JP2018060050A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve fluidity of a recovered developer delivered to a retention part.SOLUTION: An image forming apparatus comprises: developing bodies; image holding bodies that each hold an image formed through development with a liquid developer supplied from the developing body and transfer the image to a transfer target body; retention parts that each retain the liquid developer and supply the liquid developer to the developing body while a toner density of the liquid developer is adjusted; first recovery parts that each recover the liquid developer from the developing body after the supply of the liquid developer to the image holding body and deliver a first recovered developer to the retention part; and second recovery parts that each recover the liquid developer from the image holding body after the transfer of the image to the transfer target body, and when an image density of the image is lower than a predetermined reference value, add a second recovered developer to the first recovered developer to be delivered to the retention part.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image forming apparatus.

  Patent Document 1 discloses a wet image forming apparatus. In this wet image forming apparatus, the cleaning blade removes the liquid developer remaining on the developing roller after being supplied with the cleaning liquid, and the removed liquid developer is recovered in the recovery tank to be reused. Is done. The liquid developer collected in the collection tank is discharged to the developing tank after the toner concentration is adjusted in the density adjusting unit.

JP 2009-300904 A

  In a configuration in which an image is formed by supplying a liquid developer from a developer to a photoreceptor, in the case where the liquid developer is recovered from the developer after the liquid developer is supplied and the liquid developer is sent to a storage unit, Depending on the image density of the image formed by the body, the fluidity of the liquid developer sent to the storage portion changes. That is, when the image density is low, the amount of toner in the liquid developer supplied from the developer to the image carrier is small, so the collected developer collected from the developer has a large amount of toner particles relative to the carrier liquid. Thus, the fluidity is reduced.

  The present invention improves the fluidity of the collected developer sent to the storage unit, compared to a configuration in which only the collected developer collected from the developer is always sent to the storage unit, regardless of the image density of the formed image. For the purpose.

  According to a first aspect of the present invention, there is provided a developing member, an image holding member that holds an image formed by development with a liquid developer supplied from the developing member, and the image is transferred to a transfer member, and the liquid developing member. A storage unit for storing the developer and supplying the liquid developer to the developer in a state where the toner concentration of the liquid developer is adjusted; and after supplying the liquid developer to the image carrier, A first recovery unit that recovers the liquid developer from the developer and sends the first recovered developer to the storage unit; and the liquid developer from the image carrier after the transfer of the image to the transfer target. A second collection unit that collects and adds the second collected developer to the first collected developer sent to the storage unit when the image density of the image is lower than a predetermined reference value; Prepare.

  According to a second aspect of the present invention, the second collection unit contains the second collected developer, and has a containing unit through which the second collected developer is sent toward the storage unit, and the image density of the image Is greater than or equal to the reference value, the second collected developer is sent to the container.

  According to a third aspect of the present invention, the second collection unit includes a second collection developer discharge unit that discharges the second collection developer, and the image density of the image is equal to or higher than the reference value. When the storage capacity of the storage section reaches the upper limit, the second recovered developer is discharged to the second recovered developer discharge section.

  According to a fourth aspect of the present invention, the first collection unit includes a first collection developer discharge unit that discharges the first collection developer, and an image density of the image is a first reference value as the reference value. The first collected developer is discharged to the first collected developer discharge section when the value is higher than a predetermined second reference value that is higher.

  According to the configuration of the first aspect of the present invention, regardless of the image density of the image to be formed, compared with the configuration in which only the first recovered developer recovered from the developer is always sent to the storage unit, The fluidity of the first recovered developer can be improved.

  According to the configuration of claim 2 of the present invention, the toner concentration of the first recovered developer is compared with the configuration in which the second recovered developer is always added to the first recovered developer regardless of the image density of the formed image. Can be suppressed from being excessively reduced, and the second recovered developer can be reused.

  According to the configuration of the third aspect of the present invention, it is possible to suppress the overflow of the storage portion as compared with the configuration in which the second recovered developer is always sent to the storage portion regardless of the storage amount of the storage portion.

  According to the configuration of the fourth aspect of the present invention, the toner concentration of the liquid developer in the storage portion is excessive as compared with the configuration in which the first recovered developer is always sent to the storage portion regardless of the image density of the formed image. Can be suppressed.

1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment. FIG. 2 is a schematic diagram illustrating a configuration of an image forming unit of a toner image forming unit according to the exemplary embodiment. FIG. 3 is a schematic diagram illustrating a configuration of a supply mechanism and a recovery mechanism of a toner image forming unit according to the present embodiment. It is a flowchart which shows the operation | movement flow of the collection | recovery operation | movement which concerns on this embodiment.

  Below, an example of an embodiment concerning the present invention is described based on a drawing.

(Image forming apparatus 10)
First, the configuration of the image forming apparatus 10 according to the present embodiment will be described. FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus 10 according to the present embodiment.

  As shown in FIG. 1, the image forming apparatus 10 includes an image forming unit 14 that forms a toner image (an example of an image) on a continuous paper P (an example of a recording medium) conveyed in the direction of arrow A, and a toner image. And a fixing device 16 that fixes the continuous paper P. The recording medium is not limited to paper such as continuous paper P, and may be, for example, a film.

(Fixing device 16)
The fixing device 16 includes a heating roll 62 that heats the continuous paper P and a pressure roll 64 that pressurizes the continuous paper P. In the fixing device 16, the continuous paper P is sandwiched between the heating roll 62 and the pressure roll 64, and the continuous paper P is pressurized while being heated, so that the toner image on the continuous paper P is fixed to the continuous paper P.

(Image forming unit 14)
The image forming unit 14 includes toner image forming units 14Y, 14M, 14C, and 14K (hereinafter referred to as 14Y to 14K) that form toner images of yellow (Y), magenta (M), cyan (C), and black (K). Have). The toner image forming units 14Y, 14M, 14C, and 14K are arranged in this order from the upstream side in the transport direction of the continuous paper P.

  Each of the toner image forming units 14 </ b> Y to 14 </ b> K includes an image forming unit 18, a transfer unit 20, a supply mechanism 100 (see FIG. 3), and a collection mechanism 60. Since the toner image forming units 14Y to 14K are basically configured in the same manner except for the toner to be used, the reference numerals of the respective toner image forming units 14M, 14C, and 14K are omitted in FIG. .

(Image forming unit 18)
The image forming units 18 of the toner image forming units 14Y to 14K are units that form toner images using the liquid developer G. Specifically, as shown in FIG. 2, the image forming unit 18 rotates an image holding body 22 that holds a toner image, a charging device 24 that charges the image holding body 22, and an image holding body 22. An exposure device 26 that irradiates exposure light to form an electrostatic latent image, and a developing device 40 that develops the electrostatic latent image on the image carrier 22 to form a toner image are included.

  The developing device 40 includes a developing roll 42 (an example of a developing member), a supply roll 44, a developer tank 46, and a charging device 48. The developer tank 46 is composed of a container having an open top, and stores the liquid developer G therein.

  The supply roll 44 is a roll that holds the liquid developer G and supplies the liquid developer G to the development roll 42. Specifically, a part of the outer peripheral surface of the supply roll 44 is immersed in the liquid developer G in the developer tank 46, and the other part of the outer peripheral surface is in contact with the outer peripheral surface of the developing roll 42. The supply roll 44 rotates following the development roll 42.

  The developing roll 42 is a roll that develops the electrostatic latent image formed on the image carrier 22 with the liquid developer G. Specifically, a part of the outer peripheral surface of the developing roll 42 is in contact with the outer peripheral surface of the supply roll 44, and the other part of the outer peripheral surface is in contact with the outer peripheral surface of the image carrier 22. The developing roll 42 rotates following the image carrier 22.

  In the developing device 40, the supply roll 44 holds the liquid developer G in the developer tank 46 on the outer peripheral surface, conveys the liquid developer G to the contact position with the developing roll 42 by rotation, The liquid developer G is supplied to the developing roll 42 at the contact position.

  The liquid developer G supplied to the developing roll 42 is supplied from the developing roll 42 to the image carrier 22 after the toner is charged to the liquid developer G by the charging device 48. The liquid developer G develops the electrostatic latent image on the image carrier 22 to form a toner image. Note that when the electrostatic latent image is developed as a toner image using the liquid developer G, the carrier liquid also moves to the image holding member 22.

  The liquid developer G used in the present embodiment is a liquid type liquid developer in which toner (particles) is dispersed in a carrier liquid. As the carrier liquid, for example, an insulating liquid such as vegetable oil, liquid paraffin oil, or silicone oil is used. In addition, as an example, the liquid developer G in the developer tank 46 has toner (particles) dispersed in a carrier liquid at a concentration of 20% by mass.

(Transfer unit 20)
The transfer unit 20 is a unit that transfers the toner image formed by the image forming unit 18 to the continuous paper P. Specifically, the transfer unit 20 includes a transfer roll 50 (an example of a transfer target) and a backup roll 52.

  The transfer roll 50 is disposed opposite to the image carrier 22 and rotates, and a toner image on the image carrier 22 is transferred by an electric field formed between the transfer roller 50 and the image carrier 22. The backup roll 52 is disposed on the opposite side of the transfer roll 50 with the continuous paper P interposed therebetween, and transfers the toner image on the transfer roll 50 to the continuous paper P by an electric field formed between the backup roll 50.

  When the toner image is transferred from the image carrier 22 to the transfer roll 50, not only the toner but also the carrier liquid moves to the transfer roll 50.

(Supply mechanism 100)
As shown in FIG. 3, the supply mechanism 100 includes a storage device 102 (an example of a storage unit) that stores the liquid developer G, and a density adjustment mechanism 120 that adjusts the concentration of the liquid developer G. Yes. The storage device 102 includes a storage container 110, a stirring member 112, and a dispersion device 150.

(Storage container 110, stirring member 112)
The storage container 110 has a function of storing the liquid developer G. Specifically, the storage container 110 is configured by a container having an open top.

  The stirring member 112 is provided inside the storage container 110. The agitating member 112 agitates the liquid developer G by rotating around an axis along the vertical direction, and reduces toner density unevenness.

  One end of the developer supply path 114 is connected to the lower portion of the storage container 110, and the other end of the developer supply path 114 is connected to the developer tank 46. A pump 116 is provided in the developer supply path 114. By driving the pump 116, the liquid developer G whose concentration is adjusted as described later by the concentration adjusting mechanism 120 is supplied from the storage container 110 to the developer tank 46.

(Distributor 150)
The dispersing device 150 applies a shearing force to the toner aggregate contained in the liquid developer G containing the collected developers GA and GB collected by the collecting mechanism 60 to decompose and redisperse the liquid developer G in the carrier liquid. It is a device to let you. Specifically, the dispersing device 150 includes a funnel member 152, a net member 154 provided inside the funnel member 152, and a plate member 156 that rotates about an axis along the vertical direction.

  A recovery path 76, a developer supply path 129, and a carrier liquid supply path 134, which will be described later, are connected to the upper part of the funnel member 152. The liquid developer G including the recovered developers GA and GB recovered by the recovery mechanism 60 Inflow. The liquid developer G is rubbed against the mesh member 154 by the rotating plate member 156 and passes through the mesh member 154. As a result, a shearing force is applied to the toner aggregate of the liquid developer G, and the toner aggregate is decomposed and redispersed in the carrier liquid. The liquid developer G in which the toner is redispersed is stored in the storage container 110.

(Density adjustment mechanism 120)
The density adjustment mechanism 120 includes a detection path 122 that sends the liquid developer G in the storage container 110 to the dispersion device 150, and a detection unit 124 (for example, an ultrasonic density sensor) that is provided in the detection path 122 and detects toner concentration. A carrier liquid tank 132 for storing the carrier liquid, and a developer tank 128 for storing a high-concentration developer whose toner concentration is higher than a predetermined reference toner concentration.

  The carrier liquid tank 132 is connected to the funnel member 152 of the dispersion device 150 by a carrier liquid supply path 134. A pump 136 is provided in the carrier liquid supply path 134. By driving the pump 136, the carrier liquid in the carrier liquid tank 132 is supplied to the storage container 110 through the carrier liquid supply path 134 and the funnel member 152.

  The developer tank 128 is connected to the funnel member 152 of the dispersion device 150 by a developer supply path 129. A pump 127 is provided in the developer supply path 129. By driving the pump 127, the developer in the developer tank 128 is supplied to the storage container 110 through the developer supply path 129 and the funnel member 152.

  Then, in the density adjustment mechanism 120, based on the toner density detected by the detection unit 124, the toner density of the liquid developer G stored in the storage container 110 is a predetermined reference toner density (for example, a density of 20% by mass). The control unit 19 (see FIG. 1) adjusts the density by supplying the carrier liquid in the carrier liquid tank 132 and the high-concentration developer in the developer tank 128 to the storage container 110.

(Recovery mechanism 60)
The recovery mechanism 60 includes a first recovery device 70 (an example of a first recovery unit), a second recovery device 80 (an example of a second recovery unit), and a third recovery device 63.

(First recovery device 70)
The first recovery device 70 removes the liquid developer G remaining on the developing roll 42 after supplying the liquid developer G to the image holding body 22, that is, after developing the electrostatic latent image on the image holding body 22. It is a device to collect from. Specifically, the first recovery device 70 includes a scraping blade 72, a container 74, a recovery path 76, a pump 78, and a waste liquid tank 79 (an example of a first recovery developer discharge unit). ing.

  The scraping blade 72 is a member that scrapes off the liquid developer G remaining on the developing roll 42 from the developing roll 42. The scraping blade 72 is configured by, for example, a plate-like rubber blade having a length along the axial direction (the depth direction of the paper surface) of the developing roll 42. The tip of the scraping blade 72 is downstream of the contact position with the image carrier 22 in the rotation direction of the development roll 42 and upstream of the contact position with the supply roll 44. In contact with.

  The container 74 receives the collected developer GA (an example of a first collected developer) scraped by the scraping blade 72 and functions as a storage unit that temporarily stores the collected developer GA. The container 74 is configured by a container having an upper opening, and the collected developer GA scraped by the scraping blade 72 flows from the upper opening. As will be described later, the collected developer GB collected by the second collection device 80 is sent to the container 74 through the collection path 86.

  Inside the container 74, a stirring member 73 for stirring the recovered developer GA is provided. Specifically, the agitating member 73 rotates around the axis along the longitudinal direction of the scraping blade 72, thereby agitating the collected developer GB and the collected developer GA collected by the second collecting device 80. Thus, unevenness in toner density is reduced.

  The collection path 76 functions as a flow path for sending the collected developer GA stored in the container 74 to the dispersion device 150. Specifically, one end of the recovery path 76 is connected to the bottom of the container 74, and the other end is connected to the top of the funnel member 152 of the dispersing device 150. The pump 78 is provided in the recovery path 76.

  A switching valve 77 is provided downstream of the pump 78 in the collection path 76 in the flow direction. The waste liquid tank 79 has a function of discharging the collected developer GA and storing the collected developer GA, and is connected to a switching valve 77 via a discharge path 75.

  That is, in the first recovery device 70, the switching valve 77 can be switched between a route for sending the recovered developer GA to the funnel member 152 of the dispersing device 150 and a discharge route for discharging the recovered developer GA to the waste liquid tank 79. It has become.

(Second recovery device 80)
The second recovery device 80 is a device that recovers the liquid developer G remaining on the image carrier 22 from the image carrier 22 after the transfer of the toner image to the transfer roll 50. Specifically, the second recovery device 80 includes a scraping blade 82, a container 84, a recovery path 86, a pump 88, a waste liquid tank 89 (an example of a second recovered developer discharge unit), and a sub tank 92 ( An example of a housing portion).

  The scraping blade 82 is a member that scrapes the liquid developer G remaining on the image carrier 22 from the image carrier 22. The scraping blade 82 is configured by, for example, a plate-like rubber blade having a length along the axial direction (the depth direction of the paper surface) of the image carrier 22. The tip of the scraping blade 82 is on the downstream side with respect to the contact position with the transfer roll 50 in the rotation direction of the image carrier 22 and on the upstream side with respect to the contact position with the developing roll 42. 22 is in contact.

  The container 84 receives the collected developer GB (an example of the second collected developer) scraped by the scraping blade 82 and functions as a storage unit that temporarily stores the collected developer GB. The container 84 is configured by a container having an upper opening, and the collected developer GB scraped by the scraping blade 82 flows from the upper opening.

  The collection path 86 functions as a flow path for sending the collected developer GB stored in the container 84 to the container 74 of the first collection device 70. Specifically, one end of the recovery path 86 is connected to the bottom of the container 84. Further, the other end of the recovery path 86 is disposed in the container 74 of the first recovery apparatus 70, and the recovered developer GB that flows out from the other end of the recovery path 86 flows into the container 84. The pump 88 is provided in the collection path 86.

  A switching valve 87 is provided downstream of the pump 88 in the collection path 86 in the flow direction. The waste liquid tank 89 has a function of discharging the collected developer GB and storing the collected developer GB, and is connected to a switching valve 87 via a discharge path 85.

  Further, the sub tank 92 has a function of accommodating the collected developer GB, and is connected to the switching valve 87 via the flow passage 94. The sub-tank 92 is provided with a sensor (not shown) as a detection unit that detects whether or not the capacity has reached the upper limit. As an example, the sensor detects the liquid level of the sub tank 92, and detects that the storage amount has reached the upper limit by detecting that the liquid level has exceeded a predetermined height.

  That is, in the second recovery device 80, the switching valve 87 causes a route for sending the recovered developer GB to the container 74 of the first recovery device 70, a route for sending the recovered developer GB to the sub tank 92, and the recovered developer GB as waste liquid. Switching to a discharge path for discharging to the tank 79 is possible.

  The sub tank 92 is connected to the carrier liquid tank 132 via the flow passage 96. A pump 97 is provided in the flow passage 96. By driving the pump 97, the recovered developer GB is sent from the sub tank 92 to the carrier liquid tank 132.

(Third recovery device 63)
The third collection device 63 is a device that collects the liquid developer G remaining on the transfer roll 50 from the transfer roll 50 after the transfer of the toner image onto the continuous paper P. Specifically, the third recovery device 63 scrapes the liquid developer G remaining on the transfer roll 50 from the transfer roll 50, and a container that receives the recovered developer GC scraped off by the scraping blade 61. 65. The collected developer GC received by the container 65 is discharged to the waste liquid tank 89 through the discharge path 67. That is, the collected developer GC is discarded without being reused.

(Control unit 19)
The control unit 19 is configured to acquire job data and an image formation command from an external device (not shown). Upon receiving the job data, the control unit 19 controls each unit of the image forming apparatus 10 such as a transport unit (not shown) that transports the continuous paper P, the image forming unit 14, and the fixing device 16, and executes an image forming operation. The job data includes image data that causes the toner image forming units 14Y to 14K to form toner images. Also, the image data includes image density (%) data for forming a toner image.

  The image density is a pixel of a toner image developed by the developing device 40 with respect to the total number of pixels included per unit area when the exposure device 26 forms one exposure dot formed on the image carrier 22. A percentage of a number.

  A job refers to a processing unit of an image forming operation that is processed (executed) by the control unit 19 in response to an image forming command.

  Further, the control unit 19 controls each part of the image forming apparatus 10 such as the supply mechanism 100 and the recovery mechanism 60 to execute a recovery operation in the recovery mechanism 60. For example, the collection operation is executed for each job after the image forming operation is completed. Below, the specific procedure of collection | recovery operation | movement is demonstrated.

(Recovery operation)
In this embodiment, as shown in FIG. 4, first, whether or not the image density of the toner image formed on the image carrier 22 is lower than a predetermined first reference value (for example, 30%). (Step 102 (“S” in the figure stands for “Step”)).

  If the image density is lower than the first reference value, the recovered developer GB recovered from the image holding member 22 in step 104 is sent to the container 74 of the first recovery device 70. As a result, the recovered developer GB is added to the recovered developer GA in the container 74 of the first recovery device 70. Then, the process proceeds to step 116.

  When the image density is equal to or higher than the first reference value, the process proceeds to step 106, and it is determined whether or not the capacity of the sub tank 92 is lower than the upper limit. If the stored amount is lower than the upper limit, the collected developer GB is sent to the sub tank 92 in step 108. Then, the process proceeds to step 112.

  If the storage amount has reached the upper limit, the collected developer GB is discharged to the waste liquid tank 89 at step 110. Then, the process proceeds to step 112.

  As described above, when the image density is equal to or higher than the first reference value, the recovered developer GB is not sent to the container 74 of the first recovery device 70.

  In step 112, it is determined whether or not the image density of the toner image formed on the image carrier 22 is higher than a predetermined second reference value (for example, 80%) higher than the first reference value. .

  If the image density is higher than the second reference value, the collected developer GA is discharged to the waste liquid tank 79 in step 114, and the collecting operation is completed.

  If the image density is less than or equal to the second reference value, in step 116, the collected developer GA is sent to the storage container 110 via the funnel member 152 of the dispersing device 150, and the collecting operation is completed.

(Operation according to this embodiment)
Next, the operation according to this embodiment will be described.

  In the present embodiment, as described above, when the image density of the toner image formed on the image carrier 22 is lower than a predetermined first reference value, the collected developer GB from the image carrier 22 is removed. It sends to the container 74 of the 1st collection | recovery apparatus 70 (refer S102, S104). As a result, the recovered developer GB from the image carrier 22 is added to the recovered developer GA from the developing roll 42 in the container 74 of the first recovery device 70.

  Here, when the image density of the toner image is low, the amount of toner of the liquid developer G supplied from the developing roll 42 to the image holding body 22 is small, and thus the collected developer GA recovered from the developing roll 42 is The amount of toner particles with respect to the carrier liquid increases and the fluidity decreases.

  On the other hand, the collected developer GB collected from the image carrier 22 is collected after the toner image is transferred to the transfer roll 50, and therefore contains almost no toner. That is, the recovered developer GB is a liquid equivalent to the carrier liquid and has higher fluidity than the liquid developer G containing toner particles.

  Then, the recovered developer GB equivalent to the carrier liquid is added to the recovered developer GA recovered from the developing roll 42, and the recovered developer GA to which the recovered developer GB is added passes through the recovery path 76 to the dispersion device 150. It is sent to the funnel member 152.

  For this reason, the collected developer GA sent to the funnel member 152 is always compared with the configuration in which only the collected developer GA collected from the developing roll 42 is always sent to the funnel member 152 of the dispersing device 150 regardless of the image density of the toner image. Improve fluidity. Thereby, it is suppressed that the collected developer GA is clogged in the collection path 76.

  Further, in the present embodiment, when the image density of the toner image is equal to or higher than the first reference value and the storage amount of the sub tank 92 is lower than the upper limit, the collected developer GB from the image carrier 22 is removed. It is sent to the sub tank 92 (see S102, S106, S108). Further, the collected developer GB sent to the sub tank 92 is sent to the carrier liquid tank 132 and then supplied to the storage container 110 through the dispersion device 150.

  For this reason, the toner concentration of the recovered developer GA is suppressed from being excessively reduced as compared with the configuration in which the recovered developer GB is always added to the recovered developer GA regardless of the image density of the toner image. GB is reused as a carrier liquid.

  Furthermore, in this embodiment, when the image density of the toner image is equal to or higher than the first reference value and the storage capacity of the sub-tank 92 has reached the upper limit, the collected developer from the image holding member 22 is used. The GB is discharged to the waste liquid tank 89 (see S102, S106, S110).

  Therefore, the overflow of the subtank 92 is suppressed compared to the configuration in which the collected developer GB is always sent to the subtank 92 regardless of the capacity of the subtank 92.

  In this embodiment, when the image density of the toner image is higher than the second reference value higher than the first reference value, the collected developer GA from the developing roll 42 is discharged to the waste liquid tank 79 (S112, (See S114).

  For this reason, regardless of the image density of the toner image, the toner concentration of the liquid developer G in the storage container 110 is suppressed from being excessively reduced as compared with the configuration in which the collected developer GA is always sent to the funnel member 152. This facilitates toner density adjustment in the storage container 110.

(Modification)
In the present embodiment, the transfer roll 50 is used as an example of the transfer target, but the present invention is not limited to this. As an example of the transfer target, for example, a transfer belt or a recording medium may be used.

  Moreover, in this embodiment, although the subtank 92 was used as an example of an accommodating part, it is not restricted to this. As an example of the storage unit, the carrier liquid tank 132 may be used. That is, the collected developer GB may be sent directly from the container 84 to the carrier liquid tank 132.

  The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made without departing from the spirit of the present invention. For example, the modification examples described above may be appropriately combined.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 22 Image holding body 42 Developing roll (an example of developing body)
50 Transfer roll (an example of a transfer target)
70 First collection device (an example of a first collection unit)
79 Waste liquid tank (example of first recovery developer discharge part)
80 Second collection device (an example of a second collection unit)
89 Waste liquid tank (an example of the second recovered developer discharge unit)
92 Subtank (an example of a storage part)
102 storage device (an example of a storage unit)
G Liquid developer GA Collected developer (example of first collected developer)
GB recovered developer (example of second recovered developer)

Claims (4)

A developer,
An image holding body that holds an image formed by development with a liquid developer supplied from the developing body, and the image is transferred to a transfer target;
A storage unit for storing the liquid developer and supplying the liquid developer toward the developer in a state where the toner concentration of the liquid developer is adjusted;
A first recovery unit that recovers the liquid developer from the developer after the liquid developer is supplied to the image carrier, and sends the first recovered developer to the storage unit;
When the liquid developer is recovered from the image carrier after the transfer of the image to the transfer target, and the image density of the image is lower than a predetermined reference value, the second recovered developer, A second recovery unit to be added to the first recovery developer sent to the storage unit;
An image forming apparatus comprising: The second collection unit is
Storing the second recovered developer, and having a storage portion to which the second recovered developer is sent toward the storage portion;
The image forming apparatus according to claim 1, wherein when the image density of the image is equal to or higher than the reference value, the second collected developer is sent to the storage unit. The second collection unit is
A second recovered developer discharge portion for discharging the second recovered developer;
When the image density of the image is equal to or higher than the reference value and the storage capacity of the storage section reaches the upper limit, the second recovered developer is discharged to the second recovered developer discharge section. The image forming apparatus according to claim 2. The first recovery part has a first recovery developer discharge part for discharging the first recovery developer,
When the image density of the image is higher than a predetermined second reference value that is higher than the first reference value as the reference value, the first recovered developer is discharged to the first recovered developer discharge portion. The image forming apparatus according to claim 1.