JPH02158756A - Process cartridge and image forming device - Google Patents

Abstract

PURPOSE:To shield the inside of a main cartridge including a latent image carrier from external environment which has adverse effect on the cartridge by covering a part where a sub cartridge is loaded with a covering member when the sub cartridge is taken out from the main cartridge. CONSTITUTION:The covering member 31 is energized to be turned by a tension spring 37 with a shaft pin 33 as a center and a color developing device 3 which is the sub cartridge is pressurized and energized toward a photosensitive drum 1 by pressing a back surface by means of a pressurizing knob 53. therefore, the sub cartridge 3 is taken out just opening the covering member 31 and the covering member 31 is turned with the tensile force of the tension spring 37 when a user releases the covering member 31 in a state where the sub cartridge 3 does not exist in the main cartridge A in the exchanging operation of the sub cartridge 3. Thus, the inside of the main cartridge A including the photosensitive drum 1 is protected from the external environment which has the adverse effect on the cartridge at the time of exchanging the sub cartridge 3.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a process cartridge that is removably installed in the main body of an image forming apparatus using electrophotography, and particularly relates to a process cartridge that is removably installed in the main body of an image forming apparatus using electrophotography, and in particular, a process cartridge that is attached to an electrostatic latent image carrier (photosensitive drum). The present invention relates to a cover mechanism that protects the inside of a process cartridge, including a process cartridge, from the outside.

(Prior Art) At present, many printers that serve as terminal devices for information equipment such as computers, facsimiles, and CAD are based on electrostatic recording using electrophotography.

In these printers, image information signals are written on an electrostatic latent image carrier, that is, a photosensitive drum, using a laser beam, LED, LCD, etc., and this is visualized by a developing device, and then transferred and fixed to form a recorded image. I'm trying to get it. In this case, the most typical recorded image formed on a recording paper by a printer is one color, for example, black.

However, recently, in order to make the recorded image clearer or to make the image information easier to understand, the color of the recorded format and the color of the calculated value or data value are expressed in different colors. It is desired to differentiate using two or more colors, such as outputting a part of a drawing output by CAD in another color.

FIG. 11 is a schematic diagram of an electrophotographic apparatus that enables two-color recording.

In the figure, a drum-shaped electrophotographic photosensitive member (hereinafter simply referred to as a photosensitive drum) 101, which is formed by coating a photoconductive layer on an electrostatic latent image carrier, that is, a conductive substrate, is rotatably held. A charger 10 arranged around the
2, the photosensitive drum 1 is uniformly charged, and then a first optical information signal 103 emitted from a light emitting element such as a semiconductor laser is applied to the photosensitive drum 1.
The charged surface of 01 is irradiated and exposed to form a first electrostatic latent image, and the first developed ? At tW104, toner is attracted to the latent image pattern and visualized. Thereafter, the photosensitive tram 101 is charged again by the charger 105, and a second optical information signal 10 is similarly emitted from a light emitting element such as a semiconductor laser.
6 to form a second electrostatic latent image, and the second developing device 107 attracts toner to the latent image pattern to visualize it.

Next, the paper 10 is placed in contact with the developing peripheral surface of the photosensitive drum 101.
The toner pattern on the photosensitive drum 101 is transferred to the paper 108 by applying static electricity opposite to that of the toner with the transfer device 109 to the back side of the photosensitive drum 8, and the toner transferred to the paper 108 is further pressed by the fixing device 110 to fix it. do.

Further, untransferred toner remaining on the photosensitive drum 101 is removed by a cleaning device 111, and the untransferred toner remaining on the photosensitive drum 101 is removed by a cleaning device 111.
Clean the peripheral surface of 1.

As described above, when an electrophotographic device is used for a long time, it becomes necessary to replace the photosensitive drum, replenish or replace the developer, clean the charging wire, and adjust or replace other parts. This will be done by a professional service person. However, methods have been proposed that allow electrophotographic apparatuses to operate in good condition at all times by performing maintenance work without relying on service personnel with specialized knowledge.

For example, there is a method in which a plurality of process means such as a discharger, a developer, and a photosensitive drum included in the apparatus are combined into a cartridge, and this cartridge is simply replaced with a new one. By configuring the process cartridge to be replaceable in this way, the device can be used immediately for maintenance, repair, and replacement of consumables by simply replacing the process cartridge with a new one. It is.

However, in electrophotographic equipment that performs multicolor printing,
Because the amount of toner consumed by each color developing device is different,
Incorporating each developing device into the same process cartridge has the problem that when one developing device runs out of toner, the usability value of the process cartridge itself is halved.

In addition, for users who usually print images in only one color such as black, and print images in other colors only for special purposes, it is recommended to install two developing devices in the same process cartridge and use a cartridge with both. Providing multiple types for each color becomes expensive.

Therefore, conventionally, there is a method of making one or more developing devices replaceable among two or more developing devices incorporated in the same process cartridge.

(Problem to be Solved by the Invention) As described above, in the conventional process cartridge in which the developing device is replaceable, when the developing device is replaced, the peripheral surface of the photosensitive drum that was covered by the developing device is exposed to light. Therefore, when replacing the developing device, it is necessary to prevent the peripheral surface of the photosensitive drum from being damaged or dust to adhere to it, and to avoid exposing the photosensitive drum to strong light such as direct sunlight. be. However, if it takes time to replace the developing device for the process cartridge, or if the replacement work has to be temporarily suspended, the photosensitive drum may be exposed to a strong light atmosphere for a long time. In addition, there is a risk that the process cartridge may become a defective product, and there is also a risk that the dust may damage the peripheral surface of the drum, making the process cartridge difficult to handle.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to reliably protect the inside of the main cartridge including the photosensitive drum from the external environment that adversely affects it when replacing the sub-cartridge. The purpose of the present invention is to provide a process cartridge that can improve replaceability and handling.

(Means for Solving the Problems) The process cartridge according to the present invention covers the mounting portion of the sub-cartridge when the replaceable sub-cartridge is taken out from the main cartridge constituting the process cartridge, thereby shielding the inside of the main cartridge from the outside. The cover member is biased toward the position covering the sub-cartridge.

(Function) According to the eighth aspect of the present invention, when the sub-cartridge is attached to the main cartridge, the cover member is retracted to a position where it does not interfere with image formation on the latent image carrier, and the sub-cartridge is removed from the main cartridge. In this case, the cover member covers the mounting portion of the sub-cartridge to shield the interior of the main cartridge including the latent image carrier from external environments that may have an adverse effect on the main cartridge.

Accordingly, one object of the present invention is to protect the inside of the main cartridge including the latent image carrier from the external environment that adversely affects it when replacing the sub-cartridge, and to improve the ease of replacing the sub-cartridge and handling the process cartridge. become.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

" 3 is a schematic cross-sectional view of the process cartridge of this embodiment applied to a laser beam printer, and FIG. 4 is a schematic cross-sectional view of the laser beam printer with its front panel opened. be.

In FIGS. 1 and 2, reference numeral 1 denotes a process cartridge, which is equipped with a photosensitive tram 1 constituting an electrostatic latent image carrier, which is a process device for image formation. A first charger 2, a color developing device 3, which are process equipment. A second charger 4, a negligible image device 5, and a cleaning device 6 are arranged along the rotational direction of the photosensitive drum 1, among which the color developing device M3 constitutes a sub-cartridge, and other process equipment (symbol l , 2, 4.5° 6) constitutes the main cartridge.

The sub-cartridge is detachably attached to the main cartridge, and the entire cartridge constitutes a duplex process cartridge.

Further, 26 is a housing of the main cartridge, and a part of the transfer side (right side in FIG. 1) is opened.
(Only one side is shown in FIG. 1) The stay 26 is inserted between the two, thereby reinforcing the side plate 27.

Inside the housing 26 thus configured, a photosensitive tram l constituting the main cartridge is disposed toward the opening side of the housing 26.
is arranged, and both ends of the rotation center axis IA of the photosensitive drum l are rotatably supported by the left and right side plates 27.2.

The first and second chargers 2 and 4 are arranged in a predetermined positional relationship on the anti-transfer side of the photosensitive drum 1, and are fixed to the housing 26 by a support member (not shown).

Moreover, the ignored image device 5 constituting the main cartridge is
The developing device main body 5B is located downstream of the second charger 4, and its left and right side plates are connected to the housing 26.
Support pins 28a and 28 fixed to the left and right side plates 27 and 27 of
b (see Figures 1 and 2)
The developing device main body 5B is supported so as to be swingable in the direction of arrow G in the figure, and spring hook pins 5a (only one is shown) are provided on the left and right side plates on the swing end side of the developing device main body 5B. Each pair of left and right spring hooks of the housing 26 facing the housing 26 is provided with a tension spring (only one shown) between the pins 5a and 29, so that the ignored image ff
15 in the clockwise direction in FIG. 1 around the support pins 28a and 28b, so that the developing sleeve 5A (or a spacer roller (not shown)) is constantly pressed against the circumferential surface of the photosensitive drum 1 with a predetermined pressure. .

The cleaning device 16 constituting the main cartridge is located upstream of the first charger 2 and is provided integrally with the housing 26, and has a cleaning plate 6A, the tip edge of which touches the circumferential surface of the photosensitive drum l. The toner remaining on the circumferential surface of the photosensitive drum 1 is removed.

1 and 2, reference numeral 31 is a cover member constituting the main part of this embodiment, and this covers the color developing device t3 as a sub-cartridge to the main cartridge housing 31.
The opening 26A for insertion into and removal from the photosensitive drum 6 is opened and closed, and the circumferential surface of the photosensitive drum l facing the opening 26A is protected.

Both left and right ends of the base of the cover member 31 are pivotably connected to a supporting portion 32 protruding from the partition wall 6B of the cleaning device 6 by shaft pins 33 (only one of which is shown in the figure) so as to be openable and closable. ,and.

A tension spring 37 is tensioned on the pin 34 provided on the pivot base side of the cover member 31 and the spring hook protruding from the partition wall 6B (or other immovable member). 31 is always biased in the closing direction to rotate toward the photosensitive drum 1 side. Said pin 34. The spring hook member 36 and the spring 37 are provided on the left and right sides corresponding to the left and right pivot parts of the cover member 31.

The color developing device 3, which is located inside the cover member 31 and inserted into and removed from the housing 26, has sub-cartridge inserts formed symmetrically on the left and right side plates 27 and 27 of the housing 26, respectively, as shown in FIG. Notch guide for removal guide Y446
It further includes a guide pin 43 that engages with the developing sleeve 3.
It has a shirt flap plate 45 as a cover member that protects the outwardly exposed surface of A (the surface that comes into contact with the photosensitive drum l). ) is pivotally connected to the main body of the color developing device, and is further biased by a biasing spring 45b (number M in the second figure) in a direction to always close the outwardly exposed surface of the developing sleeve 3A. Also.

Reference numeral 45c denotes a shirt flap opening lever connected at right angles to the pivot pin 45a of the shirt flap plate 45, and a pin 45d is provided at the tip thereof protruding at right angles.

In FIG. 1, 48 indicates the left and right side plates 2 of the housing 26.
7. A cam member 48 for opening and closing the shutter is provided symmetrically to the housing 26.
Pin 4 of the shirt shutter opening lever 45c when the shirt is installed inside the
5d is engaged to open the shirt flap plate 45.

In FIG. 1, reference numeral 51 indicates an entrance hole formed in the cover member 31 for injecting the exposure laser beam Ll that forms a latent image for a color image onto the photosensitive drum l; This is an entrance opening formed in the housing 26 to receive the exposure laser beam L2 that creates a latent image. Further, 53 is a pressure knob provided on the inner surface of the cover member 31, and this pressure knob 53 comes into pressure contact with the back surface of the color developing device 3 to stably hold the color developing device 3 installed in the housing 26. That's what I do.

Next, the operation of inserting and removing the sub-cartridge configured as described above will be described.

FIG. 1 shows a state in which a color developing device 3 as a sub-cartridge is properly installed in the main cartridge.

In this state, the guide pin 43 on the one-color developing device 3 side is engaged with the notched guide groove 46 on the main cartridge side.

Moreover, the shirt top plate 45 is.

The pin 45 of the shutter lever 45q rides on the top surface of the cam member 48, and the lever 45c is moved by the spring 45 around the shaft 45a.
By rotating the developing sleeve 3A in the clockwise direction against the rotation angle b, the developing sleeve 3A is sufficiently released downward from the front side thereof, and the surface of the developing sleeve 3A facing the photosensitive member and the ram 1 is kept fully open.

On the other hand, the cover member 31 is urged to rotate clockwise around the shaft bin 33 by the tension spring 3F, and the pressure knob 53 is further pressed against the color developing device! By pressing the back side of the color developing device M3, the color developing device M3 is pressed toward the photosensitive tram l. That is, the color developing device W13, which is a sub-cartridge, is connected to the photosensitive drum 1.
Pressure is applied in the direction of . As a result, the developing sleeve 3A of the color developing device 3 (or the spacer rollers at both ends thereof) is always kept in contact with the photosensitive drum 1 at a predetermined pressure. In other words, the color developing device M as a sub-cartridge
3 is always stably held under pressure at a predetermined position relative to the photosensitive drum 1 on the main cartridge side. When taking out the sub-cartridge from the main cartridge, remove the process cartridge A from inside the printer in which it is installed (this operation will be described later), then insert the removed process cartridge A into the cover member 31 as shown in Figure 2. Place it on a work desk or stand with the side facing up.

Next, the cover member 31 is moved against the force of the spring 37 and the shaft pin 3 is
3 by hand in the direction of arrow H in Figure 2. This rotation of the cover member 31 in the direction of arrow H causes the pressure knob 53 to move away from the back surface of the color developing device M3 serving as a sub-cartridge, thereby releasing the pressurizing effect on the color developing device.

The cover member 31 is opened wide, and then the color developing device 3 as a sub-cartridge is grasped by hand from inside the main cartridge, lifted up from above, and pulled out. During this extraction process, the pin 45 of the shutter lever 45c on the color developing device side 3
d is removed from the cam member 48, the shutter plate 45 is rotated in the closing direction about the shaft 45a by the spring 45b, and the outer exposed surface of the developing sleeve 3A is automatically closed by the shirt flap plate 45.

Next, the color developing device 3 as a new sub-cartridge or the color developing device 3 as a sub-cartridge containing the required color developer is inserted into the main cartridge. Before insertion, the shutter plate 45 of the color developing device 3 is in a closed state, with the shirt flap 45 side facing downward, and the guide pins 43 on both the left and right sides of the color developing device t3 correspond to the guide grooves 46 on the main cartridge side, respectively. engage and insert into the main cartridge. During the insertion process, the shutter lever 4
5c is guided to the upper surface side of the cam member 48, so that the shutter lever 45c, that is, the shutter plate 45
is automatically fully opened and rotated clockwise about the pivot pin 45a against the spring 45b.

Next, when the force holding down the cover member 31 is loosened,
The cover member 31 rotates clockwise about the shaft pin 33 due to the tensile force of the tension spring 37, and finally reaches the same state as shown in FIG. 1. In this state, the pressure rib 5
The back side of the three-color developing device 33 is pressed against it. That is, the developing sleeve 3A (or the spacer rollers on both ends thereof) of the inserted color developing device is kept in constant pressure contact with the photosensitive drum 1.

In addition, when the sub-cartridge is installed in the main cartridge, the dimension between the inner surfaces of the left and right side plates 27 of the main cartridge's hanging 26 and the base dimension of the left and right guide pins 43 of the color developing device 3 as the sub-cartridge are almost the same. Therefore, the sub-cartridge is stably held without shifting or wobbling in the longitudinal direction of the photosensitive drum l.

In the above-described duplex process cartridge of this embodiment, the color developing device 3, which is a sub-cartridge, can be taken out by simply opening the cover member 31, and when assembling the sub-cartridge, the sub-cartridge is inserted into the main cartridge along the guide groove 46. After inserting the sub-cartridge into the cartridge and then closing the cover member 31, setting the sub-cartridge, that is, positioning it;
The pressure is maintained. Therefore, attachment and detachment of the sub-cartridge to and from the main cartridge becomes very simple and easy. In addition, when replacing the sub-cartridge, if the sub-cartridge is not in the main cartridge A and you release your hand from the cover member 31, the cover member 31 will rotate clockwise due to the tensile force of the tension spring 37. , the state is shown by the dotted line in FIG. In this state, the first charger 2, the second charger 3, and the photosensitive tram l are protected by the cover member 31. Furthermore, external light from the first exposure laser beam entrance port 52 is also prevented by the cover member 31, so that it does not directly irradiate the photosensitive drum l.

Therefore, when replacing the sub-cartridge, unless the operator consciously opens the cover member 31, the cover member 31 will be in a closed state, so if the replacement work has to be interrupted for some reason, Even if the replacement work takes time, the inside of the main cartridge cartridge is protected from foreign objects, dust, scratches, etc. from the outside by the cover member 31, so mistakes during replacement can be completely prevented. .

Further, since the sub-cartridge is housed within the main cartridge, the handling of the process cartridge A is not inferior to that of a single-type process cartridge without a sub-cartridge.

On the other hand, since the shutter member 45 for protecting the developing device automatically opens and closes in conjunction with the attachment and detachment of the developing device 3, which is a sub-cartridge, to the main cartridge, the operator does not have to be aware of this shutter member 45 when attaching and detaching the sub-cartridge. Can be done. The sub-cartridge itself is also easy to handle since the parts of the removed sub-cartridge that are not allowed to be directly touched by the operator and the parts that are easily soiled are hidden by the shutter member.

Next, the operation when the process cartridge A of this embodiment is installed in a printer and printed will be described based on FIG. 3.

In FIG. 3, a photosensitive drum 1, a first charger 2, a color developing device! ! 3. The process cartridge A, which includes the second charger 4, the ignored image device 5, and the cleaning device 6, is installed in the printer main body in a predetermined posture as shown in FIG.

When printing, a print start command signal is sent to the photosensitive drum l.
When input to the drive control circuit (not shown), the photosensitive drum l is rotated clockwise as indicated by the arrow at a predetermined circumferential speed.
The circumferential surface is uniformly charged by the first charger 2, and then a laser beam Ll corresponding to the first image information signal output from the laser scanner 7 is applied to the cover member 31 by mirrors 8 and 9. The photosensitive drum 1 is scanned and irradiated through the slit-shaped entrance port 51 of the photosensitive drum 1, thereby forming an electrostatic latent image corresponding to the first image information signal on the circumferential surface of the rotating photosensitive tram l. Color toner is developed by the color developing device 3 containing red toner.

Next, the peripheral surface of the photosensitive tram l is uniformly charged again by the second charger 4, and then a laser beam L2 corresponding to the second image information signal output from the laser scanner 7 is applied to the cartridge by a mirror 10.11. The peripheral surface of the photosensitive drum l is scanned and irradiated from the slit-shaped entrance 52 provided in the housing 26, thereby forming an electrostatic latent image corresponding to the second image information signal, and ignoring the latent image by the image device. 5 to develop black toner.

As a result, a two-color toner image consisting of a color toner developed image corresponding to the first image information signal and a black toner developed image corresponding to the second image information signal is formed on the circumferential surface of the rotating photosensitive drum 1. Ru.

On the other hand, one copy of the transfer paper P is taken out from the paper cassette 12 by the paper supply roller 13 and fed to the registration rollers 16 via the guide plate 14.15. The paper feed speed is synchronized with the circumferential speed of , and the paper is fed to a portion (image transfer portion) where the photosensitive drum 1 and the transfer charger 17 face each other. As a result, the two-color toner images formed on the circumferential surface of the photosensitive drum 1 are sequentially transferred onto the surface of the fed transfer paper.

The transfer paper that has passed through the image transfer section is separated from the circumferential surface of the photosensitive tram l and sent to the fixing device 19 by the conveying device 18.
After fixing the transferred toner image, guide 20. Paper ejection roller 21. The paper is sent out as a two-color print I via the paper ejection port 22 to the paper ejection tray 23.

After the image transfer, the peripheral surface of the photosensitive drum 1 is cleaned by a cleaning device 6 to remove residual toner after transfer and other contaminants, and the photosensitive drum 1 is repeatedly used for image formation.

In the printer of this embodiment, the right end side is the front side, as shown in FIG. It can be tilted and opened freely as shown in Figure 4. A guide plate 14 is installed inside this printer front plate 24.
15, and registration roller 16, transfer charger 17. A conveyance device 18 is provided and held, and by folding down and opening the printer front plate 24, the interior of the printer is wide open.

To install the process cartridge A into the printer, open the printer front plate 24 as shown in FIG. It is locked and held by a locking means. After closing the printer front plate 24 with respect to the printer main body, the process cartridge A is installed in a predetermined position in the printer main body in a predetermined attitude by locking it with the locking means as shown in FIG. state. Removal of the process cartridge A is performed by reversing the above procedure.

Figures 5 to 7 show a second embodiment of the process cartridge according to the present invention.

Fig. 5 is a sectional view of the process cartridge, Fig. 6 is a side view showing how the sub-cartridge is attached to and removed from the main cartridge, and Fig. 7 is a schematic sectional view when the process cartridge of this embodiment is applied to a laser beam printer. It is.

In this figure, the same or equivalent parts as in FIGS. 1 and 2 of the first embodiment are given the same reference numerals, and the explanation thereof will be omitted, and the parts different from the first embodiment will be mainly described.

The back surface of the housing 26 facing the photosensitive drum l of the main cartridge is formed into a substantially V-cut shape, and this V-cut 5
The portion is formed with a stepped portion 26B into which a part of the main body of the color developing device N3, which is a sub-cartridge, is engaged, and an opening portion 26c into which the developing sleeve 3A side of the one-color developing device 3 is inserted.

Reference numeral 60 denotes a cover member for opening and closing the opening 26c and shielding the inside of the housing from the outside, and has a substantially right-angled shielding plate 60a at its tip, and a shaft pin 61 (
(only one is shown in the drawings), the counterclockwise direction is rotatably pivoted near the opening 26c of the left and right side plates 27 of the housing 26, and the opening 26c is always closed by a spring member such as a torsion spring (not shown). At the same time, the left and right pivot bases are provided with a color developing device 3.
The bottom surface of the main body of the housing 2 is engaged with the cover member 60.
A cam 63 is provided to be rotatably housed within the cam 6. Moreover, in the cover member 60.

A slit-shaped beam entrance Bob is formed through which the laser beam Ll incident from the exposure hole 51 formed in the housing 26 passes.

In FIG. 7, 64 is a stay provided in the printer main body facing the back of the process cartridge A, and a pressure plate 6 is provided on the surface of this stay 64 facing the color developing device 13.
5 is attached via a pressure spring 66.

When the process cartridge A is installed in the printer main body, the pressure plate 65 is attached to the color developing device 3, which is a sub-cartridge.
The developing sleeve 3A of the color developing device 3 is moved into the photosensitive tram l by the spring force of the pressure spring 66.
The brown developing device 3 is stably held in the housing 26 of the main cartridge by contacting the developing device 3 with a predetermined pressure.

Next, the process of attaching and detaching the color developing device 3, which is a sub-cartridge of the process cartridge configured as described above, will be described.

First, process cartridge A is taken out of the printer body and placed on a stand such as a desk as shown in FIG. 6 in the same manner as in the first embodiment described above. Since the pressing force of the pressure plate 65 against the color developing device 3 is removed, the color developing device 3 is in contact with the photosensitive drum 1 due to its own weight.

Further, since the cam 63 of the cover member 60 is engaged with the bottom surface of the color developing device, the cover member 60 is held in the same state as shown in FIG. 5. At this time, the back side of the color developing device 3, which is a sub-cartridge, is exposed, so one operator can use the color developing device as it is! You can grab 3. In addition, since a part of the notch guide groove 46 for guiding the insertion of the sub-cartridge provided on the left and right side plates 27.27 of the main cartridge housing 25 is narrow, when the operator lifts the sub-cartridge, the guide pin When passing through the narrow part of the guide groove 43, the left and right side plates 27.2 encounter resistance.
Since the cartridge 7 is elastically deformed, the sub-cartridge can be taken out as it is.

During this process, the cover member 60 is biased counterclockwise by a spring member (not shown), so it automatically rotates in a direction to close the opening 26c and enters the state shown by the broken line in FIG. This closes the opening 26c from the inside and protects the inside of the process cartridge A with the cover member 60.

To set the sub-cartridge, simply follow the above-mentioned order. First, hold the sub-cartridge and insert it while aligning the guide pin 43 with the guide w446.

Insert until the guide pin 43 passes over the narrow click portion of the guide groove 46. At this time, since the sub-cartridge is not pressurized against the photosensitive drum l, it is moved in the attachment/detachment direction shown in FIG. 6 by the amount of play between the guide groove 46 and the guide pin 43. In order to lock the narrow part, the sub-cartridge does not fall out from the main cartridge during the operation of installing the cartridge A into the printer body, and the cover member 60
transitions to the fully open state as the sub-cartridge is inserted.

Therefore, according to this embodiment, it is very easy to attach and detach the sub-cartridge, and since the cover member 60 is attached inside the main cartridge and is configured to rotate inward, the cover member 60 is very easy to attach and detach. The subcartridge can be attached and detached without having to do so, and the photosensitive drum l can be reliably protected. Furthermore, by attaching the pressure mechanism for the sub-cartridge to the printer main body, it is possible to simplify the process cartridge A and reduce costs.

Figures 8 through 10 show a third embodiment of the process cartridge according to the present invention. FIG. 10 is a schematic cross-sectional view of the process cartridge of this embodiment applied to a laser beam printer.

In these figures, the same or equivalent parts as in the first and second embodiments are given the same reference numerals, and the explanation thereof will be omitted, and different parts will be mainly described.

As is clear from FIGS. 8 and 9, the opening 26A for inserting and removing the color developing device 3, which is a sub-cartridge, into and from the housing 26 of the main cartridge is opened and closed, and the photosensitive drum l facing the opening 26A is opened and closed. Both left and right ends of the base of the cover member 70 that protects the peripheral surface of the cover member 70 are opened and closed by shaft pins 33 (only one of which is shown) on a support portion 32 protruding from the partition wall 6B of the cleaning device 6 opposite thereto. A connecting piece 71 is bendably connected to the tip edge of the swinging side of the cover member 70.
A first Velcro tape 72a is fixed to the inner surface of the housing 26, and a second Velcro tape 72b is fixed to the side edge of the opening 26A of the housing 26 where the coupling piece 71 is overlapped. By joining to the tape 72b, the cover member 70 is held in a closed state. Further, 73 is a stopper provided protruding from the housing 26 on the pivot base side of the cover member 70, and when the cover member 70 is opened as shown in FIG. 9, the pivot base comes into contact with the stopper 73. This restricts further rotation of the cover 70 in the opening direction. Also,
The second charger 4 is integrally assembled with the color developing device 3, which is a sub-cartridge.

Process cartridge A configured as above is the first
0 [, when the cover member 70 is installed in the main body of the Busonto, the pressure plate 65 presses the cover member 70 in the direction of the photosensitive tram 1 by the spring force of the pressure spring 66. At this time, the connecting piece 7 joined to the housing 26 with the Velcro tape 72a.
1 is bent at its thin part 71a, so the cover member 7
o is rotated somewhat toward the inside of the process cartridge A around its shaft pin 33.

Therefore, the spring force of the pressure spring 66 is transmitted to the color developing device 3, which is a sub-cartridge, through the cover member 70, and presses the developing sleeve 3A against the circumferential surface of the photosensitive drum l.

In addition, when attaching and detaching the sub-cartridge, the operator peels off the Velcro tape 72a of the coupling piece 71 of the cover member 70 from the Velcro tape 72b, and attaches the cover member 70 to the ninth
Open it as shown in the figure.

The color developing device M3, which is a sub-cartridge, can be taken out from the main cartridge, and a new color developing device 3 can be inserted into and removed from the main cartridge. At this time, the opening angle of the cover member 70 is limited by the stopper 73,
Although it cannot be opened further than the state shown in FIG. 9, it is possible to attach and remove the sub-cartridge in this state, and the center of gravity of the cover member 70 is on the right side of the shaft pin 33 as shown in FIG. When the operator releases his/her hand from the cover member 70, the cover member 70 is automatically rotated in the closing direction due to its own weight, and the photosensitive drum is placed in the state shown by the two-dot chain line in FIG.
This protects the inside of the main cartridge, including the main cartridge.

Further, when the color developing device 13, which is a sub-cartridge, is replaced with a new one, the second charger 4 is also replaced at the same time, which has the effect of always being able to perform stable and reliable charging.

In the above embodiment, two developing devices are provided in the process cartridge, and the color developing device 3 is replaced. However, it is also possible to replace one or more of the two or more developing devices. Of course, the shutter method of the present invention can also be applied to process cartridges that can be used.

Furthermore, the process cartridge of the present invention can be used not only for printers but also for other electrostatic recording type image forming apparatuses.

(Effects of the Invention) As described above, according to the present invention, there is provided a process cartridge having a main cartridge that can be attached to and detached from the main body of an image forming apparatus, and a sub-cartridge that is detachable from the main cartridge and has at least a developing means. , since the main cartridge is provided with a movable cover member that covers the sub-cartridge insertion portion of the main cartridge and blocks the inside from the outside when the sub-cartridge is not inserted into the main cartridge;
Even if the sub-cartridge is removed from the main cartridge when replacing the developing means, damage to the inside of the main cartridge including the latent image carrier (photosensitive drum) and foreign objects from the outside may occur.
The cover member can prevent dust from entering, and this has the effect of facilitating the handling of the process cartridge and the replacement of the sub-cartridge.

[Brief explanation of the drawing]

FIG. 1 is an overall sectional view showing a first embodiment of a process cartridge according to the present invention, FIG. 2 is a side view showing a state in which a sub-cartridge is attached to and removed from a main cartridge in the first embodiment, and FIG. FIG. 3 is a schematic cross-sectional view of the entire process cartridge of the embodiment when it is installed in a laser beam printer. FIG. 4 is a schematic cross-sectional view of a laser beam printer equipped with the process cartridge of the first embodiment, with the front panel opened, and FIG.
FIG. 6 is a side view showing how the sub-cartridge is attached to and removed from the main cartridge in the second embodiment. FIG. 7 is a schematic cross-section of a laser beam printer equipped with the process cartridge of the second embodiment. 8 is a cross-sectional view showing the third embodiment of the process cartridge according to the present invention, FIG. 9 is a side view showing the state of attachment and detachment of the sub-cartridge to the main cartridge in the third embodiment, and FIG. FIG. 11 is a schematic sectional view of a laser beam printer equipped with a process cartridge according to an embodiment, and FIG. 11 is a schematic configuration diagram showing an example of a two-color printer. A... Process cartridge, 1-... Photosensitive drum (
latent image carrier), 2--first charger, 3--color developing device as a sub-cartridge, 4--second charger. 5... A silent image device, 6-... Cleaning device, 26
...Heading, 26A, 27B-...Opening, 31
゜60.70--Cover part, 33.61--Axle pin. Patent Applicant Canon Co., Ltd. Agent Patent Attorney Ryo Yamashita - Figure 1 Figure 2 Figure 6

Claims (2)

[Claims] (1) A main cartridge that contains a latent image carrier, a developing means, and other image forming process equipment and is removable from the main body of the image forming apparatus, and a subcartridge that is removable from the main cartridge and has at least a developing means. In the process cartridge, when the sub-cartridge is not attached to the main cartridge,
A process cartridge characterized in that a cover member that covers a sub-cartridge mounting portion of the main cartridge and blocks the inside of the cartridge from the outside is biased in one direction to cover the sub-cartridge. (2) An image forming apparatus comprising the process cartridge according to claim 1 removably loaded into a main body.