JPS60666B2 - Copy machine - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in copying machines.

Conventionally, in an electrophotographic copying machine, an electrostatic image is formed every time one copy is made, or every time a certain number of copies are made, and a fixed number of copies are obtained from one electrostatic image, which is repeated. A method has been proposed in which a desired number of copies can be obtained.

In such an electrophotographic copying machine, for example, as shown in FIG. 1, the constant number of copies is 1 and the desired number of copies is 12.
In the case of a woman, a static latent image is formed at the start of copying and at the end of one line of copying. However, since the potential of the static latent image decreases in proportion to the number of times it is repeatedly used, the density and resolution of the copied image are better for the 10th copy than for the 1st and 11th copies. The more the electrostatic tank image is repeatedly used, the more the quality of the copied image deteriorates, and the more uneven the quality of the copied image becomes. Also, the manuscript can be replaced with the next manuscript after the final static latent image is formed, but the fewer copies are made after the final static latent image is formed, the less time there is to replace the original. Time may be lost and total copying time increases. SUMMARY OF THE INVENTION It is an object of the present invention to provide a copying machine that can eliminate the above-mentioned drawbacks, reduce unevenness in the quality of copied images, provide more time for replacing originals, and shorten the total copying time.

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, a document is placed on the document table 21, and the number Np of the document to be copied is set in the preset counter 22. As shown in FIGS.

The storage device 23 stores the use of the electrostatic image NM. When the print switch is pressed, the photoreceptor 24 is rotated. During the first rotation, this photoreceptor 24 is uniformly charged by a charging device 25, and an original image is exposed by an exposure device 26 to form a static exposure latent image. . The exposure device 26 consists of a slit exposure device using a lamp 27, mirrors 28 to 30, and an in-mirror lens 31. During operation, the lamp 27 is turned on by the first control device 32 to illuminate the original on the original stripe table 21. At the same time, the document table 21 is driven, and the document image is slit-exposed onto the photoreceptor 24 via the mirrors 28 to 30 and the mirror lens 31. Next, the photoreceptor 24 is developed by a developing device 33, and the image is transferred by a transfer device 35 onto a photographic paper fed from a paper feeding device 34.
After the transfer, the transfer paper is conveyed by a conveyance device 36, fixed by a fixing device 37, and discharged onto a paper discharge tray 38 as a copy. The transfer device 35 transfers the transfer paper to the photoreceptor 24 using a roller 39.
The surface of the roller 39 is charged to a predetermined potential of the same polarity as the surface potential of the photoreceptor 24 by a charging device 401 before the transfer position, and after the transfer position. On the side, the charge is removed by a corona charger 41 and cleaned by a cleaning device 42. On the other hand, a discharge lamp 43 serves as a device for cleaning the photoreceptor 24, and a cleaning device 44 removes residual toner.
, a corona charger 45 for static elimination is used, but at this time it is disabled by the first control device 32. Next, after the second rotation of the photoconductor 24, the electrostatic latent image forming device consisting of the charging device 25 and the exposure device 26 is disabled by the first control device 32, and the electrostatic latent image forming operation on the photoconductor 24 is performed. The static latent image formed on the photoreceptor 24 during the first rotation is used to perform copying. That is, the photoreceptor 24
Every time the photoreceptor 24 rotates once, the electrostatic latent image on the photoreceptor 24 is developed by the developing device 33 and transferred by the transfer device 35 to the transfer paper fed from the paper feeder 34, and the transfer paper is transferred to the fixing device. The image is fixed at 37 and discharged onto a paper discharge table 38. The preset counter 22 counts every time one copy is completed, and when it reaches the set number of copies Np, it sends a signal to the first control device 32 to end the copying operation. The comparison calculation device 46 detects the formation timing of the electrostatic latent image from the output signals of the preset counter 22 and the storage device 23, and based on the output, the first control device 32 turns on the static elimination lamp 43, After operating the cleaning device 44 and the static eliminating corona charger 45 to clean the photoconductor 24, the charging device 25 and the exposure device 26 are operated to clean the photoconductor 24.
Forms a latent image of Seiryu on top. When the electrostatic latent image is erased every time it is used for the number of times NM stored in the storage device 23 and a new one is formed, and the set number of copies Np is made, the number of times the electrostatic tank image is formed during copying is calculated. If nEx, the comparator 46 calculates the formation timing of the electrostatic latent image such that the electrostatic latent image is formed during copying the same number of times n8x, and the number of copies from each electrostatic latent image is approximately equal. Detect. That is, the comparison calculation device 46 performs the calculation NEX=n; and issues an instruction to the first control device 32 so that the static latent image is formed every time NEx copies are made. Therefore {1}
If NM>Np, the electrostatic latent image is formed only at the start of copying, but not during copying.

■If NM<NP, then M, a static latent image is formed once during copying when field X=horse.

For example, as shown in Figure 4, if Np = 12 and NM = 10, NEX = hair: 6, and when the 6th copy is completed,
An electrostatic latent image is formed. Therefore, the copies with the lowest image quality are the 6th and 12th copies, and there is little difference in image quality between the 1st and 7th copies. Legs are M<NP style N
This is an EX method, and a static latent image is formed twice during copying.

For example, if NM=10 and Np=25, NEX=take=
83, and NM' becomes 8 or 9 pieces. [41 (N
;1〉mother<NP<nN If there is a cape, NEX 211 M=Misaki Saitai Sanren Shizo n8× becomes 4 only for that setting, and nE×nikasu=8.8
So NEx' becomes 8 or 9 pieces.

The first control device 32 receives instructions and instructions from the comparison calculation device 46. 1' The charging device 25, the exposure device 26, the static eliminating lamp 43, the cleaning device 44, the static eliminating corona charger 45, etc. are controlled as described above by signals from the set counter 22, print switch, etc., and the set number of copies Np is made. When the process is completed, the static elimination lamp 43 and the cleaning device 4 are turned off.
4. After operating the charge eliminating corona charger 45 to clean the photoreceptor 24, the copying operation is ended.

Further, the second control device 47 lights up the display 48 after the final static fog latent image is formed to indicate that it is OK to replace the document, or activates the automatic document feeder, based on the signal from the comparison calculation device 46. . In this case, since the number of copies to be made from each electrostatic latent image is approximately the same, the number of copies after the last electrostatic latent image is formed will not be extremely small, and there will be time for exchanging originals, reducing time loss. This reduces the total copying time. As described above, according to the copying machine according to the present invention, since the number of times each electrostatic latent image is used is roughly controlled, the number of times each electrostatic latent image is used can be minimized, thereby reducing unevenness in the quality of copied images. This allows more time to exchange originals and shortens the total copying time.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining a conventional electrophotographic copying machine, FIGS. 2 and 3 are a schematic front view and block diagram showing an embodiment of the present invention, and FIG. 4 is a diagram for explaining the same embodiment. This is a diagram. 22...Preset counter, 23...Memory device, 32...First control device, 46.Skin...Comparison calculation device, 47...Second control device, 48... ·display. Younger brother I figure 4 figure 2 younger brother figure 3

Claims (1)

[Claims] 1. A latent image forming means for forming a latent image of a document, a copy creating means for creating a plurality of copies from the latent image formed by the latent image forming means, and a number setting means for setting the number of copies;
means for outputting a predetermined number of times the latent image is used, and dividing the set number of copies by the number of times the latent image is formed when the latent image is re-formed every time the latent image is used from this means and the set number of copies are made. a comparison calculation means for setting a number of latent image uses approximately equal to the result of this division; and a comparison calculation means for causing the latent image forming means to re-form a latent image every time the latent image is used for the set number of uses, and causing the copy creation means to re-form a latent image for the set number of copies. and control means for repeatedly operating the copying machine.