Improvement of a lower cylinder of a drum assembly for a helical scan type magnetic recording/reproducing apparatus, a magnetic tape being wrapped around the drum assembly in a predetermined angular range with respect to its own axis which is wider than a scanning angular range so as to have an additional tape-wrapping angular range on at least a tape-entry portion from which the tape starts to be wrapped around the drum assembly. The lower cylinder integrally has on its outer circumferential surface a tape-guiding portion for guiding the tape on wrapping it around the drum assembly, a tape-wrapping portion on which the magentic tape is wrapped along the tape-guiding portion in a direction substantially coincident with a direction of rotation of the upper cylinder and a protruding portion formed in the additional tape-wrapping angular range so as to be protruded by a predetermined amount with respect to the tape-wrapping portion. The protruding portion initially comes into contact with the tape to be entered onto the drum assembly and has a wedge-like shape in which its top is substantially directed in the tape-travelling direction. The protruding amount of the protruding portion with respect to the tape-wrapping portion being substantially equal to a protruding amount of the magnetic head from an upper cylinder of the drum assembly.
A method for manufacturing a drum assembly for an internal drum-type imaging apparatus, and a drum assembly produced using the method. The drum assembly defines an imaging surface which is at least semi-cylindrical. A drum skin defines an imaging surface, and is releasably wrapped around a cylindrical mandrel, which has an axis. The mandrel and wrapped drum skin have a first radius. A drum includes more than one drum portion, and is attached to the drum skin over an at least semi-cylindrical interface. The drum has a radius slightly greater than the first radius, and the drum and attached drum skin cooperate to define a vacuum chamber. A fluid bearing is generated between the drum skin and the mandrel, preferably by pressurizing the vacuum chamber, in order to separate the drum skin from the mandrel. The drum and attached drum skin are then moved relative to the mandrel and in a direction parallel to the axis to remove the drum assembly from the mandrel. The drum and drum skin provide an imaging surface that is greater than semi-cylindrical.
A rotary-head drum device for use in a video tape recorder or the like includes a fixed drum and a rotatable drum rotatably mounted on the fixed drum. Magnetic heads are mounted on the rotatable drum for sliding contact with a magnetic tape guided around the fixed drum and the rotatable drum. The fixed drum has an air outlet defined as a recess therein near a tape exit point where the magnetic tape leaves the fixed drum and the rotatable drum, for ejecting air against the magnetic tape to keep the magnetic tape in good contact with the magnetic heads near the tape exit point.
A rotary head drum having at least one stabilizer installed in a magnetic tape recording and/or reproducing apparatus is described, in which at least one stabilizer is provided to bring about the stability of the traveling of a tape which travels while in contact with the circumferential surface of a drum. The stabilizer has a circular plane of a predetermined diameter, and the circular plane is mounted in a lower fixed drum to be partially in contact with the tape, thereby rotating with the tape at the same linear velocity. The tape only slightly vibrates while traveling in contact with the stabilizer, and travels with stability. Noise due to jitter, wow and flutter caused by the tape vibration is eliminated in the picture and sound. This rotary head drum is utilized in a video cassette recorder, digital audio tape recorder, etc.
Magnetic recording/reproducing apparatus has a lower drum, an upper drum equipped with a rotary magnetic head and being coaxially and rotatably supported by the lower drum, a first tilt driving device for tilting a center axis of the upper and lower drums at a predetermined angle to allow a rotary locus of the rotary magnetic head to coincide with a recorded track on a magnetic tape, a lead ring having a first tape positional regulation surface for guiding a reference edge of the magnetic tape, the lead ring being independently provided close to an outer peripheral surface of a small diameter section of the lower drum, and a second tilt driving device for tilting the lead ring to allow the first tape positional regulation surface thereof to match the reference edge of the magnetic tape. The apparatus has a constructive feature that a second tape positional regulation surface is at least provided at an end of a tape contacting area in a tape inlet side of the lower drum for guiding the reference edge of the magnetic tape running at the highest magnification speed in a trick play reproduction mode with respect to a tape speed of a normal recording.
A recording or reproducing apparatus has a rotary head drum which is composed of a rotary drum with magnetic heads mounted on the outer periphery thereof and a stationary drum. It records a signal on or reproduces a signal from a magnetic tape by running the magnetic tape which is pulled around the predetermined portion of the outer peripheral surface of the rotary head drum. An angle varying member for varying the angle formed between the magnetic tape and the rotary head drum is provided at least at one of the locations where the magnetic tape enters and leaves the rotary head drum. Alternatively, a member for positioning the magnetic tape relative to the rotary head drum may be provided.
