Patent Publication Number: US-7712412-B2

Title: Stencil printer with pressing member and moving device integrally movable out of printer body

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a stencil printer for printing an image on a sheet by pressing the sheet against a master wrapped round a print drum with pressing means and a stencil printer capable of printing images on both surfaces of a sheet in a single step. 
   2. Description of the Prior Art 
   A digital, thermosensitive stencil printer is known as a relatively simple, convenient printer and uses a stencil made up of a thermoplastic resin film and a porous support adhered together. In the stencil printer, while a thermal head, provided with a number of heat generating devices, is held in contact with the stencil, a platen roller or similar conveying means conveys the stencil. At this instant, current is selectively fed to the heat generating devices in the form of pulses in order to perforate, or cut, the thermoplastic resin film of the stencil with heat in accordance with image data, thereby producing a master. 
   After the master thus produced has been wrapped round a porous print drum, a sheet is pressed against the print drum via the master by a press roller or similar pressing means with the result that ink, applied to the inner periphery of the print drum, is transferred to the sheet via the porous portion of the print drum and perforations formed in the master, printing an image on the sheet. 
   Generally, in the stencil printer described above, the press roller is rotatably supported by a pair of arm members constantly biased toward the print drum by biasing means. The arm members are caused to angularly move by, e.g., cams rotatable in synchronism with the rotation of the print drum, selectively moving the press roller into or out of contact with the print drum. To prevent the sheet being conveyed toward or away from the press roller from getting under the press roller, it is a common practice to locate a guide plate, frame included in sheet conveying means or similar member in the vicinity of the press roller upstream or downstream of the press roller in the direction of sheet conveyance. 
   The problem with the above stencil printer is that because a space available around the press roller is limited, it is difficult to replace the press roller when the press roller is worn out due to repeated operation or to remove a sheet when the sheet gets under the press roller due to some cause and brings about a jam. 
   In light of the above, Japanese Patent Laid-Open Publication No. 64-16355, for example, proposes a stencil printer including a press roller rotatably, removably supported by a pair of press roller arms which are, in turn, angularly movably supported by the printer body. The press roller arms are mounted on a shaft in such a manner as to be movable in the axial direction of the shaft and unlockable from an arm stay affixed to the above shaft, so that the press roller can be removed from the printer body. 
   The current trend in the imaging art is toward a duplex printing system configured to print images on both surfaces of a single sheet for, e.g., saving sheets and spaces for the storage of documents. Japanese Patent Laid-Open Publication No. 2005-125716, for example, discloses an example of a stencil printer capable of producing a print carrying images on both surfaces thereof, i.e., a duplex print in a single step. The single step, duplex printing type of stencil printer taught in this document uses a divided master in which a first and a second image are formed side by side in the direction of rotation of a print drum, and is constructed to print one of the two images on one surface of a first sheet fed from a sheet feeding section, guide the sheet to an auxiliary tray, print the above image on one surface of a second sheet also fed from the sheet feeding section, guide the second sheet to the auxiliary tray while again feeding, or refeeding, the first sheet from the auxiliary tray, print the other image on the reverse surface of the first sheet, discharge the resulting duplex print, and repeat such a procedure thereafter. 
   However, the prior art stencil printers stated above have some problems left unsolved, as will be described hereinafter. 
   The stencil printer taught in Laid-Open Publication No. 64-16355 has a drawback that a space available around the press roller is too small to efficiently mount or dismount the press roller. This makes the replacement of the press roller or the removal of a jamming sheet troublesome. This is also true with the stencil printer of Laid-Open Publication No. 2005-125716. Another problem with Laid-Open Publication No. 2005-125716 is that a refeed tray adapted to temporarily store a sheet carrying an image on one surface thereof, i.e., a simplex print is configured to angularly move integrally with the press roller, making the removal of a sheet jamming the refeed tray difficult to perform. 
   Further, a modern stencil printer is constructed such that a print drum is removable from the printer body in order to implement, e.g., color printing. In this case, while the print drum is generally pulled out from the printer body to the front along, e.g., rail members and then removed from the printer body, no members should preferably exist below the print drum to allow the print drum to move downward when being removed from the printer body. Should the print drum with an uncovered surface contact any other member at the time of removal, the uncovered surface would be scratched or otherwise damaged and would render printing defective. 
   The stencil printer disclosed in Laid-Open Publication No. 2005-125716 mentioned earlier includes refeeding means for temporarily storing a simplex sheet come out of a printing section and again feeding it toward the printing section. When the simplex print thus existing on the refeeding means is caused to overlap the next sheet without being refed due to some cause and jams the refeeding means or when a jam occurs with the edge of a sheet being left on the refeeding means due to the short conveying force of the refereeing means, it is difficult to remove the jamming sheet because the space available for such work is extremely limited. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a stencil printer capable of allowing pressing means to be easily replaced or allowing a jamming sheet to be easily removed while protecting the surface of a print drum from damage during mounting or dismounting and a stencil printer implementing single step, duplex printing. 
   A stencil printer of the present invention includes a printer body, a print drum rotatably mounted on the printer body, a pressing member configured to press a sheet against the circumferential surface of the print drum, and a moving device configured to selectively move the pressing member into or out of contact with the outer circumference of the print drum. The pressing member and moving device are capable of being pulled out from the printer body integrally with each other. 
   Also, a stencil printer of the present invention operable in a duplex print mode for printing an image on one surface of a sheet and then printing an image on the reverse surface of the sheet includes a printer body. A printing section includes a print drum configured to wrap a divided master, which has a first image and a second image formed therein side by side in the direction of rotation of the print drum, round the print drum and pressing member selectively movable into or out of contact with the print drum. A sheet discharging section discharges the sheet undergone printing at the printing section. A refeeding device temporarily supports the sheet carrying the image on the one surface thereof and then refeeds it toward the printing section. A path selector steers the sheet passed through the printing section to either one of the refeeding device and a sheet discharging device. The printing section further includes a moving device configured to selectively move the pressing member into or out of contact with the print drum. The pressing member and moving device are capable of being pulled out of the printer body integrally with each other. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken with the accompanying drawings in which: 
       FIG. 1  is a front view showing the general construction of a first embodiment of the stencil printer in accordance with the present invention; 
       FIG. 2  is a view showing a mechanism supporting a press roller included in the first embodiment; 
       FIG. 3  is a view showing a support member also included in the first embodiment; 
       FIG. 4  is a front view showing the general construction of a second embodiment of the stencil printer in accordance with the present invention; 
       FIGS. 5 and 6  are views showing a mechanism supporting a press roller and refeeding means included in the second embodiment; 
       FIG. 7  is a front view showing the general construction of a third embodiment of the stencil printer in accordance with the present invention; 
       FIG. 8  is a side elevation showing a fourth embodiment of the stencil printer in accordance with the present invention; 
       FIG. 9  is a perspective view showing a discharge member included in the fourth embodiment; 
       FIG. 10  is a view showing a conventional movable guide; 
       FIG. 11  is a view showing a movable guide included in the fourth embodiment; 
       FIG. 12  is a side elevation showing the general construction of the stencil printer in accordance with the present invention; 
       FIG. 13  is a view showing locking means included in a fifth embodiment of the stencil printer in accordance with the present invention; and 
       FIG. 14  is a view showing a specific configuration of unlock switches included in the fifth embodiment. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIG. 1  of the drawings, a first embodiment of the stencil printer in accordance with the present invention is shown and generally designated by the reference numeral  1 . As shown, the stencil printer  1  includes a printing section  2 , a master making section  3  and a sheet discharging section  4 . 
   The printing section  2  is positioned at substantially the center of a printer body or casing  23 , see  FIG. 3 , and includes a print drum  5  configured to rotate clockwise, as viewed in  FIG. 1 , by being driven by print drum drive means not shown. A press roller or pressing means  6  is movable into or out of contact with the circumferential surface of the print drum  5  and configured to press, when in contact with the print drum  5 , a sheet fed from a sheet feeding section, not shown, against the print drum  5 . 
   The print drum  5  is generally made up of a porous support plate affixed at opposite edges thereof to the circumferential surfaces of a pair of end plates, not shown, and a mesh screen wrapped round the support plate in a plurality of layers. The porous support plate includes a porous portion formed with a plurality of through holes and a non-porous portion. A stage  7  is mounted on the non-porous portion of the support plate in a flat position along the axis of the print drum  5  while a clamper  8  is mounted on the stage  7  and supported by a shaft in such a manner as to be openable away from the stage. The clamper  8  is opened and closed when the print drum  5  is rotated to a preselected position not shown. 
   Ink feeding means  9  is arranged inside the print drum  5  and includes an ink feed pipe  10 , playing the role of a print drum shaft at the same time, an ink roller  11  and a doctor roller  12 . The ink feed pipe  10  extends between the opposite endplates mentioned above and supports a pair of end plates, not shown, such that the end plates are freely rotatable via respective bearings. An ink pump and an ink pack, not shown, are fluidly connected to the ink feed pipe  10  and configured such that when the ink pump is operated, ink in the ink pack is delivered to the inner periphery of the print drum  5  via a plurality of holes  10   a  formed in the pipe  10 . 
   The ink roller  11  is positioned between a pair of end plates, not shown, affixed to the ink feed pipe  10  and rotatably supported by the end plates. More specifically, the ink roller  11  is driven by drive means, not shown, to rotate in synchronism with and in the same direction as the print drum  5 . The circumferential surface of the ink roller  11  is spaced from the inner periphery of the print drum  5  by a small gap. 
   The doctor roller  12  is positioned in the vicinity of the ink roller  11  and rotatably supported by the same end plates as the ink roller  11  in such a manner as to be rotated in synchronism with, but in the opposite direction to the ink roller  11  by drive means not shown. The ink roller  11  and doctor roller  12  are spaced from each other by a small gap. A space with a generally wedge-shaped cross-section is formed at a position where the ink roller  11  and doctor roller  12  adjoin each other, forming an ink well  13 . 
   The ink fed from the holes of  10   a  of the ink feed pipe  10  is caused to drop into the above inkwell  13  and then deposited on the circumferential surface of the ink roller  11  in the form of a thin layer when passing through the portion where the ink roller  11  and doctor roller  12  adjoin each other. When the press roller  6  is moved into pressing contact with the print drum  5 , the ink roller  11  and the inner periphery of the print drum  5  are caused to contact each other with the result that the ink is fed to the inner periphery of the print drum  5 . 
   More specifically, the press roller  6  is positioned below the print drum  5 . As shown in  FIG. 2 , the press roller  6  is provided with substantially the same axial length as the print drum  5  and made up of a core  6   a  and a rubber or similar elastic body wrapped round the core  6   a . Axially opposite ends of the core  6   a  are positioned between a pair of generally L-shaped press rollers  14 , and each is rotatably supported by one end of the respective press roller arm  14 . Each press roller arm or flat plate-like member  14  is rotatably supported at its bent portion by a shaft  16  mounted on a support member  15 . 
   The support member  15  mentioned above is mounted on the printer body  23  such that it can be pulled out along rails or guide members  18  also mounted on the printer body  23  toward the front, as shown in  FIG. 3 . Usually, the support member  15  is locked to the printer body  23  by a locking device not shown. A cam follower  17  is rotatably mounted on the other end portion of each press roller arm  14 . 
   Two cams  19  are affixed to a cam shaft  19   a  in the vicinity of the cam follower  17  while the cam shaft  19   a  is rotatably supported by the support member  15 . A pin  19   b  is affixed to one end of the cam shaft  19   a  while being passed therethrough. When the support member  15  is mounted to the printer body  23 , a coupling  20 , positioned on the printer body  23 , is engaged with the pin  19   b . Torque output from the print drum drive means is transmitted to the coupling  20  so as to cause, when the pin  19   b  and coupling  20  are engaged with each other, the cams  19  to rotate in synchronism with the print drum  5 . 
   Tension springs  21  each are anchored at one end to the other end of associated one of the press roller arms  14  and at the other end to the support member  15 , constantly biasing the press roller arms  14  clockwise, as viewed in  FIG. 1 , about the shaft  16 . This allows the cam followers  17  to contact projections included in the respective cams  19 . In this configuration, when the projections of the cams  19  are brought into contact with the cam followers  17 , the press roller arms  14  are angularly moved counterclockwise, as viewed in  FIG. 1 , against the action of the tension springs  21 , moving the press roller  6  away from the print drum  5 . When the projections of the cams  19  are then brought out of contact with the cam followers  17 , the press roller arms  14  are angularly moved clockwise, as viewed in  FIG. 1 , under the action of the springs  21 , pressing the press roller  6  against the print drum  5 . At this instant, a preselected gap is formed between each cam  19  and the cam follower  17  associated therewith. 
   The press roller arms  14 , shaft  16 , cam followers  17 , cams  19 , cam shaft  19   a , pin  19   b , coupling  20  and tension springs  21  constitute moving means  22  for selectively moving the press roller  6  into or out of contact with the print drum  5 . The moving means  22  is operated to move the press roller  6  between a released position where the press roller  6  is released from the print drum  5 ,  FIG. 1 , and a contact position where the former is pressed against the latter by preselected pressure. 
   The master making section  3  is arranged at the upper left of the printing section  2  and includes stencil storing means  24 , a thermal head  25 , a platen roller  26 , master cutting means  27  and a roller pair  28  for conveyance. The stencil storing means  24  is adapted to support a stencil roll  29   a  such that the stencil roll  29   a  is freely rotatable and dismountable. 
   The thermal head  25 , including a number of heat generating devices, is supported by side walls, not shown, included in the master making section  3  and has a heat generating surface constantly pressed against the platen roller  26  by biasing means not shown. The platen roller  26  is rotatably supported by the side walls of the master making section  3  and rotated by a stepping motor not shown. 
   The master cutting means  27  includes a stationary edge affixed to the master making section  3  and a movable edge movable relative to the stationary edge. The movable edge is moved relative to the stationary edge by being rotated or moved in the up-and-down direction to thereby cut a stencil  29  at a preselected length and produce a master therefrom. The roller pair  28  is made up of a drive roller rotated by drive means, not shown, and a driven roller pressed against the drive roller so as to be rotated thereby. The drive roller and driven roller cooperate to convey the master made by the thermal head  25  and platen roller  26  toward the printing section  2 . 
   The sheet discharging section  4  is arranged below the master making section  3  and mainly constituted by a peeler  30 , a peel fan  31 , a sheet conveyor  32  and a print tray  33 . The peeler  30  is angularly movably supported by the side walls of the printer body at its base end and driven by peeler drive means, not shown, such that the end having an acute angle is selectively movable toward or away from the circumferential surface of the print drum  5 . The peel fan  31  is mounted on the printer body  23  and adapted to send air toward the position where the peeler  30  and print drum  5  adjoin each other. The peeler  30  and peel fan  31  cooperate to peel off a sheet carrying an image thereon, i.e., a print from the circumference of the print drum  5 . 
   The sheet conveyor  32  is positioned below the peeler  30  and provided with a conventional configuration including a drive roller, a driven roller, a plurality of parallel, endless belts formed with holes therein each and passed over the drive roller and driven roller, and a suction fan. The endless belts convey a sheet to the left, as viewed in  FIG. 1 , while the suction fan retains the sheet on the belts. 
   The print tray  33  is positioned at the left-hand side of the conveyer  32  and includes a single end fence  33   a  and a pair of side fences not shown. The end fence  33   a  is movable in the direction of sheet conveyance while the side fences are selectively movable toward or away from each other in the widthwise direction of a sheet, neatly positioning sheets, or prints, sequentially stacked on the print tray  33 . 
   The sheet feeding section mentioned earlier is located at the lower right of the printing section  2 , although not shown specifically, and adapted to feed sheets to the printing section  2  one by one. The sheet feeding section includes a sheet tray, a pickup roller, sheet separating means and a registration roller pair  34 . The pickup roller and sheet separating means are configured to pay out top one of a number of sheets stacked on the sheet tray while separating it from underlying sheets. The registration roller pair  34  is provided with a conventional configuration for stopping the sheet paid out from the print tray and then driving it toward the printing section  2  by being rotated at preselected timing such that the sheet meets an image formed in the master, which is also designated by the reference numeral  29 . 
   A master discharging section, not shown, is arranged at the upper right of the printing section  2  and adapted for peeling off a used master from the print drum  5  and discarding it. The master discharging section includes a discharge roller pair, waste master box and a compression plate. The discharge roller pair picks up the edge of a used master away from the surface of the print drum  5  and conveys it to the waste master box. Thereafter, the compression plate compresses the used master dropped into the waste master box. Such a configuration of the master discharging section is also conventional. 
   The stencil printer  1  in accordance with the illustrative embodiment will be operated, as follows. 
   The operator of the stencil printer  1  sets a desired document on an image scanning section, not shown, positioned on the top of the printer body  23  and then pushes a cut or perforation start key provided on a control panel not shown. In response, the document scanning section scans or reads the document while the master discharging section peels off a used master from the print drum  5 . Subsequently, the print drum  5  is rotated to a position where the clamper  8  is located substantially at the top and then stopped there. Thereafter, the clamper  8  is opened by opening/closing means not shown. In this condition, the stencil printer  1  awaits arrival of a master. This is followed by a master making operation. 
   The master making operation begins with causing the stepping motor and drive means to rotate the platen roller  26  and roller pair  28  for thereby paying out the stencil  29  from the stencil roll  29   a . The stencil  29  thus paid out is selectively perforated, or cut, by the heat generating devices of the thermal head  25  while being conveyed via the thermal head  25 , so that an image is formed in the stencil  29  in accordance with image data. The stencil  29  with the image is then conveyed by the platen roller  26  and roller pair  28  toward the clamper  8  held in the open position on the print drum  5 . 
   When the leading edge of the stencil  29  is brought to a preselected position between the stage  7  and the clamper  8 , as determined by control means, not shown, in terms of the number of steps of the stepping motor, the opening/closing means closes the clamper  8  in order to retain the leading edge of the stencil  29  on the print drum  5 . Subsequently, the print drum  5  is driven to rotate clockwise, as viewed in  FIG. 1 , at a peripheral speed identical with the stencil conveying speed, so that the stencil  29  is wrapped round the print drum  5 . When the stencil  29  is wrapped round the print drum  29  by a length corresponding to a single master, as also determined by the control means in terms of the number of steps of the stepping motor, the platen roller  26  and roller pair  28  are caused stop rotating while the cutting means  27  is driven to cut off the master  29  from the stencil  29 . Thereafter, the master  29  is pulled out from the master making section  3  by the print drum  5 , which is in rotation. As soon as the print drum  5  is again rotated to its home position, it is brought to a stop. This is the end of a master making and wrapping operation. 
   The master making and wrapping operation stated above is followed by a master adhering operation. More specifically, the print drum  5  is caused to start rotating at a low speed while a single sheet is fed from the sheet feeding section and nipped by the registration roller pair  34 . The registration roller pair  34  is again driven at a timing when the leading edge of an image formed in the master  29  reaches a position where it faces the press roller  6 . Just after the above timing, the larger diameter portions of the cams  19  move away from the cam followers  17  with the result that the press roller arms  14  are angularly moved under the action of the tension springs  21 , pressing the press roller or pressing member  6  against the outer periphery of the print drum  5  via the master  29 . As a result, the ink applied to the inner periphery of the print drum  5  by the ink roller  11  is transferred to the sheet via the porous portion of the print drum  5 , mesh screen and perforations formed in the master  29 , causing the master  29  to adhere to the print drum  5 . 
   The sheet with the ink transferred thereto, as stated above, is peeled off from the print drum  5  by the peeler  30  and peel fan  31 , dropped and then conveyed to the print tray  33  by the sheet conveyor  32 . In this condition, the stencil printer  1  remains in a stand-by state. 
   When the operator presses a trial print key, not shown, also provided on the control panel, the print drum  5  is rotated at a higher speed than during the master adhering operation while another sheet is fed from the sheet feeding section. This sheet, like the previous sheet, is pressed against the print drum  5  by the press roller  6 , peeled off from the print drum  5  and then driven out to the print tray  33  as a trial print. 
   The operator then checks the density, position and so forth of an image printed on the trial print, adjusts such factors on various keys arranged on the control panel, produces another trial print, sets a desired number of prints and a desired print speed, and then pushes a print start key on the control panel. In response, the print drum  5  is driven at a peripheral speed corresponding to the desired print speed while sheets are fed from the sheet feeding section one by one. As soon as the desired number of prints are produced, the print drum  5  is stopped at the home position. In this condition, the stencil printer  1  again remains in the stand-by state. 
   Assume that a jam occurs during the above master adhering, trial printing or actual printing operation, e.g., a sheet conveyed by the registration roller pair  34  gets under or wraps round the press roller  6 . Then, in response to information output from a sensor, not shown, the operation of the stencil printer  1  is stopped as soon as the print drum  5  is brought to a position where the clamper  8  is located substantially at the bottom. At this instant, the cams  19  are held in contact with the cam followers  17 , holding the press roller  6  in the released position. 
   Subsequently, the operator unlocks the support member  15  from the printer body  23  by operating a locking device, pulls out the support member  15  toward the operator along the guide members  18 , and then removes the jamming sheet. The operator then returns the support member  15  to a preselected position in the printer body  23  and again locks the former to the latter. Thereafter, if the printing operation has been interrupted halfway, remaining part of the printing operation is effected. If desired, the support member  15  may be automatically mounted to or dismounted from the printer body  23  by use of a lead screw or a motor by way of example. Also, the support member  15  may be provided with holding means for holding the press roller in the released position. 
   As stated above, in the illustrative embodiment, a sheet, jamming any position around the press roller  6 , can be removed after the support member  15  with the press roller  6  has been pulled out from the printer body  23  and therefore efficiently in a broad space outside of the printer body  23 . In addition, such a support member  15  noticeably improves the efficient replacement of the press roller  6  and the efficient replacement or adjustment of any other part mounted on the support member  15 . 
   Reference will be made to  FIG. 4  for describing a second embodiment of the stencil printer in accordance with the present invention configured to implement the single step, duplex printing stated earlier. Because the configuration of the second embodiment is related to the configuration of the duplex printer taught in Laid-Open Publication No. 2005-125716 discussed previously, the description of various sections will be simplified as far as possible. 
   A printing section  36 , positioned at substantially the center of a printer body or casing, not shown, includes a print drum  37 , a press roller or pressing means  38 , refeeding means  39  and a path selector  40 . The print drum  37 , like the print drum  5 , is generally made up of a porous support plate affixed at opposite edges thereof to the circumferential surfaces of a pair of end plates, not shown, and a mesh screen wrapped round the support plate in a plurality of layers. A stage  41  is positioned on the non-porous portion of the porous support plate while a clamper  42  is mounted on the stage  41  in such a manner as to be openable about a shaft away from the stage  41 . The clamper  42  is opened and closed by opening/closing means, not shown, when the print drum  37  is rotated to a preselected position. 
   Ink feeding means  43 , similar to the ink feeding means  9 , is arranged inside the print drum  37  and includes an ink feed pipe  44 , playing the role of a print drum shaft at the same time, an ink roller  45  and a doctor roller  46 . The doctor roller  46  is positioned in the vicinity of the ink roller  45 . The ink roller  45  and doctor roller  46  are spaced from each other by a small gap. A space with a generally wedge-shaped cross-section is formed at a position where the ink roller  45  and doctor roller  46  adjoin each other, forming an ink well  47 . The ink is fed from the ink well  47  to the inner periphery of the print drum  37  via the ink roller  45 . 
   The press roller or pressing member  38  is positioned below the print drum  37  and configured in the same manner as a press roller  21  taught in Laid-Open Publication No. 2005-125716. More specifically, as shown in  FIG. 5 , the press roller  38  whose surface is covered with fine grains of glass, ceramics or the like includes a shaft portion  38   a  rotatably supported at opposite ends thereof by one end of a pair of press roller arms  48 , which are configured in the same manner as the press roller arms  14 . The press roller  38  is caused to rotate by a drive motor, not shown, as taught in Laid-Open Publication No. 2005-125716. Each press roller arm or flat plate-like member  48  is rotatably supported at its bent portion by a shaft  50  mounted on a support member  49 . The support member  49  is mounted on the printer body such that it can be pulled out of the printer body along rails or similar guide members  51  and is usually locked to the printer body by a locking device, not shown. 
   Cam followers  52  each are rotatably mounted on the other end portion of the respective press roller arm  48 . Two cam groups  53  are affixed to a cam shaft  53   a , which is rotatably supported by the support member  49 , in the vicinity of the cam followers  52 . A pin  53   b  is passed through one end of the cam shaft  53   a . A coupling  54 , see  FIG. 5 , is mounted on the printer body and brought into engagement with the pin  53   b  when the support member  49  is mounted to the printer body. Torque output from print drum drive means, not shown, is transferred to the coupling  54 , so that the cam groups  53  are rotated in synchronism with the print drum  37  when the pin  54  and coupling  53   b  are engaged with each other. 
   Each cam group  53 , like print pressure range varying means  28  taught in Laid-Open Publication No. 2005-125716, includes a plurality of cam plates and is configured to selectively open or close the cam plates to vary the contact range thereof with the associated cam follower  52  and therefore the contact range of the press roller  38  with the print drum  37 . More specifically, the press roller  38  is selectively caused to contact the print drum  37  over a first range corresponding to the area of a first image formed in a divided master, which will be described later specifically, the area of a second range corresponding to the area of a second image or a third range corresponding to the total area of the first and second images. 
   Tension springs  65  each are anchored at one end to the respective press roller arm  48  and at the other end to the support member  49 , constantly biasing the press roller arms  48  clockwise, as viewed in  FIG. 4 , about the shaft  50 . This allows the cam followers  52  to selectively contact the projections of the cams constituting the cam groups  53 . When the projections of the cam plates are brought into contact with the cam followers  52 , the press roller arms  48  are angularly moved counterclockwise, as viewed in  FIG. 4 , against the action of the tension springs  65 , releasing the press roller  38  from the print drum  37 . When the above projections of the cam plates are brought out of contact with the cam followers  52 , the press roller arms  48  are angularly moved clockwise, as viewed in  FIG. 4 , under the action of the tension springs  65 , pressing the press roller  38  against the print drum  37 . A preselected gap is formed between the cam plates and the cam followers  52  when the pres roller  38  is pressed against the print drum  37 . 
   In the above configuration, the press roller arms  48 , shaft  50 , cam followers  52 , cam groups  53 , cam shaft  53   a , pin  53   b , coupling  54  and tension springs  65  constitute moving means  66  for moving the press roller  38  into or out of contact with the print drum  37 . Thus, the press roller  38  is movable between a released position where it is spaced from the print drum  37 , as shown in  FIG. 4 , and a contact position where the former is pressed against the latter by preselected pressure. 
   A roller guide plate  55  and refeed rollers  56 , similar to a roller guide plate  50  and refeed rollers  51  taught in Laid-Open Publication No. 2005-125716, are positioned between the press roller arms  48  in the vicinity of the press roller  38 . The roller guide plate  55  is fixed in place between the press roller arms  48  at a preselected distance from the press roller while the refeed rollers  56  are rotatably supported between the press roller arms  48  in pressing contact with the bottom portion of the press roller  38 . 
   A refeed conveyor  57  and a movable guide  58 , similar to a refeeding device  104  and a guide  81  taught in Laid-Open Publication No. 2005-125716, are located at the lower left of the press roller  38  in  FIG. 4 . 
   The refeed conveyor  57  is comprised of a drive roller  59 , a driven roller  60 , a plurality of parallel endless belts  61  passed over the drive roller  59  and driven roller  60  and a suction fan  62  and has its end at the driven roller  60  side angularly movably supported. The drive roller  59  includes a shaft  59   a  rotatably supported by the support member  49 . As shown in  FIG. 6 , a drive gear  63  is affixed to one end of the shaft  59   a  protruding from the support member  49 . The drive gear  63  is configured to mesh with a pinion  64   a  mounted on the output shaft of a drive motor  64 , which is mounted on the printer body, when the support member  49  is mounted to the printer body. In this condition, when the drive motor  64  is energized, it causes the refeed conveyor  57  to operate via the pinion  64   a  and drive gear  63 . 
   The movable guide  58  is supported by the printer body above the refeed conveyor  57  and driven by drive means, not shown, to move back and forth between a first position close to the circumference of the press roller  38  and a second position,  FIG. 4 , remote from the same. The movable guide  58  nips the leading edge of a sheet carrying an image on one surface, i.e., a simplex print when moved to the first position and then releases it when moved to the second position. 
   The roller guide plate  55 , refeed rollers  56 , refeed conveyor  57 , guide  58  and drive motor  64  constitute the refeeding means  39  adapted for feeding a simplex print coming out of the printing section  36  again to the printing section  36 . 
   The path selector  40  is positioned above the refeed conveyor  57  at the left-hand side of the press roller  38 , as viewed in  FIG. 4 , and angularly movably supported by the printer body at its base end. The path selector  40  is moved by a solenoid, motor or similar actuator such that its edge having an acute angle is selectively positioned at a first position, indicated by a solid like in  FIG. 4 , where the edge is remote from the print drum  37  or a second position, indicated by a phantom line in  FIG. 4 , where the former is close to the latter. The path selector  40  steers, in the first position, a sheet coming out of the printing section  36  toward a sheet discharging section  74 , which will be described specifically later, or steers it, in the second position, toward the refeed conveyor  57 . 
   A master making section  67  is arranged at the upper left of the print drum  37  and includes stencil storing means  68 , a thermal head  69 , a platen roller  70 , master cutting means  71  and a roller pair  72  for conveyance. The stencil storing means  68  is adapted to support a stencil roll  73   a  such that the stencil roll  73   a  is freely rotatable and dismountable. 
   The thermal head  69 , including a number of heat generating devices, is supported by side walls, not shown, included in the master making section  67  and has a heat generating surface constantly pressed against the platen roller  70  by biasing means not shown. The platen roller  70  is rotatably supported by the side walls of the master making section  67  and rotated by a stepping motor not shown. 
   The master cutting means  71  includes a stationary edge affixed to the master making section  67  and a movable edge movable relative to the stationary edge. The movable edge is moved relative to the stationary edge by being rotated or moved in the up-and-down direction to thereby cut a stencil  73  at a preselected length and produce a master therefrom. The roller pair  72  is made up of a drive roller rotated by drive means, not shown, and a driven roller pressed against the drive roller so as to be rotated thereby. The drive roller and driven roller cooperate to convey the master made by the thermal head  69  and platen roller  70  toward the printing section  36 . 
   The master making section  67  with the above configuration selectively makes a master  73  for simplex printing formed with a single image or a divided master  73  for duplex printing formed with a first and a second image side by side. In the illustrative embodiment, the maximum print size available with the print drum  37  is assumed to be A 3 , so that the maximum size of an image to be formed in the master  73  for simplex printing is A 3  while the maximum size of each of the first and second images to be formed in the divided master  73  is A 4 . 
   A sheet discharging section  74  is arranged below the master making section  67  and includes a peeler  75 , a peel fan  76 , a sheet conveyor  77  and a print tray  78 . The peeler  75  is angularly movably supported by the side walls of the printer body at its base end and driven by peeler drive means, not shown, such that the end having an acute angle is selectively movable toward or away from the circumferential surface of the print drum  37 . The peel fan  76  is mounted on the printer body and adapted to send air toward the position where the peeler  75  and print drum  37  adjoin each other. The peeler  75  and peel fan  76  cooperate to peel off a sheet carrying an image thereon, i.e., a print from the circumference of the print drum  37 . 
   The sheet conveyor  77  is positioned below the peeler  75  and provided with a conventional configuration including a drive roller, a driven roller, a plurality of parallel, endless belts passed over the drive roller and driven roller and formed with holes, and a suction fan. A sheet or print is conveyed by the endless belts to the left, as viewed in  FIG. 4 , while being retained thereon by the suction fan. 
   A print tray  78  is positioned at the left-hand side of the conveyer  77  and includes a single end fence  78   a  and a pair of side fences not shown. The end fence  78   a  is movable in the direction of sheet conveyance while the side fences are selectively movable toward or away from each other in the widthwise direction of a sheet, neatly positioning sheets, or prints, sequentially stacked on the print tray  33 . 
   The sheet feeding section mentioned earlier is located at the lower right of the printing section  36 , although not shown specifically, and adapted to feed sheets to the printing section  36  one by one. The sheet feeding section includes a sheet tray, a pickup roller, sheet separating means and a registration roller pair  79 . The pickup roller and sheet separating means are configured to pay out top one of a number of sheets stacked on the sheet tray while separating it from underlying sheets. The registration roller pair  79  is provided with a conventional configuration for stopping the sheet paid out from the print tray and then driving it toward the printing section  36  by being rotated at preselected timing such that the sheet meets an image formed in the master  73 . 
   A master discharging section, not shown, is arranged at the upper right of the printing section  36  and adapted for peeling off a used master from the print drum  37  and discarding it. The master discharging section includes a discharge roller pair, waste master box and a compression plate. The discharge roller pair picks up the edge of a used master away from the surface of the print drum  37  and conveys it to the waste master box. Thereafter, the compression plate compresses the used master dropped into the waste master box. Such a configuration of the master discharging section is also conventional. 
   The operation of the stencil printer  35  in accordance with the illustrative embodiment will be described hereinafter. The stencil printer  35  is operable in either one of a simplex print mode and a duplex print mode as selected on a control panel, not shown, by the operator of the printer  35 . A simplex print mode operation will not be described specifically because it is identical with the operation of the stencil printer  1 ,  FIG. 1 , executed after the peeler  40  has been moved to the first position. 
   Assume that the operator, selected the duplex print mode, sets two documents on an image scanning section, not shown, provided on the top of the printer body and then pushes a perforation start key positioned on the control panel. Then, the document scanning section reads the two documents one by one while the master discharging section peels off a used master from the print drum  37  and discards it. Subsequently, the print drum  37  is rotated to its home position where the clamper  42  is located substantially at the top and then stopped there. Thereafter, the clamper  42  is opened by opening/closing means not shown. In this condition, the stencil printer  35  awaits arrival of a master. This is followed by a master making operation. 
   The master making operation begins with causing the stepping motor and drive means to rotate the platen roller  70  and roller pair  72  for thereby paying out the stencil  73  from the stencil roll  73   a . The stencil  73  thus paid out is selectively perforated, or cut, by the heat generating devices of the thermal head  69  while being conveyed via the thermal head  69 , so that a first and a second image are formed in the stencil  73 . The stencil  73  with the first and second images is then conveyed by the platen roller  70  and roller pair  72  toward the clamper  42  held in the open position on the print drum  37 . 
   When the leading edge of the stencil  73  is brought to a preselected position between the stage  41  and the clamper  42 , as determined by control means not shown, in terms of the number of steps of the stepping motor, the opening/closing means closes the clamper  42  in order to retain the leading edge of the stencil  73  on the print drum  37 . Subsequently, the print drum  37  is driven to rotate clockwise, as viewed in  FIG. 4 , at a peripheral speed identical with the stencil conveying speed, so that the stencil  73  is wrapped round the print drum  37 . When the stencil  73  is wrapped round the print drum  29  by a length corresponding to a single master, as also determined by the control means in terms of the number of steps of the stepping motor, the platen roller  70  and roller pair  72  are caused to stop rotating while the cutting means  71  is driven to cut off the divided master  73  from the stencil  73 . Thereafter, the divided master  73  is pulled out from the master making section  67  by the print drum  37 , which is in rotation. As soon as the print drum  37  is again rotated to its home position, it is brought to a stop. This is the end of a master making and wrapping operation. 
   The master making and wrapping operation stated above is followed by a master adhering operation. More specifically, the print drum  37  is caused to start rotating at a low speed while a single sheet is fed from the sheet feeding section and nipped by the registration roller pair  79 . The registration roller pair  79  is again driven at a timing when the leading edge of the first image formed in the master  73  reaches a position where it faces the press roller  38 . At this instant, among the cam plates constituting the cam groups  53 , cam plates that cause the press roller  38  to contact the print drum  37  over the first range are selected while the path selector  40  is located at the second position. Just after the rotation of the registration roller pair  79 , the larger diameter portions of the above cam plates move away from the can followers  52  with the result that the press roller arms  48  are angularly moved under the action of the tension springs  56 , pressing the press roller  38  against the outer periphery of the print drum  37  via the divided master  73 . As a result, the ink applied to the inner periphery of the print drum  37  by the ink roller  46  is transferred to the sheet via the porous portion of the print drum  37 , mesh screen and perforations formed in the first image of the divided master  73 , causing the master  73  to adhere to the print drum  37 . 
   The sheet with the ink transferred thereto, as stated above, is peeled off from the print drum  37  by the path selector  40  held in the second position and dropped and then has its leading edge nipped by the movable guide  58  held in the first position. Subsequently, the movable guide  58  is moved to the second position at the sheet conveying speed, i.e., the peripheral speed of the print drum  37  and press roller  38 , temporarily storing the sheet or simplex print on the top of the refeed conveyor  57 . 
   Before the print drum  37  is caused to complete one full rotation to bring the leading edge of the second image of the divided master  73  to a position where it faces the press roller  38 , the refeed conveyor  57  is operated to again feed the sheet temporarily stored to the gap between the press roller  38  and the refeed conveyor  57 . The sheet is then conveyed by the press roller  38  along the circumference of the press roller  38  while being guided by the roller guide plate  55  and is again brought to the gap between the print drum  37  and the press roller  38 . At this instant, among the cam plates of the cam groups  53 , cam plates that cause the press roller  38  to contact the print drum  37  over the second range are selected while the path selector  40  is switched from the second position to the first position. After the operation of the refeed conveyor  57 , the lager diameter portions of the above cam plates move away from the cam followers  52  with the result that the press roller arms  48  are angularly moved under the action of the tension springs  65 , again causing the press roller  38  to contact the print drum  37 . 
   When the press roller  38  is again pressed against the print drum  37 , as stated above, the ink applied to the inner periphery of the print drum  37  by the ink roller  45  is transferred to the sheet via the porous portion of the print drum  37 , mesh screen and perforations forming the second image of the master  73 , causing the second image to adhere to the print drum  37 . Subsequently, the sheet thus carrying the ink on the reverse surface thereof, i.e., duplex print is steered to the sheet discharging section  74  by the path selector  40 , which is held in the first position this time, peeled off from the print drum  37  by the peeler  75  and peel fan  76 , dropped and then driven out to the print tray  78  by the conveyor  77 . In this condition, the stencil printer  35  remains in the stand-by condition. 
   When the operator presses a trial print key, not shown, also provided on the control panel, the print drum  37  is rotated at a higher speed than during the master adhering operation while another sheet is fed from the sheet feeding section. This sheet, like the previous sheet, is pressed against the print drum  37  by the press roller  38 , peeled off from the print drum  37  and then steered to the refeed conveyor  57  as a simplex print. Subsequently, the sheet is again fed by the refeeding device to the gap between the print drum  37  and the press roller  38  and then driven out to the print tray  78  as a duplex trial print. 
   The operator then checks the density, position and so forth of each image printed on the trial print, adjusts such factors on various keys arranged on the control panel, produces another trial print, sets a desired number of prints and a desired print speed, and then pushes a print start key on the control panel. In response, the print drum  37  is driven at a peripheral speed corresponding to the desired print speed while sheets are fed from the sheet feeding section one by one. At this time, after the first sheet has been steered to the refeed conveyor  57 , cam plates included in the cam groups  53  and allowing the press roller  38  to contact the print drum  37  over the third range are selected. Consequently, the second sheet, like the first sheet, is conveyed to the refeed conveyor  57  while the first sheet is again fed from the refeed conveyor  57  to the printing section  36 . 
   Just before the trailing edge of the second sheet arrives at the path selector  40 , the path selector  40  is switched from the second position to the first position for steering the first sheet carrying the second image thereon, i.e., duplex print toward the print tray  78  via the sheet discharging section. Just after the trailing edge of the first sheet, the path selector  40  is returned from the first position to the second position. Subsequently, a third sheet is fed from the sheet feeding section, so that the first image is transferred to the third sheet. The procedure described so far is repeated thereafter. 
   After the last sheet, carrying the first image thereon, has been guided to the refeed conveyor  57 , the cam plates of the cam groups  53  that set up the second contact range of the press roller  38  with the print drum  37  are selected. Consequently, after the second image has been transferred to the reverse surface of the last sheet, the sheet is guided by the path selector  40  to the sheet discharging section  74  and then stacked on the print tray  78 . Thereafter, the stencil printer  35  again remains in the stand-by position with the print drum  37  being held in the home position. 
   Assume that a jam occurs during the above master adhering, trial printing or actual printing operation, e.g., a sheet conveyed by the registration roller pair  79  or the refeeding means  39  gets under or wraps round the press roller  38 . Then, in response to information output from a sensor, not shown, the operation of the stencil printer  35  is stopped as soon as the print drum  37  is brought to a position where the clamper  42  is located substantially at the bottom. At this instant, the larger diameter portions of any of the cams included in the cam groups  53  are held in contact with the cam followers  52 , holding the press roller  38  in the released position. 
   Subsequently, the operator unlocks the support member  49  from the printer body by operating a locking device, pulls out the support member  49  toward the operator along the guide members  51 , and then removes the jamming sheet. The operator then returns the support member  49  to a preselected position in the printer body and again locks the former to the latter. Thereafter, if the printing operation has been interrupted halfway, remaining part of the printing operation is effected. If desired, the support member  49  may be automatically mounted to or dismounted from the printer body by use of a lead screw or a motor by way of example. Also, the support member  49  may be provided with holding means for holding the press roller  38  in the released position. 
   As stated above, in the illustrative embodiment, a sheet, jamming any position around the press roller  38  or the refeeding means  39 , can be removed after the support member  49  with the press roller  38  and refeeding means  39  has been pulled out from the printer body and therefore efficiently in a broad space outside of the printer body. In addition, it is possible to noticeably enhance the efficiency of replacement of the press roller  38  or the efficiency of replacement or adjustment of the refeeding means  39  and other parts mounted on the support member  49 . 
     FIG. 7  shows a third embodiment of the stencil printer in accordance with the present invention. As shown, the third embodiment is identical with the second embodiment except that the support member  49  is replaced with a first and a second support members  80  and  81  and in that the refeed conveyor  57  is supported by the support member  81  in such a manner as to be angularly movable about and removable from the support member  81 . In  FIG. 7 , structural elements identical with those shown in  FIG. 4  are designated by identical reference numerals, and detailed description thereof will not be made in order to avoid redundancy. 
   The first support member  80  and second support member  81  support the press roller arms  48  and cam groups  53  and the refeed conveyor  57 , respectively. The support member  80  can be freely pulled out from the printer body along rails or similar guide members  82  mounted on the printer body. Likewise, the support member  81  can be pulled out from the printer body along rails or similar guide members  83  similar to the guide members  82 . Usually, the support members  80  and  81  each are locked to the printer body by a respective locking device. 
   With the above construction, the third embodiment achieves the same advantages as the second embodiment. In addition, in the third embodiment, the press roller  38  and moving means  66  and the refeed conveyor  57  can be pulled out from the printer body independently of each other, promoting efficient removal of a jamming sheet or efficient replacement or maintenance. 
   In the first embodiment, the support member  15  is configured such that it can be pulled out from the printer body  23 . Likewise, in the second and third embodiments, the support members  49  and  80  and  81 , respectively, are configured such that they can be pulled out from the printer body not shown. Alternatively, the support member  15 ,  49 ,  80  and  81  each can be configured to be bodily removable from the associated printer body in order to make, e.g., the replacement of various parts more efficient. 
   A fourth embodiment of the stencil printer in accordance with the present invention will be described with reference to  FIG. 8 . The fourth embodiment is generally identical with the second embodiment except that a printer body  88  is substituted for the printer body, not shown, that the support member  49  can be pulled out from the printer body  88 , and that a discharge member  89  is provided on the support member  49  for discharging, when the support member  49  is pulled out from the printer body  88 , a sheet laid on the refeed conveyor  57  to the outside of the printer body  88  together with the refeed conveyor  57 . 
   More specifically, as shown in  FIG. 9 , the discharge member  89  is implemented by a plate having a generally L-shaped section as seen in a cross-section; the upright portion of “L” decreases in height toward the downstream side in the direction of sheet conveyance. The discharge member  89  is affixed to the deepest side of a top plate  57   a , which forms part of the refeed conveyor  57 , so as not to interfere with a sheet P being conveyed by the refeed conveyor  57  when the stencil printer is in operation. 
   The movable guide  58  is positioned downstream of the refeed conveyor  57  in the direction of sheet conveyance in order to nip the leading edge of a sheet carrying an image on one surface thereof, i.e., a simplex print coming out of the printing section  36 , as stated previously.  FIG. 10  shows a conventional movable guide  58  similar to a movable guide  81  taught in Laid-Open Publication No. 2005-125716. As shown, the movable guide  58  includes a pair of side plates  58   b  (only one is visible) on which rollers  58   a  are rotatably mounted and supported by rails not shown, mounted on the printer body  88 . So long as the leading edge of a sheet P laid on the refeed conveyor  58  is positioned on the movable guide  58 , the leading edge of the sheet P is left on the movable guide  58  disposed in the printer body even if the support member  49  is pulled out from the printer body  88 , resulting in a sheet jam. 
   In light of the above, as shown in  FIG. 11 , the movable guide  58  included in the illustrative embodiment is made up of a guiding member or first member  58   d  and a laying member or second member  58   e  constructed integrally with each other. The guiding member  58   d  includes side plates  58   c  (only one is visible; not shown in  FIG. 9 ), rotatably supporting rollers  58   a  while the laying member  58   e  allows the leading edge of the sheet P to be laid thereon. A space  58   f  is provided between the bottom of the guiding member  58   d  and the top of the laying member  58   e  in order to allow the sheet P to be discharged to the outside of the printer body. 
   In the above construction, even if the support member  49  is pulled out from the printer body  88  with the sheet P being laid on the refeed conveyor  57 , the discharge member  89 , pulled out together with the support member  49 , forces the side edge of the sheet P outward for thereby preventing the sheet P from being left in the printer body  88  and bringing about a jam. The illustrative embodiment is therefore successful to promote more efficient removal of a jamming sheet or more efficient replacement or maintenance of various parts than the second embodiment. 
   While the discharge member  89  has been shown and described as being applied to the support member  49  of the second embodiment, it is similarly applicable to the support member  81  of the third embodiment for achieving the above effect. 
     FIG. 12  shows a fifth embodiment of the stencil printer in accordance with the present invention. The fifth embodiment is identical with the first embodiment except that a print drum  84  removably mounted to the printer body  23  is substituted for the print drum  5 . 
   In the illustrative embodiment, ink feeding means similar to that of the print drum  5  is arranged in the print drum  84  while a stage and a clamper are mounted on the circumferential surface of the print drum  84 , although not shown specifically. An ink pump and an ink pack, not shown, are provided integrally with the print drum  84 . A rail member  84   a  is mounted on the top of the print drum  84  while a knob  84   b  is affixed to the end of the print drum  84  corresponding to the front end of the printer body  23 . To mount the print drum  84  to the printer body  23 , the operator fits the rail member  84   a  in a rail guide, not shown, mounted on the printer body  23  and then slides the print drum  84  into the printer body  23 . 
     FIG. 13  shows locking means  85  for selectively locking or unlocking the print drum  84  to the printer body  23 . As shown, the locking means  85  is made up of a restricting member  85   a  angularly movably supported by the printer body  23  at one end and having a hook-like free end, a pull-type solenoid  85   b  mounted on the printer body  23  and having a plunger  85   c  movably engaged with the restricting member  85   a , and a tension spring  85   d  constantly biasing the restricting member  85   a  clockwise as viewed in  FIG. 9 . When the print drum  84  is inserted into the printer body  23  to a preselected position in a condition wherein the solenoid  85   b  is not energized, the free end of the restricting member  85   a  catches a preselected portion of the print drum  84  under the action of the tension spring  85   d  to thereby lock the print drum  84  to the printer body  23 . 
     FIG. 14  shows a specific arrangement of unlock switches arranged on the top front of the printer body  23 . As shown, the unlock switches are implemented as switches  86  and  87  to which LEDs (Light Emitting Diodes)  86   a  and  87   a , respectively, are assigned. Assume that the operator mounts the support member  15  and print drum  84  to the printer body  23  to a position where the support member  15  and print drum  84  are locked to the printer body  23  by a locking device, not shown, and restricting means  85 , respectively, and then pushes the switch  86 . Then, the LED  86   a  is turned on while the solenoid  85   b  is energized to angularly move the restricting member  85   a  counterclockwise, as viewed in  FIG. 13 , to thereby unlock the print drum  84  from the print drum  23 , allowing the print drum  84  to be removed from the printer body  23 . When the operator pushes the other switch  87 , the LED  87   a  is turned on while the locking device similar in configuration to the restricting means  85  is operated to unlock the support member  15  from the printer body  23 , allowing the support member  15  from being removed from the printer body  23 . 
   In the above configuration, sensing means, not shown, responsive to the support member  15  pulled out from the printer body  23  may be used to maintain the solenoid  85   b  turned off even if the operator pushes the switch  86  when the support member  15  is held in a position pulled out from the printer body  23 , thereby inhibiting the print drum  84  from being dismounted from the printer body  23 . This successfully prevents the circumferential surface of the print drum  84  from contacting, e.g., the press roller  6  or the moving means  22  mounted on the support member  15 , which is pulled out from the printer body  23 , and being damaged thereby when mounted to or dismounted from the printer body  23 , thereby obviating defective printing. 
   Likewise, sensing means, not shown, responsive to the print drum  84  pulled out from the printer body  23  may be used to maintain the locking device, not shown, inoperative even if the operator pushes the switch  87  when the print drum  84  is held in a position pulled out from the printer body  23 , thereby inhibiting the support member  15  from being dismounted from the printer body  23 . This successfully prevents any part mounted on the support member  15  from contacting and damaging the circumferential surface of the print drum  84  when mounted to or dismounted from the printer body  23 , thereby obviating defective printing. 
   While the print drum  84  removable from the printer body  23  has been shown and described as being applied to the first embodiment in place of the print drum  5 , such a print drum may be similarly applied to any one of the second to fourth embodiments, if desired. When the print drum  84  is applied to the second or the fourth embodiment, the mounting/dismounting of the print drum  84  or the pullout/insertion of the support member  49  will be controlled in accordance with the position of the support member  49  or the position of the print drum  84 , respectively. Likewise, when the print drum  84  is applied to the third or the fourth embodiment, the mounting/dismounting of the print drum  84  or the pullout/insertion of the support members  80  and  81  will be controlled in accordance with the positions of the support members  80  and  81  or the position of the print drum  84 . 
   In summary, it will be seen that the present invention provides a stencil printer allowing the operator of the printer to remove a sheet jammed around pressing means after pulling out a support member from a printer body toward the operator and therefore in a broad space, thereby noticeably enhancing efficient work. In addition, even the replacement of the pressing means or the replacement or adjustment of any other part mounted on the support member can be efficiently performed. 
   Further, the stencil printer of the present invention is configured to inhibit a print drum from being dismounted from the printer body when the support member is held in a position pulled out from the printer body. This prevents the circumferential surface of the print drum from contacting the pressing means or moving means supported by the support member and being scratched or otherwise damaged thereby when mounted to or dismounted from the printer body, also obviating defective printing. 
   Various modifications will become possible for those skilled in the art after receiving the teachings of the present disclosure without departing from the scope thereof.