International Business Machines Corp. reported yesterday second-quarter earnings rose to $4.73 a share from $4.44 a share in the same period last year.

In the second quarter, IBM earned $691.23 million, compared with $658.3 million in the year-ago period. Revenues climbed to $4.92 billion from $4.42 billion.

For the first half, IBM's net income came to $1.28 billion ($8.74 a share) up from $1.23 billion ($8.26 a share) in the corresponding 1977 period. Revenues totaled $9.35 billion, against $8.51 billion.

Average shares outstanding during the first six months of 1978 were 146,442,166, down from 149,182,824 in the first half last year.

Frank T. Cary, chairman, said: "Purchases of data processing equipment were somewhat higher in the quarter and for the six months than in the comparable periods of 1977." He said this trend reflected a tapering off in demand for system-370 models 158 and 158 and increased shipments and purchases of new products.

"The world-wide buildup of resources to meet the strong demand for these new products, together with persistent inflationary pressures, continued to impact costs and expenses during the second quarter," Cary said.

"As a result, earnings for the quarter and six months show relatively modest gains over the comparable 1977 periods."

Gross income from the rentals and services was up 9.1 percent during the 1978 first half over the year-earlier period. Orders for data processing equipment were substantially higher than in the first six months last year.

IBM had a currency exchange gain of $22 million in the 1978 first half, consisting primarily of unrealized gains from the translation of foreign currency assets and liabilities.

Safeway Stores Inc. reported its earnings for the first 24 weeks of the year increased to $66.5 million ($2.55 per share) from $53 million ($2.04 per share).

The 25 percent increase in profits came as Safeway's sales grew 14 percent, from just over $5 billion to $5.7 billion for the period ending June 18. Since the prior year, Safeway had opened 45 new stores and closed 39 old ones, giving it a total of 2,434 at the end of the period.

Safeway reported sales for the latest 12 weeks increased to $2.9 billion from $2.5 billion and net income jumped to $41.3 million ($1.58 per share) from $30.4 million ($1.17 per share).

The Scripps-Howard Broadcasting Co. reported higher revenues and earnings for the latest three months and six-month periods.

For the three months ended June 30, Scripps-Howard earned $4.06 million or $1.58 a share on operating revenues of $17.39 million against $3.13 million or $1.21 on revenues of $12.99 million last year.

For the six months Scripps-Howard earned $6.8 million or $2.63 a share on revenues of $31.08 million compared to $5.3 million or $2.05 a share on revenues of $23.81 million a year earlier.