JP2013033095A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that forms an image with higher quality on a recording medium.SOLUTION: An image forming apparatus includes: an intermediate transfer body 53; a transfer unit U2; and an application mechanism 20 that is arranged to face the intermediate transfer body 53, and applies pre-wet liquid to a toner image T held by the intermediate transfer body 53 on the upstream of the transfer unit U2 in a direction of movement of the toner image T. The application mechanism 20 includes a coating body 24 to which the pre-set liquid 22 is supplied. The coating body 24 is arranged so that the pre-wet liquid 22 can be in contact with the surface of the intermediate transfer body 53. The surfaces of the intermediate transfer body 53 and the coating body 24 move at substantially the same speed to each other. The pre-wet liquid 22 is applied to the toner image T through the contact with the toner image T. When the pre-wet liquid 22 is applied to the toner image T, the toner image is pressed against the intermediate transfer body 53 by a potential difference formed between the intermediate transfer body 53 and the coating body 24.

Description

  The present invention relates to an image forming apparatus using a developer in which toner particles are dispersed in a carrier liquid.

  JP 2000-019849 A (Patent Document 1), JP 04-001687 A (Patent Document 2), JP 07-271107 A (Patent Document 3), and JP 08-152788 A (Patent Document 2). As disclosed in Document 4), an image forming apparatus (also referred to as a wet image forming apparatus) using a developer (also referred to as a liquid developer) is known.

  A developer used in such an image forming apparatus includes a carrier liquid and toner particles dispersed in the carrier liquid. On the other hand, in an image forming apparatus (dry image forming apparatus) employing a dry electrophotographic system, toner particles are used as they are.

  An image forming apparatus using a developing solution can use toner particles having a smaller particle diameter as compared with a dry image forming apparatus. Finer portions of the image are represented by toner particles having a smaller particle size. According to the image forming apparatus using the developer, a high-quality image can be formed on the recording medium.

JP 2000-019849 A Japanese Patent Laid-Open No. 04-001687 JP 07-271107 A Japanese Patent Laid-Open No. 08-152788

  In the image forming apparatuses disclosed in Patent Documents 1 to 4, it is attempted to form a high-quality image on a recording medium by using a prewetting liquid.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that uses a developing solution and that can form a higher quality image on a recording medium.

  An image forming apparatus according to the present invention is an image forming apparatus that forms an image on a recording medium using a developer in which toner particles are dispersed in a carrier liquid, and is a developer that forms a toner image from the developer. Formed between an apparatus, an image carrier that moves the toner image while holding the toner image, and a surface of the image carrier and a surface of a transfer member that moves along the surface of the image carrier. The toner image held on the image carrier is disposed so as to face the surface of the image carrier and a first transfer portion where the toner image is transferred to the transfer member, and the toner is located more than the first transfer portion. A first application mechanism that applies a first prewetting liquid to the toner image held on the image carrier on the upstream side of the image movement direction, and the first application mechanism has a first application mechanism on a surface thereof. First application to which pre-wet liquid is supplied And a first potential difference forming device that forms a first potential difference between the surface of the image carrier and the surface of the first application body, wherein the first application body is a surface of the first application body. The first pre-wet liquid supplied to the image carrier is disposed so as to come into contact with the surface of the image carrier, and the image carrier and the first application body are formed on the surface of the image carrier and the first application body. The first pre-wet liquid is driven so that the surfaces thereof move at substantially the same speed, and the first pre-wet liquid is brought into contact with the toner image held on the image carrier by the mutual contact. The toner held on the image carrier when the first pre-wet liquid is applied to the toner image applied to the toner image held on the image carrier and held on the image carrier. The image is formed on the surface of the image carrier by the first potential difference. It is pressed against.

  Preferably, the first application mechanism adjusts the amount of the first pre-wet liquid, and the toner held on the image carrier upstream of the first transfer unit in the moving direction of the toner image. The first prewetting liquid is applied to the image.

  Preferably, the first application mechanism adjusts the amount of the first pre-wet liquid according to the type of the recording medium. Preferably, the first pre-wet liquid is the same material as the carrier liquid. Preferably, the image carrier is a photoconductor disposed so as to face the developing device.

  Preferably, the member to be transferred is an intermediate transfer member disposed so as to face the photoconductor, and the surface of the intermediate transfer member and the surface of the recording medium moving along the surface of the intermediate transfer member The toner image held between the intermediate transfer member and the second transfer portion is transferred to the recording medium. The second transfer portion is disposed so as to face the surface of the intermediate transfer member. A second application mechanism that applies a second pre-wet liquid to the toner image held on the intermediate transfer member on the upstream side of the moving direction of the toner image, and the second application mechanism comprises: A second application body to which the second pre-wet liquid is supplied to the surface, and a second potential difference forming device that forms a second potential difference between the surface of the intermediate transfer body and the surface of the second application body. The second application body includes the second application body. The second pre-wet liquid supplied to the surface of the intermediate transfer member is disposed so as to come into contact with the surface of the intermediate transfer member, and the intermediate transfer member and the second application member include the surface of the intermediate transfer member and the second application member. The second pre-wet liquid is driven so that the surface of the body moves at substantially the same speed, and the second pre-wet liquid is brought into contact with the toner image held on the intermediate transfer body by mutual contact. When the second pre-wet liquid is applied to the toner image that is applied to the toner image held on the intermediate transfer member and is held on the intermediate transfer member, the toner image is held on the intermediate transfer member. The toner image is pressed against the surface of the intermediate transfer member by the second potential difference.

  Preferably, the image carrier is an intermediate transfer member, and a photosensitive member disposed to face both the developing device and the intermediate transfer member, a surface of the photosensitive member, and a surface of the intermediate transfer member. A second transfer portion formed between the second transfer portion and the toner image held on the photosensitive member is transferred to the intermediate transfer member; and the second transfer portion is disposed so as to face the surface of the intermediate transfer member. A third application mechanism that applies a third pre-wet liquid to the surface of the intermediate transfer member on the upstream side of the surface of the intermediate transfer member in the moving direction.

  According to the present invention, it is possible to obtain an image forming apparatus that uses a developing solution and can form a higher quality image on a recording medium.

1 is a schematic diagram illustrating a general image forming apparatus using a developer. FIG. 2 is a schematic diagram illustrating an enlarged vicinity of a transfer unit in the image forming apparatus in FIG. 1. FIG. 3 is a plan view showing a recording medium on which a toner image is uniformly transferred. FIG. 3 is a plan view showing a recording medium on which a toner image is transferred non-uniformly. It is a schematic diagram showing an improvement example of a general image forming apparatus using a developer. It is a schematic diagram which shows the other general image forming apparatus using a developing solution. FIG. 7 is an enlarged schematic diagram illustrating the vicinity of a transfer portion in the image forming apparatus in FIG. 6. It is a schematic diagram which shows the example of improvement of the other general image forming apparatus using a developing solution. 1 is a schematic diagram illustrating an image forming apparatus according to Embodiment 1. FIG. 3 is a schematic diagram illustrating an image forming unit used in the image forming apparatus according to Embodiment 1. FIG. 6 is a schematic diagram illustrating an image forming unit used in the image forming apparatus according to Embodiment 2. FIG. 6 is a schematic diagram illustrating an image forming unit used in an image forming apparatus according to Embodiment 3. FIG. 6 is a schematic diagram illustrating an image forming unit used in an image forming apparatus according to Embodiment 4. FIG. FIG. 10 is a schematic diagram illustrating an image forming unit used in an image forming apparatus according to a fifth embodiment. FIG. 10 is a schematic diagram partially showing an image forming unit used in an image forming apparatus in a sixth embodiment. FIG. 10 is a schematic diagram partially showing an image forming unit used in an image forming apparatus according to a seventh embodiment. FIG. 10 is a schematic diagram partially showing an image forming unit used in an image forming apparatus according to an eighth embodiment.

[Reference technology]
Before describing each embodiment based on this invention, the general reference technique regarding this invention is demonstrated. In the description of the reference technology, the same parts and corresponding parts are denoted by the same reference numerals, and the repeated description may not be repeated.

  In an image forming apparatus using a developer, a so-called wet electrophotographic development method is used. As described at the beginning, the developer is formed by dispersing toner particles in a liquid (carrier liquid). The wet electrophotographic development method includes a direct transfer method and an intermediate transfer method.

(Direct transfer method)
In the direct transfer method, the electrostatic latent image carried on the surface of the photoreceptor is developed with a developer. The electrostatic latent image is developed on the surface of the photoconductor, whereby the electrostatic latent image forms a toner image. The toner image formed on the surface of the photoreceptor is transferred to a recording medium such as recording paper. The toner image transferred to the recording medium is fixed on the surface of the recording medium by heating and pressing. In the direct transfer method, an output from the image forming apparatus can be obtained as described above.

(Intermediate transfer method)
In the intermediate transfer method, an intermediate transfer member is used. The toner image formed on the surface of the photoreceptor is once transferred to the intermediate transfer body before being transferred to the recording medium. The toner image is transferred from the intermediate transfer member to a recording medium such as a recording sheet. The toner image transferred to the recording medium is fixed on the surface of the recording medium by heating and pressing. In the intermediate transfer method, an output from the image forming apparatus can be obtained as described above.

  In both the direct transfer method and the intermediate transfer method, when the toner image is transferred, the toner particles in the developer are charged. When the toner particles are charged, the toner particles are transferred by an electric force.

  When the toner image is transferred from the photosensitive member to the intermediate transfer member, a power supply device is provided on both or one of the photosensitive member and the intermediate transfer member. By forming a potential difference (transfer electric field) between the photosensitive member and the intermediate transfer member, the toner particles move.

  When a toner image is transferred from an image carrier (photosensitive member or intermediate transfer member) to a recording medium such as recording paper, a transfer member is provided so as to face the image carrier with the recording medium such as recording paper interposed therebetween. . A power supply device is provided on both or one of the image carrier and the transfer member. By forming a potential difference (transfer electric field) between the image carrier and the transfer member, the toner particles move.

  Here, in order to form a higher quality image on the recording medium, it is necessary to transfer the toner image satisfactorily so that the toner image is not disturbed during the transfer process. In an image forming apparatus that employs a wet electrophotographic system (including a direct transfer system and an intermediate transfer system), since a developer is used, the toner image is likely to be disturbed during the transfer process. The reason will be described below.

(Image forming apparatus 100)
FIG. 1 is a schematic diagram showing a general image forming apparatus 100 using a developer. In the image forming apparatus 100, the transfer member 1 that rotates in the direction of the arrow A1 and the image carrier 2 that rotates in the direction of the arrow A2 are disposed so as to face each other. The image carrier 2 in the image forming apparatus 100 is a photosensitive member or an intermediate transfer member. The image carrier 2 carries a toner image T (T1). A transfer electric field (not shown) is formed between the transfer member 1 and the image carrier 2. A transfer portion Q including a nip portion is formed between the transfer member 1 and the image carrier 2.

  The recording medium P such as recording paper is transported along the transport direction AR so as to pass through the transfer portion Q. The toner image T (T1) is transferred from the image carrier 2 (photosensitive member or intermediate transfer member) to the recording medium P by the action of a transfer electric field in the transfer portion Q. A toner image T (T2) is formed on the surface of the recording medium P.

  FIG. 2 is an enlarged schematic view showing the vicinity of the transfer portion Q in the image forming apparatus 100 in FIG. As described above, a transfer electric field is formed between the transfer member 1 and the image carrier 2 in order to move (transfer) the toner image T (T1) carried on the image carrier 2 toward the recording medium P. Is done.

  An electric force is applied to the toner particles forming the toner image T (T1) by the transfer electric field. This electric force acts in a direction to move (transfer) the toner particles from the image carrier 2 to the recording medium P. As the toner particles move onto the recording medium P, a predetermined image is formed on the recording medium P.

  Here, the transfer electric field formed between the transfer member 1 and the image carrier 2 is not only the nip portion N (the portion where the toner image T and the recording medium P are in close contact) but also the upstream side of the nip portion N. It also acts on region E. That is, the transfer electric field formed between the transfer member 1 and the image carrier 2 acts not only on the nip portion N but also on the region R having a predetermined width.

  On the upstream side (region E) of the nip portion N, unlike the nip portion N, the toner particles forming the toner image T (T1) are not constrained by the surface of the image carrier 2. When the toner particles enter the region E upstream of the nip portion N, the toner particles start to move in the carrier liquid C by the action of the transfer electric field in the region E.

  If there is a gap between the surface of the carrier liquid C located on the surface of the image carrier 2 and the surface of the recording medium P, the toner particles are correctly positioned at predetermined positions even if the image carrier 2 rotates. It becomes difficult to move and also moves in the direction of the surface of the image carrier 2.

  The toner particles are likely to gather locally, and the toner particles do not move to a portion that should originally move as the image carrier 2 rotates. As a result, the toner image T (T1) is transferred to the recording medium P with the toner particles locally gathered.

  FIG. 3 is a plan view showing the recording medium P on which the toner image is uniformly transferred. FIG. 4 is a plan view showing the recording medium P on which the toner image is transferred non-uniformly. 3 and 4, when the toner image is transferred to the recording medium P in a state where the toner particles are locally gathered, as shown in FIG. 4, the white background portion increases and the image density decreases. Image distortion occurs. When image disturbance occurs, it becomes difficult to form a high-quality image on the recording medium P.

  Referring to FIG. 5, in order to suppress the occurrence of such image disturbance, when the toner image T (T1) is transferred to the recording medium P, a liquid (carrier liquid) is previously provided upstream of the nip portion N. A measure to keep the amount of C) larger than usual is conceivable. The amount H2 of the carrier liquid C shown in FIG. 5 is larger than the amount H1 of the carrier liquid C shown in FIG.

  A large amount of liquid (carrier liquid C) held on the surface of the image carrier 2 does not completely enter the nip portion N, but accumulates upstream of the nip portion N. In the vicinity of the nip portion N on the upstream side of the nip portion N, a liquid pool D is formed by the liquid (carrier liquid C).

  By forming the liquid pool D so as to include the region E (the region where the toner particles are affected by the transfer electric field on the upstream side of the nip portion N), it is possible to prevent the toner particles from locally gathering and moving. . The toner particles can move to a predetermined position to be moved with the rotation of the image carrier 2. As a result, the occurrence of image disturbance as described above can be suppressed, and a recording medium P (recording medium P on which a toner image is uniformly transferred) as shown in FIG. 3 can be obtained.

(Image forming apparatus 101)
In FIG. 1 and FIG. 2, the image disturbance that occurs when the toner image is transferred from the image carrier 2 (photoconductor or intermediate transfer member) to the recording medium P has been described. This image disturbance can also occur when the toner image is transferred from the image carrier 2 (photosensitive member) to the intermediate transfer member.

  FIG. 6 is a schematic diagram showing another general image forming apparatus 101 using a developing solution. In the image forming apparatus 101, the intermediate transfer member 3 that rotates in the direction of arrow A3 and the image carrier 2 that rotates in the direction of arrow A2 are disposed so as to face each other. In the image forming apparatus 101, the image carrier 2 is a photoconductor.

  A transfer electric field (not shown) is formed between the intermediate transfer member 3 and the image carrier 2. A transfer portion S including a nip portion is formed between the intermediate transfer member 3 and the image carrier 2. The toner image T (T1) carried by the image carrier 2 is transferred from the image carrier 2 to the intermediate transfer member 3 by the action of the transfer electric field in the transfer portion S. A toner image T (T2) is formed on the surface of the intermediate transfer body 3.

  FIG. 7 is an enlarged schematic diagram showing the vicinity of the transfer portion S in the image forming apparatus 101 in FIG. As described above, a transfer electric field is generated between the intermediate transfer body 3 and the image carrier 2 in order to move (transfer) the toner image T (T1) carried on the image carrier 2 toward the intermediate transfer body 3. It is formed.

  An electric force is applied to the toner particles forming the toner image T (T1) by the transfer electric field. This electric force acts in a direction to move (transfer) the toner particles from the image carrier 2 to the intermediate transfer member 3. As the toner particles move onto the intermediate transfer body 3, a toner image T (T2) is formed on the intermediate transfer body 3.

  As in the case of the above-described image forming apparatus 100 (see FIG. 1), the transfer electric field formed between the intermediate transfer member 3 and the image carrier 2 is a nip portion N (toner image T and intermediate transfer member 3). Not only the portion where the nip portion N is in close contact) but also the region E upstream of the nip portion N. A transfer electric field formed between the intermediate transfer member 3 and the image carrier 2 acts not only on the nip portion N but also on a region R having a predetermined width.

  On the upstream side (region E) of the nip portion N, unlike the nip portion N, the toner particles forming the toner image T (T1) are not constrained by the surface of the image carrier 2. When the toner particles enter the region E upstream of the nip portion N, the toner particles start to move in the carrier liquid C by the action of the transfer electric field in the region E.

  When there is a gap between the surface of the carrier liquid C located on the surface of the image carrier 2 and the surface of the intermediate transfer member 3, the toner particles are in a predetermined position even if the image carrier 2 rotates. It becomes difficult to move correctly and also moves in the direction of the surface of the image carrier 2.

  The toner particles are likely to gather locally, and the toner particles do not move to a portion that should originally move as the image carrier 2 rotates. As a result, the toner image T (T1) is transferred to the intermediate transfer member 3 in a state where the toner particles are locally collected. When an image is finally formed on the recording medium, image disturbance such as a decrease in image density occurs on the recording medium. It is difficult to form a high-quality image on a recording medium.

  Referring to FIG. 8, the following measures can be considered to suppress the occurrence of such image disturbance. As in the case described above with reference to FIG. 5, when the toner image T (T1) is transferred to the intermediate transfer body 3, the amount of the liquid (carrier liquid C) is set in advance on the upstream side of the nip portion N in advance. There are also many states. The amount H4 of the carrier liquid C shown in FIG. 8 is larger than the amount H3 of the carrier liquid C shown in FIG.

  A large amount of liquid (carrier liquid C) held on the surface of the image carrier 2 does not completely enter the nip portion N, but accumulates upstream of the nip portion N. In the vicinity of the nip portion N on the upstream side of the nip portion N, a liquid pool D is formed by the liquid (carrier liquid C).

  By forming the liquid pool D so as to include the region E (the region where the toner particles are affected by the transfer electric field on the upstream side of the nip portion N), it is possible to prevent the toner particles from locally gathering and moving. . The toner particles can move to a predetermined position to be moved with the rotation of the image carrier 2. As a result, the occurrence of image disturbance as described above can be suppressed, and a recording medium P (recording medium P on which a toner image is uniformly transferred) as shown in FIG. 3 can be obtained.

  As a means for retaining a large amount of liquid (pre-wet liquid) upstream of the nip portion N as in the embodiment shown in FIG. 5 and the embodiment shown in FIG. 8, for example, Japanese Patent Laid-Open No. 2000-019849 (Patent Document 1) shows. The structure which can be considered is considered. In this configuration, the carrier liquid is applied (pre-wet) to the recording paper before the toner image is transferred to the recording paper.

  However, when the carrier liquid is applied to the recording paper, the carrier liquid is absorbed by the recording paper before transfer. As the carrier liquid to be pre-wet, in addition to the amount necessary for forming the liquid pool as described above in the vicinity of the nip portion upstream of the nip portion, the amount of the liquid absorbed by the recording paper is required. . Therefore, it is not efficient to apply (pre-wet) the carrier liquid to the recording paper before the toner image is transferred to the recording paper.

  On the other hand, in the configuration of Japanese Patent Laid-Open No. 04-001687 (Patent Document 2), the carrier liquid is not applied (pre-wet) to the recording paper. In this configuration, the carrier liquid flows from the slit toward the image carrier (photosensitive member or intermediate transfer member). The carrier liquid is applied to the image carrier before the toner image is transferred onto the recording paper in a state where a liquid pool is formed by the blade.

  However, when the carrier liquid is applied using a blade, the toner image formed on the image carrier may be disturbed by the blade. When the toner image is disturbed, it becomes difficult to form a high-quality image on the recording medium.

[Embodiment]
Embodiments based on the present invention will be described below with reference to the drawings. In the description of each embodiment, when referring to the number, amount, or the like, the scope of the present invention is not necessarily limited to the number, amount, or the like unless otherwise specified. In the description of each embodiment, the same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated. Unless there is a restriction | limiting in particular, it is planned from the beginning to use suitably combining the structure shown in each embodiment.

[Embodiment 1]
(Image forming apparatus 102)
With reference to FIG. 9, the image forming apparatus 102 in the present embodiment will be described. The image forming apparatus 102 forms an image on the recording medium P that is transported along the transport direction AR. The image forming apparatus 102 includes four image forming units 60 (60A to 60D), five paper transport rollers 7 (7A to 7E), a paper feeding device 17, a fixing device 18, and a paper discharge device 19.

  Although details will be described later, each of the four image forming units 60 (60A to 60D) includes a transfer unit U1 (primary transfer unit) and a transfer unit U2 (secondary transfer unit). Each of the five paper transport rollers 7 (7A to 7E) rotates in the direction of arrow A7. The four image forming units 60 (60A to 60D) and the five paper transport rollers 7 (7A to 7E) are alternately arranged along the transport direction AR of the recording medium P.

  In FIG. 9, the recording medium P is shown to have a length that allows the recording medium P to reach the paper discharge device 19 from the paper supply device 17. It may be longer or shorter than this length.

  A plurality of recording media P are stored in the paper feeding device 17. The recording medium P is sent from the paper feeding device 17 to the paper transport roller 7 (7A) by a paper feeding mechanism (not shown) provided in the paper feeding device 17. While the recording medium P is transported by the paper transport rollers 7 (7A to 7E), an image is formed on the surface (recording surface) of the recording medium P by the image forming unit 60 (60A to 60D).

  In FIG. 9, four image forming units 60 (60A to 60D) are illustrated, but the number of image forming units 60 is increased or decreased according to the number of developers used. The image forming unit 60 (60A to 60D) in the present embodiment corresponds to each color of Y (Yellow: yellow), M (Magenta: magenta), C (Cyan: cyan), and K (blacK: black). doing.

  The arrangement order of yellow, magenta, cyan, and black can be changed as appropriate. As the image forming unit 60 (60A to 60D), colors other than yellow, magenta, cyan, and black may be used.

  Hereinafter, the configuration and function of the image forming unit 60 (60A to 60D) will be described. The configuration and function of the image forming unit 60 (60A to 60D) are common to each other. Hereinafter, each of the image forming units 60 (60A to 60D) will be described as the image forming unit 60 with reference to FIG. The image forming unit 60 shown in FIG. 10 has a configuration common to the image forming units 60 (60A to 60D) regardless of the color of the developer to be used.

(Image forming unit 60)
As shown in FIG. 10, the image forming unit 60 includes a transfer member 51, an intermediate transfer member 53, a photosensitive member 52, a coating mechanism 10, a coating mechanism 20, a latent image writing unit 52 </ b> K, and a developing device 40.

  The transfer member 51 is disposed between the adjacent paper transport rollers 7. Two sheet transport rollers 7 face one transfer member 51. The transfer member 51 rotates in the direction of arrow A51. The paper transport roller 7 rotates in the direction of arrow A7. The recording medium P is transported along the transport direction AR so as to pass between the transfer member 51 and the paper transport roller 7.

  The intermediate transfer member 53 is disposed so as to face the transfer member 51. The intermediate transfer member 53 rotates in the direction of arrow A53. A transfer unit U2 (secondary transfer unit) is formed between the surface of the intermediate transfer member 53 and the surface of the recording medium P that moves along the surface of the intermediate transfer member 53.

  The photosensitive member 52 is disposed so as to face the intermediate transfer member 53. The photoconductor 52 rotates in the direction of arrow A52. A transfer portion U1 (primary transfer portion) is formed between the surface of the photosensitive member 52 and the surface of the intermediate transfer member 53 that moves along the surface of the photosensitive member 52.

  The latent image writing unit 52K is arranged to face the surface of the photoconductor 52. The latent image writing unit 52K writes an electrostatic latent image (not shown) on the surface of the photoreceptor 52. The latent image writing unit 52K can erase the electrostatic latent image from the photosensitive member 52 after the primary transfer, or can write the electrostatic latent image again by charging and exposing the surface of the photosensitive member 52.

  The photoconductor 52 holds the electrostatic latent image formed by the latent image writing unit 52K. The electrostatic latent image moves in the direction of arrow A52 in accordance with the movement of the surface of the photoconductor 52 as the photoconductor 52 rotates. Although the details will be described later, the electrostatic latent image is developed as a toner image T (T52) by the developing device 40. The photoreceptor 52 can also carry a toner image T (T52). The toner image T (T52) also moves in the direction of the arrow A52 in accordance with the movement of the surface of the photoconductor 52 as the photoconductor 52 rotates.

(Developing device 40)
The developing device 40 includes a developing tank 41, a developer 42, a supply roller 43, a leveling roller 44, and a developer carrier 45. The developing device 40 forms a toner image T (T52) from the developer 42.

  Specifically, the developer 42 is stored in the developing tank 41. The developer 42 includes toner particles and a carrier liquid. The toner particles are dispersed in the carrier liquid at a predetermined ratio. Supply roller 43 rotates in the direction of arrow A43. The developer 42 is pumped up by the supply roller 43.

  The leveling roller 44 rotates in the direction of arrow A44. The developer 42 pumped up by the supply roller 43 is sent to the leveling roller 44. The surplus developer 42 pumped up on the surface of the supply roller 43 is scraped off by the regulating blade 43T before being sent to the leveling roller 44. In the leveling roller 44, the developer 42 is adjusted so that the film thickness of the developer 42 is uniform.

  The developer carrier 45 rotates in the direction of arrow A45. The developer 42 whose film thickness has been adjusted is transferred to the developer carrier 45. The toner particles in the developer 42 transferred to the developer carrier 45 are charged by the development charger 45M.

  The photoreceptor 52 is disposed so as to face the developer carrier 45. As described above, the photoconductor 52 rotates in the direction of the arrow A52. An electrostatic latent image (not shown) is formed on the surface of the photoreceptor 52 by the latent image writing unit 52K. The toner particles in the developer 42 carried by the developer carrier 45 are electrostatically moved from the surface of the developer carrier 45 to the surface of the photoreceptor 52 by the electric field formed by the voltage application device 45V.

  The electrostatic latent image formed on the surface of the photoreceptor 52 is developed as a toner image T (T52) by the developer 42. The shape of the toner image T (T52) corresponds to the shape of the electrostatic latent image formed on the surface of the photoconductor 52. The photosensitive member 52 moves the toner image T (T52) in the direction of arrow A52 while carrying the toner image T (T52). The developer 42 that has not transferred from the developer carrying member 45 to the photosensitive member 52 is scraped off by the cleaning blade 45T and then collected.

  The coating mechanism 10 is disposed so as to face the surface of the photoreceptor 52. The prewetting liquid 12 is supplied to the toner image T (T52) developed on the surface of the photoreceptor 52 by the coating mechanism 10. Details of the configuration and function of the coating mechanism 10 will be described later.

  Thereafter, the toner image T (T52) is primarily transferred from the photosensitive member 52 to the intermediate transfer member 53 in the transfer portion U1 (primary transfer portion) by an electric field formed by the voltage applying device 53V. The toner image T (T52) is carried by the intermediate transfer member 53 as the toner image T (T53). Toner remaining on the surface of the photoconductor 52 without being primarily transferred, dirt on the surface of the photoconductor 52, and the like are scraped off from the surface of the photoconductor 52 by the cleaning blade 52T.

  The coating mechanism 20 is disposed so as to face the surface of the intermediate transfer member 53. The prewetting liquid 22 is supplied to the toner image T (T53) carried on the surface of the intermediate transfer member 53 by the coating mechanism 20. Details of the configuration and function of the coating mechanism 20 will be described later.

  Thereafter, the toner image T (T53) is secondarily transferred to the recording medium P in the transfer portion U2 (secondary transfer portion) by the electric field formed by the voltage application device 51V. Toner remaining on the surface of the intermediate transfer member 53 without being secondarily transferred and dirt on the surface of the intermediate transfer member 53 are scraped off from the surface of the intermediate transfer member 53 by the cleaning blade 53T.

  The recording medium P is secondarily transferred at the transfer unit U2 in each of the image forming units 60 (60A to 60D) (see FIG. 1), and then sent to the fixing device 18 (see FIG. 1). The toner particles in the respective color toner images transferred to the recording medium P are heated and pressurized by the fixing device 18. The toner images of the respective colors transferred to the recording medium P are fixed on the surface of the recording medium P by this heating and pressurization. Thereafter, the recording medium P is discharged from the paper discharge device 19 (see FIG. 1). As described above, the printing operation in the image forming apparatus 102 is completed.

(Details of configuration and function of coating mechanism 10)
Next, the configuration and function details of the coating mechanism 10 will be described. As described above, the coating mechanism 10 is disposed so as to face the surface of the photoreceptor 52. The application mechanism 10 applies the pre-wet liquid 12 to the toner image T (T52) carried on the photoconductor 52 on the upstream side of the transfer unit U1 in the moving direction of the toner image T (T52).

  Specifically, the application mechanism 10 includes a supply tank 11, a pre-wet liquid 12, a scooping roller 13, an application body 14, and a potential difference forming device 14V. The prewetting liquid 12 for application to the photoreceptor 52 is stored in the supply tank 11.

  The pre-wet liquid 12 is a liquid that can disperse toner particles in the liquid. In the pre-wet liquid 12, the toner image T (T52) is transferred from the photosensitive member 52 to the intermediate transfer member by moving toner particles in the transfer portion U1 in the portion where the transfer electric field is formed. It is a liquid that can be transferred to 53.

  As the pre-wet liquid 12, for example, a liquid having the same material as the carrier liquid contained in the developer 42 can be used. The prewetting liquid 12 is replenished to the supply tank 11 from a supply device (not shown) as necessary.

  The scooping roller 13 rotates in the direction of arrow A13. The pumping roller 13 pumps the pre-wet liquid 12 from the supply tank 11. As the drawing roller 13, for example, a roller having an uneven shape on the surface, such as an anilox roller, can be used.

  The application body 14 rotates in the direction of arrow A14. The prewetting liquid 12 pumped up by the pumping roller 13 is supplied to the surface of the application body 14. As the application body 14, a roller that can hold an appropriate amount of the pre-wet liquid 12 on the surface thereof is used. A cleaning blade 13T that contacts the surface of the pumping roller 13 may be provided at a position downstream of the nip portion formed between the pumping roller 13 and the application body 14.

  The application body 14 is disposed so as to contact or substantially contact both the drawing roller 13 and the photosensitive member 52. The application body 14 is arranged so that the pre-wet liquid 12 supplied to the surface of the application body 14 is in contact with the surface of the photoreceptor 52. The applying body 14 uniformly holds the pre-wet liquid 12 supplied from the scooping roller 13 on the surface, and then applies it to the photoconductor 52. The pre-wet liquid 12 is applied to the toner image T (T52) held on the photoconductor 52 by mutual contact between the pre-wet liquid 12 and the toner image T (T52) held on the photoconductor 52. It will be.

  The surface of the coated body 14 and the surface of the photosensitive body 52 are approximately the same speed so that the coated body 14 and the photosensitive body 52 do not disturb the toner image T (T52) carried on the photosensitive body 52. Driven (driven) to move.

  As an arrangement method of the application body 14 with respect to the photoconductor 52, a method of pressing the surface of the application body 14 against the surface of the photoconductor 52 by pressing the rotation shaft of the application body 14 with a spring or the like can be mentioned. In addition to this method, as an arrangement method of the coated body 14 with respect to the photosensitive member 52, a ring-shaped pushing amount regulating member having a diameter smaller than the diameter of the coated body 14 is provided at both ends of the coated body 14, and the pushing amount is set. A method of fixing the application body 14 in a state where the regulating member is pushed in is also mentioned.

  In addition to these methods, as a method of arranging the coated body 14 with respect to the photosensitive member 52, a ring-shaped interval regulating member having a diameter larger than the diameter of the coated body 14 is provided at both ends of the coated body 14, and the coated body. There is also a method of fixing the application body 14 in a state in which an appropriate gap is maintained between the photosensitive member 14 and the photoconductor 52.

  The scooping roller 13 may be provided with a control mechanism that controls the rotation speed of the scooping roller 13. The control mechanism adjusts the rotation speed of the pumping roller 13 so that the amount of the pre-wet liquid 12 on the surface of the application body 14 is adjusted to an appropriate value. As long as the amount of the pre-wet liquid 12 on the surface of the application body 14 is in an appropriate range, the rotation direction of the scooping roller 13 may be opposite to the arrow A13 direction.

  The appropriate amount of the pre-wet liquid 12 on the surface of the coated body 14 means that the pre-wet liquid 12 applied to the toner image T (T52) carried on the surface of the photosensitive body 52 is the photosensitive body 52. This is the amount of the pre-wet liquid 12 that can form a liquid pool of an amount necessary and sufficient to prevent image disturbance due to the transfer electric field in the upstream portion of the nip portion between the intermediate transfer body 53 and the intermediate transfer body 53.

  The potential difference forming device 14 </ b> V is connected to the application body 14. The potential difference forming device 14 </ b> V generates a potential difference between the surface of the application body 14 and the surface of the photoreceptor 52. The value of the potential difference is such that the toner particles are not disturbed by the contact (or substantially contact) of the toner image T (T52) carried on the surface of the photoreceptor 52 with the application body 14. The electric field is adjusted so as to remain on the surface of 52.

  For example, assume that the toner particles are positively charged in the developing device 40. When the photoconductor 52 is grounded, the surface of the application body 14 is adjusted to have a positive potential. The value of the potential is appropriately adjusted according to the charge amount of the toner particles. When the pre-wet liquid 12 is applied to the toner image T (T52) held on the photoconductor 52, the toner image T (T52) held on the photoconductor 52 is changed to the photoconductor by the potential difference formed by the potential difference forming device 14V. It will be pressed against the surface of 52. Due to this potential difference, the toner image T (T52) is suppressed from moving to the application body 14 side.

(Operation and effect by the coating mechanism 10)
As described above, before the toner image T (T52) is transferred from the photosensitive member 52 to the intermediate transfer member 53, the toner image T (T52) carried on the surface of the photosensitive member 52 is applied to the coating mechanism 10 by the coating mechanism 10. A pre-wet liquid 12 is applied. The toner image T (T52) carried on the surface of the photoreceptor 52 is in a state where a large amount of the pre-wet liquid 12 (carrier liquid) is held.

  When the toner image T (T52) passes through the transfer portion U1, a large amount of the pre-wet liquid 12 (carrier liquid) that has been retained does not enter the nip portion but accumulates upstream of the nip portion. In the vicinity of the nip portion on the upstream side of the nip portion, a liquid pool is formed by the pre-wet liquid 12 (carrier liquid) (see the liquid pool D in FIG. 8).

  By forming a liquid pool so that the toner particles include a region affected by the transfer electric field on the upstream side of the nip portion, the local movement of the toner particles is suppressed. The toner particles can move to a predetermined position where the toner particles should move as the photoconductor 52 rotates. As a result, the occurrence of image disturbance can be suppressed, and a recording medium P on which a higher quality image as shown in FIG. 3 is formed (a recording medium P on which a toner image is uniformly transferred) can be obtained. It becomes.

  Further, in image forming apparatus 100 (see FIG. 9) in the present embodiment, a potential difference is formed between application body 14 and photosensitive body 52 by potential difference forming apparatus 14V. The pre-wet liquid 12 is applied to the toner image T (T52) held on the photoconductor 52 by mutual contact between the pre-wet liquid 12 and the toner image T (T52) held on the photoconductor 52. . When the prewetting liquid 12 is applied to the toner image T (T52) held on the photoconductor 52, the toner image T (T52) held on the photoconductor 52 is caused by the above-described potential difference formed by the potential difference forming device 14V. And pressed against the surface of the photosensitive member 52.

  Due to the above-described potential difference, the toner image T (T52) is suppressed from moving toward the application body 14, and the pre-wet liquid 12 and the toner image T (T52) held on the photoconductor 52 are brought into contact with each other. The prewetting liquid 12 is effectively transferred (moved) from the coated body 14 side to the photosensitive body 52 side. When the pre-wet liquid 12 is transferred (when the pre-wet liquid 12 is applied to the toner image T (T52)), the toner image T (T52) carried on the surface of the photoreceptor 52 is in contact with the application body 14. Will not be disturbed. As a result, the occurrence of image disturbance can be suppressed, and a recording medium P on which a higher quality image as shown in FIG. 3 is formed (a recording medium P on which a toner image is uniformly transferred) can be obtained. It becomes.

(Details of configuration and function of coating mechanism 20)
Next, the details of the configuration and function of the coating mechanism 20 will be described. As described above, the coating mechanism 20 is disposed so as to face the surface of the intermediate transfer member 53. The application mechanism 20 applies the pre-wet liquid 22 to the toner image T (T53) carried on the intermediate transfer body 53 on the upstream side of the transfer unit U2 in the moving direction of the toner image T (T53). The coating mechanism 20 is configured similarly to the coating mechanism 10.

  Specifically, the application mechanism 20 includes a supply tank 21, a pre-wet liquid 22, a scooping roller 23, an application body 24, and a potential difference forming device 24V. The pre-wet liquid 22 to be applied to the intermediate transfer member 53 is stored in the supply tank 21.

  The pre-wet liquid 22 is a liquid that can disperse toner particles in the liquid. In the pre-wet liquid 22, the toner image T (T53) is transferred from the intermediate transfer body 53 to the recording medium by moving the toner particles in the liquid in the transfer portion U2 where the transfer electric field is formed. A liquid that can be transferred to P.

  As the pre-wet liquid 22, for example, a liquid having the same material as the carrier liquid contained in the developer 42 can be used. The prewetting liquid 22 is replenished to the supply tank 21 from a supply device (not shown) as necessary.

  The scooping roller 23 rotates in the direction of arrow A23. The pumping roller 23 pumps up the pre-wet liquid 22 from the supply tank 21. As the drawing-up roller 23, a roller having an uneven shape on the surface, such as an anilox roller, can be used.

  The application body 24 rotates in the direction of arrow A24. The prewetting liquid 22 pumped up by the pumping roller 23 is supplied to the surface of the application body 24. As the application body 24, a roller capable of holding an appropriate amount of the pre-wet liquid 22 on its surface is used. A cleaning blade 23T that abuts on the surface of the pumping roller 23 may be provided at a position downstream of the nip portion formed between the pumping roller 23 and the application body 24.

  The application body 24 is disposed so as to contact or substantially contact both the drawing roller 23 and the intermediate transfer body 53. The application body 24 is disposed so that the pre-wet liquid 22 supplied to the surface of the application body 24 contacts the surface of the intermediate transfer body 53. The applying body 24 uniformly holds the pre-wet liquid 22 supplied from the drawing roller 23 on the surface, and then applies the pre-wetting liquid 22 to the intermediate transfer body 53. The pre-wet liquid 22 is applied to the toner image T (T53) held on the intermediate transfer member 53 by mutual contact between the pre-wet liquid 22 and the toner image T (T53) held on the intermediate transfer member 53. Will be.

  The surface of the application body 24 and the surface of the intermediate transfer body 53 are substantially the same so that the application body 24 and the intermediate transfer body 53 do not disturb the toner image T (T53) carried on the intermediate transfer body 53. It is driven (followed) to move at a speed of

  As an arrangement method of the application body 24 with respect to the intermediate transfer body 53, there is a method of pressing the surface of the application body 24 against the surface of the intermediate transfer body 53 by pressing the rotation shaft of the application body 24 with a spring or the like. In addition to this method, as an arrangement method of the application body 24 with respect to the intermediate transfer body 53, a ring-shaped indentation amount regulating member having a diameter smaller than the diameter of the application body 24 is provided at both ends of the application body 24, and the indentation is performed. A method of fixing the application body 24 in a state where the amount regulating member is pushed in is also mentioned.

  In addition to these methods, as an arrangement method of the application body 24 with respect to the intermediate transfer body 53, a ring-shaped interval regulating member having a diameter larger than that of the application body 24 is provided at both ends of the application body 24, and the application body 24 is applied. A method of fixing the application body 24 in a state where an appropriate gap is maintained between the body 24 and the intermediate transfer body 53 is also exemplified.

  The scooping roller 23 may be provided with a control mechanism that controls the rotation speed of the scooping roller 23. The control mechanism adjusts the rotation speed of the pumping roller 23 so that the amount of the pre-wet liquid 22 on the surface of the application body 24 is adjusted to an appropriate value. As long as the amount of the pre-wet liquid 22 on the surface of the application body 24 is within an appropriate value, the rotation direction of the scooping roller 23 may be the direction opposite to the arrow A23 direction.

  When the amount of the pre-wet liquid 22 on the surface of the application body 24 is an appropriate value, the pre-wet liquid 22 applied to the toner image T (T53) carried on the surface of the intermediate transfer body 53 is intermediate transfer. This is the amount of the pre-wet liquid 22 that can form a liquid pool that is necessary and sufficient to prevent image disturbance due to the transfer electric field in the upstream portion of the nip portion between the body 53 and the recording medium P. This appropriate amount varies depending on the type of the recording medium P because the amount of the pre-wet liquid 22 absorbed by the recording medium P varies depending on the type of the recording medium P such as recording paper. Therefore, the rotational speed of the scooping roller 23 is adjusted according to the type of the recording medium P.

  The potential difference forming device 24 </ b> V is connected to the application body 24. The potential difference forming device 24 </ b> V generates a potential difference between the surface of the application body 24 and the surface of the intermediate transfer body 53. The value of this potential difference is such that the toner particles are intermediate so that the toner image T (T53) carried on the surface of the intermediate transfer member 53 is not disturbed by contact (or substantially contact) with the coating member 24. The electric field is adjusted so as to remain on the surface of the transfer body 53.

  For example, it is assumed that the toner particles are positively charged in the developing device 40 and the surface of the intermediate transfer member 53 has a negative potential. In this case, the surface of the application body 24 is adjusted to have a higher potential than the surface of the intermediate transfer body 53. The value of the potential is appropriately adjusted according to the charge amount of the toner particles. When the pre-wet liquid 22 is applied to the toner image T (T53) held on the intermediate transfer member 53, the toner image T (T53) held on the intermediate transfer member 53 is caused by the potential difference formed by the potential difference forming device 24V. It is pressed against the surface of the intermediate transfer member 53. This potential difference suppresses the toner image T (T53) from moving toward the applying body 24.

(Operation and effect by the coating mechanism 20)
As described above, before the toner image T (T53) is transferred from the intermediate transfer member 53 to the recording medium P, the coating mechanism 20 is applied to the toner image T (T53) carried on the surface of the intermediate transfer member 53. To apply the pre-wet liquid 22. The toner image T (T53) carried on the surface of the intermediate transfer member 53 is in a state where a large amount of the pre-wet liquid 22 (carrier liquid) is held.

  When the toner image T (T53) passes through the transfer portion U2, a large amount of the pre-wet liquid 22 (carrier liquid) that has been retained does not completely enter the nip portion but accumulates upstream of the nip portion. In the vicinity of the nip portion on the upstream side of the nip portion, a liquid pool is formed by the pre-wet liquid 22 (carrier liquid) (see the liquid pool D in FIG. 5).

  By forming a liquid pool so that the toner particles include a region affected by the transfer electric field on the upstream side of the nip portion, the local movement of the toner particles is suppressed. The toner particles can move to a predetermined position to be moved along with the rotation of the intermediate transfer member 53. As a result, the occurrence of image disturbance can be suppressed, and a recording medium P on which a higher quality image as shown in FIG. 3 is formed (a recording medium P on which a toner image is uniformly transferred) can be obtained. It becomes.

  Further, in the image forming apparatus 100 (see FIG. 9) in the present embodiment, a potential difference is formed between the application body 24 and the intermediate transfer body 53 by the potential difference forming apparatus 24V. The pre-wet liquid 22 is applied to the toner image T (T53) held on the intermediate transfer member 53 by mutual contact between the pre-wet liquid 22 and the toner image T (T53) held on the intermediate transfer member 53. Will be. When the pre-wet liquid 22 is applied to the toner image T (T53) held on the intermediate transfer member 53, the toner image T (T53) held on the intermediate transfer member 53 is formed by the potential difference forming device 24V. It is pressed against the surface of the intermediate transfer member 53 by the potential difference.

  Due to the above-described potential difference, the toner image T (T53) is prevented from moving to the application body 24 side, and the pre-wet liquid 22 and the toner image T (T53) held on the intermediate transfer body 53 are in contact with each other. As a result, the pre-wet liquid 22 is effectively transferred (moved) from the application body 24 side to the intermediate transfer body 53 side. When the pre-wet liquid 22 is transferred (when the pre-wet liquid 22 is applied to the toner image T (T 53)), the toner image T (T 53) carried on the surface of the intermediate transfer body 53 is in contact with the application body 24. It is not disturbed by contact. As a result, the occurrence of image disturbance can be suppressed, and a recording medium P on which a higher quality image as shown in FIG. 3 is formed (a recording medium P on which a toner image is uniformly transferred) can be obtained. It becomes.

(Operation and effect of the image forming apparatus 102)
As described above, in the image forming apparatus 102, the coating mechanism 10 and the coating mechanism 20 are used. The prewetting liquid 12 is supplied to the toner image T (T52) developed on the surface of the photoreceptor 52 by the coating mechanism 10. The prewetting liquid 22 is supplied to the toner image T (T53) carried on the surface of the intermediate transfer member 53 by the coating mechanism 20.

  With this configuration, the occurrence of image disturbance can be suppressed, and a recording medium P on which a higher quality image as shown in FIG. 3 is formed (a recording medium P on which a toner image is uniformly transferred) can be obtained. It becomes possible.

  Image forming apparatus 100 in the present embodiment includes both coating mechanism 10 and coating mechanism 20. Therefore, in the present embodiment, the photoconductor 52 corresponds to an image carrier. The intermediate transfer member 53 corresponds to a member to be transferred. The transfer unit U1 corresponds to the first transfer unit. The transfer unit U2 corresponds to the second transfer unit. The coating mechanism 10 corresponds to a first coating mechanism. The coating mechanism 20 corresponds to a second coating mechanism.

  The pre-wet liquid 12 corresponds to the first pre-wet liquid. The pre-wet liquid 22 corresponds to the second pre-wet liquid. The application body 14 corresponds to a first application body. The application body 24 corresponds to a second application body. The potential difference forming device 14V corresponds to a first potential difference forming device. The potential difference forming device 24V corresponds to a second potential difference forming device.

  The potential difference formed between the surface of the photosensitive member 52 (image carrier) and the surface of the coating body 14 (first coating body) by the potential difference forming apparatus 14V (first potential difference forming apparatus) corresponds to the first potential difference. To do. The potential difference formed between the surface of the intermediate transfer member 53 (transferred member) and the surface of the coating body 24 (second coating body) by the potential difference forming device 24V (second potential difference forming device) is changed to the second potential difference. Equivalent to.

[Embodiment 2]
With reference to FIG. 11, the image forming apparatus in the present embodiment will be described. The image forming apparatus includes an image forming unit 61. The number of image forming units 61 is increased or decreased according to the number of developers used in the image forming apparatus.

  The image forming unit 61 includes a transfer member 51, a photoconductor 52, a coating mechanism 10, a latent image writing unit 52K, and a developing device 40. Unlike the image forming unit 60 (see FIG. 10) in the first embodiment, the image forming unit 61 does not include the intermediate transfer member 53 and the coating mechanism 20.

  The photoreceptor 52 is disposed so as to face the transfer member 51. A transfer portion U1 is formed between the surface of the photoconductor 52 and the surface of the recording medium P that moves along the surface of the photoconductor 52.

  The electrostatic latent image formed on the surface of the photoreceptor 52 by the developing device 40 is developed as a toner image T (T52) by the developer 42. The prewetting liquid 12 is supplied to the toner image T (T52) developed on the surface of the photoreceptor 52 by the coating mechanism 10 as in the case of the first embodiment.

  Thereafter, the toner image T (T52) is transferred from the photosensitive member 52 to the recording medium P in the transfer portion U1 by a transfer electric field formed between the transfer member 51 and the photosensitive member 52 by the potential difference forming device 52V. As described above, the printing operation is completed.

(Action / Effect)
As in the case of the above-described first embodiment, before the toner image T (T52) is transferred from the photoconductor 52 to the recording medium P, the toner image T (T52) carried on the surface of the photoconductor 52 is The prewetting liquid 12 is applied by the application mechanism 10. The toner image T (T52) carried on the surface of the photoreceptor 52 is in a state where a large amount of the pre-wet liquid 12 (carrier liquid) is held.

  When the toner image T (T52) passes through the transfer portion U1, a large amount of the pre-wet liquid 12 (carrier liquid) that has been retained does not enter the nip portion but accumulates upstream of the nip portion. In the vicinity of the nip portion on the upstream side of the nip portion, a liquid pool is formed by the pre-wet liquid 12 (carrier liquid) (see the liquid pool D in FIG. 5).

  By forming a liquid pool so that the toner particles include a region affected by the transfer electric field on the upstream side of the nip portion, the local movement of the toner particles is suppressed. The toner particles can move to a predetermined position where the toner particles should move as the photoconductor 52 rotates. As a result, the occurrence of image disturbance can be suppressed, and a recording medium P on which a higher quality image as shown in FIG. 3 is formed (a recording medium P on which a toner image is uniformly transferred) can be obtained. It becomes.

  Furthermore, in the image forming apparatus according to the present embodiment, a potential difference is formed between the coated body 14 and the photoreceptor 52 by the potential difference forming device 14V. Due to this potential difference, the toner image T (T52) is suppressed from moving toward the application body 14, and the pre-wet liquid 12 and the toner image T (T52) held on the photoconductor 52 are brought into contact with each other, The pre-wet liquid 12 is effectively transferred (moved) from the coated body 14 side to the photosensitive body 52 side. When the pre-wet liquid 12 is transferred (when the pre-wet liquid 12 is applied to the toner image T (T52)), the toner image T (T52) carried on the surface of the photoreceptor 52 is in contact with the application body 14. Will not be disturbed.

  Therefore, according to the image forming apparatus of the present embodiment, it is possible to suppress the occurrence of image disturbance, and the recording medium P (toner image is uniformly transferred) on which a higher quality image as shown in FIG. 3 is formed. Recorded recording medium P) can be obtained.

  The image forming apparatus according to the present embodiment includes the coating mechanism 10 but does not include the coating mechanism 20 according to the above-described first embodiment. Therefore, in the present embodiment, the photoconductor 52 corresponds to an image carrier. The recording medium P corresponds to a member to be transferred. The transfer unit U1 corresponds to the first transfer unit. The coating mechanism 10 corresponds to a first coating mechanism.

  The pre-wet liquid 12 corresponds to the first pre-wet liquid. The application body 14 corresponds to a first application body. The potential difference forming device 14V corresponds to a first potential difference forming device. The potential difference formed between the surface of the photosensitive member 52 (image carrier) and the surface of the coating body 14 (first coating body) by the potential difference forming apparatus 14V (first potential difference forming apparatus) corresponds to the first potential difference. To do.

[Embodiment 3]
With reference to FIG. 12, an image forming apparatus according to the present embodiment will be described. The image forming apparatus includes an image forming unit 62. The number of image forming units 62 is increased or decreased according to the number of developers used in the image forming apparatus.

  In the image forming unit 62, unlike the image forming unit 60 (see FIG. 10) in the first embodiment, only the coating mechanism 20 is used, and the coating mechanism 10 is not used.

(Action / Effect)
Before the toner image T (T53) is transferred from the intermediate transfer member 53 to the recording medium P, the prewetting liquid 22 is applied to the toner image T (T53) carried on the surface of the intermediate transfer member 53 by the coating mechanism 20. Applied. The toner image T (T53) carried on the surface of the intermediate transfer member 53 is in a state where a large amount of the pre-wet liquid 22 (carrier liquid) is held.

  When the toner image T (T53) passes through the transfer portion U2, a large amount of the pre-wet liquid 22 (carrier liquid) that has been retained does not completely enter the nip portion but accumulates upstream of the nip portion. In the vicinity of the nip portion on the upstream side of the nip portion, a liquid pool is formed by the pre-wet liquid 22 (carrier liquid) (see the liquid pool D in FIG. 5).

  By forming a liquid pool so that the toner particles include a region affected by the transfer electric field on the upstream side of the nip portion, the local movement of the toner particles is suppressed. The toner particles can move to a predetermined position to be moved along with the rotation of the intermediate transfer member 53. As a result, the occurrence of image disturbance can be suppressed, and a recording medium P on which a higher quality image as shown in FIG. 3 is formed (a recording medium P on which a toner image is uniformly transferred) can be obtained. It becomes.

  Further, in the image forming apparatus according to the present embodiment, a potential difference is formed between the coated body 24 and the intermediate transfer body 53 by the potential difference forming device 24V. Due to this potential difference, the toner image T (T53) is suppressed from moving to the application body 24 side, and the pre-wet liquid 22 and the toner image T (T53) held on the intermediate transfer body 53 are brought into contact with each other. The pre-wet liquid 22 is effectively transferred (moved) from the application body 24 side to the intermediate transfer body 53 side. When the pre-wet liquid 22 is transferred (when the pre-wet liquid 22 is applied to the toner image T (T 53)), the toner image T (T 53) carried on the surface of the intermediate transfer body 53 is in contact with the application body 24. It is not disturbed by contact.

  Therefore, according to the image forming apparatus of the present embodiment, it is possible to suppress the occurrence of image disturbance, and the recording medium P (toner image is uniformly transferred) on which a higher quality image as shown in FIG. 3 is formed. Recorded recording medium P) can be obtained.

  The image forming apparatus according to the present embodiment includes the application mechanism 20, but does not include the application mechanism 10 according to the first embodiment. Therefore, in the present embodiment, the intermediate transfer member 53 corresponds to an image carrier. The recording medium P corresponds to a member to be transferred. The transfer unit U2 corresponds to the first transfer unit. The coating mechanism 20 corresponds to the first coating mechanism.

  The pre-wet liquid 22 corresponds to the first pre-wet liquid. The application body 24 corresponds to the first application body. The potential difference forming device 24V corresponds to the first potential difference forming device. The potential difference formed between the surface of the intermediate transfer member 53 (image carrier) and the surface of the coating member 24 (first coating member) by the potential difference forming device 24V (first potential difference forming device) becomes the first potential difference. Equivalent to.

[Embodiment 4]
With reference to FIG. 13, an image forming apparatus according to the present embodiment will be described. The image forming apparatus includes an image forming unit 63. The number of image forming units 63 is increased or decreased according to the number of developing solutions used in the image forming apparatus.

  In the image forming unit 63, unlike the image forming unit 60 (see FIG. 10) in the first embodiment described above, only the coating mechanism 10 is used, and the coating mechanism 20 is not used.

(Action / Effect)
Before the toner image T (T52) is transferred from the photosensitive member 52 to the intermediate transfer member 53, the prewetting liquid 12 is applied to the toner image T (T52) carried on the surface of the photosensitive member 52 by the coating mechanism 10. Is done. The toner image T (T52) carried on the surface of the photoreceptor 52 is in a state where a large amount of the pre-wet liquid 12 (carrier liquid) is held.

  When the toner image T (T52) passes through the transfer portion U1, a large amount of the pre-wet liquid 12 (carrier liquid) that has been retained does not enter the nip portion but accumulates upstream of the nip portion. In the vicinity of the nip portion on the upstream side of the nip portion, a liquid pool is formed by the pre-wet liquid 12 (carrier liquid) (see the liquid pool D in FIG. 8).

  By forming a liquid pool so that the toner particles include a region affected by the transfer electric field on the upstream side of the nip portion, the local movement of the toner particles is suppressed. The toner particles can move to a predetermined position where the toner particles should move as the photoconductor 52 rotates. As a result, the occurrence of image disturbance can be suppressed, and a recording medium P on which a higher quality image as shown in FIG. 3 is formed (a recording medium P on which a toner image is uniformly transferred) can be obtained. It becomes.

  Furthermore, in the image forming apparatus according to the present embodiment, a potential difference is formed between the coated body 14 and the photoreceptor 52 by the potential difference forming device 14V. Due to this potential difference, the toner image T (T52) is suppressed from moving toward the application body 14, and the pre-wet liquid 12 and the toner image T (T52) held on the photoconductor 52 are brought into contact with each other, When the pre-wet liquid 12 is transferred (when the pre-wet liquid 12 is applied to the toner image T (T52)), the toner image T (T52) carried on the surface of the photoreceptor 52 is in contact with the application body 14. Will not be disturbed.

  Therefore, according to the image forming apparatus of the present embodiment, it is possible to suppress the occurrence of image disturbance, and the recording medium P (toner image is uniformly transferred) on which a higher quality image as shown in FIG. 3 is formed. Recorded recording medium P) can be obtained.

  The image forming apparatus according to the present embodiment includes the coating mechanism 10 but does not include the coating mechanism 20 according to the above-described first embodiment. Therefore, in the present embodiment, the photoconductor 52 corresponds to an image carrier. The intermediate transfer member 53 corresponds to a member to be transferred. The transfer unit U1 corresponds to the first transfer unit. The coating mechanism 10 corresponds to a first coating mechanism.

  The pre-wet liquid 12 corresponds to the first pre-wet liquid. The application body 14 corresponds to a first application body. The potential difference forming device 14V corresponds to a first potential difference forming device. The potential difference formed between the surface of the photosensitive member 52 (image carrier) and the surface of the coating body 14 (first coating body) by the potential difference forming apparatus 14V (first potential difference forming apparatus) corresponds to the first potential difference. To do.

[Embodiment 5]
With reference to FIG. 14, an image forming apparatus according to the present embodiment will be described. The image forming apparatus includes an image forming unit 64. The number of image forming units 64 is increased or decreased according to the number of developers used in the image forming apparatus.

  In the image forming unit 64, in addition to the configuration of the image forming unit 62 (see FIG. 12) in the above-described third embodiment, the coating mechanism 30 is used.

(Coating mechanism 30)
The coating mechanism 30 is disposed so as to face the surface of the intermediate transfer member 53. The application mechanism 30 applies the pre-wet liquid 32 to the surface of the intermediate transfer member 53 on the upstream side of the transfer unit U1 in the movement direction (arrow A53 direction) of the surface of the intermediate transfer member 53.

  Specifically, the application mechanism 30 includes a supply tank 31, a pre-wet liquid 32, a scooping roller 33, and an application body 34. A pre-wet liquid 32 for application to the intermediate transfer member 53 is stored in the supply tank 31.

  The pre-wet liquid 32 is a liquid that can disperse toner particles in the liquid. The pre-wet liquid 32 moves the toner image T (T52) from the photosensitive member 52 to the intermediate transfer member by moving toner particles in the transfer portion U1 in the portion where the transfer electric field is formed. It is a liquid that can be transferred to 53.

  As the pre-wet liquid 32, for example, a liquid having the same material as the carrier liquid contained in the developer 42 can be used. The prewetting liquid 32 is replenished to the supply tank 31 from a supply device (not shown) as necessary.

  The scooping roller 33 rotates in the direction of arrow A33. The pumping roller 33 pumps the pre-wet liquid 32 from the supply tank 31. As the drawing-up roller 33, for example, a roller having an uneven shape on the surface, such as an anilox roller, can be used.

  The application body 34 rotates in the direction of arrow A34. The prewetting liquid 32 pumped up by the pumping roller 33 is supplied to the surface of the application body 34. As the application body 34, a roller capable of holding an appropriate amount of the pre-wet liquid 32 on the surface thereof is used. A cleaning blade 33T that abuts on the surface of the pumping roller 33 may be provided at a position upstream of the nip portion formed between the pumping roller 33 and the application body 34.

  The application body 34 is disposed so as to contact or substantially contact both the drawing roller 33 and the intermediate transfer body 53. The application body 34 is disposed so that the pre-wet liquid 32 supplied to the surface of the application body 34 contacts the surface of the intermediate transfer body 53. The applying body 34 uniformly holds the pre-wet liquid 32 supplied from the scooping roller 33 on the surface, and then applies it to the surface of the intermediate transfer body 53.

  The application body 34 and the intermediate transfer body 53 are preferably driven (driven) so that the surface of the application body 34 and the surface of the intermediate transfer body 53 move at substantially the same speed.

  As an arrangement method of the application body 34 with respect to the intermediate transfer body 53, there is a method of pressing the surface of the application body 34 against the surface of the intermediate transfer body 53 by pressing the rotation shaft of the application body 34 with a spring or the like. In addition to this method, as an arrangement method of the application body 34 with respect to the intermediate transfer body 53, a ring-shaped indentation amount regulating member having a diameter smaller than the diameter of the application body 34 is provided at both ends of the application body 34, and the indentation is performed. A method of fixing the application body 34 in a state where the amount regulating member is pushed in is also mentioned.

  In addition to these methods, as an arrangement method of the application body 34 with respect to the intermediate transfer body 53, a ring-shaped interval regulating member having a diameter larger than the diameter of the application body 34 is provided at both ends of the application body 34, and the application body 34 is applied. A method of fixing the application body 34 in a state where an appropriate gap is maintained between the body 34 and the intermediate transfer body 53 is also exemplified.

  The scooping roller 33 may be provided with a control mechanism that controls the rotation speed of the scooping roller 33. The control mechanism adjusts the rotation speed of the pumping roller 33 so that the amount of the pre-wet liquid 32 on the surface of the application body 34 is adjusted to an appropriate value. As long as the amount of the pre-wet liquid 32 on the surface of the application body 34 is in an appropriate range, the rotation direction of the scooping roller 33 may be the direction opposite to the arrow A33 direction.

  The appropriate amount of the pre-wet liquid 32 on the surface of the application body 34 means that the pre-wet liquid 32 on the surface of the application body 34 is upstream of the nip portion between the photoconductor 52 and the intermediate transfer body 53. The amount of the pre-wet liquid 32 that can form a liquid pool of an amount necessary and sufficient to prevent image disturbance due to the transfer electric field.

(Operation / effect by the coating mechanism 30)
As described above, the prewetting liquid 32 is applied to the surface of the intermediate transfer body 53 by the application mechanism 30 on the upstream side of the transfer portion U1 in the movement direction (arrow A53 direction) of the surface of the intermediate transfer body 53. . A toner image used for image formation is not formed on the surface of the intermediate transfer member 53 to which the pre-wet liquid 32 is supplied. In the coating mechanism 30, it is not necessary to form a potential difference between the coating body 34 and the intermediate transfer body 53, and the prewetting liquid 32 can be applied to the intermediate transfer body 53 as it is.

  The pre-wet liquid 32 (carrier liquid) is supplied to the upstream part of the transfer part U1. When the toner image T (T52) carried on the surface of the photoconductor 52 enters the transfer portion U1, the pre-wet liquid 32 is supplied to the toner image T (T52) carried on the surface of the photoconductor 52. Is done. The toner image T (T52) is in a state where a large amount of the pre-wet liquid 32 (carrier liquid) is held.

  When the toner image T (T52) passes through the transfer portion U1, a large amount of the pre-wet liquid 32 that has been retained does not enter the nip portion but accumulates upstream of the nip portion. In the vicinity of the nip portion on the upstream side of the nip portion, a good liquid pool is formed by the pre-wet liquid 32 (see the liquid pool D in FIG. 8).

  By forming a liquid pool so that the toner particles include a region affected by the transfer electric field on the upstream side of the nip portion, the local movement of the toner particles is suppressed. The toner particles can move to a predetermined position where the toner particles should move as the photoconductor 52 rotates.

  Therefore, according to the image forming apparatus of the present embodiment, it is possible to suppress the occurrence of image disturbance, and the recording medium P (toner image is uniformly transferred) on which a higher quality image as shown in FIG. 3 is formed. Recorded recording medium P) can be obtained.

  The image forming apparatus according to the present embodiment includes the application mechanism 20, but does not include the application mechanism 10 according to the first embodiment. Therefore, in the present embodiment, the intermediate transfer member 53 corresponds to an image carrier. The recording medium P corresponds to a member to be transferred. The transfer unit U2 corresponds to the first transfer unit. The transfer part U1 corresponds to a second transfer part. The coating mechanism 20 corresponds to the first coating mechanism.

  The pre-wet liquid 22 corresponds to the first pre-wet liquid. The application body 24 corresponds to the first application body. The potential difference forming device 24V corresponds to the first potential difference forming device. The potential difference formed between the surface of the intermediate transfer member 53 (image carrier) and the surface of the coating member 24 (first coating member) by the potential difference forming device 24V (first potential difference forming device) becomes the first potential difference. Equivalent to. The pre-wet liquid 32 corresponds to a third pre-wet liquid. The coating mechanism 30 corresponds to a third coating mechanism.

[Embodiment 6]
With reference to FIG. 15, the image forming apparatus in the present embodiment will be described. The image forming apparatus includes an image forming unit 65. FIG. 15 partially shows the image forming unit 65. The number of image forming units 65 is increased or decreased according to the number of developers used in the image forming apparatus.

  In the image forming unit 65, a coating mechanism 20A is used instead of the coating mechanism 20 (see FIG. 10 and the like) in each of the above-described embodiments. In the coating mechanism 20 </ b> A, the surface layer 24 </ b> S having an appropriate resistance is applied to the coating body 24 (core metal) so that a potential difference can be easily formed between the surface of the coating body 24 and the surface of the intermediate transfer body 53. Provided on the surface.

  As a member constituting the surface layer 24S, rubber such as urethane rubber or NBR (Nitrile Butadiene Rubber), or sponge such as foamed urethane, foamed melamine, or foamed polyethylene may be used.

  Even when such a coating mechanism 20A is used instead of the coating mechanism 20 (see FIG. 10 and the like), it is possible to suppress the occurrence of image disturbance, as in the operations and effects in the above-described embodiments. Thus, it is possible to obtain a recording medium P on which a higher quality image as shown in FIG. 3 is formed (recording medium P on which the toner image is uniformly transferred). The configuration in which the surface layer 24S is provided in the coating mechanism 20A may be employed in the coating mechanism 10 (see FIG. 10 and the like).

[Embodiment 7]
With reference to FIG. 16, the image forming apparatus in the present embodiment will be described. The image forming apparatus includes an image forming unit 66. FIG. 16 partially shows the image forming unit 66. The number of image forming units 66 is increased or decreased according to the number of developers used in the image forming apparatus.

  In the image forming unit 66, in addition to the configuration of the coating mechanism 20A (see FIG. 15) in the above-described sixth embodiment, a toner particle charging unit 25M is used.

  The toner particle charging unit 25M is disposed so as to face the intermediate transfer member 53 on the upstream side in the moving direction (arrow A53 direction) of the surface of the intermediate transfer member 53 with respect to the coating mechanism 20A. The toner particle charging unit 25M is, for example, a corona charger. The toner particle charging unit 25M enhances the charging of the toner particles in the toner image T (T53).

  There are cases where the charging of the toner particles by the developing device 40 is weak. In addition, the charge on the toner particles may be weakened. In these cases, the toner image T (T53) may be disturbed when the pre-wet liquid 22 is applied only by the potential difference formed between the coating mechanism 20A and the intermediate transfer member 53 by the potential difference forming device 24V. is there.

  In the image forming unit 66 of this embodiment, the toner particle charging unit 25M enhances the charging of the toner particles in the toner image T (T53). It is possible to prevent the toner image T (T53) from being disturbed when the pre-wet liquid 22 is applied.

  If the toner particles in the toner image T (T53) are excessively charged, there is a case where an unintended influence is exerted on the subsequent transfer. In order to suppress this, toner particle charging means 25N may be further used.

  The toner particle charging unit 25N is disposed so as to face the intermediate transfer member 53 on the downstream side in the movement direction (arrow A53 direction) of the surface of the intermediate transfer member 53 with respect to the coating mechanism 20A. The toner particle charging means 25N is, for example, a corona charger. The toner particle charging means 25N weakens the charging of the toner particles in the toner image T (T53). Even when the charging of the toner particles in the toner image T (T53) is excessively strengthened, it is possible to prevent the toner particle charging unit 25N from causing an unintended influence on the subsequent transfer. Become.

  The configuration in which the toner particle charging unit 25M is provided in the coating mechanism 20A can also be employed in the coating mechanism 10 (see FIG. 10 and the like) and the coating mechanism 20 (see FIG. 10 and the like). A configuration in which toner particle charging means 25N is further provided in the application mechanism 20A can also be employed in the application mechanism 10 (see FIG. 10 and the like) and the application mechanism 20 (see FIG. 10 and the like).

[Embodiment 8]
With reference to FIG. 17, an image forming apparatus according to the present embodiment will be described. The image forming apparatus includes an image forming unit 67. FIG. 17 partially shows the image forming unit 67. The number of image forming units 67 is increased or decreased according to the number of developers used in the image forming apparatus.

  In the image forming unit 67, a coating mechanism 20B is used instead of the coating mechanism 20 (see FIG. 10 and the like) in each of the above-described embodiments. In the application mechanism 20B, an application belt 70 (application body) is used.

  The application belt 70 is configured as an endless belt. The coating belt 70 is formed of a member having an appropriate resistance so that an appropriate amount of the pre-wet liquid 22 can be held on the surface and a potential difference can be formed between the surface and the surface of the intermediate transfer body 53. .

  The coating belt 70 is stretched by the voltage application roller 27 that rotates in the direction of arrow A27 and the stretching roller 26 that rotates in the direction of arrow A26. The application belt 70 is rotationally driven by the voltage application roller 27 and the stretching roller 26.

  The prewetting liquid 22 is pumped up from the supply tank 21 by a part of the coating belt 70. The coating belt 70 is disposed so as to contact or substantially contact the intermediate transfer member 53. The coating belt 70 is disposed so that the pre-wet liquid 22 supplied to the surface of the coating belt 70 contacts the surface of the intermediate transfer member 53. The coating belt 70 is applied to the intermediate transfer member 53 after holding the pre-wet liquid 22 uniformly on the surface. The pre-wet liquid 22 is applied to the toner image T (T53) held on the intermediate transfer member 53 by mutual contact between the pre-wet liquid 22 and the toner image T (T53) held on the intermediate transfer member 53. Will be.

  The surface of the coating belt 70 and the surface of the intermediate transfer member 53 are substantially the same so that the coating belt 70 and the intermediate transfer member 53 do not disturb the toner image T (T53) carried on the intermediate transfer member 53. It is driven to move at a speed of.

  The voltage application roller 27 is provided with a potential difference generator 27V. A potential difference is formed between the coating belt 70 and the intermediate transfer member 53 by the potential difference generator 27V. When the pre-wet liquid 22 is applied to the toner image T (T53) held on the intermediate transfer member 53, the toner image T (T53) held on the intermediate transfer member 53 is caused by the potential difference formed by the potential difference generating device 27V. It is pressed against the surface of the intermediate transfer member 53. This potential difference suppresses the toner image T (T53) from moving toward the application belt 70 side.

  The application belt 70 may be provided with a liquid amount adjusting roller 28 that rotates in the direction of arrow A28 and a liquid amount adjusting roller 29 that rotates in the direction of arrow A29. The amount of pre-wet liquid 22 is adjusted to an appropriate value by the liquid amount adjusting rollers 28 and 29. A cleaning blade 28T may be provided downstream of the nip portion of the liquid amount adjusting roller 28 in the rotation direction of the liquid amount adjusting roller 28.

  Also with this configuration, the occurrence of image disturbance can be suppressed, and a recording medium P (recording medium P on which a toner image is uniformly transferred) on which a higher quality image as shown in FIG. 3 is formed can be obtained. Is possible.

  The configuration in which the coating mechanism 20B is provided instead of the coating mechanism 20 (see FIG. 10 and the like) can also be adopted in the coating mechanism 10 (see FIG. 10 and the like) and the coating mechanism 20A (see FIG. 16 and the like).

  As mentioned above, although each embodiment based on this invention was described, each embodiment disclosed this time is an illustration and restrictive at no points. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Transfer member, 2 Image carrier, 3 Intermediate transfer body, 7 Paper conveyance roller 10, 20, 20A, 20B, 30 Coating mechanism, 11, 21, 31 Supply tank, 12, 22, 32 Pre-wet liquid, 13, 23, 33 Pumping roller, 13T, 23T, 28T, 33T, 45T, 52T, 53T Cleaning blade, 14, 24, 34 Application body, 14V, 24V, 52V Potential difference forming device, 17 Paper feeding device, 18 Fixing device, 19 Ejection Paper device, 24S surface layer, 25M, 25N toner particle charging means, 26 stretching roller, 27 voltage application roller, 27V potential difference generating device, 28, 29 liquid amount adjusting roller, 40 developing device, 41 developing tank, 42 developer, 43 Supply roller, 43T regulating blade, 44 leveling roller, 45 developer carrier, 45M developer Jar, 45V, 51V, 53V voltage application device, 52 photoconductor, 52K latent image writing unit, 60, 61, 62, 63, 64, 65, 66, 67 image forming unit, 70 coating belt, 100, 101, 102 image Forming device, AR transport direction, C carrier liquid, E, R region, H1, H2, H3, H4 amount, N nip part, P recording medium, Q, S, U1, U2 transfer part, T, T52, T53 toner image .

Claims (7)

An image forming apparatus for forming an image on a recording medium using a developer in which toner particles are dispersed in a carrier liquid,
A developing device for forming a toner image from the developer;
An image carrier for moving the toner image while holding the toner image;
The toner image that is formed between the surface of the image carrier and the surface of the transfer member that moves along the surface of the image carrier, and is held by the image carrier, is transferred to the transfer member. A first transfer section;
A first pre-wet liquid is disposed on the surface of the image carrier, and the first pre-wet liquid is applied to the toner image held on the image carrier upstream of the first transfer portion in the moving direction of the toner image. A first application mechanism for applying,
The first application mechanism includes:
A first application body to which the first prewetting liquid is supplied on the surface;
A first potential difference forming device that forms a first potential difference between the surface of the image carrier and the surface of the first application body,
The first application body is disposed so that the first pre-wet liquid supplied to the surface of the first application body contacts the surface of the image carrier,
The image carrier and the first application body are driven so that the surface of the image carrier and the surface of the first application body move at substantially the same speed,
The first pre-wet liquid is applied to the toner image held on the image carrier by mutual contact between the first pre-wet liquid and the toner image held on the image carrier,
When the first pre-wetting liquid is applied to the toner image held on the image carrier, the toner image held on the image carrier is pressed against the surface of the image carrier by the first potential difference. Being
Image forming apparatus. The first application mechanism adjusts the amount of the first pre-wet liquid and then adjusts the amount of the toner image held on the image carrier upstream of the first transfer portion in the moving direction of the toner image. And applying the first prewetting liquid,
The image forming apparatus according to claim 1. The first application mechanism adjusts the amount of the first pre-wet liquid according to the type of the recording medium.
The image forming apparatus according to claim 2. The first pre-wet liquid is the same material as the carrier liquid.
The image forming apparatus according to claim 1. The image carrier is a photoreceptor arranged to face the developing device.
The image forming apparatus according to claim 1. The transfer member is an intermediate transfer member arranged to face the photoconductor,
The toner image formed between the surface of the intermediate transfer member and the surface of the recording medium moving along the surface of the intermediate transfer member, and the toner image held on the intermediate transfer member is transferred to the recording medium. 2 transfer sections;
A second pre-wet liquid is applied to the toner image that is disposed so as to face the surface of the intermediate transfer member and is held by the intermediate transfer member on the upstream side of the second transfer portion in the moving direction of the toner image. A second application mechanism for applying,
The second application mechanism includes:
A second application body on the surface of which the second prewetting liquid is supplied;
A second potential difference forming device that forms a second potential difference between the surface of the intermediate transfer body and the surface of the second application body,
The second application body is arranged so that the second pre-wet liquid supplied to the surface of the second application body contacts the surface of the intermediate transfer body,
The intermediate transfer body and the second application body are driven so that the surface of the intermediate transfer body and the surface of the second application body move at substantially the same speed,
The second pre-wet liquid is applied to the toner image held on the intermediate transfer body by mutual contact between the second pre-wet liquid and the toner image held on the intermediate transfer body,
When the second pre-wet liquid is applied to the toner image held on the intermediate transfer member, the toner image held on the intermediate transfer member is pressed against the surface of the intermediate transfer member by the second potential difference. Being
The image forming apparatus according to claim 5. The image carrier is an intermediate transfer member,
A photoconductor disposed to face both the developing device and the intermediate transfer member;
A second transfer portion formed between the surface of the photosensitive member and the surface of the intermediate transfer member, and the toner image held on the photosensitive member is transferred to the intermediate transfer member;
A third pre-wet liquid is applied to the surface of the intermediate transfer member, which is disposed so as to face the surface of the intermediate transfer member and upstream of the second transfer portion in the movement direction of the surface of the intermediate transfer member. A third application mechanism,
The image forming apparatus according to claim 1.

Images