Magnetic tape cassette apparatus having reduced azimuth error

A magnetic tape cassette apparatus comprising:

• a head mounting plate;
• a magnetic head unit carried on said plate, said unit comprising a recording and/or playback magnetic head having a cylindrically curved head face in which at least one air gap terminates;
• a head mount including two tape guides, arranged one to each side of the air gap in the direction of tape transport, said guides each having a cylindrically curved guide surface and a height limiter at an axial end of the guide surface, said height limiters adjoining the respective guide surfaces along a line through the two height limiters, said line being perpendicular to a plane through the air gap perpendicular to the head face at the air gap;
• and control means disposed at the other axial ends of the guide surfaces for guiding a lateral tape edge so as to cause the other lateral tape edge to be maintained in constant contact with the respective height limiter during tape transport;
• and
• means for transporting a magnetic tape past said magnetic head and over said tape guides,
• characterized in that said head mount, guides and control means are formed by a unitary plastic molding surrounding said head on at least three sides and permanently fixed to said head,
• said control means consist of an obliquely disposed control surface adjoining each of the respective guide surfaces arranged such that the distance from the control surface of the tape guide to the respective height limiter decreases in a direction toward the guide surface, and
• said control surface has a configuration arranged such that a line of intersection of the control surface with the guide surface is located in a plane which extends substantially perpendicular to the guide surface.

A magnetic head unit for use in a magnetic tape recording or playback apparatus, comprising a recording and/or playback magnetic head having a cylindrically curved head face in which at least one air gap terminates;

• a head mount within which said magnetic head is fixed;
• two tape guides, each tape guide having a cylindrical guide surface and a tape height limiter;
• said height limiters adjoining the respective guide surfaces along a line through the two height limiters, said line being perpendicular to a plane through the air gap perpendicular to the head face at the air gap;
• and control means for keeping a lateral edge of a tape being transported across said head face in constant contact with the height limiters,
• characterized in that said control means consist of an obliquely disposed control surface adjoining each of the respective guide surfaces, arranged such that the distance from the control surface of the tape guide to the respective height limiter decreases in a direction toward the guide surface;
• said control surface has a configuration arranged such that a line of intersection of the control surface with the guide surface is located in a plane which extends substantially perpendicular to the guide surface ;and in that said control surface, guide surfaces and height limiters form an