IBM Corp. unveiled four new models of typewriters this week and two enhanced models to create an integrated line that allows customers to purchase the cheapest model and continually upgrade to the most expensive.

"The IBM Wheelwriter II is a completely new family," IBM-Lexington General Manager Kailash C. Joshi told a news conference. "It offers the flexibility to our customers to upgrade as their needs grow."The line ranges from the IBM Personal Wheelwriter - which lists for a base price of $599 - to the top-of-the-line Wheelwriter 70 Series II, a menu-driven typewriter with word-processing that has a base price of $1,795.

"A customer's investment is protected because they can now migrate from the low end of the line to the high end," Joshi said. "All were designed and developed in our lab here in Kentucky and all will be manufac-tured at this facility."

The entirely new models are the Personal Wheelwriter and the Wheelwriter 30 Series II, the 50 Series II and the 70 Series II. Two existing models - the 3 Series II and 6 Series II - were enhanced so they could be upgraded to the 30, 50 and 70 models, Joshi said. The 10 Series II was unveiled in February.

The new Personal Wheelwriter is a replacement for IBM's Actionwriter 1, which is intended principally for use in schools, homes and small offices. Included in Wednesday's announcement was a cosmetic change in the IBM Quietwriter 8 to conform with the appearance of the Wheelwriter series.

The high-performance models unveiled this week - the 30, 50, and 70 Series II - all offer a spell-check system with a 120,000 word dictionary that alerts the operator to possible misspellings and offers alternative spellings.