JPH04356091A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device where conduction is surely attained even in a known belt-like latent image carrier and an abnormal image is prevented from being formed without providing a special conductive member such as a grounding member. CONSTITUTION:This is an image forming device which is provided with the belt-like latent image carrier 13 wound around plural rollers 14 and where the image is formed by impressing bias on the conductive layer of the carrier 13 and grounding there so that the electrostatic latent image on the carrier 13 may be developed. In this device, a guiding member 27 for positioning the carrier 13 at an exposing position is arranged inside the carrier 13, and a conductive part which contacts with the conductive layer of the carrier 13 is formed on the surface of at least one part of the guiding member 27.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention applies a bias to a conductive layer of a belt-shaped latent image carrier wound around a plurality of rollers and grounds the electrostatic latent image on the latent image carrier. The present invention relates to an image forming apparatus that visualizes images.

0002

2. Description of the Related Art Conventionally, an image forming apparatus that visualizes an electrostatic latent image by grounding a belt-shaped latent image carrier is disclosed, for example, in Japanese Patent Laid-Open No. 2-100082. There is something. As shown in FIG. 10, a predetermined tension is applied to the photoreceptor belt 1 as a latent image carrier by a roller (not shown), and a photoreceptor layer 3 is formed on the surface of the conductive layer 2. There is. A ground member 4 is located on the surface side of the photoreceptor belt 1, and by bringing the ground member 4 into contact with the conductive layer 2, the conductive layer 2 is grounded. In this case, since the grounding is performed directly from the part of the photoreceptor belt 1 that is always stretched along the roller, even if the photoreceptor belt 1 is deformed, the contact between the grounding member 4 and the conductive layer 2 is maintained. Defects can be suppressed.

As mentioned above, the conductive layer 2 of the photoreceptor belt 1
The method for establishing electrical conduction with the photoreceptor belt 1 is to contact the grounding member 4 with the part of the conductive layer 2 where the front end of the photoreceptor belt 1 is exposed and the back side contacts the roller, so that it is always in a stable state. This prevents contact failure between the two.

0004

[Problem to be solved by the invention] However, FIG.
In the photoreceptor belt 5 shown in FIG. 1, a photoreceptor layer 7 is generally laminated only on the central effective area of the surface of a conductive layer 6 made of a metallic material, and toner is prevented from adhering to the other end areas. An insulating layer 8 is formed for this purpose. Therefore, the photoreceptor belt 1 as shown in FIG.
A structure in which the conductive layer 2 is exposed only at one end and the rest is the photosensitive layer 3 is expensive because it is a custom-made product rather than a general construction. In addition, in such a configuration, since the conductive layer 2 is exposed, if foreign matter enters from the outside, there is a risk that the foreign matter will come into contact with the conductive layer 2, and toner may adhere to the conductive layer 2. Since there is a very high possibility that toner will accumulate, there is a risk that the toner may cause poor contact or cause background stains on the output image.

[0005] In view of these points, FIG. 12 (
As shown in a), a ground member 11 is arranged inside the photoreceptor belt 10 wound between a plurality of rollers 9, and this earth member 11 is brought into contact with the back side of the photoreceptor belt 10. be. In this case, since grounding (continuity) is performed from inside the photoreceptor belt 10, the above-described problems caused by toner and foreign matter coming into contact with the conductive layer 2 can be solved. However, as shown in FIG. 12(b), the problem of poor contact occurs due to deformation A of the photoreceptor belt 10 (roller curl, waving, etc.).

[0006]

[Means for Solving the Problems] The invention according to claim 1 has a belt-like latent image carrier wound around a plurality of rollers, and a bias is applied to a conductive layer of the latent image carrier. In an image forming apparatus that forms an image by grounding and visualizing an electrostatic latent image on the latent image carrier, the guide member for positioning the latent image carrier at the exposure position is provided as described above. A conductive portion is disposed inside the latent image carrier and is in contact with the conductive layer of the latent image carrier on at least a portion of the surface of the guide member.

[0007] The invention according to claim 2 has a belt-like latent image carrier wound around a plurality of rollers, and a bias is applied or grounded to the conductive layer of the latent image carrier to conduct the latent image carrier. In an image forming apparatus that forms an image by visualizing an electrostatic latent image on an image carrier, at least a portion of the roller is connected to the conductive layer of the latent image carrier on the surface of at least one of the rollers. A contacting conductive part was formed.

[0008] The invention according to claim 3 has a belt-like latent image carrier wound around a plurality of rollers, and a bias is applied or grounded to the conductive layer of the latent image carrier to conduct the latent image. In an image forming apparatus that forms an image by visualizing an electrostatic latent image on an image carrier, a guide member for positioning the latent image carrier at an exposure position is provided inside the latent image carrier. A conductive portion that contacts the conductive layer of the latent image carrier is formed on at least a part of the surface of the guide member, and a slip promoting member that promotes slip is formed on the other surface.

[0009]

[Operation] In the invention as claimed in claim 1, since grounding (continuity) is performed using a guide member that positions the latent image carrier at the exposure position from inside the latent image carrier, the latent image carrier has a special configuration. Furthermore, even if the latent image carrier is deformed due to curling, waving, etc., it will surely contact the guide member, so that stable grounding can always be performed.

In the invention as claimed in claim 2, since grounding is performed using a roller that rotates the latent image carrier,
In addition to having the same effect as the invention according to claim 1, an image forming apparatus that performs exposure without using a guide member that positions the latent image carrier at the exposure position from inside the latent image carrier, and a latent image carrier that contacts a roller. This can be particularly effective for image forming apparatuses that expose the front surface side of the image forming apparatus.

In the invention as claimed in claim 3, grounding is performed using a guide member for positioning the latent image carrier at the exposure position from inside the latent image carrier. In addition to being able to obtain similar effects, smooth and always stable rotation of the latent image carrier can be obtained by protecting the contact surface between the guide member and the latent image carrier by the slippage promoting member and promoting slippage. It becomes possible.

0012

[Embodiment] A first embodiment of the present invention will be explained based on FIGS. 1 and 2. FIG. 2 shows an example of a well-known image forming apparatus, and FIG. 1 shows an enlarged photoreceptor unit according to the present invention. First, the overall configuration of the image forming apparatus will be outlined based on FIG. 2. A photoreceptor unit 12 is provided in the center of the main body of the apparatus, and a photoreceptor belt 13 serving as a latent image carrier is given a predetermined tension by three rollers 14 provided on the inside (back side). It has a rolled shape. Around the surface side of the photoreceptor belt 13, an optical writing unit 15, an electrostatic charger 16, a cleaning unit 17, a transfer charger 18
, furthermore, a developing unit 2 equipped with a developing sleeve 19
0 etc. are arranged. Further, a paper feed unit 21 is disposed below the main body of the apparatus, and the recording paper 22 is separated and fed one by one via a paper feed roller 23. The fed recording paper 22 is sent to a conveyance path 24 provided above the paper feeding unit 21, and is subjected to a transfer process by the transfer charger 18. Furthermore, a fixing unit 25 and a paper ejection unit 26 are sequentially arranged on a path opposite to the transport path 24 via the transfer charger 18. As a result, the recording paper 22 transferred by the transfer charger 18 is fixed by the fixing unit 25 and discharged to the paper discharge unit 26, thereby completing a series of image forming operations.

Next, the state of the peripheral portion of the photoreceptor belt 13 will be explained based on FIG. 1. In this case, the photoreceptor belt 13
11, a photosensitive layer 7 is laminated at the center of the surface of a conductive layer 6 made of a metallic base material, and an insulating layer 7 is provided at both end areas to prevent toner from adhering. A conductive layer 6 is formed on the back side of the layer 8.
is exposed. In order to maintain the relative position between the optical writing unit 15 and the photoreceptor belt 13 at the exposure position P, the guide member is placed in contact with the back side of the photoreceptor belt 13 with respect to the optical writing unit 15. A facing roller 27 is provided. The opposing roller 27 is rotatable to prevent damage to the photoreceptor belt 13. The photoreceptor belt 1 is attached to such an opposing roller 27.
3, a conductive portion 27a is formed on at least a portion of the surface of the contact portion. Here, a plate-shaped ground terminal 29 is brought into contact with the rotating shaft 28 of the opposing roller 27 to release the charges attached to the photosensitive layer 7.

Next, various modifications of the first embodiment described above will be described based on FIGS. 3 to 5. First, FIG. 3 shows a first modification thereof, in which the opposing roller 27 is made of a conductive material such as aluminum. Further, FIG. 4 shows a second modification example, in which an elastic member 30 (for example, rubber, urethane, etc.) as a slip promoting member is wrapped around the surface of the opposing roller 27. It is. Thereby, damage to the contact surface with the photoreceptor belt 13 and occurrence of slippage can be prevented. However, in this case, since the opposing roller 27 always needs a conductive area, the elastic member 30 is not wrapped around the part of the photoreceptor belt 13 that is in contact with the outside of the effective area, and the conductive part 27a is connected to the conductive layer 6. It is formed to have the same diameter as the region of the elastic portion so as to be in direct contact with it. Furthermore, FIG. 5 shows a third modification, in which a conductive brush roller 31 is used as the guide member instead of the facing roller 27 as described above. In this case, in order to prevent the position of the photoreceptor belt 13 from moving, it is necessary to form the brush 31a with care in the material, wire diameter, density, hair length, etc. Note that in all of the examples described so far, the ground terminal 29 is a plate-like member, but as another method, a brush or a pin-like member, etc. may be used, and the method of contact with the opposing roller 27 is also the same as described above. It is not limited to the examples.

As described above, since the ground (continuity) is established using the facing roller 27 that positions the photoreceptor belt 13 at the exposure position P from the inside, the photoreceptor belt 1
3 need not have a special configuration as in the past, and this makes it possible to provide an inexpensive device. In addition, even if the latent image carrier is deformed due to curling or waving, it will surely contact the guide member, making it possible to always perform stable grounding, thereby preventing the occurrence of abnormal images. can. Furthermore, since continuity is established using existing components, there is no need to provide a conventional grounding member (special conductive member) such as a brush, and since continuity is established from inside the photoreceptor belt 13, Adhesion of toner and contact of foreign matter to the conductive layer 6 can be prevented, and stable conduction can always be achieved.

[0016] Also, the opposing roller 27 by the elastic member 30
By protecting the contact surface between the photoreceptor belt 13 and preventing the occurrence of slippage, smooth and always stable rotation of the photoreceptor belt 13 can be obtained, and reliable conduction can be achieved.

Next, a second embodiment of the present invention will be explained based on FIG. Here, a facing plate 32 is used as the guide member instead of the aforementioned facing roller 27. As a result, the use of the opposing plate 32 is more advantageous than the opposing roller 27 in terms of simplifying the components, cost, and miniaturization.

Next, various modifications of the second embodiment described above will be explained based on FIGS. 7 and 8. FIG. 7 shows a first modification example, in which the opposing plate 32 is made of a conductive material such as aluminum. The opposing plate 32 is maintained at a relative position between the optical writing unit 15 and the photoreceptor belt 13, and two brackets 3 are provided at both ends of the opposing plate 32.
3 is supported by the housing 12a of the photoreceptor unit 12. In this case, grounding is performed through the screws 34 fixing the bracket 33 to the housing 12a from the opposing plate 32.

FIG. 8 shows a second modification example, in which the surface of the opposing plate 32 is coated with Teflon (not shown) as a slip promoting member (coating area B). It is. However, facing plate 3
Since the conductive layer 2 must have a conductive part, the conductive part 32a (conductive area C) was made to come into contact with the conductive layer 6 without coating the part of the photoreceptor belt 13 that is in contact with the outside of the effective area. .

Next, a third embodiment of the present invention will be explained based on FIG. This is designed to perform grounding using at least one of the three rollers 14 that apply a predetermined tension to the photoreceptor belt 13. Further, similar to the conductive portion 27a of the opposing roller 27 in FIG. 1 of the first embodiment described above, the roller 14 is not shown on a part of the surface of the contact portion in order to establish conduction with the photoreceptor belt 13. A conductive part is formed. Further, other constituent elements can be created with reference to various modifications of the first and second embodiments described above, so detailed explanations will be omitted here.

[0021]Although each of the embodiments described above has been described with respect to grounding, the same can be applied to the case of applying a bias.

[0022]

Effects of the Invention The invention according to claim 1 has a belt-like latent image carrier wound around a plurality of rollers, and a bias is applied or grounded to the conductive layer of the latent image carrier. In an image forming apparatus that forms an image by visualizing an electrostatic latent image on a latent image carrier, a guide member for positioning the latent image carrier at an exposure position is provided inside the latent image carrier. Since the conductive portion that contacts the conductive layer of the latent image carrier is formed on at least a part of the surface of the guide member, it is possible to use the guide member to position the latent image carrier at the exposure position from inside the latent image carrier. Since it is grounded, there is no need to make a special structure for the latent image carrier, which allows for a much cheaper structure, and also prevents deformation of the latent image carrier due to curling, waving, etc. Since it also reliably contacts the guide member, stable bias application or grounding can be performed at all times, making it possible to prevent abnormal images from occurring.

The invention according to claim 2 has a belt-like latent image carrier wound around a plurality of rollers, and the latent image is formed by applying a bias or grounding to the conductive layer of the latent image carrier. In an image forming apparatus that forms an image by visualizing an electrostatic latent image on a carrier, there is provided a conductive portion on the surface of at least one of the rollers, at least a part of which contacts the conductive layer of the latent image carrier. As a result, in addition to having the same effect as the invention described in claim 1, it is possible to avoid contact with an image forming apparatus that exposes without using a guide member that positions the latent image carrier at the exposure position from inside the latent image carrier, or a roller. This is particularly effective for image forming apparatuses that expose the front side of a latent image carrier.

The invention according to claim 3 has a belt-like latent image carrier wound around a plurality of rollers, and the conductive layer of the latent image carrier is applied with a bias or grounded. In an image forming apparatus that forms an image by visualizing an electrostatic latent image on an image carrier, a guide member for positioning the latent image carrier at an exposure position is provided inside the latent image carrier. A conductive part that contacts the conductive layer of the latent image carrier is formed on at least a part of the surface of the guide member, and a slip promoting member that promotes slip is formed on the other surface. It is possible to obtain the same effect as the invention described in item 1, and the sliding promoting member protects the contact surface between the guide member and the latent image carrier and promotes sliding, so that the latent image carrier is smooth and always stable. It is possible to obtain rotation and to perform reliable conduction.

[Brief explanation of drawings]

FIG. 1 is a side view showing the configuration around a photoreceptor unit according to a first embodiment of the present invention.

FIG. 2 is a longitudinal side view showing the overall configuration of the image forming apparatus.

FIG. 3 is a front view showing a first modification of the first embodiment.

FIG. 4 is a front view showing a second modification of the first embodiment.

FIG. 5 is a front view showing a third modification of the first embodiment.

FIG. 6 is a side view showing a configuration around a photoreceptor unit according to a second embodiment of the present invention.

FIG. 7 is a front view showing a first modification of the second embodiment.

FIG. 8 is a front view showing a second modification of the second embodiment.

FIG. 9 is a side view showing the configuration around a photoreceptor unit according to a third embodiment of the present invention.

FIG. 10 is a side view showing an example of grounding of the photoreceptor belt.

FIG. 11 is a side view showing the configuration of a photoreceptor belt.

FIG. 12 shows how the grounding member is placed inside the photoreceptor belt; (a) is a side view showing normal operation, and (b) is a side view showing the belt deformed. FIG. 3 is a side view showing a situation where a contact failure occurs.

[Explanation of symbols]

6 Conductive layer 13 Latent image carrier 14 Roller 27 Guide member 27a Conductive part 30 Slip promoting member 31 Guide member

Claims (3)

[Claims] 1. A belt-like latent image carrier wound around a plurality of rollers, and a conductive layer of the latent image carrier is applied with a bias or grounded to reduce the electrostatic charge of the latent image carrier. In an image forming apparatus that forms an image by visualizing a latent image, a guide member for positioning the latent image carrier at an exposure position is disposed inside the latent image carrier, and the guide member is arranged inside the latent image carrier. An image forming apparatus characterized in that a conductive portion that contacts the conductive layer of the latent image carrier is formed on at least a part of the surface of the member. 2. A belt-shaped latent image carrier wound around a plurality of rollers, and a bias is applied or grounded to a conductive layer of the latent image carrier to reduce the electrostatic charge of the latent image carrier. In an image forming apparatus that forms an image by visualizing a latent image, a conductive portion is formed on the surface of at least one of the rollers so that at least a portion of the roller contacts the conductive layer of the latent image carrier. An image forming apparatus characterized by: 3. A belt-shaped latent image carrier wound around a plurality of rollers, and a bias is applied or grounded to a conductive layer of the latent image carrier to reduce the electrostatic charge of the latent image carrier. In an image forming apparatus that forms an image by visualizing a latent image, a guide member for positioning the latent image carrier at an exposure position is disposed inside the latent image carrier, and the guide member is arranged inside the latent image carrier. An image forming apparatus characterized in that a conductive portion that contacts the conductive layer of the latent image carrier is formed on at least a part of the surface of the member, and a slippage promoting member that promotes slippage is formed on the other surface.