The invention relates to a device called a rotating head which is used to deform the edge of the points or nibs of ball-point pens. The compounds include at least one phosphonate group covalently attached at any site. Thus, level variation of the drive current IL which represents the superposition of the DC and high-frequency can be suppressed. In particular four different configurations of interconnections are shown and described. Virtual scan patterns in either mode can change within or between frames. The improvement using the simple statistical adaptive-filter controller is accomplished by optimizing a joint control of an echo canceller and a postfilter.