JPH07248702A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device capable of further simplifying the supporting constitution of a photoreceptor, further reducing the cost and simultaneously allowing the photoreceptor and image forming elements to come into close contact with each other by adopting the supporting constitution of the photoreceptor so that the disadvantages of both belt and drum photoreceptors are eliminated and their advantages are taken. CONSTITUTION:A cylindrical member 1 having an opening part, 1A is fixed in an immobile state in an image forming device main body. A belt-like photoreceptor 2 is wound on the cylindrical member 1 and a developing roller 6 as one of the image forming elements is brought into contact with the part 2A of the photoreceptor located in the opening part 1A with prescribed pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus in which an endless belt-shaped photosensitive member is wound around a cylindrical member which is held stationary with respect to the main body of the image forming apparatus.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer or a facsimile, an endless belt is used as a photoconductor, and the photoconductor is constructed as a belt photoconductor magazine which is detachable from the main body of the image forming apparatus. A plurality of support rollers for winding and supporting the photoconductor,
A belt housing or the like for covering the photoconductor is required, which increases the cost.

In this type of image forming apparatus, a belt-like photosensitive member is provided with a belt-like step portion for preventing meandering, and the step portion is engaged with the end portion or groove of the support roller. Thus, the meandering of the photosensitive member while traveling is prevented. For example, a belt-shaped photosensitive member is provided with a stepped portion formed of a guide member such as hot melt or rubber fused to the back surface. However, if such a member is provided on the photosensitive member, the running cost of the photosensitive member increases. , Users will be required to bear a higher cost burden.

Although the belt photosensitive member has such weak points, when such a belt photosensitive member is used, for example, the developing roller and the photosensitive member of a developing unit for visualizing an electrostatic latent image formed on the photosensitive member are exposed. Since the adhesion to the body becomes better, the fine line reproducibility of the image is improved and a high density image can be obtained. Further, a contact developing system in which a thin layer of high-resistance single-component toner is formed on a developing roller and the developing roller is brought into contact with a photosensitive member to perform development can be employed in combination with a belt photosensitive member. As described above, the belt photoreceptor has both weak points and long points.

On the other hand, when a rigid drum-shaped photoconductor is used as the photoconductor, it is difficult to control the mutual position between the photoconductor and the developing roller.
It is difficult to adopt the above contact development method. Although the drum photoconductor has such weak points, it can be handled by the drum alone, which is advantageous in terms of cost. As described above, the drum photoconductor also has weak points and strong points.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to eliminate the weak points of the belt photosensitive member and the drum photosensitive member, to take advantage of the advantages of both, and to further simplify the supporting structure of the photosensitive member and its An object of the present invention is to provide an image forming apparatus that can achieve further cost reduction.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a cylindrical member that is held stationary with respect to the image forming apparatus main body, and an endless belt that is wound around the outer peripheral surface of the cylindrical member. -Shaped photoconductor, a driving member that rotationally drives the photoconductor around a cylindrical member, and an image forming element that contacts a part of the photoconductor from the outside of the photoconductor. Provided at a part of the tubular member is a photoconductor escape portion that allows the movement of the photoconductor portion in contact with the image forming element inwardly of the tubular member while applying tension to the photoconductor when brought into contact with the body. It proposes an octopus structure.

It is effective that the image forming element is a developing roller for visualizing the electrostatic latent image formed on the photosensitive member.

Further, it is effective that the drive member is also used as the photoconductor charging roller.

Further, a photosensitive member meandering prevention member for restricting the movement of the photosensitive member in the axial direction of the cylindrical member when the photosensitive member is rotationally driven is provided on an element other than the photosensitive member, and the photosensitive member meandering prevention member is provided. It is effective to operably support the photosensitive member at a position retracted from the attachment / detachment path for the cylindrical member when the photosensitive member is replaced.

Further, it is effective to provide a photosensitive member cleaning means for cleaning the back surface of the photosensitive member.

Further, the image forming element is a cleaning blade made of an elastic thin plate for scraping off and removing the residual toner on the photoconductor, and the edge portion of the cleaning blade is in close contact with the photoconductor. It is effective to provide a magnetic force generation source that attracts the blade with a magnetic force inside the cylindrical member.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic sectional view showing only the main part of an image forming apparatus according to an embodiment of the present invention. For convenience, hatching showing the section is omitted (FIGS. 3, 5, and 8). The same applies to FIGS. 10 and 12. In FIG.
Reference numeral 1 indicates a cylindrical member made of a rigid body such as metal or synthetic resin. In this example, the tubular member 1 is made of a conductor such as metal and is held stationary with respect to the main body of the image forming apparatus. Further, the tubular member 1 of the present example has a substantially C-shaped cross section in which a part of the cylindrical body is cut out along the axial direction of the member, and the cutout portion becomes the opening 1A, This will be the photoconductor relief portion described later.

A flexible endless belt-shaped photosensitive member 2 is wound around the outer peripheral surface of the cylindrical member 1 thus constructed. That is, the photoconductor 2 is covered with the cylindrical member 1 elongated in the axial direction in a sheath shape. The photoconductor 2 has a substrate made of nickel, for example, and a photosensitive layer coated on the surface of the substrate, for example, an OPC photosensitive layer.

A driving member 3 for rotationally driving the photosensitive member 2 around the cylindrical member 1 is pressed against the photosensitive member 2, and in this embodiment, this is a driving roller. It is also used as a charging roller. Hereinafter, this is referred to as a “drive / charging roller”.

The driving / charging roller 3 is driven to rotate in the counterclockwise direction in the drawing, and frictionally feeds the photosensitive member 2 around the cylindrical member 1 to rotate it in the direction of arrow a. At the same time, the driving / charging roller 3 uniformly charges the surface of the photoconductor 2 to a predetermined polarity by the voltage applied to the roller. In this way, if the roller 3 is also used as a drive / charging roller and the drive member for driving the photoconductor 2 is also used as a photoconductor charging roller, a dedicated drive member is not required, and the device configuration can be simplified. At the same time, the device cost can be reduced.

After the surface of the photoconductor 2 is uniformly charged,
By performing optical writing or image exposure in the exposure unit 4, a predetermined electrostatic latent image is formed on the surface of the photoconductor 2.

A developing unit 5 is disposed opposite to the photoconductor portion 2A located in the opening 1A, and a developing roller 6 provided in this unit is provided with a predetermined pressure from the outside of the photoconductor 2 to the photoconductor portion 2A. It comes in contact with. As a result, a predetermined tension is applied to the photoconductor 2. The one-component magnetic toner T is accommodated in the developing casing 7 of the developing unit 5, and is agitated by the rotation of the agitator 8 and supplied onto the developing roller 6 having the magnetized layer 6a on the outer peripheral portion.

The developing roller 6 is driven to rotate counterclockwise in the figure, and at this time, the supplied toner is carried while being magnetically carried on the outer peripheral surface thereof, and during the carrying, the carried toner is carried. Is thinned by the toner thinning blade 10. Thereafter, the thinned toner is transferred to the photosensitive member 1 in the developing region where the developing roller 6 contacts the photosensitive member portion 2A.
It is used for visualizing the electrostatic latent image formed on the surface. That is, the electrostatic latent image is visualized as a toner image. Reference numeral E in FIG. 1 indicates a power source for applying a bias voltage to the developing roller 6.

Next, the toner image formed on the photoconductor 2 is transferred onto the recording paper 13 by the action of the transfer charger 12. On the other hand, the surface of the photoconductor 2 after the transfer is removed by the static elimination light 1
Then, the cleaning blade 16 of the cleaning unit 15 scrapes and removes the toner remaining on the surface of the photosensitive member.

In this image forming apparatus, the photoconductor 2
When a so-called positive / positive developing method is used in which an electrostatic latent image on a photoconductor is visualized with toner having a different charging polarity from that of the above, the base of the photoconductor 2 is made of a conductor such as nickel. The C-shaped tubular member 1 is also made of a metallic conductor, and as shown in FIG. 1, the base of the photoconductor 2 is grounded by dropping it to the ground.
Positive development can be performed without any trouble. With such a simple configuration, such a developing method can be adopted without any problem.

When a negative / positive development (reversal development) method is used in which an electrostatic latent image on the photoconductor is visualized by a toner charged to the same polarity as the photoconductor 2, the photoconductor 2 It is generally practiced to apply a predetermined potential to the base body, but when applying this voltage application method to the embodiment shown in FIG. 1, for example, a predetermined voltage is applied to the conductive tubular member 1. This can be dealt with.

Here, the developing roller 6 for visualizing the electrostatic latent image formed on the photoconductor 2 is an example of the constitution of an image forming element which contacts a part of the photoconductor from the outside of the photoconductor. None, the opening 1A of the tubular member 1 gives tension to the photoconductor when the developing roller 6 is brought into contact with the photoconductor 2 at a predetermined pressure,
The photosensitive member portion 2A, which is in contact with the developing roller 6, serves as a photosensitive member escape portion that allows elastic movement inward of the cylindrical member. Such a photosensitive member escape portion is formed in a part of the cylindrical member 1. It is provided. The cylindrical member 1 is covered with the photosensitive member 2 in a play state, and the developing roller 6 is pressed against the portion 2A of the photosensitive member 2 to apply tension to the photosensitive member 2.

According to the present embodiment, the photosensitive member 2 is supported by the stationary cylindrical member 1 as compared with the conventional structure in which the belt photosensitive member is wound around and supported by a plurality of supporting rollers. Even if the life of the photoconductor is reached, only the belt photoconductor 2 needs to be replaced. A belt housing, a plurality of support rollers, drive gears, etc., which are attached to a unit belt photoconductor magazine, are attached and replaced. No need for parts In any case, the structure for supporting the photosensitive member can be greatly simplified, and the cost can be further reduced.

Further, it has become possible to adopt a contact developing system (a system in which a developing roller is brought into contact with a photosensitive member through a thin layer of toner to perform development), which has been difficult to combine with a drum-shaped photosensitive member. It is possible to obtain a high-density image with good fine line reproducibility. The photosensitive member and the developing roller as the image forming element can be brought into contact with each other in a more closely contacted state, and the advantages of the belt-shaped photosensitive member and the advantages of the low-cost drum-shaped photosensitive member can be utilized. .

It should be noted that the photosensitive member relief portion may be a recess 1C formed in the cylindrical member as shown in FIG. 2 instead of the opening formed in the cylindrical member, or the opening 1A (FIG. 1). ) Or an elastic member made of a soft material such as soft rubber or sponge, which is more easily deformed than the tubular member 1, is provided in the concave portion 1C, and the elastic member made of the above-described opening 1A is used as the photoreceptor escape portion. The same effect as the relief portion of the photoconductor can be obtained.

In the above-mentioned embodiment, the drive / charging roller 3 is used as a driving member for driving the photoconductor 2, but in addition to this, as shown in FIG. A photosensitive member driving member including the driving roller 17 may be used. As the charging means, for example, a dedicated scotrotron charging charger 18 is used.

Reference numeral 11 in the figure corresponds to the previous tubular member 1 (FIG. 1), and the tubular member 11 has an opening 11A which is a photoreceptor escape portion,
An endless belt-shaped photosensitive member 2 having flexibility is wound around the outer peripheral surface thereof.

Here, the tubular member 11 shown in FIG. 3 can also be made of a conductor such as metal, but this tubular member is made of an insulator such as an insulating resin having a small sliding friction. In addition, when a negative / positive developing method is adopted and a bias voltage is applied to the substrate of the photoconductor 2, the bias cannot be applied to the photoconductor via the tubular member 11. In this case, the driving roller 17 is connected to the photoconductor bias zener diode 19 with a core metal 17a.
And the conductive elastic roller 17b fixed to both ends in the longitudinal direction thereof, the drive roller 17 may be used as a bias terminal. That is, as shown by double hatching in FIG. 4, the belt-shaped photosensitive member 2 is configured such that the side edge portion of the belt-shaped photosensitive member 2 is exposed at the base 2a made of a conductor such as nickel, and the portion of the base 2a is exposed. First drive roller 1
The photosensitive member 2 is driven while the conductive elastic roller 17b of No. 7 is brought into pressure contact. The reference numeral 2b is an OPC photosensitive layer formed on the substrate. In this way, a bias voltage can be applied to the photoconductor 2 via the drive roller. Even when a negative / positive development method is adopted and a different potential (photoreceptor bias) must be applied to the conductive part (base) of the photoconductor in addition to the ground of the device electric circuit, it is easy to perform as described above. This can be dealt with.

Further, when the positive / positive developing system is adopted and the conductive substrate of the photoconductor 2 is grounded, the substrate 2a of the photoconductor 2 can be grounded via the drive roller 17 shown in FIG. it can.

In the case of the conventional belt-shaped photoreceptor, stainless steel, carbon, or the like is made into a brush shape, and this brush-shaped one is brought into contact with the conductive substrate of the belt-shaped photoreceptor. Occasionally, the photoconductor potential became abnormal. By driving the drive roller 17 functioning as a bias terminal under pressure as described above, such contact failure is less likely to occur, and the photosensitive member potential can be stabilized.

The other construction of the embodiment shown in FIG. 3 is the same as that of FIG. 1, and therefore its explanation is omitted.

By the way, in the example shown in FIG. 3, the driving roller 17 is used as a bias terminal. However, when such a driving roller 17 is not used or when the driving roller 17 is made of an insulating material, On the outer peripheral surface of the insulating tubular member 11 shown in FIG.
It is also possible to coat a material that is electrically conductive and has a low coefficient of sliding friction. The reference numeral 11F is the conductive coating layer. Then, the conductive coating layer 11F is used as a photoconductor bias terminal. For example, in order to insulate the tubular member 11 from the device ground, as shown in FIG.
One end of the tubular member 11 is fixed to the insulative main body substrate 23, and the other end is engaged with the protrusion 24a of the insulative main body front cover plate 24. In this way, a predetermined bias voltage is applied to the conductive base of the photoconductor 2 via the conductive coating layer 11F. In addition, this conductive coating layer 1
The base of the photoconductor 2 can be grounded via 1F.

In the embodiment shown in FIG. 5, a transfer roller 22 is used as the transfer means.
Can be brought into contact with and separated from the photoconductor 2. The other structure is the same as that of FIG. 1, and the roller 3 also uses a drive / charging roller as in FIG.

The conductive coating layer 11F shown in FIG. 6 can be formed by eutectoid plating of a metal such as nickel and Teflon resin, or a lubricant such as graphite can be applied. It can be formed in the same manner depending on the method. When the photoreceptor 2 having a nickel base is used, such a conductive coating layer 11F can be used particularly advantageously.

By the way, when the belt-shaped photoconductor is driven to rotate around the tubular member, the photoconductor may move in the axial direction of the tubular member. That is, it causes meandering. In order to prevent such meandering, to secure the stability of the belt photosensitive member when it is running, and at the same time, to obtain the convenience of its replacement, the following configuration can be adopted.

As shown in FIG. 8, a belt-shaped photosensitive member 2 having flexibility is wound around a cylindrical member 21 having a substantially cardioid shape. The concave portion 21A of the tubular member 21 is a photoreceptor relief portion, and its function is the same as that of the relief portion in the previous embodiment. Photosensitive member meandering prevention members 25 and 26 are arranged opposite to each other at the end of the tubular member 21,
The same thing is arranged opposite to the end on the back side.

FIG. 9 is a partial sectional view of the cylindrical member in the vicinity of the photoconductor meandering prevention member 25.
Prevents the photoconductor 2 from moving in the direction of the arrow b when the photoconductor 2 travels. The photoconductor meandering prevention member 25 on the opposite side (not shown) also prevents the photoconductor 2 from moving in the direction opposite to the arrow b direction. In any case,
The meandering of the belt-shaped photoreceptor 2 is prevented. The other photosensitive member meandering prevention member 26 (FIG. 8) has the same function.

The photoconductor meandering prevention member 25 shown in FIG. 9 is provided not on the photoconductor 2 but on the side of the image forming apparatus main body such as the end face of the tubular member 21 or its supporting frame. The prevention member 25 is rotatable around a pivot 27. For example, when the photoconductor 2 is to be removed in the direction of the arrow b when the photoconductor 2 is replaced, the photoconductor meandering prevention member 25 is rotated around the pivot 27 and placed at the broken line position. By doing so, the photoconductor meandering prevention member 25 is set to the photoconductor 2
It is placed in a position retracted from the removal path (which is also the removal path).

Further, the photosensitive member meandering prevention member 26 shown in FIG.
Is also provided on the image forming apparatus main body side in the same manner, and the pivot 2
8, the photosensitive member meandering prevention member 26 is rotated in the direction of the end surface of the tubular member 21.
Is placed at a position retracted from the removal path of the photoconductor 2.

Regarding the photoconductor meandering preventing members 25 and 26, either one may be used in a pair, or
You may use together. In any case, meandering of the belt-shaped photoconductor can be prevented, and the belt-shaped photoconductor can be easily replaced. The photoconductor meandering prevention member 25 may be configured such that the member 25 is biased to two positions of a meandering prevention position and a retracted position by an elastic member such as a central concealment spring.

As described above, at least one photosensitive member meandering preventing member 25, 26 for restricting the movement of the photosensitive member in the axial direction of the cylindrical member when the photosensitive member is rotationally driven is provided with an element other than the photosensitive member. And the photosensitive member meandering prevention member 25,
26 is operably supported at a position retracted from the attachment / detachment path of the photoconductor with respect to the tubular member when the photoconductor is replaced.

As the photosensitive member meandering preventing member, in addition to the above-described configuration example, a ring-shaped member slightly larger than the diameter of the cylindrical member 21 is used, and the ring-shaped member is attached to and detached from both ends of the cylindrical member 21. You may make it attach freely.

As mentioned at the beginning, in the conventional case,
In order to prevent the belt-shaped photoconductor from meandering, a belt-shaped step was formed on the back side of the photoconductor.However, if the photoconductor is configured in this way, the running cost of the photoconductor will increase and the user's burden will be high. Will be asked.

In the embodiments shown in FIGS. 8 and 9, the photosensitive member may be a simple belt member having no step on the back surface thereof, and it may be any member other than the photosensitive member for performing another function. It is not necessary and the cost burden on the user can be reduced as much as possible. The other configuration in FIG. 8 is
There is no difference from the embodiment shown in FIG.

FIG. 10 shows still another embodiment, in which the cylindrical member 31 around which the belt-shaped photosensitive member 2 is wound has recesses 31A and 31B on both sides which serve as the photosensitive member escape portions. An agitator 8 and an applicator (toner supply member) 9 are provided in the developing casing 37 of the developing unit 35, and the toner T is agitated and supplied to the developing roller 6 by these. The developing roller 6 is in contact with the photoconductor portion 2A located in the recess 31A with a predetermined pressure. Since the function of the developing roller 6 is as described above, the description thereof will be omitted here.

In the photoconductor portion 2B corresponding to the other concave portion 31B, the free end of the cleaning blade 46 provided in the cleaning unit 45 for cleaning the toner remaining on the photoconductor after the toner image transfer is provided with the predetermined end. Contact with pressure. Thus, in this example, a plurality of image forming elements 6, 4
6 are in contact with the photoconductor portions 2A and 2B from the outside, respectively. When these image forming elements 6 and 46 are brought into contact with the photoconductor 2, while applying tension to the photoconductor 2,
Photoreceptor escape portions, that is, concave portions 31A and 31B, which allow the photoconductor portions 2A and 2B in contact with the image forming elements 6 and 46 to move inward of the tubular member 31, are provided in a part of the tubular member 31. Is there.

By the way, when a belt-shaped photosensitive member supported by a plurality of supporting rollers is used as in the prior art, as for the cleaning blade, the cleaning blade is pressed against the photosensitive member portion where the supporting roller is present. There is. That is, the support roller serves as a backup body for the pressure contact portion of the cleaning blade.

In such a structure, elastic rubber is often used as the cleaning blade in the past. In other words, most of the structures in which rubber is pressed against a rigid body are adopted. However, in such a structure, uneven deformation of the rubber itself or unevenness of the outer peripheral surface of the support roller causes Due to the unevenness or the like of the cleaning blade, the edge portion of the cleaning blade is quickly worn or, in some cases, the edge portion is caught and the portion is damaged, and the life thereof is shortened.

On the other hand, in the embodiment shown in FIG.
Cleaning blade 46 made of elastic material such as rubber
Are brought into contact with the photoconductor portion 2B located in the recess 31B. As a result, the cleaning blade 46 comes into closer contact with the photoconductor 2, and the cleaning function of the residual toner by the cleaning blade 46 can be stably performed for a long period of time.

Further, as the cleaning blade 46 shown in FIG. 10, it is possible to use a blade made of a thin elastic plate as shown in the drawing. The cleaning blade 46 is pressed against the photoconductor 2 in the counter direction opposite to the rotation direction of the photoconductor 2. However, when the cleaning blade 46 made of such an elastic plate is used, the photoconductor surface is freely deformable. The shape of the cleaning blade tip follows, so even with a sharp metal blade,
This can be adopted as a cleaning means without any problem. By elastically bending and deforming the photoconductor portion 2B in this manner, it is possible to employ an elastic plate blade that is extremely excellent in toner removability.

On the other hand, when the other party is a rigid photoconductor (drum-shaped photoconductor) that is hard to allow deformation, it is difficult to use a thin elastic plate blade. It is possible to use plate blades. When an elastic plate blade made of metal or the like is used, unlike rubber, there is no deformation or chipping of the edge portion due to friction, and even spherical toner with a small particle size such as polymerized toner can be scraped off. can do.

In FIG. 10, the cleaning blade 46 made of a thin elastic plate is made of a magnetic material, and more specifically, for example, a soft magnet material (which is attracted to a magnet but is not used as a permanent magnet material, When the cleaning blade 46 is made of a ferromagnetic material having a small coercive force and is attracted by a magnetic force by a magnetic force generation source provided inside the tubular member 31, for example, an ordinary permanent magnet 29, The free end can be stably brought into close contact with the photoconductor 2.

That is, as shown in FIG. 11, the magnetic force lines 30 are concentrated on the free end portion of the cleaning blade 46, and the mutual attractive force between the belt-shaped photosensitive member 2 and the blade 46 is increased. It is possible to achieve good adhesion. As described above, in the embodiment shown in FIGS. 10 and 11, the image forming element is the cleaning blade 46 made of an elastic thin plate for scraping and removing the residual toner on the photoconductor. This blade 46 so that the edge portion is in close contact with the photoconductor 2.
A magnetic force generation source for attracting is generated inside the cylindrical member 31.

The photoreceptor 2 has an OPC photosensitive layer 2b formed on a substrate 2a. If the substrate 2a is made of a magnetic material such as nickel, the adhesion can be further improved. In addition, a better cleaning function can be stably performed over a long period of time.

In the embodiment shown in FIG. 10, since the cylindrical member 31 has a plurality of concave portions (31A, 31B),
When the belt-shaped photoconductor 2 is removed from the tubular member 31 after releasing the above-mentioned photoconductor meandering prevention member, this work can be performed easily. Other configurations in FIG. 10 are similar to those in FIG.
There is no difference from the embodiment shown in FIG.

By the way, in an image forming apparatus using a belt-shaped photoconductor, fine paper powder, dust, toner, abrasion powder of parts, etc., wrap around the back surface of the photoconductor and adhere to the back surface thereof. As a result, a streaky abnormal image is likely to occur on the photoconductor.

FIG. 12 shows an embodiment capable of removing such deposits.

In the figure, the tubular member 31 is partially provided with an opening 32 notched in the axial direction thereof. FIG. 13 is an enlarged cross-sectional view showing a tubular member portion in the vicinity of the opening. The wall portion 33 at the opening end along the axial direction has an edge on the outer peripheral surface side of the tubular member 31. Part 34
Are formed. The edge portion 34 removes the adhering matter that has wrapped around the back surface of the photoconductor 2.

On the other hand, without providing the edge portion 34,
A dedicated blade-shaped member (not shown) may be positioned in the opening 32, and its tip may be brought into contact with the back surface of the photoconductor 2 in the counter direction to scrape and remove the above-mentioned deposit. Good. The blade-shaped member used is preferably made of a metal having a sharp edge at its tip in order to minimize the frictional force with the photoconductor. The edge portion 34 and the blade-shaped member can be used together.

In any case, the back surface of the photoconductor 2 is cleaned by the photoconductor cleaning means composed of the edge portion 34, the blade-shaped member, or both.
This suppresses the generation of abnormal images. In addition, it is possible to prevent the deposits from intervening between the tubular member 31 and the photoconductor 2, so that the photoconductor 2 can rotate smoothly, or the outer peripheral surface of the tubular member 31 is damaged. Can be prevented. As described above, in the embodiments shown in FIGS. 12 and 13, the photosensitive member cleaning means for cleaning the back surface of the photosensitive member 2 is provided, and thereby the reliability of the apparatus is improved. The other configuration shown in FIG. 12 is substantially the same as that of the embodiment shown in FIG.

The removed and collected deposit may be stored in the tubular member 31 as it is, or the blade member or the edge portion may be twisted in the axial direction of the tubular member. Alternatively, the removed toner may be guided to the outside of the tubular member.

As described at the beginning, in the past, in order to prevent the meandering of the photoconductor, one of the back surfaces of the belt-shaped photoconductor is
For example, a belt-shaped step is formed on both side edges, and the end of the support roller is engaged with the edge of the step. It becomes impossible to scrape the toner removed from the outside of the cylindrical member. In this example, by using the above-described photosensitive member meandering preventing means, such a step portion is unnecessary, and the toner can be scraped to the outside of the tubular member.

The image forming element that contacts the photosensitive member portion of the cylindrical member facing the photosensitive member escape portion is not limited to the developing roller and the cleaning blade shown in each of the above-described embodiments, and for example, a photosensitive member may be used. It is also possible to select a charging member such as a charging roller for charging, a transfer member such as a transfer roller, and a charge removing member for removing charge from the photoconductor. Further, the present invention can be configured by appropriately combining the configurations of the above-described embodiments.

[0066]

According to the structure described in claim 1, the structure for supporting the photosensitive member can be further simplified and the cost can be further reduced, and the photosensitive member and the image-forming element can be mutually connected. It is possible to bring them into close contact with each other.

According to the second aspect of the invention, the photosensitive member and the developing roller can be brought into contact with each other in a more closely contacted state, and a high density image with good fine line reproducibility can be obtained. Then, such an improvement in image quality can be realized at a cost comparable to that of a drum-shaped photoreceptor.

According to the third aspect of the invention, a dedicated driving member is not required, the structure of the device can be simplified, and it is advantageous in terms of cost.

According to the structure described in claim 4, meandering of the photoconductor can be prevented, and the photoconductor can be easily attached to and detached from the tubular member. Further, it is not necessary to form a step or the like on the photoconductor to prevent meandering.

According to the fifth aspect of the present invention, the back surface of the photoconductor can be cleaned, and the occurrence of abnormal images due to the adhered matter on the back surface can be suppressed, and the photoconductor can be rotated. The reliability above can be improved.

According to the structure of claim 6, the free end portion of the cleaning blade can be brought into close contact with the photosensitive member, and a good cleaning function can be stably performed for a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional configuration diagram showing only a main part of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of another configuration example of a tubular member.

FIG. 3 is a schematic cross-sectional configuration diagram showing a main part of an image forming apparatus of another embodiment.

FIG. 4 is a configuration perspective view of a drive roller peripheral portion in the embodiment.

FIG. 5 is a schematic sectional configuration diagram showing a main part of an image forming apparatus according to still another embodiment.

FIG. 6 is a perspective view of a part of the tubular member in the above embodiment.

FIG. 7 is a cross-sectional view of a supporting component of a tubular member according to the above embodiment.

FIG. 8 is a schematic cross-sectional configuration diagram showing a main part of an image forming apparatus according to still another embodiment.

FIG. 9 is a partial cross-sectional view of a tubular member in the vicinity of the photoconductor meandering prevention member according to the embodiment.

FIG. 10 is a schematic cross-sectional configuration diagram showing a main part of an image forming apparatus according to still another embodiment.

FIG. 11 is an explanatory diagram showing a magnetic attraction state of the cleaning blade according to the embodiment.

FIG. 12 is a schematic cross-sectional configuration diagram showing a main part of an image forming apparatus according to still another embodiment.

FIG. 13 is a sectional view of the configuration of the back surface cleaning unit of the photoconductor according to the above embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 tubular member 2 photoconductor 2A photoconductor part 3 roller 6 developing roller 11 tubular member 21 tubular member 25 photoconductor meandering prevention member 26 photoconductor meandering prevention member 31 tubular member 46 cleaning blade

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03G 21/10 21/16 // G03G 15/08 502 F

Claims (6)

[Claims] 1. A tubular member that is held stationary with respect to the main body of the image forming apparatus, an endless belt-shaped photoconductor wound around the outer peripheral surface of the tubular member, and the photoconductor around the tubular member. And a driving member that is rotationally driven to, and an image forming element that comes into contact with a part of the photosensitive member from the outside of the photosensitive member. When the image forming element is brought into contact with the photosensitive member, while applying tension to the photosensitive member, An image forming apparatus comprising: a photosensitive member relief portion, which allows a photosensitive member portion in contact with an image forming element, to move inwardly of the cylindrical member. 2. The image forming apparatus according to claim 1, wherein the image forming element is a developing roller for visualizing an electrostatic latent image formed on a photoconductor. 3. The image forming apparatus according to claim 1, wherein the driving member is also used as a charging roller for the photosensitive member. 4. A photosensitive member meandering preventing member for restricting movement of the photosensitive member in the axial direction of the cylindrical member when the photosensitive member is rotationally driven is provided on an element other than the photosensitive member, and the photosensitive member meandering preventing member is provided. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is operably supported at a position retracted from the attachment / detachment path of the photoconductor with respect to the tubular member when the photoconductor is replaced. 5. The image forming apparatus according to claim 1, further comprising a photosensitive member cleaning unit that cleans a back surface of the photosensitive member. 6. The image forming element is a cleaning blade made of an elastic thin plate for scraping off and removing the residual toner on the photoconductor, and the edge portion of the cleaning blade is in close contact with the photoconductor. The image forming apparatus according to claim 1, wherein a magnetic force generation source that attracts the blade with a magnetic force is provided inside the cylindrical member.