The present invention relates to a printer which executes printing in such a manner that a type wheel rotates in order to set one of the types thereon into a printing position where the print hammer accordingly strikes it.
In the conventional printers of this kind, unless the type at the printing position is exactly opposite to the print hammer, the print hammer does not hit the type squarely and a corresponding character is not printed clearly. To solve this problem, one conventional printer has been provided with a print hammer where contact with each type in the printing position is adjustable. More particularly, before this printer is transported from the factory, the attached position of the print hammer is adjusted to establish the best contact of the print hammer with each type on the type wheel in the following manner: a specific device provided for the position-adjustment rotates the type wheel in simulation of the printing action so as to set one of the types into its printing position. Owing to this conventional position-adjusting device, the printer can print more clearly than those printers in which attachment of the print hammer is not adjustable.
As the printer is being used after transportion from the factory, the position of the print hammer will be occasionally displaced relative to the types due to a change in the motor's characteristic or a vibration by the motor. However, the user of this printer does not have such a position adjusting device that is usually used in the factory for adjusting the position of the print hammer before transportation. Thus, the user has to send the printer out for repair so as to adjust the print hammer to an appropriate position.
More specifically, a type is set into the printing position for printing, and its actual stop position slightly differs from that of the others depending on: the weight of a spoke of each type of the type wheel; the accuracy of the motor for rotating the type wheel; and the rotational direction of the type wheel. Therefore, it is necessary to adjust the attached position of the print hammer for the best contact with each type by means of the specific position-adjusting device. Even if the user wants to adjust the position of the print hammer relative to the types without this position-adjusting device, he or she can adjust it only relative to a predetermined type which is set in the printing position whenever the printer stops.