JPH0736158U - Electrophotographic recording device - Google Patents

Abstract

(57) [Abstract] [Purpose] Fluorescence at the start of copying is provided by a structure that facilitates filter damage prevention, dust adhesion prevention, fluorescent lamp replacement and filter cleaning in the pre-transfer static eliminator of the electrophotographic recording device. By eliminating the fluctuation of the light quantity of the lamp, the copy yield is greatly improved even during high-speed copying. [Structure] A fluorescent lamp is attached to the base of a casing made up of a base and a lid body which is detachably covered and fixed to the base through a socket, and the wavelength band in which the fluorescent lamp causes light fatigue to the photoconductor is cut. A pre-transfer static eliminator by attaching a resin filter to the pre-transfer static eliminator to cover the window opened in the cover so as to be interposed between the fluorescent lamp and the photoconductor. Is set at a fixed position with respect to the photoconductor, and an electrophotographic recording apparatus further provided with a heater for setting a predetermined temperature in the vicinity of a fluorescent lamp in the casing in addition to the electrophotographic recording apparatus.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electrophotographic recording apparatus having an improved pre-transfer charge erasing exposure device.

[0002]

[Prior art]

 Fluorescent lamps have been conventionally used in the pre-transfer charge-eliminating exposure device in order to obtain a large amount of light that can be applied to small-sized toner particles and high-speed transfer.

However, a fluorescent lamp has a wide emission spectrum range, and particularly includes a wavelength band of 650 to 750 nm that causes fatigue of a photoreceptor as shown in the graph of FIG.

Therefore, a glass filter having a characteristic of sufficiently cutting such a wavelength band is used.

The technique of using a glass filter for such a residual potential has been conventionally introduced in JP-A-63-29771.

[0006]

[Problems to be solved by the device]

 However, such glass filters often break and break during use and maintenance, and replacement work is troublesome, and there are problems in productivity and handleability.

Furthermore, when a fluorescent lamp is used, in a low temperature state until the fluorescent lamp is warmed up, a required amount of light cannot be obtained, and sufficient pre-transfer charge erasing exposure cannot be performed. Therefore, the copy just after the start of the copy caused poor transfer, and the yield was not good. This was especially noticeable in high-speed recording.

In Japanese Patent Laid-Open No. 3-72385, a thermistor is attached to the glass tube wall of the fluorescent lamp for heater control, but the fluorescent lamp replacement work is troublesome, and the thermistor is discarded. There was a lot of waste, and the maintenance work efficiency was very poor.

The present invention solves these problems and provides a filter that does not cause light fatigue to the photoconductor, has good maintainability, and is resistant to dirt and is not damaged, and also provides a steady state of the light intensity of the fluorescent lamp. It is an object of the present invention to provide an electrophotographic recording apparatus having a high copy yield, which can obtain high-speed electrophotographic recording stably and operate efficiently at high speed.

[0010]

[Means for Solving the Problems]

 This object is achieved by any one of the following technical means a, b, c and d.

(A) A fluorescent lamp is attached to the base of a casing made up of a base and a lid that is detachably mounted on and fixed to the base through a socket, and the wavelength at which the fluorescent light causes light fatigue on the photoconductor. A resin filter for cutting the belt is interposed between the fluorescent lamp and the photosensitive member and is attached to the lid body so as to cover the window opened in the lid body to form a pre-transfer static eliminator, An electrophotographic recording apparatus characterized in that a charge eliminating exposure device is set at a fixed position with respect to the photoconductor.

(B) The electrophotographic recording apparatus according to item (a), wherein the resin filter is coated with a conductive thin film or the resin material is a conductive resin.

(C) A positive thermistor and a resistance sheet directly connected thereto are attached to the inner wall surface of the casing along the light emitting tube of the fluorescent lamp in addition to the item a or b, and the predetermined temperature of the inner wall surface is detected. Then, the electrophotographic recording apparatus is characterized in that it is operated so as to be turned on below the temperature and turned off above the temperature, and the resistance sheet is provided as a heater.

(D) In addition to item a or b, a radial heater is provided along the light emitting tube of the fluorescent lamp on the inner wall of the casing to repeatedly balance heat absorption and heat dissipation in the temperature range of 30 to 45 ° C. An electrophotographic recording device characterized by being attached.

[0015]

【Example】

 An embodiment of the present invention will be described together with its action with reference to the drawings.

FIG. 1 is a side view of a process cartridge 10 in the electrophotographic recording apparatus of the present invention. The process cartridge 10 is provided with a photosensitive drum 12 between two frames 11 on both sides, and a pre-charging charge erasing exposure device 13, a charging device 14, an image exposure light entrance port 15, and a magnet on the outer peripheral portion thereof. A developing device 20 including a body 22 and a developing sleeve 21 concentric with the body 22, a pre-transfer charge eliminating exposure device 30, a transfer separator 40, a toner concentration controller 50, and a cleaner are provided. However, the cleaner is omitted in FIG. 1, and the transfer separator 40 may not be included in the cartridge 10 and may be attached to the electrophotographic recording apparatus.

Since the photoconductor 12 is subject to light fatigue due to the wavelength band to be projected, the pre-charging static eliminator 13 has a small amount of light, and the amount of light of a light emitting diode (LED) is sufficient for static erasing. It is possible to easily avoid light fatigue by selecting an LED that does not include the light fatigue wavelength band, and the light received by the photoconductor 12 at the image exposure light entrance port 15 is also an image exposure optical system lens (projection lens). Light fatigue is avoided because the light fatigue wavelength band is cut by the coating provided in ().

However, the pre-transfer charge erasing exposure device 30 arranged next to the developing device 20 requires a large amount of light exposure to perform exposure from above the toner image developed on the photoconductor 12, and therefore the light emitting diode is used. However, the commercially available large-capacity fluorescent lamp is used, and the photoconductor 12 is exhausted as it is. Therefore, a filter for cutting the above wavelength band is included. Conventionally, glass has been used for this filter, and it was easy to break and it took time to replace it. Therefore, in the embodiment of the present invention, the filter 38 for cutting the light in the wavelength band of 650 to 750 nm, which is made of resin, is used as shown in the transparency curve of FIG. This filter 38 can sufficiently avoid light fatigue of the photoconductor 12. However, resin filters are liable to be charged with static electricity and dust such as toner is liable to be attached. If it is too dirty, the light intensity of the sufficient charge-eliminating pre-transfer exposure may be insufficient, which may cause problems in transfer separation. Therefore, it is necessary to carry out regular cleaning. The above is the embodiment of claim 1. In order to avoid this, in the second embodiment, both the filter 38 coated with a conductive thin film and the resin itself made of a conductive resin were used. As a result, both of them became less prone to dust such as toner, and the cleaning interval was greatly extended, making handling easier. The above is the embodiment of claim 2. Here, the structure of the pre-transfer charge erasing exposure device 30 used in the present invention will be described with reference to the front view of FIG. 2, the top view of FIG. 3 and the XX sectional view of FIG.

The pre-transfer static eliminator 30 has a casing 30A composed of a base body 31 and a lid 33 covering the base body 31, and metal fittings 32 integrally attached with sockets 34A are provided at both ends of the base body 31 with screws 32A. Mounted and fixed by. The fluorescent lamp 34 is fitted and set through the socket 34A. A filter 38 is attached to the lid 33 with a screw 38A so as to close the window 33A.

A heater 37 is attached and fixed to the inner wall surface of the lid 33 that is perpendicular to the window 33A, as described later. The lid 33 is attached to the base 31 at two positions with screws 36 and is housed in the casing 30A to form the pre-transfer static eliminator 30. Then, the exposure unit 30 is fastened and fixed to the mounting seat of the frame 11 of the process cartridge 10 by the screw 35 through the mounting hole provided in the base 31 of the exposure unit 30. An embodiment of the heater 37 will be described together with its operation. In this heater, the casing 30A is designed so that the heater 37 is automatically operated so that heat absorption and heat radiation are repeated at the boundary of a temperature of about 40 ° C. as a boundary. In addition, fluorescent lamps have the characteristic that the amount of emitted light is not stable below such a temperature (about 40 ° C), and in such a state, static elimination before transfer is extremely unstable. However, by using the above-mentioned heater 37, the light quantity is always stable. As a result, when the power switch of the electrophotographic recording apparatus is turned on and the copy operation is possible, the copy button can be pressed and the copy in the normal state can be started immediately. Therefore, even for high-speed recording, the light intensity of the fluorescent lamp is stable until the copy button is pressed, so that normal copying can always be stably achieved from the beginning. This is the embodiment of claim 4. For this purpose, if the positive thermistor and the heater 37 are connected to each other and attached to the inner wall of the lid 33 of the casing 30A, the heater is turned on and off at around 40 ° C. around the fluorescent lamp 34. Therefore, the quantity of light of the fluorescent lamp becomes constant, and the same purpose as that of the heater according to the fourth embodiment can be achieved. This is the embodiment of claim 3.

[0021]

[Effect of device]

 According to the present invention, a fatigue exposure light cut filter that is not damaged is attached to the pre-transfer static eliminator, and the fluorescent lamp can be easily replaced, and the static eliminator can be easily assembled. It became so. The cleaning of the exposure filter can be easily done by removing the lid, and the cleaning interval can be greatly extended by applying a conductive coat to the filter.

Further, by attaching a special heater to the charge eliminating exposure device, the charge eliminating exposure light amount of the fluorescent lamp is always kept in a stable region, and it becomes possible to secure a good quality copy, and even in high speed copying. It has become possible to significantly improve the yield of.

[Brief description of drawings]

FIG. 1 is a front view of a process cartridge of an electrophotographic recording apparatus of the present invention.

FIG. 2 is a front view of a pre-transfer static eliminator.

FIG. 3 is a top view of a pre-transfer static eliminator.

FIG. 4 is a sectional view taken along line XX in FIG.

FIG. 5 is a transmittance curve for each wavelength of the cut filter used in the present invention.

FIG. 6 is a curve showing a fatigue region of a photoreceptor due to each wavelength of light.

[Explanation of symbols]

 10 Process Cartridge 12 Photoreceptor 20 Developing Device 30 Pre-transfer Charge Eliminating Exposure Device 30A Casing 31 Base 33 Cover 33A Window 34 Fluorescent Lamp 35, 36 Screw 37 Heater 38 Filter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G03G 21/20 H01J 61/44 L

Claims (4)

[Scope of utility model registration request] 1. A wavelength band in which a fluorescent lamp is attached via a socket to a base of a casing composed of a base and a lid which is detachably covered with the base, and the fluorescent lamp causes light fatigue to a photoconductor. A resin filter for cutting is attached to the lid body so as to cover the window opened in the lid body by interposing it between the fluorescent lamp and the photoconductor, and a pre-transfer charge erasing exposure device is configured. An electrophotographic recording apparatus, wherein a container is set at a fixed position with respect to the photoconductor. 2. The electrophotographic recording apparatus according to claim 1, wherein the resin filter is coated with a conductive thin film or the resin material is a conductive resin. 3. In addition to claim 1 or claim 2, a positive thermistor and a resistance sheet directly connected to the positive thermistor are attached to an inner wall surface of the casing along a light emitting tube of the fluorescent lamp, and a predetermined temperature of the inner wall surface is maintained. Detected and O below the temperature
An electrophotographic recording apparatus characterized in that the resistance sheet is operated so as to be turned off by N or more, and the resistance sheet is provided as a heater. 4. In addition to claim 1 or 2, 30 to 30 on the inner wall of the casing along the light emitting tube of the fluorescent lamp.
An electrophotographic recording device equipped with a lycal heater that balances heat absorption and heat dissipation in the temperature range of 45 ° C.