There are quite a few journals indexed in the Design and Applied Arts Index (DAAI) which can be accessed through ProQuest.
The International Review of Graphic Design is one other journal.
Gemser, et al. (2011) have surveyed the top industrial design journals by popularity and average ranking. They are not specifically dedicated to graphic design, but many sub-fields of "design" are interdisciplinary and you might find something there.
Otherwise you might try interational magazines rather than journals.
Gemser, G, Bont, C de, Hekkert, P & Friedman, K 2011, 'Quality perceptions of design journals: The design scholars’ perspective', Design Studies, vol. 33, no. 1. www.sciencedirect.com/science/article/pii/S0142694X1100069X