JP6547597B2 - Image forming device - Google Patents

Description

  The present invention relates to an image forming apparatus.

2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus that forms an image on a sheet using toner is known.
In such an image forming apparatus, the toner may be scattered or leaked in each process of development, transfer, and cleaning, and the apparatus and the sheet may be soiled. There is
For example, Patent Document 1 discloses an image forming apparatus provided with a toner collection unit that suctions scattered toner generated in a developing unit by a suction duct and centrifuges the toner by a cyclone unit and collects toners that can not be centrifuged by a filter. Is disclosed.

JP, 2012-27285, A

  However, in the configuration of Patent Document 1, the pressure loss of the filter increases as the amount of toner attached to the filter increases, so that the suction air velocity decreases, which in turn causes the inlet velocity of the inlet of the cyclone unit to decrease, resulting in separation efficiency. The problem is that the filter life decreases as a result.

Therefore, it is conceivable to increase the air volume of the fan that generates the flow of air from the suction duct to the filter in order to improve the suction air velocity, but in this case, the toner on the developing roller is sucked to It will accelerate the increase. In addition, if the air volume of the fan is increased in a state where toner adheres to the filter, the wind speed passing through the filter is increased, which may cause the toner to pass through the filter and be discharged to the outside of the apparatus.
In addition, although the air velocity can be increased by narrowing the inlet area of the cyclone unit, in this case, the air velocity of the suction duct is lowered and the suction performance of the scattered toner is lowered.

  The present invention has been made in view of such problems, and provides an image forming apparatus capable of suppressing a drop in suction air velocity and extending a filter life without causing toner discharge to the outside of the machine. The purpose is

In order to solve the above problems,
According to one aspect of the invention,
In an image forming apparatus for forming an image on a sheet,
A duct portion for suctioning toner-containing air containing toner;
A shielding member for changing the opening area of the inlet of the duct portion;
A cyclone unit in communication with the duct unit for centrifugally separating the toner from the toner-containing air;
A recovery unit that recovers the toner separated by the cyclone unit;
A filter unit for passing air after the toner is separated by the cyclone unit;
A fan for generating a flow of the toner-containing air from the duct portion to the filter portion;
A control unit configured to increase an air volume of the fan as the amount of toner collected by the collection unit increases and to narrow an opening area of the duct unit by the shielding member;
And the like.

  According to the present invention, it is possible to suppress a drop in suction air velocity and extend the filter life without causing toner discharge to the outside of the machine.

FIG. 1 is a schematic view showing an entire configuration of an image forming apparatus. FIG. 2 is a functional block diagram showing a control configuration of the image forming apparatus. FIG. 5 is a schematic view for explaining a toner recovery mechanism. It is the top view seen from the direction of arrow A in FIG. 5 is a flowchart showing a procedure of toner recovery processing. (A) is a figure which shows the change of the air volume in a suction duct, a cyclone part, and a filter part, (b) is a figure which shows the change of the wind speed in a suction duct, a cyclone part, and a filter part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated example.

[1. Overall Configuration of Image Forming Apparatus]
First, the overall configuration of the image forming apparatus in the present embodiment will be described.
FIG. 1 is a schematic view showing the entire configuration of the image forming apparatus 1. FIG. 2 is a functional block diagram showing a control configuration of the image forming apparatus 1.

  As shown in FIG. 1, the image forming apparatus 1 forms an image on a sheet by electrophotography, and has four colors of yellow (Y), magenta (M), cyan (C), and black (K). Is a tandem type color image forming apparatus in which toners of

  The image forming apparatus 1 includes, for example, a sheet storage unit 10, an image reading unit 20, an image forming unit 30, a fixing unit 40, a control unit 50, a storage unit 60, an operation display unit 70, and a toner collection mechanism. There are 100 and.

  The sheet storage unit 10 is disposed in the lower part of the image forming apparatus 1, and is provided with a plurality of trays 11 corresponding to the size and type of sheets. The sheet is fed from the tray 11 and sent to the conveyance unit 12, and is conveyed by the conveyance unit 12 to the image forming unit 30 and the fixing unit 40.

  The image reading unit 20 reads an image of a document conveyed by a document conveyance unit (not shown) or an image of a document placed on the document table 21 and generates image data. Further, the image reading unit 20 performs processing such as shading correction, dither processing, compression and the like on the image data generated by A / D conversion, and stores the processed data in the RAM of the control unit 50 described later. The image data is not limited to the data output from the image reading unit 20, and may be received from an external device such as a personal computer connected to the image forming apparatus 1 or another image forming apparatus.

The image forming unit 30 forms an image on a sheet based on an image forming job (hereinafter simply referred to as a “job”).
The image forming unit 30 includes four sets of image forming units 30Y, 30M, 30C, and 30K corresponding to Y, M, C, and K color components, an intermediate transfer belt 33, and a transfer roller 34, respectively. There is.

  The image forming units 30Y, 30M, 30C, and 30K respectively include a drum-shaped photosensitive member 31, a developing unit 32 disposed around the photosensitive member 31, and a charging unit, an exposure unit, and a cleaning unit (not shown). Have a department.

An electrostatic latent image is formed on the photosensitive member 31 by the exposure unit irradiating the photosensitive member 31 to be charged with laser light. The developing unit 32 is formed on the photosensitive member 31 by supplying toner of a predetermined color (any one of Y, M, C, and K) by the developing roller 32 a charged on the exposed photosensitive member 31. Develop the electrostatic latent image.
The images (monochromatic images) formed by the toners of Y, M, C, and K on the four photoconductors 31 corresponding to Y, M, C, and K, respectively, are formed on the intermediate transfer belt 33 from the respective photoconductors 31. Are sequentially superimposed and transferred. Thus, toner images having Y, M, C, and K as color components are formed on the intermediate transfer belt 33. The intermediate transfer belt 33 is an endless belt wound around a plurality of transport rollers, and rotates according to the rotation of each transport roller. Then, by applying a bias of reverse polarity to the toner to the transfer roller 34, the toner image formed on the intermediate transfer belt 33 is transferred onto the sheet.

  In the present embodiment, a toner recovery mechanism 100 for recovering the scattered toner in the four image forming units 30Y, 30M, 30C, and 30K as described above is provided. Details of the toner recovery mechanism 100 will be described later.

  The fixing unit 40 includes a pair of rollers including a heating roller and a pressure roller. Heat and pressure are applied to the sheet by passing through the nip portion of the pair of rollers, and the toner image transferred onto the sheet is fused and fixed.

  The control unit 50 is configured of, for example, a central processing unit (CPU), a random access memory (RAM), and the like. The CPU of the control unit 50 reads various programs such as system programs and processing programs stored in the storage unit 60, expands them in the RAM, and executes various processes such as image forming processing and toner collection processing according to the expanded programs. Run. Details of the toner collection process will be described later.

The storage unit 60 is configured of, for example, a hard disk drive (HDD), a nonvolatile memory of a semiconductor, or the like.
The storage unit 60 stores various programs including a system program and a processing program executed by the control unit 50, and data necessary for executing these programs.

  The operation display unit 70 includes a display screen, a display unit that displays various information on the screen, and an operation unit used to input various instructions from the user.

[2. Configuration of Toner Collection Mechanism]
Next, the configuration of the toner recovery mechanism 100 will be described.
FIG. 3 is a schematic view for explaining the toner recovery mechanism 100. As shown in FIG. 4 is a top view seen from the direction of arrow A in FIG.
In addition, in FIG. 3, in order to demonstrate the flow of air, the suction duct 111 is shown more largely than actual, and illustration of the common duct 113 is abbreviate | omitted.

  The toner recovery mechanism 100 separates the toner from the toner-containing air, and the duct portion 110 which forms an air passage for passing the toner-containing air containing the toner scattered by the image forming units 30Y, 30M, 30C, and 30K of the image forming unit 30. , And a toner collection unit 120 for collecting (see FIG. 2).

[2-1. Configuration of duct section]
The duct unit 110 includes a suction duct 111 disposed for each of the four image forming units 30Y, 30M, 30C, and 30K, and a common duct 113 for integrating the suction ducts 111.

The suction duct 111 is disposed on the upper side of each developing unit 32 of the image forming units 30Y, 30M, 30C, and 30K.
The inlet 111a of each suction duct 111 is located in the vicinity of the photosensitive member 31 and the developing roller 32a, and suctions the toner scattering around the photosensitive member 31 and the developing roller 32a.

As shown in FIG. 3, a shielding member 112 is provided inside the suction duct 111.
The shielding member 112 is provided, for example, on the inner upper surface of the suction duct 111.
Further, the shielding member 112 is provided with, for example, a drive unit such as a gear or a solenoid, and when the drive unit is driven under the control of the control unit 50, the shielding member 112 projects downward on the inner upper surface of the suction duct 111 The cross-sectional area of the inflow port 111a of 111 is narrowed.

  The shielding member 112 preferably has a shape that guides the toner-containing air in a direction different from the direction toward the developing roller 32 a of the developing unit 32. For example, any shape may be used as long as the protrusion is not formed at a portion facing the developing roller 32 a and is flat. If a projecting portion is formed at a position facing the developing roller 32a of the shielding member 112 (two-dot chain line in FIG. 3), the sucked air hits the projecting portion and the air flows toward the developing roller 32a ( Arrow W2 in FIG. On the other hand, if the position of the shielding member 112 facing the developing roller 32a is flat, it is possible to prevent the direction of the wind generated when sucking the scattered toner from being directed to the developing roller 32a (arrow W1 in FIG. 3). .

  The common duct 113 is formed in a hollow rectangular shape extending in the vertical direction, and has a function of guiding the toner-containing air to the toner collection unit 120 and a receiving unit that can detachably attach the toner collection unit 120 to the duct unit 110. It has a role (see Figure 2).

  The common duct 113 has four communication ports to which the suction duct 111 can be connected on the side facing the four image forming units 30Y, 30M, 30C, and 30K, and the four image forming units 30Y, 30M, 30C, and 30K A connection port 113A for connecting the inflow port 121 of the toner collection unit 120 is provided on the opposite side to the opposite side.

As shown in FIG. 3, a second shielding member 114 is provided inside the connection port 113A.
The second shielding member 114 is provided, for example, on the inner lower surface of the connection port 113A.
The second shielding member 114 is provided with a driving unit such as a gear or a solenoid, for example, and when the driving unit is driven by the control of the control unit 50, the second shielding member 114 is upward on the inner lower surface of the connection port 113A. To narrow the cross-sectional area of the connection port 113A.

The second shielding member 114 preferably has a shape that guides the toner-containing air in a direction along a tangent L1 of a cyclone unit 122 described later. When configured in this manner, the direction of the air generated when suctioning the scattered toner follows the tangent L1 of the cyclone unit 122 (arrow W1 in FIG. 4), as compared with the case where it is not so (arrow in FIG. 4). W2) The centrifugal force in the cyclone unit 122 is increased, and the separation efficiency can be improved.
The second shielding member 114 preferably has a shape that guides the toner-containing air in a direction toward the top of the cyclone portion 122. For example, it may be a shape that protrudes upward as it goes from the suction duct 111 side to the cyclone unit 122. When configured in this manner, the direction of the wind generated when suctioning the scattered toner is directed to the upper part of the cylindrical cyclone portion 122 (arrow W1 in FIG. 3), as compared with the case where it is not so (FIG. 3). Arrow W2), the separation distance becomes long, and the separation efficiency can be increased.

[2-2. Configuration of Toner Collection Unit]
The toner collection unit 120 is configured to be attachable to and detachable from the common duct 113.
The toner collection unit 120 includes an inlet 121, a cyclone unit 122 communicating with the inlet 121, a recovery unit 123, a reversing unit 124, an air flow passage unit 125, a filter unit 126, and a filter unit 126. A dirt detection sensor 127 for detecting the degree of clogging, an outlet 128, a wind speed sensor 129 for detecting a wind speed near the outlet 128, and a fan F for generating a flow of air are provided.

The inlet 121 is a receiving port for receiving the toner-containing air that has passed through the duct portion 110.
When the toner collection unit 120 is attached to the common duct 113, the inlet 121 faces the connection port 113 A of the common duct 113. Thus, the cyclone unit 122 is in communication with the common duct 113 via the inlet 121.

  The cyclone unit 122 is in communication with the internal space of the common duct 113 and centrifuges the toner from the toner-containing air. The cyclone portion 122 is formed in a cylindrical shape, and its axis coincides with the vertical direction (the direction in which gravity acts). As described above, the arrangement in which the axes are aligned in the vertical direction is the optimum arrangement for separating the toner from the air.

The toner-containing air that has entered the cyclone unit 122 travels in the tangential direction of the inner periphery of the cyclone unit 122. As a result, a swirling flow in which air swirls is generated inside the cyclone unit 122.
Most of the toner in the swirling flow is separated (centrifuged) from the air because the toner moves radially due to the centrifugal force exerted by the circular movement of the object. The separated toner drops downward by its own weight and is stored in the collection unit 123. On the other hand, air enters the reversing unit 124 provided above the cyclone unit 122.

  The reversing portion 124 is formed in a U-shaped pipe shape, and vertically inverts the air from the cyclone portion 122 and guides the air to the air flow path portion 125.

  The air flow passage 125 communicates with the reversing unit 124 and guides the air flowing from the cyclone unit 122 via the reversing unit 124 downward. A filter unit 126 that filters the toner is disposed in the air flow passage unit 125.

The filter unit 126 is for collecting a small amount of toner contained in the air having passed through the cyclone unit 122, and the air having passed through the filter unit 126 is thus cleaned.
It is preferable to arrange a plurality of the filter portions 126 in a direction in which the air passes, since the air cleaning effect is increased. For example, as the filter unit 126, the toner dustproof filter unit 126a, the ozone catalyst filter unit 126b, and the toner dustproof filter unit 126c are arranged from the cyclone unit 122 side.

The dirt detection sensor 127 is disposed at a position facing the side portion of the toner dust filter portion 126c, and detects the degree of clogging (dirt) of the toner dust filter portion 126c.
As the dirt detection sensor 127, for example, a photosensor having a light emitting element and a light receiving element can be used. The dirt detection sensor 127 is not limited to the photosensor, and may be, for example, a sensor that recognizes the state of the filter in an image using an imaging device and detects the degree of clogging. Alternatively, without using the stain detection sensor 127, a transparent window may be formed, and the toner dust filter portion 126c may be visually observed from the transparent window to check the degree of clogging (dirt) of the toner dust filter portion 126c.

The outlet 128 is provided on the opposite side of the air flow passage portion 125 to the cyclone portion 122 side.
The outlet 128 faces the fan F, and the air having passed through the filter portion 126 flows out from the outlet 128 toward the fan F.

  The wind speed detection sensor 129 is a so-called anemometer and is disposed in the vicinity of the outlet 128 to detect the wind speed of the air flowing through the outlet 128.

  The fan F is disposed above the outlet 128. The fan F causes air to flow from the duct portion 110 to the toner collection portion 120. That is, the air sucked by the suction duct 111 passes through the common duct 113, the cyclone unit 122, the reversing unit 124, the air passage unit 125, the filter unit 126, and the outlet 128, and then passes through the fan F as well. The air is exhausted to the outside of the image forming apparatus 1.

  Further, on the surface opposite to the surface on which the inflow port 121 of the toner collection unit 120 is provided, a handle 120a is provided which is gripped when the toner collection unit 120 is attached to and detached from the common duct 113.

[3. Operation of image forming apparatus]
Next, the operation of the image forming apparatus 1 in the present embodiment will be described.
In the image forming apparatus 1, an image forming process for forming an image on a sheet based on a job is performed.
Further, in the image forming apparatus 1, when the image forming process is performed, a toner collecting process is performed to collect the toner scattered in the image forming unit 30 (the image forming units 30Y, 30M, 30C, and 30K).

  Hereinafter, the toner collection process will be described in detail. FIG. 4 is a flowchart showing the procedure of the toner collection process.

  First, the control unit 50 determines whether or not the job has started (step S1), and when the job has not started (step S1: NO), the process of step S1 is repeated with the standby state.

  When the job is started (step S1: YES), the control unit 50 causes the fan F to start the rotation operation (step S2).

  Next, the control unit 50 detects the wind speed (Vn) by the wind speed detection sensor 129 (step S3).

  Next, the control unit 50 determines whether the amount of toner collected by the collection unit 123 is increased based on whether the detected wind speed (Vn) is lower than the wind speed (Vn-1) stored in advance (step S4). The wind speed (Vn-1) stored in advance is a value measured and stored in the toner collecting process before the current toner collecting process. In the case where the filter unit 26 has just been replaced, preset initial set values are used.

When the detected wind speed (Vn) is higher than the stored wind speed (Vn-1) (step S4: NO), the control unit 50 proceeds to step S10 described later.
On the other hand, when the detected wind speed (Vn) is lower than the stored wind speed (Vn-1) (step S4: YES), the control unit 50 drives the drive unit to block the shielding member 112 and the second shielding member A predetermined amount of 114 is operated (step S5).

  Next, the control unit 50 detects the wind speed (Vn + 1) by the wind speed detection sensor 129 (step S6).

  Next, the control unit 50 calculates the reduction rate of the air volume from the wind speed (Vn) detected in step S3 (step S7).

  Next, the control unit 50 increases the air volume of the fan F by the calculated reduction rate (step S8).

  Next, the control unit 50 detects the wind speed (Vn + 2) by the wind speed detection sensor 129, and stores it in the storage unit 60 (step S9).

Next, the control unit 50 determines whether or not the job is completed (step S10). If the job is not completed (step S10: NO), the control unit 50 returns to the step S3 and repeats the subsequent processing.
On the other hand, when the job ends (step S10: YES), the control unit 50 stops the rotation operation of the fan F (step S11), and ends the present process.

  In the present embodiment, the shielding member 112 and the second shielding member 114 are configured to operate by a predetermined amount. That is, by repeating the process from step S3 to step S10, the opening area can be gradually narrowed.

FIG. 6A is an example showing changes in air volume in the suction duct 111, the cyclone unit 122, and the filter unit 126. FIG. 6 (b) is an example showing changes in wind speed in the suction duct 111, the cyclone unit 122, and the filter unit 126.
6 (a) and 6 (b), the initial state is indicated by a solid line, and when the wind speed is reduced due to the contamination of the filter unit 126, a broken line is indicated. In addition, a state in which the shielding member 112 and the second shielding member 114 are operated is indicated by an alternate long and short dashed line, and a state in which the air volume of the fan F is increased along with the operation of the shielding member 112 and the second shielding member 114 is indicated by a two dotted line. .

As shown in FIG. 6A, according to the arrow (1), the air volume decreases from the initial state (solid line) along with the contamination of the filter portion 126 (dotted line). In this state, when the shielding member 112 and the second shielding member 114 are operated, the opening area is reduced, so the air volume is further reduced according to the arrow (2) (dashed dotted line). Thereafter, by increasing the air volume of the fan F, the air volume is raised to approximately the same level as before operation of the shielding member 112 and the second shielding member 114 according to the arrow (3) (two-dot chain line).
Further, as shown in FIG. 6B, according to the arrow (1), the wind velocity decreases from the initial state (solid line) due to the reduction of the air volume accompanying the contamination of the filter portion 126 (broken line). In this state, when the shielding member 112 and the second shielding member 114 are operated, the air velocity is greatly reduced at the filter portion 126 according to the arrow (2) due to the reduction of the air volume due to the reduction of the opening area. The reduction of the wind speed in the suction duct 111 and the cyclone unit 122 is not as large as that of the filter unit 126. Thereafter, the air flow rate of the fan F is increased to follow the arrow (3) so that the wind speed is approximately the same as before the operation of the shielding member 112 and the second shielding member 114 in the filter portion 126. And the second shielding member 114 is raised more than before operation (two-dot chain line).

As described above, according to the present embodiment, in the image forming apparatus 1 for forming an image on a sheet, the opening area of the duct portion 110 for attracting toner-containing air and the inlet 111a of the duct portion 110 is changed. , A cyclone unit 122 communicating with the duct unit 110 and centrifugally separating the toner from the toner-containing air, a collection unit 123 collecting the toner separated by the cyclone unit 122, and a toner unit separated by the cyclone unit 122 Filter unit 126 for passing the air after being discharged, a fan F for generating a flow of toner-containing air from the duct unit 110 to the filter unit 126, and a fan F with an increase in the amount of toner collected by the collection unit 123. Control unit that narrows the opening area of the duct portion 110 by the shielding member 112 while Including 0 and, the.
Therefore, the air volume reduced by narrowing the opening area of the inflow port 111a of the duct portion 110 is compensated by increasing the air volume of the fan F.
As a result, in the duct portion 110, although the opening area of the inflow port 111a becomes narrow, the air flow rate does not change, so the suction air velocity can be increased.
That is, by simultaneously adjusting the opening area of the inlet 111a of the duct portion 110 and the air volume of the fan F, the suction efficiency can be increased without excessively increasing the air volume of the fan F.
Therefore, it is possible to suppress the decrease in the wind speed and extend the life of the filter unit 126 without causing the toner discharge to the outside of the apparatus.

Further, according to the present embodiment, the photosensitive member 31 and the developing unit 32 for supplying the toner to the photosensitive member 31 are provided, and the inflow port 111 a of the duct unit 110 is disposed in the vicinity of the developing unit 32. A shape 112 guides the toner-containing air in a direction different from the direction toward the developing roller 32 a of the developing unit 32.
Therefore, the suction air velocity can be efficiently increased without suctioning the toner on the developing roller 32a.

Further, according to the present embodiment, the control unit 50 is provided with the second shielding member 114 for changing the opening area of the connection port 113A connecting the duct unit 110 and the cyclone unit 122, and As the amount increases, the opening area of the connection port 113A is narrowed by the second shielding member 114.
For this reason, the air volume reduced by narrowing the opening area of the connection port 113A is compensated by increasing the air volume of the fan F.
As a result, although the opening area of the connection port 113A is narrowed, the air flow rate does not change, so the separation efficiency can be increased.
That is, by simultaneously adjusting the opening area of the connection port 113A and the air volume of the fan F, the separation efficiency can be increased without excessively increasing the air volume of the fan F.

Further, according to the present embodiment, the second shielding member 114 is shaped so as to guide the toner-containing air in the direction along the tangent L1 of the cylinder of the cyclone portion 122.
For this reason, the centrifugal force in the cyclone part 122 can be increased by flowing the wind on the circumference, and the separation efficiency can be further improved.

Further, according to the present embodiment, the second shielding member 114 is shaped to guide the toner-containing air in the direction toward the top of the cyclone portion 122.
For this reason, by suctioning from the upper part of the cyclone part 122, the distance to be centrifuged becomes long, and the separation efficiency can be further improved.

Further, according to the present embodiment, the control unit 50 includes the wind speed detection sensor 129 that detects the wind speed of air after the toner is separated by the cyclone unit 122, and the control unit 50 detects the wind speed detection sensor 129. It is determined that the amount of collected toner has increased.
For this reason, according to the detection result of the wind speed detection sensor 129, the shielding member 112 and the 2nd shielding member 114 can be operated, and the air volume of the fan F can be raised.

[Modification 1]
In the above-described embodiment, a configuration in which the shielding member 112 and the second shielding member 114 are operated and the air volume of the fan F is increased is described based on the detection result of the wind speed detection sensor 129. The configuration may be such that it is determined that the amount of toner collected by the collection unit 123 has increased as the number of sheets of paper has increased.
That is, since the number of sheets on which the image is formed by the image forming unit 30 and the amount of collected toner are in a proportional relationship, the control unit 50 controls the shielding member as the number of sheets on which the image is formed by the image forming unit 30 increases. The 112 and the second shielding member 114 are operated to narrow the opening area of the duct portion 110 and the opening area of the connection port 113A, and increase the air volume of the fan F.
Even with such a configuration, the suction efficiency and the separation efficiency can be raised at an appropriate timing as the amount of toner collected by the collection unit 123 increases.

[Modification 2]
Further, the detection result of the dirt detection sensor 127 may be used to determine that the amount of toner collected by the collection unit 123 has increased, instead of the detection result of the wind speed detection sensor 129.
In this case, when the wind speed detection sensor 129 detects dirt, the control unit 50 operates the shielding member 112 and the second shielding member 114 to a predetermined position, and increases the air volume of the fan F to a predetermined amount.
Even with such a configuration, the suction efficiency and the separation efficiency can be raised at an appropriate timing as the amount of toner collected by the collection unit 123 increases.

  In the above embodiment and the first and second modifications, the configuration in which the shielding member 112 and the second shielding member 114 are simultaneously operated has been described as an example, but only the shielding member 112 may be provided.

  Moreover, as a structure of the shielding member 112 and the 2nd shielding member 114, if the inflow port 111a and the connection port 113A can be shielded, the shape is not limited to the above-mentioned thing. For example, it may be configured to project uniformly from the periphery of the inflow port 111a and the connection port 113A.

Reference Signs List 1 image forming apparatus 10 sheet storage unit 11 tray 12 transport unit 20 image reading unit 21 document table 30 image forming units 30Y, 30M, 30C, 30K image forming unit 31 photosensitive member 32 developing unit 32a developing roller 33 intermediate transfer belt 34 transfer roller 40 fixing unit 50 control unit 60 storage unit 70 operation display unit 100 toner collection mechanism 110 duct unit 111 suction duct 111a inlet 112 shielding member 113 common duct 113A connection port 114 shielding member 120 toner collecting portion 121 inlet 122 cyclone unit 123 Collection unit 124 Reversing unit 125 Air flow passage unit 126 Filter unit 126a Toner dust filter unit 126b Ozone catalyst filter unit 126c Toner dust filter unit 127 Dirt detection sensor 128 Outlet 129 Wind speed detection sensor 120a Handle F fan

Claims (8)

In an image forming apparatus for forming an image on a sheet,
A duct portion for suctioning toner-containing air containing toner;
A shielding member for changing the opening area of the inlet of the duct portion;
A cyclone unit in communication with the duct unit for centrifugally separating the toner from the toner-containing air;
A recovery unit that recovers the toner separated by the cyclone unit;
A filter unit for passing air after the toner is separated by the cyclone unit;
A fan for generating a flow of the toner-containing air from the duct portion to the filter portion;
A control unit configured to increase an air volume of the fan as the amount of toner collected by the collection unit increases and to narrow an opening area of the duct unit by the shielding member;
An image forming apparatus comprising: A photosensitive body; and a developing unit for supplying toner to the photosensitive body,
The inflow port of the duct portion is disposed in the vicinity of the developing portion,
The image forming apparatus according to claim 1, wherein the shielding member is shaped to guide the toner-containing air in a direction different from a direction toward the developing roller of the developing unit. A second shielding member for changing an opening area of a connection port connecting the duct portion and the cyclone portion;
3. The image forming apparatus according to claim 1, wherein the control unit narrows the opening area of the connection port by the second shielding member as the amount of toner collected by the collection unit increases. apparatus.   The image forming apparatus according to claim 3, wherein the second shielding member has a shape for guiding the toner-containing air in a direction along a tangent of a cylinder of the cyclone unit.   The image forming apparatus according to claim 3, wherein the second shielding member is shaped to guide the toner-containing air in a direction toward an upper portion of the cyclone unit. A wind speed detection sensor for detecting a wind speed of air after the toner is separated by the cyclone unit;
The image forming method according to any one of claims 1 to 5, wherein the control unit determines that the amount of toner collected by the collection unit has increased based on the detection result of the wind speed detection sensor. apparatus.   The image forming method according to any one of claims 1 to 5, wherein the control unit determines that the amount of toner collected by the collection unit has increased based on the number of sheets on which an image is formed. apparatus. And a dirt detection sensor for detecting dirt on the filter section,
The image forming method according to any one of claims 1 to 5, wherein the control unit determines that the amount of toner collected by the collection unit has increased based on the detection result of the stain detection sensor. apparatus.

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