JP5459489B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus including an apparatus for applying a processing liquid.

  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

  In the apparatus for applying the treatment liquid as described above, the transport roller for conveying the recording medium, the application roller for applying the treatment liquid to the recording medium, and the film of the treatment liquid on the application roller in thin contact with the application roller. It is conceivable that the application amount of the processing liquid to the recording medium is adjusted by slipping each other roller with a linear speed difference between the rotation of the application roller and the rotation of the squeeze roller. .

  However, when the operation of the coating apparatus is started from the state in which the processing liquid is not supplied to the coating roller, since the processing liquid is not attached to the squeeze roller, the coating roller and the squeeze roller have a linear speed difference. When rotated, the rollers may be scraped without slipping between the rollers, and the rollers may be damaged.

  In the case of general application, as a countermeasure against this, there are a method of supplying a processing liquid and starting rotation after sufficiently spreading between the application roller and the squeeze roller, and a method of adding the processing liquid after temporarily separating the rollers. However, in the case of a treatment liquid to be applied to a recording medium such as paper, since there are many relatively high-viscosity materials to keep on the surface of the recording medium, it is difficult to spread over the entire surface of the roller without rotating the roller. There is a problem in that a large amount of processing liquid is consumed before spreading is completed. Similarly, there is also a problem that in the state where the rollers are separated from each other, the force for extending the processing liquid in the roller axial direction does not work and the spreading cannot be performed.

  The present invention has been made in view of the above problems, and an object of the present invention is to prevent the roller from being damaged even when the application roller and the squeeze roller are rotated with a difference in linear velocity.

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 device includes:
Having a plurality of rollers,
The plurality of rollers include at least a conveyance roller that conveys the recording medium, an application roller that applies a treatment liquid to the recording medium, and a contact with the application roller that has a difference in rotation and linear velocity between the application rollers. And a squeeze roller that forms a film of the treatment liquid on the application roller,
The application roller and the squeeze roller are configured to rotate at a constant speed when the application apparatus starts supplying the treatment liquid to the application roller without the treatment liquid.

  Here, after detecting that the rotational torque of at least one of the application roller and the squeeze roller is equal to or less than a predetermined value, the application roller and the squeeze roller are rotated with a linear speed difference. It can be configured to be.

  In addition, after detecting that the liquid level of the processing liquid accumulated above the contact portion between the application roller and the squeeze roller has reached a predetermined position, the application roller, the squeeze roller, Can be configured to rotate.

  Further, when the treatment liquid is replenished to the application roller, the application roller and the squeeze roller can be rotated at a constant speed.

  According to the image forming apparatus of the present invention, the application roller and the squeeze roller are rotated at a constant speed at the start of the operation of the application apparatus that supplies the application liquid to the application roller without the application liquid in the application roller. Therefore, even when the application amount is adjusted by providing a linear speed difference between the application roller and the squeeze roller, damage to the roller can be prevented.

1 is an overall configuration diagram illustrating an example of an image forming apparatus according to a first embodiment of the present invention. It is typical side surface explanatory drawing of the application part of the apparatus. It is typical side surface explanatory drawing of the application part of the coating device in 2nd Embodiment of this invention. It is a plane explanatory drawing similarly. It is a flowchart with which it uses for description of the printing operation in 1st Embodiment. FIG. 6 is a flowchart for explaining an image output operation following FIG. 5. It is a flowchart with which it uses for description of the printing mode without application following FIG. It is a flowchart with which it uses for description of the printing operation in 2nd Embodiment. It is explanatory drawing.

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 first embodiment of 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 coating device 200 that coats the processing liquid onto the paper 100 that is a member to be coated are provided upstream of the recording head unit 101 in the paper transport 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 coating device 200 via the transport path 135, and the treatment liquid is applied by the coating device 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 coating apparatus 200 is a recording medium that includes a container 202 containing a 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 a supply path 204. And an application unit 208 that applies to 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, details of the coating unit 208 of the coating apparatus 200 will be described with reference to FIG. FIG. 2 is a schematic side view of the application part.
The coating unit 208 feeds the processing film 201 to the coating roller 232, the coating roller 232 that applies the processing liquid 201 to the sheet 100, the transporting roller 235 that transports the paper 100, the liquid film ( And a squeeze roller 233 for thinning the film of the treatment liquid 201. 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.

  With this configuration, as shown in FIG. 2, when applying the processing liquid 201 to the paper 100 by the coating apparatus 200, the processing liquid in the liquid tray 234 is rotated by the squeeze roller 233 rotating in the direction indicated by the arrow. 201 is scooped up on the surface of the squeeze roller 233, transferred by the rotation in the state of the liquid film layer 201a, and collected on the valley portion (contact portion: nip portion) between the squeeze roller 233 and the application roller 232 (treatment liquid 201b). .

  Here, the squeeze roller 233 and the application roller 232 are in contact with each other with a constant pressure, and the processing liquid 201b stored in the valley portion is squeezed with pressure when passing between the rollers 233 and 232, and the processing liquid A liquid film layer 201 c of 201 is formed and transferred to the transport roller 235 side by the rotation of the application roller 232.

  The liquid film layer 201c transferred by the application roller 232 is applied to the paper 100 (not shown in FIG. 2).

  At this time, the application amount can be adjusted by giving a linear velocity difference between the application roller 232 and the squeeze roller 233.

  Further, the squeeze roller 233 includes a torque limiter 236. The torque limiter 236 cancels the torque when the torque applied to the squeeze roller 233 exceeds a predetermined value, rotates the application roller 232 and the squeeze roller 233 at a constant speed, and the torque is equal to or less than a predetermined value. The torque is not canceled and the squeeze roller 233 is rotated with the linear speed difference maintained even if there is a linear speed difference between the application roller 232 and the squeeze roller 233.

  Here, at the start of the operation of starting the supply of the processing liquid 201 from the state where the processing liquid 201 is not supplied to the squeeze roller 233 of the coating apparatus 200 (at the time of starting), the coating roller 232 and the squeeze roller 233 are difficult to slip. Torque is generated between the two rollers 232 and 233. At this time, since the torque is canceled by the torque limiter 236, the two rollers 232 and 233 start rotating at a constant speed. This prevents damage to the rollers that occurs because the two rollers 232, 233 do not slip during startup.

  After that, when a liquid film is formed between the squeeze roller 233 and the application roller 232, the two rollers 232 and 233 slip and become below a predetermined torque, so that the torque limiter 236 is released and 2 The two rollers 232 and 233 rotate with the set linear velocity difference.

  As described above, the application roller and the squeeze roller are rotated at a constant speed at the start of the operation of the application apparatus that supplies the application liquid to the application roller without the application liquid. Even when the application amount is adjusted by giving a linear velocity difference to the roller, damage to the roller can be prevented.

  Next, a second embodiment of the present invention will be described with reference to FIGS. Note that FIG. 3 is a schematic explanatory view of a coating portion of the coating apparatus in the same embodiment, and FIG. Here, the rotation of the drive motor 238 is transmitted to the application roller 232 via the gears 239c and 239d and also transmitted to the squeeze roller 233 via the gears 239c, 239b and 239a.

  The gear 239a of the squeeze roller 232 is provided with a clutch 237, and the gear 239d is locked to the squeeze roller 233 (ON state) by turning the clutch 237 ON (valid) / OFF (invalid), or free. It can be in a state (off state).

  Further, the number of teeth (gear ratio) of the gear 239d and the gear 239b is set to the number of teeth that causes a predetermined linear speed difference between the rotation speed of the squeeze roller 233 and the rotation speed of the application roller 232 when the squeeze roller 233 rotates. Has been.

  Here, the on / off control of the clutch 237 is performed when the squeeze roller 232 rotates a predetermined amount, for example, when a predetermined rotation angle is reached, or when the processing liquid accumulates at the contact portion between the squeeze roller 233 and the application roller 232. When it is detected that the liquid level of 201b has reached a predetermined position, the liquid level is switched from off to on.

  Since it comprised in this way, at the time of starting of a coating device (at the time of operation | movement start), the clutch 237 is turned off and the squeeze roller 233 is made into the state which can be freely rotated. Here, when the drive motor 238 is driven, the application roller 232 rotates via the gears 239 c and 239 d, and the squeeze roller 233 that is in contact with the application roller 232 rotates following the application roller 232. Therefore, at the time of start-up (at the start of operation), the two rollers 232 and 233 start rotating at a constant speed.

  This prevents damage to the rollers that occurs because the two rollers 232, 233 do not slip during startup.

  Then, after the squeeze roller 233 rotates a predetermined amount, the clutch 237 is turned on so that the gear 239a is locked to the squeeze roller 233, and the power transmitted from the drive motor 238 is transmitted to the squeeze roller 233. The squeeze roller 233 and the application roller 232 rotate with a linear speed difference by setting the gear ratio between the gear 239d and the gear 239b. At this time, since the processing liquid 201 is supplied to the application roller 232, slip occurs and the roller is not damaged.

Next, an example of the printing process in the first embodiment will be described with reference to flowcharts shown in FIGS.
Referring to FIG. 5, 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, it is determined whether or not a predetermined amount or more of the treatment liquid 201 is in the liquid tray 234. At this time, if a predetermined amount or more of the processing liquid 201 is not contained in the liquid tray 234, the pump 203 is driven to replenish the processing liquid 201 from the container (tank) 202 into the liquid tray 234, and then the predetermined amount. If the above processing liquid 201 is contained, the operation of the coating unit 208 is started as it is.

  Then, rotation of the application roller 232 and the squeeze roller 233 of the application unit 208 is started. At this time, the squeeze roller 233 is set so as to rotate with a difference in linear velocity with respect to the application roller 235. However, at the start-up time when the liquid film of the processing liquid 201 is not formed on the squeeze roller 233, the two rollers 232, Torque is generated when the 233 grips each other. A specified value B is set in the torque limiter 236 for the torque value A at this time. The initial rotation of the rollers 233 and 232 is A> B, and the torque limiter 236 is activated, so that the squeeze roller 233 starts rotating at the same speed as the application roller 232.

  Thereafter, when a liquid film is formed on the squeeze roller 233 and slipping begins with the application roller 232, the torque value A between the two rollers 233 and 232 decreases, and the specified value (specified torque) set in the torque limiter 236 Value) B (A ≦ B). As a result, the torque limiter 236 is released, the squeeze roller 233 rotates at the set linear velocity, and the squeeze roller 233 and the application roller 232 rotate with a linear velocity difference.

  Thereafter, the process proceeds to the process shown in FIG. 6 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 tray 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.

  On the other hand, in FIG. 5, 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.

Next, an example of the printing process in the second embodiment will be described with reference to the flowchart shown in FIG.
First, similarly to the printing process of the first embodiment, 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, it is determined whether or not a predetermined amount or more of the treatment liquid 201 is in the liquid tray 234. At this time, if a predetermined amount or more of the processing liquid 201 is not contained in the liquid tray 234, the pump 203 is driven to replenish the processing liquid 201 from the container 202 into the liquid tray 234, and then a processing of a predetermined amount or more. If the liquid 201 is contained, the operation of the application unit 208 is started as it is.

  Then, rotation of the application roller 232 and the squeeze roller 233 of the application unit 208 is started. At this time, as described in the second embodiment, since the clutch 237 is in the OFF state at the initial stage of rotation, the squeeze roller 233 rotates with the application roller 232, so that the squeeze roller 233 is the same as the application roller 232, etc. Start spinning at speed.

  Thereafter, when the processing liquid 201b accumulates at the contact portion between the squeeze roller 233 and the application roller 232 and the liquid level reaches a predetermined position, the clutch 237 is turned on. As a result, the squeeze roller 233 starts rotating with the driving force transmitted from the gear train, and the squeeze roller 233 and the application roller 232 rotate with a difference in linear velocity.

  The subsequent image output operation and the non-application printing mode when the processing liquid application valid setting is invalid are the same as those described with reference to FIGS.

  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 Conveyor belt 103 Paper feed tray 200 Processing liquid coating apparatus 201 Processing liquid 208 Application | coating part 232 Application roller 233 Squeeze roller 235 Conveyance roller

Claims (4)

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 device includes:
Having a plurality of rollers,
The plurality of rollers include at least a conveyance roller that conveys the recording medium, an application roller that applies a treatment liquid to the recording medium, and a contact with the application roller that has a difference in rotation and linear velocity between the application rollers. And a squeeze roller that forms a film of the treatment liquid on the application roller,
Image forming characterized in that the application roller and the squeeze roller are rotated at a constant speed at the start of the operation of the application device for supplying the treatment liquid to the application roller without the treatment liquid in the application roller. apparatus.   After detecting that the rotational torque of at least one of the application roller and the squeeze roller is equal to or less than a predetermined value, the application roller and the squeeze roller are rotated with a linear speed difference. The image forming apparatus according to claim 1, wherein:   After detecting that the liquid level of the processing liquid accumulated above the contact portion between the application roller and the squeeze roller has reached a predetermined position, the application roller and the squeeze roller are rotated with a difference in linear velocity. The image forming apparatus according to claim 1, wherein:   4. The image forming apparatus according to claim 1, wherein when the processing liquid is supplied to the application roller, the application roller and the squeeze roller are rotated at a constant speed.

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