Patent Publication Number: US-2022219466-A1

Title: Manual media sheet insertion at duplex reversal point of duplex printing path

Description:
BACKGROUND 
     Printing devices can be standalone printers that have just printing functionality, or multifunction peripherals (MFPs), multifunction devices (MFDs), and all-in-one (AIO) printing devices that combine printing functionality with other functionality, such as scanning, copying, and faxing functionality. Printing devices can use a variety of different technologies, including inkjet and laser technologies. Printing devices print using print material, such as colorant like ink or toner, to form images on print media like sheets of paper. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A, 1B, and 1C  are diagrams of an example printing device having a C- or U-shaped duplex printing path with a duplex reversal point at which a media sheet can be manually inserted into the printing device. 
         FIGS. 2A and 2B  are diagrams of an example printing device having an S-shaped duplex printing path with a duplex reversal point at which a media sheet can be manually inserted into the printing device. 
         FIGS. 3A and 3B  are diagrams of an example control and a media guide ramp of a printing device to assist with manual media sheet insertion at a duplex reversal point of a duplex printing path of the device. 
         FIGS. 4A, 4B, and 4C  are diagrams of an example control and media sheet edge guides to assist with manual media sheet insertion at a duplex reversal point of a duplex printing path of the device. 
         FIG. 5  is a flowchart of an example method for printing using a printing device having a duplex printing path with a duplex reversal point at which a media sheet can be manually inserted into the printing device. 
         FIG. 6  is a diagram of an example computer-readable data storage medium for a printing device having a duplex printing path with a duplex reversal point at which a media sheet can be manually inserted into the printing device. 
         FIG. 7  is a block diagram of an example printing device having a duplex printing path with a duplex reversal point at which a media sheet can be manually inserted into the printing device. 
     
    
    
     DETAILED DESCRIPTION 
     Printing devices can form images on print media by outputting colorant, such as toner or ink, onto the media. A printing device may be able to print on a variety of different types of print media, such as standard-weight office or copy paper, higher quality and heavier bond paper, inkjet paper that is adapted for inkjet printing, photo paper (including inkjet photo paper) that is adapted for printing photographs, and so on. Even among print media of the same type, like bond paper, there may be different sub-types, such as letterhead bond paper and blank bond paper. 
     Printing devices can include removable or fixed input trays in which print media is loaded. During printing of the pages of a print job, a printing device may “pick” and print on successive sheets of media from an input tray. One tray of a printing device may be loaded with print media of the type that the device is most often used to print on. 
     Different printing devices have different approaches for printing on multiple print media types. A printing device may have multiple input trays, such as a higher-capacity tray for loading media of the type that the device is most often used to print on, and a lower-capacity tray for loading media of types that are less frequently printed on, such as photo paper. The lower-capacity tray may in fact be integrated on the higher-capacity tray, for loading just a single media sheet at a time. Adding additional input trays to a printing device can increase manufacture cost, however, even if the trays are integrated with a higher-capacity tray. 
     Therefore, another approach is for a printing device to simply forego additional input trays. To print on print media of a different type than the media currently loaded in the tray, a user may have to remove the currently loaded media from the tray and replace it with the media of the different type. If the input tray is removable, the user may first have to remove the tray from the printing device before switching the type of media loaded in the tray, and then reinsert the tray into the device. 
     If the printing device “picks” sheets for printing from the top of the print media stack in the input tray, the user may just add media of a different type if it has a similar size as the type already in the tray. However, the user may still have to remove the tray from the printing device before adding media of the different type. Thus printing on different types of media can be time-consuming and inconvenient. 
     A printing device may instead have different input trays for different media types. If the printing device&#39;s input tray is removable, the user thus removes the installed input tray from the device and in its place inserts the supplemental input tray having media of the different type. When printing on the different media type is finished, the user may then switch back in the original tray. While this process is more convenient than using the same input tray for multiple media types, it is expensive and inconvenient because the user has to acquire and keep track of another input tray. 
     Described herein are techniques to provide a way by which media sheets can be inserted into a printing device having automatic duplex printing capability, and which ameliorate the above noted and other shortcomings. The automatic duplex printing capability permits the device to print on both sides of a media sheet automatically, without requiring the user to reload the media sheet back into the device after the first side has been printed on so that the device can print on the second side of the sheet. The techniques described herein leverage the duplex printing path of the automatic duplex printing capability to receive manual insertion of a media sheet at a duplex reversal point of the path. 
       FIGS. 1A, 1B, and 1C  show an example printing device  100  having a C- or U-shaped duplex printing path with a duplex reversal point at which a media sheet can be manually inserted into the printing device  100 . The printing device  100  can be a standalone printer or a printing device having other functionality in addition to printing functionality. The printing device  100  can be an inkjet-printing device, a laser-printing device, or a printing device that uses another type of printing technology. 
     As depicted in  FIGS. 1A, 1B, and 1C , the printing device  100  can include an input tray  102  for loading media sheets  128  into the device  100 . In some examples, there may be one input tray in the printing device  100  (the tray  102 ), or there may be multiple input trays, including the tray  102 . The input tray  102  may be fixed and thus non-removable from the printing device  100 , or it may be removably insertable into the device  100 . In the latter case, the input tray  102  may be referred to as a cassette. 
     The printing device  100  can include an output tray  104 . The output tray  104  collects media sheets  128  after they have advanced through and output from the device  100 . In the techniques described herein, the output tray  104  can also serve as an input tray in a manual insertion mode of the device  100 , in which a media sheet is manually inserted at a duplex reversal point of a duplex printing path of the device  100 . 
     The printing device  100  can include a print engine  106  that ejects colorant, like ink or toner, as the media sheets  128  advance past and incident to the engine  106  through the device  100 . The print engine  106  may be an inkjet-printing engine that jets ink, a laser-printing eject that outputs toner, or a different type of print engine using a different type of colorant, to form images on the media. The print engine  106  may be a monochromatic print engine that can print in just one color, such as black to form black-and-white images, or may be a color printing engine that can print in multiple colors to form full-color images. 
     The printing device  100  may include a media sensor  108 . The media sensor  108  can detect presence (and thus absence as well) of the media sheets  128  as they advance past and incident to the sensor  108 . The printing device  100  can include rollers  110 ,  112 ,  114 ,  116 , and  118 . At least the rollers  114 ,  116 , and  118  are reversibly rotatable, being able to rotate both clockwise and counter-clockwise. The rollers  110 ,  112 ,  114 ,  116 , and  118  advance the media sheets  128  through the device  100  along various paths. Although five such rollers  110 ,  112 ,  114 ,  116 , and  118  are depicted in  FIGS. 1A, 1B, and 1C , the device  100  may have more or fewer such rollers. 
     The printing device  100  can include media guides  122  and  124 , which guide the media sheets  128  along various paths as the sheet  128  advances through the device  100 . Although two such guides  122  and  124  are depicted in  FIGS. 1A, 1B, and 1C , the device  100  may have more or fewer such guides. The device  100  can include other components as well, in addition to and/or in lieu of those depicted in  FIGS. 1A, 1B, and 1C . 
       FIG. 1A  shows a simplex printing path  130  of the printing device  100 . The simplex printing path  130  is the path beginning at a simplex entry point  131  and along which media sheets  128  advance from the input tray  102  and past the print engine  106 . When the media sheets  128  advance past the print engine  106 , the engine  106  can print on the sides of the sheets  128  that face the engine  106 . These sides of the sheets  128  are the sides that face down in the input tray  102 . 
     To advance a media sheet  128  along the simplex printing path  130 , the roller  110 , which can be referred to as a pick roller, “picks” or advances the top-most sheet  128  from the stack of sheets loaded in the input tray  102  by rotating clockwise, and advances the sheet  128  in the direction indicated by the arrow  132 , towards the roller  112 . The guide  120  guides the media sheet  128  toward the roller  112 . As the roller  112  engages and advances the sheet  128  by rotating clockwise, the guide  120  guides the media sheet  128  in the direction indicated by the arrow  134 , towards the guide  126 . 
     The guide  126  guides the media sheet  128  in the direction indicated by the arrow  134 , towards the rollers  114  and  116 . The rollers  114  and  116  engage and advance the sheet  128  by respectively rotating clockwise and counter-clockwise. The media sheet  128  advances between the rollers  114  and  116 , still in the direction indicated by the arrow  134 , past the print engine  106  and then past the media sensor  108  towards the roller  118 . As the sheet  128  advances past the print engine  106 , the engine  106  can output colorant onto the media sheet  128 . The roller  118 , rotating clockwise, engages and advances the sheet  128  outward from the print engine  106 , in the direction indicated by the arrow  136 . The media sensor  108  detects that the sheet  128  has reached the end of the simplex printing path  130 . 
     In a simplex mode of the printing device  100 , the roller  118  outputs the media sheet  128  onto the output tray  104 . Specifically, the roller  118  advances the sheet  128  until it no longer engages the media sheet  128 , ejecting the sheet  128  from the simplex printing path  130  of the device  100  onto the tray  104 . In the simplex mode, the printing device  100  thus prints on one side of the media sheet  128  as the sheet  128  advances from the input tray  102  through the simplex printing path  130 , specifically the side facing down when the sheet  128  is in the tray  102 . 
       FIG. 1B  shows a duplex printing path  150  of the printing device  100 . The duplex printing path  150  is the path along which media sheets  128  advance from a duplex reversal point  160  at the beginning of the path  150 . The media sheets  128  are flipped over along the duplex printing path  150 , so that the print engine  106  can print on the sides of the sheets  128  opposite to the sides that face the engine  106  when initially advancing along the path  150 . 
     In a duplex mode of the device  100 , the roller  118  reversibly draws a media sheet  128  back into the printing device  100  after the sheet  128  has advanced through the simplex printing path  130  of  FIG. 1A . Instead of outputting the sheet  128  onto the output tray  104  as in the simplex mode, the roller  118  switches rotational direction. The duplex reversal point  160  is thus the point at which the media sheet  128  is drawn back into the printing device  100  for advancement through the duplex printing path  150  for second-side printing, after the sheet  128  has been first-side printed during advancement through the simplex printing path  130 . 
     The roller  118 , rotating counter-clockwise, advances the media sheet  128  in the direction indicated by the arrow  152 , past the media sensor  108  and the print engine  106  and toward the rollers  114  and  116 . The media sensor  108  can detect when the sheet  128  has been completely reversed drawn back into the printing device  100  in the duplex mode. The rollers  114  and  116  engage and advance the media sheet  128 , by respectively rotating counter-clockwise and clockwise, toward the guide  124  as indicated by the arrow  154 . The guide  124  guides the sheet  128  towards the guide  122 , which guides the media sheet  128  towards the roller  112 . As the roller  112  engages and advances the sheet  128  by rotating clockwise, the guide  120  guides the media sheet  128  in the direction indicated by the arrow  156 , towards the guide  126 . 
     At this point, the duplex printing path  150  becomes the same as the simplex printing path  130  of  FIG. 1A . The guide  126  guides the media sheet  128  in the direction indicated by the arrow  156 , towards the rollers  114  and  116 . The rollers  114  and  116  reverse rotational direction again, engaging and advancing the sheet  128  by respectively rotating clockwise and counter-clockwise. 
     The media sheet  128  advances between the rollers  114  and  116 , still in the direction indicated by the arrow  156 , past the print engine  106  and then past the media sensor  108 , towards the roller  118 . As the sheet  128  advances past the engine  106 , the print engine  106  can output colorant onto the media sheet  128 . The roller  118  reverses rotational direction again, rotating clockwise, to engage and advance the sheet  128  outward from the print engine  106  until the roller  118  has output the media sheet  128  onto the output tray  104  and thus no longer engages the sheet  128 . The media sensor  108  detects that the sheet  128  has reached the end of the duplex printing path  150 . 
     In the duplex mode, the device  100  thus first prints print on one side of the media sheet  128  as it advances from the input tray  102  through the simplex printing path  130  of  FIG. 1A , specifically the side facing down when the sheet  128  is in the tray  102 . Rather than outputting the sheet  128  onto the output tray  104  as in the simplex mode, the device  100  in the duplex mode then reversibly draws the sheet  128  back in at the duplex reversal point  160 . The printing device  100  flips the media sheet  128  over as the sheet  128  advances through the duplex printing path  150 , so that the device  100  can print on the other side of the media sheet  128  before outputting it onto the output tray  104 . 
     The duplex mode is an automatic duplex mode. This means that the printing device  100  can automatically reversibly draw the media sheet  128  back in for printing on the second side of the sheet  128  after the first side of the sheet  128  has been printed. The user does not have to manually insert the media sheet  128  back into the device  100 , or otherwise handle the sheet  128 , for second-side printing after first-side printing of the media sheet  128 . 
     The printing device  100  can include a control  138 , a media sheet guide ramp  140 , and media sheet edge guides  142 . An example implementation of the control  138 , guide ramp  140 , and edge guides  142  is presented later in the detailed description. The control  138  can be a button that is switchably positionable between a pulled-out position in  FIGS. 1A and 1B  and a pushed-in position in  FIG. 1C . When the control  138  is in the pulled-out position, a user can push the control  138  inwards to the pushed-in position, per the arrow  170  of  FIG. 1C , and then pull the control  138  outwards back to the pulled-out position. 
     The media sheet guide ramp  140  is switchably positionable between an unused, recessed position in  FIGS. 1A and 1B  and a used, extended position in  FIG. 1C . When the control  138  is in the pulled-out position, the guide ramp  140  is in the recessed position. Pushing the control  138  inwards to the pushed-in position can raise the ramp  140  upwards from the recessed position to the extended position, per the arrow  172  of  FIG. 1C . In the extended position, the ramp  140  is tangential to the roller  118  at the duplex reversal point  160 . Pulling the control  138  outwards back to the pulled-out position can cause the ramp  140  to lower back to the recessed position. 
     The media sheet edge guides  142  are switchably positionable between an unused, recessed position in  FIGS. 1A and 1B  and a used, extended position in  FIG. 1C . When the control  138  is in the pulled-out position, the edge guides  142  are in the recessed position. Pushing the control  138  inwards to the pushed-in position can rotate the edge guides  142  upward from the recessed position to the extended position, per the arrow  174  of  FIG. 1C . Pulling the control  138  outwards back to the pulled-out position can cause the edge guides  142  to rotate back inward to the recessed position. 
       FIG. 1C  shows how the duplex printing path  150  of the printing device  100  can be leveraged in a manual insertion mode to receive manual insertion of a media sheet  128  at the duplex reversal point  160  for simplex-printing the sheet  128  without the media sheet  128  having to advance through the simplex printing path  130 . A user may insert a media sheet  128  of a different type into the printing device  100  without having to disturb the stack of media sheets  128  loaded in the input tray  102 . In the implementation of  FIG. 1C , the output tray  104  also serves as an input tray in the manual insertion mode. 
     A user positions the media sheet  128  laterally between the media sheet edge guides  142  extending from the output tray  104 , and pushes the sheet  128  inwards along the extended media sheet guide ramp  140  towards the roller  118 . The edge guides  142  assist lateral positioning of the media sheet  128  during manual insertion of the sheet  128 . That is, the guides  142  ensure that the lateral (e.g., side) edges of the media sheet  128  perpendicular to the leading and trailing edges of the sheet  128  are aligned for correct insertion. 
     The guide ramp  140  guides the media sheet  128  towards the roller  118  during manual insertion of the sheet  128 . The roller  118  engages the media sheet  128  as the sheet  128  is manually inserted at the duplex reversal point  160  by rotating counter-clockwise. The media sheet  128  then advances through the duplex printing path  150  as in  FIG. 1B , for printing on the side of the sheet  128  facing the ramp  140  during manual insertion of the media sheet  128 . 
     The roller  118  thus advances the manually inserted media sheet  128  in the direction indicated by the arrow  152 , past the media sensor  108  and towards the rollers  114  and  116 . The sensor  108  can be used in the manual insertion mode to detect the leading and/or lagging edges of the media sheet  128 , so that the position of the sheet  128  as it advances through the duplex printing path  150  is known. 
     The rollers  114  and  116  engage and advance the media sheet  128 , by respectively rotating counter-clockwise and clockwise, towards the guide  124 , as indicated by the arrow  154 . The guide  124  guides the sheet  128  towards the guide  122 , which guides the media sheet  128  towards the roller  112 . As the roller  112  engages and advances the sheet  128  by rotating clockwise, the guide  120  guides the media sheet in the direction indicated by the arrow  156 , towards the guide  126 . The guide  126  guides the media sheet  128  towards the rollers  114  and  116 , still in the direction indicated by the arrow  156 . The rollers  114  and  116  reverse rotational directional, engaging and advancing the sheet  128  by respectively rotating clockwise and counter-clockwise. 
     The media sheet  128  advances between the rollers  114  and  116 , still in the direction indicated by the arrow  156 , past the print engine  106  and then past the media sensor  108 , towards the roller  118 . As the sheet  128  advances past the engine  106 , the engine  106  can output colorant onto the media sheet  128 . The roller  118  reverses rotational direction, rotating clockwise to engage and advance the sheet  128  outwards from the print engine  106  until the roller  106  has output the media sheet  128  onto the output tray  104  and no longer engages the sheet  128 . 
     The manual insertion mode of the printing device  100  differs from the simplex and duplex modes. In the simplex mode, the device  100  advances a media sheet  128  along the simplex printing path  130  of  FIG. 1A  from the input tray  102  and outputs the sheet  128  onto the output tray  104  after having printed on the side of the media sheet  128  facing down in the input tray  102 . In the duplex mode, the printing device  100  advances a sheet  128  first along the simplex printing path  130  of  FIG. 1A  as in the simplex mode. Instead of outputting the media sheet  128  onto the output tray  104 , however, in the duplex mode the device  100  reversibly draws the sheet  128  back in for printing on the opposite side by advancing the media sheet  128  along the duplex printing path  150  of  FIG. 1B . 
     In the manual insertion mode, the printing device  100  does not reversibly draw a media sheet  128  back into the device  100  for advancement along the duplex printing path  150  of  FIG. 1B  after the sheet  128  has already advanced along the simplex printing path  130  of  FIG. 1A . Rather, the printing device  100  draws in a media sheet  128  manually inserted at the duplex reversal point  160  of the duplex printing path  150  for advancement along the duplex printing path  150  as in  FIG. 1C  (i.e., without the sheet  128  having first advanced along the simplex printing path  130 ). The manual insertion mode thus leverages the duplex printing path  150  provided for the duplex mode. 
     The described techniques provide a manual insertion mode to a printing device, like the printing device  100  of  FIGS. 1A-1C , which may otherwise not have one. The techniques achieve this by leveraging the duplex printing path of the printing device. This is why in the manual insertion mode, the media sheet inserted at the duplex reversal point may have to be flipped over prior to simplex-printing, as in  FIG. 1C . The printing device may not otherwise be able to receive and subsequently simplex-print the media sheet. 
     For example, in the printing device  100  of  FIGS. 1A-1C , the roller  112  may not be reversibly rotatable, and may just be able to rotate clockwise. Therefore, a media sheet manually inserted at the duplex reversal point  160  has to travel along the duplex printing path  150  and thus has to be flipped over prior to being printed on. As another example, the printing device  100  of  FIGS. 1A-1C  may not have any way to receive a manually inserted media sheet other than at the duplex reversal point  160 . 
       FIGS. 2A and 2B  shows an example printing device  100  having an S-shaped duplex printing path with a duplex reversal point at which a media sheet can be manually inserted into the printing device.  FIGS. 2A and 2B  thus show that a duplex printing path can be leveraged in a manual insertion mode, even if the duplex printing path is S-shaped and not C- or U-shaped as in  FIGS. 1A, 1B, and 1C . For descriptive and illustrative clarity and convenience, guides, rollers, and sensors of the printing device  100  are not depicted in  FIGS. 2A and 2B . 
     The printing device  100  of  FIGS. 2A and 2B  can advance a media sheet  128  beginning at the simplex entry point  131  of the simplex printing path  130 . The device  100  thus picks the sheet  128  from the input tray  102 , and advanceably flips the media sheet  128  over per the arrow  202 . The printing device  100  advances the sheet  128  past the print engine  106 , as indicated by the arrow  204 . The print engine  106  can print on the side of the media sheet  128  incident to the engine  106  as the sheet  128  advances past. This is the side of the media sheet  128  facing down when the sheet  128  was in the tray  102 . 
     The printing device  100  again advanceably flips the media sheet  128  over, per the arrow  206 , and then advances the sheet  128  in the direction indicated by the arrow  208 . In the simplex mode, the device  100  outputs the media sheet  128  onto the output tray  104 . In the duplex mode, the printing device  100  instead reversibly draws the sheet  128  back in at the duplex reversal point  160  of the duplex printing path  150 . 
     The duplex reversal point  160  is differently located between  FIGS. 2A and 2B . In the implementation of  FIG. 2A , the duplex reversal point  160  is located at the output tray  104 , as in  FIGS. 1A, 1B, and 1C . In the duplex mode, the printing device  100  therefore advances the sheet  128  in the direction indicated by the arrow  210  after having drawn the media sheet  128  back in at the duplex reversal point  160 . 
     In the implementation of  FIG. 2B , the duplex reversal point  160  is located at a duplex reversal tray  216 . In the duplex mode, the printing device  100  first advances the media sheet  128  upward along the duplex reversal tray  216 , per the arrow  218 . The device  100  then advances the sheet  128  downwards along the duplex reversal tray  216 , per the arrow  220 , after having drawn the media sheet  128  back in at the duplex reversal point  160 . 
     In both  FIGS. 2A and 2B , the printing device  100  advanceably flips the media sheet  128  over per the arrow  212 , and advances the sheet in the direction indicated by the arrow  214 . The duplex printing path  150  then becomes the same as the simplex printing path  130 . The device  100  flips the sheet  128  over per the arrow  202 , and advances the media sheet  128  past the print engine  106 , as indicated by the arrow  204 . 
     The print engine  106  can print on the side of the media sheet  128  incident to the engine  106  as the sheet  128  advances past. This is the side opposite the side of the media sheet  128  that the engine  106  printed on when the sheet  128  advanced along the simplex printing path  130 . The printing device  100  advanceably flips the media sheet  128  over, per the arrow  206 , and advances the sheet  128  in the direction indicated by the arrow  208  before putting the media sheet  128  onto the output tray  104 . 
     The duplex printing path  150  of  FIGS. 2A and 2B  can be leveraged to receive manual insertion of a media sheet  128  at the duplex reversal point  160  in a manual insertion mode, for simplex-printing the sheet  128  without having to advance the media sheet  128  through the simplex printing path  130 . In  FIG. 2A , the output tray  104  serves as an input tray in the manual insertion mode, and may include a control, a media sheet guide ramp, and/or media sheet edge guides as in  FIGS. 1A, 1B, and 1C . In  FIG. 2B , the duplex reversal tray  216  serves as this input tray, and therefore may include such a control, media sheet guide ramp, and/or media sheet edge guides. 
     The techniques described in relation to printing devices like those of  FIGS. 1A-1C, 2A, and 2B  provide for a manual insertion mode in which a media sheet is flipped over prior to simplex-printing. That is, the techniques leverage a duplex printing path in a manual insertion mode such that a media sheet is inserted at a duplex reversal point, flipped over, and then simplex-printed. However, the techniques may be employed in conjunction with printing devices other than those shown in  FIGS. 1A-1C, 2A, and 2B . 
     For example, a printing device may have a duplex printing path in which a media sheet can be manually inserted at a duplex reversal point in a manual insertion mode for simplex-printing without having to flip the sheet. The media sheet therefore travels along a portion of the duplex printing path and not the entirety of the duplex printing path as described above. Such a printing device may have a C- or U-shaped duplex printing path similar to  FIGS. 1A-1C , or a S-shaped duplex printing path similar to  FIG. 2A or 2B . 
     For instance, in the context of a printing device having a C- or U-shaped duplex printing path similar to  FIGS. 1A-1C , a media sheet may be manually insertable at the duplex reversal point  160  of  FIG. 1C  and drawn into the printing device  100 . Once the lagging edge of the sheet has advanced past the print engine  106 , the media sheet is reversed in direction back out the device  100 . As the sheet advances past the print engine  106 , the engine  106  prints on the sheet. The media sheet is thus simplex-printed after manual insertion at the duplex reversal point  160 , without having to be flipped over. 
     Similarly, in the context of a printing device having an S-shaped duplex printing path similar to  FIG. 2A or 2B , a media sheet may be manually insertable at the duplex reversal point  160  of  FIG. 2A or 2B  and drawn into the printing device  100 . Rather than advancing along the part of the duplex printing path  150  indicated by the arrow  212 , the sheet may advance along the parts of the path  150  indicated by the arrows  206  and  204 , but in the opposite direction. Once the lagging edge of the media sheet has advanced past the print engine  106 , the sheet reverses and advances in the direction of the arrows  204 ,  206 , and  208 . The sheet is thus simplex-printed after manual insertion at the duplex reversal point  160 , without having to be flipped over. 
       FIGS. 3A and 3B  show an example of the control  138  and the media guide ramp  140  in detail.  FIG. 3A  shows the guide ramp  140  in the unused, recessed position.  FIG. 3B  shows the guide ramp  140  in the used, extended position. The guide ramp  140  is rotatable about a pivot point  302 .  FIGS. 3A and 3B  show the control  138  as a triangular button, but the button may instead be rectangular or another shape. 
     To switch the media guide ramp  140  from the recessed position of  FIG. 3A  to the extended position of  FIG. 3B , the control  138  is pushed in, as indicated by arrow  304  in  FIG. 3B . The control  138  engages the guide ramp  140 , pushing the ramp  140  up per the arrow  172  in  FIG. 3B  as the guide ramp  140  rotates about the pivot point  302 . To switch the guide ramp  140  from the extended position of  FIG. 3B  to the recessed position of  FIG. 3A , the control  138  is pulled out, as indicated by arrow  306  in  FIG. 3A . The control  138  no longer engages the guide ramp  140 , permitting the ramp  140  to freely rotate about the pivot point  302  to move downward per arrow  308  in  FIG. 3A . 
       FIGS. 4A, 4B, and 4C  show an example of the control  138  and the media sheet edge guides  142  in detail. As noted above, the edge guides  142  assist lateral positioning of the media sheet  128  during manual media sheet insertion, permitting accurate media sheet insertion between the guides  142 .  FIG. 4A  shows the edge guides  142  in the unused, recessed position.  FIG. 4B  shows the edge guides  142  in the used, extended position. Each media sheet edge guide  142  includes a pivot point  404 , and the control  138  includes a cam  402  matching the pivot point  404 . 
     To switch the media sheet edge guides  142  from the recessed position of  FIG. 4A  to the extended position of  FIG. 4B , the control  138  is pushed in, as indicated by the arrow  314  in  FIG. 4B . The cam  402  of the control  138  engages the edge guides  142  at their pivot points  404 , rotating the guides  142  upwards about the pivot points  404  per the arrow  174  in  FIG. 4B . The cam  402  and the pivot points  404  are configured so that the edge guides  142  can be individually pushed down back to the recessed position while the control  138  remains pushed in. 
     Pulling out the control  138 , as indicated by arrow  408  in  FIG. 4A , also switches the edge guides  142  from the extended position of  FIG. 4B  to the recessed position of  FIG. 4A . As the cam  402  releases the edge guides  142 , the cam  402  causes the guides  142  to rotate downwards about their pivot points  404  per the arrow  410  in  FIG. 4A . Whereas the edge guides  142  can be individually pushed back to the recessed position while the control  138  remains pushed in as in  FIG. 4B , pulling out the control  138  switches every guide  142  in the extended position to the recessed position of  FIG. 4A . 
       FIG. 4C  shows a view of the control  138  and the media edge guides  142  along the output tray  104 , in the used, extended position, looking inwards in the direction of the arrow  304  of  FIG. 4B . In the example of  FIG. 4C , there are two pairs of edge guides  142 : an inner edge guide pair and an outer edge guide pair. The space between each pair of edge guides  142  corresponds to a different media size. Because the edge guides  142  can be individually pushed down to their recessed position while the control  138  remains pushed in, the inner guide pair can be pushed down when inserting a media sheet having a size corresponding to the outer guide pair. The inner guide pair can be smaller in height than the outer guide pair, as shown in  FIG. 4C , so that when inserting a media sheet having a size corresponding to the outer guide pair, the sheet rests on the inner pair while still being able to be guided by the outer pair. 
       FIG. 5  shows an example method  500  for printing using a printing device having a duplex printing path with a duplex reversal point at which a media sheet can be manually inserted into the printing device. The method  500  can be performed by a printing device controlling a print engine, rollers, and other components of the device. The method  500  may be implemented as code stored on a non-transitory computer-readable data storage medium and executable by the printing device. 
     The controller determines the printing mode of the printing device ( 502 ). The printing device may operate in a simplex mode, a duplex mode, or a manual insertion mode. The user may specify the simplex mode or the duplex mode at the printing device or at a host computing device, such as a computer, to which the printing device is communicatively connected. The user may specify the manual insertion mode by pushing in a control as has been described, which the controller may detect and that correspondingly causes the controller the printing device to operate in the manual insertion mode. 
     If the printing mode is the simplex mode or the duplex mode ( 504 ), then the controller controls the rollers of the printing device to pick a media sheet from an input tray of the device ( 506 ). The controller causes the rollers to advance the media sheet through a simplex printing path of the device ( 508 ), beginning at a simplex entry point of the simplex printing path. As the media sheet advances along the simplex printing path, the controller causes a print engine of the printing device to print on a side of the sheet ( 510 ). 
     If the printing mode is the simplex mode ( 512 ), then the controller causes the rollers to output the simplex-printed media sheet on an output tray of the printing device ( 514 ). However, if the printing mode is the duplex mode ( 512 ), then the controller causes the rollers to reversibly draw the media sheet back in at a duplex reversal point ( 516 ). The controller causes the rollers to advance the media sheet through a duplex printing path of the printing device ( 518 ). 
     As the media sheet advances along the duplex printing path, the controller causes the print engine to print on the media sheet ( 520 ). The engine prints on the side of the sheet facing down when it was reversibly drawn in at the duplex reversal point. In the duplex mode, this is the side opposite the side that the engine printed on while the media sheet previously had advanced along the simplex printing path. The controller finally causes the rollers to output the duplex-printed media sheet on the output tray ( 514 ). 
     If the printing mode is the manual insertion mode ( 504 ), then the controller receives manual insertion of a media sheet at the duplex reversal point of the duplex printing path ( 522 ). As in the duplex mode, the controller causes the rollers to advance the media sheet through the duplex printing path ( 518 ), and causes the print engine to print on the sheet as it advances along the duplex printing path ( 520 ). The controller finally causes the rollers to output the media sheet on the output tray ( 514 ). 
       FIG. 6  shows an example non-transitory computer-readable data storage medium  600 . The computer-readable data storage medium  600  stores code  602  executable by a printing device. The printing device executes the code  602  to receive manual insertion of a media sheet at a duplex reversal point of a duplex printing path of the printing device ( 604 ), and advance the manually inserted media sheet through the duplex printing path ( 606 ). The printing device executes the code  602  to print on the media sheet as the sheet advances through the duplex printing path ( 608 ), and output the printed sheet from the printing device ( 610 ). 
       FIG. 7  shows an example printing device  700 . The printing device  700  includes a print engine  702 , rollers  704 , and a controller  706 . The rollers  704  define a duplex printing path having a duplex reversal point. 
     The controller  706  is implemented at least in hardware. For example, the controller  706  may be or include an application-specific integrated circuit (ASIC), which is a type of special-purpose processor programmed in accordance with program code, such that the ASIC constitutes both the processor and the data storage medium. The controller  706  may be or include a general-purpose processor that executes program code stored on a separate data storage medium like a semiconductor integrated circuit (IC) or a magnetic storage medium. 
     The controller  706  controls the rollers  704  to receive a media sheet manually inserted at the duplex reversal point ( 708 ). The controller  706  controls the rollers  704  to advance the manually inserted media sheet through the duplex printing path ( 710 ). The controller  706  controls the print engine  702  to print on the media sheet as the sheet advances through the duplex printing path ( 712 ). 
     Techniques have been described herein for leveraging a duplex printing path of a printing device having automatic duplex printing capability to also receive manual insertion of media sheets at a duplex reversal point of the duplex printing path. A media sheet having a different type, including a different size, than the media sheets loaded in an input tray of the printing device can be more easily loaded into the device for printing. The media sheets in the input tray do not have to be disturbed, nor does the printing device have to include an additional input tray.