  We present near- and mid-infrared (IR) photometric data of the Type Ibn
supernova (SN) 2006jc obtained with the United Kingdom Infrared Telescope
(UKIRT), the Gemini North Telescope, and the Spitzer Space Telescope between
days 86 and 493 post-explosion. We find that the IR behaviour of SN 2006jc can
be explained as a combination of IR echoes from two manifestations of
circumstellar material. The bulk of the near-IR emission arises from an IR echo
from newly-condensed dust in a cool dense shell (CDS) produced by the
interaction of the ejecta outward shock with a dense shell of circumstellar
material ejected by the progenitor in a luminous blue variable (LBV) like
outburst about two years prior to the SN explosion. The CDS dust mass reaches a
modest 3.0 x 10^(-4) M(solar) by day 230. While dust condensation within a CDS
formed behind the ejecta inward shock has been proposed before for one event
(SN 1998S), SN 2006jc is the first one showing evidence for dust condensation
in a CDS formed behind the ejecta outward shock in the circumstellar material.
At later epochs, a substantial and growing contribution to the IR fluxes arises
from an IR echo from pre-existing dust in the progenitor wind. The mass of the
pre-existing CSM dust is at least ~8 x 10^(-3) M(solar). This work therefore
adds to the evidence that mass-loss from the progenitors of core-collapse
supernovae could be a major source of dust in the universe. However, yet again,
we see no direct evidence that the explosion of a supernova produces anything
other than a very modest amount of dust.
