JP5493989B2 - Image forming apparatus and processing liquid coating apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus and a processing liquid coating apparatus.

  As an image forming apparatus such as a printer, a facsimile machine, a copying machine, a plotter, and a complex machine of these, for example, a liquid discharge recording type image forming apparatus using a recording head for discharging ink droplets is known. This liquid discharge recording type image forming apparatus means that ink droplets are transported from a recording head (not limited to paper, including OHP, and can be attached to ink droplets and other liquids). Yes, it is also ejected onto a recording medium or a recording medium, recording paper, recording paper, etc.) to form an image (recording, printing, printing, and printing are also used synonymously). And a serial type image forming apparatus that forms an image by ejecting liquid droplets while the recording head moves in the main scanning direction, and a line type head that forms images by ejecting liquid droplets without moving the recording head There are line type image forming apparatuses using

  In the present application, the “image forming apparatus” of the liquid ejection method is an apparatus that forms an image by ejecting liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, or the like. In addition, “image formation” means not only that an image having a meaning such as a character or a figure is imparted to the medium but also an image having no meaning such as a pattern is imparted to the medium (simply liquid. It also means that a droplet hits the medium). The “ink” is not limited to what is called ink, and is not particularly limited as long as it becomes a liquid when ejected. For example, a DNA sample, a resist, a pattern material, etc. Is also included. In addition, the “image” is not limited to a planar one, but includes an image given to a three-dimensionally formed image, and an image formed by three-dimensionally modeling a solid itself. In addition, the “image forming apparatus” is not limited to the liquid discharge type, but includes an apparatus that forms an image using an electrophotographic method.

  In such a liquid ejection type image forming apparatus, in order to form an image by forming ink containing a coloring material into droplets, feathering in which dots formed by the droplets are disturbed, and ink droplets of different colors When the ink is struck on the paper adjacent to each other, it may cause problems such as color bleeding, which causes the colors to mix with each other and the color boundary to become unclear. There is a problem that it takes.

  Therefore, as described in Patent Document 1, a pretreatment liquid that reacts with ink to prevent bleeding is applied by an application roller as described in the prior art, or the pretreatment liquid is ejected as described in Patent Document 2. A mist is applied from the head for application (see also Patent Document 3). An apparatus for applying a treatment liquid in a foam is also known (Patent Document 4).

JP 2002-137378 A Japanese Patent Laying-Open No. 2005-138502 JP 2003-205673 A JP 2009-012394 A

  However, when the processing liquid is applied to the recording medium with the roller, the excess processing liquid that has not been applied swells from the roller peripheral surface at both ends of the roller and expands into a ring shape, and the liquid scatters. There is a problem.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce scattering of liquid when a processing liquid is applied to a recording medium with a roller.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
Image forming means for forming an image on a recording medium;
A coating apparatus for coating a treatment liquid on the recording medium,
The coating apparatus includes at least a transport roller that transports the recording medium, a coating roller that applies a processing liquid to the recording medium, and a squeeze roller that thins the film of the processing liquid on the coating roller; Supply means for supplying the treatment liquid onto the application roller and the squeeze roller,
The supply means includes a supply head disposed so as to contact the application roller and the squeeze roller to form a space on the two rollers, and a suction means connected to the supply head,
When supplying the processing liquid onto the application roller and the squeeze roller, the suction unit is operated to create a negative pressure in the space in the supply head from the gap between the supply head, the application roller, and the squeeze roller. The supply head is controlled to suck air.

  Here, the suction liquid can be sucked from above the space of the supply head to supply the processing liquid into the supply head.

  A suction port of the suction unit, the unit having a means for detecting a liquid level of the processing liquid in the supply head, controlling the supply of the processing liquid so that an air layer is formed in a space in the supply head; Can be configured to be provided at a site where the air layer is formed.

  In addition, a storage unit that stores the processing liquid supplied to the space in the supply head may be provided, and the storage unit may be disposed at a position lower than the space of the supply head.

The treatment liquid coating apparatus according to the present invention is:
In a processing liquid application apparatus for applying a processing liquid to a recording medium,
At least a transport roller for transporting the recording medium, a coating roller for coating a processing liquid on the recording medium, a squeeze roller for thinning a film of the processing liquid on the coating roller, and the processing liquid Supply means for supplying onto the application roller and the squeeze roller,
The supply means includes a supply head disposed so as to contact the application roller and the squeeze roller to form a space on the two rollers, and a suction means connected to the supply head,
When supplying the processing liquid onto the application roller and the squeeze roller, the suction unit is operated to create a negative pressure in the space in the supply head from the gap between the supply head, the application roller, and the squeeze roller. The control is performed to suck air into the supply head.

  According to the image forming apparatus according to the present invention and the processing liquid coating apparatus according to the present invention, the supply head disposed so as to contact the coating roller and the squeeze roller to form a space on the two rollers, and the supply head A suction unit connected to the coating roller and the squeeze roller, when the processing liquid is supplied to the coating roller and the squeeze roller, the suction unit is operated to create a negative pressure in the space between the supply head, the coating roller, and the squeeze roller. Since the control for sucking air into the supply head from the gap is performed, it is possible to reduce the scattering of the liquid when the processing liquid is applied to the recording medium with a roller with a simple structure.

1 is an overall configuration diagram illustrating an example of an image forming apparatus including a processing liquid coating apparatus according to a first embodiment of the present invention. It is typical side surface explanatory drawing of the application part of the process liquid coating device. It is typical explanatory drawing of the process liquid supply part of the process liquid coating device. It is a perspective explanatory view of the application part. FIG. 5 is a cross-sectional explanatory view taken along line AA in FIG. 4. It is side surface explanatory drawing similar to FIG. FIG. 5 is a cross-sectional explanatory view taken along line BB in FIG. 4. It is a flowchart with which it uses for description of application | coating operation | movement by the coating device. 6 is a schematic side explanatory view of a coating portion of Comparative Example 1. FIG. It is a perspective explanatory view of the roller part of the application part of the comparative example 1. It is a plane explanatory view of a roller part similarly. 10 is a schematic side explanatory view of an application part of Comparative Example 2. FIG. It is typical explanatory drawing with which it uses for description of the other example of the supply part of the process liquid coating device of this invention. FIG. 6 is a flowchart for explaining a printing operation of the image forming apparatus. FIG. 15 is a flowchart for explaining a printing operation subsequent to FIG. 14. FIG. 16 is a flowchart for explaining processing liquid supply end operation following FIG. 15. It is a flowchart with which it uses for description of the printing mode without application following FIG.

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of an image forming apparatus according to the present invention including the first embodiment of a coating apparatus according to the present invention will be described with reference to FIG. FIG. 1 is an overall configuration diagram of the image forming apparatus.
The image forming apparatus accommodates a recording head unit 101 as an image forming unit that forms an image by ejecting liquid droplets onto a sheet 100 that is a recording medium, a conveyance belt 102 that conveys the sheet 100, and the sheet 100. A paper feed tray 103 and a processing liquid coating apparatus 200 according to the present invention, which is also a coating means for coating a processing liquid on the paper 100 that is a member to be coated on the upstream side of the recording head unit 101 in the paper transport direction, are provided.

  The recording head unit 101 is composed of a line type liquid discharge head having a nozzle row in which a plurality of nozzles for discharging droplets are arranged in a length corresponding to the paper width. Yellow (Y), magenta (M), cyan The recording heads 101y, 101m, 101c, and 101k are provided with ink droplets of each color of (C) and black (K). Note that the recording head can be mounted on the carriage as a serial type image forming apparatus.

  The conveyor belt 102 is an endless belt, and is configured to circulate between the conveyor roller 121 and the tension roller 122. The paper 100 can be held on the transport belt 102 by, for example, a configuration that performs electrostatic suction, suction by air suction, or other known transport means. Further, a conveying means using a roller pair can also be used.

  The sheets 100 stored in the sheet feeding tray 103 are separated and fed one by one by a pickup roller 131 and sent to a registration roller pair 133 by a conveyance roller pair 132. The registration roller pair 133 causes the sheet 100 to be conveyed by a conveyance roller pair 134 at a predetermined timing. It is sent to the coating apparatus 200 via the transport path 135, and the processing liquid is applied by the processing liquid coating apparatus 200, and is sent and held on the transport belt 102.

  Then, it is conveyed by the circular movement of the conveyor belt 102, droplets of each color are ejected from the head unit 101, an image is formed, and then ejected to the ejection tray 104.

  The treatment liquid coating apparatus 200 includes a container (treatment liquid tank) 202 that contains a treatment liquid (setting agent) 201 and a coating unit 208 that applies the treatment liquid 201 supplied from the container 202 to a sheet 100 that is a recording medium. Etc.

  Here, the treatment liquid 201 is a modifying material that modifies the surface of the paper 100 by being applied to the surface of the paper 100. For example, the treatment liquid 201 is applied in advance to the paper 100 (not limited to paper as a material as described above) without unevenness, so that moisture of the ink can quickly permeate the paper 100 and increase the color component. Fixing agent (setting agent) that prevents bleeding (feathering, bleeding, etc.) and back-through by increasing viscosity and further drying, and increases productivity (number of images output per unit time). is there.

  In terms of composition, this treatment liquid 201 is, for example, cellulose that promotes moisture permeation with respect to a surfactant (any one of anionic, cationic, nonionic, or a mixture of two or more thereof). And a solution to which a base such as hydroxypropyl cellulose and a talc fine powder are added. Furthermore, fine particles can be contained.

  Next, details of the treatment liquid coating apparatus 200 will be described with reference to FIGS. 2 is a schematic side view of a coating unit of the processing liquid coating apparatus, FIG. 3 is a schematic side view of a processing liquid supply unit of the processing liquid coating apparatus, and FIG. 5 is a cross-sectional explanatory view taken along line AA in FIG. 4, FIG. 6 is a side explanatory view similar to FIG. 4, and FIG. 7 is a cross-sectional explanatory view taken along line BB in FIG.

  First, as shown in FIG. 2, the application unit 208 performs processing on the conveyance roller 235 that conveys the paper 100, the application roller 232 that applies the treatment liquid 201 to the paper 100 so as to face the conveyance roller 235, and the application roller 232. A squeeze roller 233 for supplying the liquid 201 and thinning the liquid film. The rotation direction of each roller is the direction indicated by the arrow in FIG.

  These rollers are arranged such that the application roller 232 is in contact with the conveyance roller 235 and the squeeze roller 233 is in contact with the application roller 232. Then, a liquid film layer 201c of the processing liquid 201 supplied by the squeeze roller 233 and the application roller 232 is formed, and is transferred to the conveyance roller 235 side by the rotation of the application roller 233 (in the direction indicated by the arrow in FIG. 2). It is applied to a recording medium (paper 100) that does not.

  In order to supply the treatment liquid 201 from above the application roller 232 and the squeeze 233, a space 241 is formed on the two rollers 232 and 233 in the application unit 208 in contact with the application roller 232 and the squeeze 233. The supply head 234 which comprises the process liquid supply part arrange | positioned in this way is provided.

  As shown in FIGS. 3 to 7, the supply head 234 is connected to a container 202 at a central portion which is the uppermost portion (a portion having a high height position). Also, suction paths 205 are respectively connected between the both ends of the lower height position and the container 202.

  Thus, by connecting the suction path 205 to the container 202, there is a merit that even if the processing liquid enters the suction path, it can be recovered in the container 202. However, the present invention is not limited to this, and the suctioned air is discharged. Any configuration is possible.

  Here, the liquid conveyance path 204 is provided with an electromagnetic valve 218 for opening and closing the path. A suction pump 203 is provided in the suction path 205, and the end of the suction path 205 on the container 202 side is connected to the upper part of the container 202 (position higher than the liquid level of the processing liquid 201). The container 202 is provided with an air release path 216 having an air release valve (electromagnetic valve) 206 that opens the inside of the container 202 to the atmosphere.

  In addition, a liquid level detection pin (electrode) 207 is provided in the supply head 234 as detection means for detecting the liquid level of the processing liquid in the space 241.

Next, the operation of the treatment liquid coating apparatus 200 will be described with reference to the flowchart of FIG.
When the coating apparatus 200 receives a coating operation signal from an apparatus main body control unit (not shown), the coating apparatus 200 starts the processing liquid supply operation. First, the suction pump 203 is turned on, and the space 241 in the supply head 234, the liquid transport path 204, By sucking air (or processing liquid) in the suction path 205, the pressure in the space 241, the liquid transport path 204, and the suction path 205 in the supply head 234 is set to a negative pressure state compared to the atmosphere. When a predetermined negative pressure is formed by performing suction for a predetermined time, the atmosphere release valve 206 of the container 202 is turned on to open the container 202 to the atmosphere.

  Thereafter, the electromagnetic valve 218 of the liquid transport path 204 is turned on (opened) to open the liquid transport path 204. As a result, the processing liquid 201 is supplied from the container 202 into the space 241, the liquid transport path 204, and the suction path 205 in the supply head 234 that are under negative pressure.

  Here, the configuration is shown in which the negative pressure in the supply head 234 as shown in FIG. 3 is used for supply, but, for example, the minute gap shown in FIG. 7 is set larger to increase the air flow. In the case of ensuring, a configuration may be adopted in which a separate supply pump is provided to supplement the supply pressure.

  Further, the liquid level of the container 202 of the processing liquid 201 is set at a position lower than the supply head 234, and a negative pressure due to a water head difference is generated in the supply head 234 even after the processing liquid is supplied.

  Then, when the liquid level detection pin 207 in the supply head 234 detects the liquid level of the processing liquid 201, the electromagnetic valve 218 is turned off (closed) to shut off the liquid conveyance path 204, so that the processing liquid 201 Supply is stopped.

  Here, as described above, the supply head 234 is provided with the inlet portion (supply port portion) 204a of the liquid transport path 204 at a substantially central portion, and the processing liquid 201 is supplied into the supply head 234 from the vicinity of the center. In addition, suction ports 205a of the suction path 205 are disposed at both ends of the supply head 234 and are connected to the suction pump 203. By operating the suction pump 203, the inside of the supply head 234 is set to a negative pressure.

  In this case, as shown in FIG. 7, the liquid level is controlled so that the layer of the treatment liquid 201 and the air layer 242 are formed in the space 241 in the supply head 234, and the opening (suction port) of the suction path 205 is controlled. Part) 205 a is provided at a position above the supply head 234 where the air layer 242 is formed, so that only the air is sucked by the suction pump 203 via the suction path 205. By sucking only air, the load applied to the suction pump 203 can be reduced, energy saving can be achieved, and the cost and life of the pump can be extended. Further, it is not necessary to connect the suction path to the container 202, and the configuration can be simplified.

  Returning to FIG. 8, the control unit of the apparatus main body confirms the application signal of the next sheet, continues the liquid level detection until the sheet runs out, and keeps the liquid level in the supply head 234 constant. During this time, the suction pump 203 continues to operate and makes the supply head 234 have a negative pressure.

  As described above, the space 241 in the supply head 234 is set to a negative pressure by the suction pump 203, and as shown in FIG. 7, the gap between the supply head 234, the application roller 232, and the squeeze roller 233 moves toward the inside of the head. The form in which the flow of air is generated and the processing liquid 201 is held inside the head 234 can be maintained.

  That is, the processing liquid 201 supplied to the supply head 234 accumulates on the nip portion 244 of the application roller 232 and the squeeze roller 233 as shown in FIGS. 5 and 7, and the supplied processing liquid 201 gradually becomes a nip. It moves toward the ends of the rollers 232 and 233 along the portion 244. As shown in FIGS. 5 to 7, both ends of the supply head 234 are in contact with the rollers 232 and 233 to form a sealed space, but it is difficult to completely seal the nip 244. As shown in FIGS. 6 and 7, when there is a minute gap 245, the processing liquid 201 leaks out of the supply head 234.

  Thus, by making the inside of the supply head 234 have a negative pressure, air flows from the minute gap 245 toward the inside of the head, and the flow of air prevents the processing liquid 201 from leaking from the minute gap 245. In other words, the processing liquid 201 is prevented from leaking out from the minute gap 245 by air pressure.

  As described above, by using the air flow, the leakage of the processing liquid can be prevented relatively easily.

Here, Comparative Example 1 will be described with reference to FIGS. 9 to 11 and Comparative Example 2 with reference to FIG.
In the first comparative example, the processing liquid 201 in the liquid tray 534 is pumped up by the squeeze roller 233, is made into a liquid film layer 201 a state by the regulating roller 536, and is supplied to the application roller 232 by the squeeze roller 233.

  In the configuration of the first comparative example, the processing liquid 201 transferred from the squeeze roller 233 is accumulated as a processing liquid 201 b in the valley between the squeeze roller 233 and the application roller 232. At this time, as shown in FIGS. 10 and 11, excess liquid film layers of the processing liquid are swollen from the roller surface at both ends of the two rollers 232 and 233 to generate ring-shaped expansion portions 201d and 201f. This is a phenomenon that occurs because both ends of the rollers 232 and 233 are liable to come off from the ends to remain at the ends due to surface tension.

  In this case, the length of the roller is made larger than the width of the paper so that the liquid transfer to the paper does not come into contact with the ring-shaped convex portion 201d. However, when the amount of the ring-shaped inflating portions 201d and 201f increases, as shown in FIG. 10, the fluid detaches from the roller 232 as shown by the liquid 201e.

  In Comparative Example 2, the application roller 232 is disposed above the squeeze roller 233, the transport roller 235 is disposed above the application roller 233, and the processing liquid of the ring-shaped expansion portion generated on the application roller 232 is liquid below the gravity. The configuration is such that it is dropped onto the tray 234.

  In the configuration of Comparative Example 2, the processing liquid is applied to the sheet on the lower surface of the sheet. However, when a treatment liquid is applied as a pretreatment for an ink jet recording apparatus or the like, the treatment liquid is preferably applied immediately before printing as much as possible. This is because the reaction between the treatment liquid and the ink can be performed in a liquid state. For this reason, when the treatment liquid is applied by the ink jet recording apparatus, it is usually preferable to apply the treatment liquid to the upper surface of the recording medium. In the configuration of Comparative Example 2, it is not possible to meet the requirement for applying the treatment liquid in such an ink jet recording apparatus.

  In addition, if the coating is relatively slow, such a natural fall can be expected. However, when the recording speed increases and the rotation speed of the roller increases, all the droplets collected to the extent that they fall are centrifuged by the rotation of the roller. The problem will not be solved because it will be scattered in the device by force.

  In addition, the treatment liquid is scattered to reduce the use efficiency of the treatment liquid and increase the cost. In addition, the inside of the apparatus may be soiled or the inside of the apparatus may be corroded.

  On the other hand, according to the above embodiment, as described above, the treatment liquid can be applied to the upper surface of the paper, and the scattering of the treatment liquid from the roller can be reduced. In addition, the treatment liquid can be held in the supply head using the flow of air, the use efficiency of the treatment liquid can be improved, the inside of the apparatus can be soiled, and corrosion can be prevented.

  As described above, the supply unit includes a supply head disposed so as to form a space on the two rollers in contact with the application roller and the squeeze roller, and a suction unit connected to the space in the supply head. The processing liquid can be applied to the upper surface of the paper by adopting a configuration in which the space inside the supply head is made negative by the suction means and air is sucked into the interior through the gap between the supply head, the application roller, and the squeeze roller. In addition, the scattering of the processing liquid from the roller can be reduced.

  In the above embodiment, the liquid level in the supply head 234 is kept constant, and only air is sucked. However, even if the liquid level is detected by the electrode pin 207, the electromagnetic valve 208 of the liquid transfer path 204 is turned on. If the state is left as it is, the processing liquid 201 in the supply head 234 can be circulated. In this way, when the dirt and foreign matter in the supply head 234 are to be cleaned, the processing liquid 201 is returned to the container 202 and removed, or the processing liquid 201 in the supply head 234 is replaced to change the quality due to changes over time. Can be prevented.

  Further, in the above-described embodiment, the inside of the supply head 234 is set to a negative pressure using a suction pump capable of sucking air and liquid, and air is sucked into the supply head 234 from a minute gap. In this way, the path switching valve 209 is provided in the suction path 205, and when the air inside the supply head 234 is sucked, the path is switched to the path 205B and sucked using the suction fan 210, and when the processing liquid 201 is sucked, the path is switched to the path 205A. Thus, suction can be performed by the suction pump 203. By using a fan as the suction means, more air can be stably sucked, and leakage of the processing liquid from the head 234 to the outside can be prevented more reliably.

Next, an example of the operation from the printing process to the stop of the printing process in the above-described image forming apparatus will be described with reference to the flowcharts of FIGS.
First, referring to FIG. 14, when an image output request is received, it is determined whether or not the processing liquid (setting agent) application function is set to be effective.

  When the treatment liquid application function is set to be effective, the pump 203 of the treatment liquid application apparatus 200 is driven to supply the treatment liquid 201 from the container 202 to the supply head 234 of the application unit 208 as described above. . Then, the application roller 232 and the squeeze roller 233 rotate. Then, after the liquid level is detected by the liquid level detection sensor 207 and the width of the liquid pool is sufficiently widened, the electromagnetic valve 218 is closed to stop the supply of the processing liquid 201. In order to detect the spread of the liquid pool, the liquid level detection sensor 207 is preferably provided at the end of the supply head as much as possible.

  Although the case where the liquid level detection sensor 207 detects the amount of liquid in the supply head 234 has been described here, when a sensor is not used, for example, when a predetermined time elapses from the start of the supply operation The supply can also be stopped.

  Thereafter, the process proceeds to the process shown in FIG. 15 and the image output operation is started. In the image output operation, the recording medium (paper) 100 is fed from the paper feeding unit (paper feeding cassette 103), and the recording medium 100 is sent to the conveyance belt 102, and is applied onto the recording medium 100 by the application roller 232. The processing liquid 201 is applied, and the printing operation is started when the leading end of the recording medium 100 reaches the printing position by the head unit 101. Then, after the recording medium 100 for which printing has been completed is discharged, the above-described processing from the paper feed is repeated until printing for the number of printed sheets is completed, and printing is terminated when the predetermined number of printed sheets is reached. Thereafter, when the image output request is made again, the printing operation is performed again.

  Then, when the predetermined number of prints has been reached and there is no next image output request, the printing is terminated and the process proceeds to the end operation of the coating apparatus shown in FIG. Here, the operation of supplying the liquid to the supply head 234 is ended, the processing liquid in the nip portion 244 is collected, and the rotation of the rollers 232 and 233 is ended.

  On the other hand, in FIG. 14, for example, when it is not necessary to apply the treatment liquid by using a special recording medium, the treatment liquid application function is set to be invalid. Then, printing is performed without applying the treatment liquid 201. In the non-application printing mode, the recording medium (paper) 100 is fed from the paper feeding unit (paper feeding cassette 103), and the recording medium 100 is sent to the conveyance belt 102. The printing operation starts when the print position by the head unit 101 is reached. Then, after the recording medium 100 for which printing has been completed is discharged, the above-described processing from the paper feed is repeated until printing for the number of printed sheets is completed, and printing is terminated when the predetermined number of printed sheets is reached.

  In the above embodiment, the processing liquid coating apparatus is described as applying the processing liquid to the paper before image formation. However, the processing liquid is applied on the paper on which the image is formed on the downstream side of the recording head unit. It can also be set as the structure which apply | coats.

  The processing liquid coating apparatus according to the present invention can also be applied to, for example, an electrophotographic image forming apparatus. For example, the resin fine particles are quickly fixed to the medium without disturbing fine particles containing resin such as toner on the medium such as paper, and after applying the fixer to the medium to which the resin fine particles are adhered. In addition, the present invention can also be applied to a fixing method and a fixing device, and an image forming method and an image forming apparatus using a fixing solution of resin fine particles capable of being applied in a minute amount so as not to cause a residual oil feeling.

100 Recording medium (paper)
DESCRIPTION OF SYMBOLS 101 Recording head unit 102 Conveyance belt 103 Paper feed tray 200 Processing liquid coating apparatus 201 Processing liquid 202 Container 203 Suction pump 204 Liquid conveyance path 205 Suction path 206 Atmospheric release valve 207 Liquid level detection sensor 208 Application unit 218 Electromagnetic valve 232 Application roller 233 Squeeze roller 234 Supply head 235 Conveyance roller 244 Nip part 245 Clearance

Claims (5)

Image forming means for forming an image on a recording medium;
A coating apparatus for coating a treatment liquid on the recording medium,
The coating apparatus includes at least a transport roller that transports the recording medium, a coating roller that applies a processing liquid to the recording medium, and a squeeze roller that thins the film of the processing liquid on the coating roller; Supply means for supplying the treatment liquid onto the application roller and the squeeze roller,
The supply means includes a supply head disposed so as to contact the application roller and the squeeze roller to form a space on the two rollers, and a suction means connected to the supply head,
When supplying the processing liquid onto the application roller and the squeeze roller, the suction unit is operated to create a negative pressure in the space in the supply head from the gap between the supply head, the application roller, and the squeeze roller. An image forming apparatus that controls to suck air into the supply head.   The image forming apparatus according to claim 1, wherein the suction unit sucks air from above the space of the supply head to supply the processing liquid into the supply head.   Means for detecting the liquid level of the processing liquid in the supply head, controls the supply of the processing liquid so that an air layer is formed in the space in the supply head, and the suction port of the suction means has the suction port The image forming apparatus according to claim 1, wherein the image forming apparatus is provided at a portion where an air layer is formed.   4. The storage device according to claim 1, further comprising a storage unit configured to store the processing liquid supplied to the space in the supply head, wherein the storage unit is disposed at a position lower than the space of the supply head. The image forming apparatus described in 1. In a processing liquid application apparatus for applying a processing liquid to a recording medium,
At least a transport roller for transporting the recording medium, a coating roller for coating a processing liquid on the recording medium, a squeeze roller for thinning a film of the processing liquid on the coating roller, and the processing liquid Supply means for supplying onto the application roller and the squeeze roller,
The supply means includes a supply head disposed so as to contact the application roller and the squeeze roller to form a space on the two rollers, and a suction means connected to the supply head,
When supplying the processing liquid onto the application roller and the squeeze roller, the suction unit is operated to create a negative pressure in the space in the supply head from the gap between the supply head, the application roller, and the squeeze roller. A treatment liquid coating apparatus that performs control to suck air into the supply head.

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