TAPE READER

Abstract: A capstan drive type tape reader which facilitates the engagement of a tape. A processor (13) comprises means for measuring the breakdown time of the energization of a feed magnet (4), and means for stopping the energization of a brake magnet (5) when it is detected that the time measured by the measuring means is longer than a predetermined time. When the breakdown time of the ener­ gization of the magnet (4) becomes longer than the predetermined time, the feed magnet (4) and the brake magnet (5) becomes deenergized, a gap is produced be­ tween a capstan roller (2) and a feed roller (3) and between a brake magnet (5) and a brake armature (6), thereby facil­ itating the engagement of a tape.

Description: SPECIFICATION TAPE READER TECHNICAL FIELD The present invention relates to a tape reader of a capstan drive system which is adapted for an easy tape exchange operation. BACKGROUND ART A tape reader of the capstan drive system excites a feed magent to abut a feed roller against a capstan roller for feeding a tape and cuts off the excitation of the feed magnet and excites a brake magnet to stop the tape. That is, when either one of the feed magnet and the brake magnet is excied and the feed magnet is excited, the tape is fed for reading out therefrom information, and until the next readout command is provided, the brake magnet is excited to keep the tape at a standstill. In the case of a tape exchange, it is necessary to cut off the excitation of the feed magnet and the brake magnet to release the tape gripping part; in the past, means has been employed for cutting off the excitation of the feed magnet and the brake magnet by a manual switch or the like. Accordingly, when the tape is exchanged with another after reading out information therefrom, it is necessary to operate the manufal switch or the like, making the tape exchange operation cumbersome. DISCLOSURE OF THE INVENTION The present invention has for its object to automatically interrupt excitation of the feed magnet and the brake magnet, as required, thereby allowing ease in a tape exchange. According to the present invention, when the excitation of the feed magnet is interrupted in excess of a predetermined period of time, the excitation of the brake magnet is also interrupted, and, accordingly, the tape exchange can easily be carried out. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram explanatory of the principal part of an embodiment of the present invention; Fig. 2 is a diagram explanatory of signals a and b in Fig. 1; and Fig. 3 shows an example of a flowchart of a processor. BEST MODE FOR CARRYING OUT THE INVENTION Fig. 1 is a diagram explanatory of the principal part of an embodiment of the present invention. Reference numeral 1 indicates a tape, 2 a capstan roller, 3 a feed roller, 4 a feed magnet, 5 a brake magnet, 6 a brake armature, 7 a light emitting device, 8 a photo detector, 9 and 10 transistors, 11 an output device, 12 an input device and 13 a processor such as a microprocessor. When the processor 13 provides a command for reading out information from the tape 1, a signal a from the output device 11 goes to a 1111 and a signal b goes to a not isto turn ON the transistor 9 and OFF the transistor 10, in consequence of which power source voltage +V is supplied to the feed magnet 4 to excite it, bringing the feed roller 3 into contact with the capstan roller 2 with the tape 1 gripped therebetween, the tape 1 being fed in the direction of the arrow with the rotation of the capstan roller 2. Since light from the light emitting device 7 is incident on the photo detector 8 in accordance with holes punched in the tape 1, punched information of the tape 1 is thus read out and transferred via the input device 12 to the processor 13. Since the processor 13 issues a command for stopping the tape 1 upon completion of the readout of the punched information of one block, the signals a and b from the output device 11 go to a "0" and a "1", respectively. As a result of this, the transistor 9 is turned OFF and the transistor 10 ON, by which the excitation of the feed magnet4 is interrupted and the brake magnet 5 is excited, bringing the brake armature 6 into contact with the tape 1 to stop it. Fig. 2 shows examples of the abovesaid signals a and b. When the signal a is a "1", the signal b is a "0" and the feed magnet 4 is excited but the excitation of the brake magnet 5 is interrupted, feeding the tape 1. On the other hand, when the signal a is a "0", the signal b is a "1" and the excitation of the feed magnet 4 is interrupted but the brake magnet 5 is excited, stopping the tape 1. In an ordinary punched information readout operation, the time during which the brake magnet 5 is excited to stop the tape 1 is about several mS. When the readout of the punched information from the tape 1 is completed, since no command is issued for reading out the tape 1, the signal a goes to a rio", By measuring the time during which the signal a is at "0", it is possible to detect the completion of radout of the punched information from the tape 1. For measuring this time, various arrangements can be utilized, for example, a counter function of the processor 13 can be employed. Fig. 3 illustrates an example of a flowchart of the processor. It is decided whether the signal a is at "O", that is, whether the processor 13 has issued a stop command, and when the signal a is at "0", a counter in the processor is caused to start counting clocks, and then when the count content of the counter reaches a predetermined value, that is, when a predetermined period of time has passed, the processor 13 issues a command for making the signals a and b "ops". In consequence, the excitation of the feed magnet 4 and the brake magnet 5 is interrupted, permitting an exchange of the tape 1. It is also possible to utilize an overflow signal of the counter in this case. Further, the abovesaid predetermined time can be selected to be approximately two seconds. When a readout command is issued to force the signal a to the "1" state before the count content of the counter reaches the predetermined value, the counter is reset, and when the next stop command is issued to force the signal a to the "0" state, the counter starts to count clocks. As the means for measuring the time for interruption of the excitation of the feed magnet 4, it is possible not only to utilize the aforementioned counter in the processor 13 but also to provide a counter which counts clocks when the signal a from the output device 11 to the transistor 9 goes to a "0" and to provide control means for forcing the signal b to the transistor 10 to the "0" state when the count content of the counter reaches a predetermined value. Also it is possible to provide a timer mechanism for performing the same operation as the aforementioned counter. As has been described in the foregoing, the present invention is equipped with means which measures the time for interruption of the excitation of the feed magnet 4, such as a counter or timer, and control means which interrupts the excitation of the brake magnet, too, when it is detected that the time measured by the abovesaid means has exceeded a predetermined time, such as the processor 13 or the like. When the tape 1 is exchanged with another tape after completion of the readout of the punched information of the tape 1, the excitation of the feed magnet 4 and the brake magnet 5 is automatically interrupted. Accordingly, an exchange of the tape 1 does not involve the necessity of manipulating a manual switch or the like; therefore, the present invention has the advantage of improved operability.

Claims: CLAIM A tape reader of a capstan drive system which is provided with a feed magnet which is excited to abut a feed roller against a capstan roller for feeding a tape and a brake magnet which is excited to stop the tape when the excitation of the feed magnet is interrupted, characterized by the provision of means for measuring the time for interruption of the excitation of the feed magnet, and control means for interrupting the excitation of the brake magnet when it is detected that the time measured by the measuring means is in excess of a predetermined value.

Inventors: MIZUNO, YUTAKA
Applicants: FANUC LTD
Application year: 1983
Main classification: G06K13
IPC codes: G11B15, G06K13