Abstract: An object of the present invention is to efficiently shape a light flux emitted from a light source into a linear shape and so as to provide an optical element having high versatility that can be widely used irrespective of the original sizes and to provide an illumination apparatus having such an illumination apparatus. The optical element has a reflection surface in the form of an inner side of a curved surface that is formed by rotating a parabola about a rotation axis including the focus of the parabola or a point near the focus of the parabola.

Abstract: A zoom lens comprises, from the object side to the image side, a first lens group, a second lens group, and a rear group including one or more lens groups, where the first and second lens groups can move at the time of zooming, and wherein the first lens group comprises, from the object side to the image side, a first lens of negative refractive power, and a second lens of positive refractive power.

Abstract: A zoom lens comprises, from the object side to the image side, a first lens group, a second lens group, and a rear group including one or more lens groups, where the first and second lens groups can move at the time of zooming, and wherein the first lens group comprises, from the object side to the image side, a first lens of negative refractive power, and a second lens of positive refractive power.

Abstract: In an apparatus including a unit which is recoverable and reusable after use, an environmental history indicator member having a property variable according to an environmental history of use of the apparatus and arranged not to participate in any functions of the apparatus during use of the apparatus is disposed inside the unit or adjacent to the unit. By checking the state of the environmental history indicator member when the unit is recovered from the apparatus after the end of service of the apparatus, a management system for reuse is arranged to easily and efficiently decide the unit to be reusable or no longer usable.

Abstract: A rod lens array to be used for an optical printer, including: (a) a plurality of rod lenses arranged in an array; (b) a substance filled between the plurality of rod lenses; and (c) a pair of substrates sandwiching the plurality of rod lenses and the substance, wherein each of the substrates comprises a panel member and a layer formed on the surface of the panel member bearing the rod lenses thereon, and wherein the panel member is made of a fiber-reinforced plastic material and the layer is made of a resin, and the layer eliminates undulations formed by the fibers in the panel member.

Abstract: A laminate-type diffractive optical element which is easily producible and which allows high optical performance to be easily achieved, and an optical system using the same, are disclosed. In the diffractive optical element formed by laminating a plurality of diffraction gratings, when the distance between the uppermost portion of one diffraction grating and the lowermost portion of the other diffraction grating in two diffraction gratings adjacent to each other along the incident direction of a light is represented by D (&mgr;m), these two diffraction gratings are arranged to satisfy the following relation: 10 &mgr;m<D<40 &mgr;m.

Abstract: An object-of the present invention is to efficiently shape a light flux emitted from a light source into a linear shape and so as to provide an optical element having high versatility that can be widely used irrespective of the original sizes and to provide an illumination apparatus having such an illumination apparatus. The optical element has a reflection surface in the form of an inner side of a curved surface that is formed by rotating a parabola about a rotation axis including the focus of the parabola or a point near the focus of the parabola.

Abstract: An ultraviolet-permeable resin is used for a substrate of a diffraction grating, and at least one grating portion formed from ultraviolet cured resin is provided onto a surface of the substrate, thereby alleviating performance deterioration that is caused by heat expansion and the like due to environmental changes and enabling a large angle of view and cost reduction due to the simple construction. Further, a diffractive optical element using the diffraction grating, and an optical system using the diffractive optical element, are also obtained.

Abstract: A rod lens array to be used for an optical printer comprises a plurality of rod lenses arranged densely in array, an opaque substance filled in the gaps separating the plurality of rod lenses, and a pair of side panels sandwiching the plurality of rod lenses and the opaque substance.

Abstract: A rod lens array to be used for an optical printer includes a plurality of rod lenses arranged densely in an array, an opaque substance filled in the gaps separating the plurality of rod lenses, and a pair of side panels sandwiching the plurality of rod lenses and the opaque substance. The rod lens array satisfies the requirement as defined by the formula: S<(Z/L)·(25.4/5P) where P is the resolution of the optical printer expressed in dpi, Z is the length of the rod lenses expressed in mm, L is the conjugate length of the rod lenses expressed in mm, and S is the flatness of the surfaces of the side panels bearing the rod lenses.

Abstract: An LED printer head capable of reducing influence of a sub emission band by use of a rod lens array and thus prevent light of the sub emission band from reaching a development level. The LED printer head consists of an LED array of LEDs to emit light according to an image signal, which are arrayed at the resolution pitch P of not less than 600 dpi, and a multi-lens array for forming an emission image of the LED array on a photosensitive body. Each of the LEDs of the LED array has a main emission band of an emission spectrum and another sub emission band having a peak level of not less than 0.01 as a photosensitive intensity ratio R to the main emission spectrum, and a difference D between best total conjugate lengths at peak wavelengths of the main and sub emission bands by the multi-lens array is at least 0.15.

Abstract: A rod lens array for optical printer head includes a plurality of rod lenses arranged cyclically in a predetermined direction. The rod lenses are fixed by filling a opaque substance into the gaps separating the respective rod lenses and sandwiching the rod lenses and the opaque substance with a pair of side panels. The side panels have a cyclical structure resulting in undulations at least on their surface facing the rod lenses, and the pitch of the beat generated by the cycle or arrangement of the plurality of rod lenses and the cyclical structure of the side panels is not greater that 0.6 mm or substantially infinite.

Abstract: A laminate-type diffractive optical element which is easily producible and which allows high optical performance to be easily achieved, and an optical system using the same, are disclosed. In the diffractive optical element formed by laminating a plurality of diffraction gratings, when the distance between the uppermost portion of one diffraction grating and the lowermost portion of the other diffraction grating in two diffraction gratings adjacent to each other along the incident direction of a light is represented by D (&mgr;m), these two diffraction gratings are arranged to satisfy the following relation: 10 &mgr;m<D<40 &mgr;m.

Abstract: In an apparatus including a unit which is recoverable and reusable after use, an environmental history indicator member having a property variable according to an environmental history of use of the apparatus and arranged not to participate in any functions of the apparatus during use of the apparatus is disposed inside the unit or adjacent to the unit. By checking the state of the environmental history indicator member when the unit is recovered from the apparatus after the end of service of the apparatus, a management system for reuse is arranged to easily and efficiently decide the unit to be reusable or no longer usable.

Abstract: An object is to provide an LED printer head in structure capable of reducing influence of a sub emission band by use of a rode lens array and thus prevent light of the sub emission band from reaching a development level, thereby achieving high quality to the contrary. The LED printer head consists of an LED array of LEDs to emit light according to an image signal, which are arrayed at the resolution pitch P of not less than 600 dpi, and a multi-lens array for forming an emission image of the LED array on a photosensitive body. Each of the LEDs of the LED array has a main emission band of an emission spectrum and another sub emission band having a peak level of not less than 0.01 as a photosensitive intensity ratio R to the main emission spectrum, and a difference D between best TCs at peak wavelengths of the main and sub emission bands by the multi-lens array is at least 0.15.

Abstract: An image forming apparatus which can obtain a high-quality image although the adjustment of alignment is easy or unnecessary is provided. In the apparatus, light beams emitted from light-source means, in which a plurality of light-emitting devices are arranged in a one-dimensional direction, are focused onto a surface of a recording medium by a lens array formed by arranging a plurality of condensing lenses in a scanning direction in two lines so as to staggerly and closely place lenses in one line on lenses in another line. When the radius of a field of view of a single condensing lens is represented by X.sub.0, the diameter of the condensing lens is represented by D, and a degree of overlap is represented by m=X.sub.0 /D, the lens array is formed so as to satisfy the following condition:1.85<m<2.00.

Abstract: A device for illuminating an original for use in an original reading apparatus for reading an original placed on an original supporting table has a light source having a filament having its lengthwise direction disposed so as to be perpendicular to a reading line.

Abstract: An Optical filter is provided on a light receiving surface of an image sensor. The filter has a plurality of thin layers alternately laminated. The thin layers alternately consist of a dielectric layer having a high refractive index and a metal layer and each thin layer has its stress .sigma. in a range -5 GPa.ltoreq..sigma.<-0.2 GPa.

Abstract: In an image reading apparatus, a first object and a second object are adapted to be illuminated on different regions each other with a light beam from a light source by an illuminating device. A first imaging optical system is provided to image image information of the first object on a single photoelectric converting device. A second imaging optical system is provided in an optical path different from that of the first imaging optical system so as to image image information of the second object onto the photoelectric converting device. The first and second object to be illuminated, and the photoelectric converting device are relatively displaced to read the image information of the first and second objects.

Abstract: An image reading lens that is constructed of, in succession from the object side, a stop, a meniscus-shaped positive first lens having its convex surface at the image plane side, and a negative second lens having its concave surface at the image plane side. Both the lens surfaces of the first lens and at least one lens surface of the second lens are constructed of an aspherical surface. The shape of the object side aspherical surface of the first lens is formed so as to be inside a reference spherical surface.