The former head of the federal agency that prints U.S. currency was charged in an indictment yesterday with giving favorable treatment to a New York printing firm that later hired him.

James A. Conlon, 57, former director of the Bureau of Engraving and Printing, was charged with one count of conflict of interest and three counts of lying to the federal grand jury here that indicted him.

His former assistant director at the bureau, Richard C. Sennett, 52, also was indicted separately on similar charges.

Conlon is accused in the indictment of "unlawfully and knowingly" supporting a federal contract with the American Bank Note Co. for an anticounterfeiting system to be used for U.S. currency when, at the same time, he had an arrangement concerning a future job with the private firm.

Conlon resigned as director of the bureau in mid-1977, and was made president of an American Bank Note subsidiary one day later, according to previously reported information from the Senate Permanent Subcommittee on Investigations.

The Senate panel also said Conlon may have helped American Bank Note get "abnormally high" profits on $130 million worth of food stamp printing contracts, but no mention of that allegation was contained in the criminal charges filed yesterday.

The conflict-of-interest charge carries a possible maximum penalty of two years in prison, a $10,000 fine, or both.

Each of the charges of making false declarations to the grand jury carries a possible maximum penalty of five years in jail, or a $10,000 fine, or both.

The perjury charges concern Conlon's denials to the grand jury that he supported the firm in its contract dealings with the bureau and his further assertion that his decision to retire was "spontaneous."

The grand jury charged that Conlon knew well in advance he was leaving the bureau when he did and that he had long planned to go to the firm.

Senate investigators had charged, for example, that Conlon helped the company find office space eight months before he retired and was offered a job by the firm at that time.

In an appearance before the Senate panel in May, Conlon heatedly denied any conflict of interest and said he was the victin of overzealous investigators.

"My relationship with the American Bank Note Co. and other private sector firms, and my activities as an employe and director of the Bureau of Engraving and Printing, were not only free of any impropriety, but were motivated by, and predicated on, the best interests of the government and the bureau, and, they, in fact, contributed significantly and substantially to those best interests." Conlon told the Senate subcommittee.

He said he had no need to get involved in a conflict of interest because "I was confident I would have no difficulty obtaining employment upon my retirement on the merits of my record..." Conlon could not be reached for further comment last night.

The contract with which he reportedly was involved concerned a proposed "security signature system" marketed by American Bank Note Co., which was a special treatment of currency paper so counterfeit bills could be more easily detected. Conlon told the grand jury he had nothing to do with that contract proposal, according to the indictment.

Sennett, former assistant director of the bureau who is now vice president of engineering for ABN Development Corp., a subsidiary of American Bank Note, was charged with participating in discussions, before leaving the bureau, concerning the modification of presses leased from American Bank Note. The indictment alleged that he knew at the time he was going to work for the private firm.

For example, he reportedly opposed returning the presses to American Bank Note as suggested by other bureau employes, but did not tell other bureau employes he intended to go to work for the firm, the indictment alleged.

Sennett denied the conflict-of-interest charge in an interview with the Associated Press last night, saying, "I have no problem with having the opportunity to defend myself on that."

He also denied the perjury charges, adding, "That's a shocker to me. I've told the truth all my life."

The bureau, at 14th and C Streets SW, prints money, stamps, food stamps, and other official government documents.

Conlon started at the bureau in 1942 as an apprentice plate printer, and won numerous awards during his career at the Treasury Department, of which the bureau is a part.