JPH08110671A - Color image forming device - Google Patents

Abstract

PURPOSE: To prevent an optical system, an exposing lamp, etc., from being soiled and the leakage and reflection of light from occurring by providing a protective cover on either one of an image exposing means, a uniformly exposing means or a photodetector means. CONSTITUTION: At the time of inserting a photoreceptor drum 10, the right end part of a flange 10b pushes a roller 154 provided on an opening/closing lever 153 to push down the lever 153 restrained by a stopper 156 clockwise against the energizing force of a spring 155 with a supporting shaft 152 provided in a fixed plate 151 fixed on a holding member 20 as the center. The tapered part of an opening/closing pin 157 provided on one end of the lever 153 pushes up the bent part 164 of the protective cover 163 against the force of the spring by the turning of the lever 157 to open both protective covers 163 and to enable the exposure of an exposure optical system 12Y being the image exposing means or a pre-electrification exposure device, a simultaneous transfer exposure device, a photosensor, etc., being an exposing means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device in which a plurality of charging means, image exposing means and developing means are arranged on the peripheral surface of an image forming body to superpose toner images during one rotation of the image forming body. The present invention relates to a photographic color image forming apparatus.

[0002]

2. Description of the Related Art As a method for forming a multicolor image, a monochromatic toner image formed on each of the photoconductors is transferred by using a photoconductor, a charging device, a developing device and the like as many images as necessary. A color image forming apparatus for forming a color image by superimposing the same on one or the like, or charging one color for each color by rotating one photoconductor a plurality of times.
A color image forming apparatus that forms a color image by repeating image exposure and development, or a color image formation that forms a color image by sequentially performing charging, image exposure and development for each color within one rotation of one photoconductor. Devices and the like are known.

However, in each of the above-mentioned image forming apparatuses, an image is provided with the same number of photoconductors, charging devices, and developing devices as the required colors, and the monochromatic toner image formed on each photoconductor is superposed on the transfer body or the like. A color image forming apparatus for forming a color image has a drawback that the volume of the apparatus becomes large because it requires conveyance of a plurality of photoconductors or transfer bodies. On the other hand, one photoconductor is rotated a plurality of times to charge for each color, A color image forming apparatus that repeats image exposure and development to form a color image has only one charging unit, image exposing unit, and photoconductor, so that the volume is reduced, but the size of the image formed is smaller than that of the photoconductor. There is a restriction that it is limited to the surface area or less.

Further, although a color image forming apparatus that forms a color image by sequentially performing charging, image exposure and development for each color within one rotation of one photoconductor enables high speed image formation, Since it is necessary to dispose a plurality of sets of a charging device, an image exposing unit and a developing device within one round, there is a risk that the image leaks from the toner leaking from the developing device in the vicinity of the optical system for performing the image exposure and the image quality is impaired. Since it is necessary to increase the distance between the image exposure means and the developing device in order to avoid it, there is a contradiction that the diameter of the photoconductor is inevitably increased and the device is enlarged. For the purpose of avoiding this drawback, the substrate of the image forming body is formed of a transparent material, and a plurality of image exposing means are housed therein, and the image is exposed through the substrate to the photosensitive layer formed on the outer periphery thereof. An apparatus of the form is proposed, for example, by Japanese Patent Laid-Open No. 5-307307.

[0005]

As is well known, the image forming body is driven and rotated during image formation, and it is usually replaced from the main body of the apparatus because it is replaced for a certain period of time and is subject to maintenance or the like. It has a structure that can be removed independently.

On the other hand, the image exposure means is always kept stationary, the period of use is remarkably longer than that of the image forming body, and there are also structural reasons that it is installed inside the image forming body. In many cases, it is directly fixed to the main body of the device.

Therefore, when the image forming body is attached to or detached from the main body of the apparatus, the optical system is contaminated with toner or the like, or the uniform exposure lamp or the photo sensor as the light detecting means is contaminated. Further, in such an optical system-containing image forming apparatus, there is a problem that a latent image of a photoreceptor, which is an image forming body, is not properly formed due to light leakage or light reflection.

The present invention solves this problem and improves the result.
When the image forming body is attached to or detached from the apparatus body, the optical system provided inside the image forming body is not contaminated by toner or the like, and the exposure lamp or the photo sensor is not contaminated.
Another object of the present invention is to provide a color image forming apparatus capable of high-quality image recording without causing light leakage or light reflection due to an image exposure device or the like.

[0009]

SUMMARY OF THE INVENTION The above object is to provide a plurality of sets of charging means, an image exposing means and a developing means included in the image forming body, around the image forming body. On the other hand, color image formation in which toner images are superposedly formed on the image forming body by repeating charging by the charging means, image exposure by the image exposing means and development by the developing means, and then collectively transferring to a transfer material. In the apparatus, a protective cover that can be opened and closed is provided in at least one of the image exposure unit, the uniform exposure unit that exposes the image forming body, or the light detection unit. (First invention). Further, the color image forming apparatus is characterized in that the protective cover is opened / closed in association with the attachment / detachment operation of the image forming body, and the image exposure unit, the uniform exposure unit, or the light detection unit is held. A color image forming apparatus having a holding member provided with the protective cover is a preferred embodiment.

Further, a plurality of sets of charging means, an image exposing means and a developing means included in the image forming body are arranged around the image forming body, and the image forming body is charged by the charging means. In a color image forming apparatus that repeats image exposure by the image exposure unit and development by the developing unit to form toner images on the image forming body and then collectively transfers the toner images onto a transfer material, an antireflection unit is provided. A color image provided on at least one of the edge portion of the image forming body, the image exposing means, the uniform exposing means for exposing the image forming body, or the holding member holding the light detecting means. This is achieved by the forming device (second invention). The anti-reflection means is a black paint, a color image forming apparatus, the image exposure means, the uniform exposure means, and / or the light detection means. A color image forming apparatus characterized in that a light-shielding member is provided in parallel to the exposure light in the body direction, and a color image characterized in that the light-shielding member is coated to prevent reflection. The forming device is the preferred embodiment.

Further, a plurality of sets of charging means, an image exposing means and a developing means included in the image forming body are arranged around the image forming body, and the image forming body is charged by the charging means. In the color image forming apparatus, the toner image is superposed on the image forming body by repeating the image exposure by the image exposing means and the developing by the developing means, and then the toner images are collectively transferred to a transfer material. Opposing at least one of the image exposing means included in the image forming body, the uniform exposing means for exposing the image forming body, or the light detecting means outside, to the exposure light toward the image forming body. Then, the present invention is achieved by a color image forming apparatus (third invention) characterized in that an antireflection member is provided. A color image forming apparatus is characterized in that the antireflection member is painted black.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of each embodiment of the present invention, the structure of a color image forming apparatus common to each invention will be described with reference to FIGS. FIG. 1 is a sectional configuration diagram of a color image forming apparatus of the present invention, and FIG. 2 is a main part diagram of the color image forming apparatus of FIG.

Reference numeral 10 denotes a photosensitive drum, which is a drum-shaped image forming body, and has a transparent conductive layer, an a-Si layer or an organic photosensitive layer on the outer periphery of a cylindrical substrate formed of a transparent member such as optical glass or transparent acrylic resin. A photoreceptor layer such as a layer (OPC) is formed. 11Y, 11M, 11C and 11K
Is a charging unit used in the image forming process of each color of yellow (Y), magenta (M), cyan (C), and black (K), for example, a scorotron charger, pre-exposure as a uniform exposure unit. The photoconductor drum 10 uniformly exposed by the device 123 performs a charging action on the above-mentioned organic photoconductor layer by the grid held at a predetermined potential and the corona discharge by the discharge wire, and the photoconductor drum 10 is charged. It gives a uniform potential.

12Y, 12M, 12C and 12K are FL (phosphor emission), EL (electroluminescence) and PL (plasma discharge) in which light emitting elements arranged in the axial direction of the photosensitive drum 10 are arranged in a line. , LED (light-emitting diode) and elements with optical shutter function are arranged in a line L
Exposure elements 121Y, 121M, 121C and 121K such as ISA (magneto-optical effect optical shutter array), PLZT (transmissive piezoelectric element shutter array), LCS (liquid crystal shutter),
SELFOC lenses 122Y and 122 serving as equal-magnification imaging elements
In the exposure optical system which is an image exposure device configured as a unit with M, 122C and 122K, the image signals of the respective colors read by the separate image reading device are sequentially taken out from the memory, and the exposure optical system 12Y, 12M, 12C and 12K are respectively inputted as electric signals. The exposure optical systems 12Y, 12M, 12C and 12K are all mounted on a cylindrical holding member 20 and housed inside the base of the photosensitive drum 10.

13Y, 13M, 13C and 13K are developing means using a non-contact developing method for accommodating yellow (Y), magenta (M), cyan (C) and black (K) developers, for example. , Developing device, photoconductor drum
Developing sleeves 130Y, 130M, 130C and 130K that rotate in the same direction by abutting rollers 140Y, 140M, 140C and 140K against the peripheral surface of 10 and developing sleeves 130Y, 130M, 130C and 130K Supply rollers 131Y, 131M, 131C and 131K for supplying the agent, and stirring rollers 132Y, 132M, 132C and 132K, 133
It is equipped with Y, 133M, 133C and 133K. Developing sleeves 130Y, 130M, 130C and 130K and developing units 13Y and 13
The developer in M, 13C, and 13K is kept in non-contact with the photoconductor drum 10, but the gap between the photoconductor drum 10 and the developing sleeves 130Y, 130M, 130C, and 130K is non-contact with the drum end. Abutting rollers 140Y, 140M, 140C that press the photoconductor drum 10 at the image portion and rotate following the photoconductor drum 10
And 140K.

The developing devices 13Y, 13M, 13C and 13K
Is the charging and exposure optical system 12Y, 12M, 12C by the scorotron chargers 11Y, 11M, 11C and 11K described above.
The electrostatic latent image formed on the photosensitive drum 10 by image exposure with 12K is reversely developed in a non-contact state by applying a developing bias voltage.

The image of the original is read by an image reading apparatus separate from the present apparatus, and the image read by the image pickup device or the image edited by the computer is once used as an image signal for each color of Y, M, C and K. Stored and stored in memory.

By the start of image recording, the photoconductor driving motor is started to rotate the photoconductor drum 10 clockwise.
At the same time, application of electric potential to the photoconductor drum 10 is started by the charging action of the scorotron charger 11Y.

After the photosensitive drum 10 is applied with an electric potential,
In the exposure optical system 12Y, the exposure by the electric signal corresponding to the first color signal, that is, the yellow (Y) image signal is started, and the yellow (Y) image of the original image is formed on the photosensitive layer on the surface by the rotational scanning of the drum. To form an electrostatic latent image corresponding to.

The latent image is reversely developed by the developing device 13Y in a state where the developer on the developing sleeve is not in contact with the latent image, and a yellow (Y) toner image is formed according to the rotation of the photosensitive drum 10.

Then, the photosensitive drum 10 is further provided with a scorotron charger 11M on the yellow (Y) toner image.
An electric signal is applied by the charging action of the exposure optical system 12M, an exposure is performed by an electric signal corresponding to the second color signal of the exposure optical system 12M, that is, an image signal of magenta (M), and the non-contact reversal development is performed by the developing device 13M. A magenta (M) toner image is sequentially formed on the yellow (Y) toner image.

Scorotron charger by similar process
The cyan (C) toner image corresponding to the third color signal is further converted to a fourth color signal by the scorotron charger 11K, the exposure optical system 12K, and the developing device 13K by 11C, the exposure optical system 12C, and the developing device 13C. Corresponding black (K) toner images are successively superposed and formed, and a color toner image is formed on the peripheral surface of the photosensitive drum 10 within one rotation.

These exposure optical systems 12Y, 12M, 12C and
The exposure of the photosensitive layer of the photoconductor drum 10 by 12K is performed through the above-mentioned transparent substrate from the inside of the drum. Therefore, the exposure of the image corresponding to the second, third, and fourth color signals is performed without any influence of the toner image previously formed, and is equivalent to the image corresponding to the first color signal. It is possible to form an electrostatic latent image. Exposure optical system
Photosensitive drum due to heat generated by 12Y, 12M, 12C and 12K
To stabilize the temperature in 10 and prevent the temperature from rising, a material having good thermal conductivity is used for the holding member 20, a heater is used when the temperature is low, and heat is radiated to the outside through a heat pipe when the temperature is high. By taking measures such as the above, it can be suppressed to such an extent that there is no problem. In the developing operation by the developing devices 13Y, 13M, 13C and 13K, the developing sleeves 13 are attached to the photosensitive drums 10 whose transparent conductive layers are grounded.
DC for 0Y, 130M, 130C and 130K, or
Further, a developing bias to which an alternating current is applied is applied, jumping development is performed by a one-component or two-component developer housed in the developing device, and non-contact reversal development for adhering toner to an exposed portion is performed. There is.

Thus, the color toner image formed on the peripheral surface of the photosensitive drum 10 is sent out from the paper feeding cassette 15 by the sending roller 15a in the transfer device 14a.
The toner is conveyed to the timing roller 16 by the pair of conveying rollers 15b and 15c, and is driven in synchronization with the toner image on the photosensitive drum 10 which is exposed by the transfer simultaneous exposure device 124 as the uniform exposure means by the driving of the timing roller 16. It is transferred onto a transfer paper P which is a transfer material to be paper. When the transfer material is thick paper or OHP, the transfer material is sent from the manual paper feed tray 210 to the timing roller 16 by the manual feed roller 15d and the conveying roller pair 15e.

The transfer paper P on which the toner image has been transferred is separated from the peripheral surface of the drum by being removed of the charge by the static eliminator 14b, and then the transfer belt stretched between the transfer drive roller 14c and the driven roller 14d. It is conveyed to the fixing device 17 by 14e. In the transfer section, light is removed by a transfer simultaneous exposure device 124 as a uniform exposure means to improve transfer efficiency,
Separation performance is improved. In the fixing device 17, the toner is heated and pressure-bonded between the fixing roller 17a and the pressure-bonding roller 17b to fuse and fix the toner on the transfer paper P, and then the tension roller pair
The sheet 17c is discharged from the fixing device 17 by the fixing outlet roller pair 17d, is conveyed by the sheet discharge conveyance roller pair 18a, and is discharged onto the sheet discharge tray 200 at the upper part of the apparatus via the sheet discharge roller 18.

On the other hand, the photosensitive drum 10 from which the transfer paper has been separated has the cleaning blade 19a in the cleaning device 19.
Thus, the surface of the photoconductor drum 10 is rubbed to remove and clean residual toner, and the toner image of the original image is continuously formed or is temporarily stopped to form a new toner image of the original image. The waste toner scraped off by the cleaning blade 19a is discharged to a waste toner container (not shown) by the toner transport screw 19b. Reference numeral 125 denotes a jam detection photo sensor used as a light detection unit.

The photoreceptor drum 10 has a plurality of scorotron chargers on the outer peripheral surface thereof even if the diameter of the drum is relatively small because the exposure optical system is housed therein.
11Y, 11M, 11C and 11K, developing unit 13Y, 13M, 13C
And an outer diameter of 60 can be installed.
The device volume can be made compact by using a drum with a small diameter of mm to 150 mm.

The first embodiment of the first invention of the present invention will be described with reference to FIGS. The first embodiment is a pre-charging exposure apparatus or a simultaneous transfer exposure apparatus as an exposure optical system which is an image exposure means, and other uniform exposure means which is an exposure means according to insertion and removal of a photosensitive drum. In order to protect the exposed portion by opening and closing a protective cover provided in the opening of the exposed portion such as a photo sensor as a light detecting means, FIG. 3 is a diagram showing a state when the photosensitive drum is pulled out. 4 is
FIG. 6 is a diagram showing a state in which the photosensitive drum is attached, and FIG. 5 is a diagram showing an opened / closed state of the protective cover.
FIG. 5A is a diagram showing an opened / closed state of the protective cover in the state of FIG. 3 and FIG. 5B is a state of FIG.

When the photoconductor drum 10 is attached or detached, a member close to the photoconductor drum 10, for example, the developing device 13Y, 13M, 13C.
And 13K, cleaning device 19, transfer device 14a, static eliminator
14b and the like are retracted from the photosensitive surface of the photosensitive drum 10 in advance and are separated from each other. Flange 10a and 10b on both ends
The photosensitive drum 10 that is integrated with the drum mounting plate 10
The photoconductor drum 10 is attached to the reference pin 10c of f.
Two left and right guide rails (not shown) fixed to the drum mounting plate 10f on the outer side of the
The guide hole 20b provided in the holding member 20 and the drum mounting plate 10 are slid on two guide members (not shown) stretched over a and 40b and inserted in the direction of the arrow in FIG.
It engages with the reference pin 10c fixed to f, and the front side plate
Reference hole 40i provided in 40a and drum mounting plate 10f
Is engaged with a reference pin 10d provided on the side plate, and further, side plates 40a and 40b of the apparatus body are engaged by engagement of a locking member (not shown).
Exposure optical systems 12Y, 12M, 12C and 12 are provided at predetermined positions in between.
K, the pre-charging exposure device 123, the simultaneous transfer exposure device 124, the holding member 20 including the photo sensor 125, etc. are mounted in a state of being included.

The photosensitive drum 10 having the flanges 10a and 10b integrated at both ends is fitted in one side with the reference hole 20b of the holding member 20 fixed to the side plate 40b of the main body by the screw 40h. The other end is rotatably supported by the reference pin 10c fixed to the drum mounting plate 10f, and the other end by the three guide rollers 20r provided on the side plate 40b of the main body with the flange 10b. At the same time as mounting the photoconductor drum 10 on the main body of the apparatus, the flange 10b of the photoconductor drum 10
10g of gear formed on the outer circumference of the drive gear of the main body of the device 40g
And the photosensitive drum 10 is driven and rotated by its power.

When the photoconductor drum 10 is pulled out, a pair of protective covers for the left and right are provided as shown in FIG. 5 (A), and the left protective cover 163 is for the photoconductor drum 10 shown in FIG. Is installed rotatably around a supporting cover 161 fixed to the holding member 20 as a supporting shaft, which is provided in a pair in the front and rear in the insertion direction of the protective cover supporting shaft 162, and is rotated by a spring 165 in a clockwise direction. In response, open / close pin 157
The bent portion 164 of the protective cover 163 comes into contact with the stopper as a stopper,
The protective cover 163 is closed and stopped. Similarly, the protective cover on the right side also remains closed.

When the photosensitive drum 10 is inserted, the flange 10
By pressing a roller 154 provided on the opening / closing lever 153, the right end of b is opened / closed by a stopper 156 about a support shaft 152 provided on a fixed plate 151 fixed to the holding member 20. The lever 153 is resisted against the negative force of the spring 155,
Push it down in a clockwise direction. When the opening / closing lever 153 is rotated, the opening / closing pin 157 provided at the other end of the opening / closing lever 153.
The tapered portion 157 a of the protective cover 163 bends the bent portion 164 of the spring 165.
Push up against the force of the
The exposure optical system 12Y, 12M, 12C and 12K, which is the image exposure means, or the exposure means, which is the pre-charging exposure device 123, the transfer simultaneous exposure device 124, the photosensor 125, etc., is opened as shown in FIG. Can be exposed. It is preferable that the protective cover is moved at the end of mounting the photosensitive drum or at the start of insertion / removal because the exposure time is short.

Next, a second embodiment of the first invention of the present invention will be described with reference to FIGS. In the second embodiment, the protective pipe, which is a protective cover provided on the outer periphery of the holding member, is rotated inside the photosensitive drum according to the insertion and removal of the photosensitive drum, and the slit provided on the protective pipe is rotated. Position is aligned with the exposure optical system that is the image exposure unit, and other exposure units such as the pre-charging exposure device that is the exposure unit, the simultaneous transfer exposure device, and the photosensor. To protect, Figure 6
FIG. 8 is a diagram showing a state in which the photosensitive drum is attached, FIG. 7 is a diagram showing a positional relationship between the exposure means and the protection pipe in the state of FIG. 6, and FIG.
It is a figure which shows the operating state of the drive lever of the protection pipe at the time of attachment / detachment. FIG. 8 (A) shows a state at the time of mounting, and FIG. 8 (B) shows
It is a figure which respectively shows the state at the time of attachment / detachment.

When the photoconductor drum 10 is attached or detached, a member close to the photoconductor drum 10, for example, the developing device 13Y, 13M, 13C.
And 13K, cleaning device 19, transfer device 14a, static eliminator
14b and the like are retracted from the photosensitive surface of the photosensitive drum 10 in advance and are separated from each other. Flange 10a and 10b on both ends
The photosensitive drum 10 that is integrated with the drum mounting plate 10
The photoconductor drum 10 is attached to the reference pin 10c of f.
Two left and right guide rails (not shown) fixed to the drum mounting plate 10f on the outer side of the
A reference hole 20 provided in the holding member 20 by being slidably inserted into two guide members (not shown) stretched over a and 40b.
b is engaged with the reference pin 10c fixed to the drum mounting plate 10f, and the reference hole 40i provided in the front plate 40a is provided.
And the reference pin 10d provided on the drum mounting plate 10f are engaged with each other, and the exposure optical system is placed at a predetermined position between the side plates 40a and 40b of the apparatus main body by the engagement of a locking member (not shown).
The holding member 20 having 12Y, 12M, 12C and 12K, the pre-charging exposure device 123, the simultaneous transfer exposure device 124, the photosensor 125, etc. is mounted in a state of being enclosed.

As shown in FIG. 6, flanges 10a are provided at both ends.
The photosensitive drum 10 in which 10 and 10b are integrated is fixed to the drum mounting plate 10f, which is fitted to one side and fitted with the reference hole 20b of the holding member 20 fixed to the side plate 40b of the main body by the screw 40h. The reference pin 10c is rotatably supported on the other side by three guide rollers 20r (not shown) provided on the side plate 40b of the main body with the flange 10b. At the same time as mounting the photoconductor drum 10 on the device body,
Gears 10 formed on the outer periphery of the flange 10b of the photosensitive drum 10.
g is meshed with the drive gear 40g on the apparatus main body side, and the power thereof drives the photosensitive drum 10 to rotate.

On the holding member 20 which is contained by the photosensitive drum 10 and fixed to the main body of the apparatus, an image exposing means is provided.
For example, exposure optical systems 12Y, 12M, 12C and 12K, or uniform exposure means such as pre-charging exposure device 12
3, transfer simultaneous exposure device 124, a light detection means, for example,
A photo sensor 125 and the like are attached, and a protective pipe 191 is rotatably supported on its outer periphery by protective pipe receiving portions 40m and 40n provided at both end portions of the holding member 20. When the photoconductor drum 10 is inserted, the slit 193 of the protection pipe 191 as shown in FIG.
It is located at the exposure openings of 12Y, 12M, 12C and 12K, and enables exposure to the photosensitive drum 10.

The drive lever 181 of the protective pipe whose fulcrum shaft 181a is rotatably supported by the drive lever fulcrum bearing 184 is counterclockwise about the fulcrum shaft 181a by a spring (not shown) as shown in FIG. 8A. In response to the force, the roller a182 provided at one end of the drive lever 181 causes the flange 10b of the photosensitive drum 10 to move.
Is in contact with Vertical shaft 1 at the other end of drive lever 181
Reference numeral 83 is fitted in a slide groove 192 provided in the protection pipe 191, and holds the photosensitive drum 10 as a holding member as shown in FIG. 8B.
When pulled out from 20, the roller a182 rotates counterclockwise while contacting the flange 10b of the photosensitive drum 10 by the force of the spring, and at the same time, the vertical shaft 183 presses the left end surface 192b of the slide groove 192, The protection pipe 191 is rotated counterclockwise, and the slit 193 of the protection pipe 191 is inserted into the exposure optical system 12Y,
Rotate from the 12M, 12C and 12K exposure openings to close them. When inserting the photoconductor drum 10, the flange 10b
However, when the roller a182 is pressed against the force of the spring, the vertical shaft 183 rotates clockwise while pressing the right end surface 192a of the slide groove 192, and rotates the protective pipe 191 rightward to move the protective pipe 191 to the right. The slit 193 is rotated above the exposure openings of the exposure optical systems 12Y, 12M, 12C and 12K to be in an open state.

Next, an embodiment according to the second and third aspects of the present invention will be described with reference to FIGS. 9 and 10. FIG.
FIG. 4 is a schematic view showing a portion using antireflection means,
10 is a diagram in which a light blocking member is provided in the exposure optical system.

Image exposure means provided on the holding member 20, for example, exposure optical systems 12Y, 12M, 12C and 12K.
Or a photosensitive drum which is an image forming body from the uniform exposure means.
In order to prevent a ghost due to the reflection of the exposure light inside 10, as shown in FIG. 9A, an antireflection means for preventing irregular reflection of the exposure light is provided at the inner end of the photoconductor drum 10.
Provide 10e (hatched area). As the antireflection means 10e,
For example, a black flocking material having a color that absorbs exposure light, a black cloth, or the like is attached, flocking is performed on the photosensitive drum itself, or an antireflection film is coated with a paint. Similarly, as shown in FIG. 9B, the holding member 20 is also provided with antireflection means 20e (hatched portion),
As the antireflection means 20e, for example, a black flocking material or black cloth having a color that absorbs exposure light is attached, or flocking is performed on the photosensitive drum itself, or an antireflection film is coated with a paint. Things are used. In either case, as a general rule, it may be one that absorbs the exposure light, but since it uses light of various wavelengths and there is light leakage from the outside, it is particularly necessary to perform black treatment or a black member. Is preferably used.

Further, as shown in FIG. 10, the exposure optical system 12
Y, 12M, 12C and 12K, a pre-charging exposure device 123 as a uniform exposure means, a transfer simultaneous exposure device 124, a photosensor as a light detection means, and an exposure opening portion such as a photosensor. Light-shielding members 126Y, 126M, 126C, 126K, 12 which absorb the exposure light on the outside and are preferably coated in black
3a, 124a, 125a are provided to improve the directivity. As described in FIGS. 9 and 10, the antireflection means 20e and the light blocking member 126 for enhancing the directivity are applied to the inside and the outside of the protective cover 163 in black in the previous embodiment.
It can have a role as Y, 126M, 126C, 126K, 123a, 124a, 125a. Further, a black antireflection member 127Y, 127M, 12 that absorbs the exposure light is provided outside the photoconductor drum 10 at a right angle to the exposure portion, facing the exposure portion.
7C, 127K and 123b are provided to prevent scattering of exposure light. Antireflection members 127Y, 127M, 127C, 127K and
As 123b, for example, a black flocked material, a plate material to which a black cloth or the like is attached, or a flocked material on the plate material itself, preferably an antireflection film coated with a black paint is used. The antireflection member is not only the exposure optical system but also the pre-charging exposure device 123, the transfer simultaneous exposure device 1
It is also applicable to exposure means such as 24 and photo sensor 125.

[0041]

According to the first aspect of the present invention, the protective cover is opened / closed according to the attachment / detachment of the photoconductor drum as the image forming body, and the exposure optical system as the image exposing means or other exposing means is used. There is a pre-charging exposure device as a uniform exposure means, a simultaneous transfer exposure device, and a photo sensor as a light detection means that matches and retracts the exposure portion opening to protect the exposure portion. In this state, the image exposure unit and the exposure unit are prevented from being scratched, damaged, or the like caused by dirt or contact with a member due to toner or dust. In addition, when the photosensitive drum is inserted or removed, the protective pipe, which is the protective cover provided on the outer periphery of the holding member, is rotated inside the photosensitive drum, and the position of the slit provided on the protective pipe is image-exposed. The exposure optical system, which is a means, and other parts, such as a pre-charging exposure device, a transfer simultaneous exposure device, and a photosensor, are aligned with and retracted from the exposure part to protect the exposure part and prevent stains and scratches.

According to the second or third aspect of the invention, the antireflection means is provided at the inner end of the photoconductor drum or the holding member of the exposure optical system, so that the inside of the photoconductor drum as an image forming body is provided. To prevent ghosts due to the reflection of exposure light. In addition, an exposure optical system as an image exposure unit, and other exposure units such as a pre-charging exposure device as a uniform exposure unit, a transfer simultaneous exposure device, and a photosensor as a light detection unit are used as an exposure unit opening. By providing a light-shielding member in parallel with the exposure light, the directivity of the exposure light can be enhanced, and by disposing a black antireflection member facing the exposure section on the outside of the photosensitive drum, Prevents the scattering of exposure light,
As a result, a latent image on the photosensitive drum is properly formed, and a color image forming apparatus capable of high-quality image recording is provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of a color image forming apparatus of the present invention.

FIG. 2 is a main part diagram of the color image forming apparatus of FIG.

FIG. 3 is a diagram showing a state when a photosensitive drum is pulled out.

FIG. 4 is a diagram showing a state in which a photosensitive drum is attached.

FIG. 5 is a diagram showing an opened / closed state of a protective cover.

FIG. 6 is a diagram showing a state in which a photosensitive drum according to another embodiment is attached.

7 is a diagram showing a positional relationship between an exposure unit and a protection pipe in the state of FIG.

FIG. 8 is a diagram showing an operating state of a drive lever of a protection pipe when a photosensitive drum is attached and detached.

FIG. 9 is a schematic view showing a portion using antireflection means.

FIG. 10 is a diagram in which a light blocking member is provided in the exposure optical system.

[Explanation of symbols]

10 Photoconductor drums 10a, 10b Flange 10c, 10d Reference pins 10e, 20e Antireflection means 11Y, 11M, 11C, 11K Scorotron charger 12Y, 12M, 12C, 12K Exposure optical system 13Y, 13M, 13C, 13K Developer 15 Supply Paper cassette 16 Timing roller 17 Fixing device 19 Cleaning device 20 Holding member 20b, 40i Reference hole 20r Guide roller 40a, 40b Side plate 40m, 40n Protective pipe receiving part 123 Pre-exposure exposure device 124 Transfer simultaneous exposure device 125 Photosensor 126Y, 126M, 126C, 126K, 123a, 124a, 125a
Light-shielding member 127Y, 127M, 127C, 127K, 123b Anti-reflection member 153 Open / close lever 157 Open / close pin 163 Protective cover 164 Bending part 181 Drive lever 191 Protective pipe 193 Slit P Transfer paper

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G03G 15/04 21/00 350 15/047 G03G 21/00 365

Claims (9)

[Claims] 1. A plurality of sets of charging means, an image exposing means and a developing means included in the image forming body are arranged around the image forming body, and the image forming body is charged by the charging means. A protective cover that is openable and closable in a color image forming apparatus that repeats image exposure by the image exposure unit and development by the developing unit to form toner images on the image forming body, and then collectively transfers the toner images onto a transfer material. The image exposing means, a uniform exposing means for exposing the image forming body, or
A color image forming apparatus provided in at least one of light detecting means. 2. The color image forming apparatus according to claim 1, wherein the protective cover is opened / closed in association with the attachment / detachment operation of the image forming body. 3. The color image forming apparatus according to claim 1, wherein the protective cover is provided on a holding member that holds the image exposing unit, the uniform exposing unit, or the light detecting unit. 4. A plurality of sets of charging means, an image exposing means and a developing means included in the image forming body are arranged around the image forming body, and the image forming body is charged by the charging means. In a color image forming apparatus that repeats image exposure by the image exposure unit and development by the developing unit to form toner images on the image forming body and then collectively transfers the toner images onto a transfer material, an antireflection unit is provided. A color image provided on at least one of the edge portion of the image forming body, the image exposing means, the uniform exposing means for exposing the image forming body, or the holding member holding the light detecting means. Forming equipment. 5. The color image forming apparatus according to claim 4, wherein the antireflection means is black paint. 6. A light blocking member is provided in at least one of the image exposure unit, the uniform exposure unit, and the light detection unit in parallel with the exposure light toward the image forming body. The color image forming apparatus according to claim 4. 7. The color image forming apparatus according to claim 6, wherein the light shielding member is coated to prevent reflection. 8. A plurality of sets of charging means, an image exposing means and a developing means included in the image forming body are arranged around the image forming body, and the image forming body is charged by the charging means. In the color image forming apparatus, the toner image is superposed on the image forming body by repeating the image exposure by the image exposing means and the developing by the developing means, and then the toner images are collectively transferred to a transfer material. Opposing at least one of the image exposing means included in the image forming body, the uniform exposing means for exposing the image forming body, or the light detecting means outside, to the exposure light toward the image forming body. Then, the color image forming apparatus is provided with an antireflection member. 9. The color image forming apparatus according to claim 8, wherein the antireflection member is painted black.