JPS626276A - Exposing device - Google Patents

Abstract

PURPOSE:To obtain a sufficient quantity of light on the warming-up operation of a fixing roller and to prolong the life of a fluorescent lamp by turning off the fluorescent lamp when the quantity of light of the fluorescent lamp or light quantity equivalent value reaches a reference value set according to the temperature of the fixing roller during the warming-up operation. CONSTITUTION:The output of a light quantity detection sensor 31 and the output of a temperature detection sensor 32 are applied to a fluorescent lamp turn-on control circuit 33. The fluorescent lamp turn-on control circuit 3 stops feeding electricity to the fluorescent lamp 20 on knowing that the output of the light quantity detection sensor 31 exceeding a reference value L1 regarding the output of the temperature detection sensor 32. Simultaneously, a fixation heater generates heat and when a state wherein fixation is possible is entered, a ready lamp illuminates to indicate that copying operation is possible. When a copy button is pressed, the fluorescent lamp turn-on control circuit 33 begins to power on the fluorescent lamp 20 again to perform the copying operation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an exposure apparatus that efficiently controls the lighting of fluorescent lamps used in electronic copying machines and the like.

(Prior Art) An electronic copying machine exposes a charged drum to light in accordance with document information, and then removes a static image formed on the drum surface.
A device that forms a visible toner image on an image and transfers the visible toner image to copy paper.

FIG. 2 is a diagram showing an example of the conventional configuration of such an electronic copying machine. When the operator presses a copy start button (not shown), the device shown in the figure begins a copying operation. The photosensitive drum 1, which is rotating in the direction of the arrow, is cleaned by a blade in the cleaning section 2, after which the remaining toner on the photosensitive drum is scraped off by a blade, and then corona discharge is applied to the photosensitive drum 1 by the charged electrode 3, so that ten poles of electric charge are applied to the entire surface of the photosensitive drum 1. Becomes electrically charged. An unnecessary portion of the charge charged by the charging electrode 3 is erased by a charge eraser 4.

On the other hand, light is irradiated from an exposure unit 6, which is controlled on and off by a fluorescent lamp lighting circuit 5, to a document 8 placed on a document table 7, and the reflected light is reflected by a Selfoc lens (Japanese), which is an example of a light transmitting body. The light is focused by a lens (manufactured by Sheet Glass Co., Ltd.) 9 and irradiated onto the photosensitive drum 1.

Here, when the document table 7 is horizontally moved in the direction of the arrow in the figure,
Image information on the original 8 is focused by a SELFOC lens 9 and sequentially irradiated onto the photosensitive drum 1.

As a result, the unnecessary portion (area corresponding to the non-image portion) is charged and erased by the charge erasing unit 4, and an electrostatic latent image of the document image information is sequentially formed on the charged region of the photosensitive drum surface where an image is to be formed. Ru. The electrostatic latent image formed on the surface of the photosensitive drum 1 is converted into a visible image by adsorption of toner in the subsequent developing section 10. The toner image on the surface of the photosensitive drum is transferred to a copy paper in a transfer section 11, and the copy paper that is in close contact with the photosensitive drum 1 is separated. The separated copy paper is sent to the fixing roller 13 via the conveyance mechanism 12, and the copy paper is heated and pressurized by the fixing roller 13 to fuse the toner on the copy paper to the copy paper, and the copying operation is completed. finish.

Incidentally, as the light source 20 used in the exposure section 6, a fluorescent lamp as shown in FIG. 3 may be used. Third
In the figures, (a) is a perspective view, and (b) is a sectional view taken along the line AA'. In the figure, 21 is a bottle, 22 is a cap, 2
3 is a heater formed surrounding the fluorescent tube 24; 25 is a heat generating portion of the heater 23; The heat generating part 25 is, for example, (
As shown in (b), it is pasted around the fluorescent tube 24, and may be further fixed with a heat shrink tube (not shown) from above. Alternatively, there are cases where the tube is simply attached to the surface of the fluorescent tube without using a heat shrink tube. 26.2
7 is an electrode for applying a current to the heater 23, 28 is a reflective/fluorescent film, and 29 is an aperture.

The heater 23 is provided to quickly raise the temperature of the tube wall of the fluorescent tube 24.

The relationship between the tube wall temperature and the amount of emitted light of a fluorescent lamp constructed in this manner is shown in FIG. 4. In the figure, the horizontal axis shows the fluorescent lamp tube wall temperature, and the vertical axis shows the amount of emitted light. The tube wall temperature of the fluorescent lamp reaches a predetermined reference value (T in the figure) within the warm-up time of the fixing heater provided in the fixing row 513.
If o) is not reached, the amount of light will be insufficient. The amount of light emitted at the temperature TO is Lo, and if the tube wall temperature of the fluorescent lamp does not exceed To within the warm-up time, the amount of light will fall below Lo, resulting in an insufficient amount of light, making it impossible to copy an accurate image.

(Problem to be Solved by the Invention) In order to compensate for the lack of the tip of the fluorescent lamp described above, conventionally, when the fixing roller is warmed up, the fluorescent lamp is always turned on to hasten the rise in tube wall temperature, and the fixing roller is warmed up. In some cases, the temperature of the tube wall was set to be equal to or higher than the reference value To by the time the process was completed.

However, in such a conventional method, the fluorescent lamp is always turned on while the fixing roller is warmed up, which shortens the life of the fluorescent lamp.

Therefore, in order to extend the life of the fluorescent lamp, it is conceivable to turn off the lighting of the fluorescent lamp when the amount of light from the fluorescent lamp reaches a reference value Lo shown in FIG. 4 during warm-up.

Incidentally, the relationship between the warm-up time, the tube wall temperature of the fluorescent lamp, and the temperature of the tube wall heater is as shown in FIG. In the figure, the horizontal axis shows the warm-up time, the vertical axis shows the temperature, the solid line A shows the temperature of the tube wall heater, and the broken tDB and one-dot chain line C show the tube wall temperature.

As is clear from the broken line B in FIG. When the ambient temperature and tube wall temperature TS are low, the tube wall temperature starts to decrease from the moment the fluorescent lamp is turned off, as shown in B, and reaches 1 when the fixing roller warms up.
．． Time 1z when the temperature of the tube wall heater reaches the reference value To from
During this period, the temperature of the tube wall of the fluorescent lamp that is turned on is low and the amount of light is insufficient, and if copying is started during this time, proper exposure will not be performed.

The present invention has been made in view of these points, and
The purpose is to realize an exposure device that can obtain a sufficient amount of light when the fixing roller is warmed up, and can further extend the life of the fluorescent lamp.

(Means for Solving the Problems) The present invention, which solves the problems described above, illuminates the document surface with a fluorescent lamp, and irradiates the photoreceptor with the reflected light or light based on the reflected light to eliminate static electricity. A latent image is formed, and the static 1! An exposure device used in an image forming apparatus that develops a latent image, attaches toner to copy paper, and fixes it as an image through a fixing roller, and is a light amount and light amount equivalent value detection device that detects the light amount or light amount equivalent value of a fluorescent lamp. a sensor, a temperature detection sensor that detects the temperature of the fixing roller, and a fluorescent lamp lighting control circuit that controls lighting of the fluorescent lamp based on the output of the light a, the light amount equivalent value detection sensor, and the temperature detection sensor, The present invention is characterized in that the lighting of the fluorescent lamp is turned off when the light amount or light amount equivalent value of the fluorescent lamp reaches a reference value set according to the temperature of the fixing roller during warm-up.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of the present invention, and is the same as FIG. 2, with the same numbers used for minus.

In the figure, 31 is a light m detection sensor that is an example of a light amount/light amount equivalent value detection sensor that detects the amount of light emitted from the fluorescent lamp 20;
32 is a temperature detection sensor that detects the temperature of the fixing roller 13; 33 is the light amount detection sensor 31 and the temperature detection sensor 32;
This is a fluorescent lamp lighting control circuit that performs on/off control of energization to the fluorescent lamp 20 in response to the output of the fluorescent lamp 20 . The fluorescent lamp lighting control circuit 3
3, the output of the light amount detection sensor 31 is 1m detection sensor 32
The reference value Ll (Ll>Lo
), the power supply to the fluorescent lamp 20 is turned off. The operation of the device configured as described above will be explained as follows.

When you turn on the electronic copying machine, first the fixing roller 13
The fixing heater (not shown), the fluorescent lamp 20, and the fluorescent lamp heater 23 (see FIG. 3) are energized. As a result, the tube wall of the fluorescent lamp generates self-heating due to energization and the heater 2
Due to the heat generated from the heat generating part 25 by energizing 3,
gradually rises. As the temperature of the tube wall increases, the amount of light emitted from the fluorescent tube through the aperture section 29 also increases accordingly, as shown in FIG. Here, the output of the light amount detection sensor 31 and the output of the temperature detection sensor 32 are added to the fluorescent lamp lighting control circuit 33. And fil
? ! When the light lamp lighting JII111 circuit 33 learns that the output of the light amount detection sensor 31 exceeds the reference value Ll related to the output of the temperature detection sensor 32, it stops energizing the fluorescent lamp 20.

Meanwhile, during this time, the fixing heater also generates heat and becomes ready for fixing. When fixing is possible, the electronic copying machine's READY lamp lights up to notify the operator that copying is possible.

When the operator presses the copy button, the fluorescent lamp lighting control circuit 3
Step 3 starts energizing the fluorescent lamp 20 again and performs the copying operation in the manner described with reference to FIG. 2 (during the copying operation, the amount of light emitted from the fluorescent lamp 20 is controlled to be constant).
. Once the power supply to the fluorescent lamp 20 is stopped, the temperature of the wall of the fluorescent lamp tube hardly decreases and is maintained at or above To, partly because the external heater 23 is constantly energized. - Therefore, when the operator presses the copy button and energization of the fluorescent lamp 20 starts, the amount of emitted light quickly reaches the reference value Lo, providing a sufficient amount of light.

As described above, according to the present invention, the temperature of the fixing roller is detected when the fixing roller warms up, and the lighting of the fluorescent lamp is turned off at the reference value L1 related to the detected temperature. Even when the ambient concentration and tube wall temperature TS of the fluorescent lamp are low, the tube wall temperature of the fluorescent lamp becomes as shown by 1 mc in Figure 5, and proper exposure is achieved even at 7:00 t1 after warm-up. A sufficient amount of light can be obtained. or,
If the ambient concentration and tube wall temperature TS of the fluorescent lamp at the time of power-on are high (close to Tl in Figure 4), it is possible to shorten the lighting time of the fluorescent lamp, extending the life of the light lamp. At the same time, power consumption can be kept low.

In the above explanation, the case where the light intensity of the fluorescent lamp exceeds the reference value L1 after the power is turned on is explained by stopping the power supply to the fluorescent lamp and leaving it as it is, but the present invention is not limited to this. For example, once the power to the fluorescent lamp is stopped, once the tube wall temperature drops to a certain value, the fuser roller is brought into a ready state by performing on-off control that restarts the power to the fluorescent lamp. You may also have Such a method is particularly effective when the electronic copier is located in a room that is not temperature controlled (especially during the winter).

Further, in the above explanation, the case where the power supply to the fluorescent lamp is stopped when the light amount of the fluorescent lamp reaches the reference value was explained as an example, but the present invention is not limited to this, and the tube wall temperature is set to the reference value. Set a predetermined value corresponding to the amount of light, and use this constant value (
For example, the same effect can be obtained by stopping the energization when T1) is reached.

Alternatively, the power supply to the fluorescent light may be stopped when the time during which the fluorescent light is energized exceeds the time corresponding to the reference light amount value [1]. Although the above embodiment has been described with respect to a conventional copying machine, it is of course applicable to a copying machine using a laser optical system.

(Effects of the Invention) As described above in detail, according to the present invention, a sufficient amount of light can be obtained when the fixing roller is warmed up, and the life of the fluorescent lamp can be significantly extended.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing an example of the conventional structure of an electronic copying machine, Fig. 3 is a diagram showing an example of the structure of a fluorescent lamp, and Fig. 4 is a diagram showing an example of the structure of a fluorescent lamp. FIG. 5, which is a diagram showing the characteristics of the amount of emitted light, is a diagram showing examples of temperature changes in various parts during warm-up. 1... Photosensitive drum 2... Cleaning section 3.
... Charged electrode 4 ... Charge erasing section 5 ... Fluorescent lamp lighting circuit 6 ... Exposure section 7 ... Original table
8... Original 9... SELFOC lens 10... Developing section 11... Transfer section 12...
Conveyance mechanism 13...Fixing roller 20...Fluorescent lamp 31...Light amount detection sensor 32...Temperature detection sensor 33...Fluorescent lamp lighting control circuit Patent applicant Roku Konishi Photo Industry Co., Ltd. Agent Patent attorney Photosensitive drum 10; Developing section 2; Cleaning section 11; Transfer section 3: m 12: g 7; Original table 31; Light amount detection sensor 8; Original 32; Density detection sensor 9 ; SELFOC lens Fig. 4 Fluorescent lamp tube wall temperature etc. Fig. 5

Claims (1)

[Claims] Irradiating the document surface with a fluorescent lamp and irradiating the photoreceptor with reflected light or light based on the reflected light to form an electrostatic latent image,
An exposure device used in an image forming apparatus that develops the electrostatic latent image, attaches toner to copy paper, and fixes it as an image through a fixing roller, and is a light amount or light amount equivalent that detects the light amount or light amount equivalent value of a fluorescent lamp. A value detection sensor, a temperature detection sensor that detects the temperature of the fixing roller, and a fluorescent lamp lighting control circuit that controls lighting of the fluorescent lamp based on the output of the light amount, light amount equivalent value detection sensor, and temperature detection sensor. An exposure apparatus characterized in that the lighting of the fluorescent lamp is turned off when the light amount or light amount equivalent value of the fluorescent lamp reaches a reference value set according to the temperature of the fixing roller during warm-up.