pyqtgraph：如何在00:00之前不显示时间序列（使用AxisItem）

how can I display time axis starting from 00:00 and do not display time axises before 00:00? Graph will display real time data read from sersor. And it will start plotting the data at the very right side of the graph starting from 00:00(time when data is arrived) and will slide to the left as data arrives. So I want to get rid of the time-axis values before 00:00? I appreciate all your suggestions.how can I display time axis starting from 00:00