JPH03260663A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent developer from dropping at the time of loading/unloading an image producing cartridge by closing a space between an image carrier and a developing device in a state where the image producing cartridge is not loaded and retreating a closing member by interlocking with the loading action of the image producing cartridge. CONSTITUTION:When the image producing cartridge 1 is not loaded, the space between the photosensitive drum 4 and the developing roller 11 is closed by the closing member 44. A rocking lever 45 is rocked in a direction shown by an arrow with the loading of the cartridge 1, and the member 44 is retreated in the retreat recessed part 3a of a waste toner casing 3. By pulling out the cartridge 1, the lever 45 is rocked by a torsion spring 47 and the space between the photosensitive drum 4 and the roller 11 is perfectly closed by the member 44. Thus, a device main body and the peripheral part thereof are prevented from being contaminated by the developer leaked out in the case of loading/ unloading the cartridge 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, or a printer that forms an image by an electrophotographic method, and particularly relates to an image forming apparatus that forms an image using an electrophotographic method, such as a copying machine, a facsimile machine, or a printer. The present invention relates to an image forming apparatus in which a combination of image forming cartridges is removably attached to an apparatus main body.

BACKGROUND ART This type of image forming apparatus is disclosed in Japanese Patent Application Laid-Open No. 5715425, for example.
This method is known from Japanese Patent Publication No. 5 and Japanese Patent Application Laid-Open No. 61-279872. In the image forming apparatuses disclosed in these publications, in order to easily replace consumables such as the image carrier, an image carrier, a developing means for developing a latent image, and a An image forming cartridge is used in which at least three of the three waste toner removing means for removing residual toner are integrally combined, and more preferably a charger is integrated.

Furthermore, in Japanese Patent Application Laid-Open No. 63-235970, a leak prevention sheet that lightly slides on the surface of the developing means is provided, and a container-shaped spill prevention member is further provided at the bottom of the developing means on the side of the image carrier from the leak prevention sheet. What has been placed is disclosed.

Problems to be Solved by the Invention Incidentally, in an image forming cartridge, an opening is provided at least in the image carrier portion in order to allow the image carrier to face the paper passing path provided on the apparatus main body side. There is a problem in that when the image forming cartridge is attached to and removed from the apparatus main body, the developer may spill downward from between the image carrier and the developing means, contaminating the inside and surroundings of the apparatus main body.

On the other hand, if a leak prevention sheet and a spill prevention member are provided as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 63-235970, it is possible to almost eliminate developer spillage. There is a problem in that the developer may spill when the printer is installed at an angle or when it is tilted during handling.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can prevent developer from spilling into undesirable areas when an image forming cartridge is attached or removed.

Means for Solving the Problems In order to achieve the above-mentioned problems, the present invention provides an image forming cartridge which integrally combines an image bearing member and at least a developing means, and is removably attached to an apparatus main body. In the forming apparatus, a closing member is provided for closing a space open to the outside between the image carrier and the developing means, and this closing member is linked to the mounting operation of the image forming cartridge or the subsequent positioning operation to the image forming position. This feature is characterized by the provision of interlocking means for moving to the retracted position.

Function In the above structure of the present invention, when the image forming cartridge is taken out from the main body of the apparatus, the space open to the outside between the image carrier and the developing means is closed by the closing member, so that the image forming cartridge is removed from the apparatus main body. There is no risk of the developer spilling out during attachment/detachment or after removal. On the other hand, image forming car) I
When the J-judge is mounted on the apparatus main body and positioned at the image forming position, the closing member moves to the retracted position in conjunction with the mounting or positioning operation, so that there is no problem with the image forming operation.

EXAMPLE An example in which the present invention is applied to a printer will be described below with reference to FIGS. 1 to 7.

First, the basic structure of the image forming cartridge 1, which is a main part of the printer, will be explained based on FIG. In FIG. 3, the image forming cartridge 1 is formed by connecting a developer casing 2 and a waste toner casing 3 as shown in the figure. A photosensitive drum 4 is provided at the connecting end of the waste toner casing 3 and is pivotally supported on the side wall of the waste toner casing 3 by a shaft 6. A cleaning blade 7 is brought into pressure contact with the back of the photosensitive drum 4, and residual toner scraped off from the top of the photosensitive drum 4 is stored in the waste toner casing 3. To accommodate this, a paddle 8 is provided near the bottom of the waste toner casing 3 behind the photosensitive drum 4 to scrape the toner scraped from the photosensitive drum 4 into the waste toner casing 3. The photosensitive drum 4 has a photoconductive layer made of zinc oxide, selenium, organic photoconductive material, etc. formed on the surface of a metal base such as aluminum, and forms an electrostatic latent image by imagewise exposure.

A developing roller 11 for developing the electrostatic latent image on the photosensitive drum 4 with toner is provided at the connecting end of the developing device gauging 2, and is pivotally supported on the side wall by a shaft 12. A sponge roller 13 is provided on the back of the developing roller 11 and is pivotally supported on the side wall of the developing device casing 2 by a shaft 14, which charges the developer and supplies it to the developing roller 11. A developer supply paddle 15 is provided inside the developer casing 2 and is pivotally supported on a side wall by a shaft 16 for stirring the developer in the developer casing 2 while supplying it to the sponge roller 13 . The shaft 16 is equipped with stirring blades 17 to prevent toner from forming into blocks.
is installed.

A wire 82 for scraping off the developer is provided on the back of the sponge roller 13. This wire 82 is stretched between the opening edges of a partition plate 95 in the developer casing 2 and is pressed against the back surface of the sponge roller 13. As a result, when the residual developer that has been supplied to the developing roller 11 on the sponge roller 13 returns to the back side of the sponge roller 13, this residual developer is scraped off from the surface of the sponge roller 13 by the wire 82. , and returned to the unused developer. Therefore, the residual developer that remains after being supplied to the developing roller 11 does not leave the surface of the developing roller 11 and is repeatedly supplied to the developing roller 11 as it is, or is scraped off once from the surface of the developing roller 11. This prevents the developer from being captured by the sponge roller 13 and supplied to the developing roller 11 without being mixed with unused developer. For this reason, the sponge roller 13
It is possible to prevent the stress of the residual developer that was not supplied to the developing roller 11 from affecting the developing characteristics.

The developer casing 2 and the waste toner casing 3 are connected to the shaft 2.
Positioning rollers 23 and 24 provided on the shafts 6 and 12 of both the photosensitive drum 4 and the developing roller 11 are connected to each other so as to be swingable by the shafts 6 and 1 of the photosensitive drum 4 and the developing roller 11.
They are brought into pressure contact with each other, and a predetermined gap is maintained between the photosensitive drum 4 and the developing roller 11 while absorbing manufacturing and assembly errors of each part.

A lid 30 is attached to an upwardly opened developer input port 83 of the developer casing 2, and is fixed to the developer casing 2 by an appropriate method such as adhesion, welding, or screwing. The lid 30 extends to the waste toner casing 30 and covers the waste toner casing 3, making it easy to handle the image forming cartridge 1 as an integral part. Especially I
t30 is heavier than the waste toner casing 3 and is fixed to the side of the larger developer casing 2 to form the gripping portion H for integral handling, so that the stability of the image forming cartridge 1 during handling is improved. It becomes even easier to handle. Note that a play is provided between the lid 30 and the waste toner casing 3 to an extent that does not impede the necessary rocking of the waste toner casing 3 relative to the developer casing 2 due to pressure contact between the positioning rollers 23 and 24.

Further, a sealing plate 25 is provided at the bottom of the connecting end opening of the developer casing 2 and extends to the circumferential surface of the developing roller 11 and comes into pressure contact therewith. A seal plate 26 is provided that extends to the drum 4 and presses against it. As a result, the developer handling space of the image forming cartridge 1 formed by the developer casing 2 and the waste toner casing 3 becomes almost sealed, thereby preventing the developer from scattering to the outside. I can do it.

Furthermore, a shallow container-shaped spill prevention portion 27 is provided at the bottom of the connecting end opening of the developer casing 2 so as to cover the space below the developing roller 11 on the rear side in the rotational direction of the developing roller 11 than the seal plate 25 . A plurality of ribs 28 are arranged in parallel in the rotational direction of the developing roller 11 on the inner bottom surface thereof and extending to a position facing the outer peripheral surface of the developing roller 11 with a small gap therebetween. As a result, the developer that falls off the outer circumferential surface of the developing roller 11 before reaching the seal plate 25 or while passing through the seal plate 25 falls into the spill prevention part 27 and is collected. The agent is multiple replies 28
Since it does not leak outside unless it passes through the narrow gap between the upper end and the outer peripheral surface of the developing roller 11, it hardly leaks outside. Thus, even if the spill prevention section 27 is formed into a shallow container shape, the developer will not spill out, and it can be placed in the narrow space between the developing roller 11 and the paper passing bus 37 without any problem.

Furthermore, as shown in FIG. 1, the image forming cartridge 1 has an opening to the outside between the end surface of the spill prevention section 27 at the connecting end of the developer casing 2 and the outer circumferential surface of the photosensitive drum 4 facing thereto. A closing member 44 is provided that fits into and closes the space. This closing member 44 is attached to be able to swing slightly between one end 45a of a swing lever 45 that is swingable around a shaft 46 provided on both sides of the waste toner casing 3. The closing member 44 is biased to swing by a torsion spring 47 so as to fit into the space. The other end 45b of the swinging lever 45 passes through a slit 48 formed in the cover 30 and projects upward, and by swinging the other end 45b of the swinging lever 45 in the direction of the arrow against the torsion spring 47. Closing member 44
is the evacuation recess 3 formed on the bottom surface of the waste toner casing 3.
It is configured to retreat into a. Further, pads 49a and 49b are attached to the contact surfaces of the closing member 44 with respect to the photosensitive drum 4 and the spill prevention member 27, and pads 49a and 49b are attached to the lower surface of the closing member 44 so as to protrude downward from the lower end of the photosensitive drum 4. A protruding member 50 is attached to protect the.

This image forming cartridge 1 is used by being attached to a printer 31 as shown in FIG. In this printer 31, an upper frame 33 can be opened and closed vertically about a hinge shaft 34 with respect to a lower frame 32, and the image forming cartridge 1 is installed in the upper frame 33 as shown by the outline arrow in FIG. . This attachment is performed detachably from the rear of the upper frame 33 that opens upwardly along guides (not shown) provided inside both side walls of the upper frame 33. When the image forming cartridge 1 is installed, the other end 45b of the swing lever 45 engages with the engagement protrusion 40 provided at a predetermined position on the upper frame 33, and as the image forming cartridge 1 is installed, the swing lever 45
5 is swung in the direction of the arrow, and the closing member 44 is retracted into the retraction recess 3a of the waste toner casing 3. At that time, the closing member 4 leaks slightly from the open end of the developer casing 2.
When the closing member 44 moves toward the retreat recess 3a and stops abruptly, the developer adhering to the fixing section 4 drops downward. Since it falls onto the case, it does not fall onto the paper passing bus 37 or other places where it would be a problem if the developer adhered.

Thereafter, by closing the upper frame 33 with respect to the lower frame 32, the imaging cartridge 1 is moved to the lower frame 32.
A paper passing path 37 for printing is formed between the transfer charger 36 provided on the second side and the transfer charger 36 provided on the second side. On the other hand, when the upper frame 33 is opened upward as shown in FIG.
7 can be opened to easily troubleshoot problems such as jams.

Further, when the image forming cartridge 1 is pulled out upward, the swing lever 45 is swung by the torsion spring 47, and the space between the photosensitive drum 4 and the spill prevention member 27 is closed as shown by the solid line in FIG. is completely closed by the closing member 44, and leakage of the developer is completely prevented. Therefore, even if the image forming cartridge 1 is handled somewhat roughly when being pulled out diagonally upward, the developer will not leak out and fall downward, contaminating the inside of the main body of the apparatus or the surrounding area.

A laser scanning unit 38 is provided above the portion of the upper frame 33 where the image forming cartridge 1 is mounted. This laser scanning unit 38 deflects a laser beam 39 from a laser emission source modulated according to an image signal provided by a personal computer, image league, etc., onto the photosensitive drum 4 using an appropriate scanning means such as a polygon mirror. image exposure on the photosensitive drum 4. For this image exposure, the image forming cartridge 1 has an I
An exposure slit 51 that enables image exposure to the photosensitive drum 4 is provided in a part of the E30, and the image forming cartridge 1
Inside, an electrostatic latent image is formed by image exposure.
A charger 52 that uniformly charges the surface of the photosensitive drum 4 is provided in front of the image exposure position of the photosensitive drum 4.

However, due to recent miniaturization and weight reduction, the thickness of each member forming the image forming cartridge 1 tends to become thinner and the rigidity tends to decrease. Therefore, when handling the image forming cartridge 1 alone, an external force for gripping the image forming cartridge 1 acts on the developing device casing 2 forming the grip part H of the image forming cartridge L, causing temporary deformation such as twisting or denting. It may also occur. At this time, the volume of the developer casing 2 may momentarily decrease, and the developer may be blown out along with the internal air from the weak portion of the seal.

Therefore, in this embodiment, an opening 84 is formed in the lid 3o, which is closed with a semipermeable membrane 85. The semipermeable membrane 85 is one that allows air to pass through but does not allow the developer to pass through. As a result, even if the developer casing 2 is deformed as described above during handling of the image forming cartridge 1 and the volume is reduced and internal air is blown out, the semi-permeable membrane 85 with less resistance prevents the air from blowing out. Even if the developer tries to get onto the blown air, the semi-permeable membrane 8
5 to prevent it from spewing out to the outside. Such a structure can be applied to the waste toner casing 3 as well, if necessary.

Note that the sealing performance can be further improved by providing the seal plates 25 and 26 in the developer casing 2 and the waste toner casing 3 in multiple stages as necessary, and pressing them against the surfaces of the developing roller 11 and the photosensitive drum 4 in multiple stages in their rotational directions. improves.

As shown in detail in FIGS. 5 and 6, an elastic blade 41 is pressed against the developing roller 11. As shown in FIGS. As the elastic blade 41, a rubber blade made of urethane rubber, silicone rubber, or the like, or a metal blade made of spring-use phosphor bronze, spring steel, or the like is useful. The upper end of the elastic blade 41 is attached by adhesive or the like to a metal support member 42 that is stretched between the side walls of the developer casing 2, and the lower end is pressed against the surface of the developing roller 11.

Incidentally, the developing roller 11 has a developer carrying area X on the central side in the longitudinal direction formed with a satin surface by sandblasting or the like, which is advantageous for carrying the developer. Both ends of the developing roller 11 on both sides of the developer carrying area be. For this reason, the developer non-carrying area Y is kept as a smooth surface to avoid carrying the developer.

As a result, the developer carrying area X of the developing roller 11 has a satin-like unevenness formed on its surface, and the convex portion rises from the surface of the fabric, so that the diameter thereof is slightly increased compared to the developer non-carrying area Y. In addition, since the developer carrying area X of the developing roller 11 carries the developer supplied from the sponge roller 13, although the developer is thinned to a predetermined layer thickness by pressure contact with the elastic blade 41, the developing roller The diameter of the developer carrying area X portion of No. 11 is further increased. Therefore, the diameter of the developer carrying area X of the developing roller 11 is somewhat different from that of the developer non-carrying area Y, and there is a gap between the developer carrying area X and the developer non-carrying area Y of the developing roller 11. Step Z
(Figure 6) will occur.

Therefore, if the elastic blade 41 is uniformly and continuously pressed over the entire length of the developing roller 11, it will not carry the developer, and moreover, the developer non-carrying area Y will have a small diameter.
Floating occurs between the two and causes the developer to leak forward.

In order to solve this problem, in this embodiment, a notch 86 cut from the tip is formed in the portion of the elastic blade 41 facing the boundary K between the developer carrying area X and the developer non-carrying area Y of the developing roller 11. is forming. As a result, the elastic blade 41 is divided by the notch 86 into the center side in the longitudinal direction, which faces the developer carrying area Since the respective portions 41a and 41b independently press against the developer carrying area X and the developer non-carrying area Y of the developing roller 11 without being influenced by each other, there is a step Z between the respective areas X and Y. Even elastic blade 410 part 4
The elastic blade 1b can be brought into close contact with the developer non-carrying area Y, as shown in FIG. 6, regardless of the part 41a of the elastic blade that is pushed away by the developer in the developer carrying area X. Therefore, the elastic blade 41
It is possible to eliminate the problem of the developer floating from the developing roller 11 in the developer non-carrying area Y and causing the developer to leak from the developer non-carrying area Y to the photosensitive drum 4tIlj.

Further, the portion 41b of the elastic blade 41 is attached to the support member 42.
It is held down by presser metals 57 attached to both ends of the holder, which further prevents it from lifting up. Developing roller 1
A sealing material 88 is interposed between 1 and the side wall 87.

Furthermore, in a long continuous portion of the elastic blade 41 in the longitudinal direction, pressure contact with the developing roller 11 tends to be stronger in the central portion of the continuous range than in other portions.
The layer thickness of the developer formed on the developing roller 11 tends to be non-uniform in the axial direction of the developing roller 11, which causes uneven development characteristics. Therefore, in this embodiment, in order to solve this problem,
A groove 81 as shown in FIGS. 3 and 5 is formed on the back surface of the elastic blade 41. This groove 81 is located approximately at the center in the width direction of the elastic blade 41, and is formed in a range excluding both ends of the portion 41a between the long cuts 86 of the elastic blade 41.

This allows the long portion 41a of the elastic blade 41 to
The bending rigidity at the central portion in the longitudinal direction is weakened by the concave groove 81, the pressing force against the developing roller 11 is reduced, and the pressing force against the developing roller 11 of the entire long portion 41a of the elastic blade 41 is reduced. become even.

Furthermore, stress is concentrated in the concave groove 81 portion of the elastic blade 41, and by equalizing the stress in other portions, the pressing force against the developing roller 11 can be made uniform.

Therefore, a thin layer of developer can be formed with a uniform layer thickness over the entire developer carrying area X of the developing roller 11, and uniform development characteristics can be expected over the entire developer carrying area X of the developing roller 11.

In addition, the elastic blade 41 is made of polyethylene terephthalate (
If it is formed by punching from a sheet such as PET, the cost will be lower than when a molded product such as urethane foam is used. In this case PET
Since it is made of a strong material, it does not damage the developing roller 11 or cause chattering, and it is preferable to press the developing roller 11 at the so-called abdomen in order to avoid contact with the tip edge.

Furthermore, since the elastic blade 41 is made of an insulating material, the frictional charging between the developer and the elastic blade 41 can be increased, and the overall charging state can be sufficiently stabilized. In this sense, forming a coating layer of an insulating material on the surface of the developing roller 11 can further improve the charging characteristics. Furthermore, since the insulating coating layer can form a matte surface during resin molding without sandblasting, the cost of the developing roller 11 is reduced accordingly, and the developer can be transported to areas where the electric field is not diffused. At the same time, since the gap between the developing roller 11 and the photosensitive drum 4 can be shortened beyond the discharge limit, the resolution in development is improved.

As another example, an insulating elastic roller may be used instead of the elastic blade 41, in which case the developing roller 11
You can set the relative speed in any way you like. This allows the charging characteristics to be adjusted in various ways,
Depending on whether the elastic roller is rotated in a subordinate direction to the developing roller 11 or in the opposite direction, the surface layer of the developer on the developing roller 11 is actively subjected to development;
It becomes possible to select whether to make it difficult to be subjected to development. Such selection is based on the developer, developer supply mechanism, and photosensitive drum 4.
This is useful when dealing with various types of image forming conditions, such as types, etc., or when responding to special requests.

In addition, a speed change mechanism is provided in the drive system of the developing roller 11 to increase the rotational speed of the developing roller 11 when forming an image with poor reproducibility such as a line drawing or a dot image. Increasing the supply amount improves reproducibility even for line drawings and dot drawings.

In this embodiment, the configuration of the charger 52 is devised in response to the fact that the photosensitive drum 4 is designed to have an extremely small diameter. The photosensitive drum 4, which has an extremely small diameter, faces the charging charger 52 on a curved surface with a sharp degree of curvature, and it is difficult to perform stable charging due to the influence of higher speeds. Therefore, the charger 52 connects the mesh of the grid section 53 to the photosensitive drum 4.
It is arranged so that it gradually becomes finer from the upstream side to the downstream side in the direction of rotation (Figures 3 and 4). As a result, the charging charger 52 is initially a corotron type charger without a grid or exhibiting charging characteristics similar to that to ensure charging performance for the rotating photosensitive drum 4, and then a scorotron type charger with a grid. This ensures good controllability of charging by exhibiting excellent band shape retention.

This makes it possible to achieve stable charging by ensuring both charging performance and charging controllability.

Although the charger 52 is formed into one for miniaturization, it is also possible to install two chargers, a corotron type charger and a scorotron type charger. Further, the size of the mesh may change continuously or discontinuously. The charger 52 has a grid portion 53 for miniaturization.
and a discharge stabilizing frame 54 are integrally formed from a metal plate. The corona wire 55 is installed between resin blocks 56 attached to both side walls of the developer casing 2.
This resin block 56 holds the end of the discharge stabilizing frame 54.

Note that the corona wire 55 has a wire diameter of about 80 μm, which is extremely thin, so there is a problem with elongation and cutting, which makes it troublesome to handle during installation, and maintenance such as cleaning when it becomes dirty due to use is also troublesome. Therefore, it is conceivable that a metal plate is buried in a resin base (not shown) by insert molding or the like, and a part of the buried metal plate is exposed to be used in place of the corona wire. In this case, costs can be reduced and the strength of the corona electrode portion is improved, making assembly and cleaning easier. Alternatively, a predetermined metal material may be printed in a line shape on the surface of the resin base to serve as a substitute for the corona wire. In this case as well, the same effects as the above improvements can be expected.

Further, the discharge stabilizing frame 54 can also be formed by applying metal plating to the inner surface of the resin housing. In this case, the resin housing can be integrally formed with a part of the existing member such as the lid 30, and the structure can be simplified.

The transfer roller 36 has an upper frame 33 and a lower frame 32.
When it is closed upward, it is disposed so as to face the photosensitive drum 4 of the image forming cartridge 1 with a certain gap therebetween.

A timing roller pair 61 is provided in front of the transfer section of the paper passing bus 37, as shown in FIG. The timing roller pair 61 temporarily stops receiving the transfer paper 91 picked up and fed from the paper feed cassette 92 by the pickup roller 93 in a stopped state, and thereafter feeds the transfer paper 91 at a predetermined timing, and then feeds the transfer paper 91 to the photosensitive drum. The leading edge is aligned with the toner image formed on 4 and used for transfer.

A pair of fixing rollers 62 is provided behind the transfer section, and heat fixes the transfer sheet fed after the transfer.

The surface of the photosensitive drum 4 after the transfer is cleaned by a cleaning blade 7 to remove residual toner.

An eraser lamp 63 is provided immediately after the transfer charger 36 of the lower frame 32, and irradiates erase light onto the surface of the photosensitive drum 4 after transfer through the transfer paper 91 that is being passed, thereby eliminating any residue on the surface of the photosensitive drum 4. Removes charge. Near this eraser lamp 63, a light receiving end 65a of an optical fiber 65 is provided.
is positioned facing the photosensitive drum 4. The optical fiber 65 guides reflected light when the toner image formed on the photosensitive drum 4 is illuminated by the eraser lamp 63 to a density sensor 64 provided at an appropriate position. As a result, the concentration sensor 64 is activated by the eraser lamp 6.
3 for illuminating the image to be inspected, and by using the eraser lamp 63 in common and using the optical fiber 65, the toner image can be detected without requiring any special space around the transfer section. The concentration can be detected, and the cost can be reduced because the eraser lamp 63 is shared.

By sending the detected density of the toner image to the control system, it is possible to determine the state of developer shortage or deterioration, and to take measures such as a warning of the limit of use due to the lifespan of the image forming cartridge l, or to stop printing.

Note that if the eraser lamp 63 is installed within the discharge stabilizing frame of the transfer charger 36, further space saving can be achieved.

Furthermore, the cleaning blade 7 can be formed of a transparent resin material and used as a light guide to irradiate the surface of the photosensitive drum 4 with eraser light. According to such an erase method, the degree of freedom in selecting the installation location of the eraser lamp 63 increases. Furthermore, cleaning blade 7
Similarly to the elastic blade 41, a concave groove can be formed on the back of the blade to equalize the pressing force. In this case, the resonant frequency of the blade can be easily selected.

Furthermore, the cost can be reduced by punching out a PET sheet, and the waste toner casing 3 is provided with an unused detection mechanism 71 linked to the drive system, as shown in FIG. . This unused detection mechanism 71 is a gear 73 provided on one shaft of the drive system, for example, the rotating shaft 72 of the paddle 8 for scraping in waste toner.
The detection gear 74 is engaged. The detection gear 74 has teeth 75 only on a part of the outer periphery, and the other part of the outer periphery is a cam surface 77 having a recess 76 in a part. The waste toner casing 3 also includes a detection pin 78 facing the cam surface 77.
is held movably forward and backward, and this detection pin 78 is brought into contact with the cam surface 77 by a spring 79. When the image forming cartridge 1 is not in use, that is, when the drive system has never been operated and no developer is consumed, this abutment position is set a predetermined amount downstream from the recess 76 of the cam surface 77 in the driving direction. It is a remote location.

When the image forming cartridge 1 is installed in the printer 31 and is driven and used even once, the gear 7 that is interlocked with the drive is activated.
3 rotates the detection gear 74. The concave portion 76 of the cam surface 77 faces the detection pin 78 by an amount of rotation that is extremely small compared to the amount of drive required for use. At this opposing position, the detection pin 78 is fitted into the recess 76 by the force of the spring 79.

The detection pin 78 protrudes outside the waste toner casing 3 when the image forming cartridge 1 is not in use, and when the image forming cartridge 1 is mounted on the upper frame 33, the switch 94 provided on the upper frame 33 is activated. It is pushed by the detection pin 78 and automatically detects that the image forming cartridge 1 is unused. This detection signal is sent to the control system of the printer 31 to start counting the number of prints using the image forming cartridge 1 and to issue a restriction or warning against use of more than a predetermined number of prints based on this count. Conversely, if the image forming cartridge 1 to be installed has already been used, the detection pin 78 is retracted toward the waste toner casing 3, so even if the image forming cartridge 1 is installed in the upper frame 33, Switch 94 cannot be pressed. Therefore, no action is taken as would be the case when the unused waste toner casing 3 is attached.

However, the usage status can also be detected at the necessary time. For example, by detecting the point in time when a predetermined number of sheets, such as 500 sheets, have been used and using this as a use start signal, it is possible to support test use of up to 500 sheets. Furthermore, it can be said that the point in time when the image forming cartridge 1 has been used for printing the maximum number of sheets for use is detected and a warning is given for further use.

In the above embodiment, the closing member 44 is attached to one end 45a of the swing lever 45, but as shown in FIG.
A shutter-like closing member 96 may be attached to the outer circumferential surface of the photosensitive drum 4 so as to be movable toward and away from the outer peripheral surface of the photosensitive drum 4 , and may be biased to protrude toward the photosensitive drum 4 by a compression spring 97 . A pad 98 that comes into contact with the outer peripheral surface of the photosensitive drum 4 is attached to the tip of the closing member 96 . Further, a mounting portion of the image forming cartridge 1 in the upper casing 33 is provided with a closing member 96 such that when the image forming cartridge 1 is mounted on the upper frame 33, the closing member 96 moves to a retracted position where it is retracted toward the developer casing 2 side. Protrusions (not shown) that engage with engaged protrusions (not shown) provided on both sides of the closing member 96 are appropriately provided.

Furthermore, in the embodiments described above, the closing member 44 or 96 is moved to the retracted position when the image forming cartridge 1 is mounted on the upper frame 33, but the upper frame 33 is closed on the lower frame 32 and the image forming cartridge l The closing member 44 or 96 may be moved to the retracted position using a cam mechanism or the like as appropriate in conjunction with the positioning of the printer at a predetermined printing operation position.

Effects of the Invention According to the present invention, when the image forming cartridge is taken out from the apparatus main body, the space open to the outside between the image bearing member and the developing means is closed by the closing member, so that the image forming cartridge is removed from the apparatus main body. It is possible to reliably prevent the developer from spilling out when installing and removing the cartridge, and when the image forming cartridge is installed in the main body of the apparatus and positioned at the image forming position, it can be installed or removed without operator's operation. Since the closing member moves to the retracted position in conjunction with the positioning operation, there is an effect that the image forming operation is not hindered.

[Brief explanation of drawings]

FIG. 1 is a partial sectional front view of an image forming cartridge in a printer according to an embodiment of the present invention, FIG.
The figure is a sectional view of the image forming cartridge and the transfer charger section, FIG. 4 is a partially enlarged sectional view of the charging charger, FIG. 5 is a perspective view of the developing roller section, and FIG. 6 is an enlarged partially of the developing roller section. 7 is a sectional view of a part of the waste toner casing showing the unused detection mechanism of the image forming cartridge, and FIG. 8 is a partially sectional front view of the image forming cartridge in another embodiment of the present invention. . ■ 1 4 5 6 ・--・-・Image-forming cartridge・-・-・-・Photosensitive drum・-Developing roller closing member Swinging lever closing member

Claims (1)

[Scope of Claims] In an image forming apparatus in which an image forming cartridge in which an image bearing member and at least a developing means are integrally combined is removably attached to the main body of the apparatus, an external part between the image bearing member and the developing means is provided. A closing member for closing the open space is provided, and an interlocking means is provided for moving the closing member to the retracted position in conjunction with the mounting operation of the image forming cartridge or the subsequent positioning operation to the image forming position. Image forming device.