Are SG7100DN and SG3110DN Print Heads The Same?

[UK Printed Mugs]

Would anyone know if the print heads on the Ricohs A4/A3 (3110 and 7100) are the same and only the body of the printer is different? We have an issue with uni-directional printing on the 7100 and want to know if we can swap with print head from 3110. Thanks.