JP2021176011A - Image forming apparatus - Google Patents

Abstract

To provide a configuration that conveys a scattered toner with an airflow in an airflow space and recovers the toner from an opening in a developer container, and prevent an increase in size of a device when a fan for sucking in air through the opening is arranged.SOLUTION: An airflow space part 52 is an air channel that is arranged on a side (front side) of a developer container 41 facing a photoconductor drum for recovering a toner scattered from a developing sleeve 44a. A duct 53 is a duct that is connected with the airflow space part 52 so as to allow an airflow to circulate between the airflow space part 52 and the duct, arranged below a one end side (depth side) in a rotation axis direction of the developing sleeve 44a and the developer container 41, and formed from a front side up to the opposite side (back side) of a side of the developer container 41 facing the photoconductor drum. A suction fan is arranged on the back side and the depth side and sucks in air from an opening in the duct to generate an airflow in the airflow space part 52.SELECTED DRAWING: Figure 9

Description

The present invention relates to an image forming apparatus including a developing apparatus for developing an electrostatic latent image formed on an image carrier using a developer containing toner and a carrier.

The image forming apparatus includes a developing apparatus that develops an electrostatic latent image formed on a photosensitive drum (image carrier) with a developer containing toner and a carrier. In such a developing apparatus, an image is formed by supporting the developing agent contained in the developing container on a developing sleeve (developing rotating body) and transporting the developer to a region facing the photosensitive drum. At this time, toner scattered from the developing sleeve or the like into the space between the developing container and the photosensitive drum (hereinafter referred to as scattered toner) may leak from the inside of the developing container to the outside and contaminate the inside of the apparatus.

The image forming apparatus of Patent Document 1 includes a developing apparatus having a toner receiving portion for receiving scattered toner. Further, in this image forming apparatus, below the developing sleeve, a flow path (airflow space) through which airflow can flow between the developing container, the photosensitive drum, and the toner receiving portion is in the direction of the rotation axis of the photosensitive drum (rotation of the developing sleeve). It is formed along the axial direction). Then, in this image forming apparatus, an opening in which air is sucked by the fan is provided in the developing container, and the fan sucks air through the opening, so that the rotation axis of the photosensitive drum is in the airflow space. Airflow is generated along the direction. In this way, in the configuration of Patent Document 1, the scattered toner is conveyed by the air flow in the airflow space and collected from the opening of the developing container.

Japanese Unexamined Patent Publication No. 2011-191522

On the other hand, inside the apparatus, a driving force such as a gear or a coupling for transmitting the driving force for rotationally driving the developing sleeve to the developing sleeve is transmitted to one end side in the longitudinal direction of the developing apparatus (the direction of the rotation axis of the developing sleeve). A member and a driving device such as a motor that applies a driving force to the driving force transmitting member are provided.

Therefore, as in Patent Document 1, in a configuration in which the scattered toner is conveyed by the air flow in the airflow space and collected from the opening of the developing container, the same side as the side where the driving force transmitting member and the driving device are arranged. When forming an airflow space in the device, a space for arranging a fan for sucking air through the opening must be secured inside the device so that the driving force transmitting member and the driving device do not interfere with each other. Therefore, there is a risk that the device will become large.

According to the present invention, in a configuration in which scattered toner is conveyed by an air flow in an airflow space and collected from an opening of a developing container, when a fan for sucking air is arranged through the opening, the apparatus can be used. It is an object of the present invention to provide an image forming apparatus capable of suppressing an increase in size.

The image forming apparatus of the present invention includes an image carrier, an exposure apparatus that exposes the image carrier to form an electrostatic latent image on the image carrier, and a developing container containing a developer containing toner and a carrier. A developing rotating body that carries and conveys the developer to a developing position for developing an electrostatic latent image formed on the image carrier, a side of the developing container facing the image carrier, and the developing rotation. A developing apparatus having a driving force transmitting member arranged on one end side in the direction of the rotation axis of the body and transmitting a driving force for rotationally driving the developing rotating body to the developing rotating body, and the image of the developing container. A drive device arranged on the side facing the carrier and one end side in the direction of the rotation axis of the developing rotary body to apply the driving force to the driving force transmitting member, and facing the image carrier of the developing container. An airflow space portion which is an air flow path for collecting toner scattered from the developing rotating body, which is arranged on the developing side and is formed from one end side to the other end side in the direction of the rotating axis of the developing rotating body. And, it is arranged on one end side of the developing rotating body in the direction of the rotation axis and on the lower side of the developing container, and faces the image carrier of the developing container from the side of the developing container facing the image carrier. The duct connected to the airflow space so that the airflow can flow between the airflow space and the airflow space formed on the side opposite to the side is opposite to the side of the developing container facing the image carrier. A suction fan is provided on the side and one end side of the developing rotating body in the direction of the rotation axis, and for sucking air from the opening of the duct in order to generate airflow in the airflow space. It is a feature.

According to the present invention, in a configuration in which scattered toner is conveyed by an air flow in an airflow space and collected from an opening of a developing container, when a fan for sucking air through the opening is arranged. It is possible to prevent the device from becoming large.

The schematic block sectional view of the image forming apparatus which concerns on 1st Embodiment. The schematic configuration perspective view of the developing apparatus which concerns on 1st Embodiment. FIG. 2 is a cross-sectional view taken along the broken line A in FIG. FIG. 2 is a cross-sectional view of the vicinity of the closest position between the developing sleeve and the photosensitive drum in the broken line A of FIG. FIG. 2 is a cross-sectional view of the vicinity of the closest position between the developing sleeve and the photosensitive drum in the broken line B of FIG. The figure which cut a part and looked at from the right back side of FIG. A perspective view of the developing apparatus according to the first embodiment as viewed from the cooling duct side. A perspective view of a part of the developing apparatus according to the first embodiment as viewed from the developing sleeve side. The perspective view which shows the flow of the air flow in the developing apparatus which concerns on 1st Embodiment. The plan view around the discharge part of the developing apparatus which concerns on 1st Embodiment. The perspective view of the connection part of the exhaust duct with the developing apparatus which concerns on 1st Embodiment. The figure which shows the relationship between the intake port of the exhaust duct which concerns on 1st Embodiment, and the discharge port of a developing apparatus. The figure which shows how the airflow pushed into a cooling duct flows back to the connection duct side. The plan view around the discharge part of the developing apparatus which concerns on 2nd Embodiment. The figure which shows the relationship between the intake port of the exhaust duct which concerns on 2nd Embodiment, and the 1st and 2nd discharge ports of a developing apparatus. The block diagram concerning the output control of the suction fan and the cooling fan which concerns on 3rd Embodiment. (A) A graph showing the relationship between the toner charge amount (Q / M) and the scattered toner amount, and (b) a graph showing the relationship between the humidity and the toner charge amount (Q / M). The table which shows the environment table of the fan control which concerns on 3rd Embodiment. The flowchart of the fan control which concerns on 3rd Embodiment.

<First Embodiment>
The first embodiment will be described with reference to FIGS. 1 to 12. First, the schematic configuration of the image forming apparatus of this embodiment will be described with reference to FIG.

[Image forming device]
The image forming apparatus 100 is a so-called tandem in which image forming portions Y, M, C, and K for forming toner images of four colors of yellow, magenta, cyan, and black are provided along the rotation direction of the intermediate transfer belt 62. This is the configuration of the method. The image forming apparatus 100 produces a toner image (image) according to an image signal from a document reading device (not shown) connected to the apparatus main body or a host device such as a personal computer communicatively connected to the apparatus main body. Form on recording material. Examples of the recording material include sheet materials such as paper, plastic film, and cloth.

The four image forming units Y, M, C, and K included in the image forming apparatus 100 have substantially the same configuration except that the developed colors are different. Therefore, the image forming unit Y will be described below as a representative, and the description of the other image forming units will be omitted.

A cylindrical photoconductor, that is, a photosensitive drum 1A, is arranged as an image carrier in the image forming portion Y. The photosensitive drum 1A is rotationally driven in the direction of the arrow in the figure. A charging roller 2A (charging device), a developing device 4A, a primary transfer roller 61A, and a cleaning device 8A are arranged around the photosensitive drum 1A. A laser scanner (exposure apparatus) 3A is arranged above the photosensitive drum 1A in the drawing.

Further, an intermediate transfer belt 62 as an intermediate transfer body is arranged so as to face the photosensitive drums 1A, 1B, 1C, and 1D. The intermediate transfer belt 62 is stretched by a plurality of tension rollers, and is rotated (rotated) in the direction of an arrow in the drawing by being driven by a drive roller among the plurality of tension rollers. The secondary transfer outer roller 64 is arranged at a position facing the secondary transfer inner roller 63 and the intermediate transfer belt 62 of the plurality of tension rollers with the intermediate transfer belt 62 interposed therebetween, and the toner image on the intermediate transfer belt 62 is used as a recording material. It constitutes a secondary transfer unit T2 to be transferred. A fixing device 7 is arranged downstream of the secondary transfer unit T2 in the recording material transport direction.

Image formation in the image forming apparatus 100 configured in this way is performed as follows. First, the surface of the photosensitive drum 1A is uniformly charged by the charging roller 2A. By exposing the charged surface with the laser scanner 3A, an electrostatic latent image is formed on the photosensitive drum 1A. By adhering toner from the developing device 4A to the electrostatic latent image thus obtained, the electrostatic latent image is developed as a toner image. This toner image is transferred onto the intermediate transfer belt 62 by the primary transfer roller 61A. Such operations are also sequentially performed in the image forming units M, C, and K, and the toner images of four colors are superimposed on the intermediate transfer belt 62.

Then, after the four-color toner images are superimposed and transferred on the intermediate transfer belt 62, the four-color toner images are transferred to the recording material conveyed from the feed cassette (not shown) to the secondary transfer unit T2. This recording material is heated and pressurized by the fixing device 7 to be fixed, and then discharged to the outside of the image forming device 100. The residual toner remaining on the photosensitive drum 1A after the transfer is removed by the cleaning device 8A.

[Developer]
Next, the developing apparatus 4A of the present embodiment will be described with reference to FIGS. 2 and 3. Since the other developing devices 4B, 4C, and 4D have the same configuration as the developing device 4A, description and illustration thereof will be omitted.

The developing apparatus 4A includes a developing container 41, a cylindrical developing sleeve 44a (developing rotating body) as a developing agent carrier, and a regulating member 42. The developing container 41 can contain a developing agent containing a non-magnetic toner and a magnetic carrier. The developing container 41 has an opening at a portion facing the photosensitive drum 1A (FIG. 1), and the developing sleeve 44a is rotatably arranged so as to partially expose the opening.

The developing sleeve 44a is arranged so as to face the photosensitive drum 1A, and by rotating, the developing agent in the developing container is supported and conveyed to the region facing the photosensitive drum 1A (development region), and is carried on the photosensitive drum 1A (image). Develop an electrostatic latent image (on the carrier). The developing sleeve 44a is arranged so that the direction of the rotation axis is substantially parallel to the direction of the rotation axis of the photosensitive drum 1A.

On one end side of the developing device 4A in the longitudinal direction (direction of the rotation axis of the developing sleeve 44a), a driving force transmitting member 221 such as a gear or a coupling for transmitting the driving force for rotationally driving the developing sleeve 44a to the developing sleeve 44a. , And a driving device 220 such as a motor that applies a driving force to the driving force transmitting member 221 is provided. The driving force transmission member 221 and the driving device 220 are arranged side by side along the longitudinal direction of the developing device 4A (the direction of the rotation axis of the developing sleeve 44a).

By inputting the driving force of the motor (driving device 220) to the coupling (driving force transmitting member 221) shown in FIG. 8 provided at the end of the developing sleeve 44a in the direction of the rotation axis, the developing sleeve 44a Is rotationally driven in the direction of the arrow α in FIG. The rotation direction of the developing sleeve 44a is the same direction (forward direction) as the rotation direction of the photosensitive drum 1A (arrow β direction in FIG. 3) at a position facing the photosensitive drum 1A.

The developing sleeve 44a is provided with a magnet roll 44b as a magnetic field generating means in a non-rotating manner. The magnet roll 44b has a plurality of magnetic poles along the rotation direction of the developing sleeve 44a, and magnetically attracts the developer to the surface of the non-magnetic developing sleeve 44a. The regulating member 42 is arranged through a predetermined gap of the developing sleeve 44a, and regulates the height of the magnetic spikes of the developing agent (layer thickness of the developing agent) formed on the developing sleeve 44a. The magnetic spikes are supported on the developing sleeve 44a in a state in which carriers to which toner is attached are connected like spikes.

Further, the developing container 41 is divided into a first developer transport path (first chamber) 45a and a second developer transport path (second chamber) 45b by a partition wall 43 extending in the horizontal direction. .. The first developer transport path 45a has a first screw 46a as a first transport member, and the second developer transport path 45b has a second screw 46b as a second transport member. Each is arranged.

The first screw (second transport screw) 46a agitates and transports the toner replenished to the developing container 41 from the toner replenishing device (not shown) and the developer in the first developer transport path 45a. Make the toner concentration uniform. The second screw (first transport screw) 46b agitates and transports the developer in the second developer transport path 45b. At both ends of the partition wall 43 in the width direction (direction of the rotation axis of the developing sleeve 44a), communication ports (first communication portions) for communicating the first developer transport path 45a and the second developer transport path 45b, respectively. , The second communication part) is formed. The first communication section connects the first developer transfer path 45a and the second developer transfer path 45b so that the developer moves from the first developer transfer path 45a to the second developer transfer path 45b. Communicate. The second communication unit communicates the first developer transfer path 45a and the second developer transfer path 45b so that the developer moves from the second developer transfer path 45b to the first developer transfer path 45a. do. Further, the second screw 46b conveys the developer in the first direction from the first communication section to the second communication section. The first screw 46a conveys the developer in the second direction from the second communication section to the first communication section. As a result, the first developer transport path 45a and the second developer transport path 45b form a circulation path in which the developer circulates.

In the present embodiment, the developer housed in the developing container 41 is a two-component developing agent in which a negatively charged non-magnetic toner and a magnetic carrier are mixed. The non-magnetic toner is a resin such as polyester or styrene containing a colorant, a wax component, or the like and pulverized or polymerized to form a powder. In this embodiment, one having an average particle size of 5 μm was used. The magnetic carrier is obtained by applying a resin coating to the surface layer of a core made of resin particles obtained by kneading ferrite particles or magnetic powder.

The process of developing the toner on the photosensitive drum 1A in the developing region will be described. As shown in FIG. 1, the photosensitive drum 1A is uniformly charged to the charging potential Vd [V] by the charging roller 2A, and then the image portion on which the image on the photosensitive drum 1A is formed is formed by the laser scanner 3A. It is exposed and has an exposure potential of Vl [V]. A DC voltage or a voltage obtained by superimposing an AC voltage on the DC voltage is applied to the developing sleeve 44a. When the voltage of the DC component of the developing sleeve 44a is Vdc, the absolute value | Vdc-Vl | of the difference from the exposure potential is called Vcont, which creates an electric field that carries the toner to the image unit.

Further, the absolute value | Vdc-Vd | of the difference between the DC voltage Vdc and the charging potential Vd is called Vback, and creates an electric field for the toner to be pulled back from the photosensitive drum 1A in the direction of the developing sleeve 44a. This is provided to suppress the so-called fog phenomenon in which the toner adheres to the non-image portion.

The developing sleeve 44a rotates in the direction of the arrow α in FIG. 3, attracts the developing agent by the magnetic field of the magnet roll 44b inside, and conveys the developing agent in the direction of the regulating member 42. The layer thickness of the spiked developer is regulated by the regulating member 42, and when it passes through the gap between the developing sleeve 44a and the regulating member 42, a developer layer having a predetermined layer thickness is formed on the developing sleeve 44a. The developer layer is then supported and transported to the developing region facing the photosensitive drum 1A as the developing sleeve 44a rotates, and develops an electrostatic latent image formed on the surface of the photosensitive drum 1A with magnetic spikes formed. do. During development, the developer comes into contact with the photosensitive drum 1A and develops a latent image at that contact. Therefore, the space between the photosensitive drum 1A and the developing sleeve 44a is filled with the developing agent. The developer after being subjected to development is peeled from the developing sleeve 44a at the peeling region as the developing sleeve 44a rotates, and returns to the inside of the developing container 41.

In such a developing apparatus 4A of the present embodiment, the developing agent is supplied from the second developer transport path (supply chamber) 45b to the developing sleeve 44a and developed in the first developer transport path (collection chamber) 45a. This is a so-called function-separated developing device that recovers the developing agent from the sleeve 44a. Further, the developing device 4A is a so-called vertical stirring type developing device in which the second developer transport path 45b is arranged above the first developer transport path 45a, and the developing sleeve 44a is the photosensitive drum 1A. At the position facing the above, it rotates so as to go downward in the direction of gravity.

In the function-separated developing apparatus, the developing agent is conveyed from the upstream side to the downstream side in the developing agent conveying direction in the first developing agent conveying path 45a, and the developing agent is recovered from the developing sleeve 44a. The amount of the developer in the developer transport path 45a of No. 1 tends to be larger on the downstream side in the developer transport direction than on the upstream side. Further, in the functional separation type developing apparatus, the developing agent is conveyed from the upstream side to the downstream side in the developing agent conveying direction in the second developing agent conveying path 45b, and the developing agent is supplied to the developing sleeve 44a. The amount of the developer in the second developer transport path 45b tends to be smaller on the downstream side in the developer transport direction than on the upstream side.

Therefore, in the function-separated developing apparatus, the height of the developer surface on the downstream side of the second developer transport path 45b in the developer transport direction is the height of the developer surface in the second developer transport path 45b. It is lower than the height of the developer surface on the upstream side of. The second screw 46b has a lower height of the developer surface in the second developer transfer path 45b than a higher height of the developer surface in the second developer transfer path 45b. There is a tendency for the density of the amount to be applied in the air to increase due to the increase in the amount of flipping up.

Further, as the developing sleeve 44a is driven to rotate, airflow is taken in from the gap between the developing sleeve 44a and the developing container 41. On the upstream side of the second developer transport path 45b in the developer transport direction, the height of the developer surface is high and the developer is filled with the developer, so that the air flow is small and flows into the developing container 41. The flow rate of airflow tends to be small. On the other hand, on the downstream side of the second developer transport path 45b in the developer transport direction, the height of the developer surface is low and the amount of the developer is small, so that the flow path of the air flow is large and the inside of the developing container 41. The flow rate of the airflow that flows into the image tends to increase.

Since the internal pressure in the developing container 41 rises due to the air flow taken into the developing container 41 by driving the developing sleeve 44a, toner tends to scatter from the gap between the developing sleeve 44a and the developing container 41 in order to maintain the internal pressure. Therefore, in the second developer transport path 45b where the height of the developer surface is lower than that on the upstream side in the developer transport direction in the second developer transport path 45b where the height of the developer surface is higher. The amount of airflow in and out of the developing container 41 increases on the downstream side in the developing agent transport direction.

For this reason, in the function-separated type developing apparatus, the height of the developer surface is lowered in the air on the downstream side in the developer transporting direction in the second developer transport path 45b by flipping up the second screw 46b. The amount of toner scattered tends to increase because the density of the agent is increased and the flow rate of the airflow driven by the developing sleeve 44a is also large.

[Shape of developing container]
Next, the shape of the developing container 41 will be further described with reference to FIGS. 2 and 3. The developing container 41 has a protruding portion (toner receiving portion) 48 formed so as to project from the lower end portion toward the photosensitive drum 1A. Further, the developing container 41 has end ribs 49a and 49b formed so as to project toward the photosensitive drum 1A at both ends in the longitudinal direction intersecting the rotation direction (arrow α direction) of the developing sleeve 44a, respectively.

The protruding portion 48 is arranged downstream of the closest position (development position) P between the developing sleeve 44a and the photosensitive drum 1A in the rotational direction of the developing sleeve 44a. In the present embodiment, it is provided below the closest position P in the direction of gravity, and in the illustrated example, it is provided at the lower end of the developing container 41. The developing container 41 has a wall portion 41b that forms a first developer transport path 45a. The wall portion 41b is provided on the photosensitive drum 1A side of the first developer transport path 45a, and the upper end portion faces the developing sleeve 44a. The projecting portion 48 is formed so as to project from the lower end portion of the wall portion 41b toward the photosensitive drum 1A.

Such a protrusion 48 is arranged along the longitudinal direction of the developing container 41 (the direction of the rotation axis of the developing sleeve 44a) that intersects the rotating direction of the developing sleeve 44a, and has a gap between the protruding portion 48 and the photosensitive drum 1A. It is formed to have. In the present embodiment, the protruding portion 48 is provided over the entire area between the end ribs 49a and 49b. The gap between the protruding portion 48 and the photosensitive drum 1A is, for example, 2 mm.

Further, at the tip of the protruding portion 48, a bent portion 48a that is bent upward is formed so that the toner that has fallen from the developing sleeve 44a can be held. The bent portion 48a is curved or inclined along the curvature of the surface of the photosensitive drum 1A. The gap between the tip of the protruding portion 48 including the bent portion 48a and the photosensitive drum 1A is set to, for example, 2 mm. The bent portion 48a may be omitted.

The end rib 49a as the first end protrusion is provided at one end of the developing container 41 in the longitudinal direction. In the present embodiment, the front side of the image forming apparatus, that is, the one-sided end portion on which the apparatus is operated is referred to as the other end portion in the longitudinal direction. On the other hand, the end rib 49b as the second end protrusion is provided at the end of the developing container 41 on the opposite side in the longitudinal direction. The end on the opposite side in the longitudinal direction is the end on the rear side (back side) of the image forming apparatus, and is called one end in the longitudinal direction.

Such end ribs 49a and 49b are arranged so as to extend from at least the closest position P to the protruding portion 48 and to have a gap between the end ribs 49a and 49b and the photosensitive drum 1A. In the present embodiment, the end ribs 49a and 49b are provided in a range from a position above the closest position in the direction of gravity to the lower end of the developing container 41, and face each other with the photosensitive drum 1A via a gap. ing. The end ribs 49a and 49b are the range in which the developer supported on the developing sleeve 44a comes into contact with the photosensitive drum 1A and this range when viewed from the longitudinal direction of the developing container 41 intersecting the rotation direction of the developing sleeve 44a. It is preferable that the film is arranged so as to overlap the range below the direction of gravity. The gap between the end ribs 49a and 49b and the photosensitive drum 1A is, for example, 2 mm.

[Airflow space]
In the present embodiment, as described above, the airflow space portion 52 as the first airflow space portion is formed by forming the projecting portions 48 and the end ribs 49a and 49b in the developing container 41. That is, the airflow space portion 52 has a space surrounded by a photosensitive drum 1A, a developing sleeve 44a, a protruding portion 48, and end ribs 49a and 49b, and is a portion where airflow can flow through this space. be. The airflow space 52 is arranged on the side of the developing container 41 facing the photosensitive drum 1A, and the toner scattered from the developing sleeve 44a formed from one end side to the other end side in the rotation axis direction of the developing sleeve 44a is transferred. It is a flow path of air for recovery. In FIG. 3, it is a satin-finished portion excluding the portion showing the developer t.

Here, FIG. 3 is a cross-sectional shape at the position of the broken line A portion of FIG. 2, which is the central portion of the developing apparatus 4A in the longitudinal direction. The developing agent t is supported on the developing sleeve 44a as shown by the satin finish, and the gap between the developing sleeve 44a and the photosensitive drum 1A is closed by the developing agent t.

Here, as the speed of the apparatus increases, the developer tends to scatter from the developing sleeve 44a. In the present embodiment, the developer scattered from the developing sleeve 44a is sucked through the airflow space 52 to prevent the developing agent from scattering to the outside of the developing apparatus 4A. Therefore, as shown in FIG. 2, of the end ribs 49a and 49b, the front end rib 49a has an inflow opening 50 as an airflow inflow portion, and the rear end rib 49b has an airflow suction. The suction opening 51 as a portion is opened. Then, the airflow is circulated in the airflow space 52 by using the entrances and exits of these two airflows.

This will be described more specifically. The inflow opening 50 as the first opening is formed in the end rib 49a so as to penetrate the end rib 49a in the longitudinal direction, and an opening through which airflow can flow into the airflow space 52 from the outside of the developing container 41. It is a department. The suction opening 51 as the second opening is formed in the end rib 49b so as to penetrate the end rib 49b in the longitudinal direction, and is an opening capable of sucking airflow from the airflow space 52.

The inflow opening 50 is formed in the rotational direction of the developing sleeve 44a, downstream of the closest position P of the developing container 41 and further upstream of the upstream end 41a (FIG. 3) of the portion facing the developing sleeve 44a. ing. Further, the inflow opening 50 is formed so as to open to the upstream side of the portion (development nip portion) where the developer supported on the developing sleeve 44a comes into contact with the photosensitive drum 1A in the rotation direction of the developing sleeve 44a. ..

In the present embodiment, the inflow opening 50 is formed in a range including the closest position P with respect to the rotation direction of the developing sleeve 44a. In other words, the inflow opening 50 is formed upstream of the upstream end 41a so as to include the upstream of the developing nip portion, which is a portion where the developer supported on the developing sleeve 44a comes into contact with the photosensitive drum 1A.

Specifically, in the wall portion 41b of the developing container 41, the upper end in the gravity direction is the above-mentioned upstream end 41a at the portion facing the developing sleeve 44a. An inflow opening 50 is formed above the horizontal line L (see FIG. 5) passing through the upstream end 41a. That is, the lower end of the inflow opening 50 in the gravity direction is above the horizontal line L passing through the upstream end 41a. On the other hand, the upper end of the inflow opening 50 in the gravity direction is preferably located below the upper end of the developing sleeve 44a in the gravity direction.

Further, the inflow opening 50 is formed so as to open on the photosensitive drum 1A side (image carrier side). As a result, when the developing sleeve 44a is assembled to the developing container 41, the rotating shaft 44c of the developing sleeve 44a can pass through the inflow opening 50. The rotary shaft 44c that has passed through the inflow opening 50 is rotatably supported by a rotary support portion (not shown).

It is preferable that the end portion of the inflow opening 50 opposite to the photosensitive drum 1A does not enter the first developer transport path 45a and the second developer transport path 45b. In other words, the inflow opening 50 is preferably formed within a range that overlaps with the developing sleeve 44a when viewed from the longitudinal direction. This is because if the inflow opening 50 is also open in the first developer transport path 45a or the second developer transport path 45b, the developer is likely to leak to the outside from the developer transport path through the opening. This is to become.

The suction opening 51 is formed downstream of the developing nip in the rotational direction of the developing sleeve 44a. In the present embodiment, the suction opening 51 is formed so as to open within the range of the airflow space 52 when viewed from the longitudinal direction. The opening shape of the suction opening 51 is substantially similar to the cross-sectional shape orthogonal to the longitudinal direction of the airflow space 52, and is substantially triangular in the present embodiment.

Further, the suction opening 51 is connected to the suction fan 70 via a duct 53 or the like, as shown in FIG. 7, which will be described later. The suction fan 70 as an airflow generating means for generating an airflow is installed on the apparatus main body side of the image forming apparatus, and is connected to the duct 53 when the developing apparatus 4A is attached to the apparatus main body. The detailed configuration of this point will be described later. The suction opening 51 is an opening capable of sucking airflow from the airflow space 52 by the airflow generated by the suction fan 70.

Here, as shown in FIG. 2, the developing sleeve 44a has a first region (image forming region) M formed so that the surface supports the developing agent in the longitudinal direction (rotational axis direction), and the developing agent. It has a second region N formed so as not to support it. The first region M is a region formed in the intermediate portion in the longitudinal direction of the developing sleeve 44a and corresponding to the maximum image region on which an image can be formed on the photosensitive drum 1A (on the image carrier). That is, with respect to the longitudinal direction (rotational axis direction) of the photosensitive drum 1A, the maximum region in which an electrostatic latent image can be formed is the maximum image region, and the developing sleeve 44a carries a developer so that the electrostatic latent image can be developed. The area is the first area.

In the first region of the developing sleeve 44a, for example, irregularities and grooves are formed on the surface of the developing sleeve 44a to facilitate carrying the developing agent. Specifically, the first region is a region where the surface is blasted, a plurality of grooves along the longitudinal direction are formed in the circumferential direction, and recesses called digging are formed at a plurality of locations on the surface. The area.

On the other hand, the second region is a region existing at both ends of the first region with respect to the longitudinal direction of the developing sleeve 44a, and is a region corresponding to a region deviating from the maximum image region. In the second region of the developing sleeve 44a, irregularities and the like are not formed as in the first region, and the surface is a smooth cylindrical surface. The magnet roll 44b arranged in the developing sleeve 44a exists at least in the entire longitudinal direction of the first region, and can support the developer in the first region. Normally, the end portion of the magnet roll 44b is arranged so as to enter a part of the second region, but the end portion of the magnet roll 44b has a ripple in the magnetic flux density, and the developer is placed on the developing sleeve 44a. It is difficult to form a magnetic field that supports the magnet.

As described above, since it is difficult for the developer to be supported in the second regions at both ends of the developing sleeve 44a, the airflow easily passes around the developing sleeve 44a. In the second region of the developing sleeve 44a, the developing agent in the developing container is not supplied, and the developing agent is almost absent on the surface. Therefore, in the second region, there is no developer in the gap between the developing sleeve 44a and the photosensitive drum 1A. Therefore, in the second region, airflow can flow upstream and downstream of the closest position P with respect to the rotation direction of the developing sleeve 44a.

On the other hand, in the first region of the developing sleeve 44a, as shown in FIG. 3, the developing agent is supported on the surface, and the gap between the developing sleeve 44a and the photosensitive drum 1A is closed by the developing agent. Therefore, in the first region, it is difficult for airflow to flow upstream and downstream of the closest position P with respect to the rotation direction of the developing sleeve 44a.

From the above, the airflow flowing in from the inflow opening 50 opened so as to face the other end in the longitudinal direction of the developing sleeve 44a flows around the second region and into the airflow space 52. At this time, due to the rotation of the developing sleeve 44a, the airflow flowing in from the inflow opening 50 is easily carried to the airflow space 52 located downstream of the inflow opening 50 in the rotation direction of the developing sleeve 44a.

[Toner scattering]
Next, the state of air flow and toner scattering between the developing device 4A and the photosensitive drum 1A when the developing device 4A and the photosensitive drum 1A are driven will be described with reference to FIGS. 4 and 5. FIG. 4 shows the air flow and the toner flow in the cross section of the central portion in the longitudinal direction (the portion A of the broken line in FIG. 2) between the developing device 4A and the photosensitive drum 1A. The solid arrow indicates the direction of toner scattering.

The developing sleeve 44a and the photosensitive drum 1A are driven to generate an air flow on the surface. At this time, the airflow on the surface of the developing sleeve 44a is defined as the sleeve flow 410 and 420, and the airflow on the surface of the photosensitive drum 1A is defined as the drum flow 110 and 120. Since the sleeve flow 420 flows into the developing container 41, the pressure rises, an air flow 430 from the inside of the developing container 41 to the outside is generated, and the developer (here, toner) in the developing container 41 rides on the air flow 430. It flows out of the developing container 41. Then, the outflowing toner scatters along the drum flow 120 through the air flow 440 and becomes scattered toner.

Further, as described above, an airflow space portion 52 closed by a developing container 41, a developing sleeve 44a, a photosensitive drum 1A, a protruding portion 48, and end ribs 49a and 49b is formed on the downstream side of the developing nip portion. There is. Therefore, the return flow 130 of the drum flow is generated, and a part of the scattered toner is collected by the return flow 130 to the developing sleeve 44a.

Most of the scattered toner is received by the protrusion 48 and stays there. However, if the amount of this scattered toner is large, it accumulates on the protruding portion 48 while the image formation is continued, and if the capacity of the protruding portion 48 is exceeded, it spreads to the outside, causing stains in the apparatus and stains on the roller that conveys the recording material. It becomes. When toner adheres to the rollers, the toner also adheres to the recording material conveyed to the rollers, leading to image defects.

The sleeve flow 450 and the drum flow 150 are also generated on the upstream side of the developing nip portion, but since the developer is present in the developing nip portion in the first region, the sleeve flow 450 and the drum flow 150 are the developing nip portions. It does not enter the downstream side of the, and becomes a return flow as shown by the arrow.

Next, FIG. 5 shows the air flow and the toner flow in the cross section of the second region (broken line B portion in FIG. 2) at the end in the longitudinal direction between the developing device 4A and the photosensitive drum 1A. The solid arrow indicates the direction of toner scattering, and the dotted arrow indicates the combined airflow of each airflow. In FIG. 5, unlike FIG. 4 described above, the amount of toner contained in the airflow is very small because there is no developer on the developing sleeve 44a. On the other hand, since there is no developer in the developing nip, the airflow passes through and the airflow from the upstream of the developing nip flows downstream as it is. Therefore, the synthetic airflow 500 as shown by the dotted line is generated, the air pressure is low on the upstream side of the developing nip portion, and the air pressure is high on the downstream side.

From the above, by providing the inflow opening 50 at the end upstream of the developing sleeve 44a in the rotational direction with respect to the developing nip as in the front end of the developing container 41, a negative pressure is obtained from the inflow opening 50. Air easily flows into the area on the upstream side of the developing nip. Then, the air that has flowed in is sent into the airflow space 52 along the combined airflow 500.

As described above, at the front end of the developing device 4A in the longitudinal direction, the airflow flows in from the inflow opening 50 by the sleeve flow and the drum flow described above, and the airflow is pushed into the airflow space 52. The pushed airflow moves in the airflow space 52 from the front side to the back side. At this time, the above-mentioned scattered toner is involved and collected. Then, the airflow containing the scattered toner on the back side is sucked into the suction opening 51. The sucked airflow is sucked into the duct 53 connected to the suction fan 70 (FIG. 7) and discharged to the outside of the image forming apparatus 100 as described later.

As described above, the developing device 4A is a function-separated type developing device. In the function-separated developing apparatus, the amount density in the air due to the flip-up of the second screw 46b on the downstream side in the developer transporting direction in the second developer transport path 45b where the height of the developer surface is lowered. In addition, the flow rate of the airflow driven by the developing sleeve 44a is also large, so that the amount of toner scattered tends to increase.

Therefore, in the first embodiment, the developer in the second developer transport path 45b tends to increase the amount of toner scattered in the suction opening 51 due to the low height of the developer surface. It is provided on the downstream side in the transport direction (the end on the back side in the longitudinal direction of the developing device 4A). As a result, at the end portion on the back side in the longitudinal direction of the developing apparatus 4A, the toner scattered from the gap between the developing container 41 and the developing sleeve 44a is sucked into the suction opening 51, and the effect of collecting the scattered toner can be further enhanced. can.

[Cooling configuration of developing device]
Next, the cooling configuration of the developing apparatus 4A of the present embodiment will be described. Here, as the speed of the image forming apparatus has increased in recent years, the stirring speed of the developer in the developing apparatus has also increased, and the deterioration of the chargeability of the toner and the image defect due to the temperature rise of the toner due to this have become problems. ing. Therefore, in the present embodiment, a cooling duct 55 is provided as a second airflow space for flowing an airflow for cooling the developing apparatus 4A.

As shown in FIGS. 2, 3, 6 and 7, the cooling duct 55 is provided on the outside of the developing container 41 on the opposite side (back side) of the developing sleeve 44a along the longitudinal direction, and the air flow flows inside. It is possible. That is, the cooling duct 55 is arranged on the side of the developing container 41 opposite to the side facing the photosensitive drum 1A, and is formed from one end side to the other end side of the developing sleeve 44a in the rotation axis direction. It is a duct for forming an air flow path for cooling. As shown in FIG. 2, at the other end (front end) of the cooling duct 55 in the longitudinal direction, an inflow opening 54 for sending airflow to the cooling duct 55 is provided at one end (rear end) in the longitudinal direction. Is formed with discharge openings 56 for discharging the airflow flowing through the cooling duct 55.

Further, as shown in FIG. 3, a plurality of heat radiating plates 111 are provided in the cooling duct 55 substantially parallel to each other along the longitudinal direction. Specifically, the plurality of heat radiating plates 111 are provided on a part of the back surface side of the developing container 41 and have a rib shape protruding in the cooling duct 55 in parallel with the blowing direction of the cooling air. As the heat radiating plate 111, a material having high thermal conductivity, for example, an aluminum alloy (A6063) is used. In this way, the cooling efficiency can be improved by increasing the surface area of the heat radiating plate 111 that comes into contact with the cooling air.

As shown in FIG. 2, an airflow discharge portion 57 as a discharge portion for discharging the airflow is connected to one end in the longitudinal direction of the cooling duct 55. That is, the discharge opening 56 of the cooling duct 55 is open to the airflow discharge part 57, and the airflow flowing through the cooling duct 55 flows to the airflow discharge part 57. On the other hand, as shown in FIG. 7, a cooling fan 67 for sending airflow to the cooling duct 55 is provided on the upstream side of the other end of the cooling duct 55 in the longitudinal direction in the flow direction of the airflow. That is, the cooling fan 67 is connected to the inflow opening 54 of the cooling duct 55, and the airflow is sent into the cooling duct 55 through the inflow opening 54.

[Suction of scattered toner and cooling of developing device]
In the present embodiment, as described above, the airflow space portion 52 in which the airflow for collecting the scattered toner flows and the cooling duct 55 in which the airflow for cooling the developing device 4A flows merge at the airflow discharge portion 57. do. Then, as shown in FIG. 11, which will be described later, the airflow discharge portion 57 is connected to the exhaust duct 71, which is a duct provided on the main body side of the image forming apparatus 100, and the airflow and the cooling duct 55 flowing through the airflow space portion 52 are connected. The airflow that has flowed flows through the exhaust duct 71. A suction fan 70 (FIG. 7) is provided in the exhaust duct 71, and the air flow in the exhaust duct 71 is sucked by the suction fan 70 and discharged to the outside of the machine through a filter (not shown).

This will be described in detail. As shown in FIG. 6, the inflow opening 54 opens upward in the vertical direction of the cooling duct 55, while the discharge opening 56 opens downward in the vertical direction of the cooling duct 55. In the present embodiment, the airflow discharge portion 57 through which the discharge opening 56 opens is also arranged near the lower end of the developing container 41. A duct 53 as a communication duct is connected to the airflow discharge portion 57 through which the suction opening 51 of the airflow space portion 52 opens. That is, as shown in FIGS. 6 and 8, the duct 53 is arranged so as to wrap around the lower side of the developing container 41 from the developing sleeve 44a side to the back side, and the airflow discharge arranged on the back side of the developing container 41. It is an airflow connecting portion connected to the portion 57. In other words, the duct 53 is connected to the airflow space 52 so that the airflow can flow between the airflow space 52 and is sucked so that the airflow flows between the suction opening 51 and the airflow discharge 57. The opening 51 and the airflow discharge portion 57 are connected. In the first embodiment, the duct 53 communicates with the airflow discharge portion 57, the suction opening 51, and the cooling duct 55. Although the first embodiment shows an example in which the developing container 41 and the duct 53 are integrally molded, it may be a modified example in which the developing container 41 and the duct 53 are separate members. Further, the duct 53 is not limited to a completely closed space, and may be a substantially closed space to the extent that airflow can flow between the suction opening 51 and the airflow discharge portion 57. ..

Here, the positional relationship between the airflow space portion 52, the inflow opening 50, the suction opening 51, the airflow discharge portion 57, the suction fan 70, the driving force transmission member 211, and the driving device 210 will be described with reference to FIG. .. As shown in FIG. 9, the side of the developing container 41 facing the photosensitive drum 1A is the front side of the developing container 41, and the side of the developing container 41 opposite to the side facing the photosensitive drum 1A is the developing container 41. The back side of. Further, as shown in FIG. 9, the other end side of the developing sleeve 44a in the longitudinal direction is the front side of the developing container 41, and the one end side of the developing sleeve 44a in the longitudinal direction is the back side of the developing container 41. .. Therefore, the other end side of the developing sleeve 44a in the rotation axis direction is on the upstream side in the first direction from the first region M, and one end side of the developing sleeve 44a in the rotation axis direction is in the first direction from the first region M. It is on the downstream side. As described above, the first direction is the developer transport direction of the second screw 46b.

The airflow space 52 is formed on the front side of the developing container 41 along the longitudinal direction of the developing device 4A (the direction of the rotation axis of the developing sleeve 44a). The inflow opening 50 is arranged on the front side of the developing container 41 and on the front side of the developing container 41. Further, the suction opening 51 is arranged on the front side of the developing container 41 and on the back side of the developing container 41. Further, the airflow discharge portion 57 is arranged on the back side of the developing container 41 and on the back side of the developing container 41.

The suction fan 70 is arranged on the back side of the developing container 41 and on the back side of the developing container 41. Further, the driving force transmission member 211 is arranged on the front side of the developing container 41 and on the back side of the developing container 41. Further, the drive device 210 is arranged on the front side of the developing container 41 and on the back side of the developing container 41.

As described above, the first embodiment has a configuration in which the scattered toner is conveyed by the air flow in the air flow space 52 and collected from the air flow discharge unit 57. In the first embodiment, in this configuration, the airflow space portion 52, the driving force transmission member 221 and the driving device 220 are arranged on the front side of the developing container 41. In such a configuration, when the airflow discharge portion 57 is arranged on the front side and the back side of the developing container 41, it is driven by the driving force transmitting member 211 arranged on the front side and the back side of the developing container 41. A space for arranging the suction fan 70 on the front side of the developing container 41 must be secured inside the apparatus so as not to interfere with the apparatus 210.

On the other hand, in the first embodiment, the duct 53 (airflow connecting portion) connecting the suction opening 51 and the airflow discharging portion 57 so that the airflow flows between the suction opening 51 and the airflow discharging portion 57. ) Is arranged so as to wrap around the lower side of the developing container 41 from the developing sleeve 44a side to the back side. As a result, the airflow discharge portion 57 can be arranged on the back side of the developing container 41, so that the suction fan 70 may also be arranged on the back side of the developing container 41.

That is, in the first embodiment, on the side opposite to the side (front side of the developing container 41) where the airflow space portion 52, the driving force transmission member 221 and the driving device 220 are arranged (the back side of the developing container 41). Since the suction fan 70 can be arranged, it is possible to prevent the apparatus from becoming large in size in order to secure a space for arranging the suction fan 70 on the front surface side of the developing container 41.

In addition, in FIG. 2 described above and FIG. 9 described later, the duct 53 is described so as to extend in the longitudinal direction from the suction opening 51 for the sake of simplicity, but in the present embodiment, FIGS. 8 and 10 As shown in the above, the duct 53 passes under the developing container 41. By arranging the duct 53 in this way, the developing apparatus can be made compact in the longitudinal direction. However, the arrangement of the duct 53 is not limited to this, and as shown in FIGS. 2 and 9, the duct 53 may be extended in the longitudinal direction and then connected to the airflow discharge portion 57 on the back surface side. Further, the position of the airflow discharge portion 57 is also different between FIGS. 2 and 9 and FIGS. 7 and 10, but in the present embodiment, the configuration is as shown in FIGS. 7 and 10. However, the position of the airflow discharge portion 57 is not limited to this, and may be the position shown in FIGS. 2 and 9.

FIG. 8 is a perspective view of the developing container 41 on the front side of the developing sleeve 44a, and the broken line arrow represents the flow of the air flow sucked from the suction opening 51. As shown by the broken line arrow in FIG. 8, the airflow sucked from the suction opening 51 moves to the downstream side in the longitudinal direction as it is, and then is first moved from the front side of the developing container 41 to the back side of the developing container 41 by the duct 53. Moves on the lower side of the developer transport path 45a (see FIG. 6). Then, as shown by the broken line in FIG. 9, it moves to the airflow discharge portion 57 installed on the back side of the developing container 41.

On the other hand, as shown in FIG. 7, the airflow sent from the cooling fan 67 and sucked from the inflow opening 54 passes through the cooling duct 55 provided on the back side of the developing container 41 as shown by the chain line in FIG. As per, the developing device 4A is cooled. Then, it moves from the discharge opening 56 to the airflow discharge part 57. In this way, in the airflow discharge section 57, the airflow containing the scattered toner that flows through the airflow space section 52 and is sucked from the suction opening 51 and the cooling of the developing device 4A that flows through the cooling duct 55 and is sucked from the discharge opening 56. The airflow for is merged.

[Connection between the airflow discharge part and the duct on the main body side]
The airflow merged at the airflow discharge unit 57 as described above is sent to the exhaust duct 71 on the main body side. In the present embodiment, as shown in FIG. 10, the airflow discharge portion 57 has one discharge port (opening of the duct) 65 for discharging the merged airflow. The one discharge port 65 may be an opening for discharging the airflow merged by the airflow discharge portion 57, and for example, the opening may have a partition plate or a louver. The exhaust duct 71 on the main body side shown in FIG. 11 is connected to the airflow discharge unit 57, and allows the airflow sucked from the discharge port 65 by the suction fan 70 to flow. Hereinafter, the configuration of the connection portion between the airflow discharge portion 57 and the exhaust duct 71 on the main body side will be described with reference to FIGS. 10 to 12.

FIG. 10 is a view of the developing container 41 as viewed from the back side. The broken line arrow indicates the flow of the airflow sent from the airflow space portion 52 to the airflow discharge portion 57 via the duct 53, and the alternate long and short dash line arrow indicates the cooling. The flow of the airflow sent from the duct 55 to the airflow discharge portion 57 is represented by each. The airflow discharge portion 57 is connected to the main body side connection portion 58 provided in the exhaust duct 71 on the main body side, and has a developing side connection portion 59 for passing the airflow. The developing side connecting portion 59 is an area for connecting to the main body side connecting portion 58, and more specifically, a region in contact with the main body side connecting portion 58. As described above, the airflow discharge portion 57 has a developing side connecting portion 59 connected to the exhaust duct 71 on the main body side, and one discharging port 65 is formed in the developing side connecting portion 59. The airflow for collecting the toner scattering and the airflow for cooling the developing device 4A merge at the airflow discharge unit 57 and are discharged from the discharge port 65.

FIG. 11 is a view of the main body side connection portion 58 of the exhaust duct 71 provided on the device main body side of the image forming apparatus as viewed from diagonally above the surface connecting the air flow discharge portion 57 to the development side connection portion 59. The main body side connection portion 58 is connected to the development side connection portion 59. The main body side connection portion 58 is formed with one suction port 60 for sucking the airflow exhausted from the discharge port 65 of the airflow discharge portion 57. The suction port 60 is formed at a position overlapping the discharge port 65 when the main body side connection portion 58 is connected to the development side connection portion 59, and sucks the air flow discharged from the discharge port 65. In this embodiment, a sealing material 66 such as urethane foam is arranged around the suction port 60 of the main body side connection portion 58. Then, the gap between the developing side connecting portion 59 and the main body side connecting portion 58 is sufficiently sealed by the sealing material 66.

There is no problem if the suction port 60 and the discharge port 65 overlap with each other if the suction port 60 covers about 80% or more of the area of the discharge port 65, but 90% or more, or the suction port 60 is the discharge port 65. It is more preferable to include the whole of. FIG. 12 is a schematic view showing the degree of overlap between the suction port 60 and the discharge port 65. As shown in FIG. 12, in the present embodiment, the suction port 60 has a larger opening area than the discharge port 65, and when the main body side connection portion 58 is joined to the development side connection portion 59, the suction port 60 is opened. It is designed to cover the entire outlet 65.

Specifically, the suction opening 51 is trapezoidal with a base of 9.2 [mm], an upper side of 5.2 [mm], and a height of 5.9 [mm], and the inflow opening 54 is 10.5 [. It is a rectangle of mm] × 20.1 [mm], and the discharge opening 56 is a rectangle of 10.5 [mm] × 15 [mm]. The discharge port 65 is a rectangle of 30 [mm] × 12.5 [mm], and the suction port 60 is a rectangle of 36 [mm] × 17 [mm].

As described above, the airflow containing the scattered toner delivered to the suction port 60 on the main body side and the airflow for cooling the developing device 4A sucked from the inflow opening 54 are the same suction fan 70 (FIG. 7). As a result, it passes through the exhaust duct 71 in the main body together. Then, the toner is discharged to the outside of the machine through the provided toner filter (not shown). The suction fan 70 is installed downstream of the toner filter. In the present embodiment, both the suction fan 70 and the cooling fan 67 (FIG. 7) for letting the air flow into the inflow opening 54 use a sirocco fan.

As described above, in the first embodiment, the side opposite to the side (front side of the developing container 41) where the airflow space portion 52, the driving force transmission member 221 and the driving device 220 are arranged (the back surface of the developing container 41). A suction fan 70 was placed on the side). As a result, it is possible to prevent the apparatus from becoming large in size in order to secure a space for arranging the suction fan 70 on the front surface side of the developing container 41.

Further, in the present embodiment, by adopting the above configuration, even in the developing apparatus provided with both the airflow space portion 52 for collecting the scattered toner and the cooling duct 55 for cooling the developing apparatus 4A, the apparatus is also an apparatus. It is possible to suppress the increase in size. That is, in the present embodiment, these airflows are merged with one discharge port 65 and exhausted together with the exhaust duct 71 to the outside of the machine. Therefore, it is not necessary to provide a plurality of connection portions on the main body side and a plurality of connection portions on the developing device side, and it is possible to take measures against toner scattering and toner deterioration without inviting an increase in size or cost of the main body.

In the above description, a gap is provided between the end ribs 49a and 49b and the photosensitive drum 1A. However, this gap may be eliminated. For example, an elastic member provided so as to elastically contact the photosensitive drum 1A at the end rib 49a as the first end protrusion and the end rib 49b as the second end protrusion. prepare. Examples of the elastic member include a porous body such as a sponge made of urethane or the like, a non-woven fabric, a sheet-like member, and the like. Examples of the sheet-shaped member include a PET (polyethylene terephthalate) sheet and a urethane sheet.

Further, in the above description, the inflow opening 50 is formed only on the end rib 49a side. However, the inflow opening 50 may also be formed at the end rib 49b. That is, the inflow opening 50 may be formed on both the end ribs 49a and 49b, respectively. The inflow opening 50 formed in the end rib 49b may have the same position and shape in the rotational direction as the inflow opening 50 formed in the end rib 49a.

The air for circulating the air flow in the air flow space 52 mainly flows in through the inflow opening 50, but in addition to this, also from the gap formed between the protrusion 48 and the photosensitive drum 1A. It may flow in. That is, the airflow space portion 52 is not limited to a completely closed space, but may be a substantially closed space capable of forming an airflow, and the protruding portion 48 and the photosensitive drum 1A may be formed. Air may flow in through the gaps formed between them.

<Second embodiment>
The second embodiment will be described with reference to FIGS. 13 to 15. In the first embodiment described above, the airflow containing the scattered toner and the airflow for cooling the developing device 4A merge at the airflow discharge unit 57 and are passed from one discharge port 65 to the exhaust duct 71 on the main body side. I did. On the other hand, in the present embodiment, the airflow discharge unit 57A is formed with two discharge ports 65a and 65b for discharging the two airflows, respectively. Since other configurations and operations are the same as those of the first embodiment described above, the same reference numerals are given to the same configurations, and the description and illustration are omitted or simplified. I will explain mainly.

When the cooling fan 67 (FIG. 7) for pushing the airflow is installed upstream of the inflow opening 54 as in the first embodiment described above, the following problems may occur. That is, the airflow containing the scattered toner that has passed through the airflow space 52 and the airflow that has been pushed into the inflow opening 54 by the cooling fan 67 and passed through the cooling duct 55 merge at the airflow discharge portion 57. At this time, as shown by the solid line in FIG. 13, the airflow pushed by the cooling fan 67 may flow back through the duct 53 toward the suction opening 51 (see FIG. 9 and the like) in the airflow discharge portion 57. .. When the airflow flows back through the duct 53, the airflow containing the scattered toner cannot be sufficiently sucked, and the scattering of the toner cannot be sufficiently suppressed.

Therefore, in the present embodiment, such an adverse effect is suppressed by separately exhausting the airflow containing the scattered toner sucked from the suction opening 51 and the airflow passing through the cooling duct 55. That is, also in the case of the present embodiment, there is an airflow discharge unit 57A to which these two airflows are sent. The airflow discharge portion 57A discharges the airflow flowing through the discharge port 65a as the first discharge port for discharging the airflow flowing through the airflow space portion 52 as the first airflow space portion and the cooling duct 55 as the second airflow space portion. A discharge port 65b as a second discharge port is formed. Hereinafter, a specific description will be given.

FIG. 14 is a view of the developing container 41 of the present embodiment as viewed from the back side. The dashed arrow represents the flow of airflow sent from the airflow space 52 to the airflow discharge section 57A via the duct 53, and the alternate long and short dash arrow represents the flow of airflow sent from the cooling duct 55 to the airflow discharge section 57A. ing. The airflow discharge portion 57A is connected to the main body side connection portion 58 provided in the exhaust duct 71 on the main body side, and has a developing side connection portion 59A for passing the airflow.

The airflow discharge portion 57A of the present embodiment has a development side connection portion 59A connected to an exhaust duct 71 (FIG. 11) on the main body side, and two discharge ports 65a and 65b are formed in the development side connection portion 59A. There is. The airflow for collecting the toner scattering is discharged from the discharge port 65a as the first discharge port, and the airflow for cooling the developing device 4A is discharged from the discharge port (opening of the cooling duct) 65b as the second discharge port. Will be done. Specifically, the duct 53 is connected to the discharge port 65a, and the cooling duct 55 is connected to the discharge port 65b, and the respective airflow paths to the discharge port are different.

That is, as shown by the broken line arrow in FIG. 8, the airflow sucked from the suction opening 51 moves to the downstream side in the longitudinal direction as it is, and then the first development is performed from the front side to the back side of the developing device 4A by the duct 53. It moves on the lower side of the agent transport path 45a (see FIG. 6 and the like). Then, as shown in FIG. 14, the airflow is discharged from the discharge port 65a of the airflow discharge unit 57A installed on the back side of the developing device 4A. On the other hand, the airflow sent from the inflow opening 54 by the cooling fan 67 is discharged as it is from the discharge port 65b of the airflow discharge part 57A through the cooling duct 55 provided on the back surface of the developing device 4A.

The two outlets 65a and 65b are formed so as to be adjacent to each other. Here, when two outlets are adjacent to each other, for example, the length of one side of a square having an area where the distance between the two outlets is equal to the smaller area of the opening areas of the two outlets. It is a case where the length is 50% or less, 10% or less, and further 5% or less. In this case, even if there is a protrusion such as a rib between the two outlets, a recess, or a hole that does not lead to any of the first and second airflow spaces, it is assumed that they are adjacent to each other.

Adjacent two outlets include not only the case where the two outlets are open in the same plane but also the case where the two outlets are open in different planes. The different planes are, for example, parallel to each other but deviated in the flow direction of the air flow, or one plane is inclined with respect to the other. In the present embodiment, the two discharge ports 65a and 65b are opened in the same plane of the developing side connecting portion 59A.

Similar to the first embodiment, the developing side connecting portion 59A is connected to the main body side connecting portion 58 provided on the main body side. The main body side connection portion 58 is formed with one suction port 60 for sucking the airflow exhausted from the two discharge ports 65a and 65b. The suction port 60 is formed at a position overlapping the two discharge ports 65a and 65b when the main body side connection portion 58 is connected to the development side connection portion 59A, and the airflow discharged from the two discharge ports 65a and 65b is once discharged. Inhale to. Also in this embodiment, a sealing material 66 such as urethane foam is arranged around the suction port 60 of the main body side connection portion 58.

There is no problem if the suction port 60 and the discharge ports 65a and 65b overlap with each other if the suction port 60 covers about 80% or more of the total area of the discharge ports 65a and 65b, but 90% or more or the suction port. It is more preferable that 60 covers the entire discharge ports 65a and 65b. FIG. 15 is a schematic view showing the degree of overlap between the suction port 60 and the discharge ports 65a and 65b. As shown in FIG. 15, in the present embodiment, the opening area of the suction port 60 is larger than the total area of the discharge ports 65a and 65b. Then, when the main body side connecting portion 58 is joined to the developing side connecting portion 59A, the suction port 60 covers the entire discharge ports 65a and 65b.

Specifically, the suction opening 51 is trapezoidal with a base of 9.2 [mm], an upper side of 5.2 [mm], and a height of 5.9 [mm], and the inflow opening 54 is 10.5 [. It is a rectangle of mm] × 20.1 [mm], and the discharge opening 56 is a rectangle of 10.5 [mm] × 15 [mm]. The discharge port 65a is a rectangle of 12.5 [mm] × 17.3 [mm], and the discharge port 65b is a rectangle of 19.2 [mm] × 15.9 [mm]. Further, the two discharge ports 65a and 65b are arranged at a distance of 2 mm from each other. Further, the suction port 60 is a rectangle of 36 [mm] × 17 [mm].

Also in the case of this embodiment, the airflow containing the scattered toner delivered to the suction port 60 on the main body side and the airflow for cooling the developing device 4A sucked from the inflow opening 54 are the same suction fan 70 (FIG. 7) passes through the exhaust duct 71 in the main body together. Then, the toner is discharged to the outside of the machine through the provided toner filter (not shown). The suction fan 70 is installed downstream of the toner filter. In the present embodiment, both the suction fan 70 and the cooling fan 67 (FIG. 7) for letting the air flow into the inflow opening 54 use a sirocco fan.

Also in the case of the present embodiment as described above, by adopting the above configuration, in the developing apparatus provided with both the airflow space 52 for collecting the scattered toner and the cooling duct 55 for cooling the developing apparatus 4A. However, it is possible to suppress the increase in size of the device. Further, in the present embodiment, the above-mentioned two airflows are discharged by the two discharge ports 65a and 65b, respectively. Therefore, even in the configuration having the cooling fan 67 that sends the airflow to the cooling duct 55, the airflow pushed by the cooling fan 67 flows back through the duct 53 toward the suction opening 51 in the airflow discharge portion 57A. Can be suppressed.

In the above description, the number of suction ports 60 for sucking airflow from the two discharge ports 65a and 65b is one, but the number of suction ports 60 may be two. That is, the suction ports may be connected to the two discharge ports 65a and 65b, respectively. In this case, for example, it may be configured to have an opening that covers the entire two discharge ports 65a and 65b, and to partition the inside of the opening by a wall. This wall may be arranged over the entire area of the exhaust duct 71, or may be arranged only within a predetermined distance from the opening.

[Example]
Next, the experimental results of investigating the direction of the air flow in the suction opening 51 will be described in Example 1 satisfying the configuration of the first embodiment and Example 2 satisfying the configuration of the second embodiment. In the experiment, the direction of the air flow of the suction opening 51 when the air volume (DUTY) of the suction fan 70 connected to the suction port 60 on the main body side was shaken under the condition that the cooling fan 67 was driven with a constant air volume was investigated. .. The suction fan 70 is a sirocco fan driven by a 24V power supply. The results are shown in Table 1.

表１において、「外」と記載しているものはダクト５３を逆流し、吸引開口部５１から外に気流が出ていく場合を示し、「内」と記載しているものはダクト５３を気流が吸引開口部５１から内に向かって流れていく場合を示している。「内」と「外」の判定は、吸引開口部５１近傍に線香を置いた時の流れの向きで判定した。

In Table 1, the case described as "outside" indicates the case where the duct 53 flows backward and the airflow flows out from the suction opening 51, and the case described as "inside" indicates the case where the duct 53 is airflowed. Shows the case where is flowing inward from the suction opening 51. The determination of "inside" and "outside" was made based on the direction of flow when the incense stick was placed in the vicinity of the suction opening 51.

As is clear from Table 1, in the first embodiment, when the DUTY of the suction fan 70 is lowered, the balance of the air flow is lost at the suction port 60, the duct 53 flows backward, and the air flow flows out from the suction opening 51. I found out that I would go. On the other hand, in Example 2, when the DUTY of the suction fan 70 is lowered, the tendency of backflow is the same, but the threshold value is improved from 40% to 20%, and it is found that the problem of backflow is suppressed. ..

<Third embodiment>
The third embodiment will be described with reference to FIGS. 16 to 19. In the present embodiment, the outputs of the suction fan 70 and the cooling fan 67 are controlled in the configurations of the first and second embodiments described above. Since other configurations and operations are the same as those of the first embodiment or the second embodiment described above, the same reference numerals are given to the same configurations, and the description and illustration are omitted or simplified. The description will focus on the parts different from the embodiment or the second embodiment.

First, it is conceivable to use one suction fan in order to generate an air flow for collecting the scattered toner and an air flow for cooling the developing device 4A in the developing device 4A. However, if one fan tries to generate these two airflows, the fan will become large. Therefore, in the present embodiment, as described in the first and second embodiments described above, two fans (suction fan 70 and cooling fan 67) are used to generate the above-mentioned two airflows. There is.

However, as will be described in detail later, the output of at least one of the suction fan 70 and the cooling fan 67 may be reduced depending on the environment around the developing device. When the outputs of the suction fan 70 and the cooling fan 67 are driven at full throttle, for example, the power consumption increases and the noise increases. Therefore, it is desired to suppress power consumption and noise by controlling the output of the fan according to the environment around the developing device. Therefore, in the present embodiment, the outputs of the suction fan 70 and the cooling fan 67 are controlled according to the environment around the developing device.

FIG. 16 shows a block diagram relating to output control of the suction fan 70 and the cooling fan 67 of the present embodiment. The control unit 200 controls the output of the suction fan 70 and the cooling fan 67, as well as the entire image forming apparatus 100. Such a control unit 200 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU controls each part while reading a program corresponding to the control procedure stored in the ROM. Further, work data and input data are stored in the RAM, and the CPU controls by referring to the data stored in the RAM based on the above-mentioned program or the like. Hereinafter, the output control of the suction fan 70 and the cooling fan 67 by the control unit 200 will be described.

As shown in FIG. 16, the developing apparatus 4A (4B, 4C, 4D) has a developing sleeve 44a, a cooling duct 55, an airflow space 52, and the like. The image forming apparatus according to the present embodiment includes a cooling fan 67 that sends an air flow to the cooling duct 55, and a suction fan 70 that sucks the air flow of the cooling duct 55 and the airflow space 52. Further, in the case of the present embodiment, a temperature / humidity sensor 201 for detecting the temperature and humidity around the developing device 4A is provided outside the developing container 41. The temperature / humidity sensor 201 as the temperature detecting means and the humidity detecting means detects the temperature / humidity around the developing device 4A, and the control unit 200 determines the operation of the cooling fan 67 and the suction fan 70 based on the detection result.

Here, in the developing apparatus, when the charge amount of the toner becomes low, the electrostatic adhesion force of the toner in the developing agent to the carrier weakens, the toner easily peels off from the carrier, and the amount of toner scattered increases. Therefore, the amount of scattered toner depends on the amount of charge of the toner (hereinafter referred to as Q / M). Further, since the Q / M of the toner changes depending on the humidity around it, the Q / M depends on the humidity around the developing device. The humidity dependence of Q / M and the Q / M dependence of the amount of scattered toner are shown in FIGS. 17 (a) and 17 (b), respectively.

FIG. 17A shows the results of measuring the toner scattered from the developing sleeve 44a by circulating the developer containing the toner adjusted to a plurality of Q / Ms in the developing apparatus of the present embodiment by the following method. .. First, a line laser is irradiated to approximately the center of the developing sleeve 44a. The line laser is created by scattering in a certain direction with a cylindrical lens so that the line laser is irradiated in a line shape having a constant line width. Scattered toner flying on the optical path of the line laser scatters the laser beam. Therefore, by observing from a direction substantially perpendicular to the irradiation direction of the line laser, it is possible to measure the number and loci of the scattered toner existing in the area irradiated with the laser.

As the line laser, a YAG laser manufactured by Nippon Laser Co., Ltd. was used as a light source, and a cylindrical lens was adjusted so that the line width was 0.5 mm and irradiated. For observation, a high-speed camera SA-3 manufactured by Photron is used, and the set values (frame rate and exposure time) of the high-speed camera and the optical system (lens, etc.) are appropriately selected so that the scattered toner on the line laser can be observed. bottom. By the above method, the number of scattered toners from the developing device was measured for each toner charge amount of the developer.

FIG. 17B shows the results of measuring the Q / M of the toner left at a plurality of temperatures and humidity for 72 hours. The toner charge amount Q / M was measured using an electric field separation type charge amount measuring device manufactured by Etowasu Co., Ltd. in an environment of room temperature of 23 ° C. and humidity of 50%.

As shown in FIG. 17B, Q / M depends on humidity, and as shown in FIG. 17A, the amount of toner scattered depends on Q / M. That is, in an environment where the humidity is high and the Q / M is low, the toner tends to scatter. Therefore, in an environment with high humidity, it is desired to increase the output of the suction fan 70 that collects the scattered toner and to suck the scattered toner rapidly.

On the other hand, when the periphery of the developing apparatus is exposed to a high temperature, the developing agent melts and accumulates in the developing container 41. The accumulated lump of toner may be conveyed to the developing sleeve 44a and developed on the photosensitive drum 1A. The developed lump of toner becomes a stain-like shape on the image and is output, resulting in an image defect. In order to prevent image defects due to the above-mentioned temperature rise, it is desirable to strengthen the movement of the cooling fan 67 to cool the developing container 41 when the temperature around the developing container 41 becomes high.

Therefore, in the present embodiment, the output ratio of the cooling fan 67 and the suction fan 70 provided outside the developing container 41 is adjusted according to the environment, and the air volume generated from the cooling fan 67 and the suction fan 70 are generated. I try to adjust the suction amount. Specifically, the control unit 200 sets the output of the cooling fan 67 as the first cooling output when the temperature detected by the temperature / humidity sensor 201 is the first temperature. On the other hand, when the temperature detected by the temperature / humidity sensor 201 is the second temperature higher than the first temperature, the control unit 200 sets the output of the cooling fan 67 as the second cooling output larger than the first cooling output. That is, the control unit 200 controls so that the output of the cooling fan 67 increases as the ambient temperature of the developing device 4A increases, so that the temperature rise of the developing agent in the developing device 4A is suppressed.

On the other hand, the control unit 200 sets the output of the suction fan 70 as the first suction output when the humidity detected by the temperature / humidity sensor 201 is the first humidity. On the other hand, when the humidity detected by the temperature / humidity sensor 201 is the second humidity higher than the first humidity, the control unit 200 sets the output of the suction fan 70 as the second suction output larger than the first suction output. That is, the control unit 200 controls so that the higher the humidity around the developing device 4A, the higher the output of the suction fan 70, thereby suppressing the scattering of toner from the inside of the developing device 4A.

When the output of the cooling fan 67 exceeds the output of the suction fan 70, air leaks from the developing device 4A, and the toner scatters in the image forming device when it hits, for example, a photosensitive drum or a developing device containing a developer of another color. There is a risk of polluting the cabin. For example, when the cooling fan 67 and the suction fan 70 are the same fan, such a problem may occur if the output of the cooling fan 67 is higher. However, in reality, not only the output of the fan but also the length of the path through which the airflow flows and the pressure loss have an effect. Therefore, in consideration of these factors, the airflow from the cooling fan 67 should not flow back toward the airflow space 52. In addition, it is preferable to control the outputs of the two fans.

In the present embodiment, the temperature and humidity around the developing device 4A are detected by the temperature and humidity sensor 201, and the outputs of the two fans, the cooling fan 67 and the suction fan 70, = the number of rotations, based on the environment table determined by the temperature and humidity environment. I try to switch the ratio of. An example of the environment table is shown in FIG.

In the example of FIG. 18, the cooling fan 67 and the suction fan 70 are used at 1000 rpm with an output of 100%. Further, "A" shown in FIG. 18 indicates the output of the cooling fan 67, and "B" indicates the output of the suction fan 70. Further, in the environment table shown in FIG. 18, the output DUTY of the cooling fan 67 and the suction fan 70 is changed according to the temperature and humidity. Further, if the output of the cooling fan 67 exceeds the suction fan 70, air may leak from the developing device. Therefore, the output DUTY prevents the output of the cooling fan 67 into which the airflow is pushed from exceeding the suction fan 70. From the above, when the output of the cooling fan 67 is A and the output of the suction fan 70 is B, it is desirable that the ratio of A and B is 0 <A / B ≦ 1.0.

The output shown in FIG. 18 forms 40,000 A4 images with an image DUTY of 50% in each environment, and whether or not the output image has roller stains, which are image stains that cause scattering, and stain images, which are caused by temperature rise. It is decided by confirming.

For example, when the humidity is 80% and the temperature is 40 ° C., the risk of toner scattering and stains increases. Therefore, the output DUTY of the cooling fan 67 and the suction fan 70 is set to 100% to maximize the suction power of the scattered toner. , The developing device 4A is positively cooled.

Further, when the humidity is 20% and the temperature is 20 ° C., it is not necessary to actively perform cooling and the risk of toner scattering is low, so that the output DUTY of the cooling fan 67 and the suction fan 70 is weakened. In this way, by operating with the output DUTY of the cooling fan 67 and the suction fan 70, which are optimal depending on the temperature and humidity around the developing device 4A, noise and power consumption can be appropriately suppressed. The output shown in FIG. 18 is an example, and the output may be changed depending on the physical characteristics of the toner and the specifications of the fan used.

FIG. 19 shows an example of a flowchart for controlling the output of the cooling fan 67 and the output of the suction fan 70 in the present embodiment. As shown in FIG. 19, for example, the control unit 200 receives an image forming job and starts controlling the fan from the timing when the drive of the developing device is turned on (S1). The image formation job is a period from the start of image formation to the completion of image formation based on the print signal (image formation signal) that forms an image on the recording material. That is, the image forming job performs a series of operations of a pre-operation (forward rotation) performed before the image forming operation, an image forming operation, and a post-operation (rear rotation) performed after the image forming operation by inputting the image forming signal. The period.

Temperature and humidity around each of the four color developing devices at the timing when the development drive is stopped at the end of each image formation (rear end of the image) after the start of driving of the developing device and at the end of post-rotation including adjustment control. The sensor 201 starts measuring the temperature and humidity (S2). The outputs of the cooling fan 67 and the suction fan 70 are controlled (S4) with reference to the environment table shown in FIG. 18 according to the measurement result of the temperature / humidity sensor 201 (S3). After that, if the image formation job is completed, the image formation is completed (S5).

[Example]
The following experiments were conducted to confirm the effect of this embodiment. The experiment was carried out in a state where four developing devices of Comparative Example and four developing devices of Example 3 satisfying the present embodiment were placed at the mounting positions of the developing devices 4A to 4D in the image forming apparatus 100. The configuration of the comparative example is, for example, the configuration described in JP-A-2018-180267. That is, the opening areas of the two discharge ports of each of the scattering suction and cooling paths are changed by rotating the semicircular member, and the mode in which the scattering suction is prioritized and the mode in which the cooling is prioritized are switched.

Further, in the experiment, 40,000 A4 images having an image DUTY of 50% were formed, and it was confirmed whether or not the output image had roller stains which are image stains which cause scattering and stain images which are caused by temperature rise. The environment was performed in a laboratory with a temperature and humidity of 30 ° C., 80% and 10 ° C., 80%.

Further, the outputs of the cooling fan 67 and the suction fan 70 in Example 3 are the rotation speed A of the cooling fan 67 = 1000 rpm and the rotation speed of the suction fan 70 B = 1000 rpm (A / B =) in an environment of 30 ° C. and 80%. It was set as 1). Further, in an environment of 10 ° C. and 80%, the rotation speed of the cooling fan 67 was set to A = 200 rpm, and the rotation speed of the suction fan 70 was set to B = 1000 rpm (A / B = 0.2).

In the developing device of the comparative example, the area ratio of the cooling discharge port and the scattering discharge port is adjusted by a shutter. In an environment of 30 ° C. and 80%, the area ratio C / D of the cooling discharge port area C and the scattering discharge port D was set to 1. Further, in an environment of 10 ° C. and 80%, the area ratio C / D of the cooling discharge port area C and the scattering discharge port D was set to 0.2.

以上のように、比較例に対し、実施例３を用いることでシャッター構成を用いることなく、飛散起因のローラ汚れと昇温起因のシミ画像が良好となる事が分かった。 The experimental results are shown in Tables 2 and 3 below.

As described above, it was found that by using Example 3 as compared with Comparative Example, the roller stain caused by scattering and the stain image caused by temperature rise were improved without using the shutter configuration.

<Other embodiments>
In each of the above-described embodiments, as a developing apparatus, a developer is supplied from the second developer transport path (second chamber) 45b to the developing sleeve (developer carrier) 44a, and the first developer transport path (first). The configuration for recovering the developer from the developing sleeve 44a in the room 45a has been described. However, the developer may be supplied from the second chamber to the developer carrier, and the developer may be recovered from the developer carrier in the second chamber. In addition to the configuration in which the first chamber and the second chamber are arranged vertically, the developing apparatus has a configuration in which the first chamber and the second chamber are arranged so as to be adjacent in the horizontal direction or in a direction inclined in the horizontal direction. There may be.

The image forming apparatus of the present invention can be applied to a copying machine, a printer, a facsimile, a multifunction device having a plurality of these functions, and the like.

1A, 1B, 1C, 1D ... Photosensitive drum (image carrier) / 3A, 3B, 3C, 3D ... Laser scanner (exposure device) / 4A, 4B, 4C, 4D, ... Developer / 41・ ・ ・ Development container / 41a ・ ・ ・ Upstream end / 44a ・ ・ ・ Development sleeve (development rotating body) / 45a ・ ・ ・ First developer transfer path (collection chamber) / 45b ・ ・ ・ Second developer Transport path (supply chamber) / 46a ... 1st screw (second transport screw) / 46b ... 2nd screw (first transport screw) / 48 ... protruding part (toner receiving part) / 52・ ・ ・ Airflow space part / 53 ・ ・ ・ Duct / 55 ・ ・ ・ Cooling duct / 57 ・ ・ ・ Airflow discharge part / 65 ・ ・ ・ Discharge port (opening) / 65a ・ ・ ・ Discharge port (opening) / 65b ... Discharge port (opening) / 67 ... Cooling fan / 70 ... Suction fan / 100 ... Image forming device / 220 ... Drive device / 221 ... Drive transmission member

Claims (5)

Image carrier and
An exposure apparatus that exposes the image carrier to form an electrostatic latent image on the image carrier.
A developing container containing a developer containing a toner and a carrier, a developing rotating body that carries and conveys the developer to a developing position for developing an electrostatic latent image formed on the image carrier, and the image of the developing container. A driving force transmitting member arranged on the side facing the carrier and one end side in the direction of the rotating axis of the developing rotating body and transmitting the driving force for rotationally driving the developing rotating body to the developing rotating body. With a developing device
A driving device arranged on the side of the developing container facing the image carrier and one end side in the direction of the rotation axis of the developing rotating body to apply the driving force to the driving force transmitting member.
To collect the toner scattered from the developing rotating body, which is arranged on the side of the developing container facing the image carrier and is formed from one end side to the other end side in the rotation axis direction of the developing rotating body. Air flow space, which is the air flow path of
One end side of the developing rotating body in the direction of the rotation axis and the side of the developing container facing the image carrier and the side of the developing container facing the image carrier. Is a duct formed over the opposite side and connected to the airflow space so that airflow can flow between the airflow space and the airflow space.
The opening of the duct is arranged on the side of the developing container opposite to the side facing the image carrier and on one end side of the developing rotating body in the direction of the rotation axis to generate airflow in the airflow space. With a suction fan for sucking air from
An image forming apparatus comprising. For cooling the developing container, which is arranged on the side of the developing container opposite to the side facing the image carrier and formed from one end side to the other end side in the rotation axis direction of the developing rotating body. Further equipped with a cooling duct for forming an air flow path,
The image forming apparatus according to claim 1, wherein an air flow is generated in the cooling duct when the suction fan sucks air from the opening of the cooling duct. For cooling the developing container, which is arranged on the side of the developing container opposite to the side facing the image carrier and formed from one end side to the other end side in the rotation axis direction of the developing rotating body. Further equipped with a cooling duct for forming an air flow path,
The cooling duct joins the duct on the side of the developing container opposite to the side facing the image carrier and on one end side of the developing rotating body in the direction of the rotation axis.
The image formation according to claim 1, wherein the suction fan sucks air from the opening of the duct to generate airflow in the airflow space and generate airflow in the cooling duct. Device. The developing apparatus is arranged below the developing position and includes a toner receiving portion for receiving toner scattered from the developing rotating body.
Any one of claims 1 to 3, wherein the flow path of the airflow space portion is a space surrounded by the developing container, the toner receiving portion, the developing rotating body, and the image carrier. The image forming apparatus according to. The developing apparatus includes a supply chamber for supplying a developing agent to the developing rotating body, a collecting chamber for collecting the developing agent that has passed through the developing position from the developing rotating body, and the developing chamber from the collecting chamber to the supplying chamber. A first series of communication sections that communicate the recovery chamber and the supply chamber so that the agent moves, and a first series that communicates the supply chamber and the recovery chamber so that the developer moves from the supply chamber to the recovery chamber. The double communication section, the first transport screw arranged in the supply chamber and transporting the developer in the first direction from the first series communication section to the second communication section, and the first transfer screw arranged in the recovery chamber, said. Further, it has a second transport screw for transporting the developer in the second direction from the second communication portion to the first series communication portion.
The other end side of the developing rotating body in the rotation axis direction is the upstream side in the first direction from the image forming region where an image can be formed on the image carrier.
The image forming apparatus according to any one of claims 1 to 4, wherein one end side of the developing rotating body in the rotation axis direction is a downstream side in the first direction from the image forming region.

Images