(19)
(11) EP 0 659 574 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
03.04.1996 Bulletin 1996/14

(43) Date of publication A2:
28.06.1995 Bulletin 1995/26

(21) Application number: 94309820.2

(22) Date of filing: 23.12.1994
(51) International Patent Classification (IPC)6: B41J 25/304, B41J 11/20, B41J 25/316, B41J 2/155
(84) Designated Contracting States:
FR IT

(30) Priority: 27.12.1993 JP 333587/93

(71) Applicant: SEIKO INSTRUMENTS INC.
Chiba-shi, Chiba 261 (JP)

(72) Inventors:
  • Onuki, Hideki, c/o Seiko Instruments Inc.
    Chiba-shi, Chiba (JP)
  • Sato, Katsuari, c/o Seiko Instruments Inc.
    Chiba-shi, Chiba (JP)
  • Konuma, Satoru, c/o Seiko Instruments Inc.
    Chiba-shi, Chiba (JP)

(74) Representative: Sturt, Clifford Mark et al
J. MILLER & CO. 34 Bedford Row, Holborn
London WC1R 4JH
London WC1R 4JH (GB)


(56) References cited: : 
   
       


    (54) Printer


    (57) In a line printer, a rotation shaft (9) of a platen (2) is utilized as a fulcrum of a head-up lever (4). The head-up lever (4) and a bearingof the platen (2) are made in an integral form. As a result, the total number of parts of the line printer can be reduced and total number of assembling steps can also be reduced. Positioning of a print head (3) with respect to the platen (2) is achieved by establishing a precise engagement between a first pin (20) integrally formed on the edge portion of the print head (3) and a first guide groove (18) formed on a side wall (7,8) of a frame. As a consequence, the correct positioning of the print head can be performed with respect to the platen (2). On the other hand, a second pin (21) of the print head is journalled under a floating condition by a scond guide groove (19) of the side (7,8) wall of the frame (1). This second pin (21) functions as a free fulcrum when the pressure contact of the print head (3) is released. As described above, play is formed at the free fulcrum of the head-up lever, so that distortion of parts and machining tolerance can be accommodated. Since the energizing force given to the print head (3) is performed by employing only one elastic member (14) around a centre of the platen (2) in the lengthwise direction, a so-called floating effect may be produced and eccentric abutting of the print head (3) and platen (2) can be avoided. The print head (3) is detachably assembled to the frame (1). The assembled print head (3) is held by a rear plate (12) which is similarly detachably engaged with the frame (1). The elastic member (14) is integrally assembled into the print head (2) together with the lock lever (17). As a result, the print head (3) can be simply assembled and can be easily replaced. Since the lock lever (17) is provided in order that the rear plate (12) is not easily accidentally removed, it is more possible that the print head is prevented from being dismounted when this is not desired.






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