The invention relates to a device for holding a roll of paper, including an axle, a support arm, and a pivot bearing, which holds the support arm at one end and the axle at the other, as well as including a holder ring with an approximately radial slot, into which the axle is inserted, which is used to fix the roll of paper. Devices of this type are generally known. They are usually made of two approximately circularly bent sheet metal plates, which are arranged in a parallel fashion, one with the other, to form a base plate and a cover plate. In the center of the center plate is mounted the axle, which is attached in some way at the end of the roll of paper. The cover plate is attached, for example by screws, to the free end of the axle, and is provided with a central cylindrical pivot bearing on which is attached the support arm. The center plate is also attached, for example by screws, to the support arm and serves to attach the center plate to the base plate. One problem associated with known devices of the above-described type is that when used in a printing press the entire support arm, which is usually made of a hardened steel sheet, may deform permanently under heavy loads, which results in the entire roll of paper becoming deformed or wrinkled. For the purpose of ensuring the proper running of the roll of paper, one may often insert, inside the support arm, a cylindrical rod made of a slightly flexible material. The rod is inserted into the support arm and is held in place by a spring at the end thereof. This creates a form of compensation which permits the lateral deformation of the support arm in order to compensate for the changes in length caused by the roll of paper, the effect of the roll of paper being to cause the roll of paper to bulge, and the compensation taking place automatically. In recent times one has started using plastic materials in support arms which can withstand heavy loads. Even though the use of plastic has the advantage of a reduction in weight, thereby increasing the printing speed of a press, it has now become apparent that it is extremely difficult to hold the support arm in a position in which it is suitable to support the roll of paper. In view of the above, it would be advantageous to provide a device for holding a roll of paper which overcomes the above-described problem. It would also be advantageous to provide a device for holding a roll of paper with a plastic support arm that can support the roll of paper reliably and without deformation. In addition, it would be advantageous to provide a device for holding a roll of paper which is lighter in weight than known devices and which can be used in a printing press in a quick and reliable manner. Furthermore, it would be advantageous to provide a device for holding a roll of paper which has fewer parts than known devices of a similar type.