Appeal 2007-1855
Application 10/815,650
The dielectric loss tangent (tan δ) of the toner is preferably from
0.001 to 0.01, more preferably from 0.002 to 0.006, from the
viewpoint of the printed image quality, especially the
background fogging, which is affected by the dispersibility of
the charcoal powder in the toner. . . . The tan δ of the toner can
be adjusted by changing the kinds, the amounts and the pre-
mixing time of the raw materials, various conditions in the
kneading step, and the like.
Id. 11:23 to 12:7.
With respect to Specification Table 1, Examples 1, 3, and 4 are
prepared with “KA-2 (Shirasagi KA-2): coconut shell-based activated
carbon, commercially available from TAKEDA CHEMICAL
INDUSTRIES, LTD,” that has a D50 of 3.81 µm and a CV of 60.3%, and the
toners have a BG (background fogging) of 0.37 µm, 0.31 µm, and 0.61 µm,
respectively, and “good” “thin-line reproducibility;” Example 2 is prepared
with “YP-17: coconut shell-based activated carbon, commercially available
from KURARAY CHEMICAL CO., LTD,” that has a D50 of 5.16 µm and a
CV of 59.9%, and the toner has a BG of 0.50 and “good” “thin-line
reproducibility;” and Comparative Examples 1 and 2 are prepared from two
different commercial wood-based activated carbons having a D50 of 5.59 µm
and 20 µm, respectively, and a CV of 88.2% and 78.3%, respectively, and
the toners have a BG of 1.19 and 0.81 and “poor” “thin-line reproducibility
(Specification 22). The Specification reports the results show “the toners of
Examples 1 to 4 have low occurrences of background fogging and excellent
thin-line reproducibility, so that the image quality is excellent . . . [and]
sufficient degree of blackness and covering strength are obtained” (id.).
We find no evidence in the Specification that the commercial
activated carbon products were modified by pulverization to obtain the
stated D50 and CV values.
11
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