JPH02235084A - Image forming device - Google Patents

Abstract

PURPOSE:To miniaturize the constitution of a device and to form a good-quality image by controlling the light quantity of the light source of an incorporated photoirradiation device in accordance with the exposed light quantity of an organic photoconductor being a photosensitive body. CONSTITUTION:The light quantity of an exposing lamp 18a is controlled by a controller 33 in accordance with the density of an original 17 detected by the automatic exposure sensor 30 of a control means 31 and a latent image corresponding to the image of the original 17 is formed on the photosensitive drum 10 being the organic photocondoctor. In accordance with the exposed light quantity, the light quantity of the light source 24 which forms the incorporated photoirradiation device with a slit forming device 26 which irradiates the organic photoconductor from a back surface is controlled through a delay device 36, etc. The transfer efficiency of a transfer charger 21 through the slits 27 and 28 is enhanced and an statically eliminated exposing time just before performing uniform electrostatic charging by means of an electrostatic charger 14 is sufficiently conserved in substance. Then, the constitution of the device is miniaturized, the optical fatigue of the photoconductor is reduced and the good-quality image is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an improvement in an image forming apparatus such as an electrophotographic apparatus that is small and maintains good photoconductor characteristics.

(Prior Art) In image forming devices such as copying machines and laser printers, static electricity is generated on the photoreceptor. l! An image is obtained by forming an electrostatic image, and then developing this electrostatic image with a developer to make it visible, and then transferring it to a sheet of paper or the like.

In recent years, photoreceptor materials suitable for such image forming apparatuses have been developed because they are non-polluting and do not require recycling.
Photoreceptors in which a low-cost organic photoconductor is coated on a drum-shaped or belt-shaped conductive support are increasingly being used. Conventionally, this organic photoconductor has the drawbacks of lower sensitivity than inorganic materials such as selenium [Sel], and furthermore, its characteristics deteriorate quickly and its lifespan is short.
Although it has only been applied to low-speed and low-cost image forming apparatuses, recently, the sensitivity and lifespan have been improved by selecting materials and improving the layer structure, and the scope of its application has been expanded.

However, in recent years, in image forming apparatuses that use such organic photoconductors as photoconductors, the drum-shaped photoconductor has been required to be downsized to meet the demand for smaller main bodies, and the diameter of the photoconductor has become smaller. has been done.

Moreover, since each image forming means for forming an image on the photoreceptor is all provided around the photoreceptor, the time required for each image forming process by each image forming means is shortened as the diameter of the photoreceptor is reduced. This poses a problem in that the shortening of charging time and neutralizing time causes a decrease in surface potential and an increase in residual potential, resulting in a decrease in image quality. In particular, with static eliminators, the static neutralization time is not sufficient, and the surface potential cannot be sufficiently neutralized to O [V] before reaching the next charging process, resulting in an increase in the residual potential. This problem arises and has a negative effect on the image. Additionally, in order to eliminate these problems, devices have been developed that increase the voltage applied to the charger and increase the light intensity of the static elimination lamp to raise the surface potential, and even completely remove the residual potential. However, in such devices, since the amount of light irradiated onto the photoreceptor by the static elimination lamp is strong, the photoreceptor deteriorates rapidly, such as an increase in residual potential due to optical fatigue of the photoreceptor and a decrease in surface potential. ball,
Continuous image formation causes another problem in that the image quality is significantly degraded.

(Problems to be Solved by the Invention) As described above, as image forming apparatuses that use organic photoconductors as photoconductors become smaller, conventionally, image forming processes using image forming means provided around a drum-shaped photoconductor have been reduced. There is not enough time to Therefore, there is a problem that image quality deteriorates because a sufficient surface potential is not obtained or residual potential is not eliminated. Furthermore, in order to compensate for the reduction in image forming process time, the output of the static elimination lamp is increased and the amount of static elimination light is increased, which increases optical fatigue on the photoconductor, accelerates deterioration of the photoconductor due to repeated copying, and significantly reduces image quality. This creates a new problem of being exposed.

Therefore, in order to eliminate the above-mentioned drawbacks, the present invention aims to reliably eliminate the residual potential regardless of the miniaturization of the drum-shaped photoreceptor, and furthermore, even when the image forming process is repeated.
An object of the present invention is to provide an image forming apparatus capable of obtaining good images without causing optical fatigue on a photoreceptor.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above problems, the present invention provides a photoconductor supported on a drum-shaped conductive support having translucency, and a photoconductor supported by a drum-shaped conductive support having translucency. In order to form an image, at least the photoconductor is irradiated with image information and an electrostatic charge is generated. an exposure device that forms a 4F image;
A light irradiation device that irradiates light from the back surface of the photoconductor inside the conductive support, and further an image forming means that has a control means that controls the amount of light emitted from the light source of the light irradiation device according to the amount of exposure light of the exposure device. It shall be established.

(Function) According to the present invention, by the above means, sufficient image forming process time can be obtained in each image forming means regardless of the diameter of the drum-shaped photoreceptor. Reliably prevents the increase in residual charge without increasing the
In addition to improving image quality, the amount of light can be adjusted to the minimum necessary, reducing fatigue at the tip of the photoreceptor to the minimum necessary, preventing deterioration in image quality, and making it possible to repeat the image forming process. It is something to do.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a schematic explanatory diagram showing a part of the image forming apparatus, and 1o is a diameter 5 (l [mm
] This is a photoreceptor consisting of a drum-shaped conductive support l1 and an organic photoconductor 12 coated so as to be supported by the conductive support 11. Image forming means 13 are provided around the surface of the photoreceptor 10 and further inside the photoreceptor 10 .

Among the image forming means 13, a charging device l4 to which a voltage of -6 [kV] is applied, an original 1 placed on an original platen 16,
Exposure lamp 18a consisting of a halogen lamp that irradiates
an exposure device 18 that irradiates a document image, which is image information, from the surface of the organic photoconductor 12, and a magnet roller 20a.
A developing device 20, a transfer charger 21, a peeling charger 22, and a cleaning device ffi'2g to which a developing bias of about -200 [V] is applied are sequentially provided around the photoreceptor 10. Note that 18b is a first lamp regulator that adjusts the output so that the standard exposure light amount of the exposure lamp 18H is 100 [1ux]. On the other hand, among the 1,000 image forming stages 13, a light source 24 consisting of a standard light Q30 (1 uxl halogen lamp) is provided inside the photoreceptor 10 for performing pre-transfer exposure and eliminating static electricity. Furthermore,
A drum-shaped fixed slit forming device 2B that is coaxial with the photoreceptor 10 is provided around the outer periphery of the light source 24.

The slit forming device 2B includes a first slit 27 facing the transfer charger 21, and a slit 27 having a width of about 5 mm provided between the cleaning device 23 and the charging device 14.
A second slit 28 of [III1] is formed.

The slit forming device 26 and the light source 24 constitute a light irradiation device. Note that 24a is a second lamp regulator that adjusts its output so that the standard light amount of the light source 24 is 30[1uxl]. Furthermore, 30 is an automatic exposure sensor that measures the density of the original document 17. Next, FIG. 2 shows a control means 31, which has a controller 33 into which the detection result of the automatic exposure sensor 30 is inputted via an A/D converter 32. Then, the output from this controller 33 causes the first lamp regulator 18b to
is adjusted through the D/A converter 34, and the output of the second lamp regulator 24a is adjusted through the D/A converter 34 and the delay device 36, respectively.

Next, we will discuss the effect. When a copy button (not shown) is turned on to start copying, the photoreceptor lO is rotated in the direction of arrow X, voltage is applied to the charging device 14, transfer charger 21, and peeling charger 22, and further The exposure lamp 18a and the light source 24 are turned on, and the developing device 2
0 is also started to be driven. Then, as the photoreceptor IO rotates, the charging device l4 uniformly applies a voltage of about -650 [V] to the photoreceptor IO.
is charged with electricity. Next, the image of the original 17 is irradiated onto the photoreceptor IO by the exposure device l8, but during this exposure, the image of the original 17 is determined by the automatic exposure sensor 30. The amount of exposure light from the exposure lamp 18a and the amount of light from the light source 24 of the light irradiation device are controlled according to the measurement result of the degree a. That is, if the document density is within the standard range, the controller 33 outputs to the first ramp regulator 18b1 and the second ramp regulator 24a that the current state is maintained.

The exposure lamp 18a is held at loo [1ux], and the light source 24 is held at 30 [1ux] by the delay device 36 when the photoreceptor 10 reaches the second slit 28. When the automatic exposure sensor 30 detects that the original 17 is thin while scanning the original 17, the controller 33 sends an output signal to increase the output voltage of each lamp regulator 18b, 24a. This causes the first lamp regulator ta
The second lamp regulator 24a immediately adjusts its output to increase the amount of exposure light from the exposure lamp 18a, while the second lamp regulator 24a adjusts its output after a certain period of time has elapsed using the delay device 36. Furthermore, if it is detected that the original 17 is dark during original scanning, the controller 33 will conversely send an output signal to each lamp regulator 18b, 24a to reduce the output voltage. In this way,
In the exposure device 18, an electrostatic latent image is formed on the photoreceptor 10 while adjusting the amount of exposure light depending on the density of the original document 17.

After this, the photoreceptor lO is developed by the developing device 20 to form a toner image. Next, the photoreceptor 10 reaches the transfer charger 2l, and a sheet of paper (
At this time, the photoreceptor 10 is given an alternating current charge from its surface by the transfer charger 21, and is also charged by the light source 24 through the first slit 27. Light is irradiated from the back side, increasing the transfer efficiency. And the sheet paper is peeled off charger 2
2, it is peeled off from the photoconductor lO, and then transferred to the fixing device (
(not shown), and image formation is completed. On the other hand, after peeling off the sheet paper, the photoreceptor 10 is removed by a cleaning device 23.
After residual toner is removed by the light source 24, the amount of light emitted from the second slit 28 is adjusted according to the amount of exposure light.
is exposed from the back side to eliminate static electricity, and the surface potential becomes almost 0.
[■], and the next copy is possible.

In this way, the exposure lamp 18 is adjusted according to the density of the original 17.
When copying was repeated while adjusting a and the light source 24, good images could be obtained without any deterioration in image quality since the light fatigue of the photoreceptor was small, and furthermore, the light fatigue of the photoreceptor was reduced. Even with 20 copies, I was able to obtain almost the same image quality as the initial version.

With the configuration described above, the drum-shaped photoreceptor 1
Despite the miniaturization of 0, during transfer and static elimination,
Since the light source 24 housed inside the photoreceptor 10 can irradiate the photoreceptor 10 with sufficient light over time through the slits 27 and 28, the static electricity on the photoreceptor IO can be sufficiently removed without increasing the amount of light from the light source 24. , it is possible to prevent an increase in residual potential and obtain a good copy image. Furthermore, compared to the conventional static elimination lamp, which had a large light intensity of about 70[:ILIK],
In this embodiment, since sufficient charge removal time can be obtained, the amount of lamp light itself can be reduced to about 'AO [Iux]. Moreover, since the amount of light emitted by the light source 24 can be adjusted according to the amount of light irradiated by the exposure lamp 18a, it is possible to prevent the photoreceptor IO from being irradiated with more light than necessary. Optical fatigue can be significantly reduced, and image quality does not deteriorate even during continuous copying, making continuous copying possible. Furthermore, during transfer, the light irradiation from the first slit 27 significantly improves the transfer efficiency of the toner image, making it possible to reduce the voltage applied to the transfer charger 21.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and for example, the standard amount of light emitted from the light source of the light irradiation device may be arbitrary depending on the amount of exposure light of the exposure device or the characteristics of the photoconductor. If the exposure light amount is small, the standard light emission amount of the light source is also reduced, while if the exposure light amount is large, the standard light emission amount of the light source is also increased. Alternatively, the light sources of the light irradiation device may be individually provided at the transfer position or the static elimination position, and a slit forming device may be provided between each light source and the conductive support. More slit formation! The slit width or the slit position at the jt position is not limited either. For example, if pre-transfer exposure is not performed, only the slit for static elimination exposure may be used, or even if pre-transfer exposure is performed, the slit position may be ,
A slit may be formed at any position after development until it reaches the transfer device.For static elimination exposure, a slit may be formed at any position after transfer until it reaches the charging device. .

The charged polarity of the photoconductor may be either positive or negative.

[Effects of the Invention] As detailed above, according to the present invention, despite the miniaturization of the drum-shaped photoconductor, sufficient charge removal time can be taken during charge removal exposure, so that the light irradiation device can be used as in the conventional case. The surface potential can be reduced to almost 0 before the next charging without increasing the amount of light emitted from the light source.
[V], thereby preventing an increase in residual potential and obtaining a good image.Furthermore, it becomes possible to further downsize the photoconductor and, by extension, the image forming apparatus. In addition, since the light intensity of light irradiation equipment other than the exposure device can be adjusted to the minimum necessary level according to the exposure light intensity, it is possible to minimize optical fatigue of the photoconductor and form continuous images. becomes possible.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention, with FIG. 1 being a partially schematic explanatory diagram and FIG. 2 being a block diagram of the control means. IO...Photoreceptor, 1l...Conductive support, I2... Leading electric body 13...One image forming means, 14...Charging device, 18...Exposure device, 18a...・Exposure lab, 24...Light source, 2
G... Slit forming device, 27... First slit, 28... Second slit, 30... Automatic exposure sensor 3l... Control means, 33... Controller. Agent Patent Attorney Norio Ogo

Claims (1)

[Claims] In an image forming apparatus comprising a photoconductor supported by a drum-shaped conductive support having translucency, and an image forming means for forming an image on the photoconductor, the image forming means includes at least the above-mentioned photoconductor. an exposure device that irradiates a photoconductor with image information to form an electrostatic latent image on the photoconductor; a light irradiation device that is housed inside the conductive support and irradiates light from the back side of the photoconductor; An image forming apparatus comprising: a control means for controlling an amount of light emitted from a light source of the light irradiation device according to an amount of exposure light from the exposure device.