JPH03248185A - Image forming device - Google Patents

Abstract

PURPOSE:To speedily activate a cold cathode discharge tube and to improve image quality by irradiating the cold cathode discharge tube which forms a destaticizing lamp, with a beam. CONSTITUTION:The cold cathode discharge tube is utilized in the destaticizing lamp 33, when the beam emitted by this cold cathode discharge tube irradiates a surface of a photosensitive body drum 15, charge on this photosensitive body drum 15 surface is erased. Furthermore, when a part of the beam from an exposure part 4 is provided on the cold cathode discharge tube 33 through an optical fiber 6 as a beam irradiating means, electrons from an electrode are made easier to be scattered to speedily activate the cold cathode discharge tube. Thus, response of the cold cathode discharge tube utilized as the destaticizing lamp 33 is improved, and the copied image quality is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus applied to electronic copying machines, laser printers, and the like.

(Prior Art) A conventional image forming apparatus has a photosensitive drum as an image carrier for carrying an electrostatic latent image within the apparatus main body.
After the surface of the photoreceptor drum is uniformly charged by a charging device, the surface of the photoreceptor drum is exposed by being irradiated with light from an exposure lamp, and an electrostatic latent image is formed on the surface of the photoreceptor drum. This electrostatic latent image is developed by a developing device to form a toner image. This toner image is conveyed to a transfer device and transferred onto paper as a transfer target. When the toner image transfer process is completed, the toner remaining on the surface of the photoreceptor drum is cleaned by a cleaning device, and then the light from the static elimination lamp is irradiated onto the surface of the photoreceptor drum. Charge is erased.

By irradiating the surface of the photoreceptor drum with light from the static elimination lamp in this way, the potential on the surface of the photoreceptor drum is reduced to almost zero.
Set to bolt.

Such static elimination lamps are selected taking into account the sensitivity characteristics of the photoreceptor drum, etc. For example, a predetermined filter is added to a white light source for emitting white light, and the white light that passes through this filter is provided. or neon lamps or LEDs.

However, all of these light sources have problems in that they generate heat or cannot provide a sufficient amount of light.

Therefore, in recent years, static elimination lamps using fluorescent tubes such as cold cathode discharge tubes have been proposed.

Such a static elimination lamp using a cold cathode discharge tube can obtain a predetermined amount of light without generating heat, and therefore can reliably eliminate the electric charge on the surface of the photoreceptor drum.

(Problem to be Solved by the Invention) However, in conventional image forming apparatuses that use cold cathode discharge tubes as static elimination lamps, it takes time for the cold cathode discharge tubes to light up after the power is turned on. However, the problem was that the response was poor. In this way, due to the delay in lighting time of the cold cathode discharge tubes when the power is turned on, the charge on the surface of the photoreceptor drum is not erased sufficiently, resulting in the problem that the margins of the copied paper become smudged. had.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus that improves the quality of copied images by improving the responsiveness of a cold cathode discharge tube used as a static elimination lamp. purpose.

[Structure of the Invention] (Means for Solving the Problems) A first invention provided by the present application for achieving the above object is to transfer a transfer target to a transfer target based on an electrostatic latent image formed on the surface of a photoreceptor. an image forming means for forming an image on the surface of the photoreceptor; a cold cathode discharge tube for emitting light onto the surface of the photoreceptor on which the image formation by the image forming means has been completed to erase the electric charge on the photoreceptor; and a light irradiation means for irradiating light to the cold cathode discharge tube.

Further, a second invention provided by the present application includes an image forming means for forming an image on a transfer target based on an electrostatic latent image formed on the surface of a photoreceptor; A cold cathode discharge tube that irradiates light onto the surface of a photoreceptor to erase charges on the photoreceptor, and an optical fiber that guides light from an exposure lamp that exposes an original to the cold cathode discharge tube. It was constructed with

Furthermore, a third invention provided by the present application provides an image forming means for forming an image on a transfer target based on an electrostatic latent image formed on the surface of a photoreceptor, and an end of image formation by the image forming means. a cold cathode discharge tube that irradiates light onto the surface of a photoreceptor to erase charges on the photoreceptor; and an optical fiber that guides light from outside the casing to the cold cathode discharge tube. Configured.

(Function) In the first invention provided by the present application, an image is formed on a transfer target based on an electrostatic latent image formed on the surface of a photoreceptor.

Light from a cold cathode discharge tube is irradiated onto the surface of the photoreceptor on which image formation has been completed, thereby erasing the charges on the photoreceptor. Further, it has a light irradiation means for irradiating light to the cold cathode discharge tube, and the cold cathode discharge tube is immediately activated by the light irradiated from the light irradiation means, thereby improving the image quality.

Further, in the second and third inventions provided by the present application, an image is formed based on an electrostatic latent image formed on the surface of a photoreceptor.

Light from a cold cathode discharge tube is irradiated onto the surface of the photoreceptor on which image formation has been completed, thereby erasing the charges on the photoreceptor. It also has an exposure lamp for exposing the original or an optical fiber for guiding light from outside the housing to the cold cathode discharge tube. It is possible to reliably irradiate the cold cathode discharge tube.

(Embodiment) An embodiment of the present invention will be described in detail below with reference to the drawings.

First, the internal structure of the upper unit 1 of the image forming apparatus to which the present invention is applied will be explained with reference to FIG.

A document table 2 made of a glass plate or the like is provided above the upper unit 1 on which a document is placed. A document cover (not shown) is provided above the document table 2 so as to be openable and closable.

An exposure lamp 4 formed from a light source such as a halogen lamp is used to irradiate light onto the original, and a glue deflector 5 covers the exposure lamp 4 as a reflector that focuses the light from the exposure lamp 4 onto the original surface. It is set up like this. An optical fiber 6 is provided adjacent to the reflector 5.

An opening (not shown) is formed in the outer periphery of the reflector 5 at a portion facing the optical fiber 6, and a portion of the light from the exposure lamp 4 is applied to the optical fiber 6 through this opening. That is, the exposure lamp 4 has a light amount of more than a predetermined value, and a part of the light is given to a cold cathode discharge tube, which will be explained later, via the optical fiber 6.

The light reflected from the surface of the original enters lens 9 via mirrors 7.8a and 8b. The light passing through the lens 9 is reflected in the mirror 10a.
, 10b, 11 and the slit glass 13 to an exposure section 17 of a photoconductor drum 15 as a photoconductor.

Further, the upper unit 1 has a control panel (not shown), and this control panel is provided with a plurality of operation switches such as a copy switch.

Next, the structure of the photosensitive drum 15 and the image forming means provided around it will be explained with reference to FIG.

The photosensitive drum 15 is arranged approximately at the center of the image forming apparatus and rotates in the direction F1. Along the rotational direction of the photosensitive drum 15, a charging device 19, a blank exposure section 21, a developing device 23, a pre-transfer static elimination lamp 25, a transfer charger 2
7, a peeling charger 29, a cleaning device 31, and a static elimination lamp 33 are arranged.

The charging device 19 uniformly charges the surface of the photoreceptor drum 15. After the surface of the photoreceptor drum 15 is uniformly charged by the charging device 19, the exposure portion 17 of the photoreceptor drum 15 is irradiated with light from the exposure lamp 4, thereby exposing the photoreceptor drum 15 to light. That is, the charges on the surface of the photoreceptor drum 15 are discharged by exposure, and an electrostatic latent image is formed.

The developing device 23 includes toner as a developer, a developing roller for conveying the toner, and the like, and develops the electrostatic latent image described above to form a toner image.

A paper feeding device (not shown) is disposed diagonally to the lower right side of the developing device 23. The paper stored in this paper feeder is taken out one by one and transferred to the photosensitive drum 15 and the transfer charger 2.
7 and is conveyed to the transfer section between them.

The transfer charger 27 transfers the toner image formed on the surface of the photoreceptor drum 15 to a sheet of paper passing through the transfer section by performing corona discharge.

The peeling charger 29 peels the paper after the transfer from the photoreceptor drum 15.

The cleaning device 31 is for cleaning toner remaining on the surface of the photoreceptor drum 15.

A cold cathode discharge tube is used for the static elimination lamp 33, and when the surface of the photoreceptor drum 15 is irradiated with light emitted from the cold cathode discharge tube, the electric charge on the surface of the photoreceptor drum 15 is erased. be done. In addition, the above-mentioned pre-transfer static elimination lamp 25
Both cold cathode discharge tubes are also formed, and the amount and wavelength of the light emitted from both of these cold cathode discharge tubes are respectively set to appropriate values. Further, an optical fiber 6 as a light irradiation means is arranged near the static elimination lamp 33. This optical fiber 6 is arranged along an Oze cable (not shown) or the like, and its tip is arranged facing the cold cathode discharge tube. Therefore, part of the light from the exposure section 4 is applied to the cold cathode discharge tube via the optical fiber <6. When part of the light from the exposure lamp 4 is applied to the cold cathode discharge tube in this manner, electrons from the electrodes are more likely to fly, causing the cold cathode discharge tube to operate quickly. Further, the tip of the optical fiber 6 is arranged at a position such that the light from the exposure lamp 4 provided via the optical fiber 6 is not irradiated onto the surface of the photoreceptor drum 15.

Next, the operation will be explained with reference to FIG.

As shown in FIG. 3, when the copy switch for starting copying is turned on at time t1, a predetermined time T
1. For example, at time t3 after 0.4 seconds have elapsed, the exposure lamp 4 is turned on. When the exposure lamp 4 is turned on, part of its light is given to the cold cathode discharge tube via the optical fiber 6. As a result, the static elimination lamp 33 operates and lights up almost simultaneously with the exposure lamp 4.

Next, a predetermined time T3 after the copy switch is turned on
For example, at time t5 after 2.96 seconds have elapsed, a scanning motor for moving a scanning unit such as the exposure lamp 4 is driven. As a result, the image of the original placed on the original platen 2 is read and an image is formed. That is, after the surface of the photoreceptor drum 15 is uniformly charged by the charging device 19, light from the exposure lamp 4 that reads the surface of the document is applied to the exposure section 17. As a result, an electrostatic latent image is formed on the surface of the photoreceptor drum 15.

This electrostatic latent image is developed by a developing device 23 to form a toner image. As the photosensitive drum 15 rotates in the direction F1, the toner image is conveyed to the transfer section. At this time, a sheet of paper fed from a paper feeding device (not shown) is being conveyed to the transfer section, and the toner image is transferred onto the sheet by the transfer charger 27.

The paper to which this toner image has been transferred is placed in a peeling charger 29.
After being peeled off, it is discharged. Further, the toner remaining on the surface of the photoreceptor drum 15 is removed by a cleaning device 31.
After cleaning, the photosensitive drum 15 is irradiated with light from the static elimination lamp 33. As a result, the photoreceptor drum 1
The charge on the surface of 5 is erased. This completes one copying process. Thereafter, the copying process is performed an appropriate number of times in the same manner.

In the above embodiment, the light from the exposure lamp 4 is provided to the cold cathode discharge tube via the optical fiber 6, but the present invention is not limited to this, and may be configured using an appropriate light source. can do. For example, by arranging a light source such as an LED having a predetermined amount of light or more in the vicinity of the static elimination lamp 33, and configuring the structure so that the light from the LED is directly applied to the cold cathode discharge tube, it is possible to eliminate the need for an optical fiber. Cost reduction can be achieved. LED like this
When placing a light source such as the above in the vicinity of the static elimination lamp 33, it is necessary to place the LED in a position where the light from the LED does not irradiate the photosensitive drum 15.

Next, another embodiment of the present invention will be described with reference to FIGS. 4 and 5.

The embodiment shown in FIG. 4 includes a document feed tray 37 for feeding documents to the upper unit 1, a document discharge tray 39 for discharging documents, and a control device having various operation parts such as a copy switch. Each of the panels 41 is provided in a housing. Further, on the surface of the control panel 41, a lighting section 43 having a hole of a predetermined shape is formed. This lighting section 43 is connected to the optical fiber 6 as shown in FIG.
External light from a lighting device or the like for illuminating the room in which the image forming apparatus is installed is supplied to the cold cathode discharge tube via the lighting section 43 and the optical fiber 6.

In the embodiment described above, the lighting section 43 is provided on the surface of the control panel 41 to let in light from outside the image forming apparatus housing, but the present invention is not limited to this. The lighting section 43 can be provided at an appropriate position.

In addition, if it is configured to be connected to an appropriate light source through the lighting section 43, it is possible to easily select an arbitrary light source that is optimal for operating the cold cathode discharge tube.

[Effects of the Invention] As explained above, according to the present invention, since the configuration is such that light is irradiated to the cold cathode discharge tube forming the static elimination lamp, the cold cathode discharge tube can be operated quickly and the image quality can be improved. can be improved.

Furthermore, since the configuration is such that light from the exposure lamp or outside the housing is guided to the cold cathode discharge tube via the optical fiber, the cold cathode discharge tube can be reliably irradiated with optimal light.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is an internal configuration diagram of an upper unit, and FIG. 3 is a time chart showing the operation at the start of copying of the embodiment of the present invention. FIG. 4 is a perspective view showing another embodiment of the present invention, and FIG. 5 is a left side view of FIG. 4. 4... Exposure lamp 5...Reflector 6... Optical fiber 15... Photosensitive drum 23... Developing device 33... Static elimination lamp Fig. 1 Fig. 3

Claims (3)

[Claims] (1) An image forming means that forms an image on a transfer target based on an electrostatic latent image formed on the surface of a photoreceptor, and an image forming means that emits light onto the surface of the photoreceptor after image formation has been completed. An image forming apparatus comprising: a cold cathode discharge tube that irradiates light to erase charges on the photoreceptor; and light irradiation means that irradiates the cold cathode discharge tube with light. (2) An image forming means that forms an image on a transfer target based on an electrostatic latent image formed on the surface of the photoreceptor, and an image forming means that emits light onto the surface of the photoreceptor after the image formation has been completed. An image characterized by comprising: a cold cathode discharge tube that irradiates the photoreceptor to erase the electric charge accumulated on the photoreceptor; and an optical fiber that guides light from an exposure lamp that exposes the document to the cold cathode discharge tube. Forming device. (3) An image forming means for forming an image on a transfer target based on the electrostatic latent image formed on the surface of the photoreceptor, and an image forming means for directing light onto the surface of the photoreceptor after image formation by the image forming means has been completed. An image forming apparatus comprising: a cold cathode discharge tube that irradiates the photoreceptor to erase electric charges on the photoreceptor; and an optical fiber that guides light from outside the housing to the cold cathode discharge tube.