US 11,851,569 B2
Ink, image forming method, image forming apparatus, and printed matter
Tomohiro Hirade, Kanagawa (JP); Masaki Kudo, Kanagawa (JP); and Mio Akima, Tokyo (JP)
Assigned to RICOH COMPANY, LTD., Tokyo (JP)
Filed by RICOH COMPANY, LTD., Tokyo (JP)
Filed on Mar. 23, 2021, as Appl. No. 17/209,609.
Claims priority of application No. 2020-064003 (JP), filed on Mar. 31, 2020.
Prior Publication US 2021/0301156 A1, Sep. 30, 2021
Int. Cl. C09D 11/037 (2014.01); C09D 11/033 (2014.01); C08K 3/22 (2006.01); C08K 3/36 (2006.01); B41M 5/00 (2006.01)
CPC C09D 11/037 (2013.01) [B41M 5/0023 (2013.01); C08K 3/22 (2013.01); C08K 3/36 (2013.01); C09D 11/033 (2013.01); C08K 2003/2237 (2013.01)] 11 Claims
OG exemplary drawing
 
1. An ink, comprising:
water;
an organic solvent;
resin particles;
a first inorganic pigment; and
a second inorganic pigment,
wherein the first inorganic pigment comprises particulate titanium oxide, and the second inorganic pigment comprises at least one selected from the group consisting of acicular titanium oxide and fusiform titanium oxide,
wherein a mass ratio of an amount of the first inorganic pigment to an amount of the second inorganic pigment is 4 or more but 10 or less,
wherein the particulate titanium oxide has an aspect ratio of lower than 5,
wherein the fusiform titanium oxide has an aspect ratio of 5 or higher but lower than 10,
wherein the acicular titanium oxide has an aspect ratio of 10 or higher, and
wherein the aspect ratio is a ratio of an average major axis length to an average minor axis length.