Abstract:
A sheet supply apparatus includes a sheet supply member for supplying printing sheets, a separating member movably situated adjacent to the sheet supply member, a pressing member movably situated adjacent to the separating member, an urging device disposed near the pressing member for urging the pressing member toward the separating member so that the separating member contacts the sheet supply member, and an adjusting device connected to the urging device for adjusting an urging force exerted on the pressing member by the urging device. The adjusting device includes a rotationally operating portion and a rotationally adjusting portion connected to the rotationally operating portion. The rotationally adjusting portion is situated adjacent to the pressing member and the urging member to adjust the urging force while being operated by the rotationally operating portion.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a sheet supply apparatus of a so-called frictional separating method type. The sheet supply apparatus of such type can separate a sheet from sheets stacked therein by utilizing friction between a sheet supply roller and a separating plate. 
     2. Description of the Related Art 
     A sheet supply apparatus is such a machine that separates and feeds out stacked sheets one by one. Such sheet supply apparatus is usually installed in a printing machine, for example. 
     FIGS. 8 to  10  illustrate one example of such conventional sheet supply apparatus. 
     The sheet supply apparatus includes a sheet supply roller  1  and a separating base  2 . The sheet supply roller  1 , a separating member, is situated to a predetermined position and driven to rotate. The separating base  2 , a separating member, is situated below the sheet supply roller  1 . 
     The sheet supply roller  1  includes a core  3  and a roller member  4  integrally connected to an outer circumferential surface of the core  3 . The core  3  is connected to a sheet supply shaft  5 . The sheet supply shaft  5  is connected to a not-shown drive shaft. 
     The separating base  2  includes a high-friction member  6  and a curved stainless plate member  7  situated to a sheet-entrance side of the base. The sheet supply roller  1  contacts the high-friction member  6  of the separating base  2 . Sheets fed thereto are separated from each other so that only one of the sheets can be conveyed forward. 
     A supporting plate  8  is fixed to a predetermined position. A lever  10  is pivotally movably attached to the supporting plate  8  by a support screw  9 . The separating base  2  is attached to the lever  10  by a pin  11  so as to rotate around the pin. The separating base  2  can be detached from the pin  11 . The supporting plate  8  has an attachment plate  12  integrally formed therewith. Through holes  8   a  and  12   a  are formed in a bottom of the supporting plate  8  and the attachment plate  12 , respectively. A pressing pole  13  as a pressing member is inserted through the through holes  8   a  and  12   a.  The pressing pole  13  can move vertically along an axial direction of itself. A flange  14  is attached to the pressing pole  13  between the bottom of the supporting plate  8  and the attachment plate  12 . An adjusting plate  15  as adjusting means is slidably situated on an upper surface of the bottom of the supporting plate  8 . The adjusting plate  15  is longitudinal in a sliding direction of itself and narrow in a width direction. A slit  16  is formed in the adjusting plate  15  along the longitudinal direction thereof. The pressing pole  13  is inserted through the slit. An operating surface  17  is formed on both sides of the slit  16  on an upper surface of the adjusting plate  15 . A height of the operating surface  17 , i.e. a thickness of the adjusting plate  15 , changes gradually along the longitudinal direction of the adjusting plate  15 . One end portion of the adjusting plate  15  is designated as an operating end  18  and situated inside a casing of the present sheet supply apparatus. And, a spring  19  as urging means is disposed around the pressing pole  13  between the flange  14  and the adjusting plate  15 . 
     In the constitution explained above, sheets are rubbed between the sheet supply roller  1  and the separating base  2 , and conveyed forward by the sheet supply roller  1 . When a plurality of the sheets reaches the separating base  2  while stacking with each other, the sheets are separated by the sheet supply roller  1  and the separating base  2  so that only one sheet can be conveyed forward. Here, the order F A . F C . F B  is preferable where F A  is a frictional force exerted between the sheet supply roller  1  and the printing sheet, F B  is a frictional force exerted among the printing sheets, and F C  is a frictional force exerted between the printing sheet and the separating base  2 . 
     If difference among the frictional forces is not sufficient, the printing sheet may not be conveyed, or a plurality of the printing sheets is conveyed while not being separated from each other. The former phenomenon is called “conveyance failure”, and the latter “multiple conveyance”. 
     The adjusting means explained above is used to properly arrange the difference among the frictional forces. The surface of the printing sheet is rough because it is composed of intertwined fibers. When the sheet supply roller  1  of a soft material is pressed against the printing sheet so that a nip width in which the printing sheet is held is enlarged, the frictional force between the sheet supply roller  1  and the printing sheet is enlarged and stabilized. If the nip width is small, the frictional force tends to decrease due to surface abrasion of the sheet supply roller  1  and paper powder generated from the printing sheets. Since many types of the printing sheets are in use, the frictional force among the sheets is varied accordingly. Therefore, stable conveyance of the printing sheet of many types inevitably requires the above-explained adjusting means for adjusting separating pressure. The separating pressure is to be adjusted by users so as to conform to a type of the sheet to be used. 
     In the constitution explained above, the pressing pole  13  is elastically urged upward by the spring  19  relative to the supporting plate  8 . A top end of the pressing pole  13  presses up the lever  10 . The separating base  2  attached to the lever  10  is urged upward to contact the sheet supply roller  1 . 
     The separating pressure exerted on the sheet supply roller  1  by the separating base  2  can be adjusted by operating the adjusting plate  15 . A user is to detach a part of a casing of the present apparatus to expose the operating end  18 . The user is to take the operating end  18  and pull the adjusting plate  15  to slide along the longitudinal direction thereof. When the adjusting plate  15  thus slides, the height of the operating surface  17  of the adjusting plate  15  is changed at a position where the spring  19  is disposed. FIGS. 8 and 10 show that the spring  19  is supported by a relatively low operating surface  17 , which means the separating pressure is small. FIG. 9 shows that the spring  19  is supported by a relatively high operating surface  17 , which means the separating pressure is large. 
     After the adjustment is finished, the part is attached to the casing, and then the sheet supply apparatus is actually operated to feed the printing sheets, so that effect of adjusting the separating pressure is confirmed. If no effect is confirmed, the part of the casing is again detached and the adjustment is conducted once more. 
     In the conventional sheet supply apparatus as stated above, elastic force of the spring  19  is changed by sliding the adjusting plate  15 . Accordingly, the adjusting plate  15  is required to be made in a longitudinal form along the sliding direction. Additionally, any other parts or members can not be allowed to be placed in a space where the adjusting plate  15  slides so as to prevent interference therewith. Thus, in the conventional sheet supply apparatus, an inside space thereof is not utilized effectively. 
     In the conventional sheet supply apparatus, the slidable adjusting plate  15  is downsized to its limit so as to utilize any of the inside space. Accordingly, the operating end  18  of the adjusting plate  15  must be placed inside the apparatus. This means that the operating end  18  cannot project out the apparatus. Therefore, when adjustment of the separating pressure is needed, the casing must be opened by detaching the part therefrom. 
     In the conventional sheet supply apparatus, since the longitudinal adjusting plate  15  slides along the longitudinal direction thereof, a groove  8   b  must be formed in the supporting plate  8  for guiding the adjusting plate  15  to slide therein. This groove  8   b  deteriorates strength of the supporting plate  8 . 
     This invention is made to solve the problems as explained above. An object of the present invention is to provide a sheet supply apparatus which is enough compact to be situated in a small space and can be easily operated from the outside thereof. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the present invention, there is provided a sheet supply apparatus comprising a sheet supply member for supplying printing sheets; a separating member movably situated adjacent to the sheet supply member; a pressing member movably situated adjacent to the separating member; an urging device disposed near the pressing member for urging the pressing member toward the separating member so that the separating member contacts the sheet supply member;, and an adjusting device connected to the urging device for adjusting an urging force exerted on the pressing member by the urging device, the adjusting device including a rotationally operating portion and a rotationally adjusting portion connected to the rotationally operating portion, the rotationally adjusting portion being situated adjacent to the pressing member and the urging member and adjusting the urging force while being operated by the rotationally operating portion. 
     According to a second aspect of the present invention, there is provided a sheet supply apparatus comprising a sheet supply roller for supplying printing sheets; a separating member pivotally movably situated adjacent to the sheet supply roller; a pressing member movably situated adjacent to the separating member for pressing the separating member toward the sheet supply roller; an operating portion pivotally movably situated adjacent to the pressing member; an urging device situated between the pressing member and the operating portion, the urging device urging the pressing member toward the separating member; rotationally adjusting portion cooperating with the operating portion, the rotationally adjusting portion moving the operating portion while being rotated so that an urging force exerted on the separating member by the urging device through the pressing member is adjusted; and a rotationally operating portion connected to the rotationally adjusting portion for rotating the rotationally adjusting portion. 
     According to a third aspect of the present invention, there is provided a sheet supply apparatus comprising a sheet supply roller for supplying printing sheets; a separating member pivotally movably situated adjacent to the sheet supply roller; a pressing member movably situated adjacent to the separating member for pressing the separating member toward the sheet supply roller; a cam rotatably situated adjacent to the pressing member; an urging device situated between the pressing member and the cam, the urging device urging the pressing member toward the separating member; and a rotationally operating portion connected to the cam for rotating the cam so that an urging force exerted on the separating member by the urging device through the pressing member is adjusted. 
     A sheet supply apparatus as defined in a fourth aspect of the present invention, in the second aspect of the present invention, further comprises a case containing the sheet supply roller and the separating member therein, and the rotationally operating portion is operated from an outside of the case. 
     A sheet supply apparatus as defined in a fifth aspect of the present invention, in the second aspect of the present invention, further comprises a fixing device situated at the rotationally operating portion, and the fixing means fixes the rotationally operating portion to an optional position in a rotational direction thereof. 
     A sheet supply apparatus as defined in a sixth aspect of the present invention, in the third aspect of the present invention, further comprises a case containing the sheet supply roller and the separating member therein, and the rotationally operating portion is operated from an outside of the case. 
     A sheet supply apparatus as defined in a seventh aspect of the present invention, in the third aspect of the present invention, further comprises a fixing device situated at the rotationally operating portion, and the fixing device fixes the rotationally operating portion to an optional position in a rotational direction thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view, partially sectioned, of a first embodiment in a condition where a separating pressure is small; 
     FIG. 2 is a side view, partially sectioned, of the first embodiment in a condition where the separating pressure is large; 
     FIG. 3 is an elevation view, partially sectioned, of the first embodiment in a condition where the separating pressure is small; 
     FIG. 4 is a side view, partially sectioned, of a second embodiment in a condition where a separating pressure is small; 
     FIG. 5 is a plan view of adjusting means of the second embodiment; 
     FIG. 6 is a side view, partially sectioned, of the second embodiment in a condition where the separating pressure is large; 
     FIG. 7 is an elevation view, partially sectioned, of the second embodiment in a condition where the separating pressure is small; 
     FIG. 8 is a side view, partially sectioned, of a conventional sheet supply apparatus in a condition where a separating pressure is small; 
     FIG. 9 is a side view, partially sectioned, of a conventional sheet supply apparatus in a condition where a separating pressure is large; 
     FIG. 10 is a combination of an elevation view, partially sectioned, of a conventional sheet supply apparatus in a condition where a separating pressure is small and a plan view of adjusting means. 
    
    
     DETAILED DESCRIPTION 
     FIGS. 1 to  3  show a first embodiment of a sheet supply apparatus of the present invention. 
     The sheet supply apparatus includes a sheet supply roller  1  situated to a predetermined position as a sheet supply member and a separating base  2  situated below the sheet supply roller  1  as a separating member. The separating base  2  has a high-friction member  6  and a curved stainless plate member  7  situated to an entrance side of a printing sheet. The sheet supply roller  1  contacts the high-friction member  6  of the separating base  2 . Sheets fed thereto are separated from each other so that only one of the sheets can be conveyed forward. 
     The sheet supply roller  1  includes a core  3  and a roller member  4  integrally connected to an outer circumferential surface of the core  3 . The core  3  is connected to a sheet supply shaft  5 . The sheet supply shaft  5  is connected to a not-shown drive shaft. 
     A supporting plate  8  is fixed to a predetermined position. A lever  10  is pivotally movably attached to the supporting plate  8  by a support screw  9 . The separating base  2  is attached to the lever  10  by a pin  11  so as to be rotationally movable around the pin  11 . The separating base  2  can be detached from the pin  11 . The supporting plate  8  has an attachment plate  12  integrally formed therewith. An operating plate  20  as an operating portion is attached to the supporting plate  8  by the support screw  9 . A forward end portion of the operating plate  20  protrudes over each of forward end portions of the supporting plate  8  and the separating base  2 . The operating plate  20  and the separating base  2  are rotationally movable relative to the supporting plate  8  in an independent manner with each other. 
     Through holes  8   a,    20   a,  and  12   a  are formed in a bottom of the supporting plate  8 , a forward portion of the operating plate  20 , and the attachment plate  12 , respectively. A pressing pole  13  as a pressing member is inserted through the through holes  8   a,    20   a,  and  12   a.  The pressing pole  13  can move axially vertically. A flange  14  is attached to an upper portion of the pressing pole  13  between the operating plate  20  and the attachment plate  12 . And, a spring  19  as urging means is fitted on the pressing pole  13  between the flange  14  and the operating plate  20 . The spring  19  urges the pressing pole  13  toward the separating base  2 . 
     The sheet supply apparatus includes adjusting means for adjusting the urging force of the spring  19 . The adjusting means includes a rotationally adjusting portion  30  for pivotally moving the operating plate  20  and a rotationally operating portion  40  for operating the rotationally adjusting portion  30 . The rotationally adjusting portion  30  has an adjusting shaft  31 . The adjusting shaft  31  is supported by a bearing  32  situated to a predetermined position in a case  100 . The bearing  32  applies appropriate rotational resistance to the adjusting shaft  31  so that the adjusting shaft  31  can be optionally positioned in a rotational direction. A pin  33  is attached to a circumferential surface of one end of the adjusting shaft  31 . The pin  33  can contact the operating plate  20 . Accordingly, if the adjusting shaft  31  is rotated, the pin  33  moves the operating plate  20 . The other end of the adjusting shaft  31  protrudes outside the case  100  of the apparatus. To the protruding end of the shaft, an adjusting knob  41  is attached as the rotationally operating portion. 
     According to the constitution explained above, the pressing pole  13  is urged upward relative to the supporting plate  8  by elasticity of the spring  19 . The top end of the pressing pole  13  pushes up the lever  10 . The separating base  2  attached to the lever  10  is urged upward to contact the sheet supply roller  1 . 
     To adjust the separating pressure acting between the sheet supply roller  1  and the separating base  2  contacted therewith, the adjusting knob  41  is rotated. Hence, the adjusting shaft  31  is rotated so that the pin  33  turns, thereby moving the operating plate  20 . In this way, the height of the operating plate  20  on which the spring  19  is supported is adjusted. FIGS. 1 and 3 illustrate a condition where the operating plate  20  is positioned low and the separating pressure is small. FIG. 2 illustrates a condition where the operating plate  20  is positioned high and the separating pressure is large. 
     After adjustment, the sheet supply apparatus is operated to feed printing sheets actually, so that whether the adjustment of the separating pressure is satisfactory can be confirmed. If not, the adjusting knob  41  can be operated outside the apparatus. It is not necessary to detach a part of the case and operate the inside mechanism. 
     According to the present embodiment, the separating pressure acting between the sheet supply roller  1  and the separating base  2  is determined by the urging force of the pressing pole  13 , and the urging force is adjusted by the operating plate  20  moved by the pin  33  of the rotating adjusting shaft  31 . Therefore, in comparison with the conventional adjustment mechanism with the sliding longitudinal cam plate, the adjusting means of the present embodiment occupies smaller space inside the apparatus. Additionally, operation of the present apparatus is convenient since it can be conducted from outside of the case  100  by the adjusting knob  41 . 
     FIGS. 4 to  7  illustrate a second embodiment of the sheet supply apparatus of the present invention. 
     This sheet supply apparatus has adjusting means structurally different from that of the first embodiment. Substantially the same portions as that of the first embodiment will be referred to by the reference numerals of FIGS. 1 to  3 , and explanation thereof may be omitted. 
     The adjusting means of the present embodiment includes a cam  50  of a disc-form as the rotationally adjusting portion for adjusting the urging force of the spring  19 . A supporting shaft  51  is formed on the upper surface of the supporting plate  8 . The supporting shaft  51  is inserted into a supporting hole formed in the center of the cam  50  so that the cam  50  can rotate relative to the supporting plate  8 . The cam  50  has a groove  52  circumferentially formed in an upper surface thereof. And, an operating surface  53  is formed on the upper surface of the cam  50  along the groove  52  for operating the pressing pole  13 . The height of the operating surface  53 , a thickness of the cam  50 , changes gradually along the circumferential direction of the cam. 
     The pressing pole  13  is inserted through the groove  52 . The pressing pole  13  is axially vertically movable. A flange  14  is attached to an upper portion of the pressing pole  13  between the cam  50  and the attachment plate  12 . And, a spring  19  as urging means is fitted on the pressing pole  13  between the flange  14  and the cam  50 . A washer  54  as receiving means is situated between the lower end of the spring  19  and the cam  50 . The spring  19  urges the pressing pole  13  toward the separating base  2  relative to the supporting plate  8 . When the cam  50  rotates, the operating surface  53  of the cam  50  moves up and down, thereby changing a force of the spring  19  that urges the pressing pole  13  upward. 
     An outer circumferential surface of the cam  50  is formed as a warm wheel  55 . The warm wheel  55  engages a warm  56 . The warm  56  is attached to one end of a warm shaft  57 . The warm shaft  57  is rotatably supported by a not-shown bearing and protruding outside the case  100 . To the other end of the warm shaft  57  outside the case  100 , an adjusting knob  60  as the rotationally operating portion is attached. Rotation of the adjusting knob  60  makes the cam  50  to rotate. 
     In the constitution as stated above, the pressing pole  13  is urged upward relative to the supporting plate  8  by an elastic force of the spring  19 . The top of the pressing pole  13  pushes up the lever  10 . The separating base  2  attached to the lever  10  is urged upward to contact the sheet supplying roller  1 . 
     To adjust the separating pressure acting between the sheet supply roller  1  and the separating base  2  contacted therewith, the adjusting knob  60  situated outside the present apparatus is rotated. Hence, the warm shaft  57  is rotated so that the cam  50  turns, thereby adjusting the pressing force of the spring  19 . FIGS. 4 and 7 illustrate a condition where the operating surface  53  for pressing the spring  19  is positioned low so that the pressing force of the spring  19  is adjusted to be small. This is the case where the separating pressure is adjusted to be small. FIG. 6 illustrates a condition where the operating surface  53  for pressing the spring  19  is positioned high so that the pressing force of the spring  19  is adjusted to be large. This is the case where the separating pressure is adjusted to be large. 
     After adjustment, the sheet supply apparatus is operated to feed printing sheets actually, so that whether the adjustment of the separating pressure is satisfactory can be confirmed. If not, the adjusting knob can be operated outside the apparatus. It is not necessary to detach a part of the case and operate the inside mechanism. 
     According to the present embodiment, the separating pressure acting between the sheet supply roller  1  and the separating base  2  is determined by the urging force of the pressing pole  13 , and which force is adjusted by the rotating cam  50 . Further, the cam  50  is rotated by the warm  56  and the warm wheel  55 . Therefore, in comparison with the conventional adjustment mechanism with the sliding longitudinal cam plate, the adjusting means of the present embodiment occupies smaller space inside the apparatus. Additionally, the present apparatus is convenient in use since it can be operated from outside of the case  100  by the adjusting knob  60 . 
     The sheet supply apparatus of the present invention as explained above can be applicable to various kinds of machines that need function of separating stacked sheets. For example, the invention can be applied to a printing machine or a gathering machine for feeding printed sheets into a plurality of bins. 
     According to the present invention, in a sheet supply apparatus in which printing sheets are separated by a sheet supply member and a separating member, a force urging the separating member to contact the sheet supply member is adjusted by a rotationally adjusting portion and a rotationally operating portion associated therewith. Therefore, the present invention facilitates more effective utilization of the space inside the apparatus in comparison with the conventional adjusting member of the sliding constitution. Additionally, operation is easy in the apparatus of the present invention since it can be conducted from the outside thereof Further, since it is not necessary to form a groove in a structural member of the apparatus for guiding the conventional adjusting member to slide therein, strength of the structural member does not deteriorate. 
     Thus, the present invention can provide the sheet supply apparatus that is enough compact to be situated in a small space and includes the separating pressure adjusting mechanism that is operable from the outside thereof.