirable to stop the take-up rollers 34 slightly before, or when, the sheet of material 24 is decoupled therefrom, so that the next sheet of material 24 is not move inward on the paper path until desired. The distance traveled by the leading edge of a sheet of collected material 24 before being detected by the sensor 16A, therefore, is a function of both the circumferential distance moved by the gathering rollers 34 before stopping, and the distance moved. by the feed rollers 22 between the stopping of the pick-up rollers 34 and the detection of the front edge of the sheet of material 24 by the sensor 16A. First, the printer 10 receives a print command, for example, either. manually or from a central computer, which includes information on which page source or supply tray that printer 10 will use (block 100). The processor 18 drives the stepping motor 42, which in turn drives the pick-up rollers 34 (block 102). The stepping motor 42 starts from a zero speed, and accelerates to a known speed corresponding to an operative speed of a paper feed assembly, which includes the rollers 22. This acceleration results in the pick-up rollers 34 exhibiting one of a plurality of possible speed ramps or profile curves, as is known. Depending on the particular speed curve exhibited by the pick-up rollers 34, a certain number of steps or a predetermined period of time is present, before the pick-up rollers 34 reach the substantially constant speed at which the set of paper feeding In this way a decision is made as to whether the velocity ramp of the pick-up rollers 34 has been completed or leveled (decision block 104). If the pick-up rollers 34 are still accelerating, that is, the speed ramp of the pick-up rollers 34 has not yet finished, then a wait state results, as indicated by the line 106. On the other hand, if the speed ramp of the pick-up rollers 34 (line 108), the processor 18 establishes a count of zero for a number of steps of the time that the step motor 42 operates (block 110). A decision is then made about whether the sensor 16A has detected the leading edge of the corresponding collected paper sheet (decision block 112). If the sensor 16A has not yet detected the leading edge of the collected paper sheet (i.e., the processor 18 has not received an output signal from the sensor 16A via the conductor 52A), then the count is increased by one ( block 114), and control passes back to decision block 112 via line 116. On the other hand, if sensor 16A has detected the leading edge of a sheet of material 24 (line 118), then control passes either to block 120 if the basis for determining the movement of the gathering rollers 34 is time, or to the block 112 if the basis for determining the movement of the gathering rollers 34 is the distance. It will be appreciated that if the basis for determining the movement of the pickup rollers 34 is the distance, and the control passes from the decision block 112 to the block 122 (as indicated by the ghost line portion of line 118) , then block 120 is not used. In case the value of the account depends on time, then a mathematical conversion is made in block 120, which converts the time (or the count) into a distance, using the speed known rotation of the motor 42 and the pick-up rollers 34. In the block 122, the distance corresponding to the distance a collected paper sheet 24 moves during the speed ramp of the pick-up rollers 34, is added to the moved distance by the sheet of paper corresponding to the value of the "account". In general, this consists of adding a predetermined distance (which is possibly determined in an empirical manner) corresponding to the distance traveled by the sheet of material 24 during the speed ramp of the pick-up rollers 34 (block 124). This processing using an averaging or resolution technique is generally the same as that described with respect to the description of block 78 of Figure 3. The count that is processed using the averaging or resolution technique (block 124) becomes an indication of the paper level inside the supply tray 12, such as a full percent indication (block 126). A determination is then made about whether the paper level changed from one level to another (decision block 128). Of course, the type of level indication and the sensitivity of the level indication from one application to another can be varied. If the determination from one level change to another is YES (line 130), then the new level indication is passed to a grid image processor (block 132) of the printer 10, which in turn causes the new paper level indication to be displayed in the visual display 58 of the printer 10 , and / or on a visual display screen of a central computer (block 134). Subsequently, a determination is made as to whether or not additional pages are to be printed (decision block 136), passing the control back to block 100 by means of line 138 if the answer is YES, and ending at 140 if the answer is not. On the other hand, if the determination as to whether a level change occurred or not in the decision block 128 was NO (line 142), then the control goes directly to the decision block 136, with the resulting decision step on whether there are more pages, as described above. Although this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this invention.

Claims (28)

1. Description. Accordingly, it is intended that this application cover any variations, uses, or adaptations of the invention, using its general principles. Furthermore, it is intended that this application covers the departures of the present description that enter into the known or customary practice in the art to which this invention pertains, and that fall within the limits of the appended claims. NOVELTY OF THE INVENTION Having described the foregoing invention, it is considered as a novelty, and therefore, property is claimed as contained in the following: CLAIMS 1. An apparatus that includes a supply tray that has a base on which a plurality of sheets of material are supported, this apparatus defining a path of material through which the sheets of material run, including this apparatus: A sheet-collecting assembly that includes a movable leaf-picker, this picker being configured to move a sheet collected towards the material path; a sensor arranged in association with the material path at a sensor location, this sensor adapting to detect a sheet running through the material path, and providing an output signal; A processor coupled with each of the pick-up assembly and the sensor, wherein the processor controls the movement of the movable pick-up, and receives the output signal from the sensor, and wherein the processor determines a relative position of a further upper sheet of the rest of the sensor. the plurality of sheets of material with respect to the base of the supply tray, based on an initial actuation of the sheet picker to collect the collected sheet, and on a detection of the collected sheet arriving at the sensor.
2. 2. The apparatus according to claim 1, characterized in that the position of the uppermost sheet corresponds to a height of the rest of the sheets of material inside the supply tray.
3. The apparatus according to claim 1, characterized in that the pick-up assembly further includes a motor, and wherein the movable pick-up includes a pick-up roller, coupling the motor with, and rotatingly driving the pick-up roller, connecting the processor with, and controlling the operation of this engine.
4. The apparatus according to claim 3, characterized in that the motor includes a stepping motor, and wherein the processor determines the position of the sheet collected inside the supply tray, depending on a number of stepping steps of the motor since the collected sheet detected by the sensor was first moved by the pick-up roller.
5. The apparatus according to claim 1, characterized in that the processor determines the relative position of the uppermost sheet inside the supply tray, depending on a time since the collected sheet detected by the sensor moved. first through the leaf collector.
6. 6. The apparatus according to claim 1, characterized in that the processor determines the relative position of the uppermost sheet inside the supply tray, depending on a distance that a collected sheet travels to reach the sensor.
7. The apparatus according to claim 1, characterized in that the collected sheet is transported along the material path by at least one feed roller.
8. The apparatus according to claim 7, characterized in that the location of the sensor is adjacent to the material path and upstream of at least one feed roller.
9. The apparatus according to claim 7, characterized in that the location of the sensor is adjacent to the material path and downstream of at least one feed roller.
10. 10. The apparatus according to claim as claimed in claim 7, characterized in that the movable pick-up includes a rotating pick-up roller.
11. The apparatus according to claim 1, characterized in that the processor provides an output signal that corresponds to the relative position of the most superior sheet of material remaining inside the supply tray.
12. 12. The apparatus according to claim 1, characterized in that the sensor detects a front edge of the collected sheet that travels through the material path.
13. The apparatus according to claim 1, characterized in that the sensor includes one of an optical sensor and a magnetic sensor.
14. The apparatus according to claim 1, characterized in that the processor includes one of an integral non-volatile memory and a separate nonvolatile memory, for storing the parameters associated with the relative position of the uppermost sheet within the supply tray.
15. 15. The apparatus according to claim 1, characterized in that the non-volatile memory includes a programmable non-volatile memory.
16. 16. The apparatus according to claim 1, characterized in that the parameters correspond to one of a distance and a time from which a minimum number of sheets can be inferred inside the supply tray, and a maximum number of sheets inside the supply tray.
17. 17. A method for determining a material level of a stack of material in a supply tray of an apparatus, the apparatus including a collection assembly with a picker monitored and controlled by a processor to pick up a sheet of material from the stack of material , the apparatus defining a material path through which a selected pick sheet travels from the stack of material, including this method the steps of: Providing a sensor arranged in association with the material path at a location, coupling this sensor with the processor; moving the collected sheet from the supply tray to the material path, using the collection assembly; detect the collected sheet that travels through the material path with the sensor; transmitting an output signal from the sensor to the processor, indicating that the presence of the collected sheet has been detected; determine the level of material inside the supply tray, using the processor, depending on the output signal of the sensor and the initial actuation of the sheet collector to pick up a sheet.
18. 18. The method according to claim 17, characterized in that the step of determining, further includes the step of determining a distance that travels the sheet collected to reach the sensor.
19. 19. The method according to claim 17, characterized in that the step of determining, further includes the step of determining a time since the collected sheet detected by the sensor was first moved by the picker.
20. 20. The method according to claim 17, which includes the additional steps of repeating in sequence the steps of moving, detecting, transmitting, and determining.
21. The method according to claim 20, which includes the additional steps of storing a look-up table in a memory, and comparing at least one data value corresponding to at least one transmitted output signal, with a comparison value in the stored query table.
22. 22. The method according to claim 21, characterized in that the at least one data value includes a plurality of data values, and which includes the additional step of performing a mathematical operation on a discrete number of the plurality of data values.
23. 23. The method according to claim 22, characterized in that the mathematical operation includes at least one of a sum and a division.
24. 24. The method according to claim 22, characterized in that the discrete number of stored data values is selected from a range between 3 and 10 stored data values.
25. 25. The method according to claim 22, which further includes the step of averaging the discrete number of the plurality of data values.
26. 26. The method according to claim 22, which further includes the step of establishing a range of threshold values, wherein, if a current datum value falls within this range of threshold values, then the processor uses an average of that discrete number of the plurality of data values to effect an indication of the material level in the supply tray.
27. 27. The method according to claim 21, which further includes the step of establishing a range of threshold values, and the at least one data value includes a plurality of data values, wherein, if a value The current datum falls outside that range of threshold values, then the processor uses a minimum data value of a discrete number of the plurality of data values, to effect the indication of the material level in the supply tray.
28. 28. An apparatus that includes a supply tray having a base on which a plurality of sheets of material are supported, defining this; apparatus a material path through which the sheets of material travel, including this apparatus: A movable leaf-picker assembly that includes a leaf picker, this picker being configured to move a pick-up sheet toward the material path; a sensor arranged in association with the path of the material in a location of the sensor, the sensor adapting to detect a sheet that travels through the material path, and providing an output signal, - a processor coupled with each of the picker assembly and the sensor, wherein the processor monitors and controls the movement of the movable pick-up, and receives the output signal from the sensor, and wherein this processor determines a relative position of a further upper sheet of the remainder of the plurality of sheets of material with regarding the base of the supply tray, based on the supervision of the sheet collector that collects the collected sheet, and on the detection of the collected sheet that reaches the sensor.