A monitor showing the logo of Mitsubishi Materials Corp is seen in Tokyo Thomson Reuters TOKYO (Reuters) - Japan's Mitsubishi Materials Corp <5711.T> said it has found more cases of products shipped with possible falsified specifications as it investigates a widening data-fabrication scandal that has affected more than 300 of its customers.

The revelation is among the latest in a slew of scandals to rock Japan's manufacturing industry. Similar lapses have been seen at Kobe Steel <5406.T> and Toray Industries Inc <3402.T>, and incorrect final inspection procedures have been found at automakers Nissan <7201.T> and Subaru <7270.T>.

Mitsubishi Materials said on Tuesday that its unit, Mitsubishi Cable Industries Ltd [MTCBL.UL], shipped magnetic wires with possibly fabricated data to five customers, and that it was checking on the safety and performance of the products.

Mitsubishi Materials had said last month that the same unit had inappropriately distorted data for rubber sealing products, used in aircraft and cars.

While no safety issues have been identified in the earlier cases, the company has said customers in Japan, the United States, China and Taiwan may have received affected products.

Mitsubishi Materials President Akira Takeuchi said the firm in its ongoing investigation into the matter had not found any evidence to suggest senior executives knew of the failings.

"I do not think there were instances of infraction of compliance issues based on instructions from headquarters," Takeuchi said.

Mitsubishi Cable Industries President Nobuhiro Takayanagi said it did not currently look like it would be necessary to expand the probe beyond the past year being investigated.

"Even if the investigation period had expanded, it's unlikely we would see much more new additional cases," Takayanagi said. "That is a guess taking into account that products sold and the customers remain roughly the same."

The company said it would not be able to finish the investigation by year-end, but would aim to issue a report on the causes of the scandal and the measures to prevent the recurrence as soon as possible.

Mitsubishi Materials' general manager, Nobuyuki Suzuki, said the company has not received any calls for replacements from customers or any notice that lawsuits had been filed against it.

Earlier in the day, Hitachi Ltd <6501.T> said it had installed more than 10,000 elevators that did not meet specifications it had submitted to the government, but added that there were no safety concerns with the elevators.

Also this week, Japanese authorities raided the offices of construction firms for suspected collusion over contracts for an $80 billion high speed train line.

Fretting about the impact from the string of falsification and compliance scandals, nearly half of Japan's firms have taken steps to strengthen internal controls or are planning to do so, a Reuters poll showed earlier this month.

(Reporting by Osamu Tsukimori; Writing by Aaron Sheldrick; Editing by Tom Hogue)