The present invention relates to a correction tape useful for making shadowless clean copies from original documents or drawings corrected by covering an area to be corrected or modified with a piece of paper, for example, a thin paper such as a plain paper or a relatively thick paper with a thickness of 1 mm to 2 mm, or other duplicating masters corrected in the same manner, and, more particularly, to a correction tape used for covering the periphery of of the paper put onto the area to be corrected in the originals or duplicating masters, thereby providing clean copies free of shadows would otherwise appear along the periphery of the patched paper when copying.
Further, this invention relates to a shadowless tape useful for correction or modification of letters or drawings in which the correction tape is put onto the portions to be corrected or modified in original documents or drawings and correction or modification is made on the tape. In making copies of originals or duplicating masters thus corrected, since the shadow of the correction tape does not appear in the copies, the corrected portions can no longer be detected in the copies and thereby clear copies can be obtained. Heretofore, when correction or modification is required in original documents or drawings, a different paper having an appropriate size is patched onto the portions to be corrected or modified and correction or modification is made on the paper. However, in making copies from the originals corrected in such a manner, using a copying machine, unfavorable shadows or dark lines are unavoidably formed in the resulting copies due to the difference in thickness between the patched portion and the other portion.
In order to eliminate such problems, for example, a correction tape, as shown in FIG. 4, has been proposed by the inventor of the present invention, the correction tape comprising a transparent base tape 1, a white opaque layer 4 coated on the central part of the base tape 1 and an adhesive layer 2 on the opaque layer 4. Although this correction tape can eliminate the shadow or dark line appearing in a copy due to the difference in thickness, it is particularly very difficult to form the opaque layer 4 with a sufficient thickness to completely cover up corrected or modified portions of the originals or masters, because the opaque layer 4 becomes more susceptible to cracking and delamination due to bending or the like with increase in the thickness thereof. Therefore, it is highly desirable to develop correction tape which can make correction or modification of the original indistinguishable in making copies and provide copies free of the shadow or dark lines.