the invention is described more fully below in conjunction with the attached diagrams . this invention includes the step of , when a golf ball molded from a golf ball - forming material is to be administered subsequent treatment at a specific surface site , positioning the specific surface site on the ball at a given location . for example , as shown in fig1 , after a ball on which an identifying mark has been formed by molding is subjected to various surface treatments , the specific site is positioned by means of the identifying mark , following which marking is administered and painting is carried out , thereby giving a finished golf ball . “ golf ball - forming material ” refers herein to the materials in the respective parts of the golf ball , such as the core and the cover . the core may be any of various types of cores , such as a single - layer solid core , a solid core having a plurality of vulcanized rubber layers , a solid core having a plurality of resin layers , and a thread - wound core having a rubber thread layer . examples of materials for this purpose include known rubber materials and thermoplastic materials . the cover is a part formed over the core . the cover material is preferably a known thermoplastic resin or thermoplastic elastomer composed primarily of an ionomer resin or a urethane resin . the cover is not limited to one layer , and may be formed so as to have a multilayer construction of two or more layers . concurrent with or subsequent to the molding of the above golf ball - forming material , an identifying mark is applied to the surface of each ball . examples of the identifying mark used on the invention include a marking formed by the mold cavity , a marking formed with special ink , and a punched mark . in connection with the above invention , the present applicant earlier filed u . s . patent application ser . no . 11 / 392 , 586 . the invention to which this earlier application relates is a golf ball , and a golf ball - forming mold , on which a recessed and / or raised mark has been formed near a seam line on the surface of the ball so as to enable the position and direction of the seam line to be easily identified . it is suitable to employ the foregoing recessed and / or raised mark as the identifying mark used in the present invention . for further details , reference should be made to u . s . patent application ser . no . 11 / 392 , 586 . various subsequent treatments are administered to the ball molded from the above - mentioned golf ball - forming material . examples of such subsequent treatment include treatment in which the seam line formed on the ball surface is inspected , treatment in which a marking or stamp is applied to the ball surface , and treatment in which injection molding pin marks formed on the surface of the ball are removed . it is essential that positioning of a specific site on the ball surface for administering such treatment be carried out before the subsequent treatment step . it is desirable that , for example , the positional relationship between the identifying mark and the seam line , the positional relationship between the seam line and the place where a marking is to be applied , and the positional relationship between the identifying mark and the place where a marking is to be applied , be understood beforehand . a preferred embodiment of the invention involving treatment in which a marking or stamp is applied onto the seam line is described below in conjunction with fig2 . the positioning apparatus 1 in fig2 has a feeder 2 in which a plurality of balls g are lined up , a turntable 6 which intermittently transfers balls g to a predetermined location , a first rotating station 3 , a second rotating station 4 and a third rotating station 5 which are provided on the turntable and are capable of rotating the ball in one or a plurality of directions , a final correcting station 9 which corrects the orientation of the ball to a predetermined state , and a conveyor 7 which carries out of the apparatus the ball whose orientation has been properly corrected at the correcting station . also shown in the diagram is a ball discharge outlet 8 which is connected to a marking or stamping device . the turntable 6 turns intermittently about an axis of rotation 61 . a ccd or other type of image processing camera is disposed directly above the ball turning means . this image processing camera photographs from directly above the ball an identifying mark that has been formed on the ball surface . each of the plurality of balls g lined up in the ball feeder 2 has a seam line ( specific surface site ) located at a random position thereon . these balls g are each delivered in turn onto the turntable 6 , and the positioning of the respective balls is carried out . referring to fig3 a , when the ball g is photographed with an image processing camera 30 , by situating the camera so as to photograph the ball g from directly above and turning the ball g , the identifying mark on the surface of the ball is detected , then moved to the top of the ball g . referring to fig3 b , from information provided by the identifying mark now situated at the top of the ball , the specific site is corrected so as to face in the inspection or marking position . specifically , use is made of means for rotating the ball g in the directions of the mutually orthogonal x -, y - and z - axes . here , as shown in fig3 a , the first rotating station 3 and the second rotating station 4 are used as the means for rotating the ball in the x - axis and y - axis directions . as shown in fig3 b , the third rotating station 5 is used as the means for rotating the ball g in the z - axis direction and as the means for correcting the specific site . at the first rotating station 3 and the second rotating station 4 , rotating means 10 connected to a drive means such as a motor are disposed on both sides of the ball g , and the ball is clamped between the rotating means 10 and turned . at the third rotating station 5 , a turning means 60 which rotates the ball g about the z axis in fig3 b is used . that is , the first rotating station 3 and the second rotating station 4 rotate the ball g by the respective turning means while the identifying mark on each ball is detected with the image processing camera 30 . in this case , if necessary , the ball is re - clamped from the x - axis to the y - axis , and the ball is rotated about the x and y axes . when the operation at the first rotating station 3 is complete , the ball g is transferred by the turntable 6 to the second rotating station 4 . when operation at the second rotating station 4 is complete , the ball g is then transferred by the turntable 6 to the third rotating station 5 . this sequence is as indicated by the arrows within the turntable 6 in fig2 . at the third rotating station 5 , as shown in fig3 b , the ball g is rotated about the z - axis based on image data obtained from image processing at the second rotating station 4 , thereby placing the identifying mark at a given position at the top of the ball g . next , because this identifying mark already has a fixed positional relationship with the specific surface position , by using a rotating means 10 ′ provided at the third rotating station 5 to rotate the ball through a given angle , the specific surface site ( seam line ) is appropriately moved to the top of the ball ( that is , the top on the axis of the rotating means 10 ′). referring to fig4 , the manner in which the ball is rotated until the orientation of the identifying mark at the very top of the ball has been corrected is explained . first , the first rotating station 3 rotates the ball about the axis of rotation in fig4 a , thereby moving a t - shaped identifying mark that has been formed on the ball surface onto the dashed line serving as the axis of rotation and into the position shown in fig4 b . next , the second rotating station 4 rotates the ball about the axis of rotation in fig4 b , thereby moving the t - shaped identifying mark to the center onto the axis of rotation ( dashed line ) which is perpendicular to that in fig4 a and into the position shown in fig4 c . then , at the third rotating station 5 , the ball is rotated in the direction of the arrow in fig4 c , thereby rotating the t - shaped identifying mark into the proper position as shown in fig4 d . the specific site ( seam line ) is placed at the top of the ball by the above - described turning means 10 ′. however , the turntable 6 , in transferring the ball to the outlet side , sets the ball in a state that is rotated through a fixed angle as seen from directly above , as a result of which the specific site ( seam line ) ends up out of position by a given angle . hence , the disposition of the specific site ( seam line ) is corrected to the proper position by the final correcting station 9 . the final correcting station 9 has the above - described turning means , the mechanism for which is similar to that indicated by the symbol 60 for the third rotating station 5 . fig5 shows the photographed surface of the ball after the ball has been positioned by the third rotating station 5 ; that is , after the ball has been turned through a given angle from the identifying mark that was at the very top , based on information provided by the mark , and arranged with the seam line at the very top ( center ) of the ball . the vertical line at the center of this image frame f is the seam line l , the symbol o is the center of the captured image , the symbol p is the t - shaped identifying mark , and the symbol d is a dimple . next , the ball is placed on the conveyor 7 with the seam line ( specific surface site ) correctly disposed at the top of the ball , and transferred to the discharge outlet 8 . the ball is then subjected to subsequent treatment in which a marking such as lettering , a trade mark or a design is marked or stamped onto the seam line of the ball . the identifying mark formed on the surface of the ball in the above embodiment is effectively employed to position the ball for the marking operation that follows . that is , the identifying mark that has been formed on the ball surface is discerned with an image processing camera and , based on the shape of the identifying mark , the direction and position of the seam line on the ball can be determined . as described above , a ball positioning operation is then reliably and smoothly carried out by rotating the ball a specific amount to correct its orientation so that the seam line is positioned at the very top ( center ) of the ball . in another embodiment of the invention , as shown in fig6 , a new , fourth rotating station 30 may be added between the third rotating station 5 and the final correcting station 9 for the purpose of inspecting processing marks ( e . g ., flash marks and gate marks ) present on the seam line . the mechanism for this fourth rotating station 30 is similar to that of the second rotating station 4 . some preferred embodiments of the invention have been described above in detail with reference made to the attached drawings . however , the golf ball manufacturing method of the invention is not limited to these embodiments and drawings , and various modifications may be made thereto without departing from the gist of the invention . for example , in fig2 , the orientation of the ball was corrected to a given position by rotating the ball in three separate steps . however , an orientation correcting means other than this may be used . as described above , the golf ball manufacturing method of the invention carries out the operation of , based on information provided by an identifying mark formed on the surface of the ball , correcting to a reference orientation a ball which is to be administered subsequent treatment and on which a specific surface site has been positioned at a predetermined location . as a result , a specific surface site having any random location can be reliably positioned at a predetermined location , which positioning operation is smoothly and very efficiently carried out . this is highly beneficial for the manufacture of golf balls .
this invention provides a golf ball manufacturing method to be administered subsequent treatment at a specific site on the surface of a ball molded from a golf ball - forming material . the method includes the steps of forming on the surface of the ball an identifying mark having a given positional relationship with the specific surface site ; removing each ball in turn from a plurality of lined - up balls on each of which the specific surface site is located in a random position ; photographing the identifying mark formed on the surface of the ball with an image processing camera ; and , based on information provided by the photographed identifying mark , correcting the orientation of the ball so that the specific surface site lies at the position where the subsequent treatment will be administered . this method of manufacture enables the ball to be reliably and smoothly positioned , thus making it possible to reliably and smoothly carry out subsequent treatment such as seam line processing and marking . the overall efficiency of the golf ball manufacturing process is thus increased , which is advantageous for production .