SYSTEM AND METHOD FOR CONSISTENT PAPER MOVEMENT

Abstract

A system and method for consistent paper movement includes a pick/feed motor configured to rotate a pick/feed roller of a print engine to deliver a sheet of paper to the registration nip of a registration roller. A first sensor and a second sensor disposed in the paper path between the pick/feed roller and the registration roller detect the leading edge of the paper. A controller receives sensor data from the first and second sensors and compares the sensor data with expected times for receiving the sensor data. When the received sensor data indicates that the paper is lagging or leading, the controller calculates a period of time to drive the drive the pick/feed motor at a higher or lower speed to compensate for the lagging or leading of the paper.

Claims

1. An apparatus, comprising: a registration motor configured to rotate a registration roller of an associated print engine; a pick/feed motor configured to rotate a pick/feed roller of the print engine and deliver a sheet of paper to the registration roller; a first sensor disposed in a paper path between the pick/feed roller and the registration roller configured to detect a leading edge of the paper; a second sensor disposed in the paper path configured to detect the leading edge of the paper subsequent to the first detector; and a controller configured to receive a sensor data from the first sensor, compare the sensor data with an expected time for receiving the sensor data, determine, based on the compare operation, when the received sensor data indicates that the paper is lagging, calculate a period of time to operate the pick/feed motor at a higher speed to compensate for the lagging of the paper, operate the pick/feed motor at a higher speed for the calculated period of time.

2. The apparatus of claim 1, wherein the pick/feed motor is a variable speed pick/feed motor and wherein the controller is further configured to calculate the higher speed necessary to compensate for the lagging of the paper.

3. The apparatus of claim 2, wherein the controller is further configured to determine, based on the compare operation, when the received sensor data indicates that the paper is leading, calculate a second period of time to operate the pick/feed motor at a lower speed to compensate for the leading of the paper, calculate the lower speed necessary to compensate for the leading of the paper, and operate the pick/feed motor at the calculated lower speed for the second calculated period of time.

4. The apparatus of claim 1, wherein the controller is further configured to determine, based on the compare operation, when the received sensor data indicates that the paper is leading, calculate a second period of time to stop the pick/feed motor to compensate for the leading of the paper, stop the pick/feed motor for the second calculated period of time.

5. The apparatus of claim 1, wherein the controller is further configured to receive a second sensor data from a second sensor sensor, compare the second sensor data with an expected time for receiving the second sensor data, determine, based on the compare operation, when the received second sensor data indicates that the paper is lagging, calculate a second period of time to operate the pick/feed motor at a higher speed to compensate for the lagging of the paper, and operate the pick/feed motor at a higher speed for the second calculated period of time.

6. The apparatus of claim 1, wherein the controller is further configured to determine a deskew time, rotate the registration motor and the registration roller in a reverse direction to deskew the paper for the determined deskew time, and rotate the registration motor and registration roller in a forward direction, after the deskew time, to advance the paper to an image transfer unit of a printer.

7. The apparatus of claim 1, further comprising: a motor driver configured to receive a pulse width modulated signal and a direction signal from the controller for each of the registration motor and the pick/feed motor, and drive the associated registration motor and the pick/feed motor in accordance with the associated pulse width modulated signal and the direction signal.

8. The apparatus of claim 7, further comprising: a multifunction peripheral including the controller further comprising a processor and an associated memory, and a print engine comprising the registration roller, the registration motor, the pick/feed roller, the pick/feed motor, the first sensor, the second sensor, and the motor driver.

9. A multifunction printer, comprising: a print engine operable to perform a print operations, comprising a registration motor configured to rotate a registration roller, a pick/feed motor configured to rotate a pick/feed roller configured to deliver a sheet of paper to the registration roller, a first sensor disposed in a paper path between the pick/feed roller and the registration roller configured to detect a leading edge of the paper, and a second sensor disposed in the paper path configured to detect the leading edge of the paper subsequent to the first detector; and a controller configured to operate the pick/feed motor at a first speed, receive sensor data from the first sensor and the second sensor, compare a receive time of the sensor data with an expected receive time, determine, based on the compare operation, when the receive time of the sensor data indicates that the paper is leading or lagging, calculate a period of time to operate the pick/feed motor at a second speed to compensate for the leading or lagging of the paper, operate the pick/feed motor at a second speed from normal for the calculated period of time.

10. The multifunction printer of claim 9, wherein second speed is selected from the group consisting of a variable higher speed, a variable lower speed, a higher speed, and a stopped or zero speed.

11. The multifunction printer of claim 9, wherein the controller is further configured to determine a deskew time, rotate the registration motor and the registration roller in a reverse direction to deskew the paper for the determined deskew time, and rotate the registration motor and registration roller in a forward direction, after the deskew time, to advance the paper to an image transfer unit of a printer.

12. The multifunction printer of claim 9, wherein the motor driver is configured to receive a pulse width modulated signal and a direction signal from the controller for each of the registration motor and the pick/feed motor, and drive the associated registration motor and the pick/feed motor in accordance with the associated pulse width modulated signal and the direction signal.

13. A method, comprising: driving, by a controller, a pick/feed motor at a normal speed to place a sheet of paper in a paper path of a print engine; sensing, by a first sensor, a leading edge of the sheet of paper; sending, by the first sensor, a first signal to a controller associated with the print engine; sensing, by a second sensor, the leading edge of the sheet of paper; sending, by the second sensor, a second signal to the controller; calculating, by the controller, a first expected time associated with the first signal and a second expected time associated with second signal; receiving, by the controller, the first signal; comparing, by the controller, an arrival time of the first signal with the first expected time; determining, by the controller and based on the compare operation, when the paper is lagging; calculating, by the controller, a period of time to operate the pick/feed motor at a higher speed to compensate for the lagging of the paper; and operating, by the controller, the pick/feed motor at the higher speed for the calculated period of time.

14. The method of claim 13, wherein the pick/feed motor is a variable speed pick/feed motor and further comprising: determining the higher speed based in conjunction with the operation of calculating the period of time to operate the pick/feed motor at a higher speed.

15. The method of claim 13, further comprising: determining, by the controller and based on the compare operation, when the paper is leading; calculating, by the controller, a second period of time to operate the pick/feed motor at a lower speed to compensate for the leading of the paper; and operating, by the controller, the pick/feed motor at the lower speed for the calculated second period of time.

16. The method of claim 15, wherein the pick/feed motor is a variable speed pick/feed motor and further comprising: calculating, by the controller, the lower speed necessary to compensate for the leading of the paper; and operating, by the controller, the pick/feed motor at the calculated lower speed for the second calculated period of time.

17. The method of claim 13, further comprising: determining, by the controller and based on the compare operation, when the paper is leading; calculating, by the controller, a second period of time to stop the pick/feed motor to compensate for the leading of the paper; and stopping, by the controller, the pick/feed motor for the calculated second period of time.

18. The method of claim 13, further comprising: receiving, by the controller, the second signal; comparing, by the controller, an arrival time of the second signal with the second expected time; determining, by the controller and based on the compare operation, when the paper is lagging; calculating, by the controller, a second period of time to operate the pick/feed motor at a higher speed to compensate for the lagging of the paper; and operating, by the controller, the pick/feed motor at the higher speed for the calculated second period of time.

19. The method of claim 18, further comprising: determining, by the controller and based on the compare operation, when the paper is leading; calculating, by the controller, a third period of time to operate the pick/feed motor at a lower speed to compensate for the lagging of the paper; and operating, by the controller, the pick/feed motor at the lower speed for the calculated second period of time.

20. The method of claim 18, further comprising: determining, by the controller and based on the compare operation, when the paper is leading or lagging; calculating, by the controller, a deskew time to compensate for the leading or lagging; rotating, by the controller, the registration motor in a reverse direction to cause the registration rollers to deskew the paper for the calculated deskew time; and rotate the registration motor in a forward direction, after the deskew time, to advance the paper by the registration rollers to an image transfer unit of a printer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Various embodiments will become better understood with regard to the following description, appended claims and accompanying drawings wherein:

[0005] FIG. 1 is a block diagram of an embodiment of a paper feed system;

[0006] FIG. 2 is a diagram of the paper path for a print engine;

[0007] FIG. 3 is a timing diagram of a paper feed system;

[0008] FIG. 4 is a timing diagram illustrating deskew timing of the paper feed system;

[0009] FIG. 5 is a flowchart of example operations of an embodiment of a variable speed paper feed control system; and

[0010] FIG. 6 is a flowchart of example operations of an embodiment of a dual speed paper feed control system.

DETAILED DESCRIPTION

[0011] The systems and methods disclosed herein are described in detail by way of examples and with reference to the figures. It will be appreciated that modifications to disclosed and described examples, arrangements, configurations, components, elements, apparatuses, devices methods, systems, etc. can suitably be made and may be desired for a specific application. In this disclosure, any identification of specific techniques, arrangements, etc. are either related to a specific example presented or are merely a general description of such a technique, arrangement, etc. Identifications of specific details or examples are not intended to be, and should not be, construed as mandatory or limiting unless specifically designated as such.

[0012] In an example embodiment, an apparatus includes a registration motor configured to rotate registration rollers of an associated print engine, and a pick/feed motor that is configured to rotate a pick/feed roller of the print engine to deliver a sheet of paper to the registration nip of the registration rollers. A first sensor and a second sensor disposed in the paper path between the pick/feed roller and the registration roller detect the leading edge of the paper. A controller receives sensor data from the first and second sensors and compares the received sensor data with expected times for receiving the sensor data. When the received sensor data indicates that the paper is lagging, the controller calculates a period of time to drive the drive the pick/feed motor at a higher speed to compensate for the lagging of the paper. When the received sensor data indicates that the paper is leading, the controller calculates a period of time to drive the pick/feed motor at a lower speed, or stop the pick/feed motor, to compensate for the leading of the paper.

[0013] Embodiments herein provide for varying the operation of the pick/feed and registration motors based on sensed paper positions as a sheet of paper is fed by the pick/feed rollers to the registration rollers to ensure that sheets of paper arrive at the registration nip of the registration rollers at the expected time. Delivery of sheets of paper to the registration nip at the expected time ensures proper operation of the print engine, helps to reduce the occurrence of paper jams, and ensure proper registration of images when the sheets are forwarded by the registration rollers to the image transfer unit.

[0014] With reference to FIG. 1, an example paper feed control system 100 is presented. Paper 104 is picked up from a paper tray 104 by pick/feed rollers 108 and delivered to a registration nip of registration rollers 114. The registration rollers 114 feed the paper 104 to the next stage 116 in the print engine, for example the image transfer unit. The paper path 106 takes the paper 104 past two sensors S1 110 and S2 112 that provide a controller 130 with signals about the position of the paper 104 in the paper path 106. The controller 130 also receives signals from a pick roll encoder 118 associated with the pick/feed rollers 108.

[0015] The controller 130 controls the dual brush motor driver 120 that drives the pick/feed motor 122 and the registration motor 126. The controller 130 sends Pulse Width Modulation (PWM) control signals to the dual brush motor driver 120 along with a direction signal for each motor 122, 126. Varying the duty cycle of the PWM signal results in varying voltages values at the output of the dual brush motor driver 120, where a 100% duty cycle results in the maximum speed and a 0% duty cycle stops rotation of the associated motor 122, 126. The varying voltage changes the speed of the associate motor 122, 126. The pick/feed motor 122 drives the pick/feed rollers 108 through an associated pick/feed gearbox 124. The registration motor 126 drives the registration rollers 114 through an associated registration gearbox 128. The controller 130 receives signals from encoders in the pick/feed motor 122 and the registration motor 126. Control of the motors 122, 126 by the controller 130 is explained in detail below with regard to FIGS. 2 and 3.

[0016] Referring now also to FIG. 2, a cross sectional view of the paper feed path of a print engine 200 is illustrated, and corresponding timing diagrams are illustrated in FIGS. 3 and 4. FIG. 4 is a partial diagram of FIG. 3 for illustrating with particularity the timing described below. The paper path 206, illustrated by the arrowed lines, starts with a paper 202 being picked up by pick/feed rollers 208 from a paper tray 204 when the pick/feed motor turns on in the forward direction as illustrated in FIGS. 3 and 4. Alternatively the paper 202 can be fed from a sheet bypass feed (not shown). The leading edge of the paper 202 is directed through a separation nip that ensures that only one sheet of paper 202 is passed through to the registration rollers 214. As the paper 202 is passed from the pick/feed rollers 208 to the registration rollers 214, the leading edge of the paper 202 first encounters switch S1 210 and then switch S2 212, placing each switch 201, 212 in the on position, illustrated as positions X and Y in FIG. 4. When the paper passes S2 212, the registration motor turns the registration rollers 214 in the reverse direction as illustrated by position Y in FIG. 4. Turning the registration rollers 214 in the reverse direction facilitates deskewing of the paper 202. As the paper 202 is pushed into the registration nip of the registration rollers 214, the pick/feed rollers 208 continue to push the paper 202 forward and a bubble is formed by the paper 202. The registration motor then turns the registration rollers 214 in the forward direction as illustrated by position Z in FIG. 4 and the paper 202 is moved to the next stage, for example to the image transfer unit. When the registration motor is turned in the forward direction, the pick/feed rollers 208 are turned off and only the registration rollers 214 move the paper 202.

[0017] When operating normally, the leading edge of the paper 202 is delivered to the registration nip at the proper time to allow both a short period of time for deskewing and the paper 202 to moved forward at the proper time by the registration rollers 214. However, factors such as paper slipping can result in a paper 202 not arriving at the proper time. To compensate, the controller can vary the speed of the pick/feed motor to speed up or slow down the paper feed process based on the actual versus expected times that the leading edge of the paper 202 arrives at sensors S1 110 and S2 112. By speeding up or slowing down the pick/feed motor, the controller can compensate for the leading or lagging and substantially or entirely eliminate the leading or lagging.

[0018] FIG. 5 is a flowchart of example operations of an embodiment of a variable speed paper feed control system 500. The variable speed paper feed control system 500 advantageously permits paper feed control in situations where the pick and registration motors can be operated at variable speeds. The process begins at start block 502 and proceeds to block 504 where the expected times from the pick roller to S1, S2, and the registration nip are calculated. For example, the expected times can be predetermined and retrieved from memory, or calculated based on current or predicted operation of the printer. At block 506, the pick motor is turned on at the normal speed to pick a page of paper from the paper tray. At block 508, the process waits until the leading edge of the paper picked from the paper tray passes the first sensor, S1. Once the paper passes the first sensor, S1, progress is made to block 510. At block 510, if the paper arrived at the first sensor, S1, after the expected time that was calculated at block 504, then the paper is determined to be lagging and progress is made to block 512 where the pick motor speed is recalculated for a higher speed, after which progress is made to block 516. If the paper arrived at the first sensor, S1, before the expected time that was calculated at block 504, then the paper is determined to be leading and progress is made to block 514 where the pick motor speed is recalculated for a lower speed, and progress is made to block 516.

[0019] At block 516, the process waits until the leading edge of the paper passes the second sensor, S2. Once the paper passes the second sensor, S2, progress is made to block 518. At block 518, if the paper arrived at the second sensor, S2, after the expected time that was calculated at block 504, then the paper is determined to be lagging and progress is made to block 520 where the pick motor speed is recalculated for a higher speed. In an embodiment, in block 520 the deskew time can be increased to allow time for the paper to arrive at the registration nip and be properly deskewed. Progress is then made to block 524. If the paper arrived at the second sensor, S2, before the expected time that was calculated at block 504, then the paper is determined to be leading and progress is made to block 522 where the pick motor speed is recalculated for a lower speed. Because the paper is determined to be leading, the paper may reach the registration nip and start to bubble before anticipated. Therefore, in block 522, the deskew time can be adjusted so that the paper deskews properly. Progress is then made to block 524 where after a fixed deskew time the registration rollers are turned to forward the paper to the next stage.

[0020] FIG. 6 is a flowchart of example operations of an embodiment of a dual speed paper feed control system 600. The dual speed paper feed control system 600 advantageously permits paper feed control in situations where one or more of the motors is operable only using discrete speeds, such as a high and a low speed, rather than variable speeds as for the motors in the variable speed paper feed control system 500 of FIG. 5. As would be understood in the art, the system can be adapted to motors capable of more than two discrete speeds, or combinations of motors capable of variable and discrete speeds.

[0021] Operation of the dual speed paper feed control system 600 begins at start block 602 and proceeds to block 604 where the expected times from the pick roller to S1, S2, and the registration nip are calculated as described above. At block 606, the pick motor is turned on at the normal speed to pick a page of paper from the paper tray. At block 608, the process waits until the leading edge of the paper picked from the paper tray passes the first sensor, S1. Once the paper passes the first sensor, S1, progress is made to block 610. At block 610, if the paper arrived at the first sensor, S1, after the expected time that was calculated at block 604, then the paper is determined to be lagging and progress is made to block 612. At block 612, the pick motor speed is operated at high speed for a calculated period of time to advance the page, after which the pick motor speed is returned to normal speed. Progress is then made to block 616. If the paper arrived at the first sensor, S 1, before the expected time that was calculated at block 604, then the paper is determined to be leading and progress is made to block 614. At block 614, the pick motor speed is paused for a calculated period of time to slow transfer of the page, after which the pick motor speed is returned to normal speed. Progress is then made to block 616.

[0022] At block 616, the process waits until the leading edge of the paper passes the second sensor, S2. Once the paper passes the second sensor, S2, progress is made to block 618. At block 618, if the paper arrived at the second sensor, S2, after the expected time that was calculated at block 604, then the paper is determined to be lagging and progress is made to block 620. At block 620, the pick motor speed is operated at high speed for a calculated period of time to advance the page, after which the pick motor speed is returned to normal speed. In an embodiment, in block 620 the deskew time can be increased to allow time for the paper to arrive at the registration nip and be properly deskewed. Progress is then made to block 624. If the paper arrived at the second sensor, S2, before the expected time that was calculated at block 604, then the paper is determined to be leading and progress is made to block. At block 622, the deskew time is adjusted so that the paper will deskew properly. For example, extra deskew time can be added. In a configuration, the pick motor can be briefly stopped and then return to normal speed. Progress is then made to block 624 where after a fixed deskew time the registration rollers are turned to forward the paper to the next stage.

[0023] In light of the foregoing, it should be appreciated that the present disclosure significantly advances the art of paper feed control for printers. While example embodiments of the disclosure have been disclosed in detail herein, it should be appreciated that the disclosure is not limited thereto or thereby inasmuch as variations on the disclosure herein will be readily appreciated by those of ordinary skill in the art. The scope of the application shall be appreciated from the claims that follow.