Patent Application
20200130973
The subject application generally relates to controlling the timing of the movement of paper in a print engine, and more specifically to controlling pick and registration motors to ensure proper registration of an image on a printed page.
Document processing devices include printers, copiers, scanners and e-mail gateways. More recently, devices employing two or more of these functions are found in office environments. These devices are referred to as multifunction peripherals (MFPs) or multifunction devices (MFDs). As used herein, MFP means any of the forgoing.
MFPs use paper trays to hold paper for printing user print jobs. When an MFP receives a user print job, pick rollers deliver individual sheets of paper from a paper tray to a set of registration rollers where the individual sheet of paper enters the image transfer unit and an image is printed on the sheet of paper. However, paper slippage and other factors may result in a sheet of paper not arriving at the registration rollers at the expect time, or arriving ahead of time. When a sheet of paper arrives late or ahead of time the image on the paper can be mispositioned or a paper jam can occur.
Various embodiments will become better understood with regard to the following description, appended claims and accompanying drawings wherein:
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.
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.
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.
With reference to
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
Referring now also to
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 S1110 and S2112. 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.
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.
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.
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.
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.
