JP5504907B2 - Toner aggregation preventing device, image forming apparatus - Google Patents

Description

  The present invention relates to a toner aggregation preventing apparatus and an image forming apparatus including the toner aggregation preventing apparatus.

2. Description of the Related Art In electrophotographic image forming apparatuses such as copying machines, facsimile machines, and printers, an image forming apparatus including a toner replenishing device that replenishes toner stored in a toner container to a developing unit is known (for example, see Patent Document 1). ).
This type of image forming apparatus is usually designed to prevent toner from agglomerating as an in-machine environment during image formation or when the image forming apparatus is turned on, that is, during operation. For this reason, a toner that softens at a lower temperature is often used, and in that case, due to the physical properties of the toner, moisture tends to be absorbed even at a low temperature, and there is a risk of aggregation.
As a solution to such a toner aggregation problem, for example, a device that dehumidifies a photosensitive member and an image forming unit around the photosensitive member (see, for example, Patent Documents 2 and 3), or a toner replenishing device in response to humidity. And a device that controls the operation of a stirring member in the developing unit (see, for example, Patent Document 4).

However, the toner aggregation preventing means described above can be used when image formation is not performed for a long time even when the image forming apparatus is turned on, or when the image forming apparatus is turned off, for example, during long holidays such as summertime. In some cases, such as when the apparatus is turned off, the toner in the apparatus absorbs moisture due to an increase in humidity, and the toner may aggregate.
However, since the carrier and the toner are dispersed in the developer in the developing unit, the toner is only slightly agglomerated, and may be broken by the operation of the image forming apparatus or the agitation described above. It is possible to cope with the aggregation of the toner due to the collapse of the operation of the member or the consumption of the toner in the non-image portion.

  However, in a toner replenishing device or a toner container containing only toner, the toners are in close contact with each other, so that the aggregated toner lump is large, hard, and much. Therefore, the toner aggregate is constantly replenished at the time of image formation, and the toner aggregation preventing means described above cannot return the aggregated toner to its original state, and normal image quality cannot be ensured. End up.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a toner aggregation preventing apparatus capable of solving the above-described problems and an image forming apparatus including the toner aggregation preventing apparatus.

In order to solve the above problems, a toner aggregation preventing apparatus according to the present invention and an image forming apparatus including the toner aggregation preventing apparatus employ the following technical means.
According to a first aspect of the present invention, there is provided a communication portion that connects a developing portion that develops an electrostatic latent image formed on a photoconductor into a toner image and a toner replenishing device that replenishes the toner contained in a toner container to the developing portion. a shutter for opening and closing the said and humidity sensor for detecting the flight of humidity the development unit and the toner supply device image forming apparatus wherein the providing a dehumidifying part for dehumidifying the inside of the toner supply device, in the non-image-forming A control unit that closes the communication unit with the shutter and closes the shutter to close the communication unit and performs dehumidification by the dehumidification unit when the internal humidity detected by the humidity sensor exceeds a predetermined value. And the control unit executes a closing operation of the shutter and a dehumidifying operation by the dehumidifying unit using a command to turn off the main power of the image forming apparatus as a trigger. Toner agglomeration prevention device for performing a switching operation of the main power source characterized.
According to a second aspect of the present invention, there is provided a communication portion that connects a developing portion that develops the electrostatic latent image formed on the photosensitive member into a toner image and a toner replenishing device that replenishes the toner contained in the toner container to the developing portion. A humidity sensor that detects humidity inside the apparatus and a dehumidifying unit that dehumidifies the interior of the toner replenishing device are provided in an image forming apparatus that includes a shutter that opens and closes, the developing unit, and the toner replenishing device. When the detected humidity in the apparatus exceeds a predetermined value and when non-image formation is being performed, the communication portion is closed with the shutter while the toner is stored in a toner container, and the communication portion is closed by closing the shutter. And a control unit that performs dehumidification by the dehumidifying unit later .
According to a third aspect of the present invention, the toner aggregation preventing apparatus according to the second aspect has a toner replenishing device humidity sensor for detecting the humidity inside the toner replenishing device, and after dehumidifying by the dehumidifying unit. When the humidity falls below a predetermined value by the toner replenishing device humidity sensor, the control unit controls the dehumidifying operation by the dehumidifying unit to end .
According to a fourth aspect of the present invention, there is provided an image forming apparatus including the developing unit, the toner replenishing device, and the toner aggregation preventing device according to any one of the first to third aspects.

  According to the present invention, at the time of non-image formation, when the humidity in the image forming apparatus detected by the humidity sensor exceeds a predetermined value, the communication unit connecting the developing unit and the toner replenishing device to which the toner container is connected is blocked by the shutter. Thus, the entry of moisture into the toner replenishing device and the toner container is prevented and the toner is prevented from absorbing moisture, so that toner aggregation in the toner replenishing device including the toner container can be prevented.

1 is a schematic longitudinal sectional front view of an image forming apparatus including a toner aggregation preventing device. FIG. 4 is a schematic longitudinal side view of the toner aggregation preventing device. 3 is a flowchart 1 showing a series of operations of the toner aggregation preventing apparatus. 3 is a flowchart 2 showing a series of operations of the toner aggregation preventing apparatus. FIG. 6 is a schematic longitudinal front view of an image forming apparatus according to another aspect including a toner aggregation preventing device, and a schematic enlarged vertical front view of a main part.

  An embodiment of an image forming apparatus provided with a toner aggregation preventing apparatus according to the present invention will be described with reference to the drawings. Note that the image forming apparatus according to the present embodiment uses a two-component developer composed of toner and a carrier, and only the toner is supplied by a toner container that is detachable from the image forming apparatus.

First, an outline of the image forming apparatus will be described with reference to FIG.
As shown in FIG. 1, the image forming apparatus according to the present embodiment includes an intermediate transfer belt unit, an image forming unit, an image reading unit 10, an exposure unit 11, a paper feed tray unit, and a paper transport unit. The image forming apparatus includes a fixing unit 20 and a toner aggregation preventing device that is a main part of the present invention.

  The intermediate transfer belt portion is provided between and below the driving roller 1, the first driven roller 2 provided to face the driving roller 1, and the first driven roller 2 and the driving roller 1. The second driven roller 3, the endless intermediate transfer belt 4 that can be rotated around these rollers and rotated clockwise, and between the driving roller 1 and the first driven roller 2 and on the back side of the intermediate transfer belt 4 And a primary transfer roller 5 provided at a predetermined interval.

  The image forming unit includes a photosensitive drum 6 (photosensitive member) rotatably provided to face each primary transfer roller 5 with the intermediate transfer belt 4 interposed therebetween, and a primary transfer of each photosensitive drum 6. The cleaning unit 7 for cleaning the surface of the photosensitive drum 6, the charging unit 8 for charging the surface of the photosensitive drum 6, and the electrostatic formed on the surface of the photosensitive drum 6 are provided in order counterclockwise starting from the surface facing the roller 5. And a developing unit 9 for developing the latent image into a toner image. There are four of these components to form toner images of each color of yellow, magenta, cyan, and black (color order varies depending on the system), and these are detachably integrated with the main body of the image forming apparatus. Unit (process unit).

The image reading unit 10 is provided in the upper part of the image forming apparatus main body, and optically reads a document placed on contact glass (not shown) to generate image data.
The exposure unit 11 is provided between the image forming unit and the image reading unit, and emits laser light based on the image data generated by the image reading unit 10 from between the charging unit 9 and the developing unit 9 to the photosensitive drum 6. The electrostatic latent image based on the image data is formed on the surface of the photosensitive drum 6 by irradiating the surface.

  The paper feed tray unit is provided at the lower part of the image forming apparatus main body, and is provided so as to be able to move forward and backward toward the paper stored in the paper feed tray 12 and the paper stored in the paper feed tray 12. And a sheet feeding roller 13 for feeding the sheets one by one. In this embodiment, a two-stage paper feed tray is illustrated.

The paper transport unit includes a first transport path unit 14 and a second transport path unit 15.
The first transport path section 14 includes a plurality of transport rollers and a plurality of guide plates (not shown), and the second driven roller 3 sandwiching the intermediate transfer belt 4 is fed between the paper fed by the paper feed roller 13. It is configured to be able to pass through and to be discharged onto a paper discharge tray 16 provided in the middle of the side surface of the image forming apparatus main body.

  The first transport path 14 is provided so as to face the second driven roller 3 with the intermediate transfer belt 4 interposed therebetween, and a secondary transfer roller 17 that transfers the toner image on the intermediate transfer belt 4 to a sheet. And a registration roller 18 that feeds a sheet at a predetermined timing toward a secondary transfer nip formed by contact between the secondary transfer roller 17 and the intermediate transfer belt 4.

  The second conveyance path unit 15 includes a plurality of conveyance rollers including reverse rollers 19 and a plurality of guide plates (not shown), and branches from the first conveyance path unit 14 immediately before being discharged to the sheet discharge tray 16. At the same time, the sheet having the toner image transferred onto the sheet surface is reversed and joined before the registration roller 18 of the first conveyance path unit 14.

The fixing unit 20 is provided between and in the vicinity of the branch portion between the secondary transfer nip and the first transport path portion 14 of the second transport path portion 15 described above, and an unfixed toner image. Heat and pressure are applied to the paper carrying the toner to melt and solidify the toner image on the paper.
A description of the toner aggregation preventing apparatus, which is the main part of the present invention, will be given later.

In the image forming apparatus configured as described above, in response to an input of an image forming operation start command, the image reading unit 10 optically reads a document placed on a contact glass (not shown) to generate image data. Around this time, the rotating body including the photosensitive drum 6 starts to rotate, and the paper feed roller 13 feeds the paper stored in the lower paper feed tray 12 to the first transport path section 14.
Each charging unit 8 charges the surface of each corresponding photosensitive drum 6 to a uniform potential, and the exposure unit 11 irradiates the surface of each photosensitive drum 6 with a laser beam based on the image data.

  The developing unit 9 supplies toner of a color corresponding to the electrostatic latent image formed on the surface of the photosensitive drum 6 to develop the electrostatic latent image into a specific color. That is, as described above, the photosensitive drum 6 has four colors of yellow, magenta, cyan, and black, and a toner image of each color is developed on each photosensitive drum 6.

  The primary transfer roller 5 primarily transfers the toner image on the photosensitive drum 6 onto the intermediate transfer belt 4 at a contact point with the intermediate transfer belt 4 by the applied transfer bias and pressing force. This primary transfer is executed at a timing so that the four color toner images are superimposed on the intermediate transfer belt 4, and a full color toner image is formed on the intermediate transfer belt 4.

The registration roller 18 stands by with the moved paper interposed therebetween, and sends out the paper in anticipation of the full-color toner image formed on the intermediate transfer belt 4 moving to the secondary transfer nip.
The secondary transfer roller 17 secondarily transfers the full-color toner image on the intermediate transfer belt 4 onto the sheet at the secondary transfer nip by the applied transfer bias and pressing force.
The fixing unit 20 applies heat and pressure to the paper carrying the unfixed full-color toner image to melt the full-color toner image, and solidifies and fixes the full-color toner image on the paper.

  In the case of single-sided printing, the paper is conveyed straight as it is to the paper discharge tray 16, and in the case of double-sided printing, the paper is sent to the second transport path 15 and reversed, and waits until the printing timing on the back side by the registration roller 18. Be made. Thereafter, the toner image is transferred in the same manner as in the case of printing on the front side, passes through the fixing unit 20, and is discharged to the paper discharge tray 16.

  On the other hand, the photosensitive drum 6 after the primary transfer carries the primary transfer residual toner on the surface thereof and is removed by the cleaning unit 7. Thereafter, the surface is uniformly discharged by the quenching lamp 71 to prepare for charging for the next image.

  Further, the intermediate transfer belt 4 that has passed through the secondary transfer nip also carries secondary transfer residual toner on its surface, which is also removed by the intermediate transfer belt cleaning unit 21 to transfer the next toner image. Prepare. By repeating such an operation, single-sided printing or double-sided printing is performed.

  Further, this image forming apparatus writes a solid pattern between a desired image and a desired image with a predetermined exposure amount after performing a predetermined number of image forming cycles of charging, exposure, development and transfer. Is developed in the same manner as a normal image, transferred to the intermediate transfer belt 4, and a solid pattern on the intermediate transfer belt 4 is measured using a measuring unit (not shown) to measure the amount of toner adhesion.

  In general, a reflection type optical sensor is used as the measuring means, and the characteristic that the output of the reflection type optical sensor changes depending on the toner adhesion amount is used. Then, using this measured value (toner adhesion amount per unit area) and the estimated amount of consumed toner calculated from the area of the image forming image, toner supply from the developing unit 9 to the photosensitive drum 6 is performed. The amount is controlled.

Next, with reference to FIG. 2, the details of the periphery of the developing unit 9 and the toner aggregation preventing device that is the main part of the present invention will be described.
The development unit 9 and the toner replenishing device A are provided around the development unit 9.

  The developing unit 9 is a component that develops the electrostatic latent image formed on the surface of the photosensitive drum 6 into a toner image as described above, and detects the ratio of the toner in the two-component developer in the developing unit based on the magnetic permeability. A toner density sensor (not shown), an agitating screw (not shown) for agitating and conveying the two-component developer in the developing unit, and a developing roller 22 for carrying and conveying the developer in a developing area facing the photosensitive drum 6. (See FIG. 1) and a case 23 in which the developing unit 9 is formed and a toner inflow port 9a connected to a toner replenishing device A described later is formed.

  As shown in FIG. 2, the toner replenishing device A includes a toner cartridge 24 as a toner container, a container holder 25, a suction pump 26, a tube 27, and a toner hopper 28.

  The toner cartridge 24 includes an elastic material 241 such as sponge or rubber formed so that a radial (for example, cross-shaped) cut for inserting an insertion rod 254, which will be described later, penetrates both end surfaces, and a substantially cylinder that holds the elastic material 241. Formed into a bag shape with a base 243 configured with a frame-shaped frame 242 and a sheet material such as polyethylene, polyamide resin (nylon), vinyl, or a sheet material such as paper, and the inner peripheral surface of the bag mouth And a toner storage bag 244 that is adhered to the outer peripheral surface of the base 243 and packed with toner.

  Further, as shown in FIG. 2, the toner storage bag 244 is formed in an inclined shape so as to be squeezed toward the base 243 from the midway portion, and through an insertion bar 254 inserted into the bag. It is formed so as to be folded into a predetermined shape each time the toner is sucked. When the toner is completely sucked, the toner storage bag 244 is folded so as not to be bulky and can be easily collected.

  The toner cartridge 24 thus packed with toner can be inserted into a radial (for example, cross-shaped) cut formed in the elastic member 241 of the base 243 simply by being inserted so as to be dropped from the opening 25a of the holder body 251. 254 is inserted, and the toner inflow hole 25c is positioned in the toner storage bag 244 so that the setting is completed.

In order to stably discharge the toner in the toner cartridge 24 to the end, it is preferable that an air layer exists without occupying the entire volume in the toner cartridge 24 with the toner. In this state, the toner is not easily compressed in the toner cartridge 24, and the toner can be discharged smoothly.
In the present embodiment, the toner storage bag 244 is illustrated, but a bottle-like one may be used.

  The container holder 25 includes a holder main body 251 and a joint portion 252.

  The holder main body 251 is formed in a frame shape so as to substantially follow the shape of the toner cartridge 24 so that an opening 25 a for attaching and detaching the toner cartridge 24 is provided at an upper portion and the posture of the toner cartridge 24 is maintained.

  The joint portion 252 is formed in a block shape with an upper portion formed so as to be continuous with the shape of the base 243 and a lower portion extended in the width direction, and at 90 ° so that the upper surface and one side surface communicate with each other. A joint body 253 provided with a bent communication hole 25b, and a base portion is inserted on the upper surface side of the communication hole 25b, and a hollow portion is formed with a sharp tip, and a hollow is formed on the side surface of the front portion. And an insertion rod 254 formed with a toner inflow hole 25c communicating with the portion. The lower portion of the holder main body 251 is inserted into the upper portion of the joint main body 253, and the lower surface of the holder main body 251 and the lower portion of the joint main body 253 are fixed to each other to connect the holder main body 251 and the joint portion 252. Are integrated.

  The suction pump 26 is provided with a suction base 262 on one end side of the casing 261 and an outlet portion 26a on the other end side, and a powder in which a drive shaft 263 connected to the rotor protrudes from the outlet portion 26a side. And a suction pump clutch motor 265 supported by the casing 261 and connected to the drive shaft 263 so as to be able to transmit rotation.

  The suction pump clutch motor 265 and a conveying screw clutch motor 283, which will be described later, are constantly rotating, and rotation is transmitted and cut off by turning the clutch on and off. In this embodiment, the clutch motor is provided as described above. However, a motor without a clutch may be used, and the motor may be rotationally driven as necessary.

  One end of the tube 27 is connected to the side surface of the communication hole 25 b formed in the joint main body 253, and the other end is connected to the suction base 262 of the suction pump 26 to connect the joint portion 252 and the suction pump 26. A flow path is formed.

The toner hopper 28 is opened at a part of the upper surface (left side in FIG. 1) so as to communicate with the outlet part 26a of the suction pump 26, and communicates with the toner inlet 9a provided in the developing part 9. A connection port portion 28a having a part of the lower surface opened and projecting downward is provided, and a machine frame 281 provided so as to connect the developing unit 9 and the suction pump 26, and rotatably spanned in the machine frame 281. A pair of conveying screws 282 for conveying the toner, and a screw shaft projecting out of the machine frame 281 and a conveying screw clutch motor 283 connected so as to be able to transmit rotation are configured. Among the configurations described above, the communication portion B is configured by the toner inflow port 9a and the connection port portion 28a.
Further, a hopper remaining amount sensor for determining whether or not the toner remaining amount in the toner hopper 28 is equal to or larger than a predetermined amount by arranging a piezoelectric sensor surface in the toner hopper 28 at a position in contact with the toner in the toner hopper 28. (Not shown) is provided.

  The toner aggregation preventing apparatus includes a shutter unit 29, a humidity sensor, a dehumidifying unit 31, and a control unit (not shown).

  The shutter unit 29 includes a plate-shaped shutter 291 that is slidably inserted into a groove provided in a lower portion of the connection port portion 28a, and a solenoid 292 that is connected to the base of the shutter 291 and moves the shutter 291 forward and backward. Thus, the shutter 291 opens and closes the communication part B connecting the developing part 9 and the toner replenishing device A. The solenoid 292 is electrically connected to a control unit described later and operates at a predetermined timing. This operation timing will be described later.

  The humidity sensor is provided in the vicinity of the image forming unit, and the humidity sensor 30 (FIG. 1) for detecting the humidity inside the image forming apparatus, and the humidity sensor for hopper that is provided in the toner hopper 28 and detects the humidity inside the toner hopper 28. 33. These humidity sensors are electrically connected to a control unit described later.

The dehumidifying unit includes a cooling type dehumidifier 31 that is electrically connected to a control unit, which will be described later, and that uses a Peltier element, and a pipe 32 that connects the dehumidifier 31 and the outlet 26a. When the humidity detected by the sensor 30 or the hopper humidity sensor 33 exceeds a predetermined value, the air in the toner replenishing device A is sucked through the pipe 32 and the outlet 26a, and dehumidified by the dehumidifier 31. The dehumidified air is sent into the toner replenishing device A through the pipe 32 and the outlet part 26a. The dehumidifier 31 is not limited to the one using the Peltier element described above, and may be configured by other cooling methods such as other cooling methods, compression methods, adsorption methods, absorption methods, and the like.
In this embodiment, a dehumidifier that dehumidifies the inside of the image forming apparatus is provided separately from the dehumidifying unit. This dehumidifier also dehumidifies at a predetermined timing when the humidity detected by the above-described humidity sensor 30 for in-machine humidity exceeds a predetermined value.

  Here, the relationship between the period (weeks) during which the so-called black spot image due to toner aggregation does not occur and the humidity (relative and absolute) under the temperature of 35 ° C. and the temperature of 40 ° C. can be guaranteed. The examination results are shown in Tables 1 and 2.

As shown in Table 1 and Table 2, if the absolute humidity is 15% or less or the relative humidity is in the 30% range, quality abnormalities will not occur even if left in an environment with a temperature of 40 ° C. for 3 consecutive weeks. . As a practical example, it is extremely rare that the temperature is 40 ° C for 3 consecutive weeks when left for a long holiday in summer, so there will be almost no problem in a normal office environment. Become.
In the present embodiment, during non-image formation, the toner replenishing device A has an absolute humidity of less than 15% to prevent toner aggregation.

  When the humidity inside the image forming apparatus detected by the humidity sensor 30 during non-image formation exceeds a predetermined value, the control unit closes the communication unit B with the shutter 291 and performs dehumidification by the dehumidifying unit. The description of the series of control of the toner aggregation preventing apparatus is changed with the description of the operation described later.

  A series of operations of the toner replenishing device A and the toner aggregation preventing device according to the present embodiment configured as described above will be described with reference to FIGS.

First, the toner supply operation by the toner supply device A will be described.
When a toner density sensor (not shown) provided in the developing unit 9 detects that no toner is continuously present for a predetermined time, the suction pump 26 is driven by the clutch of the suction pump clutch motor 265 being connected. At the same time, the clutch of the conveying screw clutch motor 283 is connected and the conveying screw 282 is driven. This driving is intermittent driving.

  When the suction pump 26 starts driving, a suction force is generated in the toner inflow hole 25c through the tube 27, the joint body 253, and the like, and the toner in the toner storage bag 244 is sucked. The sucked toner flows to the toner hopper 28 via the joint portion 252, the tube 27, and the suction pump 26. Next, the toner flows to the toner inlet 9 a by driving the conveying screw 282, and then flows into the developing unit 9 through the toner inlet 9 a. The toner supplied to the developing unit 9 is stirred by a stirring screw in the developing unit 9 and is uniformly charged by being stirred and mixed with a carrier in the developing unit 9.

  Then, when a necessary amount of toner is supplied to the developing unit 9, or when the toner density in the developing unit 9 is normal from the output of a toner density sensor (not shown) provided in the developing unit 9, the control unit of the image forming apparatus When the determination is made, the suction pump clutch motor 265 is disengaged to stop the suction pump 26, and the conveying screw clutch motor 283 is disengaged to stop the conveying screw 282.

  If an upper limit is given in advance to the intermittent driving frequency of the suction pump 26 and the upper limit of the hopper remaining amount sensor detects that there is no toner in the toner hopper 28, the toner storage bag 244 will It is determined that the toner has run out, the drive of the suction pump 26 is stopped, and the user is notified of the replacement of the toner cartridge 24. At this time, the user simply pulls out the toner cartridge 24 in which the toner is emptied, and the radial (for example, cross-shaped) cut formed in the elastic member 241 of the base 243 is closed and detached from the holder main body 251.

Next, a series of operations by the toner aggregation preventing device will be described.
The toner aggregation preventing apparatus according to the present embodiment is shown in FIG. 3 by inputting a power-on command of the main power source of the image forming apparatus or inputting an image forming command when the main power source of the image forming apparatus is already on. The indicated operation is performed.

In response to an input of a power-on command or an image formation command (S1), the shutter 291 moves backward to open the communication part B (S2). The in-machine humidity of the image forming apparatus is detected at an interval of 5 minutes using the in-machine humidity sensor 30 to determine whether the in-machine humidity is 40% or less (S3).
If the in-machine humidity is less than 40% absolute (S3N), in preparation for the next humidity detection, if the in-machine humidity is over 40% absolute (S3Y), it is determined whether or not an image is being formed (during printing operation). (S4). When an image is being formed (S4Y), each component operates and toner aggregation does not occur, so that it is ready for the next humidity detection.

  When the in-machine humidity is 40% or higher and the image is not being formed (S4N), the toner flocculation may occur, so the shutter 291 is advanced to close the communication portion B (S5). As a result, the space formed by the toner cartridge 24, the suction pump 26, the tube 27, and the toner hopper 28 is hermetically sealed by completely blocking the inflow of outside air.

  When the communication portion B is closed, the dehumidifier 31 starts dehumidification in the toner hopper 28 (S6), detects the humidity in the toner hopper 28 using the hopper humidity sensor 33, and determines whether the absolute humidity is 15% or less. (S7). When the humidity in the toner hopper 28 is 15% or higher (S7N), since there is still a possibility that toner agglomerates, dehumidification is continued, and when the humidity in the toner hopper 28 has reached less than 15% absolute humidity ( (S7Y) The dehumidifying operation is terminated because there is no possibility of toner aggregation (S8).

  The opening / closing operation and the dehumidifying operation of the shutter 291 are executed in each toner replenishing device A corresponding to each color of yellow, magenta, cyan, and black.

Further, the toner aggregation preventing apparatus according to the present embodiment performs the operation shown in FIG. 4 in response to the input of the power OFF command of the main power supply of the image forming apparatus.
Based on the input of the power OFF command (S9), it is determined whether or not the above dehumidifying operation is in progress (S10). If dehumidification is in progress (S10Y), dehumidification is continued as it is, and it is determined whether the humidity in the toner hopper 28 is 15% or less of absolute humidity (S14). If the humidity in the toner hopper 28 is 15% or higher (S14N), dehumidification is continued because there is still a possibility of toner aggregation. When the humidity in the toner hopper 28 has reached less than 15% absolute humidity (S14Y), the dehumidifying operation is terminated because there is no possibility of toner aggregation (S15), and the power is turned off (S16).

If the dehumidifying operation is not being performed when the power OFF command is input (S10N), the shutter 291 is advanced to close the communication portion B (S11). When the communication portion B is closed, the humidity in the toner hopper 28 is detected, and it is determined whether the absolute humidity is 15% or more (S12).
When the humidity in the toner hopper 28 is 15% or higher (S12N), dehumidification is started (S13), and operations S14 to S16 are performed as described above. If the humidity in the toner hopper 28 is less than 15% (S12Y), the power is turned off because there is no possibility of toner aggregation (S16).
As described above, the main power off command (power off command) of the image forming apparatus is used as a trigger to perform the closing operation of the shutter 291 and the dehumidifying operation by the dehumidifying unit, and the main power off operation is performed after the execution. To do.

  According to this embodiment, when the absolute humidity in the image forming apparatus detected by the humidity sensor 30 for in-machine humidity is not less than a predetermined value (40%) during non-image formation, the developing unit 9 and the toner hopper 28 are connected. The communication part B is closed by the shutter 291 to prevent the entry of humid air into the toner replenishing device A and the toner cartridge 24. Further, the dehumidifier 31 causes the absolute humidity in the toner replenishing device A to reach a predetermined value ( By dehumidifying the toner until it reaches less than 15%), it is possible to prevent the toner from absorbing moisture. Therefore, it is possible to reliably prevent the toner from aggregating in the toner replenishing device A including the toner cartridge 24.

  Even when a power-off command is input, the shutter 291 is closed and the dehumidifier 31 is dehumidified, and then the main power is turned off. Even if the image forming apparatus is not used for a long time, toner aggregation in the toner replenishing apparatus A provided with the toner cartridge 24 can be reliably prevented.

  In the present embodiment, the toner replenishing device A provided with the toner hopper 28 is illustrated, but the present invention is not limited to this. For example, as shown in FIG. 5, the toner replenishing device without the toner hopper can be applied.

  That is, this type of toner replenishing device has a toner bottle 34 containing only toner and an L-shape when viewed from the front, and a toner discharge port 35b is formed on the bottom of the end of the protruding portion 35a extending in the horizontal direction in the figure. A case 35 provided in the case 35, a holding portion 36 that rotatably holds the toner bottle 34 on the case side wall portion, and a protrusion 35 a that is provided on the protrusion of the case 35 and receives toner from the toner bottle 34. And a connecting pipe 38 connected to the toner discharge port 35 b and the toner inlet 9 a of the developing unit 9. The toner discharge port 35b, the toner inflow port 9a, and the connection pipe 38 constitute a communication portion. An example of an image forming apparatus provided with this type of toner supply device is a laser printer without an optical image reading unit as shown in the figure.

  For the toner replenishing device configured as described above, a plate-like shutter 291 is provided on the upper portion of the connecting pipe 38 so as to be slidable by driving the solenoid 292, and one end of the pipe 32 is provided on the top surface of the end of the protruding portion. And the dehumidifier 31 is connected to the other end of the pipe 32. A case humidity sensor 39 is provided in the case 35 in place of the hopper humidity sensor 33. Thus, the present invention can also be applied to a toner replenishing device without a toner hopper.

  The image forming apparatus provided with the toner aggregation preventing apparatus according to the present embodiment has been described above. However, the above-described embodiment shows an example of a preferred embodiment of the present invention, and the present invention is not limited thereto. The present invention is not limited, and various modifications can be made without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 1 ... Driving roller 2 ... 1st driven roller 3 ... 2nd driven roller 4 ... Intermediate transfer belt 5 ... Primary transfer roller 6 ... Photosensitive drum 7 ... Cleaning part 71 ... Quenching lamp 8 ... Charging part 9 ... Developing part 9a ... Toner Inlet 10 ··· Image reading portion 11 ··· Exposure portion 12 ··· Feed tray 13 ··· Feed roller 14 ··· First transport path portion 15 ··· 2nd transport path portion 16 ··· Discharge tray 17 ··· Secondary transfer roller 18 ··· Registration roller DESCRIPTION OF SYMBOLS 19 ... Reverse roller 20 Fixing part 21 Intermediate transfer belt cleaning part 22 Development roller 23 Case 24 Toner cartridge 241 Elastic material 242 Frame 243 Base 244 Toner storage bag 25 Container holder 25a Opening 25b ... Communication hole 25c ... Toner inflow hole 251 ... Holder body 252 ... Joint part 253 ... Joint example 254 ····························· 26 ··························································································································································· 282 ···························································································································································································· Part 34 ... Toner bottle 35 ... Case 35a ... Projection part 35b ... Toner discharge port 36 ... Holding part 37 ... Conveying screw 38 ... Connection pipe

Japanese Patent Application Laid-Open No. 06-19456 JP 2003-216007 A JP 2004-219691 A Japanese Patent Laid-Open No. 2008-298443

Claims (4)

A shutter for opening and closing the communicating portion which connects the toner replenishing device for replenishing toner stored in the developing unit and the toner container for developing an electrostatic latent image formed on the photosensitive member into a toner image in the developing unit,
A humidity sensor for detecting a flight of humidity in the image forming apparatus provided with said toner replenishing device and the developing unit,
A dehumidifying unit for dehumidifying the inside of the toner replenishing device;
When the humidity inside the apparatus detected by the humidity sensor during non-image formation exceeds a predetermined value, the shutter closes the communicating portion and closes the shutter to close the communicating portion, and then dehumidifies by the dehumidifying portion. A control unit to execute ,
The control unit performs a closing operation of the shutter and a dehumidifying operation by the dehumidifying unit using a command to turn off the main power of the image forming apparatus as a trigger, and executes the main power off operation after the execution. And a toner aggregation preventing apparatus. A shutter that opens and closes a communication unit that connects a developing unit that develops the electrostatic latent image formed on the photosensitive member into a toner image and a toner replenishing device that replenishes the toner contained in the toner container to the developing unit;
A humidity sensor that detects humidity in the apparatus in an image forming apparatus including the developing unit and the toner replenishing device;
A dehumidifying unit for dehumidifying the inside of the toner replenishing device;
When the humidity inside the machine detected by the humidity sensor exceeds a predetermined value and when no image is being formed, the communication portion is closed with the shutter while the toner is stored in a toner container, and the shutter is closed and the communication is performed. And a controller that executes dehumidification by the dehumidifying unit after closing the unit. A toner replenishing device humidity sensor for detecting the humidity inside the toner replenishing device;
The controller controls the end of the dehumidifying operation by the dehumidifying unit when the humidity falls below a predetermined value by the toner replenishing device humidity sensor after dehumidifying by the dehumidifying unit. Item 3. The toner aggregation preventing apparatus according to Item 2.   An image forming apparatus comprising: the developing unit; the toner replenishing device; and the toner aggregation preventing device according to claim 1.

Images