Thermal printer having a structure for supporting a print head with a driver on its front surface

• US 4,896,977 A
• Filed: 03/09/1988
• Issued: 01/30/1990
• Est. Priority Date: 03/12/1987
• Status: Expired due to Term

• Current Assignee: Brother Kogyo Kabushiki Kaisha
• Original Assignee: Brother Kogyo Kabushiki Kaisha
• Inventors: Kinoshita, Naohisa, Takagi, Kazuhiko
• Primary Examiner(s): Wiecking, David A.
• Application Number:
  US07/165,973
• Time in Patent Office: 692 Days
• Field of Search: 400/120, 346/76 PH, 219/216 PH, 219/538, 219/539, 219/541, 219/543, 219/544
• US Class Current: 347/209
• CPC Class Codes: B41J 2/345 characterised by the arrangement of resistors or conductors

Abstract

A thermal printer for printing with a print head moved relative to and in contact with a recording medium, supported by a platen. The print head has a plurality of printing elements arranged on its front surface, in a direction intersecting a print line. The print head is supported by a support structure movably between printing and retracted positions. The support structure provides, at least when placed in the printing position, a wedge-shaped clearance between the front surface of the print head, and a plane tangent to the bearing surface of the platen. The wedge-shaped clearance increases with a distance from the printing elements in a direction parallel to the print line. The print head further has a head driver secured on its front surface such that the head driver is positioned within said wedge-shaped clearance. The head driver is electrically connected to the printing elements, for controlling energization of the printing elements.

Claims

1. A thermal printer wherein a printing operation is effected by a print head which is movable along a print line relative to a recording medium while the print head and the recording medium are held in contact with each other via a thermal print ribbon, comprising:

a platen having a bearing surface for supporting said recording medium, said bearing surface extending in a direction parallel to said print line;

said print head having a flat front surface which faces said recording medium supported by said platen, said flat front surface being a generally L-shaped surface including an upright portion having a length perpendicular to said print line, and a horizontal portion which extends horizontally from one of opposite ends of said upright portion, said length of said upright portion being greater than a width of said thermal print ribbon;

a plurality of printing elements which are arranged on said upright portion of said flat front surface of the print head, in a direction intersecting said print line;

head supporting means for supporting said print head movably between a printing position in which said printing elements contact said recording medium on said platen, and a retracted position in which said printing elements are spaced away from the recording medium, said head supporting means providing, at least in said printing position thereof, a wedgeshaped clearance between said flat front surface of said print head, and a plane tangent to said bearing surface of said platen, said wedge-shaped clearance increasing with a distance from said printing elements in said direction parallel to said print line; and

a head driver secured to said horizontal portion of said flat front surface of said print head such that said head driver is spaced from said printing elements in said direction parallel to said print line and thereby positioned within said wedge-shaped clearance, said head driver being electrically connected to said plurality of printing elements, for controlling energization of said printing elements.

2. A thermal printer according to claim 1, wherein said head supporting means supports said print head pivotally between said printing and retracted positions, about an axis which is perpendicular to said print line.

3. A thermal printer according to claim 1, wherein said head supporting means supports said print head pivotally between said printing and retracted positions, about an axis which is parallel to said print line.

4. A thermal printer according to claim 1, wherein each of said printing elements consists of a heat-generating element which generates heat responsive to an electric current applied thereto by said head driver.

5. A thermal printer according to claim 1, wherein said printing elements consist of printing electrodes which contact said recording medium via a thermal print ribbon which includes an ink layer and an electrically resistive layer, said printing electrodes being energized by said head driver, to apply an electric current to corresponding local areas of said electrically resistive layer.

6. A thermal printer according to claim 1, wherein said flat front surface of said print head has a printed wiring formed thereon for electrical connection of said printing elements and said head driver.

7. A thermal printer according to claim 1, further comprising a flexible cable which has a fixed end positioned at an end of said print head opposite to an end of said flat front surface on which said printing elements are secured, said flat front surface of the print head has a printed wiring formed thereon for electrical connection of said head driver and said flexible cable.