An image forming apparatus comprises a plurality of decks for accommodating sheets, a feeder for feeding sheets from said decks, an image forming unit for forming an image on a sheet fed by said feeder, a detector for detecting thicknesses or colors of the sheets accommodated in said decks, an input unit for designating a desired thickness or color of the sheet, and a control unit for controlling said feed means to feed the sheet of the desired thickness or color from said decks.

A shoe in the form of a cylindrical screw is rotatably threaded through a carriage supporting a print head and has one end held slidably against a guide rail parallel to a main guide shaft on which the carriage is movable parallel to the platen of an impact printer. The shoe is rotated about its own axis to tilt the carriage and hence the print head to adjust the spacing between the print head and the platen. The shoe is rotated by a gap change lever angularly movably supported on the carriage and having teeth for mesh with a gear mounted on the shoe. For initializing the spacing between the print head and the platen, the gear on the shoe is displaced out of mesh with the teeth of the gap change lever and rotated to turn the shoe. To achieve a desired spacing between the print head and the platen, the gear on the shoe is moved into mesh with the teeth of the gap change lever, and the gap change lever is turned to rotate the gear and the shoe for angular movement of the carriage.

The present printer is adapted to be easily equipped with removable and interchangeable paper feed modules of several different types. Each of the paper feed modules is specifically adapted to feed a particular type of paper through the printer and each is easily replaceable by the purchaser of the printer to be used for feeding a specific type of paper therethrough. The printer is provided with a main frame including a pair of side support members and an elongate platen extends between the side support members and is fixed at opposite ends thereto. Three different types of removable and interchangeable paper feed modules are illustrated in the present application and each includes a pair of elongated end plates with a paper moving mechanism supported intermediate the elongated end plates. The end plates are each provided with a pivoted mounting member adapted to engage a guide slot in the main frame side support members and a mounting notch is provided in the midportion of each of the end plates to swing into clamping engagement with the platen when the elongated end plates are pivoted about the pivotal axis of the mounting members so that the removable paper feed module may be inserted into the working region of the printer and on the side of the platen opposite the printhead and pivoted toward the printhead to bring the clamping notch into clamping engagement with the platen.

The present invention relates to a system for use in an ink-jet printer having a printhead and an opposing platen capable of movement toward and away from the printer's printhead to define a record media gap therebetween. The system is effective to selectively restrict movement of a printer's platen to effect adjustment of the record media gap upon detection of record media having a characteristic which warrants such a change. The system is provided with a detector capable of recognizing the characteristic, and with a stop mechanism which acts in concert with the detector to effect the desired change. In its nominal configuration, the stop mechanism limits movement of the platen at a first position so as to define a first record media gap. However, upon detection of record media having the characteristic, the stop mechanism is automatically reconfigured so as to allow movement of the platen to a second position defining a second record media gap.

A mechanism for compensating for different thicknesses of record media at a printing station utilizes a platen supporting or carrying assembly which is pivotable to move the platen toward the print head. Another supporting assembly, also pivotable, is provided to carry a record media drive roller and is interconnected with the platen supporting assembly by means of a pin and slot arrangement to effect a substantially equal gap at the platen-print head and at the pressure roller-drive roller. A first cam member is rotated to engage with and to swing the platen supporting assembly into printing position and a second cam member is connected with the first cam member and rotated thereby to maintain the assembly in printing position.