An apparatus for producing printed products includes a processing device in which respectively one cover is attached to a spine of a book block. The back plate assembly includes a body and a roller. Disclosed is a high-molecular weight conjugate of a steroid, comprising a structure in which a carboxylic acid group of a polymer having a polyethylene glycol moiety and a succinic acid monoamide moiety having two or more succinic acid monoamide units is ester-bonded to a hydroxy group in the steroid. The bit profile is cross-correlated with bit profiles of documents in the search space to identify candidates for a detailed matching stage. The bogie of the present invention solves the technical problem that the deformation of the damping springs keeps constant whether a car is empty or loaded in the prior art, and thus improves the damping effect of the bogie.