Since the Marsberg glass factory Marsberg also needed more capital, the Driburg glass wholesaler Heinrich Ritzenhoff joined the company as a partner in December 1934. He has been the managing director since 1935 and fully acquires the company shares in December 1935. Over the years Heinrich Ritzenhoff was supported by his son Klaus in managing the company. The company had developed so well economically that in 1957 an additional processing company under the company name H. u. Kl. Ritzenhoff KG could be newly founded. This company dealt with the finishing of lighting glass. The demand for glass in all variations continued to increase, so that there was also another branch in the municipality of Essenthocould be founded. Only glasses for breweries and distilleries were refined here. In 1965 Heinrich Ritzenhoff, also in the municipality of Essentho, set up a fully automatic glass production facility for the production of drinking glass series. In addition to the classic tumbler production, this branch of the company quickly expanded its position and became the most important part of today's company. In 1969 the company boss Heinrich Ritzenhoff died, his son Klaus took over the sole management of the company. In 1974 he founded the Graphic Ritzenhoff, a printing company that produces ceramic decals for glass.