Patent Publication Number: US-7722151-B2

Title: Printing apparatus

Description:
BACKGROUND 
   Inkjet printers operate using a print head including a plurality of nozzles, which spray ink directly onto a print medium. Print head nozzles often become clogged with ink or particulates resulting in inefficient operation of the print heads and reduced print quality. Therefore, inkjet printers usually include a service station that provides functions for maintenance of the print heads. In order to provide this printer functionality, conventional printers employ multiple drive motors. This adds considerable expense and complexity to the printing device. Accordingly, the ever-increasing demand for printing devices, such as inkjet printers, to provide high quality printing while minimizing manufacturing costs motivates the need to look for an alternative solution to accomplish this printer functionality. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a high-level flowchart of a method in accordance with an embodiment. 
       FIG. 2  illustrates a drive transmission configuration in accordance with an embodiment. 
       FIG. 2(   a ) shows a view of a service station subsystem in accordance with an embodiment. 
       FIG. 2(   b ) shows an alternate view of the service station subsystem whereby additional elements are illustrated. 
       FIG. 3  illustrates a flowchart of the carriage lift operational state in accordance with an embodiment. 
       FIG. 3(   a ) shows a view of the service station subsystem in conjunction with the carriage lift operational state. 
       FIG. 4  illustrates a flowchart of the service station drive operational state in accordance with an embodiment. 
       FIG. 5  illustrates a flowchart of the service station drive operational state in accordance with an embodiment. 
       FIG. 5(   a ) shows a view of the service station subsystem in conjunction with the primer drive “priming” operational state. 
   

   DETAILED DESCRIPTION 
   As shown in the drawings for purposes of illustration, a printing apparatus and a method of use thereof is disclosed. In an embodiment, the printing apparatus includes a media delivery motor, a pallet, a carriage and a transmission operatively coupled to the media delivery motor, the transmission configured to power a servicing operation and lift a carriage whereby multiple power channels can be selected based on media delivery motor motion, carriage movement, and pallet position. Accordingly, the transmission takes rotational motion from a paper path motor and enables three independent power channels in a service station side of the printing apparatus. 
   For the purposes of this patent application, a power channel is a source of mechanical rotational motion, available indefinitely, in both clock-wise and counter clock-wise rotational directions. A power channel can be used (and or temporarily coupled) to drive a mechanical system (or transmission) that employs rotational motion, to provide an assortment of functions. In an embodiment, three power channels are employed to service pens, the lift carriage and drive a pen primer without the addition of a dedicated DC motor to the service station. The individual power channels are selected by a combination of feed shaft, carriage and pallet motions. Once engaged each power channel is independent of the other and both rotational directions are available for each power channel. 
     FIG. 1  is a high-level flowchart of a method in accordance with an embodiment. A first step  101  involves providing a movable carriage and a feed shaft mechanism operatively coupled thereto. A next step  102  involves employing the movable carriage and the feed shaft mechanism in order to provide at least two power channels to a printer apparatus. In an alternate embodiment, three independent power channels are provided. 
     FIG. 2  illustrates a drive transmission configuration in accordance with an embodiment.  FIG. 2  includes a media delivery motor  200 , a feed shaft mechanism  225  and a service station subsystem  250 . As can be seen in  FIG. 2 , the media delivery motor  200  is coupled to the service station subsystem  250  via the feed shaft mechanism  225 . 
   In an embodiment, the service station subsystem  250  includes a service station drive transmission and a primer transmission. For a better understanding, please refer now to  FIG. 2(   a ).  FIG. 2(   a ) shows a view of a service station subsystem  250  in accordance with an embodiment. Accordingly, the service station subsystem  250  includes a service station transmission  253 , a primer drive transmission  254 , a black channel  255 , a color channel  256 , a cap  257  and pallet  251 . 
     FIG. 2(   b ) shows an alternate view of the service station subsystem  250  whereby additional elements are illustrated.  FIG. 2(   b ) includes a shift arm  226 , a cam lift gear  228 , a spittoon  258 , a swing arm assembly  259 , a drive shaft  234  and a carriage lift arm  260 . 
   Accordingly, with a synchronized combination of movements between the media delivery motor  200 , the feed shaft mechanism  225  and the service station subsystem  250 , three states of operation are capable of being enabled: a carriage lift state, a service station drive state and a primer drive state. 
   Carriage Lift State 
   In order to enable this state of operation, the media delivery motor engages a forward feed and then the carriage moves to the home shift position. Home shift position is when the carriage reaches the far right side of the printer (as observed from the user&#39;s perspective). In this position, the swing arm assembly  259  has engaged either the carriage lift or pallet drive transmission, depending if the feed shaft direction was either forward or reverse prior to reaching the carriage stop location at home shift position. Forward feed is the direction of the feed shaft such that a piece of paper in the print mechanism would be ejected towards the user. Reverse feed is the opposite direction relative to forward feed. Here media would be reversed into the print mechanism and moved away from the user. Additionally, at home shift position, the carriage can also move off (in left direction) and continue printing or doing other functions. 
     FIG. 3  illustrates a flowchart of the carriage lift operational state. A first step  301  providing rotational power from a media delivery motor to a feed shaft in a forward direction. A second step  302  includes moving the carriage into the home shift position. A third step  303  involves determining if normal printer operations are to take place. If yes, step  304  involves performing a reverse feed until a hard stop is reached. A “Hard stop” refers to a designed position where mechanical parts interfere causing the DC servo to stop sending voltage to the driving motor. “Hard stops” are commonly used to safely go to known and repeatable mechanical positions in an electro mechanical device such as a printer. If no, step  305  involves employing forward feed rotational power to lift the carriage until it is fully raised. 
     FIG. 3(   a ) shows a view of the service station subsystem  250  in conjunction with the carriage lift operational state.  FIG. 3(   a ) illustrates the carriage  224  (not shown) and the pallet  251  whereby the carriage  224  and the pallet  251  are in the home shift position. In the carriage lift state of operation, normal printing and servicing operations can be performed as well as printing on a CD or other rigid media In order to print on a CD or other rigid media, forward feed rotational power is employed to lift the carriage until it is fully raised. A forward feed of feed shaft  225  aligns the swing arm assembly  259  to be ready to engage the cam lift gear  228 . With a carriage home shift position move, the carriage  224  applies a load to the shift arm  226  which in turn pivots about its axis. Since the shift arm  226  is coupled to the swing arm assembly  259 , this rotation about the shift arm axis causes the translation of the shift arm assembly  259  to the left direction. With this translation, a driving gear (not shown) mates with the cam lift gear  228  and rotates it in the clockwise direction (as seen from  FIG. 2   b ). Rotation of the cam lift gear  228  produces translation of the carriage lift arm  260  thus raising the carriage  224  upwards. 
   In order to perform normal printing and servicing operations, a forward feed and carriage home shift is performed, after which a reverse feed is performed until a hard stop is reached thereby returning the carnage to a lower (default) state. Normal printing operations refers to all actions performed in the print mechanism, which do not include carriage lift, pen servicing need or functions, or priming. Normal printing operations include picking of media, feeding of media in mechanism, firing ink onto page, etc. 
   Service Station Drive State 
   In order to enable this state of operation, the media delivery motor engages a reverse feed and the carriage is in the home shift position. In this operational state, wiping, spitting, wiper scraping, capping and all other general service takes place. For spitting, the carriage leaves the home shift position once the pallet is moved forward and interlocked. To uncap and return to printing, a reverse feed shaft move is made until the drive transmission releases from its interlocked state. This release occurs once the pallet is at the full back position and the pallet remains in this position until service moves or capping is needed. 
     FIG. 4  illustrates a flowchart of the service station drive operational state. A first step  401  providing rotational power from a media delivery motor to the feed shaft in a reverse direction. A second step  402  includes moving the carriage into the home shift position. A third step  403  includes determining if servicing operations are to take place. If no, step  404  involves maintaining the feed shaft position until the carriage is off from the home shift position and resuming printing. If yes, step  405  involves moving the pallet forward and interlocking the swing arm assembly with the pallet via the pallet interlocking rib. 
   In this embodiment, a reverse feed of feed shaft  225  aligns the swing arm assembly  259  to be read to engage the service station drive shaft  234 . With a carriage home shirt position move the carriage  224  applies a load to the shift arm  226  which in turn pivots about its axis. Since the shift arm  226  is coupled to the swing arm assembly  259 , this rotation about the shift arm axis causes the translation of the shift swing arm assembly  259  to the left direction. With this translation the driving gear (not shown) mates with the service station drive shaft  234  and rotates it in the counter-clockwise direction (as seen from  FIG. 2   b ). The service station drive shaft  234  mates with a rack (not shown) on the underside of the pallet  251  thus driving it forward with a counter-clockwise rotation. Once the driving gear (not shown) begins to drive the pallet  251 , it remains interlocked, and can drive the pallet  251  back and forth for general pen servicing or enter the primer drive state. 
   Primer Drive State 
   This operational state allows pen priming and tube purging operations to take place. As previously articulated, pen priming involves the removal of air that has migrated into the printing nozzles and purging involves removing stagnant waste ink that has accumulated inside the tubes. Engaging this state employs the same reverse feed shaft move and carriage home shift as employed by the service station drive state. The difference is that in the pallet “capped” position and pallet “purge” position, a carriage “left shift” is employed. Pallet capped position is defined as the position in which the forward position of the pallet has caused the rubber cap to translate up and create a seal around the orifice plate of the pen (not shown). Here, the pallet is in a position further forward relative to a user. Pallet purge position is similar to the pallet capped position, however in the purge position the seal between the cap and the orifice of the pen is broken thereby allowing air to escape. 
   A carriage “left shift” is accomplished when the carriage  224  engages a horn feature on cap  257  in the “capped” or “purge” positions. Once this feature on the cap  257  is engaged, the carriage  224  physically moves left approx 8 mm, pulling the  cap  257  with it. A carriage “left shift” disengages the driving of the pallet  251  and engages the driving of the primer. When the left shift occurs, rotational power is routed from the service station drive transmission to the primer drive transmission. In this operational state, reverse feed shaft rotational power allows for priming/purging of the color channel while forward feed shaft rotational power allows for priming/purging of the black channel. 
     FIG. 5  illustrates a flowchart of the primer drive operational state. A first step  501  determining if primer operations are to lake place. If no, step  502  involves driving the pallet as needed for pen servicing. Here, pen servicing involves all servicing other  than pen priming or tube purging. If yes, step  503  involves determining if a pen prime or pen purge is desired. 
   If a pen prime is desired, steps  504 - 508  are performed. Step  504  involves driving the pallet to a capped position. Step  505  includes moving the carriage into the left shift position. Here, the primer drive transmission is engaged and the pallet drive transmission is disengaged.  FIG. 5(   a ) shows a view of the service station subsystem  250  in conjunction with the primer drive operational state.  FIG. 5(   a ) shows the pallet  251  in the “capped” position and the carriage  224  in the left shift position. A next step  506  includes determining if the black channel or the color channel is to be primed. If the black channel is to be primed, step  507  involves moving the feed shaft forward and priming the black channel. If the color channel is to be primed, step  508  involves moving the feed shaft in a reverse direction and priming the color channel. 
   Going back to step  503 , if a pen purge is desired, steps  509 - 513  are performed. Step  509  involves driving the pallet to a purge position. Step  510  includes moving the carriage into the left shift position. Again, here the primer drive transmission is engaged and the pallet drive transmission is disengaged. A next step  511  includes determining if the black channel or the color channel is to be purged. If the black channel is to be purged, step  512  involves moving the feed shaft in a reverse direction and purging the black channel. If the color channel is to be purged, step  513  involves moving the feed shaft forward and purging the color channel. 
   Once the purge or prime is completed, in order to get out of this state of operation and back to the service station drive state, a carriage right shift is performed via step  514  whereby the primer drive transmission is disengaged and the pallet drive transmission is engaged. Consequently, the pallet is free to move for more servicing operations or printing operations. 
   A printing apparatus and a method of use thereof is disclosed. In an embodiment, the printing apparatus includes a media delivery motor and a transmission operatively coupled to the media delivery motor to provide rotational power from the motor to a service station subsystem. Accordingly, the transmission takes rotational motion from a paper path motor and enables three independent power channels in a service station side of the printing apparatus. 
   Without further analysis, the foregoing so fully reveals the gist of the present inventive concepts that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute the characteristics of the generic or specific aspects of this invention. Therefore, such applications should and are intended to be comprehended within the meaning and range of equivalents of the following claims. Although this invention has been described in terms of certain embodiments, other embodiments that are apparent to those of ordinary skill in the art are also within the scope of this invention, as defined in the claims that follow.