Appearance inspection machine for flat tablet

An appearance inspection apparatus for a flat tablet which picks up and fetches images of a front surface, a reverse surface and an overall side face of a non-circular flat tablet such as an elliptic flat tablet or an elongated elliptic flat tablet, processes the fetched images to detect whether or not the flat tablet has a defective appearance, and separately recovers unacceptable flat tablets having a defective appearance and acceptable flat tablets having a non-defective appearance, comprising:

• a roller belt including a plurality of rollers connected for rotation in a bridging manner between a pair of endless sprocket chains and being circulated at a predetermined speed;
• a tablet supplying section for supplying any of the flat tablets in an uprightly erected posture with a diametrical direction of the flat tablets directed in an upward and downward direction onto said roller belt;
• a guide path formed from and between a pair of guide walls disposed in a spaced relationship by a predetermined distance from each other in the proximity of an upper face of said roller belt on the downstream side in the circulation direction of said roller belt with respect to said tablet supplying section;
• a front surface image pickup apparatus for picking up an image of the flat tablet placed in the uprightly erected posture on and transported by said roller belt to fetch a front surface image of the flat tablet;
• a reverse surface image pickup apparatus for picking up an image of the flat tablet placed in the uprightly erected posture on and transported by said roller belt to fetch a reverse surface image of the flat tablet;
• a first side face image pickup apparatus for picking up an image of a half periphery portion of a side face of the flat tablet placed in the uprightly erected posture on and transported by said roller belt to fetch an image of an overall periphery of a side face of the flat tablet;
• a posture changing section provided on said guide path on the downstream side in the transport direction with respect to the position at which side face image pickup by said first side face image pickup apparatus is performed and including an inclined portion along which said guide path is gradually inclined to one side and an increased width portion provided contiguously to said inclined portion and capable of placing the flat tablet in a horizontally lying posture with a thickness-wise direction of the flat tablet directed in an upward and downward direction onto said roller belt;
• and
• a second side face image pickup apparatus for picking up an image of the flat tablet transported in the horizontally lying posture after the posture change by said posture changing section to fetch an image of the remaining half periphery portion of the side face of the flat tablet;
• and wherein
• a flat tablet supplied from said tablet supplying section is held in an uprightly erected posture between adjacent ones of said rollers of said roller belt so that the flat tablet is transported in and along said guide path while keeping the uprightly erected posture, and while the flat tablet is transported, a front surface image of the flat tablet is picked up from one side in a direction perpendicular to the transport direction by said front surface image pickup apparatus whereas a reverse surface image of the flat tablet is picked up from the opposite side in the direction perpendicular to the transport direction by said reverse surface image pickup apparatus and an image of a half periphery portion of a side face of the flat tablet is picked up from above by said first side face image pickup apparatus, whereafter an image of the flat tablet after the posture of the flat tablet is changed into a horizontally lying posture by said posture changing section from the one side in the direction perpendicular to the transport direction by said second side face image pickup apparatus to fetch an image of the remaining half periphery portion of the side face of the flat tablet.