Method of manufacturing thermal head
Both ends of a head substrate in a longitudinal direction warp in a direction away from a cross section of a print substrate (in the convex shape) when a sealing resin is cured. A central portion of the head substrate in a longitudinal direction warps in a direction away from the cross section of the print substrate (in the concave shape) when heating elements emit heat. A curing condition when curing the sealing resin is changed corresponding to the concave-shaped warpage occurring when the heating elements emit heat, such that the convex-shaped warpage of the head substrate occurring when the sealing resin is cured is offset by the concave-shaped warpage of the head substrate and thus the heating elements are arranged in a straight line when the heating elements emit heat at the time of printing.
1. A method of manufacturing a thermal head having a head substrate on which a plurality of heating elements is arranged in a longitudinal direction thereof, comprising:
mounting a control unit on a print substrate so as to control heat emission of the heating elements; and
covering the control unit, a cross section of the print substrate, and a cross section of the head substrate with a sealing resin;
wherein the print substrate and the head substrate are mounted on a head mounting, and both ends of the head substrate in a longitudinal direction are warped in a direction away from the cross section of the print substrate when the sealing resin is cured;
a central portion of the head substrate in a longitudinal direction is warped in a direction away from the cross section of the print substrate when the heating elements emit heat, and
a curing condition when curing the sealing resin is such that the convex-shaped warpage of the head substrate occurring when the sealing resin is cured is offset by the concave-shaped warpage of the head substrate when the heating elements emit heat.
2. The method according to claim 1 ,
wherein the curing condition of the sealing resin is obtained by changing at least one of a resin material, a coating amount, heating temperature, or heating time.
3. The method according to claim 2 ,
wherein the curing condition of the sealing resin is such that the amount of the concave-shaped warpage of the head substrate occurring when the sealing resin is cured is in a range of about 20 to about 60 μm.