A multi-color-liquid-toner electronic photograph printer, comprising: electronic-photograph-printing units for printing images on a web; a density sensor for measuring densities of images printed by the electronic-photograph-printing units at a plurality of points in a width direction of the web at downstream in the feeding direction of the web relative to the electronic-photograph-printing units; a density-measurement section for moving the density sensor in the width direction of the web; and a density controller section for comparing an average value for the densities of the images measured by the density sensor with preset reference density values, and for causing the densities of images which are about to be printed on the web by the electronic-photograph-printing units to coincide with the reference density values, wherein one of the electronic-photograph-printing units prints a band-shaped density-controlling patch (51, 52, 53,54) extending in the width direction of the web, the density-measurement section controls the densities of images which are about to be printed on the web by the electronic-photograph-printing units in accordance with the densities of the density-controlling patches (51, 52, 53,54) measured by the density sensor at the plurality of points in the width direction of the web, the density sensor moves in the width direction of a web linearly and the position of a movement line of the density sensor in the density-measurement section is fixed in the electronic photograph printer, the alignment between the density-controlling patches (51, 52, 53,54) and the density sensor are ensured by the feeding movement of the web, the reference density value is set for each color, each color of the density-controlling patch (51, 52, 53, 54) is printed so that the density-controlling patches (51, 52, 53, 54) are shifted with respect to the longitudinal direction of the web, the density sensor measures the density of each color of the corresponding density-controlling patch (51, 52, 53, 54) at the plurality of points in the width direction of the web, and the density controller section compares the average value of the densities of the images measured by the density sensor with preset reference density values and controls the density of each color which is about to be printed on the web by the corresponding electronic-photograph-printing unit whereby the average value of the densities of images which are about to be printed coincides with the reference density value; characterized in that, the electronic photograph printer further comprises a sensor-movement-control section that controls driving states of a sensor-moving mechanism included in the density-measurement section, the density-measurement section is capable of setting a plurality of image-density-measurement points, at which the density sensor suspends its sensing movement, at the plurality of points in the width direction of the web in accordance with an instruction put into the sensor-movement-control section, and the density-measurement section moves the density sensor in the width direction of the web while ensuring that the density sensor suspends its sensing movement for a preset suspension time at each image-density-measurement point in a state that the alignment between the density-controlling patches printed on the web and the density sensor is ensured in the feeding direction of the web. electronic-photograph-printing units for printing images on a web; a density sensor for measuring densities of images printed by the electronic-photograph-printing units at a plurality of points in a width direction of the web at downstream in the feeding direction of the web relative to the electronic-photograph-printing units; a density-measurement section for moving the density sensor in the width direction of the web; and a density controller section for comparing an average value for the densities of the images measured by the density sensor with preset reference density values, and for causing the densities of images which are about to be printed on the web by the electronic-photograph-printing units to coincide with the reference density values, wherein one of the electronic-photograph-printing units prints a band-shaped density-controlling patch (51, 52, 53,54) extending in the width direction of the web, the density-measurement section controls the densities of images which are about to be printed on the web by the electronic-photograph-printing units in accordance with the densities of the density-controlling patches (51, 52, 53,54) measured by the density sensor at the plurality of points in the width direction of the web, the density sensor moves in the width direction of a web linearly and the position of a movement line of the density sensor in the density-measurement section is fixed in the electronic photograph printer, the alignment between the density-controlling patches (51, 52, 53,54) and the density sensor are ensured by the feeding movement of the web, the reference density value is set for each color, each color of the density-controlling patch (51, 52, 53, 54) is printed so that the density-controlling patches (51, 52, 53, 54) are shifted with respect to the longitudinal direction of the web, the density sensor measures the density of each color of the corresponding density-controlling patch (51, 52, 53, 54) at the plurality of points in the width direction of the web, and