A gradient-index (GRIN) array is used as an imaging unit in light-emitting diode (LED) printers. In this study, we measure tilts of GRINs in an array and analyze the intensity distribution of the image to clarify the tilting amount and to evaluate the relation between the GRIN tilt and the degradation of the image. The arrangement intervals of the GRINs are measured, and the GRIN tilts are calculated from the differences between the arrangement intervals of the surfaces on one side and the other side. In our previous study, we show from ray matrix analysis that the images obtained using accurately arranged GRINs are superposed on a single image. However, images obtained using tilted GRINs are not superposed on a single image resulting in the image degradation. Measuring the tilt of the GRIN in the array is useful for improving the image. The upper limit on the tilt of the GRINs in the array for the LED printer is evaluated from a symmetric property of the image.

梯度折射率（GRIN）阵列用作发光二极管（LED）打印机中的成像单元。在这项研究中，我们测量阵列中GRIN的倾斜度，并分析图像的强度分布以弄清倾斜量，并评估GRIN倾斜度与图像退化之间的关系。测量GRIN的布置间隔，并且根据一侧和另一侧上的表面的布置间隔之间的差来计算GRIN倾斜。在我们以前的研究中，我们从射线矩阵分析表明，使用精确排列的GRIN获得的图像叠加在单个图像上。但是，使用倾斜的GRIN获得的图像不会叠加在单个图像上，从而导致图像质量下降。测量阵列中GRIN的倾斜度对于改善图像很有用。