JP2015079134A - Image formation unit and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress entrance of floating toner into a transportation path of a recording material.SOLUTION: An image formation module includes a development roll 53 for developing an electrostatic latent image formed on a photoreceptor drum 12 that rotates, a development housing 50 which contains a protruding part 51a that faces the photoreceptor drum 12 on a lower stream side in moving direction of the photoreceptor drum 12 when viewed from the development roll 53, and houses the photoreceptor drum 12, and a transportation chute 60 which faces the protruding part 51a on a lower stream side in moving direction of the photoreceptor drum 12 when viewed from the development housing 50, for guiding the recording material toward the photoreceptor drum 12. Between the protruding part 51a of the development housing 50 and the transportation chute 60, a flow passage is formed which guides the air current generated by rotation of the photoreceptor drum 12 in the direction coming away from the photoreceptor drum 12.

Description

  The present invention relates to an image forming unit and an image forming apparatus.

  As a conventional technique, there is a technique for maintaining a negative pressure in the developing device.

JP 2005-258275 A

  An object of the present invention is to suppress entry of floating toner into a recording material conveyance path.

According to a first aspect of the present invention, there is provided a developing member for developing the electrostatic latent image formed on the rotating image holding member, and the image holding member on the downstream side in the moving direction of the image holding member as viewed from the developing member. A housing member that accommodates the developing member; and is opposed to the end portion on the downstream side in the moving direction of the image carrier as viewed from the housing member, and the recording material is placed on the image carrier. A flow path for guiding an air flow generated by rotation of the image holding member in a direction away from the image holding member, between the end of the housing member and the guiding member. Is an image forming unit.
According to a second aspect of the present invention, the distance between the guide member and the end portion of the housing member is compared with the distance between the end portion and the image holding body and the distance between the guide member and the image holding body. 2. The image forming unit according to claim 1, wherein the image forming unit is formed in a large size.
The invention according to claim 3 is the image forming unit according to claim 1, wherein the guide member and / or the housing member is formed with a convex portion projecting toward the flow path.
According to a fourth aspect of the present invention, in the image forming unit according to the first aspect, the guide member is opposed to the image holding body in a vertically upward direction as compared with the end portion of the housing member. is there.
According to a fifth aspect of the present invention, there is provided a rotating image holding member, a developing member for developing an electrostatic latent image formed on the image holding member, and a downstream side in the moving direction of the image holding member as viewed from the developing member. A recording member having an end portion facing the image carrier, a housing member for housing the developing member, and facing the end portion on the downstream side in the moving direction of the image carrier as viewed from the housing member. A guide member that guides the image carrier toward the image carrier, and an air flow generated by the rotation of the image carrier between the end of the housing member and the guide member. An image forming apparatus is characterized in that a flow path leading to a direction away is formed.
In the invention according to claim 6, the distance between the guide member and the end portion of the housing member is compared with the distance between the end portion and the image holding body and the distance between the guide member and the image holding body. The image forming apparatus according to claim 5, wherein the image forming apparatus is large.
The invention according to claim 7 further includes a wind generating means for generating a wind for guiding the air flow generated by the rotation of the image holding body in a direction away from the image holding body through the flow path. The image forming apparatus according to claim 5.

According to the first aspect of the present invention, it is possible to prevent the floating toner from entering the recording material conveyance path as compared with the case where this configuration is not provided.
According to the second aspect of the present invention, it becomes easier to guide the floating toner in the direction away from the image holding member as compared with the case where the present configuration is not provided.
According to the third aspect of the present invention, it is possible to suppress the toner falling to the outside of the image forming unit as compared with the case where this configuration is not provided.
According to the fourth aspect of the present invention, it is possible to further suppress the floating toner from entering the recording material conveyance path as compared with the case where this configuration is not provided.
According to the fifth aspect of the present invention, it is possible to prevent the floating toner from entering the recording material conveyance path as compared with the case without this configuration.
According to the sixth aspect of the present invention, it becomes easier to guide the floating toner in a direction away from the image holding member as compared with the case where this configuration is not provided.
According to the seventh aspect of the present invention, it is easier to guide the floating toner in a direction away from the image holding member as compared with the case where this configuration is not provided.

1 is a diagram illustrating an example of a configuration of an image forming apparatus to which the exemplary embodiment is applied. It is a figure showing an example of composition of an image forming part to which this embodiment is applied. FIG. 4 is a diagram illustrating a positional relationship among a developing housing, a conveyance chute, and a photosensitive drum in an image forming module. It is a figure for demonstrating the flow of the airflow around the photoconductive drum of this Embodiment.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating an example of a configuration of an image forming apparatus 1 to which the exemplary embodiment is applied. An image forming apparatus 1 shown in FIG. 1 is a single-color printer, an image forming unit 10 that forms an image corresponding to image data, and a user interface (UI) 4 that receives instructions from the user and displays messages to the user. An image that is connected to an external device such as a personal computer (PC) 2 or an image reading device 3 for controlling the operation of the entire image forming apparatus 1 and performs image processing on image data received from these devices. A processing unit 6 is provided.
The image forming apparatus 1 also includes a recording material supply unit 40 that supplies a recording material to the image forming unit 10 and a toner cartridge 45 that supplies toner to the image forming unit 10.

FIG. 2 is a diagram illustrating an example of the configuration of the image forming unit 10 to which the exemplary embodiment is applied.
As shown in FIG. 2, the image forming unit 10 includes a photosensitive drum 12 as an example of an image carrier that is rotatably provided and forms an electrostatic latent image and holds a toner image, and the surface of the photosensitive drum 12. The charging device 13 for charging, the exposure device 14 for exposing the photosensitive drum 12 charged by the charging device 13 based on the image data (see FIG. 1), and developing the electrostatic latent image formed on the photosensitive drum 12 A developing unit 15 and a cleaner 16 for cleaning the surface of the photosensitive drum 12 after transfer are provided. Note that the photosensitive drum 12 in the present exemplary embodiment includes a rotation shaft (not shown) so that the axial direction is directed from the front side (front side in the figure) to the rear side (back side in the figure) of the image forming apparatus 1. Is arranged.

Further, the image forming unit 10 forms a transfer unit with the photosensitive drum 12, and transfers a toner image formed on the photosensitive drum 12 to a recording material, and records the transferred toner image. A fixing device 30 for fixing on the material is provided.
Further, the image forming unit 10 includes a peeling member 17 that peels the recording material onto which the toner image has been transferred by the transfer roll 20 from the surface of the photosensitive drum 12.
Furthermore, the image forming unit 10 is an example of a conveyance roll 47 that conveys the recording material toward the transfer unit (transfer roll 20), and a guide member that conveys and guides the recording material conveyed by the conveyance roll 47 to the transfer unit. The conveyance chute 60 is provided.

  In the image forming unit 10 of the present embodiment, the photosensitive drum 12, the charger 13, the developing device 15, the cleaner 16, the peeling member 17, and the conveyance chute 60 are configured as an integrated image forming module 100. The image forming module 100 is an example of an image forming unit, is configured to be detachable from the image forming apparatus 1 (see FIG. 1), and is exchanged according to the life of the photosensitive drum 12 or the like.

The charger 13 of the present embodiment has a charging roll 13a that comes into contact with the surface of the photosensitive drum 12, and a contact charging system that charges the surface of the photosensitive drum 12 by applying a voltage to the charging roll 13a. Is adopted. In the charger 13 of the present embodiment, the surface of the photosensitive drum 12 is charged negatively by the charging roll 13a.
Here, as a method of applying a voltage to the charging member for charging the photosensitive drum 12, generally, a DC method in which only a DC voltage is applied and an AC superposition in which an AC voltage is superimposed on the DC voltage are applied. System. In the present embodiment, a direct current method in which only a direct current voltage is applied to the charging roll 13a is adopted.

  Further, the exposure device 14 irradiates the surface of the photosensitive drum 12 with laser light, for example, and exposes the photosensitive drum 12 charged by the charger 13. Specifically, the exposure device 14 selectively lowers the surface potential of the photoconductive drum 12 by selectively exposing the surface of the photoconductive drum 12 charged to a negative polarity by a charger. An electrostatic latent image is formed on the surface of the drum 12.

  Subsequently, as shown in FIG. 2, the developing device 15 of the present embodiment holds a developing housing 50 as an example of a housing member in which a developer containing toner and a carrier is contained, and holds the developer. A developing roll 53 as an example of a developing member that develops the electrostatic latent image on the photoconductive drum 12 with a developer, is disposed in the developing housing 50 in parallel with the axial direction of the photosensitive drum 12, and the developer is applied to the developing roll 53. A pair of screw augers 54 and 55 are provided.

  The development housing 50 has an opening toward the photosensitive drum 12 side. Further, the developer housing 50 contains a developer containing, for example, negatively charged toner and a carrier that is magnetic particles, a developer containing portion 52 in which screw augers 54 and 55 are arranged, and a developer. An extending portion 51 is formed which extends from the housing portion 52 toward the opening on the photosensitive drum 12 side and in which the developing roll 53 is disposed. Although details will be described later, the extending portion 51 of the developing housing 50 extends upward from the developer accommodating portion 52 in the vertical direction. The extending portion 51 includes a surface that faces the surface of the photosensitive drum 12 via a predetermined gap and a surface that faces the conveyance chute 60 via a predetermined gap.

  The developing roll 53 is provided so as to face the photosensitive drum 12 through the opening of the developing housing 50, and is driven to rotate in the direction of arrow C by a driving unit (not shown). In the present embodiment, the developing roller 53 is rotationally driven by a driving unit (not shown) so that the linear velocity on the surface of the developing roller 53 is higher than the linear velocity on the surface of the photosensitive drum 12.

  The developing roll 53 is applied with a developing bias composed of a DC voltage by a power source (not shown) or a developing bias in which an AC voltage is superimposed on the DC voltage, and forms a developing electric field between the developing roller 53 and the photosensitive drum 12. As a result, the electrostatic latent image formed on the surface of the photosensitive drum 12 is developed with the toner.

Subsequently, the conveyance chute 60 is provided along a surface extending in the rotation axis direction of the photosensitive drum 12 and facing the extending portion 51 of the developing housing 50 with a gap. In this example, the conveyance chute 60 is disposed along the vertical direction. In the present embodiment, the conveyance chute 60 is formed integrally with the developing housing 50.
In the conveyance chute 60 of the present embodiment, a convex portion 61 that protrudes toward the extending portion 51 is formed on the side facing the developing housing 50. The function and the like of the convex portion 61 will be described later.

Further, the conveyance chute 60 guides the recording material conveyed by the conveyance roll 47 to the transfer unit on the surface opposite to the side facing the extending portion 51 of the developing housing 50.
In the following description, the surface of the conveyance chute 60 that faces the extending portion 51 of the developing housing 50 is referred to as an inner wall surface 60 a of the conveying chute 60, and the extending portion of the developing housing 50 among the conveying chute 60. The surface opposite to the surface facing 51 may be referred to as the outer wall surface 60 b of the conveyance chute 60.

Next, the configuration of the developing housing 50 (particularly the extending portion 51) and the conveyance chute 60 of this embodiment, the positional relationship between the developing housing 50, the conveyance chute 60, and the photosensitive drum 12 will be described in detail.
FIG. 3 is a diagram showing the positional relationship between the developing housing 50, the conveyance chute 60, and the photosensitive drum 12 in the image forming module 100.

As shown in FIG. 3, a protruding portion 51 a that protrudes upward in the vertical direction toward the photosensitive drum 12 is formed at the upper end portion of the extending portion 51 of the developing housing 50. In the present embodiment, the protruding portion 51a formed in the extending portion 51 faces the photosensitive drum 12, and a gap (first gap G1) is formed between the protruding portion 51a and the surface of the photosensitive drum 12. ) Is formed. The width of the first gap G1 (that is, the shortest distance between the surface of the protrusion 51a facing the photosensitive drum 12 and the surface of the photosensitive drum 12) is the first length d1.
In the present embodiment, the protrusion 51a of the developing housing 50 corresponds to the end of the housing member.

Further, as described above, the conveyance chute 60 is provided along the vertical direction. As shown in FIG. 3, the inner wall surface 60a of the transport chute 60 is opposed to the protruding portion 51a of the extending portion 51 of the developing housing 50 through the gap (second gap G2), and has an upper end in the vertical direction. It faces the photosensitive drum 12 via a gap (third gap G3).
In the present embodiment, the width of the second gap G2 (the shortest distance between the inner wall surface 60a of the transport chute 60 and the surface of the protrusion 51a facing the transport chute 60) is the second length d2. Yes. Further, the width of the third gap G3 (the shortest distance between the upper end portion of the transport chute 60 and the surface of the photosensitive drum 12) is the third length d3.

Here, the second length d2 is set to be longer than the first length d1 and the third length d3 (d2> d1, d2> d3). In this example, d1 = 1 mm, d2 = 3 mm, and d3 = 1.4 mm.
Thus, in the present embodiment, the area per unit length of the first gap G1, the second gap G2, and the third gap G3 along the rotation axis direction of the photosensitive drum 12 is the second gap G2> the second gap G2. The relationship is 1 gap G1, 2nd gap G2> 3rd gap G3.

Furthermore, in the present embodiment, as shown in FIG. 3, the upper end portion of the conveyance chute 60 facing the photosensitive drum 12 is vertical compared to the protruding portion 51 a formed in the extending portion 51 of the developing housing 50. Located in the upper direction.
Further, a tangent line of the photosensitive drum 12 in a region facing the protruding portion 51a of the developing housing 50 through the first gap G1 is defined as a first straight line, a straight line passing through the upper end of the protruding portion 51a and parallel to the first straight line. Is the second straight line, in the present embodiment, the upper end of the transport chute 60 is located in a region between the first straight line and the second straight line.

  Further, as described above, the convex portion 61 is formed on the inner wall surface 60 a of the conveyance chute 60 so as to protrude toward the extended portion 51 of the developing housing 50. As shown in FIG. 3, the convex portion 61 formed on the conveyance chute 60 is located below the portion of the second gap G2 facing the photosensitive drum 12 in the vertical direction. That is, the convex portion 61 is provided so as to face the photosensitive drum 12 with the second gap G2.

Further, the second gap G2 formed between the extending portion 51 of the developing housing 50 and the inner wall surface 60a of the conveyance chute 60 is provided on the image forming module 100 (see FIG. 2) from the side facing the photosensitive drum 12. It is provided so as to penetrate toward the outside. Thereby, for example, when the airflow enters from the side facing the photosensitive drum 12 with respect to the second gap G2, the airflow passes through the second gap G2 and escapes to the opposite side.
In other words, in the present embodiment, a flow path through which airflow can pass is formed by the second gap G <b> 2 between the extended portion 51 of the developing housing 50 and the inner wall surface 60 a of the transport chute 60.

  By the way, in the image forming unit 10 of the present embodiment, as described above, when developing the electrostatic latent image formed on the surface of the photosensitive drum 12, the cloud that is the toner floating from the developing device 15 is used. Toner (toner cloud) may be generated.

That is, in the developing device 15, the toner rises in the developing housing 50 of the developing device 15 by stirring the toner by the screw augers 54 and 55, supplying new toner into the developing device 15, and the like. Cloud toner may occur.
Here, in the developing device 15, for example, when the screw augers 54 and 55 and the developing roll 53 rotate, an air flow flowing into the developing housing 50 is generated. As a result, the inside of the developing housing 50 is at a higher pressure than the outside of the developing housing 50. As a result, in the developing device 15, air leaks from the inside of the developing housing 50, and the cloud toner generated in the developing housing 50 may leak from the developing housing 50 and drift around the developing device 15.

  Further, as described above, in the present embodiment, the developing roll 53 and the photosensitive drum 12 are rotationally driven so that the linear velocity on the surface of the developing roller 53 is higher than the linear velocity on the surface of the photosensitive drum 12. Has been. Therefore, around the developing device 15 of the present embodiment, the toner particles are likely to be scattered and the cloud toner is likely to be generated due to the speed difference between the surface of the developing roll 53 and the surface of the photosensitive drum 12.

Furthermore, in this embodiment, both the surface potential of the photosensitive drum 12 and the toner potential of the developer are negative. For this reason, the toner repels the surface of the photosensitive drum 12 around the developing device 15 of the present embodiment, so that the toner particles are easily scattered and the cloud toner is easily generated.
Furthermore, in the developing device 15, when the developing roll 53 is charged by superimposing an AC voltage on a DC voltage, the toner particles tend to scatter more easily than when the developing roll 53 is charged only by the DC voltage. There is.

When the cloud toner leaks around the developing device 15 and further reaches the recording material conveyance path beyond the conveyance chute 60, the toner may adhere to the recording material and the recording material may become dirty.
Specifically, the recording material conveyed by the conveyance roll 47 (see FIG. 1) is guided to the transfer roll 20 (see FIG. 2) by the outer wall surface 60b of the conveyance chute 60. At this time, since the recording material is guided while rubbing the outer wall surface 60b of the conveyance chute 60, the outer wall surface 60b of the conveyance chute 60 is charged by friction with the recording material, and the toner is easily attached.

When the toner adheres to and accumulates on the outer wall surface 60 b of the conveyance chute 60, the recording material is guided by the conveyance chute 60, so that the recording material rubs the toner accumulated on the outer wall surface 60 b of the conveyance chute 60. In some cases, toner may adhere to the recording material. As a result, the recording material may be soiled.
Further, when the toner adheres to the outer wall surface 60b of the transport chute 60, when the image forming module 100 (see FIG. 2) is replaced with the image forming apparatus 1 (see FIG. 1), the transport chute 60 There is a possibility that the toner adhering to the outer wall surface 60b may fall into the image forming apparatus 1, or the toner may adhere to the hand of an operator who replaces the image forming module 100.

  In contrast, in the present embodiment, as described above, the positional relationship among the developing housing 50, the conveyance chute 60, and the photosensitive drum 12 is set, so that the airflow including the cloud toner flows in the recording material conveyance path. Thus, the toner is prevented from adhering to the recording material or the outer wall surface 60b of the conveyance chute 60 that guides the recording material.

  Next, the flow of airflow including cloud toner around the photosensitive drum 12 will be described. FIG. 4 is a diagram for explaining the flow of airflow around the photosensitive drum 12 of the present embodiment.

When the image forming unit 10 (see FIG. 1) forms an image, the photosensitive drum 12 rotates in the direction of arrow A. In the developing device 15, the developing roll 53 rotates in the direction of arrow C.
Along with this, an air flow according to the rotation of the photosensitive drum 12 and the developing roll 53 is generated around the photosensitive drum 12 and the developing roll 53. Specifically, an air flow is generated around the photosensitive drum 12 and the developing roll 53 in the moving direction of the photosensitive drum 12 along the surface of the photosensitive drum 12 as indicated by an arrow E1.
Then, the cloud toner generated in the developing housing 50 of the developing device 15 is discharged from the first gap G1 to the outside of the developing housing 50 by the air flow indicated by the arrow E1.

  In the present embodiment, the width (first length d1) of the first gap G1 formed between the protruding portion 51a of the extending portion 51 of the developing housing 50 and the surface of the photosensitive drum 12 is set to be the first. 2 is set smaller than the width of the gap G2 (second length d2). As a result, the cloud toner generated in the developing housing 50 is blocked by the protruding portion 51a, so that the developing from the first gap G1 is performed as compared with the case where the first length d1 is larger than the second length d2, for example. The amount of cloud toner discharged outside the housing 50 is reduced.

Subsequently, the airflow including the cloud toner discharged from the first gap G1 proceeds along the moving direction of the photosensitive drum 12.
In the present embodiment, a second gap G2 is formed between the extending portion 51 of the developing housing 50 and the inner wall surface 60a of the transport chute 60 on the downstream side of the first gap G1 in the moving direction of the photosensitive drum 12. Has been. Further, a third gap G3 is formed between the conveyance chute 60 and the surface of the photosensitive drum 12 on the downstream side in the moving direction of the photosensitive drum 12 with respect to the first gap G1 and the second gap G2.
For this reason, the airflow discharged from the first gap G1 and traveling along the direction of movement of the photosensitive drum 12 is normally directed to the third gap G3 side as indicated by the arrow E3 and second as indicated by the arrow E2. Branches toward the gap G2.

In the present embodiment, as described above, the width of the second gap G2 (second length d2; see FIG. 3) is equal to the width of the third gap G3 (third length d3; see FIG. 3). It is set large compared. As a result, in the present embodiment, the flow path area of the second gap G2 is larger than the flow path area of the third gap G3, and the flow resistance when the airflow proceeds to the second gap G2 is increased. This is smaller than the flow path resistance when the air flow proceeds to the third gap G3.
For this reason, most of the airflow discharged from the first gap G1 travels to the second gap G2, and entry into the third gap G3 is suppressed.

As a result, in the present embodiment, the cloud toner discharged from the developing device 15 via the first gap G1 advances to the second gap G2, as indicated by the arrow E2, and the third gap G3 passes through the third gap G3. The entry into the recording material conveyance path positioned on the outer wall surface 60b side of the conveyance chute 60 is suppressed.
As a result, it is possible to suppress the toner from adhering to the outer wall surface 60 b of the conveyance chute 60. Then, it is possible to suppress the toner from adhering to the recording material conveyed by the conveying chute 60 and to prevent the recording material from being contaminated.

Here, in the present embodiment, as described above, the upper end portion of the conveyance chute 60 is positioned upward in the vertical direction as compared with the protruding portion 51 a formed in the extending portion 51 of the developing housing 50. . Thereby, for example, compared with the case where the upper end portion of the transport chute 60 is positioned below the protrusion 51 a in the vertical direction, the air flow including the cloud toner discharged from the first gap G <b> 1 hits the inner wall surface 60 a of the transport chute 60. It becomes easy.
As a result, compared to the case where this configuration is not adopted, the airflow including cloud toner can easily change the traveling direction toward the second gap G2, and the cloud toner leaks into the recording material conveyance path or the conveyance chute 60 It is possible to further suppress the toner from adhering to the outer wall surface 60b.

Subsequently, the airflow that has traveled to the second gap G2 travels downward in the figure through the second gap G2, as indicated by an arrow E4.
In the present embodiment, as described above, the convex portion 61 is formed on the inner wall surface of the conveyance chute 60. As a result, when the airflow passes through the second gap G2, the toner contained in the airflow adheres to and accumulates on the surface of the convex portion 61.
Here, as described above, the convex portion 61 is provided so as to be positioned vertically below the portion of the second gap G2 that faces the photosensitive drum 12 (that is, the portion into which the air current containing cloud toner enters). ing. Thereby, when the toner contained in the airflow that has entered the second gap G2 falls due to gravity, the toner easily adheres to the convex portion 61.

  Further, the air flow including the remaining toner that has not adhered to the convex portion 61 travels further downward in the second gap G2. Here, as described above, since the second gap G2 is provided through the image forming module 100, the airflow is discharged to the outside of the image forming module 100 at a position away from the recording material conveyance path. As a result, the remaining toner included in the airflow is also discharged to the outside of the image forming module 100.

By the way, in the present embodiment, the conveyance chute 60 is formed integrally with the developing housing 50 and is configured as a part of the image forming module 100 together with the developing housing 50. Thus, for example, when the image forming module 100 is removed from the image forming apparatus 1 when replacing the image forming module 100, the transport chute 60 is removed from the image forming apparatus 1 together with the developing housing 50.
Thereby, along with the replacement of the image forming module 100, it is possible to remove the toner adhering to the convex portion 61 of the conveyance chute 60, the inner wall surface 60 a of the conveyance chute 60 and the like from the image forming apparatus 1.

In particular, in the present embodiment, the toner is prevented from adhering to the outer wall surface 60b of the conveyance chute 60 exposed to the outside in the image forming module 100. On the other hand, the convex portion 61 of the conveyance chute 60 and the inner wall surface 60a of the conveyance chute 60 that the toner is likely to adhere to are not exposed to the outside in the image forming module 100.
Thus, when the image forming module 100 is exchanged, it is possible to prevent the toner from adhering to the operator's hand or the like and the toner from falling into the image forming apparatus 1.

  Here, in the second gap G2, an airflow flows from the upper side to the lower side in the drawing, and therefore, the toner tends to adhere to the convex portion 61 of the conveying chute 60 on the upper surface in the drawing. In the present embodiment, when the image forming module 100 is removed from the image forming apparatus 1, the convex portion 61 is provided so that the surface of the convex portion 61 where the toner easily adheres does not face downward. Thereby, the toner adhering to the convex portion 61 is suppressed from falling into the image forming apparatus 1.

  In the present embodiment, the convex portion 61 is provided on the inner wall surface of the transport chute 60 in order to adhere the cloud toner that has entered the second gap G2. However, for example, a protruding portion that protrudes toward the conveyance chute 60 side may be provided in a portion of the extended portion 51 of the developing housing 50 that faces the second gap G2, and the extended portion 51 of the developing housing 50 Convex portions may be provided on both the conveyance chute 60.

Further, in order to further suppress the cloud toner generated in the developing unit 15 or the like from reaching the recording material conveyance path, intake air or air blowing is performed so that an air flow from the photosensitive drum 12 toward the second gap G2 is generated. A fan (wind generating means) may be provided. As a result, the airflow including the cloud toner easily proceeds to the second gap G2 side, and the cloud toner enters the outer wall surface 60b side of the conveyance chute 60 and further suppresses the toner from adhering to the recording material or the like. Can do.
Here, in the image forming apparatus 1, for example, a fan (not shown) for generating cooling air may be provided in order to cool a power supply device (not shown), a fixing device 30 (see FIG. 1), or the like. However, this fan may be used to generate an air flow that goes from the photosensitive drum 12 toward the second gap G2.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 10 ... Image forming part, 12 ... Photosensitive drum, 15 ... Developing device, 50 ... Developing housing, 51 ... Extension part, 53 ... Developing roll, 60 ... Conveying chute, 61 ... Convex part, 100 ... Image forming module

Claims (7)

A developing member for developing the electrostatic latent image formed on the rotating image carrier;
A housing member that has an end facing the image carrier on the downstream side in the moving direction of the image carrier as seen from the developing member, and houses the developing member;
A guide member that opposes the end portion on the downstream side in the moving direction of the image carrier as viewed from the housing member and guides the recording material toward the image carrier;
An image forming system is characterized in that a flow path is formed between the end of the housing member and the guide member to guide an air flow generated by the rotation of the image holding member in a direction away from the image holding member. unit.   The distance between the guide member and the end of the housing member is formed larger than the distance between the end and the image carrier and the distance between the guide member and the image carrier. The image forming unit according to claim 1.   The image forming unit according to claim 1, wherein the guide member and / or the housing member is formed with a convex portion that protrudes toward the flow path.   2. The image forming unit according to claim 1, wherein the guide member is opposed to the image holding member in a vertically upward direction as compared with the end portion of the housing member. A rotating image carrier;
A developing member for developing the electrostatic latent image formed on the image carrier;
A housing member that has an end facing the image carrier on the downstream side in the moving direction of the image carrier as seen from the developing member, and houses the developing member;
A guide member that opposes the end portion on the downstream side in the moving direction of the image carrier as viewed from the housing member and guides the recording material toward the image carrier;
An image forming system is characterized in that a flow path is formed between the end of the housing member and the guide member to guide an air flow generated by the rotation of the image holding member in a direction away from the image holding member. apparatus.   The distance between the guide member and the end of the housing member is formed larger than the distance between the end and the image carrier and the distance between the guide member and the image carrier. The image forming apparatus according to claim 5, wherein:   6. The image according to claim 5, further comprising wind generating means for generating a wind for guiding an air flow generated by the rotation of the image holding body in a direction away from the image holding body through the flow path. Forming equipment.

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