1. Field of the Invention
The present invention relates to an image reading device for reading an original document image, and more specifically relates to an image reading device capable of discriminating the direction of an original document image. The present invention further relates to an image forming apparatus provided with the image reading device.
2. Description of the Related Art
It has been proposed to provide in conventional image reading devices such as image readers, copying apparatus and the like, functions for discriminating the directional orientation of an original document image so as to improve operational characteristics relative to a user. In such an image reading device, the directional orientation of an .original document image is discriminated and said original document image is rotated to a normal directional orientation for output, such that a user sets the original document directly on the image reading device without necessarily being cognizant of the top and bottom of said original document.
For example, U.S. Pat. No. 5,077,811 discloses a device provided with functions for detecting the directional orientation of characters obtained by reading of an original document image by means of comparison with reference characters.
In the device of the aforesaid disclosure, the process of recognizing characters requires a long time due to the complexity of said process, and errors in detection may readily occur. The aforesaid device requires substantial memory for storing the aforesaid reference characters. Accordingly, a very large memory capacity must be provided in the case of character types having a large amount of characters such as in the Japanese language.
There are also image reading devices wherein directional orientation of an original document can be discriminated by discriminating the position of page numbers and headings appended to said original document. Although such image reading devices can reduce the processing time for discriminating the directional orientation of an original document image, they possess certain disadvantages inasmuch as the directional orientation of an original document cannot be discriminated when page numbers or headings are not present.