JPS5893086A - Electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To obtain a clear copy of an original containing a color which is so far hard to regenerate, by providing plural photoreceptors of different spectral sensitivity characteristics and then selecting a desired photoreceptor in accordance with the original. CONSTITUTION:In case an original containing a red color is reproduced, the 1st photoreceptor 2A is set at a prescribed position and then electrified 7, exposed 8 to light and developed 13. Then a toner image is transcribed on a transfer paper 17 and then fixed at a fixing part 19. After the transcription, the photoreceptor 2A is used again through the cleaning 20. In the case of the reproduction of a blue original, a photoreceptor 2B is selected to perform an exactly same procedure as that for the above-mentioned red original.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a plurality of photoreceptors having different spectral sensitivity characteristics,
This relates to an electrophotographic copying machine that uses different photoreceptors depending on the document.

As a photoreceptor for a general copying machine, it is desirable that its spectral sensitivity corresponds to a luminous sensitivity curve. However, the spectral sensitivity characteristics of a photoreceptor have a unique curve, and for example, with a photoreceptor that is highly sensitive to blue, it is difficult to copy blue characters (for example, digital copy, carbon paper original, etc.). Similarly (,
With a photoconductor having high sensitivity to red, red characters (for example, vermilion) are difficult to copy.

SUMMARY OF THE INVENTION Therefore, the present invention provides an electrophotographic copying machine that is provided with a plurality of photoreceptors having different spectral sensitivity characteristics, and selectively uses them depending on the original to obtain a desired copy. Hereinafter, embodiments will be described in detail with reference to the drawings.

Conventionally, there are copying machines equipped with multiple photoconductors, but all of these photoconductors are the same photoconductor (with the same spectral sensitivity characteristics).
Therefore, it does not meet the purpose of the present invention.

FIG. 1 shows an embodiment of the present invention, in which numeral 1 denotes a photoreceptor support belt, on which a sheet-shaped first photoreceptor 2A and a second photoreceptor 2B having different spectral sensitivity characteristics are arranged. It is. This photoreceptor support belt 1 is stretched by rollers 3, 4 and 5, and is configured to circulate in the direction of arrow C by driving a motor 6 connected to the rollers 3. 7
8 is a charger that uniformly charges the two photoconductors or 2B; 8 is a scanner that moves in the direction of the arrow;
, and the reflected light is imaged on a stationary photoreceptor through the focusing imaging element 12 to form an electrostatic latent image.

A developing section 13 attaches toner to the electrostatic latent image formed on the photoreceptor to visualize it. 14 is a transfer charger,
The toner image on the photoreceptor is transferred onto a transfer paper 17 fed out from a paper cassette 15 by a paper feed roller 16. In the case of printing, the registration roller 18 aligns and feeds the transfer paper so that the leading edge of the transfer paper coincides with the leading edge of the image on the photoreceptor. A fixing section 19 fixes the toner image transferred to the transfer paper, after which the copy paper is discharged.

A cleaning device 20 cleans the surface of the photoreceptor after the toner image has been transferred, in preparation for the next copying operation.

The two first photoreceptors and the second photoreceptor 2B exhibit spectral sensitivity characteristics as shown in FIG. 2, for example.

The two photoreceptors have a maximum sensitivity in the short wavelength region □, which is more sensitive to blue than □, so it is difficult to obtain copies of the same color. Further, the photoreceptor 2B has maximum sensitivity in a long wavelength region, and red color does not easily appear.

Next, the operation of this embodiment will be explained. Now, when a red original is to be reproduced, the first photoreceptor 2A is used. first,
By selecting a switch or button (not shown), the two first photoreceptors are placed at the positions shown in FIG.

Next, the roller 3 is rotated in the direction of the arrow by the drive of the motor 6, and the two photoreceptors pass under the charger 7 from the tip to the top at a constant speed and are uniformly charged. The two photoreceptors whose entire length has been charged come to a predetermined position (the position of photoreceptor 2B in FIG. 1) and stop. Subsequently, the scanner 8 moves to the left, scans the document surface, and projects the document image onto the two photoreceptors. When the scanner 8 completes scanning the original, the motor 6 resumes driving, the two photoreceptors move in the direction of arrow C, the image is developed by the developing section 13, and the scanner 8 moves to the right and returns to the original position. Return to position. The developed toner images on the two photoreceptors are transferred to a transfer factory 17 and fixed in a fixing section 19. On the other hand, the photoreceptor A passes through the cleaning device 20 to have its surface cleaned, comes to the position shown in FIG. 1 again and stops, and the copying operation is completed.

Incidentally, when obtaining a plurality of copies of the same original, the two photoreceptors are charged by the charger 7 after cleaning, and the above copying operation is repeated.

In this embodiment, the focusing imaging element 12 is used to project the original image onto the photoreceptor, but an optical system combining a plurality of reflecting mirrors and lenses may also be used. .

When it is desired to reproduce a blue original, the photoreceptor 2B is selected in the same manner as described above, and the photoreceptor 2B is set in the position of the photoreceptor 2A in FIG. 1, and then the copying operation is performed.

When switching photoreceptors, the overall sensitivity usually differs. Therefore, in this embodiment, an exposure amount correction means is required for proper exposure for each photoreceptor.The scanning speed of the scanner 8 is changed in conjunction with the selection of the photoreceptor, and the exposure amount is corrected. It has become. In addition, the amount of light emitted from the exposure lamp may be changed, or the slit width may be mechanically changed in cases where a lens system is used.

As explained above, according to the present invention, a plurality of photoreceptors with different spectral sensitivity characteristics are provided, and the required photoreceptor can be selected according to the document, which is difficult to reproduce in the past. This has the advantage that clear copies can be obtained even for color originals, and copy quality can be improved.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an embodiment of the present invention, and Fig. 2 is a block diagram of an embodiment of the present invention.
FIG. 2 is a diagram showing the spectral sensitivity characteristics of two different photoreceptors. 1...Photoreceptor support belt, 2A...
......First photoconductor, 2B...Second photoconductor, 7...Charger,
8・・・・・・・・・Scanner, 10・・・・・・
...Original, 13...Development section, 14...
......Transfer charger, 19...
・Fixing section, 20...Cleaning, device 0゛

Claims (1)

[Claims] (1) Spectral sensitivity characteristics - different types of photoreceptors,
An electrophotographic copying machine comprising means for selecting one of the photoreceptors depending on a document. (2) The electronic device according to claim (1), wherein the means for selecting the photoreceptor includes means for correcting the exposure amount so that the selected photoreceptor is properly exposed. Photocopy machine.