This is an opaque projector (Wikipedia). The image of the illuminated photo print, postcard, painting, etc., is projected through the lens to the projection screen. A slightly different geometry, for greater magnification, is used to project art onto screens or walls for tracing or copying the image. Artigraph is a brand of these copying opaque projectors.
According to the Wikipedia article, projectors used to be divided into two classes: diascopes, where light shines through transparent slides; and episcopes, where light reflects off opaque prints. Thus, opaque reflectors are also known as an episcopes.
Episcopic projection is much less efficient (i.e., requires a more powerful light source) than diascopic slide/transparency projection. And because the power of light sources directly corresponds to the heat produced by them (especially with the pure incandescent or flame generated light used back in the day), and the need to protect the opaque image from the generated heat, this limited the usefulness of episcopic projectors. For equivalent power light sources, opaque projectors were dimmer than slide projectors, and therefore could not accomodate larger screens so large numbers of people could view them without being too dim.
The site Luikerwaal.com is dedicated to Magic Lanterns (Wikipedia), with lots great examples, including several episcopes and epidiascopes (convertible, able to show opaque or transparent sources). Interestingly, they have an image of an old advertisement for a "post card magic lantern", suggesting that at the time of the ad, all projectors were types of magic lanterns.
Advertisement for a "post card magic lantern", from Luikerwaal.com