A treatment protocol by which a renal stone patient is administered a chelating agent, generally once a day and preferably by mouth, during a treatment phase and is later administered the same chelating agent once a week, during a \u201cmaintenance\u201d phase. The color image formation apparatus forms only images of color pages, and then an user sets the color pages in an inserter. A first voltage source supplies a higher voltage than a second voltage source. The adjustment of the spring system is such that a greater degree of hardness corresponds to a higher position of the upper edge regions of the side reinforcements. Prioritizing the requests may be accomplished by computing a target deadline for a request based on a monitored arrival time of the request and a target latency for its workload.