Abstract: A ball forming apparatus free from parameter variations introduced in setting spark discharge control parameters wherein the variations may be largely of operator-dependent or apparatus-dependent nature. To control discharge parameters, digital data for controlling discharge are transmitted in serial communications from a wire bonder controller to the ball forming apparatus, and the digital data are used to set parameters such as discharge current, discharge time, heat development and the like. The discharge state data acquired during spark discharge is transmitted in serial communications from the ball forming apparatus to the wire bonder controller so that the above parameters are used for feedback control. Irregularity or difference in the ball size that may vary from apparatus to apparatus is eliminated, and an improved bondability results. Unnecessary bondings are reduced, and an improved manufacturing efficiency in semiconductor field is achieved.

Abstract: A method of forming a ball on the end of a wire by electrical discharge between the wire and an electrode includes detecting the discharge voltage and discharge current of an electrical discharge between an end of a wire having a diameter and an electrode; multiplying the discharge voltage by the discharge current for respective time intervals during the discharge to compute the heat energy supplied in the discharge during each time interval; integrating the heat energy for the time intervals during a discharge to determine the total heat energy supplied during the discharge; comparing the total heat energy with a predetermined heat energy that produces a ball on the end of the wire, the ball having a diameter of about two to three and one-half times the diameter of the wire; and controlling at least one of the discharge voltage, current, and duration in accordance with the comparison and terminating the discharge when the total heat energy supplied to the discharge exceeds the predetermined heat energy.

Abstract: A waterproof water-vapor-permeable laminated structure obtained by extrusion-laminating a thermoplastic resin layer on a porous base material. This laminated structure is free from pin holes and has a good waterproof property and a feeling of the porous base material. The thermoplastic resin layer to be employed in the laminated structure is selected to have a melt viscosity of 5.times.10.sup.4 poise (measurement conditions: load=10 kgf, nozzle diameter=1 mm, nozzle length=1 mm: JIS K 7311, 10) at a temperature lower than an extrusion temperature by 20.degree. C. The laminated structure is suitable for use as a medical waterproof fabric, an inner bag of a coverlet and the like products.

Abstract: A dot printer comprises a printing head, a memory, a first MPU for storing the dot-image data, corresponding to the input printing data, in the memory, and a second MPU for reading out the dot-image data from the memory, and supplying this data to the printing head, and for driving the printing head so as to effect a printing operation on the basis of the readout dot-image data. The dot printer additionally has first and second buffers, and its memory is connected to the first and second MPUs, via the first and second buffers, respectively.

Abstract: A thermal printer includes a CPU which reads out a corresponding character data from an ROM in accordance with a character specifying data from a host computer and selectively allows currents to flow through thermal resistors of a thermal head in accordance with the n-bit dot pattern data which constitutes the readout character data. A size data representative of the size of the picture element of the character to be printed is further generated from the host computer. The CPU converts the n-bit dot pattern data into the dot pattern data of the number of bits designated by the size data and selectively allows the currents to flow through the thermal resistors in accordance with this converted dot pattern data.

Abstract: In a thermal printer of this invention, a detector detects whether a ribbon cassette exists or not, and the thermal printer is automatically changed in thermal sensitive process or thermal transfer process by installing or detaching the ribbon cassette.