subscriber; regular reader; admirer
Refers to someone who regularly reads a particular publication or author, often with appreciation. Can be used for magazine subscribers, devoted fans of a writer, or loyal readers of a column.
This magazine's regular readers are spread across the country.
He is an admirer of Haruki Murakami's works.
購読者 specifically means a paying subscriber, whereas 愛読者 emphasizes the reading habit and appreciation, not necessarily a paid subscription.
Compound of 愛 (love, affection) + 読 (read) + 者 (person). The term follows a standard Sino-Japanese word formation pattern.