1. Field of the Invention
The present invention relates to an image forming apparatus such as a copying machine, a printer or a facsimile apparatus and to an image forming apparatus having the functions of these apparatuses.
2. Description of the Related Art
Recently, there has been proposed an image forming apparatus such as a copying machine, a printer or a facsimile apparatus, as well as image forming apparatus having the functions of these apparatuses, which uses a so-called flat bed type original tray and a stationary optical system as the reading means.
Regarding such an image forming apparatus, there have been proposed various types of sheet conveying paths for conveying a sheet to the image forming section and for discharging it to the exterior of the apparatus. For example, FIG. 10 is a side sectional view which shows an image forming apparatus 100 serving as a copying machine.
The image forming apparatus comprises an image forming section including a reader section 102 provided above a casing 101 and adapted to optically scan an original image and read it to generate image information, a laser scanner unit 103 provided below the reader section 102 and adapted to reproduce the original image on a sheet P in accordance with the image information of the original generated in the reader section 102, a process cartridge 105, and a fuser 106. A sheet supporting section 114 is arranged on the rear side of the apparatus main body (the right hand side in FIG. 10) and is adapted to support a plurality of sheets P, such as copying paper. The apparatus further comprises a manual sheet supply section 113 for manually supplying sheets P one by one, a sheet feeding mechanism 104 equipped with a feeding roller 104a for feeding the sheets P supplied from the sheet supporting section 114 or the manual sheet supply section 113 to the process cartridge 105, and sheet conveying means consisting of various rollers for conveying the sheets P.
In the image forming apparatus 100, the sheets P supplied from the sheet supporting section 114 or the manual sheet supply section 113 are separated and fed one by one by the sheet feeding mechanism 104 at the bottom, and supplied to the process cartridge 105, where a toner image formed by the process cartridge 105 is transferred to the sheet.
After this, the image is supplied to the fuser 106, where the toner image is fixed to complete the image forming process, and then the sheet with the image is discharged to the exterior of the apparatus by the pair of rollers of the sheet discharge section 115.
This image forming apparatus 100, in which the sheet conveying path is short, provides various advantages. For example, the time for copying the first sheet can be shortened, jamming does not easily occur, a reduction in the size of the apparatus is possible, and the apparatus is inexpensive.
In the image forming apparatus 100 shown in FIG. 10, the sheet supporting section 114 supports the sheets P in an inclined position, and holds substantially the central portion of the sheets, so that it is difficult to supply a large number of sheets. Further, dirt is liable to adhere to the sheets P, and dust is liable to accumulated thereon.
In addition, in the image forming apparatus 100, all of the means for supplying the sheets P, namely the sheet supporting section 114 and the manual sheet supply section 113, are provided on the rear side of the apparatus, so that depending upon the apparatus installation condition, the supplying of the sheets P may be difficult.
Thus, it is required of this image forming apparatus 100 to make it possible to supply a large quantity of sheets, to provide additional sheet supplying means on the front side of the apparatus, etc. More specifically, it might be possible, for example, to add to the front side of the apparatus a cassette feeding mechanism using a sheet loading cassette capable of supplying a large quantity of sheets.
FIG. 11 shows an example in which, while maintaining the basic construction of the image forming apparatus of FIG. 10, a sheet loading cassette (hereinafter simply referred to as a sheet cassette) 107 is attached to the bottom front portion of the apparatus main body, and a sheet feeding mechanism is provided from the sheet cassette 107. The components which are the same as those shown in FIG. 10 are indicated by the same reference numerals.
In this image forming apparatus 200 shown in FIG. 11, there is a sheet feeding path 108 from the downstream side of the cassette 107 to the image forming section, and the sheets fed from the downstream side of the sheet cassette 107 are caused to make a U turn at the sheet feeding path 108 and conveyed to the process cartridge 105.
The sheet cassette 107 is capable of loading and accommodating a large number of sheets, and is attached to casing 101A such that the loaded sheets are substantially horizontal. Further, the sheet cassette 107 is equipped with a cover 107a for preventing dust and other contaminants from adhering to the loaded sheets.
Due to this arrangement, in the image forming apparatus 200, sheet feeding by way of two sheet feeding paths in two directions is realized. Further, the arrangement provides the following advantages: the time for copying the first sheet can be shortened, jamming does not easily occur, etc. At the same time, it is possible to supply a large number of sheets to the sheet cassette 107 and to prevent dirt, dust and other contaminants from adhering to the sheets loaded in the sheet cassette 107.
However, in the image forming apparatus 200 shown in FIG. 11, it is necessary to join the sheet feeding paths from the two directions. Further, it is necessary to add a pair of rollers 109 in order to prevent a deterioration in conveying power due to the rounding of the sheet feeding path 108 from the sheet cassette 107. Thus, as is apparent from comparison with FIG. 10, the length of the sheet feeding path from the sheet feeding mechanism 104 to the process cartridge 105 increases.
As a result, in the image forming apparatus 200, the depth of the casing 101A increases, the size of the entire apparatus increases, and the installation area increases. Further, since the sheet feeding path 108 from the cassette 107 is situated considerably deep in the apparatus, jam processing for removing a jammed sheet when it occurs is not easy to perform.
To cope with the above problem, a construction has been proposed in which a door is provided on the right or left-hand side of the casing 101A and in which this door is opened to take in or out the process cartridge 105. However, this involves an increase in the area occupied by the apparatus in use, so that it is actually necessary to secure a wide space for the installation of the apparatus, which is not desirable.
The present invention has been made in view of the above problems. It is accordingly an object of the present invention to provide an image forming apparatus which is equipped with a sheet supporting means with satisfactory operability and which can be reduced in size while shortening the time for forming the first image, reducing jam generation and achieving a reduction in cost. More specifically, there is provided, in accordance with the present invention, image forming apparatus comprising an image reading means for reading an image on an original, image forming means for forming an image from image information read by said image reading means, and a sheet feeding means for feeding sheets to said image forming means, said sheet feeding means comprising a sheet supporting portion for supporting sheets on which images are to be formed and a feeding portion for feeding the sheets supported in the sheet supporting portion to the image forming means and arranged between the image reading means and the image forming means.
Further objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.