Design of a simple slitting unit based on razor blades to be added to an existing label finisher

We want to add a media slitter to an existing label finishing system. Label finishers are cutting contours from self adhesive papers and films. After the cutting and removing of the redundant parts of the film, the rest often has to be slitted into several slices to make narrow rolls of labels or stickers. This slitting can be done very simple by means of razor blades. The media to slit are very thin (simple papers and films), so there are no high forces to endure for the whole construction. We need a construction how to add such a feature to our existing product, so that we can manufacture this slitting device ourselves with reasonable efforts (sheet metal design, bending, laser cutting, welding. etc.) and by buying parts from companies like Misumi ([login to view URL]), Ganther ([login to view URL]) or the like. The construction can only be fixed to the rear side of the label finisher, so it has to be a single side construction. The slitter has to be positioned at the right end of the label finisher, the slitted rolls will run onto the upper right axis (see pictures) in a vertical style, because material is moving up. The slitter can feature an axis to hold the blades (up to 4 blades, on the left side of the media) and one or two axis with bearings to press the blades against on the right side of the media. It is possible to feed the media through the whole slitting unit manually in order to insert the media in the beginning, if it has a closed end on the free floating side. I added several ideas how the slitter can be done and can look like. For us it is important that it consists of simple parts, the are solid and stable. We will add the slitting unit to the finished product. That's why we need to know what holes and threads we need to make in the rear wall of the label finisher in order to mount the slitter properly.