The present invention relates to an image reading device that reads information of an image photographed on a 35 mm standard negative film, and more particularly relates to an image reading device that reads information of an image photographed on a pseudo panoramic negative film. 
Recently, pseudo panoramic photographing has been conducted on a 35 mm standard negative film, or both standard photographing and pseudo panoramic photographing have been conducted with a 35 mm standard negative film.  Images on a negative film obtained by the pseudo panoramic photographing are printed, and also images on a standard negative film obtained by both the standard photographing and the pseudo panoramic photographing are printed.  When images obtained by the pseudo panoramic photographing are printed, it is necessary to cover the portions of the film on which the pseudo panoramic photographing has not been conducted. 
In order to cover the non-image portions of the film on which the pseudo panoramic photographing has not been conducted, it is necessary to read the pseudo panoramic photographed images on the film.  However, the aforementioned type image reading device has not been provided yet.  For example, the following image reading method can be easily devised.  In the method, the same panoramic adapter as that used for pseudo panoramic photographing is used so as to cover the non-image portions of the film on which the pseudo panoramic photographing has not been conducted. 
However, the standard of panoramic adapters has not been standardized yet, so that the dimensions and position of a panoramic adapter depend on the camera manufacturers.  Even when the same panoramic adapter is used for the same camera, there is a possibility that the position of an image photographed on a film is shifted due to the influence of the optical system and the shift of the film.  Therefore, it is difficult to completely remove the non-image portion by using a panoramic adapter. 
In the case where an image on a pseudo panoramic photographed image is read while the pseudo panoramic photographing negative film is set on a 35 mm conventional standard mount, even the unexposed non-image portion is subjected to image reading processing, so that the read portion is outputted into black.  Therefore, when the image is reproduced by a copier, black toner is wasted. 
Even if the panoramic adapter is standardized, in the case where both pseudo panoramic images and standard images are photographed on the same film, the following troublesome operations are required for an operator: in the case of a pseudo panoramic image, the panoramic adapter is inserted, and in the case of a standard image the panoramic adapter is removed. 
The present invention has been achieved to solve the aforementioned problems.  The first object of the present invention is to provide an image reading device capable of removing unnecessary portions except for a portion in which the pseudo panoramic photographing has been conducted, without using a panoramic adapter. 
In the case where printing is carried out using a pseudo panoramic photographing negative film, image information of the pseudo panoramic photographing negative film is read by an image reading device, and the obtained image information is subjected to image processing, and then the image information is outputted to a copier.  Before the aforementioned image processing, shading correction is carried out.  This shading correction is carried out in the following manner: a frame of the unexposed portion of the film or a corresponding filter is set in a film holder; and the film holder is inserted into a projector so that shading correction is conducted in accordance with the information of the unexposed portion. 
According to the aforementioned method, it is necessary to prepare an unexposed frame, the type of which is the same as that of the photographed negative film.  Therefore, the aforementioned method is not practical. 
However, unexposed frames tend to fade when they are preserved, and further they are susceptible to damage.  Therefore, when a shading operation is conducted with a faded unexposed film, the colors of the photographed negative film and those of the unexposed frame can not be balanced, so that color reproduction can not be accurately carried out. 
Pseudo panoramic photographing negative film has come into wide use recently.  However, image information is read and outputted by the same procedure as that of a conventional standard photographing negative film.  For example, in the case where exposure control data is taken in, there is no control method suitable for a pseudo panoramic photographing negative film, so that the conventional exposure control method has been used for the pseudo panoramic photographing negative film until now. 
The same method as that of a standard photographing negative film is applied to a pseudo panoramic photographing film.  Therefore, although a non-image portion exists on the film, a frame of another unexposed negative film is used separately from the photographed film.  Further, it is necessary to previously conduct a shading operation in addition to a reading operation. 
In addition, when the exposure control data is taken in, almost all the image portions of the standard photographing film are used as data in order to improve the accuracy.  In the case of a pseudo panoramic photographing negative film, the image portion is located only in the center of the frame.  Therefore, the same image range as that of the standard negative film is taken in for the pseudo panoramic photographing negative film.  For that reason, the density of the exposure control data becomes lower than that of an actual image.  After all, it is judged that the density of the pseudo panoramic photographing negative film is lower than that of an actual image, so that the exposure amount for the pseudo panoramic photographing negative film is reduced.  As a result, the obtained film is finished under exposure. 
The present invention has been achieved to solve the aforementioned conventional problems.  The second object of the present invention is to provide an image reading device by which excellent finished images can be obtain from a pseudo panoramic photographing negative film. 
The conventional image information reading of a pseudo panoramic photographing negative film is carried out as follows: a shading operation is conducted before image processing; exposure control is conducted; and then a reading operation is conducted.  Therefore, the image reading process is complicated and troublesome. 
In the case where image information of a pseudo panoramic photographing negative film is read a plurality of times, the shading data is collected at each time, or the shading data is collected for the first time, and the same data is used after that.  It is complicated to conduct the shading operation at each time as described above, and when the shading operation is conducted only once, it is impossible to maintain the image quality. 
In view of the aforementioned point, it is an object of the present invention to provide an image forming device by which image information can be easily read from a pseudo panoramic photographing negative film. 
The third object of present invention is to provide an image forming apparatus by which a predetermined image quality level can be maintained when a minimum shading correcting operation is conducted. 
Problems will be described as follows that are caused when the aforementioned conventional image reading device is applied to a copier. 
In order to directly print an image onto a photographic paper from a negative film, a high level of technique and special apparatus are required.  Therefore, it is difficult for amateurs to print easily. 
On the other hand, technique of a color copier has made a great advance recently, so that a color image recorded on a paper can be highly accurately copied. 
As a result of the foregoing, the following color-copier has been proposed recently (for example, Japanese Patent Application Open to Public Inspection No.  46646/1991): An image recorded on a film of various kinds is projected by a projector.  The projected image is photoelectrically read by an image reading device provided with a photoelectric transfer element such as a CCD sensor in a color copier so that an electrical image signal is obtained.  In accordance with the obtained electrical image signal, a color-copying operation is carried out. 
When an image recorded on a film is projected by a projector, the operations are carried out in the following manner: the film is mounted on the projector with a film carrier; the film is .irradiated with light; the optical path of the transmission light is changed by a mirror unit; the film image is projected onto a Fresnel lens on the platen of the color copier; and the film image projected on the Fresnel lens is electrically read by an electrophotographic transfer element such as a CCD sensor of the color copier.  The copy paper is selected and printing magnification is determined in accordance with the image that has been read in the aforementioned process. 
An object of the conventional image reading device used for the aforementioned projector is designed to project an image recorded on a 35 mm film that is the most popular among amateurs. 
As shown in FIG.  1, the aforementioned pseudo panoramic film to record a panoramic image on a 35 mm film is used in the following manner: the upper and lower portions of an ordinary frame, the size of which is 24 mm.times.36 mm, are shaded so that a horizontal image screen size (13 mm.times.36 mm) can be obtained. 
As described above, the size of a projected image on a pseudo panoramic film is extremely long from side to side, that is the length of a longitudinal side is very different from that of a lateral side compared with a standard 35 mm film.  Therefore, the fourth object of the present invention is to provide appropriately determine the paper size, printing magnification and printing position in accordance with a projected panoramic image.