Japanese Patent No. 3649728 (FIG. 1 to FIG. 4, page 2 to page 5) shows conventional features known in the art including a coin selector which has a con passage provided along a guide rail and a diameter sorting unit that is a real/fake discriminating unit disposed in the coin passage. A diameter of a coin moving on the guide rail while rolling in the coin passage is selected by the diameter sorting unit. Only a coin having a predetermined diameter passes through the diameter sorting unit to be received as a real coin. A plurality of photoelectric sensors are disposed in the coin passage in order to detect reception of the real coin, and processing of signals from the coin sensors are devised to prevent illegal action.
JP-A-05-282514 (FIGS. 2 to 4, page 2 to page 4) is a second conventional arrangement known in the art. This reference discloses an apparatus where a fake coin is sorted in a sorting portion disposed in a route where a coin inserted from a slot port rolls in a coin passage. A coin is sorted to a receiving portion or a cancel passage by switching a passage switching portion disposed downstream of the sorting portion. A pass detecting portion is disposed between the sorting portion and the switching portion. A slotting detecting portion is disposed downstream of the switching portion. A detection signal of a coin is output only when a detection signal from the slotting detecting portion is received within a predetermine time period after a coin is detected at the pass detecting portion.
In recent years, a problem of illegal action regarding the coin selector according to Japanese Patent No. 3649728 arises wherein an erroneous determination is made as if a real coin has been detected by slotting a plate-like tool whose distal end is attached with an infrared light emitter from the coin slotting port of the game machine and properly causing the light emitter to emit light to cause the coin sensor to transmit a detection signal in a pseudo manner so that a coin(s) is acquired irregularly.
According to JP-A-05-282514, since the slotting detecting portion is disposed at a position where the coin passage forms a right angle, it is difficult to insert a tool for conducting illegal action so that security to illegal action is improved as compared with Japanese Patent No. 3649728. However, according to JP-A-05-282514, since the sorting portion, a direction changing portion (the passage switching portion), and the slotting detecting portion are arranged in series, the apparatus is increased in size, so that it may not installed in a predetermined range in the pachinko-slot machine.