JP3321687B2 - Color image forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic apparatus in which a plurality of charging means, an image exposing means and a developing means are arranged on a peripheral surface of an image forming body and a toner image is formed by superimposing 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 of forming a multicolor image, a photoreceptor, a charger, a developing device and the like are provided in the same number as the required number of images, and a monochromatic toner image formed on the photoreceptor is transferred to a transfer member. (A) which is a color image that is superimposed on
An apparatus (B) for forming a color image by repeating charging, image exposure, and development for each color by rotating one photoconductor a plurality of times, or charging, image exposure, and the like for each color within one rotation of one photoconductor. An apparatus (C) for forming a color image by sequentially performing development is known.

However, the above-mentioned apparatus (A) has a drawback that the volume of the apparatus is increased due to the necessity of transporting a plurality of photoconductors and transfer bodies. On the other hand, the apparatus (B) has a charging means, an image exposure means and a photoconductor. Since there is only one, the volume is reduced, but there is a restriction that the size of the formed image is limited to the surface area of the photoconductor or less.

Although the apparatus (C) enables high-speed image formation, it is necessary to dispose a plurality of sets of a charger, an image exposing means and a developing unit in one circumference of a photoreceptor, and an optical system for exposing an image. The image quality may be impaired due to contamination of the toner leaking from the developing unit close to the system, and it is necessary to increase the distance between the image exposing means and the developing unit to avoid this. There is a contradiction of increasing the size of the device.

For the purpose of avoiding the drawbacks of the above-mentioned obstacles in the apparatus (C), the base of the image forming body is formed of a transparent material, and a plurality of image exposure means are accommodated in the inside thereof to print the image. A device in which a photosensitive layer formed on the outer periphery of the substrate is exposed through the above substrate has been proposed (for example, JP-A-5-307307).

[0006]

As is well known, the image forming body is driven and rotated at the time of image formation, and is provided with a fixed use period and is replaced at a predetermined time or undergoes maintenance or the like. It is incorporated in a structure that can be removed alone.

On the other hand, the image exposing means is always kept stationary, its use period is remarkably longer than that of the image forming body, and there is also a structural reason that it is installed inside the image forming body. In many cases, it is fixed directly to the apparatus body.

Therefore, each time the image forming body is attached to and detached from the apparatus main body, the operation of setting the position of the image exposure means with respect to the optical system is repeated, and even if the position is regulated with high mechanical precision, it cannot be ignored optically. The image distance may fluctuate or the optical system may be damaged, thereby reducing the sharpness of the image. Further, the optical system may be contaminated by toner or the like.

The present invention has solved and improved this point,
In recent years, taking into account the use of a photoconductor having a relatively long life, it has been realized that the image forming unit is integrated with the image exposing means included therein, thereby changing the image forming distance of the optical system, It is an object of the present invention to provide a color image forming apparatus capable of recording high-quality images by eliminating contamination and contamination.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to dispose a charger and a developing device on the outer edge of a photosensitive drum, and a plurality of exposure optical systems inside the photosensitive drum. In a color image forming apparatus in which a toner image is superposed and formed on the photosensitive drum by repeating image exposure by a system and development by a developing device and then collectively transferred onto transfer paper, a plurality of the exposure optical systems are provided on a support member. Arranged in
The support member has a support shaft at one end and three guides at the other end.
Rollers are provided, flanges are integrated on both side ends of the photosensitive drum, and a bearing member rotatable with respect to the support shaft is provided at the center of one flange, and the other flange inner surface is A cylindrical surface on which three guide rollers abut, and the photosensitive drum is rotatable with respect to the support member
And a cartridge in which the photosensitive drum, the support member, and the cylindrical housing are integrated into a cartridge housed in a cylindrical housing for internal protection, and the cartridge is a guide parallel to a support shaft provided in the apparatus main body. It is detachable along the rail,
A gear formed on the outer periphery of the flange is engaged with a gear provided on the apparatus main body side during the insertion, and the photosensitive drum is configured to rotate by a driving force of the main body side; Achieved by the device.

[0011]

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.

Numeral 10 denotes a drum-shaped image forming body, that is, a photosensitive drum. A transparent conductive layer, an a-Si layer or an organic photosensitive layer is formed on the outer periphery of a cylindrical substrate formed of a transparent member such as optical glass or transparent acrylic resin. (OPC).

Reference numeral 11 denotes a scorotron charger, which is a photosensitive drum 10
The above-described organic photoconductor layer performs a charging action by a grid maintained at a predetermined potential and a corona discharge by a discharge wire to give a uniform potential to the photoconductor drum 10.

Reference numeral 12 denotes FL, EL, PL, and L in which light-emitting elements arranged in the axial direction of the photosensitive drum 10 are arranged in an array.
ED or LI in which elements with optical shutter function are arranged in a line
An exposure optical system composed of SA, PLZT, LCS and a self-occurring lens as an equal-magnification imaging element. Image signals of respective colors read by a separate image reading device are sequentially taken out of a memory and read out by the above-mentioned respective components. Each is input to the exposure optical system 12 as an electric signal.

Each of the exposure optical systems 12 is mounted on a columnar support member 20 and housed inside the base of the photosensitive drum 10.

Reference numerals 13Y to 13K denote developers for accommodating yellow (Y), magenta (M), cyan (C), and K (black) developers, each having a predetermined gap with respect to the peripheral surface of the photosensitive drum 10. Developing sleeve 13 that rotates in the same direction while maintaining
It has 0.

Each of the developing units is brought into a non-contact state by applying a developing bias voltage to the electrostatic latent image on the photosensitive drum 10 formed by the charging by the charger 11 and the image exposure by the exposure optical system 12. To reverse development.

Next, the process of the color image forming apparatus in the present apparatus will be described.

An original image is read by an image reading apparatus separate from the present apparatus, and an image read by an image sensor or an image edited by a computer is once converted into image signals for respective colors of Y, M, C and K. Stored and stored in memory.

The photosensitive drum 10 is rotated clockwise by the start of the photosensitive member drive motor at the start of image recording,
At the same time, the charging action of the charger 11 (Y) causes the photosensitive drum 10
Is started.

After the photosensitive drum 10 is applied with a potential,
The exposure optical system 12 (Y) starts exposure with an electric signal corresponding to a first color signal, that is, an image signal of yellow (Y), and the rotation of the drum scans the yellow (Y) of the original image on the photosensitive layer on its surface. A) to form an electrostatic latent image corresponding to the image of FIG.

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

Next, the photosensitive drum 10 is further provided with a potential on the yellow (Y) toner image by the charging action of the charger 11 (M), and the second color signal of the exposure optical system 12 (M), ie, Exposure is performed using an electric signal corresponding to the magenta (M) image signal, and the magenta (M) toner image is superimposed on the yellow (Y) toner image by non-contact reversal development by the developing device 13 (M). Are sequentially superimposed and formed.

According to the same process, the toner image of cyan (C) corresponding to the third color signal is further charged by the charger 11 (C), the exposure optical system 12 (C) and the developing device 13 (C). 11 (K), exposure optical system 12 (K) and developing unit 13
By (K), a black (K) toner image corresponding to the fourth color signal is sequentially superimposed, and a color toner image is formed on the peripheral surface within one rotation of the photosensitive drum 10.

The photosensitive drum 10 using each of these exposure optical systems
Exposure to the organic photosensitive layer is performed from the inside of the drum through the transparent substrate described above. Therefore, the exposure of the images corresponding to the second, third, and fourth color signals is performed without any influence from the previously formed toner image, and the first exposure is performed.
It is possible to form an electrostatic latent image equivalent to an image corresponding to the color signal. In order to stabilize the temperature in the photosensitive drum 10 and prevent the temperature from rising due to heat generated by each exposure optical system 12, a material having good thermal conductivity is used for the support member 20, and a heater is used at a low temperature, and a heater is used at a high temperature. In the case of (1), measures such as radiating heat to the outside through the heat pipe can be suppressed to a level that does not cause any trouble. In the developing operation by each developing device, a developing bias in which a direct current or further alternating current is applied to the developing sleeve 130 'is applied, and a jumping development is performed by a one-component or two-component developer contained in the developing device. A non-contact reversal development is performed in which a direct current bias having the same polarity as that of the toner is applied to the photosensitive drum 10 that grounds the transparent conductive layer and the toner adheres to the exposed portion.

The color toner image formed on the peripheral surface of the photoreceptor drum 10 is transferred from the paper feed cassette 15 in the transfer unit 14A and transferred to the transfer paper fed in synchronization with the driving of the timing roller 16. You.

The transfer paper to which the toner image has been transferred is removed from the transfer paper.
At 14B, the toner is separated from the peripheral surface of the drum in response to the removal of the charge, the toner is welded in the fixing device 17, and then discharged onto a tray at the upper portion of the device via a discharge roller 18.

On the other hand, the photosensitive drum 10 from which the transfer paper has been separated removes and cleans the residual toner in the cleaning device 19 to continue forming the toner image of the original image, or temporarily stops and forms a new toner image of the original image. The formation of

The photosensitive drum 10 has a plurality of chargers 11 and a developing unit 13 on the outer peripheral surface thereof even if the diameter of the drum is relatively small because the exposure optical system is housed in the photosensitive drum 10. It is possible to have an outer diameter of 60mm to 150mm
The use of the small-diameter drum makes it possible to make the volume of the apparatus compact.

Further, the developing units 13 (M) and 13 (C), the developing units 13 (C) and 13 (C) with respect to a vertical line MON passing through the center O of the photosensitive drum 10.
13 (Y) and 13 (K) are symmetrically positioned, respectively,
(Y) and 13 (K) are arranged at a substantially horizontal symmetrical position passing through the center O, and the cleaning device 19 is positioned at an angle θ1 of 5 degrees or less on the downstream side of the rotation of the drum with respect to the lower vertical line ON.
By installing the transfer unit 14A at the position where the angle θ2 is 25 ° to 65 ° on the upstream side of rotation on the other hand, the space around the drum peripheral surface is effectively used, and the transfer unit 14A is compact and shaped.
A balanced layout can be obtained with respect to both weight distribution and the photosensitive drum 10 and the exposure optical system 12 as described later.
Can be integrated including the charger 11, the cleaning device 19, and the developing device 13.

(Embodiment 1) An embodiment of the first invention of the present invention will be described with reference to FIGS.

FIG. 3 is a cross-sectional view of the photosensitive drum 10 in the direction of the rotation axis, and FIG. 4 is a side cross-sectional view at AOA.

The photosensitive drum 10 has flanges 10A at both ends.
10B is integrated, and the flange 10A is supported by a support shaft 20A protruding from the axis of the support member 20 of the exposure optical system 12,
On the other hand, the flange 10B is rotatably supported by three guide rollers 20R provided on the flange portion 20B of the support member 20.

The photosensitive drum 10 and the support member 20 are housed in a cylindrical protective cover 30 fixedly engaged with the support shaft 20A and the flange portion 20B of the support member 20 to form an integral unit U. The support shaft 20A protruding from the front surface and the engaging portion 20C behind the flange portion 20B are connected to the substrates 40A and 40B of the apparatus main body.
Are fixed to the substrate 40B side via screws while being engaged with and positioned respectively.

Accordingly, the photosensitive drum 10 and the exposure optical system 12 are integrally handled as a unit U. As a result, the image forming distance of the optical system with respect to the photosensitive layer is always kept constant without fluctuation.

The protective cover 30 integrally accommodates the charger 11 and the cleaning device 19 together with the photoreceptor drum 10, and forms a concave surface 30B along the drum surface between the chargers 11 and the cleaning device 19.
The concave portion 30B is provided with an opening 30C for making the developing device 13 or the transfer device 14A, the static eliminator 14B, and the like face the photosensitive surface.

Each of the developing units 13, the transfer unit 14A, and the static eliminator 14B are installed at predetermined positions after the unit U is mounted on the apparatus main body.

It should be noted that the unit U can be expanded to accommodate the respective developing units 13 so as to be integrated, and conversely, only the photosensitive drum 10 and each exposure optical system 12 can be integrated. You may do.

The unit U is mounted on the main body of the apparatus,
Gear 10 formed on the outer periphery of flange 10B of photoreceptor drum 10
G is meshed with a drive gear 40G on the apparatus main body side, and the photoreceptor drum 10 is driven and rotated by its power.

FIG. 7 is a perspective view showing the appearance of the unit U.

(Embodiment 2) An embodiment of the second invention of the present invention will be described with reference to FIGS.

FIG. 5 is a sectional view of the photosensitive drum 10 in the direction of the rotation axis, and FIG. 6 is a sectional view taken along the line AOA.

The photosensitive drum 10 has flanges 10A on both sides.
10B is integrated, and the flange 10A is supported by a support shaft 20A protruding from the axis of the support member 20 of the exposure optical system 12,
On the other hand, the flange 10B is rotatably supported by three guide rollers 20R provided on the flange portion 20B of the support member 20.

The photosensitive drum 10 and the support member 20 are housed in a cylindrical housing 130 fixedly engaged with the support shaft 20A and the flange portion 20B of the support member 20 to form an integral cartridge C. The guide rails G provided on both side surfaces are slid and inserted into guide members (indicated by alternate long and short dash lines) on the side of the apparatus main body, and are engaged with the reference pins 40E and the cartridge C and with the engagement members (not shown). Substrates 40A and 40B of the device body
It is attached to a predetermined position between them. The cartridge C
Can be easily taken out of the apparatus by releasing the engagement of the locking member.

Accordingly, the photosensitive drum 10 and the exposure optical system 12 are integrally attached to and detached from the main assembly of the apparatus as a cartridge C. As a result, the image forming distance of the optical system with respect to the photosensitive layer is always constant without change. Will be kept.

The above-mentioned housing 130 integrally accommodates each of the chargers 11 and the cleaning device 19 together with the photoreceptor drum 10, and forms a concave portion 130B along the drum surface between the chargers 11 and the cleaning device 19.
The concave portion 130B is provided with an opening 130C for making the developing device 13 or the transfer device 14A, the static eliminator 14B and the like face the photosensitive surface.

The mounting and dismounting of the cartridge C is performed in a state where the developing units 13, the transfer units 14A, and the static eliminators 14B are retracted from the photosensitive surface of the photosensitive drum 10 and are separated in advance.

The above-mentioned cartridge C can be expanded to accommodate the respective developing units 13 so as to be integrated, and conversely, only the photosensitive drum 10 and each exposure optical system 12 can be integrated. You may do.

At the same time as the cartridge C is mounted on the apparatus main body, a gear 10G formed on the outer periphery of the flange 10B of the photosensitive drum 10 meshes with a drive gear 40G on the apparatus main body side to drive and rotate the photosensitive drum 10 by its power. State.

FIG. 8 is a perspective view showing the appearance of the cartridge C.

[0051]

According to the present invention, the image forming body and the image exposing means are always handled integrally, so that there is no change in the mutual positional relationship, and therefore, the image forming accuracy of the exposure optical system is stabilized.
As a result, a color image forming apparatus capable of recording high quality images with high resolution performance has been provided.

[Brief description of the 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 view of the device.

FIG. 3 is a sectional view of a unit according to the first invention.

FIG. 4 is a sectional view of a main part of the unit.

FIG. 5 is a sectional view of a cartridge according to the second invention.

FIG. 6 is a sectional view of a main part of the cartridge.

FIG. 7 is an external perspective view of the unit.

FIG. 8 is an external perspective view of the cartridge.

[Explanation of symbols]

 10 Photoreceptor drum 10A, 10B Flange 11 Charger 12 Exposure optical system 13 Developing unit 14A Transfer unit 14B Static eliminator 15 Paper cassette 16 Timing roller 17 Fixing device 18 Discharge roller 19 Cleaning device 20 Support member 20A Support shaft 20B Flange 20C Engagement part 20R Guide roller 30 Protective cover 40A, 40B Main board 40G Drive gear 130 Housing G Guide rail

Continuation of the front page (56) References JP-A-5-323757 (JP, A) JP-A-3-259271 (JP, A) JP-A-5-323689 (JP, A) JP-A-2-198466 (JP) JP-A-5-307307 (JP, A) JP-A-5-265262 (JP, A) JP-A-4-335654 (JP, A) JP-A-2-123377 (JP, A) 3-56977 (JP, A) JP-A-64-76076 (JP, A) JP-A-7-248715 (JP, A) JP-A-7-253697 (JP, A) JP-A-7-261495 (JP, A A) JP-A-7-306579 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/00 550 G03G 21/16-21/18 G03G 15/01 G03G 15/04 G03G 21/00 350-352

Claims (3)

(57) [Claims] 1. A charging device and a developing device are arranged on an outer edge portion of a photoconductor drum, and a plurality of exposure optical systems are arranged inside the photoconductor drum. In a color image forming apparatus which repeats development to form a toner image on the photosensitive drum in a superimposed manner and collectively transfers the toner image onto transfer paper, a plurality of exposure optical systems are provided on a support member, Has a support shaft at one end, and three guide rollers at the other end, and a flange is integrated with both ends of the photosensitive drum, and the support shaft is provided at the center of one of the flanges. provided a bearing member which is rotatable relative to, said other flange inner surface 3
The photosensitive drum is rotatably supported by the support member.
The cartridge is housed in a cylindrical housing for internal protection, and is integrated with the photosensitive drum, the support member, and the cylindrical housing. The cartridge is mounted on a guide rail parallel to a support shaft provided on the apparatus main body. The gears formed on the outer periphery of the flange are in meshing engagement with the gears provided on the apparatus main body side at the time of insertion, so that the photosensitive drum is rotated by the driving force of the main body side. A color image forming apparatus, comprising: 2. The color image according to claim 1, wherein at least one of the charging device, the developing device, and the cleaning unit is attached to the housing and is integrated with the cartridge. Forming equipment. 3. The exposure optical system and the developing device are arranged two each on the left and right sides of a vertical line passing through the center line of the photosensitive drum, and a cleaning unit is provided at a rotation downstream position below a vertical line position, and a rotation upstream unit. 3. The color image forming apparatus according to claim 1, wherein a transfer unit is disposed at a side position.