The system described below relates to printers in which an image is transferred from an image receiving surface to a recording medium, and, more particularly, to printers in which the image is transferred to the recording medium as the medium passes through a nip between a transfix roller and an image receiving member.
Modern printers use a variety of inks to generate images from data. These inks may include liquid ink, dry ink, also know as toner, and solid ink. So-called “solid ink” refers to ink that is loaded into a printer as a solid, which is typically in stick or pellet form. The solid ink is melted within the printer to produce liquid ink that is supplied to a print head for ejection onto media or an intermediate member to generate a printed image from image data. These solid ink printers typically provide more vibrant color images than toner or liquid ink jet printers.
A schematic diagram for a typical solid ink imaging device is illustrated in
In previously known printers, the transfix roller is moved into and out of engagement with the print drum by the operation of stepper motors coupled to the transfix roller through cams, levers, and/or other force multiplying devices that require a fulcrum or the like. The motor force needed to move moment arms capable of producing 600 to 2200 pounds of total transfix force is substantial. In some cases, more than one motor is required for reliable operation of the transfix roller. Additionally, the cams and levers may also require bearings and springs for proper operation. These mechanical force multiplying components require lubrication and periodic inspection to ensure they are aligned correctly. Noise may also arise from the frictional engagement of the parts with one another. The mechanical interaction of these parts may also limit the speed at which the parts may be moved as repeated movement at faster speeds necessary for higher throughput rates may subject the mechanical parts to higher temperatures and affect the operational life of the components. Consequently, a quieter and simpler mechanism for moving a transfix roller is needed.
A hydraulic system controls engagement of a transfix roller with an image receiving member in a printer. The system includes a motor having an output shaft, a translational member having a first end and a second end, one of the first and the second ends being mechanically coupled to the output shaft of the motor so the motor output shaft moves the translational member in a linear path, a hydraulic translator coupled to the other end of the translational member so movement of the translational member in the linear path displaces hydraulic fluid within the hydraulic translator to move a pair of links in a linear direction, a transfix roller having a first end and a second end, the first and the second ends of the transfix roller being mechanically coupled to the pair of links so the displacement of the hydraulic fluid within the hydraulic translator moves the transfix roller in the linear direction towards and away from an image receiving member, and a controller electrically coupled to the motor to send a motor control signal to the motor for controlling direction and speed of the motor output shaft.
The transfer roller control system may be incorporated in a printer. Such a printer includes a frame and an image receiving member rotatably secured to the frame. The printer also includes a print head for applying print to the print drum to form an image on the print drum and a transfix roller. The transfix roller has a first end and a second end. The transfix roller cooperates with the image receiving member to form a nip between the transfix roller and the image receiving member. The printer also includes a feeder for advancing media into the nip and a system for controlling engagement of the transfix roller with the image receiving member in the printer. The system includes a motor having an output shaft and a translational member having a first end and a second end. One of the first and the second ends is mechanically coupled to the output shaft of the motor so the motor output shaft moves the translational member in a linear path. The system also includes a hydraulic translator coupled to the other end of the translational member so movement of the translational member in the linear path displaces hydraulic fluid within the hydraulic translator to move a pair of links in a linear direction. The first and the second ends of the transfix roller are mechanically coupled to the pair of links so the displacement of the hydraulic fluid within the hydraulic translator moves the transfix roller into and out of engagement with an image receiving member. The system also includes a controller electrically coupled to the motor to send a motor control signal to the motor for controlling direction and speed of the motor output shaft.
Features of the transfer roller control system are apparent to those skilled in the art from the following description with reference to the drawings, in which:
The term “printer” refers, for example, to reproduction devices in general, such as printers, facsimile machines, copiers, and related multi-function products. While the specification focuses on a system that rotates the transfix roller in solid ink printers, the system may be used with any printer that uses a belt or roller to assist in transferring the image to media. In particular, the system may be well suited for use in selectively engaging a fuser roll into and out of engagement with an image receiving member of a printer using toner.
A system 10 for controlling engagement of a transfix roller 12 with an image receiving member 14 in a printer 16 is shown in
While the motor described in the exemplary embodiment shown in the figures is a motor producing rotational output power, other types of motors may be used as well. For example, a motor producing a linear reciprocating output may be used. In such an embodiment, the motor may directly drive the piston of the master cylinder or a linear force linkage that drives the piston of the master cylinder.
The system 10 incorporates a motor that provides rotational output and further includes a translational member 24 having a first end 26 and an opposed second end 28. The first end 26 is mechanically coupled to the output shaft 20 of the motor 18 so that rotation of the motor output shaft 20 moves the translational member 24 in a linear direction, for example, along the direction of arrows 30. The translational member 24 may be any member capable of converting the rotation of output shaft 20 into linear motion. As shown in
To permit the rotation of the output shaft 20 of motor 18 with improved linear speed control of the rack 24, a speed reducer 32 is positioned between the output shaft 20 and rack 24 such that the linear motion of the rack 24 may be optimized. Alternatively, the rack 24 may be moved in the direction of arrows 30 by a direct connection (not shown) of the rack 24 to the output shaft 20. The speed reducer 32 may, as shown in
The speed reducer 32 serves to reduce the rotational speed of output shaft 20 so the first cylindrical structure 43 rotates at a rotational speed that is less than that of the output shaft 20 of the motor 18. For example, the second cylindrical structure 46 may have a diameter that is larger than the diameter of the motor timing pulley 40. The speed reduction ratio may be described as ratio of the diameters of the pinion gear and the motor pulley, and may, for example, be around four to eight, or perhaps six. The use of a timing belt 44 having teeth 45 to engage the teeth on the motor timing pulley 40 and the teeth 52 on the pinion gear 42 provides very accurate angular positioning of the pinion gear 42 with respect to the output shaft 20. In particular, slippage and other inaccuracies in rotational speed may be limited. The timing belt 44, however, may be replaced with a toothless belt and the motor timing pulley 40 and the pinion gear 42 may be replaced with pulleys. For example, the belt may be in the form of flat or V-type belt that rides in a groove around the circumference of a pulley.
Referring again to
The hydraulic translator 54 may have any suitable form capable of providing hydraulic fluid 56 to move the links 58 and 60 in the direction of arrows 62. For example, and as shown in
The hydraulic translator 54 of the system 10, as shown in
The slave cylinders 80 and 82 are in fluid communication with the master cylinder 72 by the conduit 78. Each of the slave cylinders 80 and 82 has a piston, for example, pistons 84. The slave cylinders 80 and 82 may be secured to the frame for the printer 16 for proper support. One end 83 of a piston 84 reciprocates within the slave cylinders 80 and 82 in response to the displacement of a diaphragm 99 (
While the hydraulic translator 54 has been described as having a pair of slave cylinders 80 and 82, an embodiment having a solitary slave cylinder (not shown) with a mechanical linkage (not shown) may be used to move the transfix roller 12 with links 58 and 60. The mechanical linkage to connect the solitary slave cylinder would need to be adapted to provide equal force on each of the links such that the transfix roller 12 is evenly and uniformly moved towards and away from the image receiving member 14.
The system 10 may further include a transducer 88 in fluid communication with the hydraulic fluid within the hydraulic translator 54. The transducer 88 is utilized for generating an electronic signal corresponding to a pressure of the hydraulic fluid 56. The signal is received by, for example, the controller 68. As shown in
The links 58 and 60 may have any suitable shape. As shown in
Those skilled in the art will recognize that numerous modifications can be made to the specific implementations described above. Therefore, the following claims are not to be limited to the specific embodiments illustrated and described above. The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.