JP2002108032A - Electrophotographing method and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographing method and an electrophotographic device capable of providing a copied image of high image quality by reducing latent ghost memories on an a-Si photoreceptor, and also, suppressing potential irregularities. SOLUTION: In the electrophotographing method and the electrophotographic device for forming the image through at least processes of discharging, electrifying, exposing a latent image, developing and transferring, at least the photoreceptive layer of the photoreceptor as a recording element is constituted of amorphous material, and such the light is used for the image-exposure for forming a latent image that the value of an optical memory to a unit contrast potential becomes the smallest as for the peak wavelength of the light in emission spectrum, and also, the light having a half value width of <=50 nm at the peak in the emission spectrum is used for destaticizing-exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic method and an electrophotographic apparatus using a corona discharge type charger.
More specifically, an amorphous silicon-based photoreceptor (hereinafter, referred to as
Abbreviated as a-Si photoconductor. The present invention relates to an electrophotographic method and an electrophotographic apparatus using the method, and more particularly, to a latent image in an a-Si photosensitive member.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic method and an electrophotographic apparatus capable of providing a high-quality copy image by reducing a memory and a potential unevenness.

[0002]

2. Description of the Related Art In electrophotography, a photoconductive material for forming a photosensitive layer in a photoreceptor has high sensitivity, a high SN ratio [photocurrent (Ip) / dark current (Id)], and a spectrum of an electromagnetic wave to be irradiated. It is required to have characteristics such as having an absorption spectrum suitable for the characteristics, quick light response and a desired dark resistance value, and being harmless to the human body during use. In particular, in the case of a photoconductor for an image forming apparatus incorporated in an image forming apparatus used in an office as an office machine, the above-described non-pollution during use is important. Hydrogenated amorphous silicon (hereinafter referred to as “a-Si:
H "), for example, Japanese Patent Publication No. 60-3505.
No. 9 describes an application as a photosensitive member for an image forming apparatus.

In general, a photosensitive member for an image forming apparatus using a-Si: H is prepared by heating a conductive support to 50 ° C. to 400 ° C. and depositing the conductive support on the support by a vacuum deposition method, a sputtering method, or the like.
A photoconductive layer made of a-Si is formed by a film forming method such as an ion plating method, a thermal CVD method, a photo CVD method, and a plasma CVD method. Among them, the plasma CVD method, that is,
A method in which a source gas is decomposed by direct current, high frequency, or microwave glow discharge to form an a-Si deposited film on a support has been put to practical use as a suitable method.

In Japanese Patent Application Laid-Open No. 56-83746, a conductive support and an a-Si (hereinafter referred to as "a-Si: X") photoconductive layer containing a halogen atom as a constituent element are disclosed. Photoconductors for image forming apparatuses have been proposed. In this publication, one halogen atom is added to a-Si.
By containing from 40 to 40 atomic%, heat resistance is high,
Good electrical as photoconductive layer of photoreceptor for image forming device,
It is said that optical characteristics can be obtained.

Japanese Patent Application Laid-Open No. Sho 57-115556 discloses that a photoconductive member having a photoconductive layer composed of an a-Si deposited film has an electrical property such as a dark resistance value, photosensitivity, and photoresponsiveness. In order to improve the use environment characteristics such as optical and photoconductive properties and moisture resistance, as well as the stability over time, silicon atoms and carbon are deposited on a photoconductive layer composed of an amorphous material based on silicon atoms. A technique of providing a surface layer made of a non-photoconductive amorphous material containing atoms is described.

Further, Japanese Patent Application Laid-Open No. 60-67951 describes a technique relating to a photoconductor in which a light-transmitting insulating overcoat layer containing amorphous silicon, carbon, oxygen and fluorine is laminated. 62-168161
Japanese Patent Application Laid-Open Publication No. H11-163,887 describes a technique using an amorphous material containing silicon atoms, carbon atoms, and 41 to 70 atomic% of hydrogen atoms as constituent elements as a surface layer.

Further, Japanese Patent Application Laid-Open No. 57-158650 discloses that an infrared absorption spectrum containing 10 to 40 atomic% of hydrogen has an absorption coefficient ratio of absorption peaks at 2100 cm -1 and 2000 cm -1 of 0.2 to 2,000 cm -1. It is described that a photosensitive member for an image forming apparatus having high sensitivity and high resistance can be obtained by using a-Si: H of 1.7 for the photoconductive layer.

On the other hand, Japanese Patent Application Laid-Open No. 60-95551 discloses that in order to improve the image quality of an a-Si photoreceptor, the temperature near the surface of the photoreceptor is maintained at 30 to 40.degree.
By performing image forming processes such as development and transfer,
There is disclosed a technique for preventing a reduction in surface resistance due to the adsorption of moisture on the surface of a photoreceptor and the resulting image deletion.

[0009] These techniques have improved the electrical, optical, photoconductive and operating environment characteristics of the photoreceptor for an image forming apparatus, and accordingly the image quality.

[0010]

As the electrophotographic apparatus is used for other purposes and the space of an office or the like is reduced, a space-saving, multifunctional, and high-speed copying apparatus is required. Therefore, speeding up from the design aspect,
It must be downsized and multifunctional.

However, with the increase in speed, miniaturization, and multifunctionality of the electrophotographic apparatus, the miniaturization of the charging device,
As the process speed increases, the passage time of the photoconductor in the charger becomes short, and it becomes difficult to obtain high charge on the photoconductor surface. From the viewpoint of energy saving, it is necessary to reduce the power consumption of the entire electrophotographic apparatus by cutting the drum heater and reducing the current value of the charger.

In particular, when the speed is increased or the diameter of the photosensitive member is reduced, a large problem occurs with respect to charging. In the case of high speed, even when the width of the charging device is the same, the time required for the photoconductor to pass through the charging device is shortened, and the charging ability is reduced. Also,
When the diameter is reduced, charging cannot be sufficiently obtained because the width of the charger is limited.

As a common problem in increasing the speed and reducing the diameter of the photoreceptor, the time from the exposure to the charger may be shortened. When amorphous silicon is used, a problem of optical memory due to exposure occurs. This optical memory decreases with time after exposure, and the shorter this time is, the more likely it is to appear as a ghost in an image. To erase the optical memory called ghost, it is possible to give excessive exposure to static elimination,
Increasing the amount of light for the charge-removal exposure resulted in the phenomenon that the chargeability decreased.

Japanese Patent Application Laid-Open No. 60-16187 discloses a technique for preventing ghost by using a laser of near-infrared exposure and using a light having a wavelength of 600 to 800 nm for static elimination light. Japanese Patent Application Laid-Open No. 58-102970 discloses that laser exposure uses a wavelength of 600 to 700 nm to prevent deterioration,
A technique for improving the mechanochemical durability is disclosed.

However, a method for comprehensively improving the charging ability, ghost, potential unevenness, etc., is not disclosed, and these problems are encountered when applied to a high-speed digital machine or a digital machine using a small a-Si. Had to be resolved.

Therefore, when designing an image forming apparatus or an electrophotographic image forming method, the electrophotographic physical properties, mechanical durability and the like of the photoreceptor for the image forming apparatus are set so as to solve the above-mentioned problems. There is a need to improve from a comprehensive point of view, and to further improve a charging device and an image forming apparatus that have good charging efficiency and uniform charging.

That is, an object of the present invention is to provide an electrophotographic method and an electrophotographic apparatus capable of reducing a ghost memory latent in an a-Si photosensitive member, reducing potential unevenness, and providing a high-quality copy image. It is in.

[0018]

An object of the present invention is to provide at least an electrophotographic method (or electrophotographic apparatus) for forming an image by static elimination, charging, latent image exposure, development and transfer.
The photosensitive element as a recording element, at least the light receiving layer is made of amorphous, and, for image exposure for forming a latent image, using light in which the peak wavelength in the emission spectrum has the minimum value of the optical memory with respect to the unit contrast potential, In addition, the half width of the peak in the emission spectrum is 50 nm for the charge removal exposure.
This is achieved by an electrophotographic method (or an electrophotographic apparatus) using the following light.

It is a further object of the present invention to at least eliminate static electricity,
In an electrophotographic method (or an electrophotographic apparatus) in which an image is formed by charging, latent image exposure, development and transfer, at least a photoreceptor serving as a recording element has an amorphous light-receiving layer,
An electrophotographic method (or electrophotographic apparatus), wherein light having a peak wavelength in an emission spectrum, a value of an optical memory with respect to a unit contrast potential, and a peak half-value width of 50 nm or less is used for image exposure for forming a latent image.
Is achieved by

It is a further object of the present invention to at least remove static electricity,
In an electrophotographic method (or an electrophotographic apparatus) in which an image is formed by charging, latent image exposure, development and transfer, at least a photoreceptor serving as a recording element has an amorphous light-receiving layer,
In the latent image forming image exposure, light having a peak wavelength in the emission spectrum at which the value of the optical memory with respect to the unit contrast potential is minimized, and light having a peak half-value width of 50 nm or less is used. This is achieved by an electrophotographic method (or electrophotographic apparatus) using light having a half width of 50 nm or less.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a result of repeated studies by the present inventors in order to solve the above-mentioned problems, the present inventors have found that by using light having a wavelength and a half-value width determined in the present invention for image exposure and static elimination light. Ghost and potential unevenness can be improved even under severe conditions of charging ability such as high speed, small photoconductor diameter,
The present inventors have found that it is not necessary to irradiate an excessive charge for removing static electricity, and that a sufficient charged potential can be obtained, thereby completing the present invention.

In the present invention, the image exposure is performed so that the optical memory at the unit contrast potential is minimized under the condition that the difference (contrast potential) between the dark portion potential and the bright portion potential is kept constant. As a result, the charging ability and the ghost memory can be improved. Further, by setting the half width of the emission peak in the spectrum of the static elimination light to 50 nm or less, the potential unevenness could be improved.

Hereinafter, the present invention will be described in more detail.

FIG. 2 shows the sensitivity at each wavelength of the a-Si photosensitive member. The sensitivity was shown by the value of the surface potential which was reduced at a constant light amount. It is considered that the a-Si photoreceptor has a sensitivity peak near 700 nm, and at a wavelength of 700 nm or more, sufficient energy of more than a band gap cannot be imparted, so that the sensitivity sharply decreases.

However, simply using a wavelength having a high sensitivity as an image exposure light source was insufficient for using an a-Si photosensitive member. This is because a-Si generates an optical memory by exposure, so that the effect of improving the ghost cannot be sufficiently obtained only by using the wavelength having the highest sensitivity as the wavelength of the image exposure.

The inventors of the present invention have studied and, as a result, have succeeded in quantifying, for each wavelength, how much light irradiated before charging is involved in an optical memory. FIG. 3a) shows the decrease in the generated charging potential under a constant light amount. Hereinafter, this decreased value of the potential is referred to as an optical memory. Also,
FIG. 3B) shows the results of measuring the optical memory while changing the time from light irradiation to charging. The longer the time from exposure to charging was, the smaller the optical memory was, but the peak wavelength of the optical memory remained almost unchanged. From these results, it was found that the wavelength at which the charging ability was reduced was light near 730 nm. The unit of time in FIG. 3B is seconds.

FIG. 1 is obtained from the above two experiments. FIG.
Was obtained by dividing the value of the optical memory for each wavelength in the curve 2 in FIG. 3A by the corresponding sensitivity for each wavelength in the curve 2 in FIG. FIG. 1 shows the result of calculating the optical memory at the unit contrast potential of the photoconductor used in Experimental Example 1 for each wavelength.

From the above results, it can be seen that in order to reduce the memory such as ghost while maintaining the sensitivity, it is necessary to reduce the ratio of the optical memory to the sensitivity of the photosensitive member. That is, it has been found that the ghost potential can be reduced by using image exposure that minimizes the optical memory generated at the unit contrast potential.

The image exposure wavelength ranges from 500 nm to 68
It has been found that the use of 0 nm exposure improves the rank of the ghost memory on the image. More preferably, the range from 600 nm to 660 nm was effective. The use of the image exposure light source having the minimum value of the pre-charge exposure memory with respect to the sensitivity as described above allows the a-Si photosensitive member to have a high a-Si photoreceptor even under severe charging ability conditions, such as a high-speed and small-diameter photosensitive member. It is effective for charging ability.

This is considered for the following reasons. When the wavelength of the image exposure is larger than 660 nm, the optical memory becomes large. Conversely, at a wavelength smaller than 600 nm,
When a light source such as an LED or a semiconductor laser is used, it is considered that the residual potential is increased, the apparent sensitivity is reduced, and an excessive amount of light is irradiated, so that the optical memory is increased.

When a semiconductor laser is used, the dot diameter can be reduced at the optical design level by using these wavelengths. Thereby, a high-quality image can be obtained.

The optimum charge-removal exposure in the case of using the above-mentioned image exposure in the present invention will be described below. When the wavelength of the neutralization light is larger than 680 nm, the potential unevenness tends to increase rapidly. This is presumably because, when the film quality is uneven, the optical memory is likely to be uneven due to the static elimination light. Also, as the wavelength becomes shorter on the shorter wavelength side,
The reason why the unevenness is increased is that unevenness of the residual potential is generated.
It has been found that it is preferable to use a neutralization exposure of not more than 630 nm, more preferably not less than 630 nm and not more than 680 nm.

Furthermore, as a result of diligent studies on the correlation between the charge elimination light and the half-width of the peak of image exposure and the potential unevenness, the potential unevenness depends on the half-width of the peak, and the half-width of the peak is reduced. Improves unevenness in potential, and
In the following, it was found that even when an LED having a peak wavelength of 700 nm was used, the level was improved to a considerably good level. This is considered to be because the light absorption region in the depth direction of the photoreceptor becomes uniform by reducing the peak half-value width, and apparently the causes of unevenness such as optical memory unevenness and residual potential unevenness become uniform. . The peak half-value width here is the width of the wavelength at which the light intensity is １ ／ of the maximum value in the spectral distribution of the light source as shown in FIG.

The result that the potential unevenness improving effect by reducing the peak half width depends on the moving speed of the surface of the photoreceptor was obtained.

That is, the moving speed is 200 to 60.
At 0 mm / sec, a particularly large effect was recognized. This is considered for the following reason. Taking the case of static elimination light as an example, the moving speed is 200 mm /
If it is smaller than sec, the time from the charge erasing process to the charging process becomes longer, unevenness caused by the charge erasing process such as an optical memory is alleviated, and the potential unevenness is improved irrespective of the peak half width of the charge erasing light. Can be Further, when the moving speed is higher than 600 mm / sec, the time required to pass through the charging device process is shortened. Therefore, it is considered that the unevenness caused by the charging process becomes more dominant than the unevenness caused by the static elimination light. .

Further, as a result of evaluating the ghost potential with respect to the charging ability, it was found that satisfying the above range was effective in improving the ghost memory.

As described above, in order to satisfy all three points of charging ability, ghost, and charging potential unevenness, it is necessary to perform image exposure,
It has been found necessary to use static elimination exposure within the scope of the present invention.

Hereinafter, the photoconductive member of the present invention will be described in detail with reference to the drawings. FIG. 4 is a schematic configuration diagram for explaining a layer configuration of a photoconductor for an image forming apparatus. In the photoconductor 500 for an image forming apparatus shown in FIG. 4A, a photosensitive layer 502 is provided on a support 501 for the photoconductor. The photosensitive layer 502 is composed of a photoconductive layer 503 made of a-Si containing hydrogen atoms and / or halogen atoms (hereinafter abbreviated as a-Si: H, X) and having photoconductivity. FIG. 4B is a schematic configuration diagram for explaining another layer configuration of the photoconductor for an image forming apparatus. FIG.
In the photoreceptor 500 for an image forming apparatus shown in (b), a photosensitive layer 502 is provided on a support 501 for a photoreceptor. The photosensitive layer 502 includes a photoconductive layer 503 made of a-Si: H, X and having photoconductivity, and an amorphous silicon-based surface layer 504. FIG. 4 (c)
FIG. 4 is a schematic configuration diagram for explaining another layer configuration of the photoconductor for an image forming apparatus. In the photoconductor 500 for an image forming apparatus shown in FIG. 4C, a photosensitive layer 502 is provided on a support 501 for the photoconductor. The photosensitive layer 502 is made of a-Si: H, X and has photoconductivity.
03, an amorphous silicon-based surface layer 504, and an amorphous silicon-based charge injection blocking layer 505.

FIG. 4D is a schematic configuration diagram for explaining still another layer configuration of the photosensitive member for an image forming apparatus.
The photosensitive member 500 for an image forming apparatus shown in FIG. 4D has a photosensitive layer 502 provided on a support 501 for the photosensitive member. The photosensitive layer 502 includes a charge generation layer 507 and a charge transport layer 508 made of a-Si; H, X constituting the photoconductive layer 503 and an amorphous silicon-based surface layer 5.
04.

Hereinafter, the effects of the present invention will be specifically described with reference to experimental examples. The present invention is not limited to these experimental examples.

(Experimental Example 1) Using an apparatus for manufacturing a photoreceptor for an image forming apparatus by a plasma CVD (RF-PCVD) method using a radio frequency, on a mirror-finished aluminum cylinder having a diameter of 108 mm as shown in Table 1. Under the conditions shown, a photoreceptor comprising a charge injection blocking layer, a photoconductive layer and a surface layer was prepared.

[0042]

[Table 1]

The result of calculating the optical memory at the unit contrast potential of the photoreceptor for each wavelength is as shown in FIG. 1 as described above.

The photosensitive member thus prepared is set in an electrophotographic apparatus shown in FIG. 18 and evaluated. As shown in this figure, a cylindrical electrophotographic photosensitive member 60 rotating in the R1 direction
1, a main charging device 602, a developing device 603,
A separation charger 604, a cleaning device 605, a main static elimination light source 606, and an exposure device 607 are provided.

In the present invention, the prepared photoreceptor was set in an image forming apparatus (NP6060 manufactured by Canon Inc. modified for digital test) to evaluate the charging ability and the rank of the ghost memory. The pre-exposure uses a 680 nm LED, the image exposure uses a 700 nm LED, and the photoreceptor uses 300 mm / sec.
It rotated at the speed of c. Charging ability is 10 times the current of the primary charger.
The value at 00 μA was used. The ghost potential was determined by setting the potential of the dark portion to 400 V and the potential of the exposed portion to 50 V, and measuring the potential of the dark portion after one round of the photosensitive member after exposure. Under this condition, the light amount of the static elimination light is set to 1 [lux. sec] to 11 [lux. sec]
, And the charging ability and ghost potential at each light amount of the static elimination light were determined. FIG. 5 shows the result in this case. As the amount of static elimination light was increased, the potential appearing as a ghost was reduced, but the charging ability was reduced.

Next, the light amount of the static elimination light is set to 4 lux. sec, and the wavelength of the image exposure was changed. 56 light sources for image exposure
The ghost potential was measured using LED heads of 5,610,630,660,700 nm. Fig. 6 shows the results.
Shown in As can be seen from FIG.
When the LEDs 610, 630, and 660 are used, the ghost potential is lower than when a 700 nm LED head is used as the image exposure light source.

(Experimental Example 2) A photoreceptor manufactured in the same manner as in Experimental Example 1 was charged by using the same image forming apparatus as in Experimental Example 1 for charging ability.
The ghost memory rank was evaluated. Note that a semiconductor laser of 635, 650, 680, or 788 nm is used for image exposure, an LED of 680 nm is used for static elimination light, and the light amount is 4 [lux. sec]. Under these conditions, the result of obtaining the ghost potential at each image exposure wavelength is shown in FIG.
Shown in As is apparent from FIG.
When the semiconductor laser of No. 650 is used, the ghost potential is low.

As can be seen from Experimental Examples 1 and 2, it was found that the ghost memory was improved by using an image exposure light source that minimized the value of the pre-charging light memory with respect to the sensitivity. As a result, the amount of pre-dew light can be reduced as compared with the related art, and the charging ability can be increased.

In Experimental Examples 3 to 9, the photosensitive members manufactured in the same manner as in Experimental Example 1 were evaluated using the same image forming apparatus as in Experimental Example 1. The following describes each experiment.

(Experimental Example 3) The correlation between the potential unevenness in the dark part and the peak wavelength of the static elimination light was examined. The potential unevenness was obtained by measuring the surface potential of the photoreceptor, and taking the difference between the maximum value and the minimum value within the measurement range. In this experimental example, measurement was performed at five points in the generatrix direction of the photoconductor, the respective circumferential distributions were added, and the difference between the maximum value and the minimum value of the surface potential over the entire surface of the photoconductor was defined as potential unevenness. FIG. 8 shows the dependence of the potential unevenness on the wavelength of the static elimination light when the charging potential is adjusted to 400V. Emission wavelength of 680nm
When it becomes larger, the potential unevenness tends to increase rapidly. Also, as the wavelength becomes smaller,
The potential unevenness gradually increased. As a result, the wavelength of the charge removal exposure is 600 nm or more and 680 nm or less, more preferably 63 nm or less.
It has been found that it is preferable to use a static elimination exposure of 0 nm or more and 680 nm or less.

(Experimental Example 4) The correlation between the potential unevenness in the dark part and the peak half width of the charge eliminating light was examined. An experiment was performed by using a halogen lamp as a light source for removing static electricity, using a spectroscope and a slit, and changing the wavelength and the half width. FIG. 10 shows the potential unevenness when the charging potential is adjusted to 400 V as a parameter of the peak wavelength of the charge removing light. As is apparent from the figure, the potential unevenness depends on the peak half width, and the potential unevenness increases as the peak half width increases. Peak wavelength of static elimination light is 7
In the case of 00 nm, the tendency appears most remarkably,
When the half width is larger than 50 nm, the potential unevenness increases rapidly. The peak wavelength is 660 nm, 560 n
In the case of m, when the half width is larger than 70 to 80 nm, the potential unevenness increases. From these results, it was found that good results with respect to potential unevenness were obtained when the peak half width was set to 50 nm or less regardless of the peak wavelength.

Next, an LED having the same peak wavelength of light emission and different peak half widths, and a laser (having a half width of 0n)
(plotted as m). The result is shown in FIG. As is apparent from the figure, also in this case, the same characteristics as those in FIG.
It was found that good results can be obtained with respect to the potential unevenness when it is less than m.

(Experimental Example 5) The potential unevenness in the dark area was examined by changing the moving speed of the photosensitive member surface.
The static elimination light used was an LED having a peak wavelength of 700 nm or 600 nm, an equal peak wavelength, and a different peak half width. The ratio of the potential unevenness when using the narrowest LED (half-width 20 nm) to the potential unevenness when using the LED having the widest half-width (half-width 90 nm) is defined as a ratio, and defined as the potential unevenness improvement ratio. FIG. 12 shows a graph plotted against the moving speed of the photoconductor surface. From this figure, it can be seen that the effect of improving the potential unevenness by reducing the peak half-value width of the charge removal light varies depending on the moving speed of the photoconductor surface. The moving speed of the photoconductor surface is
In the range of 200 to 600 mm / sec, it was found that the potential unevenness improving effect was particularly good.

(Experimental Example 6) The influence of the charge removal exposure on the ghost was evaluated. The primary current was kept constant at 1000 μA, and the light amounts of the static elimination light sources of each wavelength were matched so that the charging ability was 400 V. A laser light source of 650 nm was used as an image exposure light source, and the exposure portion potential was adjusted to 50 V and the contrast potential was adjusted to 350 V. FIG. 9 shows the ghost potential when the wavelength of the static elimination light is changed at this time. It has been found that ghosts are improved when static elimination light of 600 nm or more and 680 nm or less is used as static elimination light.

(Experimental Example 7) The correlation between the potential unevenness in the bright part and the peak half width of the image exposure light source was examined.
An experiment was performed using a halogen lamp as an image exposure light source, and using a spectroscope and a slit while changing the wavelength and the half width. In addition, the neutralizing light has a peak wavelength of 660 nm,
An LED having a peak half width of 30 nm was used. FIG. 13 shows the potential unevenness when the potential is adjusted to 50 V by charging and image exposure using the peak wavelength of image exposure as a parameter. As is apparent from the figure, the potential unevenness depends on the peak half width, and the potential unevenness increases as the peak half width increases. When the peak wavelength of the image exposure is 700 nm, the tendency is most remarkable, and when the half width is larger than 50 nm, the potential unevenness rapidly increases. When the peak wavelength is 660 nm, 63
In the case of 0 nm, when the half width is larger than 70 to 80 nm, the potential unevenness increases. From these results, it was found that good results with respect to potential unevenness were obtained when the peak half width was set to 50 nm or less regardless of the peak wavelength.

Next, a similar experiment was performed using an LED having the same peak wavelength of light emission and different peak half widths as an image exposure light source, and a laser (plotted with a half width of 0 nm). The result is shown in FIG. As is clear from the drawing, in this case also, the same characteristics as those in FIG. 13 are shown, and it is found that a good result with respect to the potential unevenness can be obtained when the peak half width is set to 50 nm or less.

(Experimental Example 8) The potential unevenness in the bright part was examined by changing the moving speed of the photosensitive member surface.
The image exposure uses an LED having a peak wavelength of 700 nm or 660 nm, each having the same peak wavelength, and a different peak half-value width.
An LED having a peak half width of 30 nm was used. The ratio of the potential unevenness when using the narrowest LED (half-width 20 nm) to the potential unevenness when using the LED having the widest half-width (half-width 90 nm) is defined as a ratio, and defined as the potential unevenness improvement ratio. FIG. 15 shows a graph plotted against the moving speed of the photoconductor surface. From this figure, it can be seen that the effect of improving the potential unevenness by reducing the peak half width of image exposure varies depending on the moving speed of the photoconductor surface. It was found that the effect of improving the potential unevenness was particularly good when the moving speed of the photoconductor surface was in the range of 200 to 600 mm / sec.

(Experimental Example 9) The correlation between the potential unevenness in the bright part, the charge eliminating light, and the peak half width of image exposure was examined. LEDs with peak wavelengths of 700 nm and 680 nm, respectively, are used as the light source for removing static electricity and the light source for image exposure.
Experiments were performed using a spectroscope and a slit while changing the half width of each light source. FIG. 16 shows potential unevenness when the potential is adjusted to 50 V by charging and image exposure.
The peak half width of the static elimination light is shown as a parameter.
As is apparent from the figure, the bright portion potential unevenness depends on the peak half width of the image exposure, and even when the peak half width of the static elimination light at which the unevenness becomes largest is 90 nm, the peak half width of the image exposure is 50 nm. By setting the value below, the potential unevenness is improved. Further, the peak half width of the charge removing light is set to 50 n.
In the case of m and 30 nm, the potential unevenness is improved as compared with the case of 90 nm, so that the dependence of the charge elimination light peak half width is also confirmed. From the above results, the potential unevenness in the bright part depends on the peak half width of the charge eliminating light and the peak half width of the image exposure, respectively, and either half width is 5%.
It was found that when the thickness was 0 nm or less, good results were obtained with respect to the potential unevenness. Further, it has been found that when both half-value widths are set to 50 nm or less, it is particularly improved.

[0059]

EXAMPLES (Example 1) An image of a photosensitive member manufactured in the same manner as in Experimental Example 1 was evaluated using the image forming apparatus used in Experimental Example 1. A semiconductor laser having a wavelength of 635 nm was used as an image exposure light source, a semiconductor laser having a wavelength of 650 nm was used as a charge removing light, and the photosensitive member was rotated at a speed of 200 mm / sec. At this time, sufficient charging ability effective for image formation was obtained. Next, the dark part potential is set to 400 V, and the bright part potential is set to 50 V.
The evaluation was performed using the image set in. Document images include a solid white document, a solid black document (Canon test chart, part number FY9-9073), a halftone document (Canon test chart, part number FY9-9042), and a ghost document (Canon test chart, FY9-). 904
FY9-9042 is placed on top of 0), 0.
5 mm grid paper was used. Table 2 shows the results. In each case, good images were obtained. In particular, ghosts were hardly recognized in the ghost image, and density unevenness was hardly recognized, and the image was very good.

Example 2 An image of a photosensitive member manufactured in the same manner as in Experimental Example 1 was evaluated using the image forming apparatus used in Experimental Example 1. A semiconductor laser having a wavelength of 650 nm is used as an image exposure light source, and a peak wavelength of 660 n is used as static elimination light.
m, an LED with a peak half-value width of 30 nm, and a photoreceptor of 2
It rotated at a speed of 50 mm / sec. At this time, sufficient charging ability effective for image formation was obtained. Next, the same evaluation as in Example 1 was performed. Table 2 shows the results. In each case, good images were obtained. In particular, ghosts were hardly recognized in the ghost image, and density unevenness was hardly recognized, which was very good.

(Comparative Example 1) An image of the photoreceptor manufactured in the same manner as in Experimental Example 1 was evaluated using the image forming apparatus used in Experimental Example 1. A semiconductor laser having a wavelength of 788 nm is used as an image exposure light source, and a peak wavelength of 660 n is used as static elimination light.
m, an LED with a peak half-value width of 30 nm, and a photoreceptor of 2
It rotated at a speed of 50 mm / sec. At this time, sufficient charging ability effective for image formation was obtained. Next, the same evaluation as in Example 1 was performed. Table 2 shows the results. However, a ghost was clearly confirmed in the ghost image, and a good image was not obtained.

Example 3 Image evaluation was performed on the photosensitive member manufactured in the same manner as in Experimental Example 1 using the image forming apparatus used in Experimental Example 1. A semiconductor laser having a wavelength of 650 nm is used as an image exposure light source, and a halogen lamp is used as a charge removing light.
The spectrum is divided so that the peak half-value width becomes 40 nm, and the photoreceptor is 35
It rotated at a speed of 0 mm / sec. At this time, sufficient charging ability effective for image formation was obtained. Next, the same evaluation as in Example 1 was performed. Table 2 shows the results. In each case, good images were obtained. In particular, ghosts were hardly recognized in the ghost image, and density unevenness was hardly recognized, and the image was very good.

Example 4 Image evaluation was performed on a photosensitive member manufactured in the same manner as in Experimental Example 1 using the image forming apparatus used in Experimental Example 1. A semiconductor laser having a wavelength of 650 nm was used as an image exposure light source, and a peak wavelength of 680 nm was used for static elimination light.
An LED having a peak half width of 90 nm was used, and the photoconductor was 350 nm.
It rotated at a speed of mm / sec. At this time, sufficient charging ability effective for image formation was obtained. Next, the same evaluation as in Example 1 was performed. The results are shown in Table 2. In each case,
An image with almost no problem was obtained. In particular, ghosts were hardly observed in the ghost image, which was very good, but density unevenness was slightly observed.

Example 5 Image evaluation was performed on a photosensitive member manufactured in the same manner as in Experimental Example 1 using the image forming apparatus used in Experimental Example 1. The image exposure light source has a peak wavelength of 610n.
m, an LED head having a peak half-value width of 35 nm, and a neutralizing light having a peak wavelength of 610 nm and a peak half-value width of 35 nm
And the photoreceptor was rotated at a speed of 450 mm / sec. At this time, sufficient charging ability effective for image formation was obtained. Next, the same evaluation as in Example 1 was performed. Table 2 shows the results. In each case, good images were obtained. In particular, ghosts were hardly recognized in the ghost image, and density unevenness was hardly recognized, and the image was very good.

Example 6 Image evaluation was performed on a photosensitive member manufactured in the same manner as in Experimental Example 1 using the image forming apparatus used in Experimental Example 1. A halogen lamp was used as an image exposure light source, and the peak wavelength was 680 n using a spectroscope and a slit.
m, and a peak half-value width of 40 nm, and the charge eliminating light is L having a peak wavelength of 680 nm and a peak half-value width of 45 nm.
Using the ED, the photoconductor was rotated at a speed of 360 mm / sec. At this time, sufficient charging ability effective for image formation was obtained. Next, the same evaluation as in Example 1 was performed. Table 2 shows the results. In each case, good images were obtained.
In particular, ghosts can hardly be confirmed in the ghost image,
In addition, density unevenness could hardly be confirmed, and it was very good.

Example 7 Image evaluation was performed on the photosensitive member manufactured in the same manner as in Experimental Example 1 using the image forming apparatus used in Experimental Example 1. The image exposure light source has a peak wavelength of 680 n.
m, an LED head having a peak half width of 90 nm is used, and a peak wavelength of 680 nm and a peak half width of 45 nm are used for static elimination light.
And the photoreceptor was rotated at a speed of 360 mm / sec. At this time, sufficient charging ability effective for image formation was obtained. Next, the same evaluation as in Example 1 was performed. The results are shown in Table 2. In each case, an image having almost no problem was obtained. In particular, almost no ghost was observed in the ghost image, which was very good. However, density unevenness was slightly observed.

Example 8 Image evaluation was performed on a photosensitive member manufactured in the same manner as in Experimental Example 1 using the image forming apparatus used in Experimental Example 1. The image exposure light source has a peak wavelength of 610n.
m, an LED head having a peak half width of 35 nm was used, a semiconductor laser having a wavelength of 635 nm was used for static elimination light, and the photosensitive member was rotated at a speed of 550 mm / sec. At this time, sufficient charging ability effective for image formation was obtained. Next, the same evaluation as in Example 1 was performed. Table 2 shows the results. In each case, good images were obtained. In particular, ghosts were hardly recognized in the ghost image, and density unevenness was hardly recognized, and the image was very good.

Example 9 Using the image forming apparatus used in Example 1, an image evaluation was performed on the photosensitive member manufactured in the same manner as in Example 1. A semiconductor laser having a wavelength of 650 nm is used as an image exposure light source, and an LED having a peak wavelength of 660 nm and a peak half-value width of 30 nm is used as static elimination light.
It rotated at a speed of m / sec. At this time, sufficient charging ability effective for image formation was obtained. Next, the same evaluation as in Example 1 was performed. Table 2 shows the results. In each case,
An image of a level with almost no problem was obtained. In particular, in the ghost image, ghost was hardly observed and the image was good, but density unevenness was slightly observed.

[0069]

[Table 2]

[0070]

According to the present invention, the ghost memory and the potential non-uniformity can be improved even under the conditions of high speed and downsizing, and the electrophotographic method has a high chargeability.
An electrophotographic device can be provided.

In particular, it is possible to provide an electrophotographic process in which ghost memory and potential unevenness are improved, and phenomena such as ghost and density unevenness hardly appear on an image.

When a semiconductor laser is used as the image exposure light source, the spot diameter can be reduced, and a higher quality image can be realized.

[Brief description of the drawings]

FIG. 1 is a graph plotting an optical memory of an a-Si photoreceptor at a unit contrast potential with respect to each wavelength, which is used for obtaining an appropriate value of a wavelength for image exposure according to the present invention.

FIG. 2 is a graph plotting the sensitivity of an a-Si photosensitive member with respect to each wavelength, with the sensitivity being set to 400 V for a dark part potential, 200 V for a light part potential, 400 V for a dark part potential, and 50 V for a light part potential. These values are described.

FIG. 3A is a graph in which values of an optical memory generated at a constant light amount of an a-Si photosensitive member are plotted with respect to each wavelength.
This is a case where the amount of exposure light is changed. b)
Is a graph in which the value of the optical memory generated at a constant light amount of the a-Si photosensitive member is plotted with respect to each wavelength, in which the time (unit: second) from exposure to charging is changed.

FIGS. 4A to 4D are schematic structural views for explaining a layer structure of a photoreceptor for an image forming apparatus of the present invention.

FIG. 5 is a 680 nm LED for neutralizing light and 70 for image exposure.
The graph shows the relationship between the charging ability when using a 0 nm LED head and the ghost potential measured by setting the dark part potential to 400 V and the bright part potential to 50 V with the amount of static elimination light. is there.

FIG. 6 is a graph showing a ghost potential with respect to each image exposure wavelength when an LED is used as an image exposure light source.

FIG. 7 is a graph showing a ghost potential with respect to each image exposure wavelength when a semiconductor laser is used as an image exposure light source.

FIG. 8 is a graph showing the dark portion potential unevenness with respect to the wavelength of the static elimination exposure when the dark portion potential is set to 400V.

FIG. 9 is a graph showing a ghost potential with respect to each neutralization light wavelength using a semiconductor laser of 650 nm as an image exposure light source.

FIG. 10 is a graph showing a dark portion potential unevenness with respect to a peak half value width of static elimination exposure when a dark portion potential is set to 400 V, in which a peak half value width is changed by a spectroscope and a slit.

FIG. 11 is a graph showing the dark portion potential unevenness with respect to the peak half width of the static elimination exposure when the dark portion potential is set to 400 V, which uses LED elements having different peak wavelengths and peak half widths, and a laser. is there.

FIG. 12 shows a dark area potential unevenness improvement rate (peak half-value width is 20).
Potential unevenness / peak half-width when using nm LED is 90 nm
4 is a graph showing the photoreceptor surface speed dependency of potential unevenness when using an LED.

FIG. 13 is a graph showing unevenness of the light portion potential with respect to the peak half value width of image exposure when the light portion potential is set to 50 V, in which the peak half value width is changed by a spectroscope and a slit.

FIG. 14 is a graph showing the unevenness of the light portion with respect to the peak half width of image exposure when the light portion potential is set to 50 V.
And a laser.

FIG. 15 shows a bright portion potential unevenness improvement ratio (peak half width is 20).
Potential unevenness / peak half-width when using nm LED is 90 nm
4 is a graph showing the photoreceptor surface speed dependency of potential unevenness when using an LED.

FIG. 16 is a graph showing the light-part potential unevenness with respect to the peak half-value width of image exposure when the light-part potential is set to 50 V, and plots the peak half-value width of charge removal exposure as a parameter.

FIG. 17 shows a half width described in the present invention.

FIG. 18 is a schematic diagram for explaining the electrophotographic method and apparatus of the present invention.

[Explanation of symbols]

 Reference Signs List 500 photoconductor 501 support 502 photosensitive layer 503 photoconductive layer 504 surface layer 505 charge injection blocking layer 507 charge generation layer 508 charge transport layer 601 electrophotographic photoconductor 602 main charger 603 developer 604 transfer / separation charger 605 cleaning device 606 Main static elimination light source 607 Exposure equipment

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaya Kawata 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Tetsuya Karaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Non-corporation (72) Inventor Yuji Nakayama 3-30-2 Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (72) Inventor Takaaki Kaya 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. F term (reference) 2H027 DD09 EA02 EA10 ED02 ED06 ED26 EE03 EE06 2H035 AA09 AA10 AB03 AC02 2H068 DA23 FB07 FB08 FC05 2H076 AB05 AB42 DA01 DA11 DA37

Claims (38)

[Claims] 1. An electrophotographic method for forming an image by at least charge elimination, charging, latent image exposure, development and transfer,
The photosensitive element as a recording element, at least the light receiving layer is made of amorphous, and, for image exposure for forming a latent image, using light in which the peak wavelength in the emission spectrum has the minimum value of the optical memory with respect to the unit contrast potential, In addition, the half width of the peak in the emission spectrum is 50 nm for the charge removal exposure.
An electrophotographic method using the following light. 2. The moving speed of the photosensitive member surface is 200 m
2. The speed is not less than m / sec and not more than 600 mm / sec.
The described electrophotographic method. 3. A peak wavelength of 600 nm for the charge-removal exposure.
3. The electrophotographic method according to claim 1, wherein light having a wavelength of at least 680 nm is used. 4. A peak wavelength of 600 nm for the image exposure.
3. The electrophotographic method according to claim 1, wherein light having a wavelength of 660 nm or less is used. 5. A peak wavelength of 600 nm for the charge-removal exposure.
3. The electrophotographic method according to claim 1, wherein a light having a peak wavelength of 600 nm or more and 660 nm or less is used for the image exposure. 6. The electrophotographic method according to claim 1, wherein the exposure light source is a laser or an LED. 7. The electrophotographic method according to claim 1, wherein the photoconductor is made of amorphous silicon. 8. An electrophotographic method for forming an image by at least static elimination, charging, latent image exposure, development and transfer,
The photoreceptor as a recording element has at least a light-receiving layer made of an amorphous material. During image exposure for forming a latent image, a peak wavelength in an emission spectrum has a minimum value of an optical memory with respect to a unit contrast potential, and a peak half width is 50 nm or less. An electrophotographic method characterized by using light that is: 9. The moving speed of the photosensitive member surface is 200 m
9. The speed is not less than m / sec and not more than 600 mm / sec.
The described electrophotographic method. 10. The image exposure has a peak wavelength of 600 n.
The electrophotographic method according to claim 8, wherein light having a wavelength of m to 660 nm is used. 11. The electrophotographic method according to claim 8, wherein the exposure light source is a laser or an LED. 12. The electrophotographic method according to claim 8, wherein the photoconductor is made of amorphous silicon. 13. An electrophotographic method for forming an image by at least static elimination, charging, latent image exposure, development and transfer, wherein a photosensitive element as a recording element has at least a light-receiving layer made of amorphous In the image exposure, light having a peak wavelength in the emission spectrum with respect to the unit contrast potential, the value of the optical memory is minimized, and the light having a peak half width of 50 nm or less is used. An electrophotographic method using the following light. 14. The moving speed of the photoconductor surface is 200
14. The electrophotographic method according to claim 13, wherein the speed is not less than mm / sec and not more than 600 mm / sec. 15. A peak wavelength of 600 n for the static elimination exposure.
13. The light according to claim 13, wherein light having a wavelength of not less than m and not more than 680 nm is used.
4. The electrophotographic method according to 4. 16. The image exposure has a peak wavelength of 600 n.
13. The light according to claim 13, wherein light having a wavelength of not less than m and not more than 660 nm is used.
4. The electrophotographic method according to 4. 17. A peak wavelength of 600 n for the charge-removal exposure.
15. The electrophotographic method according to claim 13, wherein a light having a peak wavelength of 600 nm or more and 660 nm or less is used for the image exposure. 18. The electrophotographic method according to claim 13, wherein the exposure light source is a laser or an LED. 19. The electrophotographic method according to claim 13, wherein said photoconductor is made of amorphous silicon. 20. An electrophotographic apparatus for forming an image by at least static elimination, charging, latent image exposure, development, and transfer, wherein a photosensitive member as a recording element has at least a light-receiving layer made of an amorphous material and a latent image. In the image exposure for formation, light whose peak wavelength in the emission spectrum has the minimum value of the optical memory with respect to the unit contrast potential is used, and the half width of the peak in the emission spectrum is 50 in the exposure for static elimination.
An electrophotographic apparatus using light having a wavelength of not more than nm. 21. The moving speed of the photoconductor surface is 200
21. The electrophotographic apparatus according to claim 20, which is not less than mm / sec and not more than 600 mm / sec. 22. A peak wavelength of 600 n for the static elimination exposure
21. The light according to claim 20, wherein light having a wavelength of at least m and at most 680 nm is used.
2. The electrophotographic apparatus according to 1. 23. A peak wavelength of 600 n for the image exposure.
21. The light according to claim 20, wherein light having a wavelength of at least m and at most 660 nm is used.
2. The electrophotographic apparatus according to 1. 24. A peak wavelength of 600 n for the charge elimination exposure.
22. The electrophotographic apparatus according to claim 20, wherein light having a peak wavelength of 600 nm or more and 660 nm or less is used for the image exposure. 25. The electrophotographic apparatus according to claim 20, wherein the exposure light source is a laser or an LED. 26. The electrophotographic apparatus according to claim 20, wherein said photoconductor is made of amorphous silicon. 27. An electrophotographic apparatus for forming an image by at least static elimination, charging, latent image exposure, development, and transfer, wherein a photosensitive member as a recording element has at least a light-receiving layer made of amorphous An electrophotographic apparatus, wherein light having a peak wavelength in an emission spectrum, a value of an optical memory with respect to a unit contrast potential, and a peak half-value width of 50 nm or less is used for image exposure. 28. The moving speed of the photoconductor surface is 200
28. The electrophotographic apparatus according to claim 27, wherein the speed is not less than mm / sec and not more than 600 mm / sec. 29. A peak wavelength of 600 n for the image exposure.
28. The light according to claim 27, wherein light having a wavelength of at least m and at most 660 nm is used.
9. The electrophotographic apparatus according to 8. 30. The electrophotographic apparatus according to claim 27, wherein said exposure light source is a laser or an LED. 31. The electrophotographic apparatus according to claim 27, wherein the photoconductor is made of amorphous silicon. 32. In an electrophotographic process in which an image is formed by at least static elimination, charging, latent image exposure, development and transfer, a photosensitive element as a recording element has at least a light-receiving layer made of amorphous In image exposure, the peak wavelength in the emission spectrum is such that the value of the optical memory with respect to the unit contrast potential is minimal, and the half width of the peak is 50 nm.
An electrophotographic apparatus, wherein the following light is used, and light having a half-width of a peak in an emission spectrum of 50 nm or less is used for exposure for static elimination. 33. A moving speed of the photoconductor surface is 200
33. The electrophotographic apparatus according to claim 32, wherein the speed is from mm / sec to 600 mm / sec. 34. A peak wavelength of 600 n for the charge-removal exposure.
34. The light of claim 32 or 3, wherein light having a wavelength of not less than m and not more than 680 nm is used.
3. The electrophotographic apparatus according to 3. 35. A peak wavelength of 600 n for the image exposure.
32. The light of claim 32, wherein light having a wavelength of at least m and at most 660 nm is used.
3. The electrophotographic apparatus according to 3. 36. A peak wavelength of 600 n for the charge elimination exposure.
34. The electrophotographic apparatus according to claim 32, wherein light having a peak wavelength of 600 nm or more and 660 nm or less is used for the image exposure. 37. The electrophotographic apparatus according to claim 32, wherein the exposure light source is a laser or an LED. 38. The electrophotographic apparatus according to claim 32, wherein said photoconductor is made of amorphous silicon.