JPS58184952A - Electrophotographic copying method - Google Patents

Abstract

PURPOSE:To provide an electrophotographic copying method having no unevenness in an transferred image, not causing failure of separation, and fluctuation of a copy image during repeated uses, by using an Se-As photoreceptor high in optical fatigue, and light emitted from a specified light source, and executing exposure before transfer at a good timing. CONSTITUTION:PTL4 (pretransfer lamp) is selected from electroluminescence, a light emitting diode, and a fluorescent lamp, having >=70% energy of the visible light region in 480-580nm wavelength width. At the start of an electrophotographic copying process, rotation of an Se-As photoreceptor 1 is begun, PTL4 first emits light to expose the photoreceptor 1, when its circumference part comes near a charger 2, it charges the photoreceptor 1, and imagewise exposure takes place. An electrostatic latent image is perfectly formed at this timing on the circumferential region of the photoreceptor exposed to light from PTL4 from the first cycle of the process, and hence, copy image density is normal from the first copy, deterioration of image density from the second copy forth is not observed by the eye, and no residual image occurs.

Description

[Detailed description of the invention] The present invention relates to an electrophotographic copying method.

Se-As formed into a drum or belt shape
By rotating the photoreceptor of the system (hereinafter referred to as the Se-As photoreceptor), an electrostatic latent image is formed on the photoreceptor while its surface is moved cyclically in the direction of the radial direction. An electrophotographic copying process in which a latent image is developed and the resulting visible image is transferred onto a recording medium such as paper is well known.

Se-As photoreceptors are excellent in terms of mechanical strength and sensitivity to broad wavelength chain acid light, but on the other hand, they have the problem of significant optical fatigue phenomenon. There is. The optical fatigue phenomenon referred to here is
Light on 5s-As photoreceptor? By irradiating it, the electrostatic capacity of 1 m of photoconductivity increases and the electrical resistance decreases? 5°.

Because of this optical fatigue phenomenon, the above-mentioned Q]electron photocopying process was continuously performed for 7J using a Se-As photoreceptor.
! Then, there is a problem in that the image sharpness of the obtained copy decreases noticeably as the number of repetitions increases.

As a way to deal with such problems,
It is mainly caused by light in the long wavelength range. 650 nm from the light that exposes one image on the Y surface of the photoreceptor, using a white shield.
The h-method, which cuts out two light components with the above wavelengths, has been tried, and the above problem has been solved to some extent in practice.

By the way, in recent years, visible images formed on photoreceptors in electrophotographic processes using visible image transfer methods have been increasing. It is also desired to improve the transfer efficiency of a visible image when transferring it onto a recording medium. I tried to irradiate it with light through the lens.

The toner that constitutes the 6J holiday is in the photoreceptor. Since it is attached to the surface of the photoconductor by electrical interaction with the toner, the above-mentioned crystal radiation attenuates the above-mentioned charge (traditional charge?) and causes θ to the toner source. ) 1;] Kaoriki Kaoru Komame, -aJOt, 1 copy of the image 9JJ rate Kaoru Koushi Saseru. Such light irradiation is called photoreceptor σ) pre-transfer pancreatic light.

This pre-transfer exposure is extremely effective (σ) and improves the transfer efficiency of the b1 visual image, which has been a serious problem in the past. It was not surprising that the separation performance of the recording medium from the photoreceptor after transfer was also significantly improved.

That is, the above-mentioned pre-transfer exposure can improve the performance of a visible image transfer type electrophotographic copying apparatus, and therefore,
Application to the above-mentioned electrophotographic process using a Se--As photoreceptor is envisaged.

By the way, when pre-transfer exposure is performed at °C, there is a visible image due to toner on the photoreceptor.

The filter effect on visible images is about 20%.

'ij] The part of the photoreceptor 121 at the bottom of the image does not receive strong light, but the part of the photoreceptor that does not have a visible image is about 5 times more sensitive than the part of the photoreceptor below the image. It is difficult to imagine whether this pre-transfer exposure may cause damage to the light on the 5e-As photoreceptor.

In fact, if you carelessly perform two pre-transfer exposures, optical fatigue will occur.

Se-As produced by such pre-transfer exposure
Although the optical fatigue of the photoreceptor is σ, it will be explained in accordance with 4.

For experiments, the inventors created Shigeko 6 as shown in Figure 3.1.
．． Prototype of true first photographic device was made. In the diagram, code 1? to show,
The Se-All photoreceptor is drum-shaped and has a photoconductive layer IJk made of As2Se5, and is rotatable in the direction of the arrow. A charger 2,
Developing device 3. σn light source 4 for pre-transfer light, supervision charger 51, vapor charger 6, cleaner 7, quench/
Granob 8 was deployed as shown. Path light part i: I, charger 2 and current 1 to irradiate the photoconductor 1 with the original light beam
It is set closer to the charger 2 between the pupil 3 and 03, and a position meter 10 is installed between the exposure unit and the developing unit 3, and 1! + After image exposure C! -Light body surface potential? 1 image part corresponding part and ○・benface j1 head 0 vs. 6 parts 1 stand, so I decided to make it 5 to 5.

Boundary 1 and holder 3 are magnetic brush Bandai's, and cleaner 7 is a blade type cleaner.

In addition, light source 4 for exposure before transfer? , hereinafter abbreviated as PTL 4.

The electrophotographic process is performed while rotating the photoreceptor 12 clockwise. Therefore, the basic process is charging by the charger 2.

Image exposure with original light image, dust and image of electrostatic latent image obtained, pre-transfer exposure with PTL 4, transfer/separation charger 5.6. Transfer of the visible image onto the recording medium S, cleaning of the photoreceptor 1 after the transfer by the cleaner 7, and neutralization by the quench/granob 8 are performed in this order.

Of course, the visible image σ) on the recording medium S is produced by an electrolayer device (not shown).

It is fixed on the recording medium S soil.

Furthermore, as the recording medium S, Shintsu paper was used. Further, from the light component of the original image, a light with a wavelength of 650 nm or more was cut, and a quench/granobe 8 was used that was not comparable to the long wavelength luminous component.

When starting a new copying process, i.e. when the main switch of the device is turned on, before starting the electrophotographic copying process.

In preparation for this, the photoreceptor 1 is rotated, and the cleaner 7 cleans it and the quenching knob 8 removes static electricity.
Then, after the previous cleaning, the previous Jf, and the electricity, the photoreceptor 1 is made to stand still, and the condition is now ready for printing, that is, the electrophotographic copying process? Start 5
The state is now set to .

Now, as a PTL 4, is it a tungsten lamp? use,
Rotation of photoconductor 1, charging of photoconductor 1f by charger 2, image exposure of photoconductor 1 by light image of original document Timing of pre-transfer exposure by PTL 4? When the electrophotographic copying process was repeated 10 times in succession with the settings as shown in Figure 2, the surface potential of the photoreceptor measured by the electrometer 10 was as follows: In the area corresponding to the image area, the change was as shown in curve 3-1 in Figure 3, and in the non-image area, the change was as shown in curve 3-2 in the same figure. Subject::\1 1iii1 The image density of the second and subsequent copies of the 1 image visibly decreases, and even in the first copy, it is exposed to light by PTL 4 before being charged by charger 2. The image density of the area corresponding to the body part was much lower than the image density of the area other than the wrinkles.

In addition, so-called afterimages were observed in the images after the second one.

This 5-sum phenomenon is caused by optical fatigue of the photoreceptor 1 due to PTL 4. That is, the long wavelength component of the light from the tungsten lamp used as the PTL 4 penetrates the photoconductive layer of the photoreceptor 1 and generates carriers deep inside the pigeon. Among the generated carriers, electrons with low mobility are trapped and act as a space charge distribution within the photoconductive layer.

Due to this influence, the charge level of the photoreceptor after exposure by PTL 4 decreases. That is, P.T.L.
Exposure according to 4 causes the photoconductive layer of photoreceptor l to increase its capacitance and decrease its resistance.

In view of the above-mentioned problems, the present invention effectively prevents the phenomenon of light fatigue in a light body when the fj% of the pre-transfer exposure is 1≧Se-As.

Providing a new electrophotographic process? purpose.

Below, the present invention Yg! :explain.

The features of the present invention are as follows:
8.

In other words, the problem lies in the light source for pre-transfer exposure.

More than 70% of the energy of the electroluminescent lamp is emitted from a fluorescent lamp σ), and its stiffness is generated by a wavelength range of 480 to 580 nm.
The light of m is to be selected.

3.2, just before starting the electrophotographic process,
Photoreceptor? As it is rotated, the pre-transfer exposure θ) light #i is emitted for 1 inch, and the electrostatic latent image is formed in the uniformly exposed curved area of the photoreceptor by the light σ] from this light source. The timing of the formation depends on the timing.

2, 2, 2, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 4, 4, 7, 7, 7, 8, 8, 7,, 7,,, 7,,,, 7,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, I will,,,,,,, I will,.

In the example of the device shown at 3'1 south, PTL4 is set and the helmet light 1- is set in green. Electroluminescence? Use,
At the timing shown in Figure 2, the above and l'J 4i
``The experiment was conducted.
The timing shown in figure 2 of the above standby is also θ).
Part 2, Kaoru Kaoru, is not satisfied.

Now, with the repetition of the electron photographing process, the surface potential of the photoreceptor l changes as shown by curves 3-3 and 3-4 in Figure 3.3. Indicated. Of course, one song 13-3 has a potential at a portion corresponding to an image portion.One song IkI3-4 has a potential at a portion corresponding to a non-image portion.

As is clear from the figure, the phenomenon of optical fatigue has not been effectively eliminated in the photoreceptor 1. After the second process repetition, the e-plane potential changes only slightly, +m
Almost no decrease in image density was observed.

The reason for the stiffness is that the light from PTL 4 contains almost no long wavelength light components, so the Q of the photoconductive layer irradiated by PTL 4 is
) Carrier generation is mostly limited to the surface.

For this reason, the capacitance in the photoconductor 1 is almost increased, and therefore, optical fatigue of the photoreceptor does not occur.

However, N' Figure 2 θ] Timing As can be seen, the photoreceptor 1 is charged by the charger 2.

Since the light emission of PTL 4 and the rotation of the Asahi photoconductor l occur simultaneously, when the rotation of the photoreceptor l starts, the PTL
The peripheral surface of the photoreceptor from the 4σ) position clockwise up to the charger 2 does not receive the path light from the PTL 4.

Therefore, in the first copy, the upper mll red light receiver'
The image and opening degree of the portion corresponding to the area subsequent to the writing area were lower than the image of 6 degrees of the portion corresponding to the peripheral surface area where there is no writing area. The problem is that in the part illuminated by PTL 4,
Even if the light has a short wavelength, there are many photoelectrons, so the number of generated carriers is also large, and it is thought that this is because the medium receiving resistance near the surface of the photoconductive layer is temporarily lowered.

So, next, what is the timing of charging by charger 2 and the timing of image 11% light? On the contrary, I conducted an experiment similar to the one above at the timing shown in Figures 3 and 4. this,
The timing shown in Figures 1 and 4 satisfies the 2σ] Kasou in Hoka: 4/J.

That is, at the beginning of the electronic copying process, the photoreceptor 1 starts rotating at 1.1'; the PTL 4 emits light and illuminates the photoreceptor 1. However, the part of the photoconductor cylinder surface where the light traced like this is the charger 21]
When it gets close, charger 2 charges it, and then I[! iI image exposure is performed 4).

At this timing, from the 11th (gith)'' process, the electrostatic latent image is completely formed on the peripheral surface of the photoreceptor exposed by the PTL 4, and therefore the image on the first copy is Stepwise changes in concentration can be prevented.

As a result of the experiment, the surface potential of the photoreceptor was determined by the process σ] depending on the number of repetitions, the song of 1 year old 5 figure +11i15-1゜5- for the image area corresponding site, non-image area vs. 2
It became something like this.

There was no abnormality in the image density of the copies from the first copy, no decrease in density was observed visually after the second copy, and no residual flaws were observed.

A similar experiment was carried out using one light emitting diode (Toshiba TLUG 565 nm peak, half width 25 nm) as PTL.
Ya, fluorescent lamp (Yoneshiba FL) 5G, 15W, 540n
m peak), but similar good results were obtained as with electroluminescence).

As described above, according to the present invention, Se −
By using an As photoreceptor and performing path light 2 before transfer,
Translation '4 hiraya, nukiyo grosses without separation failure? It is possible to provide a copying method that can be realized and has almost no variation in one copy image even due to changes in the process.

Note: 1. In principle, the present invention does not require long wavelength components. Miyato: Since the purpose is to perform light beaming on the photoreceptor before transfer with a low amount of light, for example, it is possible to use a tungsten lamp as a PTL and cut off unnecessary light components with a filter to perform path light before transfer. However, if you do it like this, in reality,
The cost of filters is quite high. Contrary to this, when the light source exits the light source, there is no public security that uses a filter,
It is possible to realize a light source for pre-transfer light in one song.

[Brief explanation of the drawing]

4'I figure to 3 figures are 1) figure 7' to explain the nature of the problem to be solved by the present invention, 7' figure & J, 2nd σ of Hontanmon] Figure for simple explanation, 3・Figure 5 is a diagram for explaining the effects of the present invention. l...Se-As photoreceptor, 2...charger,
3... Glare 1 head mounted, 4... Light source for Fukuko before transfer, S...
・Record 3

Claims (1)

[Claims] Se-As formed in a drum shape or belt shape
Rotate the photoreceptor of the system and change the surface to the circumferential direction 1bj
The photoreceptor is uniformly charged while being moved cyclically to the photoreceptor, and then imagewise exposed with light that cuts out light of 650 nm or more to form an electrostatic latent image. , a visible image could not be obtained on the photoreceptor? 17 tit
In an electrophotographic copying method for transferring onto a recording medium. The light source for pre-transfer light includes electroluminescence, a light emitting diode, and a fluorescent wrap, which contain light with a wavelength width of 480 to 580 nm at least 70% of the energy in the visible light range. 1' When starting the copying process, the photoreceptor is rotated, and the light source for pressure is emitted before the transfer, and the peripheral surface area of the photoreceptor is uniformly exposed to σ] light from this light source. An electrophotographic copying method characterized by forming an electrostatic latent image within the image.