JP2012152923A - Image forming apparatus and processing liquid coating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the following problem:in order to provide a compact coating apparatus, the capacity of a processing liquid holding section for holding the processing liquid to be supplied to a coating roller must be reduced, resulting in difficulty in maintaining a constant amount of liquid.SOLUTION: A liquid chamber 234 includes: a first liquid level sensor 261 detecting that the liquid level of a processing liquid 201 is a first level, and a second liquid level sensor 262 detecting that the liquid level of a processing liquid 201 is a second level higher than the first level. The processing liquid 201 to be supplied to the liquid chamber 234 is controlled by controlling drive of a pump 203 based on the detection results of the first and second liquid level sensors 261, 262, to control the liquid level of the processing liquid 201 in the liquid chamber 234 before driving a coating roller 232 at the second level, and control the liquid level of the processing liquid 201 in the liquid chamber 234 during driving the coating roller 232 at the first level.

Description

  The present invention relates to an image forming apparatus and a processing liquid coating apparatus, and more particularly to an image forming apparatus and a processing liquid coating apparatus that apply a processing liquid to a recording medium.

  2. Description of the Related Art As an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, a plotter, and a complex machine of these, for example, a liquid ejection recording type image forming apparatus (inkjet recording apparatus) using a recording head that ejects 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 image, and 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, it is conventionally known that a pretreatment liquid is applied to a recording medium with an application roller. In this case, in order to prevent coating unevenness due to insufficient supply of the pretreatment liquid to the application roller and liquid leakage from the pretreatment liquid tank due to excessive supply of the pretreatment liquid to the application roller, the liquid of the pretreatment liquid in the pretreatment liquid tank There is a liquid level detecting means for detecting the height of the surface so that the amount of the pretreatment liquid in the pretreatment liquid tank is kept within a certain range (Patent Document 1).

JP 2002-096454 A

  However, in order to reduce the size of the coating apparatus, it is necessary to reduce the volume of the processing liquid holding unit (hereinafter also referred to as “liquid chamber”) that holds the processing liquid supplied to the coating roller. It has become difficult to keep the amount of liquid constant. In particular, immediately after the start of coating, the processing liquid must be supplied from the liquid chamber to the coating roller at a stretch, so that the amount of liquid in the liquid chamber decreases rapidly. On the other hand, since the processing liquid supplied to the application roller returns to the liquid chamber at the end of the coating operation, the volume of the processing liquid in the liquid chamber is more than the capacity that can be held in the liquid chamber, and the processing liquid is discharged from the liquid chamber. There is a problem of overflowing.

  The present invention has been made in view of the above problems, and aims to keep the processing liquid in the processing liquid holding unit constant, stabilize the supply of the processing liquid to the coating roller, and perform stable coating. And

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 treatment liquid application device for applying a treatment liquid to the recording medium,
The treatment liquid application means is at least
An application roller for applying the treatment liquid to the recording medium;
A squeeze roller that supplies the treatment liquid and thins the liquid film on the coating roller;
A treatment liquid holding unit for holding the treatment liquid supplied to the squeeze roller;
Supply means for supplying the processing liquid to the processing liquid holding unit;
Means for controlling the supply from the supply means to the treatment liquid holding unit,
The processing liquid holding unit includes a first liquid level detecting unit that detects that the liquid level of the processing liquid is a first height position, and a second height position that is higher than the first height position. A second liquid level detection means for detecting that there is,
The control means controls the supply from the supply means to the treatment liquid holding part based on the detection results of the first and second liquid level detection means, and the treatment liquid holding part before driving the application roller. The liquid level height of the processing liquid is set to the second height position, and the liquid level height of the processing liquid of the processing liquid holding unit when the application roller is driven is controlled to the first height position. It was.

  Here, the means for controlling may be configured to control the liquid level height of the processing liquid of the processing liquid holding part immediately after the start of driving of the application roller to the second height position.

  Further, when the control means cannot detect immediately after the start of driving of the application roller that the liquid level of the processing liquid in the processing liquid holding unit has become lower than the second height position, it is determined as abnormal. The image forming operation can be stopped.

  Further, when the controlling means detects that the liquid level of the processing liquid in the processing liquid holding part has become lower than the first height position immediately after the start of driving the application roller, it is determined as abnormal. The image forming operation can be stopped.

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,
An application roller for applying the treatment liquid to the recording medium;
A squeeze roller that supplies the treatment liquid and thins the liquid film on the coating roller;
A treatment liquid holding unit for holding the treatment liquid supplied to the squeeze roller;
Supply means for supplying the processing liquid to the processing liquid holding unit;
Means for controlling the supply from the supply means to the treatment liquid holding unit,
The processing liquid holding unit includes a first liquid level detecting unit that detects that the liquid level of the processing liquid is a first height position, and a second height position that is higher than the first height position. A second liquid level detection means for detecting that there is,
The control means controls the supply from the supply means to the treatment liquid holding part based on the detection results of the first and second liquid level detection means, and the treatment liquid holding part before driving the application roller. The liquid level height of the processing liquid is set to the second height position, and the liquid level height of the processing liquid of the processing liquid holding unit when the application roller is driven is controlled to the first height position. It was.

  According to the image forming apparatus and the processing liquid coating apparatus according to the present invention, the processing liquid holding unit includes a first liquid level detection unit that detects that the liquid level of the processing liquid is the first height position; And a second liquid level detecting means for detecting that the second height position is higher than the first height position, and the means for controlling is supplied based on the detection results of the first and second liquid level detecting means. The supply of the processing liquid from the means to the processing liquid holding part is controlled so that the liquid level of the processing liquid in the processing liquid holding part before driving the coating roller is set to the second height position, and the processing liquid holding part is Since the liquid level of the processing liquid is controlled to the first height position, the processing liquid in the processing liquid holding unit is kept constant, the supply of the processing liquid to the coating roller is stabilized, and stable coating is performed. be able to.

1 is an overall configuration diagram of an image forming apparatus according to an embodiment of the present invention. It is a typical side surface explanatory view before the start of the application | coating operation | movement used for description of the application part of a process liquid coating device. It is a typical side surface explanatory view at the time of application operation similarly used for explanation of an application part of a processing liquid application device. It is a block explanatory drawing with which the control part of the apparatus is provided. It is a flowchart with which it uses for description of the liquid level height control of the liquid chamber by the control part.

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is an overall configuration diagram of the image forming apparatus according to the embodiment.
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 application device (means) 200 for applying a processing liquid to the paper 100 that is a member to be applied are provided upstream of the recording head unit 101 in the paper conveyance direction.

  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 processing liquid coating apparatus 200 via the transport path 135, and the processing liquid is applied by the processing liquid coating apparatus 200 and sent onto the transport belt 102 and held there.

  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 processing liquid coating apparatus 200 includes a container 202 that contains the processing liquid 201, a pump 203 that pumps the processing liquid 201 from the container 202, and the processing liquid 201 that is supplied by the pump 203 via the supply path 204. And a coating unit 208 that coats the paper 100.

  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, the coating unit 208 of the treatment liquid coating apparatus 200 will be described with reference to FIGS. 2 is a schematic side view of the application unit before the start of the application operation, and FIG. 3 is a schematic side view of the application unit during the application operation.
The application unit 208 supplies a conveyance roller 235 that conveys the paper 100 that is a recording medium, an application roller 232 that applies the treatment liquid 201 to the paper 100, and the treatment liquid 201, and thins the liquid film on the application roller 232. And a liquid chamber 234 which is a processing liquid holding unit for holding the processing liquid 201 to be supplied to the squeeze roller 233, and the liquid chamber 234 contains the processing contained in the container 202 described above. The liquid 201 is supplied by the pump 203 through the supply path 204. 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. The squeeze roller 233 is disposed so as to be immersed in the processing liquid 201 in the liquid chamber 234.

  The liquid chamber 234 includes liquid level sensors 261 and 262 which are first and second liquid level detecting means for detecting the height of the processing liquid 201 in the liquid chamber 234. The first liquid level sensor 261 detects that the liquid level of the processing liquid 201 is equal to or higher than the first height position, and the second liquid level sensor 262 is a second height position higher than the first height position. It is detected that it is above.

Next, an outline of the control unit of the image forming apparatus will be described with reference to the block explanatory diagram of FIG.
The main control unit 501 includes a microcomputer including a CPU, ROM, RAM, I / O, and the like that controls the entire image forming apparatus. The main control unit 501 processes the received image data and transfers the processed image data to the print control unit 502. The print control unit 502 controls driving of the recording head 101 via the head driver 503 according to the image data. To eject droplets. In addition, the main control unit 501 drives and controls the conveyance motor 505 that rotates the conveyance belt 102 through the motor driving unit 504 to convey the paper 100.

  The application control unit 510 also serves as a control unit in the present invention, and controls each part of the processing liquid application apparatus 200. In response to a coating request from the main control unit 501, the coating control unit 510 drives the pump 203 through the pump driving unit 511 and controls the coating roller 232 through the roller driving unit 512 in order to control the processing liquid coating operation. The motor 513 for rotating the squeeze roller 233 is driven and controlled. Further, according to the detection results of the first and second liquid level sensors 261 and 262, the pump 203 is driven to control the supply of the processing liquid 201 to the liquid chamber 234.

Next, the liquid level control of the liquid chamber by the application control unit will be described with reference to the flowchart of FIG.
First, when a coating operation start signal is given from the main control unit 501, whether or not the second liquid level sensor 162 detects the liquid level of the processing liquid 201 in the liquid chamber 234 (second liquid level sensor ON). If the second liquid level sensor 262 is not ON, the liquid level of the processing liquid 201 in the liquid chamber 234 is not changed until the second liquid level sensor 262 is turned ON, that is, as shown in FIG. The pump 203 is driven to supply the processing liquid 201 to the liquid chamber 234 until it reaches the second height position.

  When the second liquid level sensor 262 is turned on, the application roller 232 and the squeeze roller 233 start to rotate. Here, when the squeeze roller 233 rotates, the processing liquid 201 in the liquid chamber 234 is supplied to the liquid pool portion 260 between the application roller 232 and the squeeze roller 235.

  In this way, by increasing the liquid level in the liquid chamber 234 to the position (second height position) of the second liquid level sensor 262, the liquid chamber 234 is driven by the squeeze roller 233 immediately after the application roller 232 starts to be driven. The amount of the processing liquid 201 supplied to the liquid reservoir 260 can be supplied in advance, and when the squeeze roller 233 starts driving, the processing liquid 201 in the liquid chamber 234 is instantaneously lost. Can be prevented. Further, by this action, the volume of the processing liquid 201 in the liquid chamber 234 can be made relatively small, so that the drying of the processing liquid 201 in the liquid chamber 234 can be prevented.

  As described above, the processing liquid 201 supplied to the liquid pool 260 is extended by the contact between the application roller 232 and the squeeze roller 233, and a liquid film layer is formed on the surface layer of the application roller 232, and the application roller 232 rotates. The liquid film layer is transferred to a recording medium (paper 100) (not shown) on the conveying roller 235 side and applied.

  Thereafter, when application is started, it is determined whether or not the first liquid level sensor 261 has detected the liquid level of the processing liquid 201 (first liquid level sensor 261 ON), and if the first liquid level sensor 261 is ON. For example, it is determined whether or not an application operation end signal has been received (application operation end signal ON). If an application operation end signal has not been received, the process returns to the determination process of whether or not the first liquid level sensor is ON. If the first liquid level sensor is not ON before receiving the application operation end signal (when the liquid level is lower than the first height position), the pump 203 is driven and the processing liquid is supplied to the liquid chamber 234. 201 is supplied. When the application operation end signal is turned ON, the application roller 232 and the squeeze roller 233 are stopped.

  That is, during the coating operation, as shown in FIG. 3, the processing liquid is set such that the liquid level of the processing liquid 201 in the liquid chamber 234 becomes a height (first height position) detected by the first liquid level sensor 261. A supply operation 201 is performed.

  Thereby, during the application operation, the liquid level is maintained at the first height position lower than the second height position. Therefore, at the end of the application operation, the treatment liquid 201 around the squeeze roller 233 and the treatment liquid 201 in the liquid pool 260 are disposed. Even if the liquid returns to the liquid chamber 234, the liquid chamber 234 does not become full, and leakage (overflow) of the processing liquid 201 from the liquid chamber 234 can be prevented. Moreover, since the capacity | capacitance of the process liquid 201 of the liquid chamber 234 can be made comparatively small by this effect | action, the drying of the process liquid 201 in the liquid chamber 234 can be prevented.

  That is, the first height position detected by the first liquid level sensor 261 is a position where the processing liquid 201 does not overflow from the liquid chamber 234 even if the processing liquid 201 around the squeeze roller 233 and the processing liquid 201 in the liquid pool 260 return. Set to. Moreover, since the volume of the processing liquid in the liquid chamber 206 can be relatively reduced by this action, drying of the processing liquid in the liquid chamber 206 can be prevented.

  At the same time, immediately after the start of application, the second liquid level is detected so that at least a liquid level higher than the detection position by the first liquid level sensor 261 for setting the liquid level of the treatment liquid 201 during the application operation to a predetermined position. The detection position (height) of the liquid level sensor 262 is set. As a result, the processing liquid 201 is not supplied to the liquid chamber 234 even when the application is interrupted due to the convenience of the apparatus main body, so that it is possible to prevent the processing liquid 201 in the liquid chamber 234 from increasing. As the processing liquid 201 in the liquid chamber 234 increases for each drive (every operation), the liquid chamber 234 will eventually become full and the processing liquid 201 will overflow from the liquid chamber 234.

  Thus, in the processing liquid holding part, the first liquid level detection means for detecting that the liquid level of the processing liquid is the first height position, and the second height position higher than the first height position. And a second liquid level detecting means for detecting that the application roller is driven by controlling the supply from the supply means to the treatment liquid holding unit based on the detection results of the first and second liquid level detecting means. The liquid level height of the processing liquid in the previous processing liquid holding part is set to the second height position, and the liquid level height of the processing liquid in the processing liquid holding part when the application roller is driven is controlled to the first height position. By doing so, the processing liquid in the processing liquid holding unit can be kept constant, the supply of the processing liquid to the coating roller can be stabilized, and stable coating can be performed.

Next, another embodiment of the present invention will be described.
First, immediately after the start of the coating operation, when the liquid level of the processing liquid 201 in the liquid chamber 234 does not become lower than the second height position, that is, when the second liquid level sensor 262 remains ON, the coating operation is performed. When the operation stops, the processing liquid 201 around the squeeze roller 233 and the processing liquid 201 in the liquid pool 260 may return to the liquid chamber 234 and the processing liquid 201 may overflow from the liquid chamber 234.

  Therefore, immediately after the start of the coating operation, if the second liquid level sensor 262 remains ON (the liquid level is detected), it is determined that there is an abnormality, the coating operation or the image forming operation is stopped, and the second liquid is stopped. Until the surface sensor 262 is not turned on (turned off), for example, if the pump 203 is a reversible pump, the processing liquid 201 is sent back from the liquid chamber 234 to the processing liquid container 202, or the processing liquid is sent to a waste liquid section (not shown). 201 is drained.

  Thereby, overflow of the processing liquid 201 from the liquid chamber 234 can be prevented.

  Next, immediately after the start of the coating operation, when the first and second liquid level sensors 261 and 262 are turned off, that is, the state in which the liquid level of the processing liquid 201 remains lower than the first height position continues. If it is determined that the viscosity of the processing liquid 201 in the liquid chamber 234 has increased due to the drying of the processing liquid 201, it is determined to be abnormal, the coating operation or the image forming operation is stopped, and a waste liquid not shown in the figure. The processing liquid 201 is discharged to the part. That is, when the processing liquid 201 is thickened, a relatively large amount of the processing liquid 201 is pumped up by the squeeze roller 233 immediately after the start of the coating operation, and the processing liquid 201 in the liquid chamber 234 becomes smaller than usual.

  Thereby, it is possible to prevent an increase in the coating amount, which occurs when the thickened processing liquid 201 is applied to the paper, and the paper is wound around the coating roller 232 and jammed.

  In the above-mentioned other embodiments, “immediately after the start of the coating operation” means that the predetermined number of rotations from the start of the coating operation until a predetermined time elapses or from the start of driving of the drive motor that drives the coating roller It can be until the number 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 image forming 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 Conveying belt 103 Paper feed tray 200 Processing liquid coating apparatus 201 Processing liquid 203 Pump 208 Application | coating part 232 Application | coating roller 233 Squeeze roller 234 Liquid chamber (processing liquid holding | maintenance part)
235 Conveying roller 261 First liquid level sensor 262 Second liquid level sensor

Claims (5)

Image forming means for forming an image on a recording medium;
A treatment liquid application device for applying a treatment liquid to the recording medium,
The treatment liquid application means is at least
An application roller for applying the treatment liquid to the recording medium;
A squeeze roller that supplies the treatment liquid and thins the liquid film on the coating roller;
A treatment liquid holding unit for holding the treatment liquid supplied to the squeeze roller;
Supply means for supplying the processing liquid to the processing liquid holding unit;
Means for controlling the supply from the supply means to the treatment liquid holding unit,
The processing liquid holding unit includes a first liquid level detecting unit that detects that the liquid level of the processing liquid is a first height position, and a second height position that is higher than the first height position. A second liquid level detection means for detecting that there is,
The control means controls the supply from the supply means to the treatment liquid holding part based on the detection results of the first and second liquid level detection means, and the treatment liquid holding part before driving the application roller. The liquid level height of the processing liquid is set to the second height position, and the liquid level height of the processing liquid of the processing liquid holding unit when the application roller is driven is controlled to the first height position. An image forming apparatus.   2. The image according to claim 1, wherein the control unit controls the liquid level height of the processing liquid of the processing liquid holding unit immediately after the start of driving of the application roller to the second height position. 3. Forming equipment.   Immediately after the start of driving of the application roller, the control means determines that the liquid level height of the processing liquid in the processing liquid holding unit is lower than the second height position, and determines that there is an abnormality. The image forming apparatus according to claim 1, wherein the forming operation is stopped.   Immediately after the start of driving of the application roller, the control means determines that the liquid level height of the processing liquid in the processing liquid holding unit is lower than the first height position, and determines that there is an abnormality. The image forming apparatus according to claim 1, wherein the forming operation is stopped. In a processing liquid application apparatus for applying a processing liquid to a recording medium,
An application roller for applying the treatment liquid to the recording medium;
A squeeze roller that supplies the treatment liquid and thins the liquid film on the coating roller;
A treatment liquid holding unit for holding the treatment liquid supplied to the squeeze roller;
Supply means for supplying the processing liquid to the processing liquid holding unit;
Means for controlling the supply from the supply means to the treatment liquid holding unit,
The processing liquid holding unit includes a first liquid level detecting unit that detects that the liquid level of the processing liquid is a first height position, and a second height position that is higher than the first height position. A second liquid level detection means for detecting that there is,
The control means controls the supply from the supply means to the treatment liquid holding part based on the detection results of the first and second liquid level detection means, and the treatment liquid holding part before driving the application roller. The liquid level height of the processing liquid is set to the second height position, and the liquid level height of the processing liquid of the processing liquid holding unit when the application roller is driven is controlled to the first height position. A processing liquid coating apparatus characterized by the above.

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