Method of manufacturing a head unit

A method of manufacturing a head unit with a plurality of head chips mounted to one base, comprising the steps of:

• forming the plurality of head chips, each of the head chips comprising adjacent cores defining a front face and side faces of each of the head chips, the front face including a curved surface having a vertex, a head gap Bo defined as a distance between the vertex of the curved surface and a joint between the cores, a gap depth GD defined as a depth of the joint between the cores measured from one of the side faces of each of the head chips, a value of Bo before grinding being referred to as Bo1 and a value of Bo after grinding being referred to as Bo2, a value of GD before grinding being referred to as GD1 and a value of GD after grinding being referred to as GD2, the difference between GD1 and GD2 being referred to as ΔGD;
• mounting the plurality of head chips to the one base so that the curved surfaces of the plurality of head chips are adjacent to each other, the head chips being mounted to the one base so as to have a relative height difference Y with respect to the one base, the relative height difference being defined as a difference in level between two adjacent head chips of the plurality of head chips in a direction orthogonal to a traveling direction of the head chips;
• grinding the curved surfaces of the front faces of the mounted plurality of head chips;
• determining a value Bo1′ for Bo1 that corresponds to a target value Bo2′ of Bo2 prior to the mounting and grinding steps, the value Bo1′ being determined through a relationship between Bo and GD that is determined with respect to a head unit having a predetermined head relative height value Y′, the target value Bo2′, and a predetermined value ΔGD′ of ΔGD;
• wherein the forming step includes forming the plurality of head chips so that each of the head chips has a value Bo that when mounted to the one base in the mounting step is substantially equal to the value Bo1′, and has a value Y when mounted in the mounting step that is substantially equal to the value Y′, and the grinding step includes grinding the curved surfaces of the plurality of head chips by an amount ΔGD substantially equal to ΔGD′.