Nippon Sheet Glass Company, Limited

Koichiro Iki

Shuya Ogi

Tomitaka Takagi

Takashi Fukuzawa

Minoru Toyama

Masahide Wakisaka

Kiyotaka Sasaki

Disclosed is an image forming apparatus which provides an image of an excellent quality which has a less variation in resolution and suppressed linear irregularity. A rod lens array includes two rows of rod lenses stacked one on the other. An LED array is offset by a predetermined offset amount from a plane passing the median position between the first row of rod lenses and the second row of rod lenses. This structure can realize an LED printer head which reduces a variation in the resolution of the rod lens array, thereby suppressing linear irregularity, and can thus provide an image having an excellent quality.

Apparatus with offset light source for forming images on photosensitive surface

An optical write-in head for obtaining a clear image even in printing at a relatively high recording density without generating strip-like irregularities in most cases. The optical write-in head applies light carrying image information to a photosensitive substance. The optical write-in head includes an array light source having a plurality of dot light sources each of which selectively emits the light corresponding to the image information, and a lens array facing the array light source. The lens array has a plurality of lens elements which corresponds to the plurality of dot light sources respectively. An angular aperture &#x3b8; of each of the lens elements is set in a range of about 14&#xb0; to 18&#xb0;.

Optical write-in head, image forming apparatus using the same, and method for inspecting the apparatus

An aligning tool having a plurality of grooves formed side by side is provided; gradient index rod lenses are placed in alignment within the grooves at an average spacing of 1 &#x3bc;m-5 &#x3bc;m; the gradient index rod lenses are fixed to form an integral unit as they maintain the aligned state; thereafter the end faces of each rod lens are polished.

Rod lens array and a process for producing the same

An optical write-in head for obtaining a clear image even in printing at a relatively high recording density without generating strip-like irregularities in most cases. The optical write-in head applies light carrying image information to a photosensitive substance. The optical write-in head includes an array light source having a plurality of dot light sources, each of which selectively emits the light corresponding to the image information, and a lens array facing the array light source. The lens array has a plurality of lens elements which corresponds to the plurality of dot light sources respectively. An angular aperture &#x3b8; of each of the lens elements is set in a range of about 14&#xb0; to 18&#xb0;.

An aligning tool having a plurality of grooves formed side by side is provided; gradient index rod lenses are placed in alignment within the grooves at an average spacing of 1 &mgr;m-5 &mgr;m; the gradient index rod lenses are fixed to form an integral unit as they maintain the aligned state; thereafter the end faces of each rod lens are polished.

In an image forming apparatus, an object surface ( ) is disposed facing one end face of a rod lens array ( ), while an image surface ( ) is disposed facing the other end face thereof. A lens working distance of the rod lens array on the object side is substantially equal to that on the image side. An actual object-image distance Tco is set between the conjugate length TC1 at which the average value MTFave of the MTF of the rod lens array in the lens array direction is maximized and the conjugate length TC2 at which the &Dgr;MTF(&equals;(MTFmax&minus;MTFmin)/MTFave) is minimized, and a shift quantity &Dgr;TC(&equals;&verbar;TCo&minus;TC1&verbar;) is set within 0 mm<&Dgr;TC<&plus;02 mm for the conjugate length TC1 at which the MTFave is maximized.

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Osaka, Japan

Koichiro Iki