The present invention relates to an image generating device, more particularly, to an image generating device for an electrophotographic copying machine wherein a separation belt peels the toner image transferred copying paper from the photoreceptor.
Any conventional image generating device which generates a toner image on a copying paper needs to reliably peel the toner-image-received copying paper from the photoreceptor. To achieve this, a prior art device provides means for peeling the toner-image-received copying paper in the form of a separation charger, while another prior art device provides means for peeling the toner-image-received copying paper from the photoreceptor in the form of a separation belt.
In particular, the latter device provides means for preventing a toner image from being generated at the position where the separation belt comes into contact with the photoreceptor by directing light reflected from a white-color reflection plate onto the edge of the surface of the photoreceptor. When operating the system mentioned above, since the portion of the original document obscured from illuminating light by the white-color reflection plate is imaged on the surface of the photoreceptor, this portion eventually causes the appearance of black streaks.
To solve this problem, one of the prior art devices provides means for allowing some of the illuminating light from the light source to be radiated onto the original document, despite the presence of the reflection plate, to cause the majority of the illuminating light to be reflected by the reflection plate. More particularly, Japanese Laid-Open Patent Application No. 10160/1982 discloses, in its FIG. 9, a system having a small hole at a specific position in the reflection plate for allowing illuminating light to pass through this hole. This prior art device also discloses provision of a reflection plate composed of a material allowing a specific amount of illuminating light to pass through it. In addition, this prior art device provides an arrangement with specific angles related to the installation of the mirror-surface reflection plate and edge cutoff angle within the surface which is perpendicular to the original document, and in addition, it includes a pair of luminous bodies. Details of these are shown in FIGS. 11 through 14 of Japanese Laid-Open Patent Application No. 10160/1982.
Of these image-generating devices described above, the device allowing a portion of the illuminating light to pass through the reflection plate prevents noticeable black streaks. On the other hand, if a negligible amount of light passes through the reflection plate, the device cannot effectively prevent the generation of black streaks. Conversely, if an excessive amount of light passes through the reflection plate, there will not be a sufficient cancellation of the charge present in the portion where the separation belt comes into contact with the edge of the photoreceptor surface. The latter image generating device depending upon the installation angle of the mirror-surface reflection plate, the cut-off angle of the edge and the pair of luminous bodies requires high-precision in the installation and cutoff operations. With less precision, the device cannot sufficiently prevent black streaks from being generated, and, it cannot thoroughly eliminate charge from the photoreceptor.