JPS60151684A - Electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To hold the insulation of a photosensitive surface and form a sharp copy image by forming a protection layer for dampproofing or prevention against dew condensation on the surface of a photosensitive body unless a next copy is taken within a specific time after the copying process of an electrophotographic copying machine. CONSTITUTION:A normal electrostatic latent image is formed and developed by a corona electrifier 2, exposing device 20, developing device 3, and transferring device 4 provided at the circumference of the rotating cylindrical photosensitive body 1, and the image is transferred 4 to copy paper (not shown in figure) from a cassette 12; the photosensitive paper is separated 6 by being destaticized by a corona destaticizer 5, the toner image is fixed 14, and the copy paper is discharged 15a and 15b. The photosensitive body 1 further turns to be destaticized by a destaticizer 7, cleaned 8, and destaticized by a destaticizer 9 and then returns to its initial state, thereby entering the next copying process. If copying operation is not performed within the specific time, the protection layer for dampproofing or dew condensation prevention is formed on the photosensitive surface of the photosensitive body 1 by the corona charger and developing device 3. Consequently, the insulation of the photosensitive surface is held excellently and the characteristics of the photosensitive surface are improved to form a sharp image.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electronic copying apparatus capable of preventing moisture or dew condensation on a photoreceptor.

[Technical background of the invention]

Conventionally, the photosensitive surface of a photoreceptor, which is made by depositing amorphous selenium or the like on a metal plate, is first uniformly charged by positive corona discharge in a dark place to become photosensitive. Next, imagewise exposure is performed with light or radiation to attenuate the charge in the exposed areas to create an electrostatic latent image. Toner having a charge opposite to that of the latent image is electrostatically attracted to this electrostatic latent image.

A sheet of paper is placed on top of this toner image, and the back surface of the sheet of paper is electrostatically transferred by positive corona discharge again, and then the copied toner image is heated and fixed on the sheet of paper. On the other hand, toner remaining on the surface of the photoreceptor is removed by a cleaning brush or the like.

According to this apparatus, the photosensitive surface is exposed to air for a long period of time until the surface of the photosensitive member is cleaned after the copying process is completed. Moreover, the transfer paper comes into contact with the photoreceptor during the copying process.

A very small amount of paper dust adheres to the photosensitive surface. This paper dust is removed during the cleaning process, but if the photoreceptor is used for a long time, it may not be completely removed even after cleaning, and the paper dust may adhere to the photosensitive surface.

When paper dust adheres to the photoreceptor in this way, ozone and nitrogen oxides in the air tend to adhere to the surface of the photoreceptor. Therefore, if the photoreceptor is left in a high humidity atmosphere, the surface of the photoreceptor tends to absorb moisture or condense due to the effects of paper dust, ozone, nitrogen oxides, etc., and the insulation of the photoreceptor surface is impaired. If you make a copy in this condition, the copied image may be blurred or
If it bleeds or gets worse, you may not be able to draw the picture at all.

Currently, in order to solve this problem, measures are being taken such as installing a heater in the device to lower the humidity, and mixing an abrasive or the like into the toner to clean the surface of the photoreceptor.

However, if a heater is provided in the device, the power consumption will increase accordingly, and the configuration will become complicated, which is disadvantageous in terms of miniaturization. However, if an abrasive is mixed into the toner, the surface of the photoreceptor will be abrasive, which will shorten the life of the photoreceptor.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an electronic copying apparatus that prevents moisture absorption and dew condensation on the surface of a photoreceptor and obtains clear copied images.

[Summary of the invention]

In this invention, an image is exposed on the photosensitive surface of a uniformly charged photoreceptor to form an electrostatic latent image, and toner is electrostatically attracted to this electrostatic latent image to develop a copy toner image on transfer paper. In an electronic copying apparatus that obtains a copy image by transferring, a protective layer for preventing moisture and condensation is formed on the photosensitive surface using a protective layer forming means after the copying process is completed.

The protective layer forming means, which forms a moisture-proof and anti-condensation protective layer on the photosensitive surface of the photoconductor, is not yet activated by the anti-static circuit when the output of the detection circuit that detects the frequency of use of the photoconductor exceeds a set value. The feature is that the system can be switched to automatic or manual operation.

[Embodiments of the invention]

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

In FIG. 1, reference numeral 1 denotes a selenium-based photoreceptor formed into a cylindrical shape in order to automate the process, and a corona charger 2. Developing device 3. Transfer charger 4. AC corona static eliminator5. Peeling nail 5. AC corona static eliminator7. Cleaning device8. A static elimination lamp 9 is provided. Also, a pair of feed rollers 10a and 10b that convey the transfer paper to the upstream side of the transfer charger 4.

A gate 11 and a pick-up roller 13 that pulls out the transfer paper into a cassette are disposed, and a fixing device 14 is provided downstream of the charger 4 to heat and fix the toner image transferred onto the transfer paper, and a fixing device 14 that heats and fixes the toner image transferred onto the transfer paper. A pair of non-paper rows 2 that carry out
15a and 15b are arranged. It has the function of re-driving when it fails. Also.

The cleaning blade 8a of the cleaning device 8 has the function of cleaning the photosensitive surface of the photoreceptor 1 by contacting it only during the copying process, and is held away from the photosensitive surface after the copying process is completed. The corona charger 2 and the developing device 3 constitute a protective layer forming means for forming a moisture-proofing or dew-preventing protective layer on the photosensitive surface after the copying process is completed.

On the other hand, a document table glass 17 constituting a document placement surface is movably provided on the upper surface of the one-machine box 16, and a platen cover 18 is provided on the document table glass 17 so as to be openable and closable. An optical system such as an exposure lamp 19, 71 and an optical lens array 20 is disposed below the document table glass 17.

Next, the operation of this device will be explained using the time chart shown in FIG. At the rise of the pulse signal of the copy operation button, the main motor is turned on and the photoreceptor 1 begins to rotate.
AC corona static eliminator7. Static elimination lamp9. feed roller 10
a-, 10b are turned on. Also.

At the same time, the cleaning solenoid is turned on and the blade of the cleaning device 8 is pressed against the photosensitive surface of the photosensitive member 1. At this time, the toner on the photoconductor 1 is cleaned by the blade.

The charge on the photoreceptor 1 is removed by the charge removal lamp 9.

When the above-mentioned pre-cleaning process A is completed, the document table clutch nod is turned on and the document table glass 17 starts to move. Subsequently, the pickup roller 13 is driven to pull out the transfer paper from the cassette 12.

Immediately after this, the first developing motor and the exposure rung 19 are turned on, and the image of the document is formed on the photosensitive surface of the photosensitive member 1 through the fiber lens array 20. next.

The corona charger 2 is turned on, and the photosensitive surface of the photoreceptor 1 is positively charged and photosensitive in a dark place. As a result, an electrostatic latent image of the document is formed in the image area of the photoreceptor 10. The developing device 3 electrostatically attracts negatively charged toner to this electrostatic latent image and develops it. The transfer paper conveyed by the feed rollers 10a and 10b is superimposed on the thus obtained copy toner image. At this time, when the pulse signal of the gate 11 falls, the transfer charger 4. The static eliminator 5 turns on,
Pickup low 213 is turned off. Then, a transfer charger 4 is used to positively corona-charge the transfer paper from the back side for electrostatic transfer, and an AC corona charge remover 5 removes the charge from the transfer paper to weaken the electrostatic adhesion of the transfer paper. This transfer paper has 6 peeling claws
After being peeled off from the photoreceptor 1 by , it is sent to a fixing unit 13 . Here, the toner image is heated and fixed onto the transfer paper. At this time, the cod light lamp 9 is turned off, and then the transfer aV% meter 4. The AC corona remover 1E device 5 is turned off.

On the other hand, after the transfer paper is peeled off, the photoreceptor 1 is neutralized by an AC corona static eliminator 7 to make it easier to remove the toner adsorbed to the photoreceptor 1. This toner is removed by cleaning N:8. In this manner, charges are removed from the cleaned photosensitive surface of the photosensitive member 1 by the charge removal lamp 9. Then the main motor.

Cleaning solenoid, document platen claratin renoid,
Developing motor, corona charger2. AC corona static eliminator7. Static elimination lamp9. Feed rollers 10a and 10b are turned off.

After the above-described copying process B is completed, when the copying standby period C has elapsed for a certain period of time, for example, 3 minutes, the main motor and the developing motor are turned on, and then the corona charger 2 is turned on.

At this time, the blade of the cleaning device 8 is cut away from the surface of the photoreceptor 1 and held at a predetermined position. In this state, the photosensitive surface of the photosensitive member 1 is uniformly charged with a corona charger 2, and the developing device electrostatically attracts toner to the photosensitive surface, thereby developing the entire photosensitive surface. After the process of forming the protective layer is completed, this toner adheres to the photosensitive surface by van der Waalska and is used as a protective layer for preventing moisture or condensation on the photosensitive member 1.

Therefore, according to the configuration described above, after the copying process B is completed, the protective layer forming line sD can be completed when the copying process is not executed for a certain period of time (3 minutes in the example), so that the final copying is not completed. A protective layer can be formed on the photosensitive surface at this point. Moreover.

By executing the copying process B during the copying standby period C, the copying process B can be executed continuously without executing the protective layer forming process, without reducing the copying execution speed. live in

Next, another embodiment of the invention will be described. A counter for counting the number of copies is provided as a detection circuit for detecting the frequency of use of the photoreceptor 1 in the apparatus of the above embodiment, and when this counter reaches a set value, a dew condensation prevention device is installed on the photosensitive surface of the photoreceptor l. A control circuit is provided to automatically switch the protection 1 [1 forming means for forming the protective layer for use] to automatic operation.

In this way, by adding a counter and a control circuit to the apparatus of the above embodiment, when paper dust adheres to the photosensitive surface and it becomes susceptible to the effects of ozone and nitrogen oxides, the same protective layer forming means as above can be used. can be executed automatically.

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without changing the gist.

For example, in the above embodiment, the backup hE7 forming process is executed when the copying process is not executed even after a certain period of time has passed after the copying process is completed, but the present invention is not limited to this. So &(.

The protective layer forming step can be performed in succession to the copying step.

Although in the other embodiments described above, the protective layer forming means was switched to automatic operation using the control circuit, the present invention is not limited to this, and the protective layer forming means can also be switched to manual operation.

Furthermore, the control circuit of the other embodiments described above may be provided with an indicator that notifies that the output of the detection circuit has reached a set value.

〔Effect of the invention〕

According to this invention, by covering the photosensitive surface of the photoreceptor with a protective layer after the copying process is completed, the photosensitive surface is freed from paper dust.

Since the photosensitive surface can be protected from the effects of ozone, nitrogen oxides, etc., moisture absorption or dew condensation on the photosensitive surface can be prevented. In this way, by making the photosensitive surface moisture-proof or preventing condensation with the protective layer, W! & Good insulation of the optical surface and charging characteristics of the photoreceptor 1.

It is possible to improve image characteristics and always obtain clear copied images.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a timing chart for explaining the operation of the embodiment. 1-. Photoreceptor 2... Corona charger 3... Developing device 4... Transfer charger 5... AC corona static eliminator 6... Peeling claw 7... AC corona static eliminator 8. ... Cleaning device 9 ... Static elimination lamp 10
a, 10b...Feed roller 11...Gate
12...Cassette 13...Pickup roller 1
4...Fuser 15a, 15b...Non-paper roller 1
6...Machine box 17...Original table glass 18...Platen cover 19...Exposure lamp 20...Fiber lens array A...Breakley double/g process B...Copying process C...・Copying waiting period D...Protective layer formation process Applicant Olympus Optical Industry Co., Ltd.

Claims (1)

[Scope of Claims] (1) Copy toner produced by exposing an image to a photoconductor whose photoconductor surface is uniformly charged to form an electrostatic latent image, and developing the toner by electrostatically adsorbing the toner to this electrostatic latent image. In an electronic copying apparatus that obtains a copy by transferring an image to a transfer paper, a protective layer forming means for forming a moisture-proofing or dew-preventing protective layer on the photosensitive surface is executed after the copying process is completed. range 1
Electronic copying device as described in Section 1. (3) J: The electronic copying apparatus according to claim 1, wherein the protective layer forming means is executed continuously during the copying process. (4) The electronic copying apparatus according to any one of claims 1 to 3, wherein the protective layer forming means uniformly develops the entire photosensitive surface of the photoreceptor with toner. (5) An electrostatic latent image is formed by exposing an image to a photoreceptor whose photosensitive surface is uniformly charged, and the toner is electrostatically attracted to this electrostatic latent image to develop a copy toner image onto transfer paper. An electronic copying apparatus for obtaining a copy image by transfer, comprising: a protective layer forming means for forming a moisture-proof or anti-condensation protective layer on the photosensitive surface of the photoconductor; a detection circuit for detecting the frequency of use of the photoconductor; An electronic copying apparatus comprising: a control circuit that switches the protective layer forming means to automatic operation or manual operation if the output of the detection circuit exceeds a set value. (6) The electronic copying apparatus according to claim 5, wherein the detection circuit counts the number of copies. (Force) The electronic copying apparatus according to claim 5, wherein the control circuit includes an indicator for notifying that the output of the detection circuit has reached a set value.