Patent Publication Number: US-7220070-B2

Title: Printer having a continuous paper holder

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   The present application is a continuation of PCT/JP04/03171, filed Mar. 11, 2004 and claims benefit of priority from the prior Japanese Patent Application No. 2003-088805 filed on Mar. 27, 2003. 

   TECHNICAL FIELD 
   The present invention relates to a printer which records images on paper. 
   BACKGROUND OF THE INVENTION 
   An inkjet printer discharges ink drops using piezoelectric elements, thermal elements, or electrostatic actuators, for example, so that the discharged ink drops form images on paper. A continuous paper holder or automatic sheet feeder (ASF) is also typically attached to the inkjet printer, and the printer conveys roll paper supplied from the continuous paper holder or individual sheets supplied from the automatic sheet feeder in a specific direction and records images on the supplied paper while controlling paper transportation and ink drop discharge. 
   An inkjet printer of this general type supplies paper from a paper supply opening rendered at the back of the printer case (housing) to the paper transportation path, discharges ink drops from an ink head disposed to a carriage onto the paper conveyed to a specific position in the paper transportation path to record an image, and then discharges the paper from a paper exit rendered at the front of the housing. This inkjet printer is covered in the directions through the thickness of the paper and the width of the paper by the housing and covers, thus protecting the image recording members and other internal components. See, for example, Japanese Unexamined Patent Appl. Pub. H11-348364 (FIG. 1) in which an inkjet printer is taught in which the maximum printable paper size is limited by the size of the paper supply opening. Printing an image on paper that is larger than a specific size, and particularly paper that is wider than a specific size, is therefore not possible. 
   Furthermore, with the inkjet printer taught in Japanese Unexamined Patent Appl. Pub. H11-348364 the paper on which images are recorded is conveyed from the paper supply opening along the paper transportation path inside the inkjet printer, and even the shape of the conveyable paper is thus also limited. As a result, printing for special purposes, such as conveying note paper that has a relatively complex shape compared with single sheet paper or roll paper and printing images on a particular page of bound notebook paper, is thus not simple. 
   SUMMARY OF THE INVENTION 
   In view of the foregoing problem, an object of the present invention is to provide a printer having no limitation on the size or shape of the printable paper. 
   The printer of the present invention comprises: 
   a main printer unit having an image recording unit for printing on paper, 
   a base unit which is disposed opposite said image recording unit for supporting said image recording unit; 
   a paper transportation path disposed between said image recording unit and said base unit; and
         paper feed means for directing paper along said paper transportation path in a given paper transportation direction,       

   wherein said printer has opposite sides and a common opening extending from each opposite side in relative alignment to the paper transportation direction for manually inserting paper of substantially any size into said paper transportation path from any of the opposite sides of said printer 
   The printer is preferably fixed cantilevered at one end portion of the base unit. 
   The printer may also comprise: 
   a continuous paper holder which is removably attached to the main printer unit for supplying paper continuously to the paper transportation path; or 
   a sheet feeder device which is removably attached to the main printer unit for sequentially supplying a plurality of sheets of paper to the paper transportation path when said continuous paper holder is not supplying paper. 
   The continuous paper holder includes a projection which obstructs inserting paper to the paper transportation path through the opening when the continuous paper holder is installed to the main printer unit. 
   The continuous paper holder comprises a base unit receiving portion for holding the base unit; and 
   a continuous paper holding portion formed in unison with the base unit receiving portion for holding a supply of paper for said continuous paper holder to continuously supply paper to the paper transportation path. 
   The continuous paper holding portion holds the continuous paper wound in a roll so that the maximum height of the continuous paper is less than or equal to the height of the paper transportation path. 
   The sheet feeder device allows inserting paper to the paper transportation path from a direction substantially perpendicular to the paper transportation direction when the sheet feeder device is installed to the main printer unit. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is an oblique view from the front of the main printer unit of an inkjet printer according to a preferred embodiment of the invention. 
       FIG. 2  is an oblique view from the back of the main printer unit. 
       FIG. 3  is a section view through line III—III in  FIG. 2 . 
       FIG. 4  is an oblique view showing the arrangement in the proximity of the paper transportation path. 
       FIG. 5  is a section view showing the paper transportation path when the parts constituting the bottom surface of the paper transportation path are lowered. 
       FIG. 6  is an oblique view from the front showing how the roll paper holder is attached to the main printer unit. 
       FIG. 7  is an oblique view from the back showing how the roll paper holder is attached to the main printer unit. 
       FIG. 8  is a section view showing the roll paper holder attached to the main printer unit. 
       FIG. 9  is an oblique view showing an ASF which can be attached to the main printer unit. 
       FIG. 10  shows the ASF attached to the main printer unit. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION 
   An embodiment of an inkjet printer is described below with reference to the accompanying figures as a preferred embodiment of a printer according to the present invention. 
   An inkjet printer according to this embodiment of the invention has a main printer unit  1  (shown in  FIG. 1  to  FIG. 5 ), a continuous paper holder  40  (referred to as a “roll paper holder”) (see  FIG. 6  to  FIG. 8 ) and a slip supply apparatus  60  (or automatic supply feeder “ASF”) (see  FIG. 9  and  FIG. 10 ) which are removably attached to the main printer unit  1 . The parts of this inkjet printer are described below. 
   (External Construction of the Main Printer Unit) 
     FIG. 1  is an oblique view from the front of the main printer unit  1  of an inkjet printer according to a preferred embodiment of the invention, and  FIG. 2  is an oblique view of the main printer unit  1  as seen from the back. 
   The general external arrangement of the main printer unit  1  in this embodiment of the invention has an image recording unit  3  supported in a cantilevered manner at one end of the base unit  2  by way of an intervening cantilever unit  4 . A paper transportation path  5  for conveying paper from the back side to the front side is rendered between the base unit  2  and image recording unit  3 . 
   The paper transportation path  5  has a front opening  5   a , a back opening  5   b , and a contiguous side opening  5   c . Paper inserted to the paper transportation path  5  is preferably conveyed in the direction from the back opening  5   b  side to the front opening  5   a  side. In a main printer unit  1  according to this embodiment of the invention paper can be inserted to the paper transportation path  5  from any one of these openings, that is, the front opening  5   a , back opening  5   b , or side opening  5   c.    
   More specifically, paper can be inserted to the paper transportation path in the main printer unit  1  of the present embodiment not only from the back but also from the front and side. More particularly, paper can be manually inserted to the paper transportation path  5  of the main printer unit  1  for printing from a direction substantially perpendicular to the paper transportation direction through the side opening  5   c . In other words, the main printer unit  1  is arranged so that paper can be inserted through the side opening  5   c  to the paper transportation path  5  from a direction parallel to the paper transportation surface that functions as the paper transportation path  5  between the base unit  2  and image recording unit  3 . 
   The outside walls of the base unit  2 , image recording unit  3 , and cantilever unit  4  are formed by a front case  11  and a back case  12 . The front case  11  is composed of a base unit front case  2   a , cantilever unit front case  4   a , and image recording unit front case  3   a  integrally formed in a roughly U-shaped arrangement. The back case  12  is composed of a base unit back case  2   b , cantilever unit back case  4   b , and an image recording unit back case  3   b  integrally formed in a roughly U-shaped arrangement. As shown in  FIG. 1 , an opening  13  composed of mutually opposing U-shaped cut-out  11   a  and cut-out  12   a  is formed in the top of image recording unit front case  3   a  and image recording unit back case  3   b.    
   A cover  14  is openably and closably attached via a hinge  14   a  to the edge portion of cut-out  12   a  in the image recording unit back case  3   b . This cover  14  is attached in order to cover the opening  13  when closed as shown in  FIG. 2 . By thus covering the opening  13 , the cover  14  protects the internal components (not shown in  FIG. 1 ) of the image recording unit  3  from the outside of the main printer unit  1 . A protruding tab  14   b  for opening and closing the cover is disposed to the cover  14  on the edge on the opposite side as the side on which the hinge  14   a  is formed. This protruding tab  14   b  is formed so that the user can easily catch the tab  14   b  with a finger to open the cover  14 . The user can access the internal components of the image recording unit  3  for maintenance when the cover  14  is open as shown in  FIG. 1  so that, for example, an ink cartridge removably installed to the carriage  25  described below can be replaced. 
   A release lever  15  is further disposed to the cantilever unit back case  4   b . This release lever  15  is rendered so that the release lever  15  can be pushed down and the platen  21  (see  FIG. 3 ) forming part of the paper transportation path  5  as described below moves up and down in conjunction with other parts attached to the platen  21  when the release lever  15  is operated so that paper can be inserted to the paper transportation path  5 . Operation of the release lever  15  is described in further detail below. 
   A power cable connector  16  to which a cable connected to an external power source is connected to supply power for driving the printer, a data communication terminal  17  to which is connected a USB cable, for example, for data communication between the printer and a personal computer or other host computer, and an ASF drive cable connector  18  to which is connected a power cable for supplying power to the ASF (automatic sheet feeder)  60  are disposed to a portion of the base unit back case  2   b  below the cantilever unit  4 . 
   A cable connection confirmation pin (not shown in the figure) for confirming whether a cable for supplying power to the ASF  60  is connected is also disposed to the ASF drive cable connector  18 . The main printer unit  1  determines whether the ASF  60  described below is connected from the cable connection confirmation pin, which is shorted when a cable is connected to the ASF drive cable connector  18 . The ASF drive cable connector  18  thus also functions as an ASF connection sensor for determining whether the ASF  60  is installed. 
   As also shown in  FIG. 2 , slots  19   a  for attaching the ASF  60  are formed on the back of the image recording unit back case  3   b . In addition, slots  19   b  for attaching the roll paper holder  40  described below are formed in the back of the base unit back case  2   b . Attaching the roll paper holder  40  and the ASF unit  60  to the printer is described further below. 
   (Internal Structure of the Main Printer Unit) 
     FIG. 3  is a section view through line III—III in  FIG. 2  showing the major components of the internal structure of the main printer unit  1 .  FIG. 4  is an oblique view showing the arrangement around the paper transportation path, and  FIG. 5  is a section view showing the parts constituting the bottom surface of the paper transportation path in the lowered position. 
   A platen  21  constitutes the major part of the bottom surface of the paper transportation path  5  from the back opening  5   b  to the front opening  5   a . The platen  21  is a plate-like member forming the top surface of the base unit  2 , and the top surface  21   a  thereof is substantially flat as shown in  FIG. 4 . Disposed to the top of the paper transportation path  5  opposite the platen  21  in order from the upstream side are a paper guide  22 , main paper transportation roller  23 , carriage  25 , automatic paper cutter  29 , and TOF lever  33 . A control circuit board  35  is located below the platen  21 . These components are further described below as they relate to the platen  21 . 
   The paper guide  22  is disposed opposite the platen  21  on the upstream side of the paper transportation path  5 . The paper guide  22  forms a convexly curving surface on the side facing the paper transportation path  5  so that paper supplied from the back opening  5   b  is inserted smoothly to the paper transportation path  5 . Paper inserted from the back opening  5   b  is conveyed between the platen  21  and paper guide  22  to the main paper transportation roller  23 . 
   Multiple recessed portions  21   b  are formed at approximately the middle of the platen  21  in the paper transportation direction. A paper feed roller  24  is rotatably disposed in each of these recessed portions  21   b . The paper feed rollers  24  are located opposite the main paper transportation roller  23  located thereabove, and thus follow rotation of the main paper transportation roller  23 , which is driven by a motor not shown. The paper is nipped between the main paper transportation roller  23  and paper feed rollers  24 , and can thus be conveyed in the paper transportation direction or the opposite direction. 
   A BOF lever  27  is disposed to the platen  21  near the main paper transportation roller  23 . This BOF lever  27  is a part of the paper trailing-end detector, and is arranged so that conveying paper over the platen pushes the BOF lever  27  down. This depression of the BOF lever  27  is sensed by a BOF sensor not shown which is composed of an optical sensor and linkage mechanism formed integrally to the BOF lever  27 , for example. This optical sensor not shown detects a state change in the BOF lever  27  and outputs a signal to the control circuit board  35 . As a result, the paper is known to be below the BOF lever  27 . This BOF sensor also senses the timing at which the BOF lever  27  returns to the previous state, and outputs a signal to the control circuit board  35 . That the paper has moved from above the BOF lever  27  can thus be determined. 
   The carriage  25  is disposed opposite the platen  21  on the downstream side of the main paper transportation roller  23 . The carriage  25  is supported by a guide plate  28  and guide shaft  26  extending lengthwise along the direction (perpendicular to the paper transportation path  5 , that is, widthwise to the paper) joining the paper transportation path  5  side  4   c  of the cantilever unit  4  and the side opening  5   c . The carriage  25  can thus slide freely along the guide shaft  26  and guide plate  28  perpendicularly to the paper transportation path  5 . 
   The carriage  25  carries an inkjet head (not shown in the figure) having a plurality of nozzles for discharging ink to the paper disposed facing the platen  21 . Images are recorded on paper positioned on the platen  21  by discharging ink from plural nozzles of the ink head while the carriage  25  travels along the guide shaft  26 . An ink cartridge (not shown in the figure) for supplying ink to the ink head is also removably installed to the carriage  25 . 
   An automatic paper cutter  29  is disposed on the downstream side of the carriage  25 . The automatic paper cutter  29  is composed of a cutter guide  29   a  which is slidably fixed on the image recording unit  3  side, and a disk-shaped rotating cutter blade  31  rotatably axially supported by a rotating shaft  30  on the cutter guide  29   a  between the cutter guide  29   a  and guide plate  28 . The rotating cutter blade  31  is located opposite a stationary cutter blade  32  disposed to the platen  21 . The automatic paper cutter  29  cuts roll paper positioned over the stationary cutter blade  32  by pressing and moving the rotating cutter blade  31  against the stationary cutter blade  32  widthwise to the paper in conjunction with the cutter guide  29   a.    
   Paper transportation subrollers  34  are located near the front opening  5   a  on the downstream side of the automatic paper cutter  29 . The paper transportation subrollers  34  are rotatably axially supported on the platen  21  by means of rotary shaft  34   a . The paper transportation subrollers  34  are opposite a paper transportation subroller guide not shown, and thus convey paper in the paper transportation direction or the opposite direction with the paper nipped between the paper transportation subrollers  34  and this paper transportation subroller guide. The paper conveyed in the paper transportation direction by the paper transportation subrollers  34  is discharged from the front opening  5   a.    
   The TOF lever  33  is disposed to the paper transportation subroller guide not shown. This TOF lever  33  is a part of a paper leading-edge detector, and is disposed so that paper passing below the TOF lever  33  pushes the TOF lever  33  up. This raising of the TOF lever  33  is sensed by a TOF sensor not shown which is composed of an optical sensor and linkage mechanism formed integrally to the TOF lever  33 , for example. This optical sensor not shown detects a state change in the TOF lever  33  and outputs a signal to the control circuit board  35 . As a result, the paper is known to be above the TOF lever  33 . This TOF sensor also senses the timing at which the TOF lever  33  returns to the previous state, and outputs a signal to the control circuit board  35 . That the paper has moved from below the TOF lever  33  can thus be determined. 
   The control circuit board  35  disposed below the platen  21  is populated with a control chip for centrally controlling the operation of other parts of the main printer unit  1 , and memory chips for temporarily storing print commands and print data received through the command data communication terminal  17  from an external source. Detection signals from the TOF sensor, BOF sensor, ASF connection sensor, and a roll paper holder connection sensor  38  described below are sent to the control circuit board  35  for determining the position of the paper and whether the ASF  60  and roll paper holder  40  are installed. 
   When the release lever  15  is pushed down to the open position, the platen  21  and the parts attached to the platen  21  are also displaced downward as shown in  FIG. 5 . Displacing the platen  21  downward vertically opens the paper transportation path  5  so that slips can be manually inserted or roll paper can be loaded. The platen  21  returns to the position shown in  FIG. 3  when the release lever  15  is returned to the original closed position, thus preventing manual insertion of slips and inserting roll paper. 
   As described above, printing to manually inserted paper is possible using only the main printer unit  1 . When printing to manually inserted forms, the user can insert paper to the paper transportation path  5  inside the main printer unit  1  from any of the front opening  5   a , back opening  5   b , and side opening  5   c  to print images without worrying about the paper size. 
   More particularly, when using the main printer unit  1  alone, images can be printed with no concern for the shape of the part of the paper that is not inserted into the paper transportation path  5 . This enables inserting only one of multiple pages bound at one edge, such as in a book or notebook, to the paper transportation path  5  so that an image can be printed to just that one page. Specialized printing applications, such as printing an image on only one page or each page in a bound notebook, can thus be easily accomplished. 
   (Roll Paper Holder) 
     FIG. 6  is an oblique view showing installing a roll paper holder  40  to the main printer unit  1  as seen from the front,  FIG. 7  is an oblique view showing installing a roll paper holder  40  to the main printer unit  1  as seen from the back, and  FIG. 8  is a section view showing the roll paper holder  40  installed to the main printer unit  1 . 
   The roll paper holder  40  is configured for installation as a first attachment to the main printer unit  1  in this embodiment of the invention. The roll paper holder  40  and installation thereof are described next below. 
   The roll paper holder  40  is a part for supplying roll paper CS to the main printer unit  1  as continuous paper. The roll paper holder  40  is composed of main printer unit base  41  and a roll paper holding unit  45  attached in unison with the main printer unit base  41 . 
   The main printer unit base  41  is a base in which the base unit  2  of the main printer unit  1  fits, and is composed of a platform  41   a  which conforms to the shape of the bottom of the main printer unit  1  and is substantially rectangular when seen in plan view, four leg portions  42  formed in unison with the four corners of the platform  41   a , and side guide walls  41   b ,  41   c  rising vertically from the widthwise end portions of the platform  41   a . A portion of guide wall  41   b  curves from the widthwise end portion of the platform  41   a , and another portion of the guide wall  41   b  extends between the front edge and the back edge of the platform  41   a . The base unit  2  of the main printer unit  1  fits inside these guide walls  41   b ,  41   c  and is thus stationed on the platform  41   a . The bottom of the main printer unit  1  is thus raised by the main printer unit base  41  and the height of the paper transportation path  5  (the height from the installation surface) is thus higher than when the roll paper holder  40  is not installed. 
   Notch  41   d  is also formed in a portion of the guide wall  41   b  extending to the back-side edge of the platform  41   a  as shown in  FIG. 7  so that the power cable connector  16  and data communication terminal  17  disposed to the main printer unit  1  are not covered by the guide wall  41   b . A power supply cable and USB cable can thus be connected through this notch  41  to the power cable connector  16  and data communication terminal  17  while the main printer unit  1  is stationed on the main printer unit base  41 . Because the ASF  60  described below cannot be installed when the roll paper holder  40  is installed in this embodiment, the ASF drive cable connector  18  is covered by the guide wall  41   b.    
   Back guide wall  43  rises from the platform  41   a  at the back edge of the platform  41   a . Positioning ribs  44  corresponding to the slots  19   b  formed in the main printer unit  1  are disposed to the front of this back guide wall  43  as shown in  FIG. 6  and  FIG. 7 . These positioning ribs  44  fit into the slots  19   b  in the main printer unit  1  and thus position the main printer unit  1  on the platform  41   a . Note that  FIG. 7  is drawn to emphasize the installation parts for the roll paper holder  40 , and the roll paper holding unit  45  of the roll paper holder  40  is thus omitted from the figure. 
   A tab  44   a  is disposed to the vertical top end of one of the positioning ribs  44  (the left positioning rib  44  as seen in  FIG. 7 ). As shown in  FIG. 7  and  FIG. 8 , this tab  44   a  is inserted to the base unit back case  2   b  through an opening  19   c  formed at one lengthwise end of slot  19   b . A roll paper holder connection sensor  38  is installed at a position corresponding to this opening  19   c  inside the base unit back case  2   b.    
   This roll paper holder connection sensor  38  is composed of, for example, a sensor base  38   a  and a detection trigger  38   b  which is attached in order to move circularly to the sensor base  38   a . When the tab  44   a  of the positioning rib  44  is inserted to opening  19   c , the tab  44   a  contacts the detection trigger  38   b  and causes the detection trigger  38   b  to swing. The sensor base  38   a  detects this movement of the detection trigger  38   b  and outputs to the control circuit board  35 . The controller on the control circuit board  35  thus knows that the roll paper holder  40  was installed. 
   The roll paper holding unit  45  is attached to the back of the back guide wall  43 . The roll paper holding unit  45  is composed of guide members  46  and  47  which guide the widthwise sides of the roll paper CS, and a stationary spindle  49  which is fixed to the guide members  46  and  47  and allows the roll paper CS to turn. As shown in  FIG. 8  the stationary spindle  49  supports the roll paper CS by passing through a through-hole formed in the center of the take-up spool, and allows the roll paper to roll around the stationary spindle  49  as the leading end of the roll paper is pulled out. 
   As also shown in  FIG. 8  the roll paper holding unit  45  holds the roll paper CS so that when an unused roll of roll paper CS is loaded, the roll paper holding unit  45  holds the roll paper CS so that the maximum height H of the roll paper CS is substantially equal to or slightly below the height of the paper transportation path. 
   By thus holding the roll paper CS so that the maximum height H of the roll paper CS is substantially equal to or slightly below the height of the paper transportation path, the roll paper CS pulled out and conveyed through the paper transportation path  5  is not curled in the opposite direction as the curl of the wound roll when the paper enters the paper transportation path  5 . It is thus more difficult for problems such as the leading edge of the roll paper CS snagging or jamming inside the paper transportation path  5  inside the main printer unit  1  to occur when the roll paper is inserted, and the roll paper CS can be conveyed smoothly through the paper transportation path  5  when the paper is transported. 
   This is achieved by means of this arrangement whereby the main printer unit base  41  raises the bottom of the main printer unit  1  and positions the paper transportation path  5  at a greater height from the desk surface so that the stationary spindle  49  can be positioned at a low position even when the diameter of the roll paper CS is large. Conversely, because the height of the stationary spindle  49  can be set low, the maximum height H of the roll paper CS can be held at substantially the same height or slightly lower than the height of the paper transportation path even when the diameter of the roll paper CS is large. 
   Note that the roll paper CS is loaded in the main printer unit  1  by depressing the release lever  15  so that the paper transportation path  5  is open and then inserting the paper to the paper transportation path  5  from the back opening  5   b.    
   Manual insertion prevention tabs  50  and  51  are also formed as part of the guide members  46  and  47 . As shown in  FIG. 8 , these manual insertion prevention tabs  50  and  51  are rendered so that when the main printer unit  1  is stationed in the main printer unit base  41  of the roll paper holder  40  the manual insertion prevention tabs  50  and  51  intersect the plane extending the paper transportation path  5  of the main printer unit  1  in the paper transportation direction. When the roll paper holder  40  is installed to the main printer unit  1 , it is generally assumed that roll paper CS will be used for printing. Because roll paper CS will thus be loaded into the paper transportation path  5 , manually inserting paper from the side opening  5   c  is undesirable because a paper jam or other problem will result (of course, this is undesirable even if roll paper CS is not located in the paper transportation path  5 ). These manual insertion prevention tabs  50  and  51  are therefore disposed to the roll paper holder  40  in the present embodiment so that these manual insertion prevention tabs  50  and  51  interfere with inserting paper from the side opening  5   c  and thus prevent incorrect operation by the operator. 
   As described above, using roll paper holder  40  enables the main printer unit  1  to print images to roll paper CS. More specifically, printing on roll paper CS is enabled by simply attaching the roll paper holder  40  to the main printer unit  1  and loading roll paper CS in the paper transportation path  5 . 
   Furthermore, when the roll paper holder  40  is installed, supplying paper by manual insertion is structurally prohibited as described above. 
   (ASF (Automatic Sheet Feeder)) 
     FIG. 9  is an oblique view showing an ASF  60  for installation at the main printer unit  1 , and  FIG. 10  is a section view showing the ASF  60  installed at the main printer unit  1 . 
   A main printer unit  1  according to this embodiment of the invention is constructed so that an ASF  60  can be removably attached as a second attachment. The ASF  60  and installation thereof are described below. 
   The ASF  60  is a sheet feeding device that holds a plurality of slips of a particular size and supplies them one sheet at a time into the main printer unit  1 . The ASF  60  is primarily composed of a bottom case  61  and a top cover  70 . These parts are further described below. 
   The bottom case  61  is an integrally molded plastic box-like member having a front cover  62  and mutually opposing back cover  65  formed in unison with intervening side covers  63 ,  64 , and a bottom cover  66  rendered on the bottom formed in unison with the side covers  63 ,  64  and back cover  65 . An opening  60   a  is rendered at the top of the bottom case  61  between the front cover  62 , side covers  63 ,  64 , and back cover  65 . The top cover  70  is inserted from the opening  60   a  and fit to the bottom case  61  such that a portion of the opening  60   a  is covered. The uncovered portion of the opening  60   a  is the paper insertion opening from which a plurality of slips S are inserted at an angle. 
   A flat paper guide  68  which supports the part of the slips S located above the back cover  65  is attached to the top end of the back cover  65 . A paper size limiter  69  which limits the maximum size of slip paper that can be inserted from the opening  60   a  is also disposed at the top end of the back cover  65 . This paper size limiter  69  can slide along the top end of the back cover  65  and the position of the paper size limiter  69  can thus be appropriately adjusted to limit the paper size. By setting the width between the paper size limiter  69  and the side cover  61  to substantially the same as the width of the paper that is to be inserted, the paper can be guided by the side cover  61  and paper size limiter  69  and inserted without tipping sideways. 
   A slope  66   a  is disposed on top of the bottom cover  66  of the bottom case  61  so that the surface of the slope  66   a  is inclined towards the bottom cover  66  as shown in  FIG. 10 . Inserted slips are thus held by the back cover  65  and paper holding plate  68  in a stack in contact the slope  66   a  or bottom cover  66 . 
   Another opening  60   b  is rendered at the bottom of the bottom case  61  between the front cover  62 , side covers  63 ,  64 , and bottom cover  66 . This opening  60   b  forms a slip discharge opening from which slips inserted from the opening  60   a , which is the slip insertion opening, exit. 
   As shown in  FIG. 9 , L-shaped hooks  67  are disposed on the front edges of the side covers  63 ,  64 . These hooks  67  are rendered to match the slots  19   b  provided in the image recording unit back case  3   b  as shown in  FIG. 2 , and the ASF  60  is attached to the main printer unit  1  by engaging these hooks  67  in the slots  19   b .  FIG. 10  shows the ASF  60  installed to the main printer unit  1 . 
   A mounting rib  71  is formed in unison with the top cover  70  on the inside of the top cover  70  (the side facing the back cover  65 ), and a paper feed roller unit  72  is attached to this mounting rib  71 . This paper feed roller unit  72  has a gear  73  connected to a drive shaft  73   a  which is driven by a motor and cable not shown connected to the ASF drive cable connector  18 , gear  74  meshing with the gear  73 , gear  75  meshing with the gear  74 , gear  76  meshing with the gear  75 , gear  77  meshing with the gear  76 , and a supply roller  78  with a gear  78   a  meshing with the gear  77 . 
   When the drive shaft  73   a  of gear  73  is driven forward or in reverse, the paper feed roller unit  72  moves circularly closer to the slips or away from the slips, and is held either in a position with the supply roller  78  in contact with the paper or in a position with the supply roller  78  separated from the paper. When the drive shaft  73   a  rotates with the supply roller  78  touching the paper, gear  73  turns, the torque of gear  73  is transferred through the gears  74 ,  75 ,  76 ,  77  to gear  78   a , and the supply roller  78  disposed coaxially to gear  78   a  turns. 
   Rotationally driving the drive shaft  73   a  of the paper feed roller unit  72  to supply a slip to the main printer unit  1  causes the paper feed roller unit  72  to move circularly to the slips S and causes the supply roller  78  to contact the surface of the topmost slips S. Further rotationally driving the drive shaft  73   a  causes the supply roller  78  to rotate in the forward paper transportation direction (clockwise as seen in  FIG. 10 ), feeds the topmost slip S on the stack of plural slips S at a constant speed through the opening  60   b , and thus supplies the slip through the back opening  5   b  of the main printer unit  1  into the paper transportation path  5 . The main printer unit  1  then records an image on the supplied paper and discharges the paper from the front opening  5   a . If a next page is to be printed, paper is again fed from the ASF  60  into the paper transportation path  5  and an image is printed. 
   As shown in  FIG. 10 , when the ASF  60  is installed to the main printer unit  1 , the bottom cover  66  is positioned near an extension of the paper transportation path  5 . Because the back opening  5   b  is not closed by the ASF  60  when thus installed, paper can be manually supplied from the side opening  5   c  to the paper transportation path when the ASF  60  is installed. 
   As will be easily understood by comparison with  FIG. 8 , if the user attempts to install the ASF  60  to the main printer unit  1  while the roll paper holder  40  is installed to the main printer unit  1 , the manual insertion prevention tabs  50  and  51  of the roll paper holder  40  will contact the bottom cover  66  of the ASF  60  and thus obstruct installing the ASF  60 . As a result, the ASF  60  cannot be installed to the main printer unit  1  if the roll paper holder  40  is also installed. 
   Likewise, if the user attempts to install the roll paper holder  40  to the main printer unit  1  while the ASF  60  is installed, the manual insertion prevention tabs  50  and  51  of the roll paper holder  40  will contact the bottom cover  66  of the ASF  60  and thus obstruct installing the roll paper holder  40 . The roll paper holder  40  thus cannot be installed to the main printer unit  1  if the ASF  60  is installed. The arrangement of an inkjet printer according to this embodiment of the invention thus prohibits installing both the ASF  60  and roll paper holder  40  to the main printer unit  1  at the same time. 
   Installing the ASF  60  to the main printer unit  1  enables continuously supplying slips into the paper transportation path and enables printing images on the conveyed slips. Manual paper supply is also possible when the ASF  60  is installed. 
   An inkjet printer according to this embodiment of the invention as described above has a main printer unit  1  which has a image recording unit  3 , which has a carriage  25  on which an ink head for discharging ink to paper and a guide shaft  26  for slidably guiding the carriage  25 , and a base unit  2 , which is disposed opposite the image recording unit  3  and supports the image recording unit  3 . A paper transportation path  5  for conveying paper in the paper transportation direction is rendered between the image recording unit  3  and base unit  2 . A side opening  5   c  enabling inserting paper to the paper transportation path  5  from a direction substantially perpendicular to the paper transportation direction is also rendered between the image recording unit  3  and base unit  2 . More specifically, the side opening  5   c  is provided as by securing the image recording unit  3  cantilevered from one end of the base unit  2  on an intervening cantilever unit  4 . 
   An inkjet printer according to this embodiment of the invention thus easily enables manually supplying paper through the side opening  5   c  into the paper transportation path  5 . Furthermore, because paper can be supplied from the side (a direction substantially perpendicular to the paper transportation path), there is no limit to the size of paper and paper can be manually supplied to the paper transportation path  5  regardless of the shape of the paper. It is therefore possible to supply only one page of an already bound volume such as a book or notebook into the paper transportation path  5 , and special printing applications such as printing images on individual pages of a bound volume are possible. 
   An inkjet printer according to this embodiment of the invention also has a roll paper holder  40 , which is removably attached to the main printer unit  1  for supplying roll paper CS (continuous paper) as the print medium to the paper transportation path  5 , and an ASF  60 , which is removably attached to the main printer unit  1  for continuously supplying slips S as the print medium to the paper transportation path  5 . 
   Because the roll paper holder  40  and ASF  60  can thus be installed to and removed from the main printer unit  1 , the arrangement of the inkjet printer can be changed according to the printing application to enable printing to manually fed paper, slip printing, and roll paper printing. 
   Furthermore, in an inkjet printer according to this embodiment of the invention the roll paper holder  40  has manual insertion prevention tabs  50  and  51  which interfere with manual insertion of paper to the paper transportation path from a direction perpendicular to the paper transportation direction when the roll paper holder  40  is installed to the main printer unit  1 . 
   Therefore, because manually loading paper is not possible when the roll paper holder  40  is installed to the main printer unit  1 , unreasonable operations such as manually inserting paper to the paper transportation path  5  when roll paper is already in the paper transportation path  5  are prohibited, and problems such as improper operation of the printer and printer breakdowns are prevented. 
   The roll paper holder  40  of an inkjet printer according to this embodiment of the invention has a main printer unit base  41  for holding the base unit  2 , and a roll paper holding unit  45  formed in unison with the main printer unit base  41  for holding roll paper CS for supply to the paper transportation path  5 . More specifically, the bottom of the main printer unit  1  is held in an elevated position by the main printer unit base  41 . Therefore, even when the diameter of the roll paper CS is large, the leading end of the roll paper CS can be easily supplied into the paper transportation path  5 . 
   Furthermore, the roll paper holding unit  45  in an inkjet printer according to this embodiment of the invention holds the roll paper CS wound in a roll so that the maximum height H of the roll paper CS is at or below the elevation of the paper transportation path  5 . 
   Therefore, the roll paper CS pulled off the roll and conveyed into the paper transportation path  5  is not curled in the opposite direction as the direction of the curl imparted by the roll winding. The main printer unit  1  can thus smoothly convey the roll paper CS into the paper transportation path  5 . 
   Furthermore, an inkjet printer according to this embodiment of the invention allows inserting paper to the paper transportation path from a direction substantially perpendicular to the paper transportation direction when the ASF  60  is installed to the main printer unit  1 . 
   Paper can thus be manually supplied and manually inserted paper can be printed even when the ASF  60  is installed. 
   Yet further, the manual insertion prevention tabs  50  and  51  obstruct simultaneously installing both the roll paper holder  40  and ASF  60  to an inkjet printer according to this embodiment of the invention. 
   Problems such as a slip being supplied from the ASF  60  when roll paper CS is loaded in the paper transportation path  5  are thus prevented, and problems caused by improper operation are prevented. 
   The roll paper holder  40  is attached to the base unit  2  of the main printer unit  1  and the ASF  60  is attached to the image recording unit of the main printer unit  1  in an inkjet printer according to this embodiment of the invention, but the invention shall not be so limited and could be arranged so that the roll paper holder  40  is attached to the image recording unit  3  using slots  19   a , for example. 
   Furthermore, the manual insertion prevention tab  50  could be disposed projecting in front of the side opening  5   c  in order to obtrude the side opening  5   c . The guide wall  41   b  could also be shaped so that it extends and obtrudes the side opening  5   c . These variations structurally prohibit supplying paper manually. 
   The present invention has been described using an inkjet printer by way of example above, but a printer according to the present invention shall not be limited to an inkjet printer and the present invention can be applied to other types of printers, including thermal and dot impact printers. 
   INDUSTRIAL APPLICABILITY 
   A printer according to the present invention as described above has a main printer unit composed of an image recording unit for printing on paper and a base unit which supports the image recording unit. A paper transportation path is provided between the image recording unit and base unit for conveying paper in a paper transportation direction under the control of paper feed means, with the printer having a side opening for inserting paper to the paper transportation path. 
   A printer according to the present invention thus permits paper to be easily manually inserted into the paper transportation path from a common opening extending from each side of the printer. Furthermore, because paper can be supplied from any side (preferably perpendicularly to the paper transportation direction), there is no limit to the size of paper and paper can be manually supplied to the paper transportation path regardless of the shape of the paper. It is therefore possible to supply only one page of an already bound volume such as a book or notebook into the paper transportation path, and special printing applications such as printing images on individual pages of a bound volume are possible.