JPH03260673A - Image forming device - Google Patents

Abstract

PURPOSE:To stabilize an electrostatic charging potential and to obtain a high-quality image by providing an image carrier having a photoconductor which performs positive electrostatic charging, a scorotron type electrostatic charger and a transfer roller. CONSTITUTION:A photosensitive drum 4 is provided with a photoconductive layer 46 on an Al base body 45. The layer 46 is obtained by superposing a charge transportation layer 47, a charge generation layer 48 and an urethane/Si resin layer 49 on the Al base body 45. The drum 4 is stably electrostatically charged to be positive in s specified manner by the scorotron type electrostatic charger 52 with high accuracy and exposed through a gap 51. Light is cast to the layer 48 and a negative charge is generated. The generated positive charge is erased with the negative charge, and the positive charge flows to the base body 45 through the layer 47. Then, a part where the light is received becomes potential zero, and an electrostatic latent image is formed. The latent image is developed with the developer supplied by a roller 11. A conductive rubber roller 36 is electrostatically to be negative and electric field is generated between the drum 4 which is electrostatically charged to be positive and the roller 36 so as to transfer the image to a transfer material fed to a paper passing path 37. By adopting the transfer roller, O3 is restrained from being evolved and the image is stably supplied for a long time without clarifier.

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, and a printer that forms an image using an electrophotographic method. 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 apparatus is disclosed 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.

Generally, an image carrier having a photoconductor that is negatively charged is used, and the charger is used to charge the photoconductor negatively by corona discharge, and the charger has a stable band! A scorotron is used to obtain the electrical potential. A corotron transfer charger provided in the main body of the apparatus is used as a means for transferring an image formed on an image carrier by charging, exposure, and development to a transfer material.

Further, an image forming apparatus is also known in which an image bearing member having a negatively charged photoconductor is charged by a charging roller and transferred onto a transfer material by a transfer roller.

Problem to be Solved by the Invention However, when an image bearing member having a negatively charged photoconductor and a scorotron charger that discharges a negative charge are combined and integrated in an image forming cartridge, the surrounding corona wire of the charger Although it is easy to get dirty due to dust adhering to the image forming cartridge, it is difficult to clean because it is located inside the image forming cartridge, and harmful ozone is generated due to the discharge of negative charge by the charger. The problem is that a large amount of

Furthermore, in the case where a charging roller and a transfer roller are used for an image bearing member having a negatively charged photoconductor,
Although the generation of ozone can be suppressed by using a charging roller as a charging means, it is difficult to obtain a stable charging potential.
A problem arises in that the image quality deteriorates.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image forming apparatus in which the charging means is less likely to be contaminated, the generation of ozone can be suppressed, the charging potential is stable, and high quality images can be obtained.

Means for Solving the Problems In order to achieve the above-mentioned problems, the present invention provides an image forming cartridge in which an image bearing member and at least a charging means are integrally combined, which is detachably attached to an apparatus main body. The forming apparatus is characterized in that the image carrier is provided with a positively charged photoconductor, and a transfer roller is provided as a transfer means for transferring the image on the image carrier to a transfer material.

Preferably, the charging means is a scorotron type charger.

The present invention also provides an image forming apparatus that includes an image carrier having a positively charged photoconductor, a Scorotron type charger, and a transfer roller.

Effects In the above structure of the present invention, since the image bearing member has a positively charged photoconductor, harmful ozone is not generated during charging unlike in the case of charging with a negative charge, and the charging means does not generate harmful ozone. Since it does not generate dirt and requires almost no cleaning, stable images can be obtained over a long period of time even when it is integrated into an image forming cartridge. On the other hand, due to the use of a positively charged image carrier, there is a risk that ozone will be generated if a corotron type transfer charger is used as a transfer means, but ozone generation is suppressed by using a transfer roller as a transfer means. can do. Further, even if the transfer roller becomes dirty, it can be easily cleaned, and since there is a margin of accuracy in charging potential during transfer, there is no problem in transferability even when the transfer roller is used in a transfer row.

Further, when a scorotron type charger is used as the charging means, the charging potential is stabilized and a high quality image can be obtained.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 to 8.

In FIG. 1 showing the basic configuration, 1 is an image forming cartridge, and a photosensitive drum 4 has a positively charged photoconductor.
It is equipped with This photosensitive tram 4 has a photoconductor layer 46 on an aluminum base 45, as shown in FIG. This photoconductor layer 46 consists of a charge transport layer 47 on an aluminum substrate 45, a charge generation layer 48 thereon, and an overcoat layer 49 made of a highly wear-resistant urethane/silicon resin that protects the surface. .

After the photosensitive drum 4 is positively charged to a predetermined charging potential with high accuracy and stability using a scorotron type charger 52, it is exposed through an exposure slit 751. When light hits the charge generation layer 48, positive and negative charges are generated, the charged positive charges are erased by the generated negative charges, and the generated positive charges flow to the aluminum base 45 through the charge transport layer 47. In this way, the portion hit by the light becomes 0 potential, and an electrostatic latent image is formed. The electrostatic latent image on the photosensitive tram 4 is formed by the developing roller 11.
It is developed with the developer supplied at , and reaches the contact point with the paper passing bus 37 . A transfer roller 36 is disposed facing the photosensitive drum 4 with the paper passing bus 37 therebetween. The transfer roller 36 is made of conductive rubber or the like, and is negatively charged to form a transfer electric field between it and the photosensitive drum 4, and the image developed on the photosensitive drum 4 is sent onto the paper bus 37. The image is transferred to the transfer material. During this transfer, there is a margin in the accuracy of the charging potential, so there is no problem with the transfer performance even with the transfer roller 36. As described above, by using the positively charged photosensitive tram 4, harmful ozone is generated during charging during charging 52. There is no need for cleaning as there is no dirt or stains. Therefore, even if they are integrally combined in the image forming cartridge 1, stable images can be obtained over a long period of time.

On the other hand, if you use the transfer roller 36, the band! Since the electric potential can be lowered and corona discharge does not occur, it is possible to suppress the generation of ozone even if it is negatively charged. Also, since the transfer roller 36 is provided separately from the image forming cartridge 1 via a paper passing bus 37, it is possible to prevent dirt from forming. It can also be cleaned easily.

The other components in FIG. 1 will be described below with reference to FIG. 3 for a concrete example of this embodiment.

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 at the rear of the photosensitive tram 4 to scrape the toner scraped from the photosensitive tram 4 into the waste toner casing 3.

A developing roller 11 for developing an electrostatic latent image on the photosensitive drum 4 with toner is provided at the connecting end of the developing device casing 2 and is pivotally supported by a shaft 12 on a side wall. 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.

At the back of the sponge roller 13, a wire 82 is provided for scraping off the development stains. 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. Returned to 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 3 and covers the waste toner casing 3, making it easy to handle the image forming cartridge 1 as an integral part. In particular, the lid 30 is heavier than the waste toner casing 3 and is fixed to the side of the larger developer casing 2 to serve as the gripping portion H for integral handling, so that the stability of the image forming cartridge 1 during handling is improved. This makes it easier to handle. Note that there is provided an amount of play between M2O and the waste toner casing 3 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 seal 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 is in 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.

Further, as shown in detail in FIG. 1, at the bottom of the connecting end opening of the developer casing 2, there is provided a seal plate 25 on the rear side of the seal plate 25 in the direction of rotation of the developer roller 11 so as to cover the space below the developer roller 11. A shallow container-shaped spill prevention part 27 is provided, and a plurality of ribs 28 are provided on the inner bottom surface thereof and extend to a position facing the outer peripheral surface of the developing roller 11 with a small gap therebetween.
are arranged in parallel in the rotational direction of the developing roller 11. As a result, the developer that falls off from the outer circumferential surface of the developing roller II before reaching the seal plate 25 or while passing through the seal plate 25 falls into the spill prevention part 27 and is collected. Since the agent does not leak outside unless it passes through the narrow gap between the upper ends of the plurality of ribs 28 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 arranged in a narrow space between the developing roller 11 and the paper passing path 37 without any problem.

This image forming cartridge 1 is used by being attached to a printer 31 shown in FIG. 4, for example. 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 mounted on the upper frame 33 as shown 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 upper frame 33 of the image forming cartridge 1 is closed with respect to the lower frame 32,
Transfer charger 3 provided on the lower frame 32 side
A paper passing path 37 for printing is formed between the upper frame 33 and the upper frame 33 as shown in FIG. 4, and the paper passing path 37 is opened to facilitate troubleshooting such as jams. .

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 emitting source modulated according to an image signal provided by a personal computer, an image reader, etc., using an appropriate scanning means such as a polygon mirror, and scans the photosensitive drum 39. Image exposure is performed on the photosensitive drum 4 toward the image. For this image exposure, an exposure slit 51 is provided in a part of the lid 30 of the image forming cartridge 1 to enable image exposure to the photosensitive drum 4. 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 so that an image is formed.

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 1, causing deformation such as twisting or denting. It may occur temporarily. At this time, the volume of the developer casing 2 momentarily decreases, 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 30, and the opening 84 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 developing device casing 2 is deformed as described above during handling of the image forming cartridge L, resulting in a reduction in volume and internal air blowing out, the semi-permeable membrane with low resistance prevents the air blowing out. 85, and even if the developer tries to get on the blown air, the semipermeable 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, the developer is compressed into a single layer with a predetermined thickness by the pressure contact of the elastic plate 41, but 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 be produced.

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 facing the developer carrying area X and the developer non-carrying area Y of the developing roller 11, and the sections 41a and 41b on both sides thereof. 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. Part 4 of the elastic blade 41
1b can be brought into close contact with the portion of the developer non-carrying area Y, as shown in FIG. 6, regardless of the portion 41a of the elastic blade 410 that is pushed away by the developer in the developer carrying area X. Therefore, the elastic blade 41
It is possible to eliminate the inconvenience in which the developer floats from the developing roller 11 in the developer non-carrying area Y and the developer leaks from the developer non-carrying area Y to the photosensitive drum 4 side.

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, and the pressing force on the developing roller 11 is reduced, and the elastic blade 41 has a long duration (pressing force of the entire portion 41a on the developing roller 11). become equal.

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 satin surface during resin molding without sandblasting, the cost of the boundary image roller 11 is reduced accordingly, and the developer can be transported to areas where the electric field is not diffused. At the same time, the gap between the developing roller 11 and the photosensitive drum 4 can be shortened in a pseudo manner beyond the discharge limit.
Resolution in development is improved.

As another example, an insulating elastic roller may be used instead of the elastic plate 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, the developer side supply mechanism, and the 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 (Fig. 3, Fig. 7). 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 controllability of charging by exhibiting charging characteristics as described above.

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, two chargers, a corotron type charger and a scorotron type charger, may be installed. Further, the size of the mesh may change continuously or discontinuously. The charger 52 has a grid portion 53 for miniaturization.
and the discharge stabilizing frame 54 are integrally formed by 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 IE 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 pinked up and fed by the pickup roller 93 from the paper feed force center 92 in a stopped state, and then feeds the transfer paper 91 at a predetermined timing. The leading edge of the photosensitive drum 4 is aligned with the toner image formed on the photosensitive drum 4 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, there is a light receiving end 65a of the optical fiber halo 5.
is positioned facing the photosensitive drum 4. The optical fiber 65 is configured to guide 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 whether there is a shortage or deterioration of the developer, and to take measures such as warning of the usage limit due to the life of the image forming cartridge 1 or stopping 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 waste toner casing 3 can be punched out from a PET sheet to reduce costs, and the waste toner casing 3 is provided with an unused detection mechanism 71 that is 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's 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 nozzle 1 is attached to 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 l 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 cart RINON 1, and to issue a restriction or warning if the number of prints exceeds a predetermined number based on this count.

On the other hand, if the image forming cartridge 1 to be installed has already been used, the detection pin 78 is retracted to the waste toner casing 3 side, so that the image forming cartridge 1 is not installed in the upper frame 33. However, the switch 94 cannot be pressed. Therefore, the unused imaging cartridge number 1
No action will be taken as would be the case if the

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.

Effects of the Invention According to the present invention, since an image carrier having a photoconductor that is positively charged is used, no harmful ozone is generated during charging, and no dirt is generated on the charging means. By using this, it is possible to suppress the generation of ozone in the transfer section, and therefore, it is possible to reduce the generation of ozone in the charging and transfer section, and it can be used for a long time without cleaning the charging section in an image forming cartridge that is difficult to clean. The effect is that a stable image can be obtained over a long period of time.

Further, by using a scorotron type charger as the charging means, in addition to the above effects, the charging potential is stabilized and a high quality image can be obtained.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of a main part of an embodiment of the present invention, FIG. 2 is a partially enlarged sectional view of a photosensitive drum, and FIG. 3 is an image forming cartridge in a printer to which the embodiment is specifically applied. 4 is a front view showing a schematic configuration of the printer; FIG. 5 is a perspective view of the developing roller; FIG. 6 is an enlarged front view of a portion of the developing roller; FIG. 8 is a partially enlarged sectional view of the charger, and FIG. 8 is a sectional view of a portion of the waste toner casing showing the unused detection mechanism of the image forming cartridge.

Claims (3)

[Claims] (1) In an image forming apparatus in which an image forming cartridge in which an image bearing member and at least a charging means are integrally combined is removably attached to the main body of the apparatus, the image bearing member is provided with a positively charged photoconductor; An image forming apparatus characterized in that a transfer roller is provided as a transfer means for transferring an image on an image carrier to a transfer material. (2) The image forming apparatus according to claim 1, wherein the charging means is a scorotron type charger. (3) an image carrier having a positively charged photoconductor;
An image forming apparatus comprising a scorotron type charger and a transfer roller.