SCIENCE/TECHNOLOGY

Gradco Stake: Martin E. Tash has increased his state in Gradco Systems Inc. in Irvine to 14.8%, or 1.1 million shares, according to a filing with the Securities and Exchange Commission.

The purchase were made during the first nine months of 1991 by Tash, his wife, Arlene, and the New York publishing company he owns, Plenum Publishing Corp. They purchased 139,530 shares of Gradco stock for prices ranging from $2.625 to $4.25 a share, which would mean the recent purchases totaled between $366,000 and $593,000.

Gradco stock closed Monday at $2.875, down 25 cents in over-the-counter trading.

At the company’s annual meeting on Oct. 17, Tash said he plans to ratify the previously announced sale of Gradco’s copier products business to the company’s Gradco (Japan) Ltd. subsidiary.

Plenum and Tash said they expect to increase their stake in Gradco in the future.