JPH03185464A - Process cartridge - Google Patents

Abstract

PURPOSE:To prevent the occurrence of an optical memory in the case of storage and to stabilize triboelectrification by providing a solar battery and a photosensitive drum rotating means and/or a developer stirring means driven by the battery. CONSTITUTION:By detaching a process cartridge 230 from an image forming device, a gear 281 and a gear 282 mesh with each other. Then, a motor is rotated by power from the solar battery 201, a photosensitive drum is rotated through a deceleration means and the gears 281 and 282, and a developing sleeve and/or a stirring and conveying screw rotates with the rotation of the drum. By rotating the photosensitive drum, the optical memory caused by leakage light is prevented from occurring even when a light shielding shutter, etc., is omitted. Owing to the rotation of the sleeve and the screw, the melting of binder resin is eliminated and blocking is prevented. Furthermore, the triboelectrification is stabilized from the initial time when the cartridge is used again.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention comprises a photosensitive drum, at least one process means such as a charging device, a developing device, a transfer device, and a cleaning device used to form an image on the photosensitive drum, and the photosensitive drum and the process means are integrally configured. The present invention relates to a process cartridge for an electrophotographic image forming apparatus that is detachable from a main body.

[Prior art]

Electrophotography generally uses a photoconductive substance as a photoconductor, charges the photoconductor surface by corona discharge, etc., neutralizes the charge on the photoconductor surface by image exposure, and forms an electrostatic latent image on the photoconductor. Then, the latent image is developed using colored fine powder called toner that is charged oppositely to the charge on the surface of the photoreceptor, and if necessary, the toner image is transferred to a transfer material such as paper, and then fixed by heat or pressure. It is for obtaining a copy. Conventionally, process means including a photoreceptor, etc., which deteriorates depending on the amount of use and has a limited durability, are made into cartridges and configured to be detachable from the main unit, making it easy to replace consumables. is considered. Examples of replacing consumables with cartridges include developing devices that reach the limit of their use due to toner consumption at the same time as photoconductor replacement, cleaning devices that accumulate used toner, and even discharge problems that occur due to toner adhesion. It is also effective to replace an easy-to-use corona charger or the like at the same time as the photoreceptor. As mentioned above, a structure in which consumables that need to be replaced due to use can be attached to and detached from the main unit is referred to as a process cartridge.The process means of such a process cartridge include a photoreceptor, a developing device, and a cleaning device. There are combinations of containers, corona chargers, etc. An image forming method using such a process cartridge is typically performed using the following apparatus and steps. FIG. 3 is a sectional view showing the configuration of an image forming apparatus using a process cartridge. In Figure 3, 3 old is a manuscript table made of a transparent member.
It reciprocates in the direction of the arrow. 302 is an imaging element array;
A light image of the document image on the document table is exposed onto the photosensitive drum 303 through slits 327 and 427 (FIG. 4). Note that the photosensitive drum rotates in the direction of the arrow. 304 is a corona charger that uniformly charges the photosensitive drum;
Reference numeral 5 denotes a developing device, which develops an electrostatic image formed by exposing a negatively charged photosensitive drum to light using an imaging element array 302 with toner. On the other hand, the transfer sheet P is fed onto the surface of the photosensitive drum 303 by a paper feed roller 306 and a register roller 307.
The toner image on the photosensitive drum is transferred by the transfer charger 308 . Thereafter, the transfer sheet P is separated by the separating means 313
The fuser 31 is separated from the photosensitive drum by a roller 321 that passes over a guide 309 and is located at the end of the conveyance path.
Sent to 0. The toner image on the transfer sheet is fixed by the fixing device 310, and the sheet is transferred to the tray 3 by the ejection roller 311.
12. On the other hand, toner remaining on the photosensitive drum without being transferred is scraped off by a cleaning blade and collected by a cleaning device 314. Furthermore, 31
5 is an illumination system for exposing the original, and 316 is a filter such as a heat ray absorption filter. Further, in FIGS. 3 and 4, image forming means such as a developing device 305, a cleaning device 314, and a charger 304 arranged around the photosensitive drum are integrated into light-shielding walls 330 and 4.
30 to form a process cartridge, and when the photosensitive drum is replaced, each unit in the cartridge is replaced at the same time, thereby reducing maintenance work. Furthermore, if the process cartridge can be easily replaced, multiple monochrome process cartridges can be used in addition to the black toner process cartridge for monochrome copying that uses color toner in addition to black toner. This can be done by preparing and replacing the process cartridges of each color as necessary. In this way, the manner in which the process cartridge is used and its management are left to the user who purchased the process cartridge. This can lead to situations where the process cartridge is used under unfavorable conditions or stored in insufficient conditions. Therefore, the photosensitive drum, toner, and other Materials and cartridge construction must be selected. For example, if a photosensitive drum is exposed to direct sunlight or fluorescent light for a long period of time, the photosensitive drum will deteriorate and optical memory will occur. When an image is formed using such a photosensitive drum, the density of the image becomes non-uniform between the area where the optical memory has occurred and the other areas. Therefore, in conventional process cartridges, the photosensitive drum and process means are surrounded by a light-shielding wall, and a movable shutter is provided in the slit for image exposure and the portion of the photosensitive drum that contacts the transfer sheet, and the process cartridge is removed from the image forming apparatus. At times, the leakage of external light is prevented. However, it is desirable to have as few movable parts as possible from the viewpoint of ease of assembly. The developer is mainly composed of a toner and a carrier, which are made of a colorant and a binder resin. The binder resin melts when heat or pressure is applied, and has the function of fixing the colorant to the paper. - Therefore, when the process cartridge is exposed to high temperatures due to direct sunlight, etc., the binder resin melts and a sticking phenomenon called blocking tends to occur. If blocking occurs, the next time this developing device is used, the initial image will become unclear or no image will be obtained. Furthermore, if the degree of blocking is severe, the developing sleeve will no longer rotate, and the developing device will eventually be damaged. For this reason, in order to prevent uneven image density and developer blocking, the latitude in selecting photoreceptors, developing materials, and other materials becomes narrower, making it impossible to significantly improve image quality or further reduce costs. There is. Furthermore, users must also pay attention to the storage location and storage conditions of the process cartridge. One method for solving these problems is to provide a power source and drive mechanism outside the image forming apparatus, connect the removed developing device thereto, and agitate the toner. However, with this method, each time the cartridge is removed, it must be reconnected to the external drive mechanism, and storage space is limited, making it difficult to use. There was also the problem of increased costs.

[Problem to be solved by the invention]

The present invention has been made in view of the problems of the prior art described above, and it is an object of the present invention to provide a process cartridge for realizing an image forming apparatus having excellent image quality with little environmental dependence. A further object of the present invention is to provide a process cartridge for realizing an electrophotographic image forming apparatus that is easy to handle.

[Means to solve the problem]

The present invention provides a process cartridge for use in an electrophotographic image forming apparatus in which a photosensitive drum and a process means are integrated. A process cartridge characterized by having: In the process cartridge, the stirring means may be any means as long as it can stir the developer, but is preferably a developing sleeve and/or an stirring conveyance screw. The present inventors built all the mechanisms for rotating the photosensitive drum into the process cartridge, and by rotating the photosensitive drum even when the cartridge is removed from the image forming apparatus, the generation of optical memory can be prevented even without a light-shielding shutter. However, we focused on whether it is possible to prevent the occurrence of blocking and stabilize triboelectric charging by rotating the developing sleeve and/or the agitation conveyance screw to circulate the toner. First, using a process cartridge that does not have moving parts such as a light-shielding shutter, the photosensitive drum, developing sleeve, and agitation conveyance screw are rotated by a drive mechanism provided separately from the image forming apparatus, and the rotation speed is varied and left for a long period of time. However, when I set it up in an image forming apparatus and produced an image, I found that as long as I rotated it slowly, I could always get a clear image. However, if the photosensitive drum is rotated day and night without any pauses, the surface of the photosensitive drum will gradually wear away, and its durability will be impaired, causing the life of the photosensitive drum to expire before the process cartridge reaches its original replacement time. It turned out that it reached . In addition, although tribocharging is stabilized when the developing sleeve and agitation conveyance screw are rotated, it was found that if they rotate without stopping at all or if they rotate too quickly, tribocharging becomes excessive and the toner deteriorates. . Therefore, by rotating the photosensitive drum, developing sleeve, and agitation conveyance screw only while being exposed to light, which causes optical memory toner blocking, tribocharging could be stabilized without optical memory blocking. It was found that clear images could be obtained. Next, in order to facilitate the handling of the removed process cartridge, a small motor and battery were built into the process cartridge, and sensors and controls were installed to rotate the photosensitive drum, developing sleeve, and stirring conveyance screw only while exposed to light. It was found that there were problems in that a circuit was required, and if the cartridge was stored for a long period of time, the battery might not be noticed even if it was depleted. Therefore, we are considering whether it is possible to use a solar cell as a driving power source so that the photosensitive drum, developing sleeve, and agitation conveyance screw rotate only when the process cartridge is exposed to light, the size and type of the solar cell, and the motor. After examining the system and gears, it was found that the photosensitive drum, developing sleeve, and agitation conveyance screw could be sufficiently driven using a solar cell large enough to be built into the cartridge. Furthermore, it has been found that the number of rotations of the photosensitive drum, developing sleeve, and agitation conveyance screw are automatically changed according to the amount of light hitting the cartridge, making it easier for the user to manage the process cartridge. Fig. 1 shows the external appearance of a process cartridge provided with a solar cell according to the present invention, and Fig. 2 shows a process cartridge incorporating a motor and gears inside for driving a photosensitive drum and/or a developing sleeve and/or an agitation conveyance screw. FIG. 3 is a cross-sectional view of an example of a cartridge. In FIG. 1, 101 is a solar cell, and 130 is a process cartridge body covered with a light shielding wall. In FIG. 2, 201 is a solar cell, 205 is a developing device,
214 is a cleaning device, 227 is a slit for image exposure, 230 is a cartridge body covered with a light-shielding wall, 2
81 is a gear driven by a small motor (not shown) that can be driven by a solar cell, 282 is a gear for rotating the photosensitive drum, and 283 is for rotating the developing sleeve of the developing device and/or the toner stirring and conveying screw. gear. When the process cartridge is set in the image forming apparatus, a protrusion (not shown) on the main body moves the gear 28! Since the gears 281 and 282 are not engaged with each other since they are pushed in, it can be used in the same way as a conventional process cartridge. When the process cartridge is removed from the image forming apparatus, gears 281 and 282 are engaged by a spring (not shown), and preparations are made to drive the photosensitive drum, the developing sleeve, and/or the stirring conveyance screw. A motor (not shown) is powered by the power supplied by the solar cell 201.
rotates, the photosensitive drum rotates via a speed reduction means (not shown) such as a gear, and gears 281 and 282, and the developing sleeve and/or the stirring conveyance screw rotate accordingly. Here, the speed reduction means (not shown) located between the motor and the gear 281 is configured to reduce the number of rotations of the photosensitive drum and/or developing sleeve and/or agitation conveyance screw even if the motor rotates at high speed when exposed to direct sunlight. This purpose is to prevent the deterioration of toner and the like by suppressing the noise, and to obtain the torque necessary to rotate the photosensitive drum and/or the developing sleeve and/or the agitation conveyance screw. Therefore, any known speed reduction means can be used, such as a gearbox combining large and small gears, a combination of a belt and gears, a combination of a chain and gears, etc. Further, the combination thereof may be appropriately selected so that the rotational speeds of the photosensitive drum, the developing sleeve, and the stirring and conveying screw are within a suitable range depending on the output of the solar cell, the output of the motor, and the like. Since the photosensitive drum is rotated in this manner, it is possible to prevent the generation of optical memory due to leakage of light from the outside even if movable parts such as a light-shielding shutter are omitted. Further, the developer is transported and circulated within the developing device 305 by the rotating agitation transport screw and the developing sleeve. Since the stirring conveyance screw and the developing sleeve are rotated in this manner, the binder resin is not melted and blocking can be prevented. Furthermore, since the toner is circulated, even when the process cartridge is reused, triboelectric charging is stabilized from the beginning, and clear images can be obtained. Furthermore, the output of solar cells changes depending on the intensity of the light irradiated with it, so when exposed to strong light, for example direct sunlight, the motor rotation speed will automatically increase, the developer will be well stirred, and the light will not be absorbed. By not performing unnecessary agitation when the intensity is low or at night, the toner will not deteriorate due to excessive agitation. , a timer, etc. are not required, so the structure can be simplified and all mechanisms can be built into the developing device. However, a switch, a timer, etc. may be provided as necessary. The rotation speed of the agitation conveyance screw and/or developing sleeve that agitates the photosensitive drum and/or the developer is preferably 1 rpm or more and 500 rpm or less, more preferably 5 rpm or more and 300 rpm or less, and optimally 10 rpm.
It is desirable that it is pm or more and 100 rpm or less. Although both the photosensitive drum, the developing sleeve, and/or the stirring conveyance screw are rotated here, the present invention is effective even if only one of the photosensitive drum, the developing sleeve, and/or the stirring conveyance screw is rotated. Examples of solar cells that can be used in the present invention include single crystal silicon solar cells, polycrystalline silicon solar cells, amorphous silicon solar cells, gallium arsenide solar cells, indium phosphide solar cells, other compound semiconductor solar cells, and organic semiconductor solar cells. Any solar cell can be used. Among these, amorphous silicon solar cells are suitable because they are low in cost, can be made smaller and lighter, do not pollute the environment, and have a spectral sensitivity that matches the fluorescent lamps used in office lighting. Furthermore, the present invention is effective regardless of whether the solar cell is installed on the top, front, or side surface of the process cartridge. Further, it is also possible to make the solar cell removable, remove the solar cell from a cartridge set in the image forming apparatus, and install the solar cell in the removed cartridge. Here, the area of the solar cell installed in the process cartridge is preferably 10cm or more and 500cm or less,
More preferably, the motor is 50 cm or more and 300 cm or less. As the motor that can be used in the present invention, any low power consumption, high torque DC motor such as a geared motor, coreless motor, brushless motor, etc. can be used. A current type motor is suitable. The photoreceptor used in the process cartridge of the present invention may be any of an amorphous silicon photoreceptor, an OPC photoreceptor, a Se photoreceptor, etc. Binder resins that can be used in the agent include known thermoplastic resins such as polyester resins, urethane resins, epoxy resins, ethylene-ethyl acrylate resins, phenol resins, styrene-butadiene resins, xylene resins,
Butyral resin etc. can be used. All known colorants can be used in the developer such as toner in the process cartridge of the present invention, such as carbon black, iron black, nigrosine,
These include benzidine yellow, quinacridone, rhodamine B, and phthalocyanine blue.

【Example】

EXAMPLES Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto in any way. Example 1 Using the process cartridge of the present invention shown in FIGS. 1 and 2, various image summaries of solid black, halftone, and text on an A4 size sheet were taken using the image forming apparatus shown in FIG. The cartridge was removed from the image forming apparatus and left for one month. Thereafter, when this process cartridge was loaded into the image forming apparatus again and a similar image sample was taken, a clear image was obtained from the initial image, and no change was observed compared to the image before being left. Comparative Example 1-1 When the same process as Example 1 was used except that the conventional process cartridge shown in Fig. 4 without the light-shielding shutter was used, optical memory occurred, especially in the initial image after reuse. A clear image could not be obtained. Comparative Example 1-2 In addition to the process cartridge, a photosensitive drum rotating means and a developer stirring means driven by a commercial power source other than a solar cell were provided, and the removed process cartridge was connected to it and left as was in Example 1. However, handling such as replacing and connecting the process cartridge was troublesome. In addition, because the developer was constantly stirred, the toner deteriorated, and all images had a high density and were not clear. Comparative Example 1-3 A storage battery was built into the process cartridge instead of a solar cell in the same manner as in Example 1, but the battery ran out during the process and no clear images could be obtained. Example 2 After taking an image sample using the image forming apparatus shown in FIG. 3 using the process cartridge of the present invention shown in FIGS. 1 and 2, the process cartridge was removed from the image forming apparatus and placed in a place exposed to direct sunlight. I left it alone. Thereafter, when this process cartridge was loaded into the image forming apparatus again and an image sample was taken, a clear image was obtained from the initial image, and no change was observed compared to the image before being left. Comparative Example 2 When samples were taken in the same manner as in Example 2 except that the conventional process cartridge shown in FIG. 4 was used, a clear image could not be obtained, especially in the initial image after reuse. When I disassembled the process cartridge and examined it, I found that the developer was blocking. Example 3 Comparing images before and after being left in the same manner as in Example 1 using the process cartridges shown in Figures 1 and 2 with various combinations of photosensitive drum materials and developer binder resin and colorant materials. As a result, good results were obtained in all combinations as in Example 1, and the image quality was significantly improved.

【Effect of the invention】

According to the present invention, optical memory is suppressed, image density does not become non-uniform when the process cartridge is used again after being left unused, and the degree of freedom in selecting materials for the photoreceptor is widened, thereby significantly improving image quality. Furthermore, moving parts such as light-shielding shutters can be omitted.
The process cartridge assembly is now ready. In addition, since toner blocking is suppressed, the degree of freedom in combining the colorant, binder resin, and carrier, which are the components of the toner, is increased, making it possible to dramatically improve image quality and reduce toner costs. The effect is that it can be done. Further, since the triboelectric charging of the toner is stabilized, there is an effect that when the process cartridge is reused, a clear image can be obtained from the first sheet. Furthermore, since the solar cell, motor, and gear are incorporated into the process cartridge, there is no need to separately provide a power source and drive mechanism for driving the photosensitive drum, and the process cartridge can be easily handled.

[Brief explanation of drawings]

Fig. 1 is an external view of the process cartridge of the present invention, Fig. 2 is an external view of the process cartridge of the present invention;
The figure is a partial perspective view of a process cartridge, FIG. 3 is a sectional view of an image forming apparatus having a process cartridge, and FIG.
The figure is an external view of a conventional process cartridge. 101.201 130,230,330.430 205.305 214.314 227.327,427 281, 282.283 3 (II 02 03 04 05 06 07 08 09 10 11 12 13 15 Solar battery process cartridge developer cleaning device Slit gear for image exposure Document table Imaging element array Photosensitive drum Corona charger Developing device Feeding roller Register roller Transfer charger Conveying guide Fixing device Ejection roller Tray Separating means Illumination optical system Heat ray absorption filter Image forming device Photosensitive drum protective cover Conveying roller

Claims (1)

[Claims] 1. In a process cartridge used in an electrophotographic image forming apparatus and in which a photosensitive drum and a process means are integrated, a solar cell and a photosensitive drum rotation means and/or a photosensitive drum rotation means that can be driven by the solar cell are provided. A process cartridge characterized in that it has a developer stirring means. 2. The process cartridge according to claim 1, wherein the developer stirring means is a developing sleeve. 3. The process cartridge according to claim 1, wherein the developer stirring means is an agitation conveyance screw. 4. A process cartridge used in an electrophotographic image forming apparatus in which a photosensitive drum and a process means are integrated, the cartridge having a solar cell and a motor driven by the solar cell, and the cartridge being removed from the image forming apparatus. A process cartridge characterized in that when removed, the motor is driven using the solar cell as a power source, and the photosensitive drum is rotated by the motor.