Abstract:
A detector detects a size of a recording medium stored in a tray of a device. The tray includes a first regulating member that can slide in a width direction of the recording medium, and a second regulating member that can slide in a feed direction of the recording medium. A first movable member engages with the first regulating member, and a second movable member, overlapped by the first movable member, engages with the second regulating member. Both the first and second movable members rotate around a common pivot and include convex members on peripheral edges thereof. Switches are selectively pressed by the convex members when the tray is attached to the device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present document incorporates by reference the entire contents of Japanese priority document, 2004-331145 filed in Japan on Nov. 15, 2004.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a mechanism for detecting the size of a paper sheet stored in a paper feed tray of an image forming apparatus.  
         [0004]     2. Description of the Related Art  
         [0005]     An image forming apparatus generally includes box shaped paper feeding trays for storing or stacking paper sheets of various sizes. A paper feeder picks up an appropriate paper sheet and feed the paper sheet to relevant parts of the image forming apparatus.  
         [0006]     In conventional image forming apparatuses, a user indicated the size of paper sheets loaded in the feeding tray with a manual operation. However, if the user makes an error, the error cannot be confirmed by the image forming apparatus, it results in a paper jam. Japanese Patent Laid-Open Publication No H11-165881 and Japanese Patent Laid-Open Publication No 2002-187626 disclose paper feeders that can automatically detect the paper size. However, these paper feeders can detect the paper size only in the paper feed direction, but not in the paper width direction. Although some paper feeders detect the paper size both in the paper feed direction as well as in the paper width direction, commonly used paper feeders can only approximately detect the paper size. This results in limitations on the detected paper sizes and a need to provide a plurality of paper size detecting sensors, thus increasing the cost.  
         [0007]     The image forming apparatus is generally provided with a paper separating member that separates the top sheet from the other sheets in the paper feeding tray before feeding the top sheet. The paper separating member includes a feed roller that is stopped from rotation immediately when there is a failure in identification of the paper size or an error in setting of the paper size. This results in an increase in slipping of paper sheets, thereby lowering the accuracy of paper sheet transfer, and affecting productivity.  
         [0008]     To overcome the aforementioned drawbacks, an automatic paper size detecting tray has been developed. Such a paper size detecting tray includes a lever that detects the paper size. The lever engages with a regulating member that regulates the paper in a paper width direction. For the sake of convenience for the user, the regulating member and a lock are preferably positioned at the front side of the paper size detecting tray. However, a paper size detecting switch to be pressed by the lever is positioned at the back side of the paper size detecting tray. Therefore, the lever is inevitably engaged with the regulating member at the back side. When the lever is engaged with the regulating member at the front side, shaking of a rack and a pinion and precision accumulation from other units are caused. This causes a shift in the position of the regulating member engaged with the lever, which leads to inaccurate paper size detection.  
       SUMMARY OF THE INVENTION  
       [0009]     It is an object of the present invention to at least solve the problems in the conventional technology.  
         [0010]     According to an aspect of the present invention, a detector for detecting a size of a recording medium in a device includes a tray that stores the recording medium to be fed to the device, the tray being detachably attached to the device, including a first regulating member capable of sliding in a width direction of the recording medium according to the size, and a second regulating member capable of sliding in a feed direction of the recording medium according to the size, a first movable member that engages with the first regulating member, rotates around a pivot in conjunction with the first regulating member, and includes a plurality of first convex members on a peripheral edge thereof, a second movable member, overlapped by the first movable member, that engages with the second regulating member, rotates around the pivot in conjunction with the second regulating member, and includes a plurality of second convex members on a peripheral edge thereof equidistant from the pivot with the first convex members, and a plurality of switches that are selectively pressed by a combination of the first convex members and the second convex members when the tray is attached to the device.  
         [0011]     According to another aspect of the present invention, an image forming apparatus includes a detector for detecting a size of a recording medium in a device, including a tray that stores the recording medium to be fed to the device, the tray being detachably attached to the device, including a first regulating member capable of sliding in a width direction of the recording medium according to the size, and a second regulating member capable of sliding in a feed direction of the recording medium according to the size, a first movable member that engages with the first regulating member, rotates around a pivot in conjunction with the first regulating member, and includes a plurality of first convex members on a peripheral edge thereof, a second movable member, overlapped by the first movable member, that engages with the second regulating member, rotates around the pivot in conjunction with the second regulating member, and includes a plurality of second convex members on a peripheral edge thereof equidistant from the pivot with the first convex members, and a plurality of switches that are selectively pressed by a combination of the first convex members and the second convex members when the tray is attached to the device.  
         [0012]     The other objects, features, and advantages of the present invention are specifically set forth in or will become apparent from the following detailed description of the invention when read in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a perspective view of a paper feed tray and a paper size detector according to an embodiment of the present invention;  
         [0014]      FIG. 2  is a drawing of a structure of a paper size detecting mechanism according to the embodiment;  
         [0015]      FIG. 3  is a perspective view of the paper feed tray shown in  FIG. 1  without a chassis;  
         [0016]      FIG. 4  depicts a pressing operation of switches of a paper size detecting sensor shown in  FIGS. 1 and 2 ;  
         [0017]      FIG. 5  is a drawing of the paper feed tray before attachment to an image forming apparatus;  
         [0018]      FIG. 6  is a drawing of a change in position, as compared to  FIG. 4 , of peripheral convex members of a first lever shown in  FIG. 3 ;  
         [0019]      FIG. 7  is a drawing of a shape of the first lever;  
         [0020]      FIG. 8  is a drawing of a shape of a second lever shown in  FIG. 3 ;  
         [0021]      FIG. 9  is a cross sectional view of the paper feed tray in the paper feed direction;  
         [0022]      FIG. 10  is a cross sectional view of the paper feed tray in the paper width direction;  
         [0023]      FIG. 11A  through  FIG. 11F  depict pressed conditions of the push switches of the paper size detecting sensor;  
         [0024]      FIG. 12  depicts a table of pattern combinations of peripheral convex members of the first lever and the second lever;  
         [0025]      FIG. 13  depicts lock mechanisms of the end fence and the side fence shown in  FIG. 1 ;  
         [0026]      FIG. 14  is a detailed drawing of the lock mechanism of an anterior side fence shown in  FIG. 13 ;  
         [0027]      FIG. 15  is a detailed drawing of the lock mechanism of a posterior side fence shown in  FIG. 13 ;  
         [0028]      FIG. 16  depicts a structure that determines positions of the posterior side fence according to standard paper sizes;  
         [0029]      FIG. 17  is a drawing of a pawl that prevents slipping of the posterior side fence from the paper feed tray;  
         [0030]      FIG. 18  is perspective view of a False Rejection Rate (FRR) separating device used as a paper feeder; and  
         [0031]      FIG. 19  is a drawing of an image forming apparatus. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]     Exemplary embodiments of the present invention are explained next with reference to the accompanying drawings.  
         [0033]      FIG. 1  is a perspective view of a box shaped paper feed tray  23  and a paper size detecting sensor  51  according to an embodiment of the present invention. Paper sheets  53  are loaded in the paper feed tray  23  after opening the upper surface. The loaded paper sheets  53  are regulated by means of movable side fences  54  and a movable end fence  52 .  
         [0034]      FIG. 2  is a drawing of a structure of a paper size detecting mechanism that engages with the end fence  52  and one of the side fences  54  of the paper feed tray  23 .  FIG. 3  is a drawing of the paper feed tray  23  without a chassis. The paper feed tray  23  is provided with a floor plate  5  that elevates the loaded paper sheets to facilitate paper transfer. The loaded paper sheets are regulated by means of the side fence  54  that can slide in the paper width direction along a slit provided at the bottom of the paper feed tray  23 . Similarly, the loaded paper sheets are also regulated in the paper feed direction by means of the end fence  52  that can slide in the paper feed direction along another slit provided at the bottom of the paper feed tray  23 . An engaging spindle  3  of the end fence  52  positioned on the back side of the paper feed tray  23  extends via a slit provided in the paper feed tray  23  to another slit provided in the core of a second lever  2 . By sliding the end fence  52  in the paper feed direction, the engaging spindle  3  of the end fence  52  moves along the slit provided in the second lever  2 , and the second lever  2  turns along a turning pivot  41  shown in  FIG. 3  and  FIG. 4 . As shown in  FIG. 3  and  FIG. 5 , the side fence  54  is moved in the paper width direction along racks  7 ,  8 , and a pinion gear  9 . An engaging spindle  4  provided on a posterior side fence  54   a  (shown in  FIG. 3 ) extends via a slit in the paper width direction provided on the paper feed tray  23  to a slit provided on a first lever  1 . By sliding the posterior side fence  54   a , the engaging spindle  4  moves along the slit provided in the first lever  1 , and the first lever  1  turns along the turning pivot  41 .  
         [0035]     As shown in  FIG. 2  through  FIG. 4 , the paper size detecting sensor  51  is pressed by convex members on the peripheral edge of both the first lever  1  and the second lever  2 . As shown in  FIG. 3 , push switches A through E of the paper size detecting sensor  51  can be selectively pressed to output respective ON signals. As shown in  FIG. 5 , an arrow  6  indicates a setting direction of the paper feed tray  23 . Thus, one of the side fences  54  is on the anterior side, and the other is on the posterior side. When the paper feed tray  23  is set, the paper size detecting sensor  51  provided on the image forming apparatus is pressed against by convex members on the peripheral edge of the first lever  1  and the second lever  2 .  
         [0036]      FIG. 4  and  FIG. 6  are drawings of a change in the convex members that press the push switches of the paper size detecting sensor  51  based on a movement of the first lever  1  and the second lever  2  due to movement of the side fence  54  and the end fence  52 . The change in the convex members is explained in detail with reference to  FIG. 7  through  FIG. 9 .  FIG. 7  is a drawing of the first lever  1  that is fan shaped.  FIG. 8  is a drawing of the second lever  2  that is similar in shape to a ginkgo biloba leaf. The first lever  1  and the second lever  2  are positioned to overlap each other and are fixed to turn around the centerline of the common turning pivot  41 . Both the first lever  1  and the second lever  2  are formed of a single plate shaped member. Both the first lever  1  and the second lever  2  include an arc shaped periphery that is equidistant from the center of the turning pivot  41 . A plurality of first convex members  127  are formed on the arc shaped periphery of the first lever  1  and a plurality of second convex members  128  are formed on the arc shaped periphery of the second lever  2 . A first slide groove  129  is provided on the first lever  1  along a direction that intersects the slit of the paper feed tray  23 . In other words, the first slide groove  129  extends in a direction that intersects with the sliding direction of the side fence  54 . The engaging spindle  4  of the side fence  54  is slidably connected to the first slide groove  129 . Due to this, when the side fence  54  is made to slide in a direction perpendicular to the paper feed direction, the engaging spindle  4  slides in the slit and the first slide groove  129 , and the first lever  1  turns around the centerline of the turning pivot  41 . A second slide groove  131  is provided on the second lever  2  along a direction that intersects the other slit on the paper feed tray  23 . In other words, the second slide groove  131  extends in a direction that intersects with the sliding direction of the end fence  52 . The engaging spindle  3  of the end fence  52  is slidably connected to the second slide groove  131 . Due to this, when the end fence  52  is made to slide in the paper feed direction, the engaging spindle  3  slides in the slit and the second slide groove  131 , and the second lever  2  turns around the centerline of the turning pivot  41 .  
         [0037]     Because the first lever  1  and the second lever  2  are positioned to overlap each other, the first convex members  127  of the first lever  1  and the second convex members  128  of the second lever  2  are also positioned to overlap each other. Combined convex members  133  are formed due to overlapping of the first convex members  127  and the second convex members  128 . The combined convex members  133  form a pattern to press the push switches of the paper size detecting sensor  51 . An overlapping state of the first lever  1  and the second lever  2  is shown in  FIG. 9 .  FIG. 9  is a cross sectional view of the paper feed tray  23  in the paper feed direction. The engaging spindle  4  of the side fence  54  engages with the first lever  1 , and the second lever  2  is overlapped by the first lever  1 .  FIG. 10  is a cross sectional view of the paper feed tray  23  in the paper width direction. Engagement of the second lever  2  with the engaging spindle  3  of the end fence  52  is shown.  
         [0038]     An overlapped state of the first convex members  127  and the second convex members  128  changes according to the turning of the first lever  1  and the second lever  2  around the centerline of the turning pivot  41 , thereby changing the dimension and the position of the combined convex members  133  along the direction of the array of push switches that are provided on the paper size detecting sensor  51 . In other words, the dimension and the position of the combined convex members  133  change according to the size of the paper sheets that are loaded in the paper feed tray  23 . The paper size detecting sensor  51  is provided inside the image forming apparatus along the edge in the setting direction  6  of the paper feed tray  23 , and includes push switches  51 A through  51 E that are selectively pressed by the combined convex members  133 .  
         [0039]      FIG. 11A  through  FIG. 11F  are drawings of pressed condition of the push switches  51 A through  51 E by means of the first convex members  127 , the second convex members  128 , and the combined convex members  133  when the paper feed tray  23  loaded with paper sheets of predetermined sizes is set in the image forming apparatus.  FIG. 11A  and  FIG. 11B  are drawings of a positional relation between the push switches  51 A through  51 E and the first convex members  127 . The push switches  51 B and  51 C opposite the first convex members  127  are pressed by the first convex members  127  and are turned ON.  FIG. 11C  and  FIG. 11D  are drawings of a positional relation between the push switches  51 A through  51 E and the second convex members  128 . The push switches  51 B,  51 D, and  51 E opposite the second convex members  128  are pressed by the second convex members  128  and are turned ON.  FIG. 11E  and  FIG. 11F  are drawings of a positional relation between the push switches  51 A through  51 E and the combined convex members  133 . The push switches  51 B,  51 C,  51 D, and  51 E opposite the combined convex members  133  are pressed by the combined convex members  133  and are turned ON. Pattern combinations of the aforementioned convex members are shown in a table in  FIG. 12 . Entries A through E in the table indicate each of the push switches  51 A through  51 E respectively of the paper size detecting sensor  51  that is shown in  FIG. 3  and  FIG. 4 . A switch that is turned OFF (switch not pressed: concave pattern) is indicated by “0”, and a switch that is turned ON (switch pressed: convex pattern) is indicated by “1”. A switch that is not pressed completely (an operation error) is indicated by “0.5”.  
         [0040]     It is not easy to make the shape of the convex members to match with the spacing between the push switches  51 A through  51 E of the paper size detecting sensor  51 . There are cases where the edge of the convex members of the second lever  2  barely touch the push switch  51 C, as indicated by  40  in  FIG. 4 . However, during large scale production of images, it is not guaranteed that the convex members of the second lever  2  do not touch the push switch  51 C due to such minute spacing. The aforementioned drawback is overcome by using the convex members of the first lever  1  to press the push switch  51 C. Thus, the convex members of the first lever  1  and the second lever  2  are designed to complement each other. When the image forming apparatus needs to be compact, it is not possible to increase in the spacing between the push switches  51 A through  51 E or to increase in the dimensions of the first convex members  127  and the second convex members  128 . Therefore, the push switches  51 A through  51 E cannot always be pressed properly by using only one of the first convex members  127  or the second convex members  128 . Upon observation, a proper pressing operation of the push switch  51 C can be ensured by using the combined convex members  133 , but not by using only the second convex members  128 . In other words, the first convex members  127  complement the second convex members  128  to ensure that the push switch  51 C is pressed.  
         [0041]      FIG. 13  is a drawing of lock mechanisms of the end fence  52  and the side fence  54 . A flexible arm  103  provided on the end fence  52  includes convex members that engage with concave members  104  provided on the paper feed tray  23  corresponding to standard paper sizes to lock the end fence  52 . As shown in  FIG. 14  ( FIG. 13  partially enlarged), convex members  102   a  provided on a lock lever  102  engage with concave members  105  corresponding to standard paper sizes to lock an anterior side fence  54   b.    
         [0042]     As shown in  FIG. 15 , a latch provided on the edge of a stopper  101   a  that is attached to a lock lever  101  engages with a corresponding latch  106  provided on the paper feed tray  23  to lock the posterior side fence  54   a  that engages with the first lever  1  to detect a paper size. The aforementioned latch mechanism enables locking of the posterior side fence  54   a  according to irregular paper sizes.  
         [0043]     To enhance accuracy of rotating position of the first lever  1 , shaking of rack and pinion of the side fence  54  and precision accumulation from units that are positioned with the aid of the anterior side fence  54   b  need to be prevented. As shown in  FIG. 16 , a convex member  108  provided on the posterior side fence  54   a  engages with a groove  109  provided on the paper feed tray  23 , thereby enabling to determine specific positions of the posterior side fence  54   a  for standard paper sizes. As shown in  FIG. 17 , a pawl  107  prevents slipping of the paper feed tray  23  in the upward direction and strengthens engagement.  
         [0044]     In the present embodiment, a False Rejection Rate (FRR) separating device is used as a paper feeder, which is positioned between a feed roller and a separating member that is pressed against the feed roller. The paper feeder separates and transfers paper sheets. The FRR separating device is explained next. As shown in  FIG. 18 , a pickup roller  63  transfers the uppermost paper sheet from not shown loaded paper sheets to a feed roller  61 . A torque remitter  70  and a reverse roller  62  apply predetermined torque to the feed roller  61 , which rotates in a paper feed direction  65 , in a direction opposite to the paper feed direction  65 . A driven gear  62 A provided on the spindle of the reverse roller  62  engages with a drive gear  62 B to apply the torque that is created due to tooth surface pressure and activation welding force between the drive gear  62 B and the driven gear  62 A. By driving the reverse roller  62  pressed against the feed roller  61  by means of an elastic member  64  (a spring in the present embodiment), the paper sheets are separated and transferred one by one. When using the aforementioned separating mechanism, handling the separation of paper sheets by means of the reverse roller  62  until the paper sheet is disengaged from the feed roller  61  and the reverse roller  62  enables to prevent continuous feeding or feeding of multiple paper sheets resulting from sticking of the paper sheets. However, if the reverse roller  62  is driven when the feed roller  61  is stopped, force is applied in a direction opposite to the paper feed direction  65  due to torque remitter load, thereby resulting in increased slipping of the paper sheets. Although the feed roller  61  needs to be driven to prevent slipping of the paper sheets, the feed roller  61  is stopped before a paper sheet is disengaged from the feed roller  61  to prevent transfer of the subsequent paper sheet to the image forming apparatus. Stopping the feed roller  61  at the appropriate point of time enables to maximize the driving time of the feed roller  61 , thereby minimizing paper slipping. Thus, an accurate knowledge of the paper size can enable a high precision paper transfer.  
         [0045]      FIG. 19  is a drawing of the image forming apparatus that is provided with the paper feed tray according to the embodiment. An image forming unit  100  is provided inside an image forming apparatus  10 . The image forming unit  100  is provided with an image carrier  11  in the form of a drum (photosensitive drum). A charging unit  12 , a developing unit  13 , a printing and transfer unit  14 , and a cleaning unit  15  are positioned around the image carrier  11 . A laser writer  16  is provided above the image forming unit  100 . The laser writer  16  is provided with a not shown light source such as a laser diode, a rotating polygonal mirror for scanning, a polygon motor, an fθ lens, a scanning optical system such as a mirror etc. A fixing unit  17  is provided to the left of the cleaning unit  15 . The fixing unit  17  is provided with a fixing roller  18  having an inbuilt heater, and a pressure roller  19  that is pressed against the fixing roller  18  from below.  
         [0046]     A bifacial unit  22  and four paper feed trays  23  are provided one above the other inside lower part of the image forming apparatus  10 . Sheets such as paper sheets, Over Head Projector (OHP) transparencies etc. are stored in the paper feed trays  23 . A paper refeed path A from the bifacial unit  22  and a supply path B from the paper feed trays  23  lead to a common paper feed path C that extends to the lower side of the image carrier  11  (towards the upper end of paper transfer). The bifacial unit  22  is provided with a reverse path E that is formed by branching of a paper eject path D that extends from outlet port of the fixing unit  17 .  
         [0047]     A contact glass  26  is provided in an image reader  24  of the image forming apparatus  10 . The contact glass  26  is covered with an automatic document transfer unit  27  that is provided above the image forming apparatus  10 . The automatic document transfer unit  27  can open and close by itself. The automatic document transfer unit  27  and an optical reader  20  form an image reader  200 .  
         [0048]     A manual paper feed tray  28  which can open and close by itself is provided on the right surface of the image forming apparatus  10 . The manual paper feed tray  28  directs manually input paper sheets to the paper feed path C. The image forming apparatus  10  is also externally provided with a large scale paper feeder  30 . A large number of paper sheets are movably loaded and stored in the large scale paper feeder  30 . A sheet post processor  31  is externally provided on the left surface of the image forming apparatus  10 . The sheet post processor  31  collects the paper sheets that are ejected via the paper eject path D, and either directly ejects the paper sheets into an upper tray  32 , or carries out a post process such as stapling, punching etc. and ejects the post processed paper sheets into the upper tray  32 , or a lower tray  33 .  
         [0049]     When taking a copy with the image forming apparatus  10 , a document is set in the automatic document transfer unit  27 , or the document is directly set above the contact glass  26  after opening the automatic document transfer unit  27 . Next, a not shown start switch is pressed to drive the automatic document transfer unit  27 . The optical reader  20  reads the document that is transferred above the contact glass  26  of the image reader  24 , or the document that is prior set above the contact glass  26 . Simultaneously, the pick up roller  63  and the feed roller  61  are rotated accordingly to transfer a paper sheet from the cassettes inside the multiple paper feed trays  23  that are provided one above the other inside the image forming apparatus  10 . The paper sheet is inserted into the paper feed path C via the supply path B, transferred by a transfer roller  35  and struck against a resist roller  36 . The resist roller  36  is rotated in synchronization with rotations of the image carrier  11 , and the transferred paper sheet is sent below the image carrier  11  of the image forming unit  100 . To be specific, the paper sheet is sent out from the large scale paper feeder  30  by rotating a pick up roller  37 , inserted into the paper feed path C via a transfer path F, transferred by the transfer roller  35  and struck against the resist roller  36 . Or a paper feed roller  38  provided in a manual paper feeder is rotated and a paper sheet that is set on the opened manual paper feed tray  28  is inserted into the feeder path C, and similarly struck against the resist roller  36 . Next, the resist roller  36  is rotated in synchronization with rotations of the image carrier  11 , and the transferred paper sheet is sent below the image carrier  11  of the image forming unit  100 .  
         [0050]     Upon pressing the not shown start switch, the image carrier  11  of the image forming unit  100  rotates in a clockwise direction. Next, the charging unit  12  uniformly charges the surface of the rotating image carrier  11 . The laser writer  16  carries out writing of data, by means of exposure to a laser beam, according to the data content of the document that is read by the optical reader  20  and forms an electrostatic latent image on the surface of the image carrier  11 . The developing unit  13  converts the electrostatic latent image into a toner image by adding toner. The toner image is printed with the aid of the printing and transfer unit  14  on the paper sheet that is sent below the image carrier  11 . After printing of the toner image, the cleaning unit  15  cleans the surface of the image carrier  11  by removing excess toner, thereby enabling the image carrier  11  to similarly carry out image formation for the next image data. The image carrier  11 , the printing and transfer unit  14 , and the cleaning unit  15 , for example, form a process cartridge unit.  
         [0051]     After printing of the toner image, the paper sheet is transferred by the printing and transfer unit  14 , inserted into the fixing unit  17 , the printed toner image is fixed by means of addition of heat and pressure by the fixing roller  18  and the pressure roller  19  respectively. Next, the paper sheet is ejected to the sheet post processor  31  via the paper eject path D. When forming image on both sides of the paper sheet, the paper sheet having fixed printed image on one side is inserted into the reverse path E midway from the paper eject path D, reversed and refed with the aid of the bifacial unit  22 . A separately formed toner image on the image carrier  11  is printed on the reverse side of the paper sheet by the printing and transfer unit  14 , the printed toner image is fixed by the fixing unit  17 , and the paper sheet is ejected to the sheet post processor  31 .  
         [0052]     According to an aspect of the present invention, a paper sheet size can be detected accurately and reliably. Furthermore, an error in detection of a paper sheet size can be prevented. Moreover, a paper feed tray that accommodates any size of paper sheet can be provided.  
         [0053]     Although the invention has been described with respect to a specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.