Patent Publication Number: US-2021162779-A1

Title: Variable radius pulleys

Description:
BACKGROUND 
     Inkjet printers can deposit quantities of printing fluid onto a printable media (e.g., paper, plastic, etc.). In some examples, inkjet printers can create a curl and/or cockle in the printed media when the printing fluid droplets are deposited by the inkjet printer. In some examples, a number of physical properties of the printable media can be changed when the printing fluid droplets are deposited by the inkjet printer. For example, the stiffness of the printable media can be changed when the printing fluid droplets are deposited by the inkjet printer. The curl, cockle, and/or other physical properties that change due to the printing fluid droplets can make document finishing processes difficult. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example variable radius pulley consistent with the present disclosure. 
         FIG. 2  illustrates an example variable radius pulley consistent with the present disclosure. 
         FIG. 3  illustrates an example variable radius pulley consistent with the present disclosure. 
         FIG. 4  illustrates an example variable radius pulley consistent with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     A number of systems and devices for a variable radius pulley are described herein. In one example, a media puller device can include a variable radius pulley coupled to a drag roller, and a cable coupled to the variable radius pulley to maintain a torque on the drag roller as the cable wraps around the variable radius pulley. In some examples, a system for a variable radius pulley can include a variable radius pulley that includes a spiral section, a drag roller coupled to the variable radius pulley to receive print media, a cable coupled to the variable radius pulley to wrap around the spiral section, and a spring coupled to the cable to apply a resistive force when the cable wraps around the spiral section. 
     In some examples, a finishing device described herein can include a media puller that includes a first drag roller and a second drag roller to clamp received print media, a variable radius pulley coupled to the first drag roller, wherein the variable radius pulley includes a spiral section that alters a radius of the variable radius pulley as the variable radius pulley rotates, a cable coupled to the variable radius pulley to wrap around the spiral section when the received print media is released from the first drag roller and the second drag roller, and a spring coupled to the cable to apply a resistive force when the cable wraps around the spiral section. 
     The systems and devices described herein can include a drag roller that applies a consistent force on the print media when the print media is removed from the media puller. The consistent force can prevent distorting properties of the print media when the print media is partially dried inkjet media. Previous systems and devices can include a drag roller that applies increasing force as the media is removed from the media puller. In some examples, the force applied to the print media can correspond to a distance the print media travels across the drag roller. The present disclosure includes a variable radius pulley coupled to the drag puller so that the drag puller applies consistent force on the print media despite the distance the print media travels across the drag roller. 
     In some examples, the systems and devices for a variable radius puller can be utilized by a finisher of an inkjet printing device that generates partially dried inkjet media. The inkjet printing device can include a print zone to deposit a printing fluid on a print media. The print zone of the inkjet printing device can deposit the printing fluid to generate partially dried inkjet media. In some examples, the partially dried inkjet media can provide difficulties when stacking, aligning, and/or finishing. 
     For example, the partially dried inkjet media can have distorted properties such as a curl, a cockle, a reduction in stiffness, increased surface roughness, extruding or protruding fibers from the surface, misaligned fibers, and/or increased sheet to sheet friction of the media. In some examples, these distorted properties can be caused by printing fluid deposited on the media and the media absorbing the printing fluid. For example, the printing fluid can be in a liquid state that can be absorbed by a media such as paper. In this example, the liquid state of the printing fluid can cause the distorted properties of the media in a similar way that other liquids may distort the properties of the media. 
     The systems and devices for a variable radius pulley described herein can be utilized by a media puller of a finisher of an inkjet printing device. In some examples, the media puller can be utilized to stack the partially dried inkjet media of an inkjet printing device. As described herein, the variable radius puller can be coupled to a drag roller to maintain a force provided by the drag roller on the partially dried inkjet media as the partially dried inkjet media travels across the drag roller. In this way, additional property distortions from the drag roller can be prevented by maintaining a force applied to the partially dried inkjet media. 
     The figures herein follow a numbering convention in which the first digit corresponds to the drawing figure number and the remaining digits identify an element or component in the drawing. Elements shown in the various figures herein may be capable of being added, exchanged, and/or eliminated so as to provide a number of additional examples of the present disclosure. In addition, the proportion and the relative scale of the elements provided in the figures are intended to illustrate the examples of the present disclosure, and should not be taken in a limiting sense. 
       FIG. 1  illustrates an example variable radius pulley  102  consistent with the present disclosure. In some examples,  FIG. 1  can illustrate a system  100  that includes a variable radius pulley  102  coupled to a drag roller  104 . In some examples, the variable radius pulley  102  can be utilized to provide resistance and/or force on print media clamped by the system  100 . For example, the variable radius pulley  102  can be coupled to a side of the drag roller  104  such that rotation of the variable radius pulley  102  also rotates the drag roller  104 . 
     In some examples, the variable radius pulley  102  can include a spiral section. In some examples, the spiral section decreases a radius of the variable radius pulley  102  as the cable  108  wraps around the variable radius pulley  102 . In some examples, the spiral section can include a plurality of different radii  110 - 1 ,  110 - 2 ,  110 - 3 ,  110 - 4 ,  110 - 5  to maintain a torque applied to the drag roller  104 . In some examples, the radius of the variable radius pulley  102  can alter for each angle of rotation by the variable radius pulley  102 . For example, a first angle of rotation can occur between radius  110 - 1  and radius  110 - 2 . In this example, the radius of the variable radius pulley  102  can decrease during the first angle of rotation. That is, the radius  110 - 1  can be greater than the radius  110 - 2 . In another example, a second angle of rotation can occur between radius  110 - 2  and radius  110 - 3 . In this example, the radius can decrease during the angle of rotation between radius  110 - 2  and radius  110 - 3 . In this example, the radius  110 - 2  can be greater than the radius  110 - 3 . As used herein, an angle of rotation is a measurement of an amount of angular rotation. 
     In some examples, the variable radius pulley  102  can be coupled to a cable  108  via a cable connector  106 . The cable connector  106  can permanently or semi-permanently couple the cable  108  to a particular position of the variable radius pulley  102 . For example, the cable connector  106  can couple the cable  108  to a position that wraps a portion of the cable around the variable radius pulley  102 . In this example, the cable connector  106  can couple the cable  108  such that the cable  108  is in contact with the variable radius pulley  102  from the cable connector  106  to a first radius  110 - 1  of the variable radius pulley  102 . In this example, a torque on the drag roller  104  can be affected by the first radius  110 - 1  of the variable radius pulley  102 . In some examples, the spiral section decreases a radius at a cable/pulley surface contact point (e.g., cable contact point, etc.) of the variable radius pulley  102  as the cable  108  wraps around the variable radius pulley  102 . As used herein, the cable/pulley surface contact point or cable contact point is a point where the cable  108  stops contacting the variable radius pulley  102 . For example, the cable/pulley surface contact point can be at the first radius  110 - 1  of the variable radius pulley  102 . 
     In some examples, the cable  108  can be connected to a spring or other type of resistance device to provide a resistive force or spring force on the variable radius pulley  102 . In some examples, the system  100  can include a print media puller that can pinch a piece of print media utilizing the drag roller  104 . In some examples, the print media can be released when the print media interacts with a registration surface. In these examples, the media can rotate the drag roller  104  and variable radius pulley  102  in a clockwise direction as illustrated in  FIG. 1 . 
     In some examples, the variable radius pulley  102  can include a spiral section to alter a radius of the variable radius pulley  102 . For example, the variable radius pulley  102  can include a plurality of different radii  110 - 1 ,  110 - 2 ,  110 - 3 ,  110 - 4 ,  110 - 5  to lower a radius of the variable radius pulley  102  as the print media rotates the drag roller  104  in the clockwise direction. For example, the variable radius pulley  102  can rotate in a clockwise direction and wrap the cable  108  around a cylinder of the variable radius pulley  102 . In this example, the radius of the cylinder can decrease from the first radius  110 - 1  to an n+1 radius  110 - 5 . In some examples, the first radius  110 - 1  can be a first distance that is greater than a second radius  110 - 2 , the second radius  110 - 2  can be a distance that is greater than a third radius  110 - 3 , the third radius  110 - 3  can be a distance that is greater than a fourth radius  110 - 4 , and the fourth radius  110 - 4  can be a distance that is greater than an n+1 radius  110 - 5 . 
     As described herein, the cable  108  can be coupled to a spring or other type of resistance device. In some examples, the spring coupled to the cable  108  can increase a force applied to the cable  108  as the cable wraps around the variable radius pulley  102 . For example, as the spring stretches when the cable  108  wraps around the variable radius pulley  102 , the force the spring applies to the cable  108  can be increased. In some examples, the variable radius pulley  102  can counter the increased force of the spring by decreasing the radius to provide a consistent torque applied to the drag roller that applies a constant force to the print media. 
     In some examples, a torque applied to the drag roller  104  can be maintained despite an angle of rotation from the variable radius pulley  102 . For example, the torque for each angle of rotation can be calculated utilizing Equation 1. Equation 1 can include a torque (T) that can be calculated by multiplying the spring force (Fspring) and a corresponding pulley radius (Rpulley) of the variable radius pulley  102 . For example, the Rpulley 1 can be the radius  110 - 1  of the variable raidus pulley  102  and the Fspring 1 can be the corresponding spring force of a spring coupled to the cable  108 . In this example, the torque (T) of the radius  110 - 1  and the corresponding spring force can be equal to the torque (T) of the raidius  110 - 2  (Rpulley 2) and a corresponding spring force (Fspring 2). 
         T =Fspring 1×Rpulley1=Fspring 2×Rpulley 2 =Fspring  N ×Rpulley  N   Equation 1
 
       FIG. 2  illustrates an example variable radius pulley  202  consistent with the present disclosure. In some examples, the system  200  can be a portion of a media puller of a finisher coupled to an inkjet printing device. For example, the system  200  can be a portion of a media puller that can receive partially dried inkjet media from a print zone of the inkjet printing device and transport the partially dried inkjet media from a first side of the finisher to a second side of the finisher for stacking the partially dried inkjet media. In some examples, the partially dried inkjet media can be distorted if a torque on a drag roller exceeds a torque threshold. In some examples, the system  200  can utilize a variable radius pulley  202  to maintain a torque below a torque threshold for the partially dried inkjet media. 
     In some examples, the system  200  for a variable radius pulley  202  can include a variable radius pulley  202  that includes a spiral section, a drag roller  204  coupled to the variable radius pulley  202  to receive print media, a cable  208  coupled to the variable radius pulley  202  to wrap around the spiral section, and a spring  212  coupled to the cable  208  to apply a resistive force when the cable  208  wraps around the spiral section. As described herein, the spiral section can be a cylinder of the variable radius pulley that includes a plurality of radii for altering a torque on the drag roller  204 . In some examples, the radius of the variable radius pulley  202  can decrease as the cable  208  wraps around the spiral section of the variable radius pulley  202 . In some examples, the radius of the spiral section can be altered during a rotation when the cable  208  wraps around the spiral section. In some examples, the rotation can be a single rotation. 
     In some examples, the variable radius pulley  202  can be coupled to a cable  208  via a cable connector  206 . The cable connector  206  can permanently or semi-permanently couple the cable  208  to a particular position of the variable radius pulley  202 . For example, the cable connector  206  can couple the cable  208  to a position that wraps a portion of the cable around the variable radius pulley  202 . In this example, the cable connector  206  can couple the cable  208  such that the cable  108  is in contact with the variable radius pulley  202  from the cable connector  106  to a particular radius of the variable radius pulley  202 . 
     In some examples, the spring  212  can include a spring constant. In some examples, the spring constant can be between 1 gram per millimeter and 5 grams per millimeter. In a specific example, the spring constant for the spring  212  can be 3 grams per millimeter. In some examples, the spring  212  can include a spring force. For example, the spring  212  can include a spring force between 20 grams and 40 grams. In a specific example, the spring  212  can include a spring force of 31 grams. In some examples, the spring  212  can be stretched when print media is removed from the system  200  and passes across the drag roller  204 . In some examples, the spring force of the spring  212  can increase when the spring is stretched, when the cable  208  wraps around the variable radius pulley  202 , and/or when the drag roller  204  is moving in a clockwise direction as illustrated in  FIG. 2 . 
     In some examples, the spiral section decreases a radius at a cable/pulley surface contact point (e.g., cable contact point, etc.) of the variable radius pulley  202  as the cable  208  wraps around the variable radius pulley  202 . As used herein, the cable/pulley surface contact point or cable contact point is a point where the cable  208  stops contacting the variable radius pulley  202 . For example, the cable/pulley surface contact point can be at a particular radius of the variable radius pulley  202 . 
     As described herein, the drag roller  204  can have a constant torque level when releasing the print media. The torque on the drag roller  204  can be calculated utilizing a radius of the variable radius pulley  202  and a spring force of the spring  212 . For example, the torque on the drag roller  204  can be calculated by multiplying the spring force of the spring  212  and a radius of the variable radius pulley  202 . In this example, the radius of variable radius pulley  202  can decrease as the spring force of the spring  212  increases. In this way, the calculated torque on the drag roller  204  can stay constant as the drag roller  204  rotates clockwise when releasing the partially dried inkjet media as described herein. 
       FIG. 3  illustrates an example variable radius pulley  302  consistent with the present disclosure. In some examples, the system  300  can be a portion of a media puller of a finisher coupled to an inkjet printing device. For example, the system  300  can be a portion of a media puller that can receive partially dried inkjet media  316  from a print zone of the inkjet printing device and transport the partially dried inkjet media  316  from a first side of the finisher to a second side of the finisher for stacking the partially dried inkjet media  316 . In some examples, the partially dried inkjet media  316  can be distorted if a torque on a drag roller  304  exceeds a torque threshold. In some examples, the system  300  can utilize a variable radius pulley  302  to maintain a torque on the drag roller  304  so a force is below a force threshold for the partially dried inkjet media  316 . 
     In some examples, a finishing device described herein can include a media puller that includes a first drag roller  304  and a second drag roller  314  to clamp received print media  316 , a variable radius pulley  302  coupled to the first drag roller  304 , wherein the variable radius pulley  302  includes a spiral section that alters a radius of the variable radius pulley  302  as the variable radius pulley  302  rotates, a cable  308  coupled to the variable radius pulley  302  to wrap around the spiral section when the received print media  316  is released from the first drag roller  304  and the second drag roller  314 , and a spring  312  coupled to the cable  308  to apply a resistive force when the cable  308  wraps around the spiral section. 
     In some examples, the variable radius pulley  302  can be coupled to a cable  308  via a cable connector  306 . The cable connector  306  can permanently or semi-permanently couple the cable  308  to a particular position of the variable radius pulley  302 . For example, the cable connector  306  can couple the cable  308  to a position that wraps a portion of the cable around the variable radius pulley  302 . In this example, the cable connector  306  can couple the cable  308  such that the cable  308  is in contact with the variable radius pulley  302  from the cable connector  306  to a particular radius of the variable radius pulley  302 . As described herein, the particular radius can be altered as the variable radius pulley  302  rotates in a clockwise direction as illustrated in  FIG. 3 . 
     In some examples, the spring  312  can include a spring constant. In some examples, the spring constant can be between 1 gram per millimeter and 5 grams per millimeter. In a specific example, the spring constant for the spring  312  can be 3 grams per millimeter. In some examples, the spring  312  can include a spring force. For example, the spring  312  can include a spring force between 20 grams and 40 grams. In a specific example, the spring  312  can include a spring force of 31 grams. In some examples, the spring  312  can be stretched when print media  316  is removed from between the first drag roller  304  and the second drag roller  314 . As described herein, the print media  316  can rotate the first drag roller  304  in a clockwise direction and rotate the second drag roller  314  in a counter clockwise direction as illustrated in  FIG. 3 . In some examples, the spring force of the spring  312  can increase when the spring is stretched, when the cable  308  wraps around the variable radius pulley  302 , and/or when the drag roller  304  is moving in a clockwise direction as illustrated in  FIG. 3 . 
     The torque on the drag roller  304  can be calculated utilizing a radius of the variable radius pulley  302  and a spring force of the spring  312 . For example, the torque on the drag roller  304  can be calculated by multiplying the spring force of the spring  312  and a radius of the variable radius pulley  302 . In this example, the radius of variable radius pulley  302  can decrease as the spring force of the spring  312  increases. In this way, the calculated torque on the drag roller  304  can stay constant as the drag roller  304  rotates clockwise when releasing the partially dried inkjet media as described herein. 
       FIG. 4  illustrates an example variable radius pulley  402  consistent with the present disclosure. In some examples, the system  400  can be a portion of a media puller of a finisher coupled to an inkjet printing device. For example, the system  400  can be a portion of a media puller that can receive partially dried inkjet media from a print zone of the inkjet printing device and transport the partially dried inkjet media from a first side of the finisher to a second side of the finisher for stacking the partially dried inkjet media. In some examples, the partially dried inkjet media can be distorted if a torque of a drag roller  404  exceeds a torque threshold. In some examples, the system  400  can utilize a variable radius pulley  402  to maintain a torque below a torque threshold for the partially dried inkjet media. 
     In some examples, the variable radius pulley  402  can be coupled to the drag roller  404  via a shaft  420 . The shaft  420  can be positioned through a center portion of the variable radius pulley  402  and through a center portion of the drag roller  404  to synchronize the rotation of the variable radius pulley  402  and the drag roller  404 . For example, rotation of the drag roller  404  can rotate the variable radius pulley  402  a same rotational distance when the drag roller  404  and variable radius pulley  402  are coupled by the shaft  420 . 
     In some examples, the variable radius pulley  402  can be coupled to a cable  408  via a cable connector  406 . The cable connector  406  can permanently or semi-permanently couple the cable  408  to a particular position of the variable radius pulley  402 . For example, the cable connector  406  can couple the cable  408  to a position that wraps a portion of the cable around the variable radius pulley  402 . In this example, the cable connector  406  can couple the cable  408  such that the cable  408  is in contact with the variable radius pulley  402  from the cable connector  406  to a particular radius of the variable radius pulley  402 . As described herein, the particular radius can be altered as the variable radius pulley  402  rotates in a clockwise direction as illustrated in  FIG. 4 . 
     In some examples, a finishing device described herein can include a media puller that includes a first drag roller  404  and a second drag roller  414  to clamp received print media, a variable radius pulley  402  coupled to the first drag roller  404 , wherein the variable radius pulley  402  includes a spiral section  422  that alters a radius  410 - 1 ,  410 - 2  of the variable radius pulley  402  as the variable radius pulley  402  rotates, a cable  408  coupled to the variable radius pulley  402  to wrap around the spiral section  422  when the received print media is released from the first drag roller  404  and the second drag roller  414 , and a spring coupled to the cable  408  to apply a resistive force when the cable  408  wraps around the spiral section  422 . 
     The torque on the drag roller  404  can be calculated utilizing a radius of the drag roller  404  and a spring force of the spring. For example, the torque on the drag roller  404  can be calculated by multiplying the spring force of the spring and a radius of the variable radius pulley  402 . In this example, the radius of variable radius pulley  402  can decrease as the spring force of the spring increases. In this way, the calculated torque on the drag roller  404  can stay constant as the drag roller  404  rotates clockwise when releasing the partially dried inkjet media as described herein. 
     In some examples, the torque on the drag roller  404  can be a constant torque despite a rotational distance of the variable radius pulley  402  and/or a stretch distance of the spring. As described herein, the radius of the variable radius pulley  402  can be a position where the cable  408  contacts the variable radius pulley  402 . For example,  FIG. 4  illustrates when the cable  408  is positioned at radius  410 - 1 . In this example, the cable  408  can wrap around the variable radius pulley  402  and contact the variable radius pulley  402  at radius  410 - 2 . In some examples, the radius  410 - 1  can be a greater distance than radius  410 - 2 . As described herein, a spring coupled to the cable  408  can be stretched when the cable  408  wraps around the variable radius pulley  402 . In some examples, when the spring is stretched a resistance or spring force provided by the spring can increase. In these examples, the radius of the variable radius pulley  402  can decrease to maintain a constant torque despite the stretch distance of the spring and/or the rotational distance of the variable radius pulley  402 . 
     The above specification, examples and data provide a description of the method and applications, and use of the system and method of the present disclosure. Since many examples can be made without departing from the spirit and scope of the system and method of the present disclosure, this specification merely sets forth some of the many possible example configurations and implementations.