Abstract: A head drive mechanism capable of improving color shading in an exposed image due to a variation or nonuniformity in speed of a photosensitive head corresponding to pitches of teeth of a toothed belt. The photosensitive head includes a dot block which is constituted by a luminous dot group constituted of a line of a row A formed of even luminous dots and a line of a row B formed of odd luminous dots. Also, the rows A and B are so arranged that the luminous dots of the row A and those of the row B are offset from each other with an interval Ds being defined therebetween. A final transmission system is constituted of a toothed drive pulley, a toothed driven pulley and a toothed belt. The toothed belt is constructed so as to have tooth pitches Q=2Ds/(2n+1) reduced in terms of a relative travel distance of the head, wherein n is 0 or a positive integer.

Abstract: A carriage moving mechanism includes a carriage movably mounted on a guide shaft, a travelling motor fixedly mounted on the carriage, the travelling motor including a pinion mounted on a rotary shaft thereof, a rack provided in substantially parallel to the guide shaft, the rack being rigid longitudinally and flexible in a perpendicular direction to the longitudinal direction, the rack having longitudinally a tooth part engaged with the pinion, the surface of the rack located on the opposite side of the surface of the tooth part being substantially parallel to the guide shaft, a roller rotatably mounted on the carriage, the roller radially facing to the pinion and making contact with the opposite side surface to the tooth surface of the rack, the rack being rotatably mounted on the frame in one end thereof and restricted by the frame in the other end thereof in the extent of moving thereof or directly fixed on the frame in the other end thereof.

Abstract: A toy simulating a typewriter for enabling a child to compose a large number of sentences from a limited number of words, the toy having a keyboard with a plurality of keys, each key having a word imprinted thereon. A carriage is provided with paper receiving imprints of the words from hinged type arms operable upon depression of the keys, depression of one of the keys performing the imprinting operation and release of the key actuating a spacer frame coacting with an indexing bar for incrementing the carriage under force of a spring a predetermined distance.