In the screenshot we can see that some other fonts (outside the chart) are also blurred – text saying “Please select”. Hence am not sure if the issue related to CanvasJS library itself. Please answer below questions so that we can further investigate the problem.
In which version of IE did you take the screenshot?
Are you emulating IE8 rendering via IE11/IE10??
Can you check if the page has been “Zoomed” in IE?? If yes, please reset the IE zoom level and try again.