Such introduction devices for sheets of paper are known for use in printers, in typewriters or in other apparatuses such as photocopying machines. These known devices use a series of introduction rollers of an appreciable diameter which are associated with the printer cylinder for obtaining a good alignment of the sheet of paper at its introduction.
Recently, it has become important to develop printers or typewriters of a very small size, of the so-called portable type. The devices for introducing paper of these printers had necessarily to be reduced in size. Instead of a series of introduction rollers associated with the printer roller, attempts have been made at using solely a cylinder of a small diameter, which however resulted in a poor alignment of the sheet inside the printer.