  The measurement of proton plus helium and all-particle energy spectra in the
range $20\,$ TeV to $5 \,$PeV and $80 \,$TeV to $5 \,$PeV respectively are
presented. Data taken by the ARGO-YBJ detector in the 2010 year have been
analyzed. The ARGO-YBJ experiment (Tibet, P. R. China) has been taking data for
more than five years by means of a full-coverage array of RPC detectors. The
discrimination between showers produced by light and heavy primaries has been
performed by looking at the lateral particle density close to the core region.
A Bayesian unfolding technique was therefore applied to the measured quantities
in order to evaluate the cosmic ray energy spectrum. The proton plus helium
spectrum clearly shows a bending at about $1 \,$PeV, while the all-particle
spectrum is consistent with previous observations.
