Abstract: A serial printer having a platen (5) and a carriage (4) having a printer head (6) with a plurality of aligned print needles close to the platen (5) for mosaic printing is disclosed. According to the present invention, an ink ribbon is in a detachable ribbon cartridge (3) under tension, and the printer head (6) has a smooth slope at the top of the head (5) that slopes towards the platen, thus, when the ribbon cartridge is put on the printer, the ink ribbon is temporarily twisted at the top of the slope on the head (6), and by swinging the printer head (5) a few times along the platen (6), the ink ribbon (1) at the top of the slope slides down along the slope into the narrow gap between the head (6) and the platen (6), and thus, the ink ribbon (1) is positioned in front of the print needles.

Abstract: A printer head having a circular first yoke, a cylindrical permanent magnet fixed on the circular first yoke, a (n) number of electromagnets (n is an integer) positioned on a circle on the first yoke within the permanent magnet having predetermined angle intervals, a ring shaped second yoke fixed on the permanent magnet so that the upper surface of the second yoke is on the same plane as that of the upper surface of the electromagnets, a ring shaped spacer positioned on the second yoke, a disk shaped spring fixed on the spacer having a common outer ring and a (n) number of projections projected in the internal direction from the common outer ring, (n) number of armatures each fixed on each projection of the spring, (n) number of print needles each fixed to each armature so that a print needle is perpendicular to the plane of the spring, a circular yoke plate fixed on the spring having (n) number of radial slits for accepting the armatures and the width of each slit being narrower than the width of projection

Abstract: A serial printer head is provided which comprises a sandwich structure (1,3,5) of a first circular yoke plate (1), a cylindrical magnet (3) and a ring shaped second yoke plate (5); a plurality of electromagnets (2,4) positioned on the first yoke plate (1) at predetermined angle intervals; an armature-print-needle assembly (7,8,9,10) having a circular resilient spring (7), a plurality of armatures (8) and a plurality of print needles (9) placed on the sandwich structure (1,3,5) so that the sandwich structure (1,3,5), electromagnets (2,4) and the armatures (8) provide first a substantially closed magnetic path; and an adjusting yoke (12) attached to the sandwich structure (1,3,5). The adjusting yoke (12) has the magnetic characteristics that the magnetic reluctance increases as the temperature increases. Although the flux generated by the permanent magnet (3) is changed due to the change of the temperature, that flux change is compensated for by the presence of the adjusting yoke (12).

Abstract: A printer head for mosaic printing having a plurality of needles positioned on a straight line each being selectively driven towards a paper through an ink ribbon has been found. The printer head comprises of a cylindrical permanent magnet, a first yoke covering the bottom of the permanent magnet, a plurality of electromagnets each positioned on a circle on the first yoke with the predetermined angle intervals, a disk shaped spring having an outer ring and a plurality of projections towards the center of the disk, a plurality of armatures each attached to the related projection of the disk spring, a plurality of print needles each attached to the related projection of the disk spring so that each of the needles has the perpendicular component to the disk spring plane.

Abstract: A small printer is provided which comprises a housing, a rolled printing paper mounted in the housing, a platen along which a paper runs, a motor, and a carriage having a printing head for mosaic printing on a paper on the platen. The carriage travels along the whole width of the paper and is driven by the motor, and a paper transfer mechanism transfers the paper by one line for every traverse of the carriage. The paper transfer mechanism comprises an idler positioned beneath the path of the paper, the idler being swingable in the moving direction of the paper, and the idler having a first projection parallel to the path of the carriage at the left half of the idler and a second projection inclined to the path of the carriage at the right half thereof. The projections are engaged with the corresponding slots provided at the bottom of the carriage to ensure the swing movement of the idler is synchronized with the movement of the carriage.