From Africa Investor magazine’s May – August 2005 edition. (I’d link to this article about currency printing in Africa, titled “Paper Wealth,” by Neil Ford but it’s not available online). By his research, the top currency companies in Africa are:

1. De La Rue (UK) (45% of the African market)
2003 results: Sales 211 million pounds (banknotes and paper only)
Net income 30.4 million pounds – and dividend of 13.6 p per share
One of the biggest producers and suppliers of bank notes, printing 150 national currencies worldwide and has supplied notes to Africa since 1860 when it delivered notes to Mauritania. Has a production plant in Kenya and paid a dividend of Euros 23 million in 2004. The company plans to do better and is undergoing a restructuring that will see it dispose of non-core businesses to improve productivity.

2 Giesecke & Devrient (G&D) (35% of the African market)
2003 results: Sales (banknotes and paper only) Euros 588 million with Europe, Middle East and Africa business being Euros 479 million
Net income Euros 28.8 million
Is the 2nd largest private sector supplier of paper money in Africa, and printed four billion banknotes last year. Has secured contracts from Nigeria, Ghana, Rwanda, Tanzania, Kenya, and others and has an office in Cairo and operations in SA and Nigeria.

3. Francois-Charles Oberthur Fiduciaire (FCOF) (10% of the African market)
2003 results: Sales (banknotes and paper only) Euros 60 million
African business Euros 30 million
This French firm has activities in 70 countries worldwide but has achieved most of its success in Francophone Africa.

Other players are:
ANB (US)
The Canadian Bank Note Company
Crane (Sweden)
Enschede (Netherlands)
Orell Fuessli (Switzerland)

In summary, low production costs make Africa an attractive place to set up printing facilities.