A digital phase-locked loop and a digital phase-frequency detector thereof are provided. A energy transmitting cartridge is mounted in the second passageway. A back cut separates a first layer into unequal segment lengths. Further, the discriminative appearance model component may have been trained to estimate a score function that minimizes the angle between a gradient direction and a vector pointing toward a ground-truth shape parameter. In a network comprising a plurality of image output devices having different levels of image displaying quality according to purposes for which the displayed images are used, the image signals having been read from the storage device are capable of being quickly transferred or outputted according to purposes for which the displayed images are used. The plurality of ink supply cartridges include at least one black ink supply cartridge which supplies black colored ink to a black ink color channel of the printhead.